View south in Havasu Canyon, tributary of Grand Canyon, showing the four formations 

comprising the Supai Group near their type localities. The two sandstone monuments in 

the Wescogame Formation, center foreground, are referred to as Wigieeva in legends of 

the Havasupai Indians who consider them to be spirits or deities. Drawing by William I. 

Chesser, 1976.
THE SUPAI GROUP OF 

GRAND CANYON
View in eastern Grand Canyon painted from Yavapai Point on the South Rim in 1936 by 

the famous Swedish artist Gunnar Widforss. The red strata in the middle part of the 

picture consist of the Hermit Shale and the four formations of the Supai Group. Only the 

central part of the original painting is reproduced here.


The Supai Group of 

Grand Canyon

By Edwin D. McKee

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1173

A study of the environment and history of 

four red bed formations, partly marine and 

partly continental, that comprise the Supai 

Group of Grand Canyon, Arizona

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1982
UNITED STATES DEPARTMENT OF THE INTERIOR 

WILLIAM P. CLARK, Secretary

GEOLOGICAL SURVEY 

Dallas L. Peck, Director

First printing 1983 

Second printing 1983

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. 20402
The Supai Group of Grand Canyon 

Contents

[For convenience in cross-referencing, each chapter of this publication has a letter designation]

Page

Foreword ........................................ ix

A. Introduction ................................... 1

B. Introductory summary .............................. 21

C. Stratigraphy and lithology ........................... 29

D. Paleogeography ................................. 51

E. Distribution and age of fauna and flora ................... 75

F. Biostratigraphy of the Watahomigi Formation, by

Mackenzie Gordon, Jr. ........................... 113

G. Pre-Supai buried valleys, by George H. Billingsley and

Edwin D. McKee ............................... 137

H. Erosion surfaces ................................. 155

I. Transgressions and regressions ......................... 177

J. Conglomerates .................................. 187

K. Sandstones .................................... 205

L Environment of deposition of sandstone bodies .............. 245

M. Insoluble residue patterns, by Walter Pierce, A. J.

Gude, III, and Edwin D. McKee ...................... 263

N. Minor sedimentary features, contorted structures,

and homogeneous sedimentary rocks ................... 273

O. Clay mineralogy, by Phoebe L . Hauff and Edwin D. McKee ....... 287

P. Petrography of the Supai Group and Pakoon Limestone, by

Edwin D. McKee and Walter Pierce .................... 333

Q. Stable isotope analyses ............................. 361

R. Aphanitic silica rock ............................... 365

S. Evaporite deposits and magnesian carbonate rocks ............. 375

Measured stratigraphic sections .......................... 389
Cambrian (Devonian Mississippian
Foreword

This comprehensive geological monograph, definitive of the Supai Group of 

rocks in the Grand Canyon region, needs to be put into the proper personal and 

technical perspective and context for the reader. Edwin Dinwiddie McKee, Grand 

Canyon geologist and naturalist, has taken the initiative and dedication in his professional lifetime to document the Paleozoic stratigraphic rock sequence as part 

of the geological history of the Grand Canyon of Arizona a monumental task 

and a truly remarkable record of achievement nearing completion after 50 years of 

devotion and effort!

The Grand Canyon has proved to be one of the World's finest laboratories for 

illustrating various geological principles, especially those related to the sedimentary 

history of stratified rocks. Clear, complete exposures of the strata as far as the eye 

can see and the general lack of structural disturbance offer nearly ideal conditions 

for study of these rocks. Opportunities are exceptionally good for applying geologic 

strategy (scientific method) in testing theories concerning natural processes and 

for demonstrating the detailed record of such phenomena as marine transgression 

and regression, cyclic sedimentation, marine-continental litho- and biofacies relationships, diastem and unconformities, and a spectrum of paleoenvironmental and 

paleoecological data. The Grand Canyon is a field laboratory of study in which 

McKee has contributed a wealth of ideas supported by extensive field observational 

and laboratory data for generations of students to come.

To appreciate the scope of McKee's program as a prelude and a foundation for 

the Supai study and to furnish the reader with background references to definitive 

contributions of this exceptional stratigraphic column, the following list gives 

McKee's major works in stratigraphic order from top to bottom. With this list, 

reference should be made to the generalized graphic section of the Grand Canyon on 

the opposite (facing) page. Fossil groups represented on the diagram call attention to 

detailed reports by specialists that are included in each monograph; McKee did the 

paleontology for the early studies. Innumerable other published works of McKee's 

studies related to the Grand Canyon are not included in this summary.

McKee, E. D., 1954, Stratigraphy and history of the Moenkopi Formation of 

Triassic age: Geological Society of America Memoir 61,133 p.

____1938, The environment and history of the Toroweap and Kaibab Formations of northern Arizona and southern Utah: Carnegie Institution of 

Washington Publication 492, 268 p.

_1934, The Coconino Sandstone its history and origin: Carnegie Institution of Washington Publication 440, p. 77-115,14 pis.

_The Supai Group of Grand Canyon: Present Professional Paper.

McKee, E. D., and Gutschick, R. C, 1969, History of the Redwall Limestone of 

northern Arizona: Geological Society of America Memoir 114, 726 p.

McKee, E. D., and Resser, C. E., 1945, Cambrian history of the Grand Canyon 

region; Pt. 1. Stratigraphy and ecology of the Grand Canyon Cambrian; 

Pt. 2. Cambrian fossils of the Grand Canyon: Carnegie Institution of Washington Publication 563, 232 p.

McKee, E. D., 1969, Stratified rocks of the Grand Canyon A history of stratigraphic investigation in the Grand Canyon region, in The Colorado River 

region and John Wesley Powell: U.S. Geological Survey Professional Paper 

669-B, p. 23-58.

Not present on the above list are detailed reports on the Devonian Temple Butte 

Limestone and the Permian Hermit Shale. Observations were made on the Devonian
THE SUPAI GROUP OF GRAND CANYON

from the first days that McKee stepped foot in the Grand Canyon as park naturalist, 

back in 1929; he has since examined it and measured sections in many places. As 

regards the Hermit Shale, McKee assisted Dr. David White in the canyon during 

some of his classic studies of that formation in 1928.

Accessibility to the rocks in the Grand Canyon is reflected in the chronology of 

McKee's reports. Early studies relate to rocks at or near the rim, followed by studies 

from river level up (Carnegie Institution boat trip in 1937), and lastly, studies of 

rocks that are least accessible, in the middle of the chasm walls.

Basic geologic research established from carefully made field observations and 

library and laboratory investigations all done with scientific zeal and precision is 

the lifeblood of our applied science. The present report on the Supai Group is an 

outstanding example of this ideal by a master field geologist and laboratory investigator. It represents an exhaustive treatment of the geologic history of these rocks 

with emphasis on the sedimentation, stratigraphy, paleontology, and paleogeography. McKee in his classical style presents a wide array of basic geologic data from 

which he makes logical interpretation of the genesis of this red bed-carbonate facies 

sequence. It fills a major gap between the Mississippian Redwall history and Permian 

Coconino-Toroweap-Kaibab history of the Grand Canyon area.

Proximity of the type area and type sections to the Havasupai Indian village of 

Supai in the bottom of Havasu (Cataract) Canyon and the affection McKee has for the 

gentle agrarian sun people (Supai) who live there account for the names of three of the 

four formations of the Supai Group and also for the pictures of Supai baskets used as 

chapter headings in this book. C. E. Dutton's (1882, U.S. Geological Survey 

Monograph 2) reference to the "Esplanade" as the majestic red bed-veneered expanse 

on top of the Supai Group is a natural designation for the uppermost formation.

Obstacles in most geologic studies of red-bed sequences are: (1) lack of traceable 

continuity of strata for correlation purposes, and (2) apparent absence of fossil faunas 

and floras from which to establish a detailed time-zonation framework. For Supai 

research, perceptive field observation proved successful in making possible recognition of key conglomerate beds and erosional unconformity surfaces for correlation 

of strata, the discovery of marine faunas that yielded close resolution of a succession 

of time units for zonation, and identification of marine and continental lithologic 

and faunal facies for interpretation of the environments of deposition. These are all 

hallmarks of the principles and models which McKee established through his earlier 

studies in the Grand Canyon.

A major contribution of this professional paper is the sedimentological analysis 

of the Supai Group. McKee has pioneered the study of sedimentary structures by 

field comparison of ancient examples in rocks with supposed modern analogs. For 

more than the past two decades, he has followed such field observations with laboratory experiments in order to understand the conditions and variable parameters 

critical for replication of each structure or combination of structures. This experience 

and information has been applied to the Supai Group. Large quantities of field data 

and collections were analyzed for the sedimentary attributes from 32 stratigraphic 

sections measured in an area of approximately 15,000 square miles in which the 

Supai Group varies in thickness from 700 to more than 1,000 feet.

The chapters of this book have been organized with excellent graphic illustrations 

for comparison of the quantitative data with geographic units and to similar examples 

in modern environments. Much of the analysis of the raw sedimentological data, 

interpretation of its environmental significance, and organization of the text was 

done by McKee during a lengthy siege of illness. In effect, adversity accelerated the 

completion of this professional paper even though the initial fieldwork started in 

1936. Indeed, such a course illustrates that geological reports from extensive field 

data take a long time to complete.
FOREWORD XI

Contributions from paleontologists and other specialists are critical to and 

enhance the report with their resolution of dating and facies interpretation. The 

accounts of clay mineralogy, petrography, and stable isotope analysis have greatly 

sharpened the interpretation of environments both for the Supai Group and for 

pre-Supai history. Most useful fossils for recognition of geologic time and facies are 

the brachiopods, corals, small foraminifera and fusulinids and, to a smaller extent, 

the molluscs and other less common forms. Discovery by Billingsley of pre-Supai 

drainage valleys on the Redwall Limestone surface fits the regional paleogeography 

of pre-Chester age epeirogenesis and the Chester continental-marine sedimentary 

pattern of the northern and middle Rocky Mountains and eastern Great Basin to the 

north.

This foreword is a tribute to the wisdom, foresight, and energy of Edwin D. 

McKee and the outstanding contributions to Grand Canyon geology by the U.S. 

Geological Survey for more than a century. McKee follows in the footsteps and 

tradition of Marcou, Newberry, Powell, Gilbert, Marvine, Walcott, Dutton, Darton, 

Noble, and White. Students of earth history, the geological profession, and the 

public are richer for knowledge of the natural wonders and creation of the Grand 

Canyon, and we express our gratitude for the progress of geological science to these 

men.

Research Geologist

Department of Earth Sciences

University of Notre Dame

Notre Dame, Indiana 46556

THE SUPAI GROUP OF GRAND CANYON

INTRODUCTION

Chapter A 

By EDWIN D. McKEE

Contents

Scope of study ..............

Historical review ... ...,...,.,...

Analysis of depositional environments 

Method of study . . . .......

Terminology for principal rocks .....

Acknowledgments ..........

References cited .................

Page

3

3

5

8

10

11

13
THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURE A1 . Map showing localities of measured sections and principal lines of sections ........... 6

A2-A8. Profiles of measured sections:

A2. A-A' ..... ..... ....... ..................................... 8

A3. B-B' ..... ............................... . . ,,.,...... 10

A4. C-O ........................................................... 12

A5. D-D' .................................... ................... 14

A6. Upper E-E'-E" ....................... .......................... 15

A7. Lower E-E'-E" ................................................ 16

A8. F-F' .. .... ............................................ 18

Table

Page

TABLE Al Classifications of Carboniferous-Permian strata of Grand Canyon, Ariz. .............. 4
INTRODUCTION

SCOPE OF STUDY

The present study of the Supai Group dates back to 1936. 

At that time the writer, while engaged in stratigraphic 

work on the Kaibab Limestone and Toroweap Formation 

and, later on the Cambrian strata of Grand Canyon, under 

the auspices of the Carnegie Institution of Washington, 

took the opportunity to examine red beds and to measure 

some Supai sections. As a result, the general character of 

the rocks and certain regional changes became familiar 

(McKee, 1937, p. 341; 1938, p. 358).

It was not until the late 1930's, when systematic work on 

a statistical study of cross-strata dip directions was undertaken (McKee, 1940a), that the trends and the complexity 

of the Supai problem began to be apparent. Also, at about 

that time, discovery of an assemblage of invertebrate 

fossils in the basal slope unit (now Watahomigi Formation) 

of the Supai at Toroweap Valley and at Parashant Canyon 

stimulated interest in the age of the strata. Fossil collections sent to Dr. James Williams of the U.S. Geological 

Survey were determined to be not of Permian age as generally supposed at that time, but of Early Pennsylvanian age.

The "Stratigraphy of the Supai Formation and Hermit 

Shale of Grand Canyon" was made an official project of the 

U.S. Geological Survey in 1959, with E. D. McKee as project chief. A program of study was planned to get underway 

at that time and to be continued over a period of years, 

averaging about two months' study in the field each year. 

Meanwhile, chemical, mechanical, and other analyses of 

selected rock samples were made in the Denver laboratories 

and fossil determinations were obtained from specialists 

in Washington, D.C., as various stratigraphic sections 

were being completed.

HISTORICAL REVIEW

The earliest reference by a geologist to rocks now called 

the Supai Group was by Jules Marcou (1856) who, as a 

member of an exploration party for the U.S. Pacific Railroad under Lt. A. W. Whipple, traversed northern Arizona in 1853-54. Marcou did not see Grand Canyon, but 

examined several of its formations where they crop out at 

Partridge and Cedar Creeks, to the south. Marcou referred 

to "carboniferous sandstones the equivalents of the coal 

measures," which apparently included both the Coconino 

Sandstone and Supai, beneath the "magnesian limestone" 

[Kaibab] and above the "mountain limestone" [Redwall].

Supai rocks in Grand Canyon were first examined and 

described by J. S. Newberry (1861, p. 42, 59, 63) who 

referred to them as "blood red calcareous sandstones 

and shales, which have an aggregate thickness of nearly 

500 feet." They were reported to underlie cross-stratified

sandstones and to be above Lower Carboniferous(?) limestone. Newberry found no fossils in them, but described 

the presence of gypsum and a stratum of cream-colored 

limestone.

Little mention of the Supai rocks was made by J. W. 

Powell (1875) in his classic report on the geology of Grand 

Canyon, based on the river expeditions of 1869 and 

1871-72. The Supai was referred to only as "rocks of 

Carboniferous Age" (Powell, 1875, p. 212) and "Carboniferous formation" [including Kaibab and others] (p. 180). 

It was described as "beds of bright red sandstones, 

weathered to form shelves *** but in many places 

[broken] down in steep slopes" (p. 195).

The first formal name applied to the Supai strata (and 

the overlying Paleozoic formations) of the Grand Canyon 

was Aubrey Group (see chapter C for formal abandonment of this name). This name was given by G. K. Gilbert 

(table Al) during the U.S. Geographic and Geologic Survey west of the 100th Meridian (Gilbert, 1875, p. 176-185) 

and was derived from exposures at Aubrey Cliffs bordering 

the Aubrey Valley south of Grand Canyon. Only the 

uppermost part of the Supai Group (McKee, 1975) is exposed at this locality; most of the red beds exposed in 

Aubrey Cliffs are Hermit Shale.

Subsequently, in a report on the Paleozoic groups of 

Kanab Canyon, on the north side of Grand Canyon, C. D. 

Walcott (1880, p. 221-225) subdivided the Aubrey1 Group 

into an upper Aubrey (consisting of the Kaibab Limestone 

and Toroweap Formation) and a lower Aubrey (Coconino 

Sandstone, Hermit Shale, Supai Group of McKee, 1975, in 

part) (table Al). Below the lower Aubrey Group is the 

"Red Wall Limestone"; together the three groups are referred to the "Carboniferous." They are described by 

Walcott (1880, p. 224) as having a fauna "of the coalmeasure type, except near the base [where there is] a much 

larger proportion of a Lower Carboniferous character." 

Based on descriptions and thicknesses given by Walcott, 

much or most of the Supai was included in the lower 

Aubrey.

The term lower Aubrey Group, as applied by C. E. 

Dutton in his monographic treatment of the Tertiary history 

of Grand Canyon (1882), differed considerably from the 

stratigraphic units and boundaries as used in adjacent 

areas by other geologists of the time. The term Aubrey 

Group was used by Dutton at Toroweap Valley (p. 89) 

(table Al, col. 3) for strata of the "outer" canyon, "from 

the summit [rim] to the plain below [Esplanade]." His upper Aubrey therefore consisted of the Kaibab, Toroweap, 

and Coconino of present usage, but his lower Aubrey was 

restricted to the Hermit Shale. This usage is shown in Dutton's figure 1, profile "at the foot of the Toroweap Valley," 

and in his statement (p. 88): "The walls of the inner gorge 

have at the summit about 325 feet of hard sandstone of a

'This name was incorrectly spelled "Aubry" throughout the report.
THE SUPAI GROUP OF GRAND CANYON

brown red color. Below the sandstone are about 1,800 feet 

of impure limestone in layers of the most massive description." From this statement, it seems certain that Dutton 

included all of the present Supai Group in his "Red Wall 

group," and only the Hermit Shale was assigned to the 

lower Aubrey.

Further confusion (table Al, col. 4) in the stratigraphic 

classification as used by Dutton (1882) is apparent in his 

Plate XXIV, "Key to the Panorama from Point Sublime 

Looking South." In this precise, detailed drawing, the unit 

marked 4 is labelled "Lower Aubrey sandstones"; it consists of the Hermit Shale, and all of the Supai Group, 

except for the lowest slope unit (Watahomigi Formation of 

the present publication). Unit number 5 in the "Panorama" 

is labelled the "Upper Red Wall sandstone" and is comprised of the Watahomigi only. Almost certainly the 

discrepancy (table Al) between the rock assignments in the 

lower Aubrey Group in Dutton's "Panorama from Point 

Sublime" and his "Toroweap Valley" description and 

profile (fig. 1) is the result of miscorrelation resulting from 

major differences in topographic expression of the same 

stratigraphic units in the two areas.

After a reconnaissance study by N. H. Darton (1910, 

p. 25) in parts of northwestern New Mexico and northern 

Arizona, he recommended that rocks of the Aubrey Group 

be separated into formations and that these be given formal status. In proposing the "Supai formation" Darton 

stated: "The red sandstones and shales constituting the 

lower portion of the Aubrey group in northern Arizona 

form a definite stratigraphic unit over a wide area. Accordingly, I propose that they be designated the Supai 

formation, from the Supai village on Cataract Creek, 

where they are very conspicuously exposed." Thus, 

Havasu (Cataract) Canyon, a tributary of Grand Canyon 

on its south side, is the type locality of the formation. It is 

overlain by the Coconino Sandstone and underlain by the 

Redwall Limestone (table Al, col. 5).

Because the "Supai formation" as originally defined by 

Darton included at its top a sequence of red shaly siltstones, 

separated from the main body of strata by an erosional 

unconformity, these upper beds were removed from the 

Supai by Noble (1922, p. 64) and made a separate formation called the "Hermit Shale" (table Al, col. 6). At the 

same time, Noble further redefined the Supai by adding to

TABLE A1.— Classifications of Carboniferous-Permian strata of Grand Canyon, Ariz.

Gilbert 

(1875, fig. 82)

Aubrey

Group

Red Wall 

Limestone 

Group

Walcott 

(1880, p. 222)

Upper 

Aubry1

Group

Lower 

Aubry1

Group

Red Wall 

Limestone

Dutton 

(1882, pi. XXVIII; 

Point Sublime)

Upper 

Aubrey

Group

Lower 

Aubrey

Group

Red Wall 

Group

Reference

Dutton 

(1882, fig. 1; 

Toroweap Valley)

Upper 

Aubrey

Group

Lower 

Aubrey Group

Red Wall 

Group

Darton 

(1910, p. 25)

Kaibab

Limestone

Coconino 

Sandstone

Supai 

Formation

Redwall 

Limestone

Noble 

(1922, p. 60)

Kaibab

Limestone

Coconino 

Sandstone

Hermit 

Shale

Supai 

Formation

Redwall 

Limestone

Present 

study

Kaibab 

Limestone

Toroweap 

Formation

Coconino 

Sandstone

Hermit 

Shale

Esplanade 

Sandstone2

§" Wescogame 

(^ Formation

're Manakacha

Q.

Watahomigi

Formation

Pre-Supai 

sediment3

Redwall 

Limestone

c

03

F

£

c

ro

ro 

">~

c

O)

Age

Leonardian

-—.—„-— ? —--——„.

Wolfcampian

Virgilian

Des Moinesian(?)

Atokan

Morrowan

Chesterian

Mississippian

1 Spellmg used by Walcott.

2 Lower part replaced by Pakoon Limestone (McNair, 1951) in western Grand Canyon.

3 ln buried valleys.
INTRODUCTION

its base "about 25 feet of red sandy shale, purplish and 

gray limestone with red chert and reddish to buff calcareous sandstone of Pennsylvanian age that have heretofore 

been included in the Redwall limestone." The age of the 

"Supai formation" was believed to be Permian(?) and 

Pennsylvanian.

Following the detailed studies and the reclassification of 

the Supai by Noble, completed in 1922, work on rocks of 

this group in Grand Canyon was intermittent for the next 

three decades. The most notable contribution was a monographic study of the flora of the Hermit Shale by David 

White (1929); other publications were limited to a few 

scattered stratigraphic notes on plants by White (1927, 

1928), on fossil trackways by Gilmore (1927, 1928), and 

on stratigraphy and paleogeography by McKee (1938, 

1940a,b, 1947, 1951).

In the region south of Grand Canyon, several studies of 

the Supai and its lateral equivalents were made during the 

1940's. These were largely on stratigraphy, but included 

some paleontology and environmental interpretation 

(Huddle and Dobrovolny, 1945; Hughes, 1949, 1952; 

Winters, 1951, 1963; Jackson, 1951). Later investigations 

in the same region were by Lokke (1962), Brew (1965), 

Gerrard (1964), Peirce (1958, 1966), and Ross (1973).

The Supai and its correlatives in northwestern Grand 

Canyon and adjoining parts of Arizona, Nevada, and Utah 

did not receive much attention until the early 1950's when 

McNair (1951) proposed two new formations and reorganized the local stratigraphy. One of these formations, the 

Pakoon Limestone, is considered (in this report) to be a 

western equivalent of the lower part of the Esplanade 

Sandstone. For this reason and because much of the fossil 

evidence dating the upper part of the Supai comes from the 

Pakoon Limestone, it is included in sections of the northwestern Grand Canyon area even though not part of the 

Supai Group (figs. A2-A8).

The work of McNair was followed in the late 1950's and 

1960's by a series of stratigraphic studies north and west of 

Grand Canyon, some establishing zones and determining 

boundaries on the basis of fossils, others correlating rock 

units and unconformities between various areas (Steele, 

1959; Welsh, 1959; Bissell, 1962, 1969; Brill, 1963; Heath, 

1965; Langenheim and Langenheim, 1965; Cassity and 

Langenheim, 1966; Douglass, 1974).

During the 1960's, the Supai and related rocks in northwestern Grand Canyon and neighboring areas also were 

the subject of numerous local petrographic and lithologic 

investigations. Studies along the north side of the canyon, 

involving detailed mapping and lithologic correlation, 

were made by Sorauf (1962), Fisher (1962), and Billingsley 

(1970). Studies that were principally petrographic were 

made in adjoining parts of Nevada by Lumsden (1965), 

Heath, Lumsden, and Carozzi (1967), and Lumsden, Ledbetter, and Smith (1973).

In northeastern Arizona beyond the Grand Canyon, 

correlative strata of the Supai in the San Juan Basin received 

considerable attention, especially from the standpoint of 

stratigraphy, during the late 1950's and 1960's. Under the 

stimulus of petroleum exploration, a great proliferation of 

publications occurred at this time. Some of the important 

studies were by Merrill and Winer (1958), Wengerd and 

Matheny (1958), Peterson (1959), Baars (1962), and Peterson and Ohlen (1963). Studies of the gypsum deposits were 

recorded in Sears (1956) and O'Sullivan (1965).

Investigations of the Supai Group have by no means been 

limited to stratigraphic, petrographic, and faunal studies. 

One of the most thoroughly studied subjects has been the 

paleogeography as represented by the structural framework 

in which the Supai was formed. Determination of the constantly fluctuating land and sea relations, and delineation 

of positive elements, basins, and troughs, have been the 

subjects of many papers during the past several decades. 

Since 1949, 17 systems of tectonic elements, together with 

sets of proposed terms for paleogeographic units, have 

been published; they are summarized in table D2. Isopach, 

lithofacies, and paleogeographic maps of these features are 

many.

ANALYSIS OF DEPOSITIONAL 

ENVIRONMENTS

The ultimate aim in the current investigations of the 

stratigraphy and sedimentology of the Supai Group has 

been to interpret the various environments of deposition 

represented by its components. Because the rocks of four 

formations, with a range in age from Early Pennsylvanian 

into the Early Permian, and with a geographical distribution equal to the entire Grand Canyon area are under 

consideration, a large variety of environments represented 

by many lithologic facies is to be expected.

The facies of the Supai Group clearly range from continental to normal marine and include a wide variety of 

intermediate types. End members in this sequence of facies 

are, in general, easy to recognize. Many of the siltstones 

and mudstones at one extreme are clearly of continental 

origin as indicated by the presence of land plants and such 

diagnostic minor structures as shrinkage cracks and rain 

pits. At the other extreme, limestones of several forms 

peloidal, bioclastic, accretal, and micritic are recognized 

as definitely marine, especially where they contain such 

fossils as corals, brachiopods, and crinoids. Differences in 

the size and shape of clastic grains are attributed to various 

degrees of current energy.

Between the end members are many facies, the exact 

natures of which are difficult to establish either in terms of 

water salinity, of geographic position, or of transport and
THE SUPAI GROUP OF GRAND CANYON

depositional processes. Some inferences as to salinity 

can be made on the basis of composition. Rocks such as 

gypsum and dolostone are indicators of depositional environment. Virtually all of the sandstones and many of the 

siltstones, however, contain no diagnostic fossils or any 

distinctive mineral or rock constituents that give evidence 

of genesis. Primary structures must be resorted to as the 

only reliable type of evidence available for interpreting the 

genesis of many parts of the Supai.

Numerous approaches have been used in this analysis of 

depositional environments. Even though conclusive evidence of genesis is not furnished by any single study, definite trends of various kinds collectively point to the most 

probable interpretations. Accordingly, the first and 

primary consideration has been a reconstruction of paleogeography to establish a framework on which all accumulations of data could be organized. By the development of 

isopach maps both for the area under study and also for a 

statewide region of which this area is a part, the basic 

relationships between negative and positive areas have 

been established. Furthermore, by detailed analysis of 

widespread erosional surfaces, using key conglomerate

36° -

FIGURE A1.—Locality map of Grand Canyon region, Arizona, showing positions (solid circles) of measured stratigraphic sections (1-35) and principal lines of sections (A-A' to F-F') referred to throughout text. Arrow and miles indicate direction and distance to actual locality of section.

EXPLANATION 

MEASURED SECTIONS

Number 

la

Ib

Name 

House Rock Canyon

Location/Description 

Partial section; basal conglomerate of Esplanade Sandstone at mile 16.5 in Marble Canyon, west wall

Near mile 22, Marble Canyon Partial section; upper part of section measured on west side of Colorado River near mile 23; basal conglomerate measured on east side of River at mile 22

Twentynine Mile Canyon 

Eminence Fault 

Blue Spring

Along northeast wall at Marble Canyon (section progresses up Twentynine Mile Canyon) 

Along east side of Eminence Fault in Marble Canyon, east wall 

Along the trail to Blue Spring
INTRODUCTION

4a

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21a

21b

22a

22b

23

24

25

26

27

28

29

30a

30b

30c

31

32

PB

34

35

Horsetrail Canyon

Bunker Trail

Grandview Trail

Kaibab Trail, south

Kaibab Trail, north

Hermit Trail

Bass Trail

Shinumo Trail

Thunder River Trail

Topocoba Trail

Havasu Canyon

National Canyon

Kanab Canyon

S B Canyon

Tuckup Canyon

Blue Mountain Canyon

Prospect Valley

Toroweap Valley

do.

Whitmore Wash

do.

Parashant Canyon

Andrus Canyon

Twin Springs Canyon

Guano Cave

Snap Canyon

Pigeon Wash

Grand Gulch Mine

Hidden Canyon

do.

do.

Iceberg Canyon

Seligman

Separation Canyon

Hindu Canyon

At Little Colorado River, 0.5 mile downstream from Waterhole Canyon 

Along west side of Bunker Trail (locally called Tanner Trail) below Lipan Point 

Along Grandview Trail on west side of main ridge; 1 mile south of Horseshoe Mesa 

Along ridge extending north from Yaki Point

Slope and cliff units of Esplanade Sandstone measured on north side of Roaring Springs Canyon; lower 

part of group measured on south side

Measurement begins south of major slump area crossing trail on east side of canyon 

On west side of Bass Canyon east of Mount Huethawali

Measured northeast of trail in Muav Canyon, western part of Shinumo Amphitheater 

Measured in Fishtail Canyon about 3 miles from Thunder River Trail

Partial section; along south side of trail, 1 mile west of Topocoba Hilltop; lower part of Supai not 

measured

Watahomigi Formation measured on west side of canyon at Navajo Falls; upper part of group measured along Apache Trail, northeast of Supai Village

In National Canyon, Hualapai Indian Reservation. Watahomigi measured on west side above the gorge 

formed by the Redwall Limestone; from Manakacha to Esplanade, measured on east side; Esplanade 

measured on west side of canyon

On west side of Kanab Canyon, 2 miles north of Colorado River

In S B Canyon (Hundred and Fifty Mile Canyon)

Upper part measured in Cottonwood Canyon; lower part in Tuckup Canyon

In Blue Mountain Canyon, southwest side, T. 26 N., R. 9 W.; upper part measured on west side of 

Tower of Babylon

On east side of Prospect Valley, 6 miles south of Colorado River

Measured south of Toroweap Point, east of lava flows

Partial section; on west side of Toroweap Valley (measured at foot of valley to record fossil horizons)

On east side near the mouth of Whitmore Wash (lower part measured in narrow canyon normal to the 

wash)

Partial section; complete Esplanade section on east side of Whitmore Wash; measured north of section 

22a, between major basalt cascades

East of Shivwits Plateau

Upper part measured on canyon wall about 2 miles southeast of Grassy Mountain; lower part on 

southwest side of canyon, west of fault zone about 9 miles southeast of Grassy Mountain

Lower part measured on west side of canyon; Esplanade Sandstone measured on east side 

Measured at tram to Guano Cave (also called Bat Cave) on south side of Colorado River 

Grand Wash Cliffs; measured in Snap Canyon about 5 miles south of Grand Gulch Mine 

On north side of Pigeon Wash, Grand Wash Cliffs 

Partial section; measured northeast of mine

Partial section; measured 3 miles south of Hidden Canyon; together with sections 30b and 30c, makes a 

complete section of Supai strata

Partial section; main part of Hidden Canyon section

Partial section; measured on east side of Jump Canyon, 0.5 mile from junction with Hidden Canyon

Measured on east side; regional dip 45°

Partial section; on Aubrey Cliffs, 4 miles west of Seligman

South side of Picacho Butte

Measured on south side of Colorado River at Separation Canyon east of Spencer Canyon

In eastern end of Hindu Canyon, south of Bridge Canyon, on small mesa at approximately sec. 24, 

T. 27 N., R. 12 E. and sec. 19, T. 27 N., R. 11 W.
THE SUPAI GROUP OF GRAND CANYON

A

West

HAVASU TOPOCOBA 

CANYON TRAIL 

(14) (13) 

5.5 miles ,^ 22 miles

KAIBAB TRAIL, 

HERMIT TRAIL SOUTH 

(9) (7) 

, 7.5 miles ,

Redwall Limestone

FIGURE A2.—Stratigraphic profiles of Supai Group along line A-A' (fig. A1)

beds for correlation, the locations of principal unconformities are established, thus subdividing the Supai Group in 

time as well as space.

Succeeding chapters of this volume are organized principally on the basis of lithology. For each rock type, consideration is given to such features as texture, structure, 

geometry, and fossils. This publication has been organized 

to permit easy comparisons, using tables, charts, and 

diagrams of various attributes such as grain size frequency, 

distribution of grain forms, direction of current movement, shape and percent of various types of grains, that 

lend themselves to quantitative measurement. Thus, it 

should be possible to directly compare these attributes

within the principal geographic units east, central, and 

western parts of the area and, finally, between the ancient 

strata of the Supai and their various possible analogs as 

represented in selected models of modern environments.

METHOD OF STUDY

Plans for investigation of the Supai Group in Grand 

Canyon, like those for earlier studies of Paleozoic strata in 

that area, were designed to take full advantage of the excellent and nearly continuous exposures of the stratigraphic 

record. By using a network of carefully measured detailed
INTRODUCTION

7.5 miles

GRANDVIEW

TRAIL

(6)

BUNKER

TRAIL

(5)

A' 

East

BLUE

SPRING

(4)

8 miles 11 miles

EXPLANATION

Sandstone 

Flat-bedded

Cross-stratified 

Siltstone 

Mudstone 

Limestone 

Dolostone 

Conglomerate 

Erosion surface

XS Cross-strata

Cone. Concealed

L Land plants

Wb Worm boring (trail)

Sc Shrinkage cracks

t Vertebrate tracks

J Jasper

O Stromatolites

f Fossils, invertebrate

— Atokan-Morrowan boundary

Sandstone, dominant grain size (Wentworth scale)

VF Very fine grained

F Fine-grained

M Medium-grained

in Grand Canyon region, Arizona. Horizontal distance in miles is not to scale.

sections, the trends in lithologic and faunal change were 

determined and traced across an area approximately 150 mi 

from east to west and 100 mi from north to south (fig. Al). 

Thirty-five sections of the Supai, distributed along the 

lines A-A' C-C', andF-F' in a general east-west direction, 

and B-B', D-D', and £-£'-£" in a north-south direction 

(figs. A2-A8) were measured and described in detail. 

These sections record the principal lithologic units 

recognized in the field and give the all-important vertical 

dimension to the study. Various modifications of these 

stratigraphic columns were used as the bases on which to 

record, in three dimensions, such data as the distribution 

of fossils, the size and sorting of sand grains, directional

vectors of cross-bedding, calcium-magnesium ratios, and 

various other features of each formation. In brief, the 

vertical sections became responsible for conclusions concerning the trends and interpretation of the geologic attributes of each formation.

In addition to field studies, in many of which a statistical 

approach was used, numerous laboratory investigations 

were undertaken. These included the petrographic examination of 970 thin sections, the study of more than 1,000 

insoluble-residue samples, the compiling and interpreting 

of 524 calcium-magnesium ratios, and the plotting of 272 

mechanical analyses (grain determinations by sieving) of 

sandstones.
10

FEET 

900

800

700

600

500

400

300

200

100

50

0

B

North

HOUSE

ROCK

CANYON

NEAR 

MILE 22, 

MARBLE 

CANYON

4.5 miles 7 miles

THE SUPAI GROUP OF GRAND CANYON

TWENTYNINE MILE EMINENCE 

CANYON FAULT 

(2) (3) 

9 miles 21.5 miles

BLUE

SPRING

(4)

3.5 miles

B'

South

HORSETRAIL

CANYON

(4a)

i; i ; i Redwall Limestone 

EXPLANATION

Sandstone 

Flat-bedded

Cross-stratified 

Siltstone 

Mudstone

Limestone 

Dolostone 

Conglomerate 

Erosion surface

XS Cross-strata 

Cone. Concealed 

J Jasper 

O Stromatolites 

f Fossils, invertebrate 

^ Atokan-Morrowan boundary 

Sandstone, dominant grain size (Wentworth scale) 

VF Very fine grained 

F Fine-grained 

M Medium-grained

FIGURE A3.-Stratigraphic profiles of Supai Group along line 8-8' (fig. A1) in Grand Canyon region, Arizona. Horizontal distance in miles is not to scale.

TERMINOLOGY FOR 

PRINCIPAL ROCKS

In general, standard terms for the basic rock types are 

used throughout this publication, but a few words in which 

usage is controversial or meaning is somewhat ambiguous 

are defined here for the sake of clarity.

For all detrital rocks the size grade scale of Wentworth 

(Wentworth, 1922) is used throughout, both for sediment 

(disaggregated grains) and for sedimentary rocks (consolidated sediment). Thus, in the largest size, four grades 

of gravel, ranging from 2 mm upward, are recognized; in

the intermediate or sand size, five grades ranging from 

1/16 to 2 mm are recognized, and in the smallest size, consisting of silt and clay, two grades are recognized.

The name "shale" has been used by geologists in three 

different senses, referring to (1) fine grain size, (2) splitting 

property or fissility of rock, and (3) composition (argillaceous character). The term "shale" is here restricted to the 

second use: mudstone with splitting properties. Wherever 

it is desirable to distinguish mineralogic composition, the 

terms "argillaceous" or "carbonate" are used in conjunction 

with mudstone. Where the grain size has been determined, 

the rock is termed either "siltstone" (1/16-1/256 mm) or 

"claystone" (< 1/256 mm), or "mudstone" if both occur in
INTRODUCTION 11

roughly equal proportions.

For carbonate rocks containing large proportions of 

quartz grains (as much as 50 percent), the term 

"arenaceous" is used to indicate the presence of quartz 

grains; the term "sandy" is used to indicate the size class, as 

opposed to "silty."

The term "limestone" designates all rocks dominantly 

composed of CaCO3 ; rocks with the CO3 radical, including 

both limestone and dolostone, are generally referred to as 

"carbonate rocks." The mineral (Ca, Mg) CO3 is referred 

to as "dolomite"; the rock formed of this mineral is termed 

"dolostone."

Limestone with very fine (aphanitic) texture is referred 

to as a "carbonate mudstone" or "micrite."

Sandstone with a high content of calcium carbonate (but 

less than 50 percent) is termed "calcareous sandstone," not 

limy sandstone.

Carbonate rocks for which Ca-Mg ratios have been determined are classed as follows:

Molal ratio 

Dolostone ......................... 1.0 - 1.20

Calcitic dolostone .................. 1.20- 2.85

Dolomitic limestone ................ 2.85- 17.67

Magnesian limestone ................ 17.67- 36.19

Limestone ......................... 36.19-100.00

With the exception of the size grade scale, all measurements were made in inches, feet, or miles and are so 

reported. The following English-metric conversion scales 

are given for the convenience of the reader. They are for 

visual comparison only and do not represent actual units 

of measurement.

0 0.5 1 2 3 Inches

6 Centimeters

10 Feet

3 Meters

40 Miles

0 5 10 20 30 40 Kilometers

Comparative English and metric scales

Conversion units from English to metric are as follows: 

1 in. =2.54 cm; 1 ft = 0.3048 m; 1 mi = 1.609 km; 1 mi2 

= 2.6 km2 .

ACKNOWLEDGMENTS

Field investigations of the Supai Group in Grand Canyon, carried on intermittently (1-3 months per year) over 

a period of about 14 years, were made with the assistance

of numerous geologists. I wish to gratefully acknowledge 

the help of the following, each of whom accompanied me 

during one or more field seasons: Thomas A. Sterrett, 

James Mytton, Claude H. Baker, Donald C. Koenig, Joseph M. Barrett, John McDowell, Willard McCracken, and 

Kenneth Gardner. Thanks are also due numerous geologists not with the U.S. Geological Survey wrto contributed 

much help in the field on a voluntary basis. They are as 

follows: David Niev, William Breed, Carlos Renaldi, Manfred Hobbler, Kenneth Hamblin, and George Billingsley.

Laboratory work, supplementing the field investigations 

included preparation of mechanical analyses by sieving, 

insoluble-residue determinations and calcium-magnesium 

ratio analyses, all by Robert Gantner of the U.S. Geological Survey's Denver sedimentation laboratory. Compilation of textural data for sandstones, and determination of 

stratigraphic and distribution patterns for lithologic types 

were largely by Suzanne Rittenhouse and Kenneth Gardner. 

Thin-section studies and microfacies analyses of carbonate 

rocks were by Walter Pierce. Credit also is due Walter 

Pierce for compiling data on insoluble-residue analyses. 

The series of histograms in chapter M, illustrating the 

trends of these analyses, was prepared by James Gude III.

The determination of clay minerals, the study of their 

distribution patterns, and their interpretation were by 

Phoebe Hauff, who is largely responsible for chapter O. 

Assistance in the preparation of the clay samples for analysis was given by Walter Pierce and Kenneth Gardner.

Most figures were prepared from field sketches and 

measurements. Fossil-distribution charts and paleogeographic maps were drafted by Curt Mast; the cover portraying the type section of the Supai Group, the fence 

diagrams of each formation, and various drawings of unconformities and lithologic relations were by William 

Chesser. Profiles of measured stratigraphic sections were 

by Sarah Andrews; most other illustrations, including 

charts of the key conglomerate beds, of cross-bedding 

types and of lithologic distribution were drafted by Bruce 

Towsner, Leslie Anderson, Tony Vaccavello, and Robert 

Cull of the Boulder Vocational Technological Center.

Acknowledgment of much assistance and helpful suggestions in the preparation and editing of the manuscript is 

extended to Diane C. Schnabel, Paula Hansley, and Sigrid 

Asher-Bolinder of the U.S. Geological Survey. For a careful and accurate job of preparing the descriptions of 

"Measured Sections" that are basic to the study, sincere 

thanks are given Margery Cater, and for manuscript preparation in the early stages much credit is due Shirley Person, Helen Colburn, and Hyla Strickland of the U.S. Geological Survey.

Faunal determinations for each of the fossil groups represented in the Supai and related pre-Supai strata were by 

specialists as follows:
12 THE SUPAI GROUP OF GRAND CANYON

FEET 

1000

900 -

700 - 

600

500

400

300

200

100

50

0

West

WHITMORE

WASH

(22)

12 miles

PROSPECT NATIONAL HAVASU TOPOCOBA

VALLEY CANYON CANYON TRAIL

(20) (15) (14) (13)

12 miles , 12 miles , 5.5 miles , 11.5 miles

Hermit 

Shale

feg-gy Esplanade 

Sandstone

Redwall Limestone

Small foraminifers ...... L. G. Henbest, retired.

Bernard Mamet, University of

Montreal. 

Endothyrids ........... Betty Skipp, USGS

(U.S. Geological Survey). 

Fusulinids ............. Raymond C. Douglass,

USGS. 

Corals ................ W. J. Sando, USGS.

Bryozoans ............. Helen Duncan, USGS.

Brachiopods ........... Mackenzie Gordon, Jr.,

USGS.

R. E. Grant, USGS. 

Gastropods ............ E. L. Yochelson, USGS.

Pelecypods ............ John Pojeta, Jr., USGS.

Conodonts ............ John W. Huddle, USGS.

Fish ................... David H. Dunkle, USGS.

Two of these paleontologists, Sando and Douglass, visited 

critical fossil localities in the field; most of the paleontoloFICURE A4.—Stratigraphic profiles of Supai Croup along line C-C' (fig. A1)

gists also furnished valuable information on ecology and 

age determination for the specimens examined. Sincere 

thanks are extended to all of them for their assistance.

Chapter F, entitled "Biostratigraphy of the Watahomigi 

Formation," has been prepared by Mackenzie Gordon, Jr., 

based on collections made during fieldwork on the Supai 

Group. This study represents a detailed analysis of the 

megascopic invertebrate faunas of the Watahomigi, a 

Stratigraphic analysis of their distribution patterns, and a 

discussion of broad correlation problems.

Chapter G on pre-Supai buried valleys is a description 

and discussion by George Billingsley and E. D. McKee of a 

part of the Stratigraphic record immediately preceding and 

leading up to the beginning of Watahomigi history. It is 

based on the discovery by Billingsley of sediment-filled 

valleys within the Redwall and beneath the Supai in parts 

of western Grand Canyon.
INTRODUCTION 13

BASS KAIBAB TRAIL, 

TRAIL NORTH 

(10) (8) 

19.5 miles 17.5

C'

East

EMINENCE 

FAULT 

(3) 

miles ^

Hermit Shale

EXPLANATION

Sandstone 

Flat-bedded

Cross-stratified

F-H^q Siltstone

hE>f:=jl Mudstone

[\ i | 11| Limestone

F=v?S Conglomerate

*~*^~^ Erosion surface

XS Cross-strata

Cone. Concealed

L Land plants

Wb Worm boring (trail)

Sc Shrinkage cracks

rm Ripple marks

rp Rain pits

R Rivularites sp.

J Jasper

f Fossils, invertebrate

^ Atokan-Morrowan boundary

Sandstone, dominant grain size

	(Wentworth scale) 

VF Very fine grained

F Fine-grained

M Medium-grained

in Grand Canyon region, Arizona. Horizontal distance in miles is not to scale.

REFERENCES CITED

Baars, D. L., 1962, Permian system of Colorado Plateau: American 

Association of Petroleum Geologists Bulletin, v. 46, no. 2, p. 149-218.

Billingsley, G. H., Jr., 1970, General geology of Tuckup Canyon, central 

Grand Canyon, Mohave County, Arizona: Northern Arizona University, M.S. thesis, 115 p.

Bissell, H. J., 1962, Pennsylvanian and Permian rocks of Cordilleran 

area, in Pennsylvanian System in the United States A symposium: 

American Association of Petroleum Geologists, p. 188-263.

____1969, Permian and Lower Triassic transition from shelf to basin 

(Grand Canyon, Arizona to Spring Mountains, Nevada), in Geology 

and natural history of the Grand Canyon region: Four Corners Geological Society Guidebook, p. 135-169.

Brew, D. C., 1965, Stratigraphy of the Naco Formation (Pennsylvanian) 

in central Arizona: Cornell University, Ph. D. thesis, 230 p.

Brill, K. G., Jr., 1963, Permo-Pennsylvanian stratigraphy of western 

Colorado plateau and eastern Great Basin regions: Geological Society of America Bulletin, v. 74, no. 3, p. 307-330.

Cassity, P. E., and Langenheim, R. L., Jr., 1966, Pennsylvanian and 

Permian fusulinids of the Bird Spring Group from Arrow Canyon, 

Clark County, Nevada: Journal of Paleontology, v. 40, no. 4, 

p. 931-968.

Darton, N. H., 1910, A reconnaissance of parts of northwestern New 

Mexico and northern Arizona: U.S. Geological Survey Bulletin 435, 

88 p.

Douglass, R. C., 1974, Fusulinids in the Basin and Range province in 

California, Nevada, and Utah: Journal of Paleontology, v. 48, no. 4, 

p. 846-853.

Dutton, C. E., 1882, Tertiary history of the Grand Canyon district: 

U.S. Geological Survey Monograph 2, 264 p.

Fisher, W. L., 1962, Upper Paleozoic and Lower Mesozoic stratigraphy 

of Parashant and Andrus Canyons, Mohave County, northwestern 

Arizona: Kansas University, Ph. D. thesis, 345 p.

Gerrard, T. A., 1964, Environment studies of the Fort Apache Member, 

Supai Formation (Permian), east-central Arizona: Arizona University, Ph. D. thesis, 187 p.

Gilbert, G. K., 1875, Report on the geology of portions of Nevada, Utah, 

California, and Arizona, examined in the years 1871, 1872, and 

1873: U.S. Geographical and Geological Surveys West of the 100th 

Meridian (Wheeler), v. 3, p. 17-187.
14 THE SUPAI GROUP OF GRAND CANYON

FEET 

1100 i—

1000

900

800

700

600

500

400

300

200

100

50

0

D

Northwest

ICEBERG 

CANYON 

(31)

GUANO 

CAVE 

(26) 

15 miles

SEPARATION HINDU 

CANYON CANYON 

(34) (35) 

20 miles ^ ^ 1 miles

D'

Southeast

BLUE MOUNTAIN 

CANYON 

(19) 

19 miles ^

Hermit Shale

Watahomigj Format! 

Recent 

erosion

-LA-r Redwall LimestoneiS1

Sandstone

JE---^-:::| Flat-bedded

S--:; :%:4 Cross-stratified

prf^TTT1] Siltstone

R^pq Mudstone 

1 Limestone

EXPLANATION 

y ,' > ,' t\ Dolostone 

£<?«?«? 1 Conglomerate

1 CD O C30|

___

xs 

Cone. 

L 

Wb

Erosion surface

Cross-strata 

Concealed 

Land plants 

Worm boring (trail)

Sc Shrinkage cracks

rm Ripple marks

R Rivularites sp.

J Jasper

f Fossils, invertebrate

— Atokan-Morrowan boundary

m

Sandstone, dominant grain size (Wentworth scale) 

VF Very fine grained 

F Fine-grained 

M Medium-grained

FIGURE A5.—Stratigraphic profiles of Supai Group and Pakoon Limestone (McNair, 1951; equivalent to lower part of Esplanade Sandstone in 

western Grand Canyon, Arizona) along line D-D' (fig. A1). Horizontal distance in miles is not to scale.

Gilmore, C. W., 1927, Fossil footprints from the Grand Canyon; second 

contribution: Smithsonian Miscellaneous Collection, v. 80, no. 3, 

78 p.

____1928, Fossil footprints from the Grand Canyon; third contribution: Smithsonian Miscellaneous Collection, v. 80, no. 8,16 p.

Heath, C.P.M., 1965, Microfacies of the Lower Bird Spring Group (Pennsylvanian-Permian), Arrow Canyon Range, Clark County, Nevada: 

Illinois University, Ph. D. thesis, 163 p.

Heath, C.P.M., Lumsden, D. N., and Carozzi, A. V., 1967, Petrography 

of a carbonate, transgressive-regressive sequence The Bird Spring 

Group (Pennsylvanian), Arrow Canyon Range, Clark County, Nevada: Journal of Sedimentary Petrology, v. 37, p. 377-400.

Huddle, J. W., and Dobrovolny, E., 1945, Late Paleozoic stratigraphy 

and oil and gas possibilities of central and northeastern Arizona: 

U.S. Geological Survey Oil and Gas Investigations Preliminary 

Chart 10.
INTRODUCTION

FEET 

1100

1000

900

800

700

600

500

400

300

200

100

50

0

£

West

ICEBERG 

CANYON

,„ , 35.5 miles

£'

North

HIDDEN PIGEON WASH SNAP

CANYON GRAND GULCH MINE CANYON

(30a,b) __ ,, c.., (28,29) m .. (27) 17.5 miles 4 miles

15

£" 

East

TWIN SPRINGS 

CANYON

oo ., (25) 22 miles

Sandstone 

Flat-bedded

Cross-stratified 

Siltstone 

Mudstone

EXPLANATION

Limestone 

Dolostone 

Conglomerate

Erosion surface 

xs Cross-strata

Cone. Concealed

L Land plants

Wb Worm boring (trail)

Sc Shrinkage cracks

R Rivularites sp.

f Fossils, invertebrate

Sandstone, dominant grain size (Wentworth scale)

VF Very fine grained

F Fine-grained

M Medium-grained

FIGURE A6.—Stratigraphic profiles of upper part of Supai Group and Pakoon Limestone (McNair, 1951; equivalent to lower part of Esplanade 

Sandstone in western Grand Canyon, Arizona) along line E-E'-E" (fig. A1). Horizontal distance in miles is not to scale.

Hughes, P. W., 1949, History of the Supai Formation in Black Mesa, 

Yavapai County, Arizona: Plateau, v. 22, no. 2, p. 32-36.

____1952, Stratigraphy of Supai formation, Chino Valley area, Yavapai County, Arizona: American Association of Petroleum Geologists 

Bulletin, v. 36, no. 4, p. 635-657.

Jackson, R. L., 1951, The stratigraphy of the Supai Formation along the 

Mogollon Rim, central Arizona: Arizona University, M.S. thesis, 

82 p.

Langenheim, V.A.M., and Langenheim, R. L., 1965, The Bird Spring 

Group, Chesterian through Wolfcampian at Arrow Canyon, Arrow 

Canyon Range, Clark County, Nevada: Illinois State Academy of 

Science Transactions, v. 58, p. 225-240.

Lokke, D. H., 1962, Paleontological reconnaissance of subsurface Pennsylvanian in southern Apache and Navajo Counties, Arizona: 

New Mexico Geological Society 13th Field Conference Guidebook, 

p. 84-86.

Lumsden, D. N., 1965, Microfacies of the Middle Bird Spring Group 

(Pennsylvanian-Permian), Arrow Canyon Range, Clark County, 

Nevada: Illinois University, Ph. D. thesis, 110 p.

Lumsden, D. N., Ledbetter, M. T., and Smith, G. T., 1973, Lithostratigraphic analysis of the Bird Spring-Callville Group and Pakoon Formation (Pennsylvanian-Lower Permian), southern Clark County, 

Nevada: Journal of Sedimentary Petrology, v. 43, no. 3, p. 655-671.
16 THE SUPAI GROUP OF GRAND CANYON

£

West

ICEBERG 

CANYON 

(31)

I*- -

£'

North

HIDDEN 

CANYON 

(30a,b) 

33.5 miles

PIGEON 

WASH 

(28) 

17.5 miles _

SNAP 

CANYON 

(27) 

4 miles u ^

Redwall Limestone

FIGURE A7.—Stratigraphic profiles of lower part of Supai Group and Pakoon Limestone (McNair, 1951;

in western Grand Canyon, Arizona) along line £-£'-£" (fig. A1). Horizontal

McKee, E. D., 1937, Researches on Paleozoic stratigraphy in western 

Grand Canyon: Carnegie Institution of Washington Year Book 36, 

p.332-345.

____1938, Researches on Paleozoic stratigraphy in Grand Canyon: 

Carnegie Institution of Washington Year Book 37 (1937-38), p. 358.

____1940a, Three types of cross-lamination in Paleozoic rocks of 

northern Arizona: American Journal of Science, v. 238, no. 11, 

p. 811-824.

____1940b, Studies on the history of Grand Canyon Paleozoic formations: Carnegie Institution of Washington Year Book 39 (1939-40).

_____1947, Paleozoic seaways in western Arizona: American Association of Petroleum Geologists Bulletin, v. 31, no. 2, p. 282-292.

_____1951, Sedimentary basins of Arizona and adjoining areas: Geological Society of America Bulletin, v. 62, no. 5, p. 481-505. 

.1975, The Supai Group Subdivision and nomenclature: U.S.

Geological Survey Bulletin 1395-J, p. Jl-Jll.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v.35, no. 3, p. 503-541.

Marcou, Jules, 1856, Resume and field notes, in U.S. Pacific Railroad 

Exploration: U.S. 33d Congress session, Senate Executive Document 

78 and House of Representatives Executive Document 91, v. 3, 

pt. 4, Geological Report, p. 165-171.

Merrill, W. M., and Winar, R. M., 1958, Molas and associated formations in San Juan basin-Needle Mountains area, southwestern Colorado: American Association of Petroleum Geologists Bulletin, v. 42, 

no. 9, p. 2107-2132.

Newberry, J. S., 1861, Geological report, in ]. C. Ives, Report upon the 

Colorado River of the West: U.S. 36th Congress, 1st Session, Senate 

Executive Document and House Executive Document 90, p. 3, Geological Report, p. 59, 62-64.

Noble, L. F., 1922, A section of the Paleozoic formations of the Grand 

Canyon at the Bass Trail: U.S. Geological Survey Professional Paper 

131-B, p. 23-73.

O'Sullivan, R. B., 1965, Geology of the Cedar Mesa-Boundary Butte 

area, San Juan County, Utah: U.S. Geological Survey Bulletin 1186, 

128 p.

Peirce, H. W., 1958, Permian sedimentary rocks of the Black Mesa Basin 

area, in Guidebook of the Black Mesa Basin, northeastern Arizona; 

New Mexico Geological Society, 9th Field Conference, Oct. 1958: 

p. 82-87.

Peirce, H. W., and Gerrard, T. A., 1966, Evaporite deposits of the Permian Holbrook basin, Arizona, in Symposium on salt, 2d v. 1, 

Geology, geochemistry, mining: Cleveland, Ohio, Northern Ohio 

Geological Society, p. 1-10.

Peterson, J. A., 1959, Petroleum geology of the Four Corners area: World 

Petroleum Congress, 5th, New York, 1959, Proceedings, sec. 1, 

p. 499-523.

Peterson, J. A., and Ohlen, H. R., 1963, Pennsylvanian shelf carbonates, 

Paradox basin, in Shelf carbonates of the Paradox basin, a symposium Four Corners Geological Society, 4th Field Conference, 1963: 

Durango, Colo., Petroleum Information Corp., p. 65-79.

Powell, J. W., 1875, Exploration of the Colorado River of the West and 

its tributaries explored in 1869-1872: Smithsonian Institution, 291 p.
INTRODUCTION 17

E"

East

TWIN SPRINGS 

CANYON

(25) 

22 miles EXPLANATION

Sandstone 

1 Flat-bedded

!&££] Cross-stratified

tli—lS] Siltstone

P>E^ Mudstone

III Limestone

Y,' I,' '\ Dolostone

pc^c^c? Conglomerate

"~^~~^ Erosion surface

XS Cross-strata

Cone. Concealed

Wb Worm boring (trail)

Sc Shrinkage cracks

J Jasper

O Stromatolites

f Fossils, invertebrate

Sandstone, dominant grain size (Wentworth scale)

VF Very fine grained

F Fine-grained

M Medium-grained

Redwall 

Limestone

equivalent to lower part of Esplanade Sandstone 

distance in miles is not to scale.

Ross, C. A., 1973, Pennsylvanian and Early Permian depositional history, southeastern Arizona: American Association of Petroleum

Geologists Bulletin, v. 57, no. 5, p. 887-912. 

Sears, J. D., 1956, Geology of Comb Ridge and vicinity north of San

Juan River, San Juan County, Utah: U.S. Geological Survey Bulletin

1021-E, p. 167-207. 

Sorauf, J. E., 1962, Structural geology and stratigraphy of the Whitmore

area, Mohave County, Arizona: Kansas University, Ph. D. thesis,

361 p. 

Steele, G., 1959, Stratigraphic interpretation of the PennsylvanianPermian Systems of the eastern Great Basin: Washington University,

Ph.D. thesis, 294 p. 

Walcott, C. D., 1880, The Permian and other Paleozoic groups of the

Kanab Valley, Arizona: American Journal of Science, ser. 3, v. 20,

p. 221-225. 

Welsh, J. E., 1959, Biostratigraphy of the Pennsylvanian and Permian

Systems of southern Nevada: Utah University, Ph. D. thesis, 106 p.

Wengerd, S. A., and Matheny, M. L., 1958, Pennsylvanian System of 

Four Corners region: American Association of Petroleum Geologists 

Bulletin, v. 42, no. 9, p. 2048-2106.

Wentworth, C. K., 1922, A scale of grade and class terms for clastic sediments: Journal of Geology, v. 30, no. 5, p. 377-392.

White, David, 1927, Study of the fossil flora in the Grand Canyon, Arizona: Carnegie Institution of Washington Year Book 26 (1926-27), 

p. 366-369.

____1928, Study of the fossil floras in the Grand Canyon, Arizona: Carnegie Institution of Washington Year Book 27 (1927-28), p. 389-390.

____1929, Flora of the Hermit Shale, Grand Canyon, Arizona: Carnegie Institution of Washington Publication 405, 221 p.

Winters, S. S., 1951, Permian stratigraphy in eastern Arizona: Plateau,

v. 24, no. 1, p. 10-16. 

____1963, Supai formation (Permian) of eastern Arizona: Geological

Society of America Memoir 89, 99 p.
18 THE SUPAI GROUP OF GRAND CANYON

F

West

SNAP

CANYON

(27)

21 miles

ANDRUS PARASHANT WHITMORE 

CANYON CANYON WASH 

(24) (23) (22) 

5.5 miles 7 miles , 8 miles

TOROWEAP

VALLEY

(21)

FEET 

1100

1000 - 

900 - 

800 - 

700 

600

500

400

300

200

100

50

0

FIGURE A8.—Stratigraphic profiles of Supai Group and Pakoon Limestone (McNair, 1951; equivalent to lower part of Esplanade Sandstone in 

western Grand Canyon) along line F-F (fig. A1). Horizontal distance in miles is not to scale.
INTRODUCTION 19

TUCKUP 

CANYON

(18) 

12.5 miles 7 miles

S B KANAB 

CANYON CANYON

(17) (16) ^ 8 miles

THUNDER RIVER 

TRAIL

(12) 

13 miles 9.5 miles

F'

East

SHINUMO 

TRAIL 

(11)

., .jj

Sandstone 

Flat-bedded

Cross-stratified 

Siltstone 

Mudstone 

Limestone

EXPLANATION

Dolostone

Gypsum

Conglomerate

Erosion surface

xs Cross-strata

Cone. Concealed

L Land plants

Wb Worm boring (trail)

Sc Shrinkage cracks

rm Ripple marks

J Jasper

O Stromatolites

f Fossils, invertebrate

^ Atokan-Morrowan boundary 

Sandstone, dominant grain size (Wentworth scale;

VF Very fine grained

F Fine-grained

M Medium-grained

THE SUPAI GROUP OF GRAND CANYON

INTRODUCTORY SUMMARY

Chapter B 

By EDWIN D. McKEE

Contents

Supai history ..... ......

Pre-Supai deposits . .....

Watahomigi Formation ....

Manakacha Formation . . 

Wescogame Formation ....

Esplanade Sandstone .....

Termination of Supai Group 

Reference cited ..........

Page

23

23

23

23

24

25

27

27

21

INTRODUCTORY SUMMARY 23

SUPAI HISTORY

The Pennsylvanian and Early Permian history of the 

Grand Canyon region consists principally of a series of 

four transgressions. Deposits of each transgression were 

more widespread than those of the preceding one, and included both marine and continental sediments. A period of 

nondeposition recorded by a widespread erosion surface 

marks the termination of each depositional cycle. The 

principal times of deposition are represented by the four 

formations of the Supai Group. Hiatuses between these 

formations, recorded by erosion surfaces, are of very different magnitudes, but all are of appreciable size.

PRE-SUPAI DEPOSITS

Events preceding deposition of the Supai and leading 

up to its evolutionary history consist of a regional uplift, 

probably epeirogenic, following retreat of the Redwall sea 

at the end of Early Mississippian time. The uplift 

amounted to at least several hundred feet in the Grand 

Canyon area as. one or more narrow valleys, approximately 400 ft deep, were carved by westward-flowing 

streams near its western margin. Following this tectonism, 

a change in relative sea level apparently caused the filling 

of these valleys with sediments, first with fluviatile 

deposits preserving land plants, and later with beds of carbonate sediments containing marine fossils of Late Mississippian (Chesterian) age.

WATAHOMIGI FORMATION

The history of the Watahomigi, the lowest formation of 

the Supai Group*, began with an eastward transgression of 

the sea from the Cordilleran geosyncline into a restricted 

embayment in the Grand Canyon area. The sea advanced 

over a relatively flat but uneven surface, formed partly by 

karst topography at the top of the Redwall Limestone and 

partly by Chesterian strata that filled stream-cut valleys 

carved in the Redwall. A thin sheet of gravel, composed 

mostly of durable pebbles such as chert and flint, and locally containing brachiopods or other marine fossils, was 

spread over much of the area and was followed by layers 

of mud, silt, and eventually by carbonate deposits.

The Watahomigi Formation averages about 300 ft thick 

in western Grand Canyon, about 200 ft in the central area, 

and 100 ft in the eastern part. The embayment was connected with the sea only along the west and northwest 

margins and, as determined by isopachs, probably was 

bordered by land in all other directions. Lithologic analyses indicate that the deposits in this embayment consisted

mostly of carbonate sediment (60-90 percent) with some 

silt and argillaceous mud (10-40 percent) in the west, and 

dominantly of mud (50-85 percent) with relatively little 

carbonate sediment (15-35 percent) in the east. Sand was 

absent in the west and formed less than 15 percent in central and eastern localities.

The Watahomigi consists of three units, all of which 

are progressively thinner eastward. The lower two, as indicated by brachiopods, are of Morrowan age, whereas the 

upper is shown by fusulinids to be of Atokan age. Bioclastic debris, consisting of pelmatozoan, foraminifer, 

bryozoan, and bivalve fragments, occurs in all units and is 

common in many places in western Grand Canyon. However, this fossil debris is absent in all but a few localities in 

eastern Grand Canyon. Such distribution probably results 

from lack of marine connections at this time with seas to 

the northeast and to the southeast.

Clay minerals, like the fossils in the Watahomigi, show a 

relationship to environment; marine clays such as illite, 

chlorite, and corrensite are commonly associated with carbonate rocks of the western Grand Canyon, but kaolinite, 

which is considered nonmarine, probably deltaic, occurs in 

eastern Grand Canyon. The presence of some illite and 

corrensite, also in the eastern area, probably indicates local 

marine incursions that extended eastward beyond the main 

seaway at that time. A general lack of sand and accumulations of carbonate mud probably indicate a low-energy 

environment in most of the Grand Canyon embayment.

The amount of sandstone in the Watahomigi is very 

small compared with that in the other three formations of 

the Supai Group. It consists almost entirely of very fine 

grained sand, with only small amounts of coarser grains 

such as are common in the overlying formations. The proportion of sand to silt is about 1:3, whereas the overlying 

formations show between two and five times as much sand 

as silt. The percentage of samples that are skewed (25 percent) is low compared with that of the other formations. 

Large-scale cross-bedding is absent; small-scale, in the 

form of ripple laminae and climbing ripples, is only locally 

common. In brief, evidence furnished by the sandstone 

confirms evidence from other sources that a low-energy 

environment prevailed throughout the Grand Canyon 

embayment when the Watahomigi was being deposited.

MANAKACHA FORMATION

The Manakacha Formation, which is largely or entirely 

of Atokan age, is represented in the Grand Canyon region 

by several hundred feet of sediment, mostly marine, that 

filled an embayment much like that of the preceding Morrowan time. The principal difference in the paleogeography 

as recorded in these two formations is that during Atokan 

time the sea that transgressed from the southwest extended
24 THE SUPAI GROUP OF GRAND CANYON

farther northeastward and connected with waters of the 

San Juan Basin in the Four Corners area of Arizona, New 

Mexico, Colorado, and Utah. The axis of maximum thickness as shown by an isopach map (fig. DlO) confirms this 

trend, and illustrates why thickness of the Manakacha is 

essentially the same in western, central, and eastern Grand 

Canyon. A landmass, however, apparently still lay to the 

south and southeast.

Lithologically, the Manakacha differs greatly from the 

earlier Watahomigi. The Manakacha contains considerably 

more sandstone (10-30 percent in western Grand Canyon 

and 20-50 percent in eastern Grand Canyon) as compared 

to no sandstone in the west and only a few percent in the 

east for the Watahomigi. On the other hand, both mudstone and carbonate rock are mostly considerably less in 

the Manakacha than in the Watahomigi for corresponding 

areas. In the Manakacha, mudstone ranges from as much 

as 10 percent in the west to 30-60 percent in the east; carbonate rock forms from 35-90 percent in the west, but only 

5-20 percent in the east.

Faunal distribution in the Manakacha seems to be largely 

facies-controlled; however, it reflects to some degree the 

continuous passageway of the sea to the northeast. Three 

genera of fusulinids recorded from Atokan rocks of southern Nevada likewise occur in western Grand Canyon 

strata; two genera have also been found in eastern Grand 

Canyon. Although complete fossils of various other 

groups seem to be restricted to limestone facies of western Grand Canyon, numerous forms occur as bioclastic 

debris in strata of central and eastern, as well as western, 

Grand Canyon. Clasts of pelmatozoans, calcispherids, 

algae (Girvanella), and bivalves are recorded from various 

parts of central Grand Canyon, and all of these but the 

bivalves have been noted in eastern sections.

A large percentage of clays in the Manakacha are 

types considered to be marine. Illite is abundant in the 

northwestern part of the embayment where it probably is 

marine, as indicated at Andrus Canyon where 80 percent is 

associated with limestone. Some illite also occurs at scattered localities in eastern Grand Canyon. In that area, 

however, it is associated with continental sediments and is 

believed to have been derived from degraded detrital 

micas. For that reason, it probably does not constitute an 

indicator of depositional environment.

Corrensite, a clay of probably marine origin, has been 

recorded only from the western part of Grand Canyon. It 

is seldom, if ever, associated with sandstone in the Manakacha Formation and is believed to represent a low-energy, 

marine environment of restricted waters, especially in the 

vicinity of Toroweap Point and of Separation Canyon.

Eastward in Grand Canyon, from Havasu and Fishtail 

Canyons, marine deposits merge into continental, indicated by the presence of kaolinite as the common clay. In 

most places, the kaolinite is associated with silt and mud.

Principal areas in which these fine-grained detrital sediments are concentrated in the Manakacha are seen on the 

cross-section diagrams (fig. P8). They occur in (1) the 

southwestern part of the region where a probable source of 

terrigeneous material was farther south or southeast, and 

(2) the eastern and northeastern Grand Canyon region 

where waters from the western embayment merge with 

those from the San Juan Basin to the east, forming an area 

of shoals.

Although sandstone of the Manakacha is mostly very 

fine grained throughout the region, it contains fine sand as 

the dominant size grade in the east, three localities, and in 

the west, one locality. Likewise, in both east and west but 

not in the middle, maximum grain sizes consisting of very 

coarse sand and coarse sand occur at numerous localities, 

suggesting, by their distribution, dual directions of source. 

Good sorting is shown in 72 percent of samples; 28 percent 

show medium sorting. A high degree of roundness is a 

common attribute of nearly all the sand, in contrast to 

angular shapes of the silt grains. As with other formations 

of the Supai, probably roundness is a function of grain size 

and is not directly related to distance of transport or to 

genesis.

Cross-stratification in sandstone of the Manakacha is 

dominantly medium scale, but includes a considerable 

amount of large scale. It is mostly tabular-planar, although 

wedge-planar is common; trough type has not been recorded. Angles of foreset dips are about equally distributed above and below 20° (high angle and low angle, 

respectively) and can be as high as 27°-28°. Dip-direction 

vectors are southerly and have a spread of 71°, or less than 

one quadrant. All of these features of cross-strata are 

similar to those of the overlying Wescogame, except that in 

the Manakacha the dip directions are more restricted 

(smaller spread) and are more southerly.

WESCOGAME FORMATION

Deposition of the Wescogame Formation of Virgilian 

age in the Grand Canyon region followed a large hiatus in 

the stratigraphic record, representing most or all of Des 

Moinesian time and all of Missourian time. The unconformable surface on which deposition began is marked by 

numerous channels and depressions that are as much as 

80 ft in depth. Initial deposits in most places are rounded 

gravels of siltstone and limestone, probably derived from 

the underlying Manakacha Formation. These gravels partially fill channels and spread extensively to form a thin 

blanket conglomerate. In western Grand Canyon, most of 

the formation above the gravel is composed of carbonate 

rock (50-75 percent) and sandstone (10-50 percent), but in 

the east much sandstone (70-90 percent) and some mudstone (20-35 percent) overlie the conglomerate.
INTRODUCTORY SUMMARY 25

An isopach map (fig. Dll) of the Wescogame Formation 

resembles that of the underlying Manakacha except that 

the seaway is more extensive and a landmass to the south is 

missing. As in Atokan time, a connection between the 

Grand Canyon embayment and the San Juan Basin to the 

northeast is apparent. Thickness of deposits in the embayment ranges from 150 ft in the west to about 100 ft in the 

central and eastern parts.

The marine fauna of the Wescogame is largely 

restricted to the1 carbonate rock facies along the western 

margin of the formation. It consists mostly of fusulinids, 

pelecypods, gastropods, and pelmatozoans. These fossils 

do not occur, however, in the high-energy deposits of 

cross-stratified sandstone in middle and eastern Grand 

Canyon except in the form of bioclasts. Brachiopods have 

not been found in the formation and fusulinids are not 

known from the eastern part of the area.

Marine clays of the Wescogame are largely confined to 

the extreme western part of the embayment. Compared to 

the underlying formations, the amount of authigenic illite 

in the Wescogame is small. Among the sand deposits from 

Andrus Canyon eastward, minor amounts of illite seem to 

have developed in what probably were lagoons isolated 

from the sea by migrating sands. Near Kaibab Trail, north, 

one such deposit contains some possible corrensite with 

illite.

Kaolinite, here as in the other formations, is the second 

most common clay mineral and occurs exclusively among 

sands and silts. Its relative abundance, therefore, suggests 

an increase in the eastern part of the region in the percentage of continental deposits over those of the preceding formations, and its interface with the illite deposits marks 

shorelines of vairious stages. Chlorite occurs at scattered 

localities, but seems to be mostly detrital and probably 

contributes no information concerning the paleogeography.

The abundant sandstone foresets of eastern Grand Canyon contain well-preserved footprints of four-footed vertebrate animals probably amphibians or reptiles in a 

number of scattered localities. These tracks indicate the 

proximity of land and give a possible explanation for the 

dearth of skeletal accumulations derived from marine animals. Except for local accumulations of worn and comminuted fragments of pelmatozoans, bivalves, and a few 

other invertebrate animals that may have been transported 

from afar, faunal evidence favors the interpretation of a 

continental environment in eastern Grand Canyon.

Sand of the Wescogame has most of the features characteristic of sand in the underlying Manakacha, even 

though separated from it by a large stratigraphic break. 

The sand likewise is dominantly very fine grained, and, in 

scattered localities both in the east and in the west, contains coarse-grained maxima. In the northwest, some samples include very coarse grains. Such a distribution pattern, together with the orientation of cross-strata direction

vectors pointing southward, seems to indicate that, as with 

the Manakacha, a sand source was to the north and northwest, and initial transportation routes were into the 

eastern and far western parts of the embayment, with 

lesser concentration in the middle area. The sorting of sand 

in most cases is good, but in a few areas it is only 

moderate. A large majority of grains are rounded, in contrast with the largely angular shapes of associated silt 

grains, suggesting that the rounding is a function of grain 

size.

Cosets of cross-strata in the Wescogame include the 

largest in the Supai Group as much as 40 ft thick and 

the sets contain many large-scale tabular-planar and 

wedge-planar foresets. Medium-scale cross-strata are also 

common, but small-scale types are rare. The ratio of sand 

to silt is about 4:1, much greater than in the two underlying formations, and the percentage of skewed samples is 

moderately high. All of these features seem to indicate a 

depositional environment involving high energy and a 

progressively greater increase in current activity with each 

extension of the embayment following the beginning of 

Pennsylvanian time.

ESPLANADE SANDSTONE

Strata of the Esplanade Sandstone and its western correlative, the Pakoon Limestone (McNair, 1951), have the 

greatest thickness and are the most widespread of any formation in the Supai Group. These deposits extend through 

the entire Grand Canyon area, thickening toward the 

northeast, north, northwest, and west; probably also they 

once were continuous with thick deposits of similar age in 

southeastern Arizona. Only two small areas within the 

region one to the east (Defiance positive element) and the 

other to the south show positive trends. Thus, nearly the 

entire shelf was a surface of deposition. Thickest deposits, 

indicating belts of maximum sinking, extended outward in 

the form of troughs toward the San Juan Basin, the Cordilleran geosyncline, and the Sonoran geosyncline.

Deposition in Early Permian (Wolfcampian) time began 

on a relatively flat surface of the Wescogame Formation, 

dissected by numerous small channels from a few feet to a 

maximum of about 35 ft in depth. These channels were incised by streams when the region was elevated slightly 

above sea level during the hiatus between Pennsylvanian 

and Permian time. Initial deposits on this surface probably 

represent a continental environment and consist mostly of 

conglomerate that fills or partly fills the channels and 

forms a sheet covering most of the interfluves. The conglomerate is composed of well-rounded gravels of siltstone 

and limestone apparently derived from the underlying 

Wescogame Formation and deposited by streams. Only in 

the extreme west are these basal deposits associated with 

marine fossils, indicating burial under the sea.
26 THE SUPAI GROUP OF GRAND CANYON

The Esplanade Sandstone is readily divisible into two, 

and locally three, units based on lithology and topographic 

expression. The basal slope-forming unit consists of much 

mudstone or siltstone (17-81 percent) and a similar 

amount of fine to very fine sandstone (12-75 percent). 

In far western Grand Canyon the basal slope unit of the 

Pakoon Limestone, in which carbonate rocks occur in 

small amount (1-7 percent), occupies a similar position at 

the bottom. Uncommon fossils indicate that these units are 

at least partially continental.

The main cliff-forming unit of the Esplanade is a thick 

unit of cross-stratified sandstone (74-100 percent) that 

clearly indicates a high-energy environment within the 

central and eastern Grand Canyon areas at the time of 

deposition. In contrast, in the western part of the region 

this unit is represented by thick-bedded carbonate rocks 

(90-98 percent), mostly dolostone (Pakoon Limestone), 

that intertongue with sandstone of the Esplanade within a 

short distance to the east.

The uppermost cliff-slope unit of the Esplanade, represented only in the northern and western parts of the 

region, consists largely of fine- or very fine grained detrital 

sediment. In some areas to the northwest, it includes beds 

of gypsum and gypsiferous sandstone. In areas where this 

unit is well developed, an appreciable additional amount 

of sediment adds to the thickness of the formation, and the 

implication is that increased basin sinking in these areas 

was responsible. The sea apparently was withdrawing at 

this time, leaving its record of residual-type sediments and 

concentrating the water.

The Pakoon along the western margin contains an abundance of marine fossils including corals, pelmatozoans, 

and bivalves; farther east the sandstones of the Esplanade 

apparently represent an environment that was inhospitable 

to most forms of life. Except for a few scattered fusulinids, 

the faunal record consists of bioclasts only. Fossil 

fragments that have been recorded include bivalves, 

pelmatozoans, bryozoans, and foraminifers. These bioclasts occur throughout the region in limited numbers but 

are more common in the western than in the central or 

eastern parts of Grand Canyon.

Distribution of clay minerals in the Esplanade Sandstone 

differs in several important respects from that in the other 

formations of the Supai Group. Especially noteworthy is 

the relative scarcity of illite a mineral largely confined to 

the carbonate rocks in this formation. Illite, believed to be 

authigenic, occurs in dolostone at Hidden and Iceberg 

Canyons on the western margin of the area; it is in 

calcareous or dolomitic lenses where associated with sandstone. At Andrus Canyon, illite is among evaporitic 

deposits in the gypsum facies. No illite has been recorded 

east of Toroweap Point in this area.

Corrensite, which, like illite, commonly develops in a 

marine environment, is uncommon in the Esplanade, although it also is present in the gypsum facies at Andrus 

Canyon and seems to reflect quiet-water conditions. Chlorite, associated with sand, silt, and mud, is confined to 

the upper cliff-slope unit and is believed to be of detrital 

origin. The most abundant clay in the formation, except 

the random mixed-layer type, is kaolinite. This clay is 

primarily in the sandstones. Because it is considered of 

continental origin and is especially abundant east of Andrus Canyon and Prospect Valley, its western boundary 

probably marks a continental-marine interface in the 

formation. Kaolinite probably represents an oxidizing 

environment where iron oxides are present and where 

feldspar-bearing rocks furnish a source.

Analyses of sand composing the Esplanade Sandstone 

show that, like sand in the underlying formations of the 

Supai, it is composed largely of very fine grains and in 

most places is well sorted (75 percent, good sorting; 25 percent, medium sorting). Unlike sands of the Wescogame 

and Manakacha Formations, however, those of the Esplanade are coarsest in the central part of the Grand Canyon 

region where very coarse grains are recorded from five 

localities. In this part of the region, mean size grades were 

determined to be medium sand at a few localities and fine 

sand at many others. As in the earlier formations, grains of 

all sand sizes show good rounding, but the silt-size grains 

are angular. The proportion of sand to silt (5:1) is greater 

than in any of the earlier Supai formations.

Cross-strata of the Esplanade Sandstone constitute what 

is probably its outstanding characteristic. Like cross-strata 

of the underlying Wescogame, about half the sets are of the 

tabular-planar type and half are of the wedge-planar type; 

trough cross-strata are rare. Also similar are the angles of 

dip of foresets, because in both formations the number of 

high-angle examples (>20°) and the number of low-angle 

examples (< 20°) are about equal. Maximum dip degrees of 

foresets are about 27° or 28° in bpth units.

Despite certain similarities between cross-stratification 

in the Esplanade and that in the Wescogame, some major 

differences are apparent. Analyses of directional vectors 

of foreset dip surfaces indicate that the mean regional 

direction was considerably more toward the east during 

Esplanade deposition (southeast) than for the older Supai 

formations (south). Further, the average spread of dip 

directions is more restricted in Esplanade cross-beds (57°) 

than in the underlying formations.

The thickness of cosets that consist of successions of 

planar cross-strata tends to be greater in the Wescogame 

(maximum 40 ft) than in the Esplanade (maximum 27 ft). 

This probably is because of larger scale foresets included; 

however, the number of sets represented in a coset commonly is greater in the Esplanade where a repetition of 

medium-scale foresets seems to be normal in contrast to 

fewer but larger sets in the Wescogame.
INTRODUCTORY SUMMARY 27

TERMINATION OF 

SUPAI GROUP

Deposition of the Supai Group in the Grand Canyon 

region ended with the development of a widespread surface 

of erosion near sea level. Small stream channels (as much 

as 55 ft deep) dissected this surface in many places, but 

otherwise it app;arently was extremely flat and even. Basal 

units of the Hermit Shale that overlie the Supai and fill the 

channels across the region consist of shaly silt and other 

fine detrital sediments; they contain land plants of xerophytic types and sedimentary structures of many varieties. 

Conglomerates are absent, and therefore a relatively short 

hiatus is probably represented suggesting that consolidation of the underlying Supai sediments had not been attained before deposition of the basal units of the Hermit 

Shale.

REFERENCE CITED

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

THE SUPAI GROUP OF GRAND CANYON

STRATIGRAPHY AND LITHOLOGY

Chapter C 

By EDWIN D. McKEE

Contents

Stratigraphy ..........................................

General character of the Supai Croup ..................

Stratigraphic nomenclature in westernmost Grand Canyon

Formations comprising the Supai Croup ................

Type sections ............. .......................

The Watahomigi Formation ..........................

The Manakacha Formation ......... ................

The Wescogame Formation ..........................

The Esplanade Sandstone ..........................

Lithology ............................................

Lithology of the Watahomigi Formation ................

Lithology of the Manakacha Formation .................

Lithology of the Wescogame Formation ................

Lithology of the Esplanade Sandstone ..................

References cited ......................................

Page

31

31

31

35

35

39

40

40

41

46

46

46

47

48

50

29
30 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURE C1. Generalized Supai profile showing formations, their subdivisions, and key conglomerate beds ........................................................ 32

C2. Photographs showing general views of the Supai Group .......... .............. 33

C3. Photographs showing section of Supai Group exposed in various areas of western

Grand Canyon ........................................................ 34

C4. Map of Havasu Canyon, Arizona, showing localities of type sections of the Watahomigi, Manakacha, and Wescogame Formations and the Esplanade Sandstone ..... 38

C5. Photographs of the Watahomigi and Manakacha Formations ..................... 39

C6. Maps showing thickness distribution of Supai formations ........................ 41

C7. Photographs of strata of the Wescogame Formation ............................ 42

C8. Columnar sections showing principal rock types of Esplanade Sandstone ........... 43

C9. Photographs of the Esplanade Sandstone ..................................... 45

C10-C13. Bar graphs showing proportion of rock types in the:

CIO. Watahomigi Formation ........................................... 47

C11. Manakacha Formation ............................................ 48

C12. Wescogame Formation ........................................... 49

C13. Esplanade Sandstone ............................................. 50

Tables

Page

TABLE C1. Summary of classifications of Supai strata ..................................... 35

C2. Thickness of subdivisons of the Supai Group .................................. 36

C3. Percentages of sandstone, mudstone, and carbonate rocks in Esplanade Sandstone ..... 44
STRATIGRAPHY AND LITHOLOGY 31

STRATIGRAPHY

General character of 

the Supai Group

The unifying features of the Supai Formation as originally defined by Darton (1910, p. 25) were its characteristic 

red-bed components, consisting largely of sandstone and 

sandy shale. On this basis, it was considered distinctive 

and was clearly separable from the white Coconino Sandstone above and from the dominantly massive gray limestone of the Redwall below. At that time the Redwall, as 

defined, included in its upper part units of red silty 

mudstone, alternating with beds of limestone. The Supai 

was redefined by Noble (1922, p. 59) some years later after 

he examined in detail and measured stratigraphic sections 

along the Hermit and Bass Trails in Grand Canyon. Instead of using lithology and color to determine its boundaries, he delineated the formation on the basis of breaks in 

the stratigraphic sequence. Thus, the upper limit of the 

Supai was placed at an erosional surface a few hundred 

feet below the former top, and its base was lowered to an 

erosional surface separating the massive limestone of the 

Redwall cliff from the alternating red mudstones and thinbedded limestones above.

Slope-forming beds of red shaly siltstone that overlie the 

uppermost erosional surface recognized by Noble in the 

Supai were assigned by him (Noble, 1922, p. 59) to a new 

formation, which he named Hermit Shale.

The lower boundary of the Supai was established by 

Noble (1922, p. 59) to conform with the concept that a 

stratigraphic break marked a meaningful and logical 

formation boundary. "Alternating sandstones and compact limestones, 200-500 feet" thick, formerly included in 

the underlying Redwall, were transferred to the Supai as its 

basal division. This change in assignment was justified, 

partly on the grounds that the red beds concerned resembled more closely the Supai strata than the massive limestone beds of the Redwall, but also because they were considered of Pennsylvanian age, whereas the Redwall was 

Mississippian, and a hiatus occurred between.

The stratigraphic approach in the present study has 

followed to a considerable extent the methods and procedure developed by Noble, but a principal difference is 

that this investigation has been extended across a much 

greater area. By establishing 32 control points, with a 

detailed measured section at each, the trends and changes 

in lithology and fauna have been established across an area 

roughly 150 by 60 mi (fig. Al). Reliable key conglomerate 

beds have permitted the tracing of rock units for great 

distances and the recognition of time-equivalent lithologic 

and faunal facies throughout a wide area.

The key beds that have been recognized and used as 

stratigraphic markers in this study are thin conglomerate

units that are distinctive lithologically (fig. Cl; table Hi). 

As described in an earlier publication (McKee, 1975, p. J2), 

they occur at four principal horizons and have widespread 

distribution in the Grand Canyon region. The uppermost 

conglomerate was recognized in 25 of 31 sections examined, the next lower conglomerate in 19 of 27 sections, and 

the third in 14 of 25 sections. The fourth conglomerate 

bed, at or near the base of the Supai, occurs at 22 localities.

The key conglomerate beds mark hiatuses, probably of 

considerable magnitude, within the sequence of red-bed 

deposits known as the Supai, therefore they constitute a 

major reason for subdividing the Supai formation, as 

defined by Noble (1922), into four formations. In 1975, as 

a result of the present investigation, the original formation 

was raised in rank to Supai Group and, as a result, removed from the Aubrey Group.

It is recommended that the Aubrey Group be abandoned 

as a result of the adoption of the name Supai Group for the 

lowermost part of the Aubrey Group in the Grand Canyon 

area, which includes Aubrey Cliffs, type locality for the 

Aubrey Group (see chapter A, this volume, pages 3-4, for 

a discussion of the history of the Aubrey Group).

Four formations are recognized within the Supai Group 

(oldest to youngest): Watahomigi, Manakacha, and 

Wescogame Formations and Esplanade Sandstone (McKee, 

1975, p. J2). These formations (figs. C2, C3) are mappable 

units because the strata included in each form topographically distinct features as a result of characteristic lithology. 

Thus, informal field terms for various rock units, based on 

topographic expression, as suggested to me in 1930 by F. E. 

Matthes of the U.S. Geological Survey, and followed 

throughout the present investigation can readily be converted into both rock units (formations of this paper) and 

time-equivalents (table Cl). The type section in Havasu 

Canyon, near Supai village, illustrates well (fig. MS2) the 

succession of red sandstone, limestone, and mudstone 

strata of the Supai Group.

Stratigraphic nomenclature in 

westernmost Grand Canyon

Equivalents of the Supai Group in extreme southeastern Nevada are the Callville and Pakoon Limestones, and 

the Queantoweap Sandstone. The Callville Limestone was 

described by Longwell (1921, p. 46-47) from southeastern 

Nevada (Muddy Mountains) as a limestone with interbedded shale in the upper part. As originally defined, it 

included rocks of Late Mississippian, Pennsylvanian, and 

Early Permian age and the type locality was designated as 

Callville Mountain, Clark County, Nev. Later, the formation was restricted by McNair (1951) to Pennsylvanian 

limestones below Permian dolostones (Pakoon) near the 

Arizona-Nevada boundary in the Lake Mead region. In 

westernmost Grand Canyon (Grand Wash Cliffs, Iceberg
32 THE SUPAI GROUP OF GRAND CANYON

Hermit Shale

Main cliff unit

Basal slope unit

-Basal conglomerate

_m^Turr_x Slope unit

Cliff unit

Basal conglomerate

jzrr^rr-LLrr\ Slope unit

EXPLANATION 

Sandstone 

Siltstone 

Conglomerate 

Limestone 

Jasper bands 

Mudstone 

Erosion surface

Cliff unit

—Zr—V Upper slope unit

Atokan 

conglomerate

Middle cliff 

unit

Lower slope

' unit Basal 

conglomerate

ESPLANADE 

SANDSTONE 

(250-850 ft)

WESCOGAME 

FORMATION 

(100-250 ft)

MANAKACHA 

FORMATION 

(200-300 ft)

WATAHOMIGI 

FORMATION 

(100-350 ft)

Redwall Limestone

FIGURE C1.—Generalized Supai profile showing formations, their subdivisions, and key conglomerate beds at bases of 

Esplanade Sandstone, Wescogame Formation, upper slope unit of Watahomigi Formation, and baseof Watahomigi.
STRATIGRAPHY AND LITHOLOGY 33

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Canyon), strata formerly referred to the Callville Limestone are included in the lower part of the Supai Group. 

The name Callville is now not used in the Grand Canyon 

area and is restricted to the carbonate-rock facies equivalents of the Watahomigi, Manakacha, and Wescogame 

Formations to the west. The Callville may also include 

some Chester-age limestones equivalent to those filling 

pre-Supai valleys in Grand Canyon.

FIGURE C2.—General views of the Supai Group in various parts of the 

Grand Canyon region, Ariz. A, Marble Canyon at Vasey's Paradise, 

view south; 6, view south toward Hualapai Plateau, looking up National Canyon; C, view west toward Shivwits Canyon, across Twin 

Springs Canyon; and D, west of Bunker Trail, eastern Grand Canyon. 

R, Redwall Limestone. Supai Group: Wa, Watahomigi Formation; 

M, Manakacha Formation; We, Wescogame Formation; E, Esplanade 

Sandstone. H, Hermit Shale. The Supai Group ranges from 800 to 

1,050 ft thick in these photographs.

The Pakoon Limestone was defined by McNair (1951, 

p. 524) as "a wedge of dolomitic limestones that lie between the upper member of the Callville limestone and the 

'Supai' redbeds." The type section is at Pakoon Ridge, 

Mohave County, Ariz., approximately T. 35 N., R. 16 W., 

where the formation is 688 ft thick, according to McNair. 

On the "north Grand Wash Cliffs" (probably near Pigeon 

Wash or Snap Canyon), McNair (1951, p. 525) measured a 

section, almost entirely of dolomitic limestone that was 

305.5 ft thick. It contained a fusulinid zone of Permian 

(Wolfcampian) age. In westernmost Grand Canyon the 

Pakoon is now thought, in the opinion of the author, to be 

equivalent to the lower part of the Esplanade Sandstone 

because it contains limestone tongues (Pakoon-equiva-
34 THE SUPAI GROUP OF GRAND CANYON

FIGURE C3.—Section of Supai Group as exposed in various areas of western Grand Canyon, Ariz. A, North side of Pigeon Wash, in Grand Wash 

Cliffs; 6, view north along Grand Wash from near Hidden Canyon; and C, west side of promontory, east of Guano Cave locality. R, Redwall 

Limestone. Supai Group: Wa, Watahomigi Formation; M, Manakacha Formation; We, Wescogame Formation. P, Pakoon Limestone (McNair, 

1951). The Manakacha is 210-260 ft thick in these photographs.
STRATIGRAPHY AND LITHOLOGY 35

TABLE C1.— Summary of past and present classifications of Supai strata

Subdivisions 

of Noble 

(1922, p. 61)

A

B

C

Informal field 

terms for 

rock units

Esplanade cliff

Upper slope

Middle cliff

Middle slope

Lower cliff

Lower slope

New formal 

terminology of 

Supai Group

Esplanade

Sandstone

Wescogame

Formation

Manakacha 

Formation

Watahomigi 

Formation

Age

Wolfcampian

Virgilian

Des 

Moinesian(?)

Atokan

Morrowan

lents?) farther to the east in west-central Grand Canyon. 

The "Queantoweap sandstone" is the name applied by 

McNair (1951, p. 525) to the "cliff-forming, cross-bedded 

sandstones which rest on the Pakoon and upper Callville 

limestones." His type section was "on the east side of 

Queantoweap Valley [Whitmore Wash] between the upper 

and lower lava flows," where it "forms a set of conspicuous ledges and cliffs below the easily eroded Hermit 

redbeds." This formation seems to be the same as the 

Esplanade Sandstone of the Supai Group, so the name 

Queantoweap is not recognized in this publication. Furthermore, the Pakoon does not occur below this (Esplanade) sandstone in Whitmore Wash, and probably is 

represented by the main cliff unit of the Esplanade Sandstone as shown by intertonguing elsewhere. If this correlation is correct, the Queantoweap of McNair at its type 

locality is a time-equivalent of the Pakoon farther west.

Formations comprising the 

Supai Group

The four formations of the Supai Group the Watahomigi, Manakacha, and Wescogame Formations and the 

Esplanade Sandstone not only are mappable units 

because of distinctive topographic expression (McKee, 

1975), but also are readily divisible into informal units for 

the same reason. The formations and most of the units are 

remarkably widespread (table C2), forming persistent 

slopes or cliffs for great distances. Indeed, most of them 

retain somewhat the same lithographic and topographic

character, changing primarily in thickness, from eastern to 

western Grand Canyon, about 150 mi and in a north-south 

direction approximately 60 mi.

The boundaries between formations, with the single 

exception of the Watahomigi-Manakacha contact, coincide with various key conglomerate beds that probably are 

approximate time planes. The boundaries between most of 

the units, in contrast, are surfaces between different rock 

types and, therefore, bear no relation to planes of time. 

The various sandstones, mudstones, and limestones thicken 

or thin in different directions, but most of them change 

facies very gradually. Only through a study of facies distribution, as discussed in chapter P, are many of these subtle differences detected.

Major trends in thickening and thinning of rock units 

and changes in facies commonly are attributed to distance 

from shore in marine deposits and to rates of sinking and 

changes in environment along the shore or inland from it. 

Most thickness and lithic changes in formations of the 

Supai Group can be explained by changes in the land-sea 

relations as shown on successive paleogeographic maps of 

the region (figs. D3, D4, D7, and D8). The Supai strata 

were deposited in an embayment bordering on a geosyncline to the west but periodically were connected with a 

seaway to the southeast and at other times with a seaway 

to the northeast. Thus, the embayment and its coastline 

were constantly changing shape and position.

Type sections

The type locality of the Supai Formation, now the Supai 

Group, was designated by N. H. Darton (1910, p. 25) as 

Havasu (Cataract) Canyon in the vicinity of Supai village. 

This locality, on the south side of Grand Canyon, includes 

excellent exposures of the red sandstone, limestone, and 

mudstone beds that constitute this group.

When strata of the Supai Formation were raised in 

rank to the Supai Group, the type section remained unchanged (McKee, 1975, p. J2), but the group was divided 

into four formations, each of which had its type section in 

the same general area (fig. C4).

The lowermost, or Watahomigi Formation, was named 

for Watahomigi Point on the west side of Havasu Canyon, 

about 1.5 mi northwest of Supai village; its type section is 

along the Hualapai Trail. The second formation above the 

base of the group, the Manakacha, was named from Manakacha Point on the east side of Havasu Canyon and 

directly above Supai village; its type section is along the 

Apache Trail. The third, or next to highest of the formations, was named the Wescogame from the point of that 

name on the west side of Havasu Canyon, about 3 mi 

southwest of the village, and it has its type section along
TABLE C2.—Thickness, in feet, of subdivisions of the Supai Group1

[Measured section number in parentheses. Dash (-) indicates no measurement]

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267.0 

615.5 710.0 344.0 124.5 76.0 106.0 130.5 197.5 378.0 317.0 316.5 - 786.5 446

Wolfcampian

c 

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Morrowan |Atokan

123.0 129.0 0.0 0.0 60.5 0.0 0.0 

231.5 203.0 335.5 247.5 302.5 26

184.5 191.5 245.5 221.0 195.5 232.0 224.0 

70.0 41.5 16.0 14.0 69.5 53.5 70.0 91.5 79.5 114.0 75.5 88.0 81

377.5 362.0 261.5 235.0 325.5 285.0 273.0 427.0 327.0 416.5 307.5 312.0 343

18.5 19.5 18.0 43.0 59.5 72.5 27.5 92.0 23.0 - 49.0 - 

98.5 

114.0 106.0 108.0 147.5 142.0 163.0 99.0 148.5 140.5 - 76.0 - 

98.5 132.5 125.5 126.0 190.5 201.5 235.5 126.5 240.5 163.5 - 125.0 - 

98.0 115.5 114.5 74.0+ 80.5 75.5 147.5 80.5 89.5 84.5 - 62.0 - 

95.0 115.5 108.5 - 114.0 218.0 190.5 150.5 255.5 179.0 - 164.0 - 

193.0 231.0 223.0 - 194.5 293.5 338.0 231.0 345.0 263.5 - 226.0 - 

25.5 - - 68.5 - 83.5 - - - 98.5 - 

25.0 - 

87.0 79.5 24.5 65.5 

57.0 - 

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Total Supai Group1 - 819.5 860.5 715.0 435.0+ 803.0 873.5 1005.0 950.5 1119.0 968.5 - 843.5 - 
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Group

Formation

Subdivision

Age

Canyon Tuckup (18) 

Canyon Mountain Blue (19) 

Valley Prospect (20) 

Valley Toroweap (21) 

Wash Whitmore (22a) 

Canyon Parashant (23) 

Canyon Andrus (24) 

Canyon Springs Twin (25) 

Cave Guano (26) 

Canyon Snap (27) 

Wash Pigeon (28) 

Mine Gulch Grand (29) 

Canyon Hidden (30a) 

Canyon Hidden (30b) 

Canyon Hidden (30c) 

Canyon Iceberg (31) 

Seligman (32) 

Canyon Separation (34) 

Canyon Hindu (35) 

AHdVHDIlVHlS QNV AOOIOHIH 
38 THE SUPAI GROUP OF GRAND CANYON

112°40'

36°15' rzfi

. . ay/Nauqjo 

Watahomigr/ f |Fa//s 

Point

FIGURE C4.—Havasu Canyon, Ariz., showing localities of type sections and geographic features used in naming the 

Watahomigi (Wa), Manakacha (M), and Wescogame (We) Formations and the Esplanade Sandstone (E).
STRATIGRAPHY AND LITHOLOGY 39

the Hualapai Trail. The uppermost formation was called 

the Esplanade Sandstone after the Esplanade Platform, a 

prominent bench that the formation forms in the walls of 

Havasu Canyon. The type section of the Esplanade was 

described from the east side of the Havasu Canyon, along 

the Apache Trail above Supai village (measured sec. 14).

The Watahomigi Formation

The Watahomigi is composed of three informal units: a 

lower slope unit, a middle cliff unit, and an upper slope

unit (fig. C5). The characteristic lithologic features and 

boundaries of each are described below.

The lower slope unit of the Watahomigi is dominantly 

red argillaceous mudstone and siltstone with a few thin 

units of aphanitic to granular limestone (peloidal wackestone and bioclastic wackestone). Beds of conglomerate at 

the base and within this unit include angular chert gravels 

of olive, gray, and brown, within a dark red-brown silt or 

sand matrix. The lower slope and middle cliff units probably intertongue or grade laterally from one to the other; 

the upper part of the lower slope mudstone of eastern

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FIGURE C5.—The Watahomigi and Manakacha Formations in Grand 

Canyon region, Arizona. A, Slope of Watahomigi, 196 ft thick, exposed in window formed by Holocene basalt flows, foot of Toroweap 

Valley; cliff of Redwall Limestone at bottom. 8, Watahomigi slope 

between cliffs of Manakacha, above, and Redwall, below; Havasu

Canyon. C, Slope of Watahomigi (bottom) overlain by cliff and slope 

units of Manakacha (center) and Wescogame cliff above; Snap Canyon. We, Wescogame Formation; M, Manakacha Formation; B, Holocene basalt flow; Wa, Watahomigi Formation; R, Redwall Limestone.
40 THE SUPAI GROUP OF GRAND CANYON

Grand Canyon seems to be a facies-equivalent of the middle cliff limestone of western Grand Canyon.

The middle cliff unit of the Watahomigi is a tongue of 

limestone that thins eastward and southeastward through 

Grand Canyon, and is absent in the Blue Springs area east 

of Grand Canyon. This thinning may have resulted from 

any of several factors: (1) a lateral facies change from limestone to red argillaceous mudstone that occurred progressively farther east with passage of time; (2) a thicker accumulation of limestone toward the deeper water in the west; 

or (3) progressively greater bevelling in the east, resulting 

from emergence of the land and westward regression of the 

sea. The upper contact of the middle cliff unit is flat and 

even in most places.

The upper slope unit of the Watahomigi has at its base 

the conglomerate informally referred to as the Atokan conglomerate because it is the lowest stratum of Atokan age. 

This conglomerate has been found in 14 of 25 measured 

sections. At the type section of the Watahomigi Formation 

this conglomerate contains fragments of jasper, associated 

with aphanitic limestone (lime mudstone) pebbles. In 

many localities, the upper slope unit of the Watahomigi is 

covered with talus from the cliff unit of the overlying Manakacha Formation, but, in general, this part of the Watahomigi can be recognized by its topographic expression, 

with a major cliff above. It consists largely of alternating 

beds of limestone and shaly siltstone or mudstone.

In eastern Grand Canyon, where limestone beds in the 

Watahomigi Formation are thin or absent, the middle cliff 

unit is not well developed, and the upper boundary of the 

formation is placed at the base of the first major cliff above 

the Redwall Limestone. Farther west, where the middle 

part of the Watahomigi forms a cliff, the upper boundary 

of the formation occurs at the bottom of the second major 

cliff. In addition to these topographic criteria, contact 

between the Watahomigi and the Manakacha commonly 

can be recognized by the occurrence of the first conspicuous sandstone beds; sandstone is characteristic of the 

lower part of the Manakacha Formation, but not of the 

Watahomigi.

Within the Grand Canyon region the Watahomigi 

Formation ranges in thickness from less than 100 ft in the 

southeast (Bunker Trail, Grandview Trail) to more than 

300 ft in the west (Iceberg Canyon, Hidden Canyon, 

Pigeon Wash). Differences in thickness of adjacent sections, as recorded (figs. C6A; A2-A8), may be, in part, the 

result of relief at the base, but also at some localities may 

be due to difficulties in recognizing the upper boundary.

In general, directions of thinning in the various units, 

especially the middle carbonate rock unit, seem to reflect 

the configuration of the embayment in which deposition 

occurred. Because the embayment was open only to the 

west (figs. D3, D9), a shoreward thinning to the south, 

east, and north resulted; mostly red siltstone and mudstone accumulated around the shoreward margins.

The Manakacha Formation

Unlike other formations of the Supai Group, the Manakacha attains its maximum thickness in the eastern part of 

Grand Canyon (figs. C6B; A2-A8) where strata are more 

than 300 ft thick at Kaibab and Hermit Trails. From this 

area, the formation thins in all directions, as indicated on 

the paleogeographic map (fig. D4). At the time (Atokan) of 

deposition the embayment seems to have been part of a 

passageway connecting the Cordilleran geosyncline to the 

west with the Paradox basin to the northeast and an absence of shorelines existed in both of these directions. The 

area of maximum deposition had shifted eastward from 

that of the preceding epoch.

The Manakacha consists of two units (figs. C3, C5): a 

(lower) cliff unit that is dominantly cross-bedded, calcareous sandstone and sandy limestone and an (upper) slope 

unit composed largely of shaly mudstone with minor 

amounts of limestone and sandstone. In northeastern 

Grand Canyon the two units have approximately the same 

thickness (table C2), but westward the cliff unit is progressively thicker at the expense of the slope unit above. From 

Kaibab Trail west to National Canyon, the cliff unit is 

about twice as thick as the slope unit, and still farther west 

it averages approximately three times as thick. Thus, the 

proportion of limestone and sandstone to mudstone is relatively much greater in the west than in the east.

The lower boundary of the Manakacha Formation is 

placed at the bottom of the sheer cliff formerly referred to 

as the lower cliff unit of the Supai (table Cl). This is a 

readily recognizable topographic feature, hence contributes to the formation being a mappable unit. Furthermore, 

sandstone beds commonly occur directly above this contact, but not in the Watahomigi slope below, so the sandstone constitutes a useful guide to the boundary. Irregular 

surfaces of erosion occur at the boundary on the Kaibab 

Trail, north, and in Havasu Canyon. Elsewhere the contact seems to be a flat, even surface.

The top of the Manakacha Formation is a widespread 

erosion surface characterized by many small to moderately 

deep channels. This channeled surface has been recognized 

in numerous places throughout the Grand Canyon region. 

The position of this upper boundary of the Manakacha 

can, in most places, be readily determined for mapping 

purposes as it is near the base of a major cliff (middle cliff 

unit, table Cl).

The Wescogame Formation

The Wescogame Formation is a tabular rock unit, ranging between 100 and 200 ft in thickness throughout most of 

the Grand Canyon area (fig. C7). Only in the southwestern 

part, at Guano Cave and at Separation Canyon, is its 

thickness less than 100 ft (figs. C6C; A2-A8). It is bounded
STRATIGRAPHY AND LITHOLOGY 41

FIGURE C6.—Thickness distribution (in feet) of formations in Supai Group, Grand Canyon region, Arizona. A, Watahomigi; 6, Manakacha; C, Wescogame; and D, Esplanade (including tongues of Pakoon Limestone of McNair, 1951).

both on top and bottom with surfaces of erosion in which 

channels are partly or entirely filled with conglomerates 

(table HI).

The basal conglomerate of the Wescogame Formation 

has been recorded in 14 measured sections. Although it 

forms a regular even bed, a few feet thick in most places, it 

fills channels to depths of 10, 11, and 15 ft at Bunker Trail, 

Toroweap Valley, and Thunder River Trail, respectively 

(figs. H7, H8, H10, J3). At some localities, neither channels 

nor conglomerate seem to be present at the base of the 

Wescogame, probably because of originally high terrane in 

interfluve areas.

Two units are recognized in the Wescogame, distinguished by composition and topographic expression. The 

lower, thicker unit is here referred to as the cliff unit and in 

earlier descriptions of the Supai was called (McKee, 1975) 

the middle cliff unit (table Cl). It is composed largely of 

cross-stratified, very fine grained sandstone. The upper 

unit is referred to in this publication as the slope unit, and 

in an earlier classification of the Supai was designated as 

the lower part of the upper slope unit (table Cl). It is composed mostly of alternating red-brown siltstone or mudstone beds and cross-stratified sandstone.

The cliff unit of the Wescogame ranges in thickness 

between 100 and 150 ft throughout most of eastern Grand 

Canyon (table C2). It is between 70 and 100 ft thick nearly 

everywhere in central and central western Grand Canyon, 

but more than 100 ft in the extreme western part.

The thin slope unit in the upper part of the Wescogame 

ranges in thickness betwen 20 and 70 ft throughout most of 

the region, but in sections of the northeast is slightly less 

than 20 ft thick.

An isopach map of the Wescogame Formation (fig. Dll) 

shows that the basin of accumulation was connected with 

seaways both to the west and the southeast. Current direction vectors (fig. K15A, B) suggest a principal source of 

detritus to the north.

The Esplanade Sandstone

Throughout the Grand Canyon region, the Esplanade 

Sandstone consists of two readily recognizable units; in 

many places, a third unit can be distinguished (fig. P12). 

From bottom to top these units are referred to by the informal terms of (1) basal slope unit, (2) main cliff unit, and
42 THE SUPAI GROUP OF GRAND CANYON

FIGURE C7.—The Wescogame Formation in Grand Canyon, Arizona. 

A, Large-scale tabular-planar cross-strata at top of cliff unit; slope 

unit above and main cliff of Esplanade Sandstone beyond; Thunder 

River Trail. 6, Massive unit of large-scale cross-strata with thinner 

beds below forming cliff unit of formation, slope unit above; Esplanade Sandstone cliff in upper left, Kaibab Trail, south. C, Cliff unit

(3) upper slope and ledge unit or upper cliff-slope unit. 

The bottom two are continuous throughout the region; 

the upper unit, recognized by alternating slopes and small 

cliffs, or receding ledges, is conspicuous along both eastern and western margins of the outcrop area and in the 

north-central part (figs. C8; P12). In the extreme western Grand Canyon region most of the lower part of the 

main cliff unit is represented by thick beds of carbonate 

rock, mostly dolostone, known as the Pakoon Limestone 

(McNair, 1951).

The basal slope unit of the Esplanade consists of alternating layers of sandstone and siltstone or mudstone, with 

limestone at a few localities (table C3). The thickness 

ranges from about 14 ft to a maximum of 130 ft, but across 

most of the area is between 50 and 100 ft (table C2). Much 

of the difference in thickness from place to place results 

from irregularities of the channeled erosion surface upon

and slope unit of Wescogame overlain by cliff formed by tongue of 

Pakoon Limestone of McNair (1951), Snap Canyon. D, Planar crossstrata, large-scale, in upper part of cliff unit; near Apache Trail to 

Havasu Canyon. W1, Wescogame cliff unit; W2, Wescogame slope 

unit; E, Esplanade Sandstone; P, Pakoon Limestone.

which deposition occurred. Channels 50 ft deep at Soap 

Creek, 47 ft at Havasu Canyon, and 45 ft at National Canyon indicate extremes in this erosion (table Hi). Because 

the deep channels are mostly in the central part of the region, maximum thicknesses of the unit are also in this area.

Most channels at the base of the formation are largely or 

entirely filled with gravel known as the basal conglomerate 

of the Esplanade. This conglomerate is the most persistent 

one within the Supai Group, and has been recorded from 

28 localities. Conglomerate beds, 15-17 ft thick, occur at 

four localities examined, and an erosion channel 35 ft deep 

was measured at Twin Springs Canyon. Characteristics 

and diagnostic features of this conglomerate are described 

and tabulated in chapter J.

A somewhat similar but less extensive and thinner conglomerate occurs higher in the basal slope unit at Havasu, 

National and S B Canyons and at Toroweap Valley, all in
FEET 

1000 -i

900-

800-

700-

600-

500-

400 - 300-

200-

100-

o -i to

EXPLANATION

Flat-bedded sandstone 

Cross-bedded sandstone Siltstone or mudstone 

Limestone and dolostone 

Gypsum 

Conglomerate

2S&29

y t°7

FIGURE C8.—Principal rock types represented in measured sections of Pakoon Limestone (McNair, 1951) and Esplanade Sandstone of Grand Canyon area, 

Arizona. Columns drawn to scale are, in general, from west (left) to east (right) and show erosion surfaces where recognized at top and bottom. Datum is base 

of Esplanade. A, Basal slope unit; 8, main cliff unit; and C, upper cliff-slope unit. Numbers refer to measured sections shown on figure A1.
44 THE SUPAI GROUP OF GRAND CANYON

TABLE C3.—Percentages of sandstone, mudstone, and carbonate rocks in principal units of Esplanade Sandstone1

[ss, sandstone; sh, mudstone; Is, limestone; dol, dolostone. Leaders (—) indicate not present]

Sec.

No.

2

3

4

4a

5

6

7

8

9

10

11

12

14

15

16

17

18

19

20

21

22

23

24

25

27

28

29

30

31

Locality

Twentynine Mile Canyon

Eminence Fault ...........

Blue Spring ..............

Horsetrail Canyon ..........

Bunker Trail ...............

Grandview Trail ..........

Kaibab Trail, south ........

Kaibab Trail, north ..........

Hermit Trail ...............

Bass Trail .................

Shinumo Trail .............

Thunder River Trail .........

Havasu Canyon ............

National Canyon ..........

Kanab Canyon .............

S B Canyon ...............

Tuckup Canyon ............

Blue Mountain Canyon ......

Prospect Valley ............

Toroweap Valley ...........

Whitmore Wash ...........

Parashant Canyon ..........

Andrus Canyon ............

Twin Springs Canyon .......

Snap Canyon ..............

Pigeon Wash ..............

Grand Gulch Mine .........

Hidden Canyon ............

Iceberg Canyon ............

Basal slope

ss

43

.

,

47

18

—

41

38

18

42

63

85

87

67

100

68

66

21

36

86

84

58

55

65

._

4

sh Is-dol

56 1

100

100

53

82

98 2

59

62

72 10

58

37

15

13

35

_.

32

34

73 6

43 21

14

16

42

45

35

...

72 24

(Not measured)

89

52

._

48

Main cliff

ss

96

89

83

84

80

74

76

83

84

85

79

100

100

87

90

91

87

70

100

100

100

100

85

81

2

_.

sh Is-dol

2 2

11

17

16

20

26

24

17

16

15

21

0

0

6 7

10

9

13

12 18

—

—

...

—

2 13

13 6

'98

6 J94

(Not Measured)

._

3

10 1 90

2 J95

Upper cliff-slope

ss

60

64

...

—

64

—

—

_.

...

...

—

...

100

...

—

...

—

_.

...

59

83

41

67

...

75

sh Is-dol

40

36

_.

—

36

—

_.

_.

_.

_.

—

...

_.

...

...

...

—

._

...

41

17

59

33

—

25

...

—

...

...

...

...

_.

._

...

_.

...

...

...

—

—

—

...

—

—

...

_.

—

—

—

._

(Not measured)

71

56

12

28

44

81

1

...

7

Includes Pakoon Limestone (McNair, 1951) where present.

central Grand Canyon, and at Whitmore Wash, Blue 

Mountain and Snap Canyons in the west. The significance 

of this upper conglomerate is not apparent, but probably 

marks the position of a local hiatus.

The main cliff unit of the Esplanade is the thickest and 

most distinctive unit of the formation as its name suggests 

(fig. C9). The thickness ranges from about 200 to 350 ft. 

This sandstone is characteristically thick bedded and crossstratified, but locally, especially in eastern Grand Canyon, 

it appears structureless in some sections. Everywhere it 

forms a massive, reddish-brown cliff of well-sorted quartz 

sandstone.

In the extreme western part of the Grand Canyon region, most of the main cliff unit, including all of its lower 

part, is represented by thick beds of carbonate rock, mostly 

dolomitic, known as the Pakoon Limestone (McNair, 

1951) (fig. P12). The Pakoon, according to McNair (1951, 

p. 524), might be interpreted as a wedge of carbonate rock, 

older than the Esplanade and thinning eastward under the 

Esplanade so that in measured sections along the east side 

of the Shivwits Plateau, as at Andrus Canyon, Parashant 

Canyon, Whitmore Wash, and other localities, it is absent

through nondeposition. Such an explanation probably is 

not correct, however, because sections farther southeastward at Twin Springs Canyon, Blue Mountain Canyon, 

and elsewhere, show tongues of Pakoon-like rock within 

the massive sandstone cliff. Furthermore, much of the 

sandstone of the Esplanade directly east of the Pakoon outcrops is very dolomitic, suggesting the continuation of an 

environment of concentrated marine waters into the area 

of sand deposition. Thus, the Pakoon is here considered to 

be an intertonguing facies equivalent to the lower part of 

the Esplanade Sandstone.

The uppermost unit (upper cliff-slope unit) of the 

Esplanade Sandstone is present in many stratigraphic sections (fig. P12). It contains a series of slope-forming siltstone or mudstone tongues or lenses within beds of massive 

sandstone and characteristically forms receding ledges or 

small cliffs separated by slopes and benches. The contact 

between this unit and the underlying main cliff unit is arbitrarily placed at the top of the massive sandstone or the 

base of the lowermost prominent slope. Because sedimentation apparently was continuous through this sequence 

of strata (main cliff-uppermost unit) and because no evidence of unconformity can be recognized between the two,
STRATIGRAPHY AND LITHOLOGY 45

^'"^S-'^^^v ¥\

£&vr.4il *\. ~ i ^^SJFj^fA-* '. ' *' ^f >ti,i* -^*^.^-fe«* *;, -^

b^.T ** ^ •. s^>?-^^:*:;r:t^,v ;

*/^- *s^.- «r I *-t.V«x :Xr^^/vJ^-, * -7V^".<, -«* ^ 

- «..«-.^ " > t*-- " *J* *• -*K * y •, *- • v~ -•« •' * "x* « " -• ^ --.*.^\ N»lv.4;^^e-V ,.: ~>- ^ .. - ^•- iJ-'^'-v.. "O^jsV^-* .-;:-^j.. : " '

--<-- * ^".

u^^-^^-^-^^J^'^*

FIGURE C9.—The Esplanade Sandstone in Grand Canyon, Ariz. A, Fishtail Canyon near Thunder River Trail; 8, Little Colorado River canyon at 

Blue Spring; C, along west trail to Thunder River; D, Parashant Canyon, view north; E, east side of Whitmore Wash, basalt flow to right. E, Esplanade 

Sandstone; W, Wescogame Formation; H, Hermit Shale; C, Coconino Sandstone; Tb, Tertiary basalt.
46 THE SUPAI GROUP OF GRAND CANYON

accurate extension of this boundary throughout the region 

cannot be made with any degree of certainty.

On the Shivwits Plateau in the northwestern part of the 

region (fig. P12) a gypsiferous facies consisting of bedded 

gypsum and gypseous fine-grained sandstone occurs above 

the massive sandstone of the main cliff unit, forming a 

weak unit between two resistant cliffs. These gypsiferous 

beds extend from Andrus and Parashant Canyons on the 

west to Toroweap Valley on the east and are considered a 

facies of the upper cliff-slope unit.

Fine-grained detrital rocks of the upper cliff-slope unit 

that are dominantly siltstones and mudstones overlie the 

carbonate rocks of the Pakoon Limestone in westernmost 

sections of the Grand Canyon area. These fine-grained 

strata apparently grade eastward or intertongue with relatively pure sandstone in the upper part of the Esplanade. 

The change in facies is well illustrated by comparing the section at Iceberg Canyon, where the upper cliff-slope unit is 12 

percent sandstone and 81 percent siltstone and mudstone, 

with the Snap Canyon section to the east with 75 percent 

sandstone and 25 percent siltstone and mudstone (table C3). 

A similar contrast exists in a north-south sequence of sections from Hidden Canyon to Snap Canyon, with ratios of 

56-44 percent and 75-25 percent, respectively.

The combined thickness of the Esplanade Sandstone and 

Pakoon Limestone increases from east to west. Westward 

from Snap Canyon to Iceberg Canyon a -distance of 50 

mi the thickness increases from 498.5 ft to 718 ft. Northwestward from Twin Springs Canyon to Hidden Canyon, 

approximately 45 mi, an increase from 419 ft to 856 ft is 

recorded (fig. C8). The most likely explanation for this 

marked thickness change at the outer edge of the northwestern Arizona embayment is an increased rate of downwarping with consequent greater deposition along the 

margin of a basin or geosyncline to the west. A decreasing 

degree of erosion from east to west at the termination of 

Esplanade deposition might also account for increasing 

westward thickening. However, the coincidence of a 

marked change in sediment type from chiefly sandstone of 

the Esplanade into carbonate rock of the Pakoon on the 

western edge of the area of thickening lends strong support 

to the former concept. To the east, high-energy crossbedded sands indicative of a high-energy environment contrast with the western low-energy carbonate deposits 

overlain by silts, representative of relatively quiet waters.

The upper boundary of the Esplanade is a surface of 

erosion and in many places contains narrow channels, of 

considerable depth, as noted by Noble (1922, p. 63-64). 

This eroded surface at the upper boundary is nowhere 

overlain by a conglomerate. Although this contact is 

conspicuous in most parts of eastern Grand Canyon, it has 

not been recognized in sections of the far west, such as 

those near Grand Wash Cliffs. The Esplanade Sandstone is 

covered by the Hermit Shale throughout the region.

LITHOLOGY

Lithology of the Watahomigi 

Formation

Rocks of the Watahomigi Formation in the Grand Canyon region are distinctive in that they consist almost entirely of mudstone and carbonate rock and include very 

little sandstone. Red mudstone is more common here than 

in any other formation of the Supai Group; the amount of 

carbonate rock ranges from about 15 percent in the east to 

as much as 90 percent locally in the west. The proportions 

of these rock types in the Grand Canyon region (fig. CIO) 

are shown by the following generalized percentages (figures 

show range in percent for each area):

West Central East

Sand ...................... 0 5-15 0-5

Mud ...................... 20-40 25-60 50-85

Carbonates ................. 60-90 30-40 15-35

Vertical sections of the Watahomigi Formation are 

readily divisible into three units in most localities of western Grand Canyon. The upper and lower divisions form 

slopes that are separated by a cliff in canyon profiles. Each 

slope consists largely of detrital beds mostly red mudstones and red siltstones and the cliff is formed largely of 

carbonate rock. Because the proportion of mudstone increases eastward as that of limestone decreases, the middle 

cliff unit becomes progressively smaller and weaker in that 

direction until it is a negligible topographic feature in most 

localities of eastern Grand Canyon.

Conglomerate forming thin beds and lenses constitutes a 

small but prominent part of the Watahomigi. In many 

places a distinctive conglomerate bed of durable pebbles 

and granules occurs at or near the bottoms of the lower 

and upper slope units, and in some places other conglomerate beds occur in the section, as at Toroweap Valley and 

at Havasu Canyon. The gravels are of resistant rock types 

such as flint and jasper and they commonly include indigenous marine fossils.

Lithology of the Manakacha 

Formation

The lithology of the Manakacha Formation differs greatly both from that of the underlying Watahomigi and from 

that of the overlying Wescogame. Considerably more 

sand, but somewhat less silt and mud, is contained in the 

Manakacha than in the Watahomigi as shown by figures 

CIO and Cll. Limestone is common in both, especially in
114°

STRATIGRAPHY AND LITHOLOGY

113°

47

112°

37C

36'

EXPLANATION 

SSSJ Sandstone

Carbonate rock 

Mudstone 

Concealed areas

FIGURE C10.—Vertical bar graphs indicating the proportion of sandstone, mudstone, carbonate rock, and concealed areas in measured sections of 

the Watahomigi Formation, Grand Canyon area, Arizona. The graphs show only the proportion of major rock types; no stratigraphic position is 

indicated. Numbers are those of measured sections (fig. A1).

the western sections. Much more carbonate sediment and 

less mud occurs in the Manakacha than in the Wescogame 

Formation (fig. C12). Sandstone, although common in 

both formations, constitutes nearly all of many Wescogame sections. Approximate proportions of each main 

type of sediment in the Manakacha are as follows (figures 

show range in percent for each Grand Canyon area):

West Central East

Sand ...................... 10-30 5-60 20-50

Mud ...................... 0-10 5-30 30-60

Carbonates ................. 35-90 15-75 5-20

Distinction of carbonate rock from sandstone in the 

Manakacha Formation is difficult in many places as a complete gradation occurs from sandy limestone to calcareous 

sandstone. Accurate determination of a rock's classification in such places can be made only through mechanical 

analysis. Sandstone comprises most of the upper part of 

the unit, whereas a large proportion of carbonate rock is in

the lower half. These lithologic differences between upper 

and lower parts of the unit may be indicative of a major 

environmental change and, near the midpoint in at least 

four sections S B, Tuckup, Parashant, and Snap Canyons a conglomerate overlying an erosion surface occurs 

in that stratigraphic position.

Mudstone is most abundant in the eastern localities and, 

to a lesser extent, in central localities; limestone is dominant in the west, but is also common through much of the 

central area.

Lithology of the Wescogame 

Formation

Lithofacies of the Wescogame Formation differ considerably from east to west across the Grand Canyon region 

(fig. C12). Although sandstone, mudstone, and carbonate 

rock are represented in most sequences their proportions 

are very different from place to place as shown below (figures show range in percent for each Grand Canyon area):
48

114°

THE SUPAI GROUP OF GRAND CANYON 

113° 112°

37C

36C

EXPLANATION 

I Sandstone

| [ Concealed areas

FIGURE C11.—Vertical bar graphs indicating the proportion of sandstone, mudstone, carbonate rock, and concealed areas in measured sections of 

the Manakacha Formation, Grand Canyon area, Arizona. The graphs show only the proportion of major rock types; no stratigraphic position is indicated. Numbers are those of measured sections (fig. A1).

West West-central

Sand .......... 10-50 70-100

Mud .......... 0-10 0

Carbonates .... 50-75 0-30

East-central East

75-90 50-65

10-25 20-35

Trace 0-10

Except in the extreme west where carbonate rock 

prevails, sandstone is the dominant rock, forming more 

than 50 percent of the measured sections. In some parts 

of central Grand Canyon, the Wescogame is exclusively 

sandstone. Farther east, considerable amounts of mudstone are present, whereas toward the west higher proportions of limestone occur. Limestone occurs in moderate 

amounts in a few eastern sections and may have been 

deposited in a seaway from the northeast (fig. D7) or have 

accumulated in local ponded areas, with no connection to 

the western sea.

Limestones and sandstones intertongue in rock sequences at Snap Canyon, Pigeon Wash, and Hidden Canyon along the Grand Wash Cliffs. At each locality, three 

or four cross-bedded sandstone units occur between thicker 

units of cross-bedded limestone. Eastward from this area

of intertonguing, as at Twin Springs Canyon, only one 

thin unit of limestone occurs. Westward from this area, at 

Iceberg Canyon, little sandstone is present.

Lithology of the Esplanade 

Sandstone

The Esplanade Sandstone throughout most of the Grand 

Canyon region is composed dominantly of uniform, very 

fine grained sandstone (fig. C13). This lithology represents 

from 60 to 90 percent of the formation; siltstone and mudstone forms most of the remainder. At many localities in 

central and eastern Grand Canyon, mudstone forms a 

large part of the basal slope unit above a pre-Permian erosion surface; farther west, and also northeast, mudstone 

occurs above the main massive sandstone cliff as well. The 

percentage of mudstone in these areas ranges from 10 

to 35. At Andrus and Parashant Canyons and at Toroweap Valley, numerous beds of gypsum occur within the 

sandstone-mudstone sequence of the upper cliff-slope unit.
114°

STRATIGRAPHY AND L1THOLOGY

113°

49

112°

37C

36C

EXPLANATION 

::.l Sandstone

Carbonate rock

Mudstone

Concealed areas

FIGURE Cl2.—Vertical bar graphs indicating the proportion of sandstone, mudstone, carbonate rock, and concealed areas in measured sections of 

the Wescogame Formation, Grand Canyon area, Arizona. The graphs show only the proportion of major rock types; no stratigraphic position is 

indicated Numbers are those of measured sections (fig. A1).

In all sections along the Grand Wash Cliffs of extreme 

western Grand Canyon and in Iceberg Canyon farther 

west, the position of the lower half of the Esplanade is occupied by dolomitic carbonate rock of the Pakoon Limestone. Apparently an abrupt lateral change westward in 

lithologic facies takes place through intertonguing of the 

Pakoon with the Esplanade. It occurs in a relatively short 

distance between sections at Twin Springs Canyon, Andrus Canyon, and others in westernmost Grand Canyon 

where the Pakoon is present.

A few thin tongues of carbonate rock, apparently from 

the Pakoon, extend far eastward through the Esplanade 

Sandstone of west-central and central Grand Canyon. 

These limestone tongues are recognized at Twin Springs 

Canyon in both the basal slope and main cliff units of the 

Esplanade and occur at Blue Mountain Canyon, Whitmore 

Wash, National, and Havasu Canyons near the base of the 

main cliff unit. In most, if not all, of these places, however, 

the limestone tongues represent less than 5 percent of the 

total lithology of the Esplanade.

Intertonguing of sandstone and mudstone is well developed in the area of east-central and eastern Grand Canyon. 

Through much of this area, thin mudstone units occur 

in the basal slope unit. At Hermit, Kaibab, south, and 

Grandview Trails, and at some other localities in the 

eastern area, mudstone beds alternate with sandstone beds 

in the upper part of the main cliff unit and in the basal 

slope unit of the Esplanade, apparently the result of interfingering between two facies. The main part of the formation in this area is a massive cross-bedded sandstone with 

little or no mudstone.

Very fine grained sandstone composes most of the sets 

and cosets throughout the formation, including the main 

cliff unit (fig. C8, table C3). A considerable amount of siltsize quartz is distributed throughout the region, mostly as 

siltstones in the upper and lower units or mixed with mud 

in beds of mudstone. Quartz sand of fine grain size has 

been determined for one or two samples from each of 15 

localities and sand of medium grain size for 7 localities. 

Sand particles of the larger sizes are mostly concentrated in 

a relatively few strata, indicating that sorting is good 

throughout the formation.
50

114°

THE SUPAI GROUP OF GRAND CANYON

113° 112°

37C

36°

EXPLANATION 

:??•¥: Sandstone

Carbonate rock

Mudstone 

Concealed areas

0 10 20 30 MILES

i . I_____I______I

FIGURE C13.—Vertical bar graphs indicating the proportion of sandstone, mudstone, carbonate rock, and concealed areas in stratigraphic sections of the Esplanade Sandstone and Pakoon Limestone (McNair, 1951). The graphs show only the proportion of major rock types; no 

stratigraphic position is indicated. Numbers are those of measured sections (fig. A1).

The Pakoon Limestone in the far west contains both 

relatively pure limestones and relatively pure dolostones, 

but some intermediate mixtures of calcium and magnesium 

carbonate are present. In marginal areas bordering the 

Esplanade Sandstone on the west, however, dolostone is 

the dominant rock type in the Pakoon.

REFERENCES CITED

Darton, N. H., 1910, A reconnaissance of parts of northwestern New 

Mexico and northern Arizona: U.S. Geological Survey Bulletin 435, 

88 p.

Longwell, C. R., 1921, Geology of the Muddy Mountains, Nevada, with 

a section to the Grand Wash Cliffs in western Arizona: American 

Journal of Science, 5th ser., v. 1, no. 1, p. 39-62.

McKee, E. D., 1975, The Supai Group Subdivision and nomenclature, 

in Contributions to stratigraphy: U.S. Geological Survey Bulletin 

1395-J, p. J1-J11.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern Arizona: American Association of Petroleum Geologists Bulletin, v. 35, 

no. 3, p. 503-541.

Noble, L. F., 1922, A section of the Paleozoic formations of the Grand 

Canyon at the Bass trail: U.S. Geological Survey Professional Paper 

131, p. 23-73.
THE SUPAI GROUP OF GRAND CANYON

PALEOGEOGRAPHY

Chapter D 

By EDWIN D. McKEE

Contents

Structural framework tor the Supai Group ..................

Defiance positive element . . . . . ..................

Piute positive element . ..........................

Kaibab uplift—A questionable element ..................

Ensenada land ........ ..........................

Cordilleran negative belt ......................

Sonoran geosyncline ......... ................

Arizona sag ..,,,,,,,, ..............................

Paradox basin ........................................

Black Mesa sag . . . . . ...................

Paleogeography of the Supai Group ..........................

Paleogeography of Watahomigi Formation .................

Paleogeography of Manakacha Formation .................

Paleogeography of Wescogame Formation ................

Paleogeography of Esplanade Sandstone ................

Correlation with strata of adjoining areas ......................

Correlation with strata of central Arizona . . ....

Correlation with strata to west and northwest of Grand Canyon

Correlation with strata of the Four Corners area ..... 

References cited .........................................

Page

53

53

53

55

55

55

56

56

56

57

57

57

65

66

67

69

69

70

72

72

51
52 THE SUPAI GROUP OF GRAND CANYON

Illustrations

FIGURE D1. Map showing general tectonic provinces in the Arizona region during Pennsylvanian

and Early Permian time ........... . . . . ...... 53

D2. Cross-sections showing alternative interpretations of ages and extents of Permian

strata, Fort Defiance area, Arizona and New Mexico ........................ 54

D3-D8. Regional paleogeographic maps for:

D3. Morrowan time ................................................. 59

D4. Atokan time . . ..... ....................................... 60

D5. Des Moinesian time ........................................... 61

D6. Missourian time . .........,,..,.......,.,.,..>.,....- 62

D7. Virgilian time . .....,.,,,,.,,.,.,..,.....,,...,.,.-........... 63

D8. Wolfcampian time ............................................... 64

D9-D12. Isopach maps, Grand Canyon region, of:

D9. Watahomigi Formation . . ............................ 65

D10. Manakacha Formation . . ....................................... 66

D11. Wescogame Formation ................. 67

D12. Esplanade Sandstone ............ ............................. 68

D13. Map of fossil localities in Mogollon Rim area, south and southeast of Grand Canyon, Ariz. .............................. 69

D14. Index map of fusulinid localities cited in table D4 ............................ 71

Tables

Page

TABLE D1. Terminology that has been applied to the Defiance, Defiance-Zuni, and related

positive elements ....... . ...... .... ..... ... 54

D2. List of paleogeographic maps showing area of Supai Group and related features ..... 58

D3. Faunal assemblages from Pennsylvanian well samples in Four Corners area .......... 65

D4. Comparison of fusulinids of Grand Canyon with those of southern Nevada and

California ............................................................. 71
PALEOGEOGRAPHY 53

STRUCTURAL FRAMEWORK 

FOR THE SUPAI GROUP

Throughout Pennsylvanian and Early Permian time the 

region of Arizona and adjoining states consisted of three, 

possibly four, areas that were consistently positive, two 

negative belts or geosynclines, one roughly circular basin, 

and two intermittently negative connecting passages or 

sags (fig. Dl). These features largely controlled the distribution of lands and seas, with constantly fluctuating 

positive or negative trends.

Defiance positive element

A positive element, located in the northeastern part 

of Arizona near Fort Defiance on the New Mexico border, 

probably was the most persistent elevated area within the 

state and certainly the most widely recognized through the 

Paleozoic. Its structural characteristics were first noted 

by Gregory (1917, p. 18), who described an outcrop in 

Quartzite Canyon as "a monadnock of a pre-Cambrian 

erosion surface an elevated mass which outlived its contemporaries through Cambrian, Silurian, Devonian and 

early Carboniferous time, only to be itself buried by the 

streams of Permian time." The irregular surface of quartzite was covered by Permian "chocolate-colored and red 

arenaceous shales" (Gilbert, 1917, p. 17).

Pfcte 

positive 

^ lemerst

UTAH 

ARIZONA

Ensenada land 

positive element

FIGURE D1.—General tectonic provinces in the Arizona region during 

Pennsylvanian and Early Permian time. Note position of Supai 

embayment.

Further description of the physical character of the Defiance uplift at the time of its initial burial in the Permian is 

furnished by Darton (1925, p. 85-86), who stated that the 

old quartzite surface contains "depressions and knobs, 

some of them 50 ft or more in height" that in some places 

are overlain directly by red sandy shale, but elsewhere are 

covered by "local masses of conglomerate *** consisting of 

angular masses of quartzite and a few boulders of limestone in a red sandy matrix."

The Zuni uplift to the southeast, as described by Darton 

(1925, p. 86) also exhibits an onlapping relation between 

the Precambrian basement and the covering of Permian 

red beds. This contact is similar to that near Fort Defiance, 

Ariz., but at Zuni the Precambrian rocks are granite and 

the overlying Permian contains near its base a limestone 

with "many Manzano fossils." Although the Defiance and 

Zuni uplifts are separated by an area of upper Paleozoic 

sediments, they have similar histories and are both relatively small, so they are commonly referred to by a compound name as though parts of a single positive element.

The Defiance or the Defiance-Zuni area, although recognized as a positive element by nearly all geologists concerned with the paleogeography of the region, has been 

described under a myriad of names. This lack of consistency is illustrated by a compilation from the literature 

(table Dl) that shows three variations in terminology for 

Defiance, two for Zuni, and nine for the combination of 

Defiance, Zuni, and other elements supposed to be parts of 

a single original feature.

Various opinions have developed concerning the time of 

burial and the nomenclature of onlapping Paleozoic strata 

on the Defiance positive element. This is primarily because, 

with a different sequence of formation names in the basin 

on each flank of the positive element, multiple correlations 

and different age assignments have been proposed. 

Whether the highest parts of the Precambrian surface were 

finally buried in Wolfcampian or in Leonardian time has 

been interpreted in more than one way as shown in northsouth sections (fig. D2). In any event, the positive element 

does not seem to have been "elevated as a highland or 

mountain area" at any part of the Pennsylvanian or Permian and few conglomerates or arkoses developed from it 

(McKee, 1951, p. 488). The general lack of relief or elevation during this time was discussed by Brew (1965, p. 102) 

and by Havener and Pye (1958, p. 78, 79).

Piute positive element

Positive elements seem to have prevailed throughout 

much of southern Utah during Pennsylvanian and Early 

Permian time. Localized positive elements comparable to 

the Defiance in Arizona have been postulated in various 

parts of this area. Among these are the Emery uplift of central Utah (Eardley, 1962, p. 74, fig. 6.7; Wengerd and
54 THE SUPAI GROUP OF GRAND CANYON

TABLE D1.—Terminology that has been applied to the Defiance, Defiance-Zuni, and related positive elements

Terminology Date Author, reference

Defiance uplift ..............

Defiance positive area .......

Defiance positive element .....

Zuni uplift ..................

Zuni positive element .......

Zuni-Defiance positive area ....

Zuni-Defiance platform .......

Zuni-Defiance uplift ..........

Zuni-Defiance arch ....

Defiance-Zuni area .........

Defiance-Zuni uplift ..........

Defiance-Zuni positive elements

Kaibab-Zuni uplift ...........

Piute-Zuni-Defiance platform . .

1957 Brown and Lauth, p. 153.

1958 Havener and Pye, p. 79, fig. 1; p. 80, fig. 2; p. 81, figs. 3, 4.

1962 Baars, p. 162, fig. 4.

1963 Brill, p. 308, fig. 1.

1951 McKee, p. 484.

1959 Pye, p. 5.

1960 Elston, p. 35.

1967 McKee and Oriel, and others, p. 204, fig. 72.

1969 McKee, p. 42, fig. 18.

1975 McKee and Crosby, and others, fig. 65.

1962 Eardley, p. 74, fig. 6.7.

1962 Baars, p. 162, fig. 4.

1967 McKee and Oriel, and others, p. 204, fig. 72.

1975 McKee and Crosby, and others, fig. 65.

1957 Sabins, p. 484.

1972 Mallory, p. 119, fig. 7.

1965 Brew, p. 99, fig. 11.

1962 Kottlowski and Havenor, p. 79.

1971 Irwin, p. 1977, fig. 1.

1958 Havenor and Pye, p. 78, 79.

1972 Hiteand Cater, p. 133.

1969 McKee, p. 42, fig. 18.

1975 McKee and Crosby, and others, fig. 15.

1965 Lessentine, p. 2013.

1972 Mallory, p. 117, fig. 6.

South

•ABOUT 160 MILESNorth

San Andres Limestone

Defiance 

positive element

San Andres Limestone

Defiance 

positive element

FIGURE D2.—Alternative interpretations of ages and extents of Permian strata in Fort Defiance area, Arizona and New Mexico. A, Wolfcampian

age; B, Leonardian age. Modified from McKee and Oriel, and others (1967, fig. 77).
PALEOGEOGRAPHY 55

Matheny, 1958, fig. 17; Baars, 1962, p. 162, fig. 4; Brill, 

1963, p. 308, fig. 1; Rich, 1971, p. 446, fig. 11; Hite and 

Cater, 1972, p. 133) and the Circle Cliffs uplift farther 

south in central southern Utah (Eardley, 1962, p. 74, fig. 

6.7; Heylmun, 1958, p. 1798, fig. 3). A third localized positive element, referred to as the Sevier uplift (Brill, 1963, 

p. 308, fig. 1), is shown questionably in west-central Utah. 

A broad weakly defined positive area covering much 

of southwestern Utah and including some or all of the three 

elements just described is apparent on most isopach maps 

of the region. This entire area, bordered by the Cordilleran 

geosyncline on the west and the strongly negative Paradox 

basin on the east, has variously been referred to as the 

west-central Utah uplift (Steele, 1959, p. 3-7), the central 

Utah high (Brill, 1963, p. 308, fig. 1), the western Utah 

high (Coogan, 1964, p. 488, fig. 1), the (southwestern 

Utah) platform (McKee and Oriel, and others, 1967, 

p. 204, fig. 72), the Piute platform (Mallory, 1972, p. 115, 

126, figs. 4, 9), and the Piute positive element (McKee and 

Crosby, and others, 1975, fig. 15).

Kaibab uplift—

A questionable element

The name "Kaibab uplift" seems to the writer to be an 

unfortunate choice of name for a positive element in Pennsylvanian time, despite the fact that a number of authors 

have used it. Some geologists (Havener, 1958; Baars, 1962, 

fig. 4; Hite and Cater, 1972, p. 133) have applied it to a 

supposed positive element located during the Pennsylvanian in the position of the present Kaibab uplift (fig. Al, 

near sec. 8). This concept seems untenable, however, in 

view of the amount of sediment deposited in that area 

during Morrowan, Atokan, Virgilian, and Wolfcampian 

time, shown in isopach maps of formations in the Supai 

Group (figs. D9-D12). This area did not exhibit positive 

tendencies like those of the Defiance and Zuni uplifts, 

during Pennsylvanian and Early Permian time, and apparently sank at least as much as several adjacent shelf areas.

Some authors, on the other hand, have used the name 

Kaibab uplift for areas well removed from the present geographic position of the Kaibab Plateau, and this usage likewise seems misleading. The name has been applied to an 

area in the middle part of southern Utah (Brill, 1963, fig. 1; 

Rich, 1971, p. 446, fig. 11), to the eastern part of southern 

Utah, northeast of Kanab, Utah (Heylmun, 1958, p. 1801- 

1802, fig. 3), and to an area in southern Utah northwest of 

the present Kaibab uplift (Brew, 1965, p. 99, fig. 11). That 

movements in these areas may have been ancestral to the 

present Kaibab uplift does not seem to be supported by 

their geographic positions, which show no relation to 

those structures that control the Kaibab uplift of today.

Ensenada land

The name Ensenada land was used by Schuchert (1910) 

for a supposed landmass in or near the southwestern corner 

of Arizona. Rather scant evidence, consisting of thickness 

trends from northeast and east across southern Arizona, is 

available to support this concept of a Paleozoic positive 

element. A thinning of Pennsylvanian rocks toward that 

area suggested to McKee (1951, p. 485, pi. 1-2) that a persistent landmass probably existed. Little evidence concerning the position, extent, or elevation of this positive 

element has become available with subsequent work on 

Pennsylvanian strata of the region (McKee and Oriel, and 

others, 1967; McKee, 1969, p. 42, fig. 18; McKee and 

Crosby, and others, 1975, figs. 15, 65), but it still seems 

likely that a landmass existed during the time of deposition 

of the Supai Group.

Cordilleran negative belt

In southern Nevada and westernmost Utah, the strongly 

negative belt, commonly referred to as the Cordilleran 

miogeosyncline, had pronounced negative tendencies in 

various places during late Paleozoic time (Brill, 1963, 

p. 312). The region west and northwest of the Grand Canyon area, therefore, has been variously referred to as the 

Cordilleran geosyncline (McKee, 1951, p. 490; Havener 

and Pye, 1958, p. 78; Pye, 1959, p. 5; Brew, 1965, p. 99, 

fig. 11; McKee and Oriel, and others, 1967, p. 204, fig. 72; 

Irwin, 1971, p. 1977, fig. 1), the Cordilleran trough 

(McKee, 1969, p. 42, fig. 18), and the miogeosyncline 

(Welsh, 1959, p. 87, fig. 12; Bissell, 1960, p. 1426; Coogan, 

1964, p. 487; McKee and Crosby, and others, 1975, 

figs. 15, 65).

Because during Pennsylvanian and Permian time the 

areas of rapid sinking were more localized and less uniform 

than in earlier parts of the Paleozoic, some geologists have 

considered the Cordilleran negative belt to be divisible into 

two or more basins separated periodically by less negative 

or by positive areas. The southernmost basin or basins 

west of the area of Supai deposition have been referred to 

as the Pioche basin (Brill, 1963, p. 308, fig. 1), the Ely 

basin and Bird Spring basin (Coogan, 1964, p. 488, fig. 1), 

the Hogan basin (Rich, 1971, p. 446, fig. 11), the Ely-Bird 

Spring basin (McKee and Crosby, and others, 1975, fig. 

15), and simply the basin (Welsh, 1959, figs. 8, 9, 10).

The southern Nevada basins probably were not continuously active throughout Pennsylvanian-Permian time; 

the Ely basin, for example, subsided principally in Early 

Pennsylvanian (late Morrowan) time, according to 

Coogan (1964, p. 488), but during the Late Pennsylvanian 

much of that area was included in the western Utah high. 

Thus, the conclusion is reached by Coogan that "both
56 THE SUPAI GROUP OF GRAND CANYON

basinal and mildly positive elements of less than systemic 

duration appear to have existed in the same part of the 

Cordilleran miogeosyncline during the Late Paleozoic."

An attempt to delineate within narrow limits a boundary between the "basin" with thick sections and the adjoining "platform" or shelf with relatively thin sections has 

been made by Welsh (1959, figs. 1, 12). This line of demarcation he has termed the "Las Vegas Hinge Line" (1959, 

p. 88). As pointed out by Brill (1963, p. 312), however, 

"this relatively rapid change in thickness and facies may be 

an illusion created through shortening caused by Cretaceous thrust faulting." Numerous examples of thrusting 

and consequent shortening of magnitudes ranging from 20 

miles (Longwell, 1949, p. 924) to 40 miles (Misch, 1957) 

have been recorded and were summarized by Brill for 

various areas along the Las Vegas line.

The part of southern Nevada, directly west of the Supai 

depositional area and southeast of the Cordilleran basins, 

has been referred to as the Callville shelf by Coogan (1964, 

fig. 1) and the Bird Spring carbonate shelf by Rich (1971, 

fig. IDSonoran geosyncline

A negative belt persisted in southeastern Arizona during 

all of Paleozoic time, but was especially active in the Pennsylvanian. It appears as a prominent feature on isopach 

maps of the region and is generally recognized as the 

northern end of a geosyncline that trended northwestward 

into Arizona from Mexico (fig. Dl). Commonly it is referred to as the Sonoran geosyncline (McKee, 1951, p. 485; 

Wengerd and Matheny, 1958, fig. 14; Pye, 1959, p. 5; 

McKee and Crosby, and others, 1975, p. 5, fig. 65), but it 

has also been called the Mexican geosyncline (Havener and 

Pye, 1958, p. 80) and the Sonoran trough (McKee, 1969, 

p. 42, fig. 18).

The Arizona part of the Sonoran geosyncline is considered a basin by some geologists and is called the Pedregosa basin by Brew (1965, p. 99, fig. 11) and by McKee 

and Oriel, and others (1967, p. 204, fig. 72). It is referred 

to as the Quemado-Cuchillo basin by Irwin (1971, p. 1977, 

fig- 1).

Arizona sag

The record of epeirogenic activity in central Arizona 

during Paleozoic time has long been a matter of controversy. Uncertainty concerning this activity has been caused 

partly because the sedimentary record is sparse, Paleozoic 

strata having been largely removed by erosion, and partly 

because the region apparently fluctuated between positive 

and negative movements. The history of this area has necessarily been deduced largely by projection of isopach 

trends and other data from adjacent areas.

To the northwest and southeast were geosynclines, and 

to the northeast an extensive basin, all of which sank considerably during Pennsylvanian and Early Permian time. 

Positive elements that remained constantly above sea 

level, though they were not elevated to great heights 

during this time, were to the north, east-northeast, and 

probably also southwest. However, the central Arizona 

area had neither the strongly negative tendencies of the 

geosynclines and basins, nor the consistently positive 

character of the positive elements.

Because of its intermediate character, central Arizona 

at times formed a barrier to adjacent seas and at other 

times was covered by shallow water, so it has been considered a positive area by some geologists and negative by 

others. Periods of elevation in this area were emphasized 

by Stoyanow (1936, p. 462; 1942, p. 1273-1274), and by 

Huddle and Dobrovolny (1945) who referred to it as 

Mazatzaland during Paleozoic time. Evidence of 

submergence and connecting seaways across this area have 

caused others (McKee, 1951, p. 485-486; 1969, p. 42; 

Eardley, 1951, pis. 7, 8, 9; 1962, figs. 6.7, 6.8) to minimize 

its positive character. Accordingly, it has been referred to 

as the Arizona sag (fig. Dl), periodically connecting seas 

of the Cordilleran and Sonoran geosynclines.

The Arizona sag seems to have been a marine barrier 

during Early Pennsylvanian (Morrowan) and Middle 

Pennsylvanian (Atokan) time, as illustrated by isopach 

lines on figures D3 and D4. During all of this time, the 

seaway occupying the Sonoran geosyncline probably was 

cut off from the embayment of the Cordilleran geosyncline 

that covered the Grand Canyon area. Not until Late Pennsylvanian (Virgilian) time is there good evidence that 

the sea extended completely across Arizona from northwest to southeast (fig. D7). Thickness trends on both sides 

(fig. D8) indicate that seas of two geosynclines probably 

connected across the Arizona sag again in Early Permian 

(Wolfcampian) time, but evidence for this event is not 

conclusive.

Paradox basin

Northeast of the area of Supai deposition in the Grand 

Canyon region, the Paradox basin of southwestern Colorado and southeastern Utah was actively sinking during 

much of Pennsylvanian and Early Permian time. The basin 

axis paralleled the southwest side of the Uncompahgre uplift in Colorado, and the basin margins extended southwestward into Arizona and New Mexico. The basin was 

about 360 miles from northwest to southeast and 180 miles 

at right angles.

The Paradox basin began to develop in Atokan time (fig. 

D4), when deposits a few hundred feet thick accumulated 

in both southwestern Colorado and southeastern Utah 

(Wengerd and Matheny, 1958, fig. 14) on a karst surface of
PALEOGEOGRAPHY 57

Mississippian rocks. Maximum subsidence of the Paradox 

basin was reached during Des Moinesian time, when 

several thousand feet of sediment were deposited and thick 

salt deposits accumulated in evaporitic seas. The depositional area at that time was widespread and connected 

westward across central Utah with the Cordilleran geosyncline and southward through western New Mexico with 

the Sonoran geosyncline (fig. D5).

Later in Pennsylvanian time sediments accumulated at a 

relatively slow rate and evaporitic deposition ceased, but 

the basin margins continued to be widespread. In Virgilian 

time connections with the Grand Canyon area, as well as 

in other directions, resulted from further submergence. By 

Wolfcampian time the basin configuration had greatly 

changed and the term "San Juan Basin" commonly is applied to the negative parts of this area.

Black Mesa sag

Black Mesa sag is the name used by Wengerd and Matheny (1958, p. 2082, fig. 17) for a marine embayment, extending southwestward from the Paradox basin, that subsided during Missourian time. This area in northeastern 

Arizona, roughly between Kayenta and Chinle, apparently 

was submerged also during parts of Atokan (fig. D4), 

Virgilian (fig. D7), and Wolfcampian times (fig. D8), and 

at those times formed a strait connecting with marine 

waters of the Grand Canyon region. Relatively thin deposits of sediment were accumulated in the Black Mesa 

sag, suggesting that the term "sag" is much more appropriate than "Black Mesa basin," which has commonly been 

used (for example, Lessentine, 1965, fig. 12).

PALEOGEOGRAPHY OF 

THE SUPAI GROUP

Because strata of the Supai Group range in age from 

Early Pennsylvanian into Early Permian and were formed 

during a number of widely separated intervals of time, 

they represent numerous distinct combinations of land-sea 

relationships. Generalizations regarding marine distribution are, therefore, difficult to make, although throughout 

this time some features remained constant, as indicated by 

the preceding discussion of the structural framework.

A general agreement occurs in the recognition of a 

continuously positive element east of the Grand Canyon 

embayment, along the Arizona-New Mexico border, and 

in the existence of major negative areas to the west in 

Nevada, to the northeast in the Paradox basin area, and in 

southeastern Arizona. Interpretations of minor physiographic features, however, differ greatly. As shown in 

table D2, more than 40 different paleographic maps of this

region, mostly isopach and lithofacies, have been published during the period between 1949 and 1978. These 

maps represent a wide variation in viewpoints.

In connection with the present investigation, a series of 

maps showing land-sea relations within Arizona and parts 

of adjoining states has been prepared for Pennsylvanian 

and Early Permian time (figs. D3-D8). These maps are 

largely derived from the isopach maps of the Pennsylvanian and Permian volumes of the Paleotectonic Map series, 

U.S. Geological Survey (McKee and Oriel, and others, 

1967; McKee and Crosby, and others, 1975). Details of the 

Supai embayment, in which the Supai Group was formed, 

however, were established directly from stratigraphic 

section measurements obtained at the 35 control stations 

studied in connection with this project.

Maps showing, in detail, configuration of the Supai embayment during development of each of the four formations of the Supai Group have been prepared as isopach 

maps (figs. D9-D12). Actually these maps delimit the 

boundaries of areas, both continental and marine, in 

which deposition occurred and are not strictly representative of land-sea margins; their isopachs indicate 

thicknesses of continental and marine deposits combined. 

As will be shown later, however, the proportion of continental sediments to that of marine apparently was so 

small that for general considerations the depositional 

limits, as established, serve to indicate approximate 

boundaries of the seaways.

Paleogeography of 

Watahomigi Formation

Paleogeography of the Watahomigi Formation is reconstructed primarily from the record of land-sea relationships in the Grand Canyon region during Morrowan time, 

and a small part of Atokan time. Throughout this interval 

the environment of deposition apparently was relatively 

constant in the area. The nearest main seaway was to the 

west in the Cordilleran miogeosyncline of Nevada. The 

Grand Canyon area was a shallow embayment with landmasses on three sides, as indicated by isopachs (fig. D3).

To the northeast of the Grand Canyon area, along the 

southern margin of the Paradox basin, no fossils of certain 

Morrowan age have been reported from Pennsylvanian 

rocks (table D3). Apparently at that time the Paradox sea 

was much restricted and was limited to areas farther east 

and north in Colorado and Utah; no marine connections 

from those directions to the Watahomigi embayment could 

have existed.

Eastward from the Grand Canyon area was the Defiance 

positive element with its center along the New Mexico 

boundary (McKee, 1951, p. 491). It, like the region farther 

north, seems to have been an area of nondeposition during
58 THE SUPAI GROUP OF GRAND CANYON

TABLE D2. Paleogeographic maps that show area of Supai Group and related features

Date

1962

1951

1957

1958

1958

1958

1958

1959

1959

1962

1963

1964

1965

1967

1971

1972

1972

1975

Author

Eardley ......................

McKee ......................

Sabins ........................

Brown and Lauth ...............

Wengerd and Matheny ..........

Havener and Pye ...............

Heylmun .....................

Welsh ........................

Steele ........................

Baars ........................

Brill .........................

Coogan ......................

Lessentine ....................

McKee and Oriel, and others

Rich .........................

Mallory ......................

Rascoe and Bailey ..............

McKee and Crosby, and others

Reference

fig. 6.7

fig. 6.8

pi. 2, fig. A

pi. 2, fig. B

fig. 11

p. 156, Exhibit

VII

fig. 14

fig. 15

fig. 16

fig. 17

p. 80, fig. 2

p. 81, fig. 3

p. 81, fig. 4

p. 1 798, fig. 3

p. 76, fig. 8

p. 79, fig. 9

p. 82, fig. 10

pi. 3

pi. 4

pi. 5

pi. 6

pi. 7

pi. 8

p. 162, fig. 4

p. 310, fig. 4

p. 310, fig. 5

p. 311, fig. 6

p. 311, fig. 7

p. 311, fig. 8

p. 488, fig. 1

p. 2010, fig. 12

p. 204, fig. 72

p. 446, fig. 1 1

p. 116, fig. 5

p. 117, fig. 6

p. 119, fig. 7

P. 120, fig. 8

p. 121, fig. 9

p. 1 50, fig. 5

pi. 15A

pi. 15A

pi. 15B

pi. 15B

pi. 15C

Title

Thickness and paleogeographic map, Pennsylvanian.

Thickness and paleogeographic map, Permian.

Isopach map, Pennsylvanian.

Isopach map, Permian.

Major late Paleozoic tectonic elements.

Northern Arizona isopach map, Pennsylvanian.

Thickness of pre-Paradox Pennsylvanian rocks.

Thickness of Paradox Formation.

Thickness of middle Paradox strata.

Thickness of Honaker Trail Formation.

Distribution of Morrowan seas.

Distribution of Des Moinesian seas.

Distribution of Virgilian seas.

Net Pennsylvanian and Wolfcampian carbonates.

Pennsylvanian isopachous and lithofacies map (Callville and Bird Springs

Formations).

Lower Wolfcamp isopachous and lithofacies map (Pakoon-Red SiltstoneLower Apex).

Middle and upper Wolfcamp isopachous and lithofacies map (Queantoweap, Hermit, Upper Apex).

Morrowan series isopachous map.

Atokan series isopachous map.

Des Moinesian series isopachous map.

Missourian series isopachous map.

Virgilian series isopachous map.

Wolfcampian series isopachous map.

Areal variations of Permian-Pennsylvanian boundary.

Isopach and lithofacies map, Morrowan.

Isopach and lithofacies map, Atokan.

Isopach and lithofacies map, Des Moinesian.

Isopach and lithofacies map, Missourian.

Isopach and lithofacies map, Virgilian.

Early Pennsylvanian framework; upper Morrowan and lower Derryan;

basin.

Isopachous map of Pennsylvanian System with generalized lithofacies.

Structural features at time of (Wolfcamp) deposition.

Des Moinesian paleogeography and sedimentary framework.

Thickness and lithofacies; rocks mostly of Morrow age.

Thickness and lithofacies; rocks mostly of Atoka age.

Thickness and lithofacies; rocks mostly of Des Moines age.

Thickness and lithofacies; rocks mostly of Missouri age.

Thickness and lithofacies; rocks mostly of Virgil age.

Thickness and lithofacies; rocks mostly of lower Wolfcamp age.

Interpretative isopach map, interval A.

Interpretative isopach map, interval B.

Interpretative isopach map, interval C.

Interpretative isopach map, interval D.

Interpretative isopach map, interval E.

Ely

Morrowan time, for no diagnostic fossils and no deposits 

considered of Morrowan age have been recognized in that 

part of Arizona.

South and southeast of the Grand Canyon area, the 

closest recorded deposits of Morrowan age are in the extreme southeastern corner of Arizona. In the thick 

Paleozoic sections of that area, occupying the northern end

of the Sonoran geosyncline, rocks of Morrowan age have 

been recognized in many places (Sabins, 1957; Tyrell, 

1957; Nations, 1963). Along the Mogollon Rim in central 

Arizona and elsewhere southeast of Grand Canyon, however, the entire sequence of Pennsylvanian strata, as represented by the Naco Group, apparently is younger than 

Morrowan. The Sonoran seas, therefore, could not have
PALEOGEOGRAPHY 

112° 110°

59

108°

EXPLANATION

* Outcrop data

• Well data

35°-

33°-

FIGURE D3.—Regional paleogeographic map for Morrowan time. Isopach interval 100 ft.
60 THE SUPAI GROUP OF GRAND CANYON 

112° 110°

EXPLANATION

Sea—Isopachs show thickness of

continental and marine sediments ** 

combined. Isopach interval 100 feet

33°-

FIGURE D4.—Regional paleogeographic map for Atokan time. Isopach interval 100 ft.
PALEOGEOGRAPHY

112° 110°

61

108°

EXPLANATION

Sea—Isopachs show thickness of

continental and marine sediments 

combined. Isopach interval 100 feet 

and 1000 feet

Outcrop data 

Well data

FIGURE D5.—Regional paleogeographic map for Des Moinesian time. Isopach interval 100 ft and 1000 ft.
62 THE SUPAI GROUP OF GRAND CANYON 

112° 110° 108°

EXPLANATION

Sea—Isopachs show thickness of

continental and marine sediments 

combined. Isopach interval 100 

and 500 feet

Outcrop data 

Well data

FIGURE D6.—Regional paleogeographic map for Missourian time. Isopach interval 100 ft and 500 ft.
PALEOGEOGRAPHY

112° 110°

63

EXPLANATION

Sea—Isopachs show thickness of

continental and marine sediments

combined. Isopach interval 100 feet 

and 1000 feet

Outcrop data 

Well data

33° h

FIGURE D7.—Regional paleogeographic map for Virgilian time. Isopach interval 100 ft and 1000 ft.
64

114°

THE SUPAI GROUP OF GRAND CANYON 

112° 110° 108°

37'

35C

33C

\

EXPLANATION

Land

Sea—Isopachs show thickness of

continental and marine sediments 

combined. Isopach interval 100 feet, 

500 feet

No data

* Outcrop data

• Well data

FIGURE D8.—Regional paleogeographic map for Wolfcampian time. Isopach interval 100 ft and 500 ft.

connected across central Arizona with the Watahomigi roughly parallel the western margin of the Colorado Plaembayment at that time. teau and are normal to the trend of Grand Canyon. The

The thickest sections of strata (250 and 300 ft) in the zero isopach or inner margin of the Watahomigi embayWatahomigi (Morrowan) marine embayment of the Grand ment is not far east of Grand Canyon's eastern end.

Canyon region, as delineated by isopachs (fig. D9), Deposits within the Morrowan embayment furnish no
PALEOGEOGRAPHY 65

TABLE D3.— fauna/ assemblages from Pennsylvanian well samples in 

Four Corners area showing distribution and age assignments by John 

Chronic

[Figures in columns refer to number of collections]

Morrowan

Northeastern Arizona. . . J 1 

New Mexico, San Juan

Utah, southern San 

Juan County (T. 39 S.- 

T. 43 S.) ........... 0

Utah, middle San Juan 

County (T. 32 S.-T. 

38 S.) ............. 0

Utah, northern San 

Juan County (T. 27 S.- 

T. 31 S.) ........... 0

Atokan

2

5

2

1

4

Des Moinesian Missourian

5 0 

9 0

19 M

9 1

10 3

Virgilian

0

1

5

6

1Age assignment uncertain.

mostly of carbonate rock and argillaceous mudstone. 

Compared with the overlying formations of the Supai 

Group, sandstone is conspicuously scarce and crossstratification is rare.

The megafauna of this embayment is restricted largely 

to the western and central parts. Nearly all of the large 

diagnostic brachiopods are in the area delineated by the 

250-ft isopach, where carbonate rocks are relatively thick 

bedded and form a major part of the formation. Several 

other faunal assemblages range eastward nearly as far as 

the limit of the 200-ft isopach line. Apparently all marine 

animals entered the embayment from the Cordilleran sea 

to the west.

Paleogeography of 

Manakacha Formation

evidence that surrounding landmasses were elevated. Ex- The Manakacha Formation, composed mostly or encept for a thin basal conglomerate, locally developed, and tirely of strata of Atokan age, represents a time of domiscattered lenses of consolidated gravel at a few higher nantly marine deposition in the Grand Canyon area. These

horizons, the sediments are very fine grained and consist rocks were shown as strata of Des Moinesian age on

114° 113° 112°

36°

FIGURE D9.—Isopach map of Watahomigi Formation (Morrowan and Atokan), Grand Canyon region, Arizona. Dots are locations of measured 

sections (fig. A1). Number next to dot is thickness, in feet, of formation in that section. Isopach interval 50 ft. Isopach dashed in area of poor 

control.
66 THE SUPAI GROUP OF GRAND CANYON

paleotectonic maps prepared some years ago but only recently published (McKee and Crosby, and others, 1975), 

because at that time fossils diagnostic of Atokan time had 

not been discovered in the rocks. Correlation with areas 

farther west has proved to be faulty.

An isopach map prepared from thicknesses of the Manakacha recorded in the Grand Canyon area is shown in 

figure D10. A general thickening from north to south occurs in a belt roughly parallel to the course of the Colorado 

River in Grand Canyon. The thinnest or landward margin 

of the deposit extends in a north-south direction at the 

western end of the Grand Canyon area and trends northsouth near the eastern end of the area. Midway between is 

an embayment that extends 30-60 mi northward. Isopach 

trends (fig. DlO) indicate that a land area existed to the 

north in southern Utah during Atokan time, probably the 

physiographic feature referred to as the Piute positive element (McKee and Crosby, and others, 1975, fig. 15). This 

element apparently was not high at the time because detrital sediment in the Manakacha south of the land area consists largely of uniformly fine grained sand with much silt 

(table K7). Cross-bedding directional vectors indicate

a consistent southerly direction of sediment transport 

(fig. M2) away from the shore.

Westward from the Piute landmass was the Cordilleran 

miogeosyncline (Bird Spring-Ely basin) where thick deposits, largely of carbonate sediment, accumulated during 

Atokan time (fig. D4). To the southeast in the Grand Canyon area (figs. D4, DlO) a southward thickening indicated 

by isopachs strongly suggests that the seaway may once 

have connected with the Sonoran geosyncline in southeastern Arizona, but such connection cannot be proved 

at present because the record of Pennsylvanian rocks 

has been removed by late erosion across much of central 

Arizona.

Paleogeography of 

Wescogame Formation

The Wescogame Formation of probable Virgilian age 

was formed at a time when the seas were exceptionally 

widespread in Arizona. It developed at the convergence of 

three principal transgressive seaways (fig. D7). The seas 

entered from the Bird Spring-Ely basin, to the west or

112°

36°

FIGURE D10.—Isopach map of Manakacha Formation (Atokan and Des Moinesian? age), Grand Canyon region, Arizona. Dots are locations of 

measured sections (fig. A1). Number next to dot is thickness, in feet, of formation in that section. Isopach interval 50 ft.
PALEOGEOGRAPHY 67

northwest, at the south end of the Cordilleran geosyncline; 

from the greatly expanded Paradox basin of Colorado and 

Utah to the northeast; and from the northern end of the 

Sonoran geosyncline, to the southeast.

Isopachs portraying thickness trends in the Wescogame 

Formation of the Grand Canyon region (fig. Dll) show a 

southeastward thickening. This trend, together with the 

occurrence of Virgilian-type fusulinids both in western 

Grand Canyon and along the Mogollon Rim of central 

Arizona (table E4), indicate that the Sonoran sea almost 

certainly connected from the south with the Wescogame 

embayment at that time; similar isopach and faunal 

evidence to the west suggests a connection between the 

Wescogame and Cordilleran seas. To the northeast, isopach trends provide less convincing evidence of a connection (fig. Dll), but a connecting strait may have existed 

also in this area, for Virgilian-type Triticites are recorded 

from subsurface in the Four Corners area (table D3), and 

the nearest Upper Pennsylvanian rocks of the Paradox 

basin extension are in close proximity to the Wescogame 

(fig. D7).

As in earlier parts of Pennsylvanian time the principal

positive elements controlling the distribution of life and the 

accumulation of sediments were the Defiance element, east 

of the Grand Canyon area, the Piute to the north in southern Utah, and probably an area to the southwest, as indicated by trends of thickening in isopachs (fig. D7). Because 

most of the Paleozoic record in southwestern Arizona has 

been destroyed by late erosion, however, the features in 

that direction are very poorly known.

Paleogeography of 

Esplanade Sandstone

114° 113°

The Esplanade Sandstone and its carbonate equivalent, 

the Pakoon Limestone (McNair, 1951), in the western 

Grand Canyon are of Early Permian (Wolfcampian) age. 

Because of the intertonguing relationship between these 

two formations, they are combined on the isopach map 

(fig. D12). To the west beyond the Grand Canyon area, 

their exact equivalents are not known and, as a result, their 

correlatives in adjoining areas and their relations to surrounding paleogeographic features are difficult to establish. Deposition began on a widespread erosion surface on

112°

37C

36°

FIGURE D11.—Isopach map of Wescogame Formation (Virgilian age), Grand Canyon region, Arizona. Dots are locations of measured sections 

(fig. A1). Number next to dot is thickness, in feet, of formation in that section. Isopach interval 50 ft. Isopach dashed in area of poor control.
THE SUPAI GROUP OF GRAND CANYON

strata of late Pennsylvanian age; it was followed by 

another interval of erosion, which preceded deposition of 

the Hermit Shale. The hiatus marked by this second unconformity probably was not great and the Hermit is believed (White, 1929, p. 39) to be "near the top of the Lower 

Permian". Neither the Hermit nor the Esplanade is recognized lithologically in areas to the northeast or southeast of 

Grand Canyon, so these units either change facies or are 

absent in those directions.

Some concept of the regional setting in which the Esplanade formed can be gained by reference to an isopach map 

of the combined formations of Wolfcampian age, prepared 

for Arizona and surrounding areas (fig. D8). As during 

deposition of the older formations in the Supai Group, the 

Defiance and Zuni positive elements formed a strongly 

stable area in northeastern Arizona and adjacent New 

Mexico.

North of this positive element was the Paradox basin of 

Utah and Colorado, including numerous small sinking 

basins that accumulated much sediment. A second but less 

well-defined positive element was west of the Paradox

basin. The persistent Sonoran geosyncline in southeastern 

Arizona and the southern part of the Cordilleran geosyncline in southern Nevada, adjacent to northwestern Arizona, were major negative areas during Wolfcampian time.

An isopach map of the Esplanade Sandstone including 

tongues of the Pakoon Limestone in the western Grand 

Canyon area shows trends in thickening (fig. D12) almost 

opposite to those of .the two underlying formations of the 

Supai Group (figs. DlO, Dll). In general, thickening is 

from south to north in the Esplanade, except in the extreme 

western part of the area where it is from east to west. 

In contrast, the Manakacha and Wescogame Formations 

have directions of thickening from north to south.

On the basis of isopach trends and the location of positive and negative elements shown on the regional map of 

Wolfcampian deposits (fig. D8), the probability that seas 

in the Grand Canyon area transgressed from both northwest and northeast seems likely. On the other hand, waters 

of the Sonoran geosyncline may not have extended into 

northern Arizona at that time. A likely source of the extensive clean sand deposits in the Esplanade was to the

36'

FIGURE D12.—Isopach map of Esplanade Sandstone (Wolfcampian age) including tongues of Pakoon Limestone (McNair, 1951) to the west; Grand 

Canyon region, Arizona. Dots are locations of measured sections (fig. A1). Number next to dot is thickness, in feet, of formation in that section. 

Isopach interval 100ft. Isopach dashed in area of poor control.
PALEOGEOGRAPHY 69

north in a positive area in the central or western part of 

southern Utah, as indicated by cross-bedding dip-directions in the sand (figs. M2, D5).

The Pakoon Limestone that interfingers with the lower 

part of the Esplanade and marks an abrupt change from 

quartz sand to calcium carbonate near the western end of 

Grand Canyon seems to indicate an area of barrier buildup 

and contains an abundance of coral mounds. Along this 

belt, isopachs are close together, indicating an abrupt increase in rate of deposition seaward, and perhaps a hinge 

or the margin of an area of more rapid subsidence to the 

west. East of the barrier and within the Esplanade, extensive beds of gypsum perhaps indicate areas of concentrated 

sea water, cut off from the western sea.

CORRELATION WITH STRATA 

OF ADJOINING AREAS

Correlation with strata 

of central Arizona

Correlation of formations in the Supai Group of Grand 

Canyon with the nearest Pennsylvanian-Permian strata to 

the south, at Oak Creek and Sycamore Creek (fig. D13), 

can be made only on the basis of lithologic similarities, for 

as yet no diagnostic fossils have been found at those localities. The nearest recorded fossil-bearing sites in a southerly 

direction (fig. D13) are along the Mogollon Rim at Fossil 

Creek (Jackson, 1952; Brew, 1965), and East Verde River, 

Tonto Creek, and Kohls Ranch (Brew, 1965). Farther 

south and east from the Mogollon Rim at Big Spring Canyon, Carrizo Creek, and Black River (Brew, 1965) fossils 

are progressively more numerous and varied and represent 

a greater time range.

The lower part of the Watahomigi Formation in 

Grand Canyon contains brachiopods of Early Pennsylvanian (early Morrowan) age and, about midway in the 

formation, Linoproductus nodosus of late Morrowan age 

occurs. None of these fossils (discussed under "Age of the 

Supai Group," chapter E) occurs in sections along the 

Mogollon Rim, and apparently no strata of Morrowan age 

are present there. In contrast, rocks dated as Morrowan 

are reported from southeastern Arizona (Gilluly and 

others, 1954; Sabins, 1957; Tyrell, 1957; Nations, 1961, 

1963). Thus, in Early Pennsylvanian time the shelf seas of 

the Grand Canyon area had no direct connection with 

waters of the Sonoran geosyncline to the southeast.

The uppermost part of the Watahomigi and most, if not 

all, of the overlying Manakacha Formation contain 

fusulinids considered to be of Atokan age as described 

under "Age of the Supai Group" (chapter E). Of these fossils, Fusulinella sp. and Pseudostaffella sp. that are associated at several localities in eastern Grand Canyon and 

Eoschubertella sp. that has been found at many sites

FIGURE D13.—Stratigraphic sections including fossil localities (solid circles) referred to in Mogollon Rim area, south and southeast of 

Grand Canyon, Ariz. (Modified from Jackson, 1952, and from Brew, 1965). 1, Fossil Creek; 2, East Verde River; 3, Tonto Creek; 4, Kohls 

Ranch; 5, Big Spring Canyon; 6, Carrizo Creek; and 7, Black River.
70 THE SUPAI GROUP OF GRAND CANYON

in western Grand Canyon are not reported from the 

Mogollon Rim area south of Grand Canyon.

The lowest fusulinid zones reported from sections along 

the Mogollon Rim contain Fusulina sp. and Wedekindellina 

sp., both indicators of Des Moinesian age (Brew, 1965, 

p. 69, table 4). This evidence supports the concept (Brew, 

1965, fig. 10) that transgressive seas from the Sonoran geosyncline had not advanced far north by the end of Atokan 

time (table E4).

Because neither Fusulina sp. nor Wedekindellina sp. has 

yet been found in the Grand Canyon sections 50-60 mi 

north of the Mogollon Rim in central Arizona, correlation 

at this time level cannot be established. A strong probability exists, therefore, that the Des Moinesian age is not represented in Grand Canyon rocks.

Rocks of Missourian age are recognized in the east-central Arizona area on the basis of four species of Triticites 

and one chonetid (Brew, 1965, table 4). None of these species occur as far north as the Mogollon Rim sections, but 

the fauna is recorded by Brew (1965, p. 62) from Carrizo 

Creek and Big Spring Canyon sections (fig. D13) 40-80 mi 

farther south and east. No fossils identified as of Missourian age have yet been recognized in the Supai of Grand 

Canyon and probably the time interval is represented 

within the hiatus at the base of the Wescogame Formation.

The Wescogame Formation of the Supai Group probably can be correlated with upper parts of the Naco Formation in east-central Arizona. Several species of Triticites 

and one of Dunbarinella are used by Brew (1965, table 4) 

in zonation of the Naco Formation in sections from Black 

River to Big Spring Canyon (fig. D13).

North from Black River, Virgilian Triticites are recorded 

by Lokke (1962, p. 84, 85) in the subsurface Naco Formation of Navajo County (Lockhart No. 1 Aztec Land and 

Cattle Co. well) and of Apache County (Pan American IB 

New Mexico and Arizona Land Co. well). However, thinning of Pennsylvanian strata northward from these localities and progressive elimination of many fusulinid-bearing 

beds in that direction (Lokke, 1962, p. 85) suggest that the 

southern seaway did not connect with that of the Paradox 

basin across eastern Arizona during Virgilian time.

In western Grand Canyon at Hidden Canyon, species of 

Virgilian-type Triticites, as recognized by R. C. Douglass 

(written communs., 1966, 1973), indicate a Virgilian age 

for the Wescogame Formation. Although in both eastern 

Arizona and central Arizona fossil-bearing strata of Virgilian age have also been reported, a direct marine connection at that time between these areas and the western 

Grand Canyon region is questionable. In the intermediate 

area of eastern Grand Canyon no marine fossils have been 

found in the Wescogame. Isopach trends suggest connections from the south and the west to the western part of 

the canyon area (fig. Dll).

The Pakoon Limestone in extreme western Grand Canyon, believed on the basis of intertonguing relationships to 

be a lateral equivalent of the Esplanade, contains abundant 

fusulinids. Among these are the characteristic Wolfcampian genera of Schwagerina, Pseudoschwagerina, 

Schubertella, Triticites, and others. This assemblage apparently does not occur in the upper Paleozoic strata of the 

Mogollon Rim south of Grand Canyon. In that area no 

Wolfcampian fusulinids have been recorded.

Farther southeast, at Carrizo Creek, Big Spring Canyon, 

and elsewhere, some species of Dunbarinella and Triticites, 

the age of which is doubtful, are assigned a "post-Virgil" 

age (Brew, 1965, p. 63). Absence of diagnostic Wolfcampian fusulinids in the central Arizona area makes correlation 

with the Pakoon-Esplanade strata impossible. Wolfcampian time apparently is represented in the Mogollon Rim 

sections by barren red beds commonly referred to as the 

Supai formation.

Correlation with strata to west 

and northwest of Grand Canyon

Most Pennsylvanian-Permian sections in parts of 

Nevada and Utah that are adjacent to the Grand Canyon 

area contain an abundance of fossils that have been the 

subject of three principal investigations (Steele, 1959; 

Welsh, 1959; Brill, 1963). As a result, the various taxa can 

be directly compared with fossils in the Supai Group and 

tentative correlations between the Grand Canyon formations and their lateral equivalents to the west and northwest can be established. A summary of recorded sites compiled by Douglass (1974, p. 846) is given in table D4 and 

figure D14.

The lower two-thirds of the Watahomigi Formation, 

considered to be of Morrowan age chiefly on the basis of 

several diagnostic brachiopods, represents the oldest Pennsylvanian strata in the Grand Canyon area. In the Nevada 

and Utah sections, rocks of Morrowan age likewise are recorded, but the diagnostic brachiopods recognized in the 

Watahomigi, including the very common Anthrocospirifer 

occiduus and the marker form, Linoproductus nodosus, 

are not listed either by Welsh (1959, tables 1, 2) or by Brill 

(1963, p. 313). On the other hand, Rhipidomella nevadensis, Hustedia miseri, and a few other species that are cited 

by both geologists as indicators of the earliest Morrowan 

zone in Nevada have not been found in Grand Canyon sections, possibly because deposition did not begin in the 

Grand Canyon area until later in Morrowan time.

Some taxa that are recorded in the "Lowermost Pennsylvanian: Lower Morrow" in the basin sections of Nevada 

(Welsh, 1959, table 1), but also occur in the lower part of 

the Watahomigi, are the coral Michelinia sp. (fig. E5), the 

brachiopods Derbyia sp., Orbiculoidea sp., Punctospirifer 

sp., Buxtonia sp., Schizophoria sp. (fig. El), and the 

foraminifer Millerella sp.
PALEOGEOGRAPHY 71

TABLE D4.—Comparison offusulinid genera of Grand Canyon and those listed by R. C. Douglass (1974) from southern Nevada and California. Localities

shown in figure D14

Grand Canyon area 

(Recorded in this paper)

Southern Nevada Calif. 

(Recorded by Douglass, 1974)

Formation

Pakoon Limestone1

Wescogame Formation 

Manakacha Formation .

Watahomiei Formation

Genus

Pseudoschwagerina .

Staffella .......... 

Pseudostaffella . . . . .

Millprplla

Eastern Twin 

Grand Parashant Springs Snap Pigeon 

Canyon Canyon Canyon Canyon Wash

X

X X

y

- X X X X

y

y

y

X - - - X

Hidden 

Canyon

X 

X

X 

X 

X

X 

X

X

Iceberg 

Canyon

X

X 

X 

X

X

...

Arrow 

Canyon

X

X 

X

X 

X

X 

X

Y

Lee 

Canyon

X

X 

X 

X

X

X 

X 

X

Y

Mountain 

Springs 

Summit

X 

X 

X 

X 

X

Y

Southeast 

of 

Baker

X 

X 

X 

X 

X

(lower part).

*Ot McNair (1951);

38°

36°

Esplanade Sandstone-equivalent in western Grand Canyon.

118° 116° 114° 112° 110° \N

I

" \

\\

\ \

\

0 50

I I

\ •! 

\ ^

\ O Las Vegas ,

\3 r'

\ \

100 MILES \ I

O Baker \ \ 

• 4 V

I /

I

__

/ 

»5 ,~^ >

:; i°/x^u_,

i

UTAH

Y ARIZONA

\

FIGURE D14.—Fusulinid localities cited in table D4, discussed by Douglass (1974) (loc. 1-4), and recorded in Grand Canyon 

(this paper) (loc. 5-10). 1, Arrow Canyon; 2, Lee Canyon; 3, Mountain Springs Summit; 4, Southeast of Baker, Calif.; 

5, Hidden Canyon; 6, Pigeon Wash; 7, Snap Canyon; 8, Iceberg Canyon; 9, Twin Springs Canyon; and 10, Parashant 

Canyon.

Strata of Virgilian age, recognized by distinctive types of 

Triticites at Hidden Canyon in western Grand Canyon 

(fig. E13), are also found at Pakoon Ridge, Arizona, and 

Frenchman Mountain, Nevada, according to Welsh (1959, 

p. A-12, A-61). Seas of this age are believed to have occupied much of the southern Nevada and northwestern Arizona region (Brill, 1963, p. 316), but the diagnostic forms 

of Triticites have not been recorded from sections other 

than those previously noted.

A locally common fusulinid fauna of Wolfcampian age 

including such characteristic genera as Schwagerina, 

Pseudoschwagerina, and Triticites (fig. E15) occurs in the
72 THE SUPAI GROUP OF GRAND CANYON

Pakoon Limestone at various places in the western part of 

Grand Canyon. Westward from there, Schwagerina is recorded at Frenchman Mountain, Bird Spring Range, Mormon Mountains, and elsewhere in southern Nevada 

(Welsh, 1959, p. A-33, A-61, A-74) and in southern California (table D4, fig. D14).

The fusulinid genera Fusulina and Wedekindellina that 

are believed restricted to and characteristic of Des Moinesian time have not been recorded from the Grand Canyon 

area, although they occur in many ranges not far to the 

west. Wedekindellina is reported from Frenchman Mountain and the Virgin Mountains of Nevada (Welsh, 1959, 

p. A-61, A-21) and from Pakoon Ridge, Arizona (Welsh, 

1959, p. A-12), and Fusulina is listed from the last two of 

these localities. Thus, the absence of these genera in the 

Grand Canyon sections suggests that rocks of Des Moinesian age are either lacking in the Supai or limited to the uppermost part of the Manakacha Formation, the age of 

which is poorly established.

No fossils of Missourian age have as yet been recognized 

in the sections of Grand Canyon. Their occurrence there 

seems unlikely because fusulinids of Virgilian-type of the 

genera Ozawainella and Triticites are recorded from not 

far above the widespread erosion surface and conglomerate at the base of the Wescogame Formation (fig. E13). 

Furthermore, no faunas of Missourian age are recognized 

by either Welsh (1959) or Brill (1963) in adjoining sections 

to the west and northwest. Missourian seas of the Great 

Basin area were restricted to the Pioche and Oquirrh 

Basins to the west according to Brill (1963, p. 315). The 

section that is nearest to Grand Canyon on the west, 

reported to have Missourian fossils, is at Frenchman 

Mountain, Nevada. In this range Triticites aff. T. 

plicatulus has been recorded by Steele (1959, p. 72).

Correlation with strata of 

the Four Corners area

Throughout Pennsylvanian time a marine environment 

prevailed in the Paradox basin of eastern Utah and western 

Colorado. Seas periodically were greatly restricted, but 

at other times they expanded and their waters extended 

southward past the Four Corners into Arizona and New 

Mexico (McKee and Crosby, and others, 1975).

Correlation between formations of the Supai Group 

of the Grand Canyon area and rocks of PennsylvanianPermian age in the Four Corners area is difficult because 

sections in the Four Corners area are known mainly from 

subsurface data and reliable dating is restricted mostly to 

sparse fusulinid records. On this basis, however, certain 

times have been determined when faunas of the two areas 

probably had easy intercommunication as shown by distinctive fossil forms common to both. A chart showing distribution of faunal assemblages in Pennsylvanian well 

samples from the Four Corners area has been prepared 

(table D3).

Strata of Morrowan age probably did not extend south 

of the Utah-Arizona state line from the Paradox basin 

area, as shown in table D3. Beds of Atokan age in the Four 

Corners area, recognized by species of Fusulinella (John 

Chronic, oral commun., 1974), may correlate with the upper part of the Watahomigi or the Manakacha Formation 

or both, of the Grand Canyon area, where Atokan forms 

of this genus occur in both formations. Strata of Des 

Moinesian age containing Wedekindellina and Fusulina are 

represented in many collections from Four Corners localities, but these genera are unrecorded from Grand Canyon 

strata. Nevertheless, rocks of Des Moinesian age may possibly be represented in Grand Canyon by the barren uppermost part of the Manakacha. Strata of Missourian age apparently were restricted to the area north of Arizona, but 

rocks of Virgilian age containing distinctive species of 

Triticites occur both in Four Corners and in Grand Canyon 

areas and permit correlation of the Wescogame Formation 

with strata of similar age at Four Corners.

REFERENCES CITED

Baars, D. L., 1962, Permian System of Colorado Plateau: American 

Association of Petroleum Geologists Bulletin, v. 46, no. 2, p. 149-218.

Bissell, H. ]., 1960, Eastern Great Basin Permo-Pennsylvanian strata— 

Preliminary statement: American Association of Petroleum Geologists Bulletin, v. 44, no. 8, p. 1424-1435.

Brew, D. C., 1965, Stratigraphy of the Naco Formation (Pennsylvanian) 

in central Arizona: Cornell University, Ph. D. thesis, 201 p.

Brill, K. G., Jr., 1963, Permo-Pennsylvanian stratigraphy of western 

Colorado Plateau and eastern Great Basin regions: Geological Society of America Bulletin, v. 74, no. 3, p. 307-330.

Brown, S. C., and Lauth, R. E., 1958, Oil and gas potentialities of northern Arizona, in Guidebook of the Black Mesa basin, northeastern 

Arizona: New Mexico Geological Society 9th Field Conference 

Guidebook, p. 153-160.

Coogan, A. H., 1964, Early Pennsylvanian history of Ely basin, Nevada: 

American Association of Petroleum Geologists Bulletin, v. 48, no. 4, 

p. 487-495.

Darton, N. H., 1925, A resume of Arizona geology: Arizona Bureau of 

Mines Bulletin 119, 298 p.

Douglass, R. C., 1974, Fusulinids in the Basin and Range Province in 

California, Nevada, and Utah: Journal of Paleontology, v. 48, no. 4, 

p. 846-853.

Eardley, A. J., 1949, Paleotectonic and paleogeologic maps of central 

and western North America: American Association of Petroleum 

Geologists Bulletin, v. 33, no. 5, p. 655-682.

____1951, Structural geology of North America, 1st edition: New 

York, Harper and Brothers, 624 p. 

_1962, Structural geology of North America, 2d edition: New York,

Harper and Row, 738 p. 

Elston, Wolfgang E., 1960, Structural development and Paleozoic stratigraphy of Black Mesa basin, northeastern Arizona, and surrounding areas: American Association of Petroleum Geologists Bulliten, 

v. 44, no. 1, p. 21-36.
PALEOGEOGRAPHY 73

Gilluly, }., Cooper, J. R., and Williams, J. S., 1954, Late Paleozoic stratigraphy of central Cochise County, Arizona: U.S. Geological Survey Professional Paper 266, 49 p.

Gregory, H. E., 1917, Geology of the Navajo Country—A reconaissance 

of parts of Arizona, New Mexico, and Utah: U.S. Geological Survey 

Professional Paper 93, 161 p.

Havener, K. C., 1958, Pennsylvanian framework of sedimentation in 

Arizona: Arizona University, M.S. thesis, 73 p.

Havener, K. C., and Pye, W. D., 1958, Pennsylvanian paleogeography 

of Arizona, in Guidebook of the Black Mesa basin, northeastern 

Arizona: New Mexico Geological Society 9th Field Conference 

Guidebook, p. 78-81.

Heylmun, E. B., 1958, Paleozoic stratigraphy and oil possibilities of 

the Kaiparowits region, Utah: American Association of Petroleum 

Geologists Bulletin, v. 42, no. 8, p. 1781-1811.

Hite, R. J., and Cater, F. W., 1972, Pennsylvanian rocks and salt anticlines, Paradox basin, Utah and Colorado, in Geologic atlas of the 

Rocky Mountain region: Denver, Rocky Mountain Association of 

Geologists, p. 133-137.

Huddle, J. W., and Dobrovolny, E., 1945, Late Paleozoic stratigraphy 

and oil and gas possibilities of central and northeastern Arizona: 

U.S. Geological Survey Oil and Gas Investigations Preliminary 

Chart No. 10.

Irwin, C. D., 1971, Stratigraphic analysis of upper Permian and lower 

Triassic strata in southern Utah: American Association of Petroleum 

Geologists Bulletin, v. 55, no. 11, p. 1976-2007.

Jackson, R. L., 1952, Pennsylvanian-Permian facies of the Supai Formation in central Arizona, in Guidebook for southern Arizona: Arizona 

Geological Society, p. 143-146.

Kottlowski, F. E., and Havener, K. C., 1962, Pennsylvanian rocks of 

the Mogollon Rim area, Arizona, in Guidebook of the Mogollon Rim 

region, east-central Arizona, New Mexico Geological Society, 13th 

field Conference, 1962: Socorro, New Mexico Bureau of Mines and 

Mineral Resources, p. 77-83.

Lessentine, R. H., 1965, Kaiparowits and Black Mesa basins—Stratigraphic synthesis: American Association of Petroleum Geologists 

Bulletin, v. 49, no. 11, p. 1997-2019.

Lokke, D. H., 1962, Paleontological reconnaissance of subsurface Pennsylvanian in southern Apache and Navajo Counties, Arizona, in 

Guidebook of the Mogollon Rim region, east-central Arizona, New 

Mexico Geological Society, 13th Field Conference, 1962: Socorro, 

New Mexico Bureau of Mines and Mineral Resources, p. 84-86.

Longwell, C. R., 1949, Structure of the northern Muddy Mountains area, 

Nevada: Geological Society of American Bulletin, v. 6, no. 5, 

p. 923-968.

McKee, E. D., 1951, Sedimentary basins of Arizona and adjoining areas: 

Geological Society of America Bulletin, v. 62, no. 5, p. 481-506.

____1969, Stratified rocks of the Grand Canyon, in The Colorado 

River region and John Wesley Powell: U.S. Geological Survey Professional Paper 669-B, p. 23-58.

McKee, E. D., and Crosby, E. J., and others, 1975, Paleotectonic investigations of the Pennsylvanian System in the United States; Part I, 

Introduction and regional analyses of the Pennsylvanian System: 

U.S. Geological Survey Professional Paper 853, 349 p. [1976].

McKee, E. D., and Oriel, S. S., and others, 1967, Paleotectonic investigations of the Permian System in the United States: U.S. Geological 

Survey Professional Paper 515, 271 p.

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Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

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Regional synthesis of the Pennsylvanian System, in Geologic atlas of 

the Rocky Mountain region: Denver, Rocky Mountain Association 

of Geologists, p. 111-127.

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northeast Nevada [abs.]: Geological Society of America Bulletin, 

v. 68, no. 12, pt. 2, p. 1854-1855.

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52 p.

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of southeastern Arizona: Journal of Paleontology, v. 37, no. 6, 

p. 1252-1264.

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atlas of the Rocky Mountain region: Denver, Rocky Mountain

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of America Bulletin, v. 53, no. 9, p. 1255-1282.

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64 p.

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Carnegie Institution of Washington Publication 405, 221 p.

THE SUPAI GROUP OF GRAND CANYON

DISTRIBUTION AND AGE 

OF FAUNA AND FLORA

Chapter E 

By EDWIN D. McKEE

Contents

Page

Marine fauna of the Supai Croup ...... .......................... .......................... 77

Marine fauna of the Watahomigi Formation ... .............................................. 77

Marine fauna of the Manakacha Formation .... .......... .................................. 85

Marine fauna of the Wescogame Formation ..... .... ..................................... 85

Marine fauna of the Pakoon Limestone . . ............ .............. ....................... 87

Tracks of vertebrate animals of the Wescogame Formation ...... .... ........................ 91

Tracks of vertebrate animals of the Esplanade Sandstone ...................... 93

Absence of vertebrate skeletal remains ..... ........................ ..... .... 96

Flora of the Supai Croup .................. ............................. .... ... 97

Bioclastic debris of the Watahomigi Formation ........ ............................. 100

Bioclastic debris of the Manakacha Formation ................................................. 102

Bioclastic debris of the Wescogame Formation ................................................. 103

Bioclastic debris of the Esplanade Sandstone and Pakoon Limestone , .............................. 104

Age of the Supai Croup . .... .. .............................................. 105

Age of the Watahomigi Formation . ..... ............. . ... .................. 105

Age of the Manakacha Formation .......................................................... 107

Age of the Wescogame Formation . ................................................ 109

Age of the Pakoon Limestone ... ..................................................... 111

Age of the Esplanade Sandstone ........... . . . ..... ................ 111

References cited ......................................................................... 111

75
76 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURES E1-E8. Diagrams showing distribution of:

E1. Brachiopods of the Watahomigi Formation .......................... 79

E2. Gastropods of the Watahomigi Formation .......................... 80

E3. Pelecypods of the Watahomigi Formation ................. 81

E4. Trilobites and corals of the Watahomigi Formation .................... 82

E5. Conulariids and nautiloids of the Watahomigi Formation ............... 83

E6. Bryozoans of the Watahomigi Formation . ................ 83

E7. Sharks teeth of the Watahomigi Formation . ........ 84

E8. Principal invertebrate megafossi Is of the Manakacha Formation . ... . 86

E9. Photographs of Bellerophon (Bellerophon) n. sp. from the Manakacha Formation . 87 

E10. Map showing distribution of fusulinids of Atokan age in upper part of Watahomigi

Formation and Manakacha Formation ................. . . . . 87

E11. Diagram showing horizons of fusulinids of Atokan age in Grand Canyon sections .... 88

E12. Map showing distribution of Endothyra media and E. teres in upper part of the

Manakacha Formation and lower part of the Wescogame Formation .... ... 89

E13. Diagram showing distribution of principal marine fossils of the Wescogame

Formation .... .. .... ... .................................... 90

E14. Photographs of pelecypods from the Wescogame Formation .............. 91

E15. Map showing measured sections from which clasts of marine fossils have been

obtained in the Wescogame Formation ..... ... 92

E16. Map showing measured sections from which clasts of marine fossils have been

obtained in the Esplanade Sandstone and Pakoon Limestone ... . . 93

El 7. Diagram showing distribution of corals, bryozoans, gastropods, and sharks teeth

of Pakoon Limestone ................. .... ... ..... .... .... 94

E18. Diagram showing distribution of fusulinids of the Pakoon Limestone and Esplanade Sandstone ............. . ..... ... .... ......... 95

E19. Map showing geographic distribution of Jriticites and Schubertella in Esplanade

Sandstone and Pakoon Limestone ...................... 96

E20. Diagram showing distribution of brachiopods of the Pakoon Limestone ......... 97

E21-E23. Photographs of:

E21. Trackways of vertebrate animals in the Wescogame Formation and

modern amphibian footprints in wet sand ............... 98

E22. Trackways of vertebrate animals in the Wescogame Formation ........ 99

E23. Trackways of vertebrate animals in Esplanade Sandstone ....... 100

E24. Map showing localities of continental flora in the Manakacha Formation ........... 100

E25-E30. Maps showing distribution of:

E25. Bioclastic debris containing pelmatozoans, Watahomigi Formation ....... 102

E26. Bioclastic debris containing foraminifers, Watahomigi Formation ......... 103

E27. Bioclastic debris containing bryozoans, Watahomigi Formation ....... 104

E28. Bivalves in bioclastic limestone, Watahomigi Formation . 105 

E29. Various marine fossils in bioclastic debris of the Manakacha Formation . . 106 

E30. Bivalve fragments in bioclastic limestones of the Manakacha

Formation .... .... ..... ............................. 107

E31. Maps showing relative abundance of various marine fossils in bioclastic debris,

Wescogame Formation ... ............ ..... ............ 108

E32. Maps showing relative abundance of various marine fossils in bioclastic debris,

Esplanade Sandstone and Pakoon Limestone ......... ..................... 109

Tables

Page

TABLE E1. Foraminifers and associated microorganisms of the Supai Group ................. 78

E2. Conodonts of the Watahomigi Formation (below Atokan conglomerate) at Separation Canyon ... ... .. ............ .............. ....... 84

E3. Land plants, animals, and minor structures in formations of the Supai Group . 101 

E4. Fusulinids of the Supai Group and Pakoon Limestone in Grand Canyon area compared with those reported from areas to the northwest and southeast ............ 110
DISTRIBUTION AND AGE OF FAUNA AND FLORA 77

MARINE FAUNA OF THE 

SUPAI GROUP

Each of the four formations comprising the Supai Group 

in Grand Canyon locally contains a faunal assemblage represented by numerous individuals, but relatively few 

genera and (or) species. Of the 11 animal groups included, 

the brachiopods have the greatest variety with a total of 27 

genera and (or) species. Next in order of abundance 

(number of genera and (or) species) are pelecypods with 

23, gastropods with 20, and corals with 11. Among the 

megafossils the brachiopods are the most common from 

the standpoint of individuals and are most widespread.

The distribution and concentration of individuals within 

each formation clearly seem to have been controlled by 

environmental factors that reflect geographic position and 

age. Seventeen of the 18 genera of brachiopods, for instance, are found in the Watahomigi Formation, whereas 

only 2 are in the Manakacha and 4 in the Esplanade (fig. 

El). Also, most of the gastropods (18) and pelecypods (21) 

are in the Watahomigi, and trilobites are most widespread 

in it (10 localities) (figs. E4, E8). This formation consists 

largely of argillaceous mud and carbonate sediment and, 

unlike the younger formations, includes little sand. In contrast, the Lower Permian Pakoon Limestone (McNair, 

1951), which intertongues with the Esplanade in western 

Grand Canyon, consists almost entirely of limestone and 

dolostone and contains most of the fusulinids (7 genera) 

and corals (9 genera) (figs. E13, E15).

Types of marine animals, other than those indicated 

above, that occur in one or more divisions of the Supai 

Group are as follows: Bryozoans are in general uncommon, but are represented by seven genera in the Watahomigi (fig. E6), and only locally by one or two in younger 

formations (figs. E8, E17). Crinoids and echinoids occur as 

bioclastic detritus—in many places large and only slightly 

worn fragments, elsewhere much comminuted—in all formations of the Supai. Conodonts are recorded from the 

Separation Canyon area in western Grand Canyon where 

four genera have been recognized in the Watahomigi 

Formation. They have not been noted elsewhere. Conulariids were found at two localities (fig. E5) in the 

Watahomigi.

A review of the microorganisms, exclusive of fusulinids, 

made by Bernard Mamet in 1972 (table El) shows a total of 

38 taxa. Included in this list are four types of algae and two 

or more foraminiferal species included in several genera. 

These organisms are concentrated largely, but not exclusively, in areas with a high proportion of carbonate strata, 

in western Grand Canyon; they occur in all the formations 

of the Supai Group, although only a few were collected 

from the Pakoon Limestone.

An obvious problem in interpreting the microfauna of 

the Supai, including the foraminifers, is that many of the

animals are in sediments that represent high-energy conditions and, in at least some specimens, considerable transportation and erosion are represented. Thus, conclusions 

concerning the environment of life and the age of the enclosing sediment may be open to question. Two convincing illustrations of the reworking of faunas have been 

noted.

First, a specimen of Fusulinella found in the Wescogame 

Formation at Whitmore Wash probably was derived from 

the Manakacha. Its age almost surely is not younger than 

Des Moinesian, yet it is preserved in rocks considered of 

Virgilian age and occurs as eroded fragments forming 

clastic grains. The second example is from Toroweap 

Valley where fusulinellids, considered by R. C. Douglass 

(written commun., 1973) to be of late Atokan or early 

Des Moinesian age, are found in strata of the Wescogame 

Formation. The specimens occur as clastic grains in sand, 

and probably were transported into Wescogame strata 

from the underlying formation.

MARINE FAUNA OF THE 

WATAHOMIGI FORMATION

The Watahomigi Formation contains a moderately varied 

and locally abundant brachiopod fauna throughout most of 

the western Grand Canyon region (fig. El). The fauna consists of 17 genera, which are distributed largely within 

three general zones: (1) at or near the base, (2) in thickbedded limestone that forms a resistant cliff at about the 

middle, and (3) in the uppermost carbonate rock ledges. A 

majority of the brachiopods belong to either of two 

groups—the productids and the spiriferids—each of which 

is represented by a number of genera and species.

The most abundant brachiopod species doubtless is a 

small form of Composita, referred to C. gibbosa, but two 

other species of Composita are also numerous (fig. El). This 

genus has been found in the formation at 15 sites, ranging 

east as far as Havasu Canyon, and is extremely common at 

many of these localities. Near the bottom of the 

Watahomigi, Composita commonly occurs in or near the 

basal conglomerate where individual ovoid shells are scattered among chert or quartz pebbles of similar size (fig. JIB, 

E). Locally, however, species of Composita form a majority 

of the particles within a conglomeratic bed. In many places 

they seem to have been rolled about and abraded and are 

not buried in life positions. Although they occur largely in 

the basal 10-12 ft of the formation, at some localities they 

are common at 40-60 ft above the base and at a few places, 

in the extreme west, they occur about 150 ft above the base 

(fig. El).

Anthrocospirifer, probably the second most common 

genus in the formation, is represented by at least four 

species and has been collected at 14 localities including
78 THE SUPAI GROUP OF GRAND CANYON

TABLE E1.—Foraminifers and associated microorganisms from the Supai Croup and the Pa/coon Limestone1 showing distribution by formations,

occurrence in microfacies, and age assignments

[Compiled from data furnished by Bernard Mamet]

Rock unit Microfacies2 Class

Mamet age 

indicators

and 

assignments3

E ° 

o ~

u c?

y, § S. £

Lacks mud; 

pelletoidal

grain 

support

Coarsegrained; 

grains 

bound

Grains

not

bound Attached 

together forams

Ammoverte//a sp .............. 0 0 1

Apterrinellids ................. 7 14 10

Archaediscidae ................ 2 0 0

Asteroachaediscus sp ........... A 2 0 0

Asphaltina sp ................. B 1 1 0

Biseriamminds ................ 0 0 0

Biseriella sp ................... A 3 2 2

Bradyina sp ................... 0 0 2

Calcisphaera sp ................ 0 8 1

Calcisphaera laevis ............. 2 0 0

Dasyclad algae ................ 1 0 0

Diplosphaerina sp .............. 0 0 0

far/and/a ..................... 1 4 0

Endothyridae ................. 4 5 1

Endothyra sp .................. 0 4 1

E. bowman/ Brown emend Brady . 022

E. media ..................... C 4 10 4

E. feres ....................... C 0 6 3

Eolasiodiscus sp ............... 1 1 0

cf. Eoschubertella sp ............ B 2 3 2

fotufaen't/na sp ................ 1 0 3

Eovolutina sp ................. 0 1 0

Globivalvulina? sp ............. A 3 3 2

C. bulloides .................. A 0 0 4

Neoarchaediscus incertus ........ A 1 0 0

N. parvus .................... A 1 0 0

Orthovertella sp ............... 1 0 0

Osag/a sp ..................... 1 0 0

Palaeonubicularia sp ........... 1 2 0

Palaeotextulariidae ............ 0 1 0

Polytaxis sp ................... 0 1 0

Priscella sp ................... 2 1 2

cf. Profusulinella? sp ............ 0 0 2

Pseudocornuspira sp ........... 1 0 1

Pseudoendothyra sp ............ 0 0 1

Spongiostramids ............... 2 0 0

Tetrataxis sp .................. 1 4 2

Tuberitina sp .................. 0 0 2

Volvotextularia sp .............. 1 0 0

Wefherede//a sp ............... 3 0 0

Algae.

X Insertae sedis.

Do. 

Algae. 

X

X 

X

Fusulinid.

Algae.

Fusulinid.

Algae.

lOfMcNair(1951); equivalent of Esplanade Sandstone in western Grand Canyon. 

2Microfacies as recognized by Bernard Mamet (written commun., Nov. 16, 1972):

1. "A basal unit composed of pelletoidal-oncolithic-botryoliticgramstone with a sieved microfauna."

2. "* * *acoarse grained oncolithic-botryolitic grainstone-boundstone (birdseye bahamitel* * *."

3. "* * 'composed mostly of silty to sandy pelletoidal fine-grained wackestones, packstones and gramstones. Calcareous silts are also abundant."

4. "* * 'identified on the abundance of mud-filled small fusulinids, while the small forams are almost exclusively attached forms." 

Indicators and probable age by Bernard Mamet (written commun., Nov. 16, 1972): 

A. Suggest Morrowan-Atokan equivalent (microfacies 1). 

B. Not younger than Middle Pennsylvanian (microfacies 2). 

C. Des Momesian equivalent or slightly younger (microfacies 3).

most of those studied in western Grand Canyon. A large 

form of this genus (fig. El), identified by Mackenzie Gordon, Jr., as A. occiduus, occurs in middle and upper limestones of the formation. It is considered by Dunbar and 

Condra (1932, p. 325) to indicate "Lower Pennsylvanian 

age." The species has been found in the Supai Group only
DISTRIBUTION AND AGE OF FAUNA AND FLORA 79

DRTH

dden L

myon Or

30) SOUTH Om

-

:

-

Co Co,At^ At Piaeon Pigeon Cgnyon Snap Twin Cg Springs Sc Qt

^-^ ^~~--.^*Wo«> (27) <25> °e

De,At 

F,Ls

Cs,At

t-\j

-

-

r\*

Ls

Co,At

-

-

/,7>

Or,Pc,Bu,Li,Lp,Aa

Ls,Lp,Cg,Aa

Se,Lp,p,Cm,At ^^

on

Li

Ls

Lp

P 

r

A 

Co,Sc,Cs Cg

Ot,Cs,At,An Co

NORTHWEST

Iceberg

Canyon

(31)

Guano 

Cave 

(26)

SOUTHEAST 

Hindu

At

(34

Pc,Co,Cr 

Li,Aa

Aa 

De,Aa Co 

Cg,At

EXPLANATION

Lingula sp.

Orbiculoidea sp.

Orbiculoidea meekana

Schizophoria altirostris

Orthotetes sp. A

Derby/a sp.

Orthotetacean

Linoproductus nodosus

Linoproductus sp. A

Linoproductus pumilus

Productoid

Rhynchonelloid

aff. Anteridocus n. sp.

Composita gibbosa

Composita ovata

Composita subtilita 

Cm Composita sp. 

Cr Crurithyris planoconvexa 

Ao Anthrocospirifer cf A. opimus 

At Anthrocospirifer tanoensis 

An Anthrocospirifer newberryi 

Aa Anthrocospirifer occiduus 

Pu Punctospirifer transversus 

Re Reticulariina gonionota 

di Dielasmid

Bu Buxtonia sp.

FEET

300-

200-

100-

SOU 

ICE 

Ca

FHV 

;be 

nyc 

31)

VEST

rg

>n 

c

~~~~ ——— ---_ C* ^~~~~~ ---_. _

At

>nap 

nyon palnUS Parashant Whitmore 

27) La"y°n Canyon Wash T°!;ow' I W ,^ (n^ Valle

Or,Pc,Bu,Li,Lp,Aa 

Ls,Lp,Cg,Aa

Sc,Lp,p,Cm,At L,Sc, De,Cg,At,R6 -

~ —— — — — _ _ _

De,Co,At.Pu

21

_

oNORTHE 

Jap Tucku 

V Canyc 

(18)

Om,p,At

Co,At,Pu,Re 

Ot,Co>\t,Pu 

Ot,Co,At,Pu

-

AST

P 

>n

Om 

At

De,Cm,Pu

WEST

Gu 

Ca 

(2

ano Quarter- Twin Springs 

TM master CanY°n Nc 

6) (26a) 25 C£

-

-

"

0 

Pe

i,C 

J,C

o,At,An 

o,Cr

Li,Aa

M I

0,3,A

; Sc,Cs

Of PC At An

tio 

my 

(15

—o-*-

-

EAST 

ial Havasu 

an Canyon 

(14)

At,

A Pn C*r\ At r\i

~

20 MILES

FIGURE E1.—Brachiopods of the Watahomigi Formation, western Grand Canyon region, Arizona. Numbers in parentheses are those of

measured sections. Fossil determinations by Mackenzie Gordon, Jr., and R. E. Grant.
80 THE SUPAI GROUP OF GRAND CANYON

in the Watahomigi Formation; it is recorded from four 

localities (fig. El), the easternmost of which is Pica, about 

10 miles southeast of the Blue Mountain section.

A small species of Anthrocospirifer, referred to the 

species A. tanoensis, is very common in the Watahomigi 

Formation and mostly occurs lower in the section than the 

larger form, A. occiduus. Considerable numbers of the 

small species are associated with Composita, Derbyia, and 

other braciopods in the lower half of the formation at nine 

of the localities examined (fig. El). Other species of Anthrocospirifer in the formation are A. newberryi and A. cf. 

opimus (Hall) (fig. El).

Linoproductus nodosus is recorded from two localities, 

in the middle third of the formation. Because its stratigraphic range is believed limited to the uppermost part of 

the Morrowan, it is a significant time indicator. A closely 

related form L. sp. A has been recorded from two additional localities at a slightly lower horizon.

Other genera and (or) species of brachiopods found only 

in the Watahomigi Formation are Linoproductus pumilus, 

Punctospirifer transversus, and Schizophoria altirostris sp. 

Two genera of inarticulate brachiopods also occur in the 

Watahomigi. These are Orbiculoidea and a linguloid form. 

They are found in the middle part of the formation, the 

Orbiculoidea ranging from central to western Grand Canyon (fig. El). The genera Derbyia, at four localities, and 

Orthotetes, at three localities, among the largest and most 

prominent of the brachiopods, are also widespread, having 

been collected in moderate numbers from Toroweap in 

central Grand Canyon westward to the Grand Wash 

Cliffs.

Many kinds of gastropods occur in the Watahomigi Formation, especially in the central part of Grand Canyon 

from where specimens representing 15 genera have been 

determined by E. L. Yochelson and associates (fig. E2). 

Farther west in the region, on and near the Grand Wash

NORTH

Hidden

Canyon

(30)

Pigeon

Wash

(28)

SOUTH 

Snap

Canyon 

(27)

B,En,S,su

EXPLANATION

Eu

B

Re

b

S

Ba

Wo

Sh

Euphemites ? sp.

Bellerophon sp.

Retispira sp.

Bellerophontacean

Straparollus sp.

Baylea sp.

Worthenia? sp.

Shansiella sp.

En

P

Mi

St

Na

n

Ta

An

Euconospira sp.

Pleurotomariacean

Microdoma sp.

Strophostylus sp.

Naticopsis sp.

Neritacean

Taosia? sp.

Anomphalus sp.

su

Ms

D

h

I

Subulitid 

Meekospira sp. 

Donaldina sp. 

High-spired gastropod 

Low-spired gastropod

FEET -400

-300

-200

-100

NORTHWEST 

Guano QuarterCave master 

(26) (26a)

B?, - 

S

Separation

Canyon

(34)

SOUTHEAST

Hindu

Canyon

(35)

SOUTHWEST

Iceberg

Canyon

(31)

.b S Ba Ld Re,S,Ba,Na,An,Mi,D

En, Mi'

20 MILES

Snap

Canyon

(27)

Andrus

Canyon Parashant whitmore 

(24) Canyon Wasn 

(23) (22)

S.P

WEST

National

Canyon

(15)

EAST

Havasu

Canyon

(14)

^-3,Ba,Eu,Wo,Sh,En, 

p,Na,n,Ta,Ms,h

Toroweap

Valley

(21)

NORTHEAST

Tuckup

Canyon

(18)

Re_

FIGURE E2.—Gastropods of the Watahomigi Formation, Grand Canyon region, Arizona. Numbers in parentheses are those of measured sections.

Fossil determinations by E. L. Yochelson.
DISTRIBUTION AND AGE OF FAUNA AND FLORA 81

Cliffs, some additional genera have been recognized as 

well as a few of those of the central area, but, in general, 

gastropods are less numerous in western than in central 

Grand Canyon. Most numerous and also most conspicuous in the thick beds of limestone in western sections is 

Bellerophon sp.

Pelecypods, represented by nearly as many genera as

the gastropods, probably are equally common in the 

Watahomigi Formation of central and western Grand Canyon (fig. E3). Myalina, Aviculopecten, and Schizodus are 

most widespread and apparently flourished in the same 

near-shore, shallow-water environment as that occupied 

by the gastropods and certain of the brachiopods.

Pelecypods of a fauna! assemblage from 12 ft above

NOR' 

G 

(

FHWEST 

uano 

:ave Sep 

(26) Ca

Se,Sc,Sb

Py

SOUTHEAST 

aration Hindu

3T Can*°n

J4[ (35)

_

Se,Le,Ag 

Nu,Pr,Se, ^ J Nu,Pa,Ph,Se,LeAq,A,P

NORTH

Hidden

Canyon

(30) SOUTH

Pigeon 

Wash Canyon 

(28) (27)

My,Ag,Sc,Sa,Sb,Wi 

My,Le,A,Sa,P

Se,Sc,Sa,Sb

Pr,My,Sm,Se,A, 

Sc,Sa,Sb,Or,Wi

SOUTHWEST

Iceberg

Canyon

31

^— -^ Ca"y°n Canyon Pwashant Whitmore Toroweap N °^ 

^^•-^. (27) (24) Canyon Wash v „ K ru 

—^ ^ (23) (22) VJlV Ca

Se,Sc,Sa,Sb

Pr,My,Sm,SeASc,Sa,Sb,Or,Wi

~-^i

P,A

- My,Ag,A md,Ag

-

:

' (

Pr,My,md,Ag

A 

Le,A

WEST

eberg

anyon

31) Guano Quarter- Twin EAST

--.^ Ca\e master Springs National 

^-—__ < 26> ,(26a) (25) Canyon ~~"~— --^

— Se,S

Py

I

Se,S

c,Sb

(15)

^ Se,A,Sa,P,in SP

20 MILES FEET 

300-

200

100

0

EXPLANATION

Nu Nuculopsis sp.

Pa Palaeoneilol sp.

Py Paleyoldia sp.

Ph Phestia sp.

Pr Promytilus sp.

My Myalina sp.

Sm 'Selenimyalinal sp.

Se Septimyalina sp.

md Myalinid

Le Leptodesma sp.

Ag Aviculopecten gravidus

A Aviculopecten sp.

Sc Schizodus amp/us

Sa Schizodus sp. A

Sb Schizodus sp. B

Or Oriocrassatellal sp.

P Permophorus sp.

Wi Wi/kingia sp.

in Pelecypods, indet.

FIGURE E3.-Pelecypods of the Watahomigi Formation, Grand Canyon region, Arizona. Numbers in parentheses are those of measured sections.

Fossil determinations by John Pojeta, Jr., and Mackenzie Gordon, Jr.
82 THE SUPAI GROUP OF GRAND CANYON

the base of the Watahomigi at National Canyon have been 

examined by John Pojeta, Jr. who recognized six taxa. On 

the basis of his study, several conclusions on the paleoecology were reached (John Pojeta, Jr., written commun., 1971) 

as follows: (1) "the assemblage is overwhelmingly 

dominated by the byssally-attached, suspension-feeding 

genus Septimyalina" of which more than 80 specimens 

were included; (2) the second most numerous form (10 

specimens) was Aviculopecten, which likewise was an epifaunal, byssate, suspension feeder; (3) the other genera 

represented—"Schizodus, Sphenotusl, Edmondial, and 

Permophorus—were all shallow infaunal burrowing suspension feeders."

Fragments of echinoderms, especially crinoids and echinoids, are very common in some bioclastic rocks of the

SOUTHWEST

Iceberg

Canyon

(31)

Watahomigi Formation, but complete specimens of these 

animals have not been reported. Corals, although common 

in some of the upper formations of the Supai Group, seem 

to be lacking in the Watahomigi, except at Toroweap 

where a Michelinia was found and at Parashant with a Syringopora (fig. E4). Conulariids are recorded from two 

localities and nautiloids from one (fig. E5).

Associated with assemblages of brachiopods in the central parts and, to a less extent, the western part of Grand 

Canyon are bryozoans, represented in the Watahomigi by 

seven genera (fig. E6). Individual specimens are relatively 

uncommon in the formation, but at Toroweap five different forms were recognized at one horizon.

Trilobites seem to be relatively common in the Watahomigi Formation of central and western Grand Canyon,

r> Andrus ~~~"~---_ — 

uanyon Parashant w --^ n-i\ Canyon • " a" iai11 vv ^-— ~. \*'i / 5 iv Canyon 

^^— ___ U (23)

Un 

_ Un

- Pa

Pa Un

-

Un

Pa,Sy 

Pa

litmore j0 

i/Vash \ 

(22)

Pa

Valley '

NORTHEAST

Tuckup 

Canyon

Pa 

M

WEST

Iceberg

Canyon

(31)

Un 

Un

Guano 

Cave

, . _ . Twin Springs

Canyon 

(25)

Un,Pa

Pa

EAST

National

Canyon

(is

Pa

;dDi,Un

Separation

Canyon

(34)

20 MILES

_J

EXPLANATION

Di 

Pa 

Un 

H

Trilobites

Ditomopygel sp. 

Paladin sp. 

Librogenae indet. 

Hypostome indet.

Sy 

M

Corals

Syringopora sp. 

Michelinia sp.

FEET 300-

200 -

100 -

0 -1

FIGURE E4.—Trilobites and corals of the Watahomigi Formation, Grand Canyon region, Arizona. Numbers in parentheses are those of measured 

sections. Trilobite determinations by R. E. Grant and others; coral determinations by W. J. Sando.
DISTRIBUTION AND AGE OF FAUNA AND FLORA 83

NORTHWEST 

Iceberg 

Canyon

FEET 

400 -

^

SOUTHEAST 

Quartermaster 

(26a)

200 -

100 -

o -J

NORTH

Hidden

Canyon

(30)

Hindu

Canyon

(35)

3t,R

Pigeon 

Wash 

(28)

SOUTH 

Guano

Cave

(26)

R,Tr, 

St,Fe

v\

Wh 

V

/EST

Jmore Toroweap ^ Vash v M v Tucku

(22) TMY Canyo 

1 ' (18)

^\ XC

/EST

ridr 

any 

24

.

us 

on Pa

c

--,

Tr,R

E 

rashant Whitmore T 

anyon Wash ' °r. 

(23) (22) v(

- St

" — — ~~ — — _ '

Fi,Tr

AS

ow 

alle 

21)

-

=

T 

3ap

y

St,R

Fi,St,Tr,Fe,R 

Fe,R,Cy

20 MILES

FEET 

400

300 -

2DO100-

Q _

SOU'

N< 

C<

FHW

Jtion 

anyo 

(15) 

-^^~

s-\^

COT

D NORTHEAST

al Havasu 

Canyon

I (14) (

C

'~X_—

EXPLANATION 

B Bryozoan, undif. Fe Fenestella sp.

20 MILES

EXPLANATION

C Conulariid L Liroceras(l)

coiled nautiloid

FIGURE E5.—Conulariids and nautiloids of the Watahomigi 

Formation, Grand Canyon region, Arizona. Numbers in parentheses are those of measured sections.

in contrast to their rarity or absence in overlying formations of the Supai. At 10 localities (fig. E4) they have been 

collected and two genera are recognized.

The only marine vertebrate represented in the Watahomigi Formation is the shark Deltodus. Isolated teeth of

Fi Fistuliporoid 

St Stenoporoid 

Tr Tropostome

P Polypora sp. 

R Rhomboporoid 

Cy Cystodictyal sp.

FIGURE E6.—Bryozoans of the Watahomigi Formation, Grand Canyon 

region, Arizona. Numbers in parentheses are those of measured 

sections.

this animal have been found at the Parashant Canyon, 

Guano Cave, and Separation Canyon sections and a spine 

fragment at Toroweap Valley (fig. E7).

The microfauna of the Watahomigi Formation has been 

examined and studied by Bernard Mamet at the University 

of Montreal. He recognized 17 kinds of small forams, associated with four types of algae (table El). Eleven of the 

foraminifers have been found in younger units of the Supai 

but 6 have not.

Of particular interest among the microfossils reported 

on by Bernard Mamet are the forms Neoarchaediscus parvus, N. incertus, and Asteroarchaediscus sp., all of which 

occur exclusively in the lower half of the Watahomigi Formation in a distinctive pelletoidal-oncolithic facies and, according to Mamet (written commun., 1972), are suggestive 

of a Morrowan to Atokan age.

Conodonts of this formation have been recorded in 

Grand Canyon thus far only from the Separation Canyon
84 THE SUPAI GROUP OF GRAND CANYON

NORTHWEST

Iceberg

Canyon

(31)

WEST

Snap

Canyon

(27)

SOUTHEAST

Guano 

Cave 

(26)

Separation

Canyon

(34)

Hindu

Canyon

(35)

FEET 

400

-300

-200

- 100

-DD

Canyon 

(23)

Whitmore

Wash

(22)

-D

Toroweap

Valley

(21)

EAST

Tuckup

Canyon

(18)

- D

10 20 MILES

_J

EXPLANATION 

D Deltodus sp.

FIGURE E7.—Sharks teeth and spine fragments of the Watahomigi Formation, Grand Canyon region, Arizona. Numbers in parentheses are those of

measured sections. Fossil determinations by D. H. Dunkle.

locality. There they have been noted at three horizons—32, 

68, and 104 ft above the base—and are represented by four 

genera (table E2). Probably they occur elsewhere in the 

area, but as yet have not been observed in any collections. 

Concerning the Separation Canyon assemblage, }. W. 

Huddle (written commun., 1970) stated: "The only significant species is Cavusgnathus gigantus, which ranges from 

Late Mississippian to Permian. An Early Pennsylvanian 

age is reasonable."

West of the Grand Canyon region—at Lime Ridge and 

Pakoon Ridge—conodonts have been collected by Walter 

Pierce (written commun., 1976) at various horizons that he 

considered to be correlatable with the lower and middle 

parts of the Watahomigi. These specimens were examined 

by George }. Vervile who recognized 15 different genera, 

including the 5 recorded by Huddle from Separation Canyon. The collections by Pierce were assigned a Morrowan 

age by Vervile (Walter Pierce, written commun., 1976).

The abundance of certain brachiopod groups and various molluscs and the near absence of corals and many 

types of foraminifers probably is, at least in part, related to

TABLE E2.—Conodonts of the Watahomigi Formation (below Atokan 

conglomerate) at Separation Canyon

[Determined by). W. Huddle]

Horizon (feet 

above basel Determination

No. of 

specimens

32

68

104

Cavusgnathus gigantus Gunnell 

C. sp. (broken specimens) .... 

Bar fragments ..............

Cavusgnathus sp. (broken specimen) 

Bar fragments ..................

Cavusgnathus sp. ..................

C? sp. ..........................

Hindeodella sp. ...................

Spathognathodus cf. S. minutus Ellison 

Synprioniodina sp. ................

Bar fragments ....................

4

5

10

1

4

1

1

2

1

1

5

the lithofacies. As shown in figure CIO, this formation, 

unlike those higher in the Supai Group, consists of much 

mudstone and limestone but contains very little sandstone. 

The general lack of cross-bedding and the relative abun-
DISTRIBUTION AND AGE OF FAUNA AND FLORA 85

dance of fine sediments suggest that low-energy conditions 

prevailed.

A synthesis of the distribution and abundance of 

fossils in the Watahomigi Formation of Grand Canyon 

emphasizes certain major differences between assemblages 

in this formation and those of younger units in the Supai. 

Brachiopods of several groups are numerous and both 

gastropods and pelecypods are locally abundant, whereas 

these faunal groups are relatively uncommon in the overlying formations.

MARINE FAUNA OF THE 

MANAKACHA FORMATION

Invertebrate fossils of all types are sparse in the Manakacha Formation. This is in contrast to the relatively abundant marine assemblage of the underlying Watahomigi 

Formation where numerous species and many individuals 

occur. Six groups of megafossils, all of them from western 

Grand Canyon, are represented in the Manakacha collections made during this study. Included in these groups are 

three genera of brachiopods, two of bryozoans, two of 

pelecypods, and a single genus each of gastropod, trilobite, 

and coral (fig. E8).

Among the brachiopods of the Manakacha is a small 

form of Anthrocospirifer that is very numerous in the upper part of the slope unit of the formation at Pigeon Wash 

(fig. E8). Probably the most common and widespread of 

the megafossils, however, is a large species of Bellerophon 

found in all sections along the Grand Wash Cliffs (figs. E8, 

E9).

Most diagnostic and also most widespread of the marine 

invertebrate fossils in the Manakacha Formation are the 

fusulinids, distributed throughout most of the Grand Canyon area (fig. ElO). Although individuals are not extremely 

common, the group is represented by the following five 

genera (fig. Ell): Fusulinella, Profusulinella, Staffella, 

Pseudostaffella, and Eoschubertella. These fusulinids are 

the principal means of establishing an Atokan age for the 

formation. Representatives of these genera have been 

found in the Manakacha at Hidden Canyon, Pigeon Wash, 

and Parashant Canyon in the west and at Hermit Trail, 

Grandview Trail, and Eminence Fault in the east.

The presence of Fusulinella sp. at Kaibab Trail, north, 

and at Grandview Trail and of Pseudostaf fella sp. at Kaibab Trail, north (fig. Ell), at an horizon seemingly below 

the lower boundary of the formation, suggests that rocks 

of Atokan age begin in the Watahomigi Formation.

Small foraminifera seem to be widely distributed in the 

formation, and are most common in the western part of 

Grand Canyon. They have been examined by Bernard 

Mamet who recognized (written commun., 1972) 13 genera 

including a number of endothyrid species (table El). These 

various foraminifers have been assigned by Mamet to four

principal microfacies and he stated that these facies are 

readily distinguished by their petrographic characteristics. 

The various small foraminifers, however, do not seem to 

be restricted to single time-rock units, but commonly occur 

in two or more formations as seen on Grand Canyon profiles. Associated with them in some places are calcispheres 

and other algae, and some fusulinids.

The presence of Endothyra media Waters and "E." teres 

St. Jean among the foraminifers is said by Mamet (written 

commun., 1972) to indicate a Des Moinesian (or slightly 

younger) age. These species are numerous in the Manakacha Formation, but also occur in the Wescogame (fig. 

E12). In the latter formation they may have been introduced as detrital grains.

MARINE FAUNA OF THE 

WESCOGAME FORMATION

The Wescogame Formation, like the underlying Manakacha, contains an impoverished fauna (fig. E13), but one 

that is widely distributed (fig. E14). This probably is the 

result of a high-energy depositional environment, dominated by highly cross-stratified, limy sand that was hostile to 

most marine life. Brachiopods have not been found in the 

Wescogame Formation, bryozoans are not recorded, and 

corals, except for two forms from Hidden Canyon, are not 

represented.

Most numerous of the megafossils, at least locally, are 

the pelecypods (fig. E15). In limestone of the Guano Cave 

section they are represented by six genera (fig. E13). Gastropods, especially large bellerophontidae, are common in 

aphanitic limestone at Hidden Canyon. None of these mollusks are in the sandy cross-bedded limestones or calcareous sandstones, however, and they apparently favored a 

quiet-water environment.

Sharks teeth, referred to Deltodus sp. by D. H. 

Dunkle, are recorded from two localities—Hidden Canyon 

and Iceberg Canyon (fig. E13). Their presence in a sandy 

environment is not surprising as they represent swimming 

animals. Likewise, the occurrence of fusulinids and 

numerous smaller foraminifers may be at least partially accounted for by the ease with which they could be 

transported in high-energy waters inferred from the crossbedded detrital sand in which they occur.

A Late Pennsylvanian (Virgilian) age has been assigned 

to rocks of the Wescogame Formation in Grand Canyon 

on the basis of the fusulinid Triticites sp. and the corals 

Syringopora multattenuata McChesney and Canina sp. 

(W. J. Sando, written commun., 1964). Further support of 

this assignment is furnished by the presence of Ozawainellal sp. from three collections made at 49 ft below the top 

of the formation at Hidden Canyon. "A considerable 

number of shells are present," according to L. G. Henbest 

(written commun., 1964).
86 THE SUPAI GROUP OF GRAND CANYON

NORTH

Hidden

Canyon

(30)

Pigeon

Wash

(28)

SOUTH 

Snap

Canyon 

(27)

Brachiopods

Ac,Sc 

Ao

Ac 

Ac

NORTH

Hidden

Canyon

(30)

Pigeon

Wash

(28)

SOUTH 

Snap

Canyon 

(27)

Gastropod

-B

NORTH

Hidden

Canyon

(30)

Pigeon

Wash

(28)

-R

SOUTH 

Snap

Canyon 

(27)

Bryozoans

NORTH

Hidden

Canyon

(30)

Pigeon 

Wash 

(28)

SOUTH 

Snap

Canyon 

(27)

FEET 

400 •

300 -

200 -

100 -

0 -1

NORTH

Hidden

Canyon

(30)

Pigeon

Wash

(28)

SOUTH 

Snap

Canyon 

(27),

Pel ecy pods

S,N

Trilobite

NORTH

Hidden

Canyon

(30)

Pigeon 

Wash 

(28)

SOUTH 

Snap

Canyon 

(27)

Cn

Coral

20 MILES 

_I

EXPLANATION

Brachiopods: Ao Anthrocospirifer occiduus

Ac Anthrocospirifer tanoensis

Sc Schizophoria sp.

Bryozoans: R Rhomboporoids, etc.

T Tabulipora sp.

Trilobite: P Paladin

Gastropod: B Bellerophon (Bellerophon) n. sp.

Pelecypods: S Schizodus sp.

N Nuculopsis sp.

Coral: Cn Caninia sp.

FIGURE E8.—Principal invertebrate megafossils of the Manakacha Formation, western Grand Canyon, Arizona. Numbers in parentheses are those 

of measured sections. Fossil determinations as follows: brachiopods by Mackenzie Gordon, Jr.; bryozoans by Helen Duncan; gastropods by E. 

L. Yochelson; pelecypods by John Pojeta, Jr.; corals by W. J. Sando.
DISTRIBUTION AND AGE OF FAUNA AND FLORA 87

B

FIGURE E9.—Bellerophon (Bellerophon) n. sp. dorsal (A) and side (6) 

view of large specimen, natural size. Manakacha Formation, USGS 

colln. 22272-FC, from Snap Canyon section, Grand Canyon, Ariz. 

Photograph by Mackenzie Gordon, Jr.

Small (nonfusulinid) foraminifers of which 14 species, 

including 4 Endothyridae, have been recognized by Bernard 

Mamet (table El), seem to have had their distribution determined by microfacies rather than by age factors. Thus, 

many of the genera represented in the Wescogame Formation likewise are found in other formations of the Supai 

Group where similar microfacies occur.

MARINE FAUNA OF THE 

PAKOON LIMESTONE

The uppermost formation of the Supai Group, the Esplanade Sandstone, is largely barren; however, its lateral 

equivalent to the west, known as the Pakoon Limestone 

(McNair, 1951), is a relatively pure carbonate rock and is 

highly fossiliferous. The Pakoon is exposed along the

EXPLANATION 

Eo Eoschubertella 

Fu Fusulinella

Profusulinella

Pseudostaffella

Staffella

36°-

FIGURE E10.—Distribution of fusulinids of Atokan age (Manakacha Formation and upper part of the Watahomigi Formation), Grand Canyon

region, Arizona. Fossil determinations by R. C. Douglass.
88 THE SUPAI GROUP OF GRAND CANYON

SOUTHWEST

Hermit

Trail

(9)

Grandview

Trail

(6)

Eo 

Fu 

Pr 

Ps 

St

Fu

Manakacha

Watahomigi

Formation

Fu,Ps

Fu~~ 

Formation

EXPLANATION 

Eoschubertella sp. 

Fusu/inella sp. 

Profusulinella sp. 

Pseudostaffelta sp 

Staffella sp.

NORTHEAST

Eminence

Fault

(3)

FurPs

NORTH

Kaibab Trail,

north

(8)

SOUTH

Grandview

Trail

(6)

Manakacha Formation

Fu,PsWatahomigi Formation

Fu,Ps 

Fu

FEET 

r 400

-300

-200

-100

-0

p

V DRTH

idden ___^_- 

anyon ___^— — ' 

(30) ^^

-

*~\

Eo

Manakacha Formation

Fu

geo 

t/asl 

28)

-

-

r\ ,

n SC 

i S 

Ca 

Tu,St^

Fu 

Fu

Pr

Eo

)UT 

>na[ 

nyc 

27)

-"X^~

-

^ ,-

H

3

n

Eo

20 MILES

Snap

Canyon

(27)

^sFHWEST ^^ 

eberg ^^

anyon ^^

3^0

-~\ x-

^^

Eo

- — —x-

-

^ ^>

^^^-^^^ Twin Springs

^^-^^ Ca. nV°n NORTHEAST 

^^— ^_ _ ^^b' Parashant

Manakacha Formation

Eo

--x%—

-

^^ ^

—— — — _ _ Canyon ~^~~ — — — ~^__ _

Eo

23)

-

-

^A s

Eo

Eo

FIGURE Ell.—Horizons of fusulinids of Atokan age in Grand Canyon measured sections, Arizona. Numbers in parentheses are those of measured

sections. Fossil determinations by R. C. Douglass.

Grand Wash Cliffs at the western end of Grand Canyon; it 

was studied in this area at Hidden Canyon, Pigeon Wash, 

and Snap Canyon, and to the southwest at Iceberg Canyon. A partial section was examined at the Guano Cave 

locality, south of the Colorado River. At all of these sections large faunas were collected.
DISTRIBUTION AND AGE OF FAUNA AND FLORA 89

114° 113° 112'

__JJTAH__ 

ARIZONA

EXPLANATION 

Em Endothyra media 

Et E. teres

Q

FIGURE E12.—Distribution of Endothyra media and £. teres in upper part of the Manakacha Formation and lower part of the Wescogame Formation, Grand Canyon region, Arizona. Fossil determinations by Bernard Mamet.

Eastward in the Grand Canyon area the carbonate rocks 

of the Pakoon are represented only by the thin tongues of 

limestone that extend into highly cross-stratified sandstones of the Esplanade. The only fossils that have been 

found in these strata of sandstone are bioclasts (fig. E16) 

that cannot be identified specifically.

The fauna of the Pakoon consists chiefly of corals, fusulinids, and smaller foraminifers. These were abundant and 

varied at all of the localities examined, and were accompanied by some brachiopods, gastropods and fragments of 

echinoderms. Sharks teeth were found at two places (fig. 

E17) and an unidentified bryozoan at one (fig. E17).

The coralline material in the Grand Canyon collections 

was studied by W. J. Sando (written commun., March 26, 

1964) who recognized nine genera among 40 specimens 

from four localities (fig. E17). The colonial corals form 

small mounds or bioherms scattered through thick limestone beds at various horizons. They "show affinities 

to the Lower Permian faunas *** from the Ely area,

Nevada," according to Sando.

Six genera of fusulinids (fig. E18) have been identified in 

rocks of this formation, and they include some, such as 

Schwagerina and Pseudoschwagerina, that serve to establish the Wolfcampian age of the strata, and others, including Triticites and Schubertella (fig. E19), that are common in Lower Permian rocks elsewhere in the region. As 

yet no fusulinids have been found in the Esplanade to establish whether or not it is precisely equivalent in age to 

the Pakoon; apparently the cross-bedded sand represents 

an environment unfavorable to most marine life.

A collection of small foraminifers of the Pakoon Limestone at Iceberg Canyon was examined by L. G. Henbest 

(written commun., 1964) who recognized the following 

forms of Early Permian or probable Early Permian age: 

Geinitzinal sp., Spandelinoidesl sp., and Calcivertella sp. 

All of these were from 24 ft above the base of the Pakoon 

Limestone.

Microfacies of type 4 of Bernard Mamet (written com-
90 THE SUPAI GROUP OF GRAND CANYON

NORTHWEST

Iceberg

Canyon

(30)

SOUTHEAST

Guano

Cave

(26)

Pelecypods, gastropod

NORTH

Hidden

Canyon

(30)

Pigeon

Wash

(28)

A, P, S, Pr, Se,St,M,L, B

SOUTH 

Snap

Canyon 

(27)

Corals

Cn,Sy

NORTH

Hidden

Canyon

(30)

Pigeon

Wash

(28)

Tr

Tr

NORTH

Hidden

Canyon

(30)

Fusulinids Sh 

Sh

Pigeon

Wash

(28)

Sharks teeth

FEET 

^400

-300

-200

-100

NORTHWEST 

Iceberg 

Canyon

(31)

SOUTH 

Snap

Canyon 

(27)

Fusulinid

SOUTHEAST 

Guano 

Cave 

(26)

Sh

SOUTH

Snap

Canyon

(27)

WEST

Iceberg

Canyon

(31) EAST

Snap

Canyon

(27)

Sharks teeth

20 MILES

Pelecypods:

Gastropod: 

Corals:

Fusulinids: 

Shark:

M

L

A

S

Se

P

Pr

St

B

Cn

Sy

Tr

Sh

D

EXPLANATION 

Myalina sp. 

Leptodesma sp. 

Aviculopecten sp. 

Schizodus sp. 

Septimyalina sp. 

Permophorus sp. 

N. gen. aff. Promytilus 

Strebloteria sp. 

Bellerophon (Bellerophon) 

Caninia sp. 

Syringopora, type 2 

Triticites sp. 

Schubertella sp. 

Deltodus sp.

FIGURE El3.—Principal marine fossils of the Wescogame Formation, Grand Canyon region, Arizona. Numbers in parentheses are 

those of measured sections. Fossil determinations as follows: pelecypods by John Pojeta, Jr.; corals by W. J. Sando; fusulinids 

by R. C. Douglass; sharks teeth by D. H. Dunkle.
DISTRIBUTION AND AGE OF FAUNA AND FLORA 91

FIGURE E14.—Pelecypods from the Wescogame Formation: A-D, Aviculopecten sp., enlarged view and view 

natural size of left valve (USNM 256853) and views of two other left valves (USNM 256854 and USNM 

256855); E, F, N. gen. aff. Promytilus, n. sp., views natural size and enlarged of left valve (USNM 256856); C-L, 

Permophorus sp., views natural size and enlarged of two right valves (USNM 256857 and USNM 256858) and 

one left valve (USNM 256859). All specimens from USGS colln. 24774, Guano Cave measured section, Grand 

Canyon, Ariz. Photographs by Mackenzie Gordon, Jr.

mun., 1972) is "identified on the abundance of mud-filled 

small fusulinids, and small forams that are almost exclusively attached forms." This microfacies, where it occurs in 

the Pakoon Limestone, contains the following foraminifers: Biseriamminds, Diplosphaerina sp., Endothyra sp., 

and Pseudoendothyra sp.

Four genera of brachiopods have been recognized in the 

Pakoon Limestone of the western Grand Canyon area. 

Two of these—Composite sp. and a chonetid—are numerous at several localities, but the only other brachiopods 

recorded are a species of Derbyia and one of Linoproductus (fig. E20). Mollusca are represented by four genera, 

all from a single zone at the Guano Cave locality (fig. E17).

TRACKS OF VERTEBRATE 

ANIMALS OF THE 

WESCOGAME FORMATION

In at least four localities in the eastern end of Grand 

Canyon, tracks and trails of vertebrate animals are preserved on foreset beds of the Wescogame Formation. The 

original discovery, in 1915, was by Charles Schuchert 

(1919, p. 357) at a site about one-half mile below Santa 

Maria Spring on the Hermit Trail. Subsequently, fossil

footprints were found at a lower horizon, "below Breezy 

Point," on Hermit Trail and also near O'Neill Butte on the 

Kaibab Trail, south (figs. E2IA, B, E22B) (Gilmore, 1927, 

p. 8). Still later, tracks were discovered by G. E. Sturdevant 

in the Supai along the Bright Angel Trail (Gilmore, 1927, 

p. 9) and at about the same horizon on the Kaibab Trail, 

north (Gilmore, 1928, p. 3).

During the course of fieldwork in central and western 

Grand Canyon conducted during the 1950's, trackways of 

small vertebrate animals were found by the writer in slabby 

sandstones of the Wescogame Formation at several localities. In the Parashant Canyon section a series of seven or 

eight footprints preserved on the surface of a slab from a 

very limy cross-bedded sandstone was photographed (fig. 

E22A); tracks also were recorded in this formation in Andrus Canyon and S B Canyon. At Andrus they were on a 

ripple-marked surface.

The Supai (Wescogame) trackways, according to Gilmore (1927, p. 73) represent "an ichnite fauna new to 

North America." He stated that it is uncertain whether the 

animals that made them were reptiles or amphibians, but 

they were quadrupedal creatures whose tracks show no 

close relationship to those from any other known locality, 

and are "Carboniferous in aspect." Not a single genus or 

species found in the Supai also occurs in the Hermit Shale 

or Coconino Sandstone—doubtless because those formations represent very different environments.
92 THE SUPAI GROUP OF GRAND CANYON

114'

36°-

FIGURE E15.—Measured sections from which clasts of marine fossils have been obtained in the Wescogame Formation, Grand Canyon region,

Arizona.

The known ichnite fauna of the Wescogame as described 

and named by Gilmore (1927, p. 8, 10) consists of four 

genera and species of vertebrates as follows:

Anomalopus sturdevanti .....

Stenichnus yakiensis .........

Tridentichnus supaiensis .....

Ammobatrachus turbatans ...

Kaibab (Yaki) Trail, south. 

Kaibab (Yaki) Trail, south. 

Hermit Trail, Kaibab Trail, south. 

Bright Angel Trail.

The trailways of two varieties of invertebrate animals from 

the Kaibab Trail, south, were described and illustrated 

(Gilmore, 1928, p. 10-13, pi. 4, 5) but not named.

Recent studies by Haubold (1975, p. 131) of tetrapod 

footprints have indicated that "the stratigraphically important evolution of amphibians and reptiles universal in the 

late Paleozoic" is illustrated by identical evolutionary sequences in fossil faunas of many isolated and widely separated sections in central Europe and in North America. In 

this connection, Haubold (1975, p. 121) briefly referred to 

the track fauna of the Supai with its distinctive characteristics, its associated flora, and its relation to the European 

sequence.

In ichnological studies made of footprints from the 

Lower Permian Cutler Formation of southwestern Colorado, Baird (1965, p. C48-C49) referred one form to 

"Genus indet., cf. Brachydactylopus Toepelman and 

Rodeck, 1936," and stated that it is similar to Tridentichnus supaiensis Gilmore (which he considered synonymous with Ammobatrachus turbatans Gilmore, also from 

the Supai). These forms, together with species described 

from the "Permo-Carboniferous Fountain formation of 

the Colorado Front Range" and the "Upper Pennsylvanian (Rock Lake formation, Virgilian) of Garnett, Kansas" 

were referred by Baird to the form-family Korynichniidae. 

The Korynichniid footprints were correlated by Nopcsa 

(1923) and by Lotze (1928) with diadected cotylosaurs, and 

Baird (1965, p. C49) presented evidence in support of this 

correlation.

The nature of the animals that made the Wescogame 

tracks is unknown, for not a single bone or skeletal fragment has yet been found in the formation. In an attempt to 

identify some of the tracks in terms of vertebrate skeletons 

from other regions, Gilmore (1927, p. 73) made tracings
DISTRIBUTION AND AGE OF FAUNA AND FLORA 93

114a 112°

37<

36<

UTAH

ARIZONA \

#' 

&

$

< <

s^

< O

> ^

Hidden 

x Canyon

Grand

Gulch

X Mine

-§

c\

$1 House Rock Canyon

.( x Thunder River Trail i L"

SB Canyon x ^

A

Q iParashanV VWhitmore Q 

^?P._ Vcanyonj N Wash ^

Andrus\ ^ \/0 y^ HaV3SU 

Canyon 

x Prospect Valley

r

Springs

/ \Blue Mountain Canyon \ x •-— "--

10 20 30 MILES

FIGURE E16.—Measured sections in the Grand Canyon region, Arizona, from which clasts of marine fossils have been obtained in the Esplanade

Sandstone and intertonguing Pakoon Limestone (McNair, 1951).

"of the fore- and hind feet of animals" to compare with the 

Supai tracks, but results were unrewarding.

The species Anomalopus sturdevanti apparently had a 

heavy body and very short legs, for the footprints are close 

together. A specimen described by Gilmore (1927, p. 70, 

pi. 20) shows "portions of the forefoot track *** destroyed 

by the hindfoot partially stepping upon it." The same feature is illustrated by a set of tracks in situ along the Kaibab 

Trail, below and east of O'Neill Butte, where many Grand 

Canyon visitors see it today (fig. E22B). This trackway, 

like most of those in the Wescogame Formation, is "ascending the slope of cross-bedding," which has a steep dip 

and apparently caused the animal to walk slowly and deliberately, leaving deeply impressed and clearly defined 

prints (Gilmore, 1927, p. 20).

In experiments conducted in the mid-1970's by Leonard 

Brand of Loma Linda University, California (written commun., 1977), footprints made under water by a large amphibian showed many of the same features displayed in 

some of the Wescogame trackways. In a photograph (fig. 

E21C) kindly furnished by Brand, the prints are seen to be 

overlapping each other and to display various degrees of

clarity or sharpness depending on the state of saturation or 

lack of cohesiveness of the sand at different positions on 

the slope.

TRACKS OF VERTEBRATE 

ANIMALS OF THE 

ESPLANADE SANDSTONE

Some peculiar tracklike markings having "superficial resemblance to tracks made by horses hoofs" were recorded 

by Gilmore (1926, p. 37) from "a massive sandstone of the 

Supai formation [Esplanade Sandstone] in that part of 

Grand Canyon known as 'Fossil Bay' " northeast of 

Havasu Canyon. These markings are illustrated, described 

in some detail, and discussed by Gilmore who stated that 

the Supai Indians "regarded them as tracks made by a band 

of horses."

The similarity to the imprints of horse's hoofs noted in 

the markings at Fossil Bay, with their semi-oval forms, 

posterior extremities prolonged backward, and their round
94 THE SUPAI GROUP OF GRAND CANYON

NORTHWEST

Iceberg

Canyon

(31)

SOUTHEAST

Separation

Canyon

(34)

NORTH

Hidden 0 1Q , 

Canyon Pigeon i i

(30) Wash

-

-

-

(28) Snap

Sy-1,KI 

Corals

Di,Bo,Co,Sy-2,He 

Di

Di

-

\ ^n SOUTH

Di ^

-

-

Twin Springs 

^^7^7~~^— Canyon

Kl ^~~~^ ——

Du,Li,Th,He __^—-^"^^ Du ____-— --^"^

^b

0 MILES

FEET

r 400

EXPLANATION 

CORALS

Li Lithostrotionella 

Di Diphyphyllum 

Co Columellate coral 

Kl Kleopatrina 

He Heintzella 

Sy-1 Syringopora, type 1 

Sy-2 Syringopora, type 2 

Bo Bothrophyllum 

Du Durhamina 

Th Thysanophyllum

BRYOZOANS

B Bryozoan, undif. 

SHARKS

C Cladodus

D Deltodus 

GASTROPODS

Eu Euphemites

M Meekospira

K Knightes

PI Platyceras

NORTH

suss,

(30) ,A, (&)

Bryozoans

— 300

Snap - ZOO

\ uanyon 

X (27) SOUTH

B

SOUTHWEST 

Iceberg 

Canyon

(31)

\ _^ Twin Springs - 100

~~ ~~— ~~- _ Canyon

^~—— ^___ (25)

NORTHWEST 

Iceberg 

Canyon

(31)

^\^ NORTHEAST

- D "\ Snap

^^ Canyon

-

\ v "

Q

Sharks teeth

-v^>^

/

-— -^

^^-^^

^"~-\ SOUTHEAST

-~~^^ Twin Springs

_ . . Guano ^~^-~. Canyon Gastropods Caye ^^ (25)

/OCV UP; __^i __ ___ _ _ —— —— ——

FIGURE E17.—Corals, bryozoans, gastropods, and sharks teeth oi Pakoon Limestone (McNair, 1951), Grand Canyon region, 

Arizona. Numbers in parentheses are those of measured sections. Fossil determinations as follows: corals by W. J. Sando; 

bryozoans by Helen Duncan; gastropods by E. L. Yochelson; sharks teeth by D. H. Dunkle.

or oval ends all pointing in a common direction, caused 

Gilmore (1926, p. 38-39) to search the literature for 

records of other markings of comparable type. Tracks described as Hoplichnus equus from the Triassic of Connecticut, described by Hitchcock (1858, p. 134), and hooflike

prints named Choliohnus gigas, from the New Red Sandstone of Scotland, described by Jardine (1853, p. 9, H.I) 

were discussed by Gilmore.

During the course of the present investigation, impressions similar in size and general form (fig. E23A, B) to those
DISTRIBUTION AND AGE OF FAUNA AND FLORA 95

NORTH

Hidden

Canyon

(30)

WEST

Iceberg

Canyon

(31)

Pigeon

Wash

(28)

Pakoon Limestone 

Tr,Sc,Ps,Mo,CI

Sc

Sh _____

SOUTH 

Snap

Canyon 

(27)

Sc.Ps

Snap

Canyon

(27)

Tr,Sc

EAST/

Tr,Sc,Sh NORTH 

Andrus 

Canyon 

(24)

Sc,Sh

Sh

Pakoon Limestone

Tr,Sc

Tr,Sc,Sh

SOUTH

Blue Mountain

Canyon

(19)

Sh

Esplanade Sandstone

SOUTHWEST

Twin Springs

Canyon

(25)

Sh

Whitmore

Wash

(21)

Esplanade Sandstone Esplanade Sandstone

NORTHEAST

SB

Canyon 

(17)

Sh

EXPLANATION

Tr Triticites sp.

Sc Schwagerina sp.

Ps Pseudoschwagerina sp.

Mo Monodiexodina sp.

Cl Climacammina sp.

Sh Schubertella sp.

20 MILES

FEET

i- 400

-300

-200

-100

"-0

FIGURE E18.—Fusulinids of the Pakoon Limestone (McNair, 1951) and Esplanade Sandstone, Grand Canyon region, Arizona. Numbers in parentheses are those of measured sections. Fossil determinations by R. C. Douglass.
96 THE SUPAI GROUP OF GRAND CANYON

lUa 112-5

36°

UTAH

ARIZONA

EXPLANATION 

Sc Schubertella 

Tr Triticites

FIGURE E19.—Geographic distribution of Triticites and Schubertella in Esplanade Sandstone and Pakoon Limestone (McNair, 1951), Grand Canyon

region, Arizona. Fossil determinations by R. C. Douglass.

of the Fossil Bay locality were observed on sandstone surfaces of the Esplanade at Hidden Canyon in the extreme 

western part of the region. No information is available on 

the type of animal represented, but the pairing of the impressions, the common directions of orientation, and the 

uniformity of shape, all suggest an origin as trackways of a 

quadrupedal animal.

ABSENCE OF VERTEBRATE 

SKELETAL REMAINS

Although some red beds of Pennsylvanian and Permian 

age, similar at least superficially to those of the Supai 

Group, have produced vertebrate faunas, no skeletal material has yet been found in the Supai of Grand Canyon. 

Even in parts of the Wescogame Formation of Virgilian age 

where numerous trackways of vertebrates occur, no record

of the makers is known.

In red beds of the Cutler Formation in the Monument 

Valley area northeast of Grand Canyon, sizeable vertebrate faunas are found in both the Halgaito and Organ 

Rock Tongues as described by Vaughn (1962, 1964). The 

Halgaito is believed to be of early Wolfcampian age, so 

probably is the time equivalent of the Esplanade Sandstone; the Organ Rock is considered by Vaughn (1964, 

p. 581) on the basis of faunal elements to be probably of 

earliest Leonardian age.

In both the Halgaito and the Organ Rock Tongues, 

fossils "are restricted, with rare exceptions, to streamchannel deposits" and "occur in conglomerates and in 

cross-bedded sandstones immediately above, below, and 

at the lateral edges of the conglomerate" (Vaughn, 1964, p. 

568). In the formations of the Supai Group, probably a 

general lack of stream channels and associated conglomerates precludes the likelihood of finding strata of
DISTRIBUTION AND AGE OF FAUNA AND FLORA 97

NORTH

Hidden

Canyon

(30)

SOUTH

Pigeon

Wash

(28)

SOUTHEAST

Twin Springs

Canyon

(25)

423 Ft

Esplanade Sandstone

Co

Co 

Co 

Ch

Co

Pakoon Limestone

Co,De

Ch 

Co

Pakoon Limestone

NORTHWEST

Iceberg

Canyon

(31)

Co,De

Ch 

Co

SOUTHEAST 

Guano 

Cave 

- (26)

EXPLANATION 

Co Composite sp. 

Ch Chonetid

Derby/a sp.

Linoproductus sp.

De 

Li

Pakoon Limestone

20 MILES

_J

FEET 

-400

-300

^200

-100

L 0

FIGURE E20.—Brachiopods of the Pakoon Limestone (McNair, 1951), western Grand Canyon area, Arizona. Numbers in parentheses are those of

measured sections Fossil determinations by Mackenzie Gordon, Jr., and R. E. Grant.

comparable depositional environments. Most channels in 

the Supai probably mark times of regional hiatus rather 

than intraformational stream erosion, and at least some of 

the associated conglomerates are marine as shown by 

brachiopods within them.

FLORA OF THE SUPAI GROUP

Fragments of land plants are preserved in red-brown 

siltstones and mudstones, scattered through all formations 

of the Supai Group. Along the Kaibab Trail, south, these 

fossils occur in the "lower and middle portions" of the 

Supai, as well as in the Hermit Shale above. They are referred to (White, 1929, p. 10) as "traces of plants including

Walchia and Rivularites *** at several levels" in the redbed sequence.

In the lowest formation—the Watahomigi—an assemblage of land plants consisting of "Walchia, Toeniopteris, 

Neuropteris, Cordarites and Catamites," in fragmentary 

form, is recorded from about 25 feet above the base along 

the Yaki (Kaibab, south) Trail (White, 1929, p. 10). Likewise near the base of the Watahomigi, but along the Hermit Trail "rain pittings and fillings of suncracks," which 

commonly are associated with land plants in the redbrown mudstones, were noted by Schuchert (1918, p. 357). 

Farther west in Grand Canyon, however, at comparable 

horizons in the lower part of the formation, brachiopods 

and other marine fossils constitute the principal traces of 

depositional environment.
98 THE SUPAI GROUP OF GRAND CANYON

FIGURE E21 (above and facing page).—Trackways of vertebrate 

animals in sand and fine-grained sandstone. A, Footprints (each 

about 4 in. long) with long toe marks, on slab from foreset beds of 

sandstone, Wescogame Formation, south section of Kaibab Trail. 8, 

Set of overlapping footprints (each about 4 in. long; compare with C)

of short-legged quadruped moving up 24°-foreset bed, sandstone of 

Wescogame, south section of Kaibab Trail. C, Footprints of amphibian made underwater in modern sand deposit with steep surface dip. 

Photograph by Leonard Brand, Loma Linda University, California.

In the Manakacha Formation, marine fossils of various 

types constitute a large majority of all organic remains, 

but at some horizons and in a few localities, land plants 

characteristic of Pennsylvanian types have been found 

(fig. E24). Continental fossils recorded from the Manakacha of Grand Canyon to date include the conifer Walchia and some indeterminate ferns and plant stems, preserved in red-brown shaly mudstone. They are reported 

from Thunder River Trail, Bass Trail, and Parashant Canyon (table II).

• In the Wescogame Formation, as in the Manakacha, 

land plants are sparse. A few have been found in redbrown shaly mudstones near, the top. At Iceberg Canyon 

they occur associated with ripple marks in the upper part 

of the formation. From strata near the base of a red sandyshale slope near the Hermit Trail, which probably 

represents the top of the Wescogame but may be the basal 

slope member of the Esplanade, plant remains are recorded

by Schuchert (1918, p. 357). The strata are described as 

"thin, flaggy beds with some sun-crack fillings and an 

abundance of rain prints of the mammillary kind." The 

plants are stated to be "midribs of either ferns or 

cycadofilices." No other fossil plants are known from the 

Wescogame or Esplanade. Perhaps a strongly oxidizing environment, as suggested by the red beds in which they are 

preserved, explains their general scarcity in mudstones of 

the formation.

The Esplanade Sandstone contains plant stems, leaves, 

and other fragments at numerous localities, both in the 

shaly basal slope unit and in muddy beds and lenses within 

the main cliff unit above. They have been recorded from 

the Kaibab Trail, north, Topocoba Trail, S B Canyon, 

Grand Gulch Mine, and Hidden Canyon sections of Grand 

Canyon (table E3).

Land plants in shaly siltstones and mudstones of the 

Supai Group commonly are associated with both sedimen-
DISTRIBUTION AND AGE OF FAUNA AND FLORA 99

tary and organic structures of types that strongly suggest a 

continental environment of deposition. Shrinkage cracks 

and molds, rain pits, and cuspate ripple marks occur together with plant impressions at some localities; wormlike 

tubes or borings are recorded with them at numerous 

places.

The algal form known as Rivularites is moderately 

common in the Supai. It is considered to represent colonies 

of blue-green algae (Cyanophyceae) forming somewhat 

flexible carpets that floated or pulsated in water (White, 

1929, p. 43). This type of algae is believed by White to 

have lived in streams and "was adapted to survive occaA

FIGURE E22.—Trackways of vertebrate animals in fine-grained sandstone of Wescogame Formation. A, Set of poorly preserved tracks 

made by quadruped; surface of unoriented sandstone slab, Parashant 

Canyon. 8, Tracks of short-legged quadruped on 25°-slope of foreset 

bed in sandstone of the Wescogame, near Kaibab Trail, south. Toe 

marks point uphill; heel marks in each overlapping print show sand 

squeezed outward. Photograph by National Park Service. B
100 THE SUPAI GROUP OF GRAND CANYON

FIGURE E23.—Tracks (A, B) of vertebrate animal in the Esplanade Sandstone at Hidden Canyon in western Grand Canyon, Ariz.

EXPLANATION 

W Walchia sp. 

F Ferns 

R Rivularites 

P Plant stem

FIGURE E24.—Localities of continental flora in the Manakacha Formation, Grand Canyon region, Arizona.

sional periods of exposure to the air and drying." 

Rivularites is recorded from nine localities in Grand Canyon and from all formations of the Supai Group (table E3). 

It is a smaller form than that called Rivularites permiensis 

in the overlying Hermit Shale, according to White (1929, 

p. 43). Associated with Rivularites at three places in the 

Esplanade and at one each in the Watahomigi and 

Manakacha, were wormlike tubes or borings of a type 

described by White (1929, p. 115) from the Hermit Shale 

and named Scoyenia gracilis.

Although the land plants of the Supai Group, largely 

because of their fragmentary nature and poor preservation, furnish no precise information on the ages of various 

stratigraphic units, they indicate times and places of sea 

withdrawal. They establish the concept that broad fluctuations in marine-continental environments controlled 

deposition of the Supai Group. For many lithologic units 

in the Supai as with the Hermit Shale, the land plants establish the probable existence of wide flood plains developed during times of regressing seas and the likelihood of 

semiarid to arid climates.

BIOCLASTIC DEBRIS OF THE 

WATAHOMIGI FORMATION

An analysis of the bioclastic debris as represented in thin 

sections of the Watahomigi Formation illustrates a number 

of significant features relative to distribution of marine life 

and tends to confirm conclusions regarding paleogeography as described in chapter D. The principal faunal 

groups recognized in the bioclastic sediment of the formation are pelmatozoans (largely crinoids), small foraminifers, bryozoans, and bivalves (brachiopods and pelecypods, undifferentiated). The relative abundance of these 

groups in each of the three principal parts of the formation—slope at base, cliff in middle, slope at top—is shown 

in figures E25-E28. In comparing faunal distributions, it 

must be realized that (1) the lower two groups are of Morrowan age, the upper of Atokan age, and (2) the middle 

cliff is largely carbonate rock and therefore is especially 

favorable to a marine fauna, whereas the upper and lower 

slopes contain much mudstone and a correspondingly 

smaller amount of limestone.

Pelmatozoans are almost entirely restricted to the western half or seaward part of the Grand Canyon embayment, 

where they are widespread and common as shown in figure 

E25. The main exception in the east is at Hermit Trail 

where they are numerous in the upper slope of Atokan age. 

Small foraminifers make a distribution pattern (fig. E26) 

much like that of the pelmatozoans although the two mostly are not associated. In the western half of Grand Canyon 

foraminifers are numerous to abundant in many sections, 

but they are largely lacking farther east. The occurrence of 

these animals in the upper part of the formation at
DISTRIBUTION AND AGE OF FAUNA AND FLORA 101

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(30b Hidden Canyon Iceberg Canyon(31)

i i

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3

o

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2rodlike and Spherical 
102 THE SUPAI GROUP OF GRAND CANYON

EXPLANATION 

Percent of 

thin sections Abundance

0 O None

1-25 P Present

26-50 N Numerous

51-75 C Common

76-100 A Abundant

FIGURE E25.—Distribution of bioclastic debris containing pelmatozoans, Watahomigi Formation, Grand Canyon region, Arizona: A, lower slope

unit; 6, middle cliff unit; C, upper slope unit.

Thunder River, Grandview, and Bunker Trails (fig. D4) in 

eastern Grand Canyon may be because at the time of 

deposition (Atokan), the seaway at Grand Canyon connected with the Paradox basin farther east.

The Watahomigi Formation, especially in the middle 

cliff unit that is largely carbonate rock, contains the debris 

of bryozoans (fig. E27) and of bivalves, either brachiopods 

or pelecypods (fig. E28). Some large concentrations of 

these skeletal materials occur in the limestones.

BIOCLASTIC DEBRIS OF THE 

MANAKACHA FORMATION

Carbonate rocks of the Manakacha Formation include a 

considerable amount of bioclastic debris in sections widely 

scattered throughout the Grand Canyon. Numerous types 

of animals and plants are represented by skeletal fragments 

in this debris, the most common forms being pelmatozoans, 

bryozoans, foraminifers, bivalves (pelecypods and (or)

brachiopods), calcispherids, and Girvanella-type algae 

(fig. E29A-F).

The presence of bioclastic debris in many sections of 

eastern Grand Canyon, as well as farther west, suggests a 

marine passage across the Black Mesa sag in Atokan time, 

connecting the Cordilleran seaway in the west with waters 

of the Paradox basin to the northeast (fig. D4). This extension of the marine environment apparently caused a general expansion of sea life. The isopach map of Atokan 

rocks (fig. D4) indicates the pattern of seaways in Arizona 

at this time, and a comparison of this map with one of 

Morrowan rocks (fig. D3) shows the great change in configuration of landmasses that developed from Early to 

Middle Pennsylvanian time.

A comparison of distribution and abundance of the bioclastic debris, dominated by fragments of bivalves, is 

shown in figures E3CX4, B. Figure E3(X4 illustrates the lower 

part (cliff unit) and figure E30B the upper part (slope unit). 

Both parts show a wide distribution of bivalves in the 

Grand Canyon area, with eastern as well as western sections represented. The lower and older part shows greater
DISTRIBUTION AND AGE OF FAUNA AND FLORA 103

EXPLANATION

Percent of 

thin sections

0

1-25

26-50

51-75

76-100

Abundance 

O None 

P Present 

N Numerous 

C Common 

A Abundant

FIGURE E26.—Distribution of bioclastic debris containing foraminifers, Watahomigi Formation, Grand Canyon region, Arizona: A, lower slope

unit; 8, middle cliff unit; C, upper slope unit.

density than the upper and younger, possibly because the 

lower part is thicker and contains more carbonate rock, 

but, in general, the concept of a relatively stable environment in this area throughout Atokan time is supported.

BIOCLASTIC DEBRIS OF THE 

WESCOGAME FORMATION

Bioclastic debris constitutes a moderate proportion of 

the carbonate material in limestone of the Wescogame, but 

it is less common than in the underlying Manakacha. Skeletal grains consist mainly of foraminifers, and fragments of 

pelmatozoans (crinoids and sea urchins), bryozoans, and 

bivalves, including unidentifiable pelecypods and brachiopods. In general, bioclastic debris is far more abundant 

in the western than in the eastern part of the Grand Canyon region (fig. E31).

Isopach maps of the Wescogame (Virgilian time), constructed both for the Grand Canyon embayment (fig. Dll)

and for Arizona and adjacent states (fig. D7), show thickening of deposits westward toward the Cordilleran geosyncline and southeastward toward the Sonoran. The smallscale map (fig. D7) also shows a possible marine connection with the Paradox basin toward the northeast, although no conclusive proof of this connection (Black Mesa 

sag) is available from well-log data of the area.

Evidence from the distribution of bioclastic debris (fig. 

E31) suggests that the possible northeasterly marine connection did not exist in Virgilian time, as bryozoan and 

foraminiferal fragments have not been observed in eastern 

Grand Canyon sections, and both bivalve and pelmatozoan grains are uncommon in them. Thus, most of the 

skeletal fragments probably were derived from the Cordilleran seaway to the west as shown by the relative abundance of many animal forms in the western area and the 

absence of all but a few bivalve and crinoid fragments in 

the east. Possibly some of these eastern carbonate grains 

were derived from the southeast, but direct evidence is 

lacking.
104 THE SUPAI GROUP OF GRAND CANYON

EXPLANATION

Percent of 

thin sections

0

1-25

26-50

51-75

76-100

Abundance 

O None 

P Present 

N Numerous 

C Common 

A Abundant

FIGURE E27.—Distribution of bioclastic debris containing bryozoans, Watahomigi Formation, Grand Canyon region, Arizona: A, lower slope unit;

6, middle cliff unit; C, upper slope unit.

BIOCLASTIC DEBRIS OF THE 

ESPLANADE SANDSTONE 

AND PAKOON LIMESTONE

The environments of deposition in the Grand Canyon 

region during Early Permian (Wolfcampian) time, as represented by the Esplanade Sandstone and its western 

equivalent, the Pakoon Limestone, were different in 

several important respects from those of the older Supai 

formations in the same region. The area of sedimentation, 

instead of being a relatively restricted embayment along 

the eastern margin of the Cordilleran seaway and periodically connected with the main water bodies to the northeast and southeast, apparently was in Early Permian time 

part of a broad marine shelf extending across most of 

northern Arizona (fig. D8).

The Esplanade Sandstone, throughout most of the Grand 

Canyon area, is composed almost exclusively of quartz 

sand, whereas its western equivalent, the Pakoon Limestone, is a sequence of dominantly carbonate rock. The

lateral change from one rock type to the other is abrupt, 

and is accomplished by intertonguing within a narrow 

belt. Thus, the Esplanade of eastern and central Grand 

Canyon seems to represent a water body of high energy 

where extensive cross-bedding developed, whereas the 

Pakoon to the west had a relatively quiet-water environment in which a large and varied fauna, including sessile 

forms such as corals and bryozoans, lived.

Examination of bioclastic debris in thin sections from 

throughout the region (fig. E32), shows that a limited 

amount of skeletal material of various types is included 

nearly everywhere, but that the amount of bioclasts increases greatly toward the western area of carbonate deposition (Pakoon). Further, coral and bryozoan fragments 

are nearly restricted to the western area where they presumably lived, whereas grains derived from foraminifers, 

crinoids, echinoids, brachiopods, and others are numerous 

to common in areas far removed, to the east, in presumably 

inhospitable sandy environments.

How far various bioclasts were transported cannot 

be determined from available information, but the broad 

distribution and the progressively farther northeastward
DISTRIBUTION AND AGE OF FAUNA AND FLORA 105

EXPLANATION 

V Brachiopod and (or) pelecypod fragments

FIGURE E28.—Distribution of bivalves in bioclastic limestone, Watahomigi Formation, Grand Canyon region, Arizona: A, lower slope unit; 6, middle cliff unit; C, upper slope unit.

extension of bivalve, foraminifer, and pelmatozoan skeletons suggest that at least some of these skeletal remains 

may have been locally derived, rather than transported 

one hundred or more miles from the western (Pakoon) 

localities.

AGE OF THE SUPAI GROUP

The formations of the Supai Group are difficult to date 

precisely because of the general scarcity or lack of fossils in 

most parts of the area and because a majority of those 

fossils recorded either are long-ranging or their zonal distribution is not well known. Nevertheless, systematic collecting during the past 20 years has gradually assembled 

enough material to establish that the general age range extends from Morrowan into Wolfcampian time with, however, numerous hiatuses included, some of them probably 

of considerable duration.

The most important fossils in the determination of age in 

the Supai Group are fusulinids and brachiopods—the fusulinids showing a surprisingly wide distribution throughout

the Grand Canyon region at certain horizons. Brachiopods 

are restricted to the central and western parts of the region 

and mostly to the lower half of the Supai Group. Small 

nonfusulinid foraminifers have furnished information on 

some problems, although, in general, their distribution 

seems to be more facies-controlled than time-controlled. 

Corals have contributed some stratigraphic data in the 

dominantly carbonate-rock sections of westernmost Grand 

Canyon.

AGE OF THE WATAHOMIGI 

FORMATION

The Watahomigi Formation is believed to be largely of 

Morrowan age, but probably includes strata of Atokan age 

in the upper one-third. Several genera of brachiopods from 

limestone ledges in the lowermost slope of the formation 

help to establish the age of those beds. The diagnostic 

brachiopods are Punctospirifer transversus and Raticulariina campestris which, according to Mackenzie Gordon,
Q - § 

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53 o
DISTRIBUTION AND AGE OF FAUNA AND FLORA 107

EXPLANATION 

V Brachiopod and (or) pelecypod fragments

FIGURE E30.—Distribution of bivalve fragments in bioclastic limestones of the Manakacha Formation, Grand Canyon region, Arizona: A, cliff

unit; 8, slope unit.

Jr. (written commun., 1972) are restricted to Chesterian 

(Late Mississippian) and Morrowan time, and Derbyia sp., 

representing a genus that does not occur below the Pennsylvanian. Thus, an early Morrowan age is indicated for 

the lower part of the Watahomigi.

In the relatively massive limestone cliff unit that occurs 

in the middle part of the formation, Anthracospirifer occiduus, considered a "Lower Pennsylvanian indicator" 

(Dunbar and Condra, 1932, p. 325), occurs in abundance 

at numerous places in western Grand Canyon. Also in the 

middle part of the formation and commonly associated 

with A. occiduus is Linoproductus nodosus, found at eight 

localities in northwestern Arizona. This species is a very 

important time indicator for, according to Mackenzie Gordon, Jr. (written commun., 1974), it is restricted to the uppermost part of the Morrowan in other parts of the United 

States. It apparently delineates within narrow age limits 

this part of the Watahomigi.

Further evidence of age is furnished in the lower part of 

the formation by a microfacies including the small foraminifers Asteroarchaediscus sp., Neoarchaediscus parvus, 

and N. incertus. These fossils occur at several localities and 

suggest a Morrowan-Atokan age, according to Bernard 

Mamet (written commun., 1972).

In the upper one-third of the Watahomigi, strata 

probably are of Atokan age as indicated both by the stratigraphic position of the Linoproductus nodosus Zone which 

indicates the youngest Morrowan age rocks, and by evidence of a widespread erosion surface marked by a conglomerate bed at numerous localities in central Grand Canyon. This conglomerate occurs near the base of the slope 

unit that forms the upper third of the formation (fig. J2). 

Principal faunal evidence of a probable Atokan age for 

these strata is the presence near Kaibab Trail, north, and

on Grandview Trail of the fusulinid genera Fusulinella and 

Pseudostaffella, both of which have age ranges extending 

from Atokan into the Des Moinesian.

AGE OF THE MANAKACHA 

FORMATION

All or most of the Manakacha, as well as the upper third 

of the Watahomigi Formation, is believed to be of Atokan 

age both because of a position above the Linoproductus 

nodosus Zone and because of certain distinctive fusulinids 

that are also well represented in dated sections to the west 

and northwest of the Grand Canyon area (tables E4, D4). 

Probably the most diagnostic fusulinid for the Atokan age 

of these rocks is Profusulinella. The "Profusulinella fauna" 

of the Great Basin is given an Atokan age by Steele (1959, 

p. 37). The "zone of Profusulinella" is described (Welsh, 

1959, p. 30) "as geographically widespread" and a key to 

stratigraphic study in the Great Basin region. It is listed as 

being of "Atokan and Morrowan Ages" by Welsh (1959, 

table 2).

In the Grand Canyon area, Profusulinella sp. is found in 

the middle of the Manakacha Formation at Pigeon Wash 

(fig. Ell). It is reported by Douglass (1974) from three localities in southern Nevada, and by Steele (1959, p. 37) 

from the Beaver Dam Mountains, Utah, and at Frenchman 

Mountain, Nevada, to the north and west, respectively. 

Other fusulinids in Grand Canyon sections that are considered to be Atokan and occupy stratigraphic positions 

between Linoproductus nodosus and Profusulinella sp. are 

Fusulinella sp. and Pseudostaffella sp., commonly found 

together, and Eoschubertella sp. In both the Beaver Dam
108 THE SUPAI GROUP OF GRAND CANYON

EXPLANATION 

Percent of 

thin sections Abundance

0 0 None

1-25 P Present

26-50 N Numerous

51-75 C Common

76-100 A Abundant

FIGURE E31.—Relative abundance of various marine fossils in bioclastic debris, Wescogame Formation, Grand Canyon region, Arizona: A, foraminifera; B, pelmatozoan plates and spines; C, bryozoans; and D, bivalves (pelecypods and brachiopods).

Mountains, Utah, and the Frenchman Mountain, Nevada, 

Fusulinella sp. is associated with Profusulinella sp. (Steele, 

1959) and Fusulinella is shown by Brill (1963, fig. 9) in 

Atokan rocks of the Beaver Dam Mountains and by 

Douglass (1974) from three southern Nevada localities 

(table D4).

Eoschubertella sp., generally considered as of AtokanDes Moinesian age, is recorded from six localities in western Grand Canyon (figs. Ell, ElO). This genus is listed 

from North Virgin Mountains, Nevada, and from Pakoon 

Ridge, Arizona, by Welsh (1959, p. A12) who lists it as 

being of Des Moinesian age. In those places it is shown associated with or above Wedekindellina sp. and Fusulina

sp. so it may be a younger species than that from Grand 

Canyon. Eoschubertella sp. is recorded from Arrow Canyon and Mountain Spring Pass, Nevada, by Douglass 

(table D4).

The erosional surface at the top of the Manakacha Formation may represent a stratigraphic break representing 

both Des Moinesian and Missourian ages. No fusulinids of 

Des Moinesian or Missourian age have been found in the 

Grand Canyon area though they are reported from both 

south and west of the Canyon (table E4). To the south both 

Fusulina (probably Beedeina) and Wedekindellina were 

reported from East Verde River, Kohls Ranch, and Black 

River (Brew, 1965), and to the west one or both were re-
DISTRIBUTION AND AGE OF FAUNA AND FLORA 109

EXPLANATION 

Percent of

thin sections Abundance 

0 None 

P Present 

N Numerous 

C Common 

A Abundant

FIGURE E32.—Relative abundance of various marine fossils in bioclastic debris, Esplanade Sandstone and Pakoon Limestone, Grand Canyon 

region, Arizona: A, foraminifera, including fusulinids; 6, pelmatozoan plates and spines; C, bryozoans; D, bivalves (pelecypods and (or) brachiopods); and E, corals.

ported from Frenchman Mountain (Welsh, 1959; Steele, AGE OF THE WESCOGAME

1959), Pakoon Ridge (McNair, 1951; Welsh, 1959), and r/^n\ A A TI/^M

Virgin Mountains (Welsh, 1959). Triticites sp. of Missou- lOKMA I ION

rian age was reported from the south of Big Spring and at The Wescogame Formation is separated from the ManaCarrizo Creek (Brew, 1965) and from the west at French- kacha Formation by a widespread surface of erosion, conman Mountain (Steele, 1959). taining channels that in some places are 30 ft or more deep,
TABLE E4.—Fusulinids of the Supai Group and Pakoon Limestone1 in Grand Canyon area compared with those reported from areas to the northwe

Northwest of Grand Canyon

Age

Wolfcampian

Virgilian

Missourian

)es Moinesian

Atokan

Morrowan

Beaver Dam

Mountains,

Utah

OJ

£

Ful

Pro

!

Ful

Ful

Frenchman

Mountain,

Nev.

c^ 

I

Sew

Wed

OJ

Psc

Sew

Scb

Trt

Trt

Ful

Pro

Virgin

Moun

tains,

Nev.

cr< 

_c

1

Fus

Wed

Eos

Pst

Pakoon

Rdge,

Anz.

1

Trt

Eos

Fus

Wed

Eos

Pst2

vO

S

Trt

Grand Canyon area

measured section (No.)

(this paper

Iceberg Canyon(

Psc

Sew

Scb

Trt

Eos

-Q

Hidden Canyon

Psc

Sew

Scb

Trt

Mon

Trt 

Oza

Eos

Ful

Pigeon Wash (28

Psc

Sew

Scb

Eos

Ful

Pro

Snap Canyon(27

Sew

Scb

Trt

Eos

Guano Cave(26)

Scb

0

U

00

c: 

Q. 

c

i

Scb

Eos

s

Parashant Canyor

Eos

?S

Whitmore Wash

Trt

C 

O

c

Blue Mountain C

Scb

S BCanyon (17)

Scb

91

1

X

Ful

CO

Kaibab Trail, nort

Ful

Pst

vO

Grandview Trail

Ful

Pst

3 

U_

8

Ful

Pst

Fossil Creek

Fus

W

No fusulinids of this age.

1 Pakoon Limestone of McNair (1951); Esplanade Sandstone equivalent in western Grand Canyon. 

2 Recorded as Atokan-Morrowan age and Morrowan (?).

ABBREVIATIONS

Ful Fusulinella sp. 

Pro Profusulinella sp. 

Sew Schwagerina sp. 

Psc Pseudoschwagerina sp. 

Scb Schubertella sp. 

Trt Triticites sp. 

Wed Wedekindellina sp.

Eos 

Mon 

Oza 

Pst 

Dun 

Fus

Eoschubertella sp. 

Monodiexodina sp. 

Ozawainella sp. 

Pseudostaffella sp. 

Dunbahnella sp. 

Fusulina sp.
DISTRIBUTION AND AGE OF FAUNA AND FLORA 111

and covered in many places with a blanket of conglomerate. The magnitude of the hiatus represented by this 

erosion surface is not known but, as mentioned already, 

probably includes at least Des Moinesian and Missourian 

equivalents. The sea apparently withdrew completely to 

allow the widespread dissection cited and to permit a complete change of fauna.

The earliest fusulinids found in the Wescogame Formation are Triticites ssp. of probable Virgilian age from near 

the base in the Hidden Canyon section (fig. E13). Specimens of the genus Ozawainella are common higher in the 

section at Hidden Canyon.

Two coral species from the upper part of the Wescogame 

Formation at Hidden Canyon have been examined by 

W. J. Sando. These corals were determined as Syringopora 

multattenuata McChesney and Caninia sp., considered 

compatible with a Late Pennsylvanian age.

AGE OF THE PAKOON 

LIMESTONE

The Pakoon Limestone (McNair, 1951, p. 524) is considered to be the lateral equivalent of the lower part of 

the Esplanade Sandstone. The Pakoon occurs in western 

Grand Canyon and intertongues eastward into the Esplanade. McNair (1951) determined the age of the Pakoon as 

Wolfcampian on the basis of characteristic fusulinids from 

the type locality at Pakoon Ridge in northwestern Arizona. Faunal evidence from the present study corroborates 

this assignment.

Because the Pakoon or equivalent Esplanade is separated 

from the underlying Wescogame Formation by an erosion 

surface and a blanket of conglomerate throughout the 

Grand Canyon region, a significant hiatus seems to have 

preceded its deposition. As the Wescogame is believed to 

be of Virgilian age, the time represented by the unconformity probably includes the last part of the Virgilian, the early 

part of the Wolfcampian, or both.

Most important faunal evidence of Wolfcampian age is 

the presence of Schwagerina sp. at Hidden Canyon, Pigeon 

Wash, Snap Canyon, and Iceberg Canyon (fig. E15) and of 

Pseudoschwagerina sp. at all of those localities except 

Snap Canyon. Other fusulinids, common in rocks of Wolfcampian age, and associated with the preceding are Triticites sp. and Schubertella sp.

Further evidence of age is furnished by small (nonfusulinid) foraminifers among which Calcivertella sp., Spandelinoidsl sp., and Geinitzina sp. were recognized by L. G. 

Henbest (written commun., 1964) from the Iceberg Canyon collections. These genera are believed to be characteristic of Late Pennsylvanian and Early Permian time according to Henbest.

Corals, which are abundant and varied in the Pakoon 

Limestone (fig. E17), give supporting evidence for the 

Wolfcampian age of this formation. Those "from the middle and basal part of the upper cliff member are firmly 

dated as Early Permian" according to W. J. Sando (written 

commun., 1964), and they are similar to the Lower Permian faunas from the area of Ely, Nev.

An upper limit for the age assignment of Pakoon Limestone and Esplanade Sandstone is furnished in eastern 

Grand Canyon by the flora near the base of the overlying 

Hermit Shale. The fossil plants in this formation were collected extensively in eastern Grand Canyon along the Hermit and Kaibab Trails and have been analyzed with respect 

to age by White (1929, p. 28-40). A conclusion that the 

Hermit Shale "belongs well up in the upper Rothliegende— 

the upper part of the Lower Permian" was reached by 

White (1929, p. 40). Characteristic plants of the Hermit 

have subsequently been found far to the west at Parashant 

Canyon (McKee, 1937, p. 341); therefore, the Esplanade 

Sandstone below the Hermit must be restricted to an early 

part of the Permian throughout much of the region.

A Leonardian age for the Hermit Shale is further suggested by a specimen of the species, Callipteris arizonae, 

found in the Hermit that has also been collected by Humble 

Oil Co. geologists from the Bone Spring Limestone, of 

Leonardian age in southeastern New Mexico (McKee and 

Oriel, and others, 1967, p. 215).

AGE OF THE ESPLANADE 

SANDSTONE

Direct evidence, based on fossils, for the age of the 

Esplanade Sandstone, is lacking. Because its lower part intertongues with the Pakoon Limestone of Wolfcampian 

age to the west, however, the Esplanade must be, at least in 

part, of this age. Whether the upper part, which changes to 

a fine-grained detrital facies and extends westward above 

the Pakoon, is also Wolfcampian is not known. An early 

Leonardian age has been suggested for it by Walter Pierce 

(written commun., 1976) on the basis of a fusulinid that he 

collected from the upper part of the Pakoon at Grand 

Gulch. The specimen was identified as Schwagerina linearis and interpreted as "Upper Wolfcampian" by George J. 

Verville.

REFERENCES CITED

Baird, Donald, 1965, Footprints from the Cutler Formation, in Early 

Permian vertebrates from the Cutler Formation of the Placerville 

area, Colorado: U.S. Geological Survey Professional Paper 503-C, 

p. C47-C50.

Brew, D. C, 1965, Stratigraphy of the Naco Formation (Pennsylvanian) 

in central Arizona: Cornell University, Ph. D. thesis, 201 p.
112 THE SUPAI GROUP OF GRAND CANYON

Brill, K. G., Jr., 1963, Permo-Pennsylvanian stratigraphy of western Colorado Plateau and eastern Great Basin regions: Geological Society of 

America Bulletin, v. 74, p. 307-330.

Douglass, R. C., 1974, Fusulinids in the Basin and Range Province in 

California, Nevada, and Utah: Journal of Paleontology, v. 48, no. 4, 

p. 846-853.

Dunbar, C. O., and Condra, G. E., 1932, Brachiopoda of the Pennsylvanian system in Nebraska: Nebraska Geological Survey 2d ser. Bulletin 5, 377 p.

Gilmore, C. W., 1926, Fossil footprints from the Grand Canyon: Smithsonian Miscellaneous Collections, v. 77, no. 9, 41 p.

____1927, Fossil footprints from the Grand Canyon; second Contribution: Smithsonian Miscellaneous Collections, v. 80, no. 3, 78 p.

____1928, Fossil footprints from the Grand Canyon; third Contribution: Smithsonian Miscellaneous Collections, v. 80, no. 8,16 p.

Haubold, von Hartmut, and Katzung, Gerhard, 1975, Die position der

Autun/Saxon-Grenze (Unteres Perm) in Europa und Nordamerika:

Schriftenreihe fur Geologische Wissenshaften, Berlin, v. 3,

p. 87-138. 

Hitchcock, Edward, 1858, Ichnology of New England; A report on the

sandstone of the Connecticut Valley, especially its footmarks:

Boston, W. White, 220 p. 

Jardine, William, 1853, The ichnology of Annadale, or illustrations of

footmarks impressed on the New Red Sandstone of Corncockle

Muir: Edinburgh, 17p., 13pis. 

Lotze, F. 1928, Die Tambacher Sphaerodactylum-fahrten: Palaontologische Zeitschrift, v. 9, p. 170-175.

McKee, E. D. 1937, Researches on Paleozoic stratigraphy in western 

Grand Canyon: Carnegie Institution of Washington Year Book 36 

for 1936-1937, p. 332-345.

McKee, E. D., Oriel, S. S., and others, 1967, Paleotectonic investigations 

of the Permian System in the United States: U.S. Geological Survey 

Professional Paper 515, 271 p.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin 

v. 35, no. 3, p. 503-541.

Nopcsa, Franz, 1923, Die Familien der Reptilien: Geologic 2nd Palaeontologic Fortschrift. 1st, no. 2, 210 p.

Schuchert, Charles, 1918. On the Carboniferous of the Grand Canyon of 

Arizona: American Journal of Science, 4th ser., v. 45, no. 267, 

p. 347-361.

Steele, G., 1959, Stratigraphic interpretation of the Pennsylvanian-Permian Systems of the eastern Great Basin: Washington University, 

Ph.D. thesis, 294 p.

Vaughn, P. P., 1962, Vertebrates from the Halgaito tongue of the Cutler formation, Permian of San Juan County, Utah and Arizona: Journal of Paleontology, v. 36, p. 529-539.

____1964, Vertebrates from the Organ Rock Shale of the Cutler Group, 

Permian of Monument Valley and vicinity, Utah and Arizona: Journal of Paleontology, v. 38, no. 3, p. 567-583.

Welsh, H. E., 1959, Biostratigraphy of the Pennsylvanian and Permian 

System of southern Nevada: Utah University, Ph. D. thesis, p. 1-106, 

A-l-A-12.

White, David, 1929, Flora of the Hermit Shale, Grand Canyon, Arizona: 

Carnegie Institution of Washington Publication 405, 221 p.
THE SUPAI GROUP OF GRAND CANYON

BIOSTRATIGRAPHY OF THE 

WATAHOMIGI FORMATION

Chapter F 

By MACKENZIE GORDON JR.

Contents

Introduction .... ..........................

The Supai study ..... .......................

Occurrence of the fossils . .....................

Fossil megafauna . . ......................

Corals, conulariids, and bryozoans ..........

Brachiopods . . . . .........

Pelecypods ...........................

Rostroconchs ..........................

Gastropods ,,„,...............,,...,..

Cephalopods ...... ...................

Echinoderms. trilobites, and fish .............

Fauna of the lower slope unit . ..................

Fauna of the middle cliff unit . ..................

Fauna of the upper slope unit . ..... .....

Correlation with the type Morrowan and Atokan ....

Correlation with other western American formations . 

Correlation with standard European sections . 

Climate ....... ........,,,,.,

Paleogeographic considerations . . ........

References cited ..............................

Page

115

115

115

116

116

116

120

120

120

121

121

121

122

122

122

123

123

125

125

126

113
114 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURE F1. Correlation of Lower and lower Middle Pennsylvanian formations in the south-central

and southwestern United States ... : ......... 124

PLATES F1-F3. Brachiopods . . . ...........,...,,,....,,,....,,....,....,.,....,.......,.. 128

F4. Pelecypods and gastropods ................................................ 134

Tables

Page

TABLE F1. Megafauna of the Watahomigi Formation . ............................... 118

F2. Major life-habit groups of Watahomigi pelecypods ............................... 120
BIOSTRATIGRAPHY OF THE WATAHOMIGI FORMATION 115

INTRODUCTION

The Watahomigi Formation contains the largest and 

most varied invertebrate fauna of any of the formations of 

the Supai Group. More than 85 species of megafossils have 

been recognized in this fauna, including remains of corals, 

bryozoans, brachiopods, pelecypods, gastropods, echinoids, and trilobites. The fossils indicate a middle to late 

Morrowan (Early and Middle Pennsylvanian) age for the 

greater part of the formation. Foraminiferal evidence from 

the upper part, however, suggests that this part is early 

Atokan in age.

McKee (chapter C) has recognized three informal divisions of the Watahomigi Formation. A lower slopeforming unit is succeeded by a middle cliff-forming limestone unit, and this limestone by an upper slope-forming 

unit. The base of the upper unit is marked by a conglomerate bed of wide lateral extent, which delineates the base of 

the Atokan part of the formation.

The Watahomigi Formation is the lowest division of the 

Supai Group and rests unconformably upon an erosion 

surface of highly resistant chert beds and softer limestone 

beds, probably representing the Horseshoe Mesa Member 

of the Redwall Limestone (McKee, 1963, p. C21). In Havasu Canyon, the cherts contain fossils of early to middle 

Meramecian (early Late Mississippian) age, including the 

brachiopods Orthotetes kaskaskiensis (McChesney), Torynifer setiger (Hall), and Anthmcospirifer bifurcatus (Hall). 

This faunule can be no younger than St. Louis (Late Mississippian) in age. The presence of these resistant beds overlain and surrounded by the basal beds of the Watahomigi 

Formation does not necessarily imply a total lack of 

deposition within the time span represented by the 

unconformity. On the contrary, a 6.5-ft limestone bed at 

Bright Angel Trail has been reported to contain fossils of 

Chesterian age (McKee and Gutschick, 1969, p. 74). More 

recently, large buried valleys cutting the Redwall Limestone in western Grand Canyon have been found to contain upper Chesterian strata, as described by Billingsley 

and McKee in chapter G. This would indicate that some 

deposition took place in northern Arizona during the Late 

Mississippian, and that these deposits were removed by 

erosion over large areas during the latest Mississippian and 

Early Pennsylvanian.

THE SUPAI STUDY

The study of the megafossils of the Supai Group has occupied several paleontologists intermittently over a period 

of approximately 15 years, as the fossil collections 

accumulated. Corals were studied by W. J. Sando, brachiopods by R. E. Grant, pelecypods by John Pojeta, Jr., gastropods by E. L. Yochelson, and fish remains by D. H.

Dunkle. In addition to the megafauna, fusulinids were 

studied by R. C. Douglass and smaller foraminifera and 

algae by Bernard Mamet. The writer came into the study in 

1973 (after R. E. Grant took over administrative duties 

with the National Museum of Natural History) and was 

asked to complete the work on the Supai material. Part of 

the collections had been dissipated and turned over by 

McKee to two northern Arizona museums. Wishing to see 

all of the collections together, the writer asked that they be 

reassembled and McKee very kindly complied. Opportunity was thus provided to study the fauna as a whole and 

additional fossil preparation also yielded a number of previously unrecorded species. Publication of the Sutherland 

and Harlow (1973) study of Pennsylvanian brachiopods 

and biostratigraphy in the southern Sangre de Cristo 

Mountains, New Mexico, provided names for part of the 

brachiopod fauna. Conferences with T. W. Henry, who 

was studying the brachiopods of the Morrowan Provincial 

Series in Arkansas and Oklahoma, also were helpful in 

providing a basis for correlating the Watahomigi beds with 

the type Morrowan section. The Supai study has been time 

consuming, but has yielded considerable information and 

a better understanding of the Pennsylvanian history of the 

Grand Canyon region.

OCCURRENCE OF 

THE FOSSILS

Most of the Watahomigi Formation collections are 

from rather coarse gray limestone, much of it a granular 

organic detritus. Fossils are scattered through the matrix, 

locally in considerable numbers. Some fossils occur in 

rather resistant limestone or in chert, and a few in 

calcareous sandstone beds. None seem to have come from 

the red beds. Despite the relatively restricted types of 

lithology of the fossiliferous strata, considerable variation 

exists between individual beds and it often is possible to 

recognize the matrix as coming from a certain bed or 

geographic locality. For instance, USGS collection 

25127-PC, from 12 ft above the base of the formation in 

National Canyon, is from a reddish-brown conglomeratic 

limonitic sandstone not seen in other sections. USGS collection 27031-PC, from 10 ft above the base, near Bridge 

Canyon, combines a light-gray granular limestone with 

small pellets of limonitic material; this also seems distinctive to the locality.

Fossils from the east side of Toroweap Valley include 

large Orbiculoidea and myalinid pelecypods in a matrix of 

near-white to dirty gray or dark brownish-gray sandstone. 

Specimens from the cliff-forming middle part of the formation are generally preserved in gray limestone and the collections are not so easily distinguished one from the other 

by lithology.
116 THE SUPAI GROUP OF GRAND CANYON

The preservation of the fossils ranges from good to 

poor, but the poor end of the spectrum is much more in 

evidence. Well-preserved specimens are a great rarity and 

very few fossils are complete, or even nearly so. Much of 

this is due to the crumbly nature of the coarse granular 

limestone and the fact that most of the fossils are calcareous, rather than silicified.

FOSSIL MEGAFAUNA

Table Fl shows the distribution of the Watahomigi 

megafauna. The sections are listed in geographic succession from west to east and the fossils are arranged systematically. The occurrence of each species is recorded as to 

distance above the base of the formation in each measured 

section. The abundance of each species in each collection is 

indicated by the following symbols in the table:

A—Abundant (more than 50 specimens). 

C—Common (15-20 specimens). 

X—Well-represented (4-14 specimens). 

R—Rare (1-3 specimens).

Such a key is only approximate, owing to such factors as 

personal bias in collecting, vicissitudes of preservation, 

and the fact that it was made not by the collectors but by 

those making the identifications. Nevertheless, it provides 

a far better picture of the distribution of the fauna than 

does merely recording the occurrence of species at a given 

locality.

The following discussion of the fossil megafauna is arranged according to the major categories shown in table Fl. 

As a large proportion of the species are not yet described 

and as some of the specimens are too poorly preserved for 

specific identification, it is hoped that the following discussion of criteria for identification and remarks as to the 

distribution will be helpful.

Corals, conulariids, and bryozoans

No solitary corals are present in our collections. Two 

small fragments, each assignable to a different genus of 

colonial corals, constitute the entire coelenterate record 

from the Watahomigi. These occur in the lower slope unit 

of the formation.

A poorly preserved conulariid fragment, not identifiable 

as to genus, was found in each of two collections in the 

lower slope unit of the formation.

Remains of bryozoans are nowhere abundant but are 

present in 11 collections, mainly in the eastern half of the 

outcrop belt, as indicated in table Fl. The most common of

these are small rhomboporoid bryozoans, present in 6 

collections; in one of these they are fairly numerous. The 

next most common form is a thin stenoporoid bryozoan incrusted on brachiopods such as Anthracospirifer, Composite, or Orthotetes. A single massive stenoporoid was collected in Parashant Canyon, in the lower part of the formation. A bifoliate fistuliporoid and an incrusting fistuliporoid 

are rare at each of two localities in the lower slope part of 

the formation. A ramose treptostomatous bryozoan, two to 

three times the diameter of the rhomboporoid, is present in 

five collections, including the most westerly occurrence of a 

bryozoan at Hidden Canyon. Fenestrate bryozoans probably are assignable to Fenestella and to Polypora, but are 

not common. A poorly preserved ribbonlike bryozoan fragment, having linear grooves along which the zooecia occur, 

is referred with question to Cystodictya.

Brachiopods

Among the inarticulate brachiopods, a single incomplete 

valve of Lingula is present. Although resembling L. carbonaria Swallow in size and shape, it is not complete 

enough to identify positively. Two species of Orbiculoidea 

also occur. One of these, identified as O. meekana (Whitfield) (pi. Fl, figs. 1, 2) is common on the east side of Toroweap Valley at a stratigraphic level regarded as early Atokan in age. It is a large subcircular form having an eccentric 

apex, mature specimens ranging in length from 22 to 

26 mm. The other, from Snap Canyon, resembles O. missouriensis (Shumard) and is based upon a single incomplete 

brachial valve. The Entletacea are represented by a single 

species, Schizophoria altirostris (Mather), (pi. Fl, figs. 3-5), 

at scattered localities in the lower part of the formation.

Three species of orthotetaceans are recognized. Orthotetes sp. A (pi. Fl, figs. 6, 7) has a sharp-pointed umbo, a 

moderately low interarea at an angle of about 45° to the 

plane of the pedicle valve, and the hinge line slightly shorter 

than the greatest width; the surface is parvicostellate, consisting of intercalating costellae of which 9 to 11 occur in the 

space of 5 mm. The median septum forks narrowly near the 

umbo, enclosing a narrow matrix-filled space between two 

barely diverging dental plates, the delthyrium being very 

narrow. The brachial valve has its greatest convexity near 

mid-valve and is somewhat flattened near the umbo.

Derbyia sp. A (pi. Fl, figs. 8-10) has a low blunt umbo, 

the interarea at an angle of 70° to the plane of the pedicle 

valve. The brachial valve has its greatest convexity considerably posterior to mid-valve. The sculpture is parvicostellate but commonly approaches multicostellate, 13 to 16 

costellae occurring in the space of 5 mm. The median septum does not split and within the umbo the palintrope is 

filled with secondary shell deposit. Derbyia sp. A and Orthotetes sp. A have overlapping stratigraphic ranges in the 

lower and middle parts of the formation.
BIOSTRATIGRAPHY OF THE WATAHOMIGI FORMATION 117

A single large incomplete pedicle valve appears identical 

to material from the Amsden Formation of Wyoming identified as Derbyia cf. D. robusta (Hall) by Gordon (1975, 

p. D31).

Productacea are represented by only five genera in the 

Watahomigi fauna and, except for Linoproductus, are 

rare. They include characteristic middle and upper Morrowan species. Linoproductus sp. A, a precursor of L. 

nodosus in Arkansas, occurs in the lower middle part of 

the Watahomigi Formation. It is recognized by a double 

row of alternating spines ornamenting the middle zone of 

the pedicle valve, beginning near the umbo. An illustration 

of a well-preserved specimen of this species, from the 

Brentwood Limestone Member of the Bloyd Shale in Arkansas, appeared in a paper by Henry and Sutherland 

(1977, pi. 2, fig. 5). Linoproductus pumilis Sutherland and 

Harlow (pi. Fl, figs. 20-22) occurs in the lower and middle 

parts of the Watahomigi and the small Buxtonial sp. 

(pi. Fl, figs. 11, 17-19) comes from the lower part of the 

middle cliff unit. Buxtonia sp. (pi. Fl, figs. 23-25), Pulchratial picuris Sutherland and Harlow (pi. Fl, 

figs. 26-32), and Linoproductus nodosus (Newberry), 

shown in plate Fl, figures 12-16, occur in the upper part of 

the middle cliff unit. P.? picuris also occurs in the lower 

middle part.

Rhynchonellaceans occur at three localities in the eastern part of the outcrop belt. At two of them, a species resembling Cupularostrum is rare and represented by poorly 

preserved specimens. Near the base of the formation, in 

National Canyon, a tiny rhynchonellacean (pi. F2, 

figs. 7-16) that superficially resembles the stenoscismatacean genus Coledium, but has a rhynochonellacean 

interior, occurs abundantly. R. E. Grant, who initially examined this material, believes it may represent an 

undescribed genus.

Athyridaceans, all of them belonging in the genus Composita, are common to abundant in the Watahomigi and 

three species have been recognized. Small- to medium-size, 

moderately narrow to moderately broad shells, having the 

greatest width at the middle of the valve and the anterior 

commisure exhibiting a broad shallow deflection, are referred to C. ovata Mather (pi. F2, figs. 17-31). Similar, but 

smaller, narrower, and more inflated shells are referred to 

C. gibbosa Mather (pi. F2, figs. 32-41). Subtriangular 

shells, having the greatest width well anterior to the middle 

of the valves are referred to C. subtilita (Hall), as shown in 

plate F3, figures 6, 7. A closely related, possibly conspecific, large transverse Composita occurs with it in the middle cliff unit in the Guano Cave section (pi. F3, figs. 1-5).

The cyrtiacean Crurithyris planiconvexa (Shumard) is 

shown on plate F2, figures 1-6; abundant in many Pennsylvanian formations, it is rare in the Watahomigi. Only three 

specimens are present in the collections studied, and these 

are from the upper slope (Atokan) part of the formation.

Four species of Anthracospirifer make up the rather

abundant spiriferacean population of this formation. The 

most common and widely distributed of these is A. tanoensis Sutherland and Harlow (pi. F3, figs. 17-19), which occurs throughout the Morrowan part of the formation and 

is present in the Atokan part as well. This is a moderately 

small species, normally having 3 costae in the sulcus and 9 

to 11 on each lateral slope. Some specimens have as many 

as 5 costae in the sulcus and some show a tendency for 1 or 

2 of the lateral costae to bifurcate. These more highly 

costate specimens are regarded as advanced forms of A. tanoensis approaching A. chavezae Sutherland and Harlow. 

At Bridge Canyon, in the basal part of the formation, is an 

Anthracospirifer having 3 costae in the sulcus and 8 rather 

broad costae on each lateral slope. This has been identified 

as A. cf. A. opimus (Hall) in this report, as it closely resembles Hall's Midcontinent Middle Pennsylvanian 

species. The possibility exists, however, that this form is 

merely a variant of A. tanoensis, which occurs at the same 

level in the formation elsewhere.

A. newberryi Sutherland and Harlow (pi. F3, figs. 20, 

21) has been recognized at a few localities, generally in 

association with A. tanoensis. This is an alate form having 

a low fold and sulcus, with 3 costae in the sulcus and as 

many as 15 simple costae on each lateral slope. A variant 

of this species, having the third and fourth costae on either 

side of the sulcus splitting toward the sulcus as in A. occiduus, was recorded at two localities.

A. occiduus Sadlick (pi. F3, figs. 8-16) occurs abundantly in the lower and middle parts of the formation in 

the vicinity of Guano Cave. Some variation is exhibited in 

these shells with regard to the splitting patterns of the 

lateral costae, but they include specimens that agree closely with the primary types from Idaho. This is the largest of 

the Watahomigi anthracospirifers.

Spiriferaceans were found in three measured sections, 

all of them in the lower half of the formation, in several 

canyons adjacent one to the other. The most common 

species is Punctospirifer transversus (McChesney), shown 

in plate F3, figures 22-24. Complete pedicle valves have as 

many as 15 costae on each lateral slope. At first it was 

thought that two punctospirifers might be present: those in 

limestone beds generally having 11 to 15 costae on each 

lateral slope, and those in shale layers commonly having 8 

to 11 costae in the same area (a number typical of P. morrowensis Sutherland and Harlow). However, a few 

specimens in shale layers were found to have as many as 13 

costae on either lateral slope, so it is concluded that the 

punctospirifers belong in one variable species.

Two poorly preserved specimens from two localities 

were identified as IReticulariina gonionota (Meek). These 

have four to five plications at either side of the sulcus and 

although surface spines cannot be discerned clearly, local 

knobby surfaces suggest that worn spine bases are present.

Lastly, a small unidentifiable terebratuloid brachiopod 

(pi. F2, figs. 42-46) was found in the lower of two collections from National Canyon.
118 THE SUPAI GROUP OF GRAND CANYON

TABLE F1.—Megafauna of the Watahomigi Formation

[A, abundant (more than 50 specimens); C, common (15-50 specimens); X, well-represented (4-14 specimens); R, rare (1-3 specimens)]

Fauna

Corals:

Measured 

section

uses

Collection No.

Distance 

above base (ft)

Michelma sp.

Synngopora sp.

Conulanids:

Conularild, gen. & sp indet.

Bryozoans:

Fistuliporoid,

Fistuliporoid,

Trepostome,

Stenoporoid,

Stenoporoid,

incrustlngform

bifoliate form

ramose form

ncrustmgtorm

massive form

Fenestella sp.

Po/ypora sp.

Rhomboporo d, gen. & sp. indet.

Cystod/ctya? sp.

Brachiopods:

Lingula sp. indet.

Orbicu/o/dea cf. O missounens/s (Shumard)

meekana (Whitfield)

Schizophona altirostns 

(Mather)?

Orthotetes sp A

Derby/a sp. A

cf. D robusta (Hall)

Orthotetacean, gen. & sp. indet.

Pu/chrat/a?picur/s Sutherland 

and Harlow

f/exar/a?sp.

Buxfoma sp.

Lmoproductus nodosus 

(Newberry)

sp. A

pumilis Sutherland and 

Harlow

Productoid, gen. & sp. indet.

Rhynchonello d cf. Cupulo 

rostrum sp.

N. gen. aff. Anter/docus n. sp.

Composita g bbosa Mather

ovata Mather

subt/'/ita (Hall)

sp. indet.

Crurithyris planoconvexa 

(Shumard)

Anthracosp/nfer cf. A. opimus 

(Hall)

tanoens/s Sutherland and 

Harlow

newberryi Sutherland and 

Harlow

occ/duus (Sadhck)

Punctospint'er transversus 

(McChesney)

?Re(/cu/an/na gon/onota 

(Meek)

Dielasmid, gen. & sp. indet.

Pelecypods:

Nucu/opsis (Nuculanella) sp.

Palaeone//o? sp. indet.

Paleyoldia sp.

Phest/a sp.

Promy(//us sp.

Myalma (Myalina) sp. A

sp. B

Se/enimyal/na? sp.

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27

2
120 THE SUPAI GROUP OF GRAND CANYON

Pelecypods

Myalinids and, to a lesser extent, aviculopectenids, myophoriids, and permophorids are the dominant elements of 

the pelecypod fauna of the Watahomigi. Taxodont genera 

are rare: those recognized in the formation include Nuculopsis (Nuculanella) (pi. F4, figs. 2, 3), Palaeoneilol, 

Paleyoldia, and Phestia (pi. F4, figs. 1, 4), the whole group 

represented by only a few specimens. The mytilacean Promytilus (pi. F4, fig. 11) and pteriacean Leptodesma are 

likewise represented in our collections at few localities and 

generally by only one or two specimens at a locality.

The myalinids include five recognizable forms. Common in calcareous sandstone beds of the upper slope unit 

on the east side of Toroweap Valley is a strongly prosocline species, Myalina (Myalina) sp. A (pi. F4, figs. 9, 10). 

More common in limestone beds, particularly in Snap 

Canyon, is a more steeply inclined species, M. (Myalina) 

sp. B (pi. F4, fig. 12). In addition, a single specimen has the 

configuration of Selenimyalina. Septimyalina sp. A (pi. 

F4, figs. 7, 8), having an acutely subangular diagonal ridge 

extending from the umbo is abundant near the base of the 

formation in National Canyon. Owing in part to its preservation in fairly hard limonite, the plate covering the umbonal cavity can be seen in several of our specimens. Septimyalina sp. B (pi. F4, fig. 13) includes those forms apparently lacking an anterior lobe and having a rounded, 

rather than a subangular, diagonal ridge. Because of preservation in soft limestone that is easily weathered, no umbonal plate was visible, hence the identification of the second Septimyalina is somewhat tentative.

The Watahomigi Aviculopectenidae consist entirely of 

members of the genus Aviculopecten. The most common 

species, but nowhere represented by more than a few specimens, is A. gravidus Gordon and Pojeta (pi. F4, fig. 17), 

having a radially lirate right valve of low convexity and an 

inflated semiovate left valve ornamented by radial and 

concentric lirae that form a finely reticulate pattern. Aviculopecten sp. A, which occurs at several localities, is a 

typical aviculopectenid, represented exclusively by left 

valves that bear several ranks of radiating costae. A very 

similar form, from the Wescogame Formation, is shown in 

figure E14. A rare form, Aviculopecten sp. B (pi. F4, 

figs. 5, 6), known from a single left valve from each of two 

localities, has approximately 12 major costae, bearing 

short nodelike spines on one of the specimens. Completing 

the roster of aviculopectenids is a large fragment of a valve 

that bears radiating costae crossed by concentric striae and 

identified here as Aviculopectenl sp. indet.

The myophoriids include three species of Schizodus in 

the Watahomigi Formation. The largest of these and the 

only one identified with a previously described species is 

Schizodus amplus Meek and Worthen (pi. F4, figs. 20-22),

a rather inflated, suboval to subcircular species having a 

raised internal ridge in front of the posterior adductor muscle scar. Schizodus sp. A (pi. F4, fig. 19) is a shallow 

elongate form that reaches a length of 7 cm, but normally 

is smaller. Schizodus sp. B (pi. F4, fig. 18) is a similar 

elongate species having an exterior subangular ridge 

directed posteriorly from the umbo.

Associated with the myophoriids is a telliniform pelecypod, its surface ornamented by concentric lirae. This species bears a superficial resemblance to OriocrassateHa, to 

which it is referred with question. As the hinge and dentition have not been seen, no assurance exists that it is a 

crassatellacean.

Permophorus is fairly common, represented in the 

Watahomigi Formation at five localities by what seems to 

be the same rather short species (pi. F4, figs. 15, 16). Tentatively referred to Edmondia (pi. F4, fig. 14) is a specimen 

from the section south of Pica. American shells having this 

configuration are commonly referred to this genus, 

although they have a less excentric beak and a smoother 

shell than the British type species. Finally, a few shells and 

fragments of Wilkingia terminalis (Hall), shown on plate 

F4, figure 28, have been found at Hidden and Snap Canyons and in the Guano Cave section.

In table F2, the genera to which the Watahomigi pelecypods have been referred are arranged according to lifehabit. A similar arrangement of pelecypod genera from the 

Amsden Formation of Wyoming appeared in a report by 

Gordon and Pojeta (1975, p. E3).

TABLE F2.—Major life-habit groups of Watahomigi pelecypods

Infaunal libial 

palp deposit 

feeders

Nuculopsis (Nuculanella) 

Palaeoneilo 

Phestia 

Paleyolida

Attached 

suspension 

feeders

Promytilus 

Myalina (Myalina) 

Selenimyalina 

Septimyalina 

Leptodesma 

Aviculopecten

Infaunal burrowing 

suspension 

feeders

Schizodus 

OriocrassateHa 

Permophorus 

Wilkingia

Rostroconchs

The only rostroconch noted in the collections is a small 

incomplete Pseudoconocardium collected near the base of 

the formation in Separation Canyon.

Gastropods

The number of gastropod species recognized in the formation approximates the number of pelecypod species, but
BIOSTRATIGRAPHY OF THE WATAHOMIGI FORMATION 121

the gastropods are more restricted in stratigraphic range 

and geographic distribution and are represented by fewer 

specimens. Only three collections contain a significantly 

diverse gastropod fauna. These occur in Separation, 

Bridge, and National Canyons at levels 7-12 ft above the 

base of the formation. Unfortunately, the gastropods from 

National Canyon were misplaced and never were seen by 

the writer.

Among the bellerophontaceans, Bellerophon (Bellerophon) sp. is a fairly widespread form, occurring in five collections and rather common locally in the Anthracospirifer 

occiduus coquinoid bed in the middle cliff unit in the 

Guano Cave section. The shell material at all the localities 

is coarsely recrystallized and the writer cannot be sure that 

only one species is present. Euphemites was recognized at 

National Canyon and Retispira at Bridge Canyon, near the 

base of the lower slope unit at both localities.

The euomphalacean Straparollus (Euomphalus) sp. was 

recognized at nine localities, represented generally by less 

than three specimens at each. Seven species of pleurotomariaceans are assigned to Baylea, Worthenial, Shansiella, Euconospim, and at least two unrecognized and probably new genera; all of them occur very sparsely.

Cephalopods

The platyceratacean Strophostylus sp. is represented by 

a single specimen at Bridge Canyon. Microdoma sp. (pi. 

F4, figs. 23-27), a distinctive subconical species having a 

subdued middle row of nodes on each whorl, is well represented in collections from the Separation and Bridge 

Canyon sections. Anomphalus sp. is rare at Separation 

Canyon and a much larger species, listed as N. gen. aff. 

Anomphalus n. sp. is represented by two specimens from 

the middle cliff unit in the Guano Cave section.

The neritaceans include Naticopsis (Naticopsis) sp. 

recognized at two localities, one of which has also yielded 

another form that cannot be identified as to genus and may 

or may not be a neritacean. Higher-spired gastropods include one questionably referred to Taosia and others 

assigned to Meekospira and Donaldina, and to unidentified genera. A single fragment of a nautiloid resembling 

Liroceros and assigned to that genus with question was 

found in the middle cliff unit in the Guano Cave section.

Echinoderms, trilobites, and fish

All of the echinoderm remains are fragmental, but clearly both crinoids, represented by columnals, and echinoids, 

by spines, were present in the fauna.

The most common trilobite remains are pygidia found at 

eight localities and referred with various degrees of confidence to Paladin sp. One, from National Canyon, was 

identified by E. L. Yochelson as Ditomopygel sp. indet. 

Several unidentified librogenae (but probably belonging to 

Paladin) and an incomplete hypostome were also noted.

D. H. Dunkle has identified a fish spine from the east 

side of Toroweap Valley in beds of probable Atokan age as 

Deltodus sp., mercurii Newberry. Moreover, he assigned a 

fish dentition also from the upper slope unit in the Guano 

Cave section to Deltodus sp., as well as other specimens 

from fairly low in the lower slope unit in the Parashant, 

Separation, and Andrus Canyon sections.

FAUNA OF THE 

LOWER SLOPE UNIT

An overall abundance of Composita, particularly those 

referred to C. gibbosa Mather and C. ovata Mather, and of 

Anthracospirifer, especially A. tanoensis Sutherland and 

Harlow, characterize the fauna of the lower slope unit of 

the Watahomigi Formation. No productoid brachiopods 

have been recorded from this unit. This brachiopod assemblage is similar in composition to the rather monotonous fauna that occurs in the middle part of an equivalent 

section of Morrowan age in the Great Basin, which also is 

dominated by Composita and Anthracospirifer, except 

that there the predominant spiriferoid is Anthracospirifer 

occiduus (Sadlick). A. occiduus appears in the upper part 

of the lower slope unit in the vicinity of the Guano Cave 

section, but has a rather limited lateral distribution in that 

area. Punctospirifer transversus (McChesney) has a similarly limited lateral distribution. It is very abundant in the 

middle part of the lower slope unit, but restricted to the 

eastern part of the area studied, in several canyons flanking Toroweap Valley (see table Fl).

One striking feature of the lower 13 ft of the formation 

at several localities is the diversity of small pelecypods and 

gastropods. This considerable diversity was noted at 

Bridge, Separation and National Canyons. By far the 

greatest number of gastropod species in the Watahomigi 

Formation occur at these localities. Another characteristic 

of the fauna of the lower slope unit is that it is composed of 

species that do not exceed 2.5 cm in long dimension; many 

of the shells are much smaller.

In summary, the following features characterize the 

fauna of the lower slope unit: (1) predominance of Composita and Anthracospirifer, (2) absence of productoid brachiopods, (3) high diversity locally of molluscs and brachiopods in the lower 13 feet but rather monotonous assemblage of relatively few species throughout most of the unit, 

and (4) scarcity of large shells.
122 THE SUPAI GROUP OF GRAND CANYON

FAUNA OF THE 

MIDDLE CLIFF UNIT

In contrast to that of the lower slope unit, the fauna of 

the middle cliff unit is composed of species that generally 

grow to a size greater than 2.5 cm. This coincides with a 

predominance of shallow water limestone, indicating optimum conditions for the development of shelf-dwelling 

organisms. Anthracospirifer occiduus is by far the most 

abundant species, at least in the vicinity of Guano Cave, 

where a virtual coquina of these shells occurs locally. Productoid brachiopods are fairly common in some beds and 

at least five species have been recognized. The unit can be 

divided roughly into two parts stratigraphically by the 

larger Linoproductus species. L. sp. A occurs in the lower 

half and L. nodosus (Newberry) is restricted to the upper 

half. Molluscan species in this unit also tend to be larger 

than those in the lower slope unit.

In summary, the middle cliff unit is characterized by 

(1) fairly large brachiopods and mollusks, (2) presence of 

several species of productoids, (3) great abundance locally 

of Anthracospirifer occiduus (Sadlick), and (4) moderate 

diversity of species.

FAUNA OF THE 

UPPER SLOPE UNIT

Beds assigned to the upper slope unit of the Watahomigi 

Formation (see table C2) have yielded fossils at three localities: in the Hidden Canyon and Guano Cave sections 

(USGS collns. 22231-PC, 25130-PC, and one numbered) 

and on the east side of Toroweap Valley (USGS colln. 

21579-PC). The fossils from these localities are listed on 

table Fl, but it might be helpful to list them separately 

here. A composite list of the fossils identified in the five 

collections is as follows:

Trepostomatous bryozoan, ramose form

Stenoporoid, incrusting form

Fenestellal sp. indet.

Rhomboporoid bryozoan

Orbiculoidea meekana (Whitfield)

Orthotetacean, gen. & sp. indet.

Pulchratial picuris Sutherland and Harlow

Rhynchonelloid cf. Cupulorostrum sp.

Composita ovata Mather

Crurithyris planoconvexa (Hall)

Anthracospirifer tanoensis Sutherland and Harlow

A. newberryi Sutherland and Harlow

Promytilus sp.

Myalina (Myalina) sp. B

Myalinid, gen. & sp. indet.

Aviculopecten gravidus Gordon and Pojeta?

Echinoid spines

Crinoid columnals

Paladin sp.

Deltodus mercurii Newberry

Deltodus sp.

It is clear from the foregoing list of fossils, many of 

which occur also in lower beds, that the megafauna is of 

little use to distinguish beds of Atokan age from those of 

Morrowan age. Only when distinctive restricted species, 

such as Linoproductus nodosus, are present is this possible. The dating of the upper slope unit as Atokan has had 

to rely on fusulinid evidence.

CORRELATION WITH 

THE TYPE MORROWAN 

AND ATOKAN

The lower slope and middle cliff units of the Watahomigi 

Formation contain typical Morrowan brachiopods including Schizophoria altirostris (Mather), Pulchratial picuris 

Sutherland and Harlow, Linoproductus nodosus 

(Newberry), L. sp. A, L. pumilis Sutherland and Harlow, 

Composita gibbosa Mather, C. ovata Mather, Anthracospirifer tanoensis Sutherland and Harlow, A. newberryi 

Sutherland and Harlow, A. occiduus Sadlick, and Punctospirifer transversus (McChesney). Although some of these 

have ranges that extend either above or below the Morrowan, their occurrence in association is typical of a fauna 

of Morrowan age.

Among the species restricted to rocks of Morrowan 

age are Linoproductus nodosus (Newberry) and L. sp. A. 

These are part of continuum, in the opinion of T. W. 

Henry (oral commun., 1976), who has been studying the 

Morrowan brachiopod faunas in Arkansas and Oklahoma. This evolutionary line began with L. eastoni Gordon 

in the lower Morrowan Hale Formation. L. eastoni was 

originally described by Gordon (1975, p. D51) from the 

Cameron Creek Member of the Tyler Formation of Montana and the Amsden Formation of Wyoming; T. W. 

Henry (oral commun., 1976) has recognized it in the Hale 

Formation. The three species in this continuum have convex ventral areas that bear coarse spines. In L. eastoni, the 

coarse spines of the ventral area are accompanied by finer 

spines ornamenting the flanks.

In the Brentwood Limestone Member, which constitutes 

the lower part of the Bloyd Shale in the type Morrowan 

section, L. eastoni is replaced by L. sp. A, which bears a 

zigzag row of coarse spines on the venter, forming a band 1
BIOSTRATIGRAPHY OF THE WATAHOMIGI FORMATION 123

cm wide; no spines are present on the flanks (Henry and 

Sutherland, 1977, pi. 2, fig. 5).

In the upper Morrowan Dye Shale, Kessler Limestone, 

and Trace Creek Shale Members of the Bloyd Shale L. sp. 

A has evolved into L. nodosus, which bears a linear median row of coarse spines. The upper Morrowan beds are 

Middle Pennsylvanian in age and this stratigraphic interval 

coincides approximately with the range zone of L. 

nodosus, the name bearer of the Linoproductus nodosus 

Zone (Sutherland and Henry, 1975, p. 274; Henry and 

Sutherland, 1977, p. 110).

In the Watahomigi Formation, L. nodosus is confined to 

the upper part of the middle cliff unit, where it has been 

found at two localities. L. sp. A occurs lower down in the 

middle cliff at three localities; it is a late form of this species, having the spine band roughly 0.5 cm wide.

The lower 13 ft of the formation contains faunas of considerable diversity in the Snap, Separation, Bridge, and 

National Canyon sections. The writer has observed that 

the greatest faunal diversity in Morrowan rocks in the type 

region (Arkansas) is found in the Brentwood Limestone 

Member of the Bloyd Shale. The considerable faunal diversity of these lower Watahomigi collections, the absence of 

species known to be restricted to the Hale Formation, and 

the relatively advanced development of Anthracospirifer 

tanoensis in this lower part of the formation lead the writer 

to conclude that the lower slope unit of the Watahomigi 

Formation should be correlated principally with the Brentwood Limestone Member of the Bloyd Shale and that no 

Hale equivalents are present.

To summarize, the lower slope unit of the Watahomigi 

and the lower part of the middle cliff unit are middle Morrowan and correlate with the Brentwood-Woolsey part of 

the type Morrowan section in Arkansas (see fig. Fl). The 

upper part of the middle cliff unit, containing Linoproductus nodosus, is late Morrowan in age. The relatively minor 

thickness of these late Morrowan beds in the Watahomigi 

and the presence of the widely distributed conglomerate 

bed above suggest that a hiatus is present and that part of 

the Morrowan is missing.

The presence of Profusulinella and Fusulinella in collections from the upper slope unit of the Watahomigi, identified by Douglass, indicates an early Atokan age for this 

unit. However, as these are reworked (R. C. Douglass, 

oral commun., 1978) and occur virtually together, it is entirely possible that the Profusulinella Zone actually is not 

represented and the upper part of the Watahomigi begins 

in the Fusulinella Zone. Profusulinella is not known in the 

Atoka Formation in Arkansas, but has been reported from 

the Barnett Hill Formation, the lowest unit of Atokan age 

in Coal County, Oklahoma. As Fusulinella has been found 

in the Atoka Formation in Crawford County, Arkansas, as 

low as the Winslowoceras henbesti Ammonoid Zone, 

roughly 590 ft above the base, the earlier zone of Profusulinella should be sought in older parts of the formation. It should coincide with part of the Diaboloceras 

varicostatum Zone and occur in the basal few hundred feet 

of the formation (Gordon and Sutherland, 1975).

CORRELATION WITH 

OTHER WESTERN 

AMERICAN FORMATIONS

Other western strata that were deposited at about the 

same time as the Watahomigi Formation include the following (see fig. Fl): the middle part of the Ely Limestone in 

eastern Nevada and western Utah, the upper and thicker 

part of the Lake Point Limestone in the northern Oquirrh 

Mountains, Utah, and the upper part of the West Canyon 

Limestone of the Oquirrh Group, and also the basal part of 

the overlying Butterfield Peaks Formation in the central 

and southern Oquirrh Mountains. Eastward, the equivalents of the Watahomigi include the lower part of the La 

Pasada Formation of north-central New Mexico. In the 

northern Arbuckle Mountains of Oklahoma, the Wapanucka Limestone and overlying Barnett Hill Formation are 

Watahomigi equivalents and, in the southern Arbuckle 

Mountains, the Golf Course Formation (excluding the 

lower part of the Primrose Sandstone Member), as well as 

the overlying Bostwick Conglomerate Member of the Lake 

Murray Formation. In the nearby Ouachita Mountains 

region, the Johns Valley Shale and the overlying basal part 

of the Atoka Formation are Watahomigi equivalents and, 

as stated earlier, the Bloyd Shale and basal part of the 

Atoka Formation in the southern part of the Ozark region.

CORRELATION WITH 

STANDARD EUROPEAN 

SECTIONS

The ammonoids of the type Morrowan section permit 

correlation with the standard European Carboniferous succession. A recent comparison of the Arkansas succession 

with that of Europe (Saunders and others, 1977) indicates 

that the ammonoids of the Bloyd Shale have their equivalents in the Westphalian A and lower part of Westphalian 

B Substages. The lower and middle units of the Watahomigi are probably of Westphalian A age. The upper beds 

of Atokan age within the Watahomigi Formation would 

probably be Westphalian B equivalents (fig. Fl).

Correlations by means of ammonoids with stratigraphic 

sections in the European part of the Soviet Union indicate 

that the Arkansas beds equivalent to the Watahomigi Formation are correlative to the Bashkirian Provincial Stage
124 THE SUPAI GROUP OF GRAND CANYON

SYSTEM

PENNSYLVANIAN

SERIES

LLI

Q 

Q

S

DC 

LLI

|

PROVINCIAL SERIES ANDSUBDIVISIONS

ATOKAN

MORROWAN

LOWER

UPPER

MIDDLE

LOWER

NW ARKANSAS 

TYPE 

MORROWAN 

SECTION

Atoka 

Formation 

(part)

_0> 

CO

CO

T3 

0

m

Formation Hale 

Trace 

Creek 

Shale 

Member

Kessler 

Limestone 

Member

Dye 

Shale 

Member

Woolsey 

2lMember

Brentwood 

Limestone 

Member

Prairie 

Grove 

Member

Cane 

Hill 

Member

OUACHITA 

REGION, 

WESTERN 

ARKANSAS

Atoka 

Formation 

(part)

Johns

Valley 

Shale

Jackfork 

Sandstone1

Tl VALLEYCHOCTAW 

BLOCK, SE 

OKLAHOMA

Atoka 

Formation 

(part)

Wapanucka 

Limestone

Springer 

Formation2

NORTHERN 

ARBUCKLE 

MOUNTAINS, 

OKLAHOMA

Barnett 

Hill 

Formation

Wapanucka 

Limestone

Union 

Valley 

Sandstone

Unnamed 

shale

SOUTHERN 

ARBUCKLE 

MOUNTAINS, 

OKLAHOMA

Lake Murray Formation

Formation Golf Course 

Q.

£

LU

0) 

D)

C

Q. 

CO

Griffin 

Member

Bostwick 

Conglomerate 

Member

Otterville 

Limestone 

Member

Unnamed 

shale

Joliff 

Member

Gene 

Autry 

Shale 

Member

Primrose 

Member 

(upper part)

Unnamed 

shale

Primrose 

Member 

(lower part)

Unnamed 

shale

Lake 

Ardmore 

Sandstone 

Member

NORTHCENTRAL 

NEW 

MEXICO

P 

Fo

La 

asac 

rmat 

part

a 

ion

)

GRAND CANYON 

REGION, NORTHERN 

ARIZONA

tT

CO 

Q.

0> 

|

Q.

3 

O

(B

'<o

Q. 

3 

CO

— ^\

^ Watahomigi Formation

^^~

——

Up 

sic 

ur

_-^~

^-~ —

Mic 

cl 

ur

Lov 

sic

Ul

per 

pe 

lit

_-/-

die 

ff

lit

ver 

pe

lit

— --~.

r—

'May include rocks older than shown

2The formation in this area includes rocks much younger than at the type locality

FIGURE F1.—Correlation of Lower and lower Middle Pennsylvanian formations in the
BIOSTRATIGRAPHY OF THE WATAHOMIGI FORMATION 125

SOUTHERN 

OQUIRRH 

MOUNTAINS, 

UTAH

Q.

O

'5

CT

O

Butter-field 

Peaks 

Formation 

(part)

West

Canyon 

Limestone

Manning 

Canyon 

Shale 

(part)

NORTHERN 

OQUIRRH 

MOUNTAINS, 

UTAH

Q. 

O

'5

CT 

O

Erda 

Formation 

(part)

Lake

Point 

Limestone

(part)

EASTERN 

NEVADA 

AND 

WESTERN 

UTAH

Ely

Limestone

(lower part)

NW 

EUROPE

i U-1

•O •"" 

CO

B

A

C

B

STAGE

Z 

0.

CO

UJ

Z

E

z

U.S.S.R.

UJ 

CO

BASHKIRIAN

south-central and southwestern United States.

of the southern Ural Mountains, as originally defined. In 

1974, the base of the Bashkirian was officially lowered to 

coincide with the base of the middle Carboniferous (same 

as the base of the Pennsylvanian System in the United 

States). The new Bashkirian Stage includes equivalents of 

the Hale Formation, as well as the higher beds (fig. Fl). 

Thus, the lower part of the Bashkirian Stage as presently 

defined includes beds older than the base of the Watahomigi, but the top of the Bashkirian and top of the 

Watahomigi are roughly equivalent.

CLIMATE

The presence in the Watahomigi Formation of numerous 

myalinid pelecypods as well as fusulinids suggests that the 

waters of the Early and early Middle Pennsylvanian seas in 

this region were shallow and fairly warm. In this regard, 

the total absence of rugose solitary corals and the scarcity 

of colonial corals is puzzling, but may have been due to 

local high-energy conditions and to excessive amounts of 

silt and sand being deposited along with the carbonates.

PALEOGEOGRAPHIC 

CONSIDERATIONS

The fossil evidence permits one to draw several relatively firm conclusions as to the sequence of geologic 

events in the Grand Canyon region during the period of 

Watahomigi deposition. The beginning of the Pennsylvanian found the Grand Canyon region a positive area, elevated above sea level. Watahomigi marine deposition 

probably commenced in Brentwood (middle Morrowan) 

time on a deeply eroded surface mainly of Meramecian, 

but also of Chesterian, rocks. This submergence and beginning of deposition correlates with a period of intense tectonic activity in the Ouachita trough in southeastern Oklahoma, when many huge erratic blocks derived from earlier 

formations were loosened by the development of growth 

faults along the Ouachita frontal belt and slid into the 

trough (Gordon and Stone, 1977).

The presence in the Watahomigi of species such as Aviculopecten gravidus Gordon and Pojeta, previously known 

only from the Amsden Formation of Wyoming, and 

Schizodus amplus Meek and Worthen, a characteristic Midcontinent pelecypod, indicates that links were established at 

that time with seas on both sides of the transcontinental arch 

that divided the waters of the great Cordilleran sea in the 

West from the even larger eastern interior sea, which lay 

between the arch and the Appalachian highland and at times 

covered much of the American Midcontinent.
126 THE SUPAI GROUP OF GRAND CANYON

How long a time the Grand Canyon region remained 

above sea level, during the depositional hiatus marked by 

the conglomerate at the base of the upper slope unit of the 

Watahomigi, is not clear. As stated earlier, a considerable 

part of the upper Morrowan probably is missing; also, the 

fusulinid evidence indicates that beds of earliest Atokan 

age may likewise be absent. Nevertheless, at some moment 

early in the Atokan, the region was again shallowly submerged and deposition of the upper part of the Watahomigi as well as the entire Manakacha Formation took 

place without further interruption.

REFERENCES CITED

Gordon, Mackenzie, Jr., 1975, Brachiopoda of the Amsden Formation 

(Mississippian and Pennsylvanian) of Wyoming: U.S. Geological 

Survey Professional Paper 848-D, 86 p.

Gordon, Mackenzie, Jr., and Pojeta, John, Jr., 1975, Pelecypoda and 

rostroconchia of the Amsden Formation (Mississippian and Pennsylvanian) of Wyoming: U.S. Geological Survey Professional Paper 

848-E, 24 p.

Gordon, Mackenzie, Jr., and Stone, C. G., 1977, Correlation of the Carboniferous rocks of the Ouachita trough with those of the adjacent 

foreland, in Symposium on the geology of the Ouachita Mountains, 

v. 1, Stratigraphy, sedimentology, petrography, tectonics, and 

paleontology: Arkansas Geological Commission, p. 70-91.

Gordon, Mackenzie, Jr., and Sutherland, P. K., 1975, Ammonoids of the 

upper Wapanucka Limestone and their bearing on the MorrowanAtokan boundary in Oklahoma [abs.]: American Association of 

Petroleum Geologists and Society of Economic Paleontologists and 

Mineralogists, Annual Meeting Abstracts, v. 2, p. 30.

Henry, T. W., and Sutherland, P. K., 1977. Brachiopod biostratigraphy 

of Morrowan Series (Pennsylvanian) in northwestern Arkansas and 

northeastern Oklahoma in P. K. Sutherland and W. L. Manger, eds., 

Mississippian-Pennsylvanian boundary in northeastern Oklahoma 

and northwestern Arkansas: Oklahoma Geological Survey Guidebook 18, p. 107-115.

McKee, E. D., 1963, Nomenclature for lithologic subdivisions of the Mississippian Redwall Limestone, Arizona in Geological Survey 

Research, 1963: U.S. Geological Survey Professional Paper 475-C, 

p. C28-C29.

McKee, E. D., and Gutschick, R. C., 1969, History of the Redwall Limestone of northern Arizona: Geological Society of America Memoir 

114, 726 p.

Saunders, W. B., Manger, W. L., and Gordon, Mackenzie, Jr., 1977, 

Upper Mississippian and Lower and Middle Pennsylvanian ammonoid biostratigraphy of northern Arkansas, in P. K. Sutherland and 

W. L. Manger, eds., Mississippian-Pennsylvanian boundary in 

northeastern Oklahoma and northwestern Arkansas: Oklahoma 

Geological Survey Guidebook 18, p. 117-132.

Sutherland, P. K., and Harlow, F. H., 1973, Pennsylvanian brachiopods 

and biostratigraphy in southern Sangre de Cristo Mountains, New 

Mexico: New Mexico Bureau of Mines and Mineral Resources Memoir 27, 173 p.

Sutherland, P. K., and Henry, T. W., 1975, Brachiopod zonation of the 

Lower and Middle Pennsylvanian System in the United States of 

America [abs.]: International Congress on Stratigraphy and Carboniferous Geology, 8th, Moscow, 1975, Abstracts of Papers, 

p. 274-275.

128 THE SUPAI GROUP OF GRAND CANYON

PLATE F1

Brachiopods

[Figures natural size unless otherwise indicated on plate]

FIGURES 1, 2. Orbiculoidea meekana (Whitfield)

Ventral and side views of ventral valve internal mold showing patches of shell (USNM 256803),

east side of Toroweap Valley, USGS colln. 21579-PC, upper slope unit. 

3-5. Schizophoria altirostris (Mather)?

Side and dorsal views of poorly preserved brachial valve (USNM 256804) and ventral view of

pedicle valve (USNM 256805), Guano Cave section, USGS colln. 25324-PC, middle cliff unit. 

6, 7. Orthotetes sp. A

Ventral view and interarea of pedicle valve (USNM 256806) from Twin Springs Canyon, USGS

colln. 21581-PC, lower slope unit. 

8-10. Derbyia sp. A

Dorsal view of one specimen and side and ventral views of another (Grand Canyon Museum,

nos. 4714 and 20595) Parashant Canyon, lower slope unit. 

11, 17-19. Buxtonial sp.

Side, ventral, enlarged ventral, and posterior views of a pedicle valve (USNS 256807) from Hidden Canyon, USGS colln. 22228-PC, middle cliff unit. 

12-16. Linoproducius nodosus (Newberry)

12-14. Posterior, ventral, and side views of pedicle valve (USNM 256812) from Guano Cave section, USGS colln. 21576-PC, middle cliff unit. 

15, 16. Ventral and side views of pedicle valve (USNM 256813) from Snap Canyon, USGS colln.

22270-PC, same unit. 

20-22. Linoproductus pumilis Sutherland and Harlow

Enlarged ventral, anterior, and side views of pedicle valve (USNM 256814) from Guano Cave

section, USGS colln. 25324-PC, middle cliff unit. 

23-25. Buxtonia sp.

23. Ventral view of brachial valve (USNM 256808) from Guano Cave section, USGS colln.

25324-PC, middle cliff unit. 

24, 25. Side and ventral views of incomplete pedicle valve attached to brachial valve (USNM

256809) from Snap Canyon, USGS colln. 22270-PC, same unit. 

26-32. Pulchratial picuris Sutherland and Harlow

26-29. Posterior, ventral, anterior, and side views of pedicle valve (USNM 256810) from Guano

Cave section, USGS colln. 25324-PC, middle cliff unit.

30-32. Ventral, side, and enlarged ventral views of another pedicle valve (USNM 256811) from 

Snap Canyon, USGS colln. 22270-PC, same unit.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1173 PLATE Fl

X2

ORBICULOIDEA, SCHIZOPHORIA, ORTHOTETES, DERBYIA, BUXTONIA, 

LINOPRODUCTUS, AND PULCHRATIA
130 THE SUPAI GROUP OF GRAND CANYON

PLATE F2

Brachiopods

[Figures natural size unless otherwise indicated on plate]

FIGURES 1-6. Crurithyris planoconvexa (Shumard)

Enlarged posterior, dorsal, enlarged dorsal, side, ventral, and anterior views of well-preserved

specimen (Grand Canyon Museum GC-224A) from Guano Cave section, upper slope unit. 

7-16. N. gen. aff. Anteridocus, n. sp.

Enlarged posterior, dorsal, side, ventral, and anterior views of one specimen (USNM 256815) and 

enlarged dorsal, posterior, side, anterior, and ventral views of another (USNM 256816) from 

National Canyon, USGS colln. 25127-PC, lower slope unit. 

17-31. Composita ovata Mather

Dorsal, posterior, ventral, side, and anterior views of two specimens (USNM 256817, 256818) from

Whitmore Wash, USGS colln. 22235-PC, lower slope unit. 

Enlarged dorsal, posterior, ventral, side, and anterior views of an immature specimen (USNM

256819) from west side of Toroweap Valley, USGS colln. 22976-PC, lower slope unit. 

32-41. Composita gibbosa Mather

Enlarged dorsal, posterior, ventral, side, and anterior views of two specimens (Grand Canyon

Museum, nos. 15244,15252) from Parashant Canyon, lower slope unit. 

42-46. Dielasmoid, gen. and sp. indet.

Enlarged dorsal, posterior, ventral, side, and anterior views of a specimen (USNM 256833) from National Canyon, USGS colln. 25127-PC, lower slope unit.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1173 PLATE F2

X2

22 32 X2

28 X2

^^

X2

35 ar X2

31 X2

X2 39

X2 42

43 —— X4

44 ————X4

CRURITHYRIS, COMPOSITA, AND DIELASMA
132 THE SUPAI GROUP OF GRAND CANYON

PLATE F3

Brachiopods

[Figures natural size unless otherwise indicated on plate]

FIGURES 1-5. Composita sp. (transverse form)

Dorsal, posterior, ventral, anterior, and side views of a large individual (USNM 256820) from

Guano Cave section, USGS colln. 25324-PC, middle cliff unit. 

6, 7. Composita subtilita (Hall)

Ventral and side views of pedicle valve (USNM 256821) from same collection as last. 

8-16. Anthracospirifer occiduus (Sadlick)

Ventral view of one specimen, dorsal, ventral, anterior, and side views of another specimen, dorsal 

and anterior views of a third, and anterior and ventral views of a fourth (USNM 256822-256825, 

inclusive) from Guano Cave section, USGS colln. 25324-PC, middle cliff unit. 

17-19. Anthracospirifer tanoensis Sutherland and Harlow

Anterior and ventral views of pedicle valve (USNM 256826) from Hidden Canyon, USGS colln.

22226-PC (float); unit not known. 

Dorsal view of brachial valve, (USNM 256827) from west side of Toroweap Valley, USGS colln.

22976-PC, lower slope unit. 

20, 21. Anthracospirifer newberryi Sutherland and Harlow

Pedicle valve (USNM 256828) from Guano Cave section, USGS colln. 25130-PC, upper slope unit. 

Brachial valve (USNM 256829) from same collection as last. 

22-24. Punctospirifer transversus (McChesney)

Enlarged views of brachial and pedicle valves (USNM 256830, 256831) from Whitmore Wash, USGS

colln. 22235-PC, lower slope unit.

Slab (USNM 256832) from west side of Toroweap Valley (enlarged), USGS colln. 22978-PC, lower 

slope unit.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1173 PLATE F3 

>J

COMPOSITA, ANTHRACOSPIRIFER, AND PUNCTOSPIRIFER
134 THE SUPAI GROUP OF GRAND CANYON

PLATE F4

Pelecypods and gastropods

[Figures natural size unless otherwise indicated on plate]

FIGURES 1, 4. Phestia sp.

Left valve of moderately large specimen (USNM 256836) from Guano Cave section, USGS colln.

25324-PC, middle cliff unit. 

Left valve of small juvenile specimen (USNM 256835) from Bridge Canyon section, USGS colln.

27031-PC, lower slope unit. 

2, 3. Nuculopsis (Nuculanella) sp.

Enlarged views of left valve and dorsum of a specimen (USNM 256834) from same collection as last. 

5, 6. Aviculopecten sp. B

Left valve and enlarged view of same (USNM 256841) from Snap Canyon section, USGS colln.

22267-PC, lower slope unit. 

7, 8. Septimyalina sp. A

Enlarged views of right valve and dorsum of same specimen (USNM 256839) from National

Canyon, USGS colln. 25127-PC, lower slope unit. 

9, 10. Myalina (Myalina) sp. A

Top view of paired valves and view of left valve of same specimen (Grand Canyon Museum, no. 

11212) from east side of Toroweap Valley, McKee locality FS44, upper slope unit.

11. Promytilus sp.

Enlarged view of right valve (USNM 256837) from Bridge Canyon section, USGS colln. 27031-PC, 

lower slope unit.

12. Myalina (Myalina) sp. B

Left valve (USNM 256838) from Snap Canyon, USGS colln. 22267-PC, lower slope unit.

13. Septimyalina sp. B

Left valve (USNM 256840) from Guano Cave section, USGS colln. 25324-PC, middle cliff unit.

14. Edmondial sp.

Right valve in chert (Museum of Northern Arizona, no. G2 6734) from section south of Pica, bed 5,

lower slope unit. 

15, 16. Permophorus sp.

Right valve and enlargement of same (USNM 256848) from Separation Canyon, USGS colln. 

25139-PC, lower slope unit.

17. Aviculopecten gravidus Gordon and Pojeta

Enlarged view of left valve (USNM 256842) from Bridge Canyon section, USGS colln. 27031-PC, 

lower slope unit.

18. Schizodus sp. B

Left valve (USNM 256847) from Hidden Canyon section, USGS colln. 22227-PC, lower slope unit.

19. Schizodus sp. A

Left valve (USNM 256846) from Snap Canyon section, USGS colln. 2267-PC, lower slope unit. 

20-22. Schizodus amplus Meek and Worthen

Left valve (USNM 256843) from Snap Canyon section, USGS colln. 2267-PC, lower slope unit. 

Right valve (USNM 256844) from Guano Cave section, USGS colln. 25324-PC, middle cliff unit. 

Internal mold of right valve, showing impression of internal ridge alongside posterior adductor 

muscle scar (USNM 256845) from Hidden Canyon section, USGS colln. 22227-PC, middle cliff 

unit. 

23-27. Microdoma n. sp.

Enlarged top, bottom, and apertural views of specimen (USNM 256850) from Bridge Canyon section, USGS colln. 27031-PC, lower slope unit.

Enlarged side and top views of another specimen (USNM 256851) from same collection. 

28. Wilkingia terminalis (Hall)

Left valve (USNM 256849) from Guano Cave section, USGS colln. 25324-PC, middle cliff unit.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1173 PLATE F4

28

PHESTIA, NUCULOPSIS, AVICULOPECTEN, SEPTIMYALINA, MYALINA, PROMYTILUS, 

EDMONDIA , PERMOPHORUS, SCHIZODUS, MICRODOMA, AND WILKINGIA

THE SUPAI GROUP OF GRAND CANYON

PRE-SUPAI BURIED VALLEYS

Chapter G 

By GEORGE H. BILLINGSLEY and EDWIN D. McKEE

Contents

General character ...... ...........

Location and orientation . ........

Lithology . . . . ........

Lower unit (terrestrial) ........

Middle and upper units (marine) 

Flora and Fauna ..................

Lower unit ..................

Middle unit .................

Upper unit . ...........

Correlation and age . ...........

Pre-Supai warping ................

References cited .................

Page

139

139

139

139

139

139

139

143

144

144

145

145

137
138 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURF G1. Photograph of buried valley deposits below Watahomigi Formation near Quartermaster

Canyon . . ... ........... . . 140

G2. Photograph of buried valley deposits below Watahomigi Formation at 217 Mile Canyon . 140 

G3. A map of western part of Grand Canyon showing localities of principal pre-Supai valleyfill outcrops ......... .. ..................... .. .. . 141

G4. Generalized stratigraphic sections of principal pre-Supai valley deposits ., ,,.,, r ,,,, ,. r , 142 

G5. Diagram of transgression and regression . ,,.,,,,..,.. 146

PLATE G1. Fossil brachiopods from pre-Supai valley-fill deposits ................................ 148

G2. Assemblage of small invertebrates in coquinoid limestone ................. .....,•,... 150

G3. Foraminifera in the upper unit of pre-Supai valley fill deposits ......................... 152

Tables

Page

TABLE G1. Depth and width of pre-Supai buried valleys . . . . .............. .................. 141

G2. Invertebrate megafossils from lower limestone unit of valley-fill deposits ................. 143
PRE-SUPAI BURIED VALLEYS 139

GENERAL CHARACTER

In much of the Grand Canyon region, basal deposits of 

the Watahomigi Formation of the Supai Group rest upon a 

relatively flat and even surface at the top of the Redwall 

Limestone, as described in chapter C. Mostly the surface is 

formed on limestone strata of Early Mississippian age 

(Osagian and Merimecian); features of karst topography 

and also shallow channels are characteristic.

Recent observations by G. H. Billingsley, made while 

mapping in western Grand Canyon, have revealed in 

many places the presence of buried valleys in the Redwall 

below the conglomerate at the base of the Watahomigi. 

These valleys average about 1,000 ft in width and 280 ft in 

depth with a maximum depth of 401 ft near Quartermaster 

Canyon. Apparently the valleys are parts of an extensive 

drainage system formed after Redwall deposition had 

ceased; they were completely filled with sediment, partly 

marine and partly continental, by the close of Late 

Mississippian (Chesterian) time.

Implicit in the observed relations of erosion and sedimentation in the pre-Watahomigi valleys are certain tectonic events. The area must have been uplifted more than 

400 ft above sea level in the vicinity of Quartermaster 

Canyon about the middle of Mississippian time to have 

permitted dissection to that depth. Following uplift and 

erosion, relative sea level must have changed frequently 

during Chesterian time, causing first fluvial deposits and 

later marine deposits to accumulate and fill the valleys. By 

Early Pennsylvanian (Morrowan) time, the valleys of 

Chesterian age had been completely filled with sediment 

and the western sea had transgressed the broad level surface to begin Supai deposition.

LOCATION AND 

ORIENTATION

Buried-valley profiles are exposed in the walls of western 

Grand Canyon (figs. Gl, G2) from the towers above 

Guano Cave, herein called Bat Tower, in the west to Diamond Creek in the east, approximately 40 river miles, and 

from Diamond Creek in the south to Granite Park in the 

north, approximately 16 river miles. The seven principal 

exposures that have been examined are listed with depth 

and with width (where measured) (table Gl), and they are 

shown on the regional map (fig. G3).

Valley-fill deposits have been correlated from section to 

section on the basis of lithology, fossils, and rock color. 

They show lithologic continuity, but considerable variation in thickness. Drainage patterns, pebble imbrication, 

and the distribution of the fluvial detrital sediments at the 

base all indicate a westward-flowing drainage system that 

apparently consisted of two major streams. These streams

joined in the vicinity of the present Surprise Canyon to 

form a single main stream. The northern tributary valley is 

referred to as the Granite Park valley; the southern tributary valley as Separation valley. Both apparently had 

small tributaries of their own and contain essentially the 

same sequence of strata filling them.

LITHOLOGY

Lower unit (terrestrial)

The basal unit in most of the valley-fill sequences (fig. 

G4) consists of detrital sediment considered to be fluvial 

and composed largely of pebble and cobble conglomerate, 

and calcareous sandstone.

The conglomerate is composed largely of rounded to 

subrounded chert pebbles and cobbles, ranging in diameter 

from 0.25 to 5 in. They are red, yellow, gray, and white, 

and occur in a matrix of poorly sorted, relatively coarse 

quartz sand with various types of cement. The cement differs from place to place and includes siliceous, calcareous, 

and ferrugineous types. The conglomerate is associated 

with and overlain by pale-yellow and dark-gray calcareous 

sandstone that is medium to coarse grained and locally 

cross-stratified. Quartz grains are generally rounded. 

These deposits contain petrified wood, leaf imprints, 

spores, and other plant remains. Locally, the color of the 

sandstone may be dark gray or black because of the abundance of carbonaceous plant fragments.

Middle and upper units (marine)

The upper part of the buried-valley deposits generally 

consists of three lithologic units: (1) massive, cliff-forming, 

thin-bedded, brown to purple limestone; (2) calcareous 

red-brown sandstone and siltstone; overlain by (3) cliff of 

an upper, relatively thin, gray limestone (fig. G4). This sequence generally weathers into two weak cliffs separated 

by a slope. Both limestone units contain marine fossils; the 

sandstone and siltstone between contain many worm trails 

and cuspate ripple marks. These marine units together 

range from about 150 to 300 ft in thickness and, in most 

places, are thicker than the underlying fluviatile unit.

FLORA AND FAUNA 

Lower unit

The basal unit of the valley-fill deposits that underlie the 

Watahomigi Formation locally contains poorly preserved 

plant remains in its sandstone facies. A collection from 

these rocks, examined by S. H. Mamay, contained two
140 THE SUPAI GROUP OF GRAND CANYON

FIGURE G1.—Buried valley deposits below Watahomigi Formation near Quartermaster Canyon, western Grand Canyon, Ariz. Valley width, 1,250 ft; valley depth, 401 ft.

•/f

f\.. ''H

*. v 

• —.'wvAyi

FIGURE G2.—Buried valley below Watahomigi Formation at 217 Mile Canyon, western Grand Canyon, Ariz. Valley depth, 212 ft; valley width,

1,050 ft. Refer to figure G1 for explanation of symbols.
PRE-SUPAI BURIED VALLEYS 141

EXPLANATION

Buried valley deposits

D Upper unit (limestone cliff)

C Upper unit (sandstone slope)

B Lower limestone Middle unit (limestone cliff)

A Lower unit (sandstone and conglomerate slope) 

S Slump block 

Pm Manakacha Formation 

Pw Watahomigi Formation 

Redwall Limestone

Mrm Mooney Falls Member

Mrt Thunder Springs Member

Mrw Whitmore Wash Member 

Dtb Temple Butte Limestone

TABLE G1.—Pre-Supai buried valleys

[Leaders (—) indicate not measured]

Outcrop No. and locality

1

2 

3 

4,5 

6,7 

8,9 

10

Quartermaster Canyon . . .

209 Mile Canyon .......

Depth (ft)

267 

401 

201 

221-254 

283-331 

197-226 

212

Width (ft)

1,205 

1,000

1,050

specimens of fern, five sphenopsids, and several unidentifiable axial scraps. The fern was described by Mamay (written commun., 1978) as "a very delicate, small-pinnuled 

sphenopterid or pecopterid." The "sphenopsid fragments 

are parts of the fruiting organs of a phyllothecoid plant;

Grand Canyon Rim 

Redwall Limestone Rim

10 MILES

FIGURE G3.—Western part of Grand Canyon, Ariz., showing principal pre-Supai valley-fill outcrops (solid circles): 1, Bat Tower; 2, Quartermaster 

Canyon; 3, Surprise Canyon; 4 and 5, Separation Canyon; 6 and 7, 209 Mile Canyon; 8 and 9, Granite Park; 10, 217 Mile Canyon.
(1)

Bat 

Tower

50-

100-150-

200-

250- -T^I=

(2)

Quartermaster 

Canyon

(3)

Surprise 

Canyon

(4)

Separation 

Canyon

(5)

Separation 

Canyon

(6)

209 Mile 

Canyon

(7)

209 Mile 

Canyon

(8)

Granite 

Park

(9)

Granite 

Park

300-

350-

400^

(10) Base of

217 Mile Watahomigi

Canyon Formation

Upper 

unit

EXPLANATION

Conglomerate

Sandstone

Shaly mudstone

Limestone

Carbonaceous wood fragments

FIGURE G4.—Generalized stratigraphic sections of principal buried-valley outcrops. Numbers at base refer to thickness (in feet). Lines between sections 

show general correlation of lower, middle, and upper units. Section localities are shown on figure G3.

Middle 

unit

H

5C/5Cgn53

8

T) 

§

Oa 

n
PRE-SUPAI BURIED VALLEYS 143

some of these are relatively slender, but others have stout 

axes, short internodes and short narrow bracts."

Samples also from the basal unit have been prepared and 

examined for palynomorphs. Two collections from the 

Granite Park locality were determined by R. M. Kosanke 

(written commun., 1978) to contain "abundant organic 

matter including fragments of fusinite, semifusinite, spores 

and pollen grains." The following palynomorphs were 

identified:

Anapiculatisporites condnnus Playford 

Anaplanisporites globulus (Butterworth and Williams)

Smith and Butterworth

Aurorasporaso/isorfus Hoffmeister, Staplin, andMalloy 

Calamospora sp.

ConvolutisporafloridaHottmeister, Staplin, andMalloy 

C. sp.

Dictyotriletes cf. D. clatriformis (Artuz) Sullivan 

Granulatisporites granulatus Ibrahim 

G. sp.

Hadrohercos stereon Felix and Burbridge 

Knoxisporites triradiatus Hoffmeister, Staplin, and Malloy 

Lycosporaspp.

Punctatisporites cf. P. heterofiliferous Felix and Burbridge 

P. cf. P. nitidus Hoffmeister, Staplin, and Malloy 

P. pseudolevatus Hoffmeister, Staplin, and Malloy 

P. solidus Hacquebard 

P. validus Felix and Burbridge 

P. spp.

Recticulatisporites sp. 

Schulzospora rara Kosanke 

Triquitritessp. 

Monosaccates 

Unassigned (? algal)

Middle unit

A fauna consisting of 187 specimens of invertebrate 

megafossils has been collected from the lower massive 

limestone (middle unit) of the valley-fill deposits below the 

Supai Group. The specimens have been examined by Mackenzie Gordon, Jr. (written commun., 1978), who has 

listed from the collections "one coral, eleven brachiopods, 

ten mollusks, remains of blastoids and crinoids, one trilobite, and a shark dentition" (table G2; pi. Gl). Gordon further stated that the most common form is a small Inflatia 

(pi. G2) that resembles I. clydensis (Girty) of the Fayetteville Shale of Arkansas and Oklahoma, but is not identical 

with that species.

A zone of corals occurs in the middle unit (massive limestone) of the valley-fill sequence at Granite Park in Grand 

Canyon (fig. G3). A collection of 16 poorly preserved 

specimens was submitted to W. J. Sando who made the following determinations:

Michelinia sp. 

Barytichisma sp.

The corals are not specifically identifiable. Michelinia ranges from 

Devonian to Permian and is little help for age determination. BarytichTABLE G 2.—In vertebrate fossils from lower limestone unit of valley-fill 

deposits below Watahomigi Formation, western Grand Canyon, Ariz.

[Identifications by Mackenzie Cordon, Jr.]

Locality and 

USCS collection No.

No. of 

specimens

217 Mile Canyon, Coconino Co.

27422-PC Inflatia aff. /. clydensis (Girty) 25 

Composita subquadrata (Hall)? 1

27423-PC Paladin sp. 1 

shark dentition 1

Granite Park, Coconino Co.

27424-PC Coral

27425-PC Michelinia sp. 1 

Inflatia aff. /. clydensis (Girty) 11 

D/aphragmus? sp. 1 

Ovatia sp. Fragment 

Pugnoides sp. 2 

Torynifer setiger (Hall)? 1 

Nucu/ops/s? sp. indet. 1 

Aviculopecten sp. 1 

Schizodus sp. indet. 1 

Cypricardinia sp. 1 

Plagioglypta sp. 4 fragments 

Retispira sp. 2 

Glabrocingulum cf. C.

quadrigatum Sadlick & Nielson 1 

Neilsonia sp. 1 

Anematina 1 

Microdoma sp. 1 

Pentremite ambulacrum Fragment 

crinoidal debris 

Paladin sp. 3

Separation Canyon, Mojave Co.

27426-PC Schizophoria sp. Fragment 

Inflatia aff. /. clydensis (Girty) 35 

Anthracospirifer sp. A 8

Surprise Canyon, Mojave Co.

27427-PC Michelinia sp. 1

Orthotetoid, gen. & sp. indet. Fragment

Inflatia aff. /. clydensis (Girty) 57

Ovatia sp. (small) 1

Pugnoides sp. 6

Torynifer setiger (Hall)? 1

Anthracospirifer sp. A 7

Beecheria sp. 1

Pectenoid, gen. & sp. indet. Fragment

Pelecypod indet. Fragment

Bellerophon (Bellerophon) sp. 3

209 Mile Canyon, Mojave Co.

27428-PC Brachiopod shell detritus

Straparollus (Straparollus?) sp. indet. 1 

Pelmatozoan detritus

isma is a relatively rare horn coral. Species have been described from 

the Morrowan of Texas, Arkansas, and Colorado and from the late 

Chesterian of Wyoming (Mamet Zone 18 or 19). I have also identified 

this genus in beds of late Chesterian (Zone 17) age in Idaho. The possible age range indicated by the corals is late Chesterian (Zone 17) to 

Morrowan.
144 THE SUPAI GROUP OF GRAND CANYON

Sandy limestone from the coral zone in the middle 

unit at Granite Park, examined in thin section by Betty 

Skipp, contains abundant bryozoan and pelmatozoan 

debris, and lesser amounts of ostracode, trilobite, and 

brachiopod detritus. The alga, Asphaltina sp., is present, 

along with a tubular calcareous foraminifer, Pseudoglomospira sp.

A thin-section of the lower limestone (middle unit) from 

the Bat Tower section (sec. 1, fig. G4) contains ostracodes, 

gastropods, and some pelmatozoan debris.

Upper unit

The highest limestone (upper unit) of the valley-fill deposits, like the lower limestone, contains a marine invertebrate fauna. The number and variety of species, however, 

is much more limited. Collections of megafossils from 

three localities were examined by Mackenzie Gordon, Jr., 

who reported the following forms:

No. of specimens 

Separation Canyon, Mojave Co.

Inflatia or Sandia sp. ........................................ 3

Bat Tower

Inflatia or Sandia sp. ........................................ 2

Surprise Canyon, Mojave Co.

Composite ovata Mather ..................................... 6

C. gibbosa Mather .......................................... 4

Anthracospirifer aff. A.

curvilateralis (Easton) ..................................... 5

Schizodus sp. ............................................... 1

Gordon stated (written commun., 1978) that these 

species "are not as definitive" as those in the lower limestone. "The Coraposz'tas***resemble the species found in 

the Watahomigi Formation" and "the Anthracospirifer is 

not the same species as that found in the lower limestone" 

(middle unit) of the valley-fill deposits.

Foraminifera and algae from limestone of the upper unit, 

representative of Mamet foraminiferal Zone 19 (Mamet 

and Skipp, 1970), uppermost Mississippian (uppermost 

Chesterian), have been identified by Betty Skipp (written 

commun., 1978), from the Granite Park and Bat Tower 

sections. The following genera and species are present:

Bat Tower 

Foraminifera:

Endothyra excellens (D. E. N. Zeller, 1953)

Eosigmoilina explicata Ganelina, 1956

"Eosigmoilina" rugosa Brazhnikova, 1964

Neoarchaediscus spp. 

Granite Park 

Algae (green):

lOrtonella sp. 

Foraminifera:

apterrinellids

Endothyra sp.

Pseudoglomospira sp.

Volvotextularia sp.

Zellerina sp.

CORRELATION AND AGE

Evidence from three sources—brachiopods, foraminifers, 

and spores—indicates a Late Mississippian age for the 

lower, middle, and upper units of the valley-fill deposits.

Brachiopod evidence of a Late Mississippian age for the 

valley-fill deposits is furnished by the "predominance of 

Inflatia and the presence of Torynifer" in the lower 

limestone unit and by a specimen of Glabrocingulum, said 

to be almost identical with a late Chesterian species from 

the Chainman Shale of Utah (Mackenzie Gordon, Jr., written commun., 1978).

Evidence of Late Mississippian age supplied by spores in 

the basal sandstone unit is discussed by R. M. Kosanke 

(written commun., 1978) as follows:

Convolutispora florida and Knoxisporites triradiatus were originally 

described from the Hardinsburg Formation of Illinois. They were 

[later] reported by Felix and Burbridge (1967, p. 362) as occurring in 

the Goddard, Springer, and Morrow Formations of Oklahoma. Punctatisporites solidus was originally described from the Horton group 

(Mississippian) of Nova Scotia***[and has been reported] occurring 

throughout the Springer Formation of Oklahoma.

The spore taxon Hadrohercos stereon of the Grand Canyon sequence also occurs in Oklahoma, in the Goddard 

Shale Member, and in shales overlying the Rod Club and 

Overbrook Sandstone Members (formerly considered 

Pennsylvanian) of the Springer Formation. These three 

members and overlying shales have recently been assigned 

a Chesterian age. Thus, the known upper occurrence of H. 

stereon is now within the Upper Mississippian according to 

Gordon (1976).

A summary of the floral evidence concerning age is as 

follows: Three taxa are considered indicative of the Upper 

Mississippian:

Anaplanisporites globulus 

Auroraspora solisortus 

Hadrohercos stereon

The following taxa occur in Upper Mississippian rocks, but 

also may be found in older Mississippian rocks:

Anapiculatisporites concinnus 

Dictyotriletes cf. D. clatriformis

The balance of the taxa identified occur in both Mississippian and Pennsylvanian rocks.

The most important foraminifers for age determination 

in the upper unit are the eosigmoilinids (Betty Skipp, written commun., 1978). Eosigmoilina explicata Ganelina is 

considered to occur exclusively within Zone 19 as understood by this author. "Eosigmoilina" rugosa Brazhnikova 

(= Quasiarchaediscus of Mamet) may have a more extensive range (Mamet, 1975; Brenckle and others, 1977; P. L.
PRE-SUPAI BURIED VALLEYS 145

Brenckle, oral commun., 1977). Plate G3 illustrates both 

forms from the upper limestone in the Bat Tower section. 

Eosigmoilina explicata Ganelina has been reported from 

the type Chesterian region in southern Illinois (Brenckle 

and others, 1977), and from Arkansas (Brenckle, 1977). 

"Eosigmoilina" rugosa Brazhnikova has been reported 

from Nevada (Brenckle, 1973, identified as Eosigmoilina 

and Quasiarchaediscus), and the Alaskan Cordillera (Armstrong and Mamet, 1977), in addition to the occurrences 

listed above for E. explicata. Eosigmoilinids also are 

known to occur in other parts of the Midcontinent and 

Cordilleran regions of the United States (Hewitt and Conil, 

1969; Sando, Mamet, and Dutro, 1969; Mamet and others, 

1971; Mamet, 1975).

Study of calcareous foraminifera west of the Grand Canyon area in the Battleship Wash Formation (Langenheim 

and Langenheim, 1965) and Indian Springs Formation 

(Webster and Lane, 1967) 1 of the Arrow Canyon Range, 

Nevada, in conjunction with the discovery of the preSupai valleys, led to the construction of the correlation 

chart of figure G5. Correlation of foraminiferal faunas 

from Nevada east to the western Grand Canyon area suggests that uplift of the Redwall Limestone and erosion that 

preceded the deposition of the sediments in the pre-Supai 

valleys occurred in early Chesterian time. A faunal gap 

representing foraminiferal Zone 16s is present within the 

Battleship Wash Formation. This gap is interpreted to 

represent a regression of the Redwall epeiric sea, followed 

by a transgression during the time of F.Z. (foraminiferal 

Zone) 17-18, another regression that corresponds in 

general to F.Z. 18 time, and then another transgression 

that spread eastward into the Grand Canyon area. The 

F.Z. 19 faunas of the upper limestone of the pre-Supai 

valleys were deposited during the latter transgression. It is 

not known for certain whether the lower limestone of the 

valleys also represents F.Z. 19 time or may be a remnant of 

the older (F.Z. 17-18) transgression. It is Betty Skipp's 

opinion, based on available faunal data, that at least some 

of the pre-Supai valley deposits probably were laid down 

during the F.Z. 17-18 transgression (fig. G5).

PRE-SUPAI WARPING

Evidence of regional warping in strata underlying the 

Supai was first noted in the area of eastern Grand Canyon. 

Near the Bunker (Tanner) Trail, the contact between the 

Redwall Limestone and Supai Group is an angular unconformity (McKee and Gutschick, 1969, p. 79, fig. 32a). 

"Forty feet of eastward-dipping thin beds of the Horseshoe 

Mesa Member are bevelled from east to west and overlain 

by red, shaly mudstone." Farther north, "westwarddipping strata of Redwall are bevelled along one-half mile 

of exposure."

'Includes lower part of Bird Spring Formation of Hewitt (1"31)

In Snap Canyon in the Grand Wash Cliffs, which form 

the western end of Grand Canyon, further evidence of 

crustal uplift, probably by warping, in pre-Supai strata was 

recorded during the measuring of Supai sections by E. D. 

McKee during the 1960's. The measured section at that 

locality (fig. A6, sec. E-E', profile 27) shows the middle or 

cliff unit of the Watahomigi Formation resting on the Redwall Limestone. The bottom unit of the Watahomigi is missing. Presumably, this absence of the unit is due to 

nondeposition in an area that was relatively high or upwarped at the time of initial marine transgression at the start 

of Supai time.

In addition to evidence of epirogenic movement furnished in the two areas cited above, confirmation that 

widespread uplift of Redwall strata occurred prior to 

Watahomigi time is found in the presence of the buried 

valleys discussed in this chapter. The valley at Quartermaster Canyon in western Grand Canyon, cut to a depth 

of 401 ft, gives a figure for the magnitude of uplift in that 

area. Depths of buried valleys farther east at Granite Park, 

217 Mile Canyon, and elsewhere show that base level in 

those areas was probably between 200 and 300 ft below the 

general land surface.

The valley-fill deposits containing a flora and fauna of 

late Chesterian age indicate that an uplift with warping of 

the Grand Canyon region must have taken place in late 

Meramecian or early Chesterian time, followed by a gradual rising of sea level as the valleys were filled, first with 

continental and then with marine sediments, prior to a major transgression of the sea at the beginning of Watahomigi 

deposition during Morrowan time.

REFERENCES CITED

Armstrong, A. K., and Mamet, B. L., 1977, Carboniferous microfacies, 

microfossils, and corals, Lisburne Group, Arctic Alaska: U.S. Geological Survey Professional Paper 849,144 p. [1978]

Brazhnikova, N. E., 1964, Studying Eosigmoiline from the Lower Carboniferous of the greater Donetz Basin [in Russian]: Akad. Nauk 

Ukrain. SSR, Ser. Strat. Paleont., no. 48, p. 3-15.

Brenckle, P. L., 1973, Smaller Mississippian and Lower Pennsylvanian 

calcareous foraminifers from Nevada: Cushman Foundation for 

Foraminiferal Research Special Publication 11, 82 p.

____1977, Foraminifers and other calcareous microfossils from Late 

Chesterian (Mississippian) strata of northern Arkansas: Oklahoma 

Geological Survey Guidebook 18, p. 73-88.

Brenckle, P. L., Lane, H. R., Manger, W. L., and Saunders, W. B., 1977, 

The Mississippian-Pennsylvanian boundary as an intercontinental 

biostratigraphic datum: Newsletters on Stratigraphy, v. 6, no. 2, 

p. 106-116.

Felix, C. J., and Burbridge, P. P., 1967, Palynology of the Springer Formation of southern Oklahoma, U.S.A.: Palaeontology, v. 10, no. 3, 

p. 349-425.

Ganelina, R. A., 1956, Foraminifera of the Visean sediments of the northwest region of the Moscow syncline [in Russian]: Vses. Neft. Nauchno-Issled. Geol.-Razved. Inst. Trudy 98, Mikrofauna SSSR no. 8, 

p. 31-159.
146 THE SUPAI GROUP OF GRAND CANYON

ICEBERG

CANYON

2

BRIDGE

CANYON

3

BRIGHT

ANGEL

4

ARROW CANYON

RANGE

1

NEVADA! ARIZONA

Callville Limestone I Watahomigi Formation

\ Bird Spring Formation 

(tower part) upper Mississippian deposits 

between RedwaU Limestone 

and Watahomigi Formation Indian Springs 

Formation 1

Battleship

Wash 

Formation 2

Yellowpme Limestone 

Member

Horseshoe Mesa Membe 

(Redwall Limestone)

n Limestone Member to Mooney Falls Member (Redwall Limestone)

Anchor 

Limestone Member

Thunder Springs Member (Redwall Limesto

Dawn Limestone Member

WhitmoreWash Member (Redwall Limestone

Crystal Pass 

Limestone Member 

(Sultan Limestone

Temple Butte Limestone

^Webster and Lane (1967); includes lower part of Bird Spring Formation of Hewitt (1931) 

^Langenheim and Langenheim (1965).

FIGURE G5.—Diagram of the transgressions and regressions of the 

Mississippian seas across southern Nevada and northern Arizona 

based on time lines represented by the foraminiferal zones of Mamet 

(Mamet and Skipp, 1970). Microfaunal studies of Brenckle (1973; written commun., 1977), and Skipp in the Arrow Canyon Range, Nevada, 

and Skipp (1969) in northern Arizona, form the basis for zonal ranges

of the formations. The pattern of transgressions and regressions of 

the Redwall sea is modified from McKee and Gutschick (1969, fig. 

26). Large arrows indicate major transgressions and regressions. 

Smaller arrows indicate inferred minor transgressions and regressions. Modified from Skipp (1978).

Gordon, Mackenzie, Jr., 1976, Correlation chart of carboniferous rocks 

in Arkansas and Oklahoma, in G. V. Cohee and W. B. Wright, 

Changes in stratigraphic nomenclature by the U.S. Geological 

Survey, 1975: U.S. Geological Survey Bulletin 1422-A, p. A54, 

A56-A57.

Hewett, D. F., 1931, Geology and ore deposits of the Goodsprings quadrangle, Nevada: U.S. Geological Survey Professional Paper 162, 

172 p.

Hewitt, P. C., and Conil, R., 1969, Foraminiferes du Meramecien et du 

Chesterien des Etats-Unis (Tennesse): Bulletin de la Societe Beige de 

Geologic, de Paleontologie, et d' Hydrologie, v. 78, p. 175-185.

Langenheim, V.A.M., and Langenheim, R. L., Jr., 1965, The Bird Spring 

Group, Chesterian through Wolfcampian, at Arrow Canyon, Arrow 

Canyon Range, Clark County, Nevada: Illinois State Academy of 

Science Transactions, v. 58, no. 4, p. 225-240.

McKee, E. D., and Gutschick, R. C., 1969, History of the Redwall Limestone of northern Arizona: Geological Society of America Memoir 

114, 726 p.

Mamet, B. L., 1975, Carboniferous foraminifera and algae of the Amsden 

Formation (Mississippian and Pennsylvanian) of Wyoming: U.S. 

Geological Survey Professional Paper 848-B, p. B1-B18.
PRE-SUPAI BURIED VALLEYS 147

Mamet, B. L., and Skipp, Betty, 1970, Preliminary foraminiferal correlations of Early Carboniferous strata in the North American Cordillera: Les Congres et Colloques de 1'Universite de Liege, v. 55, 

p. 327-348.

Mamet, B. L., Skipp, Betty, Sando, W. J., and Mapel, W. }., 1971, Biostratigraphy of Upper Mississippian and associated Carboniferous 

rocks in south-central Idaho: American Association of Petroleum 

Geologists Bulletin, v. 55, no. 1, p. 20-33.

Sando, W. J., Mamet, B. L., and Dutro, J. T., Jr., 1969, Carboniferous 

megafaunal and microfaunal zonation in the northern Cordillera of 

the United States: U.S. Geological Survey Professional Paper 613-E, 

p. E1-E29.

Skipp, Betty, 1969, Foraminifera, Chapter 5, in McKee, E. D., and Gutschick, R. C., History of the Redwall Limestone of northern Arizona: 

Geological Society of America Memoir 114, p. 173-256.

____1978, Great Basin Region, Chapter P, in Craig, L. C., Conners, 

C. W., and others, Mississippian System of the conterminous United 

States: U.S. Geological Survey Professional Paper 1010, Part 1, 

p. 273-328.

Webster, G. D., and Lane, N. G., 1967, Mississippian-Pennsylvanian 

boundary in southern Nevada, in Essays in paleontology and stratigraphy—Raymond C. Moore commemorative volume: Kansas University Department of Geology Special Publication 2, p. 503-522.

Zeller, D.E.N., 1953, Endothyroid foraminifers and ancestral fusulinids 

from the type Chesterian (Upper Mississippian): Journal of 

Paleontology, v. 27, p. 183-199.
148 THE SUPAI GROUP OF GRAND CANYON

PLATE G1

Fossil brachiopods from pre-Supai valley-fill deposits, western Grand Canyon, Ariz.

[Natural size unless otherwise indicated. Photographs provided by Mackenzie Gordon, Jr.]

FIGURES 1-6. Inflatia aff. I. clydensis (Girty). Lower limestone unit.

1. 3, 6.Ventral, enlarged oblique (to show diagonal auricular spine row) and side views of a typical 

specimen (USNM 265888) from USGS colln. 27427-PC, Surprise Canyon.

2. 4, 5.Enlarged oblique, ventral, and side views of another specimen (USNM 265889) from the

same collection. 

7-9. Anthracospiriferct. A. curvilateralis (Easton). Upper limestone unit.

Enlarged posterior, ventral, and enlarged ventral views of a specimen (USNM 265895) from USGS

colln. 27421-PC, Surprise Canyon. 

10-14. Cranaenal sp. Lower limestone unit.

10-12.Dorsal, anterior, and side views of a brachial valve (USNM 265896) from USGS colln.

27220-PC, Surprise Canyon. 

13, 14.Ventral and side views of a pedicle valve (USNM 265897) from USGS colln. 27427-PC,

Surprise Canyon. 

15-18. Torynifer cf. T. setiger (Hall). Lower limestone unit.

15. 17.Views, enlarged and natural size, of a pedicle valve (USNM 265892) from USGS colln. 

27425-PC, Granite Park.

16. 18.View and enlarged view of another pedicle valve (USNM 265893) from USGS colln.

27427-PC, Surprise Canyon. 

19-21. Composita cf. C. ovata Mather. Upper limestone unit.

Dorsal view and enlarged dorsal and anterior views of a specimen (USNM 265890) from USGS

colln. 27421-PC, Surprise Canyon. 

22-26. Composita cf. C. elongata Dunbar and Condra. Upper limestone unit.

Dorsal view and enlarged posterior, ventral, anterior, and side views of a specimen (USNM 265891)

from the same collection as the last. 

27-29. Anthracospirifer sp. A. Lower limestone unit.

Enlarged ventral, ventral, and posterior views of an incomplete pedicle valve (USNM 265894) from 

USGS colln. 27427-PC, Surprise Canyon.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1173 PLATE Gl

xr/2

29

INFLATIA, ANTHRACOSPIRIFER, CRANAENA?, TORYNIFER, AND COMPOSITA
150 THE SUPAI GROUP OF GRAND CANYON

PLATE G2

Assemblage of small invertebrates (X 3) in coquinoid limestone from the lower limestone (middle unit) of a valley

fill, USGS colln. 27425-PC, Granite Park, Coconino County, Ariz.

[Photograph provided by Mackenzie Gordon, Jr.]

FIGURE 1. Inflatia aff. /. clydensis (Girty), fragment

2. Ovatia sp., fragment

3. Composite sp., fragment

4. Glabrocingulum (Glabrocingulum) cf. G. (G.) quadrigatum Sadlick and Nielsen

5. Neilsoniasp.

6. Anematina sp.

7. Paladin sp.: A, librigena (free cheek), B, pygidium
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1173 G2

INFLATIA, OVATIA, COMPOSITA, GLABROCINGULUM, NEILSONIA, ANEMATINA, AND PALADIN
152 THE SUPAI GROUP OF GRAND CANYON

PLATE G3

Foraminifera in the upper unit of pre-Supai valley-fill deposits, western Grand Canyon, Ariz.

[Identification and photographs by Betty Skipp. All figuresx200]

FIGURES 1-4. Eosigmoilina rugosa Brazhnikova, 1964. Bat Tower section, upper limestone, Mamet foraminiferal Zone 

19 (uppermost Chesterian).

1. Axial section, USNM 258929.

2. Axial section, USNM 258930.

3. Transverse section, USNM 258931.

4. Transverse section, USNM 258932.

5-9. Eosigmoilina explicata Ganelina, 1956. Bat Tower section, upper limestone, Mamet foraminiferal Zone 

19 (uppermost Chesterian).

5. Axial section, USNM 258933.

6. Sagittal section, USNM 258934.

7. Near-sagittal section, USNM 258935.

8. Near-sagittal section, USNM 258936.

9. Near-sagittal section, USNM 258937.

10. Pseudoglomospira sp. Bat Tower section, upper limestone, Mamet foraminiferal Zone 19 (uppermost 

Chesterian), USNM 258938.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1173 PLATE G3

EOSIGMOILINA, AND PSEUDOGLOMOSPIRA

THE SUPAI GROUP OF GRAND CANYON

EROSION SURFACES

Chapter H 

By EDWIN D. McKEE

Contents

Surfaces of erosion in the Supai Croup .......................

Erosion surfaces at base of the Watahomigi Formation . . ....

Probable erosion surface at base of Atokan-age rocks ........ ...

Erosion surfaces within cliff unit of the Manakacha Formation .....

Erosion surface at base of the Wescogame Formation . ........

Erosion surface at base of the Esplanade Sandstone ..... ........

Erosion surfaces within the Esplanade Sandstone .....

Erosion surface at contact of Esplanade Sandstone and Hermit Shale 

References cited .........................................

Page

157

157

159

160

160

163

165

169

171

155
156 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURES H1-H4. Sketches of:

H1. East-west cross-section showing principal lithologic units, surfaces of erosion, hiatuses, and key conglomerate beds, Supai Group . 158 

H2. Erosion surface at contact of Redwall Limestone and Watahomigi Formation ......... 159

H3. Erosion surfaces within Manakacha Formation ........ ...... 163

H4. Erosion surface at 61 ft above base of cliff unit, Manakacha Formation ....... 164

H5. Photographs of channels on erosion surfaces within Manakacha Formation . ........ 165

H6. Photographs of erosion surfaces at top of Manakacha, base of Wescogame ........ 166

H7. Sketches of channeled surface, base of Wescogame ............................ 167

H8. Sketches of channeled surface, base of Wescogame (cliff unit) .................... 168

H9. Photographs of unconformable surface between Manakacha and Wescogame ....... 169

H10. Sketches of channeled surface at base of Wescogame Formation ................. 170

H11. Photographs of surface erosion at top of Wescogame ................. 172

HI2. Sketches of channeled surface, top of Wescogame ... ....... ..... 173

H13. Sketches of channeled surface, top of Wescogame overlain by Esplanade Sandstone ....... . . ... ... .... ... ..... . . 174

H14. Photographs of unconformable surface between Esplanade Sandstone and Hermit

Shale . . .. ...... ..... ............ 175

H15. Sketches of erosional unconformity between Hermit and Esplanade ......,.,....,. 176

Tables

Page

TABLE H1. Thickness of conglomerate and relief on erosion surface at principal unconformities of Supai Group ................................. .... ........ 161

H2. Erosion surfaces in cliff unit of the Manakacha Formation .... .... 162

H3. Characteristics of erosion surface, base of Wescogame Formation ................. 172

H4. Unconformity at top of the Esplanade Sandstone ............................... 175
EROSION SURFACES 157

SURFACES OF EROSION 

IN THE SUPAI GROUP

Strata of the Supai Group are superficially alike because 

they are generally reddish brown and they weather into 

certain characteristic topographic forms that are repeated 

numerous times in each stratigraphic section. Detailed 

studies in a large area, however, clearly indicate that these 

strata do not constitute a single unified unit, but form a sequence of distinctive deposits. Furthermore, each major 

stratigraphic unit is separated from the underlying and 

overlying sequences by a well-marked boundary consisting 

of a surface of erosion and (or) a blanket of conglomerate 

(fig. HI).

Widespread surfaces of erosion separate both the Manakacha and Wescogame Formations and the Wescogame 

Formation and Esplanade Sandstone of the Supai Group; 

erosion surfaces also occur at the bottom and the top of the 

group. All of these surfaces are irregular and include channels. The basal contact of Atokan-age strata probably also 

represents a time of nondeposition, but no scouring has 

been noted there. All of these erosion surfaces except at the 

Hermit-Supai boundary are overlain by conglomerates. 

The surface at the top of the Supai is overlain by, and most 

of its channels are filled with, fine detrital rocks.

The basal conglomerates of the formations in the Supai 

are distinctive and widespread (chapter J), and have proved 

very useful in correlating strata within the Supai Group. 

Most of the unconformities in the Supai represent significant 

hiatuses as confirmed by fossils from above and below 

(chapter E). Unconformities within the Manakacha Formation and the Esplanade Sandstone are apparently only locally developed.

EROSION SURFACES 

AT BASE OF THE 

WATAHOMIGI FORMATION

The irregular basal contact of the Watahomigi is the 

record of a long period of erosion. The existence of this 

widespread unconformity was noted by Darton (1910, 

p. 13) and by Noble (1922, p. 61). Noble stated, "I have 

presented evidence that this surface is a plane of unconformity by erosion," and he justified revision of the Redwall-Supai boundary on the presence of this feature. The 

character and extent of the erosion surface have been described and illustrated in an earlier publication by the 

author (McKee and Gutschick, 1969, p. 74), and will be 

summarized here.

In most places the hiatus between the Watahomigi Formation and the Redwall Limestone represents all of Late

Mississippian time and the earliest part of Morrowan or 

Early Pennsylvanian time. Generally, in the Grand Canyon region, the uppermost strata of the Redwall Limestone 

are of Early Mississippian age. Rocks of Late Mississippian 

(Chesterian) age have been reported from eastern Grand 

Canyon only at Bright Angel Trail, but, from western 

Grand Canyon, in several recently recognized pre-Supai 

valleys described in chapter G. In the overlying Supai 

Group, the oldest known fossils are from the base of the 

Watahomigi; their age has been determined by Mackenzie 

Gordon, Jr. (chapters E and F) as younger than earliest 

Morrowan.

During early stages in development of the unconformity 

between the Redwall Limestone and the Watahomigi Formation, the region of western Grand Canyon must have 

been moderately elevated, for stream-cut valleys dissect 

the upper Redwall surface in that area to depths in excess 

of 400 ft. These valleys, as described in chapter G, must 

have been eroded soon after Redwall deposition ceased for 

they were subsequently filled with fluvial, followed by 

marine, deposits of Chesterian age. Later, by the time this 

region was being inundated by a broad advance of the 

Morrowan sea, with basal Watahomigi strata being deposited, the regional surface again was flat and low.

The surface on which the basal conglomerate of the 

Supai accumulated, as seen in the walls of Grand Canyon, 

had very little relief with only shallow depressions and low 

ridges or mesas interrupting its evenness. The valleys of 

Late Mississippian age had been filled and the topography, 

in general, was determined by the resistance of the Redwall 

Limestone, which was eroded into ledges and steps forming the sides of channels (fig. H2C, D, E) or the margins of 

low mesas (fig. \\2A, B). Elsewhere erosion has formed sink 

holes and related karst features. In table 11 of McKee and 

Gutschick (1969, p. 74), the amount of relief on this surface is summarized. Channels as much as 40 ft deep occur 

at Toroweap Valley and 30 ft at Whitmore Wash.

The lithology of the basal beds of the Watahomigi Formation seems to reflect the amount of relief on the upper 

surface of the Redwall Limestone. In the bottoms of channels and other depressions, the lowest beds of the Watahomigi generally consist of conglomerate, red mudstone, 

or both. Higher in the channels or on the flat surfaces 

bordering them, shaly red mudstone is most common. Still 

higher in the sequence, and on the tops of low buried 

plateaus, the rocks consist of thin-bedded limestone. 

Typically, the lower part of the Watahomigi is composed 

of conglomerate, mudstone, and limestone, in ascending 

order.

The evidence of karst topography on the upper surface 

of the Redwall Limestone in this region consists of mudand breccia-filled depressions, and red mud along the bedding planes and in the solution holes, of the limestone.
158 THE SUPAI GROUP OF GRAND CANYON

II

•i <

°- c

00 O

.E 'oo 

^
EROSION SURFACES 

EXPLANATION

159

Conglomerate 

Erosion surface

<? & Angular chert fragments

-70'-

I . I

' '

FIGURE H2.—Erosion surfaces at contact of the Redwall Limestone (R) 

and Watahomigi Formation (W), Grand Canyon, Ariz. A, Residual 

mounds at Thunder River Trail section; 8, relief at top of Redwall, 

east side of Havasu Canyon near Navajo Falls; C, unconformity at

These features are depicted in figure 31 of McKee and Gutschick (1969). In general, the intensity of solution illustrated by the ancient karst surface and the thickness of Mississippian strata removed by solution are much less in the 

Grand Canyon region than farther south in the Mogollon 

Rim area of central Arizona. Many excellent examples are 

in both places.

The environment of deposition represented by the overlying basal beds of the Watahomigi Formation apparently 

was marine. The basal strata consist of conglomerate that 

in many areas contains brachiopods and other marine 

fossils among the pebbles and in other areas contains relatively continuous beds of limestone. Cherty rubble, which

Fishtail Canyon, near Thunder River Trail; D, channel at S B Canyon; 

and £, conglomerate and channel at Tuckup Canyon. Vertical and 

horizontal distances in feet.

locally includes large blocks of Redwall Limestone and 

contorted layers of reddish-brown mudstone, probably accumulated within the karst topography during pre-Supai 

time, possibly pre-Pennsylvanian, before transgression of 

the Watahomigi sea.

PROBABLE EROSION 

SURFACE AT BASE OF 

ATOKAN-AGE ROCKS

The contact of the middle cliff unit and the upper slope 

unit of the Watahomigi Formation in the Grand Canyon
160 THE SUPAI GROUP OF GRAND CANYON

region probably is an unconformity. It is the boundary between rocks of Morrowan age and Atokan age as determined from fossils collected in the region (chapter E).

The contact of the middle and upper units of the Watahomigi is generally concealed by talus and does not provide evidence of channeling or dissection. A surface of erosion can be inferred, however, from the persistent basal 

(Atokan) conglomerate of the upper slope unit (fig. Jl) that 

consists largely of angular and closely packed pebbles of 

jasper and chert, and has been found at 17 scattered localities in the region. No appreciable relief has been noted 

below this gravel of the Atokan conglomerate in Grand 

Canyon (table Hi). Apparently, therefore, a very even, 

flat surface forms the contact between the marine deposits 

of Morrowan and Atokan age, indicating that no appreciable uplift of the area occurred during Early Pennsylvanian time. Certainly no narrow channels of 20- to 50-ft 

depth, such as occur in stratigraphic breaks above and below, have been found at this horizon.

EROSION SURFACES 

WITHIN CLIFF UNIT OF THE 

MANAKACHA FORMATION

These unconformities and conglomerate beds at 11 localities in the Grand Canyon have been recognized within the 

cliff unit of the Manakacha Formation. The evidences of 

erosion occur at various horizons ranging from the bottom 

to the top of the cliff unit (table H2) and so cannot represent parts of a single surface of erosion. At 5 localities they 

were found at or near the base of the cliff unit (fig. H3); at 

3 localities they were found from 50 to 70 ft above the 

base; and at 3 other localities, they were found in the upper 

part of the cliff unit, more than 100 ft above the base.

Channels on erosion surfaces of the cliff unit of the Manakacha Formation range in depth from 6 to 30 ft (table H2) 

and are as much as 200 ft wide in central Grand Canyon. 

Thin beds or lenses of gravel, 1 to 2 ft thick, lie on the bottom or along the sides of some channels. At other places, 

the channels are filled with reddish-brown, shaly mudstone (figs. H4, H5). The gravel consists largely of chert or 

jasper pebbles, but at Grandview Trail it is composed of 

limestone clasts.

The erosion surfaces are at several stratigraphic positions and seem to be discontinuous, which may be the 

result of local origin and intermittent development. The 

composition of the gravels indicates that the conglomeratic 

rocks probably were derived from nearby sources. During 

Atokan time, sedimentation probably was interrupted 

periodically and in various places, with local erosion and 

redeposition leaving its record. The possibility must be 

entertained, however, that any or all of the three groups of

erosion surfaces recorded in table H2 may represent traces 

or remnants of more widespread unconformities.

Because most of these local unconformities and conglomerates are within carbonate rock sequences, a marine 

origin seems likely. Scouring and the concentration of 

gravel on the sea floor is postulated, but changes in sea 

level accompanied by subaerial erosion and deposition 

may have been responsible for some of the stratigraphic 

breaks.

EROSION SURFACE 

AT BASE OF THE 

WESCOGAME FORMATION

A prominent unconformity, characterized by conspicuous channels in many places, occurs at the contact of the 

Manakacha and Wescogame Formations throughout most 

of the Grand Canyon region (fig. H6). This unconformity 

represents a hiatus that extends from Atokan or, possibly, 

early Des Moinesian time to Virgilian time, as determined 

from fossils (chapter E) collected both above and below the 

contact in western Grand Canyon.

This post-Manakacha erosion surface is especially conspicuous in exposures of central Grand Canyon where it 

occurs locally as an irregular and undulating surface, and 

elsewhere as narrow rounded channels between low ridges 

or platforms (figs. H7, H8). These features are especially 

well displayed in Havasu Canyon, the type locality of the 

Supai (figs. H9 and HlO), but also in National, Tuckup, 

and Kanab Canyons, Thunder River Trail, and in other 

localities of this area (fig. H6).

As indicated in table H3, channels on the erosion surface 

dissect several different types of rock in the region, but 

they are mostly in flat-bedded siltstone and mudstone in 

the eastern Grand Canyon, and in cross-bedded sandstone 

and limestone in the central and western parts of the canyon area. The channels are commonly from 5 to 20 ft deep, 

but are as much as 80 ft deep in Havasu Canyon. Other 

deep channels were observed in Tuckup, S B, and Snap 

Canyons (table Hi).

The hiatus between the Manakacha and Wescogame 

Formations, which probably involves most of Des Moinesian and Missourian time, seems to be of regional extent. In 

Nevada, "at Mountain Spring and at North Bird Spring 

Range a thin conglomerate separates the two systems" 

(Atokan and Virgilian) according to Welsh (1959, p. 59). 

At Beaver Dam Mountains in Utah, most of the Des 

Moinesian Series is missing and at Frenchman Mountain, 

Nevada, all of it is absent according to Steele (1959, table 

2). This "regional widespread unconformity between lower 

and upper Pennsylvanian sediments throughout the entire
TABLE HI.—Thickness of conglomerate and relief on erosion surface at principal unconformities of Supai Croup

[Congl., conglomerate; leaders (-) indicate not observed; +, present, but not measured]

No.

1a,b.

2. 

3. 

4. 

4a. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 

19. 

20. 

21a. 

21 b. 

22. 

23. 

24. 

25. 

26. 

27. 

28. 

30. 

31. 

32. 

34. 

35.

Measured section

Name

Near mile 22, Marble 

Canyon. 

Twentynine Mile Canyon . .

Bunker Trail .............

Bass Trail ...............

Kanab Canyon ...........

S B Canyon ..............

Tuckup Canyon ..........

Blue Mountain Canyon ....

Andrus Canyon ..........

Twin Springs Canyon ......

Snap Canyon ............

Watahomigi Formation

Congl.

thickness, 

in feet

4.0

12.0 

8.5 

0

2.0

+ 

+ 

2.5 

+ 

0

0

3.0 

7.5 

5.0 

11.0 

3.0 

5.5

4.0 

10.0 

2.5 

3.0

1.0 

5.0

2.5

Relief

Karst

None

Concealed 

Irregular 

None

None 

Karst 

None 

Concealed 

5-ft channel

5-ft channel 

Karst 

Irregular 

4-ft channel 

Channeled 

None

Karst 

Irregular 

3-ft channel

Irregular 

11 -ft relief 

Channeled

Irregular

Atokan strata

Congl. 

thickness, 

in feet

1.0

10.0

None 

3.0

1.0

8.5 

5.5 

3.5 

17.5 

3.0

7.0 

3.0 

6.0

6.0

7.5 

8.5

1.5

Relief

Solution 

channel

None 

Concealed

Irregular 

Channeled

Concealed 

None

None 

None 

do.

None

Wescogame Formation

Congl. 

thickness, 

in feet

4.0 

10.0 

1.0

1.0 

3.0

15.0

2.0 

1.0 

3.0

None

11.0

1.0 

2.0

8.0 

2.0 

3.0

2.0

Relief

Pockets 

Irregular 

Channeled

Concealed 

Channeled

80-ft channel

Irregular 

6-ft channel 

23-ft channel

Irregular 

Channeled

34-ft channel 

10-ft channel

Esplanade Sand

Congl. 

thickness, 

in feet

Lenses

5.0 

3.0

16.5

3.0 

17.0 

5.0 

15.0 

2.5 

2.5 

4.0 

5.5 

8.0

7.5 

3.0 

3.5 

7.0 

9.5

2.0

3.0 

35.0 

2.0 

1.0 

2.0 

2.0 

3.0 

11.0 

10.0

Relief

50-ft ch

Channe

4-ft cha

Irregula

Channe

15-ft ch

12-ft ch

4-ft cha

47-ft ch

45-ft ch

11-ft ch

19-ft ch

None 

Irregula

Irregula

Channe

None 

Irregula

Channe

'Uppermost sandstone ranges in thickness from 4 to 12 ft along 0.25 mi of outcrop.
TABLE H2.—Erosion surfaces in cliff unit of the Manakacha Formation

Measured section

National Canyon ......

Near mile 22, Marble

Canyon.

Dimension or 

composition of fill

100ft wide, 8 ft deep ....

100ft wide, 6 ft deep ....

limestone bed.

200 ft wide, 30 ft deep . . .

3-ft channel, contorted

limestone.

Contorted siltstone beds . .

150 ft wide, 10 ft deep

contorted beds.

limestone.

Underlying rock

Upper part, cliff unit

Sandstone, cross-bedded ........

bedded sandstone.

Middle part, cliff unit

Lower part, cliff unit

Mudstone ...................

Overlying rock 

(above pebble beds)

Compositio

in ch

............. d

............. d

............. d
EROSION SURFACES 163

FIGURE H3.—Channels on erosion surfaces within the Manakacha Formation, Grand Canyon, Ariz. A, Trough in jasper-banded limestone 

filled with sandy limestone, near base of formation, S B Canyon; 8, 

wavy surface of erosion at base of Manakacha cliff unit, near 

Twentyseven Mile Rapids in Marble Canyon.

eastern Great Basin, has caused more confusion in understanding the stratigraphy of the area than any other single 

factor" (Steele, 1959, p. 52).

EROSION SURFACE 

AT BASE OF THE 

ESPLANADE SANDSTONE

The most conspicuous and widespread of the various 

erosion surfaces that delineate formations of the Supai 

Group in Grand Canyon is the one that underlies the 

Esplanade Sandstone and marks the top of the Wescogame

Formation. This surface includes many channels of different sizes and shapes, interfluve surfaces consisting of small 

rounded hills, and broad flat plains (table HI). This unconformity occurs at the boundary between the Pennsylvanian and Permian Systems.

Most channel profiles at the Wescogame-Esplanade contact are semicircular (fig. Hll), some only a few feet deep, 

but others as much as 47 ft (Havasu Canyon) and 45 ft 

(National Canyon). Widths of the larger channels are as 

much as 5(30 ft. In profile, many channels are asymmetrical 

or irregular (figs. H12 and H13).

The record of unconformity between the Wescogame 

Formation and Esplanade Sandstone is locally complex. 

Rather than a single irregular surface of erosion at the top 

of the Wescogame and one basal conglomerate in the 

Esplanade, a zone consisting of two or more irregular surfaces of erosion and more than one conglomerate bed or 

lens occurs at some places. At six localities (S B Canyon, 

Havasu Canyon, National Canyon, Toroweap Valley, 

Whitmore Wash, and Blue Mountain Canyon) conglomerate beds occur at two horizons above the unconf ormable 

surface suggesting the repetition of a degradationaggradation cycle. Furthermore, in at least three localities 

conglomerate deposits are cut by channels of a younger 

erosion surface. Thus, more than one stage of erosion and 

deposition seems to be represented by unconformities 

associated with the basal part of the Esplanade Sandstone. 

On the other hand, this boundary was described as "gradational" by Fisher (1963, p. 153) and attributed to "extensive 

and continuous marine sedimentation in northwestern 

Arizona."

Before the close of Virgilian time and development of the 

post-Wescogame erosion surface, withdrawal of marine 

waters from the Grand Canyon region apparently took 

place. This is indicated by imprints of land plants in uppermost reddish-brown mudstones of the Wescogame. The 

conifer Walchia has been found in the upper part of the 

Wescogame at two localities (Hidden Canyon, Iceberg 

Canyon), together with shrinkage cracks, borings like 

those of worms, and other trace fossils, which are evidence 

of continental, probably alluvial, deposition prior to the 

time of unconformity.

The Grand Canyon region was elevated above sea level 

and an intricate pattern of drainage channels was eroded in 

the upper surface of the Wescogame before the Esplanade 

was deposited. Later, during transgression of the Permian 

sea, sediments of the Pakoon Limestone (McNair, 1951) 

accumulated in the western part of the region and sand of 

the Esplanade was deposited farther east.

A distinctive conglomerate, referred to as basal conglomerate of the Esplanade Sandstone, overlies the postWescogame surface of erosion in a majority of the 

localities (28 of 32) examined. This conglomerate consists 

mainly of well-rounded pebbles and cobbles of limestone
164 THE SUPAI GROUP OF GRAND CANYON

-• ••.• - .---—— -jr

9.5 5 ^-V^:-^^^

± 

A

-115

D

I ••>• ••^-^-^— -^z^-.^-_ I \-.--'.--••V^r^^r^.—- — —

EXPLANATION

Sandstone 

Cross-bedded

Calcareous 

Mudstone

?-tT

Cross-bedded sandy 

limestone

Conglomerate 

Limestone

FIGURE H4.—Erosion surfaces in the Manakacha Formation. A, Channel 

100 ft wide and 6 ft deep, near top and 124 ft above base of formation, National Canyon. B, Shallow channel at base of cliff of 

Manakacha Formation near Mile 23 Rapid in Marble Canyon. C, 

Shallow channel at base of cliff unit of Manakacha Formation, near 

Hualapai Trail to Supai village. D, Twenty-foot deep channel cut in

and siltstone, but includes a very few clasts of chert or 

other durable rocks. The pebbles and cobbles are in thin 

layers on the bottoms and sides of channels and in lenses 

within the channel fill (table J3). In most places the conglomerate does not exceed a few feet in thickness, but near 

Bunker Trail it is 16.5 ft thick and on Kaibab Trail, north, 

it fills a pocket that is 17 ft deep.

In addition to conglomerate, the channel-fill in many 

places includes reddish-brown mudstone or siltstone (at 

Kaibab Trail, north, Topocoba Trail, Havasu Canyon, 

Tuckup Canyon, and other localities) and cross-bedded

jasper-banded limestone at middle of cliff unit of Manakacha Formation; pebble layer in bottom, S B Canyon. E, East half of 8-ft channel 

in silty limestone; channel contains pebbles of reddish-brown 

mudstone and is 107 ft above formation base, Tuckup Canyon. Horizontal and vertical distances in feet.

sandstone (at Topocoba Trail, Kanab Canyon, and Twin 

Springs Canyon).

Whether initial deposition, including the filling of 

channels, was by continental or marine processes is difficult to determine in most parts of the region. In the 

western part of the region where fossiliferous marine 

limestone of the Pakoon occurs as the equivalent of the 

lower part of the Esplanade Sandstone, the probability 

seems great that deposition began with marine sediments. 

The Pakoon Limestone has a basal conglomerate 

equivalent to the Esplanade basal conglomerate to the east.
EROSION SURFACES 165

Erosion

r

i

<

5

L

T^

1 7\1

; : : ;.

il

X

1

_ —

I -±i

_ R^ypuds

r ~~ —

i_Lj__

tone — — .

~tz_ ~r~ —

•"• •'•"•.•:: :'•":

—f ~ —— ~7

-s

I-: =;'• "-"

i 

*" " |

|

D

-200

EXPLANATION 

Sandstone 

Cross-bedded

Calcareous 

Mudstone

Cross-bedded sandy limestone 

Conglomerate 

Limestone 

Jasper 

Siltstone 

Erosion surface

FIGURE H5.—Erosion surfaces in cliff unit of Manakacha Formation, 

Grand Canyon, Ariz. A, Base of cliff unit near Hualapai Trail to Supai 

village. B, Channels near top of cliff unit, National Canyon. C, 30-ft 

deep channel, filled with jasperoid limestone that contains blocks of

Evidence of likely marine deposition is furnished at Guano 

Cave section by concentrations of large pelecypod shells 

among limestone pebbles, and at 1 mi farther east, where 

echinoid spines, crinoid joints, and brachiopods are in 

siltstone and limestone beds directly above the basal conglomerate. In a channel at Hidden Canyon, the basal strata 

of the Pakoon, about 6 ft thick, consist of thin granular 

limestone beds overlain by conglomerate.

The basal conglomerate of the Esplanade Sandstone in 

central and eastern parts of Grand Canyon, in contrast, 

seems to be devoid of fossils and the accumulations of 

uniformly well-rounded gravel furnish no diagnostic 

evidence of depositional environment. Some of the 

reddish-brown mudstone and siltstone that overlies the

jasper and pebbles of dolomite and siltstone, 70 ft above base of formation, S B Canyon. D, At 61 ft above base of cliff unit at Guano 

Cave outcrop section; conglomerate about 6 ft thick at middle right. 

Vertical and horizontal distances in feet.

conglomerate in this region may be of continental 

(fluvial?) origin. Rain pits in shaly siltstone occur about 7 

ft above a channel top at Twin Springs Canyon, and fragments of plant stems were found in basal strata at House 

Rock Rapids (Mile 17.5 in Marble Canyon).

EROSION SURFACES WITHIN 

THE ESPLANADE SANDSTONE

The Esplanade Sandstone in the Grand Canyon region is 

generally composed of two easily recognizable units—a 

lower slope unit and a main cliff unit—but an upper cliffslope unit overlies the cliff unit in some areas. The upper
166 THE SUPAI GROUP OF GRAND CANYON

1

rT^'^ ''' s ^iiefS!^*^?S^-;^Q| i

ygt **^ ,_ fS i ^"f^^8*^?^^*•=• ^ rjf^'^?-^ |

'.< -, , „, i H *v. tv*-* .^ -" •-- ^^ '":*'~:~~-~'**•"_''3% I

^•^—,-•,-:; -^h^r^rir-^^^^r^v - "^^ j

<J r, , ^^-r -VyMT^. « ' Vi-i-^ ' -. I

unit may be subdivided locally into gypsum beds, below, 

and alternating sandstone and siltstone, above.

Whether this upper unit represents local variations in 

sedimentation during essentially continuous deposition, or 

reflects two periods of accumulation and an intervening 

period of erosion, has not been determined.

Evidence of erosion within the Esplanade Sandstone has 

been detected at only two localities; near Bunker Trail in

FIGURE H6.—Erosion surface at top of the Manakacha Formation, at 

the contact of the Manakacha (M) and Wescogame (W) Formations, 

Grand Canyon region, Arizona. A, Channel near Topocoba Trail; 6, 

channel filled with basal conglomerate of the Wescogame, between 

Horsetrail and Waterhole Canyons on the Little Colorado River 

Gorge; C, channel in the Manakacha filled with conglomerate, base 

of Wescogame cliff unit, Fishtail Canyon; D, flat sandstone beds of 

the Wescogame, which fill a shallow swale on the upper surface of 

the Manakacha, S B Canyon; E, east wall of canyon above Supai 

village, channel about 50 ft deep, in slope unit of Manakacha, filled 

with reddish-orange mudstone and scattered pebbles of Wescogame.

eastern Grand Canyon and in Andrus Canyon in the 

northwestern part of the region. At both localities, surfaces containing small channels and exhibiting low relief 

occur in the upper part of the formation.

The erosion surface near Bunker Trail is about 60 ft 

below the top of the Esplanade Sandstone and is readily 

located by an overlying conglomerate of rounded limestone pebbles that fill channels to as much as 3 ft in depth.
50 -*•+•«- 100 70

Wescogame_

White sandstone Wescogame L L White sandstone Wescogame

W^ r^~ IE- 2 5 R —5{^S^^^-

± ^.:v ;.: :- •'.•.•• .-• /: ' : '.:^.

1 Red siltstone _- ^r ^r ; _ ^ia Gray limestone , .1 , Ij

— — — — ~ — "Mann

•'-- A = -=i 25 H?"V

karha *

Esplanade

—T— -. . '-., '-. % . . —— '...' ——•**:——^*——^fr——^——^*^——7^ ——^—T~ 1 '••'.''••-.'' ••'.'' ••••'''••^^i^o^TV"•'•"'-'•"•'•••"' • • Wescogame *

-*- ^'-:^-^'-^-^^^^-^g§Mtg-|^^^sJa15

'Red sandstone. ••''...-•''..•''..••''.••''.•••'

Manakacha 

£

20 -H

[-«- 20 ——»f*-

Manakacha 

40 —————H

en Cnm en

EXPLANATION 

Sandstone

Thick-bedded to massive

Cross-stratified

Flat-laminated 

Shale

^_._T7 Siltstone 

Limestone 

Conglomerate Pebbles Erosion surface

Wescogame 

Formation «^ 13 

(cliff unit)

T

13

i

Manakacha j ^ 

Formation -< 1.2 

(slope unit)

; Sandy, flat-laminated limestone

i^

.=„•. 20 ,..o t£jr7~yi-\_\ '• '•• • \ " 

. __ite friable ••;'-grounded -,''• 'sandstone

•Wescogame

Conglomerate

•Manakacha

FIGURE H7.—Channeled surface at base of the Wescogame Formation, Grand Canyon region, Arizona. A, Tuckup Canyon, north side; B, C, D, Hermit 

Trail, base of cliff unit; E, Little Colorado River Gorge between Horsetrail and Waterhole Canyons; F, Thunder River Trail; C, Toroweap Valley, east side. 

Horizontal and vertical distances in feet.
168 THE SUPAl GROUP OF GRAND CANYON

-co

>: tr

«I

U .-

U

U

E ^

1

-S .!3 42 S

CD «i

TD 

CD 

K

K

8UJB6oOS8/\/\-

CQ

- BlJOB>jBUB|/\|
EROSION SURFACES 169

FIGURE H9. —Unconformable surf ace between the Manakacha(M) and 

Wescogame (W) Formations in Havasu Canyon, Grand Canyon region, Arizona. A, Channel in cross-stratified sandstone of Wescogame 

Formation filled with red-brown mudstone. Apache Trail; 8, channel 

60-ft deep at base of cliff unit of Wescogame, west of Navajo Falls; C, 

irregular erosion surface with amplitude of about 1,000 ft in west side 

of Havasu Canyon near Supai village.

This surface of erosion is at the top of the massive, main 

sandstone cliff and underlies minor cliffs of similar sandstone, alternating with slopes of mudstone. Neither the

conglomerate nor the erosion surface has yet been observed at any other locality in the area.

The erosion surface in the upper Esplanade at Andrus 

Canyon occurs in an area where the formation is unusually 

thick and where a gypsiferous facies and an upper sandstone cliff comprise the upper cliff-slope unit above the 

main sandstone cliff (sec. 24, fig. C8). This intraformational erosion surface is very uneven and contains channels 

about 2 ft deep and 5 or more feet wide. It is located at the 

contact of the gypsiferous facies and the upper sandstone 

cliff. Although the gypsiferous facies extends eastward at 

least as far as Toroweap Valley, the erosion surface at its 

top has been located only at Andrus Canyon, so must be 

considered local.

Neither an erosional surface nor a blanket of conglomerate has been found between the Pakoon Limestone 

and overlying units of the Esplanade Sandstone in any of 

the sections examined in far western Grand Canyon or in 

Iceberg Canyon. Probably the change in depositional environment represented by the limestone and the overlying 

sandstone did not cause a hiatus in the sequence.

EROSION SURFACE 

AT CONTACT OF 

ESPLANADE SANDSTONE 

AND HERMIT SHALE

An exhumed erosion surface at the top of the Esplanade, 

which is beautifully displayed in the walls of Hermit Canyon, consists of numerous depressions or channels carved 

in massive sandstone. The channels are filled with shaly 

mudstone and siltstone of the overlying Hermit Shale. This 

unconformity was the first of several widespread unconformities of erosion to be recognized within red beds of the 

Supai-Hermit sequence. It was discovered in 1916 by Noble (1922, p. 63), and subsequently reported by Schuchert 

(1918, p. 356). Because of this discovery, Noble (1922, p. 

64) redefined the Supai Formation and placed its upper 

contact at the unconformity. He proposed the name Hermit Shale for the shaly mudstones and siltstones above.

A regional extent of considerable magnitude was recognized by Noble (1922, p. 63) for the erosional surface 

because he noted its occurrence below Havasupai Point, 

11 mi northwest of Hermit Trail, and also along Bright 

Angel Trail, 5 mi to the southeast. Continuation of the 

same unconformable surface northwestward to the junction of Kanab Canyon and Hack Canyon was later demonstrated by Gregory and Noble (1923) who reported that 

"the unconformity is coincident with the great bench or 

platform that Dutton has named the 'Esplanade' [suggesting] the possibility that the Esplanade is an exhumed 

surface of Carboniferous time."
170 THE SUPAI GROUP OF GRAND CANYON

Wescogame Black massive sandstone

X Esplanade Sandstone (basal slope unit)

Manakacha

:.. ; - : - -;..". Sandstone with 

• '.,'_• --' "small-scale 

Channel .cross-beds

so

..-• t

30

E §?

TO ~ C 

.^ CD ^

8 Eit

W i- LZ

-<D O O

(slope unit) ^S^Red-brown mudstone '• '"

B

Manakacha 

Formation

Wescogame

Massive sandstone

100

,. . . Massive black sandstone with large-scale cross-bedding WescDgame

Brown-red sandstone, • 

""thin, flat-bedded .--

\ ^Cross-stratified ^_ 

%. red-brown siltstone "

D Massive sandstone

FIGURE H10 (above and right).— Channeled surface at base of the Wescogame Formation in Havasu Canyon, Ariz. A, Near Apache Trail above 

Supai village; B, along Hualapai Trail to Supai village; C, west side of channel exposed in canyon wall east of Supai village; D, in canyon wall opposite C section along Apache Trail; E, at Supai village; F, along Apache Trail near Supai village; C, near Hualapai Trail to Supai village.

The erosional surface at the top of the Esplanade Sandstone forms hills and valleys (table H4, fig. H14) at numerous localities, in addition to those cited by Noble. Many of

these occurrences are described in the measured stratigraphic sections included in this publication. Hills and 

valleys of the erosional surface were observed to the east of
EROSION SURFACES 171

Wescogame 

Formation 

(cliff unit)

Conglomerate 

horizon

Manakacha

Formation

(slope unit)

Massive sandstone

. Mudstcinexv'. -•;.'•••

3-ft JL : ::::::-^ 

channel i ••' •• ' ••

-Wescogame Formation (cliff unit)

Manakacha Formation (slope unit)

EXPLANATION 

Sandstone

Thick-bedded to massive

Cross-stratified

Flat-laminated 

Mudstone 

Siltstone 

Conglomerate 

Erosion surface

-20 

J2-15

-30

Hermit Canyon, at Badger Canyon, near Bunker Trail and 

Kaibab Trail, south, and to the west or northwest of Hermit Trail, at Topocoba Trail, Havasu Canyon, Thunder 

River Trail, National and Tuckup Canyons, Toroweap 

Valley, and Whitmore Wash. Thus, the pre-Hermit channeled and eroded upper surface of the Esplanade extends at 

least from Marble Canyon and the eastern end of Grand

Canyon, westward to Whitmore Wash in middle western 

Grand Canyon.

In many of the areas studied, in which exposures were 

reasonably good, the unconformity is not represented by 

any obvious relief. Massive beds of sandstone in the Esplanade are overlain by shaly siltstone or mudstone of the 

Hermit with an even, flat contact. Principal areas in which 

the upper surface of the Esplanade seems to be planar and 

lacking in either channels or hills, are at Twentynine Mile 

Canyon, Eminence Fault, Blue Spring, Horsetrail Canyon, 

Shinumo, S B Canyon, Blue Mountain Canyon, Prospect 

Valley, and Andrus, Twin Springs, and Snap Canyons. At 

some of these localities, the contact is largely concealed by 

talus and might have very local relief.

In most parts of the region, the post-Esplanade erosion 

surface includes relatively shallow channels which range in 

depth from 10 to 40 ft and have rounded sides and flat bottoms. Typical channels occur at Hermit Canyon (table HI; 

fig. HIS), however, notable exceptions are in two areas 

west of Hermit Trail. Along the Apache Trail (in Havasu 

Canyon) and in National Canyon, the surface includes 

residual mesas of Esplanade-type sandstone, which are 44 

ft and 114 ft, respectively, higher than the generally flat 

upper surface of the Esplanade (fig. HIS). Thus, in these 

areas the amount of truncation in the massive sandstone 

beds at the top of the Esplanade seems to be greater than it 

is in areas to the east or west. Apparently, the postEsplanade upwarping and channeling was greatest in the 

central Grand Canyon area.

The general lack of conglomerate on the erosion surface 

at the Esplanade-Hermit contact is notable. A small lens of 

conglomerate, which consists of rounded limestone pebbles, was found in a channel at Bunker Trail and a sequence of limestone and conglomerate, a few feet thick, 

occurs at a place near Thunder River Trail, but elsewhere it 

is scarce or absent. Possibly the scarcity of conglomerate is 

the result of the hiatus being so short that the Esplanade 

did not become lithified prior to Hermit Shale deposition.

The basal beds of the Hermit Shale generally consist 

of platy or shaly mudstone and siltstone that probably 

were deposited in stream channels and on flood plains, as 

described by White (1929, p. 13). Evidence that this environment of deposition extended across most of the Grand 

Canyon region is furnished by the discovery of land 

plants, especially Walchia, the algal genus Rivularites, rain 

pits, shrinkage cracks, and amphibian trackways in basal 

deposits near Kaibab Trail, south, Hermit Trail, Whitmore 

Wash, and Parashant Canyon.

REFERENCES CITED

Darton, N. H., 1910, A reconnaissance of parts of northwestern New 

Mexico and northern Arizona: U.S. Geological Survey Bulletin 435, 

88 p.
172 THE SUPAI GROUP OF GRAND CANYON 

TABLE H3.— Characteristics of erosion surface at base of the Wescogame Formation, Grand Canyon, Ariz.

[Leaders (—) indicate no data]

Measured section

Thunder River Trail . 

Havasu Canyon ...

National Canyon . . .

S B Canyon ........

Tuckup Canyon ....

Toroweap Valley . . .

Whitmore Wash . . .

Guano Cave .......

Separation Canyon

Channel deptl

None

4ft .......

1ft .......

2-3 ft . . . . .

0.5-1 5 ft .. 

80 ft ......

16ft ......

18ft ......

2-6 ft

20-35 ft . . .

11ft ......

Small-scale

34 ft ......

10ft ......

None

h Channel width

20 ft .....

3-4 ft .....

, do. ..........

15-30 ft ...

20-60 ft ... 

1,400 ft ...

50+ ft ...

800ft .....

50-70 ft ...

20 ft ......

irregularities . . . 

do. ..........

do. ..........

do. ..........

30-40 ft ...

Underlying strata

siltstone.

.......... do. ..........

Thin mudstone on crossstratified sandstone.

Cross-stratified limestone ....

Cross-stratified sandstone ....

.......... do. .........

.......... do. .........

Cross-stratified limestone ....

.......... do. .........

Overlying conglomerate 

distribution

Forms bed and fills channel

below.

tered mud balls and pellets. 

Limestone pellets in mud

matrix. 

Pebbles scattered in

mudstone.

structureless mudstone. 

Fills lower and middle parts of 

channels. 

Scattered pebbles and pellets

along channel sides and 

bottom. 

1-ft bed at bottom and thin

lens at top of sandstone. 

3-ft bed at channel bottom.

Flat-bedded sandstone fill

without gravel. 

Sandstone and siltstone

without gravel. 

Locally fills channel; some

channels contain sand only. 

1-ft gravel bed. 

2-ft gravel bed.

cross-stratified sandstone. 

2-ft gravel bed.

rim. 

No conglomerate; clayey

limestone fill. 

2-ft gravel bed.

Fisher, W. L., 1963, Formation boundaries in the western Grand Canyon area [abs.]: Geological Society of America Special Paper 73, 

p. 153.

Gregory, H. E., and Noble, L. F., 1923, Notes on a geological traverse 

from Mohave, California, to the mouth of San Juan River, Utah: 

American Journal of Science, 5th ser., v. 5, p. 229-238.

McKee, E. D., and Gutschick, R. C, 1969, History of the Redwall Limestone of northern Arizona: Geological Society of America Memoir 

114, 726 p.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

Noble, L. F., 1922, A section of the Paleozoic formations of the Grand 

Canyon at the Bass Trail: U.S. Geological Survey Professional Paper 

131-B, p. 23-73.

FIGURE H11.—Surface of erosion at top of Wescogame Formation and 

base of Esplanade Sandstone: A channel at Twin Springs Canyon, 

Ariz. cut in light-colored cross-stratified sandstone of the Wescogame 

and filled with brown limy sandstone and conglomerate of the Esplanade. The channel is 35 ft deep and 500 ft wide.
EROSION SURFACES 173

-40-

=r~E"SPLANADI

•o°-o o o; o : 0 ,o -0 - o ;o -.0 t o'. c? '.0 .'"'o,

. — . —

-ZE-E?

EXPLAr 

Sandstone

Siltstone 

Mudstone

JATION

1

1 1

• • a'.o'. 

P . ' o -

-^-

Limestone 

Conglomerate 

Erosion surface

— — — — — — — ESPLANADE — — — — — — — — —-

:;.—-•:••..-...—— vyES.COGAME-v,

S.ESPLANADE _

. 0 .O •.«•• Q- ° .

ESPLANADE;/^

HTT~-lir7 Ripple laminae

FIGURE H12.—Channeled surface at top of the Wescogame Formation, overlain by basal conglomerate of the Esplanade Sandstone in 

most places, Grand Canyon, Ariz. A, Mile 17.5, Marble Canyon; 6, 

near Kaibab Trail, south section; C, margin of 240-ft-wide channel,

Bass Trail; D, near Bunker (west Tanner) Trail; and £, Thunder River 

Trail—note angular blocks of limestone conglomerate in channel; F, 

near Hualapai Trail to Supai village. Horizontal and vertical distances in feet.

Schuchert, Charles, 1918, On the Carboniferous of the Grand Canyon 

of Arizona: American Journal of Science, 4th ser., v. 45, p. 347-361.

Steele, G., 1959, Stratigraphic interpretation of the Pennsylvanian-Permian Systems of the eastern Great Basin: Washington University, 

Ph. D. thesis, 294 p.

Welsh, H. E., 1959, Biostratigraphy of the Pennsylvanian and Permian System of southern Nevada: Utah University, Ph. D. thesis, 

106 p.

White, David, 1929, Flora of the Hermit Shale, Grand Canyon, Arizona: 

Carnegie Institution of Washington Publication 405, 221 p.
174 THE SUPAI GROUP OF GRAND CANYON 

—————————————100 ———————————

1*-

1 —— •

r^irr-- __ • __ •— -^S^

t — * — • — • —— • — • —

— — • —— .

•^B^r^,^^' — ESPLANADE_, _._. _ ._. _ .^.__._.

••':-':'-'-:':-^>^=^^

^^^£?\°P t'ol-^^l^^^EE^EEE^E^^

_. — ._._. — ..WESCOGAME—— • — —— — •—• — —————-

B

TO) i

-185

EXPLANATION

Sandstone Erosion surface

FIGURE H13.—Channeled surface at top of Wescogame Formation overlain by Esplanade Sandstone, Grand Canyon region, Arizona. A, 

Section at Andrus Canyon; B, Topocoba Trail to Havasu Canyon; C, Apache Trail to Havasu Canyon; and D, S B Canyon. Horizontal and 

vertical distances in feet.
EROSION SURFACES 

TABLE H4.—Unconformity at top of the Esplanade Sandstone

[Leaders (—) indicate no data]

175

Local relief, in feet

Locality

Bunker Trail ........

Kaibab Trail, south . .

Thunder River Trail . .

National Canyon ....

Toroweap Valley .... 

Whitmore Wash ....

Channel 

depth

70

46 

40 

35

38 

15

Hill 

height

3

44

28 

114 

3

4

Channel 

width

300

100 

75 

60-80 

80-100 

150+ 

400 

1,000

D100

Composition of 

channel fill

Shaly siltstone and conglomerate lens. 

Shaly siltstone ...... . .

. do. ............

Hn

Environmental 

indicators in 

fill

Land plants, rain pits, shrinkage cracks. 

Do.

Limestone with conglomerate bed.

-

do. ............

do. ............ Land plants, borings, Rivularites.

_ ..^^

i „! .. , '. 1 %4 v, T* 5 " 'ill

FIGURE H14.—Unconformable surface between Esplanade Sandstone 

(E) and Hermit Shale (H), Grand Canyon region, Arizona. A, Side of 

channel carved in massive Esplanade Sandstone, filled with shaly 

red-brown mudstone of Hermit Shale, Whitmore Wash; 8, channel at 

top of Esplanade Sandstone, containing shaly mudstone of Hermit 

Shale, Thunder River Trail near Fishtail Canyon; C, mudstone of Hermit Shale filling scour in massive sandstone of Esplanade on Hermit

Trail; D, erosion surface with small hills or mesas between flat areas 

at top of Esplanade covered by Hermit Shale, section on west side of 

Hermit Canyon. Main cliff unit of Esplanade below unconformity is 

250ft thick. Photograph D by E. Tad Nichols.
176 THE SUPAI GROUP OF GRAND CANYON

i

44 Horizon of Hermit 

———————————————— —— ^:::;::^:::::r::::.:v::::,:v.v:;~ ,

, r^v::::::::::::::::::::::"-

—— »i^:"".""."" ———— i —————— • ———— i _______

70 7" ,-r ;. -y Esplanade 

-•;.'. "!.-'..".- (main cliff unit)

^ ::::' : ;-."> D

"- "-. *- ^-

-^DUU ————————————————— J 1 —————————————————————————— ^^"

[L, tKi«*^«l s ———— a 

/ 1 

———— eM^mj^ 

Esplanade 

—

/ / (upper cliff-slope unit)

—————— // ————————— '

:---::.-.-:-.-. . Herrhit' : ^:' v/: A^ 1

Bright-red siltstone "^"^

h« —— 200 —— H

,S|:^- ,. - :-,--, :---- j_ =

A m

E

\V--S.' ,'.>J^x ~--3 ]

.: £splariade>- '" ' '• | IU

1.

T

EXPLANATION 

Sandstone

../'-:; Cross-stratified

— - Mudstone 

-• — Siltstone

" ^ — •' - - - •-•••-••-••• 37.5 fciocnwsS* _ ,

:ffrr. — /"'"•'""• ^?^^ Conglomerate 

•-...- Esplanade •.'.-••• 1 ^~^S* Erosion surface

D ^^K, '_ Herm,t_. _._._.-._._

- — - -^~=*>*-"- " .-'-".-•" . -- ---'---" .. ..--",---',-<

_ . --^^ ••;'•-• ^ • •'"'. • • ..-••; Esplainabei^ ...--;. .--;'. ,-;\.- •_;,

^ in —————————— ^J

100

^g^-rEl-Ehlg rjJlJt '—i^r-^Er j H-75H 

^=--=r =.= --^r— Hermit—

77 -v*^ ///;>'•:•-.;-:-•>•:'• | 

-•- . i'-;-..\^^i«- Esplanade 1 '"-'-i.'>;--^55^:--':--'O--X'-.v

H

h* 400

1 114 :r:z

Conglomerate lens, thickest in center

— Hermit—

^Esplanade-

(-^————————————————————1 ooo————————————————————^n

FIGURE H15.—Erosional unconformity between Hermit Shale and Esplanade Sandstone, Grand Canyon region, Arizona. A, Near Apache Trail, 

east side Havasu Canyon; B, Bunker Trail; C, Kaibab Trail, south section; D, Twin Springs Canyon; f, Thunder River Trail; F, Whitmore Wash; G, 

Hermit Canyon; H, Kanab Canyon; and /, National Canyon. Horizontal and vertical distances in feet.
THE SUPAI GROUP OF GRAND CANYON

TRANSGRESSION AND REGRESSION

Chapter I 

By EDWIN D. McKEE

Contents

Nature of problem

Marine versus continental sediments . . . 

Distribution of environmental indicators 

Formats and unconformities ..........

Insoluble-residue time-trend curves ....

Cyclothems and minor fluctuations ... 

References cited ...................

Page 

179

179

182

183

184

184

186

177
178 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURE II. Distribution of nonmarine fossils and sedimentary structures in Supai Croup and Pakoon

Limestone ... ..... ... 180

12. Comparison of transgression-regression determinations by insoluble residue curves of

Lumsden (1974) and by lithofacies-unconformity measurements of the present study . . 185

Tables

Page

TABLE II. Faunal, floral, and inorganic sedimentary structure indicators of continental environments ................................................................... 181

12. Comparison of formats and unconformities of southeastern Arizona with rock units and

key conglomerate beds of Grand Canyon region ................................... 184
TRANSGRESSION AND REGRESSION 179

NATURE OF PROBLEM

The Grand Canyon embayment during Pennsylvanian 

and Early Permian time was the site of repeated advances 

and retreats of the sea. Following Late Mississippian 

(Chesterian) time, during which transgressive waters from 

a western seaway were restricted to narrow valleys carved 

in the Redwall Limestone and confined to the western part 

of the region (chapter G), successively broader marine incursions left their record in rocks of this region.

The first major advance of the sea, near the beginning of 

Pennsylvanian (Morrowan) time, followed a period of erosion, karst development, and accumulation of a gravel 

blanket, informally referred to as the basal conglomerate 

of the Watahomigi Formation (chapter J). Three subsequent major transgressions occurred (1) during Atokan 

time, as recorded by strata of the upper part of the 

Watahomigi Formation and the Manakacha Formation, (2) 

during Virgilian time as illustrated by the Wescogame Formation, and finally (3) during Early Permian (Wolfcampian) time when the Esplanade Sandstone and Pakoon Limestone were deposited. Each of these four main transgressions was initiated by the development of a regionally 

widespread gravel sheet. They were terminated by regression, followed by subaerial erosion, doubtless the result of 

relative changes in sea level or of regional uplift. In at least 

three of these sequences (Watahomigi, Wescogame, Esplanade-Pakoon) channeled surfaces were produced prior to 

the following major marine incursion.

A wide disparity exists both in the length of time between successive transgressive or regressive sequences in 

the Supai and in the duration of events represented by 

these sequences. The time represented by each major erosional unconformity that is recognized as a formation 

boundary, for example, ranges from a large hiatus between 

the Manakacha and Wescogame Formations that may 

have spanned all of Des Moinesian and Missourian time 

(table C2), to the boundary above, between the Wescogame and Esplanade, which represents only a small time 

interval at the end of Virgilian and perhaps earliest 

Wolfcampian time. Such lack of consistency probably is 

typical of all the unconformities and rock sequences in the 

Supai Group.

Within the limits of these major transgressions and regressions, many minor fluctuations doubtless occurred; 

the lateral extent and the duration of these fluctuations 

were relatively small and the physical records are correspondingly obscure. In the Grand Canyon area, some 

evidence of such events is furnished by "local" erosion surfaces and "scattered" conglomerates preserved in various 

places within both the Manakacha Formation and the Esplanade Sandstone as described in chapter H.

Principal methods applied to the recognition of transgressive and regressive strata consist of the following:

1. Determination of the marine or nonmarine genesis of 

various deposits by fauna, flora, and sedimentary structures, thus demonstrating stages in the advances and retreats of the strandline for a particular locality (fig. II).

2. Ascertaining the boundaries between transgressive and 

regressive sequences by tracing widespread erosion surfaces and (or) key conglomerate beds of regional extent.

3. Recognition within rock sequences of "formats" or thin 

marker-defined units through determination of diagnostic fossils (mostly fusulinids).

4. Construction of curves to record percentages of insoluble residues in systematically collected samples of the 

carbonate rocks in stratigraphic sequences.

5. Analysis and delineation of cyclothems as indicators of 

minor fluctuations in advance and retreat of depositional units as a result of eustatic changes in sea level.

The first and second methods listed above are applied in 

the current study of the Supai in the Grand Canyon embayment. Methods three and four have been used for rocks 

of similar age in adjacent regions to the southeast (Ross, 

1973), and to the west (Lumsden, 1974). Results of their 

studies are compared with those from Grand Canyon. The 

fifth method is considered to have good potential, but has 

not been pursued in detail in this study.

MARINE VERSUS 

CONTINENTAL SEDIMENTS

Alternations of continental and marine sediments 

throughout the Supai Group testify to constant oscillations 

in sea level and (or) to warping of the land surface. The 

assignment of either land or sea environment to a specific 

deposit depends largely on included plants and animals, 

and on associated sedimentary structures considered to be 

diagnostic.

Strata of the Supai that are attributed with reasonable 

certainty to deposition in streams, ponds, or other continental environments consist mostly of shaly red-brown 

siltstones or mudstones (table II). In numerous places such 

strata contain plant assemblages that may include fragments of various seed ferns, the conifer Walchia sp. and 

(or) colonies of blue-green algae known as Rivularites sp. 

Commonly associated with these plants are diagnostic 

sedimentary structures, especially rain pits and shrinkage 

(mud) cracks. Other structures common to this association 

but not restricted to a continental environment, are cusptype ripple marks and convolute laminae. Narrow curving 

tubelike molds with plumose surfaces, considered to be 

probable worm trails (White, 1929, p. 117), are also numerous among continental deposits of the Supai.
180 THE SUPAI GROUP OF GRAND CANYON

EXPLANATION

F Ferns Ri Rivularites

M Shrinkage cracks T Reptile tracks

P Indet. plant sp. W Walchia sp.

Ra Rain pits WT Worm trails

D

FEET 

r 500 -400

-300

-200 

^100

-0

FIGURE 11.—Distribution of nonmarine fossils and sedimentary structures, Supai Group, Grand Canyon region, Arizona. A, Watahomigi Formation; 8, Manakacha Formation; C, Wescogame Formation; D, Esplanade Sandstone. Numbers are those of measured sections (see fig. A1). Tick 

on bar indicates position in section of fossil or structure.

The algal genus Rivularites, represented by small thalli 

or colonies in at least nine localities and at various horizons, is considered by White (1929, p. 43) to have been a 

plant "adapted to survive occasional periods of exposure 

to the air and drying, as is the case with the algae in the 

mud playas of Nevada." A large species of Rivularites in 

the Hermit Shale of Grand Canyon apparently grew in currents of water as shown by strong rippling of associated 

sandy silts and by the "drag deformation" in one direction 

of all protuberances. In some specimens the colony carpet 

seems to have "floated or possibly pulsated in the water" 

(White, 1929, p. 43). Thus, the common impressions of the 

distinctive, horizontally spreading colonies of Rivularites

sp., found in all formations of the Supai Group, are believed to be good evidence of nonmarine deposition.

A second type of organic structure, commonly associated with plant remains of the shaly red-brown siltstones 

in the Supai, is a slender ropelike form, probably a mold, 

that resembles worm trails and borings and is referred to a 

type of "Vermes?" by White (1929, p. 127). This wormlike 

form, as represented in the Hermit Shale, constitutes the 

species Scoyenia gracilis. Specimens from many parts of 

the Supai are similar if not identical, so are considered indicators of a comparable ^ntinental environment. The 

mudstones and siltstones in which they occur probably are 

fluvial deposits.
TRANSGRESSION AND REGRESSION 

TABLE 11.—Faunal, floral, and inorganic sedimentary structure indicators of continental environments

[Leaders (—) indicate no data]

181

Measured Measured 

section section 

No. name

Distance 

above 

base (feet) Evidence

Esplanade Sandstone and Pakoon Limestone1

6. Grandview Trail .....

8. Kaibab Trial, north . . . 

8. ....... do. .......

9. Hermit Trail ........

(2 ) Fossil Bay ...........

17. SB Canyon .........

17. ....... do. .......

18. ....... do. ....... 

19. Blue Mountain 

Canyon 

19. ....... do. .......

25. Twin Springs Canyon .

29. Grand Gulch Mine . . . 

29. ....... do. .......

29. ....... do. .......

....... do. .......

45.0 

17

103 

5

337.5 

86

121 

378 

415.5 

55.5

212

42

51 

27 

125.5 

242

260.5 

295.5

152

Rivularites sp. 

Rivularites sp., Walchia 

sp., rain pits, shrinkage 

cracks. 

Shrinkage cracks. 

Undetermined plants. 

Quadruped tracks. 

Worm trails (Scoyen/a sp.). 

Worm trails (Scoyen/a sp.), 

plants of undetermined 

sp., shrinkage cracks. 

Rivularites sp. 

Worm trails (Scoyen/a sp.). 

Do. 

Rivularites sp., worm 

trails (Scoyen/a sp.). 

Rivularites sp., worm 

trails (Scoyen/a sp.). 

Rain pits. 

Worm trails (Scoyen/a sp.). 

Shrinkage cracks. 

Walchia sp. 

Rivularites sp., shrinkage 

cracks, worm trails 

(Scoyen/a sp.). 

Worm trails (Scoyen/a sp.). 

Walchia sp. 

Quadruped tracks. 

Worm trails (Scoyen/a sp.).

Measured Measured 

section section 

No. name

Distance 

above 

base (feet) Evidence

Wescogame Formation

7. Kaibab Trail, south . . . 

8. Kaibab Trail, north . . . 

7a.(2 ) Bright Angel Trail .... 

9. Hermit Trail ........

20. Prospect Valley ......

25. Twin Springs Canyon .

9.5 Shrinkage cracks. 

18.5 Reptile tracks. 

Do. 

Do. 

Do. 

52.5 Rivularites sp. 

5.5 Rivularites sp., shrinkage 

cracks. 

19.5 Worm trails (Scoyen/a sp.). 

1 52 Walchia sp., plants of 

undetermined sp.

Manakacha Formation

10. Bass Trail ...........

12. Thunder River Trail . . .

23. Parashant Canyon .... 

34. Separation Canyon . . .

179 Plant impressions. 

164 Rivularites, shrinkage 

cracks, rain pits, 

ferns, worm trails 

(Scoyen/a sp.). 

196 Walchia. 

29 Shrinkage cracks, worm 

trails (Scoyen/a sp.).

Watahomigi Formation

7. Kaibab Trail, south . . . 

9. Hermit Trail ........

10. Bass Trail ...........

15. National Canyon ....

Near base 5 species land plants.

120 Walchia, worm trails 

(Scoyen/a sp.). 

115 Rivularites. 

2 Worm trails (Scoyen/a sp.).

2 Not a numbered measured section.

Strata of definite marine origin in the Supai Group include virtually all types of limestone and dolostone. This 

contention of origin in the sea is supported by inclusion 

within these strata of a large array of invertebrate fossils, 

representing 14 major groups, that are generally believed 

to have inhabited marine environments; some, however, 

may also have dwelt in brackish waters. Scattered hard 

parts, consisting of the teeth and bones, of sharks and 

other vertebrate marine animals also occur in the carbonate rocks. Finally, evidence of marine habitat is furnished by an abundance of the marine alga known as 

Osagia sp. that forms grain coatings in various localities. 

The marine plants and animals are, in general, most abundant in western parts of the formations in the Supai 

Group, but there are exceptions. The distribution pattern 

supports the contention that normal marine waters not 

only entered the Grand Canyon embayment largely from 

the Cordilleran seaway in Nevada, but also locally 

through connections to the northeast or southeast.

Between lithologic facies extremes of the Supai, represented at one end by red-brown shaly siltstones and mudstones that are largely or entirely continental, and at the 

other end by various types of marine limestones and dolostones, are the abundant, uniformly very fine grained, 

cross-stratified sandstones that contain both continental 

and marine fossils and sedimentary structures. At places, 

the sandstones contain the well-preserved footprints of 

land-dwelling quadrupeds; elsewhere these sandstones incorporate the tests of foraminifers or the skeletal fragments 

from shells of various marine animals.

Based on faunal distribution within the various sandstone bodies and their geographic and stratigraphic positions with regard to bodies of both mudstone and carbonate rocks, deposition of the sandstone beds must have 

been controlled by a shallow-water, nearshore environment. In brief, the sandstones probably represent transitional stages of depositional cycles with features characteristic of both continental and marine environments.
182 THE SUPAI GROUP OF GRAND CANYON

DISTRIBUTION OF 

ENVIRONMENTAL 

INDICATORS

A synthesis of the paleoenvironmental evidence based 

on characteristic animals, plants, and sedimentary structures from each unit and formation of the Supai Group 

follows. Where these fossils and structures are considered 

diagnostic of either a continental or a marine environment, 

their value in determining the stage of advance or retreat of 

the sea at a particular time is considerable.

The three units of the Watahomigi Formation (fig. P6) 

all contain marine fossils, including brachiopods, 

molluscs, trilobites, and foraminifers. The greatest concentrations of these fossils, however, are in the middle cliff 

unit, which is largely carbonate rock. This unit probably 

represents the maximum advance during the first major 

transgression of Supai time.

The lower slope unit of the Watahomigi, which contains 

some limestone, but consists largely of red mudstone and 

siltstone, probably represents early stages of the first transgression because marine invertebrates of several types occur in scattered limestone beds throughout its western or 

seaward parts, and foraminifers are recorded as far east 

as Grandview Trail. Some brachiopods occur even among 

pebbles in the basal conglomerate of the Watahomigi at 

localities in western Grand Canyon. Continental fossils are 

sparse, but five species of land plants are recorded (White, 

1929, p. 10) from the lower red siltstones near the Kaibab 

Trail, south, and sedimentary structures, including rain 

pits and shrinkage cracks, are reported from basal strata 

near Hermit Trail (Schuchert, 1918, p. 357).

The upper slope unit of the Watahomigi (fig. P6), like 

the bottom unit, contains much red siltstone, but, especially in the west, also includes numerous beds of carbonate rock. This unit is of Atokan age and begins with a basal 

conglomerate, so it probably represents an early stage of 

the second major transgression. Because no land fossils or 

structures have been found associated with this basal conglomerate of Atokan age, and no marked evidence of 

channeling underlies it, the Grand Canyon region was 

probably not above sea level when deposition began. 

Thus, Atokan sediments of this embayment likely started 

to accumulate in a marine environment. Marine fossils including brachiopods, trilobites, and pelecypods are recorded from some of the western sections and foraminifers 

from as far east as Grandview Trail.

The cliff unit of the Manakacha probably represents the 

time of maximum marine advance during the second major 

transgression of the region. Marine fossils have been found 

at various horizons at nine localities including four in

eastern Grand Canyon (fig. E8). Seven groups of invertebrate animals are represented, but most numerous by far 

are foraminifers including five genera of fusulinids (fig. 

ElO). At this time (Atokan), the transgressing sea advanced northeastward through the Black Mesa sag to connect with the Paradox basin as indicated by isopach lines 

(fig. D4).

The overlying slope unit of the Manakacha includes 

much red siltstone and mudstone, in addition to limestone, 

especially in the eastern Grand Canyon region (fig. P8), 

and this is interpreted as the result of regression with a 

large increase of detrital sediment. The biota of this unit 

contains a few marine forms, especially fusulinids (fig. 

Ell), but also such land plants as Walchia sp., various species of indeterminate ferns and Rivularites sp., in scattered 

localities of central Grand Canyon (fig. E24).

The Wescogame Formation begins with a sheet of conglomerate, but unlike the two widespread conglomerates 

below, it probably represents a continental environment 

and it overlies a much channeled erosion surface that apparently resulted from being elevated above sea level. A 

few marine fossils occur near the base in far western sections (fig. E13), but continental plants and structures occur 

at various localities farther east. Shrinkage cracks at Snap 

Canyon, Walchia sp. at Parashant Canyon, and Rivularites sp. in Havasu Canyon, all near the formation base, 

testify to a continental environment during initial stages of 

deposition. Fossils higher in the cliff unit of the 

Wescogame are, in general, scarce, and consist largely of 

fusulinids and other foraminifers (fig. E15). At several localities in eastern Grand Canyon, in contrast, the wellpreserved tracks of quadrupeds, possibly amphibians, occur on the surfaces of dipping cross-strata (figs. E21, E22). 

The character and relative scarcity of the Wescogame 

fauna probably reflects a depositional environment unfavorable to life. The environment is dominated by much 

very fine, even-grained, quartz sand and is cross-stratified 

throughout.

The overlying slope unit of the Wescogame seems clearly 

to represent a regressive stage, following the third major 

transgression. Like other regressive deposits of the Supai 

Group, it contains much red mudstone and siltstone and includes some characteristic land plants. Such plants, associated with shrinkage cracks and rain pits, have been 

recorded at this horizon near Hermit Trail (table E3) and in 

Iceberg Canyon where they occur in association with cusptype ripples.

The Esplanade Sandstone and its western equivalent, the 

Pakoon Limestone (McNair, 1951) (fig. P12), constitute 

the record of a fourth and still younger major transgression 

and regression within the Supai Group. The record begins 

with a widespread erosional surface including channels of
TRANSGRESSION AND REGRESSION 183

30- to 40-foot depth similar to those underlying the subjacent Wescogame. The erosion surface indicates a relative 

change in sea level sufficient to permit fluvial downcutting 

and it marks the end of a transgressive-regressive cycle. A 

broad but thin conglomerate layer overlying the surface 

constitutes the beginning of the next transgressive stage. 

This conglomerate, which fills many channels, probably is 

nonmarine, like the basal conglomerate of the Wescogame.

The basal slope unit of both the Esplanade and Pakoon 

consists largely of shaly red mudstone and siltstone, and 

resembles most of the older regressive units of the Supai 

Group. Furthermore, it likewise contains many of the 

fossils and structures characteristic of continental deposits 

found elsewhere. These include the plants Walchia sp., 

Rivularites sp., and others, the worm trails called Scoyenia 

sp., and such surface structures as shrinkage cracks, rain 

pits, and cusp ripple marks (table II). These indicators of a 

continental environment occur at many localities from 

eastern Grand Canyon westward to Iceberg Canyon. Only 

at Hidden Canyon and Whitmore Wash have marine indicators, represented by foraminifers, been found in this 

unit.

The cliff unit of the Pakoon Limestone that occurs on the 

western edge of the Grand Canyon embayment is composed mostly of carbonate rocks and contains many forms 

of marine animals that serve to document the environment. These fossils consist of corals, bryozoans, 

gastropods, sharks teeth, and fusulinids (figs. E17, E18).

The eastward lateral equivalent of the Pakoon cliff unit, 

at least in part, is the lower part of the main cliff unit of the 

Esplanade. The transition from the facies of one formation 

to the other apparently is within a very short distance, 

because only a few relatively thin tongues of limestone extend far eastward into the Esplanade. Most of the main 

cliff unit of the Esplanade consists of fine cross-stratified 

sandstone in which fossils are sparse and poorly preserved. 

These fossils consist largely of two types: (1) the comminuted clasts of marine invertebrates, which occur in 

numerous sections as far east as Hermit Trail and House 

Rock Canyon (fig. E16); and (2) the uncommon tests of fusulinids that have been found at Twin Springs and S B 

Canyons, and at Whitmore Wash (fig. E18), but not in any 

eastern sections.

In the upper cliff slope unit of the Esplanade, evidence 

is recorded of a final regression within the Supai Group. 

Not only do the slopes contain much red siltstone and 

mudstone, but also, in numerous places, they contain 

indicators in the form of continental-type fossils and structures. At Tuckup Canyon occur two zones of worm trails 

(Scoyenia sp.); at Snap Canyon, beds containing Walchia 

sp. and shrinkage cracks; at Hidden Canyon, Walchia sp.; 

and at Pigeon Wash, Scoyenia sp., ripple marks, shrinkage

cracks, and Walchia sp. (table II). Thus, the youngest deposits of the Esplanade Sandstone are continental.

FORMATS AND 

UNCONFORMITIES

The term "format" as proposed by Forgotson (1957) for 

marker-defined, vertically segregated rock units was applied by Ross (1973, p. 893) in subdividing thick lithologic 

units of Pennsylvanian and Lower Permian strata in southeastern and central Arizona. Although the term has no formal status with the American Commission on Stratigraphic Nomenclature, Ross considered it a useful unit for 

local correlation. He used unconformities that "commonly 

are marked by thin conglomeratic beds, red siltstone or 

sandstone, or well-sorted, shallow water calcarenites," to 

separate the strata under study in that region. He recognized 15 unconformities, on the basis of which he subdivided the rocks into 14 formats which were designated by 

the letters A-N (table 12).

An attempt to correlate the unconformities and formats 

listed by Ross for central Arizona with corresponding features in the Grand Canyon region is shown in table 12. The 

five key conglomerate beds and underlying erosion surfaces in the Grand Canyon area seem to match unconformities 1, 2, 10, 13, and 15 of central Arizona (Mogollon 

Rim), assuming age determinations based on fusulinids 

(table E4) are correct in both areas. This correlation suggests that formats A, B, J, M, and N described by Ross are 

represented in strata of the Supai Group and that formats 

C-I and unconformities 3-9 of central Arizona probably 

are missing in the Grand Canyon region, because no fossils 

of unequivocal Des Moinesian age or of Missourian age 

have been recorded there. Sufficient information on the 

age of the Wescogame is not available to determine 

whether formats J, K, or L, or all three, are represented in 

it. No indication of an unconformity above the basal conglomerate of the Wescogame has been recorded from that 

formation.

Because of the relatively weak correlations of minor unconformities within the Pennsylvanian and Lower Permian 

strata between central Arizona and the Grand Canyon 

region, formats have not proven useful in this study involving the recognition of transgressive and regressive 

units. Times of advance and retreat of the sea during middle parts of the Pennsylvanian (Des Moinesian? and Missourian time) are unrecorded because of nondeposition; 

however, in both upper and lower parts of the Supai major 

advances and retreats are already well established on the 

basis of lithology, widespread erosion surfaces, and other 

features previously discussed.
184 THE SUPAI GROUP OF GRAND CANYON

TABLE 12.—Comparison of formats and unconformities of southeastern Arizona with rock units and key conglomerate beds of Pennsylvanian to

Permian age in Grand Canyon region

Subdivisions in southeastern Arizona 

(modified from Ross, 1973, p. 888)

Unconformity

15

13

11

10

8

3

2

1

Format

M, N

K, L

J

H, I

C-G

B

A

Formation

Supai

Earp

Horquilla

Horquilla

Horquilla

Horquilla

Black Prince

Escabrosa

Age

Wolfcampian

Virgilian

Virgilian

Missourian

Des Moinesian

Derryan

Morrowan

Mississippian

Subdivisions of Grand Canyon 

in the present study

Key conglomerate bed

Basal conglomerate

Basal conglomerate

Basal conglomerate

Atokan conglomerate2

Basal conglomerate

Formation

Hermit

Esplanade and Pakoon 1

Wescogame(?)

Wescogame(?)

Not recognized

Not recognized

Watahomigi-Manakacha

Watahomigi

Redwall

Conglomerate at base ot Atokan-age rocks.

INSOLUBLE-RESIDUE 

TIME-TREND CURVES

Based on the thesis that the amount of insoluble residue 

in carbonate rocks should increase shoreward or toward 

the supposed source, time-trend curves were prepared by 

Lumsden (1974, fig. 1) for a series of sections of Permian 

and Pennsylvanian strata in southern Nevada. The 500 

specimens studied "were dominantly fine-sand to silt size, 

angular quartz with variable minor quantities of fine 

brown to reddish clay." All samples containing visible 

authigenic chert were eliminated and not processed.

The time-trend curve of Lumsden for the Iceberg Canyon measured section is reproduced on the left side of 

figure 12. It shows four tongues (or times) of major increase 

in insoluble-residue content and these are interpreted as 

being times of major regression. Using the same vertical 

scale, the Iceberg Canyon measured section of the present 

study and two others located eastward in the Grand Canyon embayment, have been plotted to show zones of transgression and regression determined on the basis of lithology and unconformities. In the eastern sections, facies 

consist of far more detrital rock than in equivalent units in 

Iceberg Canyon where most of the rock is carbonate.

Measured sections at Iceberg Canyon, Pigeon Wash, 

and Parashant Canyon show zones of regressive-type sediment at five levels (fig. Rl). The ultimate plane of regression, where the trend in strandline movement reverses and 

transgression begins, is commonly marked by a surface of 

erosion, a blanket of conglomerate, or both. Such markers

within the Supai Group occur within stratigraphic units 

that consist largely of red shaly beds of siltstone and mudstone, and may contain the imprints of land plants and 

subaerial structures such as rain pits and shrinkage cracks.

CYCLOTHEMS AND 

MINOR FLUCTUATIONS

Cyclothems constitute one of the most characteristic and 

distinctive features of the Pennsylvanian System in many 

parts of the world. The term "cyclothem," as used by 

Weller (1930, p. 99) for rock sequences of Pennsylvanian 

age in the eastern and central United States, implies "recurrence, repetition, or a return to the starting point," in contrast to the term "rhythm," which has a time connotation 

for recurring events or deposits.

The nature of cyclothems and attempts to interpret their 

genesis have been the basis of a voluminous literature. 

Principal concepts explaining their origin are the 

diastrophic control theory of Weller (1930, 1931, 1956) 

and the glacial control theory of Wanless and Shepard 

(1936). Both diastrophism and glacial cycles are causes of 

eustatic shifts in sea level. Where the floor of the sea has 

been alternately above and below wave base, the principle 

of base-level control has been invoked as a mechanism to 

explain the frequent repetition of similar depositional sequences (Wanless, 1950, p. 25; Wheeler and Murray, 

1957).

Complete cyclothems, as described from the midcontinent region, commonly consist of eight rock units or
TRANSGRESSION AND REGRESSION 185

Iceberg Canyon 

(Lumsden, 1974)

WEST

Iceberg 

Canyon

FEET

1000

900

800

700

600

500

400

300

200

100

50

0

EAST

0 10 20 30 40 50 60 70 80 90 100 

PERCENT INSOLUBLE RESIDUE

lMcNair(1951)

EXPLANATION

Sandstone 

Limestone 

Siltstone

Mudstone or claystone 

Conglomerate 

Gypsum 

'Erosion surface

layers—the lower four being continental, the upper four 

marine (Weller, 1930, p. 101). In each cyclothem two relative changes in sea level are recognized: one was a sinking 

that terminated continental deposition and caused marine 

transgression; the other ended marine deposition by uplift 

and initiated erosion. Each cyclothem has been considered 

a formation (Weller, 1930, p. 101) with an erosion surface 

separating it from the superjacent formation.

Cyclic sedimentation similar to that in the midcontinent 

is represented throughout large areas in southwestern 

United States (Wanless and Patterson, 1951, p. 662). In 

places, much of this deposition was remote from areas of 

diastrophic activity. The inference is made, therefore, that 

variations in depth resulted from eustatic sea-level changes 

during Pennsylvanian and Early Permian time (Wanless 

and Patterson, 1951, p. 655).

In the Supai Group of western Grand Canyon, the presence of cyclothems was noted long ago (McKee, 1937,

FIGURE 12.—Comparison of transgression-regression determinations by 

insoluble-residue curves of Lumsden (1974) and by lithofacies-unconformity measurements of the present study, western Grand Canyon, 

Ariz.

p. 341) where a typical cycle was described as consisting of 

"(1) red beds; (2) cross-laminated sandy limestones; (3) 

flat-bedded, sandy limestones; (4) crystalline, fossiliferous 

limestones; (5) flat-bedded, sandy limestones; (6) crosslaminated, sandy limestones; (7) red beds." The following 

are locations where later observations have been made on 

cyclothems in the Supai and in formations of similar age in 

adjoining regions: numerous sections in southern Arizona 

(Wanless and Patterson, 1951); mechanically deposited 

Pennsylvanian limestones of northeastern Nevada (Dott, 

1958); and southern Nevada sections directly west of 

Grand Canyon (Lumsden, Ledbetter, and Smith, 1973, 

p. 663).

In the present investigation of the Supai Group, no 

systematic study of its cyclothems was made, largely 

because time did not permit, but cyclothems were observed to be well developed in the carbonate rocks of the 

Wescogame Formation and, to a lesser extent, in the
186 THE SUPAI GROUP OF GRAND CANYON

Manakacha of western Grand Canyon. They are conspicuous, especially in sections along the Grand Wash 

Cliffs and at Iceberg Canyon, where they weather with a 

characteristic step-like or cliff-slope topography.

In central and eastern Grand Canyon, where limestone 

is less abundant than in the west and where sandstone is 

progressively more common, repeated alternations of cliffforming sandstone and slope-forming mudstone or siltstone may be landward equivalents of dominantly limestone cyclothems farther from shore. In any event, these 

alternating sequences seem to represent fluctuations in 

areas of deposition resulting from minor advances and 

retreats of the sea within the limits of the major transgressions and regressions as determined by key conglomerate 

beds and widespread erosion surfaces.

REFERENCES CITED

Dott, R. H., Jr., 1958, Cyclic patterns in mechanically deposited Pennsylvanian limestones of northeastern Nevada: Journal of Sedimentary 

Petrology, v. 28, no. 1, p. 3-14.

Forgotson, J. M., Jr., 1957, Nature, usage, and definition of markerdefined vertically segregated rock units: American Association of 

Petroleum Geologists Bulletin, v. 41, no. 9, p. 2108-2113.

Lumsden, D. N., 1974, Relationships among insoluble residue, dolostone 

and limestone facies: Journal of Sedimentary Petrology, v. 44, no. 2, 

p. 450-455.

Lumsden, D. N., Ledbetter, M. T., and Smith, G. T., 1973, Lithostratigraphic analysis of the Bird Spring-Callville Group and Pakoon Formation (Pennsylvanian-lower Permian), southern Clark County, 

Nevada: Journal of Sedimentary Petrology, v. 43, no. 3, p. 655-671.

McKee, E. D., 1937, Researches on Paleozoic stratigraphy in western 

Grand Canyon: Carnegie Institution of Washington Year Book 36 

for 1936-1937, p. 340-341.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

Ross, C. A., 1973, Pennsylvanian and Early Permian depositional history, southeastern Arizona: American Association of Petroleum 

Geologists Bulletin, v. 57, no. 5, p. 887-912.

Schuchert, Charles, 1918, On the Carboniferous of the Grand Canyon 

of Arizona: American Journal of Science, 4th ser., v. 45, no. 267, 

p. 347-361.

Wanless, H. R., 1950, Late Paleozoic cycles of sedimentation in the 

United States: International Geologic Congress, 18th, Great Britain, 

1948, Report, pt. 4, p. 17-28.

Wanless, H. R., and Patterson, J., 1952, Cyclic sedimentation in the 

marine Pennsylvanian of the southwestern United States: Cong. Av. 

Etudes de Stratigraphie et de Geologic du Carbonifere, 3d, Heerlen, 

June 25-30, 1951, compte rendu, v. 2, p. 655-664.

Wanless, H. R., and Shepard, F. P., 1936, Sea level and climatic changes 

related to late Paleozoic cycles: Geological Society of America Bulletin, v. 47, no. 8, p. 1177-1206.

Weller, J. M., 1930, Cyclical sedimentation of the Pennsylvanian period 

and its significance: Journal of Geology, v. 38, no. 2, p. 97-135.

____1931, Sedimentary cycles in the Pennsylvanian strata—A reply: 

American Journal of Science, 5th ser., v. 21, p. 311-320.

____1956, Argument for diastrophic control of late Paleozoic cyclothems: American Association of Petroleum Geologists Bulletin, v.

40, no. 1, p. 17-50. 

Wheeler, H. E., and Murray, H. H., 1957, Base-level control patterns in

cyclothemic sedimentation: American Association of Petroleum

Geologists Bulletin, v. 41, no. 9, p. 1985-2011. 

White, David, 1929, Flora of the Hermit Shale, Grand Canyon, Arizona:

Carnegie Institution of Washington Publication 405, 221 p.
THE SUPAI GROUP OF GRAND CANYON

CONGLOMERATES

Chapter J 

By EDWIN D. McKEE

Contents

Introduction ..............................................

Conglomerates of the Watahomigi Formation ..........,,...,,,..,

Atokan conglomerate . ..................

Wescogame basal conglomerate .......... .... .......

Basal conglomerate of the Esplanade Sandstone and Pakoon Limestone 

Erosional surface at base of the Hermit Shale .......

Intraformational conglomerates in the Hermit Shale . .........

References cited ............................................

Page

189

189

190

193

194

202

203

203

187
188 THE SUPAI GROUP OF GRAND CANYON

Illustrations

FIGURE J1. Photographs of Watahomigi conglomerates .......... ............................ 190

J2. Photographs of Atokan conglomerate ............ ........ .............. 194

J3. Photographs of Wescogame basal conglomerate ....... ..... .................. 196

J4. Sketches showing channel forms and composition in the Esplanade . ................ 197

J5. Photographs of Esplanade conglomerate .............. ..... ..... ............... 200

Tables

Page

TABLE J1. Occurrence, composition, and physical properties of Atokan conglomerate .............. 192

J2. Occurrence, composition, and physical properties of Wescogame basal conglomerate ..... 192

J3. Characteristics of Esplanade Sandstone and Pakoon Limestone basal conglomerate and

underlying erosion surfaces .............. ................... ............ 198

J4. Characteristics of the surface of relief at the base of the Hermit Shale .................... 202

J5. Stratigraphic position of buried channels and local conglomerates above base of Hermit

Shale ...................................................................... 203
CONGLOMERATES 189

INTRODUCTION

Four widespread thin conglomerate beds have been 

recognized throughout most of the Grand Canyon region 

and serve as key beds in tracing the boundaries of 

lithologic units (fig. HI). The conglomerates occur as 

sheet-like or blanket deposits, for the most part, but in 

places they either completely or partly fill channels or 

depressions in the underlying strata so that locally they 

may attain considerable thickness.

The four conglomerate beds are believed to mark the 

positions of unconformities. Three of them form the basal 

deposits of formations—the Watahomigi and Wescogame 

Formations, and the Esplanade Sandstone or its western 

equivalent, the Pakoon Limestone (McNair, 1951); the 

fourth conglomerate separates strata of Morrowan and 

Atokan ages, as indicated by fossils above and below 

(chapter E) and is informally referred to as the Atokan conglomerate. Unlike the other three conglomerates, it rests 

on an even surface that seems to be virtually undissected 

and without local relief.

Traces of a few conglomeratic units other than those 

already referred to have been noted within the formations 

of the Supai Group in various stratigraphic sections, but 

must be considered to be of limited extent and of local 

origin on the basis of information presently available. On 

the other hand, a surface of widespread channeling at the 

top of the Esplanade Sandstone is not associated with any 

conglomerate although it apparently indicates a break in 

sedimentation.

Each of the four key conglomerate beds in the Supai 

Group is composed of gravels having distinctive properties 

of composition and degrees of roundness. These features 

probably have resulted from differences in source material 

and perhaps also from differences in distance and method 

of transport. They make possible a recognition of specimens from the various conglomerate units with a fair 

degree of accuracy.

CONGLOMERATES OF THE 

WATAHOMICI FORMATION

A distinctive type of conglomerate occurs in scattered 

lenses at or near the base of the lower slope unit of the 

Watahomigi at many places in the walls of Grand Canyon 

(figs. A2-A8). In 12 of the localities studied, it was at the 

base of the section and at 5 others, it was less than 15 ft 

above. In this respect it might be considered a normal basal 

conglomerate; however, it is not a single continuous bed or 

unit of conglomerate, but, rather, a large number of separate and independent deposits of gravel ranging from 1 to 

12 ft in thickness and forming a zone within the oldest

mudstone and limestone accumulations of the formation 

(table Hi). In one measured section at Havasu Canyon, six 

thin but distinct conglomerate units were recorded in a 

single traverse of the basal 100 ft; at Whitmore Wash, to 

the northwest, three were noted, and at National Canyon, 

two.

Gravels forming conglomerates in the basal slope unit of 

the Watahomigi are composed largely of hard, durable 

rocks, by far the most common of which is chert in a variety of colors including white, pink, light gray, dark gray, 

yellow, and reddish brown. Pebbles of smoky quartz and 

yellow quartz are numerous at some localities, but siltstone pebbles are uncommon and both mudstone and gray 

limestone pebbles are rare. The matrix for the pebbles is 

mostly fine-grained sandstone or siltstone, but locally it is 

reddish-brown mudstone and, in one bed at Whitmore 

Wash, it is clastic limestone. In general, these conglomerates are dark brown or gray, especially on the weathered 

surfaces, either because most of the pebbles are dark or 

because of iron-pigmented cement, or from a combination 

of matrix and cement.

In most localities the majority of gravels range between 

0.25 and 0.75 in. in diameter, but some much larger particles occur in many beds. Maximum sizes observed include a cobble of 12 in. diameter at National Canyon, one 

of 8 in. at Havasu Canyon, and one of 6 in. at both S B and 

Parashant Canyons. Most of the cobbles and pebbles have 

high sphericity, probably because of the common spherical 

shape and uniformity of the rock types from which they 

were derived. No conspicuous orientation was recognized 

in any of these deposits.

Most of the gravels, formed of durable, resistant rock 

such as chert, are angular to subangular (fig. Jl). Only in 

the Blue Mountain Canyon and Whitmore Wash sections 

are subrounded pebbles of resistant materials present in 

some abundance. On the other hand, at Andrus Canyon, 

Twin Springs Canyon, and Whitmore Wash, pebbles of 

limestone are numerous and these are mostly subrounded 

or rounded.

The conglomerates of the basal slope unit in the Watahomigi clearly are marine. At seven localities, brachiopods 

and other fossils considered characteristic of the sea occurred scattered among the gravels. One fossil of very 

common occurrence is a small, nearly spherical Composite 

(fig. JIB, E), which at Havasu Canyon, and probably elsewhere, had been rolled around on the sea floor with quartz 

pebbles of about the same size, and finally was buried with 

random orientation among fine sand grains that formed a 

matrix. Elsewhere, brachiopods such as Derbyia and Anthrocospirifer of more delicate shell structure and ornamentation, but showing few signs of abrasion or breakage, 

are also preserved in conglomeratic beds. These fossils apparently lived and were buried among the gravels without 

appreciable washing about by waves.
190 THE SUPAI GROUP OF GRAND CANYON

FIGURE J1 (above and facing page).—Basal conglomerate of Watahomigi, which is at or near the base of the lower slope unit, consists 

mainly of angular to subangular pebbles of flint and chert. A, Base of 

Watahomigi Formation, east side of Toroweap Valley; 6, 13 ft above

base of formation, includes Spirifer and Compos/ta among highly 

polished pebbles at Whitmore Wash; C, 11 ft above base of formation, siltstone and limestone clasts, Eminence Fault; D, 5 ft above 

base of formation, fossil-bearing conglomerate, dominantly white 

chert, some large and subangular clasts at National Canyon; E, base 

of Watahomigi, contains scattered chert pebbles and worn specimens 

of Compos/ta, Havasu Canyon; F, base of formation, north of Hindu 

Canyon; C, basal conglomerate near Navajo Falls, Havasu Canyon. 

Scale in inches.

Evidence that the basal Watahomigi conglomerates were 

derived from a relatively close source is the comparatively 

small amount of rounding on most pebbles. Surfaces characteristic of strong attrition through rolling by wave action 

are absent on most specimens; the dominantly chert composition may be attributed to derivation from the underlying Redwall Limestone of Mississippian age. The source 

of other less-common rock types is not readily apparent, 

but the friable sandstone and siltstone gravels could not 

have been transported far. Metamorphic and igneous rock 

types are lacking.

The age of these conglomerates, determined on the 

basis of fossils associated with the gravels and of interbedded fossils, is Early Pennsylvanian or Morrowan. 

Perhaps the most diagnostic forms are brachiopods of the 

genera Anthrocospirifer, Punctospirifer, and Linoproductus, found at 15, 3, and 7 localities, respectively (fig. El), 

and considered most likely to be of Early Pennsylvanian 

age. Anthrocospirifer occidentalis, also believed of Morrowan age, has been found associated with the conglomerates at Snap Canyon and Guano Cave sections. The 

upper limit of conglomerates of Morrowan age is not certain, but fossil evidence suggests that at least the lowest 40 

ft of section and possibly more is Early Pennsylvanian. In 

some places conglomerate units resembling those at or near 

the base occur 100 ft or more above the base.

ATOKAN CONGLOMERATE

A conglomerate bed in the upper part of the Watahomigi 

Formation that probably marks a regional unconformity 

has been recognized in about one-third of the stratigraphic 

sections studied in Grand Canyon. It occurs near the top of 

or slightly above the wedge of cliff-forming limestone that 

constitutes the middle unit of the formation and is known 

as the Atokan conglomerate. From the eastern end to the 

western end of Grand Canyon, the Atokan conglomerate
CONGLOMERATES 191

is progressively higher, ranging from about 65 to 150 ft 

above the base. This increase is roughly in proportion to 

an increase in thickness of the formation, and reaches a 

maximum in extreme western Grand Canyon where the 

limestone wedge is thickest. Abnormally thin sections 

below the Atokan conglomerate at Snap Canyon and 

Pigeon Wash in the west are believed to result from a topographic high in that area on the underlying Redwall 

surface.

The basal Atokan conglomerate occurs laostly as a relatively even bed having a thickness that ranges from place 

to place between about 1 and 10 ft (table Jl). Channel fills 

are not a common feature as they are with most other conglomerates of the Supai. The surface on which deposition 

occurred apparently was rather flat and even, and marine 

fossils, mostly brachiopods, have been found in closely 

associated beds at Toroweap Valley and at Pigeon Wash.

In most localities, the pebbles and granules that are contained in this conglomerate are composed largely of white 

to gray or buff chert and dark reddish-brown jasper, but at 

some localities reddish-brown siltstone, gray limestone, or 

both are associated, and in one place, Thunder River Trail, 

milky quartz is included. Particles of durable rock types 

such as chert and jasper are largely angular to subangular 

but many of the softer rock types, especially the limestones, are subrounded or rounded. At three measured sections—Havasu Canyon, Blue Spring, and Guano Cave— 

only limestone pebbles occur, suggesting that these gravel 

lenses possibly do not actually represent part of a regional 

erosion surface, but were developed locally following 

deposition of the limestone strata.

The generally angular to subangular pebbles and granules are mostly 0.25-0.5 in. in long dimension, and commonly are scattered with random orientation through a 

fine matrix. In places, however, as at S B Canyon (fig. 

]2A), they are tightly packed together and in contact, one 

with another; elsewhere, as at Whitmore Wash (fig. J2F), 

they form horizontal, flat beds of contrasting textures and 

most of the tabular grains are oriented with long axes 

parallel to the bedding. Maximum pebble sizes noted were 

at Toroweap Valley, National Canyon, and S B Canyon 

where diameters of 3 and 4 in. occur.

Despite the wide variety of colors represented in individual clasts and in matrix materials that range from the gray 

of clastic limestones to a rusty brown in most siltstones, 

the overall appearance of the conglomerate in a majority 

of places is that of a very dark brown ledge, locally 

yellowish or grayish, but mostly reddish brown.

Interpretation of the Atokan conglomerate of the 

Watahomigi is based largely on two features—the thin 

predominantly sheetlike form of the gravel body and a 

stratigraphic position in some localities directly below 

fossil-bearing strata of the same rock sequence. The 

detrital fragments probably were accumulated on a sea 

floor with a flat, even surface, but the pebble shapes indicate that they were not rolled about greatly, nor 

transported far. All of the rocks represented by the clasts 

seem to be of types that occur in underlying parts of the 

Watahomigi Formation, apparently resulting from local 

erosion and consequent deposition on the floor of an advancing sea.

The age of the conglomerate is considered Atokan on the 

basis of the erosion surface between it and the underlying
TABLE J1.—Occurrence, composition, and physical properties of pebbles and cobbles of the Atokan conglomerate

[Leaders (-») indicate data lacking] K)

Measured section 1

Name

Kaibab Trail, north . 

Thunder River Trail 

Havasu Canyon . . . 

National Canyon . .

Tuckup Canyon . . . Toroweap Valley . . . 

Whitmore Wash . . . 

Separation Canyon

Pigeon Wash .....

1 See figure A1.

Measured section

Blue Spring ........

Horsetrail Canyon . . .Kaibab Trail, south

Thunder River Trail . . 

National Canyon . . .

Tuckup Canyon .... Toroweap Valley . . . Whitmore Wash .... 

Parashant Canyon . . . 

Twin Springs Canyon 

Separation Canyon . .

Guano Cave ......

Gravel

Number

8 Jasper, chert, flint, siltstone, limestc

15 Jasper, chert, quartz, rare siltstone,

21a Mostly jasper, some limestone, silt;

Common 

size range 

(in inches)

>ne ........ 0.25 -0

........... .25

limestone . . .125- 

........... .25 - ........... .25 - ........... .25 - ...... .... .125-

........... .25 - l. 75 .5.5 .5 .5 .5 .5 .25 .5

Maximum . , Thl,C un5ss diameter Roundness of bed

(in inches) < ln feet >

1.5 Subrounded ......1 Subangular, subroun 

1 Angular to subanguL 

0.5 

3 Angular chert, rounc 3 Angular to subangul. 

2 ............. do

4 .............. do

1.5 Angular to subrounc 

1 Angular to subangul; 

0.25 

2 Subangular to round

TABLE J 2.— Occurrence, composition, and physical properties of pebbles and cobbles in Wescogame

[Leaders (---) indicate data lacking]

Gravel composition

Siltstone .......................

Siltstone, silty limestone, mudstone - White chert, siltstone, limestone . . . 

White chert, jasper, some limestone

Limestone, siltstone, some chert, 

jasper.

Common 

size range 

(in inches)

0.25 -0.5 

5 -2

.25 - .5 .5 -1

1 -3 

.125- .5.5 -2 

.125- .25 

.25 - .5 

.25 - .5 .5 -1

.25 - .5 

2 -3

Maximum 

diameter 

(in inches)

3 8

1 

38

1

9 0.5 

6 

2 

3

1 

6

Roundness

Rounded ..............Rounded to subrounded . . 

Angular to Subangular ....

Rounded, except chert . . . 

Angular, except limestone

......... do. .........

Angular chert, rounded 

limestone.

............... 10.0

ar ............. 1

1 

Jed limestone . . . 5.51............... 3............... 7led ............ 6ar ............. 1.5

6

led ............ 7.5

basal conglomerate

Type of occurrence

......... do. .........

Scattered gravel on channel 

margins.

Channel fill .............

....... do. ................. do. .........

......... do. .........

....... do. .........

........ do. .......

Distance above 

formation base 

(in feet)

79.5 

60,66 

82 86 

112 

5 85 

95 

109 

92 

150 162 

64

Maximum 

thickness 

(in feet)

4.0 

10 

2 

1 

3

9

1 

18.5 

23 

11 

1 

2 

8 

2

2 

3

THE SUPAlGROUP OFGRAND CANYON

1 See figure A1.
CONGLOMERATES 193

Morrowan strata and the fossils that occur above it in the 

same stratigraphic sequence. The conglomerate is believed 

to be the basal deposit of this sequence, formed after a 

hiatus of unknown, but probably not great, duration.

WESCOGAME BASAL 

CONGLOMERATE

Near the base of the cliff unit of the Wescogame Formation a distinctive conglomerate has been recognized at 

more than half of the basal Wescogame exposures examined in the Grand Canyon. This conglomerate overlies a 

widespread erosion surface and, in places, fills channel 

scours of appreciable width and depth. In a majority of 

localities, especially in western Grand Canyon, however, 

it constitutes a relatively even, persistent bed of 2- to 3-ft 

thickness that initiates a sequence of largely cross-bedded 

detrital deposits believed to be of Virgilian age.

The rock upon which the conglomerate was deposited 

differs considerably from place to place, but, in general, 

gravels rest upon structureless to flat-bedded siltstone and 

mudstone in eastern Grand Canyon and on cross-bedded 

sandstone or limestone in western Grand Canyon. Thicknesses of channels at this horizon were determined to have 

been 15 ft deep (fig. H7) at Thunder River Trail, 80 ft deep 

(figs. H8, H10) at Havasu Canyon, 18.5 ft deep (table J2) at 

S B Canyon, and 35 ft deep (fig. H7) at Tuckup Canyon—measured sections all in the central part of the region 

(fig. Al). Farther east small channels were noted at 

Horsetrail Canyon, Hermit Trail and elsewhere, but in sections of western Grand Canyon few channels were observed (table HI).

The Wescogame basal conglomerate has a general overall color ranging from pale grayish brown, where limestone pebbles are dominant, to grayish red brown where 

dark chert and jasper form the major constituents. The 

matrix in the conglomerate is composed of a gray sandy 

limestone in many places, but it consists of a gray to rustybrown calcareous siltstone or very fine grained sandstone 

at Thunder River Trail, Separation Canyon, and some 

other localities.

The gravel fractions of the conglomerate consist of two 

very different elements (table J2) that doubtless reflect 

distinct sources and are represented in greatly differing 

proportions at various localities. These elements are (1) 

relatively weak limestones and siltstones, and (2) very 

durable, resistant cherts and jaspers. The limestones range 

from dark gray to light gray and from pink to purple; the 

siltstones are mostly red brown or grayish pink. Chert 

ranges from light gray to cream to dark gray or brown and 

the jasper is typically dark reddish brown.

The limestone and siltstone pebbles are mostly well 

rounded, or at least subrounded, and commonly have 

diameters of 0.5-1.0 in. In the Thunder River Trail, Horsetrail Canyon, and Toroweap Valley sections rock sizes of 

8-9 in. were measured among limestone cobbles, but at 

Blue Spring, Hermit Trail, and Separation Canyon 3 in. 

was the largest size noted. In contrast, chert and jasper 

particles probably average between 0.125-0.5 in. in 

diameter and the maximum recorded was 1 in. Many chert 

pebbles are very angular and most are subangular; they 

tend to have irregular shapes and many are tabular.

Lithology of pebbles and cobbles in the Wescogame conglomerate (table J2) differs from east to west across the 

region in a crude distribution pattern. At Blue Spring and 

Horsetrail Canyon on the Little Colorado River and at 

Bunker, Kaibab, south, Thunder River, and Hermit Trails 

in eastern Grand Canyon only well-rounded limestones 

and calcareous siltstones are represented in the gravel deposits, occurring for the most part as scattered pebbles or 

as small concentrations of pebbles in pockets. In central 

Grand Canyon many of the gravel deposits consist mostly 

or entirely of chert or jasper, or both. In western Grand 

Canyon thin beds containing rounded limestone and siltstone pebbles, but commonly including some jasper or 

chert pebbles, seem to be typical.

No obvious relation between channel deposition and 

rock type is apparent. Deep, buried channel deposits at 

National Canyon and Toroweap Valley are almost entirely 

composed of angular chert and jasper, a channel fill at 

Thunder River Trail contains rounded limestone pebbles 

only, and channel scours at S B and Tuckup Canyons are 

filled with silt and fine sand and lack gravel (table J2).

The source of all gravel composing the Wescogame basal 

conglomerate probably was relatively local, and few, if 

any, of the cobbles and pebbles were introduced from 

beyond the northern Arizona region. Most of the lithologic 

types represented apparently are those of underlying Supai 

strata and the lack of any appreciable mixture at most localities suggests local derivation. In many places, all pebbles have the same composition and apparently were 

derived from a single rock unit nearby. The marked 

angularity of chert or jasper fragments in many outcrops is 

evidence of little wear from transport; the well-rounded 

limestone and siltstone pebbles common in some localities 

did not necessarily move long distances as such roundness 

may readily be attributed to the very soft and (or) friable 

nature of the rocks involved, rather than to transport 

distance.

The composition and general character of the gravel (fig. 

J3) suggest that at the time of deposition, strata that 

underlie the Wescogame conglomerate were already lithified. Not only had strata forming channel walls been consolidated into limestones, sandstones, and siltstones, but
194 THE SUPAI GROUP OF GRAND CANYON

FIGURE J2 (above and facing page).—Atokan conglomerate, at base of 

upper slope unit of the Watahomigi Formation. Base of Atokan rocks. 

Mostly of chert and reddish-brown jasper, with angular, closely 

packed clasts. A, B, S B Canyon, 85 ft above base of Watahomigi; C,

o\ x \

,a v \ 3

\^ \ ^:e ^

* --^\^r^V^U>

0

vt*,0**-"

^ ••;,.;

-•"* •* W.

sr*S-. it-*" s

^'j--. w

1 ^^' .-1^'

Thunder River Trail; D, Whitmore Wash; E, Toroweap Valley, west 

side; F, Whitmore Wash, flat-bedded and cross-bedded, angular chert 

fragments; C, Tuckup Canyon, chert conglomerate on purple 

calcareous mudstone.

also jasper had been deposited along bedding planes and 

across strata. Jasper is common locally in the form of pebbles and cobbles. Thus, the erosion surface below the conglomerate probably represents a hiatus of considerable 

magnitude that, as suggested by paleontological evidence 

from the western Grand Canyon region, separated deposition of the Atokan Provincial Series from that of the 

Virgilian Provincial Series.

BASAL CONGLOMERATE OF 

THE ESPLANADE SANDSTONE 

AND PAKOON LIMESTONE

The most widespread and continuous conglomerate 

in the Supai Group of Grand Canyon occurs in the slopeforming unit underlying the massive sandstone cliff of the
CONGLOMERATES

an :' ~" m ~ . *& r- TJJ • -^ ^"s^

195

Esplanade (fig. Hi). In western Grand Canyon this conglomerate occurs in the same stratigraphic position in the 

lower slope unit of the Pakoon Limestone (McNair, 1951). 

The Pakoon intertongues with and replaces the lower part 

of the Esplanade in extreme western Grand Canyon. This 

basal conglomeratic unit constitutes an excellent key bed 

or marker bed, as it has been recognized in nearly every 

stratigraphic section measured and studied during this investigation. Throughout the region it is remarkably 

uniform in general character and marks the position of a 

hiatus in the sedimentary record.

The basal conglomerate in many places partly or entirely 

fills channels from a few inches to many feet in depth. Elsewhere it extends evenly for great distances across a nearly 

flat surface of older rock. In a few places, probably where 

topographic highs existed on the depositional surface, it is 

absent.

The deepest observed channels occupied by the conglomerate (table J3) are at mile 16.5 on the Colorado River 

(maximum depth 50 ft); along the Topocoba Trail (depth 

30 ft), in National Canyon (depth 41 ft), and in Twin 

Springs Canyon (depth 34 ft). The widths of most such 

channels are difficult to determine both because in many 

areas the scours merge into one another and because part 

or all of many channel walls are concealed by talus. Six of 

the largest channels examined range in width from about 

200 to 800 ft. Some relatively shallow depressions on 

broadly exposed surfaces, however, have much greater extent. Thus, a wide variety of forms is represented (fig. J4). 

These channel scours were cut mostly in cross-stratified 

sandstone but, in some places, they incised flat-bedded 

siltstone and, in at least two localities, were cut in silty 

limestone.

The extent to which gravels of the Esplanade-Pakoon 

basal conglomerate cover the erosion surface and the 

nature of their vertical distribution differ greatly from 

place to place. Large buried channels near the north 

Kaibab and Topocoba Trails, 17 and 30 ft deep, respectively, and roughly semicircular in profile, are nearly filled 

with conglomerate. In contrast, the gravels within large 

channels exposed in the walls of Tuckup Canyon, Havasu 

Canyon, Kanab Canyon, and some others are restricted to 

layers at channel bottoms. In still other places, as at mile 

17.5 on the Colorado River and parts of S B Canyon, channels of appreciable size contain no pebbles, but are entirely 

filled with siltstone of a type that elsewhere merely forms a 

matrix for, or is interstratified with, the gravels. At National Canyon, the topmost thin bed within a large channel 

is conglomerate, the gravels of'which resemble those near 

the bottom of the same channel; the intervening beds are 

red sandstones. In the walls of Twin Springs and Hidden 

Canyon, conglomerates occur as lenses bordering the 

channel rims.

The Esplanade-Pakoon basal conglomerate in all of the 

more than 30 localities in the Grand Canyon region where 

it has been examined has a general uniformity in appearance and in composition. Nearly everywhere it forms 

a moderately resistant ledge that is dominantly red brown, 

but locally gray, depending upon the type of pebble that is 

most prominent in a particular place.

Pebbles and cobbles in the conglomerate consist almost 

exclusively of siltstones and limestones, but uncommon 

sandstones and mudstones are included in samples representative of a few localities (fig. J5). These lithologic types 

seem to be limited to the kinds of rock represented in 

various older units of the Supai, but they include many
196 THE SUPAI GROUP OF GRAND CANYON

> OH 9* ?' V.v^

FIGURE J3.—Wescogame Formation, conglomerate at base of cliff 

unit, bottom of Virgilian strata. Pebbles mostly siltstones and limestones, some cherts. A, Channel-fill conglomerate at Thunder River 

Trail; 8, rounded pebbles in Wescogame basal conglomerate at 

Horsetrail Canyon; C, conglomerate at Guano Cave section with 

resistant chert pebbles etched in relief, siltstone and limestone pebbles bevelled; D, angular chert clasts forming conglomerate at Whitmore Wash; E, rounded clasts or red siltstone and gray limestone in 

Wescogame basal conglomerate at Separation Canyon; F, gravel conglomerate at bottom of deep channel scour, at base of Wescogame 

Formation, Havasu Canyon. Scale in inches unless otherwise noted.
CONGLOMERATES 197

-70-

-180 I I I I I I I I I ,T~I

B

F ,

FIGURE J4.—Erosion surface and conglomerate at base of Esplanade 

Sandstone or Pakoon Limestone (McNair, 1951). A, Series of channels 

at Esplanade-Wescogame unconformity, Marble Canyon, mile 16.5; 

B, margin of channel at base of Pakoon, Snap Canyon; C, wall of 

channel carved in sandstone of Wescogame Formation, Esplanade 

fill includes two conglomerate beds, National Canyon; D, basal

EXPLANATION

Sandstone 

Homogeneous

Planar cross-stratified 

Trough cross-stratified

Flat bedded

Limestone 

Homogeneous

Sandy

Sandy cross-stratified 

Siltstone

—~~— Mudstone

Conglomerate

Esplanade conglomerate filling channel at top of Wescogame, 

Kaibab Trail, north; £, surface of erosion truncating two sets of crossstratified sandy limestone, Hidden Canyon, north side; F, Esplanade 

basal conglomerate lenses in a channel cut into upper surface of 

Wescogame, Twin Springs Canyon. Horizontal and vertical distances 

in feet.
TABLE J3.— Character/stars of basal conglomerate of the Esplanade Sandstone and Pakoon Limestone (McNair, 1951) underlying er

(Leaders (--) indicate data lacking. Is, limestone; sits, siltstone]

Measured section 1

Name

(Apache Trail).

(Apache Trail).

. . 1a

. . 2

.. 3

. . 5

. . 7

. . 8

.. 9

. . 10

. . 11

. . 12

.. 13

14

14

. . 15

Channel Underlying

Depth Width strata

(feet)

50 260

15 60+ Siltstone .............

0.3 1.0 Claystone ...........

17 250 Cross-bedded

siltstone.

15 240 Shaly siltstone ........

2.5

12 20 Thin-bedded

sandstone.

47 144 Cross-bedded

sandstone. 

22 825 ........ do. ........

41 85 Limestone and

sandstone.

Position of

conglomerate

.......... do. .......

sandstone lenses.

Fillschannel;

siltstone tongues. 

Continuous bed ......

channel bed above.

forms bed. 

On channel sides

and floor.

Channel floor only ....

top.

top.

Maximurr 

gravel

diameter

18.0

4.0

3.0

4.0

1.0

5.0

3.0

2.0

1.5

3.5

... 18.0

3.0

8.0

i Common 

size

range

(inches)

0.5 -1

0.25 1

0.25 0.5

0.5

0.25

0.5 -1

0.25-0.5

0.25 0.75

0.5 -1

0.25-1

n Tc 1

0.5 -2

0.5

Gravel

Composition

siltstone, 

sandstone.

siltstone. 

.... do. ....

.... do. ....

Siltstone,

sandstone, 

limestone. 

Siltstone,

limestone, 

mudstone.

limestone. 

.... do. ....

.... do. ....

.... do. ....

Limestone,

sandstone, 

siltstone. 

Limestone,

sandstone, 

siltstone. 

Jasper.
CONGLOMERATES 199

Sand

E ~

a; oi £

2 I "

£ d £ -g

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£ o

a; £

2 __ <x* -D

c

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Oi C Oi

"D ro -o -X -^ P P P

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O1 O1 O1 OJ

QJ Oi

O E E c c c O -r o

to QJ O O O O O ..

^i/^i/^i/^^/^i/^*;^^ i± o»±;-ci; E^ E

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o ^ 8 ^ E ^ 

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w C i^

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o ; u

LO o c

^ — '• oc

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1 S i

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lc = c

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ro

d

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1 

.

O 1^1 -— 1^1

_D ~O c ~&

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H Q U

T3

0 

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2

u

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o;

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ro

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estone.

_E

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ro 

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-D

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LA

estone.

_E

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g

U

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Oi ~O 

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estone.

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U
200 THE SUPAI GROUP OF GRAND CANYON

\

r:

FIGURE )5 (above and facing page).—Basal conglomerate of Esplanade Sandstone and 

Pakoon Limestone (McNair, 1951) showing well-rounded surfaces of clasts and wide range 

in size from granule to cobble; composed almost entirely of red siltstones and gray 

limestones. A, Havasu Canyon; 6, Twentynine Mile Canyon (Marble Canyon); C, Kaibab 

Trail, north (polished face); D, Snap Canyon, base of Pakoon Limestone; E, Seligman 

(Aubrey Cliffs); F, Bass Trail; C, Blue Mountain Canyon. Scale in inches. All are Esplanade 

except D, which is Pakoon.

varieties of each as judged by color, texture, and other 

attributes. Apparently they were derived from numerous 

different local sources throughout the region. Limestones, 

for example, include pale-gray, medium-gray, olive-gray, 

brownish-gray, pale-red, purple, and dark-gray varieties 

and several distinct textures. Two to four different limestone types are represented in most outcrops. Likewise, 

siltstones can readily be classified into numerous distinct 

types; at least six color varieties, mainly reddish browns, 

are recognized.

Unlike older conglomerate units in the Supai Group, the 

Esplanade-Pakoon basal conglomerate includes extremely 

few gravels derived from hard, durable rocks such as

quartzite or chert. A few jasper pebbles from National 

Canyon and from Separation Canyon and some palebrown cherts from Blue Mountain Canyon are the only exceptions recorded from the entire region. Of the other conglomerate units in the Supai, only the Wescogame basal 

conglomerate contains gravels with a composition that 

even slightly resembles that of the Esplanade-Pakoon with 

respect to scarcity of durable rock types.

The range in size represented by gravels of the Esplanade-Pakoon basal conglomerate is considerable (table J3). 

A boulder with an 18-in. diameter at the Topocoba Trail 

measured section and one with a 10-in. diameter at Iceberg 

Canyon are the largest observed during this study, but
CONGLOMERATES 201

cobbles ranging from 3 to 8 in. in diameter were noted at 

18 measured sections. Gravels with diameters between 

0.25 and 1 in. occur at all measured sections and constitute 

a major part of the conglomerate throughout the region. 

Most of the gravels of all sizes are rounded or subrounded; 

only a few exceptions, determined to be subangular, have 

been noted.

A majority of all gravels in the Esplanade conglomerate 

are either spherical or elliptical, because they have been 

derived largely from uniform-grained siltstone and limestone. Locally, where shaly or platy source rocks contributed some of the pebbles, tabular forms are included. 

Many of the very large gravels are irregular in shape, apparently not having been transported far enough to 

develop good sphericity.

The attribute of orientation is weakly developed among 

these gravels, partly because most deposits contain a high 

percentage of nearly spherical forms and such forms cannot 

show alinement in a preferred direction. Among tabular and 

ellipsoidal pebbles, however, an orientation roughly parallel 

to the bedding plane is locally developed. No imbricate 

structures have been observed in the conglomerate.

The matrix of the Esplanade basal conglomerate is predominantly very fine sand or silt. However, in the far 

western part of the region bordering the Cordilleran geosyncline at Iceberg Canyon and along the Grand Wash 

fault (at Snap Canyon, Pigeon Wash, and Hidden 

Canyon), a matrix of granular limestone is characteristic of 

the conglomerate that occurs at the base of the Pakoon 

Limestone at these localities.

A second or upper bed of conglomerate, similar in 

most respects to the Esplanade-Pakoon basal conglomerate, occurs within the slope unit below the main cliff of 

the Esplanade Sandstone in the central Grand Canyon 

area. This conglomerate is at Bass Trail, Havasu, National, and S B Canyons, Toroweap Valley, and Whitmore 

Wash and may be represented at Blue Mountain Canyon. 

At these localities the bed is somewhat thinner and the 

maximum pebble size less than in the Esplanade basal conglomerate below. The beds of fine detrital sediments between these conglomerates at the localities examined differ 

considerably in thickness, but mostly they range between 

20 and 50 ft.

The history and depositional environment of the Esplanade-Pakoon basal conglomerate probably can be interpreted with reasonable accuracy from a consideration of 

the types of gravel included and from the character of 

the erosion surface that these gravels cover. Because the 

gravels probably were derived entirely from various lithified sediments representing earlier stages in the history of 

the Supai and contain no presently known foreign or exotic rock types, a source within the northern Arizona 

region seems likely. Furthermore, the generally good 

rounding of most pebbles and the large variation in rock 

types suggest that a moderate amount of transport was involved and that a considerable number of different lithologic units contributed to the deposits.

The surface on which gravels of the Esplanade-Pakoon 

basal conglomerate accumulated seems to have been fairly 

uniform across a wide area and to have resulted from erosion of a slightly elevated plain. It was everywhere
202 THE SUPAI GROUP OF GRAND CANYON

dissected by streams to form a network of narrow channels, some having depths of 30 or 40 ft. These channels 

were subsequently filled or partly filled with pebbles or 

cobbles, and a thin sheet-like deposit of gravel was spread 

over most of the interfluve surfaces. Probably a regional 

change in base level initiated this change from erosion to 

deposition, but the exact cause is not apparent.

The time represented by the Esplanade-Pakoon basal 

conglomerate and the underlying surface of erosion involves the time required to lithify the strata of silt, sand, 

and calcium carbonate that underlie the erosion surface, 

the time involved in slight regional uplift (or possibly 

lowering of sea level), and the time required to accumulate 

the gravel. None of these processes necessarily represents 

very much time in a geologic sense, but rocks above the 

hiatus are dated as Permian (Wolfcampian) age on the 

basis of fossils at a number of localities, whereas those 

below are considered of Late Pennsylvanian or Virgilian 

age, but with weaker faunal support as discussed in 

chapter E.

EROSIONAL SURFACE AT 

BASE OF THE HERMIT SHALE

An erosional unconformity at the top of the Esplanade 

Sandstone was discovered in 1916 by Noble (1922, p. 63), 

and briefly described two years later by Schuchert (1918, 

p. 35t>). After further examination in which this erosion 

surface was found to be "continuously traceable for at least 

15 miles in the Kaibab division," Noble (1922, p. 64) proposed that it be recognized as the lower boundary of his 

newly recognized Hermit Shale. Its general character as 

developed near the Hermit Trail is illustrated in his plates 

XXIIIB and XXIVA and his figure 4a. Also its profile as 

observed below Havasupai Point is shown by diagrammatic sketch in his figure 4fo.

TABLE \4.—Characteristics of the surface

Subsequent to Noble's investigation in the eastern part 

of the Grand Canyon, studies of the Hermit-Supai contact 

have been made in many other parts of the region. In a 

number of areas no evidence of a physical break has been 

detected, and at these places a boundary between formations can be established only by placing it arbitrarily where 

a lithologic change occurs. Thus, the significance of the 

surface as a record of regional erosion seemed questionable. However, because evidence of an erosion surface at 

this horizon has now been found at 10 or more places 

(table H2) beyond the area of Noble's investigation, the 

concept of a widespread erosion surface at this horizon 

seems valid.

The surface of relief represented at the contact of the 

Supai Group and Hermit Shale is of two principal forms. 

In one the surface is flat and regular for considerable 

distances with relatively few widely spaced channels incised into it. These channels (table J4) commonly are 30-45 

ft deep and 100 to several hundred feet wide; they are filled 

with beds of shaly siltstone of the Hermit that commonly 

dip from the channel margins toward the centers. The 

second type of surface is the result of more complete 

dissection where major parts of the original surface have 

been removed so that only isolated residual hills or remnant mesas of Esplanade Sandstone stand above an erosion 

plain. In places, these residuals are only 3-8 ft high and a 

few hundred feet wide, but at National Canyon a mesa 

more than 100 ft high and 1,000 ft wide is preserved 

(fig. HIS/).

At only three places—Bunker Trail, Thunder River 

Trail, and National Canyon—were conglomerates noted at 

the base of the Hermit. These form small lenses or pockets 

of what appear to be locally derived pebbles and granules 

of siltstone or limestone. Elsewhere, thin units of reddishbrown, shaly siltstone that fill the channels or form the 

base of the Hermit locally contain abundant fossil plant 

impressions (Walchia, Sphenophyllum, seed ferns, and

of relief at the base of the Hermit Shale

[Leaders (—) indicate data lacking]

Locality

Residual 

relief 

(in feet)

Hill Channel Associated

width Depth Width structures 

(in feet) (in feet)

Associated 

fossils

Badger Canyon .....

Bunker Trail .......

Kaibab Trail, south .. 

Hermit Trail .......

Topocoba Trail 

Havasu Canyon .....

Thunder River Trail .. 

Kanab Canyon .....

National Canyon ....

Tuckup Canyon ... 

Whitmore Wash . .. 

Twin Springs Canyon

114

3

400

1,000

70

46 

40

Large 

30 

38

15

30

300

Conglomerate lens

100 Rain pits, mud cracks, salt molds 

75 do.

Conglomerate bed 

Conglomerate lens

100+ 

200

Plant impressions, amphibian tracks. 

Plant impressions, tracks, burrows.

Plant impressions, worm borings.
CONGLOMERATES 203

others), shrinkage cracks, rain pits, worm borings, amphibian tracks, and patterns assigned to the algal form 

known as Rivularites. These fossils and structures are well 

represented near the south Kaibab and Hermit Trails and 

at Whitmore Wash.

INTRAFORMATIONAL 

CONGLOMERATES 

IN THE HERMIT SHALE

Evidence of local erosion within the sequence of shaly 

siltstones and mudstones forming the Hermit Shale consists of buried channels and of intraformational conglomerates. Such features are recorded from 14 localities, 

and in 2 of these at more than one horizon. No clear 

evidence is available that these features are continuous 

from one locality to another although, in general, they occur at two principal levels above the formation base. Thin 

conglomerate beds and lenses occur from 49 to 100 ft 

above the base at 7 localities (table J5). Erosion channels 

and (or) conglomerates are in the upper part of the formation, from 215 to 698 ft above the base, at 5 localities.

Intraformational conglomerates of the Hermit Shale are 

largely reddish brown and consist mostly of rounded pebbles of limestone and siltstone in a silty matrix. Individual 

pebbles and granules in most exposures are well rounded 

and, in general, range from 0.125 to 0.5 in. with maximums of 2-4 in. All the pebbles seem to have been locally 

derived, although they apparently were rolled about sufficiently to be moderately well rounded.

Buried channels within the formation are relatively 

small with depths ranging from 6 to 15 ft. They are filled 

with shaly siltstone, the bedding planes of which roughly 

conform with the curving surface of the channel. In these 

channel deposits various fossils and minor sedimentary 

structures are characteristically preserved in abundance.

TABLE J5.— Stratigraphic position of buried channels and local conglomerates above base of Hermit Shale

[Leaders (—) indicate not present]

Stratigraphic position (in feet) 

above base of Hermit Shale

Locality

Whitmore Wash ..........

Tower of Babylon .........

Blue Mountain Canyon .....

National Canyon ..........

Havasu Canyon ...........

Topocoba Trail ...........

Bass Trail ................

Kaibab Trail, north .........

Grandview Trail ...........

Bunker Trail ..............

Blue Spring ...............

Horsetrail Canyon .........

Eminence Fault ...........

Twentynine Mile Canyon . . .

Channel

100

215

216

...

...

138

...

241

...

64

52

72

...

301

698

Conglomerate

—

...

...

49

76

...

94

„.

98

73

...

65

311

89

Worm burrows and amphibian tracks were recorded at 

Whitmore Wash, impressions of the coniferous plant 

Walchia at Blue Mountain Canyon, rain pits, plant impressions, and worm tubes at both Topocoba and Bass 

Trails, and the algal form Rivularites at Twentynine Mile 

Canyon.

REFERENCES CITED

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern

Arizona: American Association of Petroleum Geologists Bulletin, v.

35, no. 3, p. 503-541. 

Noble, L. F., 1922, A section of the Paleozoic formations of the Grand

Canyon at the Bass Trail: U.S. Geological Survey Professional Paper

131, p.23-73. 

Schuchert, Charles, 1918, On the carboniferous of the Grand Canyon

of Arizona: American Journal of Science, 4th ser., v. 45, no. 267,

p. 347-361.

THE SUPAI GROUP OF GRAND CANYON

SANDSTONES

Chapter K 

By EDWIN D. McKEE

Contents

Page

Sandstones of the Supai Group .............................................................. 207

General features ... ............ .................................... 207

Methods of study ................................................................ 207

Geometry of sandstone bodies ... ... ................................... 207

Grain-size distribution in Supai Group .......................................... ...... 208

Sand-silt ratio ... ................................................................. 208

Sorting of sand in Supai Group ......................................... ..... 208

Grain roundness in Supai Group ....... ................................................ 209

Skewness in sand of Supai Group ....................................... ... 209

Cross-stratification in the Supai Group ................................................... 209

Characteristic features ..................... ....................... 209

Statistical studies of current directions .............................................. 210

Plotting of data ....................................... ......... ............. 211

Ripple marks in sandstone ............................................................. 211

Sandstone of the Watahomigi Formation .................................... ....... 211

Geometry of Watahomigi sand bodies ........... ..................................... 211

Grain-size distribution in Watahomigi Formation ........................................... 211

Cross-stratification in Watahomigi Formation ............................................. 211

Sandstone of the Manakacha Formation ........................ . . ......... ....... 213

Geometry of Manakacha sand bodies .................................................... 213

Grain-size distribution in Manakacha Formation ........................................... 216

Cross-stratification in Manakacha Formation ................... ................... ... 216

Characteristic features .......... ................... ....... 216

Current directions ....................................................... ..... 220

Ripple marks in sandstone .... . . .............................. 220

Contorted bedding ................................................................... 221

Sandstone of the Wescogame Formation ...................................................... 221

Geometry of Wescogame sand body ...................................... .. .... 221

Grain-size distribution in Wescogame Formation .......................................... 222

Cross-stratification of Wescogame Formation ....................................... ... 222

Characteristic features ............................................................. 222

Current directions ...................................... .. ................... 224

Ripple marks in sandstone ............................................................. 224

205
206 THE SUPAI GROUP OF GRAND CANYON

	Page

Sandstone of the Esplanade Sandstone ....................................................... 229

Geometry of Esplanade sand body ....... .. ...................................... 229

Grain-size distribution in the Esplanade Sandstone ......................................... 229

Maximum grain size ......... .. .. ............................... 229

Medium and finer size grades ....................................................... 229

Cross-stratification of Esplanade Sandstone ................................................ 229

Characteristic features ............................................................. 229

Current directions ................................................................ 235

Ripple marks in sandstone ............................................................. 236

Contorted structures ........................ ................... ................... 237

Structureless sandstone ..................................... ........................ 241

Small-scale structures in associated siltstone lenses ......................................... 241

References cited ........................................................................ 242

Illustrations

Page

FIGURE K1. Dominant size grade, Watahomigi Formation ................................. 212

K2. Sketch showing small-scale structures of the Watahomigi Formation ............... 212

K3-K8. Manakacha Formation:

K3. Chart showing maximum grain size ............................... 213

K4. Chart showing dominant size grade ................................ 214

K5. Sketches of styles of cross-stratification in cliff unit .................... 215

K6. Photographs showing cross-strata .................... .... .... 217

K7. Polar coordinate diagrams showing cross-strata dip directions, average

dip direction, and degree of dip .................... ........... 218

K8. Map showing dip-direction vectors ..... ..... ................... 221

K9-K17. Wescogame Formation:

K9. Chart showing maximum grain size ............................... 222

K10. Chart showing dominant size grade ................................ 223

K11. Sketches showing planar cross-strata and trough-like cross-strata ...... 224

K12. Sketches showing tabular-, wedge-planar and trough sets ............... 225

K13. Sketches showing tabular- and wedge-planar cross-strata ............... 226

K14. Photographs showing cross-strata ................ ............... 228

K15-K16. Polar coordinate diagrams showing cross-strata dip directions, average

dip direction, and degree of dip .................. ....... .... 230

K17. Map showing dip-direction vectors ... ............ ......... . 234

K18-K21. Esplanade Sandstone:

K18. Chart showing maximum grain size ..................... ....... 235

K19. Chart showing dominant size grade .... ... 236

K20. Photographs showing size-scale of cross-strata . ....... .......... 237

K21. Polar coordinate diagrams showing cross-strata dip directions, average

dip direction, and degree of dip ..................... ......... 238

K22. Polar coordinate diagrams showing cross.strata dip directions, average dip direction, and degree of dip of the Esplanade Sandstone and the Pakoon Limestone .... 240

K23. Map showing dip-direction vectors, Esplanade Sandstone .......... 241

K24. Map showing dip-direction vectors, Pakoon Limestone ......................... 242

K25. Sketches showing small-scale cross-strata and contorted bedding in the Esplanade

Sandstone . ... .................................................. 243

Tables

Page

TABLE Kl. Sorting (Payne scale) of sandstones in the Supai Group ................ .............. 209

K2. Phi quartile skewness of sandstones in the Supai Group ............... .............. 209

K3. Percent of size grades in adjacent foreset and bottomset beds of a cross-stratified sandstone unit of the Wescogame Formation .......... ......... ................ 210

K4. Relative abundance of principal types and size classes of cross-strata in the upper three

formations of Supai Group ... ...................... . . . . .... . . 214

K5. Number and types of cross-strata sets included and thickness of cosets in sandstones and

arenaceous limestones in the upper three formations of the Supai Group . 216 

K6. Degree of dip in cross-stratification in upper three formations of Supai Group .............. 220

K7. Proportions of sandstone and siltstone in Supai Group ................................ 229
SANDSTONES 207

SANDSTONES OF THE 

SUPAI GROUP 

General features

Sandstone constitutes the major rock type of the upper 

three formations (Manakacha, Wescogame, Esplanade) of 

the Supai Group (figs. C10-C13) and it forms small local 

deposits scattered among the siltstone and limestone beds 

of the lowermost formation (Watahomigi). Most of these 

sandstone units are composed of thick, massive beds, extensively cross-stratified, but in some places they appear to 

be structureless. Locally the sandstone is flat bedded and 

forms relatively thin sets.

In order to understand the nature of various bodies of 

sandstone within the Supai Group, to compare one with 

another, and to interpret the genesis of each, their various 

properties were studied and analyzed from as many approaches as possible. Results of these studies, presented in 

this chapter as they apply to each of the four formations of 

the Supai Group, include the following attributes: geometry of sandstone bodies, grain-size distribution, sorting 

of sand, grain roundness, skewness, cross-stratification, 

ripple marks and other minor structures, and contorted 

bedding.

Interpretation of the sandstone bodies in each formation 

of the Supai Group is largely deferred until Chapter L, 

which is entitled "Environment of deposition of sandstone 

bodies." Although a majority of the basic data used for 

interpretation is described and discussed in this chapter 

(K), much supporting evidence is from other chapters, 

especially those concerning associated rocks of other types 

and their faunas or floras. Additional information on interpreting depositional environments is treated in chapter I 

under "Transgression and regression."

grain forming the Wentworth size grade that is largest by 

weight in a sample. This category is referred to as the 

"dominant size grade."

Methods of study

Sandstones of the Supai Group are composed almost 

entirely of quartz sand grains with a calcareous cement. 

The proportions of each differ greatly from place to place, 

especially from a regional standpoint. Weakly cemented 

sandstones grade into very calcareous sandstones and 

these may grade into arenaceous limestones. To determine 

the status of a particular sandstone sample or bed, standard 

methods of treating with acid to eliminate calcium carbonate, of screening to determine the amount of each size 

grade, and of weighing to ascertain the percent of each 

grain size, were used. The Wentworth scale, summarized 

below, is used throughout the chapter to express grain-size 

measurements. These measurements are indicated either 

by stating the largest size represented in a sample which is 

termed "maximum grain size," or by indicating the size of

Wentworth scale (Wentworth, 1922)

Very coarse sand 

Coarse sand ....

Medium sand . . . 

Fine sand .......

Very fine sand .. 

Silt ............

Clay ...........

1-2 mm

1/2-1 mm

1/4-1/2 mm

1/8-1/4 mm

1/16-1/8 mm

1/256-1/16 mm

< 1/256 mm

A large proportion of the fine-grained calcareous sandstones and arenaceous limestones in the upper three formations of the Supai Group is cross-stratified; only in the 

Watahomigi are such cross-strata largely lacking. The 

structures (cross-strata) show an infinite variety of detail in 

sections exposed by erosion, some differences being caused 

by slight variations in the laminae, but most of them 

resulting from differences in the angle of dissection. When 

analyzed in three dimensions, however, most of these 

Supai cross-strata resolve themselves into two fundamental types: tabular planar and wedge planar; the trough type 

is uncommon.

In the analysis of cross-strata, which necessarily was 

conducted in the field, five principal attributes were measured and recorded. The resulting averages and trends are 

presented in the form of tables on following pages. The attributes are: (1) the proportions of basic cross-bed types— 

tabular planar, wedge planar, trough type, and small-scale 

migrating ripple forms; (2) the thickness and number of 

sets (and cosets) included in a sand body (McKee and 

Weir, 1953); (3) the length of foresets in a single set of 

cross-beds—referred to as large-scale (>20 ft), mediumscale (1-20 ft), or small-scale (< 1 ft); (4) angle of dip of 

foresets—referred to as high-angle (>20°), or low-angle 

(<20°); (5) directional vectors of foresets—includes the 

mean or average dip direction and the amount of spread 

represented by all dip readings.

Geometry of 

sandstone bodies

Thirty-two measured sections constitute the principal 

source of information from which trends have been projected and extrapolated to reconstruct the geometry of 

sandstone bodies within the Supai Group. These 32 sections in the Grand Canyon region are in two east-west 

series and several relatively short north-south sequences, 

shown in figures P6, P8, P10, and P12.

Except in the Watahomigi, where the relatively few 

sandstone bodies are thin and lensing, most sandstones of 

the Supai Group are tabular bodies that are continuous
208 THE SUPAI GROUP OF GRAND CANYON

throughout much of the Grand Canyon embayment. The 

larger ones extend more than 100 mi east-west and at least 

40 mi north-south. None of them exceed a few hundred 

feet in thickness and therefore they have extremely high 

ratios of lateral extent to thickness. Although most of the 

major bodies are relatively uniform in thickness for 

distances of some tens of miles, they change character 

within short distances where tongues of other lithologic 

facies project into them or, as in the case of carbonate 

rocks, grade laterally into them.

The geometry of the principal sandstone bodies is described in this chapter for each of the formations in the 

Supai Group.

Grain-size distribution 

in Supai Group

The size distribution of quartz sand in sandstones of the 

Supai Group is effectively illustrated both by (1) the maximum grain sizes represented at various localities, and by 

(2) the dominant size grades in samples from these localities. Maximum sizes were ascertained on the basis of approximately 300 mechanical analyses, made with Tyler 

Standard1 screens, of samples judged to be representative 

of the sand units in each locality. Trends in grain-size 

distribution were determined for the principal sandstone 

bodies in each formation and are described under appropriate headings in this chapter.

In addition to the several hundred sand samples for 

which size distribution was determined by screening and 

weighing, about 500 additional samples were checked for 

grain size by a visual-comparison method. This technique 

involved using a binocular microscope for comparing sand 

samples with measured grains mounted on slides. Although 

not as accurate as the sieving technique in indicating the 

proportions of grain size within an individual sample, this 

relatively rapid method served to give a reasonably good 

measure of the distribution of grain size within the various 

sandstone bodies.

Results of the measurements of grain size for the four 

formations of the Supai Group show that by far the most 

common size represented in each is very fine. Maximum 

size ranges up to very coarse grain in a relatively few 

localities, and to coarse grain in many places. The dominant (largest amount of sand) size grade in strata of the upper three formations ranges up to medium sand, although 

this is very uncommon.

A comparison of coarse-sediment distribution in the 

Esplanade Sandstone with that in older units of the Supai 

Group shows a lateral shift in geographic position. 

Whereas in the Manakacha and Wescogame units the

coarsest material is in the eastern and western parts of the 

area and finer sediment is characteristic of the center, in 

the Esplanade Sandstone most of the coarsest sediment is 

in the central, especially the west-central, part of the area.

Sand-silt ratio

A rough calculation of the proportion of sandstone (ss) 

to siltstone (sts.), based on samples of about 1,000 bedding 

sets and representative of the four formations of the Supai 

Group, has been made (table K7). This calculation was 

compiled by determining the dominant grain size, either by 

screening or by the visual-comparison method previously 

described, for all sandstone units as sampled during the 

measuring of stratigraphic sections. It shows a marked upward increase in the proportion of sand to silt as follows:

Esplanade Sandstone .. 

Wescogame Formation . Manakacha Formation . Watahomigi Formation

ss:sts. = 5:1

ss:sts. = 4:1

ss:sts. = 2:1

ss:sts. = 1:3

Sorting of sand 

in Supai Group

Use of trade name in this paper is for descriptive purposes only and does not constitute an 

endorsement of the product by the U.S. Geological Survey.

Despite a considerable range in the size of sand at a few 

localities, a general impression of good sorting is furnished 

by samples from many horizons throughout the region and 

detailed measurements tend to confirm this conclusion 

(table Kl). The Payne scale for sorting (Payne, 1942, 

p. 1707) was applied to more than 130 randomly selected 

samples representative of all units of the four formations in 

the Supai Group. In the Payne system, each sample is 

classed in one of three categories—good, medium (fair), 

and poor—according to the number of Wentworth-scale 

grade sizes that comprise 90 percent of the whole. The 

scale is summarized as follows:

Good sorting—90 percent consists of 1 or 2 grade sizes.

Medium (fair) sorting—90 percent consists of 3 or 4 

grade sizes.

Poor sorting—90 percent consists of 5 or more grade 

sizes.

Sorting in various sandstone-siltstone bodies of the 

Supai Group, using the Payne scale, shows a general 

similarity throughout, with a majority (165) of the samples 

tested showing good sorting and less than half of that 

number (67) showing fair sorting. None showed poor sorting. As illustrated in table Kl, each of the individual formations shows a rather similar pattern of sorting, but 

somewhat different results are found when various units 

within formations are compared. Those units that are 

largely slope-forming and include much silt but little crossstratified sand (low-energy deposits, continental in part,
SANDSTONES 209

TABLE K1.— Sorting (Payne scale) of sandstones in formations of the Supai 

Croup in Grand Canyon region, Arizona

Stratigraphic 

unit

Sorting of sets sampled

Good Medium Poor

Esplanade: 

Upper cliff-slope 

Main cliff ......

Basal slope ....

12

28

15

2

17

1

Total Esplanade 55 20

Wescogame: 

Slope .... 

Cliff .....

7

15

3

10

Total Wescogame 22 13

Manakacha: 

Slope .... 

Cliff .....

12

38

9

11

Total Manakacha 50 20

Watahomigi: 

Upper slope 

Middle cliff . 

Lower slope

17

9

12

Total Watahomigi .............. 38 14

such as those in the Watahomigi) differ from the mainly 

cross-stratified, cliff-forming units that probably were 

formed under higher energy conditions.

Grain round ness 

in Supai Group

The degree of roundness in quartz grains of the Supai is 

believed to be a function of grain size as indicated by the 

distribution pattern described below. The maturity of the 

sand and amount of transportation of the particles seem 

not to be direct causes of the roundness; most of the 

relatively clean quartz sand probably represents second or 

later generations of erosion and deposition.

Examination of more than 900 samples of sandstone 

and siltstone, distributed according to grain size and age 

as indicated on table K7, gives what is considered a reliable measure of roundness for quartz particles in rocks of 

the Supai Group. Observations indicate that nearly all 

sand grains from the very fine grade size (1/8-1/16 mm) 

and coarser, range from rounded to well rounded. Most of 

the quartz grains of silt size (<1/16 mm) are angular to 

subangular.

Skewness in sand 

of Supai Group

An attempt was made to determine whether any marked 

trends in skewness (degree of symmetry of the size 

distribution with respect to the median) are recorded in 

sands of the four formations that comprise the Supai 

Group. For somewhat more than 300 samples, the phi 

quartile skewness (Folk, 1968) was calculated and is summarized in table K2.

TABLE K2.—Phi quartile skewness determined for assorted sandstones in 

Supai Croup

Formation

^Vescoga m e

Watahomigi .........

Percent samples 

skewed (-)

...... 33.6 34

...... 42.0 15

...... 42.3 33

...... 24.5 12

0

79

30

53

46

<+,

6

6

6

3

The results of this study show few differences in skewness among the various formations. In each formation, 

more than half of the specimens are not skewed, and of 

those that show skewness, a much higher percentage is 

negative than positive. The smallest percentage of skewed 

samples is in those sandstones from the Watahomigi. A 

possible reason is that, unlike the other sandstones, they 

were accumulated in an environment of low energy as indicated by a lack of cross-stratification and by other features.

Cross-stratification 

in the Supai Group

Characteristic features

Cross-strata in the Supai Group are largely of the tabular-planar and wedge-planar types, but include some of 

the trough type in the Wescogame Formation and Esplanade Sandstone. Small-scale cross-strata including ripple 

laminae and climbing ripples are uncommon. Most of the 

cross-strata are compound, consisting of sequences with 

superimposed sets of dipping beds that form cosets as 

defined in McKee and Weir (1953, p. 383) that may be as 

thick as 40 ft. These cosets commonly consist of from 2 to 

5 sets, but in places are composed of as many as 10 or 11 

sets in vertical sequence.

A feature of Supai cross-stratification, both in sandstones and in carbonate rocks, that has been recorded and 

studied systematically throughout the group, is its scale. 

On the basis of more than a thousand readings from the 

three upper formations and from 26 localities throughout 

the region, a statistical analysis of this feature has been
210 THE SUPAI GROUP OF GRAND CANYON

made. In classifying the scale of cross-strata, three categories are recognized: small, defined as 1 ft long or less; 

medium, defined as 1 to 20 ft in length; large, defined as 

more than 20 ft long. Large-scale foresets in a number of 

localities are more than 50 ft long and in a few places exceed 100 ft. Small-scale structures, as here defined, are 

formed largely by ripple migration. They are scarce in all 

formations and limited to relatively few localities; most 

commonly they occur in the Watahomigi Formation.

The mean degree of dip on cross-strata foresets has been 

determined for all areas studied and for each formation of 

the Supai containing cross-strata. Classification has been 

into two groups: high-angle strata which dip at 20° or 

more, and low-angle strata in which the dip is less than 20° 

(McKee and Weir, 1953, p. 386). In all three formations, 

the distribution into low-angle and high-angle types is 

nearly equal.

Studies of topset and bottomset laminae in Supai crossstrata indicate that only rarely are these structures represented and that foresets form essentially all cross-strata. 

One of the few good illustrations of topsets to have been 

recorded is in the Wescogame, near the Kaibab Trail, 

south, where horizontal topsets are seen connecting with 

high-angle foresets (fig. K14F). Probably the preservation 

of these topsets resulted from a local rise in water level, 

which prevented the usual beveling of uppermost deposits 

that occurs when water level is stationary or lowering.

Bottomset beds commonly develop because sorting is 

poor and fine-grained sediment moves outward from the 

base of foresets. In the Supai Group, where most of the 

sands have fair to good sorting, bottomset deposits are uncommon, as should be expected. One of the few good examples of bottomsets continuous with foresets is in the 

Wescogame Formation in Bass Canyon. Samples of sand 

from above and below the junction of these units (table 

K3) show in analyses that the percentage of fine grains increases outward from foreset to bottomset deposits.

Statistical studies of current directions

The Supai Group has afforded an excellent opportunity 

for making statistical studies of dips and strikes in crossstratification. The extensive clear exposures in the walls of 

Grand Canyon have permitted accurate measurement of 

bedding surfaces in many places. Systematic work of this 

type was begun in the Supai, with good results, in the late

1930's (McKee, 1940), patterned after the pioneer studies 

elsewhere of Knight (1929), Shotten (1937), and Reiche 

(1938). In all those early investigations, methods of 

graphically representing random observations on crossstratification in order to show the presence or absence of 

dominant dip direction were developed, and techniques 

from each have been used in the present study.

Cross-strata in the Supai used for measurement of dip 

and strike were selected entirely at random. Only one 

recording was made from any single stratum or from any 

one set of strata, except in a few places where trough 

deposits were observed. In trough structures, a reading 

was made of the unit on each side of the axis so that one 

reading would balance the other and show an average 

direction of movement. Where exposures permitted 

measurement down the plunge of a trough, a single 

measurement was made.

In the Supai, because low angles (< 5°) in cross-strata are 

either the result of irregularities on the surface of deposition or of a normal decrease of angle near the base of a 

foreset slope, dip readings of those planes were eliminated 

in determining transport direction of the sediment. On the 

other hand, all slopes greater than 5° were considered to 

have equal importance as indicators of a general direction 

of movement.

Acquiring sufficient readings to insure statistical significance was a prime consideration in determination of an 

average direction of movement. Assurance that 30 

readings from each locality would suffice to give a reliable 

average direction was obtained at the start of the Supai investigation by using consistency curves, such as those used 

by Reiche (1938). Control points were located after 10 

observations and were determined every 5 thereafter. Furthermore, 30 readings proved to be a convenient number 

from a practical standpoint because (1) they could generally all be obtained from a single limited exposure or outcrop, and (2) they normally showed very little overlap of 

points in plotting on a projection sheet.

In addition to obtaining reliable direction vectors for 

specific localities, the importance of obtaining a wide geographic spread of locality vectors required consideration. 

In each of the three formations investigated (figs. K8, K13, 

K23), the general regional direction or trend of cross-strata 

dips for the entire sandstone body was determined on the 

basis of data from 15 to 23 localities distributed over an 

area of approximately 150 mi by 50 mi.

TABLE K3.—Percent of various size grades in the adjacent foreset and bottomset beds of a cross-stratified sandstone unit of the Wescogame Formation, near

Bass Trail

0.500-0.246 mm 0.246-0.124 mm 0.124-0.061 mm

Top of foreset (percent) 

Bottomset (percent) .. .

0.10 0.36 

.10

42.40

17.35

47.60

69.50

9.77

12.97
SANDSTONES 211

Plotting of data

The general direction of dip for the sloping surfaces of 

cross-strata in any area represents the dominant direction 

of movement among the sediments deposited there. On 

this assumption, readings for each locality in the Supai 

have been plotted on polar coordinate sheets (figs. K7, 

K15, K16, K21, K22). Individual directions of dip, and also 

the amount of consistency in direction for any given area, 

thus may be seen at a glance. Furthermore the amount of 

dip, which to some degree illustrates the character of the 

cross-strata, is shown by dots on the polar coordinate 

sheets. These dots are plotted at distances from the center 

proportionate to the degree of dip.

With 30 precise readings of random samples, mean paleotransport (net vector) direction of dip for each locality 

is illustrated (figs. K7, K15, K16, K21, K22). By showing 

these mean directions with arrows on a map of areal distribution, a reasonably accurate picture of the regional trend 

in transport direction is apparent. The degree of accuracy, 

of course, increases with the number of localities represented by measurements, and because of the broad distribution of these localities it is believed that for the Supai 

Group enough samples have been examined to justify some 

generalizations.

Results of these statistical studies of cross-strata and 

their plots are discussed and illustrated under the texts that 

follow on sandstones of the various formations of the 

Supai Group, with the exception of the Watahomigi Formation that has too few cross-strata for significant statistical analysis.

Ripple marks in sandstone

Ripple marks are notably scarce in the various sandstone 

bodies of the Supai Group, despite the fact that current action must have been considerable as indicated by the abundance of cross-stratification in the three upper formations. 

Sequences of ripples were observed in cross-stratified sandstone at only 3 places in the Manakacha, 5 in the Wescogame, and 3 in the Esplanade during investigation of the 32 

measured sections included in this study.

A majority of ripple marks on the surfaces of crossstrata are of the parallel-straight or the parallel-wavy types 

(figs. N3A, N4B). A few have cuspate forms (fig. N3B, 

C)—some linguoid, others lunate in the classification of 

Alien (1963). Ripple crests are oriented at various angles 

with respect to dip of the cross-strata foresets on which 

they repose, but the surfaces containing them mostly have 

low angles—15° or less.

Ripple structures in the Watahomigi are largely in the 

form of ripple laminae and climbing ripples, and most of 

them occur in siltstones and silty sandstones. These structures are discussed in chapter N, together with other minor 

depositional structures.

SANDSTONE OF THE 

WATAHOMIGI FORMATION

Geometry of Watahomigi 

sand bodies

The oldest sandstone beds of the Supai Group are of 

Morrowan age and form a small percentage of the lower 

slope unit of the Watahomigi Formation. They occur mostly as thin flat-lying beds or lenses, interspersed among 

layers of red siltstone and mudstone or between beds of 

carbonate rock. Nowhere do they constitute a large continuous body and only locally are they cross-stratified. 

Cross-bedded sands are too sparse in the Watahomigi to 

give reliable information on current directions. Nearly all 

sandstones in this formation are very fine grained.

The upper slope unit of the Watahomigi is of Atokan age, 

and contains somewhat more sandstone than does the lower 

slope unit of Morrowan age. This sandstone likewise forms 

as interbeds and lenses among fine detrital rock units and 

(or) carbonate beds. The Watahomigi, therefore, is the only 

formation in the Supai Group that does not include an extensive body of sandstone or widespread units of mediumto large-scale cross-stratification. Quartz grains are 

dominantly of silt size throughout the formation and those 

that are larger than silt are nearly all very fine grained sand, 

indicating an environment of low energy.

Grain-size distribution 

in Watahomigi Formation

Unlike overlying units of the Supai Group in the Grand 

Canyon region, the basal Watahomigi Formation contains 

very little quartz sand. The proportions of sand to mud 

(including silt) and of sand to carbonate sediment are so 

small (fig. CIO) that no real attempt to systematically show 

trends in grain-size distribution has been attempted for the 

Watahomigi. Quartz grains of sand size are nearly all of 

very fine grade (1/16-1/8 mm) in this formation (fig. Kl); 

coarser sand grains are very uncommon except as matrix in 

the marine conglomerates.

Cross-stratification in 

Watahomigi Formation

Compared with the abundant medium- to large-scale 

cross-stratification in the three upper formations of the 

Supai Group, cross-strata of all types are very sparse in 

the Watahomigi. However, the examples that have been 

recorded in this formation are so distinctive as to merit 

special consideration. Almost certainly they are the product of low-energy environments very different from those
212

114°

36°-

THE SUPAI GROUP OF GRAND CANYON

113°

EXPLANATION 

Medium-grained

Fine-grained 

Very fine grained

Unit slice, (]/3 quadrant), 

represents one analysis

12 Number of analyses

FIGURE K1.—Dominant size grade of particles in detrital rocks of the Watahomigi Formation in Grand Canyon region, Arizona. Each unit slice (1/3 

quadrant) in a pie diagram represents the dominant grain size for one analysis from the locally indicated. ("Dominant" refers to the principal size 

grade represented by largest amount of sand.) Arrow and miles next to a pie indicate direction and distance to actual sample locality.

EXPLANATION

Sandstone

Cross-stratified

Thin flat-bedded

Very fine grained 

Mudstone

Shells and shell fragments 

of invertebrate fossils

45 —— 45

B

FIGURE K2. — Small-scale structures of the Watahomigi Formation, Grand Canyon region, Arizona. A, low-angle foresets with concentrations and scattered shells of invertebrate fossils, near formation base at Bridge Canyon. B, Channel in sandstone filled with gently 

dipping beds of mudstone, lower slope unit in S B Canyon. Vertical and horizontal distances in feet.
SANDSTONES 213

114° 113° 112°

37C UTAH

o

1®

(3)

EXPLANATION 

Maximum grain size

Coarse 

Medium 

Fine 

Very fine

One unit represents one 

analysis

Number of samples

ARIZONA

(9)

36°

FIGURE K3.—Maximum grain size of particles in detrital rocks of the Manakacha Formation, Grand Canyon region, Arizona. Each unit 

in a vertical bar graph represents the maximum grain size of one sandstone sample (arranged with coarse to fine, from top to 

bottom). Arrow and miles next to bar indicate direction and distance to actual sample locality.

represented in the higher formations, and, therefore, are 

important indicators of the depositional conditions.

Cross-strata of the Watahomigi characteristically are 

small scale. Mostly they are the result of ripple-migrating 

sand (climbing ripple structures and ripple laminae), but 

other types occur. At the east end of Hindu Canyon 

(measured sec. 35), a 2-ft thick bed containing tabularplanar cross-strata occurs at 5 ft above the basal conglomerate. The foresets, which dip at 10°-20°, contain 

concentrations of brachiopods, pelecypods, and gastropods, including many fossil fragments (fig. K2A). In addition, the sand contains scattered subangular fragments of 

chert and jasper. Both the fossils and the pebbles are 

oriented parallel to the dip of the foreset planes.

Ripple laminae (fig. NL4) are recorded from the lower 

slope unit (Morrowan age) at Havasu Canyon and climbing ripple structures (fig. NIB, C) are from the same unit at 

National Canyon. In both localities, they are stratigraphically close to beds bearing marine fossils.

In the upper slope unit (Atokan age) of the Watahomigi, 

additional examples of small-scale cross-strata occur

among the thin-bedded siltstones and limestones below the 

major cliff of the Manakacha. In S B Canyon, a 5-ft channel in massive sandstone is filled with red siltstone foresets 

that dip at 6°-15°. A similar example, in which friable vermilion sandstone fills a channel in jasper-bearing limestone, occurs near the Hualapai Trail in Havasu Canyon.

SANDSTONE OF THE 

MANAKACHA FORMATION

Geometry of Manakacha 

sand bodies

The oldest extensive sandstone body developed in the 

Grand Canyon region during Pennsylvanian time is in the 

Manakacha Formation (fig. P8). Sandstone is largely 

restricted to the upper half of the formation and is thickest 

(120-160 ft) in the east-central and south-central parts of 

the region. The main body of this sandstone is tabular and
214 THE SUPAI GROUP OF GRAND CANYON

113° 112°

EXPLANATION 

Medium-grained

Fine-grained 

Very fine grained

Unit slice, (/3 quadrant), 

represents one analysis

12 Number of analyses

36°

FIGURE K4.—Dominant size grade of particles in detrital rocks of the Manakacha Formation, Grand Canyon region, Arizona. Each unit 

slice (1/3 quadrant) in a pie diagram represents the dominant grain size for one analysis from the locality indicated. ("Dominant" 

refers to the principal size grade represented by largest amount of sand.) Arrow and miles next to a pie indicate direction and 

distance to actual sample locality.

TABLE K4.—Relative abundance of principal types and size classes of cross-strata of upper three formations of the Supai Group, Grand Canyon region,

Arizona (based on 30 cross-strata sets at each locality, selected at random)

[Ta, tabular; W, wedge; Tr, trough; S, small (< 1 ft); M, medium (1-20 ft); L, large (>20ft). Leaders (-») indicate not measured. Numbers in parentheses spanning columns represent a combination of types

or scales]

Esplanade Sandstone

Type

Locality Ta w Tr

Bunker Trail ........ 22 5 3

Hermit Trail ........ 2 28 0

Thunder River Trail ... 12 18 0

Tuckup Canyon ..... 24 6 0

Prospect Valley ...... (30) 0 

Toroweap Valley .... 

Parashant Canyon ....

Pigeon Wash ........ 15 15 0 

Hidden Canyon ..... (26) 4

Scale

S M L

1 20 9

0 29 1 

0 21 9

0 23 7 

0 17 13

0 (30) 

2 12 16

Wescogame Formation

Type

Ta W Tr

17 12 1 

(30) 0

7 23 0 

21 9 0 

27 3 0 

15 0 15 

12 16 2

(30) 0 

9 21 0 

(30) 0 

(26) 4

(29) 1 

22 8 0

Scale

S M L

2 22 6 

0 (30)

0 21 9 

0 16 14 

0 11 19 

16 

0 25 5

7 16 7 

0 23 7 

0 (30) 

0 (30)

3 21 6

Manakacha Formation

Type

Ta W Tr

26 4 0 

10 20 0

18 12 0 

24 6 0

—

Scale

S M L

0 19 11 

0 20 10

0 30 0 

0 9 21

290
SANDSTONES 215

-120-

••...•• .-••<£-

• • ' i'i°'s. •••"!"• •

-12-

B

EXPLANATION

Sandstone

^^."s .

-80-

FIGURE K5.—Styles of cross-stratification in cliff unit of Manakacha Formation in Grand Canyon, Ariz. A, Large-scale planar cross-strata 

and horizontal strata sets in S B Canyon. Foresets 50 ft long. B, Coset of jasper-bearing tabular-planar cross-strata and horizontal 

strata at S B Canyon. C, Tabular-planar set of cross-strata with geniculated basal sections, Bass Trail. Cross-beds 63 ft long. Vertical 

and horizontal distance in feet. Degree and direction of dip shown for cross-strata sets.

intertongues eastward into red mudstone and siltstone, 

although one relatively thin sandstone tongue continues 

northeastward toward the San Juan Basin. Westward, the 

main sandstone body grades into various carbonate rock 

facies, and southwestward, partly into carbonate rock and 

partly into red mudstone. Most of the sandstone is crossstratified on a medium to large scale; similar cross-stratification occurs to the west in carbonate rock that contains 

much quartz sand. In brief, the boundary between sandstone and carbonate rock results from a gradual westward 

increase in the percentage of calcium carbonate or

magnesium carbonate, so is extremely tenuous.

Introduction of quartz sand into the area of Manakacha 

deposition must have been either from the north or the 

south into the east-central Grand Canyon area where the 

greatest thickness of sandstone accumulated. These directions of transport are indicated by relations of the sand 

body to other facies (mudstone, carbonate rock) on the 

east and west. Evidence from grain-size distribution patterns and cross-strata dip-direction vectors strongly supports transport from the north, as indicated by geometry 

of the sand body.
216 THE SUPAI GROUP OF GRAND CANYON

TABLE K5.—Number and types of cross-strata sets included and thickness 

of cosets in sandstones and arenaceous limestones of the upper three 

formations oftheSupai Croup in Grand Canyon (random samples)

Locality

Kaibab Trail, south .

Do. ..........

Hermit Trail .......

Do. ..........

Do. ..........

Topocoba Trail ....

S B Canyon .......

Prospect Valley ....

Toroweap Valley . . .

Do. ..........

Do. ..........

Do. ..........

Do. ..........

Do. ..........

Do. ..........

Do. ..........

Do. ..........

Whitmore Wash . . .

Andrus Canyon ....

Bunker Trail ......

Do. ..........

Kaibab Trail, south .

Do. ..........

Do. ..........

Bright Angel Trail . .

Topocoba Trail

Do. ..........

Do. ..........

Havasu Canyon

Kanab Canyon

Tuckup Canyon ....

Toroweap Valley . . . Do. ...........

Andrus Canyon ....

Snap Canyon ......

Do. ..........

Pigeon Wash ......

Hidden Canyon

Bunker Trail .......

Bass Trail ..........

Havasu Canyon ....

S B Canyon ........

Do. ..........

Toroweap Valley . . .

Do. ..........

Whitmore Wash . . .

Do. ..........

Do. ..........

Snap Canyon ......

Do. ...........

Cosets Sets

Thickness Types

(in feet)

Esplanade Sandstone

. . . 14 Mostly tabular, one wedge ........

. . . 15 Wedge, tabular, horizontal .......

. . . 6 Wedges, tabular, two horizontal . . .

. . . 5 Trough, wedge, tabular ...........

. . . 19 Mostly tabular, one wedge .......

. . . 10 Tabular between horizontal ......

. . . 11 Mostly tabular, one wedge .......

. . . 3 All wedges, one mudstone lense . .

. . . 5 Two wedges, between horizontal . .

. . . 2 All wedges ....................

. . . 2 Mostly tabular, one horizontal ....

. . . 9 Mostly tabular, one wedge,

one horizontal.

. . . 33 Mostly tabular, troughs top and base

. . . 4 All tabular ....................

...27 Mostly tabular, horizontal, wedge .

. . . 10 All tabular. ....................

. . . 25 Horizontal, tabular, wedge .......

...10 Three tabular, three wedge .......

. . . 2 All tabular .....................

Wescogame Formation

. . . 10 Mostly wedge, one tabular ........

. . . 8 Mostly wedge, one tabular ........

. . . 28 Tabular, wedge, horizontal ........

. . . 4 All wedge . . .... .........

. . . 6 Tabular and wedge ..............

. . . 10 Symmetrical trough ..............

. . . 10 Asymmetrical trough ............

. . . 12 Symmetrical trough .............

. . . 12 Symmetrical trough ..............

. . . 30 Tabular ........................

. . . 40 Tabular .......................

. . . 8 Asymmetrical trough ............

. . . 10 All tabular . ....................

. . . 15 All tabular. ....................

. . . — Symmetrical trough ..............

. . . 6 Trough ........................

. . . 4 All wedge .....................

. . . 8 Tabular .......................

10 Mostly wedge, two tabular .......

Manakacha Formation

. . 13 Tabular, wedge, horizontal .......

. . 24 Tabular .......................

. . . — All tabular .....................

. . 20 Tabular, wedge ................

. . . 3 Horizontal tabular ..............

. . . 2 All tabular . .....................

. . . 2 Tabular and wedge .............

. . . 8 All tabular .....................

. . . 6 All tabular .....................

. . . 5 Both tabular and wedge ..........

. . . 8 All wedge .....................

. . 25 Wedge, trough .................

Number

(vertical

sequence)

. 5

. . 6

.. 8

, . 3

. . 10

.. 3

. . 4

.. 7

.. 4

.. 6

. . 4

7

. . 11

. . 7

. . 6

.. 4

-. 6

. . 6

.. 5

. 6

. 6

.. 3

.. 5

.. 5

. . 1

• • 2

.. 3

.. 3

.. 1

2

. . 4

.. 4

.. 6

.. 3

. 5

. . 7

.. 3

.- 11

.. 4

. . 1

.. 3

.. 2

. . 2

.- 3

. . 10

.. 7

. . 5

. . 2

. . 3

.. 5

Grain-size distribution 

in Manakacha Formation

Both maximum grain size and dominant size grade measurements for the Manakacha Formation indicate two areas 

of coarse-sediment concentration. The maximum grain size 

is very coarse sand (1-2 mm) (fig. K3) at Hidden Canyon 

in western Grand Canyon and at both Bass and Hermit 

Trails in eastern Grand Canyon. At several other localities 

in these two widely separated areas the maximum grain 

size is coarse sand (1/2-1 mm). This grain size occurs at 

three sections in western Grand Canyon and at five sections in the east.

The dominant or largest size grade in most sandstones of 

the Manakacha Formation (fig. K4) is very fine grained 

(1/16-1/8 mm); however, at Hidden Canyon in the west, 

fine sand locally forms the dominant grade, and at three 

localities in eastern Grand Canyon it locally constitutes the 

largest or dominant size grade. Thus, although sand of the 

Manakacha Formation is largely very fine grained 

throughout the region, local concentrations of coarser 

sand appear both in the extreme western and in the eastern 

Grand Canyon areas.

Cross-stratification in 

Manakacha Formation

Characteristic features

Cross-stratification of medium to large scale (table K4) is 

a characteristic feature of many rock bodies in the Manakacha Formation—both the sandstone and the carbonate 

facies. In some places (fig. K5), sets composed of exceptionally long foresets are prominent. For example, at Fishtail Canyon near Thunder River Trail and in S B Canyon 

dipping cross-beds ranging between 50 and 60 ft long 

occur, at Havasu Canyon one set about 90 ft long was recorded, and at S B and Kanab Canyons sets more than 100 

ft long were measured.

Nearly all of the cross-strata in the Manakacha are either 

wedge planar, forming cosets of compound cross-strata, or 

tabular planar with layers of dipping foresets repeated 

numerous times in vertical sequence (table K5). The trough 

type has not been recorded. Horizontal strata are locally 

common.

Individual sand bodies, most of which constitute cosets 

(fig. K6) may consist entirely of wedge-planar structures, 

entirely of tabular-planar types, or of both (table K5; fig. 

LI). Some also include sets of horizontal laminae and, 

rarely, of trough types. The number of sets within a coset 

ranges from 1 to 10, and the entire coset (sand body) may 

be 20-25 ft thick, but more commonly is between 4 and 8 ft 

thick.
SANDSTONES 217

*3&'*&S~~r-.1&* V rr?-*r*5t-»ii. ;•*•<....»..-•*•- -Jv

FIGURE K6.—Cross-stratification in cliff unit of the Manakacha Formation, Grand Canyon region, Arizona. A, Large-scale tabular-planar 

cross-strata in S B Canyon; B, small-scale cross-strata on Kaibab Trail, 

south; C, wedge-planar cross-strata in calcareous sandstone, Whitmore Wash; D, jasper bands in tabular-planar cross-beds, Toroweap 

Point; E, tabular-planar cross-strata, Whitmore Wash; F, crosslaminated arenaceous limestone, wedge-planar type, 5 mi south of 

Hidden Canyon.
218 THE SUPAI GROUP OF GRAND CANYON 

N

60

E W

60

Av. 151

E W

60 60

Av. 173 Av. 201

30

60 60

E W

60 60

E W

60

60 60

Av. 189 Av. 204

30

60 60

E W

30

Av. 176

30

E W

60

Av. 209

30

Av. 173
SANDSTONES 219

30 30

Av. 138

30 30

60

Av. 196

FIGURE K7.—Cross-strata dip direction, average dip direction (Av.), and 

degree of dip, plotted on polar coordinate sheets for the Manakacha 

Formation, Grand Canyon region, Arizona. A, Bunker Trail; 8, Kaibab 

Trail, south; C, Hermit Trail; D, Kaibab Trail, north; E, Fishtail Canyon 

near Thunder River Trail; F, Hermit Trail, C, Havasu Canyon; H, 

Toroweap Valley; /, Whitmore Wash; /, Grand Wash Cliffs, 6 mi south 

of Hidden Canyon; and K, Hidden Canyon.
220 THE SUPAI GROUP OF GRAND CANYON

TABLE K6.—Angle of dip in cross-stratification in upper three formations of the Supai Croup, Grand Canyon region, Arizona (based on 30 random samples

of cross-bed sets at each locality)

[Blank spaces indicate not measured]

U

Angle of dip

High angle; 

20 degrees

Low angle; 

< 20 degrees . . .

^ ro

j* cu U

(U C _

S 'E 're

HI

& H X

Trail Bunker Grandview T

- ^ - - a .1

ro DO W 2 1 — iV

5 _LJ < 5 -LJ • ~ — ^ i_ i i— 1~Q 

(^ (— f^ C ' 3 ^

^ oo ^ £ ifi .E ^

ro '^ ro V ro _c -C ^ 02 ^ X m LO H

Topocoba Tr >• c. S >- ^c.

lyi o ;3 

rO ro -^

ro C U

T. -2. H

Vail Prospect Po Toroweap Whitmore W

<3 §» § ^ c u *- TM £• > 1 1 c c U § 5 U c .0

-S o u c 5 | ^ 

1 3 ? .1 1 f gQ- U LO D- -L LO LO

Esplanade Sandstone

.. 16 12

..14 18

22 

8

12 12 17 18 16 13 

18 18 13 12 14 17

Wescogame

High angle; 

20 degrees

Low angle; 

< 20 degrees . . .

.. 9 17 15

..21 13 15 14

23

7

13 15 15 15 17 19 

17 15 15 15 13 11

21 

9

Manakacha

High angle; 

20 degrees

Low angle; 

< 20 degrees . . .

15 

15

17 

13

14 20 15 12 

16 10 15 18

16 11 23 

14 19 17

Formation

12 18 

18 12

Formation

19 

11

19 20 

11 10

18 7 

12 23

19 18 19 21 

11 12 11 9

17 11 7 10 

13 19 22 20

4 

26

The angle of dip on the foresets of cross-stratified rocks 

in the Manakacha is moderately steep (table K6). At nine 

localities where 30 measurements each were made, five 

showed high-angle dips (20° or more) to be dominant and 

four showed low-angle dips (<20°) to be dominant. Most 

cross-strata in the carbonate rocks of western Grand Canyon showed lower angles than sandstone cross-beds farther east.

Current directions

Statistical studies of current-direction trends were made 

of the sandstones and arenaceous limestones in the Manakacha Formation throughout the region. At each locality 

studied, the maximum dip reading was recorded for crossstrata in each of 30 laminae sets selected at random. The 

directions of dip were averaged (fig. K7), and the results 

were plotted on a base map of the region (fig. K8).

Arrows representing average dip directions for the Manakacha show a general southerly direction throughout the 

Grand Canyon region. The averages range from 42° east of

south to 29° west of south, giving a spread of 71°, or less 

than 1 quadrant. Differences in direction show no consistent trend from east to west across the region, and no 

significant interpretation can be attached to the local 

minor differences in direction.

Most of the cross-strata in western Grand Canyon are 

in arenaceous carbonate rocks; those in the east are in 

sandstones.

Ripple marks in sandstone

Both parallel-type ripple marks and cusp-shaped (linguloid, lunate) ripple marks occur sparingly in sandstones of 

the Manakacha Formation. These structures are developed 

on the dipping surfaces of large-scale and medium-scale 

cross-beds and probably were formed after the larger 

structures had been deposited by advancing megaripples. 

Considering the abundance of cross-stratification in the 

sandstone facies, the relative scarcity of ripple marks is 

notable.
SANDSTONES 221

114° 113° 112°

37C

36°

FIGURE K8.—Dip-direction vectors for cross-strata of the Manakacha Formation, Grand Canyon region, Arizona. Each arrow shows average direction determined from 30 measurements of cross-strata selected at random for the locality shown on map.

Detailed descriptions of these ripple marks are covered 

in chapter N under minor depositional structures.

Contorted bedding

Contorted bedding is not a common feature of the Manakacha Formation, but is well developed on a large scale 

near the base of the unit at several localities. Siltstone 

beds, several feet thick, are downwarped to form narrow 

synclinal structures with nearly vertical axes in an 8-ft zone 

that extends more than 300 ft along the walls of Havasu 

Canyon. Horizontal, undeformed beds are directly above 

and below. Similar structures occur along the south wall of 

a canyon near the Kaibab Trail, north. Contorted structures in both places resemble the warping from differential 

loading where sediment is in a quicksand condition. At 

Whitmore Wash, a zone 3 ft thick of crinkled and brecciated sand enclosed by several sets of tabular-planar 

cross-strata was noted.

SANDSTONE OF THE 

WESCOGAME FORMATION

Geometry of Wescogame 

sand body

The Wescogame Formation of Virgilian age contains 

a single large sandstone body of tabular form that extends 

across the entire region (fig. P10). Thickness of the main 

body of sandstone is generally between 75 and 150 ft with 

the thinnest part in central and west-central Grand Canyon.

Like the Manakacha below, the Wescogame intertongues 

with red mudstones and siltstones to the east and with 

limestones and dolostones to the west, but little evidence is 

available to indicate the north-south extent of this sandstone body. Paleogeographic trends suggest that the 

seaway at this time probably connected with both the San 

Juan Basin to the northeast and the Sonoran geosyncline to 

the southeast (fig. D7). Tongues from the main sand body
222 THE SUPAI GROUP OF GRAND CANYON

114° 113

EXPLANATION 

Maximum grain size 

Very coarse 

Coarse 

Medium 

Fine

Very fine 

One unit represents one

36°-

FIGURE K9.—Maximum grain size of particles in detrital rocks of the Wescogame Formation, Grand Canyon region, Arizona. Each unit in a 

vertical bar graph represents the maximum grain size of one sandstone sample (arranged with coarse to fine, from top to bottom).

extend in these directions as evidence of probable extensions of depositional passageways.

Grain-size distribution 

in Wescogame Formation

A comparison of the size-distribution pattern for sand 

grains of the Wescogame Formation with the pattern for 

grains of the underlying Manakacha shows similar positions for areas with concentrations of relatively coarse 

sand. In both formations, two areas of maximum grainsize distribution (fig. K9) and of dominant size grade (fig. 

KlO) are apparent—one in western and the other in eastern 

Grand Canyon.

Maximum grain sizes in sandstones of the Wescogame 

were determined through mechanical analyses by sieving. 

In most samples examined, the sandstones ranged from 

fine to medium grained, but at 10 localities, 5 in the east 

and 5 in the west, coarse-grained sand (1/2-1 mm) also 

was represented. At Hidden Canyon, in the northwestern 

part of the region, numerous sandstone beds included 

some very coarse grained sand (1-2 mm).

Throughout the region of study, the dominant size 

grade, Wentworth scale, for rocks of the Wescogame Formation is very fine grained (1/16-1/8 mm). At essentially 

all localities in eastern Grand Canyon, and at two localities—Hidden Canyon and Pigeon Wash—in the far west, 

however, at least some of the sandstone beds are dominantly fine grained (1/8-1/4 mm), and at Hermit Trail 

one sandstone sample showed medium-grained sand to be 

dominant.

Cross-stratification of 

Wescogame Formation

Characteristic features

Cross-stratification is a conspicuous feature of the 

Wescogame throughout the Grand Canyon region. It occurs both in the sandstones, ranging from fine to very fine 

grained, that form most of the unit throughout much of the 

area, and in the carbonate rocks that dominate the unit in 

far western sequences. Only the mudstones and some limestones that are interbedded in relatively small proportions
SANDSTONES 223

114° 113° 112°

36C

EXPLANATION 

Medium-grained

Fine-grained 

Very fine grained

Unit slice, (y3 quadrant), 

represents one analysis

12 Number of analyses

FIGURE K10.—Dominant size grade of particles in detrital rocks of the Wescogame Formation, Grand Canyon region, Arizona. Each unit slice (1/3 

quadrant) in a pie diagram represents the dominant grain size for one analysis from the locality indicated. ("Dominant" refers to the principal size 

grade represented by one analysis.) Arrow and miles next to a pie indicate direction and distance to actual sample locality.

among the major cross-stratified units, are flat bedded or 

appear structureless.

Much of the cross-stratification is large scale (fig. L4), 

some at Grandview Trail, Kaibab Trail, north, S B Canyon, and Twin Springs Canyon containing foresets 40-50 

ft in length. At both Grandview Trail and S B Canyon, sets 

of dipping strata measure 50-60 ft in length, and at Havasu 

and Parashant Canyons, foresets more than 60 ft long were 

recorded. Although cross-strata more than 20 ft in length 

are common in the Wescogame, medium-scale cross-strata 

(1-20 ft long) are dominant in most places, as indicated in 

table K4. Small-scale cross-strata (less than 1 ft) are very 

uncommon in these rocks and only locally occur in some 

abundance.

The principal types of cross-stratification are planar 

(figs. K11-K14; L3) with tabular and wedge varieties in 

about equal proportions, distributed without any recognizable relationship to either geographic or stratigraphic 

positions (table K5). Trough cross-strata are less common 

than either of the other types, but are more numerous than 

in the Manakacha below or the Esplanade Sandstone

above. Most strata of this type form festoon patterns and 

the troughs are shallow but wide (8-45 ft). Conspicuous 

examples of cosets containing this structure were noted 

near Topocoba Trail and in Havasu, Tuckup, and Andrus 

Canyons.

High-angle dips (20° or more) on foreset beds were dominant at 13 localities at each of which 30 random measurements were recorded. Lower angles were dominant at 

seven localities and equal numbers of high- and low-angle 

dip surfaces at four others (table K6).

Most of the cross-stratified sandstone and arenaceous 

limestone bodies (cosets) of the Wescogame are relatively 

thin compared with those in the overlying Esplanade unit. 

A majority are between 4 and 12 ft thick, although at 

Havasu Canyon a unit measuring 30 ft thick, and at Kanab 

Canyon one measuring 40 ft thick, were noted (table K5).

Cosets show a wide range in the number of superimposed 

sets included in each. They range from 1 to 11, but most 

commonly are 3 or 4 (table K5). Such compound structures 

are characteristic features in both the sandstones of eastern
THE SUPAI GROUP OF GRAND CANYON

10 15

—"0

FIGURE KIT.—Sets of planar cross-strata and trough-like cross-strata in arenaceous limestone, Wescogame Formation, Grand Canyon region, 

Arizona. A, Slope unit, Snap Canyon; 8, cliff unit, Hidden Canyon. Vertical and horizontal distances in feet.

Grand Canyon and the arenaceous limestones in the west. 

Only in a few places, as at Eminence Fault and Twentynine Mile Canyon, are the units so massive as to appear 

structureless.

The cross-stratified units of the Wescogame range from 

sandstones with considerably less than 50 percent carbonate content in eastern Grand Canyon, to highly calcareous 

sandstones mostly in the central Grand Canyon area, to 

sandy limestone with an insoluble residue less than 50 percent in the far west.

Current directions

Cross-strata in sandstones and arenaceous limestones 

of the Wescogame were analyzed statistically in order to 

determine average directions of the depositing currents.

Methods used were the same as those described for the 

Manakacha, with 30 sets being measured at each locality 

(figs. K15, K16). The results as plotted are shown in figure 

K17.

Directions of sediment transport as indicated by mean 

dip directions of cross-beds are dominantly toward the 

south, but with more of an easterly trend than in the Manakacha. The eastward trend is especially pronounced in 

averages from western Grand Canyon which attain a maximum of 42° east of south. The total spread across the 

region is 103°, which is greater than in the Manakacha but 

still relatively small.

Ripple marks in sandstone

Only a few cross-stratified sandstone beds of the Wescogame Formation exhibit foreset surfaces that are covered
SANDSTONES 225

25

I

60

T 1

_j

F HH 50-

12

-45-

7 ~

30 • '

' T.V

-150-

D

FIGURE K12.—Sets of tabular-planar, wedge-planar and trough crossstrata in calcareous sandstone of Wescogame Formation, Grand Canyon 

region, Arizona. /\, Red-brown sandstone with tabular-planar crossstrata; slope unit near Kaibab Trail, south. 6, Trough structures above 

tabular-planar cross-strata; slope unit near Kaibab Trail, south. C, Channel cut in planar cross-stratified sand, filled with horizontal shaly 

mudstone; base of cliff unit, Apache Trail above Supai village. D,

EXPLANATION

TTT

Sandstone 

Limestone 

Jasper concretions 

Shaly mudstone 

Siltstone

Tabular-planar structures forming cosets above and below limestone 

with jasper concretions; base of cliff unit, Toroweap Valley. £, Horizontal sand laminae overlying truncated top of tabular-planar set; near top of 

cliff unit in Havasu Canyon. F, Asymmetrically filled, and C, symmetrically filled trough structure in sandstone of cliff unit; Bright Angel 

Trail. Vertical and horizontal measurements in feet.
226 THE SUPAI GROUP OF GRAND CANYON

•50

10

22

-20

B

12 20

I I I I I I I I I I I I I I I I I

I I I I I I I I I I I I I I I

I I I I I I I I I I
SANDSTONES 227

i . i . i

111 ill

CE> 0? 

CD __ .

a 'CD —— " —— 'i __

48

48

10°..-

'-20°

•36

EXPLANATION

Sandy limestone 

Siltstone or mudstone 

Limestone 

Limestone concretion

FIGURE K13.—Tabular-planar, wedge-planar, and festoon cross-strata, 

Wescogame Formation, Grand Canyon region, Arizona. A, B, Sets of 

sandstone cross-strata with erosion surface between; Kaibab Trail, south. 

C, Sets of sandstone cross-strata with depositional contact; Kaibab trail, 

south. D, E, Cyclothem with units of siltstone, limestone, and crossstratified sandstone; Grand Gulch Wash (D) and Pigeon Wash (E). F, Festoon cross-strata; Grand Wash Cliffs. G, Asymmetrically filled trough 

cross-strata near base of slope unit; Kaibab Trail, south. Vertical and 

horizontal measurements in feet.
228 THE SUPAI GROUP OF GRAND CANYON

*»-. % «*»*;"„

FIGURE K14.—Cross-strata in sandstone and in carbonate rock of the 

Wescogame Formation, Grand Canyon region, Arizona. A, Wedgeplanar cross-beds with quartz grains etched out on limestone surface; 

Iceberg Canyon. B, Wedge- and tabular-planar cross-beds in limestone; 

Iceberg Canyon. C, Cross-strata of wedge-planar type in arenaceous 

limestone; Twin Springs Canyon. Scale—pencil in bottom center. D,

nqr

•rfli ,,^j^^m,il ' ^^SS^^L _*--*!- •» -in •y' '. • • T-^

i?^r^-'\--;'-^. > k'^^ar-- 'iF^ -•?...

^6*^^i 

--«'" **:#&*

' •f.%*^-*'* mf rj^%jjjig£&?-*j& m.

Contact between sets in tabular-planar cross-strata, calcareous sandstone; Fishtail Canyon near Thunder River Trail. Scale in inches. E, 

Trough structure in tabular-planar cross-strata; Kaibab Trail, south. F, 

Topset bed (below hammer) continuous with foreset bed, to left, in 

sandstone; Kaibab Trail, south.

with ripple marks. Rippled surfaces recorded during the Mostly they occur in very fine grained sandstone of the

measuring of stratigraphic sections in Grand Canyon are cliff unit, but at least one set was observed in arenaceous

of several types, including linguoid (fig. N3C), lunate (fig. limestone and one in clean siltstone. These are discussed in

N3B), and parallel-straight or parallel-sinuous (fig. N3-A). detail in chapter N under minor depositional structures.
SANDSTONES 229

SANDSTONE OF THE 

ESPLANADE SANDSTONE

Geometry of Esplanade 

sand body

The youngest and the thickest major sand body in the 

Supai Group forms the main cliff unit of the Esplanade 

Sandstone (fig. P12). In general, its form is that of a 

wedge, gradually thickening westward, where the lower 

part interfingers with limestone and dolostone of the 

Pakoon Limestone of McNair (1951) and the upper part 

merges (probably grades laterally) into siltstone and 

mudstone. Thickest parts of the sandstone body (300-400 

ft) are in the central part of the region, but whether this is 

the result of a greater amount of deposition or a lesser subsequent erosion in that area is not known. Nearly everywhere in the region deposition began with mud and silt of 

the basal slope unit, but because these red beds alternate 

upward in the section with beds of pure sand, it seems 

probable that base level rose periodically. No information 

is available on the extent of the sand body in a north-south 

direction.

Grain-size distribution in the 

Esplanade Sandstone

Analysis of grain size in sandstones of the Esplanade has 

been made for the Grand Canyon region. In addition to 

mechanical analyses from sieving more than a hundred 

selected samples (fig. K18), grain sizes for a large number 

of other samples, representing most of the sandstone units 

in each measured section, were roughly determined by a 

visual-comparison method using a binocular microscope. 

Sorting was sufficiently good in nearly all samples to determine the dominant size grade from a single analysis; a 

sample was obtained for each set or coset of strata and 

cross-strata as recognized in a measured section.

Maximum grain size

The bulk of the Esplanade is very fine sand but a few 

grains in some samples are coarse or very coarse. Very 

coarse grains were observed in sieved samples from a majority of the sand units at Andrus Canyon in west-central 

Grand Canyon (fig. K18) and also from nearby sections at 

Whitmore Wash, Toroweap Valley, and Separation Canyon and, farther south, at Picacho Butte (fig. K18). Coarse 

grains were observed in samples from 14 localities including 4 in eastern Grand Canyon and 3 to the south. 

However, a large majority of all sandstones containing 

either coarse or very coarse grains were found in westcentral Grand Canyon; none were noted in the far western 

sections.

Medium and finer size grades

Sandstone of the Esplanade contains a great preponderance of sets and cosets (290 samples, considered representative) in the very fine grained sand category (1/16-1/8 mm) 

(table K7). Dominantly fine grained sand (1/8-1/4 mm) was 

found in 35 samples at 15 localities, and mediumgrained sand (1/4-1/2 mm) was dominant (size grade containing largest amount of sand) in 9 samples from 7 localities (fig. K19).

TABLE K7.—Proportion of sets and cosets of sandstone units to 

siltstone units in each formation of the Supai Group. Dominant grain 

size (size grade with largest amount of sand) was determined by 

method of visual comparison using standard mounts under 

microscope. Figures refer to number of samples in each grade class

Esplanade1 Wescogame Manakacha Watahomigi

Siltstone ..........

Very fine grained

sandstone .......

Fine-grained

sandstone .......

Medium-grained

sandstone .......

70

290

35

9

40

114

34

1 '

93

113

22

2

75

17

4

2

Total samples. 404 189 230 98

1 Esplanade Sandstone includes Pakoon Limestone (McNair, 1951) in far western Grand Canyon, 

and a few tongues of Pakoon farther east.

Fine-grained sandstone seems to be widely scattered geographically, though it is most common in western and 

northern localities. It is largely from the main cliff unit, but 

three exceptions in central Grand Canyon represent the 

upper cliff-slope unit. Medium-grained sandstone is from 

the middle-western and western parts of the area and is 

nearly entirely from the main cliff unit. The conclusion 

based on grain-size distribution, therefore, is that most of 

the sand in the Esplanade was derived from a source to the 

north and northwest of the area under study, but that 

grain size, in general, is very uniform across the region.

Cross-stratification of 

Esplanade Sandstone

Characteristic features

The dominantly well sorted, very fine grained sandstone 

of the main cliff unit of the Esplanade is characteristically 

cross-stratified throughout most of the Grand Canyon region. Planes of cross-strata are conspicuously etched in 

relief by weathering at nearly all localities in central and
230

30 30

THE SUPAI GROUP OF GRAND CANYON 

N

30 "~~r~~~~

60 60

E W

60 60

Av. 188

30

60 60

E W

60 60

60

Av. 143

60

30

Av. 151

30 30

60 60

E W

30

Av. 190

30

60 60

E W

60

30

Av. 180 Av. 152

30 30

E W

60 60

Av. 175

30

E W

30

Av. 195

60

Av. 217
SANDSTONES 231

30

60

30

60

30

Av. 153

30 30

Av. 147

30

Av. 161

FIGURE K15.—Cross-strata dip directions, average dip direction (Av.), 

and degree of dip, plotted on polar coordinate sheets for the Wescogame Formation. Grand Canyon region, Arizona. A, House Rock Canyon; 6, Marble Canyon; C, Horsetrail Canyon; D, Bunker Trail; E, F, 

Grandview Trail; G, Kaibab Trail, south; H, Bright Angel Trail; /, Hermit 

Trail;/, Bass Trail; K, Topocoba Trail; and L, Havasu Canyon.
232 THE SUPAI GROUP OF GRAND CANYON 

N

60

E W

60 60

Av. 179

30

E W

60 60

Av. 168

60

Av. 126

30

60 60

E W

Av. 194

30 30

60 60

E W

60

Av. 192 Av. 124

30 30 30 30

60

E W

30

Av. 167

30

E W

Av. 114

30

Av. 137
SANDSTONES 233

30

60

Av. 163

60

Av. 155

Av. 155

FIGURE K16.—Cross-strata dip directions, average dip direction (Av.), 

and degree of dip, plotted on polar coordinate sheets for the Wescogame Formation, Grand Canyon region, Arizona. A, Kaibab Trail, north; 

B, Fishtail Canyon near Thunder River; C, Tuckup Canyon; D, E, 

Toroweap Valley; F, Whitmore Wash; G, Separation Canyon; H, Guano 

Cave (lower part of section); /, Guano Cave (upper part of section); ], 

Parashant Canyon; K, Snap Canyon; and L, Pigeon Wash.
234

114°

THE SUPAI GROUP OF GRAND CANYON

113° 112°

36°-

FIGURE K17.—Dip-direction vectors for cross-strata of the Wescogame Formation, Grand Canyon region, Arizona. Each arrow shows average 

direction determined from 30 measurements of cross-strata selected at random for the locality shown on map.

western Grand Canyon. In eastern Grand Canyon, for 

some reason not readily apparent, they are only weakly 

developed in various parts of the unit and many beds, 

especially in the vicinity of the Grandview, Kaibab, south, 

and Bright Angel Trails, appear massive and structureless 

or exhibit only traces of cross-stratification.

Nearly all of the cross-stratification in the Esplanade 

Sandstone is of the planar type (fig. L5), represented both 

by tabular and by wedge varieties in roughly equal 

amounts throughout the region (table K4). Horizontal or 

flat-lying laminae are not uncommon, interstratified 

among sets of planar type in most places, but in general 

they form relatively thin sets that represent a very small 

percentage of any sand body. Trough-type cross-strata are 

even less numerous than horizontal and were recorded 

from only 6 of the 32 localities studied. Mostly they form 

the characteristic pattern referred to as festoon (Knight, 

1929), and are filled with curving laminae of sand in asymmetrical pattern (fig. L5£,F).

The tabular-planar cross-strata of the Esplanade Sandstone typically form layers or sets of dipping beds that 

maintain fairly constant thickness over distances of 20, 30,

or more feet. They commonly form a vertical sequence 

(coset) in which the characteristic layers of steeply dipping 

foresets are repeated numerous times (fig. K20). In contrast, the wedge-planar sets form layers that are best described as compound because each set thickens or thins in a 

short distance, commonly forming a wedge that ranges 

from one to several feet thick within a lateral distance of 10 

ft or less. Actually no sharp line of distinction is recognized 

between the tabular and wedge types, as all sets or layers 

must thin to a vanishing point eventually; however, where 

seen in the limited exposure of an outcrop, the repeated 

layers of tabular sets and the compound patterns of wedge 

sets look very different.

Most cross-stratification in the Esplanade Sandstone is 

medium scale, with steeply dipping foresets between 1 and 

20 ft long (table K4). A moderate number of sets, however, 

at localities scattered throughout the region, contain largescale foresets (dipping strata more than 20 ft long) (fig. 

K20). Large-scale cross-stratification both at Fishtail Canyon near Thunder River Trail and at S B Canyon includes 

tabular-planar sets with dipping laminae 60 to 70 ft long; 

dipping strata 40 ft in length were recorded at Twentynine
SANDSTONES 235

114° 113° 112°

37C

> N

36C

UTAH

EXPLANATION 

Maximum grain size 

Very coarse 

Coarse 

Medium 

Fine 

Very fine

One unit represents one 

analysis

Number of samples

ARIZONA

FIGURE K18.—Maximum grain size of particles in detrital rocks of the Esplanade Sandstone, Grand Canyon region, Arizona. Each unit in a vertical bar 

graph represents the maximum grain size of one sandstone sample (arranged with coarse to fine, from top to bottom). Arrow and miles next to a bar 

indicate direction and distance to actual sample locality.

Mile Canyon, Topocoba Trail, and Tuckup Canyon. Relatively uncommon in the Esplanade are small-scale crossstrata (table K4).

Stratification cosets (as defined in McKee and Weir, 

1953, p. 383) have thicknesses that are determined in part 

by the amount of deposition in each set and in part by erosion that bevelled the upper surface of each set; their 

thickness constitutes a rough measure of the scale on which 

sedimentary processes operated in the area. This measure 

applies to both wedge- and tabular-planar types and to 

trough types. In the Esplanade Sandstone, thickness of 

cosets as determined from 3-dimensional studies of structure ranges from less than 2 ft to 33 ft (table K5). A large 

but representative coset measured at Toroweap was 33 ft 

thick and consisted of 11 sets of tabular-planar crossstrata. A second coset from the same area was only 8.5 ft 

thick, but included 5 sets of tabular-planar and 2 sets of 

wedge-planar cross-strata.

Maximum angle of dip was determined for the foresets 

of 30 cross-strata sets in the Esplanade Sandstone at each 

of 18 localities in the Grand Canyon region (table K6). In

this count, the sets containing cross-strata dipping 20° or 

more were classed as high angle; those less than 20° as low 

angle, following the terminology of McKee and Weir 

(1953, p. 386). Table K6 shows that the total number of 

high-angle foresets is about equal to the total number of 

low-angle foresets and that no regional distribution trend 

is apparent.

Current directions

Cross-stratification in the Esplanade Sandstone and 

Pakoon Limestone, western equivalent of lower part of 

Esplanade, has been measured for mean current direction 

at 22 localities (figs. K21, K22) in the Grand Canyon 

region and is shown to have a very pronounced 

southeasterly trend in average direction of dip (fig. K23). 

This trend contrasts with that of the underlying 

Manakacha and Wescogame Formations, which are 

dominantly toward the south.

Because of the similarity in type and scale of cross-strata 

and in the grain size and sorting within the several Supai
236

114°

THE SUPAI GROUP OF GRAND CANYON 

113° 112°

36°

EXPLANATION 

Medium-grained

Fine-grained 

Very fine grained

Unit slice, C/3 quadrant), 

represents one analysis

12 Number of analyses

FIGURE K19.—Dominant size grade of particles in detrital rocks of the Esplanade Sandstone, Grand Canyon region, Arizona. Each unit slice (1/3 quadrant) 

in a pie diagram represents the dominant sand size for one analysis from the locality indicated. ("Dominant" refers to the principal size grade 

represented by on analysis.) Arrow and miles next to a pie indicate direction and distance to actual sample locality.

sandstones, an explanation for the marked change in directional trends between units is not readily apparent. 

Possibly, the gradual east-west merging from sandstone 

into arenaceous limestone, in the lower two units but not 

in the Esplanade, is indicative of a major difference in the 

depositional environments, or perhaps the more easterly 

trend of the Esplanade current direction is the result of a 

new source area developed to the northwest.

The Pakoon Limestone in the westernmost part of the 

Grand Canyon is believed to be a lateral equivalent of the 

lower part of the Esplanade Sandstone, and contains similar cross-stratification in many of its arenaceous dolostone 

and limestone beds. Statistical studies were made of these 

strata at three localities and average dip directions were 

determined for them (fig. K24). The vectors indicate directions east of south—very similar to those of the Supai 

sandstones to the east and essentially the same as directions determined for Esplanade sandstones that overlie the 

Pakoon in western Grand Canyon (fig. C8).

Ripple marks in sandstone

Ripple marks are relatively scarce in the well-sorted, 

cross-bedded sandstone of the Esplanade. Extensive sets of 

ripples were found during the study of this formation only 

in Fishtail Canyon near the Thunder River Trail, in S B 

Canyon, and at Mile 16 (House Rock Canyon) in Marble 

Canyon. These ripple marks included both the lunate and 

the parallel-straight types.

A high-energy environment of deposition is inferred for 

the sandstone of this formation because of the ubiquitous 

presence of medium- to large-scale cross-stratification in it. 

The general scarcity of ripple marks, therefore, seems to be 

anomalous, as it is in sandstone of the underlying Wescogame. In both formations, a high stage of the lower flow 

regime seems to have been responsible for development of 

foresets in the sandstone, but ripple marks—characteristic 

of an early stage of the lower flow regime—apparently 

were not commonly formed in this environment.
SANDSTONES 237

FIGURE K20.—Size-scale of cross-strata in Esplanade Sandstone of 

Grand Canyon, Ariz. A, Compound cross-strata consisting of dipping 

planar sets filling shallow trough; Fishtail Canyon near Thunder River 

Trail. B, Large-scale, tabular-planar cross-strata underlying thin-bedded 

horizontal strata; Topocoba Trail. C, Large-scale, tabular-planar crossContorted structures

Contorted structures are uncommon in the Esplanade 

Sandstone and, except at one locality near Toroweap 

Valley where numerous sets of strata are contorted within 

a limited area, they must be considered atypical of the formation. The structures at Toroweap are in cross-stratified,

strata near top of formation; Fishtail Canyon near Thunder River Trail. D, 

Small-scale, tabular-planar set between sets of thin, horizontal strata; 

Kaibab Trail, south. Key in top center is about 2 in. long. E, Small-scale, 

tabular-planar set between sets of thin horizontal strata; Toroweap Point.

very fine grained sandstone (fig. K25) and seem to consist 

mainly of faults with accompanying brecciation and of 

very irregular anticlinal folds, probably the result of 

loading when the sand was incompetent. All of the contortion is within a single coset of planar cross-beds where the 

sand grains probably were in a near quicksand condition 

when contortion developed.
238

60

THE SUPAI GROUP OF GRAND CANYON 

N

~~^ so

60 60

E W

60 60

Av. 166

60 60.

E W

60 60

60

Av. 148

60

Av. 166

30

60. 60 60

E W

Av. 132

30

60 60,

E W

Av. 156 Av. 138

30

60 60

E W

60 60

Av. 144

60 60,

E W

60 60

Av. 167 Av. 130
SANDSTONES 239

60

Av. 157

30

60

Av. 160

30

60

30

Av. 166

FIGURE K21.—Cross-strata dip direction, average dip direction (Av.), 

and degree of dip, plotted on polar coordinate sheets for Esplanade 

Sandstone, Grand Canyon region, Arizona. A, Twentynine Mile Canyon; 

8, C, Bunker Trail; D, Kaibab Trail, south; £, Bright Angel Trail; F, Hermit 

Trail; C, Kaibab Trail, north; H, Shinumo Trail; /, Bass Trail; I, Fishtail 

Canyon near Thunder River Trail; K, Havasu Canyon; and L, Tuckup 

Canyon.
240

30

THE SUPAI GROUP OF GRAND CANYON 

N

__~-r-—

30

E W

60 60

Av. 139

E W

Av. 151 Av. 169

60 60 60

E W

30

Av. 178

60 60

E W

60

Av. 130 Av. 141

30 30 30

60 60

E W

30

Av. 114

30

60 60

E W

60 60

Av. 171 Av. 159

FIGURE K22.—Cross-strata dip direction, average dip direction (Av.), and degree of dip, plotted on polar coordinate sheets for the Esplanade Sandstone 

(A-F), and Pakoon Limestone of McNair, 1951 (G-/), Grand Canyon region, Arizona. A, Toroweap Valley; 6, Prospect Valley; C, Whitmore Wash; 

D, Snap Canyon; E, Pigeon Wash; F, Hidden Canyon; G, Snap Canyon; H, Grand Gulch; and /, south Hidden Canyon.
SANDSTONES 241

114° 113° 112°

37C

36°

FIGURE K23.—Dip-direction vectors for cross-strata of the Esplanade Sandstone, Grand Canyon region, Arizona. Each arrow shows average direction determined from 30 measurements of cross-strata selected at random for the locality shown on map.

Structureless sandstone

Structureless sandstone that forms massive units ranging 

from a few to 20 or more feet in thickness are not uncommon in sections of eastern Grand Canyon. Near Grandview Trail, structureless units 23 ft and 26 ft thick are recorded and near Kaibab Trail, north, a unit 21 ft thick is 

prominent. Despite the fact that at many places no trace of 

stratification can be detected in cliff faces and no evidence 

of laminae shows in thin-sections of the rock, the suspicion 

is strong that originally these units were sets or cosets of 

well-stratified sand. Evidence consists of (1) the texture 

and thickness of individual sand bodies, similar to those 

elsewhere that are well stratified, (2) some units that can be 

traced laterally into sets or cosets with well-defined crosslaminae, and (3) selected samples that show in X-ray the

weak traces of dipping foreset planes and the cross-cutting 

tunnels or borings of wormlike animals (fig. N9).

Small-scale structures in 

associated siltstone lenses

Various small-scale structures occur commonly in the 

shaly or thin-bedded silty units that form parting beds or 

lenses in sandstone of the Esplanade. Such siltstone units 

locally contain the impressions of plants, especially 

Walchia sp., thin, irregular shrinkage cracks, the tracks of 

reptiles, rain pits, and the borings or burrows of wormlike 

animals. At a few places they are associated with large cuspate-type ripple marks. These structures are especially numerous at several localities near the Kaibab Trail, north, 

and have been recorded locally from other places throughout the region.
242 THE SUPAI GROUP OF GRAND CANYON

114°

37C UTAH

ARIZONA

20 30 MILES

REFERENCES CITED

Alien, J.R.L., 1963, Asymmetrical ripple marks and the origin of waterlaid cosets of cross-strata: Liverpool and Manchester Geological 

Journal, v. 3, p. 187-236.

Folk, R. L., 1968, Petrology of sedimentary rocks—University of Texas 

Geology 370K, 383L, 383M: Austin, Texas, Hemphills, 170 p.

Knight, S. H., 1929, The Fountain and the Casper Formations of the 

Laramie Basin: Wyoming University Publications in Science, Geology, v. 1, p. 1-82.

McKee, E. D., 1940, Three types of cross-lamination in Paleozoic rocks 

of northern Arizona: American Journal of Science, v. 238, p. 811-824.

McKee, E. D., and Weir, G. W., 1953, Terminology for stratification and 

cross-stratification in sedimentary rocks: Geological Society of 

American Bulletin, v. 64, p. 381-390.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

Payne, T. G., 1942, Stratigraphical analysis and environmental reconstruction: American Association of Petroleum Geologists Bulletin, 

v. 26, no. 11, p. 1697-1770.

Reiche, Parry, 1938, An analysis of cross-lamination—The Coconino 

Sandstone: Journal of Geology, v. 46, no. 7, p. 906-932.

Shotton, F. W., 1937, The lower Bunter sandstones of North Worcestershire and East Shropshire: Geological Magazine, v. 74, no. 882, 

p. 547-550.

Wentworth, C. K., 1922, A scale of grade and class terms for clastic sediments: Journal of Geology, v. 30, no. 5, p. 377-392.

FIGURE K24.—Dip-direction vectors for cross-strata of the Pakoon 

Limestone (McNair, 1951), western Grand Canyon region, Arizona. 

Each arrow shows average direction determined from 30 readings of 

cross-strata selected at random for each locality shown on map.
SANDSTONES 243

FEET 

20

05 1 0 1.5 20

EXPLANATION 

Sandstone

^^H Mudstone

FIGURE K25.—Small- and medium-scale cross-strata and contorted 

bedding in the Esplanade Sandstone, Grand Canyon, Ariz. A, Contorted beds showing faulting, brecciation, and folding on small scale; 

Toroweap Point. 8, Contorted beds illustrating complex structures 

resulting from penecontemporaneous deposition, erosion, and warping; Toroweap Point. C, Contorted beds probably resulting from local 

loading to produce fold and displacement of strata; Toroweap Point. 

D, Low-angle, wedge-planar and tabular-planar cross-strata, middle

of Esplanade; Toroweap Point. £, Coset of small-scale tabular-planar 

cross-strata; Andrus Canyon. F, C, Low-angle wedge-planar crossstrata showing local penecontemporaneous warping and erosion; 

Toroweap Point. H, Compound cross-strata with trough-filling 

consisting of horizontal mud and sand beds; Prospect Valley. /, 

Small-scale tabular-planar, wedge-planar, and horizontal bed of 

sand; Hermit Trail. I, Compound-planar and horizontally bedded 

sandstone; middle of Esplanade Sandstone; Toroweap Point.

THE SUPAI GROUP OF GRAND CANYON

ENVIRONMENT OF DEPOSITION 

OF SANDSTONE BODIES

Chapter L 

By EDWIN D. McKEE

Contents

Historical review ... ..............

Characteristics of marine and fluvial cross-strata .................

Nearshore marine stratification . ,....,. t ..............

Fluvial stratification ... .. . . . . ...........

Transitional marine to nonmarine stratification . ..........

Some diagnostic attributes of cross-stratified sands ....... .....

Abundance and diagnostic features of planar cross-strata .....

Distribution and abundance of trough cross-strata ...........

Associated horizontal and low-angle cross-strata ...........

Small-scale cross-stratification distribution .........

Azimuth patterns of paleocurrent directions . ............

Distribution pattern of size grades in sand ...............

General scarcity of normal ripple marks ..... . .....

Gradation from calcareous sandstone to arenaceous limestone

Associated organisms—plants and animals .................

Associated evaporites . . .... ..................

Conclusions regarding sandstone facies .....................

The Watahomigi Formation .. ......................

The Manakacha Formation ....... .....

The Wescogame Formation ...........................

The Esplanade Sandstone ...................... .......

References cited ..........................................

Page

247

247

247

247

248

248

249

249

253

256

256

257

257

257

258

260

260

260

260

261

261

261

245
246 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Table

Page

FIGURE LI. Sketches of cross-strata in cliff unit of the Manakacha Formation ...................... 251

L2. Maps showing percentage of cross-strata that are trough type in sand bodies of each formation of the Supai Group ................................................... 252

L3. Sketches of cross-strata, wedge-planar and trough types, in sandstone of the Wescogame

Formation ....................... ...................................... 253

L4. Photographs showing large-, medium-, and small-scale cross-strata in sandstone of the

Wescogame Formation ...................................................... 254

L5. Photographs showing types of cross-strata in the Esplanade Sandstone ................. 255

Page

TABLE LI. Size determinations for some megaripples and sand waves responsible for foreset crossstrata ..................................................................... 250
ENVIRONMENT OF DEPOSITION 247

HISTORICAL REVIEW

Interpretation of the environment of deposition of the 

Supai Group was first considered in detail and discussed 

by Schuchert (1918, p. 357) when studying the "Carboniferous of Grand Canyon" along the Hermit Trail. Largely 

because of the association of mud cracks, rain pits, amphibian tracks, and impressions of land plants, he concluded that the Supai, as developed in that area, was "of 

fresh-water origin on a delta flood-plain of a river or rivers 

fronting the sea." He further stated that basal beds containing oolites "may have been formed under brackish 

water, but elsewhere the Supai is a typical series of continental floodplain deposits accumulated on a subsiding area 

under a semi-arid climate."

Recognition of a terrestrial genesis for the Supai was 

given considerable support through the studies of fossil 

plants made by David White in the late 1920's (White, 

1927, 1928, 1929). Although the work by White was mainly on the overlying Hermit Shale, which seems unquestionably of fluviatile origin, many observations in the Supai 

led him to conclude (White, 1929, p. 10) that "the upper 

and middle parts* **are terrestrial—laid down on an old 

floodplain." Thus, the Supai Group came to be recognized 

during the first half of the present century as a classic example of deposition in a continental environment, based 

on evidence from a limited area in eastern Grand Canyon 

and from a few horizons only, in that area.

Starting with the discovery of numerous marine invertebrate fossils in the Watahomigi Formation at Toroweap 

Point in the early 1940's and followed by other unequivocal evidence of a nonterrestrial environment, from 

various parts of the region and at numerous horizons, a 

strong case for the marine origin of the Supai gradually 

developed with the detailed studies of recent decades.

Attempting to assess the evidence for and against a 

marine or terrestrial environment, it now is clear that no 

single simple explanation is possible. The Supai Group not 

only consists of sequences of distinctive facies of equivalent age, but also represents a number of transgressions so 

that both land and sea deposits form a complex horizontal 

and vertical pattern. The end members in this pattern— 

strictly marine and strictly continental facies—are relatively easy to recognize by various diagnostic features as 

discussed in chapter I on transgressions and regressions. 

The facies are represented primarily by carbonate rocks 

and associated marine faunas at one extreme, and by mudstones and siltstones with plants and subaerial structures at 

the other. But the bulk of the strata between these extremes 

in the Supai—the dominantly cross-stratified sandstones 

with few fossils—can not easily be interpreted. Their 

genesis constitutes the principal subject matter of this 

chapter.

CHARACTERISTICS OF 

MARINE AND FLUVIAL 

CROSS-STRATA

The principle that down-current migration of megaripples (aqueous dunes) is responsible for the development of 

most medium- and large-scale cross-stratification is well 

established. This has been shown to apply to meandering 

river systems (Frazier and Osanik, 1961; Alien, 1965; Bernard and others, 1970), to braided river systems (Williams, 

1968, 1971; Smith, 1970; Collison, 1970), to nearshore 

sand bodies (Clifton and others, 1971; Davidson-Arnott 

and Greenwood, 1974), and to several other environments. Cross-strata formed from megaripples occur nearly 

everywhere that bedforms commonly referred to as sand 

waves transport sediment loads down-current. Straightcrested (transverse) megaripples form the planar type 

cross-strata, whereas lunate and linguoid megaripples 

develop into medium- or large-scale, trough cross-stratification (Alien, 1965; Clifton, 1976, p. 143).

Nearshore marine stratification

Characteristic sedimentary structures of sand bodies in 

nearshore coastal areas have been examined and documented by several detailed studies of recent years. Diagnostic stratification of a high-energy, nonbarred coast as 

represented by nearshore areas in Oregon and Washington 

were studied and described by Clifton (1976). Structures of 

a low-energy barrier-bar shoreline in New Brunswick, 

Canada, have been recorded and illustrated in the works of 

Davidson-Arnott and Greenwood (1974; 1976). These 

studies provide considerable information concerning 

criteria by which the nearshore marine environments 

should be recognizable in ancient sediments.

Fluvial stratification

The principal types of fluvial systems commonly recognized in modern sand environments are the meandering 

stream and the braided stream. Sedimentary structures 

formed in both of these types, like those of nearshore 

marine sands, contain an abundance of planar cross-strata 

resulting from migrating sand bodies. Fluvial sands, 

however, also include in many places large-scale trough 

cross-strata. Additional characteristic features of a fluvial 

sand environment that help to distinguish these deposits 

are horizontal strata of the upper flow regime and 

migrating ripple or climbing ripple structures of lower 

energy conditions.

Structures characteristic of meandering river systems 

have been described by numerous geologists, for example
248 THE SUPAI GROUP OF GRAND CANYON

Sundborg (1956), Harms, MacKenzie, and McCubbin 

(1963), McGowen and Garner (1975), and Bernard and 

others (1970). Models of point bars, which are the principal units of deposition through lateral and downstream 

accretion, have been developed by Bernard and Major 

(1963), Alien (1965), and others. Thus, the process of sedimentation through erosion along concave banks and deposition on convex points to form a migrating sand body, 

apparently is well recognized. Most mud and silt deposits 

are restricted to bordering flood basins and levees.

In the point-bar models, referred to above, two features 

useful for recognition are suggested: (1) upward fining of 

sediment, and (2) a characteristic succession of stratification consisting of, in ascending order, trough crossstratification, horizontal lamination, and ripple structures. 

However, point bars of other types have been recorded as, 

for example, deposits of the Colorado River in Texas, and 

the Amite in Louisiana described by McGowen and Garner 

(1975) in which "no systematic upward change in grain size 

is apparent" and the vertical sequence of sedimentary 

structures differs from that of the standard models.

Summarizing the characteristic features of meandering 

stream deposits that might be useful criteria in the recognition of ancient fluvial systems of the meander type, the 

following are suggested by Walker (1976, p. 101):

1. Commonly, but not necessarily, a floor of lag gravel 

with associated plant debris and trash.

2. Large trough cross-strata (as much as 3 ft thick) formed 

mostly from sinuous crested dune sands or megaripples.

3. Small trough structures formed from normal ripple 

migration in sand.

4. Horizontal laminations at various places in the sequence, resulting from extra-high current velocities or 

shallowing depths.

5. Fine sediments, such as silts and clays, deposited during 

overbank flooding to form vertical accretion deposits 

on the flood plains or filling abandoned channels, lake 

basins, and other depressions. These strata consist 

largely of small-scale ripple structures and flat beds 

formed from settling. They may contain root traces or 

caliche.

The braided stream environment differs from the meander-type largely because of its basic controls, which are 

high gradient, noncontinuous discharge rate, unconfined 

flow, high ratio of bed load to suspended load, and weak 

development of levees (Brown, 1973, p. 12). These controls characteristically bring about a high sand-mud ratio, 

a wide rather than narrow sand body, and a straight rather 

than meandering course. Although typically developed in 

upstream areas (Brown, 1973, figs. 8 and 9), braided 

streams may also form in coastal areas as fan deltas where

mountains are nearby or in regions of aridity where 

vegetation is sparse.

Sedimentary structures of braided stream systems as described by Off (1963), Smith (1970), and Williams (1968) 

are primarily those of migrating transverse bars or sand 

waves, of longitudinal bars, and of channel-fill deposits. 

The distinguishing features of the structures according to 

Brown (1973, p. 13) are (1) few varieties of stratification, 

(2) mostly horizontal strata, tabular-planar cross-strata 

and (or) trough cross-strata, (3) rare ripple cross-strata, 

(4) high proportions of sand, (5) multilateral sand bodies 

with high ratios of width-thickness, and (6) no definite 

trends in vertical variation of grain size or sedimentary 

structure.

Proportions of the various types of cross-strata in braided 

streams apparently vary widely with different environments and geographic settings. An increase in the ratio of 

cross-stratification to horizontal stratification occurs 

downstream along the Platte River in Nebraska, U.S.A. 

(Smith, 1970). An abundance of large-scale trough crossstrata in channel-sand deposits in the piedmont plain of 

South Australia is recorded by Williams (1968).

Transitional marine to 

nonmarine stratification

Environments intermediate between nearshore marine 

and fluvial are estuarine, tidal delta, and channel-mouth 

bar, in which sand deposits show some features of the sea 

and some of the land. Such mixtures of marine and continental deposits commonly occur as extensive areas of 

large sedimentation and probably account for many accumulations in the geologic record.

SOME DIAGNOSTIC 

ATTRIBUTES OF 

CROSS-STRATIFIED SANDS

Sandstone facies in each of the four formations of the 

Supai Group are examined in this study by analyzing for 

each unit the information available concerning 10 selected 

attributes of the rock. It was hoped that evidence would be 

procured in this way to distinguish between, first, the continental and the marine sands, and second, between meander-belt and braided-stream environments in the continental deposits and between those formed as barrier bars, 

estuaries, nearshore marine deposits and tidal deltas in the 

marine deposits. The attributes of the various sandstones 

to be discussed and interpreted on the following pages are:
ENVIRONMENT OF DEPOSITION 249

1. Abundance and diagnostic features of planar crossstrata.

2. Distribution and abundance of trough cross-strata.

3. Associated horizontal and low-angle cross-strata.

4. Distribution of small-scale cross-strata.

5. Azimuth patterns of paleocurrent dip directions.

6. Distribution pattern of size grades in sand.

7. General scarcity of normal ripple marks.

8. Gradation from calcareous sandstone to arenaceous 

limestone.

9. Associated organisms—plants, animals. 

10. Associated evaporites.

Abundance and diagnostic 

features of planar cross-strata

By far the most abundant structure in sand bodies of the 

Supai Group is planar cross-stratification of both tabular 

and wedge type in roughly equal proportions (table K4). 

The reason for the difference in form between the tabular 

and wedge varieties is not clearly understood, but because 

the horizonal and sloping surfaces that distinguish them 

might have some important significance not yet recognized, the two were separated in field counts and investigations. Here they will be treated together under the name 

of planar cross-strata.

The abundance of planar cross-strata in the Manakacha 

and Wescogame Formations, and Esplanade Sandstone can 

be considered normal for sand-wave deposition in any of 

numerous environments. In an attempt to discover which 

environment is represented by the sand bodies in each of 

these formations, various attributes of the cross-strata 

were studied statistically throughout the region. These include: (1) length of foresets (table K4)—small scale, < 1 ft, 

medium scale, 1-20 ft, large scale, > 20 ft; (2) number of 

sets in a vertical sequence (table K5); (3) thickness of coset 

(table K5); (4) foreset dip degree (table K6)—high angle, 

20° or more, low angle < 20°.

Perhaps the most potentially significant of the various 

attributes of the cross-strata examined in the upper three 

formations of the Supai (Manakacha, Wescogame, and Esplanade) is the length of the foresets, referred to as the 

scale of the cross-strata. As shown in table K4, extremely 

few small-scale structures (ripple laminae, climbing ripples) were noted in any of these formations, although a 

moderate number was found in the underlying Watahomigi. Medium-scale cross-strata were approximately twice 

as numerous as large-scale in all three formations. Most 

important, however, is the number of sets in the Manakacha containing outstandingly long foresets (30-100 ft), 

especially in the central Grand Canyon area. It seems 

doubtful that planes of this magnitude could represent the 

fronts of migrating megaripples; the alternative, that they

were formed as foresets of small (Gilbert-type) deltas 

seems more likely.

In order to obtain an appreciation of the dimensions of 

foresets developed by the movement of sand waves in 

various modern environments, a search was made in the 

literature for foreset measurements. Very few data were 

found for dip surfaces of cross-strata, but measurements of 

sand waves and (or) megaripples were numerous and are 

believed to approximate dimensions of foresets in crossstrata formed by them (table Ll).

Distribution and abundance 

of trough cross-strata

The abundance and presence or absence of trough crossstrata within sand bodies of the Supai Group is considered 

important evidence bearing on the depositional environment of these strata. Trough-type structures are distinctive 

and relatively easy to recognize. Furthermore, in recent 

years many observations have been made on modern 

analogs so that today a considerable fund of information 

has accumulated relative to the distribution, variation, and 

genesis of trough structures in sand bodies.

Trough cross-stratification is the product of deposition 

from migrating megaripples or subaqueous dunes of lunate 

and linguoid form or of sinuous-crested ridges that are 

compound varieties of these (Alien, 1965; Williams, 1971; 

Walker, 1976, p. 105). The relative abundance or the 

absence of this structure, therefore, should be an indication of the type of environment in which a particular sand 

body was developed. Although megaripples are known to 

form in many different environments, they are much more 

common in some facies than in others and differ greatly in 

size and shape.

Fluvial environments, in general, are favorable to the 

forming of trough cross-stratification (Alien, 1963a, p. 

219), but the meandering stream, because of its point-bar 

development, is especially characterized by this structure. 

The abundance of trough cross-strata in this facies was emphasized by Frazier and Osanik (1961, p. 121) in their 

description of an exposure in the Mississippi River delta 

where they state: "The entire exposed section is characterized by festoon (trough) crossbedding—the only type of 

bedding present." Further, Bernard and Major (1963, 

p. 350), in a description of the recent meander belt deposits 

of the Brazos River, Texas, stated that the normal occurrence of festoon or trough structure constitutes one of four 

zones in each point bar.

Aside from its abundance, trough cross-strata formed by 

meandering streams should be recognizable because of the 

common association with it of leaves, sticks, and other 

trash and the accumulation of lag gravel on the scour 

floors (Frazier and Osanik, 1961, p. 136; Bernard and
250 THE SUPAI GROUP OF GRAND CANYON

TABLE L1.—Size determinations for some megaripples and sand waves responsible for foreset cross-strata

[Leaders (—) indicate no data; max., maximum]

Environment

Nearshore marine .

Do. .....

Do. .....

Barrier islands ....

Do. .....

Do. .....

Do. .....

Tidal embayment .

Do. .....

Do. .....

Do. .....

Do. .....

Do. .....

Do. .....

Do. .....

Estuarine ........

Braided river .....

Ephemeral river . .

Locality

Oregon coast, U.S.A. ....

......... do. .........

......... do. .........

Georgia coast, U.S.A. ....

......... do. .........

......... do. .........

......... do. .........

Bay of Fundy, Canada ....

......... do. .........

......... do. .........

......... do. .........

......... do. .........

......... do. .........

......... do. .........

......... do. .........

St. Lawrence River, Canada

Tana River, Norway ......

Central Australia ........

Reference

source

Clifton and others (1971)

.......... do. ..........

.......... do. ..........

Hovt (1967) ..............

.......... do. ..........

.......... do. ..........

Hoytand Henry (1967) .....

Swift and McMullen (1968) . .

.......... do. ..........

.......... do. ..........

Dalrymple and others (1978) .

.......... do. ..........

.......... do. ..........

.......... do. ..........

.......... do. ..........

D'Anglejan (1971) .........

Collinson (1970) ..........

Williams (1971) ...........

Terminology

of reference

structure

Megaripples ...........

........ do. ........

........ do. ........

Megaripples ...........

Sand waves ...........

Sandwaves ............

Megaripples ...........

Sand waves, 1st order . . .

Sand waves, 2nd order . .

Linguoid ripples ........

Ripples ...............

Type 1 megaripples .....

Type 2 megaripples .....

Megarippled sand waves .

Rippled sand waves .....

Submarine sand dunes . .

Dunes ...............

Megaripples ...........

Amplitude

(in feet)

0.3 - 1

.1 -

.1 -

3

12

17

3 (max.

—

...

<.16

.16- 1

.16- 2

.5 -11

.5-2

18 -24

.66

(max. 1.

.3 - 1

.0

.4

.6

Wavelength

(in feet)

0.05- 1.0

1

20

300

.1 - 3.5

- 2

- 40

Subdivision

Outer rough facies.

Outer planar facies.

Inner rough facies.

Tidal currents.

Channel inlets (crest length 600 ft).

Offshore tidal channels.

12)

.6

.3

.2

.5

3)

.2

Migrating channels among barriers.

30

3

<3

<1

33

16

180

3

3

- 90

- 30

.3 - 82

16- 46

-705

- 82

River channel for 4-5 km.

- 60

- 15

(max. 30)

Barred coast .....

Do.

New Brunswick, Canada . .

......... do. .........

Davidson-Arnott and

Greenwood (1976).

.......... do. ..........

........ do. ........

........ do. ........

.6

.6

...

—

Bar crest.

Rip channel.

others, 1970, fig. 21). Additional evidence may be furnished 

by the upward gradation from troughs to small-scale or 

climbing-ripple structures, to laminated clays and silts of 

channel abandonment at the top. In some places, natural 

levee sediments may overlie the point-bar sequence.

But trough structure is by no means restricted to point 

bars of meandering streams. Braided stream deposits of the 

Platte River, Colorado and Nebraska, are described by 

Smith (1970, p. 3002) as containing "varying amounts of 

trough and planar cross-stratification" in longitudinal bars 

and "trough cross-strata" in upstream parts of horizontal 

bars. Ephemeral streams of central Australia, according to 

Williams (1971, p. 21), contain "large-scale trough crossstratification***^ channel sands beneath trains of largescale ripples, cosets erosively overlying older flood 

deposits. The [trough] structure formed about 60 percent 

of the 1967 deposits." Many other records of large trough 

structures, involving various types of streams, but always 

related to megaripple migration, have been described in 

the literature.

Trough cross-strata in sand of the marine nearshore 

zone, as described by Clifton, Hunter, and Phillips (1971, 

p. 656) for the Oregon Coast, is developed in several of the 

"facies" or belts that parallel the shore at different depths. 

Relatively small troughs form in the "inner rough facies" or 

surf zone and are parallel to the strand. In the "outer rough 

facies," or buildup zone, lunate megaripples produce crossstrata with a trough geometry. These trough-structures, 

with landward-facing slipfaces, seem to be very irregular

(weakly developed festoon patterns) and are restricted to a 

very narrow belt "30-120 m wide" (10-40 ft), bounded by 

facies with different hydrodynamic controls and containing structures of contrasting types.

In the Supai Group as a whole, trough cross-strata may 

be classed as uncommon, and relatively little of it shows 

good festoon development. From the standpoint of interpreting depositional environments, however, the distribution of this structure for each formation and also for each 

principal geographic area, must be considered separately. 

Accordingly, the proportions of trough to other types of 

cross-strata have been calculated with respect to both time 

and space.

The Watahomigi is not discussed here in connection 

with types of cross-strata because, as already pointed out, 

it contains only very small sand bodies. These have some 

small-scale cross-stratification, but medium- to large-scale 

types have not been recorded.

The Manakacha, in contrast, contains extensive, thick 

units of sandstone that are highly cross-stratified as described and illustrated (fig. LI) and in chapter K (figs. K5, 

K6). Medium- and large-scale trough cross-stratification is 

absent in the Manakacha Formation (table K4). Sandstone 

structure in this formation consists of medium- to largescale planar cross-beds of both tabular and wedge type, and 

of a moderate amount of horizontal stratification.

The lack of trough-type cross-strata in Manakacha sandstone bodies is believed to constitute strong evidence of a 

nonfluviatile origin for most of this formation in the Grand
ENVIRONMENT OF DEPOSITION 251

^-r-T--:~T-"-~T-r-"'~: T'ri~r 7T:"r-"1TT'r- •. -T- : -T- : -T- •' 1"- ; T' ; T- • --r--p--T^

.'. .| . .T-r1-

T"~T""T

-I- -1 • 1 • • • I

^ y I I • • I

-110.5-

EXPLANATION

Cross-stratified 

Sandstone

Limestone

Arenaceous 

limestone

Calcareous deepred siltstone

—————————————————————————————— 90 ————————————————————————————————*|

B

FIGURE L1 .—Cross-strata in cliff unit of the Manakacha Formation in Grand Canyon, Ariz. A, Tabular-planar set in sequence of strata including siltstones, 

mudstones, arenaceous limestones, and limestones; Bright Angel Trail. 8, Coset composed of three tabular-planar sets of sandstone cross-strata; 

Havasu Canyon. Vertical and horizontal distances in feet.

Canyon area. The large sandstone body involved contains 

mostly planar structures and grades into arenaceous limestone with similar structures to the west. This is believed to 

indicate deposits of a shallow-water, coastal area. 

The Wescogame Formation, unlike the Manakacha, includes a large proportion of trough cross-strata within 

sandstone units. In fact, considerably more trough structures occur in this formation than in any other of the Supai 

Group. In eastern Grand Canyon they represent 22.4 percent of all cross-strata in the Wescogame, in central Grand
252 THE SUPAI GROUP OF GRAND CANYON

Canyon 50.0 percent, and in western Grand Canyon 27.0 

percent (fig. L2).

FIGURE 12.— Percentage of cross-strata that are trough-type in 

sand bodies of upper three formations of Supai Group, Grand Canyon 

region, Arizona.

Much of the trough cross-stratification in the Wescogame, especially in the central part of Grand Canyon, is 

large-scale, forming wide, shallow troughs that make a 

typical festoon pattern (figs. K11-K14; L3, L4). Mostly, 

the troughs are filled symmetrically, but some of them 

display very asymmetrical patterns of gently curving 

laminae that are tangential at their bases. Groups of festoon or trough structures in some places compose entire 

units or cosets, 6-12 ft thick (table K5), with few other 

structures associated, but elsewhere they occur in various 

combinations with wedge or tabular-planar sets.

The interpretation assigned to the widespread development of trough-type structures in the Wescogame throughout the Grand Canyon embayment is that deposition of the 

sand bodies was in large part by sand waves of a fluvial 

system. Furthermore, evidence seems to favor a braidedstream environment rather than one of meander type, because no ripple laminae or climbing ripple structures are 

known to overlie the troughs, and because neither pebble 

lag nor plant debris seem to be associated with them (Frazier and Osanik, 1961).

Additional structures support a general fluvial environment hypothesis for the Wescogame. These structures consist of: (1) reactivation surfaces (Harms and others, 1975, 

p. 51), present in various localities, (2) bottomsets and topsets, as well as foresets (fig. K14F), preserved locally and 

indicating deposition of small Gilbert-type deltas, and (3) 

clearly preserved footprints (figs. E21, E22) of quadrupeds 

climbing up foreset surfaces.

In the Esplanade Sandstone, the main or cliff unit is 

characterized throughout by cosets of strata and crossstrata as much as 30 or more feet thick (table K5). Included 

within the cosets are numerous thin units of flat-lying 

or horizontal beds that are interpreted as deposits of the 

upper flow regime; however, a great preponderance of all 

structures are planar-type cross-strata with wedge and 

tabular forms (table K4) in about equal proportions (figs. 

K20; L5). Trough cross-strata occur in numerous places, 

but cannot be considered common anywhere.

Origin of the Esplanade Sandstone seems less easy to 

interpret on the basis of cross-strata than either the 

Manakacha, in which trough structures are absent, or the 

Wescogame, in which they are numerous. Tabulations 

made at various sections throughout Grand Canyon indicate that about 8.0 percent of structures in the western 

part of the region are trough type; about 5.1 percent in the 

central part and only 3.5 percent in the eastern part are of 

this type. Thus, the amount of lunate or linguoid megaripples represented in all parts of the region is not sufficiently 

great to form compelling evidence of a fluvial environment. Conclusions concerning the genesis of this sand 

body obviously must depend on evidence other than that 

of cross-stratification, and this evidence is presented later.
ENVIRONMENT OF DEPOSITION 253

T T

12

_L

45-

5

i

••'.••.••"••.'.'.-T

•'•:-••"--" I 

I

12

1

30-

10

_L

40

D

24

1

4

T

EXPLANATION

Sandstone 

Cross-stratified 

Flat-bedded

FIGURE L3.—Cross-strata, wedge-planar and trough types in sandstone of Wescogame Formation: A, Cliff unit in Tuckup Canyon; trough 

cross-strata. B, Baseof cliff unit, Topocoba Trail; trough structure forming 

festoon cross-strata. C, Middle of cliff unit, Topocoba Trail; mixed 

tabular-planar, wedge-planar, and trough cross-strata types. D, Top of

Associated horizontal and 

low-angle cross-strata

Although cross-strata of several types form the dominant structure of sandstone bodies in the Manakacha, 

Wescogame, and Esplanade Formations, horizontal or flatlying strata are not uncommon, especially in the Esplanade. These strata mostly form sets that range in thickness 

from a few inches to a few feet and occur above (fig. L4), 

below (figs. L4B; K20B), or adjacent to (figs. K5A, K12C) 

sets of cross-strata. They are formed in arenaceous limestones as well as in sandstones (fig. K20D, £).

The usual interpretation of horizontal strata such as 

those that occur in the widespread sandstone bodies of the 

Supai is that they were formed in the upper flow regime, in 

contrast to associated megaripple structures that represent

cliff unit, Andrus Canyon; festoons formed by shallow overlapping 

troughs. E, Cliff unit near Topocoba Trail; asymmetrically filled trough 

structure overlain by wedge-planar cross-strata. F, Cliff unit near Bright 

Angel Trail; wedge-planar structure. Vertical and horizontal 

measurements in feet.

the lower flow regime (Simons, Richardson, and Nordin, 

1965). This combination of strata suggests a high-energy 

environment in which water movement fluctuated back 

and forth from one flow regime to the other.

The horizontal structures not only occur in various 

marine environments (Clifton and others, 1971, p. 658), 

but also in fluviatile settings (Williams, 1971, p. 32; Singh, 

1972, p. 312). Thus, considered alone, they probably are 

not diagnostic of any one environment, but in a vertical sequence and in relation to other bedf orms they may mean a 

great deal.

Because the type of structure (horizontal or planar crossstrata) is largely a function of stream flow or of current 

and tide strength at a particular stage, the proportions of 

each type vary widely in most environments. Horizontal
254 THE SUPAI GROUP OF GRAND CANYON

stratification is the main structure in longitudinal bars 

along the Platte River in Nebraska, U.S.A., but transverse 

bars contain very few horizontal strata and are composed 

mainly of planar and trough cross-strata (Smith, 1970, 

p. 3002). Rat bedding with parting lineation is estimated 

by Williams (1971, p. 32) to account "for no more than 5 

percent of the flood deposits" studied in central Australia,

FIGURE 14.—Large-, medium-, and small-scale cross-strata in sandstone of the Wescogame Formation, Grand Canyon region, Arizona. A, 

Trough structure in large-scale cross-strata of Wescogame cliff unit; Marble Canyon. 6, Large-scale, tabular-planar cross-strata (foresets about 35 

ft long); Tobocoba Trail. C, Medium-scale, tabular-planar cross-strata; 

Kaibab Trail, south. D, Large-scale tabular-planar cross-strata; Hualapai 

Trail to Supai Village. E, Small-scale cross-strata formed by climbing ripple structures that indicate relatively low-energy environment with 

abundance of available sand; Iceberg Canyon.

but elsewhere he stated that along the Finke River it was 

"the dominant structure in flood deposits" among fine to 

medium sands. Even more extreme are results of the Bijou 

Creek flood in Colorado (McKee, Crosby, and Berryhill, 

1967, p. 829) where an estimated 90-95 percent of all 

deposits were horizontal strata.
ENVIRONMENT OF DEPOSITION 255

^^c-ss?^^^^^., ^^^>^ ..^,,>--" *•« '-*•

Clearly, a great disparity exists in the amount of horizontal stratification formed under different stages of any 

depositional agent. This fact is shown for stream deposits 

cited above and is illustrated by several studies of nearshore marine deposits. For this reason, low percentages of 

horizontal strata found in the Manakacha and Wescogame 

Formations and the relatively small amount in the EsplaFIGURE L5.—Types of cross-strata in the Esplanade Sandstone of 

Grand Canyon, Ariz. A, Trough cross-strata, medium scale; Andrus 

Canyon. 6, Trough cross-strata, medium scale, lower part of formation; Hidden Canyon. C, Tabular and wedge-planar cross-strata, 

medium scale; Fishtail Canyon near Thunder River Trail. D, Tabularplanar cross-strata, medium scale; Apache Trail, Havasu Canyon. E, 

Trough cross-strata above basal conglomerate; Topocoba Trail. F, 

Trough cross-strata, lower part of formation; Topocoba Trail.

nade Sandstone seem to show only that these sandstones 

were formed very largely under conditions of lower flow 

regime, whether in streams or in marine environments.

The flat, uniform, low-angle (2-10°) stratification characteristic of foreshore beaches is very distinctive and has
256 THE SUPAI GROUP OF GRAND CANYON

been described in detail by numerous geologists (Thompson, 1937; McKee, 1957, p. 1706). These structures should 

be readily recognized in the Supai Group, especially if in 

juxtaposition with backshore deposits that likewise have 

distinctive structure patterns, but none have been recognized during this study of the sandstone bodies.

Small-scale cross-stratification 

distribution

The term "small scale" as applied to cross-strata in this 

investigation refers to structures measured in inches, rather 

than in feet. Thus, it applies to ripple lamination, climbing 

ripples (ripple drift), flaser bedding, lenticular bedding, 

small-scale festoon patterns, and probably a few others. 

Because small-scale structures are the product of relatively 

low energy and represent an early stage of the lower flow 

regime (Simons and Richardson, 1961), they cannot normally be expected in association with those sand bodies of 

the Supai Group formed from megaripples and sand 

waves, except where waning stages are represented.

The modern environments from which small-scale ripple 

cross-strata have been reported as abundant are mostly 

associated with river flood plains such as the Colorado 

(McKee, 1938, 1939), the Rhone and Mississippi (Van 

Straaten, 1959, p. 213), the Indus (McKee, 1966), and 

many others. Such structures also occur in the upper parts 

of pcfint bars as on the Mississippi (Frazier and Osanik, 

1961), the Gomti River, India (Singh, 1972, p. 310), and 

the Brazos River (Bernard and others, 1970). Small-scale 

ripple festoons are illustrated from the Red River, Louisiana, by Harms, MacKenzie, and McCubbin (1963), and on 

bar crests of offshore bars in New Brunswick (DavidsonArnott and Greenwood, 1974). Perhaps the most extensive 

and impressive examples of ripple lamination to be recorded, however, are from topset, foreset, and bottomset 

areas of an "esker delta" bordering the Yoldia Sea in 

Finland (Aario, 1971, 1972). Here, deposition was mainly 

from suspension and occurred in deep sea water. Variations and vertical successions of sedimentary structures in 

this environment show many pulsations in the regime of 

melt water.

Other types of small-scale cross-strata for which the environment of deposition has been identified are the "flaser 

and lenticular" bedding types. These are related to the 

"alternation of current or wave action and slack water" according to Reineck and Wunderlich (1968, p. 103). "The 

preferred environments are areas where a change takes 

place between slack water and water turbulence. The 

genesis is related to tidal rhythms***"

In interpreting sandstones of the Supai Group, the question arises as to why small-scale cross-strata are, in 

general, so uncommon. The major sandstone units of the 

Supai are composed mostly of medium- to large-scale

cross-strata representing deposits of megaripples and of 

high energy. Two examples (figs. L4E; N2A) of ripple 

laminae associated with the high-energy sandstones are 

from the Wescogame at Toroweap Point and at Iceberg 

Canyon where it is considered to be of fluvial origin. Most 

examples of climbing ripples are in the lower part of the 

Watahomigi (figs. N1A, B, C) where they are among siltstones and other fine-grained rocks resulting from deposition in a low-energy environment.

Azimuth patterns of 

paleocurrent directions

Mean dip-direction vectors and the amount of spread 

were determined for cross-strata dips in each of the three 

upper formations of the Supai Group (chapter K). Results 

of this statistical study, as illustrated in figures K7, K15, 

K16, K21, and K22, show that the general current dipdirection in the Manakacha was southerly across the entire 

Grand Canyon area. In the Wescogame it was southeasterly in the west, but ranged between south and southsoutheast in the rest of the area. In the Esplanade it was 

consistently southeasterly in nearly all of the area.

The significance of these directional patterns is not easy 

to determine. The implication for all three formations is a 

source of sediment to the north with a positive area in that 

direction (figs. D4, D7, D8). In the Manakacha, however, 

where most of the cross-stratified sands are believed to be 

marine, for reasons including (1) the types of structure, 

(2) the associated fauna, and (3) the lateral gradation into 

limestone, a tidal-controlled reversal as in an estuary 

might be represented. Dip-direction measurements of 

cross-strata at Hermit Trail, Whitmore Wash, and Hidden 

Canyon show some reversals (fig. K7). The Grand Canyon 

embayment at that time (Atokan age) appears on an 

isopach map to have been a passageway that connected the 

Cordilleran seaway on the southwest with the San Juan 

Basin to the northeast, and with restricting land on each 

side (fig. D4).

In the Wescogame Formation and Esplanade Sandstone, 

the patterns of paleocurrents apparently are easier to interpret than those of the Manakacha. Cross-stratified sand of 

the Wescogame seems to be stream-deposited, as indicated 

by the common trough structures and by other features to 

be discussed. A landmass (fig. D7) lay to the north, in 

northwestern Arizona, during Virgilian time and seems to 

have furnished the southward-moving sand bodies of this 

formation. Probably the Esplanade also was fluvial, 

although this is more difficult to document. A source, 

similar to that of the Wescogame but more distant and 

more obscure, probably was operative for the Esplanade 

Sandstone.
ENVIRONMENT OF DEPOSITION 257

Determinations of the amount of spread in the current 

vectors for the principal localities of Supai study have been 

made (figs. K7, K15, K16, K21, K22). For the Manakacha, 

the maximum spread determined for a single locality was 

209°, the minimum 151°. For most localities, the spread 

was about 160°. Similar measurements for the Wescogame 

show a maximum of 240°, a minimum of 90°, and an 

average of about 170°. The Esplanade measurements 

showed a maximum of 210°, and a minimum of 60°. The 

average was approximately 150°. No significant trends can 

be recognized in a comparison of the spread of dip directions within these three sandstone bodies.

In a study of dip-azimuth variability (comparing tabular 

and trough cross-strata), Meckel (1967, p. 85, table 1) 

determined foresets of tabular cross-strata to have a scatter 

of 150°, and a comparable group of trough foresets, a scatter of 330°. Trough axes, however, showed only a 

93°-spread. In the Supai study, one might expect the Manakacha, with no trough structures, and the Wescogame, 

with many, to show differences in spread comparable to 

those determined by Meckel, but such were not found.

Distribution pattern of 

size grades in sand

More than 800 grain-size determinations (figs. K4, KlO, 

K19) for sandstones of the Supai Group indicate a remarkable uniformity across the entire Grand Canyon area and 

for all ages from Early Pennsylvanian through Early Permian. In all four formations, a large majority of samples 

show most mean values to be in the very fine grained class 

(Wentworth scale). In the Watahomigi, comparatively little sand is coarser than very fine grained, and quartz grains 

are mostly of silt size. In the three upper formations, finegrained sand is relatively abundant, but very little sand is 

coarser. Sparse accumulations of grains in the coarse and 

very coarse classes are scattered through localities of both 

eastern and western, but not central, Grand Canyon in the 

Manakacha and Wescogame Formations (figs. K3, K9), 

and are interpreted as evidence of two source 

areas—northwest and northeast. Similar uncommon concentrations of coarse and very coarse sand occur in the 

Esplanade Sandstone (fig. K18), but are distributed mostly 

through west-central Grand Canyon, suggesting a single 

main source of sand to the north in Permian time.

General scarcity of 

normal ripple marks

The general scarcity, rather than the overall distribution, of ripple marks in the extensive, cross-stratified sandstones of the Supai Group, is characteristic. Considering

the evidence of high-energy conditions furnished by the 

presence of medium- to large-scale cross-strata almost 

everywhere throughout the sandstone bodies, this paucity 

of ripple marks seems sufficiently distinctive to be a 

diagnostic feature of the facies.

Although ripple marks occur in shaly siltstones and 

mudstones of all formations, as described in chapter N, 

these strata represent relatively low-energy environments. 

In the highly cross-stratified sands formed by trains of 

megaripples or sand waves, the only small-scale ripple 

marks to be recorded were in the Manakacha (three sites), 

Wescogame (five sites), and Esplanade (three sites).

This small distribution of ripple marks suggests that in 

the sandstone environment, ripples were developed on the 

surfaces of subaqueous dunes or megaripples only rarely, 

as during waning stages, when the current energy had been 

reduced greatly from that responsible for the crossstratification itself. This, of course, is in direct contrast to 

the environment of a river floodplain or overbank deposit 

(Collinson, 1970, p. 42), or a tidal-flat surface such as that 

at Cholla Bay, Mexico (McKee, 1957, p. 1735), in all of 

which facies ripple marks are abundant.

Gradation from calcareous 

sandstone to arenaceous limestone

The distribution of lithologic facies in the Supai Group, 

perhaps better than any other single feature, serves to indicate the general pattern of environments. Medium- to 

large-scale cross-stratified sandstones and limestones give 

evidence of high-energy conditions, and the limestones, 

dolostones, and mudstones indicate various degrees of 

low-energy environments (Lumsden, 1974, p. 453). Also 

pertinent are the lateral relations between cross-stratified 

limestones and cross-stratified sandstones for they serve to 

locate areas of mingling between definite marine deposits 

and deposits of questionable origin—nearshore, barrierbar, estuarine, or fluvial environments.

The carbonate rock facies in the Supai are described in 

chapter P, and diagnostic features of the mudstones are 

treated in chapter I. It now remains to discuss for each formation the distribution of facies within the high-energy, 

cross-stratified deposits where sand and carbonate 

sediments mingle.

In the Watahomigi Formation, all or nearly all deposits 

of the Grand Canyon area indicate a low-energy environment (fig. P6). This is expectable in view of the paleogeography—nearly enclosed embayment with entrance only 

from the west (fig. D3). The upper and lower units of this 

formation are composed of alternations of mudstone or 

siltstone and limestone, and the middle unit is mostly 

limestone.
258 THE SUPAI GROUP OF GRAND CANYON

A few thin sets of cross-stratified sandstone (at Twentynine Mile Canyon, Kaibab Trail, north), and cross-stratified limestone (at Twin Springs and at north Hidden Canyon) occur in the upper unit of the Watahomigi as shown 

in stratigraphic profiles (figs. A2-A8). These sets constitute 

the only evidence of high-energy deposition. Limestones in 

the eastern half of the region are aphanitic types (micrite), 

probably indicative of very low-energy conditions. Only 

in the west do dominantly bioclastic, peloidal, and accretal 

limestones, indicating moderate energy, occur.

In the Manakacha Formation, in contrast to the Watahomigi, extensive, thick sandstone and limestone units 

characterized by medium- to large-scale cross-strata constitute much of the formation. Analysis of the measured 

sections shows that in western and west-central Grand 

Canyon, limestone constitutes a major part of the formation, the lower part and the topmost part being very arenaceous and cross-stratified, whereas much of the middle 

part is massive and jasper-bearing. In addition to the 

limestone, some thick beds of calcareous sandstone, which 

are largely cross-stratified, make up the section.

This sequence of strata extends eastward to about Toroweap Valley, beyond which the preponderance of arenaceous limestone over calcareous sandstone is reversed and 

an appreciable increase in siltstone is evident. In easternmost Grand Canyon, cross-stratified sandstone is the 

dominant element, but limestones of the massive, jasperbearing type are also present. Thus, an interpretation for 

the Manakacha of a largely marine environment, with a 

large proportion of high-energy deposits, is supported by 

data on facies change from carbonate rock (seaward), 

through arenaceous limestone, to siltstone (landward). 

Furthermore, paleogeography of Atokan time gives 

evidence that a channel connection extended northeastward to the San Juan Basin (fig. D4). The extensive 

sandstone body of the Manakacha, including some exceptionally large-scale foresets (60-100 ft long), may possibly 

represent an estuary (d'Anglejan, 1971), or a tidal sand 

body as in the Bay of Fundy (Swift and McMullen, 1968), 

or Lower Cook Inlet (Bouma and others, 1977). Table Ll 

lends support to this interpretation.

The Wescogame Formation consists almost entirely of 

medium- to large-scale, cross-stratified sandstone 

throughout most of the Grand Canyon area. Only in the 

extreme western part (Iceberg Canyon) and northwestern 

area (Snap Canyon, Hidden Canyon, and others) is this 

sandstone supplanted or partly supplanted by crossstratified limestone. Therefore, aside from relatively minor 

units of mudstone and siltstone largely in the basal and 

topmost parts, this formation represents the high-energy 

deposits of megaripples and sand waves throughout. Probably the entire central and eastern parts, excluding a few 

tongues of cross-stratified limestone at Whitmore Wash,

Toroweap Valley, and elsewhere, were formed in a continental environment. Based on other evidence already 

discussed, a braided-stream environment is postulated.

The main cliff unit of the Esplanade Sandstone is highly 

cross-stratified on a medium to large scale nearly everywhere in the Grand Canyon area. An exception is in the extreme west where its stratigraphic position is taken by the 

Pakoon Limestone (McNair, 1951)—a carbonate rock, 

mostly dolostone. A few thin tongues of carbonate rock 

extend eastward into central Grand Canyon from the 

Pakoon (fig. P12), and partings or thin lenses of mudstone 

and siltstone occur between major sandstone units 

throughout the area. Otherwise the high-energy, partly 

upper-flow regime, strata and cross-strata make up the entire cliff unit.

The relatively abrupt change from fine-grained dolostone in the west, which presumably represents nearshore, 

shallow water, and low-energy deposits, and the highenergy environment sandstones to the east is difficult to explain. As discussed earlier, several types of evidence seem 

to indicate a fluvial origin for the sandstone, so it may 

have formed as a southward-advancing sand sheet from 

braided streams, with sand sources to the north or northwest. A barrier-bar environment must also be considered 

as a possibility, especially in the northwest where 

evaporite deposits are associated.

Associated organismsplants and animals

In determining the genesis of various sand bodies in the 

Supai Group on the basis of associated fossils, a considerable amount of discretion must be used. In the first place, 

extremely few fossils occur actually within the sand, but 

rather they occur in limestones and mudstones above or 

below, so they may represent very different environments 

of deposition that resulted from transgressions and regressions. In the second place, even those fossils that occur 

within the cross-bedded sands may have been transported 

great distances from places of origin for they are nearly all 

comminuted and abraded and are in sediments that represent high-energy conditions.

Despite all the inherent difficulties in using faunal and 

floral features for interpreting the sandstone facies, a 

survey of evidence is desirable. For the Watahomigi Formation, because it contains very little sandstone, conclusions are relatively simple. Marine invertebrate fossils 

extend eastward in limestone and mudstone beds of the 

formation at least to the central part of the Grand Canyon 

region, as described in chapter E (figs. E1-E6). Five species 

of brachiopods have been recorded from Toroweap 

Valley, also one from Tuckup, five from National, and
ENVIRONMENT OF DEPOSITION 259

two from Havasu Canyons, farther east. Gastropods, pelecypods, trilobites, corals, and bryozoans are also represented in the central and western parts of the embayment 

indicating that much of the deposition there was under 

low-energy, marine, or brackish-water conditions, and explaining why medium- and large-scale, cross-stratified 

sands that form under high-energy conditions are absent in 

this formation.

Microfossils provide additional environmental evidence 

for the Watahomigi. In the upper unit of the formation 

(Atokan age), fusulinids have been found at Grandview 

Trail, Eminence Fault, and Kaibab Trail, north, in eastern 

Grand Canyon. Furthermore, bioclasts consisting of pelmatozoans, foraminifers, and bivalves, even though not as 

abundant as in the west, are represented at a number of 

localities in the far eastern sections (figs. E25-E28) and help 

to confirm the general concept of a marine environment.

The Manakacha Formation apparently represents a continuation in time of marine conditions found in the Watahomigi, although its abundant highly cross-stratified sandstones and limestones testify to a much higher energy 

situation. Apparently the very mobile and constantly shifting sand of the extensive sand bodies in this formation constituted an environment unfavorable to most forms of life. 

Fusulinids are found near the formation base in sections at 

Hermit and Grandview Trails and at Eminence Fault and in 

the middle part of the formation at Parashant and Twin 

Springs Canyons (fig. Ell), but nowhere are they as abundant as in localities farther west. Endothyra occur in the 

upper part of the Manakacha in sections at Bass Trail, 

Whitmore Wash, and Twin Springs Canyon (fig. E12). 

Larger animals (macrofossils) are represented in these 

sandstone strata only as bioclasts, and these fragments are 

progressively less numerous toward the east. A few clasts 

of pelmatozoans, bryozoans, and bivalves are found at 

scattered localities in eastern and central Grand Canyon 

(figs. E29, E30). Thus, the faunal distribution within the 

Manakacha seems to show a progressive change from 

more marine deposits in the west to more nonmarine in the 

east.

In the Wescogame Formation, a marine fauna in its life 

habitat, with unbroken shells and skeletons preserved, 

seems to be restricted to the extreme western margins of 

the region of deposition. It occurs at Hidden Canyon, 

Pigeon Wash, Snap Canyon, and Guano Cave sections. 

The principal forms at these localities are pelecypods, 

corals, and fusulinids (fig. E13). Eastward from this area, 

only the clasts of marine fossils, uncommon and scattered, 

have been found and they are far more numerous in the 

west than in the east (fig. E31). Pelmatozoan clasts were 

noted at Bunker Trail and Kaibab Trail, north, in the east 

and at many places in central Grand Canyon. Bryozoan 

clasts were found only at Thunder River Trail in the east, 

and clasts of bivalves at Grandview Trail, and Kaibab

Trail, south, and Havasu and S B Canyons.

In no part of the Wescogame in the Grand Canyon 

region can fossils be considered abundant, but they are 

especially uncommon in the highly cross-stratified sandstone facies that composes a major part of the formation. 

The principal animal forms recorded in the sandstones are 

fusulinids, small foraminifers, and sharks teeth, all of 

which may have been transported far from their life 

habitats. Mollusks, which apparently favored a quietwater environment and are found in some parts of the formation, are not known from either the sandy crossstratified limestones or the calcareous sandstones. Thus, 

the conclusion seems inescapable that a very impoverished 

fauna is represented by fossils of the Wescogame—likely 

the result of vigorous estuarine conditions across much of 

the region.

In contrast to the marine fauna of the Wescogame in the 

far western parts of the region and the scattered clasts and 

tests of marine animals farther east, possibly transported 

long distances, are the tracks or footprints of terrestrial 

quadrupeds that are present on the foresets of crossstratified sandstones, mostly in eastern Grand Canyon. 

These vertebrate tracks, probably formed by amphibians 

(figs. E22, E21), have been found near the Bright Angel, 

Hermit, and Kaibab (north and south) Trails in the east 

and at S B, Parashant, and Andrus Canyons in the center 

and west. They probably indicate a stream-bank environment, which is compatible with the estuarine conditions at 

the mouths of braided streams, suggested by the marine 

bioclasts.

In the Esplanade Sandstone, fossil evidence of the depositional environment is much like that for the underlying 

Wescogame. Complete specimens of marine animals such 

as brachiopods, corals, bryozoans, and gastropods have 

been found only in carbonate rocks (referred to the 

Pakoon) of far western sections, along the Grand Wash 

Cliffs (fig. E17). Such fossils are locally abundant in those 

facies, as also are fusulinids; however, some fusulinids are 

recorded from as far east as Whitmore Wash and S B, Blue 

Mountain, and Twin Springs Canyons (figs. E18, E19).

Bioclasts, formed mostly of pelmatozoan and bivalve 

fragments and of small foraminifers (fig. E32), are relatively widespread in the formation throughout the region, occurring as far east as 16.5 Mile Canyon, Hermit Trail, and 

Thunder River Trail, and being represented in many sections of central Grand Canyon. Some of the bioclastic 

debris may have been locally derived as suggested by its 

broad distribution, discussed in chapter E. The alternative 

explanation, that it was entirely the result of eastward 

transportation, is supported by the evidence of a highenergy environment indicated by cross-stratified sandstone 

and by independent evidence of a transitional marine 

environment.
260 THE SUPAI GROUP OF GRAND CANYON

Associated evaporites

The Esplanade Sandstone is the only formation in the 

Supai Group, so far as is known, that includes evaporite 

deposits. As described in chapter S, such deposits are 

known to occur as facies within strata of Early Permian 

age in four areas of northern Arizona and adjacent states. 

The largest of these deposits is composed of the saltgypsum beds of the Holbrook basin, southeast of the 

Grand Canyon area. The other three consist of small 

deposits or series of deposits of bedded gypsum (1) in 

northeastern Arizona and adjoining Utah, (2) in the northwestern part of the Grand Canyon area, and (3) west of 

Grand Canyon in southern Nevada.

The importance of the evaporite deposits in western 

Grand Canyon to the interpretation of the Esplanade sand 

bodies probably is considerable; however, many details of 

their relationship are not known because of a lack of exposures in critical areas. The implication of an arid or 

semiarid climate in which gypsum was precipitated from 

concentrated waters seems inescapable. Less clear, however, is the exact relationship of the adjacent cross-stratified sands to the evaporites on the north. Whether these 

sands were part of a shallow, marine barrier-bar system 

that was responsible for lagoon development or, as seems 

likely from evidence already cited, were the product of 

braided river or estuarine development, cannot be determined without more data.

Dolostone and limestone of the Pakoon to the southwest 

of the gypsum beds probably are at a slightly lower stratigraphic horizon (fig. C8). The high-energy cross-stratified 

sandstone below, and therefore older than the gypsum, is a 

time-equivalent of the Pakoon carbonate rocks. Thus, the 

lateral relations of the evaporites to the nearest definite 

marine deposits are not yet known for this area.

CONCLUSIONS REGARDING 

SANDSTONE FACIES

The Watahomigi Formation

In the Watahomigi Formation, a low-energy, marine environment of deposition is postulated for the small sandstone bodies. Evidence bearing on this environmental interpretation is summarized below.

A nearly complete absence of medium- or large-scale 

cross-strata of either planar or trough type indicates that 

high-energy conditions did not prevail. No horizontally 

laminated beds of the type characteristic of upper flow 

regime have been recorded. Low-angle strata that are distinctive of foreshore beaches have not been observed.

Small-scale cross-strata, especially ripple laminae and

climbing ripples, relatively numerous in detrital sediments 

of the upper and lower units, are interpreted as the result 

of low-energy conditions. Further evidence is furnished by 

the grain-size distribution of quartz particles. A large majority are of silt size and nearly all the others are very fine 

sand—considerably finer than in the three overlying "high 

energy" formations of the Supai.

Principal evidence that the depositional environment of 

the Watahomigi was marine is found in the close association of the sandstone beds with limestone that extends 

across the entire region. Furthermore, some of this limestone contains brachiopods, corals, bryozoans, trilobites, 

and other normal sea types, eastward as far as Havasu 

Canyon in central Grand Canyon. Small foraminifers and 

bioclasts of several animal groups are fairly numerous in 

most localities, even in the easternmost parts of the embayment, and are considered further evidence of a marine environment throughout the area.

The Manakacha Formation

In the Manakacha Formation, the principal sand bodies 

are moderately thick and very widespread, with sheetlike 

proportions, and are interpreted as having formed in a 

high-energy marine or estuarine environment. Principal 

evidence of this high-energy environment is furnished by 

the large proportion of sandstone beds that show either the 

tabular-planar structure of sand waves or the horizontal 

laminae of an upper flow regime. Evidence of low-energy 

levels is generally lacking because small-scale cross-strata 

and ordinary ripple marks—both characteristic of lowenergy conditions in the sandstones—are rare.

Principal evidence of marine genesis of the Manakacha 

is the large amount of cross-stratified limestone that extends eastward across the entire area of Grand Canyon, 

apparently grading into sandstone with similar cross-strata 

in many places. Foreset planes of these structures are 

exceptionally long, ranging from 50 to 100 ft or more in 

numerous localities, especially in central Grand Canyon. 

Such long foresets can best be explained as the fronts of 

very large sand sheets, formed perhaps in strong tidally affected areas (table Ll) or as the foresets of small deltas built 

into standing bodies of water. The absence of trough-type 

structures throughout the sandstone bodies seems to indicate that megaripples (subaqueous dunes) were not important in sedimentation and that neither braided-stream 

nor meander-belt rivers were involved.

Organisms preserved in the sand bodies indicate a very 

unfavorable environment for life. A few fusulinids have 

been found scattered throughout the region and bioclasts 

derived chiefly from bivalves, bryozoans, and pelmatozoans are accumulated locally, but may have been transported from a distance.
ENVIRONMENT OF DEPOSITION 261

The Wescogame Formation

Sandstones of the Wescogame Formation are interpreted 

as having formed primarily in a high-energy, fluvial 

environment. Within the Grand Canyon region, most of 

this formation consists of a cross-stratified facies that includes both tabular and trough structures that clearly indicate high-energy conditions. The high proportion of 

large trough cross-strata in association with tabular crosssets and horizontal bedding suggests development from 

megaripples, probably as migrating point bars in a fluvial 

system. The common association of horizontal strata indicates frequent change from lower to upper flow regime.

Current vectors determined from cross-strata dip directions indicate a unidirectional, south or southeasterly 

movement with a spread of less than two quadrants at all 

localities. Sand-size studies show a distribution pattern of 

grain size in which coarse and very coarse grains are concentrated in western and eastern, but not in central, localities. This is interpreted as indicating sources for the sand to 

the northwest and northeast.

Faunal evidence seems to indicate a cyclical mixture of 

environments. The preservation of five-toed quadruped 

tracks on the dip slopes of large-scale cross-strata at 

numerous localities in the east and north (chapter E) is 

believed to indicate stream-bank environments at those 

places. Fusulinids, small foraminifers, and sharks teeth in 

central and western Grand Canyon suggest a possible estuarine environment at the river mouths where tidal exchange could have caused vigorous upstream movement, 

transporting these fossils. In any event, the fauna was an 

impoverished one, for well-preserved marine fossils occur 

only in the extreme western or seaward margin of the area 

at Grand Wash Cliffs.

The Esplanade Sandstone

Although most of the Esplanade Sandstone clearly is a 

high-energy deposit, the problem of whether the large- to 

medium-scale cross-strata within it are marine or continental is difficult to determine. Available data seem to indicate 

that deposition of this sandstone took place along a strandline, so evidence of both marine and nonmarine sediments 

is represented. The sandstone is referred to a fluvial(?) 

genesis in this publication, but several features included in 

the sandstone seem to point toward a marine or estuarine 

environment.

The cross-stratification, which is dominantly of the 

planar type, might be attributed equally well to each of 

several marine and continental environments. Very large 

scale foresets such as occur in the Manakacha are not 

known, and trough-type structures, which are abundant in 

the Wescogame, are relatively uncommon in the Esplanade. Thus, these structural features, which are considered

useful indicators of marine and fluvial conditions, respectively, cannot be used for interpretation.

Horizontal stratification, locally in juxtaposition with 

large-scale cross-strata, is considered evidence of occasional 

high-flow regime in the Esplanade. In contrast, a general 

scarcity of small-scale structures such as climbing ripples 

and flaser bedding and of normal ripple marks in the sandstone negates the likelihood of a low-energy environment.

The association of bedded gypsum with the sandstone 

(chapter S) in the north-central and northwestern parts of 

the Grand Canyon region suggests that there a series of 

lagoons was cut off from the sea by sands. A few fusulinids 

in the central part of the region and bioclasts widespread in 

areas of cross-bedded sand seem to indicate marine encroachment, perhaps estuarine, into this central part. Carbonate rock (Pakoon) and complete skeletons of marine 

animals are restricted to the extreme western part of the 

region and probably mark the limits of normal sea encroachment from the west.

A distribution pattern of quartz-size grades and the vector direction of cross-strata dips both indicate a south 

to southeasterly transport direction of sand. This evidence 

indicates that sands were deposited as a product of streams 

from the north with possibly some sand being reworked 

into a barrier-bar system on the south, beyond the gypsumforming lagoons.

The presence of scattered fusulinids and bioclasts in the 

central area indicates possible upstream transport of marine 

invertebrates—perhaps by tides active in an estuarine 

system.

REFERENCES CITED

Aario, Risto, 1971, Syndepositional deformation in the Kurkiselfa Esker, 

Kiiminki, Finland: Geological Society of Finland Bulletin, v. 43, 

p. 163-172.

____1972, Associations of bed forms and paleocurrent patterns in an 

esker delta, Haapajaervi, Finland: Academia Scientiarum Fennicae, 

Annales, ser. A, III, Geologica-Geographica, Helsinki, 55 p.

Alien, J.R.L., 1963a, Asymmetrical ripple marks and the origin of waterlaid cosets of cross-strata: Liverpool and Manchester Geological 

Journal, v. 3, p. 187-236.

____1963b, The classification of cross-stratified units, with notes on 

their origin: Sedimentology, v. 2, no. 2, p. 93-114. 

_1965, Fining upwards cycles in alluvial successions: Liverpool and

Manchester Geological Journal, v. 4, pt. 2, p. 229-246.

d'Anglejan, B. F., 1971, Submarine sand dunes in the St. Lawrence Estuary: Canadian Journal of Earth Sciences, v. 8, p. 1480-1486.

Bernard, H. A., and Major, C. F., Jr., 1963, Recent meander belt deposits 

of the Brazos River—An alluvial "sand" model [abs.]: American 

Association of Petroleum Geologists Bulletin, v. 47, no. 2, p. 350.

Bernard, H. A., Major, C. J., Jr., Parrott, B. S., and LeBlanc, R. }., Sr., 

1970, Recent sediments of southeast Texas—A field guide to the 

Brazos alluvial and deltaic plains and the Galveston barrier island 

complex: Austin, Texas University Bureau of Economic Geology 

Guidebook 11, 83 p.
262 THE SUPAI GROUP OF GRAND CANYON

Bouma, A. H., Hampton, M. A., Wennekens, M. P., and Dygas, J. A., 

1977, Large dunes and other bedforms in Lower Cook Inlet, Alaska: 

Offshore technology conference, 9th Annual, Houston, Texas, Proceedings, v. 1, OTC2737, p. 79-90.

Brown, L. F., Jr., 1973, Cratonic basins; Terrigenous clastic models, in 

L. F. Brown, Jr., A. W. Cleaves, II, and A. W. Erkleben, eds., Pennsylvanian depositional systems in north-central Texas; a guide for interpreting terrigenous clastic facies in a cratonic basin: Geological 

Society of America Guidebook 14, p. 10-30.

Clifton, H. E., 1976, Wave formed sedimentary structures; a conceptual 

model, in Beach and nearshore sedimentation: Society of Economic 

Paleontologists and Mineralogists Special Publication 24, p. 126-148.

Clifton, H. E., Hunter, R. E., and Phillips, R. L., 1971, Depositional 

structures and processes in the non-barred high-energy nearshore: 

Journal of Sedimentary Petrology, v. 41, no. 3, p. 651-670.

Collinson, J. D., 1970, Bedforms of the Tana River, Norway: Geografiska 

Annaler, Series A, v. 52, no. 1. p. 31-56.

Dalrymple, R. W., Knight, R. J., and Lambiase, J. J., 1978, Bedforms and 

their hydraulic stability relationships: Nature, v. 275, no. 5676, 

p. 100-104.

Davidson-Arnott, R.G.D., and Greenwood, Brian, 1974, Bedforms and 

structures associated with bar topography in the shallow-water wave 

environment, Kouchibouguac Bay, New Brunswick, Canada: Journal of Sedimentary Petrology, v. 44, no. 3, p. 698-704.

____1976, Facies relationships on a barred coast, Kouchibouguac Bay, 

New Brunswick, Canada, in Beach and nearshore sedimentation: 

Society of Economic Paleontologists and Mineralogists Special Publication 24, p. 149-168.

Frazier, D. E., and Osanik, A., 1961, Point-bar deposits, Old River 

Locksite, Louisiana: Gulf Coast Association of Geological Societies 

Transactions, v. 11, p. 121-137.

Harms, J. C, MacKenzie, D. B., and McCubbin, D. G., 1963, Stratification in modern sands of the Red River, Louisiana: Journal of 

Geology, v. 71, no. 5, p. 566-580.

Harms, J. C., Southard, J. B., Spearing, D. R., and Walker, R. G., 1975, 

Depositional environments as interpreted from primary sedimentary 

structures and stratification sequences: Society of Economic Paleontologists and Mineralogists, lecture notes for short course no. 2, 

Dallas, Aprils, 1975, p. 103-132.

Hoyt, J. H., 1967, Occurrence of high-angle stratification in littoral and 

shallow neritic environments, central Georgia coast, U.S.A.: Sedimentology, v. 8, no. 3, p. 229-238.

Hoyt, J. H., and Henry, V. J., Jr., 1967, Influence of island migration on 

barrier-island sedimentation: Geological Society of America Bulletin, v. 78, no. 1, p. 77-86.

Lumsden, D. N., 1974, Relationships among insoluble residue, dolostone 

and limestone facies: Journal of Sedimentary Petrology, v. 44, no. 2, 

p. 450-455.

McGowen, J. H., and Garner, L. E., 1975, Physiographic features and 

stratification types of coarse-grained point bars; modern and ancient 

examples: Austin, Texas University Bureau of Economic Geology, 

Geological Circular 75-9, 25 p.

McKee, E. D., 1938, Original structures in Colorado River flood deposits 

of Grand Canyon: Journal of Sedimentary Petrology, v. 8, no. 3, 

p. 77-83.

____1939, Some types of bedding in the Colorado River delta: Journal 

of Geology, v. 47, no. 1, p. 64-81.

____1957, Primary structures in some Recent sediments: American 

Association of Petroleum Geologists Bulletin, v. 41, no. 8, 

p. 1704-1747.

____1966, Significance of climbing-ripple structure, in Geological Survey Research 1966: U.S. Geological Survey Professional Paper 

550-D, p. D94-D103.

McKee, E. D., Crosby, E. J., and Berryhill, H. L., Jr., 1967, Flood deposits, Bijou Creek, Colorado, June 1965: Journal of Sedimentary 

Petrology, v. 37, no. 3, p. 829-851.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern Arizona: American Association of Petroleum Geologists Bulletin, v. 35, 

no. 3, p. 503-541.

Meckel, L. D., 1967, Tabular and trough cross-bedding—Comparison of 

dip azimuth variability: Journal of Sedimentary Petrology, v. 37, 

no. 1, p. 80-86.

Off, Theodore, 1963, Rhythmic linear sand bodies caused by tidal currents: American Association of Petroleum Geologists Bulletin, v. 47, 

no. 2, p. 324-341.

Reineck, H. E., and Wunderlich, Friedrich, 1968, Classification and origin of flaser and lenticular bedding: Sedimentology, v. 11, p. 99-104.

Schuchert, Charles, 1918, On the Carboniferous of the Grand Canyon 

of Arizona: American Journal of Science, 4th ser., v. 45, p. 347-361.

Simons, D. B., and Richardson, E. V., 1961, Forms of bed roughness in 

alluvial channels: American Society of Civil Engineers Proceedings, 

v. 87, paper 2816, Hydraulics Division Journal, no. HY3, pt. 1, 

p. 87-105.

Simons, D. B., Richardson, E. V., and Nordin, C. F., Jr., 1965, Sedimentary structures generated by flow in alluvial channels, in G. U. 

Middleton, ed., Primary sedimentary structures and their hydrodynamic interpretation—A symposium: Society of Economic 

Paleontologists and Mineralogists Special Publication 12, p. 34-52.

Singh, I. B., 1972, On the bedding in the natural-levee and the pointbar deposits of the Gomti River, Uttar Pradesh, India: Sedimentary 

Geology, v. 7, no. 4, p. 309-317.

Smith, N. D., 1970, The braided stream depositional environmentComparison of the Platte River with some Silurian clastic rocks, 

north-central Appalachians: Geological Society of America Bulletin, 

v. 81, no. 10, p. 2993-3013.

Sundborg, Ake, 1956, The river Klaralven; a study of fluvial processes: 

Geografiska Annaler, v. 38, p. 127-316.

Swift, D.J.P., and McMullen, R. M., 1968, Preliminary studies of intertidal sand bodies in the Minas Basin, Bay of Fundy, Nova Scotia: 

Canadian Journal of Earth Sciences, v. 5, no. 2, p. 175-183.

Thompson, W. O., 1937, Original structures of beaches, bars, and dunes: 

Geological Society of America Bulletin, v. 48, no. 6, p. 723-751.

Van Straaten, L.M.J.U., 1959, Minor Structures of some recent littoral 

and neritic sediments: Geologie en Mijnbouw, v. 21, p. 197-216.

Walker, R. G., 1976, Facies models 3; sandy fluvial systems: Geoscience 

Canada, v. 3, no. 2, p. 101-109.

White, David, 1927, Study of the fossil floras in the Grand Canyon, 

Arizona: Carnegie Institution of Washington Year Book 26, 

p. 366-369.

____1928, Study of the fossil floras in the Grand Canyon, Arizona: 

Carnegie Institution of Washington Year Book 27, p. 389-390.

____1929, Flora of the Hermit Shale, Grand Canyon, Arizona: Carnegie Institution of Washington Publication 405, 221 p. 

Williams, G. E., 1968, Formation of large-scale trough cross-stratification

in a fluvial environment: Journal of Sedimentary Petrology, v. 38,

no. 1, p. 136-140. 

____1971, Flood deposits of the sand-bed ephemeral streams of central

Australia: Sedimentology, v. 17, no. 1-2, p. 1-40.
THE SUPAI GROUP OF GRAND CANYON

INSOLUBLE RESIDUE PATTERNS

Chapter M 

By WALTER PIERCE, A. J. GUDE, III, and EDWIN D. McKEE

Contents

General features ........................................

Insoluble residues of the Watahomigi Formation . .

Insoluble residues of the Manakacha Formation ...............

Insoluble residues of the Wescogame Formation ......... .

Insoluble residues of Esplanade Sandstone and Pakoon Limestone 

References cited ........................................

Page

265

265

265

272

272

272

263
264 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURES M1-M6. Histograms showing distribution by 10-percent classes of insoluble residues in 

rocks of Supai Group (Pakoon Limestone included in western Grand Canyon): 

M1. Generalized total ..... ... ............ . .............. 266

M2. From northwest to southeast in western Grand Canyon ... 267 

M3. From north to south in western Grand Canyon ....................... 268

M4. From west to east in western Grand Canyon . .................. 269

M5. From west to east in eastern Grand Canyon ....................... ..... 270

M6. From west to east in central and eastern Grand Canyon ..................... 271
INSOLUBLE RESIDUE PATTERNS 265

GENERAL FEATURES

The four formations that comprise the Supai Group 

(ascending order), the Watahomigi, Manakacha, and 

Wescogame Formations, and the Esplanade Sandstone, 

show considerable differences in the amount and distribution of insoluble residues across the region. Determinations obtained mostly as byproducts from sieve analyses of 

sandstones and from Ca-Mg analyses of carbonate rocks 

from 1,018 samples were used in a study of distribution 

patterns. Cross-checks were available for some samples 

that were determined for both mechanical and Ca-Mg 

analyses.

In this investigation, all available analyses were compiled and organized into two types of histogram. In one of 

these (fig. Ml) the insoluble residue distribution was 

generalized for each formation of the Supai to show the 

total number of analyses in each 10-percent class of residues. In the other type of histogram (figs. M2-M6) the percent of samples in each 10-percent insoluble residue class 

was plotted for 12 to 22 localities representing each of the 

formations.

Histograms of the second type were arranged with 

localities roughly along east-west and north-south lines so 

that their relative geographic positions are indicated and 

comparisons of localities across the region are facilitated. 

Because the detrital and carbonate rocks are transitional 

and grade from one area to another, the insoluble residue 

distribution serves well to indicate places of good and poor 

mixing. In western Grand Canyon, the Pakoon Limestone 

(McNair, 1951) was combined with the Esplanade Sandstone because of the intertonguing relationship between 

these two formations.

Histograms of the first type (fig. Ml) show a distinct 

bimodality in insoluble residue distribution for Watahomigi (fig. MID), Wescogame (fig. M1B), and EsplanadePakoon (fig. ML4) rocks, whereas several nearly equal 

peaks of distribution are found in the Manakacha (fig. 

MIC). In the Wescogame and Esplanade-Pakoon histograms, the detrital peak is definitely in the 60-80 percent 

insoluble residue range, but in the Watahomigi it is both 

higher and less pronounced (fig. MID), which may be a 

reflection of the low-energy depositional environment 

involved.

Rocks intermediate in their insoluble content are generally considered to be uncommon in the geologic record. 

This situation is represented by the three bimodal histograms (figs. M1A B, D) referred to above, but the 

Manakacha Formation (fig. MIC) seems to represent a 

notable exception. Possibly the good mixing of detrital 

and carbonate elements in this formation can be attributed 

to the high-energy environment of deposition, as illustrated by the abundance of cross-stratified limestones 

throughout.

Very few detrital rocks in the Supai Group are without 

carbonate cement, which accounts for some rock types in 

the 90-100 percent class of insolubles in all formations. In 

contrast, appreciable amounts of pure limestone and pure 

dolostone in all but the Manakacha Formation are represented in the 0-10 percent class of these formations.

INSOLUBLE RESIDUES 

OF THE WATAHOMIGI 

FORMATION

A composite histogram of insoluble residues for the 

Watahomigi Formation (fig. MID) shows that most sandy 

carbonate rocks of this formation are relatively pure carbonates with less than 10 percent insoluble material. A 

small insoluble residue peak at 80-90 percent exists, but a 

major part of the population is in the range from 10 to 50 

percent insoluble residue.

In a series of histograms extending generally across the 

Grand Canyon region (figs. M2-M6), a trend is apparent 

from relatively pure carbonate rocks in the west to rocks of 

highly divergent insoluble content, distributed more or less 

evenly throughout the section, in the east. Between these 

extremes the insoluble residue content seems to be transitional. This record apparently is representative of a lowenergy marine environment, with detritus being introduced mostly in the eastern area.

INSOLUBLE RESIDUES 

OF THE MANAKACHA 

FORMATION

A composite histogram for the Manakacha Formation in 

Grand Canyon (fig. MIC) seems to be atypical for populations of carbonate-sandstone transition, in general. In the 

Manakacha, several distinct peaks occur in the percent 

classes of insoluble residues indicative of a gradual transition between detrital and carbonate sediments. Furthermore, in these strata more mixtures or combinations of 

rock types are represented than in any other formation in 

the Supai Group as shown by the large number of samples 

ranging between 30 and 70 percent insoluble residues.

A trend toward more carbonate-rich rocks in the west, 

as in the Watahomigi, Wescogame, and EsplanadePakoon, is recognized, however, in the Manakacha. Carbonate rocks of the western sections contain much more 

detrital sediment as illustrated by percent insoluble 

residues (figs. M2-M6) and by interbeds of noncarbonate 

types. Sandstones in the Manakacha generally contain
266

70

65

60

55

50

45

40

CO 35 

LU 

CO 30

_l 25

< 15

U_ 10

O

5

-

-

-

-

-

-

-

CSp|8i

.....Jl .J

TfcSteS

........

tdne:<

....

jttdiPpfcOQn

' .....A...

-

-

-

-

-

-

-

-

Limestone

LU 

DO A

10 20 30 40 50 60 70 80 90 100

40

35

30

25

20

15

10

5

°c

-

-

-

-

-

_

5

~

) 1 0 2

!

0 3

Sftenal'

,=.....:

0 4

cadha

''::•: -

0 5

.....•-..

0 60 7

-

-

_

-

' ——— 3 ———

*+*

T-

«

D 80 90 1C

0 10 20 30 40 50 60 70 80 90 100

B

80

75

70

65

60

55

50

45

40

35

30

25

20

15

10 

5

°c

-f T

^ • - i

r*:

- ;

^= ;

r= .

- I

-'

-:

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D

-

-

-

-

-

-

-

-

; ~

-

; ~

"' :; " : "| ____

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! t:

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;.;.,.., i ...... ..W.,,....j;....:,,J::-....:J;. ...:-*.-. - - Ji- . : : , - ... J . -.-J

0 20 30 40 50 60 70 80 90 10

PERCENT INSOLUBLE RESIDUE

FIGURE ML—Histograms showing distribution, by percent, of insoluble residues in rocks of the Supai Group and the Pakoon Limestone (McNair, 1951).

A, Esplanade-Pakoon; 8, Wescogame; C, Manakacha; D, Watahomigi.
INSOLUBLE RESIDUE PATTERNS 267

HISTOGRAMS

CQ

D °0 50 100 

z PERCENT

INSOLUBLE RESIDUE

o 1—

19

FIGURE M2.—Histograms showing distribution of insoluble residues by 10-percent classes in Supai Croup and Pakoon Limestone (McNair, 1951) from 

northwest to southeast in western Grand Canyon. Solid circles and numbers represent measured sections (fig. A1).
268 THE SUPAI GROUP OF GRAND CANYON

HISTOGRAMS

o 1-

Esplanade-Pakoon 

Wescogame

FIGURE M3 — Histograms showing distribution of insoluble residues by 10-percent classes in Supai Group and Pakoon Limestone (McNair, 1951) from 

north to south in western Grand Canyon. Solid circles and numbers represent measured sections (fig. A1).
INSOLUBLE RESIDUE PATTERNS 269

HISTOGRAMS

FEET

1000|—

500

10

0 50 100

PERCENT 

INSOLUBLE RESIDUE

o 1—

FIGURE M4.—Histograms showing distribution of insoluble residues by 10-percent classes in Supai Croup and Pakoon Limestone (McNair, 1951) from 

west to east in western Grand Canyon. Solid circles and numbers represent measured sections (fig. A1).
270 THE SUPAI GROUP OF GRAND CANYON

FEET 

1000,—

500

10

HISTOGRAMS

0 50 100

PERCENT 

INSOLUBLE RESIDUE

FIGURE M5.—Histograms showing distribution of insoluble residues by 10-percent classes in Supai Group and Pakoon Limestone (McNair, 1951) from 

west to east in eastern Grand Canyon. Solid circles and numbers represent measured sections (fig. A1).
INSOLUBLE RESIDUE PATTERNS 271

HISTOGRAMS

FEET 

10001—

500

o 1—

10

0 50 100

PERCENT 

NSOLUBLE RESIDUE

14 10

FIGURE M6.—Histograms showing distribution of insoluble residues by 10-percent classes in Supai Croup and Pakoon Limestone (McNair, 1951) from 

west to east in central and eastern Grand Canyon. Solid circles and numbers represent measured sections (fig. A1).
272 THE SUPAI GROUP OF GRAND CANYON

more carbonate material than do those of the overlying 

formations, as indicated by the relatively small number of 

analyses in the higher insoluble percentage classes (fig. 

MIC).

Two localities—Snap Canyon and Prospect Valley— 

stand out as having especially large numbers of samples in 

the intermediate range between sandstone and carbonate 

rock.

INSOLUBLE RESIDUES 

OF THE WESCOGAME 

FORMATION

The histogram for total insoluble residue analyses of the 

Wescogame Formation (fig. MlB) is similar to those of the 

Watahomigi and Esplanade-Pakoon in that it shows two 

detrital peaks, but it is smaller because it is based on fewer 

samples. Apparent on the histogram is the maximum concentration of insoluble residue samples at the 60 to 80 percent range.

The general trend in insoluble residue (sand) modes from 

west to east (figs. M2-M6) shows an eastward increase in 

size. The rate of change is by no means constant, however, 

and in two places, reversals are recorded. Most obvious is 

the change from Hidden Canyon (sec. 30) to Iceberg Canyon (sec. 31), although this is in a southwesterly, rather 

than a westerly, direction. The actual variation in modes 

across the region is summarized as follows:

Class, in percent Measured section localities (name and no.), 

insoluble residue from west to east (top to bottom)

70- 8 Iceberg Canyon ......................... 31

0- 10 Hidden Canyon ................ ...... 30

20- 30 Snap Canyon ............................ 27

60- 70 Andrus Canyon ......................... 24

40- 50 Prospect Valley ........................... 20

80- 90 National Canyon .................. 15

70- 80 Hermit Trail ............................. 9

70- 80 Kaibab Trail, south ...................... 7

90-100 Bunker Trail ....... ............ 5

INSOLUBLE RESIDUES OF 

ESPLANADE SANDSTONE 

AND PAKOON LIMESTONE

The generalized histogram for insoluble residues of the 

Esplanade Sandstone and Pakoon Limestone, undivided 

(fig. ML4), gives expectable results. Two peaks are apparent: the larger one in the insoluble residue classes between 60 and 80 percent, caused by the relatively pure 

sandstone that dominates the Esplanade in most of central 

and eastern Grand Canyon; the lesser one in the class of 

0-20 percent insolubles reflecting the relatively pure carbonate rocks of the Pakoon in the extreme western edge of 

the Grand Canyon region.

Histograms from west to east (figs. M2-M6) illustrating 

Esplanade-Pakoon insoluble residue analyses show clearly 

the effects of an abrupt facies change. As stated by Winchell (1924), this feature probably can be explained as the 

result of retarding the activities of calcium carbonatesecreting organisms by a flooding of the area with noncarbonate detritus.

REFERENCES CITED

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern Arizona: American Association of Petroleum Geologists Bulletin, v. 35, 

no. 3, p. 503-541.

Winchell, A. N., 1924, Petrographic studies of limestone alterations at 

Bingham [Utah] (with discussion): American Institute of Mining and 

Metallurgical Engineers Transactions, v. 70, p. 884-903.
THE SUPAI GROUP OF GRAND CANYON

MINOR SEDIMENTARY FEATURES,

CONTORTED STRUCTURES, AND

HOMOGENEOUS SEDIMENTARY ROCKS

Chapter N 

By EDWIN D. McKEE

Contents

Ripple marks ...........

Shrinkage cracks ........

Rain pits or craters .......

Contorted stratification . . . 

Homogeneous sandstones 

References cited ........

Page

275

276

277

277

280

285

273
274 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURES N1-N4. Photographs showing minor sedimentary structures in:

N1. Watahomigi Formation ............................................ 276

N2. Wescogame Formation ............................................ 277

N3. Wescogame Formation - ..................... ................ 278

N4. Esplanade Sandstone .............................................. 279

N5. Sketches of crinkled beds near base of Manakacha Formation .................. 281

N6. Photographs of contorted stratification in sandstones of Supai Group ............ 282

N7. Sketches of downwarps in massive sandy limestone .......................... 283

N8. Sketches of compressional structures in foreset beds ......................... 284

N9. X-ray radiographs of homogeneous sandstone, Esplanade Sandstone ............. 285
MINOR SEDIMENTARY FEATURES, CONTORTED STRUCTURES, HOMOGENEOUS SEDIMENTARY ROCKS 275

RIPPLE MARKS

Ripple marks have been found in all of the four formations of the Supai Group. They occur in numerous stratigraphic sections from Marble Canyon on the east to Iceberg 

Canyon on the west. Ripple marks are on the foreset surfaces of cross-stratified sandstones, on shaly siltstones and 

mudstones, and on silty or sandy limestones and 

dolostones.

Despite the broad range in distribution, both vertically 

and horizontally, only in a few places can ripple marks be 

considered common; in overall distribution they are very 

uncommon. Ripple marks are considerably less common in 

the Supai Group than in the overlying Permian Hermit 

Shale and very much less common than in the Triassic 

Moenkopi Formation of the same region. Their relative 

scarcity, rather than their presence or their diversity of 

form, probably is the most significant feature of this structure with regard to the Supai Group.

A considerable variation in depositional environments is 

represented by ripple marks of the Supai Group. Some are 

formed in flatbedded siltstones and mudstones that accumulated under continental conditions as indicated by associated mud cracks, rain pits, leaves of land plants, and 

other diagnostic features. Other ripple marks were formed 

under shallow marine waters as deduced from their occurrence in sandy or silty carbonate rocks interlayered with 

fossil-bearing marine limestones. Still other ripple marks 

are on the dipping foreset planes of sandstone cross-strata, 

the genesis of which may be difficult to determine.

Ripple marks of the Supai Group are of three principal 

types: (1) the parallel straight (figs. N3A, N4B) and the 

parallel sinuous or caternary (fig. N3D); (2) the tonguelike 

form that extends down-current (fig. N3B), named 

linguoid by Bucher (1919, p. 164); (3) the crescent form 

that faces down-current (fig. N3C), which is the lunate 

form of Alien (1968, p. 60). Of 21 sets of ripple marks examined and measured during the present study (see measured stratigraphic sections), 10 sets consisted of parallelstraight or parallel-sinuous and the other 11 sets were of 

crescentic (lunate or linguoid) forms.

In measuring various sets of ripple marks, the dimension 

descriptions of Alien (1963) were followed. In parallelstraight or parallel-sinuous ripples of the Supai Group, the 

height (H) ranged from 0.3 to 0.8 cm, and the wave length 

(L) from 4.2 to 9.1 cm. In crescentic forms, the range was 

from 0.6 to 1.3 cm in height and from 6.4 to 8.5 cm in 

wave length. The width range (B) was between 11.5 and 

33.2 cm.

Ripple structures in the Watahomigi Formation consist 

mainly of ripple laminae (figs. NL4, B, C; K2), in the form 

of small-scale cross-strata. These structures locally are

numerous as in the lower slope unit of the Watahomigi in 

the central part of Grand Canyon, at Havasu and National 

Canyons. Linguoid ripples occur in siltstones of the upper 

slope unit at Guano Cave (sec. 26).

In the Manakacha Formation, parallel-straight ripple 

marks occur in very fine grained sandstone units at three 

localities (National Canyon, Thunder River Trail, and 

Bass Trail) in central Grand Canyon and in shaly siltstone 

at Separation Canyon in the west. The first two of these 

ripple localities are in the upper or slope unit, in deposits 

that probably are continental. The Separation Canyon 

site is near the base of the main cliff, associated with 

shrinkage cracks, and likely also represents a continental 

environment.

Considerably more ripple marks were observed in the 

Wescogame Formation than in any other formation of the 

Supai Group. More than half of the ripple-bearing surfaces 

examined were in the main cliff unit in localities between 

Bass Trail and Andrus Canyon. All were in sandstones or 

very sandy limestones and included parallel-type ripples 

(fig. N3i4), linguoid ripples (fig. N3B), parallel-sinous ripples (fig. N3D), and climbing ripple laminae (fig. N2A). 

The climbing ripple laminae indicate deposition with an 

abundance of clastic particles available, possibly the result 

of very rapid accumulation on a flood plain, point bar, or 

similar fluvial environment (McKee, 1965, 1966).

The overlying slope unit of the Wescogame Formation, 

which includes much shaly siltstone, mudstone, and some 

very fine grained sandstone, locally contains ripple marks, 

mostly of the parallel-straight type, but some of crescentic 

forms. The localities represented are mostly in central 

Grand Canyon, but some ripple structures were at Iceberg 

Canyon in the extreme western part of the area. At that 

locality, ripple lamination is recorded near the top of the 

unit among sediments considered, on the basis of other 

structures, to be continental in origin.

The Esplanade Sandstone, which includes the largest 

sandstone body in the Supai Group, contains ripple marks 

at a number of widespread localities. Most of the ripple 

marks, however, are not in the massive sandstone of the 

main cliff unit, but are in shaly siltstone and mudstone 

near the formation base. Both on Kaibab Trail, north, in 

the east and in Iceberg Canyon to the west, tongue-shaped 

(linguoid) ripples are recorded in association with beds 

containing shrinkage cracks, leaves and stems of land 

plants, and other indicators of a continental environment. 

In a few places, ripple marks occur on surfaces of the massive sandstone of the main cliff unit as, for example, near 

Topocoba Trail where long parallel-straight type ripples 

cover large bedding surfaces (fig. N4B) and near Thunder 

River Trail where they cover foresets that have a 12° dip. 

At S B Canyon crescent-shaped ripple marks occur in very 

fine grained sandstone.
THE SUPAI GROUP OF GRAND CANYON

•*- >.. - -.-y^d wrv'-iS:':

FIGURE N1.—Minor sedimentary structures in Watahomigi Formation, 

Grand Canyon, Ariz. A, Ripple laminae in siltstone near base of formation at Navajo Falls, Havasu Canyon; 6, C, ripple lamination in silty 

limestone at 50 ft above formation base, National Canyon; D, molds of 

shrinkage cracks in red-brown mudstone, basal slope of Watahomigi 

Formation, Picacho Butte, south side.

SHRINKAGE CRACKS

Shrinkage cracks, normally of polygonal form, occur in 

the Supai Group, mostly in thin mudstone and siltstone 

beds (fig. NlD). They constitute one of the best criteria for 

the recognition of continental strata for they are characteristically developed in muddy subaerial environments such 

as estuaries, lagoons, river flood plains, or playas. Mostly 

they are formed through desiccation by the sun. Shrinkage 

cracks in the Supai commonly are associated with raindrop 

pits and various types of land plants.

The distribution of shrinkage cracks in the Supai Group 

is extensive, both from a geographic and a stratigraphic 

standpoint, yet they are not abundant in any one locality. 

Descriptions of measured sections show the presence of 

shrinkage cracks from Blue Spring and Kaibab Trail, north, 

in the east to Pigeon Wash and Snap Canyon in the west. 

They are reported from near the base of the Watahomigi 

(Schuchert, 1918, p. 357) and from the three overlying formations as described in the present publication.

The most laterally extensive single exposure of shrinkage 

cracks noted in the Supai of Grand Canyon during this 

study was in a small canyon north of Snap Point. In the 

Wescogame Formation at this locality, a mudstone layer 

2-4 in. thick, with cross-bedded calcareous sandstone 

above and below, contained shrinkage cracks for a 

distance of 70 ft, traceable along the canyon wall. The

cracks consisted of polygons 6-10 in. in diameter and 

cracks 0.5-1.0 in. wide. Similar features also occur at 

several lower horizons in the slope member of the 

Wescogame.

An analysis of the stratigraphic positions from which 

Supai shrinkage cracks have been recorded and which, 

therefore, indicate times of subaerial environment, has 

been made. It shows about one-half to be in the slope 

(mudstone) units of each formation and one-half in 

mudstone interbeds or lenses within the cliff (sandstone, 

limestone) units. An obvious conclusion from this vertical 

distribution pattern is that relative sea level was repeatedly 

rising and lowering in this area throughout PennsylvanianPermian time, causing surfaces of deposition to be above 

water level for short intervals, even during general periods 

of sedimentation.

Rounded pillow-shaped molds on the bottom of a massive sandstone bed (fig. N4A) occur in the lower slopeforming unit of the Esplanade Sandstone near the 

Topocoba Trail to Supai Village. They closely resemble 

the sand polygons described by Conybeare and Crook 

(1968, p. 42, pi. 52C) that are interpreted as "mudcrack 

moulds." The rounding of the polygons is attributed by
MINOR SEDIMENTARY FEATURES, CONTORTED STRUCTURES, HOMOGENEOUS SEDIMENTARY ROCKS 277

FIGURE N2.—Minor sedimentary structures in Wescogame Formation, Grand Canyon, Ariz. A, Climbing ripple laminae, overlain by horizontal laminae, 

in sandy limestone at top of cliff unit, Toroweap 

Point. Ripple migration from right to left. B, Contorted structure in thick-bedded sandstone showing 

folds probably caused by differential loading of sand 

in quicksand condition, cliff unit, Thunder River 

Trail. C, Shrinkage cracks in talus block from cliff 

unit, Apache Trail, Havasu Canyon.

them to weathering, but the original curved surfaces probably were concave upward as in normal polygons formed 

by cracks.

RAIN PITS OR CRATERS

An "abundance of rain prints and a few rill markings" 

were reported by Schuchert (1918, p. 357) from "thin bedded flaggy sandstones" at the base of the slope (probably 

Wescogame slope unit) below the Esplanade Sandstone 

along Hermit Trail. Since this initial report, the craters of 

raindrops have been recorded from the slope unit of the 

Manakacha Formation at Thunder River Trail and from 

the basal slope unit of the Esplanade at Kaibab Trail, 

north, and in Twin Springs Canyon.

The principal significance of these observations of rain 

pits in mudstone is that they further substantiate the occurrence of periodic times of subaerial conditions within an 

environment of dominantly subaqueous deposition. They 

are commonly associated with shrinkage cracks, plant impressions, worm burrows, and the probable algal surfaces 

known as Rivularites.

CONTORTED 

STRATIFICATION

Penecontemporaneous deformation is responsible for a 

number of distinct types of contorted stratification, each 

with an infinite variety of forms. Contortion may result
THE SUPAI GROUP OF GRAND CANYON

FIGURE N3.—Varieties of ripple marks and shrinkage cracks in Wescogame Formation, Grand Canyon, Ariz. A, Parallel-straight ripple marks 

on inclined (20°) bedding plane of foresets, Thunder River Trail. Scale in 

inches. B, Linguoid or crescent-shaped ripple marks, Apache Trail in 

Havasu Canyon. C, Lunate or cresent-shaped ripple marks and drag 

marks, Andrus Canyon. D, Parallel-sinuous ripple marks, Apache Trail in 

Havasu Canyon. Scale in inches. E, Shrinkage cracks and probable mold

»

of plant stem, near top of cliff unit, Andrus Canyon. F, Molds of 

shrinkage cracks in green siltstone; locally replaced with jasper, Hidden 

Canyon.
MINOR SEDIMENTARY FEATURES, CONTORTED STRUCTURES, HOMOGENEOUS SEDIMENTARY ROCKS 279

**>^. 1 ^^%£$^ ?j&3^z& & S^^^^/ffr ^'-^'-~"&*&*'9.. ^^^3^^- " ^ _^

' r- -' =• v- ',^^-^f^C/M • •^r*'~ - ^^

f

-r jy.- •* ^*- ^^f f^B •£ ----jt--je* 

Jjii-"-^* ^^^.^^ *> * '" ^

- - >«v», ^Z&fy $ • - v '--'*''•'•• '-•^T^-;-?"''rf. , *L~ ;- 

.^^- .. T ^' ^^'l^"^-

FIGURE N4.—Minor sedimentary structures and contorted bedding in 

Esplanade Sandstone, Grand Canyon, Ariz. A, Pillow-shaped molds 

developed on bottom of bed near base of main cliff unit, Topocoba 

Trail. 6, Parallel-straight ripple marks and casts, on sandstone blocks 

near base of main cliff unit, Topocoba Trail. C, Contorted structure in 

cross-strata of calcareous sandstone, probably resulting from differential loading. Anticline in center from escaping gas or water.

Toroweap Point. D, Small-scale contortions in thin- to mediumbedded sandstone, Kaibab Trail, north. Middle ledge with contorted 

bedding is 4 ft thick. E, Contorted structure (fold), possibly result of 

slumping at base of foresets, Bright Angel Trail. Pencil in upper right 

gives scale. F, Contorted structure, probably from loading of crossstrata sets, in limy sandstone. Toroweap Point. Pencil in center gives 

scale.
280 THE SUPAI GROUP OF GRAND CANYON

from differential loading, from avalanching in the form of 

mass slumping, from surface drag caused by sedimentladen currents, and probably from other processes 

(McKee, Reynolds, and Baker, 1962; Conybeare and 

Crook, 1968, p. 37). In the Supai Group, nearly all contorted structures seem to be attributable to either loading 

or avalanching. The numerous varieties of contorted strata 

occur widely scattered through the four formations of the 

Supai.

Differential loading with detritus at the time of, or soon 

after, deposition of a sedimentary bed normally is 

recognized by high-angle folds, as demonstrated by experiments (McKee and Goldberg, 1969). The form and size 

of the folds varies widely according to (1) the manner of 

deposition of the overlying unit, (2) the form of the 

underlying surface, (3) the direction of loading, and (4) the 

current velocity or lack of movement during loading. Anticlinal structures, resulting from differential loading, tend 

to be narrow and pointed; synclinal structures commonly 

are somewhat rounded or flat-bottomed (McKee, 1966, 

fig. 3; Aario, 1971, fig. 5). Most contorted strata of this 

type are restricted to a single set of strata or cross-strata; 

however, the thickness of layers that are affected depends 

both on the consistency of the sediment that is folded and 

on the weight of the overburden.

Near the base of the cliff unit of the Manakacha Formation, a zone of gnarly-bedded, crinkled silty limestone is 

conspicuous in numerous localities because of its distinctive structure. This zone is a prominent feature along both 

the Hualapai and the Apache Trails into Havasu Canyon 

and near Kaibab Trail, north. In these places, the zone 

containing the crinkled or crenulated beds is 1-2 ft thick; 

the beds are light-colored and form irregular, rounded anticlines and synclines spaced randomly along an extensive 

plane (fig. N5y4). The crinkled folds seem to have formed 

within layers of light-red mud, which apparently was 

squeezed while in a very fluid condition. Layers of limestone or sandstone above and below this zone are horizontal and seemingly undisturbed.

Crenulations somewhat similar to those in the Manakacha are described and illustrated by Conybeare and 

Crook (1968, pis. 29, 30, 31) in mudstones, siltstones, and 

carbonate rocks of various ages and from widely scattered 

geographical areas. They occur between undeformed beds 

and mostly are referred to as convolute bedding. Various 

interpretations are suggested for these structures, most of 

which are considered to be marine turbidites; one variety 

from the Miocene of Italy is attributed (Conybeare and 

Crook, 1968, p. 142) to "sheet slumping of unconsolidated 

sediments," possibly triggered by "weight of sediment, 

earthquake shock, or thrust turbidity currents."

Large isolated downwarps, in contrast to the folds-inseries referred to above, occur in medium to thick beds in 

sequences of otherwise horizontal strata and represent a

second variety of contortion from sediment loading. 

Downwarps of this type are found in massive beds of sandy 

limestone in the cliff unit of the Manakacha at Parashant 

Canyon (fig. N6D) and in thick-bedded sandy limestone of 

the Pakoon Limestone of McNair (1951), at Iceberg Canyon (fig. N7A). The consistency of the sediment involved 

in these folds must have been that of quicksand.

Contorted bedding, where slumping of a slipface is the 

mechanism for deforming the strata, normally involves 

two main types—that resulting from tensional stress at the 

top of a slope, and that from compression at the base. 

Eight principal types of deformational structures have been 

recognized (McKee, Douglass, and Rittenhouse, 1971). 

Most of the structures in the Supai Group that are considered typical of compression, occur in the medium- to 

large-scale cross-stratified sandstones. Compressional 

folds are numerous near the bases of avalanche planes on 

high-angle cross-strata where sand tends to pile up. Tightly 

folded strata are developed on foreset surfaces of the 

Wescogame at Thunder River Trail (fig. N6A) and along 

the Apache Trail to Supai Village (fig. N8B). An overturned fold in the Esplanade Sandstone on the Bright Angel 

Trail (fig. N8E) and rotated blocks in slump strata of 

the Manakacha at Whitmore Wash (fig. N8B) are typical.

HOMOGENEOUS 

SANDSTONES

At many places in eastern Grand Canyon, thick, massive sandstone units at various levels in the Supai Group 

seem to be structureless. These sandstones range from a 

few feet to 15 or 20 ft in thickness and show no visible textural or compositional changes either in outcrop or in hand 

specimen. Such sandstone units are seemingly homogeneous, but when traced laterally along canyon walls may be 

found to grade into sandstone in which structural features 

are clearly delineated.

Using the technique of radiography in a study of seemingly homogeneous or structureless sandstones that represent a wide variety of environments, ages, and geographic 

situations, W. K. Hamblin (1962, 1965) reached the conclusion that most such sandstones actually contain a 

definite internal structure. In more than 300 samples examined, Hamblin determined (1965, p. 3) that 97 percent 

contained grains "not packed together in random fashion, 

but arranged into distinctive structural units." Furthermore, he was able to recognize structural frameworks consisting of (1) various cross-strata types and (2) rhythmic 

laminations; also, modifications caused by "(1) burrowing 

organisms, (2) secondary mineral growth, and (3) penecontemporaneous deformation."

In the Esplanade Sandstone of eastern Grand Canyon, 

where seemingly homogenous units of sandstone are
MINOR SEDIMENTARY FEATURES, CONTORTED STRUCTURES, HOMOGENEOUS SEDIMENTARY ROCKS 281

_____ ^ "\^*^s" x"-- *^-- *•____*'—^v*'^^^-"____ -- ____

III I II II I I II I I I 

Concealed

B

EXPLANATION

Limestone

Siltstone 

Flat-bedded 

Cross-stratified

Mudstone

Sandstone 

Flat-bedded 

Cross-stratified

Conglomerate

Jasper

--— '^^>s Basal conglomerate 

__ of Esplanade

Esplanade 

Sandstone

Contorted bed—£;

Basal conglomerate —1-——... —— -— ^- 0 o <n^-v*<-i«-R—.•_jvr<=» *»_j^>cn^

of Watahomigi

FIGURE N5.—Crinkled beds near base of Manakacha Formation, Grand Canyon, Ariz. A, East of Supai Village near old fort; B, along Hualapai Trail to 

Supai Village; C, south wall of canyon near Kaibab Trail, north. Vertical and horizontal distances in feet.

numerous, samples a few inches in diameter were obtained 

from several localities for study. X-ray radiographs were 

kindly prepared by W. K. Hamblin from thin slices of 

these rocks. Structures present in the rock, but not discernable in the hand specimen were visible in the radiographs. 

Most of the samples included parts of what was believed to 

be medium- or large-scale cross-stratification (this is the

dominant structure in sandstone bodies throughout the 

Wescogame Formation and Esplanade Sandstone).

One sample of massive sandstone from the Esplanade on 

the Kaibab Trail, north, showed disrupted high-angle 

laminae and some traces of burrows or tubes (fig. N9) 

crosscutting its laminae. Probably the distortion of strata 

represents a penecontemporaneous depositional feature.
THE SUPAI GROUP OF GRAND CANYON

- ,_-•» m IBI

"£ii&i^|( >T*&&Z'±i - ''*JM

? v-; ^ T *y s f'th^'lf^yW 

' . }^ff.Jf^*'^-^f""'\ i * '\K :ffyt '"^

S r i-sv. 1 .1-.-^ sf^>.'•«,

?>/>%£? J-~ . V-' <i '2'* ^V >••' ' '' {; •' 'f4$3'-\,

• '/,^>*'***^*.^-; > • i- v- -• >

^•^^•'^-•-^f^/-- m^^-^ ; if- , - •/• JL^ & • • -T-^

*\^w>-*l jT*''C«.J-« ••" x ^ Jr

FIGURE N6.—Contorted stratification in sandstones of Supai Group, 

Grand Canyon, Ariz. A, Anticlines and synclines in Wescogame Formation from penecontemporaneous tight folding of sand body. Traces of 

structure etched on surface by weathering, Thunder River Trail. 6, 

Asymmetrical anticlines in massive bed of sandstone, Wescogame Formation, near Apache Trail to Supai Village. Scale in inches. C, Convolute structure in massive sandstone of Wescogame on Apache Trail to 

Supai Village. Scale in inches. D, Penecontemporaneously downwarped 

bed of sandstone in Manakacha Formation, Parashant Canyon. E, 

Downwarped small-scale cross-strata among sandy limestone lenses of 

Manakacha Formation, Twin Springs Canyon. Arrows indicate areas of 

downwarp.
MINOR SEDIMENTARY FEATURES, CONTORTED STRUCTURES, HOMOGENEOUS SEDIMENTARY ROCKS 283

B

FIGURE N7.—Downwarps in massive sandy limestone, Grand Canyon, Ariz. A, Contorted structure in cliff unit of Manakacha Formation, Parashant Canyon. Vertical and horizontal distances in inches. 8, Contorted structure at 152 ft above base of Pakoon Limestone (McNair, 1951), Iceberg Canyon. 

Vertical and horizontal distances in feet. Drawing by W. L. Chesser from photographs.

The relatively few clear records of borings by organisms

that were noted in the samples examined make it seem "homogenous" sandstone deposits in the Supai Group. No 

unlikely that a complete reworking of the sand by bur- evidence of destruction of cross-strata by plant growth was 

rowing animals was responsible for any of the extensive observed.
284 THE SUPAI GROUP OF GRAND CANYON

EXPLANATION

Mudstone 

(deep red)

J_

1

FIGURF N8.—Compressional structures in foreset beds, Grand Canyon, Ariz. A, Rotated blocks, Manakacha Formation, east side of Whitmore 

Wash; B, high-angle folds, Wescogame Formation, Apache Trail to Supai Village. Vertical and horizontal distances in feet.
SEDIMENTARY FEATURES, CONTORTED STRUCTURES, HOMOGENEOUS SEDIMENTARY ROCKS 285

FIGURE N9.—X-ray radiographs of homogeneous 

sandstone, massive unit in middle of Esplanade 

Sandstone, Kaibab Trail, north, Grand Canyon, 

Ariz. Scale is natural size. Radiographs by W. K. 

Hamblin.

REFERENCES CITED

Aario, Risto, 1971, Syndepositional deformation in the Kurkiselkaesker, 

Kiiminki, Finland: Geological Society of Finland Bulletin 43, pt. 2, 

p. 163-172.

Alien, J.R.L., 1963, Asymmetrical ripple marks and the origin of waterlaid cosets of cross-strata: Liverpool and Manchester Geological 

Journal, v. 3, pt. 2, p. 187-236.

____1968, Current ripples—Their relations to patterns of water and 

sediment motion: Amsterdam, Netherlands, North-Holland Publishing Co., 433 p.

Conybeare, C.E.B., and Crook, K.A.W., 1968, Manual of sedimentary 

structures: Canberra, A.C.J., Bureau of Mineral Resources, Geology 

and Geophysics Bulletin 102, 327 p.

Hamblin, W. K., 1962, X-ray radiography in the study of structures in 

homogeneous sediments: Journal of Sedimentary Petrology, v. 32, 

no. 2, p. 201-210.

____1965, Internal structures of "homogeneous" sandstones: Kansas 

Geological Survey Bulletin 175, pt. 1, p. 3-37.

McKee, E. D., 1965, Experiments on ripple lamination, in Primary sedimentary structures and their hydrodynamic interpretation—A symposium: Society of Economic Paleontologists and Mineralogists 

Special Publication 12, p. 66-83.

__1966, Significance of climbing-ripple structure, in Geological

Survey Research 1966: U.S. Geological Survey Professional Paper 

550-D, p. D94-D103.

McKee, E. D., and Goldberg, Moshe, 1969, Experiments on formation 

of contorted structures in mud: Geological Society of America Bulletin, v. 80, no. 2, p. 231-244.

McKee, E. D., Douglass, J. R., and Rittenhouse, Suzanne, 1971, Deformation of lee-side laminae in eolian dunes: Geological Society of 

America Bulletin, v. 82, no. 2, p. 359-378.

McKee, E. D., Reynolds, M. A., and Baker, C. H., Jr., 1962, Laboratory studies on deformation in unconsolidated sediment, in 

Geological Survey Research 1962: U.S. Geological Survey Professional Paper 450-D, p. 155-159.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

Schuchert, Charles, 1918, On the Carboniferous of the Grand Canyon 

of Arizona: American Journal of Science, 4th ser., v. 45, no. 267, 

p. 347-361.

THE SUPAI GROUP OF GRAND CANYON

CLAY MINERALOGY

Chapter O 

By PHOEBE L. HAUFF and EDWIN D. McKEE

Contents

Page

Introduction ........................................................................... 289

Mineralogy ............................................................................. 289

Analytical techniques ................................................................. 289

X-ray diffraction analysis .......................................................... 289

Scanning electron microscopy ..................................................... 290

Petrographic microscope analysis ................................................... 290

Whole-rock composition ............................................................. 290

Clay mineralogy ................................................................... 291

Kaolinite ...................................................................... 291

Illite .......................................................................... 293

Chlorite ........................................................................ 293

Mixed-layer and random mixed-layer illite-smectite clays ................................ 297

Smectite ....................................................................... 301

Corrensite ...................................................................... 301

Distribution of clay minerals relative to rock type and composition ........................... ..... 302

Associations among the clay minerals ........................................................ 305

Origins and hypothesized depositional environments of the Supai clays ............................. 305

Random mixed-layer clays ............................................................. 308

Illitic clays ........................................................................ 308

Chlorite clays ..................................................................... 309

Corrensite .......................................................................... 309

Kaolinite .......................................................................... 311

Geographic distribution and possible relation to depositional environment .......................... 314

Watahomigi Formation .............................................................. 314

Manakacha Formation ............................................................... 315

Wescogame Formation ............................................................... 324

Esplanade Sandstone and Pakoon Limestone .............................................. 326

Summary ............................................................................... 328

References cited ........................................................................ 329

287
288 THE SUPAI GROUP OF GRAND CANYON

Illustrations

Page

FIGURE Ol. Graph showing percentage distribution of total clay minerals in rocks of Supai

Group .............................................................. 289

02. Diagram of mineral assemblages and principal nonclay minerals occurring in the

Supai rocks .......................................................... 291

03. Examples of X-ray diffraction patterns of several mineral assemblages identified

from the Supai Group ................................................. 292

04. Typical X-ray diffraction patterns for Supai Group clays illustrating the various

treatments used in the identification processes ............................. 294

05. Scanning electron microscope photographs of Supai Group clay minerals .......... 298

06. Graphs showing percentage distribution of clay minerals within the Supai Group

relative to rock type ............................ ................... 303

07. Graphs showing distribution of clay type against generalized mineral compositions

of the rocks within the Supai Group .... ......... ................... 304

08. Diagram showing hypothesized origins of the Supai Group clays ................. 306

09. Diagrams showing corrensite stability relationships ........................... 311

010. Scanning electron microscope photograph of kaolinite illustrating various criteria

for authigenic origin ..................... .......................... 312

011. Photomicrograph of potassium feldspar grain being altered to kaolinite . .. .. 314 

O12-O15. Color fence diagrams showing vertical distribution of clay minerals relative to 

lithologic facies within the:

012. Watahomigi Formation of the Supai Group ...................... . 316

013. Manakacha Formation of the Supai Group ...... .............. . 318

014. Wescogame Formation of the Supai Group ......................... 320

015. Esplanade Sandstone of the Supai Group .. ................... 322

016. Maps showing horizontal distribution of clay minerals within the Watahomigi

and Manakacha Formations ............................................ 324

017. Graphs showing distribution of clay minerals by numerical count within each formation of the Supai Group ............................................. 325

018. Graphs showing percentage distribution of clay minerals within each formation

of the Supai Group and relative to rock type ............... . .. ... 326

019. Maps showing horizontal distribution of clay minerals within the Wescogame Formation and Esplanade Sandstone ....................................... 327

Tables

Page

TABLE Ol. Compilation of literature references to corrensite-type minerals .................. 301

02. X-ray diffraction identification criteria for corrensite species ..................... 302

03. Sedimentary corrensite occurrences ........................................ 310
INTRODUCTION

CLAY MINERALOGY 

60

289

The Supai study presented an excellent opportunity to 

show how clay minerals can be useful as indicators of depositional environments. Within this Professional Paper 

exists petrographic, lithologic, paleontologic, mineralogic, 

and other information that assists in reconstruction of the 

geologic history of the Supai Group and its formations 

(ascending): the Watahomigi, Manakacha, Wescogame, 

and Esplanade. This study would not seem complete without an attempt to identify the clay minerals within this 

immensely fascinating and diverse suite of rocks and to 

integrate clay mineralogy data into a picture well defined 

by other geologic analytical techniques.

As a generalization, clay minerals seem to become less 

diverse and more stable with age (Weaver, 1957). Illite and 

chlorite, irrespective of host rock type, emerge as the dominant species for the Paleozoic, with only minor amounts 

of kaolinite and even less montmorillonite surviving the 

rigors of all that time. The Supai with its seven types of 

clay minerals, the major one being a highly unstable type 

of random mixed-layer (illite-smectite), presents an obvious and intriguing challenge. Initial plots of the clay data 

also indicated a high correlation between clay type and 

rock type; that is, those clays considered to be marine are 

found in marine type rocks, and clays considered to be 

continental are found in continental rocks.

This clay study was not meant to be exhaustive as it includes only about 700 samples from more than 15,000 mi2 

of the study area. The objective was to delineate general 

trends of the clay species and to associate these trends with 

the overall picture as developed from other available data. 

Good fortune came in the guise of the Supai itself, which 

seemingly has been little disturbed through vast lengths of 

time—300 m.y.—and has preserved, not in total entirety, 

but in significant quantity, a meaningful legacy from the 

past. In so doing, it has contributed to the reconstruction 

and interpretation of its own geologic history and depositional environments.

MINERALOGY

The clays studied in the Supai Group can be divided into 

seven distinct types. These include random mixed-layers 

(illite with various amounts of swelling clay), kaolinite, illite, chlorite, corrensite, mixed-layer (illite-smectite), and 

montmorillonite or smectite. Figure Ol shows their relative abundance in these rocks. The clay minerals comprise 

less than 5 percent by volume of the total rock composition 

and in most localities they form closer to 1 or 2 percent. 

For this reason, and also because of the relatively poor 

crystallinity of the majority of the samples, only a qualitative investigation was undertaken.

50 -

u 40

GC

30

20

10

	CLAY TYPE

RML Random mixed-layer

K Kaolinite

I Illite

Chl Chlorite

Corr Corrensite

Mont Montmorillonite

ML Mixed-layer

RML K Chl Corr Mont ML

FIGURE O1.—Graph showing percentage distribution of total 

clay minerals in rocks of the Supai Group including tongues of 

Pakoon Limestone (McNair, 1951) in the upper part of the 

Supai in the western part of the area, Grand Canyon, Ariz.

Samples were chosen on the basis of the whole-rock 

composition as previously determined by petrographic 

microscope examination. Pure quartz and pure carbonate 

rocks were avoided whenever possible as they probably 

were less hospitable to clay mineral development than 

were rocks of mixed composition. Although many rocks in 

carbonate sequences contained some clay minerals, those 

clays that were present in the very thick sequences of pure 

limestone or dolostone were in such miniscule amounts 

and so poorly developed that identification was marginal.

Analytical techniques

Identification of the various clay minerals was made primarily on the basis of X-ray diffraction analysis. This was 

supplemented by scanning electron microscopy (SEM). 

Elemental composition was verified with the energy dispersive system (EDAX) of the SEM. The petrographic 

microscope was also utilized in an attempt to determine 

textural relationships of the clays with associated minerals.

X-ray diffraction analysis

A method of qualitative X-ray diffraction analysis, 

routinely done at the U.S. Geological Survey was used in 

this study for the identification of the clay minerals. An
290 THE SUPAI GROUP OF GRAND CANYON

X-ray trace was first made on a randomly oriented, packed 

powder sample of the whole rock that was ground to about 

200 mesh. This trace gave an approximate idea of the principal clays present and also defined the mineral suite so 

that the necessary concentration and separation procedures could be determined. Mineral constituents of the 

Supai rocks that presented masking problems in the interpretation of the X-ray diffraction patterns were: the finegrained carbonates—calcite and dolomite—minor iron oxides in the form of hematite, and gypsum.

A 3-5 gram sample was crushed to free the less-than-2- 

micron fraction. A sonic probe was used to mechanically 

disaggregate the clay particles, and larger quartz and feldspar grains were removed by wet sieving. Using a variation 

on M. L. Jackson's (1974) method, the carbonates were removed from the samples. The powder was placed in a 

250-ml centrifuge bottle with a sodium acetate-acetic acid 

solution, buffered to a pH of 5. This was subjected to the 

sonic probe for 10 minutes and then put into a steam table 

and held just below boiling (about 90°C) for an average of 

8 hours. The time depended on the amount of carbonate 

present. The pH was restored toward neutral by washing 

with distilled water and centrifuging several times at a high 

(2,000) rpm (revolutions per minute) for 10 minutes. If the 

solution was allowed to remain too acidic, the clays would 

flocculate. A few drops of 10-percent ammonium hydroxide (NH4OH) assisted the suspension process. The iron oxides were not considered a sufficient interference to need 

removal. Gypsum was dissolved during the various water 

treatments.

Still in the centrifuge bottles, the clay samples were centrifuged for 3-5 minutes at 600 rpm to achieve suspension. 

This suspension was later pipetted onto unglazed, porous, 

ceramic tiles and air dried. Two tiles were made simultaneously for each sample to assure consistency in the following treatments.

Four X-ray diffraction runs were made per sample. The 

chart recorder was calibrated in such a fashion that these 

charts were physically stacked one above the other so that 

the reactions to the various treatments could be observed 

efficiently. The untreated sample was X-rayed first, then 

the tile was treated with ethelene glycol, and finally the 

tiles were heated to 400° and 500°C. A different color ink 

was used for each of the separate runs. A set of this type of 

diffractograms was made for each sample included in the 

study. Scans were made at 2 degrees two-theta per minute; 

chart speed of 1 inch per minute, which gives 2 degrees 

two-theta per inch. The target material of the tube is copper and at this scan speed with a 0.005 receiving aperature 

and 1° scatter and divergence slits, the diffracted radiation 

would be Cu Ka. The pulse height analyzer was set at 

1,000 counts per one second.

Scanning electron microscopy

Samples for scanning electron microscopy were chosen 

as a function of relative abundance of the clay mineral in 

the sample and also for highest degree of crystallinity. 

Some clay species are not commonly known for good 

resolution even under the high powers of the scanning electron microscope. From the X-ray traces of the Supai clays, 

it became apparent that good crystallinity was more of an 

exception than a rule in these samples. Even with careful 

concentration efforts many of the samples yielded small 

amounts of clay material. Only a cursory examination and 

a verification with the energy dispersive system could be 

made for many of the samples. Considering the length of 

burial time of these materials and the probable amounts of 

subsequent alteration, it is fortuitous that the few 

specimens of recognizable crystallinity survived to the 

present.

Because these materials were so fine grained, in the 1-2 

and less micron range, sample preparation for the SEM 

was difficult. The clay specimens would not take a uniform 

coating and had to be repeatedly coated with the goldpalladium alloy used to promote the conductivity of the 

samples. An antistatic preparation was also used to 

ultimately enhance resolution. Constant electronic 

manipulation was necessary to achieve and maintain 

resolution, especially at higher magnification. The very 

poor crystallinity of the majority of the samples, which 

was initially indicated by the X-ray analysis, was further 

emphasized by the SEM work.

The energy dispersive system was used as a qualitative 

indicator of the elements present and to verify the specific 

clay mineral being examined. Identifications from the 

powder patterns correlated with SEM analyses were made 

with confidence.

Because nearly all the samples contained iron oxides 

as grain coatings, the presence of iron within any of the 

clay minerals remained undetermined.

Petrographic microscope analysis

A selected number of thin-section slides was examined 

specifically to determine relationships of the clays to the 

associated minerals. The clays are so very fine grained that 

this method was not satisfactory. Some of the alteration 

relationships (feldspar to clays) were discernible. However, without the X-ray diffraction identifications, in the 

majority of the thin sections, it would not have been possible to determine which clays were present.

Whole-rock composition

The whole-rock composition of the Supai rocks has been 

presented in detail in other chapters of this publication.The 

mineral constituents of the clay samples were compiled as
CLAY MINERALOGY 291

a byproduct of the clay study from the X-ray diffraction 

traces. This information is useful as supporting data for 

differentiation of the two carbonate rocks present and also 

in determining, to some extent, which feldspars occur. The 

major application here of the clay mineralogy is as an indicator of diagenetic patterns of the clays.

From a compilation of the diffraction data, 10 mineral 

assemblages composed of five dominant minerals become 

evident and appear to represent the major mineral constituents in the study area. The minerals are quartz, calcite, 

dolomite, potassium feldspar, and another feldspar of indeterminate though probably albitic, composition. The 

assemblages and their interrelationships are shown in 

figure O2.

Examples of X-ray traces of these various combinations 

are given in figure O3. The patterns in this figure also illustrate the good crystallinity found within the Supai mineral 

suite, the typical relationships between the minerals, and 

the proportions of clay to nonclay. Identification of some 

feldspars is marginal, for it must be made on one or two 

peaks. In such marginal identifications the phase is merely 

labeled "feldspar." Only potassium feldspar can be identified as a discrete phase. Another feldspar was probably 

present in some samples. In the vast majority of the 

samples, however, this feldspar existed in such minute 

quantities that the precise identity was not discernible. The 

SEM energy dispersive system was used to determine the 

presence of the potassium and to substantiate the X-ray 

diffraction identification.

Hematite is present in nearly all the samples. The only 

other accessory mineral, gypsum, was restricted to the 

evaporite sequence in the Esplanade Sandstone. Heavymineral separations were not done on the samples. Any 

minerals present in amounts of less than 1 percent were 

therefore not detected nor considered pertinent to this 

study.

Clay mineralogy

Each of the seven clay minerals found in the Supai 

Group will be discussed separately relative to its response 

to the various analytical techniques used to identify it. The 

references from the literature defining each clay type are 

listed and the delimiting criteria are summarized.

Kaolinite

Kaolinite, in this study, is defined by using the presence 

of its 7k (001) and 3.57A (002) peaks on an oriented pattern. These peaks remained constant after glycolation and 

heating to 400°C, but vanished with 550°C heat treatment. 

Figure O4A illustrates the X-ray diffraction pattern from a 

typical kaolinite of the Supai suite. Most of these peaks 

were well defined, indicating good crystallinity. In some of 

the samples, where kaolinite was present in trace amounts, 

the crystallinity appeared to break down slightly as shown 

in figure O4B.

Quartz Quartz Feldspar

F

:

Quartz Feldspar Dolomite

ELDS PA

OLOMIT

CD

£! ® Q- t_ .t; w

CD 0 T3

oc3£

}

E

M <D 

t .~ 

5"TMCD 0

oo

HUARTZ

Quartz Calcite 

K-Feldspar

CALCITE

K-FELt

Quartz Calcite 

Dolomite K-Feldspar

DSPAR

0

a «!

ro'o 0

3 CD O

OOQ

DOLC

Quartz 

Dolomite

)MITE

Dolomite

FIGURE O2.—Mineral assemblages and principal nonclay minerals occurring in the Supai rocks,

Grand Canyon region, Arizona.
292 

A

THE SUPAI GROUP OF GRAND CANYON

D n

Q

Q

K-Chl

Chl

30 20 10 4

B

KDol

par

Q

I Chl

40 30 20 10 4

Q

Cal

sp Cal

Q

ML

Fsp

Q Q

Chl

30 20

Dol

V

\_ 

50

10 4

Ca

: sp

Cat 

H ML

40 30 20 10 4

Cal

ML

ML F

50 40 30

Dol

Q

Cal ML

20 10 4 40 

DEGREES 2-THETA

30 20 10 4
CLAY MINERALOGY 293

The kaolinite samples were the best specimens in the 

suite for definitive SEM analysis as a function of grain size, 

of better crystallinity than other clays present, and of stilldiscernible crystal habit.

Figure O5B is representative of the average appearance 

of kaolinite samples as viewed by the SEM. The ED AX 

spectra for this sample showed high alumina and silica. 

Without the substantiating X-ray diffraction analyses and 

some hint of crystal morphology, kaolinite cannot always 

be identified positively. Considering the potential time 

factors involved, it is understandable that even stable 

kaolinite shows clearly the ravages of time and alteration 

processes. Possible authigenic criteria, on the basis of SEM 

pictures and photomicrographs, will be discussed in a later 

section of this chapter.

Illite

Following the definition of Gaudette, Eades, and Grim 

(1966), illites identified in this study are those 10A clay 

minerals that do not expand upon glycolation. Figures O4B 

and O4C show, by X-ray diffractograms, that typical illites 

of the Supai Group just barely conform to this criterion. 

They better fit the theories of Velde (1966) and Rex (1966) 

that all illitic clay types contain some degree of 

mixed layering. Applying the nonexpansion criterion can 

become a function of choice of scale factor on the pulse 

height analyzer of the X-ray machine.

In the suite of Supai Group clay samples, a total gradational spectrum exists from a 10A nonexpanding "illite" 

through varying percentages of mixed-layer (illitesmectite), and random mixed-layer (illite-smectite) 

configurations. The X-ray diffraction pattern is relatively 

consistent. The 10A peak, unless of a highly random 

mixed-layer composition, is steep toward the low 

angstrom values, but asymmetrical toward high angstrom 

values. The asymmetry is a direct function of increasing 

mixed-layer content. The more illitic a sample is, the better

FIGURE O3 (facing page).—Examples of X-ray diffraction patterns of 

several of the mineral assemblages identified from the Supai Group, 

Grand Canyon, Ariz., including tongues of Pakoon Limestone (McNair, 

1951) in the upper part of the Supai in western Grand Canyon. Q, 

quartz; Cal, calcite; Dol, dolomite; H, hematite; Fsp, feldspar; I, illite; K, 

kaolinite; Chl, chlorite; ML, mixed-layer clay; K-spar, potassium feldspar. 

Scale is in degrees two theta. A, Quartz with kaolinite, chlorite, and 

hematite. B, Quartz, dolomite, and potassium feldspar with illite, 

chlorite, and hematite. C, Quartz, calcite, and feldspar with mixedlayer clays. D, Quartz and feldspar with chlorite, illite, and hematite. E, 

Quartz, calcite, dolomite, and feldspar with kaolinite, mixed-layer 

clays, and hematite. F, Quartz, calcite, dolomite, and hematite with 

mixed-layer clays.

crystallinity it possesses. Except in samples of total random 

mixed-layer composition, the 10A peak is mostly sharp, indicating that the illite phase is dominant.

Illite in the Supai Group is extremely fine grained, and 

even very high SEM magnification fails to resolve individual grains. Figure O5C shows a typical specimen configuration for illite. This curved-festoon type of habit was found 

throughout the samples. Several types of surface textures 

were observed at magnifications from x 8,500 (figure O5D) 

to x 12,000. The EDAX spectrum showed aluminum, silicon, potassium, and, in some samples, very minor 

calcium. This was consistent for all samples examined.

Chlorite

Chlorite in the Supai rocks occurs almost exclusively in 

trace amounts. For this reason, only its presence, and not 

its species, can be indicated. Figure O4D shows an X-ray 

diffractogram of an illite-chlorite-bearing sample. Even 

more typically, the existence of chlorite in a sample commonly is substantiated by the appearance of a 14A peak on 

the 400°C or 550°C pattern. The apparent crystallinity of 

the 14A and 7A peaks in almost all specimens is poor. The 

peaks are broad or just barely discernible. In some samples, peak resolution is improved with heating. On the 

basis of the criteria established by Hayes (1970), the 

speculation can be made that this is a type I chlorite 

polytype; formed at low temperature, fairly unstable, and 

possibly authigenic in origin. Sample restrictions and low 

concentration of the chlorite phase made it impossible to 

determine the diagnostic hOl reflections required to identify poly types.

Figure O5F illustrates a habit common to the samples 

scanned. The very high magnifications emphasize the fine

FIGURE O4 (following pages).—Typical X-ray diffraction patterns of clays 

from the Supai Group and Pakoon Limestone (McNair, 1951) tongues in 

western Grand Canyon illustrating various types of clay minerals and 

the treatments used in their identification. Scale is in degrees two theta. 

A, Kaolinite as the major clay present and showing good crystallinity. 

8, Kaolinite as a trace amount showing poor crystallinity. Illite is the 

major clay present. C, Illite as the major clay showing slight mixed-layer 

(illite-smectite) configuration. D, Chlorite and illite. £, Chlorite containing some expansive layers. F, Mixed-layer clay composed of illite and 

smectite. G, Mixed-layer clay composed of illite and smectite with a 

hydration layer. H, Transitional mixed-layer clay. /, Random mixedlayer clay (illite-smectite) showing shift of 5A peak with glycolation and 

estimate of percent expansible layers. I, Graphical representation of 

Reynolds and Hower (1970) method for determining percent expansible 

layers present. K, Smectite. L, Corrensite. M, Corrensite-related mineral; 

shows expansive layers. N, Totally random mixed-layer phase; probably 

illite-smectite.
294 THE SUPAI GROUP OF GRAND CANYON

26 24 22 20 18 16 14 12 10

10A

Quartz

DEGREES

24 22 20 

2 - T H E T A

16 14

FIGURE O4.
CLAY MINERALOGY 295

Glycolated

Untreated

22 20 18 16 14 12 10 8 6 4 2

Chlorite and 

expansive layers

Illite phase

Hydration layer

Smectite 

phase

24 22 20 18 16 14 12 10 8 6 4 2

Quartz

10A

24 22 20 18 16 14 12 10

H

Quartz

642 24 22 20 18 16 14 12 10 

DEGREES 2-THETA

642

FIGURE O4—Continued.
PERCENT EXPANSIBLE

8.

o _
CLAY MINERALOGY 297

M

400°C

26 24 22 20 18 16 14 12 10 6 4

24 22 20 18 16 14 12 10 8 6 4 

UNITS ARE IN DEGREES 2-THETA

FIGURE O4—Continued.

grain size of the mineral. The ED AX spectra showed silicon, aluminum, magnesium, titanium, and iron(?).

Petrographic microscope examination indicated isolated 

detrital chlorite grains mostly in sandstone or arkosic 

matrices. This observation probably explains some of the 

anomalous associations of the chlorite samples in the continental rocks.

The X-ray diffractogram (fig. O4E) for figure O5F shows 

a possible transition from pure chlorite to a more mixedlayer mineral, a possible corrensite-type. There is a swelling chlorite layer developed here, as shown by the expansion from 14A (untreated) to IsA with glycol and the 

collapse to the 14A chlorite position with heat. Because 

iron is ubiquitous in these samples and there are not sufficient basal peaks present, whether this is a dominantly

magnesium chlorite or an iron chlorite could not be determined conclusively.

Mixed-layer and random mixed-layer 

illite-smectite clays

Clay minerals of the Supai illustrate a transitional sequence from smectite through mixed-layer (illite-smectite), 

or random mixed-layer (illite-smectite), possibly to illite. 

This is a gradational sequence and some steps in the progression can be seen starting with figure O4/, a fully 

expanded smectite; to figure O4F, a mixed-layer (illitesmectite) with incomplete expansion to only 15.5A, with 

glycol; to figure O4G, which shows a mixed-layer (illitesmectite) with a hydration layer developing; to figures 

O4H and O4/, both of which illustrate the transitional random mixed-layer (illite-smectites) phases that are so prevalent throughout the Supai.

Mixed-layers of illite and smectite-type layers in this 

study are defined as those clays that show discernible 10A 

and 14A peaks in the untreated sample; show expansion of 

the 14A peak anywhere up to 17A, but no 10A expansion 

under glycolation; and collapse to 10A and intensification 

or sharpening of peaks with heat. The criterion of Reynolds and Hower (1970) to estimate an approximate percentage of smectite layers present was applied whenever 

it was possible to measure the shift in the glycolated 5A 

peak position. Determining an exact value was complicated by the fact that, with glycol, the more randomness 

involved, the broader the 5A + peak, and percentages 

subsequently became approximate. Because the Supai 

samples were not as well defined as the samples used by 

Reynolds and Hower (1970), some additional interpolation 

was necessary.

A random mixed-layer clay, in the present study, is 

probably composed of degraded illite-mica with expansible 

layers; shows a loA peak with moderate to extensive asymmetry toward the high angstrom values in the untreated 

sample; expands upon glycolation into a broad, poorly 

defined "peak," from 10 to 17A, which may show separation, be concentrated near the loA area, or merely show a 

higher background hump from 10A upward; and collapses 

again asymmetrically about the 10A position with heat.

Using a loose interpretation of Reynolds and Hower 

(1970), these random mixed-layer type patterns are interpreted to indicate the presence of a dominant 10A phase, 

which can be termed a degraded mica or illite accompanied 

by randomly stratified expansible layers of smectite derivation. The majority of the samples labeled "random 

mixed-layers" in the present study conform to the above 

criteria and appear to contain less than 25 percent expansible layers. Subsequently, it is hypothesized that a detrital 

mica in the source rock is being degraded to the mixedlayer phases. Figure O4/ is an illustration of the shift in the
298 THE SUPAI GROUP OF GRAND CANYON
FIGURE O5.—Scanning electron microscope photographs of Supai 

Group clay minerals. Localities are those of measured sections (fig. A1); Grand Canyon, Ariz. A, Kaolinite; Prospect Valley, Wescogame Formation; x 8000. 6, Illite; S B Canyon, Manakacha Formation; x 680. C, IIlite; Whitmore Wash, Watahomigi Formation; x 8500. D, Authigenic chlorite flake; Andrus Canyon, Watahomigi Formation; x 20,900. £, Chlorite; Separation Canyon, Watahomigi Formation; x 17,200. F, Random mixed-layer clay bordering on illite; Andrus Canyon, Esplanade 

Sandstone; x 1000. G, Possible smectite flakes; Tuckup Canyon, Manakacha Formation; x 23,500. H, /, Corrensite-bearing sample; Andrus Canyon, Watahomigi Formation; x 21,400 (H) and x 9400 (/).
FIGURE OS-Continued.
CLAY MINERALOGY 301

5A peak showing the 5.0A position of the 10A illitic component with the 5.18A shifted peak of the expansible layer 

component. Figure O4/ is a fitted curve of the values given 

in Reynolds and Hower (1970); the 5.18A position indicates about 23 percent ^expansible layers present.

Figure O5G is an SEM photograph of a random mixedlayer (illite dominant) sample. The illite habit of previous 

illustrations (O5C and O5D) is clearly evident, but another 

phase, probably smectite, is also present. The poor crystallinity and the fine grain size suggested by the X-ray diffraction patterns is confirmed by this photograph (fig. O5G), 

which reiterates the proposed degraded mica origin by 

showing the dominant illite phase.

Smectite

Smectite is sparsely dispersed as a discrete phase in the 

Supai Group. It is characterized by a strong, well-crystallized 14A peak in the untreated state. This expands to 17A 

upon glycolation and, with heat, loses water and collapses 

to 10A (Carroll, 1970). Figure O4K is a diffractogram of 

Supai smectite. ED AX analysis and the untreated 14A peak 

position indicates the Supai smectite to be primarily the 

common dioctahedral variety. This smectite is very fine 

grained and subsequently undetectable as discrete grains 

with the optical microscope. Even with the SEM, very high 

magnifications (x 23,100) were necessary to resolve crystal 

habit, and the success of that procedure is questionable. 

Figure O5H is an SEM photograph of a montmorillonitebearing sample. The ED AX indicates the presence of silicon, aluminum, calcium, and potassium. The flakes in this 

photograph are less than 1 micron in size.

Throughout the entire Supai suite there are less than 10 

samples containing smectite. For reasons of time and depth 

of burial, smectite generally does not survive in rocks older 

than Mesozoic age, nor in deeply buried sediments (Hower

and others, 1976; Van Moort, 1971; Perry and Hower, 

1970; Burst, 1959; Weaver, 1957, among others). The 

Supai study seems to add further credence to this theory. 

There is such an insignificant amount of smectite in Supai 

rocks that its existence is reported, but its presence should 

be integrated with great care into the whole Supai history. 

The smectite found in the Supai probably is a product 

of surface weathering and is not related to the ancient 

environments.

Corrensite

The exact nature of corrensite is the subject of considerable discussion and disagreement in the literature. There 

are three different descriptions of this mineral cited in the 

literature. Table Ol lists some of the references for each 

type.

Table O2 shows how each of the three types generally 

responds to the standard clay analyses methods.

The swelling-chlorite variety expands with glycol but 

does not collapse with heat; the montmorillonite type both 

expands and collapses; the vermiculite layer does not expand but collapses. Each of these appears to be a distinct 

species.

The literature is in agreement that, in general, "corrensite" is a 1:1, regular, interstratified species composed of a 

chlorite layer and a swelling-clay layer. Disputation arises 

when the swelling layer is characterized. Brucite sheets of 

the swelling layers may be incomplete and weakly bonded, 

resulting in preferential removal of parts of the sheets. 

Hydroxyl ions surround magnesium in the brucite sheet. 

Introduction of hydronium ion into the system converts 

the OH~ to H2O, weakening the structure and freeing the 

Mg + 2 which can then be exchanged from the structure. 

The resulting "island" or "pillar" configuration is not 

strong enough to oppose introduction of polar molecules,

TABLE O1.—Compilation of literature references to corrensite-type minerals

Chlorite-swelling chlorite Chlorite-montmorillonite Chlorite-vermiculite

Honeyborne (1951).

Stephen and MacEwan (1951).

Lippman (1954).

Martin-Vivaldi and MacEwan (1957, 1960).

Heckroodt and Roering (1965).

Wilson and Bain (1970).

Sawatzki (1975).

Honeyborne (1951).

Sudo and Matsui (1954).

Earley and others (1956).

Sudo (1959)

Wilson and Bain (1970).

lijimaand Utada (1971).

Tardy, Krempp, and Trauth (1972).

Tomasson and Kristmannsdottir (1972).

Blatter, Roberson, and Thompson (1973).

Kimbara (1973).

Kimbaraand Sudo (1973).

Sawatzki (1975).

Lippman (1976).

Bradley and Weaver (1956).

Lippman (1956).

Alietti (1958).

Melnik (1959).

Harvey and Beck (1960).

Peterson (1961, 1962).

Bodine (1971).

Rao and Bhattacharya (1973).

Koppand Fallis (1974).

Furbish (1975).
302 THE SUPAI GROUP OF GRAND CANYON

TABLE O2.—X-ray diffraction identification criteria for corrensite species

Type

Chlorite-swelling-chlorite . . 

Chlorite-montmorillonite . .

Untreated

2£A 

28A 

28A

Ethylene 

glycol

31A 

31A 

28A

550° C

28A 

24A

24A

Spacings

14A+14A = 28A 

14A+14A = 28A 

14A+14A = 28A

such as glycol, into the structure causing the subsequent 

swelling that occurs from their presence. However, sufficient integrity still remains to prevent collapse to less than 

12A with heat, subsequently giving a characteristic 

physical response that defines corrensite in a clay analyses 

technique. The preceding theory from Martin-Vivaldi and 

MacEwan (1960) is a simplified version of the degradation 

hypothesis.

From the work of Lucas and Ataman (1968) and from 

that done by Lucas (1962), Millot, Lucas, and Wey (1963), 

Millot (1964), and Millot, Lucas, and Paquet (1966) came 

the hypothesis of corrensite formation by aggradation of 

random mixed-layer phases in a magnesium-enriched 

environment. The "equivalence" theory that Powers (1959) 

developed explains the preferential adsorption of magnesium,over potassium when the ratio of the [Mg2 + /K+ ] is 

about 5 to 1 in seawater. Not only will the magnesium be 

absorbed into the degraded material, but it will unite with 

free silica tetrahedra. With this incorporation of magnesium into the lattice, water is lost and a rearrangement to a 

higher level of ordering results in a decrease of expansible 

layers. This theory involves ion migration from the surrounding solutions to interlayer cation positions and then 

to the octahedral layer sites and finally to the tetrahedral 

layer sites (Millot, Lucas, and Paquet, 1966). This is a 

diagenetic process that can be followed from detrital random mixed-layers through a corrensite phase to a wellcrystallized chlorite (fig. O8).

An untreated Supai corrensite sample gave major basal 

spacings at 29.0A, 14.sA, and 7.2A. With glycol these 

spacings expand to 31.oA(5 ), 15.sA, and 7.75A, respectively; at 550, C they collapse to 24A, 12A, and 6A, respectively. Such values are in agreement with data in the literature (Lippmann, 1956, 1976; Honeyborne, 1951; Bradley 

and Weaver, 1956; Peterson, 1961; and Almon and others, 

1976).

Figure O4L shows an X-ray diffraction pattern typical of 

a Supai specimen of corrensite. The corrensite phase is not 

always present in large enough amounts in the Supai 

Group to show all the major basal spacings, but the 

definitive 7A and 14A peak shifts could be characterized 

and followed through the various treatments. The peaks 

were always sharp and well defined, indicating good crystallinity. All the corrensite samples reacted consistently to

the treatments, expanding and collapsing to the required 

values.

Figures O4E and O4M are diffraction patterns for a 

corrensite-related mineral. This clay, which is generally in 

close stratigraphic association with the corrensite, reacts 

differently to the various treatments. The expansion with 

glycol is about the same as ISA versus 15.sA for corrensite; 

but this clay does not collapse with heat as far as does corrensite. The implication is that this phase has fewer gaps in 

the brucite layer, has less water replacing the hydroxyls 

and, therefore, is a transitional species between corrensite 

and chlorite. The existence of this phase strongly suggests 

that the mixed-layer configuration of the corrensite is 

upgrading toward a nonexpanding chlorite, supporting the 

aggradation theory and corresponding with the theory presented by Dunoyer de Segonzac (1970). See also figure O8.

Figures O5/ and O5/ are SEM photographs of corrensitebearing samples. They are unsatisfactory in terms of resolution, but they do illustrate the mixed-layering nature of 

this species.

DISTRIBUTION OF CLAY 

MINERALS RELATIVE TO ROCK 

TYPE AND COMPOSITION

The geographic, stratigraphic, and lithologic distributions of the clay minerals in the Supai Group furnish 

evidence of the origin of the Supai clays. This part of the 

chapter will discuss briefly these distribution patterns and 

generally relate them to the origins of the various clay species. The distribution of the seven clay mineral species— 

kaolinite, random mixed-layer, mixed-layer (illitesmectite), chlorite, illite, corrensite, and smectite—relative 

to general rock types is shown in figure O6. The dominant 

clay of the suite is the random mixed-layer type. This 

species, or its immediate antecedent, is probably detrital in 

origin. It is the major clay throughout all the rocks thought 

to be continental. It is uncommon in the dolostone and 

limestone. It may not have been transported far enough 

into the marine environment to accumulate as the dominant species or it may have undergone subsequent
CLAY MINERALOGY 303

70

60

50

40

30

20

10

SANDSTONE

70

60

50

40 -

30 -

20 -

10 -

SILTSTONE

70

60

50 -

20 -

10

Q RML K I Chl Corr S ML RML K I Chl Corr S ML RML K I Chl Corr S ML

MUDSTONE

bU

40

30

20

10

n

-

-

-

- ||

ljs£?&

PS

11

LIMESTONE

1 1

1, cJ

If I

si|j

H II ^ in

DOLOSTONE

RML Chl Corr ML

CONGLOMERATE

RML K Chl Corr ML RML K I Chl Corr ML

FIGURE O6.—Percentage distribution of clay minerals within the Supai 

Grand Canyon relative to rock type. RML, random mixed-layer; K, 

layer.

diagenesis toward an illite phase. The latter premise can be 

supported to some degree by the large amount of illite 

present in the marine rocks and also by the evidence seen 

in the X-ray diffraction patterns as discussed in the prior 

section; the illitic phase of the random mixed-layer clays 

seems better developed in the marine environment.

Kaolinite is the most abundant of the clays believed to be 

potentially authigenic. It predominates in the sandstones, 

mudstones, siltstones, and conglomerates, indicating a 

probable continental environment of formation. Where 

kaolinite occurs in limestones and dolostones, local facies 

change to a nonmarine rock type is commonly described 

(see measured sections). Such data indicate that the clay 

mineral types are consistent with depositional environment.

The illite, chlorite, and corrensite clays are more common in marine rocks than in rocks considered to be of continental origin. Most of the chlorite observed in sandstones 

is thought to be detrital. Although the close numerical relationship of chlorite to corrensite in several of the rock

Group and the intertonguing Pakoon Limestone (McNair, 1951) in western 

kaolinite; I, illite; Chl, chlorite; Corr, corrensite; S, smectite; ML, mixedtypes may be coincidental, it may also indicate a common 

origin. What seems to be an anomalous occurrence of 

marine clays in the nonmarine siltstone probably is the 

function of a local facies.

Because of its lack of a distinctive distribution pattern, 

the mixed-layer clay mineral might be detrital or possibly a 

diagenetically upgraded form of another clay species.

Montmorillonite is too insignificant in the sample suite 

to discuss any possible relationships it may have to the 

origins of the Supai.

Figure O7A shows the distribution of clay type versus a 

generalized mineral composition from the whole-rock 

X-ray analyses. All the clay minerals appear to be present 

in greatest amounts in a rock with quartz, feldspar, and 

carbonates (type B). Fortunately, rocks with all these constituents compose 74 percent of the total samples analyzed, 

whereas type A (quartz and feldspar) is only 6 percent, and 

type C (quartz and carbonates) is 19 percent of the total 

suite. Illite, chlorite, and corrensite do occur in greater
304 THE SUPAI GROUP OF GRAND CANYON

80

70

A

70

60

TYPE B

60 50

50 40

40

30

20

30

20

21.6

10

10

RML I Chl Corr ML

6.5 5.9

4.7 3.4

RML K I Chl Corr ML

y 70

D 

CO

cc

CO 60 

Q

50

40

30 -

20

10 -

66.7 B

TYPE A

15.4

7.7

70

60

50

40

30

20

10

5.1

2.6 2.6

D

TYPE C

50.9

8.2

6.4

3.6

RML K I Chl Corr ML RML K I Chl Corr ML

FIGURE O7.—Graphs showing distribution of clay type against generalized mineral compositions of the rocks 

within the Supai Group, Grand Canyon, Ariz. Tongues of Pakoon Limestone (McNair, 1951) are included in the 

upper part of the Supai in western Grand Canyon. Rock compositions are: type A, quartz and feldspar; type B, 

quartz, feldspar and carbonates; type C, quartz and carbonates. Clay types are: RML, random mixed-layer; K, 

kaolinite; I, illite; Chl, chlorite; Corr, corrensite; ML, mixed layer. A, Clay type against composition of rocks; B, 

clay types within type A rocks (39 samples); C, clay types within type B rocks (430 samples); D, clay types within 

typeC rocks (110 samples).
CLAY MINERALOGY 305

quantity in the more marine type C than does the hypothesized continental kaolinite.

An even more detailed breakdown is given in figures 

O7B, C, and D. The distribution of kaolinite is a little ambiguous from these data. The marine clays, however, are 

relatively consistent in favoring the carbonate facies over 

the probable continental quartz and feldspar rocks. The 

random mixed-layer clay is also significantly less in the 

marine rocks.

ASSOCIATIONS AMONG 

THE CLAY MINERALS

Distinct patterns of clay-mineral association occur in the 

Supai Group sedimentary rocks. Random mixed-layer 

clays frequently occur discretely without other clay 

minerals. Kaolinite, in minor amounts, is commonly associated with random mixed-layer clays. Chlorite, in trace 

amounts, is also found with the random mixed-layer clays. 

Corrensite has not been observed in direct association with 

the random mixed-layer clay type. Illite may occur with 

random mixed-layer clays, but it is usually the dominant 

clay phase where the two are associated.

When kaolinite is relatively abundant in a rock, there is 

rarely another clay mineral associated with it. In some 

places it occurs with mixed-layer clays and, infrequently, 

with chlorite. If kaolinite and illite are found together, 

the illite is usually degraded. A corrensite and kaolinite 

association has not been observed, agreeing with Velde's 

observations (1977b). Corrensite and illite occur together 

exclusive of other clay minerals. Chlorite is usually present 

with illite, but illite is not necessarily accompanied by 

chlorite.

Kaolinite, illite, and montmorillonite locally occur by 

themselves, but this is not the usual pattern. Chlorite 

usually occurs as an accessory clay phase. Mixed-layer 

clays and montmorillonites are present in such minor 

amounts that a recognizable pattern of distribution has not 

been established for them.

ORIGINS AND 

HYPOTHESIZED 

DEPOSITIONAL 

ENVIRONMENTS OF 

THE SUPAI CLAYS

Reconstructing the possible depositional environments 

of clay minerals, some of which are possibly 300 million 

years old, is to some degree highly speculative. However,

this study is based on considerable data in the form of 

X-ray diffraction analyses, scanning electron microscope 

photographs, and energy dispersive elemental determinations, with the paleogeographic, lithologic, and mineralogic distributions and associations already presented in 

previous chapters, and with prior research documented in 

the literature. All this can at least allow for an educated 

speculation. Several explanations are possible for the 

origins of the clay minerals in the Supai Group. The 

authors have chosen that explanation which appears to be 

the simplest, yet which incorporates most of the data with 

the fewest apparent contradictions.

Definition of the terms detrital, authigenic, and diagenetic, as used in the following discussion, is required to 

ensure a general understanding. "Detrital" indicates an 

origin other than the rock in which the mineral is found; it 

infers transport from another area before deposition. 

"Authigenic" is defined as formed or generated in place; a 

mineral that has not been transported but rather formed 

where it occurs, and at the time of or very shortly after 

deposition of the rock. "Diagenetic" as it will be used in 

this context refers to processes of formation subsequent to 

deposition and implies a passage of time during which 

these processes may operate. These definitions have been 

taken from the Glossary of Geology (American Geological 

Institute, 1972). Millot, Lucas, and Wey (1963) further refined the term "diagenetic" by defining it as transformations that take place within the sediments after sedimentation but before low-grade metamorphism. Unfortunately, 

the transition between "authigenic" and "diagenetic" is not 

always apparent.

Judging by evidence derived from the clay minerals, the 

Supai has led a rather structurally quiet existence through 

time. The temptation is great to follow the theory of burial 

diagenesis presented by Burst (1959, 1969), detailed by 

Powers (1967), and refined by Perry and Hower (1970) and 

by Hower and others (1976). Although the montmorillonite-mixed layer-illite configurations are present and the 

time factor certainly is viable, sufficient depth of burial to 

generate the necessary temperature-pressure gradient for 

burial diagenetic transformation apparently is lacking. 

There is also not sufficient ordering to the mixed-layer 

clays for any great depth of burial (Hower, 1967). There is 

no direct evidence that montmorillonite could have been 

the precursor of the random mixed-layer species. The 

interrelationships of the clays are more of a horizontal 

nature than of the vertical type, which would be more suggestive of burial diagenesis. However, many of the reactions illustrated in that process are most helpful in 

reconstructing the history of the Supai. Figure O8 diagrammatically shows the hypothesized origins of the Supai 

Group clays. The general theory of the depositional conditions of these clays will be presented and each species 

and its interactions with the whole will be discussed.
306 THE SUPAl GROUP OF GRAND CANYON

SOURCE 

detrital micas, 

illites, chlorites, 

mixed-layer clays

some K"1" removed

acidic environment 

T-<100° C

->

i/

SOURCE 

detrital mica, 

potassium feldspar 

smectite

CONTINENTAL

^> i^ 

acid leaching high Al source

carbonic 

organic 

material phase <150°C

K Al3 Si3 010 (OH)2

FIGURE O8.—Diagram showing hypothesized
CLAY MINERALOGY 307

> remain in RML 

configuration

—— 75°C

K+ leached

associates with

diagenetic

10A phase upgraded QR

swelling layers 

<100°C

10A phase tetrahedral on_Rno/ 

upgraded Al3- * layer 30~5°:°

ss expansible I ___

QUARTZ

i-' +

QUARTZ

Mg (OH) layers 

start to form K ,

Al3 -*^X\A

tetrahedral layers Xl\ 

,^oiw« swelling layers lost ^

I -^ . — _, p». .„.„.„ | ^

1^ H

CHLC

- ——— high KVH+ 

)RITE

ILLITE

K+ >Mg

pH<7.0

expansible layers 

(degraded) -100°C

dolomite,

sea water concentrate, 

degraded Mg-bearing minerals

.- i ** /-M_I partial Mg OH

layers built £

100°C

in saline;

~- M a ich environments

end product is regular

mixed-layer

pH ~ 7.5-8.8

V

transitional 

phase (minor 

mixed layer)

H4Al2Si2 O9 

continental 

"authigenic"

origins of the Supai Group clays.
308 THE SUPAI GROUP OF GRAND CANYON

Random mixed-layer clays

The abundance and completely general distribution of 

the random mixed-layer clays, irrespective of lithology or 

paleogeography, led to the conclusion that they are detrital 

in origin. Rather than smectite, as in the burial diagenesis 

theory, the random mixed-layer clays have probably been 

derived from detrital micas and clay phases; they have 

been transported and stripped of sufficient potassium to 

degrade them to their present state. A definite trend 

toward the lost potassium reestablishing itself, with the 

10A phase taking some precedence, occurs in the marine 

facies. The interlayer sites of an illitic-type structure tends 

to concentrate potassium (K+ ) because it is both abundant 

and a cation most easily dehydrated (Hower and others, 

1976). A lower layer charge to dehydrate potassiumbearing layers is required. These layers therefore lose 

water faster and collapse toward an illite (Eberl, 1978; 

Eberl and Hower, 1977). The greater abundance of illite 

over the random mixed-layer clays in the marine facies is 

considered a further indication that potassium fixation has 

occurred within the random mixed-layer species of the 

Supai, upgrading them to illites or to dominantly illitetype phases. This non-aggradation was discussed by 

Weaver (1956).

The random mixed-layers of those rocks considered to 

be continental, however, show a lack of consistent crystalUnity. This factor could indicate that there was a minimum 

amount of diagenetic activity in the continental environment after deposition. A most useful diagram relating subsurface temperature to percent of expansible layers is 

shown by Perry and Hower (1970, p. 175). This diagram 

indicates that random mixed-layer phases are stable up to 

75°C; regular interlayered species can exist from 75° to at 

least 100 C and possibly, but in smaller percentages, at 

slightly higher temperatures. Perry and Hower (1970) emphasized temperature rather than depth of burial as the 

dominant agent of diagenesis. The investigations of Van 

Moort (1971) pointed out that at temperatures of about 

105°C, the next to the last water interlayer of a mixed-layer 

species is removed. Velde (1977a), in his compilations, 

mostly agreed with these temperature parameters. He also 

hypothesized a solid-solution series from smectite through 

various mixed-layer phases (lower temperatures giving 

more random structures) to illite. His experiments with 

Bystrom-Bruzewitz (Velde and Bystrom-Bruzewitz, 1972) 

presented additional evidence. In general, these investigators concluded that random mixed-layers occur at 

low temperatures—usually less than 100°C; that if there is 

potassium in the environment, it will migrate into the 

structure, upgrading it toward a mica; and that not much 

energy is required for this process to operate. This progression is in agreement with the comprehensive summary of 

Dunoyer de Segonzac (1969, 1970). He presented two

paths of formation for intermediate-mixed layer clays: (1) 

If potassium and sodium ions are introduced into the lattice of random mixed-layer clays, regular mixed-layer clay 

evolves; with additional K + and Na + illite forms and with 

metamorphism becomes a mica. (2) A magnesiumenriched environment may produce a corrensite mixedlayer upgrading through transition phases into a chlorite. 

All these various phases and transitions between them are 

observed within the Supai Group.

Illitic clays

The preceding discussion leads logically to the illites in 

the Supai. The X-ray diffraction patterns indicate that even 

the most crystalline of the illites have some minor expansive material in them. Temperatures and pressures comparable to low-grade metamorphism may be required to 

change mixed-layer phases completely toward a "pure" illite (Weaver, 1957; Hower and Mo watt, 1966). The distribution diagrams (fig. O6) for the clay minerals show 

illite nearly confined to limestone and dolostone (marine 

environment) in the Supai. The few probable continental 

facies that carry illite, upon close examination, mostly are 

found to have local marine connections. Illite associates 

primarily with other probable marine clays such as chlorite 

and corrensite. When it does occur with kaolinite, the illite 

shows signs of degradation as though it had been partially 

leached of its potassium content. In its association with 

random mixed-layers, illite is the dominant phase and the 

occurrence is within definitely marine rocks.

Illite is frequently a clay of marine environments, favoring carbonate facies, and also enjoying dominance over 

other clay types in ancient sediments (Millot, 1949; 

Weaver, 1957; Tooker, 1960; and Grim, 1968). Brooks and 

Ferrell (1970) and Velde (1977b) noted that with increasing 

salinity illite becomes more stable and that in a fluviatile 

environment it is unstable. The chemical transformation 

that creates illite is discussed in various details by Powers 

(1959), Weaver and Beck (1971), Weaver and Pollard 

(1973), Hower and others (1976), Reesman and Keller 

(1967), and Harder (1974).

Illite forms in waters having a high [K+ /H+ ] ratio 

(Garrels and Christ, 1965). For it to become stable, the 

potassium ion must be fixed within the structure. This requires an increase in the net interlayer charge of the expanded layers. These layers do not convert to a nonexpansive state merely with an influx of potassium. The A13+ is 

replaced by Mg2+ or Fe3+ in the octahedral layers. 

Aluminum migrates into the tetrahedral layers, substituting for Si4 + , which leaves the structure to later form 

quartz. The Mg2+ sites are filled with K+ , which then consolidates the structure from a mixed-layer to an illitic 

phase, the nature of which is a function of the amount of 

potassium present. Weaver and Beck (1971) stated that if
CLAY MINERALOGY 309

this potassium fixation is less than 7 percent, the expanding 

layers will remain in the structure, the main indication of 

which is a broader 10A peak on the X-ray diffraction trace. 

In the framework of the Supai illites, the preceding data 

seem to indicate that the illites have formed in a marine environment, most likely from the upgrading of the random 

mixed-layer clays and (or) weathered, detrital mica. The 

fact that not all clay phases within the marine environment 

have been completely converted to illites, but do exhibit 

various stages of conversion, may suggest that both authigenesis and diagenesis could be operating here. This may 

also be a function of the composition of the original 

phases, for some contained less potassium initially than 

others, and were not able to make the complete conversion 

before marine waters gave way to consolidated sediments. 

The Mg + and K + are mobile ions and the structures are 

variable. With the amount of time (300 m.y.) and an environment potentially close to equilibrium, cation exchange 

is very much to be expected and should be considered as an 

important process in the formation of these clays.

Chlorite clays

Chlorite occurs in the marine rocks of the Supai Group 

intimately with illite. It shares with illite, through geologic 

time, the same associations, abundance in ancient sediments, and tenacity with depth. Various researchers in the 

field, among them Weaver and Pollard (1973), Weaver and 

Beck (1971), Powers (1959, 1957), and Millot (1964), have 

observed empirically the reaction series that Velde and 

Bystrom-Bruzewitz (1972) were able to produce in the 

laboratory: the transformations of a mixed-layer phase 

through less expansive species plus quartz, to minor expansible plus chlorite, to illite plus chlorite plus quartz. (See 

fig. O8.) From Millot's observations this is a typical assemblage in older sedimentary rocks. The chlorite is formed 

either by destabilization of a mixed-layer (illite-smectite) 

phase or of kaolinite (Dunoyer de Segonzac, 1969; Van 

Moort, 1971; Perry and Hower, 1970; and Muffler and 

White, 1969).

The existence of chlorite in a marine environment 

becomes a function of the salinity; with increasing salinity 

the production of chlorite phases from mixed-layer species 

also increases (Powers, 1957). This transformation starts 

as lateral growths of brucite (Mc(OH)2 ) sheets between the 

basal surfaces of the swelling layers of the smectite phases 

present (Griffin, 1962). Chlorite forms in seawater because 

the necessary magnesium is most abundant there. The 

equivalence level concept proposed by Powers (1957) is a 

detailed discussion of the process. As long as the 

[Mg2 + /K+ ] ratio is about 5:1, which usually occurs at shallower depths, the magnesium will be absorbed preferentially into the mixed-layer structure before the 

potassium, where it substitutes for the existing calcium and

sodium. Potassium is also absorbed into the illite phase, 

but at a slower rate. When these ions, Mg2+ and K + , exist 

in equivalent concentrations, then potassium is absorbed 

more rapidly than magnesium. This explains the association of illite (dominant in ancient sediments) and chlorite 

(associated but not primary).

The chlorites of the Supai clay suite are proposed to be 

authigenic when they occur in marine facies. They have 

developed nearly simultaneously with the considered 

authigenic illites by the above processes, which are also illustrated in figure O8, from the detrital, random mixedlayer phases. The dominant occurrence in marine rocks or 

in calcareous marine facies, except for the definitely 

detrital samples that show the effects of transport; the 

close association with the illites; the existence as an accessory phase; and the very fine grain size coupled with 

some well-defined, unaltered crystal habit (fig. O5E)—all 

these factors can be considered supporting evidence for the 

hypothesized authigenic origin of the chlorites in marine 

sediments.

Corrensite

An extensive discussion relative to the origin and occurrence of corrensite or "corrensite-type" clay minerals is in 

the literature. Some of the diverse environmental associations are described by Blatter, Roberson, and Thompson 

(1973). In sedimentary rocks, corrensite is most commonly 

associated with carbonate and evaporite deposits and 

therefore its occurrence is important in the reconstruction 

of the Supai history.

The age, occurrence, mineral associations, and environments of formation of some of the sedimentary corrensites 

documented in the literature are summarized in table O3. 

Several conclusions can be drawn from this information: 

(1) corrensite appears to be stable through long periods 

of geologic time, and is shown by Weaver and Beck (1977, 

p. 216) to have been most abundant during the Paleozoic 

and Mesozoic Eras; (2) carbonates, and especially dolostones, are always associated; (3) evaporite minerals 

are commonly present, but not required; and (4) illite is 

normally present. Although some previous researchers 

(Lippmann, 1956; Grim and others, 1959; Millot, 1964; 

Lucas and Ataman, 1968) have hypothesized that corrensite is restricted to a narrow, hypersaline environment, 

subsequent investigations (Johnson, 1964; Peterson, 1961; 

Almon and others, 1976; Velde, 1977b) suggested broader 

geochemical parameters for its authigenic development.

From the mineral associations shown in table O3, the 

shallow marine conditions of an epicontinental sea seem to 

favor corrensite formation. Localized salinity changes, 

where slightly hypersaline conditions occur as large concentrations of magnesium build up (possibly due to 

calcium precipitation into calcite) in lagoonal settings
310 THE SUPAI GROUP OF GRAND CANYON 

TABLE O3. —Sedimentary corrensite occurrences

Reference

Bradley and Weaver (1956)

Honeyborne (1951) ............

Age

. . . . Triassic ..........

Formation-locality

Colorado.

Buntsandstein, 

Germany. 

. Keuper marl,

England.

Mineral association

(incomplete data). 

Dolomite, calcite,

illite, quartz, hematite, 

halite, gypsum. 

Calcite (dolomite),

illite (gypsum).

En vi ron ment-descri ption

Continental salt lake and

salt flat. 

Hot, semidesert conditions;

warm sea— shales,

Earley and others (1956) ........... Permian

Grim, Droste, and Bradley (1959) ... Permian

Koppand Fallis (1974)............. .......

Almon, Fullerton, and Davies (1976). Late Cretaceous

Peterson (1961, 1962) ............. Late Mississippian

Martin-Vivaldi and MacEwan (1957). . Triassic

Lucas and Ataman (1968) .......... Triassic -

Millot, Lucas, and Wey (1963) ...... Triassic .

Lippman (1976) .................. Triassic

Rao and Bhattacharya (1973) ....... Tertiary

Yates Formation, Texas

Salado Formation, 

New Mexico.

Wellington Formation, 

Kansas, Hutchinson 

Salt Member

Horsethief Formation, 

Montana

Cumberland Plateau, 

Tennessee.

Catalan and jura 

Formation, 

Spain, France.

Jura Basin, France

Muschelkalk Formation, 

Keuper Formation.

Keuper Formation, 

"Gipskeuper."

Sirban Limestone, 

Himalayas, India.

Dolomite, quartz, feldspar, 

mica, organics.

Dolomite, 

evaporite minerals.

Dolomite, gypsum,

anhydrite, quartz

illite or mica. 

Calcite, dolomite ........

Dolomite, calcite, quartz, 

K-spar, albite, illitemica.

Calcite, dolomite, 

quartz, illite.

Gypsum, anhydrite,

halite, dolomite. 

Calcite + (?).

Quartz, mica, illite, 

gypsum, dolomite, 

anhydrite.

Dolomite, clays ...

dolomites, sandstones 

with coal stringers. 

Argillaceous siltstone.

Mildly acidic Mg+2

Na + K + -rich

environment. 

Hypersaline.

Delta distributary channels 

and distributary mouthbar environment.

Carbonate.

Rocks corresponding to 

Keuper muschelkalk, 

Bunter of Germany; 

carbonates, shales, 

muds.

Carbonates, evaporites, 

argillaceous sandstones.

Argillaceous sediments, 

mudstones.

Microdolosparite, limestone 

and shales, some 

hypersalinity.

behind barrier bars. The equivalence level concept of 

Powers (1957) can again be cited in support of shallowwater deposition of corrensite. Magnesium substitution is 

favored at shallow depths.

Corrensite can also exist in restricted, large evaporite 

basins, and it is found in deltaic channels and distributary mouth bars (Almon and others, 1976). These locales 

imply low-energy environments and impounded waters. 

Corrensite seems to equate with a magnesium-enriched 

environment.

The conclusions of Lucas and Ataman (1968) imply that 

corrensite can find stability in a carbonate facies where 

much of the magnesium is related to the dolostones. Too 

little is then left to form a true chlorite but the silica tetrahedra acquire some of the Mg2+ ions to form corrensite.

The fact that corrensite is also found with evaporites is 

probably only a function of whatever amount of silica 

(diatoms, smectite) has managed to infiltrate the sulfatechloride environment and this silica actively competes for 

the magnesium, capturing enough to form corrensite but 

not consistently a sufficient amount to complete all the 

chlorite layers of the structure. A deficiency in aluminum, 

which is relatively insoluble and immobile, may be a further consideration relative to corrensite formation over 

chlorite.

Stability temperature, according to Velde (1977b), appears to be from 100°C to possibly 280°C. Corrensite has 

been synthesized from montmorillonite in a magnesiumenriched solution at temperatures between 300° and 600°C 

by Wyart and Sabatier (1966). The stability field of
CLAY MINERALOGY 311

authigenic corrensite has been calculated by Almon, 

Fullerton, and Davies (1976). The parameters that they 

derived have a pH between 7.5 and 8.8 and a high 

magnesium-calcium ratio. As would be anticipated, the 

stability field of corrensite is somewhat limited, which 

makes it a potentially useful environmental indicator. 

Figure O9, modified from Almon, Fullerton, and Davies 

(1976, fig. 7) illustrates stability fields for corrensite and 

associated minerals. This is also in agreement with the 

work done by Peterson (1961, 1962). It is supported by 

synthesis experiments conducted by DeKimpe, Gastuche, 

and Brindley (1961); by Caillere, Henin, and Esquevin 

(1953); and by Kotov, Lebedev, and Tarlakov (1969).

Some parallels can be drawn from Peterson's (1961, 

1962) work on the carbonate rocks of the Cumberland 

Plateau in Tennessee and the two lower formations of the 

Supai Group. Most of the same mineral assemblages are 

present, although the Supai seems to be more siliceous 

and to contain more detritus in its nearshore carbonate sequence. The dolomite-corrensite, calcite-dolomitecorrensite, and calcite-corrensite mineral assemblages of 

the Cumberland Plateau are recognized and their chemical 

origins can perhaps be equated with similar parts of the 

Watahomigi and the Manakacha. The Supai does not appear to have had as much magnesium because it does not 

contain all the more complex magnesium-bearing minerals 

of the Cumberland rocks. However, the basic authigenic 

mechanisms seem applicable. These mineralogical and 

lithologic assemblages, which seem to satisfy Gibb's phase 

rule, are a definite function of the chemical equilibrium 

established at the time of deposition and so subsequent 

diagenesis is unlikely, according to Peterson (1961, 1962).

The probable authigenic origin of the corrensite in the 

Supai Group is supported by its lithologic associations. It 

occurs throughout the marine facies of the Watahomigi 

and Manakacha Formations, the two showing the least 

energy of the group. Corrensite occurs in the Esplanade, 

but only very selectively associated with the gypsum 

deposits. Figures O12 and O13, the fence diagrams for the 

Watahomigi and Manakacha, show corrensite occurring 

exclusively in the limestones or in siltstones closely associated with limestones, particularly in the nearshore areas 

and in narrow limestone lenses that may have been 

restricted lagoons surrounded by calcareous silt and mud.

The cluster configuration of many corrensite samples 

suggests localized conditions especially favorable to its formation. Calcite, dolomite, quartz, feldspars, and illite are 

associated with corrensite in the Supai rocks. Kaolinite, 

with its implications of an acidic, high-alumina environment has not been found associated with corrensite. No indications of hypersaline conditions occur in the Watahomigi and the Manakacha, but rather a relatively normal 

marine salinity with localized areas of high magnesium 

concentration. Possible magnesium sources would be the

FIGURE O9.—Corrensite stability relationships; modified from Almon, 

Fullerton, and Davies (1976, fig. 7). This diagram implies environmental 

compatability but not necessarily contemporaneous deposition.

evaporation of seawater along a shallow broad shelf near 

shore, degradation of detrital magnesium-bearing 

minerals, and high magnesium-bearing dolostones. The 

corrensite-carrying gypsum rocks of the Esplanade are 

closely associated with dolostones, which would support 

the theory of a magnesium-enriched environment. The 

transitional swelling chlorite-type minerals that occur in 

stratigraphic proximity are additional indicators of the 

authigenic origin of this assemblage.

Kaolinite

Kaolinite is not considered to be a common clay constituent of older rocks. It is destroyed with long periods of 

time. In many places, the nearshore environment, where a 

high volume of probably detrital kaolinite is deposited, has 

been eroded. Another factor against its formation in ancient sediments was unfavorable climatic conditions 

(Weaver, 1957, 1958; Rateev, 1963; Parham, 1966). 

However, the Permian is known to have had periods of 

lateritic weathering that promotes kaolinite formation 

(Weaver, 1957; Weaver and Beck, 1971).

Kaolinite is a primary clay mineral of continental environments. Kaolinite does not form in a marine environment although it is known to exist in transitional marine 

waters as a function of transport from its continental 

origins (Grim and others, 1949; Millot, 1970; Keller, 1970;
312 THE SUPAI GROUP OF GRAND CANYON

FIGURE OIO (above and facing page).—A, Scanning electron microscope photograph of a kaolinite sample which illustrates various criteria for authigenic 

origin. 6, Sketch of photograph indicating examples of criteria; 1, Pseudo-hexagonal plates stacked face to face along the c axis in randomly 

oriented "books"; 2, twinning notches; 3, helical growth patterns; 4, serrated edges.

Weaver and Pollard, 1973); however, it is considered to be 

unstable in seawater (Rex and Martin, 1966).

Where kaolinite is present as a dominant phase, there is 

usually no other clay mineral in the rock. This relationship 

could support the authigenic premise as the formation of 

kaolinite requires leaching of cations needed for other claymineral formation, unless those other clays are detrital. If 

the Supai kaolinite has a detrital origin, it would probably 

be found in more abundance with clay minerals that have 

not been leached, but it is not. Most associated illite is 

degraded, indicating again a possible leaching environment. The nonassociation of corrensite and kaolinite substantiates the authigenesis of both as they form in mutually 

incompatible environments.

The general consensus of the authors just cited and of 

numerous others is that kaolinite forms in an acidic, oxidizing environment—one where intensive leaching of an 

aluminum-silicate parent rock is occurring. Potassium, 

sodium, calcium, magnesium, and iron must be removed 

with the addition of the hydrogen ion to create this nearly 

pure aluminum-silicate (AlzSizOsiOHJJ.This process implies permeable rock or soil with a sloping drainage, 

greater precipitation than evaporation with a pH of equal 

to or less than 7.0 (according to the stability diagram of 

Garrels and Christ, 1965), and a high aluminum to silica 

ratio. Removing especially the magnesium will keep the 

silica in solution and mobile as this ion will enhance silica 

precipitation. Potassium and sodium feldspars from 

granitic rocks would probably lose silica faster with subsequent aluminum enrichment than would the more mafic 

calcium-magnesium rocks (Keller, 1964). The hydrogen 

ion is added from decomposed organics in the percolating
CLAY MINERALOGY 313

B

ground water. If the potassium is not efficiently removed, 

then a lower pH (4.5) is required for kaolinite formation 

(Keller, 1970). Seawater usually contains sufficient 

potassium so that illitic phases are preferentially formed 

over kaolinite in a marine environment (Keller, 1970). 

Conversely, detrital kaolinite introduced into marine 

waters may combine with K+ and evolve toward an illite 

(Grim and others, 1949; Kulbicki and Millot, 1963). 

Theoretically, kaolinite could be created in a potassiumdeficient marine environment. However, that would be a 

very rare situation. This K+ preference is one reason for the 

use of the presence of kaolinite in a rock as a demarcation 

line between marine and continental facies, as even detrital 

kaolinite is usually not transported very far into the 

marine environment, but flocculates and settles out upon 

contact with saline waters (Keller, 1970; Grim and others, 

1949; Dunoyer de Segonzac, 1969; Parham, 1966). 

The stability range of kaolinite relative to temperature is 

highly variable. Data compiled by Dunoyer de Segonzac

(1969) indicate stability to 190°C. However, the properly 

constituted circulating geochemical solutions can destroy 

kaolinite at 80°C. The phase diagrams of Garrels and 

Christ (1965) were drawn for 25°C. Velde (1977a) synthesized kaolinite at 300°C. It is stable in seawater to 100°C, 

according to work done by Hemley (1959). The majority 

of the data would indicate a low stability temperature, one 

compatible with sedimentary processes, and one that suggests shallow burial.

In the interpretation of the origins of the Supai Group, 

kaolinite will be treated as an authigenic clay mineral 

formed in a continental environment. This conclusion is 

based on mineralogic, petrographic, lithologic, and paleogeographic criteria.

The SEM photograph shown in figure OlO is an exceptionally good illustration of various mineralogic, authigenic parameters. The kaolinite appears to consist of welldeveloped, pseudo-hexagonal plates stacked face to face 

along the c axis. These "books" are randomly oriented
314 THE SUPAI GROUP OF GRAND CANYON

relative to each other (Wilson and Pittman, 1977). Some of 

the flakes and books show grooves or notches, which according to Mansfield and Bailey (1972) may be indicators 

of twinning. Additional criteria include helical growth patterns and serrated edges listed by Bohor and Hughes 

(1971). ED AX spectra for the sample shown in figure O10 

indicate high silica and aluminum with minor potassium 

and calcium.

Petrographic evidence for a possible authigenic origin is 

shown in figure Oil, which is a photomicrograph of a 

potassium feldspar grain being altered to kaolinite.

From figure O6, it becomes apparent that kaolinite in 

the Supai favors rocks of continental origins. Among the 

proposed authigenic clay species present, kaolinite is the 

dominant clay in the sandstones, siltstones, mudstones, 

and conglomerates—the most permeable and therefore 

most leached rock types. Its minor associations with carbonate rocks can be accounted for by local sand, silt, and 

mud facies within limestones and dolostones, and by transport as detritus into the fringes of the sea. Paleogeographically, kaolinite is almost exclusively confined to continental facies and is therefore useful in delineating marine from 

continental environments. Kaolinite is best developed in 

the Esplanade Sandstone (fig. O15) and in the Manakacha 

Formation (fig. O13), and is consistently present in the 

Wescogame Formation (O14). The distribution of kaolinite 

in the Watahomigi Formation (fig. O12) best demonstrates 

its nonassociation with corrensite.

The above criteria can, admittedly, also be convincingly 

applied to a diagenetic origin for this clay species. Whether 

kaolinite was formed at the time of the deposition of the 

Supai or during subsequent eons cannot unquestionably be 

determined; however, the mineral was formed in place, it 

was not transported from an outside source, and as such is 

a valid indicator of continental facies.

GEOGRAPHIC DISTRIBUTION 

AND POSSIBLE RELATION TO 

DEPOSITIONAL 

ENVIRONMENT

The generalized paleoenvironment of a facies can be 

briefly sketched from the distribution of the authigenic 

clays and possibly also from some of the diagenetic clay 

species contained in the rocks. With only limited exceptions, the hypothesized authigenic clay minerals of the 

Supai occur in compatible lithologies. Kaolinite seems to 

be most abundant in the muds, sands, and silts of continental environments. Illite and most of the chlorite occur 

in the marine carbonate rocks. Corrensite occurs in the 

more restricted nearshore carbonate and calcareous mud

FIGURE OH.—Photomicrograph of a potassium feldspar grain being 

altered to kaolinite.

facies and is also associated with the gypsum facies. 

However, the random mixed-layer (illite smectite) phases 

and the mixed-layer (illite-smectite) clays appear in all 

the rock types, which suggests either a more complex 

history of development or a detrital origin, and possibly 

both.

A general trend occurs with the random mixed-layers for 

the illite phase to dominate or to show better development 

in the more extensive marine lithologies to the west, 

whereas the structure of the eastern clays is less ordered 

and the peak definition is poorer. This determination commonly is very subtle and the differentiation with depth 

does not seem everywhere to prevail.

In figures O16 and O19, each formation of the Supai 

Group has been divided into the topographically defined 

slope and cliff units. Clay minerals in each unit have been 

summarized and plotted on a map of the Grand Canyon 

area.

Figures O12-O15 show rock types and associated clay 

minerals in three-dimensional color fence diagrams.

Each formation in the Supai Group will be individually 

discussed in the following sections relative to the clay 

types present, their geographic and lithologic distribution, and their possible relationships to the depositional 

environment.

Watahomigi Formation

Figure OI6A shows the lateral distribution of clay 

minerals in the lower slope unit of the Watahomigi. The illites, chlorites, and corrensites are evidence that a marine 

environment prevailed in the western half of the area 

during Morrowan time. There may have been a shallow,
CLAY MINERALOGY 315

warm, quiet sea with impounded—but not hypersaline— 

evaporite basins, lagoons, ponds, or restricted embayments. Water bodies were cut off from freshening influxes 

sufficiently to concentrate the seawater with some salts.

The occurrence of corrensite as far east as Grandview 

Trail section (no. 6), and of illite directly to the north along 

Kaibab Trail, north, section (no. 8), but with kaolinites 

between, suggests that part of the sea extended far 

eastward. The sea possibly ended or was restricted at the 

Grandview area, allowing the corrensite to form. The intermittent distribution of continental type clay (kaolinite) 

and marine clays (illite, chlorite, corrensite) indicate that 

the facies intertongue and that a transitional land-sea interface existed in this area. The kaolinite may delineate a 

delta.

The random mixed-layer clays of central and western 

Grand Canyon (fig. Ol6) show a dominantly illitic 

character. These clays were subjected to seawater for a sufficiently long time to fix the requisite potassium that 

upgrades their structure toward a marine illite. The somewhat incongruous combination of kaolinite, chlorite, 

montmorillonite, and random mixed-layer clay at Marble 

Canyon section (no. 3) and at Twentynine Mile Canyon 

section (no. 2) are probably the result of detrital clays in 

the conglomerate. The chlorite may result from an 

isolated, marginal, marine pool.

O166 shows that the upper slope unit has a distribution 

of clay minerals similar to that of the lower slope. The 

sample distribution, however, is not as well placed for purposes of interpretation as is that of the lower slope. The 

main sea boundary was about the same. Silt and mud may 

have advanced farther west; at least, there is less evidence 

of a continuous sea embayment extending eastward. The 

isolated illite at Fishtail Canyon section (no. 12) is probably comparable to the chlorite at Twentynine Mile Canyon, for both seem to record a small marine embayment.

The general impression of the Watahomigi environment is 

that it consisted of quiet water, transitional marine embayments with fluctuating water levels, some of which became 

restricted and were cut off from freshening waters, possibly 

a river forming a delta with many tributaries that migrated 

across tidal flats to the open sea. The types of clay present 

and their distribution suggest such an interpretation.

Manakacha Formation

The clay mineralogy shows that in some respects the 

Manakacha environment was similar to that of the Watahomigi, but in others quite different. The land-sea interface 

is more clearly defined in the Manakacha because of less 

intertonguing of marine and continental facies (fig. O13). 

The greater amount of marine clays such as illite, chlorite, 

and corrensite (figs. Ol6A, B and O17) also indicates the 

continuing and dominant role of the saltwater facies in the

Manakacha. The clays show a less scattered pattern in 

their geographic distribution (figs. O16 and Ol3). In the 

northeast part of the Grand Canyon region, a marine environment persisted. Illite is abundant, and at Andrus Canyon section (no. 24) it is the only clay detected in the section. As 80 percent of the illite samples that occur in this 

formation are associated with limestone (fig. O18), an 

authigenic origin of the illite seems probable.

The common occurrence of corrensite, especially as 

represented in Toroweap Valley section (no. 21) and in 

Separation Canyon section (no. 34) seems to indicate, as in 

the Watahomigi, that at least those parts of the sea were 

quiet areas of low energy. Corrensite development continued in the Separation Canyon area throughout the time 

of carbonate and argillaceous mud deposition, suggesting 

that this area was possibly impounded for an appreciable 

length of time. Blue Mountain Canyon section (no. 19), 

directly east of Separation Canyon, also contains corrensite in a fairly thick limestone unit, substantiating the idea 

of a large, quiet, marine lagoon in that area. Although 

most of the corrensite occurs associated with limestone as 

figures Ol8 and O13 show, corrensite also occurs with 

calcareous silts in proximity to the carbonate rocks (figs. 

O18 and O13). Corrensite does not occur in the 

Manakacha east of National Canyon section (no. 15) and 

Tuckup Canyon section (no. 18), nor does it occur anywhere in proximity to the sand facies of this formation. As 

in the Watahomigi, the presence of corrensite appears to be 

useful as an indicator of depositional environment.

The random mixed-layer clays, when found in the carbonate, marine facies of the west, tend to favor the 10A or 

illite phase of their development. This situation suggests a 

marine environment where potassium fixation was 

possibly upgrading less-ordered clays toward illite. Otherwise, the random mixed-layer clays do not show any 

useful distribution patterns relative to paleoenvironmental 

interpretations.

The Manakacha has more definite boundaries than does 

the Watahomigi between sea and land as indicated by the 

distribution of the authigenic clay types in the formation. 

Figure O13 seems to be a more realistic representation of 

the general configuration of the clay minerals in the Manakacha than does figure O16, in which time planes are lacking. A close examination of the illite associated with continental sediments at measured sections 2, 8, 9, and 6 shows 

that these illites are probably degraded, detrital micas and 

therefore not very useful as depositional environmental 

indicators.

The chlorite is also probably detrital; its occurrence is 

ubiquitous. There are too few chlorite samples to speculate 

on their origin.

Toward the east, Manakacha marine deposits grade into 

continental facies, which are probably delimited by the 

distribution of the kaolinite. Kaolinite is found mostly east
9ie 3H1 IVdHS D dHOtf JO ClNVtfD NOANVD 
SECTIONS SOUTH OF 

GRAND CANYON

EXPLANATION

Projection 

enhancement

0 

20 MILES

FIGURE O1 2. —Distribution of clay minerals relative to lithologic facies within the Watahomigi Formation of the Supai Group, Grand Canyon, Ariz. Numbers are those of measured

sections (fig. AT).
3H1 IVdQS dHO^ID dO CINVtfD NOANVD 
SECTIONS SOUTH OF 

GRAND CANYON

19

Muddy siltstone

SandstoneLimestone

Dolostone

Conglomerate

EXPLANATION

CLAY SPECIES 

^ Random mixed-layer 

v Illite

• Kaolinite 

n Mixed layer

• Chlorite ° Smectite

• Corrensite

Projection 

enhancement

FEET 

-150-100- 50

0

20 MILES

FIGURE O13.— Distribution of clay minerals relative to lithologic fades within the Manakacha Formation of the Supai Group, Grand Canyon Ariz. Numbers are those of measured

sections (fig. A1).
oze HHI IVdflS dflOHD JO QNVHD NOANV3 
SECTIONS SOUTH OF 

GRAND CANYON

EXPLANATION

	CLAY SPECIES

• Random mixed-layer

v Illite

• Kaolinite

D Mixed layer

• Chlorite° Smectite

Muddy siltstone

Sandstone

LimestoneDolostone

Conglomerate

0 

20 MILES

n

Projection 

enhancement

FIGURE O14. —Distribution of the clay minerals relative to lithologic fades within the Wescogame Formation of the Supai Group, Grand Canyon, Ariz. Numbers are those of

measured sections (fig. A1).

N)
SECTIONS NORTH OF 

GRAND CANYON

8
SECTIONS SOUTH OF 

GRAND CANYON

EXPLANATION

CLAY SPECIES 

T Random mixed-layer 

v lllite

• Kaolinite 

D Mixed layer• Chlorite 

Corrensite

FEET 

n 150 Muddy siltstone 

SandstoneDolomitic limestone 

Dolomitic sandstone 

Gypsum 

Dolostone (Pakoon) 

Conglomerate

FIGURE O15.— Distribution of clay minerals relative to lithologic facies 

within the Esplanade Sandstone (includes tongues of Pakoon Limestone of McNair (1951) in western part) of the Supai Group, Grand Canyon, Ariz. Numbers are those of measured sections (fig. A1). OJ
324 THE SUPAI GROUP OF GRAND CANYON

B

CLAY SPECIES 

AMOUNT TYPE 

Major Minor

T T Random mixed-layer 

v v Illite 

D D Kaolinite

• • Mixed layer

• • Chlorite 

o ° Smectite

• * Corrensite

FIGURE O16.—Horizontal distribution of clay minerals within the Watahomigi and Manakdcha Formations of the Supai Group, Grand Canyon, 

Ariz. A, Lower slope unit, Watahomigi; 8, upper slope unit, Watahomigi; C, cliff unit, Manakacha; D, slope unit, Manakacha. Numbered 

dots are localities of measured sections (fig. A1).

of Fishtail Canyon section (no. 12) on the north and Hava- WeSCOgame Formation

su Canyon section (no. 14) on the south. Its occurrence is 

sharply defined and should be an indicator of the transition zone between marine and freshwater environments. 

The kaolinite distribution pattern is clearly shown on both 

the vertical (fig. O13) and horizontal (fig. O16) illustrations. Kaolinite appears to slightly favor the silts and muds 

over the sands (fig. O18). The broad vertical distribution 

(fig. O16) of the kaolinite strongly suggests the terminus of 

a river delta outlining zones where a delta meets the sea 

and freshwater mixes with seawater. The authigenic origin 

of this clay is suggested by its restriction primarily to the 

continental facies of the Manakacha.

The Wescogame Formation has not been as thoroughly 

analyzed for clays as have the other three formations of 

the Supai Group. Speculations about the paleoenvironment of the Wescogame are not, therefore, as completely 

supported as are those of the other units.

Relatively few carbonate rocks occur in the Wescogame 

and, probably for this reason, little authigenic illite is present. The illite, with only a couple of exceptions that are 

probably of detrital origin, occurs in the limestone (fig. 

O18). Some of the illite is accompanied by chlorite.

In the Wescogame, marine clays are largely restricted to
CLAY MINERALOGY 325

CO

120

110

100

90

80

70

60

50

40

30

20

10

0

100

90

80

70

60

50

40

30

20

10

0

ESPLANADE SANDSTONE 

(202 samples)

RML K I Chl Corr ML

100

90 

80

70

60

50

40

30

20

10 

0

-

WESCOGAME FORMATION 

(92 samples)

-

-

-

-

-

-

m

i|

I!IS

til

i! 0 m

RML K I Chl Corr S ML

MANAKACHA FORMATION 

(183 samples)

RML K I Chl Corr ML

100

90

80

70

60

50

40

30

20

10

0

WATAHOMIGI FORMATION 

(189 samples)

RML K I Chl Corr ML

CLAY TYPE

FIGURE O17.—Distribution of clay minerals by numerical count within each formation of the Supai Group, 

Grand Canyon, Ariz. Esplanade Sandstone includes tongues of Pakoon Limestone (McNair, 1951) in 

western Grand Canyon. Clay types are: RML, random mixed-layer; K, kaolinite; I, illite; Chl; chlorite; 

Corr, corrensite; S, smectite; ML, mixed-layer.

the far western part of the area (fig. O14). Illite occurrences to the east of Andrus Canyon section (no. 24) on the 

north side of the embayment, are confined to small areas 

that seem to have developed in lagoons, cut off from the 

sea by great sand bodies. One probable small lagoon, 

centered near Kaibab Trail, north, section (no. 8), may 

have had minor amounts of corrensite associated with the 

illite. The sample is poorly defined, but such a restricted 

marine environment might have been favorable for corrensite production. On the south side of the embayment, 

deposits in one slender arm of the sea that extended landward contain some illite, considered to be of marine origin. 

Chlorite in the Wescogame may be mostly detrital. 

Figure O17 shows only five chlorite-bearing samples. Two 

of these were in marine associations with illite; the others 

were in sands and silts. Therefore, chlorite in this formation does not seem to be very useful in reconstructing the 

paleoenvironment.

Kaolinite in the Wescogame (fig. O17), as in the other 

formations, is the second most abundant clay mineral. It 

occurs exclusively among sandstones and siltstones (fig. 

O18) and, therefore, is restricted to the eastern two-thirds 

of the Grand Canyon area. It is mostly in sandstones and 

those conglomerates with less than 15 percent of the analyzed samples of silt size. However, this may be somewhat 

misleading as less silts than sands were analyzed, and less 

samples in general were analyzed in this formation. The 

existence of kaolinite within the sandstone suggests that it 

contains or contained sufficient feldspar to produce the 

kaolinite and that it was permeable enough to allow 

leaching waters to percolate freely throughout.

The random mixed-layer clays, like the kaolinites, are 

commonly associated with the sandstones and very few occur in the carbonate rocks. The depositional environment 

in which these potentially detrital clays accumulated 

possibly was shallow water and nearshore, and their agent
326 THE SUPAI GROUP OF GRAND CANYON

ESPLANADE SANDSTONE

RML

0 0 00

Corr

70

60

50

40

30

20

10

ML

MANAKACHA FORMATION

Corr ML

RML

WESCOGAME 

FORMATION

1

i

si in

ii

i| 

11

; 3

: 1

/\j 

60

50

40

30

20

10

ft

Sandstone 1

ML RML 

CLAY TYPE 

EXPLANATION

WATAHOMIGI FORMATION

Corr

Siltstone Mud stone Carbonate rock LJ No samples in that rock type

FIGURE O18.—Percentage of distribution of clay minerals within each formation of the Supai Group and relative to rock type. Esplanade Sandstone includes of Pakoon Limestone (McNair, 1951) in western Grand Canyon. RML, random mixed-layer clays; K, kaolinite; I, illite; Chl, chlorite; Corr, 

corrensite; S, smectite; ML, mixed-layer clays.

of transport did not seem able to carry them far from the 

shoreline.

With the limited number of samples available from the 

Wescogame, the paleoenvironment cannot be reconstructed in any detail. Illite deposits shown in figure O14 

probably represent the locations of isolated lagoons and 

the illite-kaolinite interface in figure O14. Although the sea 

again covered extensive areas during Wescogame deposition, the small number of marine clays (fig. O17) indicates 

that it was considerably smaller than during deposition of 

the Manakacha and Watahomigi. A continental environment was increasingly more widespread in the region than 

before.

Esplanade Sandstone and 

Pakoon Limestone

The Esplanade Sandstone is very different from the 

other three formations in the Supai Group. Figures O15 

and O18 indicate mostly continental facies. Figure O17 

further illustrates this relationship by pointing out the 

dominance of continental clay types. In western Grand 

Canyon, tongues of the Pakoon Limestone (McNair, 1951) 

replace the lower part of the Esplanade. These tongues are 

predominantly dolostone, indicating a restricted marine 

environment.
CLAY MINERALOGY 327

CLAY SPECIES 

AMOUNT TYPE 

Major Minor

v T Random mixed-layer 

v v Illite 

n D Kaolinite

• • Mixed layer

• • Chlorite 

o o Smectite

• * Corrensite

FIGURE O19.—Horizontal distribution of clay minerals within the Wescogame Formation and Esplanade Sandstone of the Supai Group, Grand 

Canyon, Ariz. A, Cliff unit, Wescogame; 8, slope unit, Wescogame; C, main cliff unit, Esplanade; D, slope unit, Esplanade (includes tongues 

of Pakoon Limestone of McNair, 1951, in western Grand Canyon). Numbered dots are localities of measured sections (fig. A1).

The small amount of illite occurring in this interval (fig. 

O17) is associated predominantly with carbonate Pakoon 

tongues (fig. O18). Authigenic illites are in dolostones of 

the Pakoon of Hidden Canyon (no. 30) and Iceberg Canyon (no. 31) measured sections in the far west. Also the illites are associated with the Esplanade gypsum beds of Andrus Canyon section (no. 24). In brief, all illites occur west 

of Toroweap Valley section (no. 21) (figs. Ol5 and O19). 

Although figure O15 seems to indicate that the illite is 

associated with sandstones, it actually occurs in calcareous 

and dolomitic lenses within the sandstones. Samples identified as illite from the siltstones in figure O18 likewise are

probably not authigenic illite but detrital, degraded micas. 

This distribution pattern seems to put a strictly marine environment (Pakoon) largely beyond the area of study, and 

the only marinelike facies are those of restricted, quiet 

waters of evaporitic chemical-precipitate basins and embayments that extend from these basins into continental 

facies of the Esplanade Sandstone.

Andrus Canyon section (no. 24) contains sparse deposits 

of corrensite in a gypsum facies of the cliff-slope unit of 

the Esplanade. This is compatible with the magnesiumenriched environment of the evaporite basin of gypsum 

deposition.
328 THE SUPAI GROUP OF GRAND CANYON

Chlorite is more common than illite in the Esplanade 

Sandstone (fig. O17). Its distribution (fig. O18) is chiefly in 

sandstone, siltstone, and mud rocks believed to be continental. It is associated with both random mixed-layer and 

kaolinite clay types, but not with illite (fig. O15). Chlorite 

is confined to the cliff-slope unit of the Esplanade (fig.

019) and no definitive pattern is recognized in its lateral 

distribution. These data seem to indicate that chlorite of 

the Esplanade may be detrital in origin.

Aside from random mixed-layer clays, kaolinite is the 

most abundant clay mineral of the Esplanade (fig. O17). It 

occurs primarily in the sandstones, less than 25 percent is 

in mudstone and siltstone, and about 1 percent is in carbonate rocks (fig. O18). On the north side of the Grand 

Canyon, kaolinite occurs throughout the region, but it is 

most abundant east of Andrus Canyon section (no. 24). 

Kaolinite occurs primarily in the sandstone facies; it is 

associated with random mixed-layer clays and, notably at 

Andrus Canyon, has probable detrital chlorite also associated with it. To the south, except for a single sample in a 

conglomerate at Blue Mountain Canyon section (no. 19), 

kaolinite is found only east of Prospect Valley section (no.

20). Nearly all samples are associated with sandstones, two 

exceptions being in siltstone. Chlorite associated with 

kaolinite has been found only at Hermit Trail section (no. 

9), on the south side of Grand Canyon.

The abundance of kaolinite in the Esplanade Sandstone 

assists in reconstruction of the history of this formation. 

Very little kaolinite is found to the west of measured sections 20 and 24 (Prospect Valley and Andrus Canyon), so 

these sections mark the easternmost extent of the marine 

facies and the presence of kaolinite is considered as an indicator of the continental-marine interface. Kaolinite implies 

an oxidizing environment with associated Fe2O3 (as hematite) as evidence. Most of the samples examined contain 

accessory hematite. The feldspar-bearing, more continental rocks, especially those with potassium feldspar, apparently favored kaolinite formation. The sands must have 

been well drained and had moderate to high permeability 

for the kaolinite to form. The environment must have been 

acidic or well leached because the cations were efficiently 

removed and bordering areas of moderate relief may have 

helped accelerate the leaching processes. Because this clay 

mineral does not form in areas of enrichment and poor 

drainage, the kaolinite probably did not concentrate in 

basins.

The Esplanade Sandstone of the Grand Canyon consists 

mostly of continental sediments. The lower part of the 

Esplanade in western Grand Canyon is replaced by marine 

dolostone of the Pakoon. Later, the aridity was such that 

gypsum formed in the upper part of the Esplanade Sandstone. A small source area to the south may have provided 

the limited amount of detrital chlorite present in some sections of eastern Grand Canyon (Kaibab Trail, north, measured section 8, and Hermit irail, measured section 9). 

Most of the Esplanade seems to have been laid down in an 

oxidizing environment, probably warm and fairly dry, but 

with sufficient drainage to decompose the feldspars and to 

cany away the leached material.

SUMMARY

Considering the interrelationships illustrated in figure 

O8 and integrating these with the paleogeographical ones 

of figures O12-O15, some of the transformations suggested by Lucas and Ataman (1968), Millot, Lucas, and 

Wey (1963), and ably summarized by Dunoyer de Segonzac (1969) seem to find reaffirmation in the Supai Group. 

These theories of authigenic formation, of aggradation 

from preexisting detrital materials and unstable clay 

phases seem to offer the simplest explanation for the 

origins of the Supai clays.

The abundance of random mixed-layer clays in various 

stages throughout the Supai would seem to illustrate that 

the aggradation processes of Lucas and Ataman (1968), 

among others, were in operation on the detrital, degraded, 

and micaceous materials, which were obviously abundant 

throughout the Supai. In the marine environment these are 

upgraded through random mixed-layers to illites or corrensites to chlorites, depending on the available plentiful 

cation. In the continental environment with minor circulating waters, the aggradation processes have been considerably less rapid, resulting in only a random mixedlayer configuration; at least some of the kaolinite has been 

created through feldspar weathering.

The marine environment seems to have been more active 

than the continental relative to clay authigenesis. The presence of the somewhat rare mineral corrensite has been of 

great assistance in the reconstruction of possible depositional conditions, because its stability field and preferred 

environment are fairly limited and can be defined to some 

degree.

In general, the hypothesized authigenic clays—illite, 

chlorite, corrensite, and kaolinite—favor compatible relationships among themselves relative to the rocks within 

which they occur, and with other environmental data presented within other chapters of the present Professional 

Paper. Therefore, they are considered as valid indicators 

of original depositional environments within the various 

formations. The Watahomigi Formation, with its preponderance of marine clays, especially corrensite, is interpreted to be a result of a quiet marine and transitional 

marine environment with emphasis on restricted, lowenergy conditions. The Manakacha was probably also 

largely marine with its illite, chlorite, and corrensite clays 

prominent to the west. However, a definite continental 

environment also is present in the Manakacha and is
CLAY MINERALOGY 329

delineated by the kaolinite distribution pattern. With the 

Wescogame, continental facies start to dominate in the 

embayment. Finally, a progression from marine to continental is completed, as shown by the continental kaolinite 

of the Esplanade Sandstone. In this formation, the continental clays far outnumber the marine species. Even 

though the dominant clay type—random mixed-layer 

(illite-smectite)—of the Supai Group is probably a detrital 

interloper, even this phase has been significantly altered 

with time. There are still sufficient authigenic phases to reconstruct, admittedly in a generalized way, a concept of 

the depositional environments 300 million years in the 

past.

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330 THE SUPAI GROUP OF GRAND CANYON

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CLAY MINERALOGY 331

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THE SUPAI GROUP OF GRAND CANYON

PETROGRAPHY OF THE SUPAI

GROUP AND PAKOON

LIMESTONE

Chapter P 

By EDWIN D. McKEE and WALTER PIERCE

Contents

Page

Carbonate rock classification ......... .. ................................................ 335

Basis of investigation .................................................................. 335

Terminology for grain types ..... .... .... ...................................... 335

Terminology for rock fabric ................................................ ....... 336

Classification for mixed sandstone-carbonate rock types ..... .................................. 336

Principal facies of the Supai Group .................................... .... .............. 338

Distribution of the principal carbonate facies in the Supai Group .................................. 338

Facies of the Watahomigi Formation ...................................... ..... ....... 340

Stratigraphic relations of facies .. ................................................... 340

Facies C—Aphanitic limestone ........................................... ... 341

Characteristics ................................................................. 341

Grain types ................................... .... ........................ 344

Grain sizes ..................................................................... 344

Depositional textures and fabrics ......................... .. ................. 344

Mineralogy .... .. ............................................................ 344

Diagenetic modifications .......... ............................................. 345

Interpretation of environment .............................................. .... 345

Facies F—Accretal (algal-foraminiferal) limestone . . .................................... 345

Characteristics ........................................................... . . 345

Grain types ................................................................... 345

Grain sizes ................................................. ................. 346

Depositional textures and fabrics .................................................... 346

Diagenetic modifications ........................................ .............. 346

Interpretation of environment .. .... ............................................. 346

Facies G—Mixed-grain limestone ......................................... ...... 347

Characteristics ................................................................. 347

Grain types ........................................ .......................... 347

Grain sizes ..................................................................... 347

Depositional textures and fabrics ........................ .......................... 347

Mineralogy .................................................................. 347

Diagenetic modifications of fabric .................................................. 348

333
334 THE SUPAI GROUP OF GRAND CANYON

	Page

Facies of the Watahomigi Formation-Continued

Facies H—Coarsely crystalline dolostone .. ............................................ 348

Characteristics ................................................................. 348

Texture and fabrics ...................... .. .............. 348

Interpretation of genesis .......................................................... 348

Facies of the Manakacha Formation .......... ....................... 348

Stratigraphic relations of facies ......................................................... 348

Conventional facies—Stratigraphic relations ........................... .. ..... 350

Facies A—Red argillaceous mudstone .................................................... 350

Facies B—Peloidal, calcareous to very calcareous sandstone ..... .............. 351

Facies D—Sandy to very sandy peloidal limestone ......................................... 351

Facies E—Bioclastic limestone .............. ... ........................ 351

Alternative facies classification . ................................................... 351

Facies B' D', alternative ..... ....................................................... 352

Interpretation of facies .... ......... ................................. ....... 352

Facies of the Wescogame Formation ......................................................... 352

Stratigraphic relations of facies ............ ............ .................... ....... 352

Characteristics of facies ................................................................ 354

Facies of the Esplanade Sandstone and Pakoon Limestone . . ................................. 355

Stratigraphic relations of facies .......................................................... 355

Facies A—Red argillaceous mudstone .. ..................... ..................... 355

Facies B—Peloidal cross-stratified sandstone ........................................... 357

Facies E-H—Bioclastic limestone and calcitic dolostone ............................. 357

Facies I—Dolomitic sandstone .......................................................... 357

Facies J—Bedded gypsum .............................................................. 358

References cited ......................................................................... 359

Illustrations

Page

FIGURE PI. Maps of distribution of thin sections showing facies of Supai Group and Pakoon

Limestone ............................................................ . 336

P2. Maps of distribution of thin sections showing rock fabrics of Supai Group and Pakoon

Limestone .......... ....... ... ..... ............ ....... . . . 337

P3. Photomicrographs of rocks of principal facies of Supai Group and Pakoon Limestone ..... 339

P4. Maps showing areal distribution of principal types of clasts of Supai Group and Pakoon

Limestone .............. ....... ...... ......................... 340

P5. Maps showing areal distribution of carbonate mudstone (micrite) and clastic limestone

of Supai Group and Pakoon Limestone ......................... .............. 341

P6. Color fence diagrams of facies of the Watahomigi Formation . ............... 342

P7. Photomicrographs of rocks of facies in the Watahomigi Formation .... 343

P8. Color fence diagrams of facies of the Manakacha Formation .... ......... ....... 349

P9. Photomicrographs of rocks from principal facies of the Manakacha Formation . 350 

P10. Color fence diagrams of facies of the Wescogame Formation ......................... 353

P11. Photomicrographs of rocks from principal facies in the Wescogame Formation ........ 354

PI2. Color fence diagrams of rocks from facies of the Esplanade Sandstone and Pakoon

Limestone ........................................ ................ . . . 356

Pi 3. Photomicrographs of rocks from facies of the Esplanade Sandstone and Pakoon

Limestone ................................................................ 358

Tables

Page

TABLE PI. Terminology for carbonate rocks .... ................................. . . . 335

P2. Terminology for mixed sandstone-carbonate rock .................................. 337
PETROGRAPHY 335

CARBONATE ROCK 

CLASSIFICATION

Basis of investigation

The collection of samples used in this investigation includes specimens, considered representative, from nearly 

all rock units of the Supai Group1 as recognized in 32 

measured section descriptions, and illustrated in figures 

A2-A8. These specimens were selected and documented 

during field studies by McKee and various assistants, spanning a period of more than a dozen years. Petrographic 

analysis of thin sections was by Walter Pierce who contributed much important information based on his systematic 

examinations.

Based on the examination of nearly 1,000 specimens in 

thin section, a twofold classification of microfacies considered both practical and meaningful, has been adopted 

for use in describing carbonate rocks of the Supai Group. 

This classification (table Pi) recognizes (1) three categories 

of limestone based on grain type, and (2) three categories 

based on amounts of carbonate mud matrix, following 

Dunham (1962, table 1). An additional class of limestone 

consists of carbonate mudstone (micrite), with both laminated and nonlaminated varieties. Recrystallized carbonate rock occurs as dolostone and as crystalline 

limestone.

Terminology for grain types

The principal grain types recognized in carbonate rocks 

of the Supai Group are (1) bioclastic, (2) accretal, and (3) 

peloidal (fig. Pi).

Bioclastic grains, referred to as skeletal by some geologists, commonly are easy to identify for they consist of the

1The Pakoon Limestone (McNair, 1951) is included with the Supai Group for the purposes of 

this discussion as it intertongues with the lower part of the Esplanade Sandstone in western Grand 

Canyon.

shells or tests of various marine invertebrate animals. 

Mostly they are fragments that are comminuted or worn, 

but some, especially small varieties, may be unbroken and 

fresh. Animals most commonly represented are brachiopods, mollusks, pelmatozoans (crinoids, echinoids), bryozoans, foraminifers, and ostracodes; they may or may not 

be preserved in recognizable form.

Accretal grains consist primarily of those particles 

formed through the buildup of concentric layers of calcium 

carbonate as in ooids, oncolites, and pisolites, and they 

are mostly spheroidal. Within the Supai Group the most 

common accretal grains are those formed by algal and 

foraminiferal encrustations in various proportions. Unfortunately, the biogenic origin of these accretal grains is difficult to determine from hand specimens in the field, and 

many strata referred to as oolitic (for example, McNair, 

1951) may have been of this type. Algal-foraminiferal accretal grains are prominent in the Watahomigi and lower 

part of the Manakacha. True ooids are uncommon in the 

Supai Group, but locally occur as scattered grains seen in 

thin sections or, rarely, as small concentrations. Pisolites 

are also rare in the Supai Group. Isolated examples come 

from various horizons and localities.

Peloidal grains as originally defined (McKee and 

Gutschick, 1969, p. 101) are largely rounded and ovoid, 

but highly variable in size and shape. Most of them are 

believed to have been derived through erosion of carbonate mud deposits accumulated nearby. Some peloidal 

grains may have formed as fecal pellets and others through 

diagenesis of bioclasts, ooids, or other varieties of grains.

Peloids of the Supai Group probably are polygenetic. In 

the Watahomigi Formation, the presence of two definite 

size groups may indicate that the smaller clasts represent 

fecal pellets. In the Manakacha, however, a consistently 

even size of peloids, similar to that of associated detrital 

quartz grains, probably is the result of derivation from 

deposits of carbonate mud, followed by transportation 

with consequent rounding and sorting of grains.

TABLE PL—Terminology for carbonate rocks

[Modified tram Dunham, 1962]

Depositional fabric Recrystallized fabric

Name ..... Grainstone Packstone Wackestone Carbonate Crystalline Crystalline

mudstone (micrite) dolostone limestone

Amount ....... Grain-supported, Grain-supported, Matrix-supported,

of mud lacks carbonate contains "floating" grains,

matrix mud. carbonate mud.

None.

Grain 

types

Bioclastic 1 , accretal, peloidal.

1 Common varieties ot bioclastic grams 1 torammiters, bivalves (brachiopods, pelecypods), pelmatozoans (crinoids, echinoids), ostracodes, bryozoans, algae.
336 THE SUPAI GROUP OF GRAND CANYON

FIGURE PL—Distribution of thin sections representing various facies (based on type of grain) in carbonate rocks of Supai Group and Pakoon 

Limestone (McNair, 1951), Grand Canyon region, Arizona. Numbers on maps refer to number of specimens taken from each locality. A, Carbonate mudstone; 8, peloidal grains; C, accretal grains; and D, bioclasts.

Many small foraminifers that apparently have been 

micritized are among the Manakacha peloids.

Terminology for rock fabric

Varieties of fabric as recognized in carbonate rocks of 

the Supai Group (table Pi) can be assigned to various 

classes based on relations of grains to carbonate mud or 

micritic matrix as described by Dunham (1962). These 

classes consist of (1) grainstone in which carbonate mud is 

lacking so that grains rest upon other grains and are 

"grain-supported," (2) packstone, also with particles that 

are "grain-supported," but containing some carbonate 

mud as a matrix, and (3) wackestone in which grains are 

"floating" in carbonate mud, so they are described as 

"matrix-supported."

An additional common type of depositional fabric in 

limestones of the Supai Group is that of rocks normally referred to as aphanitic, in which grains are of microcrystalline (between 0.004 and 0.006 mm) or cryptocrystalline 

(< 0.004 mm) size. Macrocrystalline grains are absent and

the rock is commonly called a carbonate mudstone or 

micrite. In the following discussions the term carbonate 

mudstone will be used in order to emphasize the very fine, 

mudlike texture of the rock.

Fabrics resulting from recrystallization are not uncommon locally in the Supai and consist both of dolostone with 

medium to coarse rhombs or crystals, and of coarsely 

crystalline limestone. The term dolostone is used for the 

rock name; dolomite for the mineral.

The general distribution of the principal rock fabrics 

recognized in the Supai Group is shown in figure P2.

CLASSIFICATION FOR MIXED 

SANDSTONE-CARBONATE 

ROCK TYPES

Rocks of the Supai Group, especially the Manakacha 

and Wescogame Formations, consist in many places of 

mixtures of terrigenous quartz sand and clastic carbonate
PETROGRAPHY 337

FIGURE P2.—Distribution of thin sections representing various fades (based on rock fabric), in carbonate rocks of Supai Group and Pakoon 

Limestone (McNair, 1951). Numbers on maps refer to number of specimens taken from each locality. A, Carbonate mudstone; 6, wackestone; 

C, packstone; and D, grainstone.

grains; all proportions of one to the other are represented. 

Thus, in many sequences of beds, a complete range from 

pure limestone to pure sandstone may occur with relatively small differences in rock appearance. Distinguishing 

between such sandstones and limestones in the field generally is very difficult. The proportion of quartz grains to 

carbonate grains, especially as it approaches the 50-percent 

boundary, can only be accurately determined by percentages obtained through insoluble-residue measurements. 

Furthermore, characteristic features such as crossstratification and red color are common to both.

In this study, the designation of mixed sandstonelimestone units is determined most accurately on the basis

of percent insoluble residue, as illustrated in table P2; more 

than 300 of these determinations were made. For a majority of specimens, however, reasonable approximations of 

grain percentages have been determined from thin-section 

analysis or from point counting.

Subdivision of the mixed sandstone-carbonate rock was 

greatly facilitated by the large number of insoluble-residue 

analyses that were available (fig. Ml). Each thin section 

was assigned to one of the six categories of mixed-rock 

type following comparison with a series of photomicrographs of facies in which the percentage of insoluble 

residue had been determined. The 30-percent and 

70-percent boundaries seem to be especially meaningful

TABLE ?2.—Terminology tor mixed sandstone-carbonate rock

Percent insoluble

0-10 10-30

limestone

30-50

limestone

50-70

Very calcareous

sandstone

70-90

Calcareous

sandstone

90-100

Sandstone
338 THE SUPAI GROUP OF GRAND CANYON

because they approximately correspond to normal interstitial pore space in a packing arrangement of equidimensional grains.

Using only the percent insoluble residue as determined 

by weight, a comparison of histograms for each of the formations of the Supai Group is made. The Watahomigi Formation histogram (fig. MM) shows a typical bimodal 

distribution of percent in soluble material, indicating that 

this formation has a high frequency of pure limestones 

(0-10 percent insoluble) and a relatively smaller mode of 

carbonate mudstone (80-90 percent insoluble).

A bimodal distribution of limestone and sandstone is 

typical of the Wescogame, Esplanade, and Pakoon formations (fig. MM, B, C, D). In contrast, the Manakacha Formation is distinctive in not having a minimum of samples 

in the middle of the histogram (fig. M1B) but, instead, a 

maximum, showing the very transitional or mixed nature 

of the rock in this formation.

PRINCIPAL FACIES OF 

THE SUPAI GROUP

Ten principal facies (fig. P3), designated by the letters A 

through J for convenience in discussion, have been 

recognized in a thin-section study of the Supai Group. Six 

of these facies are types of carbonate rock, three are 

detrital rock, and one gypsum. Other minor types and 

variations are locally present.

The 10 common facies are located and discussed in detail 

in the descriptions that follow on the petrography of each 

formation. The letter designations and diagnostic features 

of these facies are:

A—Mudstone and siltstone, red, argillaceous.

B— Sandstone, commonly calcareous and peloidal, 

mostly cross-stratified.

C—Limestone, aphanitic (carbonate mudstone or micrite), including peloidal types (wackestone).

D—Limestone, peloidal, sandy (grainstone and packstone), commonly cross-stratified, chert-bearing.

E— Limestone, bioclastic (grainstone and packstone), 

locally sandy, cross-stratified, shell fragments 

(brachiopods, pelecypods).

F— Limestone, accretal, algal-foraminiferal (grainstone 

and packstone).

G—Limestone, mixed grains; peloidal, bioclastic (skeletal), accretal (grainstone and packstone).

H—Dolostone and calcitic dolostone, crystalline.

I— Dolomitic sandstone.

J— Gypsum, bedded.

DISTRIBUTION OF THE 

PRINCIPAL CARBONATE 

FACIES IN THE SUPAI GROUP

The distribution of carbonate facies as recognized by 

grain types is shown in figure P4 and summarized as 

follows:

Facies E and G; bioclastic limestones.—Limestones of 

the Supai Group in which the grains are formed in part or 

entirely by fragments of marine invertebrate skeletons 

(bioclasts) seem to be very largely concentrated in the 

western Grand Canyon area (fig. P4). They have been 

recognized in small amounts at a few localities in central 

Grand Canyon, but not in the east. Possibly this distribution is related to the continuous proximity of western 

Grand Canyon to open marine waters of the Cordilleran 

trough (fig. Dl) during deposition of the Supai.

Facies F and G; accretal limestones.—Accretal limestones, including oolitic, oncolitic, and pisolitic, of the 

Supai, have a limited geographic distribution similar to 

that of the bioclastic limestones (fig. P4), but they are even 

less numerous. The greatest number of specimens represented in thin sections are from Pigeon Wash in westernmost Grand Canyon.

Facies D and G; peloidal limestones.—Limestones of this 

type have by far the widest distribution of the varieties 

classified according to grain character (fig. P4). Their distribution is not concentrated in the area of western Grand 

Canyon as with the bioclastic and accretal limestones, but 

is rather evenly distributed throughout the region with 

probably a maximum abundance in the west-central area. 

This implies that an environment favorable to the development and accumulation of peloidal limestone prevailed 

throughout the Grand Canyon embayment during several 

stages of Supai deposition.

Facies C; carbonate mudstones.—Carbonate mudstones 

(micrites) of the Supai are widely distributed from east to 

west in the Grand Canyon region (fig. P5), but are somewhat more abundant in the eastern and central parts than 

in the west (fig. P2A). Reference to paleogeographic maps 

of Pennsylvanian and Early Permian time (figs. D3-D8) indicates that an abundance of carbonate mud accumulated 

along the south side of the Grand Canyon embayment, as 

represented both by this facies and by the wackestones in 

which it forms the matrix. The adjacent southerly landmass apparently provided a protected low-energy setting 

during much of Supai time. The general absence of carbonate mud in the southwestern localities probably reflects 

high energy of the adjacent open seaway.
PETROGRAPHY 339

H

FIGURE P3.—Photomicrographs (x 10) of examples of principal facies 

of Supai Group and Pakoon Limestone (McNair, 1951) recognized in 

Grand Canyon region, Arizona. A, Red argillaceous mudstone; 6, 

calcareous cross-stratified sandstone; C, aphanitic limestone; D,

peloidal sandy limestone; f, bioclastic limestone; F, accretal 

limestone; C, mixed-grain limestone; H, calcitic dolomite; /, 

dolomitic sandstone; andy, bedded gypsum.
340 THE SUPAI GROUP OF GRAND CANYON

ARIZONA 

| WATAHOMIGI FORMATION j WESCOGAME FORMATION

I MANAKACHA FORMATION

2! I

EXPLANATION 

Bioclasts ' 

Accretal grains

Peloids

* Measured sections

FIGURE P4.—Areal distribution of principal types of clasts that form limestones in each formation of Supai Group and in the Pakoon Limestone

(McNair, 1951).

FACES OF THE 

WATAHOMIGI FORMATION

Stratigraphic relations of facies

The Watahomigi is composed of three units or vertical 

subdivisions as described in the chapter on stratigraphy. 

These units find topographic expression as a lower slope, a 

middle cliff, and an upper slope. The middle cliff unit is 

thickest and best developed in the west and seems to be a 

tongue that extends eastward through most of Grand Canyon but is absent at Blue Spring (sec. 4, fig. Al) on the 

Little Colorado River.

Both the lower and the upper units are composed largely

of red argillaceous mudstone and siltstone, and represent a 

single facies, A, as shown in figure P6. In contrast, the 

middle unit, which is composed largely of carbonate rock, 

includes four facies. These are: the mixed-grain limestone, 

G, containing combinations of peloidal, bioclastic, and accretal grains; a relatively pure, accretal limestone facies, F, 

in the thick western sections; a coarsely crystalline 

dolostone facies, H, in the southwest; and a carbonate 

mudstone, C, in the central and eastern parts.

The main body of the mixed-grain limestone, G, that 

constitutes most of the middle unit of the Watahomigi in 

western Grand Canyon not only thins eastward through 

the canyon, but also intertongues with carbonate mudstone (micrite) of facies C in central and eastern Grand 

Canyon (fig. P6).
PETROGRAPHY

114°

341

37°

| ESPLANADE SANDSTONE AND |

<lg RAKOON LIMESTONE

Carbonate mudstone with few or no clasts— 

Micrite and (or) wackestone

EXPLANATION

\\>x

x\v Mostly clastic limestone with little or no carbonate

^^^^ mud—Packstone and (or) grainstone

• Measured sections

FIGURE P5.—Maps showing areal distribution of carbonate mudstone (micrite) and clastic limestone as determined by thin-section examination

in formations of Supai Group and in Pakoon Limestone (McNair, 1951).

Facies C—Aphanitic limestone

Characteristics

Aphanitic limestone that consists of both peloidal 

wackestone and carbonate mudstone represents most of 

the limestone in the Watahomigi of eastern Grand Canyon. From facies C, 56 thin sections, 30 insoluble-residue 

analyses, and 26 determinations of calcium-magnesium 

ratios have been prepared and examined. The following 

generalizations are made from the data.

Facies C is basically a sandy, matrix-supported limestone (wackestone) in which the quartz component ranges 

from very fine grained sand to coarse silt (fig. P7C). Sparfilled openings (fenestrae) or bird's-eye structures are common. The detailed description that follows considers first,

grain types; second, depositional textures and fabrics; 

third, size relationship in quartz-carbonate grains; fourth, 

depositional and postdepositional mineralogy; fifth, 

diagenetic fabric modifications; and sixth, environmental 

interpretation.

Facies C is the most extensive and lithologically constant 

of all the carbonate rock facies in the Watahomigi. It extends far eastward from Whitmore Wash and National 

Canyon where it is interbedded with mixed-grain limestone, both grainstone and packstone, and is exposed 

throughout nearly two-thirds of the Grand Canyon (fig. 

P6). The basal contact is gradational into an underlying 

red argillaceous mudstone. Possibly this facies onlaps the 

Redwall Limestone between the Kaibab Trail, south, and 

Grandview Trail measured sections. Such relationship suggests that the limestone in the eastern area may thin from
342 THE SUPAI GROUP OF GRAND CANYON

SECTIONS NORTH OF 

GRAND CANYON

SECTIONS SOUTH OF 

GRAND CANYON

Facies

EXPLANATION

FEET 

300-

200-

100- 

0-

C

I ' I ' I ' I 

) 10 20 30 4C

19

40 MILES

Red argillaceous mud stone and coarsegrained siltstone

Aphanitic limestone (micrite), including 

peloidal wackestone

Accretal (algal and foraminiferal) limestone 

(grainstone and packstone)

Mixed-grain (peloidal, bioclastic, accretal) 

limestone (grainstone and packstone)

Crystalline dolostone 

Conglomerate

FIGURE P6.—Fence diagram of east-to-west sections showing distribution of facies of the Watahomigi Formation in Grand Canyon region, Arizona. 

Number at babe of each vertical line refers to measured section locality as shown on figure A1.
PETROGRAPHY 343

FIGURE P7.—Photomicrographs (x 10) of rocks of facies in the Wata- facies C, Blue Spring. D, Accretal limestone (packstone) of facies C

homigi Formation, Grand Canyon region, Arizona. A, Argillaceous encrusting foraminifera, Pigeon Wash. £, Accretal limestone

mudstone of facies A, Twentynine Mile Canyon. 6, Very fine grained (grainstone) of facies F, Thunder River Trail. F, Mixed-grain

sandstone of facies B, Whitmore Wash. C, Aphanitic limestone of limestone of facies G, Iceberg Canyon.
344 THE SUPAI GROUP OF GRAND CANYON

onlap, rather than from intertonguing with red mudstone. 

The upper contact of this facies is sharp and, in many 

places, is overlain by a conglomerate which probably 

represents the boundary between strata of Morrowan and 

Atokan age (table Jl).

Grain types

Bioclastic grains.—Scarcity of skeletal material is a 

feature that helps distinguish the aphanitic limestone facies 

from others. Grains of pelmatozoans and small foraminiferal debris occur in some central and western sections such 

as Havasu and National Canyons and Whitmore Wash, 

probably because the sediment was derived from marine 

areas farther west. The only skeletal materials observed in 

sections of eastern Grand Canyon are small indeterminate 

plates, tubes, and calcisphaerids. One exception is at 

Bunker Trail where there occurs a rather coarse pelmatozoan grainstone.

Accretal grains.—Grains of this type are rare in facies C. 

One exception is recorded from Havasu Canyon (sec. 14) 

where, locally, pisoliths display rude concentric lamination into which displacive rhombic calcite has grown. 

Another occurrence is at Kaibab Trail, north, where concentric bands in a clastic dolomitic limestone (wackestone) 

include coated grains.

Peloidal grains. —Two principal size grades of peloidal 

material occur in facies C. One grade ranges from 0.5 to 

0.12 mm in diameter (dominantly coarse-silt size) and is 

typically well sorted. The other size grade ranges from 0.1 

to 2 mm and typically has fair sorting. Grains of these size 

grades commonly occur together. The genetic terms 

"pellet" and "intraclast" probably apply to these size 

classes only in part.

Interbedding of laminated and nonlaminated peloidal 

limestone is not uncommon in this facies. The laminated 

units contain more carbonate mud matrix than do the 

others, and contain little intergranular spar; the 

nonlaminated limestone constitutes a peloidal packstone 

or grainstone with abundant intergranular spar.

Grain sizes

For each thin section of carbonate rock with grains large 

enough to measure, the relative size of quartz and carbonate grains has been recorded. With peloidal grains, 38 

percent were the same size as associated quartz grains, 

whereas 62 percent were coarser. With skeletal grains, 35 

percent were the same size as the associated quartz, 

whereas 65 percent were coarser. All accretal carbonate 

grains were coarser than associated quartz.

Depositional textures and fabrics

Optical similarity between carbonate matrix and the 

micrite of peloids makes recognition of depositional textures difficult, but carbonate mudstones, wackestones, 

packstones, and grainstones are all represented in this 

facies. Some algal accretal limestone occurs in the Kaibab 

Trail, south, section. Carbonate mudstone is most common in southern Grand Canyon sections, especially at 

National and Havasu Canyons, and Bass and Hermit 

Trails (sees. 15, 14, 10, and 9). Grain-supported textures 

are distributed mostly along the western margins of the 

facies, near its transition into other carbonate facies (F, G), 

although a few such textures, together with quartz sandstones, exist near the eastern part of the middle or carbonate rock unit of the Watahomigi Formation. Laminated 

fabrics are most common in the eastern Grand Canyon 

although they are also abundant in the National Canyon 

section.

Mineralogy

Most of the quartz that occurs in facies C is detrital. The 

quartz grains are predominantly coarse silt or very fine 

grained sand. They are largely angular to subangular and 

are well sorted. Based upon insoluble-residue determinations, much of this facies has an average quartz content of 

about 18 percent. Seventy percent of all samples contain 

between 10 and 30 percent insoluble residue. Typical rocks 

of this facies are sandy or silty peloidal wackestones.

Authigenic quartz in the form of chert or jasper occurs, 

commonly replacing coarse, blocky, void-filling spar. In 

facies C, cryptociystalline varieties of quartz occur rarely 

as fillings in former pore spaces or in fractures and rarely 

as reworked chert or jasper lithoclasts. In a single 

specimen, from the Kaibab Trail, north, measured section 

(8), coarse rhombohedral calcite with wavy extinction was 

seen to have replaced cryptociystalline quartz. Replacement of this type probably was late diagenetic, following 

development of a coarse cement. However, the entire process was prior to erosion of the rock and incorporation of 

clasts in the Atokan-age conglomerate above the middle or 

cliff unit of the Watahomigi.

A complete discussion of the various types of calcite in 

the Watahomigi is beyond the scope of this study; however, one type called vadose silt and crystal silt by 

Dunham (1969) and rhombic silt by Folk (1973) and microspar rhombs (Folk and Land, 1975) merits some discussion 

because of its possible genetic implication. This calcite consists of silt-size grains filling voids as internal sediment. It 

is characteristically geopetal, allowing tops to be determined. In many places this silt-size calcite underlies blocky 

calcite spar. As suggested both by Dunham and by Folk, it 

probably results from diagenesis in vadose water or water
PETROGRAPHY 345

of considerably less than normal marine salinity. This type 

of calcite occurs in nine measured sections of the Watahomigi, both north and south of Grand Canyon.

Muscovite is an accessory mineral in the fine-grained 

parts of facies C, but it is considerably less abundant than 

in the overlying formations of the Supai.

Based on 26 calcium-magnesium determinations, dolomite is not a common mineral of this facies. At Tuckup 

Canyon (sec. 18) one sample of peloidal packstone with 

silt-size carbonate grains is classed as a calcitic dolomite. 

Dolomitic limestone forms part of the carbonate rock 

at Havasu Canyon and Kaibab Trail, north, localities 

(sees. 14, 8) and magnesian limestone forms part of the lithology at National and Havasu Canyons and Hermit 

Trail (sees. 15, 14, and 9). The peloidal wackestone fabric 

of these rocks, as well as the grains interpreted as vadose 

silt, suggest that dolomitization was in a supratidal environment; however, the small amount of dolomite is difficult to explain in this setting.

Diagenetic modifications

One of the most conspicuous attributes of facies C is 

bird's-eye structure consisting of calcite-filled openings or 

fenestrae. These openings are polygenetic voids, which are 

larger than normal pore spaces in the rock. Several examples of enlarged intergranular cavities, similar to those 

in belteroporic fabric described by Sander (1951), have 

been observed. This fabric may form by vadose water 

flushing through primary intergranular pore spaces or 

along desiccation cracks in such a way as to enlarge the 

pore spaces. Gas bubbles may also form voids. One characteristic of the fabric, as seen in thin section, is that adjacent to large voids or probable water courses the pore 

walls are more rounded and smooth than are those adjacent to narrow water courses.

Voids of an unusual type, which may or may not share a 

common origin, seem to have been formed as burrows or 

bore holes of organisms. Many are vertical, some follow 

bedding. Many have inner linings of carbonate silt and 

these linings are subparallel to the walls of the openings. 

Mostly, inner linings have spar on the sides and many 

are segmented. The impression is given that spar partially 

filled the cavities, after which deposition of micrite or siltsize carbonate material occurred. Later came erosion or 

breakage of the fine coating, and finally a filling with spar.

Definite fractures do not have the same characteristic inner lining as do the cavities. The lining parallel to bedding 

in some specimens forms a compartmentalization within 

the large openings. Peloids of the typical 0.05-0.1-mm-size 

range do not seem to be associated with or to fill any 

of these burrowlike openings. In at least one example, the 

silt lining seems to have broken away from the surrounding peloidal rock as if a burrow surface was partially cemented and was of a greater strength than the surrounding 

matrix.

Interpretation of environment

The aphanitic limestone of facies C with its characteristic carbonate mud (micrite) and its considerable 

peloidal content is interpreted as having formed in a lowenergy, shallow-water environment, probably shallow 

subtidal. Possibly the environment was intertidal or supratidal, although such sites commonly show characteristic 

tidal flat deposits including well-developed algal 

stromatolites and channels with distinctive sedimentary 

structures. In the easternmost part of the Grand Canyon 

area, strata of facies C seem to onlap a topographic high of 

the underlying Redwall Limestone (fig. P6). The common 

occurrence of vadose silt filling cavities and voids in the 

sediment suggests, although it does not prove, intermittent 

subaerial exposure. The abundance of carbonate mud 

matrix among peloids favors the concept of quiet waters.

Facies F—Accretal 

(algal-foraminiferal) limestone

Characteristics

Twenty thin sections representing six measured sections, 

supplemented by 13 insoluble-residue analyses and 11 

calcium-magnesium ratio determinations have been used 

in preparing this description of facies F, an accretal (algalforaminiferal) limestone (grainstone). Uniformity of depositional texture and distinctive character of grains make 

this facies the easiest to recognize of those comprising the 

Watahomigi Formation.

The base of facies F grades into the underlying mixedgrain limestone (G). It occurs exclusively in western Grand 

Canyon (fig. P6) and intertongues eastward from Separation Canyon (sec. 34) and Whitmore Wash (sec. 22) into 

red mudstone. Because the mixed-grain limestone (G) apparently is a time equivalent of the carbonate mudstone 

and peloidal-wackestone (C) to the east, the overlying accretal limestone (F) probably is younger than the carbonate 

mudstone and peloidal-wackestone facies (C). Thus, the 

accretal limestone facies may be represented in eastern 

Grand Canyon by the hiatus below the conglomerate of 

Atokan age and the underlying aphanitic limestone facies 

(C) of carbonate mudstone and peloidal wackestone that 

forms the middle cliff unit.

Grain types

Peloidal grains are scattered throughout facies F (recorded 

in 12 of 20 thin sections), but they are not abundant and 

are relatively inconspicuous because of the greater size
346 THE SUPAI GROUP OF GRAND CANYON

of associated accretal grains. Several types of peloids 

have been recognized, and they range in size from 0.04 to 

0.4 mm. Many large peloids contain internal structures 

that may indicate origin as lithoclasts. Some peloids consist of microspar. Others have a stumpy rodlike shape, and 

still others appear abraded. Most of the peloids are round 

to elliptical in cross section.

Bioclastic grains in facies F are of many varieties. Nearly 

every thin section contains some skeletal material representative of three or more animal phyla. Pelmatozoan 

plates, encrusting foraminifers, gastropods, brachiopods, 

and bryozoans are the most common types. Less common 

are trilobites (Twin Springs Canyon, sec. 25), ostracodes 

(Guano Cave, sec. 26), and vertebrate fragments (Hidden 

Canyon, sec. 30a).

Accretal grains are both the most common and most distinctive grain type of facies F. These grains are composed 

of Girvanella-\ike "algae," many of which are intergrown 

with the encrusting foraminifers Apeterrinella sp. or 

Hedraittes sp. as determined by L. G. Henbest (written 

commun., 1963). These intergrowths may or may not encrust skeletal fragments. Similar associations among grains 

have been called Osagia (Twenhofel, 1919; L. G. Henbest, 

written commun., 1963; and Toomey, 1969).

An important difference between the Supai accretal 

grains and those originally described as Osagia by 

Twenhofel (1919) is that the Supai variety is a spherical to 

rounded-plate shape, rather than a spherical to fusiform 

shape. The Supai encrusting foraminifers, furthermore, are 

associated with grains in 75 percent of the samples studied, 

whereas such foraminifers are not mentioned in Twenhofel's description. Cores of the grains, where visible, are 

either rounded or angular. Spar shell fragments constitute 

the most typical core material, but pelmatozoan plates are 

also common. Peloidal material and, rarely, microspar, 

form cores.

The radius of most cores appears to be less than the 

thickness of the accretionary crust; however, the angle of 

the thin-section slice with respect to the accretal grain axis 

may prejudice an observation of this feature. In 75 percent 

of thin sections examined, the grains are better sorted than 

are the cores within them. Most deposits of accretal grains 

exhibit good sorting, implying that the accretionary process accounts for this texture.

Grain sizes

Most accretal grains range in size from 0.4 to 1.0 mm 

(coarse sand size), but a few are very coarse or even 

granule size. Only a small percentage (20 percent) of the 

accretal grains have a smooth external surface. In many 

places where a smooth surface occurs, encrusting foraminifers have attached themselves, causing a rough surface to 

result. In only two samples (10 percent) were the encrusting skeletons of the foraminifers truncated by abrasion. Broken material containing encrusting forams was 

not observed.

Depositional textures and fabrics

Texture and fabric of the bioclasts of facies E and G contribute to an understanding of the nature of transport of the 

grains. About 80 percent of the samples studied were grainstone (no matrix) and 95 percent were grain-supported. 

However, only 40 percent of the samples show any stratification. Preferential orientation is a result of the platelike 

form of many of the cores, and foliation is not apparent 

when plate-shaped cores (on which accretion material can 

form) are rare or absent. Field observations indicate that 

this facies is not cross-stratified in most localities—a single 

exception being at Twin Springs Canyon.

The accretal limestone (facies F) is the purest carbonate 

unit in the Watahomigi Formation. Its insoluble-residue 

content averages 6.6 percent. Mostly the quartz grains are 

finer grained than those associated with skeletal or peloidal 

grains of other facies. Although this facies is one of the 

purest limestones, it is adjacent to facies of red argillaceous 

mudstone at various places such as the Guano Cave and 

Separation Canyon measured sections.

Diagenetic modifications

Jasper "bands" or veins occur in 7 of 20 of the sampled 

outcrops of facies F. Secondary silica is present in 8 of 20 

thin sections, but is volumetrically less important than in 

other facies. Two types of silica exist: (1) cryptocrystalline 

silica that in many places replaces pelmatozoan material 

and, in one locality, replaces spar; and (2) euhedral quartz 

that occurs as overgrowths on silt or sand grains.

Eleven calcium-magnesium analyses of rocks from facies 

F showed very pure limestone; only one analysis indicated 

a magnesian limestone.

Calcite cement typically is a blocky spar (void-filling 

cement). Only three samples contained silt-size rhombohedral cement (Folk, 1962) or vadose silt (Dunham, 1969). 

These samples were from Guano Cave, Snap Canyon, and 

Hidden Canyon (fig. P6, sees. 26, 27, 30). No prismatic 

calcite cement was noted in this facies.

Examples of animal burrows or of spar-filled openings, 

typical of the carbonate mudstone and peloidal limestone 

of facies C and G, were few.

Interpretation of environment

The association in facies F of algae and of certain invertebrate fossils seems to imply deposition in shallow marine 

waters. However, this association might have resulted 

from similar temperatures, salinities, or other ecological
PETROGRAPHY 347

factors, rather than from water depth. Accretal grains of 

the type represented, like ooids, commonly are considered 

to be the product of high-energy conditions. On the other 

hand, lack of cross-stratification and the general absence 

of abrasion on delicate encrusting foraminifers, oppose 

this interpretation.

Facies G—Mixed-grain limestone

Characteristics

The mixed-grain limestone (facies G) of the Watahomigi 

Formation consists of rock types that are not easily characterized by a simple lithologic description. Diversity of 

grain form is one of the most unifying attributes of this 

facies. The rock contains abundant peloids (about 75 percent of all samples), numerous skeletal fragments (in approximately 88 percent of the samples), and accretal 

grains, mostly biogenic (in about 35 percent of the 

samples).

Limestones of facies G have a considerable range in the 

amount of lime-mud matrix included and contain both 

grainstones and packstones (table Pi).

Mixed-grain (peloidal, skeletal, accretal) limestone of 

facies G merges into other facies in all directions. At 

Iceberg Canyon (fig. P6, sec. 31) it overlies crystalline 

dolomite (facies H); at Guano Cave, Twin Springs Canyon, Hindu Canyon, and Blue Mountain Canyon, measured sections 26, 25, 35, and 19, it grades downward into 

conglomerate and red mudstone of facies A; at Bridge Canyon (sec. 35) it overlies relatively pure bioclastic grainstone and packstone (facies E). Farther north it overlies red 

mudstone (facies A) and crystalline dolomite (facies H). To 

the east at Whitmore Wash and near National Canyon sections 22 and 15 interbedded relations suggest that it is 

laterally equivalent to the carbonate mudstone and 

peloidal wackestone of facies C of eastern Grand Canyon.

Grain types

Shapes of peloids in facies G constitute a wide range including spherical, ovoid, and irregular. Many peloids in 

the 0.1-0.2-mm-size class contain vague internal structures, indicating an origin other than as fecal pellets. Many 

peloids of large size within the same thin section have different fabrics. Some contain quartz silt, whereas others are 

composed of translucent microspar. Still others are composed of very opaque micrite. In general, peloids of this 

facies are not well sorted like those in the carbonate 

mudstone of facies C. Almost all associated quartz grains 

are finer than the peloidal grains.

Presence and diversity of fossil fragments help to distinguish facies G (mixed-grain limestone) from its eastern 

lateral equivalent—the carbonate mudstone of facies C.

Nineteen of 34 samples had three or more animal phyla 

represented within a sample, and 83 percent had at least 

one phylum included. Compared to other facies in the 

Watahomigi Formation, varieties of skeletal components 

are numerous.

Pelmatozoan plates are the most common bioclastic 

forms in the mixed-grain facies. Other major skeletal constituents are small fragments of foraminifers, undifferentiated mollusks, brachiopods, bryozoans, and algae, 

mostly Girvanella types. Echinoid spines, ostracodes, calcisphaerids, trilobites, unidentified pelmatozoan plates, 

gastropods, and vertebrate fragments are less numerous 

and are only minor constituents.

Accretal grains are the least common grain type in facies 

G; they occur in minor amounts in about one-third of the 

thin sections. Accretal grains of algae and foraminifers are 

the most common types; micrite-coated skeletal grains 

constitute the remainder of the accretal grains in this 

facies.

Grain sizes

Two major size-groups of peloids exist in the mixedgrain facies (G). One is small, typically ranging from 0.05 

to 0.1 mm; the other is larger, ranging from 0.1 to 0.2 mm. 

Other peloids are rare. One very small, well-sorted variety 

ranges in size from 0.04 to 0.05 mm and has a rounded 

cylindrical shape. This rare type has been found only at 

Hindu Canyon (sec. 35).

Only a few samples of facies G contain quartz grains 

equal in size to the carbonate grains (peloids). In more than 

90 percent of the samples, carbonate grains are coarser 

than quartz. The average insoluble-residue (quartz-grain) 

content of this facies is 11.4 percent; however, more than 

two-thirds of the samples contain less than 10 percent insoluble residue.

Depositional textures and fabrics

About two-thirds of the thin sections of this facies (G) 

are from grain-supported limestone; however, more than 

two-thirds contain appreciable amounts of carbonate mud. 

Packstone (containing carbonate mud) is more common 

than grainstone (lacking carbonate mud). A plotting of the 

grain-support relationships of the facies (fig. P5) shows 

that in the west, south, and north parts of the Grand Canyon region, more grains are grain-supported than otherwise. Only in the east are more than 50 percent of the 

samples mud-supported.

Most beds of this facies are horizontally stratified.

Mineralogy

Detrital quartz of coarse silt size makes up most of the 

insoluble-residue content of this facies. Some of the quartz 

is very fine grained sand, much of it is well sorted and
348 THE SUPAI GROUP OF GRAND CANYON

angular to subangular. Secondary silica is considerably 

less common in this facies than in the carbonate mudstone 

and peloidal wackestone of facies C. Some reworked clasts 

of chert occur at Whitmore Wash and total replacement by 

chert of a peloidal wackestone was noted at Guano Cave. 

Replacement by small fine-grained euhedral crystals of 

quartz at both Guano Cave and Iceberg Canyon is recorded. At Iceberg this replacement is most concentrated 

near fractures, suggesting that the euhedral quartz is late 

diagenetic to epigenetic in origin. A small amount of interstitial cryptocrystalline silica occurs at Twin Springs 

Canyon.

The most common interstitial cement is blocky calcite 

spar. Although some microspar is present (interpreted as 

the vadose silt of Dunham, 1962), it is less common in this 

facies than in the microcrystalline, lateral equivalent 

(facies C) to the east. Dolostone is rare. Peloidal carbonate 

rocks (wackestones) at Iceberg and Hidden Canyons were 

determined to be calcitic dolostone and dolomitic limestone, respectively. The only pure dolostone is a coarsely 

crystalline rock from the Guano Cave locality. This sample is anomalous, for Ca-Mg analyses of 17 other samples 

indicate a predominant calcite composition for the carbonate part of the mixed-grain facies.

Diagenetic modifications of fabric

Chief among processes of modification represented in 

lateral equivalents of the mixed-grain facies (G) were those 

that formed openings. Micrite-filled linear burrows and 

borings are also numerous. In the mixed-grain facies, 

however, such structures are rare or absent. Belteroporic 

fabrics are also missing.

Porosity is difficult to appraise in the mixed-grain facies. 

Carbonate mud fills a substantial amount of the intergranular areas. Because peloids are the major grain constituent, 

an interconnected porosity could not readily be formed 

from molds of dissolved skeletal debris. The absence of 

openings suggests that subaerial exposure was not characteristic of this facies.

Facies H—Coarsely 

crystalline dolostone

Characteristics

Both chemical analyses and stained thin sections have 

been used to identify dolostones of the Watahomigi. Many 

dolostone beds are a light cream color as seen in the field, 

in contrast to other carbonate rocks that have grayer 

tones. Most dolostones of the Watahomigi are coarsely 

crystalline.

Texture and fabrics

Floating quartz grains and phosphatic skeletal parts attest to a replacement origin. In many places where silicification is present, the primary limestone fabric of the accretal facies (F) is readily seen in the silicified rock, indicating that dolomitization came after silicification. 

Chemical analyses show that most of the dolomitized 

rocks are true dolostone, but some samples are dolomitic 

limestone and some are calcitic dolostones.

Interpretation of genesis

The crystalline dolostone facies (H) occurs only at the 

Iceberg, Snap, and Andrus Canyon measured sections (31, 

27, and 24). At Iceberg Canyon it overlies a red mudstone 

that forms the lower slope unit of the formation, but 

northeastward toward Snap Canyon, the basal red 

mudstone unit is progressively thinner as it onlaps a high 

area of the underlying Redwall Limestone. Finally, at Snap 

Canyon (sec. 27) crystalline dolostone rests on the Redwall 

Limestone. Farther east, at Andrus Canyon, thin beds of 

crystalline dolostone are interbedded with red argillaceous 

mudstone. This interbedded relationship suggests intertonguing, and the dolostone apparently is a lateral equivalent of the argillaceous mudstone. Stratal correlation between Iceberg Canyon and Guano Cave sections (31 and 

26) implies that the crystalline dolostone may also be a 

lateral equivalent of the lower mixed-grain limestone facies 

(G) in that area.

FACIES OF THE 

MANAKACHA FORMATION

Stratigraphic relations of facies

Throughout much of the Grand Canyon region, the 

Manakacha forms two distinct topographic units (fig. C5): 

the lower unit is a massive, persistent cliff commonly referred to as the "lower cliff unit of the Supai"; it is overlain 

by a relatively small slope called the "middle slope unit of 

the Supai."

The massive cliff unit is largely formed of resistant 

calcareous sandstone and sandy limestone, cross-stratified 

on a medium-to-large scale. In contrast, the weak upper 

slope unit consists mostly of red mudstone in eastern 

Grand Canyon, and of bioclastic limestone in the west. Between the eastern and western areas, near Tuckup Canyon, Toroweap Valley, and Whitmore Wash (sees. 18, 21, 

and 22) in central Grand Canyon, the slope unit seems to 

be largely or entirely missing as shown by a relative thinness of the formation at those localities (fig. P8). This local
PETROGRAPHY 349

SECTIONS NORTH OF 

GRAND CANYON

SECTIONS SOUTH OF 

GRAND CANYON

FEET

300 -i

200 -

100-

0

19

0 10 20 30 40 MILES

Red argillaceous mudstone—Calcareous to very 

calcareous

Peloidal sandstone—Calcareous to very calcareous, 

cross-stratified

Peloidal(grainstone and packstone)limestone— 

Sandy to very sandy, cross-stratified, locally chertbearing; includes some accretal grains

Bioclastic(grainstone and packstone)limestone— 

Locally sandy

Dolostone, coarsely crystalline 

Conglomerate

FIGURE P8.-Fence diagrams of east-to-west sections showing distribution of facies of the Manakacha Formation, Grand Canyon 

region, Arizona. Sandstone and limestone designations determined 

by percent insoluble residue. Limestone is rock with less than 50 percent insoluble residue; sandstone, greater than 50 percent insoluble 

residue. Number at base of each vertical line refers to measured section locality as shown on figure A1.
THE SUPAI GROUP OF GRAND CANYON

•SafiaJ^^j^w^-^^awM H &^^i£^$0Xvm* • ^feP^^M*^^^; £

FIGURE P9.—Photomicrographs (x 10) of typical specimens from 

principal facies of Manakacha Formation. A, Facies A, red 

argillaceous mudstone, Blue Mountain Canyon, sec. 19. B, Facies B, 

calcareous pelcidal sandstone, fine- to medium-grained, Thunder

absence of the slope unit probably is the result of postAtokan erosion in that area.

Conventional facies— 

Stratigraphic relations

Four of the principal facies recognized in the Supai 

Group compose the Manakacha Formation of the Grand 

Canyon. These are: A, red argillaceous mudstone; B, peloidal, calcareous to very calcareous sandstone; D, sandy 

to very sandy, peloidal limestone; and E, bioclastic limestone, locally sandy.

The distribution of facies in the Manakacha (fig. P8) illustrates well the trends, both horizontally and vertically,

River Trail, sec. 12. C, Facies D, peloidal sandy limestone with some 

bioclastic grains, Toroweap Valley, sec. 21A. D, Facies E, bioclastic 

limestone with micritic matrix, Hidden Canyon, sec. 30.

in proportions of detrital sediment to carbonate sediment 

and in high-energy deposits to low-energy deposits.

Facies A—Red argillaceous 

mudstone

The red argillaceous mudstone constituting facies A in 

the Manakacha Formation commonly is calcareous to very 

calcareous. As seen in thin section, much of this mudstone 

contains a large percentage of silt-size quartz grains that 

are angular and well sorted, and that occur in a matrix of 

dark clay or ferruginous material (fig. P9).

This facies occurs extensively in the eastern part of the 

area (Blue Spring, Bunker Trail), but also is well repre-
PETROGRAPHY 351

sented in the southwestern part, as in the vicinity of Blue 

Mountain Canyon. The distribution pattern means that 

the sources of mud probably were to the southeast and 

south, as confirmed by tongues of red mudstone that extended from these areas outward across an embayment of 

Atokan age that connected the Cordilleran geosyncline in 

the west with the Paradox basin to the northeast (fig. D4).

Facies B—Peloidal, calcareous to 

very calcareous sandstone

Peloidal, calcareous to very calcareous standstone of 

facies B (fig. P9) is a highly cross-stratified rock consisting 

largely of quartz sand, but containing peloidal limestone 

grains in various proportions and, in many places, grading 

into sandy or very sandy limestone of facies D (fig. P8). 

The boundary between these facies is considered to be 

where 50 percent of the rock is HCl-soluble and 50 percent 

HCl-insoluble. Many strata are close to this boundary and, 

therefore, may be similar in appearance even though some 

are sandstone and others limestone; they can be differentiated with assurance only through insoluble-residue 

measurements.

Facies B, and also facies D into which B grades laterally, 

contain some skeletal and accretal grains as well as the 

more abundant and characteristic peloidal grains.

Accretal grains, although uncommon, are represented 

by sparse oolitic grainstones in facies B and D at a few 

localities in the Manakacha as at Blue Mountain Canyon, 

National Canyon, Pigeon Wash, and Hidden Canyon 

(sees. 19, 15, 28, 30).

The peloids seem to be polygenetic. They are not 

restricted to a specific size range in a given area as are those 

of the middle unit in the Watahomigi, but most of them are 

similar in size to the quartz grains with which they are 

associated, suggesting similar conditions of sorting.

Peloids in this facies commonly exhibit an internal structure suggesting an origin either as rounded intraclasts or as 

micritized small foraminifers. In a few places micritized 

small foraminifers compose most of the rock.

Bioclastic grains in this facies (B) mostly record transportation with abrasion of particles. Pelmatozoan 

plates—many well rounded—and small foraminifers in 

particular, seem to have undergone extensive transport 

and to have accumulated as concentrations more than did 

most other skeletons.

Facies D—Sandy to very sandy 

peloidal limestone

Limestone of facies D (fig. P9C) is highly cross-stratified 

like sandstone of facies B. It differs from that facies in containing a greater amount of carbonate peloids and fewer

quartz grains. It is grain supported and is designated as 

either grainstone or packstone (table Pi). In brief, it may 

be without a carbonate mud matrix or may contain carbonate mud in moderate amounts. Some limestones of this 

facies are jasper-bearing.

Facies B and facies D, which together represent essentially all of the conspicuously cross-stratified rocks of the 

Manakacha, extend from east to west across the entire 

region as shown in a cross section (fig. P8). From this illustration, it is apparent that the sandstone of facies B is more 

concentrated in the east and the limestone (facies D) in the 

west. However, also evident from the diagram, there is a 

progressively greater sandiness upward in the formation, 

resulting in facies B overlying facies D in most places.

Carbonate grains in facies D are like those of facies B described in the preceding section but are more numerous 

(>50 percent). In both facies, the grains consist dominantly of peloids and, to a small extent, of skeletal debris 

and accretal types.

Facies E—Bioclastic limestone

Limestone of facies E is skeletal and commonly referred 

to as bioclastic (fig. P9D). It may or may not contain a carbonate mud matrix, but generally is grain-supported and 

includes both grainstone and packstone. Locally it contains some quartz sand. This facies occurs only in the upper part of the formation and is distributed throughout the 

western and southwestern parts of the Grand Canyon area 

(fig- P8).

Alternative facies classification

The transitional nature of the highly cross-stratified 

units of sandstone and limestone that form a major part of 

the Manakacha is apparent both in the field and in thin section. Because of this gradation from one rock type into 

another, an alternative facies classification was devised by 

Walter Pierce while making petrographic studies. In this 

classification the relatively pure sandstone (>70 percent 

quartz sand) and the relatively pure peloidal limestone 

(> 70 percent peloidal carbonate) are considered as distinctive facies (B' and D', respectively). A gradational mixture 

of calcareous peloidal sandstone (>30 percent peloidal 

carbonate) and sandy peloidal limestone (>30 percent 

quartz sand) is considered facies B'D'.

The most notable feature of this classification that is not 

apparent from the more orthodox classification is the 

widespread distribution and abundance of facies B'D', 

which consists dominantly of cross-stratified sandstone 

and peloidal limestone with little or no matrix of carbonate 

mud. Secondly, relatively pure sandstone of facies B' is 

largely restricted to the area of middle Grand Canyon, 

whereas the rocks of facies D', relatively pure limestone
352 THE SUPAI GROUP OF GRAND CANYON

with little quartz sand, are mostly in western Grand Canyon and, to a small extent, in eastern Grand Canyon. 

Argillaceous mudstone (facies A) occurs principally along 

the southern and eastern margins.

The several types of grain—peloidal, bioclastic, and accretal—that occur in facies B' D' and in D' are the same as 

those described earlier under the title "facies B" (Manakacha Formation). In texture, grain form, and mineralogy 

the carbonate rocks are alike, in general, throughout the 

region so the difference in classifications is one involving 

the arbitrary boundaries selected to show the proportions 

of quartz sandstone to peloidal limestone. In the alternative classification suggested by Pierce, the 30-percent 

and 70-percent boundaries are believed to approximate the 

limits of carbonate-grain support and quartz-grain support, respectively. Further, distribution of the remaining 

intermediate 40 percent, represented by facies B'D', emphasizes the extent of transition between soluble and insoluble fractions.

Facies B'D', alternative

The mixed quartz sand and carbonate peloids of facies 

B'D' are characterized by cross-stratification throughout, 

and by a lack of algal-foraminiferal grains. Both of these 

features imply a high-energy environment. The quartz is 

largely angular to subangular and is well sorted, especially 

within individual laminae. Rounded jasper and chert 

grains are numerous, one or two occurring in nearly every 

thin section. Silt-size peloids and quartz grains are 

numerous and muscovite flakes are common accessories.

Cross-stratified rocks of facies B'D' in the Manakacha 

apparently differ from those of the overlying Wescogame 

Formation. In the Manakacha, bimodal quartz is relatively 

rare, but it is common in the Wescogame. In the Manakacha, secondary silica in the form of jasper, both replacing carbonate rock and locally filling vugs, is especially common; it is far less abundant in overlying formations.

Interpretation of facies

Interpretation of the facies distribution described above 

strongly suggests several features of the depositional environment and paleogeography during Atokan time. First, 

the Grand Canyon embayment was the recipient of an 

abundance of relatively high-energy deposits (facies B', 

quartz-sand; and D', peloidal carbonates) as illustrated by 

the abundance of cross-stratification and by the relatively 

small amount of carbonate mudstone (facies C), either as 

matrix or in beds. Second, areas of pure carbonates (facies 

D') in the extreme west and, to a small extent in the east, 

suggest marine connections with the Cordilleran seaway

and the Paradox basin, respectively, whereas the central 

area of pure sand (facies B') reflects greater distance from 

the permanent marine bodies. Finally, areas of argillaceous 

red mud (facies A) to the south and southeast probably indicate proximity to sources along the southern margins of 

the embayment (fig. D4).

FACIES OF THE 

WESCOGAME FORMATION

Stratigraphic relations of facies

The Wescogame Formation of the Grand Canyon consists of two dominantly detrital facies and two of carbonate sediments. The detrital strata are referred to facies 

A of the Supai Group, composed of red argillaceous mudstone with some carbonate mudstone, and to facies B, 

which is a cross-stratified calcareous sandstone. Facies of 

the carbonate sediments consist of facies E, a sandy to very 

sandy, cross-stratified limestone with bioclasts, but no 

carbonate-mud matrix (grainstone), and facies H, which is 

thin-bedded dolostone. Facies H includes some skeletal 

limestone (packstone of facies E).

The distribution of these facies is indicated in the fence 

diagrams, figure P10. Cross-stratified calcareous sandstone of facies B comprises a major part of the formation 

throughout the area. In the west, this merges into the very 

sandy bioclastic limestone of facies E, which likewise is 

conspicuously cross-stratified. In the extreme northwest at 

Hidden Canyon (sec. 30), the lower part of the formation 

is dolostone (facies H), but no readily apparent explanation is available for its presence in that area. Red argillaceous mudstone of facies A occurs almost exclusively in 

eastern Grand Canyon where it probably developed in 

areas of low energy bordering channelways that connected 

the Cordilleran marine waters with those of the Paradox 

and Sonora basins during Virgilian time (fig. D7). In the 

southeast, the argillaceous mudstone sections are thicker 

than average for the Wescogame so may represent an area 

of deltaic or alluvial accumulation.

Deposits of jasper, both interbedded and cross-cutting, 

which are abundant in the two underlying formations of 

the Supai Group, are nearly absent in all facies of the 

Wescogame. The significance of this feature is not known, 

but probably it stems from the general scarcity of carbonate rocks in the Wescogame in all but the westernmost 

areas.
PETROGRAPHY 353

\

SECTIONS NORTH OF 

GRAND CANYON

SECTIONS SOUTH OF 

GRAND CANYON

FEET 

300-

200-

100- 

oC

i | i | i | i 

10 20 30 40 MILES

Red argillaceous mudstone 

Cross-stratified sandstone 

Peloidal limestone 

Bioclastic limestone 

Thin-bedded dolostone 

Conglomerate

FIGURE P10.—Fence diagrams of east-to-west sections showing distribution of facies of the Wescogame Formation in Grand Canyon region. 

Arizona. Number at base of each vertical line refers to measured section locality as shown on figure A1.
354 THE SUPAI GROUP OF GRAND CANYON

*Sm^^^^^^^m?-^^^

SS^ S^^'M^^f^feSfe^ :'M^Mi^#A!P^f

'v&#&iif:'* 7-:^\^&fyi&v. *,.r"?^.,^

FIGURE PH.—Photomicrographs (x 10) of principal facies of Wescogame Formation recognized in Grand Canyon. A, Facies A, red 

argillaceous mudstone and carbonate mudstone, Kaibab Trail, south, 

sec. 7. 6, Facies B, fine-grained calcareous to very calcareous sandstone; cross-stratified. Hermit Trail, sec. 9. C, Facies B, very fine 

grained calcareous sandstone, Hermit Trail, sec. 9. D, Facies E, sandy to very sandy, bioclastic limestone (grainstone); cross-stratified, 

Snap Canyon, sec. 27. E, Facies E-H, bioclastic limestone 

(packstone) interbedded with thin-bedded dolostone, Guano Cave, 

sec. 26.

Characteristics of facies

Fades A; red argillaceous mudstone.—Argillaceous 

mudstone of facies A is restricted to the eastern part of 

Grand Canyon. The red color of this rock appears in thin 

section to result from ferruginous matrix in a quartz 

siltstone. The quartz grains are angular and medium- to
PETROGRAPHY 355

well-sorted (fig. Pll). Muscovite is a common accessory 

mineral. Some aphanitic limestone (carbonate mudstone), 

mostly nonlaminated, is associated with the mudstone. In 

the lower part of the Bunker Trail section (5), laminated 

carbonate mudstone (micrite) contains spar-filled fenestral 

areas; at Twentynine Mile Canyon (sec. 2) in the upper 

part of the section, belteroporic fabric as described by 

Sander (1951) is present.

Fades B; calcareous to very calcareous, cross-stratified 

sandstone.—This is the most widespread facies of the 

Wescogame Formation. It consists of quartz sand, which is 

mostly very fine grained to fine grained and subangular, 

and it has fair to good sorting on the Payne scale. It grades 

into bioclastic limestone of facies E to the northwest and 

west.

In the western third of Grand Canyon much of the 

quartz in this facies is bimodal, with the inclusion of a 

sparse medium- to coarse-grained sand component most of 

which is well rounded. These large quartz grains are conspicuous but not volumetrically important. Rounded chert 

grains are a common accessory.

The carbonate content of facies B results both from calcite cement and from allochthonous grains. Bioclastic 

grains are the most common type, but peloidal grains also 

occur. Pelmatozoan plates are numerous and widespread. 

Calcite cement is especially common in the southeastern 

measured sections.

Many quartz grains contain postdepositional quartz 

overgrowths. Secondary silica preceded calcium carbonate 

in the cementation process. Where quartz overgrowths are 

common, marine detritus such as peloids and bioclasts 

seem to be scarce or absent.

Facies E; sandy to very sandy, cross-stratified, bioclastic 

limestone.—This is the most common lithology (fig. Pll) 

in the northwestern area of Wescogame distribution. The 

quartz sand resembles sand of facies B. Bimodal sand is 

locally common and a grain-supported texture is characteristic. Most grains are skeletal fragments, but in approximately one-third of the thin sections examined, high proportions of peloids occur. Two measured sections included 

accretal grains: oolitic grainstones at Hidden Canyon (sec. 

30) and oolitic packstones at Pigeon Wash (sec. 28). 

Numerous fragments of encrusting foraminiferal tests occur in thin sections. The surfaces from which these tests 

were dislodged probably were flat.

Facies E-H; bioclastic limestone and thin-bedded dolostone.—In parts of the westernmost Grand Canyon area, 

facies E, which consists of sandy bioclastic limestone; commonly cross-stratified, is closely associated with thinbedded dolostones of facies H. Where this combination occurs the term facies E H is applied, indicating that it is not 

practical to separate these types at the scale used.

Because the largely bioclastic grains of facies E are

rounded and form cross-strata, they imply an environment 

of high energy. The genesis of the associated thin-bedded 

dolostone has not been determined.

FACIES OF THE 

ESPLANADE SANDSTONE 

AND PAKOON LIMESTONE

Stratigraphic relations of facies

Seven of the facies characteristic of the Supai Group are 

recognized in the Esplanade Sandstone and Pakoon Limestone (McNair, 1951). The cross-stratified calcareous sandstone, referred to as facies B, constitutes the dominant rock 

in the Esplanade throughout nearly all of the Grand Canyon region (fig. P12). This sandstone forms the massive 

cliff that underlies the platform known as the Esplanade.

The lower half of the main sandstone body represented 

by facies B of the Esplanade Sandstone projects westward 

as tongues into carbonate rocks, facies E and H, of the 

Pakoon (fig. P12). These Pakoon facies are well developed 

along the Grand Wash Cliffs in extreme western Grand 

Canyon (measured sees. 27, 28, and 30), at Iceberg Canyon (sec. 31) and at Guano Cave (sec. 26) Farther east, at 

Andrus Canyon (sec. 24), Separation Canyon (sec. 34) and 

elsewhere, they occur only as tongues within thick sandstone units of the Esplanade.

Other distinctive facies of the Esplanade Sandstone and 

Pakoon Limestone are the bedded gypsum deposits that 

form a large lens (facies J) within massive sandstones in the 

northwestern part of the area, from Toroweap Valley (sec. 

21) to Andrus Canyon (sec. 24), and the dolomitic sandstone of facies I in the lower part of the formation in the 

same general area. Facies A, composed largely of reddishbrown to pale-reddish-brown mudstone and siltstone is 

distributed largely in the eastern Grand Canyon area, partly as the basal slope-forming unit of the Esplanade and 

partly interbedded with massive sandstones of facies B, 

especially in the upper part of the formation.

Facies A—Red argillaceous 

mudstone

This facies consists of fine-grained detrital sediment, including both siltstone (composed largely of silt-size particles) and mudstone (defined here as a mixture of clay-size 

material and silt grains). Mostly this facies is argillaceous 

but, in some places, it is also calcareous. The color of the 

mudstone is reddish brown, ranging from pale to moderate 

to dark; where relatively pure, the siltstone tends to be reddish orange.
356 THE SUPAI GROUP OF GRAND CANYON

SECTIONS NORTH OF 

GRAND CANYON

SECTIONS SOUTH OF 

GRAND CANYON

FEET

300-

200-

100-

10 20 30 40 MILES

A Red argillaceous mudstone

Calcareous cross-stratified sandstone

Bioclastic limestone with matrix (packstone and 

wackestone). Occurs with facies H in western 

sections

H Dolostone and calcitic dolostone, interbedded 

with facies E bioclastic limestone (packstone)

Dolomitic sandstone 

Bedded gypsum 

Conglomerate

Dashed line indicates pre-Hermit Shale erosion 

channel tops

FIGURE P12.—Fence diagrams of east-to-west sections showing distribution of facies of the Esplanade Sandstone and Pakoon Limestone (McNair, 

1951) of Grand Canyon region, Arizona. Number at base of each vertical line refers to measures section locality as shown on figure A1
PETROGRAPHY 357

Mudstone and siltstone of facies A of the Esplanade 

commonly are structureless, but in some places consist of 

thin flat beds and elsewhere have irregular wavy bedding. 

Throughout the Grand Canyon region this facies forms the 

basal slope unit, 40-100 ft thick, except in the far western 

area where the rock consists largely of limestone and forms 

the basal slope unit of the Pakoon. Thin units of facies A 

occur also in the upper cliff-slope unit of the Esplanade, 

alternating with thick cross-stratified sandstones of facies 

B at Twentynine Mile Canyon, Bunker Trail, and elsewhere in the northeastern and eastern parts of the region.

Minor structures, including mud pellets, rain pits, 

shrinkage cracks, and asymmetrical ripple marks, also 

fragments of land plants, especially the coniferous genus 

Walchia and the algae Rivularities sp., give some suggestions concerning the depositional environment. Apparently facies A, at least locally, represents continental 

sedimentation.

From the standpoint of geographic distribution, most of 

the finest detritus—the mudstones—occur in eastern 

Grand Canyon and to the northeast in Marble Canyon. 

They form most of the basal slope unit, 40-100 ft thick, 

above the basal conglomerate of the Esplanade and below 

the main sandstone cliff. They also occur in the upper part 

of the main cliff unit, especially in Marble Canyon, where 

thin units alternate with thick sandstone beds. Some 

mudstone beds extend westward into central Grand Canyon at Toroweap and Prospect Valley sections (21, 20), 

but farther west the stratigraphic position in the basal 

Esplanade slope unit is occupied by friable, very fine 

grained sandstones.

Facies B—Peloidal 

cross-stratified sandstone

This facies constitutes a major part of the Esplanade 

Sandstone and is by far the most widespread and characteristic rock in the formation. It consists of calcareous 

cross-stratified sandstone (fig. P13A) that is largely a 

moderate reddish orange, but ranges into weak orange and 

very pale orange according to the rock color chart (Goddard, 1948). The sandstone weathers to a resistant cliff 

supporting the prominent bench or platform known as the 

Esplanade in the upper walls of Grand Canyon.

The sandstone of facies B of the Esplanade is predominantly very fine grained as determined by many mechanical analyses and by a large number of thin-section measurements. In a very few places the mean grain size is fine 

and in some other localities a high percentage of silt is present. In most places the sorting is good. Quartz grains are 

rounded to subrounded except where they are of silt size; 

those are mostly angular to subangular.

Although facies B is composed dominantly of quartz 

sand, it includes scattered grains of bioclastic calcium carbonate in most measured sections. Especially numerous 

among the bioclasts are foraminifers and crinoidal debris. 

With a calcareous cement, the rock typically contains 

10-50 percent calcite so is classed as a calcareous to very 

calcareous sandstone; similar rock with a dolomitic cement, occurring in the lower half of the formation from 

Tuckup Canyon (sec. 18) to Andrus Canyon (sec. 24), is 

designated as facies I.

Facies E-H—Bioclastic limestone 

and calcitic dolostone

Bioclastic limestone typical of facies E and dolostone or 

calcitic dolostone of facies H are interbedded and are so 

closely associated in some places that they are shown as 

combined in parts of figure P12. They occur together, 

especially in southwestern parts of the Grand Canyon 

region where they form the lower part of the Pakoon Limestone and tongues of the Pakoon within the Esplanade. 

Generally, limestones of facies E-H are easily distinguished 

from those of underlying formations in the Supai Group 

by (1) a lack of accretal grains, (2) a relatively small 

number of peloidal grains, and (3) a predominance of 

skeletal grains.

Skeletal grains of facies E mostly are contained in a 

matrix of carbonate mud. In some places they are grainsupported (packstone), but elsewhere are mud-supported 

(wackestone). The grains commonly are well sorted and 

rounded and presumably were formed in an environment 

of high energy, directly above gravels of the basal conglomerate of the Esplanade that mark the beginning of a 

major transgression. Especially abundant among the grains 

are fragments of pelmatozoans.

The dolostone and calcitic dolostone of facies H, which 

are intimately associated with bioclastic limestone, are thin 

bedded and abundant in the southwestern Grand Canyon 

area adjacent to the Cordilleran geosyncline.

Facies I—Dolomitic sandstone

The lower part of the Esplanade Sandstone in northwestern Grand Canyon resembles the sandstone of facies B 

except that the cement is dolomite, rather than calcite. 

This dolomitic sandstone is referred to as facies I (fig. P12). 

It is typically developed at Tuckup Canyon, Whitmore 

Wash, Andrus Canyon (sees. 18, 22, 24), and other nearby 

sections.

The quartz sand grains of facies I seem in some places to 

be supported by recrystallized dolomite, suggesting that 

the sand may have contained a significant amount of bioclastic material prior to emplacement of the dolomite. As 

in the correlatable calcite-cemented sandstones to the east 

and south, the quartz grains mostly are very fine grained, 

well sorted and subangular; likewise the sandstone is
358 THE SUPAI GROUP OF GRAND CANYON

FIGURE P13.—Photomicrographs (x 10) of fades in the Esplanade 

Sandstone and Pakoon Limestone (McNair, 1951). A, Very fine 

grained, cross-stratified sandstone of facies B, containing angular to 

subangular quartz grains, peloids of limestone, foraminiferal debris 

and micritic matrix; from main cliff of Esplanade Sandstone, Thunder 

River Trail, sec. 12. B, Silty carbonate mudstone of facies C (insoluble residue 12.5 percent); from basal slope unit, Esplanade Sand-

- stone, Twentynine Mile Canyon, sec. 2. C, Bioclastic limestone inhighly cross-stratified. Small foraminifers, numerous in 

some related, adjacent facies, are uncommon in this sand. 

At Parashant Canyon (sec. 23) and Andrus Canyon (sec. 

24) measured sections, the dolomitic sandstone of facies I 

includes a relatively sparse component of bimodal, wellrounded, medium- to coarse-grained sand (fig. P13D). 

Abundant particles of chert occur in this sand.

"•Jr'fe? • & Ir - *.-r.*f. < « o*t» *rv«-«»'i:L^P^-*ri;i sj*«-r!lP'>Ti«\:^ ^^%' *--.4t-*.icyt ;

*•.; fe 'i^uto ^•awJ-i'-Fx.ik^^.w-. -X-'-ftLJ- iifaK* Tit-- t .\iBisiK*,4,J*«

eluding fragments of bryozoans, pelmatozoans, and pelecypods of 

facies E mixed with cryptocrystalline dolomitic limestone of facies H; 

insoluble residue, 12.6 percent; from Iceberg Canyon, lower part of 

cliff unit, Pakoon Limestone. D, Dolomitic sandstone of facies I composed of medium- to coarse-grained sand of well-rounded quartz, 

chert, and pelmatozoan particles, and very fine grained subangular 

sand grains with dolomite cement; from upper part of main cliff, 

Esplanade Sandstone, Parashant Canyon, sec. 23.

Facies J—Bedded gypsum

Bedded gypsum of facies J (fig. P12) extends across a 

considerable area in west-central Grand Canyon—from 

Toroweap Valley (sec. 21) to Andrus Canyon (sec. 24). It 

occurs between massive units of cross-stratified sandstone 

of facies B. Based on stratigraphic relations, these gypsum
PETROGRAPHY 359

deposits seem to have been accumulated in an area landward of the Cordilleran seaway and separated from it by 

extensive cross-stratified sands of the upper cliff-slope unit 

of the Esplanade. Paleogeographic considerations indicate 

that they represent accumulations in lagoons bordering the 

main seaway to the west and the marine embayment to the 

south (fig. D8).

REFERENCES CITED

Dunham, R. ]., 1962, Classification of carbonate rocks according to 

depositional texture, in W. E. Ham, ed., Classification of carbonate 

rocks—A symposium: American Association of Petroleum Geologists Memoir 1, p. 108-121.

____1969, Early vadose silt in Townsend mound (reef), New Mexico, in 

G. M. Friedman, ed., Depositional environments in carbonate 

rocks—A symposium: Society of Economic Paleontologists and Mineralogists Special Publication 14, p. 139-181.

Folk, R. L., 1962, Spectral subdivision of limestone types, in W. E. Ham, 

ed., Classification of carbonate rocks—A symposium: American 

Association of Petroleum Geologists Memoir 1, p. 62-84.

____1973, Carbonate petrography in the post-Sorbian age, in R. N. 

Ginsburg, ed., Evolving concepts in sedimentology: The Johns Hopkins University Studies in Geology, no. 21, p. 118-158.

Folk, R. L., and Land, L. S., 1975, Mg/Ca ratio and salinity; Two controls over crystallization of dolomite: American Association of 

Petroleum Geologists Bulletin, v. 59, no. 1, p. 60-68.

Goddard, E. N., chm., and others, 1948, Rock-color chart: National 

Research Council (reprinted by the Geological Society of America, 

1951,1970), 6 p.

McKee, E. D., and Gutschick, R. C., 1969, History of the Redwall Limestone of northern Arizona: Geological Society of America Memoir 

114, 726 p.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

Sander, Bruno, 1951, Contributions to the study of depositional fabrics; 

rhythmically deposited Triassic limestones and dolomites: Tulsa, 

Okla., American Association of Petroleum Geologists, 207 p.

Toomey, D. F., 1969, The biota of the Pennsylvanian (Virgilian) Leavenworth Limestone, midcontinent region—Part 2, Distribution of 

algae: Journal of Paleontology, v. 43, no. 6, p. 1313-1330.

Twenhofel, W. H., 1919, Pre-Cambrian and Carboniferous algal deposits: American Journal of Science, 4th Ser., v. 48, p. 339-352.

THE SUPAI GROUP OF GRAND CANYON

STABLE ISOTOPE ANALYSES

Chapter Q 

By EDWIN D. McKEE

Contents

Isotopic analyses ...........

Watahomigi Formation .

Manakacha Formation ..

Wescogame Formation .

Summary of isotopic data 

References cited ...........

Page

363

363

364

364

364

364

361
362 THE SUPAI GROUP OF GRAND CANYON

Table

Page

TABLE Q1. Stable isotope analyses of limestone from Supai Group, Kaibab Trail, south ............... 363
STABLE ISOTOPE ANALYSES 363

ISOTOPIC ANALYSES

Stable isotope abundance measurements were made for 

limestones from a selected suite of samples representing the 

lower three formations of the Supai Group along the 

Kaibab Trail, south, in eastern Grand Canyon (table Ql). 

For this project both oxygen and carbon isotope analyses 

were kindly made by J. R. O'Neil in the Menlo Park laboratories of the U.S. Geological Survey. The objective in 

making these measurements was to obtain, if possible, 

evidence pertaining to the environments of deposition as 

recorded by various carbonate rocks within the Supai 

Group. Such evidence should supplement data based on 

faunal analysis, cross-strata studies, clay-mineral investigations and other environmental indicators.

The premise upon which isotopic data are considered 

useful in determining environmental conditions is that 

marine carbonate rocks are normally richer in 13C than are 

freshwater types. The first study to promote this concept 

was by Clayton and Degens (1959) who reported in their 

table 1 a mean 613C of -1.54 for marine rocks and of - 6.66 

for freshwater types. A later study by Keith and Weber 

(1964) based on analyses of 500 marine and nonmarine 

limestones showed mean 613C values of +0.56 for marine 

rocks and -4.93 for those of freshwater origin. These 

results support the view that nonmarine types have lower 

613C values than marine limestones.

Studies by Keith, Anderson, and Eichler (1964) and by 

Weber (1964) lend support to this concept that marine 

limestones are enriched in 13C relative to nonmarine limestones. A comparison of recent marine and nonmarine 

mollusk shells has been made by Keith, Anderson, and 

Eichler (1964); analyses of freshwater carbonate rocks of 

the Flagstaff Limestone (Paleocene and Eocene) of Utah are 

described by Weber (1964). Not all continental deposits are 

freshwater, however, and the recognition of brackishwater and hypersaline environments must also be considered in the interpretation of isotopic analyses. In a study 

of hypersaline lake deposits of the Lake Bonneville area by 

Degens and Epstein (1964), for instance, relatively high 

613C values ranging from +0.12 to +4.50 are recorded.

Although both 618O and 613C were measured in 

attempting to interpret formation conditions of the Supai 

carbonate rocks, the 618O values that range from -4.5 to 

- 6.2 in the samples analyzed were not used because, as indicated by Keith and Weber (1964, p. 1787), compositions 

"exhibit a progressive increase in average oxygen-18 content from oldest to youngest age group," (for example, 

Cambrian -9.7 to Quaternary -1.2 permil). In contrast, 

"no great change has occurred in the carbon isotopic composition of marine bicarbonate over geologic time," according to the same investigators.

Watahomigi Formation

Isotopic analyses of two limestone samples from the 

lower or Morrowan part of the Watahomigi (table Ql) are 

interpreted as indicating a marine environment. The 613C 

value of -0.8 for sample KS-1, an aphanitic limestone 

from near the base, is well within the normal range (0.0± 3) 

for marine limestones. Sample KS-2 from near the top of 

the Morrowan limestones has a 613C value of - 3.4, which 

is near the upper limit for Carboniferous marine limestones 

as recorded by Keith and Weber (1964, p. 1805, 1806).

Supporting evidence of marine origin is a brachiopod 

fauna in the same unit at National and Tuckup Canyons to 

the west. Clay minerals from this formation include some 

kaolinite in eastern Grand Canyon that is considered nonmarine, but they also include illite and corrensite, which 

are interpreted as representing deposits laid down during 

periodic marine incursions. Probably the limestones under 

consideration reflect the same environmental control.

TABLE Ql.—Stable isotope analyses of limestone from Supai Group, Kaibab Trail, south

[Analyses by |. R. O'Neil. 6-values are given in per mil relative to the PDB standard]

Formation

Do. ............

Do. ............

Do. ............

Do. ............

Do. ............

Do. ............

Age

do. ............

do. ............

do. ............

do. ............

do. ............

Sample

No.

KS-1

KS-2

KS-3

KS-7

KS-8

KS-11

K-13

K-14

K-14a

6 13C

-0.8

-3.4

-4.7

-4.6

-3.8

-5.4

-4.3

-5.0

-5.4

6 18 O

-5.0

-5.9

-6.2

-6.2

-5.6

-4.6

-4.8

-4.5

-5.3

Type of carbonate rock

Limestone bed, top of sandstones.

Do.

Do.
364 THE SUPAI GROUP OF GRAND CANYON

Manakacha Formation

Isotopic data for the Manakacha (table Ql) are compatible with the idea that these rocks were deposited in an environment in which the water was less saline than normal 

marine water and that some carbon of organic origin was 

incorporated in the limestone. Samples KS-7 and KS-8 

(table Ql) are from limestone lenses within thick beds of 

highly cross-stratified, calcareous sandstone interpreted as 

marine.

Because the limestone lenses and associated clays of the 

Manakacha clearly did not form under the high-energy 

conditions represented by the sandstones, they may well 

have been deposited in brackish-water environments 

developed between times of marine sand accumulation. 

Thus, the 613C values of - 4.6 and - 3.8 for the Manakacha 

limestones possibly explain an isotopic composition that is 

generally intermediate in heaviness between the freshwater 

Pennsylvanian analyses and the marine Pennsylvanian 

analyses recorded by Keith and Weber (1964, p. 1805, 

1806).

Associated clay minerals in eastern Grand Canyon 

include much kaolinite, considered nonmarine, but are 

largely marine types, especially illite, to the west. Probably marine conditions merged into nonmarine in the 

eastern area where the limestones under discussion were 

deposited.

Wescogame Formation

Limestones of the Wescogame (table Ql) have 613C 

values ranging between —4.3 and —5.4. These 513C values 

are close to the value of -4.93 recorded by Keith and 

Weber (1964, p. 1787) for freshwater limestones and the 

-6.66 recorded by Clayton and Degens (1959, p. 891) for 

"non-marine carbonate rocks." The interpretation of a 

freshwater environment for these thin limestone beds and 

lenses that occur among red beds of the Wescogame in 

eastern Grand Canyon is in keeping with evidence from 

other sources. In the abundant sandstones of the Wescogame, reptilian tracks occur, and distinctive cross-strata of 

types common to braided streams are present. Furthermore, the common association of kaolinite considered 

diagnostic of a freshwater environment also supports the 

interpretation of fluvial conditions.

Summary of isotopic data

Summarizing conclusions concerning the isotopic composition of Supai Group limestones from the Kaibab Trail, 

south, the values obtained seem to form three general 

groups, representing each of the three formations considered. The oldest formation, the Watahomigi, shows 

values favorable to a marine interpretation. The second 

formation or Manakacha, has intermediate values considered possibly to represent brackish-water environments. The youngest or Wescogame Formation is interpreted as including freshwater limestones.

As suggested by the recent work of Hoefs (1973, p. 98), 

"isotopic criteria should be regarded as additional 

parameters, supplemental to paleontologic and petrographic criteria, for determining the depositional environments." Limitations in the application of isotope data in 

interpreting depositional environments are stated by Hoefs 

(1973, p. 98) as follows: "isotopic composition * * * depends not only on the environment at the time of deposition, but also on isotopic exchange processes since deposition." It therefore must be demonstrated "that carbonate in 

sediments is of sedimentary origin and not contaminated 

by either detrital or post sedimentary processes."

REFERENCES CITED

Clayton, R. N., and Degens, E. T., 1959, Use of carbon isotope analyses 

of carbonates for differentiating freshwater and marine sediments: 

American Association of Petroleum Geologists Bulletin, v. 43, no. 4, 

p.890-897.

Degens, E. T., and Epstein, Samuel, 1964, Oxygen and carbon isotope 

ratios in coexisting calcites and dolomites from recent and ancient 

sediments: Geochimica et Cosmochimica Acta, v. 28, p. 23-44.

Hoefs, Jochen, 1973, Stable isotope geochemistry: New York, Heidelberg, Berlin, Springer-Verlag, 140 p.

Keith, M. L., and Weber, J. N., 1964, Carbon and oxygen isotopic composition of selected limestones and fossils: Geochimica et 

Cosmochimica Acta, v. 28, p. 1787-1816.

Keith, M. L., Anderson, G. M., and Eichler, R., 1964, Carbon and oxygen isotopic composition of mollusk shells from marine and freshwater environments: Geochimica et Cosmochimica Acta, v. 28, p. 

1757-1786.

Weber, J. N., 1964, Carbon-oxygen isotopic composition of Flagstaff 

carbonate rocks and its bearing on the history of Paleocene-Eocene 

Lake Flagstaff of central Utah: Geochimica et Cosmochimica Acta, 

v. 28, p. 1219-1242.
THE SUPAI GROUP OF GRAND CANYON

APHANITIC SILICA ROCK

Chapter R 

By EDWIN D. McKEE

Contents

Principal varieties ..................................

Terminology for reddish-brown cryptocrystalline silica rock 

Distribution of jasper ....................... .......

Petrology of red-brown jasper ........................

Origin of jasper ....................................

Age of jasper ......................................

References cited ...................................

Page

367

367

367

369

372

374

374

365
366 THE SUPAI GROUP OF GRAND CANYON

Illustrations

FIGURE R1. Photographs of deposits of cryptocrystalline silica ................................... 368

R2. Color photograph of typical banded jasper in limestone, Manakacha Formation, Parashant Canyon .............................................................. 369

R3. Photographs showing concentrations of jasper ..................................... 370

R4. Diagrams showing stratigraphic and geographic distribution of jasper deposits,

Watahomigi Formation ...................................................... 371

R5. Diagrams showing stratigraphic and geographic distribution of jasper deposits,

Manakacha Formation ....................................................... 372

R6. Photomicrographs of deep-red jasper core of calcareous siltstone nodule ................ 373

R7. Electron micrograph of red-brown jasper from limestone bed, Manakacha Formation ...... 373

Tables

TABLE R1. Analysis of form in jasper bodies ................................................. 367

R2. Analysis of enclosing rocks for jasper bodies ....................................... 368

R3. Analysis of bedding-types containing jasper bodies .................................. 369

R4. Semiquantitative spectrographic analysis of jasperoid sample .......................... 371

R5. Recorded localities of jasper pebbles ............................................. 373
APHANITIC SILICA ROCK 367

PRINCIPAL VARIETIES

Cryptocrystalline silica rock of several varieties occurs 

in various parts of the Supai Group, but is especially common in the Watahomigi and Manakacha Formations. 

Some of it is in the form of siliceous crusts that form highly 

irregular, concentric, or other striking patterns (fig. RID, 

E) that suggest, at least superficially, some reeflike, stromatolitic structures. This type commonly is porous, dull 

buff or pale gray, but weathers to hard, dark-brown or 

black surfaces that etch out in relief. Such stromatolitic 

structures are common near the base of the Watahomigi 

near the Kaibab Trail of eastern Grand Canyon and about 

midway in the lower unit of the Manakacha Formation 

along the walls of Snap Canyon in the west.

A second variety of cryptocrystalline silica rock is translucent and is white, yellow, pink, or other light color; it 

has commonly been referred to as chert (Walcott, 1880; 

Noble, 1922, p. 60, 61). This variety forms thin anastomosing layers in massive carbonate beds near the base of 

the Watahomigi Formation (fig. RM), or irregular bands 

of concretions (fig. R1C) in the Pakoon Limestone 

(McNair, 1951). Much of this chert seems to be chalcedonic.

By far the most common variety of cryptocrystalline 

silica in the Supai Group is a dense, reddish-brown type 

that occurs throughout the two lower formations in sheetlike and concretionary forms similar to those of the chert, 

and also in other forms described later. This form is referred to as jasper and is very consistent in color and 

aphanitic texture (fig. R2). The color range as determined 

on the rock-color chart (Goddard, 1948) is between moderate reddish brown and dark reddish brown.

TERMINOLOGY FOR 

REDDISH-BROWN 

CRYPTOCRYSTALLINE 

SILICA ROCK

The reddish-brown, opaque variety of cryptocrystalline 

silica that is widespread in the Supai Group throughout the 

Grand Canyon region is difficult to classify. It occurs 

largely as an extremely fine grained and relatively 

homogenous rock and has an aphanitic, almost glassy texture—characteristics that fit the definitions of numerous 

cryptocrystalline silica rocks. The term "jasperoid," introduced by Spurr (1898), recently has been discussed by 

Levering (1972, p. 3), who stated that "jasperoids are composed predominantly of silica which in most places is in the 

form of aphanitic to fine-grained quartz and forms by 

replacement of the enclosing rock." These features seem to 

apply to many of the Supai silica rocks.

In his detailed treatment of this rock type, Levering 

restricts the term jasperoid to "an epigenetic siliceous 

replacement of a previously lithified host rock" and excludes what he considers syngenetic or diagenetic forms of 

silica, such as primary chert and novaculite. The following 

criteria, according to Levering (1972, p. 6), serve to 

distinguish jasperoid from bedded chert, which it closely 

resembles: "(1) jasperoid beds are localized in a relatively 

small area in contrast to the broad regional distribution of 

bedded cherts, and (2) jasperoid layers commonly grade 

laterally into larger masses with evident structural 

control." Although a genesis by replacement may apply to 

most, if not all, of the reddish-brown silica deposits of the 

Supai, the matters of localized distribution and of regional 

structure control do not.

In this publication, the term "jasper" is used in referring 

to the reddish-brown silica rock that is the dominant 

cryptocrystalline form in irregular layers or sheets, lenses, 

and other forms throughout much of the Supai Group. In 

texture, color, and genesis this rock seems to fit the term, 

as used by most geologists, better than any other.

DISTRIBUTION OF JASPER

Dark reddish-brown, cryptocrystalline silica, referred to 

as jasper, is a common and characteristic lithologic constituent of the Watahomigi and Manakacha Formations. It 

occurs mostly as thin, extremely uneven layers or "bands" 

within massive beds of carbonate rock, but it also forms 

lenses, irregular masses, concretions, and crosscutting 

"veins" (fig. R3; table Rl). Aphanitic limestone is the most

TABLE Rl.—Analysis of form in jasper depositional bodies. Figures 

refer to number of rock units containing each form in measured 

sections under study

Formation

Manakacha . . .

Watahomigi . .

Uneven layers

("bands")

69

58

Lenses

39

25

Nodular

concretions

9

7

Crosscut

veins

2

5

Irregular

masses

1

1

common host rock, although granular limestone, silty or 

sandy limestone, and dolomite, as well as some detrital 

rocks such as calcareous mudstone, calcareous siltstone, 

and calcareous sandstone, are also jasper-bearing (table 

R2). Jasper deposits occur in both flat-bedded and crossstratified rock units, but more commonly are in thick 

massive beds than in thin ones (table R3). Jasper deposits 

are relatively uncommon in cross-stratified units, and, in 

sandstone, seem to be restricted to those beds that are very 

calcareous.

Charts of jasper distribution—both stratigraphic and
368 THE SUPAI GROUP OF GRAND CANYON

w:y^ ip«W- .-*. '^2^""~- y^^fc *-rrC ^s&^Hp

- , f T——V •*- _——^i'-T"- « .t.. ' i. ,

•<—#•- -- -^^g*- -. -**- V,^*^:

,•- «gf*r - A^j-

'~*"*S**\ •

"*'**' *^! ^fe.*£r^l

rj#r' 'J-, - -c" ';1 »*«A*TM^i.*^^.^ji.;:^c *' !T^'A4^^.

FIGURE R1.—Deposits of cryptocrystalline silica in carbonate rocks of 

Supai Group and Pakoon Limestone (McNair, 1951), Grand Canyon 

region, Arizona. A, Irregular layers or "bands" of white chert in 

thick-bedded limestone. Chert follows planes of dipping cross-strata 

in right center. Near base of Watahomigi Formation near Bass Trail. 

8, Layers of red jasper between foreset beds of sandy limestone with 

large-scale tabular-planar structure, Wescogame Formation, Pigeon 

Wash. C, Concretions of reddish-brown chert containing concentrations of crinoids in thick-bedded aphanitic limestone of Pakoon 

Limestone, Iceberg Canyon. D, E, Crust or shells of chertlike, cryptocrystalline silica forming irregular and inconsistent structure pattern in limestone near base of Watahomigi Formation, Kaibab Trail; 

scale is in centimeters. Photographs by L. M. Hinchliffe.

TABLE R2.—Analysis of enclosing rocks for depositional bodies of jasper. Figures 

refer to number of rock units in measured sections under study that represent 

each rock type

Formation Aphanitic Granular

Silty, 

sandy

Dolostone, Mudstone, Sandstone, Siltstone, 

calcareous calcareous fine-very calcareous 

fine

Manakacha . . 

Watahomigi .

49

45

26

30

31

20

11

2

10

3
APHANITIC SILICA ROCK 369

FIGURE R2.—Typical "banded" jasper in limestone, Manakacha Formation, Parashant Canyon, Ariz. Natural size. Illustrates dark reddishbrown color that distinguishes it from all other silica rock in the Supai 

Croup.

geographic—in the Grand Canyon region (figs. R4, R5) 

show that nearly all of the jasper deposits of the Supai 

Group are in the lower two formations, the Watahomigi 

and the Manakacha. A probable reason for this stratigraphic control is the relative scarcity of limestone strata in 

the Wescogame Formation and Esplanade Sandstone. 

Some cross-stratified sets in limestone and calcareous 

sandstone in the Wescogame of far western Grand Canyon 

(fig. RIB) are jasper-bearing units, but outcrops of the 

Wescogame in most other areas are barren of jasper. 

Distribution of jasper in the two lower formations of the

TABLE R3.—Analysis of bedding-types containing jasper depositional 

bodies. Figures refer to number of rock units in measured sections 

under study that contain jasper deposits

Flat-bedded

Formation

Manakacha

Watahomigi ....

Thin

7

7

Thick

113

115

Cross-stratified

Sandstone

6

0

Limestone

8

4

Supai Group seems to be dependent on the presence of carbonate rocks within a stratigraphic section. In the Watahomigi Formation, for instance, concentrations of jasper 

everywhere are greatest in the middle cliff or limestone 

unit, and generally are least common in the lower slope or 

red mudstone unit where limestone is relatively scarce (fig. 

R4). In the Manakacha Formation, jasper concentrations 

are absent in the upper (slope) unit of nearly all sections of 

eastern Grand Canyon where sandstone, rather than limestone, is dominant. In general, jasper is characteristic of 

the lower (cliff) unit of the Manakacha and seems to rise 

stratigraphically in a southwesterly direction (fig. R5) 

where the lower unit is thicker and carbonate rock is an increasingly greater component of the formation.

PETROLOGY OF 

RED-BROWN JASPER

During the present investigation of the Supai Group, 

samples considered typical of the red-brown jasper were 

referred for examination to T. G. Levering of the U.S. 

Geological Survey, who was at that time making a detailed 

study of jasperoids in the United States (Levering, 1972). 

Two selected samples were examined in thin section—one 

was the common "banded" variety in limestone; the other 

was a jasper core within concentrically laminated nodular 

limestone. A semiquantitative spectrographic analysis was 

made of the banded type.

The banded jasper examined by Levering was described 

by him from hand specimen as a dense, aphanitic paleorange to reddish-orange rock, forming irregular lenses 

elongated parallel to the bedding in a gray, fine-grained, 

irregularly banded limestone. In thin section, the SiO2 

in this specimen is described (T. G. Levering, written 

commun., 1971) as consisting "of interlocking, but more or 

less equant quartz grains averaging about 0.05 mm and 

ranging from 0.02 to 0.1 mm and containing abundant inclusions of fine-grained calcite" (figs. R6A, B). He further 

stated that "both texture and grain size of this quartz are 

more suggestive of jasperoid than of chert."

In the spectrographic analysis (table R4) made of the 

banded jasper, most of the elements seem to be represented 

in amounts expectable for jasperoid. Comparing these with 

data in figure 33 of Levering (1972, p. 32) that shows comparisons between cherts and jasperoids, in distribution of 

elements, it is evident that the Supai specimen is normal 

jasperoid in most respects. The large amount of SiO2 is expectable, and the high calcite content probably reflects the 

inclusion of some carbonate matrix. Only the copper 

seems slightly anomalous for it is well above the median 

figure obtained by Levering (written commun., 1977), for 

both primary and supergene chert (0.0015 percent), and is
370 THE SUPAI GROUP OF GRAND CANYON

/'

even above that for primary jasper (0.0030 percent). It is 

not above his figure for supergene jasper (0.017).

Examination of the red jasper core in a silty limestone 

nodule enabled Lovering to furnish the following petrographic description:

The red jasper consists of heterogeneous quartz grains with 'jigsaw puzzle' 

texture and abrupt variations in grain size from 0.1 mm to 0.01 mm with 

small masses of penecontemporaneous flamboyant chalcedony. 

Numerous inclusions of irregular red hematite grains, showing about the 

same size range as the quartz, also inclusions of calcite aggregates (0.1-0.2

*^~*4

FIGURE R3.—Concentrations of jasper in carbonate rocks of the Supai 

Group, Grand Canyon region, Arizona. A, Irregular layers or 

"bands" of deep-red jasper alternating with layers of light-gray 

limestone in massive bed. Individual jasper layers are mostly 2-4 in. 

thick. Massive cliff unit of Manakacha Formation. Toroweap Valley 

measured section 8, Jasper layers following foreset parting plane and 

upper bounding plane of cross-stratified sandy limestone in cliff unit 

of Wescogame Formation, south of Grand Gulch Mine near Pigeon 

Wash. C, Irregular layers and lenses of jasper in laminated pink sandy limestone of Wescogame cliff unit, Picacho Butte. D, Jasper lenses 

and irregular masses in massive aphanitic limestone of Manakacha 

Formation, Parashant Canyon. £, Horizontal surface of concentric 

layers of jasper in massive bed of aphanitic limestone, base of 

Manakacha Formation, S B Canyon. F, Mound of roughly elliptical 

thin layers of jasper embedded in sandy limestone of Watahomigi 

Formation, Parashant Canyon.
APHANITIC SILICA ROCK 371

R

C,B

L

L

B

L

B B 

B

-r\^^\^

L

B 

B B

\ A

B

B,L 

B

R

jfVj

- ———— L

: B B 'L' N

.

L

N,L,B

B

\

B

UB

^ ————

B B,L 

B

UB N

B

L N '

L

14 30 30a 28 27 25

B

el

N,B

B

UC

B

C,B

__ __ |

L

B B 

B

~~~ " B,L

B 

B

£

B,L L;

I B,L

22 15 14 10 83

c

B

UB

L

^^^^^ R __

B 

B

IB

B

B 

B

B 

N,B

B

B

C,L

^__^

B

B

/

L

\, C

L B

B

-

27 24 23 22 21 18 17 16 11

D

31

UB - UN

D'

26 34 35 19

FET 

300

200

— 100

EXPLANATION 

B Beds or "bands" 

L Lenses 

C Cross-cut veins 

N Nodular concretions

20 30 MILES

FIGURE R4.—Stratigraphic and geographic distribution of jasper deposits in Watahomigi Formation along principal lines of sections A-A' to 

F-F' as shown in figure A1; numbers are those of measured sections shown on same figure.

mm) that look like calcite in the host rock, are present. The jasper ground 

mass is cut by small branching veinlets of fibrous chalcedony. Pigmentation of ferric oxide is extremely fine grained (less than 0.005 mm in 

diameter).

Electron microscope examination of jasper fracture surfaces, using the replica technique, was made by Kenneth 

Gardner in connection with this study. Unpolished surfaces of freshly fractured rock showed polyhedral blocks 

with smooth faces and sharp definition (fig. R7). The 

blocks appeared nearly equal in size and had slightly 

curved surfaces. Probably the form was governed by the 

spacing of initial centers of crystallization as described by 

Folk and Weaver (1952, p. 507) who postulated that 

replacement was favored by "close spacing, resulting in the 

formation of microcrystalline quartz."

TABLE R4.— Semiquantitative spectrographic analysis of aphanitic, red 

jasperoid sample from limestone of the Manakacha Formation at 

Pigeon Wash, Arizona

[Data from T. C. Levering]

Element Percent Element

'Probably includes some carbonate matrix. 

2Slightly anomalous.

Percent

Si ........

Al

Fe ........

Mg .......

Ca .......

Na .......

Ti ........

>10

.3

.15

.07

H

.05

.007

Mn ........

Ba .........

Cr .........

Cu ........

Sr .........

Zr .........

...... 0.01

...... .0015

...... .0007

...... 2 .01

...... .003

...... .001
372 THE SUPAI GROUP OF GRAND CANYON

B : 

B,C 

14

A'

B

B

B

UN 

B

L 

L B,L

B

B

B

B,N B

B ______ L

B

L

N 

L-L

—— — ——

B

D B

L L B'L

B

B

B

31 30b 28 27 25

B

L

B ^^^^

L,B

:N,B L' B

: B B

L

B,C

L B

B,C

B

L,B

22

B'

15 14 10

B B

F

L

-BL

B 

L 

LL L-

\

B

V 

F V

B 

N,B B 

B B 

B

B 

F L'B 

B B 

B

X

B 

B 

L,B B

N

L,B 

L 

B-L

c

L 

L B.

27 24 23 22 21 18 17 16 12

FEET 

-300

-200

100

EXPLANATION 

B Bed or"band" 

L Lenses 

C Cross-cut veins 

N Nodular concretions 

F Foreset planes

20 30 MILES

FIGURE R5.—Stratigraphic and geographic distribution of jasper deposits in Manakacha Formation along principal lines of sections A-A' to F-F' 

as shown in figure A1; numbers are those of measured sections shown on same figure.

ORIGIN OF JASPER

The dark-red-brown jasper of the Supai Group clearly is 

a product of replacement for, although in most places it occurs as nearly horizontal layers that are parallel to bedding 

planes or it follows foreset surfaces of cross-strata, many 

examples of crosscutting veins, also are recorded. Furthermore, at a number of localities, such as in the Watahomigi 

Formation at Pica, Arizona (Hughes, 1952), examples of 

brachiopods and other marine fossils that are preserved in 

the form of jasper indicate replacement. Abundant petrographic evidence showing replacement also is available.

A specimen from a jasper lens in limestone of the

Manakacha Formation at Pigeon Wash showed in thin section that the jasper was younger than the recrystallized 

calcite at its boundary, according to T. G. Levering (written commun., 1971). "Thus, the sequence of events seems 

to be (1) recrystallization of limestone, (2) chalcedony 

locally replacing limestone, goethite and hematite, (3) 

quartz, (4) late calcite."

The time of quartz replacement can be determined within certain limits for jasper in the formations of the Supai 

Group. Probably all quartz replacement took place during 

Pennsylvanian time. Some replacement was between Morrowan time and the beginning of Atokan deposition, for 

the conglomerate at the base of the Atokan in the 

Watahomigi Formation is, in places, replete with jasper
APHANITIC SILICA ROCK 373

FIGURE R6.—Photomicrographs of deep-red jasper core of calcareous 

siltstone nodule. Manakacha Formation, Grand Gulch Wash, Ariz. 

Prepared by T. G. Levering. A, Core of jasper illustrating roughly 

equant quartz grains containing abundant inclusions of fine-grained 

calcite. Texture and grain size suggestive of jasperoid. B, Center of 

jasper core shown in A, at higher magnification. Largely xenomorphic texture. Opaque grain is red hematite.

clasts. Nearly all exposures of the Atokan conglomerate 

throughout the region contain some pebbles of jasper 

(table R5). These pebbles suggest that jasperization had 

taken place and that jasper-bearing strata were subsequently eroded, with the siliceous sheets and nodules 

broken and slightly rounded into pebbles, prior to deposition of the upper slope unit of the Watahomigi Formation.

TABLE R5.—Recorded occurrences (number of localities) of jasper 

pebbles or clasts in conglomerates of the Supai Croup

_______________Conglomerates_______________ 

Esplanade Wescogame Manakacha Atokan Watahomigi

Number of

measured

..2 2 5 10 4

FIGURE R7.—Electron micrograph (x 15,000) of red-brown jasper from 

banded limestone bed at 73 ft above base of Manakacha Formation, 

Havasu Canyon, Ariz. Illustrates smooth, sharply defined faces of 

polyhedral blocks of quartz. Prepared by Kenneth Gardner.

The process of replacement of carbonate rocks by jasper 

may well have continued periodically through Atokan and 

later parts of Pennsylvanian time. Conglomerates in the 

Manakacha Formation and at the base of the Wescogame 

(fig. R5) indicate that local sources of jasper were being exposed at various times during the Pennsylvanian and were 

contributing material to these gravel beds. It seems unlikely that jasper in the Watahomigi was the only source 

for jasper in all later conglomerate beds. Rocks in the 

Watahomigi must have been buried too deeply to be exhumed by normal processes active in that region during 

later parts of the Pennsylvanian.

An environment suitable for the dissolving of carbonate 

rock and the precipitation of silica in its place quite certainly required the activity of slightly acid solutions. Such an 

environment is postulated for strata of the Supai Group 

during Early Pennsylvanian time when the region was at or 

near sea level and a cover of vegetation extended across 

much of the adjacent land. Major regressions mark the late 

stages of each formation in the Supai Group and terrestrial 

deposits were periodically accumulated above marine as 

indicated by the occurrence of land plants, land animals, 

and associated sedimentary structures at various intervals
374 THE SUPAI GROUP OF GRAND CANYON

in the stratigraphic column (see chapter I on regressions).

An alternative explanation accounting for the weakly 

acid environment considered necessary for the exchange of 

carbonates and silicates within limestones of the Supai was 

proposed by E. K. Maughan (written commun., 1978). He 

postulated that decomposition of algal and other organic 

matter within the carbonate beds would provide a likely 

process, involving an internal rather than external source 

of the acids. Maughan inferred that "the very shallow 

water deposition of the limestone beds and consequent, or 

even subsequent, exposure to an oxidizing environment 

may have been important factors in creating aerobic, 

rather than anaerobic, decomposition of the organic matter." Those limestones of the Supai that are lacking in 

jasper may therefore be explained, in part, as having remained in a reducing environment following deposition.

The high copper content in the jasper is consistent with 

the hypothesis stated above, according to Maughan, for 

"the 0.01 percent is only slightly less than 0.014 percent 

content of copper reported for phytoplankton." In a reducing environment "the copper would have been mobilized and probably expelled, but it has been retained as an 

oxide in the chert."

An hypothesis for the development of cryptocrystalline 

silica deposits of the type under discussion, based on textures observed under the electron microscope, has been 

suggested by Folk and Weaver (1952, p. 506). Because this 

hypothesis seems to explain satisfactorily the distinct but 

minute polyhedral blocks of quartz that form jasper of the 

Supai, it is here quoted in full:

[Prime control of the quartz development is] spacing of the centers of 

crystallization. It is suggested that microcrystalline quartz results when 

crystal growth begins at very numerous, closely spaced centers arranged 

in a three-dimensional array. The individual microcrystals, in random 

orientation, grow in all directions until they meet the advancing edges of 

adjacent microcrystals. If all crystallization centers are evenly spaced, the 

resulting microcrystals will form equant, polyhedral blocks of 

subuniform size such as those observed with the electron microscope. The 

surfaces of the blocks are slightly curved because they do not represent 

crystal faces, but merely the interface between two conformable 

masses . * * "The rate of formation presumably governs the closeness of 

the spacing, and this in turn determines the grain size of the chert.

AGE OF JASPER

Pebbles and angular clasts of reddish-brown jasper, 

mostly 0.25-0.5 in. in diameter, are included in various 

conglomerates of the Supai Group at many localities. A 

majority (10) of the recorded jasper pebble deposits are 

from the Atokan conglomerate of the Watahomigi Formation (table R5), but 5 are from conglomerates in the Manakacha and 2 from the basal conglomerate of the Wescogame. This distribution pattern is to be expected because 

strata of Morrowan age underlay the Atokan conglomerate and strata of Atokan age underlay channels in which 

the latter two conglomerates were deposited. These jasperbearing strata doubtless formed an abundant source of 

jasper pebbles in outcrops of the surrounding region.

Less easy to explain are the two occurrences of jasper 

pebbles in the basal conglomerate of the Esplanade (table 

R5). They are from channels exposed in National Canyon 

and Toroweap Valley and occur as rare angular to subrounded pebbles among an abundance of well-rounded 

sandstone, siltstone, and limestone pebbles of the normal 

assemblage in this conglomerate. Perhaps even more difficult to explain is the presence of jasper clasts in the basal 

conglomerate of the Watahomigi. At least two (Parashant 

and Bridge Canyons) of four occurrences are, at the base, 

resting upon a surface of Redwall Limestone, yet this type 

of jasper is not known to occur in the Redwall.

The presence of jasper in the form of pebbles or granules 

implies that jasperization must have occurred at a relatively early stage, certainly before the gravel was transported 

to its ultimate resting place within the conglomerate. Most 

of the jasper pebbles are angular to subangular, as might 

be expected considering both the durable nature of the 

material and the probability that the pebbles were locally 

derived from the abundant jasper beds or veins represented 

in older strata nearby. A few exceptions to the common 

angularity are clasts that probably were rolled about in a 

marine environment, for many of the conglomerates 

(Atokan, basal Watahomigi) of which these rounded 

jaspers are a part, also contain brachiopods.

REFERENCES CITED

Folk, R. L., and Weaver, C. E., 1952, A study of the texture and composition of chert: American Journal of Science, v. 250, no. 7, p. 498-510.

Goddard, E. N., chm., and others, 1948, Rock-color chart: National 

Research Council (reprinted by Geological Society of America, 1951, 

1963, 1970), 6 p.

Hughes, Paul, 1952, Stratigraphy of Supai formation, Chino Valley area, 

Yavapai County, Arizona: American Association of Petroleum 

Geologists Bulletin, v. 36, no. 4, p. 635-657.

Levering, T. G., 1972, Jasperoid in the United States—Its characteristics, 

origin, and economic significance: U.S. Geological Survey Professional Paper 710, 164 p.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

Noble, L. F., 1922, A section of the Paleozoic formations of the Grand 

Canyon at the Bass Trail: U.S. Geological Survey Professional Paper 

131, p. 23-73.

Spurr, J. E., 1898, Geology of the Aspen mining district, Colorado: 

U.S. Geological Survey Monograph 31, 260 p.

Walcott, C. D., 1880, The Permian and other Paleozoic groups of the 

Kanab Valley, Arizona: American Journal of Science, 3d ser., v. 20, 

p.221-225.
THE SUPAI GROUP OF GRAND CANYON

EVAPORITE DEPOSITS AND 

MAGNESIAN CARBONATE ROCKS

Chapter S 

By EDWIN D. McKEE

Contents

Evaporite deposits ........................................................................

Magnesian carbonate rocks ................................................................

General features .....................................................................

Ca-Mg ratios for carbonate rocks of the Supai Group ........................................

Ca-Mg ratios for carbonate rocks of the Watahomigi Formation ...............................

Ca-Mg ratios for carbonate rocks of the Manakacha Formation ................................

Ca-Mg ratios for carbonate rocks of the Wescogame Formation ...............................

Ca-Mg ratios for carbonate rocks of the Pakoon Limestone and Esplanade Sandstone ..............

References cited .........................................................................

375

Page

377

378

378

379

379

379

384

384

384
376 THE SUPAI GROUP OF GRAND CANYON

Illustrations Page

FIGURE SI. Map of northern Arizona and parts of adjacent states showing locations of principal

gypsum-anhydrite deposits of Early Permian age ................................ 378

S2-S5. Maps showing distribution of carbonate rocks, classified according to Ca-Mg ratio, in 

the:

52. Watahomigi Formation ............................................. 380

53. Manakacha Formation ............................................... 381

54. Wescogame Formation ................................................ 382

55. Pakoon Limestone .................................................... 383
EVAPORITE DEPOSITS AND MAGNESIAN CARBONATE ROCKS 377

EVAPORITE DEPOSITS

Of the four formations in the Supai Group, only the 

uppermost—the Esplanade Sandstone—contains evaporite 

deposits in the Grand Canyon region. These deposits consist of beds of gypsum and gypsiferous sandstone in the upper part of the formation. They are represented in sections 

northeast and east of the Grand Wash Cliffs (fig. Si, locality 1) where the Pakoon Limestone (McNair, 1951) intertongues with the Esplanade Sandstone. They were referred 

to by Fisher and Sorauf (1962, p. 651, fig. 1) as "a local 

gypsiferous facies present in the Hermit Formation below 

the Supai tongue and above the Esplanade."

The gypsiferous deposits in the Esplanade Sandstone 

range in thickness from 115 ft at Andrus Canyon to 74 ft at 

Toroweap Point, 20 mi to the east (fig. C8). They occur at 

Andrus and Parashant Canyons and in Toroweap Valley, 

but are absent in sections at Blue Mountain, Prospect Valley, and elsewhere to the south and southeast. Their extent 

in the subsurface to the north is unknown. These gypsiferous beds probably represent a belt or band of lagoons that 

formed among nearshore sands to the north and west of 

the Wolfcampian cross-stratified sands of the Grand Canyon area.

Evaporite deposits also occur in rocks of Early Permian 

(Wolfcampian) age west of the Grand Canyon region. 

They are recorded (Welsh, 1959, p. 80) from immediately 

above the Pakoon Limestone in southern Nevada at 

Frenchman Mountain, the Muddy Mountains, and at 

Pakoon Ridge. These evaporite deposits formed in an elongate northeast-trending basin (fig. Si, locality 2) suggesting (Welsh, 1959, fig. 9), "that the last environment of 

the Pakoon Formation was a widespread evaporating 

lagoon." Along the northwest margin of the lagoon were 

(barrier) bars built of sand detritus carried by longshore 

currents from the northeast and on the opposite margin 

was the "platform dolomite facies" of the Pakoon (Welsh, 

1959, p. 78).

The geographic relations in the Grand Canyon area between the sandstone facies and the gypsum facies of the 

Esplanade seem to be very different from those described 

for Nevada. In the Grand Canyon area, the gypsum accumulations are along the north margin of cross-statified 

sands and have an east-west linear trend. The evaporite 

deposits may represent a single long, narrow lagoon that 

extended from Andrus Canyon to Toroweap (about 20 mi) 

or they may represent several small lagoons as suggested 

by the absence of gypsum and the presence of flat-bedded 

sandstone in its place in the Whitmore Wash section. 

Although the gypsum deposits both in the Nevada and 

Grand Canyon areas are probably the same age and have 

about the same stratigraphic position with respect to 

dolostone of the Pakoon, no evidence is available to suggest that they were once connected.

Lower Permian (Wolfcampian) evaporite deposits near 

the San Juan River in southeastern Utah and northeastern 

Arizona (fig. SI, locality 3) are similar to the Esplanade 

gypsum deposits in most respects. These evaporites, like 

those of the Esplanade, consist mostly of gypsum or anhydrite in the subsurface, and generally occur as thin beds or 

disseminated through sandstone, within a sequence of 

shales, siltstones, and other red beds (Sears, 1956, p. 183). 

Furthermore, this gypsiferous sequence, called the Cedar 

Mesa Sandstone Member of the Cutler Formation, grades 

laterally into a massive, highly cross-stratified sandstone 

facies (O'Sullivan, 1965, p. 1), similar to that of the 

Esplanade.

The Cedar Mesa evaporite deposits differ from those of 

the Esplanade in the thickness of individual beds—some as 

much as 5 ft (O'Sullivan, 1965, p. 42)—and in their close 

association with limestone beds (Sears, 1956, p. 183; 

O'Sullivan, 1965, p. 41). These differences may be explained by differing degrees of marine restriction and the 

duration of evaporite conditions. Marine waters that were 

responsible for limestone and evaporites of the Cedar Mesa 

probably were derived directly from the sea to the east; 

those of the Esplanade were from the Cordilleran seaway 

to the west.

The Lower Permian evaporite deposits of the Cedar 

Mesa probably are far more extensive and numerous than 

indicated by the outcrops that have been described from 

southeastern Utah. Thin beds of anhydrite, which are 

reported from the subsurface of the eastern Wayne County 

in central Utah by the American Stratigraphic Co., 

Denver, Colo. (Hallgarth, 1967, p. 185) and other sources, 

suggest that scattered lagoons along margins of marine 

passages in the Grand Canyon region were periodically cut 

off and their waters subjected to concentration. As postulated by O'Sullivan (1965, p. 45) "the gypsiferous facies 

was deposited in a slight downwarp or basin" flooded 

"from time to time by an arm of the sea" where the gypsum 

"was deposited under conditions of high evaporation."

An extensive evaporite basin (fig. SI, locality 4) likewise 

developed southeast of the Grand Canyon region during 

Early Permian time (Huddle and Dobrovolny, 1945; 

McKee, and Oriel, and others, 1967, p. 212, fig. 80). This 

basin has been referred to as the Yeso evaporite basin 

(Elston, 1960, p. 33) and as the Permian Holbrook basin 

(Peirce, 1958; Peirce and Gerrard, 1966). The evaporitic 

sequence in this basin is called the "upper Supai" (Gerrard, 

1964). It ranges in thickness from 450 ft along its southern 

margin to 1,300 ft near the basin center and includes three 

principal lithofacies: (1) clastic facies, (2) halite-rich 

evaporite facies, and (3) sulfate-carbonate facies (Peirce 

and Gerrard, 1966, p. 9). The bedded halite is confined to a 

bfilt less than 50 mi wide and is nearly parallel to the basin 

axis that trends southeast-northwest.

Evaporites of the Holbrook basin consist of anhydrite,
378 THE SUPAI GROUP OF GRAND CANYON

112° 110°

Grand Canyon

Area of cross-bedded

sandstone

EXPLANATION 

Evaporite deposits

•;;.":^v.S: Mogollon Rim—margin of Colorado Plateau

FIGURE S1.—Northern Arizona and parts of adjacent states showing locations of principal gypsum-anhydrite deposits of Early Permian 

age: 1. Esplanade Sandstone, western Grand Canyon area (this paper). 2. Pakoon Limestone (McNair, 1951), southeastern Nevada 

region (modified from Welsh, 1959). 3. Evaporites of Cedar Mesa Sandstone Member (Cutler Formation), San Juan County, Utah 

(modified from O'Sullivan, 1965). 4. "Upper Supai" halite and gypsum, Holbrook basin (modified from Peirce, 1966).

gypsum, halite, and sylvite, interbedded with limestone, 

dolostone, and siliceous clastic deposits. The halite exhibits a considerable amount of lensing among the clastic 

deposits. The "sylvite occurs near the top of the halite sequence" and probably "originated as a precipitate from a 

final bittern phase of an evaporite environment" (Peirce 

and Gerrard, 1966, p. 9). The distribution pattern of 

evaporites suggests frequent shifting in time and space of 

the loci of accumulation. Probably marine waters to the 

south and southeast periodically entered a subsiding 

Holbrook basin and evaporite deposition resulted from 

intermittent restriction of the access ways, while an increasing influx of clastic sediment from the north gradually 

filled the basin (Peirce and Gerrard, 1966, p. 9). Trace and 

minor elements in anhydrite and halite of this basin are 

described and discussed by Dean and Tung (1974).

The southern Nevada, Holbrook, and southeastern Utah 

basins, which border the Grand Canyon embayment,

probably were contemporaneous or nearly contemporaneous with the Esplanade gypsum deposits and reflect a 

similar depositional environment. Therefore, a semiarid to 

arid climate with high evaporation is postulated for the 

entire region during Early Permian time when these evaporites accumulated. Areas in which the gypsum or anhydrite 

formed probably had a shallow-water, nearshore, lagoonal, or perhaps a sabkha-type environment.

MAG N ESI AN CARBONATE 

ROCKS

General features

Whether magnesian carbonate rocks of the Supai Group 

are of primary (including penecontemporaneous) origin or 

are late diagenetic is difficult to determine. Where the
EVAPORATIVE DEPOSITS AND MAGNESIAN CARBONATE ROCKS 379

dolostones are very fine grained with cryptocrystalline or 

microcrystalline texture as in the Pakoon Limestone and 

Wescogame Formation, they are believed to have developed on the sea floor either from direct precipitation or 

from early diagenesis and, therefore, probably reflect a 

semievaporitic environment of deposition. In contrast, the 

coarser-grained dolostones of the Watahomigi seem to indicate a secondary or late diagenetic origin resulting in 

recrystallization of the originally fine textured carbonate 

rock. Similar conclusions regarding genesis were reached 

by Lumsden, Ledbetter, and Smith (1973, p. 662) who 

believed that they could recognize the secondary dolostone 

by such features as fossil ghosts, micrite patches, and 

gradational boundaries between finely and coarsely crystalline textures.

Studies of insoluble residues by Lumsden (1974, p. 452) 

showed no significant correlation between the amount of 

residue and the dolomite content in rocks of mixed calcitedolomite mineralogy. A similar lack of relationship is found 

in analyses made of dolomitic rocks from the Grand Canyon region. Similarities both in residues and in dolomite 

content may result, however, from variations in nearshore 

processes, as suggested by Lumsden (1974, p. 445).

A common feature of carbonate rocks is their occurrence 

either as pure limestone or as pure dolostone, with 

relatively small amounts having intermediate composition. 

This characteristic has been recognized by numerous 

geologists (Steidtmann, 1917, p. 437; Scobey, 1940, p. 34; 

Chave, 1954, p. 599; Schmidt, 1965), and is clearly 

demonstrated in the Redwall Limestone that underlies the 

Supai Group in Grand Canyon (McKee and Gutschick, 

1969, p. 105). It has been described from southern Nevada 

in strata equivalent to the Supai (Lumsden, 1974, p. 451). 

The fact that most carbonate rocks are either entirely 

calcitic or entirely dolomitic seems to indicate that once 

begun, dolomitization tends to go to completion 

(Lumsden, 1974, p. 454). The rocks of intermediate 

composition commonly are referred to as rocks of mixed 

calcite-dolomite mineralogy. Such rocks seem to be 

moderately common in the Supai Group (figs. S2-S5), 

especially in the thick carbonate sequences of western 

Grand Canyon.

Where dolostones of the Supai are associated with claystones that occur either as lenses or as thin parting beds, 

the clay mineral represented almost invariably is illite, as 

described in chapter O. This association apparently reflects a specialized marine environment common to both.

Ca-Mg ratios for carbonate rocks 

of the Supai Group

The distribution and amount of carbonate rock and the 

proportions of dolomite to calcite in the carbonate rock are 

summarized for the Supai Group in figures S2-S5. The carbonates are classified according to the system of Guerrero 

and Kenner (1955, p. 46) into five groups, based on Ca-Mg 

molal ratio. These groups are as follows: limestone, more 

than 36.19; magnesian limestone, 17.67-36.19; dolomitic 

limestone, 2.85-17.67; calcitic dolostone, 1.2-2.85; and 

dolostone, less than 1.2. Proportions of each type for a 

particular locality are based on five or more samples per 

section. Where less than five samples were available for the 

calculation, blank slices in the pie diagram indicate the 

number of carbonate rocks without analysis.

For this study 524 samples of carbonate rock, representing the four formations of the Supai Group and the 

Pakoon Limestone throughout the Grand Canyon region, 

were selected for analysis. The molal ratio of calcium oxide 

to magnesium oxide—a measure of excess calcium over 

that needed for pure dolostone—has been calculated from 

the CaO-MgO determinations. All magnesium in the calculations is assumed to be in the form of dolomite, and 

calcium in excess of that required for a 1:1 molal ratio with 

magnesium is considered to be in the form of calcite.

Ca-Mg ratios for carbonate rocks 

of the Watahomigi Formation

In the western part of the Grand Canyon region most of 

the Watahomigi Formation is composed of carbonate 

rocks and where these carbonate rocks are more than 100 

ft thick, limestone is the dominant type. In most places, 

limestone constitutes 75 percent or more of the total. Only 

at Iceberg Canyon (fig. S2) is the percentage of limestone 

less than 50 percent. The especially high amount of dolostone and calcitic dolostone at that locality possibly is accounted for by secondary dolomitization related to faulting.

Ca-Mg ratios for carbonate rocks 

of the Manakacha Formation

Carbonate rocks of the Manakacha Formation show two 

definite trends from east to west across the Grand Canyon 

region (fig. S3). First, they increase from less than 50 ft in 

thickness in the east to more than 100 ft in the extreme 

west. Second, carbonate rocks high in magnesium, as 

shown by molal ratios, are entirely in western Grand Canyon. The significance of this distribution pattern (fig. S3) is 

not clearcut, but because some of the Manakacha Formation in the western area is essentially free of dolostone and 

no definite trend in high magnesium carbonate distribution 

is apparent, a control by depositional environment seems 

unlikely. The magnesian rocks may be secondary and 

structurally controlled.
380

114°

36'

THE SUPAI GROUP OF GRAND CANYON

113° 112°

EXPLANATION

Circle size represents carbonate rock thickness, in feet 

Each pie based on 5 or more samples

>100

50-100

<50

Ca-Mg molal ratios 

More than 36.19 Limestone

17.67-36.19 Magnesian limestone 

2.85-17.67 Dolomitic limestone

1.2-2.85 Calcitic dolostone 

Less than 1.2 Dolostone

FIGURE S2.—Distribution of carbonate rocks, classified according to Ca-Mg ratio, in the Watahomigi Formation of Grand Canyon, Ariz.

Numbers above pies are those of measured sections (fig. A1).

Rock type 

Limestone

Magnesian limestone 

Dolomitic limestone 

Calcitic dolostone 

Dolostone 

Carbonate rocks without analysis
EVAPORITE DEPOSITS AND MAGNESIAN CARBONATE ROCKS

113° 112°

381

36°-

EXPLANAHON

Circle size represents carbonate rock thickness, in feet 

Each pie based on 5 or more samples

>100

50-100

<50

Ca-Mg molal ratios 

More than 36.19 Limestone

17.67-36.19 Magnesian limestone 

2.85-17.67 Dolomitic limestone

1.2-2.85 Calcitic dolostone 

Less than 1.2 Dolostone

FIGURE S3.—Distribution of carbonate rocks, classified according to Ca-Mg ratio, in the Manakacha Formation of Grand Canyon, Ariz.

Numbers above pies are those of measured sections (fig. A1).

Rock type 

Limestone

Magnesian limestone 

Dolomitic limestone 

Calcitic dolostone 

Dolostone 

Carbonate rocks without analysis
382

36°-

THE SUPAI GROUP OF GRAND CANYON 

113° 112°

EXPLANATION

Circle size represents carbonate rock thickness, in feet 

Each pie based on 5 or more samples

>100

50-100

<50

Ca-Mg molal ratios 

More than 36.19 Limestone

17.67-36.19 Magnesian limestone 

2.85-17.67 Dolomitic limestone

1.2-2.85 Calcitic dolostone 

Less than 1.2 Dolostone

FIGURE S4.—Distribution of carbonate rocks, classified according to Ca-Mg ratio, in the Wescogame Formation of Grand Canyon, Ariz.

Numbers above pies are those of measured sections (fig. A1).

Rock type 

Limestone

Magnesian limestone 

Dolomitic limestone 

Calcitic dolostone 

Dolostone 

Carbonate rocks without analysis
114°

EVAPORITE DEPOSITS AND MAGNESIAN CARBONATE ROCKS

113° 112°

383

37°

36C

EXPLANATION

Circle size represents carbonate rock thickness, in feet 

Each pie based on 5 or more samples

>100

50-100

<50

Ca-Mg molal ratios 

More than 36.19 Limestone

17.67-36.19 Magnesian limestone 

2.85-17.67 Dolomitic limestone

1.2-2.85 Calcitic dolostone 

Less than 1.2 Dolostone

Rock type 

Limestone

Magnesian limestone 

Dolomitic limestone 

Calcitic dolostone 

Dolostone 

Carbonate rocks without analysis

FIGURE S5—Distribution of carbonate rocks, classified according to Ca-Mg ratio, in the Pakoon Limestone (McNair, 1951) and Esplanade Sandstone of Grand Canyon, Ariz. Numbers above pies are those of measured sections (fig. A1).
384 THE SUPAI GROUP OF GRAND CANYON

Ca-Mg ratios for carbonate rocks 

of the Wescogame Formation

The proportion of carbonate rock to detrital rock in the 

Wescogame Formation is lower than in either of the underlying Pennsylvanian formations. Throughout eastern and 

central Grand Canyon, the total thickness of Wescogame 

carbonates is less than 100 ft and in several sections of central Grand Canyon, carbonate rocks are lacking. Coincidentally, the Wescogame Formation in the central area 

where no dolostone occurs, has exceptionally high sand accumulation (70-100 percent).

Ca-Mg molal ratios (fig. S4) indicate that only a small 

percentage of the Wescogame carbonate rocks contain 

appreciable amounts of magnesium. Rocks ranging from 

magnesian limestone to "pure" dolostone occur both in the 

far eastern and far western parts of the region, but are not 

recorded from the middle part.

Ca-Mg ratios for carbonate rocks 

of the Pakoon Limestone 

and Esplanade Sandstone

The great mass of detrital sediment, mostly very fine 

grained sand, that comprises the Esplanade Sandstone 

doubtless precluded deposition of any appreciable amount 

of carbonate sediment in the Grand Canyon area. A few 

thin beds of limestone in some sections in the middle and 

western parts of the area are interpreted as tongues that 

extend eastward from the Pakoon Limestone in extreme 

northwestern Arizona.

The Pakoon, now established as a lateral equivalent of 

the lower part of the Esplanade Sandstone, represents a 

nearly complete change of lithofacies within a relatively 

few miles. It occurs between sections along the Grand 

Wash Cliffs (fig. Al, sees. 28, 29, 30) and the nearest outcrops to the east (sees. 24 and 25). The lateral termination 

of about 250 ft of carbonate rock, and the beginning of a 

sandstone sequence, with little recognizable intertonguing 

between, is a striking feature that requires explanation.

Carbonate rock of the Pakoon has low Ca-Mg ratios. 

Sections at Hidden Canyon and Pigeon Wash on the 

Grand Wash Cliffs and at Iceberg Canyon (fig. S5) show 

dolostone and calcitic dolostone to be about 50 percent or 

more of the carbonate rock, and, in numerous sections farther west, a similar high magnesium content has been 

recognized (Welsh, 1959; Lumsden, 1974). This distribution pattern, with much dolostone along the eastern 

margin of the Pakoon Limestone adjacent to the sand mass 

of the Esplanade, probably suggests a depositional environmental control, rather than a secondary structurally 

controlled diagenesis.

REFERENCES CITED

Chave, K. E., 1954, Aspects of the biogeochemistry of magnesium—[pt.] 

1, Calcareous marine organisms; [pt.] 2, Calcareous sediments and 

rocks: Journal of Geology, v. 62, no. 3, p. 266-282; no. 6, p. 587-599.

Dean, W. E., and Tung, A. L., 1974, Trace and minor elements in anhydrite and halite, Supai Formation (Permian), east-central Arizona, in 

A. H. Coogan, ed., Fourth symposium on salt, v. 1, Geochemistry 

and mineralogy: Cleveland, Ohio, Northern Ohio Geological Society, p. 287-301.

Elston, W. E., 1960, Structural development and Paleozoic stratigraphy 

of Black Mesa basin, northeastern Arizona, and surrounding areas: 

American Association of Petroleum Geologists Bulletin, v. 44, 

p. 21-36.

Fisher, W. L., and Sorauf, J. E., 1962, Correlation chart of the Permian 

formations of North America—Discussion of the Grand Canyon section: Geological Society of America Bulletin, v. 73, p. 649-752.

Gerrard, T. A., 1964, Stratigraphy of the Fort Apache Member, Supai 

Formation (Permian), east-central Arizona, in Contributions to the 

geology of northern Arizona—Major Brady Memorial: Museum of 

Northern Arizona Bulletin 40, p. 33-48.

Guerrero, R. G., and Kenner, C. T., 1955, Classification of Permian 

rocks of western Texas by a versenate method of chemical analysis: 

Journal of Sedimentary Petrology, v. 25, no. 1, p. 45-50.

Hallgarth, W. E., 1967, Western Colorado, southern Utah, and northwestern New Mexico, in McKee, E. D., and Oriel, S. S., and others, 

Paleotectonic investigations of the Permian System in the United 

States, chapter I: U.S. Geological Survey Professional Paper 515, 

p. 171-197.

Huddle, J. W., and Dobrovolny, E., 1945, Late Paleozoic stratigraphy 

and oil and gas possibilities of central and northeastern Arizona: 

U.S. Geological Survey Oil and Gas Investigations Preliminary 

Chart 10.

Lumsden, D. N., 1974, Relationships among insoluble residue, dolostone 

and limestone fades: Journal of Sedimentary Petrology, v. 44, no. 2, 

p. 450-455.

Lumsden, D. N., Ledbetter, M. T., and Smith, G. T., 1973, Lithostratigraphic analysis of the Bird Spring-Callville Group and Pakoon Formation (Pennsylvanian-lower Permian), southern Clark County, 

Nevada: Journal of Sedimentary Petrology, v. 43, no. 3, p. 655-671.

McKee, E. D., and Gutschick, R. C., 1969, History of the Redwall Limestone of northern Arizona: Geological Society of America Memoir 

114, 726 p.

McKee, E. D., and Oriel, S. S., and others, 1967, Paleotectonic investigations of the Permian System in the United States: U.S. Geological 

Survey Professional Paper 515, 271 p.

McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern 

Arizona: American Association of Petroleum Geologists Bulletin, 

v. 35, no. 3, p. 503-541.

O'Sullivan, R. B., 1965, Geology of the Cedar Mesa-Boundary Butte 

area, San Juan County, Utah: U.S. Geological Survey Bulletin 1186, 

128 p.

Peirce, H. W., 1958, Permian sedimentary rocks of the Black Mesa basin 

area, in New Mexico Geological Society Guidebook, 9th Field Conference, October 1958: p. 82-87.

Peirce, H. W., and Gerrard, T. A., 1966, Evaporite deposits of the Permian Holbrook basin, Arizona, in Second symposium on salt, v. 1, 

Geology, geochemistry, mining: Cleveland, Ohio, Northern Ohio 

Geological Society, p. 1-10.

Sears, J. D., 1956, Geology of Comb Ridge and vicinity north of San 

Juan River, San Juan County, Utah: U.S. Geological Survey Bulletin 

1021-E, p. 167-207.
EVAPORITE DEPOSITS AND MAGNESIAN CARBONATE ROCKS 385

Schmidt, V., 1965, Facies, diagenesis, and related reservoir properties in Steidtmann, Edward, 1917, Origin of dolomite as disclosed by stains

the Gigas beds (Upper Jurassic), northeastern Germany: Society of and other methods: Geological Society of America Bulletin, v. 28,

Economic Paleontologists and Mineralogists Special Publication 13, p. 431-450.

p. 124-168. 

Scobey, E. H., 1940, Sedimentary studies of the Wapsipinicon forma- Welsh, H. E., 1959, Biostratigraphy of the Pennsylvanian and Permian

tion in Iowa: Journal of Sedimentary Petrology, v. 10, no. 1, p. 34-44. Systems of southern Nevada: Utah University, Ph. D. thesis, 106 p.

Measured stratigraphic sections of the Supai Group, Grand Canyon,

Arizona1

*In Western Grand Canyon includes Pakoon Limestone of McNair, A. H., 1951, Paleozoic stratigraphy 

of part of northwestern Arizona: American Association of Petroleum Geologists Bulletin, v. 35, no. 3, 

p. 503-541.
388 THE SUPAI GROUP OF GRAND CANYON

114'

FIGURE MS1.—Locality map of Grand Canyon region, Arizona, showing positions (solid circles) of numbered measured stratigraphic sections (1-35).

Arrow and miles indicate direction and distance to actual locality of section.

NOTES ON TERMINOLOGY

Names of carbonate rocks, where based on analyses of quantitative 

data (molal ratio), follow the five-fold system of Cayeux1 and of Pettijohn2 . The modifying adjective as calcitic, dolomitic, or magnesian, 

follows the principal name in its description and is separated by a 

comma.

Most of the color names are based on the Rock Color Chart3 ; determination was by visual comparison, and terminology conforms with 

that of the chart. Hyphenation follows U.S. Government Printing Office style for unit modifiers.

Names of grain sizes follow those of the Went worth Scale (see also 

chapter A, p. 10) and use the terminology throughout of very coarse, 

coarse, medium, fine, and very fine as determined by analysis or by 

grain comparison on slides.

lCayeux, Lucien, 1935, Les roches sedimentaires de France; Roches carbonattes (calcaires et dolomies): Paris, Masson, 

463 p.

2 Pettijohn, F. ]., 1949, Sedimentary rocks: New York; Harper and Bros., p. 312.

3Goddard, E. N., and others, 1948, Rock color chart: National Research Council (reprinted by Geological Society of 

America, 1951, 1970), 6 p.
THE SUPAI GROUP OF GRAND CANYON

MEASURED STRATIGRAPHIC

SECTIONS

By EDWIN D. McKEE

Contents

	Page

SECTION 1a. House Rock Canyon _____________________________________ 391

1 b. Near mile 22, Marble Canyon —————-——-——————————-———.—.————— 391

2. Twentynine Mile Canyon —————————————————————————————-————— 391

*3 Fm i nence Fau It ____________________________________________ 39 S

4 Blue Spring ___________________________________________ 397

A j Horsetrai I Canvon __________________________________________ 399

5. Bunker Trail ___________________________________________ 401

A r~jrptnHv'ifiyv TraiI ___________________________________________ 404

7 KaibabTrail south _______________________________________ 407

8 Kaibab Trail north _______________________________________ 411

9. Hermit Trail ___________________________________________ 414

10. Bass Trail ____________________________________________ 418

11 Shinumo Trail __________________________________________ 422

12 Thunder River Trail _______________________________________ 423

i ^ ToDOCoba Trail ____________________________________________ 426

i A Havasu Canvon ________________________________________ ___ 427

i ^ National Canvon ___________________________________________ 431

i A lOinab Canvon ______________________________________________ 43f>

17 SB Canyon ___________________________________________ 438

18. Tuckup Canyon ——————————————————————————-—————————————— 442

iQ Blue Mountain Canvon _______________________________________ 445

20 Prospect Valley _________________________________________ 447

2 la. Toroweap Valley (east side)-----------------------"--"------------------———TM——-———TM———— 449

21 b. Toroweap Valley (west side) ———————————————-———-————————-————— 452

22a Whitmore Wash (part) _____________________________________ 453

22b. Whitmore Wash (part) _____________________________________ 457

23 Parashant Canvon __________________________________________ 458

24 Andrus Canvon ____________________________________________ 461

25 Twi n Son nss Canvon ________________________________________ 464

26 CHuano Cave _____________________________________________ 468

27 Snao Canvon _____________________________________________ 471

28. Pigeon Wash _____________________________________________ 475

29 Grand Gulch Mine (Dart) ____________________________________ 479

30a Hidden Canyon (part) _____________________________________ 481

30b H idden Canyon (part) _____________________________________ 483

30c H idden Canvon (oart) _____________________________________ 486

31 Icebers Canvon _________________________________________ 487

32 Selisman ____________________________________________ 492

34 Seoaration Canvon _________________________________________ 492

35 H indu Canvon ____________________________________________ 496

Illustrations

	Page

FIGURE MS1. Map showing localities of measured sections —————————-—————————————— 388

MS2. Color photographs of strata of Supai Group ———————————————————————-—- 390
390 THE SUPAI GROUP OF GRAND CANYON

FIGURE MS2.—Strata of Supai Group, Grand Canyon, Ariz. A, Tabularplanar sets of cross-strata in middle of Esplanade Sandstone, main cliffunit. Sandstone foresets show variation of orange-pink to reddish-orange 

color characteristic of most surfaces in this unit. Apache Trail into 

Havasu Canyon. 8, Massive sandstone beds of cliff unit of Wescogame 

Formation (We) are mostly various shades of grayish orange-pink. Channels near base are filled with conglomerate. Manakacha Formation (M) 

below. Thunder River Trail. C, Cliff of Manakacha Formation (M) in right 

foreground. Massive beds of limestone and sandstone of Manakacha cliff 

unit show normal reddish brown in lower part and black varnished surfaces in upper part; thin slope unit at top is moderate reddish orange. 

Wa, Watahomigi Formation; We, Wescogame Formation; E, Esplanade 

Sandstone. Strata form walls of Havasu Canyon above Supai Village. D, 

Window of Watahomigi Formation (Wa) with basalt flows on each side; 

base of Manakacha Formation (M) cliff above and Redwall Limestone (R) 

cliff below. Total thickness of Watahomigi is 215 ft. Deep reddish brown 

of mudstone slopes largely concealed by talus; limestone and sandstone 

ledges appear as dark brown on weathered surfaces. Marine fossils 

numerous on lower siltstone slopes and conglomerate ledges. West side 

of Toroweap Valley, south of Colorado River.
MEASURED STRATIGRAPHIC SECTIONS 391

Section 1a (part) 

HOUSE ROCK CANYON

[Basal conglomerate of Esplanade Sandstone at mile 16.5 in Marble 

Canyon, west wall]

Esplanade Sandstone:

Main cliff and basal slope units not measured here. 

Conglomerate, forms lenses within channels at base of 

basal slope unit; channels 40-50 ft deep and extend 

laterally about 260 ft. 

Matrix: calcareous sandstone. 

Gravel: gray, aphanitic, laminated limestone; redbrown siltstone; purple, aphanitic limestone; 

dark-gray limestone; pale-red sandstone. 

Sphericity—spherical to flat; limestones mostly

platy, siltstones and sandstones spherical. 

Roundness—well-rounded to angular; limestones 

largely angular or subangular; siltstones 

rounded.

Size—average 0.5-1 in. Maximum—sandstone 

block 18 by 6 in.; sandstones 11 and 7 in. diameters; limestone 6 in. diameter.

Section 1b (part) 

NEAR MILE 22, MARBLE CANYON

[Upper part of Watahomigi Formation measured in west side of Colorado River near Mile 23]

Feet

Supai Group:

(Overlying cliff-forming beds not examined) 

Manakacha Formation or upper slope unit of 

Watahomigi:

Limestone, gray-brown, and conglomerate, 

gray-brown to black, beds medium (1-2 ft), 

some beds contorted on large scale; Pennsylvanian age solution channel filled with purple 

mudstone; forms basal unit of cliff; 

weathers to rough surface —————————— 1.0 

Matrix: limestone, light- to dark-gray. 

Gravel: abundant jasper and black chert, 

some dark-gray, silty limestone; chert pebbles angular, carbonate pebbles rounded 

to subrounded; diameters mostly 0.25-0.5 

in., maximum 2 in. 

Contact:

Irregular wavy surface. 

Watahomigi Formation:

Sandstone, red-brown, very fine grained, 

friable; cross-stratified on medium scale; 

weathers to weak cliff with receding ledges 

at top ————————————-————————— 25.0 

Concealed: talus-covered slope ————————— 58.0

Section Ib — Continued 

NEAR MILE 22, MARBLE CANYON-Continued

Feet

Supai Group — Continued 

Watahomigi Formation — Continued

(Basal conglomerate measured on east side of

river)

Conglomerate, red-brown to light-gray, limy; 

forms rounded massive cliff; rests on karst 

surface of Redwall Limestone ————————— 4.0 

Matrix: dark-red-brown silty limestone. 

Gravel: light-gray limestone, dark-gray 

limestone, purple silty limestone; mostly 

rounded to subrounded; diameters largely 

0.5-1 in., maximum 4 in. ____

Total Watahomigi Formation — 87.0

Section 2 

TWENTYNINE MILE CANYON

[Along northeast wall at Marble Canyon (section progresses up Twentynine Mile Canyon)]

Hermit Shale:

Siltstone, pale-reddish-brown, shaly; forms 

slope —————————————————————

Contact:

No erosion surface apparent near line of section. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope unit:

Sandstone, moderate-orange-pink, very fine 

grained; contains tabular-planar crossstratification on large scale (20-30 ft); forms 

resistant ledge ————————-

Mudstone, moderate-reddish-brown, crumbly; 

forms slope and recess ——————————

Siltstone, red-brown, medium-bedded; forms 

ledges ————————————-

Sandstone, moderate-reddish-orange, very fine 

grained, very calcareous, friable, flatbedded, thin-bedded (2-12 in.); contains 

much silt, skeletal fragments; forms series of 

receding ledges —————————————

Sandstone, very pale orange, very fine grained, 

hard; contains tabular-planar cross-stratification on large scale (20-30 ft); weathers 

red-brown; forms resistant ledge ——————

Mudstone, dark-reddish-brown, structureless; 

forms slope ———————————————

Limestone, grayish-red-purple, very fine 

grained, thin-bedded (1-2 in.); very irregular 

surface; forms slope ——————————

Feet

5.5

— 10.0

9.0

_______________ 8.0

7.0

16.0

16.0

3.0
392 THE SUPAI GROUP OF GRAND CANYON

Section 2—Continued 

TWENTYNINE MILE CANYON—Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope unit—

Continued

Mudstone, pale-reddish-brown, flat-bedded,

thin-bedded (1-5 in.); forms slope —————— 4.0

Siltstone, very pale orange, structureless, very 

hard, calcareous; forms resistant ledge ——— 1.5

Mudstone, moderate-reddish-orange, crumbly;

forms slope and recess ————————————— 8.5

Sandstone, moderate-orange-pink, very fine 

grained, thick-bedded (3-6 ft); contains 

wedge-planar cross-stratification on large 

scale (10-20 ft); forms resistant ledges ———— 14.5

Mudstone, moderate-reddish-brown, crumbly,

structureless; forms slope or recess ————— 1.5

Sandstone, pale-orange, very fine grained (68 

percent), fine-grained (26 percent), limy (30 

percent), thick-bedded (6-10 ft), weakly 

cross-stratified; weathers to rounded surface; forms series of receding ledges ————— 24.0 

Total upper cliff-slope unit, Esplanade Sandstone —————— 123.0 

Esplanade Sandstone, main cliff unit:

Sandstone, grayish-white, fine-grained to very 

fine grained, hard; contains tabular- and 

wedge-planar cross-stratification; locally 

weathers white; forms cap of main cliff ——— 10.0

Limestone, olive-gray, very fine grained, 

structureless, hard, silty; brown silt grains 

weather out on surface; forms resistant 

ledge —————————————————————— 3.0

Sandstone, pale-orange, very fine grained (59 

percent), fine-grained (31 percent), resistant, 

calcareous (21 percent); contains tabularplanar cross-stratification on large scale 

(30-40 ft); weathers brown, locally white; 

forms resistant cliff —————————————— 11.0

Mudstone, deep-red-brown, crumbly; forms 

recess —————————————————————— 2.0

Sandstone, moderate-orange-pink, very fine 

grained; contains planar cross-stratification 

on large scale (30-40 ft) throughout; thick 

unit; weathers to pale-brown surface; forms 

prominent straight cliff ———————————— 33.0

Sandstone, moderate-orange-pink, very fine 

grained, hard, thick-bedded (2-4 ft); 

weathers to rounded spheroidal surface;

1 rr\i*TYic \Ji II13 r*lirr Clil 1 ———————————— —————————————————————— — 1 j^ *7 ^ O^j

Mudstone, moderate-reddish-brown, structureless; forms recess ———————————————— 2.0

Section 2—Continued 

TWENTYNINE MILE CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, main cliff-slope unit—

Continued

Sandstone, very pale orange to moderatereddish-orange, very fine grained, calcareous, structureless, thick-bedded (2-8 ft); 

beds separated locally by thin partings of 

deep-red-brown mudstone; weathers redbrown; forms cliff ———————————————

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, hard, structureless to 

weakly cross-stratified (tabular-planar 

type); includes two layers, each 10-20 ft 

thick, with thin parting of deep-red-brown 

mudstone between; weathers to black surface; grades laterally into gray silty limestone; forms part of main cliff ————————

Sandstone, pale-gray to reddish-brown, very 

fine grained (64 percent), fine-grained (30 

percent), very limy (50 percent), hard; clean 

quartz grains; contains tabular-planar crossstratification on large scale (20-25 ft); 

weathers to black surface; forms cliff ————

Feet

28.5

31.5

51.5

Total main cliff unit, Esplanade

Sandstone ——————————— 184.5

Esplanade Sandstone, basal slope unit:

Mudstone, moderate-reddish-brown, limy, 

crumbly; contains layers of intraformational 

mud pellets and local white spots (deoxidized patches) ; forms recess ——————————

Siltstone, pale-reddish-brown, calcareous, 

hard, thick-bedded (4-6 ft); contains thin 

partings of deep-red mudstone; weathers to 

black surface; forms cliff ———————————

Sandstone, moderate-reddish-orange, very fine 

grained, thin-bedded (6-24 in.); alternates 

with moderate-reddish-brown, shaly siltstone; total includes one thin (6 in.) bed of 

olive-gray rubbly limestone 16 ft above 

base; forms slope with receding ledges ————

Sandstone, moderate-reddish-brown, very fine 

grained (15 percent), silty (31 percent), friable, thin-bedded (2-12 in.); forms weak

5 . 0

16.5

Conglomerate, irregular channel-scoured base 

where observed; forms ledge ————————— 

Matrix: gray- to moderate-reddish-brown, 

very fine grained sandstone.

31.5

12.0

5.0
MEASURED STRATIGRAPHIC SECTIONS 393

Section 2—Continued 

TWENTYNINE MILE CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, basal slope unit 

Conglomerate—Continued

Gravel: pale-red, medium-gray, and olivegray limestone and moderate-reddishbrown siltstone; well-rounded; many pebbles elongate and oriented parallel to bedding; diameter maximum 4 in., 2 in. common, mostly 0.25-1 in.

feet

Total basal slope unit, Esplanade Sandstone ——————— 70.0 

Total Esplanade Sandstone ——— 377.5

Wescogame Formation, slope and cliff units:

Siltstone, moderate-reddish-brown, thickbedded (1-3 ft); contains thin parting zones 

of moderate-reddish-brown, structureless 

mudstone; locally forms weak cliff ————— 17.5

Limestone, dark-olive-gray to purple, concretionary; includes some moderate-reddishbrown mudstone; limy masses locally 

weather to greenish surface with gray rodlike structures; total forms slope with very 

weak rounded ledges ————————————— 20.0

Sandstone, moderate-orange-pink, very fine 

grained, structureless, very hard; forms 

resistant ledge ————————————————— 7.5

Siltstone, pale-reddish-brown, concretionary; 

forms weak ledge and slope —————————— 14.0

Sandstone, moderate-reddish-orange, very fine 

grained, structureless; contains scattered 

limy concretions ———————————————— 9.5

Mudstone, deep-red, brittle; forms slope ——— 4.0

Sandstone, pale-orange-pink, very fine grained, 

calcareous; contains planar cross-stratification on large scale; weathers to black surface; forms cliff————————————————— 12.0

Siltstone, dark-reddish-brown; contains concretionary structures (balls of limy mudstone, 2-3 in. in diameter) throughout; 

moderately resistant; forms recess and base

r»f \Ji rliff Hill _____________________________ ——~~—— — — —— —.—_.— — ____L*±. 14. n\J

Total Wescogame Formation —— 98.5

Section 2 — Continued 

TWENTYNINE MILE CANYON-Continued

Supai Group — Continued 

Manakacha Formation, slope unit — Continued 

Sandstone, moderate-reddish-orange, very fine

grained; cross-stratified on medium scale;

forms cliff ———————————————————— 

Siltstone, pale-reddish-brown, mediumbedded; forms cliff ——————————————— 

Siltstone, dark-reddish-brown, shaly, crumbly;

contains gray nodular balls of limestone,

0.25-0.5 in. in diameter; forms slope ————— 

Limestone, dark-reddish-brown, very fine

grained, structureless, silty; weathers

brown; forms resistant ledge ————————— 

Mudstone, deep-reddish-brown, crumbly;

forms slope ——————————————————— 

Sandstone, moderate-orange-pink, very fine

grained; cross-stratified on medium scale

(5-10 ft); friable; forms cliff — — — - — — — - 

Siltstone, pale-red, calcareous, mediumbedded (1-2 ft); weathers red; forms cliff —— 

Mudstone, moderate-reddish-brown, crumbly,

Siltstone, moderate-reddish-orange, friable; 

contains limy balls, 0.5-1 in. in diameter, in 

upper part; grades into pure gray limestone 

at top; forms slope ———————————————

Mudstone, deep-reddish-brown, crumbly; 

forms slope ———————————————————

Sandstone, moderate-reddish-orange, very fine 

grained, structureless; forms ledge ——————

Siltstone, moderate-reddish-brown, shaly, 

locally nodular; forms slope —————————

Siltstone, moderate-reddish-brown, shaly, 

nodular; contains scattered hard balls of 

gray limy siltstone covered with thin layers 

of shaly red-brown siltstone; forms weak

13.0 

7.5

6.5

2.5 

2.0

7.0 

18.0

6.0 

4.0 

1.5 

4.0

Manakacha Formation, slope unit:

Sandstone, pale-reddish-brown, muddy, 

crumbly, irregularly bedded; locally forms 

weak ledge, commonly forms slope ————— 12.5

Total slope unit, Manakacha

Formation ——————————— 98.0

Manakacha Formation, cliff unit:

Sandstone, pale-orange-pink, poorly sorted; 

lower part flat-bedded, upper part wedgeplanar, cross-stratified; weathers to light-red 

surface; forms cliff with vertical even face — 11.0

Limestone, pale-red, nodular; contains patches 

of red-brown siltstone; weathers to rounded 

nodular surface; forms recess ————————— 3.0

Siltstone, moderate-reddish-brown, structureless, moderately resistant; forms ledge ———— 5.0
394 THE SUPAI GROUP OF GRAND CANYON

Section 2 — Continued 

TWENTYNINE MILE CANYON-Continued

Supai Group — Continued 

Mankacha Formation, cliff unit — Continued 

Mudstone, deep-reddish-brown, crumbly; 

forms recess ———————————————————

Sandstone, moderate-orange-pink, fine- (52 

percent) to very fine grained (39 percent), 

calcareous (30 percent); contains wedgeplanar cross-stratification on small to

medium scale (1-10 ft); forms prominent 

cliff ..___.— — _......__„..__...._...__..______._____

Limestone, medium-light-gray, very fine

grained, medium-bedded (2-3 ft); weathers

to irregular knobby surface; forms cliff ———

Siltstone, pale-red, crumbly, structureless;

forms slope, largely concealed ————————

Limestone, light-brownish-gray, very fine

grained, hard, structureless; silty laminae

locally etched out; forms cliff —————————

Siltstone, bright-red, structureless; resistant ——

Limestone, light-brownish-gray, very fine

grained to aphanitic, concretionary; contains patches of purple siltstone; forms

rounded ledge —————————————————

Siltstone, pale-reddish-brown, flat-bedded,

thin-bedded (1-12 in.); resistant ———————

Siltstone, shaly, nodular —————————————

Siltstone, bright-red, structureless ———————

Limestone, gray; contains jasper ————————

Siltstone, shaly, nodular —————————————

Siltstone, bright-red, structureless ———————

Limestone, gray, aphanitic; contains bands of

Feet

1.0

10.0

7.0 

7.0

9.5

5.5

4.5

3.0 

1.5 

2.0 

2.0 

2.0 

1.0

——•—< ————— - —— .————————————————— TM———TM—TM.TM—TM *J • v

Sandstone, pale-red, very fine grained, limy, 

shaly, thin-bedded (0.5-1 in.); contains limy 

concretions ——————————————————— 6.5 

Limestone, gray, aphanitic; contains bands of 

jasper; contains rounded limestone pebbles 

near top ————————————————————— 5.0 

Sandstone, moderate-reddish-brown, very fine 

grained, flat-bedded; forms massive ledge — 5.5 

Total cliff unit, Manakacha

Formation ——————————— 95.0 

Total Manakacha Formation —— 193.0

Watahomigi Formation:

Limestone, gray, aphanitic; contains bands of

Section 2—Continued 

TWENTYNINE MILE CANYON—Continued

feet

Supai Group—Continued

Watahomigi Formation—Continued

Sandstone, moderate-reddish-orange, very 

fine grained, flat-bedded ——————————— 3.0

Limestone, grayish-red, very fine grained,

hard; contains bands of jasper ———————— 4.0

Mudstone, deep-red, crumbly; forms recess—— 1.0

Siltstone, pale-reddish-brown, shaly, thinbedded; concretionary near top with gray 

rounded spheres, 0.5-1 in. in diameter; 

forms weak cliff ———————————————— 11.0

Limestone, gray; contains bands of jasper;

forms resistant cliff ——————————————— 5.5

Mudstone, dark-grayish-red, brittle; includes

dolomite (15 percent); forms recess —————— 4.5

Limestone, light-olive-gray, aphanitic; contains bands of jasper; forms ledge ——————— 2.0

Mudstone, deep-red-brown; forms recess ——— 2.0

Siltstone, moderate-reddish-brown, sandy, 

crumbly; mostly flat-bedded and shaly, but 

locally cross-stratified at low angles; contains small (0.5 in.) white siltstone concretions scattered throughout; forms weak cliff - 9.5

Mudstone, deep-reddish-brown; forms recess — 2.0

Limestone, light-brownish-gray, very fine 

grained to aphanitic; nodular with purple 

siltstone patches; contains local bands of 

jasper; forms base of cliff ——————————— 3.0

Mudstone and siltstone, interlayered. Mudstone is moderate-reddish-brown, crumbly; 

forms series of slopes, 1-3 ft thick. Siltstone 

is pale red, forms ledges, 0.5-2 ft thick ———— 11.0

Dolomite, calcitic, light-olive-gray, coarsely 

crystalline, hard; contains lenses and bands 

of jasper; grades upward into moderatereddish-brown siltstone; forms ledge ———— 5.0

Siltstone, moderate-reddish-brown, crumbly, 

structureless; includes 1-ft-thick bed of gray 

limestone near middle; forms slope ————— 17.5

Limestone, medium-light-gray, aphanitic, 

thick-bedded (3-8 ft); contains bands of 

jasper; weathers to olive-gray; forms ledge — 17.5

Mudstone, dark-reddish-brown, fissile, very 

crumbly; contains white limy concretions, 

1-3 in. in diameter, scattered throughout; 

forms slope ——————————————————— 33.0

Mudstone, dark-reddish-brown, hard, brittle; 

forms weak rounded ledges —————————— 4.5
MEASURED STRATIGRAPHIC SECTIONS 395

Section 2—Continued 

TWENTYNINE MILE CANYON-Continued

Supai Group—Continued 

Watahomigi Formation—Continued

Conglomerate; forms prominent ledges --———— 

Matrix: crumbly to hard, moderate-reddishorange, very fine grained sandstone. 

Pebbles: white, yellowish-gray, and paleorange chert; angular to subrounded; 

mostly 0.5-1 in. in diameter; maximum 

diameter 3 in.

Feet

12.0

Total Watahomigi Formation — 150.5 

Total Supai Group ———————— 819.5

Unconformity:

Unconformity assumed; surface seems even

and flat in area observed. 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, yellowish-gray, very fine grained, 

thin-bedded (0.5-2 ft); forms receding ledges 

at rim of canyon ——————————— Not measured

Feet

1.0

Section 3—Continued 

EMINENCE FAULT—Continued

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope unit—

Continued

Mudstone, deep-red-brown; weathers to spheroidal surface; forms recess ————————

Sandstone, grayish-orange-pink; very fine 

grained; flat-bedded to cross-stratified on 

small to medium scale; some wavy beds; 

forms cliff ———————————————————— 38.5

Mudstone, deep-red-brown; weathers to spheroidal surface; forms recess —————————— 3.0

Siltstone, very pale red, very limy, hard; contains wedge- and tabular-planar crossstratification; forms cliff ———————————— 13.0

Sandstone, moderate-red-orange, very fine 

grained, calcareous (25 percent), mediumbedded (2-3 ft), flat-bedded; forms receding 

ledges —————————————————————— 14.0 

Total upper cliff-slope unit,

Esplanade Sandstone ————— 129.0

Section 3 

EMINENCE FAULT

[Along east side of Eminence Fault in Marble Canyon, east wall]

Feet

Hermit Shale:

Siltstone and mudstone, light-red-brown to 

red-brown; forms series of weak ledges 

separated by thin slopes ——————————— 28.5 

Contact:

Horizontal surface, where exposed, between 

relatively weak beds of Hermit Shale and 

underlying massive beds of Supai. 

Supai Group:

Esplanade Sandstone, upper cliff-slope unit:

Siltstone, pale-red; silt (70 percent), includes 

some very fine grained sand, calcareous (33 

percent); contains thin (1-3 ft), flat beds near 

base, weakly laminated and cross-laminated; upper part very massive and resistant; forms rounded cliff ——————————— 28.5 

Sandstone, pale-red, very fine grained; consists of thin, flat beds below and rounded 

massive above like overlying unit —————— 31.0

Esplanade Sandstone, main cliff unit:

Sandstone, pale-red, very fine grained, resistant, massive; forms cliff —————————— 30.5

Mudstone, deep-red-brown, structureless,

brittle; forms thin bench ———————————— 2.0

Sandstone, light-olive-gray, very fine grained, 

massive; contains wedge-planar crossstratification throughout; forms cliff ————— 33.5

Siltstone, pale-red, structureless; some finegrained sand; weathers to rounded surface, 

forms recess in cliff ——————————————— 2.5

Sandstone, very pale red, silty, massive; contains weakly developed cross-stratification; 

weathers to black face; forms major cliff —— 47.0

Sandstone, moderate-red-orange, very fine 

grained, thin-bedded (1-3 in.), flat-bedded; 

forms cliff continuous with units above and

DClO AAf ——————————————————————————————————— O. O

Sandstone, pale-red-brown, very fine grained; 

some silt, massive; contains weakly developed cross-stratification; weathers to black 

face; forms cliff ————————————————•

Siltstone, very pale orange to reddish-brown, 

sandy, massive, calcareous, thick-bedded 

(4 ft), cliff-forming ————————————

Mudstone, dark-reddish-brown, silty, crumbly; 

forms ledge or recess in cliff ————————

16.5

13.0

4.0
396 THE SUPAI GROUP OF GRAND CANYON

Section 3—Continued 

EMINENCE FAULT-Continued

Feet

Supai Group—Continued

Esplanade Sandstone, main cliff unit—Continued 

Sandstone and sandy siltstone, grayish-orangepink to moderate-orange-pink, very fine 

grained, massive, limy (30 percent), thickbedded (4-10 ft); contains tabular-planar 

cross-stratification, medium to large scale; 

weathers red-brown; forms sheer cliff ———— 34.0 

Total main cliff unit, Esplanade

Sandstone ——————————— 191.5

Esplanade Sandstone, basal slope unit:

Mudstone, pinkish-gray, brittle, crumbly,

slope-forming ————————————————— 38.5 

Conglomerate and conglomeratic limestone, 

pale-reddish-brown to medium-light-gray, 

ledge-forming ————————————————— 3.0 

Matrix: limestone.

Gravel: olive-gray and medium-gray limestone; reddish-brown siltstone; mostly 

0.25-0.5 in. diameter, 3 in. maximum; 

well-rounded. ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 41.5

Total Esplanade Sandstone ——— 362.0

Wescogame Formation, slope unit:

Largely concealed, slope: locally moderatereddish-brown, shaly siltstone; includes 

several thin (1-ft) ledges of medium-lightgray limestone —————

Total slope

Formation

unit, Wescogame

18.5

18.5

Wescogame Formation, cliff unit:

Sandstone, pale-reddish-brown, very calcareous, very fine grained, silty, massive; forms 

two thick beds (8-12 ft) forming cliff with 

prominent recess in middle ——————————

Siltstone, red-brown; thin flat beds with one 

thick bed (3-4 ft); similar to underlying unit; 

forms slope with one ledge ——————————

Sandstone, pale-red, very fine grained, weakly 

cross-stratified; forms rounded ledge, base 

of cliff unit ———————————————————

Sandstone, pale-reddish-brown to moderatereddish-orange, very silty, platy to nodular 

and brittle; contains two ledges of mediumbedded (2-ft) flat-bedded siltstone (81 percent silt), very limy (50 percent); forms long

17.5

23.0

14.5

Section 3—Continued 

EMINENCE FAULT-Continued

Feet

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued 

Sandstone, moderate-reddish-orange, finegrained, hard; weathers to red-brown or 

black surface; forms resistant ledge ————— 14.0 

Total cliff unit, Wescogame

Formation ——————————— 114.0

Total Wescogame Formation —— 132.5 

Manakacha Formation, slope unit:

Siltstone, pale-red, friable; contains weak 

ledge of nodular siltstone in middle; forms 

slope — •- —————— ——————— — . — _ —— j_j) f \j

Sandstone, pale-red, very fine grained, thickbedded (2-4 ft), cross-stratified, calcareous; 

like cliff below ————————————————— 7.5

Limestone, pale-red, silty (20 percent), thinbedded (1-3 in.); forms bench or slope ——— 5.5

Sandstone, grayish-red, very fine grained, very 

limy, thick-bedded (2-4 ft); includes beds of 

pale-red, cross-stratified siltstone, and one 

of light-gray limestone; forms cliff —————— 37.5

Siltstone, moderate-reddish-brown to palereddish-brown, very limy (49 percent), 

sandy, platy; contains three weak ledges of 

thin-bedded sandstone; forms long slope —— 44.0

Sandstone, moderate-orange-pink to pale-red, 

very fine grained, some fine-grained, very 

sandy, hard; forms rounded white ledge near

Siltstone, red-brown, shaly ——————————— 2.0

Total slope unit, Manakacha

Formation 

Manakacha Formation, cliff unit:

Sandstone, moderate-reddish-brown, fine- to 

medium-grained, friable; cross-stratified on 

medium scale to structureless; forms conspicuous ledge 

Sandstone, red-brown, very fine grained to 

fine-grained, shaly, slope-forming; includes 

one bed (1.5 ft thick) of dark-red-brown silt115.5

7.5

11 J.JL.Vfl 

C\ 

. \j

Sandstone, moderate-orange-pink, finegrained thick-bedded (2-10 ft); includes flatlying laminae and large-scale tabular-planar 

cross-laminae (dip 20° SW); contains abundant sand concretions (0.25 in. diameter); 

weathers to cliff, dark-brown or black ———

Limestone, grayish-red, locally light-olivegray, aphanitic, medium-bedded (1-2 ft); 

forms receding ledges or weak cliff —————

25.0

8.5
MEASURED STRATIGRAPHIC SECTIONS 397

Feet

4.0

Section 3 — Continued 

EMINENCE FAULT-Continued

Supai Group — Continued 

Manakacha Formation, cliff unit — Continued 

Concealed bench ————————————————— 

Siltstone, grayish-orange-pink, very limy; contains foraminifers; includes sand, palereddish-brown, very fine grained, calcareous; hard, thick-bedded (2-4 ft), flatbedded; forms major cliff ——————————— 

Mudstone, pale-red to dark-reddish-brown, 

structureless, silty; weathers to conchoidal 

surface; forms recess in cliff —————————— 

Siltstone, pale-red, very thin bedded, flatbedded; uniform texture; forms weak cliff — ____ 

Total cliff unit, Manakacha

Formation ——————————— 115.5 

Total Manakacha Formation —— 231.0 

Watahomigi Formation:

Mudstone, moderate-reddish-brown, silty, 

brittle, crumbly; forms slope; much conLimestone, light-olive-gray and grayish-red, 

aphanitic, medium-bedded (2-3 ft); contains 

a massive pale-reddish-brown siltstone bed 

in middle; contains jasper lenses; forms

——————————— —————————— —————————— \_2* . \j

Section 3—Continued 

EMINENCE FAULT-Continued

Feet

39.0

2.0 

18.5

Siltstone, red-brown, shaly, crumbly; forms

Limestone, light-olive-gray with dark-reddishbrown blotches, aphanitic; contains jasper 

lenses and abundant dark-gray structures, 

possibly algal; forms ledge ——————————

Siltstone, pale-reddish-brown, thin-bedded 

(1-3 in.) to shaly, flat-bedded, friable; forms 

weak ledge ——————————————————

Largely concealed slope: probably mostly 

grayish-red, shaly siltstone; contains one 

thin ledge (1 ft) of red-brown, aphanitic 

limestone (17 percent insoluble) ———————

Limestone, pale-red, locally light-olive-gray, 

aphanitic, resistant; lower part is silty with 

wavy laminae and lime nodules; upper part 

even-grained with crosscutting jasper bands;

Supai Group—Continued 

Watahomigi Formation—Continued

Concealed slope ————————————————— 10.0 

Limestone, grayish-red, with light-olive-gray 

bands; aphanitic; contains streaks of redbrown mudstone ———————————————— 3.0 

Siltstone, purple, shaly to thin-bedded; forms

slope with weak ledges ———————————— 21.0 

Conglomerate, dusky-red-purple, with moderate-orange-pink spots; ledge-forming ———— 8.5 

Matrix: brown silt.

Pebbles: siltstone and limestone; rounded to 

sub-angular; maximum 2 in., average 

0.25-0.5 in. diameter.

Siltstone, grayish-red, shaly, slope-forming —— 11.0 

Total Watahomigi Formation — 135.0 

Total Supai Group ———————— 860.5

Unconformity: Assumed. 

Redwall Limestone: 

Horseshoe Mesa Member: 

Limestone, yellowish-gray, aphanitic, mediumbedded.

Section 4 

BLUE SPRING

[Along the trail to Blue Spring]

Feet

3.0

11.0

13.0

Limestone, pale-red and light-olive-gray 

banded, aphanitic, silty, medium-bedded 

(1-2 ft); includes shaly mudstone partings; 

contains irregular lenses and bands of jasper 

and light-gray worm-shaped structures, 

possibly algal; forms receding ledges and 

siopc —— ———»—— ————————— ——————————

Coconino Sandstone.

Contact.

Hermit Shale:

Sandstone, moderate-reddish-orange, very fine

grained, silty, hard, thick-bedded (4-20 ft);

weathers to black varnished surface; forms

Siltstone, moderate- to dark-reddish-brown; 

yellowish-gray spots, shaly to structureless; 

forms recess under cliff ———————————

Conglomerate, intraformational; forms ledge —

Matrix: siltstone, moderate-reddish-brown.

Pebbles: limestone, grayish-orange-pink,

and moderate- to pale-reddish-orange and

moderate-reddish-brown siltstone.

Mudstone, dark-reddish-brown, structureless;

weathers to rounded surface; forms slope or

25.0

7.5 

2.0

recess

• \j

Conglomerate, intraformational; contains 

many cavities forming geodes; forms ledge —

14.0

4.0
398 THE SUPAI GROUP OF GRAND CANYON

Section 4—Continued 

BLUE SPRING-Continued

Feet

Hermit Shale—Continued

Conglomerate—Continued 

Matrix: gray limestone. 

Pebbles: gray limestone and moderatereddish-brown to dark-reddish-brown 

siltstone; mostly 0.25-0.5 in. in diameter, 

maximum 1 in. 

Mudstone, moderate-reddish-orange, shaly or

very weakly bedded; forms slope ——————— 47.0 

Siltstone, moderate-reddish-orange, limy;

forms bench ——————————————————— 3.0 

Mudstone, moderate-reddish-brown, structureless, medium-bedded (1-2 ft); weathers to 

rounded surfaces; forms slope ———————— 22.0 

Total Hermit Shale —————— 124.5

Contact, Hermit Shale—Supai Group. 

Supai Group: 

Esplanade Sandstone, main cliff unit:

Sandstone, moderate-reddish-orange, very fine

grained, hard; forms upper part of cliff ——— 49.5 

Mudstone, moderate-reddish-brown, very

limy, silty, structureless; forms slope ———— 18.5 

Sandstone, moderate-reddish-orange, very fine 

grained; structureless to weakly cross-stratified; thick-bedded (2-10 ft); forms cliff ——- 65.5 

Siltstone, moderate-reddish-brown, irregularly 

bedded, limy; weathers to rounded concretionary surface; forms weak ledge —————— 6.5 

Sandstone, moderate-reddish-orange, very fine 

grained, structureless to weakly crossstratified, thick-bedded (2-10 ft); forms cliff - 65.5 

Siltstone, red, flat-bedded, thin-bedded (2-

4 in); forms cliff ———————————————— 18.0 

Sandstone, moderate-reddish-orange, very fine 

grained (subangular), calcareous, structureless to weakly cross-stratified, thick-bedded 

(2-10 ft); forms cliff ——————————— 22.0

Total main cliff unit, Esplanade

Sandstone ——————————— 245.5

Esplanade Sandstone, basal slope unit:

Siltstone, moderate-reddish-brown, shaly siltstone; forms prominent bench ———————— 16.0 

Total basal slope unit, Esplanade

Sandstone ——————————— 16.0

Total Esplanade Sandstone ———

Wescogame Formation, slope unit:

Limestone, pale-red, silty, platy, and moderate 

reddish-brown, shaly siltstone; slope-forming

261.5

16.5

Feet

3.0

19.5

30.5

66.0

5.5 

4.0

Section 4—Continued 

BLUE SPRING—Continued

Supai Group—Continued

Wescogame Formation, slope unit—Continued 

Shale, red-brown; forms recess ————————— 

Total slope unit, Wescogame 

Formation ——————————— 

Wescogame Formation, cliff unit:

Sandstone, very pale orange, very fine grained, 

prominently cross-stratified; forms sheer 

cliff ________________ ._____.________..__.__„„„___—..

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, thick-bedded (2-6 ft); 

very resistant; weakly cross-stratified locally; contains large shrinkage cracks; parting 

beds of dark-reddish-brown, structureless 

mudstones form recesses as much as 4 ft 

thick; weathers to black varnished surface; 

forms sheer cliff ———————————————— 

Siltstone, red, structureless; forms slope ———— 

Conglomerate, forms weak ledge ———————— 

Matrix: moderate-reddish-brown siltstone. 

Pebbles: gray limestone and some moderatereddish-brown siltstone; well-rounded, 

mostly 0.25-0.5 in. in diameter, maximum 

diameter 3 in.

Total cliff unit, Wescogame 

Formation ———————————_ 

Total Wescogame Formation —— 

Manakacha Formation, slope unit:

Siltstone, moderate-reddish-brown, structureless; includes weak ledges of nodular limestone, each 2-3 ft thick; total forms slope —— 

Siltstone, structureless; single bed; forms 

ledge —————————————————————— 

Mudstone, deep-red, structureless, brittle; 

forms slope ——————————————————— 

Sandstone, very pale orange, fine-grained, 

thick-bedded (3-6 ft); contains planar crossstratification on medium scale; weathers 

yellow, locally with black varnish; forms 

resistant ledge ————————————————— 

Siltstone, light-brown; contains concretionary 

limestone masses; forms slope with weak

Siltstone, moderate-reddish-orange, very limy,

medium-bedded (1-3 ft); forms ledge ————

Concealed slope —————————————————

Sandstone, pale-reddish-orange, very poorly

sorted, friable; forms ledge ——————————

Concealed slope —————————————————____

Total slope unit, Manakacha

Formation ——————————— 114.5

106.0

125.5

38.5

5.5 

2.0

12.0

12.0

7.5 

28.0

2.0 

7.0
MEASURED STRATIGRAPHIC SECTIONS 399

Section 4—Continued 

BLUE SPRING—Continued

Feet Feet

Supai Group—Continued

Manakacha Formation, cliff unit:

Siltstone, moderate-reddish-orange, limy, 

medium-bedded (1-3 ft); structureless in 

lower part, cross-stratified in upper part; 

forms weak cliff ———————————————— 13.5

Siltstone, reddish-brown; contains nodules of 

light-gray limestone throughout; forms 

weak ledge and slope ————————————— 8.0

Sandstone, very pale reddish-brown, very 

fine grained (many scattered fine grains), 

thin-bedded (3-5 ft), calcareous; includes 

partings of deep-red structureless mudstone; 

contains abundant small (0.25-0.5 in.) fragments of jasper and chert scattered throughout; forms cliff ————————————————— 6.0

Limestone, olive-gray and pale-orange, dolomitic, very fine to fine-grained; contains 

abundant thin jasper layers and probable 

stromatolite structures; forms cliff —————— 7.0

Sandstone, very pale red, very fine grained, 

thick-bedded (3-5 ft); contains partings and 

thin (0.5-1 ft) layers of pale-reddish-brown, 

laminated mudstone; forms cliff ——————— 27.5

Limestone, dark-reddish-brown, nodular, 

silty; alternates with pale-reddish-brown 

mudstone; total forms slope with one weak 

ledge near middle ——————————————— 17.0

Siltstone, moderate-reddish-orange, calcareous,

sandy (43 percent); medium-bedded (2-3 ft)

at base, thick-bedded (6 ft) in middle; forms

massive cliff ——————————————————— 29.5

Total cliff unit, Manakacha

Formation ——————————— 108.5 

Total Manakacha Formation —— 223.0

2.0

—- 4.0

10.0

6.5

49.5

1.0 

14.5

Watahomigi Formation, upper slope unit:

Mudstone, moderate-reddish-brown, structureless; forms recess ———————————————— 

Concealed slope ————————————————— 

Conglomerate and dolomitic limestone, palereddish-brown, very fine grained; pebbly in 

part; locally massive; contains much red siltstone throughout as matrix between pebbles 

and as lenses; forms ledges ——————————_ 

Total upper slope unit, Watahomigi Formation ——————— 25.5

Watahomigi Formation, middle cliff and lower 

slope units:

Siltstone, reddish-brown; forms slope; largely 

concealed ———————————————————— 7.5

10.0

Section 4—Continued 

BLUE SPRING-Continued

Supai Group—Continued

Watahomigi Formation, middle cliff and lower 

slope units—Continued

Limestone, grayish-red, very finely crystalline,

silty; contains thin jasper layers and lenses of

red mudstone; forms ledge ——————————

Mudstone, reddish-brown; forms slope; largely

concealed ———————————————• 

Siltstone, pale-reddish-brown, very limy, 

shaly; contains abundant spheroidal limy 

concretions, 0.25-0.75 in. in diameter, with 

shaly siltstone wrapped around concretions; 

forms resistant ledge —————————————— 

Siltstone, conglomeratic, moderate-reddishbrown, structureless, crumbly; contains 

many gray limestone pellets, 0.25-0.5 in. in 

diameter, and tubular structures; forms 

weak ledge ——————————————————— 

Mudstone, reddish-brown, shaly; forms slope; 

mostly concealed ———————————————— 

Total middle cliff and lower 

slope units, Watahomigi Formation ————————————— 79.5 

Total Watahomigi Formation — 105.0 

Total Supai Group ———————— 715.0

Unconformity:

Surface not exposed, but limestone pebbles, 

which are light gray, dark gray and black, 

occur near contact. 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, dark-reddish-brown, very finely 

crystalline, thin-bedded (1-2 ft); forms top 

of cliff ——-—————————————— 15.5

Section 4a 

HORSETRAILCANYON

[At Little Colorado River, 0.5 mile downstream from Waterhole Canyon]

Feet

Coconino Sandstone:

Sandstone, very pale orange, fine-grained, 

cross-stratified on large scale; forms vertical 

cliff ——————————————————— Not measured

Sandstone, very pale orange, fine-grained, 

laminated, horizontally bedded; forms base 

of cliff ———————————————— 9.0

Contact:

Flat, even surface.
400 THE SUPAI GROUP OF GRAND CANYON

Section 4a—Continued 

HORSETRAIL CANYON-Continued

Hermit Shale:

Siltstone, pale-reddish-brown, weakly bedded; 

locally shaly; contains small conglomerate 

lens near middle; weathers to rounded 

knobs; forms recess below Coconino cliff ——

Conglomerate, red-brown, thin-bedded (1-

2 ft), flat-bedded; forms weak ledge —————

Gravel: mostly pale-gray, silty limestone,

some red-brown siltstone, rounded;

average 0.12-0.25 in.; maximum 0.75 in.

Matrix: red-brown siltstone.

Mudstone, dark-reddish-brown to moderatereddish-orange, coarse, silty, rubbly; contains cream-colored nodules throughout; 

forms slope with one resistant ledge of structureless siltstone ————————————————

Sandstone, pale-reddish-brown, very fine 

grained, calcareous (20 percent), shaly to 

medium-bedded; forms slope and thin weak 

ledge, and pale-reddish-brown mudstone, 

brittle, slope-forming —————————————_ 

Total Hermit Shale ———————

Section 4a—Continued 

HORSETRAIL CANYON-Continued

Feet Feet

9.0

2.0

38.5

26.5

76.0

Contact:

Horizontal surface where exposed, between 

weak beds of Hermit Shale and more massive beds of Supai below. 

Supai Group: 

Esplanade Sandstone, main cliff unit:

Sandstone, light-brown, very fine grained; 

contains prominent crossbedding etched on 

surface; forms small cliff ——————————— 16.0

Sandstone, moderate-orange-pink, very fine 

grained, friable, very thin bedded (1-3 in.) 

to shaly; includes several thin beds of gray, 

structureless siltstone; forms bench or slope 

with thin ledges ———————————————— 61.5

Sandstone, pale-red-brown, very fine grained 

(81 percent), calcareous (35 percent); contains wedge-planar cross-stratification, 

small-scale (6-30 in.) in lower part, mediumscale (3-10 ft) above; weathers with black, 

varnished surface; forms cliff consisting of 

two massive ledges ——————————————— 21.0

Siltstone, pale-reddish-brown to light-brown, 

limy (45 percent), thin-bedded to shaly; 

detritus (88 percent silt); forms slope and 

weak ledges; includes two thin units of friable, light-red-brown sandy siltstone that 

forms resistant ledges near middle and at 

top ——————————————————————— 29.0

Supai Group — Continued 

Esplanade Formation, main cliff unit — 

Continued

Sandstone, grayish-orange, fine-grained, 

prominently cross-stratified (tabular-planar 

and wedge-planar), very thick bedded (15- 

30 ft); weathers dark gray to black; forms 

cliff _ —— _ ——— ._ — ... __ — - ———— — — — . 44.0

Sandstone, moderate-orange-pink, finegrained; composed of series of very thick 

(5-15 ft), structureless beds; very resistant; 

weathers to varnished surface; forms vertical

Sandstone, pale-reddish-brown, very fine 

grained; flat bedding weakly developed; 

forms cliff ———————————————————— 4.5 

Siltstone, moderate-red, limy; laminated 

throughout; weathers dark brown; forms 

base of main cliff ———————————————— 6.5 

Total main cliff unit, Esplanade

Sandstone ——————————— 221.0

Esplanade Sandstone, basal slope unit:

Siltstone, dark-red-brown, shaly, wavybedded, slope-forming ———————————— 7.5 

Sandstone, pale-red, very fine grained; silty 

(29 percent), calcitic dolomite (28 percent); 

medium-bedded (1-3 ft); forms receding 

ledges or slope ————————————————— 6.5 

Total basal slope unit, Esplanade

Sandstone ——————————— 14.0 

Total Esplanade Sandstone ——— 235.0

Wescogame Formation, slope unit:

Siltstone, pale-reddish-brown, shaly, wavybedded, slope-forming ———————————

Concealed: slope-forming ———— 

Total slope unit,

7.0 

11.0

Wescogame

Formation — 18.0

Wescogame Formation, cliff unit:

Sandstone, grayish-orange, very fine grained; 

contains wedge-planar cross-stratification, 

medium to large scale (5-15 ft); sets very 

thick (5-15 ft); forms massive cliff —————— 66.0

Siltstone, light-brown, locally red-brown, 

thin-bedded (2-12 in.); forms slope with 

weak ledges at base of main cliff ——————— 11.0

Siltstone, grayish-red, argillaceous; basal 2 ft 

structureless, upper part shaly; forms weak 

cliff or slope —————————————————— 10.0
MEASURED STRATIGRAPHIC SECTIONS 401

Section 4a—Continued 

HORSETRAIL CANYON-Continued

Section 4a—Continued 

HORSETRAIL CANYON-Continued

Feet Feet

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued 

Sandstone, pale-reddish-brown, very fine 

grained, muddy (20 percent), very thin to 

thin-bedded (0.5-12 in.); forms slope with 

weak ledges ————————————————— 11.0 

Conglomerate, pale-red-brown; red-brown 

pebbles etched in prominent relief; weathers 

to dark-gray; forms weak receding ledge and 

fills channel in underlying resistant siltstone ————————————————————— 2.0-10.0 

Gravel: largely light-gray to light-red-brown 

siltstone and silty limestone, some deepred-brown mudstone; subangular to subrounded; closely packed; average 0.5-2 

in.; maximum 8 in.; elliptical to rectilinear.

Matrix: red-brown siltstone or sandstone. ____ 

Total cliff unit, Wescogame

Formation ——————————— 108.0 

Total Wescogame Formation —— 126.0

Manakacha Formation, slope unit:

Siltstone, grayish-red; includes much coarse 

silt; beds thin (1-2 ft) to very thick (4-5 ft), 

irregular; spheroidal weathering locally; 

forms gentle slope or receding thick ledges — 36.5

Sandstone, grayish-orange-pink, very fine 

grained, limy, thick-bedded (2-3 ft); 

weathers red-brown to yellow-brown; forms 

resistant ledge ————————————————— 5.5

Siltstone, pale-reddish-brown to moderatereddish-brown; includes much coarse silt; 

shaly to blocky; forms slope or recess ———— 3.5

Siltstone, pale-reddish-brown to moderatereddish-brown; contains gray calcareous 

concretions; weathers dark-gray; forms resistant ledge with pebble surface ——————— 2.0

Sandstone, moderate-orange-pink, finegrained, limy, cross-stratified; weathers with 

black varnish; forms resistant ledge ————— 5.5

Siltstone, very pale orange; coarse silt; contains wavy (ripple) laminae; forms recess —— 3.0

Sandstone, grayish-orange-pink, fine-grained; 

contains medium-scale (5-10 ft) cross-strata, 

wedge-planar type; forms resistant ledge —— 3.5

Siltstone, very pale orange, shaly, calcareous; 

forms slope or recess —————————————— 3.0

Supai Group—Continued 

Manakacha Formation, slope unit—Continued 

Sandstone, grayish-orange, fine-grained, calcareous; cross-stratified on medium to large 

scale (10-20 ft), tabular-planar; forms series 

of resistant ledges ——————————————— 11.5 

Total of Manakacha Formation

exposed ———————————— 74.0 + 

Total Supai Group ———————— 435.0 + 

Base of unit concealed by talus near floor of Little 

Colorado River Gorge.

Section 5 

BUNKER TRAIL

[Along west side of Bunker Trail (locally called Tanner Trail) below 

Lipan Point]

Feet

Hermit Shale:

Mudstone, pale-reddish-brown, silty; forms

slope between weak ledges. 

Supai Group:

Esplanade Sandstone, upper cliff-slope unit: 

Sandstone, light-red, very fine grained, noncalcareous, sugary; forms cliff ———————— 16.5 

Mudstone, dark-red, thin-bedded, flat-bedded,

slope-forming ————————————————— 5.5 

Sandstone, light-brown, very fine grained;

noncalcareous, sugary; forms ledge ————— 15.5 

Mudstone, dark-red, sandy, thin-bedded, flatbedded, slope-forming ———————————— 11.0 

Sandstone, light-brown, very fine grained, calcareous, sugary; forms ledge ————————— 3.5 

Mudstone, dark-red, sandy, thin-bedded, flatbedded, slope-forming ———————————— 5.5 

Conglomerate, pale-reddish-brown; contains 

rounded limestone pebbles, average 0.25 in.; 

locally distributed in channels ———————— 0-3.0 

Total upper cliff-slope unit,

Esplanade Sandstone ————— 60.5 

Erosion surface: local channeling in massive

sandstone of the Esplanade. 

Esplanade Sandstone, main cliff unit:

Sandstone, pale-orange, very fine grained, calcareous, hard; cross-laminated on large 

scale; weathers pale reddish-brown; forms 

massive cliff —————————————————— 86.5
402 THE SUPAI GROUP OF GRAND CANYON

Section 5 — Continued 

BUNKER TRAIL-Continued

Supai Group — Continued 

Esplanade Sandstone, main cliff unit — 

Continued 

Siltstone, pale-reddish-brown, friable; forms

Section 5—Continued 

BUNKER TRAIL—Continued

Feet

42.0

22.0

11.5

Sandstone, pale-orange, fine- to very fine 

grained, noncalcareous; cross-laminated on 

large scale; forms massive cliff ————————

Siltstone, pale-reddish-brown, irregularly bedded; forms weak cliff; less massive than 

underlying sandstone —————————————

Sandstone, pale-orange, very fine grained, 

calcareous, cross-laminated; forms massive

Sandstone, pale-red, very fine grained, very 

calcareous; with thin, wavy, argillaceous 

laminae of same color; weathers pale-red 

with pale-reddish-brown laminae etched 

out; forms cliff base —————————————— 

Total main cliff unit, Esplanade

Sandstone ——————————— 195.5

Esplanade Sandstone, basal slope unit:

Mudrock, pale-reddish-brown, friable; forms

conspicuous recess ——————————————— 2.0 

Siltstone, dark-brown, thick-bedded (2-4 ft);

forms ledge ——————————————————— 10.0 

Sandstone, pale-orange, very fine grained, calcareous; forms massive cliff —————————— 8.5 

Siltstone, pale-reddish-brown, argillaceous; 

lower beds hard, upper two beds softer; 

weathers same color; forms massive cliff —— 31.0 

Sandstone, white, fine-grained; forms ledge;

weathers black and dark-brown ——————— 1.5 

Conglomerate, ledge-forming; basal contact

with sandstone sharp but undulating ———— 16.5 

Matrix: pale-reddish-brown silt, calcareous. 

Gravel: size-average 0.5 in., maximum 4 in. 

in diameter; shape, rounded; composition, medium-gray limestone and palereddish-brown siltstone. ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 69.5 

Total Esplanade Sandstone ——— 325.5

Erosion surface: channel 4 ft deep and 50 ft 

wide cut in underlying siltstone.

Supai Group—Continued

Wescogame Formation, slope unit:

Siltstone, pale-reddish-brown, calcareous

(soluble 20 percent); includes limestone lenses

with irregular siliceous (organic?) particles;

much concealed; forms slope ————————— 43.0

Total slope unit, Wescogame

Formation ——————————— 43.0

Wescogame Formation, cliff unit:

Limestone, dark-reddish-brown, silty (30 percent), partly laminated and partly structureless, alternating with grayish-orange-pink, 

fine-grained (73 percent), hard sandstone; 

noncarbonate cement; average thickness of 

sets 5-15 ft; forms series of receding ledges — 63.5

Siltstone, pale-red-brown, muddy, slightly calcareous, crumbly; includes limestone concretions, light-gray, sublithographic, with 

problematic structures (organic?); forms 

slope ——————————————————————— 6.5

Sandstone, pale-reddish-brown, calcareous, 

fine- to very fine grained (rounded), crossbedded at one-third above base; interbedded 

with few thin shaly beds; forms major cliff — 57.5

Limestone, pale-red-brown, very fine grained, 

insoluble (20 percent), nodular; lower part 

argillaceous, upper part contains traces of 

organisms(?); forms recess in major cliff ——— 2.0

Siltstone, grayish-red, sandy, noncalcareous, 

structureless; sets 2-5 ft thick; basal beds 

contain limestone balls and pellets in redbrown mudstone; forms cliff ————————— 17.0

Conglomerate, pale-grayish-brown; pockets 

filled with well-rounded pebbles of limestone ———————————————————————————-"~~— u—j., u

Total cliff unit, Wescogame

Formation ——————————— 147.5 

Total Wescogame Formation —— 190.5

Manakacha Formation, slope unit: 

Mudstone, pale-red-brown, silty, slightly calcareous, irregularly bedded, crumbly; forms

2.5

3.0

Limestone, light-olive-gray, sublithographic;

weathers to rough surface; forms ledge ——— 

Siltstone, very light gray, calcareous, sandy;

forms weak ledge; partly concealed —————
MEASURED STRATIGRAPHIC SECTIONS 403

Section 5—Continued 

BUNKER TRAIL-Continued

Feet

Supai Group—Continued 

Manakacha Formation, slope unit—Continued

Siltstone, pale-red-brown, muddy; forms 

ledges 1-2 ft thick; alternates with mudstone 

beds, shaly, slope-forming; includes thin 

limestone interbeds —————————————— 5.5

Sandstone, grayish-red, slightly calcareous, 

very fine grained to silty; weathers to black 

or brown; nodular in top 2 ft; forms massive 

cliff ____________________________________________________ 13.0

Concealed ————————————————————— 2.0 

Siltstone, and sandstone, pale-reddish-brown, 

very calcareous, muddy, flat-bedded; forms 

weak ledge ——————————————————— 6.0 

Sandstone, grayish-orange-pink, calcareous, 

fine-grained; crossbedded on large scale; 

weathers locally to black surface; forms 

cliff ____________________________ 13.5

Mudstone, grayish-red, very calcareous, structureless, crumbly; contains small limestone 

nodules; forms recess—————————————— 2.0

Limestone, grayish-red, sublithographic (insoluble 27 percent); contains red, silty stringers and brown flint lenses ——————————— 3.5

Limestone, grayish-red, sublithographic; contains gray nodules; forms weak ledge ———— 1.5 

Total slope unit, Manakacha

Formation ——————————— 80.5 

Manakacha Formation, cliff unit:

Siltstone, grayish-red, very fine grained, limy 

(47 percent), muddy, very thick bedded (4- 

15 ft); forms major cliff with two underlying 

units consisting of pale-reddish-brown, 

slightly calcareous, very fine grained sandstone; cross-stratified on large scale (above 

25 ft), and pale-reddish-brown, slightly calcareous, very fine to fine-grained, very thick 

bedded sandstone ——————————————— 49.5

Sandstone, moderate-reddish-brown, very fine 

grained, noncalcareous, silty, forms weak 

ledge —————————————————————— 1.5

Sandstone, pale-reddish-brown, calcareous, 

very fine grained (rounded); weathers 

reddish-brown; forms massive ledge ————— 10.0

Limestone, pale-red, sublithographic (insoluble residue, 25 percent); contains jasper; 

weathers dark gray ——————————————— 1.5

Sandstone, moderate-reddish-brown, very fine 

grained (subrounded), muddy, slightly calcareous; forms rounded ledge ———————— 3.0

Feet

2.0

10.0

3.5

11.0

6.5 

2.0

Section 5—Continued 

BUNKER TRAIL-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Concealed —————————————————

Limestone, grayish-orange-pink, very fine 

grained (subrounded), silty, insoluble (40 

percent); crossbedded, small scale, weathers 

to black, locally jasper in the middle; forms 

ledge —————————————————————

Sandstone, pale-reddish-brown, very fine 

grained (subrounded), slightly calcareous, 

silty, structureless; forms rounded ledges ——

Siltstone, dark-reddish-brown, muddy, slightly calcareous, thin-bedded (0.25-2 in.); 

weathers to black surface; forms irregular,

Limestone, pale-red-brown, insoluble (40 percent), very fine grained (rounded); crossstratified on medium scale; locally contains 

limestone nodules; weathers to black surface; forms cliff ——————————————

Limestone, grayish-orange-pink, sublithographic; weathers to black or dark-gray surface; thick-bedded (2-5 ft); and sandstone, 

pale-red to pale-reddish-brown, very fine 

grained, very limy (47 percent); weathers to 

black or dark gray surface; thick-bedded; 

forms cliff ———————————————————— 13.5

Total cliff unit, Manakacha

Formation ——————————— 114.0

Total Manakacha Formation —— 194.5

Watahomigi Formation:

Limestone, grayish-red, mottled, silty, sublithographic, concretionary; contains jasper 

lenses and thin irregular beds (6-12 in.); 

forms ledge ——————————————————— 2.5

Siltstone, moderate-reddish-brown, slightly

j-*-j i_"'OT'O-''\11C — _____ ______ _______ _______ _*_._____ "1 C\_"1 ^

l_CU\_OJL t_.(_sU& —— — —— —__.-. _L. V -L .«_}

Limestone, grayish-red, mottled, sublithographic, concretionary; contains jasper 

lenses; forms ledge ——————————————— 4.0-4.5

Sandstone, moderate-reddish-brown, very fine

grained, structureless; forms rounded ledge — 1.0

Limestone, grayish-red, sublithographic (70 

percent insoluble); weathers to dark-gray or 

black; forms ledge ——————————————— 1.5

Sandstone, moderate-reddish-brown, very fine 

grained, silty, iron-oxide coated, structureless; forms rounded ledge ——————————— 3.0
404 THE SUPAI GROUP OF GRAND CANYON

Section 5 — Continued 

BUNKER TRAIL— Continued

Supai Group — Continued 

Watahomigi Formation — Continued

Siltstone, pale-red and pinkish-gray, very 

sandy, limy, thick-bedded (3-15 ft); weathers to black or red; locally contains small 

limestone nodules and jasper lenses; bedding 

planes weakly developed near top and bottom; mostly forms massive cliff ——————

Siltstone, grayish-red, crumbly; forms slope — —

Siltstone, pale-reddish brown, calcareous;

basal part argillaceous; contains irregular

limestone nodules (0.5-1 in. to 2-10 in.);

forms weak ledges (1-2 ft) —————————

Concealed —————————————————

Limestone, grayish-red, sublithographic; 

weathers to dark-gray or black; contains 

variegated bands of jasper; forms massive

Feet

Sandstone, pale-reddish-brown (top) and moderate-reddish-orange, calcareous, very fine 

grained, muddy, medium-bedded (1-2 ft); 

forms rounded ledge ——————————————

Siltstone, pale-reddish-brown, sandy, calcareous, thick-bedded; forms ledge — —— — ——

Mudstone, grayish-red, crumbly, brittle, limy 

(47 percent); structureless; forms slope 

(much concealed) —————————————

Sandstone, pale-reddish-brown, calcareous, 

very fine grained, silty, friable, mediumbedded (0.5-2 ft); weathers to red- or darkgray surface; forms weak ledge ———————

Limestone, grayish-orange-pink, sublithographic, silty (40 percent), medium-bedded 

(2-3 ft); weathers to dark-gray or black surface; contains irregular thin layers of jasper; 

bottom half contains abundant red mud 

balls and pellets (0.5-1 in.), also lenses (as

Claystone, pale-red, limy (39 percent), fissile;

forms slope (partly concealed) ——— —— ——

Conglomerate, pale-reddish-brown; contains

flint, quartzite and limestone pebbles; matrix

of platy very fine grained sand ————————

Total Watahomigi Formation —

Total Supai Group ————————

16.5 

1.0

4.0 

12.0

4.0 

6.0

3.0

7.5

3.0 

3.0

2.5

6.5 

7.5

0-2.0

92.5

803.0

Section 5—Continued

BUNKER TRAIL-Continued 

Unconformity:

Surface of marked relief within area of 0.5 

mile. Eastward dipping beds of the Redwall 

Limestone are beveled and form wedge 

toward northeast. 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, brownish-gray, sublithographic, 

thin-bedded (6-24 in.).

Section 6 

GRANDVIEW TRAIL

[Along Grandview Trail on west side of main ridge; 1 mile south of 

Horseshoe Mesa]

Hermit Shale:

Succession of pale-reddish-brown mudstone 

and sandstone units forming slope with a 

few weak ledges. 

Contact:

Unconformity not observed at this locality. 

Supai Group:

Esplanade Sandstone, upper cliff-slope and main 

cliff units:

Sandstone, very pale orange, very fine grained, 

silty, structureless; weathers to black surface; forms vertical face ————————• 

Siltstone, pale-reddish-brown, muddy; contains some very fine grained sand; flatbedded, very thin bedded (6 in.-l ft); forms

ItCCSS —————————————————————————————

Sandstone, very pale orange, very fine grained, 

structureless; weathers to black surface; 

forms vertical face at top of Esplanade cliff —

Siltstone, pale-reddish-brown, muddy, shaly; 

forms slope ———————————————

Sandstone, very pale orange, very fine grained, 

silty, slightly calcareous, thin-bedded (1-3 

ft); forms receding ledges ———————————

Mudstone, pale-reddish-brown, very calcareous, silty, shaly; forms slope ——————-

Sandstone, moderate-orange-pink, very fine 

grained, slightly calcareous, thin-bedded 

(1-2 ft); forms weak cliff ————————————

Sandstone, moderate-orange-pink, very fine 

grained, slightly calcareous, thin-bedded 

(1-2 ft); forms series of receding ledges, partFeet

- 5.5

4.0

23.5

- 5.0

9.5

- 6.0

26.0
MEASURED STRATIGRAPHIC SECTIONS 405

Section 6—Continued 

GRANDVIEW TRAIL-Continued

Feet

Supai Group—Continued

Esplanade Sandstone, upper cliff-slope and main

cliff units—Continued

Sandstone, moderate-orange-pink, very fine 

grained, calcareous (35 percent); very thick 

bedded (6-8 ft); commonly weathers to 

black surface; forms massive, sheer cliff ——— 16.5

Mudstone, pale-reddish-brown, calcareous, 

very thin to thin-bedded (1-6 in.); forms 

slope —————————————————————— 9.0

Siltstone, moderate-reddish-orange, hard; contains some very fine grained sand; very thick 

bedded (5-7 ft); weathers to surface of 

rounded knobs (diameters 1-2 in.); forms 

cliff —————————————————— 16.5

Mudstone, pale-reddish-brown, calcareous, 

concretionary; weathers to surface of

rounded knobs (diameters 1-2 in.); forms

cliff ________________________ 5 5

Sandstone, pinkish-gray, very fine grained, 

slightly calcareous; consists of thick, structureless beds; forms sheer cliff ———————— 8.0

Siltstone, pale-reddish-brown, shaly to thinbedded (0.25-3 in.); forms slope ——————— 14.5

Sandstone, very pale orange to moderateorange-pink, very fine grained, calcareous 

(35 percent), very thick bedded (5-20 ft); 

contains several thin, pale-reddish-brown 

mudstone parting zones; weathers to black 

surface; forms major, sheer cliff ——————— 63.5

Sandstone, pale-red, very fine grained, silty, 

calcareous, massive; weathers to black, 

rounded surface; forms resistant ledge at 

base of major cliff ——————————————— 5.5 

Total upper cliff-slope and main 

cliff units, Esplanade Sandstone —————————————— 231.5

Esplanade Sandstone, basal slope unit:

Siltstone, pale-reddish-brown, very thin bedded (2 in.), calcareous; contains Rivularites; 

forms steep slope or recess —————————— 8.5 

Concealed slope ————————————————— 42.0 

Limestone, grayish-red, silty; forms resistant

Total basal slope unit, Esplanade

Sandstone ——————————— 53.5 

Total Esplanade Sandstone ——— 285.0

Feet

11.0

15.5

33.0

Section 6—Continued 

GRANDVIEW TRAIL—Continued

Supai Group—Continued 

Wescogame Formation, slope unit:

Concealed slope ————————————————— 

Sandstone, moderate-orange-pink, very fine 

grained, calcareous (26 percent), thin- to 

thick-bedded (1-4 ft), structureless; contains 

some grayish-red mudstone partings between ledges; weathers to gray face; forms 

resistant ledges ————————————————— 

Concealed slope ————————————————— 

Total slope unit, Wescogame

Formation ——————————— 59.5

Wescogame Formation, cliff unit:

Sandstone, moderate-orange-pink, very fine 

grained (well-rounded); contains many fine 

grains; slightly calcareous; forms series of 

ledges (2-4 ft), separated by concealed slopes 

of muddy, grayish-red siltstone (2-4 ft) ———

Siltstone, pale-reddish-brown, muddy, slightly 

calcareous; bedding irregular; forms weak 

receding ledge —————————————————

Concealed slope —————————————————

Sandstone, moderate-reddish-orange (very 

pale orange at top), very fine grained, limy 

(42 percent); small- to medium-scale (8-20 

in.); cross-stratification; forms resistant 

ledge with straight face ————————————

Siltstone, grayish-red, muddy, calcareous, 

mostly concealed; contains local irregular 

bedding structures; forms weak ledges

Sandstone, pinkish-gray, very fine grained 

(subrounded to rounded); contains scattered 

fine grains; calcareous; prominently crossstratified, planar type; locally crossbeds are 

large-scale (50+ ft), elsewhere two or three 

small sets of similar cross-stratified structures, form cosets; weathers to surface of 

black varnish; forms sheer cliff ———————— 48.0

Mudstone, grayish-red, structureless; forms 

recess ——————————————————————

Siltstone, pale-reddish-brown, very calcareous, thin- to thick-bedded (1-4 ft); contains 

medium-scale, wedge-planar cross-stratification (1-3 ft); includes lime balls and pellets in 

mud matrix at base; forms base of main cliff ~ 

Total cliff unit, 

Formation ——-

34.5

9.0 

16.0

5.5

—- 18.0

2.0

9.0

Wescogame

—————— 142.0

Total Wescogame Formation —— 201.5
406 THE SUPAI GROUP OF GRAND CANYON

Section 6—Continued 

GRANDVIEW TRAIL-Continued

Supai Group—Continued

Manakacha Formation, slope unit:

Siltstone, grayish-red, muddy, calcareous, 

structureless; forms weak rounded ledges at 

base of major cliff ———————————————

Concealed slope, grayish-red, crumbly mudstone locally exposed —————————————

Siltstone, pale-reddish-brown, calcareous, 

thin-bedded (0.5-1.5 ft); contains nodular 

zones; weathers to rounded, irregular weak 

ledges and slope —————————————

Sandstone, moderate-orange-pink, very fine 

grained (subrounded); contains scattered 

fine grains; slightly calcareous; forms resistant ledges in middle of slope; unit is twice 

as thick 300 ft to south ————————————

Concealed slope —————————————

Siltstone, pale-reddish-brown, muddy, calcareous, thin-bedded (0.5-1 ft); forms slope 

and weak ledges ————————————————_ 

Total slope unit, Manakacha 

Formation —————————

Manakacha Formation, cliff unit:

Sandstone, pale-red, very calcareous, very 

thick bedded (4-8 ft); thin mudstone partings; tabular-planar cross-stratified in part; 

locally weathers to black varnish; forms 

cliff _________________________

Mudstone, grayish-red, crumbly; forms reSandstone, pale-reddish-brown, very fine 

grained; grades upward into a pale-red silty 

limestone near middle of unit and into lightbrownish-gray limestone at top of unit; 

forms rounded ledges or slope ——————— 

Sandstone, grayish-orange-pink, very fine 

grained, thick- to very thick bedded (3-5 ft), 

structureless; forms rounded cliff —————— 

Sandstone, pale-red, very fine grained, calcareous; structureless; forms bench composed of two rounded ledges, separated by 

partings of grayish-red, shaly mudstone ——— 

Sandstone, very pale orange, very fine grained; 

thick- to very thick bedded (2-8 ft); contains 

prominent, medium-scale (5-15 ft), wedgeplanar cross-stratification; forms cliff ———— 

Mudstone, grayish-red, brittle; forms recess — 

Siltstone, very pale orange, limy, very muddy, 

thick- to very thick bedded (2-8 ft); weakly 

cross-stratified; forms cliff —————————

Section 6—Continued 

GRANDVIEW TRAIL-Continued

Feet feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Limestone, grayish-red; contains spheroidal

structure; forms recess ———————————— 1.5 

5.0 Siltstone, pale-reddish-brown, calcareous, 

very hard, thick-bedded (2-3 ft); forms base 

24.0 of major sheer cliff ——————————————— 6.5 

Mudstone, grayish-red, crumbly; contains 

abundant gray limestone concretions (0.5-1 

in. diameter); forms weak ledge or slope —— 5.0 

16.5 Sandstone, moderate-orange-pink, very fine

grained; forms resistant rounded ledge ——— 4.0 

Concealed slope ————————————————— 10.0 

Sandstone, pinkish-gray, fine-grained to very 

fine grained, slightly calcareous, structure2.5 less; forms rounded ledge ——————————— 3.5 

11.0 Sandstone, moderate-reddish-orange, very

fine grained, friable; forms weak ledge ——— 5.0 

Siltstone, grayish-red, muddy, shaly; includes 

16.5 some very thin bedded (0.5-1 in.) siltstone 

containing light-gray, limy nodules; forms 

75.5 slope ——————————————————————— 8.0 

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, weakly cross-stratified; 

weathers to straight face; forms ledge ———— 4.5 

Mudstone, grayish-red, crumbly; includes one

thin bed (1 ft) of gray limestone ——————— 4.5 

Limestone, pale-red, very silty; contains nod34.0 ular structure; weathers to pale-reddishbrown surface; forms weak ledge —————— 6.5 

1.0 Sandstone, moderate-orange-pink, very fine 

grained, silty (20 percent), very limy (47 percent); contains wedge-planar cross-stratification; weathers to straight face with much 

varnish; laminae etched out; forms cliff ——— 7.0 

7.5 Concealed slope, probably much pale-reddishbrown, fissile mudstone ——————————— 3.0 

Sandstone, pale-reddish-brown, very fine 

9.0 grained, calcareous, structureless; forms

rounded ledge ————————————————— 4.0 

Limestone, pale-red, silty; contains lumps of 

pale-reddish-brown mudstone; forms 

5.0 rounded ledge ————————————————— 4.0 

Siltstone, pale-red, muddy, very calcareous, 

structureless; contains small (0.13-0.25 in.) 

limestone nodules throughout; forms weak 

15.5 rounded ledge ————————————————— 5.5 

2.0 Concealed slope ————————————————— 9.0 

Limestone, brownish-gray, aphanitic, thinbedded (0.5-2 ft); contains thin jasper 

15.5 layers; forms weak ledge ——————————— 3.5
MEASURED STRATIGRAPHIC SECTIONS 407

Section 6—Continued 

GRANDVIEW TRAIL-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Sandstone, very pale orange, very fine 

grained; slightly calcareous; mostly structureless but locally cross-stratified; contains 

scattered elongate gray limestone nodules 

(0.5-2 ft); weathers to pale-reddish-brown 

or black varnished surface; forms thick cliff 

with straight face ———————————

Siltstone, grayish-red, sandy, muddy, slightly 

calcareous, friable; forms recess ——————

Limestone, pale-red, very fine grained, silty 

(32 percent); weathers to rough surface; contains Fusulinella sp., Pseudostaffella sp.; 

forms resistant ledge ———————————

Sandstone, pale-reddish-brown, very fine 

grained, silty; grades upward into pale-reddish-brown siltstone; locally weathers to a 

black varnished surface; forms resistant, 

rounded ledge —————————————

Limestone, light-brownish-gray, muddy (22 

percent), aphanitic to very fine grained, irregularly bedded; contains thick jasper 

layer; weathers to rough surface; forms resistant ledge ————————————————

Sandstone, pale-reddish-brown, very fine 

grained, silty, slightly calcareous, structureless; weathers to conspicuous, rounded ledge 

with black varnished surface —————————

Limestone, grayish-red, silty (20 percent); contains thin jasper layers; includes limestone 

pebbles; weathers to rough surface; forms 

base of cliff unit ————————————

Total

Feet

12.0

1.5

2.0

5.5

5.5

4.5

2.5

Feet

13.0

8.5 

1.0

68.5

12.0

cliff unit, Manakacha 

Formation ——————————— 218.0 

Total Manakacha Formation —— 293.5

Watahomigi Formation, upper slope unit:

Mudstone, grayish-red, crumbly; forms slope — 6.5 

Siltstone, grayish-red, slightly calcareous, 

friable, thin-bedded (0.5-1 ft); contains 

Fusulinella sp.; forms weak ledge —————— 4.5 

Siltstone, pale-reddish-brown, thin-bedded 

(1 ft); contains much grayish-red, crumbly 

mudstone; forms slope, mostly concealed — 24.0 

Siltstone, pale-reddish-brown, muddy, thinbedded (0.5-2 ft), friable; forms weak ledge — 6.0 

Mudstone, grayish-red, crumbly; forms slope — 1.5 

Siltstone, grayish-red, very muddy, calcareous, thin-bedded (1-2 ft); forms resistant

Section 6—Continued 

GRANDVIEW TRAIL-Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit— 

Continued

Mudstone, grayish-red, brittle; forms slope ——

Siltstone, grayish-red, muddy, shaly, and

irregularly bedded; forms series of very

weak ledges and slopes ———————————

Conglomerate, grayish-red; forms ledge ——— 

Matrix: grayish-red siltstone. 

Gravel: mostly 0.16-0.25 in. diameter; maximum diameter 0.5 in.; subrounded to 

rounded pebbles; composed of greenishgray and grayish-red limestone and siltstone.

Total upper slope unit, Watahomigi Formation —————- 

Watahomigi Formation, middle cliff and lower 

slope units:

Mudstone, grayish-red, slightly calcareous, 

crumbly; forms slope ————————————

Limestone, pale-reddish brown, silty, insoluble 

(34 percent), concretionary; grades upward 

into silty (44 percent), light-gray, irregularly 

bedded limestone that contains thin jasper 

layers. Weathers into spheres (1-2 in. 

diameter); forms weak ledge ————————

Mudstone, grayish-red, brittle, and mediumlight-gray, shaly limestone; forms slope ———_ 

Total middle cliff and lower 

slope units, Watahomigi Formation ————————————— 24.5 

Total Watahomigi Formation — 93.0

Total Supai Group ———————— 873.0 

Unconformity: not observed at place of section. 

Redwall Limestone:

Horseshoe Mesa Member: 

Limestone, light-olive-gray, aphanitic; thinbedded (0.5-2 ft); cavernous.

Section 7 

KAIBAB TRAIL, SOUTH

[Along ridge extending north from Yaki Point]

Hermit Shale:

Claystone, pale-reddish-brown, shaly, thinbedded. 

Unconformity: erosion channels shallow, filled with

thin-bedded, shaly mudstone.

4.5

8.0
408 THE SUPAI GROUP OF GRAND CANYON

Section 7—Continued 

KAIBAB TRAIL, SOUTH-Continued

Feet

Supai Group:

Esplanade Sandstone, upper cliff-slope and main 

cliff units:

Siltstone, light-reddish-brown, structureless; 

beds 2-3 ft thick; forms ledge. Alternates 

with pale-reddish-brown, brittle claystone; 

forms slope; beds 2-3 ft thick. Total forms 

series of ledges and slopes ——————————— 27.5

Sandstone, moderate-orange-pink, very fine 

grained, calcareous, cross-laminated, hard; 

beds 2-6 ft thick; weathers pale-brown to 

dusky-brown; forms cliff ——————————— 25.0

Mudstone, pale-reddish-brown, structureless, 

brittle; contains 2-ft bed of resistant, very 

fine grained sandstone; forms slope ————— 15.5

Sandstone, light-brown, very fine grained, 

argillaceous, calcareous, cross-laminated, 

resistant; beds 2-6 ft thick; locally contains 

lenses of mudrock; weathers pale-reddishbrown or light-brown ————————————— 27.5

Mudstone, pale-reddish-brown, structureless,

brittle; forms slope ——————————————— 4.0

Sandstone, very pale reddish-brown to palered, very fine grained, argillaceous; crosslaminated on large scale, very resistant; bedding sets 12-30 ft thick; locally contains scattered fine- to medium-sand grains; weathers 

pale-reddish-brown or black; forms sheer 

cliff ———————————————————————— 66.0

Sandstone, very pale orange, very fine grained, 

argillaceous, silty, structureless, resistant; 

beds 2-4 ft thick; contains pale-reddishbrown, argillaceous siltstone at top; 

weathers light-brown; forms cliff ——————— 16.5

Claystone, pale-reddish-brown, structureless,

brittle; forms slope ——————————————— 2.5

Sandstone, pale-reddish-brown to reddishgray, very fine grained, calcareous, very 

resistant; beds 3-8 ft thick with parting 

planes of pale-red, calcareous claystone forming recesses; weathers same; forms cliff —— 18.5 

Total upper cliff-slope and main 

cliff units, Esplanade Sandstone —————————————— 203.0

Esplanade Sandstone, basal slope unit:

Claystone, pale-reddish-brown, structureless, 

brittle; forms slope with thin ledge of very

fine grained sandstone in middle 30.5

Section 7—Continued 

KAIBAB TRAIL, SOUTH-Continued

Supai Group—Continued

Esplanade Sandstone, basal slope unit—Continued 

Sandstone, light-reddish-brown, very fine 

grained, argillaceous, very calcareous, structureless; beds 2-4 ft thick with thin mudstone partings; weathers pale-reddishbrown, forms ledge ————————————

Claystone, light-reddish-brown, silty; thinbedded except near top; forms slope ———— 

Conglomerate———————————————

Matrix: pale-reddish-brown claystone. 

Gravel: Size—average 0.25 in., but commonly 0.5-1 in.; mostly rounded; composition—pale-reddish-brown siltstone. _ 

Total basal slope unit, Esplanade

Sandstone ———————————_ 

Total Esplanade Sandstone 

Unconformity: surface of small relief. 

Wescogame Formation, slope unit:

Claystone, pale-reddish-brown, structureless, 

silty; forms slope; contains pale-red, rubbly 

limestone at top ————————————

Sandstone, light-brown, very fine grained, 

argillaceous, very calcareous, structureless, 

hard; weathers light-brown to dark-brown;

Dolostone, calcitic, pale-reddish-brown, structureless, brittle; forms slope ———————

Sandstone, very pale orange, very fine grained, 

cross-laminated; weathers pale-reddishbrown; forms cliff ————————————

Mudstone, pale-reddish-brown, slope-forming; 

structureless, brittle, and alternating lightbrown, argillaceous, calcareous, thinbedded siltstone that forms ledges; unit 

forms series of slopes and ledges ——————

Siltstone, light-brown, argillaceous, calcareous, thin-bedded; forms ledge ———————

Claystone, pale-reddish-brown, structureless;

Limestone, pale-red, very silty; weathers palereddish-brown, silty; forms cliff —————— 

Total slope unit, Wescogame 

Formation ————————— 

Wescogame Formation, cliff unit: 

Mudstone, pale-reddish-brown, structureless, 

brittle; forms slope. Alternates with a few 

beds of sandstone that are pale-reddishbrown, very fine grained, shaly, friable, 

argillaceous sandstone; weathers same. Unit

Feet

27.5

9.0 

3.0

70.0

—— 273.0

16.5

2.0 

5.5

26.5

13.0 

2.5 

2.5 

4.0

72.5

59.0
MEASURED STRATIGRAPHIC SECTIONS 409

Section 7—Continued 

KAIBAB TRAIL, SOUTH-Continued

Supai Group—Continued

Feet

Wescogame Formation, cliff unit—Continued

Sandstone, very pale orange, very fine grained, 

calcareous, cross-laminated except at base; 

weathers pale-reddish-brown to black; 

forms cliff ———————————————————— 7.5

Claystone, pale-red spotted with yellowishgray, silty, calcareous, brittle; forms slope — 3.0

Sandstone, pale-red, very fine grained, calcareous, argillaceous, structureless; forms ledge; 

weathers very pale reddish-brown. Alternates with pale-reddish-brown, shaly, 

friable claystone. Unit forms series of ledges 

and slopes ——————————————————— 6.0

Claystone, dusky-red, brittle, structureless;

forms slope ——————————————————— 4.5

Claystone, pale-red, silty, resistant; resembles 

mud-ball structure; forms rounded ledge —— 2.0

Sandstone, very light brown, fine-grained, 

calcareous; cross-laminated on large scale, 

hard; contains large reptilian footprints; 

weathers pale-reddish-brown; forms sheer 

cliff ———______—_________________________________ 62.5

Claystone, pale-red, brittle, structureless; 

forms slope ——————————————————— 4.0

Siltstone, very pale brown, calcareous, argillaceous, structureless; forms ledge —————— 5.5

Claystone, pale-reddish-brown, silty, flatbedded; contains calcareous nodules and 

siliceous rods; forms weak, rounded ledge — 8.0

Mudstone, conglomeratic; local accumulations of rounded pebbles (light- and darkgray limestone, red-brown siltstone), mostly 

0.25-0.5 in. in diameter with matrix of darkred-brown mud that probably infiltrated 

pebble deposits ———————————————— 0.0-1.0 

Total cliff unit, Wescogame Formation —————————————163.0 

Total Wescogame Formation —— 235.5

Erosion surface: Small-scale irregularities. 

Manakacha Formation, slope unit:

Mudstone, pale-reddish-brown, brittle, structureless; forms slope; contains weak, shaly 

siltstone and limestone beds near top ———— 36.0

Siltstone, pale-reddish-brown, calcareous, 

argillaceous, structureless; forms ledge ——— 3.5

Claystone, pale-reddish-brown, structureless, 

slope-forming; interbedded with pale-red 

siltstone; beds 0.5-1 ft thick ————————— 6.5

Section 7—Continued 

KAIBAB TRAIL, SOUTH-Continued

Supai Group—Continued

Manakacha Formation, slope unit—Continued 

Sandstone, very light brown, very fine grained, 

silty, calcareous; cross-laminated on large 

scale, hard; weathers light-brown; forms

Siltstone, light-brown, argillaceous, calcareous, structureless; forms ledge; contains 

claystone at top ————————————-

Feet

9.5

- 2.0

Claystone, pale-reddish-brown, structureless, 

brittle; forms slope ——————————————— 2.0

Siltstone, light-brown, argillaceous, calcareous, structureless; forms ledge ———————— 4.0

Claystone, pale-reddish-brown, structureless, 

brittle; alternates with pale-red, calcareous, 

thin-bedded siltstone; weathers same; total 

forms slope ——————————————————— 13.0

Sandstone, very pale reddish brown, very fine 

grained, very calcareous, structureless; 

weathers moderate-brown; forms ledge ——— 2.5

Claystone, pale-reddish-brown, structureless, 

brittle; forms slope ——————————————— 2.0

Sandstone, very light brown, very fine grained, 

calcareous, locally cross-laminated; 

weathers light-brown; forms cliff —————— 11.0

Claystone, pale-red, mottled with yellowishgray; structureless, brittle; forms slope ——— 5.0

Sandstone, very light brown, very fine grained, 

calcareous, cross-laminated; weathers palereddish-brown; forms ledge —————————— 7.0

Claystone, pale-red, structureless, brittle;

Sandstone, reddish-gray, very fine grained,

argillaceous, calcareous, structureless;

weathers pale-reddish-brown; forms ledge — 3.0 

Claystone, pale-red, structureless, brittle;

forms slope ——————————————————— 6.0 

Siltstone, pale-red, argillaceous, calcareous;

forms ledge ——————————————————— 8.0 

Limestone, brownish-gray to pale-red, aphanitic, silty, irregularly bedded; weathers

rough, rounded ———————————————— 2.5 

Siltstone, pale-reddish-brown, argillaceous;

beds weakly developed, thin (0.25-0.5 in.),

irregular; forms slope ————————————— 5.5 

Siltstone, pale-red, argillaceous, calcareous,

structureless; forms ledge ——————————— 2.0 

Siltstone, pale-reddish-brown, argillaceous,

beds thin, irregular; forms slope ——————— 8.5
410 THE SUPAI GROUP OF GRAND CANYON

Section 7—Continued 

KAIBAB TRAIL, SOUTH-Continued

Supai Group—Continued

Manakacha Formation, slope unit—Continued 

Siltstone, pale-red, calcareous, weathers palereddish-brown; forms ledge ——————————_ 

Total slope unit, Manakacha 

Formation ——————————

Manakacha Formation, cliff unit:

Sandstone, very pale brown, very fine grained, 

resistant; weathers very pale reddish brown, 

mottled with pale-reddish-brown; forms

Sandstone, very pale orange, fine-grained, 

calcareous (30 percent); cross-laminated; 

contains light-brownish-gray limestone bed 

at center; weathers very pale reddish brown; 

forms prominent cliff ———————————

Limestone, light-brownish-gray, argillaceous 

(40 percent), irregularly bedded; upper surface wavy; weathers very pale reddish 

brown, clay-coated ————————————

Claystone, dusky-red with pale-yellow deoxidized patches, brittle; beds 1-3 ft thick; 

alternating with pale-reddish-brown, resistant claystone; three beds 1-2 ft thick; total 

forms series of slopes and ledges ———————

Sandstone, very pale reddish brown, very fine 

grained, calcareous; beds flat; forms ledge ——

Claystone, dusky-red, structureless, brittle;

Limestone, brownish-gray, very sandy; grades 

down into reddish-gray, calcareous siltstone; cross-laminated on large scale; total 

unit forms prominent cliff ————————

Claystone, dusky-red, structureless, brittle; 

forms slope —————————————————

Siltstone, reddish-gray speckled with yellowishwhite, calcareous; weathers very pale reddish brown; forms ledge ———————————

Claystone, pale-red, structureless, brittle; 

forms slope ———————————————————

Siltstone, pale-red, calcareous (30 percent), 

argillaceous, hard; contains lenses and thin 

beds of brownish-gray limestone; weathers 

pale-reddish-brown; forms weak cliff ————

Limestone, very pale reddish-brown, sandy, 

cross-laminated, resistant; weathers lightbrown or brownish-black with laminations

pfpnpH t LV-l It vl r\i \_/ U if* L —.—__________———,——________._——————————•.———

Sandstone, pale-reddish-brown, very fine 

grained, structureless, friable; weathers 

same; forms slope —————————————

Feet

2.5

feet

147.5

2.5

40.5

2.0

11.0 

6.0 

4.5

18.5

11.0

2.5 

10.0

13.0

2.5 

2.0

Section 7—Continued 

KAIBAB TRAIL, SOUTH-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Limestone, reddish-gray to brownish-gray, 

aphanitic, pebbly; intermixed with deep-redclaystone; weathers pale-reddish-brown, 

clay-coated; forms slope ———————————

Siltstone, pale-red, calcareous, structureless, 

hard; contains limestone inclusions —————

Claystone, dusky-red, structureless, brittle; 

forms slope ——————————————

Claystone, pale-reddish-brown; beds thin and 

flat; forms massive ledge grading down into 

weak cliff or slope ———————————————

Claystone, pale-reddish-brown, structureless, 

brittle; forms slope ———————————————

Limestone, brownish-gray; contains thin layers 

of jasper; weathers with wavy silt laminae 

etched out; forms ledge ——————————

Siltstone, light-reddish-brown, argillaceous, 

friable; contains limestone concretions; 

forms slope —————————————————

Claystone, pale-red, structureless, shaly; forms 

slope ———————————————————

Limestone, brownish-gray, aphanitic; contains 

lenses of dark-reddish-gray siltstone near 

base; weathers light-olive-gray; forms ledge —

Sandstone, light-reddish-brown, very fine 

grained, argillaceous, friable; forms slope ——

Limestone, brownish-gray, aphanitic; grades 

upward into dark-reddish-gray siltstone; 

contains jasper lenses; forms ledge ——————

Sandstone, light-reddish-brown, very fine 

grained, friable; forms slope ————————

Limestone, brownish-gray, aphanitic; weathers light-olive-gray; forms ledge -—————

Sandstone, reddish-gray speckled with very 

light brown, very fine grained, calcareous, 

structureless; weathers pale-reddish-brown, 

rounded ledge ———————————————

Limestone, brownish-gray, aphanitic; weathers 

light-olive-gray; contains jasper lenses ————

Siltstone, pale-red, argillaceous, friable; forms 

slope ———————~—

Claystone, pale-red, structureless; forms 

rounded ledge ————————————————

Limestone, pale-reddish-brown, silty (15 percent); weathers massive; grades into underlying unit ———————————————————^

Total cliff unit, Manakacha Formation —————————————190.5 

Total Manakacha Formation —— 338.0

3.0 

2.0 

2.0

15.0 

2.0

3.0

2.0 

1.0

2.5 

1.5

2.0 

2.0 

2.0

2.5 

3.0 

2.0 

2.0

15.0
MEASURED STRATIGRAPHIC SECTIONS 411

Section 7— Continued 

KAIBAB TRAIL, SOUTH-Continued

Supai Group— Continued 

Watahomigi Formation:

Claystone, pale-red, structureless; forms 

rounded ledge —————————————————

Limestone, brownish-gray, aphanitic; contains jasper lenses; weathers dusky-red ———

Sandstone, pale-red, very fine grained, very 

calcareous; weathers pale-reddish-brown; 

forms massive ledge ——————————————

Sandstone, pale-reddish-brown, very fine 

grained, resistant; weathers pale-reddishbrown; grades down into pale-reddishbrown, shaly, brittle mudstone; forms slope; 

partly concealed ————————————————

Concealed, probably pale-reddish-brown claystone ——————————————————————

Siltstone, light-reddish-brown, calcareous, 

structureless, resistant; forms rounded ledge -

Siltstone, moderate-reddish-brown; beds thick 

and irregular near top, shaly toward bottom; contains worm borings; locally shows 

scour-and-fill structure; forms slope; much 

concealed ————————————————————

Claystone, pale-reddish-brown, calcareous; 

contains thin jasper layers; contains thin 

tongues, beds and balls of light-brownishgray limestone; forms resistant ledge —————

Siltstone, moderate-reddish-brown, shaly; 

forms slope ———————————————————

Limestone, brownish-gray, aphanitic, hard; 

contains thin layers of very pale brown and 

pale-red jasper; shows weak parting plane at 

base; weathers light-brownish-gray, rough; 

forms ledge ———————————————————

Limestone, very light brownish gray, aphanitic; beds 1-3 ft thick; contains oval, 

siliceous concretions with concentric structure; weathers light-brownish-gray, pitted; 

local, thin, concretionary beds show trough 

crossbedding in channels 17 ft deep, 100 ft 

wide, with limestone pebbles in bottom; 

forms weak cliff ————————————————

Conglomerate, calcareous mudstone, and 

argillaceous limestone; unit is pale red, thinbedded (1-6 in.); forms persistent slope

Limestone, brownish-gray, aphanitic; beds 

2-4 in. thick; contains brown, oval concretions; shows weak parting plane at base;

Feet

5.0 

1.5

5.0

8.0 

7.0 

2.5

Section 7—Continued 

KAIBAB TRAIL, SOUTH-Continued

Unconformity. 

Redwall Limestone:

Limestone, gray, massive; forms sheer cliff.

Section 8

KAIBAB TRAIL, NORTH

[Slope and cliff units of Esplanade Sandstone measured on north side of 

Roaring Springs Canyon; lower part of Supai Croup measured on 

south side]

Feet

13.0

51.0

5.0 

10.0

8.5

35.0

8.0

T) C\ .LAJ.V/

Total Watahomigi Formation — 158.5 

Total Supai Group ———————— 1005.0

Hermit Shale:

Concealed slope ———————————————- ___

Contact:

Contact not visible at this locality. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope and main

cliff units:

Sandstone, grayish-orange, very fine grained, 

hard, massive, thick-bedded (4-8 ft); 

weathers to rough, gray surface; forms resistant cliff ——————————————— 21.0

Mudstone, grayish-red-brown, calcareous, 

structureless, conchoidal fracture; forms 

recess —————————————————————— 5.5

Sandstone, pale-reddish-brown, very fine 

grained, flat-bedded, thin- to mediumbedded (6-30 in.); forms receding ledges —— 11.0

Sandstone, moderate-orange-pink, very fine 

grained, calcareous, weakly cross-stratified 

on medium scale; weathers red-brown to 

black; forms cliff with sheer face ——————— 19.0

Mudstone, light-brown, calcareous, shaly; 

forms slope or bench ————————————— 11.0

Sandstone, moderate-reddish-orange, grayishorange-pink, pale-red, very fine grained 

(scattered fine grains), slightly limy; locally 

grades into gray, very thick bedded (4-30 ft) 

sandstone; structureless in lower half, crossstratified (planar type) on medium scale in 

upper part; includes mudstone partings; 

forms main cliff with sheer face and prominent bench about 30 feet below top ————— 227.5

Mudstone, grayish-red, brittle; forms slope —— 8.0

Siltstone, pale-reddish-brown, with greenish 

streaks, calcareous; weathers to black varnished face; includes a mudstone parting; 

forms sheer cliff ———————————————— 26.5
412 THE SUPAI GROUP OF GRAND CANYON

Section 8—Continued 

KAIBAB TRAIL, NORTH-Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope and 

main cliff units—Continued 

Mudstone, pale-reddish-brown, calcareous, 

weak, medium-bedded (1-2 ft); forms 

rounded base of cliff —————————————— 6.0 

Total upper cliff-slope and main 

cliff units, Esplanade SandSection 8—Continued 

KAIBAB TRAIL, NORTH—Continued

Supai Group—Continued 

Esplanade Sandstone, basal slope unit— 

Continued

Matrix: reddish-brown siltstone; coarsely 

crystalline calcite cement locally abundant.

Feet

stone -- 335.5

Esplanade Sandstone, basal slope unit: 

Mudstone, pale-reddish-brown, calcareous, 

structureless, weak; contains plant-stem 

fragments; forms recess ———————————— 5.5 

Sandstone, grayish-orange-pink, calcareous, 

weathers red-brown; forms small resistant

Mudstone, pale-reddish-brown, brittle,

crumbly; forms slope —————————————— 2.0 

Sandstone, very pale orange, altered to greenish-gray in upper part, very fine grained, 

calcareous; forms conspicuous resistant 

ledge; locally has white cast —————————— 7.5 

Sandstone, pale-reddish-brown, very fine 

grained, very silty, calcareous, locally shaly, 

elsewhere structureless; forms series of resistant ledges (2-6 ft thick) separated by thin 

slopes; total forms receding ledges —————— 25.0 

Siltstone, pale-red, calcareous, shaly; contains Rivularites sp., Walchia sp., rain pits, 

shrinkage cracks and ripple marks (cusp 

type); tongues laterally into conglomerate at 

channels; forms major slope ————————— 49.0 

Conglomerate, brown to gray, weathers 

reddish-brown; fills channels in underlying 

unit; beds dip up to 10° into channel along 

borders; topmost beds tongue into overlying 

shaly siltstone; forms weak rounded cliff —— 0-17.0 

Gravel: about 60 percent red-brown siltstone and sandstone, 40 percent pale-gray, 

dark-gray and greenish-gray limestone; 

mostly well-rounded and largely spheroidal, especially in larger grade sizes; 

limestone pebbles well-polished; elongate 

pebbles locally oriented parallel to rude 

bedding; maximum diameter at bottom 

near channel center about 5 in., common 

size near base 0.5-1 in., in upper part, 

0.25-0.5 in.

Total basal slope unit, Esplanade

Sandstone ————-—— 91.5-108.5 

Total Esplanade Sandstone - 427.0-444.0

Unconformity:

Surface of upper slope unit contains irregular 

channels filled with conglomerate and shaly 

siltstone; channel at section measured approximately 250 ft wide, 17 ft deep. 

(Units below Esplanade Sandstone measured on 

south side of Roaring Springs Canyon) 

Wescogame Formation, slope unit:

Siltstone, pale-reddish-brown, very limy; 

cross-stratified on medium scale, planar 

type; forms ledge ———————————————— 15.5 

Siltstone, gray, thin-bedded; forms thin weak 

ledges on otherwise concealed slope; total 

slope ______________________ 12 0 

Total slope unit, Wescogame

Formation — 27.5

Wescogame Formation, cliff unit:

Sandstone, moderate-orange-pink, fine- to 

very fine grained, thick-bedded (2-4 ft); 

cross-stratified on medium scale, planar 

type; weathers to black varnished surface; 

forms series of receding ledges ———————— 21.5 

Sandstone, pale-reddish-brown, fine-grained, 

very limy, massive; cross-stratified on 

medium to large scale (45 ft long), (sets 4-20 

ft thick); locally grades into limestone; forms 

major cliff ——————————————— 59.0

Mudstone, bright-reddish-brown; forms reLimestone, pale-red, aphanitic, muddy; contains thin flat beds (1-2 in. thick), weakly 

developed within massive unit; forms ledge — 

Limestone, pale-reddish-brown, aphanitic, 

concretionary; locally contains mudstone; 

weathers to rounded surface; forms recess — 

Sandstone, very pale orange, fine-grained, 

calcareous, sugary, massive; weathers to 

dark-gray; forms resistant ledge ———————_ 

Total cliff unit, Wescogame

Formation ——————————— 99.0 

Total Wescogame Formation —— 126.5

1.0

8.0

3.5

6.0
MEASURED STRATIGRAPHIC SECTIONS 413

Section 8—Continued 

KAIBAB TRAIL, NORTH-Continued

Supai Group—Continued

Manakacha Formation, slope unit:

Sandstone, pale-reddish-brown, calcareous, 

very fine grained; includes much fine sand; 

shaly; forms slope or bench, locally contains 

weakly developed ledge near middle —————

Sandstone, moderate-orange-pink, finegrained, calcareous, sugary; cross-stratified 

on large scale; forms massive cliff with sheer 

face ———————————------——————————

Mudstone, pale-red, slightly calcareous, brittle; 

forms recess ———————————————

Limestone, moderate-orange-pink, very fine 

grained, massive, medium-bedded (2 ft); 

forms weak rounded ledge ————————

Siltstone, pale-red, slightly calcareous; shaly 

at base, thin-bedded (6-24 in.) above; forms 

prominent bench —————————

Total slope unit, Manakacha 

Formation —————————

Manakacha Formation, cliff unit:

Sandstone, moderate-orange-pink, finegrained, friable, medium- to thick-bedded 

(1-5 ft); cross-stratified on medium scale, 

low-angle planar type; forms cliff with 

straight face ———————————————

Mudstone, pale-reddish-brown, calcareous; 

contains much concretionary limestone; 

forms recess ———————————————

Siltstone, pale-reddish-brown, calcareous, 

medium- to thick-bedded (2.5-10 ft); weakly 

cross-stratified on medium scale in upper 

part; zone of warping (differential loading) 

near base; forms series of cliffs with thin 

recesses of bright-red mudstone between —— 

Surface of contorted beds.

Sandstone, moderate-orange-pink, calcareous, 

very fine grained, massive, very resistant, 

thick-bedded (2-6 ft); weakly cross-stratified; forms ledge —————————————

Total cliff unit, Manakacha

Formation ————————• 

Total Manakacha Formation 

Watahomigi Formation, upper slope unit:

Limestone, dark-gray, granular; contains 

patches and lenses of red-brown mudstone; 

forms recess —————————————————

Limestone, pale-reddish-brown, aphanitic, 

medium-bedded (2-3 ft); contains very thin 

siliceous layers; weathers to brown rounded 

surface; forms ledge ———————————

Feet

39.0

25.5 

2.0

1.5

- 12.5 

80.5

21.5

2.5

Section 8 — Continued 

KAIBAB TRAIL, NORTH-Continued

Supai Group — Continued 

Watahomigi Formation, upper slope unit —

Continued

Limestone, medium-gray, aphanitic, granular; 

contains patches and lenses of moderatereddish-brown mudstone; locally fills erosion channels extending several feet into 

underlying unit; forms recess — ——— — ———

Limestone, pale-reddish-brown, includes 

much very fine grained sand; mediumbedded (2-3 ft); weakly cross-laminated on 

medium scale, wedge-planar type; contains 

fusulinids (Pseudostaffella sp.); weathers to 

straight, varnished face with silt etched on 

surface; forms ledge —— —— ——— ——— ——

Limestone, pale-reddish-brown, and mediumgray, very fine grained, very muddy; forms 

resistant, rounded ledges — ——— ——— ———

Siltstone, pale-reddish-brown, limy; bedding 

flat, weakly developed; weathers to straight 

face; forms ledge —————————————

Mudstone, bright-reddish-brown, shaly; contains some concretionary red-brown siltstone; forms recess ————————————

Limestone, light-brownish-gray, aphanitic; 

contains thin jasper layers and lenses; forms

Feet

102.0

24.5

— 150.5

— 231.0

2.0

6.0

Siltstone, reddish-brown, shaly; forms recess —

Limestone, pale-reddish-brown, aphanitic; 

contains thin jasper layers and lenses; forms 

two irregular but resistant ledges with lenses 

of red mudstone in middle ———— — — ———

Siltstone, pale-reddish-brown, calcareous, 

flat-bedded; weathers to straight, black varnished face; forms base of cliff — — —— ——

Siltstone, pale-reddish-brown, friable, structureless; contains thin beds of crumbly, 

bright-red mudstone at top and bottom; 

rorms recess ——————————————————————

Sandstone, pale-gray, very fine grained; crossstratified, planar type; weathers to black 

varnished face; forms ledge ——— — —— ———

Concealed slope, probably contains friable, 

pale-reddish-brown, calcareous siltstone ——

Siltstone, pale-red, calcareous, shaly; contains 

layers of limestone concretions; grades upward into dark-gray, jasper-bearing limestone; forms weak ledge —— ——— —— — ——

Conglomerate, grayish-red; weathers to grayish-red-purple ledge; forms bed of irregular 

thickness, filling small channels ——————— 2

2.0

7.5

4.0

7.5

2.0

4.0 

0.5

7.0 

19.0

5.5

2.5 

8.0

4.0 

0-3.0
414 THE SUPAI GROUP OF GRAND CANYON

Section 8—Continued 

KAIBAB TRAIL, NORTH-Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit— 

Continued

Conglomerate—Continued 

Gravel, composed largely of red jasper pebbles, but also contains black to gray flint, 

white and yellow chert, red siltstone, 

light-gray limestone; mostly subangular to 

subrounded, small clasts well-rounded; 

maximum diameter 6 in., common range 

0.25-0.75 in.

Matrix: dark-red-brown, calcareous mudstone.

Total upper slope unit, Watahomigi Formation ———————

Watahomigi Formation, middle cliff and lower 

slope units: 

Concealed slope ——————————————

Limestone, light-brownish-gray, aphanitic; 

contains siliceous bands; forms massive

lori of* _._.———____,._______________ icuge

Siltstone, pale-reddish-brown, shaly, and palereddish-brown, very fine to fine-grained, 

shaly sandstone; forms slope, largely conLimestone, dolomitic, medium-light-gray, 

aphanitic, massive; contains thin layers of 

jasper; forms ledge ———————————

Feet

7.5

84.5

4.0

3.0

8.0

4.0

Section 8—Continued 

KAIBAB TRAIL, NORTH-Continued

Supai Group—Continued 

Watahomigi Formation, middle cliff and lower 

slope units—Continued

Mudstone, grayish-reddish-purple, noncalcareous, hard, brittle, crumbly; forms slope 

Total middle cliff and lower 

slope units, Watahomigi Formation ————————————— 64.5 

Total Watahomigi Formation — 149.0 

Total Supai Group ———————— 950.5

Unconformity:

Unconformity inferred—surface even and flat

where observed in area. 

Redwall Limestone: 

Horseshoe Mesa Member: 

Limestone, olive-gray, aphanitic; contains 

much red-brown mudstone filling solution 

cavities; forms top of main cliff ——— Not measured

Section 9 

HERMIT TRAIL

[Measurement begins south of major slump area crossing trail on east 

side of canyon]

Feet

Limestone, dark-gray, fine-grained; contains 

jasper; forms series of thin (2-3 in.) ledges; 

alternates with pale-reddish-brown, calcareous, shaly, silty mudstone; forms slope ——— 5.5

Limestone, grayish-red-purple, aphanitic, massive thick-bedded (3 ft); contains thin irregular siliceous bands; weathers to purplish surface; forms ledge ———————————————— 3.0

Concealed slope ————————————————— 22.0

Siltstone, grayish-red, muddy, thin-bedded

(0.5-2 ft); forms weak ledges ————————— 5.0

Conglomerate, moderate- to dark-reddishbrown; locally distributed as pockets in 

basal mudstone ———————————————— 0.0-2.5 

Gravel: composed locally of white quartz, 

elsewhere of chert and flint; angular to 

subrounded; maximum diameter 1 in.; 

common range 0.25-0.5 in. 

Matrix: dark-reddish-brown mudstone; 

clasts loosely packed.

Hermit Shale. 

Unconformity:

Channels with sloping sides cut as much as 

55 ft deep into massive beds of Supai and 

filled with shaly siltstone of Hermit Shale. 

Supai Group:

Esplanade Sandstone, upper cliff-slope and main 

cliff units:

Siltstone, grayish-orange-pink, sandy (very

fine grained, some fine-grained), massive,

cross-stratified on large scale; forms cliff ——

Siltstone, moderate-orange-pink, sandy, shaly;

forms bench —————————————————

Sandstone, very pale gray to moderate-orangepink, very fine grained (subrounded, sphericity good), silty (32 percent), thick-bedded 

(6-8 ft); contains thin shaly parting; forms

Sandstone, moderate-reddish-brown, very 

fine grained (scattered fine grains), structureless; includes thin ledge of grayishorange-pink siltstone, muddy, near middle; 

total forms prominent bench ————————

19.0

3.0

33.0

29.0
MEASURED STRATIGRAPHIC SECTIONS 415

Section 9—Continued 

HERMIT TRAIL-Continued

Feet

Supai Group—Continued

Esplanade Sandstone, upper cliff-slope and main 

cliff units—Continued

Sandstone, moderate-orange-pink, very fine 

grained, silty, thick-bedded (3-4 ft), crossstratified on small scale; forms resistant

lcO^6 ———————————--———————•*—————————————————————————————— JL JL, O

Siltstone, pale-reddish-brown, sandy, gnarlybedded, friable; forms bench ————————— 3.0

Sandstone, moderate-orange-pink, very fine 

grained (subrounded, sphericity fair), limy 

(30 percent), cross-stratified on large scale; 

grades downward into pale-reddish-brown, 

very fine grained sandstone; grains subrounded, sphericity good; iron-oxide coatings; comprised of several beds, thicker 

toward top; total forms prominent red to 

black cliff ________________________ 49.5

Mudstone, moderate-reddish-brown, sandy 

(subrounded grains), structureless; weathers 

shaly; forms slope with rounded ledges ——— 9.0

Sandstone, moderate-reddish-brown to grayish-orange-pink, poorly sorted, very fine 

grained (51 percent), much medium- and 

fine-grained (subangular to subrounded), 

sphericity fair, calcareous (35 percent), very 

hard; contains low-angle cross-stratification 

on medium scale near bottom, large-scale 

near top; four massive units (8-20 ft thick) 

with thin (6-24 in.) parting zones of shaly 

siltstone; forms major cliff ————————

Sandstone, dark-reddish-brown, very fine 

grained, silty, cross-stratified; contains limy 

concretionary balls 0.5-3 in. in diameter ——

Sandstone, grayish-red, very limy, very fine 

grained, fossiliferous, cross-stratified on 

medium scale; forms resistant, black cliff ——

Concealed slope ——————————————

Sandstone, moderate-reddish-brown, very 

fine grained, (subrounded, sphericity fair), 

calcareous, friable, cross-stratified on large 

scale; forms double ledge ———————— 

Total upper cliff-slope and main 

cliff units, Esplanade Sandstone ——————————————— 247.5

Section 9—Continued 

HERMIT TRAIL-Continued

Feet

57.0

6.0

10.0

5.5

12.0

Esplanade Sandstone, basal slope unit:

Siltstone, bright-red, shaly; forms slope, partly 

concealed ———————————————————— 11.0

Supai Group—Continued 

Esplanade Sandstone, basal slope unit— 

Continued

Sandstone, moderate-reddish-brown to moderate-orange-pink, very fine grained (subrounded), calcareous (30 percent), sphericity 

fair, silty, massive, structureless; forms 

prominent rounded cliff ——————————— 14.5 

Siltstone, moderate-reddish-brown, muddy, 

iron-oxide-coated grains, calcareous, flatbedded, thin-bedded, (0.5-1 ft); forms base 

of cliff ————————————_______ 2.0

Mudstone, moderate-reddish-brown; silty; 

iron-oxide-coated grains, very calcareous, 

contains pale-yellowish-gray limy concretions, 0.5-4 in. in diameter; forms recess —— 7.0 

Siltstone, red-brown, thick-bedded (2-3 ft);

forms rounded ledges ————————————— 6.0 

Concealed slope ————————————————— 5.5 

Sandstone, moderate-reddish-orange, very 

fine grained, resistant; contains elongate 

nodules of limestone, 0.5-1 in. thick, 5-15 

in. long; forms resistant ledge ———————— 8.5 

Siltstone, moderate-reddish-brown, muddy, 

calcareous, iron-oxide-coated grains, shaly; 

contains one bed of resistant bright-red 

siltstone; forms slope —————————————— 9.0 

Limestone, pale-red, very fine grained, concretionary; with red-brown structureless 

mudstone; forms slope ———————————— 4.5 

Concealed slope ————————————————— 4.5 

Mudstone, moderate-reddish-brown, shaly;

contains shrinkage cracks; forms slope ——— 2.0 

Conglomerate, red-brown and gray, resistant, 

medium-bedded (0.5-2 ft); well-stratified, 

locally with sand laminae, elsewhere gravel 

layers; locally cross-stratified on small scale; 

weathers gray; forms ledge —————————— 5.0 

Matrix: pale- to moderate-reddish-brown,

siltstone and sandstone. 

Pebbles: moderate-reddish-brown, siltstone, 

olive-gray and medium-gray limestone, 

moderate-reddish-brown mudstone; mostly well-rounded, some subangular; diameter 0.25-0.5 in. in most layers, locally as 

much as 3 in. ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 79.5 

Total Esplanade Sandstone ——— 327.0
416 THE SUPAI GROUP OF GRAND CANYON

Section 9—Continued 

HERMIT TRAIL—Continued

Supai Group—Continued

Wescogame Formation, slope unit:

Claystone, light-green and red, structureless; 

forms recess ——————————————

Sandstone, very pale orange to pale-orangepink, very fine grained (grains subrounded, 

sphericity fair), silty, calcareous, thickbedded (3-6 ft) in middle, medium-bedded 

(1-3 ft) at top and bottom; weakly crossstratified on large scale; forms cliff ——————

Siltstone, moderate-reddish-brown, muddy, 

brittle, structureless; forms slope —————

Limestone, pale-red, very fine grained, muddy 

(insoluble, 30 percent); contains limestone 

concretions 1-2 in. in diameter; forms 

rounded ledge —————————————

Siltstone, dark-reddish-brown, very limy (42 

percent), very hard; weathers to resistant 

ledge ——————————————————

Mudstone, moderate-reddish-brown, shaly to 

thin-bedded (0.5-1 in.); forms slope ———

Sandstone, moderate-orange-pink, fine- to 

very fine grained, silty, calcareous; includes 

two thick (3-5 ft) beds; weathers to rounded 

black surface; forms resistant ledge ————

Siltstone, moderate-reddish-brown to palered, muddy, very calcareous, thin-bedded 

(0.5-2 in.); contains one medium-bedded 

(1-2 ft) ledge near center; forms slope ————_ 

Total slope unit, Wescogame 

Formation —————————

Feet

1.0

Feet

29.5

7.0

3.0

2.0

10.0

7.0

32.5

92.0

Wescogame Formation, cliff unit:

Sandstone, moderate-orange-pink, very fine 

grained, subrounded, sphericity good, silty, 

thin-bedded (0.5-2 in.); grades upward to 

pale-reddish-brown, medium-bedded siltstone; weathers white; forms conspicuous 

weak ledge ——————————————————— 3.0 

Sandstone, very pale orange, fine-grained 

(scattered very fine grains), (grains subrounded, sphericity good), weakly crossstratified on large scale; forms resistant gray

Claystone, dark-reddish-brown, silty and very 

light grayish-green limestone, silty, structureless; brittle, crumbly; forms recess ———— 3.0

Mudstone, pale-red, very silty, shaly to thinbedded (2-12 in.), calcareous; contains a few 

limestone concretions; forms weak ledges — 3.0

9.0

20.5

2.0

80.5

Section 9—Continued 

HERMIT TRAIL-Continued

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued

Siltstone, moderate-reddish-brown with palegray spots, muddy, sandy (grains subrounded to rounded); forms slope, partly 

concealed —————————————————

Sandstone, pale-orange-pink, fine- to very 

fine grained (grains subrounded, sphericity 

fair), medium-bedded (0.5-3 ft), weakly 

cross-stratified on medium scale; weathers 

gray; forms resistant ledge ————————

Sandstone, pale-reddish-brown, very fine 

grained, (grains subrounded, sphericity 

fair), friable; forms slope or weak, rounded

Sandstone, pale-grayish-orange with very pale 

greenish gray, fine-grained (47 percent) to 

very fine grained (32 percent); grains subrounded, sphericity good, very thick bedded 

(2-15 ft), cross-stratified on medium to large 

scale; weathers red to brown; forms major 

clif f——————————————————

Mudstone, dark-reddish-brown, calcareous, 

very silty, hard, thick-bedded (6-20 ft); contains elongate, unoriented nodules of gray 

limestone (1 in. thick by 6-20 in. long); 

forms lower part of main cliff ———————

Mudstone, reddish-brown, structureless, 

crumbly; forms recess ——————————

Unconformity:

Erosion surface; irregular surface with channels 2-3 ft deep in limestone filled with 

reddish-brown mudstone; locally contains 

pebbles at surface. ____ 

Total cliff unit, Wescogame

Formation ——————————— 148.5 

Total Wescogame Formation —— 240.5

Manakacha Formation, slope unit:

Limestone, pale-reddish-gray, very fine 

grained, silty (25 percent); contains pockets 

of mudstone; forms rounded ledge —————

Siltstone, moderate-reddish-brown, muddy, 

contains gray limestone concretions 0.5-1 

in. in diameter; forms weak, rounded ledge —

Siltstone, moderate-reddish-brown, thickbedded (2-5 ft), massive, friable; forms 

weak, rounded ledges; alternating with 

moderate-reddish-brown, limy (42 percent), 

shaly mudstone; forms slopes; total bed ——

14.0

0.5

2.0

3.0

49.5
MEASURED STRATIGRAPHIC SECTIONS 417

Section 9—Continued 

HERMIT TRAIL—Continued

Supai Group—Continued 

Manakacha Formation, slope unit—Continued

Sandstone, grayish-orange-pink, medium- to 

fine-grained (grains subangular to subrounded, sphericity fair), friable, crossstratified on large scale; forms prominent 

white cliff ————————————————————

Dolostone, moderate-reddish-brown, silty 

(muscovite-rich), thin-bedded (2-24 in.); 

locally weathers shaly; forms series of weak

Feet

14.0

Total slope unit, Manakacha

Formation ——————————— 89.5

Manakacha Formation, cliff unit:

Siltstone, light-brownish-gray to light-olivegray, very limy, dolomitic (44 percent), 

thick-bedded (6-20 ft); cross-stratified on 

medium scale, massive, silty (sandy); 

weathers black to red; forms cliff ——————— 53.5

Siltstone, pale-red, very fine grained, very 

limy (46 percent calcitic dolomite), thinbedded (2-12 in.); forms slope, partly concealed ——————————————————————— 23.0

Sandstone, very pale orange, very fine grained, 

(grains subrounded, sphericity fair), (scattered fine and medium grains), thickbedded, friable, massive; forms cliff ————— 13.5

Sandstone, moderate-reddish-orange, very fine 

grained, limy (33 percent), very silty, crossstratified on medium scale; forms weak ledge 18.5

Sandstone, moderate-reddish-brown, very fine 

grained (grains subrounded), sphericity 

good, structureless, friable; forms slope, 

much concealed ———————————————— 16.0

Sandstone, moderate-orange-pink, very fine 

grained, subrounded, sphericity good, 

medium-bedded (2-4 ft), limy, structureless; 

forms rounded ledges ————————————— 6.5

Concealed slope ————————————————— 5.0

Sandstone, grayish-orange-pink, very fine 

grained (grains subrounded, sphericity fair), 

friable, cross-stratified on large scale; weathers pink; forms cliff ——————————————— 13.0

Limestone, pale-red, fine-grained, silty (44 percent); contains fusulinids (Fusulinella sp.); 

cross-stratified on medium scale; forms cliff ~ 7.0

Mudstone, moderate-reddish-brown, structureless, crumbly; forms slope, partly conSection 9—Continued 

HERMIT TRAIL-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Limestone, pale-red, dolomitic, silty, very 

fine grained, medium-bedded (2-3 ft); forms 

receding ledges —————————————————

Limestone, dolomitic, pale-red, very fine 

grained, silty (40 percent), concretionary, 

forms rounded ledge ——————————————

Siltstone, very pale orange gray to palereddish-brown, calcareous, thin-bedded (2-6 

in.); includes 1-ft-thick ledge of pale-reddishbrown siltstone with limy lenses; forms 

slope, partly concealed ————————————

Sandstone, moderate-reddish-orange, very fine 

grained, muddy, calcareous, thick-bedded 

(3-6 ft); cross-stratified on small scale; forms 

resistant cliff ——————————————————

Mudstone, deep-reddish-brown, structureless; 

forms slope ———————————————————

Limestone, light-grayish-red, fine-grained, 

silty (40 percent); contains jasper near top; 

forms ledge ———————————————————

Sandstone, moderate-reddish-brown to paleorange-pink, very fine grained (scattered 

fine grains), calcareous, structureless; forms 

slope ——————————————————————

Limestone, very light brownish gray, very 

fine grained, silty (40 percent), thick-bedded 

(2-4 ft); forms cliff ————————————

Limestone, olive-gray and dark-greenish-gray, 

very fine grained, thick-bedded, insoluble 

(40 percent); contains jasper lenses; forms

Feet

7.0

2.5

8.0

18.5 

3.0

4.0

2.0 

11.0

-— 6.0

Mudstone, dark-reddish-brown, very silty, 

very thick bedded (4-10 ft), massive; forms

Total cliff unit, Manakacha

Formation ——————————— 255.5 

Total Manakacha Formation —— 345.0 

Watahomigi Formation:

Siltstone, moderate-reddish-brown, muddy,

structureless; forms rounded ledge ————— 2.5 

Limestone, reddish-gray, very fine grained, 

silty (insoluble, 42 percent); contains jasper 

lenses near top; forms ledge —————————— 6.0 

Limestone, gray to purple, nodular; matrix

shaly, red-brown mudstone; forms recess — 2.0 

Mudstone, moderate-reddish-orange, very 

silty, calcareous, thick-bedded (2-4 ft); 

weathers shaly; forms ledge —————————— 8.0
418 THE SUPAI GROUP OF GRAND CANYON

Section 9—Continued 

HERMIT TRAIL—Continued

Feet

Supai Group—Continued 

Watahomigi Formation—Continued

Siltstone, reddish-brown, structureless; forms

Limestone, pale-red with light-olive-gray, finegrained, very silty, medium-bedded; 

weathers black; forms ledge ————————— 7.5

Limestone, gray to purple, aphanitic; contains 

jasper bands; forms ledge ——————————— 1.5

Limestone, gray, concretionary; forms weak

Concealed slope ————————————————— 2.0

Mudstone, dark-reddish-brown, silty; contains gray limestone concretions; forms 

ledge ——————————————————————— 2.0

Limestone, dark-reddish-brown to moderatereddish-brown, muddy (25 percent), 

medium-bedded, crumbly; forms slope, 

largely concealed ———————————————— 20.0

Siltstone, pale-red-purple, calcareous (30 percent), locally very shaly; forms cliff ————— 11.0

Siltstone, moderate-reddish-brown and grayish-red, muddy, shaly; forms slope —————— 8.5

Limestone, grayish-red, very fine grained, 

silty, wavy bedded; locally concretionary; 

forms rounded ledge —————————————— 3.0

Siltstone, reddish-brown, shaly; forms slope — 2.0

Limestone, moderate-reddish-brown, silty (30 

percent), thick-bedded (2-4 ft); weathers 

black; forms ledge ——————————————— 13.0

Mudstone, reddish-orange, and grayish-redpurple, shaly, muddy, limy siltstone; forms 

long slope ———————————————————— 39.5

Limestone, brownish-gray, fine-grained, silty, 

thick-bedded; contains irregular jasper bed 

at top; forms ledge ——————————————— 4.5

Limestone, grayish-red, very fine grained, 

very muddy, concretionary; contains red 

mudstone matrix; forms weak ledge ————— 3.0

Mudstone, grayish-red, brittle; forms slope —— 4.5

Limestone, light-brownish-gray with pale-red, 

very fine grained (insoluble, 30 percent), 

concretionary to massive; contains jasper; 

forms ledge ——————————————————— 3.0

Limestone, gray, concretionary; contains red

mudstone matrix; forms slope ———————— 3.5

Limestone, light-brownish-gray with lightolive-gray spots, very fine grained; contains 

many jasper bands, 1-3 in. thick; forms

Section 9—Continued 

HERMIT TRAIL-Continued

Supai Group—Continued 

Watahomigi Formation—Continued

Limestone, dark-gray to purple; muddy (40 

percent); concretionary, with matrix of red, 

crumbly mudstone; forms weak ledge - 

Mudstone, deep-red, silty, weakly bedded, 

brittle; contains 

subangular pebbles

Feet

3.5

many 

(1-6 in.

rounded to 

diameter) of

underlying Redwall Limestone near base; 

Total Watahomigi Formation —

44.0

Total Supai Group —

— 206.5

- 1,119.0

Unconformity:

Erosion surface; shows channels with relief of 

12-17 ft in horizontal distance of 50 ft; sink 

topography. 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, gray, aphanitic, thin-bedded forms 

receding ledges ———————————— Not measured

Section 10 

BASS TRAIL

[On west side of Bass Canyon east of Mount Huethawali]

Feet

93.5

Hermit Shale:

Mudstone, moderate-reddish-brown, shaly;

forms slope ———————————————————___

Contact:

Not described. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope and main

cliff units:

Sandstone, very pale orange, very fine grained, 

moderately resistant; forms ledge —————— 3.5

Sandstone, moderate-reddish-orange, very fine 

grained, shaly; includes two small (1-2 ft 

thick) ledges of weak, structureless siltstone; 

total forms slope ———————————————— 21.0

Sandstone, moderate-reddish-orange, very 

fine grained, moderately friable, weakly 

cross-stratified; forms resistant, rounded 

ledge ——————————————————————— 5.5

Siltstone, moderate-reddish-orange, friable; 

forms bench —————————————————— 2.0
MEASURED STRATIGRAPHIC SECTIONS 419

Section 10—Continued 

BASS TRAIL—Continued

Supai Group—Continued

Esplanade Sandstone, upper cliff-slope and main 

cliff units—Continued 

Sandstone, light-red-brown, very fine grained;

Mudstone, dark-red-brown, shaly; forms

Sandstone, moderate-reddish-brown, very 

fine grained, medium-bedded (1-2 ft); forms 

resistant ledge —————————————

Siltstone, moderate-reddish-orange, shaly; 

forms bench ———————————————

Sandstone, moderate-reddish-brown, very fine 

grained, medium-bedded (1-2 ft); forms cliff -

Siltstone, moderate-reddish-orange, sandy, 

friable, medium-bedded (1-3 ft); forms wide 

bench ——————————————————

Sandstone, moderate-reddish-orange, fine- to 

very fine grained, thick-bedded (3-4 ft); 

weathers to black varnished surface; forms 

cliff_______________________

Mudstone, dark-red-brown, silty, mediumbedded (1-3 ft); forms slope ———————

Sandstone, moderate-reddish-brown, very fine 

grained, thick-bedded (3-4 ft); weathers to 

black varnished surface; forms cliff or series 

of resistant ledges ————————————

Siltstone, moderate-reddish-orange, silty, 

medium-bedded (1-3 ft); forms irregular 

ledges or slope ————————————

Sandstone, moderate-reddish-brown to white, 

very fine grained, very thick bedded (2-30 

ft); large-scale compound cross-strata etched 

out on surface; weathers with black varnish; 

forms cliff with straight face ————————

Sandstone, moderate-reddish-orange, very fine 

grained, silty, medium-bedded (1-3 ft); 

forms irregular ledges or slope ———————

Sandstone, pale-red to grayish-orange-pink, 

very fine grained to silty, hard, very thick 

bedded (2-30 ft); weakly tabular-planar to 

wedge-planar cross-stratification on medium 

to large scale (10-40 ft); weathers to 

rounded, black varnished surface; forms 

straight cliff ——————————————•

Section 10—Continued 

BASS TRAIL—Continued

Feet Feet

7.5 

5.5

7.0

12.0

13.0

8.0

19.0

5.5

8.0 

11.0

13.5

14.5

— 111.0

Mudstone, deep-red-brown; forms "parting" — 1.0

Supai Group—Continued

Esplanade Sandstone, upper cliff-slope and main 

cliff units—Continued

Sandstone, very pale red, very fine grained, 

medium- to thick-bedded (2-4 ft); planar 

cross-stratified on medium to large scale 

(10-30 ft); weathers to black varnished surface; forms weak, rounded cliff ——————— 34.0 

Total upper cliff slope and main 

cliff units, Esplanade Sandstone —————————————— 302.5

Esplanade Sandstone, basal slope unit:

Sandstone, pale-reddish-brown, very fine 

grained, silty, flat-bedded, thin- to mediumbedded (1-24 in.); moderately resistant; surface weathers shaly, locally micaceous; 

forms base of main cliff, locally forms slope — 14.5

Siltstone, moderate-reddish-orange, calcareous, shaly; forms slope at base of cliff ———— 12.0

Sandstone, bright-red-brown, very fine 

grained, friable, cross-stratified on medium 

scale; forms cliff ———————————————— 18.5

Siltstone, pale-red, noncalcareous, friable, 

structureless; forms ledges 2-3 ft thick with 

slopes of deep-red-brown, brittle mudstone

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, friable, cross-stratified 

on medium scale; forms ledge ———————— 9.0 

Concealed slope ————————————————— 14.0 

Siltstone, pale-red, limy, flat-bedded, thinbedded (4-12 in.); weathers to blocks; forms 

receding ledges or slope ———————————— 3.5 

Conglomerate, brownish-gray; fills erosion 

channels in underlying siltstone; forms weak 

ledge or slope ————————————————— 15.0 

Pebbles: brownish-gray, pale-gray, and 

dark-gray limestone; subrounded to 

rounded; largely spheroidal, but some 

elongate and tabular; elongate pebbles 

oriented parallel to weakly developed bedding; average diameter 0.25-0.75 in., 

maximum 2 in.

Matrix: red-brown, limy siltstone. ____ 

Total basal slope unit, Esplanade Sandstone ———————— 114.0 

Total Esplanade Sandstone ——— 416.5
420 THE SUPAI GROUP OF GRAND CANYON

Section 10—Continued 

BASS TRAIL—Continued

Supai Group—Continued 

Unconformity:

Channel 240 ft wide and 15 ft deep where 

observed, cut into shaly siltstone and filled 

with limestone pebble conglomerate. 

Wescogame Formation, slope unit:

Siltstone, pale-reddish-brown, shaly; some 

very fine sand; forms slope ————————

Sandstone, moderate-orange-pink, very fine 

grained (scattered rounded, fine grains), calcareous, friable, cross-stratified on medium 

scale, planar type; forms bench and 2-ft 

thick ledge ————————————————

Total slope unit, Wescogame 

Formation —————————

Wescogame Formation, cliff unit:

Sandstone, white, fine- to very fine grained, 

cross-stratified on large scale; forms cliff —— 

Sandstone, moderate-orange-pink, very fine 

grained, calcareous, friable, platy to thinbedded; forms slopes or recesses —————— 

Sandstone, moderate-orange-pink, very fine 

grained, includes many fine grains, crossstratified on large scale; forms cliff with

Sandstone, pale-reddish-brown, very fine 

grained, noncalcareous, muddy, friable, 

structureless; forms recess under cliff ————

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, structureless, hard; 

forms ledge ————————————————

Sandstone, moderate-orange-pink, very fine 

grained, includes many fine grains, friable, 

calcareous, medium-bedded (2-4 ft); crossstratified on small to medium scale; forms 

cliff or series of receding ledges ———————

Sandstone, moderate-orange-pink, very fine 

grained, slightly calcareous, cross-stratified 

on large scale; forms cliff ———————————_ 

Total cliff unit, Wescogame 

Formation ———————————_ 

Total Wescogame Formation —— 

Manakacha Formation, slope unit:

Siltstone, pale-reddish-brown; includes very 

fine sand grains; shaly to thin-bedded; forms 

slope or weak ledge ————————————

Concealed slope ——————————————

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, flat-bedded; forms 

resistant cap to underlying cliff ———————

Feet

18.0

5.0

23.0

16.5

10.0

24.0

3.0

4.5

49.5

33.0

140.5

163.5

3.0 

14.5

2.0

Section 10—Continued 

BASS TRAIL—Continued

Supai Group—Continued 

Manakacha Formation, slope unit—Continued 

Sandstone, moderate-orange-pink, fine- to 

very fine grained; includes much silt-size 

quartz; slightly calcareous, friable, crossstratified on large scale (planes 50+ ft long); 

forms cliff with sheer face —————————

Mudstone, grayish-red, noncalcareous, brittle, 

crumbly; forms slope ———————————

Sandstone, pale-red, silty, calcareous, platy to 

thin-bedded (0.5-6 in.); contains plant impressions; forms slope and weak ledges ——— 

Total

Feet

42.0

5.5

17.5

slope unit, Manakacha 

Formation ——————————— 84.5

Manakacha Formation, cliff unit:

Sandstone, moderate-orange-pink, very fine 

grained (includes many fine grains), calcareous, friable, flat-bedded, medium-bedded 

(2-4 ft); forms rounded ledges ———————— 8.0

Sandstone, moderate-orange-pink, very fine 

grained, calcareous, friable, cross-stratified 

on large scale (wedge-planar type); forms 

rounded, resistant cliff ———————————— 19.0

Concealed slope ————————————————— 10.0

Sandstone, grayish-orange-pink, very fine 

grained, some fine grains, calcareous, flatbedded, medium-bedded (1-2 ft); forms 

bench or weak cliff —————————————— 5.5

Limestone, pinkish-gray, very sandy, grades 

upward into very fine grained, moderatereddish-orange sandstone, with some fine 

sand; hard, cross-stratified on medium to 

large scale, planar type; units medium to 

thick (2-10 ft); weathers to black varnished 

face; forms resistant cliff ——————————— 57.0

Limestone, medium-gray, very silty, structureless or contains wavy laminae (probably 

algal); weathers black; forms resistant ledge 

at base of cliff ————————————— 3.0

Sandstone, pale-red, very calcareous, silty; 

contains scattered limestone nodules; also 

contains chert in upper part; forms slope or 

rounded ledges ———————————————— 22.0

Limestone, pale-red; contains very fine grained 

quartz, and rounded carbonate grains scattered throughout; sandy, prominently crossstratified on medium scale; forms resistant
MEASURED STRATIGRAPHIC SECTIONS 421

Section 10—Continued 

BASS TRAIL—Continued

Feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Siltstone, pale-red, limy, shaly to thin-bedded 

(1-4 in.); contains limestone concretions 1-2 

in. in diameter parallel to beds; forms slope 

or weak ledge ————————————————— 10.0

Siltstone, pale-reddish-brown, calcareous; 

forms weak, rounded ledge —————————— 1.0

Sandstone, grayish-pink, very fine grained, 

very silty; grades upward into medium-lightgray, hard, weakly-laminated and crosslaminated limestone; contains dark limestone nodules (probably algal) in upper part; 

forms resistant receding ledges ———————— 7.0

Sandstone, moderate-orange-pink, finegrained, calcareous, weakly cross-stratified 

on medium scale; contains abundant jasper 

lenses and bands; weathers gray; grades upward into silty gray aphanitic limestone; 

forms massive cliff ——————————————— 21.0

Mudstone, deep-red-brown; forms recess ——— 1.0

Sandstone, moderate-orange-pink, very fine

grained, friable, cross-stratified on medium

scale, units 3-5 ft thick; contains scattered

white grains; forms resistant cliff ——————— 9.0

Total cliff unit, Manakacha

Formation ——————————— 179.0 

Total Manakacha Formation —— 263.5

Watahomigi Formation:

Sandstone, pale-red, very fine grained, calcareous, thin- to medium-bedded; contains plant 

stems (Walchia?) and worm trails; weathers 

blocky; forms recess under cliff ——————— 5.0

Concealed slope, with deep-red-brown mudstone at top ——————————————————— 6.5

Siltstone, pale-red, slightly calcareous, shaly; 

forms slope with weak, 2-ft-thick ledge in

Sandstone, pale-reddish-brown with white 

specks throughout, fine- to very fine grained, 

calcareous, cross-stratified on medium scale, 

planar type; weathers to rounded surface; 

forms ledge ——————————————————— 4.5

Sandstone, moderate-reddish-orange, very fine 

grained, slightly calcareous, friable, structureless, hard; forms resistant ledge ————— 4.0

Section 10 — Continued 

BASS TRAIL— Continued

Supai Group — Continued 

Watahomigi Formation — Continued

Siltstone, pale-red, limy, thin-bedded (1-4 in.); 

contains limestone concretions 1-2 in. in 

diameter parallel to beds; forms slope or 

weak ledge ———————————————————

Concealed slope —————————————————

Limestone, pale-red, very silty; contains small 

amount of jasper; forms resistant ledge ———

Concealed slope —————————————————

Sandstone, grayish-orange-pink, very fine 

grained, limy, medium- to thick-bedded 

(1.5-4 ft); weathers to black varnished surface; underlain by variable thicknesses of 

fissile, pale-red, noncalcareous siltstone that 

forms recesses; bottom contact irregular; 

forms resistant ledge ——————————————

Siltstone, pale-red, calcareous, fissile; contains 

abundant gray limy concretions, 0.5-2 in. in 

longest dimension (mostly flattened ovoids); 

forms slope or recess

Siltstone, pale-reddish-brown, calcareous, 

structureless, crumbly; forms slope —————

Concealed slope —————————————————

Limestone, gray, aphanitic; contains bands of 

white chert and jasper; forms ledge —————

Siltstone, pale-red, very limy, crumbly; forms

Feet

11.0

15.0

3.0 

5.5

11.0

6 . 0

3.0 

6.5

2.5

£i.\j / li 

6.0

Limestone, grayish-red, aphanitic; contains 

very irregular masses of chert; weathers to 

silty, needlelike surface; forms weak ledge —

Limestone, pale-red with very light gray 

blotches, aphanitic; contains abundant thin 

(0.25-2 in.) bands of chert, both parallel to 

bedding and crosscutting at low angles; chert 

weathers to white conspicuous surface; 

forms ledge ——————————————————— 8.0

Concealed slope, with crumbly, pale-red, calcareous claystone near top —————————— 14.5 

Total Watahomigi Formation — 125.0 

Total Supai Group ———————— 968.5

Unconformity:

Unconformity assumed — surface essentially

horizontal for 0.25 mile where observed. 

Redwall Limestone: 

Horseshoe Mesa Member: 

Limestone, light-olive-gray, aphanitic, mediumbedded; forms rough, receding ledges at top 

of cliff ————————————————— Not measured
422 THE SUPAI GROUP OF GRAND CANYON

Section 11 

SHINUMO TRAIL

[Measured northeast of trail in Muav Canyon, western part of Shinumo 

Amphitheater]

Feet

Hermit Shale:

Siltstone, red-brown, shaly to thin-bedded; 

forms slope ——————————————————— 7.0

Contact:

Contact even and flat where exposed.

Supai Group: 

Esplanade Sandstone, main cliff unit:

Sandstone, moderate-orange-pink with 

reddish-brown speckles (lower and middle 

part), pinkish-gray, locally white (upper 

part); very fine to fine-grained, calcareous 

except in lower part; weathers to moderatereddish-orange; forms series of massive, 

rounded ledges ————————————————— 55.0

Sandstone, moderate-orange-pink, very fine 

grained (scattered fine grains), thick-bedded 

(2-4 ft); calcareous; weathers to rounded 

ledges —————————————————————— 15.5

Concealed slope; probably shaly, red-brown

siltstone ————————————————————— 7.5

Sandstone, moderate-orange-pink with moderate-reddish-brown speckles, very fine 

grained, calcareous, resistant; crossstratified on medium to large scale, tabularand wedge-planar types; forms ledge ———— 14.0

Sandstone, pale-reddish-brown, flat-bedded; 

very fine grained, calcareous; forms bench — 8.0

Sandstone, moderate-orange-pink with moderate-reddish specks, very fine grained, 

limy, calcareous; cross-stratified; forms 

resistant cliff —————————————————— 18.5

Sandstone, moderate-orange-pink, calcareous, 

very fine grained, silty, friable; crossstratified on small to medium scale; beds 1-2 

ft thick; forms weak cliff ——————————— 12.5

Siltstone, pale-red, calcareous, shaly to thinbedded; forms slope —————————————— 5.5

Siltstone, red-brown, resistant; cross-stratified 

on medium scale; forms cliff ————————— 27.0

Siltstone, deep-red-brown, flat-bedded, thinbedded (2-6 in.); forms recess ———————— 6.5

Sandstone, moderate- to orange-pink, calcareous, very fine grained, cross-stratified on 

large scale, planar type; forms cliff with 

sheer face ———————————————————— 13.5

Section 11—Continued 

SHINUMO TRAIL—Continued

Supai Group—Continued 

Esplanade Sandstone, main cliff unit—

Continued

Siltstone, pale-red; includes scattered very 

fine grains; calcareous, flat-bedded, thinbedded (2-6 in.); contains worm borings 

with muddy films; forms recess ————————

Sandstone, red-brown, very fine grained, limy, 

resistant; cross-stratified on medium to 

large scale, tabular- and wedge-planar types; 

locally weathers with black varnish; forms 

cliff ______________________

Sandstone, moderate-reddish-orange, very 

fine grained (includes scattered fine grains), 

calcareous, flat-bedded, shaly to thinbedded (6-12 in.); forms bench or slope ———

Sandstone, pale-red, calcareous, very fine 

grained, cross-stratified on medium scale, 

wedge-planar type; bedding units thick (2-8 

ft); weathers dark-gray; forms base of main

Feet

2.0

24.0

10.5

12.0

Total main cliff unit, Esplanade

Sandstone ——————————— 232.0

Esplanade Sandstone, basal slope unit: 

Mudstone, pale-red, structureless, silty; contains scattered very fine grains; calcareous, 

moderately resistant; forms rounded ledge — 5.0 

Concealed slope ————————————————— 10.5 

Siltstone, moderate-reddish-orange; contains 

scattered very fine grains; calcareous; weakly cross-stratified on medium scale, planar 

type, in lower part; appears structureless 

above; weathers to red surface, locally with 

black varnish; forms massive rounded cliff — 45.0 

Concealed slope ————————————————— 11.0 

Siltstone, pale-red with irregular concretionary 

masses of very pale orange, calcareous; contains scattered very fine sand and a few 

widely scattered pebbles of gray limestone, 

0.5-1 in. in diameter; massive; forms ledge — 1.5 

Conglomerate, pale-reddish-brown; calcareous; forms massive ledge ——————————— 2.5 

Gravel: gray limestone, pink and gray sandstone, and red-brown siltstone; subangular to subrounded; spheroidal to 

ellipsoidal; average diameter 0.5-1 in., 

maximum 1.5 in. 

Matrix: red-brown siltstone to sandstone.

Total basal slope unit, Esplanade Sandstone ———————— 75.5 

Total Esplanade Sandstone ——— 307.5
MEASURED STRATIGRAPHIC SECTIONS 423

Section 11—Continued 

SHINUMO TRAIL-Continued

Unconformity:

Erosion surface at base of conglomerate assumed; base not exposed in this area.

Section 12 

THUNDER RIVER TRAIL

[Measured in Fishtail Canyon about 3 miles from Thunder River Trail]

Section 12—Continued 

THUNDER RIVER TRAIL-Continued

Feet

Hermit Shale:

Lower ledge-slope unit:

Siltstone, pale-reddish-brown, 

bedding, shaly; forms slope.

horizontal

Sandstone, grayish-orange, very fine grained 

(subrounded); unit contains medium-scale, 

wedge-planar, cross-strata near base; largescale, tabular-planar cross-strata near top; 

stratification locally etched out on exposure; 

surface weathers to rounded hills forming 

Esplanade bench ————————————

Sandstone, grayish-orange-pink, very fine 

grained (angular); locally contains medium 

grains (rounded); unit prominently crossstratified (locally tabular-planar type crossstrata, large-scale, 60-70 ft long; elsewhere 

wedge-planar, cross-strata; structures etched 

out in fine detail); total weathers to mounds 

and odd erosional forms —————————

Feet

Unconformity:

Channels 37.5 ft deep in upper surface of Supai 

filled with Hermit Shale.

Supai Group: 

Esplanade Sandstone, main cliff unit:

Sandstone, very pale orange to pale-reddishbrown, very fine grained; contains mediumscale, wedge-planar, cross-stratification at 

base; large-scale, tabular-planar crossstratification near top; cross-strata not 

prominent, but locally etched by weathering; forms resistant cap rock ————————— 10.0

Sandstone, moderate-reddish-brown, very fine 

grained, thick-bedded (2-6 ft); structureless 

within beds; bottom of unit fine-grained 

(subrounded) sand; total weathers to rough, 

irregular surface ———————————————- 27.5

76.0

24.0

Supai Group—Continued 

Esplanade Sandstone, basal slope unit—

Continued

Sandstone, pale-red to grayish-orange-pink, 

very fine grained (subangular); unit thinbedded at base (1-3 ft); very thick bedded in 

middle and at top (5-20 ft); in part, crossstratified; unit weathers to rounded surfaces 

of grayish-orange-pink; forms massive cliff 

with wide bench at base ——————————— 55.0

Sandstone, grayish-orange-pink, very fine 

grained, calcareous; thick-bedded (2-4 ft) 

with sets of medium-scale, tabular-planar 

cross-stratification; weathers to light-gray, 

rounded surface; retreats from underlying 

ledge to form shelf ——————————————— 17.0

Sandstone, grayish-pink, very fine grained, 

very calcareous; contains prominent, smallto medium-scale, wedge-planar crossstratificaiton; weathers yellowish-gray; 

forms cap above extensive shelf ——————— 14.5 

Total main cliff unit, Esplanade

Sandstone —-—-————-—— 224.0

Esplanade Sandstone, basal slope unit:

Siltstone, pale-red, calcareous, shaly; mostly 

concealed; forms slope ———————————— 15.0

Sandstone, pale-reddish-brown at base, grading 

upward into moderate-reddish-orange, very 

fine grained; grains angular to subrounded; 

unit thick- to very thick bedded at base (2-8 

ft); grades upward to thin beds (0.5-2 ft); 

upper part moderate-reddish-orange, weakly cross-stratified; contains worm borings; 

forms resistant major cliff; lowest continuous sandstone bed above erosion channel — 60.5

Sandstone, pale-reddish-brown, very fine 

grained, structureless; contains clay balls 

(0.25-0.5 in. diameter); weathers to rounded 

boulders; forms filling along margins and in 

upper part of buried channel ————————— 7.5

Sandstone, pale-reddish-brown, very fine 

grained; grains subrounded; thin-bedded 

(0.5-1 ft); forms filling in lower part of 

buried channel; weathers to weak ledges —— 4.0

Conglomerate, moderate-reddish-orange, locally greenish-gray; forms distinctive marker 

at base of upper cliff —————————————— 1.0 

Matrix: moderate-reddish-orange siltstone. 

Gravel: as large as 1 in. in diameter; mostly 

well-rounded; composed of grayish-red 

siltstone and greenish-gray limestone.
424 THE SUPAI GROUP OF GRAND CANYON

Section 12—Continued 

THUNDER RIVER TRAIL-Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, main cliff unit—

Continued

(Detailed description of conglomerate, obtained 

one-half mile west of measured section.)

Conglomerate, moderate-reddish-orange; forms

distinctive marker at base of upper cliff ———— 2.5 

Matrix: greenish-gray, silty limestone. 

Gravel: locally derived pebbles; mostly 

0.25-1 in. diameter; maximum 3.5 in.; 

mostly well-rounded but some angular; 

oriented in crude layers; ellipsoidal pebbles with long axis horizontal; composed 

mostly of moderate-reddish-orange siltstone; some greenish-gray limestone. ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 88.0 

Total Esplanade Sandstone ——— 312.0

Unconformity:

Surface of erosion: contains channel as deep 

as 12 ft; filled with structureless red limy 

mudstone on north side of erosion pocket; 

unoriented shaly slabs on channel side; inner 

part of channel contains limestone pebbles, 

1-2 in. diameter, in red mudstone matrix. 

Wescogame Formation, slope unit:

Sandstone, pale-reddish-brown, very fine 

grained (grains subrounded), laminated 

(0.25-0.5 in.); in part, thin-bedded (1-2 ft); 

contains abundant cusp ripple marks; forms 

prominent slope with small ledges —————— 33.0

Siltstone, pale-red, very limy; weathers to 

dark-gray; forms prominent ledge —————— 5.0

Siltstone, pale-red; shaly at base; grades upward into platy limestone; forms slope or 

bench —————————————————————— 11.0 

Total slope unit, Wescogame

Formation ——————————— 49.0

Wescogame Formation, cliff unit:

Sandstone, grayish-red, fine-grained, mediumbedded (1-4 ft); locally contains tabularplanar cross-stratification; weathers to 

rounded top; forms cliff ———————————— 27.5

Sandstone, grayish-orange-pink, very fine 

grained (angular grains), horizontallybedded; bedding weakly developed; forms 

bench —————————————————————— 3.0

Section 12—Continued 

THUNDER RIVER TRAIL-Continued

Feet

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued 

Sandstone, grayish-orange-pink, fine-grained; 

contains some very fine grains (subrounded); 

unit very resistant, locally friable; thickbedded (1-4 ft); contains some tabularplanar cross-bedding; weathers to rounded 

knobs on top with black varnish; forms 

resistant cliff —————————————————— 30.5 

Conglomerate, fills erosion channels ————— 0.5-15.0 

Total cliff unit, Wescogame

Formation ——————————— 76.0 

Total Wescogame Formation —— 125.0

Manakacha Formation, slope unit:

Sandstone, pale-reddish-brown, very fine 

grained (subangular to angular); includes 

2-ft thick, structureless, weak ledge; grades 

upward into pale-reddish-brown, silty, 

medium-bedded mudstone; beds irregular, 

very weak; unit contains limy concretions at 

top; forms weak slope ————————————— 20.5

Sandstone, moderate-orange-pink, finegrained; contains large-scale, planar crossstratification and, locally, medium- to largescale, wedge-planar cross-stratification 

(10-40 ft); very thin bedded (0.25-2 in.); 

weathers to pinkish-gray; forms slope or 

weak receding cliff ——————————————— 34.0

Sandstone, pale-reddish-brown, very fine 

grained (grains subrounded), friable; 

horizontally-bedded; thin-bedded or shaly; 

beds weakly developed; unit includes siltstone beds with Rivularites, worm trails, 

shrinkage cracks, parallel ripple marks, rain 

pits, and poorly preserved ferns; forms 

recess under minor cliff ———————————— 7.5 

Total slope unit, Manakacha

Formation ——————————— 62.0

Manakacha Formation, cliff unit:

Sandstone, moderate-reddish-orange, very fine 

grained (subrounded to angular), friable; 

contains prominent, large-scale, tabularplanar cross-stratification (40-60 ft long); 

weathers to rounded surface; forms upper 

part of cliff ——————————————————— 62.0

Sandstone, grayish-orange-pink, very fine 

grained (subrounded), silty, calcareous; contains jasper lenses; forms resistant cliff ———— 9.5
MEASURED STRATIGRAPHIC SECTIONS 425

Section 12—Continued 

THUNDER RIVER TRAIL-Continued

feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Mudstone, pale-reddish-brown, limy, thickbedded (2-6 ft); beds weather with closely 

spaced parting planes (1-2 in.); rock grades 

upward into alternating units of palereddish-brown, very fine grained (subangular grains), limy, thick-bedded sandstone; contains large-scale, tabular-planar 

cross-stratification, and pale-reddish-brown, 

very thin bedded (2-12 in.) mudstone; total 

forms major cliff ———————————————— 60.5 

Limestone, pale-red to light-brownish-gray, 

silty (35 percent); contains tabular-planar 

cross-stratification; forms recess under maLimestone, yellowish-gray; contains jasper; 

forms three resistant, very thick bedded 

ledges (5-10 ft); separated by grayish-red

mudstone recesses (1-2 ft); total forms resistant cliff ———————————————

cliff

28.0

Total cliff unit, Manakacha

Formation ——————————— 164.0 

Total Manakacha Formation —— 226.0

Watahomigi Formation, upper slope unit:

Limestone, grayish-red; insoluble residue 

(40 percent); moderately resistant; contains 

mudstone lenses; alternates with grayishred, structureless mudstone; develops spheroidal weathering; total forms slope ————— 14.5

Limestone, grayish-red-purple, silty, massive; 

forms slope or rounded ledge ————————— 3.0

Dolomite, pale-red, silty, hard; black cliff

continuous with underlying unit ——————— 6.5

Siltstone, pale-reddish-brown, scattered very 

fine grained sand (angular grains), massive; 

contains elongate, very pale orange siltstone 

lenses that suggest bedding throughout; 

forms lower part of massive ledge —————— 8.0

Limestone, dark-gray, aphanitic; contains

jasper bands; forms cliff ——————————— 7.5

Mudstone, grayish-red, structureless; forms

C|OT}P ——————————————————————————————————*—_ 7 0

Limestone, light-brownish-gray; forms ledge — 3.0 

Siltstone, pale-reddish-brown (angular grains); 

contains several silty limestone ledges (2-4 

in.); upper portion contains limestone concretions; forms slope —————————————— 22.0

Section 12—Continued 

THUNDER RIVER TRAIL—Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit—

Continued

Limestone, pale-red, aphanitic; contains abundant jasper bands; with underlying 9 ft of 

mudstone forms cliff ———————————

Mudstone, pale-red, shaly; includes scattered 

sand grains (angular); contains abundant 

ellipsoidal mud concretions (1-3 in. wide); 

shaly beds wrap around concretions; forms 

conspicuous ledge ———————————

Mudstone, pale-red, shaly, limy; forms slope 

or recess ——.—-————————————••——-—

Limestone, medium-light-gray; weathers to 

rounded surface; forms resistant ledge ———

Mudstone, pale-red, shaly; forms slope ———

Limestone, greenish-gray, silty (angular grains); 

contains angular fragments of grayish-red 

mudstone; forms ledge —————————

Mudstone, grayish-red, shaly, silty (angular 

grains); contains several thin (2-6 in.) limestone ledges; forms slope ————————

Conglomerate, pale-red; forms key bed; forms

Matrix: pale-red siltstone. 

Gravel: composed of white and lightgreenish-gray quartz and chert, and palered jasper pebbles; 0.25-0.5 in. diameter; 

subangular to angular; densely packed.

Total upper slope unit, Watahomigi Formation —— 

Watahomigi Formation, middle cliff unit:

Sandstone, medium-light-gray, very fine 

grained; insoluble 93 percent; gnarly; forms

Limestone, medium-light-gray, aphanitic; includes much fine-grained sand; contains 

jasper; forms ledge ———————————•

Limestone, medium-light-gray, aphanitic; contains small siliceous(?) rods or spines; forms 

ledge —————————————————

Mudstone, light-brownish-gray, silty, structureless, calcareous; forms slope ——————

Limestone, light-olive-gray, aphanitic; locally 

contains stromatolitic structure; weathers to 

slope or rounded ledges —————————

Limestone, light-brownish-gray, very resistant; 

contains bands of jasper and patches of palered siltstone near top; forms ledge ——-

Total middle cliff unit, Watahomigi Formation ———————

feet

2.5

9.0 

2.0

2.5 

2.0

2.0 

11.0

98.5

6.0

2.0 

2.5

8.5

3.0 

25.0
426 THE SUPAI GROUP OF GRAND CANYON

Section 12—Continued 

THUNDER RIVER TRAIL-Continued

Feet

Supai Group—Continued 

Watahomigi Formation, lower slope unit:

Mudstone, pale-reddish-brown, silty, brittle, 

structureless; slope at base (lower 16.5 ft) 

largely concealed; upper portion (11 ft) 

forms weak slope ———————————————— 27.5

Mudstone, grayish-red, silty, locally sandy 

(angular grains); weakly bedded; forms 

slopes; alternates with grayish-red, finegrained, angular-grained sandstone; forms 

crumbly ledges ————————————————— 13.0

Siltstone, dark-reddish-brown, sandy (subrounded grains), structureless to weakly 

bedded; contains grayish-red mud peloids; 

forms slope ——————————————————— 16.5

Total lower slope unit, Watahomigi Formation ——————— 57.0 

Total Watahomigi Formation — 180.5 

Total Supai Group ———————— 843.5

Unconformity:

Irregular erosion surface at top of Redwall 

Limestone filled with mudstone of Supai 

Group. Erosion surface shows as much as 5 

ft of relief in 25-ft lateral distance.

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, yellowish-gray, aphanitic; irregularly bedded; bedding planes and solution 

holes filled with red mudstone to depth of 10 

ft; forms cliff.

Section 13 (part)—Continued 

TOPOCOBA TRAIL-Continued

Contact:

Uppermost bed of massive sandstone of Supai; 

overlain by shaly siltstone of Hermit Shale. 

Large erosion channel at this horizon onefourth mile farther west, filled with Hermittype siltstone.

Supai Group:

Esplanade Sandstone, upper cliff-slope and main 

cliff units:

Sandstone, white, calcareous, very friable, 

cross-stratified (tabular-planar type); forms 

cap of platform —————————————

Sandstone, red-brown to white, very fine 

grained, medium- to thick-bedded (1-10 ft), 

cross-stratified, ledge-forming; very limy 

with thin siliceous rods near top; alternating 

with deep-red-brown, structureless, brittle 

mudstone, in lower part; shaly in upper 

part; contains worm trails at 35 ft above 

base, plant fragments and worm borings 

near top —•—-—~—-—-TM—~~—"•—~~—————

Siltstone, bright-red-brown, flat-bedded, 

medium-bedded (1-3 ft); forms bench at top 

of main cliff ———————————————

Feet

Section 13 (part) 

TOPOCOBA TRAIL

[Along south side of trail, 1 mile west of Topocoba Hilltop; lower part of 

Supai Group not measured]

Hermit Shale:

Siltstone, weak-reddish-brown, argillaceous, 

friable; forms slope; grades upward into 

light-brown, thick-bedded (1-3 ft) siltstone;

5.5

71.5

9.5

forms ledge; total 25.0

Siltstone, red-brown, very calcareous, thickbedded (4-15 ft); cross-stratified; weathers 

to sheer cliff with black varnish on surface; 

forms upper part of main cliff ———————— 60.5

Mudstone, deep-red-brown; displays concretionary structure; forms bench or undercut — 3.0

Sandstone, bright-red, very fine grained, thickbedded (2-15 ft); cross-stratified on medium 

to large scale; forms massive cliff; resistant — 52.0

Siltstone, red-brown, thin-bedded (1-3 ft), 

flat-bedded; relatively weak; locally forms 

bench —————————————————————— 11.0

Sandstone, white, very fine grained, thickbedded, cross-stratified on large scale (30-40 

ft), tabular-planar type; forms weak ledge or 

bench; makes conspicuous color band midway in Esplanade ———————————————— 16.5

Sandstone, red-brown, very fine grained, 

cross-stratified on medium to large scale 

(5-30 ft, tabular-planar and wedge-planar); 

weathers red-brown to dark-brown; forms 

sheer cliff —————————____——- 24.0
MEASURED STRATIGRAPHIC SECTIONS 427

Section 13 (part)—Continued 

TOPOCOBA TRAIL—Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope and 

main cliff units—Continued 

Siltstone, red-brown, structureless; weathers 

to spheroidal surface; locally forms ledges 

with limestone nodules; forms base of main 

cliff-——-———-----——————-—-—— 8.0 

Total upper cliff-slope and main 

cliff units, Esplanade Sandstone —————————————— 261.5

Esplanade Sandstone, basal slope unit:

Siltstone, deep-red-brown, argillaceous, brittle;

forms slope; undermines main cliff above —— 8.5 

Sandstone, pale-red-brown, very fine grained, 

friable, cross-stratified (low-angle, mediumscale); much concealed ———————————— 11.0 

Siltstone, red-brown to gray, massive, friable;

weathers to rounded ledge —————————— 16.5 

Siltstone, bright-red-brown, shaly to thinbedded; forms slope —————————————— 8.5 

Sandstone, red-brown to gray, very fine 

grained, massive, resistant, structureless; 

weathers to rounded, red ledge ——————— 5.5 

Siltstone, bright-red-brown, shaly to thinbedded; fills channels in conglomerate; 

forms weak ledge or slope ——————————— 27.5 

Conglomerate, red-brown to gray; gravels in 

beds and lenses (0.5-12 in. thick) with redbrown siltstone partings; total is lenticular, 

wedging out laterally in about 100 ft ———— 1.0-4.0 

Matrix: siltstone, red-brown, like 27.5-ft

siltstone above.

Gravel: Composition—light-gray, aphanitic 

limestone, olive-gray limestone with thin 

siliceous rods, dark-gray limestone, darkred-brown, calcareous siltstone, redbrown siltstone, chocolate-brown siltstone, pink siltstone; Size—mostly 0.25-1 

in. diameter, maximum 18 by 9 in.; 

Shape—limestone mostly subangular, 

some angular; siltstones rounded. ____ 

Total basal slope unit, Esplanade Sandstone ———————— 81.5 

Total Esplanade Sandstone ——— 343.0

Wescogame Formation, slope unit:

Siltstone, white to gray, calcareous, structureless, forms massive rounded ledge —————— 

Underlying units not measured.

4.0

Section 14 

HAVASU CANYON

[Watahomigi Formation measured on west side of canyon at Navajo 

Falls; upper part of group measured along Apache Trail, northeast 

of Supai village]

Feet

Hermit Shale:

Siltstone, moderate-reddish-orange, thinbedded, ledge-forming: and grayish-red, 

structureless, slope-forming mudstone; total 

forms ledge-slope member —————————— 170.0

Unconformity:

Erosion surface with relief of 44 ft. Consists of 

isolated plateaus of resistant sandstone that 

rise above generally flat surface of formation. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope unit:

Sandstone, moderate-orange-pink, massive, 

forms residual hill or mesa, rises above 

general surface at 0.5 mile north —————— est. 40.0

Sandstone, moderate-orange-pink, very fine 

grained, thick-bedded, massive; forms receding, rounded ledges ———————————— 77.0 

Total upper cliff-slope unit, Esplanade Sandstone —————— 117.0 

Esplanade Sandstone, main cliff unit:

Sandstone, moderate-orange-pink, fine- (24 

percent) to very fine grained (57 percent), 

calcareous, very thick bedded (10-20 ft), 

massive; locally weathers to pinkish-gray; 

forms massive cliff ——————————————— 63.0

Sandstone, moderate-reddish-orange, very fine 

grained, friable; contains medium-scale, 

wedge-planar cross-stratification (planes 

1-10 ft long) —~—————————-——- 27.5

Sandstone, moderate-reddish-orange, very 

fine grained, thin- to thick-bedded (1-4 ft); 

flat-bedded; less resistant than underlying 

sandstone unit; upper portion contains 

several 2-3 ft beds of pale-red, calcareous 

sandstone; forms cliff or receding ledges —— 38.5

Sandstone, pale-reddish-brown, fine- to very 

fine grained, calcareous, friable; and 

moderate-reddish-orange, very fine grained, 

calcareous, silty sandstone; and pale-red, 

silty, clastic limestone; grains etched out on 

surface; the three overlying sandstone units 

form cliffs separated by prominent partingplanes; all four contain medium- to largescale cross-stratification; contain local festoon structures; weather with black varnish - 45.0
428 THE SUPAI GROUP OF GRAND CANYON

Section 14 — Continued 

HAVASU CANYON-Continued

Supai Group — Continued

Esplanade Sandstone, main cliff unit — Continued

Sandstone, pale-reddish-brown, very fine

grained, calcareous (26 percent), silty (19

percent), flat-bedded; forms recess between

inan"\T*

1 1 LdJ \Jl

Feet

9.0

Sandstone, moderate-reddish-orange, very fine 

grained (76 percent), calcareous (25 percent); 

contains subangular to subrounded grains; 

massive, structureless; contains parting zone 

of flat-bedded siltstone that separates unit 

into two parts; forms base of Esplanade cliff -_ 24.5

Total main cliff unit, Esplanade

Sandstone ——————————— 207.5

Esplanade Sandstone, basal slope unit:

Sandstone, moderate-reddish-orange, very 

fine grained (rounded to subrounded); calcareous, thin-bedded (2-3 ft), structureless; 

contains several pale-red, calcareous siltstone partings; forms recess below massive

cjj££ ___________________________________ 13 Q

Sandstone, moderate-reddish-orange, very fine 

grained, silty; very thin to thin-bedded (1-4 

in.); contains irregular to festoon-type structures; forms weak ledge ———————————— 1.0

Conglomerate, pale-red, irregularly bedded; 

fills channels in underlying unit; forms resistant ledge —————————————————— 1-2.5 

Matrix: pale-red, fine-grained sand. 

Gravel: diameter of most pebbles 0.25-1 in.; 

maximum diameter 3 in.; pebbles subrounded to rounded; poorly sorted; composed of olive-gray, light-gray, and palered limestone and siltstone.

Sandstone, moderate-reddish-orange, very fine 

grained; some fine-grained; silty, very thin 

to thin-bedded (1-4 in.); contains irregular 

to festoon-type structure; forms slope with 

weak ledges —————————————————— 16.0

Limestone, light-brownish-gray, aphanitic to 

very fine grained; surface markings suggest 

stromatolitic structures; contains thin, locally developed bands of chert; forms two thin 

beds (6 in. and 20 in.) separated by gray siltstone (20 in. thick) and capped by 8-in. bed 

of concretionary limestone —————————— 4.5

Sandstone, grayish-orange-pink, very calcareous, very fine grained; very thin bedded 

(0.5-2 in.); flat-bedded; forms receding

Section 14—Continued 

HAVASU CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, basal slope unit—

Continued

Limestone, pale-red, concretionary, very hard, 

includes grayish-red silt; forms rounded 

ledge or slope —————————————————

Sandstone, pale-reddish-brown, very fine 

grained, silty; grains iron-coated; brittle, 

structureless; forms slope ———————————

Sandstone, pale-red, very fine grained, silty, 

structureless; crumbly; forms slope —————

Sandstone, grayish-pink, very fine grained 

(angular), silty, thin-bedded (1-2 ft); weathers to rounded ledge ——————————————

Sandstone, grayish-orange-pink, very fine

Feet

5.0

2.5 

2.0

5.0 

4.5 

42.0 

5.5

T 7 ' J./ ,^

grained, calcareous, friable; forms slope ——

Sandstone, like overlying 4.5-ft sandstone but

filling channel —————————————

Conglomerate, pale-red to light-gray, forms 

thin bed at bottom of erosion channel ———— 

Matrix: pale-red to light-gray silt. 

Gravel: diameter range 0.5-2 in.; maximum 

diameter 3 in.; mostly subrounded, few 

rounded, some well-rounded; composed 

of light-gray limestone, reddish-brown 

and purplish-gray siltstone. ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 79.0 

Total basal slope unit with basal 

channel sand, Esplanade Sandstone —————————————— ±z*±. • \)

Total Esplanade Sandstone ——— 14Q3.5

Unconformity:

Channel 47.5 ft deep and 144 ft wide at top; cut 

into massive and cross-bedded, gray sandstones; filled largely with thin-bedded, pink 

sandstone, conglomerate at bottom.

Wescogame Formation, slope unit: absent.

Wescogame Formation, cliff unit:

Sandstone, pinkish-gray (with small rustybrown spots) at base, grading upward to 

pale-red, fine- to very fine grained; calcareous; thin-bedded (2-4 ft) at base and at 50 ft 

above base; elsewhere very thick bedded 

(10-15 ft); thinner beds contain flat laminae, 

thicker beds contain large-scale, planar 

cross-stratification (as much as 50 ft long); 

contains two dark-reddish-brown lenses of 

flat-bedded siltstone at 55 ft and 82.5 ft 

above base; weathers with dark-brown varnish; forms massive cliff ——————————— 138.5

1Thickness of channel sands not included in total Supai Group
MEASURED STRATIGRAPHIC SECTIONS 429

Section 14—Continued 

HAVASU CANYON-Continued

Section 14—Continued 

HAVASU CANYON-Continued

Feet

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued 

Mudstone, light-brown, noncalcareous, thinbedded (0.5-2 ft); flat-bedded; contains 

abundant Rivularites; forms recess at base of 

ciirr ———————————————————————————————————————— o. o

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, shaly to structureless; 

forms slope with weak ledges; fills upper 

part of large channel in older Pennsylvanianage rocks ———————————————————— 30.5 

Sandstone, moderate-reddish-orange; fine- to 

very fine grained, calcareous, flat-bedded; 

includes mud pellets and scattered pebbles 

near base; forms slope; fills channel bottoms 22.0 

Total cliff unit, Wescogame Formation ————————————— 147.0 

Total cliff unit with basal channel sand, Wescogame Formation ——————————- 199.5

Total Wescogame Formation —— 1147.0

Unconformity:

Wide channels with rounded bottoms, cut to 

depths as much as 80 ft in cross-stratified 

sandstones of older Pennsylvania age (locally 52.5 ft deep); exposed at this horizon at 

many places in vicinity.

Feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Siltstone, pale-reddish-brown, calcareous, 

shaly to thin-bedded; grades upward into 

pale-red-purple, very fine grained, locally 

massive and thick-bedded sandstone, with 

limestone lenses; total forms receding ledges - 59.5

Limestone, grayish-red; includes much very 

fine grained sand (insoluble 40 percent); 

cross-bedded (tabular-planar); sets mediumthick (1-3 ft); contains jasper near top; 

forms receding ledges ————————————— 16.5

Limestone, medium-light-gray; includes scattered fine- to very fine grained sand; crossstratified (medium scale); contains abundant 

chert and jasper; weathers to rough black 

surface; forms prominent massive cliff ———— 13.0

Limestone, light-brownish-gray with pale-red 

blotches, thick-bedded (4-15 ft); contains 

jasper layers and veins near base; crossstratified (medium-scale); forms cliff ————— 39.5

Siltstone, dark-reddish-brown, calcareous (22 

percent); crumbly; rests on irregularly channeled surface of bright-reddish-brown mudstone ————————————————————— 2.0-10.0 

Total cliff unit, Manakacha Formation —————————————181.0 

Total Manakacha Formation —— 254.5

Manakacha Formation, slope unit:

Sandstone, moderate-reddish-orange, fine- to 

very fine grained; cross-stratified on large 

scale (as much as 40 ft long); includes 

grayish-red, muddy, noncalcareous, very 

fine grained sandstone near base; total forms 

clone ________________________ 73 5 

Total slope unit, Manakacha

Formation, pre-erosion ———— 73.5

Manakacha Formation, cliff unit:

Limestone, grayish-orange-pink, very fine 

grained, (subrounded), silty, (insoluble 33 

percent); cross-stratified on small to medium 

scale; weathers with black varnished surface; forms massive, resistant cliff with 

rounded edges ————————————————— 22.0

Sandstone, pale-red-purple, very fine grained, 

limy, strongly cross-stratified (tabularplanar, sets 2-3 ft thick); contains some 

limestone lenses; forms cliff or receding 

ledge —————————————————————— 20.5

1Thickness of channel sands not included in total Supai Group

Erosion surface:

Structureless reddish-brown siltstone surface is channeled to depths of 1-2 ft at irregular intervals and locally entirely removed by erosion.

Watahomigi Formation, upper slope unit:

Concealed slope ————————————————— 5.5

Sandstone, pale-reddish-brown, very fine 

grained, noncalcareous, structureless; forms 

conspicuous marker bed; weathers into 

rounded ledge overlying weak cliff ————— 4.0

Siltstone, grayish-red, muddy, very limy; 

wavy- to flat-bedded; laminated (0.13-0.5 

in.); contains thin jasper lenses at top; forms 

weak cliff ————————————____ 27.5

Mudstone, pale-red, silty, calcareous; wavyto flat-bedded; laminated (0.13-0.5 in.); 

forms steep slope ———————————————— 16.5

Concealed slope; probably grayish-red mudstone —————————————————————— 22.0
430 THE SUPAI GROUP OF GRAND CANYON

Section 14—Continued 

HAVASU CANYON-Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit—

Continued

Conglomerate, consisting of intraformational 

limestone pebble lenses; in medium-darkgray, concretionary limestone; contains 

some jasper; forms rounded ledge or steep 

slope; marks base of Atokan-age strata 

Total upper slope unit, Watahomigi Formation ——————

Watahomigi Formation, middle cliff unit:

Limestone, very light gray, magnesian, very 

silty; contains abundant elongate concretions and lenses of gray chert; forms ledge at 

top of series ————————————————

Siltstone, dark-gray, friable; forms bench ———

Limestone, very light gray, silty, fine-grained; 

thick-bedded (2-6 ft); contains thin jasper 

layers and crosscutting veins throughout; 

forms series of ledges separated by thin 

(0.5-1 ft) mudstone beds —————————

Limestone, light-brownish-gray, dolomitic; interbedded with black mudstone containing 

network of calcite veins; weathers to concretionary spheres; forms slope ————————

Limestone, medium-gray, fine-grained; contains abundant jasper layers and secondary 

calcite fillings along fractures; weathers to 

rough surface; forms ledge —————————

Limestone, light-brownish-gray, silty; weathers brown; forms weak ledge with straight

Limestone, grayish-red, irregularly bedded; interbedded with brown mudstone; forms

Total middle cliff unit, Watahomigi Formation ————— 

Watahomigi Formation, lower slope unit:

Conglomerate, consisting of lenses of dark 

intraformational limestone pebbles (maximum, 0.5 in.) at top of unit and beds of 

medium-light-gray, silty limestone that contain local jasper lenses and form series of 

resistant ledges ——————————————

Mudstone, pale-red-purple, slightly calcareous, crumbly; forms slope —————————

Limestone, medium-light-gray, fine-grained; 

contains thin, irregular jasper layers; consists of a single very thick bed; forms resistant cliff ———————————————

Concealed, talus slope ——————————

Feet

8.5

84.0

9.5 

2.0

14.5

2.5

6.0

2.5

—- 2.0

39.0

5.5 

5.0

6.5 

33.0

Section 14—Continued 

HAVASU CANYON-Continued

Supai Group—Continued 

Watahomigi Formation, lower slope unit— 

Continued 

Siltstone, pale-red, shaly; largely concealed;

Conglomerate, pale-red, very thick bedded; 

forms resistant ledge —————————————

Matrix: pale-red, fine- to very fine grained

sandstone.

Gravel: mostly 0.25-0.75 in. diameter; angular to subangular; composed of darkreddish-brown, moderate-orange-pink, 

and very dark red chert and flint. 

Concealed slope ——————————————

Siltstone, pale-red, shaly, fissile; includes laminated limestone beds (0.25-0.5 in.) scattered 

throughout; forms slope ———————————

Conglomerate, dark-reddish-brown; thinbedded to shaly; forms ledge ————————

Matrix: pale-red, very fine grained sandstone and siltstone.

Gravel: abundant 0.13-0.25 in. diameter 

pebbles, with a maximum diameter of 0.5 

in.; composed of very light gray, pale-red, 

and dark-gray chert; contains abundant 

brachiopods (Composita sp.) at top of 

unit.

Conglomerate, pale-red, massive; forms ledge — 

Matrix: pale-red mudstone. 

Gravel: mostly 3-6 in. diameter, with maximum diameter of 8 in.; irregularly shaped 

with random orientation; composed of 

light-olive-gray and dark-reddish-brown 

chert.

Limestone, yellowish-gray, aphanitic; thickbedded (2-4 ft); weathers to very pitted surface; forms ledge ————————————

Conglomerate, dark-reddish-brown; contains 

much iron oxide; fills channel ———————— 

Matrix: dark-reddish-brown mudstone. 

Gravel: mostly 0.5-1 in. diameter, maximum diameter 4 in.; mostly angular; composed of chert. _ 

Total lower slope unit, Watahomigi Formation ———————_

Feet

11.0

2.5

8.0

6.0

3.0

3.0

5.5

3.0

92.0

Total Watahomigi Formation — 215.0 

Total Supai Group ——————— 1,010.0

Unconformity:

Channeled surface with 5-ft relief in 100 ft 

horizontal distance.
MEASURED STRATIGRAPHIC SECTIONS 431

Section 14—Continued 

HAVASU CANYON-Continued

Redwall Limestone:

Horseshoe Mesa Member: 

Limestone, yellowish-gray, aphanitic, thinbedded (1-2 ft); forms receding ledges.

Section 15 

NATIONAL CANYON

[In National Canyon, Hualapai Indian Reservation. Watahomigi 

measured on west side above the gorge formed by the Redwall 

Limestone; from Manakacha to Esplanade, measured on east side; 

Esplanade measured on west side of canyon]

Feet

Feet

Coconino Sandstone:

Sandstone, medium-light-gray, fine-grained;

cross-stratified on large scale; forms vertical

cliff. 

Sandstone, medium-light-gray, fine-grained,

thin-bedded; horizontal-bedding ——————— 2.0

Hermit Shale:

Siltstone, moderate-reddish-orange, weakly 

cemented; contains some very fine grained 

sand; forms ledges; alternating with palereddish-brown, brittle mudstone; forms 

crumbly slopes; ratio of ledge to slope is 3:1 — 275.0

Mudstone, pale-reddish-brown; forms crumbly 

slopes; alternating with moderate-reddishorange, blocky, poorly bedded siltstone; 

forms weak ledges; and bright-red, relatively 

resistant siltstone; forms rounded ledges (2-3 

ft thick); ratio of ledge to slope is 1:2 ————— 112.0

Mudstone, pale-reddish-brown, slope-forming; interbedded with moderate-reddishorange, thin- to medium-bedded (0.5-2 ft) 

siltstone; forms resistant ledges; ratio of 

ledge to slope is 1:5 ——————————————— 159.5

Total Hermit Shale —————— 546.5

Unconformity:

Large hill or mesa of Esplanade-type sandstone 

and siltstone rises 114 ft above general flat 

surface of Esplanade near place of measured 

section. Mesa top exposed for about 1,000 ft 

north-south along present canyon.

61.5

4.0

48.5

Section 15—Continued 

NATIONAL CANYON-Continued

Supai Group:

Esplanade Sandstone, upper cliff-slope unit: 

Sandstone, moderate-reddish-orange, very 

fine grained, friable, hard, medium-bedded 

(2-4 ft); forms massive, rounded ledges; 

resembles sandstone of Esplanade main cliff 

unit; includes a few parting units of flat, 

shaly siltstones; stands above general base of

Conglomerate, yellow-brown, thick-bedded; 

contains geodes of calcite; very resistant; 

forms prominent ledge ———————————— 

Matrix: fine-grained, moderate-reddishorange sand.

Gravels: Composition—light-gray, aphanitic limestone, chalky limestone, darkbrown siltstone, deep-reddish-brown claystone; Size—mostly 0.25-0.5 in. diameter, 

maximum 2 in.; Shape—rounded to subrounded.

Siltstone, pale-red, shaly, slope-forming; includes some ledges of thin-bedded (1-2 ft), 

friable, pale-reddish-brown, very fine 

grained sandstone forming weak ledges ——— 

Total upper cliff-slope unit, Esplanade Sandstone —————— 114.0

Esplanade Sandstone, main cliff unit:

(The upper surface of this sandstone forms 

contact with Hermit Shale across most of the 

exposed area).

Sandstone, grayish-orange-pink to moderatereddish-orange, very fine grained, calcareous (33 percent), friable, thick-bedded (3-15 

ft), weakly cross-stratified near top; forms 

massive rounded cliff (rim of Esplanade) —— 43.0 

Siltstone, moderate-reddish-orange, includes 

very fine grained sandstone, flat-bedded, 

crumbly, slope-forming; includes thin ledges 

of hard, cross-stratified sandstone (2-3 ft

Sandstone, grayish-orange-pink to palereddish-brown, medium- to very fine grained 

(bimodal); forms cliff of three massive units; 

lower and upper units, hard, flat-bedded; 

middle unit, friable, strongly cross-stratified; weathers with black varnish —————— 57.0

Siltstone, moderate-reddish-orange, very 

friable, platy; forms recess —————————— 5.0
432 THE SUPAI GROUP OF GRAND CANYON

Section 15—Continued 

NATIONAL CANYON-Continued

feet

Supai Group—Continued

Esplanade Sandstone, main cliff unit—Continued

Sandstone, grayish-orange-pink, very fine

grained, cross-stratified, tabular-planar, on

large scale (5-15 ft thick); forms part of high

cliff -__________._________„___________„_________„_____ 17.Q

Limestone, grayish-orange-pink; contains very 

fine grained sand; cross-stratified on 

medium scale (planar-type), medium thick 

(1-3 ft); forms basal part of high cliff ————— 19.5

Sandstone, pale-reddish-brown, very fine 

grained; includes silt; strongly cross-stratified, large-scale, planar-type; forms weak 

ledge below main cliff ————————————— 19.0

Sandstone, pale-red, very fine grained, friable; 

irregularly bedded to weakly crossstratified; forms receding ledges (1-2 ft 

thick) ——-—-----——————————— 7.5

Sandstone, moderate-reddish-orange, very fine 

grained, friable; cross-stratified on large 

scale, tabular-planar type; weathers red; 

forms rounded cliff continuous with underlying cliff ————————————————————— 19.0

Sandstone, pale-red, very fine grained with 

some silt, resistant; medium-thick units 

(2.5-5 ft); contains limestone concretions; 

weathers to black surface; forms rounded 

cliff __—_—_——„___———____—______________ 22.0

Sandstone, pale-reddish-brown and light-olivegray to white, fine- to very fine grained, 

friable; contains fragments and blocks of 

moderate-reddish-orange, aphanitic limestone; forms receding ledges ————————— 16.5

Sandstone, pale-red, fine- to very fine grained, 

limy; cross-stratified, medium-scale, tabular-planar; locally with primary recumbent 

structures; sets 3-4 ft thick; weathers to gray 

or black, pitted surface; forms rounded cliff - 9.0

Sandstone, pale-red, fine- to very fine grained, 

friable; weathers to weak ledge or slope ——— 12.0

Sandstone, moderate-reddish-orange, very fine 

grained, friable; prominent cross-stratification (festoon-type), medium-scale; forms

Total main cliff unit, Esplanade

Sandstone ——————————— 283.5

(Esplanade Sandstone basal slope unit measured 

on east wall of Canyon)

Section 15—Continued 

NATIONAL CANYON-Continued

Supai Group—Continued

Esplanade Sandstone, basal slope unit:

Siltstone, pale-red, thin-bedded, flat-bedded; 

forms slope or recess; includes two resistant 

ledges (2-3 ft thick) of hard, moderatereddish-orange, very fine grained sandstone -

Sandstone, moderate-reddish-orange, finegrained; weathers with rounded surface; 

erodes into large blocks; forms basal, resistdill or^ r-li(-f 1.1111 ——————————————— _ _ __________________________

Sandstone, moderate-reddish-orange, very 

fine grained, rubbly, concretionary, very 

calcareous; forms weak ledge or recess ———

Mudstone, dark-reddish-brown, brittle, 

crumbly; contains silt and some very fine 

grained sand; forms slope; includes two thin 

ledges of resistant siltstone and one ledge of 

conglomerate —————————————————

Sandstone, pale-red, very fine grained with 

some silt, calcareous; contains weakly developed cross-strata (large-scale, planar) and 

local thin (1-3 in.) flat beds; forms rounded, 

massive ledges with black varnish; consists 

of lowest continuous strata in Esplanade section ———————————————————-

Feet

15.0

9.0

3.0

16.5

-- 15.0

Channel rim:

Conglomerate, topmost bed filling channel at 

base of unit; similar to basal conglomerate 

but pebbles all small (maximum diameter 2 

in.) ——__—________________„___________.___________ 2.0

Sandstone, dark-reddish-brown, very fine 

grained, cross-stratified; forms resistant 

ledge; channel-fill deposit ——————————— 5.5

Sandstone, moderate-reddish-orange, very fine 

grained, platy, flat-bedded; forms slope; 

channel-fill deposit —————————————— 8.5

Sandstone, moderate-reddish-orange, very fine 

grained; cross-stratified on large scale, tabular-planar type; forms resistant ledge; channel-fill deposit ————————————————— 7.5

Sandstone, pale-reddish-brown, very fine 

grained, friable, thin-bedded (0.5-3 in.); 

forms slope, channel-fill deposit ——————— 9.0

Conglomerate, reddish-gray; forms massive 

ledge; basal deposit in channel 40 ft deep —— 8.0 

Matrix: red-brown, fine-grained siltstone.
MEASURED STRATIGRAPHIC SECTIONS 433

Section 15—Continued 

NATIONAL CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, basal slope unit— 

Continued 

Conglomerate—Continued

Gravel: Composition—purple limestone, 

light-gray limestone, red-brown siltstone, 

red jasper, pink laminated sandstone; 

Shape—rounded to subrounded, angular 

(jasper); Size—0.5 in. to 8 in. maximum 

dimension; Sorting—very poor.

Section 15—Continued 

NATIONAL CANYON—Continued

Feet

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued 

Sandstone, pale-reddish-purple, very fine 

grained, calcareous, weakly cross-stratified; 

weathers dark-brown; forms rounded, receding ledge —————————————————— 3.0

Total basal slope unit, Esplanade

Sandstone ————————— ^9.0

Total Esplanade Sandstone ——— ^96. 5

Unconformity, erosion surface marked by channel 40.5 ft deep and 85 ft wide, with steplike 

sides; cut into underlying limestone and sandstone units.

(From base of Manakacha Formation to Esplanade basal conglomerate measured on 

east side of canyon about 2 mi above head of 

Redwall gorge.) 

Wescogame Formation, slope unit:

Limestone, dark-reddish-brown, muddy (46 

percent); contains small spherical and rodlike siliceous inclusions; weathers to 

rounded, nodular surface; forms weak, receding ledges or slope ——————————— 11.0-27.5 

Total slope unit, Wescogame

Formation ——————————— 27.5

Wescogame Formation, cliff unit:

Sandstone, grayish-orange-pink, very fine 

grained (contains some fine grains); very 

calcareous, contains cross-strata, mediumto large-scale (wedge-planar); weathers 

pink-to medium-gray; forms weak receding

Sandstone, very pale orange, medium- to finegrained, calcareous, weakly cross-stratified 

(medium-scale); weathers generally palegray, locally black; forms rounded, moderately resistant ledges —————————————— 9.0

Sandstone, pale-red, very fine grained, very 

silty, prominently cross-stratified on large 

scale (30-40 ft long, tabular-planar); includes pale-red, calcareous siltstone with 

spheroidal weathering, forming 2-f t recess at 

22 ft up; weathers grayish-orange-pink;

Conglomerate, gray, speckled with white, 

ledge-forming ————————————————— 1.0

Matrix: sandy limestone, purple, finegrained.

Gravel: mostly white chert, some gray and 

brown chert, some brown siltstone; 

angular to subangular; average diameter 

0.13-0.5 in., maximum 1 in. ____

Total cliff unit, Wescogame Formation ————————————— 85.5 

Total Wescogame Formation —— 113.0

Manakacha Formation, slope unit:

Sandstone, pale-reddish-purple, contains much 

sand, medium- to thick-bedded (2-10 ft); 

ripple-marked and cross-stratified, mediumto large-scale (wedge-planar); weathers to 

black face with laminae etched out; forms 

massive cap on cliff —————————————— 22.0

3.5

Sandstone, pale-reddish-purple, very fine 

grained (angular grains), argillaceous, structureless; forms prominent recess with spheroidal weathering ———————————————

Limestone, grayish-orange-pink, sandy (45 

percent), thick-bedded (2-6 ft), crossstratified (wedge-planar type), medium-scale 

grading upward to large-scale; basal part 

pale-red, very sandy and thin-bedded (1-12 

in.); weathers to black face —————————— 34.0

Limestone, pale-red-purple with light-gray, 

irregular blotches, silty; weathers purplishgray, mottled with light-gray; forms weak 

ledge or recess below cliff ——————————— 5.0

Siltstone, pale-reddish-brown; much very fine 

grained sand; platy to medium-bedded; contains many thin lenses of gray, shaly mudstone; forms series of rounded ledges, 

receding ————————————————————— 28.5

forms weak cliffs or bench ——

1Thickness includes channel-fill deposits at base

34.0 Total slope unit, 

Formation ———

Manakacha

93.0
434 THE SUPAI GROUP OF GRAND CANYON

Section 15—Continued 

NATIONAL CANYON-Continued

Feet

—————- 3.0

Supai Group—Continued 

Manakacha Formation, cliff unit:

Limestone, olive-gray with dark-greenishgray, medium-grained, very sandy; contains 

wedge-planar cross-strata; includes redbrown mudstone parting at base; weathers 

to flat, black face with laminae etched on 

surface; forms cliff ——————————————— 12.0

Limestone, medium-light-gray, aphanitic, 

cross-stratified (tabular-planar type); weathers to flat surface, black face ————————— 2.5

Limestone, medium-light-gray, aphanitic, contains many thick, irregular lenses and layers 

of jasper; weathers to rounded purplish

Erosion surface; underlying limestone bed is 

cut out for 100 ft laterally; channel filled 

with red-brown mudstone; channel bottom 

penetrates sandstone below to depth of 2 ft.

Limestone, medium-light-gray, aphanitic (insoluble 15 percent); includes many molds of 

pelloids, probably organic; contains thin 

jasper layers and crosscutting veins; forms 

rounded ledge ————————————

Sandstone, pale-buff, very fine grained, limy, 

silty, thick-bedded (3-6 ft), cross-stratified 

(wedge-planar), medium-scale; forms massive ledge with flat face ——————————

Limestone, olive-gray with dark-greenish-gray, 

aphanitic (insoluble 13 percent); contains 

lenses and thin layers of jasper; includes 

deep-reddish-brown mudstone forming recess at base; forms resistant ledge near base

Siltstone, moderate-reddish-orange, limy, 

thick-bedded; forms double ledge with parting planes of pale-red, shaly mudstone at 

base and in middle; contains thin, flatlaminae; resistant ————————————

Limestone, grayish-pink, sandy, fine- to very 

fine grained, thick-bedded; contains thin 

chert layers, lenses and nodules; weathers to 

resistant ledge with black surface; forms top 

unit in receding series ——————————

Sandstone, moderate-reddish-orange, very fine 

grained (upper half); and moderate-reddishbrown, thin-bedded (0.5-1 ft) siltstone; 

forms slope with crumbly ledges; largely 

concealed

4.0

9.5

13.0

9.0

Section 15—Continued 

NATIONAL CANYON-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Siltstone, grayish-red, calcareous, thinbedded; contains thin layers (0.5-1 in.) of 

jasper in lower part, thick layers above; 

grades upward into pale-yellowish-brown, 

resistant, aphanitic limestone; forms cliff ——

Limestone, moderate-reddish-brown, very fine 

grained, silty, platy; forms slope or receding 

ledges; grades upward into grayish-orangepink, calcareous limestone; contains jasper 

lenses; includes grayish-pink, platy limestone at top ——————————————————

Limestone, grayish-orange-pink, sandy (very 

fine grained), thick-bedded (3 ft), weakly 

cross-stratified (tabular-planar); weathers to 

mottled black and gray surface; forms cliff —

Siltstone, brownish-gray, calcitic dolomite 

matrix, sandy, aphanitic; weathers to rounded black face —-—-—--———————————

Concealed slope —————————————————

Limestone, brownish-gray, fine-grained, thinbedded; contains thin jasper lenses; weathers 

to weak rounded ledge ——————————

Concealed slope —————————————————

Sandstone, moderate-reddish-orange, very fine 

grained, sugary; forms conspicuous marker 

bed; forms rounded ledge at cliff top; bedding surface at base irregular ————————

Sandstone, grayish-orange-pink, very fine 

grained, irregularly bedded; weathers to 

banded white and red-brown cliff; recess of 

crumbly green siltstone at base ——————

Siltstone, pale-red, very sandy, dolomitic, 

medium- to thick-bedded (2-4 ft); contains 

horizontal laminae and cross-laminae, includes scattered gray chert lenses; forms resistctnt ciirr ——————————————————'—-"•————

Feet

8.5

13.0

11.0

1.5 

6.0

6.0 

6.5

1.5

6.0

8.0

27.5

Total cliff unit, Manakacha Formation —————————————160.0 

Total Manakacha Formation —— 253.0

Watahomigi Formation, upper slope unit:

Siltstone, dark-reddish-brown, structureless,

friable; much concealed; forms slope ———— 13.0 

Mudstone, moderate-reddish-brown, structureless; contains scattered, fine quartz 

grains; forms prominent marker bed at base 

of receding ledges; weathers to rounded
MEASURED STRATIGRAPHIC SECTIONS 435

Section 15—Continued 

NATIONAL CANYON-Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit— 

Continued

Siltstone, moderate-reddish-orange to white, 

shaly; grades upward into limy siltstone and 

platy limestone; contains many Rivularites 

impressions; much concealed; forms slope — 

Conglomerate, dark-brown, cross-stratified 

(low-angle) resistant, ledge-forming —————

Matrix: fine- to coarse-grained sand. 

Gravel: jasper, chert, red-brown siltstone 

(rare), quartz, gray limestone; chert subrounded, siltstone and limestone rounded; 

oriented parallel to current bedding; diameter average 0.13-0.5 in. chert; jasper 0.5 

in.; siltstone, limestone 1 in. 

Conglomerate, pebble, pale-reddish-brown, 

friable —————————————————

Matrix: coarse-grained sand and fine gravel. 

Gravel: gray fine-grained limestone (like 

underlying bed); diameter average 1-3 in.; 

rounded to subrounded.

Total upper slope unit, Watahomigi Formation ——————

Watahomigi Formation, middle cliff unit: 

Limestone, pale-yellowish-brown, fine-grained, 

thick-bedded (2-4 ft); contains many thin 

jasper layers (about 80 percent of rock near 

base); weathers to dark-gray, rough surface; 

forms receding ledges or slope ———————

Limestone, medium-light-gray, aphanitic, thinto medium-bedded (2-12 in.), irregularly 

bedded; contains little chert; forms rounded, 

receding ledges or slope ——————————

Mudstone, very dusky red, shaly, crumbly;

rffcTWC JL \JL 11 lj dfin^ DlW L/C _________________ ————————-.-. —__ _-._—_—_ — ______________ _ _

Limestone, medium-light-gray, dolomitic, 

aphanitic; contains much white to brown 

chert in wavy layers (50 percent of rock); 

weathers to gray surface with brown chert 

bands; forms resistant ledge ——————————_ 

Total middle cliff unit, Watahomigi Formation —————— 

Watahomigi Formation, lower slope unit: 

Mudstone, light-brownish-gray, shaly, 

crumbly; contains two ledges of limestone, 

medium-light-gray, medium-grained (lower 

unit bioclastic with silicified Spirifers, 

crinoid joints; upper unit with chert lenses 

and contorted laminae; each limestone unit

Feet

50.5

2.0

3.5

79.0

17.0

14.5

4.0

4.0

39.5

10.5

Section 15—Continued 

NATIONAL CANYON-Continued

Feet

Supai Group—Continued 

Watahomigi Formation, lower slope unit— 

Continued

Limestone, grayish-red, aphanitic; contains 

much chert and jasper, forming lenses and 

crosscutting veins; consists of fine, wavy 

laminae etched on surface; forms upper part 

of cliff ———————————————— 4.0

Limestone, grayish-orange-pink, aphanitic, 

silty; climbing-ripple structure etched on 

face; contains ripple marks on bedding surfaces; thin- to medium-bedded (0.5-12 in.); 

weathers to brown surface with conspicuous 

laminae; forms base of steplike cliff ————— 8.0

Mudstone, dark-reddish-brown, shaly, calcareous; forms slope; upper part much concealed ————————————————— 35.0

Conglomerate, reddish-brown, sandy; forms

thin, resistant ledge —————————————— 1.0 

Matrix: sand, calcitic, granular, friable;

weathers to sandy surface. 

Gravels: chert, red, yellow and a few white; 

hematitic rock, red-brown; subangular to 

subrounded; average diameter 0.25-0.5 

in., maximum 2 in.; contains abundant 

fossils (high-spired gastropods, flat-coiled 

gastropods, Bellerophontids, pelecypods, 

Spirifers, trilobitephygidia).

Conglomerate, reddish-brown with white

gravels, pebbly; forms weak ledges ————— 6.5 

Matrix: brown sand and purplish mud; contains brachiopod molds. 

Gravels: mostly white chert, some red or 

gray; largely angular, some subrounded; 

diameter averages 0.5-2 in., maximum 

12 in.

Mudstone, dark-reddish-brown, silty; forms 

weak slope; mostly concealed ———————— 5.0 

Total lower slope unit, Watahomigi Formation ——————— 70.0 

Total Watahomigi Formation — 188.5 

Total Supai Group ——————— 1,051.0

Unconformity:

Irregular surface with many pits and cracks 

in Redwall to depth of several feet filled with 

grayish-orange-pink conglomeratic sandstone.
436 THE SUPAI GROUP OF GRAND CANYON

Section 15—Continued

NATIONAL CANYON-Continued 

Redwall Limestone: 

Horseshoe Mesa Member: 

Limestone, yellowish-gray, aphanitic, thinto medium-bedded (1-3 ft); includes one 

thick bed (4.5 ft) near top; weathers to gray 

or brown, pitted, rough surface; forms receding ledges.

Section 16 

KANAB CANYON

[On west side of Kanab Canyon, 2 miles north of Colorado River]

Section 16—Continued 

KANAB CANYON-Continued

Feet

Feet

Hermit Shale, slope unit:

Siltstone, bright-red-brown, shaly, slopeforming; contains worm borings, ripple 

marks, impressions of Walchia; surrounds 

and covers rounded hill or mesa of resistant 

siltstone of Esplanade on pre-Hermit erosion 

surface——--——~—————————— 81-110.0

Unconformity:

Erosion surface with relief of 28 ft. 

Supai Group: 

Esplanade Sandstone, main cliff unit:

Sandstone, reddish-brown, massive, cliffforming, lamination absent or weakly developed; upper surface eroded, forms platform 

28 ft high and 400 ft wide ——————————— 44.0

Mudstone(?), deep-reddish-brown, thin, flatbedded; forms prominent bench (Esplanade); 

contains a few thick beds ——————————— 38.5

Sandstone, grayish-pink, very fine grained 

(subrounded), hard, calcareous, massive; 

forms cliff ———————————————————— 85.5

Sandstone, reddish-brown, very fine grained, 

friable, thick-bedded; cross-laminated on 

large-scale; thin, shaly beds at top; weathers 

to slope or recess ———————————————— 26.0

Sandstone, moderate-reddish-orange, mediumto fine-grained (grains frosted, wellrounded), calcareous, hard; alternates with 

pale-reddish-brown to grayish-orange-pink, 

very fine grained (subrounded grains), silty, 

hard, calcareous, massive sandstone; beds 

thick (2-30 ft); contains lenses and thin beds 

of deep-reddish-brown, silty mudrock, 

mostly near base ———————————————— 179.5 

Total main cliff unit, Esplanade

Sandstone ——————————— 375.5

Supai Group—Continued 

Esplanade Sandstone, basal slope unit:

Sandstone, moderate-reddish-brown, very

fine grained, to white (angular, iron-stained),

argillaceous, massive; beds thick (2-6 ft),

cross-laminated ———————————————— 49.5

Total basal slope unit, Esplanade

Sandstone ——————————— 49.5 

Total Esplanade Sandstone ——— 423.0

Wescogame Formation, slope unit:

Sandstone, red-brown, very fine grained, 

sugary, thin-bedded (1-3 ft) ——-—-—-— 22.0 

Total slope unit, Wescogame

Formation ——————————— 22.0

Wescogame Formation, cliff unit:

Sandstone, pale-reddish-brown, calcareous, 

fine-grained and very fine grained (wellrounded, ovoid, bimodal) thick-bedded, 

prominently cross-laminated; weathers to 

black, straight face ——————————————— 12.0

Sandstone, pale-reddish-brown, very fine 

grained (subangular to subrounded, ironcoated), calcareous, cross-laminated; 

weathers to bright-reddish-brown; forms 

rounded cliff; beds 1-4 ft thick —~—-——- 35.0

Sandstone, grayish-orange-pink, fine- to very 

fine grained (subangular), calcareous, crosslaminated; like overlying sandstone but beds 

thick (10-20 ft); massive; weathers brightreddish-brown; deposited on surface of relief 

from pre-Wescogame erosion ——————— 30.0-51.0

Conglomerate, brownish-gray, forms massive 

bed at base of erosion channels ———————— 3.0 

Matrix: reddish-brown siltstone, purple

limestone.

Gravel: gray limestone; rounded; maximum 

diameter 3 in., average 0.5-1 in. ____

Total cliff unit, Wescogame Formation -———————— 80.0-101.0

Total Wescogame Formation —— 123.0

Unconformity:

Erosion surface. 

Manakacha Formation, slope unit:

Sandstone, pink, very fine grained, crosslaminated, sugary; beds 2-6 ft thick; weathers gray; forms cliff; upper surface cut

through by erosion 0-51.5
MEASURED STRATIGRAPHIC SECTIONS 437

Section 16—Continued 

KANAB CANYON-Continued

Supai Group—Continued 

Manakacha Formation, slope unit—Continued

Limestone, brownish-gray, silty, flat-bedded, 

hard; beds 1-3 ft thick; forms slope with receding ledges —————————————————

Total slope unit, Manakacha 

Formation ——————————

Manakacha Formation, cliff unit:

Sandstone, pale-reddish-brown, very fine 

grained (scattered fine grains), subangular, 

calcareous, hard, very massive; crosslaminated on large scale (tabular-planar 

type); weathers gray, silty surface; forms 

cap of cliff in most places ——————•

Sandstone, grayish-pink, very fine grained, 

calcareous, cross-laminated, thick-bedded 

(2-6 ft); weathers to straight face ——————

Siltstone, grayish-orange-pink, sandy, friable, 

calcareous, cross-laminated (festoon-type); 

flat laminae at top; like overlying sandstone, 

but thinner sets (0.5-2 ft); locally shaly; 

forms weak cliff —————————————

Limestone, brownish-gray, aphanitic; contains jasper lenses ————————————

Siltstone or sandstone(?), reddish-brown; 

forms thick sets (2-6 ft); lower part flatbedded, upper part cross-laminated (shallow 

festoon-type); locally shaly ———————

Limestone, reddish-brown, aphanitic; contains jasper lenses ————————————

Siltstone, reddish-brown, forms lenses ————

Limestone, blue-gray, very fine grained, massive; weathers to lavender ledge with silty 

surface; contains reeflike structures of jasper -

Limestone, pale-reddish-purple, silty, crosslaminated, hard; contains jasper bands; 

weathers to lavender, silty surface; forms

Total cliff unit, Manakacha Formation ————————— 

Total Manakacha Formation 

Watahomigi Formation, upper slope unit:

Siltstone, deep-reddish-brown, structureless,

Limestone, pale-reddish-purple, silty, crosslaminated, hard; forms ledge ————————

Siltstone, deep-reddish-brown, structureless, 

slope-forming ————————————————

Limestone, pale-reddish-purple, silty, hard;

feet

18.5

70.0

—- 30.0

22.0

33.0 

5.0

20.0

33.0 

0-2.0

12.0

_3.0

— 160.0

— 230.0

3.0 

5.0 

5.5 

2.0

Section 16—Continued 

KANAB CANYON-Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit— 

Continued 

Siltstone, deep-reddish-brown, structureless,

slope-forming ——————————————-

Limestone, pale-reddish-purple, silty, hard,

ledge-forming; basal portion, reddish-brown

siltstone, with white clayballs ———————

Siltstone, deep-reddish-brown; structureless,

Limestone, pale-reddish-purple; silty, hard; 

forms ledge —————————————————

Feet

- 5.0

8.0

5.5

Limestone, pale-reddish-purple; silty, crosslaminated; forms ledge ———————————

Siltstone, deep-reddish-brown; structureless, 

slope-forming ————————————————

Limestone, pale-reddish-purple; silty, crosslaminated; forms ledge ———————————

Siltstone, deep-reddish-brown; structureless,

Limestone, purple, fine-grained, argillaceous, 

thin-bedded (2-3 in.); contains jasper lenses; 

forms weak ledge ————————————

Siltstone, moderate-reddish-brown; structureless, slope-forming ———————————

Limestone, grayish-red, fine-grained, argillaceous; contains jasper lenses; forms weak 

ledge ————————————————————

Limestone, light-gray, with purple, silty 

blotches; aphanitic; weathers to rounded 

surface; includes purple shale lenses; forms

Limestone, pale-reddish-purple; silty, crosslaminated; forms ledge ———————————

Limestone, light-gray, with purple, silty 

blotches; aphanitic; weathers to rounded 

surface; forms slope ———————————

Limestone, bluish-gray, silty, hard; forms

Concealed -———-——————————————

Limestone, pale-reddish-purple; silty, crosslaminated; forms ledge —————————— 

Conglomeratic limestone, medium-light-gray, 

fine-grained; filled with granules or pelloids 

of dark-gray, rounded limestone; contains 

some jasper; includes red-brown, shaly mudstone at base; forms ledge ———————————_ 

Total upper slope unit, Watahomigi Formation ——————

2.5 

5.5

7.0

4.5

6.5

12.0

3.0

5.5

5.5

6.5 

8.0

4.0

3.0 

4.5

6.0

3.5

121.5
438 THE SUPAI GROUP OF GRAND CANYON

Section 16—Continued 

KANAB CANYON-Continued

Feet

Supai Group—Continued 

Watahomigi Formation, middle cliff unit:

Claystone, pale-reddish-purple, argillaceous, 

calcareous; contains creamy-white blotches 

and deoxidation spots; much concealed; 

forms slope ——————————————————— 13.0

Limestone, pale-reddish-purple, silty; forms 

ledge —————————————————————— 2.5

Limestone, medium-light-gray, with purple, 

silty blotches; aphanitic; weathers to 

rounded surface; forms slope ————————— 6.5

Limestone, grayish-orange-pink, silty, crosslaminated; forms ledge ———————————— 12.0 

Total middle cliff unit, Watahomigi Formation ——————— 34.0

Watahomigi Formation, lower slope unit:

Siltstone, reddish-brown, irregularly-bedded, 

slope-forming; largely concealed; exposed at 

11, 33, and 55 ft above base —————————— 66.0

Limestone, dull-gray, aphanitic, mediumbedded; weathers with pitted surface; forms 

ledge ——————————————————————— 2.5

Siltstone, reddish-brown, irregularly-bedded;

contains limestone fragments; forms slope — 8.5

Limestone, light-olive-gray, aphanitic, mediumbedded; forms ledge —————————————— 3.5

Sandstone, grayish-orange-pink, very fine 

grained, shaly ——————————————— 2.0

Limestone, light-olive-gray, aphanitic; forms

ledge; bedding gnarly and irregular —————— 5.0

Sandstone, pale-reddish-brown to white; finegrained (subrounded) and coarse (wellrounded), silty; includes white quartz, red 

quartz, and flint granules scattered through 

matrix of red, limy silt; bedding gnarly ——— 3.0-5.0 

Total lower slope unit, Watahomigi Formation ——————— 92.5 

Total Watahomigi Formation — 248.0 

Total Supai Group —-————-----1024.0

Unconformity:

Irregular surface with relief as much as 2 ft,

covered with reddish-brown sandstone. 

Redwall Limestone.

Section 17 

S B CANYON

[In S B Canyon (Hundred and Fifty Mile Canyon)]

Feet

Hermit Shale:

Succession of alternating bright-reddish-brown, 

ledge-forming siltstones and dark-reddishbrown, slope-forming mudstones, each 2-12 

ft thick.

Unconformity:

Not recognized at this locality. Contact placed 

where thin-bedded siltstone of Hermit Shale 

rests on highest massive sandstone of Supai.

Supai Group: 

Esplanade sandstone, upper cliff-slope and main

cliff units:

Sandstone, pale-reddish-brown, very fine 

grained (subangular grains); rounded beds; 

medium-bedded (1-4 ft); locally planar 

cross-stratified; upper part white; forms 

prominent cliff ————————————————— 14.0

Siltstone, pale-reddish-brown, very sandy,

shaly, beds 0.25-0.5 in. thick; forms slope — 19.0

Sandstone, moderate-reddish-orange, very 

fine grained, angular, friable, structureless; 

forms receding ledges —————————————— 31.5

Siltstone,pale-reddish-brown, shaly, thinbedded (0.25-0.5 in. thick); forms bench —— 18.5

Sandstone, moderate-reddish-orange, fine- to 

very fine grained, friable; planar crossstratified on medium to large scale; thick sets 

(4-8 ft); forms receding ledges at top of 

gorge ——————————————————————

Sandstone, moderate-reddish-orange, very fine 

grained; cross-stratified on medium to large 

scale (10-60 ft), wedge-planar type; extremely massive; weathers to rounded surface; forms cliff ————————————————— 72.5

Sandstone, grayish-red, very fine grained, 

angular, structureless; contains lightgrayish-green deoxidation spots; weathers 

with conchoidal fracture; forms recess ——— 3.0

Sandstone, pale-red-brown, very fine grained, 

limy (30 percent), thick-bedded (2-5 ft); 

weathers brown; forms cliff with resistant, 

straight face and sharp corners ———————— 19.5

Sandstone, grayish-red, very fine grained 

(angular grains), very muddy, structureless; 

contains light-grayish-green deoxidation 

spots; weathers with conchoidal fractures; 

forms recess ——————————————————— 4.0

22.0
MEASURED STRATIGRAPHIC SECTIONS 439

Section 17—Continued 

S B CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope and

main cliff units—Continued

Sandstone, moderate-orange-pink, very fine 

grained, calcareous (28 percent), thickbedded (3-8 ft), massive; wedge-planar 

cross-stratification locally etched on surface; 

weathers to dark-brown; forms resistant maSandstone, moderate-reddish-orange, very 

calcareous, fine- to very fine grained (includes skeletal fragments), friable; contains 

thin, pinkish-gray streaks; weathers to redbrown; forms irregular ledges (1-3 ft thick) —

Sandstone, grayish-pink, very fine grained; 

contains tabular-planar cross-stratification; 

weathers dark-gray; forms resistant ledge ——

Sandstone, moderate-reddish-orange, very fine 

grained (angular), calcareous (30 percent), 

friable; composed of irregular flat beds; 

weathers red-brown with white streaks; 

forms weak cliff ————————————————

Sandstone, pale-reddish-brown, very fine 

grained; structureless, forms recess —————

Sandstone, moderate-orange-pink, very fine 

grained; weathers to pale-reddish-brown 

with thin, pinkish-gray streaks; forms irregular ledges (1-3 ft thick) within weak cliff -

Sandstone, grayish-orange-pink, very fine 

grained, calcareous, friable; contains series 

of flat-bedded to structureless sets (1-3 ft 

thick) and tabular-planar cross-stratified 

sets, medium-scale (2-8 ft); forms weak cliff -

Sandstone, grayish-orange-pink, very fine 

grained, thick sets (2-6 ft); large-scale (20-30 

ft) tabular-planar cross-stratification (17°

Sandstone, moderate-orange-pink, very fine 

grained (grains angular), calcareous (21 percent); weak cross-stratification, wedgeplanar type, medium- to large-scale (5-40 

ft), includes asymmetric trough-filling and 

wedge-shaped beds; includes some shaly 

siltstone; contains current crescents and cusp 

ripples (0.25-0.5 in. wide); contains Rivularites imprints; weathers white to reddishbrown; honeycombed with solution holes; 

forms massive cliff ———————————————_ 

Total upper cliff-slope and main 

cliff units, Esplanade SandSection 17—Continued 

S B CANYON-Continued

Feet Feet

28.5

13.0

6.0

22.0

2.0

12.0

Supai Group — Continued 

Esplanade Sandstone, basal slope unit:

Siltstone, pale-reddish-brown; contains 

rounded sand grains; thin- , flat-bedded (1-6 

in.); shows brownish-gray streaks (1-2 in. 

thick); films of muddy slime common; worm 

borings, plant stems, mud pellets locally 

common; forms slope —————————————

Sandstone, reddish-brown, very fine grained, 

medium- , flat-bedded (1-3 ft thick); contains irregular white streaks (1-2 in. thick) —

Sandstone, pale-reddish-brown, very fine 

grained, friable; contains irregular, massive 

beds (2-8 ft thick) — — — — —— —— - — — —

Intraformational conglomerate, light-greenishgray to pale-reddish-brown, thickness variable — - — ~————————— — - — — - 2.0-5.0

Matrix: gray, calcareous siltstone.

Pebbles: 0.13-0.5 in. diameter; rounded to

subrounded; widely spaced; maximum

pebbles 4 in. in diameter; composed of

gray to black limestone and red siltstone.

Sandstone, pale-reddish-brown, very fine 

grained (rounded grains), calcareous (25 percent), beds flat, shaly (1.5-2 in. thick); forms

14.5

8.5

35.0

11.0

27.5

38.5

349.0

Conglomerate, pale-reddish-brown, fills depressions, thickness variable ————————— 5.5-7.5 

Matrix: gray, calcareous siltstone. 

Gravels filling depressions: 0.5-2 in. in 

diameter; maximum 5 in.; well-rounded; 

composed of gray to purple limestone. 

Gravels of upper part: 0.13-0.5 in. in diameter; maximum 1 in.; composed of brown, 

sandy limestone and gray to red limestone; also some red siltstone pebbles. ____ 

Total basal slope unit, Esplanade

Sandstone - — - — — — — — — 121.0

Total Esplanade Sandstone ——— 470.0

Erosion surface: Channels as much as 11 ft deep

filled with conglomerate. 

Wescogame Formation, slope unit:

Sandstone, grayish-red, very fine grained, 

dolomitic; grades upward into pale-red, 

dolomitic sandstone, fine-grained; consists 

of lenses and irregular beds (0.5-3 ft thick); 

weathers to a series of red to gray receding

Total slope 

Formation

unit, Wescogame

39.5
440 THE SUPAI GROUP OF GRAND CANYON

Section 17—Continued 

S B CANYON-Continued

Section 17—Continued 

S B CANYON-Continued

Feet

Supai Group—Continued 

Wescogame Formation, cliff unit:

Sandstone, pale-red and pinkish-gray, very 

fine grained, flaggy; contains large-scale 

cross-stratification (40-60 ft; dips 20°-25°); 

contains invertebrate tracks; forms weak 

cliff ____________—___________________—_____________ 35.0

Sandstone, pale-reddish-brown, very fine

grained, crumbly, flat-bedded; forms bench - 12.0

Sandstone, grayish-orange-pink, fine-grained, 

friable, flat-bedded (0.5-2 ft thick); laps 

against dipping beds in channel walls, replacing upper part of underlying sandstone 

cross-strata ——————————————————— 18.5

Total cliff unit, Wescogame Formation ————————————— 65.5 

Total Wescogame Formation —— 105.0

Unconformity:

Channels, 2-6 ft deep, in cross-stratified sandstone filled with flat-bedded sandstone. 

Manakacha Formation, slope unit:

Sandstone, pale-reddish-brown, very fine 

grained, very dolomitic, cross-stratified on 

large-scale; contains invertebrate tracks resembling horseshoe crab trails, on dip-slope, 

extending for 2 ft; forms prominent slope —— 36.0

Sandstone, grayish-orange-pink, very fine 

grained, dolomitic; contains medium-scale 

(10-30 ft), wedge-planar cross-stratification; 

weathers black; forms cap of major cliff ——— 17.5

Sandstone, pale-reddish-brown, very fine 

grained, dolomitic, silty; contains large-scale 

(40-60 ft), planar cross-stratification (beds 

dip 18°-23°); forms major cliff near top of 

member ——————TM————————-—TM—' ori.D

Sandstone, grayish-orange-pink, very fine 

grained, dolomitic; contains medium-scale 

(10-30 ft); planar cross-stratification, thickbedded (3-8 ft thick); weathers black; forms 

resistant ledge ————————————————— 6.0

Sandstone, pale-reddish-brown, very fine

grained, dolomitic, nonstratified; contains

pinkish-gray, spherical sand concretions

scattered throughout; forms weak ledge —— 4.0

Total slope unit, Manakacha

Formation ——————————— 98.0

Sandstone, pale-reddish-brown, very fine 

grained, calcitic-dolomite matrix (42 percent), flat-bedded; contains low-angle, 

medium-scale cross-stratification (10-20 ft); 

bedding sets, 1-3 ft thick; local partings of 

deep-red-brown mudstone at several horizons; white streaks scattered throughout; 

forms series of ledges ———————————

Feet

Supai Group—Continued 

Manakacha Formation, cliff unit:

Sandstone, grayish-orange-pink, very fine 

grained, very dolomitic; contains mediumscale (10-30 ft), planar cross-stratification; 

thick-bedded (3-8 ft); weathers black; forms 

resistant ledge ————————————————— 14.0

Dolostone, pale-reddish-brown, silty, aphanitic 

to very finely crystalline, structureless; contains light-greenish-gray spots (0.25-0.5 in. 

in diameter) scattered throughout; forms

3.0

18.5

Dolostone, calcitic, pale-red-brown, finely 

crystalline, sandy (very fine grains), contains medium-scale cross-stratification (2-5 

ft) of low-angle, compound, channel-fill 

type; weathers grayish-orange-pink; forms 

resistant ledge ————————————————— 6.5

Dolostone, calcitic, brownish-gray, aphanitic; 

contains abundant thin jasper layers scattered throughout; weathers to rough surface; 

forms weak cliff ———————————————— 8.0

Sandstone, grayish-orange-pink, very fine 

grained, very dolomitic; contains large-scale 

(40 ft), wedge-planar cross-stratification 

(tangential base) ———————————————— 10.0

Limestone, brownish-gray, aphanitic, irregularly bedded; contains many jasper lenses 

and thin beds; forms recess —————————— 3.0

Sandstone, grayish-orange-pink, very fine 

grained, dolomitic, platy; thick-bedded (2-8 

ft); tabular-planar cross-stratification, largescale (30-40 ft); grades laterally into sandy 

dolomite; contains thin jasper layers; weathers brown to black; forms weak cliff or slope 19.5
MEASURED STRATIGRAPHIC SECTIONS 441

Section 17—Continued 

S B CANYON-Continued

Feet

Supai Group — Continued

Siltstone, conglomeratic, pale-reddish-brown, 

thin- , flat-bedded (0.25-2 in.); alternating 

with dolomitic (28 percent), white siltstone 

beds; occur as channel-fills in underlying 

siltstone; locally beds dip a few degrees; contain many angular fragments of jasper, dolomite, and mudstone near bases and along 

margins of channels; unsorted, unoriented; 

commonly 1-2 in. in diameter with a maximum of 6 in. —————————————————— 0-24.0 

Erosion surface.

Siltstone, pale-reddish-brown, fine-grained 

(54 percent), limy, massive, thick-bedded 

(10-12 ft); cut by series of channels, some of 

which extend to base; contains irregular 

layers of jasper at various horizons, but 

mostly at top of unit; weathers black; forms

Mudstone, grayish-red-brown, dolomitic; 

forms prominent recess ——————————— 1.0-2.0

Limestone, pale-reddish-brown, finely crystalline, silty, sparkly, resistant, thick-bedded 

(10-12 ft); locally weathers to thinner units 

(0.5-1 ft); grayish-red-brown mudstone

partings locally developed; forms massive 

c]jff

Limestone, grayish-reddish-brown; locally fills 

channels 1-2 ft deep in underlying siltstone —

Siltstone, grayish-pink, sandy, calcareous, 

resistant; contains medium-scale, planar 

cross-stratification; forms prominent cliff ——

Limestone, grayish-red-brown, silty, aphanitic, 

thin-bedded (2-3 ft); weathers lightbrownish-gray; forms resistant ledge —————

Siltstone, grayish-orange-pink, sandy, dolomitic, irregularly bedded; thin-bedded (2-3 

ft); weathers shaly; forms two weak ledges —

Sandstone, pale-reddish-brown, very fine 

grained, dolomitic; locally reddish-gray; 

crumbly; forms slope ——————————————

29 5

3.0

6.5

5.5

8.5

Section 17—Continued 

S B CANYON-Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit:

Mudstone, grayish-red, structureless, brittle; 

locally contains pinkish-gray-brown dolomitic limestone concretions; forms slope ——-

Siltstone, very pale orange, calcareous (26 percent), shaly; weathers to pale-reddishbrown; forms resistant ledge -—-———-——

Mudstone, pale-reddish-brown, silty, calcareous, massive on fresh surface; shaly on 

weathered surface; contains large deoxidation spots; forms weak slope —————————

Concealed, talus covered ——————————

Conglomerate, thick-bedded (2-6 ft); weathers dark-brown to black ————————

Matrix: calcitic dolomite. 

Gravel: 0.25-0.5 in. diameter, some 1 in., 

maximum 2-3 in.; angular to subangular, 

some rounded grains; composed of white, 

yellow, and red chert and jasper, some 

yellow quartz; no orientation of pebbles.

Total upper slope unit, Watahomigi Formation ———————

Watahomigi Formation, middle cliff and lower 

slope units: 

Concealed, talus-covered ————————

Mudstone, pale-reddish-brown, crumbly, 

structureless ————————————————

Concealed, talus covered ——————————

Mudstone-conglomeratic, dark-reddish-brown,

dolomitic, structureless; forms conchoidal

masses; locally contains subrounded pebbles

of dark-gray chert (maximum 6 in.

diameter); forms slope —————————————_

Total middle cliff and lower

slope units, Watahomigi ForFeet

28.5

13.0

16.5

33.0

17.5

108.5

54.0

11.0 

9.0

11.0

85.0

14.0

Sandstone, yellowish-gray, very fine grained, 

dolomitic, thick-bedded (3-4 ft); weathers to 

rounded, pale-reddish-brown surface; forms

___ 

19 fl J-Zi. V

Total cliff unit, Manakacha

Formation ——————————— 187.5 

Total Manakacha Formation —— 285.5

Total Watahomigi Formation — 193.5 

Total Supai Group ————————1054.0

Unconformity:

Surface of relief includes 4-ft channel; solution cracks and bedding planes to 8 ft below 

surface filled with red mud from above. 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, yellowish-gray, aphanitic; thinbedded (0.5-2 ft); pitted surface; forms receding ledges.
442 THE SUPAI GROUP OF GRAND CANYON

Section 18 

TUCKUP CANYON

[Upper part measured in Cottonwood Canyon; lower part in Tuckup

Canyon]

feet

Hermit Shale:

Basal ledge-slope member:

Siltstone, pale-red, shaly, flat-bedded, laminated (0.13-0.25 in.); fills channels in 

underlying unit; forms slope ———————— 3.0

Unconformity:

Small channels (3.0 ft deep) in sandstone of 

Supai filled with shaly siltstone of Hermit. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope and main

cliff units:

Sandstone, grayish-red, very thin bedded 

(1-4 in.); locally platy; locally contains 

cross-stratified wedges; includes many worm 

trails and borings; contains channel fills; 

forms weak ledges ——————————————— 5.5

Siltstone, pale-red, shaly, flat-bedded (0.13-

0.25 in.); forms slope —————————————— 11.0

Sandstone, grayish-red, very fine grained 

(angular grains), laminated (0.25 in.); locally 

platy; elsewhere contains cross-stratified 

wedges; contains worm trails; forms weak 

ledges —————————————————————— 26.5

Sandstone, very pale orange, very fine grained 

(angular grains), friable; forms prominent, 

resistant cap rock ——————————————— 13.0

Sandstone, moderate-reddish-orange, very 

fine grained (subrounded grains); contains 

large-scale, cross-stratification (20-30 ft) of 

wedge-planar type; forms rounded ledge —— 22.0

Sandstone, moderate-reddish-orange, very 

fine grained (subrounded to angular grains), 

flat-bedded, friable; forms wide bench and 

recess —————————————————————————— 2t. u

Sandstone, moderate-reddish-brown, very fine 

grained, (subrounded to angular grains), calcareous, resistant; upper half very pale 

orange; forms prominent ledge ———————— 12.0

Sandstone, pale-reddish-brown, very fine 

grained (rounded grains), thin-bedded (6-24 

in.), flat-bedded; forms receding ledges ——— 11.0

Sandstone, moderate-reddish-orange, very 

fine grained (rounded grains); contains 

large-scale cross-stratification (20-40 ft); 

weathers to massive rounded ledge ————— 20.5

Section 18—Continued 

TUCKUP CANYON-Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope and

main cliff units—Continued

Mudstone, moderate-orange-pink, sandy, 

shaly, laminated (0.13-0.25 in); forms 

bench ——————_____________ 2.0

Sandstone, moderate-reddish-orange, very 

fine grained, limy (40 percent); contains 

medium-scale cross-stratification (2-20 ft) of 

wedge-planar type; forms massive rim ———— 32.0

Siltstone, pale-reddish-brown, flat-bedded; 

forms weak cliff ———————————————— 24.0

Mudstone, pale-reddish-brown, sandy, shaly,

laminated (0.13-0.25 in.); forms bench ——— 5.0

Sandstone, moderate-orange-pink, very fine 

grained, calcareous; contains medium-scale 

cross-stratification (2-20 ft) of wedge-planar 

type; weathers to dark-gray surface; forms 

massive cliff ——————————————————— 14.0

Sandstone, pale-reddish-brown, very fine 

grained, flat-bedded (2-12 in.); forms bench - 7.5

Sandstone, moderate-reddish-orange, very fine 

grained to medium-grained (subangular 

grains), calcareous; very thick sets of strata 

(15-25 ft); each set contains medium-scale 

cross-stratification (2-20 ft) of wedge-planar 

type; weathers to dark-gray surface; forms 

sheer cliff —~————————————— 110.0

Total upper cliff-slope and main 

cliff units, Esplanade Sandstone ————________ 318.0

Esplanade Sandstone, basal slope unit: 

Mudstone, grayish-red; alternating with 

moderate-orange-pink, very fine grained 

(subangular grains), hard, thick-bedded (1-3 

ft) sandstone; forms bench —————————— 23.0 

Sandstone, pale-reddish-brown, very fine 

grained, calcareous (38 percent), resistant; 

contains weakly developed cross-stratification of wedge- and tabular-planar types; also 

contains very pale orange streaks; forms 

resistant ledge ————————————————— 9.5 

Mudstone, grayish-red; includes scattered 

very fine grained sand; alternating with very 

pale orange, very fine grained, thin-bedded 

(1-2 ft) sandstone; forms series of weak 

rounded ledges ————————————————— 9.5
MEASURED STRATIGRAPHIC SECTIONS 443

Section 18—Continued 

TUCKUP CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, basal slope unit— 

Continued

Sandstone, pale-reddish-brown, very fine 

grained, (angular grains), resistant; contains 

three sets of weakly developed cross-stratification of wedge- and tabular-planar types; 

also contains white streaks; forms resistant

Section 18—Continued 

TUCKUP CANYON-Continued

Feet

._ ______ . _ — _____ __ _ ——————— ^1^1. "yy r\u

Sandstone, very pale orange to pale-reddishbrown, very fine grained; locally contains 

small-scale cross-stratification (1-3 ft) with 

low-angle dips; alternating with grayish-red 

mudstone; unit forms series of alternating resistant ledges (3-4 ft) and partings (0.5-1 ft) - 28.0 

Mudstone, grayish-red, brittle; structureless;

forms recess —————————————————— 1.5 

Sandstone, pale-reddish-brown, very fine 

grained, flat-bedded (0.25-1 ft); forms weak, 

rounded ledges ———————————————— 6.5 

Conglomerate, bedding weakly developed; 

irregular basal contact; scattered along bottom of channel 19 ft deep ——————————— 2.0-3.0 

Matrix: red-brown, very fine grained sandstone, calcareous cement. 

Gravel: 0.25-0.5 in. in diameter, maximum 

4 in.; rounded to subrounded; composed 

of gray to blue-gray silty limestone, and 

red and white siltstone. ____ 

Total basal slope unit, Esplanade Sandstone ———————— 103.0 

Total Esplanade Sandstone ——— 241.0

Wescogame Formation, slope unit:

Sandstone, moderate-reddish-orange, very 

fine grained (angular grains), irregular, flatbedded (2-8 ft); contains lenses of grayishred, sandy mudstone at several horizons; 

(forms recess); upper one-third pinkish-gray, 

forms series of receding ledges ———————— 55.0 

Total slope unit, Wescogame 

Formation ——————————— 55.0

Wescogame Formation, cliff unit:

Sandstone, pale-red, calcareous (28 percent), 

very fine grained, silty (23 percent), largely 

massive, thick-bedded (4-6 ft), forms series 

of ledges; alternating with pale-red, silty,

Feet

Supai Group — Continued 

Wescogame Formation, cliff unit — Continued 

Unconformity: buried erosion surface; channel 

23 ft deep, several hundred feet wide, cut into 

underlying sandstone; filled with fine-grained 

sandstone and red-brown siltstone. ____ 

Total cliff unit, Wescogame 

Formation (basal channel sand 

and silt included) ——————— 57.0 

Total Wescogame Formation —— 112.0

Manakacha Formation, slope unit:

Sandstone, moderate-orange-pink, very fine 

grained (angular grains), calcareous; contains wedge-planar cross-stratification (2-20 

ft); weathers with abundant solution holes; 

forms prominent cliff —————————————

Sandstone, pale-red, very fine grained (angular grains), calcareous; contains medium- to 

large-scale cross-stratification (5-30 ft); 

mostly tabular-planar type with some 

wedge-planar; cosets of cross-stratification 

very thick (3-20 ft); contains layer with 

spherical stromatolites (8-12 in. diameter) 

covering surface for 30 ft; forms very re49.5

thick-bedded (1-3 ft), mudstone 57.0

Mudstone, grayish-red, brittle; structureless;

forms recess —————————————————— 1.0 

Siltstone, pale-reddish-brown; forms weak

Sandstone, pale-reddish-brown, very fine 

grained, muddy, brittle; structureless; forms

r*os**occ _ _ _«_«___.•____«___...»___«___ "I II 1CV.C33 — ————————————————— -L.w

Conglomerate, brown sandy ledge ——————— 0-1.0 

Matrix: sandstone, brown; cement calcareous.

Gravel: mostly white chert; 0.13-0.5 in. in 

diameter, maximum 8 in.; angular fragments. ____ 

Total slope unit, Manakacha

Formation ——————————— 83.5

Manakacha Formation, cliff unit: 

Limestone, dolomitic, pale-red, silty, thickbedded (2-4 ft), flat-bedded; forms part of

major cliff ———————————————————— 21.0 

Limestone, olive-gray, aphanitic; contains

irregular thin layers and lenses of jasper;

forms cliff — — — — ——— ~ ——— - —— - ——— 11 . 0
444 THE SUPAI GROUP OF GRAND CANYON

Section 18—Continued 

TUCKUP CANYON-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Limestone, light-brownish-gray, finely crystalline, sandy; contains planar cross-stratification conspicuously etched on surface ———

Limestone, light-olive-gray, aphanitic; contains irregular, thin layers and lenses of 

jasper; forms basal cliff —————————

Siltstone, pale-reddish-brown; many scattered 

fine- to very fine grained quartz particles; 

brittle, very thin bedded (0.5-1 ft); contains 

partings of brittle, structureless grayish-red 

mudstone; forms slope ——————————

Limestone, light-brownish-gray, finely crystalline, resistant, silty; contains grayish-red 

mudstone partings and thin jasper layers; 

forms series of ledges —————————

Limestone, pale-red, muddy, silty; very thin 

bedded (1-3 in.); contains some jasper nodules; forms rounded ledge —————————

Sandstone, pale-reddish-purple, very fine 

grained (angular grains), calcareous; contains thin jasper layers; weathers black;

Sandstone, pale-reddish-brown, very fine 

grained, muddy, weakly bedded; forms

Sandstone, light-brownish-gray, dolomitic; 

contains planar cross-stratification; laminae 

etched on black weathered surface; forms resistant ledge ————————————————

Total cliff unit, Manakacha ForTotal Manakacha Formation —— 

Watahomigi Formation, upper slope unit: 

Limestone, light-brownish-gray, silty, very 

thin bedded (1-3 in.); contains concretions; 

weathers black; forms rounded ledge ———— 

Siltstone, pale-reddish-brown, shaly, irregularly bedded; contains limestone nodules;

rj"\i*mc cl/"\rxi ———_————__________._«.«..«_«.«——_—————_——_——_ 1U11115 5HJ^/C

Dolostone, calcitic, light-brownish-gray, silty, 

contains thin jasper layers; weathers to black 

face; forms resistant ledge —————————

Siltstone, pale-reddish-brown, muddy, 

crumbly; largely concealed; locally exposed; 

forms slope —————————————————

Conglomerate, gray; contains Orbiculoidea 

and other fossils; weathers to rounded ledge -

Feet Feet

6.0

5.5

5.0

- 38.0

5.5

15.0 

5.0

_8.5

120.5

204.0

8.5 

10.0 

3.0

55.0 

3.0

Section 18—Continued 

TUCKUP CANYON-Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit— 

Continued

Conglomerate—Continued 

Matrix: brown siltstone. 

Cement: siliceous.

Gravel: greenish-gray and orange chert, 

jasper, mudstone; 0.25-0.5 in. in diameter; maximum diameter 2 in.; angular to 

subangular. ____ 

Total upper slope unit, Watahomigi Formation ——————— 79.5

Watahomigi Formation, middle cliff unit:

Claystone, pale-reddish-purple, brittle; contains white limestone concretions; forms

Dolostone, calcitic, to limestone (25 percent 

insoluble) yellowish-gray, with thin beds of 

pale-red limestone; aphanitic; thick-bedded 

(2-4 ft); contains grayish-red mudstone parting beds (1-2 in.) and irregular layers of 

jasper and white chert at various horizons; 

forms series of ledges or a weak cliff ————— 53.5 

Total middle cliff unit, Watahomigi Formation ——————— 59.5 

Watahomigi Formation, lower slope unit:

Siltstone, pale-reddish-brown, muddy, calcareous, shaly (0.13-0.15 in.); forms slope — 18.5

Mudstone, pale-reddish-brown, brittle, 

crumbly; conglomeratic; contains Spirifer, 

Spiriferina, and productid brachiopods; 

forms slope ——————————————————— 15.0

Conglomerate, grayish-red; forms weak ledge — 3.0 

Matrix: grayish-red mudstone. 

Gravel: white chert fragments; average 

0.15-1 in. in diameter, maximum 3 in.;

angular. ———— 

Total lower slope unit, Watahomigi Formation ——————— 36.5 

Total Watahomigi Formation — 175.5 

Total Supai Group ———————— 912.5

Unconformity:

Channel-cut erosion surface. 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, light-olive-gray, aphanitic; thinbedded (6-24 in.); weathers to rough surface; forms receding ledges.
MEASURED STRATIGRAPHIC SECTIONS 445

Section 19 

BLUE MOUNTAIN CANYON

[In Blue Mountain Canyon, southwest side, T. 26 N., R. 9 W.; upper part 

measured on west side of Tower of Babylon]

Section 19—Continued 

BLUE MOUNTAIN CANYON-Continued

feet

Hermit Shale:

Mudstone, pale-reddish-brown, shaly; forms 

bench and slope —————————————

feet

9.0

Contact:

Surface even; no evidence of erosion detected 

at this locality.

Supai Group: 

Esplanade Sandstone, main cliff unit:

Sandstone, moderate-orange-pink, very fine 

grained, some fine-grained (15 percent), very 

limy (48 percent), friable; contains mediumscale, tabular-planar cross-stratification 

(1-4 ft), and some flat beds with Rivularites 

impressions and worm trails, at 50 ft up; 

forms rounded blocks and receding ledges — 76.0

Limestone, pale-red and light-gray, fine- to 

medium-grained, very sandy (30 percent), 

rounded quartz, rounded pelloids in sparry 

calcite; medium- to thick-bedded (2-4 ft); 

forms prominent ledge ———————————— 6.5

Concealed slope, locally medium-bedded,

crumbly siltstone exposed ——————————— 16.0

Sandstone, moderate-reddish-orange, very fine 

grained, resistant; limy (35 percent); weakly 

cross-stratified on medium to large scale; 

contains thin mudstone partings throughout; 

forms series of receding, massive, rounded 

ledges —————————————————————— 28.0

Limestone, pale-red; fine-grained; very sandy; 

cross-stratified on medium scale, tabularplanar units 1-3 ft thick; middle part grades 

into pale-red, silty sandstone (60 percent insoluble) and forms bench; weathers with 

conspicuous brown laminae etched on gray 

surface ————————————————————— 35.0

Siltstone, pale-red-brown, very limy (49 percent); weathers to rounded massive beds 

(1-2 ft); forms part of cliff series ——————— 7.0

Concealed slope ————————————————— 5.5

Sandstone, pale-reddish-brown, very fine 

grained; limy (25 percent), very resistant, 

medium-bedded (2-3 ft), flat-bedded; forms 

rounded ledge —•———————————— 25.0

Supai Group—Continued

Esplanade Sandstone, main cliff unit—Continued 

Sandstone, moderate-reddish-orange, very fine 

grained, limy (33 percent); massive (units 

5-10 ft thick), calcareous; contains planar 

cross-stratification on large scale; forms bottom of prominent cliff ————————————— 22.0 

Total main cliff unit, Esplanade

Sandstone ——————————— 221.0

Esplanade Sandstone, basal slope unit:

Siltstone, pale-reddish-brown, shaly, limy, 

muddy, grains iron-oxide coated; contains 

abundant lenses and irregular layers of palebrown siltstone; abundant worm tubes and 

Rivularites sp. impressions; forms slope ——— 11.5

Concealed slope ————————————————— 16.5

Siltstone, medium-light-gray and moderateorange-pink, very sandy, limy, thin-bedded 

(1-6 in.); irregular, nodular structure; and 

light- to dark-gray, rubbly, nodular limestone; forms bench —————————————— 5.5

Sandstone, moderate-orange-pink, very fine 

grained (88 percent), friable; limy (25 percent); contains cross-stratification, mediumscale; forms upper part of ledge ——————— 6.5

Sandstone, pale-reddish-brown, very fine 

grained, muddy, medium-bedded (1-2 ft); 

contains white deoxidation spots; forms bottom half of ledge ——————————————— 3.0 

Concealed slope; probably thin-bedded siltSandstone, pale-reddish-brown, very fine

grained, limy, structureless; forms ledge —— 3.0 

Limestone, moderate-orange-pink, very silty 

(45 percent), thin- , flat-bedded (0.5-1 in.), 

friable; forms slope —————————————— 5.5

Conglomerate, pebbly, with scattered fragments of reddish-brown mudstone, brown 

siltstone and gray limestone, as much as 0.5 

in. in diameter; and pale-reddish-brown, 

aphanitic, silty (33 percent), flat-bedded, 

medium-bedded (1-2 ft) limestone; forms 

ledge ——————————————————————— 3.5

Total basal slope unit, Esplanade Sandstone ———————___ 

Total Esplanade Sandstone ——— 288.0

67.0
446 THE SUPAI GROUP OF GRAND CANYON

Section 19—Continued 

BLUE MOUNTAIN CANYON-Continued

Supai Group—Continued 

Wescogame Formation, slope unit:

Sandstone, grayish-pink, very fine grained, 

slightly calcareous; contains planar crossstratification, medium- to large-scale; 

weathers reddish-brown and gray; forms 

massive, rounded, receding ledges —————— 

Conglomerate-limestone, medium-light-gray 

with pebbles of pale-reddish-brown chert; 

forms cap to cliff ————————————————_ 

Total slope unit, Wescogame 

Formation ———————————

Feet

23.0

2.0

25.0

Wescogame Formation, cliff unit:

Limestone, sandy (35 percent); grades upward 

into grayish-pink and moderate-orangepink, very fine grained, friable, very limy 

(49 percent) sandstone; cross-stratified, 

medium- to large-scale wedge-planar type; 

forms major cliff ———————————————— 77.0 

Total cliff unit, Wescogame Formation ————————————— 77.0 

Total Wescogame Formation —— 102.0

Manakacha Formation, slope unit:

Siltstone, pale-reddish-brown, resistant; contains planar cross-stratification with wavy, 

irregular laminae; contains jasper lenses and 

layers (0.5-2 in. thick); forms series of resistant ledges (2-4 ft) ————————————— 11.0

Concealed slope ————————————————— 4.5

Limestone, pale-reddish-brown, very fine 

grained, silty (30 percent), resistant; contains scattered concretions of jasper; weathers to resistant, black face with irregular 

laminae etched on surface ——————————— 10.0

Limestone, medium-gray, aphanitic, thinbedded (4-8 in.); contains white chert bands; 

forms steep slope or ledge; partly concealed — 11.0

Limestone, light-brownish-gray, aphanitic, 

silty (25 percent), resistant; contains crosslamination, medium-scale, locally wavy and 

irregular; contains chert and jasper in lenses 

and rounded nodules; weathers black; forms 

vertical cliff ——————————————————— 16.5

Concealed slope, locally pale-reddish-brown, 

blocky, silty mudstone ———————————— 13.0 

Total slope unit, Manakacha

Formation ——————————— 66.0

Section 19—Continued 

BLUE MOUNTAIN CANYON-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit:

Limestone, pale-reddish-brown, aphanitic; 

abundant jasper lenses; forms cliff ——————

Siltstone, bright-reddish-brown, crumbly, 

irregularly bedded; forms weak ledge or 

siopc —————————————————————————————**———

Limestone, dull-gray; contains abundant, irregular layers of jasper and white chert 

forming conspicuous reticulate pattern on 

face; forms resistant cliff ———————————

Sandstone, moderate-reddish-orange, very 

fine grained, limy, crumbly, irregularly bedded; forms slope ————————————————

Limestone, light-brownish-gray; aphanitic; 

contains abundant irregular layers of jasper 

and white chert forming conspicuous 

reticulate pattern on face; forms resistant 

cliff at bottom of series ————————————

Concealed slope ————————————————— 

Siltstone, pale-reddish-brown, very limy (48 

percent), aphanitic to very fine grained; irregularly laminated; contains some jasper; 

forms resistant ledge ——————————————

Concealed slope ————————————————— 

Siltstone, pale-reddish-brown, limy (35 percent magnesian Is.); forms resistant ledge —— 

Siltstone, pale-reddish-brown, limy (35 percent), structureless; forms partly concealed

Siltstone, light-brownish-gray, aphanitic, very 

limy (47 percent); forms irregular rounded

Concealed slope —————————————————

Siltstone, pale-reddish-brown, thick-bedded 

(4 ft); forms resistant cap to cliff ———————

Siltstone, light-brownish-gray, very limy (47 

percent); contains irregular, purple laminae; 

includes lenses of jasper and dark-gray chert; 

forms lower half of prominent ledge —————

Siltstone, light-brownish-gray with pale-red 

streaks; contains 35 percent very fine grained 

sand; resistant, thick-bedded (2-3 ft); forms 

rounded ledges —————————————————

Limestone, pale-reddish-brown, silty (20 percent), aphanitic; forms resistant ledge ————

Feet

7.0

5.5

5.0

5.5

8.0 

13.0

3.0 

15.5

2.0 

5.5

5.5 

4.0

4.0 

5.0

7.5 

2.5
MEASURED STRATIGRAPHIC SECTIONS 447

Section 19—Continued 

BLUE MOUNTAIN CANYON-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Concealed slope; few beds of purple-gray and 

pale-reddish-brown, flat-bedded (1-2 ft) 

muddy siltstone, locally exposed —————— 

Siltstone, reddish-brown, calcareous, mediumbedded; contains several jasper beds (2-3 in. 

thick); forms ledge ————————————

Concealed slope ———————————————

Siltstone, pale-reddish-brown, muddy, calcareous, medium-bedded; contains several 

jasper layers (2-3 in. thick); forms ledge —— 

Limestone, pale-reddish-brown; shaly, very 

silty (46 percent); forms slope ——————

Concealed slope —————————————

Limestone, light-brownish-gray, aphanitic to

very fine grained, very silty (insoluble 33

percent), thick-bedded (4 ft); contains thin,

irregular jasper layers; forms resistant ledge —

Concealed slope ———————————————

Limestone, light-brownish-gray at base, very 

fine grained; medium-light-gray above; 

aphanitic with fine grains locally concentrated; medium-bedded (2-3 ft); contains irregular and crosscutting layers of jasper; 

forms resistant cliff ————————————

Total

Section 19—Continued 

BLUE MOUNTAIN CANYON-Continued

Feet Feet

31.0

1.5 

5.5

4.0

2.0 

19.0

8.5 

9.0

22.0

cliff unit, Manakacha 

Formation ——————————— 201.0 

Total Manakacha Formation —— 267.0

Watahomigi Formation:

Concealed slope ————————————————— 67.0

Mudstone, pale-reddish-brown, brittle; forms

slope —————————————————————— 13.0

Siltstone, pale-reddish-brown, flat-bedded, 

thin- to medium-bedded (2-12 in.); forms 

weak ledge ——————————————————— 2.5

Mudstone, grayish-red and moderate-orangepink layers; brittle, crumbly; and grayishred, shaly, thin-bedded siltstone; total forms 

slope ——————————————————————— 22.0

Limestone, light-brownish-gray, medium- to 

very coarse grained, crinoidal; forms resistant ledge —————————————————— 24.0

Concealed slope ————————————————— 16.5

Limestone, very light gray, aphanitic; weathers to rough surface; forms rounded ledge — 8.0

Supai Group—Continued 

Watahomigi Formation—Continued

Concealed slope; probably red-brown mudstone ——————————————————————— 15.5 

Conglomerate, grayish-orange; contains thick,

irregular bedding; massive; forms ledge ——— 5.5 

Matrix: coarse sandstone. 

Gravel: scattered pebbles of gray to white 

chert, subangular to angular (maximum 

diameter 2 in.); weathers yellow-brown. ____ 

Total Watahomigi Formation — 174.0 

Total Supai Group ———————— 831.0

Contact:

Unconformity not apparent locally. 

Redwall Limestone:

Horseshoe Mesa Member: 

Limestone, light-brownish-gray, fine- to very 

fine grained, thin-bedded (4-12 in.).

Section 20 

PROSPECT VALLEY

[On east side of Prospect Valley, 6 miles south of Colorado River]

Feet

Hermit Shale:

Mudstone, red-brown, shaly; includes weak 

ledge of thin- , flat-bedded siltstone in middle; forms slope ————————————————— 26.5 

Contact:

Flat, shaly beds of Hermit rest on resistant 

sandstone of Supai with no noticeable surface of relief. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope and main

cliff units:

Siltstone, moderate-reddish-orange, calcareous, hard; weakly cross-stratified on medium scale; forms rounded ledges (3-5 ft thick) 16.5

Concealed slope ————————————————— 10.0

Sandstone, moderate-reddish-orange, fine- to 

very fine grained; calcareous, cross-stratified 

on medium-scale (sets 1-3 ft thick), tabularplanar; includes some thin (1-12 in.), 

horizontal beds; contains a thick (10 ft) 

tabular-planar bed; total forms receding, 

rounded ledges ———————————————— 45.0
448 THE SUPAI GROUP OF GRAND CANYON

Section 20—Continued 

PROSPECT VALLEY-Continued

Section 20—Continued 

PROSPECT VALLEY-Continued

Feet Feet

Supai Group—Continued

Esplanade Sandstone, upper cliff slope and 

main cliff units—Continued 

Sandstone, moderate-reddish-brown, silty; 

calcareous, friable; beds medium (0.5-1 ft 

thick); structureless; forms recess or slope — 5.5

Siltstone, reddish-brown, shaly, flat-bedded;

forms wide bench ———————————————— 10.0

Sandstone, moderate-orange-pink, fine- to 

very fine grained, calcareous; contains series 

of massive, cross-stratified units (each 15-20 

ft thick); cross-strata mostly wedge-planar 

type, 1-3 ft thick; total forms single, resistant cliff ———__________———- 126.5 

Total upper cliff-slope and main 

cliff units, Esplanade Sandstone —————————————— 213.5

Esplanade Sandstone, basal slope unit: 

Mudstone, pale-reddish-brown, calcareous, 

medium-bedded (1-2 ft thick), moderately 

resistant; alternating with pale-reddishbrown, calcareous, shaly, medium-bedded 

(1-3 ft thick) siltstone; unit forms base of 

cliff or recess under Esplanade cliff ————— 8.5

Concealed slope; mudstone locally exposed —— 16.0

Siltstone, moderate-orange-pink and moderatereddish-brown; slightly calcareous, mediumto thick-bedded, structureless; contains liesegang bands in many places; weathers palereddish-brown; forms well-rounded, receding ledges ———————————————————— 20.5

Sandstone, pale-reddish-brown, very limy, 

thick-bedded (3-8 ft), weakly crosslaminated locally, resistant; commonly 

develops black varnish on face; forms small

rljff _______________________________ 1 c c \_1111 TM» A.+J **s

Limestone, pale-reddish-brown, very silty, 

flat-bedded; contains gray concretionary 

structures; forms slope or rounded ledges —— 22.0

Sandstone, pale-reddish-brown, calcareous, 

silty, very friable, very fine grained, thinbedded, flat-bedded; contains low-angle 

cross-beds (cosets 6-24 in. thick); contains 

small conglomerate lenses 5 ft above base; 

forms slope with weak ledges ————————— 22.0

Supai Group—Continued 

Esplanade Sandstone, basal slope unit— 

Continued

Conglomerate, gray to reddish-brown; forms 

resistant ledge with great lateral variation in 

thickness ———————————————————— 1.0-7.0 

Matrix: siltstone, gray to reddish-brown. 

Pebbles: Composition—reddish-brown siltstone, light-gray limestone, dark-gray 

limestone; Size—mostly 0.25-1 in. in 

diameter, maximum 3 in.; Roundness— 

mostly subangular but many wellrounded. ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 111.5 

Total Esplanade Sandstone ——— 325.0

Wescogame Formation, slope unit:

Sandstone, grayish-orange-pink, very fine 

grained, silty, calcareous, friable; weakly 

cross-stratified in thick cosets (2-4 ft); upper 

part more resistant and structures more 

prominent than below; forms resistant 

ledges or rounded cliff ———————————— 27.5

Limestone, moderate-reddish-orange, very 

silty with some very fine grained sand, calcareous, structureless; forms rounded ledge 

or part of cliff —————————————————— 6.5

Sandstone, moderate-orange-pink, fine- to 

very fine grained, calcareous; prominently 

cross-stratified (tabular- and wedge-planar); 

cosets 2-4 ft thick; weathers to resistant 

ledge with brown varnish on face —————— 14.0 

Total slope unit, Wescogame

Formation ——————————— 48.0

Wescogame Formation, cliff unit:

Siltstone, pale-reddish-brown, calcareous, 

friable; contains some very fine grains; 

cross-stratified on medium scale (10-20 ft); 

contains many white deoxidation spots; 

forms bench or recess ————————————— 7.5

Siltstone, pale-reddish-brown, calcareous; 

contains some very fine grains; flat-bedded, 

shaly to medium-bedded (0.5-12 in. thick); 

forms receding ledges and weak benches —— 16.5

Limestone, pale-reddish-brown, silty, fine- to 

very fine grained; conspicuously crossstratified (trough-type structure) locally; 

weathers to reddish-brown, silty surface; 

forms receding ledges (2-4 ft thick) ————— 6.5
MEASURED STRATIGRAPHIC SECTIONS 449

Section 20—Continued 

PROSPECT VALLEY-Continued

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued

Sandstone, pale-reddish-brown, very fine 

grained, calcareous, cross-stratified (lowangle, large-scale); weathers reddish-brown; 

forms resistant ledge ———————————

Limestone, pale-reddish-brown near base, 

light-brownish gray above, very silty at bottom, less silt above; very fine grained, upper 

part prominently cross-stratified (troughtype); medium- to thick-bedded (2-4 ft); 

forms receding rounded ledges ——————

Concealed slope; probably shaly siltstone ———

Siltstone, pale-reddish-brown, calcareous, 

structureless; contains some very fine 

grained sand; forms resistant ledge —————

Concealed slope, locally exposed, palereddish-brown, slightly calcareous, shaly 

siltstone, like that below —————————

Sandstone, pale-reddish-brown, very fine 

grained, slightly calcareous; forms resistant

Siltstone, pale-reddish-brown, slightly calcareous, shaly to thin-bedded (0.25-0.5 in.); 

contains shrinkage cracks and algal forms, 

cf. Rivularites; forms weak ledge —————— 

Concealed slope —————————————————_ 

Total cliff unit, Wescogame Formation —————————————_ 

Total Wescogame Formation —— 

Manakacha Formation, slope unit: Absent. 

Manakacha Formation, cliff unit:

Sandstone, moderate-orange-pink, very fine 

grained, silty; slightly calcareous, crossstratified (tabular- and wedge-planar); cosets 

of medium scale (1-3 ft thick); near top it is 

thicker bedded, calcareous, very fine 

grained, more massive, grayish-pink, 

weathers to rounded surface with many 

solution pits; forms resistant cliff —————— 

Siltstone, creamy-white; contains some very 

fine grained sand; calcareous, friable; 

medium-bedded (1-3 ft thick); weathers 

pale-gray, locally with brown reticulate pattern of siliceous material; forms rounded

Total exposed cliff unit, Manakacha Formation ———————_ 

Total Manakacha Formation —— 

Concealed by talus.

Feet

Section 21 a 

TOROWEAP VALLEY

[Measured south of Toroweap Point, east of lava flows]

4.0

12.0 

4.0

2.5

12.0

2.0

2.5 

5.5

75.0

123.0

34.5

5.5

Feet

40.0 +

40.0 +

Hermit Shale:

Ledge-slope unit:

Siltstone, pale-reddish-brown, shaly, forms

Unconformity:

Top of Supai (sandstone, moderate-orangepink, cross-stratified) bevelled to nearly flat, 

slightly undulating surface with relief as 

much as 4 ft in 0.25 mi; shaly to mediumbedded siltstone rests on erosion surface and 

overlaps small hills.

Supai Group: 

Esplanade Sandstone, upper cliff-slope unit:

Sandstone, moderate-reddish-orange, very 

fine grained (angular grains); includes finegrained sand (20 percent) near top; calcareous, resistant, thick-bedded (3-8 ft); locally 

cross-stratified (medium-scale, tabularplanar); includes shaly, muddy partings, 

sand (37 percent), pale-reddish-brown (2-12 

in.) and lens of bright red-brown, shaly 

mudstone, 4 ft thick, pinching out in 600 ft, 

weathers gray to light-red-brown; forms 

massive cliff ——————————————————— 52.5

Mudstone, pale-reddish-brown, calcareous,

silty, shaly; forms slope ———————————— 5.5

Siltstone, moderate-reddish-orange, very fine 

grained sand (41 percent), calcareous (20 

percent), friable; weathers to weak, rounded 

ledge or slope ————————————————— 11.0

Mudstone, pale-reddish-brown, calcareous (43 

percent), shaly; contains sand (9 percent); 

forms slope ——————————————————— 13.0

Sandstone, moderate-orange-pink, very fine 

grained, friable; weathers to weak, rounded 

ledge or slope ————————————————— 22.0

Siltstone, pale-reddish-brown, muddy, shaly, 

gypsiferous (35 percent); forms slope ———— 9.0

Sandstone, moderate-orange-pink, very fine 

grained (angular grains), very gypsiferous 

(48 percent); forms weak ledges ——————— 13.0 

Total upper cliff-slope unit, Esplanade Sandstone —————— 126.0
450 THE SUPAI GROUP OF GRAND CANYON

Section 21a (east side)—Continued 

TOROWEAP VALLEY-Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, main cliff unit:

Sandstone, moderate-reddish-brown, finegrained (38 percent); contains very fine 

grained quartz; clay matrix (22 percent); 

limy (45 percent); thick-bedded (2-12 ft); 

locally massive to cross-stratified (mediumto large-scale); contains scattered grains of 

well-rounded, frosted, medium-size quartz; 

forms receding cliff —————————————— 49.5 

Sandstone, yellowish-white to pale-red, calcareous; cross-laminated on large scale; 

weathers same with black varnish; forms 

massive cliff ——————————————————— 105.5 

Sandstone, dark-reddish-brown, very fine 

grained; weathers same; forms massive cliff 

with rounded surfaces ————————————— 21.0 

Total main cliff unit, Esplanade

Sandstone ——————————— 176.0

Esplanade Sandstone, basal slope unit:

Mudstone, pale-reddish-brown, silty, calcareous, beds thin (2-6 in.) and flat; forms slope - 8.5

Sandstone, pale-reddish-brown to moderatereddish-orange; very fine grained, friable, 

silty (30 percent), mostly flat-bedded, locally 

cross-stratified on small scale; forms series of 

weak ledges —————————————————— 23.0

Concealed, talus slope —————————————— 5.0

Sandstone, moderate-reddish-orange, very fine 

grained, silty (30 percent), friable, thinbedded (1 ft); forms rounded ledge ————— 3.0

Siltstone, pale-reddish-brown, contains scattered very fine grained sand, thin-bedded 

(2-12 in.); irregular beds; forms ledge ———— 7.5

Conglomerate, moderate-reddish-brown with 

scattered light-gray pebbles throughout; fills 

channels 1-2 ft deep and 6-10 ft wide ———— 1.0-2.0 

Gravel: light-gray siltstone, deep-reddishbrown mudstone; maximum diameter 2 

in., average diameter 0.25-0.5 in.; wellrounded.

Matrix: very fine grained quartz sand and 

reddish-brown mud.

Sandstone, pale-reddish-brown, platy, very 

fine grained, and sandstone, grayish-orangepink, very fine grained, friable, thin-bedded; 

form weak ledges and slope —————————— 8.5

Section 21a (east side)—Continued 

TOROWEAP VALLEY-Continued

Supai Group—Continued

Esplanade Sandstone, basal slope unit— 

Continued

Sandstone, moderate-reddish-brown, very 

fine grained, flat-bedded; and pale-reddishpurple, very fine grained, laminated sandstone; form rounded ledges and weak cliffs — 

Sandstone, yellowish-white, calcareous; crossstratified on large scale; includes local sandstone conglomerate; forms massive ledge —— 

Conglomerate, light-brownish-gray, thinbedded (2-12 in.); weathers to rough surface; forms weak ledge ———————————— 

Gravel: reddish-brown siltstone, greenishgray limestone, rare red jasper; maximum 

diameter 2 in., average diameter 0.5-1 in.; 

rounded to subrounded. 

Matrix: poorly sorted sand.

Total basal slope unit, Esplanade 

Sandstone ——————————— 

Total Esplanade Sandstone — 

Wescogame Formation, slope unit:

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous (33 percent); crossstratified on large scale; weathers palereddish-brown; pitted in many places ———— 

Sandstone, pale-reddish-purple, very fine 

grained, silty (24 percent); beds thin and flat 

(0.5-12 in.); forms slope ———————————— 

Total slope unit, Wescogame 

Formation ——————————— 

Wescogame Formation, cliff unit:

Limestone, light-brown, very sandy, massive — 

Limestone, pale-reddish-brown, sandy, crossstratified; weathers moderate-brown; forms

Sandstone, moderate-reddish-orange, very 

fine grained, cross-stratified on large scale; 

forms weak cliff ————————————————

Limestone, grayish-orange-pink, sandy, crossstratified; weathers moderate-brown; forms

Limestone, light-brownish-gray and moderateorange-pink, aphanitic, hard; forms ledge —

Limestone, grayish-orange-pink, sandy, crossstratified; contains fusulinids (chapter E, p. 

85); weathers moderate-brown; forms ledge -

Sandstone, moderate-reddish-orange, very 

fine grained, friable, structureless; grains 

iron-stained; forms slope ———————————

Feet

52.0

11.0

9.5

- 130.0

- 432.0

44.0

27.5

71.5 

2.5

8.5

27.5

6.0

7.5

6.0 

21.0
MEASURED STRATIGRAPHIC SECTIONS 451

Section 21a (east side)—Continued 

TOROWEAP VALLEY-Continued

Feet

Supai Group—Continued 

Wescome Formation, cliff unit—Continued 

Sandstone, pale-reddish-brown; channel deposits; contains much very fine grained 

sand, silty (30 percent); calcareous, resistant; beds 1-4 ft thick; weakly crossstratified; forms weak cliff —————————— 12.0 

Conglomerate, gray- to brown-ledge; fills 

narrow channels and covers irregular surface 

of crossbedded, sandy limestone ————— 1.0-11.0 

Matrix: gray, limy sandstone and sandy

limestone.

Gravel: white chert, reddish-brown siltstone, light-gray limestone, pink limestone, dark, silty limestone (no jasper 

noted); Size—maximum diameter 9 in.; 

commonly 6-8 in.; mostly 0.5-2 in.; wellrounded; shape elongated, mostly platy; 

Orientation—long axis mostly horizontal. ____ 

Total cliff unit, Wescogame Formation —————————————102.0 

Total Wescogame Formation —— 173.5

Manakacha Formation, slope unit: Absent. 

Manakacha Formation, cliff unit:

Limestone, pale-reddish-purple, sandy, crosslaminated; weathers moderate-brown; forms 

ledge _______________________ 13 0

Limestone, medium-light-gray, aphanitic, 

ledge-forming ————————————————— 7.5

Limestone, grayish-pink, sandy, cross-laminated; contains detrital fusulinids; weathers 

with moderate-brown laminae on gray surface; forms ledge ———————————————— 10.0

Limestone, gray, aphanitic, ledge-forming; 

contains bands of red jasper ————————— 5.0

Siltstone, grayish-red-brown, silty, calcareous, 

friable; contains limestone concretions ——— 2.0

Limestone, pale-reddish-brown, fine-grained; 

contains jasper; weathers pale-reddishbrown; forms sharp-cornered ledge ————— 4.0

Siltstone, pale-reddish-brown, friable, structureless; forms slope —————————————— 1.0

Limestone, light-brownish-gray, aphanitic,

resistant, ledge-forming ———————————— 3.5

Sandstone, light-olive-gray, fine- to very fine 

grained; calcareous (18 percent); contains 

jasper; weathers pale-reddish-brown; forms 

ledges with sharp corners ——————————— 4.0

Section 21a (east side)—Continued 

TOROWEAP VALLEY—Continued

Feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Mudstone, dark-reddish-brown, friable; forms

slope ——————————————————————— 4.5

Limestone, light-brownish-gray, aphanitic, resistant, ledge-forming ————————————— 3.5

Limestone, brownish-gray, aphanitic, and 

moderate-reddish-brown mudstone; thin, irregularly bedded (0.5-2 in.), shaly; forms 

slope or recess •——TM—•——-——-——-———— o.u

Limestone, very light gray, silty, platy, aphanitic, ledge-forming; cross-laminated; contains jasper along bedding planes —————— 9.5

Siltstone, light-brown, friable; contains limestone concretions; forms slope ———————— 3.0

Limestone, pale-reddish-purple, aphanitic, 

cross-laminated; contains jasper bands; 

ledge-forming ————————————————— 5.0

Siltstone, grayish-pink, friable, limy, structureless; slope-forming ———————————— 7.0

Limestone, pale-reddish-purple, aphanitic, 

hard; contains chert; weathers brownishblack; forms ledge with sharp corners ———— 4.0

Siltstone, grayish-red, friable, muddy, structureless; slope-forming ———————————— 10.0

Limestone, brownish-gray, aphanitic, crosslaminated; contains jasper bands; ledgeforming ————————————————————— 8.5

Sandstone, grayish-pink, very fine grained, 

cross-laminated; forms ledge ————————— 13.0

Limestone, medium-light-gray, aphanitic;

contains jasper bands; ledge-forming ———— 5.5

Siltstone, light-brown, friable, structureless,

slope-forming ————————————————— 1.0

Siltstone, light-brown mottled with white; 

contains many hard, reddish-gray, spherical 

concretions; forms massive ledge —————— 15.0 

Total cliff unit, Manakacha Formation —————————————144.5 

Total Manakacha Formation —— 144.5

Watahomigi Formation, upper slope unit:

Siltstone, light-brown, friable, thin-bedded,

slope-forming ————————————————— 9.0 

Limestone, light-gray, aphanitic; contains

peloids or lumps of moderate-reddish-brown

mudstone; weathers to knobby surface ——— 4.5 

Siltstone, light-brown, friable, structureless,

slope-forming ————————————————— 6.5
452 THE SUPAI GROUP OF GRAND CANYON

Section 21a (east side)—Continued 

TOROWEAP VALLEY-Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit— 

Continued

Limestone, light-brownish-gray, aphanitic,

cross-laminated; contains jasper bands;

ledge-forming —————————————————

Mudstone, reddish-gray mottled with white,

thin-bedded, shaly; forms slope or recess ——

Siltstone, moderate-reddish-brown, friable,

structureless, slope-forming ———————

Limestone, brownish-gray, aphanitic, crosslaminated; contains jasper bands; ledgeforming —————————————————

Limestone, yellowish-white and light-brown, 

fine-grained, hard; weathers with darkbrownish varnish; forms massive cliff with 

sharp edges ——————————————————— 

Limestone, reddish-gray, aphanitic, sandy, 

thin-bedded (average 6 in.); contains some 

rounded pebbles; contains abundant fossils 

(Orbiculoidea sp., Lingula sp.l, bryozoa, 

gastropods, fish tooth); weathers to 

moderate-brown, irregular surface ——-—— 

Largely concealed; local exposures of calcareous, silty mudstone and siltstone ——————— 

Conglomerate, gray-brown; contains brachiopods; forms ledge ———————————

Matrix: light-brownish-gray siltstone, hard. 

Gravel: Size 0.25-1 in., a few 4 in. in diameter; Shape—angular to subangular; Composition—mostly jasper, some siltstone 

and limestone.

Total upper slope unit, Watahomigi Formation ———————

Watahomigi Formation, middle cliff unit: 

Mudstone, reddish-gray mottled with white, 

thin-bedded, shaly; forms slope —————— 

Limestone, brownish-gray, aphanitic; contains jasper bands; forms massive cliff ——— 

Limestone, brownish-gray; aphanitic, massive; contains no jasper; forms weak ledge — 

Total middle cliff unit, Watahomigi Formation ——————

Watahomigi Formation, basal slope unit:

Mudstone, reddish-gray, shaly; forms slope —— 

Siltstone, light-brown, friable, structureless, 

slope-forming; much concealed —————— 

Conglomerate, gray-brown; forms ledge; contains limestone, sandstone and few jasper 

pebbles; no fossils ————————————

Section 21a (east side)—Continued 

TOROWEAP VALLEY—Continued

Feet feet

2.5

10.5

19.5

5.0 

7.0

5.0

10.5

7.0

87.0

9.0

16.5

4.0

29.5

1.0 

53.5

4.0

Supai Group—Continued 

Watahomigi Formation, basal slope unit— 

Continued

Conglomerate—Continued

Concealed, probably light-brown siltstone —— 21.0 

Total basal slope unit, Watahomigi Formation ——————— 78.5 

Total Watahomigi Formation — 196.0

Total Supai Group ———————— 946.0

Unconformity.

Redwall Limestone:

Limestone, light-brownish-gray, sandy, thickbedded; contains lenses of red beds with 

angular chert pebbles; weathers to pitted, 

cavernous surface; overlies crystalline limestone containing corals and spirifers.

Section 21 b (west side) 

TOROWEAP VALLEY

[On west side of Toroweap Valley (measured at foot of valley, to record 

fossil horizons)]

Feet

Supai Group:

Manakacha Formation, cliff unit. Not measured. 

Watahomigi Formation:

Concealed slope. Not measured.

Sandstone, dark-reddish-brown, very fine 

grained; cross-stratified on medium scale; 

weathers to black, flat face; forms ledge ——

Siltstone, purplish-brown, shaly; forms slope; 

much concealed ————————————-

Sandstone, bright-reddish-brown, very fine 

grained, friable, thin-bedded; forms weak 

ledge or slope —————————————

Siltstone, purplish-brown, shaly; forms slope —

Limestone, light-gray; contains jasper bands; 

forms weak ledge —————————————

Concealed slope ————————————————

Limestone, light-gray, silty, massive; contains shell sections; forms ledge ———————

Concealed slope —————————————

Conglomerate, speckled light-brownish-gray 

on yellowish-gray; contains scattered chert 

pebbles and very coarse grained sand in 

matrix of silt; thin-bedded (2-6 in.); forms 

weak ledge ————————————————

11.0

— 16.0

8.5 

8.5

3.0 

38.5

4.0 

17.0

2.0
MEASURED STRATIGRAPHIC SECTIONS 453

Section 21b (west side)—Continued 

TOROWEAP VALLEY-Continued

Section 21b (west side)—Continued 

TOROWEAP VALLEY—Continued

Feet Feet

Supai Group—Continued 

Watahomigi Formation—Continued 

Conglomerate—Continued

Gravel: chert; light-brown, dark-reddishbrown, grayish-orange-pink; about 33 

percent pebble size, 66 percent granule 

and coarse-grained sand; angular to 

subrounded. 

Matrix: silt; light-olive-gray; calcareous

cement.

Concealed slope; purplish-brown, shaly siltstone locally exposed ———————————— 11.0 

Dolostone, dark-gray, fine-, even-grained;

contains brown wavy laminae; forms ledge — 2.0 

Conglomerate, pale-reddish-brown, thinbedded (1-6 in.); forms receding ledges; 

resembles conglomerate above ———————— 3.0 

Gravel: chert and flint, some jasper; lightbrown, moderate-reddish-brown, grayishorange-pink; common size range 0.06- 

0.25 in.; maximum 0.75 in.; angular to 

subrounded.

Matrix: very coarse grained sand; grayishorange-pink, silty, calcareous. 

Limestone, light-gray, thick-bedded (2-4 ft); 

contains many jasper bands; weathers black 

to brown; forms cliff —————————————— 14.0 

Limestone, pale-gray, aphanitic to fine-grained, 

thick-bedded (2-4 ft), resistant, includes 

brown, silty laminae; forms receding ledges — 13.0 

Mudstone, deep-reddish-brown, brittle,

crumbly; forms slope —————————————— 16.5 

Limestone, dark-gray, aphanitic; includes 

jasper bands; contains wavy (stromatoloid?) 

laminae; forms resistant ledge ———————— 16.5 

Concealed slope; probably siltstone like underlying beds ———————————————————— 15.5 

Siltstone, purplish-brown, shaly; includes few 

thin limestone beds; contains many fossils at 

4 ft above base (M-35, brachiopods, bryozoans) and at 16 ft above base (M-36, 

brachiopods, coral, bryozoans; small 

Spirifers very common); forms slope ———— 16.5 

Conglomerate, light-brownish-gray; contains 

abundant fossils (M-34, brachiopods, 

gastropods, bryozoans); weathers brown —— 2.5 

Gravel: chert; pale-reddish-purple, grayishred; mudstone, dark-reddish-brown; limestone, light-gray, subangular to rounded; 

common size range 0.13-0.25 in.; maximum 0.5 in.

Supai Group—Continued 

Watahomigi Formation—Continued 

Conglomerate—Continued

Matrix: light-gray limestone.

Mudstone, purplish-brown, shaly; forms slope - 13.0 

Siltstone, light-purplish-brown, thin-bedded;

forms weak ledge ———————————————— 3.0 

Mudstone, deep-reddish-brown, crumbly, 

brittle; contains scattered chert pebbles; 

forms slope ——————————————————— 21.0 

Conglomerate, moderate-brown; forms weak 

ledge ————————————-——-—- 3.0-10.0

Gravel: chert, light-brown to dark-reddishbrown; mostly 0.25-0.5 in., maximum 

4-in. diameter; mostly angular, some 

rounded. 

Matrix: moderate-brown, fine-grained quartz

sandstone, weakly cemented. ____ 

Total Watahomigi Formation — 266.0

Unconformity:

Surface of low relief but includes sink hole 

with depth of 14 ft, largely filled with conglomerate.

Redwall Limestone:

Horseshoe Mesa Member. 

Limestone, light-gray, aphanitic.

Section 22a (part) 

WHITMORE WASH

[On east side near the mouth of Whitmore Wash (lower part measured 

in narrow canyon normal to the wash)]

Supai Group:

Top of escarpment: See section 22b for uppermost 

unit. 

Esplanade Sandstone, main cliff unit:

Sandstone, very pale orange, fine- to very 

fine grained, calcareous, friable; crossstratified, mostly tabular-planar, on medium 

to large scale (some 70 ft long); cosets thick 

(3-10 ft); forms massive, rounded cliff ———— 58.0
454 THE SUPAI GROUP OF GRAND CANYON

Section 22a (part)—Continued 

WHITMORE WASH-Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, main cliff unit—

Continued

Sandstone, pale-reddish-brown or laminated, 

red and buff, very fine grained; includes few 

medium grains; prominently cross-stratified, 

low-angle, large-scale (mostly wedgeplanar); cosets 1-3 ft thick; contains two 

light-olive-gray, coarse- to fine-grained 

calcitic dolomite (52 percent) in lenses (1 ft 

thick) near top; forms cliff —————————— 20.5

Sandstone, moderate-orange-pink, very fine 

grained, many fine grains; calcareous, hard, 

structureless; forms weak cliff at base of 

resistant cliff —————————————— 17.5

Sandstone, pale-reddish-brown, very fine 

grained, calcareous, medium-bedded (1-3 

ft); forms series of receding weak, rounded 

ledges or slope; includes some beds of deepred-brown, crumbly mudstone ——————— 18.0

Sandstone, moderate-reddish-orange, fine- to 

very fine grained, slightly calcareous, 

friable; contains small-scale, wedge-planar 

cross-strata in cosets of medium thickness 

(2-5 ft); forms small, reddish-brown cliff —— 15.5

Limestone, light-olive-gray, aphanitic; weathers to pitted surface; locally conspicuous —— 1.0

Sandstone, bright-red-brown; like second bed 

below —————————————————————— 1.5

Sandstone, very pale orange, very fine grained, 

very hard; forms resistant, rounded ledge; 

makes prominent marker ——————————— 2.5

Sandstone, pale-reddish-brown, very fine 

grained, silty (30 percent), calcareous (30 

percent), friable, medium-bedded (1-2 ft); 

forms receding ledges ————————————— 12.0

Sandstone, pale-reddish-brown, very fine 

grained, calcareous, crumbly, slopeforming; includes 1-ft ledge of hard, limy 

sandstone ———————————————————— 6.0

Sandstone, pale-buff, like massive cliff unit 

below —————————————————————— 12.0

Sandstone, moderate-orange-pink, very fine 

grained, calcareous, medium-bedded (2-3 

ft); weathers reddish-brown; forms weak 

ledges, receding locally ———————————— 5.5

Section 22a (part)—Continued 

WHITMORE WASH-Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, main cliff unit— 

Continued

Sandstone, very pale orange, very fine grained; 

includes fine grains; slightly calcareous, 

cross-stratified on large scale (tabularplanar); weathers to rough, yellow-brown 

surface and rounded edges; forms massive 

ciirr ———————————————————————————————_j/ 1 j

Total main cliff unit, Esplanade

Sandstone ——————————— 207.5

Esplanade Sandstone, basal slope unit:

Sandstone, moderate-orange-pink, very fine 

grained, calcareous, friable, thin-bedded 

(2-12 in.); locally contains lenses of algal(?) 

limestone with dark-gray structures prominent; forms slope or receding ledges —————

Sandstone, moderate-reddish-orange, calcareous, very fine grained, silty, platy, slopeSandstone, grayish-pink, very fine grained, 

calcareous, structureless; forms resistant

Sandstone, pale-reddish-brown, very fine 

grained, calcareous, friable; contains small 

limestone nodules in upper part; forms slope 

or receding ledges —————————————

Conglomerate, gray to brown ———————

Matrix: purple, sandy limestone. 

Gravel: Composition—dark-gray limestone, 

olive-gray limestone, pale-gray limestone, 

red-brown siltstone; mostly well-rounded, 

some subangular; mostly range from 0.25 

to 1 in., maximum 2 in.; many limestone 

pebbles are coated with concentric layers 

of olive-green limestone forming band 

about 0.25 in. wide, probably algal 

deposits.

Limestone, pale-reddish-brown and pinkishgray, aphanitic to coarse-grained, resistant, 

cross-stratified throughout (wedge-planar 

and tabular-planar types); some laminae 

contain medium- to coarse-size quartz and 

jasper grains that etch out on surface; 

weathers to ledge with sharp corners, sandy 

surface and conspicuous black laminae ———

4.0

6.5

2.0

11.0 

2.0

5.0
MEASURED STRATIGRAPHIC SECTIONS 455

Section 22a (part)—Continued 

WHITMORE WASH-Continued

Supai Group—Continued 

Esplanade Sandstone, basal slope unit— 

Continued

Sandstone, pale-reddish-brown very fine 

grained, calcareous, friable, medium-bedded 

(1-2 ft); forms receding ledges ——-—-—--—-

Conglomerate, reddish-brown to gray, silty; 

forms resistant ledge ——-

Feet Feet

7.0

2.0

11.0

Matrix: siltstone, reddish-brown. 

Gravel: dark-gray limestone, buff siltstone, 

red-brown siltstone; mostly 0.25-1 in. in 

diameter, maximum 4 in.; most wellrounded, some subangular. ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 39.5 

Total Esplanade Sandstone ——— 247.0

Wescogame Formation, slope unit:

Sandstone, pale-reddish-brown, very fine 

grained, silty, calcareous, friable, flat-, 

irregularly bedded; forms rounded ledge —— 3.0

Sandstone, pinkish-gray, very fine grained, 

slightly calcareous, friable, massive, weakly 

cross-stratified on large-scale; weathers to 

conspicuous white ledge ——————————— 8.5

Sandstone, moderate-orange-pink to yellowbrown, very fine grained, calcareous (28 percent), friable, medium-bedded (1-3 ft); 

weathers bright-reddish-brown, forms series 

of receding rounded ledges —————————— 38.5 

Total slope unit, Wescogame

Formation ——————————— 50.0

15.5

Wescogame Formation, cliff unit:

Sandstone, pale-reddish-brown, very fine 

grained, very limy (40 percent), cross-stratified (tabular-planar); cosets medium-thick 

(1-3 ft); weathers reddish-brown, locally 

with black varnish; forms massive cliff ——— 44.0

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, friable, thin- , flatbedded (0.5-2 in.); forms recess ———————— 2.0

Limestone, pale-reddish-brown, aphanitic; 49 

percent sand (very fine grained); resistant, 

cross-stratified (tabular-planar type); forms 

resistant ledge at base of cliff ————————— 3.5

Section 22a (part)—Continued 

WHITMORE WASH—Continued

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued

Sandstone, pale-reddish-brown, very fine 

grained, calcareous; weakly cross-stratified 

on large-scale, mostly structureless; 

weathers to brown, rounded ledge —————

Sandstone, grayish-pink, very fine grained; 

some fine grains; calcareous, friable, thinbedded (2-12 in.); beds mostly flat, some 

with tabular-planar cross-strata; weathers 

reddish-brown; forms rounded, receding 

ledges ———————————————"——————

Conglomerate, pale-gray to white; weathers 

reddish-brown and dark-brown; forms ledge 1.0 

Matrix: calcareous, fine-grained sandstone. 

Gravel: mostly jasper and white chert, some 

pale-gray limestone, dark-gray limestone; 

generally 0.13-0.25 in. in diameter, maximum 0.25 in.; angular and subangular, 

except limestones that are rounded. ____ 

Total cliff unit, Wescogame

Formation ——————————— 77.0 

Total Wescogame Formation —— 127.0

Manakacha Formation, slope unit:

Limestone, light-brownish-gray, aphanitic, 

insoluble (28 percent), sandy (fine- to very 

fine grained); resistant; breaks with clinkery 

ring; contains many grains of conspicuous 

white kaolinite throughout; prominently 

cross-stratified (tabular-planar and wedgeplanar types) with both high- and low-angle 

laminae; cosets medium-thick (0.5-3 ft); 

weathers with dark-brown laminae in relief; 

rorms clirr ——~——————-————————— ZtZt.\j

Limestone, dolomitic, pale-reddish-brown to 

purple; some parts very silty (49 percent), 

crumbly; consists of two thin beds with 

resistant, aphanitic, medium-gray limestone 

between; forms prominent recess —————— 5.5

Siltstone, moderate-orange-pink, limy, locally 

friable; contains flat beds and cosets of 

tabular-planar cross-strata (6-36 in.); 

weathers to black varnished surface; forms 

weak ledges within main cliff ————————— 15.5 

Total slope unit, Manakacha

Formation ——————————— 43.0
456 THE SUPAI GROUP OF GRAND CANYON

Section 22a (part)—Continued 

WHITMORE WASH—Continued

Section 22a (part)—Continued 

WHITMORE WASH—Continued

Feet Feet

Supai Group—Continued 

Manakacha Formation, cliff unit:

Limestone, pale-reddish-brown, aphanitic, 

very silty, prominently cross-stratified 

(wedge-planar type); surfaces between cosets 

locally consist of very irregular erosion 

planes; weathers with dark-brown laminae 

etched on bluish-gray base; forms cliff with 

angular margins ———————————————— 8.5

Limestone, pinkish-gray, very fine grained; 

medium- to thick-bedded (1-4 ft); contains 

many irregular jasper bands (0.25-3 in. 

thick); locally cross-stratified on medium 

scale; forms cliff or receding ledges ————— 12.0

Limestone, pale-reddish-brown, silty, very 

fine grained; prominently cross-stratified 

(wedge-planar type) on medium scale; contains scattered, ellipsoidal concretions 

oriented parallel to crossbeds; weathers 

dark-brown with cross-strata in prominent 

relief; forms massive cliff ——————————— 16.0

Limestone, grayish-orange-pink, very fine 

grained; stratification weakly developed 

(horizontal strata and small-scale crossstrata; contains many thin layers and concretions of jasper) ——————————————— 3.0

Limestone, light-brownish-gray, aphanitic, 

sandy and silty (44 percent), cross-stratified 

(tabular-planar type) on medium scale; 

weathers with dark-brown varnish; forms 

base of resistant cliff —————————————— 4.0

Mudstone, moderate-reddish-orange, calcareous; contains flat, concretionary bedding 

(beds 1-2 in. thick); forms bench and recess 

under main cliff ————————————————— 2.5

Sandstone, light-gray, aphanitic, limy; weakly 

cross-stratified on small-scale; contains irregular layers of chert and jasper; weathers 

dark-gray; forms resistant ledge ——————— 7.0

Concealed slope, brittle, silty, pale-red limestone locally exposed near top ———————— 5.0 

Manakacha Formation, cliff unit:

Limestone, light-gray, thin- to medium-bedded 

(1-24 in.), aphanitic; contains irregular 

layers of jasper (0.5-3 in. thick); forms series 

of weak ledges ————————————————— 17.5

Concealed slope ————————————————— 5.0

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Limestone, pale-reddish-brown, aphanitic, 

silty; includes cosets with thin, flat laminae 

and low-angle cross-laminae (2-3 ft thick); 

weathers with black varnish irregularly 

distributed ———————————————————— 5.0 

Concealed slope, pale-reddish-brown, shaly 

siltstone with limy concretions and jasper 

lenses locally exposed ————————————— 11.0 

Sandstone, grayish-red, very fine grained, calcareous, speckled brown; includes many fine 

grains; friable; cross-stratified on medium 

scale; weathers pink with brownish spots; 

forms weak, rounded ledges ————————— 28.0 

Total cliff unit, Manakacha

Formation ——————————— 124.5 

Total Manakacha Formation —— 167.5

Watahomigi Formation, upper slope unit:

Siltstone, grayish-orange-pink, shaly, thinbedded (0.25-2 in.); locally contains mudballs and wavy structure; forms slope ———— 16.5 

Concealed slope, basal third with local exposures of reddish-brown, crumbly sandstone and pale reddish-brown shaly siltstone —————————————————————— 70.0 

Conglomerate, weathers brown to gray; forms 

resistant, rounded ledge ——————————— 6.0 

Matrix: finely-crystalline limestone. 

Gravel: exclusively durable rocks including 

jasper, white and brown chert; mostly 

0.25-0.5 in. in diameter, maximum 0.5 

in.; angular to subrounded. ____ 

Total upper slope unit, Watahomigi Formation ——————— 92.5

Watahomigi Formation, middle cliff and lower 

slope units:

Concealed slope ————————————————— 10.0 

Limestone, pale-yellowish-brown, fine-grained;

thin-bedded (6-12 in.); forms receding ledges 12.5 

Concealed slope ————————————————— 6.0 

Limestone, medium-light-gray, even-grained, 

medium-bedded (2-3 ft); contains thin jasper 

layers; cut with many calcite veins; forms 

weak ledges —————————————————— 11.0
MEASURED STRATIGRAPHIC SECTIONS 457

Section 22a (part)—Continued 

WHITMORE WASH-Continued

feet

Supai Group—Continued 

Watahomigi Formation, middle cliff and lower 

slope unit—Continued

Limestone, medium-light-gray, rubbly, irregularly bedded, brittle; forms weak ledges on 

slope —————————————————————— 1.0 

Limestone, light-gray with purple blotches; 

aphanitic; contains few jasper lenses and 

crosscutting veins; forms ledge ———————— 7.5 

Concealed slope ————————————————— 11.0 

Limestone, medium-light-gray, fine-grained, 

thin-bedded (2-12 in.); contains much jasper 

(50 percent) in wavy layers and one bed of 

concretions (0.25 in. diameters); forms weak 

ledge —————————————————————— 6.0 

Limestone, olive-gray and dark-greenish-gray, 

aphanitic, medium-bedded (1-2 ft); forms 

rounded ledge ————————————————— 5.0 

Conglomerate, gray to brown, thin-bedded (4- 

12 in.); grades into conglomeratic limestone; 

contains many fossils (brachiopods, crinoid 

joints, trilobites, gastropods), concentrated 

locally, also scattered among pebbles ———— 2.5 

Matrix: aphanitic to fine-grained limestone. 

Gravel: mostly durable rocks including 

flint, chert, and quartzite; some dark-gray 

and light-gray limestone and red-brown 

siltstone; largely 0.25-0.5 in. in diameter, 

maximum 1 in.; subangular to rounded. 

Claystone, dark-reddish-brown with white 

deoxidation spots; structureless; brittle; 

forms slope ——————————————————— 13.0 

Total middle cliff and lower 

slope units, Watahomigi Formation ————————————— 86.5 

Total Watahomigi Formation — 178.0 

Total Supai Group ———————— 719.5

Unconformity:

Irregular surface with small relief (a few feet

in one-half mile exposure). 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, light-olive-gray, aphanitic, thinto medium-bedded (6-24 in.); weathers to 

rough, pitted surface; forms receding ledges.

Section 22b (part) 

WHITMORE WASH

[Complete Esplanade section on east side of Whitmore Wash; measured 

north of section 22a, between major basalt cascades]

Feet

Hermit Shale:

Sandstone, moderate-reddish-brown, very fine 

grained (angular), micaceous, platy; forms 

series of weak ledges (2-8 in. thick); fills 

channels in top of Supai ——————————— 24.0

Unconformity:

Channels 10-15 ft deep in massive sandstone 

of Supai, filled with platy sandstone and siltstone of Hermit. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope unit:

Sandstone, pale-reddish-brown to moderatereddish-brown, very fine grained (angular), 

platy; silty near top; forms receding ledges — 44.0

Sandstone, moderate-reddish-orange, very fine 

grained (93 percent), subrounded, thickbedded (1-4 ft), flat-bedded; forms resistant, 

rounded cliff ~—————-—————-—————- 71.5

Sandstone, moderate-reddish-orange, very fine 

grained (angular) with concentration of 

medium-grained sand, well-rounded, 

frosted, limy (45 percent); poor sorting; 

thin- to thick-bedded (0.5-3 ft), friable; 

forms bench and rounded ledges with quartz 

grains etched out on surface; thin, platy siltstone at top ——————————————————— 33.0 

Total upper cliff-slope unit,

Esplanade Sandstone ————— 148.5 

Esplanade Sandstone, main cliff unit:

Sandstone, moderate-reddish-orange, mediumto very fine grained, and pale-reddishbrown, very fine grained (74 percent) sandstone; total cross-stratified on large scale 

(20-30 ft); forms resistant cap rock for major 

cliff; pit holes from solution common ———— 36.0

Sandstone, moderate-reddish-orange (lower 

and middle part), very fine grained, subrounded (75 percent); to moderate-orangepink (upper), very fine grained (subangular); 

silty in upper part; cross-stratified on 

medium to large scale; sets of strata very 

thick (10-20 ft); forms cliff, weaker and 

more rounded than underlying ———————— 82.5
458 THE SUPAI GROUP OF GRAND CANYON

Section 22b (part)—Continued 

WHITMORE WASH-Continued

Supai Group—Continued 

Esplanade Sandstone, main cliff unit—

Continued

Sandstone, moderate-reddish-orange, fine- 

(82 percent) to very fine grained (round to 

subrounded), calcareous (36 percent), lower 

part, and moderate-reddish-brown, very 

fine grained (angular), silty (upper part) 

sandstone; very thick bedded (10-30 ft); 

cross-stratified on medium to large scale; 

forms lower half of major cliff; weathers to 

sheer face with brown to black varnish ———

Sandstone, moderate-orange-pink; very fine 

grained (subrounded), very thick bedded 

(4-10 ft); flat-bedded (near base), mediumscale cross-bedding above; contains some 

fine-grained sand in upper part; laminae of 

sand etched out; forms basal part of main 

cliff; weathers to straight face; pink in these 

beds contrasts with orange above ——————_

Feet

80.0

16.5

Total main cliff unit, Esplanade

Sandstone ——————————— 215.0 

Total Esplanade Sandstone ——— 363.5

Section 23 

PARASHANT CANYON

[East of Shivwits Plateau]

Feet

Hermit Shale: 

Contact:

Unconformity not observed at this locality. 

Supai Group:

Esplanade Sandstone, upper cliff-slope unit (part); 

Sandstone, grayish-orange to moderatereddish-orange, very fine grained, locally 

quartzitic, friable, highly cross-stratified; 

weathers with weak-brown varnish on surface; forms resistant cliff with sharp edges — 55.0 

Mudstone, moderate-reddish-brown, shaly;

forms slope ——————————————————— 12.0 

Sandstone, pale-yellowish-orange, very fine 

grained, friable; forms cliff —————————— 5.5 

Total upper cliff-slope unit

(part), Esplanade Sandstone — 72.5

Section 23—Continued 

PARASHANT CANYON-Continued

Supai Group—Continued

Esplanade Sandstone, upper cliff-slope unit,

gypsiferous f acies:

Siltstone, moderate-orange-pink, thin-bedded 

to shaly; includes some friable, very fine 

grained (scattered fine grains) sandstone 

beds and beds of gypsum; forms slope with 

few small ledges —————————————

Total upper cliff-slope unit, gypsiferous facies, Esplanade 

Sandstone —————— 

Total upper cliff-slope unit, 

Esplanade Sandstone ————— 

Esplanade Sandstone, main cliff unit:

Sandstone, moderate-orange-pink, very fine 

grained, well-sorted, cross-stratified; forms 

receding ledge ———————————————

Sandstone, moderate-orange-pink, silty, shaly, 

slope-forming ———————————————

Sandstone, moderate-orange-pink to moderate-reddish-orange, very fine grained 

(scattered fine grains), silty (18 percent); 

cross-stratified on medium to large scale, 

friable, calcareous (34 percent); forms resistant cliff and rim of Esplanade ———————— 

Sandstone, grayish-orange-pink, very fine 

grained; contains white chert specks; crossstratified (medium-scale); forms small cliff 

with bench at base —————————————

Sandstone, moderate-orange-pink, very fine 

grained (scattered fine grains), silty (20 percent), calcareous (33 percent); crossstratified on medium to large scale, thickbedded; forms massive cliff ———————

Sandstone, moderate-reddish-orange, finegrained, bimodal, calcareous, silty, flatbedded; forms bench ————————————

Sandstone, moderate-reddish-orange (upper) 

to moderate-orange-pink (lower), and 

medium-grained (rounded, 11 percent), upper part bimodal, calcareous (33 percent); 

thin- to medium-bedded; weathers to white 

or pale-gray surface; forms weak cliff with 

bench or slope at base ————————————

Sandstone, grayish-orange-pink, very fine

grained, limy (25 percent), medium- to

thick-bedded; forms resistant cliff ——————_

Total main cliff unit, Esplanade

Sandstone ——————————

Feet

73.5

— 73.5 

146.0

12.0 

6.0

38.5

14.0

63.5

11.0

9.5

28.5

183.0
MEASURED STRATIGRAPHIC SECTIONS 459

Section 23 — Continued 

PARASHANT CANYON-Continued

Feet

Supai Group — Continued

Esplanade Sandstone, basal slope unit:

Sandstone, pale-reddish-brown to grayishpink, very fine grained, locally limy (42 percent), thin- to medium-bedded; forms weak 

receding ledges or slope ———————————— 22.0 

Sandstone, reddish-orange, very fine grained, 

calcareous; forms weak ledge ————————— 30.0 

Total basal slope unit, Esplanade Sandstone ———————— 52.0 

Total Esplanade Sandstone ——— 381.0

Wescogame Formation, slope unit:

Sandstone, very pale brown, mottled with 

light-brown; very fine grained, silty, calcareous, prominently cross-laminated; forms 

cliff _______________________ 20 0

Sandstone, pale-reddish-brown (upper 3 ft 

very pale brown), very fine grained (subangular), calcareous, argillaceous; weathers 

moderate-brown; forms ledge ———————— 21.0

Sandstone, moderate-reddish-brown, very fine 

grained, friable; forms slope ————————— 1.5

Sandstone, light-brown, very fine grained, 

calcareous; massive; forms ledge ——————— 4.5

Sandstone, moderate-reddish-brown, very 

fine grained, friable; forms slope ——————— 4.5

Sandstone, strong-reddish-brown, very fine 

grained (angular to subangular), friable, 

highly cross-laminated; weathers same; 

forms weak, rounded ledges ————————— 12.0

Sandstone, light-brown, very fine grained, 

very friable, brittle; weathers same; forms

Total slope unit, Wescogame

Formation —————————

Wescogame Formation, cliff unit:

Sandstone, reddish-gray, very fine grained, 

silty, cross-laminated on large scale; two 

lower beds about 10 ft thick, upper bed 50 ft, 

separated by reddish-brown siltstone partings locally; grades above into friable, red 

silt stone ————————————————————————————

74.5

75.0 

Conglomerate, forms massive ledge ——————- 2.0

Gravel: elliptical, unoriented, limestone 

pebbles (diameter 0.25-6 in.). ____ 

Total cliff unit, Wescogame Formation ————————————— 77.0 

Total Wescogame Formation —— 151.5

Section 23—Continued 

PARASHANT CANYON—Continued

Supai Group—Continued 

Manakacha Formation, slope unit:

Siltstone, moderate-reddish-brown, friable, 

weak, structureless; contains abundant impressions of Walchia —————————- 

Limestone, reddish-gray, aphanitic, silty, friable, thin-bedded (1-2 ft); weathers with 

silty surface; forms weak ledges ————— 

Limestone, reddish-gray, fine-grained, prominently cross-laminated; forms ledge ————— 

Limestone, reddish-gray, flat-bedded; forms

Feet

—- 2.0

12.0 

4.5

------ 1.0

Claystone, weak-reddish-brown, very thin 

bedded, crumbly; forms slope ———————— 1.0

Limestone, reddish-gray, fine-grained, thinbedded (1-2 ft); forms weak, receding ledges 9.0

Limestone, reddish-gray, fine-grained, hard; 

much cross-laminated in scour-and-fill type; 

forms ledges with rounded or sharp edges — 10.0

Claystone, weak-reddish-brown, very thin 

bedded; crumbly; forms slope ———————— 5.0

Sandstone, reddish-gray, very fine grained 

(angular), silty, calcareous, friable; weathers 

brown; forms rounded ledge ————————— 4.5

Claystone, pale-reddish-brown, thin-bedded, 

crumbly; forms slope ————————————— 2.5 

Total slope unit, Manakacha

Formation ——————————— 51.5

Manakacha Formation, cliff unit:

Limestone, dark-reddish-gray, fine-grained, 

cross-laminated; beds thick (5-10 ft); contains a few jasper lenses; weathers reddishbrown; locally forms crumbly cliff —-———— 62.0 

Conglomerate, rusty-brown to gray, base of 

cliff—————————-———————— i.o

Matrix: clastic limestone, gray. 

Gravel: abundant small (0.06-0.13 in.), 

angular, jasper and chert fragments and 

few scattered, subangular to subrounded, 

gray, fine-grained limestone pebbles 

(0.5-2 in.). 

Claystone, pale-reddish-brown, thin-bedded,

crumbly; forms slope ————————————— 1.0 

Limestone, light-brownish-gray, aphanitic, 

hard; cross-laminated on large-scale; contains a few jasper bands; weathers brownishgray or weak-brown; forms ledges 10-15 ft 

thick with thin shale partings ————————— 45.0
460 THE SUPAI GROUP OF GRAND CANYON

Section 23 — Continued 

PARASHANT CANYON— Continued

Supai Group — Continued

Manakacha Formation, cliff unit — Continued 

Limestone, reddish-gray, aphanitic; contains

jasper bands; forms cliff ———————————— 

Claystone, pale-reddish-brown, thin-bedded,

crumbly; forms slope —————————————— 

Limestone, reddish-gray with bands of palebrown, aphanitic, sandy (very fine grained);

contains jasper bands; weathers palereddish-brown; forms cliff —————————— 

Claystone, pale-reddish-brown, thin-bedded,

crumbly; forms slope —————————————— 

Limestone, reddish-gray, aphanitic, silty, thinbedded; weathers with silty surface; forms

Claystone, pale-reddish-brown, thin-bedded,

crumbly; forms slope —————————————— 

Limestone, reddish-gray, aphanitic, silty; contains many jasper bands; very resistant near

top; forms small cliff —————————————— 

Total cliff unit, Manakacha Formation

Total Manakacha Formation —— 

Watahomigi Formation:

Claystone, pale-reddish-brown, very thin

bedded, crumbly; forms slope ———————— 

Limestone, reddish-gray, aphanitic, silty;

forms ledge ——————————————————— 

Claystone, pale-reddish-brown, very thin

bedded, crumbly; forms slope ———————— 

Limestone, reddish-gray, aphanitic; forms

thin beds; contains some jasper; forms series

of thin ledges —————————————————— 

Claystone, pale-reddish-brown, very thin

bedded, crumbly; forms slope ———————— 

Limestone, reddish-gray, with bands of lightbrownish-gray; aphanitic, silty; contains

many jasper bands; weathers with lightbrown stain; forms cliff ———————————— 

Claystone, pale-reddish-brown, very thin

bedded, crumbly; forms slope ———————— 

Limestone, brownish-gray, aphanitic, silty,

hard; weathers light-brownish-gray, silty;

forms rounded ledge —————————————— 

Claystone, pale-reddish-brown, very thin

bedded, crumbly; forms slope ———————— 

Limestone, light-brownish-gray, aphanitic,

sandy (very fine grained, some fine-grained);

contains much jasper; weathers pale-brown,

silty; forms ledge with sharp corners —————

4.5 

3.0

4.0 

1.5

7 ^ / .<J

2.5 

14.5

146.5

198.0

2.5 

2.5 

1.5

14.0 

2.5

8.5 

2.0

1 . 5 

1.5

9.0

Feet

3.0

22.0

10.5

Section 23—Continued 

PARASHANT CANYON—Continued

Supai Group—Continued 

Watahomigi Formation—Continued

Claystone, pale-reddish-brown and yellowishwhite, soft; forms rounded knobs ——————

Limestone, dark-reddish-gray, very silty; beds 

thin and wavy; grades upward into massive, 

aphanitic, reddish-gray limestone containing 

jasper bands; weathers pale-brown —————

Limestone, reddish-gray, very silty, very thin 

bedded (0.25-0.5 in.); weathers palereddish-brown, silty, forms cliff ———————

Siltstone, very pale orange, mottled with paleyellow, calcareous (24 percent), dolomitic, 

aphanitic, very silty; contains molds of 

fossils; weathers light-brown, silty surface; 

forms prominent ledge with sharp edges and 

straight faces ——————————————————

Limestone, light-olive-gray, aphanitic, hard; 

beds average 6 in.; contains ooids; contains 

fossils (crinoids); weathers dusky-yellow, 

oolitic —————————————————————— 

Concealed, probably pale-reddish-brown mudLimestone, pale-brown or very pale brown, 

coarse-grained, soft; beds average 1 ft, with 

thin, mud parting planes and fucoidal structures in many places; contains abundant 

fossils, especially at base (trilobite, 

gastropods, brachiopods); weathers same or 

pale-yellow; forms weak ledges ————————

Claystone, very pale brown, shaly, calcareous; cross-laminated on small scale; 

weathers pale-brown and reddish-gray, 

ripple- and irregularly bedded limestone, 

contains some mud films; weathers same ——

Claystone, pale-reddish-brown, slightly silty,

crumbly; lacks bedding; forms slope ————— 33.0

Conglomerate, fills erosion channels —————— 0-3.0 

Matrix: dark-brown silt. 

Gravel: jasper, chert, and other durable 

materials; average diameter 2 in., maximum 6 in.; well-rounded. ____ 

Total Watahomigi Formation — 177.5 

Total Supai Group ———————— 908.0

Unconformity. 

Redwall Limestone.

10.0

8.0

13.0

27.5

2.0
MEASURED STRATIGRAPHIC SECTIONS 461

Section 24 

ANDRUSCANYON

[Upper part measured on canyon wall about 2 miles southeast of Grassy 

Mountain; lower part on southwest side of canyon, west of fault zone 

about 9 miles southeast of Grassy Mountain]

Feet

Hermit Shale:

Concealed, long slope; probably mostly shaly, 

red-brown siltstone —————————————— 38.5

Contact:

Not well-exposed, but apparently flat, even

surface. 

Supai Group:

Esplanade Sandstone, upper cliff-slope unit (part): 

Sandstone, grayish-orange-pink to moderateorange-pink, very fine grained, with scattered fine grains (26 percent); limy (49 percent), cross-stratified on large scale (laminae 

20-30 ft long); very resistant; forms straight 

face with black varnish; makes massive cap 

rock of cliff; thickness of 55 ft at about 2 mi. 

farther east ——————————————————— 11.0 

Sandstone, moderate-reddish-orange, very fine 

grained, friable, thin- , flat-bedded; forms 

slope —————————————————————— 12.0 

Sandstone, grayish-orange-pink, very fine 

grained, dolomitic (38 percent); weakly 

cross-stratified, medium-scale; weathers yellowish; forms base of cliff unit ———————— 11.0 

Total upper cliff-slope unit

(part), Esplanade Sandstone — 34.0

Erosion Surface.

Esplanade Sandstone, upper cliff-slope unit,

gypsiferous facies:

Sandstone, moderate-reddish-brown, very fine 

grained, friable, flat-bedded, largely concealed; forms slope —————————————— 22.0

Gypsum, white, bedded; and moderate-reddish-orange, very fine grained, calcareous 

(37 percent), friable, sandstone stratified on 

small scale near top; forms weak cliff ———— 28.5

Siltstone, moderate-reddish-brown, argillaceous, shaly; forms slope ——————————— 4.5

Sandstone, moderate-reddish-orange, very fine 

grained, silty (27 percent), calcareous (31 

percent), cross-stratified on medium scale; 

forms cliff ———————————————————— 21.0

Concealed, talus slope; flat-bedded sandstone,

moderate-reddish-orange, locally exposed — 17.0

Feet

22.0

Section 24—Continued 

ANDRUS CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope unit, 

gypsiferous facies—Continued 

Sandstone, moderate-reddish-orange, very 

fine grained, dolomitic (34 percent); thin to 

medium bedding sets (0.5-2 ft); massive 

units cross-stratified; friable; includes some 

thin mudstone and siltstone beds; forms 

weak ledges and slopes ———————————— 

Total upper cliff-slope unit, 

gypsiferous facies, Esplanade 

Sandstone —————————— 115.0 

Total upper cliff-slope unit,

Esplanade Sandstone ————— 149.0

Esplanade Sandstone, main cliff unit:

Sandstone, moderate-orange-pink, very fine 

grained, limy; weathers to gray, rough surface; forms resistant cap rock —————————

Siltstone, moderate-reddish-orange, fissile, 

shaly; forms bench ———————————•

Sandstone to dolostone, pale-red to pale5.0

- 5.5

reddish-brown, very fine grained (angular to 

subangular), dolomitic (50 percent), friable; 

forms massive, cross-stratified units 

(laminae 40 ft long); weathers to brown or 

light-gray, rounded ledges —————————— 33.0

Sandstone, pale-reddish-brown, very fine 

grained, thin-bedded (6-12 in.), flat-bedded; 

forms slope ——————————————————— 5.5

Sandstone, moderate-reddish-orange to palereddish-brown, very fine grained, calcareous 

(25 percent); locally contains white kaolin 

specks; cross-stratified on large scale 

(tabular-planar) upper part, and medium 

scale (wedge-planar) lower part; locally contains recesses of thin, shaly, moderatereddish-orange siltstone; forms massive cliff - 60.5

Dolostone, grayish-orange-pink, granular, insoluble (20 percent), flat-bedded; forms 

bench -————________—______ 28.5

Sandstone, pale-reddish-brown and grayishpink, laminated, medium- to very fine 

grained (subrounded), poorly sorted, calcareous (35 percent); wedge-planar crossstratification (medium-scale); forms massive 

sets (10-15 ft thick); uppermost part granular, pale-reddish-brown dolomite; total 

weathers to gray-brown surface; forms cliff — 60.0
462 THE SUPAI GROUP OF GRAND CANYON

Section 24—Continued 

ANDRUS CANYON-Continued

Supai Group—Continued

Esplanade Sandstone, main cliff unit—Continued 

Sandstone, moderate-reddish-orange, very fine 

grained (angular grains), calcareous (22 percent), silty (25 percent), massive; contains 

layers with abundant brown sand concretions (0.5-0.75 in. diameter); forms rounded 

ledge with conspicuous pale-gray surface ——_

Feet

19.0

Total main cliff unit, Esplanade

Sandstone ——————————— 217.0

Esplanade Sandstone, basal slope unit:

Concealed, talus slope with local outcrops of 

shaly, dark-reddish-brown mudstone ———— 16.5

Sandstone, moderate-reddish-orange, very 

fine grained, silty (37 percent), calcareous 

(35 percent); forms small cliff ————————— 15.0

Concealed, talus slope with local outcrops of 

shaly dark-reddish-brown mudstone ———— 22.0

Sandstone, moderate-reddish-orange, very fine 

grained (angular grains), calcareous (39 percent), cross-stratified, tabular-planar on 

large scale (laminae 50 ft long) in upper part; 

wedge- and tabular-planar, small- to 

medium-scale near base; forms prominent 

r^1111 ijff ______________________ —.«———— -.-.-. __ OO,\J -j-2 n

Total basal slope unit, Esplanade

Sandstone ——————————— 86.5 

Total Esplanade Sandstone ——— 452.5

Wescogame Formation, slope unit:

Sandstone, moderate-reddish-orange, very fine 

grained, silty (13 percent), dolomitic (32 percent), thin-bedded (1-2 ft), flat-bedded; 

forms ledges at base of cliff —————————— 6.0

Sandstone, moderate-reddish-brown, very fine 

grained; includes sandy (40 percent) limestone; forms series of ledges, 1-2 ft thick; 

mostly concealed ———————————————— 23.0

Concealed, slope, probably shaly siltstone —— 12.0

Sandstone, moderate-reddish-orange, very fine 

grained, massive; surface locally black; 

forms weak ledge ———————————————— 6.0

Sandstone, pale-reddish-brown, very fine 

grained, calcareous, friable; prominent 

scour-and-fill bedding; forms weak cliff ——— 8.5 

Total slope unit, Wescogame

Formation ——————————— 55.5

Section 24—Continued 

ANDRUS CANYON-Continued

Feet

Supai Group—Continued

Wescogame Formation, cliff unit:

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous (37 percent), silty, 

crumbly, medium-bedded (1-2 ft); weathers 

red-brown; forms rounded, receding ledges; 

partly concealed ———————————————— 35.5

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, weakly cross-stratified 

on large-scale (units 10-15 ft); forms massive 

rLllll ijff _ ————————— _ _ _ _________________ -.«———— ___ O\J,\J -in n

Concealed slope ————————————————— 1.5 

Sandstone, pale-reddish-brown, very fine 

grained, calcareous; massive bed; weathers 

to rounded black surface; forms part of cliff - 5.5 

Siltstone, brown to white, laminated, friable; 

forms recess —————————————————— 1.0 

Total cliff unit, Wescogame

Formation ——————————— 73.5

Total Wescogame Formation —— 129.0

Manakacha Formation, slope unit:

Limestone, pale- to dark-gray, very sandy; 

planar cross-strata etched out on surface; 

forms cliff ———————————————————— 5.0

Limestone, purple, sandy, thin- to mediumbedded (0.5-2 ft); forms two receding ledges - 11.0

Concealed slope ————————————————— 7.0

Sandstone, grayish-orange-pink, very fine 

grained, limy (20 percent), weakly crossstratified; surface black; forms rounded

Sandstone, light-brownish-pink, silty, limy, 

thin- to medium-bedded (0.5-2 ft); forms 

series of receding ledges ———————————— 12.0 

Concealed slope ————————————————— 8.0 

Total slope unit, Manakacha

Formation ——————————— 57.0

Manakacha Formation, cliff unit:

Limestone, grayish-pink, very limy; and siltstone with cross-strata etched out on surface; forms cliff ————————————————— 17.5

Limestone, grayish-pink with yellowish-gray, 

sandy (very fine grained, scattered mediumgrains), sandstone; weakly cross-stratified in 

upper part; forms rounded ledge ——————— 17.0

Sandstone, grayish-orange-pink, very fine 

grained, limy (31 percent), friable, thinbedded (6-12 in.); forms rounded ledges on
MEASURED STRATIGRAPHIC SECTIONS 463

Section 24 — Continued 

ANDRUS CANYON— Continued

Supai Group — Continued 

Manakacha Formation, cliff unit — Continued 

Limestone, medium-light-gray, mediumgrained, sandy; planar cross-stratified;

forms cliff ———————————————

Limestone, dark-olive-gray, very fine grained;

contains abundant jasper (50-60 percent);

weathers to pitted surface; forms part of cliff 

Limestone, medium-light-gray with light-olivegray, very fine grained, very sandy; planar

cross-strata etched out on surface; weathers

dark-brown to black; forms cliff ———— ——— 

Limestone, dolomitic, medium-light-gray, very

fine grained; weathers to rough gray surface;

contains jasper bands; forms base of large

Concealed slope ————————————————

Limestone, grayish-red-purple, streaked, silty, 

very fine grained, irregularly bedded; contains jasper lenses; forms ledge — —— —— —

Siltstone, brown to white, laminated, friable; 

forms bench ————————————————

Limestone, medium-light-gray, very fine 

grained; weathers to pitted surface; contains 

abundant, irregular, jasper lenses; forms

Feet

Concealed slope ———————————————

Limestone, purple to gray, fine-grained, irregularly bedded; contains jasper lenses; forms

Siltstone, brown, laminated, friable; forms

bench and slope ————————————

Limestone, medium-light-gray, streaked, finegrained, silty; contains jasper lenses; forms

Siltstone, brown to white; laminated; friable; 

forms slope ————————————————

Siltstone, light-brownish-gray, streaked, very 

limy, irregularly bedded; contains jasper 

lenses; forms ledge ——— —— ———— — ———

Siltstone, brown; laminated, friable; forms

Limestone, light-brownish-gray with yellowish-gray streaks, fine-grained, irregularly 

bedded; contains jasper lenses; forms ledge —

Sandstone, grayish-orange-pink, very fine 

grained, very calcareous; compound planar 

cross-stratified on medium scale (3-15 ft); 

weathers to black face; forms base of cliff 

with underlying bed ————————————

18.5

5.5

19.0

5.5 

2.0

6.0 

1.5

6.0

5.5

3.0 

2.0

8.0 

3.0

5.5 

2.0

5.5

Section 24—Continued 

ANDRUS CANYON-Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Limestone, very pale gray with dark-reddishbrown, very fine grained, sandy; planar 

cross-stratified; contains prominent jasper 

bands; forms base of cliff with overlying

Total cliff unit, Manakacha ForFeet

Q

mation ————————————— 169.5 

Total Manakacha Formation —— 226.5 

Watahomigi Formation:

Limestone, moderate-reddish-orange with 

pale-greenish-gray, very fine grained, silty, 

laminated, friable; contains rows of hard, 

brown, concretionary limestone masses; 

forms bench and recess ———————————— 5.0

Limestone, pale-greenish-gray with streaks 

of light-brownish-gray, fine-grained, silty; 

contains abundant irregular bands of jasper 

forming as much as 70 percent of rock; 

forms resistant ledge —————————————— 7.0

Siltstone, grayish-reddish-brown, shaly, calcareous, weakly developed laminae; weathers brown to black; forms weak cliff and

Limestone, dolomitic, dark-grayish-red to 

purple, very fine grained, very silty, irregularly bedded; contains jasper bands and concretions; forms weak ledge and slope ———— 8.0 

Concealed slope ————————————————— 24.0 

Limestone, dolomitic, moderate-reddishbrown, silty, brittle, structureless; weathers

vermilion; forms slope ————————————

Concealed slope —————————————————

Dolostone, calcitic, pale-reddish-purple, silty,

coarse- to medium-grained; weathers to

Claystone, purple, structureless, brittle; forms

18.5

Limestone, medium-light-gray, coarse- to 

medium-grained, silty; forms ledge —————

Limestone, olive-gray, aphanitic, irregularly 

bedded, crumbly; contains much jasper; 

forms slope, largely concealed ————————

Limestone, yellowish-gray, fine-grained with 

scattered large crystals as much as 2 mm, 

silty, medium-bedded (1-4 ft); contains 

jasper bands near top; weathers to darkgray; forms ledge ————————————————

Concealed slope —————————————————

5.5 

16.5

O,\J "\ C\ 

/ ^ _i..j

3.0 

13.5

17.5 

2.0
464 THE SUPAI GROUP OF GRAND CANYON

Section 24—Continued 

ANDRUS CANYON—Continued

Feet

Supai Group—Continued 

Watahomigi Formation—Continued 

Limestone, light-brownish-gray, coarsegrained, with scattered crystals as large as 

3 mm, medium-bedded (1-3 ft); weathers to 

dark-gray, silty surface; forms ledge ————— 6.0

Concealed slope; probably red-brown mudstone ——————————————————————— 8.0

Limestone, medium-light-gray, coarse- to 

medium-grained, with a few crystals as 

much as 3 mm; medium-bedded (1-3 ft); 

forms ledge ——————————————————— 4.0

Claystone, purple, structureless, brittle; forms

slope, largely concealed ———————————— 3.0

Conglomerate, purple to gray, thin-bedded;

contains fish tooth, abundant Composite;

forms weak ledge ———————————————— 3.0

Matrix: pale-reddish-purple limestone.

Pebbles: commonly 0.25-0.5 in. in diameter, many 0.13 in. in diameter; wellrounded; pale-reddish-brown siltstone, 

olive-gray limestone and pale-red limestone.

Limestone, grayish-pink, aphanitic, very silty,

structureless, brittle; forms slope ——————— 5.5

Limestone, grayish-pink with pale-reddishbrown spots, coarse- to very coarse grained, 

thin-bedded (0.5-1 ft); contains abundant 

fossil fragments, especially crinoids; 

weathers to dark-gray; forms receding ledges 2-4.0 

Total Watahomigi Formation — 164.0 

Total Supai Group ———————— 972.0

Unconformity:

Even, regular surface where observed. Local 

depressions as deep as 4 ft filled with clastic 

limestone of Supai.

Redwall Limestone: 

Horseshoe Mesa Member: 

Limestone, yellowish-gray, aphanitic to very 

fine grained, thin- to medium-bedded; forms 

receding ledges.

Section 25 

TWIN SPRINGS CANYON

[Lower part measured on west side of canyon; Esplanade Sandstone 

measured on east side]

Feet

Hermit Shale:

Basal unit: slope with thin ledges.

Siltstone, reddish-brown, thin-bedded (2-24 

in.); forms weak ledges, each 2-6 ft thick; 

and pale-reddish-brown, slightly calcareous, shaly mudstone; forms slopes between ledges; total forms long slope, much 

concealed —————————————————— 60.5

Contact:

Conformable where observed; even, flat surface for 0.25 mile.

Supai Group: 

Esplanade Sandstone, main cliff unit:

Sandstone, very pale orange, very fine grained, 

(includes much fine-grained sand), calcareous, thick-bedded (3-4 ft); massive; weathers to prominent cliff with rounded edges —— 19.5

Sandstone, moderate-reddish-orange, very fine 

grained (subrounded), calcareous, shaly to 

weakly thin-bedded; forms slope ——————— 28.5

Siltstone, buff; contains many trace fossils 

(tubes 0.13 in. in diameter extending vertically); forms resistant ledge ————————— 4.0

Sandstone, moderate-reddish-orange, very fine 

grained, friable, cross-stratified on medium 

scale; forms weak ledge or slope with redbrown siltstone at base ———————————— 16.5

Sandstone, moderate-orange-pink, very fine 

grained (subrounded), calcareous, very friable, cross-stratified on medium scale; forms 

slope ————————————————————————————————————————————— /. u

Sandstone, moderate-orange-pink, very fine 

grained (subrounded), calcareous, thinbedded (6-12 in.); bedding weak and irregular, locally shaly; forms slope ————————— 27.5

Concealed slope ————————————————— 17.0 

Sandstone, grayish-orange-pink, very fine 

grained, limy, contains many trace fossils 

(vertical tubes 0.13 in. in diameter); forms 

resistant ledge ————————————————— 3.0
MEASURED STRATIGRAPHIC SECTIONS 465

Section 25—Continued 

TWIN SPRINGS CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, main cliff unit—

Continued

Sandstone, moderate-reddish-orange, very fine 

grained (subrounded), calcareous, structureless; commonly forms slope, locally weak 

ledges; contains a thin, weak ledge of very 

friable yellow-brown sandstone; very fine 

grained, limy; total forms slope, much concealed——————————————————

Sandstone, moderate-orange-pink, very fine 

grained, platy, calcareous, friable, crossstratified on medium scale; forms weak ledge

Siltstone, reddish-brown, shaly; forms slope ——

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous, friable; medium-bedded 

(1-3 ft); forms weak ledge —————————

(Line of section crosses fault at this point)

Sandstone, grayish-orange-pink, very fine 

grained, (includes much fine-grained sand), 

very limy; grades into sandy limestone; 

cross-stratified on medium scale; weathers 

gray with laminae etched out; forms ledge —

Concealed slope ———————————————

Limestone, grayish-orange-pink, very sandy, 

cross-stratified on medium to large scale, 

planar-type; weathers to gray surface with 

red laminae and sand grains etched out; 

forms ledge ———————————————

Sandstone, moderate-orange-pink, very fine 

grained (subrounded), calcareous, structureless; forms rounded ledge ——————————

Sandstone, moderate-orange-pink, very fine 

grained (subangular), locally very limy; 

cross-stratified on medium to large scale, 

tabular- and wedge-planar, some crossstrata 20-30 ft long; locally weathers to 

sugary surface; forms cliff with rounded

Feet

17.5

9.0 

11.0

6.5

7.5 

6.0

5.0

2.0

Sandstone, moderate-orange-pink, very fine 

grained, limy, poorly sorted, cross-stratified 

on medium scale, planar-type; weathers to 

brown surface; forms straight ledge —————

Limestone, light-brownish-gray, very sandy, 

poorly sorted, medium-bedded (1-2 ft); 

weathers blue-gray with sand grains etched 

out on surface; forms rounded ledges ————

5.0

5.5

Section 25—Continued 

TWIN SPRINGS CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, main cliff unit— 

Continued

Limestone, pale-reddish-brown with brown 

laminae, sandy (fine- to very fine grained); 

cross-stratified on medium scale, tabularplanar type; weathers to straight, darkbrown face; forms base of main cliff —————

Feet

7.5

Total main cliff unit, Esplande

Sandstone ——————————— 299.0 

(Underlying units measured on west side of

canyon) 

Esplanade Sandstone, basal slope unit:

Concealed slope; locally shows some palereddish-brown, calcareous, crumbly mudSandstone, pale-reddish-brown, very fine 

grained, limy, structureless; weathers to 

sheer face; forms resistant ledge ——————— 5.5 

Concealed slope ————————————————— 16.5 

Sandstone, pale-reddish-brown, very fine 

grained, very calcareous, friable; forms 

rounded boulderlike surface on slope ———— 5.0 

Sandstone, moderate-reddish-orange with 

pale-reddish-brown specks, very fine grained 

(subrounded), limy, thick-bedded (2-4 ft); 

contains abundant lime nodules (0.5-1 in. 

diameter) in upper layers; forms weak cliff — 25.0 

Siltstone, pale-reddish-brown, sandy, calcareous, shaly; contains rain pits; includes a few 

thin (6-24 in.) ledges of thin-bedded siltstone; total forms slope ———————————— 21.0 

Sandstone, pale-reddish-brown, very fine 

grained (subangular), calcareous, friable, 

flat-bedded; contains thin conglomerate 

lenses and scattered limestone pebbles; 

forms weak ledges 1-2 ft thick on slope ——— 7.0 

Sandstone, pale-reddish-brown, very fine 

grained, limy, silty, thin- to medium-bedded 

(1-36 in.); fills channels in underlying rock 

to depth of 35 ft, together with tongues and 

wedges of brownish-gray conglomerate that 

forms rude beds along margins and in bottom of channel; beds fit topography of 

underlying surface, dipping steeply on channel margins; total forms cliff with straight 

face; thickness of channel fill ————————— 0-35.0
466 THE SUPAI GROUP OF GRAND CANYON

Section 25—Continued 

TWIN SPRINGS CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, basal slope unitContinued

Pebbles: dark-gray, pale-gray, and olivegray limestone, pale- and dark-reddishbrown siltstone; subangular to wellrounded; spheroidal to ellipsoidal; 

average diameter 0.25-0.5 in., maximum 

1.5 in.

Matrix: sandstone, fine- to very fine grained; 

moderate-reddish-brown; much calcite cement locally. _

Feet

Total basal slope unit, Esplanade

Sandstone ———————— 85.0-120.0 

Total Esplanade Sandstone ——— 419.0

Unconformity:

Channel approximately 500-700 ft wide, 35 ft 

deep cut through upper two beds of Wescogame slope unit, largely filled with conglomerate. 

Wescogame Formation, slope unit:

Sandstone, pinkish-gray, speckled with palereddish-brown, very fine grained (subangular), calcareous, medium- to thickbedded (2-3 ft); locally cross-stratified on 

small scale, elsewhere massive; weathers to 

rounded surface with brown varnish in 

places; forms resistant ledge ————————— 16.5 

Sandstone, moderate-orange-pink, very fine 

grained, calcareous, cross-stratified on large 

scale (foreset 30-50 ft long); weathers brightreddish-brown; forms weak cliff ——————— 18.0 

Total slope unit, Wescogame

Formation ——————————— 34.5

Wescogame Formation, cliff unit:

Sandstone, pale-reddish-brown with palereddish-brown specks, very fine grained 

(subrounded), calcareous, flat-bedded, thinto medium-bedded (2-24 in.); locally shaly; 

forms weak cliff ———————————————— 28.5

Sandstone, pale-reddish-brown, calcareous, 

friable, thick-bedded; forms upper part of 

bench, concealed below ——————————— 6.5

Sandstone, gray, very fine grained (subSection 25—Continued 

TWIN SPRINGS CANYON—Continued

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued

Sandstone, grayish-red, very fine grained, 

muddy, noncalcareous, silty; locally contains worm borings and small limestone 

nodules; alternating with pale-red, very fine 

grained, limy sandstone; each unit in beds 

0.5-1 ft thick; total forms receding ledges or 

bench —————————————————

Limestone, pale-reddish-brown, very fine 

grained, sandy, prominently cross-stratified 

on medium scale, planar- and compoundtypes (sets 1-3 ft thick); cross-strata etched 

on surface; upper surface contains scattered 

mudstone pebbles, 0.25-1 in. in diameter, 

subangular to subrounded; forms ledge with 

sneer race ———————.______-...._____________

Sandstone, conglomeratic, pale-reddishbrown, mostly very fine grained, limy, 

weakly cross-stratified; contains abundant 

pebbles of dark-gray limestone, a few brown 

siltstone pebbles, and some elongate limestone nodules all in upper part; average 

diameter of pebbles 0.25-0.5 in., maximum 

2 in.; weathers to black varnished surface; 

forms rounded ledge ——————————————_

Feet

9.5

rounded), scattered medium grains, limy, 

thin- to medium-bedded (0.5-2 ft); flatbedded; forms weak cliff ———————

11.5

8.0

13.5

Total cliff unit, Wescogame Formation ————————————— 77.5 

Total Wescogame Formation —— 112.0 

Manakacha Formation, slope unit:

Limestone, grayish-red, muddy (10 percent), 

irregularly bedded; layers 2-3 ft thick; alternating with pale-reddish-brown, sandy, 

limy, structureless siltstone; forms weak, 

rounded ledges, 2-3 ft thick; total forms

Sandstone, grayish-orange-pink with palereddish-brown laminae, very fine grained, 

very limy (44 percent), thin- to mediumbedded (0.5-3 ft); locally cross-stratified on 

small to medium scale; contains a parting of 

reddish-brown shaly mudstone 12 ft above 

base; forms prominent cliff —————————— 41.0

Sandstone, pale-reddish-brown, very fine 

grained, limy (31 percent), thin-bedded 

(2-12 in.) to shaly; forms bench ——————— 7.5 

Total slope unit, Manakacha

Formation ——————————— 64.5
MEASURED STRATIGRAPHIC SECTIONS 467

Section 25—Continued 

TWIN SPRINGS CANYON-Continued

Section 25—Continued 

TWIN SPRINGS CANYON-Continued

ledge

Feet Feet

Supai Group—Continued

Manakacha Formation, cliff unit:

Sandstone, pale-reddish-brown, very fine 

grained, limy (25 percent); weakly 

developed, medium-scale cross-stratification; laminae locally horizontal; units 0.5-3 

ft thick; locally weathers with black varnish; 

forms prominent cliff ————————————— 38.5

Limestone, pale-reddish-brown, very sandy 

(fine-grained); cross-stratified on medium to 

large scale, planar- and compound-types; 

contains fusulinds (Eoschubertella); forms

14.5

Sandstone, pale-reddish-brown, very fine 

grained, limy, flat-bedded, thin- to mediumbedded (0.5-3 ft); weathers dark-brown; 

forms bench or recess ————————————— 6.0

Sandstone, pale-reddish-brown, very fine 

grained, very limy (49 percent), crossstratified on medium to large scale; planarand compound-types; weathers brown to 

pink with cross-strata prominently etched on 

surface; forms cliff ——————————————— 40.0

Limestone, light-brownish-gray, silty (25 percent), aphanitic; contains bands of jasper 

along bedding planes and also crosscutting 

beds; forms part of cliff ———————————— 6.0

Limestone, dark-gray; concretionary with 

dark-reddish-brown siltstone matrix; forms 

recess —————————————————————— 3.5

Siltstone, light-brownish-gray, limy (42 percent), hard; cross-stratified on medium 

scale; weathers to black vertical face; forms 

base of main cliff ———————————————— 6.0

Sandstone, light-brownish-gray, very fine 

grained, calcareous, friable, gnarly bedded; 

forms slope ——————————————————— 5.5

Limestone, olive-gray, aphanitic, mediumbedded (6-24 in.); contains bands of jasper; 

forms weak ledges ——————————————— 4.0

Concealed slope; contains nodular limestone 

with shaly siltstone at top ——————————— 10.0

Limestone, blue-gray, silty, flat-bedded; contains bands of jasper; forms receding ledges, 

1-2 ft thick —————————————— 5.5

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Limestone, medium-light-gray, very fine 

grained, sandy (30 percent), cross-laminated 

on small to medium scale; contains bands of 

jasper; weathers to black surface with 

laminae prominently etched out; forms uppermost of two prominent ledges —————— 8.0

Limestone, dark-brownish-gray, nodular,

silty; forms recess between prominent ledges - 11.0

Siltstone, medium-light-gray and light-brownish-gray, aphanitic, very limy (45 percent); 

contains very irregular masses of chert and 

jasper, which weather dark-brown; forms 

lower of two prominent ledges ———————— 5.5

Limestone, light-brownish-gray, nodular, 

silty (35 percent); forms bench and recess —— 2.5

Limestone, medium-gray, silty (23 percent), 

aphanitic; contains bands of jasper; forms 

resistant ledge ————————————————— 2.0

Limestone, pale-reddish-brown, very fine 

grained, silty (37 percent), nodular; contains 

lenses of jasper and crumbly, brown siltstone; forms slope, partly concealed, and 

recess —————————————————————— 5.5

Siltstone, light-brownish-gray, limy (38 percent), fine-grained, hard; weathers to black 

face; forms resistant ledge ——————————— 4.5 

Total cliff unit, Manakacha Formation ————————— 178.5

Total Manakacha Formation —— 243.0

Watahomigi Formation:

Concealed slope ————————————————— 49.5 

Limestone, medium-gray, aphanitic; contains 

very irregular masses of jasper; weathers to 

rough surface; forms resistant ledge ————— 3.5 

Concealed slope ————————————————— 4.5 

Limestone, purple, speckled with red, finegrained, cross-stratified on medium scale; 

contains jasper; forms receding ledges ———— 8.0 

Concealed slope ————————————————— 4.0 

Limestone, light-gray, aphanitic with scattered coarse grains in lower part, thickbedded (3-8 ft); contains brachiopod outlines and scattered concretions of jasper; 

weathers to rough, pitted surface; forms upper part of cliff ————————————————— 36.0
468 THE SUPAI GROUP OF GRAND CANYON

Section 25—Continued 

TWIN SPRINGS CANYON-Continued

Supai Group—Continued 

Watahomigi Formation—Continued 

Limestone, very light gray, very fine grained, 

silty (40 percent), laminated and crosslaminated on small scale; contains abundant 

beds of chert, which weather black, giving

unit dark conspicuous face; forms part of 

cliff ___—__—_______________—___________—_____

Limestone, pinkish-gray, fine- to mediumgrained, medium- to thick-bedded (2-6 ft); 

contains scattered bands of jasper; weathers 

to rough, dark-gray surface; forms base of 

prominent cliff, which separates lower 

Watahomigi in about middle ———————

Concealed slope ——————————————

Limestone, medium-gray, crystalline to aphanitic, thin-bedded (6-24 in.); contains 

numerous brachiopods (Composita sp.); 

contains scattered bands of nodular jasper; 

forms ledge ———————————————

Mudstone, pale-reddish-brown, calcareous,

Section 25—Continued 

TWIN SPRINGS CANYON—Continued

Feet Feet

6.5

21.0

13.0

16.0

very brittle; forms slope —————————— 11.0

Limestone, medium-gray, fine-grained, thinbedded (2-4 in.); contains numerous brachiopods (Derbyia, Spirifer, Composita}; 

forms weak ledge ———————————————— 0.5

Limestone, medium-gray, muddy, shaly;

weathers reddish-brown; forms slope ———— 5.5

Limestone, medium-gray, very fine grained, 

thin-bedded (0.5-12 in.); contains dark siliceous stringers ————————————————— 3.0

Claystone, light-brownish-gray, shaly, very 

calcareous, very brittle; forms slope, partly 

concealed ———————————————————— 10.5

Conglomerate, very pale orange and palereddish-brown, forms ledge—————————— 1.0 

Pebbles: gray limestone and reddish-brown 

siltstone; average diameter 0.5-1 in.; 

rounded. 

Matrix: buff siltstone.

Siltstone, pale-reddish-brown, silty, calcareous, fissility weakly developed; forms slope — 2.0

Mudstone, grayish-red-brown, noncalcareous, 

brittle, structureless; forms slope —————— 3.5 

Total Watahomigi Formation — 199.0 

Total Supai Group ———————— 973.0 

Contact:

Unconformity assumed; surface poorly exposed.

Redwall Limestone:

Horseshoe Mesa Member: 

Limestone, yellowish-gray, aphanitic, thinbedded (1-2 ft); weathers to rough surface; 

forms receding ledges ————————— Not measured

Section 26 

GUANO CAVE

[Measured at tram to Guano Cave (also called Bat Cave) on south side of 

Colorado River]

Surface of recent erosion. 

Pakoon Limestone, cliff unit:

Sandstone, moderate-reddish-brown and gray 

in irregular bands, very fine grained, 

medium-bedded (1-3 ft); contains smallscale cross-stratification; hard; forms reSandstone, pale-red, very fine grained, limy 

(30 percent), medium-bedded (1-2 ft); contains parting zones of crumbly, 

red-brown, very fine grained sandstone; 

similar to underlying sandstone bed but 

forms slope with steplike ledges —————— 

Sandstone, grayish-pink, aphanitic, limy (35 

percent), thick-bedded (2-4 ft), massive, 

weakly cross-stratified locally; weathers 

reddish-brown or with black varnish; forms 

rounded, receding ledges ——————————

Pakoon

4.0

21.0

27.5

Cliff unit, part, 

Limestone ——————————— 52.5 +

Pakoon Limestone, slope unit:

Sandstone, moderate-reddish-brown, very fine 

grained, structureless; weathers to rounded 

surface; forms weak ledge or slope ————— 3.0

Sandstone, moderate-reddish-orange, very fine 

grained, calcareous (30 percent), thickbedded (2-3 ft); contains wedge-planar 

cross-stratification, medium-scale (5-10 ft 

long); contains abundant worm borings 

(diameter 0.25 in.); forms series of receding 

ledges————————————————— 11.0

Sandstone, pale-reddish-brown, aphanitic, 

very limy (44 percent), very resistant, 

medium-to thick-bedded (1-8 ft); forms 

resistant cliff —————————————————— 14.5
MEASURED STRATIGRAPHIC SECTIONS 469

Section 26—Continued 

GUANO CAVE-Continued

Feet

Pakoon Limestone, slope unit—Continued

Claystone, pale-reddish-brown, shaly,

crumbly; forms bench ————————————— 2.0 

Limestone, pale-reddish-brown, aphanitic, 

silty, (10 percent), platy, thin- to mediumbedded (1-3 ft); contains tabular-planar 

cross-stratification; brown, silty laminae 

etched on surface; forms ledge ———————— 12.0 

Sandstone, grayish-orange-pink, very fine 

grained, friable, structureless; weathers to 

gray, rounded surface; forms ledge —————— 4.0 

Limestone, pale-reddish-brown, aphanitic, 

very sandy (33 percent), platy, hard, 

medium-bedded (1-3 ft); contains planar 

cross-stratification; forms ledge ——————— 16.5 

Conglomerate, pale-reddish-brown, forms part 

of ledge ————————————————————— 2.0 

Gravel: limestone, gray, brown and white, 

and siltstone, pink and gray; rounded to 

subrounded; diameter maximum 2 in., 

average 0.5-1 in.; contains local concentrations of a large pelecypod. ____ 

Total slope unit, Pakoon Limestone —————————————— 65.0 

Total Pakoon Limestone ———— 117.5 +

Supai Group: 

Wescogame Formation, cliff and slope units undifferentiated:

Limestone, light-brownish-gray, aphanitic, 

sandy (18 percent), resistant, mediumbedded (1-3 ft); contains flat to irregular 

laminae in part, planar cross-strata in part; 

brown, silty laminae etched on surface; contains abundant pelecypods in thin zone 5 ft 

above base; forms ledge ———————————— 13.0

Sandstone, pinkish-gray, very fine grained 

(subrounded to subangular), mediumbedded (1-3 ft), structureless; weathers to 

brown, rounded surface; forms base of cliff — 9.0

Sandstone, pale-reddish-brown, very fine 

grained, limy (39 percent), friable, thinbedded (6-12 in.); partly flat-bedded, partly 

cross-bedded, planar-type; weathers to 

rounded surface; forms prominent bench —— 21.0

Limestone, grayish-pink, aphanitic, sandy 

(14 percent); contains wedge-planar crossstratification on medium scale; brown, silty 

laminae etched on surface; forms weak ledge 11.0

Section 26—Continued 

GUANO CAVE—Continued

Supai Group—Continued 

Wescogame Formation, cliff slope units 

undifferentiated—Continued 

Sandstone, pale-reddish-brown, very fine 

grained, very limy (35 percent), flat-bedded, 

medium-bedded (1-2 ft); weathers to weak, 

rounded ledge or bench ———————————— 

Limestone, pale-reddish-purple, silty (17 percent), aphanitic with siltstone partings, 

hard, platy; contains wedge-planar crossstratification on medium to large scale; 

brown, silty laminae etched on surface; 

forms slope and weak ledges (3-4 ft thick) — 

Conglomerate, pale-gray, ledge-forming ———— 

Gravel: limestone, reddish-brown, white, 

gray; and chert, white, buff; and siltstone, 

gray; diameter maximum 2 in., average 

0.25-0.5 in.; mostly subrounded to 

rounded. 

Matrix: coarse-grained limestone.

Total Wescogame Formation ——

Feet

12.0

18.5 

2.0

86.5

Manakacha Formation, slope unit:

Sandstone, grayish-orange-pink to palereddish-brown, very fine grained, thin, 

platy, limy, cross-stratified, medium-scale 

(5-10 ft long, wedge-planar); forms series of 

weak ledges —————————————————— 26.0

Sandstone, grayish-orange-pink, very fine 

grained, calcareous (30 percent), crumbly, 

weathers pink to white, platy (beds 0.25-1 

in.); forms slope ———————————————— 14.0

Sandstone, grayish-orange-pink, very fine 

grained, very silty (±50 percent), friable, 

calcareous, like overlying bed but thin- to 

medium-bedded (0.5-2 ft); forms series of 

receding ledges or slopes ——————————— 9.0 

Total slope unit, Manakacha

Formation ——————————— 49.0

Manakacha Formation, cliff unit:

Sandstone, pale-orange-pink, very fine grained, 

hard, calcareous (30 percent), thick-bedded 

(2-6 ft); planar cross-stratified throughout; 

forms cliff ———————————————————— 57.0

Limestone, olive-gray, very fine grained, thickbedded (3-4 ft); contains jasper concretions; 

weathers gray; forms part of cliff —————— 7.0
470 THE SUPAI GROUP OF GRAND CANYON

Section 26—Continued 

GUANO CAVE-Continued

Feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Sandstone, very pale orange, very fine grained, 

hard, limy (40 percent), thick-bedded (2-6 

ft); planar cross-stratified on medium to 

large scale throughout; forms major cliff —— 28.0 

Limestone, olive-gray, very fine grained, sandy 

(45 percent), cross-stratified on medium 

scale; locally contains chert concretions; 

weathers dark-gray; forms ledge ——————— 6.5 

Conglomerate, possible marker bed; deposited 

on erosion surface and in channels cut into 

underlying limestone ————————————— 2.0 

Matrix: very fine grained, olive-gray limestone.

Pebbles: medium-light-gray and olive-gray 

chert and red jasper, angular, mostly 

0.13-0.25 in. in diameter, maximum 

diameter 1 in.

Limestone, medium-light-gray, very fine 

grained with scattered large crystals, resistant, medium-bedded (1-3 ft), silty (30 

percent); locally cross-stratified; includes 

thin partings or recesses of red, shaly siltstone; contains abundant lenses and irregular beds of jasper; forms series of ledges ——— 60.5 

Total cliff unit, Manakacha Formation ————————————— 161.0

Section 26—Continued 

GUANO CAVE—Continued

Supai Group—Continued 

Watahomigi Formation, upper slope unit— 

Continued

Limestone, medium-light-gray, fine-grained, 

thin-bedded; base contains abundant fusulinids(?), crinoids, brachiopods (Composite); 

forms weak ledges 6-12 in. thick; alternates 

with purple, shaly mudstone, locally contains 

limy pellets, 0.25-0.5 in. in diameter; forms 

slopes 2-4 ft thick; total forms slope —————

Total Manakacha Formation —— 210.0

Watahomigi Formation, upper slope unit:

Siltstone, pale-reddish-brown to grayish-redbrown to grayish-green, shaly; contains flattened, silty, limestone balls scattered 

throughout; forms slope ——————————

Siltstone, moderate-reddish-brown, very

sandy, irregularly bedded; makes conspicuous marker; forms slope —————————

Limestone, grayish-reddish-purple, very fine 

grained, silty (32 percent); concretionary; 

forms rounded ledge ———————————

Siltstone, pale-reddish-brown, limy (35 percent), shaly; includes several ledges of resistant siltstone containing limestone concretions; contains cusp-type ripple marks;

5.5

2.5

2.0

Feet

18.5

16.5

Limestone, light-gray, conspicuously oolitic

(1-2 mm diameters); forms weak ledge ——— 2.5

Limestone, magnesian, medium-light-gray, 

with light-olive-gray spots and streaks, very 

fine grained; contains abundant thin layers 

and lenses of jasper; forms series of small 

ledges (1-2 ft thick) separated by concealed

Conglomerate, locally developed; contains 

intraformational limestone granules and 

pebbles (maximum 4 mm); and mediumlight-gray limestone with light-olive-gray 

spots, very fine grained, thin-bedded (2-8 

in.); locally contains abundant crinoids; 

forms rounded ledges ————————————— 6.0 

Total upper slope unit, Watahomigi Formation ——————— 64.5

Watahomigi Formation, middle cliff and lower

slope units:

Limestone, light-gray, very fine grained; thickbedded (1-5 ft); contains lenses and concretions of jasper; forms small cliff ——--—--

Limestone, pale-red-purple with gray blotches, 

fine-grained with scattered larger crystals, 

granular; forms rounded ledge —

Limestone, olive-gray, very fine grained, thinbedded (6-30 in.); forms series of ledges or

Limestone, light-olive-gray, aphanitic to very 

fine grained; contains abundant conspicuous 

white chert bands composing as much as 80 

percent of the rock; individual layers commonly 0.25-0.5 in. thick; forms ledge at top 

of cliff -----——————-—.—..——______ 2.0

10.0

——~—— 2.5

15.5
MEASURED STRATIGRAPHIC SECTIONS 471

Section 26—Continued 

GUANO CAVE-Continued

Feet Feet

Supai Group—Continued 

Watahomigi Formation, middle cliff and lower

slope units—Continued

Dolostone, very pale gray, with pale-reddishbrown bands, medium-grained, hard, crystalline, medium-bedded (1-2 ft); shows 

lamination with alternate layers leached on 

surface; rests with sharp but irregular contact on underlying unit; weathers dark-gray; 

forms cliff ———————————————————— 28.5

Limestone, olive-gray, fine-grained, forms 

one massive bed; weathers gray; forms resistant cliff ——————————————————— 11.0

Limestone, light-olive-gray, aphanitic, thinbedded (2-6 in.); forms recess ———————— 2.5

Limestone, light-olive-gray with pale-brown, 

fine-grained, hard, very thick bedded (5-15 

ft); grades upward into pale-olive-gray and 

pinkish-gray, medium-grained, sandy limestone; contains brachiopods and ostracodes 

(?); weathers to rough gray surface; forms 

sheer cliff ———————————————————— 32.0

Limestone, grayish-pink to light-gray, aphanitic, thick-bedded (2-3 ft); contains many 

small (0.25-0.5 in.) orange to black chert 

nodules; forms ledges ————————————— 7.0

Limestone, light-brownish-gray, mediumgrained, locally crystalline; weathers darkgray; forms ledge ———————————————— 4.0

Concealed slope ————————————————— 5.5

Limestone, medium-light-gray, aphanitic, with 

scattered crystals as much as 0.6 mm in 

diameter, thin-bedded (0.5-1 ft); contains 

scattered fragments of chert 0.25-0.5 in. in 

diameter; forms receding ledges ——————— 5.5

Limestone, pale-grayish-pink, coarse-grained,

thick-bedded (2-4 ft); forms resistant ledge — 9.0

Limestone, pinkish-gray, fine-grained, thinbedded (1 ft); weathers to rough surface; 

forms receding ledges ————————————— 3.0

Limestone, grayish-pink, very fine grained; 

contains light-brownish-gray and olive-gray 

pellets and fragments of intraformational 

origin, mostly 2-4 mm in diameter, maximum diameter 1 in.; forms ledge —————— 3.0

Sandstone, pale-reddish-brown, very fine 

grained, soft; forms slope, largely concealed 11.0

5.0

3.0

2.0

162.0

Section 26—Continued 

GUANO CAVE-Continued

Supai Group—Continued 

Watahomigi Formation, middle cliff and lower 

slope units—Continued

Siltstone, pale-pinkish-gray, structureless, 

hard, quartzitic; weathers to dark-brown 

varnished surface; forms ledge ——————

Limestone, light-olive-gray, very fine grained, 

very sandy, hard, medium-bedded (1-2 ft); 

contains abundant worm borings; forms resistant ledge ——————————————————

Mudstone, moderate-reddish-brown, crumbly, 

forms slope; largely concealed ———————— 

Total middle cliff and lower 

slope units, Watahomigi Formation —————————————____ 

Total Watahomigi Formation — 226.5 

Total Supai Group and Pakoon

Limestone ——————————— 640.5 +

Unconformity:

Not recognized at this locality. 

Redwall Limestone:

Horseshoe Mesa Member: 

Limestone, yellowish-gray, aphanitic, mediumbedded (1-2 ft); weathers to rough, pitted 

surface; forms receding ledge ————— Not measured

Section 27 

SNAP CANYON

[Grand Wash Cliffs; measured in Snap Canyon about 5 miles south of 

Grand Gulch Mine]

Feet

Hermit Shale:

Sandstone, moderate-reddish-orange, very 

fine grained; thick-bedded (1-3 ft); alternating with pale-reddish-brown, shaly, 

slope-forming mudstone; total forms slope 

with ledges (40 percent:60 percent) ————— 62.5 

Contact: Surface of unconformity not noted here. 

Supai Group:

Esplanade Sandstone, upper cliff-slope unit: 

Sandstone, very pale orange to moderatereddish-orange, very fine grained (subangular), calcareous; cross-stratified on 

medium scale; forms resistant cap rock ——— 3.0
472 THE SUPAI GROUP OF GRAND CANYON

Section 27—Continued 

SNAP CANYON-Continued

Supai Group—Continued

Esplanade Sandstone, upper cliff-slope unitContinued

Siltstone, pale-reddish-brown, muddy; shaly 

near base, massive above; forms slope and

Sandstone, moderate-reddish-orange, very 

fine grained (subangular), massive; locally 

cross-stratified; forms very resistant ledge —-

Sandstone, pale-reddish-brown, very fine 

grained, very silty, resistant, ledge-forming, 

thin-bedded (1-2 ft); alternating with palereddish-brown, silty, very thin bedded (1-2 

in.) mudstone; slope-forming; contains 

shrinkage cracks and many worm borings; 

total forms slopes and ledges ————————

Sandstone, moderate-reddish-orange (local 

white layers in middle); fine- to very fine 

grained (subangular); cross-stratified on 

medium to large scale; cliff-forming —————

Mudstone, pale-reddish-brown, silty, thickbedded (2-4 ft); forms rounded ledge ————

Siltstone, pale-reddish-brown; includes some 

very fine grained, angular sand; shaly to 

thin-bedded (2-12 in.), slope-forming ———

Sandstone, moderate-reddish-orange, calcareous, fine- to very fine grained; resembles 

basal bed; forms weak cliff ————————

Mudstone, pale-reddish-brown, silty, thinbedded (2-6 in.), slope-forming —————

Sandstone, moderate-reddish-orange, very fine 

grained (subangular), calcareous, friable; 

cross-stratified, medium-scale; forms weak, 

rounded cliff ———————————————

Sandstone, moderate-reddish-orange, very 

fine grained (subangular), calcareous, thinbedded (1-2 ft), friable; forms slope and 

weak cliff with prominent bench at top ——

Sandstone, moderate-reddish-orange, very fine 

grained (angular); massive; forms cap rock —

Sandstone, moderate-orange-pink, very fine 

grained, locally cross-stratified, weathers to

Sandstone, moderate-reddish-orange, very fine 

grained (subrounded), silty, platy, slopeforming ———————————————————

Sandstone, moderate-orange-pink, very fine 

grained (subangular), calcareous, thinbedded (1-2 ft), friable; forms rounded 

ledges —————————————————————

Section 27—Continued 

SNAP CANYON—Continued

Feet

Supai Group—Continued

Esplanade Sandstone, upper cliff-slope unitContinued

Siltstone, grayish-red, thin-bedded (2-6 in.) to 

shaly; alternating with grayish-orange-pink, 

13.5 very fine grained (subangular), calcareous, 

thin-bedded (2-12 in.) sandstone; moderately resistant; forms weak ledges ——————— 10.0 

7.0 Total upper cliff-slope unit, Esplanade Sandstone —————— 299.0 

Total Esplanade Sandstone ——— 299.0

Pakoon Limestone, cliff unit:

51.5 Limestone, light-brownish-gray, fine-grained,

very thin bedded (0.5-2 in.), platy, sandy

(10 percent); contains ooids (2-4 mm);

weathers to smooth, even surface with

71.5 grayish-red laminae etched out; contains

jasper concretions ———————————————— 3.5

9.5 Limestone, light-olive-gray, aphanitic, very

thin bedded (0.5-1 in.); contains many

brown chert concretions near top; (colonial

14.0 corals at 21 ft up; hexacorals and Favosites

at top); forms receding ledges ———————— 30.5 

Limestone, dolomitic, and limestone, light7.5 olive-gray, very coarse grained, thin- to 

thick-bedded (1-4 ft); fossiliferous (hex3.0 acorals at 8 ft and above; many crinoids at 

16 ft); weathers to series of rough, gray to 

brown ledges —————————————————— 38.5 

Sandstone, grayish-orange, very fine grained 

23.0 with scattered fine grains (angular to subangular), calcareous; thick-bedded (2-4 ft); 

weathers to dark-brown surface; cliffforming ————————————————————— 5.5 

41.5 Limestone-magnesian, pale-reddish-brown, 

aphanitic, very sandy, cross-stratified on 

4.0 large scale, platy; sandy laminae etched on

surface; forms weak cliff ———————————— 16.0 

Limestone, light-brownish-gray, medium16.5 grained, sandy; forms resistant cliff with

rough surface —————————————————— 9.5 

Dolostone, very pinkish gray, aphanitic, thin7.0 bedded (0.5-2 ft); laminated upper part;

weathers cream-colored; forms recess ———— 13.0 

Dolostone, calcitic, pale-yellowish-brown, 

aphanitic, very thick bedded (5 ft); weathers 

16.5 rough, gray surface ——————————————— 5.0
MEASURED STRATIGRAPHIC SECTIONS 473

Section 27—Continued 

SNAP CANYON-Continued

Pakoon Limestone, cliff unit—Continued

Limestone-dolomitic, olive-gray to pinkishgray, fine-grained, very fossiliferous 

(fusulinids, crinoids, brachiopod fragments; 

large hexacoral colonies at top), thin-bedded 

(1-2 ft); forms weak cliff ———————-———

Limestone, light-gray, medium-grained, thinbedded (1-2 ft), cliff-forming; weathers to 

rough, black surface ————————————

Limestone, olive-gray, aphanitic, thick-bedded 

(2-4 ft); very fossiliferous near base (hexacorals, horn corals, crinoids, echinoid 

spines); weathers to yellow-brown cliff ——— 

Total cliff unit, Pakoon Limestone —————————————

Pakoon Limestone, slope unit:

Limestone, light-brownish-gray, mediumgrained; thin-bedded (2-6 in.) at base, irregularly bedded above; contains chert beds 

in middle; very fossiliferous ybryozoans, 

crinoids, echinoid spines, brachiopods); 

forms weak cliff and slope ——————————

Limestone, light-gray to grayish-red, mediumgrained, very sandy (25 percent angular, 

very fine grained), thin- to very thin bedded 

(0.5-6 in.), weakly-laminated; includes some 

grayish-orange-pink sandstone; weathers to 

slope or ledge ————————————————

Conglomerate, light-olive-gray; forms 

rounded ledge —————————————

Matrix: light-olive-gray limestone, coarsegrained. 

Gravel: limestone, dark-gray to olive-gray,

rounded; mostly 0.25-1 in. diameters.

Total slope unit, Pakoon Limesronc ————————••———————————-"—

Total Pakoon Limestone ——— 

Supai Group: 

Wescogame Formation, slope unit:

Sandstone, pale-reddish-brown, very fine 

grained (subrounded) and pale-red, fine- to 

very fine grained, shaly, slope-forming sandstone; contains three beds of resistant, ledgeforming, light-brownish-gray, sandy limestone, each 2-3 ft thick —————————

Limestone, pale-red, aphanitic, sandy, crossstratified (medium- to large-scale), thickbedded (1-4 ft); sandy laminae etched prominently; forms cliff with pink to dark-brown

Feet

21.5

5.5

28.5

177.0

13.0

8.5 

1.0

199.5

22 . 0

——-.-._-,—— _._.,_..._,.. 1 A.y,\J 0 C\

Section 27—Continued 

SNAP CANYON-Continued

Feet

Supai Group—Continued 

Wescogame Formation, slope unit—Continued 

Siltstone, grayish-red, flat-bedded, friable,

slope-forming —————————————————— 14.0 

Total slope unit, Wescogame

Formation ——————————— 55.0

Wescogame Formation, cliff unit:

Sandstone, pale-reddish-brown, very fine 

grained (rounded), limy (30 percent); forms 

cliff _______________———_——- 23.0

Sandstone, pale-red, calcareous (28 percent); 

like siltstone bed in slope unit above; contains some very fine grained sand —————— 12.0 

Limestone-magnesian, moderate-orange-red, 

insoluble (43 percent); like limestone bed in 

slope unit above; contains large shrinkage 

polygons near base —————————————— 39.0 

Sandstone, moderate-reddish-orange, silty,

platy; forms bench ——————————————— 3.0 

Limestone, light-brownish-gray, coarsegrained, thick-bedded (2-5 ft); weathers to 

rough surface; forms weak ledge ——————— 21.0 

Conglomerate, pale-reddish-brown; forms 

rounded ledge ————————————————— 3.0 

Matrix: pale-reddish-brown limestone. 

Gravel: rounded limestone pebbles (2-6 in. 

diameter). ———— 

Total cliff unit, Wescogame Formation —~————————— 101.0

Total Wescogame Formation —— 156.0

Unconformity:

Erosion surface. Channels cut to depth of 34

ft in limestone. 

Manakacha Formation, slope unit:

Limestone, pale-reddish-brown, aphantic, sandy 

(22 percent); cross-stratified throughout 

(medium-scale, lower two-thirds; large-scale 

above); forms major cliff, rounded lower 

part, angular above; contains two beds of 

flat, rubbly lime-stone with calcareous concretions at 27 ft up; fossiliferous (straight 

cephalopods, many bellerophons); contains 

unoriented slumped block (2 ft X 3 in.) of 

cross-stratified limestone incorporated at 

33 ft up —————————————————————— 60.5
474 THE SUPAI GROUP OF GRAND CANYON

Section 27—Continued 

SNAP CANYON-Continued

Feet

Supai Group—Continued 

Manakacha Formation, slope unit—Continued 

Sandstone, pale-red, very calcareous (44 

percent), very fine grained, weakly crossstratified; forms rounded ledges at base of 

main cliff ———————————————————— 6.5 

Total slope unit, Manakacha

Formation ——————————— 67.0 

Manakacha Formation, cliff unit:

Limestone, light-brownish-gray (near base), 

pale-reddish-brown (above), aphanitic; very 

sandy; cross-stratified on medium scale; 

contains near base bed of irregularly concentric layers (10-20 in. diameters), probably 

stromatolitic; contains at 33 ft up many 

elliptical, jasper lenses (diameters to 3 ft) —— 126.5 

Limestone, light-gray to light-olive-gray, 

aphanitic, thick-bedded (2-3 ft); contains 

beds of spherical, gray concretions with concentric layers, possibly stromatolitic; 

weathers to rough, gray ledge; forms marker

Limestone, light-gray, sandy (32 percent), 

grades upward into grayish-orange-pink, 

very fine grained (subangular), calcareous 

sandstone; cross-stratified on medium scale; 

flat-bedded at top; contains fusulinids 

(Eoschubertella) ——————————————

Sandstone, pale-reddish-brown, very fine 

grained, very calcareous (45 percent), flatbedded; contains thin jasper layers at top; 

fossiliferous in jasper layers; forms cliff ———

Limestone, light-brownish-gray to palereddish-brown, aphanitic, very sandy (20 

percent); cross-stratified on medium scale; 

laminae etched on surface; like 44-ft 

limestone above ————————————————

Sandstone, medium-gray to brownish-gray, 

very fine grained, very limy (42 percent), 

very thick bedded (3-8 ft); contains flat, 

laminated beds with prominent concretionary layers (0.5-2 in. thick) in lower part; 

cross-stratification, medium- to large-scale 

in upper part; contains some jasper lenses

<*J\J ^0-40 *±\J ff 1 IInner 1U1 1^_____________ ——— ___ —————— _——————

Limestone, pale-reddish-brown to very light 

gray, very fine grained, silty (25 percent), 

thick-bedded (2-3 ft), laminated; contains 

spherical, white chert concretions (1-6 in.) in 

upper part ; cliff -forming ————————————

44.0

11.0

8.5

1Q1. 7 .

11 . 0

Section 27—Continued 

SNAP CANYON—Continued

Feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Limestone, light-brownish-gray to lightolive-gray, fine-grained; contains many 

jasper lenses; forms base of main cliff ———— 2.0 

Total cliff unit, Manakacha Formation —————————————229.0 

Total Manakacha Formation —— 296.0

Watahomigi Formation:

Concealed largely, slope probably mostly 

silty mudstone; contains ledge (6 in.) of very 

fossiliferous, coarse-grained, medium-gray 

limestone at 10 ft up; contains beds (1 ft) of 

grayish-red siltstone and moderate-reddishbrown mudstone about 28 ft up ——————— 55.0

Limestone, light-brownish-gray, fine-grained; 

weathers to ledge with rough surface containing siliceous, reticulate ridges —————— 3.0

Concealed, forms slope ————————————— 5.5

Limestone, light-brownish-gray, coarsegrained, thick-bedded (2-3 ft), very fossiliferous (brachiopods); forms ledge ————— 5.0

Limestone, light-brownish-gray to mediumlight-gray, coarse-grained, thin-bedded (1 

ft); includes near base thick (10 in.) jasper 

bed; very fossiliferous (brachiopods, pelecypods, others); forms series of weak, 

rounded ledges ————————————————— 26.0

Limestone, light-olive-gray to light-brownishgray, mostly aphanitic, thin- to thickbedded (1-4 ft); contains many thin, jasper 

layers in lower part, lenses above; includes 

coarse-grained, accretal-grained limestone 

with fossils (brachiopod molds) at 44 ft up; 

forms top of cliff ———————————————— 55.0

Limestone, light-olive-gray, very thick bedded 

(4-8 ft); forms upper part of cliff; locally is 

unconformable with underlying unit, which 

thickens and thins laterally; weathers lightgray, in contrast to black surface below ——— 22.0

Dolostone, pinkish-gray, coarse- to very 

coarse grained, thick-bedded (2-4 ft); contains stylolites, jasper lenses and possible 

stromatolite structures at 33 ft; has cavernous texture, possibly reefoid, at 40 ft; fossiliferous (many colonial corals) at 55 ft 

above base; forms cliff ————————————— 56.0

Limestone, light-brownish-gray, aphanitic,

thin-bedded (1-3 ft); forms massive cliff —— 12.0
MEASURED STRATIGRAPHIC SECTIONS 475

Section 27—Continued 

SNAP CANYON-Continued

Feet

Supai Group—Continued 

Watahomigi Formation—Continued

Limestone, grayish-red and light-olive-gray, 

fine-grained; contains fossil fragments; fills 

pockets, but upper beds are continuous 

across surface of relief; contains thin 

parting-beds (2-4 in.) of red mudstone; 

weathers to yellowish-brown ———————— 2.0-5.0 

Zone of weathered limestone beds and reddishbrown, silty clay with very irregular, gnarly 

structure, overlain by 2-3 ft of reddishbrown mudstone containing rounded, 

weathered limestone pebbles (2-4 in.) ———— 3.0 

Total Watahomigi Formation — 247.5 

Total Supai Group and Pakoon

Limestone ———————————1198.0 

Unconformity:

Surface of erosion is undulating; depressions, 

2-3 ft deep, and small mounds occur within 

20-ft exposure. Basal unit in Watahomigi of 

adjacent sections is missing here; probably 

caused by topographic high on Redwall. 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, yellowish-gray to dark-olive-gray, 

aphanitic; forms receding ledges; contains 

many cavities and channels filled with 

laminated, reddish-brown siltstone.

Section 28 

PIGEON WASH

[On north side of Pigeon Wash, Grand Wash Cliffs]

Feet

Recent erosion surface.

Pakoon Limestone, cliff unit:

Limestone, magnesian, light-brownish-gray, 

very fine grained, scattered medium grains; 

medium-bedded (1-3 ft); upper 16-17 ft contain abundant crinoid and echinoid fragments; also contains colonial corals, productids; forms rounded receding ledges ——— 38.5 

Limestone, grayish-orange-pink; contains 40 

percent very fine grained quartz and scattered pebbles of quartz, sugary; abundant 

very small bioclasts; weathers to weak, 

rounded ledges ———————————————— 2.5 

Limestone, light-brownish-gray, very fine 

grained; scattered fine grains; weathers to 

sandy surface; forms ledge —————————— 2.0

Section 28—Continued 

PIGEON WASH—Continued

Pakoon Limestone, cliff unit—Continued

Concealed slope ————————————————

Dolostone, calcitic, grayish-orange-pink, finegrained, thin-bedded (6-12 in.); weathers 

buff; forms receding ledges on slope —————

Dolostone, calcitic, pale-yellowish-brown, 

very fine grained; medium-to thick-bedded 

(1-3 ft); contains many vugs and fossil 

molds filled with calcite; contains abundant 

corals (conspicuous zone near base); and 

crinoid joints, which weather brown; forms 

receding ledge with rough, pitted surface; 

weathers very pale orange ——

Limestone, magnesian, light-brownish-gray; 

aphanitic; similar to underlying limestone 

bed (except for color); contains bryozoans, 

fusulinids, brachiopods, abundant crinoid 

joints; weathers light-gray; forms receding 

ledge ————————————————————

Limestone, grayish-orange-pink, aphanitic, 

thin- to medium-bedded (6-30 in.); weathers 

to creamy-white surface; forms series of receding ledges with pitted surfaces ——————

Dolostone, grayish-orange-pink, very fine 

grained; includes scattered coarse grains; 

contains abundant geodes and fossil casts, 

partly filled with calcite; weathers to rough 

surface; forms prominent, resistant ledge ——

Dolostone, pale-reddish-brown, very fine 

grained, silty (23 percent), medium-bedded 

(2-3 ft); contains abundant sea urchin 

spines; weathers to cream color; forms receding ledges ——————————————————

Dolostone, calcitic, pale-reddish-brown, very 

silty (46 percent), thin-bedded (1-6 in.); contains large brachiopods; forms slope —————

Limestone, dolomitic, grayish-orange-pink, 

aphanitic with scattered medium grains; 

medium-bedded (1-2 ft); contains very irregularly layered brown chert; contains 

brachiopods and abundant crinoids, silicified at surface; forms cliff continuous with 

underlying unit ——————————

Limestone, light-brownish-gray, aphanitic, 

with scattered fine grains; very thick bedded 

(2-3 ft); contains abundant silicified fossils 

(brachiopods, sea urchin spines, crinoids, 

fusulinids, bryozoans); forms prominent resistant cliff near base of member ———————

Feet

11.0

5.5

- 40.5

14.0

12.0

10.0

6.0

10.0

————~ 6.0

10.0
476 THE SUPAI GROUP OF GRAND CANYON

Section 28—Continued 

PIGEON WASH-Continued

Section 28—Continued 

PIGEON WASH—Continued

Feet

9.0

Pakoon Limestone, cliff unit—Continued

Limestone, light-brownish-gray, aphanitic, irregularly bedded; largely concealed by talus; 

upper beds contain much irregular brown 

chert; locally forms thin, rounded ledges; 

mostly slope-forming ————————————

(Underlying units measured on south side of Pigeon Wash)

Limestone, pale-reddish-brown, very fine 

grained, sandy; cross-stratified on medium 

scale; contains small, rounded, dark-gray 

limestone pebbles scattered throughout upper part; weathers to brown or dark-gray 

cliff, with cross-stratification prominent —— 7.5

Siltstone-conglomeratic, reddish-brown; contains scattered pebbles of gray, aphanitic 

limestone (average diameter 0.25-0.5 in.; 

maximum 1 in.); forms weak ledge

Limestone, pale-reddish-brown, very sandy 

(48 percent very fine grained), crumbly, 

weakly bedded; largely concealed —————

Limestone, pale-reddish-brown, with grayishred laminae; contains very fine grained sand 

(46 percent); contains wedge-planar crossstratification on medium scale; weathers to 

brown and dark-gray cliff —————————

Total cliff unit, Pakoon Limestone —————————————— 214.5

Pakoon Limestone, slope unit:

Concealed slope, largely talus-covered; palereddish-brown, shaly, limy siltstone, locally

Sandstone, very pale orange with pale-reddishbrown specks, very fine grained (subangular), limy, friable; weathers to rounded

Concealed slope ————————————————

Limestone, pale-reddish-brown, very fine

grained, includes very fine (37 percent) sand; 

cross-stratified, medium-scale; weathers to 

resistant ledge with prominent brown and 

gray lamination ——————————————

Concealed slope —————————————

Conglomerate, red-brown to gray; contains 

gray limestone clasts; forms ledge ——————

Matrix: red-brown silt.

2.0

11.0

17.0

12.0

2.5 

25.0

17.0

12.0

2.0

Feet

Pakoon Limestone, cliff unit—Continued

Gravel: pebbles and granules of gray, 

aphanitic limestone; maximum diameter 1 

in., average 0.25-0.5 in.; subangular to 

rounded; oval to quadrate. _____

Total slope unit, Pakoon Limestone—————————————— 70.5 

Total Pakoon Limestone ———— 285.0 

Supai Group: 

Wescogame Formation, slope unit:

Concealed slope ————————————————— 5.5 

Limestone, pale-reddish-brown, sandy (30 

percent, very fine, subrounded), structureless; forms weak ledge ————————————— 6.5 

Concealed slope ————————————————— 5.5 

Dolostone, calcitic, moderate-orange-pink, 

sandy (17 percent, very fine grained); crossstratified on medium scale, wedge-planar 

type; weathers with brown and gray laminae 

prominently etched; forms resistant ledge — 13.0 

Concealed slope ————————————————— 6.0 

Limestone, dolomitic, pale-reddish-brown, 

aphanitic, silty (35 percent); contains scattered, very fine grained sand; structureless; 

series of rounded, receding ledges 2-3 ft 

thick-———————————————- 11.0

Total slope unit, Wescogame

Formation ——————————— 47.5 

Wescogame Formation, cliff unit:

Sandstone, moderate-reddish-orange, very 

fine grained (rounded), silty, calcareous, 

friable; contains cross-stratification on 

medium scale, low-angle; alternating with 

laminated gray and red, very sandy limestone; cross-stratified on medium scale (sets 

1-3 ft thick); weathers to platy slabs; forms 

slopes in most places, locally makes weak, 

receding ledges ————————————————— 33.0 

Limestone, grayish-orange-pink, aphanitic 

with scattered fine grains; cross-stratification, medium- to large-scale; laminae 

weather brown and gray; forms resistant 

ledge ————————-————-———- 8.5

Limestone, medium-light-gray; aphanitic with 

scattered fine grains; massive; weathers 

moderate-reddish-orange; forms resistant 

ledge —————————————————————— 4.0
MEASURED STRATIGRAPHIC SECTIONS 477

Section 28—Continued 

PIGEON WASH-Continued

Feet

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued 

Concealed slope, locally exposed pale-reddishbrown, shaly, sandy, siltstone ———————— 6.0 

Limestone, light-brownish-gray, fine-grained; 

horizontal bedding; thick-bedded (2-4 ft); 

forms rough, resistant cliff —————————— 7.5 

Sandstone, pale-reddish-brown, very fine 

grained, very limy (30 percent), crossstratified, wedge-planar type; weathers 

black to pink; forms resistant, rounded ledge 10.0 

Concealed slope, locally exposed moderateorange-pink, fine-grained sandstone ————— 5.0 

Limestone, grayish-pink; aphanitic, sandy; 

contains cross-stratification on large scale; 

forms small cliff ———————————————— 7.5 

Concealed slope ————————————————— 5.0 

Total cliff unit, Wescogame Formation ————————————— 86.5 

Total Wescogame Formation —— 134.0

Erosion surface: Broad depressions (10 ft deep)

filled with clayey limestone. 

Manakacha Formation, slope unit:

Concealed bench ————————————————— 2.0 

Sandstone, pale-gray, limy, cross-stratified; 

contains Fusulinella sp., Staffella sp.; forms 

weak ledge ——————————————————— 4.0 

Concealed slope ————————————————— 10.0 

Limestone, dark-gray, aphanitic; contains 

abundant crinoids and echinoids; forms

Iprlcrp ______________________________________ 7 fl ICTUgC A . v

Concealed slope ————————————————— 6.5 

Limestone, gray; contains jasper bands; forms

ledge ——————-—————-———-——- 2.0 

Limestone, well-laminated; medium-bedded

(1-2 ft); forms ledge —————————————— 2.0 

Limestone, gray, aphanitic; contains jasper

bands; forms ledge ——————————————— 3.0 

Mudstone, purple, crumbly, slope-forming —— 16.0 

Total slope unit, Manakacha

Formation ——————————— 47.5

Manakacha Formation, cliff unit:

Limestone, gray, contains irregular jasper 

bands; abundant casts of pelecypods; includes thin layer of ooids and kaolin grains 

at top; forms resistant ledge —————————— 3.0

Section 28—Continued 

PIGEON WASH-Continued

Feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Limestone, purple, sandy, thin-bedded, laminated; contains Fusulinella sp.; forms slope — 3.0

Limestone, light-gray, aphanitic; contains 

jasper bands in lower part, buff chert concretions above; contains crinoids and Bellerophontids, Fusulinella sp.; makes prominent marker bed of massive dark-gray ledges 8.5

Concealed slope, probably purple mudstone — 46.0 

Mudstone, deep-red-brown, brittle; forms

Concealed slope, locally exposed ———————— 14.5

Limestone, light-brownish-gray, aphanitic, 

medium-bedded (1-2 ft); contains accretal 

grains; forms rough, resistant ledge ————— 5.5

Limestone, grayish-pink, sugary, sandy (40 

percent), very fine grained (subrounded), 

flat-bedded; locally cross-stratified on 

medium scale; forms bench or weak ledge — 5.5

Limestone, light-brownish-gray, aphanitic; 

includes scattered very fine grained sand (30 

percent); contains prominent tabular-planar 

cross-stratification in sets 6-12 ft thick; 

weathers with brown and gray cross-laminae 

etched on surface; forms cliff ————————— 16.5

Sandstone, grayish-pink, very fine grained, 

very limy (40 percent), aphanitic, scattered 

fine-grained quartz; cross-stratification on 

large scale (beds 30-40 ft long); weathers 

dark-gray; forms massive bed at base of cliff - 14.0

Dolostone, calcitic, light-gray, earthy, 

medium-bedded (1-2 ft); weathers creamcolored; forms slope or receding, rounded 

ledges —————————————————- 17.0

Limestone, magnesian, pale-reddish-brown 

and grayish-pink, very fine grained, very 

silty; locally distinct conglomerate with 

angular fragments of jasper and chert; thinbedded (6-12 in.); laminae prominently 

etched on surface; forms brown, receding 

ledges———————_____________ 16.5
478 THE SUPAI GROUP OF GRAND CANYON

Feet

27.5

14.0

Section 28—Continued 

PIGEON WASH—Continued

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Limestone, light-brownish-gray, aphanitic to 

very fine grained, oolitic, silty clay (22 percent); contains irregular, white chert masses 

in lower part; contains thin jasper layers 

along stratification and large-scale crossstratification planes in upper part; forms 

series of thick ledges (3-10 ft); contains 

fossils below crossbedding (Neospirifer, 

Syringopora, Composita, Phricodothyris); 

contains large gastropods (bellerophontids) 

in red chert ———————————————

Limestone, pinkish-gray, aphanitic to very 

fine grained, silty; contains irregular thin 

beds, abundant nodules of gray to brown 

chert, and cores of red jasper; weathers 

lavender to cream; forms slope ———————

Limestone, medium-light-gray, aphanitic, 

silty (24 percent), thin- to medium-bedded 

(6-30 in.); contains thin jasper layers, fossiliferous (brachiopods); forms receding

Limestone, light-brownish-gray, aphanitic 

with scattered very fine grains, very silty (43 

percent); contains layers of large elliptical 

and spherical concretions of purplish quartzite that weather brown; forms thick ledge 

with flat vertical face ————————————

Limestone, medium-gray, aphanitic with scattered very fine grains, sandy; contains abundant jasper layers (locally 50 percent of 

rock); contains fossils (crinoid stems, 

Punctospirifer, Bellerophon); forms resistant

Total cliff unit, Manakacha Formation ————————————— 207.0 

Total Manakacha Formation —— 254.5

Watahomigi Formation:

Concealed slope, locally exposed, grayishpurple, crumbly mudstone and rubbly, 

crumbly, pale-reddish-brown dolostone near 

base, and a bright reddish-brown, brittle 

claystone at 33 ft above base; total forms 

slope —————————————————————— 65.0

Section 28—Continued 

PIGEON WASH-Continued

Supai Group—Continued 

Watahomigi Formation—Continued

Limestone, light-brownish-gray and palereddish-purple; aphanitic with scattered 

coarse grains; very silty, thin-bedded (2-12 

in.); contains fossils including algae(?), 

crinoids, and brachiopods (Neospirifer); 

forms receding ledges or slope ———————

Limestone, light-brownish-gray with palereddish-brown, aphanitic with scattered 

medium grains; contains abundant red accretal grains etched out on surface; weathers 

to resistant ledge —————————————

Siltstone, moderate-reddish-orange, limy; 

and medium-gray, aphanitic, concretionary 

limestone; total forms slope, largely conConcealed slope ——————————————

Feet

4.5

5.5

17.0

3.5

4.0 

4.5

Limestone, light-brownish-gray, aphanitic 

with scattered fine to coarse grains; mediumbedded (2-3 ft); contains much jasper in irregular layers, lenses, and spherical concretions; total forms series of three massive 

ledges, each 10-15 ft thick ——————————— 44.0

Limestone, medium-light-gray, aphanitic; 

contains irregular jasper layers with pink, 

platy, very fine grained sandstone partings 

above and below, forming prominent recesses 3.0

Limestone, medium-light-gray, aphanitic with 

scattered very coarse to very fine grains; 

thick-bedded (2-5 ft); abundant thin jasper 

layers (2-4 in.); contains many brachiopods 

(Spirifers); forms massive cliff ————————

Limestone, light-brownish-gray, mediumgrained with scattered coarse grains; contains thin layers and lenses of jasper; 

massive; forms three resistant ledges (5-8 ft); 

alternates with limestone; light-brownishgray and pale-red, aphanitic with scattered 

fine grains, hard, thin-bedded (6-12 in.) contains jasper layers (2-6 in.); includes weak 

units forming slopes and recesses; total contains fossils (Spirifer, echinoderms, small 

gastropods and crinoid joints) ————————

21.0

17.0
MEASURED STRATIGRAPHIC SECTIONS 479

Section 28—Continued 

PIGEON WASH-Continued

Section 28—Continued 

PIGEON WASH—Continued

Feet Feet

Supai Group—Continued 

Watahomigi Formation—Continued

Limestone, light-brownish-gray, aphanitic 

with scattered medium grains; mediumbedded (1-2 ft) with weak, shaly parting 

beds; weathers to purplish surface; contains 

fossils (fragments of stromatolites, crinoids, 

and brachiopods) that etch out on surface; 

forms receding ledges ————————————— 8.0

Limestone, magnesian, grayish-orange-pink, 

aphanitic with scattered fine to coarse 

grains; thick-bedded (3-5 ft); contains red 

silt parting-plane at base; weathers gray; 

contains brachiopods (Neospirifer) and 

crinoids; includes much bioclastic material; 

forms cliff ———————————————————— 12.5

Limestone, medium-light-gray to grayish-pink, 

aphanitic, thin- to medium-bedded (6-24 

in.); contains gastropods (like Naticopsis); 

forms bench or receding ledge ———————— 11.5

Limestone, light-brownish-gray; oolitic, lower 

part aphanitic with scattered fine to coarse 

grains; upper part largely fine-grained; 

thick-bedded (3-5 ft); weathers gray; contains abundant fossils: pelecypods (like 

Myalina), gastropods (Bellerophori), and 

brachiopods (Spirifer, Strophomina-type); 

includes a local shell concentration with 

nearly all shells concave downward; total 

forms lowest thick, resistant ledge —————— 20.0

Siltstone, brownish-gray, largely concealed; 

similar to 12-ft siltstone below; forms slope 16.5

Conglomerate, pink to gray; composed of 

clastic limestone, which is pebbly near base 

but conglomeratic above; contains scattered 

brachiopods (large spirifers, Orbiculoidial); 

forms resistant ledge —————————————— 7.5 

Matrix: limestone, reddish-brown, very

granular.

Gravel: includes pebbles and granules of 

light-gray, aphanitic limestone, deepreddish-brown mudstone, dark-gray limestone, and pale-reddish-brown siltstone; 

maximum size 2 in.; average size 0.25-0.5 

in.; mostly rounded, some subangular.

Siltstone, light-brownish-gray and palereddish-brown, limy, brittle, crumbly; largely concealed; forms slope ——————————— 12.0

Supai Group—Continued 

Watahomigi Formation—Continued

Limestone, medium-gray, aphanitic with scattered very fine grains; thin- to mediumbedded (2-3 in.); rubbly surface; forms ledge 2.0 

Mudstone, light-brownish-gray, silty; includes

some sand; brittle, crumbly; forms slope —— 5.5 

Limestone, medium-gray and pale-reddishbrown, aphanitic to very fine grained; 

sandy, thin-bedded (6 in.); forms ledge ——— 1.0 

Concealed slope ————————————————— 34.0 

Limestone, light-brownish-gray, aphanitic to 

very fine grained, silty; weathers olive-gray; 

forms rounded ledge with silty surface ——— 3.5 

Slope, partly concealed, contains reddishbrown, platy, silty sandstone ————————— 6.0 

Total Watahomigi Formation — 319.0 

Total Supai Group (without Esplanade Sandstone) and 

Pakoon Limestone —————— 992.5

Unconformity:

Surface of relief; two limestone ledges (total 

11 ft) of Redwall rise above base of measured 

section at 50 ft to west. 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, light-olive-gray, aphanitic; scattered fine grains; thin- to medium-bedded 

(6-24 in.); forms receding ledges.

Section 29 (part) 

GRAND GULCH MINE

[Measured northeast of mine]

Feet

Hermit Shale:

Mudstone and siltstone, pale-reddish-brown 

and moderate-reddish-orange; forms series 

of slopes and small ledges ——————————— 111.0 

Unconformity:

Assumed; not observed here. 

Supai Group:

Esplanade Sandstone, upper cliff-slope unit: 

Sandstone, very pale orange, very fine grained, 

planar cross-stratified; weathers to rounded, 

white ledge ——————————————————— 6.5
480 THE SUPAI GROUP OF GRAND CANYON

Section 29—Continued 

GRAND GULCH MINE-Continued

Feet

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope unit—

Continued

Siltstone, pale-reddish-brown; contains much 

sand; grains coated with iron oxide; brittle, 

structureless; forms slope ——————————— 7.0

Sandstone, moderate-reddish-orange, very fine 

grained (includes some fine-grained sand); 

grains coated with iron oxide, subrounded, 

very friable; contains wedge-planar crossstratification; forms weak ledge or slope —— 8.0

Sandstone, very pale orange, very fine grained; 

consists of two thick (4-ft) beds; forms 

prominent ledge ———————————————— 8.5

Siltstone, reddish-brown; like 11-ft siltstone 

below; contains worm borings; forms slope — 3.5

Sandstone, moderate-reddish-orange, very fine 

grained, friable, wedge-planar cross-stratification throughout on medium scale; forms 

rounded, weak cliff —————————————— 16.0

Sandstone, grayish-orange, very fine grained, 

silty (27 percent), friable, medium-bedded 

(0.5-1 ft thick); contains many shrinkage 

cracks, worm borings and Rivularites; forms 

ledge below small cliff ————————————— 2.5

Sandstone, reddish-brown, very fine grained, 

silty, friable, platy; weathers creamy-white; 

contains ledge (1-ft thick) of resistant, crossbedded siltstone; forms ledge ————————— 10.0

Siltstone, reddish-brown, shaly, friable; contains prominent planar-type cross-stratification; weathers creamy-white; forms ledge — 11.0

Siltstone, reddish-brown; includes very fine 

grained sand (46 percent), shaly; forms slope 11.0

Sandstone, moderate-orange-pink, very fine 

grained, silty, friable; weathers creamywhite; forms prominent ledge ———————— 5.0

Siltstone, moderate-reddish-orange, shaly; 

contains cross-stratification locally, structureless elsewhere ——————————————— 15.0

Sandstone, moderate-reddish-orange, very fine 

grained, silty, friable; forms receding ledges 

(mostly 2-4 ft thick); partly concealed ———— 55.0

Siltstone, pale-reddish-brown, mediumbedded (1-2 ft), structureless; forms weak

Siltstone, moderate-reddish-orange, sandy; 

forms thin (0.5 ft) ledges; contains imprint of 

conifer stem; largely concealed ———————— 5.5

Section 29—Continued 

GRAND GULCH MINE-Continued

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope unit—

Continued

Sandstone, moderate-reddish-orange and 

grayish-orange, very fine grained, friable; 

weathers to weak, rounded ledge ——————

Siltstone, moderate-reddish-orange, poorly 

sorted (angular grains), medium-bedded 

(1-1.5 ft thick), structureless; forms weak, 

rounded ledge and slope; partly concealed —

Sandstone, very pale orange and moderateorange-pink; very fine grained (scattered 

fine grains, 23 percent); contains planar 

cross-stratification with cosets 2-3 ft thick; 

massive; weathers gray and light-red-brown; 

forms resistant, gray cliff with rounded 

edges ———————————————————————

Siltstone, grayish-red; grains coated with iron 

oxide; brittle; forms slope; largely concealed

Sandstone, very pale orange, very fine grained, 

crumbly; forms rounded ledge (2 ft exposed) 

(Section projected north across extensive concealed area)

Limestone, gray to moderate-reddish-orange, 

very sandy, thin-bedded (2-12 in.); horizontal laminae weathered in relief: platy; forms 

weak ledge or cap of mesa ———————————

Sandstone, moderate-orange-pink, very fine 

grained, very crumbly; contains wedgeplanar cross-stratification; forms rounded

Concealed slope ————————————————— 

Sandstone, moderate-reddish-orange, very fine

grained, friable; locally contains planar

cross-stratification, elsewhere structureless;

forms resistant, rounded ledge ———————— 

Sandstone, moderate-orange-pink, very fine

grained, friable, medium-bedded (1-3 ft);

forms crumbly slope and receding, rounded

Siltstone, reddish-brown, shaly; forms slope — 

Sandstone, grayish-orange-pink, very fine 

grained, calcareous (34 percent), silty, thinbedded (2-12 in.); weathers with laminae 

and cross-laminae in relief; weathers 

reddish-brown; forms weak ledge, grading 

upward into slope ———————————————— 

Sandstone, moderate-orange-pink, very fine 

grained, calcareous (36 percent), thin- to 

medium-bedded (2-24 in.); forms slope and 

weak ledge; upper part largely concealed ——

Feet

5.5

8.0

19.5 

2.5 

2.0

3.0

17.0 

9.0

10.0

16.5 

5.0

11.0

9.0
MEASURED STRATIGRAPHIC SECTIONS 481

Section 29—Continued 

GRAND GULCH MINE-Continued

Section 30a (part)—Continued 

HIDDEN CANYON-Continued

Feet Feet

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope unit— 

Continued

Sandstone, grayish-pink, very fine grained, 

friable, medium-bedded (1-3 ft); forms 

rounded ledge ————————————————— 7.5 

Total upper cliff-slope unit, Esplanade Sandstone —————— 49.0 

Total Esplanade Sandstone ——— 294.0 

Pakoon Limestone:

Limestone, light-gray and pale-reddish-brown, 

medium-bedded (0.5-1 ft); weathers to gray 

and red-brown; forms flat blocks ———————— 5.0

Section 30a (part) 

HIDDEN CANYON

[Measured 3 miles south of Hidden Canyon; together with sections 30b 

and 30c, makes a complete section of Supai strata]

Feet

Supai Group:

Wescogame Formation, cliff unit (basal part): 

Siltstone, moderate-reddish-orange, shaly, 

slope-forming; not measured (see section at 

Hidden Canyon, 30b).

Limestone, grayish-red-brown, coarse-grained, 

sandy; contains cross-stratification on large 

scale, low-angle, planar-type, forms cliff —— 23.0 

Total cliff unit, Wescogame

Formation ——————————— 23.0 +

Manakacha Formation, slope unit:

Limestone, light-brownish-gray, coarsegrained, flat-bedded, medium- to thickbedded (2-20 ft); weathers to rough surface; 

forms series of receding ledges or weak cliff 38.0

Limestone, grayish-orange-pink, aphanitic, 

sandy; and sandstone, very fine grained, 

cross-stratified on medium scale with wedgeplanar sets; total forms cliff —————————— 5.5

Limestone, light-brownish-gray with palereddish-brown, aphanitic, flat-bedded; 

wavy laminae etched on surface; weathers to 

rough, pitted surface; forms receding ledges 6.0

Limestone, grayish-orange-pink, aphanitic, 

sandy, cross-stratified on medium scale, 

tabular-planar type; separated from overlying flat beds by irregular erosion surface; 

forms cliff ———————————————————— 14.0

Supai Group—Continued 

Manakacha Formation, slope unit—Continued 

Limestone, light-brownish-gray with palereddish-brown, aphanitic, medium-bedded 

(2-4 ft); weathers to rough, pitted surface; 

forms receding ledges ————————————— 15.0 

Total slope unit, Manakacha

Formation ——————————— 78.5

Manakacha Formation, cliff unit:

Limestone, grayish-orange-pink, mediumgrained, sandy; cross-stratified on medium 

scale, wedge-planar; reddish-brown laminae 

etched on lavender background; mediumbedded (1-4 ft); forms upper part of cliff —— 32.0 

Limestone, dolomitic, grayish-pink, aphanitic, 

flat-bedded, medium-bedded (1-2 ft); lower 

part sandy; contains abundant brachiopods 

(fig. E8); weathers to rounded surface near 

base, rough resistant surface above; forms 

cliff _____________________ 7.5

Limestone, grayish-pink and medium-lightgray; aphanitic to very fine grained, sandy 

(45 percent), and calcareous sandstone; 

cross-stratified on large scale; contains scattered thin, flat lenses (1 in. thick, 6-30 in. 

long) of chert parallel to crossbeds; forms 

weak cliff ———-——__________________ 46.0

Sandstone, grayish-orange-pink, sandy, very 

fine grained, flat-bedded, medium-bedded 

(1-2 ft); weathers to brown, pitted surface; 

forms receding ledges ————————————— 7.5

Sandstone, grayish-orange-pink, very fine 

grained, very limy (35 percent); crossstratified on large scale, planar-type, 

medium- to high-angle; weathers to brown 

surface; forms cliff ——————————————— 15.0

Limestone, light-gray, aphanitic; contains 

3-6 in. brown chert bed near top; fine ridges 

with dark-brown, wavy, reticulate pattern 

on surface; weathers with rough, pitted surface; forms cliff ————————————————— 5.0

Limestone, light-brownish-gray, aphanitic, 

sandy; contains a few lenses of jasper; locally upper part cross-stratified at low angle;

Limestone, dark-reddish-brown to grayishorange-pink, aphanitic, medium-bedded; 

contains many jasper beds, also concentric 

layers of jasper in spheres (6 in. diameters) 

forming layer near base; forms ledge ————— 3.0
482 THE SUPAI GROUP OF GRAND CANYON

Section 30a (part)—Continued 

HIDDEN CANYON-Continued

Section 30a (part)—Continued 

HIDDEN CANYON—Continued

Feet Feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued 

Limestone, dark-brownish-gray, aphanitic, 

sandy, medium-bedded (2-4 ft); laminae 

horizontal, etched on surface as brown lines 

on lavender background; locally includes 

jasper beds or lenses; contains fusulinids (fig. 

Ell) and brachiopods (fig. E3); forms cliff or 

receding ledges ————————————————— 11.0 

Limestone conglomerate, and dark-reddishbrown to grayish-orange-pink, aphanitic, 

thick-bedded (3-10 ft) limestone; contains 

abundant jasper beds, some horizontal, 

some crosscutting; contains many brachiopods, including jasperized spirifers; contains some pebbles of jasper at base; total 

forms massive cliff ——————————————— 16.5 

Total cliff unit, Manakacha Formation ————————————— 183.0 

Total Manakacha Formation —— 261.5

Watahomigi Formation, upper slope unit:

Mudstone, moderate-reddish-brown, silty, 

brittle, apparently structureless; much concealed; forms slope —————————————— 6.5

Limestone, olive-gray with dark-greenishgray, aphanitic, sandy; contains thin jasper 

lenses; weathers to olive-gray sandy surface 

with red-brown reticulate pattern of ridges; 

contains lenses of purple mudstone; forms 

ledge —————————————————————— 2.0

Limestone, grayish-orange-pink to light-purple,

silty, crumbly; forms slope —————————— 2.5

Conglomerate, medium-light-gray, mediumbedded (1-2 ft); very fossiliferous with 

brachiopods (fig. El), many archeocidaris 

spines, trilobites and bryozoans; contains 

jasper lenses; forms receding ledges ————— 8.5 

Matrix: aphanitic limestone. 

Gravels: gray limestone; mostly rounded; 

diameters range mostly from 0.25 to 1 in.

Concealed slope ————————————————— 10.0

Limestone, light-gray, very coarse grained, 

bioclastic, fossiliferous with brachiopods 

(fig. El) and pelecypods (fig. E3); forms two 

resistant ledges ————————————————— 4.0

Concealed slope ————————————————— 5.5

Supai Group—Continued 

Watahomigi Formation, upper slope unit— 

Continued

Limestone, magnesian, light-brownish-gray 

and greenish-gray, silty (39 percent), mottled, aphanitic, hard; weathers with darkreddish-brown wavy bands separating sets 

of low-angle cross-strata from sets of 

horizontal strata, each 1-8 in. thick; forms 

resistant ledge ————————————————— 3.0 

Siltstone, grayish-orange-pink, crumbly,

slope-forming ————————————————— 3.0 

Limestone, purple-gray and pale-buff, mottled, 

thin-bedded (6-12 in.); contains abundant 

brachiopods; weathers to olive-gray surface; 

forms rounded ledges ————————————— 9.5 

Concealed slope ————————————————— 32.0 

Total upper slope unit, Watahomigi Formation ——————— 86.5

Watahomigi Formation, middle cliff unit:

Limestone, light-olive-gray to grayish-pink, 

coarse-grained, thick-bedded (2-3 ft); contains prominent chert bed (marker bed) 2.5 ft 

thick; forms cap rock or small cliff —————— 13.0 

Limestone, light-gray, aphanitic, mediumbedded (1-3 ft); forms receding ledges with 

concealed slopes between —————————— 33.0 

Limestone, dolomitic, and limestone, lightbrownish-gray with pale-reddish-brown 

aphanitic with scattered coarse grains, 

medium-bedded (2-4 ft); contains jasper and 

chert nodules in irregular bands throughout; 

abundant jasper beds and lenses near top; 

weathers to rough, light-gray surface; forms 

resistant ledges ————————————————— 102.0 

Total middle cliff unit, Watahomigi Formation ——————— 148.0

Watahomigi Formation, lower slope unit:

Concealed slope, reddish surface, with thin 

ledges of reddish-brown siltstone, sandstone, and limestone, and patches of mudstone cropping out locally; limestone is light 

gray, aphanitic to fine-grained, weathers 

cream-colored; siltstone is very friable, 

laminated ———————————————————— 106.5 

Total lower slope unit, Watahomigi Formation ——————— 106.5 

Total Watahomigi Formation — 341.0 

Total Supai Group ———————— 625.0 +
MEASURED STRATIGRAPHIC SECTIONS 483

Section 30a (part)—Continued 

HIDDEN CANYON-Continued

Unconformity:

Surface of small relief, shallow channels and

ridges.

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, light-gray, aphanitic; locally replaced by coarsely crystalline pink dolomite; 

contains a few spherical gray flint concretions in layers; forms series of receding 

ledges above massive cliff —————————

Section 30b (part) 

HIDDEN CANYON

[Main part of Hidden Canyon section]

66.0

Feet

Hermit Shale: 

Contact:

Contact not described. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope unit:

Sandstone, grayish-orange-pink, very fine 

grained, slightly calcareous, weakly crossstratified on medium scale; forms rounded 

ledge at top of formation ——————————— 8.5

Siltstone, bright-reddish-brown, shaly; forms 

slope —————————————————————— 26.0

Sandstone, grayish-orange-pink, very fine 

grained, structureless at base, weakly crossstratified in upper part; forms weak cliff —— 25.0

Mudstone, bright-reddish-brown, flat-bedded;

forms slope, partly concealed ———————— 16.5

Sandstone, grayish-orange-pink, very fine 

grained, cross-stratified on large scale; forms 

small cliff ——————————————— 11.5

Siltstone, bright-reddish-brown; forms bench — 10.0

Sandstone, pink, flat-bedded to structureless; 

forms cliff continuous with underlying sandstone bed ———————————————————— 47.0

Sandstone, grayish-orange-pink, fine- to very 

fine grained, calcareous, cross-stratified on 

large scale; forms massive cliff with overlying sandstone ————————————————— 38.5

Siltstone, moderate-orange-pink shaly, 

slightly calcareous, flat-bedded, friable; contains Walchia sp.; includes one thin, weak 

ledge of pink siltstone in middle; total forms 

bench —————————————————————— 19.0

Section 30b (part)—Continued 

HIDDEN CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope unit—

Continued

Sandstone, pale-reddish-brown, very fine 

grained (subrounded), thick-bedded (5-15 

ft), structureless to weakly cross-stratified; 

forms massive cliff —————————————

Siltstone, bright-reddish-brown, flat-bedded, 

thick-bedded, friable; forms series of receding ledges ————————————

Sandstone, moderate-orange-pink, fine- to 

very fine grained (subrounded), slightly calcareous, cross-stratified on large scale; forms

CTV^ ail icui Oil fl i-ill 1 TT i _____ _———_—_ __________ _____——— _____________ _________ __ _

Siltstone, bright-reddish-brown, shaly to thinbedded; forms weak, thin ledges on long

Sandstone, pink, very fine grained (subrounded), well-sorted, calcareous, crossstratified on large scale (planes 30-40 ft 

long); forms cliff ————————————

Sandstone, moderate-reddish-orange, very fine 

grained (subangular to subrounded), calcareous, flat-bedded, massive; forms receding 

ledges on bench —————————————

Sandstone, moderate-orange-pink, poorly 

sorted and limy near base, very fine grained 

at top; includes scattered fine grains; crossstratified; includes two 1-ft thick beds of 

limestone, 5 ft and 15 ft above base; forms

Feet

60.5

— 22.0

20.0

93.5

28.5

36.0

——————— __ ———___ — ————— ____ ———— j^j ac t (\u

Concealed slope; includes a few thin ledges 

of moderate-orange-pink, calcareous, very 

fine grained sandstone and gray, muddy 

limestone ———————————————————— 71.5 

Total upper cliff-slope unit, Esplanade Sandstone —————— 569.0

Total Esplanade Sandstone ——— 569.0 

Pakoon Limestone, cliff unit:

Limestone, medium-light-gray, silty, mediumbedded (1-2 ft); contains scattered, nodular 

concretions that weather with black varnished surfaces; dolostone forms receding 

ledges; weathers to rough, buff surface ——— 16.5

Sandstone, pale-reddish-brown, very fine 

grained, very dolomitic (41 percent); 

weathers buff to brown; forms rounded

Siltstone, pale-reddish-brown, slightly

calcareous, crumbly; forms slope —

4.0 

2.0
484 THE SUPAI GROUP OF GRAND CANYON

Feet

31.0

14.0

2.5

Section 30b (part)—Continued 

HIDDEN CANYON-Continued

Pakoon Limestone, cliff-unit—Continued

Dolostone, pale-reddish-brown, fine-grained; 

contains abundant silicified fossils (crinoids, 

brachiopods, sea urchin spines); weathers to 

rough, buff surface; forms series of ledges ——

Siltstone, pale-reddish-brown, shaly; contains 

calcitic-dolostone (30 percent); forms slope, 

partly concealed ——————————————

Limestone, gray, fine-grained, medium-bedded 

(3 ft); contains chert lenses that weather 

black; contains fossils (brachiopods, sea urchin spines); forms prominent dark-gray 

ledge, conspicuous in light-gray sequence —-

Dolostone, calcitic, pale-reddish-brown, finegrained, medium-bedded (1-3 ft); contains 

abundant fossil fragments and unbroken 

brachiopods; weathers light-gray; forms

Concealed slope ——————————————

Dolostone, grayish-pink, very fine grained, 

thin-bedded (6-12 in.); weathers buff; forms 

weak ledge ———————————————————

Dolostone, calcitic, pale-reddish-brown, very 

fine grained with scattered fine to coarse 

grains; medium-bedded (2.5 ft); weathers to 

light-gray, sandy surface; forms ledge ————

Dolostone, calcitic, pale-reddish-brown with 

white blotches, very fine grained, massive; 

weathers to very rough, rounded surface;

Dolostone and calcitic-dolostone, grayish-pink 

to pale-reddish-brown, aphanitic, mediumto thick-bedded (1-4 ft); contains scattered, 

ellipsoidal concretions of chert, which 

weather black; brachiopods common near 

base; weathers light-gray; forms receding 

ledges or cliff —————————————————— 32.0

Limestone, medium-gray with pale-reddishbrown blotches, aphanitic with scattered 

fine grains, medium-to thick-bedded (1-3 ft); 

contains fossils (crinoids, sea urchin spines, 

brachiopods, colonial corals; abundant fragments); weathers to rough surface; forms 

cliff ————-———————————— 6.0

Section 30b (part)—Continued 

HIDDEN CANYON—Continued

Pakoon Limestone, cliff-unit—Continued

Limestone, dolomitic, pale-reddish-brown, 

aphanitic with scattered very fine to coarse 

grains; medium-bedded (1-3 ft); contains 

abundant fossils at 20 ft above base (bryozoans, horn corals, crinoids, sea urchin 

spines, and fusulinids); contains chert beds 

and lenses, many with abundant fusulinids; 

weathers light-gray; forms cliff ——————

Dolostone, calcitic, pale-reddish-brown, very 

fine grained; contains abundant small fossil 

fragments scattered throughout; weathers 

buff; forms ledge ————————————

Dolostone, calcitic, bluish-gray, earthy, 

aphanitic, medium-bedded (1-3 ft), locally 

laminated; weathers buff; forms ledges ———

Feet

13.0 

3.5

5.5

2.5

5.5

27.0

9.0

10.0

Dolostone, calcitic, pale-reddish-brown, 

aphanitic; contains abundant brachiopods; 

weathers buff; forms thin, receding ledges 

with straight faces ——————————————— 2.5

Limestone, dolomitic, medium-light-gray,

aphanitic, brittle; forms rounded ledge ——— 1.0

Concealed slope ————————————————— 5.0

Limestone, dolomitic, pale-reddish-brown, 

very fine grained, thin-bedded (2-6 in.); contains two beds of gray crinoidal limestone, 

one near middle, the other near top; contains 

a few bryozoans and brachiopods, abundant 

crinoids and horn corals; contains near top 

three layers of chert concretions that 

weather black; forms part of cliff; weathers 

buff —————————————————— 17.0

Limestone, light-brownish-gray, aphanitic 

with scattered fine grains; medium-bedded 

(1-3 ft); weathers to rough surface; forms 

part of main cliff ———————————————— 4.5

Dolostone, very pale orange, aphanitic, 

calcitic, thin- to medium-bedded (0.5-2 ft); 

casts of fossils common; forms part of cliff — 7.5

Dolostone, calcitic, grayish-orange-pink, fineto very fine grained; contains abundant casts 

of fossils; forms ledge ————————————— 2.0
MEASURED STRATIGRAPHIC SECTIONS 485

Section 30b (part)—Continued 

HIDDEN CANYON-Continued Feet

Section 30b (part)—Continued 

HIDDEN CANYON-Continued Feet

Pakoon Limestone, cliff-unit—Continued

Limestone, grayish-orange-pink, very fine 

grained with scattered fine and medium 

grains; crinoidal in part, elsewhere laminated or cross-laminated on medium scale; 

weathers gray to black with laminae prominently etched out on surface; crinoidal units 

1-5 in. thick; forms ledge ——————————— 10.0 

Total cliff unit, Pakoon Limestone —————————————— 233.5 

Pakoon Limestone, slope unit:

Sandstone, very pale orange and pale-reddishbrown, very fine grained (angular), calcareous, friable, structureless, medium-bedded 

(0.5-1 ft); includes thin beds of limestone 

near base; forms slope ————————————— 12.5 

Sandstone, grayish-orange-pink to brown, 

very fine grained, calcareous, massive, 

thick-bedded (2-4 ft); weathers white, locally with black varnish; forms resistant, conspicuous ledge ————————————————— 11.0 

Sandstone, grayish-pink, very fine grained 

(subangular to subrounded), calcareous, 

friable, thick-bedded (1-4 ft); locally forms 

rounded ledge, elsewhere concealed slope — 16.5 

Sandstone, pale-reddish-brown with moderate 

reddish-brown, horizontal laminae, very 

fine grained (subrounded), very limy (45 

percent); weathers to reddish-brown surface 

with conspicuous laminae; forms weak, 

rounded ledge ————————————————— 5.5 

Conglomerate, grayish-brown; forms ledge —— 2.0 

Pebbles: light-gray and dark-gray limestone; 

subrounded to rounded; mostly spheroidal, some elongate; average diameter 

0.25-0.5 in., maximum 1.5 in. 

Matrix: light-brownish-gray limestone. 

Limestone, pale-reddish-brown, fine- to very 

fine grained with scattered medium grains; 

shaly, very sandy, friable; forms slope ——— 5.0 

Limestone, pale-reddish-brown, medium- to 

coarse-grained, sandy, friable, flat-bedded; 

occurs as channel fill —————————————— 1.0 

Total slope unit, Pakoon Limestone —————————————— 53.5 

Total Pakoon Limestone ———— 287.0

Erosion surface. 

Supai Group:

Wescogame Formation, slope unit: 

Limestone, pale-reddish-brown, fine- to very 

fine grained; silty, cross-stratified on 

medium scale; cross-strata prominently 

etched on surface; forms part of cliff ————— 15.5 

Limestone, light-gray, locally moderatereddish-brown, medium- to very fine 

grained, crinoidal, thick-bedded (3-7 ft); 

light-brownish-gray and locally in upper 

part aphanitic with scattered coarse grains; 

reticulate siliceous pattern prominent on 

weathered surface; forms base of cliff ———— 21.0 

(Section continued on south side of Hidden

Canyon)

Concealed slope ————————————————— 4.5 

Total slope unit, Wescogame

Formation ——————————— 41.0

Wescogame Formation, cliff unit:

Sandstone, pale-reddish-brown, very fine 

grained (subangular to subrounded), limy, 

friable, structureless to weakly laminated; 

weathers reddish-brown; forms rounded 

ledges or slope ————————————————— 10.0

Concealed slope ————————————————— 2.0

Limestone, grayish-pink, very fine grained; 

scattered fine grains, silty, cross-stratified on 

medium scale; laminae prominently etched 

and reddish-brown on gray surface; forms 

weak cliff ———————————————————— 14.0

Dolostone, grayish-pink, medium-grained; 

weathers dark-gray to black; forms massive

Sandstone, grayish-orange-pink, very fine 

grained; scattered fine- to medium-grains; 

laminated; forms weak rounded ledges ——— 3.0 

Concealed slope ————————————————— 17.0 

Limestone, grayish-pink, fine- to very fine 

grained, medium-bedded (1-2 ft); locally 

grades into gray, aphanitic limestone containing abundant gastropods (Bellerophontidae); weathers to silty surface; forms weak 

ledge ————————————————————— 5.0
486 THE SUPAI GROUP OF GRAND CANYON

Section 30b (part)—Continued 

HIDDEN CANYON—Continued

Feet

Supai Group—Continued 

Wescogame Formation, cliff-unit—Continued

Limestone, light-brownish-gray, mediumgrained, silty, cross-stratified on medium 

scale; weathers with silty cross-strata etched 

on surface; forms ledge ———————————— 3.0

Limestone, magnesian, light-gray, aphanitic 

with scattered fine to very coarse grains; 

thick-bedded; weathers to rough, gray surface; forms ledge ———————————————— 6.5

Limestone, light-brownish-gray, aphanitic 

with scattered very coarse to very fine 

grains; weathers to rough, light-gray surface; forms weak ledge or recess ——————— 2.0

Concealed slope ————————————————— 3.5

Limestone, medium-gray, very fine grained 

with scattered coarse grains; contains concretions of dark-gray chert that weather 

blackish-brown; forms weak ledge or slope — 2.0

Limestone, very light gray, aphanitic with 

scattered fine to medium grains; weathers to 

rough surface; forms ledge —————————— 5.0

Dolostone, calcitic, pale-reddish-brown, fineto very fine grained, thin-bedded (0.5-1 ft); 

weathers pale-gray; forms receding ledges — 2.0

Limestone, magnesian, light-brownish-gray, 

fine- to very fine grained, sandy; crossstratified on medium scale, wedge-planar 

type; weathers to gray surface with reddishbrown strata prominently etched out; bedding units thick (2-4 ft); forms weak cliff —— 15.0

Limestone, very light gray, aphanitic, thickbedded (2-4 ft); weathers to rough surface; 

includes thin (2-ft) band of very fine grained, 

pale-reddish-brown dolostone, calcitic, that 

weathers to dark-gray band; forms massive 

cliff ————-—————————____— 15.0

Dolostone, calcitic, light-brownish-gray, aphanitic with scattered very fine grains; locally 

with reddish tinge, medium-bedded (1-2 ft); 

weathers to blocky surface; forms recess between massive cliffs —————————————— 6.0 

Total cliff unit, Wescogame Formation ————————————— 117.5 

Total Wescogame Formation —— 158.5 

Manakacha Formation, slope unit:

Limestone, yellowish-gray, aphanitic, mediumbedded (1-4 ft); includes thin (1 ft) parting of 

light-brownish-gray, aphanitic, sandy dolomite; weathers with reticulate siliceous pattern on surface; forms cliff —————————— 21.0

Section 30b (part)—Continued 

HIDDEN CANYON—Continued

Supai Group—Continued 

Manakacha Formation, slope unit—Continued 

Limestone, medium-gray, aphanitic, mediumbedded (0.5-2 ft); contains abundant, large 

horn corals; forms cliff ——————————

Feet

6.5

Total exposed slope unit, Manakacha Formation ——————— 27.5 +

Total measured Supai Group

and Pakoon Limestone ————1042.0 + 

Concealed beneath canyon bottom. See Section 30a.

Section 30c (part) 

HIDDEN CANYON

[Measured on east side of Jump Canyon, 0.5 mile from junction with 

Hidden Canyon]

Feet

Hermit Shale:

Basal slope unit:

Siltstone, moderate-reddish-orange; forms 

slope with rounded surface; locally shaly. 

Unconformity:

Erosion surface assumed; not observed here. 

Supai Group: 

Esplanade Sandstone, upper cliff-slope unit:

Sandstone, grayish-orange-pink, very fine 

grained, calcareous, resistant; crossstratified on medium scale; forms cap rock —

Siltstone, moderate-reddish-orange, calcareous, flat-bedded to shaly; weathers to massive, rounded ledge ———————————

Sandstone, grayish-orange-pink, very fine 

grained, calcareous, cross-stratified (smallscale, trough-type); forms rounded ledge; 

thickness doubles within 600 ft to north ———

Siltstone, moderate-reddish-orange, coarse, 

calcareous, shaly; forms slope ———————

Sandstone, grayish-orange-pink, very fine 

grained, calcareous, friable, structureless; 

forms rounded ledge ———————————

Siltstone, moderate-reddish-orange, coarsegrained, calcareous; massive near base, 

shaly above; forms slope ——————————

Sandstone, very pale orange, very fine grained, 

calcareous; weakly cross-stratified; mediumbedded (1-2 ft); weathers to knobby surface

Siltstone, moderate-reddish-orange, coarse; 

massive near base, shaly above; forms slope

7.5

5.5

6.5

10.0

4.0

4.5

4.0

8.5
MEASURED STRATIGRAPHIC SECTIONS 487

Section 30c (part)—Continued 

HIDDEN CANYON-Continued

Supai Group—Continued 

Esplanade Sandstone, upper cliff-slope unit— 

Continued

Sandstone, grayish-orange-pink, very fine 

grained, calcareous; cross-stratified on large 

scale; forms ledge ————————————

Siltstone, moderate-reddish-orange, coarse, 

calcareous; structureless to shaly; forms

Section 31—Continued 

ICEBERG CANYON-Continued

Feet Feet

Sandstone, grayish-orange-pink, very fine 

grained, slightly calcareous; forms ledge ——

Siltstone, moderate-reddish-orange, coarse, 

slope-forming —————————————

Siltstone, pale-reddish-brown, coarse-grained, 

calcareous, medium-bedded (1-2 ft); forms 

weak ledge ———————————————

Sandstone, pale-reddish-brown, very fine 

grained, slope-forming ——————————

Sandstone, grayish-orange-pink, very fine 

grained, slightly calcareous, structureless, 

ledge-forming —————————————

Sandstone, moderate-reddish-brown, very fine 

grained, silty, calcareous, structureless, 

slope-forming ———————————————

Sandstone, grayish-orange-pink, very fine 

grained, slightly calcareous, structureless, 

ledge-forming ——————————————

Sandstone, moderate-reddish-brown, very fine 

grained, silty, calcareous, slope-forming ——

Sandstone, grayish-orange-pink, very fine 

grained, resistant; forms ledge ——————

Sandstone, moderate-orange-pink, finegrained, calcareous, shaly, slope-forming ——_ 

Total upper cliff-slope unit, Esplanade Sandstone ————— 

Esplanade Sandstone, main cliff unit:

Sandstone, light-buff, massive, crossstratified.

Section 31 

ICEBERG CANYON

[Measured on east side; regional dip 45°]

Hermit Shale:

Siltstone, very pale reddish brown to very

light brown, shaly; forms long slope. 

Contact:

No erosion channels apparent in this area, 

but thickness of underlying sandstone ranges 

from 4 to 12 ft in distance of 0.25 mile.

5.0

8.5 

2.0 

2.0

11.0

11.0

4.0 

2.0

6.0 

5.5 

2.0 

3.5

113.0 +

Feet

Supai Group: 

Esplanade Sandstone, upper cliff-slope unit:

Sandstone, grayish-orange-pink, very fine 

grained, friable; forms massive, rounded 

ledge ———————————————— 4.0-12.0

Siltstone, moderate-reddish-brown, shaly; 

alternating with moderate-reddish-orange to 

light-brownish-orange with brown speckles, 

very fine grained, friable, thin-bedded sandstone; contains some very thin bedded, 

yellowish-gray limestone (insoluble 11 percent); total forms long slope with weak 

ledges —————————————————————— 218.0

Sandstone, grayish-orange-pink with reddishbrown speckles, very fine grained, very 

friable; contains medium-scale crossstratification; weathers bright-reddishbrown; forms massive, crumbly ledge ———— 7.0

Siltstone, moderate-reddish-orange, very fine 

grained (subrounded), calcareous; locally 

crops out on largely concealed slope ————— 65.0

Dolostone, calcitic, grayish-pink, silty (48 percent), and olive-gray, thin-bedded (2-6 in.) 

limestone; includes interbedded reddishbrown siltstones; forms receding ledge, more 

resistant upward ———————————————— 24.0

Concealed slope ————————————————— 53.0

Dolostone, calcitic, grayish-orange-pink, silty 

(12 percent), thin-bedded (6-12 in.); weathers to rough, pitted surface; forms ledge —— 3.0

Limestone, moderate-reddish-orange, friable, 

silty, argillaceous, insoluble (21 percent); 

weathers to rough black surface; forms slope 11.0

Dolostone, grayish-orange-pink, silty (15 percent); weathers to smooth gray surface; 

forms ledge ——————————————————— 1.0

Sandstone, moderate-reddish-orange, very 

fine grained, silty, friable, very calcareous; 

weathers to rough surface; forms weak 

ledges or slope ————————————————— 18.0

Sandstone, moderate-orange-pink, very fine 

grained, very calcareous; weathers to pitted, 

rough surface, porous; forms weak ledge —— 11.5 

Total upper cliff-slope unit, Esplanade Sandstone —————— 423.5

Contact:

No unconformity apparent in this area; lithologic change marks boundary.
488 THE SUPAI GROUP OF GRAND CANYON

Section 31—Continued 

ICEBERG CANYON-Continued

Feet

Pakoon Limestone, cliff unit:

Dolostone, very pale orange, very fine 

grained, silty (30 percent), thin-bedded (2-6 

in.), laminated; forms weak bench ————— 5.5

Dolostone, light-olive-gray, fine-grained, silty, 

thin-bedded (1-2 in.); contains local chert 

lenses, 1-2 in. thick; forms series of ledges — 8.5

Dolostone, very pale yellowish-gray, very fine 

grained, silty (15 percent), thin-bedded (6-12 

in.); weathers tan with cross-laminae etched 

on surface; forms ledge ———————————— 5.5

Dolostone, very pale orange, aphanitic, 

weakly bedded; beds 1-3 ft thick; locally 

contains scattered intraformational fragments of silty limestone, including laminated 

types, 6-8 in. across; weathers gray-brown, 

very rough and pitted; red-brown oxidation 

most intense toward top; forms cliff ————— 39.0

Limestone, dolomitic, olive-gray with lightbrownish-gray, silty (30 percent), finegrained; contains abundant small fossils 

(crincids, corals, brachiopods); contains intraformational conglomerate near top with 

fragments of shaly limestone as long as 6 in.; 

weathers yellowish-brown to dark-gray; 

forms ledge ——————————————————— 2.5

Mudstone, yellowish-gray with moderatereddish-orange; weathers reddish-brown; 

forma slope ——————————————————— 6.5

Limestone, dolomitic, olive-gray, very fine 

grained, even, flat beds, 0.5-2 ft thick; 

weathers light-gray; contains abundant 

crinoids near top; forms ledge ———————— 4.0

Dolostone, calcitic, pale-orange-pink, silty, irregularly bedded; forms slope ———————— 3.0

Limestone, grayish-orange-pink, fine-grained 

to aphanitic, beds thin (0.5-1 ft); weathers to 

rough, gray surface; forms ledge ——————— 4.0

Limestone, dolomitic, grayish-pink, fine- to 

medium-grained, silty; beds thin (2-6 in.); 

contains abundant but scattered fossils; 

weathers to silty, brownish surface; forms 

slope ——————————————————————— 4.0

Limestone, dolomitic, olive-gray, fine-grained, 

silty (35 percent), thick-bedded (2-4 ft); 

weathers to rusty-brown, rough surface; 

laminae highly contorted locally; forms 

ledge ——————————————————————— 15.0

Section 31—Continued 

ICEBERG CANYON—Continued

Pakoon Limestone, cliff unit—Continued

Limestone, dolomitic, and limestone, olivegray to pale-reddish-brown, fine-grained; 

aphanitic and pure gray near top; contains 

fossils (urchin spines, crinoids, and 

brachiopods) near top; weathers to rough, 

sandy surface; forms ledge ———————

Limestone, dolomitic, light-olive-gray, 

medium-grained, silty; contains planar 

cross-strata etched prominently on surface; 

weathers brown; convolute structure locally 

developed; forms ledge ——————————

Limestone, dolomitic, brownish-gray, speckled 

with pale-reddish-brown, medium-grained, 

thick-bedded (2-4 ft); weathers to rough, 

brown surface; forms ledge —————————

Dolostone, light-olive-gray, speckled with 

pale-reddish-brown, very fine grained, 

mostly thick-bedded (2-4 ft), but thinbedded (6-12 in.) near top; contains abundant corals and many silicified mounds; contains fragments of reddish-brown siltstone 1 

in. in diameter near top of limestone; lower 

part forms cliff; upper part forms receding

Limestone, dolomitic, pinkish-gray, very fine 

grained, thick-bedded (2-4 ft); contains 

abundant nodules of chert, which weather 

black; contains crinoids and urchin spines 

scattered throughout; forms weak ledge ——

Limestone, dolomitic, dark-grayish-pink, 

aphanitic, thick-bedded (2-6 ft); weathers 

rough, gray; contains scattered chert concretions; contains abundant fossils (lithostrotion and other colonial corals, urchin spines, 

crinoids, bryozoa, Deltodus, abundant 

fusulinids; including Schubertellids, Triticites); forms cliff ——————————————

Dolostone, calcitic, grayish-pink, very fine 

grained, thin-bedded (0.5-1 ft); contains 

chert nodules, which weather black; very 

fossiliferous in upper part (fusulinids, horn 

corals, crinoids, bryozoans, and urchin 

spines); weathers buff to cream; forms weak

I f*(} ffP —~———————«—.—.———————..——.—»—______«-.__ _________„

Limestone, pale-gray, fine-grained, beds 1-2 ft 

thick; weathers rough; forms ledge —————

Feet

6.0

3.0

11.0

19.0

29.5

11.5

13.0
MEASURED STRATIGRAPHIC SECTIONS 489

Section 31—Continued 

ICEBERG CANYON-Continued

Pakoon Limestone, cliff unit—Continued

Limestone, dolomitic, dark-grayish-pink, very 

fine grained with scattered large grains up to 

3 mm; beds 1-2 ft thick; contains silicified 

fossil fragments and concretions with abundant crinoids; weathers to smooth face; 

stained brown; forms recess ———————

Limestone, olive-gray, fine-grained; beds 1-2 ft 

thick; contains fossils (colonial corals, horn 

corals, brachiopods, many foraminifers, 

gastropods and urchin spines); weathers to 

rough surface; forms ledge ————————

Limestone, light-olive-gray with pale-reddishbrown, fine-grained, silty, cross-stratified on 

large scale (sets 2-15 ft thick); weathers with 

thin, reddish-brown bands on light-gray surface; some following cross-strata, others 

crosscutting; forms cliff ————•

Sandstone, light-olive-gray speckled with palereddish-brown, very hard, quartzitic, calcareous, thick-bedded (2-3 ft); laminae nearly 

horizontal, locally wavy; weathers to 

smooth face with black varnish; forms prominent dark layer at base of cliff —————— 

Total cliff unit, Pakoon Limestone ——————•

Feet

4.5

4.0

—- 16.5

7.0

_____—.__ 258.0

Pakoon Limestone, slope unit:

Sandstone, grayish-red, very fine grained, 

calcareous; weathers to thick (1-3 ft) 

rounded beds; contains many limestone 

pelloids; forms weak ledge —————————— 17.5 

Mudstone, reddish-brown, shaly; locally contains cusp-type ripple marks and worm 

tubes; contains a few weak ledges of calcareous, lavender siltstone; forms slope ————— 16.5 

Conglomerate, brownish-gray; fills broad 

channel in underlying limy sandstone ———— 3.0 

Gravel: includes (a) blocks of limestone, 

maximum 10 in. long; many 5 in. long; 

gray with silty surface; also gray with 

reddish-brown silty laminae etched on 

surface; some imbricated, mostly flat; and 

(b) small pebbles of reddish-brown siltstone, dark-gray limestone, and light-gray 

limestone; some angular, mostly rounded; 

mostly 0.25-1 in. in diameter; rude 

layering.

Section 31—Continued 

ICEBERG CANYON—Continued

Pakoon Limestone, slope unit—Continued 

Conglomerate—Continued

Matrix: light-gray, fine-grained limestone.

Total slope unit, Pakoon Limestone ——————————————_ 

Total Pakoon Limestone ———— 

Supai Group: 

Wescogame Formation, slope unit:

Limestone, dark-grayish-pink, silt and sand (35 

percent), resistant; contains low-angle, 

planar cross-strata in sets 0.5-2 ft thick; contains plant stems and branches of Walchia; 

locally less limy with shale partings or lenses 

as much as 3 ft thick; weathers with black or 

brown laminae etched out on gray surface; 

forms ledge ———————————————

Siltstone, pale-reddish-brown, shaly; forms 

slopes 2-3 ft thick; alternating with 

moderate-reddish-gray, very fine grained, 

ripple-laminated, calcareous (30 percent) 

sandstone; forms weak ledges 2-6 ft thick; 

locally structureless; develops spheroidal 

weathering; ratio of siltstone to sandstone,

±»Zt —————————————————————————————*•————————————

Total slope unit, Wescogame 

Format ion —————————— 

Wescogame Formation, cliff unit:

Dolostone, calcitic, light-olive-gray to palereddish-brown, aphanitic; forms resistant

Sandstone, grayish-orange-pink, very fine 

grained, crumbly, calcareous; forms slope —

Limestone, grayish-orange-pink, fine-grained; 

insoluble residue (35 percent) contains (2-6 

ft) thick wedge-planar cross-stratification; 

weathers with brown silt layers etched on 

gray surface; forms cliff ———————————

Limestone, light-gray, very fine grained; 

weathers to rough surface with black siliceous outlines; forms base of cliff ——————

Concealed slope ————————————————

Dolostone, calcitic, moderate-reddish-orange, 

very fine grained, silty, thick-bedded (2-4 

ft); contains chert concretions locally; 

weathers to rough, gray surface; forms resistant ledge ————————————————

Limestone, grayish-orange-pink, very silty; 

weathers to brownish silty surface; forms

feet

37.0

295.0

28.0

40.5

68.5

1.0 

3.0

47.0

5.5 

6.0

5.0

7.5
490 THE SUPAI GROUP OF GRAND CANYON

Section 31—Continued 

ICEBERG CANYON-Continued

Supai Group—Continued 

Wescogame Formation, cliff unit—Continued 

Limestone, pale-grayish-pink, medium-grained; 

beds 1-2 ft thick; contains horizontal bands 

of silt, 1-2 in. apart; forms ledge ————— 

Limestone, dark-olive-gray, very fine grained; 

beds 1-2 ft thick; weathers to rough surface; 

forms ledge ——————————————

Dolostone, calcitic, moderate-reddish-orange, 

fine-grained, silty (35 percent), mediumbedded (6-24 in.); weathers to rough, silty, 

buff-colored surface; forms series of ledges —_ 

Total cliff unit, Wescogame ForITiciLlOn ——————————————————

Feet

8.5

6.0

22.0

Section 31—Continued 

ICEBERG CANYON-Continued

Supai Group—Continued 

Manakacha Formation, slope unit—Continued 

Limestone, grayish-pink, fine-grained, very 

silty, friable; grades upward into pink siltstoncj ronns siopc ———————————————

Total slope

Feet

Total Wescogame Formation —— 180.0

Manakacha Formation, slope unit:

Limestone, grayish-orange-pink, fine-grained,

silty; forms ledge ———————————————— 5.0

Limestone, light-brownish-gray, very fine 

grained; weathers to rough surface; forms 

ledge —————————————————————— 6.0

Limestone, grayish-orange-pink, fine-grained,

silty; forms ledge ———————————————— 5.0

Concealed slope ————————————————— 2.0

Limestone, light-olive-gray, aphanitic to 

medium-grained; weathers to rough surface; 

forms ledge ——————————————————— 2.0

Sandstone, dark-grayish-pink, very fine 

grained, limy (41 percent); forms ledge ——— 7.0

Limestone, grayish-orange-pink, silty; weathers to brownish, silty surface; forms weak 

ledge —————————————————————— 11.0

Limestone, grayish-orange-pink, silty, crossstratified; weathers gray; forms ledge ———— 3.0

Siltstone, pink, calcareous, crumbly; forms

Limestone, very light brownish-gray, finegrained, silty (18 percent), cross-stratified; 

weathers to gray surface with brown streaks; 

forms ledge ——————————————————— 12.0

Sandstone, dark-grayish-pink, very fine 

grained, limy (40 percent); contains wedgeplanar cross-stratification; weathers to 

brown silty surface; forms ledge ——————— 17.5

Sandstone, very pale grayish-orange, fine- to 

very fine grained; many medium grains (well 

rounded); very limy, cross-stratified; contains irregular jasper beds; forms ledge ——— 2.5

35.0

unit, Manakacha 

Formation ——————————— 114.5

Manakacha Formation, cliff unit:

Limestone, dolomitic, very light-brownishgray, medium-grained, very sandy (44 percent), platy; contains horizontal lamination 

and local cross-lamination; laminae etched 

on surface; weathers to brownish, silty surface; forms cliff ————————————————— 25.5

Sandstone, grayish-orange-pink, very fine 

grained, crumbly, calcareous (30 percent); 

contains massive sets of cross-strata (2-3 ft 

thick); tabular-planar type cross-stratification with very even planes; many flatbedded strata in upper half; forms cliff ——— 43.0

Limestone, dolomitic, medium-light-gray, 

medium-grained; contains abundant concretions and irregular masses of chert, which 

weather black; limestone weathers very 

rough; forms cliff ——————————————— 5.5

Siltstone, pink, crumbly; forms slope ————— 4.5

Limestone, pale-red-purple, fine-grained, silty 

(45 percent), very hard; weathers to brown, 

silty bands; forms ledge ———————————— 2.0

Limestone, dark-gray, aphanitic; contains

much chert; forms ledge ———————————— 2.0

Siltstone, pink, crumbly, calcareous; contains single thick chert layer near middle; 

forms slope ——————————————————— 10.0

Limestone, pale-red, very fine grained, sandy 

(47 percent); contains thin, flat laminae 

etched on surface; weathers brown; forms 

ledge —————————————————————— 6.5

Limestone, light-olive-gray, very fine grained 

(insoluble 27 percent); contains tabularplanar cross-stratification; weathers to silty

SUIT clCC —————————————————————————— J.. O

Sandstone, grayish-pink, very fine grained, 

very silty, crumbly, calcareous; contains 

jasper layer (1 ft thick) near base; forms 

ledge —————————————————————— 4.5

Limestone, dolomitic, very pale grayish-orange, 

very fine grained, silty (51 percent); forms 

resistant, rounded ledge ——————————— 2.0
MEASURED STRATIGRAPHIC SECTIONS 491

Section 31—Continued 

ICEBERG CANYON-Continued

Feet

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Limestone, dolomitic, grayish-orange-pink, 

very fine grained, silty (45 percent); contains 

brachiopod sections; weathers tan with gray 

streaks; forms rounded ledge ————————— 5.5

Limestone, grayish-red-brown, fine-grained, 

very sandy (30 percent); contains crossstratification (wedge- and trough-types) on 

medium scale; weathers purple-brown with 

laminae etched on surface; forms resistant 

ledge —————————————————————— 11.0

Limestone, medium-light-gray, fine-grained, 

thin-bedded (0.5-2 in.), platy; surfaces show 

many fossil traces, especially bryozoan; contains jasper lenses and concretions; weathers 

pale-gray; forms weak ledge ————————— 8.5

Limestone, light-gray, fine-grained, evengrained; contains thin, brown, silty layers, 

1-2 in. apart, which weather to conspicuous 

brown bands; forms resistant ledge ————— 6.0

Limestone, medium-light-gray, fine-grained; 

contains thick, irregular jasper lenses; forms 

resistant ledge ————————————————— 4.5

Limestone, pale-pinkish-gray, mediumgrained, even-grained; weathers to sandy 

surface; forms part of cliff —————————— 3.5

Limestone, olive-gray, aphanitic, thick-bedded

(3-6 ft); contains abundant thin (1-2 in.)

layers of jasper and white chert, roughly

parallel to bedding; forms resistant ledge —— 17.0

Total cliff unit, Manakacha

Formation ——————————— 163.0 

Total Manakacha Formation —— 277.5

Watahomigi Formation:

Concealed slope ————————————————— 8.0

Limestone, grayish-pink with light-olive-gray, 

very fine grained, silty (30 percent), thinbedded (2-12 in.); forms weak ledge ————— 3.0

Concealed slope; probably reddish-brown

beds _______________________ 10 0

Limestone, grayish-red, very fine grained, 

thin-bedded (2-12 in.); weathers light-gray; 

forms ledge ——————————————————— 2.0

Chert, white, brittle; forms slope ———————— 5.0

Concealed slope, probably reddish-brown

beds __~___•__________•______ 6 0

Mudstone, grayish-red-purple, very fine 

grained, dolomitic, very hard; weathers with 

black varnish; forms ledge —————————— 1.0

Section 31—Continued 

ICEBERG CANYON—Continued

Supai Group—Continued 

Watahomigi Formation—Continued

Concealed slope, probably reddish-brown

Limestone, light-brownish-gray, very fine 

grained; includes scattered grains up to 

1 mm; contains brachiopod casts; weathers 

light-gray; forms ledge —————————————

Concealed slope, probably reddish-brown

Limestone, grayish-red, fine-grained, thinbedded (2-4 in.); forms weak ledge ————

Limestone, medium-light-gray, very fine 

grained, thin-bedded (6-12 in.); alternating 

with grayish-pink, very fine grained, thinbedded calcitic-dolostone; weathers buff; 

rorms dirt —~—•-—---—————————————--——

Limestone, medium-light-gray, very fine 

grained; includes scattered grains up to

Feet

5.5

1.0

- 4.5

2.0

64.0

1 mm; thick-bedded (3-6 ft); contains scattered chert lenses; forms cliff ————————— 60.5

Limestone, dark-gray, very fine grained; contains layers of concretionary chert; contains 

brachiopods (Spirifer, productids); forms 

ledge -—-——————-—________ 3.0

Dolostone, grayish-white, fine-grained, thickbedded; weathers to buff, pitted surface; 

forms ledge ——————————————————— 16.5

Dolostone, pale-pinkish-gray, medium-grained; 

weathers to tan surface; contains silty 

laminae and thin silicified layers; forms 

ledge ——————————-—————— 2.0

Dolostone, pale-pinkish-white, mediumgrained, thick-bedded (2-15 ft); weathers 

dark-gray with rough, pitted surface; contains three lensing layers of brownweathering chert, each 1-2 ft thick, at 

distances of 27 ft, 49 ft, and 62 ft from bottom; contains trilobites at 19 and 41 ft up; 

forms cliff ———————————————————— 77.0

Concealed slope; probably reddish-brown,

shaly siltstone ————————————————— 27.5

Limestone, pale-reddish-brown, very sandy 

(47 percent), thin- to medium-bedded (2-24 

in.); irregularly bedded; forms ledge ————— 2.0

Dolostone, calcitic, grayish-orange-pink, finegrained, sandy (30 percent), shaly, friable; 

rOriiiS

Total Watahomigi Formation — 304.0 

Total Supai Group and Pakoon

Limestone ——————————— 1480.0
492 THE SUPAI GROUP OF GRAND CANYON

Section 31—Continued 

ICEBERG CANYON-Continued

Unconformity 

Redwall Limestone: 

Horseshoe Mesa Member:

Limestone, pale-gray, aphanitic, thin-bedded 

(0.5-1 ft); locally dolomitized with medium 

crystalline texture, white; contains corals, 

foraminifers (204)

Section 32 (part) 

SELIGMAN

[On Aubrey Cliffs, 4 miles west of Seligman]

Hermit Shale: 

Unconformity:

Assumed. 

Supai Group: 

Esplanade Sandstone, main cliff unit:

Sandstone, pale-reddish-brown, calcareous, 

thick-bedded, cross-laminated, cliffforming; alternates with pale-reddishbrown, friable, structureless sandstone; 

slope-forming; unit forms series of cliffs and 

slopes —————————————————

Sandstone, pale-reddish-brown, very fine 

grained, calcareous; includes sandy, crystalline limestone; beds near base very thick, 

near top, thinner; middle portion structureless, weakly cemented; weathers to palereddish-brown; forms massive cliff with 

bench at weak, middle portion ———————

Siltstone, dark-reddish-gray, calcareous, 

weakly cemented; forms slope with rounded

Limestone, reddish-gray, fine-grained, crosslaminated; weathers pak'-brown, sandy surface with laminae etcned out; forms cliff 

with straight face and sharp edges —————

Concealed, probably pale-reddish-brown, 

thin-bedded siltstone ———————————

Sandstone, pale-reddish-brown, uniformly 

very fine grained, calcareous, crosslaminated (prominently at base); beds 2-4 ft 

thick; weathers pale-reddish-brown; forms 

massive cliff, rounded at top —————————

Section 32 (part)—Continued 

SELIGMAN—Continued

Feet Feet

12.0

53.5

77.0 

4.5

9.5 

11.0

Supai Group—Continued 

Esplanade Sandstone, main cliff unit— 

Continued

Limestone, reddish-gray, fine-grained, crosslaminated, cliff-forming; like limestone 

above but less sandy —————————————— 3.0 

Total main cliff unit, Esplanade

Sandstone ——————————— 170.5 

Esplanade Sandstone, basal slope unit:

Concealed, probably pale-reddish-brown,

thin-bedded siltstone ————————————— 17.0 

Siltstone, reddish-gray, calcareous, structureless; weathers same color; forms rounded

Siltstone, pale-reddish-brown, argillaceous, 

thin-bedded (less than 0.5 in.); weathers 

same color; forms slope ———————————— 23.0

Siltstone, reddish-gray to light-brown, calcareous, cliff-forming; weathers to paleSiltstone, pale-reddish-brown, thick-bedded, 

structureless; forms weak cliff with rounded 

surfaces ————————————————————— 33.0 

Conglomerate, forms rounded massive ledge — 11.0 

Matrix: reddish-gray silt. 

Gravel: commonly 2-4 in. in diameter, as 

much as 8 in.; mostly well-rounded, palebrown, reddish-gray, and light-brownishgray limestones and siltstones. ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 90.0 

Total Esplanade Sandstone ——— 260.5 

Wescogame Formation, slope unit:

Limestone, dark-reddish-gray, crystalline; 

weathers to pale-brown, sandy surface; 

forms cliff ———————————————————— 6.0 

Concealed, probably continuation of overlying limestone.

Section 34 

SEPARATION CANYON

[Measured on south side of Colorado River at Separation Canyon, east 

of Spencer Canyon]

Tertiary rocks:

Basaltic flows and stream gravels of Tertiary 

12.0 age forming cap of mesa.
MEASURED STRATIGRAPHIC SECTIONS 493

Section 34—Continued 

SEPARATION CANYON—Continued

Contact:

Irregular surface of Tertiary erosion. 

(Base of slope unit of Manakacha to top of 

Supai Group, measured on east side of lavacapped hill). 

Supai Group:

Esplanade Sandstone, main cliff unit:

Sandstone, grayish-pink, very fine grained, 

very limy (45 percent), thick-bedded; weakly cross-stratified on medium to large scale; 

locally friable; forms massive cliff at top of

Total main cliff unit, Esplanade 

Sandstone ———————————

Feet

11.0 —_———._. 49.5

11.0 +

Esplanade Sandstone, basal slope unit:

Sandstone, pale-reddish-brown, structureless, 

very fine grained, calcareous, silty; grains 

with iron oxide coatings; forms recess below 

massive cliff; lower part of slope concealed — 11.0 

Siltstone, deep-reddish-brown, thin-bedded 

(0.5-1 in.); contains horizontal laminae and 

cross-laminae; resistant; forms receding 

ledges —————————————————————— 10.0 

Conglomerate, grayish-red; forms massive 

ledge -———————-———-——————- 2.0-10.0

Matrix: granule-sized limestone clasts and

quartz sand. 

Cement: calcareous.

Gravel: pale-reddish-brown siltstone, lightgray, medium-gray and grayish-pink limestone; mostly well-rounded, some 

subrounded; average diameters 0.5-1 in. 

(maximum 3 in.). ____ 

Total basal slope unit, Esplanade

Sandstone ——————————— 31.0 

Total Esplanade Sandstone——— 42.0 +

Wescogame Formation, slope unit:

Siltstone, reddish-brown, shaly; consists of 

thin, flat beds; includes one resistant, sandy, 

limestone bed; forms bench —————————— 15.0

Total slope unit, Wescogame

Section 34—Continued 

SEPARATION CANYON-Continued

Supai Group—Continued

Wescogame Formation, cliff unit:

Sandstone, grayish-orange-pink, very fine 

grained, limy (37 percent), thick-bedded 

(2-4 ft); cross-stratified on medium to large 

scale (tabular-planar, wedge-planar, locally 

trough type); forms series of receding ledges 

and small cliffs; includes limestone ledge 

near middle; weathers to rounded edges and 

surface of dark-gray or black varnish; 

friable; contains 16 ft of very massive ledges 

at 30 ft above base ————— 

Sandstone, pale-reddish-brown, very fine 

grained, very limy (49 percent); crossstratified (medium-scale); forms resistant 

ledge; weathers to black surface with 

laminae strongly etched in relief ——————— 

Concealed slope ————————————————— 

Conglomerate, varicolored; dominantly gray, 

with reddish-brown and purple ——————— 

Matrix: gray, granular limestone; dominated 

by medium-size clasts; includes many 

granule-size clasts.

Gravel: gray, aphanitic limestone; purple, 

silty limestone; reddish-brown siltstone 

(dominant); angular, red jasper (rare); 

angular, white chert; medium-grained, 

brown sandstone; average 0.5-1 in. in 

diameter (maximum 3 in.); mostly subangular to rounded.

Total cliff unit, Wescogame

Formation ———————————

Feet

2.0

5.5

2.0

59.0

Formation ——— 15.0

Total Wescogame Formation —— 74.0

Manakacha Formation, slope unit:

Sandstone, pale-reddish-brown, very fine 

grained, very limy (47 percent), crossstratified (medium-scale); forms ledges 

(0.5-2 ft); alternating with pale-reddishbrown, very fine grained, shaly, flat-bedded 

sandstone; forms slopes, much concealed —— 15.5

Sandstone, pale-reddish-brown, very fine 

grained, very limy (49 percent), shaly; some 

horizontally laminated, some crosslaminated; includes 5 ft, weak, rounded 

ledge of siltstone; total much concealed; 

forms long slope ———————————————— 25.0
494 THE SUPAI GROUP OF GRAND CANYON

Section 34—Continued 

SEPARATION CANYON-Continued

Supai Group—Continued 

Manakacha Formation, slope unit—Continued 

Limestone, light-brownish-gray, fine-grained, 

very sandy to very silty (39 percent), 

medium-bedded (0.5-2 ft); contains irregular 

jasper lenses; weathers to dark-brown surface with sandy laminae etched in relief; 

cross-laminated near top; forms receding

Section 34—Continued 

SEPARATION CANYON-Continued

feet feet

Limestone, magnesian, medium-gray, finegrained, medium-bedded (0.5-2 ft); contains 

abundant lenses and nodules of jasper; forms 

ledge ———————————————————

Limestone, light-brownish-gray, very sandy 

(46 percent); cross-laminated on medium 

scale; forms ledge capping plateau —— ——— - 

Siltstone, pale-reddish-brown, shaly; contains few thin, reddish-brown sandstone 

beds; forms long slope overlying major cliff_ 

Total slope unit, Manakacha 

Formation —— ———— — ——— 

(Watahomigi Formation and cliff unit of Manakacha Formation measured in canyon 0.5 mile 

east of lava-capped mesa) 

Manakacha Formation, cliff unit:

Limestone, grayish-red, sandy (30 percent); 

medium-bedded (1-3 ft); cross-laminated at 

low angle and horizontally laminated; contains jasper concretions; weathers with 

etched, brown laminae; forms top of main

— 16.5

Limestone, medium-gray, medium-bedded

(1-3 ft); contains irregular jasper bands;

weathers to rough surface; forms rounded

ledge in cliff ———————————————

Limestone, grayish-pink, sandy; like cliff unit

above but cherty —————————————

Limestone, medium-gray, medium-bedded;

like jasper unit above ——————————

Limestone, grayish-pink, sandy; like lowangled, cross-laminated cliff unit at top ——— 

Limestone, medium-gray, medium-bedded;

like jasper-banded cliff unit at top —— ——— - 

Limestone, grayish-red, sandy (40 percent);

like low-angle, cross-laminated cliff unit at

Limestone, dolomitic, medium-gray, very fine 

grained; medium-bedded; like jasper-banded 

unit above; forms base of major cliff ——— —

Concealed slope ——————————————

5.0

6.0

27.0

95.0

11.0

5.0 

9.5 

8.5 

5.5 

5.0

11.0

10.0

17.5

Supai Group—Continued 

Manakacha Formation, cliff unit—Continued

Sandstone, medium-light-gray, very fine 

grained, some fine-grained, limy (44 

percent), thick-bedded (2-4 ft); locally contains many jasper layers and lenses; forms 

cliff with prominent parting; top bed crossstratified ———————————————————— 22.0

Siltstone, pale-reddish-brown, shaly; uniform 

in texture and structure; forms series of 

rounded ledges or a weak cliff, underlying 

major sandstone cliff ————————————— 23.0

Sandstone, pale-reddish-purple, very fine 

grained; contains dolomitic limestone (20 

percent); includes 1-ft reddish-brown mudstone parting; forms two resistant ledges —— 7.5

Limestone, pale-brownish-gray; granular; contains irregular jasper lenses; forms rounded 

ledge —————————————————————— 5.0

Limestone, pale-reddish-purple to purple, 

silty, sandy (insoluble 36 percent), resistant; 

medium-bedded (2-4 ft); cross-stratified on 

medium-scale; locally capped by few inches 

of fine-grained, pale-reddish-brown sandstone; forms ledge with straight face ————— 5.5

Siltstone, grayish-red-brown, shaly; locally 

contains mudcracks, ripple marks, burrows; 

beds progressively thicker near top; forms 

slope or weak ledges —————————————— 30.0

Mudstone, brownish-gray; intertonguing with 

dark-gray limestone; forms resistant ledge at 

cliff summit ——————————————————— 4.0

Siltstone, dark-reddish-brown, crumbly; forms

recess —

Limestone, light-gray, granular, thick-bedded; 

contains abundant jasper layers; forms resistant ledge ——————————————

Limestone, light-brownish-gray, aphanitic; 

contains many jasper layers (0.5-2 in. thick), 

some are parallel to bedding, others crosscut 

beds; weathers to rough surface, with vertical face; forms prominent marker —————

Limestone, pale-reddish-brown, very silty 

(48 percent), platy, flat-bedded; forms weak, 

rounded ledge beneath resistant cap rock ——_

2.0

9.0

6.5

7.5

Total cliff unit, Manakacha Formation —————————————205.0 

Total Manakacha Formation —— 300.0
MEASURED STRATIGRAPHIC SECTIONS 495

Section 34—Continued 

SEPARATION CANYON-Continued

Feet

Supai Group—Continued

Watahomigi Formation, upper slope unit: 

Concealed slope ————————————————— 46.0 

Total upper slope, Watahomigi

Formation ——————————— 46.0 

Watahomigi Formation, middle cliff and lower 

slope units:

Conglomerate, pale-gray and brown, locally 

crumbly; forms weak ledge —————————— 1.5 

Matrix: pale-gray to white silt. 

Gravel: closely packed; angular to subangular; jasper, white siltstone, quartz, 

red-brown mudstone, flint; average 

0.13-0.25 in. in diameter (maximum 1 

in.). 

Siltstone, grayish-red-brown, brittle; grains

with iron-oxide coatings, slope-forming ——— 2.0 

Limestone, pale-reddish-brown, silty (26 percent), platy, irregularly bedded; contains 

wavy beds of white chert; capped by bed of 

light-gray, fine-grained limestone —————— 3.5 

Mudstone, purplish-brown, very crumbly,

slope-forming ————————————————— 5.5 

Siltstone, light-brownish-gray, limy (30 percent); contains irregular jasper layers; 

weathers to brown surface; forms rounded, 

resistant ledge ————————————————— 7.0 

Concealed slope ————————————————— 4.5 

Limestone, brownish-gray, fine-grained, silty; 

contains abundant jasper layers; locally 

forms resistant ledge; weathers to rough, 

gray surface —————————————————— 4.5 

Concealed slope ————————————————— 4.0 

Siltstone, medium-light-gray, calcareous, thinbedded (6-12 in.); weathers dark-brown 

to black with thick laminae etched on surface; forms receding ledge ————————— 2.0 

Limestone, light-brownish-gray to pale-brown; 

includes much chert; contains fusulinids; 

forms resistant, rough ledge —————————— 3.0 

Concealed slope ————————————————— 6.5 

Limestone, light-gray, fine-grained; contains 

many thin jasper layers crosscutting bed in 

various directions; weathers to rough, gray 

surface; forms resistant ledge ————————— 3.0 

Concealed slope ————————————————— 5.5 

Limestone, yellow-brown, granular, mediumbedded (1-2 ft); contains abundant foraminifers(?); forms weak, rounded ledge or

Section 34—Continued 

SEPARATION CANYON-Continued

Supai Group—Continued 

Watahomigi Formation, middle cliff and lower

slope units—Continued

Limestone, grayish-orange-pink, fine-grained; 

contains much jasper near top; forms 

receding ledges ————————————

Limestone, light-gray to very light gray, finegrained, thick-bedded (2.5-4 ft); contains 

thin chert beds near top; fossiliferous (lowspired gastropod, conodonts); weathers 

brownish-gray; contains prominent parting 

bed in middle; forms major cliff ——————

Concealed slope ———————————————

Limestone, light-brownish-gray, aphanitic to 

fine-grained, massive, thick-bedded (2.5 ft); 

forms resistant ledge ————————————

Limestone, dolomitic, light-brownish-gray to 

grayish-orange-pink, aphanitic to finegrained; includes beds of white limestone 

breccia and bed with angular, purple 

mudstone fragments; thin- to mediumbedded (0.5-2 ft); contains beds with white, 

elongate spheres, in part hollow; forms slope 

with series of weak, receding ledges, mostly 

rounded ——————————————————

Limestone, grayish-red-purple, aphanitic with 

scattered granules throughout; mediumbedded (2.5-3 ft); includes parting zone of 

thin-bedded (0.5-2 in.) limestone; contains 

brachiopods (spiriferid, Composite) and fish 

tooth; weathers dark-gray; forms double 

ledge; prominent marker bed ————————

Limestone, grayish-red-purple, mediumgrained; weathers dark-gray, pitted; forms 

weak ledge ———————————————-

Claystone, pale-reddish-purple, fissile; forms 

slope; largely concealed ————————

Conglomerate, dark-reddish-brown, forms 

thin, resistant ledge ———————————

Matrix: gray and reddish-brown sandstone 

to gray, granular limestone.

Gravel: white and gray chert, white and red 

quartz; average diameters 0.25-0.5 in. 

(maximum 1.5 in.); angular to rounded, 

mostly subangular; very concentrated 

locally, elsewhere scattered; locally contains fossils (Composita, high-spired 

gastropod, spiriferid, pelecypod, fish 

tooth).

Feet

5.0

23.0 

7.5

2.5

33.0

6.5

— 3.0

5.5

2.5
496 THE SUPAI GROUP OF GRAND CANYON

Section 34—Continued 

SEPARATION CANYON-Continued

Feet

Supai Group—Continued 

Watahomigi Formation, middle cliff and lower 

slope units—Continued

Claystone, reddish-brown, structureless, 

weak, largely concealed ——————————— 7.0 

Total middle cliff and lower 

slope units, Watahomigi Formation —————————————151.0 

Total Watahomigi Formation — 197.0 

Unconformity:

Surface even and relatively flat with local 

mounds a few feet high; much concealed.

Total Supai Group exposed ——— 613.0 +

Redwall Limestone: 

Horseshoe Mesa Member: 

Limestone, light-olive-gray, aphanitic, 

medium-bedded; weathers to rough surface; 

forms receding ledges.

Section 35 

HINDU CANYON

[In eastern end of Hindu Canyon, south of Bridge Canyon, on small 

mesa at approximately sec. 24, T. 27 N., R. 12 E. and sec. 19, T. 27 N., R.

11 W.]

Feet

Top of mesa (recent erosion surface): 

Overlying red-slope member visible 0.5 mi to

north. 

Supai Group:

Watahomigi Formation:

Limestone, dark-gray, medium- to thickbedded (1-3 ft); contains many bands and 

crosscuts of jasper; forms cliff ———————— 13.0 

Limestone, pale-gray, aphanitic, thin-bedded 

(0.5-1 ft); forms weak, rounded, receding 

ledges —————————————————————— 10.0

thinLimestone, gray, medium-grained, mediumbedded (3 ft); weathers to rough, pitted surface; forms ledge ————————————————

Concealed slope —————————————————

3.0 

17.0

Section 35—Continued 

HINDU CANYON-Continued

Supai Group—Continued 

Watahomigi Formation—Continued 

Limestone, medium-gray, aphanitic,

bedded (0.5-1 ft); forms ledges ——————

Concealed slope ——————————————

Limestone, gray to purple, thin-bedded (0.5- 

1 ft); forms ledges ——————————————

Mudstone, deep-reddish-brown, structureless; 

rorms slope ———————————————————

Limestone, light-gray, fine-grained, thinbedded (0.5 ft); contains few, scattered pebbles of jasper; forms resistant ledge ————— 

Concealed slope ——————————————

Siltstone, pale-gray, shaly; alternating with 

reddish-brown, brittle, crumbly, structureless mudstone; forms slope —————————

Limestone, gray with reddish-brown blotches, 

silty, cross-stratified (tabular-planar); contains scattered pebbles of chert and jasper 

(0.13-0.25 in. in diameter); very fossiliferous 

with large local concentrations (brachiopods 

including Composite, Spirifer, Hustedial, 

gastropods, crinoids; fig. El); forms ledge — 

Mudstone, dark-reddish-brown, shaly; alternating with bright-reddish-brown, calcareous (42 percent), thin-bedded siltstone; 

forms slope ——————————————

Conglomerate, reddish-brown, forms massive ledge ——————————————————

Matrix: gray to reddish-brown, finegrained calcareous sandstone. 

Pebbles: gray limestone, abundant red jasper, yellow and white chert, black ironstone; subangular to well-rounded; 

average 0.25-0.5 in., maximum 1.5 in. in 

diameter.

Total Watahomigi Formation ——

Unconformity:

Assumed; contact not exposed. 

Redwall Limestone: 

Limestone, gray, aphanitic, massive; weathers to

rough, pitted surface; forms receding ledges.

Feet

3.0. 

12.0

3.0

3.0 

4.5

7.0

2.0

5.0 

4.5

92.5 +
INDEX

Aecretal, defined ............................................... 335

Accretal limestone, Watahomigi Formation ............ 345

Acknowledgments ............................................... 11

Age, determination ............................................. 15

Esplanade Sandstone .................................... Ill

Manakacha Formation .................................. 107

Pakoon Limestone ....................................... Ill

valley-fill deposits ........................................ 144

Watahomigi Formation .......................... 105, 115

Wescogame Formation ................................. 109

Algae ......................................... 24, 77, 99, 102, 179

Hermit Shale .............................................. 180

Manakacha Formation .................................. 335

Watahomigi Formation ........ 83, 144, 335, 346, 347

altirostris, Schizophoria ............... 80, 116, 122; pi. Fl

Aluminum .............................. 293, 297, 301, 308, 310

Amite River, Louisiana ...................................... 248

Ammobatrackus turbatans ................................... 92

Amphibians, tracks ..................................... 203,247

Wescogame Formation .................................. 25

amplus, Schizodus ............................ 120, 125; pi. F4

Amsden Formation, Wyoming ......... 117, 120, 122, 125

Anapiculatisporites concinnus ...................... 143, 144

Anaplanisporites globulus ........................... 143,144

Andrus Canyon ................................................. 144

conglomerate ............................................... 189

corrensite .............................................. 26, 327

cross-stratification ........................................ 223

dolostjne .................................................... 348

erosion surfaces .................................... 166, 167

evaporite deposits ........................................ 377

fish ............................................................ 121

grain size ................................................... 229

gypsum ..................................... 46, 48, 327, 377

Hermit Shale .............................................. 461

illite .............................. 24, 25, 26, 315, 325, 327

kaolinite ................................................ 26, 328

Pakoon Limestone ........................................ 49

petrography ......................................... 355, 357

ripple marks ............................................... 275

stratigraphic sections ................................... 461

vertebrate animals .................................. 91, 259

Anematina sp. .............................................. pi. G2

Anhydrite ......................................................... 377

Anomalopus sturdevanti ...................................... 92

Anomphalus sp. ................................................ 121

Anteridocus sp. ............................................. pi. F2

Anthracospirifer bifurcatus ................................. 115

chavezae ..................................................... 117

curvilateralis .................................... 144; pi. Gl

newberryi ............................. 80, 117, 122; pi. F3

ocridentalis ................................................. 190

occiduus ........ 70, 78, 80, 107, 117, 121, 122; pi. F3

opimus .................................................. 80, 117

tanoensis ....................... 80, 117, 121, 122; pi. F3

sp. ..................... 77, 85, 116, 117, 121, 189; pi. Gl

Apache Trail ............................. 35, 39, 171, 280, 427

Apeterrinella sp. ............................................... 346

Apterrinellids .................................................... 144

Arbuckle Mountains, Oklahoma ............................ 123

Arenaceous, defined ............................................ 10

Arizona sag ....................................................... 56

arizonae, Callipteris .......................................... Ill

Arrow Canyon, Nevada ............................... 108, 145

Asphaltina sp. .................................................. 144

Asteroarchaediscus sp. .................................. 83, 107

Athyridacea ...................................................... 117

[Italic page numbers indicate major references]

Page

Atoka Formation, Arkansas ................................ 123

Atokan conglomerate .............................. 40, 189, 190

Atokan Provincial Series ..................................... 194

Aubrey Cliffs .................................................. 3, 31

Aubrey Group ................................................. 3, 31

Aubrey Valley ...................................................... 3

Aubry Group. See Aubrey Group.

Auroraspora solisortus ................................ 143, 144

Authigenic, defined ............................................ 305

Aviculopecten gravidus ............... 120, 122, 125; pi. F4

sp. ................................................... 81, 82, 120

sp. A ......................................................... 120

sp. B ............................................... 120; pi. F4

B

Badger Canyon, erosion surface ........................... 171

Barnett Hill Formation, Oklahoma ....................... 123

Barytiehisma sp. ............................................... 143

Bashkirian Provincial Stage, Ural Mountains ......... 123

Bass Canyon ..................................................... 210

Bass Trail .................................................... 31, 1,18

carbonate mudstone ..................................... 344

conglomerate ............................................... 201

endothyra ................................................... 259

flora ........................................................... 98

fossils ........................................................ 203

grain size ................................................... 216

Hermit Shale .............................................. 418

ripple marks ............................................... 275

stratigrahic sections ..................................... £18

Bat Tower, buried valleys ................................... 139

fauna ......................................................... 144

foraminifera ................................................ 144

Battleship Wash Formation, Nevada .................... 145

Bay of Fundy .................................................... 258

Baylea sp. ........................................................ 121

Beaver Dam Mountains, Utah ...................... 107, 160

Beedeina sp. ..................................................... 108

Bellerophon sp. ......................... 81, 85, 121, 478, 480

bellerophontidae ........................................... 85, 121

bifurcatus, Anthracospirifer ................................ 115

Big Spring ........................................................ 109

Big Spring Canyon, fauna .................................... 70

fossils ......................................................... 69

Bijou Creek Flood, Colorado ............................... 254

Bioclastic, defined .............................................. 335

Bioclastic debris ......................................... 100, 338

Esplanade Sandstone ............................. 104, 259

Manakacha Formation ........................... 102, 259

Pakoon Limestone .................................. 26, 104

Watahomigi Formation ............... 23, 100, 259, 346

Wescogame Formation .......................... 103, 355

Biostratigraphy, Watahomigi Formation ................ 115

Bird Spring basin ............................................... 55

Bird Spring carbonate shelf .................................. 56

Bird Spring-Ely basin. See Cordillerian miogeosyncline. 

Bird Spring Range, fusulinids ............................... 72

Biseriamminds .................................................... 91

Bivalves ............................................................ 24

Esplanade Sandstone ............................. 104, 259

Manakacha Formation ........................... 102, 259

Pakoon Limestone ........................................ 26

Watahomigi Formation ............................ 23, 259

Wescogame Formation ..................... 25,103,259

Black Mesa basin ................................................ 57

Black Mesa sag ............................... 57, 102, 103, 182

Black River ............................................ 69, 70, 108

Bloyd Shale ............................................... 117, 126

Blue Mountain Canyon ....................................... 445

chert .......................................................... 200

conglomerate ........................... 114, 163, 189, 201

corrensite ................................................... 315

erosion surface ............................................ 171

fauna ......................................................... 203

fusulinids .................................................... 259

Hermit Shale .............................................. 445

kaolinite ..................................................... 328

Pakoon Limestone ........................................ 49

petrography ......................................... 347, 351

stratigraphic sections ................................... 445

Blue Spring ............................................... 340, 397

conglomerate ........................................ 191, 193

erosion surface ............................................ 171

Hermit Shale .............................................. 397

petrography ................................................ 350

shrinkage cracks .......................................... 276

stratigraphic sections ................................... 397

Bone Spring Limestone, New Mexico ................... Ill

Bostwick Conglomerate Member, Lake Murray

Formation ...................................... 123

Brachiopods, abundance ................................. 77, 105

Atokan conglomerate .................................... 191

buried-valley deposits ................................... 144

Esplanade Sandstone ............................. 104, 259

Manakacha Formation ............................. 85, 102

Pakoon Limestone ........................................ 89

Watahomigi Formation ............ 23, 65, 69, 70, 77,

84, 100, 105, U5,116, 122, 258, 346, 347, 363;

pis. Fl, F2, F3

Wescogame Formation ..................................103

Brachydactylopus ............................................... 92

Brazos River, Texas ................................... 249,256

Breezy Point ...................................................... 91

Brentwood Limestone Member of the Bloyd Shale . 117,

122, 123 

Bridge Canyon ........................................... 115,4%

brachiopods ................................................. 117

cephalopods ................................................ 121

faunas ........................................................ 123

gastropods .................................................. 121

jasper ........................................................ 374

pelecypods .................................................. 121

petrography ................................................ 347

Bright Angel Trail ............................................. 157

contorted stratification ................................. 280

cross-stratification ........................................ 234

erosion surface ............................................ 169

fossils ........................................................ 115

vertebrate animals .................................. 91, 259

Brucite ............................................................. 309

Bryozoans, abundance ......................................... 77

buried-valley deposits ................................... 144

Esplanade Sandstone .................................... 259

Manakacha Formation ...................... 85,102,259

Pakoon Limestone ............... 26, 89, 104, 182, 183

Watahomigi Formation ...................... 23, 82, 100,

115, 116, 122, 258, 346, 347 

Wescogame Formation .......................... 103,259

Bunker Trail ......................................... 40, 145, 401

conglomerate ............................. 41, 164, 193, 202

erosion surfaces .................................... 166, 171

foraminifers ................................................ 102

Hermit Shale .............................................. 401

pelmatozoans ............................................... 259

petrography ................................... 350, 355, 357

stratigraphic sections ................................... 401

497
498 THE SUPAI GROUP OF GRAND CANYON

Buried valleys ................................................... 139

Butter-field Peaks Formation, Utah ...................... 123

Buxtonia sp. ...................................... 70, 117; pi. Fl

Catamites .......................................................... 97

Calamospora sp. ............................................... 143

Calcispherids ........................................... 24, 85, 102

Calcite ................................................ 290, 291, 311

Calcium ............................ 50, 293, 301, 309, 312, 379

Calcivertella sp. ........................................... 89, 111

Callipteris arizonae ........................................... Ill

Callville Limestone ........................................ 31, 33

Callville Mountain ............................................... 31

Callville shelf ..................................................... 56

Cameron Creek Member, Tyler Formation ............ 122

campestris, Raticulariina ................................... 105

Canina sp. .................................................. 85, 111

Carbonate facies, distribution .............................. 338

Carbonate rocks ......................................... 303, 378

Esplanade Sandstone .................................... 384

Manakacha Formation .................................. S79

Pakoon Limestone ................................ 379, 384

Watahomigi Formation ................................. 379

Wescogame Formation .......................... 379, 384

Carrizo Creek ......................................... 69, 70, 109

Cataract Canyon .............................................. 4, 35

See also Havasu Canyon. 

Cataract Creek ..................................................... 4

Cavusgnathus gigantus ....................................... 84

Cedar Creek ........................................................ 3

Cedar Mesa Sandstone Member of the Cutler

Formation ...................................... 377

Cephalopods, Watahomigi Formation ............. 116, 121

Chainman Shale, Utah ........................................ 144

Channeling .......................................... 157, 160, 193

chavezae, Anthracospirifer .................................. 117

Chert, Atokan conglomerate ................................ 191

Blue Mountain Canyon ................................. 200

Esplanade-Pakoon conglomerate .............. 200, 358

Pakoon Limestone ....................................... 367

Watahomigi Formation ............. 190, 213, 344, 367

Wescogame Formation ................................. 193

Chinle, Arizona .................................................. 57

Chlorite ........................... 289, 293, 302, 305, 308, 309

Esplanade Sandstone ............................... 26, 328

Manakacha Formation ........................... 315,328

Watahomigi Formation ............................ 23, 315

Wescogame Formation ............................ 25, 325

Choliohnus gigas ................................................ 94

Cholla Bay, Mexico ............................................ 267

Circle Cliffs uplift ............................................... 55

clatriformis, Dictyotriletes ........................... 143, 144

Clay minerals .................................................... 289

associations ................................................. 305

depositional environments ............................. 305

distribution ................................................. 302

Esplanade Sandstone ............................. 326, 329

Manakacha Formation ........................... 315, 328

Pakoon Limestone ....................................... 326

Watahomigi Formation .......................... 314, 328

Clay minerals, Wescogame Formation ............ 324, 329

Claystone, defined .............................................. 11

clydensis, Inflatia ............................ 143; pis. Gl, G2

Coconino Sandstone ..................... 3, 31, 397, 399, 431

Coledium sp. .................................................... 117

Colorado Plateau ................................................ 64

Colorado River ...................................... 66, 248, 256

Composita elongata ....................................... pi. Gl

gibbosa .................... 77, 117, 121, 122, 144; pi. F2

ovata .................... 117, 121, 122, 144; pis. F2, Gl

subtilita ........................................... 117; pi. F3

sp. ............ 91, 116, 121, 189, 478, 496; pis. F3, G2

continnus, Anapiculatisporites ..................... 143, 144

Conglomerate beds ........... 107, 163, 171, 189, 201, 203

Conifers ........................................................... 179

Conodonts ......................................................... 77

Lime Ridge ................................................. 84

Page

Conodonts—Continued

Pakoon Ridge ............................................... 84

Separation Canyon .............................. 77, 83, 84

Conulariids, Watahomigi Formation ............ 77, 82, 116

Convolutisporaflorida ................................ 143, 144

sp. ............................................................. 143

Coral, abundance .......................................... 77, 105

buried-valley deposit .................................... 143

Esplanade Sandstone ............................... 69, 259

Granite Park ............................................... 143

Hidden Canyon ............................................ 85

Manakacha Formation ................................... 85

Pakoon Limestone ......... 26, 89, 104, 111, 182, 183

Parashant .................................................... 82

Toroweap .................................................... 82

Watahomigi Formation ... 70, 82, 115, 116, 125, 258 

Wescogame Formation ..................... 85, 111, 259

Cordarites ......................................................... 97

Cordilleran geosyncline ............................. 23, 25, 40,

55, 56, 67, 68, 351, 357 

deposits ............................................... 103, 201

Cordilleran miogeosyncline ......................... 55, 57, 66

Cordilleran negative belt ..................................... 55

Cordilleran seaway ....................... 102, 103, 104, 125,

181, 256, 352, 359, 377 

Cordilleran trough ........................................ 55, 338

Correlations, valley-fill deposits ........................... 144

Watahomigi Formation ................................. 122

Corrensite ....................... 289, 301, 303, 305, 308, 309

Andrus Canyon ...................................... 26, 327

Blue Mountain Canyon ................................. 315

Esplanade Sandstone ........................ 26, 311, 327

Grandview Trail .......................................... 315

Kaibab Trail, north ................................. 25, 325

Manakacha Formation ..................... 311, 315, 328

Separation Canyon .................................. 24, 315

Toroweap Point ............................................ 24

Watahomigi Formation ........ 23, 311, 315, 328, 363

Wescogame Formation ................................. 325

Cottonwood Canyon ........................................... 442

Cranaena sp. ................................................ pi. Gl

Crinoids, abundance ............................................ 77

Esplanade Sandstone .................................... 104

Watahomigi Formation ..................... 82, 100, 122

Wescogame Formation ................................. 103

Cross-bedding, Watahomigi Formation ................... 23

Cross-stratification ......................... 207, 209, 223, 247

Esplanade Sandstone .................. 26, 229, 249, 261

horizontal ................................................... 253

low-angle .................................................... 253

Manakacha Formation ......... 24, 216, 249, 256, 260

planar ........................................................ 249

small-scale .................................................. 256

See also ripple marks, 

trough ........................................................ 249

Watahomigi Formation .................... 211, 249, 260

Wescogame Formation ............... 25, 222, 249, 261

Crurithyris planiconvexa ................... 117, 122; pi. F2

Cumberland Plateau, Tennessee ........................... 311

Cupularostrum sp. ..................................... 117, 122

curvilateralis, Anthracospirifer ........................... 144

Cutler Formation ........................................... 92, 96

Cyanophyceae .................................................... 99

Cyclothems ....................................................... 184

Cystodictya sp. ................................................. 116

D

Defiance positive element ................ 25, 53, 57, 67, 68

Defiance uplift. See Defiance positive element.

Deoldus sp. .................................................. 83, 85

Deltodus mercurii .............................................. 122

sp. ...................................................... 121, 122

Deposition, Esplanade Sandstone .......................... 25

Wescogame Formation .................................. 24

Derbyia robusta ................................................ 117

sp. ....................................... 70, 80, 91, 107, 189

sp. A ............................................... 116; pi. Fl

Detrital, defined ................................................ 305

Diabolocera varieostatum Zone ............................ 123

Diagenetic, defined ............................................ 305

Diamond Creek, buried valleys ............................ 139

Dictyotriletes clatriformis ............................ 143, 144

Dielasmoid .................................................... pi. F2

Diplospkaerina sp. ............................................. 91

Ditomopyge sp. ................................................. 121

Dolostone .................................................... 26, 379

defined ........................................................ 11

Esplanade Sandstone ............................... 42, 384

Hidden Canyon ............................................ 26

Iceberg Canyon ............................... 26, 348, 379

Watahomigi Formation ................................. 348

Dotialdina sp. ................................................... 121

Dunbarinella sp. ................................................ 70

Dye Shale Member Bloyd Shale ........................... 123

E

East Verde River ......................................... 69, 108

eastoni, Linoproductus ....................................... 122

Echinoderms, abundance ...................................... 77

Esplanade Sandstone .................................... 104

Pakoon Limestone ........................................ 89

Watahomigi Formation ..................... 82, 116, 121

Edmondia sp. .................................... 82, 120; pi. F4

elongata, Composita ...................................... pi. Gl

Ely, Nevada ..................................................... Ill

Ely basin ........................................................... 55

Ely Limestone .................................................. 123

Ely-Bird Spring basin ......................................... 55

Emery uplift ...................................................... 53

Eminence Fault ................................................. 395

cross-stratification ........................................ 224

erosion surface ............................................ 171

fusulinids ............................................... 85, 259

Hermit Shale .............................................. 395

stratigraphic sections ................................... 395

Endothyra, Manakacha Formation ........................ 259

Endothyra excellens ........................................... 144

media ......................................................... 85

teres ........................................................... 85

sp. ........................................................ 91, 144

Endothyridae, Wescogame Formation .................... 87

English-metric conversion scale ............................ 11

Ensenada land .................................................... 55

Entletacea ........................................................ 116

Eoschubertella sp. ............................ 69, 85, 107, 474

Eosigmoilina explicata ....................................... 144

rugosa ....................................................... 144

equus, Hoplichnus .............................................. 94

Erosion surface, Esplanade Sandstone ..... 163, 165, 182

Hermit Shale ....................................... 169,202

Manakacha Formation ........................... 160, 182

Watahomigi Formation .......................... 157, 182

Wescogame Formation .......................... 160, 182

Esplanade Platform ............................................. 39

Esplanade Sandstone .............................. 5, 25, 35, 41

age ............................................................ Ill

bioclastic debris .................................... 104, 259

bivalves ............................................... 104, 259

brachiopods .......................................... 104, 259

bryozoans ................................................... 259

carbonate rocks ........................................... 384

chlorite ................................................. 26, 328

clay mineralogy .................................... 326,329

conglomerate ............................................... 194

corals .................................................... 69, 259

corrensite ....................................... 26, 311, 327

crinoids ...................................................... 104

cross-stratification ...................... 26, 229, 249, 261

deposition .................................................... 25

dolostone ............................................... 42, 384

echinoderms ................................................ 104

erosion surface ............................... 163, 165, 182

evaporite deposits ........................................ 260

flora .............................................. 98, 183, 241

foraminifers ................................... 104, 259, 358

fossils ................................................... 26, 241

fusulinids .................................................... 259
INDEX 499

Page

Esplanade Sandstone—Continued

gastropods .................................................. 259

geometry .................................................... 229

grain-size distribution ............................ 229, 261

gypsum ............ 26, 46, 69, 260, 261, 328, 358, 377

illite ...................................................... 26, 327

insoluble residues ........................................ 272

kaolinite ................................... 26, 314, 328, 329

lithology ...................................................... 48

marine fauna ............................................... 259

paleogeography ............................................ 67

pelmatozoans .................................. 105, 259, 357

petrography ................................................ 355

rain pits ..................................................... 277

ripple marks ........................................ 236, 241

vertebrate animals ........................................ 93

worm trails ................................................. 183

Euconospira sp. ................................................ 121

Euphemites sp. ................................................. 121

European equivalents ......................................... 123

Evaporite deposits ...................................... 309, 377

Esplanade Sandstone .................................... 260

excellens, Endothyra .......................................... 144

explicate, Eosigmoilina ...................................... 144

Fauna .............................................................. 258

distribution ............................................ 77, 181

Manakacha Formation ........................ 24, 85, 259

marine .................................................. 77, 181

Esplanade Sandstone .............................. 259

Pakoon Limestone ............................ 87, 183

Pakoon Limestone ........................................ 26

Watahomigi Formation ..................... 77, 115, 258

Wescogame Formation ................ 25, 85, 182, 259

variety ........................................................ 77

Fayetteville Shale, Arkansas and Oklahoma ........... 143

Feldspars .............................. 291, 303, 311, 312, 328

Fenestella sp. ............................................ 116, 122

Fenestrae, Watahomigi Formation ....................... 345

Fern ......................................................... 179, 182

buried-valley deposit .................................... 141

Festoons .......................................................... 256

Finke River, Australia ....................................... 254

Fish fossils, Watahomigi Formation ............... 116, 121

Fishtail Canyon ............................................ 24, 216

cross-stratification ........................................ 234

illite ........................................................... 315

kaolinite ................................................ 24, 324

ripple marks ............................................... 236

Flagstaff Limestone, Utah .................................. 363

Flaser bedding .................................................. 256

Flint, Watahomigi Formation ............................... 46

Flora .................................. 5, 97, 247, 258, 275, 357

Esplanade Sandstone ........................ 98, 183, 241

Hermit Shale .................................. 97, 111,202

Manakacha Formation ................................... 98

Pakoon Limestone ....................................... 183

Watahomigi Formation .................................. 97

Wescogame Formation .................................. 98

florida, Convolutispora ............................... 143, 144

Folk, R. L., quoted ........................................... 374

Foraminifers, Esplanade Sandstone ......... 104, 259, 358

Iceberg Canyon ...................................... 89, 111

Manakacha Formation ..................... 102, 182, 335

Pakoon Limestone ................................... 26, 89

valley-fill deposits .................................... pi. G3

Watahomigi Formation ..... 23, 70, 83, 84, 100, 144,

182, 259, 335, 344, 346, 347 

Wescogame Formation .................... 103, 182, 259

See also fusulinids. 

Fort Defiance ..................................................... 53

Fossil Bay, vertebrate animals ............................. 93

Fossil Creek, fossils ............................................ 69

Fossils .......................... 3, 69, 105, 182, 247, 258, 275

continental .................................................. 182

marine .................................................. 23, 258

Esplanade Sandstone ............................... 26, 241

Fossils—Continued

Hermit Shale .............................................. 202

Manakacha Formation ................................... 24

Pakoon Limestone ........................................ 26

Watahomigi Formation ......................... 3, 23, 46,

115, 182, 258, 346 

Wescogame Formation ............................ 25, 259

See also specific types of fossils. 

Four Corners ........................................... 24, 67, 72

Frenchman Mountain, Nevada ........... 71, 107, 160, 377

Fusulina sp. ................................................ 70, 108

Fusulinella sp. ....... 69, 77, 85, 107, 123, 407, 417, 477

Zone .......................................................... 123

Fusulinellids ...................................................... 77

Fusulinids, distribution ....................................... 105

Esplanade Sandstone .................................... 259

Manakacha Formation ..... 24, 69, 85, 104, 182, 259

Pakoon Limestone ................. 26, 70, 89, 111, 183

Watahomigi Formation ................ 23, 69, 105, 259

Wescogame Formation .... 25, 67, 85, 111, 182, 259

Gastropods, abundance ........................................ 77

buried-valley deposits ................................... 144

Esplanade Sandstone .................................... 259

Manakacha Formation ................................... 85

Pakoon Limestone .................................. 89, 183

Watahomigi Formation ...................... 80, 84, 115,

120, 258, 346; pi. F4 

Wescogame Formation ............................. 25, 85

Geinitzina sp. .............................................. 89, 111

gibbosa, Composite ......... 77, 117, 121, 122, 144; pi. F2

gigantus, Cavusgnathus ...................................... 84

gigas, Choliohnus ............................................... 94

Girvanella ...................................... 24, 102, 346, 347

Glabrodngulum quadrigatum .......................... pi. G2

sp. ............................................................. 144

globulus, Anaplanisporites .......................... 143, 144

Goddard Formation, Oklahoma ............................ 144

Goddard Shale Member, Goddard Formation ......... 144

Golf Course Formation, Oklahoma ........................ 123

Gomti River, India ............................................ 256

gonionota, Reticulariina ..................................... 117

gracilis, Scoyenia ....................................... 100, 180

Grain-size distribution ................................. 208, 257

Esplanade Sandstone ............................. 229, 261

Manakacha Formation .................................. 216

Watahomigi Formation ............. 211, 344, 345, 347

Wescogame Formation .......................... 222, 261

Grain types, defined ........................................... 335

Grand Gulch Mine ....................................... 471, 479

flora ........................................................... 98

Hermit Shale .............................................. 479

Pakoon Limestone ....................................... 481

stratigraphic sections ................................... 479

Grand Wash Cliffs .............................. 31, 46, 48, 384

brachiopods .................................................. 80

carbonate rocks ........................................... 384

cyclothems .................................................. 186

evaporite deposits ........................................ 377

marine faunas ........................................ 88, 259

megafossils .................................................. 85

Pakoon Limestone ........................................ 49

petrography ................................................ 355

warping ...................................................... 145

Grand Wash fault .............................................. 201

Grandview Trail ........................ 40,49,160,241,404

bivalves ...................................................... 259

corrensite ................................................... 315

cross-stratification ................................. 223, 234

foraminifers ......................................... 102, 182

fusulinids ........................................ 85, 107, 259

Hermit Shale .............................................. 404

Redwall Limestone ............................... 341, 407

stratigraphic sections ................................... 404

Granite Park, algae ............................................ 144

buried valleys ...................................... 139, 145

corals ......................................................... 143

Granite Park—Continued

foraminifera ................................................ 144

Granite Park valley ............................................ 139

Granulatisporites granulatus .............................. 143

sp. ............................................................. 143

granulatus, Granulatisporites ............................. 143

Grassy Mountain ............................................... 461

gravidus, Aviculopecten .............. 120, 122, 125; pi. F4

Great Basin ....................................................... 72

fauna ......................................................... 121

fusulinids .................................................... 107

Guano Cave ................................................. 40, 468

accretal limestone ........................................ 346

brachiopods ................................................. 117

cephalopods ................................................ 121

conglomerate ........................................ 190, 191

fauna ......................................................... 122

marine ................................................. 259

fish ............................................................ 121

gastropods .................................................. 121

mineralogy .................................................. 348

molluscs ...................................................... 91

ostracodes .................................................. 346

pelecypods ............................................. 85, 120

petrography ......................................... 347, 355

ripple marks ............................................... 275

sharks teeth ................................................. 83

stratigraphic sections ................................... 468

Gypsum ........................................... 3, 290, 291, 311

Andrus Canyon .......................... 46, 48, 327, 377

Esplanade Sandstone ............................... 26, 46,

69, 260, 261, 328, 358, 377 

Parashant Canyon .............................. 46, 48, 377

Shivwitz Plateau ........................................... 46

Toroweap Valley ............................... 46, 48, 377

H

Hack Canyon, erosion surface .............................. 169

Hadrohercos stereon .................................... 143, 144

Hale Formation .......................................... 122, 123

Halgaito Tongue ................................................. 96

Halite .............................................................. 377

Hardinsburg Formation, Illinois ........................... 144

Havasu Canyon ............................................. 4, 427

accretal grains ............................................. 344

algae .......................................................... 182

bivalves ...................................................... 259

brachiopods ............................................ 77, 258

carbonate mudstone ..................................... 344

channels .............................................. 193, 195

channel-fill .................................................. 164

conglomerate .......... 42, 46, 163, 189, 191, 193, 201

contorted stratification ................................. 280

cross-stratification ................................. 216, 223

erosion surface .......................... 42, 160, 163, 171

foraminifers ................................................ 344

fossils ........................................................ 115

Hermit Shale .............................................. 427

kaolinite ................................................ 24, 324

mineralogy .................................................. 345

Pakoon Limestone ........................................ 49

pelmatozoans ............................................... 344

ripple laminae ...................................... 213, 275

stratigraphic sections ................................... 427

surfaces of erosion ........................................ 40

type locality ................................................. 35

Havasupai Point, erosion surface ................... 169, 202

Hedraittes sp. ................................................... 346

Hematite ............................................. 290, 291, 328

Hermit Canyon, erosion surfaces ............. 169, 171, 202

Hermit Shale ............................ 3, 27, 31, 46, 68, 247

algae .......................................................... 180

Andrus Canyon ........................................... 461

Bass Trail ................................................... 418

Blue Mountain Canyon ................................. 445

Blue Spring ................................................ 397

Bunker Trail ............................................... 401

conglomerates ............................................. 203
500 THE SUPAI GROUP OF GRAND CANYON

Hermit Shale—Continued

Eminence Fault ........................................... 395

erosion surface ..................................... 169, 202

flora .............................................. 97, 111, 202

fossils ........................................................ 202

Grand Gulch Mine ........................................ 479

Grandview Trail .......................................... 404

Havasu Canyon ........................................... 427

Hermit Trail ............................................... 414

Hidden Canyon .................................... 483,486

Horsetrail Canyon ....................................... 400

Iceberg Canyon ........................................... 487

Kaibab Trail, north ...................................... 411

Kaibab Trail, south ...................................... 407

Kanab Canyon ............................................. 436

National Canyon .......................................... 431

Parashant Canyon ........................................ 458

Prospect Valley ........................................... 447

ripple marks ............................................... 275

S B Canyon ................................................ 438

Seligman .................................................... 492

Shinumo Trail ............................................. 422

Snap Canyon ............................................... 471

Thunder River Trail ..................................... 423

Tqpocoba Trail ............................................ 426

Toroweap Valley ......................................... 449

Tuckup Canyon ........................................... 442

Twentynine Mile Canyon .............................. 391

Twin Springs Canyon ................................... 464

Whitmore Wash .......................................... 457

Hermit Trail .................................... 31, 49, 247, 4U

bioclasts ..................................................... 259

carbonate mudstone ..................................... 344

channels ..................................................... 193

chlorite ...................................................... 328

conglomerate ............................................... 193

cross-stratification ........................................ 256

erosion surface ............................................ 171

flora .............................................. 97, 111, 182

fossils ................................................. 183, 203

fusulinids ............................................... 85, 259

grain size ............................................ 216,222

Hermit Shale .............................................. 414

kaolinite ..................................................... 328

mineralogy .................................................. 345

pelmatozoans ............................................... 100

rain pits ........................................ 182, 203, 277

shrinkage cracks ................................... 182, 203

strata .................................................... 40, 182

stratigraphic sections ................................... 414

vertebrate animals .................................. 91, 259

heterofiliferous, Punctatisporites .......................... 143

Hidden Canyon .............. 40, 46, 48, 163, 481, 483, 486

accretal limestone ........................................ 346

bryozoan .................................................... 116

carbonate rocks ........................................... 384

channels .............................................. 164, 195

conglomerates ...................................... 195, 201

corals .......................................................... 85

cross-stratification ................................. 256, 258

dolostone ..................................................... 26

fauna .................................................. 122, 259

flora ..................................................... 98, 183

foraminifers ................................................ 183

fusulinids ............................................... 85, 111

gastropods ................................................... 85

grain size ............................................ 216,222

Hermit Shale ....................................... 483,486

illite ........................................................... 327

insoluble residue .......................................... 272

marine faunas ........................................ 88, 259

marine fossil ................................................ 85

mineralogy .................................................. 348

Pakoon Limestone ....................................... 483

pelecypods .................................................. 120

petrography ............................ 347, 351, 352, 355

sharks teeth ................................................. 85

stratigraphic sections ...................... 481, 483, 486

vertebrate fragments ................................... 346

Hindu Canyon ............................................ 213,400

stratigraphic sections ................................... 496

History ........................................................ 3, 247

Hogan basin ..........................................••••••••••••• 55

Holbrook basin ........................................... 260, 377

Hoplichnus equus ............................................... 94

Horseshoe Mesa Member of the Redwall Limestone.. 115

Andrus Canyon ........................................... 464

Bass Trail ................................................... 421

Blue Mountain Canyon ................................. 447

Blue Spring ................................................ 399

Bunker Trail ............................................... 404

Eminence Fault ........................................... 397

Grandview Trail .......................................... 407

Guano Cave ................................................ 471

Havasu Canyon ........................................... 431

Hermit Trail ............................................... 418

Hidden Canyon ........................................... 483

Iceberg Canyon ........................................... 492

Kaibab Trail, north ...................................... 414

National Canyon .......................................... 436

Pigeon Wash ............................................... 479

S B Canyon ................................................ 441

Separation Canyon ....................................... 496

Snap Canyon ............................................... 475

Thunder River Trail ..................................... 426

Toroweap Valley ......................................... 453

Tuckup Canyon ........................................... 444

Twentynine Mile Canyon .............................. 395

Twin Springs Canyon ................................... 468

Whitmore Wash .......................................... 457

Horsetrail Canyon ............................................. 399

channels ..................................................... 193

conglomerate ............................................... 193

erosion surface ............................................ 171

Hermit Shale .............................................. 400

stratigraphic sections ................................... 399

Horton group, Nova Scotia ................................. 144

House Rock Canyon .................................... 183, 391

ripple marks ............................................... 236

stratigraphic sections ................................... 391

House Rock Rapids ............................................ 165

Hualapai Trail .................................. 35, 39, 213, 280

Hundred and Fifty Mile Canyon .......................... 438

Hustedia miseri ................................................. 70

sp. ............................................................. 4%

I

Iceberg Canyon ................. 31, 40, 46, 48, 49, 163, 487

carbonate rocks .................................... 379,384

conglomerate ........................................ 200, 201

contorted stratification ................................. 280

cross-stratification ................................. 256, 258

cyclothems .................................................. 186

dolostone ........................................ 26, 348, 379

fauna ......................................................... Ill

flora ..................................................... 98, 182

foraminifers ........................................... 89, 111

Hermit Shale .............................................. 487

illite........................................................... 327

insoluble residue .......................................... 272

marine faunas .............................................. 88

mineralogy .................................................. 348

Pakoon Limestone ....................................... 488

petrography ......................................... 347, 355

ripple marks ............................................... 275

sediments ................................................... 184

sharks teeth ................................................. 85

stratigraphic sections ................................... 487

Ichnite fauna, Wescogame Formation .................... 92

Illite ........... 289, 293, 297, 303, 305, 308, 309, 311, 379

Andrus Canyon .............. 24, 25, 26, 315, 325, 327

Esplanade Sandstone ............................... 26, 327

Fishtail Canyon ........................................... 315

Hidden Canyon ........................................... 327

Iceberg Canyon ........................................... 327

Kaibab Trail, north .......................... 25, 315, 325

Manakacha Formation ................ 24, 315, 328, 364

Illite—Continued

Pakoon Limestone ....................................... 327

Watahomigi Formation ............................ 23, 363

Wescogame Formation ............................ 25, 324

Illite-smectite clays ..................................... 289, 297

incertus, Neoarchaediscus .............................. 83, 107

Indian Springs Formation, Nevada ....................... 145

Indus River ..........."........................................... 256

Inflatia dydensis ............................. 143; pis. Gl, G2

sp. ............................................................. 144

Iron .......................................................... 297, 312

Isotope analyses ................................................ 363

Jasper .............................................................. 367

age ............................................................ 374

Atokan conglomerate .................................... 191

Esplanade-Pakoon conglomerate .............. 200, 374

Manakacha Formation .............. 258, 351, 367, 374

origin ......................................................... 372

Parashant Canyon ........................................ 374

petrology .................................................... 369

Separation Canyon ....................................... 200

Toroweap Valley ......................................... 374

Watahomigi Formation ............................ 40, 46,

213, 344, 346, 367, 374 

Wescogame Formation .......................... 193, 374

Jasperoid, defined .............................................. 367

Johns Valley Shale ............................................. 123

Jump Canyon .................................................... 486

K

Kaibab Limestone ................................................. 3

Kaibab Plateau ................................................... 55

Kaibab Trail, flora ............................................. Ill

silica rock ................................................... 367

strata .......................................................... 40

Kaibab Trail, north ..................................... 241,411

accretal grains ............................................. 344

channel-fill ........................................... 164, 195

chlorite ...................................................... 328

conglomerate ........................................ 164, 195

contorted bedding ........................................ 221

contorted stratification ................................. 280

corrensite .............................................. 25, 325

cross-stratification ................................. 223, 258

flora ........................................................... 98

fusulinids ........................................ 85, 107, 259

Hermit Shale .............................................. 411

iUite ............................................... 25, 315, 325

mineralogy .................................................. 345

pelmatozoans ............................................... 259

rain pits ..................................................... 277

Redwall Limestone ...................................... 414

ripple marks ............................................... 275

shrinkage cracks .......................................... 276

stratigraphic sections ................................... 411

surfaces of erosion ........................................ 40

vertebrate animals .................................. 91, 259

Kaibab Trail, south ................................ 49, 203, 407

algal accretions ............................................ 344

bivalves ...................................................... 259

conglomerate ............................................... 193

cross-stratification ................................. 210, 234

erosion surface ............................................ 171

flora .............................................. 97, 182, 203

Hermit Shale .............................................. 407

isotope analyses ........................................... 363

Redwall Limestone ............................... 341, 411

stratigraphic sections ................................... 407

vertebrate animals .................................. 91, 259

Kaibab uplift ...................................................... 55

Kanab Canyon ............................................... 3, 436

channels ..................................................... 195

cross-stratification ................................. 216, 223

erosion surface ............................... 160, 164, 169

Hermit Shale .............................................. 436
INDEX 501

Page 

Kanab Canyon—Continued

stratigraphic sections ................................... 436

Kaolinite ......................... 289, 291, 303, 305, 308, 311

Andrus Canyon ...................................... 26, 328

Blue Mountain Canyon ................................. 328

Esplanade Sandstone .................. 26, 314, 328, 329

Fishtail Canyon ...................................... 24, 324

Havasu Canyon ...................................... 24, 324

Hermit Trail ............................................... 328

Manakacha Formation ..................... 315, 329, 364

Prospect Valley ...................................... 26, 328

Watahomigi Formation ..................... 23, 315, 363

Wescogame Formation ..................... 25, 325, 364

Karsts ....................................................... 157, 159

kaskaskiensis, Orthotetes .................................... 115

Kayenta, Arizona ................................................ 57

Kessler Limestone Member, Bloyd Shale .............. 123

Knoxisporites triradiatus ............................. 143, 144

Kohls Ranch ................................................ 69, 108

Kosanke, R. M. quoted ....................................... 144

La Pasada Formation, New Mexico ...................... 123

Lake Mead ........................................................ 31

Lake Bonneville ................................................ 363

Lake Murray Formation, Oklahoma ...................... 123

Lake Point Limestone, Utah ............................... 123

Las Vegas Hinge Line ......................................... 56

Lenticular bedding ............................................. 256

Leptodesma sp. ................................................. 120

Lime Ridge, conodonts ........................................ 84

Limestone, aphanitic ................................... 338, 341

linearis, Schwagerina. ......................................... Ill

Lingula sp. .................................................. 16, 452

Linoproductus eastoni ........................................ 122

nodosus ............... 68, 70, 80, 107, 117, 122; pi. Fl

Zone ............................................. 107, 122

pumttus ............................... 80, 117, 122; pi. Fl

sp. ........................................................ 91, 190

sp. A ............................................ 117, 121, 122

Lipan Point ...................................................... 401

Liroceros sp. ..................................................... 121

Lithology ........................................................... 46

buried-valley deposits ................................... 139

Esplanade Sandstone ..................................... 48

Manakacha Formation .............................. 26, 46

Watahomigi Formation ....................... 23, 46, 157

Wescogame Formation .................................. 47

Little Colorado River Gorge ................................ 401

Lovering, T. G., quoted ...................................... 370

Lower Cook Inlet .............................................. 258

Lycospora spp. .................................................. 143

M

Magnesium ............................ 297, 309, 310, 312, 379

Magnesium carbonate, Pakoon Limestone ............... 50

Manakacha Formation .................................... 35, 40

age ............................................................ 107

bioclastic debris .................................... 102, 259

bivalves ............................................... 102, 259

brachiopods ............................................ 85, 102

bryozoans ....................................... 85, 102, 259

carbonate rocks ........................................... 379

chlorite ............................................... 315, 328

clay mineralogy .................................... 315,328

contorted stratification ................................. 280

coral ........................................................... 85

corrensite ...................................... 311, 315, 328

cross-stratification ............... 24, 216, 249, 256, 260

cyclothems .................................................. 186

endothyra ................................................... 259

environment of deposition ............................. 260

erosion surface ..................................... 160, 182

fauna ............................................... 24, 85, 259

flora ........................................................... 98

foraminifers ................................... 102, 182, 335

fossils ......................................................... 24

Manakacha Formation—Continued

fusulinids ....................... 24, 69, 85, 104, 182, 259

gastropods ................................................... 85

grain-size distribution ................................... 216

history ........................................................ 23

illite ......................................... 24, 315, 328, 364

insoluble residues ........................................ 265

isotopic data ............................................... 363

jasper .................................... 258, 351, 367, 374

kaolinite ................................. 314, 315, 329, 364

lithology ................................................. 24,46

marine fauna .......................................... 85, 260

paleogeography ............................................ 65

pelmatozoans ........................................ 102, 259

petrography ................................................ 348

rain pits ..................................................... 277

ripple marks .................................. 220, 260, 275

sandstone ................................................... 213

silica rock ................................................... 367

Manakacha Point ................................................ 35

Manzano fossils .................................................. 53

Marble Canyon .................................................. 391

clay mineralogy ........................................... 315

erosion surface ..................................... 165, 171

petrography ................................................ 355

ripple marks ........................................ 236,275

stratigraphic sections ................................... 391

Marcon, Jules, quoted ........................................... 3

Marine fauna ...................................................... 77

Esplanade Sandstone .................................... 259

Pakoon Limestone ........................................ 87

Manakacha Formation ............................. 85, 260

Pakoon Limestone .................................. 87, 183

Watahomigi Formation ............... 77, 189, 258, 260

Wescogame Formation ..................... 85, 259, 261

Mazatzaland ....................................................... 56

media, Endothyra .............................................. 85

meekana, Orbicubidea ....................... 116, 122; pi. Fl

Meekospira sp. .................................................. 121

Megaripples .................................. 247, 249, 258, 260

mercurii, Deltodus ............................................. 122

Mexican geosyncline ............................................ 56

Michelinia sp. ......................................... 70, 82, 143

Micrite, defined .................................................. 11

Watahomigi Formation .......................... 258, 347

Microdoma sp. ........................................ 121; pi. F4

Microfauna, Watahomigi Formation ....................... 83

Mile 16. See House Rock Canyon.

Millerella sp. ..................................................... 70

miseri, Hustedia ................................................ 70

Mississippi River ........................................ 249, 256

missouriensis, Orbiculoidea ................................ 116

Moenkopi Formation, ripple marks ....................... 275

Mogollon Rim ..................................................... 58

fossils ......................................................... 69

Mollusks, Watahomigi Formation ....... 84, 121, 182, 347

Wescogame Formation ............................ 85, 259

Monosaccates .................................................... 143

Montmorillonite ............................. 289, 303, 310, 315

Monument Valley ............................................... %

Mormon Mountains, fusulinids .............................. 72

Morrow Formation, Oklahoma ............................. 144

Mountain Spring Pass, Nevada ..................... 108, 160

Muav Canyon .................................................... 422

Mud cracks ................................................ 247, 275

Muddy Mountains ............................................... 31

evaporite deposits ........................................ 377

multattenuata, Syringopora ........................... 85, 111

Muscovite .................................................. 345, 355

Myalina sp. .................................... 81, 122, 479, 482

sp. A ............................................... 120; pi. F4

sp. B ............................................... 122; pi. F4

N

Naco Group ....................................................... 58

Naco Formation ................................................. 70

Naticopsis sp. ............................................ 121, 479

National Canyon .................................... 40, 115, 431

apharitic limestone ....................................... 341

Page

National Canyon—Continued

brachiopods .................................... 117, 258, 363

carbonate mudstone ..................................... 344

channels ..................................................... 195

conglomerate .. 42, 163, 189, 191, 193, 195, 201, 202 

corrensite ................................................... 315

erosion surface .......................... 42, 160, 163, 171

faunas ........................................................ 123

gastropods .................................................. 121

Hermit Shale .............................................. 431

jasper ................................................. 200,374

mineralogy .................................................. 345

Pakoon Limestone ........................................ 49

pelecypods ........................................... 120, 121

petrography ......................................... 347, 351

ripple structures ................................... 213, 275

stratigraphic sections ................................... 431

trilobites .................................................... 121

Nautiloids, Watahomigi Formation ........................ 82

Navajo Falls ..................................................... 427

Neilsonia sp. ................................................ pi. G2

Neoarchaediscus incertus ............................... 83, 107

parvus .................................................. 83, 107

spp. ........................................................... 144

Neospirifer ....................................................... 478

Neuroptfris ....................................................... 97

nevadensis, Rhipidomella .................................... 70

Newberry, J. S., quoted ........................................ 3

newberryi, Anthracospirifer .......... 80, 117, 122; pi. F3

New Red Sandstone, Scotland .............................. 94

nitidus, Punctatisporites .................................... 143

nodosus, Linoproductus ............................ 69, 70, 80,

107, 117, 122; pi. Fl 

North Bird Spring Range, Nevada ....................... 160

North Virginia Mountains, Nevada ....................... 108

Nuculopsis sp. ........................................ 120; pi. F4

0

Oak Creek, correlation with Supai Group ............... 69

occidentalis, Anthracospirifer .............................. 190

occiduus, Anthracospirifer ........................ 70, 78, 80,

107, 117, 121, 122, pi. F4 

Oncolites ................................................... 335, 338

O'Neill Butte ..................................................... 91

Ooids ........................................................ 335, 338

opimus, Anthracospirifer ............................... 80, 117

Oquirrh Basin .................................................... 72

Oquirrh Group .................................................. 123

Oquirrh Mountains ............................................. 123

Orbiculoidea meekana ....................... 116, 122; pi. Fl

missouriensis .............................................. 116

sp. ............................... 70, 80, 115, 452, 479, 480

Organ Rock Tongue ............................................ %

Oriocrassatella sp. ............................................. 120

Orthotetes kaskaskiensis ..................................... 115

sp. ........................................................ 80, 116

sp. A ............................................... 116; pi. Fl

Ortonella sp. ..................................................... 144

Osagia sp. ................................................. 181, 346

Ostracodes, buried-valley deposits ........................ 144

Watahomigi Formation ................................. 346

Ouachita Mountains ............................................ 123

Ouachita trough, Oklahoma ................................. 125

ovata. Composite .......... 117, 121, 122, 144; pis. F2, Gl

Ovatia sp. .................................................... pi. G2

Overbrook Sandstone Member, Springer Formation.. 144 

Ozawaiwlla sp. ....................................... 72, 85, 111

Pakoon Limestone ...................... 5, 26, 31, 42, 44, 49

age ............................................................ Ill

Andrus Canyon ............................................ 49

bioclastic debris ...................................... 26, 104

bivalves ....................................................... 26

Blue Mountain Canyon .................................. 49

brachiopods .................................................. 89

bryozoans ........................... 26, 89, 104, 182, 183
502 THE SUPAI GROUP OF GRAND CANYON

Page 

Pakoon Limestone—Continued

carbonate rocks .................................... 379, 384

chert .......................................................... 367

clay mineralogy ........................................... 326

conglomerate ............................................... 194

contorted stratification ................................. 280

corals ........................... 26, 89, 104, 111, 182, 183

definition ..................................................... 33

echinoderms ................................................. 89

erosion surface ............................................ 182

fauna .......................................................... 26

flora .......................................................... 183

foraminifers ............................................ 26, 89

fossils .................................................rZTr.. 26

fusulinids .............................. 26, 70, 89, 111, 183

gastropods ............................................. 89, 183

Grand Gulch Mine ........................................ 481

Grand Wash Cliffs ........................................ 49

Guano Cave ................................................ 468

Havasu Canyon ............................................ 49

Hidden Canyon ........................................... 483

Iceberg Canyon ........................................... 488

illite ........................................................... 327

isoluble residues .......................................... 272

magnesium carbonate .................................... 50

marine fauna .......................................... 87, 183

marine fossils ............................................... 26

paleogeography ............................................ 67

pelmatozoans .......................................... 26, 105

petrography ................................................ 355

Pigeon Wash ............................................... 475

sharks teeth ........................................... 89, 183

Snap Canyon ............................................... 472

worm trails ................................................. 183

Pakoon Ridge ............................................... 33, 108

conodonts .................................................... 84

correlation ................................................... 71

evaporite deposits ........................................ 377

fusulinids ..................................................... 72

Paladin sp. ..................................... 121, 122; pi. G2

Palaeoneilo sp. ................................................. 120

Paleogeography ............................................... 5, 65

Esplanade Sandstone ..................................... 67

Pakoon Limestone ........................................ 67

Watahomigi Formation ............................ 57, 125

Paleyoldia sp. ................................................... 120

Palynomorphs, buried-valley deposit ..................... 143

Panorama ............................................................ 4

Paradox basin ............................... 40, 55, 56, 67, 68,

72, 102, 103, 182, 351, 352 

Paradox sea ....................................................... 57

Parashant Canyon .............................................. £58

Parashant Canyon, bryozoans .............................. 116

conglomerate .......................................... 47, 189

conifers ...................................................... 182

contorted stratification ................................. 280

corals .......................................................... 82

cross-stratification ........................................ 223

erosion surface ............................................ 171

evaporite deposits ........................................ 377

fish ............................................................ 121

flora ..................................................... 98, 111

fossils ........................................................... 3

fusulinids ............................................... 85, 259

gypsum ............................................ 46, 48, 377

Hermit Shale .............................................. 458

jasper ........................................................ 374

petrography ................................................ 358

sediment .................................................... 184

sharks teeth ................................................. 83

stratigraphic sections ................................... 458

vertebrate animals .................................. 91, 259

Partidge Creek ..................................................... 3

parvus, Neoarchaediscus ............................... 83, 107

Pedregosa basin ................................................. 56

Pelecypods, abundance ........................................ 77

Manakacha Formation ............................. 85, 102

Watahomigi Formation ...................... 81, 84, 100,

115, 116, 120, 182, 258; pi. F4 

Wescogame Formation ................ 25, 85, 103, 259

Pelmatozoans ..................................................... 24

buried-valley deposits ................................... 144

Esplanade Sandstone ....................... 105, 259, 357

Manakacha Formation ........................... 102, 259

Pakoon Limestone .................................. 26, 105

Watahomigi Formation . 23, 100, 259, 344, 346, 347 

Wescogame Formation ............... 25, 103, 259, 355

Peloidal, defined ................................................ 335

permiensis, Rivularites ...................................... 100

Permophorus sp. ................................ 82, 120; pi. F4

Petrography ...................................................... 335

Esplanade Sandstone .................................... 355

Manakacha Formation .................................. 348

Pakoon Limestone ....................................... 355

Wescogame Formation ................................. 352

Phestia sp. ............................................. 120; pi. F4

Phricodothyris .................................................. 478

Pica, fauna ........................................................ 80

pelecypods .................................................. 120

Watahomigi Formation ................................. 372

Picaeho Butte, grain size .................................... 229

picuris, Pulchratia ........................... 117, 122; pi. Fl

Pigeon Wash ...................................... 33, 40, 48, 475

accretal limestone ........................................ 338

brachiopods ............................................ 85, 191

carbonate rocks ........................................... 384

conglomerate ........................................ 191, 201

fusulinids ........................................ 85, 107, 111

grain size ................................................... 222

jasper ........................................................ 372

marine faunas ........................................ 88, 259

Pakoon Limestone ....................................... 475

petrography ......................................... 351, 355

ripple marks ............................................... 183

sediment .................................................... 184

shrinkage cracks ................................... 183, 276

stratigraphic sections ................................... 475

worm trails ................................................. 183

Pioche basin .................................................. 55, 72

Pisolites .................................................... 335, 338

Piute positive element ............................... 55,66,67

planiconvexa, Crurithyris .................. 117, 122; pi. F2

Platte River ............................................... 248, 250

plicatulw, Triticites ........................................... 72

Point Sublime ...................................................... 4

Polypora sp. ..................................................... 116

Potassium .............................. 293, 301, 308, 309, 312

Potassium feldspar ................................ 291, 313, 328

Powell, J. W., quoted ............................................ 3

Profusulinella ....................................... 87, 107, 123

Zone .......................................................... 123

Promytilus sp. ................................. 120, 122; pi. F4

Prospect Valley ................................................. 447

erosion surface ............................................ 171

Hermit Shale .............................................. 447

insoluble residue .......................................... 272

kaolinite ................................................ 26,328

petrography ................................................ 357

stratigraphic sections ................................... 447

Pseudoconocardium sp. ...................................... 120

Pseudoendothyra sp. ........................................... 91

Pseudoglomospira sp. ........................................ 144

psendolevalus, Punctatisporites ........................... 143

Pseudoschwagerina sp. ........................ 70, 71, 89, 111

Pseudostaffella, sp. ..................... 69, 85, 107, 407, 413

Pulchratia picuris ............................ 117, 122; pi. Fl

pumilus, Linaproductus ............... 80, 117, 122; pi. Fl

Punctatisporites heterofiliferous ........................... 143

nitidus ....................................................... 143

pseudolevatus .............................................. 143

solidus ................................................ 143, 144

validus ....................................................... 143

spp. ........................................................... 143

Punctospirifer transversus 80, 105, 117, 121, 122; pi. F3 

sp. ................................................. 70, 190, 478

quadrigatum, Glabrocingulum ......................... pi. G2

Quartermaster Canyon, buried valleys ........... 139, 145

Page

Quartz ............................ 11, 182, 189, 291, 303, 308,

311, 344, 347, 355, 357, 372 

Quartz sandstone ................................... 44, 104,207

Quartzite ..................................................... 53, 200

Quartzite Canyon ................................................ 53

Quasiarckaediscus sp. ........................................ 144

Queantoweap Sandstone ................................. 31, 35

Queantoweap Valley ............................................ 35

Quemado-Cuchillo basin ....................................... 56

R

Rain pits ..... 165, 171, 179, 203, 241, 247, 275, 277, 357

Esplanade Sandstone .................................... 277

Manakacha Formation .................................. 277

ram, Schulzospora ............................................ 143

Raticulariina eampestris .................................... 105

Red beds ........................................................ 3, 96

Red River ........................................................ 256

Red Wall Limestone ............................................. 3

Redwall Limestone ............................... 4, 23, 31, 40,

115, 341, 345, 348, 374, 379 

Bass Trail ................................................... 421

Blue Mountain Canyon ................................. 447

Blue Spring ................................................ 399

Bunker Trail ............................................... 404

Eminence Fault ........................................... 397

Grandview Trail ................................... 341,407

Havasu Canyon ........................................... 431

Hermit Trail ............................................... 418

Hidden Canyon ........................................... 483

Hindu Canyon ............................................. 496

Iceberg Canyon ........................................... 492

Kaibab Trail, north ...................................... 414

Kaibab Trail, south ............................... 341, 411

National Canyon .......................................... 436

Pigeon Wash ............................................... 479

SB Canyon ................................................ 441

Separation Canyon ....................................... 496

Snap Canyon ............................................... 475

Thunder River Trail ..................................... 426

Toroweap Valley ......................................... 452

Tuckup Canyon ........................................... 444

Twentynine Mile Canyon .............................. 395

Twin Springs Canyon ................................... 468

valleys ................................................ 145, 157

Whitmore Wash .......................................... 457

Redwall sea ....................................................... 23

Reptiles, Wescogame Formation ........................... 25

Residues, insoluble ............................................ 265

Reticulariina gonionota ...................................... 117

Recticulatisporites sp. ........................................ 143

Retispira sp. ..................................................... 121

Rhipidomella nevadensis ..................................... 70

Rhone River ..................................................... 256

Ripple lamination .................................. 213, 256, 275

Ripple marks ................... 179, 211, 220, 257, 275, 357

Esplanade Sandstone ............................. 236, 241

Hermit Shale .............................................. 275

Manakacha Formation ..................... 220, 260, 275

Watahomigi Formation ............. 211, 256, 260, 275

Wescogame Formation .................... 224, 236, 275

Rivularites permiensis ....................................... 100

sp. ................................... 97, 171, 179, 203, 277,

357, 412, 429, 439, 449, 480 

Roaring Springs Canyon ....................... ............. 412

robusta, Derbyia ............................................... 117

Rocks, classification ........................................... 336

Rod Club Member, Springer Formation ................ 144

Rostroconchs, Watahomigi Formation ............ 116, 120

rugo&a, Eosigmoilina ......................................... 144

S B Canyon, bivalves ......................................... 259

channels ........................................ 193, 195, 213

conglomerate ................. 27, 42, 163, 189, 193, 201

cross-stratification ........................... 216, 223, 234

erosion surface .............................. 160, 163, 171
INDEX 503

S B Canyon—Continued

flora ........................................................... 98

fusulinids ............................................. 183, 259

Hermit Shale .............................................. 438

Redwall Limestone ...................................... 441

ripple marks ........................................ 237, 275

stratigraphie sections ................................... 438

vertebrate animals .................................. 91, 259

San Juan Basin .......... 5, 24, 25, 57, 215, 221, 256, 258

San Juan River ................................................. 377

Sandia sp. ........................................................ 144

Sando, W. J., quoted ......................................... 143

Sandstone, Manakacha Formation ........................ 218

Watahomigi Formation ................................. 211

Weseogame Formation ................................. 221

Sandstone bodies, geometry ................................ 207

Sangre de Cristo Mountains, New Mexico ............. 115

Santa Maria Spring ............................................. 91

Schizodus ampins ............................. 120, 125; pi. F4

sp. ................................................... 81, 82, 144

sp. A ............................................... 120; pi. F4

sp. B ............................................... 120; pi. F4

Schizophoria altirostris ................ 80, 116, 122; pi. Fl

sp. .............................................................. 70

Schubertella sp. ....................................... 70,89, 111

Schulzospora rara ............................................. 143

Schwagerina linearis .......................................... Ill

sp. .............................................. 70, 71, 89, 111

Scoyenia gracilis ........................................ 100,180

sp. ............................................................. 183

Sea urchins, Weseogame Formation ...................... 103

Seed ferns ......................................... .............. 202

Selenimyalina sp. .............................................. 120

Seligman .......................................................... 492

Hermit Shale .............................................. 492

stratigraphie sections ................................... 492

Separation Canyon ........................................ 40, 492

accretal limestone ................................. 345, 346

eephalopods ................................................ 121

conglomerate ............................................... 193

conodonts .......................................... 77, 83, 84

corrensite .............................................. 24, 315

faunas ........................................................ 123

fauna ......................................................... 144

fish ............................................................ 121

gastropods .................................................. 121

grain size ................................................... 229

jasper ........................................................ 200

pelecypods ........................................... 120, 121

petrography ................................................ 355

Redwall Limestone ...................................... 496

ripple marks ............................................... 275

stratigraphie sections ................................... 492

sharks teeth ................................................. 83

Separation valley ............................................... 139

Septimyalina sp. ................................................ 82

sp. A ............................................... 120; pi. F4

sp. B ............................................... 120; pi. F4

setiger, Torynifer ............................................... 115

Sevier uplift ....................................................... 55

Shale, defined .................................................... 10

Shansiella sp. ................................................... 121

Shark fossils ..................................................... 181

Watahomigi Formation .................................. 83

Sharks teeth, Pakoon Limestone ..................... 89, 183

Weseogame Formation ............................ 85, 259

Shinumo Trail ................................................... 422

erosion surface ............................................ 171

Hermit Trail ............................................... 422

stratigraphie sections ................................... 422

Shivwitz Plateau ........................................... 44, 458

gypsum ....................................................... 46

Shrinkage cracks ....... 179, 182, 203, 241, 275, 276, 357

Silica rock ........................................................ S67

Silicon ................................................. 293, 297, 301

16.5 Mile Canyon, bioelasts ................................. 259

Skeletal remains .............................. 96, 346, 347, 351

Skewness, sand ................................................. 209

Smectite .......................... 289, 297, 301, 308, 309, 329

Snap Canyon ...................................... 33, 46, 48, 471

Snap Canyon—Continued

accretal limestone ........................................ 346

brachiopods ................................................. 116

conglomerate .............................. 44, 47, 190, 201

cross-stratification ........................................ 258

dolostone .................................................... 348

erosion surface ..................................... 160, 171

fauna .................................................. Ill, 123

Hermit Shale .............................................. 471

insoluble residue .......................................... 272

marine faunas ........................................ 88, 259

Pakoon Limestone ....................................... 472

peleeypods .................................................. 120

Redwall Limestone ...................................... 475

shrinkage cracks ................................... 182, 276

silica rock ................................................... 367

stratigraphie sections ................................... 471

warping ...................................................... 145

Snap Creek, erosion channels ............................... 42

Snap Point, shrinkage cracks ............................... 276

Sodium ...................................................... 309, 312

solidus, Punctatisporites ............................. 143, 144

soli&ortus, Auroraspora ............................... 143, 144

Sonora basin ..................................................... 352

Sonoran geosyncline ...... 25, 56, 66, 67, 68, 69, 103, 221

Sonoran seas ................................................. 58, 67

Sonoran trough .................................................. 56

Spandelinoides sp. ........................................ 89, 111

Spencer Canyon ................................................ 492

Sphenopsids, buried-valley deposit ....................... 141

Sphenophyllum sp. ............................................ 202

Sphenotus .......................................................... 82

Spirifer ........................... 435, 444, 453, 479, 480, 496

Spiriferina ........................................................ 444

Springer Formation, Oklahoma ............................ 144

Staffella ............................................................ 85

Stenichnus yakiensis ........................................... 92

stereon, Hadrohercos ................................... 143, 144

Straparollus (Euomphalus) sp. ............................ 121

Stratification, contorted ...................................... 277

fluvial ........................................................ 247

marine ....................................................... 247

Stratigraphy .............................................. 105, 397

Strophomina .............................................. 479, 480

Strophostylus sp. ............................................... 121

sturdevanti, Anomalopus ..................................... 92

subtilita, Composite, ................................. 117; pi. F3

supaiensis, Tridentichnus .................................... 92

Surprise Canyon, buried-valley deposits ................ 139

fauna ......................................................... 144

Sycamore Creek, correlation with Supai Group ....... 69

Sylvite ............................................................. 378

Syringopora multattenuata ............................ 85, 111

sp. ........................................................ 82, 478

Tanner Trail. See Bunker Trail.

tanoensis, Anthracospirifer .... 80, 117, 121, 122; pi. F3

Taosia sp. ........................................................ 121

teres, Endothyra ................................................ 85

terminalis, Wilkhigia ............................... 120; pi. F4

Tetrapod tracks .................................................. 92

Thunder River Trail ........................................... 123

bioelasts .....'................................................ 259

bryozoans ................................................... 259

channels ..................................................... 193

conglomerate ............................. 41, 191, 193, 202

contorted stratification ................................. 280

cross-stratification ................................. 216, 234

erosion surface ..................................... 160, 171

flora ........................................................... 98

foraminifers ................................................ 102

Hermit Trail ............................................... 423

rain pits ..................................................... 277

Redwall Limestone ...................................... 426

ripple marks ........................................ 236,275

stratigraphie sections ................................... 423

Titanium .......................................................... 297

Toeniopteris ....................................................... 97

Tonto Creek, fossils ............................................ 69

Topocoba Trail .................................................. 426

channel-fill .................................................. 164

channels ..................................................... 195

conglomerate ........................................ 195, 200

cross-stratification ................................. 223, 235

erosion surface ............................................ 171

flora ........................................................... 98

fossils ........................................................ 203

Hermit Shale .............................................. 426

ripple marks ............................................... 275

shrinkage cracks .......................................... 276

stratigraphie sections ................................... 426

Toroweap Formation ............................................. 3

Toroweap Point, corrensite .................................. 24

cross-stratification ........................................ 256

evaporite deposits ........................................ 377

Toroweap Valley ........................................ US, 452

brachiopods ............................... 80, 116, 191, 258

bryozoans .................................................... 82

conglomerate ............ 41, 42, 46, 163, 191, 193, 201

contorted structures ..................................... 237

corals .......................................................... 82

corrensite ................................................... 315

cross-stratification ................................. 235, 258

erosion surface ........................ 157, 163, 169, 171

evaporite deposits ........................................ 377

fauna ............................................. 77, 121, 122

fish............................................................ 121

fossils .................................................... 3, 115

grain size ................................................... 229

gypsum ............................................ 46, 48, 377

Hermit Shale .............................................. 449

illite ........................................................... 327

jasper ........................................................ 374

petrography ......................................... 348, 357

Redwall Limestone ...................................... 452

shark spine .................................................. 83

stratigraphie sections ............................ 449, 452

Torynifer setiger ...................................... 115; pi. Gl

sp. 144

Trace Creek Shale Member, Bloyd Shale .............. 123

Tracks, amphibian ...................................... 203, 247

Transgressions, sea ............................................ 179

transversus, Punctospirifer ........................... 80, 105,

117, 121, 122; pi. F3 

Trilobites, abundance .......................................... 77

buried-valley deposits ................................... 144

Manakacha Formation ................................... 85

Watahomigi Formation ........................... 82, 115,

116, 121, 182, 258, 346 

Tridentichnus supaiensis ..................................... 92

Triquitrites sp. .................................................. 143

triradiatus, Knoxisporites ............................ 143, 144

Triticites plicatulus ............................................ 72

sp. .................................. 62, 70, 85, 89, 109, 111

Tuckup Canyon ................................................. 442

brachiopods .......................................... 258, 363

calcitic dolomite ........................................... 345

channels .............................................. 193, 195

channel fill .................................................. 164

conglomerate .......................................... 47, 193

corrensite ................................................... 315

cross-stratification ................................. 223, 235

erosion surface ..................................... 160, 171

Hermit Shale .............................................. 442

petrography ......................................... 348, 357

Redwall Limestone ...................................... 444

stratigraphie sections ................................... 442

worm trails ................................................. 183

turbatans, Ammobatrachus .................................. 92

Twentynine Mile Canyon .................................... 391

clay mineralogy ........................................... 315

cross-stratification ........................... 224, 234, 258

erosion surface ............................................ 171

flora .......................................................... 203

Hermit Shale .............................................. 391

petrography ......................................... 355, 357
504 THE SUPAI GROUP OF GRAND CANYON

Twentynine Mile Canyon—Continued

Redwall Limestone ...................................... 395

stratigraphic sections ................................... S91

Twin Springs Canyon .................... 44, 46, 48, 49, 1,61,

channel-fill ........................................... 164, 195

conglomerate ........................................ 189, 195

cross-stratification ........................... 223, 258, 346

endothyra ................................................... 259

erosion surface ................................ 42, 165, 171

fusulinids ............................................. 183, 259

Hermit Shale .............................................. 464

mineralogy .................................................. 348

petrography ................................................ 347

rain pits ..................................................... 277

Redwall Limestone ...................................... 468

stratigraphic sections ................................... 1,61,

trilobites .................................................... 346

217 Mile Canyon, buried valleys ........................... 145

Tyler Formation, Montana .................................. 122

U

Uncompahgre uplift ............................................ 56

Ural Mountains ................................................. 125

Utah uplift ........................................................ 55

validus, Punctatisporites .................................... 143

Valley-fill deposits ............................................. 139

varicostatum, Diabolocera Zone ........................... 123

Vertebrate animals, Esplanade Sandstone .............. 93

Watahomigi Formation ................................. 346

Wescogame Formation ....................... 25, 91, 259

Virgilian Provincial Series ................................... 194

Virgin Mountains, fusulinids ........................... 72, 108

Volvotextularia sp. ............................................ 144

W

Walchia sp. ............................ 97, 163, 171, 179, 202,

203, 241, 357, 412, 421, 459 

Wapanucka Limestone, Oklahoma ........................ 123

Warping, pre-Supai ............................................ 145

Watahomigi embayment ....................................... 64

Watahomigi Formation ................................... 35, 39

accretal limestone ........................................ 31,5

age ..................................................... 105, 115

bioclastic debris ......................... 23, 100, 259, 346

biostratigraphy ............................................ 115

bivalves ................................................. 23, 259

brachiopods ........ 23, 65, 69, 77, 84, 100, 105, 115,

116, 122, 182, 189, 258, 346, 363; pis. Fl, F2, F3 

bryozoans .. 23, 82, 100, 115, 116, 122, 258, 346, 347 

carbonate rocks ........................................... 379

cephalopods ......................................... lie, 121

chert...................................... 190, 213, 344, 367

chlorite ................................................. 23, 315

clay mineralogy .................................... 3H, 328

climate ....................................................... 125

conglomerates ............................................. 189

conulariids ........................................ 77, 82, 116

corals ........................... 70, 82, 115, 116, 125, 258

correlations ................................................. 122

Page 

Watahomigi Formation—Continued

corrensite .......................... 23, 311, 315, 328, 363

crinoids .......................................... 82, 100, 122

cross-bedding ............................................... 23

cross-stratification ........................... 211, 249, 260

dolostone .................................................... 31,8

echinoderms .................................... 82, 116, 121

environment of deposition ............................. 260

erosion surfaces .................................... 157, 182

facies ......................................................... 31,0

fauna ............................................. 77, 115, 258

fenestrae .................................................... 345

fish fossils ........................................... 116, 121

flora ........................................................... 97

foraminifers ............ 23, 70, 83, 84, 100, 144, 182,

259, 335, 344, 346, 347 

fossils ...................... 3, 23, 46, 115, 182, 258, 346

fusulinids ................................... 23, 69, 105, 259

gastropods ... 80, 84, 115, 116, 120, 258, 346; pi. F4 

grain sizes .............................. 211, 31,1,, 31,5, 31,7

grain types .................................... SU, 31,5, 31,7

history ........................................................ 23

insoluble residues ........................................ 265

isotopic data ............................................... 363

jasper ................... 40, 46, 213, 344, 346, 367, 374

kaolinite ......................................... 23,315,363

lithology ........................................... 23, 1,6, 157

marine fauna ............................. 77, 189, 258, 260

mineralogy .................................................. 31,1,

mixed-grain limestone .................................. 31,7

ostracodes .................................................. 346

paleography ........................................... 57, 125

pelecypods ................................ 81, 84, 100, 115,

116, 120, 182, 258; pi. F4 

petrography ................................................ SU

ripples ................................... 211, 256, 260, 275

rostroconchs ......................................... 116, 120

sandstone ................................................... 211

silica rock ................................................... 367

trilobites .............. 82, 115, 116, 121, 182, 258, 346

Watahomigi Point ............................................... 35

Weaver, C. E., quoted ....................................... 374

Wedekindellina sp. ....................................... 70, 108

Wentworth scale ........................................... 10, 207

Wescogame Formation .............................. 24, 35, 40

age ............................................................ 109

amphibians .................................................. 25

bioclastic debris .................................... 103, 355

bivalves .......................................... 25, 103,259

brachiopods ................................................. 103

bryozoans ............................................ 103, 259

carbonate rocks .................................... 379, 384

chert.......................................................... 193

chlorite ................................................. 25, 325

clay mineralogy .................................... 324, 329

cliff unit ...................................................... 41

conglomerate ............................................... 193

contorted stratification ................................. 280

coral .............................................. 85, 111, 259

corrensite ................................................... 325

crinoids ...................................................... 103

cross-stratification ...................... 25, 222, 249, 261

cyclothem ................................................... 186

deposition .................................................... 24

environment of disposition ............................ 261

erosion surface ..................................... 160, 182

Page 

Wescogame Formation—Continued

fauna ........................................ 25,55, 182,259

flora ........................................................... 98

foraminifers ................................... 103, 182, 259

fossils ................................................... 25, 259

fusulinids ....................... 25, 67, 85, 111, 182, 259

gastropods .............................................. 25, 85

grain-size distribution ............................ 222, 261

ichnite fauna ................................................ 92

insoluble residues ........................................ 272

isotopic data ............................................... 363

jasper ................................................. 193, 374

kaolinite ................................... 25, 314, 325, 364

lithology ...................................................... 47

marine fauna ................................... 85, 259, 261

mollusks ..................................................... 259

petrography ................................................ 352

reptiles ....................................................... 25

ripple marks .................................. 224, 236, 275

sandstone ................................................... 221

sea urchins ................................................. 103

vertebrates ....................................... 25, 91, 259

Wescogame Point ............................................... 35

West Canyon Limestone, Utah ............................ 123

Whitmore Wash ...................................... 35, 49, 203

aceretal limestone ........................................ 345

aphanitic limestone ...................................... 341

conglomerate ............................. 44, 163, 189, 201

contorted bedding ........................................ 221

contorted stratification ................................. 280

cross-stratification ................................. 256, 258

endothyra ................................................... 259

erosion surface ............................... 157, 163, 171

evaporite deposits ........................................ 377

fauna .......................................................... 77

foraminifers ......................................... 183, 344

fossils ........................................................ 203

fusulinids ............................................. 183, 259

grain size ................................................... 229

Hermit Shale .............................................. 457

mineralogy .................................................. 348

pelmatozoans ............................................... 344

petrography ................................... 347, 348, 357

Redwall Limestone ...................................... 457

stratigraphic sections ............................ 453, 457

See also Queantoweap Valley. 

Wilkingia terminalis ................................ 120; pi. F4

Winslowoceras henbesti Ammonoid Zone ............... 123

Worm trails .................................. 179, 203, 241, 277

Esplanade Sandstone .................................... 183

Pakoon Limestone ....................................... 183

Worihenia sp. ................................................... 121

Yaki Trail, flora ................................................. 97

yakiensis, Stenichnus .......................................... 92

Yeso evaporite basin .......................................... 377

Yoldia Sea, Finland ........................................... 256

Zellerina sp. ..................................................... 144

Zuni positive element .......................................... 68

Zuni uplift ......................................................... 53

U.S. GOVERNMENT PRINTING OFFICE : 1983 O - 417-793