Devonian Rocks and 

Paleogeography of 

Central Arizona 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 

Devonian Rocks and 

Paleogeography of 

Central Arizona 

By CURT TEICHERT 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 

Stratigraphic, lithologic, and paleoecologic studies 

of the Devonian rocks of central Arizona, as a 

basis of reconstructing Devonian paleogeography 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary 

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director 

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

Washington, D.C. 20402 
CONTENTS 

Page 

Abstract_____________________________________________ 1 

Introduction _______________________________ - ___ -______ 3 

Location and geography___________________________ 3 

Previous work____________________________________ 6 

Scope of present investigations and methods of study__ 9 

Color of rocks ________ -- _______ - ______ -- ___ - ___ -__ 11 

Historical summary and evaluations of stratigraphic 

nomenclature___________________________________ 12 

Northern Arizona_____________________________ 12 

Southern Arizona_____________________________ 12 

Central Arizona _______ - ___ - _______ -__________ 13 

Sycamore Creek Sandstone of Lausen and 

Wilson (1925) _______________________ -- _ 14 

Jerome Formation and Island Mesa Beds____ 15 

Lower Ouray Formation of Stoyanow (1936) _ 15 

Eastern Arizona _________ -_- _______________ -__ 16 

Acknowledgments _________ - ___ - _______________ -_- 16 

Outline of the Devonian System in central Arizona and 

proposed stratigraphic nomenclature__________________ 16 

Rocks of the Martin Formation _____________________ -__ 18 

Terminology and classification of carbonate rocks_-_- 18 

Classifications based on chemical composition____ 19 

Classifications based on structural and textural 

features___________________________________ 21 

Classifications based on origin and environment__ 21 

Beckers Butte Member _________________________ -_- 21 

Comparison with sandstones of the Jerome Member_______________________________________ 25 

Comparison with the Tapeats Sandstone of the 

Jerome area________________________________ 25 

Mode of deposition, age, and paleogeography____ 27 

Jerome Member__________________________________ 29 

Fetid dolomite unit___________________________ 29 

Aphanitic dolomite unit_______________________ 33 

Type section_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 33 

General lithology outside the Jerome area____ 33 

Distribution______________________________ 37 

Occurrence of limestone____________________ 37 

Occurrence of silica_______________________ 37 

Detrital quartz_______________________ 38 

Chert nodules________________________ 38 

Authigenic silica______________________ 38 

Occurrence of clastic rocks_________________ 39 

Fossils___________________________________ 40 

Mode of deposition and diagenetic history_ _ _ 40 

Upper unit___________________________________ 41 

Type section__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 42 

Facies west and north of Jerome____________ 43 

The area southeast of Jerome______________ 44 

Upper East Verde River and Pine Creek areas_ 45 

Rocks of the Martin Formation-Continued Page 

Jerome Member-Continued 

Upper unit-Continued 

The northeastern onlap belt ____ --------·---- 4 7 

The area from middle Canyon Creek to the 

upper Salt River_________________________ 51 

The Roosevelt-Globe area___________________ 54 

Fossil faunas and paleoecology ____ ----.. ---- 55 

Note on terminology _____ --_-----.. ---- 55 

Distribution and occurrence of fossil 

groups ______________ ----_ .. ---- 56 

Protozoa ____________ -------.. ---- 51 

Stromatoporoidea _________ ---·---_- 57 

Anthozoa ___________ --------·----- 57 

Bryozoa ______________ ------ .. - - - - 58 

Brachiopoda_____________________ 58 

Mollusca________________________ 62 

Ostracoda_______________________ 63 

Echinodermata _______ -- __ - __ ----- 63 

Conodonts _______________ - __ --- _- 63 

Fishes___________________________ 64 

Calcispheres ____________________ - 65 

Mixed assemblages ________ - ___ -___ 65 

Trails and burrows _______________ - 66 

Some gross lithological features of the Jerome 

Member___________________________________ 67 

Relationships between dolomitization, insoluble residue, and total carbo11ate content_- 67 

Insoluble-residue cycles in carbonate se- quences _______________________________ 71 

Luster mottling ___________________ - __ -- __ - 72 

Siliceous detrital rocks_____________________ 73 

Texture of aphanitic carbon ate rocks ______ -- 74 

Introduction .. _____________ ----------- 74 

Electron-microscope investigations______ 76 

Depositional environment and diagenetic history of the carbonate facies of the .Jerome 

Member_______________________________ 78 

Role of diagenesis _______________________ - - 78 

Fetid and aphanitic dolomite units __ J_______ 81 

Upper unit_______________________________ 84 

Sedimen tational history_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 84 

Dolomitization ______________________ - 85 

Silica________________________________ 85 

Discussion of isopach maps and notes on wells _______ - 87 

Age and correlation of the Martin Formation_________ 89 

Beckers Butte Member-- ____________ --:- _______ - 89 

Jerome Member______________________________ 89 

Comparison with other Devonian strata in the 

Rocky Mountain province __________________ - 91 

m 
IV CONTENTS 

Rocks of the Martin Formation-Continued Page Rocks of the Martin Formation-Continued Page 

Summary of facies pattern and paleogeography__ _ _ _ _ _ 92 Microfossils of the Jerome Member-Continued 

Comments on sections_________________________ 92 

Section A-A'----------------------------- 92 

Section B-B' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 93 

Section C-C' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 93 

Section D-D' ----------------------------- 93 

Section E-E' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 94 

Section F-F'----------------------------- 94 Section G-G' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 94 

Section H-H' ---------------------------- 95 

Section I-I' ----------------------------- 95 

Paleogeography_______________________________ 96 

Calcispheres _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 99 

Thin-walled calcispheres_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 100 

Thick-walled calcispheres _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 100 

Affinities _________________________________ 102 

Umbella Maslov (in Bykova and Polenova, 

1955; non d'Orbigny, 1841) _________ 103 

Distribution __________________________ 104 

Nomenclature ________________________ 104 

Affinities _____________________________ 104 

Stratigraphic sections of the Martin Formation___________ 105 

Explanation ______________________________________ 105 

Microfossils of the Jerome Member__________________ 97 References cited ______________________________________ 169 

PLATES 

FIGURE 

Tintinnina(?) ------- _ _ _ __ _ _ __ __ _ __ _ __ __ _ _ _ _ ___ 97 IndeX----------------------------------------------- 177 

1-13. 

14. 

15. 

16. 

17. 

18-19. 

20. 

21. 

22-23. 

24. 

25-26. 

27. 

28-31. 

32. 

1. 

2. 

3. 

4-5. 

6. 

7-9. 

10. 

ILLUSTRATIONS 

[Plates 1-21 follow index; plates 22-32 are in pocket] 

Rocks of the: 

1. Beckers Butte Member and the fetid dolomite unit of the Jerome Member. 

2-3. Fetid dolomite unit of the Jerome Member. 

4-6. Aphanitic dolomite unit of the Jerome Member. 

7. Aphanitic dolomite unit and the upper unit of the Jerome Member. 

8-9. Upper unit of the Jerome Member. 

10-11. Upper unit of the Jerome Member from vicinity of onlap belt. 

12-13. Upper unit of the Jerome Member. 

Luster mottled rocks and silicification. 

Silicification, calcispheres, tintinnids(?). 

Calcispheres, tintinnids(?). 

Calcispheres, ostracodes. 

Calcispheres. 

Calcispheres, U mbella. 

Umbella. 

Diagrams showing: 

22. Total carbonate content and MgO percentage of total carbonate or rocks of the Jerome Member. 

23. Total carbonate content and MgO percentage of total carbonate and insoluble residue histograms of 

bonate rocks of the Jerome Member. 

Histograms showing grain-size distribution of sandstones of the Martin Formation. 

Stereopairs of electron micrographs of aphanitic limestone and aphanitic dolomite. 

Distribution map of the Beckers Butte Member and isopach maps of the Jerome Member. 

Sections: 

28. A-A' and B-B', Beckers Butte and Jerome Members. 

29. C-C', D-D', E-E', and F-F', Jerome Member. 

30. G-G' and H-H', Beckers Butte and Jerome Members. 

31. I-I', Beckers Butte and Jerome Members. 

Index maps showing locations of measured stratigraphic sections. 

carPage 

Index map of Arizona showing location of the area covered by this report________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 4 

Photograph of the north side of the Salt River gorge__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 5 

Diagram showing the MgO content of rocks of the Martin Limestone and of the Jerome Member___________ 17 

Photographs showing the: 

4. Beckers Butte Member in the Salt River gorge on U.S. Highway 60______________________________ 22 

5. Contact of the Beckers Butte Member and the Jerome Member on U.S. Highway 60______________ 23 

Histograms showing grain-size distribution of rocks of the Tapeats Sandstone and Beckers Butte Member__ 24 

Photographs showing the: 

7. Beckers Butte Member resting on granite at the East Verde River_______________________________ 24 

8. Stratigraphic section on the south side of Theodore Roosevelt Lake_______________________________ 25 

9. Crossbedded Tapeats Sandstone underlying a typical section of the Jerome Member northeast of 

Jerome---------------------------------------------------------------------------------- 26 

Diagram showing the distribution of important heavy minerals in the Beckers Butte Member and the Tapeats 

Sandstone------------------------------------------------------------------------------------- 28 
CONTENTS v 

Page 

FIGURE 11-17. Photographs showing: 

11. Very fine grained laminated dolomite from the upper part of the fetid dolomite unit_______________ 30 

12. The basal part of the fetid dolomite unit of the Jerome Member_ _______ --_-_---- __ -____________ 31 

13. Aphanitic dolomite having a conchoidal fracture and containing much detrital quartz______________ 34 

14. A fresh outcrop of the aphanitic dolomite unit on U.S. Highway 60______________________________ 34 

15. Mud cracks in aphanitic dolomite on the East Verde River_____________________________________ 35 

16. Lamination and shrinkage cracks in aphanitic dolomite on the East Verde River__________________ 35 

17. Aphanitic dolomite having an intrastratal erosion surface_______________________________________ 36 

18. Geologic sketch map and section of area southeast of Pine----------------------------------------·----- 46 

19. Photograph showing fine-grained slightly calcitic dolomite containing Amphipora skeletons ___________ -·_____ 52 

20. Diagram showing typical facies sequence of the upper unit of the Jerome Member in the middle Canyon Creek 

area--------------------------------------------------------------------------------------·----- 53 

21-31. Photographs showing: 

21. The top of the Jerome Member in Flying V Canyon--------------------------------------·----- 54 

22. The underside of a siltstone bed having casts of large invertebrate tracks from the upper unit of the 

Jerome Member ___________________________________________________________________ -·_____ 55 

23. An intraformational solution surface in the lower part of the upper unit of the Jerome Member at 

Pinal Creek _______________________________________________________________ - _______ .. _ _ _ _ _ 56 

24. A thanatocoenosis composed of massive stromatoporoid, a Disphyllum colony, surrounded by a growth 

of Syringopora in dolomitic limestone ________________________________________________ -·_____ 59 

25. A thanatocoenosis composed of Disphyllum sp. and Aulopora sp., in dolomitic limestone____________ 60 

26. Thamnopora colonies in calcitic dolomite_____________________________________________________ 61 

27. A coquina composed of silicified shells of Theodossia cf. T. hungerfordi (Hall) and Cyrtospirifer sp_ _ _ _ 62 

28. A coquina composed entirely of silicified shells of Schizophoria iowensis (Hall)_____________________ 63 

29. Top of bedding plane of a limestone containing a silicified taphocoenotic assemblage _________ -·_____ 64 

30. Articulated gaping brachiopod shells indicating rapid burial and Rhizocorallium and other burrows _ _ 65 

31. A coquina composed of silicified shells of Camarotoechia sp. and Cranaena? SP----------------·----- 66 

32. Graphs showing MgO percent of total carbonate plotted against total carbonate from rocks of the Jerome 

Member--------------------------------------------------------------------------------------- 68 

33. Diagram showing distribution of heavy minerals in the sandstones of two typical sections of the Martin 

Formation_____________________________________________________________________________________ 75 

34-35. Electron micrographs of: 

34. Subaphanitic magnesian limestone___________________________________________________________ 78 

35. Aphanitic dolomite________________________________________________________________________ 79 

36. Diagram comparing current terminologies for diagenetic and related processes_______________________ _ _ _ _ _ 80 

37. Section showing stratigraphic relations at the close of deposition of the Martin Formation_________________ 98 

38-39. Sections of: 

38. Calcispheres------------------------------------------------------------------------------ 101 

39. Specimens of U mbella sp_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 103 

40. Diagram reconstructing suggested successive growth stages of U mbella___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 104 

TABLES 

Page 

TABLE 1. Comparative table of stratigraphic nomenclature applied to Devonian rocks in central Arizona___________________ 16 

2. Subdivisions of the Martin Formation in central Arizona ______________________________________________ .. _____ 19 

3. Thickness of Martin Formation and its suhdivisions__________________________________________________________ 20 

4. Thickness of insoluble residue cycles in Jerome Member (section 41)-------------------------------------·----- 71 

5. List of samples studied with the electron microscope _________________________________________________________ 77 

6. First appearance of coelenterates above the base of the upper unit of the Jerome Member __________________ -·_____ 84 

7. Measurements of calcispheres on figure 1 of plate 20--------------------------------------------~------·----- 101 

8. Measurements of cross sections of specimens of U mbella Maslov in sample T56-52l _______________________ -· _ _ _ _ _ 103 

DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

BY CuRT TEICHERT 

ABSTRACT 

The Devonian rocks described in this report lie in Gila, 

Navajo, Yavapai and Coconino Counties, Ariz. The main outcrop belt extends, in places discontinuously, for about 90 miles 

along the foot of the southwestern edge of the Colorado Plateau 

from the upper Salt River area northwestward across Salt 

River Draw and Canyon Creek to the foot of the Mogollon Rim 

as far as the vicinity of Pine. Southwest of this belt lies a disturbed area where Devonian and later Paleozoic rocks are folded 

and faulted, and their outcrops, therefore, are discontinuous. 

Important sections studied in the disturbed belt are in the Globe 

area, south of Theodore Roosevelt Lake at Limestone Hills, in 

Chasm Creek, and in the Jerome area. A partial section at 

Elden Mountain in the San Francisco volcanic field in Ooconino 

County was studied. 

Over most of the area the Devonian rocks rest unconformably 

on Precambrian rocks and have a relief of several hundred feet. 

The surface on Precambrian rocks was almost leveled and 

covered with sediments during Devonian time. 

The oldest Devonian rocks in central Arizona are channelfilling sandstones, which are here named the Beckers Butte 

Member of the Martin Formation. This member is Early or 

Middle Devonian in age. It is overlain by the Jerome Member 

of the Martin, which consists mostly of carbonate rocks and 

locally, of admixtures of sandstone, siltstone, and shale. The 

upper unit of the Jerome is early Late Devonian in age. The 

Beckers Butte and Jerome Members are herein combined in the 

Martin Formation, which is at least in part equivalent to the 

Late Devonian Martin Limestone of the Bisbee area in southeastern Arizona. 

The Beckers Butte Member is a channel fill that ranges in 

thickness from a few feet to 200 feet. Typically, it consists of 

medium- to coarse-grained crossbedded poorly sorted sandstones. 

Partial fillings of three major channels are known: in Canyon 

Creek and extending south of the Salt River, on Aztec Peak, and 

at Roosevelt Dam. In places, shale and impure dolo~ite, as 

much as 20 feet thick, occur at the top of the Beckers Butte 

Member, which has yielded a fairly rich psilophyte flora of 

Early or Middle Devonian age in one locality on the Salt River. 

Discontinuous distribution of this shaly unit probably indicates 

a clay-pan topography during the closing stages of deposition of 

the Beckers Butte Member and shortly before the onset of 

marine conditions. 

The Jerome Member rests conformably on the Beckers Butte 

Member. It has been subdivided into three units, which in 

ascending order are the fetid dolomite unit, the aphanitic dolomite unit, and the upper unit. The fetid dolomite unit is as 

much as 55 feet thick and consists of fine- to medium-grained 

dolomite, which is finely interlaminated with organic matter 

derived from planktonic organisms. In one undolomitized lo· 

cality the original rock can be seen to have been aphanitic 

laminated limestone. 

The aphanitic dolomite unit consists almost entirely of 

aphanitic and subaphanitic dolomite and, locally, of intercalations of aphanitic limestone and fine-grained sandstone. It is 

as much as 159 feet thick but is typically between 100 and 150 

feet thick. The unit is largely unfossiliferous, although brachiopods, ostracodes, and calcispheres are found locally. Many 

beds contain detrital quartz grains and secondary chert. 

Both the fetid and the aphanitic dolomite units have typical 

lithology and occur in all Devonian sections along a broad belt 

extending from the Jerome area in the northwest to the upper 

Salt River area in the southeast and also at Limestone Hills, 

Theodore Roosevelt Lake, and the Globe and Superior areas. 

Indications are, therefore, that these rocks once extended over an 

area of about 14,000 square miles. Toward the northeast both 

units wedge out along a line running several miles southwest 

of the Mogollon Rim and continuing southeastward into the 

upper Canyon Oreek area. 

The upper unit of the Jerome Member is as much as 385 feet 

thick and has a more varied lithology than the other units. In 

the Jerome area it consists entirely of dolomite rock, mostly 

fine- to medium-grained and commonly saccharoidal, and contains subordinate beds of aphanitic dolomite. This pure carbonate facies extends southeastward as far as the East Verde 

River. At Theodore Roosevelt Lake a considerable sandy component in the upper unit occurs, and the amount of sand increases southeastward in the direction of Globe. This terrigenous material probably came from an unknown source in 

the southeast. 

Toward the northeast the upper unit is transgressive over a 

considerable area of the Defiance uplift, beyond the area of 

distribution of the fetid and aphanitic dolomite units. Along 

and close to the onlap belt, the upper unit commonly contains 

appreciable amounts of sandstone and shale, which tend to 

decrease in a southwesterly direction away from the onlap 

belt. At the end of the deposition of the upper unit, two islands 

of unknown but probably small extent-Pine Island and Christopher Island-remained above sea level near the southeastern 

edge of the onlap belt. 

In the entire area of investigation, the carbonate rocks of 

the upper unit resemble those of the type section at Jerome, 

where this unit consists entirely of carbonate rocks. They are 

very fine grained to medium-grained dolomites and contain 

intercalated aphanitic dolomites and limestones. Mottling is a 

characteristic feature of many of the nonaphanitic rocks. 

In general, the fossil content of the rocks of the upper unit 

increases from bottom to top, and the uppermost 100-150 feet is 

in most places characterized by richly fossiliferous horizons 

containing varied stromatoporoid, coral, and brachiopod faunas. 

Among genera represented are: Actinostroma, Gerronostroma, 

Stictostroma, Amphipora, Breviphyllum, Tabulophyllum, Disphyllum, H emagonaria, Pachyphyllum, Tabellaephyllum, Alveolites, Aulopora, Striatopora, Syringopora, Thamnopora, 

1 
2 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

Sckizophoria, Nervostrophia, Devonoproductus, Stenocisma, 

Oamarotoechia, Atrypa, Spinatrypa, Platyra.okella, Oyrtospirijer, 

Tenticospirifer, Tkeodossia, and Brackytkyrina. These fossils 

QCcur locally in great abundance as thanatocoenoses (death assemblages of fossils preserved in life position) or as taphocoenoses (burial assemblages), which include many brachiopod 

coquinas. These and other observations indicate gradual deep--

ening of the sea during deposition of the upper unit of the 

Jerome Member. 

Other fossil groups such as Protozoa, Mollusca, Ostracoda, 

Echinodermata, and fishes are present but subordinate. Conodonts were extracted from only one sample, which yielded, 

among other forms, Polygnathus normalis Miller and Youngquist and Palmatolepis triangularis Sannemann. Most limestones contain caleispheres of considerable morphological variety and locally of rock-building importance. 

Several gross lithological features of the Jerome Member, 

especially its carbonate rocks, were investigated in detail. No 

straight-line relationships exist between insoluble residue content and degree of dolomitization. Limestones tend to be pure, 

whereas dolomites contain highly variable amounts of insoluble residues. In aphanitic dolomites a positive correlation between total carbonate and MgO content tends to occur. 

The insoluble residues of carbonate rocks of the Jerome Member are vertically graded. Rock cycles that begin with medium- to coarse-grained insolubles and in which the insolubles 

become finer towards the top where silt and clay or clay only 

are present can be recognized. In the Jerome type section, 10 

such cycles are present. These may reflect cyclical climatic 

changes. 

The sandstones of the Jerome Member are generally fine 

grained and well sorted and thus contrast with most rocks of 

the Beckers Butte Member, which are medium to coarse grained 

and poorly sorted. 

Electron-microscope study of the texture of aphanitic carbonate rocks disclosed significant differences between aphanitic 

limestone and aphanitic dolomite. The limestone consists of 

densely packed irregularly polyhedral crystals mostly 1-3 microns in diameter; the dolomite consists of a more ma8sive 

aggregate of crystalline dolomite in which rhombohedral cleavage is prevalent and that contains many individual rhombohedral crystals of greatly varying s1izes, as small as 1 micron 

or less. 

The rocks of the Jerome Member of central Arizona were 

deposited on a gradually subsiding platform in the area southwest of the Defiance uplift. The fetid dolomite unit, the lowest 

of the three units in the member, formed as a lime mud interlaminated with much organic material, possibly in a large embayment. The rocks of the aphanitic dolomite 1mit formed as 

lime mud in very shallow open water, possibly in an almost 

tideless sea on a wide shelf that was intermittently and locally 

exposed to the air when strong offshore winds lowered sea level. 

Gradual deepening of the sedimentation area took place during 

deposition of the upper unit. Sedimentation of calcareous deposits continued in offshore areas 8Uch as near Jerome. In 

east-central Arizona a supply of terrigenous material was furnished partly from the Defiance uplift and partly from an unidentified source southeast of the area covered by the present 

investigations. The upper part of the upper unit was laid 

down in water below the zone of wave turbulence. 

Most rocks of the Jerome Member have had a complex diagenetic history under conditions of very low pressures and 

tempeJ:'Iatures. No rocks of the Martin Formation in central 

Arizona have ever been covered by more than 3,000-3,500 feet 

of post-Devonian sediments. Aphanitic dolomites are probably 

not of primary sedimentary origin. They are more probably 

the result of penecontemporaneous or eodiagenetic dolomitization of lime mud before lithification. Volume shrinkage during 

this process contributed to compaction of the sediment; hence, 

aphanitic dolomites are nonporous. Fossils may be preserved 

as "ghosts" in these rocks. 

Granular dolomits were formed from limestones through formation of authigenic dolomite crystals, which grew in-number 

until they completely replaced the parent rock. In such rocks 

all fossil structures were completely destroyed unless they became silicified. 

Nondolomitized aphanitic limestone tended to become recrystallized through grain growth. In extreme stages of this 

evolution, the rock consists of finely crystalline ( "s'Parry") 

calcite in which are embedded small lumps or "pellets" of 

aphanitic limestone. Fossils are often recognizable as "ghosts" 

in the crystalline calcite. Recrystallization through grain 

growth also takes place in aphanitic dolomite in a manner 

similar to that in limestone, though more rarely. The dolomite 

in aphanitic dolomite rock also can be reconstituted into dolomite rhombohedra similar to those formed in aphanitic limestone. All these processes are postlithification (mesodiagenetic 

or telodiagenetic). 

Luster mottling is found not only in sandstones having a 

carbonate matrix but also in pure carbcnate rocks, in limestones, and in dolomites and mixed rock types. In carbonate 

rocks this texture is due either to partial dedolomitization of 

dolomite or to parallel optical orientation of crystal grains in 

clusters in which the optical orientation differs from one cluster 

to another. 

Introduction and migration of silica are important aspects of 

diagenesis. 1Silica occurs as chert nodules and layers, spherulitic replacements, authigenic quartz, and as replacement of 

fossil skeletons, especially those of Amphipora, corals, and 

brachiopods. In many rocks, brachiopod shells are only incompletely silicified and consist of a layer of siliceous material enclosing a calcite core. Some, but not all, of the diagenetic silica 

is derived probably from solution and partial replacement (by 

calcite or dolomite) of detrital quartz grains. This process 

is reversible or cyclical in that diagenetically deposited silica 

may in turn be invaded by calcite or dolomite. 

The age of the Martin Formation in central Arizona is Early 

or Middle to early Late Devonian. The beginning of sedimentation of the Beckers Butte Member cannot be dated more 

closely than Early or Middle Devonian on the basis of psilophyte 

flora in the member, although a Middle Devonian age is more 

probable on grounds of regional geology. The upper half of the 

upper unit of the Jerome Member contains many fossils of a 

general Frasnian (early Late Devonian) age and some of late 

Frasnian age. The lower age limit of the Jerome Member 

cannot be accurately defined, and where the boundary between 

the Middle and Late Devonian in the Martin Formation occurs is 

not known at present. 

Study of facies distribution and isopach pattern of the rocks 

of the Martin Formation indicates that a continuous broad shelf 

area extended southwest of the Defiance uplift into central Arizona and that no major land mass was present here, as was suggested by some writers. This conclusion is based on ( 1) the 

areal distribution of the Beckers Butte Member, (2) the distribution and facies character of the fetid and aphanitic dolomite 

units of the Jerome Member, which have specialized sedimentational and complex diagenetic histories, (3) the lateral distri· 

bution of terrigenous siliceous-detrital material in the upper 
INTRODUCTION 3 

ilnit of the Jerome Member, suggesting northeastern and south· 

eastern sources rather than a source in central Arizona, and 

( 4) distribution and composition of fossil faunas in the upper 

part of the upper unit, which suggest a deepening of the sea 

during the closing stages of the deposition of the Jerome Member. 

INTRODUCTION 

LOCATION AND GEOGRAPHY 

The present study concerns the Devonian rocks in 

northern Gila County, southwesternmost Navajo 

County, northeastern Yavapai County, and southernmost Coconino County in Arizona. The geographic 

subdivisions in this part of the State are the following: 

North-central Arizona (Yavapai County), east-central 

Arizona (Gila County), south -central Arizona ( Maricopa and Pinal Counties), and northeast Arizona (Coconino, Navajo, and Apache Counties). 

The Devonian rocks studied in this report lie in 

north -central and east-central Arizona and in a very 

small corner of southwestern Navajo County. A single 

outcrop is situated in Cooonino County (Elden Mountain). However, for convenience the entire area containing outcrops of Devonian rock studied in this report is referred to as central Arizona (fig. 1) . 

Devonian rocks crop out partly as continuous belts 

and partly in scattered localities along the southwestern edge of the Colorado Plateau and in immediately 

adjoining parts of the Basin and Range province of 

Arizona. Southeast of the area Devonian rocks are 

deep in the subsurface, and first crop out in the area 

underneath the Mississippian Redwall Limestone at a 

point about 11h miles southeast of the confluence of the 

White and Black Rivers. Partly because of a regional 

southeasterly dip in this area and partly because of 

the deepening of the bed of the Salt River toward the 

west, the altitude of the belt of Devonian rocks above 

river level increases along the walls of the spectacular 

Salt River gorge to a point north of the bridge of U.S. 

Highway 60 over the 'Salt River, where the base of the 

Devonian section lies at an altitude of about 4,000 feet, 

or 600-700 feet above the bed of the river (fig. 2). The 

base of the section is at an altitude of about 5,200 feet 

in the lower Salt River draw area and along the entire 

length of Canyon Creek, where the section is well exposed along the eastern side of the valley. 

The rocks are well exposed along this entire belt but 

are mostly accessible with great difficulty; so, localities 

at which stratigraphic sections could be measured and 

3!dequately sampled are relatively far apart. The beds 

are horizontal, or very nearly so. 

Farther northwest the Devonian belt converges toward the edge of the Mogollon Plateau and runs close 

to the foot of the Mogollon Rim, where good outcrops 

occur in the valleys of Hunter, Christopher, and the 

upper Tonto Creeks and the valleys of the upper East 

Verde River and some of its tributaries. The base of 

the Devonian section here lies generally at altitudes between 5,400 and 5,600 feet; the differences in altitude 

are due largely to irregularities in the pre-Devonian 

erosion surface. This outcrop belt ends near Pine, 

where the rocks are generally more easily accessible but 

exposures poorer than in the Salt River and Canyon 

Creek area. The beds are either flat or dip gently toward the Mogollon Rim, except in the Christopher 

Mountains south of Christopher Creek, where steeper 

northerly dips are more common. 

Tectonically, the rocks along the entire belt from the 

upper Salt River to Pine form part of the Paleozoic 

foundation of the Colorado Plateau. Opinions differ 

on the exact position of the southwestern boundary of 

the Colorado Plateau. Acoording to Ransome ( 1933) 

and Eardley (1951, p. 141), the belt of Devonian rocks 

here discussed forms part of the Mexican Highland 

region. According to Wilson and Moore ( 1959), it lies 

in a transition zone between the Colorado Plateau and 

the Basin and Range province of southeastern 

Arizona. 

At least in a general way, the southwestern boundary 

of the Colorado Plateaus province is most logically accepted as being in the position suggested by Bromfield 

and Shride (1956, p. 614) because it separates an area of 

virtually undisturbed rocks to the northeast of the 

boundary line from an area of folded, faulted, and uplifted rocks to the southwest. The suggestion of Heindl 

and Lance ( 1960, p. 15) to include a marginal belt of 

the disturbed area in the Colorado Plateaus Province 

seems little justified. 

Southwest of the Colorado Plateau as 'defined by 

Bromfield and Shride (1956), rocks have been much 

disturbed by younger orogenies, and outcrops of Paleozoic rocks-more especially of Devonian rocks-are 

scattered and far apart. This area of disturbed rocks 

includes the rugged mountainous region of the Sierra 

Ancha and the Mazatzal Mountains separated by the 

wide valley of Tonto Creek, the principal tributary of 

the Salt River. The only known outcrops o:f Devonian 

rocks are at Aztec Peak, at an altitude of more than 

7,600 feet. 

South of the Sierra Ancha, stratigraphic sectionssome incomplete-were measured on the south side of 

Theodore Roosevelt Lake and near Globe. Information 

on scattered outcrop areas near upper Pinto Creek and 

in the Superior area was taken from other sources. 

At the northwestern end of the Mazatzal Mountains, 

isolated areas of Devonian rocks crop out southeast of 

the junction of the East Verde and Verde Rivers, where 
4 

I 

34°Jf-. 

of 

~\ 

"'<i' 

~~ c.P../ 

( 

DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

MOHAVE 

0 Kingman 

1----..... 

~ --- I 

I 

I 

YUMA I M 

0 50 100 150 

FIGURE 1.-.Location of area covered by this report. 

\ 

I 

I 

l 
INTRODUCTION 5 

they are best exposed in the Limestone Hills. This area 

can be reached on horseback from Verde Hot Springs. 

South of the Salt River and east of U.S. Highway 60, 

the Paleozoic rocks are buried under the basalts of the 

Natanes Plateau but appear in a few places as inliers, 

where the cover· of volcanic rocks was perhaps thin and 

has been eroded away. Two inliers i1ear Sawmill Creek 

\Yere studied, as was one isolated sec;tion on a hill at 

Ninemile Creek, 10 miles southeast of U.S. Higlnvay 

66. 

West and southwest of Pine and north and west of 

Verde Hot Springs, the Paleozoic rocks are covered by 

an extensive field of volcanic rocks. Devonian rocks 

occur only as small inliers in the valley of the Verde 

River and near Squaw Peak south of Oamp Verde. 

Here, an incomplete section was studied just below 

Squaw Peak, and a more complete one was studied in 

Chasm Creek farther south. 

Devonian rocks occur farther north at Mingus Mountain, where they have long been known in the Jerome 

mining district and where they are easily accessible in 

many places. An almost uninterrupted belt of outcrops 

of Devonian rocks extends northwestward from this 

area to the Grand Canyon, but this belt has not yet been 

studied, except near Jerome and at the junction of Sycamore Creek and Verde River, about 8 miles north of 

Jerome. 

Finally, a small area of Devonian rocks at Elden 

Mountains, north of Flagstaff, has been included in this 

study. Because it is remote from other outcropping 

Redwal l Limestone 

FIGURE 2.- 1\fartin Formation and Redwall Limestone resting on Precambrian complex. North side of Salt River gorge north of crossing of 

U.S. Highway 60, seen from south side. The Martin Formation immediately overlies slope-forming Mazatzal Quartzite. On the slope 

below, the vertical cliffs having columnar structure are diabase; the stratified rocks are Mazatzal Quartzite (A. F. Shride, oral commun., 

1956). 
6 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

rocks of Devonian age, accurate information on the 

nature of these rocks seemed desirable. 

The general distribution of Devonian rocks in pa.rt of 

the area discussed in this report is shown on the geologic 

maps of Gila County and of Yavapai County issued by 

the Arizona Bureau of Mines ('V"ilson and others, 1958, 

1959). 

PREVIOUS WORK 

In the area considered in this report, rocks of Devonian age were undoubtedly first seen in 1871 by geologists of the U.S. Geographical Survey West of the 100th 

Meridian (Wheeler, 1872). Gilbert (1875) and Marvine ( 1875) published brief observations on the stratigraphic succession near Camp Verde, in Canyon Creek, 

and in the Salt River gorge south of Camp (now Fort) 

Apache, but the geologists seem to have included most 

rocks now known to be of Devonian age in the Red wall 

Limestone, the age of which was given as "Upper Carboniferous." Gilbert and Marvine possibly included 

some of the basal sandstones of Devonian age and other 

rocks of early Paleozoic age in their "Tonto sandstone" 

and "Tonto shale." 

The first recognition of the presence of the Devonian 

System in the area was by Reagan (1903), who studied 

the stratigraphy of the Fort Apache Indian Reservation. Under the heading "The Devonian," Reagan described "alternating chert and flint strata followed by 

massive, very fossiliferous light colored, fine grained, 

marble limestone, which in turn is followed by a grit." 

Of fossils he mentioned "Orthis laevis, Spirifer fornaoula and Acervularia davidsoni" and remarked that 

these correspond "very much to the Devonian formations at the falls of the Ohio." Underlying the Devonian sequence Reagan reported 70 feet of "red to brown 

fossiliferous, coarse-grained lime rocks," which he 

placed in the "Upper Silurian," and below these a formation of "coarse- to fine-grained, often crossbedded 

vitreous sandstones and sandy shales, varying in color 

from brown red, purple, and white," which he referred 

to Gilbert's Tonto Shale. Most of these rocks undoubtedly belong to the Devonian System as understood by 

later authors. 

Lee (1905, p. 97'-98) reported very briefly on the 

stratigraphic sections at Roosevelt ("Tonto basin dam 

site") and Windy Hill, where he included the rocks 

immediately above the Apache Group in the "lower 

Carboniferous." He seems to have collected no Devonian fossils. 

Next, Ransome (1915, 1916) identified strata of Devonian age from several places in central Arizona, 

especially the Theodore Roosevelt Dam site and the 

Jerome area. He also referred to and reinterpreted 

Gilbert's earlier observations from Canyon Creek. 

Ransome reported thin-bedded limestones and sandstones or quartzites from Roosevelt, which he correlated 

with the Martin Limestone, described by him earlier 

(Ransome, 1904b) from the Bisbee area in southeastern 

Arizona. However, he observed that the beds at Roosevelt are more sandy and less fossiliferous than the Martin Limestone of the Ray quadrangle. A small fauna 

of Devonian age was reported that, according to Kirk 

( 1931), could be correlated with that of the Martin 

Limestone of Bisbee and that of the Ouray Limestone 

of southwestern Colorado. 

In the Jerome region Ransome (1916, p. 160- 163) discovered 500 feet of "thin-bedded compact limestone" 

containing Devonian fossils. He dated this unit as 

"Devonian, at least in part," but did not assign it to the 

Martin Limestone. A small marine fauna composed of 

corals and brachiopods was reported from these beds. 

Ransome also described a section from the East Verde 

River near the crossing of the road from Payson to 

Pine that he regarded as at least partly Devonian in 

age. This section is at approximately the locality of 

section 32 of the present report. Ransome restricted 

the name Martin Limestone to the predominantly carbonate sequence. The sandstones below this sequence, 

which had already been recognized by Gilbert, Marvine, 

a1id Reagan, he correlated partly with the Tapeats 

Sandstone of Cambrian age and partly with the Troy 

Quartzite, which he believed to be of Cambrian age. 

Another important contribution by Ransome (1916, 

p. 153-154) was his discovery of a thick .sandstone series 

near Aztec Peak in the Sierra Ancha. He considered 

(p. 154) this sandstone to be "the stratigraphic equivalent of the Troy quartzite," but his columnar section 

(Ransome, 1916, pl. 25, section VI) indicates that he 

seemed to regard some of the upper part of this sandstone sequence as a correlative of the Devonian Martin 

Limestone. 

The germ of the concept of the Defiance Positive Area 

is found in a paper by Gregory (1917, p. 18), who stated 

that much of the Navajo country is underlain by 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." 

Reber ( 1922) reported 300-500 feet of limestone in 

the Jerome district, "all or part of Devonian age," 

which he correlated with the Temple Butte Limestone 

of the Grand Canyon. 

Darton ( 1925) summarized some of the earlier observations and added that he found "distinctive strata 

containing Devonian fossils in a wide area of central 

and south-central Arizona including the Salt River 

Basin, Black River Valley, Natanes and Mogollon pia-
INTRODUCTION 7 

teaus" and in several other localities situated outside 

the area discussed in the present report. He was the 

first to recognize a widespread erosional unconformity 

at the base of the Devonian in central Arizona. 

Lausen and Wilson (1925) described reddish-brown 

sandstones, which are locally crossbedded and as much 

as 150 feet thick, from the area south, west., and north 

of Payson and applied to them the name Sycamore 

Creek Sandstone, which was taken from an unpublished 

manuscript by Stoyanow. They reported that Schuchert and Stoyanow found fossil fish remains of Late 

Devonian age in the sandstones and that the sandstones 

are overlain by "thin-bedded, flaggy limestones." 

Stoyanow (1926) gave further details on the Sycamore Creek Sandstone, which he ca1led Sycamore 

Creek Formation, identifying the type locality andreporting the presence of M acropetalichthys. He pointed 

out the significance of these finds for the dating of the 

basal sandstones of the Devonian and rega.rded it as 

doubtful whether, in the absence of faunal evidence, 

any part of the basal sandstones that Ransome had correlated with the Troy Quartzite and Tapoots Sandstone 

might in fact be Cambrian. Stoyanow also noted that 

similar sandstones were widely distributed elsewhere 

in the Tonto and Verde River basins, and he briefly described a Devonian and Mississippian section totaling 

324 feet in thickness from Windy Hill, on the south 

shore of Theodore Roosevelt Lake. 

In 1930 Stoyanow stated briefly that the Devonian 

sequence in northwestern Arizona differed significantly 

from that of southeastern Arizona, and he proposed the 

name Jerome Formation for the northwestern sequence. 

He suggested that it was the equivalent of the Elbert 

Formation and the lower Ouray Limestone of Colorado. 

Hinds ( 1936, p. 32-36) discussed Precambrian and 

Cambrian relationships in central Arizona and referred 

all sandstones overlying Precambrian rocks and underlying Martin Limestone to the Troy Quartzite, which 

he regarded as Cambrian in age. 

Stoyanow ( 1936) described the Devonian stratigraphy near Jerome in somewhat greater detail. He 

redescribed the Windy Hill section and increased his 

figur.e for the thickness of the exposed Devonian part 

of the section to 34 7 feet. He also published observations on the Devonian rocks south of the Salt River. His 

observations on the Elden Mountains section are reviewed on page 44. Stoyanow (1930) gave data in 

support of his limited observations, according to which 

the lithologic character of the Devonian rocks in the 

Jerome area is very different from that of the Martin 

Limestone nea.r Bisbee, and he described the previously 

named Jerome Formation in greater detail. He reduced 

the former Sycamore Creek Sandstone or Formation to 

the strutus of a member and reported a. sandy facies in 

the upper part of the Jerome Formation north of 

Jerome, whieh he referred to as the "Island Mesa beds." 

Stoyanow's proposed stratigraphic terms are critically reviewed on page 15. It is of interest to note here 

that he reported fish remains in several horizons in the 

lower part of the proposed Jerome Formation and coral 

and stromatoporoid "reefs" in the upper part. 

Furthermore, Stoyanow reported units equivalent to 

the lower part of the Ouray Limestone near Globe on 

the basis of finds of Oamarotoechia endlichi on Pinal 

Creek. The section in this locality had been described 

in some detail by Stauffer (1928b), who referred all 

Devonian rocks to the Martin Limestone. 

In the same paper Stoyanow ( 1936) proposed the 

name Mazatzal Land for an "ancient land in central 

Arizona," which he believed had been present throughout much of Paleozoic time. 

Stoyanow ( 1942) summarized his views on the Paleozoic paleogeography of Arizona. He ventured the 

opinion, as had Darton ( 1925), that Devonian and Mississippian rocks thin considerably towards central Arizona both from the southeast and from the northwest. 

This thinning was described as most noticeable in Gila 

County in the general area between Globe, the upper 

Salt River, and the East Verde River near Payson and 

Pine. This area is now occupied mostly by Precambrian rocks, which are traversed by Tonto Creek and 

are thickest in the Mazatzal Mountains to the west of 

Tonto Creek and in the Sierra Ancha to the east. 

Stoyanow maintained that as this Precambrian oomplex 

was approaehed, not only the thickness of the Devonian 

rocks decreased but also the facies beeame more sandy, 

as shown on his map (1942, pl. 5, fig. f). He therefore 

concluded that this area of central Arizona represented 

an old positive area-Mazatzal Land-that had persisted from Preeambrian time. A narrow strait to the 

north, northeast, and east of Mazatzal Land connected 

the northwestern (Cordilleran) and southeastern 

( Sonoran) seas, where d,eposition was more continuous 

and the deposits were thicker. The strait was not continuous but was interrupted by a narrow rise near the 

present headwaters of Tonto Creek. The rocks deposited in the southeastern part of this strait were correlated with the Martin Limestone of southeastern Arizona. The name Jerome Formation was used for the 

Devonian strata northwest of Mazatzal Land. 

In several publications Huddle and Dobrovolny 

(1945, 1946a, 1952) described the Devonian stratigraphy between the upper Salt River and Pine. Their 

results are more fully discussed in appropriate places 

in this report. In general, these authors supported 

Stoyanow's paleogeographical conclusions, although 

they considerably reduced estimates of the size of Mazatzal Land. Huddle and Dobrovolny measured many 
8 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

geologically important Devonian sections and assigned 

all rocks of that age to the ":M:artin formation"; the predominant rock types, according to their descriptions, 

are limestone and dolomite limestone. In a separate 

publication the same authors (1946b) described briefly 

a bioher1nal facies as common in the upper part of their 

Martin Forn1ation. Huddle and Dobrovolny's conclusion was that Mazatzal Land had been a l~rge island 

from which three prominent prongs projected northeastward-named Pine Ridge, Christopher Mountain 

Ridge, and Chediski Ridge-that determined in an important way the character of the Devonian rocks. These 

ridges probably subsided northeastward under a cover 

of younger sediments in a trough termed the ''Mogollon 

Sag." The l\1:ogollon Sag corresponds in position to 

Stoyanow's central Arizona strait (not so named by 

him), but it probably received a greater thickness of sediment. Huddle and Dobrovolny emphasized again the 

progressive increase in arenaceous matter in the Devonian sedimentary rocks toward the Mazatzal Land. 

Furthermore, they described the Defiance uplift as a 

narrow northeast-trending ridge separated by a basin 

from the Zuni uplift, which trends parallel to the Defiance uplift. 

In the meantime different ideas were being developed 

by Eardley (1949, 1951) and by Mcl{ee (1951). From 

the literature as well as many unpublished data, Mcl{ee 

compiled isopach maps for the Devonian and other 

Paleozoic systems. On the basis of the maps, he rejected 

the concept of Mazatzal Land and believed that central 

and southwestern Arizona were once covered with Devonian and Mississippian deposits that were removed by 

erosion following uplift, probably as late as Miocene 

and Pliocene. He found confirmation of this view in 

the large number of pebbles and cobbles derived from 

the Paleozoic in upper Tertiary gravels along the southern margin of the Colorado Plateau. (See also Price, 

1950.) The area of Stoyanow's Mazatzal Land is thus 

considered to he a basin of sedimentation containinO' b 

original thicknesses of Devonian rocks of 400-500 feet. 

More or less simultaneously, Eardley (1949, 1951) 

made a very similar interpretation. He called the Central Arizona sedimentation area "Arizona Sag," which 

represented a semistable area between the Cordilleran 

and Sonoran geosynclines and the more stable positive 

areas in northeasten1 and south western Arizona. The 

northeastern area was called "Defiance Positive Area" 

by Mcl{ee, and on his maps this area occupies a dominant position underlying the eastern half of the Colorado Plateau in Arizona, ineluding mueh of the Blaek 

Mesa basin. MeKee diseounted eviclenee of increasing 

sandiness of the Devonian rocks in central Arizona. 

More recently Anderson and Creasey (1958) gave a 

brief description of the Devonian rocks of the Jerome 

distriot, which they described under the name of l\{artin 

Limestone. They divided the Martin Limestone at 

.Jerome into four stratigraphic units composed mostly 

of dolomite, dolomitic limestone, limestone, and some 

interbeds of siltstone and shale. The sequenc.e rests on 

brmvn erossbedded coarse-grained sandstone, which 

Anderson and Creasey correlated tentatively with the 

Tapea.ts Sandstone of Early and Middle Cambrian age 

in the Grand Canyon area, as did Stoyanow before 

them. This view was supported by Krieger ( 1959). 

Lehner ( 1958) described the Devonian rocks of the 

Clarkdale quadrangle that in,cludes portions of the 

Jerome district. In his descriptions and subdivisions, 

Lehner follo-wed Anderson and Creasey (1958) very 

closely. He classified the basal sandstone as Ta peats 

(?), and he recognized the same four subdivisions of 

the Martin Limestone, which he designated as units A, 

B, C, and D, respectively. . 

The diseovery of an isolated Devonian outcrop at 

Elden Mountain, northeast of Flagstaff, w"as made by 

Brady ( 1933, 1934). Much earlier a large tilted block 

of Paleozoie sedimentary rocks surrounded by volc.anie 

rocks was mapped in this area by Robinson ( 1913), 

who believed all the pre-Pern1ian rocks to be Mississippian in age (Red wall Limestone). Brady reported 

125 feet of sandy limestone and sandstone below the 

Redvmll Limestone. Finds of fish plates suggested to 

him that the roeks correlate 'vith Stoyanmv's Sycamore 

Creek Formation on the East Verde River. Additional data on the East Verde River locality were given 

by Stoyanow ( 1936, p. 501) ; according to him, the section is 148 feet 10 inches thick and consists entirely of 

li1nestone. Coral and brachiopod remains were reported from some horizons. He also described some 

arthrodiran plates from these beds but did not name 

them. 

Tur11er ( 1958) included rocks as far south as the 

:Mogollon Rim in his discussion of the Devonian of the 

Black Mesa basin. He believed that broad facie8 

changes take place in the southen1 part of the basin and 

that although the roeks are no'v included in the Martin 

Limestone, a more appropriate non1enclature would 

have to be developed as explorn;tion proceeds. Tun1er 

further called attention to reports of "petroliferous 

odor" of Devonian rocks along the Mogollon Rim in 

the Pine-Payson area, and he accordingly included 

this area a1nong those considered favorable for the occurrenee of oil and gas. 

More recently, Elston (1960, p. 28-29) briefly summarized the Devonian paleogeography in northeastern 

Arizona, but his discussion included only a small part 

of central Arizona. He stated that the existence of 

Mazatzal Land seems to have been conclusively established, and on his isopach map (Elston, 19·60, fig. 5) he 
INTRODUCTION 9 

showed thickening of the Devonian rocks north of Mazatzal Land in the "Holbrook Sag," which seems to be 

identical with the "Mogollon Sag" of Huddle and 

Dobrovolny (1952). 

Finally, Brown and Lauth (1960) regarded the 

Devonian rocks between the Mogollon Rim and Holbrook as a "potential [oil] producing area." They referred to an extensive depositional trough south of 

Flagstaff that extends southeastward to theN e"\Y Mexico 

State line, where Devonian rocks may be 50~600 feet 

thick. For this feature the name "St. Jolms Sag," 

coined by Kelley ( 1955) for a post-Devonian trough, is 

preferred. Brown and Lauth suggested that reefs may 

be present in this trough. 

In the same year, Cross and others (1960, p. 87) produced a relief map purporting to depict the paleogeography of Arizona in Devonian time. Outside the 

Defiance uplift this map showed one large and one 

small island in central Arizona, three small islands 

in the Grand Canyon area, and a land mass and a small 

island in the southwestern part of the State. 

Before the present investigation, fossils in the Devonian rocks of central Arizona received little systematic attention. Small collections--identified by Girty, 

Kindle, and IGrk-were mentioned by Ransome (1916) 

and by Darton ( 1925). Stoyanow ( 1936) listed 24 

species, mostly corals and brachiopods, from his Jerome 

Formation. The fish remains from the Elden Mountain section were described by Hussakof (1942). In 

1948, Stoyanow described a small unique fauna composed of four new genera of pelecypods and gastropods 

from the "Island Mesa beds" but gave no information on their locality and exact position in the sequence. 

Paleontologic information from scattered localities between the Salt River and East Verde River was given 

by Huddle and Dobrovolny ( 1952). 

The age of the marine faunas had been established 

as Late Devonian, comparable to that of the Independence Shale of Iowa. (See also Cooper, 1942.) A 

well-preserved psilophyte flora was discovered near the 

base of the Devonian section in the upper Salt River 

area and was reported by Teichert and Schopf ( 1958). 

This flora indicated that the lower part of the Devonian 

sequence is as old as Middle or possibly Early Devonian, 

although no break in the seqnenee could be discovered. 

SCOPE OF PRESENT INVESTIGATIONS AND METHODS 

OF STUDY 

The present investigations began in 1953 on behalf of 

the Shell Oil Co. as a contribution toward evaluation of 

the oil possibilities of the Black Mesa basin. For this 

purpose the Devonian and Mississippian rocks along 

the southern and westen1 periphery of the basin were 

studied in some detail. In 1956 the Shell Oil Co. released the results of these studies to the U.S. Geological Survey, and additional fieldwork was done in that 

year and again in 1957. During 6 weeks in 1956 I was 

assisted in the field by R. L. Harbour. Most o:f the laboratory work was completed on ,July 1, 1960. Manuscript and illustrations were also eompleted on July 1, 

1960, but some minor additions and changes were introdneed on the basis of field observations made in Oetober 

1960 and in April 1961. It was impraetieable to introduce references to any publications that appeared later 

than April 1961. 

The present study emphasizes detailed investigations 

of measured sections, combining field observations with 

microseopic examination of thin sections and reexamination of hand specimens together with some laboratory 

determinations, such as Ca/Mg ratio detenninations, 

heavy-mineral analyses, mechanical analyses, and insoluble residue studies. 

From the review of previous work in central Arizona, 

given in the preceding section, the following seemed to 

be important points for inquiry: 

1. The question of the existence of "Mazatzal Land" 

contrasted ,vith that of the "Arizona Sag." 

2. The extent of the "Defiance Positive Area" in 

Devonian time. 

3. The probable nature of the Devonian sedimentary 

rocks underlying the Black Mesa basin. 

4. The nature and age of the basal Devonian rocksespecially sandstones-and their relationships to 

the Troy Quartzite and the Tapeats Sandstone. 

5. The reported occurrence of reefs and bioherms in the 

Devonian. 

To get answers to all these questions required a broad 

regional study of the Devonian rocks of central Arizona 

based on detailed lithological and paleontological studies of reasonably closely spaced stratigraphic sections. 

Selection of sections for measurement and detailed 

study was of necessity determined by the n~ture o£ the 

outcrops and their accessibility. Only part of the area 

under investigation is topographically mapped at a 

scale of 1: 62,500. For areas not so mapped use was 

made of the following: Map of San Carlos Indian Reservation, 1945, 1: 125,000, published by the Office of 

Indian Affairs; map of Fort Apache Indian Reservation, 1938, 1: 125,000, published by the Office of Indian 

Affairs; map of Tonto National Forest, 1938, 1: 250,000, 

compiled by the Albuquerque office of the U.S. Forest 

Service. 

During fieldwork in 1956, aerial photographs prepared by the Army Map Service at a scale 1:50,000 

were used with much success in locating suitable outcrops. 

As most geologists will agree, the results o£ measuring and interpretation of stratigraphie sections are 
10 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

somewhat subjective. Many personal factors and variables, such as weather, temperature, fatigue, time limitations, and others, enter into the task. For this reason no two geologists will ever describe one and the 

same stratigraphic section in identical terms, and even 

one observer who measures the same section twice in 

different field seasons will note differences and discrepancies in the two descriptions. The subjective nature 

of many stratigraphic techniques has been discussed 

recently by Schenck and Graham ( 1960). 

Decisions of an interpretative nature based on only 

superficial examination of rocks must continuously be 

made in the field in order that a logical grouping of 

rock units in a section may be determined. Most rock 

subdivisions in stratigraphic sections are somewhat arbitrarily and subjectively defined in the field, and those 

in one section are not necessarily fully comparable qualitatively with those in another section. Nevertheless, 

a subdivision in this sense should be the smallest group 

of strata or beds-in some places, only one bed-within 

a formation that can be recognized in the field. Such a 

rocks subdivision, herein called a subunit, should ideally 

consist of only one type of rock, well defined in regard 

to composition, color, texture, hardness, and weathering, 

or it may consist of two types of rock that are so defined and may either alternate regularly or be subordinate one to the other. Examples of the last mentioned type of rock subunit are a dolomite having scattered shale partings or a limestone containing chert 

nodules. 

Rock subunits must be defined in the field on the 

basis of superficial examination with a hand lens, aided 

perhaps by hydrochloric acid or simple stain tests, but 

later more detailed laboratory study of samp:J.es may 

reveal that what had appeared as a subunit in the field 

may consist of more than one rock subunit. 

Measurements of sections were made mostly with the 

help of an Abney level, which either was attached to a 

5-foot rod or was held in the hand ; correction for angle 

of dip of the beds was made where necessary. In 

places, where slopes were very smooth, a measuring tape 

was used. Samples were taken, as a rule, not at regular 

intervals but insofar as possible from every stratigraphic subunit. Two or more samples were generally 

collected from subunits thicker than 15 feet. Except 

those samples collected from relatively inaccessible sections, individual samples weighed 250-500 grams, 

enough for all ordinary laboratory investigations. Not 

all samples were later used, but no decision regarding 

the later use of samples was made in the field. 

Some sections measured in 1953 were studied and 

sampled in less detail than the sections measured in 

1956. Also, sample splits available from collections 

made during the 1953 field season were generally too 

small for laboratory tests. 

Sketch maps (pl. 32) show the location of all measured sections. They serve to facilitate efforts of others 

to find all localities mentioned and described in this 

report if used with the specified base maps. 

Thin sections were made of all samples, and information derived from them has been incorporated in 

the section descriptions. Thus, almost all grain-size 

estimates, both of detrital and or carbonate rocks, are 

based on thin -section observations. The Wentworth 

scale was used for all rocks, including carbonates. 

Use of different scales ·as advocated, for example, by 

DeFord (1946) and by Folk (1959), is impractical, 

especially where detrital-siliceous rocks alternate with 

carbonate rocks or where carbonate rocks contain appreciable amounts of detrital siliceous material. Both 

situations occur in many places in the Devonian rock 

sequences of central Arizona. Also, where grain sizes 

are shown graphically on plotted sections, as in this 

report, introduction of different scales for clastic siliceous and for carbonate rocks would be confusing. 

Analyses of many rock samples for calcium and magnesium content were obtained according to the method 

described by Shapiro and Brannock ( 1957). The results were recalculated in MgO percent of total carbonate and are so represented in the graphs. 

Insoluble residues were prepared and mechanical 

analyses were made of selected rock suites, and the 

heavy minerals were separated in several sandstone 

samples. 

Measured sections were plotted so as to show at a 

glance as many ~physical properties of the rock as possible. The following rock characteristics may thus be 

read directly from the diagrams in plates 28-31 for 

each rock subunit distinguished in the field : 

1. Lithology-through use of 31 rock symbols. 

2. Thickness. 

3. Bedding. 

4. Quality of exposures. 

5. Fossil content-through separate symbols for 17 fossil groups, important particularly for correlation 

and for environmental interpretations. 

6. Grain size in terrigenous clastic rocks and crystallinity scale in carbonate rocks, both graphed according to the Wentworth scale. 

7. Approximate color value and hue according to the 

standard "Rock -Color Chart." 

All subunits in all plotted sections are numbered, and 

additional details for each subunit can be found in the 

formal section descriptions on pages 105-169. Ref-
INTRODUCTION 11 

erence to the section descriptions is especially recommended for fossiliferous beds because the fossil symbols 

merely indicate presence of -a particular group of fossils but not their relative abundance or state of preservation. Thus the symbol for brachiopods may indicate 

a few brachiopod fragments or a rich well-preserved 

fauna. Information on this point, together with listings of species where available, is presented in the section descriptions. 

COLOR OF ROCKS 

Pettijohn (1957, p. 346) remarked that "more emphasis is placed on the color of shales than most sedimentary rocks," and even so, few results of research on 

the causes and significance of the color of rocks of any 

kind have been published. Patnode (1941) showed 

that the color of shale is related to reduction number 

and nitrogen content and hence in some way to the 

amount of contained organic matter, although he 

measured reflectivity-that is, color value-rather than 

color as such. MacCarthy (1926) studied the relationship between the FeO /Fe20 3 ratio and the color of 

rocks-mostly of clay, shale, and slate but including 

some sandstone and limestone. He found that colors 

in the red, yellow, orange, and blue hues are related 

to the state of oxidation of the iron, but he did not evaluate his results geologically. 

Danchev (1958) pointed out that color in sedimentary rocks may be either "hereditary" (determined by 

the color of the rock or rocks from which sedimentary 

particles are derived) or diagenetic . (determined by 

secondarily formed mineral substances). 

Weller (1960, p. 129-140) is among the few who 

have given color more than a brief mention in textbooks. He discussed at some length the color-forming 

role of organic matter and of iron compounds and the 

origin of blue and green colors. 

Krynine (1948, p. 145) called color a "powerful tool" 

in describing rocks, and more detailed study and 

proper interpretation of rock colors will undoubtedly 

sometime be recognized as important aids in the understanding and reconstruction of sedimentary and diagenetic environments. Although investigations of this 

nature are beyond the scope of this report, considerable 

attention has been paid to accuracy of color terminology, artd a few special comments are offered on the 

method of representing colors in plotted sections. 

Widespread use of subjective color terminologies, 

which differ among authors, is an obstacle to comparison of color data contained in different publications. 

The situation has probably improved only slightly 

since DeFord (1944) called color description by geologists "completely anarchistic." 

In the present report, color of rocks is described in 

terms of the "Rock-Color Chart" by Goddard and 

others (1948), which, Weller's objections {1960, p. 140) 

notwithstanding, is the only presently available tool 

for objective rock description. (See also Grunau, 1959, 

p. 6.) All colors were identified from hand specimens 

in the laboratory under unifonn lighting conditions. 

This control insures a degree of uniformity of color 

terminology that is impossible to achieve in the field. 

Some consistent discrepancies occurred between color 

determinations made in the field and in the laboratory. 

Commonly, a medium-gray rock having a color chart 

value N5 was described in the field as dark gray ( N3) ; 

and a dark-gray rock having the value N3 was described as black (Nl). A high degree of subjectivity 

also is the rule in field identifications of the red and 

yellowish-red hues made without use of the color chart. 

Thus, pale red is generally identified as pink, and a 

wide variety of yellowish-red hues are called buff. 

Shales described as green are as a rule some shade of 

olive and thus have a yellow rather than a green hue. 

Sedimentary rocks are rarely, if ever, green. 

Field determinations of colors made without the use 

of a color chart may differ greatly, depending on conditions under which they are made. The observer's 

judgment of color hue, saturation, and value of one and 

and the same rock will differ according to cloudiness, 

time of the day, and conditions of illumination. Nonscientific color recognition, as it still largely prevails 

in geological practice, has been aptly described by Boas 

(1959,p.6): 

When we speak of the color of an object as that color seen by 

normal vision, under certain illumination, at a given distance, 

we are stating how to observe the color. We are admitting that 

the color seen is relative to a number of circumstances which 

can be varied independently of one another and that the sensory 

datum is a function of them all. 

The colors of Devonian rocks of central Arizona are 

almost entirely in the red and yellowish-red hues and 

in the neutral gray axis, although some rocks range 

both into the yellow and greenish-yellow hues and into 

the red-purple hue. Such common field identifications 

as pink, brick red, purple, and cream are in the red 

hue; buff, tan, cream, and brown (most shades) are in 

the yellow-red hue. Most of the yel1ow hues are commonly identified as green. 

In the descriptions of stratigraphic subunits, colors 

have been identified with the help of the "Rock-color 

Chart" ·according to hue, color value, and chroma. 

Thus, in the combination 5R 6/2, R stands for red hue, 

and the number 5 indicates an intermediate hue-red 

hues are valued from lR, which is close to the purple 

hue, to lOR, which is close to the yellow-red hue. The 

numeral 6 indicates the relative lightness of the rock, 
12 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

which is rated 1 on the black end and 10 on the white 

end. The numeral 2 indicates color saturation 

(chroma) -pale colors are indicated by 2, intermediate 

saturation by 4, and bright colors by 6. 

Lack of a color symbol in the description of a subunit 

indicates that either no sample or no sample adequate 

for exact color description was available for laboratory 

study. 

All three color properties cannot be indicated by symbols on a plotted section, and only hue and value (lightness) are shown. Hue is indicated by the width of a 

strip on the left hand side of the plotted column in such 

a way that colors of the gray axis are shown as very thin 

strips whereas hues from purple to yellow are indicated by increasing widths of the strip. Color values 

are indicated by shading and hatching. The general 

color of a subunit can thus be estimated at a glance by 

remembering that wider strips indicate inereasingly 

brighter hues from gray through purple, red, and yellow and that the degree of shading of. the strip roughly 

indicates the lightness value of the color, black representing the value of medium dark gray and darker and 

absence of shading representing a very light gray value. 

Omission of saturation (chroma) on the diagrams 

means that for some samples somewhat different colors 

are grouped together such as pale brown (5YR 6/2) 

and light brown (5YR 5/6). The symbol for both these 

colors on the plot1ted sections would be the same. 

For mottled rocks the symbol indicating the predominant color was chosen. 

HISTORICAL SUMMARY AND EVALUATIONS OF 

STRATIGRAPHIC NOMENCLATURE 

The number of stratigraphic formations which has 

been proposed for rocks of Devonian age in Arizona is 

not great. Because they have been named over a long 

period of time by geologists working in widely separated parts of the State, however, a certain laek of coordination is noticeable. In the following discussion, 

the history of stratigraphic nomenclature of Devonian 

rocks in Arizona will 1

be briefly reviewed and critically 

appraised as far as possible. 

NORTHERN AR.IZONA 

Walcott (1880) was probably the first to recognize 

Devonian rocks in Arizona, when he reported 100 feet of 

"sandstones and impure limestones" of this age in the 

Grand Canyon. In 1890, he named this sequence Temple Butte Limestone hut did not describe it in greater 

detail. Walcott ( 1883) earlier observed that the Devonian rocks in the Grand Canyon have irregular 

thickness and are loeally absent. This observation was 

eonfirmed by N able ( 1914) . Later, N able ( 1922) gave 

the thickness of the Devonian section at the Bass Trail, 

Grand Canyon, as 75 feet, all of which was reported as 

limestone with the exception of 10 feet of magnesian 

limestone at the top. . 

In 1934, McKee measured the type seetion at Temple 

Butte (see Stoyanow, 1936, p. 503) and reported 77 

feet of limestone, sandstone, and shale. McKee ( 1939) 

deseribed briefly the Temple Butte Formation in the 

lower Grand Canyon area, where he reported- thicknesses of 7 43 feet at Meriwitica Canyon and of 1,272 

feet at Grand Wash Cliffs. 

In 1953 I measured a thickness of 84 feet of Temple 

Butte along the Kaibab Trail where the rocks are composed entirely of dolomite and calcitic dolomite. No 

limestone oecurs in this section, and the Devonian rocks 

in the Kaibab Trail part of the Grand Canyon are better referred to as the Temple Butte Formation. 

An attempt to extend the name Temple Butte, to beds 

lying outside the Grand Canyon area was made by 

Reber (1922), who proposed to apply the name to the 

Devonian rocks of the Jerome district. In this application he was :followed, son1ewhat diffidently, by Ransome 

(1933). 

In the area south of the Grand Canyon, Brady (1933, 

1934) discovered a sequence of Devonian age at Elden 

Mountains that had previously been included in the 

Mississippian (Robinson, 1913). Hussakof (1941, 

1942) named these rocks the Mount Elden Fonna.tion 

and determined their age on the basis of fossil fishes as 

early Late Devonian. Restudy of this section in 1956 

(see n1easured section 44 of this report) showed that it 

consists entirely of dolomitic rocks that are lithologically very similar to the rocks of the upper unit of the 

Jerome Member, Ma.rtin Forma.tion, of this report and 

to those of the Temple Butte Formation on the Kaibab 

Trail. No new stratigraphic name seems to be required 

for the sequence at Elden Mountains. 

SOUTHERN ARIZONA 

The seeond rock unit of Devonian age named in Arizona was the Martin Limestone. Ransome (1904c, p. 

33) named this unit from Mount Martin on Escabrosa 

Ridge, southwest of Bisbee, Ariz., and stated that it has 

a thickness of 340 feet there. The most characteristic. 

rock, according to Ransome, is a "dark -gray hard compact limestone," commonly fossiliferous, containing 

minor amounts of lighter gray limestone -and some calcareous shales "of a decided pinkish tint." Petrographically, the formation was stated to be a fairly pure 

calcium carbonate. 

Fossil collections from the Martin Limestone were 

described in the same paper by H. S. Williams (Ransome, 1904c, p. 35-42), who eoncluded that the fauna 

was most probably Middle Devonian in age. All of 

Ransome's collections eame from localities in the central 

and northwestern parts of the Bisbee quadrangle. 
INTRODUCTION 13 

In 1916, Ransome extended the name Martin Limestone to rooks lying beyond the Bisbee quadrangle in the 

Tombstone area, in the Ray and Globe quadrangles, and 

near Theodore Roosevelt Dam. 

Darton ( 1925, p. 57-62) described under the heading 

"Martin limestone" all Devonian rocks in central and 

southeastern Arizona. 

Stoyanow (1936) extended the name Martin Limestone from Bisbee to rocks lying as far north as Globe 

and Theodore Roosevelt Dam. 

The type section of the Martin Limestone does not 

seem to have been restudied or redescribed since the time 

of Ransome's studies ( 1904b) . In 19·5,3 and again in 

1956, I paid brief visits to the type locality of the Martin Limestone at Mount Martin near Bisbee and measured and sampled part of the formation in May 1956. 

The typical Martin Limestone is almost entirely a 

medium-gray to medium dark-gray aphanitic to finegrained limestone. (See fig. 3.) Dolomite is entirely 

subordinate in the Martin Limestone, occurring only 

in the uppermost 20-30 feet. "Rock-color Chart'' values are N 4 to N 5, although in the field one would be 

inclined to describe the rock as dark gray. The lower 

part of the formation is generally thin bedded; the upper part is thicker bedded. Fossils occur at least 

throughout the upper two-thirds of the formation, with 

the exception of the uppermost 50-60 feet, which seems 

to be unfossiliferous. Among the larger fossils, brachiopods predominate. Microassemblages include many 

calcispheres, ostracodes, and unidentified fragmentary 

remains (pl. 15, fig. 3; pl. 16, fig. 3). 

From the Bisbee area generally northward, important facies changes take place. In the Tombstone area, 

only little more than 20 miles to the northwest. Gilluly (1956) described a Devonian section 229 feet thick 

that is composed of nearly 50 percent shale, more than 

10 percent sandstone, and only 30 percent blue-gray to 

gray limestone. In the Dragoon Mountains, about 30 

miles north of Bisbee, the Devonian section is a mixed 

one composed of sandstone, limestone, and dolomite 

( Gilluly, 1956) . In the Chiricahua and Dos ·Cabezas 

Mountains, the Devonian consists of alternating shale 

and limestone for which Sabins (1957) proposed the 

name Portal Fonnation. Epis, Gilbert, and Langenheim (1957) gave the name Swisshelm Formation to 

the Devonian sequence in the Swisshelm and Pedregosa 

Mountains, which there consists of siltstone, marl, sandy 

dolomite, and limestone. 

The dark limestone facies of Bisbee, therefore, probably cannot be traced farther north than the Tombstone 

area, where it is subordinate in the section to clastic 

rocks. In the rest of Cochise County, the Devonian section consists entirely of dolomite, sandstone, and shale. 

Pye (1959, p. 29) regarded the Swisshelm Formation 

as representing a transitional sandy facies between a 

western carbonate facies of the Martin and an eastern 

fine-clastic facies of the Percha Shale. He suggested 

that the Portal could be included in the Percha. 

The suggestion has been made to restrict the name 

Martin Limestone or Martin Formation to the upper 

part of the Devonian section in some areas of southern 

Arizona. Thus, Stoyanow ( 1936, p. 488) proposed the 

name Picacho de Calera Formation for a sequence of 

sandstone, limestone, and dolomite underlying the restricted Martin Limestone in the Picacho de Calera 

Hills, 25 miles northwest of Tucson. This area is outside that discussed here. 

The Santa Rita Limestone of Stauffer ( 1927, 1928a) 

of Middle ( ? ) Devonian age is too ill defined and poorly 

known to be critically evaluated, as was pointed out by 

Stoyanow ( 1936, p. 495). 

CENTRAL ARIZONA 

Ransome (1916) was the first author to apply the name 

Martin Limestone to rocks extending into central Arizona. In the Globe quadrangle Ransome noted that 

"the beds here separated as Martin limestone" may be 

divided into a lower division of hard compact light yellowish-gray unfossiliferous limestones, which are sandy 

in their lower part, and into an upper division of darkgray to yellowish-gray limestones which contain shaly 

partings. Only the upper division is fossiliferous. 

The section at Theodore Roosevelt Dam was described 

in somewhat similar terms, although it is less fossiliferous. Fossil determinations by E. M. Kindle are 

quoted that support a Late Devonian age for the Martin 

Limestone fauna, a view which has been confirmed by 

all later investigators. 

Ransome briefly described the Devonian sequences on 

the East Verde River near the Payson-Pine road and 

those near Jerome, but he did not refer to them directly 

as Martin Limestone. He remarked, however, that the 

lower part of the Devonian section at Jerome resembles the lower part of the Martin Limestone at Ray. In 

1933, he referred to the same section as Temple Butte ( ? ) 

Limestone. Lindgren ( 1926) left these rocks unnamed. 

Stoyanow (1936), as has been stated, applied the 

term "Martin limestone" to the Devonian rocks in the 

Globe area and at Theodore Roosevelt Lake, but he 

doubted the applicability of the term "limestone" in the 

Globe area, because here the Devonian rocks contain 

some arenaceous material. 

Short and others ( 1943), in a study of the Devonian 

of the Superior area., retained the name Martin Limestone but divided the formation into three members: 

(1) a lower dolomite member, (2) a middle yellow limestone member, and (3) an upper yellow shale member. 

One of the coauthors of that report, E. N. Harshman, 
14 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

suggested that the lower dolomite member be named the 

"Crook formation," thus by implication restricting the 

name Martin Limestone to the upper two members. 

Huddle and Dobrovolny (1945; 1952, p. 73), in a 

study that included the Devonian rocks of central Arizona between the upper Salt River and Pine, preferred 

the name "Martin formation" to "Martin Limestone" because Devonian strata there contain 40-50 percent sandstone and shale. The name "Martin limestone," however, was retained by Peterson, Gilbert, and Quick 

(1951) for rocks in the Castle Dome area, by Peterson 

(1954) for those in the Globe area, by Bromfield and 

Shride (1956) for those in the San Carlos' Indian Reservation, by Gilluly (1956) for those in Cochise County, 

and by Anderson and Creasey ( 1958) for Devonian 

rocks in the Jerome district. In the Devonian correlation chart published by the Geological Society of America (Cooper, 1942), the name Martin Limestone was 

used for southeastern Arizona only. McNair (1951) 

used the name Martin Limestone for Devonian ·rocks 

found as far north as the southern Hurricane Cliffs on 

the north side of the Grand Canyon. 

In addition to the stratigraphic units discussed in 

the foregoing paragraphs, the following formations 

established or used by Stoyanow for Devonian rocks in 

central Arizona deserve special attention and discussion: Sycamore Creek sandstone, Jerome formation, 

Island Mesa beds, and Lower Ouray formation. 

SYCAMORE CREEK SANDSTONE OF LAUSEN AND WILSON (1925) 

'The name Sycamore Creek Sandstone was introduced by Lausen and Wilson (1925), who credited it to 

an unpublished manuscript by Stoyanow. Lausen and 

Wilson described the unit as consisting of generally 

dull reddish-brown sandstone and some buff-colored 

beds that are made up of coarse quartz cemented by iron 

oxide and calcium carbonate. Crossbedding is locally 

common, as are pebbly layers. Finer grained beds 

yielded fish remains, which were later described by 

Stoyanow (1936). Lausen and Wilson reported "thinbedded, flaggy limestone" resting above the Sycamore 

Creek Sandstone and containing a small Devonian invertebrate fauna in the higher parts. The thickness 

of the Sycamore Creek Sandstone was given as "seldom 

over 150 feet." 

Stoyanow ( 1926) identified the type locality of the 

unit as "Sycamore Creek, an affluent of the East Verde 

River, flowing southeastward from the divide near 

Nat ural Bridge, which separates it from Pine Creek, 

another tributary of the East Verde." The identification of the locality is further confirmed by reference to 

Ransome's brief description (1916, p. 159-160) of the 

same section. Thus, the Sycamore Creek in question 

is clearly the one that originates approximately 2 miles 

west of the center of Pine quadrangle and flows south 

then west and southwest until it joins the East Verde 

River close to BM (bench mark) 4523 a:t the bridge on 

the Pine-Payson Road. Well-exposed outcrops of Devonian rooks occur in the valley of the upper Sycamore 

Creek east of BM 5735 and BM 5274 (see measured 

section 33 of this report), but the outcrops described by 

Ransome and by Stoyanow are undoubtedly those found 

immediately north of the East Verde River. 

The sandstone that crops out in roadcuts in the East 

Verde valley was correlated by Ransome ( 1916) with 

the Tapeats Sandstone of Early and Middle Cambrian 

age, but Stoyanow (1926, p. 313) reported finds of 

M acropetalichthys in the upper part of this sandstone 

and concluded that, in the absence of faunal evidence 

of Cambrian age for the lower part, the entire sandstone unit should he regarded as of Devonian age. 

Stoyanow stated that a similar sandstone containing 

arthrodiran remains occurs in the Verde and Tonto 

basins and had formerly been identified as Tapeats 

Sandstone of Cambrian age; he proposed to designate 

this unit as Sycamore Creek Formation. He does not 

refer to the previous use of Sycamore Creek Sandstone 

by Lausen and Wilson (1925). 

In 1936 Stoyanow gave further details on this unit, 

which he then proposed to call Sycamore Sandstone 

Member of the Jerome Formation (1936, p. 499). He 

stated that on the East Verde River this member rests 

directly on the Tapeats Sandstone, though he recognized that the "discrimination between the Cambrian 

and Devonian on the basis of lithology is rather difficult." He did not indicate thicknesses for the Devonian and supposedly Cambrian parts of the basal sandstone. He emphasized the wide distribution of fish 

( arthrodiran) remains not only in the basal sandstone 

unit but also in stratigraphically higher sandstone in 

this and other stratigraphic sections. 

Peculiarly, in 1942 Stoyanow assigned the same basal 

sandstones on the East Verde River to the Tapeats 

Sandstone (Stoyanow, 1942, p. 1268). Plate 1, figure 

1, of the same paper shows Tapeats Sandstone resting 

on granite and Jerome Formation "with basal limestone 

resting directly on the Cambrian." This locality is discussed in the description of the Beckers Butte Member 

of this report (p. 29). 

The name Sycamore Creek Sandstone or Sycamore 

Sandstone Member has not been used in the literature 

dealing with central Arizona since Stoyanow's last discussion of it. Huddle and Dobrovolny ( 1952) described 

sandstone units at the base of Devonian sections at several localities but did not name them. They believed 

that the Sycamore Creek Formation as originally defined by Lausen and Wilson (1925) included sandstones 

of both Devonian and Cambrian age. 
INTRODUCTION 15 

The present investigation indicates that basal sandstone units of Devonian age are obviously widely distributed from the type locality of the Sycamore Creek 

Sandstone southeastward for at least 80 miles as far 

as the upper Salt River area, but unfortunately the 

name is preoccupied by the Sycamore Limestone of 

Taff ( 1903) of Mississippian age in Oklahoma. The 

formation is here redefined and redescribed as Beckers 

Butte ].1ember of the Martin Formation. 

JEROME FORMATION AND ISLAND MESA BEDS 

The name Jerome Formation was proposed by Stoyanow (1930) for rocks of Late Devonian age at 

Jeromt:,. Details were given later hy Stoyanow (1936, 

p. 495), who described a section of 505 feet of limestone 

and some shale that he subdivided into 20 units and that 

rests on Tapeats Sandstone of Cambrian age. According to Stoyanow, the lower third of the section is characterized by "lithographic limestone"; the upper twothirds is described as "limestones" that, however, are 

more varied and are partly arenaceous, partly fossiliferous, and interbedded with some shale. 

Stoyanow pointed out that rocks typical of the J erome Formation could be traced southeastward from 

the type area as far as t.he headwaters of the East Verde 

River, where he recognized a sandy unit at the base of 

the formation-the "Sycamore sandstone member," 

which is discussed in foregoing paragraphs. North of 

J erom13, Stoyanow reported increasing sandiness in the 

upper part of the Jerome Formation and proposed the 

name "Island Mesa beds" for this supposedly sandy 

facies. 

In 1942, Stoyanow traced the Jerome Formation 

southeastward as far as the headwaters of Tonto Crook, 

Tonto Natural Bridge, and the Payson area, where he 

also rt:~ognized the "Island Mesa beds," but he did not 

again refer to the Sycamore Sandstone Member. He 

mentioned that "coral reefs" occurred in several places 

in the higher parts of the Jerome Formation. 

Both "Jerome formation" and "Island Mesa beds" are 

listed in the Devonian correlation chart published by 

the Geologieal Society of America (Cooper, 1942) in 

the column for north-central Arizona. The name Jerome Formation was also used by McKee ( 1939), who 

applied it to Devonian rocks along the southern border 

of the Colorado Plateau, and by Gutschick (1943), who 

used it for the Devonian rocks underlying the Redwall 

Limestone in Yavapai County. 

Huddle and Dobrovolny ( 1952) mentioned Stoyanow's use of the names Jerome Formation and Island 

Mesa Beds but did not use these terms. Instead, they 

referred to all Devonian rocks in central Arizona as 

Martin Formation. Also, Anderson and Creasey ( 1958, 

p. 49-51) did not accept Stoyanow's term Jerome Formation and used the name Martin Limestone for these 

rocks. 

Stoyanow did not indicate type localities for either 

the Jerome Formation or the Island Mesa Beds. However, his measured section of the Jerome is probably 

somewhere on the slopes below and on the northeast 

side of Jerome in the south-central part of the Clarkdale quadrangle. The section in this area is described 

in more detail on pages 43 and 44. 

The Island Mesa Beds ( Stoyanow, 1936, p. 500) are 

described as n sandy facies of the upper part of the 

Jerome Formation that is recognizable "12 miles northeast of Jerome and southwest of Island Mesa." The 

name Island Mesa is used on the "Geologic Map of the 

State of Arizona" (Darton, Lausen, and Wilson, 1924) 

for the mountain that is shown on the map of the 

Clarkdale quadrangle as Black Mountain. The type 

locality is not known because no Devonian rocks occur 

anywhere near the area 12 miles northeast of Jerome 

and no Devonian rocks are found on Island Mesa (or 

Black Mountain). When he described a small molluscan fauna from the "Island Mesa beds," Stoyanow 

(1948) gave no further details of the locality. The 

present investigations have shown that this molluscan 

fauna occurs not in arenaceous rocks but in saccharoidal 

dolomite and that the concept of the Island Mesa Beds 

was most probably based on erroneous lithologic identifications. Therefore, the name should not be used. 

LOWER OURAY FORMATION OF STOYANOW (1986) 

Stoyanow ( 1936, p. 489) reported 54 feet of shale 

and limestone overlying the Martin Limestone on Pinal 

Creek north of Globe; he stated that the limestone contains Oamarotoeehia ,en,dliohi (Meek) and two species 

of Orodus. He referred to these beds as the Lower 

Ouray Limestone, which he believed had the same extent as the restricted Ouray Limestone of Colorado of 

J{irk ( 1931). The outcrops referred to by Stoyanow, 

which had previously been described by Stauffer 

(1928b), are on the southwest bank of Pinal Creek, 

3-31j2 miles downstream from the northern edge of 

Globe. (See Peterson, 1954.) In 1953 and again in 

1956, I measured this section and collected fossils from 

all fossiliferous beds but failed to find 0 amarotoechia 

(now Paurorhynchu8) endUch-i. Because P. endlichi is 

a large and characteristic species that would be difficult 

to overlook, the report of its occurrence at Pinal Creek 

is probably erroneous. 

The different nomenclatures used in describing the 

Devonian rocks of central Arizona and the stratigraphic 

nomenclature used in this report are compiled in table 1. 
16 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

TABLE 1.-0omparative table Of stratigraphic nomenclature applied to Devonian 1·ocks in centra-l Arizona 

Stoyanow Stoyanow (1936) Russak of Short and Huddle and Dobrovolny Anderson and Lehner (1958) This paper (1926) (1942) others (1943) (1945, 1952) Creasey (1958) 

I 

Island Upper member Upper unit UnitD 

Mesa Martin (I) ~ --- Upper unit 

beds formation ta Middle member ~ Middle unit ~ Unit C ,0 

~ e ~ 

~ .9 Limestone Crook ~ e 

... Mount formation e 

.g Elden .. 

.g (I) formation 

e . s 0 

~ Lower ta 

..... ~ member 

Sycamore 

Creek 

sandstone 

EASTERN ARIZONA 

In the Clifton-Morenci area near the New Mexico 

State line the Devonian System is represented by the 

Morenci Shale (Lindgren, 1905). This unit is probably an extension of the Percha Shale of New lfexico, 

but its exact correlation with the Devonian formations 

of central Arizona has not yet been established. 

ACKNOWLEDGMENTS 

During the field season in 1953, I was accompanied by 

Harry Burgess and D. V. LeMone, then undergraduate 

students of the New Mexico School of Mines. During 

the 1956 season I was accompanied in the field by R. L. 

Harbour, who measured several stratigraphic sections 

and prepared field descriptions, which have been incorporated in the more detailed section descriptions of this 

report. In 1956 and again in 1957, I benefited greatly 

from field conferences with A. F. Shride and Medora 

Krieger, with whom I visited several critical localities. 

A. F. Shride was also most helpful in discussions of the 

general pre-Devonian geology of the area between the 

Salt River and the Mogollon Rim. Christina Lochman-Balk, of the New Mexico School of Mines, visited 

some localities with me in the upper Salt River area 

and helped to clarify some basal Devonian relationships. 

In paleontological_ studies I received valuable support from Kenji Konishi ( calcispheres and related 

microfossils), W. A. Oliver, Jr., (corals and stromatoporoids), Helen ·Duncan (tabulate corals), P. E. 

Cloud, Jr., (brachiopods), Jean Berdan and I. G. Sohn 

(ostracodes), B. F. Glenister, of Iowa State University 

(conodonts), and J. M. Schopf (plants). Laboratory 

work was done by I. A. Breger (organic content of 

fetid dolomite), J. C. Hathaway (electron microscopy), 

R. F. Gantnier (heavy minerals), J. A. Thomas 

( Ca/Mg ratio determinations, mechanical analyses of 

sandstones, and determinations of insoluble residues of 

carbonate rocks), E. J. Young (mineral identifications), 

Gertrud Teichert (microphotography, fossil photo-

~ e --- ~ 

~ (I) 

.. .9 ~ Light buff- Lithographic .g ~ Aphanitic 

~ .s (I) weathering unit 

~ Unit B e e dolomite 

beds 6 0 unit <ll ~ ~ ~ --- ~ ..... 

Brown beds Lower unit Unit A .s Fetid 

~ dolomite unit 

~ 

Basal Beckers Butte 

sandstone Member 

graphs), John Stacy (drawings), and N. S. Taylor 

(thin sections). To all these persons I express my 

thanks for help received. 

I have, furthermore, benefited greatly from discussions on general aspects of the work with J. L. Wilson, 

Shell Development Co., and with E. D. McKee. 

Finally, I thank the Shell Oil Co. for the release of 

results obtained in 1953 and J. G. Mitchell, American 

Stratigraphic Co., for information on several wells. 

All persons whose professional affiliations are not indicated are or were on the staff of the U.S. Geological 

Survey. 

OUTLINE OF THE DEVONIAN SYSTEM IN CENTRAL ARIZONA AND PROPOSED STRATIGRAPHIC 

NOMENCLATURE 1 

Rocks attributable to the Devonian System in central Arizona range in thickness from a few feet to more 

than 500 feet; in some places no sediments were laid 

down during the Devonian Period. The rocks represent a large variety of types including conglomerate, 

sandstone, siltstone, and shale and a wide range of carbonate rocks from almost pure limestone to high-magnesium dolomite. Also, much impure carbonate rock 

oc.curs that contains varying and in places large quantities of detrital siliceous material. 

These sedimentary rocks range from either Early or, 

more probably, Middle Devonian to early Late Devonian ( lat8 Frasnian) in age. In central Arizona they 

lie on a surface of considerable relief that is underlain by a variety of rocks of Precambrian and locally of 

Cambrian age. They are overlain by the Redwall 

Limestone of Mississippian age. 

The oldest unit of Devonian age is a channel sandstone that consists typically of medium- to coarsegrained sandstone and contains subordinat8 conglomer1 The stratigraphic nomenclature used in this report is the accepted 

usage of the U.S. Geol. Survey. In my opinion, all stratigraphic units 

should be upgraded in rank, thus : the Martin Formation to group, the 

Jerome and Beckers Butte Members to formations, and the "units" of 

the Jerome Member to members. 
OUTLINE OF THE DEVONIAN SYSTEM IN CENTRAL ARIZONA AND PROPOSED STRATIGRAPHIC NOMENCLATURE 17 

atic layers, mainly near its base. Crossbedding is very 

common~ and thickness varies considerably and 

abruptly because much of the unit occurs in channel 

fills. The unit is most typical and best exposed in eastcentral Arizona, and ·the name Beckers Butte Member 

of the Martin Formation is here given to it. 

In nmny places, the Beckers Butte Member is shaly 

near its top and locally contains thin beds of impure 

dolomite. A psilophyte flora has been found in this 

member that is either Early or more probably, Middle 

Devonian in age. The entire Beckers Butte Member, 

therefore, is Early or Middle Devonian in age. 

In the Jerome district of north -central Arizona., the 

Precarnbrian rocks are overlain by coarse-grained 

cross bedded sandstone that most authors ( Stoyanow, 

1936; Huff, 1955; Anderson and Creasey, 1958; Krieger, 1H59) regarded with reservation as an equivalent 

of the Tapeats Sandstone of Cambrian age. However, 

this age assignment is ·now considered to be correct. 

In the Jerome area the rock sequence between the 

Tapeats Sandstone and the Redwall Limestone consists 

entirely of dolomite rock (fig. 3), except for a single 

subordinate sandstone bed. This sequence comprises 

the part of the Paleozoic succession that has in the past 

been variously referred to as the Temple Butte Formation) the Martin Limestone, or the Martin Formation 

and that was named Jerome Formation by Stoyanow 

( 1936). The name Jerome Member of the Martin 

Formation is given here, because the lithology of this 

section is quite different from that of the Martin Limestone at Bisbee, 260 miles to the southeast; however; 

too little is known about the distribution and lithology 

of the Temple Butte Limestone to apply this name with 

confidence so far from the Temple Butte type locality 

in the Grand Canyon area. 

Anderson and Creasey (1958) divided the Martin 

Limestone into four well-defined units. The lower unit 

consists of a fine- to medium-grained laminated dolomite 

that emits a strong fetid odor when struck with a hammer. Next above is the "lithographic unit," which 

consiBts of aphanitic dolomite and scattered shaly partings and varying amounts of detrital quartz and chert. 

In this report, Anderson and Creasey's "lower unit" is 

the fetid dolomite unit of the Jerome Member; their 

"lithographic unit" is the aphanitic dolomite unit of the 

,Jerome. These units of the Jerome Member can be 

traced southeastward over considerable distances into 

east-eentral and south-central Arizona-that is, across 

the entire area discussed in this report. In east-central 

_...t\._rizona both units are typically formed along the East 

Verde River and as far east as Diamond Point. They 

are absent from a northeastward-trending belt along the 

Mogollon Rim, where Devonian sections are generally 

thinner, but they reappear in typical lithology in the 

middle Canyon Creek area and extend uninterruptedly 

to the southeasternmost Devonian outcrops on the Black 

River. Both units are also present at Theodore Roosevelt Lake, and at least the aphanitic dolomite unit has 

been recognized in the Globe and Superior areas. 

Above the "lithographic unit" in the Jerome section, 

Anderson and Creasey distinguished a middle and an 

upper unit. The middle unit is characterized by cona> 

~ 

-~ 

c 

0 

:;:::; 

(.) 

Q) 

(f) 

0 

Q) 

(f) 

ro 

.0 

Q) 

> 

0 

.0 

ro 

Q) 

(.) 

c 

2 

.!!! 

"0 

-~ .r:. 

0. 

ro 

On 

:;:::; 

~ 

en 

500~~--------------.---------------.-~ 

400 

300 

200 ()) 

c 

.8 

<f) 

()) 

E 

:.::::i 

\ 6 

Type section of 

Martin Limestone 

Q) 

c 

.8 

<f) 

()) 

~ u 

E 

E 

0 

0 

0 

2 .E 

0 

0 

"0 

u 

:;:; 

·u 

-ro 

0 

/. 

X 

X 

I 

X 

X 

X 

X 

I 2 X .E 

0 

0 

0 

X 

1 

I 

X 

y 

X 

\ X 

I 

X 

I 

)( 

X 

X 

< X 

I 

X 

\ 

X I . \ 

100 6. (Estimated) X 

Typical section of x X 

Jerome Member X "x 

( 

X 

oL-~---------------L--------------~~ 

0 2.1 10.8 19.6 21.6 

MgO content, in percent of total carbonate 

FIGURE 3.~Mg0 content of rocks of the Martin Limestone at its type 

section (.6.) and of the Jerome Member at its typical section (X). 
18 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

spicuously mottled dolomite. The upper unit is distinguished by a diverse lithology that includes all the rock 

types in the underlying units. 

Mottled dolomite rock also typifies the upper part of 

the Devonian sequence in east-central Arizona. A gradual increase of terrigenous rocks (sandstone, siltstone, 

shale), however, occurs in this direction; areas of undolomitized or little dolomitized limestone exist, and 

considerable interfingering of different kinds of siliceous-detrital and carbonate facies occurs. All the Devonian rocks above the aphanitic dolomite unit, the top 

of which is everywhere well defined, are therefore included in one upper unit of heterogeneous lithology. 

The greatest part of the carbonate component of this 

upper unit of the Jerome Member is similar in lithology 

to rocks of the middle and upper units as defined by 

Anderson and Creasey. Because the fetid dolomite and 

the aphanitic dolomite units in east-central Arizona 

have lithologies identical with those of the corresponding units at Jerome, because most of the carbonate rocks 

of the upper unit resemble those in the upper part of 

the section at Jerome, and because none of these rock 

types are known from the type section of the Martin 

Limestone at Bisbee, the Devonian rocks above the 

Beckers Butte Member in east-central Arizona are here 

referred to the Jerome Member. Because the units in 

the Jerome are partly modified by the occurrence of 

clastic siliceous facies, they are here called the Martin 

Formation rather than the Martin Limestone. 

The Jerome Member in east-central Arizona is in 

places extremely fossiliferous, corals and brachiopods 

being the predominant types of fossil organisms. Certain types of microorganisms ("Umbella," calcipheres) 

are locally abundant. Other fossil groups are generally 

less well represented, such as crinoids (stem parts only) , 

bryozoans, pelecypods, gastropods, ostracodes, and 

others. Stratigraphically important coral associations 

have been determined by W. A. Oliver, Jr. (written 

commun., 1959) to be of Frasnian age. The brachiopods contain elements generally associated with the Independence fauna of Ohio and the Sly Gap fauna of 

New Mexico, both of which are probably Chemung 

equivalents (P. E. Cloud, Jr., written cornmun., 1960). 

A small conodont fauna, identified from one locality 

only, also indicates a late Frasnian age (B. F. Glenister, 

written commun., 1960) . All these critical faunal assemblages were obtained from the uppermost part of the 

upper unit of the Jerome Member; so, this unit in its 

entirety is not younger than late Frasnian in age. 

To preserve continuity with the previous literature, 

the name Martin Formation is applied to the entire sequence formed by the Beckers Butte Member and the 

several units of the Jerome Member. The age of the 

Martin Formation thus defined ranges from Early or 

Middle Devonian to early Late Devonian (late 

Frasnian). 

The exact relations between the Martin Formation of 

central Arizona and the Martin Formation of southeastern Arizona still remain to be established. The upper unit of the Jerome Member can be ·correlated with 

the greater part of the Martin Limestone. However, 

no lithologic equivalents of the fetid and aphanitic dolomite units of the Jerome Member nor of the Beckers 

Butte Member occur in the Martin type section. Detailed correlation of the Devonian sections in central 

and in southeastern Arizona will have to await restudy 

of the type area of the Martin Limestone. From the 

available evidence the Martin Formation as here defined seems to represent a somewhat longer time span 

than the Martin Limestone of the Bisbee area. 

Table 2 presents a summary of the stratigraphy of 

the Devonian System in central Arizona as used in this 

report and the most important data on thickness, lithology, fossil content, and age correlation of individual 

stratigraphic units. Thicknesses of members and units 

measured at different localities have been compiled in 

table 3. 

ROCKS OF THE MARTIN FORMATION 

The following description summa.rizes rocks of the 

Martin Formation; more detailed information is presented in the 47 measured sections (p. 105-109) and is 

graphically summarized in the columnar sections on 

plates 28-31. Measured stratigraphic sections are numbered 1 through 4 7 and are so referred to in the text .. 

In addition to discussions of the general character of 

the rock sequences and their lateral facies distribution, 

unusual and geologically important rock types are described in more detail. Fossil faunas and floras a.re also 

discussed, insofar as they are important as rock constituents. Their age and paleoecology are discussed in 

a separate section (p. 27-29, 55-67). 

As Far as possible all important rock types have been 

illustrated either as hand specimens or as thin sections. 

TERMINOLOGY AND CLASSIFICATION OF CARBONATE 

ROCKS 

Carbonate rocks constitute the bulk of the Devonian 

formations of central Arizona, and the study of their 

microfacies is emphasized in this report. They occur 

in considerable variety and include the full range of 

rock types from pure limestones to pure dolomites. In 

view of the importance and prevalence of these rocks 

in the Devonian System of central Arizona., some remarks on their classification and terminology are desirable. 
Member 

Jerome 

Beckers 

Butte 

Unit 

Upper 

Aphanitic 

dolomite 

Fetid dolomite 

ROCKS OF THE MARTIN FORMATION 

TABLE 2.-Subdivisions of the Martin Formation in central Arizona 

Thickness 

(feet) 

0-385 

0-159 

0-55 

0-166 

Predominant lithology 

Typically fine- to coarse-grained 

mottled dolomite and calcitic dolomite; some aphanitic dolomite; 

limestone subordinate. East of 

Verde River, the unit contains 

varying amounts of sandstone, 

siltstone, and shale; locally, it 

contains more limestone and scattered biostromes. 

Almost entirely aphanitic dolomite; 

the unit contains a few shaly partings; in places, it is sandy. Some 

beds are rich in chert. 

Laminated fine- to medium-grained 

dolomite that emits a fetid odor. 

Medium- to coarse-grained sandstone, poorly sorted, locally con- glomeratic or arkosic; commonly 

it is highly crossbedded; it is com- monly shaly near the top and con- tains scattered impure dolomite 

beds. 

Important fossils 

Stromatoporoids: Amphipora, Actinostroma, Anostylostroma, I diostroma, Gerronostroma, Stictostroma. 

Corals: Disphyllum, Breviphyllum, 

Tabulophyllum, Hexagonaria, Tabellaephyllum, Alveolites, Aulocystis, Aulopora, Striatopora, Syringopora, Thamnopora. 

Brachiopods: Devonoproductus, Rhipidomella, Schizophoria, Cyrtospirifer, Platyrhachella, Tenticospirifer, Atrypa, Spinatrypa, Camarotoechia, Cranaena ( ?) . 

Pelecypods: Congeriomorpha, Tusayana. 

Gastropods: Aglaeoglypta, Arizonella, Arastra. 

Fishes: Hesperaspis, Coccosteus, 

Dinichthys, Pyctodus, Dipterus. 

Conodonts: Polygnathus, Palmatollepis, Hindeodella, Synprioniodina, Spathognathodus. 

Position uncertain: "Umbella," calcispheres. 

Generally unfossiliferous; contains a few calcispheres, brachiopods, and 

ostracodes. 

Unfossiliferous. 

Close to top: Psilophyte flora of 

Hostimella?, Aphyllopteris?, fertile structures, megaspores. 

19 

Age 

Late Frasnian 

(top of unit). 

? 

? 

Early or Middle 

Devonian. 

Like other rocks, limestone and dolomite may be 

classified according to ( 1) chemical composition, ( 2) 

structural and textural features, or ( 3) origin and depositional environment. Three mutually independent 

and ove~rlapping systems of carbonate rock classification rna y thus be devised, but unless the particular set 

of criteria used to classify the rocks is clearly recognized 

and stated, confusion will result. 

bonate, or the mole ratio CaO/MgO. (See Guerrero 

and Kenner, 19·55, and Pettijohn, 1957.) Chilingar 

(1957) recently used the ra:tio of the metallic elements 

Ca and Mg; he classified the carbonate rocks into eight 

groups ranging from calcitic limestone to magnesian 

dolomite. The present report uses the classifieation of 

Guerrero and ICenner, and the roeks are generally 

classified by their MgO content. This method has been 

chosen as best suited to graphic representation of calcitic dolomites and dolomites, which are the predominant rock types studied. Carbonate rocks are therefore 

grouped as follows : 

No complete review of carbonate rock terminology is 

intended because simplicity of terminology is of paramount importance. Recent papers on limestones by 

Bathurst (1958) and by Hadding (1958a, b) illustrate 

that carbonate rocks can be described in simple language and with use of a minimum of special technical 

terms. 

CLASSIFICATIONS BASED ON CHEMICAL COMPOSITION 

Carbonate rocks range in composition from magnesium-free calcium carbonate to dolomite rock that may 

carry an excess of magnesium. The composition of any 

rock in this series may be indicated by giving the ratio 

of calcite to dolomite, the MgO percentage of total car745-100 0--·64-2 

Type Percent MgO 

Limestone________________________________________ 0-1.1 

Magnesian limestone _____________ ----------------- 1. 1- 2. 1 

Dolomitic limestone ______________ ----------------- 2. 1-10. 8 

Calcitic dolomite _________________ ----------------- 10. 8-19. 5 

Dolomite _________________________________________ 19. 5-21. 6 

The tetrahedral diagram of Mather ( 1955) gives a 

sufficiently detailed and aecurate1y descriptive breakdown of carbonate roeks containing an admixture of 

detrital material (sand, silt, and day). 
20 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

TABLE 3.-Thickness, in feet, of Martin Formation and its subdivisions 

[abs, not deposited; ne, not exposed] 

Section 

No. Name 

---

1 Sawmill Road _____________________________________ 

2 Black River _______________________________________ 

3 Flying V Canyon __________________________________ 

4 Salt River Asbestos mine ___________________________ 

5 South of Salt River Bridge __________________________ 

6 Salt River Draw (south) ____________________________ 

7 Salt River Draw (north) ___________________________ 

8 East side, Canyon Creek ___________________________ 

9 Oak Creek Farm Road _____________________________ 

10 Spring Canyon (west) ______________________________ 

11 Spring Canyon (east) ______________________________ 

12 Lost Tank Canyon ________________________________ 

13 Southwest Branch of Lost Tank Canyon _____________ 

14 West bank of Canyon Creek ________________________ 

15 East side of Canyon Creek __________________________ 

16 N aeglin Rim ______________________________________ 

17 Upper Colcord Canyon _____________________________ 

18 2 miles south of Turkey Peak _______________________ 

19 Christopher Mountain Ridge ________________________ 

20 Hunter and Sharp Creeks ___________________________ 

21 Hunter Creek _____________________________________ 

22 Four-tenths mile west of Christopher Ranch __________ 

23 Christopher Creek _________________________________ 

24 Christopher Creek Camping Area ____________________ 

25 Boy Scout Ranch No. !_ ___________________________ 

26 Doubtful Creek ___________________________________ 

27 Tonto and Horton Creeks __________________________ 

28 ]{ohl Ranch _______________________________________ 

29 Thompson Wash __________________________________ 

30 Diamond Point ____________________________________ 

31 Webber Creek _____________________________________ 

32 East Verde River __________________________________ 

33 Upper Sycamore Canyon ___________________________ 

34 Tonto Natural Bridge ______________________________ 

35 Pinal Creek _______________________________________ 

36 Theodore Roosevelt Dam ___________________________ 

37 Windy HilL ______________________________________ 

38 Limestone Hills ____ - ____ - ______________ - __ - _____ - _ 

39 Chasm Creek _____________________________________ 

40 Squaw Peak mine __________________________________ 

41 Jerome ___________________________________________ 

42 Upper Hull Canyon ________________________________ 

43 Verde River at Sycamore Creek _____________________ 

44 Elden Mountains __________________________________ 

45 South of Iron ]{ing mine _______ -'- __________________ 

46 Sevenmile Creek ___________________________________ 

47 Mormon Tank ____________________________________ 

It is somewhat unfortunate and has long been recognized as a terminological inconvenience that both a 

mineral and a rock carry the name dolomite. The fact 

that rock called dolomite only rarely consists entirely 

of the mineral dolomite is apt to lead to confusion. A 

proposal to abandon the term as applied to rocks was 

first made by Grabau (1913, p. 298), who suggested 

dolomith or dolomyte for dolomite rock, but he did not 

use either of these terms himself. Shrock ( 1948a) proposed the term "dolostone," but this too has found little 

Jerome Member 

Total Beckers 

Martin Butte 

Formation Member Fetid Aphanitic Fetid and Upper Total dolomite dolomite aphanitic unit 

unit unit units 

159 ne 159 ne ne ne 159 271~ 18 253~ 34 95 129 124~ 

359 15 344 29 113 142 202 

280 8 272 24 95 119 153 

122+ 119 3+ 3+ ne 3+ ne 480 42 438 16~ 130 146~ 291~ 

140+ ne 140+ ne ne ne 140+ 

516 146 370 15 116 131 239 

142 abs 142 abs abs abs 142 

36 abs 36 abs abs abs 36 

75 abs 75 abs abs abs 75 

386 84 302 19 71 90 212 

303 ne 303 ne 5~ 75~ 227~ 

143 abs 143 abs abs abs 143 

133 abs 133 abs abs abs 133 

197 abs 197 abs 25 25 172 

222 abs 222 abs 63 63 159 

199 abs 199 abs 24 24 175 

144 abs 144 abs abs abs 144 

174 abs 174 abs abs abs 174 

117 abs 117 abs abs abs 117 

110 abs 110 abs abs abs 110 

100(?) abs 100(?) abs abs abs 100(?) 0-15 abs 0-15 abs abs ans 0-15 

39+ abs 39+ abs abs abs 39+ 

175 abs 175 abs abs abs 175 

321 abs 321 abs 55 55 266 

292 abs 292 abs 15 15 277 

282+ abs 282+ abs 100+ 100+ 182 

448 90 358 20 158 178 180 

437 114 323 18~ 35~ 54 269 

437 68 369 19 150 169 200 

467 65 402 8 109 117 285 

389 abs 389 abs 94~ 94~ 294~ 

262 ne 262 ne 59 59 203 

486 101 385 20 102 122 263 

382+ ne 382+ ne 78+ 78+ 304 

480 86 394 21 155 176 218 

305+ 40+ 265 40 135 175 90 

63+ 41 22+ 14 8+ 22+ ne 450 abs 450 21 122 143 307 

530 abs 530 55 159 214 316 

367+ ne 367+ ne 58+ 58+ 309 

181 ne 181 ne ne ne 181 

135 abs 135 abs abs abs 135 

258 6 252 32~ 76~ 109 143 

373+ 100+ 273+ abs 163 163 110+ 

acceptance; dolomite as a rock term continues to be used 

by most authors. Vatan ( 1958) protested against dolostone on etymological grounds. 2 

2 When naming a rock which is composed predominantly or entirely 

of one mineral, it bas long been customary to form the rock name by 

addition of the suffix "ite" to the mineral name, as in quartzite, proxenite, and others. By analogy, the term "dolomitite" would seem a 

logical choice for the rock, dolomite to be retained for the mineral. However, tradition will probably effectively prevent replacement of the 

term "dolomite" for rocks, and the term is used for the rock in this 

report. Where an ambiguity is likely, the term "dolomite rock" is used. 
ROCKS OF THE MARTIN FORMATION 21 

CLASSIFICATION BASED ON STRUCTURAL AND 

TEXTURAL FEATURES 

Widely diverging systems of classifying carbonate 

rocks on the basis of structural and textural features 

have been proposed, but most of these systems classify 

limestone rather than dolomite, which is predominant 

among the Devonian rocks of central Arizona. Among 

recent classifications based on textural features, those 

by Bramkamp and Powers (1958) and by Folk (19·59) 

seem to be most generally applicable. The classification 

of Bramkamp and Powers is based mainly on grain size 

and includes both limestone and dolomite. Folk's classification is based on separation of three fundamental 

constituents: major individual particles-called allochems-matrix, and cement. Different combinations of 

these constituents enabled Folk to distinguish 11 types 

of limestone. This scheme gains complexity from the 

introduction of many new rock terms. Inasmuch as a 

co.mpletely graded series of rocks can always be assembled between any two sedimentary rock types, multiplication of terms for sedimentary rocks offers no ideal 

solution for their classification and description. Also, 

Folk's classification is not applicable to dolomites, and 

I therefore prefer the scheme offered by Bramkamp 

and Powers, which has the added advantage of including mixed sandy-carbonate rocks as well as dolomites 

and dolomitic limestones. 

The classification of Bramkamp and Powers uses wellknown familiar rock terms, which are more precisely defined with the help of modifying adjective-for example, "sandy partially recrystallized calcarenite." 

Such a system is sufficiently flexible to allow its extension to other rock types not covered by the original 

classification--for example, the ultra fine grained 

aphanitic dolomites that are widespread in central 

Arizona. 

CLASSIFICATIONS BASED ON ORIGIN AND 

ENVIRONMENT 

Because the history of a rock can be determined 

through study of its physical and chemical properties, 

an element of subjectivity is inherent in any genetic 

and environmental classification of sedimentary rocks. 

In such a classification, a census is first made of all possible environments and modes of origin; a suitable number of rock categories is set up, and rock types are 

attributed to them, according to the judgment of the 

observer. The prototype of this kind of classification 

is that offered by Grabau ( 1913), in which he set up such 

major categories as pyrogenic, atmogenic, hydrogenic, 

and biogenic rocks. To Grabau we owe the terms 

"calcirudite," "calcarenite," "calcilutite," which are now 

widely used and generally understood. 

Pettijohn (1957) made a basic distinction between 

autochthonous and allochthonous limestones. The 

autochthonous include reef and biohermal limestones 

and biostromes; the allochthonous include calcarenites, 

calcirudites, and calcilutites, whose particles have probably been transported. Such a classification, though 

desirable and necessary, must remain flexible, and it is 

subject to changing interpretations. Beales ( 1958) believed that some calcarenites are not transported but 

were precipitated in place. This conclusion is almost 

certainly true for some calcilutites, as is indicated on 

page 41. Thus, calcarenites as well as calcilutites 

may be either autochthonous or allochthonous. In 

dealing with environmental and genetic classifications, 

we must remember that the units of classification are derived secondary concepts based on generalizations and 

that exceptions to every rule (or generalization) always 

occur. 

In the following discussion, rock terms implying environmental and genetic classification are used with caution and only where possibility of misjudgment is remote. Thus, a microcrystalline limestone is referred 

to as such and not as calcilutite, unless its detrital origin 

is certain. 

BECKERS BUTTE MEMBER 

The Beckers Butte Member of the Martin Formation 

is here named for Beckers Butte, where the oldest 

Devonian rocks in central Arizona are exposed. Beckers Butte is a prominent peak, about 4,800 feet high, 

capped by Redwall Limestone, and situated in the triangle formed between the Salt River and Flying V 

Canyon (pl. 32). The sandstone is of extremely variable thickness, rests on an irregular surface of Precambrian rocks, and is overlain by the Jerome Member 

of the Martin. Below the Redwall, a complete section 

of Devonian rocks occurs that is similar to that which 

can be more easily observed across from Beckers Butte 

on the west side of Flying V Canyon, especially in the 

road cuts of U.S. Highway 60 (bottom of section 3). 

These outcrops are here designated as the type section 

of the Beckers Butte Member, because this is the only 

place where fossils have so far been found in this member (fig. 4). 

The lithology of the rocks here included in the 

Beckers Butte Member and the fossils from this locality 

have been described by Teichert and Schopf (1958, p. 

210-211). The Beckers Butte Member as now defined 

consists of subunits 1-'6, which were called units in that 

paper (p. 209, fig. 1B) and was described as follows: 

A:bove a slightly irregular surface of weathered diabase lies 

a sandstone unit (1) which is 5 feet 6 inches to 6 feet thick. 

The lowermost 6 inches of this unit consist of very coarsegrained, poorly sorted, mottled gray and brown sandstone, with 

quartz and quartzite pebbles up to 6 mm in diameter. These 
22 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

pebbles are generally subrounded to rounded and are embedded 

in a matrix consisting of subangular to subrounded quartz 

grains. Upward, the rock ·becomes increasingly finer-grained 

and better sorted, with a few layers of coarser material in the 

lowermost 2 feet. This finer-grained sandstone is brownish 

gray, indistinctly laminated, with occasional indications of 

current bedding. The grains range from silt size to about 0.5 

mm in diameter, and the rock contains as much as 15 percent 

calcareous cement. In the upper half of the unit are a few 

limonitic bands and nodules. The upper surface of this unit 

is undulating, with a relief of as much as 9 inches. This basal 

unit seems to be of very irregular lateral distribution. Within 

100 yards of the point where the base of the Devonian sequence 

intersects the highway level, the basal unit wedges out, and the 

next higher sandstone unit rests on the diabase. 

The next unit (2) is about 3 feet thick and consists of alternations of different kinds of sandstone, predominantly fine to 

medium grained, light gray, and generally distinctly fissile. 

Usually, these rocks are poorly sorted; grains range from silt 

size to about 1 mm, and the larger grains are normally subrounded to well rounded. The silt-size fraction forms a tightly 

packed matrix. There is no calcareous cement. 

Unit number 3 is a bed, 2 feet thick, of massive, hard 

sandstone. This rock is poorly sorted, containing quartz grains 

from silt size to about 1 mm; most .larger grains are well 

rounded, and medium-sized grains are subangular to subrounded. Detrital grains are embedded in a matrix of finegrained dolomite. The surfaces of the larger quartz grains are 

frosted through surficial solution and partial replacement of 

silica by dolomite in the manner recently described by 

Walker ( 1957). Unit 4 includes .5-6 inches of medium-grained, 

friable, and crumbly sandstone and 6--7 inches of dark shale 

with some carbonaceous matter that suggest very poorly preserved plant fragments. ·well-rounded, frosted, detrital quartz 

grains up to 2 mm in diameter are dispersed in the shale. This 

is the lowest bed in the sequence in which indications of fossil 

plant matter were observed. 

A hard layer of fine-grained, light-gray sandstone, 8-12 inches 

thick, forms unit 5, and above it follows a unit ( 6), 2 feet thick, 

FIGURE 4.-Beckers Butte Member resting on weathered Precamb ria n 

diabase. 'l'he massive basal sandstone subunit is 4 feet thick. Thinbedded rocks in upper llart of slope belong to the fetid dolomite unit 

of Jerome Member. On U.S. Highway 60, north side of Salt River 

gorge, near entrance to Flying V Canyon. 

which consists of alternating dark-gray and buff dolomitic shale 

and yellowish-gray, argillaceous dolomite layers. A few 

rounded to subangular sand and silt grains are dispersed in the 

shale. The shale contains coalified plant fragments, scattered 

plant spores, and more finely dispersed carbonaceous matter. 

The main plant bed, from which most of the material examined 

in this study was collected, is in the upper part of this unit 

(pl. 1). The dolomite bed immediately below the main plant 

bed may be taken as typical. It contains 15.5 perce:Qt insoluble 

residue, mostly in the clay fraction. 

The section is given in greater detail here than in 

the more generalized description of section 3 (p. 107). 

Compared with its formation at several other localities, 

the Beckers Butte Member at Flying V Canyon is thin, 

and it has not been studied everywhere in the same 

detail. 

Details of the upper part of the Beckers Butte Member, in particular the psilophyte zone and its stratigraphic relations to the base of the overlying Jerome 

Member, are shown in figure 5. 

In most measured sections the thickness of the Beckers Butte Member ranges from 8 to 146 feet; a greater 

thickness is known at Aztec Peak in the Sierra Ancha, 

where A. F. Shride (oral commun. 1960) measured 

more than 200 feet of Beckers Butte Member. These 

variations in thickness result from deposition of the 

member on an irregular Precambrian surface, which 

is described in detail by Shride (oral commun. 1960'). 

At the type locality, the Beckers Butte Member rests 

on an almost plane surface of deeply weathered diabase 

(Shride, McKee, and Harshbarger, 1952, p. 139) (fig. 

4). More commonly, however, the Beckers Butte rests 

on an irregular surface, and its thickness changes 

abruptly within short distances. Thus, at measured 

section 4 (Salt River) the sandstone is only 8 feet thick, 

but within a few hundred feet of this locality, it is 

30-40 feet thick. 

Typically, the Beckers Butte Member consists predominantly of poorly sorted quartz grains that range 

in size from fine to coarse (fig. 6; pl. 1, figs. 1 and 2). 

In this respect it differs from most sandstone subunits 

of the Jerome Member, which are generally well sorted 

(pl. 24). Feldspar and chert also are locally minor 

constituents. The grains are generally poorly rounded, 

and most are angular to subangular. 

Most rocks of the Beckers Butte Member are at least 

slightly calcareous, and some have considerable amounts 

of calcareous or somewhat dolomitic cement (pl. 1, fig. 

3). Carbonate content is generally lower in sandstones 

in channel fills than in those outside the channels, where 

sedimentation occurred only after the channels had been 

filled. Thus, in section 8 (Canyon Creek), where the 

Beckers Butte Member is 146 feet thick, carbonate content is 0.8-1.3 percent, and in section 5 (south of Salt 

River), where the thickness is 122+ feet, carbonate con-
ROCKS OF THE MARTIN FORMATION 23 

Q; 

.0 

E 

<Ll 

~ 

<Ll 

E 

0 

Q; 

--, 

Aphanitic dolomite unit 

Fetid dolomite unit 

Psilophyte zone 

Beckers Butte Member 

FIGURE 5.-Contact of Beckers Butte Member and Jerome Member on U.S. Highway 60 at mouth of Flying V Canyon. 

tent increases from 1.3 percent at the bottom to 6.8 percent at the top of the section. On the other hand, in 

section 2 (Black River), where the Beckers Butte is 

only 18 feet thick, carbonate content ranges from 6.5 

to 40.8 percent. This trend seems to be general. (See 

also fig. 6.) 

Conglomeratic beds are significantly scarce in the 

Beckers Butte Member. Even basal conglomerates, 

where present, are generally not more than a few inches 

thick, and the pebbles are generally not mor.e than a 

few inches in diameter. The predominant rock type 

among the pe:bbles is quartzite or an admixture of local 

rock types where the Beckers Butte Member rests on 

Precambrian rocks other than the Mazatzal, Dripping 

Spring, or Troy Quartzites. 

Crossbedding is very common in the Beckers Butte 

Member, especially in the channel fills. It is less conspicuous or absent in the upper part of the member or 

where the member is thin. 

The Beckers Butte Member has a wide distribution 

within the area covered by this report. Care must be 

exercised, however, not to confuse it with basal or marginal sandy facies of the three units of the Jerome Member or with the lithologically somewhat similar Troy 

Quartzite of Precambrian age, which it overlies in many 

places. The Beckers Butte Member is easily recognizable and definable where it is overlain by a complete section of the Jerome Member, beginning with the fetid 

dolomite unit. This stratigraphic combination can be 

traced from the Black River (section 2) in the southeast along the walls of the Salt River Canyon and northward into Salt River Draw (section 6) and Canyon 

Creek (section 8) as far as Lost Tank Canyon (section 

12). Excellent exposures occur in the upper part of 

the long cliff that extends along the east side of Canyon 

Creek from near its junction with the Salt River and 

then north ward as far as near Cliff House Canyon. In 

these cliffs the Beckers Butte Member rests on various 

members of Troy Quartzite and maintains a fairly uniform thickness of about 150 feet. The outcrops in this 

cliff seem to represent a longitudinal cut along one of 

the major channels that form a characteristic feature 

of the Beckers Butte. 

Farther to the northwest the typical lithology of the 

Beckers Butte Member is found as far as the East Verde 

River area (section 32, East Verde River, and section 

38, Limestone Hills). Figure 7 shows the exposures on 

the East Verde River, where the Beckers Butte is 68 
24 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

Percent 

1.9 

Percent 

47 .4 1.5 

Percent 

5 

42.1 5.4 

37.6 1.9 4.3 

2.9 1.0 6.9 

pgcmfvsc pgcmfvsc 

A B c FIGURE 6.--Graln-size distrtbutlon of: A, Tapeats Sandstone, section 

42 (Jerome) ; B, Beckers Butte Member, section 39 (Chasm Creek) ; 

and 0, Beckers Butte Member, section 5 (south of Salt River Bridge, 

east of U.S. Highway 60). Letter symbols: p, pebbles; g, granules; 

c, coarse; m, medium; f, fine; v, very fine; s, silt; c, clay. Figures: 

on left of histograms B and G indicate subunit of measured s..ction 

(samples In undescribed section 42 were taken at irregular intervals) ; 

figures on right Indicate percentages of HCl solubles (matrix Is mostly 

carbonate). 

feet thick, rests on granite, and is overlain by the fetid 

dolomite unit of the Jerome Member. 

Channel fills equal in thickness to those in Canyon 

Creek occur south of the Salt River and east of U.S. 

Highway 60 (section 5), but probably the best and most 

easily accessible exposure of a channel of Beckers Butte 

Member is on the south shore of Theodore Roosevelt 

Lake, just southeast of the dam (section 36) (fig. 8). 

The Paleozoic section in this general area was first 

studied in some detail by Ransome (1916, p. 150-152). 

Later contributions were made by Hinds ( 1936, p. 33) 

and by Huddle and Dobrovolny (1952, p. 105-106). 

Because of the general lithologic similarity in many 

places of the Beckers Butte Member and the Troy 

Quartzite on which it rests, the two have not ahvays 

been differentiated. Thus, Ransome (1916, pl. 25) 

showed 160 feet of "Troy sandstone" resting on a 

50-foot basalt flow. Almost certainly some, or perhaps 

even all, of this sandstone is Beckers Butte. Troy 

Quartzite filling channels in the basalt and the Mescal 

Limestone is shown by Hinds ( 1936, p. 33, fig. 50). 

These relations correspond closely to the conditions as 

observed on the south side of the dam, except that it 

is the Beckers Butte, not the Troy, that fills the channel. 

Huddle and Dobrovolny (1952, p. 106) described 15 

feet of "basal sandstone" (Beckers Butte) at Roosevelt that rests on Troy Quartzite of unspecified thickness. This thickness for the Beckers Butte Member 

must have been obtained for beds lying somewhere outside the main channel. 

The base of the Devonian and contact relationships 

between the Beckers Butte Member and Troy Qua;rtzite 

are best studied southeast of the dam (fig. 8), where 

the sandstone channel of the Beckers Butte was first 

recognized by R. L. Harbour and then studied by both 

of us in 1956. This channel is 90 feet deep and steep 

sided. It is filled almost entirely with fine- to coarsegrained poorly sorted generally crossbedded sandstones, 

and contains very little conglomerate and only a few 

layers of shale. (For details, see description of subunits 1-7 of section 36.) 

The channel is cut through the ba:sal member of the 

Troy Quartzite and the upper member of the Mescal 

Limestone (A. F. Shride, oral commun., 1960; equals 

Roosevelt Member of Hinds, 1936, p. 32) into the basalt 

that separates the middle and upper members of the 

Mescal. In the roadcut illustrated in figure 8, the Beckers Butte Member rests on this basalt. Outside the 

channel the Beckers Butte thins abruptly to little more 

than 10 feet. Overlying the Troy Quartzite is 8 feet 

of thin interbedded layers of sandstone and shale. 

FIGURE 7.- Section on northwest side of East Verde River, northeast 

of crossing of Pine-Payson Road. Promlnen t cliffs are the lower part 

of the Beckers Butte Member, which rests on granite (cliffs on right 

side). 'l'he uppermost cliff at the top of the slope is the fetid dolomite unit of the Jerome Member. 
ROCKS OF THE MARTIN FORMATION 25 

FIGURE 8.- StratlfP'aphic section on south side of Theodore R~os lt 

Lake, directly southeast of Theodore Roosevelt Dam, showing channel 

of Beckers Butte Member 90 feet deep, overlain by J erome Member 

and Red wall Limestone. (Section 36 of report Is located here.) 

These layers are in turn overlain by 3 feet of thin interbedded shale and impure dolomite, which probably corresponds to the psilophyte zone on the Salt River (section 3), although no plant remains have as yet been 

found in it. 

Although superficially somewhat similar to the Troy 

<?uar~zite, sandstone of the channel fill is easily distmgmshed by its susceptibility to disaggregation in 

hydrochloric acid, whereas the Troy Quartzite has 

siliceous cement and cannot be so disaggregated. 

Another extensive channel-fill deposit of Beckers 

Butte Member occurs at Aztec Peak (A. F. Shride, oral 

commun., 1960). About 1,100 feet of sandstone was de-

~cribed at this locality by Ransome (1916), but accordmg to Shride about 200 feet of this belon!lS to the 0 

Beckers Butte Member, which fills a channel in Troy 

Quartzite. 

Where the Beckers Butte Member is in contact with 

the Jerome Member, the contact plane everywhere is 

unmistakable, although some gradational features are 

seen. In some places thin layers of fine-grained argillaceous dolomite are intercalated with shaly sandstones 

and shales at the top of the Beckers Butte Member and 

it is in these transitional beds that the psilophyte 'flora 

of the Salt River Canyon occurs. 

A gradational unit at the top of the Beckers Butte 

Member also occurs at Lost Tank Canyon (section 12) 

Chasm Creek (section 39), and at Theodore Roose vel~ Dam (section 36), as has been mentioned on page 24. 

~oreover, ~ similar shale subunit is probably concealed 

m covered mtervals in the sections south of Salt River 

b~idge ( secti~)n 5), Webber Creek (section 31), and 

Limestone H1lls (section 38). In several other localities, however, this subunit is definitely missing, and the 

basal fetid dolomite unit of the Jerome Member has 

a sharp lithological boundary with sandstones of the 

Beckers Butte--for example, in the Salt River section 

( 4) , at East Verde River (section 32) , at Diamond 

Point (section 30), and in the upper Sycamore Canyon 

(section 33). The distribution of the uppermost shale 

and dolomite unit is therefore patchy, either because of 

initially irregular deposition or because of erosion prior 

to the deposition of the Jerome Member. 

The carbonate component at the top of the Beckers 

Butte Member is present at Webber Creek (section 31). 

Here a yellowish-gray very fine grained limestone having a luster texture occurs just below a covered interval of 14.5 feet and probably represents the top of the 

Beckers Butte. Somewhat lower, a calcitic sandy dolomite occurs; it alternates with shale and is similar in 

lithology to the top beds in the Salt River Canyon. 

None of the limestone and dolomite intercalations in 

the top of the Beckers Butte Member have the fetid 

odor that is characteristic of rocks of the fetid dolomite 

unit of the Jerome Member; the boundary between the 

two members is therefore most conveniently placed at 

the base of the first fetid dolomite bed. 

COMPARISON WITH SANDSTONES OF THE JEROME MEMBER 

Recognition and correlation of certain sandstones 

with sandstone in the Becker Butte Member are difficult 

in marginal areas. As successive younger units of the 

Jerome Member overlap the Precambrian basement to 

the northeast, a basal transgressive sandstone facies 

may occur at all stratigraphic levels. (See fig. 40.) 

Some of these transgressive sandstones are lithologically very similar to the rocks of the Beckers Butte 

Member but in some places can be distinguished by 

fossil content. In contrast to the Beckers Butte, they 

are marine littoral deposits and locally contain fish 

remams. 

In the general area of occurrence of the Beckers Butte 

Member, a sandstone can be safely identified as Beckers 

Butte where it is overlain by the basal (fetid dolomite) 

unit of the Jerome Member. Where the fetid dolomite 

unit is absent, sandstone resting on Precambrian rocks 

can be identified only with difficulty as either marginal 

facies of the Beckers Butte or sandstone of the basal 

part of the Jerome Member. Correlations are particularly uncertain in relatively thick seetions, such as sections 27 (Tonto and Horton Creeks) , 28 (Kohl Ranch) , 

and 29 (Thompson Wash) . In these localities basal 

sandstone units are overlain by dolomites of varied lithology. The aphanitic dolomite unit is recognizable only 

in section 27, though its thickness is greatly reduced. 

COMPARISON WITH THE TAPEATS SANDSTONE OF THE 

JEROME AREA 

Correlation problems of a somewhat different kind 

arise when the Beckers Butte Member is tr~ed to the 
26 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

FIGURE 9.-Crossbedded Tapeats Sandstone underlying a typical section 

of Jerome Member 11/o miles northeast of Jerome. (For the exact 

locality, see pl. 32, sections 41 and 42.) 

northwest up the Verde River to the Jerome area. 

In the Mingus Mountain area, the oldest sedimentary 

rocks above the Precambrian are sandstone and siltstone 

beds (fig. 9), which areas much as 100 feet thick according to Anderson and Creasey (1958, p. 48); they are 

overlain in turn by the fetid dolomite unit of the J el'Ome Member (Martin Limestone of authors). As Anderson and Creasey pointed out, Reber (1922), Ransome 

(1932), Stoyanow (1936), and McKee (1951) believed 

that these sandstones and siltstones are Middle Cambrian in age and are equivalent to the Tapeats Sandstone of the Grand Canyon, whereas Fearing (1926) 

and MeN air ( 1951) included them in the basal part of 

the Martin Limestone of Devonian age (Jerome Formation of Stoyanow). Krieger ( 1959) reported that fossiliferous Tapeats Sandstone can be traced from the 

Grand Canyon south ward as far as Walnut Creek in the 

Juniper Mesa. Lithologically similar but unfossiliferous sandstones are "nearly continuous" between Walnut Creek and Jerome, and Krieger therefore supported 

a Cambrian age for the basal sandstones in the Jerome 

section. 

The arguments in favor of a Cambrian as well as of a 

Devonian age have been well discussed by Anderson and 

Creasey (1958, p. 48-50), who slightly favored t he 

Cambrian. 

Fortunately, correlation with the Tapeats was confirmed through discovery of Corophioides-type, Ushaped vertical burrows in the basal sandstone on the 

east side of Mingus Mountain near Allen Spring. Burrows of the same type are common in Tapeats Sandstone at the Juniper Mesa, in the Grand Canyon, and 

elsewhere, where they occur in immense numbers in 

several sandstone beds. Richter (1926, p. 216) has convincingly argued that the animals that made the Corophioides-type burrows must have been relatively sessile, that is, they formed permanent dense populations. 

Richter further reasoned that burrowing animals living under such crowded conditions must have been 

plankton feeders living on a sea floor under normal 

marine conditions, where bottom currents assured a constant supply of fresh food. 

Even though Corophioides-type burrows are known 

from rocks ranging from Cambrian to Triassic in age, 

they assume the importance of index fossils when found 

in a limited area in rocks of similar stratigraphic position and deposited under similar conditions of sedimentation. 

Although the correlation of the basal sandstone at 

Jerome with the Tapeats Sandstone is no longer in 

doubt, it is interesting to compare the basal sandstone 

lithologically with the Beckers Butte. The principal 

difference between the two is their color. The Tapeats 

Sandstone at Jerome is grayish red (5R 4/ 2), whereas 

typical sandstone in the Beckers Butte Member is much 

lighter colored, commonly ranging through the yellowish-red, yellowish-gray, and medium-gray hues. These 

hues correspond to colors generally described as pinkish 

gray, yellowish gray, brownish gray, medium gray, and 

light brown. 

Very dark colors seem to be characteristic of beds 

in the ,Jerome area. Farther south outcrops of basal 

sandstone underlying the carbonates of Devonian age 

are found at Squaw Peak and in Chasm Creek. At 

Squaw Peak (section 40) most of the basal sandstone 

is pinkish gray to yellowish gray (5YR 8/1-5Y 8/1), 

and at Chasm Creek (section 39) yellowish gray is the 

predominating color of the basal sandstone. At Limestone Hills the sandstone ranges in color from light and 

pale brown to pale red and grayish orange pink, and 

almost all colors are in the range of yellowish-red hues. 

Petrographically, the Tapeats Sandstone of J erome 

and the Beckers Butte Member are very much alike. 

The sorting is generally poor, as shown by a comparison 

of histograms of typical samples (fig. 6). The carbonate content of the Tapeats is high and corresponds to 

that of the higher sandstone parts of the Beckers Butte 

lying outside the channels. 

Both at Jerome (section 41) and at Hull Canyon 

(section 42) , the top part of the Ta peats Sandstone of 

Stoyanow (1936) and of Anderson and Creasey (1958) 

is lithologically very similar to the top part of the Beckers Butte Member in some localities. Thus, in the 

Jerome section, 22 feet of coarse grayish-red sandstone 

is overlain by 14 feet of silty shale and argillaceous dolomite. In lower Hull Canyon the basal detrital subunit 

is about 71 feet thick. The lower 41 feet consists of 

coarse crossbedded sandstone; it is overlain by 10 feet 
ROCKS OF THE MARTIN FORMATION 27 

of silty sandstone that in turn is overlain by 20 feet of 

shaly siltstone. No dolomite interbeds were seen in this 

locality, but the siltstone may be dolomitic. 

The presence of silty and shaly beds, which contain 

some impure dolomites,. above the typical Tapeats Sandstone is very reminiscent of the lithology occurring at 

least locally at the top of the Beckers Butte Member, as 

described in the foregoing paragraph; it is therefore 

uncertain whether they should be included in the Tapeats. However, an intensive search yielded no trace of 

plant remains, and these beds have tentatively been included in the Tapen.ts. Clarification of their stratigraphic correbtion, however, should remain a subject 

of further investigation. 

Heavy-mineral suites in the Tapeats Sandstone and 

the Beckers Butte Member are very similar in composition (fig.lO). R. F. Gantnier (written commun., 1958) 

characterized the suites of successive samples from two 

typical localities as follows (samples taken at slightly 

irregular intervals from bottom to top) : 

Tapeats Sandstone (Hull Canyon, section 42) : 

TL-366. Most of the grains are subrounded, but they vary 

from angular to rounded. Much of the ilmenite is fresh; 

all gradations from fresh to completely altered to leucoxene are common. The heavy minerals apparently have 

been reworked, with tourmaline, zircon, staurolite, and 

rutile being more abundant in the early source rocks than 

in the later. 

T57-339. Most of the grains are angular to subangular with 

only a few subrounded and very few well rounded. Ilmenite is nearly completely altered to leucoxene. There 

apparently has been little transportation or reworking 

and no addition of new material. 

'1'57- 340. Most of the grains are subrounded to subangular; 

but several are well rounded, and a few are angular. The 

presence of fresh ilmenite, magnetite, and pyrite with 

gradational grains to completely altered to leucoxene and 

hematite suggest several reworkings with the addition 

of new material. As most of the hematite grains are 

angular, magnetite was probably introduced from the later 

source rock. 

T57-341. The grains are mostly subrounded to subangular, 

except for the leucoxenes, which are usually wellrounded. 

It appears that there has been considerable reworking or 

transporting of the grains, with at least two sources of 

material. The earlier source was probably rich in ilmenite, as indicated by the abundance of leucoxene, with 

clear ziron, and little or no pyrite. The later source of 

additional minerals contained milky zircon, pyrite, and 

little ilmenite. The other minerals appear to have been 

present in approximately equal amounts in all source 

rocks. 

Beckers Butte Member (south of Salt River Bridge, section 5) : 

H56-12. The ilmenite and magnetite grains are subangular 

to subrounded, and the other minerals are subrounded to 

rounded, indicating either cyclic reworking or transportation over a considerable distance. 

H56-13. Most magnetite grains are angular to subangular. 

The zircons are subhedral to euhedral. Other minerals 

are mostly subrounded to well rounded. 

H56-14. Most of the grains are angular to subangular, indicating less transportation or reworking than in the two 

preceding slides. 

H56-15. Most of the grains, except ilmenite and magnetite, 

vary from angular to rounded. Some of the ilmenite and 

all of the magnetite grains are very angular. The material apparently has been partially reworked with the 

introduction of fresh material. 

H56-16. Ilmenite is less common than in preceding slides 

and is nearly completely altered to leucoxene. Approximately 50 percent of the zircons are white and translucent. Most of the grains are subrounded, but some are 

subangular or well rounded. The translucent zircons 

show more evidence of rounding than the clear ones, 

which are mostly subhedral to euhedral. Apparently, 

there have been at least two stages of deposition and reworking and two source areas for minerals. 

The two sandstone suites do not seem to differ materially either in respect to heavy-mineral composition 

or to the general aspect of the heavy-mineral grains. 

In both suites evidence of reworking and addition of 

new material is apparent in most samples, and many 

samples have intermediate stages of less reworking and 

of little or no addition of new material. 

Thus, the heavy minerals in the two sandstones of 

different age came from igneous and metamorphic rocks 

and were either transported directly from their sources 

and deposited or, more generally, had a history of intermediate depositional and erosional stages. Both 

sandstones were ultimately derived from Precambrian 

rocks that include the Troy Quartzite as a possible 

source of the reworked minerals. 

MODE OF DEPOSITION, AGE, AND PALEOGEOGRAPHY 

Outcrops of the Beckers Butte Member over much of 

the area studied are too scattered to allow construction 

of a reliable isopach map. However, the available data 

on distribution and thickness of the Beckers Butte 

have been recorded in plate 27. The distribution of 

the member is apparently restricted to an area southwest 

of a line running approximately northwestward 

through the upper Tonto Creek and upper Canyon 

Creek area. The member probably once extended in 

this direction for some distance, as the small thicknesses 

of the member along the upper Salt River and Black 

River seem to indicate. 

Southwest of this line the Beckers Butte Member 

extended originally for a considerable distance but was 

absent from an area of unknown size near Pine and Pine 

Creek. 

The present northeastern boundary of distribution of 

the Beckers Butte Member most likely coincides closely 

with the boundary of its original distribution. The 

land that was the principal source area of the sandstone 

of the Beckers Butte lay to the northeast. This area 

became more clearly defined and gradually reduced in 

size during Late Devon ian time and is known as the 
28 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

Sample Sample 

T57-341 EXPLANATION 

H56-15 

Ilmenite Muscovite 

H56-14 T57-339 

Magnetite Gold 

H56-13 

c Leucoxene Hematite 

100 percent 

A 

Zircon Pyrite 

Sample Sample 

Staurolite Others 

H56-246 T57-343 

H 56-245 '---'---'--"--'-'---"'-L.L--'-'-'-'-'-->-L-""'--'-' 

0 

B D 

FIGURE 10.-Distr!bution of Important heavy minerals. A, Beckers Butte Member, channel fill, section 5 (south of Salt River, east of U.S. 

Highway 60); B, Beckers Butte(?) Member, section 39 (Chasm Creek); C, Tapents Sandstone, section 42 (Hull Canyon); D, Tapeats 

Sandstone, section 41 (Jerome). 

Defiance uplift or Defiance Positive Area. (See 

McKee, 1943.) 

The northeastern boundary of the area of distribution of the Beckers Butte may have continued generally northwestward from Pine Island to the southwest part of the Jerome district. The Chasm Creek 

and Squaw Peak occurrences (sections 39 and 40) 

would then be within the area of sedimentation of the 

Beckers Butte Member. This suggested correlation, 

however, is highly conjectural at this time, and further 

field investigations west of the Verde River between 

Verde Hot Springs and Jerome are necessary to solve 

the relationships of the basal sandstones in this area. 

Deposition of the Beckers Butte Member was preceded by a period during which the Precambrian surface was eroded to the extent that is now visible in some 

isolated localities such as Theodore Roosevelt Dam and 

Aztec Peak. Avail able figures for thicknesses of the 

Beckers Butte Member suggest that the predepositional 

relief of the Precambrian surface was as much as and 

perhaps slightly exceeded 200 feet, except in some areas 

such as Pine Island, where relief was greater. The 

surface was covered, and its depressions were filled by 

predominantly sandy material that was carried by 

rivers from the northeastern land mass and was augmented, in ever decreasing amount, by material derived 

from erosion of elevations within the sedimentation 

area; the area was entirely covered only in the closing 

stages of the deposition of the Beckers Butte. 

The universal presence of crossbedding, absence of 

marine fossils, and occurrence of the psilophyte flora 

near the tops suggest that the Beckers Butte Member is 
ROCKS OF THE MARTIN FORMATION 29 

mostly of fluviatile origin; it was at first laid down in 

larger river channels, and as these filled up, it spread as 

a comparatively thin sheet over the entire area. Available data, although scattered, are consistent with the 

assumption that at the end of the time of its deposition, 

the Beckers Butte Member had spread as a continuous 

blanket over most of the area southwest of the present 

limits of its distribution and had formed a vast sandy 

and silty plain from which rose Pine Island and perhaps 

a few additional smaller eminences. 

At the conclusion of sandstone deposition, transportation of detrital material diminished in volume, and one 

may picture the sand plain dotted with shallow clay and 

evaporite pans, the presence of which is indicated by 

the spotty occurrence of shale interbedded with impure 

dolomites at the top of the Beckers Butte Member. At 

the same time a psilophyte flora took root near the clay 

pans and perhaps elsewhere. These delicate plants, so 

readily destroyed, have so far been found at only one 

locality, but this flora probably once spread over a wide 

area. 

An observer standing somewhere near the present 

Beckers Butte and looking generally north and north-

>vest might have viewed a panorama remarkably like 

the vivid and imaginative painting of a "Lower 

Devonian landscape" by Burian (in Augusta, 1957, pl. 

5), in which the distant mountains would represent the 

Defiance positive area. 

The age of the psilophyte flora cannot be determined 

more accurately at present than as Early to Middle 

Devonian (Teichert and Schopf, 1958). The apparently conformable contact between the Beckers Butte 

Member and basal unit of the Jerome Member makes 

difficult the assumption that a major time interval occurred between the end of the deposition of one member 

and the beginning of the deposition of the next. The 

entire Beckers Butte Member is therefore more likely 

to be of Middle Devonian age. 

With the exception of the fossil flora, no other fossil 

remains have been discovered in the Beckers Butte 

Member. Reports of fish remains from rocks said to 

belong to this member are somewhat contradictory. 

Stoyanow (1926, p. 313) mentioned the occurrence of 

M ac11opetalichthys in the "basal sandstones" (Sycamore 

Creek Sandstone) along the East Verde River near the 

Pine-Payson Road. In 1936 Stoyanow (1936, p. 499) 

again referred to the fish remains in the basal sandstone, which he then called "Arthrodiran sandstone," 

and reported that the best coll ecting places were in the 

"headwaters of the East Verde River," where "the 

Arthrodiran sandstone rests on the limestone member 20 

of the Jerome formation." Limestone member 20 of 

Stoyanow (1936, p. 497), however, is identical with the 

fetid dolomite unit of the Jerome Member of this report. The fish remains, therefore, probably came out 

of rocks belonging to the aphanitic dolomite unit of the 

Jerome, which is much younger than the Beckers Butte 

Member exposed on the Pine-Payson Road. 

Finally, Stoyanow (1942, pl. 1, fig. 1) published a 

photograph showing basal sandstone resting on granite 

and overlain by Jerome Formation at "East Verde 

Crossing." The sandstone is here marked as Tapeats, 

and yet this place is close to the type locality of the 

"Sycamore Creek Sandstone" of 1926 from which fish 

remains had been reported. 

In conclusion, reports of fish remains in the Beckers 

Butte Member do not seem to have been well substantiated as yet. 

The facies and distribution of the Beckers Butte 

Member are somewhat comparable to those of the Beartooth Butte Formation of Wyoming and Montana, 

which underlies the Jefferson Dolomite in many localities (Sandberg, 1961). However, the Beartooth Butte 

is of Early Devonian age; an unconformity exists between it and the Jefferson Dolomite of Late Devonian 

age, whereas transition from the Beckers Butte to the 

Jerome Member is, at least locally, gradational. 

JEROME MEMBER 

Stoyanow (1936), when proposing the name Jerome 

Formation, failed to designate a type section or to indicate the exact locality to which the section description 

published by him refers. I, therefore, designate section 

41 of the present report as a typical section of the 

Jerome Member of the Martin Formation. It is exposed in a small canyon 1.1 miles northeast of the center 

of Jerome. 

In the following paragraphs, the three units of the 

Jerome Member are described individually, beginning 

with their characteristics at the typical section. The 

description is then extended to rocks in other parts of 

the area, and characteristic rock types are described 

and illustrated for each unit. This description is followed, again separately for each unit, by a discussion 

of the evidence (where available) of age and of mode 

of origin. 

FETID DOLOMITE UNIT 

Everywhere that the entire Jerome Member is present, its basal part consists of fine- to medium-grained 

gray laminated dolomite that generally emits a strong 

fetid odor when struck with a hammer. This unit is 

here called the fetid dolomite unit. Lithologically, it is 

closely related to the overlying aphanitic dolomite unit. 

Both occur generally together-that is, where one is 

present, the other is almost always also present. 

The thickness of the fetid dolomite unit ranges from 

a few feet to 55 feet. The smallest thickness, 8 feet, 

was observed in Upper Sycamore Canyon (section 33); 
30 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

the greatest, 55 feet, in Hull Canyon, west of Jerome 

(section 42) . In the typical section of the Jerome 

Member, its thickness is 21 feet. This is the "lower 

unit" of the Martin Limestone of Anderson and 

Creasey ( 1958). The extraordinarily uniform lithology of this unit over the entire arl:la of investigation 

makes unnecessary the separation of its description in 

the type area from that in other areas. 

The lower boundary of the fetid dolomite unit is 

sharp everywhere (fig. 5) . Although dolomite interbeds occur locally in the top part of the Beckers Butte 

Member, the contact of the member with the fetid 

dolomite unit is well defined because the fetid dolomite 

is free from shale intercalations, has a massive appearance, and is generally cliff forming. Furthermore, the 

dolomite beds at the top of the Beckers Butte have no 

fetid odor. 

The upper boundary of the fetid dolomite unit is less 

well defined than the lower boundary and is doubtful 

a.t some localities because the rocks of the upper part 

of the unit do not everywhere have the characteristic 

odor and because lamination occurs also in some parts 

of the overlying aphanitic dolomite unit. 

The gross lithological features of the fetid dolomite 

unit are shown in figure 5. The rocks are thin- to medium-bedded and in outcrops tend to form one or two 

low cliffs (figs. 4 and 7) . 

The fetid dolomite unit is a very finely crystalline to 

finely crystalline dolomite. Individual crystals are 

mostly hypidiomorphic, but small clusters of idiomorphic rhombohedra are seen in some thin sections. 

The most characteristic feature of the rocks of this 

unit is lamination. On weathered surfaces individual 

layers, each several millimeters thick and of varying 

hardness, can be distinguished. In thin section the rock 

is generally seen to be very thinly (0.1-1.0 mm) laminated. \Vhen well preserved, the laminae can be seen to 

be composed of extremely thin layers of a brown amorphic substance. These layers are generally 10-20 microns thick but may in places be considerably thinner. 

They are irregularly wavy. As seen in thin sections, 

some extend laterally for not more than a centimeter, 

others are much longer, and layers might run together 

or anastomose (pl. 2, fig. 1). The megascopic appearance of lamination probably is due to groupings of these 

very thin laminae. 

The substance forming the laminae may be responsible for the fetid odor given off when the rock is struck 

or crushed. Locally, however, the fetid odor is weak or 

absent, especially in the upper few feet of the unit, 

although such rocks are commonly laminated in the 

same manner as the rest of the rock (fig. 11). 

In spite of thorough dolomitization, original sedimentary structures related to the lamination are localFIGURE 11.- Very fine grained laminated dolomite (millimeter-rhythmite 

of Sander, 1951) from the upper part of the fetid dolomite unit of 

the Jerome Member. The rock has no conspicuous fetid odor. Chasm 

Creek (section 39, unit 6). X 1.4. 

ly preserved. Plate 1, figure 5, shows a preserved 

minute channel less than 1 mm deep that has been 

carved into the top of one layer and that is reflected in a 

downward bending of the succeeding laminae for a 

vertical distance of several millimeters. This rock does 

not emit a fetid odor. Most probably, therefore, the 

original organic substance of the laminae has been 

altered or destroyed. 

Single bands of lighter colored medium-crystalline 

unlaminated saccharoidal dolomite are locally intercalated in the predominantly medium-gray laminated 

rock. In the upper few feet of the unit, brecciated rock 

and minor slump structures are :f.airly common. 

LO< ally the uppermost part of the fetid dolomite unit 

is transitional to the overlying aphanitic dolomite unit. 
ROCKS OF THE MARTIN FORMATION 31 

Aphanitic dolomite may occur in the top of the fetid 

dolomite unit, and intraclastic or brecciated structures 

may be found that are similar to those seen in certain 

beds of the aphanitic dolomite unit (pl. 1, fig. 4). 

Almost everywhere the fetid dolomite unit is rich in 

chert, which occurs mostly as irregularly scattered 

nodules of variable shape and size, in places as much as 

1% feet in diameter. More rarely the nodules occur 

in layers parallel to the bedding. In places they appear 

to have been formed on the sea floor during periods of 

nonsedimentation. Figure 12 shows flattened chert 

nodules occurring between the thin-bedded rocks below 

and the more massive beds above. The surface of the 

bed on which the nodules rest is fiat and not indented, 

but the lowest laminae of the bed irrunediately above 

the nodules are bent around the upper side of the 

nodules. 

Thin sections show that in some rocks formation of 

authigenic silica has taken place on a very small scale. 

Small patches of silica of spherulitic or irregularly 

crystalline texture occur in irregular distribution and 

are locally surrounded by broken and shattered dolomite crystals or may themselves enclose tiny dolomite 

pieces (pl. 4, fig. 5). Some deposition of silica, therefore, has taken place after dolomitization. Whether or 

not this mode of formation accounts for all the chert in 

the fetid dolomite unit has yet to be established. 

Detrital quartz is rather scarce in this unit; so, the 

silica must have been introduced into it from some other 

stratigraphic unit or geological terrane. 

In many places, the upper few feet of the unit consists 

of highly porous dolomite. Rock of this type is generally not well laminated, although some rocks combine 

- - --~ -·- ... ..... :~·,..· .. · 

I 

\ 

FIGU RD 12.- Basal part of fetid dolomite unit of Jerome Member. The 

hammerhead rests on the top bed of the Beckers Butte Member. ::-<ote 

flattened chert nodules at the boundary between the thin·beddcd 

dolomite bel<Yw and the more massive dolomite above. East side of 

Pine-Payson Road north of East Verde River (east side of Sycamore 

Creek). 

distinct lamination with porosity. In some rocks the 

pores, or vugs, are filled with white crystalline calcite. 

Limestone has been found in the fetid dolomite unit 

only on Webber Creek (section 31, subunit 11). This 

occurrence is of particular interest because it provides 

evidence of the primary sedimentary facies of the fetid 

dolomite unit. 

At this locality the fetid dolomite unit is 18% feet 

thick. The lower 15 feet has the typical dolomitic 

lithology of the unit; this rock is very finely crystalline 

and laminated and contains chert nodules and calcite 

vugs. Some bedding planes are slightly rippled, but 

whether these structural features are true ripple marks 

or are caused by slumping cannot be determined. This 

lower part emits only a slightly fetid odor. It is overlain by 2 feet of medium-gray to medium-dark-gray 

limestone that is distinotly laminated and emits a strong 

fetid odor when struck with a hammer. The top of 

the unit consists of 1;~ feet of calcitic dolomite that contains chert. 

Two thin sections cut from the limestone represent 

two slightly different rock variants. One of these (pl. 

2, fig. 2) has a very fine grained to aphanitic groundmass and contains scattered small lenses of finely crystalline calcite. Extremely thin horizontal laminae composed of a dark substance occur in the aphanitic groundmass. These are generally not more than a few microns thick and are spaced from 0.1 to several millimeters apart. In cross section, they are irregularly 

wavy. In addition to the dark laminae, thin bands 

occur, which consist of a more translucent variety of 

calcite that seems to be arranged in minute transverse 

fibers and shows some degree of extinction between 

crossed nicols. These layers, which are about 30- 100 

microns thick, are commonly bent and contorted. 

Their origin is not clear. 

Cross sections of what appear to be roughly hemispherical bodies about 125 microns in diameter that have 

walls about 20 microns thick and are composed of the 

same substance are seen in thin section. These small 

bodies are relatively common, although most of them 

are compressed in varying degrees. The walls have 

the same fibrous structure as the aforementioned transparent layers. The affinities of these objects are at present unknown. These bodies are probably of organic 

origin but do not seem to be calcispheres, although they 

have a fibrous waH structure in common with many of 

the calcispheres. 

A second variety of rock (pl. 3) from the same limestone may be described as "clotted limestone" in the 

sense of Wood ( 1941). This term was proposed for 

Cayeux's "structure grumuleuse" ( Cayeux, 1935, 

p. 271). About one half or slightly more of the rock 

consists of very finely crystalline calcite in which are 
32 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

embedded grains or clots of aphanitic limestone 20--200 

microns in diameter. The smaller grains are angular 

to rounded; the larger ones are generally flat and 

elongated, but some are irregularly rounded. 

The outlines of the aphanitic grains are not sharp, 

although such grains are clearly set off from the calcite 

matrix. The grains are rarely, if ever, in contact with 

each other. Even the smallest grains are separated 

from others by some clear calcite. 

The entire rock contains irregular horizontal dark 

laminae, along which small centers of enrichment of an 

opaque substance are found in places. These laminae 

are as irregular as those in the first rock type described 

but lack the layers of lighter colored material having a 

fibrous texture. Concentrations of tiny lenses of finely 

crystalline calcite which may be as much as 1.5 mm 

high and 3-4 mm long, although most of them are 

shorter, occur along some laminae. 

Apparently, this rock type originated from an aphanitic limestone through a partial recrystallization or 

grain growth (Bathurst, 1959) that resulted in a general 

coarsening of the grain size over very large parts of the 

rock. The clear calcite cannot, in this rock, be interpreted as secondary cement secreted in preexisting 

voids. Such an interpretation requires the assumption 

that, prior to the formation of the cement, the aphanitic 

grains were suspended in air. 

If the rocks of this undolomitized lens may be regarded as representative of the facies of the fetid dolomite unit before dolomitization, the fetid dolomite 

would seem to have been originally an aphanitic or very 

fine grained limestone that was finely laminated by 

thin films of a dark organic substance and contained 

microfossils of hemispherical shape and of unknown 

affinities. 

The original rock in its predolomitization state was 

thus somewhat similar to some rocks of the overlying 

aphanitic dolomite unit. Locally, aphanitic limestones 

also occur in the aphanitic dolomite unit, except that 

in no place are they laminated by organic films. 

The organic material composing the thin dark laminae was investigated from 1960 to the time of this 

report by I. A. Breger of the U.S. Geological Survey, 

who stated (written commun., F ebruary 11, 1960) that 

the organic constituents are all of lower molecular weight, and 

there has been no contribution from land plants. I would 

surmise that deposition was at a considerable distance from 

any shoreline and that the organic matter was derived pri· 

marily from marine organisms. Such substances as proteins 

or carbohydrates as may have been present may have gone 

into solution during acid digestion of the dolomite. Initial 

chromatography, however, indicated the absence of amino acids. 

Breger's emphasis on distance from shoreline is in 

agreement with what we know about the distribution 

of the fetid dolomite unit. The marine organisms from 

which the organic matter in the rock is derived may 

have been algae or diatoms that lived in the mud or 

plankton that was killed off periodically through toxic 

conditions arising in the shallow waters covering the 

mud. 

Whether the fetid odor of the rock is due to its contained organic substance is open to question. The rock 

as such is practically odorless, and the fetid odor is 

noticeable only when the rock is struck with a hammer 

or treated with hydrochloric acid. As already pointed 

out by Go than ( 1940), in many rocks it is not even clear 

if the odoriferous substances are formed at the moment 

when the rock is struck or treated with HCl or if they 

are present in the rock and are liberated by these actions. 

The dolomite rock that characterizes the fetid dolomite unit owes its present appearance to three, and 

locally four or even five, stages of diagenetic processes: 

1. Lithification of the original lime mud and formation 

of aphanitic limestone. 

2. Recrystallization of part of the aphanitic matrix 

through grain growth and formation of lenses of 

fine-grained calcite. 

3. Dolomitization-metasomatic replacement of almost 

all of the rock by very finely and finely crystalline 

dolomite. 

4. Formation of authigenic silica, which may have led 

to the growth of the larger chert nodules. 

5. Local solution and introduction of secondary calcite 

resulting in vuggy porosity; the vugs are either 

void or filled with calcite. 

Stage 1 is very early diagenetic or penecontemporaneous. Stages 2-4 are mesodiagenetic (see discussion 

of diagenesis on p. 78-81) and may have extended over 

a considerable period of time. Stage 5 may be very late 

diagenetic and may be active at the present time. 

The fetid dolomite unit occurs in the Jerome area, 

at Chasm Creek and Squaw Peak, Theodore Roosevelt 

Lake, and Limestone Hills, and farther east from East 

Verde River up Sycamore Creek and across to Diamond 

Point, Lost Tank Canyon, and down Canyon Creek and 

Salt River Draw into the upper Salt River area as far 

as Devonian outcrops can be traced. It is absent from 

a northeastern belt extending from the upper Tonto 

Creek along Christopher Creek and as far southeast as 

the upper part of Canyon Creek. The distribution of 

the unit spans the entire area of investigation ; the unit 

extends over a length of 150 miles and a width of as 

much as 50 miles. Because of the small thickness of 

the unit and its complex diagenetic history and rather 

specialized lithologic features, this widespread distribution is remarkable. Near the northeastern area of nondeposition, the fetid dolomite unit may be represented 
ROCKS OF THE MARTIN FORMATION 33 

by some basal sandstones that are associated with or 

replace the typical rocks of the aphanitic dolomite unit. 

Because the two units cannot be separated where represented by sandy facies- near their wedge edges- the 

stratigraphic relationships within this belt are discussed 

in the section describing the aphanitic dolomite unit 

(p. 47-51), as are some further implications of its origin, including those related to the original environment 

of deposition (p. 81- 84) . 

APHANITIC DOLOMITE UNIT 

TYPE SECTION 

At Jerome and at all other localities where all three 

units of the Jerome Member are typical, the fetid dolomite unit is overlain by a sequence that consists almost 

entirely of aphanitic dolomite. This sequence is the 

lithographic unit of the Martin Limestone of Anderson 

and Creasey (1958), and the name aphanitic dolomite 

unit is used for it in the present report. The thickness 

of the unit ranges from a few feet to 159 feet, but where 

fully exposed its thickness is never less than 35 feet. 

More commonly the thickness is between 100 and 150 

feet. 

In the Jerome section (section 41), the aphanitic dolomite unit is 120 feet thick. It corresponds to unit 19 

of Stoyanow's section (Stoyanow, 1936, p. 497). It is 

made up almost wholly of beds of aphanitic dolomite 

of varying thickness and microscopic texture that have 

a perfect conchoidal fracture. The beds are separated 

by thin interbeds of shale. A sandstone bed, 2 feet thick, 

containing much dolomitic cement occurs 15 feet below 

the top of the unit. This is the "red marker bed" of 

Anderson and Creasey (1958). It is the only sandstone bed in the unit at this locality. Rocks throughout 

the unit are well bedded, and the thicknesses of individual dolomite beds range from a few inches to about 

2 feet. The shale partings between the dolomite beds 

are as much as 2 inches thick but are generally less 

than 1 inch thick. Some subunits of the unit do not 

have shale partings. 

The color of the dolomite ranges from medium gray 

and intermediate red hues to light-gray and yellowishgray and yellow hues. 

The microscopic texture of the dolomite is greatly 

variable. In some beds the rock appears to be perfectly 

homogeneous and isotropic ; in others sedimentary structures can be clearly recognized (pl. 4, fig. 6). Brecciation and intraformational erosion are recognizable in 

some beds on a megascopic scale (fig. 17). The ultrafine textures of aphanitic dolomite have been investigated with the electron microscope (p. 76). 

Little detrital quartz is found in this unit in the 

Jerome area, and where present the grains are very tine 

to fine. The basal part of the unit is 26 feet thick and 

contains small pebble-shaped rounded nodules composed of light-gray chert having a brown limonitic 

rind; the nodules are similar to those observed by Huddle and Dobrovolny ( 1952) in the Salt River area. In 

addition, this part as well as most of the rest of the unit 

contains variable amounts of syngenetic or diagenetic 

chert; most of the chert occurs as irregularly scattered 

lumps in the dolomite, but it locally occurs in small 

nodules arranged along the shale partings between the 

dolomite beds. 

The porosity of these rocks is very low. Small calcite-filled vugs occur in some beds but are generally 

scarce. 

The only fossils seen in thin sections are somewhat indistinct dolomitized forms of calcispheres found in subunits 10 and 14 of section 41. (See pl. 6, fig. 4.) 

In the Jerome section the lower boundary of the 

aphanitic dolomite unit is well defined. An abrupt 

change from the fine- to medium-crystalline saccharoidal dolomite of the fetid dolomite unit to the aphanitic 

dolomite containing brown-rind chert pebbles occurs at 

the base of the aphanitic dolomite unit. The upper 

boundary of the unit is less sharp than the lower and 

could be placed either at the top of subunit 14 or the top 

of subunit 16. Placement is uncertain because, whereas 

these are both aphanitic dolomite, the intervening subunit 15 is very finely crystalline and slightly mottled and 

thus resembles some of the rocks of the overlying upper 

unit. The transition from the aphanitic dolomite unit 

to the upper unit is therefore gradational. 

GENERAL LITHOLOGY OUTSIDE THE JEROME AREA 

The aphanitic dolomite unit consists almost entirely 

of carbonate rocks but includes, in addition, a little 

shale, commonly interbedded with carbonate rocks and, 

locally, some sandstone. 

Almost all carbonate rocks are aphanitic and are 

either pure dolomite or slightly calcitic dolomite. Aphanitic or very fine grained limestone forms very scattered interbeds in predominantly dolomitic sequences. 

Both dolomite and limestone locally contain varying 

amounts of detrital quartz grains as well as chert. 

The most common rock within this unit is aphanitic 

dolomite, which has a megascopic appearance similar 

to lithographic limestone. Such aphanitic dolomite 

breaks typically with a smooth conchoidal surface (fig. 

13). The bedding is everywhere well defined and 

ranges from thin to thick bedded; the thicknesses of individual beds are between 6 inches and 2 feet (figs. 5 

and 14). 

Here and there, individual beds are thinly laminated. 

Such lamination is indicated in some places by color 

variations or may be caused by variations in the texture of the dolomite matrix, by differences in grain size 

within alternating layers (pl. 4, fig. 1), or, more rarely, 

by thin layers of quartz grains of detrital origin that 

alternate with the dolomite layers. 
34 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

Especially in the lower part of the unit, dolomite 

beds are commonly separated by layers of shale as much 

as 2 inches thick. Invertebrate trails are locally found 

in these shales, which proves that the shales represent 

sediments originally deposited as clay and are not residuals from solution of carbonate rock. 

Mud cracks are rather common, both in the dolomite 

and in the shaly interbeds (fig. 15). Dolomite rock 

having mud cracks on bedding planes tends to be thinly 

FIGURE 13.-Aphanitic dolomite having a conchoidal fracture and containing much detrital quartz. Aphanitic dolomite unit, section 12, 

Lost Tank Canyon, subunit 16. X 1.75. 

FIGURE 14.-Fresh outcrop of aphanitic dolomite unit on U.S. Highway 

60, close to mouth of Flying V Canyon. 

laminated (fig. 16). The thickness of the laminae is 

~bout "Yi 6-Ya inch and, in the rock shown in figure 16, 

what appear to be small shrinkage cracks irregularly 

penetrate several laminae. 

The color of the aphanitic rocks in weathered outcrops 

tends to have rather uniformly very light values of 

gray, yellowish ~ed, and yellow. On fresh surfaces there 

is a greater variety of colors ranging from medium 

values of gray and r.ed to high values of red, yellowish 

red, and yellow. Aphanitic dolomite is generally lighter 

colored than aphanitic limestone. Thus, in measured 

section 32, the limestone is in part medium dark gray 

(N 4) and grayish red (5R 4/ 2), whereas such low-value 

colors are rarely seen in dolomite. In many sections 

the stratigraphically hl.gher rocks definitely tend to be 

lighter colored than the rocks below. Thus, in section 

39 the relatively low values N 5 and N 6 characterize the 

lower part of the aphanitic dolomite unit, whereas N 7, 

Y R 7, and Y 7 values are common in the upper part. 

Most aphanitic rock types are quite homogeneous in 

texture, but conspicuously fragmental beds are interspersed. Breccias and microbreccias are, in fact, not 

uncommon in the aphanitic dolomite. These are rocks 

in which angular to subangulrtr clasts of aphanitic dolo-
ROCKS OF THE MARTIN FORMATION 35 

mite are "floating" in a matrix composed of aphanitic 

dolomite having a slightly different color or degree of 

transparency (fig. 17). Typical, megascopically recognizable breccias consist of clasts as much as 15 mm in 

diameter, and only a few exceed this size. They are 

generally rather tightly packed, and the volume of the 

clasts exceeds that of the matrix. 

FIGURE 15.-Mud cracks in aphanitic dolomite near the top of th e 

aphanitic dolomite unit of the .Jerome Member, section 32, East Verde 

River. The rock is finely laminated and is of the type shown in 

figure 16. 

Microbreccias are breccias that are recognized with 

difficulty, or not at all, with the naked eye or with a lowpower magnifying glass; individual clasts range from 

about 1 mm to as little as 0.05 mm in size. 

Subunit 12 of section 39 is typical of the coarsegrained microbreccias in which clasts of aphanitic dolomite are embedded in aphanitic dolomite matrix; the 

ratio between clasts and matrix is about 1: 1. The 

clasts are of two kinds, of which one is slightly darker 

and less transparent. The size of both kinds ranges 

from 0.1 mrn, or perhaps Jess, to as much as 2 mm; the 

average size is about 1 mm. They are angular to 

rounded. The matrix of this rock is primarily 

aphanitic but contains numerous tiny dolomite rhombohedra having a maximum size of 35 microns, although 

most are smaller. Small dolomite crystals are also 

present in the clasts where, however, they are far less 

abundant. This distribution appears clearly in the 

photomicrograph (pl. 4, fig. 3). If the clasts are of 

intraclastic origin-and there is no evidence to the contrary-their formation undoubtedly took place when 

only few dolomite crystals had formed in the original 

dolomitic mud. After the formation of the clasts, reFIGURE 16.-Thlnly laminated aphanitic dolomite near the top of the aphanitic dolomite unit of the .J erome Member, section 32, East Verde 

River. 
36 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

FIGURE 17.-Aphanitic dolomite having an intrastratal erosion surface. 

Small fragments of the lower, darker rock have been torn loose and 

become embedded In the upper lighter rock. Both types of rock also 

contain clasts having other derivations. Aphanitic dolomite unit, 

section 4, Salt River, subunit 7. X 1.5. 

crystallization of the dolomitic matrix continued but 

did not affect the clasts. 

A somewhat different rock is that of subunit 3 in section 37 (Windy Hill) (pl. 4, fig. 4). This consists of 

an aphanitic dolomite matrix containing abundant 

aphanitic dolomite clasts that rarely exceed 1 mm in 

s1ze. There are swarms of clasts that are as small as 

50 microns and yet a.re definitely recognizable. Here, 

too, the clasts are less transparent than the matrix, as 

they are more finely aphanitic. Crystal size of the 

matrix appears to be about 5-7 microns; that of the 

clasts is less than 3 microns. ·wnether the difference 

in crystallinity of clasts and matrix is due to the external origin of the clasts or to the recrystallization (or 

grain growth) of the matrix is difficult to determine 

in this particular subunit. 

Another type of intraclastic breccia is exemplified 

by subunit 13 of section 38 (Limestone Hills) (pl. 5, 

fig. 4). In addition to scattered, small very finely 

aphanitic clasts, which generally range from 1 mm to 

about 20 microns in size, well-defined oblong to rounded 

areas that contain finely crystalline dolomite occur. 

Several of these are seen in the upper part and just 

right of center of the section illustrated in plate 5, figure 

4. Their shape and distribution in the rock suggest a 

clastic origin. In the same thin section, one of the 

finely aphanitic clasts has a core composed of finely 

crystalline dolomite. Therefore, the finely crystalline 

dolomite bodies are possibly recrystallized aphanitic 

dolomite clasts, although the nature of the process of 

selective crystallization that formed them remains obscure. Another type of microbreccia is illustrated by 

subunit 20 of section 3 (pl. 4, fig. 6). In this rock the 

sediment apparently was broken but almost no transportation or redistribution of fragments occurred; 

fractures and other open spaces were filled with finely 

crystalline dolomite. 

Grain growth, resulting in the recrystallization of 

cryptocrystalline dolomite into coarser aggregates, is 

relatively common in aphanitic dolomite. The rock 

shown in plate 7, figure 1 is a dolomite that contains 

much detrital quartz. Much of the aphanitic matrix 

(shown on the right-hand side of the photograph) has 

been converted into coarser-grained dolomite, and almost all quartz grains are surrounded by thin rims 

of very fine grained dolomite, which contrasts with the 

darker aphanitic matrix. The rims were also observed 

in some rocks of the upper unit of the Jerome Member 

and are discussed on page 50. 

Another type of breccia is one that has been infiltrated by silica as, for example, the rock of subunit 9 of 

section 39 (Chasm Creek) . This rock is mostly an agglomeration of angular to subangular pieces of aphanitic dolomite as much as 2 mm in size. In between these 

particles, three different substances may be present, as 

is shown in figure 2 of plate 4 : ( 1) aphanitic dolomite 

matrix, shown in lower right corner; (2) areas of crystalline dolomite, such as the large area in the upper 

left of the picture and smaller areas near the center; 

and ( 3) microcrystalline silica, which fills narrow 

spaces betwen clasts, shown to the left and right of 

center, and fills larger areas such as the somewhat circular one in the right center. In another part of the 

same thin section, the almost black and the dark-gray 

matter are aphanitic dolomite, the white parts are microcrystalline silica, and the turbid very finely granulated 

parts are very finely crystalline dolomite. The silica 

and the finely crystalline dolomite are rather intimately 

intermixed. 

Evidence of what appears to be dedolomitization is 

seen in such rocks as subunit 3 of section 37 (Windy 
ROCKS OF THE MARTIN FORMATION 37 

Hill) (pl. 5, fig. 3). _The rook is a. rather uniform extremely finely aphanitic dolomite showing traces of 

sedimentary lamination. Scattered through it are very 

small and irregularly shaped patches of crystalline calcite, which are generally not more than 1;4-1;2 mm in 

size. Their distribution pattern in the rock does not 

suggest any relation to primary sedimentary features; 

nor can it be assumed that they are secondary fillings of 

primary voids. They probably represent calcite replacements of dolomite matrix. 

The aphanitic dolomite unit includes a few nonaphanitic rocks, which may be very fine grained to fine 

grained. An example is subunit 10 of section 33 (Upper 

Sycamore Canyon) (pl. 5, fig. 5) . An interesting feature of this rock is the presence of small vugs, 1-2 mm 

in diameter, that are each filled with a single crystal of 

calcite. The vugs are surrounded by a ring of dolomite 

crystals noticeably larger than the average crystals of 

the rock. These crystals obviously had room to grow 

into a small void before the calcite was deposited, and 

this occurrence of calcite, therefore, contrasts with that 

of calcite formed under dedolomitization conditions. 

Vuggy porosity is not very common in the rocks of 

the aphanitic dolomite unit, which typically lacks any 

kind of porosity, even when seen under an electron microscope. Not uncomnwnly, where present, vugs are 

filled with crystalline dolomite rather than with calcite. 

The nature of aphanitic dolomite is described on 

pages 40 and 41 as part of a broader discussion of the 

nature of aphanitic carbonate rocks. 

DISTRIBUTION 

The distribution of the aphanitic dolomite unit coincides largely with that of the fetid dolomite unit (see 

pl. 27) ; that is, wherever the base of the aphanitic dolomite unit is exposed, it is underlain by the fetid dolomite 

unit in almost all places. l{nown exceptions are in the 

area of the upper Tonto Creek (sections 27 and 28), 

where the aphanitic dolomite unit is present, represented partly hy a basal sandy facies, and where the 

fetid dolomite unit is missing. Possibly, however, the 

basal sandstones here in part represent the fetid dolomite unit. The aphanitic dolomite unit, having a more 

or less typical lithology, can be traced from the Jerome 

area southeastward to Chasm Creek (section 39), Limestone Hills (section 38), the Theodore Roosevelt Lake 

(sections 36, 37), the Globe area (section 35), and the 

upper Canyon Creek (sections 8, 14, 15) and Salt River 

districts (sections 4-7). 

In the upper Tonto Creek area, certain basal sandstones that may or may not be associated with aphanitic 

dolomites are interpreted as marginal facies of the 

aphanitic dolomite unit. Thus, at Thompson Wash 

(section 29) the basal part of the Jerome Member consists of about 100 feet of sandstone, includi~g very 

cross bedded strata containing abundant fish remains; 

the strata are here regarded as marginal siliceous-detrital facies of the aphanitic dolomite unit. Both at Kohl 

Ranch (section 28) and at the junction of Tonto and 

Horton Creeks (section 27), basal sandstones occur, 

overlain by thin ( 4 feet and 15 feet, respectively) layers 

of aphanitic dolomite. 

The aphanitic dolomite unit is absent from the entire 

area in which the fetid dolomite unit is missing-that is, 

east of the upper Tonto Creek along a belt extending 

south of the Mogollon Rim and as far as the uppermost 

part of Canyon Creek. 

OCCURRENCE OF LIMESTONE 

Limestone that may be more or less dolomitic occurs 

in some beds a few feet thick at Dia.mond Point (section 

30) and Webber Creek (section 31). The rock is aphanitic and is indistinguishable under the petrographic 

microscope from some of the aphanitic dolomite described in the foregoing paragraphs. It has a faintly 

"pelletal" or clotty texture and locally contains calcispheres and some extremely fine shell fragments, probably of very thin-shelled ostracodes; the rock is therefore similar to the aphanitic dolomite shown in figure 

3 of plate 6. 

Some limestone has undergone extensive recrystallization, as, for example, has the rock shown in figure 1 

of plate 5. This rock is a rather pure aphanitic limestone that contains little siliceous-detrital material and 

has a primary intraclastic texture in which the clasts are 

mostly well rounded. Much of the matrix has been recrystallized, but signs of grain growth are observed in 

most of the clasts. 

A rieh ostracode concentration is known from subunit 

22 of section 32 (East Verde River) (pl. 6, fig. 2). 

This is a mixed assemblage of single detached valves 

and of entire shells in which both valves are in the 

original position. A peculiar laek of orientation marks 

the position of the various shells and shell fragments, 

although the convex side of most of the single valves 

faces downward. The assemblage gives the impression of having accumulated in very quiet water. 

OCCURRENCE OF SILICA 

Siliea occurs in the aphanitic dolomite unit in several different forms: (1) detrital quartz, (2) chert nodules; and ( 3) authigenic siliea as (a) nodules or layers, (b) spherulitic replacement, and (c) "cloudy" impregnations. These types of occurrence are briefly discussed in the following pages. 
38 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CEN~~RAL ARIZONA 

DETRITAL QUARTZ 

Quartz grains of detrital origin are generally common and in places very abundant. They are rarely 

larger than 1 mm in size and are as small as silt size. 

A clayey component is present in all samples (see pls. 

23 and 24) and in some makes up 100 percent of the 

insoluble residue. 

Quartz-grain assemblages in the dolomites are not 

well sorted. Most grains larger than about 0.2 mm are 

well rounded, and locally they may be tightly packed 

so as to form sandy layers. But these laye~rs a~re rare. 

The larger quartz grains almost invariably have a 

"frosted" surface. Frosted sand grains were noted bv 

Short and others (1943, p. 26) in a sandstone bed i~ 

the aphanitic dolomite unit in the Superior area, and 

these authors concluded that wind action caused the 

frosting. 

. It would be tempting to assume that wind transportation was the cause of the erratic distribution of the sand 

grains in the aphanitic dolomite unit o·ver such a wide 

rurea. However, according to Bagnold (1941 p. 76) 

suspension flow in air of sand grains even as 'smail a~ 0.25 mm seems to be inappreciable, although it is important for very fine sand.3 Larger grains must have 

been transported along the sea floor from the beaches 

of the Defiance uplift, as discussed on page 83. 

~he larger size frosted quartz grains may possibly be 

~erived from la~d dunes, fron1 which they were washed 

mto the sea. Since the land probably contained little 

vegetation at that time, the emerged Defiance uplift 

area could conceivably have been covered with extensive areas of blown sand. However, recent investi-

~ations by Kuenen and Perdok (1961) have cast conSiderable doubt on the validity of the traditional assumption that eolian transportation results in frosting 

of sand grains. 

More likely, however, the frosting is due to surficial 

e~ching and carbonate replacement. This possibility is 

discussed on page 86, as this process has affected 

all carbonate rocks of the Jerome Member. 

OHERT NODULES 

Huddle and Dobrovolny (1952, p. 75) described the 

abundance of small chert nodules having yellow-brown 

3 The results of Bagnold's calculations are in complete agreement with 

observed facts. As is well known, large quantities of dust from th~ 

Sahara are being blown far out into the Atlantic Ocean. The particles 

in this eolian sediment average about 25 microns and range from 5 to 

about 50 microns. Similar size material has been transported over long 

distances elsewhere (Hellman, 1879, 1913; Radczewski, 1939). Free 

( 1911, p. 45) compiled a list of maximum sizes of particles in 45 

~mpl~s of airborne dust. Among these, only one sample, collected by 

L1vers1dge (1902, p. 241), contained particles as large as 1 mm. However, a scrutiny of Liversidge's report reveals lack of data on the circumstances und.e·r which this sample was obtained, other than it came from 

a dustfall on December 15, 1880--22 years before Liversidge studied it. 

rinds in what corresponds to the basal part of the 

aphanitic dolomite unit. They describe the nodules as 

being "about the size and shape of beans, averaging 

about 10 millimeters in length" ~and having dark-gray 

centers. The present investigation has shown that this 

"brown rind" chert zone is uniformly distributed across 

the entire area of investigation and that it is present 

wherever the aphanitic dolomite unit has the typical 

carbonate facies. In most places this zone forms the 

basal unit of the member, but in some sections the lowest 

occurrence of "brown rind" chert is as high as 20 feet 

above the base'-for example, in Chasm Creek (section 

39). In section 4 (Salt River) it occupies the interval 

from 17 to 25 feet in the nearby Flying V Canyon 

section (section 3), from the base to 14 feet. At 

Sevenmile Creek (section 46), where the entire Ma.rtin 

Formation is much attenuated, the same zone is only 

7¥2 feet thick, and its base lies 3 feet above the base 

of the aphanitic dolomite unit; the nodules in this 

locality are very flat. 

In general, the brown rind chert nodules characterize 

the lower 25-30 feet of the aphanitic dolomite unit. 

Their average size is as described by Huddle and Dobrovolny, but nodules as large as 1 inch in diameter have 

been observed. 

The wide distribution of these small nodules, their 

uniform appearance-which is distinct from that of 

other chert aceumulation&-and their restricted occurrence in a narrow stratigraphic interval might suggest 

a detrital sedimentary origin. However, it must be 

pointed out that if these nodules were transported from 

some pre-existing chert deposit, they might be expected 

to be associated, at least locally, with rock pebbles of a 

different kind. Such association, however, does not 

exist. Also, a mechanism by which such pebbles could 

have been distributed so evenly over such a large area 

is difficult to imagine. 

At present, the best guess is that the "pebbles" are 

probably syngenetic in origin, but the problem merits 

further study. 

AUTHIGENIC SILICA 

Chert is present throughout the aphanitic dolomite 

member as nodules, disconnected layers, and irregular 

masses, which may be several feet in diameter. These 

chert bodies show no pattern of distribution, except 

that many are associated with bedding planes, and seem 

to be entirely unfossiliferous. This chert type was not 

studied in detail. The origin of the chert bodies is a 

moot question to which this study has not provided a 

satisfactory answer. Elec.tron micrography might 

eventually help to determine the time relationship between. dolomitization and the formation of chert, but 

such investigation was not undertaken. 
ROCKS OF THE MARTIN FORMATION 39 

Much less commonly, silica occurs as spherulitic replacements, as shown in plate 6, figure 5. The illustrated rock is a very fine grained dolomite that consists 

of anhedral dolomite crystals 20-60 microns in diameter. Scattered throughout the rock are irregular 

blotches of quartz, most of which are distinctly spherulitic. Some of the blotches are rosette shaped; others 

are very irregular and are several millimeters in diameter. Silicification was probably effected by grain-bygrain replacement of dolomite. The smallest silica particles have the shape and size of individual dolomite 

grains, and possibly some dolomite grains in the same 

thin section have only partly been replaced by silica. 

If replacement has occurred in adjacent grains, the 

silica was precipitated in optical continuity. The 

spherulitic texture has been formed only in large 

patches, where dozens or even hundreds of dolomite 

grains were replaced. In contrast to authigenic quartz 

crystals, as described on page 86, the spherulitic silica 

has no impurities or inclusions of dolomite. In some 

places, however, one or a few dolomite grains have 

been left unaltered inside an area that has been completely replaced. 

The sequence of events outlined above is not in agreement with Carozzi's statement (1960, p. 320) that silicification processes require the presence of calcium carbonate and that complete dolomitization apparently 

precludes silicification. However, as early as 1907, 

Strahan and others (1907, p. 11-20) demonstrated that 

in the course of the diagenetic history of Carboniferous 

limestones in England, dolomitization preceded the formation of chert. Later, Storz ( 1931, p. 318, 341, pl. 18, 

fig. 146) described many exmnples of silicified dolomites. 

The occurrence of silicified dolomites is interesting 

perhaps because it demonstrates the possibility of migration of silica-bearing solutions through extremely 

fine grained and non porous carbonate rocks. It further demonstrates the fact that silicification followed 

dolomitization, because silicification begins with the 

replacement of individual dolomite grains. A some .. 

what similar process that has occurred in a very fine 

grained dolomite in the fetid dolomite unit is described 

on pages 30 and 31. 

That this process (silicification of dolomite) is reversible is indicated by the specimen illustrated on plate 

5, figure 2, which shows a relatively large irregular area 

consisting of partly spherulitic and partly irregularly 

fine grained quartz. The quartz is entirely surrounded 

by aphanitic dolomite, which is presumably replaced. 

Irregularly placed around its edge are narrow belts of 

aphanitic dolomite that is somewhat more transparent 

than the original aphanitic rock. The shape and alinement of the belts suggest that they represent areas in 

which the original silica was replaced. Other quartz 

vugs in the same slide also show evidence of redolomitization, although to a lesser extent. 

Correns (1950) discussed the conditions that affect the 

solubility of CaC03 and Si02 and the relationship of the 

solubility to the pH. Within the range of pH values 

to be expected in marine sedimentation areas, slight 

shifts in the pH can change a state from one in which 

calcium carbonate is kept in solution and silica precipitated to one in which silica is in solution and calcium carbonate precipitated. But more recent investigators have cast doubt on some of Correns' conclusions 

(see Walker, 1960), and no similar studies on the silicadolomite relationships are extant. Whereas calcification of silica is relatively common, dolomitization of 

silica is probably much rarer. 

In addition to chert and spherulitic replacement, a 

third type of silica replacement occurs in the form of 

"cloudy" impregnations of the kind referred to on page 

36 in the description of certain autocla.stic rock types 

(pl. 4, fig. 2). No definitive evidence is available that 

indicates that the silica has replaced anything in such 

rocks, although locally intimate intermixtures of cryptocrystalline silica and aphanitic dolomite are found. 

Possibly the silica was here introduced penecontemporaneously, and its precipitation was contemporaneous 

with the origin of the clastic structure. This process has 

been named and described as "Durchkieselung" by Storz 

(1931). 

OCCURRENCE OF CLASTIC ROCKS 

The aphanitic dolomite unit includes subunits of both 

sandstone and shale. The few sandstone beds that occur here and there in the normal stratigraphic sequence 

of aphanitic dolomites are generally very fine grained 

to fine grained and have varying amounts of dolomite 

cement (pl. 5, fig. 6). This rock (subunit 5 of section 

37, Windy Hill) also contains a sprinkling of glauconite grains that are of the same general size as the quartz 

grains but are much better rounded and sometimes broken. The glauconite is the yellowish-green variety that 

Gorbounova (in Strakhov, 1958b, p. 198) supposed to be 

characteristic of silty to argillaceous relatively deepwater environments. Cloud (1955, p. 489), on the other 

hand, concluded that "glauconite provides no intrinsic 

evidence about turbulence of the water in which it was 

formed or came to rest." In the present investigation, 

the derivation of the glauconite, which appears to be an 

uncommon constituent of these sandstones, is not clear. 

It probably was not formed in place under prevailing 

conditions of sedimentation, and glauconite-bearing 

sedimentary rocks fron1 which the glauconite grains 

could have been derived are too far away to be considered as a possible source. 

In the Jerome section (No. 41) a sandstone subunit 

occurs near the top of the aphanitic dolomite unit (the 
40 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

"red marker bed" of Anderson and Creasey, 1958), but 

it is less well sorted (see pl. 23) and contains more dolomitic cement and no glauconite. 

Elsewhere, sandstone beds occur intermittently 

throughout the section. Most are clean, fine grained, 

and well sorted, but less well sorted sandstone also is 

intercalated (pl. 24). 

The siliceous-detrital facies found near the marginal 

wedge belt of the aphanitic limestone unit-particularly 

at sections 16, 17, 27, 28, and 29--comprises a variety of sandstones. Many of these sandstones are very 

poorly sorted and contain angular detrital grains. 

Some tend to be arkosic, and others grade into graywackes. (See descriptions of subunits 3 and 4 of section 27, subunits 1 to 3 of section 28, subunits 1 to 3 of 

section 29, and others in similar stratigraphic position.) 

But because of discontinuity of outcrops, the relationships of these rocks with the carbonate facies of the 

aphanitic dolomite unit are not always clear. 

Shale is a normal constituent of the aphanitic dolomite unit and occurs as interbeds between aphanitic 

dolomite beds, especially in the lower half of the unit. 

The shale beds range in thickness from less than an 

inch to 6 inches but are most commonly about 2 inches 

thick. They are well exposed only in relatively fresh 

quarries and roadcuts, where mudcracks and invertebrate trails are visible locally. Search for spores has 

been unsuccessful. 

FOSSILS 

The aphanitic dolomite unit is generally poorly fossiliferous. The aphanitic dolomites are almost entirely 

unfossiliferous. Ghosts of calcispheres were seen in 

thin sections of rocks from section 3, subunit 8, and 

from section 41, units 10 and 14 (pl. 6, figs. 1 and 4). 

The original textures of the walls of the calcispheres 

have been destroyed through dolomitization. "Umbella" is possibly represented in subunit 10 of section 

32. These and other forms are described separately in 

the section on micropaleontology ( p. 103-105). 

Limestones, dolomitic limestones, and some calcitic 

dolomites are generally rich in calcispheres and ostracodes, as well as in unrecognizable microfossil debris 

(pl. 6, figs. 2 and 3; pl. 15, fig. 5; pl. 20, fig. 1). Apart 

from calcispheres, identifiable fossils however, are 

scarce. Silicified brachiopods., possibly Atrypa, occur 7 

feet above the base of the unit in section 2, but this occurrence is unique. The only identifiable ost~acodes were 

obtained from subunit 22 in section 32, where they are 

abundant and well preserved in very fine grained limestone. Jean Berdan studied this small fauna and reported that the most abundantly represented form belongs to the genus H ypotetragona. 

The marginal sandstone facies at Thompson Wash 

(section 29) contains abundant fragmentary remains of 

bony fish plates, which are preserved as external casts 

in the rock. Although very characteristic of this particular facies, unfortunately they are indeterminable. 

The occurrence of fish remains has been noted by previous authors, but there is doubt about the exact localities and horizons. Stoyanow's ( 1926) reported discovery of arthrodiran plates in the basal sandy facies of 

the Jerome Formation ("Sycamore Creek sandstone") 

of Sycamore Creek near the East Verde River has been 

discussed on page 14. Later, Stoyanow (1926, p. 

499) reported additional localities of "Arthrodiran 

sandstone" in the headwaters of the East Verde River 

that represent "a wider range of forms belonging to 

the Arthrodira," but he gave no generic identifications. 

He stated that the "Arthrodiran sandstone" rests on 

limestone member 20 of the Jerome Formation, which, 

as is evident from his stratigraphic section (1936, p. 

497), corresponds to the fetid dolomite unit of this 

report. The "Arthrodiran sandstone" thus is in the 

basal part of the aphanitic dolomite unit. I have not 

found fish plates so low in the section in this area; I 

do not doubt that they occur there, however, because 

the zone containing them would correspond in stratigraphic position to the crossbedded, fish-bearing sandstone at Thompson Wash (section 29). 

MODE OF DEPOSITION AND DIAGENETIC HISTORY 

The central problem posed by the aphanitic dolomite 

unit is the determination of the genesis of its principal 

rock type, aphanitic dolomite. In an attempt to understand the genesis, it is useful first to reconstruct the general environment of its deposition. The present investigations have shown that the aphanitic dolomite 

unit once extended in uniform lithology over an area 

of several thousand square miles. The predominant 

type of sediment was carbonate mud and locally some 

clayey sediment and, more rarely, fine sand. A narrow 

littoral zone of coarser terrigenous sediments was deposited along the shore of the Defiance uplift. 

The occurrence of mud cracks on bedding planes of 

the dolomite and on shaly interbeds shows that the sediment surface, a.t least locally and intermittently, was exposed to the air; therefore, sedimentation in the entire 

area p~obably took place in extremely shallow water, 

perhaps not more than a few feet below low water level. 

Local emergences of the sea floor might have been due 

to occasional exceptionally low tides, perhaps caused by 

coincidence of low spring tides with strong offshore 

winds. An alternative explanation would be a tideless 

sea, not more than about 2 feet deep, where the bottom 

was exposed sporadically at times of persistent strong 

offshore winds. 

The almost perfect preservation of certain primary 

sedimentary structural features, especially intraclastic 
ROCKS OF THE MARTIN FORMATION 41 

brecciation and the like, raises the questipn whether the 

original sediment was a primary dolomitic mud. 

The formation and origin of dolomite rocks have 

been the subject of extensive speculation, sharp deduction, and intensive laboratory studies by chemists and 

geologists. The geochemist's conclusion is summed up 

in the following statement by Graf and Goldsmith 

(1956,p.185): 

It is practically impossible at present to make useful statements about the effects of such variables as salinity, pH, and 

Fe++ concentration upon the rate of dolomite formation. 

Illing ( 1959) believed that cryptocrystalline dolomite may have been deposited as primary dolmnite, or 

"protodolomite" ( Graf and Goldsmith, 1956) mud. 

Primary precipitation of dolomite mud to form aphanitic (or in the Russian terminology, pelitomorphic) 

dolomite has been postulated by several Russian geologists, including Vishnyakov ( 1951), Strakhov ( 1958a), 

Rukhin ( 1958, p. 125-131), and Teodorovich ( 1955, 

1959). Strakhov (1958a) distinguished two principal 

types of dolomite: stratified dolomite and metasomatic 

dolomite. According to Strakhov, "stratified doloInites" are generally of considerable lateral extent (as 

much as several hundred kilometers) ; they are generally mineralogically pure dolomites, and their texture is micrograined to very fine grained ; organic remains are either absent or very rare and if present are 

poorly preserved. Ostracodes and brachiopods are 

commonly characteristic assemblages and are different 

from the assemblages in adjacent limestones. Most 

important, indications of any kind of metasomatic replacement of preexisting calcium carbonate by dolomite 

are lacking. In contrast to "stratified dolomites," metasomatic dolomites, according to Strakhov, are supposed 

to be irregularly lenticular; dolomite rhombohedra 

form in clusters, fossils are dolomitized, and no commonly characteristic fossil assemblages are recognizable. 

Precipitation of primary dolomite mud is, according 

to Strakhov, a process characteristic of arid zones and 

is aided by increased C02 pressure, which he assumed 

existed in the atmosphere during Paleozoic time. 

It would be tempting to apply these criteria to the 

interpretation of the origin and distribution pattern of 

the carbonate rocks of the Jerome Member, but unfortunately, many features of these rocks do not support 

such a simple interpretation. 

The gross lithology of the aphanitic dolomite unit 

corresponds to a certain extent to "stratified dolomites" 

as described by Strakhov. Features that are in agreement with his description are (1) the extent of the rocks 

over thousands of square miles, ( 2) perfect bedding, 

(3) the predominantly aphanitic texture, and ( 4) the 

scarcity of fossil assemblages, which, where present, 

consist mainly of ostracodes, calcispheres (not mentioned by Strakhov), and scattered associated brachiopods. The following features are at variance with 

Strakhov's description: (1) the local formation of 

limestone "islands" or lenses in the aphanitic dolomite 

unit and ( 2) the occurrence in many places of a phanitic dolomites interbedded with coarser grained dolomite of Strakhov's "metasomatic" type and with calcitic 

dolomite in the upper unit of the Jerome. Finally, as 

suggested by experiments carried out by Graf and Goldsmith (1955), the role of C02 pressure for dolomite 

formation has probably been greatly overesti1nated. 

The "metasomatic" types in the Jerome are not lenticular but are well bedded and extend laterally over considerable distances, as is discussed in greater detail 

on pages 42-55. 

Limestone of the aphanitic dolomite unit is invariably aphanitic and is characterized by rich microfossil 

assmnblages of calcispheres, ostracodes, and unidentified fragmentary remains. Most aphanitic dolomite is 

barren, but organic remains are still recognizable in 

some of it, although the remains are commonly much recrystallized and transformed into "ghosts." In such 

aphanitic dolomites containing only faintly recognizable 

fossil remains, the fossils have an appearance similar to 

fossil structures occurring in more coarse-grained dolomite rocks, where they have been entirely or largely 

obliterated during dolomitization. The indications for 

a "metasomatic" origin of the aphanitic dolomites can 

possibly be supported by electron-microscopic studies 

(p. 76). 

Dolomitization of the type that changed the subnlicroscopic crystalline texture of the sediment and destroyed some very delicate fossil structures such as calcispheres and thin ostracode shells but preserved the 

coarser lithological structures such as intraclasts, autobreccias, microlaminations, and others probably proceeded at a very early diagenetic stage, commonly called 

penecontemporaneous. This assumption is discussed in 

connection with the description of the rocks of the upper 

unit of the Jerome Member (p. 85). 

UPPER UNIT 

For the purpose of regional description, all rocks of 

the Jerome Member that lie above the aphanitic dolomite unit are considered as one unit having a rather 

complex lithology and many laterally intergrading facies. The rocks of this member are sandstone, siltstone, 

shale, limestone having different grain sizes ranging 

from aphanitic to biostromal, and dolomite ranging 

in grain size from aphanitic to coarsely saccha.roidal. 

The upper unit of the Jerome as here defined corresponds to the middle and upper units of the Martin 

Limestone as described by Anderson and Creasey ( 1958, 
42 DEVONlAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

p. 50) in the Jerome area and to the middle and upper 

members of the Martin Formation as defined by Huddle 

and Dobrovolny (1952, p. 73) in east-central Arizona, 

especially the Salt River area. The middle and upper 

members, or units, in these two widely separated areas, 

however, are of greatly different lithology. The middle 

unit of Anderson and Creasey consists of fine- to medium-grained mottled dolomite rock; the 1niddle unit 

of Huddle and Dobrovolny consists of a lower sandstone and an upper limestone unit. The upper unit of 

Anderson and Creasey is characterized by diverse lithology; it consists entirely of carbonate rocks having 

greatly varying texture, composition, and appearance. 

The upper member of Huddle and Dobrovolny is composed mostly of sandstone, siltstone, shale, and some 

interbedded limestone units. The relationship of the 

middle and upper units or members in one classification 

to those in the other is unknown and cannot be ascertained. Any correspondence would he coincidental. 

Study of the cross sections A.-A' to 1-I', given in 

plates 28-31, indicates that in many places the rock 

sequence above the aphanitic dolomite unit can be subdivided into two or three lithologically distinct units, 

but none of these parts persist laterally far enough to 

be recognizable in all parts of the area of investigation. This sequence, therefore, must be regarded as one 

unit having a greatly varying and, in places, abruptly 

changing lithology. 

In sections where the Jerome is fully formed-that 

is, where all its three units are present-the upper unit 

ranges from 125 to more than 300 feet in thickness. 

Toward the northeast, beyond the limits of distribution 

of the fetid and aphanitic dolomite units, it laps onto 

Precambrian basement rocks that have a slightly undulating topography, and in this onlap area it ranges 

in thickness from a few feet to 250 feet. In the northwestern part of the study area, the upper unit is represented by a very pure carbonate facies that is composed 

almost entirely of dolomite rock. In the southeastern 

part of the area and in the onlap area on the northeast, 

siliceous-detrital beds having a variable but locally considerable thickness are present; the distribution of these 

beds is discussed in more detail on pages 47-55. 

Because of the facies differentiation of the upper 

unit in different parts of the area, description of this 

unit has been arranged in a manner that deviates from 

that adopted for the more uniform fetid and aphanitic 

dolomite units. In description the upper units is eli-' 

vided into areas that have certain facies features in 

common, and description of rocks and fossils is integrated for each area. The broader implications of 

facies distribution in the upper unit is discussed in the 

chapter on sedimentation (p. 84-85). 

TYPE SECTION 

In the type section of the Jerome Member (section 

41) the upper unit as here defined is 308 feet thick. 

The lower 113 feet corresponds to the middle member 

of Anderson and Creasey ( 1958) . All the rocks are 

dolomite containing more than 19.5 percent MgQ (fig. 

3). The total carbonate content varies from about 67.5 

percent to 98 percent (pl. 23). In most rocks impurities constitute less than10 percent. 

As Anderson and Creasey observed, the rocks in the 

lower part of the unit are characterized by conspicuous 

mottling. The mottling is mostly red, yellowish red, 

and yellow in hue, but medium- to light-gray colors are 

also present. Bedding is thin to medium, and texture 

is mostly fine graineq to suba phanitic. Different grain 

sizes are intimately mixed in some rocks. The rock (a 

thin section of which is shown in plate 7, figure 4) is 

subaphanitic in megascopic aspect. In fact, it consists 

of a crystalline dolomitic groundmass that is composed 

of crystals 0.02-0.05 mm in diameter and is permeated 

by clouds of less transparent material composed of dolomite crystals less than 0.02 mm in size. Since this 

"cloudy" material has an orientation approximately 

parallel to the bedding planes, it probably represents a 

recrystallized primary structure of the sediment. 

The rocks of the lower part of the upper unit are 

rather pure carbonates containing an insoluble fraction 

mostly of about 5 percent (pl. 23) . Detrital quartz can 

only rarely be recognized as a conspicuous component in 

thin sections. 

Fossils are not uncommon in this part of the section, 

but all are too poorly preserved for identification. 

However, the remains that are recognizable suggest a 

varied fauna of brachiopods, gastropods, fishes, and assorted microfossils such as ostracodes and calcispheres 

(pl. 8, fig. 3). This abundance of fossil remains contrasts with the scarcity of fossils in the underlying 

aphanitic dolomite unit. 

The upper 195 feet of the upper unit is more varied in 

lithology than the lower part. Texture ranges.~ from 

aphanitic to medium grained, and the fine- to mediumgrained rocks tend to be saccharoidal-that is, they 

have a large proportion of idiomorphic dolomite crystals-and on weathering tend to disintegrate into a 

fine sand composed of individual dolomite grains or 

crystals. 

The insoluble fraction of this part of the upper unit 

varies considerably from bed to bed (pl. 23), and in 

many rocks the detrital quartz component is much in 

evidence in thin section. Quartz grains larger than 1 

mm in diameter are scarce. Most larger grains are considerably etched, and their peripheries are replaced by 
ROCKS OF THE MARTIN FORMATION 43 

dolomite. Grain -size analysis of insoluble residues reveals a well-defined cyclic pattern of deposition in this 

part of the section (pl. 23), which is discussed on pages 

71-73. 

A few thin shaly interbeds, which have not been 

studied in detail, are present. 

Some beds in the upper part of the upper unit have 

a considerable porosity resulting from the presence of 

vugs that are either empty or filled with crystalline 

ealcite. In subunit 32 the vugs form eavities as much 

as half an ineh in diameter. 

Fossils are present in many be.ds, though they are 

mostly poorly preserved exeept where silicified. The 

best fossiliferous horizon is subunit 31, which eontains 

an abundance of silieified corals of diverse types 

(Tabulophylltt/m? sp., and cyathophylloid and amplexoid corals as identified by W. A. Oliver, Jr., written 

commun., 1959). This subunit is about at the level of 

unit 7 in Stoyanow's seetion ( 1936, p. 498) of the J erome Formation, from which he reported a more diversified fauna composed of "Syringopora and Aulopora 

in commensa1ity with Stromatopora. Zaphrentoid 

eorals. Fish plates. Braehiopods." Thus, some lateral 

variation in paleontologic faeies seems to exist, but as 

far as I have been able to ascertain, these fossiliferous 

dolomites "'ere never formed into bioherms or reefs, as 

asserted by Stoyanow. In the section here studied, 

these beds eould not even be called biostromal, although 

biostromes may possibly have been formed elsewhere 

at about this stratigraphie level. 

FACIES WEST AND NORIXH OF JEROME 

In 1953, the Devonian section in Hull Canyon (section 42), about %-1 miles southwest of Jerome, was 

studied in some detail; however, sampling was not done 

according to the same standard applied in 1956, and 

no detailed section description, therefore, is given. In 

the upper part of this seetion are two richly fossiliferous 

dolomite beds about 80 and 100 feet, respeetively, below the top of the Jerome Member. This position is 

slightly higher stratigraphically than the coralliferous 

dolomite, subunit 31, in the Jerome section (section 41) . 

These two beds contain a rich eoral fauna, whieh has 

been identified by W. A. Oliver, Jr., as follows: 

Lower horizon ( TP 376) : 

Breviphyllttm sp. 

eyathophylloid corals 

zaphrentoid corals 

Di8phyllum spp. (3 species) 

H cxagonaria spp. ( 2 species) 

"A_ulopora" spp. (2 species) 

thamnoporoid coral 

745-106 0-64-3 

Upper horizon (TP 378) : 

Tabtt~ovhyllum? sp. 

horn corals undet. 

Hexagonada spp. (3 species) 

Alveolites sp. 

"Aulopora" sp. 

thamnoporoid coral 

stromatoporoid undet. 

Both beds are riehly fossiliferou&-almost biostromal-but no biohermal buildups occur. The lower 

bed also eontains Amphipora? sp., Oyrtospirifer sp. and 

Platyrachella sp. The upper bed contains, in addition 

to the foregoing fossils, stromatoporoids and Plalyrachella sp. A layer containing abundant specimens of 

Thamnopo,ra oeeurs about halfway between the two 

beds. 

The seetion at Hull Canyon is made up entirely of 

dolomite rock and therefore bears close lithologic 

resemblanee to the seetion at Jerome. 

Toward the north the place closest to Jerome where 

the Jerome Member was examined in detail was on the 

north side of the Verde River, just west of the junction 

of Sycamore Creek about 8 miles north of Jerome (section 43). Here, the Tapeats( ?) Sandstone crops out at 

the foot of the cliffs close to the riverbank, but an easttrending fault that extends parallel to the outcrop and 

the riverbank cuts off the contact between the sandstone 

and the basal part of the Jerome Member. The fetid 

dolomite unit is not exposed, and the oldest rocks seem 

on the north side of the fault are some of the lower 

beds of the aphanitic. dolomite unit. 

Except for the top 10 feet, the upper member here 

consists entirely of dolomite rock, in which saecharoidal 

texture is prevalent. Most beds are very finely to finely 

crystalline, but some are medium and eoarsely crystalline. Rock colors are almost entirely yellowish red and 

yellow in hue. Significant amounts of_ detrital quartz 

.grains are restricted to a few beds such as in subunits 21 

and 25. 

In contrast to the section at Jerome, no aphanitic dolomites occur in the upper unit at the Verde River locality. 

Also, mottling is less common than a;t Jerome, and 

where present it is more like irregular and spotty lamination. Invertebrate trails occur in the unit on the bedding planes; possibly, the primary cause of the mottling 

is the action of burrowing organisms in the original calcareous mud. 

Weathering disaggregates many of the dolomite 

rocks, even the fine-grained and very fine grained varieties, into a sandy or silty powder consisting of individual dolomite grains. This disaggregation is due 

mainly to the removal of interstitial calcite, aided perhaps by the weakening effect of the vuggy porosity of 

many of the rocks (pl. 8, fig. ·2). This type of weathering is especially pronounced in the upper part of the 
44 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

upper unit. It may have been responsible for the impression (Stoyanow, 1936) that the uppermost part of 

the Jerome Member becomes increasingly 1nore sandy 4 

north of Jerome, whereas in fact the total carbonate 

content is very uniform throughout the entire area. A 

10-foot sandstone subunit at the top of the section may 

be of local extent only. 

The section along the Verde River (No. 43) does not 

contain many fossiliferous beds; the more important 

such beds are in subunits 23 and 26. Subunit 23 includes one abundantly fossiliferous bed containing 

"A ulopora" sp., Tharwn.opo11a sp., and unidentified 

rugose corals, stromatoporoids (W. A. Oliver, written 

commun., 1959), and brachiopods. 

Of greater interest is subunit 26, in which 1nembers 

of a small, unique fauna described by Stoyanow (1941) 

were found. Stoyanow did not indicate the exact stratigraphic position of this fauna, but he stated that it 

came from the "Island Mesa beds," which he previously 

described (Stoyanow, 1936) as a sandy facies of the 

Jerome Formation and in which he included the upper 

125 feet of the formation in this locality. The fauna 

contains, among other species, 0 ongeriomorpha a:ndru801'i Stoyanow and A rizonella allecta Stoyanow and 

is restricted to the lower 2 feet of subunit 26. From 

the upper part of the same unit vV. A. Oliver, Jr., (written commun., 1959) identified the corals Bre,viphyll'lt1n ~ 

sp. and H exagona.ria sp. From the same horizon, B. 

F. Glenister and R. M. Liebe (written commun. by 

Glenister, 1960) reported the following conodonts: 

Polygnathus norrn,.alis Miller and Youngquist 

Palmatolepis tria,ngula7"is Sannemann 

Hindeodella sp. 

Synprion.ioditna sp. 

Spathognathodus sp. 

Falcod1ts? sp. 

indeterminate fragments 

This assemblage is of late Frasnian age. 

The section (No. 44) at Elden Mountains, about 20 

miles northeast of the upper Verdi River, is of interest 

because of its isolated geographic position and because 

it provides a valuable control point in the midst of the 

San Francisco volcanic field. After the presence of 

Devonian rocks had been recognized by Brady (1933, 

1934), Stoyanow ( 1936, p. 501) reported 148 feet of 

partly arenaceous and shaly limestones. During the 

present investigation, a sequenee of about 181 feet of 

dolomite and slightly ealcitie dolomite roeks was measured ( seetion 44). These are mostly fine to medium 

grained and generally rather pure and have an insoluble fraetion amounting to less than 10 percent in n1ost 

samples (pl. 23). The general lithology is typical 

4 In German and French geological terminology, saccharoidal dolomite 

is called sandstone-Dolomitsandstein, sable dolomitique. 

for the upper part of the upper unit of the Jerome 

Member. 

Fossils are generally poorly preserved. Amphipora 

was reeognized in one or possibly two subunits ( 1 and 

9) ; brachiopods and ostracodes, in others. Stoyanow 

reported the presence of "Oladopora" (probably 

Thamnopora) and Atrypa as well as fish remains, including teeth. Hussakof (1942) described the following fishes from an unidentified horizon of the Mount 

Elden section : 

Goccosteus arizonensis Hussakof 

Dinichthys 2 spp. 

Pyctodus bradyi Hussakof 

Dipterus sp. 

This assemblage is dated as early Late Devonian by 

Hussakof. 

THE AREA SOUTHEAST OF JEROME 

There are no significant ehanges in the lithologic 

eharaeter of the upper unit for a considerable distance 

southeast of Jerome, as far as can be judged from the 

widely spaced outcrops. (See also fig 31.) 

At Chasm Creek (section 39), 28 miles southeast of 

Jerome, only the lowennost 76 feet of the upper unit 

was seen. The rocks here are mostly finely crystalline 

dolomites, medium to thiek bedded, and extremely hard. 

Braehiopods and gastropods are present in some beds 

(subunits 20 and 22), but they could not be freed from 

the rock or identified. The eolor is mostly yellowish red and light gray in hue. 

Southeast of Chasm Creek no outcrops occur until 

the junction of East Verde and Verde Rivers is reached; 

there a seetion at Limestone Hills ( seetion 38) was investigated. The thickness of the upper unit is only 218 

feet, but possibly the full thickness was not seen. The 

lithology differs somewhat in detail from that at the 

typical seetion at. Je-rome. Mottling is not conspicuous 

in the dolomite beds, although it does oecur in some. 

The rocks of the unit are uniformly rather finely erystalline except for an aphanitic limestone in the lower part 

(subunit 18) that is hjghly fossiliferous (pl. 8, fig. 1), 

though 1nost of the fossils are fragmentary. This 

limestone is notable in that it is the only rock seen in 

this survey that contains remnants of echinoids. Another lin1estone unit (subunit 21) contains some indeterminable fish pbtes and is notmYort.hy for its luster 

mottling (pl. 9, fig. 1) of the kind described on pages 72 

and 73. 

The remainder of the section above subunit 21 is 

eomposed of dolomite roc.k that is mostly fine grai~1ed 

and generally admixed with varying mnounts of detrital 

quartz. Fossils are scarce except at the top of the 

section, which has yielded the corals Bre1-'iphyllitm sp. 

and H exagonaria sp. ('V. A. Oliver, Jr., written commun., 1959), and large numbers of the brachiopods 
ROCKS OF THE MARTIN FORMATION 45 

Camarotoechia sp. and Oranaena? sp. These brachiopods forn1 a coquina containing very little dolomitic 

cement (fig. 31). 

UPPER EAST VERDE RIVER AND PINE CREEK AREAS 

Sedimentation in this area was influenced by a land 

area of undeterrninecl size on which no Devonian sedirnents were deposited and 'vhich is here called Pine 

Island. The eomplex geologic conditions, doubtless 

eomplieated by younger tectonic movements, are evident frmn the descriptions of Stoyanow (1942, p. 1266-

1270). He ealled this area the Pine Creek Ridge and 

regarded it as part of the "Payson Headland," the bulk 

of which was, according to hirn, situated to the south. 

Huddle and Dobrovolny ( 1952, p. 80) referred to the 

area as Pine Ridge, which they interpreted as one of 

three northeast-pointing prongs of Mazatzal Land. Detailed study of several stratigraphic sections in this 

eritical area, however, supports a somewhat different 

paleogeographical interpretation. Sections 34 (Tonto 

Natural Bridge) and 33 (Upper Sycamore Canyon) 

are of particular interest. 

The se·ction at Tonto Nat ural Bridge has been referred to in several earlier publications, but it had 

never previously been studied in detail. 

Rocks of the upper unit at Tonto Natural Bridge are 

an even more heterogeneous assemblage than those of 

the aphanitic dolomite unit at the same locality. (See 

cross section H-H' of pls. 22 and 30.) Nearly all the 

physical properties of the rocks~insoluble residue, 

MgO content, and grain size of the carbonate rocks~ 

change abruptly in vertical sequence. The section has 

a greater percentage of calcitic dolomites than is common in the upper unit, and although there is not much 

sandstone, n1any of the dolomites contain high percentages of siliceous-detrital material. A few limestone subunits (21 and 39) are probably representative 

of the rocks of the upper unit before dolomitization. 

These subunits are aphanitic to very fine grained; most 

contain abundant fragmental microfossils-especially 

calcispheres and ostracodes-and a sprinkling of dolomite rhombohedra and scattered small authigenic 

doubly terminated quartz crystals (pl. 8, fig. 5). 

The top subunit of the section is a very calcitic dolomite that contains abundant stem fragments of a large 

crinoid, which are the only megafossils in the Tonto 

Nat ural Bridge section. Remains of the same large 

crinoid species occur associated with brachiopod and 

coral assemblages in the upper part of the upper unit in 

some other localities. 

Dolomites containing a greater or lesser amount of 

detrital quartz (pl. 7, fig. 3; pl. 9, fig. 3) occur in the 

upper unit. Quartz grains, particularly the large ones, 

show varying degrees of peripheral etching and dolomite replacement. An extreme example in which the 

original shape of the quartz grains has been greatly altered by dolomite replacement is shown on plate. 9, 

figure4. 

In some dolomites a considerable amount of calcitic 

substance-partly of very minute size-fills vugs; the 

substance possibly represents recrystallized remnants 

of the original aphanitic rnatrix (pl. 8, fig. 4). 

From the presence of ealcispheres, crinoids, and ostracodes in undolomitized or little dolomitized rocks at 

this loeality one may conclude that the entire sequence 

of Tonto Natural Bridge was formed in a rnarine envir·onment; the high terrigenous detrital component 

suggests that sedimentation was probably close to land. 

vVhereas outcrops are discontinuous south of Pine 

Island, probably largely because of faulting, outcrops 

east of Pine Island are continuous and give a clearer 

concept of the depositional environment. 

The onla p of the Jerome Member on the east side of 

Pine Island can be observed near the junction of the 

Pine-Payson Road and the road from J(ohl Ranch to 

Pine (Pine quadrangle, BM 5676), where Red wall 

Limestone rests on Precambrian Mazatzal Quartzite 

(fig. 18) . Frmn here eastward the Devonian section 

thickens very abruptly, and about 1 mile to the east, 

it is 467 feet thick; 65 feet of this thickness is Beckers 

Butte Member, and the rest is Jerome Member (section, 

fig. 18) . Half a mile south of BM 5676-near BM 

5735-outcrops of conglomerate and massive dolomite 

beds are found on the west side of the highway, where 

they lie on a smooth surface of Mazatzal Quartzite. 

Downhill from the road at this point the slope is formed 

by Mazatzal Quartzite, which is overlain by about 200 

feet of pale-red sandy saecharoidal dolomite at the bottom of the creek. The dolomite is capped by Redwall 

Limestone. A few hundred yards to the south, the 

base of the dolomite is at the level of the road, and in 

outerops west of the road, the dolomite is underlain by 

gray and brown sandstone. These rocks, as well as the 

conglomerates on the west side of the highway, represent the onlap facies of the upper part of the upper 

unit of the Jerome Member. 

Increase in thiekness of the beds from this area 

eastward is so rapid that one might suspect downfaulting rather than onlap, were it not for the fact that 

the Red wall Limestone truneates the Devonian-Precambrian contact (fig. 18) ; nowhere else in this area-or 

anywhere in Arizona for that matter-is there any 

evidenee of pre-Redwall faulting after Precambrian 

time. Abrupt stratigraphie abutments of the Devonian 

roc.ks against Precambrian high areas were previously 

shown on very generalized diagrams published by 

Stoyanow (1942, p. 1267) and by Huddle and Dobrovolny ( 1952~ p. 81). 
46 

w 

A 6000' 

5750' 

5500' 

0 

DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

EXPLANATION 

.., ~ v.., '01:"" £. 

, ,.. ~ "(' ~ ,..., v.., ~ "£,. t-1 

L 7 L- ,_"'f 'OJ \1 

Basalt 

Redwall • Limestone 

~ Martin Formation 

Pattern indicates conglomerate 

1 MILE Mazatzal • Quartzite 

~------- Contact 

Dashed where approximate 

Fault 

··I:o···········~·······································-~·-····· 

-.:> 

-.:> 

0 

Upper unit 

Fetid and aphanitic units 

Beckers Butte Member 

0 1 MILE 

Jl 

}'z lfl<( 

lii(L 

~0.. 

~Ui 

} 

z 

<( 

z 

0 

> w 

0 

} I 

~z <(<( 

Uwn:: 

O:::lll 

0.. 

.... 

Q) 

.0 

E 

Q) 

::2: 

Q) 

E 

e 

Q) 

...., 

E 

A' 6000' 

5750' 

5500' 

FIGURE 18.-Geology of area southeast of Pine. South of BM 5676 the Martin Formation rests on the Mazatzal Quartzite. Immediately 

east of BM 5,676 the Redwall Limestone rests on the Mazatzal Quartzite. The section illustrates the abrupt pinchout of the Martin Formation westward toward Pine Island. F indicates the Theodossia horizon of section 33, subunit 37. The hill immediately west of 

Sycamore Creek is composed of sandier material. 
ROCKS OF THE MARTIN FORMATION 47 

In section 33, measured in the upper part o:f Sycamore Canyon about 1 mile east o:f the Pine-Payson 

Road, both the Beckers Butte and the Jerome Members are complete and typically :formed. About 281 

:feet o:f the upper unit rests on the :fetid and aphanitic 

dolomite units, here 117 :feet thick. The twofold division that is typical in the Jerome area is vaguely recognizable. The rocks o:f the lower part o:f the unit from 

the base to about subunit 22 are somewhat mottled, and 

two aphanitic subunits (27 and 35) were observed in 

the upper part. Most- of the dolomite rocks are very 

fine to medium grained and saccharoidal. No limestones are present except near the top of the unit. Subunits 38 and 40 are noteworthy :for being completely devoid of fossil remains, even microfossils, whereas the 

interbedded dolomites, subunits 37 and 39, contain 

brachiopods; subunit 37 contains brachiopods in large 

quantities ( T heodossia and others; equals horizon F 

in fig.18). 

Most of the dolomites in the same section contain 

varying amounts of detrital quartz; more quartz is 

found in the lower than in the upper part. A 20-:foot 

bed o:f sandstone having a matrix composed of calcitic 

dolomite occurs at the base o:f the upper third o:f the 

unit. 

On the whole, although it is close to a land areaPine Island-the entire section of the Jerome Memberin this locality contains remarkably little terrigenous 

material. 

East and southeast o:f Sycamore Canyon, the upper 

unit has thicknesses of generally more than 200 :feet. 

At 'Vebber Creek (section 31), thickness is only 200 

feet, and the beds contain a considerable proportion 

of sandstone and some shale. All dolomite beds tend to 

be mottled, and no true aphanitic rocks are present, except limestone subunit 31. Large mud cracks were observed in fallen blocks o:f subunit 22, which are either 

a very fine grained highly calcitic dolomite or possibly 

a slightly dolomitic limestone. 

The sandstone beds in this locality are fine to medium 

grained, and subunit 36 contains large ripple marks, 

having crests 1-11h inches apart. Abundant :fragmentary fish plates were found near the base o:f the unit in 

a fine-grained somewhat silty saecharoidal dolomite 

(subunit 20). This subunit is possibly identical with 

the "Arthrodiran sandstone" mentioned by Stoyanow 

( 1936, p. 499) found near the headwaters of the East 

Verde River. 

Fossils are somewhat more common in the upper part 

of the unit. Most noteworthy is limestone subunit 31, 

which contains a microfauna including the genus "U mbella" Maslov. Other than this locality, "Umbella" has 

been recorded only from Belgium and from various 

localities in southeastern European Russia (pl. 20, fig. 

2; pl. 21). This genus is discussed on pages 103-105. 

An Atrypa assemblage occurs in the middle o:f the uppermost subunit (No. 37). 

South o:f Webber Creek the upper unit is poorly exposed in the triangle between the East Verde River, 

Sycamore Creek, and east o:f the Pine-Payson Road 

(section 32). Siliceous-detrital beds are of little importance. Most of the unit consists probably o:f dolomite and calcitic dolomite. Fossils in the upper part 

o:f the unit include Amphipora, H exagonaria, Thanvnopora (fig. 26), and Atrypa. 

East of the upper East Verde River, the upper 

member retains more or less the sa,me characteristics. 

In the excellent exposures along Diamond Rim, little 

siliceous-detrital material is present, except :for a :few 

thin sandstone beds and a 13-foot shale subunit (No. 43 

of section 30) near the top. Although present, mottling 

is not particularly conspicuous in the dolomite beds in 

this section. The amount of siliceous-detrital material 

in the dolomite beds varies greatly, but it is generally 

less in the upper part than in the lower part o:f the unit. 

Fossils are common throughout the uppermost 50 or 60 

feet and abundant in the top limestone subunit (No. 

46), which carries a rich thanotocoenotic assemblage of 

stromatoporoids, Disphyllum, Syringopora (W. A. 

Oliver, Jr., written commun., 1959; fig. 24 o:f this report), and Atrypa. 

THE NORTHEASTERN ONLAP BELT 

Along the northeastern onla p belt, the marginal sandy 

:facies o:f the aphanitic and :fetid dolomite units wedges 

out, and the upper unit is transgressive over the Precambrian of the Defiance uplift (pl. 27). Good exposures are :found in the upper Tonto Creek area, along 

Christopher Creek, and in uppermost Canyon Creek; 

all occur along a belt :following the foot o:f the Mogollon 

Rim, where these relations can be studied (pl. 29; cross 

seetion G-G', pl. 30). In the onlap belt o:f the upper 

unit, basal sandstone beds are mostly present, and near 

the margin of the :fetid and aphanitic dolomite units, 

the basal sandstone :facies o:f the upper unit is locally 

indistinguishable from the marginal sandstone :facies 

of the two lower units. Boundaries accordingly are 

somewhat arbitrary on the maps o:f some localities. 

In one area o:f undetermined but probably small size, 

the upper unit is missing, as can be seen in good outcrops 2 miles east of the junction o:f Christopher and 

Tonto Creeks on the road to Christopher Creek Camping Area (section 24) . Here, Red wall Limestone, 

brecciated by pre-Pennsylvanian weathering, rests on 

a slightly irregular surface o:f Precambrian quartzite. 

In pockets below the Redwall, as much as 15 :feet of 

sandstone is present locally that is considered to represent the upper unit of the Jerome. Indications are that 
48 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

an area of partial absence of the upper unit extends 

north ward from these exposures for an unknown but 

probably small distance. Absence of the upper unit is 

due to nondeposition as well as perhaps to a slight 

amount of pre-Redwall erosion. This area is 2-3 miles 

east of the "Cristopher Mountain Ridge" of Huddle and 

Dobrovolny (1952, p. 91, fig. 25, and pl. 13). The name 

Christopher Island is here proposed for the area because 

of its proximity to Christopher Creek. Christopher 

Mountain is at least locally covered with Devonian 

rocks, as is discussed in following paragraphs. 

West of the Christopher Island area the facies rela.-

tions at three important localities were studied: section 

29 (Thompson Wash), section 28 (Kohl Ranch) and 

section 27 (junction of Tonto and Horton Creeks). In 

all these loca1ities, the fetid and aphanitic dolomite 

units are represented in part or entirely by sandstone 

facies and, in sections 28 and 29, the boundary between 

these units and the upper unit is somewhat arbitrary. 

In each locality all basal sandstone units have been included in the aphanitic dolomite unit, although they 

may in part belong to the upper unit. In section 27 

basal sandstone subunits are overlain by 6 feet of dolomite and 9 feet of 1nottled aphanitic dolomite, all of 

which are included in the aphanitic dolomite unit. 

In the three localities the upper unit is characterized 

by considerable sandiness and generally by abruptly 

varying lithologies. A typical sandy dolomite rock is 

illustrated on plate 9, figure 7. In the coarsely crystalline dolomitic matrix, outlines of pellets or clasts can 

clearly be distinguished, and they have no relation 

to the crystallinity pattern. Their presence suggests 

that the original rock was a fine-grained or aphanitic 

pelletal or clastic limestone. The quartz grains are well 

rounded and have much overgrowth. In some beds the 

quartz grains ·are greatly shattered, evidence indicating 

that they were either transported by torrents or perhaps 

redeposited from preexisting sandstone. 

In the three sections (Nos. 27, 28, 29) the upper unit is 

characterized by large amounts of limestone and dolomitic limestone; dolomitization of the limestones of the 

upper unit was less complete in this area than elsewhere. 

The formation of layers composed mostly of euhedral 

dolomite crystals of minute size caused microlamination 

of the rock (pl. 9, fig. 2) and illustrates one way in which 

the rock was dolomitized. Intermixed in these layers are 

silt-size quartz grains, which tend to be 1nore abundant 

than in the nondolomitized limestone matrix. 

Stylolites, whieh elsewhere are scarce in these carbonate roeks, were observed in one fine-grained dolomite 

from sect:ion 29, subunit 12 (pl. 8, fig. 6). 

As in most other places fossils are present in the upper ha.lf of the unit, though they deerease in abundance 

from southwest to northeast. The upper half of the 

unit in section 29 is very fossiliferous; predominating 

faunas are stromatoporoids, rugose and tabulate corals, 

crinoids, and brachiopods. The fossils are mostly silicified, and one bed (subunit 21) is a completely silicified limestone and, in part, a brachiopod coquina. 

In the Kohl Ranch section (No. 28) , one very fossiliferous limestone unit (No. 32) that is rich in corals and 

brachiopods occurs at the top; a few less fossiliferous 

beds occur lower in the section. 

In section 27 (Tonto and Horton Creeks), subunit 19 

near the top of the section is the only bed containing 

abundant megafossils. It contains a very rich thanatocoenotic association of Di8phyllum sp. and "Aulopora" 

sp. (fig. 25). This is a persistent horizon which can be 

traced for more than half a 1nile along the slope east 

of Tonto Creek north of its junction with Horton Creek. 

Search for microfossils might be rewarding in other 

subunits, as is shown by the record of an "Umbella" or 

"Umbella"-like fossil in the medimn- to coarse-grained 

standstone of subunit 9 near the bottom of the unit (pl. 

9, fig. 6). This is an unusual type of occurrence for this 

kind of fossil, which is generally restricted to aphanitic 

to very fine grained limestones. 

The upper unit thins east of Tonto Creek. A· good 

section is exposed in Doubtful Creek (section 26) immediately below the Kohl Ranch-Young Road, where 

the upper unit is·represented by 175 feet of rock, mostly 

dolomite, resting on altered volcanic rocks of Precambrian age. All the rocks in this section are of similar 

color hues-predominantly pale red, pinkish gray, grayish orange, and pink and light gray. 

A feature of this section is the number of small intraformational disconformities, which are generally uncommon in other measured sections of the upper unit. 

The top subunit is a sandy limestone. The rest of the 

section, except for a few clastic beds, is composed of 

dolomite, most of whieh contains varying a.mounts of 

detrital quartz. The proportion of detrital material increases somewhat from the bottom to the top of the section (pl. 22). No identifiable fossils were found in this 

section, but fragmental brachiopods were noted in subunit 15. 

Between Doubtful Creek and the Christopher Creek 

Camping Area, outcrops of the Jerome Member are 

very poor or lacking. A poorly exposed section consisting of about 39 feet of unfossiliferous sandstone and 

calcitic dolomite was measured near the stables of Boy 

Seout Ranch No. 1 (section 25). Its base is not exposed, and although the thickness of the missing part 

cannot be accurately estimated, it is probably not great. 

Thus, thinning of the Jerome from the Doubtful Creek 

area to near the Christopher Creek Camping Area is 

probably gradual. 
ROCKS OF THE MARTIN FORMATION 49 

On the south side of Christopher Creek in this area, 

outcrops of dolomite beds dip about 20° N. and overlie 

a basal sandstone bed several feet thick. No good section was located. Silicified brachiopods were seen in 

one bed, and the nearness of Redwall Limestone outcrops 'vas suggested by the presence of boulders of 

crinoidal limestone containing single rugose corals. 

Presence of tilted Devonian and probably also Mississippian beds at the foot of the northern slope of 

Christopher Mountain is evidence that these sedimentary rocks formerly extended into the area south of 

Christopher Creek. As the beds on the north side of 

the creek at Boy Scout Ranch No. 1 are horizontal, an 

east-trending fault may extend along the creek or a 

steep flexure may exist in this area. On the south side 

of this fault or flexure, the Paleozoic beds have been uplifted. The occurrences of Devonian and Mississippian 

rocks at the top of Christoper Mountain (described in 

section 19), near its eastern termination, give further 

evidence for the uplift. These occurrences suggest that 

Christopher Island did not extend appreciably south 

of the small area where the island is now exposed. 

Since the island constituted a source of the detrital material fot1nd in the sedimentary rocks surrounding it, 

the continuation of the island must be sought to the 

north of section 26, where it is now concealed by the 

Paleozoic rocks of the Mogollon Rim. 

East of Christopher Island the facies and thickness 

pattern is almost a mirror image of that on the west 

side. (See line of cross section F -F' in pl. 27.) The 

Devonian beds generally have a slight northerly dip 

and rest with an angular unconformity of as much as 

90° on Mazatzal Quartzite. Outcrops, though mostly 

poor, reveal the presence of sandstone and sandy dolomite and a gradual increase in thickness, which is perhaps sommYhat less gradual than on the west side. Fossils are absent from rocks nearer the island (sections 

23, 22, and 21) . The sandiness in these sections is 

greater than that occurring over a comparable distance 

to the west of the island. A typical sandy dolomite 

from this area is shown in plate 10, figure 1, A lustermottled dolomite from section 22 is shown in plate 10, 

figure 2. 

Fossils do not appear until about 2112 miles east of 

Christopher Island, where, in section 20, the rugose 

corals Disphyllrum and Stringoz)hyllu.m ~ occur in the 

top subunit, a sandy dolomite. The carbonate rocks 

in this section are composed of dolomite and are sandy; 

sandstone occurs only in the lowermost part (subunits 

1, 2, and 5). 

Farther east the Jerome Member occurs at the 

eastern end of Christopher Mountain, at an altitude of 

about 6,700 feet, which is roughly 900 feet above the 

bottom of Christopher Creek. The section here has a 

minimum thickness o£ 144 feet, nearly all of which 

consists of dolomite (section 19). The dolomite in the 

lower half of the section (subunits 2-8) has ·a surprisingly high carbonate content, commonly more than 

90 percent (pl. 22). Total carbonate content varies 

considerably among the units in the upper half of the 

section. Abundantly fossiliferous beds containing 

Amphipora, globular stromatoporoids, corals, brachiopods, gastropods, and calcispheres indicate normal 

marine sedimentation at a moderate distance from the 

shore. Excluding those in limestone unit 15, all fossils, 

especially the stromatoporoids, are highly dolomitized 

and are generally recognizable only on weathered rock 

surfaces. 

Because of poor outcrops below the base of the exposed part of this section, its total thickness cannot be 

estimated, but it probably does not greatly exceed 150 

feet. 

Southeast of Christopher Mountain the line of outcrops and of measured sections is roughly parallel to 

the edge of the onlap area of the upper unit. (See cross 

sections E-E', D-D', and 0-0' on pl. 29 and the northwestern end of A-A' on pl. 28.) However, the first 

three of these cross sections (E-E', D-D' and 0-0', pl. 

29), though short, are at high angles to the onlap edge 

and thus provide some information on facies shifts in 

a direction perpendicular to the shore. (See p. 92-94.) 

Along the belt from Colcord Canyon south of Turkey 

Peak and along N aeglin Rim, the general cha.racter of 

the Jerome Member changes little (sections 16, 17, 18), 

although it varies in detail. The upper unit rests on 

Precambrian rocks, and its thickness along this belt 

varies little from 200 feet. The bulk of the rocks is 

composed of dolomite, generally fine to medium crystalline, and contains a generally decreasing amount of 

siliceous-detrital material from bottom to top and only 

a few interbedded sandstone layers. 

Toward the top of these sections, limestone beds occur 

that are everywhere fossiliferous. At Colcord Canyon, 

li1nestone subunit 17 contains a rich microassemblage 

that includes calcispheres, tintinnids(?), pteropods, and 

ostraeodes (pl. 16, fig. 2; pl. 17, fig. 2). Other members 

of the limestone assemblages, which occur also in associated calcitic dolomites, are Amphipora, ThamrnopoTa, 

Schizophoria, Atrypa, Platynachella, and probably 

others. The top subunit (No. 21) of section 18 (2 miles 

south of Turkey Peak) contains a rich superbly preserved taphocoenotic assemblage consisting predominantly of Schizophoria cf. S. iowensis (Hall), Atrypa 

devoniana var. bentonensis Stainbrook, Sp·inatrypa cf. 

S. rotunda Stainbrook, Oyrto8pirifer whitneyi (Hall), 

and, less abundantly, Tlwmnopora sp. (fig. 29). 

The sandstones in the same sections are generally 

medium grained and not well sorted; the grains are 
50 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

considerably angular (pl. 10, fig. 5), and the rocks have 

no carbonate cement. 

Dolomites range from fine-grained pelletal to coarsegrained saccharoidal. Plate 10, figure 6, illustrates an 

interesting rock type consisting of two distinct modal 

forms of dolomite crystals. Mostly euhedral dolomite 

rhon1obohedra ha,ving an average size of 1 mm diameter 

are embedded in a "matrix" of anhedral dolomite crystals about one tenth thei~r size. Thoroughly mixed rocks 

such as the sandy dolomite sho-wn in plate 11, figure 2, in 

which grain size of the crystalline dolomitic matrix is 

roughly equal to that of the terrigenous quartz grains 

also are included. 

Some unusual rock types are present in the, N aeglin 

Rim section (No. 16), especially in subunits 6 and 7. 

Subunit 6 crops out in knolls suggesting biohermal 

buildups, but no fossils are evident either megascopically or in thin section. The bulk of the rock is a dolomite breccia as seen both mega:scopically and microscopically (pl. 11, fig. 1). Small bodies of elliptical or ovoid 

outline, illustrated in the lower left of plate 11) figure 1, 

are either dolomitized ooids, or more probably calcispheres because no oolites have been recognized anywhere among unaltered carbonate rocks of the Jerome 

Member. 

The rock of this subunit is composed of fragments 

consisting of aphanitic to very fine grained dolomite. 

All the larger clasts are angular, but many small one&-

about 1 mm in size-are rounded, indicating that the 

water was slightly turbulent. 

Detrital qua,rtz grains llire sca.ttered through the rock, 

the larger of which are generaily well rounded (pl. 11, 

fig. 3) . Some quartz grains (as shown on the same illustration) are surrounded by a halo of finely crystalline dolomite, which contrasts sharply with the surrounding aphanitic matrix. The origin of this feature 

is not clear. The halos could be considered to be a dolomitized peripheral shell of the quartz grains whose 

original size is indicated by the outer circumference of 

the halos. However, this interpretation is contradicted 

by observations on a similar ~rock from south of Turkey 

Peak (section 18, subunit 1). In this rock the groundmass is an aphanitic dolomite containing many rounded 

clasts of somewhat darker aphanitic dolomite and numerous quartz particles ranging in size from silt to very 

fine sand. In addition, larger grains of various composition and as much as 2-3 nnn in diameter are present. 

Plate 11, figure 4, shows a representative thin section in 

which the typical groundma.ss and fine quart.z detritus 

and three larger grains-composed of quartz (top), 

chert (lower left) and aphanitic dolomite (lower 

right) -are present. All three grains are surrounded 

by halos composed of finely crystalline translucent dolomite, but the same type of dolomite is present also in 

irregular clouds throughout the groundmass. Clearly 

the dolomite surrounds some of the smaller quartz 

grains, and a larger compact area of it is seen below the 

chert grain in the lower left corner of the thin section. 

The described conditions can probably be best explained by assuming recrystallization of aphanitic 

dolomite and the formation of a two-stage dolomite 

rock. A somewhat similar rock from the Carboniferous 

of the Russian Platform was described by Khvorova 

( 1958, pl. 57' fig. 336). 

Evidence to support this assumption is found in a 

rock type occurring in the upper part of the overlying 

subunit (No. 7). This rock is ~an intimate mixture of 

finely crystalline and aphanitic dolomite (pl. 10, fig. 3). 

A few calcispheres occur in the aphanitic portions. 

The crystalline dolomite was formed by grain growth 

of the aphanitic dolomite and is not secondary cement, 

because without the crystalline dolomite the aphanitic 

rock particles form an open network that could not have 

existed in nature. 

From Naeglin Rim northeastward, the section diminishes in thickness. Fortunately, good outcrops are 

present near the head of Canyon Creek close to the 

foot of the Mogollon Rim. Two miles south of the 0. 

W. Ranch on the west bank of the creek is a fine outcrop of a channel fill in Precambrian rocks (section 14) . 

Surprisingly, the channel contains little sandstone but 

is mostly filled with sandy dolomite and calcitic dolomite (pl. 12, fig. 3) . Possibly this was not strictly a 

channel but rather was ·a wider panlike depression in 

which sandy lime mud was deposited and later 

dolomitized. 

Good exposures (section 15) of the Jerome Member 

occur 1 mile upstream from this locality, where the 

Jerome rests with only a slight unconformity on Dripping Spring Quartzite. The basal sandstone is thicker 

here than in the "channel" of section 14. Most of the 

original sediment in this area was composed probably of 

very finely intraclastic calcareous mud that contained 

much detrital quartz. Some of this mud is still preserved as limestone (pl. 11, fig. 5), but in other beds, it 

has changed to fine- or medium-grained saccharoidal 

dolomite (pl. 13, fig. 3). 

In both sections (Nos. 14 and 15), fossiliferous beds 

occur in the uppermost part. The assemblages include 

stromatoporoids, Thamnopora, Atrypa, Platyrachella, 

and calcispheres; all are typical members of associations found in the uppermost part of the upper unit 

elsewhere. 

Southeast of sections 14 and 15 and lower down Canyon Creek valley, the rocks of the marginal onla p belt 

were studied at sections 45, 10, 11, and 9. In this area 

thickness and lithology vary greatly because of the channeling of the Devonian rocks into the underlying Precambrian. In measured sections the thickness of the 
ROCKS OF THE MARTIN FORMATION 51 

upper unit ranges from 36 feet at section 10 to 135 

feet at section 45. In spite of the small thickness, the 

lithology is diverse in these sections, and the rocks 

consist of sandstone, limestone, biostromal limestone, 

silicified limestone, and dolomite. Almost all the carbonate-rock units are very fossiliferous. At the top 

of biostromal subunit 2 in section 10 is a very rich assemblage of horn corals, Disphyllum? n. sp., and Tabulophyllum n. sp. The limestone beds of section 10 are 

especially rich in calcispheres. Among megafossils the 

common association of atrypids and Schizophoria and 

a biostromal limestone of stromatoporoids and tabulate 

corals occur. Large colonies of Spongophyllum occur 

in the lower part of section 45; characteristic associations of Macgeea, Tabulophyllu-m, Thamnopora, Arnphipora, and massive stromatoporoids, Atrypa, and 

spiriferids are also found in the upper part of the same 

section. 

In the poorly exposed outcrops of Devonian rocks 

about halfway between sections 10 and 45, about due 

east of the ahmdoned Chediski farm, large numbers of a 

very massive species of Ohaetetes,5 forming large cylindrical colonies, were found. 

These faunal associations, which correspond to those 

commonly found in the top part of the upper unit, indicate that the area near sections 10 and 11 remained land 

during much of the time when the rocks of the upper 

member were being deposited and may well have furnished the material for some of the sandstones in the 

lower parts of·that unit in sections to the west and to 

the south. 

Farther southeast good outcrops occur in the escarpments east of the so-called Oak Creek Indian Farms and 

on the north side of the road leading from this locality 

to Grasshopper. The thickness of the upper unit seems 

to be variable, because a section of about 80 feet in 

thickness was measured by Huddle and Dobrovolny 

(1952, p. 101) very close to my section 9, which has a 

thickness of 142 feet. Both sections lie in sec. 32, T. 

8 N., R. 16 E. Out of the total of 142 feet in section 9, 

more than 72 feet consists of limestone or silicified limestone, which is an unusually high limestone ratio, particularly if the fact is considered that the section has 

only one 5-foot unit of calcitic dolomite (subunit 14). 

The rest of the exposed rocks consist of sandstone. 

It is, thus, not surprising that the rocks of this section 

are abundantly fossiliferous. Nearly all limestone beds 

are rich in calcispheres (pl. 17, fig. 1; pl. 18, fig. 1). 

Other microfossils include ostracodes (unidentifiable) 

and pteropods, proba,bly Styliolina (pl. 13, fig. 1). 

5 Helen Duncan (written commun., 11)61) identified the Chaetetes but 

questions the Inclusion of Chaetetes as a faunal element in these 

Devonian rocks; she suspects that the specimens were obtained from 

younger rocks. Field evidence, however, suggests that these corals are 

indeed Indigenous to Devonian rocks. 

Some limestones show considerable recrystallization of 

the type shown from another locality on plate 12, figure 

6. 

Fossil assemblages vary much from subunit to 

subunit. One 2-foot limestone bed in sootion 9 

that i.s almost biostromal contains Actinostroma sp., 

Anostylostroma sp., and Stictostroma sp. (identifications by W. A. Oliver, Jr.). Unit 14 possibly contains 

Arizonella, a gastropod that is a member of a unique 

assemblage occurring in the upper part of section 43 

(discussed on page 62 of this report). The brachiopods are represented by typical associations of species of 

Schizophoria, Atrypa, and Spinatrypa. Theodossia c£. 

T. hwngerfordi occurs near the top in subunit 25 together with a rich assemblage of Hexagonaria ocddens 

Stumm and Thamnopora sp. 

The limestones are mainly aphanitic to very fine 

grained. Recrystallization through grain growth is 

evidenced by calcispheres that are completely surrounded by clear crystalline calcite. Plate 10, figure 4, 

illustrates a similar type of limestone that does not contain calcispheres but contains much silt-size to finegrained detrital quartz. The fine-grained quartz is 

concentrated mostly in the unaltered aphanitic limestone, but some quartz grains are surrounded by crystalline calcite. 

The lower sandstones, up to subunit 6, are siliceous 

and well cemented (pl. 12, fig. 5). In the upper part 

of the section, sandstones are more commonly calcareous. Plate 12, figure 4, illustrates part of a calcareous 

sandstone bed in which the cement, recrystallized into 

crystals several millimeters in size, constitutes more 

than 50 percent of the rock. 

A comparison of this section with section 10 of Huddle and Dobrovolny (1952, p. 102) shows differences in 

detail but also great similarities, particularly in fossil 

content. 

THE AREA FROM MIDDLE CANYON CREEK TO THE UPPER 

SALT RIVER 

The southwestern edge of the outcrop belt of Devonian rocks is continuous from the southeastern corner 

of Navajo County east of the middle part of Canyon 

Creek, across the middle Salt River Draw, and ~nto the 

upper Salt River area. Excellent outcrops m Lost 

Tank Canyon also belong to this belt but are 

separated from outcrops on the east side of Canyon 

Creek by the broad valley cut into Precambrian rocks 

by the Salt River. Along the entire belt, where completely exposed, all three units of the Jerome Member 

a.re present·. The member is underlain by the Beckers 

Butte Membe-r, which varies greatly in thickness. The 

relations of the Devonian rocks in the area are illus-
52 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

trated by cross sections (',_0' in plate 29 and A-A' and 

B- B' in plate 28. 

Outcrops in Lost Tank Canyon (sections 12 and 13) 

are of great interest because the more eastern of these 

(section 12) is not more than 2lj2 miles from the area 

where the fetid and aphanitic dolomite units wedge 

out; yet all units exposed in the outcrops have typical 

thickness and lithology. The only indication that the 

rocks exposed here were close to the shore is the presence 

of sandstone subunits (Nos. 17, 20 of section 12) in the 

basal part of the upper unit. These basal sandstones 

are absent to the west in the upper part of Lost Tank 

Canyon (section 13). In both localities sandstone units 

are present in the upper part of the upper unit. The 

carbonate units are less dolom itic and more fossiliferous. Biostromal limestone beds contain Gerronostroma 

and ldiostroma (identified by W. A. Oliver, .Tr., written 

commun. 1959). Amphipora is abundant in dolomite 

units in the lower and middle part of the upper unit, 

but in these places as in many others its skeletons can 

be generally detected only on weathered surfaces (fig. 

19). Immediately above the biostromal subunit 34 in 

section 12 is an aphanitic limestone that is very irregularly dolomitized. In one thin section made from this 

rock (pl. 12, figs. 1 and 2) dolomite rhombohedra are 

scattered in some areas but crowded in others where they 

have almost entirely replaced the original rock. 

Brachiopod assemblages in section 12 are few. There 

is a coquina composed of Theodossia cf. T . hungerfordi 

in subunit 44 (fig. 27) and a coquina of Atrypa in subunit 45, but brachiopod faunas are much richer and 

more varied to the west. In section 13, four distinct 

assemblages are found: ( 1) Oyrtospirifer-Platyrachella-Spinatrypa (subunit 19); (2) Theodossia cf. T. 

hungerfordi (subunit 21); (3) Sch-izophoria-Oyrtospirifer-Theodossia-Atrypa-Spinatrypa (subunit 23) ; 

and ( 4) Theodossia sp. (subunit 24). These are among 

the richest brachiopod assemblages found in the upper 

unit. They are easily accessible in outcrops close to the 

Heber-Young highway. 

Sandstones in the upper unit are mostly fine grained 

and well sorted. Plate 13, figure 5, illustrates one example in which sutured contacts were formed between 

an unusually large number of grains. 

As mentioned on page 51, the Devonian outcrops 

in Lost Tank Canyon lie northwest of a continuous outcrop belt of Devonian rocks that extends generally 

southeastward and then disappears under younger volcanics south of the Salt River or dips below younger 

Paleozoic rocks only a mile or so above the junction of 

White River and Black River. Information available 

for this belt is presented in cross section A- A' on plate 

28. Data from descriptions of sections 6 (Rockhouse 

Butte) and 8 (Cliff House Canyon) by Huddle and 

Dobrovolny (1952) were used as supplemental information. 

The lithology of the upper unit along this belt is 

very variable. Clastic detrital units occur at irregular 

intervals, though they generally increase in proportion 

southeastward. Limestone beds are not uncommon in 

the upper part of the unit and tend to form minor biostromal subunits. Dolomite rocks, which generally 

make up about one half of the total thickness of the 

upper unit, represent the lithology typical of the upper 

unit of the .Jerome Member where the member is predominantly carbonatic. Although mottling is not a 

predominant feature, the color and texture of the rocks 

are similar to those of the rocks of the typical .Jerome 

Member. The rocks are very fine to medium grained 

and predominantly medium to light gray and yellowish gray in hue. 

Particularly complex and abundant vertical facies 

changes are common in the upper unit in the area east 

of middle Canyon Creek and middle Salt River Draw 

(fig. 20). 

FIGURE 19.-Fine-grained dolomite, slightly calcitic, containing Amphipora skeletons, which are recognizable on weathered surface 

although their microstructure has been obliterated through dolomitization. Section 12, Lost Tank Canyon, upper unit, subunit 28. X 1.5. 
ROCKS OF THE MARTIN FORMATION 53 

FEET 

40,--,-------------------~~~~~~ 

23 

35 

30 

20 

15 

Sandstone, 

quartzose , 

thick-bedded , 

crossbedded 

Lim estone. 

fine-grained . 

unfossiliferous 

Biostrome made up of 

Adinostroma, Alveolites, Thamnopora, 

Hu uyonurin, Po.chyphyllutn 

Limestone with Atrypa. Thamnopora 

Sandstone. quartzose. coa rse-grained 

Biostrome made up of 

/d:iostroml t ? , Ge·rrmw.qt mnUI 

Dolomite. 

fine-grained . 

unfossiliferous 

FIGURE 20.-Typical facies sequence of the upper unit of the Jerome 

Member in t he middle Canyon Creek area; abrupt changes of contrasting rock types, are illustrated. Section 8, east side of Canyon Creek, 

subunits 19-23. 

This area, in which sections 6, 7, and 8 are located, is 

relatively inaccessible, and these sections were not 

studied and sampled in the same detail as most others. 

A large nondolomitized area probably exists here; accordingly, further study would provide additional data 

on the primary sedimentary facies of the carbonate 

rocks of the upper unit. Some of the primary sedimentary facies is exemplified by subunit 18 of section 6 

(lower Salt River Draw), which consists of a very fine 

grained to aphanitic rock containing abundant microfossils such as calcispheres, tintinnids (?), pteropods, 

and unidentified fragmental remains (pl. 13, fig. 4; pl. 

16, fig. 1). Also, stromatoporoid biostrome units are 

present everywhere in the arett and as far south as 

Sawmill (section 1; pl. 27). 

In the area east of middle Canyon Creek, the lower 

half of the upper unit is characterized by considerable 

amounts of sandstone, some of which is medium grained 

and crossbedded. Locally this sandstone is poorly 

sorted and contains angular grains. 

In the upper Salt River area (sections 2, 3, and 

4), siltstone and shale are more abundant, whereas sandstone is less abundant. This distribution is due to the 

fact that the sections from Canyon Creek to Black 

River (cross section A-A', pl. 28) lie along a line that 

diverges slightly from the edge of the onlap belt of the 

upper unit. Most probably sections 2--4 indicate conditions of deposition that existed farther offshore than 

those indicated by sections 6-8. 

Huddle and Dobrovolny (1952) recognized the presence of a "green shale zone" at or close to the top of the 

Jerome Member in the upper Salt River .area. This 

zone is well exposed in roadcuts along U.S. Highway 60 

on the north side of the Salt River Canyon (fig. 21). 

As shown on cross section A-A' on plate 28, it can be 

traced northwestward into Salt River Draw, but it 

seems to disappear east of Canyon Creek and is absent 

in Lost Tank Canyon. It represents a tongue of the 

siltstone-shale facies in the upper part of the upper 

unit of the Black River section (section 2) . 

Traces of burrowing by mud-feeding animals are 

abundant in the shale, although they can be recognized 

only in freshly weathered rock specimens. Included 

are unidentified horizontal, more or less straight burrows and U-shaped, horizontally oriented burrows of 

the U-in-U type (fig. 30E), which may be identified as 

Rhizocorallium. 

Fossil content of the rocks of the upper unit is considerable in the Canyon Creek-Salt River Draw area, 

partly because of the greater abundance of limestone 

beds and partly because of the greater abundance of primary life. The presence of biostromal limestones has 

already been mentioned ( p. 52). They are built up 

mostly by the stromatoporoids I diostroma? sp., Gerronostroma sp., and, locally, Pachyphyllum sp. Corals 

are abundant in some beds-for example, subunit 22 of 

section 8, from which "\iV. A. Oliver, Jr., identified eight 

species of corals and one species of Actinostroma. According to Oliver (written commun. 1959), the age of 

this fauna is Frasnian. In nearby section 7, Tabellaephyllum peculiaris Stumm, also identified by Oliver, 

was obtained from the top of subunit 5; it is a species 

that was formerly known only near Bisbee, Ariz. The 

brachiopods of this area have not been studied in detail. 

Subunit 26 of section 8 consists of a coquina that is composed of Theodossia and is similar to the one in Lost 

Tank Canyon, but it contains a much richer admixture 

of compound rugose and of tabulate corals. In addition spiriferids and atrypids are generally present in 

these upper beds. 
54 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

Microassemblages include the common association of 

calcispheres and ostracodes along with scattered pteropods and tintinnids(?). 

Near the Salt River the beds change into a facies 

that is virtually unfossiliferous as a result, at least 

partly, of the high state of dolomitization of the carbonate rocks. Section 3 has yielded only poor Sohizo-

]Jhoria renmins in subunit 33; section 4 has only one 

densely packed Atrypa layer in subunit 20 and calcispheres and Amphipora in subunit 18. In shale and 

siltstone beds of section 3 straight and branching invertebmte tracks, some of them large, are observed 

(fig. 22). 

In the silty facies farther southeast, brachiopods are 

very abundant. Thus, some of the siltstone units in 

section 2 are very fossiliferous. By far the most predominant are atrypids, including Atrypa cf. A. olarkei 

"'Warren, A. devoniana var. bentonensis Stainbrook, and 

Spinatrypa cf. S. rot~mda Stainbrook. Also present, 

though rarer, are Oyrtospirifer cf. 0. ~ohitneyi Hall and 

Devonoprodu.ot1t8? sp. Corals seem to be absent in the 

J erori1e Member in this area. 

A richly fossiliferous section was studied near Sawmill (section 1), 10 miles south of the Salt River, 

roughly south of Flying V Canyon (section 3). The 

sequence here is an alternation of sandstones and limestones or dolomitic limestones. Most conspicuous in 

outcrops along roadcuts is biostromal subunit 4, section 

1, composed entirely of colonies of Stictostroma and 

other, unidentified, stromatoporoids, and of Pachyphyllum sp. (\,T. A. Oliver, Jr., written commun., 1959). 

The top subunit (No. 8) of section 1 is especially rich 

in atrypids (Atrypa cf. A. devoniana var. bentonensis 

Stainbrook, Spinatrypa cf. S. rotunda Stainbrook, 

"Atrypa" owenensis Webster). 

THE ROOSEVELT-GLOBE AREA 

Sections of the Martin Formation are well exposed 

on the south side of Theodore Roosevelt Lake, especially 

immediately southeast of the dam (fig. 8). The BeckFIGURE 21.-Top of Jerome Member in Flying V Canyon, roadcut of U.S. Highway 60. Light-colored beds on top are Redwall Limestone; 

below them are thin .. bedded sandstone and thick shale subunits ( 33 and 34, thickness 58 ft) of section 3. Sandstone at base. 
ROCKS OF THE MARTIN FORMATION 55 

ers Butte Member at this locality (described on p. 24) 

is overlain by a complete section of the Jerome Member, 

which in turn is capped by Redwall Limestone (section 36). An equally well exposed and complete section of the Jerome Member on the north side of the 

dam has not been studied in detail. 

The upper unit on the south side of the dam is 263 

feet thick; about half of it consists of sandstone and 

shale. The siliceous-detrital component forms much 

of the lower part and all of the upper part of the unit. 

The middle part consists predominantly of dolomite 

and calcitic dolomite, some of which is sandy and crossbedded. This part is rather fossiliferous, although 

most fossils are poorly preserved. The section on the 

north side of the dam contains a coquina composed of 

Schizophoria at about this same stratigraphic level (fig. 

28). 

The succession of rocks in the upper unit at Windy 

Hill, 4.5 miles to the east of Theodore Roosevelt Dam, 

is similar. In 1957, drought had lowered the level of 

Theodore Roosevelt Lake sufficiently to expose the base 

of Windy Hill. The lowest stratigraphic subunit then 

exposed in this section was the dolomite of the aphanitic 

dolomite unit conta.ining the "brown rind chert." 

In the upper unit, the basal sandstone is 68 feet thick 

(compared with 96 feet at Theodore Roosevelt Dam). 

The basal beds contain no intercalations of dolomite 

and are composed entirely of sandstone; some of this 

basal sandstone is crossbedded. The middle and upper 

parts of the upper unit ha.ve almost the same lithology 

as those at Theodore Roosevelt Dam. The middle part is 

mostly dolomitic and contains scattered layers of crinoid plates, brachiopods, and fish plates. The upper 

part consists of siltstone and shale, as at Theodore 

FIGURE 22.-Underside of siltstone bed on which are casts of large 

innrt ~rnte tracks, photographed almost vertically from below. The 

large str aight track on the left is about 4 Inches wide. Upper unit of 

Jerome Member, In roadcut on west side of Flying V Canyon, near 

section 3. 

Roosevelt Dam, but is topped by a small thickness of 

unfossiliferous dolomite. 

The geologic map of Gila County (Wilson and others, 

1959) shows another area of Devonian rocks on the 

north side of Theodore Roosevelt Lake, opposite Windy 

Hill, but this locality was not visited. 

No outcrops of Devonian rocks occur southeast of 

Windy Hill for about 20 miles-as far as the upper 

Pinal Creek and Pinto Creek area, where Devonian and 

Mississippian rocks are present in small fault blocks 

(Peterson, 1954). 

At Pinal Creek, about three-quarters of a mile southeast of Hoore's qua.rry and about 3lj2 miles northwest 

of Globe, the upper unit is much thinner (203 feet) 

than elsewhere. It consists predominantly of silty 

rocks; carbonate rocks here are few (section 35) . Both 

the siltstones and the dolomites in the section are richly 

fossiliferous, but the fauna consists almost entirely of 

brachiopods in which the atrypids predominate. 

An intrastratal solution surface was observed between 

subunits 9 and 10 (fig. 23). Intrastratal erosional 

phenomena of this kind were only rarely observed in 

rocks of the upper unit. 

FOSSIL FAUNAS AND PALEOECOLOGY 

NOTE ON TERMINOLOGY 

Many stratigraphers and paleontologists use the term 

"biocoenosis" for fossil assemblages in which individual 

fossils occupy the same place and position they had 

when the animals were alive; they use the term "thanatocoenosis" for fossil assemblages in which individual 

fossils have obviously been transported. (For example, 

see Shrock and Twenhofel, 1953, p. 22.) An example 

of biocoenosis would be a fossil coral reef; an example 

of thanatocoenosis, a coquina limestone. Thus, Boucot ( 1953) stated that "an excellent example of a thanatocoenosis is the miscellaneous assortment of organic 

debris gathered on most marine bea.ches." Such usage, 

however, is not correct. 

The term "biocoenosis" was proposed by Mobius 

( 1877; translation 1880, p. 723) for "a community 

where the sum of species and individuals, being mutually limited and selected under the average external 

conditions of life, have, by means of transmission, continued in succession of certain definite territory". Such 

a community is the "total number of mature individuals 

of all species living together in any region." Therefore, 

a. biocoenosis, according to Mobius, is not a two-dimensional concept, but rather the time dimension must be 

added. Occupancy for a period of time is a necessary 

adjunct of a biocoenosis. 

Manifestly, there can be no such thing as a fossil biocoenosis. Although the time factor may be substant1ated through stratigraphic observations, no as-
56 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

semblage of fossils represents "all species living together in any region," because every biocoenosis has constituent species that cannot be fossilized. 

Realizing this, Wasmund (1926) suggested the term 

"tha.natocoenosis," primarily for fossil assemblages in 

which individual fossils had retained position ·and orientation of the living animals. Wasmund did not fail 

to point out that primary thanatocoenoses are different 

from the biocoenoses from which they originate and 

that they may be secondarily modified or destroyed. 

"Thanatocoenosis," therefore, is an available term for 

occurrences in which large numbers of fossils are found 

in the positions and orienttttion that the animals had in 

life. They are the remains of animals that were united 

in death. Hessland (1943, p. 55) called this a "preserved biocoenosis" ( konservierte Biozonose) lacking 

allochthonous additions. This term is virtually the 

same as the "fossil community" of Craig ( 1953) and the 

"life assemblage" of Boucot ( 1953) . 

Hedgpeth (1957, p. 40) recently deplored the inconsistent usage of the term "thanatocoenosis" by paleontologists, and Hutchinson (1957, p. 686) pointed out 

FIGURE 23.- Intraformational solution surface in lower part of upper 

unit of Jerome Member at Pinal Creek (section 3.5). The hammer 

rests on subunit 8 (silty dolomite). .l ust above the hummer point is 

the bottom of su bunit !l (fine-grained, laminated dolomite), ; the top 

of subunit 9 wa s greatly eroded before deposition of subunit 10 

(silty dolomite), which fills the solution pockets at top of subunit 9. 

that fossil associations "are not associations of living 

but of dead organisms; they are thanatocoenoses, not 

biocoenoses." However, not all fossil associations fall 

into this category. 

If the remains of the animals in a biocoenosis after 

their death are transported and dispersed, no thanatocoenosis is preserved in the sediment or, later, the rock. 

Remains of animals from one biocoenosis may be sorted 

and separated and become buried in different places, or 

remains from different biocoenoses may be washed together and buried in one place. For such assemblages 

the term "taphocoenosis," or burial assemblage, proposed by Quenstedt (1927) seems appropriate. This 

useful tenn, although long familiar in German literature, as Schmidt (1958) observed, has been overlooked 

or neglected by English-language geologists. Instead, 

the term "thanatocoenosis" is often misleadingly used 

for taphocoenotic assemblages. 

Hessland (1943, p. 55) and Davitashvili (1945) independently proposed the term "necrocoenosis" for nonthanatocoenotic fossil associations, and the same term 

was coined again by Tasch ( 1953, 1955). However, in 

the definition of Tasch (1955, p. 207), the term refers 

to any kind of fossil ·assemblage. On the whole, the 

word "necrocoenosis" seems inappropriate as applied to 

invertebrate fossils because the Greek noun nekros 

means a dead person or a human corpse. 

The term "paleobiocoenosis," introduced by Hecker 

( 1960, p. 19), is a synonym of thanatocoenosis in its 

proper meaning. The term "paleothanatocoenosis," 

proposed by the same author in the same place, seems 

redundant because all thanatocoenoses are ancient. 

For the foregoing reasons, the following recommendations are made: ( 1) Application of the term "biocoenosis" to any kind of fossil associations should be 

a voided; ( 2) the term "thanatocoenosis" should be applied to strictly "residual biocoenoses" such as fossil 

coral reefs, oyster banks, and the like ; and ( 3) the term 

"taphocoenosis" should be used for nonthanatocoenotic 

fossil assemblages in which, as a rule, the exact place of 

derivation of individual component specimens is unknown. 

DISTRffiUTION AND OCCURENCE OF FOSSil. GROUPS 

Although the fossil fauna of the upper unit of the 

Jerome Member is variable in its distribution, it is uniform in its general aspect and composition. No complete census of the fossil species can be made until the 

large fossil collections have been studied in greater detail. In most faunas the skeletons and shells are silicified. Incomplete silicification is rather common, 

especially in brachiopods. In such shells only a thin 

outer film has been converted to silica; within the film 

the rest of the shell consists of crystalline calcite (pl. 
ROCKS OF THE MARTIN FORMATION 57 

14, fig. 2). This type of preservation is particularly 

cmnmon in lin1estones and dolomitic li1nestones in the 

upper part of the unit. Such shells are virtually impossible to ext.ract from the rock, because if the rock is 

placed in dilute hydrochloric acid, even if very weak, 

the C02 bubbles that form break the shells into 

frag~nents. 

In many rocks, however, the shells are very well preserved, as shown in figures 24-31, and excellent faunas 

can be obtained. 

In the following paragraphs, the occurrence of fossils according to phyla is discussed and, where possible, 

their relationship to definite lithologies and their areal 

distribution are indicated. 

Protozoa 

The Protozoa are possibly represented by tintinnids, 

if the interpretation of the fossils in question is correct 

(pl. 13, fig. 2; pl. 16, figs. 1 and 2). They are described 

n1ore fully on pages 97-99. These tiny bell-shaped 

shells occur in aphanitic limestones and have so far been 

found only in rocks from Salt River Draw (section 6) 

and Colcord Canyon (section 17). The preferred facies 

of these somewhat questionable forms agrees with that of 

the true tintinnids of the Mesozoic, which generally occur in fine-grained to aphanitic limestones. 

Some authors have referred to the Protozoa all those 

fossils that are here treated as undifferentiated calcispheres as ·well as larger spherical calcitic bodies, 

which are included in the genus Urrnbella Maslov (non 

d'Orbigny) . These fossil forms are here regarded as 

having an uncertain origin and are discussed on pages 

103-105. 

Stromatoporoidea 

The occurrences of stron1atoporoids fall into two 

sharply divided classes of rocks that are characterized 

respectively by A1nphipora. and by large massive forms. 

Amphipora is a rather small form that builds delicate dendroid colonies, characteristically consisting of 

a reticulate coenostem having an axial canal, and 

thus is easily distinguishable from tabulate corals having a sin1ilar size and skeletal form. The genus was 

-found at nearly every locality where the upper unit of 

the Jerome Member was studied. As is typical for 

Amphipora (Teichert and Talent, 1959, p. 10; Jux, 

1960, p. 245, pl. 23, fig. 2), individuals occurred generally in great numbers and excluded most other forms 

of life. In any given section of the upper unit of the 

Jerome Member, the genus characterizes generally one 

or more thin beds that are commonly not 1nore than a 

few inches thick. 

Observations on mode of occurrence of Amphipora 

else·where suggest that such beds may have a considerable horizontal extent and that they could be traced possibly between adjacent sections and even farther. In 

the Jerome Member, however, extensive dolomitization 

has made their preservation a matter of chance. In fineto medimn-grained dolmnites, the presenee of Amphipora colonies is indieated locally only by vague outlines 

of their skeletons on weathered surfaces (fig. 19), even 

where thin sections reveal that dolomitization has colnpletely obliterated all mieroscopic organic struetures. 

Dolomitized An~phlpora beds, therefore, are easily overlooked, and the record of occurrences of A1nphipora in 

measured sections is probably very incomplete. 

Amphipora is mainly a Devonian fossil, although 

older and younger occurrences have been documented 

(Lecompte, 1956, p. F142). Until comparatively recently the genus was almost unrecognized in North 

America, but it is now known from 1nany localities--

particularly in the "\Yestern part of the continentfrom rocks of Middle and Late Devonian age. (See map 

by Helen Duncan, in Cloud, 1959, p. 948.) 

In eontrast to the very common occurrence of Amphipora, the distribution of large spherical forms of stromatoporoids is more narrowly restricted. In Devonian 

rocks these forms are major constituents of biostromal 

and biohermallimestone buildups. In the upper unit 

of the Jerome Member, the following genera of massive 

stromatoporoids have been identified by "'\¥. A. Oliver, 

Jr. (writtent comn1un., 1959): Actinostroma, Anostylostroma, Gerronostroma, and Stictostroma; associated 

with these locally is a larger dendroid form, I diostroma. 

These genera tend to form biostromal limestone units 

most of \Vhich are not more than a few feet thick. In 

any given section of the upper unit, generally only one, 

but in places two, such biostromal units may be present. 

The stromatoporoids may build up a biostrome alone or 

they may be joined by compound rugose corals, most 

commonly by Pachyphyllum, and in places by tabulate 

corals. 

The biostrome facies in the upper unit of the Jerome 

~iember (pl. 27) occurs in tt belt that extends southward 

from the Spring Creek area along Canyon Creek and 

Salt River Draw and as far as the Sawmill area (section 1). Massive stromatoporoids occur outside this 

belt but not in biostromal buildups. I saw no true reefs 

or bioherms such as reported by Stoyanow ( 1936) and 

by Huddle and Dobrovolny (1946b, 1952), but I do not 

doubt that biohermal buildups may occur loeally. Gradational transition between lenticular biostromes and 

bioherms would make the distinction a matter of 

definition. 

Anthozoa 

Most commonly rugose and tabulate corals occur together, but locally and in individual beds, one group 

may predominate or exclude the other. The following 
58 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

is a synoptic list of _species present in the upper unit 

(compiled in part from a written report by W. A. 

Oliver, Jr., 1959) : 

Solitary rugose corals: 

BreviphyUum sp. 

Stringophyllu.m? sp. 

Tabulophyllum sp. 

Tabulophyllum? sp. 

Cyathophylloid corals 

Zaphrentoid corals 

Amplexoid corals 

Phaceloid rugose corals : 

Disphyllum sp. 1 

D.sp.2 

D.sp.3 

D.sp.4 

Disphyllum? n. sp. 

Massive rugose corals : 

H emagonaria occidens Stumm 

H.sp.1 

H.sp.2 

H.sp.3 

H.sp.4 

Pachyphyllum sp. 1 

P.sp.2 

Spongophyllum sp. 

Tabellaephyllum pecuUaris Stumm 

Tabulate corals: 

Chaetetes sp 

Strlatopora? sp. 

Thamnopora sp. 1 

T.sp.2 

T. sp.3 

Alveolites sp. 1 

A.sp.2 

Aulocystis ? sp. 

"Aulopora" sp. 1 

"A." sp.2 

Syringopora sp. 

unidentified thamnoporoid corals 

Thus, some 30 species of corals are present in the upper 

unit; most of them have not yet been studied and described in detail. 

From bottom to top of the unit, coral faunas increase 

in abundance and variety; the richest faunas are generally found in the upper 100-150 feet of the unit. 

The solitary Rugosa are not generally conspicuous in 

fossil assemblages, but they occur locally in great 

numbers-for example, at the top of the biostromal 

limestone in section 10 (Spring Creek Canyon). 

Disphyllum is widely distributed, either alone or in 

association with massive Rugosa or tabulates (figs. 24 

and 25). 

Among the massive Rugosa, H exagonaria. and Pachyphyllum are the most widely found. Pachyphyllum 

was among the earliest reported fossils of Devonian age 

in this part of Arizona and was often identified as 

Acervularia david8oni. (See Reagan, 1903, pl. 30.) 

This genus also is found with the .stromatoporoids in 

the biostromal facies but occurs commonly also in other 

coral associations. H exagona.ria occurs generally in 

mixed assemblages in association with other corals and 

with brachiopods. Spongophyllum has been found in 

section 45 only. According toW. A. Oliver, Jr. (written commun., 1960), the species may be the same as S. 

martinense Stumm of the Martin Limestone of southeastern Arizona. 

Among tabulate corals Thamnopora is by far the 

most commonly represented genus, and in many beds it 

occurs alone (fig. 26). Like An&phipora, the branches 

of Thamnopora colonies are se~n in many outcrops on 

weathered surfaces, even on ent'irely dolomitized rocks. 

The habitat of the colonies is similar to that of the 

"Rasenriffe" (meadow or turf reefs) of German literature, which are not reefs but are horizontally extensive dense growths or thickets of branching corals, 

genera:lly composed of one specie,s. (See, for example, 

Hotz and others, 1955, p. 64, 76, 95.) Branching tabulate and phacelloid rugose corals formed this kind of 

biota in Devonian times in many parts of the world. 

Thamnopora also appears as a constituent of fossil 

assemblages in association with other corals and with 

brachiopods. In some beds such as the top unit at section 1 (Sawmill) and the top subunit in section 18 

(south of Turkey Peak) it is the only coral in association with.brachiopod assemblages. 

Some of the very mixed associations are described 

on pages 65 and 66. 

Bryozoa 

Fragments of fenestellid Bryozoa are exceedingly 

rare in calcitic dolomite or dolomitic limestone. They 

form a negligible part of the fauna, and no identifiable 

specimens were collected. 

Brachiopoda 

The total nmnber of brachiopod species, when properly studied and identified, will almost certainly be 

found to exceed 20. The most important species in the 

upper unit of the Jerome Member are the following 

(identifications by P. E. Cloud, Jr., 1960, or by author 

and verified by Cloud) : 

Sell izophoria iotV"ensis (Hall) 

S. cf. S. iowensis (Hall) 

Nervostrophia sp. 

Devonoproductus cf. D. 1.iUlgaris Stainbrook 

Stenoscisma n. sp. (possibly new genus) 

Oamarotoechia sp. 

Atrypa devoniana var. bentonensis Stainbrook 

A. cf. A. pronis Fenton and Fenton 

"Atr11pa" owenensis 'Vebster 

Spinatrypa cf. S. rotunda Stainbrook 

S. cf. S. albertensis (Warren) 

Platyracl!ella cf. P. mcbridei (Calvin) 

Oyr·tosph·iter whitneyi (Hall) 

Tenticospir·iter aft'. T. cyrtinatormi8 (Hall and 'Vhitfield) 

Theodossia cf. T. lwngerfordi (Hall) 
ROCKS OF THE MARTIN FORMATION 59 

Brachythyrina aff. B. strigosa 

Uranaena? sp. 

The composition of the brachiopod faunas varies very 

much from place to place and also from bed to bed in 

a stratigraphic section. (See p. 52.) Brachiopods 

are probably the most common fossils in the upper unit 

of the Jerome Member. In the lower part of the unit, 

they are generally poorly preserved and have not boon 

collected. In the upper part, brachiopods tend to be 

more or less completely silicified, and many excellent 

assemblages have been obtained by dissolving fossiliferous rocks in hydrochloric acid. 

T'-vo typt>s of brachiopod assemblages can be distinguished: (1) mixed assemblages in which several species occur together and that as a rule contain associated 

coral faunas, and (2) restricted assemblages that consist of only one species or of a few species belonging to 

one genus (for example, Atrypa and Spinatrypa) and 

that tend to form coquinoid limestones or true coqumas. 

Mixed assemblages generally contain species of several different genera (Schizophoria, Atrypa, Spinatrypa, Oyrtospirifer, and others), and the associated 

corals are commonly Pachyphyllum and Thamrnopora. 

These assemblages are discussed on pages 65 and 66. 

Coquina-type deposits are common in many stratigraphic sections. They consist entirely or predominantly of one species, but their aspect and composition 

are rather variable from place to place. Coquinas consisting entirely of shells of Theodossia cf. T. hungerfordi are common in and near the upper Canyon Creek 

area (section 8, subunit 26; section 12, subunit 44; section 13, subunit 24; section 16, subunit 16). These occurrences are tLt different levels within the uppermost 

80 feet or so of the upper unit. Such coquinas, therefore, seein to be lenticular. Figure 27 shows a typical 

example. Although many shells have the position convex side down, the orientation is partly random; many 

shells have the opposite position, convex side up; and 

others occupy intermediate attitudes. In this type of 

FIGURE 24.--Thanatocoenosis of a massive stromatoporoid (right) nnd a Disphyllum colony (center), surrounded by growth of Syringopora, in 

dolomitic limestone. Section 30, Diamond Point, top of upper unit of Jerome Member (subunit 46). X 0.78. USNM 138890. 
60 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

coquma, the ventral and dorsal valves of almost all 

shells have become separated. 

In the Roosevelt area coquinas of Schizophoria iowensis occur with disarticulated valves more or less in random orientation; most of them have the convex side 

facing either up or down, though some have intermediate positions (fig. 28). 

Coquinas of the type discussed are true taphocoenoses, 

although the excellent preservation of the shells and 

their random attitude in the rock suggests that no prolonged transportation has taken place. A feature of 

these taphocoenoses is that within each the fossils are 

all of comparable size. Because they came to rest and 

were buried at no great distance from their original 

biotope and because, as indicated by the preservation of 

the shells, only weak currents having little winnowing 

effect were active, coquina deposits of this type are 

probably derived from shell banks whose composition 

did not differ much from that of the coquinas. 

A second type of coquina is illustrated by a sample 

from the top of section 18 (fig. 29); it contains a mixed 

assemblage in which Atrypa and Spimatrypa predomiFIGURE 25.- Thanatocoenosis of Disphyllum sp. and Aulopora sp., intricately intergrown, in dolomitic limestone. Section 27, Tonto and 

Horton Creeks, near top of upper unit of Jerome Member (subunit 19). X 0.51. USNM 138892. 
ROCKS OF THE MARTIN FORMATION 61 

nate, Oyrtospirifer is third in abundance, and scattered [ 

specimens of Schizophoria and a rare Thammopora occur. Individuals are tightly to loosely packed. Both 

valves of many shells are hanging together, and the 

valves of some specimens, firmly connected at the hinge, 

are slightly agape (fig. 30A and 0). The relative position of the valves must have been acquired soon after 

de.·tth, as is the rule in pelecypods. In brachiopods, 

because of different construction of their hinge apparatus, this condition is less easily understood. In fact, 

Shrock and Twenhofel ( 1953, p. 275) stated that "the 

shells of recently dead brrrchiopods and of many fossil 

forms are likely to be elosed unless the valves "·ere 

actually disarticulated or torn apart. This situation is 

the reverse from that found in pelecypods* * *." However, gaping articulated brachiopod shells, like gaping 

articulated pelecypod shells, indicate little transportation and rapid burial, and the association discussed here 

from section 18, therefore, may be assumed to be a true 

thanatocoenosis. The brachiopods preserved in this 

FIGURE ~1 hamnopora colonies, not in growth position, in calcitic 

dolomite. Section 32, East Verde River, upper part of upper unit of 

Jerome Member. X 1. USNM 138893. 

rock represent a natural community whose biotope was 

the place in which it became fossilized. 

Another example of a thanatocoenotic assemblage 

occurs in the top subunit of section 1 (Sawmill) and consists of large numbers of individual brachiopods representing several species of Atrypa. Among them are 

also articulated, gaping shells (fig. 30B and D). 

A coquina of unique composition, near the top of section 38 (Limestone Hills), consists entirely of tightly 

packed specimens of Oamarotoechia sp., Oranaena(?) 

sp., and some Oyrtospirifer sp. (fig. 31). The shells are 

mostly delicate and articulated, and the valves are 

closed. No appreciable transportation could have taken 

place, and this rock undoubtedly represents a shell bank 

in a state very close to its original composition and goometrical arrangement. 

Much quantitative work remains to be done on associations of this type, which occur scattered throughout the upper part of the upper unit of the Jerome Member in the entire area investigated. 

In impure carbonate rocks and in calcareous and dolomitic siltstones, brachiopod species are fewer than in 

purer carbonate rocks; in places atrypids alone are present-for example, in the silty facies of the upper unit in 

sections 2 (Black River) and 35 (Pinal Creek). At 

Pinal Creek atrypids are associated with Devonoproductus, which elsewhere is exceedingly rare. At this 

locality, most of the valves of both the atrypids and the 

productids are in articulated, closed position, indicating 

that their biotope was the silty, muddy bottom that later 

formed the rock in which the fossils are enclosed. 

A comparison of the habitats of important brachiopod genera in the Jerome Member with those of the 

same genera in Middle Devonian beds of eastern and 

central United States, as described by Cooper (1957, p. 

270), discloses some significant differences. For example, Atrypa is characterized by Cooper as a "lover 

of limy sediments" in eastern America. While this is 

true for most occurrences of the genus in the Jerome 

Atrypa is also among the few brachiopods that 

thrived in very silty carbonate mud. Schizophoria, on 

the other hand, in the Jerome is almost restricted to very 

pure carbonate rocks, whereas in eastern America, according to Cooper, it is uncommon in limestones. The 

Spirifers, too, are found mainly in carbonate rocks in 

Arizona, whereas, according to Cooper, they occur in all 

sediments execpt black shales in the East. Cooper's observations were made over a very much larger area than 

the present study a.rea and are perhaps of more general 

validity, but observations in the Jerome show that local 

environmental influences may produce local paleontological facies patterns. 
62 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

Mollusca 

Fossil mollusca are much less numerous and varied 

than the brachiopods in the Jerome Member as a whole. 

A few unidentifiable gastropod remains occur at scattered localities. The only well-preserved . molluscan 

fauna is found in the upper part of the upper unit on 

Verde River at Sycamore Creek (section 43). It was 

described by Stoyanow (1949) and consists of the 

following species: 

Pelecypods : 

Congeriomorpha andntsovi Stoyanow 

T1tsayana cibola Stoyanow 

Gastropods: 

Aglaeoglypta maera (Conrad) 

Arizonella allecta Stoyanow 

Arastra torquata Stoyanow 

This assemblage has not been recognized anywhere else, 

although Arizonella has been doubtfully identified from 

section 9, subunit 14. The mollusks are associated 

with the corals Bre'viphyllum( n sp. and Hemagonaria 

sp., none of which were in growth position. This association is somewhat puzzling. The two pelecypods, 

both new genera described by Stoyanow, are as yet 

known only from the type locality. Both clearly have 

myalinid affinities. They have thick hinges and heavy 

hinge features such as are possessed more commonly by 

forms living near reefs or in turbulent water; Eumegalodon is a well-known example from such environments 

in Devonian rocks. The Verde River fauna, however, 

occurs in saccharoidal dolomite, which most probably 

represents dolomitized fine-grained limestone. Paleoecological evaluation of this fauna must await further 

study of its distribution. 

Poorly preserved pelecypods were found in sandstone 

of the upper member of the Jerome Member at Mormon 

Tank (section 47). They appear to be pteriids, possibly representing Limoptera or some related genus. No 

forms similar to these have so far been reported from 

Devonian rocks anywhere in Arizona. 

Cephalopods are exceedingly rare. One unidentifiable fragment of a straight nautiloid was seen near the 

top of section 9 (Oak Creek Farm Road), and a tiny 

specimen of an unidentifiable goniatite was found in a 

rock from section 2 (Black River), subunit 17 (pl. 18, 

fig. 2). 

Pteropods had not previously been reported from 

Devonian rocks in western Arizona. Shells, probably 

FIGURE 27.- Coquinn composed of silicified shells of Theodossia cf. T . hungerfordi (Hnll) and Oyrtospirifer sp. cemented by cnlcltlc dolomite. 

Section 12, Lost T ank Canyon, upper part of upper unit of Jerome Member, subunit 44. X 1.1. USNM 138894. 
ROCKS OF THE MARTIN FORMATION 63 

belonging to Styliolina, " ·ere recognized in a few thin 

sections of aphanitic limestone (pl. 13, fig. 1), but no 

readily identifiable specimens were found. 

Ostracoda 

Ostracode remains are not uncommon in aphanitic 

limestones, where their shells are seen in cross section, 

but the only identifiable assemblage comes from subunit 22 of section 32 (East Verde River) in the top of 

the aphanitic limestone unit. According to Jean Berdlm lmd I. G. Sohn ('Hitten commun. 1960) these ostracodes belong to the genus Hypotetra,qona, which has 

a range from Middle Devonian to Permian. Further 

intensive search in the aphanitic limestone facies both 

of the aphanitic dolomite unit and of the upper unit 

should yield more diversified faunas. 

Echinodermata 

Crinoid ossicles, mostly columnals, occur in many 

limestones and dolomites, although rarely in sufficiently 

large numbers to justify calling them crinoidal limestones or dolomites. Crinoids apparently were a rather 

subordinate group in the biotas of the Jerome Member. 

Echinoid spines were found in aphanitic limestones 

of subunit 18, section 38 (Limestone Hills), near the 

base of the upper unit (pl. 8, fig. 1). The only recogniza:ble rema.ins are sma.ll spines, less than 0.5 mm thick. 

They consist of radially oriented "·edge-shaped calcitic 

elements having uniform crystallographic orientation. 

Devonirtn echinoids a,re rare; none have previously been 

reported from Devonian rocks in Arizona. The preservation of the specimens is insufficient for generic 

identification. 

Conodonts 

The only conodonts so far recorded from the Jerome 

Member are in section 43, subunit 26, where they occur 

only 2 feet above a layer containing the unique molluscan fauna discussed above. It should be emphasized 

FIGURE 28.--Coqu!na composed entirely of silicified shells of Schizophorin i owensis (Hall) cemented by calcitic dolomite. Upper part of 

upper unit of Jerome Member, northwest of Theodore Roosevelt Dam. X 0.84. USNM 138895. 
64 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

that the present investigations did not include a study 

of the conodonts, but ultimately the rocks of the Jerome 

Member may yield a good conodont fauna. 

Fishes 

Fragmen.ts of bony plates of armored fishes occur in 

many places and at different horizons. However, they 

are generally too incomplete to be identified, and no 

identifiable fish remains were obtained in the course of 

the present investigations. 

Fish plates, or impressions of them, occur in both 

sandstones and cai'honat:e rocks. In the upper unit they 

are perhaps more common in limestones and dolomites 

than in sandstones. 

At ·webber Creek (section 31) fish remains are 

abundant in a silty fine-grained dolomite (subunit 20), 

a few feet above the base of the upper unit. They were 

also observed in dolomites and sandy dolomites at 

Jerome (section 41, subunit 22), Limestone Hills (section 38, subunit 21), Theodore Roosevelt Dam (section 

3(-i, subunit 31), Windy Hill (section 37, subunit 18), 

Pinal Creek (section 35, subunit 10), and elsewhere. 

In nearshore deposits fish remains seem to prevail 

in the basal terrigenous deposits, whereas among strata 

formed farther out from the coast, they are more common in carbonate rocks. Their fragmentary nature 

seems to indicate either that they were transported long 

distances or perhaps that they are the remains of smaller 

fishes that were the prey of larger ones such as Dirnichthys. Presence of Dinichthys in the Jerome Member 

at Elden Mountain was first noted by Stoyanow (1936, 

p. 502) and later confirmed by Hussakof ( 1942), who 

described bvo species which he left unnamed. So far, 

however, no remains attributable to Dirnichthys have 

been recorded from any other locality in the Jerome. 

The Elden Mountain fish fauna as described by Hussakof is listed on page 44. 

FIGURE 29.-Top view of bedding plane of limestone containing a silicified taphocoenotic assemblage of Schizophoria cf. S. iowensis (Hall), 

Atrypa cle r oniana var. bentonensis Stainbrook, Spinatrypa cf. S. rotunda Stainbrook, Cyrtospirijer whitneyi (Hall), and scattered 

Thamnopora sp. Section 18, south of Turkey Peak, top of upper unit of Jerome Member, subunit 21. X 0.95. 
ROCKS OF THE MARTIN FORMATION 65 

Calclspheres 

Ca.lcipheres, here regarded as of uncertain taxonomic 

position, are very abundant in aphanitic and finely 

c(ystalline limestones; they occur in some limestones in 

such quantity as to be almost rock forming. (See pls. 

15-21.) In dolomitized limes( ones their forms are commonly obliterated, although "ghost" structures are seen 

in some aphanitic dolomites. Calcispheres, whatever 

their nature and affinities, contributed in an important 

mty lo the sedimentation of lime muds of (·he upper unil 

of the Jerome Member and probably formed the bulk 

of its original sediment before dolomitization. 

Mixed assemblages 

The foregoing discussion has emphasized the autecology of indi,·idual groups and their relations to characteristic lithologies. The Jerome fauna has been 

shown to consist of as much as 80 species; not all of 

c 

D 

them, however, are yet represented by material sufficiently well preserved to permit their formal descriptions. 

The following paragraphs present observations on the 

synecology of some of the more important groups. 

Data on the occurrence and general composition of fossil 

assemblages in the stratigraphic sections are presented 

in easily comprehensible nmnner in cross sections A-A' 

to!-!' ( pls. 28-31). 

The most common and important associations of 

megafossils are those of brachiopods and corals. These 

are extremely common at or near the top of the Jerome 

Member where they occur in limestones or dolomitic 

limestones. The assemLlages vary somewhat in composition. Among the brachiopods, atrypids predominate almost everywhere. Associated with them may be 

spiriferids- especially Cyrtospirif er, Platyrachella, 

Tenticospirifer, and Brachythyrina--whereas TheodosF IG URE 30.-Articula ted gaping brachiopod shells as inrlicators of rupi<l burial under quiet-water conditions, and Rhizocora!limn and other 

burrows. X 1. A anq C, Atrypa devoniana var_ bentonensis Stainbrook. Section 1, Sawm_ill, subunit 8. USNM 138897. B and D 

Spinat1·ypa cf. rotunda Stainbrook. Section 18, south of Turkey Peak, subunit 21. USNI\1 138898. E, Rhizocoral!iu1n and other burrows 

in uppermost shale of Jerome Member (subunit 3,1 of section 3). Flying V Canyon, rouucut of U.S. Highway 60. 
66 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

FIGURE 31.- Coquina of silicified shells consisting mainly of Camarotoechia sp. and Oranaena( ?) sp. and containing very little dolomitic 

cement, which has been dissolved. Section 38, Limestone Hills, top of 

upper unit of Jerome Member. subunit 34. X 0.50. USNM 138896. 

sia tends to be restricted to coquinas. (See page 59.) 

No typical brachiopod -coral associations ever occur with 

atrypids, however. Brachiopods may be associated 

either with tabulate corals only- as in sections 1, 7, 9, 10, 

18, 28, 29, and 30, where the predominant associated corals are Thamnopora and Auloporar-or with rugose corals only-as in sections 8, 9, 32, and 38, where the Rugosa 

are predominantly Pachyphyllum and Hexagonaria; 

they may be also associated with both tabulate and 

rugose corals-as in sections 7 and 43. Any one of these 

types of associations is likely to be found either at the 

very top of the Jerome or at least within the uppermost 

100 feet. 

The fossils in these associations are everywhere well 

preserved. Many of the corals are in a growth position; 

brachiopod shells having articulated but gaping valves 

occur, as described on page 61. In general, therefore, such fossil associations are either thanatocoenoses 

or they represent only very slightly transported taphocoenoses. 

The biostromes that occur in the upper half of the 

upper unit of the Jerome Member also are thanatocoenotic assemblages. Their bulk is made up of masJ 

sive stromatoporoids, which are everywhere associated 

with varying proportions of corals. By far the commonest type of association consists of stromatoporoids 

and tabulate corals, especially the genera Thamnopora 

and Alveolites. Both these genera contributed to the 

buildup of many biostromal limestones. 

Among rugose corals occupying the biostromal biotope, Pachyphyllum is most abundant. H exagonaria 

also occurs here but tends to be more commonly associated with brachiopod faunas. 

In some biostromes all three groups-stromatoporoids, tabulate and rugose corals-are represented, but 

such occurrences are comparatively rare. (See sections 

8, subunit 22; 10, subunit 2; 13, subunit 17.) 

N onbiostromal coral associations are also found and 

may, in places, have subordinate numbers of stromatoporoids. They occur mostly in calcite dolomite not far 

below the top of the formation. (See sections 7, subunit 3; 16, subunit 19; and 29, subunit 16.) Coral 

colonies occur mostly in growth position and are scattered. 

Small ostracodes and calcispheres form an important 

and very uniform taphocoenotic association of a very 

different type of which many examples are known from 

the upper part of the aphanitic dolomite unit and the 

lower part of the upper unit. This association is very 

characteristic of aphanitic and very fine grained limestone. The possible role of the calcispheres in the formation of some limestones of this type is discussed on 

page 82. In addition to ostracodes, other accessory 

fossils found in the assemblage are tintinnids(~), pteropods, and scattered crinoid fragments, and many of the 

rocks contain large amounts of unidentifiable fossil 

debris. Limestone bearing the ostracode and calcisphere associations is widespread. (See sections 8, 9, 

17, 30, 31, 32, and 34.) Occurrences of calcispheres 

alone, without associated ostracodes and other fossils, 

are even more widespread. 

Trans and burrows 

Trails and burrows are found rarely in the a;phanitic 

dolomite member and more commonly in the upper unit 

of the Jerome Member. 

Simple, slightly sinuous trails occur in the clayey interbeds of the lower part of the aphanitic dolomite unit, 

where they are difficult to find and to study. 

In the upper unit, trails and burrows of various types 

occur. Straight intersecting trails as much as 4 inches 

wide occur in shale layers, and in fresh outcrops their 

casts may be well preserved on the underside of overlying sandstone or dolomite beds (fig. 22). 

The uppermost shale subunit of the upper unit on 

the Salt River shows evidence of intensive burrowing by 

different types of sediment feeders. The more or less 

horizontal undulating burrows of varying thickness, 

some of them having faint scratch marks, are commonest. More rarely, Rhizocorallium is found (fig. 30). 

These are U-'burrows of the U-in-U type, which were 

constructed parallel to the bedding plane and are as 
ROCKS OF THE MARTIN FORMATION 67 

much as 8.5 cn1 wide and probably more than 10 em 

long. 

Richter ( 1926) and Seilacher ( 1958) showed that the 

ani1nals that constructed the Rhizooo11alliu.1n type of 

burrmvs must have been plankton feeders· therefore ' ' the burrows indicate a n1arine environment because sessile plankton feeders cannot exist under stagnant lacustrine conditions. 

The upper shale unit of the upper unit in the Salt 

River area, thus, indicates a 1nuddy bottom under 

marine conditions, ·where the mud below the sedimentwater interface was inhabited by large numbers of sediment and plankton feeders that continuously reworked 

and destratified the sediment. 

745-106- 0--64----4 

SOME GROSS LITHOLOGICAL FEATURES OF THE 

JEROME MEMBER 

RELATIONSHIPS BETWEEN DOLOMITIZATION, INSOLUBLE 

RESIDUE, AND TOTAL CARBONATE CONTENT 

Some significant facts about the gross lithology of the 

carbonate rocks of the Jerome Member are shown in 

figure 82. The diagrams represent cha.racteristic, 

widely spaced stratigraphic sections; the three units are 

complete in all but one section (No. 34). On the diagrams the MgO percentage of total carbonate has been 

plotted against total carbonate percentage of the rock. 

To the value for total carbonate, 2-3 percent of other 

solubles should be added in order to obtain a more 

accurate percentage of HCl insolubles. 
68 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

Section 8 

Canyon Creek 100,-----,-,----.-,------------~~~~~~~------------------~~~ I "x: '\, 

.!:: 

i8o 

e 

QJ 

~ 70 0 

-e 

ro 

u 

I I ; I 

I I I X 

I I I 

I I 1' 

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 

1', 

I 

I 

I 

I 

I 

I 

I 

50 Limestone[ Dolomitic limestone 1 Calcitic dolomite 1 Dolomite 

0 2.1 10.8 19.5 21.6 

MgO percent of total carbonate 

Section 34 

100 ,_-----,--------------------~T_on_t~o_N __ at~u~r~a_I~B_ri~d~ge~------------

..... 

c 

~ 90 Q3 

Q. 

.!:: 

i8o 

e 

.!:: 

QJ 

~ 70 0 

-e 

ro 

u 

-ro 60 0 

I-

: X I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

X X 

'xJ 

X"" I' 

I X 

xl x 

I 

I, XX I 

50 LL_im_e_s_to_n_eL_ _______ D_o_lo_m_,_ti_c_li_m_e_st_o_n_e ______ ~~------~C~a~lc~it~ic~d~o~lo~m~i~te~------~~~~ 

100 

i8o 

e 

QJ 

~ 70 0 

-e 

ro 

u 

] 60 0 

I0 2.1 

I 

I 

I 

I 

I 

I 

I 

I 

10.8 

MgO percent of total carbonate 

Section 2 

Black River ------- ~------------------

X 

19.5 21.6 

I X X 

I xl 

I I 

I i 

I I 

I I 

I I 

I I 

50 LL_im_e_s_to_n_el_ _______ D_o_lo_m_i_tic~l~im~e~s_to_n~e ________ L_ ______ ~C~a~lc~it~ic~d~o~lo~m~i~te~------~~D~o~lo~m~i~te~ 

0 2.1 10.8 19.5 21.6 

MgO percent of total carbonate 

FIGURE 32.--MgO percent of total carbonate plotted against total carbonate percent of rock for samples from six typical sections 
ROCKS OF THE MARTIN FORMATION 

Section 4 

100 ~--~-----------S_a_lt_River, Asbestos mine 

Dolomitic limestone Calcitic dolomite 

10.8 

MgO percent of total carbonate 

Section 30 

Diamond Point 

I xx 'lex 

I 'lex~ 

I \x 

I X I X 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

xDolomite 

19.5 21.6 

100 I xl 

I 

I X X 

...... 

c I 

~ 90 I Q> 

Cl. I c I 

i8o I 

e I 

.!: I Q> I ~ 70 I 0 

-e I ro I (J 

] 60 I 0 

1- I 

I Limestone 50 

0 2.1 

Dolomitic limestone 

I 

I X 

I 

I 

I 

I 

10.8 

Calcitic dolomite 

MgO percent of total carbonate 

Section 41 

X I 

I 

I 

xl,x X 

I 

,xi 

I 

I 

I 

I 

I 

I X 

I 

I 

X 

X 

Dolomite 

19.5 21.6 

Jerome 100r-----~~-----------------------~------------------------~~----~ 

II X X.~ 

...... 

c 

~ 90 

Qj 

Cl. 

.!: 

i 80 

e 

.!: 

Q> 

~70 0 

.0 

ro 

(J 

-ro 60 

0 

1-

I I X Y' 

I I I 'x j :~ I I X I X X 

I I I~ X 

I I I X 

I I I xxx 

I I I 

I I I 

I I I' 

I I I 

I I I 

I I I 

I I 

I I 

I 

50 LimestonE!j Dolomitic limestone I I 

1 Calcitic dolomite 1 Dolomite 

0 2.1 10.8 19.5 21.6 

MgO percent of total carbonate 

of the Jerome Member. The noncarbonate component comprises siliceous-detrital material ranging in grain size from sand to clay. 

69 
70 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

The following important facts can be read from the 

diagrams: ( 1) the predominating rock type is a dolomite containing less than 20 percent insolubles; (2) 

limestones and slightly dolomitic limestones tend to have 

less than 10 percent insolubles; and (3) intermediate 

rock types-highly dolomitic limestones and highly 

calcitic dolomites-are rare, and values for most calcitic dolomites are clustered close to those for the lower 

limit of dolomite (19.5 percent MgO). 

Almost all the carbonate rocks at the typical section 

of the Jerome Member are pure dolomites containing 

less than 20 percent insolubles, and of these n1ost contain less than 10 percent insolubles. The carbonate 

rocks at section 4 on the Salt Rive,r are very similar to 

those at the typical section ; the sections differ only 

in the presence of one pure limestone and one very inlpure dolomite subunit at section 4. All other rocks are 

dolomites containing less than 20 percent insolubles. 

The Black River section (No.2) has more intermediate rock types (very dolomitic limestones and very calcitic dolomites) than do any of the other sections. 

Here, 6 out of 26 subunits are composed of rocks of this 

type. 

Canyon Creek (section 8) is another typical section 

in which intermediate carbonate types are lacking. At 

Diamond Point (section 30), nearly half the dolomitBs 

have more than 20 percent insolubles, but as indicated 

in plate 22, almost all the impure dolomites a.re found 

in the upper unit. 

The proximity of Tonto Natural Bridge (section 34) 

to Pine Island, a short distance to the north, is indicated by the high percentage of dolomites containing 

more than 20 percent impurities. The dolomites contrast strangely with a small cluster of very pure limestones and very slightly dolomitic limestones that are 

scattered throughout the section. The gross pattern 

of dolomitization in this section differs somewhat from 

that in other localities, because most of the dolomites 

have less than 19.5 percent MgO and must be classed 

as slightly calcitic dolomites. 

The foregoing discussion, as well as further study of 

the curves for total carbonate and ~fgO percentages of 

several additional sections (pl. 22), shows no close correlation between the degree of dolomitization and the 

insoluble content, except that almost all limestones and 

slightly calcitic dolomites have less than 10 percent insolubles, whereas dolomites, at least in places, contain a 

much wider range of in1purities. A distinctly greater 

proportion of impure than pure calcimn carbonate 

rocks are dolomitized. However, the large nun1ber of 

fairly pure dolomite excludes any generalizations. 

Rather surprisingly, a crude positive correlation seems 

to exist between total carbonate content of a rock and 

its MgO percentage; pure carbonate rocks are generally 

more highly dolomitized than impure ones. However, a 

more detailed examina,tion indicates that the relations 

are not simple. 

For example, at the typical section of the Jerome 

Member (pl. 23), all but one of the dolomites contain 

more than 19.5 percent MgO. A general parallelism 

between the curves indicating total carbonate content 

and those indicating MgO percentage exists for values 

of rocks throughout a considerable part of section 41, 

from ,subunits 4-31. Notable ex~eptions are for values 

of samples from subunits 7 and 27. In marked contrast are the curves of the values for the uppermost 

part of the section-subunits 32-37. Here the correlation is reversed-lower total carbonate corresponds to 

high MgO percentages, and vice versa. Interestingly, 

this reversal of the carbonate-MgO relations coincides 

with one complete insoluble residue cycle-cycle 9. 

These cycles are discussed on pages 71 and 72. 

Other sections in which total carbonate content and 

MgO percentage show a rough positive correlation are 

sections 4 (Salt River asbestos mine), 18 (Turkey 

Peak), 19 (Christopher Mountain Ridge), 26 (Doubtful Creek), and 36 (Theodore Roosevelt Da1n) (pis. 22 

and 23). In all these sections, dolomite dominates almost or entirely to the exclusion of limestone or even 

calcitic dolomite. In sections where all three units of 

the Jerome Member are present, the parallelism between the trend of the total carbonate content and the 

MgO content is generally somewhat more pronounced 

for values from the lower two units, whereas, in the 

upper unit this trend is reversed in many places; sections 4 (Salt River asbestos mine) and 41 (Jerome) 

indicate these relations for the three units. 

Where the upper unit is more or less pure dolomite, 

the conformity of the two concentrations is generally 

very great, as indicated, for example, by sections 18 

(Turkey Peak) and 26 (Doubtful Creek). Detailed 

comparison of the concentrations reve,als reversals of 

the trends in some subunits-for example, at the top of 

section 18. 

Where limestone subunits are present in a section, the 

relations are less consistent and trends are lost. Thus, 

in section 19 (Christopher Mountain Ridge), where two 

limestone beds occur near the top, the lower bed consists 

of 100 percent pure carbonate whereas the upper one has 

about 35 percent insolubles. Similar conditions exist 

in section 2 (Black River). 

In carbonate rocks of the Arbuckle Group of Late 

Cambrian and Early Ordovician age, Dunbar and 

Rodgers (1957, p. 223-224) found "a tendency for 

mixed rocks to be more impure." On the basis of analyses published by Decker and Merritt (1928), they 
ROCKS OF THE MARTIN FORMATION 71 

showed that limestones and high-magnesium-dolomites 

of the Arbuckle Group are relatively pure, whereas 

dolomitic li1nestones tend to have impurities ranging 

from 10 to 50 percent. Their results are comparable 

with those of Steidtmann (1917, p. 437), who, on the 

basis of analyses of 1,148 carbonate samples, concluded 

that intermediate limestone-dolomite rocks averaged 

higher in insoluble residues than either pure limestones 

or pure dolomites. Such relationships do not exist in 

the Devonian carbonate rocks of Arizona. 

On the other hand, on the basis of analyses published 

by Lesley ( 1879) for Lower Ordovician carbonate rocks 

of Pennsylvania, Fairbridge (1957, p. 155-156) and 

Dunbar and Rodgers (1957, p. 223) demonstrated that 

a positive correlation exists between the amount of impurities and the degree of dolomitization. Bisque and 

Lemish (1959) found the same relations in limestones 

of the Cedar Valley Limestone of Iowa. However, 

no pure dolomite occurs an1ong the samples used by 

Dunbar and Rodgers. Almost all the samples had less 

than 10 percent insolubles. The rocks studied by Bisque and Lemish were mostly low magnesium carbcnates 

containing a maximum of about 15 percent MgO. 

The same relations were noted and discussed also by 

Amsden (1960, p. 16-20) for carbonate rocks of the 

Silurian and Devonian Hunton Group of Oklahoma, 

although significant exceptions were mentioned. The 

rocks of the Hunton Group are even lower in magnesium than those studied by Bisque and Lemish. They 

are composed predominantly of limestone, magnesian 

limestone, and some slightly dolomitic limestone. Amsden suggested that the apparent correlation between 

HCl insolubles and magnesium content "might be explained under a hypothesis of 'secondary' origin by assuming that the argillaceous and silty calcilutites of the 

Hunton were more susceptible to dolomitization." 

Amsden believed that dolomitization occurred possibly 

at some time after the deposition of the Hunton Group 

and was possibly the type of "continental dolomitization" discussed by Fairbridge (1957, p. 153), although 

magnesium may have been introduced into the rock 

from the outside. 

In comparing the relations of insolubles to magnesium content in the Jerome Me1nber with the relations 

described by Dunbar and Rodgers, Bisque and Lemish, 

and Amsden, it must be remembered that in the Jerome 

dolomites high in magnesium content predominate. 

These relations may have a bearing on the problem of 

dolomitization (discussed on p. 85). 

A situation smnewhat similar to that in the Jerome 

Member seems to exist in the Lower Ordovician Ellenburger Group of Texas. Chemical composition and 

insoluble residues of 75 carbonate rock samples were 

analyzed by Goldich and Parmelee (1947) and, as Graf 

( 1960, p. 25) pointed out, no evident correlation between 

dolomite content and insoluble residue percentage exists 

in these rocks. Just as in the Jerome Member, the 

Ellenburger rocks studied by Goldich and Parmelee 

were predominantly either limestones or high-grade 

dolomites; only a few intermediate types were represented. 

INSOLUBLE-RESIDUE CYCLES IN CARBONATE SEQUENCES 

The insoluble residue of the carbonate rocks consists 

of sand, silt, and clay. Mechanieal analyses of the residues fron1 several stratigraphie sections have revealed 

a pronounced rhythmicity in grain size distribution 

(pl. 23). The pattern is most clearly seen in section 41 

(Jerome) , which represents a virtually pure carbonate 

facies. 

The section (pl. 23) can be divided into 10 divisions 

in such a manner that each division has as its base a 

rock unit containing a relatively coarse residue. Upward in each division, the residue is progressively finer, 

and near the top only clay, and locally some silt, is 

present. These divisions will be referred to as insoluble residue cycles. Thicknesses of individual cycles 

are remarkably uniform throughout the middle part of 

the section but are more variable in top and bottom 

parts of the formation (table 4). 

TABLE 4.-Thickness, in teet, of insoluble residue cycles in the 

Jerome Member (section 41) 

Oycle Thickness 

1 ------------------- 21 

2 ------------------- 19 

3 86 

4 ------------------- 45 

Oycle ThickneBB 

6 ------------------- 40 

'7 ------------------- 46 

8 ------------------- 9 

44 

96 

5 ------------------- 42 10 ------------------- 32 

Cycle 1 is not typically formed in this locality, but 

too little information is available on other localities to 

1nake valid comparisons. This cycle corresponds 

wholly or at least in major part to the fetid dolomite 

unit. 

All other cycles show a typical grading of insoluble 

residue from bottom to top. Most boundaries between 

cycles seem to coincide with boundaries of rock units as 

recognized in the field. However, it is not possible to 

be positive about this observation, because sampling 

was done with no thought of insoluble residue cycles. 

The rock succession of cycle 4 is interrupted halfway 

by a 2-foot sandstone bed, the so-called red marker bed. 

Its presence does not seem to influence the grading of 

the insolubles in this cycle; but here again, this conclusion might have been modified if samples had been taken 

closer to the sandstone bed. 

A comparison of the distribution of insoluble residue 

cycles with the total carbonate curve indicates a certain 
72 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

correlation between the quantity and the coarseness of 

residue-that is, the less pure the rock, the coarser the 

residue. (See cycles 4, 5, 8, ·and perhaps 9.) However, the relation is not clear cut. In cycle 4, for 

example, the three well-graded samples come fron1 

rocks containing very nearly equal amounts of insoluble 

residue~ and in cycle 2, the relationships are very 

irregular. 

A very clear correlation between the amount and the 

coarseness of insoluble residue exists in the two cycles 

found in the fragmenta,ry Elden Mountains section 

(section 44) (pl. 23). 

At the extreme opposite end of the area of investigation, information 9n residue cycles is available from 

sections 2 (Black River) and 4 (Salt River asbestos 

mine). The most complete sample coverage exists for 

section 4. Here the first cycle ( 1) seems to extend from 

the fetid dolomite unit into the base of the aphanitic 

dolomite unit. A sandstone bed (unit 9) very neatly 

divides the insoluble residue cycles 2 and 3. Conditions in cycle 5 are peculiar because of the great diversity of its rocks, which are composed of siltstone, dolomite, and limestone. In spite of interruptions by two 

thick siltstone beds and a ehange from dolomite to limestone upward in this cycle, the insoluble residues show 

good grading. In almost all cycles, some degree of 

correlation exists between the amount and the coarseness of residue. This correlation seems to be more 

consistent at Salt River than at ,Jerome. 

In section 2 (Black River) the first eycle seems to 

coincide with the fetid dolomite unit, although more 

information is needed to establish this relationship. It 

is followed by two good cycles in the aphanitic dolomite 

unit. The upper unit consists mostly of siltstone, but 

it has one good cycle in carbonate subunits 9, 10, and 11. 

The histograms depict relative amounts of residue 

having various size ranges within a sample. Variations of absolute amounts from sample to sample can 

be estimated by simultaneously comparing the histogram with the corresponding total-carbonate curve. 

The variations in absolute amounts of material within 

each individual size class are unimportant, because in 

every sample the power of the transporting ao-ent is • - b 

Indicated more by size of the largest detrital grains 

than by the quantity. This point has been well explained by Carozzi (1950, 1951) in the discussion of his 

concept of the elasticity index ('indice de clastiC'ite), 

which is determined by the maxin1mn diameter of 

detrital grains. Successive elasticity indices indicate 

variations in time of the power of the transporting 

agents without regard to factors of depth or distance 

from the coast ( Carozzi, 1950, p. 5) . 

· The cycles of graded insoluble residues should not 

be confused with graded bedding in limestones, as 

recently described by Kuenen and Ten Haaf (1956) and 

by Aubouin (1960), or with carbonate-rock cycles, as 

described from the Mississippian Redwall Limestone 

by McKee ( 1960). 

Lacking information on insoluble residue cycles from 

much more closely and evenly spaced control points, we 

cannot know conclusively if and how these cycles are 

correlative and whether their presence in a stratigraphic 

section reflects local conditions or the action of regional 

causative factors. 

Similar insoluable residue cycles seem to have been 

found by Wanless and others (1957) in Ordovician 

limestone sequences of Iowa, Illinois, and Indiana. The 

authors reported the presence of "nine cycles of abrupt 

coarsening of quartz grains, followed by gradual decrease in grain diameter" in four sections of the Platteville Limestone in these States. Wanless and others 

interpreted the cycles as indicating bathymetric 

changes, "suggesting widespread contemporaneous 

shifts in sea level." 

To consider tectonism to be a causative factor in the 

formation of the insoluble residue cycles in the Jerome 

Member would be open to doubt, mainly because the 

cycles are not clearly correlated with other lithologic 

changes and are not influenced by sporadic intercalations of other terrigenous sediments such as sandstone 

beds. Whereas the intercalation of a sandstone bed in 

a sequence of carbonate rocks indicates that some sudden change occurred in the conditions in the source area 

or in the transportation pattern of the sediments, the 

insoluble residue cycles seem to reflect major environmental changes. Such changes, therefore, are more 

likely to have operated in the source area than in the 

sedimentation medium, and the insoluble residue cycles, 

for instance, may have been caused by long-range cycles 

in precipitation. Such an hypothesis might help to explain the unequal thickness of the cycles in stratigraphic sections composed predominantly of carbonate 

rocks, which were deposited probably at a relatively 

uniform rate. 

LUSTER MOTTLING 

"Luster mottling" is a term that has long been applied to certajn calcareous sandstones in which the 

detrital quartz grains are enclosed in an aggregate of 

fairly large calcite crystals generally a centimeter or 

1nore in diameter. Such rocks are also variously referred to as "crystal sandstone" or "sand calcite"; they 

have been called "Fontainebleau sandstone" by Australian authors because luster mottling is characteristic 

of the Oligocene Fontainebleau Sandstone of the Paris 

basin (W oolnough and Son1erville, 1925, p. 81; Clarke, 

Prider, Teichert., 1955, p.165). 

One of the best discussions of this rock texture is by 

Sweeting ( 1925, p. 413-415) in his description of the 
ROCKS OF THE MARTIN FORMATION 73 

megascopic appearance and microscopic characteristics 

of the "Tilgate Stone," a calcareous "grit" of Cretaceo~ 

age occurring in Sussex. Sweeting stated that "the 

quartz occurs in closely packed minute fragments 

poikilitically enclosed in well defined areas of calcite 

which are optically continuous." Lapparent (1923, p. 

81) referred to the texture itself as "poecilitique." 

Luster mottling in calcareous sandstones is due to 

recrystallization of the calcareous matrix and is an end 

result of long continued grain growth of the calcite 

crystals. The term is here used also in describing rocks 

that consist of clusters of calcite or dolomite crystals 

having parallel optical orientation within each cluster 

but in which individual smaller crystals have retained 

their identity. Megascopically, the appearance of such 

rocks is the same as that of "crystal sandstone," because 

the light is reflected from the crystal clusters in the same 

manner as from one crystal surface. 

Among rocks of the Martin Formation, luster 

mottling is found not only in sandstones but also in 

limestones,. dolomites, and carbonates of intermediate 

type. The only previous reference to luster mottling 

in a carbonate rock seems to be by I\::hvorova ( 1958b, 

p. 263, pl. 30, fig. 4), who described this type of texture 

in a partly dedolomitized ( calcitized) dolomite. 

Typical calcite sandstone occurs in the upper unit of 

the Jerome Member (pl. 14, fig. 5). Quartz grains are 

embedded in a rather turbid variety of calcite, which 

is .arranged in units that have a somewhat irregular outline and are as much as a few centimeters in diameter; 

each calcite unit has uniform crystal continuity. 

The earbonate rocks having luster mottling are of 

several different types and compositions. Plate 14, 

figure 4, illustrates a slightly sandy carbonate roek in 

whieh opt.ieally continuous ealcite is arranged in large 

areas enclosing dolomite rhombohedra having random 

optical orientation. 

There is evidence that rocks of this type are in a 

state of dedolomitization. Although many dolomite 

rhombohedra have well-defined euhedral shapes, others 

have irregular outlines; the marginal parts of many 

seemingly euhedral dolomite erystals have been replaeed by ealcite and are in optieal eontinuity with the 

surrounding ealcite matrix, although the original outline of the dolomite crystal is still visible. 

Not all luster-mottled earbonate rocks are of the type 

just described, beeause luster mottling is also present in 

pure dolomites and in pure limestones. An example of 

luster mottling in a dolomite is illustrated in plate 10, 

figure 2. This rock consists of partly interpenetrating 

clusters of dolomite erystals that are in identical optieal 

orientation within each cluster. The same kind of texture in a limestone is shown in plate 14, figure 1. In 

the rock the individual crystals are much smaller than 

those in the dolomite; so each cluster eonsists of a much 

larger number of opt.ieally identically oriented crystals. 

The genesis of luster mottling in carbonate rocks is 

difficult to understand, especially why, since the 

mottling occurs at all, it is not more common. The 

occurrence of luster mottling as part of a dedolomitization pattern as well as in otherwise very ordinary 

dolomites and limestones indicates that more than one 

mode of origin in the rocks occurs. All such rocks 

apparently must have a complieated diagenetic history. 

SILICEOUS DETRITAL ROCKS 

The siliceous detrital roeks were not studied in detail 

Their regional distribution is discussed on pages 92 and 

93, but their petrography is briefly diseussed here. 

Most siliceous detrital roeks of the Jerome Member 

are fine-grained and very fine grained sandstones and 

siltstones (pl. 24) . The sandstones are generally clean 

well-sorted quartz sandstones (pl. 5, fig. 6) containing 

varying amounts of calcareous or dolomitic cement and 

having generally rounded to subrounded grains. Crossbedding is not conspicuous, but invertebrate tracks on 

bedding planes are relatively eommon. In all these 

features the sandstones of the Jerome contrast sharply 

with the rocks of the Beckers Butte. However, poorly 

sorted sandstones having subangular quartz grains also 

occur in the Jerome. Most of them are very calcareous, 

and the angularity of grains is at least partly the result 

of diagenetic processes. 

Two features of the sandstones of the Jerome Member deserving special attention are the eommon occurrenee of overgrowth on grains and the less common occurrence of sutured grain contacts. That these two phenomena are closely interrelated has been demonstrated 

by Siever (1959) and Thomson (1959), both of whom 

also discussed the geochemical implications. 

Good examples of overgrowth in sandstones of the 

Jerome Member are sho-wn on plate 12, figure 5, and 

sutured grain contacts are shown on plate 9, figure 5; 

plate 13, figure 5 ; and plate 15, figure 1. A combination 

of both phenomena is seen in the specimen illustrated on 

plate 10, figure 5. Solution of siliea may lead to very 

tightly packed grain aggregates in whieh all grains 

have lost their original form. Plate 15, figure 1, shows 

a sample in whieh the surface of a larger chert granule 

has been indented by the surrounding very smaH quartz 

grains, produeing a series of concavo-convex contacts. 

Grain contacts are either long, concavo-convex (in the 

terminology of Taylor, 1950), or sutured. Taylor 

( 1950) studied sandstones of Jurassic and Cretaceous 

age from the subsurface in Wyoming and found that. 

sutured contacts formed first in rocks found in wells at 

depths between 4,535 and 6,832 feet. No sutured contacts occurred in sandstones buried at depths of less than 
74 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

about 4,500 feet. Long grain contacts were most common in rock at a depth of about 4,535 feet and were 

progressively more scarce with increasing depth. 

The occurrence of sutured grain contacts in the sandstones of the Jerome Member follows no recognizable 

pattern. Such contacts are most common in the upper 

unit and are found in sandstones in both the lower and 

upper parts of that unit. As is discussed on page 81, 

none of these rocks were ever buried beneath more than 

about 3,000 feet of younger rocks. Sutured grain contacts, therefore, can form under pressures less than 

those found by Taylor. The erratic occurrence of 

sutured grain contacts is perhaps better understood in 

the light of observations by Heald (1956, p. 22-23), who 

suggested that the degree of pressure solution is positively related to the clay content of the matrix. 

It should be pointed out that descriptive terms for 

angularity of grains in sandstones of the type here 

described are meaningless because such terms refer to 

diagenetically acquired features of the grains. In many 

rocks the original shape of the grains at 'the time of 

deposition cannot be estimated. A clear distinction, 

therefore, should be made between sedimentary or primary grain contacts (the tangential contacts of Taylor) and diagenetic or secondary grain contacts which 

may be long, concavo-conve.x, or sutured. 

The upper unit of the Jerome Member, especially 

along the onlap belt and in the southeastern part of the 

study area, contains many very sandy carbonate rocks, 

including all gradations to highly calcareous or dolomitic sandstones. The rock illustrated in plate 14, 

figure 3, has the megascopic appearance of a fine-grained 

sandstone. Microscopically it has a matrix composed 

of very fine grained limestone and many aphanitic 

limestone clasts. Apparently, considerable autochthonous carbonate sedimentation occurred at this 

place while a considerable amount of fine-grained 

quartz sediment was being supplied from an outside 

source. 

Heavy-mineral analyses were obtained fron1 only a 

few samples of sandstone in the Jerome Member, chiefly 

to find possible differences in heavy-mineral content 

between these sandstones and those of the Beckers Butte 

Member. Two diagrams (fig. 33) show the occurrence 

and range of heavy minerals in the Beckers Butte and 

in sandstones of the Jerome in two typical stratigraphic 

sections. The percentage distribution of the five most 

common minerals also is shmvn on the left side of the 

diagrams. The only significant difference between the 

two sandstones is the more abundant tourmaline in the 

upper unit of the Jerome. This greater abundance may 

indicate a possible change of source area, a suggestion 

that is consistent with the paleogeographic evolution of 

the area. 

TEXTURE OF APHANITIC CARBONATE ROCKS 

INTRODUCTION 

Aphanitic carbonate rocks are important constituents 

of the Jerome Member. They are widely distributed 

in the aphanitic dolomite unit and, to a lesser extent, in 

the upper unit. Whereas aphanitic limestones have 

been studied by geologists in many parts of the world~ 

aphanitic dolomites have received little attention. Both 

rock types occur in the Jerome. Their megascopic appearance is either similar or identical; they look very 

much alike when examined with a petrographic microscope, but electron micrographs revealed significant 

textural differences between different types of rock. 

The nature and origin of aphanitic limestones and, 

to a lesser extent, of aphanitic dolomites have been much 

discussed in geological literature from Walther ( 1904) 

to Ha:dding (1958b), but the discussion remained largely 

speculative because little was known about the textures 

of these rocks. A variety of terms has been used to 

describe the rock type, as well as its texture. 

Cayeux (1935), as others before him, described the 

rock type as lithographic and sublithographic and its 

texture as cryptocrystalline. Barnes and others ( 1945) 

used the terms "lithographic" and "sublithographic" 

for such textures, and Strakhov ( 1958a) and other Russian authors used the term "pelitomorphic." The term 

"dense," once more popular for these rocks, now seems 

to be generally discredited (Rodgers, 1954, p. 230). 

Folk ( 1959) called the texture of aphanitic limestones 

microcrystalline and broke this category down into very 

finely crystalline (grain size 3.9-15.6 microns) and 

aphanocrystalline (grain size less than 3.9 microns). 

According to Tyrrell ( 1950) , a rock texture should 

be called microcrystalline if individual crystals can be 

distinguished only with the aid of an optical microscope; the term "cryptocrystalline" is used when individual crystals are too small to be distinguished under 

the microscope. The term "aphanocrystalline" of Folk, 

thus, is largely synonymous with cryptocrystalline as 

defined by earlier authors. 

l{indle ( 1923) proposed the term "vaughanite" for 

"fine-textured limestones * * * which contain few fossils * * * and break with a more or less conchoidal 

fracture." Although lithographic limestones are ineluded in this category, IGndle suggested that this term 

should not be used for the rock type as such because 

relatively few vaughanites meet the qualifications for 

lithographic limestones. Kindle suspected that vaughanites represent lithified calcareous muds of the type 

named "drewite" by Field ( 1919). 

Aphanitic limestones \vere, by implication, included 

in Grabau's (1913) hyclrocalcilutytes, or calcilutytes, 

now more commonly referred to as calcilutites. (See, 
Sample 

H56-3 

T56-262 

T56-261 

T56-244 

T56-243 

T56-242 

T56-241 0 

Sample 

T56-277 

T56-272 

T56-270 

H56-32 

H56-31 

Section 2 

Black River 

Section 8 

Canyon Creek 

ROCKS OF THE MARTIN FORMATION 

Q) 

E 

0 

Q; 

...., .... .,_ Q) 

O.o 

~ E c: Q) 

:::::1~ 

.... 

Q) 

a. 

a. 

:::l 

.... 

Q) 

.0 

E 

Q) 

~ 

Q) 

+" +" 

:::::1 

OJ 

~ Q) 

~ 

(.) 

Q) 

OJ 

Q) 

E 

e 

Q) 

...., .... .,_ Q) 0 .0 ~ E c: Q) 

:::::1 ~ .... 

Q) 

a. 

a. 

:::l 

.... 

Q) 

.0 

E 

Q) 

~ 

Q) 

+" +" 

:::::1 

OJ 

1/) 

.... 

Q) 

~ 

(.) 

Q) 

OJ 

EXPLANATION 

Ilmenite 

Leucoxene 

-

Zircon 

D 

Staurolite 

Muscovite 

Brookite 

Tourmaline 

Others 

FIGURE 33.-Distribution of heavy minerals in the sandstones of two typical sections of the Martin Formation. 

The left column of each diagram gives percentage distribution of the five most common minerals in successive 

samples; the right side represents the vertical range of all heavy minerals. 

75 
76 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

for example, Pettijohn, 1957, p. 408-409.) The "micrite" of Folk (1959) is by definition a limestone composed almost entirely of calcite grains 1-4 microns in 

diameter. It includes not only calcilutite and aphanitic 

limestone but also chalk. In the terminology of Hatch, 

Rastall, and Black (1938), aphanitic carbonate rocks 

are included in the categories of calcite mudstone and 

dolomite mudstone. 

Instead of employing terms that are either ill-defined 

( vaughanite), imply origin (calcilutite, pelitomorph) 

have technological use (lithographic), or are too broad 

in meaning (micrite), I refer to these rocks as aphanitic 

carbonate rocks, which if necessary may be further 

divided into aphanitic limestones, aphanitic dolomitic 

limestones, aphanitic calcitic dolomites, and aphanitic 

dolomites. The texture of aphanitic carbonate rocks 

can be called cryptocrystalline if the rocks are composed 

of crystals or crystalline particles of submicroscopic 

size. The particles are generally less than 5 microns in 

diameter. If the crystalline nature of the aggregate 

cannot be established with certainty, a more neutral term 

such as "ultra-fine-grained" is more appropriate. 

Megascopically, aphanitic limestones and dolomites 

have a homogeneous, smooth appearance, and under the 

hammer they break characteristically with a well-defined conchoidal fracture (fig. 13). They are typically 

thin to medium bedded, and their color ranges predominantly from dark medium to very light gray, although pinkish and orange hues also occur. Megafossils 

are generally scarce or absent. Among microfossils, 

ostracodes, Foraminifera, and calcispheres are locally 

present. Detrital quartz ranging in size from silt to 

medium grained locally forms a not insignificant constitutent (fig. 13). 

In most aphanitic carbonate rocks, no sedimentary 

structures are visible, but some rocks have recognizable 

pelletal, elotty, ealcarenitic, or brecciated structure. 

(See description of rocks of the aphanitic dolomite 

tmit) . These pellets, or clasts, also consist of aphanitic 

carbonate roc.k but generally differ slightly in shade of 

color. 

In conventional petrographic thin sections, an aphanitic rock, with the exception of the pelletal and clastic 

types, appears as a homogeneous film, suggestive of an 

isotropic substance. It shows no extinction between 

crossed nicols but appears somewhat darker than when 

viewed in un polarized light. Even high enlargement 

does not lead to a resolution of the image, because the 

average particle size of the rock is significantly smaller 

that the thickness of a standard petrographic thin section. At any one point on such a thin section, from 6-

60, or even 100, discrete particles of different crystallographic orientation may be superimposed. 

As to the origin of aphanitic carbonate rocks, Pettijohn (1957, p. 309) called this, with considerable justification, "a moot question." Aphanitic limestones have 

been variously interpreted as chemical precipitates, as 

results of the action of bacteria or algae, or as extremely finely clastic rocks, comparable to claystone 

that were transported either by water or by wind. 

This largely speculative discussion is not reviewed here. 

The origin of aphanitic dolomites has been discussed 

in recent Russian literature (Vishnyakov, 1951; Strakhov, 1958a; Rukhin, 1958; and others), where the tendency seems to be to regard them as primary precipitates. 

ELECTRON -MICROSCOPE INVESTIGATIONS 

To find new clues to the question of the origin of 

aphanitic carbonate rocks, their texture must be studied 

jn greater detail than is possible under the petrographic 

microscope; accordingly, several such rocks were 

studied 'vith an electron microscope. This tool has so 

far had little application in the study of carbonate 

rocks, apart from the work of l{abelac (1955) and of 

Seeliger (1956) ; these authors published two small 

electron micrographs of an Upper Jurassic "Splitterkalk" from South Germany. More recently, d' Albissin 

(1959) used electron micrographs to study the effects 

of deformation on aphanitic limestones in small-scale 

folds. 

The rocks selected here for study are aphanitic limestones, magnesian limestones, dolomitic limestones, very 

slightly calcitic dolomites, and dolomites, all of Devonian age, from various localities in central Arizona. 

John C. Hathaway of the U.S. Geological Survey prepared replicas of fresh rock surfaces for examination 

under the electron miscroscope and described the method 

used as follows (written commun., 1959) : 

Fragments of each sample were mounted on glass slides with 

acetate cement so that one fractured surface was parallel to the 

slide. The surfaces were then shadowed with platinum at 

angles from 30 to 60 degrees. Carbon was then evaporated 

vertically on the surface to form the replicas. Each surface 

was given a coat of wax to protect the carbon film during 

removal of the rock by solution in concentrated HOI. When 

effervescence ceased, the replicas were transferred to 48 percent 

HF and allowed to remain for at least 2 hours. The replicas 

were then washed in distilled water and the wax coating removed with xylene. 

Replicas taken from the following samples (table 5) 

were examined visually with the electron microscope 

and with the help of photographs made by John C. 

Hathaway. 

More than 50 photographs, including several stereopairs, were prepared from these samples in magnifications ranging from X 2,400 to X 32,000. 

All dolomites and slightly calcitic dolomites are from 

the aphanitic dolomite unit of the Jerome Member. 
ROCKS OF THE MARTIN FORMATION 77 

The samples of limestone, magnesian limestone, and 

dolomitic limestone come from relatively thin beds of 

the upper unit that are intercalated in predominantly 

dolomitic sequences. 

TABLE 5.-List of samples studied with the electron microscope 

[Amounts of MgO are given as percentages of total carbonate] 

Sample 

T56- 474 

-476 

-475 

H56-207 

T56-292 

-290 

H56-73 

-75 

- 27 

T57-444 

Locality MgO 

Section 34, Tonto Natural 

Bridge: Subunit 8___ ___ __ __ __ 0. 9 

Subunit 10_________ __ . 9 

Subunit 9_ __ ______ ___ 2. 7 

Section 30, Diamond Point, 1. 9 

subunit 19. 

Section 4, Salt River Asbestos mine: Upper part of subunit 

7. 

Upper part of subunit 6. 

Section 36, Theodore Roosevelt Dam: Lower part of subunit 

12. 

Middle part of subunit 12. 

Section 3, Flying V Canyon, upper part of subunit 8. 

Section 37, Windy Hill, 

subunit 1. 

18. 8 

19. 9 

20. 3 

19. 5 

20. 7 

20. 1 

Rock type 

Limestone. 

Do. 

Very slightly 

dolomitic 

limestone. 

Magnesian 

limestone. 

Very slightly 

calcitic 

dolomite. 

Dolomite. 

Do. 

Do. 

Do. 

Do. 

The textures of these rocks are best examined with 

the aid of stereopairs of electron photomicrographs at 

magnifications ranging from X 4-,000 to X 8,000 (pls. 25 

and 26). The size of the photographic prints is 

9% X 7% inches, which makes them suitable for examination under a mirror-type stereoscope such as used 

for viewing aerial photographs. The size of the area 

that canthus be scanned stereoscopically is about 60 X 49 

microns at X 4,000 and 30 X 25 microns at X 8,000. 

Higher magnification does not always lead to signif-icant 

refinement in resolution. At X 32,000 the area viewed 

under the sterescope is about 8 X 6 microns, and this 

magnification was used occasionally to obtain more 

minute details of the structure of individual grains or 

crystals. 

The different rock types listed in table 5 are indistinguishable megascopically, except for slight variations in color. Aphanitic dolomites of the type 

represe11ted by samples T56-290, H5H- 73, and H56-75 

were described as lithographic l i rnestones or dolomitic 

limestones by previous investigators in the area. 

All limestones consist of an aggregate of tightly 

packed grains that, as viewed stereoscopically, are 

rather irregular polyhedra ranging in diameter from 

0.4 to about 7.0 microns (pls. 25A and 26B). Measurements of grain diameters were taken along six traverses 

across a typical photograph of sample T56-474 at 

X 4,000. The aggregate length of these traverses was 

360 microns (a little more than one-third of a millimeter) along which 127 grains were measured. The 

count reveals a peak number of grains having diameters 

of about 1.6 rn icrons; the number of grains tapers off 

abruptly toward those having smaller diameters and 

more gradually toward those having larger diameters. 

The diameter of 56 percent of the grains counted was 

less than 2.5 microns, and that of only 12 percent was 

larger than 4.5 microns. It should be kept in mind, 

however, that the maximum diameter of all grains is 

not shom1 in the photograph. Parts of some grains are 

hidden by adjacent grains, and the diameter of the 

visible part of the grains is smaller than their greatest 

diameter. The count, therefore, is biased in favor of 

the small grains, and the true greatest number of grains 

may be those 2 microns in size. 6 On the other hand, 

examination of the stereopairs of photographs shows 

th'at entire grains as small as 0.2 microns, and possibly 

even smaller, exist. 

The surfaces of the irregularly polyhedral grains 

either are plane or are concavely or convexly curved. 

The surfaces of many grains are smooth, but those of 

others have irregularities in the form of tiny randomly 

distributed "cliffs," some of which are as short of 0.05 

microns and not more than 0.03 microns high, although 

most are .generally several times longer and somewhat 

higher. 

Grains on broken surfaces are composed of extremely 

thin lamellae that are 0.02-0.06 microns thick. Such 

surfaces have a characteristic terraced appearance (fig. 

34) that reveals the crystalline nature of the grains. 

The irregularities of some surfaces, described in the previous paragraph, apparently also reveal the lamellar 

texture of the grains and are due to a plucking action 

where part of the surface of the .grain was torn off as 

the rock was split. 

Some limestones grains, mostly those about 6 microns 

in diameter, tend to break along smooth fracture surfaces somewhat resembling the conchoidal fractures of 

the rock itself, although the size ratio between the two 

types of fracture may be on the order of 1: 10,000. 

The electron-microscopic texture of aphanitic 

dolomites differs from that of limestones. Dolomites 

also consist of an aggregate of polyhedral grains; but 

these tend to be bounded by flat regularly shaped planes, 

and many grains have a well-defined rhombohedral 

0 The problem of determining the true grain-size distribution from 

electron photomicrographs i~ similar to that of determining grain-size 

distribution of sandstones from thin sections. However, available statistical methods (see 111iinzer and Schneiderhiihn, 1953) could not be 

applied without modification because the true diameter of all particles 

that are fully exposed on the rock surface can be measured. Whereas 

in thin sections all measured cross sections are random, the cross sections 

measured In electron photomicrographs are only partly random. 
78 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

FIGURE 34.- Electron micrograph of subaphanltlc magnesian limestone. 

Sample H56-207, section 30, Diamond Point. X 5,000. 

shape (pis. 25B and 26A). Grain diameters are difficult to determine because in many areas the rock has 

a "massive" appearance where "grain size" is determined by spacing of cleavage planes. The smallest 

dolomite rhombohedron observed is about 0.1 micron 

in diameter. 

Viewed stereoscopically, the surface of an aphanitic 

dolomite appears to be more "rugged" than that of an 

aphanitic limestone because of the greater angularity 

of the grains and because the polyhedra tend to break 

along plane surfaces. 

Conchoidal fracture of individual grains is rare in 

dolomites, whereas lamellar structure is common (fig. 

35). The lamellae are of the same order of magnitude 

as those occurring in limestones-that is, they are between 0.02 and 0.06 microns thick-and the surface of 

some grains is densely pitted. 

On comparing the dolomites with the limestones, one 

must take into account that most dolomites contain 

some calcium carbonate and most limestones contain 

some dolomite. The rare grains having smoothly 

curved surfaces and apparently conchoidal fracture 

that are seen in dolomites, thus·, may be calcium carbonate particles; conversely, the rare grains having a 

well-formed lameHar structure that are seen in limestone may be particles of ( Ca,M:g) C03 • 

The texture of aphanitic limestone as well as of dolomite, as revealed by electron microgra.phy, is probably 

of diagenetic, not sedimentary, origin. The origin and 

diagenesis of these rocks are discussed on pages 81-84. 

DEPOSITIONAL ENVIRONMENT AND DIAGENETIC HISTORY OF THE CARBONATE FACIES OF THE JEROME 

MEMBER 

ROLE OF DIAGENESIS 

All sediment~try rocks are the products of, first, sedimentary and, second, diagenetic processes. To reconstruct the history of a rock, criteria must be recognized 

that allow us to trace the course of both processes, but 

this is not always possible. The rock properties that 

allow reconstruction of the sedimentary environment 

constitute the sedimentary facies (Teichert, 1958). 

Features from which the diagenetic history of a rock 

can be induced should, as far as possible, be excluded 

from the formal facies concept, or they should be clearly 

distinguished as diagenetic facies. For example, a rock 

that consists entirely of secondarily formed dolomite 

crystals has lost its sedimentary facies. Its sedimentary 

history and environment can no longer be accurately 

reconstructed from its texture and composition. 

The diagenetic history of a rock is determined by 

what may be called the diagenetic environment, and 

study of the diagenetic environment plays an important 

part in the interpretation of diagenetic history. Since 

the term "diagenesis" has acquired many meanings in 

the course of time, a brief historical digression is 

necessary. 

The term "diagenesis" (Diagenese )7 was coined by 

Gumbel ( 1868 p. 838) for proce3ses he believed to have 

been responsible for the formation of gneiss, which he 

regarded as a deposit formed in a hot sea. This use now 

has only historical interest. In 1888 Gumbel (p. 56, 334, 

380, 1056) upheld the original definition of diagenesis 

but included in it the discussion of processes that /are 

now generally called lithification. 

Diagenesis as a modern scientific concept stems :from 

Walther (1894), who defined it as (translated) "all 

those physical and chemical alterations which affect a 

rock after its deposition, excluding the effects of mountain pressure and volcanic heat." This definition did 

not specifically exclude weathering, but this exclusion 

has been genernJly understood. 

A slightly more precise and more restricted definition 

of diagenesis was given by Andree (1909; 1911, p. 73) 

(translated) : 

Diagenesis of sediments [comprises] those molecular and 

chemical rearrangements * * • which affect the sedimentary 

material under the influence of the sedimentation medium and, 

after emergence from this medium, of ordinary rock moisture 

or circulating vadose waters, unless these contain dissolved 

foreign matter (that is, matter derived from sources outside the 

sediment) . 

Andree thus regarded as diagenetic processes all 

alterations that begin immediately after the deposition 

of a sediment and that take place in a closed system, but 

he did not put any limitations on the size of such a 

closed system. Obviously, diagenesis begins when 

sedimentation is still in progress--that is, in a succes7 According to Hucke (1951) , the word is derived from Greek 

6u.-yt-yvop.at (diagignomai), to go through, to pass. According to Mur awski and Beringer (1957), its meaning Is 6ta 'Y<VE<n< (dia genesis) , 

after genesis. Both etymological Interpretations go back to the same 

roots. 
ROCKS OF THE MARTIN FORMATION 79 

sion of strata, diagenesis of the lower beds began earlier 

than that of the upper beds. How far does material 

have to migrate laterally before it can be identified as 

coming from "sources outside the sediment"~ This 

question has never been clarified, and establishment of 

definite standards is perhaps impossible. 

Although a full historical treatment of the concept of 

diagenesis is not intended, it should be pointed out that 

the term has long been accepted by German and other 

European geologists for all alterations that take place 

in a sediment from the moment of its deposition, through 

its conversion into rock, and in the rock itself, unless 

they are produced by addition of extraneous material, 

by weathering, or by those processes that are generally 

regarded as metamorphism. In this definition, material is generally not considered as extraneous if it is 

derived from rocks within one major and natural unit 

of sedimentary rocks-such as a sedimentary basinF IGURE 35.-Electron micrograph of aphanitic dolomite. Sample T56-290, section 4, Salt River. Well-formed dolomite rhombohedra in lower 

left; lamellar texture in upper half. X 39,000. 
80 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

or from a major tectonic tmit-such as a fault block 

or thrust sheet. 

Van Hise's (1904, p. 32) definition of metamorphism-"any change of constitution in any kind of 

rock"-includes all diagenetic processes after lithification. Other geologists, such as Hucke (1951), proposed 

to extend the scope of the definition of diagenesis to 

include weathering and metamorphism. However, 

most geologists found it useful to distinguish diagenesis 

that proceeds under conditions of "low" pressure and 

temperature from metamorphism that occurs under conditions of "high" pressure and temperature. 

Among geologists in the United States, a growing 

tendency in recent years has been to restrict use of the 

term "diagenesis" to late diagenetic processes and to 

refer to early diagenetic processes as lithification. (See 

Pettijohn, 1957, p. 648.) This usage is somewhat misleading because not all early diagenetic processes lead 

to lithification. Emery and Rittenberg (1952) and 

Russian authors (see Chilingar, 1958) showed that 

chemical properties of the unconsolidated sediment may 

change with increasing distance from the water-sediment interface. Sooner or later, lithification may set 

in, but lithification is only a special case of early diagenesiS. 

Recognizing this conflict in definition, Russian authors defined the early diagenetic processes in the unconsolidated sediments as syngenesis. For a summary, 

see Rukhin (1058, p. 226-227) . Syngenesis is followed 

by diagenesis, which, according to Rukhin, is characterWESTERN 

ized by those processes that transform the sediment into 

a rock. Diagenesis in this sense is thus at least partly 

synonymous with lithification as used in American literature, whereas syngenesis comprises the prelithification 

or early lithification processes. Russian authors also 

distinguish epigenesis, which comprises all processes 

that affect the finished rocks, including weathering and 

metamorphism. 

A comparison of the most common modern usages of 

diagenesis and related terms is given in figure 36. 

Unfortunately, the terms "synglmesis" and "epigenesis" have very definite and long-established meanings in 

igneous petrology and economic geology. Thus, 

Amstutz (1959) includes in syngenesis the sedimentation process itself. Epigenesis has long been understood to refer to all alterations affecting a rock, including those introduced by the addition of extraneous 

substances. 

There is, of course, complete gradation of all physical 

and chemical alterations and rearrangements that affect 

a sediment from the deposition of the first sedimentary 

particle until obliteration and removal of the rock by 

weathering or its complete remaking by metamorphism. 

If distinguishing and naming several more or less arbitrarily defined stages in this chain of processes is desired, the coining of new terms is to be preferred to 

inconsistent redefining of old ones. 

I propose to retain the term "diagenesis" in the traditional manner to apply to all physical and chemical 

alterations that take place within a body of sediments 

WEATHERING I 

EUROPEAN I DIAGENESIS 

/ I 

USAGE I"~ I METAMORPHISM I 

RECENT /I WEATHERING I 

AMERICAN I 

USAGE 

LITHIFICATION 1-- L DIAGENESIS 

I~ I METAMORPHISM I 

RECENT 

RUSSIAN l SYNGENESIS 1--1 DIAGENESIS 1--C EPIGENESIS I 

USAGE 

l''IGURE 36.-Comparlson of some current terminologies for diagenetic and r ela ted purposes. 
ROCKS OF THE MARTIN FORMATION 81 

as well as the sedimentary rocks derived from them, 

from the moment of its deposition until the onset of processes that are commonly attributed to metamorphism 

or weathering. 

Diagenetic processes vary widely in their results and 

the speed with which these results are attained. Some 

sediments, such as some clays and certain kinds of chalk, 

never became lithified. In other sediments, lithification 

may be accomplished in a season or a few years, and 

lithification and erosion (that is, wealil1ering) may be 

simultaneous or overlapping processes; examples are 

beach rock and sun-baked clay in dry river beds. Sujkowski ( 1958) recently listed several such occurrences. 

In general, only a loose differentiation between early, 

middle, and late diagenetic stages is possible; these categories may be named eodiagenesis, mesodiagenesis, and 

telodiagenesis,8 respectively. The boundaries between 

these stages are as fluid as those between diagenesis and 

metamorphism, and the succession and speed of events 

depends on the rock, the time, and the environment. 

Thus, lithification 1nay be eo-, meso-, or telodiagenetic, 

or it may not occur at all. Dolomitization may be eo-, 

meso-, or postdiagenetic. Processes generally labeled 

penecontemporaneous occur in the early phases of eodiagenesis. 

Definition of more precise limiting conditions of the 

diagenetic environment with regard to time and certain 

physical conditions (pressure and temperature) to 

which the Devonian rocks of central Arizona have been 

subjected will now be attempted. 

According to Mcl\:ee (1951, pl. 3, map C), the thickness of the combined Paleozoic rocks in the study area 

was between 3,000 and3,500 feet. These figures include 

from a few to more than 500 feet of rocks of Devonian 

and of Cambrian ( ~) age in various places. A former 

cover of about 1,500 feet of sediments of Triassic age 

should be added to this total (Mcl{ee and others, 1959, 

pl. 9, figs. 1 and 3). Post-Triassic rocks were either 

absent or negligible in the area. Thus, none of the Devonian rocks, apparently, were ever buried 1nore deeply 

than 5,000 feet, and the maximum depth of burial was 

in places considerably less than 4,000 feet. Thus, in the 

upper Tonto Creek and lT pper Salt River area, where 

the Mississippian Red wall Limestone is thin, maximum 

depth of burial of rocks at the top of the Devonian section was about 2,500 feet. 

Translated into terms of temperature and pressure, 

the extreme conditions to which some, but not all, rocks 

described in this report were exposed were 15°0 above 

prevailing surface temperatures and 300 atmospheres 

(or 4,500 pounds per square inch), respectively. 

8 Krotov (1952) introduced the term "telogenesis" in a somewhat 

similar sense for late diagenetic processes, but he restricted its application to special conditions prevailing in lakes and barred basins. 

The greatest pressure and temperature were reached 

in some parts of the area in the course of some 50-80 

million years between the Late Devonian and some time 

in the Permian Period and were maintained at an even 

level for another 150 million years or so until the Laramide orogeny; the orogeny uplifted and subsequently 

led to the erosion of much of the Devonian and younger 

Paleozoic rocks. Consequently the time span available 

for the action of diagenetic processes was about 200-250 

million years. 

Chemical and physical processes acting imperceptibly 

over such a long period of time cannot easily be attributed to neatly defined successive stages, and a determination of a particular time in which most diagenetic processes have taken plaee is difficult. Sujkowski 

(1958) pointed out that "diagenesis works in jumps 

and steps." In general, only the time sequence of diagenetic events can be determined. 

FETID AND APHANITIC DOLOMITE UNITS 

At the beginning of the deposition of the Jerome 

Member, the southwestern edge of the Defiance uplift 

was roughly parallel to and a few miles southwest of 

the present Mogollon Rim. To the southeast it lay 

proba;bly close to the present upper Salt River. A featureless plain that was at least 50 miles wide--but 

probably much wider-and at least 100 miles long and 

was mostly sandy but dotted with claypans in and 

around which a flora of psilophytes had taken root extended southwest of the edge of the uplift. 

A layer of lime mud rich in organic matter was deposited across the plain; the mud was compacted and 

dolomitized and is now represented by the lowermost 

unit of the Jerome Member-the fetid dolomite unit. 

The diagenetic history of this unit is discussed on page 

32, but the nature of sedimentation is considered further 

here. Since, as a rock unit today, the fetid unit averages about 20 feet in thickness, the original lime mud 

must have formed a fairly uniform layer between 30 and 

40 feet thick that covered the entire plain. Penetrating 

the lime mud were closely spaced thin layers of organic 

1natter derived frmn marine organisms that were probably mainly or entirely planktonic. The sedimentation 

area at this time was perhaps a large embayment into 

which plankton and algae drifted with the wind, but if 

so, the possible location of its southeastern and southwestern shores is not known. 

The preceding interpretation of the origin of the fetid 

unit is supported by the fact that the laminated dolomite rock has many characteristics of dolomites normally associated ·with evaporitic sediments ( Carozzi, 

1960, p. 436). Although no evaporites occur in the 

fetid dolomite unit, sedimentation may be assumed 
82 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

to have taken place under somewhat restricted 

conditions. 

The water in which the original sediments accumulated could not have been deep because the fetid dolomite unit only slightly transgresses the edge of the 

Defiance uplift; the edge of the unit lies only slightly 

northeast of the margin of distribution of the Beckers 

Butte Member. The depth at which deposition occurred could have been as much as the combined original 

thickness of the sediments of the aphanitic dolomite 

and fetid dolomite units-that is, possibly 250-300 

feet-but this thickness would certainly represent a 

maximum depth. Perhaps half this thickness is a more 

realistic estimate of the depth. 

We may assume, then, that the plain southwest of 

the Defiance uplift "\vas ultimately covered by 100-150 

feet of water, possibly in a large embayment. Accumulation of lime mud and organic matter proceeded below 

the turbulent zone, as is indicated by the generally undisturbed fine to ultrafine lamination of the beds and 

the scattered slump features. 

At the time of the deposition of the unit, only a 

small supply of terrigenous detrital material was available. Some terrigenous beds may have been deposited 

near the northeastern shore, but if such deposits existed, 

they are difficult or impossible to distinguish from the 

sandy facies of the overlying aphanitic dolomite unit. 

Almost all the original calcitic mud became dolomitized into very uniform fine- and even-grained dolomite and calcitic dolomite. The general succession of 

diagenetic processes in this rock is discussed on page 

32. Some aspects of diagenesis are reconsidered after 

the conditions of sedimentation of the aphanitic limestone unit are discussed in the following paragraphs. 

The contact between the fine-grained dark fetid dolomite of the fetid dolomite unit and the first aphanitic 

lighter colored beds of the aphanitic dolomite unit is 

generally sharp and well defined. A sudden change in 

conditions of sedimenitation must have taken place.; the 

most pronounced changes were the cessation of the 

supply of organic matter and the increase in the supply 

of terrigenous sediment in the form of detrital quartz 

grains. 

Deposition of small amounts of clay alternated with 

the deposition of lime mud, as is indicated by shaly 

partings between the carbonate rocks, especially in the 

lower part of the aphanitic dolomite unit. The lateral 

extent and continuity of the clay layers are unknown 

because the beds are well exposed only in quarries, 

along roadcuts, and in some creek beds, such as Lost 

Tank Canyon. The amount of clay deposited gradually 

decreased, and few or no shaly interbeds occur in the 

upper part of the aphanitic dolomite unit. 

The cessation of the supply of organic material could 

be explained by a breakdown or flooding of one of the 

barriers of the hypothetical embayment and the establishment of open circulation. An alternative and perhaps more plausible explanation is that the sea became 

considerably shallower. Rocks of the aphanitic dolomite unit seem to have formed from an extremely fine 

grained lime mud in very shallow water. Parts of the 

bottom of the depositional basin were occasionally exposed to the air, as is evidenced by the occurrence of 

n1udcracks on some bedding planes of both the dolomite 

beds and the shaly intercalations. Mudcrack patterns 

in dolomites (fig. 15) are somewhat similar to those 

described and illustrated by Ginsburg (1957, p. 94) 

that occur in alternating lime and algal sediment in the 

Florida Keys. The cracks are subaerial in origin, but 

Ginsburg called attention to observations by Straaten 

(1954), who found incomplete mudcracks in sediment 

deposited under a permanent cover of water. The occurrence of crack patterns formed under water on sediment surfaces was most fully discussed by Shrock 

(1948b, p. 197) and by Schafer (1954). The mudcracks in the aphanitic dolomite unit originated subaerially, a fact indicated because they are rather 

common and have a general pattern typical for subaerially formed mudcracks. 

Autobrecciation of slightly indurated lime mud surfaces was common, as is shown by the abundance of 

autoclastic aphanitic rocks; several examples of this 

are discussed on page 35. Very little other evidence 

indicates that the water was agitated, as by current 

action. 

The sediments could have been deposited either close 

to or in the intertidal zone or on a vast mudflat under 

a foot or two of water in a nearly tideless sea where 

small fluctuations of sea level were controlled by changing winds. Deposition on a mudflat is perhaps the 

preferred explana,tion because it accounts for the prevalence of autobrecciation as well as for the scarcity 

of bedding-plane erosion. It would also help to explain 

presence of large detrital quartz grains that could not 

have been transported by the wind except by saltation 

movement. (See discussion on p. 38.) 

The source of the calcium carbonate is difficult to 

determine under conditions of sedimentation heretofore discussed. Apparently little life, except for ostracodes and very few brachiopods, existed on the mudflats. 

The enigmatic calcispheres were most probably planktonic and probably contributed at least part of the 

calcium carbonate. Contributions by algae are easier 

to hypothesize than to prove. Electron micrographs 

of recent aragonitic muds from the Bahamas and a 

Pacific atoll in which the aragonite needles may have 

been precipitated by algae show no resemblance to elec-
ROCKS OF THE MARTIN FORMATION 83 

tron micrographs of aphanitic limestone, but aragonitic 

mud subjected to pressures of a few thousand psi and 

to temperatures of several hundred degrees centigrade 

changes into an aggregate of polyhedral calcite grains 

that is not unlike some aphanitic limestones (Hathaway 

and Robertson, 1960). 

Some of the lime mud apparently changed eodiagenetically into aphanitic limestone, and individual 

beds in some of the measured sections are locally preserved as such (subunit 13 of section 30; subunits 10 and 

22 of section 32; and subunits 9 and 10 of section 34). 

Almost all these rocks contain ostracode fragments, 

calcispheres, or both. 

Most of the lime mud, however, was converted into 

the aphanitic dolomite or slightly calcitic dolomite that 

now forms most of the aphanitic dolomite unit. As 

described on page 41, primary sedimentary structures 

were preserved during dolomitization, but fossil structures were very largely destroyed or obscured. This 

dolomitization process was probably very ~rly diagenetic, or penecontemporaneous. In other words, 

aphanitic dolomite originated directly from dolomitization of the lime mud. This is probably the prevailing 

opinion of contemporary students of sedimentary rocks. 

(See also Cloud and Barnes, 1948, p. 91-92.) Contrasting opinions are discussed on page 41. 

Zen ( 1960) demonstrated that limestone as well as 

dolomite may be in equilibrium in a sedimentary environment but that intermediate types are not. Calcite 

is the equilibrium carbonate under surface conditions. 

Dolomite is relatively more stable at depth, where it 

forms from calcite through reaction with sea water. 

These conclusions agree with the facts of the lithology 

of the aphanitic dolomite unit, where rather pure dolomites exist alongside rather pure limestones, but no 

intermediate types exist. 

Carozzi ( 1960, p. 284) recently suggested that such 

fine-grained dolomites must have been formed by 

volume-for-volume rather than molecule-for-molecule 

replacement of the calcareous sediment by dolomite, as 

is indicated by their general lack of porosity. However, 

if dolomitization occurred before lithification, loss of 

volume would result in compaction. Engelhardt (1960, 

p. 56-58) also pointed out that porosity cannot 

occur under conditions of very e a r 1 y diagenetic 

dolomitization. 

The difference in crystallinity between the aphanitic 

dolomite unit and the finely crystalline fetid dolomite 

unit is difficult to interpret. The original sediments of 

both units must have been similar except for the organic 

constituents in the sediments of the fetid dolomite unit. 

Possibly, dolomitization of these sediments was not 

penecontemporaneous but occurred after lithification 

or during late stages of lithification, perhaps contemporaneously with the eodiagenetic dolomitization of the 

aphanitic dolomite unit. This suggestion finds support 

in the fact that some dolomites are porous, at least in 

the upper part of the fetid dolomite unit. 

Some fine-grained rather than aphanitic rocks also 

occur locally in the aphanitic dolomite unit (pl. 5, fig. 

5). Engelhardt ( 1960, p. 56-58) found it difficult to 

explain the origin of nonporous fine-grained dolomite 

rocks. However, most rocks of this type are possibly 

recrystallized aphanitic dolomites; recrystallization was 

not considered by Engelhardt. A secondary porosity 

may have occurred in such rocks at some later diagenetic 

stage. Dolomite crystals grew freely into the void 

spaces, which were later filled with clear calcite. 

The occurrence of chert in the aphanitic dolomite unit 

poses several problems, some of which have been discussed in the description of that unit (p. 38). Most 

of the chert must be of middle or late diagenetic origin 

because no synsedimentary source of the silica is known. 

After consolidation of the sediment, silica in solution 

must have migrated into the rocks from some outside 

source. Internal origin through solution of detrital 

quartz and replacement of quartz by carbonate in the 

manner suggested by Bourcart and others (1933) and 

by Walker (1957, 1960) may account for only a very 

small part of the chert. The terminal stage in this process is represented by a metasomatic limestone (as discussed by Shvetsov, 1959, p. 738), which originates 

through complete calcitization of a rock such as dolomite 

or sandstone. Shvetzov said that "such rocks are not 

scarce in nature," but he gave no examples. 

As has been described in foregoing sections, peripheral etching of quartz grains and loss or replaceemnt of 

some of the substance of the grains is common, but 

evidence of complete replacement of entire grains has 

not been noted with certainty (Walker, 1960, pl. 1, fig. 

5). "Ghost" clasts in fine-grained dolomites, especially 

in the upper unit, are interpreted as primary aphaniticlimestone clasts rather than replaced quartz grains. 

At least part of the detrital quartz having a grain 

size of about 0.25 1nm or less 'vas blo,-vn onto the mudflats by offshore winds. Larger grains and perhaps 

smaller chert pebbles were rolled along the flats by the 

wind or by wind-generated currents. 

The northeastern shoreline of the sedimentation area 

remained more or less stationary and in the same geo'-

graphic position ~as at the time of deposition of the fetid 

dolomite unit. Sandstone that locally contains fish 

plates was being deposited close to the shore. Exact 

correlation of this sandy facies with the carbonate facies 

is for the most part impossible. 

The present thickness of the aphanitic dolomite unit 

suggests that the uncompacted mud was 200-300 feet 

thick. Most, if not all, of the compaction must have 
84 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

taken place while sedimentation was still in progress; 

sea level at the end of the period of deposition of the 

unit was undoubtedly approximately at the level now 

occupied by the top of the unit. 

UPPER UNIT 

SEDIMENTATIONAL HISTORY 

Although the boundary between the aphanitic dolomite unit and the upper unit is generlally well defined 

in the field, no reliable evidence is available in most 

places to indicatB the nature of the change in sedimentation that must have taken place at this boundary; however, evidence does exist that ~a change from carbonate 

deposition to deposition of ter~igenous siliceous-detrital 

material occurred locally. Wherever the lower part of 

the upper unit is composed of carbonate rock, the rock is 

invariably dolomite; the boundary is drawn generally at the base of the first nonaphanitic commonly 

fine-grained, dolomite. Almost everywhere in the lower 

part of the upper unit, the present features of this type 

of rock are entirely diagenetic in origin, and the primary sedimentary facies of the rock has been destroyed. 

This part of the unit is also almost entirely unfossiliferous; so, neither the rocks nor the fossils indicate 

the nature of the orginal sediment. 

The upper unit laps onto the Precambrian basement 

beyond the area of sedimentation of the two lower units; 

this evidence indicates that sea level must have risen 

relative to the land and that the sea. transgressed across 

the Defiance uplift area in a general northeasterly direction. This assumed rise in sea level brought about a 

slight deepening of the sea in the area southwest of the 

Defiance uplift. This assumption seems to agree well 

with paleontological evidence. Although fossil content varies considerably in a horizontal direction, the 

number and variety of fossils generally in'creases gradually from bottom to top of the unit. The upper part 

of the unit over much of the area of investigation was 

deposited undoubtedly in an open shallow shelf sea in 

an environment that was especially favorable to coral 

and brachiopOd growth. 

At stratigraphic distances of about 50 feet above the 

base of the upper unit, fossiliferous limestones are 

known from some localities such as subunit 18 of section 

6 (Salt River Draw), subunit 13 of section 30 (Diamond 

Point), and subunit 10 of section 32 (East Verde 

River). These rocks are aphanitic limestones that are 

slightly dolomitized in places and contain calcispheres, 

ostracodes, scattered tintinnids ( ? ) , and pteropods. 

Such rock types differ little from the undolomitized 

aphanitic limestones of the underlying dolomite unit. 

A more unusual rock occurs in subunit 18 of section 38 

(Limestone Hills) , which lies at 35 feet rubove the base 

of the upper unit. This rock, too, has a groundmass of 

aphanitic limestone, but it contains abundant remains 

of brachiopods, gastropods, crinoids, and echinoids (pl. 

8, fig. 1). This assemblage indicates a richer benthonic 

life than any observed in rocks of the aphanitic dolomite unit, but it is only a small window into the predolomitization world. 

We can therefore conclude that sedimentation was 

continuous from the aphanitic dolomitic unit into the 

upper unit and that the character of sedimentation 

changed little at this boundary; however, dolomitiza.-

tion of the upper unit was delayed until a later diagenetic stage. Soon after the deposition of the aphanitic 

dolomite unit, however, conditions became favorable for 

a richer and more varied bottom life. 

This change took place gradually, as is shown by the 

appearance, at first sporadic, of corals and stromatoporoids in stratigraphic sections. The earliest appearance 

of these groups, represented by tabulate corals and 

Amphipora, is 50 feet above the base of the upper member in section 13 (southwest branch of Lost Tank Canyon). More commonly, however, first appearances of 

coelenterates are about 100 feet or more above the base 

of the member, as is indicated in table 6. 

TABLE 6.-First appearance of coelenterates above base of upper 

unit of Jerome Member 

Section 

4 

6 

8 

12 

13 

29 

30 

31 

38 

41 

43 

Association 

Amphipora ____________________ - __ ------

Massive stromatoporoids, Amphipora, tabulate corals _______________________ _ 

Massive stromatoporoids, rugose corals ___ _ Amphipora, tabulate corals _______________ _ Amphipora, tabulate corals _______________ _ Tabulate and rugose corals ______________ _ Tabulate corals ________________________ _ 

Massive stromatoporoids, tabulate corals __ _ Massive stromatoporoids, tabulate corals __ _ Tabulate corals ________________________ _ 

Tabulate and rugose corals ______________ _ 

Feet above 

base of 

upper member 

60 

95 

140 

135 

50 

90 

120 

138 

88 

180 

171 

Thus, the environmental conditions only gradually 

improved sufficiently to allow corals and stromatoporoids to migrate into the area.. Among the first arrivals 

were A1npkipora and Thamvnopora, which formed 

"meadows" of the type described on page 58. These 

fossils are most common in the middle part of the upper 

unit. Such biocoenoses must have required reasonably 

clear water, at least for long periods at a time, and by 

this time the sea floor was presumably well below the 

zone of turbulence caused by ordinary waves. 

Continuing improvement of environmental conditions 

for benthonic life is indicated by the rich thanatocoenoses of stromatoporoids, corals, and brachiopods; improvement is further suggested in the upper third of the 

I 

unit by coquinas of brachiopods which have been transported only short distances. Evidence from most of 
ROCKS OF THE MARTIN FORMATION 85 

the area suggests that sedimentation in this uppermost 

part of the upper unit oecurred quietly on a deepening 

shelf. The sea transgressed over low-lying areas of the 

Defiance uplift, approximately as far as the present city 

of Holbrook, and Pine Island and Christopher Island 

were only then cut off from the mainland. 

During much of the sedimentation of the upper unit 

the Defiance uplift reduced in size, must have been an 

area of slightly undulating topography that was a 

source, though not a significant one, of terrigenous sediment. A source somewhere in the southeast, outside the 

study area, was more important, as is indicated by the increase in amounts of sandstone, siltstone, and shale in 

that direction. (See the discussion on p. 96-97.) Attention is again called to the faunal change from mixed 

stromatoporoid-coral-brachiopod assemblages to predominantly pure brachiopod assemblages in the same 

direction. 

Glimpses of the original nature of the carbonate sediment from which the rocks of the upper member were 

formed may be obtained from the limestone beds that 

are intercalated with the predominating dolomites in 

many sections. These limestones are typically aphanitic to very fine grained and contain rich microassemblages of calcispheres, "U mbella," ostracodes, pteropods, 

and much unidentifiable "hash." The predominant 

carbonate sediment of the upper unit must ha,ve been a 

fine mud that gradually became richer in organic remains and had a tendency to form stromatoporoid-coral 

biostromes. The biostromes are rarely dolomitized and are preserved as massive limestone. 

The lime muds were first compacted into aphanitic or 

very fine grained limestones, some of which are preserved in many places throughout many of the stratigraphic sections. Most of the limestones of the upper 

unit, however, have been dolomitized. The manner in 

which the rocks of the upper unit have been dolomitized 

poses many puzzling questions that are still unanswered. 

DOLOMITIZATION 

In contrast to the underlying aphanitic dolomite unit 

in which dolomitization produced rocks of generally 

very uniform lithology, the rocks of the upper unit have 

been affected by dolomitization in many different ways, 

producing a great variety of rook types. Dolomitic 

rocks in the upper unit range from aphanitic to 

medium grained saccharoidal. Most of the rocks are 

dolomites or slightly calcitic dolomites. In many sections undolomitized limestones are intercalated in predominantly dolomite sequences. One major area of 

undolomitized or little dolomitized limestone is situated 

in the upper Salt River Draw area east of Canyon 

Creek near Chediski; however, this area was not studied 

in detail. 

Intermediate rock types such as highly dolomitic 

limestones and highly calcitic dolomites exist but are 

uncommon. Typically, dolomitization of rocks of the 

upper unit proceeded by the formation of dolomite 

nuclei, which grew into euhe,dral rhombohedra. In 

some limestones the rhombohedra are small and 

scattered, and a gradation exists from this type of rock 

to high-grade dolomite rocks that consist typically of 

aggregates of idiomorphic and hypidiomorphic dolomite rhombohedra. In intermediate rock types varying amounts of dolomite rhombohedra are present, and 

enough of the original limestone is left unaltered to 

allow reconstruction of the primary sedimentational 

environment. 

In rocks in which this kind of dolomitization occurs, 

dolomite is an authigenic mineral that differs from 

most other authigenic substances except silica in that 

it tended to replace the entire parent rock. Fossils and 

other primary sedimentary structures were generally 

entirely obliterated during this process; the final 

product of the process was an entirely crystalline dolomite in which residual calcite may be found composing 

a thin lining of the dolomite rhombohedra (pl. 8, 

fig. 2). 

The formation of authigenic dolomite was probably 

not an early diagenetic process but took place in the 

solid limestone during 1niddle or late diagenesis. This 

conclusion follows from the manner in which dolomite 

crystals grew across microfossils and small-scale sedimentary structures. The cryptocrystalline texture of 

the limestone and microscopic shell structures were 

completely replaced by the crystalline dolomite, and not 

even "ghost" structural features remain. 

The proportion of dolomite rock to total carbonate 

rock generally decreases somewhat from the bottom to 

the top of the upper unit (pls. 22 and 23); more limestone beds are present in the upper part of the unit. 

In the Jerome area, however, the entire upper unit 

consists of dolomite rock. 

The presence of some aphanitic dolomite beds in the 

upper part of the upper unit is difficult to explain. If 

such rocks are interpreted as penecontemporaneous 

dolomites, in analogy to the dolomites of the aphanitic 

dolomite unit, it must be explained why conditions for 

penecontemporaneous dolomitization existed only 

locally, temporarily, and at intervals during the time 

of deposition of the upper member. Such an explanation cannot yet be offered. 

SILICA 

In the upper unit of the Jerome Member, silica in the 

form of chert is less common than in the aphanitic dolomite unit. No special study of the occurrence and distribution of chert in the upper unit was made. 
86 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

The occurrence of authigenic quartz, mostly as 

doubly terminated small crystals, is mentioned on 

page 45. One noteworthy occurrence of the quartz 

is in a limestone bed in section 34 (Tonto Natural 

Bridge), 199 feet above the base of the Jerome Member 

(pl. 7, fig. 2). The limestone is aphanitic and contains 

some brachiopod shells and calcispheres. The quartz 

occurs in well-formed doubly terminated crystals which 

are as large as half a millimeter in length. The crystals 

contain many minute inclusions of a highly birefringent 

material, apparently calcite. In addition to the quartz 

crystals, well-formed dolomite rhombohedra are 

scattered throughout the rock. 

The presence of finely dispersed calcite in the quartz 

crystals sho,vs that the crystals were formed as metasomatic replacements of the limestone rather than as 

secondary overgrowth on quartz grains of detrital 

origin. The secondary-overgrowth mode of formation 

was first described by Irving and Van Rise (1884). 

Cayeux (1916, p. 196-197) recognized that authigenic 

quartz can be formed in sediments in both wavs. 

Authigenic quart.z crystals are fairly co~mon in 

limestone. More recently they were described by 

Topkaya (1950), Black (1949), and Fiichtbauer 

(1950). Some references to earlier observations are 

given by Boswell (1933). However, published information does not always clearly indicate whether the 

"authigenic" quartz was built around detrital grains or 

if it was newly formed. Fiichtbauer (1950, p. 245) 

described doubly terminated quartz crystals from fossiliferous Triassic limestone near Gottingen, West Germany. He also specifically mentioned calcite inclusions 

in the crystals. 

Topkaya (1950, p. 94), who studied authigenic quartz 

from several carbonate rocks in the Swiss Alps, concluded that the quartz formed in the solid rock at temperatures of less than 100°C after lithification of the 

sediment and that the silica was derived from material 

within the rock. In the Jerome Member, particularly 

in the stratigraphic section at Tonto Natural Bridge, 

abundant detrital quartz occurs from which the material for the formation of authigenic quartz could have 

been derived. (Evidence for the corrosion of detrital 

quartz in a carbonate medium is discussed on 

page 83.) Whereas this source is hardly sufficient to 

explain major chert accumulations (Walker, 1960), 

more than enough silica should have been available 

from it to account for the relatively small amounts of 

authigenic quartz and for the silicific.ation of fossils. 

Silicified fossils are common, especially throughout 

the upper part of the upper unit; locally entire limestone beds are replaced metasomatically by silica, and 

fossil structures are preserved. Silicification of brachiopod shells in many places is incomplete, and only a 

thin film on the inner and outer surfaces of the shells 

is affected; a space between these films consists of crystalline calcite (pl. 14, fig. 2). This type of preservation 

is particula.rly common in dolomitic limestone and calcitic dolomite. Apparently, the original shell material 

of the fossils was recrystallized into coarser calcite and 

escaped dolomitization. Replacement of part of this 

calcite by silica was a later diagenetic process. 

Corals also are commonly silicified. In one specimen 

(pl. 15, figs. 2 and 4) the entire skeleton as well as the 

secondary calcite filling inside the skeleton were replaced by fine-grained quartz. Careful comparison of 

the photomicrograph taken in ordinary light and one 

taken between crossed nicols shows that some septa and 

dissepiments were changed to very finely crystalline 

quartz, whereas others now form part of larger quartz 

crystals 'vhose boundaries cut across fossil structures 

and the intervening spaces alike. The entire fossil is 

more coarsely crystalline than the silicified rock in 

which it is embedded. 

Turner (1899, pl. 5) illustrated a similar silicified 

rock containing a foraminifer that was also clearly 

recognizable when the slide was viewed between crossed 

nicols; the matrix inside the shell was replaced by an 

aggregate of quartz crystals that were finer than the 

replacing crystals outside the shell. Irving (1911, p. 

641) suggested that such textural details were retained 

during replacement because they represented irreplaceable impurities. He did not discuss the nature of these 

impurities. 

The skeletal elements (septa, dissepiments) of rugose 

corals such as the one described in the foregoing paragraph were originally calcite that had been deposited 

in either spherulitic or lamellar form (Hill, 1956, p. 

F235). The free space inside the corallum must have 

been filled with secondary clear crystalline calcite. The 

skeletal structure of the fossil was thus retained owing 

to differences in the crystalline form of the replaced 

calcite rather than to the presence of nonreplaceable 

impurities. 

A very different type of silicification of a coral was 

recently described by Lund (1960) in a specimen from 

Mioeene roeks in Florida. Here the entire coral substance \vas first removed by solution, and the remaining 

cavity was filled with an outer layer of quartz and an 

inner filling of chaleedony. 

Some findings of Storz (1931) may help to explain 

selective silicification of fossils in earbonate rocks, although Storz himself did not deal with this subjeet. 

He demonstrated ( 1931, p. 305) that seleetive silicifieation in carbonate rocks occurs preferably when the 

roek is a mixture of coarse-grained and fine-grained 

aggregates. The greater the dift'erenee in size grades, 

the more pronounced is the silification. Silica-bearing 
ROCKS OF THE MARTIN FORMATION 87 

solutions migrate through the rock until they are under 

conditions favorable for precipitation. Such conditions, according to Storz (1931, p. 238), may be present 

·where differences in texture or in shape or composition 

of mineral aggregates occur. Another important consideration is that in some places the most easily dissolved carbonate is attacked and replaced first (Storz, 

1931, p. 362). 

The foregoing observations may explain selective 

silicification of fossils, especially in fine-grained rocks, 

beeause a fossil constitutes a coarser aggregate of carbonate minerals than does the matrix; the aragonite or 

calcite prisms composing the fossil are probably more 

easily dissolved than those of the rock itself. This 

suggestion, however, needs verification by laboratory 

experiments. 

DISCUSSION OF ISOPACH MAPS AND NOTES ON WEU.S 

Field data on the distribution and thickness of the 

Beckers Butte Member are insufficient and too widely 

spaced to '"arrant construction of an isopach mapo 

However, the available information has been compiled 

in plate 27 A to show the great variation in thickness 

of this member and its disappearance toward the 

northeast. 

To show features of the Jerome Member in desirable 

detail, three isopach maps were constructed: (1) for 

the entire Jerome Member (pl. 27 B) , ( 2) for the combined fetid and aphanitic dolomite units of the Jerome 

Member (pl. 270), and (3) for the upper unit (pl. 

27 D). ,;v ell data were utilized in the construction of 

the map of the upper unit in the northeastern part, 

where the Devonian lies deeply buried under younger 

Paleozoic and Mesozoic rocks. For convenient reference, the wells have been given letter designations and 

are referred to as "A" well, "B" well, and so on. 

Follo,ving are the names of the well used, source of 

infonnation, and the thickness of the Jerome Member, 

in feet, in the wells : 

Well name (source of information) Thickness 

"A" well. Great Basin Oil Co., Taylor-Fuller No. 1 

(Huddle and Dobrovolny, 1945, section 21) _ 0 

"B'' well. Northern Aztec Land and Cattle Co. "A" (well 

log obtained from American Stratigraphic 

Co.)_____________________________________ 250 

"C" well. Union Oil Co. of California and Continental 

Oil Co. of New Mexico-Arizona, Land Co. 

No. 1 ·wen (Huddle and Dobrovolny, 1945, 

section 20)------------------------------ 0 

"D" well. Union Oil Co. of California and Continental 

Oil Co. Aztec Land and Cattle Co., No. 1 

w·en (Huddle and Dobrovolny, 1945, section 19)--------------------------------- 20 

''E'' well. Lion Oil (Monsanto) No.1 Cabin Wash (well 

log obtained from American Stratigraphic 

Co.) ----------------------------------- 36 

"F" well. A. M. Lockhart, Aztec Land and Cattle No. 1 

(cuttings examined in Museum of Northern 

Arizona, Flagstaff)---------------------- 1 80 

"G" well. Pan-American Petroleum Corp., New MexicoArizona Land Co., B-1 (well log obtained 

from American Stratigraphic Co.)-------- 93 

1 Thickness possibly 89ft. 

The isopach map for all the Jerome Member shows 

the thin margins of the Devonian rocks toward the 

northeast, in the general area south of Holbrook. The 

trend of the edge is somewhat more complicated than 

previously realized. Log data for "A" well and "C" 

well (the equivalent of sections 21 and 20 of Huddle 

and Dobrovolny, 1945) have been known for many 

years. In both these 'veils, Redwall Limestone rests on 

Precambrian, and no Devonian rocks are present. Recently 250 feet of Devonian rocks was unexpectedly 

penetrated in "B" well, situated between "A" and "C" 

wells, only a little more than 3 miles southwest of the 

"A" well. The Devonian rocks penetrated in "B" well 

are mostly dolomite and shale. They were deposited 

either in a local depression of the Precambrian surface 

or in an embayment extending eastward from an open 

shelf sea to the west. The embayment interpretation is 

shown on the map. 

The absence of Devonian rocks in "C" well may indicate ( 1) a sma1l island, if Devonian rocks should 

prove to be continuous from "B" well to "F" well, or 

(2) a spur (on the end of which "C" well is located) 

extending westward from the main area of the Defiance 

uplift. 

Toward the southwest, a broad belt of rocks having 

thicknesses less than 100 feet apparently occurs, although control points used to determine its presence are 

few. '¥here the Jerome Member crops out at the foot 

of the Mogollon escarpment in Gila County, the thicknesses a.re somewhat more than 100 feet. In southwestern Navajo County, thicknesses are less than 100 

feet, and the 100-foot contour is shown projecting far 

into the southwest corner of the county on the map. 

The overall isopach picture shows a gradual southwestward increase in thickness of the Jerome Member. 

In sections 16, 17, and 18, thicknesses are about 200 feet. 

In sections 8 and 12 thicknesses are 300 feet or more, and 

more than 400 feet of strata are recorded from Huddle 

and Dobrovolny's section 8 (Cliff House Canyon; see 

Huddle and Dobrovolny, 1952, p. 100-101) and from 

the lower Salt River Draw (section 6). The pattern 

of thickness of the stratigraphic sections measured in 

the belt from the upper Christopher Creek area southeastward to the junction of White River and Black 

River indicates an approximate northwesterly trend 
88 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

of the isopachs; thickness increases toward the southwest. 

Along the lower course of Christopher Creek and 

around its junetion with Tonto Creek, the isopach pattern is complicated by the presence of Christopher 

Island, where Devonian rocks are either absent or, at 

most, are represented by a few feet of conglomerate and 

sandstone. Isopach lines on the map are closely 

crowded around this area; thicknesses increase abruptly 

west of the area. 

About 25 miles west of Christopher Island is a probably larger island-here called Pine Island. The margin of the Jerome Member on the east side of this area 

is described in more detail on page 45. The island 

was called Pine Ridge by Huddle and Dobrovolny, who 

interpreted it to be a northern promontory of a southern 

landmass. However, the thickness of the Jerome Member inereases toward the south and southeast of the Pine 

area : it is 402 feet in lT pper Sycamore Canyon (section 33), 389 feet at Tonto Natural Bridge (section 34), 

and 394 feet near the junction of East Verde and Verde 

Rivers (Limestone Hills, section 38). These findings 

are in harmony with observations made in the eastern 

part of the area discussed above and indicate that the 

original deposits had a thickness of about 400 feet in 

the triangle between the Verde and Salt Rivers; the 

area is now occupied by the Mazatzal Mountains and 

the Sierra Ancha. Further reasons for this interpretation are indicated by the pattern of distribution of 

thickness and facies, especially of the fetid dolomite and 

apHanitic dolomite units of the Jerome Member, which 

are discussed in the following paragraphs. 

About halfway between the middle course of the Salt 

River and the San Carlos River, the Devonian section 

thins, and at Seven Mile Creek, about 15 miles northeast 

of Globe, the entire Devonian sequence is only 258 feet 

thick. The Beckers Butte Member and all units of the 

Jerome Member are present at this locality. 

In the northwestern part of the area., along the upper 

Verde River and on Mingus Mountain, the thickness 

of the Jerome Member is more than 400 feet at Jerome 

(section 41) and probably more than 500 feet in Upper 

Hull Canyon (section 42). 

Only the upper part of the Jerome Member is known 

at Elden Mountains, in the northern part of the area 

(section 44), and because this section consists of rocks 

having a decidedly offshore faeies, the total thickness 

of the member here is probably comparable to the 450 

feet at Jerome. 

A more detailed picture of the pattern of distribution 

and thickness can be obtained by plotting separate isopach maps for the lo,ver and upper parts of the 

Jerome Me1nber. Since the fetid dolomite and aphanitic dolomite units are closely related stratigraphically~ 

their thicknesses have been combined into one isopach 

map (pl. 27 0). As the map shows, the two units wedge 

out along a line that extends in a winding course from 

the southwest eorner of Navajo County northwestward 

to the headwaters of Tonto Creek. From the creek the 

boundary follows probably more or less the foot of the 

Mogollon escarpment in the direction of Pine Island. 

This boundary marks the edge of the Defiance uplift 

that existed during the deposition of the lower part of 

the ,Jerome Member. Thus, at that time the Defiance 

uplift extended 40-50 miles farther southwest than at 

the end of Jerome time, and Pine Island formed a mere 

promontory of this uplift. 

The isopach pattern on the map is consistent with 

the postulate of an earlier more extended Defiance positive area, because at all available control points the 

thickness of the combined fetid and aphanitic dolomite 

units increases consistently from the margin in a general 

southwesterly direction. The units have a combined 

thickness of 50 feet 0.5-5 miles from this margin, 100 

feet 1-7 miles away, and 150 feet about 4-8 miles away. 

Across the greater part of the triangular area between 

the Verde and Salt Rivers and as far south as Superior, 

thieknesses are uniformly a little more than 150 feet. 

In some sections measured close to the edge of the two 

units, numerous intercalations of sandstone occur in 

the aphanitic dolomite unit (for example, sections 17 

and 18) ; .elsewhere both units are composed entirely 

or almost entirely of siliceous-clastic rocks (for 

example, sections 28 and 29). 

The thiekness of the two units increases insignificantly northwestward from about 175 to slightly more 

than 200 feet. The area in which the beds are 150 feet 

thick approximately follows the Verde River; the 

courses of the areas in which the units are of another 

given thickness cannot be known with any degree of 

certainty. 

A third isopaeh map (pl. 27 D) shows the distribution 

of the upper unit of the Jerome Member. The northeastern edge of the lower two units is also shown in 

this map because it indicates the southwestern edge of 

the area in which the upper unit rests directly on Precambrian rocks. The unit here is generally less than 

100 feet thick, except perhaps in depressions such as 

the one in which "B" well is located; it consists of 

dolomite and some siliceous-clastic rocks. The edge of 

the fetid and aphanitic dolomite units follows very 

roughly the area in which the upper unit is 100 feet 

thick. 

From the edge of the dolomite units toward the 

southwest, the upper unit generally increases in thickness. The few available data suggest that a former 

area of 1naximum thickness existed in the region between Tonto Creek and Salt River, which is now largely 
ROCKS OF THE MARTIN FORMATION 89 

occupied by the Sierra Ancha. The thickness of the 

unit in this area \vas probably slightly in excess of 300 

feet. 

Toward the southeast across the Salt River, the upper 

unit thins somewhat. The 200-foot isopach can be reconstructed with some confidence and is drawn as extending from the upper Salt River, approximately at 

Flying V Canyon (section 3), southwestward to Globe. 

Beyond Globe thicknesses at the few control points 

are consistently less than 200 feet. 

Pine Island and Christopher Island formed during 

the time of deposition of the upper unit. During deposition of the fetid and aphanitic dolomite units, these 

areas were still part of the mainland of the Defiance 

uplift. Their existence is responsible for the somewhat 

irregular pattern of thickness of the upper unit in the 

upper Tonto Creek and East Verde River area. 

Northwest of Pine Island, upstream along the Verde 

River, and in the Jerome area, the unit increases slightly 

to somewhat more than 300 feet, and a similar thickness is estimated for this unit at the incompletely exposed section in the Elden Mountains. 

AGE AND CORRELATION OF THE MARTIN FORMATION 

BECKERS BUTTE MEMBER 

The oldest fossils in the Martin Formation occur at 

the top of the Beckers Butte Member and constitute an 

assemblage of psilophyte plants briefly described and 

evaluated by Teichert and Schopf ( 1958). The assemblage contains abundant remains of naked branching axes of types eommonly assigned to H osthnella sp. 

and to Aphy1lopte,ris sp. Spineless psilophytes are 

characteristic of both Lower and Middle Devonian 

rocks. Associated with these plants are fertile 

structures that resemble Oooksonia, Hicklingia, and 

Rhynt'a. Although these sporangia are generally 

smaller, many of them occur in pairs attached to a 

short dichotomized stalk, and one specimen has five 

successive diehotomies within a distance of 6 mm. Some 

of the specimens resemble H edeia and may be congenerie 

with it. Other, curved or somewhat falcate, sporangia 

rese.mble Da1osonites. 

Most of the spores in this fossil horizon are not well 

preserved. Some resemble spore types deseribed by 

Lang (1926) from the Old Red Sandstone of Scotland. 

Some sporelike spheroidal bodies having attaehed filaments may be related to the genus Leiosphaera Eisenack, 

whieh was first described frmn Silurian rocks of the 

Baltic region. 

The only other psilophyte flora from western North 

America is the one described by Dorf (1933, 1934a, 

1934b) from the Beartooth Butte Formation of Wyoming, but the only elmnents it has in common with the 

flora of the Beckers Butte Member are smooth 

H ostimella-type branches. The microfossils of the 

Beartooth Butte have apparently not yet been studied. 

On the basis of its associated fish fauna, the age of the 

Beartooth Butte has been determined to be Early 

Devonian (Bryant, 1932 and later papers). 

The exact time relationships between the Beckers 

Butte Member and the Beartooth Butte Formation are 

thus in doubt, although both are older than Late Devonian. More reeently, Sandberg (1961) showed that the 

Beartooth Butte is widely distributed in western Wyoming and Montana. Like the Beckers Butte it consists 

mainly of channel deposits connected by thin layers of 

sediments deposited outside the channels; it is overlain 

by rocks of Late Devonian age. 

No fish remains have been found in the Beckers Butte 

Member; the member is probably entirely fluvial except 

for local shale and dolomite beds at the top, which were 

deposited probably in shallow clay pans. Because it is 

uncertain whether psilophyte flora of the Beckers Butte 

Member is Early or Middle Devonian in age, the correlation of this member with the Beartooth Butte must 

remain in doubt. 

As Teichert and Schopf (1958) indicated and the 

present report more amply documents, no evidence of 

an unconformity between the Beckers Butte Member 

and the Jerome Member is known. Indeed, a somewhat 

gradational contact is indicated locally by the presence 

of intercalated thin dolomite beds at the top of the 

Beekers Butte, although the contact between it and the 

lowest unit of the Jerome Member is generally sharp 

and well defined. Beeause of the conformity between 

the Beekers Butte Member and the Jerome Member, 

Teichert and Schopf ( 1958) considered the Beckers 

Butte more likely to be Middle Devonian than Early 

Devonian in age; this consideration is strengthened by 

detailed studies of the regional distribution and lithofacies of the two members presented in the present 

report. 

If the foregoing arguments are valid, the Beckers 

Butte Member and the Beartooth Butte Formation are 

somewhat different in age. Sandberg (1961) suggested 

that the Beartooth Butte Formation has a general correlation and environmental continuity southwestward 

with the Water Canyon Formation of central Utah 

(Williams, 1948, p. 1138), which is also of Early Devonian age. Additional study of the area between central 

lTtah and central Arizona is required to determine the 

physieal relationships of these formations with the 

Beckers Butte Member of the Martin Formation. 

JEROME MEMBER 

Fortunately, all fossil assemblages having a precisely 

datable age are concentrated in the upper part of the 
90 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

upper unit of the Jerome Member, making it possible 

to put a rather accurate upper time limit to its stratigraphic correlation. Because no precisely datable fossils occur in the lower part of the upper unit or in the 

aphanitic dolomite and fetid dolomite units of the member, evidence for the age of the upper part of the upper 

m1it is discussed first. 

The regional stratigraphic study of the upper unit 

has shown that over most of the area of its distribution, 

the upper unit contains many abundantly fossiliferous 

beds, especially in its upper half, and generally the 

uppermost 150 feet. The 1nost richly represented 

groups in these fossil horizons a,re stromatoporoids, 

corals (both rugose and tabulate), and brachiopods. 

Future studies may be expected to show that conodonts 

constitute another important group; so far they ha,ve 

only been studied in one locality. Both corals and 

brachiopods, as well as the single conodont assemblage, 

furnish accurate and mutually corroborative evidence 

of the late Frasnian age of the uppermost 100-150 feet 

of the Jerome Member. 

W. A. Oliver, Jr., (written commun., 1959 and 1960) 

examined collections from 42 beds, and his identifications are inserted in the appropriate places in the section descriptions. The most important assemblages for 

correlation are the following: 

Section 1 (Sawmill), subunit 4: 

Pachyphyllum sp. 

Section 7 (upper Salt River Draw) , subunit 5 : 

Tabellaeplwllum peculim·is Stumm 

Section 8 (east side of Oanyon Oreek), subunit 22: 

H exagonaria accidens Stumm 

H exagonaria sp. 

Pachyphyllum cf. P. woodmani (White) 

Alveolites sp. 

Thamnopora sp. 

Section 10 (Spring Canyon), subunit 2 : 

Disphyllum? n. sp. 

Tabulophyllum n. sp. 

Alveolites sp. 

Thamnopora sp. 

Section 32 (East Verde River), subunit 34: 

Pachyphyllum sp. 

Tharnnopora sp. 

Section 32 (East Verde River), subunit 30: 

Pachyphyllurn sp. 

Oliver assigned a Frasnian (early Late Devonian) 

age to these six assmnblages, all of which are from the 

uppe'r part of the upper unit of the Jerome Member. 

The genera Tabulophyllum, Pachyphylhtm, and Tabellaephyllun1 are of special importance for dating. 

With the exception of Tabellaephyll~tm peculiaris, 

H exagonaria accidens Stumm, and Pachyphyllum sp. 

cf. P. woodmanl (White), described by Stumn1 (1948, 

p. 41) frmn the 1fartin Limestone of the western part 

of the Bisbee quadrangle, no coral species from the 

Martin Limestone of southeastern Arizona have as yet 

been identified conclusively from the Jerome Member 

of the Martin Formation in central Arizona. Additional collecting and further systematic work is needed 

to determine the degree of relation between the two 

coral faunas. 

Most stromatoporoids and tabulate corals belong to 

genera whose range is at least Middle to Late Devonian 

or longer, and because most species have not been 

identified, they cannot be used for precise correlation. 

A selection of representative brachiopods from the 

upper part of the upper unit of the Jerome Member 

was studied by P. E. Cloud, Jr., (written commun., 

1960) and, with the help of his identifications, I identified other collections. A list of brachiopod species that 

have so far been identified from the upper unit of the 

Jerome is given on page 58. Among those of partieular importance for age determination and correlation are Schizophoria iowensis (Hall), Atrypa 

dm-'oniana va,r. bentonensis Stainbrook, "A." owenensis 

W~bster, Spinatrypa cf. S. rotumda Stainbrook, Platyrachella cf. P. mcbridei (Calvin), Oyrtmspir£fer whltneyi (Hall), and Theodos8ia ef. T. hnngerfordi (Hall). 

According to Cloud (written commun., 1960), the 

fauna has affinity with that of the Hackberry Shale of 

Webster ( 1889) and Independence Shale in Iowa, the 

High Point Sandstone of Clarke (1885) of Late Devonian age in New York, and the Sly Gap Formation of 

Stevenson (1941) of New Mexico; the age therefore, is 

about middle Late Devonian (late Frasnian). This 

age, of course, is exactly where Cooper (1942) put the 

Martin and Jerome on the Devonian correlation chart. 

Evidence supplied by the conodonts furnishes additional support for this correlation. The only assemblage so far identified-from section 43 (upper Verde 

River), subunit 26-is listed on page 44. Two of the 

species allow designation of a restricted age (B. F. 

Glenister, written commun., 1960) : Polygnathus 

nornwli.s Miller and Youngquist is late Frasnian in age, 

and Pabnatolepi8 triang1.1Jaris Sannemann is restricted 

to middle and late Frasnian (Io/y and IS). P. triangular,is, according to Glenister, has a worldwide distribution and is a reliable zone marker. This conodont 

assemblage was obtained in section 43 from the highest 

observed fossiliferous bed, 93 feet below the top of the 

Jerome Member. 

Umbella Maslov is useful for correlation of the 

upper unit of the Jerome Member and occurs at many 

localities, especially in section 31 (Webber Creek), subunit 31, about 115 feet below the top of the Jerome 

Member. This somewhat enigmatic fossil (see pl. 21 

fig. 1) is described on page 103. The same fossils, 

described by Lombard and Monteyne (1952) as "calci-
ROCKS OF THE MARTIN FORMATION 91 

sphire de forme A," are known from rocks of Frasnian 

age in Belgium. More recently, Bykova and Polenova 

(1955) described several species of the genus from 

southeastern European Russia, where they occur in 

strata ranging from late Givetian to early Famennian 

in age, but the principal distribution of the genus, 

including that of the type species Umbella bella Maslov, 

seems to be in the Frasnian. 

Paleontological evidence thus indicates a late Frasnian age for the upper part of the upper unit of the 

Jerome Member. Since the entire upper unit represents one unified stratigraphic and sedimental complex 

despite its facies differentiation, all its rocks are probably at least Frasnian and possibly late Frasnian in age. 

No stratigraphically important difference seems to exist 

between the rich faunas in the upper part of the unit 

and the poorer faunas in the lower part, except that 

the poorer faunas comprise fewer species and are 

generally much less well preserved. . 

No paleontologic criteria exist for the correlation of 

the fetid and aphanitic dolomite units of the Jerome 

Member. The fetid dolomite unit is unfossiliferous 

except for a few small spherical bodies of doubtful, 

possibly algal, affinities. 

The aphanitic dolomite unit, although patchily fossiliferous, especially where incompletely dolomitized, 

contains no diagnostic fossils that can be used for exact 

stratigraphic correlation. Except for calcispheres it 

has no specific forms in common with the upper unit. 

However, the occurrence of Hypotetragona sp. near 

the top of the aphanitic dolomite unit in section 32 

(East Verde River) may be significant. The genus 

has been found by C. A. Sandberg (oral commun., 1960) 

in the middle part of the lower member of the tT efferson 

Formation near Livingston, Mont. (Fossil identification was by Jean Berdan in written communication to 

Sandberg, 1960). According to Sandberg, Hypotetragona sp. occurs about 175 feet above the base of the 

Jefferson Formation, which is early frasnian in age. 

Definite identification of the species from these two 

localities would strongly support the suggestion of a 

Frasnian age of the aphanitic dolomite unit, but this 

awaits more detailed paleontological work. 

The exact position of the base of the Frasnian in the 

Jerome Member, therefore, can not be determined. It 

may be at the base of the aphanitic dolomite unit, or it 

may possibly be as low as the base of the fetid dolomite 

unit. 

Thus, a determination of whether the entire Jerome 

Member or only part of it is of Late Devonian age. 

requires additional investigations. 

745-100 Q.----.64-5 

COMPARISON WITH OTHER DEVONIAN STRATA IN 

THE ROCKY MOUNTAIN PROVINCE 

Broadly speaking, the Martin Formation corresponds 

to the Sly Gap Fornnation of Stevenson (1941) of New 

Mexico, to parts of the Devils Gate Limestone of N evada, and to the Jefferson and Darby Formations of 

Wyoming and Montana. A detailed correlation, however, is not simply made, and significant differencesin 

the paleontologic features of the formations are apparent. Recent conodont studies by Clark and Becker 

(1960) have shown that the age of the lowermost part 

of the Devils Gate Limestone is late Frasnian. . This 

part of the formation is probably that which Merriam 

(1940, p. 9) named the Sp-irijer argentarius zone and 

which he then regarded as late Middle Devonian in age. 

Nolan and others (1956, p. 51) concluded that the 

boundary of the Middle and -Late Devonian is at the 

base of the Spirifer argentarius zone, .and this conclusion has been further corroborated by the paleontological studies of Clark and Becker. 

Therefore, the upper uni_t of the Jerome Member of 

the Martin Formation can probably be 'correlated with 

the lower part of the Devils Gate Limestone, but many 

details remain to be worked out. No species ha.ve as yet 

been discovered that are common to both the Devils Gate 

Limestone and the Jerome Member. 

Little recent detailed info.rmation is available on the 

paleontology of the Devonian rocks of Utah, Colorado, 

Idaho, Wyoming, and Montana. 

Fossils from the Jefferson Formation of Wyoming 

were first described by Kind.le (1908), and since that 

time few additions to knowledge of the formation have 

been made (Laird, 1947; Kottlowski, 1950). The fauna 

listed by Laird (1947, p. 453) from unit Db of the Jefferson. of northwestern Montana resembles the fauna 

from the Martin Formation in _general aspect. It is a 

mixed brachiopod-cor:al assemblage composed of species 

of. D·isphyllum, Tabulophyllum, Atrypa, Sp-inatrypa, 

Schizophoria, and Oyrtospirifer, among others; all 

these genera are common in the Martin Formation 

although specific resemblances seem to be few. A small 

conodont fauna described by C. L. Cooper (1.945) from 

the basal part of the J effe~son Formation, Flath,ead 

Range, Mont., is middle Frasnian in age. In general, 

then, the Jerome Member of the Martin apparently correlates at least with the lower part of the Jefferson Formation of Montana. 

The Devonian faunas of Alberta have become better 

known recently and many biostratigraphic zones ha;ve 

been distinguished (Warren, 1949; Warren and Stelck, 

1950, 1956), but correlation of individual zones with 

fossiliferous beds in the Rocky Mountains of the United 
92 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

States is difficult. Langenheim ( 1957) described a Late 

Devonian fauna from the Swisshelm Mountains of Cochise County, Ariz., that occurred below beds containing corals and brachiopods typical of the Martin Limestone. He correlated this faunal zone with the Nudirostra athabMcensis zone of McLaren ( 1954) in Alberta. 

The upper half of the N. athabasoensis zone contains 

Tilmanites, a goniatite characteristic of the earliest 

Frasnian; if Langenheim's observations are correct, the 

Martin fauna of Cochise County should be younger than 

earliest Frasnian. This, of course, agrees with the conclusion presented on page 91 that the upper fauna of 

the Jerome is later Frasnian in age. 

The Martin fauna. has fossils in common with three 

fossil zones defined by Warren and Stelck (1956, p. 6). 

These zones are, from bottom to top, ( 1) the zone of 

M acgeea proteus, (2) the zone of Tenticosp·irifer cyrtinaformis, and (3) the zone of Spirifer strigosus. These 

three zones combined correspond to the N udirostra 

albertensis zone of McLaren ( 1954). Genera common 

to both the Alberta and the Arizona faunas are Tabulophyllu.rn, Pachyphyllum, Hewagonaria, Aulopora, 

Alveolites, Thamnopora, Nervostrophia, Schizophoria, 

Atrypa, Spinatrypa, Cyrtospirifer, and Tent~~cospirifer. 

Closely related or identicai species found in the two 

provinces are Atrypa de·voniana var. bentonensis Stainbrook, Tenticospiri fer cyrtinaformis ( IIall and Whitfield), "Spirifer" strigosus Meek, and Schizophoria 

iowensis Hall. 

Faunistic relationships exist also between the Martin 

fauna and the next younger zone of Manticoceras sinuosum in Alberta (Warren and Stelck, 1956, pis. 23-24), 

as is indicated by common occurrence of Cyrtospirifer 

whitneyi and of Theodossia sp. 

Warren and Stelck's succeeding zone is the zone of 

Nudirostra walcotti, which includes the Nudirostra gibbosa walcotU-according to McLaren, corresponding to 

the Cyrtospirifer zone of Merria.m ( 1940) in Nevadaand N udirostra gibbosa seversoni zones of McLaren 

(1954, p.173). 

Thus, the "1\-fartin fauna" as presently though incompletely known from the upper parts of the Martin Limestone and the Jerome Member of the Martin Formation 

in Arizona is the equivalent of several distinct faunal 

zones in rocks of Frasnian age in Alberta. No closer 

comparisons can be made at this time. 

The upper part of the Martin Formation is stratigraphically broadly equivalent to the Mount Hawk Formation and the Nisku Formation of central Alberta, and 

it may include equivalents of part of the Alexo Formation. 

Underlying the Nisku is the Ireton Formation (or 

Ireton Shale Member of the Woodbend Formation), 

from which Loranger (1954, p. 202) described and illustrated an ostracode under the name of Kloedenella sp. 

This ostracode, according to Jean Berdan (written communica:tion to C. A. Sandberg, 1960), is possibly identical with those identified as H ypotetragona sp. from the 

upper part of the aphanitic dolomite unit of the Jerome 

Member of the Martin. It may be of some significance 

that in Alberta, as well as in Arizona these ostracodes 

occur stratigraphically below beds for which general 

correlation has been determined on the basis of their 

coral and brachiopod faunas. 

More exact correlation of biostratigraphic zones and 

of rock-stratigraphic units must await a more detailed 

study of Devonian faunas from all parts of the Rocky 

Moruntain province. 

SUMMARY OF FACIES PATTERN AND 

PALEOGEOGRAPHY 

COMMENTS ON SECTIONS 

The facies pattern of the Devonian rocks of the area 

can be read from plates 28-31, on which the numbered 

stratigraphic columns have been arranged according to 

nine lettered cross sections. In the following paragraphs, comments are offered on each section; but ~­

cause the graphical representation of each stratigraphic 

column conveys in a comprehensible manner information on lithology, bedding, color, grain size of both 

carbonate and siliceous-detrital rocks, and a detailed 

analysis of faunal content, the sections are mostly selfexplanatory. 

SECTION A-A' 

Section A -A' (pl. 28) presents several interesting features. The Beckers Butte Member varies considerably 

in thickness owing to intensive channeling in the Canyon Creek area (section 8) . Field evidence suggests 

that from sections 6 through 8 and to Huddle and Dobrovolny's Cliff House Canyon section, the section is 

along a deep channel of the Beckers Butte Membe-r. 

Outside the channel the Beckers Butte is a continuous 

sheet 10-20 feet thick. At the northwest end of the section, in the Spring Creek area, the Beckers Butte Member and the two lower units of the Jerome Member 

wedge out toward the Defiance uplift. 

The fetid dolomite and the aphanitic dolomite units 

of the Jerome Member are present from the Black River 

to Cliff House Canyon. The fetid dolomite unit varies 

little in thickness; the aphanitic dolomite unit thins 

slightly to the northwest. Generally, throughout the 

entire area of its distribution, the aphanitic dolomite 

unit is uniformly composed of thin- to medium-bedded 

generally light-colored aphanitic dolomite, although 

lenses of sandstone occur locally. Fossils are scarce 

and include brachiopods, indeterminable ostracodes, and 

calcispheres. 

The upper unit of the Jerome Member is composed of 

many facies and has many changes in appearance from 
ROCKS OF THE MARTIN FORMATION 93 

one end of the section to the other. In the southeast 

(Black River, section 2), it is predominantly clastic; 

it consists of sandstone at the base and is overlain by 

dolomite that grades upward into dolomitic limestones 

and fossiliferous calcareous siltstones at the top. 

The upper unit thickens toward the northwest. The 

upper shale-siltstone facies, however, thins in the same 

direction and becomes unfossiliferous. The middle, 

dolomitic part thickens and grades into a mixed sandstone-carbonate facies in which limestone increasingly 

predominates over dolomite to the northwest. This 

part of the unit is also increasingly fossiliferouS' 

northwestward. 

The lowermost sandy part of the upper unit of the 

Jerome is composed of a sandstone-shale facies to the 

northwest, which wedges out into a moderately pure 

carbonate-predominantly dolomite-facies; the facies 

is purest and thickest in section 8. The lower part of 

the sandstone-shale facies changes to pure sandstone to 

the northwest near the edge of the Defiance uplift. 

In places, a thick biostromal unit separates the lower 

dolomite facies from the upper mixed sandstone-carbonate facies. 

SECTION B-B' 

The five measured sections are not fully comparable, 

because the entire Jerome Member is represented in only 

two of them (sections 3 and 46) . Section B -B' (pl. 28), 

however, is of interest because it illustrates the approximate northerly trends in facies distribution. 

The Beckers Butte Member thickens greatly from 

section 3 1to section 5. The sandstone fills a channel and 

for the most part is very coarse to conglomeratic. This 

channel is possibly a continuation of the channel shown 

in sections 6 and 8, and it possibly continues southeastward into the area of section 47. If so, it is continuous 

for more than 20 miles. 

The Jerome Member is considerably attenuated to the 

south. Section 46, at Sevenmile Creek, has the smallest 

thickness of Jerome measured anywhere in the area 

studied. The attenuation affects the aphanitic dolomite 

unit and the upper unit but not the fetid dolomite unit. 

A significant component of terrigenous materialsandstone, siltstone, and shale-is found in all sections; 

the material occurs in varying proportions and at different stratigraphic levels. The general distribution of 

these terrigenous sediments suggests a northeastern, 

eastern, or southeastern source area. Some of these sediments came probably from the Defiance uplift in the 

northeast; others came from a southeastern source having a yet unknown exttmt and location. (See also discussion of sectionH-H' on page 95.) 

SECTION C-C' 

Section 0-0' (pl. 29) is approximately at right angles 

to the isopach lines and therefore, is of particula.r importance. It extends from the area of nondeposition of 

the fetid and aphanitic dolomite units in the northeast 

into the edge of the basin where the Jerome Member is 

thickest. 

Sections 10 and 11 are on the edge of the Defiance 

uplift, where the Beckers Butte Member and the fetid 

and aphanitic dolomite units of the Jerome Member are 

missing. The upper unit of the Jerome is thin and 

contains intercalated sandstone. The carbonate unitshere mostly limestone-are richly fossiliferous. 

A great change in thickness occurs within a distance 

of only 4 miles between section 10 and section 12. To 

emphasize this change, sec.tion 45, about 2112 miles north 

of the line connecting sections 10 and 12, has been projected to the line of section to illustrate the gradual 

thickening of the upper unit of the Jerome Member 

west of section 10. Section 45 does not contain any true 

biostromal facies, although stromatoporoids do occur 

abundantly at a stratigraphic level approximately 

equivalent to the levels of the biostromes in sections 10, 

11, 12, and 13. 

At section 12 both the Beckers Butte and Jerome 

Members are complete. The Beckers Butte is 83 feet 

thick here and may have been deposited in the large 

channel exposed in sections 5, 6, and 8; if so, the channel 

is 30 miles long. 

Both the fetid and the aphanitic dolomite units of the 

Jerome Member are typically formed at section 12. The 

aphanitic unit, however, is only 71 feet thick and has 

a few sandstone interbeds in its lower part, indicating 

that it was near the wedge edge of deposition. 

Not only the fetid and aphanitic dolomite units but 

also the lowe~ two-thirds or more of the upper unit 

wedge out between sections 12 and 10. In section 12 

the basal part of this unit is composed of sandstone 

and very sandy dolomite, which indicates that the section is near the onlap of the upper unit over the Precambri;an basement. 

The sandstone is overlain by dolomite containing 

rugose corals and Amphipora. Two biostromal units 

(34 and 37) that are still higher in the section are probably the equivalent of the biostromal subunit 2 in section 10. In both sections 10 and 12, they are overlain 

by sandstone, as in sections 13 and 11. The upper part 

of the upper unit of the Jerome Mmnber is uniformly 

fossiliferous from the biostromal subunits upward; 

brachiopods are abundant in all sections. . 

Important differences between sections 12 and 13 are 

the absence of a basal sandstone in the upper unit to 

the west and the indication of a slightly greater thickness of the aphanitic dolomite unit in the same direction, although the unit is not fully exposed in section 13. 

SECTION D-D' 

Section D-D' (pl. 29) illustrates the units near the 

wedge edge of the aphanitic dolomite unit of the Jerome 
94 DEVO~AN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

Member. The three sections (14, 15, 16) are arranged 

approximately at right angles to this edge. Only the 

lower 25 feet of section 16 probably constitutes the 

aphanitic dolomite unit, which here has a basal 

sandstone. 

The section also shows the onlap of the upper unit 

over the Precambrian base just outside the wedge-out 

line of the fetid and aphanitic dolomite units. Considerable thinning occurs between sections 16 and 14-

from 197 feet to 75 feet. At section 16 the upper unit, 

except for a basal sandstone, consists almost entirely of 

carbonate rocks. Sections 14 and 15 also have basal 

sandstones but are considerably more sandy throughout. 

The channel at the base of section 14, which is mostly 

filled with finely to medium-crysta.lline sandy dolomite 

rock, is of special interest. Evidently, in this area some 

relief existed almost to the end of sedimentation in 

Devonian time, but filling of· this particular channel 

(or depression) took place when, or 'at a place where, 

little clastic detrital material was available. Generally, 

less clastic material was available in this ~area than in 

similar sltra.tigraphic positions to the west and to the 

east. The "channels" in this area· were probably shallow,-panlike depressions. (Seep. 50.) 

· The uppermost 35 or 40' feet of all three sections are 

uniformly fossiliferous, although sandiness increases 

from south\vest to northeast. 

SECTION E-E' 

Section E-E' (pl. 29) illustrates the somewhat 

anomalous slight thickening of the aphanitic dolomite 

unit from south to north in the direction of the wedge 

edge. However, correlation of the bottom part of both 

sections is somewhat arbitrary, as no truly aphanitic 

rocks but only fine-grained dolomite having a subconchoidal fracture occur. 

The upper unit thickens slightly from north to south, 

a way from the wedge edge, and the unit in the more 

northern section (No. 17) seems to contain more 

siliceous-detrital material. A true sandstone and silt 

facies exists only in the uppermost part of section 17 

(Colcord Canyon), where the clastic beds are interbedded with limestone. In the southwestern section 

(No. 18), clastic material is absent from this part of 

the unit, but one limestone bed remains. In both sections fossils are restricted to this uppermost calcareous 

and clastic facies. 

SECTION F-F' 

The important section F-F' (pl. 29) traverses Christopher Island and illustrates the general onlap of both 

the aphanitic dolomite and the upper units of the 

tTerome Member. The wedging out of the aphanitic 

dolomite unit at its northwestern end towards the uplift 

is well illustrated, as is the abrupt northwesterly thickening of the upper unit away from the uplift. The 

aphanitic dolomite unit contains a significant clastic 

component. 

At the southeastern end of the cross section (section 

18, south of Turkey Peak), the entire upper unit is 

dolomitic. Northwest toward Chistopher Island, an 

increasing· amount of siliceous detrital material was 

introduced. The aphanitic dolomite unit is missing 

everywhere along the southwest side of the uplift, and 

sandstone or dolomite of the upper unit rests directly 

on Precambrian (mostly Mazatzal) Quartzite. 

On the northwest side of the high area, the mixed 

sandstone carbonate facies persists and here constitutes 

the uppermost part of the upper unit of the Jerome 

Member. It is underlain by an abruptly thickening 

unit composed of pure dolomite, and near the bottom 

of the unit dolomite is interlayered with clastic 

sediments. 

In the area within about 3 miles of Christopher 

Island, the rocks are unfossiliferous, but beyond this 

area normal brachiopod and coral associations, together 

with other fossils, are present in the higher parts of 

the sequences. 

On the west side of Christopher Island, the aphanitic dolomite unit probably reappears at Kohl Ranch 

(section 28), where it is composed of sandstone and 

fine-grained dolomite (subunit 4) totaling 15 feet in 

thickness. The unit seems to thicken to the north, for 

in section 27 (junction of Tonto and Horton Creeks) 

an aphanitic dolomite (subunit 6) underlain by sandstone and conglomerate has possibly a. total thickness 

of 55 feet. Here as elsewhere near the wedge edge, the 

rocks of the fetid and aphanitic dolomite units change 

facies and include so much siliceous detrital rock that 

they are no longer clearly recognizable on the basis of 

typical lithology. Also, the basal part of the upper 

unit includes sandstone, and the distinction between 

sandstone facies of the various units is impossible to 

make. 

Even though some details of correlation of the basal 

parts of these sections can only be decided arbitrarily, 

it seems certain that none of the basal clastic rocks 

belong to the Beckers Butte Member. Apparently, the 

area shown by the section furnished some of the sedimentary material for the Beckers Butte Member. 

SECTION G-G' 

Section G-G' (pl. 30) illustrates the lithology and 

the facies changes west and southwest from Christopher 

Island. At Kohl Ranch (section 28) -and Thompson 

Wash (section 29), the fetid dolomite unit of the Jerome 

Member and the Beckers Butte Member are missing, 

and the aphanitic dolomite unit of the Jerome is entirely composed of a sandy facies that becomes more 
ROCKS OF THE MARTIN FORMATION 95 

silty in its upper part with increasing distance :from 

the high area. At Thompson "\V ash the sandstones are 

in part hard, massive, very crossbedded, and replete 

with fragmental fish plates. 

Further west the typical aphanitic dolomite facies 

reappears, although the general composition of the unit 

is still somewhat inhomogeneous. In addition to typical 

aphanitic dolomite, intercalated sandstone beds and 

some beds of limestone and slightly dolomitic limestone 

occur. 

The upper unit of the Jerome Member has the same 

thickness, but details of the lithology of the member 

near the East Verde River are not yet sufficiently well 

understood, mostly because exposures are unsatisfactory. However, a lower carbonate (largely dolomitic) 

:facies that is un:fossili:ferous can probably be distinguished from an upper mixed clastics and carbonate 

facies that consists of erratically distributed sandstone, 

siltstone, shale, limestone, and dolomite, some of which 

are richly :fossiliferous. 

SECTION H-H' 

Section H-H' (pl. 30) traverses an a,rea of very 

complex lithology, the complexities of which cannot be 

accurately portrayed. It crosses Pine Island, on which 

no Devonian rocks were deposited and where the Redwall Limestone rests on Dripping Spring Quartzite. 

However, within a distance of as little as Ilf2 miles east 

of Pine Island (at section 33), both the Beckers Butte 

and the Jerome Members are typically :formed; the 

three units of the Jerome have normal thickness. 

The Beckers Butte Member in this area has the characteristic intercalations of sandy dolomite in the upper 

part. 

The :fetid dolomite unit of the Jerome is thin east of 

Pine Island and absent at Tonto Natural Bridge, where 

the Beckers Butte also is missing. 

The aphanitic dolomite unit is present in all sections; 

however, except for the section at Limestone Hills, 15 

miles to the southwest, the unit is much less homogeneous than elsewhere. Some of the dolomite of the 

aphanitic unit shown in the section is more calcitic than 

is common for these rocks; at Tonto Nat ural Bridge 

intercalations of sandstone and a conglomeratic base are 

found, indicating that this member here transgresses 

an irregular Precambrian basement. Tonto Natural 

Bridge is also one of the :few places where :fossils (calcispheres and ostracodes) are :found in the aphani,tic 

dolomite unit. They occur only in calcareous or slightly 

dolomitic beds, and their presence indicates that the 

unit here is near the south side of Pine Island, where 

normal marine sedimentation existed. 

The upper unit of the Jerome has a significant clastic 

component near Pine Ridge that, however, diminishes 

and disappears toward the southwest. Sandstone characterizes the middle part, or beds somewhat above the 

middle, of the unit. The remainder is a fairly pure 

carbonate :facies- in which the limestone-d-olomite ratio 

generally shifts towards predominating dolomite :from 

northeast to southwest, and at Limestone Hills (section 

38) the upper unit is almost entirely dolomitic. 

Fossiliferous horizons are --scattered· through the 

upper unit, but most :faunas are small and poor: 

SECTION I-I' 

Section I -I' (pl. 31) extends for more than 150 miles. 

Its greater part, from Pinal Creek (section 35) to the 

Verde River at Sycamore Creek (section. 43), exte~ds 

north westward in an almost stra~ght line. Between 

Theodore Roosevelt Dam (section· 36) and Limestone 

Hills '(section 38), it crosses the hypothetical Ma;;mtzal 

Land and toughly parallels the southwestern edge o.:f the 

Defiance uplift. · 

The facies pattern along this entire section is rather 

uniform. The Beckers Butte occurs as thick channel 

fill both at Theodore Roosevelt Dam and at Limestone 

Hills. Along the southeastern part of the ·section, the 

Beckers Butte is not exposed. Northwest of the Limestone Hills; the Beckers Butte is still clearly present at 

Chasm Creek and Squaw -Peak; whereas, sandston~s in 

an equivalent stratigraphic position in the Jerome area 

compose the Cambrian Tapeats Sandstone rather than 

the Beckers Butte. (See discussion on p. 26-27.) 

The fetid dolomite unit of the Jerome Member is 

uniform in lithology from the Roosevelt area as :far 

as Jerome and is generally uniform in thickness, having 

only a local thickening to 40 feet at Chasm Creek 

(section 39). 

The aphanitic dolomite unit thickens somewhat :from 

the Roosevelt area to the Limestone Hills. From here 

westward it seems to have a consistent thickness of 

slightly less than 150 feet. It is noteworthy that in the 

entire distance illustrated by the section, siliceous 

detrital rocks are subordinate in this unit. In the 

Jerome area only the "red marker bed" of Anderson 

and Creasey ( 1958) occurs, which is a highly dolomitic quartz sandstone, and is 2 feet thick; a similar 

bed is :found in the Windy Hill section ( 37) . The 

aphanitic dolomite unit, then, is remarkably uniform 

along the entire area and is composed almost entirely 

of typical aphanitic dolomites and thin shaly interbeds, 

which are found especially in the lower part. 

Similarly the upper unit is rather uniform in facies 

pattern. At Theodore Roosevelt Lake the unit has a 

significant siliceous detrital component and has a mixed 

dolomite-sandstone :facies except for the upper 60 feet, 

which has a sandstone-shale facies. This upper facies 

thickens considerably southeastward and is 110 feet 

thick at Pinal Creek (section 35, subunits 20--26), 
96 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

where it also is much more fossiliferous. Brachiopod 

faunas (atrypids and Devonoproductus) are dominant. 

A comparison of the section at Theodore Roosevelt 

Dam (No. 36) with that at Windy Hill (No. 37) 

indicates that the distribution and lateral extent of 

individual rock subunits of the mixed dolomite-sandstone facies are apparently very irregular. Although 

only 41;2 miles apart these two sections are not closely 

similar in the order of succession of carbonate and sandstone subunits. However, in both localities a marked 

concentration of fossiliferous beds occurs in the middle part of the facies. 

The mixed dolomite-sandstone facies thins towards 

the southeast. At Pinal Creek it is only 96 feet thick 

and consists of about half dolomite and half siliceous 

detrital clastics (which here include siltstone). All 

carbonate subunits and some sandstones are highly 

fossiliferous. 

In the northwestern part of the area, the upper unit 

is less complex and in fact is composed of an almost 

pure dolomite faeies, 1nost of which is poorly fossiliferous. Obviously this area was far from the sources 

of terrigenous materiaL The great variety of dolomitic 

rocks that characterize this area is described on pages 

42 and 43. The unit thickens to the northwest from 218 

feet at Limestone Hills (section 38) to 307 feet at Jerome 

(section 41). In section 43 (Verde River at Sycamore 

Creek) one shale subunit (24) occurs above the middle 

of the unit, and a thin sandstone subunit is found at 

the top. Fossil horizons are few and widely separated 

although ric£. assemblages occur locally. 

The isolated Elden Mountains section (No. 44) is included in the section in order to show its close lithologic relation with the upper unit of the Jerome Member in the Jerome area. 

PALEOGEOGRAPHY 

Much evidence derived :£rom the study of facies distribution and the isopach pattern of the rocks of the 

Martin Formation in central Arizona indicates that the 

Martin was deposited ,first on land (Beckers Butte) and 

then in gradually deepening water on a slo,vly subsiding, broad shelf to the southwest and west of the 

Defiance uplift ; the evidence also indicates the absence 

of any ancient landmass in the area. These conclusions 

are based on ( 1) the areal distribution of the Beckers 

Butte, (2) the distribution and facies character of the 

fetid and aphanitic dolomite units of the Jerome 1\imnber, ( 3) the lateral distribution of terri crenous siliceous 

d . b 

.etr1tal material in the upper unit, and ( 4) the distributiOn and composition of fossil faunas in the upper part 

of the uppe'r unit. 

The rocks of the fetid and aphanitic m1its were 

formed by rather special combinations of sedimenta.-

tional and diagenetic processes. The uniform thickness 

and lithologic character of these rocks and their wide 

distribution southwest ,and west of the Defiance uplift-from the Jerome area in the north west as far as 

Globe. and the Black River area. in the southeastindicate that conditions of sedimentation across this 

very large area were uniform. 

Separation of the sea located in the present a,rea of 

Jerome and the Upper Verde River from that located 

in the present upper Salt River area by a land barrier, 

as envisaged by Stoyanow ( 1942, pl. 5, fig; f) , or even 

the existence of a substantial landmass in the general 

area would be reflected by facies differentiation that 

should be decipherable from the present rock record 

despite widely spaced outcrops. More especially, a 

significant silieeous-detrital component might be expected in the two lower units of the Jerome Member 

at Limestone Hills and at Theodore Roosevelt Dam 

because these localities are close to or possibly within 

the former shorelines on opposite sides of the supposed 

land, as shown by some authors. Instead, the sections 

(Nos. 36, 38) at both localities are very much alike and 

the fetid and aphanitic dolomite units lack significant 

amounts of terrigenous detrital 1naterial. The fetid 

dolomite unit is very similar in lithology and in thickness-20 feet at Theodore Roosevelt Dam, 21 feet at 

Limestone Hills-at both localities.. 

The aphanitie dolomite unit is 102 feet thick at Theodore Roosevelt Dam and 155 feet at Limestone Hills, 

but the general lithology is the same. At Theodore 

Roosevelt Dam the unit consists entirely of aphanitic 

and subaphanitic dolomite that contains no more detrital quartz than is found in the normal faeies of this unit. 

(See description of subunits 11 :and 12 of section 36.) 

Four and a half miles farther east at Windy Hill (section 37), a 4-foot sandstone bed occurs 15 feet below 

the top of the aphanitic dolomite unit. This occurrence, too, is not unusual, and the stratigraphic position of this sandstone unit corresponds approximately 

to that of a similar sandstone bed in the Jerome section 

(section 41, subunit 13). 

At Limestone Hills (section 38) as much of the aphanitic dolomite unit, as is exposed consists entirely of 

dolomite rock and only seattered detrital quartz. 

Notwithstanding the 48-foot covered interval, it is 

unlikely t.hat a sizable sandstone sulbunit is hidden here, 

because no sandstone was noted in the talus and because 

the entire section at Limestone Hills, including the upper unit, eonsist.s of a rather pure carbonate facies. 

Not only does the facies distribution in the fetid 

and aphanitic dolomite units seem to be irreconcilable 

with the assumption of a Mazatzal landmass in Devonian time, but also the distribution of terrigenous siliceous detrital material in the upper unit of the Jerome 
ROCKS OF THE MARTIN FORMATION 97 

Member opposes such an assumption. Both at Theodore 

Roosevelt Dam and at Windy Hill, the upper unit has 

a significant component of sandstone. The ratio of 

sandstone and shale to carbonate rocks at Theodore 

Roosevelt Dam is 12: 13; at Windy Hill, 16: 14. Total 

thickness of sandstone and shale in the upper unit is 

123 feet at Theodore Roosevelt Dam and 163 feet at 

Windy Hill. The general impression that these clastics 

came from an eastern or southeastern (rather than wesltern) source is also supported by the complete absence 

of sandstone in the upper unit at Limestone Hills (section 38), although many dolomite and limestone subunits contain appreciable amounts of detrital quartz. 

Stoyanow (1942, pl. 5, map f) showed occurrence of 

widespread arenaceous facies northwest of the poshilated northwestern shore of Mazatzal Land and north 

as far as Jerome and Elden Mountains. Such a sandy 

facies has been shown to be nonexistent. 

The general picture of facies distribution in the 

upper unit illustrated by section /-/' (pl. 31) suggests 

an area of uniform deposition in which the supply of 

clastic terrigenous material lessened from southeast to 

northwest and ceased to be significant at some unknown 

distance northwest of the Roosevelt area. Published 

reports (Huddle and Dobrovolny, 1952; Peterson, 

1954) indicate that terrigenous rocks are significant 

also south of the Roosevelt area. Thus, at Superior 

the ratio of clastics to carbonate rocks is 2: 3, and at 

Gold Gulch, northwest of Castle Dome mine, it is about 

1: 2. Peterson reported a middle quartzite unit from 

the Globe quadrangle 10-35 feet thick tha;t seems to correspond to the lower pa.rt of the upper unit as defined 

in this report. The upper shale zone is reported also 

from the Globe quadrangle. 

The Devonian rocks in the area east and south of 

Globe have not yet been studied in sufficient detail to 

allow paleogeographical conclusions. In the Globe 

quadrangle, the thickness of Devonian rocks, according 

to Peterson (1954), ranges from 150 to 350 feet. At 

Sevenmile Creek (section 46) the entire Jerome is only 

252 feet thick, and the considerably attenuated upper 

unit contains a significant terrigenous component. 

The distribution of terrigenous material in the upper 

unit in the area east of Theodore Roosevelt Dam suggests the presence of a source area to the east rather than 

to the west. 

Along the north and northeast shores of Mazatzal 

Land drawn on rna ps, the amount of terrigenous clastics 

is observed to have decreased with increasing thicknesses of deposits from southward or southwestward. 

Facies and isopach patterns of the member agree well 

with these observations. Sections 0-0', D-D', E-E', 

and G-G' should be noted especially, as all show that 

siliceous-detrital material in the upper member decreases southward or southwestward. 

Finally, the unifonn distribution and composition 

of marine invertebrate faunas in the upper part of the 

upper unit indicates ecologic conditions were uniform 

in the area southwest of the Defiance uplift. The wellpreserved thanatocoenotic associations and little-transported brachiopod coquinas indicate nonturhulent conditions during the closing stages of the deposition of the 

Martin Forma.tion, rather than nearness of rocky 

shores. 

All facts thus point toward the conclusion that the 

sea covered the area between the Salt and Verde Rivers 

now occupied by the Mazatzal Mountains and the Sierra Ancha at all times during the deposition of the 

Jerome Member (fig. 37). Conflicting views regarding 

the paleogeography of central Arizona in Devonian 

time have thus been resolved, and the paleogeographic 

picture that was drawn on the basis of broad generalizations by Eardley (1951) and by McKee (1951) is, in 

its essential outlines, supported by detailed facies and 

isopach studies. 

The absolute duration of the Late Devonian Epoch 

has been determined to be about 20 million years. If 

one considers the fact that the Jerome Member is most 

probably equivalent to only one of the six Upper Devonian goniatite zones, the total time required for the 

deposition of the Jerome should have been3 or 4 million 

years. This is a time span equivalent to the duration 

of one-third or one-fourth of the Pliocene. The value 

is reasonable and allows for the time required for the 

accumulation of the sediments in the presence of slight 

negative epeirogenetic movements. 

MICROFOSSILS OF THE JEROME MEMBER 

Whereas the megafauna of the Jerome Member consists of relatively well known genera, many assemblages 

of microfossils from the Jerome have not been previously reported; these microfossils are important in the 

microfacies of the Devonian rocks in the Rocky Mountain province. The microfossils are described and illustrated here in order to call attention to their existence 

and to stimulate search for them elsewhere. 

TINTINNIN A. (?) 

Until recently no tintinnids older than Late Jurassic 

were known (Campbell, 1954), but Cuvillier (1957) reported the presence of representatives of the group in 

limestones of Late Devonian age in the Sahara (Algiers) 

and southern France (Languedoc). These forms have 

not yet been described in detail. In view of this discovery attention should be called to possible occurrence 

of tintinnids in the Jerome Member of Arizona. 

Small thin-walled shells that resemble tintinnids 

occur in limestone in upper Colcord Canyon (section 
200' 

100' Christopher Island 

0 

100' I I I I I I I I I I I I I I I I I I I I :P..:,;;.;<:zi:-:E::·----~~ 

200' --J I ' I ..-Go:=-': J?Ti:· .... I ~ I I :!:8. ·.>"'.·-~::_::::::;:~ 1 ~< ;:z < /~~_. I I I ,I J I I I 300' I 

400' 

500' 

600' 

700' 

:.Jf/;:e~=~b~~tte 

' Aztek Peak ~~~ 1/;Ca:~n Creek7/f I 

channel I / nnel I / ; j//111 j; 

200' 

100' 

0 

100' 

200' 

300' 

Carbonate rocks; pre- Shale 

dominantly dolomite 400' 

500' 

600' 

Biostromes Sandstone 

700' Christopher Island, projected into line of 

section, is indicated by dashed line 

800' . 800' 

Vertical exaggeration x 165 

0 10 20 30 MILES 

FIGURE 37.--,Sectlon from near Holbrook to near Theodore Roosevelt Lake, showing stratigraphic relations at the time of the close of deposition of the Martin Formation. 

co 

00 

t:::l 

ts:l 

~ ~ 

~ 

0 

~ rJ). 

~ 

~ ts:l 

0 

§ 

0 

0 

~ 

~ 

~ 

0 

l'!lj 

~ 

~ ~ 

E= 

Ed 

1-4 

N 

0 

~ 
ROCKS OF THE MARTIN FORMATION 99 

17) at 177 feet above the base of the Jerome. The limestone is made up of extremely fine grained biogenic 

material. 

These forms (pl. 16, fig. 2) are thin walled and cup 

shaped and have a rounded bottom and a slightly flaring aperture. They are about 0.6 mm long, 0.45 mm 

in maximum width, and about 0.35 mn1 across at the 

aperture. In shape they resemble somewhat the genus 

T-intinnopsella, known from the Late Jurassic and Early 

Cretaceous of Europe (Campbell, 1954, p. D173), which, 

however, is considerably smaller. 

Another form was found in a limestone 245 feet above 

the base of the Jerome in Salt River Draw (section 6). 

It is bell shaped and has a pointed base; the entire 

skeleton is 0.5 mm long and 0.35 mm wide in the middle. 

The aperture is slightly constricted (pl. 16, fig. 1). The 

form resembles some members of the family Ptychocyclididae. (See Campbell, 1954, p. D175.) 

Mesozoic tintinnids do not generally exceed about 0.3 

mm in length and most of them are smaller ( Colom, 

1948) . The forms described above are about twice the 

size of the larger Mesozoic forms. More data are needed 

before they can be classified with greater confidence. 

CALCISPHERES 

Many limestones contain abundant hollow spheres 

that have calcitic shells and range in size generally from 

less than 0.1 mm to 0.5 mm. Several different morphological types can be distinguished. 

Williamson ( 1881) was apparently the first to describe fossils of this kind, to which he gave the formal 

generic name 0 alcisphaera. He distinguished several 

morphologically distinct forms as different species, 

which with one exception came from marine limestones 

of Early Carboniferous age in North Wales. The exception was a compa.ratively large form from marine 

limestone of Middle Devonian age from Ohio, to which 

Williamson gave the name Oaloisphaera robusta. 

Miller ( 1889) designated this species as the type of 

Oalcisphaera, but Andrews (1955, p. 123), Horn af 

Rantzien (1956, p. 245), and Konishi (1958, p. 103) be.-

lieved that this choice was erroneous; Andrews and 

Konishi suggested that Oalcisphaera laevis Williamson 

should serve as the type species. This species had been 

made the type of a new genus Granu.losphaera hy Derville (1931, p. 132), who later recognized, however, that 

Granulosphaera and 0 alcisphaera should be considered 

synonyms (Derville, 1941). Oalcisphaera la,evis, occurs in limestone of Carboniferous age in North Wales 

and is reported by Derv1lle ( 1931) from marine limestone of the same age in France. 0 alcisphaera robusta 

was shown by J{arpinsky (1906) to be a charophyte, a 

classification that has been confirmed by later investigators (Hacquaert, 1932; Peck, 1934). 

After publication of Williamson's paper, microscopic 

caleitic spheres were found in many Paleozoic rocks, 

chiefly those of Devonian and Carboniferous age. The 

morphological variety of the spheres is considerable, as 

is shown by the large number of separate genera that 

authors have attempted to separate from the original 

genus Oaloisphaera. Among these are Granulosphaera, 

Oytosphaera, Diplosphaera, and Polyderma of Derville 

(1931, 1950), Bisphaena and Praechara Birina (1948), 

and Radiosphaera, Asterosphaera, Ra,di-ina, and Sphaerella of Reitlinger ( 1957), though some of these genera 

may be Fora1ninifera. 

Beeause of considerable uncertainty as to the taxonomic affinities of these objects, many authors refer 

to them informally as calcispheres (French calcispheres; German, Calcispharen). This usage seems 

preferable to establishment of a formal family (such 

as Calcisphaeridae Miller, 1889) or higher taxon, and 

the term is here used for all primarily hollow, more or 

less spherical calcitic bodies of microscopic size. These 

bodies vary mainly in size and in thickness and structure of their encasing wall. J{onishi (1958, p. 108) demonstrated that the appearance of this wall may vary 

considerably owing to diagenetic changes. 

Calcispheres of Devonian age from the following 

regions have been mentioned or described: Germany 

(Chapman, 1921), Belgium (Lombard and Monteyne, 

1952), France (Mil on, 1923, 1928; Le Maitre, 1930), 

Alberta (Beales, 1956, 1958; J{onishi, 1958), the VolgaUral region (Bykova and Polenova, 1955), the Russian 

Platform (Birina, 1948; Rakhmanova, 1956; Reitlinger, 

1957), and northwestern Australia (Veevers, 1959, p .. 

18). Calcispheres of Carboniferous (mostly Early Carboniferous) age from marine rocks in the following regions have been described: England (Reynolds, 1921; 

Wolfenden, 1958; and others), Germany (Paul, 1937), 

France (Derville, 1931, 1950, 1952; Lapparent, 1923), 

the Donetz Basin ( Botvinkina and others, 1956) , Japan 

(Konishi, 1956), and more recently the United States 

(Baxter, 1960). 

Tiny spherical fossils, resembling the Paleozoic calcispheres, are also known from rocks of Mesozoic age. 

Among these are the following: Fibrosphaera from 

Cretaceous roeks, described by Lapparent (1924; see 

also Colom, 1931); Oadosina and Stomiosphaera, which 

were first described from Jurassic rocks of Indonesia 

by Wanner (1940) and since recognized in the Bavarian 

Alps (Hagn, 1955) and in Morocco (Colom, 1955) and 

which have a fibrous wall structure as demonstrated by 

Leisehner (1959, p. 870); and OaZcisphaerula, which 

was described by Bonet ( 1956, p. 44) from the Cretaceous of l\1exico, Texas and from the Mediterranean 

area and which cannot be distinguished from the Paleozoic Oalcisphaera, according to Bonet. Finally, from 
100 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

the Pierre Shale of Late Cretaceous of Colorado, LeRoy 

and Schieltz (1958, p. 2453) described "microspheres" 

having the same general appearance. 

Attempts to separate morphological groups of calcispheres according to wall structure have been made by 

Derville (1_941) and Reitlinger (1957). Konishi (1958, 

p. 103) P?Inted out that apparently objects belonging 

to three different groups of organisms had been referred 

to as calcispheres: (1) certain trochilisks such as 

"C l ' ' ,a ~zsphaer~, rob:',sta"; (2) organisms of the type 

described as calcispheres de forme A" by Lombard 

and. Monteyne (1952, p. 14-16) ; and (3) the "typical 

calcispheres" of unknown biologic affinities. To o-roup 

1 belong the "calcispheres de forine C" of Lombard and 

Monte~ne (1952, p. 16-17), who apparently did not 

re~og~Ize ~he ch~rophyte affinities of the form. Group 

3 1s Identical with Lombard and Monteyne's "calcispheres de forme B." 

. Group 1 is not discussed here because no representatives were found in Devonian rocks of Arizona. The 

organisms constituting group 2 belong to the genus 

Vmbella Maslov, which occurs sparingly in the .Jerome 

Member. The "typical" calcispheres, group 3, are 

abundant in Arizona Devonian rocks and are discussed 

first. 

The group 3 calcispheres that occur in the Jerome 

may be divided into thin-walled and thick-walled types. 

T~e walls o~ the ~hick-walled type may be secondarily 

tlnnned during dmgenesis, but the two types of shells 

are also distinguished by size-the primarily thinwalled forms are smaller than the thick-walled ones. 

THIN-WALL ED CALCISPHERES 

Several limestone beds of the upper unit contain large 

numbers of tiny calcareous spheres that are of 

two sizes. A representative rock is shown in plate 17 

~gure 2; the slide contains very many sections of verlr 

tiny spheres and a few of distinctly larger ones. 

The very small sections are very generally circular, 

or nearly so, and their dia1neter does not exceed 100 

micro.ns. Th~y, therefore, represent almost perfectly 

sphencal bodies having a maximum diameter of about 

10.0 microns. About half of the tiny spheres are filled 

\VIth aphanitic limestone matrix and half are filled . ' :Yith cry~talline calcite. The shell of the hollow spheres 

Is 3-5 microns thick. 

In a~other rock (pl. 18, fig. 1) the same kind of 

sphere Is abundant, but the spheres are associated with 

A~nphip~ra. In another rock type the spheres are 

1n1xed with a large amount of very fine fossil debris,--

pteropods, ostracodes, and unidentified material (pl. 17, 

fig. 1)-but many of them can be clearly distinguished. 

THICK-WALLED CALCISPHERES 

Thick-walled calcispheres are larger spherical or 

near-spherical objects having diameters greater than 

200 microns and comparatively thick shells that have 

a recognizable fibrous texture where well preserved. 

Spheres of this category are of two types: one in which 

the shell encloses a perfect hollow sphere and another 

in which the internal hollow space is elliptical. The outside of the shell of both types is more or less irregular. 

Type 1 includes all those forms that are closely 

similar to Oalcisphaerra fimbriata and 0. hexagonata 

Williamson (1880, p. 521-522) and to the "fombriata 

type" of Konishi (1958). 

Very typical specimens of this kind make up a large 

proportion of some originally aphanitic but highly 

recrystallized limestones in the upper unit of the Jerome 

Member (pl. 19). 

The rock illustrated in plate 19, figure 1 superficially 

appears "pelletal." The "pellets" of aphanitic limestone, however, which vary greatly in size, are obviously 

parts of the rock that have escaped recrystallization. 

That the clear crystalline "cement" originated through 

grain growth from finer grained probably aphanitic 

limestone is shown by the fact that it entirely surrounds 

many calcispheres. 

The calcispheres have external diameters as much as 

and perhaps slightly exceeding 200 microns and internal 

diameters as much as about 150 microns. Most spheres 

are embedded in the crystalline cement, and nearly all 

shells are affected by recrystallization. Where recrystallization has been extreme, the shell is completely 

replaced by crystalline calcite and is no longer recognizable (pl. 19, fig. 1). All transitions in replacement 

occur : from shells in which recrystallization has been 

extreme to shells whose outlines are still well preserved 

and that have retained the original fibrous texture. 

Most commonly, only part of the shell was absorbed 

by the calcite, and the remnants of shell merge into the 

surrounding calcite along a fuzzy margin (pl. 19, fig. 

1B) , but some specimens apparently retain their original outline (pl.190, fig.1). 

The inside of the fibrous shell is lined with -a dark 

film. Although the lining has been observed by many 

authors, especially in calcispheres having fibrous shells, 

its 1nineralogical nature has not been determined. -

All spheres are filled with clear crystalline calcite 

that probably resulted from diagenetic infiltration. 

As grain growth proceeded in the rock, the greater 

part of the rock came to consist of crystalline calcite 

as shown on plate 19, figure 2. Throughout the slide, 

calcispheres are seen in all stages of "dissolution." 
ROCKS OF THE MARTIN FORMATION 101 

Many lost their identity and are recognizable only as 

dim "ghosts" in the calcite. Most of these do not show 

up well in the illustration. 

Calcispheres of the spherical thick-walled type also 

occur in dolomites, both in the upper unit (pl. 8, fig. 3) 

and in the aphanitic dolomite unit (pl. 6, fig. 4). In 

these rocks they are everywhere dolomitized, and their 

detailed structure has been destroyed. 

Thick-walled calcispheres of type 2 have a hollow 

interior that is ellipsoidal rather than spherical; they 

occur also in limestones of both the aphanitic dolomite 

and the upper units of the Jerome Member. They are 

very abundant in some beds and are at places associated 

with thin-walled calcispheres, but they are less commonly associated with thick-walled calcispheres of type 

1. The type 2 calcispheres, furthermore, have more 

irregular outer surfaces (fig. 38). 

A typical rock in which the calcispheres are almost 

rock-forming is the calcitic dolomite illustrated on 

plate 20, figure 1. ~ieasurements of three wellpreserved calcispheres, marked on the plate, are as 

follows: 

a b c 

g h i j 

m 

TABLE 7.-Measurements, in microns, of calcispheres illustrated 

in plate 20, figure 1 

Specimen At __________________ _ B ___________________ _ c ___________________ _ 

Dimensions 

Outer 

370X250 

370X320 

300.X250 

Inner 

250X 190 

200X 150 

225X 190 

Thickness of shell 

20-55 

20-110 

15-45 

1 In specimen A and some others, traces of fibrous texture of the shell are preserved; 

in others, much recrystallization has occurred. 

The inside of each shell has a dark lining that is 

generally only a film, but in specimen B (pl. 20, fig. 1) 

and some others, it is as much as 18 microns thick. The 

outside of the she1ls is very irregular, as is better seen 

in dra1vings made from photographs (fig. 38, a-l). 

This irregularity seems to be an original feature of 

these shells and not one caused by diagenetic alterations. 

Somewhat more regular is another very large calcisphere from the same rock (pl. 15, fig. 5) that has outer 

dimensions of 640 X 480 microns, inner dimensions of 

400 X 275 microns, and a shell thickness of 25-100 

microns. The shell is entirely recrystallized. (See 

also fig. 38, f.) A peculiar radiate calcite body that 

0 

d e 

f 

k 

n 

FIGURE 3·8.-Sections of calcisp'beres. X 75. Radial lines, fibrous calcite; black, dark inner layer ; irregular lines, recrystallized calcite. ar-j, 

from calcitic dolomite in aphanitic dolomite unit of Jerome Member, section 6, Salt River Draw, subunit 10; g-k, from limestone, upper 

unit of Jerome Member, section 4, Salt River, subunit 18; l, from limestone, upper unit of Jerome Member, section 34, Tonto Natural Bridge, 

subunit 8; m, from limestone, Martin Limestone, Mount Martin, near Bisbee, Ariz.; n, from sandstone, upper unit of Jerome Member, section 27, Tonto and Horton Creeks, subunit 8. 
102 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

may be adventitious is lodged in the interior. It may, 

however, be organic because a calcisphere containing a 

rather similar radiate body was described from the 

Devonian of Silesia by Chapman (1924, pl. 8, fig. 6). 

The rock illustrated on plate 20 figure 1, also contains 

many thin-walled small calcispheres having diameters of about 100 microns; many of these may be 

detected by close scrutiny of the photograph. The rock 

is probably almost entirely organogenic. 

Many of the thin-walled small spheres are filled with 

calcite; many spheres of both kinds are engulfed by 

recrystallized calcite and are themselves partly 

recrystallized. 

Thick-walled calcispheres of type 2 also occur in finegrained partly recrystallized rocks of the Martin Limestone at the type locality-Mount Martin near Bisbee 

(pl. 15, fig. 3; pl. 16, fig. 3). Their wall structure has 

been completely altered. 

A somewhat similar, though more regular, type is 

represented by two well-preserved ca]cispheres found 

in fine-grained sandstones (pl. 9, fig. 6; pl. 15, fig. 6). 

One of these (pl. 15, fig. 6) has outside dimensions of 

about 500 X 400 microns, inside dimensions of 350 

X 300 microns, and a wall thickness of 40-85 microns. 

The wall in both specimens has a well-preserved fibrous 

texture; the characteristic dark zone is on the inside. 

The outside of the shells is smooth, and these forms are 

therefore transitional in their features to the genus 

V1nbella Maslov, to which they may belong. 

AFFINITIES 

As has been shown, "typical" calcispheres are of various morphological types, some of which are not necessarily closely related. However, all have been classified as calcispheres by observers in the past, although to 

my knowledge never have as many varieties been described from one stratigraphic formation as have been 

described from the Martin Formation. Classification 

and biologic affinities of these fossils are very much in 

doubt, and little progress can be made in their da.ssification as long as they are lumped together as they have 

been in the past or as long as only one or the other type 

is being considered by an author. 

Williamson (1881) believed that the calcispheres are 

some form of extinct Protozoa-though not Radiolaria. 

Cayeux (1929) regarded them as algae and believed 

that all calcispheres originally had perforate walls, 

although the wall st,ructure of many had been changed. 

Derville (1931) and Wanner (1940, p. 91) regarded 

them as Foraminifera; Kaisin ( 1926) believed that 

they are Protozoa-probably Foraminife,ra. Lombard 

and Monteyne ( 1952, p. 21) believed that they are most 

likely algal spores. Beales ( 1958) su o-o-ested that the,y • bb 

might be hystrichosphaerids, and Thomas (1932) and 

Pia ( 1937) thought that they were gas bubbles. Among 

those who simply admit that their systematic position 

is unknown are Deflandre (1949) Reitlinger (1957), 

and Konishi (1958). 

Thin-walled calcispheres seem to be very widespread 

geographically and stratigraphically, but they have 

rarely been well described or illustrated. Glover ( 1955, 

p. 6, fig. 9) described what appear to be thin-walled 

calcispheres from aphanitic limestone of Middle Devonian age in northwestern Australia as "minute recrystallized ooliths." The description of Cretaceous forms 

by Bonet (1956, p. 441), who named them Oalcisphaerula, is one of the best. These formS' are calcareous 

spheres that are 35-160 microns in diameter and have 

walls 5-10 microns thick. Bonet stated that they are 

widely distributed in Cretaceous rocks of Texas, Mexico, and Spain and the Alps, CarpathianS', and Caucasus. Their presence in the Georgetown Limestone 

of Late Cretaceous age of Texas had attracted attention 

before-for example, Thomas (1932) suggested they 

might be gas bubbles. This interpretation is, however, 

contradicted by the fact that the spheres of the Georgetown Limestone have very distinctly recognizable shells. 

Thomas called attention to the wide distribution of 

similar spheres and mentioned in particular the chalk 

of England, the Permian of Texas, Carboniferous limestones of England, and the Ordovician of Keisley and 

Westmoreland. Downie (1957, p. 429) mentioned similar spheres from the l(immeridge clay of England. 

Earlier, Rei's (1923, p.107) described identical spheres 

occurring in swarms in Tertiary fresh-water deposits 

of algal origin in the Palatinate of Germany. He 

named the objects Ohlorellopsis, because of their supposed affinities to the living green alga Ohlorella. Hacquaert ( 1932) called attention to this observation by 

Reis and reported similar objects in Devonian and Carboniferous rocks of Belgium. 

Bradley (1929, p. 207) ·recognized the presence of 

Ohlorellopsis in algal reefs in the Green River Formation (Colorado) of Eocene age. He convincingly 

pointed out that Ohlorellopsis Reis is related to the 

modern genus Ohlorocoacum rather than to Ohlorella. 

The habitat of Recent species of Ohlorococcum is either 

subaerial or fresh water. Ohlorellopsis is a fresh-water 

form, whereas almost all Paleozoic and Mesozoic forms 

discussed here are marine. No close biological affinities, therefore, are implied by these compa.risons. 

These observations apparently indicate that the study 

of calcispheres of the Oalcisphaera-Ohlorellop8is type 

has been much neglected, although the widespread occurrence of the calcispheres in rocks of all ages is apparent from the published record. 

The affinities of the thick-walled forms-the "fimbriata-type" as well as the more oblong types having 
ROCKS OF THE MARTIN FORMATION 103 

irregular surfaces-continue to remain enigmatic. The 

present study has made no substantial contribution to 

this problem. 

UMBELLA MASLOV (IN BYKOVA AND POLENOVA, 1955; NON 

D'ORBIGNY, 1841) 

Certain limestones and calcareous sandstones contain 

abundant remains of ovoid calcitic bodies that differ 

from typical calcispheres in size and shape and probably also in their mode of growth; they are therefore 

described separately (fig. 39, pl. 20; fig. 2, pl. 21). 

Typical specimens have an ovoid or ellipsoidal shape; 

they have a long diameter of as much as 450 microns 

and a short diameter of as much as 400 microns. 

Whereas many specimens have uniformly and smoothly 

rounded outlines, some especially larger ones tend to 

be flattened at one or both ends (pl. 20, fig. 2). The 

specimens consist of a shell composed of minute radially 

oriented calcite fibers; the shell encloses a hollow perfectly spherical space that is situated rather eccentrically within the ovoid. The shell, therefore, is thin on 

one end of the specimen and thick on the other; it 

ranges in thickness generally from 10 to 150 microns. 

The inner sphere is lined with a thin somewhat illdefined dark layer that is never more than 15 microns 

thick; the layer is commonly thi1mer and in some is 

present only as traces. 

In addition to the shells just described which constitute most of those present, the rocks contain many 

incomplete shells. The incomplete shells have an opening or aperture of varying width. Characteristically, 

the interior of all shells having such an opening is filled 

with limestone matrix, whereas the interior of almost 

all the complete shells is filled with crystalline calcite. 

Very few shells appear in thin section that are both complete and are filled with matrix; these shells undoubtedly have openings that were not cut by the section. The edges of the shell are smoothly rounded 

around the openings and show no evidence of breakage. 

I believe, therefore, that shells having openings represent immature stages of the species and that the shells 

became closed only during later growth stages (fig. 40). 

Additional support for this belief is the fact that in the 

largest specimens (more than 0.375 mm in diameter) 

the shell is entire and that most smaller specimens have 

open shells. Since both open and entire shells have 

identical structures, there is little likelihood that they 

represent different biologic forms. The sections shown 

in figure 39, therefore, probably illustrate ontogenetic 

stages of one species only. 

TABLE 8.- Measurements of sections of specimens of Umbella 

Maslov in sample T56- 521 

[Measurements in microns] 

Diameter Shell thickness 

Diameter Filling of 

Specimen of inner inner Remarks 

Long Short sphere Mini· Maxi· sphere mum mum 

- - -----

1. .. -------- 225 225 112 22 75 Calcite .. __ Shell entire. 2 ___________ 280 245 106 94 Matrix ____ Shell open. 3 ___ ___ _____ 280 262 115 65 _____ do ___ __ Do. 4 ________ ___ 300 280 245 65 ___ __ do __ ___ Do. 5 _____ __ ____ 300 280 253 56 ____ _ do _____ Do. 6 __ ______ ___ 300 262 188 28 94 Calcite ____ Shell entire. 7 __ _____ ____ 300 280 188 19 75 __ ___ do ..... Do. 8 ___________ 300 253 197 9 76 _____ do ___ __ Do. 9 ____ _______ 300 245 169 11 112 _ ____ do _____ Do. 10 __________ 320 300 225 112 Matrix ____ Shell open. 11 ____ ______ 328 280 188 19 112 Calcite ____ Shell entire. 12 __________ 338 320 ~-- -- --- -------- -------- ------------ Shell completely fibrous. 13 ___ ______ _ 338 253 168 28 131 Calcite ____ Shell entire. 14 ____ __ ____ 375 320 262 141 Matrix ____ Shell open. 15 __________ 385 320 106 56 131 Calcite __ __ Shell entire. 16 __________ 412 330 245 38 150 _____ do _____ Do. 17 __________ 450 3CO 202 75 112 .. ... do ..... Do. 18 __________ 450 395 290 38 112 __ ___ do __ ___ Do. 

FIGURE 39.-Speclmens of Umbella sp. X 88x. Radial lines, tibrous calcite; black, dark inner layer; irregular lines, coarsely crystalline calcite. 

Limestone, upper unit of Jerome Member, section 31, Wei:}ber Creek, subunit 31. 
104 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

FIGURE 40.-Reconstruction of suggested successive growth stages of 

Umbella, showing one half of shells sectioned longitudinully . . X 75. 

DISTRIRUTION 

In central Arizona the best-preserved specimens were 

found in aphttnitic limestone in section 31, Webber 

Creek, 317 feet above the base of the Jerome Member; 

they were more rarely found in section 8, Canyon Creek 

and possibly in the Martin Limestone at Mount Martin, 

near Bisbee, Ariz. 

I also recognized the species in aphanitic limestone in 

the Elbert Formation of Late Devonian age in Florida 

Valley, southwestern Colorado. Kon'ishi (1958, p. 103-

104) described a representative of probably the same 

species from the Cooking Lake Format ion in Alberta. 

He did not name it, but compared it with somewhat 

similar forms which Lombard and Monteyne ( 1952) described as "calcisphere de forme A." 

Outside North America forms which undoubtedly belong to the same genus were first described by Lombard 

and Monteyne (1952, p. 14--16). Their "calcisphere de 

forme A" occurs in the Frasnian of southern Belgium, 

where they are associated with trochilisks (probably 

Sycidium=Lombard and Monteyne's "calcisphere de 

forme C") and typical calcispheres. 

In 1955, Bykova and Polenova described the same organisms from rocks ranging in age from late Givetian to 

early Famennian, from many localities in the middle 

Devonian Field of the Russian platform, and from the 

Urals, Bashkiria, and elsewhere. They gave these 

forms the name Umbella, which was credited to Maslov 

in manuscript. The affinities of Umbella were sought 

with the foraminiferal family Lagenidae. Bykova and 

Polenova described a total of 10 named and 1 unnamed 

species. The species most similar to the Arizona form is 

Umbella baschkirica Bykova and Polenova (1955, p. 

38), which is late Givetian in age. 

Fossils that seem to belong to the same genus were 

illustrated as "Foraminifera with aragonitic shell" by 

Polonskaya (1956, pl. 6, fig. 40); they occurred in 

aphanitic limestone of early Famennian age in the Kuibyshev area. 

NOMENCLATURE 

The name U mbella was first used by d 'Orbigny ( 1841) 

for a molluscan genus (fide N eave, 1940, p. 609). If 

Umbella Maslov is a foraminifer, as Bykova and 

Polenova believe, the name would be preoccupied and 

the organism would have to be renamed. However, the 

affinities of Umbella Maslov seem to be far from certain, 

and if the genuG is an alga, the name would stand, because, as far as I am a ware, this name has not been previously given to a genus of plants. [After this manuscript was completed, Loeblich and Tappan (1961, p. 

284) proposed the name Umbellina to replace Umbella 

Maslov, and they accepted the genus as a foraminifer. 

However, they based their conception of the genus on 

the complete etched specimens of Umbella bella, figured 

by Bykova and Polenova, and the generic description of 

Umbellina is not easily applicable to the sections seen in 

thin sections illustrated by these and other authors, including those of the present report. Subsequently, the 

foraminiferal nature of Umbella ( Umbellina) in the 

sense of Loeblich and Tappan has been accepted by 

Ozonkowa (1962, p. 107) . On the other hand, Miklukho-Maklaj (1961, p. 655) treats Umbella Maslov as an 

alga ( Characeae?). It seems possible that the freely 

etched specimens described by Bykova and Polenova 

which served as types for Umbellina Loeblich and Tappan ( 1961) are not congeneric with the specimens shown 

as sections in aphanitic limestone by Bykova a.nd Polenova ( 1955) , Lombard and Monteyne ( 1952), Konishi 

(1958), and in this report. We may have to do here 

with two different kinds of organisms-one foraminifer 

( Umbellina Loeblich and Tappan) and one of uncertain 

affinities for which the name Umbella Maslov may be 

provisionally retained.] 

AFFINITIES 

The taxonomic position of Umbella Maslov cannot be 

decided on the base of available evidence. No organic 

remains that are very similar to it are known from 

either the animal or the plant kingdom or from among 

the Protista. (See Moore, 1954.) The closest resemblance is with certain calcispheres having a fibrous shell. 

These calcispheres, however, are a.lways much smaller, 

and their shell is spherical or irregularly spherical 

rather than ovoid or ellipsoidal as in Umbella Maslov. 

Lombard and Monteyne (1952) seemed to regard these 

organisms as algae or algal spores. Bykova and Polenova ( 1955) believed that the shells are cupshaped and 

are closed by a lid. (See especially their pls. 14 and 

15.) 

There is, however, no convincing evidence that any 

of the specimens shown in thin sections possessed such 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 105 

a lid (except in pl. 8, fig. 3, where a lid may possibly be 

adventitious) ; there is also no intrinsic evidence that 

the small capsules with lids figured by Bykova and 

Polenova are the same organisms as those shown in the 

thin sections. No other Foraminifera are known in 

which the aperture is closed by a lid. In fact, Bykova 

and Polenova rtferred to the brachiopod Richtho fenia 

and the pelecypod H ippurites as analogies to this structure. 

Bykova, Dain. and Fursenko (1959) established within the family Lagenidae the new subfamily Umbellinae 

for Umbella and two additional early Paleozoic genera, 

Oochleatina Bykova. and Illigata Bykova. The illustrations of Umbella given are only those of entire, apparently etched out shells, reproduced from Bykova and 

Polenova ( 1955). Since these bodies are not fully comparable with the limestone specimens studied in thin 

section, the systematic position of the limestone specimens continues to remain in doubt. 

The cup-shaped org~nisms having lids that Bykova 

and Polenova assign to Umbella are somewhat reminiscent of the Jurassic genus Schizophaerella Deflandre 

and Dangeard (1939), which, however, is only 12-30 

microns in size. The affinities of Schizosphaerella are 

likewise unknown. That these organisms are Foraminifera se~ms extremely doubtful, because as far as I 

am aware, lidlike structures closing the aperture are unknown in true Foraminifera. 

At present, Umbella Maslov is best regarded as an 

organism of uncertain taxonomic position that may 

represent either a new group of Protista or may ha.ve 

algal affinities. 

STRATIGRAPHIC SECTIONS OF THE MARTIN 

FORMATION 

EXPLANATION 

The figure and letter combinations at the end of each 

subunit description are sample numbers-for example, 

T56-282. 

The total thickness of the Martin Formation is the 

first figure for cumulative thickness given for the upper 

unit of the Jerome Member. 

Unless otherwise stated the Martin Formation is always overlain by Mississippian Redwall Limestone and 

underlain by undifferentiated Precambrian rocks. 

With the exception of many of the Thamnopora and 

all of the Amphipora, all identifications of corals and 

stromatoporoids are by W. A. Oliver, Jr. 

The identification numbers of the aerial photographs 

on which the locations of the measured sections appear 

are given for each section. The photographs are Army 

Map Service photographs, scale 1: 50,000. 

The locations of the measured sections are shown in 

plate 32. 

SECTION 1.-Sawmill Road 

[About 7% •miles by way of road east of U.S. Highway 60, on road 

through San Carlos Indian Reservation that branches eastward from 

U.S. Highway 60, 6 miles south of bridge over Salt River (San Carlos 

Indian Reservation, sec. 26, T. 4 N., R. 18 E., unsurveyed). Photograph lots AK 19•88, 1989. Measured by Curt Teichert, 19'53 and 

1956] 

Martin Formation: ~;:~- 1:;:~; 

Jerome Member : thick- thickUpper unit: <'}!~:) t/:~~) 

8. Hmestone, dolomitic, mottled Ught-brown 

(5YR 6/4) and pale-red (5R 6/2), very 

fine grained, argillaceous ; richly fossiliferous, containing crinoid ossicles, 

Thamnopora sp., Striatopora sp., Atrypa 

clarkei Warren, A. borealis Warren, and 

Gruenewaldtia americana Stainbrook; 

thin bedded to :flaggy; weathers light 

brown to pale brown. (TP-49, T56-282) _ 16 159 

7. Sandstone, light-brown, fine-grained, :flaggy; 

poorly exposed in part; becomes calcareous toward top_____________________ 18 143 

6. I .. imestone, light olive-gray ( 5Y 6/1), coarsegrained, medium-bedded ; contains some 

crinoid ossicles; weathers brownish gray_ 11 125 

5. Sandstone, grayish orange-pink ( 5Y R 7/2), 

very fine grained, well-sorted ; contains 

much calcareous matrix; abundant invertebrate tracks on bedding planes ; 

thick-bedded; weathers light brown_____ 13 114 

4. Limestone, biostromal, very light gray to 

light-gray ; consists entirely of stromatoporoids (Actinostroma? sp. and Stictostroma sp.) and of large colonies of 

Pachyphyllum. ( TP 48, T·56-283) _______ 18 101 

3. Sandstone, light-brown, coarse-grained ; contains quartz granules as much as 5 mm 

in diameter____________________________ 12 

2. Sandstone, light-brown (5YR 6/4), very 

fine grained, well-sorted, porous- probably due to leaching of calcareous cement; 

invertebrate tracks on bedding plains; 

thin- to medium-bedded, partly soft and 

poorly exposed; weathers light brown, with 

pitted surface. ( T206) ----------------- 20 

1. Limestone, mottled light-brown (5YR 6/4) 

and grayish orange-pink ( 5Y R 7 /2), very 

fine grained; upper part, medium grained; 

some calcispheres, abundant crinoid 

ossicles and some colonies of Au lop ora sp. 

in lower part of subunit ; crinoidal; contains chert bands consisting of irregularly 

fused :flat nodules 1-2 in. thick; medium 

bedded; weathers light brown. (T205) --- 51 

Fault contact at base of s-ection. 

83 

71 

51 
106 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 2.-Black River 

[About 1 'h miles south of junction of White and Black Rivers (Fort 

Apache Indian Reservation, SW% sec. 2, T. 4 N., R. 20 E., unsurveyed). Photograph lots AK 1992, 1993. Measured by Curt Teichert, 

1953, and by Teichert and R. L. Harbour, 1956) 

Martin Formation : 

Jerome Member : 

Upper unit: 

22. Siltstone, mostly covered; contains some 

marly limestone and shale ; very fosSttbunit 

thivkness 

(feet) 

OumuZative 

thickness 

(feet) 

siliferous__________________________ 35 271. 5 

21. Limestone, mottled light brownish-gray 

(5YR 6/1) and moderate red (5R 

5/4) ; medium- to coarse-crystalline; 

thoroughly mixed rock consisting of 

pellets, c a 1 cite crystals•, detrital 

quartz, and bioclastic material, including very small calcispheres and 

crinoid stems; quartz grains as much 

as 0.3 mm in diameter, mostly angular 

to subangular; subunit increasingly 

sandy toward top; medium bedded. 

(II56-7)-------------------------- 3 230.5 

20. Siltstone, yellowish-gray (5Y 7/2), calcareous; contains fossil fragments___ 3 233. 5 

19. Limestone, yellowish-gray ( 5Y 8/1), 

coarsely crystalline; friable on weathered surface; contains crinoid and 

brachiopod fragments ; scattered detrital quartz grains, subrounded, as 

much as 1 mm in diameter, all highly 

shattered; medium-bedded (beds 1 

ft. thick). ( II56-6) --------------- 6 230. 5 

18. Siltstone, calcareous, olive-gray ( Y5) ; 

fissile ; contains poorly preserved 

brachiopods; poorly exposed; slopeforming____________________________ 14 

17. Dolomitic limestone, very sandy, mottled light brownish-gray ( 5Y R 6/1) 

and pale-red (lOR 6/2) ; fragmental, 

mixed detrital carbonate and bioclastic material, brachiopod ( ?) and 

ostracode remains ; coarse-grained ; 

detrital q u a r t z grains present 

throughout unit, more abundant in 

certain layers and in top 6 in. ; individual quartz grains as much as 

0.5 mm in diameter, mostly angular, 

containing small admixture of subrounded g r a i n s ; medium-bedded. 

(II56-5)--------------------------- 1.5 

16. Dolomitic limestone, pale-red ( 5R 6!2), 

very fine-grained, argillaceous, thickbedded (beds 3 ft. thick) ; weathers 

pale red. (II56-4)_________________ 6 

15. Sandstone, pale reddish-brown (lOR 

5/4), coarse-grained; contains calcareous cement ; grains subrounded 

to subangular; friable; medium224.5 

210.5 

209 

bedded. (II56-3)___________________ 2 203 

14. Dolomite, pinkish-gray (5YR 8/1) to 

light brownish-gray (5YR 6/1) ; 

finely crystalline; contains dark calcite vugs as much as 2 em long; 

SECTION 2.-Black River-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

!14. Dolomite, etc.-Continued 

irregularly spaced laminae containing abundant quartz grains as much 

as 1.2 mm in diameter that are 

mostly subrounded to rounded, most 

grains having etched surface ; 

medium-bedded. ( II56--2) ----------

13. Dolomite, light olive-gray (5YR 6/1) ; 

very fine grained, crystalline ; individual crystals as much as about 0.1 

mm in diameter ; subconchoidal fracture; scattered small detrital quartz 

grains ranging from silt size to 1 mm 

in diameter; weathers light to dark 

gr·ay; medium-bedded. (II56-1) ---- 12. Shale, gray, poorly exposed __________ _ 

11. Dolomite, light brownish-gray (5YR 

6/1), fine-grained, very thick bedded 

to massive; cliff-forming; contains 

many calcite stringers; weathers 

light brown, with pitted surface. 

Subunit 

thickness 

(feet) 

5 

4 

1 

(T56-265) ------------------------ 10 

10. Dolomite, pale-red (5R 6/2) mottled 

with darker red, fine-grained, very 

sandy, thick-bedded to massive, cliffforming; lower half shows lamination on weathered surfaces, upper 

part has brecciated appearance; 

weathers light brown. (T56-263) --

9. Dolomite, pale-red ( 5R 6/2), and some 

purpllsh-red streaks, very fine 

grained, thin-bedded ( 4-6 in. beds 

thick) ; contains a few vugs as much 

as 1 em in diameter that are filled 

with brown calcite; in places, brecciation is indicated; wea;thers yellowish brown. (T56-263) -------------

8. Sandstone, pale-pink ( 5 RP 8/2), contains pale-red ( 5R 6/2) laminae; 

fine-grained, contains quartz grains 

about 0.1 mm in diameter ; thinly 

crossbedded; weathers light brown. 

(T56-262)-------------------------

7. Sandstone, light-gray (N7), coarsegrained contains subrounded quartz 

grains 0.3-1 mm in diameter ; soft, 

flaggy; weathers light brown to gray. 

8 

4 

12 

( T56-261) ------------------------- 10 

Aphanitic dolomite unit: 

6. Dolomite, grayish orange-pink (5YR 

7/2 to 5YR 8/2) to light olive-gray 

( 5Y R 6/1) , very fine grained, has 

subconchoidal fracture; scattered 

quartz grains mostly 0.1-0.2 mm in 

diameter, but some are as much as 

0.5 mm in diameter ; grains have 

varying degrees of roundness; in 

places grains occur in thin more 

densely packed layers; weathers 

light brown. (T56-260, 259, 258) -- 22 

Oumulative 

thickness 

(feet) 

201 

196 

192 

191 

181 

173 

169 

157 

147 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 107 

SECTION 2.-BZack River-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

5. Dolomite, very light gray (N 8) to palered (5 R 6/2) ; very fine grained and 

irregular fracture in lower part, 

aphanitic and conchoidal fracture in 

upper part; thick-bedded, bedding 

planes irregular; aphanitic-rock type 

contains very small quartz grains not 

larger than 0.1 mm and fragments of 

fine-grained dolomite 0.3-3 mm in 

diameter; weathers greyish orange 

to grayish orange pink. ( T56--256, 

Subunit 

thickness 

(feet) 

255) ------------------------------ 12 

4. Dolomite, has 3-inch brecciated hematitic zone at base; pale red (lOR 

6/2) in lower part, light brownish 

gray (5YR 6/1) in upper; aphanitic 

and conchoidal fracture in lower 

part; subaphanitic to very fine 

grained .and subconchoidal to very 

smooth fracture in upper part; generally thin bedded (beds 6--12, in. 

thick), but becomes more thick 

bedded in uppermost 8-10 ft; 

weathers to various Jhades of light 

gray and brown; at 3-4 ft zone of 

flat brown rind chert pebbles .as much 

as % in. thick and 1 in. long occurs ; 

at 15ft a zone of larger chert nodules 

as much as 2 ft long occurs; calcite 

veins and vugs present throughout 

entire subunit. ( T56--254, 253, 252, 

251, 250)-------------------------- 51 

3. Dolomite, pale-red (5R 6/2) to grayishred ( 5R 4/2) , medium-grained, very 

homogeneous ; has irregular fracture; medium bedded (beds 1-2 ft 

thick) , has irregular bedding planes ; 

weathers light olive gray; contains a 

few silicified brachiopods (possibly 

Atrypa) 7 ft above base. (T56--

249) ----------------------------- 10 

Fetid dolomite unit: 

2. Dolomite, light brownish- to light olivegray (5Y 6/1) to medium gray (N 5) 

in upper part; medium bedded (beds 

1-2 ft thick) ; laminated throughout, though less markedly in upper 

half, 5-6 laminae per inch ; very fine 

grained to almost aphanitic in 

upper part, where rock fracture is 

subconchoidal ; generally fetid odor, 

weaker in upper part; weathers 

various shades of light brown. 

(T56--248, 247, 246, 245) ------------ 34 

Cumulative 

thickness 

(feet) 

125 

113 

62 

52 

1SECTION 2.-BZack River-Continued 

Martin Formation-Continued SubBeckers Butte Member: t~f:t 1. Conglomerate grading into sandstone. At (j~!:) 

places where measured, this subunit can 

be subdivided as follows (T56--244) : 

C. Sandstone, medium-gray (N 5), 

medium- to coarse-grained; consists of tightly packed quartz 

grains 0.3-1.5 mm in diameter that 

are generally not well rounded 

(roundness 0.5-0.6) ; very little 

cement, s 1 i g h t 1 y calcareous; 

weathers brown. Thickness, 10ft. 

( T56--243.) 

B. Sandstone, light-gray (N 7) to 

brownish-gray ( 5Y R 4/1), has 

irregular brown mottling, mediumgrained ; poorly sorted, grains 

mostly 0.1-1 mm in diameter; generally medium- to well-rounded 

(0.5-0.7) ; s 1 i g h t 1 y calcareous 

cement; weathers brown. Thickness 1-2ft. (T56--242.) 

A. Conglomerate, greenish- to brownishgray ( 5Y R 4/1) ; poorly sorted, 

grains and pebbles range from 0.2 

mm to several centimeters in diameter; grains less than 1 mm in 

diameter are generally well 

rounded ; larger grains and pebbles 

generally c o n t a i n calcareous 

cement; pebbles mostly quartzite, 

but some larger feldspar fragments present; toward the top 2ft, 

this subunit changes into sandstone, which is medium to coarsegrained and poorly sorted and 

which is a mixture of poorly and 

well rounded grains; weathers 

gray to light brown. Thickness, 

6 ft. ( T56--241.) 

The entire member is cliff forming______ 18 

Precambrian: Troy Quartzite ( T56--240). 

SECTION 3.-Flying V Oanyon 

Cumulative 

thickness 

(feet) 

18 

[Near mouth of Flying V Canyon, on slope above intersection of U.S. 

Highway 60 and base of Jerome Member (Fort Apache Indian Reservation, SW%SW%, sec. 29, T. 5 N., R. 18 E., unsurveyed). Photograph lots AK 2010, 2011. Measured by R. L. Harbour, 1956] 

Martin Formation: Sub- OumuJ erome Member: t~7~t_ :~~~%~ 

Upper unit: <i:::) (j!!:) 35. Sandstone, light..Jbrown (5YR 6/4), medium fairly evenly grained; quartz grains 

subrounded ; calcareous cement ; thinbedded; weathers light brown. (H56--

60) -----------------------------------· 20 359 
108 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 3.-Flyimg V Canyon-Continued 

Martin Formation-Continued Sub- Oumu- unit lative 

Jerome Member-Continued thick- thickUpper unit-Continued <i!:~) <i~!~) 

34. Shale, dark-gray ; weathers greenish gray______________________________ 28 339 

33. Dolomite, light olive-gray (5Y 6/1), sandy 

to silty, finely crystalline; contains detrital quartz grains as much as 0.2 mm 

in diameter; medium~bedded ; scattered 

silicified brachiopod fragments ( Schizoplwria. sp.). (H 56-59)-------------- 30 311 

32. Sandstone, light olive-gray (5Y 6/1) to 

greenish-gray (5GY 6/1), irregularly 

laminated, fine-grained; quartz grains 

subrounded to subangular, embedded in 

finely crystalline dolomitic cement, which 

makes up as much as 50 percent of the 

rock; weathers pinkish gray. (H56-58) _ 6 281 

31. Siltstone alternating with shale; yellowishgray (Y 6) ; poorly exposed; slope-forming___________________________________ 20 275 

30. Dolomite, medium-gray (N 5) ; thinbedded; poorly exposed________________ 10 255 

29. Dolomite, light brownish-gray ( 5Y R 6/1), 

medium-grained; crops out in three beds 

separated by siltstone layers; mediumbedded; weathers light olive gray______ 4 245 

28. Dolomite, medium-gray ( N 5), finely cryst_alline, finely laminated; cliff-forming; 

thick-bedded ; weathers light olive gray. 

(H56-57, 56}-------------------------- 23 241 

27. Siltstone, poorly exposed_________________ 7 218 

26. Dolomite, medium light-gray ( N 6), medium-crystalline; crops out in two resistaut finely laminated beds; thick-bedded; 

weathers light olive gray. ( H56-55) ___ 5 211 

25. Siltstone, light olive-gray ( 5Y 6/1), fissile; 

contains numerous invertebrate trails on 

bedding planes. (56-54)-------------- 30 206 

24. Sandstone, medium-gray (N 5), very fine 

grained, dolomitic ; crops out in three 

'beds separated by sandy clay bands; 

thick-bedded___________________________ 7 176 

23. Siltstone, medium-gray (N 5]; slope-forming; poorly exposed____________________ 12 169 

Aphanitic dolomite unit: 

22. Dolomite, light-gray (N 7), fine-grained; 

detrital quar.tz grains at base, angular 

dolomite fragments at top______________ 1 157 

21. Dolomite, yellowish-gray ( 5Y 8/1), cliffforming, medium-bedded; contains thin 

layers of gray shale, very finely crystalline; abundant detrital quartz grains 

ranging from silt size to about 0.5 mm in 

diameter ; in uppermost foot, subrounded 

grains as much as 5 mm in diameter; 

weathers yellowish gray. (H56-53, 52)_ 13 156 

20. Dolomite, slightly calcitic, light-gray 

(N 7) ; microbreccia containing angular 

fragments of aphanitic dolomite as much 

as 1.5 mm in diameter embedded in very 

fine grained dolomite matrix ; thinbedded dolomite beds average 6 in. in 

SECTION 3.-Flyimg V Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

Sub- Oumuunit Zative 

thick- thick- ness ness (feet) (feet) 

20. Dolomite, etc.-Continued 

thickness and are separated by claystone 

layers as much as 3 in. thick; dolomite 

weathers yellowish gray. (H56-51) __ _ 11 

19. Covered ------------------------------- 14 

18. Dolomite, light-gray (N 7) to medium 

light-gray (N 6) ; finely laminated, medium crystalline; weathers light olive 

gray. (ll56-50)----------------------

17. Sandstone, brownish-gray (5YR 5'/1), 

quartzitic, fine- to medium-grained, crossbedded; base slightly channeled into 

underlying dolomite, contains fragments 

of dolomite and subangular granules of 

milky quartz ; forms resistant brown 

cap to underlying cliff-forming dolomite. 

2 

143 

132 

118 

(H56-49) ---------------------------- 2 116 

16. Dolomite, light-gray (N 7), very fine 

grained ; size of dolomite crystals generally less than 0.07 mm ; subconchoidal 

fracture ; cliff forming ; beds 2-3 ft thick ; 

weathers yellowish gray. (H56-48) ___ 9 114 

15. Covered -------------------------------- 4 105 

14. Dolomite, very light gray (N 8), aphanitic; conchoidal fracture; pelletal and 

clastic texture; contains small amount 

of crystalline cement; rich in detrital 

quartz grains ranging from silt size to 

0.5 mm in diameter ; grains partly highly 

etched; outcrops in two beds; thickbedded; weathers yellowish gray. (ll56-

47) ---------------------------------- 3 101 

13. Covered interval; siltstone fragments on 

slope -------------------------------- 2 98 

12. Dolomite, light-gray (N 7), aphanitic; one 

bed ---------------------------------- 3 96 

11. Shale and dolomite, poorly exposed______ 1 93 

10. Dolomite, light-gray (N 7), aphanitic; conchoidal fracture; very fine pelletal texture ; thick-bedded (beds are 4 ft thick) ; 

dark-gray chert in lenses and reticulating veins ; weathers brown; dolomite 

weathers yellowish gray. (H56-29, 28) _ 16 92 

9. Marl and shale, poorly exposed__________ 2 76 

8. Dolomite, light olive-gray (5Y 6/1), subaphanitic; subconchoidal fracture; extremely fine pelletal texture; scattered 

very small calcite vugs ; evenly bedded, 

individual beds about 2 ft thick separated by shale partings and scattered 

lenses of gray chert ; sea ttered quartz 

grains near base ; has some "ghosts" of 

calcispheres ; weathers yellowish gray. 

(H56-27, 26)-------------------------- 16 

7. Dolomite, medium-gray (N 6), subaphanitic; small irregular dark chert nodules 

having brown rinds; one poorly laminated bed is distinguished by an extensive system of coalescing lenses of 

mottled medium- and light-gray chert 

nodules as much as 1 ft thick__________ 4 

74 

58 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 109 

SECTION 8.-Flying V Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Sub- Oumuunit lative 

thick- thickness ness Aphanitic dolomite unit-Continued (feet) (feet) 

6. Dolomite, medium light-gray (N 6) to 

medium-gray (N 5), aphanitic; conchoidal fracture; very small calcite 

vugs; dark-gray chert pebbles having 

brown rinds ; thin bedded (beds are 6 

in. thick) ; upper part contains scattered detrital quartz grains, angular, 

as much as 1 mm in diameter; interbedded with scattered layers of gray 

shale; medium bedded; weathers yel- low gray. (II56-24) __________________ 10 54 

Fetid dolomite unit: 

5. Dolomite, medium light-gray (N 6) ; alternating very fine grained and aphanitic 

beds ; some dark chert nodules near base; 

medium-bedded (beds are 1 ft thick) ; 

weathers light gray. (II56-23, 22) ----- 12 44 

4. Dolomite, light brownish-gray (5YR 6/1) 

to light olive-gray (5Y 6/1) ; very finely 

and uniformly crystalline ; strong fetid 

odor; finely laminated; lamination 

caused by finely distributed organic matter; scattered shale partings and 

mottled white and dark-gray chert in 

small lenses; cliff-forming; thickbedded; weathers medium light gray. 

(II56-21) ---------------------------- 17 32 

Beckers Butte Member: 

3. Shale, dark- to medium-gray (N 5), dolomitic; interbedded with yellowish-gray 

argillaceous dolomite layers. Some of 

the shale beds contain abundant remains 

of a rich psilophyte flora (Teichert and 

Schopf, 1958). ( II56-20) -------------- 2 

2. Sandstone, light brownish-gray ( 5Y R 6/1) 

to light olive-gray ( 5Y 6/1), coarse 

grained, well-cemented, poorly sorted, 

containing many medium to fine grains; 

medium-bedded (beds about 1% ft 

thick) ; beds separated by thinner layers 

of green-tinted sandy shale; weathers 

grayish orange. (II56-18) ____________ 12 

1. C on g l o m e r a t e, dark yellowish-orange 

(10 YR 6/6) to dusky yellow (5Y 6/4), 

brecciated, poorly sorted; contains 

quartz grains ranging from silt size to 

coarse; contains weathered fragments 

of diabase ; iron stained ; friable ; contains calcareous cement; variable thickness averaging about__________________ 1 

Precambrian : Diabase sill. 

15 

13 

1 

SECTION 4.-Salt River Asbestos Mine 

[Above abandoned asbestos mine, on north bank of Salt River, about 

8 miles due east of road bridge of U.S. Highway 60 (Fort Apache 

Indian Reservation, NE~ sec. 30, T. 5 N., R. 19 E., unsurveyed). 

Photograph lots AK 2008, 2009. Measured by Curt Teichert and R. L. 

Harbour, 1956] 

Martin Formation: :::i~- ~~ft:; 

Jerome Member : thick- thickUpper unit: (;;;:) <i~:~) 

22. Covered with talus of Redwall Limestone; possibly underlain by green shale 15 280 

21. Shale, weathers grayish green; outcrops 

poor --------------------------------- 15 ~ 20. Dolomite, grayish-orange (10YR 7/4), finegrained, silty, medium-bedded to flaggy 

(beds as much as 18 in. thick), hard; 

at 7%-8% ft, olive-gray layers densely 

packed with nonsilicified Atrypa shells; 

weathers grayish orange. ( T56-312--

311) --------------------------------- 18 250 

19. Sandstone, light-brown (5YR 6/4) to 

grayish-orange (10YR 7/4), mediumgrained ; contains many larger grains as 

much as 1 mm in diameter; grains subangular to angular, clear; in places 

quartz grains densely packed, in places 

embedded in abundant calcareous cement; weathered specimens tend to be 

porous due to leaching of carbonate 

cement; thick bedded, massive, crossbedded; cliff-forming; weathers dark 

yellowish brown. (T56-310) ---------- 21 232 

18. Dolomite, grades into limestone; medium 

light-gray (N 6) to light-gray (N 7) ; 

thick-bedded (beds are 1-3 in. thick), 

hard, cliff-forming; subunit begins with 

fine-grained medium light-gray dolomite, 

which is overlain by medium light-gray 

to light-gray limestones that generally 

contain a scattering of idiomorphic dolomite crystals ; limestone is generally 

granular and contains abundant calcispheres; at 17 ft, a bed containing 

Amphipora occurs ; weathers generally 

yellowish brown. (T56-309, 308, 307) __ 27 211 

17. Sandstone, medium-gray; thick-bedded 

(beds are 1-3 in. thick) ; fine-grained, 

having a scattering of grains in the medium range, as much as 0.5 mm in diameter; much carbonate cement, which 

seems to consist of a slightly calcitic dolomite; crossbedded; cliff-forming; some 

beds are penetrated by vertical tubes 

lh-% in. wide, 2--3 in. long ; weathers 

light brown. ( T56-306) --------------- 11 184 

,16. Dolomite, medium-gray (N 5), very fine 

grained, hard; medium-bedded (beds are 

1 ft thick) ; weathers brownish gray. 

( T56-305) --------------------------- 2 173 
110 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CEN-TRAL ARIZONA 

SECTION 4.-SaZt River A.abeatoa Mine-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

15. Sandstone, yellowish-gray 

Sub- Oumuunit lative 

thick- thick- ness ness (feet) (feet) 

(5Y 8/1), 

coarse- to very coarse grained ; quartzose, having a very small amount of 

calcitic cement; quartz grains generally 

frosted, poorly sorted, ranging in size 

from 0.2 to 3.0 mm, mostly well rounded 

to subrounded; thin bedded (beds are 2-4 

in. thick) ; upper two-thirds of subunit 

generally finer grained, laminated and 

1slightly crossbedded ; uppermost foot is 

a gray silty sandstone; weathers grayish 

orange. (T56-304) ____________________ 16 171 

14. Dolomite, medium-gray (N 5) to medium 

dark-gray (N 4), very fine grained; subconchoidal fracture ; medium bedded 

(beds are about 18 in. thick) ; upper 

3 ft contains large (1 in.) calcite-lined 

vugs and scattered quartz grains as much 

'as 2 mm in diameter; cliff-forming; 

weathers yellowish brown. (T56-302) __ 10 155 

13. Dolomite, light olive-gray ( 5Y 6/1), finegrained ; tends to fracture along uneven 

surfaces, forming sharp angles ; contains 

scattered very small vugs filled with yellowish calcite; medium- to thick-bedded 

(beds are 1-3 ft thick) ; cliff-forming; 

at top of subunit, layer contains bra.-

chiopod fragments, probably stropheodontids; weathers orange gray. (T5'6-

301) --------------------------------- 5 145 

Q2. Dolomite, light-gray (N 7) to yellowishgray ( 5Y 8/1), fine-grained ; rough fracture surfaces ; silty to fine sandy ; thinlbedded (beds are 1-4 in. thick) ; 

weathers yellowish brown; at top of 

subunit, 2-in. layer of distinctly laminated gray chert. (T56-300) ---------- 5 140 

11. Dolomite, yellowish-gray ( 5Y 8/1) , subaphanitic ; subconchoidal fracture ; very 

thick bedded (beds are 1-5 ft thick) ; apparently at least partly laminated, although laminae visible only on some 

weathered surfaces; contains very few 

quartz grains; irregularly penetrated by 

vugs of various sizes, larger ones as 

much as 15 mm long, filled with clear or 

brown calcite; smaller vugs generally 

filled with brown calcite; weathers yellowish orange. (T56-299) ------------- 8 135 

Aphanitic dolomite unit: 

10. Dolomite, various shades of pink, red, and 

gray, varying from medium gray (N 5) 

to pale red ( 5R 6/2) , very fine grained 

to aphanitic; subconchoidal to conchoidal fracture; very pure carbonate; 

little or no porosity; thin-bedded (beds 

are 3-5 in. thick) ; weathers grayish 

orange. (T56-298-297) --------------- 21 127 

SECTION 4.-SaZt River A.abeatoa Mine-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Sub- Oumuunit lative 

thick- thickAphanitic dolomite unit-Continued (j;;:) <'}!!~) 

9. Sandstone, pinkish-gray ( 5Y R 8/1), medium-grained; contains quartz grains 

subrounded to subangular ; very small 

amount of slightly calcareous cement ; 

thick-bedded (beds as much as 3 ft 

thick) ; crossbedded, fores~t beds generally dipping south to southeast ; hard ; 

cliff-forming; weathers y e 11 ow ish 

orange. ('1.\56--296, 295) --------·------- 15 106 

8. Dolomite, medium light-gray (N 6), aphanitic ; conchoidal fracture ; uppermost 

bed fine grained, dense; thick-bedded; 

highly jointed; contains abundant 

chert nodules and chert impregnations; 

nodules as much as 4 in. long and 2 in. 

thick ; under microscope, showing 

"clouds" and interpenetra·tion texture ; 

uppermost bed has slight vuggy porosity. The rock here is very slightly calcitic; weathers light orange gray. 

(T56-294, 293) ------------------------ 22 

7. Dolomite, medium light-gray (N 6), very 

fine grained to aphanitic; subconchoidal 

fracture; medium-bedded (beds are 6-18 

in. thick)·; fine clastic appearance under 

the microscope ; lower 2 ft rich in angular to subangular quartz grains as 

much as 1.5 mm in diameter; chert pebbles abundant, partly on bedding planes, 

partly oriented in layers between bedding planes ; most are slightly larger 

than those in unit 6 and have irregular 

shape as much as 2% in. long and :JA, in. 

thick. The dense dolomite has calcite 

vugs and stringers oriented vertical to 

bedding planes; weathers yellowish 

gray. (T56-292, 291)----------------- 20 

6. Dolomite, medium-gray (N 5), aphanitic; 

conchoidal fracture ; thin-bedded (beds 

are 4-12 in. thick) ; finely laminated 

with many layers of brown-rind chert 

pebbles; generally %-1 inch long and 

%-:JA. inch thick; scattered calcite vugs; 

traversed by microscopic joints similar 

to those in rocks of subunit 4; weathers 

light olive gray. (T56-290) ----------- 8 

5. Dolomite, medium light-gray (N 6), finegrained, thick-bedded; some beds have 

a very vuggy porosity; vugs are elongated in general direction of bedding 

and as much as 10 mm long; weathers 

various shades of orange gray. The 

first five subunits are cliff .forming. 

(T56-289) ---------------------------- 4 

91 

69 

49 

41 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 111 

SECTION 4.-Sa.zt River Asbestos Mine-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Sub- Cumuunit lative 

thick- thickAphanitic dolomite unit-Continued tJ::~) (j:!h 

4. Dolomite, medium dark-gray (N 4), very 

fine grained ; subconchoidal fracture ; 

flaggy to thin bedded (beds are as much 

as 10 in. thick) ; contains scattered calcitic vugs and calcite veins; penetrated 

by microscopic joints (generally less 

than 0.1 mm thick), which are filled 

with slightly calcitic material; weathers 

light gray. ( T56-288) ---------------- 5 37 

Fetid dolomite unit: 

3. Dolomite, medium-gray (N 5) to light 

brownish-gray ( 5Y R 6/l), fine-grained, 

thin- to medium-bedded, (beds are 2 in. 

to 1% ft thick) although has a more 

massive appearance in outcrop; lamination visible on weathered surface, probably laminated throughout; generally 

similar to subunit 2, but without characteristic fetid odor; weathers yellowish brown. (T56-287) ---------------- 9 32 

2. Dolomite, medium-gray (N 5), finegrained; thin- to medium-bedded; very 

finely laminated, laminations 0.5-1 mm 

thick; slight fetid odor; weathers 

dark gray. At 8-9 ft intercalation of 

hard lighter gray very finely saccharoidal dolomite, containing calcitic matrix along the interfaces between dolomite grains; contains lumps of chert. 

(T56-286, 285) ------------------------ 15 23 

Beckers Butte Member: 

1. Sandstone, mottled light-gray (N 7) to 

brownish-gray (5YR 4/1) ; thick-bedded 

(beds are 1-3 ft thick) ; medium- to 

fine-grained ; generally quartzose, but 

contains a small amount of calcareous 

cement ; contain a few angular pebbles as much as % inch in diameter; 

crossbedded; cliff-forming; weathers in 

various hues of gray and orange. 

(T56-284) --------------------------- 8 8 

SECTION 5.-South of Salt River Bridge 

[East of U.S. Highway 60, about 1112 miles south of road bridge over 

Salt River (San Carlos Indian Reservation, 'SW~ sec. 36, T. 5 N., 

R. 17 E., unsurveyed). Photograph lots AK 1933, 1934. Measured 

by R. L. Harbour, 1956] 

Martin Formation : Subunit 

Jerome Member : thickFetid dolomite unit (top eroded) : (j;!:) 

8. Dolomite, light brownish-gray (5YR 

6/1), medium-crystalline, laminated; 

some laminae finely crystalline ; fetid 

ordor; contains white and yellowtinted chert in lenticular and irregular bodies; thin- to medium-bedded; 

weathers moderate brown. (H56-17)_ 3+ 

Beckers Butte Member : 

7. Covered, probably underlain by sandstone or shale______________________________ 5 

Cumulative 

thickness 

(feet) 

122+ 

SECTION 5.-South of Salt River Bridge-Continued 

Martin Formation-Continued 

Beckers Butte Member-Continued 

6. Conglomerate, grayish-orange (lOYR 7/4), 

pale-pink ( 5RP 8/2), and other colors ; 

partly silica-cemented; well-rounded 

granules of quartz and quartzite; contains pebbles as much as 1 in. in diameSubunit 

thickness 

(feet) 

ter ; lenticular beds of reddish sandy 

shale less than 6 in. thick ; very thick 

bedded (beds as much as 9 ft thick) ; 

cliff-.forming. (H56-16, 15) ------------ 61 

5. Sandstone, arkosic, grayish-red (lOR 4/2) ; 

generally fine grained; poorly sorted and 

contains large angular to subangular 

quartz grains as much as 2 mm in diameter ; also contains mica, feldspar, and 

dark minerals; interbedded with some 

silty layers; soft, niche-forming; weathers grayish-red. (H56-14) ------------- 5 

4. Conglomerate, grayish-red; contains thin 

beds of dark-red sandy clay; granules 

and pebbles are as much as 15 mm in 

diameter and compose about two~thirds 

of the rock____________________________ 10 

3. Siltstone and sandstone, grayish-red ; 

alternating in layers 6 in. thick; siltstone is fissile, argillaceous, and micaceous; sandstone beds crossbedded, becoming fine grained in upper part__________ 10 

2. Sandstone and conglomerate, pale-red ( 5R 

6/2) to pale red-purple (5RP 6/2) ; sandstone, very coarse grained, contains 

pebbles as much as 5 mm in diameter and 

much calcareous cement; conglomerate 

1beds, contain rounded cobbles as much as 

3 in. in diameter; thick-bedded (beds 

are 3 ft thick) ; crossbedded. ( H56-

13) ---------------------------------- 24 

1. Sandstone, arkosic, grayish-red ( 5R 4/2) ; 

coarse- to very coarse grained, poorly 

sorted ; contains some quartz grains as 

much as 2.5 mm in diameter; larger 

grains rounded to subrounded ; all grains 

coated with limonite; scattered pebbles 

as much as 25 mm in diameter. Rock is 

soft and poorly exposed; weathers grayish red. (H56-12)-------------------- 4 

Base covered. 

SECTION 6.-Salt River Draw (south section) 

Cumulative 

thickness 

(feet) 

114+ 

48+ 

38+ 

28+ 

[4 miles from junction of Salt River Draw and Salt River (SE~NE~ 

sec. 25, T. 6 N., R. 16 E., unsurveyed). Photograph lots AK 2067, 

2068. Measured by Curt Teichert, 1953] 

Martin Formation: 

Jerome Member : 

Sub-

'unit 

thickUpper unit: (j;!:) 

37. Covered, probably underlain by upper 

continuation of subunit 36_________ 11 

36. Shale, weathers yellowish gray-------- 4 

35. Covered, possibly overlain by lower conCumulative 

thickness 

(feet) 

480 

469 

tinuation of subunit 36 _____________ _ 6. 5 465 

34. Limestone, grayish-orange, very argillaceous; poor outcrops______________ 3 458.5 
112 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SEoTioN 6.-Salt River Draw (south seotion)-Continued 

Martin Formation-Continued Sub-

'rtnit 

.Jerome Membe-r-Continued thickUpper unit-Continued <i!!:) 

33. Covered ----------------------------- 25 

32. Limestone, streaky grayish-orange 

(10YR 7/4) and light-'brown (5YR 

6/4), very finely crystalline, very 

argillaceous ; sea ttered detrital quartz 

grains, as much as 1 percent, mostly 

fine; contains poorly preserved spiriferids; thin bedded; weathers light 

brown. (T145)____________________ 3 

31. Covered, probalbly underlain by limestone similar to subunit 28, but unfossiliferous (Tl44) ------------------- 23 

30. Chert, lenticular; contains poorly preserved spiriferids. (T143)__________ 1 

29. Covered ; slope strewn with rubble of 

argillaceous limestone______________ 13 

28. Limestone, dolomitic, mottled lightbrown (5YR 6/4) and pale yellowishbrown (10YR 6/2), very argillaceous, 

coarsely crystalline; contains large 

numb~rs of small dolomite rhombohedra; richly fossiliferous, containing 

crinoid stems, brachiopods (Atrypa 

clarkei Warren, Theodossia sp.), 

large poorly preserved gastropods; 

thin-bedded; weathers light brown. 

Cumulative 

thickness 

(feet) 

455.5 

430.5 

427.5 

404.5 

403.5 

(T142) --------------------------- 8.5 390.5 

27. Silicified rock, yellowish-gray ( 5Y 

8/1) ; consists of amorphous or cryptocrystalline groundmass of silica and 

contains abundant fine detrital 

quartz, and numerous dolomite rhombohedra, averaging 0.07 mm in diameter; small amounts of calcite, filling 

small irregular cavities; scattered 

small chert nodules, 4-5 mm in diameter; thin-bedded; weathers light 

olive gray. (T141) ---------------- 22. 5 382 

26. Sandstone, yellowish-gray ( 5Y 8/1) , 

coarse-grained, poorly sorted ; larger 

grains rounded to subrounded ; medium-bedded; some crossbedding; 

weathers light olive gray. (Tl40) __ 14. 5 359. 5 

25. Covered ; slope strewn with sandstone 

rubble ---------------------------- 17 345 

24. Sandstone, grayish-orange (10YR 7/4) ; 

generally medium-grained; poorly 

sorted, containing grains 0.3 mm in 

diameter and larger, generally subrounded; grains tightly packed and 

impressed on each other; little carbonate (calcitic dolomite) matrix; 

some of the more calcareous and less 

sandy layers contain crinoid stems 

and fragments of fish plates ( coccosteans?) ; thin-bedded ; abundant invertebrate tracks on bedding planes; 

weathers light brown; entire subunit 

poorly exposed. (T149)___________ 34 328 

[Subunits 20 to 36 form a prominent cli1f about 20ft. high] 

SECTION 6.-Salt River Draw (south section) -Continued 

Martin Formation-Continued 

.Jerome Member-Continued 

Upper unit-Continued 

23. Limestone, light-gray, very finely crystalline, unfossiliferous, thick-bedded_ 

22. Limestone, light olive-gray (5Y 6/1), 

Yery finely crystalline, pelletal ; contains Amphipora abundant small calcispheres as much as 0.3 mm diameter, and abundant corals ( Thamnopora? and other genera); medium 

bedded in lower 3 feet ; remainder 

thick-bedded (beds are 2% ft 

thick) ; weathers light brown. 

Sub-

'unit 

thickness 

(feet) 

6.5 

Oumulative 

thickness 

(feet) 

294 

(T137) --------------------------- 10.5 287.5 

21. Limestone, biostromal, light-gray ; 

composed of stromatoporoids. 

(T108) --------------------------- 1.5 277 

20. LimeSitone, light-gray ( N 7) , very finely 

·crystalline, pelletal ; contains Amphipora and small calcispheres as much 

las 0.15 mm in diameter; thick-bedded. 

.(T107) --------------------------- 12 

19. Dolomite, light olive-gray (5Y 6/1), 

finely crystalline, saccharoidal; contains vugs and stringers of white and 

brown calcite; thick-bedded; weathers 

1light brown. (T106) --------------- 10 

18. Limestone, dolomitic, light-gray (N 7), 

finely crystalline, contains large numbers of idiomorphic dolomite rhombohedra averaging 0.2 mm in size ; some 

ostracode tintinnids and abundant 

calcispheres 0.07-0.2 mm in diameter; massive; weathers light gray. (T105) ____________________________ 10 

117. Dolomite, slightly calcitic, yellowishgray ( 5Y 8/1) , very finely crystalline; 

saccharoidal; contains some interstitial calcite; calcite stringers and some 

irregular small chert nodules ; hard, 

massive; weathers yellowish gray. 

( T105, 103) ------------------------ 17 

16. Sandstone and siltstone, calcareous, 

streaky yellowish-gray ( 5Y 8/1) and 

pinkish-gray ( 5Y R 8/1) . In pla:ces 

there is so much calcareous and argillaceous rna trix that rock assumes 

character of calcareous fissile to platy 

mudstone; weathers yellowish gray. 

275.5 

263.5 

253.5 

243.5 

(T102) --------------------------- 17.5 226.5 

15. Sandstone, yellowiSih-gray ( 5Y 8/1), medium- to coarse-grained, poorly 

!SOrted ; most g~ains angular to subangular, a few grains are rounded; 

considerable overgrowth and contact 

etching of grains ; thin-bedded ; bedding planes contain invertebrate trails 

as much as 1 in. wide; weathers light 

brown. (T101) -------------------- U.S 209 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 113 

SECTION 6.-Salt River Draw (south section)-Continued 

Martin Formation-Continued Sub-

'll nit 

Jerome Member-Continued thickness Upper unit-Continued (feet) 

114. Sandstone, mottled grayish orange-pink 

(5YR 7/2) and pinkish-gray (5YR 

8/1), very fine grained; contains numerous rounded quartz grains 0.~.5 

mm in diameter; matrix, calcitic dolomite; thick-bedded; slightly laminated; weathers yellowish gray. 

Cumulative 

thickness 

(feet) 

(TlOO) ----------------------------- 2. 5 191 

Aphanitic dolomite unit : 

13. Dolomite, light-gray, aphanitic; con-

~choidal fracture; medium- to thickbedded (beds are 6-20 in. thick)____ 3. 5 188. 5 

12. Sandstone, light-gray (N 7), very fine 

grained, well-sorted; small amount o:f 

carbonate matrix (calcitic dolomite) ; 

platy; has invertebrate trails on bed-

,ding planes ; weathers light brown. 

(T99) ---------------------------- 4.5 185 

H. Dolomite, light-gray, aphanitic; con-

~hoidal fracture ; many calcite 

stringers___________________________ 2 

10. Dolomite, calcitic, medium-gray (N 5), 

very finely crystalline ; has pelletal or 

micro-arenitic structure; calcite occurs in small to microscopic vugs ; 

contains ostracode shells and shell 

fragments, and caleispheres of different types from 0.1-0. 7 mm in dia180.5 

meted. (T98)_____________________ 2 178.5 

9. Dolomite, very slightly calcitic ; yellowish-gray (5Y 8/1), aphanitic; conchoidal fracture ; sea ttering of detrital quartz grains as much as 1 mm 

in diameter ; larger grains subrounded ; shattered ; thin - bedded ; 

weathers yellowish gray. ( T97) _ _ _ _ 29 176. 5 

8. Dolomite breccia, light-gray___________ 2 147. 5 

7. Dolomite, very slightly calcitic, pinkishgray (5YR 8/1), aphanitic; conchoidal fracture; varying but generally 

small amounts of detrital quartz 

grains; scattered chert bands; thinbedded ; weathers pinkish g r a y . 

(T98)----------------------------- 50.5 145.5 

6. Dolomite, light brownish-gray (5YR 

6/1) ; aphanitic; conchoidal fracture; 

many small rounded chert nodules 

and some larger chert lenses; scattered detrital quartz of silt size ; 

upper part has irregular small calcite 

stringers; thin-bedded; weathers yellowish gray. (T95, 96) ------------ 24 95 

5. Dolomite, very slightly calcitic, light 

brownish-gray ( 5 r R 6/1), very finely 

crystalline ; elongated, rounded chert 

nodules as much as 1 in. long; thinbedded (beds are 4-6 in. thick) . (T92) _____________________________ 12.5 71 

SEcTION 6.-Salt River Draw (south section)-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Fetid dolomite unit : 

4. Dolomite, pale-red, finely crystalline; 

thinly laminated in part; continuous 

layer of gray chert lenses at top, 3 

in. thick; thin-bedded (beds are 4-6 

Sub-

'unit 

thickness 

(feet) 

in. thick)-------------------------- 16. 5 

Beckers Butte Member: 

3. Sandstone, pinkish-gray (5YR 8/1) to 

pale red-purple ( 5RP 6/2), very 

eoarsegrained, thick-bedded, crossbedded; weathers pale brown. (T91) _ 14 

2. Sandstone, conglomeratic; contains pebbles as much as 4 in. in diameter ; 

larger pebbles are quartzite, smaller 

ones are composed of quartz and 

chert; cliff-forming_________________ 2 

1. Sandstone, medium-gray (N 5) to grayish red-purple (5RP 4/2), very coarsegrained; has basal conglomerate of 

quartz pebbles as much as 15 mm in 

diameter ; poorly sorted subangul,ar 

to subrounded quartz grains having 

considerable overgrowth ; mediumbedded, some crossbedding. (T90) __ 26 

Precambrian: Dripping Spring Quartzite, light 

gray, cross-bedded, thin-bedded. 

SECTION 7.-Salt River Draw (north section) 

Cumulative 

thickness 

(feet) 

58.5 

42 

28 

26 

[East side of Salt River Draw, about 7 miles' upstream from its junc- tion with the Salt River (ll'ort Apache Indian Reservation, sec. 1, T. 6 N., R. 16 E., unsurveyed). Photograph lots AK 2067, 2068. 

Measured by Curt Teichert, 1953] 

Martin Formation : 

Jerome Member: 

Upper unit: 

5. Limestone, not studied in detail, gray, 

thick-bedded; contains TabellaephylSub-

'Unit 

thickness 

(feet) 

Z.um peculiaris. (T206) ------------ 32 

4. Limestone, light olive-gray, finely crystalline ; contains abundant detrital 

quartz grains as much as 2 mm in 

diameter, rounded to subrounded ; 

contains crinoid stems, Syringopora 

sp. (and Schizophoria sp. (TP205) ; 

thin- to medium-bedded____________ 38 

3. Dolomite, calcitic, light-brown (5YR 

6/4), very finely crystalline, saccharoidal, argillaceous ; rich in corals, 

abundant colonies of H emagonaria sp., 

Thamnopora sp., and Alveolites sp. 

(T203, T204)---------------------- 7 

2. Sandstone, calcareous, light - brown, 

well-sorted, very fine-grained; to finegrained ; layer containing Atrypa, at 

Cumulative 

thickness 

(feet) 

1401-

1081-

701-

14ft. (T203)--------------------- 33 631-

1. Limestone, biostromal, medium lightgray; consists of stromatoporoids and 

Thamnopm·a colonies ; layer containing Atrypa at top; very thick bedded_ 301- 301-

Lower part of section not exposed. 
114 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 8.-East side of Oanyon Oreek 

[Upper part of escarpment on eastern side of Canyon Creek, about 1

7 mile-s upstream from its junction with the Salt River (Fort 

,Apache Indian Reservation, east of center sec. 9, T. 6 N., R. 16 E., 

ummrveyed). Photograph lots AK 2066, 2067. Measured by Curt 

Teichert and R. L. Harbour, 1956i; additional observations by Teichert, 1957] 

Martin F·ormaHon : 

Jerome Member : 

Upper unit: 

29. Dolomitic limestone and dolomite, various shades of light gray and grayish 

pink, fine-grained to very fine 

grained, •probably thin bedded to 

flaggy throughout; some layers contain scattered small quartz grains ; 

weathers light brown ; very poorly 

exposed under rubble from overlying 

Red wall Limestone. ( T56-281, 280, 

279,278)--------------------------

28. Sandstone, light brownish-gray (5YR 

6/1), medium-grained; contains a 

few scattered coarser grains; quartz 

grains tightly packed, smaller grains 

subangular, larger grains subrounded ; some calcareous cement ; 

thin- to medium-bedded (beds are 2-

6 in. thick) ; weathers light brown; 

poorly exposed. ( T56-277) --------

27. Dolomite, medium-gray, finely crystalline, thin-~bedded (beds are 6--9 in. 

thick) ; contains traces of Thamnopora ----------------------------- 26. Dolomitic limestone, pinkish-gray; one 

massive bed of Theodossia coquina, 

containing an admixture of crinoid 

stems, compound and single rugose 

corals ( H emagonana occidens 

Stumm, Alveolites? sp.) in upper 6 

in. Position of about 80 percent of 

shells convex upward, except in 

uppermost layer, where positions 

vary. (T56-276) _________________ _ 

25. Limestone, magnesian, light brownishgray (5YR 6/1), coarse-grained, medi urn "'bedded (beds are 4-6 in. thick) , 

very homogeneous; weathers medium 

gray, with slightly pitted surface. 

(T56-275) ------------------------ 24. Dolomite, pinkish-gray (5YR 8/1) to 

pale-red ( 5R 6/2) , very fine grained ; 

finely and irregularly lamina ted, 

some layers contain small pebbles 

(2-10 mm) of light gray dolomite; 

thin bedded (beds are 3-4 in. 

thick) ; very poorly exposed ; 

weathers light 'brownish gray to light 

gray. ( T56-274, 273) --------------

Su.bunit 

thickness 

(feet) 

70 

6 

6 

Cumulative 

thickness 

(feet) 

516 

446 

440 

2.5 434 

5 431.5 

16.5 426.5 

SEOTION 8.-East side of Oanyon Greek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

23. Sandstone, grayish-orange (10YR 7/4), 

coarse-grained, thick-bedded (beds 

are 1-2 ft thick) , bedding irregular ; 

quartz grains tightly packed, subrounded to subangular. Penetrated 

by open tubes about 2 mm wide, 

many of which are perpendicular to 

'bedding plane ; others parallel or at 

various angles; cliff-forming; 

weathers yellowish brown, with 

pitted surface. (T56-272) ---------

22. Limestone, mostly biostromal : 

c. Poorly exposed, probably mediumbedded, gray, fine-grained ; 4-5 

ft. (T56-271.) 

b. Biostrome of stromatoporoids 

(Actinostroma sp. ) , H emagonaria sp., Pachyphyllum cf. 

P. woodmanni about (White), 

Alveolites sp., and favositoid 

colars; about 7 ft. (T56-

271.) 

Su.b-

'unit 

thickness 

(feet) 

15 

a. Limestone replete with Thamnopora sp. and brachiopods, 

chiefly Atrypa; 6 in__________ 12 

21. Sandstone, light-brown (5YR 6/4), 

coarse- to medium-grained; tightly 

packed quartz grains subrounded; 

medium bedded; weathers moderate 

brown. (T56-270)________________ a 

~0. Limestone, dolomitic, medium lightgray (N 6), very fine grained, thickbedded; very few vugs, filled with 

white calcite; stromatoporoid biostrome (Idiostroma't sp., Gerronostroma sp., and Pachyphyllum sp.), 

organic structures very largely destroyed through partial dolomitization; weathers medium light gray. 

(T57-443, T56-269) ---------------

i19. Dolomite, light-gray, very fine grained, 

thin-bedded; weathers light gray; 

lower 6 ft v:ery poorly exposed _____ _ 

18. Dolomite, light brownish-gray (5YR 

6/1) to grayish-pink, fine-grained, 

thick-bedded (beds are 8-10 in. 

thick); few large vugs, as much as 1 

em in diameter, filled with clear or 

pink calcite; weathers light brown. 

(T56-268) ------------------------

6 

8 

9 

Ou.mu.-

lative 

thickness 

(feet) 

410 

874 

266 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 115 

SECTION 8.-East side of Ganyon Greek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

17. Dolomite, grayish orange-pink (5YJl 

11/2), medium-grained, almost saccharoidal, hard, massive; little visible bedding. Considerable vuggy porosity, much of it in the form of tubular cavities about~ mm wide and 

oriented approximately vertical to 

'bedding planes ; possibly of organic 

origin ; lined with brown crystalline 

'Calcite. .Entire unit crossed by many 

closely spaced vertical joints along 

many of which slickensides are apparent; weathers medium light gray. 

(T56-267) -----------------------

16. Dolomite, grayish orange-pink (5YR 

7 /2), medium-grained, saccharoidal; 

partly calcite-filled vugs as much as 

l em in size irregularly sea ttered 

throughout rock; diff-forming; 

weathers light brown. (T56-266) __ 

1r5. Dolomite, pale-red (5R 6/2), finely 

\Crystalline, thick-bedded (beds are 3 

ft thick) ; cliff-forming; weathers 

~rayish red. (H56-46) ------------

14. Dolomite, pale-red (5R 6/2), finely 

crystalline, porous ; some pores filled 

with solid calcite crystals as much 

as 2 mm in diameter ; thin-bedded ; 

weathers pinkish gray. ( T57 -438) __ 

13. Sandstone, pinkish-gray ( 5Y R 8/1) , 

very fine grained, lamina ted ; tightly 

packed angular quartz grains, and 

a very small amount of calcareous 

matrix; thin-bedded, resistant; invertebrate trails; weathers yellowish 

gray. (T57-437) ------------------

12. Covered ---------------------------

11. Dolomite, light brownish-gray (5YR 

6/1), finely crystalline, laminated, 

porous; in part very sandy; contains 

detrital quartz grains ranging from 

silt size to 1 mm in diameter; 

larger g r a i n s subrounded and 

mostly highly etched on surface ; 

forming one resistant bed. (H56-

45) ------------------------------ 10. Siltstone, poorly exposed ___________ _ 

9. Dolomite, light brownish-gray (5YR 

6/1), very finely crystalline, slightly 

porous, medium- to thick-bedded 

(beds as much as 5 ft thick) ; weathers yellowish gray. ( H56-44) ____ _ 

8. Covered ----------------------------

Aphanitic dolomite unit: 

7. Dolomite, pinkish-gray ( 5Y R 8/1), 

very finely crystalline to subaphanitic; contains varying amounts of 

1745-100 0----64-6 

Sub-

•unit 

thickness 

(feet) 

11 

11 

12 

20 

s 

6 

2 

3 

11 

1 

Cumulative 

thickness 

(feet) 

357 

346 

335 

323 

303 

300 

294 

292 

289 

278 

SECTION 8.-East side of Ganyon Greek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

7. Dolomite, etc.-Continued 

detrital quartz grains ranging from 

silt size to about 2 mm in diameter, 

larger grains subrounded ; upper 

part contains angular fragments of 

preexisting dolomite; thick-bedded 

(beds are 3 ft thick) ; weathers 

Sub-

•unit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

yellowish gray. (H56-43, MP-96) __ 21 277 

6. Covered interval ; reddish-brown shale 

fragments on slope. ( H56-42) ____ 25 256 

5. Dolomite, only partly exposed unit, 

very light gray (N 8) to medium 

light-gray (N 6), aphanitic to very 

fine grained, thin- to mediumbedded ; small chert pebbles having 

brown rinds in basal part ; some beds 

have abundant detrital quartz, generally subangular grains with peripheral etching ; some beds contain 

detrital dolomite fragments, also 

small calcispheres and ostracodes ; 

other beds are finely laminated, and 

laminae showing evidence of microslumping. (H56-41-40, MP-105; 

H56-39,38,37,36)----------------- 70 231 

Fetid dolomite unit : 

4. Dolomite, light brownish-gray ( 5Y R 

6/1) , very finely crystalline to subaphanitic; finely laminated by finely 

distributed organic matter; emits 

strong fetid odor ; thin-bedded to 

medium-bedded; weathers light olive 

gray. (H56-35, 34)-------------- 15 161 

Beckers Butte Member: 

3. Sandstone, grayish- orange (lOYR 

7/4) to very pale orange (lOYR 

8/2), generally coarse grained, 

partly conglomeratic, poorly sorted, 

partly arkosic ; pebble beds, having 

individual pebbles as much as 20 mm 

in diameter and concentrated in 

pockets; outcrops in cliff-forming 

beds, which are as much as 20 ft 

thick and show large-scale oblique 

bedding having southward dips; 

weathers light brown. (H56-33, 32, 

T57-43, 46, 45, H56-31) ----------- 124 146 

2. Conglomerate, sandstone, and siltstone, poorly exposed, crossbedded. 

(T57-434) ----------------------- 6-21 22 

1. Sandstone, grayish orange-pink (lOR 

8/2), poorly sorted, very coarse 

grained to coarse-grained ; contains 

pebbles as much as 7 mm in diameter; weathers a dark shade of grayish orange pink. (H56-30) -------- 0-1 1 

Precambrian: Mazatzal Quartzite: Quartzite, light-gray, finegrained, finely crosslamina ted. ( T57 -433.) 
116 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 9.-0ak Creek Farm Road 

[Road from Grasshopper to Oak Creek Farm, 3 miles southwest of 

Grasshopper, Navajo County (Fort Apache Indian Reservation, east of center sec. 32, T. 8 N., R. 16 E., unsurveyed). Photograph lots 

AK 2134. Measured by Curt Teichert, 1953; additional observations by Teichert, 1956] 

Martin Formation : 

Jerome Member : 

Upper unit: 

26. Limestone, medium-gray (N 5), subaphanitic; scattering of detl"ital 

quartz, in places concentrated in 

small lenses ; grains ranging from 

0.1 to 0.5 mm in diameter, all badly 

shattered; weathers medium light 

Sub-

•unit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

gray. (T198)____________________ 3 142 

25. Chert and silicified limestone, lightgray to light brownish-gray ; 

highly fossiliferous, ·containing 

spiriferids and large fauna of rugose corals, including Hexagonm·ia occi.dens Stumm; weathers 

into large angular blocks ; corals 

weathering out singly. ( T197) ___ 6 139 

24. Sandstone, grayish orange-pink ( 5Y R 

7/2), very fine grained to silty, wellsorted, thin - bedded, laminated ; 

weathers grayish brown. (T196) __ 16 133 

23. Chert and silicified limestone, lightgray (N 7) to light brownishgray (5YR 6/1); highly fossiliferous ; contains specimens mostly 

of Atrypa. (T195) -------------- 1 117 

22. Covered --------------------------- 5 116 

21. Limestone, pale-red, medium-crystalline; contains Atrypa fragments; 

weathers in rounded outcrops______ 4 

20. Limestone, very light gray, very fine 

grained ; contains fragments of 

Atrypa, Sp·inatrypa, and spiriferids; thin-bedded; weathers into angular plates. (T194) ------------- 11 

19. Sandstone, pinkish-gray (5YR 8/1), 

very poorly sorted ; smaller grains 

subangular, larger grains (as much 

as 2.5 mm) subangular to subrounded; much calcitic, sparry 

cement, constituting locally more 

than 50 percent of rock; most larger 

quartz grains have peripheral etching ; contains poor brachiopod 

fragments; crossbedded; disintegrates easily on weathering. 

111 

107 

( T193) ------------------------- 4 96 

18. Limestone, mottled gray; has abundant stromatoporoids (Actinostt·oma, Anostylostroma, Stictostroma); massive; weathers medium gray. ( T191) ---------------- 2 92 

17. Sandstone, very pale orange (lOYR 

8/2) ; medium-grained laminae; 

calcareous matrix; thin-bedded; 

weathers grayish orange pink. 

(T192) ---------------------------- 4.25 89.75 

SECTION 9.-0ak Creek Fa.rm Road-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

16. Sandstone, calcareous, pinkish-gray; 

contains some poor gastropod remains --------------------------

15. Covered, possibly underlain by platy 

pale-red sandy limestone _________ _ 

14. Dolomite, calcitic, pale-red (5R 

6/2) , very fine grained ; contains 

abundant large calcite vugs and 

much interstituial calcite; poorly 

preserved impressions of gastropods 

(Ar-izonella?) as much as 2 em in 

diameter; medium-bedded; weathers pale red. (T190) ___________ _ 

13. Sandstone, pinkish-gray (5YR 8/1), 

coarse-grained, poorly sorted ; contains subrounded grains as much 

as 4 mm in diameter, also contains scattered limestone pebbles 

as much as 4 em in diameter; 

much calcareous matrix; very fossiliferous, containing ?Fat1osites 

sp., Oyrtospi·rifer cf. 0. whitney 

Hall and unidentified brachipods; 

thick- bedded; weathers light 

brovvn. (Tl88) _________________ _ 

12. Limestone, mottled yellowish-gray 

( 5Y 8/1) and very light gray ( N 8), 

very fine grained to aphanitic; 

contains Amphipora, Styliolma ( ? ) , 

abundant ostracode fragments 

ruud calcispheres, as in subunits 

8 and 10; near top, one bed contains abundant specimens of Tham-

;nopMa sp. and some stromatoporoids; medium-bedded bed (A-6 

in: thick) ; weathers grayish 

Sub-

'Unit 

thickness 

(feet) 

4 

4 

5 

4 

orang~ (T187) _________________ 17 

11. Limestone, light-gray; aphanitic; conchoidal fracture; contains some unCumulative 

thickness 

(feet) 

85.50 

81.50 

77.50 

72.50 

68.50 

identifiable gastropods near top; 

thick-bedded------------·--------- 4. 50 51. 75 

10. Limestone, light brownish-gray (5YR 

6/1); some pale-red (5R 6/2) beds 

near base ; very fine grained to 

aphanitic ; conchoidal and subconchoidal fracture ; pelletal structure; lower pale-red beds penetrated by many vermicular calcite 

vugs ; some ostracode fragments 

and abundant calcispheres, 0.1-0.2 

mm in diameter ; some poor gastropod fragments weathered out on 

slope; meditun-bedded ; weathers 

light brown. (Tl85, 186) -------- 6. 75 47.25 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 117 

SECTION 9.-0ak Creek Farrm Road-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

9. Limestone, mottled light brownishgray (5YR 6/1) and grayish~red 

(5R 4/2); subaphanitic; subconchoidal fracture; pelletal or finely 

clastic structure; scattered detrital 

quartz : subangular grains as much 

as 0.5 mm in diameter ; mediumSub-

'ltnit 

thickness 

(feet) 

Ounttllative 

thickness 

(feet) 

bedded; weathers light gray. 

(T184)___________________________ 8.50 40.50 

8. Limestone, light brownish-gray ( 5Y R 

6/1), very finely crystalline to aphanitic; pelletal structure; abundant 

calcispheres, 0.1-0.2 mm in diameter ; bryozoan fragments; thinbedded; weathers medium light 

gray. (T183) -------------------- 5. 50 32 

7. Mostly covered; very poor outcrops of 

fine-grained crossbedded lightbrown sandstone_________________ 1

11 26. 50 

6. Sandstone, yellowish-gray (51' 8/1) 

with pale-red spots, hard, quartzitic, medium-grained; contains a 

few grains as large as 1 mm ; grains 

generally rounded to subrounded ; 

almost all grains have considerable 

overgrowth ; weathers medium light 

gray. (~,182)-------------------- 4.50 15.50 

5. Covered, probably urnderlain by brown 

platy sandstone__________________ 3 11 

4. Limestone; like subunit 2___________ 1 8 

3. Sandstone; like subunit L-----~--- 2 7 

2. Limestone, medium light-gray and 

pal~red mottling, very fine grained 

to aphanitic; penetrated by numerous more or less vertical calcitic 

tubes, 2 mm wide and 100 mm or 

more long, which are probably burro\vs ---------------------------- 2 5 

1. Sandstone, mottled pinkish-gray ( 5Y R 

8/1) and grayish-red (5R 4/2), fineto medium-grained ; some larger 

rounded grains are as much as 1 

mm :iln diameter; smaller grains 

tightly packed, angular to subangular; weather pale brown. ( T180) _ 3 3 

Precambrian : Mazatzal, Quartzite, mottled 

light-gray and pale-red. 

SECTION 10.-Spring Canyon 

[0.5 mile east of junction ()f Spring and Canyon Creeks at Chediski, 

Navajo County (Fort Apache Indian Reservation, SWJANWJA sec. 

36, T. 9 N., R. 15lh E., unsurveyed). Photograph lots AK 3255, 

3256. Measured by Curt Teichert, 1953] 

Martin Formation : 

Jerome Member: 

Upper unit: 

4. Dolomite, pal~ red ( 5R 6/2), finely 

crystalline ; irregularly distributed, 

poorly sorted detrital quartz (as 

much as 15 percent of rock) rangSub- Oumu-

•unit lative 

thick- thick- ness ness (feet) (feet) 

SECTION 10.-Spring Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

lTpper unit-Continued 

4. Dolomite, etc.-Continued 

ing .from silt size to grains as much 

as 1 mm in diameter; larger grains 

rounded to subrounded ; weathers 

Subunit 

thickness 

(feet) 

Oumulative 

thickness 

(feet) 

grayish orange pink. ( T158, 157) _ _ 12 36 

3. Sandstone, grayish orange-pink (lOR 

8/2), fine-grained, well-sorted; 

maximum of 20 percent calcareous 

matrix; grains as small as 0.1 mm 

in diameter subrounded ; channeling into surface of biostromal limestone, subunit 2; friable. (Tl56) __ 8. 5--16 24 

2. Limestone, biostromal, very light 

gray ( N 8) ; consisting predominantly of stromatoporoids (Gerronostt·orna., I diostr·oma) and favositids and admixture of rugose 

corals (Thamnopora, A.lveolites, 

Disphyllmn ?, Tabulophyllum). 

( T155) --------------------------- 0-7. 5 8-15. 5 

1. Limestone, very light gray (N 8), 

very finely crystalline ; upper 2 ft 

richly fossiliferous, containing 

Tlwmnopora. sp. and Atrypa. cf. A. 

clarke& ·warren; thick-bedded; 

weathers light gray. ( T154) ----- 8 8 

Precambrian: Mazatzal Quartzite, platy, cross~ 

bedded. 

SECTION ll.-Sprtng Canyon 

[About 1 mile southeast of junction of Spring and Canyon Creeks near 

Chediski, Navajo County (Fort Apache Indian Reservation, SEJA 

SWJA sec. 36, T. 9 N., R. 15lh E., unsurveyed). Photograph lots 

AK 3255, 3256. Measured by Curt Teichert, 1953] 

Martin Formation : 

Jerome Member : 

Upper unit: 

18. Chert and silicified limestone, lightgray ; rich in calcispheres, crinoid 

stems, and specimens of Spinatrypa 

sp. and Schizophoria sp., at least in 

basal part ; weathers brownish gray ; 

Sub-

•unit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

poorly exposed. (T178, 177)______ 8 75 

17. Sandstone, mottled pale-red and pinkish-gray, poorly sorted, fine- to medium-grained, grains rounded to subrounded; very crossbedded; thickbedded; cliff-forming. ( T176) ---- 16 67 

16. Limestone, ,biostromal, light-gray ; 

consists mostly of stromatoporoids 

and accessory fa vositids and 

Thamnopora; base of subunit undulating, having relief of about 3 ft; 

top irregular, having relief of about 

1 ft ; uppermos-t 6-12 in. contains 

limestone boulders as much as 10 in. 

in diameter ; evidence of penecontemporaneous weathering at top of 

subunit; massive; avel'age thickness------------------------------ 6 51 
118 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SEOTION 11.-Spring Canyon-Continued 

Martin Formation-Continued Sub-

•unit 

Cumulative 

Jerome Member-Continued 

Upper unit-Continued 

15. Limestone, light-gray, aphanitic to very 

finely crystalline ; pockets of Thamnopora colonies near base; thickbedded. ( T175) -------------------

14. Limestone, dolomitic, pinkish-gray. 

finely crystalline, saccharoidal ; 

medium-bedded, laminated. (T175) _ 

13. Covered-----------··-----------------

12. Limestone, light brownish-gray (5YR 

6/1), finely crystalline; pelletal matrix containing calcispheres; considerable amount of detrital quartz, subrounded to rounded grains as much 

as 0.7 mm in diameter; thin-platy, 

laminated; weathers medium light 

gray. (T173) ____________________ _ 

11. Covered-----------------------------

10. Limestone, light-gray (N 7), apha.-

nitic ; irregular fracture ; large 

amounts of scattered detrital quartz 

grains, subrounded to rounded, as 

much as 0.7 mm in diameter; medium-bedded (beds are 8-10 in. 

.thick) ; weathers light brownish 

gray. ( T172) -------------------- 9. c·overed ____________________________ _ 

8. Limestone, light-gray, platy----------

1:. Covered-----------------------------

6. Limestone, light brownish-gray ( 5YR 

6/2), aphanitic; conchoidal fracture; 

contains calcispheres and crinoid 

fragments; contains scattered detrital quartz in rounded to subrounded 

grains as much as 0.4 mm in diameter; weathers medium gray. 

(T171)----------------------------

5. Sandstone, mottled pink'ish-gray ( 5YR 

8/1) and grayish-red (5R 4/2), 

medium-grained; has calcareous 

matrix and calcite vugs; grains 

rounded; thin-bedded (beds are 4-10 

in. thick), laminated; weathers motthick- thick- ness ness (feet) (feet) 

3 45 

3.5 42 

2.75 38.5 

. 5 35.75 

2 35.25 

5.75 33.25 

2.75 27.5 

. 5 24.75 

5 24.25 

1 19.25 

tled reddish-gray and gray. (T170) _ 10 18. 20 

4. Sandstone, finely mottled pinkish-gray 

(5YR 8/1) and pale-red (5YR 6/2), 

fine-grained, well-sorted; contains 

much calcareous matrix, which in 

lower part is recrystallized in large 

units having uniform crystalline 

orientation ("Fontainebleau structure") ; weathers pale brown. 

( T167) --------------------------- 5. 5 8. 25 

3. Limestone, light-gray (N 7), finegrained, pelletal ; contains brachiopod and crinoid fragments and calcispheres; weathers medium light 

gray. ( Tl66) --------------------- . 5 2 .. 75 

SECTION 11.-Spritng Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

2. Sandstone, mottled pale-brown ( 5.YR 

5/2) and grnyish orange-pink (lOR 

8/2), medium-grained, well-sorted; 

grains rounded to subrounded ; some 

calcareous matrix; laminated. 

Sub-

'Unit 

thickness 

(feet) 

(Tl65)~--------------------------- .75 

1. Sandstone, pale-red (5R 6/2 to lOR 

6/2), some pinkish-gray patches, 

fine-grained, well-sorted ; grains subrounded; calcareous matrix ; at base, 

pebbles and boulders of underlying 

quartzite are as much as 2ft in diameter; thin-bedded; weathers pale 

Cumulative 

thickness 

(feet) 

2.20 

red. (T164)______________________ 1.5 1.5 

Precambrian : Mazatzal Quartzite. 

SECTION 12.-Lost Tank Canyon 

[North side of Lost Tank Canyon, 1-2¥.! miles upstream from junction 

of Lost Tank Canyon and Canyon Creek (Fort Apache Indian Reservation; section lies somewhat obliquely through central parts of 

sees. 1 and 2 T. 9 N., R. 15 E.). Photograph lots· AK 3256, 3257. 

Measured by Curt Teichert and R. L. Harbour, 195·6] 

Martin Formation: Sub-

'unit Jerome Member : thickUpper unit: (j;;:) 

46. Sandstone, pale reddish-brown (lOR 

5/4), fine- to medium-grained; contains detrital subangular to subrounded quartz grains; color due to 

limonitic staining; very porous, porosity ranging from about 5 to 10 percent; porosity may be due to leaching of original calcareous cement; 

poorly exposed. ( T56-389, TP56-

403) --------------------·----------- 2 

45. Dolomite, calcitic (or dolomitic limestone), pale-red (5R 6/2); very fine 

grained to aphanitic; contains a few 

silt-sized particles of detrital quartz 

(these, however, are poss.ibly silicified fossil fragments) ; microstylolitic, 

stylolitic sutures spaced as closely as 

1 mm, some stylolitic sutures visible 

with naked eye; lower part contains 

silicified At'rypa shells and shell fragments; 6-in. brachiopod coquina occurs at 8 fit; part above the coquina 

is almost unfossiliferous ; thin bedded 

to :tlaggy ; weathers light brown. 

(TP56-402, 388) ------------------- 20 

44. Dolomite, calcitic (or dolomitic limestone), pale-red (5R 6/2), very fine 

grained; contains large number of 

silicified specimens of Theodossia, 

in places acquires aspect of a brachiopod coquina; thick-bedded (beds are 

1-2 in. thick) ; weathers pale red. 

(TP56-387)------------------------ 3 

Cumulative 

thickness 

(feet) 

386 

384 

364 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 

SECTION 12.-Lost Tank Oanyo~Continued 

Martin Formation-Continued ~~fi 

Jerome Member-Continued 

Upper unit-Continued 

43. Dolomitic limestone, pale-red (5R G/2), 

very fine grained ; contains very scattered silt-sized detrital quartz particles and scattered small cavitie<s, as 

much as 2.5 mm in diameter, filled 

thickness 

(feet) 

with calcite; scattered crinoid ossicles ; thin-bedded to flaggy ; weathers light brown. (TP56-386) ----- 8 

42. Dolomite, calcitic, grayish-red (5R 4/2) 

fine- to medium-grained; contains 

very few detrital quartz grain<s, as 

much as 1.2 mm in size; scattered 

cavities, 0.5-0.7 mm in diameter, 

filled with calcite; in places, lamination brought out by weathering; 

thick-bedded; weathers olive gray. 

(TP56-385) ----------------------·- 4 

41. Dolomite, silty (or dolomitic siltstone?), pale-red (5R 6/2) ; matrix 

is a dense slightly calcitic dolomite, 

which is mixed in about equal portion 

with siltsized quartz particles, mostly 

about 0.06 mm in diameter; laminations result from tighter packing of 

silt in thin layers, which are 3-6 mm 

apart; thin-bedded to flaggy; weathers pale red. (TP56-401, 384) ------ 4 

40. Sandstone, pale-red ( 5R 6/2), fine- to 

medium-grained; consists of tightly 

interlocking mosaic of quartz grains 

that are generally subangular to subrounded and very little deformed; 

thick-bedded (beds are lh-3 in. 

thick) . distinctly laminated and very 

highly crossbedded ; weathers reddish 

brown. (TP56-383) --------------- 6 

39. Sandstor;e, pale-red (lOR 6/2), very 

fine grained, most grains about silt 

size ( 0.06mm) ; contains large 

amount of carbonate cement, which 

seems; to be a calcitic dolomite; thinbedded to flaggy ; weathers grayish 

red. (TP56-382) ------------------ 10 

38. Sandstone, white (N 9) to pinkish-gray 

(5YR 8/1), medium-grained; consists 

of rather tightly interlocking mosaic 

of detrital quartz grains, many of 

which are somewhat deformed, and 

small quantity of calcareous cement; 

roundness varies from subangular to 

well rounded, although original shape 

is deformed in many places; thickbedded (beds are lh-3 in. thick) ; 

massive; ledge-forming; weathers 

medium gray. (TP56-400) --------- 7 

37. Limestone, light olive-gray (5YR 6/1), 

dense ; subconchoidal fracture ; brecciated and in part biostromal, containing stromatoporoid colonies ; 

thick-bedded; weathers gray to 

brown. (TP56-399) ---------------- 5 

Cumulative 

thickness 

(feet) 

361 

353 

349 

345 

339 

329 

322 

SECTION 12.-Lost Tank Oanyo~Continued 

Martin Formation-Continued ~:fi 

Jerome Member-Continued t!~~~-

Upper unit-Continued (feet) 

36. Limestone, light brownish-gray (5YR 

6/1) ; fine-grained; calcarenitic, consisting principally of more or less 

rounded limestone grains as much as 

1 mm in diameter; matrix between 

these grains mostly recrystallized, giving rock a finely vuggy appearance; 

thick-bedded; weathers yellowish 

gray. (TP56-398) ----------------- 1 

35. Dolomitic limestone, light brownishgray (5YR 6/1), sandy; limestone matrix aphanitic, apparently originally 

calcarenitic ; contains many idiomorphic dolomite crystals, which possibly 

make up as much as 20-25 percent of 

the rock; irregularly scattered quartz 

grains, mostly very fine to fine, and 

scattered grains as much as 0.75 mm 

in diameter ; grains more than 0.3 mm 

in diameter are well rounded, those 

less than 0.3 mm are mostly angular; thick-~bedded (beds are 10 in. to 

2 ft thick) ; subconchoidal fracture ; 

weathers light olive gray. (TP56-

397)------------------------------- 4 

34. Limestone, biostromal, yellowish-gray 

( 5Y 8/1) ; lower part brecciated, somewhat laminated, contains many stromatoporoid fragments ( Gerronostroma sp., I diostroma sp.) and scattered 

Favosites colonies; upper 3 ft contains dense packing of large spherical 

stromatoporoid colonies as much as 2 

ft in diameter; thick-bedded, massive. 

( TP-56, 396, 395) ------------------ 7 

33. Dolomite, pale-red, very fine grained; 

rich in recrystallized Thamnopora 

skeletons, particularly in uppermost 6 

in. ; thick-bedded; very similar in appearance to subunit 3L_____________ 2 

32. Dolomite, grayish.:pink ( 5R 8/2), slightly calcitic, very fine grained; contains 

scattered, poorly recrystallized Thamnopora skeletons ; thick..1bedded (beds 

'are 1%-2 in. thick) ; weathers pinkish gray. (TP56-394) -------------- 5 

31. Dolomite, pale-red (5R 6/2), very fine 

grained ; contains about 10 percent 

silt-sized quartz particles; mediumlbedded (beds ~are 6-8 in. thick) ; 

wea,thers grayish red. ( TP56-393) -- 8 

30. Dolomite, pale-red ( 5R 6/2), very fine 

grained ; contains many very highly 

recrystallized Thamnopora skeletons ; 

thick-bedded; weathers reddish gray. 

TP56-392) ------------------------ 3 

29. Dolomite, yellowish-gray, fine-grained, 

thin-bedded; poorly exposed_________ 2 

119 

OumuZative 

thickness 

(feet) 

317 

316 

312 

305 

303 

298 

290 

287 
120 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 12.-Lost Tank Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

28. Dolomite, yellowish-gray ( 5Y 8/1), 

slightly calcitic, very fine to finegrained ; contains clouds of very fine 

grained dolomite surrounded by somewhat coarser grained material; contains very many highly recrystallized Am.phipora skeletons, most of 

which have lost their structure; very 

few scattered quartz grains· as much 

as 0.3 mm in diameter, subrounded ; 

thick-bedded; weathers light gray. 

( TP56-391) ---------------·---------

27. Dolomite, pale-red ( 5R 6/2) , fine- to 

medium-grained, saccharoidal, thickbedded; at 5-7 ft, large, calcite-filled 

vugs as much as 4 inches in diameter 

occur; weathers grayish red. (TP56- 381, 390) _________________________ _ 

26. Covered intervaL ___________________ _ 

25. Dol'omite, pale-red ( 5R 6/2), fine- to 

medium-grained, saccharoidal; contains a few scattered quartz grains 

as much a1s 0.3 mm in diameter, angular to sub angular ; thin-bedded to 

fiaggy; weathers pale red. (TP56-

380) ------------------------------ 24. Covered interval; slope covered with 

Sub-

'llnit 

thickness 

(feet) 

2 

11 

4 

5 

rubble of fine-grained light-gray 

thin- to medium-bedded dolomite____ 25. 

23. Dolomite, pale-red ( 5R 6/2), coarsely 

crystalline ; contains a few idiomorphic dolomite crystals; th:ick-bedded; 

weathers pale red with pitted surface. 

(TP56-379)________________________ 5 

22. Covered interval; probab!J.y mostly 

'light-gray fine-grained dolomi'te and 

·some coarser pinkish-gray dolom:ite__ 15 

21. Dolomite, pinkish-gray (5YR 8/1), calcitic, very sandy ; grades into sandy 

dolomite; thick-bedded; quartz 

gra:ins, very fine ·to fine ; gl"ains as 

much as 0.3 mm, angular oo subangul'ar, large or grains rounded 

to subrounded. Quartz grains make 

up 10 percent or more ·of the rock ; 

in places, they are eoncentra1ted so 

they are trghltly _r:m.cked to form sandy 

layers several millimeters thick ; scattered vugs of varying sizes as much 

as 10 mm in diameter, filled with pinki'sh to white calcite; weathe1~s iight 

gr•ay. ( TP56-378) ------------------ 3 

20. Sandstone, pinkish-gray ( 5Y R 8/1), medium- to coa.rse-grained; quartz 

graius mostly angular tJo subangular, 

s101me of the larger grains ~subrounded ; grains are tightly interlocked ; rock contains practically 

no matrix ; very th:ick bedded (beds 

as much as 7 ft thick) ; conspicuous 

Cumulative 

thickness 

(feet) 

285 

283 

272 

268 

263 

238 

233 

218 

SECTION 12.-Lost Tank Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

20. Sandstone, etc.-Continued 

Sub-

•unit 

thickness 

(feet) 

cliffs ; weathers light brown. ( H56-

133, 200)-------------------------- 27 

19. Covered.------·------------------------ 2 

18. Dolomite, light gray, very finely crystalline, silty and slandy; weathers into 

rounded ledges _____________________ - 7 

17. Sandstone, pale-red (5R 6/2) to pale 

red-purple (5P 6/2), medium- to 

coarse~grained, well-sovted, quartz 

gi"ains suhrounded to subangulnr, 

embedded in opaque matrix (possibly 

clay) ; friable; we'athers olive gray. 

(Fl56-131)_________________________ 5 

16. Dolomite, pale red-purple (5P 6/2) <to 

grayish-pink ( 5R 8/2) ; aphanitic; 

good conchoidal fracture; very uniform matrix with inSiignificant 

amounts of silt-sized detrital quartz 

grains and a few very small ('less 

than 1 mm) calcite vugs ; crops out 

in two thinly laminated cliff-forming beds; weathers yellowish gray. 

(II56-130, 129)-------------------- 22 

15. Dolomite, pinkish-gray ( 5Y R 8/1) 

aphanitic; conchoidal to subconcho1-

d!al fi"acture; scattered detrital quartz 

grains, mostly silt size to fine, 

and 'a few subrounded grtaillJS ·as 

much as 0.3 mm in diameter ; mediumto •thick-bedded (beds are 2-3 ft 

thick) ; weathers grayi'sh pink. 

(Fl56-128) ------------------------ 14 

14. Dolomite, grayish or.ange-pink (5YR 

7/2), subaphanitic; subconchoidal 

fracture; matrix in places breccious, 

containing clasts of aphanitic dolomite as much as 15 mm in diameter; 

abundant detrital quartz grains, ranging from silt size to about 1 mm in 

diameter, either scattered diffusely 

throughout the rock or concentrated 

in thin lenses or laminae ; large grains 

subrounded; medium-bedded (beds 

are 1-2ft thick) ; weathers yellowish 

Cumulative 

thickness 

(feet) 

215 

188 

186 

179 

174 

152 

gray. (II56-127)__________________ 13 138 

13. Sandstone, pale-red, dolomitic.; similar 

to subunit 9----------------------- 2 125 

12. Dolomite, medium-gray, aphanitic____ 2 123 

11. Sandstone, pale-red, poorly sorted (like 

subunit 9) ; fills fine cracks in underlying dolomite to depth of 1 ft_______ 0. 5 121 

10. Dolomite, medium-gray, aphanitic, thinly laminated ______________________ _ 

9. Sandstone, pale-red (RR 6/2), poorly 

sorted, fine- to coarse-grained ; larger 

quartz grains subrounded, smaller 

grains subangular to angular; small 

amount of dolomitic matrix. (II56-

126)-------------------------------

1 120.5 

0.5 119.5 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 121 

SECTION 12.-Lost Tank Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

8. Dolomite, banded grayish orange-pink 

(5YR 7/2) and light brownish-gray 

( 5 Y R 6/1) , sub a ph ani tic ; contains 

vugs as much as 5 mm long filled with 

red-tinted calcite; laminated, laminaSubunit 

thickness 

(feet) 

tion caused mainly by thin layers of 

detrital quartz grains, which ars sub--

rounded to subangular and range 

from silt size to about 1 mm in 

diameter; matrix contains aphanitic 

dolomite clasts as much as several 

millimeters in diameter. (H56-125) _ 2 

7. Sandstone, light-gray, poorly sorted, 

fine- to coarse-gl'lained; well-rounded 

coarse-grained clasts embedded in 

very fine matrix___________________ 1 

6. Dolomite, pale-red (5R 6/2), subaphanitic; subconchoidal fracture; contains as much as 3 percent detrital 

quartz grains, which are angular to 

subangular and as much as 0.7 mm in 

diameter; medium-bedded, hard; 

weathers grayish pink. (H56-124) -- 13 

Fetid dolomite unit: 

5. Dolomite, medium-gray, finely saccharoidal, thinly laminated_________ 3 

4. Dolomite, grayish-red (lOR 4/2), very 

finely crystalline ; small amount ( 1 

percent or less) of detrital quartz 

grains as much as 0.1 mm in diameter ; very thin bedded to fissile ; 

weathers pale reddish brown. (H56-

123)_______________________________ 3 

3. Dolomite, pale-red (5R 6/2), very finely 

crystalline, thinly laminated; insignificant amount of s:ilt-sized detrital 

quartz grains ; slightly fetid odor ; 

weathers pale red. ( H56-122) _ _ _ _ _ _ 13 

Beckers Butte Member : 

2. Dolomite and shale, interbedded, grayish-red, lenticular__________________ 1 

1. Sandstone, grayish-purple (5P 4/2) to 

pale reddish-brown (lOR 5/4) ; mostly 

medium grained, but contains many 

pockets of coarser material; generally 

thick bedded, although in places, irregularly bedded to fiaggy ; massive, 

cliff-forming; crossbedded___________ 83 

Precambrian: Mazatzal Quartzite. 

Cumulative 

thickness 

(feet) 

119 

117 

116 

103 

100 

97 

84 

83 

SEC'l'ION 13.-Southwest Branch of Lost Tank Canyon 

[East of Heber-Young High'Way, 0.8 mile south of turnoff to Lost Tank 

Canyon (Fort Apache Indian R£'servation, NW* sec. 3, T. 9 N., 

R. 15 E.). Photograph lots AK 3257, 3258. Measured by Curt 

Teichert, 1953; additional observations by Teichert, 1957] 

Martin Formation: Sub- Gumuunit lative 

Jerome Member : thick- thickUpper unit: (j;;:) tr!~~) 

24. Dolomite, slightly calcitic, grayish-pink 

(51?, 8/2), very finely crystalline; contains small calcite vugs; argillaceous; 

richly fossiliferous; in part, coquina 

of silicified brachiopods ( Theodoss,ia 

sp.) ; medium-bedded; weathers grayish pink. (T56-403)--------------- 32 

23. Dolomite, slightly calcitic, pale-red (5R 

6/2), very finely crystalline, argillaceous; contains rich silicified fauna 

( Cyrtospirifer cf. C. HJhitneyi, Schizophoria iowensis, Theodossia cf. T. 

hungertordi, Atr·ypa cf. A. devonica, 

Spinatrypa planosulcata) ; mediumbedded (beds are 8-10 in. thick) ; 

weathers into large very pale orange 

slabs. (T56-402)------------------ 26 

22. Dolomite, calcitic, mottled pale-red ( 5R 

6/2) and grayish orange-pink (5YR 

7/2), finely crystalline; few small calcite vugs ; pin-point porosity ; medium-bedded (beds are as much as 8 in. 

thick) ; weathers pale red___________ 3 

21. Dolomite, slightly calcitic, mottled palered (lOR 6/2) and grayish orangepink ( 5 Y R 7/2) , finely crys,talline ; 

contains small amount of detrital 

quartz grains in sizes 0.5 mm and 

less ; larger grains rounded ; very fossiliferous, containing abundant silicified branchiopods, mostly Theodossia 

cf. T. hunge,rfordi; medium-bedded; 

weathers yellowish gray. (T56-

40l)_______________________________ 5 

20. Dolomite, grayish-purple, coarsely crystalline, thin-bedded, poorly exposed_ 2 

19. Dolomite, calcitic, pale-red (5R 6/2), 

very fine grained, argillaceous, finely 

crystalline; fossiliferous, contains 

Aulocystis sp. or Syt·ingop01·a sp., 

Platyrachella cf. P. mcbridei, Cyrtospirifer sp., Spinatrypa planosulcata; thin-bedded; weathers pale 

red. (T280)_______________________ 2 

18. Sandstone, light-brown, fine-grained, becomes coarser toward top ; invertebrate tracks on bedding planes; thinbedded ; poorly exposed, except top 3 

feet, which is cliff forming__________ 36 

303 

271 

245 

242 

237 

235 

233 
122 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 13.-Southwest Branch of Lost T'ank Canyon-Con. 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

17. Limestone, biostromal, massive; consists of colonies of spherical and 

branching stromatoporoids (including 

?A_mphipora sp. and Idiostroma) 

and Alveolites sp.; scattered small 

calcispheres; comparatively little interstitial limestone matrix; at top of 

subunit, 2 ft. of brecciated limestone 

containing stromatoporoid fragments. 

Sub-

'll nit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

(~257)---------------------------- 11 197 

16. Limestone, light-gray, very finely crystalline, thick-bedded; grades into 

subunit 17------------------------- 4 186 

15. Sandstone, pinkish-gray, mediumgrained, medium-bedded____________ 9 182 

14. Sandstone, yellowish -gray ( 5 Y 8/1) , 

very fine grained, well-sorted, thinbedded; weathers light olive gray. 

(T256) ---------------------------- 4 173 

13. Covered ----------------------------- 10 169 

1?... Sandstone, pinkish-gray (5YR 8/1), 

very fine grained, well-sorted; fucoidal structures; thick-bedded; 

weathers brownish gray. ('T255) ___ _ 

11. Dolomite, very finely crystalline, 

thin-bedded (beds are 4-6 in. thick) ; 

weathers medium gray--------------

10. Dolomite, pale-red, very finely crystalline, thin-bedded; weathers pale red __ 

9. Covered ----------------------------- 8. Dolomite, grayish-red ( 5R 4/2), very 

finely crystalline; contains abundant 

Amphipora sp. and Thamnopora sp. ; 

thick-bedded; weathers pale red. 

(T254) ---------------------------- 7. Dolomite, grayish red-purple ( 5RP 4/2), 

very finely crystalline, subconchoidal 

fracture; thin-bedded; weathers light 

olive gray. ( T253) -----------------

6. Dolomite, very slightly calcitic, mottled 

pale-red ( 5R 6/2) and grayish-pink 

( 5R 8/2), coarsely crystalline ; contains hypidiomorphic dolomite crystals and little interstitial calcite; 

lower half thin-bedded (beds are 

4-6 in. thick), upper half, medium 

bedded (beds are as much as 1 ft 

thick) ; weathers pale red; poorly 

2.5 159 

2.5 156.5 

3 154 

10.5 151 

14.5 140.5 

18.5 126 

exposed. (T252)------------------- 32 107.5 

Aphanitic dolomite unit : 

5. Dolomite, light-gray ( N 7), aphanitic; 

scattered detrital quartz grains, 

rounded, as much as 1 mm in diameter; thin-bedded; weathers yellowish gray. (T251)------------------ 16.5 75.5 

4. Dolomite, pinkish-gray ( 5Y R 8/1), ve·ry 

finely crystalline; abundant detrital 

quartz, as much as 1 mm in diameter, 

poorly sorted ; grais rounded to sub--

rounded; thin-bedded; weathers yellowish gray. (T250) -------------- 4 59 

SECTION 13.-Southwest Branch of Lost Tank Canyon-Con. 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

3. Covered, surface strewn with sandstone 

Subunit 

thickness 

(feet) 

OumulaU'Ve 

thickness 

(feet) 

and dolomite boulders_______________ 85 55 

2. Dolomite, light-gray (N 8), very finely 

crystalline ; contains abundant detrital quartz, poorly sorted, as much as 

1 mm in diameter ; grains subrounded 

to rounded. (T249) ----------------

1. Dolomite, light-gray, -aphanitic; scattered detrital quartz; bedding not well 

exposed; weathers medium gray ____ _ 

10 20 

10 10 

NOTE.-Below subunit 1, the slope is covered with talus composed of light-gray aphanitic dolomite for 45 ft. Farther down, the talus 

consists of brC)wn sandstC)ne. No outcrops occur in this sandstone 

subunit, and its base is not exposed. 

SECTION 14.-West bank of Canyon Greek 

[2 miles south of 0. W. Ranch (Tonto National Forest, NE~SWlA, sec. 

15, T. 1072 N. R. 15 E.). Photograph lots AK 3166, 3167. Measured 

by R. L. Harbour, 1956] 

Martin Formation : 

Jerome Member : 

Upper unit: 

27. Dolomite, pale-red ( 5R 6/2), very 

finely and uniformly crystalline ; contains a little detrital quartz, ranging 

mostly from silt to fine in grain size 

a few grains of which are as much 

as 0.3 mm in diameter; contains fragments of Atrypa sp. and Platyrachella cf. P. tncbr·idei. (H56-119) __ 

26. Covered -----------------------------

25. Dolomite, light-gray (N 7), very finely 

crystalline; contains abundant detrital quartz grains ranging from silt 

Sub- Oumuunit Zative 

thick- thick- ness ness (feet) (feet) 

5 143 

7 138 

to very fine in grain size; laminated; 

slope-forming. (H56-118) ----------- 5 131 

24. Dolomite, grayish orange-pink (lOR 

8/2), very finely crystalline; contains 

abundant det~ital quartz ranging in 

size from silt to about 0.7 mm in diameter ; larger grains rounded to subrounded; comparatively little etching 

of grains; detrital quartz constitutes 

as much as 25 percent of the rock; 

lower half of subunit flaggy, upper 

half is one undivided bed; weathers 

pale orange. (H56-117)------------ 7 126 

23. Limestone, medium light-gray (N 6), 

aphanitic; contains aboundant individual crystals and small clusters of 

calcite and abundant detrital quartz 

grains, ranging from silt to about 2 

mm in diameter in grain size, whose 

surface more or less heavily etched; 

contains few calcispheres; crops out 

in two laminated resistant beds; 

weathers light gray. (H56-116) _____ 4 

22. Dolomite, pinkish-gray ( 5Y R 8/1) , 

finely crystalline, very sandy ; in part 

grades into sandy dolomite; detrital 

quartz grains abundant in all size 

grades ranging from silt to 1 mm in 

119 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 123 

SECTION 14.-Wes't bank of Canyon Greek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

22. Dolomite, etc.-Continued 

diameter ; all grains about 0.5 mm 

are well rounded, outer surfaces 

slightly etched; very thin bedded; 

slope-forming: weathers light brownish gray. ( H56-115) ----------------

21. Dolomite, pinkish-gray, finely and evenly crystalline; subunit and underlySub-

·unit 

thickness 

(feet) 

7 

ing subunit form cliffs______________ 2 

20. Siltstone, gray, dolomitic, resistant_____ 1 

19. Dolomite, light brownish-gray (5YR 

6/1), very finely crystalline to aphanitic; contains very small amount of 

silt sized quartz grains ; mediumbedded beds about 1 ft thick separated by shale bands as much as 3 

in. thick; slope-forming; weathers 

pale brown. (H59-114) ------------- 10 

18. Covered ----------------------------- 2 

17. Siltstone, gray, dolomitic; contains medium-sized quartz grains near base ; 

contains one slightly laminated bed__ 4 

16. Dolomite, pale-red, saccharoidal; contains one resistant somewhat laminated bed----------------·--------- 4 

15. Sandstone, gray, medium-grained, dolomitic, friable_______________________ 3 

14. Siltstone, grayish-red, dolomitic, resistant-------------------------------- 2 

13. Dolomite, pale-red (5R 6/2), very finely 

and uniformly crystalline ; forms one 

bed; weathers grayish red. (H56-

133) ------·------------------------- 4 

12. Dolomite, pinkish-gray ( 5Y R 8/1), very 

finely and uniformly crystalline; contains very small amount of silt sized 

detrital quartz grains; scattered calcite vugs as much as 15 mm in diameter; medium-bedded (beds are 1 

ft thick) ; slope-forming; weathers 

pale yeUowish brown. (H56-112) ___ 8 

11. Dolomite, pale-red (5R 6/2), fine- to 

medium-crystalline, saccharoidal; 

consi.Jsts of aggregate of idiomorphic 

and hypidiomorphic dolomite crystals; thick-bedded (maximum thickness of beds, 5 ft) ; weathers pale 

red. (H56-lll) ------------------- 12 

10. Dolomite, grayish orange-pink (5YR 

7 /2), very finely crystalline to 

aphanitic; matrix contains irregularly 

disseminated clusters and veinlets of 

crystalline calcite; subunit contains 

small lenses and laminae of detrital 

angular quartz grains ranging in size 

from silt to about 0.4 mm in diameter; indistinctly laminated but has 

no well-defined bedding; weathers 

light brown. (H56-110) ------------ 7 

CumuZatit•e 

thickness 

(feet) 

115 

108 

106 

105 

95 

93 

89 

85 

82 

80 

76 

68 

56 

SECTION 14.-West bank of Canyon Greek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Sub-

'unit 

thickUpper unit-Continued (j;!:) 

9. Dolomite, pale-red ( 5R 6/2), very finely 

and uniformly crystalline ; contains 

scattered calcite vugs as much as 15 

mm in diameter; crops out as one 

ledge-forming bed. (H56-109) ------ 2 

8. Dolomite, sandstone, interbedded with 

shale and sandy dolomite, pale-red 

( 5R 6/2), poorly sorted ; contains 

quartz grains ranging in size from 

silt to 1.5 mm in diameter; smaller 

grains angular to subangular, larger 

grains rounded to subrounded; shaly 

layers, brownish-red; thin-bedded 

(beds are as much as 4 in. thick) ; 

weathers grayish pink. (H56-108) __ 2 

7. Dolomite, pale-red (5R 6/2), coarsely 

crystalline, saccharoidal ; consists of 

idiomorphic and hypidiomorphic dolomite crystals as much as 1 mm indiameter; contains as much as about 3 

percent detrital quartz grains ranging 

in size .from silt to about 1 mm in 

diameter; contains larger grains that 

are generally subangular; mediumbedded (beds are 1-2 ft thick) ; 

weathers pale red. (H56-107) ------ 13 

6. Sandstone, gray-tinted, poorly sorted, 

fine- to coarse-grained ; contains redtinted clay partings ___ ._____________ 3 

5. Sandstone, pinkish-gray (5YR 8/l) to 

pink (5RP 8/2), medium-grained, 

poorly sorted; contains quartz grains 

ranging in size from silt to 0.7 mm 

in diarueter ; as much as 20 percent 

dolomitic matrix; contains a resistant 

bed ; weathers pale brown. ( H56-

105)-------------------------------

4. Dolomite, calcitic, pale-red ( 5R 6/2), 

very silty and sandy ; contains detrital quartz grains, ranging in size 

from silt to 1 mm in diameter, and 

making up 5-10 percent of rock ; 

larger grains well rounded to subrounded; matrix of medium- to 

coarse-grained dolomite crystals and 

interstitial calcite ; massive, slope 

forming. (H56-105, 104, 103) ------

3. Covered; probably mudstone _________ _ 

2. Sandstone, pale-red ( 5R 6/2), poorly 

sorted, medium- to coarse-grained ; 

somewhat laminated; larger quartz 

grains subrounded to rounded ; 

smaller grains subangular to angular, 

tightly packed, and interlocking. 

(H56-102)-------------------------

1. Mudstone, red-tinted, poorly exposed--

Precambrian: Dripping Spring Quartzite. 

1 

24 

0.5 

3 

0.5 

Cumulative 

thickness 

(feet) 

49 

47 

45 

32 

29 

28 

4 

3.5 

0.5 
124 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 15.-East side of Canyon Creek 

[1 mile S·Outh of 0. W. Ranch (Tonto National Forest, SE74,NW?4 sec. 

10, T. 101h N., R. 15 E.). Photograph lots AK 3166, 316<7. Measured 

by Curt Teichert, 1956] 

Martin Formation: 

.Jerome Member : 

Upper unit: 

24. Limestone, grayish-red ( 5R 4/2), dolomitic, medium-grained, slightly 

sandy; scattered quartz grains make 

up 1-2 percent of rock and grade in 

s·ize from very fine to fine; grains 

larger than 0.2 mm generally well 

rounded; medium-bedded (beds are 

6-12 in. thick) ; weathers grayish red. 

Subunit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

(T56-371) -------------·------------ 6 133 

23. Limestone, pinkish-gray ( 5Y R 8/1) to 

yellowish-gray ( 5Y 8/1), very fine 

grained, very sandy : quartz grains 

make up 10-30 percent of rock, mostly 

in size grades ranging from very fine 

to medium ; a few grains are coarse ; 

small grains are angular to subrounded ; large grains tend to be well 

rounded; calcareous matrix, calcarenitic, consis,ting of well-rounded 

grains of very fine grained limestone 

cement containing fine-grained calcareous material ; contains a very few 

brachiopod remains ; thick-bedded, 

weathers pinkish gray. ( T56-370) __ _ 

22. Sandstone, pale-red ( 5R 6/2), mediumto coarse-grained; has irregular lamination indicating a rough separation 

of the medium and coarse fraction ; 

cement, clayey to silty, somewhat 

limonitic: grains as much as about 

0.3 mm in diameter are angular to 

subangular ; larger grains tend to be 

better rounded: thin-bedded; weathers pale red. (T56-369) ___________ _ 

21. Limestone, light brownish-gray ( 5}-R 

6/1), speckled medium-gray, finegrained, very sandy, thick-bedded 

(beds are 2 ft thick), laminated; 

quartz grains range in size from very 

fine to medium ; smaller grains angular ; larger grains subrounded to 

rounded ; quartz grains make up 10-

30 percent of rock; weathers light 

gray. (T56-368) ----------------

20. Limestone, light olive-gray (5Y 6/1), 

very fine grained; contains scattered 

euhedral dolomite crystals and irregularly distributed quartz grains ranging in s·ize from very fine to medium ; 

larger quartz grains frosted; wellrounded; locally, the quartz grains 

may make up 10 percent of the rock 

3.5 127 

2 123.5 

4 121.5 

but are generally rarer; weathers 

light gray. (T56-367) -------------- 1 117.5 

SECTION 15.-East side of Canyon Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

19. Sandstone, grayish-pink ( 5R 8/2), 

medium- to coarse-grained; contains 

much calcitic matrix ; quartz grains 

range from 0.05-0.5 mm in diameter, 

some are larger; small grains subangular; larger grains subrounded to 

rounded, most are rounded ; some 

grains show slight calcite replacement; matrix entirely calcitic; weathers light gray. ( T56-366) _________ _ 

18. Limestone breccia, light-gray (N 7), 

biostromal, unbedded, nodular appearance; contains angular limestone 

fragments as much as 3 in. in diameter; contains stromatoporoid colonies 

in place (A_cfinostrom.a sp.) as much 

as 12 in. in diameter; contains much 

organic fragnwntal material, including Thamnopora; weathers light gray. 

(T56-365) ------------------------- 17. Covered interval ____________________ _ 

16. Limestone, yellowish-gray ( 5Y 8/1), 

very fine grained, sandy; contains 5-

20 percent very fine quartz grains; 

matrix predominantly calcitic, containing scattered euhedral dolomite 

crystals; thin- to medium-bedded 

(beds are 2-12 in. thick) ; weathers 

light brown to gray. (T56-364) ___ _ 

15. Dolomite, pale-red (5R 6/2), slightly 

mottled yellow, medium-grained, saccharoidal, calcitic; calcium-rich material found along boundaries of irregularly shaped and interlocking dolomite crystals; thick-bedded; weathers reddish brown. (T56-363) _____ _ 

14. Dolomite, pinkish-gray ( 5Y R 8/1), 

medium-grained, calcitic, very sandy; 

quartz grains range in size from very 

fine to fine; contains a scattering of 

coarser grains as much as 1 mm in 

diameter ; smaller grains, angular to 

subangular; larger grains, subrounded 

to rounded ; quartz grains make up 

20-25 percent of the rock ; most 

larger grains have slight marginal 

replacement by dolomite ; thin- to 

medium-bedded; weathers pale red. 

Sub1tnit 

thickness 

(feet) 

6 

6 

8 

10 

5 

(T56-362) ------------------------- 16 

13. Dolomite, pale-red ( 5R 6/2), fine- to 

medium-grained, saccharoidal, very 

sandy ; much of the rock is an intimate mixture of fine-grained dolomite 

and small quartz grains, both about 

0.05 mm in diameter ; larger quartz 

grains sea ttered through the rock are 

as much as 1.0 mm in diameter and 

have marginal dolomite replacement; 

Cumulative 

thickness 

(feet) 

116.5 

110.5 

104.5 

96.5 

86.5 

81.5 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 125 

SECTION 15.-East side of Canyon Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

13. Dolomite, etc.-Continued 

quartz grains make up 20-50 percent 

of the rock. Vugs having irregular 

shape and size are common ; they are 

lined with yellow calcite but are mostly hollow; weathers pale red. ( T56-

Subunit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

361) ------------------------------ 12 65.5 

12. Dolomite, grayish orange-pink (lOR 

8/2), fine-grained, finely porouspores geneDally less than 0.3 mm in 

diameter, rarely larger-flaggy ; 

\veathers pale red__________________ 7 53.5 

11. Dolomite, grayish orange-pink (lOR 

8/2), fine-grained, sandy, grades into 

dolomitic sandstone; quartz grains 

making up 20-60 percent of the 

rock in different parts; graded bedding in about l-in. layers indicated. Dolomite is much finer grained 

than that in subunits 3, 5, 7, and 9; 

quartz grains have similar appearance 

and were subjected to dolomite replacement. Medium-bedded, laminated; contains some small-scale 

slump structures; weathers light 

brown_____________________________ 7.0 46.5 

10. Dolomitic shale, grayish-red___________ 0. 5 39. 5 

9. Dolomite, pale-red ( 5R 6/2), coarsegrained saccharoidal, very sandy ; 

quartz grains make up 40-50 percent 

of rock. Except for larger percentage 

of sand, this rock is similar in appearance to that of subunits 3, 5, and 7. 

(T56-358) -------------·------------ ·i. 5 39 

8. Sandstone, pinkish-gray ( 5Y R 8/1), 

very fine to fine-grained, laminated; 

has a general alteration of very fine 

grained and fine-grained laminae, 

each of which is about 2.5-3.5 mm 

thick ; smaller grains, angular to subangular ; large grains tend to be subrounded; no cement; weathers very 

light brown. (T56-357) ----------- 3 34. 5 

7. Dolomite, pale-red ( 5R 6/2), coarsegrained, saccharoidal ; consists in part 

of idiomorphic dolomite crystals ; 

megascopic appearance similar to that 

of subunits 3 and 5. (T56-356) _____ 2. 5 31.5 

6. Sandstone, pinkish-gray (5YR 8/1) ; 

identical with subunit 4. (T56-355) _ 1. 5 29 

5. Dolomite, pale-red ( 5R 6/2), coarsegrained, saccharoidal, very sandy ; 

megascopic and microscopic appearance identical with that of subunit 3. 

SECTION 15.-East side of Canyon Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

5. Dolomite, etc.-Continued 

( T56-354) --------------------------

4. Sandstone, pinkish-gray ( 5Y R 8/1), 

generally fine grained; contains sprinkling of larger grains as much as 

1.5 mm in diameter; small grains, angular to subangular, tightly packed, 

containing very little dolomitic cement ; larger grains subrounded ; 

thin-bedded to platy; weathers pinkSub-

'Unit 

thickness 

(feet) 

1 

Cumulative 

thickness 

(feet) 

27.5 

ish gray. (T56-353)_______________ 2 26.5 

3. Dolomite, pale-red (5R 6/2), coarsegrained, saccharoidal, very sandy. 

Quartz grains make up 10-15 percent 

of rock and were originally angular to 

subangular but are in process of being replaced by dolomite; hence, 

most quartz grains are now quite irregular in shape; their size ranges 

from very small to about 1.5 mm in 

diameter. Thick-bedded ; weathers 

pale red. (T56-352)_______________ 2.5 24.5 

2. Sandstone, pinkish-gray (5YR 8/1), 

mottled light-brown (5YR 6/4) ; 

poorly sorted in the fine- to coarsegrain range; quartz grains tightly 

packed, mostly angular to subangular, 

some subrounded ; rock contains practically no cement ; thin-bedded, softer 

than subunit 1; has porous bands; 

weathers brownish gray. (T56- 351) __________________ ., ____________ lG 22 

1. Sandstone, pale-purple (5P 6/2), medium-grained quartzose; grains angular to subangular; tightly packed; 

rock contains practically no cement; 

thick-bedded, hard; has slight indications of crossbedding; weathers dark 

gray. Rests unconformably on Dripping Spring Quartzite; contact irregular and thickness of subunit ranges 

from 1 to 6ft. (T56-350)__________ 6 6 

SECTION 16.-Naeglin Rirn 

[Gila County (Tonto National Forest, NE1,4 sec. 23, T. 10 N., R. 14 E.), 

Measured by Curt Teichert and R. L. Harbour, 195,6] 

Martin Formation: Sub- Cumuunit lative 

Jerome Member : thick- thickUpper unit: /}:;:) tJ::~) 

20. Limestone, grayish orange-pink (5YR 

7/2) to grayish-orange (lOYR 7/4); has 

irregularly distributed dark spots; 

dense ; conchoidal fracture ; small 

amount of silt-sized quartz particles 

scattered throughout the rock; few silicified brachiopods (spiriferids) ; flaggy ; 

weathers light brown ; generally similar 

to subunit 18. (T56-422) ------------- 8 197 
126 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 16.-N aeglin Rim--Continued 

Martin Formation-Continued ~:;i~- ~~;?:; 

Jerome Member-Continued t!!~~- ~;~:-

Upper unit-Continued (feet) (feet) 

19. Covered intervaL_______________________ 7 189 

18. Limestone, dolomitic, pale-red (lOR 6/2) ; 

fine grained, contains very few detrital 

(1uartz grains as large as 1 mm ; fiaggy ; 

weathers light brown. (T56-421) _____ 11 182 

17. Sandstone, white, medium-grained, quartzose, poorly exposed__________________ 1 171 

16. Limestone, slightly dolomitic, moderate 

reddish-orange (lOR 6/6) ; very fine 

grained ; subconchoidal fracture ; contains an abundance of silicified shells of 

Theodossia; thick bedded ; weathers 

grayish pink. ( T56-420) ------------- 14 170 

15. Limestone, light-gray (N 7) to medium 

light-gray ( N 6) ; dense ; subconchoidal 

to conchoidal fracture; laminated, in 

places slightly brecciated; contains a 

small amount of idiomorphic dolomite 

crystals ; microstylolites are well formed 

but poorly exposed. (T56-419) -------- 4 156 

14. Covered intervaL_______________________ 12 152 

13. Sandstone, white to pinkish-gray (5YR 

8/1) , :fine grained ; composed of a mosaic 

of tightly interlocking detrital quartz 

grains, which are angular to subrounded ; almost no cement; mediumbedded ; weathers pinkish brown; poorly 

exposed. (T56-418)__________________ 5 140 

12. Dolomite, pale-red, fine grained, saccharoidal; fiaggy; contains small calcitefilled vugs and calcite stringers ; weathers light gray------------------------- 11. Covereu interval _______________________ _ 

10. Dolomite, pale-red (5R 6/2), dense to very 

:fine grained, very homogeneous ; subconchoidal fracture; thin-bedded (beds are 

4-8 in. thick) ; weathers yellowish 

3 135 

6 132 

brown. (T56-417, 416)---------------- 14 126 

9. Dolomite, light~gray (N 7), very fine 

grained, sandy; oontains detrital quartz 

grains ranging in size from snt to as 

much as 1.5 mm in diameter; detrital 

quartz makes up ·a's much as 10 percent 

of rock ; grains mostly subangular to subrounded, some grains well rounded ; 

most grains were peripherally attacked 

by dolomite aUhough generally not to the 

extent as in 'Subunit 8; ~thin- to mediumbedded; lower 1 fit has a vuggy porosity, 

some ·of the larger vugs are filled with 

brown calcite ; uppermost 3 fit more sandy 

than the rest and has a 'brecciated dolo .. 

mite matrix; wea.1thers orange gray; 

generally poorly exposed. ( T56-415) -- 15 112 

8. Dolomite, light olive-gray ( 5Y 6/1), very 

fine to fine-grained, very sandy; quartz 

grains as much as 3 mm in diameter, most 

·are ·about 0.5 mm in size; original shape 

of most grains ~subrounded, but nearly 

SECTION 16.-N aeglin Rim-Continued 

Martin Forma tion~Continued 

Jerome Member-Continued 

Upper unit-Continued 

8. Dolomite, etc.-Continued 

Sub- Oumuunit lative 

thick- thick- ness ness (feet) (feet) 

all are per'ipherally replaced by dolomite 

and their margins appears angular and 

j•agged; d~trttal quartz may make up as 

mueh as 25---30 percent of the rock; 

matrix generally 'a dolomite breccia 

containing penecontemporaneous pebbles 

as much a'S 1% inches in dmmeter; 

upper 5 ft has a few calcite vugs·; thickbedded (beds are 1% ft thick), in part 

laminated; weathers orange gray. (T56- 414, 413) _____________________________ 14 97 

7. Dolomite, mottled light brownish-gray 

(5YR 6/1) and light olive-gray (5Y 

6/1) ; very fine to fine-grained ; eontJa.ins 

very few scattered detritJal fine quJa.<:r'tz 

grains ; some beds contain small penecontemporaneous dolomi·te pebbles; up--

per part has large calcite vugs as much 

as 1% in. long and % in. wide ; generally thin bedded ; s'ome fiaggine'SIS 

formed in the upper half; at 36-38 ft, 

highly recrystallized tube- or rodlike 

structural features are found tha1t are 

probably dolomitized skeletons of Amphipora,· entire unit is remarkably uniform in lithology and appearance ; 

weathers grayish orange to yellowish 

gray. (T56-412, 411, 410)____________ 43 83 

6. Dolomi·te, mottled very light gray ( N 8) 

to light-gray (N 7) to grayish-pink 

( 5R 8/2) ; on the whole, very fine 

grained, 'but 'in most parts highly brecciated; eonsiSIDs of rolled dolomite fragments varying in 1size to as much a'S several inches in di'ameter ; some smaller 

fl"agments have concentric layering suggesting ooid!s ; matrix 'between fragments, largely ·recrystallized, composed 

mos.tly of calcite, but shows some later 

dolomitiz!ation; general sprinkling of 

quartz grains, most less ·than 0.5 mm in 

diameter, subangular ·tJo rounded; many 

quartz grains have slight marginal replacement by dolomite; in places, detr'i-

•t·al quartz grains form sandy layers and 

pockets; in outcrops·, the rock has a 

thick-bedded appearance, although it 

lacks cleHrly defined bedding planes ; it 

weathers as large rounded knoUs resembling biohermal structures, but no organic constituents are in evidence; 

weathers medium light gray to pinkish 

gray. (T56-409) ---------------------- 12 40 

5. Dolomite, pinkish-gray (5YR 8/1), very 

fine grained, sacchal"oidal, thick-bedded; 

weathers reddish brown; poorly exposed-------------·-------------------- 3 28 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 127 

SECTION 16.-Naeglin Rim-Continued 

Martin Formation-Continued Sub- Oumuunit lative 

Jerome Member-Continued thick- thick- ness ness Upper unit-Continued (feet) (feet) 

4. Dolomite, grayish orange-pink (lOR 8/2), 

dense, but has irregularly angular fracture; highly and closely jointed; detrital 

quartz grains present, generally fine, but 

locally medium in pockets and layers ; 

scattered pebbles as much as 1 in. in diameter; some vugs as much as 10 mm in 

diameter filled with clear calcite; thinbedded, except uppermost 2 ft, which is 

medium bedded (beds are 10 in. thick) ; 

weathers brownish gray. (T56-408, 

407)---------------------------------- 7 25 

3. Covered interval________________________ 5 18 

2. Dolomite, grayish-pink (5R 8/2) to grayish orange-pink (lOR 8/2), very fine 

grained to fine-grained-the fine-grained 

portion is saccharoidal-scattered detrital quartz particles, generally of silt size 

but as much as 0.4 mm in diameter, subangular to rounded; appearance nodular; 

has no distinct bedding; weathers light 

brown. (T56-406)____________________ 5 13 

1. Sandstone, yellowish-gray ( 5Y 8/1) , medium- to fine-grained; is a mosaic of 

tightly interlocking detrital quartz 

grains, which are slightly deformed and 

generally subangular to angular ; thinbedded (beds are about 6 in. thick) ; 

weathers yellowish brown. (T56-405) __ 8 

Precambrian : Dripping Spring Quartzite. 

SECTION 11.-Upper Colcord Oanyon 

8 

[Tonto National Forest, NW1MNE1M sec. 15, T. 10% N., R. 14 E.). 

Photograph lots AK 3168, 3169. Measured by Curt Teichert, 1953 ; 

with revisions, 1956] 

Martin Formation : 

Jerome Member : 

Upper unit: 

21. Limestone, dolomitic, yellowish-gray 

(5Y 7/2), fine grained; contains silicified crinoid stems and fragments of 

Platyrachella at about 4 ft; contains 

scattered large vugs as much as 2 em 

in diameter filled with white calcite; 

medium-bedded; weathers yellowish 

gray. ( T56-446) ------------------

20. Sandstone, grayish orange-pink ( 5R 

7/2), fine-grained to silty ; large percentage of matrix is slightly calcitic 

dolomite. The bulk of the detrital 

quartz is of silt to very fine grain size; 

the grains are angular ; scattered 

among them are larger grains, commonly as much as 0.5 mm in diameter, 

exceptionally as much as 1 mm ; large 

grains more rounded, some of the 

larger grains have slightly corroded 

edges as seen in cross section. Thinbedded to fiaggy; weathers light 

brown. (T56-445) -----------------

Sub-

'unit 

thickness 

(feet) 

Oumulative 

thickness 

(feet) 

11.5 222 

9 210.5 

SECTION 11.-Upper Colcord Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

19. Dolomite, slightly calcitic, pale-red ( 5R 

6/2), medium-grained; contains many 

Amphipora colonies, whose skeletons 

are completely replaced by crystalline 

calcite and dolomite; the material replacing the Amphipora skeletons is 

light in color value and the rock appears mottled, beds generally appear 

thick-bedded but break into thinner 

beds where highly weathered; weathers pale red. (T-302) --------------

18. Siltstone, contains dolomitic limestone 

matrix; very light gray (N 8) ; carbonate matrix very fine grained to 

dense. Silt particles are in places 

tightly packed ; in other places, the 

particles make up less than 50 percent of the rock; this unit is thus on 

borderline between a calcareous siltstone and an argillaceous limestone. 

Beds contain brachiopod fragments; 

thin-bedded beds ( 4-8 in. thick) ; 

weathers light brown. (T56-444) __ 

17. Limestone, light brownish-gray ( 5R 

6/1) ; very fine grained; subconchoidal fracture ; rich in tintinnids ( ? ) , 

calcispheres and ostracodes ; thinbedded; weathers moderate brown. 

Subunit 

thickness 

(feet) 

9 

Oumulative 

thickness 

(feet) 

201.5 

3.5 192.5 

( T56-443) -----------------·-------- 2 189 

16. Siltstone, mixed with dolomitic limestone matrix, pale-red (lOR 6/2) ; 

carbonate matrix, very fine grained 

and in places makes up as much as 50 

percent of the rock; detrital quartz 

predominantly silt size, but beds contain scattered well-rounded grains 

about 0.2-mm in diameter; thickbedded; massive; weathers pale red. 

(T56-442)-------------------------

15. 

14. 

Covered intervaL ___________________ _ 

Limestone, probably slightly dolomitic, 

very sandy, mottled orange-pink (5YR 

8/4) and grayish-pink (5YR 8/2) ; 

very fine grained carbonate matrix 

containing abundant very poorly 

sorted detrital quartz grains ; the 

grains range in size from silt to about 

1 mm in diameter ; larger grains are 

subrounded to well rounded ; very 

little carbonate replacement or etching of the quartz; because of the high 

content of quartz grains, the megascopic appearance of rock is like sandstone, although detrital quartz probably rarely exceeds 30 percent of rock ; 

thin-bedded; weathers orange pink. 

(T56-441)-------------------------

5.5 187 

1.5 181.5 

2 180 
128 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 17.-Upper Colcord Canyon-Continued 

Martin Forma tion~Oontinued 

Jerome Member-Continued 

Upper unit-Continued 

13. Dolomite, very slightly calcitic, palered (5R 6/2) ; very fine grained; contains abundant detrital quartz grains 

ranging in size from silt to about 0.5 

mm in diameter ; larger grains subrounded to well rounded; detrital 

quartz tends to be concentrated in 

layers, giving the rock a slightly laminated appearance; the quartz generally does not exceed 3-! percent of 

the rock, although it is more highly 

concentrated in scattered thin layers 

of dolomite sandstone; thin-bedded 

to platy; weathers pale red. (T56---

Sub-

•unit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

440) ------------------------------ 11 178 

12. Dolomite, pinkish-gray (51'R 8/1) ; very 

fine grained, irregularly laminated ; 

consists of a ground mass of dense 

dolomite containing large numbers of 

idiomorphic or hypidiomorphic dolomite rhombs as much as 0.05 mm in diameter; a few silt-sized detrital 

quartz particles probably make up 1-2 

percent of the rock ; thick-bedded; 

weathers yellowish gray. (T56-439) _ 22. 5 167 

11. Dolomite. calcitic in spots, pale-red 

(5R 6/2) to lOR 6/2), fine grained; 

110 detrital quartz ; thick-bedded, massive, hard; weathers pale red. 

(T56-438) ------------------------- 22 

10. Covered interval_____________________ 11 

9. Dolomite, pale-red ( 5R 6/2), very fine 

grained; contains a few silt-sized detrital quartz particles, which are 

fairly evenly distributed and make up 

about 3-4 percent of the rock ; thinbedded; weathers pale red. (T56--- 437) _______________________________ 11 

8. Covered interval_____________________ 5.5 

7. Dolomite, very slightly calcitic, mottled 

pale-red (5R 6/2) and pinkish-gray 

( 5YR 8/1), fine-grained ; ~ontains no 

detrital quartz ; upper part contains 

calcite stringers; medium-bedded. 

144.5 

122.5 

111.5 

100.5 

(T56-436) _________________________ 10.5 95 

6. Dolomite, grayish-pink (5R 8/2) to palered (5R 6/2) : fine grained; tends 

to be saccharoidal in upper part ; contains no detrital quartz particles ; 

medium- to thick-bedded (beds are 

6 in. to 2 ft thick) ; weathers pale red. 

(T56-435) _________________________ 21.5 84.5 

5. Dolomite, pale red-purple (5RP 6/2), 

very fine grained ; subconchoidal fracture; contains very scattered detrital 

quartz, mostly of silt size, and scattered grains as much as 0.5 mm in 

diameter, generally subangular ; detrital quartz composes not more than 1 

percent of rock; medium-bedded; 

weathers pale orange. (T56-434) __ 16 63 

SECTION 11.-Upper Colcord Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

4. Dolomite, slightly calcitic, pinkish-gray 

(51'R 8/1), very fine grained, contains 

some scattered detrital :fine quartz 

grains; matrix dense; quartz grains, 

angular to subrounded, making up 1-2 

percent of· the rock mass; contains 

abundant calcite stringers parallel to 

bedding as much as Ys-in. thick; medium-bedded; weathers pinkish-gray. 

Subunit 

thickness 

(feet) 

(T56-433) --------·----------------- 6 

3. Covered intervaL____________________ 24 

2. Dolomite, very slightly calcitic, grayish 

orange-pink (5YR 7/2), very fine 

grained ; subconchoidal fracture ; contains sea ttered grains of detrital 

quartz ranging in size from silt to 

medium ; smaller grains angular, 

larger grains subrounded to well 

rounded ; detrital quartz may make 

up as mueh as 5 percent of rock; medium-bedded; weathers grayish 

orange. ( T56-432) ---------------- 9 

1. Sandstone, grayish-pink (5R 8/2), fine 

grained; matrix contains scattered 

pebbles as much as 15 mm in diameter, especially in lowermost 12 in., 

which appears to be a breccia composed of angular quartzite fragments; 

contains a small amount of slightly 

calcitic dolomite as cement; medium 

quartz grains are generally well 

rounded to subrounded, larger and 

smaller grains tend to be angular to 

subangular ; medium-bedded, weathers brown. (T56-431)_____________ 8 

Precambrian : Dripping Spring Quartzite. 

SECTION 18.-Two miles south of Turkey Peak 

Oumulative 

thickness 

(feet) 

47 

41 

17 

8 

[Gila County (Tonto National Forest, NW% sec, 5, T. 10 N., R. 14 E.). 

Photograph lots AK 3168, 3169. Measured by R. L. Harbour, 1956] 

Martin Formation: 

Jerome Member : 

Upper unit: 

Sub- Oumuunit lative 

thick- thick- ness ness (feet) (feet) 

22. Covered_________________________________ 5 199 

21. Limestone, pale-red (5R 6/2), very fine 

grained; contains vugs as much as 1 em 

in diameter filled with brown calcite; 

contains abundant silicified fossils 

( Tharnnopora sp., Atrypa sp., Schizophoria sp.). (H56---150) ------------------ 2 194 

20. Covered_________________________________ 11 192 

19. Dolomite, calcitic, moderate orange-pink 

( 5Y R 8/4), very finely crystalline ; densely spotted by small iron s·tains ; small 

amount of silt; scattered crinoid stems 

as much as 12 mm in diameter; fissile; 

weathers grayish ·orange. (H56---149) --- 1 181 

18. ·Covered_________________________________ 32 180 
STRATIGRAPmC SECTIONS OF THE MARTIN FORMATION 129 

SECTION 18.-Two miles sottth of Turkel! Peak-Continued 

:VIartin Formation-Continued ~;:i~- ~~~~; 

Jerome Member-Continued thick- thickUpper unit-Continued t};~:,) /.f~~h 

17. Dolomite, pale-red (lOR 6/2), saccharoidal ; lower part of unit consists of dolomite crystals which fall into tvvo clearly 

distinct size groups : ( 1) idiom orphic and 

hypidiomorphic crystals 0.5-1.0 nun in diameter and (2) clusters of idiomorphic 

and hypidiomorphic crystals about 0.07-

0.1 mm in diameter; upper part of subunit is uniformly fine crystalline and contains a considerable admixture of very 

fine sand. Medium-bedded (beds are 1 

ft thick). (H56-148, 147) -------------- 15 148 

16. Sandstone grayish-pink ( 5R 8/2) ; contains 

much dolomitic finely crystalline matrix; 

quartz grains poorly sorted and range in 

size from silt to about 0.7 mm in diameter ; larger grains generally well rounded 

to subrounded and etched around margin; crops out as one resistant bed. 

(H56-146)____________________________ 2 133 

15. Dolomite grayish-pink saccharoidal very 

sandy; contains quartz grains as much as 

1 mm in diameter; laminated; has a 

few vugs as wide as 7 nun filled with 

coarse-crystalline calcitic dolomite______ 5 131 

14. Dolomite grayish-pink (5R 8/2) finely crystalline; contains pockets and layers of 

mostly fine grained detrital quartz ; contains some larger grains, which are subrounded and as much as 0.5 mm in diameter; crops out as one bed; weathers yellowish gray. (H56-145) -------------- 5 126 

13. Dolomite, grayish-pink ( 5R 8/2), very fine 

grained, hard, resistant, medium-bedded 

(beds are 11-h ft thick) ; weathers yellowish gray. (H56-144) --------------- 10 121 

12. Covered________________________________ 5 111 

11. Sandstone, pinkish-gray (5YR 8/1) ; contains much matrix composed of calcitic 

dolomite; beds are poorly sorted ; grains 

range in size from silt to 1 mm in diameter ; larger grains are generally subrounded, and most have highly etched 

surfaces; laminated; weathers grayish 

orange pink. (H56-143)______________ 1 106 

10. Covered________________________________ 2 105 

9. Dolomite, similar to subunit 7------------ 3 103 

8. Covered_________________________________ 4 100 

7. Dolomite, light-gray (N 7), very finely to 

finely crystalline; contains some detrital 

quartz, mostly silt, and very few subangular larger gmins as large as 0.2 mm ; 

crops out a.s three resistant beds; 

weathers light gray (H56-142) ________ 4 96 

6. Dolomite, light-gray, finely crystalline, 

silty; poorly exposed__________________ 17 92 

SECTION 18.-Two miles south of Turkel! Peak-Continued 

Martin Formation-Oontinued 

.Jerome Member-Continued 

Upper unit-Continued 

Sub- Oumuunit lative 

thick- thick- ness ness (feet) (feet) 

fl. Dolomite, mottled light brownish-gray 

( 5YR 6/1) and brownish-gray ( 5YR 4/1), 

finely crystalline, saccharoidal; contains 

a small amount of detrital quartz grains 

as much as 0.3 mm in diameter ; has a few 

calcite vugs, as much 1 em in diameter ; 

contains some gray chert nodules as much 

as 1.5 em in diameter; weathers light 

olive gray. ( H56-141) ---------------- 1 75 

4. Dolomite, pale-red, saccharoidaL_________ 1 74 

3. Dolomite breccia, medium-gray; composed 

of angular dolomite fragments; thinbedded; poorly exposed ________________ 12 73 

2. Dolomite, grayish-pink (5R 8/2), pale-red 

(5R 6/2), and light brownish-gray (5YR 

6/1) ; lower half, medium to coarse crystalline, beromes fine crystalline in upper 

part; basal 5 ft, very sandy, containing 

detrital quartz grains as much as 0.5 mm 

in diameter, generally subrounded ; many 

grains are shattered; medium-bedded 

(beds are 1ft thick) weathers brownishgray ( H56-140, 139, 138, 137) --------- 37 61 

Aphanitic dolomite unit: 

1. Dolomite, grayish-pink (5R 8/2) to pale-red 

( 5R 6/2) ; very finely crystalline ; rich in 

detrital quartz grains, which diminish in 

size from bottom to top of the subunit; 

bottom layer, 1-2 ft thick, contains wellrounded quartz grains as much as 1 mm 

in diameter ; smaller grains generally 

subangular; this layer also contains angular to subrounded pebbles of underlying rock as large as several centimeters 

in diameter; the dolomitic matrix is microbreccial; upper part of unit contains 

calcite veinlets and vugs as much as 1 em 

in diameter. Medium-bedded (beds are 

about 2 ft thick) ; weathers grayishorange-pink. (H56-136, 135; T56-538) __ 24 24 

Precambrian: Mazatzal ( ?) Quartzite. Fine-grained 

quartzite and chert. ( H56-134 )'. 

SECTION 19.-ChJ·i.<~topher Mountain Ridge 

[Gila County (Tonto National Forest, NW~ sec. 12, T. 10% N., R. 13 

EJ. unsurveyed). Photograph lots AK 3123. Measured by Curt Teichert, 195'6] 

Martin Formation: Sub- Oumuunit lative 

Jerome Member : thick- thickUpper unit: t};;:) t};;:) 

18. Dolomite, calcitic ; CaCOa content varies 

greatly; motled in varying shades of pale 

red (5R 6/2), fine- to medium-grained; 

upper 2 ft finer grained and sandy, containing layers of detrital quartz grains 

ranging in size from silt to about 1 mm 

in diameter, poorly sorted; large grains 

subrounded to well rounded; mediumbedded ; weathers pale red. ( T56-460, 

459)---------------------------------- 12 144 
130 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 19.-0hristopher M otmtain Ridge-Continued 

Martin Formation-Continued 

.Jerome Member-Continued 

Sub- Oumuunit lative 

thick- thickUpper unit-Continued <i:!f) (;:~~) 

17. Covered interval________________________ 8 132 

16. Dolomite, slightly calcitic, pale-red (5R 

6/2), fine- to medium-grained; contains 

pebbles of very fine grained slightly 

darker red dolomite; contains completely 

recrystallized Amphipora skeletons; thick 

bedded; weathers pale red. (T56-458) __ 9 124 

1:l. Limestone, light-gray (N 7) ; dense-calcilutite; contains sparsely scattered siltsized detrital quartz, nowhere composing 

more than 1 percent of the rock; lower 

6 in. contains abundant brachiopod and 

gastropod fragments and calcispheres; 

medium-bedded; weathers light gray. 

('T56-457) --------------------------- 3 115 

14. Dolomite, pale-red, medium-grained, saccharoidal, soft; poorly exposed ________ _ 

lR Dolomite, calcitic, mottled pinkish-gray 

(5YR 8/1) and grayish-pink (5R 8/2), 

fine- to medium-grained ; contains large 

(as much as 1 ft) colonies of fossils, 

which are completely recrystallized and 

no trace of detailed skeletal structures is 

preserved; thick-bedded; weathers light 

gray to yellowish gray. (T56-456) ___ _ 

12. Dolomite, light brownish-gray (5YR 6/1) ; 

medium-grained, saccharoidal, the bulk 

of rock is an aggregate of hypidiomorphic dolomite crystals about 0.5 mm. 

in diameter; between the crystals is a 

"matrix" of small idiomorphic dolomite 

crystals about 0.05 mm. ; many angular 

silt-sized quartz fragments occur throughout, most of which are embedded in the 

l·arge dolomite crystals ; also, larger 

detrital quartz grains as much as 1 mm. 

in diameter, many of which are somewhat corroded and replaced by dolomite. 

Thick..Jbedded; weathers pale red. ( T56-

455) --------------------------------- 11. Covered; probably thin-bedded dolomite __ 

10. Dolomite, slightly calcitic, irregularly mottled pinkish-gray (5YR 8/1) ·and pale-red 

(5R 6/2) ; very fine grained; contains a 

negligible quantity of silt-sized detrital 

quartz; thick-bedded, massive; weathers 

light gray. ( T56-454) -----------------

9. Dolomite, ·slightly calcitic, mottled grayishpink (5R 8/2) and pale-red (5R 6/2), 

very fine grained; rich in detrital quartz 

particles of silt size, which make up as 

much as 10 percent of rock ; has irregularly laminated appearance due to alter3 112 

3 109 

5 106 

7 101 

4 94 

SECTION 19.-0hristopher Mountain Ridge-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

Sub- Oumuunit lative 

thick- thick- ness ness (feet) (feet) 

9. Dolomite, etc.-Continued 

nation of pink and pale-red color that is 

not caused by mineralogical changes ; 

thin- to medium-bedded; poorly exposed; 

weathers pale red. (T56-453) --------- 16 

8. Dolomite, slightly calcitic, very light gray 

(N 8) ; fine- to medium-grained, saccharoidal ; composed mostly of hypidiomorphic crystals averaging 0.2-0.3 mm. 

in diameter; thick-bedded (beds are 11h 

ft thick) ; weathers light gray. (T56-

452) --------------------------------- 7. Covered interval _______________________ _ 

6. Dolomite, slightly calcitic, mottled light 

brownish-gray (5YR 6/1) ·and pale-red 

( 5R 6/2), very fine grained ; contains 

scattered vugs as much as llh inches in 

diameter, filled with clear calcite and 

dolomite; medium- to thick-bedded; 

weathers medium light gray. (T56-

451) --------------------------------- 5. Dolomite, light brownish-gray (5YR 

6/1), very fine grained; contains scattered silicified fragments of stromatoporoids and T'hamnopora; fossils 

very unevenly distributed along 

strike; thick-bedded; weathers yel3 

7 

8 

90 

74 

71 

64 

lowish brown. (T56-450) ----------- 5 56 

4. Dolomite, mottled yellowish-gray (5YR 

8/1) and pale-red ( 5R 6/2) , :finegraiood, stylolitic, thick-bedded 

(beds are about 2ft thick) ; weathers 

medium gray. T'his subunit is poorly 

exposed and includes some more uniformly light gray as well as more uniformly pale-red beds of same texture. 

(T56-449) ------------------------ 21 51 

3. No outcrops ; slope covered with 

dolomite talus_____________________ 9 30 

2. Dolomite, slightly calcitic, medium 

light-gray (N 6), very :fine grained; 

contains numerous very small vugs 

:filled with pink to clear calcite and 

dolomite; in part saccharoid'al; thickbedded; weathers light gray. Outcrops poor in lower half, good in 

upper half. (T56-448) ------------- 13 21 

1. Sandstone, light-brown, mediumgrained; weathers dark brown. No 

outcrops, but loose slabs cover ground 

for a distance equivalent to an approximate thicknes~s of______________ 8 8 

Base not exposed. 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 131 

SECTION 20.--Hunter and Sharp Oreek8 

[Upstream from point near junction of Sharp Creek. On the map of 

Tonto National Forest the creek named Hunter Creek on the Promontory Butte quadrangle is called Sharp Creek. This, however, is the 

name of the tributary which flows into Hunter Creek from the north 

about 2 miles from the latter's junction wih Christopher Creek. 

(Tonto National Forest, NW%, sec. 32 T. 11 N., R. 13 E.). Photograph lots AK 3122, 3123. Measured by Curt Teichert, 1953; additional observations, 1957] 

Martin Formation: 

Jerome Member: 

Upper unit: 

22. Dolomite, pale-red (lOR 6/2) , very fine 

grained ; contains abundant detrital 

quartz grains as much as 0.5 mm in 

diameter, rounded to subrounded, and 

in places tightly packed; rich silicified 

coral fauna (Disphyllum? sp., Stringophyllum? sp). ( T-301, 300) --------

21. Dolomite, pale-red, :finely crystalline, 

Sub-

'Unit 

thickness 

(feet) 

9 

Oumulative 

thickness 

(feet) 

174 

hard, massive______________________ 1 165 

20. Dolomite, yellowish-gray, coarsely 

crystalline (similar to subunit 3) ____ 11 164 

19. Covered ----------------------------- 5 153 

18. Dolomite, pale-red, very :finely crystalline, thin bedded (beds are 4-6 in. 

thick) ---------------------------- 3 148 

17. Poor exposures; probably a continuation of subunit 16, but contains a certain amount of detrital quartz grains_ 22 145 

16. Dolomite, light-gray, fine- to mediumcrystalline; thick-bedded (beds are 

as much as 3% ft thick)------------ 15. 5 123 

15. Covered ; probably continuation of subunit 14---------------------------- 5.5 107.5 

14. Dolomite, very light gray (N 8), very 

:finely crystalline, argillaceous; contains scattered detrital quartz grains, 

rounded to subrounded and as much 

as 0.5 mm in diameter; thin-bedded 

(beds are 3-6 in. thick) ; weathers 

pinkish gray. (T299) -------------- 13. Covered _____________________________ _ 

12. Dolomite, light-gray, coarsely crystal8.5 102 

2 93.5 

line, thin-bedded (beds are 1-3 in. 

thick)_____________________________ 5.5 9L5 

11. Dolomite, light-gray ( N 7), very finely 

crystalline, argillaceous ; contains 

with spherical calcite vugs as much 

as 1 em in diameter ; thin-bedded ; 

weathers light olive gray. (T298)__ 3. 5 86 

10. Dolomite, light-gray, coarsely crystalline, thick-bedded; weathers gray___ 7. 5 82. 5 

9. Dolomite, pale-red (5R 6/2), very 

finely crystalline, thin-bedded (beds 

are 1-2 in. thick) ; weathers pale red. 

( T297) ----------------------------- 5 75 

8. Dolomite, light brownish-gray to palered, finely crystalline; contains scattered detrital quartz in a few layers; 

the quartz is more abundant in upper 

part; at top of subunit, the grains are 

5 mm in diameter ; generally thin- to 

medium-bedded; weathers pale red__ 27 70 

7. Covered______________________________ 3 43 

SECTION 20.-Hunter and Sharp Greeks-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

G. Dolomite, slightly calcitic, light brownish-gray (5YR 6/1), finely crystalline, 

massive; weathers light olive gray. 

( T296) -----------------------------

5. Dolomite, pale-red ; similar to subunit 3, 

but thinner bedded ________________ _ 

4. Sandstone, light brownish-gray (5YR 

6/1), poorly sorted, medium- to 

coarse-grained ; grains generally subrounded; medium-bedded (beds are 

6-15 in. thick) ; crossbedded; weathers medium gray. ( T295) ----------

3. Dolomite, calcitic, pale-red (lOR 6/2), 

medium-crystallime, argillaceous ; contains large white calcite veins as 

much as 1 em wide; thick-bedded 

(beds are 2-3 ft thick) ; weathers 

pale red. (T294) _________________ _ 

2. Sandstone, mottled pale-red and lightgray, medium-grained; several layers 

contain angular quartzite clasts as 

much as 10 in. in diameter; breccia 

bed on top of subunit; thick-bedded 

(beds are 2.-3 ft thick) , but thinner 

bedding (beds are 2-3 in. thick) is 

produced by weathering ____________ _ 

1. Sandstone, yellowish-gray, well-sorted, 

medium-grained; contains a basal 

breccia (6 in. thick) containing angular quartzite pebbles as much as 4 in. 

in diameter; weathers grayish red __ _ 

Precambrian: Mazatzal Quartzite; quartzite, 

grayish-red, fine-grained, thin-bedded. 

SECTION 21.-Hunter· Oreek 

Subunit 

thickness 

(feet) 

2 

5.5 

9 

16 

4 

3.5 

Oumulative 

thickness 

(feet) 

40 

38 

32.5 

23.5 

7.5 

3.5 

[0.6 mile east of junction of Hunter and Christopher Creeks (Promont()ry Butte quadrangle, W%SE%, sec. 30, T. 11 N., R. 13 E.). Photograph lots AK 3121, 3122. Measured by Curt Teichert, 1953 ; additional observations, 1957] 

Martin Formation: 

Jerome Member : 

Upper unit: 

17. Limestone, yellowish-gray (5Y 8/1), 

medium- to very coarsely crystalline, 

saccharoidal; contains less than 1 

percent detrital quartz, mostly silt 

sized, and scattered grains as much as 

1 mm in diameter; weathers brownish 

gray. (L-165) ----------------------

16. Limestone, pale red-purple (5RP ,6/2) 

with pale greenish-yellow (lOY 8/2) 

patches; very :finely crystalline; 

weathers medium light gray. (L164)-------------------------------

15. Limestone, pale-red (5R 6/2) with lightgray streaks, very :finely to :finely 

crystalline; contains less than 1 percent detrital quartz ranging in size 

from silt to very :fine; weathers pale 

red. (L-163)-----------------------

suounit 

thickCum-ulative 

thick- ness ness 

( jeet) (feet) 

5 117 

4.5 112 

4.5 107.5 
132 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 21.-Hunter Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

14. Dolomite, calcitic, grayish orange-pink 

( 5Y R 7/2), medium crystalline, saccharoidal ; contains interstitial calcite; weathers grayish orange pink. 

(L-162)---------------------------

13. Dolomite, calcitic, grayish-orange (10 

Y R 7/4), coarsely crystalline; contains much interstitial calcite; weathSub-

'llnit 

thickness 

(feet) 

2 

Cumulative 

thickness 

(feet) 

103 

ers medium light gray. ( Ll61) ______ 3. 5 101 

12. Covered ; underlain by dolomite or limestone ______________________________ 11.5 97.5 

11. Limestone, highly dolomitic, pale reddish-brown (lOR 5/4) to pale-orange 

(lOY R 8/2) ; intimate mixture of 

medium crystalline calcite and dolomite; contains as much as 3 percent detrital quartz, ranging in size 

from silt to 0.7 mm in diameter; 

weathers light brown. (Ll60, 159)___ 8 86 

10. Sandstone, pale-red (lOR 6/2), poorly 

sorted ; contains subrounded grains 

as much as 0.8 mm in diameter; contains much carbonate matrix consisting of calcitic dolomite. (Ll58) ___ 4 

9. Covered; probably underlain by sandstone______________________________ 13 

8. Sandstone, very pale orange (lOYR 

8/2) to grayish orange-pink (5YR 

7/2), poorly sorted ; contains grains 

reaching a maximum of about 1 mm 

in diameter; the grains that are 

larger than about 0.2 mm are generally rounded to subrounded ; contains a considerable amount (as much 

as 50 percent) of carbonate matrix 

consisting of coarsely to very coarsely 

crystalline dolomite and much interstitial calcite; weathers light brown. 

78 

74 

(T56-464--Ll57)------------------- 4 61 

7. Dolomite, calcitic, mottled pale red and 

light-gray, saccharoidal; contains 

some scattered detrital quartz grains 

as much as 4 mm in diameter_______ 11. 5 57 

6. Covered; probably underlain by dolomite _______________________________ 10.5 45.5 

5. Dolomite, calcitic, grayish orange-pink 

(5YR 7/2), very coarsely crystalline, 

saccharoidal, thin-bedded; weathers 

medium light gray and light brown__ 10. 5 35 

4. Dolomite, grayish orange-pink (5YR 

7/2) , finely crystalline ; contains 

scattered detrital quartz grains, subangular, as much as 1.5 mm in diameter ; contains a few vugs filled 

with brown calcite; thin-bedded ; 

weathers pale brown_______________ 6 24. 5 

SECTION 21.-Huntm· Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

3. Covered; probably sandstone ________ _ 

2. Dolomite, calcitic, grayish orange-pink 

(5YR 7/2), coarsely to very coarsely 

crystalline, saccharoidal ; contains 

much interstitial calcite between dolomite crystals ; composed of idiomorphic dolomite crystals subrounded by 

calcite linings; contains very little 

(less than 1 percent) detrital fine 

Subunit 

thickness 

(feet) 

4.5 

Cumulative 

thickness 

(feet) 

18.5 

quartz grains______________________ 2 14 

1. Sandstone and conglomerate, pinkishgray ; sandstone generally medium 

grained, composed of subangular 

grains and considerable overgrowth ; 

poorly exposed_____________________ 12 12 

Unconformity. 

Cambrian(?) : Sandstone, moderate orange-pink, poorly sorted, 

medium-grained. 

SECTION 22.-Four-tenths mile west of Christopher Ranch 

[Promont(}ry Butte quadrangle, about center of NW1J1 sec. 30 T. 11 

N., R. 13 E. Photograph lots AK 3121, 3122. Measured by Curt 

Teichert, 1953 and 1957] 

Martin Formation: Sub- OumuJerome Member: /i~~t :~~~~~ 

Upper unit: /J:!Z) ti~:~) 

9. Sandstone, calcareous, grayish-orange ( 10 

YR 7/4), poorly sorted, medium- to 

coarse-grained ; larger grains, rounded 

to subrounded, etched; contains much 

calcareous cement; very poorly exposed. 

(T57-383, 382) ------------------------- 5 110 

8. Dolomite, calcite, grayish-orange (lOYR 

7/4), coarsely crystalline; contains interstitial calcite; contains a considerable amount of detrital quartz increasing in amount from bottom to top of the 

subunit ; the uppermost 6 ft is composed 

of as much as 20 percent quartz grains, 

which are as much as 0.5 mm in diameter 

and poorly sorted ; larger grains, 

rounded; also contains many small 

rounded pebbles of Mazatzal Quartzite; 

medium-bedded ; very poorly exposed; 

weathers light brown. (T57-381; T293) _ 40 105 

7. Sandstone, poor outcrops_________________ 6 65 

6. S'andstone, gl'layish orange-pink (lOYR 

8/2), poorly sol'lted, medium- to coarsegrained ; con:tJairus lenses of fine-grained 

quiartz ~and scattered granules of quartz 

more than 2 nun in diameter ; <tightly 

packed within ma'trix; large grains, 

subrounded to rounded; medium-'bedded; 

fr•rable; weather'S light gray. (T57--380; 

T292?) --------------------------------- 12 59 

5. Covered__________________________________ 11 47 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 133 

SECTION 22.-Fout·-tenths mile west of Christopher Ranch-Con. 

Martin Formation-Continued Sub- Oumuunit lative 

Jerome Member-Continued thick- thickUpper unit-Continued <i!!~) (j:~~) 

4. Dolomite, oolcitic, grayish-orange (10YR 

7/4), eoafiSely crystalline, s:accharoidal ; 

contains in·ters:titial oakHe ; contains 

much detri'tal quartz grains (as much 

as 20 percent) , which are subangular to 

rounded and 'as much 'a's 1 mm in diameter; medium-bedded (beds are 8-12 

in. thick) ; friable; weathers pale yellowish-brown. ( T57-379; T290) ___________ 6 36 

3. Covered__________________________________ 8 30 

2. Dolomite, very pale orange (10YR 8/2), 

coarsely to very coarsely crysltalline ; 

contains a very small amount of silt 

(less than 1 percent) ; thick-bedded; 

weathers grayish orange pink. T57-

378; T291 ?) --------------------------- 6 22 

1. Sandstone, pale-red (5R 6/2), laminated 

medium and coarse grained; contains 

quartz gr'aillls, angul,ar to 'suball'gular, and 

u scattering of 1arge rounded quartz 

gmnules as much as 3 mm. in diameter; 

conglomeratic layer, 2 1Jt thick, at base; 

thlck-bedded (beds are 1-3 ft thick) ; 

slightly crossbedded; weathers pale purple ----------------------------------- 16 16 

Angul!a:r unconformity. (T57-377, 376.) 

Precambdan: MuZiatz:al Quartzi,te. 

SECTION 23.-Christopher Creek 

[Small canyon 0.4 mile east of Christopher Creek Camping Area (Promontory Butte quadrangle, on border of NEJ4 sec. 25 T. 11 N., R 12 E., 

and NWJ4 sec. 30, T. 11 N., R. 13 E.). Photograph lots AK 3121, 

3122. Measured by Curt Teichert, 1953] 

Martin Formation : 

J ei"ome Member : 

Upper unit: 

2. No well-defined outcrops, but 

ground strewn with irregut<arly weathering slabs of brown 

fine- to medium-groined slandSubunit 

thickness 

(feet) 

Gltmulative 

thickness 

(feet) 

stone________________________ about 30 about 100 

1. Oovered ; lithology unknown____ a:bout 70 'about 70 

Precambrian: Mazatzal(?) Quartzite; grayish-red, very fine 

gi"ained ; in part schistose. 

SECTION 24.-Christopher Creek Campmg Area 

(Promontory Butte quadrangle, just south of center NE:!4 sec. 25, 

T. 11 N., R. 12. E. Photograph lots AK 3121, 3122. Measured by 

Curt Teichert, 1953] 

Martin Formation: 

Jerome Member: 

Upper(?) unit: 

1. Sandstone, medium dark-gray (N 4), 

poorly sorted; grains range in size 

from silt to about 1 mm in diameter; 

most grains 0.1 mm and larger are 

rounded to subrounded ; also, some 

small flat pebbles of underlying quartzite as much as 2 em in diameter are 

SECTION 24.-Christopher Creek Camping Area-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

1. Sandstone, etc.-Continued 

scattered through subunit; thin-bedded; 

weathers brownish gray and yellowish 

gray ________________________________ _ 

Precambrian: Mazatzal(?) Quartzite; quartzite, 

grayish-red, thick-bedded. 

SECTION 25.-Boy Scout Ranch No.1 

Sub- Oumuunit lative 

thick- thickness ness (feet) (feet) 

0-15 0-15 

[North bank of Christopher Creek, near stables (Promontory Butte 

quadrangle, N72SE14 sec. 26, T. 11 N., R. 12 E.). Photograph lots 

AK 3121, 3122. Measured by Curt Teichert, 1953] 

Martin Formation: 

Jerome Member: 

Upper unit: 

7. Sandstone and conglomerate, medium 

light-gray, mottled pale-red and olivegray; calcareous matrix; poorly 

sorted ; smaller quartz grains-0. 7 

mm and less-rounded to subrounded ; 

larger pebbles of quartz and quartzites 

are as much as 1 em in diameter and 

are angular to subangular; weathers 

Sub- Gumuunit lative 

thick- thick- ness ness 

(feet) (feet) 

medium gray------------------------ 5 39+ 

6. Dolomite, slightly calcitic, lightgray (N 7) to medium light-gray 

( N 6) , finely crystalline ; weathers 

medium light gray to light brownish 

gray. (L-189)______________________ 1 34+ 

5. Covered; probably underlain by dolomite_________________________________ 3 33+ 

4. Dolomite, calcitic, grayish orange-pink 

(5YR 7/2), coarsely crystalline, thickbedded; weathers light brown. (Ir188, 187)---------------------------- 6 30+ 

3. Covered; probably underlain by sandstone--------------·------------------ 6 24+ 

2. Sandstone, yellowish-gray, calcareous, 

thin-bedded, poorly exposed___________ 2 18+ 

1. Sandstone, mottled pale-brown and yellowish-gray, medium-grained, thickbedded, poorly exposed-------------- 16+ 16+ 

Base of Devonian not exposed ; thickness of missing section unknown. 

Precambrian: Mazatzal Quartzite; quartzite, 

grayish-red, thick-bedded. 

SECTION 26.-Doubtjul G-reek 

[1.2 miles east orf Kohl Ranch, in canyon below road (Promontory Butte 

quadrangle, south of center sec. 22, T. 11 N., R. 12 E.). Photograph 

lots AK 3120, 3121. Measured by R. L. Harbour, 1956] 

Martin Formation: 

Jerome Member : 

Upper unit: 

17. Limestone, yellowish-gray (5Y 7/2) to 

grayish-orange (10YR 7/4) ; very 

sandy, contains 46 percent poorly 

sorted detrital quartz ; grains range 

in size from silt to 0.5 mm in 

diameter ; larger grains, subrounded ; some of the larger grains 
134 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 26.-Doubtful Greek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

17. Limestone, etc.-Continued 

Sub-

~mit 

thickness 

(feet) 

have a narrow peripheral shattered 

zone; in upper part of subunit, most 

grains are more badly shattered; 

limestone matrix, fine grained to 

medium grained; lower part of subunit grades into sandstone; thickbedded; cliff-forming, as three massive beds. (H56-165, 166) --------- 10 

16. Dolomite, grayish orange-pink (5YR 

7/2), subaphanitic; contains much 

detrital quartz ranging in size from 

silt to 1 mm in diameter ; large 

grains, rounded and etched ; all 

quartz grains, badly shattered. 

(H56-167) ----------------------- 15. Sandstone, light-gray, very dolomitic ; 

lower half contains much calcareous 

matrix; upper half contains angular 

fragments of chert and dolomite, and 

rounded quartzite pebbles as much 

2 

as 12 mm in diameter ; contains 

poorly preserved brachiopod fragments (spiriferids?) ; two beds_____ 2 

14. Dolomite, grayish-orange (lOYR 7/4), 

very fine grained ; contains as much 

as 30 percent detrital quartz, poorly 

sorted, ranging in size from silt 

to 1.5 mm ; larger grains, rounded 

to subrounded and have slight marginal etching ; one easily weathered 

bed; weathers pale brown. (H56-

168) ----------------------------- 3 

13. Sandstone, pale-red (lOR 6/2), poorly 

sorted, fine- to coarse-grained; contains much fine-grained calcareous 

cement; larger quartz grains tend 

to occur in small clusters and 

slightly interlocked ; lowermost foot, 

argillaceous; remainder of subunit, 

one bed. (H56-169) --------------- 11 

12. Dolomite, grayish orange-pink (5YR 

6/4), very finely crystalline to 

subaphanitic ; contains varying 

amounts of silt and very fine grained 

sand, the amount increasing! to 

about 10 percent in upper part of 

subunit, which also contains Spinatrypa cf. S. rotunda Stainbrook; 

upper 5 ft contains coarse quartz 

pebbles ; bedding variable from thin 

to thick ( 6 in. to 6 ft) ; weathers 

lightbrown. (LP-136; H56-170) ___ 24 

11. Dolomite, light-gray, finely crystalline; 

fissile, containing clay partings; at 

base, about 3 in. of coarse to fine 

sandstone occurs, which forms niche 

below prominent cliff______________ 4 

Cumulative 

thickness 

(feet) 

175 

165 

163 

161 

158 

147 

123 

SECTION 26.-Doubtful Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

10. Dolomite, light-gray (N 7), very finely 

to finely crystalline ; contains as 

much as about 3 percent detrital 

quartz, very poorly sorted, ranging 

in size from silt to about 1 mm in 

diameter ; grains have varying degrees of roundness ; thin-bedded ; 

weathers light olive gray. (H56-

Subunit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

172)------------------------------ 12 119 

9. Dolomite, light-gray (N 7), very finely 

to finely crystalline, hard; detrital 

matter mostly silt size and smaller; 

contains a few subangular quartz 

grains as much as 0.3 mm in diameter; medium-bedded (beds are 1 ft 

thick) ; weathers light gray. (H56-

173)------------------------------ 10 107 

8. Dolomite, grayish-pink, very fine 

grained, argillaceous ; fills channels 

in underlying subunit 7------------ 0-4 97 

7. Dolomite, pinkish-gray (5YR 8/1) and 

grayish-pink ( 5R 8/2) ; light olive 

gray (5 Y 6/1) in upper part·; very 

finely crystalline ; contains a small 

amount of silt-sized to very fine 

grained detrital quartz; thin-bedded (beds are 4 in. thick) ; basal 

layers contain small lenses of redtinted clay. (H56-180-181, 182) --- 41-45 93-9'i 

6. Dolomite, mottled grayish-pink (5R 

8/2) and grayish orange-pink lOR 

8/2), very finely crystalline; lower 

2-3 ft, very sandy ; detrital material 

consists of poorly sorted subangular 

to angular quartz grains as much 

as 1 mm in diameter and of chert 

fragments ~s much as 2 mm in diameter; also contains dolomite clasts 

as much as 12 em in diameter; higher up, the subunit becomes finely to 

very finely crystalline, 1and the detrital component is very fine grained to 

silt size; poorly bedded and resistant. (H56-183, 184) -------------- 18 52 

5. Dolomite, pale-red (5R 6/2), coarsely 

crystalline; about 1 percent detrital 

quartz is silt size and very fine 

grain size ; contains a few large subrounded grains as much as 0.3 mm in 

in diameter ; more sandy near bottom of subunit ; basal 3 ft contains 

angular dolomite clasts ; poorly bedded and resistant; weathers brownish gray. (H186-185) ------------ 15 34 

4. Claystone, pale-red, and saccharoidal 

dolomite containing angular fragments of dolomite; poorly exposed__ 3 19 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 

SECTION 26.-DoubtfuZ Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

3. Dolomite, mottled grayish-pink ( 5R 

8/2), pale-red (5R 6/2), and pinkishgray (5YR 8-1) ; coarsely crystalline, saccharoidal; contains about 

1 percent very fine detrital quartz; 

angular dolomite pebbles occur at 

base of subunit; rests in places directly on Precambrian rocks; cliffforming. (II56-186) _____________ _ 

2. Conglomerate, pale-red (5R 6/2) ; composed mainly of angular to subangular dolomite pebbles as much as 2 

em in diameter embedded in a clayey, 

silty, and sandy matrix that also 

contains some small pebbles derived 

from the Precambrian fills channels 

beneath subunit 3 and locally cuts 

out underlying subunit 1 along el'osional unconformity. (II56-187) __ _ 

1. Dolomite, pale red-purple ( 5RP 6/2; 

contains some red- and green-tinted 

mottling; medium crystalline; contains about 1-2 percent evenly distributed _detrital quartz, mostly silt 

size to very fine grain size, and a few 

rounded grains as much as 0.4 mm 

in diameter; poorly bedded. (II56-

Subunit 

thickness 

(feet) 

8 

0-3 

Oumulative 

thickness 

(feet) 

16 

8 

188) ----------------------------- 8-0 0-8 

Precambrian : volcanic rocks. 

SECTION 27.-Tonto and Horton Creeks 

[Ridge between Tonto and Horton Creeks near their junction, 1-1.3 

miles north of Kohl Ranch (Promontory Butte quadrangle, NW1,4 

sec. 16, T. 11 N .• R. 12 E.). Photograph lots AK 3120, 3121. Measured by Curt Teichert, 1953 and 1956] 

Martin Formation : 

Jerome Member : 

Upper unit: 

20. Limestone, dolomitic, paler-red (lOR 

6/2), very fine grained; laminated 

by zones of idiomorphic dolomite 

crystals that are as much as 0.15 

mm in diameter ; thin-bedded; poorly 

exposed; weathers yell-owish gray. 

(T57-372, 370) --------------------

19. Limestone, dolomitic, mottled pale reddish-brown (lOR 5/4) and grayishorange (lOYR 7/4), medium crystalline, argillaceous, medium-bedded, 

richly fossiliferous; contains abundant silicified colonies of Disphyllum 

spp., Hexagonaria sp., and "Aulopora" spp. ; weathers pale red. 

( T57 -371, 369, LP 75) -------------

Subunit 

thickness 

(feet) 

12 

13 

Oumulative 

thickness 

(feet) 

321 

309 

SEcTION 21.-Tonto and Horton Creeks-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

18. Sandstone, pinkish-gray (5YR 8/1) 

to yellowish-gray (5Y 8/1) ; not further subdivided; this unit contains 

very fine grained to coarse-grained 

rocks ; bedding ranges from thin to 

thick ; in coarse-grained parts ; the 

larger grains are rounded to subrounded; contains varying amount of 

dolomitic matrix that is locally 

slightly calcitic; weathers generally medium light gray to light 

brown. (T57-368, 367, 366) _____ _ 

17. Dolomite, medium light-gray (N 6), 

finely crystalline; contains numerous 

large and small calcite vugs as much 

as 35 mm in diameter ; no detrital 

quartz; lower two-thirds, irregularly platy to thick-bedded; upper 

third, thin-bedded (beds are 6-10 in. 

thick) ; weathers light olive gray. 

(T57-365) ----------·--------------

16. Dolomite, calcitic, yellowish-gray 

( 5Y 8/1) , coarsely crystalline, saccharoidal ; contains much interstitial calcite between dolomite 

crystals; thick--bedded (beds are 

2-3 ft thick) ; cliff-forming; weathers medium light gray. (L67; 

T57-364) -----------··--------------

15. Dolomite, light-gray (N 7), finely crystalline; evenly scattered silt-sized 

quartz particles make up 2-3 percent 

of rock ; very finely laminated by 

thin laminae composed of argillaceous matter; thin-bedded; poorly 

exposed; weathers light gray. (T57-

363) ----------------·--------------

14. Dolomite, light 'brownish-gray (5YR 

6/1), very finely to medium-crystalline ; contains almost no detrital 

quartz; irregularly thin-bedded; 

weathers light brown. (T57-362) __ 

13. Dolomite, light-gray ( N 8), finely crystalline; finely laminated by scattered layers of more concentrated 

argillaceous matter and silt; 

contains scattered very fine quartz 

grains and a few subrounded grains 

as much as 0.3 mm in diameter; 

thin-bedded ; weathers light olive 

gray. ( T57-361) ------------------

12. Dolomite, pale-red ( 5R 6/2), finely 

crystalline, saccharoidal, lowermost 

1-2 feet sandy; thinJbedded; poorly 

exposed ; weathers pale yellowish brown. (T57-360) _______________ _ 

Sub-

•unit 

thickness 

(feet) 

75 

16 

20 

15 

17 

30 

18 

135 

OumuZative 

thickness 

(feet) 

296 

221 

205 

185 

170 

153 

123 
136 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 27.-Tonto and HoTton 0Teeks-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

l'pper unit-Continued 

11. Sandstone, pale-red (lOR 6/2), coarsegrained ; grains rounded to subrounded; maximum of 30 percent calcareous ground mass ; thick-bedded ; 

cliff-forming; weathers pale red 

( T57-359) ----------·--------------

10. Dolomite, pale-red ( 5R 6/2), very finely 

crystalline; contains about 2 percent 

scattered detrital quartz; grains are 

as much as 0.5 mm in diameter ; 

larger grains, rounded to subrounded. 

(T57-358) ----·-------------------

9. Covered ; probably underlain by sandstone. (T57-357) ________________ _ 

8. Sandstone, grayish orange-pink ( 5R 

8/2) to pale-red (5R 6/2) ; contains 

poorly sorted subangular to rounded 

quartz grains as much as 2 mm in 

diameter ; contains varying amounts 

(maximum, 40 percent) of dolomitic 

very finely crystalline matrix ; has a 

few specimens of Umbella sp.; mecHum-bedded (beds are 6-12 in. 

thick) ; indistinctly crossbedded; 

weathers brownish gray. (T57-

356)------------------------------

7. Dolomite, pale-red (5R 6/2), mediumcrystalline; contains varying 

amounts (maximum, 50 percent) of 

detrital quartz grains, ranging in 

size mostly from silt to very fine; 

contain a few rounded to subrounded 

large grains as much as 1 mm in 

diameter; some grains have etched 

surfaces and overgrowth ; mediumbedded; weathers light brown _____ _ 

6. Dolomite, pale-red (5R 6/2), aphanitic; conchoidal fracture; contains 

layers of angular to subangular dolomite clasts as much as 0.5 mm in 

diameter; contains scattered detrital 

quartz, angular to subrounded, as 

much as 0.4 mm in diameter; medium-bedded (beds are 6-18 in. 

thick) ; weathers grayish orange 

pink. (T57-354) -----------------

5. Dolomite, mottled grayish-pink ( 5R 

8/2) and pale-red (5R 6/2), mediumto coarsely crystalline ; 

scattered poorly sorted 

contains 

detrital 

quartz grains, angular to rounded 

and as much as 0.5 mm in diameter ; 

contains small scattered patches; of 

authigenic chert; thick-bedded; 

weathers light brownish gray. 

( T57-353) -------------·-----------

Sub-

'llnit 

thickness 

(feet) 

17 

1 

16 

5 

11 

9 

6 

Oumulatit•e 

thickness 

(feet) 

105 

88 

87 

71 

66 

55 

46 

SECTION 27.-Tonto and Horton Creeks-Continued 

Martin Formation-Con tin ned 

Jerome Member-Continued 

Upper unit-Continued 

4. Conglomerate, containing boulders as 

much as 3 feet in diameter ; mostly 

quartzite and some dolomite pebbles 

and boulders ; lower surface channels into underlying subunit_ ______ _ 

3. Graywacke, dolomitic, contains conglomeratic bands; grayish-orange 

(10YR 7/4) ; contains angular to 

subangular poorly sorted chert and 

quartz fragments embedded in up to 

50 percent dolomitic groundmass; 

medium- to thick-bedded; poorly exposed; weathers light brown. (T57- 551) _____________________________ _ 

2. Covered; almost certainly underlain by 

sandstone similar to subunit 3 ____ _ 

1. Covered ---------------------------

Precambrian: Weathered igneous rock. 

SECTION 28.-Kohl Ranch 

Sub-

•unit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

9-15 40 

10-16 25-31 

10 15 

5 5 

[East bank of Tonto Creek, 0. 7-0.5 mile southeast of Kohl Ranch 

(Promontory Butte quadrangle, SEJ,4 sec. 21, T. 11 N., R. 12 E.). 

Photograph lots AK 3120, 3121. Measured by R. L. Harbour, 1956] 

Martin Formation: 

Jerome Member: 

Upper unit : 

S'll'b- Oumuunit lative 

thick- thickness ness (feet) (feet) 

32. Limestone, light-gray, argillaceous to 

sandy, medium-bedded; contains ?Tabulophyllum sp., A.trypa clarkei Warren, 

Spinat1·ypa cf. S. 1·otunda Stainbrook 

'!Platyracllella sp., spiriferid (genus 

indet.) -------------------------------- 17 292 

31. Dolomite, grayish orange-pink ( 5YR 7 /2), 

very finely crystalline; crops out as two 

beds. (H56-179) ---------------------- 1 275 

30. Covered, probably underlain by pale-red to 

light-brown medium-crystalline limestone or dolomite______________________ 18 274 

29. Dolomite, grayish-pink, saccharoidal; one 

bed___________________________________ 1 256 

28. Limestone, light-gray ( N 7), subaphanitic, 

clotty texture ; contains small amount of 

detrital quartz grains, very fine to silt 

size; laminated; platy, having ripple 

marks on bedding planes; weathers light 

brownish gray. (H56-178) ------------ 2 255 

27. Sandstone, pale-red (lOR 6/2). Similar to 

subunit 26, but dolomitic matrix is 

coarsely crystalline and contains interstitial calcite between dolomite crystals ; 

detrital component coarser in lower part. 

Grains are as much as 1 mm in diameter; 

upper part is free from detrital material, 

and the matrix is even more coarsely crystalline than lower part ; thin-bedded. 

(H56-177, 176)------------------------ 15 253 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 137 

SECTION 28.-Kohl Ranch-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

SECTION 28.-Kohl Ranch-Continued 

~~?i ~~1i~~ Martin Formation-Continued Sub- Cumuunit lative 

thick- thick- Jerome Member-Continued thick- thickUpper unit-Continued (j;;:,) t/~:~) 

26. Sandstone, moderate orange-pink ( 5:Y R 

8/4) to grayish orange-pink (5:YR 7/2); 

composed of about equal parts of detrital 

quartz and dolomitic matrix; detrital 

component poorly sorted, grains ranging 

in size from silt to 0.5 mm in diameter; 

larger grains, rounded to subrounded, 

surfaces etched ; overgrowths present on 

many of the larger grains; dolomitic matrix finely crystalline; thin-bedded; cliffforming; weathers medium dark gray. 

(II56-175) ____________________________ 10 238 

25. Dolomite, lightgray, subaphanitic; detrital 

quartz grains concentrated in parallel 

laminae_______________________________ 5 228 

24. Dolomite, grayish-pink, silty to sandy, 

poorly exposed_________________________ 5 223 

23. Dolomite, irregularly laminated very pale 

orange (10YR 8/2) and pinkish-gray 

( 5Y R 8/1), subaphanitic; contains abundant detrital quartz, which tends to be 

finer grained and more evenly distributed in the pale-orange bands and medium grained and more abundant in the 

pinkish-gray bands; quartz grains are 

poorly sorted and range in size from silt 

to about 0.5 mm in diameter; weathers 

light brown. (II56-174) --------------- 1 218 

22. Dolomite, yellowish-gray, finely crystalline; 

contains much detrital quartz___________ 3 217 

21. Covered _________________________________ 18 214 

20. Dolomite, grayish orange-pink (5YR 7/2) 

and fine pale-red ( 5R 6/2) mottling; very 

finely to finely crystalline; contains a 

scattering of detrital quartz grains as 

much as about 1 mm in diameter; all 

grains have etched surfaces-some grains 

possibly entirely changed to dolomitecontains some poorly preserved brachiopod fragments ; crops out as one bed ; 

slightly crossbedded; weathers pale yellowish brown. (II56-163) ------------- 3 196 

19. Covered_________________________________ 4 193 

18. Dolomite, light brownish-gray (5YR 6/1) 

and fine pale-red (5R 6/2) mottling, very 

finely to finely crystalline; contains a 

small amount (less than 1 percent) of 

silt-sized to very fine grained detrital material and scattered well-rounded larger 

quartz grains as much as 0.5 mm in 

diameter; contains poorly preserved silicified coral and brachiopod fragments; 

weathers light brownish gray. (II56-

162)---------------------------------- 10 189 

Upper unit-Continued (j;;:,) /.1~:~) 

17. Dolomite, light brownish-gray (5YR 6/2), 

coarsely crystalline, saccharoidal ; contains a few idiomorphic, mostly hypidiomorphic dolomite crystals and a very 

small amount (less than 1 percent) of 

silt-sized detrital quartz; medium-bedded 

(beds are 1 ft thick) ; weathers medium 

light gray----------------------------- 14 179 

16. Dolomite, light brownish-gray (5YR 6/2), 

very finely crystalline ; subconchoidal 

fracture; contains about 2-3 percent siltsized detrital quartz dispersed evenly 

throughout rock; thin-bedded; weathers 

grayish orange. (II56-169-159) _______ 27 165 

15. Dolomite, light brownish-gray ( 5Y R 6/1), 

very finely crystalline to subaphanitic; 

subconchoidal fracture; detrital material scarce ; grains are not larger than 

very fine sand size ; poorly exposed. 

(II56-158) ------------·---------------- 5 138 

14. Dolomite, grayish-pink ( 5R 8/2), finely to 

medium-crystalline. Lower part contains an abundance of detrital quartz 

grains, mostly medium to coarse, well 

rounded, and highly shattered; the 

amount of detrital quartz decreases upward and is not found in upper part of 

the subunit. Poorly bedded; weathers 

light brownish gray. II56-157-156) ____ 25 133 

13. Dolomite, grayish-pink ( 5R 8/2) ; subaphanitic; pelletal structure; contains 

calcite veinlets and vugs as much as 1.5 

mm wide; has abundant detrital quartz 

grains and some chert fragments; quartz 

grains, poorly sorted, are in all sizes to 

maximum of 1 mm in diameter ; almost 

all grains are highly shattered; almost 

all larger grains are covered by a thin 

rind of dolomite, probably resulting from 

etching of grains; larger grains, wellrounded to subrounded; crops out as one 

bed; weathers light olive gray. (II56-

155) --------------------------------- 4 108 

12. Sandstone, pale-red ( 5R 6/2) ; contains 

much matrix composed of calcitic dolomite ; very poorly sorted; quartz grains 

varying in size to a maximum of 1.5 mm 

in diameter ; larger grains, generally well 

rounded, many of them shattered; almost all show peripheral etching; contains an appreciable admixture of detrital chert fragments as much as 10 mm in 

diameter. (II56-154) ----------------- 4 104 
138 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SEOTION 28.-Kohl Ranch-Continued 

Martin Formation-Continued Sub-

'Unit 

Jerome Member-Continued thickUpper unit-Continued tJ:;:) 11. Covered _____________________________ 45 

10. Sandstone, grayish-red, coarse, conglomeratic; contains angular clasts 

as much as 12 mm in diameter; 

quartzitic at base _________________ _ 

9. Dolomite, mottled grayish-pink ( 5R 

8/2) and pale-red (5R 6/2), medium 

to coarsely crystalline ; contains 

varying amounts of detrital quartz, as 

much as 3 percent, poorly sorted, 

varying in size from silt to 0.5 mm 

in diameter; weathers grayish red. 

(II56-153)-------------------------

8. Conglomerate, grayish-red, soft; has an 

argillaceous matrix and contains 

angular quartz pebbles as much as 12 mm in diameter ________________ _ 

7. Dolomite, pale-red, saccharoidal; poorly exposed-------·------------------

6. Covered -----------------------------

5. Sandstone, grayish-pink ( 5R 8/2), 

coarse- to very coarse grained ; grains 

composed mostly of quartz and chert, 

poorly sorted ; also contains fragments of limestone and quartzite as 

much as 25 mm in diameter; thinbedded; weathers light brown. 

(II56-152)-------------------------

Aphanitic dolomite unit: 

4. Dolomite, pale-red (5R 6/2), very fine 

grained, argillaceous and silty ; contains a very few quartz grains as 

much as 0.2 mm in diameter; thinbedded; weathers grayish red. 

(II56-151)-------------------------

3. Sandstone, medium light-gray, very 

arkosic ; quartz grains are poorly 

sorted, rounded to subangular, as 

much as 3 mm in diameter _________ _ 

2. Sandstone, medium light-gray, arkosic, 

conglomeratic; has a slightly calcareous matrix; quartz grains are 

subangular, poorly sorted, range in 

size from 0.2 to 3.0 mm ; contains 

scattered pebbles as much as 6 mm 

in diameter; weathers dark gray ___ _ 

1. Sandstone, light-gray, medium-grained, 

somewhat arkosic; quartz grains 

subrounded to subangular, mostly 

between 0.2 and 0.4 mm in diameter ; 

contains scattered grains as much as 

2 mm in diameter------------------

Covered interval, in which the base of the Jerome 

Men1ber is situated _________________________ _ 

Precambrian: Granite. 

15 

1 

3 

2 

5 

14 

7 

3 

3 

2 

5 

Cumulative 

thickness 

(feet) 

100 

55 

40 

39 

36 

34 

29 

15 

8 

5 

2 

SECTION 29.-Thompson Wash 

[ 1.5 miles southwest of Kohl Ranch, north and south of highway bridge 

over Thompson Wash (Promontory Butte quadrangle,. sec. 29, T. 11 N., 

R. 12 E.). Photograph lots AK 3119, 3120. Measured by Curt 

Teichert, 1953 and 1957] 

Martin Formation 

Jerome Member : 

Upper unit: 

24. Limestone, ~olomitic, pinkish-gray (5 

YR 8/1), medium-crystalline; contains brachiopod remains (Atrypa?) 

and Thamnopora sp.; weathers me- dium gray. (IJ?214) _____________ _ 

23. Limestone, pale-red (5R 6/2), subaphanitic; subconchoidal fracture; argillaceous; very fossiliferous, containing Atrypa cf. A. devoniana Webster 

"Atrypa" owenensis Webster, Pla.tyrachella? sp., spiriferid (genus 

undet.); medium-bedded; weathers 

grayish pink. ( LP 213 ; T57 -398) ___ _ 

22. Dolomite, calcitic, grayish-pink ( 5R 

8/2), finely crystalline; contains 

much detrital quartz (as much as 

15 percent) ranging from very fine 

Sublunit 

thickness 

(feet) 

4 

7 

to silt in grain size; rich in brachiopods (spiriferids, Oranaena? sp.) ; 

thin-bedded, platy; weathers medium 

gray. (T57-397; LP 212) ---------- 14 

21. Chert, very light gray (N 8) to pinkishgray (5YR 8/1); composed almost 

wholly of silicified limestone ; consists 

of fine- to coarse-grained aggregate 

of hypidiomorphic to allotriomorphic 

crystalline quartz ; contains small 

patches of remnant finely crystalline, 

turgid calcite; all calcite patches have 

a habit like that of single crystals; 

highly fossiliferous, almost coquinalike, containing brachiopods, tabulate 

corals, and calcispheres( ?) ; thinbedded; weathers pale brown. (T57-

396)-------------------------------

20. Dolomite, calcitic, grayish-pink (5R 

8/2) to pale-red (5R 6/2), finely to 

medium crystalline, very sandy; contains detrital quartz grains of all 

sizes (maximum, 1 mm), generally 

rounded to subrounded; contains 

Thamnopora( ?) sp.; medium-bedded; 

weathers light brown. (LP 215; T57-

4 

395)------------------------------- 14 

19. Dolomite, calcitic, light-gray (N 7), 

very fine grained, very sandy ; contains poorly sorted detrital quartz 

making up as much as 50 percent of 

rock; grains are of all sizes (maximum, 1 mm in diameter); smaller 

grains, generally rounded to subrounded; contains Aulopora sp. and 

rugose corals; weathers light brown. 

(T57-393) ------------------------- 5 

Cumulative 

thickness 

(feet) 

282+ 

278+ 

271+ 

257+ 

253+ 

239+ 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 

SECTION 29.-Thompson Wash-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

18. Dolomite, slightly 

orange-pink (5YR 

calcitic, grayish 

7/2); medium- to 

coarse-crystalline ; contains interstitial calcite between hypidiomorphic dolomite crystals ; very s~andy ; 

contains detrital quartz grains ranging in size from silt to about 1 mm 

in diameter, and making up as much 

Subunit 

thickness 

(feet) 

as 50 percent of rock; contains gastropod fragments; weathers light 

brownish gray. (T57-394) --------- 2 

17. Covered _________________ ,_____________ 10 

16. Dolomite, slightly calcitic, pinkish-gray 

(5YR 8/1) and grayish-pink (5R 8/2) 

mottling, very fine grained to subaphanitic; contains abundant detrital 

quartz (as much as 50 percent) 

ranging in grain size from silt 

to very fine; contains stromatoporoids, Alveolites sp., Syringopora? sp., 

partly silicified; weathers light olive 

gray. (T57-392)__________________ 2 

15. Sandstone, grayish-pink ( 5R 8/2), poorly sorted, medium- to coarse-grained; 

consists of tightly packed quartz 

grains ranging from 0.05 to 1 mm in 

diameter ; most grains are larger than 

0.2 mm and are rounded to subrounded ; thin-bedded ; poorly exposed; weathers pale brown. (T57-

391) -------------------·------------ 7 

14. Dolomite, light olive-gray (5Y 6/1) 

with light brownish-gray (5YR 6/1) 

streaks, very finely crystalline; contains large calcite drusen as much as 

2 in. in diameter; thick-bedded; 

weathers pale yellowish brown. 

(T57-390) -------------·------------ 9 

13. Limestone and calcitic dolomite, mottled 

grayish-red ( 5R 4/2) and light 

brownish-gray (5YR 6/2), finely crystalline, argillaceous; contains silicified fragments of Thamnopora? sp. 

and crinoid ossicles; scattered large 

calcite druses (as much as 2 in. in 

diameter) ; thick-bedded; weathers 

pale brown. (T57-389) ------------ 12 

12. Dolomite, grayish-pink ( 5R 8/2, very 

finely crystalline ; contains a very 

small amount of silt-sized detrital 

quartz; middle part of subunit is 

thick bedded ; lower and upper parts 

are thin bedded; stylolitic near top; 

weathers yellowish gray. ( T57 -388) _ 22 

11. Poorly exposed interval; contains at 

least one bed of dolomitic sandstone, 

pinkish-gray (5YR 8/1); mediumto coarse-grained; contains rounded to 

745-106 o-64---4 

Cumulative 

thickness 

(feet) 

234+ 

232+ 

222+ 

220+ 

213+ 

204+ 

192+ 

SECTION 29.-Thompson Wash-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

11. Poorly exposed interval, etc.-Con. 

subrounded quartz grains embedded 

Sub-

'unit 

thickness 

(feet) 

in much dolomitic matrix, whioh is 

finely crystalline; quartz grains have 

little or no surficial etching; weathers 

grayish brown. (T57-387) --------- 10 

10. Covered ; probably underlain by finely 

saccharoidal dolomite_______________ 20 

9. Dolomite, pale-red ( 5R 6/2), very finely 

crystalline; contains scattered small 

calcite vugs and veins; medium-bedded; weathers light brown. (T57-

386) ------------------·------------- 15 

8. Dolomite, mottled pale-red 5R 6/2) and 

pinkish-gray (5YR 8/1), very finely to 

finely crystalline ; contains a small 

amount (1 percent) of silt and a few 

very fine detrital quartz grains; thinbedded; weathers light brown. (T57-

385) ------------------·------------- 5 

7. Covered ; probably dolomite similar to 

subunit 6--------------------------- 10 

6. Dolomite, light brownish-gray (5YR 

6/1), finely crystalline, medium-bedded, poorly exposed; weathers light 

brown. (T57-384) ----------------- 10 

Aphanitic dolomite unit (sandstone facies:) : 

5. Shale, fissile siltstone, and hard sandstone beds %-1 :ft thick and 4-5 ft 

apart; sandstone, pale red-purple 5RP 

6/2) to yellowish gray (5Y 7/2) ; 

coarse-grained, poorly sorted ; contains ~angular to subrounded quartz 

grains as much as 1 mm in diameter; 

contains a·bundant chert and quartzite 

granules and pebbles as much as 5 mm 

in diameter. (T57-401, 404, 405) ____ 25 

4. Dolomite, pinkish-gray ( 5Y R 8/1), interbedded with silty sandstone ; argillaceous ; contains abundant detrital 

quartz grains and chert fragments, unsorted, angular to rounded, as much 

as 1 mm in diameter; thin-bedded 

(beds are 6 in.-1 :ft thick) ; weathers 

light brown. (T57-403) ------------ 10 

3. Sandstone, yellowish-gray (5Y 8/1), in 

part laminated and mottled pale red 

(lOR 6/2), medium- to coarse-grained 

composed generally of pure quartz 

sandstone having subangular to subrounded grains ; interbedded layers 

containing detrital chert fragments 

occur 10 feet above base horizon and 

have abundant unidentified arthrodiran plates preserved as casts; thickbedded; highly crossbedded; weathers 

pale brown. (T57-400, 399, 402) ___ 25+ 

139 

Cumulative 

thickness 

(feet) 

170+ 

160+ 

140+ 

125+ 

120+ 

110+ 

100+ 

75+ 

65+ 
140 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 29.-Thompson Wash-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

2. Sandstone, very coarse, arkosic, grayishorange (lOYR 7/4) to grayi·sh orangepink (5YR 7/2) ; contains poorly 

sorted angular to suhangular grains 

of quartz and feldspar and a minor 

amount of chert fragments as large as 

Subunit 

thickness 

(feet) 

15 mm in diameter ; grades upward 

into medium-grained sandstone; medium- to thick-bedded; weathers light 

brown. ( T57-406) ----------------- 30 

1. eonglomerate, consists of densely 

packed pebbles composed of quartzite 

·and of igneous rocks________________ 10 

Precam'brian: Granite. 

SECTION 30.-Diamond Point 

Cumulative 

thickness 

(feet) 

40 

10 

[Escarpment below Diamond Rim, 0.5 mile northwest of Diamond Point 

(Pr()montory Butte quadrangle, Gila County, NWlA, sec. 23, T. 11 N., 

R. 11 E.). Photograph lots AK 3118, 3119. Mea,sured by R. L. Harbour, 1956; additi()nal observations by Curt Teichert. 1957] 

Martin Formation: Sub- Cumuunit Zative Jerome Member: 

Upper unit (top of section eroded; subunit 46 

is probably near top of upper unit) : 

46. Limestone, dolomitic, pale-red (lOR 

6/2), finely to medium crystalline; 

very fossiliferous, crinoidal, containing stromatoporoids, large Syringopora colonies ; Disphyllum sp. BreviphylZum? sp., and silicified brachiopods (Atrypa sp.) ; thin-bedded; 

weathers pale red. (T56-523) _____ _ 

45. Covered ----------------------------- 44. Dolomite, pale-red, finely crystalline; 

contains silicified brachiopod fragments and small crinoid stems ; thinbedded. (T56-525) _______________ _ 

43. Shale, pale red-purple; poorly exthick- thick- ness 

(feet) 

6 

4 

5 

ness 

(feet) 

448 

442 

438 

posed ----------------------------- 13 433 

42. Dolomite, breccious, grayish-pink. finely 

crystalline ; contains brachiopod fragments and large crinoid stems, which 

were converted to chert ; thin-bedded. 

(T56-524)------------------------- 5.5 420 

41. Covered----------------------------- 8 414.5 

40. Sandstone, medium light-gray, very fine 

grained, fissile_____________________ 0.5 406.5 

39. Dolomite, mottled pale-red (lOR 6/2) 

and pale red-purple (5R 6/2), finely to 

medium crystalline; contains stromatoporoids, bryozoan ( Fenestella) , and 

brachiopod fragments. ( T56-524-

218) ------------------------------ 4 406 

38. Covered----------------------------- 8 402 

37. Dolomite, pale-red, saccharoidal, lamilllated, resistant____________________ 3 394 

36. Limestone, medium light-gray, aphanitic; contains clUJSters of Aulopora____ 1 391 

35. Dolomite, pale-red, saccharoidal, very 

thinly and irregularly bedded_______ 2 3HO 

SECTION 30.-Diamond Point-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

34. Dolomite, pale-red (lOR 6/2) to grayish 

orange-pink (5YR 7/2), finely to medium crystalline ; contains as much as 

10 percent detrital quartz grains, 

poorly sorted, ranging in size from 

silt to 0.5 mm in diameter; larger 

grains, well rounded and shattered; 

weathers light brown. (T56-217) __ _ 

33. Dolomite, mottled medium;:..gray and 

pale-red, finely crystalline, sandy, 

thin-bedded, pool'lly exposed ________ _ 

Subunit 

thickness 

(feet) 

2 

13 

32. Dolomite, pale-red, saccharoidal; contains a few angular fragments of finegrained dolomite; two resistant beds 3 

31. Dolomite, light brownish-gray (5YR 

6/1), very finely crystalline ; contains 

a very small amount of detrital quartz 

grains (less than 1 percent) , angular, 

which are as much as 0.15 mm in diameter except in uppermost foot, 

where rounded quartz grains as 

much as 1 mm in diameter are present; thin-bedded (beds are 6 in. 

thick) ; weathers light brown. (H56-

216) ------------------------------ 12 

30. Limestone, medium-gray, fine-grained, 

very thinly bedded, poorly exposed___ 3 

29. Dolomite, grayish orange-pink ( 5Y R 

7/2), very sandy ; contains much 

finely crystalline dolomitic cement ; 

quartz grains poorly sorted and as 

much as 1 mm in diameter ; ·grains 0.3 

mm and larger are generally well 

rounded; contain scattered fragments 

of dolomite as much as 2 in. in diameter ; forms one resistant bed having 

well-formed current bedding. (H56-

215) -------------------·------------ 6 

28. Dolomite, light brownish-gray (5YR 

6/1), upper part mottled yellowishgray and pale-red, very finely crystalline ; contains a very small amount 

of silt-sized detrital quartz; thinbedded (beds are less than 1 ft thick) ; 

weathers light brownish gray to yellowish gray. (H56-214, 213') ------- 22 

27. Dolomite, pale red-purple (5RP 6/2) ; 

very finely crystalline. Lower part 

contains very scattered detrital angular quartz grains as much as 0.1 mm 

in diameter; upward in subunit, detrital component increases to as much as 

2 percent, and subunit contains subrounded grains as much as 0.5 mm in 

diameter ; upper 3 ft constitute one 

bed; weathers grayish pink. (H56-

212, 211)-------------------------- 21 

26. Dolomite, grayish-pink, very finely crystalline, thick-bedded________________ 4 

Cumulative 

thickness 

(feet) 

388 

386 

373 

370 

358 

355 

349 

327 

306 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 

SECTION 30.-Diamond Point-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

Sub-

•unit 

thick25. Limestone, dolomitic, grayish orangepink (5YR 7/2) ; subaphanitic limestone matrix ; contains a large amount 

(as much as 50 percent) of small idiomorphic dolomite crystals about 0.1 

mm in diameter; crops out as two 

beds. (II56-210) _________________ _ 

24. Limestone breccia, mottled various 

shades of gray ; contains fragmental 

brachiopods and crinoids ; crops out 

as two beds------------------------

23. Limestone, dolomitic, grayish orangepink ( 5Y R 7/2) and yellowish-gray 

(5Y 7/2), very finely crystalline, very 

sandy ; grades u,pward into very fine 

grained dolomitic sandstone; matrix, 

finely to medium crystalline; detrital 

quartz grains are generally less than 

ness 

(feet) 

5 

5 

0.1 mm in diameter, angular; laminated; contains scattered large calcite 

drusen. (II56-209, 208)------------ 20 

22. Siltstone, light-gray, fissile, argillaceous, poorly exposed ____________________ _ 

Aphanitic dolomite unit: 

21. Limestone, medium-gray, aphanitic, 

laminated _______ -------------------

20. Dolomite, pale-red, very finely crystalline, thin-bedded (beds are 3 in. 

thick) ____________________________ _ 

19. Limestone, medium-gray ( N 5), subaphanitic; contains scattered dolomite 

rhombohedra as much as 0.05 mm in 

diameter; contains fragments of 

ostracode shells and a few small calcispheres less than 1 mm in diameter ; 

thin- to medium-bedded (beds are 6 

4 

1 

2 

in. to 2ft thick) ; weathers light olive 

gray. (II56-207)__________________ 8 

18. Dolomite, grayish-pink (5R 8/2), subaphanitic; subconchoidal fracture; 

contains a very few quartz grains 0.07 

mm and less in diameter ; a few grains 

are as much as 0.3 mm; mediumbedded (beds are 2 ft thick) ; weathers light gray. (II56-206) --------- 8 

17. Dolomite, pinkish-gray ( 5Y R 8/l), subaphanitic, very sandy ; contains detrital quartz grains as much as 1 mm 

in diameter, which are abundant 

throughout subunit and are concentrated in lenses and layers so as to 

form dolomitic sandstone ; most large 

grains are rounded to subrounded ; 

thin-bedded; weathers brownish gray. 

(II56-205) _________________________ 10 

16. Sandstone, pale-red (lOR 6/2), poorly 

sorted, medium- to coarse-grained; 

contains tightly packed quartz grains, 

which are subangular to subrounded 

and badly shattered; medium-bedded 

Cumulative 

thickness 

(feet) 

302 

297 

292 

272 

268 

267 

265 

257 

249 

SECTION 30.-Diamon.d Point-Continued 

Martin . C t• d Sub- Formatwn- on mue unit 

Jerome Member-Continued t!!~~-

Aphanitic dolomite unit-Continued (feet) 

16. Sandstone, etc.-Continued 

(beds are 2 ft thick) ; forms prominent cliffs; weathers pale red. 

(II56-204) _________________________ 26 

15. Dolomite, mottled pinkish-gray ( 5Y R 

8/1), light brownish-gray (5YR 6/1), 

pale-red (5R 6/2), and grayish-red 

( 5R 4/2) ; middle part grayish pink 

( 5R 8/2) ; mottling results from irregular staining by iron oxide ; very 

fine grained to subaphanitic; in places 

subeonchoidal fracture ; silty ; middle 

part of subunit contains scattered angular to subangular quartz grains as 

much as 0.15 mm in diameter ; thinto thick-bedded (beds are 6 in. to 3 

ft thick) ; contains shale layers as 

much as 6 in. thick separating major 

beds ; weathers generally yellowish 

gray to brownish gray. ( II56-203-

202, 201) -------------------------- 44 

14. Dolomite, mottled pale-red (5R 6/2) 

to grayish-red (5R 4/2), very fine 

grained, silty ; mottling results from 

irregular staining by iron oxide. 

( II56-200) -------------------·------ 4 

13. Limestone, dolomitic, pale red-purple 

( 5RP 6/2), very fine grained ; subconchoidal fracture; contains scattered dolomite rhombohedra as much 

as 0.05 mm in diameter ; silty, containing very little fine grained detrital quartz; somewhat microbreccious texture; contains scattered 

small ostracode shell fragments; thinbedded; weathers pinkish gray. 

(II56-199)------------------------- 6 

12. Covered------------·----------------- 3 

11. Dolomite, light brownish-gray (5YR 

6/1) and light-gray (N 7) with palered mottles, subaphanitic to very fine 

grained ; subconchoidal fracture ; 

practically free from detrital quartz 

.except in uppermost part, where very 

scattered angular quartz grains as 

much as 0.3 mm in diameter are present; medium-bedded (beds are 1 ft 

thick), beds are separated by thin 

shaly layers; weathers pinkish to 

yellowish gray. (II56-198, 197, 196) -- 36 

10. Dolomite, medium light-gray (N 6), 

aphanitic ; conchoidal fracture ; contains small chert pebbles having 

brown rinds ; contains a very small 

amount of silt and very fine sand scattered throughout rock except in upper 

2 ft which is more sandy ; thin bedded-layers less than 6 in. thick, separated by shale layers less than 1 in. 

thick; weathers yellowish gray. (II56-195) ________________________ _ 10 

141 

Cumulative 

thickness 

(feet) 

239 

213 

169 

165 

159 

156 

120 
142 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 30.-Diamond Point-Continued 

Martin Formation-Continued 

J erQme Member-Continued 

Fetid dolomite unit: 

9. Dolomite, pale yellowish-brown (lOYR 

6/2) to grayish orange-pink (5YR 

7/2), fine- to medium-crystalline, 

finely laminated; fetid odor; somewhat porous ; contains calcite vugs; 

contains light-gray chert lenses as 

much as 1% ft. in diameter; thin- to 

thick-bedded (beds are 3 in. to 3 ft 

thick) ; weathers pale yellowish 

Sub-

•unit 

thickness 

(feet) 

brown. (II56--194, 193) ____________ 20 

Beckers Butte Member: 

8. Sandstone, pale-red (5R 6/2), fine- to medium-grained; has a calcareous matrix; 

contains poorly sorted clusters of tightly 

packed angular to subangular and a few 

subrounded quartz grains ; friable; medium-bedded (beds are 1 ft thick); 

weathers pale red. (II56--192) ---------- 15 

7. Sandstone, mottled pale-red and lightbrown, poorly sorted, fine-grained to 

conglomeratic; contains pebbles as much 

as 8 mm in diameter; crops out as one 

bed------------·---------------------- 5 

6. Dolomite, light-brown (5YR 6/4) with 

grayish-red (lOR 4/2) mottling, very 

fine grained, calcitic, argillaceous; contains scattered angular quartz grains as 

much as 0.5 mm in diameter; thin-bedded; weathers light brown. (II56--191; 

T57-349) -----------·------------------ 9 

5. Sandstone, pale-red (lOR 6/2), genel"'ally 

fine-grained to ·silty; contains scattered 

angular quartz gr'ains as much as 1 mm 

in diameter; thin-bedded ; weathers 

paJe red. (II56--190; T57-348) -------- 5 

4. Sandstone -and siltstone, grayish-red 

(5R 4/2 to lOR 4/2) ; •siltstone layers 

oontain angular to .subangular fragments of quartz and chert as much as 2 

mm in diameter and ·are int·erbedded 

with conglomeratic !·ayers; very crosrsbedded; poorly exposed. (T57-347) __ 12 

3. Sandstone, greyish orange-pink (lOR 8/2) 

·and yellowish-gray ( 5Y 8/1), very 

coorse-grained ; conlt!aiDJS angular pebbles of quartz ·and quartzite as much 

as 10 mm in di'ameter; very crossbedded; thick-bedded (beds are generally 2-3 ft thick ; baSial bed is 5 fit 'tJhick) . 

(T57-346)----------- ---------------- 18 

2. Sandstone, grayish-red ( 5R 4/2) , coarsegrained, arkosic, ·slightly crossbedded ; 

contains pebbles of quartz and quartzite 

as much as 5 mm in diameter; so:flt and 

nonresistant; bedding obscure. (T57-

345)--------------------------------- 14 

1. S·andstone, pale-red, coarse and conglomeratic; con'tains angular qunrtz 

pebbles as much as 8 em in diameter; 

very poorly exposed__________________ 12 

~reoombri'an: Granite. 

Cumulative 

thickness 

(feet) 

110 

90 

75 

70 

61 

56 

44 

26 

12 

SECTION 31.-Webber Creek 

[Bed and west bank of Webber Creek, 0.2-1.4 miles south of crossing of 

road from Pine to Kohl Ranch (Pine quadrangle, sec. 5, T. 11¥.! N., 

R. 10 E., unsurveyed). Photograph lots AK 3083, 3084. Measured 

by CUrt Teichert, 1953; additional observations, 1956] 

M:a.rtin ~ormation : Sub-

'unit Jerome Member: thickUpper unit: <i~!~) 

37. DolomirtJe, calcite, medium light-gray 

(N 6) to light olive-gray (5Y 6/1), 

very fine grained ; in upper 25 f't. 

interbedded with dolomitic shale; 

lower part contains some fine- to medium-grained Slaccharoidal beds; 23-

33 ft above base, silicified brachiopods occur, most of which are 

un'idell!tifilable but . including a large 

species of Atrypa; woo.thers yellowish 

gray. (This subunit could probably 

be further subdivided but is 'Uoo 

poorly exposed.) ('T56-517 ; TP366)------------------------------- 57 

36. S·andstone, light-grlay, fine-grained, 

thin-bedded; has large ripple marks 

Cumulative 

thickness 

(feet) 

437 

crests 1-1% in. apart)------------- 6. 5 380 

35. Dolomite, pale-red, medium-grained, 

·Siacchia:roidai, thin-bedded___________ 5 

34. Dolomite, pale-red (10 R 6/2) and lightgray ( N 7) , very fine grained to 

dense; contains abundant detrital 

quartz grains, unsorted, ranging in 

size from silt to about 0.75 mm i'n 

diameter ; grains greater than 0.2 mm 

in size are generally well rounded to 

subrounded ; smaller grains are angola r to subangular ; many grains show 

peripheral replacement by dolomite; 

contains large globular stromatoporoids; medium-bedded (beds are 4-10 

in. thick); weathers medium gray. 

373.5 

( T56--519) -------------------------- 7. 5 368. 5 

33. Sandstone, calcareous, medium lightgray, medium grained becoming increasingly more fine grained towards 

top; contains a few well-rounded 

large quartz grains in a very fine 

groundmass------------------------ ~~ 361 

32. Dolomite, mottled grayish-pink ( 5R 

8/2), light-gray, and medium lightgray ( N 6--7) ; gray parts very fine 

grained ; pink parts somewhat coarser 

grained; contains large calcite drusen 

as much as 10 in. in diameter ; medium-bedded ; weathers light brown. 

(T56--522) -------------------------- 14 336 

31. Limestone, light olive-gray (5Y 6/1), 

dense ; contains some scattered dolomite rhombs 0.05-0.2 mm in diameter; 

has many microfossils ( UmbeZZa, ostracode shells, and tiny gastropod 

shells) ; medium-bedded; weathers 

grayish brown. (T56-521)--------- 5 322 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 143 

SECTION 31.-Webber Creek-Continued 

Martin Formation-Continued ~~fi ~:~:~ 

Jerome Member-Continued t~!~!- t;:;;:-

Upper unit-Continued (feet) (feet) 

30. Dolomite, calcitic, yellowish-gray ( 5Y 

8/1) to pinkish-gray ( 5Y R 8/1), very 

fine grained; rather intimate mixture 

of crystalline dolomite and calcite; 

contains Large ramifying calcitic 

structures as much as 4 in. in diameter simulating fossils; 2 ft below top 

is 10-in. layer containing silicified 

stromatoporoids and large Thamnopora fragments; thick-bedded; weathers yellowish gray. (T56-520) ------ 11.5 317 

29. Dolomite, light-gray, fine-grained, medium-bedded________________________ 10. 5 305. 5 

28. Dolomite, light gray, very fine grained, 

thin-bedded; upper part liminated___ 7. 5 295 

27. Dolomite, medium light-gray, finely 

brecciated__________________________ 0.5 287.5 

26. Dolomite, medium light-gray, dense; 

conchoidal fracture; massive; weathers light gray----------------------

25. Dolomite, mottled pale-red and lightgray, very fine grained, hard, very 

finely laminated; contains some 

slump structures and some Galcite 

vugs ; top layer brecciated _________ _ 

24. Covered interval; probably fine-grained 

gray dolomite--·---------·-----------

23. Sandstone, medium light-gray, evenly 

medium-grained ; contains calcareous 

cement; generally thick-bedded, becoming more medium bedded toward 

top; "worm tracks" seen on some bed7.5 287 

3 279.5 

10.5 276.5 

ding planes________________________ 35 266 

22. Limestone, slightly dolomitic, light-gray 

(N 7) to grayish orange-pink (5YR 

7/2), very fine grained; the lightgray beds tend to be laminated and 

have thin layers of fine grained detrital quartz ; the amount of detrital 

quartz increases in upper 8 ft. or so. 

Thick-bedded mudcracks on bedding 

planes seen in fallen blocks. Wea,thers light brown ( T56-516) ---------- 38 231 

21. Shale, sandy, red-tinted_______________ 4 193 

20. Dolomite, fine-grained, silty, mottled 

grayish-pink and pale-red (lOR 6/2) ; 

matrix consists of a uniform mixture 

of idiomorphic and hypidiomorphic 

dolomite crystals ; contains abundant 

detrital quartz of silt size, only very 

few grains are as much as 0.3 mm in 

diameter ; contains large fragmentary 

bone plates in the uppermost beds ; 

thick-bedded; weathers pale red to 

light brown (TP 335; T56-514, 515·) __ 17 189 

19. Sandstone, poorly exposed____________ 4 172 

Aphanitic dolomite unit: 

18. Dolomite, calcitic, pale-red (5R 6/2), 

very fine grained, argillaceous ; has 

irregular pattern of darker red vugs 

and veinlets ; contains some veinlets 

SECTION 31.-Web·ber Creek-Continued 

Martin Formation~Oontinued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

18. Dolomite, etc.-Continued 

of white calcite; thick-bedded; weathers pale red. Outcrops are disconnected. ( T334) ----------··--------- 17. Covered intervaL ___________________ _ 

16. Limestone, dolomitic ; pinkish-gray 

(5YR 8/1), generally aphanitic, subconchoidal fracture ; contains some 

bands of fine-grained limestone ; contains many vugs as much as 2 em in 

diameter filled with calcite and chert ; 

thick-bedded (beds as 1-3 ft thick) ; 

Subunit 

thickness 

(feet) 

10 

9 

OumuZative 

thickness 

(feet) 

168 

158 

weathers medium gray. (T56-513)_ 16.5 149 

Fetid dolomite unit: 

15. Limestone, medium-gray (N 5) to medium dark-gray (N 4), very fine grained 

to dense, laminated ; lamination 

caused by very thin wavy dark-brown 

layers, probably consisting of some organic material; thin, platy; emits 

strong fetid odor when struck with 

hammer; weathers medium dark 

gray. (T56-512)------------------- 7.5 132.5 

14. Dolomite breccia, light, gray_________ 1 125 

13. Dolomite, calcitic, laminated lightbrown (5R 6/4), light brownish-gray 

(5YR 6/1), and light-olive-gray (5Y 

6/1) ; very fine grained; contains 

local concentrations of idiomorphic 

dolomite crystals ; lower part has 

many calcite vugs and one bed containing ovoid bodies of brecciated 

chert about 8-10 inches long; appearance in outcrop is thick bedded, 

but on weathering, rock ·breaks up into 

thin plates; faint ripple marks occur 

in places on bedding planes; emits 

slightly fetid odor when struck with 

hammer; weathers pale yellowish 

brown. (T56-511)----------------- 10 124 

Beckers Butte Member: 

12. Oovered interval----------------------- 14.5 114 

11. Limestone, yellowish-gray (5Y 8/1), very 

fine grained ; groups of grains lie in 

identical optical orientation, forming 

refiecting planes on fresh surfaces 

(luster mottling) ; laminated, thinbedded; weathers olive gray. (T56-

510) -------------------------------- 3 99.5 

10. Sandstone, mottled light-brown, pale-red, 

and orange medium-grained__________ 4 96. 5 

9. Dolomite, grayish-pink (5R 8/2), alternating with calcareous shale, grayish yellow-green (5GY 7/2). Dolomite beds 

are very fine grained ·to dense and contain scattered silt-size detrital quartz 

particles, which constitute ·as much as 

10 percent of the rock. The dolomite 

weathers pale red; the shale weathers 

light brown to reddish brown. ( T56-

508, 509) ---------------------------- 8. ·5 92. 5 
144 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 31.-Webber Creek-Continued 

Martin Formation-Continued 

Subunit 

thickBeckers Butte Member-Continued t};;:) 

8. Dolomite, slightly calcitic, very sandy, 

grayish-pink (5R 8/2) ; matrix dense; 

contains abundant detrital quartz and 

other mineral grains that are unsorted, 

range in size from silt to about 0.5 mm 

in diameter, are angular to subrounded, 

and make up as much as 15 percent of 

the rock mass ; fiaggy to shaly ; 

weathers light brown. (T56-507) ----- 2 

7. •S·andstone, grayish-red ( 5R 4/2), fine- to 

coarse-grained, conglomeratic in part, 

very poorly sorted, arkosic; contains 

grains of all sizes that are angular to 

subangular; medium-bedded (beds are 

8-10 in. thick) ; weather·s light brown. 

(T56-506) -------------------------- 6 

6. S·imdstone, pale-red, -alternating with 

sandy shale, gray ; lithologic types like 

subunits 4 and 5--------------------- 7.5 

5. Shale, gray, sandy--------------------- 1 

4. ·Sandstone, mottled pale-red (5R 6/2) and 

moderate-pink (5R 7/4), mostly fine 

grained; has a slightly calcareous cement; contains detrital quartz grains 

generally about 0.1 mm in diameter and 

a few as large as 0.5 mm ; flaggy ; 

weathers light brown. (TL 333) _____ 2 

3. Sandstone, yellowish-gray, coarse to very 

coarse; very cross-bedded; contains 

conglomeratic layers that have pebbles 

2-3 em in diameter; thick-bedded (beds 

are 1-5 ft thick) ; weathers brown____ 54. 5 

2. Sandstone, yellowish-gray, somewhat 

arkosic, thin-bedded to platy--------- 7. 5 

1. Sandstone and 'breccia, grayish-red (lOR 

4/2)-except basal layer, which is yellowish gray (5Y 7/2)-generally coarse 

grained to very coarse grained; contains some fine grained layers ; contains angular fragments of red-tinted 

chert and quartz as much as 4 in. in 

diameter; thick-bedded; weathers light 

OumuZative 

thick· 

ness 

(feet) 

84 

82 

76 

68.5 

67.5 

65.5 

11 

brown to grayish red________________ 3. 5 3. 5 

Precambrian: Granite, deeply weathered. 

SECTION 32.-East Verde River 

[On north side of East Verde River. about half a mile east of PaysonPine Road bridge and about 1 mile north of same bridge along east 

side of Sycamore Creek (Pine quadrangle, NW:JA sec. 17 and SW:JA 

sec. 8, T. 11 N., R. 10 E., unsurveyed). Photograph lots AK 3115, 

3116. Partly measured by Curt Teichert, 1953. Upper unit adapted 

from Huddle and Dobrovolny, 1952, p. 104-105. Brackets surrounding rQck names indicate that the lithology of the rock has not been 

checked ; some of the "limestones" are dolomites or calcitic dolomites] 

Martin Formation: SubJerome Member: ~~?~i. 

Upper unit: <j;;:) 

35. Siltstone, banded gray and greenishgray, calcareous; massive in fresh 

outcrops, but thin bedded and sh'aly 

where weathered; weathers light gray 16 

Cumulative 

thickness 

(feet) 

437 

SECTION 32.-East Verde River-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

34. [Limestone] yellowish- ·and reddishbrown, finely crystalline, very S'andy ; 

fossiliferous, containing corals (Pachyphyllum sp., H emagonaria sp., Thamnopora sp.) and brachiopods. (T-321 

and 324) -------------------------- 33. [Limestone] greenish-gray, very finegrained, cherty, fossiliferous; con- a few shaly partings _______________ _ 

32. [Limestone] gray, medium-crystalline; cherty at top; contains silicified fossils ________________________ _ 

31. Mostly concealed; forms ledges of yellowish-brown calcareous sandstone 

containing quartz geodes; fossilifSubunit 

thickness 

(feet) 

2 

OumuZative 

thickness 

(feet) 

421 

7.5 419 

2.5 411.5 

erous -----------------------------· 38 409 

30. [Limestone] white to grayish-brown, 

finely to medium-crystalline, sandy 

in part ; has layers of rounded 

frosted quartz grains; thin- to medium-bedded ; contains silicified 

tabulate corals (Pachyphyllum 

sp.) near middle ; upper part partly 

concealed; weathers buff___________ 33 371 

29. [Limestone, dolomitic] light-brown, 

finely to medium-crystalline; has calcite-lined cavities and small quartz 

geodes; 50 percent concealed; weathers buff___________________________ 37 338 

28. [Limestone] gray, fine-grained, sandy 

and silty, thin-bedded; weathers grayish brown__________________________ 22 301 

27. Sandstone, gray to pink, with streaks 

of brown along bedding; :finegrained ; very calcareous ; massive ; 

forms prominent rounded outcrops; 

contains numerous calcite-filled 

cavities____________________________ 8 

26. [Limestone] gray to brown, dense to 

fine-grained, sandy, thin-bedded; 

about 40 percent concealed; weathers gray to buff____________________ 28 

25. [Limestone] grayish-white, mottled red, 

fine-grained, sandy, silty; contains 

scattered rounded frosted quartz 

grains; mostly massive_____________ 6 

Aphanitic dolomite unit: 

24. Limestone, light-gray, aphanitic; contains a few sea ttered very small 

quartz grains_____________________ 2 

23. Limestone, slightly dolomitic, pinkishgray (5YR 8/1) with brownish 

stains, very fine grained, thinbedded. (T-318)__________________ 2 

22. Limestone, medium dark-gray (N 4), 

aphanitic; conchoidal fracture; contains abundant ostracodes (Hypotetragona sp.) , places forming a microcoquina; thick-bedded; weathers 

yellowish gray. (T-317) ----------- 8 

279 

271 

243 

237 

235 

233 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 145 

SECTION 32.-East Verde River-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Sub-

'Unit 

thickAphanitic dolomite unit-Continued (j!!:) 

21. Limestone, dolomitic, pinkish-gray 

(5YR 8/1), subaphanitic; subconchoidal fracture; contains a few wellrounded quartz grains at bottom, increasing in quantity toward top; 

thin-bedded (beds are 4-8 in. 

thick)------------------------------ 4 

20. Limestone, medium-gray, aphanitic; 

conchoidal fracture ; mudcracks 

occur on one bedding plane near 

base of subunit; thin-bedded (beds 

are 4-8 in. thick)------------------- 6 

19. Limestone, pinkish-gray, finely crystalline; contains abundant detrital 

quartz______________________________ 1 

18. Sandstone, medium-gray, hard, calcareOumuZative 

thickness 

(feet) 

225 

221 

215 

ous _______________________________ _ 

17. Covered _____________________________ _ 

16. Dolomite, medium-gray, aphanitic ___ _ 

1 214 

5.5 213 

1.5 207.5 

15. Sandstone, light-gray to pale-pink; contains calcareous matrix; lower twothirds thin bedded (beds are as 

much as 1 ft thick)-----------------

14. Siltstone, pale-purple ________________ _ 

13. Sandstone, pinkish-gray ( 5Y R 8/1), 

well-sorted, very fine grained ; contains scattered grains as much as 

0.5 mm in diameter; grains subangular to subrounded ; weathers light 

7 206 

3 199 

brown. (T-316) ------------------- 16 196 

12. Dolomite, light-gray, subaphanitic, medium- to thick-bedded; weathers into 

small angular chips_________________ 10 180 

11. Dolomite, medium-gray, aphanitic, 

conchoidal fracture; contains abundant detrital quartz in lower 5 ft; 

medium-bedded_____________________ 16 170 

10. Limestone, mottled grayish-red (5R 

4/2) and light olive-gray (5Y 6/1), 

subaphanitic ; contains abundant 

small dolomite rhombohedra. In part 

the subunit is a microcoquina composed of ostracode shells and small 

calcispheres. Contains a few specimens of Umbella?. (T-313) ________ 12 154 

9. Dolomite, medium light-gray, aphanitic; conchoidal fracture; thin-bedded; weathers light gray----------- 23 142 

8. Dolomite, light olive-gray (5Y 6/1), 

·subaphanitic ; several beds contain 

calcite vugs and stringers; mediumbedded; weathers yellowish gray____ 18. 5 119 

7. Dolomite, light-gray, aphanitic, :flaggy __ 3. 5 100. 5 

6. Sandstone, light brownish-gray (5YR 

6/1), poorly sorted; grains are subrounded to subangular and are as 

much as 0.3 mm in diameter ; contains much carbonate (calcitic dolomite) matrix; thick-bedded; hard; 

weathers light brown. ( T-312) ____ 1. 5 97 

SECTION 32.-East Verde' River-Continued 

Martin Formation-Continued 

JerQme Member-Continued 

Aphanitic dolomite unit-Continued 

5. Dolomite, light brownish-gray ( 5Y R 

6/1), subaphani tic ; subconchoidal 

fracture; contains many chert concretions as much as 6 in. in diameter ; 

thin-bedded, breaks up into small 

flakes ; weathers yellowish brown. 

(T-311)----------------------------

Fetid dolomite unit: 

4. Dolomite, pale yellowish-brown (10YR 

6/2) to grayish orange-pink (5YR 

7/2), very finely crystalline, laminated; some beds contain abundant 

calcite vugs as much as 6 mm in diameter ; fetid odor ; generally thin 

bedded but contains a few thicker 

beds; weathers pale yellowish brown. 

Sub-

'unit 

thickness 

(feet) 

8.5 

OumuZative 

thickness 

(feet) 

95.5 

(T-307, 308,310)------------------- 19 87 

Beckers Butte Member : 

3. Sandstone, calcareous, mottled very pale 

orange (10YR 8/2) and grayish redpurple ( 5RP 4/2) ; the basal and the 

uppermost part of subunit are more 

uniformly light gray; fine-grained, 

well-sorted; partly laminated; thinbedded; weathers grayish orange pink 

( T-306) -------------·--------------- 16 68 

2. Sandstone, arkosic, mottled light-brown 

(5YR 6/4) and grayish orange-pink 

(5YR 7/2) ; basal part conglomeratic 

and contains granules generally 4-5 

mm in diameter and scattered pebbles 

as much as 1 em ; becomes gradually 

more fine grained from bottom to top ; 

upper part of subunit well sorted; finegrained ; thin-bedded ; generally poorly 

exposed. (T-304, 305) ______________ 11 52 

1. Sandstone, grayish-red (5R 4/2), arkosic, 

very coarse grained to conglomeratic; 

poorly .sorted ; contains subangular 

grains as much as 2.5 mm in diameter ; 

contains many quartz and quartzite 

granules as much as 5 mm and some 

pebbles as much as 1 em in diameter; 

medium- to thick-bedded; crossbedded; 

weathers grayish red. ( T303) ------- 41 41 

Precambrian : Granite 

SECTION 33.-UPJPer Sycamore Canyon 

[1.2-1.9 miles downstream from road to Pine-Kohl Ranch,. about 1 mile 

east of Pine-Payson Road (Pine quadrangle, sec. 14, T. 11% N., 

R. 9 E,. unsurveyed). Photograph lots AK 3084, 3085. Measured by 

Curt Teichert and R. L. Harbour, 1956] 

Martin Formation: 

Jerome Member : 

Upper unit: 

41. Limestone, dolomitic, mottled light-gray 

(N 7), pinkish-gray (5YR 8/1), and 

light brownish-gray (5YR 6/1) ; very 

fine grained ; contains a small amount 

(less than 1 percent) of silt-sized 
146 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 33.-Upper Syca·more Canyon-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

41. Limestone, etc.-Continued 

detrital quartz; contains some sandier 

layers ; irregularly thick bedded ; 

weathers pinkish gray to light brownSub-

•unit 

thickness 

(feet) 

ish gray. (T56-536)--------------- 6 

40. Dolomite, strongly calcitic, streaky 

pale-red ( 5R 6/2), very fine grained; 

subconchoidal fracture ; contains 

much silt-sized detrital quartz particles, making up 1-2 percent of rock ; 

slightly laminated appearance; medium-bedded; weathers pinkish gray. 

(T56-535) ----------·--------------- 15 

39. Dolomite, pale-red (lOR 6/2) ; composed 

of a fine-grained mosaic of tightly 

interlocking allomorphic dolomite 

crystals and a little interstitial calcite; contains a small amount of detrital quartz grains ranging in grain 

size from silt to fine, mostly subangular to subrounded, composing not 

more than 1 percent of rock mass; 

contains a few unidentified silicified 

brachiopod fragments ; medium-size 

vugs; thin- to medium-bedded; 

weathers light brown. (T56--534) __ 7 

38. Limestone, somewhat dolomitic ; palered-purple (5RP 6/2), very fine 

grained; contains scattered finegrained laminae ; subconchoidal fracture; has a few calcite vugs; thinto medium-bedded; weathers light 

brown______________________________ 9 

37. Dolomite, mottled grayish-pink (5R 

8/2) and pale-red ( 5R 6/2) , very fine 

grained ; contains sandy layers as 

much as 3 or 4 mm thick composed 

of detrital quartz grains ranging in 

size from silt to more than 1 mm in 

diameter ; larger grains are well 

rounded and have frosted surfaces; 

peripheral replacement of silica by 

dolomite is common; rich in silicified 

brachiopod shells ( Theodossia and 

others) ; medium- to thick-bedded and 

locally cliff-forming; weathers yellowish gray. (T56--532) --------------- 3 

36. Dolomite, mottled grayish-brown and 

light purple ; the lower part is thin 

bedded, upper part is medium bedded ; 

poorly exposed_____________________ 5 

35. Dolomite, medium light-gray, dense, 

flaggy; weathers light gray. (T56-

531) ------------------------------- 10 

34. Dolomite, grayish-pink (5R 8/2) to palered (5R 6/2), fine- to mediumgrained ; composed mostly of hypidiomorphic dolomite crystals and very 

little interstitial calcite; contains a 

small amount of detrital quartz rangCumulative 

thickness 

(feet) 

467 

461 

446 

439 

430 

427 

422 

SECTION 3'3.-Upper Sycamore Canyon-Continued 

Martin Formation-Continued 

Jergme Member-Continued 

Upper unit-Continued 

34. Dolomite, etc.-Continued 

ing in grain size from silt to very fine 

that constitutes no more than 1 percent of rock mass ; contains microstylolites; thin-bedded; wea.thers 

very pale orange; poorly exposed. 

Sub-

•unit 

thickness 

{feet) 

(T56-531) ------------------------ 2 

33. Dolomite, yellowish-gray, coarsegrained, very sandy, medium-bedded 

(bed are 10 in. thick)-------------- 2 

32. Dolomite, slightly calcitic, yellowishgray (5Y 8/1), with small reddishgray spots ; medium- to coarsegrained, saccharoidal ; composed of 

hypidiomorphic dolomite crystals ; 

contains no detrital quartz; thin 

bedded; poorly exposed ; weathers 

yellowish gray. (T56-529) --------- 5 

31. Dolomite, calcitic, mottled and banded 

light brownish-gray ( 5Y R 6/1) and 

yellowish-gray ( 5Y 8/1) , coarse 

grained ; consists mostly of hypidiomorphic dolomite crystals 0.5-1.0 mm 

in diameter; contains much interstitial calcite and no detrital quartz; 

medium-bedded; weathers yellowish 

gray (T56-528) -------------------- 6 

30. Dolomite, pale red-purple (5RP 6/2) ; 

very fine grained; contains a very 

small amount of silt-size quartz detritus; contains numerous calcite-filled 

vugs as much as %, in. in diameter; 

medium-bedded; weathers pinkish 

gray. (T56-527)------------------- 5 

29. Sandstone, dolomitic, yellowish-gray 

(5Y 8/1), coarse grained; matrix 

composed of calcitic dolomite, which 

consists · of idiomorphic to hypidiomorphic dolomite crystals from 0.05 

to 0.75 mm in diameter, containing 

calcitic cement between crystals ; contains unsorted detrital quartz grains 

ranging in size from silt to about 1 

mm in diameter ; grains larger than 

0.25 mm are subrounded to well 

rounded; larger grains have frosted 

surfaces ; some peripheral replacement of silica by dolomite or calcite 

occurs, although not on a large scale ; 

thick-bedded; massive, ledge-forming; weathers light brown. (T56- 526; Il56-244) _____________________ 20 

28. Dolomite, grayish orange-pink (5YR 

7/2), saccharoidal; composed of a 

medium-crystalline aggregate of idiomorphic and hypidiomorphic dolomite 

crystals ; contains an insignificant 

amount of silt-size detrital quartz and 

very few rounded grains as much as 

0.5 mm in diameter; forms one resistCumulative 

thickness 

(feet) 

412 

410 

408 

403 

397 

39~ 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 147 

SECTION 3i3.-Upper Sycamore Oanyo~ontinued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

28. Dolomite, etc.-Continued 

ant bed; weathers yellowish gray. 

(II56-243) ------------------------ 27. Dolomite, mottled pinkish-gray (5YR 

8/1) and yellowish-gray ( 5Y 8/1) ; 

consists of a subaphanitic ground 

mass containing angular and rounded 

grains of aphanitic dolomite as much 

as 1 mm in diameter; contains abundant detrital quartz (as much as 15 

percent), poorly sorted; contains 

rounded grains as much as 0.5 mm in 

diameter; medium-bedded (beds are 

Sub-

'Unit 

thickness 

(feet) 

6 

less than 1 ft thick) ; weathers light 

light olive gray. (II56-242) -------- 6 

26. Covered______________________________ 6 

25. Dolomite, light-gray (N 7) to pinkishgray (5YR 8/1) ; weathers into large 

rounded nodules that are concentrically laminated by pale-red Liesegang 

rings; very finely crystalline; contains less than 1 percent o.f silt-size 

detrital quartz particles; has scattered cavities as much as 5 em in 

diameter filled with white calcite; 

forms one massive bed; weathers 

light brown. (II56-241) ------------ 7 

24. Dolomite, light-gray (N 7), very finely 

crystalline ; contains an insignificant 

amount of detrital quartz grains 

ranging in size from silt to very fine; 

medium-bedded (beds are 1ft thick) ; 

weathers yellowish gray. (II56-240) _ 7 

23. Dolomite, pale-red (5R 6/2) in lower 

part, light gray ( N 7) in upper part, 

saccharoidal; consists of a mediumto coarse-grained mixture of idiomorphic and hypidiomorphic dolomite 

crystals and a small amount of interstitial calcite; contains scattered 

mostly very fine detrital quartz grains 

(about 1-2 percent), and a few angular grains as much as 0.3 mm in diameter; thick-bedded; weathers yellowish brown to grayish orange pink. 

(II56-239, 238)--------------------- 29 

22. Dolomite, slightly calcitic-especially 

in lower part-mottled light-gray 

(N 7) and light brownish-gray (5YR6/l) , more uniformly light gray in 

upper part, very fine grained to subaphanitic; contains varying amounts 

(as much as 10 percent) of detrital 

quartz grains of all sizes (as large as 

0.5 mm in diameter) ; all grains are 

angular to subangular; mediumbedded (beds are 1 ft thick) ; weathers grayish orange pink to light 

brown. (II56-237, 236; Il57-235) ___ 34 

21. Dolomite, pale-red, saccharoidal, sandy, 

poorly bedded______________________ 5 

Cumulative 

thickness 

(feet) 

372 

366 

360 

354 

347 

340 

311 

277 

SECTION 33.-Upper Sycamore Canyon-Continued 

Martin Formation-Continued Sub-

'u.nit 

Jerome Member-Continued thickness Upper unit-Continyed (feet) 

20. Covered---------------·--------------- 10 

19. Limestone, medium light-gray (N 6), 

subaphanitic; has a pelletal texture 

containing sparry calcite between pellets; contains a very small amount of 

detrital quartz, as much as 0.3 mm in 

diameter, angular; one bed weathers 

nodular; weathers light gray. (II56-

234) ----------------·--------------- 5 

18. Dolomite, grayish-pink (5R 8/2) to 

pale-red (lOR 6/2) ; greater part is 

finely crystalline, becoming mediumcrystalline toward top ; near base contains angular pebbles of reddish-gray 

quartzite; lower part is rich in detrital quartz grains of all sizes 0.8 mm 

and les-s ; larger grains rounded ; detrital quartz diminishes in amount 

toward the top of subunit ; very thick 

bedded (beds are 5 ft thick) ; weathers light brownish gray to light olive 

gray. (II56-233, 232, 231) --------- 38 

17. Sandstone, light-gray and grayish-pink, 

medium-grained, very dolomitic and 

Cumulative 

thickness 

(feet) 

272 

262 

257 

resistant, irregularly bedded________ 5. 5 219 

16. Dolomite, calcitic ; mottled grayish-pink 

(5R 8/2), pale-red (5R 6/2), and 

light-gray (N 7), very fine grained; 

contains a scattering of detrital angular quartz grains as much as 0.15 mm 

in diameter ; weathers grayish orange pink. (II56-23Q) __________________ 12 

15. Sandstone, pale-red (5R 6/2, poorly 

sorted, fine- to medium-grained; 

grains are as much as 0.5 mm in diameter ; larger grains, rounded to subrounded ; irregularly bedded. ( Il56-

213.5 

229) ------------------------------ 1.5 201.5 

14. Dolomite, mottled light-gray and grayish-pink, very fine grained; one bed__ 3 200 

13. Covered ---------------------------- 15 197 

Aphanitic dolomite unit: 

12. Dolomite, slightly calcitic, light-gray 

(N 7), subaphanitic to very fine 

grained ; contains· tiny veinlets and 

vugs filled with crystalline dolomite; 

contains sparsely scattered detrital 

quartz grains, angular ; mostly grains 

are smaller than 0.3 mm in diameter ; 

medium-bedded; weathers light gray. 

(II56-228) ------------------------- 5 182· 

11. Qo.vered______________________________ 32 177 

10. Dolomite, calcitic, mottled grayish-pink 

(5R 8/2) and pale-red (5R 6/2) ; 

consists mostly of idiomorphic very 

fine to fine dolomite crystals; contains scattered clusters of mediumsized dolomite crystals and much interstitial calcite. (II56-227) ------- 15 145 

9. Covered-------------·---------------- 17 130 
148 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 33.-Upper Sycamore Oan.yo~Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

8. Limestone, dolomitic, pinkish-gray 

( 5Y R 8/1) ; lower part very fine 

grained; very silty and sandy ; contains detrital quartz grains as large 

as 1 mm in diameter ; all larger grains 

are subrounded and highly shattered; 

grades upward into aphanitic dolomite containing irregularly scattered 

detrital quartz grains as much as 0.5 

mm in diameter ; larger grains are 

angular; contains irregular layers of 

dark-gray chert and small spherical 

chert pebbles having brown rinds; 

thin-bedded (beds are as much as 1 

Sub-

'Unit 

thickness 

(feet) 

ft thick) ; weathers pinkish gray. 

(H5~226, 225) -------------------- 26 

7. Dolomite, light brownish-gray (5YR 

6/1), aphanitic ; conchoidal fracture ; 

contains scattered clasts of slightly 

darker and denser aphanitic dolomite, and contains sparsely scattered 

detrital quartz grains as much as 

0.07 mm in diameter; weathers grayish orange. (H5~224) ------------ 13 

6. Sandstone, quartzitic, very light gray 

(N 8) to medium light gray (N 6), 

v.ery fine grained to medium-grained; 

consists of tightly packed angular 

quartz grains and contains no cement ; contains some angular pebbles 

composed of aphanitic dolomite; 

slightly variable in thickness; weathers light to pale brown. (H5~223) _ 1 

Fetid dolomite unit: 

5. Dolomite, light brownish-gvay (5YR 

6/1), very finely crystalline, finely 

laminated, somewhat porous; fetid 

odor ; contains lenses of gray chert 

throughout subunit, as much as 1 ft 

in length, weathers yellowish gray. 

(H5~222) ----------------------- 8 

Beckers Butte Member: 

4. Sandstone, pale-red, poorly sorted, fineto ooarse-grained; thin-bedded; contains 

red.Jtinted sandy ·shale partings:; s·lopeforming ----------------------------- 12 

3. Sandstone, pale-red (5R 6/2), pooTly 

sorted, generally fine- to mediumgrained; contains a few coarse grains; 

smaller groins are angular to subangular ; large grains are generally subangular ; consists of 20 perc·ent calcitic 

cement; scattered quartzite cobbles ; 

crops out as one massive bed; weathers~ 

pale brown. (H~221)_______________ 5 

2. Conglomerate consisting of rounded 

cobbles of red-weathering quartzite 

averaging 4 in. in length (maximum of 

8 in.) ; poorly eemented by red-'tinted 

sandy clay matrix ; very soft, ehanneled 

into the underlying subunit___________ 8 

Cumulative 

thickness 

(feet) 

113 

87 

74 

73 

65 

53 

48 

SECTION 33.-Uppm· Sycamore Oanyo~Continued 

Martin Formation-Continued 

Beckers Butte Member-Continued 

1. Sandstone, yellowish-gray (5Y 8/1) to light 

'brownish-gray (5YR 6/1) to grayish-red 

( 5R 4/2) in upper part, coarse-grained; 

contains quartz grains, which are angular and tightlY, packed and interlocked; 

becomes very coarse grained in upper 

part; most quartz grains are shattered; 

very thickbedded (beds are 3-6 ft 

thick) ; subunit shows much current 

bedding; contains scattered quartz and 

quartzite pebbles, which are rounded and 

ais much as 10 mm in diameter throughSubunit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

out subunit. (H5~220, 219) ----------- 40 40 

Base of section not exposed. 

SECTION 34.-Tonto Natural Bridge 

[Narrow canyon rising directly southeast of Natural Bridge (Pine 

quadrangle, NW*NE:i4 sec. 8, T. 11 N., R. 9 E.). Photograph lots 

AK 3113, 3114. Measured by Curt Teichert, 1956] 

Martin Thrma tion 

Jerome Member: 

Upper unit (top eroded) : 

43. Dolomite, slightly calcitic, very sandy, 

light brownish-gray (5YR -6/1) to 

light olive-gray ( 5Y 6/1) ; consists of 

a fine-grained crystal aggregate containing some interstitial calcium 

carbonate; contaiilJS -detrital quartz 

grains ranging in rsize from silt to 

more thian 0.75 mm in diameter, 

making up not more than 5 percent 

of the rock ; larger grains. are well 

rounded; 3 ft below top, calcitic crinoid stems occur in pockets ; mediumSub-

'Unit 

thickness 

(feet) 

to thick-bedded; weathers moderate 

brown. ( T5~502, 501) ------------ 22 

4. Dolomite, slightly calcitic, pale-red 

( 5R 6/2) , very fine grained, thinly 

lamina ted ; contains a small amount 

of detrital quartz grains ranging in 

size from silt to about 1 mm in diamelter; quartz grains are peripherally repl·aced by calcium carbonate, 

some are highly replaced ; thinbedded ; weathers light brown. 

( T~500) -------------------------- 25 

41. Dolomite, calcitic, grayish orange-pink 

(5YR 7/2), medium- to coarsegrained, saccharoidal ; consists of a 

tightly packed aggregate of idiomorphic and hypidiomorphic dolomite 

crystals and some interstitial calcitic 

matter; contains scattered detrital 

quartz grains of silt and fine-sand 

size constituting less than 1 percent 

of rock; microstylolites present; 

medium-bedded; weathers medium 

light gray. (T5~99) ------------- 7 

40. Sandstone, dolomitic, similar to subunit 38---------------------------- 5 

Cumulative 

thickness 

(feet) 

389 

367 

342 

335 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 149 

SECTION 34.-Tonto Natural Bridge-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

39. Limestone, medium light-gray (N 6), 

very fine grained, microscopic calcarenitic texture; contains a few indistinct fragments of microfossils ; contains much detrital quartz, unsorted, 

ranging in grain size from silt to almost 1 mm in diameter, which makes 

Subunit 

thickness 

(feet) 

up as much as 20 percent of rock 

mass; fine grains and larger are subrounded to rounded; weathers light 

brown. (T56-498)_________________ 2 

38. 'Sandstone, dolomitic, grayish orangepink (5R 8/2) ; consists of an unsorted aggregate of detrital quartz 

grains ranging in size from silt to 

about 0.5 mm in diameter; larger 

grains are generally subrounded to 

rounded ; grains are embedded in carbonate matrix that seems to be a 

slightly calcitic dolomite; it is very 

fine grained; bedding is irregularly 

thin to thick ; contains some crossbedding. ( T56-497) --------------- 14 

37. Dolomite, slightly -calcitic, grayish orange-pink (5YR 7/2) ; consists of a 

coarse grained aggregate composed 

mostly of idiomorphic dolomite crystals and some interstitial calcitic matter ; crystals are concentrically laminated; contains scattered detrital 

quartz grains. generally of silt size, 

totaling less than 1 percent of rock 

mass ; upper 3 ft contains large 

( 3 in.) spherical cavities filled 

with white calcite; thick-bedded; 

weathers medium gray to medium 

dark gray_________________________ 24 

36. Covered interval. ( T56-496) _________ 7 

35. Dolomite, pinkish-gray, very fine 

grained, laminated, poorly exposed__ 3 

34. Dolomite, calcitic, pinkish-gray (5YR 

8/1) ; consists of a fine grained matrix 

having a calcarenitic texture in 

places ; contains abundant detrital 

quartz grains ranging in size from silt 

Cumulative 

thickness 

(feet) 

330 

328 

314 

290 

'283 

to about 0.5 mm in diameter; larger 

grains are generally subrounded to 

rounded ; gl'!ains make up as much as 

about 7 percent of rock; small calcite 

vugs are abundant; subunit is medium-bedded. (T56-495) ----------- 10.5 280 

33. Sandstone, light-gray, medium-grained, 

quartzose, thin bedded, very weathered and poorly exposed ___________ _ 

32. Dolomite, slightly calcitic, sandy, palered ( 5R 6/2) ; groundmass is a medium- to coarse-grained aggregate 

composed of idiomorphic to hypidiomorphic dolomite crystals and some 

2 269.5 

SECT:J;ON 34.-71onto Natural Bridge-Continued 

Martin Formation-Continued 

J erQme Member-Continued 

Upper unit-Continued 

32. Dolomite, etc.-Continued 

interstitial calcitic material; contains varying amounts of detrital 

quartz grains ranging in size from silt 

to about 0.5 mm in diameter; grains 

mostly angular to subangular, but 

some of the larger grains are well 

rounded; detrital quartz constitutes 

Subunit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

as much as 5 percent of the rock ; 

unbedded; weathers pale gray. 

( T56-494) --------------·----------- 2 267.5 

31. Sandstone, pinkish-gray ( 5Y R 8/1), 

fine- to medium-grained; consists of 

a tightly packed aggregate of subangular quartz grains ranging in size 

from silt to about 0.6 mm in diameter ; contains very little calcareous 

cement ; crossbedded ; thick-bedded; 

weathers light brown. (T56-493) __ 4.5 265.5 

30. Dolomite, slightly calcitic, pale redpurple (5RP 6/2) to grayish-red (lOR 

4/2) , fine-grained ; lowermost 1 ft is 

very sandy and contains detrital 

quartz grains ranging in size from silt 

to about 0.5 mm in diameter; the 

grains are subangular to subrounded 

and make up as much as 20 percent 

of the rock mass ; upper part darker 

and finer grained containing a small 

amount of silt-size quartz detritus 

only; has a massive appearance and 

no well-formed beds; weathers yellowish gray. (T56-492) ------------ 5 

29. Dolomite, pale red-purple (5RP 6/2), 

fine- to medium-grained, saccharoidal; consists of an aggregate of 

idiomorphic and hypidiomorphic dolomite crystals and some interstitial 

calcium carbonate; contains no detrital quartz; thick-bedded; weathers 

light brownish gray to yellowish 

brown. (T56-491)_________________ 2 

28. Sandstone, grayish orange-pink ( 5Y R 

7/2), poorly sorted; medium- to 

coarse-grained, but contains many 

quartz particles as small as silt ; all 

grains, even most of larger ones, are 

angular to subangular ; in places, 

grains are tightly packed, in others, 

much calcareous cement occurs; 

many grains are peripherally replaced by calcite; thin-bedded ; 

weathers light brown. (T56--490) __ 5 

27. Covered interval_____________________ 15 

26. Dolomite, pale-red, medium-grained, 

saccharoidal; appears to be thickbedded with many interspersed 

thinner beds (beds are 2 in. to 2 

ft thick) ; weathers purplish gray__ 12 

261 

256 

254 

249 

234 
150 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 34.-Tonto Natuml Bridg·e-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

25. Dolomite, very slightly 

red (5R 6/2), very 

calcitic, palefine to finegrained, saccharoidal ; contains a 

considerable amount of detrital 

quartz grains-mostly silt size, some 

grains as much as 0.25 mm in 

diameter-all grains are angular ; 

total detrital quartz constitutes less 

than 5 percent of the rock; mediU1llbedded; poorly exposed; weathers 

Sub-

'll nit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

light brown. ( T56-489) ----------- 7 222 

24. Covered interval_____________________ 10 215 

23. Dolomite, medium light-gray, very fine 

grained, medium-bedded; weathers 

light gray-------------------------

22. Dolomite, slightly calcitic, grayishpink ( 5R 8/2), very fine grained; 

contains abundant detrital quartz, 

mostly of silt size, but some grains 

are very fine; detrital quartz makes 

up as much as 10-15 percent of the 

rock; thick-bedded; weathers light 

brown. (T56-488) ----··------------

21. Limestone, medium light-gray ( N 6), 

mottled grayish-pink (5R 8/2) ; consists of a dense calcareous matrix 

containing many small idiomorphic 

dolomite crystals, abundant authigenic doubly terminated quartz 

crystals, and calcispheres and ostracode shells ; mottling caused by veins 

and stringers of coarsely crystalline 

pink calcite; generally thick bedded 

(beds are 11h-2 ft thick ; some beds 

are thinner), weathers light brown. 

8 205 

5.5 197 

(T56-487) _________________________ 14.5 191.5 

20. Dolomite, calcitic, pale-red (5R 6/2), 

fine-grained, saccharoidal; contains 

very little very fine detrital quartz 

grains; thin-bedded; weathers pale 

red. (T56-486)____________________ 9 177 

19. Limestone, dolomitic ; mottled pinkishgray (5YR 8/1) to grayish-pink (5R 

8/2) to pale-red (5R 6/2), more moderately pink ( 5R 7 /4) in upper part, 

fine-grained and silty to sandy in 

lower part, medium-grained and more 

sandy in upper part ; detrital quartz 

grains in lower part range in size 

from silt to about 0.3 mm in diameter; 

grains are angular and make up no 

more than 10 percent of rock ; in upper part quartz grains are 0.5mm and 

less and are mixed angular to well 

rounded ; many grains are peripherally replaced by limestone or dolomite 

and make up as much as 25 percent of 

rock; lower part laminated; thickbedded throughout (beds are 2-4 ft 

thick) ; weathers yellowish gray. 

(T56-485, 484) --------------------- 23 168 

SECTION 34.-Tonto Natuml Bridge-Continued 

Martin Formation-Continued 

J erqme Member-Continued 

Upper unit-Continued 

18. Sandstone, grayish orange-pink (5YR 

7/2), very fine to fine-grained; consists of detrital quartz grains ranging in size from silt to about 0.3 mm 

in diameter; forms a tightly interlocking mosaic containing a small amount 

of dolomitic limest·one cement ; ,. thinbedded to :fiaggy; weathers grayish 

orange. ( T56-482) ----------------

17. Dolomite, calcitic, mottled grayishpink (5R 8/2) and light-gray (N 7), 

very fine grained to aphanitic; seems 

to be generally laminated, although 

laminations are not seen everywhere; 

thick-bedded ; weathers light brown. 

( T56-481) __ ------------------------

16. Dolomite, mottled grayish-pink ( 5R 8/ 

2) and pale-red ( 5R 6/2), very fine to 

fine-grained; contains no detrital material ; irregularly bedded ; weathers 

pale red. (T56-480) ______________ _ 

15. Limestone, mottled light-gray (N 7) and 

pinkish-gray (5YR 8/1), aphanitic; 

subconchoidal fracture; calcarenitic 

texture; contains rounded limestone pebbles generally less than 1 

mm in diameter; slightly laminated; 

thick-bedded; weathers light gray. (T56-479) ________________________ _ 

14. Dolomite, grayish-pink (5R 8/2), very 

fine grained; consists of an aggregate 

of dolomite crystals generally less 

than 0.05 mm in size and a few angular detrital quartz grains as much as 

0.25 mm in diameter; thick-bedded 

(beds are 1-3 ft thick) ; weathers 

grayish pink. (T56-478) -----------

13. Dolomite, pale-red (5R 6/2), very 

fine grained, sandy; matrix consists 

of a very fine aggregate of dolomite 

crystals less than 0.1 mm in diameter; contains abundant detrital 

quartz grains ranging in size from 

silt to 0.5 mm in diameter ; conta~ns 

scattered pebbles as much as 2 mm 

in diameter, making up as much as 

percent of the rock ; all quartz grains 

are angular to subangular, the largest 

grains also are poorly rounded; massive, unbedded; weathers pale red. 

(T56-477)-------------------------

12. Dolomite breccia, composed mostly of 

boulder-sized fragments of two types 

of dolomite : (1) pale-red, medium- to 

coarse-grained, saccharoidal; and (2) 

light-gray to medium light-gray, finegrained to dense dolomite _________ _ 

11. Dolomite, pale-red, fine-grained, saccharoidal, thin-bedded, poorly exposed------------------------------

Sub-

'Unit 

thickness 

(feet) 

6 

9 

7 

2 

4 

Cumulative 

thickness 

(feet) 

145 

139 

130 

123 

121 

7 117 

9 110 

6.5 101 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 

SECTION 34.-Tonto Natural Bridge-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit : 

Sub-

'unit 

thickness 

(feet) 

10. Limestone, light brownish-gray 5Y R 

6/1) ; mottled pale-olive (lOY 6/2); 

matrix aphanitic, containing scattered idiomorphic dolomite crystals 

and very few detrital quartz grains of 

silt size that account for much less 

than 1 percent of the rock; contains 

a very fine debris composed of ostracode fragments ; has many small calcite vugs and stringers ; thick-bedded 

(beds are 1-1% ft thick) ; weathers 

grayish orange. ( T5~ 76) ________ _ 

9. Limestone, pale-red (5R 6/2) ; matrix 

dense, containing a few small idiomorphic dolomite crystals not more 

than 0.2 mm in diameter and much 

detrital quartz, most from silt size 

to about 0.5 mm in diameter but 

some grains as much as 2 mm; all except the largest grains are angular 

to subangular; the distribution of 

quartz grains is very uneven ; the 

grains tend to accumulate in sandy 

layers where they make up 30-40 

percent of the rock. The limestone 

matrix contains numerous ostracode 

shells and fragments ; length of the 

shells is generally less than 0.5 mm ; 

they are not identifiable as to genus 

or species. Thin-bedded to flaggy ; 

some layers tend to be shaly ; wea th2.5 

ers olive gray. (T5~75) ----------- 5 

8. Limestone, mottled grayish orangepink (5YR 7/2) and grayish-pink 

(5R 8/2) ; matrix composed of dense 

limestone, numerous idiomorphic dolomite crystals, as much as 0.25 mm 

in diameter, and many small calcite 

stringers randomly orientated ; contains abundant detrital quartz grains 

ranging in size from silt to about 

1 mm in diameter and making up as 

much as 10 percent of the rocks; individual grains are angular to subangular, except for the largest, which 

may be subrounded ; contains a few 

scattered calcispheres; medium-bedded (beds are 8-10 in. thick) ; weathers light brown. (TW--474) -------- 2 

7. Limestone, slightly dolomitic, pale~red 

(5R 6/2 to lOR 6/2), medium grained, 

very sandy; matrix formed of crystalline aggregate; detrital quartz abundant, making up as much as 25 percent of rock ; individual quartz grains 

range in size from fine to medium, 

and are generally angular to subangular; lower 3 ft contains quartzite 

pebbles as much as 1 in. in diameter; 

thick-bedded (beds are 2-4ft thick) ; 

Cumulative 

thickness 

(feet) 

94.5 

92 

87 

SECTION 34.-Tonto Natural Bridge-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

7. Limestone, etc.-Conti.lnued 

weathers yellowish to purplish gray. 

Sub-

'Unit 

thickness 

(feet) 

(T56-473) __________________________ 11 

6. Sandstone, yellowish-gray ( 5Y 8/1), 

fine- to medium-grained; mosaic composed of tightly packed detrital quartz 

grains, which are angular to subangular-rarely subrounded-and range 

from 0.05 to 0.5 mm in diameter ; 

contains a small amount of calcareous 

matrix; very thick bedded (beds are 

2-3 ft thick) ; weathers pale to light 

brown. (T56-472) ----------------- 20 

5. Dolomite, pale-red (5R 6/2), in places 

mottled grayish-orange (lOYR 7/4), 

dense, very sandy; detrital quartz 

grains very unevenly distributed, in 

places constituting as much as 20 percent of the rock; grains very unsorted 

and range in size from silt to 1.5 mm 

in diameter; all except the largest 

grains are angular and .even the largest grains are poorly rounded ; upper 

1-1% ft contains quartzite boulders 

as much as 5 in. long and 2 in. thick 

and stringers of quartz sandstone ; 

grades abruptly into subunit 6; thickbedded (beds are about 2 ft thick) ; 

weathers pale red to light brown. 

(T56-471) -------------------------- 8 

4. Sandstone, pale-red (lOR 6/2), finegrained appearance; dolomitic matrix 

in places constitutes as much as 40 

percent of the rock; contains detrital 

quartz grains, which are unsorted, 

angular to subangular, and range in 

size from silt to fine; some grains are 

as much as 0.5 mm, and even the 

larger grains are poorly rounded; 

lamination seen on weathered surfaces; above 5 ft. patches of angular 

pebbles of medium- to olive-gray finegrained to dense dolomite occur, forming pockets of intraformational conglomerate; top 3 ft is conglomeratic 

and contains quartzite pebbles as 

much as 2 in. in diameter; in places 

poorly defined bedding planes 4-6 in. 

apart occur ; the subunit is generally 

massive; weathers brownish gray. 

(T56-470, 469)-------------------- 15 

3. Dolomite, pale-red (lOR 6/2), very fine 

grained, laminated ; contains a few 

angular silty to fine quartz grains 

that at no place constitute as much as 

1 percent of the rock; somewhat 

porous, the pores are rarely larger 

than 1 mm and are arranged along 

certain laminae; the subunit is characterized by many intraformational 

151 

Cumulative 

thickness 

(feet) 

85 

74 

54 

46 
152 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 34.-Tonto Natural Bridge-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

3. Dolomite, etc.-Continued 

disconformities resulting in lateral 

gradation from thin-bedded (bed are 

1h in. thick) to very massive rock ; 

weathers grayish orange. (T56-

468)-------------------------------

2. Dolomite, varying shades of pale red 

( 5R 6/2 to lOR 6/2) ; consists of an 

aphanitic ground mass containing 

irregularly scattered detrital quartz 

grains ranging in size from silt to 0.5 

rum in diameter, which are generally 

angular to subangular and more 

rarely subrounded ; part of the rock 

is free from quartz detritus, in other 

parts, it may constitute as much as 

3 percent of rock; vugs are as much 

as 10 rum in diameter and are lined 

with crystalline dolomite and filled 

with calcite; also contains some large 

calcite drusen; in parts, laminated 

with alternating red- and gray-tinted 

bands; contains closely spaced microstylolites ; in lower part, some pockets 

Sub-

'Unit 

thickness 

(feet) 

18 

of more sandy dolomite, intraformational conglomerate, and small dolo~ 

mite pebbles occur; medium-bedded; 

weathers reddish to yellowish gray. 

(T56-467, 466)-------------------- 9 

1. Conglomerate, reddish-brown; matrix 

composed of coarse-grained calcar~ 

ous sandstone containing large angular to poorly rounded pebbles and 

boulders of Mazatzal Quartzite as 

much as 10 in. in diameter and, 

generally, smaller pebbles of Red 

Rock Rhyolite as much as 2 in. in 

diameter; thick-bedded_____________ 4 

Precambrian: Red Rock Rhyolite of Wilson (1939). 

SECTION 35.-Pinal Creek 

OumuZative 

thickness 

(feet) 

31 

13 

4 

[West bank of Pinal Creek, 3lh miles northwest of Globe (Globe quadrangle, NW:JASE:JA sec. 10, T. 1 N., R. 15 E.). Photograph lots AK 

1783, 1784. Measured by Curt Teichert, 1953 and 1956. This section was not sampled lithologically, and the following descriptions are 

from field notes only] 

Martin Formation: 

Jerome Member: 

Upper unit: 

26. Siltstone, dolomitic, yellowish-brown __ 

25. Shale, light-brown to yellowish-brown, poorly exposed ____________________ _ 

24. Siltstone, dolomitic, partly sandy, massive; rich in Atrypa, Theodossia, 

and other brachiopods. Mostly of 

the Atrypas are bivalved and lie 

parallel to the bedding, but some are 

at right angles to bedding planes. 

Subspherical quartz concretions occur locallY-------------------------

Subunit 

thickness 

(feet) 

18 

31 

17 

Oumulative 

thickness 

(feet) 

262 

244 

213 

SEcTION 34.-Tonto Natural Bridge-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

23. Siltstone, dolomitic, fissile, light-brown 

contains a fossiliferous chert band, 

2 in. thick, at 9 ft.; in upper part, 

elongated chert lenses, 4-5 in. thick, 

occur, some fusing into continuous 

layers _____________________________ _ 

Sub-

'unit 

thickness 

(feet) 

15 

22. Alternating limestone and dolomitic siltstone in beds about 1 ft. thick. Limestone : dark, full of brachiopod fragments. Siltstone; light brown______ 6 

21. Siltstone, dolomitic, grading into silty 

dolomite, light-gray to light-brown ; 

fissility formed by weathering; richly 

fossiliferous at 15-16 ft. and contains one 4-in. calcarenite band_____ 19 

20. Siltstone, dolomitic; has interbeds of 

shaly siltstone containing brachiopods----------------~-------------- 4 

19. Dolomite, light brownish-gray, finely 

crystalline ; contains silicified corals 

and brachiopods___________________ 8 

18. Limestone, medium- to dark-gray, medium-crystalline, sandy, thick-bedded 

(beds are as much as 3 ft. thick) ; 

silicified brachiopods occur in lower 3 

ft; remainder of subunit is rich in 

fossil fragments-------------------- 8 

17. Sandstone, very fine grained, thinbedded to fiaggy ; contains small-scale 

crossbedding ; lower 1-2 ft quartzitic_ 4 

16. Mostly covered interval ; some shaly 

siltstone in upper 8 ft_______________ 21 

15. Sandstone, very fine grained__________ 1 

14. Dolomite, brownish-gray, very finely 

crystalline ___________ .______________ 1 

13. Limestone, medium-gray, medium- crystalline to coarsely crystalline, generally crinoidal; contains some brachiopod fragments______________________ 4 

12. Sandstone, light grayish-brown, mediumbedded, fine-grained, laminated, crossbedded--------------··-------------- 2 

11. Shale, silty, dolomitic, light-brown; contains some light-brown to gray dolomitic siltstone______________________ 12 

10. Dolomite, very silty, medium-gray, medium-crystalline to finely crystalline; 

nodular; contains partings of siltstone; cliff-forming ________________ _ 

9. Dolomitic, medium-gray, finely crystalline, laminated; the uppermost 6-in. 

layer has a very irregular lower bedding plane ________________________ _ 

8. Sandstone, silty, dolomitic, light-gray, 

medium-bedded, crossbedded ______ _ 

7. Siltstone, argillaceous, soft_ __________ _ 

6. Sandstone, calcareous, brown, thickbedded; contains invertebrate fossils on bedding planes _________________ _ 

16 

2 

3 

1 

10 

Oumulative 

thickness 

(feet) 

196 

181 

175 

156 

152 

144 

136 

132 

111 

110 

109 

105 

103 

91 

75 

73 

70' 

69 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 153 

SECTION 35.-Pinal Greek-Continued 

Martin lforma tion-Continued 

Jerome Member-Continued 

Upper unit: 

5. Dolomite, gray, finely to medium- crystalline, mottled ____________________ _ 

Sub1unit 

thickness 

(feet) 

4. Dolomite, yellowish-gray, very finely 

crystalline, slightly calcitic, arenaceous______________________________ 16 

3. Dolomite, light-gray, aphanitic, thickbedded; lower 2ft is platy__________ 14 

2. Dolomite, generally light-gray to yellowish-gray, aphanitic, thick- to medium-bedded ; contains some layers of 

sandy dolomite____________________ 19. 5 

1. Dolomite, gray, aphanitic, thick-bedded_ 6. 5 

Base of section not exposed. 

SEeTON 36.-Theodore Roosevelt Da;m 

Cumulative 

thickness 

(feet) 

59 

56 

40 

26 

6.5 

[East of Theodore Roosevelt Dam (Roosevelt quadrangle, sec. 29, T. 4 

N., R. 12 E.). Photograph lots AK 2811, 2812. Measured by R. L. 

Harbour, 1956] 

Martin Formation : Sub- CumuJ erome Member : t~7~t ~~~~~~ 

Upper unit: (j;;:) t}::~) 

41. Sandstone, brownish-gray (5YR 5/1), finegrained, hard; grains angular to subangular; contains an appreciable amount of 

calcareous cement; invertebrate tracks 

abundant throughout ; uppermost 5 ft. 

coarser grained and contains gray limestone fragments ; thin-bedded ; weathers 

light olive gray. (H56-99) ------------ 25 486 

40. Shale, gray with greenish tint; very poorly exposed ______________________________ 35 461 

39. Dolomite, mottled pale-red (lOR 6j2), grayish-orange (10YR 7 j4), and pale-brown 

( 5Y R 5/2), very finely crystalline; contains a considerable amount (as much as 

10 percent) of very fine grained detrital 

quartz ; has one resistant bed; weathers 

light brown. (H56-98) --------------- 5 426 

38. Sandstone, light-brown, well-sorted, coarsegrained, thin-bedded; forms dark resistant cap to underlying light-colored cliffforming subunit______________________ 5 421 

37. Sandstone, grayish orange-pink (lOR 8/2), 

very fine grained ; contains much calcareous cement and silt and some larger angular to subangular grains as much as 

0.3 mm diameter, laminated; cliff-forming; weathers pinkish gray. (H56-97) _ 4 416 

36. Dolomite, medium-gray, thin-bedded, poorly 

exposed ----------------------------- 4 412 

35. Sandstone, gray, conglomeratic, consists of 

well-sorted rounded grains containing 

scattered granules as much as 3 mm in 

diameter ----------------------------- 4 408 

34. Dolomite, light-gray, medium-crystalline; 

consists of abundant coarse sand grains 

near base; crinoidal; crops out in two resistant beds separated by 3 in. of gray 

argillaceous dolomite__________________ 3 404 

SECTION 36.-Theodore Roosevelt Dam.-Continued 

Martin Formation-Continued ~;:i~- 1~~:; 

Jerome Member-Continued thick- thickUpper unit-Continued {;::~) t}~!~) 

33. Dolomite, light brownish-gray (5YR 6/1), 

very finely crystalline ; subconchoidal 

fracture; contains less than 1 percent 

silt-size to very fine-grained detrital 

quartz ; in basal 1 ft., quartz grains as 

much as 1 mm in diameter occur; contains scattered calcite vugs; thickbedded 

(beds. are 2% ft. thick) ; highly jointed 

and forms slopes; weathers light brown. 

(H56-96) --------------·--------------- 10 

32. Dolomite, calcitic, pale red-purple (5RP 

6/2), finely crystalline; contains small 

vugs as much as 5 nun in diameter filled 

with baryte( ?) and a small amount of 

silt-size and very fine grained detrital 

quartz ; has a few large sand grains and, 

in places, abundant nonsilicified crinoid 

stems ; forms not more than two beds ; 

401 

weathers grayish orange pink. (H56-95) 7 391 

31. Dolomite, very sandy, pale-red (lOR 6/2), 

finely crystalline; contains much siltand fine-sand sized detrital quartz ; 

grades locally into dolomitic sandstone ; 

crops out in two thick beds, which are 

finely crossbedded; contains scattered 

impressions of fish plates on bedding 

surface ; weathers light brown. ( H56-

94) -----------------------·------------ 10 384 

30. Dolomite, very slightly calcitic, grayish 

orange-pink ( 5YR 7/2), very finely to 

finely crystalline; contains scattered detrital quartz grains which compose as 

much as about 3 perc-ent of the rock and 

are as much as 0.5 nun in diameter and 

subrounded ; some brachiopods occur 

near base of unit; forms one massive 

bed (the subunit is the most prominent 

cliff former in entire section) ; weathers dark yellowish orange. ( H56-91, 

92, 93)------------------------------- 17 374 

29. Dolomite, light gray, finely crystalline; 

sandy; contains abundant partially silicified brachiopods; crops out in three beds_ 6 357 

28. Sandstone, very dolomitic, grayish orangepink ( 5 Y R 7/2) ; has a very finely crystalline carbonate matrix which is slightly 

calcitic and contains detrital quartz 

grains ranging in size from silt to very 

fin-e ; grades into sandy dolomite in 

places; very thinly laminated, crossbedded ; weathers grayish orange. 

(H56-90)----------------------------- 2 351 

27. Dolomite, light-gray, saccharoidal, medimn-bedded (beds are 1 ft. thick)------ 5 349 

26. Dolomite, yellowish-gray ( 5 Y 7/2) , very 

finely crystalline; contains abundant 

silicified brachiopods------------------ 2 344 
154 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 36.-Theodore RooswDelt Dam-Continued 

Martin Formation-Continued Sub- Oumuunit lative 

Jerome Member-Continued thick- thick- ness ness Upper unit-Continued (feet) (feet) 

25. Dolomite, pale yellowish-brown (10YR 

6/2) with small pale-red patches, very 

finely to finely crystalline ; contains a 

small amount (less than 1 percent) of 

detrital quartz grains ranging in size 

from silt to very fine; thin-bedded (beds 

are less than 18 in. thick) ; weathers 

pale yellowish brown. ( H56-89) ______ 5 342 

24. Dolomite, pale yellowish-brown (10YR 

6/2), medium-crystalline; contains calcite-filled cavities as much as 1.5 em in 

diameter; contains poorly preserved 

silicified brachiopod fragments. ( H56-

88) -------------------·---------------- 1 337 

23. Dolomite, medium-gray, ve.ry finely to 

medium crystalline; contains brachiopod 

and crinoid fragments (not silicified) ; 

thin-bedded____________________________ 2 336 

22. Dolomite, slightly calcitic, pale yellowishbrown (lOY R 6/2), finely to mediumcrystalline; evenly distributed silt-size 

detrital quartz constituting as much as 

3 percent of the rock ; thin-bedded ; beds 

are interlayered by gray shale; basal 

dolomite beds contain crinoid columnals 

as much as 12 mm in diameter ; slopeforming; weathers pale yellowish brown. 

(H56-87) _____________________________ 19 334 

21. Dolomite, slightly calcitic, light olive-gray 

(5Y 6/1) to yellowish-gray (5Y 7/2), 

very fine grained, very thin bedded 

(thickest bed is 6 in.) ; interbedded with 

grayish-brown, and light-brown shale; 

slope-forming. ( H56-85, 86) ---------- 24 315 

20. Sandstone, light-brown, fine- to coarsegrained; contains much dolomitic cement and many calcite-filled solution 

cavities; cliff-forming; weathers yellowish brown_____________________________ 5 291 

19. Sandstone, very pale-orange (lOYR 8/2) 

to grayish-orange (10YR 7/4) ; consists 

of a poorly sorted aggregate of angular 

to subangular detrital coarse to very 

coarse quartz grains and some pebbles 

as much as 5 mm in diameter ; crops out 

as two beds of equal thickness ; 

weathers grayish orange. (H56-84) ___ 6 286 

18. Dolomite, pale yellowish-brown (10YR 

6/2), very uniformly and finely crystalline; contains an insignificant amount of 

silt-size detrital quartz; thin-bedded and 

contains interbedded shaly layers ; slopeforming. ( H56-83) -------------------- 11 280 

17. Dolomite, pale yellowish-brown (lOYR 

6/2) ; consists of a subaphanitic dolomitic matrix containing abundant idiomorphic dolomite crystals about 0.1 mm in 

diameter and some rounded fragments of 

denser dolomite as much as 0.8 mm in 

diameter; contains as much as 10 perSECTION 36.-Theodore Roosevelt Dam-Continued 

Martin Formation-Continued 

J erQme Member-Continued 

Upper unit-Continued 

Sub- Oumuunit lative 

thick- thick17. Dolomite, etc.-Continued 

cent mostly very :fine detrital quartz 

grains, and some subrounded grains as 

much as 0.5 mm in diameter ; contains one 

cliff-forming crossbedded bed; weathers 

ness ness (feet) (feet) 

grayish orange. (H56-82) ------------ 4 269 

16. Covered -------------------------------- 1 265 

15. Sandstone, grayish orange-pink (5YR 7/2) 

and grayish-orange (10YR 7/4), poorly 

sorted, very :fine to medium-grained, consists of as much as 50 percent dolomitic 

matrix; larger quartz grains are generally subrounded; matrix is subaphanitic ; crops out in two conspicuously crossbedded beds; cliff-forming; weathers 

grayish orange. ( H56-80, 81) --------- 18 264 

14. Covered -------------------------------- 4 246 

13. Sandstone, yellowish-gray (5Y 8/1) to light 

brown (5YR 6/4), has limonitic stains; 

medium to coarse grained, poorly sorted; 

grains are angular to subrounded, tightly 

packed; quartzitic texture; contains a 

small quantity of chert fragments, no 

matrix; medium-bedded beds are 2 ft 

thick ; contains interbedded layers of 

grayish-green shale; current-bedded; 

poorly exposed. (H56-79) ------------ 19 242 

Aphanitic dolomite unit : 

12. Dolomite, mostly light brownish-gray 

(5YR 6/1) to light olive-gray (5Y 6/1); 

some beds are medium dark gray (N 4), 

generally aphanitic, grades into very 

:finely crystalline dolomite in about the 

uppermost 20 ft ; basal 20 ft contains 

detrital quartz becoming less abundant 

upward from a maximum of about 10 percent near base; quartz grains are poorly 

sorted, generally angular to subangular, 

in sizes as large as 0.5 mm ; also, restricted to basal 15 ft is an admixture 

of small angular fragments of dolomite 

as much as 0.3 mm in diameter and of 

scattered feldspar crystals, some of 

which are larger than 2 mm in diameter; 

subunit is regularly thin bedded, (beds 

average somewhat less than 1ft in thickness) separated by grayish-green shale 

layers containing many invertebrate 

trails; weathers in various shades of orange and yellowish brown. ( H56-71-

78) ----------------------·------------- 88 223 

11. Dolomite, medium light-gray (N 6) to 

medium-gray (N 5), subaphanitic; in 

lower part, matrix consists of irregularly 

convoluted layers and fragments of more 

or less transparent dolomite (visible in 

thin section) and grades upward into 

almost aphanitic dolomite containing 

very scattered silt-size detrital quartz 

grains; medium- and light-gray chert 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 155 

SECTION 36.-Theodore Roose'l)elt Dam-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

11. Dolomite, etc.-Continued 

Sub- Cumuunit Zative 

thick- thickness ness (feet) (feet) 

occurs in lenses and small nodules having 

brown rinds; medium-bedded; weathers 

light olive gray. (H56-69) ----------- 14 135 

Fetid dolomite unit: 

10. Dolomite, pale-brown (5YR 5/2) to pale 

yellowish-brown (lOYR 6/2), finely crystalline, laminated; emits a very weak 

fetid odor ; lower part contains numerous 

small calcite-filled cavities; throughout 

subunit, mottled dark-gray and white 

chert lenses as long as 1 ft. and fine distributed chert occur. (H56-67, 68) ___ 20 121 

Beckers Butte Member : 

9. Dolomite and shale, interbedded in l-in. thick 

beds. Shale, medium gray. Dolomite, reddish-gray, very fine grained_______________ 3 101 

8. Sandstone and shale, thinly interbedded. 

Sandstone: light-gray, clean, and composed 

of a mixture of coarse and very fine quartz 

sand. Shale: sandy, micaceous, grayishred to grayish-olive_______________________ 8 98 

[Subunits 1-7 fill a steep-walled channel in Troy Quartzite and Mescal 

Limestone] 

7. Sandstone, mottled light brownish-gray (5Y 

8/1), very arkosic, poorly sorted-fine to 

very coarse grained-contains individual 

quartz and feldspar grains as much as 8 mm 

in diameter; all quartz grains are badly shattered and broken and angular to subangular ; 

forms smoothly rounded cliff having conspicuous crossbedding; weathers brownish 

gray. (H56-66)_________________________ 10 90 

6. Sandstone, yellowish-gray ( 5Y 8/1), very arkosic; contains feldspar grains as much as 

3.5 mm in diameter; quartz grains are tightly interlocked, subangular to angular, and 

fine- to coarse-grained; contains some pebbles as large as 10 mm; contains scattered 

angular black chert fragments as much as 

7 mm in diameter; contains thick, crossbedded layers separated by thin layers of 

greenish micaceous shale; cliff-forming. 

(H56-64, 65)---------------------------- 20 80 

5. Shale, grayish-green, sandy, micaceous; pooTly exposed------------------------------- 1 60 

4. Sandstone, pinkish-gray (5YR 8/1) to yellowgray ( 5Y 8/1), poorly sorted, fine- to coarsegrained ; contains scattered quartz grains as 

much as 5 mm in diameter, generally ranging from angular to subrounded, and having a considerable amount of overgrowth 

and some etching; medium-bedded (beds are 

172 ft thick) ; current-bedded; invertebrate trails occur on top of subunit; weathers yellowish gray. (H56-63) ------------ 13 59 

3. Sandstone, medium-gray with pale-red streaks, 

finely lamina ted ; generally fine grained, 

but contains quartz pebbles as much as 6 

mm in diameter__________________________ 6 46 

SECTION 36.-Theodore Roosevelt Dam-Continued 

Sub- Cumuunit Zative 

Martin Formation-Continued thick- thickBeckers Butte Member-Continued (j;;:) <i::~) 

2. Conglomerate, medium-gray, current-bedded; 

contains rounded quartz pebbles as much as 

1 in. in diameter; one bed_________________ 5 40 

1. Sandstone, pale red-purple (5RP 6/2) to grayish red-purple (5RP 4/2) ; fine-grained, laminated, crossbedded; consists of angular to 

subangular quartz grains which are tightly 

packed; basal 10 ft contains weathered 

boulders of siltstone and limestone ; medium-bedded. (H56-62) ----------------- 35 35 

Precambrian: Troy Quartzite and Mescal Limestone. 

SECTION 37.-Windy Hill 

[East and southeast slope of Windy Hill, a promontory on the south side 

of Roosevelt Reservoir (Roosevelt quadrangle, sec. 24, T. 4 N., R. 

12 E.). Photograph lots AK 2812, 2813. Measured by R. L. Harbour, 1956 ; additional observations by Curt Teichert, 1957] 

Martin Formation: 

Jerome Member: 

Upper unit: 

27. Dolomite, pale-red, very fine grained, 

resistant, unbedded _______________ _ 

Sub-

'll nit 

thickness 

(feet) 

5 

26. Dolomite, pale-red, fine-grained, silty, 

slope-forming; weathers into nodules_ 7 

25. Sandstone, medium light-gray, finegrained, quartzitic, thin-bedded (beds 

are 1-6 in. thick)------------------- 16 

24. Shale, bluish-gray, poorly exposed; contains laminated medium gray chert 

lenses and layers as much as 3 in. 

thick, some of which contain brachiopod fragments. (H56-36l) _______ 36 

23. Dolomite, mottled pale-red (lOR 6/2) 

and grayish-red ( 5R 4/2), calcitic, 

fine-grained; contains abundant detrital quartz grains ranging in size from 

silt to 0.3 mm in diameter ; contains 

brachiopod remains and, more rarely, fish plates. (H56-360) ---------- 2 

22. Dolomite, mottled pale-red (lOR 6/2) 

and light-brown (5YR 6/4), very calcitic, fine- to medium-crystalline; 

contains abundant detrital quartz, 

patchily distributed, that forms 10-

50 percent of the rock; containing 

dolomite clasts of granule size and 

crinoid stem fragments as much as 

1.5 mm in diameter; lower 2 ft 

poorly bedded, resistant; bulk of subunit shows crossbedding and is cliff 

forming; upper 3 ft finer grained, 

fissile; weathers grayish orange 

pink. (H56-359)------------------ 25 

21. Dolomite, grayish orange-pink (5YR 

7/2), fine- to medium-crystalline; 

contains abundant (as much as 15 

percent) detrital quartz in silt and 

very fine sand size and scattered 

rounded larger grains as much as 

Cumulative 

thickness 

(feet) 

382+ 

377+ 

370+ 

354+ 

318+ 

316+ 
156 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 37.-Windy Hill-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

21. Dolomite, etc.-Continued 

0.5 mm in diameter ; lower half 

easily eroded, upper half more resistant; indistinctly bedded; weathSub-

'Unit 

thickness 

(feet) 

ers light brown. (H56-358) ------- 16 

20. Dolomite, broadly mottled pale-red 

(lOR 6/2) and grayish-orange 

(10YR 7/4) speckled with dark gray 

(N 3), fine- to medium-crystalline; 

contains abundant (as much as 15 

percent) poorly sorted detrital 

quartz ranging in grain size from 

silt to rounded as much as 1 mm in 

diameter ; most larger grains are 

superficially etched; weathers pale 

red. (H56-357) -------------------- 13 

19. Sandstone, medium light-gray, finegrained, finely cross-laminated______ 5 

18. Dolomite, pale-red (lOR 6/2), mediumto coarse-crystalline, finely laminated; contains scattered detrital 

quartz of silt size and a few rounded 

grains as much as 1 mm in diameter; 

contains very small crinoid plates 

and fragments of fish plates; weathers pale red. (H56-356) ___________ 18 

17. Sandstone, pinkish-gray ( 5Y R 8/1), 

very fine grained to silty; cement is 

composed of slightly calcitic dolomite ; most quartz grains are about 

0.06 mm in diameter, angular; cliff 

forming ; weathers yellowish gray. 

(H56-355) -----------·-------------- 10 

16. Dolomite, mottled medium light-gray 

and pale-red, thin-bedded___________ 5 

15. Dolomite, mottled medium light-gray 

and pale-red; contains partially silicified brachiopod fragments; has one 

laminated resistant bed_____________ 5 

14. Dolomite, medium light-gray, very finely 

crystalline, thin-bedded_____________ 3 

13. Dolomite, medium light-gray, very finely 

crystalline; contains crinoid stems 

and brachiopod remains; mediumbedded (beds are 1 ft. thick) . ( H56-

354)_______________________________ 3 

12. Dolomite, light olive-gray (5Y 6/1) ; 

lower half finely crystalline ; upper 

half medium crystalline, containing 

an admixture of detrital quartz (as 

much as 10 percent) in silt and very 

fine sand size ; thin-bedded, containing 

shaly partings; slope-forming; weathers yellowish gray. ( H56-352, 353) __ 39 

11. Sandstone, very pale orange (lOYR 

8/2) ; has much dolomitic cement. 

Evidence of lamination occurs on 

weathered surface. Contains quartz 

grains ranging in size from silt to fine 

sand, angular to subangular ; grades 

Cumulative 

thickness 

(feet) 

291+ 

275+ 

262+ 

257+ 

239+ 

229+ 

224+ 

219+ 

216+ 

213+ 

SECTION 37.-Windy Hill-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

11. Sandstone, etc.-Continued 

upward into very sandy mediumSub-

'unit 

thickness 

(feet) 

grained saccharoidal dolomite, finely 

laminated; thin-bedded, containing 

partings of green-tinted shale and 

many invertebrate trails on bedding 

planes; weathers yellowish gray. 

(H56-350, 351)-------------------- 30 

10. Sandstone, medium light-gray, coarsegrained, crossbedded ; grains subrounded, having etched surfaces ; has 

dolomitic matrix ; basal 3 ft is cliff 

forming____________________________ 14 

9. Sandstone, grayish-pink ( 5R 8/2), very 

fine to medium-grained, has as much 

much as 50 percent dolomitic matrix; 

quartz grains range in size from silt 

to 0.5 mm in diameter and are angular to subangular, rarely subrounded; 

thin-bedded, contains shaly partings 

near base ; upper half finely crossbedded ; weathers grayish orange 

pink. (H56-349) ------------------- 26 

8. Sandstone, light-brown (5YR 6/4) to 

grayish orange-pink (5YR 7/2), indistinctly laminated, fine- to mediumgrained ; similar to subunit 5 but has 

less well sorted aggregate of fine to 

medium quartz grains, subangular to 

subrounded, containing moderate proportion of dark minerals (hornblende 

and others) ; weathers pale yellowish 

brown. (H56-348) _________________ 26 

Aphanitic dolomite unit : 

7. Dolomite, mottled pale-red (lOR 6/2) 

and light brownish-gray ( 5Y R 6/1), 

aphanitic ; conchoidal fracture ; 

groundmass pelletal to finely clastic ; 

medium-bedded (beds are less than 

1 ft thick) having shaly partings between dolomite beds; weathers light 

brown. (H56-347)_________________ 10 

6. Covered______________________________ 5 

5. Sandstone, grayish orange-pink (lOR 

8/2) to yellowish-gray (5Y 8/1), finegrained, indistinctly laminated ; composed of an aggregate of tightly interlocked subangular quartz grains ; contains sprinkling of glauconite grains; 

weathers light yellowish brown. 

(H56-346)--------------------------- 4 

4. Dolomite, pale-red (5R 6/2) with grayish-red stains, aphanitic; conchoidal 

fracture; contains aphanitic dolomite 

clasts as much as 0.7 mm in diameter and small calcite vugs (as much 

as 1 mm in diameter) having 

irregular outlines; weathers grayish 

orange. (H56-345) --·-------------- 24 

Cumulative 

thickness 

(feet) 

174+ 

144+ 

130+ 

104+ 

78+ 

68+ 

63+ 

59+ 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 

SECTION 37.-Windy Hill-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

3. Dolomite, medium-gray (N 5) to medium light-gray (N 6), aphanitic; conchoidal fracture; laminated. In 

upper part of subunit, rock contains 

angular clasts of aphanitic dolomite 

in an aphanitic groundmass and angular to subangular detrital quartz 

grains, some having etched surfaces 

as much as 0.5 mm in diameter. 

Subunit contains dolomite beds approximately 1-ft thick separated by 

3-in. beds of gray shale and lenses 

Subunit 

thickness 

(feet) 

of gray chert; weathers light brown. 

(H56-343, 344)-------------------- 25 

2. Dolomite, medium-gray, slightly mottled and laminated; contains flat 

chert nodules as much as 10 in. long 

OumuZative 

thickness 

(feet) 

35+ 

and 4 in. thick_____________________ 8 10+ 

1. Dolomite, pale-red (5R 6/2) to grayishred (lOR 4/2) and medium-gray (N 

5), aphanitic, very finely laminated; 

contains scattered detrital quartz 

grains, in places, in thin layers and 

lenses; grains !lre angular, as much 

as 0.3 mm in diameter ; contains 

scattered small and flat chert pebbles 

having brown rinds; weathers yellowish gray. (T57-444) ------------ 2+ 2+ 

Base not exposed. 

SECTION 38.-Limestone Hills 

[Upper part of escarpment facing East Verde River about 2 miles southeast of junction of Verde and East Verde Rivers (Turret Peak quadrangle, sec. 28, T. 11 N., R. 7 E., unsurveyed). Photograph lots AK 

3109, 3110. Measured by Curt Teichert and R. L. Harbour, 1956] 

Martin Formation : Sub- Oumuunit Zative 

Jerome Member : thick- thickUpper unit (top of section not exposed) : 

34. Dolomite, light-gray ( N 7) , finely crystalline; contains a large number of 

silicified brachiopods ( Oamarotoechia 

ness 

(feet) 

sp., Oranaena? sp.) and some corals 

(Breviphyllum sp., Hemagonaria .sp.) 

occurring in loose rocks; contains 

very little rounded detrital quartz 

grains as much as 0.3 mm in diameter; weathers yellowish gray. 

(H56-341)_________________________ 9 

33. Covered (possibly underlain by thinbedded dolomite)------------------ 32 

32. Dolomite, pale-red, finely crystalline; 

constitutes one resistant bed; weathers into rounded blocks_____________ 2 

31. Dolomite, medium-gray, finely crystalline; constitutes one resistant bed___ 3 

30. Dolomite, medium-gray, finely crystalline, thin-bedded, slope-forming_____ 2 

ness 

(feet) 

480 

471 

439 

437 

434 

SECTION 38.-Limestone Hills-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

29. Dolomite, grayish-pink ( 5R 8/2), finely 

crystalline; contains much detrital 

quartz (as much as 50 percent) locally concentrated in thin beds. 

( H56-340) -----------·--------------

28. Dolomite, light brownish-gray (5YR 

6/1) , very finely to finely crystalline ; 

contains a large amount (as much as 

50 percent) of detrital quartz, generally unsorted, ranging in grain size 

from silt to well-rounded, grains 

have peripheral etching; at 32-33 ft 

is a breccia bed; medium- to thickbedded (maxim urn bed thickness, 4 

ft) ; weathers light brown. (H56-

Subunit 

thickness 

(feet) 

3 

338, 339, 339A)-------------------- 46 

27. Dolomite, light-gray (N 7) with palered streaks, very fine grained ; contains a large amount of detrital 

quartz (as much as 50 percent), unsorted, ranging in grain size from 

silt to well-rounded as much as 

0.5 mm in diameter ; larger grains 

have some peripheral etching; thinbedded; weathers grayish orange 

pink. (H56-337) ------------------ 7 

26. Dolomite, light-gray (N 7), uniformly 

very fine grained ; constitutes one 

cliff-forming bed. (H56-336) ------- 10 

25. Dolomite, light brownish-gray (5YR 

6/1) ; has a very fine grained ground 

mass containing streaks of aphanitic 

dolomite; contains much detrital 

quartz, unsorted, ranging in grain 

size from silt to 0.5 mm in diameter ; 

larger grains, rounded to subrounded; thin-bedded ; weathers yellowish 

gray. ( H56-335) ------------------ 6 

24. Dolomite, pale-red, saccharoidal; constitutes one cliff-forming bed containing ?Thamnopora and stromatoporoids ---------------------------- 9 

23. Dolomite, light brownish-gray (5YR 

6/1), very finely crystalline; contains 

scattered detrital quartz sand, ranging in grain size mostly from silt to 

very fine, containing a few rounded 

grains as much as 0.6 mm in diameter ; basal 4 ft form one bed ; remainder of subunit, thin bedded; 

weathers pale brown. (H56-334)___ 9 

22. Dolomite, slightly calcitic, pale-red 

(lOR 6/2) to pinkish-gray (5YR 8/1), 

finely to very finely crystalline ; contains varying amounts (as much as 50 

percent) of detrital quartz sand ranging in grain size from silt to very fine 

laminated; thin-bedded; weathers 

grayish orange pink. ( H56-332., 

333) ------------------------------ 28 

157 

OumuZative 

thickness 

(feet) 

432 

429 

383 

376 

366 

360 

351 

342 
158 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 38.-Limestone Hills-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

21. Limestone, dolomitic, light brownishgray (5YR 6/1) ; fine crystalline; rock 

divided into areas 1 em or more in 

diameter in which all crystals have 

identical or similar optical orientation; contains large amounts (as 

much as 10 percent) of detrital generally angular quartz grains 0.2 mm 

or less in diameter ; contains a few 

fish plates near base of unit; slightly 

laminated; thin-bedded; weathers 

pale yellowish brown. ( H56-331) __ _ 

20. Dolomite, medium-gray, sandy; contains some calcareous brachiopod fragments at base _________________ _ 

19. Siltstone, yellowish-gray, fissile, slope- forming ____________________________ _ 

18. Limestone, medium light-gray (N 6) 

to light brownish-gray ( 5Y R 6/1) ; 

has aphanitic matrix; contains 

some small idiomorphic dolomite 

crystals and small amount of detrital 

quartz; contains coquinalike assemblage of brachiopods ( spiriferid ?, 

Atrypa?) ; contains also echinoid 

.;fragments and ostracodes; weathers 

light brown. (H56-330) ------------

17. Siltstone, yellowish-gray, fissile _____ _ 

16. Covered (some thin-bedded saccharoiSubunit 

thickness 

(feet) 

9 

1 

OumuZative 

thickness 

(feet) 

314 

305 

6.5 304 

0.5 297.5 

1 297 

dal dolomite found on slope)------- 34 

Aphanitic dolomite unit: 

296 

15. Dolomite, light-gray, aphanitic ______ _ 

14. Dolomite, medium-gray (N 5), very 

finely crystalline, slightly calcitic, 

laminated; has very weak fetid odor; 

contains some light- to medium-gray 

chert 1 ft above base of subunit. 

(H56-329) ________________________ _ 

13. Dolomite, light brownish-gray ( 5Y R 

6/1), aphanitic; conchoida~ fracture; 

contains scattered detrital quartz 

sand, mostly silt size to very fine; 

contains a few rounded to subrounded grains as much as 0.7 mm 

in diameter and also clasts of darker 

aphanitic dolomite that are wellrounded and as much as 0.6 mm in 

diameter ; contains scattered small 

spherical chert pebbles; weathers 

3 262 

9 259 

yellowish gray. (H56-328) ________ 12 250 

12. Dolomite, pinkish-gray (5YR 8/1) and 

light olive-gray (5Y 6/1), aphanitic; 

conchoidal fracture; lower part contains 1-2 percent detrital quartz of 

silt size; upper part contains no 

detrital quartz and very small calcite vugs ; faintly pelletal or clotty 

texture of dolomite recognizable in 

upper part; medium bedded (beds are 

1-2 ft thick) ; weathers yellowish 

gray. (H56-326, 327) -------------- 19 238 

SECTION 38.-Limestone Hills-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

11. Covered _____________________________ _ 

10. Dolomite, light-gray (N 7), medium 

light-gray (N 6), and light brownishgray (5YR 6/1), aphanitic; conchoidal fracture ; contains varying 

amounts (as much as 1 percent) of 

detrital quartz grains as much as 1 

mm in diameter, although most are 

smaller ; grains more than 0.3 mm are 

generally well rounded to subrounded ; medium-bedded (beds are 2 

Subunit 

thickness 

(feet) 

48 

ft thick) ; weathers yellowish gray. 

(H56-322, 323, 324, 325)------------ 52 

9. Dolomite, banded pale red purple ( 5RP 

6/2) and grayish red (5R 4/2), aphanitic, finely laminated; contains a 

scattering of detrital quartz grains as 

much as 0.2 mm in diameter; thinbedded (beds are 6 in. thick) and contain partings of greenish-gray shale 

less than 1 in. thick between dolomite 

beds; contains lenses of gray chert 

that distort the lamination; weathers 

grayish pink. (H56-318) ---------- 12 

Fetid dolomite unit: 

8. Dolomite, medium-gray (N 5), very 

finely crystalline ; contains layers of 

reworked chert granules and pebbles 

and some detrital quartz grains as 

much as 0.2 mm in diameter; weathers 

light olive gray. (H56-317) -------- 2 

7. Dolomite, light brownish-gray (5YR 

6/1) ; fetid odor; finely crystalline ; 

contains large numbers of idiomorphic dolomite crystals ranging in size 

from 0.05 to 0.15 mm; finely laminated, lamination caused by finely dispersed organic matter; has considerable megascopic and microscopic 

porosity, amounting in places to over 

10 percent ; upper 3 ft contains lenses 

of banded orange to very light gray 

and light-gray chert; weathers grayish orange pink. (H56-320, 321) ____ 19 

Beckers Butte Member : 

6. Covered -------------------------------- 8 

5. Sandstone, mottled pale-red ( 5R 6/2) and 

grayish orange-pink (5YR 7/2), very 

poorly sorted; contains grains as much 

as 2 mm in diameter ; smaller grains 

generally angular ; grains 1 mm and more 

in diameter subrounded to angular ; contains small amounts of cement composed 

of slightly calcitic dolomite ; thin-bedded ; 

contains partings of red-tinted shale. 

(H56-319)____________________________ 14 

4. Covered________________________________ 4 

3. Sandstone, light-brown to pale-brown, 

coarse-grained; contains conglomeratic 

layers; thick-bedded; crossbedded; top 

of subunit poorly exposed______________ 45 

OumuZative 

thickness 

(feet) 

219 

171 

119 

107 

105 

86 

78 

64 

60 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 

SECTION 38.-Limestone Hills-Continued 

Subunit 

Martin Formation-Continued thickness Beckers Butte Member-Continued (feet) 

2. Conglomerate, light-brown; contains pebbles of igneous rock and quartzite as 

much as 6 in. in diameter; thick-bedded__ 8 

1. Conglomerate, mottled light brown (5YR 

6/4) and pale-brown (5YR 5/2) ; contains pebbles of igneous rocks and quartzite as much as 6 in. in diameter; grades 

upward into coarse-grained sandstone, 

poorly sorted ; contains angular to subrounded quartz grains and a considerable 

amount of calcareous cement; thickCumulative 

thickness 

(feet) 

15 

bedded; weathers grayish brown_______ 7 7 

Precambrian : diabase ( ? ) 

SECTION 39.-0hasm Oreek 

[2.5-3 miles upstream from junction Chasm Creek and Verde River (Turret Peak quadrangle, probably on border of sees. 5 and 8, T. 12 N., 

R. 5 E., unsurveyed). Photograph lots AK 3012, 3013. Measured 

by Curt Teichert and R. L. Harbour, 1956] 

Martin Formation: Subunit Jerome Member : thickUpper unit (top not exposed) : (j;;:) 

24. Dolomite, light-gray (N 7) to light 

brownish-gray (5YR 6/1), finely crystalline; laminated by layers of detrital quartz grains ranging in size 

from very fine to fine; thick-bedded 

(beds are 1-3 ft. thick) ; weathers 

yellowish gray ; forms vertical cliff of 

which only the lowermost 8 ft. could 

be examined. (H56-267) ---------- 25 

23. Dolomite, mottled grayish orange-pink 

(5YR 7/2) and medium dark-gray 

(N 4), finely crystalline to mediumcrystalline, thick-bedded; weathers 

grayish orange. (H56-266) ------- 7 

22. Dolomite, yellowish-gray, finely crystalline; lower half rich in poorly preserved brachiopod fragments; thickbedded ; very hard, cliff-forming; 

weathers yellowish brown. ( H56- 269) _______________________________ 15 

21. Covered (probably underlain by fossiliferous dolomite)------------------ 16 

20. Dolomite, light-gray (N 7), finely crystalline; contains abundant broken 

brachiopod shells and some gastropods; medium-bedded; weathers yellowish gray ; poorly exposed. ( H56-

270)_______________________________ 15 

19. Dolomite, pale yellowish-brown (10YR 

6/2), very finely crystalline; subconchoidal fracture ; argillaceous, medium-bedded; weathers yellowish 

gray. (H56-265)__________________ 3 

18. Dolomite, light brownish-gray ( 5Y R 

6/1) to light olive-gray (5Y 6/1) ; extremely varied lithology; basal 1 ft. 

laminated and brecciated; remainder 

of subunit partly aphanitic, mottled, 

Cumulative 

thickness 

(feet) 

305+ 

280+ 

273+ 

258+ 

242+ 

227+ 

SECTION 39.-0hasm Greek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

18. Dolomite, etc.-Continued 

and laminated, partly finely crystalline, darker in color, and cherty; 

forms upper part of cliff, base of 

which is formed by subunit 17; weathers yellowish brown. ( H5-263, 264) _ 

Aphanitic dolomite unit: 

17. Dolomite, light-gray (N 7) ; variable 

lithology; aphanitic to finely crystalline; upper 2 ft laminated; some 

vuggy porosity occurs ; contains a few 

scattered chert fragments in uppermost foot; scattered detrital quartz 

grains ranging in size from silt to 

very fine; thick-bedded; cliff-forming; weathers yellowish gray. (H56-

262)---------------~---------------

Subunit 

thickness 

(feet) 

9 

7 

16. Covered______________________________ 12 

15. Dolomite, light brownish-gray (5YR 

6/1) , very finely crystalline to subaphanitic; contain some vuggy porosity; thick-bedded (beds are 2-2% 

ft thick) ; massive, cliff-forming; 

weathers yellowish gray. (H56-261) 8 

14. Dolomite, grayish orange-pink (5YR 

7/2), aphanitic; conchoidal fracture; 

has micropelletal structure and dense 

pattern of small vugs filled with calcite; contains scattered layers having 

vuggy porosity ; has a few chert impregnations and chert fragments; 

entire subunit massive, having few 

signs of bedding. (H56-260) ------ 15 

13. Covered------------------------··----- 8 

12. Dolomite, yellowish-gray ( 5Y 7/2) , 

aphanitic ; subconchoidal fracture ; 

clastic, consisting mostly of rounded 

dolomite clasts ranging in size from 

very small to 2 mm in diameter ; contains scattered small chert "clouds"; 

medium-bedded; weathers yellowish 

gray. (H56-259) -------------------- 6 

11. Dolomite lithologically like variety 

1 of subunit 10-------------------- 13 

10. Dolomite, alternating layers of (1) pale 

red-purple (5RP 6/2) dolomite, which 

is aphanitic, has a conchoidal fracture, is argillaceous, contains scattered detrital quartz ranging in size 

from silt to 0.3 mm in diameter, and 

weathers yellowish gray; and (2) 

mottled light brownish gray ( 5Y R 

6/1) and medium gray (N 5) dolomite, which is aphanitic, has a conchoidal fracture, contains no detrital 

quartz, and has small cherty and calcite vugs, the chert in which is probably authigenic. Entire subunit is 

medium bedded, weathers yellowish 

gray. (H56-257, 258)-------------- 11 

159 

Cumulative 

thickness 

(feet) 

224+ 

215+ 

208+ 

196+ 

188+ 

173+ 

159+ 

146+ 
160 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 39.-Chasm Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

9. Dolomite, banded medium gray (N 5) 

and medium light gray (N 6), aphanitic; subconchoidal fracture; laminated; contains some thin chert bands 

at intervals; in some parts, has mircobreccia structures ; other parts are 

sandy, containing poorly sorted detrital quartz making up more than 50 

percent of rock; quartz grains are as 

much as 1 mm in diameter, subanguSubunit 

thickness 

(feet) 

lar to sub rounded, and have some 

peripheral etching; medium- to thickbedded (beds are 4 in. to 2 ft thick) ; 

weathers yellowish gray. (H56-2·55, 

256)------------------------------- 37 

8. Covered______________________________ 12 

7. Dolomite, medium-gray (N 5), aphanitic; conchoidal fracture; has scattered layers containing small chert 

pebbles having limonitic rinds; lower 

3 ft, thin bedded ; upper 3 ft, medium- to thick-bedded; weathers light 

olive gray. (H56-254) ------------- 6 

Fetid dolomite unit : 

6. Dolomite, medium-gray (N 5), very fine 

grained, very finely lamina ted ; in 

places small-scale slump structures 

and brecciation occur; uppermost 3 

ft has many thin layers of chert parallel to lamination; medium-bedded 

(beds are 10 in. to 2 ft thick) ; weathers pale yellowish brown. ( H56-

252,253)--------------------------- 20 

5. Dolomite, light brownish-gray (5YR 

6/1), very fine grained, thinly laminated in places; has faintly fetid 

odor; locally contains some poorly 

sorted detrital quartz, of which the 

rounded shattered grains are as much 

as 0.8 mm in diameter; thin-bedded to 

flaggy; weathers light brownish gray. 

(H56-251)------------------------- 5 

4. Dolomite, lower 3 ft alternating light 

brownish gray (5YR 6/1) and grayish 

red (5R 4/2) ; remainder of unit light 

brownish gray with grayish red mottling ; very fine grained ; argillaceous ; 

scattered detrital quartz (1 percent or 

less) ranging in grain size from silt; 

to very fine thin-bedded to flaggy and 

fissile ; near top several layers of mottled gray and grayish-red shale occur; weathers light olive gray. 

(H56-250)------------------------- 15 

Beckers Butte(?) Member: 

3. Dolomite, grayish-red (lOR 4/2), very 

finely crystalline, silty; contains a 

considerable amount of unsorted detrital quartz ranging in size from silt 

grains to rounded shattered grains as 

Cumulative 

thickness 

(feet) 

135+ 

98+ 

86+ 

80+ 

60+ 

55+ 

SECTION 39.-Chasm Creek-Continued 

Martin Formation-Continued Sub- Oumuunit lative 

Beckers Butte ( ? ) Member-Continued 

3. Dolomite, etc.-Continued 

thick- thick- ness neBs 

(feet) (feet) 

much as 0.5 mm in diameter; thinbedded; weathers pale red. (H56-

249)-------------------------------

2. Sandstone, dolomitic, grayish-red (lOR 

4/2) ; changes laterally into sandy 

dolomite; poorly sorted, containing 

angular grains ranging in size from 

very fine to medium, and a scattering 

of rounded highly shattered grains as 

much as 1 mm in diameter; thickbedded (beds are about 2 ft thick) ; 

weathers yellowish brown. ( H56-

248) ______________________________ _ 

1. Sandstone, yellowish-gray ( 5 Y 8/1), 

mostly medium-grained; composed of 

tightly packed angular to subangular 

grains of quartz. Many individual 

"beds are conglomeratic, containing 

pebbles of red-tinted quartzite and 

granite as much as % inch in diameter ; some beds are crossbedded. 

Medium- to thick-bedded; weathers 

light olive gray. (H56-245, 246, 

3 40+ 

5 37+ 

247) ---------------------··-- ------- 32+ 32+ 

Base not exposed. 

SECTION 40.-Squau; Peak mine 

[On northeastern slope of Squaw Peak, above Squaw Peak mine, about 

6 miles south of Camp Verde (Turret Peak quadrangle, center sec. 31, 

T. 13 N., R. 5 E.). Photograph lots AK 3091, 3002. Measured by 

Curt Teichert, 1953] 

Martin Formation: 

Sub- Oumuunit Zative 

thick- thickness ne88 Jerome Member : 

Aphanitic dolomite unit 

eroded) : 

(feet) (feet) 

(top of section 

7. Dolomite, medium-gray, finely crystalline; contains scattered detrital 

quartz; has brecciated zone at base; 

thick-bedded; poorly exposed. (TL365) ------------------------------- 5+ 63+ 

6. Sandstone, light-gray, quartzitic, medium-grained__________________________ 1 58 

5. Dolomite, medium-gray, aphanitic; has 

brecciated zone at top______________ 2 57 

Fetid dolomite unit: 

4. Dolomite, slightly calcitic, medium-gray 

to light olive-gray ( 5 Y 6/1) . Lower 

part finely crystalline, laminated ; 

upper part very finely crystalline, 

having considerable vuggy porosity. 

Has slightly fetid odor; thickbedded; poorly exposed; weathers yellowish gray. (TL-364) ------------- 14 55 

Beckers Butte (?) Member : 

3. Sandstone, streaky grayish-pink (5R 8/2) 

and grayish orange-pink (lOR 8/2), 

medium- to coarse-grained; contains 

rounded to subrounded quartz grains 

embedded in a considerable amount of 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 161 

SECTION 40.-.Squaw Peak mine-Continued 

Martin Formation-Continued ~~ft 

Beckers Butte ( ? ) Member-Continued t~!~!-

3. Sandstone, etc.-Continued (feet) 

dolomitic matrix; medium-bedded ; 

weathers light brown. (TL-363) ------ 7 

2. Sandstone, pale-red (5R 6/2), very poorly 

sorted; contains quartz grains as much 

as 1.5 mm in diameter, generally subrounded; contains a considerable 

amount of dolomitic matrix; partly 

grades into sandy dolomitic rock; weathers light brown. (TL-362) ------------ 1 

1. Sandstone, arkosic, pinkish-gray (5YR 8/1) 

to yellowish-gray ( 5Y 8/1), very coarse 

grained to conglomera tic. Basal part 

contains subangular quartz pebbles as 

much as 1 em in diameter and angular 

feldspar pieces as much as 7 mm in diameter. Thick-bedded (beds are 2-3 ft 

thick) ; highly crossbedded throughout; 

weathers light brown. (TL-361) ------- 33 

Precambrian: Granite. 

SECTION 41.--J erCYme 

Cumulative 

thickness 

(feet) 

41 

34 

33 

[Small canyon in slope 1.1 miles northeast of Jerome and 0.3-0.4 mile 

southeast of Hopewell (Clarkdale quadrangle, sec. 14, T. 16 N., 

R. 2 E., unsurveyed). Photograph lots AK 2361, 2362. Measured by 

Curt Teichert and R. L. Harbour, 1956 ; additional observations by 

Teichert, 19571 

Martin Formation: 

Jerome Member : 

Upper unit: 

40. Dolomite, light-gray, aphanitic, thinbedded, poorly exposed ___________ _ 

39. Limestone, dolomitic, very sandy, pinkish-gray (5YR 8/1) ; has fine-grained 

carbonate matrix containing unsorted 

detrital quartz grains ranging in size 

from silt to 0. 7 mm ; larger grains 

are generally subrounded, highly 

etched; finely porous; mediumSub- Cumuunit lative 

thick- thick- ness ness (feet) (feet) 

3 491 

bedded; cliff-forming. (T56--550)___ 4 488 

38. Dolomite, pinkish-gray (5YR 8/1), 

medium-grained, saccharoidal; similar to subunits 30, 32, 34, and 36; 

interbedded with several smaller 

subunits of almost aphanitic whiteweathering dolomite________________ 22 484 

37. Dolomite, pinkish-gray (5YR 8/1) to 

light brownish-gray ( 5Y R 6/1), very 

nne grained, laminated, somewhat 

brecciated; contains scattered chert 

fragments and quartz grains ranging in size from silt to medium; 

weathers light gray. ( T56--549) ____ 2. 5 462 

36. Dolomite, slightly calcareous, light 

brownish -gray ( 5 Y R 6/1) , generally 

medium-grained, saccharoidal; contains some layers of dense calcareous 

dolomite containing abundant detrital quartz grains as much as 1 mm 

in diameter, subrounded to wellrounded. Dolomite replaces some silSEcTION 41.--Jerome-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

36. Dolomite, etc.-Continued 

ica. Similar in outcrop appearance 

Subunit 

thickness 

(feet) 

to subunits 30 and 32; weathers light 

brown. ( T56--548) ---------------- 37 

35. Dolomite, pinkish-gray ( 5Y R 8/1), 

medium-grained; consists of idiomorphic to hypidiomorphic dolomite 

crystals. Upper part very porous and 

contains calcite-filled vugs as much 

as 5 in. in diameter; upper 5 ft contains abundant poorly recrystallized 

Amphipora. Hard, cliff-forming; 

weathers grayish orange pink. (T56-

546, 547)-------------------------- 11 

34. Dolomite, grayish orange-pink (5YR 

7/2), medium-grained; consists of 

idiomorphic to hypidiomorphic dolomite crystals; similar to subunit 32 

but less porous ; contains some small 

crinoid debris ; unbedded ; breaks up 

into small rounded fragments; weathers light brown. ( T56-545) _______ 38 

33. Dolomite, pale-red (5R 6/2) to pale-red 

( 5RP 8/2) , very fine grained, hard, 

bank-forming; contains much fine silicified crinoid debris ; weathers yelCumulative 

thickness 

(feet) 

459.5 

422.5 

411.5 

lowish gray. (T56-544)___________ 1. 5 373.5 

32. Dolomite, pinkish-gray (5YR 8/1), fineto medium-grained; composed of 

hypidiomorphic to allomorphic dolomite crystals ; generally porous, containing some large cavities as much 

as lh in. in diameter; thick-bedded ; 

upper 2-3ft are shaly; weathers dull 

gray. (T56--543)__________________ 7.5 372 

31. Dolomite, pale red-purpe (5RP 6/2), 

fine-grained ; contains irregular chert 

"clouds" and irregularly shaped chert 

particles ; rich in silicified corals 

(?Tabulophyllum sp., cyathophylloid 

and amplexoid corals) ; hard, cliffforming, highly jointed; weathers 

light gray. (T56--542) ------------- 1. 5 364. 5 

30. Dolomite, grayish-pink (5R 8/2) to 

pinkish-gray ( 5Y R 8/1), very fine 

grained, silty and argillaceous; contains detrital quartz silt constituting 

as much as 15 percent of rock; poorly 

formed bedding; upper 2-3 ft is 

shaly; weathers pinkish gray. (T56- 541) _______________________________ 14 363 

29. Dolomite, light-gray (N 7) to light 

brownish-gray ( 5Y R 6/1) ; composed 

of an aggregate of very fine- to medium-grained hypidiomorphic and allotriomorphic dolomite crystals; contains a sparse sprinkling of rounded 

detrital generally fine quartz grains ; 

thin-bedded ; slope-forming; slightly 

porous; weathers light olive gray. 

(H56--316) ------------------------ 21 349 
162 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 41.--J erome-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

28. Dolomite, light olive-gray (5Y 6/1), 

Subunit 

thickness 

(feet) 

medium-grained, saccharoidal; consists of idiomorphic to hypidiomorphic dolomite crystals; thin-bedded; 

weathers yellowish gray. ( H56-

315)------------------------------- 4 

27. Dolomite, grayish-pink (5R 8/2), very 

fine grained to subaphanitic; rich in 

detrital quartz grains making up as 

much as 20 percent of rock; grains 

range is size from silt size to 1 mm 

in diameter; nearly all grains except 

smallest ones, are subrounded to 

rounded and have etched surfaces; 

thinly laminated, thin-bedded; weathers pinkish gray. (H56-314) _______ 5 

26. Dolomite, light brownish-gray (5YR 

6/1) to medium-gray (N 5), very fine 

grained to subaphanitic; contains 

ghosts of either pellets or microfossils; laminated, thin-bedded (beds. 

are less than 1 ft thick) ; weathers 

yellowish gray to light olive gray. 

(H56-312, 313)-------------------- 23 

25. Dolomite, medium-gray, fine-grained, 

friable_____________________________ 2 

24.. Dolomite, light bl'ownish-gray ( 5YR 

6/1) and pinkish-gray (5YR 8/1) and 

yellowish-gray ( 5Y 8/1) mottles, subaphanitic, faintly laminated; contains "clouds" of somewhat darker 

material (probably clay?) ; mediumbedded (beds are less than 1 ft 

thick) ; weathers yellowish gray. 

(H56-311)------------------------- 12 

23. Covered interval--------------------- 2 

22. Dolomite, light-gray (N 7), very fine 

grained, thick-bedded (beds are 2lh 

ft thick) ; scattered small fish plates 

occur in lower part. (H56-309, 310) _ 12 

21. Dolomite, medium-gray, mottled lightgray and olive-gray, finely crystalline------------------------------- 7 

20. Dolomite, medium light-gray (N 6) to 

medium-gray (N 5), very fine grained, 

thinly laminated; contains abundant 

ghosts of microfossils (ostracodes?, 

calcispheres?) ; thin-bedded; weathers yellowish gray (H56-308) ------ 12 

19. Dolomite, light-gray (N 7) with some 

pale-red stains, very fine grained to 

subaphanitic, thinly laminated ; contains very scattered quartz silt 

grains; weathers white to yellowish 

gray. (H56-307)__________________ 14 

18. Dolomite, mottled light brownish-gray 

5YR 6/1), light olive-gray (5Y 

6/1), and pale-red ( 5R 6/2), very 

fine to finely crystalline; contains 

many idiomorphic dolomite crystals 

Cumulative 

thick-

(feet) 

ness 

328 

324 

319 

296 

294 

282 

280 

267 

260 

248 

SECTION 41.--J erome-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

18. Dolomite, etc.-Continued 

and large calcite vugs as much as 1 in. 

in diameter; gastropod remains occur in lower 2 ft; thick-bedded (beds 

ure generally 2-3 ft thick). (H56-

Subunit 

thickness 

(feet) 

303, 304, 305, 306) ----------------- 42 

17. Dolomite, medium-gray (N 5), very 

slightly calcitic, very fine grained, 

thick-bedded in finely laminated beds 

as much as 1lh ft thick separated by 

partings of sandy shale ; contains 

some calcite-filled brachiopod casts ; 

weathers light olive gray. (H56-

287) ------------------------------ 9 

Aphanitic dolomite unit: 

16. Dolomite, medium light-gray, aphanitic; forms one resistant bed; 

weathers light gray----------------- 3 

15. Dolomite, light brownish-gray (5YR 

6/1) with pale-red stains, very finely 

and evenly crystalline, thinly laminated ; weathers light brown. (H56-

286)------------------------------- 6 

14. Dolomite, light olive-gray ( 5Y 6/1), 

aphanitic; conchoidal to subconchoidal fracture; contains scattered spherical bodies that appear to be dolomitized calcispheres; contains scattered 

gray concentrically banded chert nodules as much as 2 in. in diameter ; 

thin-bedded (beds are 2 in. thick) ; 

weathers yellowish gray. (H56-285) _ 6 

13. Sandstone, pinkish-gray (5YR 8/1), 

poorly sorted ; contains quartz grains 

ranging in size from silt to about 0.5 

mm in diameter ; larger grains are 

subrounded to rounded ; smaller 

grains are subangular ; most grains 

are etched by carbonate replacement; 

composed at least 20 percent of dolomitic cement; weathers light reddishbrown and forms distinctive low cliff. 

(H56-284) _________ ,_______________ 2 

12. Dolomite, light-gray, aphanitic; contains irregular stringers of medium 

quartz sand composed of well-rounded frosted detrital grains__________ 8 

11. Covered interval, possibly red-tinted 

shale---------------·--------------- 2 

10. Dolomite, mottled pinkish-gray (5YR 

8/1) and light brownish-gray ( 5Y R 

6/1), aphanitic; conchoidal fracture; 

lower 4 ft. brecciated and cliff forming ; has pelletal structure and very 

small to microscopic dolomite-filled 

cavities ; contains possibly ghost structures of calcispheres ; contains a very 

small amount of very fine grained detrital quartz; weathers pinkish gray. 

(H56-283)------------------------- 9 

Cumulative 

thickness 

(feet) 

234 

192 

183 

180 

174 

168 

166 

158 

156 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 163 

SECTION 41.-J erome-Continued 

:Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit-Continued 

9. Dolomite, mottled pale red (5R 6/2) 

to grayish pink (5R 8/2), aphanitic; 

conchoidal fracture; contains very 

small to microscopic vugs and fissures 

filled with crystalline dolomite ; lower 

part consists of two beds separated by 

less than 1 in. of purplish-gray shale ; 

upper part consists of one 3-ft. bed 

containing some gray chert; weathers 

Subunit 

thickness 

(feet} 

light yellowish gray. (H56-282) ___ 7 

8. Dolomite, light-gray (N7) to light 

brownish-gray (5YR 6/1) (some beds 

mottled pale red), aphanitic, conchoidal fracture; thick-bedded (beds 

are 2 ft. thick) individual dolomite 

beds are separated by beds of grayish-purple shale averaging a few 

inches in thickness ; dolomite beds 

weather light yellowish brown. 

(H56-280, 281>-------------------- 22 

7. Dolomite, pinkish-gray (5YR 8/1) 

light brownish-gray (5YR 6/1), and 

light olive-gray (5Y 6/1; mediumbedded (beds are 1-2ft. thick) ; dolomite beds are separated by shale partings, which average 2 in. thick ; dolomite beds are generally aphanitic and 

have a conchoidal fracture; parts of 

rocks are very finely pelletal ; pellets 

are generally 0.1-0.2 mm in diameter, 

but some are as large as several millimeters. Contains sparsely scattered 

generally subangular to angular detrital quartz grains ranging in size 

from very fine to fine ; weathers 

yellowish gray. (H56-277, 278, 279) 30 

6. Dolomite, medium-gray (N 5) to medium dark-gray (N 4), thin-bedded 

(beds are less than 1 ft thick) ; contains thin shaly partings; aphanitic; 

conchoidal fracture; very finely laminated; contains two kinds of chert: 

(1) irregular small nodules of lightgray chert having a limonitic rind 

within dolomite beds and (2) lenses 

of dark-gray chert emplaced in shale 

partings between dolomite beds in 

such a manner that bedding is slightly 

disturbed ; weathers pale yellowish 

brown. (H56-274, 275, 276) -------- 27 

Fetid dolomite unit: 

5. Dolomite, medium light-gray (N 6) to 

light-gray (N 7), fine- to mediumgrained, saccharoidal, and laminated 

as subunit 1; in places, brecciated and 

contorted; weathers yellowish gray. 

(H56-273) -------------··------------ 6 

4. Dolomite, medium light-gray (N 6) to 

medium-gray (N 5), massive, cliffforming, fine-grained, saccharoidal ; 

contains idiomorphic to hypidiomor-

.'f~10606& 8 

OumuZative 

thickness 

(feet) 

149 

142 

120 

90 

63 

SECTION 41.-J erome-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Subunit 

thickFetid dolomite unit-Continued <i!!:) 

4. Dolomite, etc.-Continued 

phic dolomite crystals; finely laminated, the laminae consisting of dark, 

probably organic, material ; contains 

small calcite vugs throughout ; fetid 

odor; weathers yellowish gray. 

(H56-271, 272)-------------------- 15 

Tapeats Sandstone: 

3. Dolomite, pale-red (lOR 6/2), very fine 

grained, argillaceous ; contains stringers 

of detrital quartz grams ranging in size 

from silt to very fine ; occurs in layers 

as much as 1 in. thick interbedded with 

red- and green-tinted shale. (T56-572, 

OumuZative 

thickness 

(feet) 

57 

T57-343) ---------------------------- 6 42 

2. Shale, silty, and fissile siltstone, red- and 

green-tined, poorly exposed____________ 14 36 

1. Sandstone, grayish-red ( 5R 4/2) , thickbedded, coarse-grained, very crossbedded; lower 1% ft is conglomeratic, 

containing pebbles as much as 3 in. in 

diameter. (T57-344) -----·------------ 22 22 

Precambrian: Deception Rhyolite. 

SECTION 42.-Upper Hull Canyon 

[North of Jerome-Prescott Road and west of BM 5910, about 2 miles 

west-southwest of Jerome (sees. 28 and 29, T. 16 N., R. 2. E., unsurveyed] 

This section was measured and sampled in 1953 but not 

by the standards employed in 1956. No r~k samples were available for examination. Reference to this section is made only 

to state thickness 3.1lld to fix derivation of some important fossil 

collections that are discussed. 

SECTION 43.-Verde River at Sycamore Creek 

[North side of Verde River, a quarter of a mile above junction of 

Sycamore Creek (Clarkdale quadrangle, about center of SE~ sec. 7, 

T. 17 N., R. 3 E., unsurveyed). Photograph lots AK 2856, 2857. 

Measured by Curt Teichert and R. L. Harbour, 1956] 

Martin Formation: 

Jerome Member : 

Upper unit: 

33. Sandstone, grayish orange-pink (lOR 

8/2), poorly sorted, fine- to coarsegrained;. quartz grains more than 0.3 

Subunit 

thickness 

(feet) 

mm in diameter are generally well 

rounded ; those less than 0.3 mm in 

diameter are angular to subangular; 

contains some calcareous cement; 

thin-bedded, friable ; contains many 

broken and wrinkled beds; weathers 

pale red. (T56-571) --------------- 10 

32. Dolomite, grayish orange-pink (lOR 

8/2), very finely crystalline; contains 

scattered detrital quartz, mostly fine 

grained or smaller, making up as 

much as 3 percent of rock; some parts 

are more sandy and contain rounded 

quartz grains as much as 1 mm in diameter ; massive, poorly bedded ; 

weathers pale red. (T56-570)______ 18 

OumuZative 

thicknesa 

(feet) 

367+ 

357+ 
164 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 43. Verde River at Sycamore Greek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

31. Dolomite, grayish-pink (5R 8/2), 

finely crystalline; some beds are laminated and have slump structures in 

places; thick-bedded to massive; 

weathers pale red. (T56-56H) ___ _ 

30. Dolomite, pale-red (5R 6/2), very finely 

crystalline, saccharoidal ; weathers 

into fine powder composed of dolomite 

crystals; contains scattered detrital 

quartz grains which are fine or smaller; larger grains are highly shattered; 

massive, having only indistinct bedSubunit 

thickness 

(feet) 

6 

ding. (T56-568) ___________________ 14 

29. Dolomite, grayish-pink, saccharoidal, 

unbedded, highly weathered and poorly exposed_________________________ 10 

28. Dolomite, light olive-gray (5Y 6/1), 

. finely to coarsely crystalline, sa~­

charoidal ; has some vuggy porosity ; 

generally unbedded; weathers light 

olive gray. ( T56-566, 567) ________ 33 

27. Dolomite, slightly calcitic, very pale 

orange (lOYR 8/2) to grayish-orange (lOYR 7/4), very finelyerystalline; contains many long narrow 

tubes, partly calcite-filled, oriented 

parallel to bedding plane; bedding indistinct; weathers pale yellowish 

brown. (T56-565) ---·-------------- 2 

26. Dolomite, pinkish-gray (5YR 8/1), very 

finely crystalline, saccharoidal; lower 1-2 ft contains Gongeriomorpha 

andrusovi Stoyanow and Arizonella 

allecta Stoyanow; 2 ft above this 

fauna is a conodont assemblage containing Palmatolepis triangularis 

Sannemann, H indeodella sp., Synprioniodina sp., Spathognathus sp., 

and Falcodus? sp. ; indistinctly bedded; weathers light olive gray. 

(T56-564) -------------------------- 7 

2·5. Dolomite, grayish orang~pink (5YR 

7/2), very finely crystalline, saccharoidal, argillaceous; contains scattered detrital quartz silt constituting 

as much as 5 percent of rock and a 

few rounded quartz grains as much 

as 0.6 mm in diameter; thin-bedded; 

becomes shaly in upper 2ft; weathers 

grayish orange. (T56-563) ----·---- 7 

24. Dolomite, grayish-pink (5R 8/2), finely 

crystalline; contains as much as 1-2 

percent detrital quartz silt; argillaceous ; very fissile, having some flaggy 

beds 2 in. thick; weathers grayish 

pink; poorly exposed. (T56-562) ___ 12 

23. Dolomite, calcitic, grayish orange-pink 

( 5Y R 7/2) , finely crystalline, saccharoidal, very porous ; uppermost 

foot is abundantly fossiliferous 

Cumulative 

thickness 

(feet) 

339+ 

333+ 

31H+ 

276+ 

274+ 

267+ 

260+ 

SECTION 43. Verde River at Sycamore Greek-Continued 

Martin ]'ormation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

23. Dolomite, etc.-Continued 

(stromatoporoids, Aulopora sp., 

Thamnopora sp., rugose coral, brachiopods) ; massive, having indistinct 

bedding; weathers pale yellowish 

brown. (T56-561) -----------------

22. Dolomite, brownish-gray (5YR 4/1) to 

light brownish-gray (5YR 6/1), 

finely to medium-crystalline; has 

vuggy porosity ; contains small chert 

fragments; thick-bedded, cliff-forming; weathers light olive gray. 

(T56-560) ------------------------ 21. Dolomite, light-gray (N 7), very finely 

crystalline ; contains much poorly 

sorted detrital quartz, forming as 

much as 50 percent of rock; larger 

grains are rounded to subrounded, are 

as much as 1.2 mm in diameter, and 

have slightly etched surfaces; medium-bedded; weathers grayish pink. 

Subunit 

thickness 

(feet) 

5 

9 

( T56-559) ------------------------- 5 

20. Alternations of light-gray finely crystalline dolomite and grayish-purple 

shale______________________________ 15 

lH. Dolomite, light olive-gray, finely to very 

finely crystalline ; similar in appearance to subunit 18 but porous and 

softer. (T56-558)_________________ 9 

18. Dolomite, slightly calcitic, light olivegray (5Y 6/1), coarsely crystalline, 

saccharoidal; consists of tightly interlocked hypidiomorphic dolomite crystals surrounded by thin calcite films ; 

hence, weathers into a coarse powder 

composed of dolomite grains ; poorly 

bedded, massive, cliff-forming; weathers light olive gray. (T56-557) ____ 9 

17. Dolomite, light-gray, very slightly calcitic, finely crystalline, thin-bedded except for massive 1-ft bed at base. 

(T56-556)_________________________ 7 

16. Dolomite, light olive-gray (5Y 6/1), 

very finely crystalline, saccharoidal, 

thick-bedded; weathers into poorly 

rounded yellowish-gray rubble. 

(T56-555)_________________________ 5 

15. Dolomite, light- to medium-gray, some 

pale-red mottling in upper half; finely 

crystalline. (T56-554) ------------- 6 

14. Dolomite, grayish orange-pink (5YR 

7 /2), very finely crystalline, saccharoidal, thin- to medium-bedded; 

weathers light olive gray. (T56-

553) ------------------------------ 3 

13. Dolomite, light-gray, finely crystalline; 

forms one resistant bed_____________ 4 

12. Dolomite, light- to medium-gray, some 

pale-red mottling in upper half; 

finely crystalline___________________ 6 

Cumulative 

thickness 

(feet) 

248+ 

243+ 

234+ 

229+ 

214+ 

205+ 

196+ 

189+ 

184+ 

178+ 

175+ 

171+ 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 165 

SECTION 43. Verde River at Sycarnore Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

Subunit 

thickness 

(feet) 

11. Dolomite, irregularly laminated pinkish-gray (5YR 8/1) and yellowishgray (5Y 8/1), very finely crystalline, 

saccharoidal; contains scattered small 

lenses of gray chert; medium-bedded 

(beds are less than 2 ft thick) ; 

weathers pinkish gray. (H56-302) __ 13 

10. Dolomite, grayish-pink, medium-crystalline, saccharoidal ; laminated by 

layers of rounded medium to coarse 

quartz grains______________________ 4 

9. Dolomite, pinkish-gray ( 5Y R 8/l), very 

finely crystalline, saccharoidal, thinbedded ; weathers yellowish gray. 

(H56-301)_________________________ 6 

8. Dolomite, yellowish-gray (5Y 8/1) with 

streaks and laminae of light brownish-gray (5YR 6/1), very finely crystalline, saccharoidal ; contains a 

small amount of quartz silt; invertebrate tracks occur on bedding planes ; 

mottling indicates activity of mudburrowing animals ; thick-bedded 

(beds are as much as 3 ft thick) ; 

weathers yellowish gray. (H56- 300) _______________________________ 12 

7. Dolomite, medium light-gray, finely 

crystalline, saccharoidal, thin-bedded_ 4 

6. Dolomite, medium light-gray, finely 

crystalline, saccharoidal, thick-bedded 

(beds are as much as 3ft thick)____ 9 

5. Dolomite, mottled shades of pale red 

(5R 6/2 to lOR 6/2), very finely crystalline, saccharoidal; weathers into 

dolomitic powder ; slope-forming; 

weathers pale red. (H56-299) ______ 5 

4. Dolomite, grayish orange-pink ( 5Y R 

7/2), finely crystalline; has irregularly distributed porosity ; contains 

crinoid ossicles and gastropod ( ? ) remains; on weathering tends to disintegrate into dolomitic siltlike powder; 

weathers pale red. (H56-297, 298) __ 21 

3. Dolomite, pinkish-gray ( 5YR 8/1), very 

finely to finely crystalline, saccharoidal, friable; on weathering tends 

to disintegrate into dolomitic siltlike 

powder; weathers grayish orange 

pink. (H56-296) ------------------ 21 

2. Dolomite, pinkish-gray ( 5YR 8/1), very 

finely crystalline, laminated ; some 

beds are brecciated ; uppermost 2 ft. is 

very sandy, containing shattered 

rounded quartz grains as much as 0.7 

mm in diameter; thin-bedded; weathers yellowish gray. (H56-294, 295) _ 12 

Cumulative 

thickness 

(feet) 

165+ 

152+ 

148+ 

142+ 

130+ 

126+ 

117+ 

112+ 

91+ 

70+ 

SECTION 43. Verde River at Sycarnore Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic dolomite unit: 

1. Dolomite, more or less calcitic, pinkishgray (5YR 8/1), very finely crystalline to aphanitic; part has conchoidal 

fracture; contains very little detrital 

quartz greater than silt size; thinbedded; weathers pinkish gray; during weathering rock tends to disintegrate into a fine chalklike dolomitic 

Subunit 

thickness 

(feet) 

Cumulative 

thickness 

(feet) 

powder. ( H56-288, 289, 290, 291, 

292,293)--------------------------- 58+ 58+ 

Base of section cut off by fault. 

SECTION 44.-Elden Mountains 

[Eastern slope of Elden Mountains (Flagstaff quadrangle, NW:J4 sec. 30, 

T. 22 N., R. 8 E.). Measured by Curt Teichert and R. L. Harbour, 

1956] 

Martin ]~ormation: Sub- CumuJ erome Member : t~'f:%- ~~~~k~ 

Upper unit: (f:;:) (j!!:) 

16. Covered interval________________________ 14 181 

15. Dolomite, light brownish-gray (5YR 6/1), 

medium-bedded, very fine grained ; 

porous, perhaps due to leaching of 

tubular fossil structures ( ?) ; weathers 

brownish gray. (T56-583) ------------ 2 167 

14. Covered interval________________________ 31 165 

13. Dolomite, light brownish-gray (5YR 6/1), 

thick-bedded, hard, very porous, very 

fine grained; weathers brownish gray. 

(T56-582) --------·-------------------- 2 134 

12. Covered interval________________________ 16 132 

11. Dolomite, light-gray (N 7), thick-bedded, 

hard, very fine grained, very porous ; 

contains brachiopod fragments; weathers light gray. (T56-581) ----------- 9 116 

10. Covered interval________________________ 9 107 

9. Dolomite, yellowish-gray (5Y 8/1), medium-bedded, medium-grained; consists of 

idiomorphic to hypidiomorphic dolomite 

crystals; very porous due to weathering out of tubular fossil structure (Arnphipora?). ( T56-580) --·-------------- 2 98 

8. Dolomite, light-gray, thin-bedded to; 

fl.aggy; otherwise similar to subunit 7; 

weathers very light gray--------------- 3 96 

7. Dolomite, light-gray (N 7), mediumbedded, hard, very porous, very fine 

grained; contains hypidiomorphic dolomite crystals ; contains ghost structures 

of brachiopod or ostracode shells ; contains scattered detrital quartz silt and a 

few larger grains as much as 0.3 mm in 

diameter ; weathers yellowish brown. 

(T56-579) --------------------------- 5 93 
166 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 44.-Elden JJio·untains-Continued 

Martin Formation-Continued Sub- Oun~u­ unit Zative Jerome Member-Continued thick- thickUpper unit-Continued <i!!:) t_}:!~) 

6. Dolomite, pale red-purple (5RP 6/2), thinbedded, hard, laminated, very fine to 

fine-grained, silty; consists of hypidiomorphic dolomite crystals and detrital 

quartz silt; weathers yellowish brown. 

(T56-578) --------------------------- 25 88 

5. Dolomite, light-gray, thin-bedded to 

fl.aggy, fine-grained; weathers light 

gray__________________________________ 12 

4. Dolomite, mottled pale-red ( 5R 6/2) and 

greenish-gray ( 5 GY 6/1), medium-bedded, hard, medium grained ; consists of 

allotriomorphic dolomite crystals having 

crenulated, interlocking boundaries ; contains large open vugs (maximum of 1 

in. in diameter) partly filled with calcite; weathers pale brown. (T'56- 577) __________________________________ 11 

3. Dolomite, pinkish-gray (5YR 8/1) to 

yellowish-gray ( 5Y 8/1), thin-bedded, 

hard ; consists of a very fine grained 

crystal aggregate; weathers yellowish 

gray. ( T56-576) ---------------------- 22 

2. Dolomite, grayish-pink ( 5R 8/2) to light 

olive-gray (5Y 6/1), thick-bedded, finegrained, saccharoidal ; consists of idiomorphic to hypidiomorphic dolomite 

crystals, which in places are embedded 

in larger calcite crystals; weathers 

medium gray to yellowish gray. (T56-

575)---------------------------------- 3 

1. Dolomite, grayish orange-pink ( 5Y R 7/2) 

to pinkish-gray (5YR 8/1) and some 

pale-red (5R 6/2), medium-bedded, fine 

grained, saccharoidal ; consists of hypidiomorphic dolomite crystals ; at least 

one bed is rich in Amphipora; weathers yellowish gray. (T56-573, 574) ____ 15 

Base of section not exposed. 

SECTION 45.-South of Iron King mine 

63 

51 

40 

18 

15 

[On small eastern tributary of Canyon Creek. about 1% miles south 

of abandoned iron mine. (SElANElA sec. 15, T. 9 N., R. 15% E., 

unsurveyed). Photograph lots AK 3235, 3226. MeaHured by Curt 

Teichert, 1960] 

Martin Formation : Sub- Oumuunit Zative Jerome Member: thick- thickUpper unit: <i:!f) <i:!~) 

16. Covered, but contains grayish-pink finegrained fossiliferous limestone having 

abundant silicified specimens of Oyrtospirifer sp. and lftrypa sp ______________ 30 135 

15. Dolomite, pale-red (5R 6/2) mottled grayish-pink ( 5R 8/2) , very fine grained ; 

contains abundant fossil debris (spiriferids, Atrypa sp., crinoid remains) ; 

weathers grayish red__________________ 2 105 

14. Covered-----------------·--------------- 10.5 103 

SECTION 45.-South of Iron King mine-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

13. Dolomite, slightly calcitic, light-brown 

(5YR 6/4) with pale-red mottling, 

medium-crystalline, medium-bedded ; 

weathers pale brown ______________ _ 

12. Covered ----------------------------

11. Limestone, medium-gray (N 5), very 

fine grained; contains scattered detrital quartz grains as much as 1 mm in 

diameter ; thick-bedded; uppermost 3 

ft. is rich in silicified stromatoporoids 

and Thamnopora sp. ; weathers mediSubunit 

thickness 

(feet) 

2 

11.5 

um light gray---------------------- 7 

10. Limestone, medium light-gray (N 6), 

fl.aggy, very fine grained ; uppermost 6 

in. contains stromatoporoid fragments ---------------------------- 2 

9. Sandstone, grayish-pink ( 5R 8/2), 

coarse-grained; contains much calcareous cement; contains well-rounded 

frosted quartz grains; thick-bedded; 

weathers light brown_______________ 6 

8. Covered ---------------------------- 2 

7. Sandst-one, pale-red (5R 6/2), coarsegrained ; contains large amount of dolomitic cement (probably as much as 

50 percent) ; contains well-rounded 

frosted quartz grains; mediumbedded; weathers pale brown______ 2 

6. Covered ---------------------------- 3 

5. Dolomite, very slightly calcitic, grayish 

orange-pink (5YR 7 /2), very fine 

grained ; contains a few small calcite 

vugs; thick-bedded (beds are as much 

as 3 ft thick) ; some beds are laminated; weathers medium gray______ 8 

4. Covered interval except for one 6-in. bed 

of pale-red fine-grained d·olomite, 

4%-5 ft from base of subunit_______ 11 

3. Dolomite, pale-red ( 5R 6/2), very fine 

grained; contains no detrital quartz; 

thin- to medium-bedded ; weathers 

OumuZative 

thickness 

(feet) 

92.5 

90.5 

79 

72 

70 

64 

62 

60 

57 

49 

grayish orange pink ________________ 11.5 38 

2. Covered, but rock probably similar to 

subunit 1-------------------------- 5 26.5 

1. Dolomite, pale-red (5R 6/2), very finely 

crystalline; contains scattered detrital quartz grains as much as 0.5 mm 

diameter; medium-bedded (beds are 

generally 8-18 in. thick, but some are 

thinner) ; finely laminated beds occur 

in middle of subunit; uppermost 1 ft 

contains large colonies of Spongophyllum sp.; weathers generally grayish 

red to pale red ____________________ 21.5 21.5 

Base not exposed, but spring at base of subunit 1 

suggests that base rests on impermeable basement, probably Dripping Spring Quartzite. 
STRATIGRAPHIC SECTIONS OF THE MARTIN FORMATION 167 

SECTION 46.-Sevenmile Creek 

[On east side of Sevenmile Creek, about 5 miles downstream from crossing of U.S. Highway 60. (SE74 sec. 8, T. 2 N., R. 17 E., unsurveyed). 

Photograph Jots AK 1892, 1893. Measured by Curt Teichert, 1960] 

Martin Formation: ~:fi Y/:tfv~- J erome Member : thick- thickness ness Upper unit: (feet) (feet) 

26. Shale, olive, poorly exposed ("green 

shale" zone) ______________________ 42 258 

25. Siltstone, poorly exposed; contains 

three beds of dolomitic limestone ; 

forming, ledges at 5 and 15 ft above 

base, one ledge at top of unit. The 

dolomitic limestone is dark yellowish 

orange (lOYR 6/6), to moderate yellowish brown (lOYR 5/4) ; very finely 

crystalline ; lowest bed contains fish 

plates and crinoid ossicles. Limestone beds weather dark yellowish 

orange. ( T60-91, 92) ___ ----------- 30 

24. Dolomite, very slightly calcitic, lightbrown (5YR 6/4), very finely crystalline ; contains large crinoid stems 

about 15 mm in diameter; contains 

scattered garnet grains as much as 

1 mm in diameter, probably of authigenic origin ; weathers dark yellowish 

216 

orange. (T60-90)__________________ 1.5 186 

23. Limestone, generally light-gray (N 7), 

coarsely crinoidal ; contains fragmental brachiopods ; thick-bedded ; contains a considerable component of 

detrital quartz grains as much as 3 

mm in diameter ; particularly sandy 

in middle part of subunit, where 

large, slightly ribbed atrypids occur; 

weathers light olive gray. (T60-89) _ 20 184. 5 

22. Sandstone, pale yellowish-brown (lOYR 

6/2) , fine-grained ; contains scattered 

larger quartz grains as much as 1 mm 

in diameter; contains a large amount 

of cement composed of calcitic dolomite; thin-bedded, crossbedded; invertebrate parts common on most 

bedding planes ; abundant vertical 

burrows occur in lower half of subunit; weathers moderate yellow. 

(T60-88) ------------------------- 5 

21. Dolomite, calcitic, yellowish-gray ( 5Y 

7/2) , very fine grained, thick -bedded ; 

penetrated by tubular twisting burrow structures about 5 mm in diameter; weathers dusky yellow. (T60-

87)________________________________ 6 

164.5 

159.5 

SECTION 46.-Sevenmile Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Upper unit-Continued 

20. Dolomite, calcitic, yellowish-gray (5Y 

7/2) , finely crystalline ; contains 

lenses and layers of undolomotized 

crinoidallimestone, which are as much 

as 4 in. thick; thin- to mediumbedded; weathers yellowish gray. 

(T60-86) -------------------------

19. Covered-----------------------------

18. Dolomite, very slightly calcitic, grayish 

orange-pink (5YR 7/2), very finely 

crystalline; thin- to medium-bedded; 

contains one 3-ft bed 5-8ft above base 

of subunit; laminated in parts; probably some"vhat silty; lowermost 6 in. 

Subunit 

thickness 

(feet) 

5 

5 

rich in crinoidal debris ; weathers 

light brown. (T60-85) ------------ 10 

17. Sandstone, mottled pale-brown (5YR 

5/2) and very pale orange ( lOYR 8/ 

2) , fine-grained ; has a calcareous cement; medium-bedded, very crossbedded; locally invertebrate tracks 

occur on bedding planes; weathers 

Cumulative 

thickness 

(feet) 

153.5 

148.5 

143.5 

light brown. ( T60-84) ------------- 10 133. 5 

16. Sandstone, grayish-red (5R 4/2), 

coarse-grained to very coarse grained ; 

contains a considerable amount of calcareous-dolomitic cement and crinoid 

ossicles as much as %in. in diameter; 

medium- to thick-bedded, very crossbedded; cliff-forming; weathers pale 

brown. (T60-83)------------------ 8.5 123.5 

Aphanitic dolomite unit : 

15. Dolomite, pale-red (5R 6/2), aphanitic; 

has a very finely clastic texture, in 

which individual clasts are generally 

less than 1 mm in diameter; mediumbedded; weathers grayish orange 

pink. (T60-82) ____________________ 8.5 115 

14. Dolomite, pale-red (lOR 6/2), aphanitic, 

generally homogeneous; contains scattered lighter colored aphanitic clasts 

as much as 2 mm in diameter ; contains a few scattered detrital quartz 

grains as much as 1 mm in diameter; 

thin-bedded ; poorly exposed; weathers yellowish gray. ( T60-81) ______ 10. 5 106. 5 

13. Dolomite, pale-red (lOR 6/2), aphanitic, 

finely brecciated, thick-bedded, partly 

vuggy; weathers grayish orange pink. 

(T60-80)__________________________ 5 96 
168 DEVONIAN ROCKS AND PALEOGEOGRAPHY OF CENTRAL ARIZONA 

SECTION 46.-Sevenmile Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Aphanitic d()llomite unit-Continued 

12. Dolomite, pale-red (R 6/2), aphanitic, 

thin-bedded; contains interbedded 

shale and siltstone layers ; contains 

abundant detrital quartz grains as 

much as about 0.5 mm in diameter; 

poorly exposed ; weathers grayish 

orange. (~79)------------------

11. Dolomite, various shades of pale red 

and pink ( 5R 6/2 to lOR 8/2), brecciated and conglomeratic; consists 

mostly of angular or rounded fragments of aphanitic dolomite, ranging 

from a few to about 20 mm in diameter ; weathers grayish orange. ( T60-

78) _______________________________ _ 

10. Covered (probably thin-bedded aphanitic dolomite). (T60-77) ------------

9. Dolomite, pinkish-gray (5YR 8/1), very 

fine grained but having some aphanitic parts, medium- to thin-bedded ; 

Subunit 

thickness 

(feet) 

7 

5 

11 

very vuggy, most pore spaces empty ; 

weathers yellowish gray____________ 3 

8. Dolomite, grayish orange-pink (lOR 

8/2), aphanitic, medium- to thickbedded; slightly vuggy, pore spaces 

either empty or partly filled with 

ljght-colored calcite; weathers very 

pale orange. (T60-76) ------------- 5 

7. Dolomite, light brownish-gray ( 5YR 6/ 

1), aphanitic, medium-bedded, unlaminated; very vuggy, pore spares 

either empty or filled with only a little 

brown calcite; weathers yellowish 

gray with very pitted surface. ( '1'60-

75)-------------------------------- 11 

6. Dolomite, light brownish-gray (5YR 

6/1), aphanitic, thick-bedded, laminated ; contains small rounded chert 

concretions having brown rinds; 

weathers very pale orange. ( T60-

74) ------------------------------ 7.5 

5. Dolomite, pale-brown (5YR 5;2), subaphanitic, laminated; contains closely 

spaced small irregular calcite vugs; 

weathers pale yellowish brown. 

( T60-73) --------------------------- 3 

Fetid dolomite unit: 

4. Dolomite, pale-red (5R 6/2), mediumcrystalline, very massive, almost unbedded ; contains varying amounts of 

chert, partly in large concretionary 

lumps several feet in diameter; rubbly and conglomeratic zone occurs 

from 6%-8 ft. above base of subunit; 

some beds emit weak fetid odor; weathers light brown with very cavernous 

surface. (T00-69, 70, 71) __________ 12 

3. Dolomite, light brownish-gray ( 5Y R 

6/1), thick-bedded, thinly laminated 

throughout ; generally porous having 

Cumulative 

thickness 

(feet) 

91 

84 

79 

68 

65 

60 

49 

41.5 

38.5 

SECTION 46.-Sevenmile Creek-Continued 

Martin Formation-Continued 

Jerome Member-Continued 

Fetid dolomite unit-Continued 

3. Dolomite, etc.-Continued 

vugs as much as % in. in diameter; 

slightly fetid odor; extensive interstratal solution occurs along some 

bedding planes ; uppermost 5 ft. has 

scattered chert nodules as much as 

% X 1% inches in cross section ; 

weathers light brown _____________ _ 

2. Dolomite, mottled pale-red (5R 6/2) 

and pale-brown ( 5Y R 5/2), coarsely 

crystalline, slightly porous; weathers 

pale reddish brown _______________ _ 

Beckers Butte Member : 

1. Sandstone, light-brown ( 5Y R 6/), 

medium- to coarse-grained ; rich in 

green-tinted mineral grains (glauconite?) ; very weathered and crumbles 

in outcrops. (T00-67, 68) _________ _ 

Precambrian : Volcanic rocks. 

SECTION 47.-Mormon Tank 

Subunit 

thickness 

(feet) 

17.5 

3 

6 

Cumulative 

thickness 

(feet) 

26.5 

9 

6 

[About half a mile southeast of Mormon Tank (Fort Apache Indian 

Reservation, near center sec. 18, T. 4 N., R. 19 E., unsurveyed). 

Photograph lots AK 1989, 1990. Measured by Curt Teichert, 1960] 

Martin Formation : Sub- Oumuunit lative Jerome Member : thick- thickUpper unit (top of section eroded) : tJ:::) <i!!f> 

15. Sandstone, light-brown (5YR 614), fineto medium-grained, hard; has slightly 

calcareous matrix; thin- to mediumbedded; abundant narrow in vertebra te trails having median furrow 

occur on most bedding planes; 10 ft 

above base is one bed containing 

poorly preserved pelecypods having 

possibly pteriid affinities ; weathers 

moderate brown. ( T60--65, 66) _____ 38+ 273+ 

14. Sandstone, brown, thin-bedded, finegrained, soft; matrix slightly calcareous ; poorly exposed ; slope-forming__ .15 

13. Dolomite, grayish (orange-pink ( 5YR 

7 /2), medium-crystalline, hard, slightly crossbedded ; contains Tha~ 

opora sp. and silicified brachiopod 

fragments; weathers light brown. (~64)__________________________ 2 

12. Dolomite, pale-red, fine-grained, lower 

3 ft is sandy; laminated; weathers 

with pitted surface; poorly exposed__ 18 

11. Dolomite, streaky grayish orange-pink 

(lOR 8/2) and grayish-pink (5R 

8/2) , very slightly calcite, very fine 

grained; laminated and in places 

brecciated; weathers light brown. 

( T60-63) ----------------------·---- 4 

10. Dolomite, light brownish-gray ( 5YR 

6/1), very finely crystalline ; sandy 

near base, contains large calcite vugs 

higher up; medium-bedded (beds. 

9-12 in. thick) ; weathers light 

brown. (T60-62)------------------ 12 

235 

220 

218 

200 

196 
REFERENCES CITED 169 

SECTION 47.-Jformon Tank-Continued 

Martin Formation-Continued ~~~t 

Jerome Member-Continued thickUpper unit-Continued <i:!l) 

9. Sandstone, pale-red ( 5R 6/2), finegrained, quartzitic, thin-bedded, 

slope-form~_ng; weathers light- to 

medium-gray. (T60-61) ------------ 21 

Aphanitic dolomite unit: 

Oumulative 

thickness 

(feet) 

184 

[This unit is v'ery poorly exposed; slope is covered with dolomite talus. 

The following descriptions are generalized and based predominantly 

on talus material and a few outcropping rock ledges] 

8. Dolomite, aphanitic, pale-red (5R 6/2) 

to lOR 6/2) to grayish-pink (5R 8/2), 

generally thick-bedded ; some beds 

contain varying quantities of detrital 

quartz; some beds are brecciated or 

contain dolomite clasts. ( T60-58, 

59, 60)____________________________ 41 163 

7. Covered_____________________________ 16 122 

6. Dolomite, pale-red, very fine grained, 

thick-bedded ; contains a few calcite 

vugs as much as 1 mm in diameter__ 10 106-

5. Dolomite, light brownish-gray (5YR 

6/1), aphanitic; in part rich in detrital quartz grains, in part very porous, 

having small cavities either void or 

lined or filled with brown calcite; 

weathers generally yellowish gray. 

(T60-56, 57)----------------------- 15 96 

4. Dolomite, medium light-gray (N 6), 

aphanitic ; contains brown rind chert 

nodules, generally flat, as much as 1 

in. long and a fraction of an inch 

thick_______________________________ 23 81 

3. Dolomite, light brownish-gray ( 5Y R 

H/1) to brownish-gray (5YR 4/1), 

aphanitic; some beds contain scattered detrital quartz grains ; some 

beds are laminated; weathers generally yellowish gray. (T60-54, 55)_ 27 58 

2. Dolomite, pale yellowish-brown (lOY R 

6/2), finely crystalline, thick-bedded, 

laminated; emits weak fetid odor; 

uppermost 8ft cherty and brecciated, 

the silica occurring in spongy lumps 

having saccharoidal texture. (T60-

fi3) -------------------------------- 28 31 

1. Dolomite, pale yellowish-brown (lOYR 

H/2) , finely crystalline, homogeneous, 

hard; emitts weak fetid odor; 

weathers pale yellowish brown. 

(T00-52) --------------------------- 3 3 

Underlain by undifferentiated Beckers Butte 

Member having an estimated thickness of more 

than 100ft. 

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A Pa~ 

Accessibility of rocks studied_________________ 3, 5 

Acervularia davidsonL------------------------ 6, 58 

Acknowledgments____________________________ 16 

Actinostroma ___________ ------------------ ____ 53,57 

Actinostroma sp______________________________ 51 

Aglaeoglypta maem_ _ _ __ _ ___ _ _ _ ____ _ _ __ _ _ _ __ _ _ 62 

Alveolites __ -_ ---- __ ----- ______________________ 66, 92 

Alveolites sp ___ ------------------- _________ 43, 58,90 

Amphipora ___________ 44, 47, 49, 51, 52, 54, 57, 84,93,100 

Amphipora sp_ _________ ___ ___ _______ _ ________ 43 

Amsden, T. W., cited_----------------------- 71 

Amstutz, G. C., c:ited________________________ 80 

Anderson, C. A., and Creasey, S.C., cited__ 8, 

14, 15,17, 25, 26, 29, 32, 33. 40, 41,42 

Andr~e. Karl, quoted_________________________ 78 

Andrews, H. N., Jr., cited____________________ 99 

Anostylostroma ___ ------------------------- ___ 57 

Anostylostroma sp ·- _____ ------------------ ____ 51 

Anthozoans ______ --------------- _____________ 57 

Aphanitic dolomite unit, brecciation in __ 33, 35,36 

chert in _________ ---------- ________________ 33, 88 

clastic rocks in____________________________ 39 

dedolomitization in_______________________ 37 

depositional history______________________ 82 

diagenetic history ___ --------------------- 40,83 

distribution______________________________ 37 

fossils in ______________ - ___ -_________ 33, 37, 40, 41 

general lithology outside Jerome area_____ 33 

intraformational erosion in________________ 33 

invertt~brate trails in _____________________ 33,40 

limestone in______________________________ 37 

mode of deposition_______________________ 40 

mud cracks in ___ ------------------------- 33,40 

red marker bed in_----------------------- 33 

silica in ___________________________________ 36,37 

thickness ______________________________ 19, 20,33 

type section______________________________ 32 

Aphyllopteris sp __ ---------------------------- 89 

Arastra torquata_ -·- ____ _ __ _ __ _ _ __ _ _ _ _ ___ _ ___ _ _ 62 

Arizona Sag _________________________________ _ 

Arizonella ____________________________________ 51,62 

Arizonella allecta_ ---------------------------- 44,62 

Asterosphaera____ _ ___ _ ___ _______ __ __ _ ____ _ __ __ 99 

Atrypa __ __________ _40, 44, 47, 50, 51, 52, 54, 60, 61, 91,92 

Atrypa clarkei_ ___ ------ _ --------------------- 54 

devoniana bentonensis ____________ 49, 54, 58, 90,92 

owenensis _______ ---- ___________________ 54, 58,90 

pronis ____ -_ __ _ ____ ___ _ ___ __ _ __ _ _ _ _ _ ___ ___ 58 

Aubouin, Jean, cited_________________________ 72 

Augusta, Josef, cited_________________________ 29 

Aulocystis sp ____ ---------------- ___ __________ 58 

Aulopora __________________________________ 43, 66,92 

Aulopora sp ____ ------------------------ 43, 44, 48,58 

spp ____ ----------------------- -------- ___ _ 43 

Auzel, Marguerite. See Bourcart, Jacques. 

Aztec Peak, outcrops at_ ____________________ _ 

B 

Bagnold, R. A., cited_________________________ 38 

Barnes, V. E., Cloud, P. E., Jr., and Warren, 

L. E., cited_______________________ 74 

INDEX 

[Italic page number indicates major reference] 

Page 

Barnes, V. E. See Cloud, P. E., Jr. 

Bathurst, R. G. C., cited _____________________ 19,32 

Baxter, J. W., cited__________________________ 99 

Beales, F. W., cited ______________________ 21,99,102 

Becker, .T. H. See Clark, D. L. 

Beckers Butte, complete Devonian section in__ 21 

Beckers Butte Member, age __________________ 27,89 

as channel filL--------------------------- 25 

comparison· with the Jerome Member_____ 2.5 

comparison with the Tap eats Sandstone-_ 2.5 

composition __ -------_--- _____ ------______ 23 

correlation ______ ------ _______ ----_--______ 8.9 

crossbedding in ------------------------ 23 

definition _____________ ----------------____ 15 

distribution _____ ----- ____ ----------- _____ 23, 27 

fossils in__________________________________ 19 

heavy-mineral suites in___________________ 26 

mode of deposition________________________ 27 

paleogeography ____ ----___________________ 27 

thickness __ ------_- _______________ --- __ 19, 20, 22 

Biocoenosis, defined and discussed____________ 55 

Biostromes, in upper unit, Jerome Member___ 43, 

52, 53, 54, 57, 85, 93 

Birina, L. M., cited_------------------------- 99 

Bisphaera __________ ---------------- __________ 99 

Bisque, R. E., and Lemish, John, cited______ 71 

Black, Maurice. See Hatch, F. H. 

Black, W. W., cited__________________________ 86 

Black River, measured section along_________ 106 

Boas, Goerge, quoted_________________________ 11 

Bonet, Federico, cited _______________________ 99,102 

Boswell, P. G. H., cited---------------------- 86 

Botvinkina, L. N., Zhemchuzhnikov, Yu. A., 

Timofeev, P. P ., Feofilova, A. P ., 

and Yablokov, V. S., cited________ 99 

Boucot, A . .T., cited ___________________________ 55,56 

quoted___________________________________ 55 

Bourcart, Jacques, Auzel, Marguerite, and 

Michel, Jean, cited_______________ 83 

Boy Scout Ranch No.1, measured section at_ 13.'1 

steep flexure in area oL__________________ 49 

Brachiopods__________________________________ 8, 

9, 13, 18, 40, 41, 42, 43, 44, 47, 48, 49, 51, 54, 

55,58. 

Brachythyrina ______________ ------------------ 65 

Brachythyrina stringosa __________ -------------- 59 

Bradley, W. H., cited________________________ 102 

Brady, L. F., cited _________________________ 8, 12,44 

Bramkamp, R. A., and Powers, R. W., cited_ 21 

Brannock, W. W. See Shapiro, Leonard. 

Breger, I. A., quoted_________________________ 32 

Breviphyllum sp_ ----------------------- 43, 44, 58,62 

Bromfield, C. S., and Shride, A. F., cited ____ 3,13 

Brown, S.C., and Lauth, R. E., cited_______ 9 

Bryant, W. L., cited __ ----------------------- 89 

Bryozoans ______ ---------------- ____ ---------- 18, 58 

Burrows ___________________________________ 26, 53,66 

Bykova, E. V., and Polenova, E. N., cited___ 91, 

99, 102, 104, 105 

Bykova, E. V., Dain, L. G., and Fursenko, 

A. V _ ---------------------------- 105 

c 

Cadosina __ ----------------------------------- Calcisphaera ____________________ ------ _______ _ 

Calcisphaera timbriata ___________ ------------ __ hexagonata ______ -- _ --- ___________________ _ 

Page 

99 

99 

100 

100 

laevis ______________ --- ___ --- __ ------ __ __ _ _ 99 

robusta_ --------------------------------- 99,100 

Calcisphaerula __ ___ --------------------------- 99 

Calcispheres _________________________ 13, 18, 31, 33, 37, 

40, 41, 42, 45, 49, 50, 51, 53, 54, 65, 99 

Camarotoechia endlichi________________________ 7,15 

sp _____________ ------------------------ 45, 58, 61 

Campbell, A. S., cited ________________________ 97,99 

Canyon Creek, east side, measured section 

along ___________________________ 114, 1S4 

west bank, measured section along_______ 1~~ 

Carbonate rocks, classification, based on chemical composition__________________ 19 

classification, based on origin and environment__--------------------------- ~1 

based on structural and textural features __ --------------------------- ~1 

relationships within gross lithology_______ 67 

terminology ______ ---------- ______ -------- 18 

Carozzi, A. V., cited ____________________ 39, 72, 81,83 

See Wanless, H. R. 

Cayeux, Lucien, cited _________________ 31, 74, 86,102 

Central Arizona, stratigraphic nomenclature __ 13,16 

Cephalopods ___ -------- __________ ------------ 62 

Chaetetes ________________________ ------------__ 51 

Chaetetes sp _________________________ ---------- 58 

Channel fills, Beckers Butte Member________ ~3 

Chapman, F., cited _________________________ 99,102 

Characeae ____ ___________ -_______ ---------- _--- 104 

Chasm Creek, aphanitic dolomite breccia_____ 36 

brown rind chert_________________________ 38 

measured section along___________________ 159 

section along_---------------------------- 5 

Chert, in aphanitic dolomite unit_ ____________ 33,38 

in fetid dolomite unit_____________________ 30 

Chilingar, G. V., cited ________________________ 19,80 

Chlorella ____ ________ -------------------------- 102 

Chlorellopsis ____________ -_______ -------------- 102 

Chlorococcum _________ ------------------------ 102 

Christopher Creek, measured section along___ 133 

Christopher Creek Camping Area, Jerome 

Member,upperunitmissing_____ 47 

measured section at_______________________ 133 

Christopher Island ___________ ---------- 48, 49, 88,94 

Christopher Mountain Ridge, measured sec- tion in____________________________ 1~9 

Christopher Ranch, measured section near_ _ _ 13~ 

Cladopora _____ --------------------------- __ -- 44 

Clark, D. L., and Becker, J: H., cited________ 91 

Clarke, E. de C., Prider, R. T., and Teichert, 

Curt, cited_______________________ 72 

Clarke, J. M., cited ___ ----------------------- 90 

Cloud, P. E., Jr., cited _______________________ 39,57 

See Barnes, V. E. 

Cloud, P. E., Jr., and Barnes, V. E., cited___ 83 

Coccosteus arizonensis_________________________ 44 

Cochleatina _________ -------------------------- 105 

Coelenterates _________________ ---------------- 84 

177 
178 

Page 

Colcord Canyon, Jerome Member, aphanitic 

limestone unit, marginal facies of_ 40 

Upper, measured section in_______________ 117 

Colom, Guillermo, cited______________________ 99 

Color of rocks, factors governing and use of 

terminology_--------------------- 11 Congeriomorpha andrusovi_ __________________ 44,62 

Conodonts ___ ----------------------------- 18, 44,63 Cooksonia _________________________ ____ ------ __ 89 

Cooper, C. L., cited__________________________ 91 

Cooper, G. A., cited _____________________ 9, 14, 15,61 

Coquinas, in upper unit, Jerome Member.___ 52, 

53, 55, 59, 60, 61 

Corals _____________________ 8, 9, 18, 43, 48, 49, 51, 53,57 

Corophioides_ __ __ _ _ ___ ___ ___ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 26 

Correns, C. W., cited_________________________ 39 

Craig, G., cited_______________________________ 56 

Cranaena SP---------------------------------- 45,61 

Creasey, S. C. See Anderson, C. A. Crinoids __________________________ 18, 45, 48, 55, 63,66 

Cross, J. L., Shaw, E. H., and Scheifele, 

Kathleen, cited___________________ 9 

Cuvillier, Jean, cited_________________________ 97 

Cyrtospirifer ------------------------- 52, 61, 65, 91,92 

Cyrtospirijer whitneyL _ -------------- 49, 54, 58, 90,92 

sp ____ ------------ ________ -------------- __ 43, 61 

Cytosphaera ___________ -------------------- ____ 99 

D 

Dain, L. G. See Bykova, E. V. 

D'Albissin, Micheline, cited ________ ._________ 76 

Danchev, V. 1., cited_________________________ 11 

Dangeard, Louis. See Defl):mdre, Georges. 

Darton, N.H., cited _______ · ________________ 6, 7, 9, 13 

Darton, N. H., Lausen, Carl, and Wilson, 

E. D., cited______________________ 15 

Davitashvili, L., cited________________________ 56 

Dawsonites __ --------------------------------- 89 

Decker, C. E., and Merritt, C. A., cited______ 70 

Dedolomitization, in aphanitic dolomite unit. 37 

Defiance Positive area concept________________ 6 

Defiance uplift._------------------------ 8, 40, 47,88 

Defiance uplift, source of sediment_ ________ 38, 85,93 

Defl.andre, Georges, cited_____________________ 102 

Deflandre, Georges, and Dangeard, Louis, 

cited ___ -------------------------- 105 

DeFord, R. K., cited _________________________ 10, 11 

See Goddard, E. N. 

Derville, Henry, cited ___________________ 99,100,102 

Detrital quartz, in aphanitic dolomite unit.__ 38 

in upper unit __________________________ 45, 47,82 

Devonoproductus ______________________________ 61,96 

Devonoproductus vulgaris______________________ 58 

sp_ ------ _ -- __ - _- ___ ---------- _- _ ---- __ _ __ 54 

Diagenesis, role of____________________________ 78 

Diamond Point, Beckers Butte Member, 

contact with Jerome______________ 25 

Jerome Member, limestone_______________ 37 

measured section at_______________________ 140 

Dinichthys ____ -------------------------------- 44, 64 

Diplosphaera ___ ---------------- ___ ----------- 99 

Dipterus sp___________________________________ 44 

Disphyllum __________________________ 47, 49, 51, 58,91 

Disphyllum SP----------------------------- 48, 58,90 

spp _______ -------------------------------- 43 

Dixon, E. E. L. See Strahan, Aubrey. 

Dobrovolny, Ernest. See Huddle, J. W. 

Dolomite, stratified versus metasomatic______ 41 

Dorf, Erling, cited____________________________ 89 

Doubtful Creek measured section along_______ 133 

Downie, Charles, cited_______________________ 102 

Dunbar, C. 0., and Rodgers, John, cited_____ 71 

Durchkieselung process_______________________ 39 

INDEX 

E Page 

Eardley, A. J., cited _________________________ 3, 8, 97 

East Verde River, Beckers Butte Member, 

contact with Jerome______________ 25 

Beckers Butte Member, exposed_________ 24 

Jerome Member, ostracode concentration_ 37,40 

measured section along_------------------ 144 

Eastern Arizona, stratigraphic nomenclature. 16 

Echinoderms _______ ------------------------__ 63 

Echinoids. ----------------------------------- 44,63 

Elden Mountain, outcrops at_________________ 5, 8 

Elden Mountain section, fish remains from___ 9 

Elden Mountains, measured section in_______ 165 

Electron-microscope investigations___________ 76 

Elston, W. E., cited__________________________ 8 

Emery, K. 0., and Rittenberg, S. C., cited___ 80 

Endlichi, Camarotoechia_______________________ 7, 15 

Engelhardt, Wolf von, cited__________________ 83 

Epis, R. C., Gilbert, C. M., and Langenheim, 

R. L., Jr., cited ___________ ------- 13 

Eumegalodon _____ ----------------------- ___ __ 62 

F 

Fairbridge, R. W., cited______________________ 71 

Falcodus sp ______________________ --------- 44 

Fearing, J. L., Jr., cited______________________ 26 

Feofilova, A. P. See Botvinkina, L. N. 

Fetid dolomite unit, chert in_________________ 30 

depositional history_______________________ 81 

diagenesis of______________________________ 83 

distribution _______ ----------------------- 32 

fossils in__________________________________ 31 

lamination in_____________________________ 30 

stages of diagenetic processes______________ 32 

thickness ______________________________ 19, 20,29 

Fibrosphaera ___ ________________ ----------- 99 

Field, R. M., cited___________________________ 74 

Fish plates_-------------------- 8, 40, 43, 44, 47, 55,64 

Fish remains __ ----------------------- 9, 37, 40, 44,64 

Flying V Canyon, brown rind chert__________ 38 

measured section along___________________ 107 

Folk, R. L., cited ___ ------------------- 10, 21, 74, 75 

Fossils, in Martin Formation_________________ 19 

Jerome Member, aphanitic dolomite unit. 33, 

37, 40,41 

upper unit ___________________ 42, 43, 47, 49,55 

mentioned by A. B. Reagan______________ 6 

mode of preservation __ ------------------- 56 

silicification oL-------------------------- 86 

Frosting of sand grains, origin of______________ 38 

Fiichtbauer, Hans, cited______________________ 86 

Fursenko, A. V. See Bykova, E. V. 

G 

Galbraith, F. W. See Short, M. N. 

Gantnier, R. F., quoted______________________ 26 

Gastropods _____________________ 9, 18, 42, 44, 49, 51,61 

Gerronostroma __________________ ---------- ____ 52, 57 

Gerronostroma sp __ --------------------------- 53 

Gibson, W. See Strahan, Aubrey. 

Gilbert, C. M. See Epis, R. C. 

See Peterson, N. P. Gilbert, G. K., cited _________________________ _ 

Gilluly, James, cited __ ----------------------- 13, 14 

Ginsburg, R. N., cited_---------------------- 82 

Glauconite __ --------------------------------- 39 

Globe, section near--------------------------- 3 Glover, J. E., cited___________________________ 102 

Goddard, E. N., Trask, P. D., DeFord, R. K., 

Rove, 0. N., Singewald, J. T., 

and Overbeck, R. M., cited______ 11 

Goldich, S. S., and Parmelee, E. B., cited____ 71 

Goldsmith, J. R. See Graf, D. L. Goniatites ____________________________________ 62,92 

Gothan, Walther, cited_______________________ 32 

Grabau, A. W., cited ______________________ 20, 21,74 

Graf, D. L., cited ____________________________ _ 

Graf, D. L., and Goldsmith, J. R., quoted __ _ 

Graham, J. J. See Schenck, H. G. Granulosphaera ____ __________________________ _ 

Gregory, H. E., cited ________________________ _ 

Grunau, H. R., cited.------------------------

Guerrero, R. C., and Kenner, C. T., cited ___ _ 

Gumbel, C. W., cited _______________________ _ 

Gutschick, R. C., cited ______________________ _ 

H 

Hacquaert, A. L., cited _____________________ _ 

Hadding, Assar, cited _______________________ _ 

Hagn, Herbert, cited.------------------------

Harshbarger, J. W. See Shride, A. F. 

Harshman, E. N. See Short, M. N. 

Hatch, F. H., Rastall, R. H., and Black, 

Maurice, cited ___________________ _ 

Hathaway, J. C., quoted.--------------------

Hathaway, J. C., and Robertson, E. C., 

cited ____ --------- _____ -----------

Page 

71 

41 

99 

11 

19 

78 

15 

99,102 

19,74 

99 

76 

76 

83 

Heald, M. T., cited-------------------------- 74 

Hecker, R. F., cited-------------------------- 56 

Hedeia _____ _________ --------------------- _ --.- 89 

Hedgpeth, W. J., cited_______________________ 56 

Heindl, L.A., and Lance, J. F., cited________ 3 

Hessland, Ivar, cited_________________________ 56 

Hexagonaria __________ ------------------ 47, 58, 66,92 

Hexagonaria accidens _______________________ 51, 58,90 

sp ________________ ------------------ 44, 58, 62,90 

spp____ ___ ____ _ ____ __ _ ____ ____ _ __ ____ ___ _ _ 43 

Hicklingia. ------------------------------.---- 89 

Hill, Dorothy, cited.------------------------- 86 

Hindeodella sp .. --------------- ___ ----. __ . ---- 44 

Hinds, N. E. A., cited________________________ 7, 24 

Hippurites ... --------------------------------- 105 Holbrook Sag ____________________________ ---- 9 

Horn af Rantzien, Henning, cited_____________ 99 

Horton Creek, measured section along________ 135 

Hostimella SP--------------------------------- 89 

Hotz, E. E., Krausel, Wolfgang, and Struve, 

Wolfgang, cited_________________ 58 

Hucke, Kurt, cited-----------------·---------- 78,80 

Huddle, J. W., and Dobrovolny, Ernest, 

cited--------_-------------------- 7, 

8, 9, 14, 15, 24, 38, 42, 45, 48, 51, 52, 53, 

57, 87, 88, 97. 

Huff, L. C., cited_____________________________ 17 

Hull Canyon, Upper, measured section in____ 163 

Hunter Creek, measured section along________ 131 

Hussakof, Louis, cited ___________________ 9, 12, 44,64 

Hutchinson, G. E., cited_____________________ 56 

Hypotetragona. _____________ ------------ ______ 40,63 

Hypotetragona sp _____ ------------------------ 91,92 

Idiostroma. ----------------------------------- 52,57 

Idiostroma sp _____________ -------------------- 53 

Illigata ___ ------------------------------------ 105 

Illing, L. V., cited____________________________ 41 

Insoluble residue cycles in carbonate rocks____ 71 

Iron King Mine, measured section near.______ 166 

Irving, J.D., cited___________________________ 86 

Irving, R. D., and Van Rise, C. R., cited ___ - 86 

Island Mesa beds _________________________ 7, 9, 15,44 

J 

Jerome, Jerome Member, aphanitic dolomite 

unit, sandstone subunit._________ 39 

Jerome Member, coralliferous dolimite, 

relation to Hull Canyon section._ 43 

subunits in type section. _________ ---- 42,43 

measured section near __________________ 6, 7,161 

rock sequence in area of.__________________ 17 

Tapeats Sandstone, similadty to top of 

Beckers Butte Member___________ 26 
Jerome Formation ________ ---------------- ___ _ 

Jerome Member, age_ ..... _____ ._.---- ______ . 

correlation ..... --._ ... _-.... _ ... _- .. ___ ._._ 

depositional environment and diagenetic 

Page 

15 

90 

90 

history of the carbonate facies.___ 78 

fossils in .. -------------------------------- 1G, 97 

gross lithological aspects oL__________ ____ 67 

insoluble-residue cycles in carbonate 

sequences ______ ------_____________ 71 

textme of aphanitic carbonate rocks______ 7 4 

thickness ____ -------------------------- 19, 20,88 

See respective units. 

Jones, 0. T. See Strahan, Aubrey. 

J:ux, Ulrich, cited_____________________________ 57 

K 

Kabelac, Fritz, cited. ______ ----------________ 76 

Kaisin, F., cited .. ---------------------------- 102 

Karpinski, A., cited___________________________ 99 

Kelley, V. C., cited___________________________ 9 

Kenner, C. T. See Guerrero, R. C. 

Khvorova, I. V., cited ________________________ 50,73 

Kindle, E:. M., cited .... ---------------------- 74,91 

quoted. _____ ----------------------------- 74 

Kirk, Edwin, cited.-------------------------- 6,15 

Kloedenella sp _________ ----------------------- 92 

Kohl Ranch, Jerome Member, aphanitic limestone unit, marginal facies oL .. -- 40,48 

Jerome Member, fetid dolomite unit 

missi:o.g ___________ ------------- ___ 37 

measured section at. .... ------------------ 136 

Konishi, Kenji, cited ________________ 99,100,102,104 

Kottlowski, F. E., cited---------------------- 91 

Krause!, Wolfgang. See Hotz, E. E. 

Krieger, M. H., cited _______________________ 8, 17,26 

Krynine, P. D., eiJ;ed_________________________ 11 

Kuenen, Ph. H., and Perdok, W. G., cited___ 38 

Kuenen, Ph. H., and Ten Haaf, E., cited_____ 72 

Kuhn, T .. H. See Short, M. N. 

L 

Laird, W. M., cited__________________________ 91 

Lance, J. F. See Heindl, L. A. 

Lang, W. H., cited___________________________ 89 

Langenheim, R. L., Jr., cited_________________ 92 

See Epis, R. C. 

Lapparent, Jacques de, cited _________________ 73,99 

Lausen, Carl. See Darton, N. H. 

Lausen, Carl, and Wilson, E. D., cited_______ 7, 41 

Lauth, R. E. Stie Brown, S.C. 

Lecompte, Marins, cited ___ ------------------ 57 

Lee, W. T., cited_____________________________ 6 

Lehner, R. E.,-cited__________________________ 8 

Leiosphaera ___ ____ -- __________ ---------------- 89 

Leischner, Winfried, cited____________________ 99 

Le Maitre, D., cited__________________________ 99 

Lemish, John. Bee Bisque, R. E. 

LeRoy, L. W., and Schieltz, N.C., cited_____ 100 

Lesley, J.P., cite:d___________________________ 71 

Limestone, autoehthonous versus allochtho- nous _________________ -------------- 21 

Beckers Butte Member___________________ 25 

in aphanitic dolomite unit_ ____________ 33, 37,83 

in fetid dolomite unit.____________________ 31 

in upper unit_ _______ 44, 45, 48, 49, 50, 51, 52, 70, 84 

Limestone Hills, measured section in_________ 157 

outcrops in_______________________________ 5 

Limoptera •. _____ ----------------------------- 62 

Lindgren, Waldemar, cited ___________________ 13,16 

Lithographic limestone_______________________ 15 

Lithographic limestone. See Aphanitic dolomite unit, type section. 

Location of report area_______________________ 3 

Loeblich, A. R., Jr., and Tappan, Helen_____ 104 

Lombard, Augustin, and Monteyne, Roger, 

cited._ .. ------------- 90, 99,100,102,104 

INDEX 

Loranger, D. M., cited ______________________ _ 

Lost Tank Canyon, Beckers Butte Member, 

gradational unit_ ________________ _ 

measured section in ______________________ _ 

southwest branch, measured section in._. 

Lund, E. H., cited ___________________________ _ 

Luster mottling._----------------------------

M 

Page 

92 

25 

118 

1~1 

86 

7~ 

MacCarthy, G. R., cited_____________________ 11 

Macgeea ______ ---------------------------- ____ 51 

Macgeea proteus ___ --------------------------- 92 

McKee, E. D., cited. ________ 8,12,15, 26, 27, 72, 81,97 

See Shride, A. F. 

McKee, E. D.; and others, cited______________ 81 

McLaren, J.D., cited________________________ 92 

McNair, A. H., cited.------------------------ 14,26 

Macropetalichthys ____________ . ---------------- 7, 14 

Manticoceras sinuosum________________________ 92 

Martin Formation, age and correlation_______ 89 

comparison with other Devonian strata in 

the Rocky Mountain province____ 91 

measured sections________________________ 105 

paleogeography----- ______ ---------------_ 96 

summary of facies pattern.--------------- 9~ 

See specific separate units. 

See Stratigraphic section. 

Martin Limestone____________________________ 1~ 

Martin Limestone, fossils in__________________ 13 

Marvine, A. R., cited________________________ 6 

Mather, K. K., cited.------------------------ 19 

Mazatzal Land _______ ------------------------ 7, 45 

Measured sections. See Stratigraphic section. 

Merriam, C. W., cited. ___ ------------------- 91,92 

See Nolan, T. B. 

Merritt, C. A. See Decker, C. E. 

Methods of study. __ ------------------------- 9 

Michel, Jean. See Bourcart, Jacques. 

Miklukho-Maklaj, A. D., cited_______________ 104 

Miller, S. A., cited___________________________ 99 

Milon, Y., cited______________________________ 99 

Mingus Mountain, outcrops at_ _____________ _ 

Mobius, Karl, quoted________________________ 55 

Mogollon Sag ____________________ -------------

Molluscs _______ ------------------------------ 6t 

Monteyne, Roger. See Lombard, Augustin. 

Moore, R. T. See Wilson, E. D. 

Morenci Shale ..•. ---------------------------- 16 

Mormon Tank, measured section near________ 168 

Mount Elden Formation_____________________ 1~ 

Mount Elden section, fossils in_______________ 44 

Mount Martin .. ----------------------------- 12 

Mud cracks._-------------------------- 33, 40, 47, 82 

N 

Naeglin Rim, Jerome Member, aphanitic 

limestone unit, marginal facies oL 40 

Jerome Member, upper unit, unusual rock 

types _____________ --------________ 50 

measured section in __ .. ------------------ 1~5 

Natanes Plateau, basalt cover_ ______________ _ 

Neave, S. A., cited___________________________ 104 

Nervostrophia ___ ------------------------------ 92 

Nervostrop.~ia SP------------------------------ 58 

Noble, L. F., cited___________________________ 12 

Nolan, T. B., Merriam, C. W., and Williams, 

J. S., cited________________________ 91 

Northern Arizona, stratigraphic nomenclature. 1~ 

Nudirostra albertensis _ ---------------------- __ 92 athabascensis ___ _________________ .. _ _ _ _ _ _ __ 92 

gibbosa seversoni.._________________________ 92 

walcotti ... ---------------------------- 92 walcottL _____ . _ -- ____________ .. --. ___ . _ _ _ 92 

179 

0 

Page 

Oak Creek Farm Road, measured section 

along_____________________________ 116 

Oil and gas, potential source of. __ ------------ 9 

Orodus. ___ ---------------------------------- _ 15 Orthislaevis___________________________________ 6 

,Ostracodes. ___ • 13,18, 37, 40, 41, 42, 45, 49, 51, 54, 63, 66 

Overbeck, R. M. See Goddard, E. N. 

Ozonkowa, Helena, cited_____________________ 104 

p 

Pachyphyllum. ------------------------- 57, 58, 66,92 

Pachyphyllum woodmani..____________________ 90 

SP---------------------------------- 53, 54, 58,90 

Paleor.oic inliers in basalt t.errane_____________ 5 

Palmatolepis triangularis ______________________ 44,90 

Parmelee, E. B. See Goldich, S. S. 

Patnode, H. W., cited________________________ 11 

Paul, Henry, cited ... ------------------------ 99 

Paurorhynchus endlichi._______________________ 15 

Pebbles and cobbles, along southern margin 

of Colorado Plateau. __ ----------- 8 

Peck, R. E., cited____________________________ 99 

Pelecypods _________________________________ 9,18, 62 

Perdok, W. G. See Kuenen, Ph. H. 

Peterson, N. P., cited .. ---------------- 14, 15, 55,97 

Peterson, N. P., Gilbert, C. M., and ~uirk, 

G. L., cited_______________________ 14 

Petroliferous odor of rocks._------------------ 8 

Pettijohn, F. J., cited .. __________ 11,19,21, 75,76,80 

Pia, Julius, cited._--------------------------- 102 

Pinal Creek, measured section along__________ 152 

Pine Island _____________________________ 45, 47, 88,95 

Platyrachella ____________________________ 49, 50, 52,65 

Platyrachella mcbridei.. _______________________ 58,90 

sp.--------------------------------------- 43 

Polenova, E. N. See Bykova, E. V. 

Polonskaya, B. Ya., cited._------------------ 104 Polyderma. _ _ _ _ __ _ _ _ _ _ _ _ _ __ _ _ ___ _ _ _ _ __ _ _ _ _ _ _ __ 99 

Polygnathus normalis. ------------------------ 44,90 

Powers, R. W. See Bramkamp, R. A. 

Praechara _____ _______________ .. -.------------- 99 

Previous work in area________________________ 6 

Price, W. E., cited___________________________ 8 

Prider, R. T. See Clarke, E. de C. 

Protozoans._--------------------------------- 57 

Psilophyte flora. __ ---------------------- 9,17, 28,89 

Pteropods ________________________ 49, 51, 53, 54, 62,66 

Pyctodus bradyi.._____________________________ 44 

Pye, W. D., cited .. -------------------------- 13 

Q 

Quartz, authigenic ... ------------------------- 86 

Quenstedt, Werner, cited_____________________ 56 

Quick, G. L. See Peterson, N. P. 

R 

Radiina. __ . __ -------------------------------. 99 

Radiosphaera. __ ------ ___ --------------------- 99 

Rakhmanova, S. G., cited____________________ 99 

Ransome, F. L., cited ____ a, 6, 9, 12, 13, 14, 24, 25,26 

Rastall, R. H. See Hatch, F. H. 

Reagan, A. B., cited__________________________ 6, 58 

Reber, L. E., 12, cited _______________________ 6, 12,26 

References cited_-------- _______ -------------- 169 

Reis, 0. M., cited .. -------------------------- 102 Reitlinger, E. A., cited. _________________ 99,100,102 

Reynolds, S. H., cited________________________ 99 

Rhizocorallium ________________________________ 53,66 

Rhynia. _ ------------------- ______ ------------ 89 

Richter, Rudolf, cited--------------~--------- 26,67 

Richthofenia. _ .. ------------------------------ 105 

Ripple marks. ____ --------------------------- 31,47 

Rittenberg, S.C. See Emery, K. 0. 

Robertson, E. C. See Hathaway, J. C. 

Robinson, H. H., cited_______________________ 8,12 

Rodgers, John, cited.-----------------------.. 74 

See Dunbar, C. 0. 
180 

Page 

Rove, 0. N. See Goddard, E. N. 

Rukhin, L. B., cited ______________________ 41,76,80 

s 

Sabins, F. F., Jr., cited_______________________ 13 

St. Johns Sag ________________________________ _ 

Salt River asbestos mine, Beckers Butte Member, contact with Jerome_________ 25 

Jerome Member, brown rind chert______ 38 

measured section at_ ___ ------------------ 109 

Salt River Bridge, Beckers Butte Member, as 

channel filL---------------------- 24 

Beckers Butte Member, transitional beds_ 25 

sample listings________________________ 27 

measured section near __ ------------------ 111 

Salt River Draw, measure sections in------- 111,113 

Sandberg, C. A., cited ________________________ 29,89 

Sandstone, Beckers Butte Member ________ 16, 17,29 

Jerome Member-----------------~-------- 25,73 

aphanitic dolomite unit_ _______ 33,37,99,83 

upper uniLA4, 45, 47, 50, 51, 52, 53, 55, 73, 85 

Sawmill Creek, outcrops near ___ .. ____________ 5 

Sawmill Road, measured section along _______ 105 

Schlifer, Wilhelm, cited ___________________ .. ___ 82 

Scheifele, Kathleen. See Cross, J. L. 

Schenck, H. G., and Graham, J. J., cited ____ 10 

Schieltz, N.C. See LeRoy, L. W. 

Schizophoria_ ------------------ 51, 52, 54, 55, 61, 91,92 

Schizophoria iowensis ________________ 49, 58, 60, 90, 92 

Schizosphaerella_____________ __________ ___ _____ 105 

Schmidt, Hermann, cited____________________ 56 

Schopf, J. M. See Teichert, Curt. 

Scope of investigations_______________________ 9 

Seeliger, Robert, cited------------------------ 76 

Seilaeher, Adolf, cited------------------------ 67 

Sevenmile Creek, Jerome Member, brown rind 

chert __ --------------------------- 38 

measured section along___________________ 167 

Shale, Beckers Butte Member ________________ 24,25 

in aphanitic dolomite unit_ _______________ 33,39 

in upper unit__ _____________________ 47, 53, 55,85 

Shapiro, Leonard, and Brannock, W. W., 

cited_---------------_____________ 10 

Sharp Creek, measured section along_________ 131 

Shaw, E. H. See Cross, J. L. 

Short, M. N., Galbraith, F. W., Harshman, 

E. N., Kuhn, T. H., and Wilson, 

E. D., cited---------------------- 13,38 

Shride, A. F. See Bromfield, C. S. 

Shride, A. F., McKee, E. D., and Harshbarger, 

J. W., cited_______________________ 23 

Shrock, R. R., cited __________________________ 20,82 

Shrock, R. R., and Twenhofel, W. H., cited_ 55 

quoted ___ -------------------------_______ 61 

·shvetsov, M. S., cited________________________ 83 

Siever, Raymond, cited---------------------- 73 

Silica, in aphanitic dolomite unit_ _________ 36, 37,38 

in fetid dolomite unit_____________________ 30 

Singewald, J. T. See Goddard, E. N. 

Somerville, J. L. See Woolnough, W. G. 

Southern Arizona, stratigraphic nomenclature_ 12 

Spathognathodus sp___________________________ 44 

Sphaerella __________ ------------ _ __ _____ ______ 99 

Spinatrypa ___ ----------------------- 51, 52, 60, 91,92 

Spinatrypa albertensis_________________________ 58 

rotunda __ -------------------------- 49, 54, 58,90 

Spirijer argentarius _ -------------------------- 91 

fornacula ___ ----------- _ ------------------ 6 

strigosus __ -------------------------------- 92 

Spongophyllum_ ------------------------------ 51,58 

Spongophyllum martinense____________________ 58 

sp __ -- _________________________ --- _ _ _ _ _ _ _ _ 58 

Spring Canyon, measured sections in_________ 117 

Squaw Peak, section near_-------------------

Squaw Peak mine, measured section at_______ 160 

Stauffer, C. R., cited----------------------- 7, 13,15 

INDEX 

Steidtmann, Edward, cited __________________ _ 

Stelck, C. R. See Warren, P. S. 

Page 

71 

Stenoscisma SP-------------------------------- 58 

Stevenson, F. V., cited_______________________ 90 

Stictostroma ______ ----------------------------- 54, 57 

Stictostroma sp________________________________ 51 

Stomiosphaera ____ -------------------------- __ 99 

Storz, Max, cited __________________________ 39, 86,87 

Stoyanow, A. A., cited .. ___ 7, 8, 9, 12, 13, 14, 15, 17, 26, 

29, 33, 40, 43, 44, 45, 47, 57, 61, 64,97 

paleogeographical conclusions by_________ 7 

Straaten, L. M. J. U. van, cited______________ 82 

Strackhov, N. M., cited ________________ 39,41, 74,76 

Strahan, Aubrey, Tiddeman, R. H., Gibson, 

W., Dixon, E. E. L., and Jones, 

0. T., cited _____________________ _ 39 

Stratigraphic section, Black River____________ 106 

Boy Scout Ranch No.!__________________ 133 

Chasm Creek _______ --------------------- 159 

Christopher Creek_______________________ 133 

Christopher Czeek Camping Area________ 133 

Christopher Mountain Ridge ____________ ~ 129 

Diamond Point ___ ----------------------- 140 

Doubtful Creek _______ ---------------____ 133 

east side of Canyon Creek ______________ 114,124 

East Verde RiveL_______________________ 144 

Elden Mountain __ ----------------------- 165 

Flying V Canyon_----------------------- 107 

Huntez Creek____________________________ 131 

Hunter and Sharps Creeks_______________ 131 

Jerome _____________ ---------------------- 161 

Kohl Ranch______________________________ 136 

Limestone Hills_------------------------- 157 

Lost Tank Canyon_______________________ 118 

Mormon Tank___________________________ 168 

Naeglin Rim_____________________________ 125 

Oak Creek Farm Road___________________ 116 

Pinal Creek______________________________ 152 

Salt River asbestos mine_---------------- 109 

Salt River Draw (north section)__________ 113 

Salt River Draw (south section)__________ 111 

Savnnill Road____________________________ 105 

Sevenmile Creek __ ----------------------- 167 

south of Iron King mine__________________ 166 

south of Salt River Bridge________________ 111 

south of Turkey Peak_------------------- 128 

southwest branch of Lost Tank Canyon__ 121 

Spring Canyon___________________________ 117 

Squaw Peak mine________________________ 160 

Theodore Roosevelt Dam________________ 153 

Thompson Wash_________________________ 138 

Tonto and Horton Creeks________________ 135 

Tonto Natural Bridge____________________ 148 

Upper Concord Canyon__________________ 127 

Upper Hull Canyon______________________ 163 

Upper Sycamore Canyon_________________ 145 

Verde River at Sycamore Creek__________ 163 

Webber Creek____________________________ 142 

west bank of Canyon Creek_------------- 122 

west of Christopher Ranch_______________ 132 

Windy HilL____________________________ 155 

Striatopora sp________ _________ ___ _ ___ ____ ___ __ 58 

Stringophyllum __ ----------------------------- 49 

Stringophyllum sp __ -------------------------- 58 

Stromatopora _________ ------------------ ______ 43 

Stromatoporoids______________________________ 57 

Struve, Wolfgang. See Hotz, E. E. 

Stumm, E. C., cited._________________________ 90 

Styliolina ___ __________________________________ 51, 63 

Stylolites___________________________________ 48 

Subunit, defined_____________________________ 10 

Sweeting, G. S., cited__ _____________________ 72 

Sycamore Canyon, Upper, measured section 

in________________________________ 145 

Sycamore Creek, measured section at Verde 

River ____________ -------------____ 163 

Sycamore Creek Sandstone___________________ 14 

Page 

Synprioniodina sp ___ ------------------- ______ 44 

Syringopora _______ ____________________________ 43, 47 

Syringopora SP-------------------------------- 58 

T 

Tabellaephyllum peculiaris _________________ 53, 58,90 

Tabulophyllum __ ----------------------- 43, 51, 91,92 

Tabulophyllum sp ___ ---------------------- 43, 58,90 

Tacsh, Paul, cited____________________________ 56 

Talent, J. A. See Teichert, Curt. 

Tapeats Sandstone___________________________ 26 

Tapeats Sandstone, burrows in_______________ 26 

heavy-mineral suites in___________________ 26 

Taphocoenosis, defined_______________________ 56 

Tappen, Helen. See Loeblich, A. R., Jr. 

Taylor, J. M., cited__________________________ 73 

Tectonic setting______________________________ 3 

Teichert, Curt, cited_________________________ 78 

See Clarke, E. de C. 

TeicheJt, Curt, and Schopf, J. M., cited __ 9, 21, 29,89 

quoted __ ------------------------- ________ 21,22 

Teichert, Curt, and Talent, J. A., cited_______ 57 

Temple Butte Limestone_____________________ 12 

Ten Haat, E. See Kuenen, Ph. H. 

Tenticospirijer ________________________________ 65,92 

Tenticospirijer cyrtinajormis ___________________ 58,92 

Teodorovich, G. I., cited_____________________ 41 

Thamnopora _______ 43, 44, 47, 49, 50, 51, 58, 61, 66, 84,92 

Thamnopora sp ______________________ 44, 49, 51, 58,90 

Thanatocoenosis, defined and discussed_______ 56 

Theodore Roosevelt Dam, Beckers Butte 

Member, gradational unit________ 25 

measured section at_______________________ 153 

section at_________________________________ 6, 54 

Theodore Roosevelt Lake, Beckers Butte 

Member, exposed as channel filL_ 24 

Theodossia ___________ -------------------- __ 47, 53,65 

Theodossia hungerfordi_ ______________ 51, 52, 58, 59,90 

sp ________________________________________ 52,92 

Thickness, Martin Formation and its subdivisions_________________________ 20 

Thomas, H. D., cited_________________________ 102 

Thompson Wash, fish-plate costs at__ _ _ _ _ _ _ _ _ 40 

Jerome Member, aphanitic dolomite unit, 

marginal facies of.. _____________ 37, 40,48 

aphanitic limestone unit, marginal 

facies oL_____________________ 40 

measured section in_______________________ 138 

Thomson, Alan, cited________________________ 73 

Tiddeman, R. H. See Strahan, Aubrey. 

Timanites _ ___ _ __ _ __ _ ___ __ _ ___ _ _ _ _ _____ __ ___ _ _ 92 

Timofeev, P: P. See Botvinkina, L. N. 

Tintinnids_-------------------- _____ 49, 53, 54, .57, 66 

Tintinnina_ _ ____ ____ __ _ __ __ _ __ _ _ __ ___ _ _____ __ 97 

Tintinnopsella __ -- ____ -- _. __ -- _ ___ _ __ _ __ _ _ _ __ _ 99 

Tonto and Horton Creeks, Jerome Member, 

aphanitic limestone unit, marginal facies oL _________________________ 40,48 

Jerome Member, fetid dolomite unit 

missing ___________________________ 37, 48 

Tonto Creek, measured section along_________ 135 

Tonto Natural Bridge________________________ 45 

Tonto Natural Bridge, measured section at___ 148 

Topkaya, Mehmed, cited_____________________ 86 

Trails, invertebrate _____________________ 33, 40, 43,66 

Trask, P. D. See Goddard, E. N. 

Turkey Peak, measured section near_________ 128 

Turner, D. S., cited __________________________ 8,86 

Tusayana cibola_______________________________ 62 

Twenhofel, W. H. See Shrock, R. R. 

Tyrrell, G. W., cited_________________________ 74 

u 

Umbella ____ ----------- 18, 40, 47, 48, 57, 85, 90, 100, 103 

Umbella baschkirica___________________________ 104 

bella _____________________________________ 91,104 
Umbellina ______ ----------------------- ______ _ 

Upper Hull Canyon, Jerome Member, fossiliferous dolomite beds __________ _ 

Tapeats Sandstone, similarity to top of 

Beckers Butte Member __________ _ 

Upper Sycamore Canyon, Beckers Butte 

Page 

104 

43 

26 

Member, contact with Jerome____ 25 

Upper unit, Jerome Member, area southeast of 

Jerome ___________ ---------------- 44 

Jerome Member, depositional history_____ 84 

detrital quartz in ______ --------------_ 45,47 

dolomitization________________________ 85 

facies west and north of Jerome_______ 43 fossils in _____________________ 42, 43, 47, 49,55 

intraformational disconformities in___ 48 

middle Canyon Creek to upper Salt 

River_____________________________ 51 

northeastern onlap belL-------------- 47 

paleoecology ____ --- ___ - _____ ----- __ --- 55 

Pine Creek area______________________ 45 

Roosevelt-Globe area_________________ 54 silica in_______________________________ 85 

thickness--------------------------- 19, 20,42 

type section_------------------------- 4$ upper East Verde River area_________ 45 

v VanHise, C. R., cited________________________ 80 

See Irving, R. D. 

INDEX 

Page 

Vatan, Andrli, cited-------------------------- 20 

Veevers, J. J., cited___________________________ 9!1 

Verde River, Jerome Member, fossiliferous 

beds______________________________ 44 

measured section at Sycamore Creek______ 163 

Tapeats-Jerome contact__________________ 43 

Vishnyakov, S. G., cited ___ ------------------ 41,76 

w 

Walcott, C. D., cited_________________________ 12 

Walker, T. R., cited----------------------- 39,83,86 

Walther, Johannes, cited ______________________ 74,78 

Wanless, H. R., Ziebell, W. G., Ziemba, E. A., 

and Carozzi, A., cited ___ ------------------- 72 

Wanner, Johannes, cited-------------------- 99,102 

Wanen, L. E. See Barnes, V. E. 

Warren, P. S., cited__________________________ 91 

Warren, P. S., and Stelck, C. R., cited _______ 91,92 

Wasmund, Erich, cited ______ ----------------- 56 

Webber Creek, Beckers Butte Member, carbonate component oL____________ 25 

Beckers Butte Member, transitional beds_ 25 

Jerome Member, limestcne_______________ 37 

measured section along____________________ 142 

Webster, C. L., cited _______ ------------------ 90 

Weller, J. M., cited-------------------------- 11 

Wheeler, G. M., cited ______ ·----------------- 6 

181 

Page 

Williams, J. S., cited------------------------- 12,89 

See Nolan, T. B. 

Williamson, W. C., cited---------------- 99,100, 102 

Wilson, E. D. See Darton, N.H. 

See Lausen, Carl. 

See Short, M. N. 

Wilson, E. D., and Moore, R. T., cited_______ 3 

Wilson, E. D., and others cited _______________ 6,55 

Windy Hill, Jerome Member, aphanitic dolomite unit, sandstone subunit_____ 39 

measured section at __ -------------------- 155 

section at_________________________________ 7 

Wolfenden, E. B., cited---------------------- 99 

Wood, Alan, cited____________________________ 31 

Woolnough, W. G., and Sommerville, J. L., 

cited _____ ------------------- __ --- 72 

y 

Yablokov, V. S. See Botvinkina, L. N. 

z 

Zen, E-An, cited----------------------------- 83 

Zhemchuzhnikov, Yu. A. See Botvinkina, 

L.N. 

Ziebell, W. G. See Wanless, H. R. 

Ziemba, E. A. See Wanless, H. R. 

U.S. GOVERNMENT PRINTING OFFICE: 1965 0-745-106 

PLAT~~S 1-21 

Every individual photograph having an enlargement of X 25 or less is marked by a 

black or white bar indicating the length of 1 mm in the scale of the illustration. Unless 

the illustration is described as "unoriented" in the explanation, the photograph is oriented 

so that the bar lies parallel to the bedding plane and the direction upward from and perpendicular to the bar is also the direction upward in the rock. The number in parentheses 

at the end of the figure description-for ex.!lmple ( T-220) -is the sample number. Points 

marked by intersection of lines projected from points AA, BB, CC, or DD (for example, 

fig. 2 of pl. 17) indicate items discussed in ·:he text. 
PLATE 1 

FIGURE 1. Sandstone containing a considerable amount of calcareous cement. Beckers Butte Member. Section 12, Lost 

Tank Canyon. X 12.5. (T-220) 

2. Sandstone with calcareous cement. Basal part of Beckers Butte Member. Section 2, Black River, subunit 1. 

X 12.5. (T-54.) 

3. Sandstone. Detrital grains are composed mostly of quartz and a small amount of chert and feldspar. The cement 

is clay. Beckers Butte Member. Section 30, Diamond Point, subunit 5. X 12.5. (H56-190.) 

4. Dolomitic microbreccia. Fetid dolomite unit of Jerome Member. Section 2, Black River, subunit 2. X 9. (T56-247.) 

5. Very fine grained dolomite having microlamination and intrastratal erosion. Fetid dolomite unit of Jerome Member. 

Section 39, Chasm Creek, subunit 6. X 15. (H56-252.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 1 

3 5 

ROCKS OF THE BECKERS BUTTE MEMBER AND THE FETID DOLOMITE UNIT OF JEROME MEMBER 
PLATE 2 

FIGURE 1. Very fine grained dolomite having thin opaque laminae. Section 4, Salt River, subunit 2. X 25. (T56-285.) 

2. Aphanitic thinly laminated limestone. Section 31, Webber Creek, subunit 15. X 25. (T56-512.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 2 

2 

ROCKS OF THE FETID DOLOMITE UNIT OF THE JEROME MEMBER 

74!i-1()6 (}---64-9 
PLATE 3 

FIGU.RE 1. Very fine grained clotty limestone, indistinctly laminated. Same locality and rock subunit as figure 2 of plate 

2. X 25. (T56- 512.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 3 

I 

ROCK OF THE FETID DOLOMITE UNIT OF THE JEROME MEMBER 
PLATE 4 

FIGURE 1. Very fine grained dolomite and irregular layers of aphanitic dolomite. Section 34, Tonto Natural Bridge, subunit 3. 

X 15. (T56- 468.) 

2. Silica-impregnated aphanitic dolomite breccia (for description see p. 39). Section :39, Chasm Creek, subunit 9. X 15. 

(H56-255a.) 

3. Aphanitic dolomite containing two kinds of differently colored intraclasts and having an extensively recrystallized matrix. 

Section 39, Chasm Creek, subunit 12. X 15. (H56-259.) 

4. Intraclastic subaphanitic dolomite. Clasts range 0.05 to 2 mm in diameter and are more finely aphanitic than matrix. 

Lower part of unit. Section 37, Windy Hill, subunit 3. X 15. (H56-344.) 

5. Chert-impregnated fine-grained dolomite. Section 36, Roosevelt, subunit 10. All large and small white areas are chert. 

X 12.5. (H56- 68.) 

6. Aphanitic dolomite breccia; fractures are filled with finely crystalline dolomite. Section 3, Flying V Canyon, subunit 

20. X 15. (H56-51.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 4 

~ . . • . \1 

- ~,:: 

3 

5 

ROCKS OF THE APHANITIC DOLOMITE UNIT OF THE JEROME MEMBER 
PLATE 5 

FIGURE 1. Aphanitic limestone, primarily intraclastic, partially recrystallized. Section 34, Tonto Natural Bridge, subunit 15. 

X 15. (T56-479.) 

2. Aphanitic dolomite containing a large cavity tilled with spherulitic quartz, which is marginally replaced by dolomite. 

The large white area is spherulitic quartz; the black area surrounding it is aphanitic dolomite; the gray cloudy belts at 

the margins of the quartz area are aphanitic dolomite, which is more transparent than the original dolomite rock. The 

smaller irregularly shaped gray areas scattered across the specimen are crystalline dolomite. Section 39, Chasm 

Creek, subunit 10. X 15. (H56- 258.) 

3. Aphanitic dolomite having indistinct primary lamination and containing secondary calcite (white patches). Section 37, 

Windy Hill, subunit 3. X 15. (H56-343.) 

4. Aphanitic dolomite containing detrital quartz grains (white), small aphanitic dolomite clasts (dark), and recrystallized 

dolomite clasts. Section 38, Limestone Hills, subunit 13. X 9. (H56-328.) 

5. Fine-grained to very fine grained dolomite containing a calcite vug. The dark area in center is one single calcite crystal 

(stained) . Section 33, Upper Sycamore Canyon, subunit 10. X 15. (H56- 227.) 

6. Very fine grained sandstone. The dark patches are dolomitic cement. Section 37, Windy Hill, subunit 5. X 9. (H56-

::146.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 5 

3 

5 

ROCKS OF THE APHANITIC DOLOMITE UNIT OF THE JEROME MEMBER 
PLATE 6 

FIGURE 1. Aphanitic dolomite thoroughly impregnated with microcrystalline silica and containing silicified shells of calcispheres. 

Dark-gray areas are dolomit~; light-gray and white areas arc silica. Top of unit. Section 4, Salt River, subunit 8. X 

9. (T56-293b.) 

2. Aphanitic limestone containing ostracodes (Hypotetragona sp.). Upper part of unit. Section 32, East Verde River, 

subunit 22. X 12X. (T-317.) 

3. Fossiliferous dolomite. The dark groundmass is aphanitic dolomite; the white areas are crystalline dolomite. Note 

outlines of small ostracodes in lower right corner and shell fragments scattered throughout most of specimen. Section 8, Canyon Creek, subunit 5. X 30. (H56-40.) 

4. AphaniLic dolomite containing thoroughly recrystallized, dolomitic calcispheres. Top of unit. Section 41, Jerome, 

subunit 14. X 22.5. (H56- 285.) 

5. Aphanitic dolomite containing authigenic spherulitic quartz. Section 38, Limestone Hills, subunit 8. X 15. Crossed 

nicols. (H56-317.) Unoriented. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 6 

2 

3 

4 5 

ROCKS OF THE APHANITIC DOLOMITE UNIT OF THE JEROME MEMBER 
PLATE 7 

FIGURE 1. Aphanitic dolomite containing much detrital quartz. Some of the matrix has been recrystallized into crystalline dolomite, 

and almost all quartz grains have thin rims of very fine grained dolomite. Aphanitic dolomite unit. Section 28, Kohl 

Ranch, subunit 14. X 9. (H56-156.) 

2. Aphanitic limestone containing scattered dolomite rhombohedra, doubly terminated authigenic quartz crystals, thinwalled calcispheres, and unidentified fossil debris. Upper unit. Section 34, Tonto Nat ural Bridge, subunit 21. X 60. 

(T56- 487.) Same thin section as shown in plate 11, figure 5. 

3. Calcitic dolomite, very sandy. Groundmass composed of coarse, anhedral dolomite crystals and abundant detrital 

quartz. Quartz grains only slightly etched. Upper unit. Section 34, Tonto Natural Bridge, subunit. 32. X 12.5. 

(T56- 494.) 

4. Dolomite. Light parts consist of crystals 20-50 microns in diameter; dark parts of crystals are less than 20 microns in 

diameter. Lower part of upper unit. Section 41 , Jerome, .subunit 24. X 12.5. (H56-311.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 7 

' 

2 

3 4 

ROCKS OF THE APHANITIC DOLOMITE UNIT AND THE UPPER UNIT OF THE JEROME MEMBER 
PLATE 8. 

FIGURE 1. Aphanitic limestone containing scattered dolomite rhombohedra, detrital quartz, and organic debris. Cross section of 

brachiopod spine located just below center; cross sections of echinoid spines occur in upper left and lower left quadrants; 

several cross sections of shells of punctate brachiopods are shown. Section 38, Limestone Hills, subunit 18. X 22.5 

(H56-330.) 

2. Slightly calcitic saccharoidal dolomite and interstitial calcite. White : primary pores. Dark lines between dolomite 

crystals: calcite (stained) . Section 43, Verde River at Sycamore Creek, subunit 18. X 22.5. (T56- 557.) 

3. Fine-grained dolomite containing "ghosts" of dolomite clasts and microfossils (calcispheres?). Lower part of unit. Section 41, Jerome, subunit 20. X 15. (H56-308.) 

4. Calcitic dolomite, very sandy. Dark-gray areas are calcite (stained); each patch has the properties of a single crystal. 

Section 34, Tonto Natural Bridge, subunit 19. X 15. (T56-485.) 

5. Aphanitic limestone and a large area (white to light gray) composed of crystalline calcite (recrystallized), scattered 

dolomite rhombohedra, doubly terminated authigenic quartz crystals, and fragmental microfossils, including thinwalled calcispheres; cross section of Amphipora is shown slightly below the center. Section 34, Tonto Nat ural 

Bridge, subunit 21. X 15. (T56-487.) Same thin section as that shown in plate 7, figure 2. 

6. Microstylolite in very fine grained dolomite. Section 29, Thompson Wash, subunit 12. X 15. (T57-388.) 
GEOLOGICAL SURVEY 

3 

5 

PROFESSIONAL PAPER 464 PLATE 8 

2 

4 

6 

ROCKS OF THE UPPER UNIT OF THE JEROME MEMBER 
FIGURE 1. 

2. 

3. 

4. 

5. 

6. 

7. 

PLATE 9 

Sandy calcitic dolomite. Black: calcite (in extinction position); gray: dolomite rhombohedra, variously oriented; white: 

detrital quartz. Section 38, Limestone Hills, subunit 31. X 9. Crossed nicols. (H56- 331.) Unoriented. 

Dolomitic limestone. Dark gray: aphanitic limestone matrix; lighter gray: dolomite rhombohedra and quartz silt. 

Top of unit; section 27, Tonto and Horton Creeks, subunit 20. X 12.5. (T57-370.) 

Slightly calcitic dolomite: mixture of anhedral and euhedral dolomite crystals, interstitial calcite, and very little detrital 

quartz. Section 34, Tonto Natural Bridge, subunit 37. X 15. (T56- 496.) 

Slightly calcitic arenaceous dolomite. The two large quartz grains on the left and the right sides of the figure are extensively replaced by dolomite and have entirely lost their original outlines. Section 34, Tonto Nat ural Bridge, subunit 

43. X 22.5. (T56- 502.) 

Sutured grain contacts in thin-bedded sandstone containing invertebrate trails. Near base of unit; section 6, Salt River 

Draw, subunit 15. X 22.5. (T-101.) Unorientcd. (The gray bands cutting across grains in upper left quadrants 

are pencil marks.) 

Medium-grained sandstone containing specimen of Umbella? sp. near center. Lower part of unit: section 27, Tonto and 

Horton Creeks, subunit 8. X 22.5. (T57-356.) Unoriented. 

Dolomitic sandstone having a finely crystalline dolomite matrix in which "ghosts" of pellets or clasts can be recognized. 

(See especially in upper left quadrant.) Detrital qua,rtz grains have considerable overgrowth and little etching. Section 28, Kohl Ranch, subunit 26. X 15. (H56- 175.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 9 

2 

3 4 

6 

5 7 

ROCKS OF THE UPPER UNIT OF THE JEROME MEMBER 
PLATE 10 

FIGURE 1. Calcitic arenaceous dolomite. Interstitial calcite between dolomite crystals, emphasized by staining, and moderate 

amount of peripheral dolomite replacement of quartz grains are shown. Section 22, west of Christopher Creek Ranch, 

subunit 4. X 15. (T57-379.) 

2. Luster mottled dolomite. Partly interpenetrating groups of dolomite crystals having identical optical orientation within 

each group are shown. Crossed nicols. Section 22, west of Christopher Creek Ranch, subunit 2. X 15. (T57-378.) 

3. Dolomite. The aphanitic matrix is recrystallized mostly into finely crystalline aggregate. Calcispheres are preserved 

in parts of the aphanitic matrix. Section 16, Naeglin Rim, subunit 7. X 8. (T56-412.) 

4. Limestone. Dark: aphanitic limestone, granular; translucent: crystalline calcite. White: detrital quartz. Note near 

absence of quartz grains in areas of crystalline calcite. Section 9, Oak Creek Farm Road, subunit 9. X 15. (T-184.) 

Unoriented. 

5. Medium-grained sandstone. Almost all grain contacts are diagenetic; overgrowth is moderate. Base of unit; section 

16, Naeglin Rim, subunit 1. X 12.5. (T56- 405.) 

6. Saccharoidal dolomite consisting of two distinct size groups of dolomite crystals. Upper part of unit; section 18, south 

of Turkey Peak, subunit 17. X 15. (H56-147.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 10 

2 

3 4 

6 

ROCKS OF THE UPPER UNIT OF THE JEROME MEMBER FROM VICINITY OF ONLAP BELT 
PLATE 11 

FIGURE 1. Dolomite breccia. Some of the minute fissures are calcite-filled; the indistinct ovoid and ellipsoidal shapes in lower 

left quadrant may be calcispheres. Section 16, N aeglin Rim, subunit 6. X 8. (T56-409.) 

2. Arenaceous saccharoidal dolomite. The dolomitic matrix (gray) and detrital quartz (white) are about equal in grain 

size. Upper part of unit; section 18, south of Turkey Peak, subunit 17. X 22.5. (H56-148.) 

3. Very fine grained dolomite containing rounded quartz grains surrounded by halos of slightly more coarsely crystalline 

translucent dolomite. Section 16, Naeglin Rim, subunit 6. X 8. (T56-409.) 

4. Dolomite consisting of aphanitic matrix and (darker) aphanitic clasts and containing much detrital quartz, mostly of 

silt and fine-sand size. The three largest grains in the picture are quartz (top), chert (lower left), and aphanitic dolomite (lower right). Large grains and some smaller ones are surrounded by halos of finely crystalline dolomite; the 

dolomite also partly replaces the aphanitic matrix between grains. Lower part of unit; section 18, south of Turkey 

Peak, subunit 1. X 15. (H56-136.) 

5. Arenaceous aphanitic limestone that is very finely intraclastic and contains much detrital quartz. Near top of unit; 

section 15, 1 mile south of 0. W. Ranch, subunit 23. X 12.5. (T56-370.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 11 

2 

ROCKS OF THE UPPER UNIT OF THE JEROME MEMBER FROM VICINITY OF ONLAP BELT 
PLATE 12 

FIGURES 1, 2. Photographs of different parts of one thin section. Figure 1 shows the original nature of the rock which is an aphanitic limestone consisting of a light colored groundmass, dark-colored small intraclasts, some silt-size detrital 

quartz, a.nd a few dolomite rhombohedra. Figure 2 shows the same rock almost completely replaced by dolomite 

rhombohedra. Section 12, Lost Tank Canyon, subunit 35. X 15. (T56- 397.) 

3. Arenaceous calcitic dolomite. A considerable amount of peripheral dolomite replacement of quartz grains is shown. 

Channel fill ; section 14, 2 miles south of 0. W. Ranch, subunit 4. X 15. (H56-105.) 

4. Calcitic sandstone. This specimen is from a portion of the rock that has more cement than sand grains. The cement is recrystallized into crystal grains several millimeters in diameter. Quartz grains show some peripheral 

calcite replacement. Section 9, Oak Creek Farm Road, subunit 19. (T-193.) Unoriented. 

5. Fine-grained sandstone, many grains of which have considerable overgrowth. The specimen was collected near the 

onlap belt. Section 9, Oak Creek Farm Road, subunit 6. X 9. (T- 182.) Unoriented. 

6. Limestone, originally aphanitic, now largely recrystallized. Calcispheres are abundant in both the aphanitic rock 

and the recrystallized matrix. Upper part of unit near onlap belt; section 4, Salt River, subunit 18. X 15. 

(T56-308U.) 
GEOLOGICAL SURVEY 

1 

5 

PROFESSIONAL PAPER 464 PLATE 12 

2 

4 

6 

ROCKS OF THE UPPER UNIT OF THE JEROME MEMBER 
PLATE 13 

FIGURE 1. Aphanit.ic limestone containing pteropods (St.yliolina?), calcispheres, and unidentified objects. Section 9, Oak Creek 

Farm Road, subunit 12. X 9. (T-187 A.) Unoriented. 

2. Dolomitic limestone. The groundmass is composed of aphanitic limestone and contains abundant calcispheres, tintinnids 

(?),and unidentified fragmental fossils; about half of the rock is replaced by authigenic dolomite rhombohedra. (Sec 

also pl. 16.) Lower part of unit; Section 6, Salt River Draw, subunit 18. X 15. (T- 105.) Unoriented. 

3. Saccharoidal dolomite, very impure. The matrix consists of a mixture of anhedral and euhedral dolomite crystals having 

greatly varying sizes; some specimens show good lamellar texture. Much finecgrained detrital quartz and clay is 

distributed through the dolomite. In the center and lower right of the figure are "ghosts" of sedimentary structures. 

Section 1.5, 1 mile south of 0 . W. Ranch, subunit 3. X 15. (T56-352.) 

4. Same rock as illustrated in figure 2, containing fewer dolomite crystals, some large and small thin-walled calcisph eres, 

and other fossil debris. One calcisphere is partly replaced by a dolomite crystal. Section 6, Salt River Draw, subunit 18. X 22.5. (T-105.) Unoriented. 

5. Calcareous sandstone, fine grained. Grain contacts are partly sedimentary but mostly diagenetic. Dark areas between 

grains are calcareous cement. Section 12, Lost Tank Canyon, subunit 38. X 12.5. (T56-400). 

6. Fragmental limestone composed mostly of recrystallized calcispheres and aphanitic limestone clasts. The more homogeneous areas shown near the center a nd lower left of the figure are recrystallized echinoderm fragments. The space 

between individual clasts or other fragments is filled with crystalline calcite. Section 11, Spring Canyon, subunit 3. 

X 20. (T-166.) Unorientecl. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 13 

1 

ROCKS OF THE UPPER UNIT OF THE .JEROME MEMBER 
PLATE 14 

FIGURE 1. Dolomite having luster mottling. Two partly interpenetrating groups of dolomite crystals having parallel optical orientation within each group are shown. Uppermost part of Beckers Butte Member; section 31, Webber Creek, subunit 11. 

X 15. (T56-510.) Crossed nicols. 

2. Cross section of a partly silicified brachiopod shell in limestone. The light-colored rim of the shell is composed of microcrystalline chert; the gray area inside is calcite. Upper unit of J erome Member; section 6, Salt River Draw, subunit 

28. X 12.5. (T- 142.) 

3. Sandstone, highly calcareous. Matrix consists of fine-grained limestone and numerous small aphanitic limestone clasts 

(black). Upper unit of Jerome Member; section 36, Roosevelt Dam, subunit 15. X 15. (H56-81.) 

4. Saccharoidal, calcitic dolomite. Calcitic matrix is crystallized in areas having a single crystal structure, which are distinguished by different shades of gray; poikilitically enclosed dolomite rhombohedra are in random orientation. Upper 

unit of Jerome Member; section 44, Elden Mountains, subunit 2. X 9. (T56- 575.) Crossed nicols. 

5. Fine-grained luster-mottled sandstone. In the right half of the figure, three dark areas of calcareous matrix (extinction 

position) occur, whereas in the left half of the figure, calcareous matrix forms one light-colored area. Upper unit of 

Jerome Member; section 11, Spring Creek, subunit 4. X 9. (T-167.) Unoriented. Crossed nicols. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 14 

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4 

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LUSTER MOTTLED ROCKS AND SILICIFICATION 

().6 0-64.-----10 
PLATE 15 

FIGURE 1. Fine-grained sandstone containing chert granule in center. All grain contacts are diagenetic. Lower part of upper 

unit of Jerome Member; section 36, Roosevelt Dam, subunit 19. X 12.5. (H56-84.) 

2. Silicified coral in unpolarized light. The septa and dissepiments are clearly shown. Top of upper unit of Jerome Member; section 20, Hunter Creek. X 9. (T-301.) 

3. Aphanitic limestone containing a large recrystallized area. In the upper part of the recrystallized area is an outline of a 

thick-walled calcisphere, possibly Umbella. The specimen was collected from the Martin Limestone, about 40 feet 

above the base. Mount Martin, near Bisbee, Ariz. X 22.5. (T56-319.) Unoriented. 

4. Same specimen as shown in figure 2, photographed between crossed nicols to show aggregate of quartz crystals. X 9. 

5. Thick-walled calcisphere, possibly having a recrystallized internal structure. Upper part of aphanitic dolomite unit 

of Jerome Member; section 6, Salt River Draw, subunit 10. X 75. (T-98.) 

6. Specimen of Umbella(?) in dolomitic sandstone. The wall has a well-preserved fibrous texture. Upper unit of Jerome 

Member; section 27, Tonto and Horton Creeks, subunit 8. X 45. (T57-356.) Unoriented. 
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PROFESSIONAL PAPER 464 PLATE 15 

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SILICIFICATION, CALCISPHERES, TINTINNIDS(?) 
PLATE 16 

F IGURE 1. Dolomitic limestone. The groundmass is composed of aphanitic limestone; the rock contains tintinnid(?) (upper part 

of figure), thin-walled calcispheres, and unidentified objects and debris. Part of the rock is replaced by authigenic 

dolomite rhombohedra. (See also pl. 13, figs. 2 and 4.) Upper unit of Jerome Member; section 6, Salt River Draw, 

subunit 18. X 56. (T-105.) Unoriented. 

2. Limestone, very finely crystalline, containing possible tintinnids (one longitudinal and one transverse section near center), 

ostracodes, and unidentified fossil debris. Upper unit of Jerome Member; section 17, Colcord Canyon, subunit 17. 

X 30. (T56-443.) 

3. Aphanitic limestone, partly recrystallized, containing two thick-walled calcispheres, also recrystallized (possibly Umbella). 

Martin Limestone, about 40 feet above the base; Mount Martin, near Bisbee, Ariz. X 30. (T56-319.) Unoriented. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 16 

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CALCISPHERES, TINTINNIDS( ?) 
PLATE 17 

FIGURE 1. Limestone, very fine grained, containing abundant calcispheres, some unidentified shell fragments-probably ostracodesand scattered dolomite rhombohedra. Upper unit of Jerome Member; section 9, Oak Creek Farm Road, subunit 10. 

X 30. (T-185.) Unoriented. 

2. Very fine grained limestone containing many thin-walled calcispheres, ostracodes, and unidentified fossil debris. Upper 

unit of Jerome Member; section 17, Colcord Canyon, subunit 17. X 45. (T56-443.) Unoriented. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 17 

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t t t 2 

B D c 

CALCISPHERES, OSTRACODES 
PLATE 18 

FIGURE 1. Aphanitic limestone containing many thin-walled calcispheres and unidentified fossil fragments. The large recrystallized 

areas are cross sections of either Amphipora or Thamnopora colonies. Upper unit of Jerome Member; section 9, Oak 

Creek Farm Road, subunit 12. X 24. (T- 187.) Unoriented. 

2. Limestone, very sandy. The rock was primarily aphanitic but is largely recrystallized. It contains calcispheres and 

other organic remains, such as the whorls of a goniatite (shown in cross section in the upper left quadrant 

of the figure) and an ostracode shell (shown in the lower left quadrant). Upper unit of Jerome Member ; section 2, 

Black River, subunit 17. X 15. (H56-5.) 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 18 

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CALCISPHERES 
PLATE 19 

FIGURE 1. Limestone containing abundant thick-walled calcispheres. The rock has a pseudoclastic texture because of extensive 

recrystallization of the original aphanitic matrix. Recrystallization has modified the shape of the calcispheres in 

varying degrees. Upper unit of Jerome Member; section 4, Salt River, subunit 18. X 30. (T56- 308U.) Unoriented. 

2. Limestone. The rock is primarily aphanitic but highly recrystallized by grain growth; it now presents a pseudoclastic 

appearance. The abundant thick-walled calcispheres are in various stages of recrystallization. At bottom of the 

figure, a completely recrystallized Amphipora skeleton is shown. Upper unit of Jerome Member; section 6, Salt 

River Draw, subunit 20. X 30. (T-107.) Unoriented. 
GEOLOGICAL SURVEY 

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t 

c 

PROFESSIONAL PAPER 464 PLATE 19 

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B 

CALCISPHERES 
PLATE 20 

FIGURE 1. Calcitic dolomite. The original aphanitic dolomitic matrix is partly dedolomitized ; many of the white crystalline areas 

are calcite. The rock contains abundant thick-walled calcispheres resembling Umbella-types, scattered small quartz 

grains, and unidentified fossil debris. Upper part of aphanitic dolomite unit of Jerome Member; section 6, Salt River 

Draw, subunit 10. X 30. (T-98). Unoriented. 

2. Aphanitic limestone containing Umbella sp., smaller calcispheres, and unidentified fossil debris. Upper unit of Jerome 

Member; section 31, Webber Creek, subunit 31. X 88. (T56-521.) Unoriented. (See also pl. 21.) 
GEOLOGI<::AL SURVEY B PROFESSIONAL PAPER 464 PLATE 20 

B 

c~ 

A~ 

t t 

A C 

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CALCISPHERES, UMBELLA 
PLATE 21 

FIGURE 1. Aphanitic limestone containing abundant Umbella sp., smaller calcispheres, and unidentified fossil debris. Upper unit 

of Jerome Member; section 31, Webber Creek, subunit 31. X 34. (T56-521.) Unoriented. 

2. Apha nitic limestone containing Umbella sp., smaller calcispheres, and unidentified fossil debris. Upper unit of Jerome 

Member; section 31, Webber Creek, subunit 31. X 34. (T56- 521.) Unoriented. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 464 PLATE 21 

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UMBELLA