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Shorter Contributions to 

Paleontology and Stratigraphy 

Edited by WILLIAM j. SANDO 

U.S. GEOLOGICAL SURVEY BULLETIN 1895 

.......... 
U.S. DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., Secretary 

U.S. GEOLOGICAL SURVEY 

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Library of Congress Cataloging in Publication Data 

Shorter contributions to paleontology and stratigraphy I 

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p. cm.-(U.S. Geological Survey bulletin ; 1895) 

Includes bibliographical references 

Supt. of Docs. no. : I 19.3: 1895 

1. Paleontology. 2. Geology, stratigraphic. I. Sando, 

William jasper. II. Series. 

QE75.B9 no. 1895 

[QE723] 

557.3 s-dc20 89-600217 

[560] CIP 
CONTENTS 

CHAPTER A 

Conodont Biostratigraphy of the Permian Road Canyon Formation, 

Glass Mountains, Texas 

Bruce R. Wardlaw and Richard E. Grant 

CHAPTER B 

The Rugose Coral Ankhelasma-lndex to Visean (Lower Carboniferous) 

Shelf Margin in the Western Interior of North America 

William j. Sando, E. Wayne Bamber, and Barry C. Richards 

CHAPTER C 

Lithostratigraphy and Conodont Biostratigraphy Across the LowerMiddle Ordovician Disconformity (Early to Middle Whiterockian) 

at Pratt Ferry, Central Alabama 

T.H. Shaw, Keith E. Roberson, and Anita G. Harris 

Chapter A 

Conodont Biostratigraphy of the Permian 

Road Canyon Formation, Glass Mountains, 

Texas 

By BRUCE R. WARDLAW and RICHARD E. GRANT 

U.S. GEOLOGICAL SURVEY BULLETIN 1895 

SHORTER CONTRIBUTIONS TO PALEONTOLOGY AND STRATIGRAPHY 

CONTENTS 

Abstract Al 

Introduction Al 

The Type Section (RC I) Al 

Supplementary Sections A3 

The Leonardian-Guadalupian Boundary A4 

Depositional Setting A4 

Conodont Biofacies AS 

Systematics A6 

Genus Hindeodus A6 

Genus Neogondolella A6 

Genus Neostreptognathodus A 7 

Genus Sweetina A 7 

Genus Sweetognathus AS 

Genus Xaniognathus AS 

Measured Sections All 

References Al6 

PLATES 

[Plates follow References] 

1. Neogondolella. 

2. Hindeodus and Neogondolella. 

3. Neostreptognathodus, Hindeodus, Sweetognathus, and Sweetina. 

4. Xaniognathus, Neostreptognathodus, and Neogondolella. 

FIGURES 

1. Map of southwestern portion of the Glass Mountains showing section locations of 

the Road Canyon Formation A2 

2. Map of paleogeographic setting of the Permian of West Texas showing location of 

the Glass and northern Del Norte Mountains A4 

3. Columnar sections of the Road Canyon Formation, Sections RC IX, RC IV, 

RC III, RC VI, RC V, and RC II Al2 

4. Columnar sections of the Road Canyon Formation, Sections RC I, RC VII, RC X, 

RC XI, RC VIII, and RC XII Al3 

TABLES 

1. HOS-NOX ratio and percent of samples that yielded conodonts from sections of the 

Road Canyon Formation AS 

2. Occurrence of conodont species in samples of the Road Canyon Formation sections 

that include underlying and overlying units A9 

Contents Ill 

Conodont Biostratigraphy of the Permian Road 

Canyon Formation, Glass Mountains, Texas 

By Bruce R. Wardlaw1 and Richard E. Grant2 

Abstract 

The Road Canyon Formation is a shallow-water carbonate that was deposited on the seaward side of the 

narrow southern shelf of the Permian basin of West Texas. 

The conodont faunal succession of Neogondolella idahoensis to Neogondolella serrata generally occurs as a sharp 

transition in the lower part of the Road Canyon Formation. 

This faunal changeover is rapid and widespread. The 

Leonardian-Guadalupian Series boundary can be recognized as the level at which N. idahoensis is replaced by N. 

serrata. 

INTRODUCTION 

The unit now known as the Road Canyon Formation 

has undergone a slow but steady rise in stratigraphic status, 

beginning as a numbered member of a formation and ending 

up as the basis for a worldwide stage of the Permian. King 

(1931) established the unit as the ''First Limestone member" 

of the Word Formation in the Glass Mountains of Texas, 

thus making it the lowermost stratigraphic unit of the 

Guadalupian Series. In keeping with a policy of naming the 

numbered units in the Glass Mountains, Cooper and Grant 

( 1964) designated the ''First Limestone member" as the 

Road Canyon Member of the Word Formation. Continued 

study of the brachiopods and the discovery of the ammonoid 

Perrinites in the Road Canyon led Cooper and Grant (1966) 

to the conclusion that the unit belonged more properly to the 

Leonardian Series and deserved formation status. However, 

the Road Canyon also contains the fusulinid Parafusulina 

rot hi, long considered to be a strong indicator of a Guadalupian age (Wilde, 1975). Because fusulinid workers did 

not agree that the Road Canyon was Leonardian, the age 

and correlations of the unit became controversial. As the 

controversy revolved about its assignment to either the 

Leonardian or Wordian Stage, one solution was to remove 

the unit from both and create a new Roadian Stage (Furnish, 

1966, 1973). This solution retained the Leonardian as a 

stage, rather than as a series, and placed the Roadian in the 

Lower Permian (Furnish, 1973). 

Manuscript approved for publication April 27, 1989. 1 U.S. Geological Survey, Reston, VA 22092. 2 Smithsonian Institution, Washington, DC 20560. 

Wilde (1975) noted that, if only the Road Canyon and 

the correlative Cutoff Shale of the Apache Mountains were 

involved, Furnish's suggestion would be a simple and 

satisfactory solution to the apparent Road Canyon age 

anomaly. Unfortunately, other units are correlated to all or 

part of the Road Canyon. and complexities abound. Moreover, recognizing the Roadian as a stage implies potential 

worldwide usage, and, with the present bipartite subdivision of the Permian, the question remains: "Does the 

Roadian Stage belong in the Lower or the Upper Permian?" 

In addition to the problems bearing directly on the Road 

Canyon Formation, the U.S. Geological Survey currently 

recognizes the Lower-Upper Permian boundary within the 

Guadalupian Series at the Word-Capitan boundary, a decision not accepted now by most Permian workers. 

The Road Canyon Formation was deposited during a 

time of maximum worldwide transgression of Permian seas; 

consequently, many units elsewhere in the world are correlated to it. In Texas, the Road Canyon contains the 

youngest of the Permian brachiopod bioherms (of Cooper 

and Grant, 1972; small moundlike organic buildups formed, 

in part, by brachiopods). A detailed biostratigraphic study 

was undertaken to resolve some of the apparent age anomalies. Because brachiopods, ammonoids, and fusulinids 

have produced differing age interpretations, an independent 

test was conducted by detailed sampling and study of 

conodonts from carefully measured sections. 

THE TYPE SECTION (RC I) 

The Road Canyon Formation has been measured by 

several stratigraphers at several places (King, 1931, p. 71; 

Cooper and Grant, 1972, p. 67), and the sequence differs 

from place to place because of irregular carbonate buildups 

in the lower part of the unit (Cooper and Grant, 1972). The 

type section is located in the hill north of Leonard Mountain 

on the east side of Gilliland Canyon, due north of the Iron 

Mountain Ranch, slightly west of the 103°15' meridian 

(Cooper and Grant, 1964; fig. 1). This section, a part of 

King's (1931) Section 17, was measured in detail by John 

Cys and published in a guidebook (Cys, 1981). We followed Cys' section, in which the units are identified by 

painted numbers, taking 7-kg samples about every 10 ft 

Conodont Biostratigraphy of the Permian Road Canyon Formation A 1 
1 03°25' 30°25'.-------------y-...,.,..,.,...,..,..,..,.,..,.........~,..,..,..,-..,..,.....,.~.,...,...,,....,..,....,..,......-.,..,...,..,.,.....,.,..,..,...,.,.~,....,..,...,.~.,..,..........,....,.,~.,.....,...~T-""""''"'="='""'=.,....,.,..,~=~~~~ 

GLASS MOUNTAINS 

EXPLANATION 

® Location of sections of Road Canyon Formation 

t:t R-anches or ranch sites 

0 5 MILES 

I I I ,· 'I I 

0 5 KILOMETERS 

Figure 1. Southwestern portion of the Glass Mountains showing section locations of the Road Canyon Formation. 

where beds were exposed and clearly in place. Samples 

were not collected from silty zones, known from experience 

to be unlikely sources of conodonts. We then measured 11 

more sections, east and west of the type section, to 

document the sequence of conodonts within the Road 

Canyon Formation. 

Thickness measurements of the Road Canyon vary 

among workers, even when the identical section is measured. Major variations stem from differing choices of unit 

boundaries. There is little doubt about the lower boundary 

at the type section because the limestone of the Road 

Canyon occurs abruptly above the thick sequence of siltstone and mudstone of the Cathedral Mountain Formation. 

However, King ( 1931), Cooper and Grant ( 1964), Cys 

( 1981), and the present writers all differ as to the upper 

boundary. 

King (1931, p. 139, Section 17) defined the "First 

Limestone member" strictly on the ledge-forming limestone, 125 ft thick, at or near the type section of the Road 

Canyon. If significant higher limestone ledges that have 

intervening siltstone are included, the total thickness is 

about 208 ft. Cooper and Grant (1964, p. 1588) picked the 

upper boundary where siltstone becomes predominant, and 

limestone is present only as thin lenses and stringers and 

report a total thickness of 228 ft. By using the same criteria 

at the same section, we measured 232ft, a small margin of 

error. Cys (1981, p. 200) picked the upper boundary at the 

A2 Shorter Contributions to Paleontology and Stratigraphy 

last stringer of limestone and reported a total thickness of 

282ft; there is an error of 10ft because the painted numbers 

show 245 followed by 260, rather than 250. Cys' measurement of 272 ft differs from ours only in the choice of the 

upper boundary; up to 232 ft, we replicated his measurements exactly. Our usage corresponds to the definition of 

the Road Canyon in its type section (Cooper and Grant, 

1964) despite Cooper and Grant's statement that it was a 

direct equivalent of King's "First Limestone member" of 

the Word Formation. 

Just above a basal crinoidal layer in the type section, 

a 50-ft-thick fossiliferous conglomeratic unit contains many 

brachiopods, chert nodules and lenses, algal sheets, and, 

especially, sponges. Rugose corals and "reef' or bankforming brachiopods of the families Richthofeniidae and 

Lyttoniidae are abundant. Some beds in the upper part of 

the conglomeratic unit have aligned ·clusters of 

Parafusulina. The conodonts in this part of the unit are 

Neogondolella idahoensis, Hindeodus excavatus, and Xaniognathus abstractus. The conglomeratic unit is capped by 

18 ft of packstone that has chert stringers and abundant 

crinoid debris; a sample taken at the 52.5-ft level contains 

the conodont species Neogondolella idahoensis and N. 

serrata. Above this level, N. serrata totally replaces N. 

idahoensis. Somewhat higher, above a bedded chert interval that Cys (1981, p. 200) reports capped by a local 

diastem, is a huge massive organic carbonate buildup of the 
kind that Cooper and Grant ( 1972) called a bioherm. This 

buildup is overlain by a 40-ft-thick yellow siliceous siltstone, from which no samples were taken. The top of the 

formation is placed at the carbonate ledge above which the 

thin-bedded siltstone typical of the Word Formation begins. 

Cys' ( 1981) selection of the uppermost of several carbonate 

lenses in the siltstone provides an ambiguous boundary for 

a distinct and mappable unit. 

SUPPLEMENTARY SECTIONS 

Section RC II is farther west on the same hill that 

contains the type section (fig. 1), where the slope faces 

westward into Gilliland Canyon and just above a small clay 

slide produced by erosion and slumping of the siltstone and 

mudstone of the Cathedral Mountain Formation. In Section 

RC II, the Road Canyon Formation is thinner than the type 

section-only 164 ft thick. As in the nearby type section, 

the formation begins with conglomeratic limestone that 

contains clasts of the Cathedral Mountain lithology and 

sponges, corals, bryozoans, and various brachiopods 

including such reef or bank-forming types as richthofeniids 

and the lyttoniid Coscinophora. Coscinophora, the 

"beaded" lyttoniid, is distinctive and characteristic of the 

Road Canyon, although it also occurs lower in the section in 

the Skinner Ranch and Cathedral Mountain Formations. 

The occurrence of this brachiopod supported the argument 

for a Leonardian age of the Road Canyon Formation 

(Cooper and Grant, 1972, 1973). In Section RC II, the top 

of the Road Canyon is placed at the base of a 43-ft interval 

of yellow-orange, thin-bedded siltstone, although thin 

lenses of pelloidal packstone occur in the siltstone higher in 

the Word Formation. 

One sample in Section RC II contains excellent 

examples of both Neogondolella idahoensis and N. serrata, 

thus revealing the point of transition between the two 

species. Samples below the 38-ft level contain only N. 

idahoensis, and those above that level contain only N. 

serrata. Beds immediately above and below that level are 

covered by soil; this cover prevents determination of the full 

extent of overlap in the ranges of the two species. 

One other section (RC VII, 113 ft thick) was measured in the hill that contains the type section, but RC VII 

is much farther east on the Hess Ranch near the easternmost 

end of the hill (fig. 1). This section is near USNM (United 

States National Museum) locality 726c where large specimens of the ammonite Perrinites, a genus thought to be 

Leonardian in age (Miller and Furnish, 1957), were found 

by Cooper and Grant (1972, pl. 15, fig. 2). This occurrence 

of Perrinites provides one of the strong arguments for a 

Leonardian age of the Road Canyon Formation. The ostreiform lyttoniid brachiopod Coscinophora occurs throughout 

the formation at this section and forms large banks in the 

lower part. 

A thin bed below the lowest Coscinophora bank 

contains the conodont Neogondolella idahoensis, and a 

Coscinophora bed above the massive bank contains N. 

serrata; the change in conodont species is inferred to occur 

within the lower massive bank, about 35 ft above the base 

of the formation. 

Farther east (fig. 1) on the Appel Ranch (now the 

Williams Bar-Crescent Ranch), the Road Canyon is only 6 

ft thick (Sections RC VIII and RC XII), but the changeover 

in species of Neogondolella is contained within this thin 

unit. Section RC VIII is a conglomeratic limestone and 

forms a ledge along the north side of the canyon just north 

of the old Word Ranch site. Section RC XII is a limestone 

ledge east of Split Tank above USNM localities 726y, 

726w, 702a', 702a, 702ent, 702un, 702low, 702inst, and 

708u (Cooper and Grant, 1972, fig. 22). Transitional in 

thickness between these thin beds and the Coscinophorarich beds of Section RC VII are Section RC X, located on 

the western side of hill 5611 near USNM locality 706, and 

Section RC XI, located on the knob that is USNM locality 

702c. 

Other sections are farther from the type section. 

Sections RC III and RC IV are in the hill, where a large 

carbonate buildup occurs, immediately west of Clay Slide 

(of King, 1931). Section RC IV is through the core of the 

carbonate mass, and Section RC III, which ends in a 

dipslope, is in the bedded flank deposits about 400ft farther 

north. Only the conodont Neogondolella serrata is present 

throughout the formation at Sections RC III and RC IV. The 

change from N. idahoensis to N. serrata probably took 

place before carbonate deposition began; that is to say, in 

the siltstones and mudstones of the underlying Cathedral 

Mountain Formation. 

Two sections were measured on the hill containing 

Clay Slide. Section RC V is on a subsidiary knob north of 

the slide itself, just above a smaller, grassier slump in the 

siltstones and mudstones of the Cathedral Mountain Formation. Both N. idahoensis and N. serrata were found in a 

sample taken 36.5 ft above the base of the formation. 

Section RC VI is immediately above Clay Slide, on the 

south flank of the hill. There N. idahoensis and N. serrata 

occur together at the 30-ft level, but a sample taken 50 ft 

above the base contained only N. serrata (along with 

species in other genera). 

A very thick section (RC IX) was measured on the 

flank of Sullivan Peak. Here the Road Canyon is thinbedded and silty and is apparently transitional to the deltaic 

facies that dominates farther to the northwest on Altuda (or 

Bird) Mountain (Davis and others, 1983). N. idahoensis 

was found at the base and about 90 ft above the base of the 

formation, and N. serrata and the brachiopod Coscinophora 

were found 246 ft above the base. The zone of transition 

between the two conodont species was not determined. 

Conodont Biostratigraphy of the Permian Road Canyon Formation A3 
THE LEONARDIAN-GUADALUPIAN 

BOUNDARY 

Species ranges of Neogondolella are the basis for 

conodont zonations of the Upper Permian and are important 

to zonation of the Lower Permian (Kozur, 1978). A 

relatively rapid changeover in species of Neogondolella 

occurs in the lower part of the Road Canyon Formation (this 

paper; Wardlaw and Grant, 1987). N. idahoensis is commonly found near the base, and N. serrata is found above 

the base. The species are separated by only a few feet or 

occur within the same sample in several sections, and the 

occurrences suggest that the changeover is rapid and overlap is small. 

A similar relatively rapid changeover from N. idahoensis to forms identified as N. serrata was documented 

(Wardlaw and Collinson, 1984, 1986; Behnken and others, 

1986) in the lower part of the Meade Peak Phosphatic Shale 

Member of the Phosphoria Formation in Wyoming and 

Idaho. Wardlaw and Collinson (1978, 1979) noted this 

change throughout the Great Basin-Rocky Mountain region. 

Behnken (1975) showed a similar sharp change in faunas 

from the Guadalupe Mountains, Texas, where N. idahoensis occurs through most of the Victoria Peak and Bone 

Spring Limestones to the uppermost part of these units, and 

N. serrata occurs at the base of the overlying Cutoff Shale 

(Behnken, 1975, figs. 5, 6). All of the units that contain the 

N. idahoensis to N. serrata succession have been correlated 

by other fossil groups (for example, brachiopods, Cooper 

and Grant, 1972, Wardlaw and Collinson, 1978; 

ammonoids, Furnish, 1973; fusulinids, Wilde and Todd, 

1968) and are considered to be time correlatives. The 

biostratigraphic succession of N. idahoensis to N. serrata 

appears to be a widespread (at least over most of a 

continent) phenomenon that marks a nearly synchronous 

event. 

We propose to define the Leonardian-Guadalupian 

boundary on the basis of the conodonts; the range of N. 

idahoensis is Leonardian, and the basal Guadalupian begins 

with the first occurrence of N. serrata. The Road Canyon 

Formation spans the boundary, and the concept of a 

Roadian Stage ceases to be useful. Consequently, we 

advocate abandonment of Roadian as a stage. This new 

boundary definition also conforms more closely to the 

original definition of the Leonard and Word Formations, 

upon which the stages are based, by including most of the 

Road Canyon (First Limestone member of the Word) in the 

Wordian (basal Guadalupian). 

Our conclusions are twofold. ( 1) The LeonardianGuadalupian boundary can be defined as the level at which 

N. idahoensis is replaced by N. serrata. (2) The concept of 

a Roadian Stage should be abandoned. 

DEPOSITIONAL SETTING 

King (1942, fig. 18) (fig. 2) presented the generally 

accepted Permian regional geography of West Texas. The 

A4 Shorter Contributions to Paleontology and Stratigraphy 

30° 

106° 

' ""''· "·· 

NORTHERN·· ' 

DEL NORTE 

MOUNTAINS 

GLASS MOUNTAINS 

0 50 MILES 

f---r---1 

0 50 KILOMETERS 

Figure 2. Paleogeographic setting of the Permian of West 

Texas (from King, 1942) showing location of the Glass and 

northern Del Norte Mountains. 

Permian sediments of the Glass Mountains were deposited 

on the narrow southern shelf between the Marathon folded 

belt, which formed a land area to the south, and the Hovey 

channel and Delaware basin, which formed a relatively 

deep marine channel and basin to the north. King (1931), in 

his classic study of the Glass Mountains, noted that the 

distribution of sediments in Leonard and Word time showed 

that sandstone, conglomerate, and radiolarite were thickest 

near the uplifted area to the south and thinned to the north 

and northeast where they were replaced laterally by limestone (King, 1931, p. 89). This configuration is one of inner 

shelf clastics and outer shelf carbonates deposited on a very 

narrow shelf. 

Cys ( 1981) differed with this interpretation radically 

by postulating a shelf boundary perpendicular to that of 

King's (Cys, 1981, fig. 11; Cys andMazzullo, 1978, fig. 5) 

and by interpreting the Leonard sediments as being largely 

slope and basin deposits; radiolarites indicating basinal 

deposition and thin limestones to the northeast indicating 

shallow shelf deposition. 

Cooper and Grant (1972) agreed with King's general 

shelf deposition for the Leonard and Word sediments. 

Further, they noted that, to the southwest in the Del Norte 

Mountains (fig. 2) in late Cathedral Mountain time, local 

uplift shed coarse conglomerates composed of well-rounded 

pebbles. Abundant transported ammonoids, fragmentary 

brachiopods, and numerous plant ste~ fragments indicated 

a shore zone (Cooper and Grant, 1972, p. 99). Rohr and 

others (1982) and Davis and others (1983) interpreted the 

conglomerates and related siltstones in the Del Norte 

Mountains to be nonmarine fluvial and marine deltaic 

deposits. Many delicate, well-preserved leaves are present 

in the siltstones (Mamay and others, 1984; Rohr and others, 

1987), and these sediments are equivalent to the upper part 
of the Cathedral Mountain and Road Canyon Formations 

(Mamay and others, 1984; Wardlaw, unpub. conodont 

data). 

The Road Canyon Formation is, perhaps, the most 

poorly known unit in the Glass Mountains. Although Cys 

( 1981) did not interpret the depositional environment for the 

Road Canyon Formation in his Leonardian study, he 

showed it unconformably overlying "basinal" deposits of 

the Cathedral Mountain Formation. 

The Road Canyon Formation represents widespread 

carbonate deposition during transgression, apparently 

related to a worldwide sea-level rise (Wardlaw, 1980). The 

Road Canyon interfingers with the deltaic and fluvial 

deposits of the Del Norte Mountains and probably represents relatively shallow-water deposition. In many places, 

the Road Canyon is conglomeratic both at its base and 

throughout much of its thickness. Clasts include irregular 

limestone and siltstone cobbles that are either penecontemporaneous or are derived from the underlying Cathedral 

Mountain Formation and flat siltstone cobbles that are 

derived from the underlying Cathedral Mountain Formation. In no instance do the limestone clasts and matrix yield 

different conodont faunas. The clasts indicate active 

reworking of underlying and penecontemporaneously lithified sediments and very little transport; we interpret this to 

be indicative of shallow-water deposition. 

Carbonate buildups within the Permian of the Glass 

Mountains have been interpreted as being either in place or 

redeposited (see Cys and Mazzullo, 1978, and Flores, 

McMillan, and Watters, 1978). Sedimentologists with one 

prejudice or another seem to select buildups that tend to 

support their own interpretations. Each buildup should be 

analyzed separately; many are in place and many are not. 

The Coscinophora bank at RC IV, the flank deposits at RC 

III, and the Coscinophora banks at RC VII are in-place 

buildups. The more diversified buildups at the base of RC I 

and RC IX may be redeposited. In spite of a diversity of 

opinions, we feel that the depositional features indicate 

shallow-water deposition. 

CONODONT BIOFACIES 

Wardlaw and Collinson (1984) showed conodont 

biofacies distributions for the Permian Phosphoria Formation and related rocks in the Rocky Mountains. The Road 

Canyon Formation and the lower part of the Phosphoria 

Formation were deposited during the same time interval 

(see Behnken and others, 1986), and both formations 

contain the same conodont species. Generally, Wardlaw 

and Collinson found that Hindeodus and Sweetina characterize nearshore environments and Neogondolella and Xaniognathus characterize offshore environments. Following 

the distribution model of Wardlaw and Collinson (1984), 

the Road Canyon Formation would have been deposited in 

intermediate to offshore environments because there is a 

mixing of offshore and nearshore elements. Neogondolella 

and the complete seximembrate apparatus of Xaniognathus 

are better represented than the seximembrate apparatuses of 

Hindeodus and Sweetina, probably due to transportation of 

the latter. The distribution of conodonts supports offshore 

deposition. 

Neostreptognathodus, which characterizes intermediate environments in the Phosphoria Formation, is very rare 

in the Road Canyon Formation. Sweetognathus, which is 

very rare in the Phosphoria, is also rare in the Road Canyon 

but is more common than Neostreptognathodus. Perhaps 

these differences can be explained by the narrow depositional shelf that must have existed during the deposition of 

the Road Canyon as compared to the broad depositional 

shelf that existed during the deposition of the Phosphoria. 

The narrow shelf would have compressed the biofacies, 

made differentiation of the biofacies less clear, increased 

overlap of the biofacies, and perhaps been unfavorable for 

such intermediate forms as Neostreptognathodus. Offshore 

shelf deposition for the Road Canyon Formation fits well 

with the original depositional interpretations of King 

(1931). 

The ratios of number of samples containing Hindeodus or Sweetina or both to number of samples containing 

Neogondolella or Xaniognathus or both in each section 

(table 1) show that Neogondolella and Xaniognathus are 

generally more common than Hindeodus and Sweetina. 

Section RC IV is the exception, because Hindeodus and 

Sweetina are more common than Neogondolella and Xaniognathus, possibly indicating very shallow-water deposition. Also shown in table 1 is the percentage of samples that 

yielded conodonts in each section. Samples were generally 

of equal size and averaged 7 kg. Apparently, two factors 

severely limit the recoverability of conodonts. Sections RC 

Table 1. HOS-NOX ratio and percent of samples that 

yielded conodonts from sections of the Road Canyon 

Formation 

[HOS, number of samples containing Hindeodus or Sweetina or both; 

NOX, number of samples containing Neogondolella or Xaniognathus or 

both] 

Yield, 

Section in percent HOS:NOX 

RC I 88 0.64 

RC II 90 .50 

RC III 91 .86 

RCIV 43 1.50 

RCV 50 .50 

RC VI 60 .67 

RC VII 67 .67 

RC VIII 80 1.00 

RCIX 50 .33 

RCX 100 1.00 

RC XI 100 1.00 

RC XII 100 1.00 

Conodont Biostratigraphy of the Permian Road Canyon Formation AS 
V. RC VI, and RC IX (figs. 1, 3) are dominated by platy 

and thin-bedded, silty lime-mudstone and siltstones and 

have poor conodont recovery, reflecting a greater influx of 

silt during deposition. Sections RC IV and RC VII (figs. 3, 

4) are primarily Coscinophora-dominated carbonate buildups that have poor conodont recovery, probably reflecting 

very shallow water deposition. 

SYSTEMATICS 

Upper Paleozoic conodont species have been shown 

by Merrill and Powell ( 1980) to be variably represented by 

apparatuses. Although most individuals apparently start 

with a full complement of elements (generally six different 

kinds), some lose elements during ontogeny. Ontogenetic 

loss appears to vary among species and between environments but seems most variable between genera. For all 

practical purposes, genera can be characterized as ( 1) those 

that retain a full complement of elements through life, (2) 

those that lose a few elements (rare), (3) those that 

commonly lose most of the elements but show rare cases of 

total retention, and ( 4) those that occur only as a single 

element and do not commonly have a full complement of 

elements. In our material, Hindeodus, Sweetina, and Xaniognathus appear to be represented by seximembrate apparatuses (type 1). Neostreptognathodus and Sweetognathus 

appear to be represented by rarely occurring seximembrate 

apparatuses; both are generally represented by just the Pa 

element (type 3). Neogondolella appears to be represented 

by a single element platfonn (Pa) apparatus that probably 

occurred as a pair (type 4). The occurrence of conodont 

species in our material is shown in table 2. 

Genus Hindeodus Rexroad and Furnish, 1964 

Type Species.-Hindeodus cristulus 

(Youngquist and Miller, 1949), 

Rexroad and Furnish, 1964, p. 671-672. 

Hindeodus excavatus (Behnken) 

Plate 2, figures 1-15: plate 3, figures 3-11 

Ellisonia excavata Behnken, 1975. p. 302, pl. 1, figs. 

9-14. 

Anchignathodus minutus (Ellison) Behnken, 1975, p. 297, 

pl. 1, figs. 16-18. 

Hindeodus excavatus (Behnken), Sweet, 1977a. p. 215, pl. 

1, figs. 7-11; Wardlaw and Collinson, 1984, p. 

268-269, pl. 5, figs. 1, 2, 4-9; 1986, p. 133, fig. 

17:13-20. 

Diagnosis.-A species of Hindeodus characterized 

by a Pa element with a large cusp; denticles increase in 

width anteriorly, except for the anteriormost, and generally 

decrease in height anteriorly, except for the posteriormost 

three, which may be of subequal height; cusp is much 

higher than denticles; and an Sa element with short lateral 

processes that are slightly upturned laterally and that bear 

for at least part of their length denticles of alternating 

A6 Shorter Contributions to Paleontology and Stratigraphy 

(smaller versus larger) sizes (see Behnken, 1975, p. 299, 

pl. 1, fig. 12). The entire apparatus is illustrated in Sweet 

(1977a) and Wardlaw and Collinson (1984, 1986). 

Discussion. -H. excavatus is commonly represented 

in our collections by the Pa element and a few broken 

ramiform elements. Of these, Sc elements are most common, followed by M, Sb, and Pb elements. No Sa element 

was recovered. We interpret the incomplete and broken 

condition of the elements of Hindeodus to indicate that the 

skeletal remains of this species were probably deposited in 

high-energy environments and, in part, were probably 

transported short distances. H. excavatus appears to be the 

only conodont common to the Coscinophora banks that we 

also interpret as being deposited in high-energy and very 

shallow water environments. 

Genus Neogondolella Bender and Stoppel, 

1965 

Type Species.-Neogondolella mombergensis 

(Tatge), 1956, pl. 6, figs. 1, 2. 

Neogondolella idahoensis 

(Youngquist, Hawley, and Miller) 

Plate 1, figures 8, 9, 14-16, 19-22; plate 2, figures 20-22, 26-28; 

plate 4, figures 24, 25 

Gondolella idahoensis Youngquist, Hawley, and Miller, 

1951, p. 361, pl. 54, figs. 1-3, 14, 15; Clark and 

Ethington, 1962, p. 108, pl. 2, figs. 15, 16; Clark and 

Mosher, 1966, p. 388, pl. 471 figs. 9-12; Clark and 

Behnken, 1971, p. 431, fig. 9; Kozur, 1978, pl. 5, 

figs. 2. 15, 16. 

Neogondolella idahoensis (Youngquist, Hawley, and 

Miller), Behnken, 197 5, p. 306-307, pl. 1 , figs. 

28-30; Wang, 1978, p. 220-221, pl. 2, figs. 23-26; 

Igo, 1981, p. 38, pl. 1, figs. 11-13, 15, 16; Wardlaw 

and Collinson, 1984, p. 269, pl. 1, figs. 10, 11, 1986, 

p. 133, fig. 17:11, 12; Behnken, Wardlaw, and Stout, 

1986, p. 179-181, fig. 4:12-16, 18. 

Gondolella phosphoriensis Youngquist, Hawley, and 

Miller (part), 1951, p. 362, pl. 54, figs. 27, 28; Clark 

and Ethington, 1962, p. 108, pl. 2, figs. 17-18. 

Diagnosis.-A species of Neogondolella characterized by a platform of moderate width that gradually narrows 

in the anterior two-thirds of its length and has a blunt, 

squared posterior platform margin; denticles that generally 

increase in size anteriorly, except for the anterior one or 

two; and well-developed furrows. 

Discussion.-Our examples of N. idahoensis appear 

to be very similar to those previously described from the 

Phosphoria Formation in Idaho (Youngquist, Hawley, and 

Miller, 1951) and the Bone Spring Limestone in West 

Texas (Clark and Ethington, 1962; Behnken, 1975). This 

species seems reasonably consistent in morphology 

throughout its worldwide distribution. 
Neogondolella serrata (Clark and Ethington) 

Plate 1. figures 1-7. 10-13. 17, 18; plate 2. figures 16-19. 23-25 

Gondolella serrata Clark and Ethington, 1962, p. 108-109, 

pl. 1. figs. 10, 11, 15, 19, pl. 2, figs. 1, 5, 8, 9, 11-14; 

Clark and Mosher, 1966, p. 389, pl. 47, figs. 13-15; 

Clark and Behnken, 1971, p. 431, pl. 1, fig. 10: 

Kozur, 1978, pl. 5, fig. 22. 

Neogondolella serrata (Clark and Ethington), Wang, 1978, 

p. 222, pl. 2, figs. 6-8, 14, 15, 20-22; Clark and 

Behnken, 1979, p. 268-271, pl. 1, fig. 12; Wardlaw 

and Collinson, 1984, p. 270, pl. 2, figs. 13-15, 1986, 

p. 133-134, fig. 17:7, 8; Behnken, Wardlaw, and 

Stout, 1986, p. 183, fig. 5:20, 21, 23-31. 

Neogondolella serrata serrata (Clark and Ethington), 

Behnken, 1975, p. 308, pl. 2, figs. 21-24, 37. 

Diagnosis.-A species of Neogondolella characterized by a platform of moderate width, which is generally 

short and arched, narrows anterior to the middle, and has a 

round to blunt posterior platform margin; lateral platform 

margin variably serrated, commonly with at least three or 

more paired serrations on the anterior, tapering part of 

platform, rarely serrated for almost entire margin; a moderate cusp of circular cross section: denticles generally 

increasing in size anteriorly except commonly one or two 

smaller denticles along middle of carina and one or two 

denticles at anterior end; and moderately developed furrows. 

Discussion.-N. serrata appears to show the earliest 

regional morphologic variation that begins provincialism in 

Permian neogondolellids. Specimens from Idaho can be 

distinguished from those of West Texas, although in both 

regions N. serrata appears to replace N. idahoensis with 

remarkable synchroneity. The younger species of Neogondolella in Idaho are completely different from those of West 

Texas, and soN. serrata appears to be the youngest species 

to show worldwide distribution; however, it presages the 

later trend of provincialism by developing distinct geographic morphotypes. 

Genus Neostreptognathodus Clark, 1972 

Type Species.-Neostreptognathodus sulcoplicatus 

(Youngquist, Hawley, and Miller, 1951), 

Clark, 1972, p. 155. 

Neostreptognathodus clinei Behnken 

Plate 3, figure 2; plate 4, figure 23 

Neostreptognathodus c/inei Behnken, 1975, p. 309-310, 

pl. 2, figs. 15, 16: Sweet. 1977b, p. 237, pl. 1, fig. 4; 

Wardlaw and Collinson, 1984, p. 270, pl. 5, fig. 13; 

Behnken, Wardlaw, and Stout, 1986, p. 183, fig. 4:6, 

7. 

Diagnosis.-A species of Neostreptognathodus characterized by a platform element (Pa) with two carinae that 

are smooth or only faintly ornamented posteriorly by poorly 

developed nodes; carinae separated by a distinct groove; 

blade joins platform at center. 

Discussion. -N. clinei is a rare long-ranging form 

that is found throughout North America in upper Leonardian and lower Guadalupian strata. A Pb element recovered 

from the lower part of the Word Formation, Section RC I, 

belongs to the apparatus of Neostreptognathodus (see 

Wardlaw and Collinson, 1986). It is tentatively assigned to 

N. c/inei and illustrated (pl. 4, fig. 23) to compare with Pb 

elements of Xaniognathus. 

Neostreptognathodus newelli Wardlaw and 

Collinson 

Plate 3, figure 1 

Neostreptognathodus newelli Wardlaw and Collinson, 

1984, p. 270, pl. 5, figs. 10-12, 14-17; 1986, p. 135, 

fig. 18:4. 

Neostreptognathodus sp. C. Baird, 1975, p. 41--42, pl. 1, 

figs. 11, 12: Wardlaw and Collinson, 1978, p. 1177; 

1979, p. 152. 

Diagnosis.-A species of Neostreptognathodus characterized by a platform element (Pa) with two carinae 

ornamented by 12 to 17 pairs of slightly oblique, low 

transverse ridges that are separated by a narrow but distinct 

median groove; posteriormost one to three ridges merge, 

terminating the median groove; blade joins platform slightly 

off center (in contrast to N. sulcoplicatus and N. clinei, 

which are centered) and has a poorly developed groove, 

which separates the blade from the closest carina. 

Discussion.-N. newelli is rare in the Road Canyon 

Formation and occurs only in one sample. It is common 

throughout most of the Great Basin and northern Rocky 

Mountains and is diagnostic of the Peniculauris bassiNeostreptognathodus newelli Zone (formerly N. sp. C) of 

Wardlaw and Collinson (1978) that they correlated with the 

upper part of the Road Canyon. This fortuitous recovery 

strengthens that correlation. The Peniculauris bassiNeostreptognathodus newelli Zone is the near-shore time 

equivalent of the Neogondolella sen·ata Zone, found in the 

Phosphoria Formation in Idaho and in the Cutoff Shale and 

Road Canyon Formation in West Texas. 

Genus Sweetina Wardlaw and Collinson, 1986 

Type Species.-Sweetina triticum Wardlaw 

and Collinson, 1986, p. 135-138. 

Sweetina festiva (Bender and Stoppel) 

Plate 3, figures 18-25 

Lonchodinafestiva Bender and Stoppel, 1965, p. 345-346, 

pl. 15, figs. 9, 10. 

Stepanovites festiva (Bender and Stoppel), Kozur, 1975, p. 

23; Kozur, 1978, pl. 5, fig. 29; Kozur and MovschoConodont Biostratigraphy of the Permian Road Canyon Formation A7 
vitsch, 1979, p. 119, pl. 4, figs. 1, 2; Wardlaw and 

Collinson, 1984, p. 271, pl. 3, figs. 4-11. 

Sweetina festiva (Bender and Stoppel), Wardlaw and Collinson, 1986, p. 138. 

Diagnosis. -A species of Sweetina characterized by 

a pastinate Pa element with a poorly developed lateral 

process and a dygyrate M element with a very large cusp; 

one to three anterolateral denticles, generally no posterolateral denticles; and a greatly flared triangular basal cavity 

that is directed posterolaterally. 

Discussion.-The entire apparatus of Sweetina triticum is illustrated in Wardlaw and Collinson (1986, fig. 20). 

S. festiva appears to have an apparatus that is very similar to 

that of S. triticum except for the Pa element. The Pa element 

of S. festiva has a longer lateral process, a less prominent 

cusp, and a less well developed basal cavity than the Pa 

element of S. triticum. S. festiva is commonly represented 

in our material by broken ramiform and platform elements. 

Sc elements are the most common followed by fairly 

common M elements, and then by Pa, Sb, and Sa elements. 

No Pb elements were recovered. The occurrence of S. 

festiva is thought to be similar to that of Hindeodus 

excavatus. 

Genus Sweetognathus Clark, 1972 

Type Species.-Sweetognathus whitei 

(Rhoades, 1963), Clark, 1972, p. 155. 

Sweetognathus iranicus Kozur, Mostler, and 

Rahimi-Yazd 

Plate 3, figures 12-17 

Sweetognathus iranicus Kozur, Mostler, and Rahimi-Yazd, 

1975, p. 9-10, pl. 4, figs. 1-10, pl. 5, figs. 2-4; 

Kozur, 1978, pl. 6, figs. 4, 7-10, 13, 15, 18. 

Diagnosis.-A species of Sweetognathus characterized by a Pa element with rounded denticles or nodes that 

have pustulose microomament forming a row of small 

nodes connected by a thin pustulose longitudinal ridge that 

is laterally, not centrally, placed and a variably developed 

secondary row of nodes that generally through growth 

become larger than, and merge with, the primary row to 

form transverse ridges. 

Discussion.- S. iranicus is rare in the Road Canyon 

Formation. A partial apparatus has been illustrated for 

Sweeto gnathus (Ritter, 1986). Our sparse material appears 

to be represented only by Pa elements. S. iranicus was 

originally described from the Abadeh section of central Iran 

(Kozur, Mostler, and Rahimi-Yazd, 1975). S. iranicus 

A8 Shorter Contributions to Paleontology and Stratigraphy 

appears to range throughout the Road Canyon Formation 

and into the lower part of the Word Formation in West 

Texas. 

Genus Xaniognathus Sweet, 1970 

Type Species.-Xaniognathus curvatus Sweet, 

1970, p. 262. 

Xaniognathus abstractus (Clark and Ethington) 

Plate 4, figures 1-22 

Subbryantodus abstractus Clark and Ethington, 1962, p. 

112-113, pl. 1, figs. 16, 20, 21, pl. 2, fig. 2. 

Lonchodina mulleri Tatge, Clark and Ethington, 1962, p. 

110-111, pl. 1, fig. 4. 

Apatognathus tribulosus Clark and Ethington, 1962, p. 

107, pl. 1, figs. 3, 7, 13, 17. 

Xaniognathus abstractus (Clark and Ethington), Behnken, 

1975, p. 313, pl. 1, fig. 15; Wardlaw and Collinson, 

1984, p. 271, pl. 2, figs. 1-12; Wardlaw and Collinson, 1986, p. 135, fig. 18:17-23; Behnken, Wardlaw, 

and Stout, 1986, p. 185, figs. 5:4-7, 6:7-20. 

Xaniognathus sp. Malkowski and Szaniawski, 1976, p. 83, 

pl. 1' fig. 2. 

Xaniognathus tortilis (Tatge), Behnken, 1975, p. 313, pl. 

2, fig. 13. 

Sweetocristatus arcticus Szaniawski, 1979, p. 254, pl. 9, 

figs. 1-7. 

Ozarkodina tortilis Tatge, Clark and Behnken, 1971, p. 

433, pl. 2, fig. 8. 

{A complete element synonymy is given in Behnken, 

Wardlaw, and Stout, 1986} 

Diagnosis.-A species of Xaniognathus characterized by the delicate, greatly recurved Sb (Apatognathus 

tribulosus) element with large cusp and low denticles on 

one process and a large variable Pb element with a twisted 

posterior process commonly bearing five to eight denticles, 

rare specimens have more denticles; and an anterior process 

commonly bearing 7 to 11 or more denticles, with midlateral rib for most of its length; anterior process variable, 

robust to relatively thin and delicate. The entire apparatus is 

illustrated in Wardlaw and Collinson (1984, pl. 2; 1986, 

fig. 18) and Behnken, Wardlaw, and Stout (1986, fig. 6). 

Discussion. -X. abstractus is abundant and well 

preserved in many of our samples. Sb, M, and Pa elements 

are the most commonly recognized, although many undetermined fragments probably represent Sc elements. Sa and 

Pb elements are slightly less common. The complete 

representation and excellent preservation of Xaniognathus 

indicate that it is a truly indigenous faunal element. 
Table 2. Occurrence of conodont species in samples of the Road Canyon Formation sections that include underlying 

and overlying units 

[1, Neogondolella idalwensis: 2, Neogondolella serrata: 3, Hindeodus excamtus: 4. Sweetina festiva; 5, Sweetognathus iranicus: 6, Xaniognathus 

abstractus; 7. Neostreptognathodus clinei: 8, Neostreptognatlwdus newelli: 9, Neostreptognathodus sulcoplicatus] 

Sample Footage Conodonts 

2 3 4 5 6 7 8 9 

RC I 

W81161 0.5 X X X 

W81162 7.5 X X X 

W81163 26.0 X X 

W81164 40.0 

W81165 52.5 X X X X X 

W81166 68.0 X X 

W81167 77.5 

W81168 86.0 X X 

W81169 110.0 X X X 

W81170 155.0 X 

W81171 170.0 X X 

W81172 192.0 X X 

W81173 212.0 X 

W81174 229.0 X X X 

W81175 250.0 X X X 

W81176 272.0 X X X X X X 

RC II 

W81179 -61.0 X X X X 

W81189 .0 X 

W81188 12.0 

W81187 38.0 X X X 

W81186 61.0 X X 

W81185 109.0 X X 

W81184 129.0 X 

W81183 144.0 X 

W81182 164.0 X X 

W81181 211.0 X X X 

W81180 234.0 X X 

RC III 

W81191 1.0 X X X 

W8239 2.5 X 

W8240 4.0 X X 

W81192 17.0 X 

W81193 28.0 

W81194 32.0 X X X 

W81195 39.0 X 

W81196 45.0 X X X X 

W81197 60.0 X X X 

W81198 74.0 X 

W81199 86.0 X 

RC IV 

W81200 2.5 X X X 

W8241 3.0 X X X 

W81201 17.0 

W81202 39.0 

W81203 67.0 X 

W81204 80.0 

W81205 98.0 

RC V 

W81209 4.5 X X 

W81208 36.5 X X 

W81207 49.0 

W81206 77.0 

RC VI 

W81214 5.0 

W81213 30.0 X X X 

Conodont Biostratigraphy of the Permian Road Canyon Formation A9 
Table 2. Occurrence of conodont species in samples of the Road Canyon Formation sections that include underlying 

and overlying units-Continued 

[1, Neogondolella idahoensis; 2, Neogondolella sen·ata; 3, Hindeodus excavatus; 4, Sweetina festiva; 5, Sweetognathus iranicus; 6, Xaniognathus 

abstractus; 7, Neostreptognathodus clinei; 8, Neostreptognathodus newelli; 9, Neostreptognathodus sulcoplicatus] 

Sample Footage Conodonts 

2 3 4 5 6 7 8 9 

W81212 50.5 X X 

W81211 72.0 

W81210 87.0 X X 

RC VII 

W81217 1.5 X X X X 

W81218 13.5 X X 

W81219 18.0 

W827 19.0 

W828 27.0 X 

W81220 35.0 

W829 35.0 X 

W81221 49.0 

W81222 70.0 X 

W81223 89.0 X 

W81224 112.0 X 

W81215 130.0 X X X X 

RC VIII 

W81226 1.5 X X 

W81227 26.0 X X X X 

W8210 27.5 X X 

W8211 28.5 

W8212 29.5 X X X 

W81228 30.5 X X X X X 

W81229 39.0 

W81230 59.0 

RC IX 

W81244 0.0 X X 

W81243 5.0 X X X 

W81241 74.0 X 

W8242 95.0 

W8244 114.0 

W8243 139.5 

W81242 144.0 

W8245 160.0 

W8246 195.0 

W81236 246.0 X X X 

W81237 251.5 X X 

W81238 272.5 X 

W81239 281.5 X X X 

W81240 291.0 X X 

RC X 

W877 1.0 X X X X 

W878 29.0 X X 

W879 52.0 X X X 

RC XI 

W81225 0.5 X X X X X X X 

W876 3.5 X X X X X 

702C 5.5 X X X 

RC XII 

W8471 0.5 X X X X X xl 

W8472 5.5 X X X X 

1

Poor specimen of Neostreptognatlzodus sulcoplicatus. 

A 1 0 Shorter Contributions to Paleontology and Stratigraphy 
MEASURED SECTIONS 

Section RC I (fig. 4) 

Type section of the Road Canyon Formation. Hill north of 

Leonard Mountain, east side of Gilliland Canyon, west of 103°15' 

meridian. Compare with sections by Cooper and Grant (1964) and 

Cys ( 1981) at the same locality. 

CumuThickness lative 

Word Formation (ft) (ft) 

11. Siltstone, yellow, siliceous with thin- to 

medium-bedded limestone stringers: conodont sample at 272 ft . . . . . . . . . . . . . . . . . . . . 20 272 

10. Siltstone, yellow, siliceous. capped by 3-ft 

bed of skeletal packstone with abundant 

brachiopod spines. brachiopods, echinoids, 

ammonoids. corals. bryozoans, sponges, 

aligned fusulinids; conodont sample at 250 

ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 252 

Road Canyon Formation 

9. Limestone, gray, rubbly weathering. mediumto thick-bedded, silty peloid packstone with 

some chert, most peloids are algal coated; 

aligned fusulinids. corals, snails, brachiopods (Collenzataria at 230 ft); conodont 

samples at 229. 212, 192ft . . . . . . . . . . . . . . 42 232 

8. Siltstone, yellow, siliceous, thin-bedded, thin 

lenses of medium-brownish-gray, silty 

wackestone with Parafusulina; conodont 

sample at 170 ft . . . . . . . . . . . . . . . . . . . . . . . . . 23 190 

7. Limestone ledge, medium-brownish-gray 

skeletal packstone with fossil bed at 160 ft 

containing brachiopods (Collenzataria, Derbyia, Neophricadothyris, Neospirifer, 

Megousia), sponges, corals, echinoid 

debris, sponge spicules; conodont sample at 

155 ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 167 

6. Siltstone, yellow, siliceous, shaly-bedded 

with thin beds of peloid packstone........ 27 154 

5. Siltstone with thin beds of peloid packstone 

changing upward to packstone with thin 

stringers of siltstone: fusulinids, crinoid 

columnals; conodont sample at 110 ft..... 40 127 

4. Limestone, massive organic carbonate 

buildup, medium-brownish-gray wackestone; sponges, corals, bryozoans, brachiopods (Composita, Coscinophora, Derbyia, 

Meekella, Peniculauris); conodont sample 

at 86 ft; barren sample at 77.5 ft . . . . . . . . . 12 87 

3. Chert, bedded, compressed by overlying carbonate, medium-brownish-gray. weathers 

light brown, spiculitic, top is Cys' "local 

diastem". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 75 

2. Limestone, brownish-medium-gray packstone 

with rusty chert stringers of skeletal hash, 

medium-bedded; conodont samples at 68, 

52.5 ft.................................. 18 68 

1. Conglomeratic limestone, medium-brownishgray, weathers orange to brown, packstone 

to wackestone, chert as boulders and stringers, clasts from pebble to boulder size, 

limestone and chert; fossils mostly sponges 

and corals, also crinoid columnals, brachiopods ( Compressoproductus, Coscinophora, Derbyia, Dyoros, Meekel/a, Neophricadothyris, Neospirifer, Peniculauris, 

richthofeniids); base is 0.5 ft of mediumorangish-gray crinoidal packstone; conodont 

samples at 26, 7. 5, 0. 5 ft; barren sample at 

40ft .................................. . 

Section RC II (fig. 3) 

50 50 

Measurements made on the southwest-facing side of Hill 

5779 (the same hill that contains the type section on its south side), 

above an eroded scar of Cathedral Mountain siltstone and mudstone that forms a small clay slide. 

CumuThickness lative 

Word Formation (ft) (ft) 

9. Siltstone, yellow-orange, thin-bedded, very 

localized lenses and beds of peloid packstone up to 4 ft thick appear to be channel 

deposits; corals and other fossils; conodont 

sample at 234, 211 ft.................... 37 244 

8. Siltstone, yellow-orange, thin-bedded, minor 

amounts of limestone, partly covered . . . . . 43 207 

Road Canyon Formation 

7. Limestone, light-brownish-gray, coarsegrained peloid packstone with abundant corals, crinoid debris, few brachiopods 

(Meekella, Orthotichia), a massive carbonate buildup that becomes bedded and silty 

toward top; conodont samples at 164, 144, 

129, 109ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 164 

6. Covered, probably thin-bedded siltstone..... 40 104 

5. Limestone, medium-brownish-gray peloid 

skeletal packstone with rusty brown silicified "skins" on bedding planes and joints; 

conodont sample at 61 ft . . . . . . . . . . . . . . . . . 17 64 

4. Covered, probably shaly siltstone........... 8 47 

3. Limestone, medium-olive-gray, fine-grained 

skeletal packstone with corals, bivalves, 

crinoid columnals, richthofeniid brachiopods, chert nodules and stringers; conodont 

sample at 38 ft . . . . . . . . . . . . . . . . . . . . . . . . . . 2 39 

2. Covered, gentle slope probably hides thinbedded shaly siltstone.................... 21 37 

1. Conglomeratic limestone, olive-gray skeletal 

packstone, thick-bedded with yellow siltstone pebbles and platelets of Cathedral 

Mountain Formation; corals, sponges, fusulinids, bryozoans, brachiopods (Coscinophora, richthofeniids); conodont sample at 0 

ft: barren sample at 12 ft................. 16 16 

Cathedral Mountain Formation 

0. Mudstone and siltstone, easily eroded, partly 

covered, few beds of silty skeletal wackestone with brachiopods; conodont sample 61 

ft below base of Road Canyon Formation. 

Section RC III (fig. 3) 

Hill west of hill containing Clay Slide; bedded flank 

deposits about 400 ft north of core of massive carbonate buildup. 

CumuThickness lative 

Road Canyon Formation (ft) (ft) 

8. Limestone, medium-gray, sandy, skeletal lime 

Conodont Biostratigraphy of the Permian Road Canyon Formation A 11 
FEET RCIX 

250 

200 

150 

100 

50 

0 

~ 

~ .... 

Q) 

(/) 

~ 

~ 

0 

"C 

c: 

0 

0) 

0 

Q) 

<: 

METERS 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Figure 3. Columnar sections of the Road Canyon Formation, Sections RC IX, RC IV, RC Ill, RC VI, RC V, and RC II. 

Lithic symbols as in figure 4. 

A 12 Shorter Contributions to Paleontology and Stratigraphy 
RCI 

FEET 

EXPLANATION 

~Limestone 

§Dolostone 

~~-:=I Siltstone and mudstone 

I: -1 Chert 

250 ·1~=1 Conglomeratic 

D Covered interval 

= Limestone clasts 

~ Siltstone clasts 

Limy 

Silty 

Cherty 

200 ~ 

~ .... 

Q) 

Cl) 

~ 

Q) 

Q 

"0 

c: 

0 

Ol 

0 

Q) 

c <: 0 

150 ·.;:; 

co 

E 

0 

u.. 

c 

0 

> 

c 

co 

u 

"0 

co 

0 

0::: 

100 

RC XII 

I ~ .~ 

Cl) 

50 II ~ 

Q) 

Q 

"0 

c: 

0 

Ol 

0 

Q) 

<: 

0 1 

Figure 4. Columnar sections of the Road Canyon Formation, Sections RC I, RC VII, RC X, RC XI, RC VIII, and RC XII. 

RC I is the type section of the Road Canyon Formation. Datum is the sharp changeover from Neogondolella idahoensis 

to N. serrata. 

METERS 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Conodont Biostratigraphy of the Permian Road Canyon Formation A 13 
mudstone to wackestone with chert nodules 

and beds; abundant corals, bryozoans, crinoid debris, few sponges, fusulinids in 

swirls, brachiopods (Derbyia, Meekella); 

conodont samples at 86, 74, 60ft ....... . 

7. Limestone, medium-gray lime mudstone with 

chert lenses, medium-bedded, partly covered ................................... . 

6. Limestone, medium-gray lime mudstone, 

medium-bedded with brachiopods (Neospirifer, abundant Megousia); conodont sample 

at 45 ft ................................ . 

5. Limestone, orange-brown-gray, silty skeletal 

wackestone to packstone, bryozoans, crinoid columnals, brachiopods (Hustedia), 

chert nodules (not beds); represents a thin 

finger of the carbonate buildup into flank 

deposits; conodont sample at 39 ft ....... . 

4. Limestone, medium-gray sandy lime mudstone, fine-grained; corals, clams, bryozoans, brachiopods (Neospirifer, abundant 

Megousia at 37 ft); conodont sample at 32 

ft; barren sample at 28 ft ................ . 

3. Limestone, orange-gray skeletal wackestone, 

thick-bedded with rusty colored sponges, 

carbonate pebbles and cobbles, corals, 

sponges, brachiopods ( Coscinophora clusters); represents a finger of the carbonate 

buildup into flank deposits; conodont sample at 17 ft. ............................ . 

2. Covered, probably sandy, silty carbonate ... . 

1. Limestone, medium-gray lime mudstone with 

chert lenses, fine sand; scattered corals, 

brachiopods; conodont samples at 4, 2.5, 1 

ft ..................................... . 

Section RC IV (fig. 3) 

34 90 

10 56 

6.5 46 

1.5 39.5 

10 38 

12 28 

11 16 

5 5 

Hill west of Clay Slide, through massive carbonate buildup 

about 400 ft south of Section RC III. 

CumuThickness lative 

Road Canyon Formation (ftl (ft) 

6. Conglomeratic limestone, orange-gray wackestone, massive bed with sponges, Coscinophora; barren conodont sample at 98 ft. . . . 5 100 

5. Partly covered, silty conglomeratic wackestone .................................. . 

4. Limestone, orange-gray wackestone, Coscinoplzora bank, and some conglomerate; barren 

conodont sample at 80 ft ................ . 

3. Limestone, light-gray to orange, silty, crinoidal, dolomitic wackestone with chert nodules; massive, becoming conglomeratic 

upward; Coscinophora bank at 65 ft; conodont sample at 67 ft .................... . 

2. Dolostone, light-brownish-gray, silty, crinoidal dolowackestone, massive. localized lens 

with rusty chert nodules ................. . 

1. Limestone, light-olive-gray, skeletal wackestone to packstone. crossbedded, locally 

conglomeratic with clasts within clasts; 

sponges, corals, bryozoans; Coscinophora 

banks at 35, 25, 15 ft; conodont samples at 

3, 2.5 ft; barren samples at 39, 17 ft. ..... 

10 

5 

30 

10 

40 

A 14 Shorter Contributions to Paleontology and Stratigraphy 

95 

85 

80 

50 

40 

Section RC V (fig. 3) 

Same hill that contains Clay Slide, but on knob north of the 

slide; slumped Cathedral Mountain siltstone and mudstone capped 

by Road Canyon limestone. 

CumuThickness lative 

Road Canyon Formation 

5. Limestone, silty lime mudstone with scattered 

rusty chert nodules, thin, platy bedded; few 

fossils, corals, crinoid columnals, brachiopods; forming ledge capping hill; barren 

(ft) (ft) 

conodont samples at 77, 49 ft . . . . . . . . . . . . 33 81 

4. Limestone. cherty, silty lime mudstone, platy 

and wavy bedded, chert in rusty layers with 

sparse thin interbeds of silty skeletal wackestone with crinoid debris and brachiopods; 

conodont sample at 36.5 ft . . . . . . . . . . . . . . . 18 48 

3. Chert and limestone. interbedded, tan, very 

fine-grained, sandy lime mudstone and 

chert, chert probably replaced siltier layers, 

thin wavy bedded chert diminishing upward 24 30 

2. Conglomeratic limestone. brownish-gray skeletal pack- to wackestone with limestone and 

siltstone clasts; irregular lens; sponges, bryozoans, brachiopods (Meekella, Neospirifer, Peniculauris); conodont sample at 4.5 ft 2.5 6 

1. Limestone and chert, interbedded, silty lime 

mudstone and silty spicular chert, platy and 

wavy bedded............................ 3.5 3.5 

Section RC VI (fig. 3) 

Just above south flank of Clay Slide. 

CumuThickness lative 

Road Canyon Formation (ftl (ftl 

6. Limestone, silty, sandy, skeletal lime mudstone, thin-bedded with sponges and chert 

replacements of sponges, chert along bedding planes and joints; conodont sample at 

87 ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 91 

5. Limestone, silty, skeletal lime mudstone with 

crinoid debris, chonetid brachiopods, platy 

bedded; barren conodont sample at 72 ft . . 20 74 

4. Limestone, skeletal lime mudstone with chert 

on bedding planes, some bedded chert thinbedded; crinoid debris, corals, gastropods, 

brachiopods are rare, chonetid bed 

(Dyoros?) at 55 ft; conodont sample at 50.5 

ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 54 

3. Limestone, silty, skeletal wackestone with 

chert nodules, in massive irregular lens 

ranging from 2 to 15 ft thickness within 30 

ft of section; conodont sample at 30 ft . . . . 5 31 

2. Limestone, silty, skeletal lime mudstone like 

unit 1 with sparse thin skeletal wackestone 

lenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 26 

1. Limestone, silty, skeletal lime mudstone with 

thin rusty chert along bedding planes, thinto medium-bedded with thin siltier horizons 

forming wavy interbeds; crinoid columnals, 

corals, brachiopods (Echinauris, Hustedia, 

others), forms base of cliff above Clay 

Slide; barren conodont sample at 5 ft . . . . . 15 15 
Section RC VII (fig. 4) 

South face of hill facing Hess Canyon, due north of the west 

end of the hill that lies just north of the Hess house; the east end 

of the hogback that contains the type section of the Road Canyon 

Formation. 

CumuThickness lative 

Word Formation (ft) (ft) 

11. Limestone, skeletal packstone with corals, 

sponges, crinoid columnals, brachiopods, 

and limestone clasts; conodont sample at 

top, 130 ft. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 

10. Siltstone, orange, thin-bedded with few thin 

carbonate beds . . . . . . . . . . . . . . . . . . . . . . . . . . 16 129 

Road Canyon Formation 

9. Limestone, light-brownish-gray, skeletal 

wackestone with carbonate clasts up to boulder size, thick- to massive-bedded; sponges, 

corals, brachiopods (Derbyia, Echinauris, 

Hustedia, Meekella, patches of Coscinophora); conodont samples at 112, 89 ft.... 28 113 

8. Mostly covered, apparently orange siltstone 11 85 

7. Limestone, light-tan-gray peloid packstone 

with thin rusty chert stringers, blocky, 

medium-bedded; corals, fusulinids, siltstone 

breaks; conodont sample at 70 ft.......... 14 74 

6. Covered, probably orange siltstone. . . . . . . . . . 7 60 

5. Limestone, light-tan, sandy, skeletal packstone, massive, large Coscinophora banks, 

large crinoid columnals; barren conodont 

sample at 49 ft . . . . . . . . . . . . . . . . . . . . . . . . . . 17 53 

4. Limestone, brown-orange skeletal wackestone, massive, large Coscinophora banks, 

either one or several piled up; corals, 

sponges, fusulinids, mudstone clasts; conodont samples at 35. 27 ft: barren samples at 

35, 19, 18ft............................ 19 36 

3. Limestone, lens of light-brownish-gray to 

orange, silty, skeletal packstone; crinoid 

columnals, sponges, corals, brachiopods 

( Composita, Hustedia, a richthofeniid), 

most fossils broken; conodont sample at 

13.5 ft.................................. 0-5 17 

2. Covered, possibly yellow siltstone . . . . . . . . . . 15 17 

1. Limestone, medium-brownish-gray, skeletal 

wacke- to packstone; a small mound with 

sponges, corals, bryozoans, brachiopods 

(Composita, Coscinophora, Meekella, 

Neospirifer, a richthofeniid, Spiriferellina); 

conodont sample at 1. 5 ft . . . . . . . . . . . . . . . . 2 2 

Section RC VIII (fig. 4) 

Williams Bar-Crescent Ranch (formerly Appel Ranch) just 

east of the Old Word Ranch site, near USNM localities 703a, c, of 

Cooper and Grant (1972). 

CumuThickness lative 

Word Formation 

7. Limestone, silty lime mudstone, very thinbedded, some cross-laminated, blocky 

weathering, chert stringers along some bedding planes; few fossils; barren conodont 

sample at 59 ft ......................... . 

(ft) (ft) 

17 76 

6. Covered, thin-bedded yellow siltstone ...... . 

5. Siltstone, yellow, thin-bedded with stringers 

of silty lime mudstone; barren conodont 

sample at 39 ft ......................... . 

4. Covered, probably yellow siltstone ......... . 

Road Canyon Formation 

3. Limestone, skeletal peloid wacke- to packstone weathering as rounded carbonate 

mounds; abundant fossils with clusters of 

richthofeniids ( Cyclacantharia), Edriosteges, and many other brachiopods; conodont samples at 30.5, 29.5, 27 .5, 26 ft; 

barren sample at 28.5 ft. ................ . 

Cathedral Mountain Formation 

2. Mostly covered, yellow siltstone at 20 to 25 ft 

1. Limestone, light-brownish-gray crinoidal 

packstone with fusulinids and few brachiopods, graded with large crinoid columnals at 

base, more finely broken crinoid debris 

upward, a wackestone at top; conodont sample at 1. 5 ft ............................ . 

Section RC IX (fig. 3) 

18 59 

6 41 

4 35 

6 31 

23 25 

2 2 

East flank of Sullivan Peak, on lower slopes directly under 

the peak itself. 

CumuThickness lative 

Word Formation (ft) (ft) 

18. Limestone, skeletal wackestone, about 40 percent angular carbonate fragments and 60 

percent lime mud (all is Word siltstone 

above this bed); conodont sample at 291 ft 2 292 

17. Partly covered, yellow siltstone. . . . . . . . . . . . . 8 290 

16. Limestone, skeletal wacke- to packstone, 

thick-bedded; peloids, sponges, mudstone 

pebbles; conodont sample at 281.5 ft. . . . . . 2 282 

15. Partly covered, platy yellow siltstone . . . . . . . 6 280 

Road Canyon Formation 

14. Limestone, light-brownish-gray packstone 

with carbonate clasts, massive-bedded; corals, sponges, fusulinids, brachiopods (Coscinophora fragments, Hustedia); conodont 

sample at 272.5 ft. . . . . . . . . . . . . . . . . . . . . . . 7 274 

13. Partly covered, platy yellow siltstone . . . . . . . 11 267 

12. Limestone, medium-brownish-gray, finegrained pack- to grainstone, medium- to 

thin-bedded with angular carbonate fragments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 256 

11. Limestone, medium-brownish-gray packstone, massive-bedded, angular carbonate 

clasts of sand to gravel size, chert; corals, 

chertified sponges, fusulinids, brachiopods 

(Coscinophora); conodont sample at 251.5 

ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 253 

10. Limestone and siltstone, silty skeletal lime 

mudstone interbedded with siltstone, black 

chert nodules; corals, fusulinids, and brachiopods (Megousia); conodont sample at 246 

ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 247 

9. Siltstone, yellow with limestone stringers, 

lowermost bed is limestone with chert on 

upper bedding surface; barren conodont 

sample at 195 ft ........................ . 

8. Limestone and siltstone, interbedded, both 

44 235 

Conodont Biostratigraphy of the Permian Road Canyon Formation A 15 
have thin, platy bedding ................ . 

7. Limestone, very silty, brown-gray lime mudstone, becoming siltier upward; barren conodont sample at 160 ft ................... . 

6. Limestone and siltstone, silty lime mudstone 

interbedded with siltstone; fossils and chert 

scarce; barren conodont samples at 144. 

139.5, 114ft ........................... . 

5. Limestone, cherty, silty, medium-brown-gray 

lime mudstone. blocky weathering; barren 

conodont sample at 95 ft ................ . 

4. Limestone, medium-brown skeletal packstone 

with chert stringers. medium-bedded; some 

corals, fusulinids, crinoids; conodont sample at 74 ft. ............................ . 

3. Limestone and siltstone, silty lime mudstone, 

thin- to medium-bedded, interbedded with 

siltstone ............................... . 

2. Covered ................................. . 

1. Limestone, medium-brownish-gray skeletal 

wackestone with lime-mudstone clasts, 

massive-bedded, lenticular; abundant fossils, fusulinids, sponges, corals, bryozoans, 

crinoids, brachiopods; conodont sample at 

16 191 

30 175 

50 145 

17 95 

5 78 

28 73 

30 45 

5, 0 ft .................................. 0-15 15 

Section RC X (fig. 4) 

West side of Hill 5611. near USNM locality 706 of Cooper 

and Grant (1972). 

CumuThickness lative 

Road Canyon Formation (ft) (ft) 

9. Siltstone and limestone. moderate-yellowishbrown, sandy calcareous siltstone irregularly alternating with skeletal crinoidal 

wacke- to packstone (as unit below) and 

yellowish-brown, silty lime mudstone..... 6 61 

8. Limestone, pale-yellowish-brown skeletal 

packstone with abundant crinoid columnals; 

conodont sample at 52 ft. . . . . . . . . . . . . . . . . 13 55 

7. Siltstone, yellowish-orange, thin-bedded. . . . . 5 42 

6. Limestone. pale-yellowish-brown skeletal 

wacke- to packstone with abundant crinoid 

columnals, scattered chert nodules . . . . . . . . 7 37 

5. Limestone. pale-yellowish-brown skeletal 

packstone with abundant fusulinids and 

crinoid columnals; conodont sample at 29 ft 2 30 

4. Limestone. pale-yellowish-brown, slightly 

recrystallized, skeletal wacke- to packstone 

with abundant crinoid columnals. scattered 

chert nodules............................ 13 28 

3. Covered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 15 

2. Limestone, recrystallized skeletal wacke- to 

packstone with abundant crinoid columnals. 

beds pinching and swelling. . . . . . . . . . . . . . . 6 13 

1. Limestone, pinkish-gray. recrystallized, skeletal wackestone (recrystallization due to 

close proximity to Hess Horst bounding 

fault); conodont sample at 1 ft............ 7 7 

Section RC XI (fig. 4) 

South face of knob that is USNM locality 702c (Cooper and 

Grant, 1972), includes north-facing dipslope. 

A 16 Shorter Contributions to Paleontology and Stratigraphy 

CumuThickness lative 

Road Canyon Formation (ft) (ft) 

2. Limestone, poorly exposed on dipslope, lightbrownish-gray skeletal wackestone . . . . . . . . 3.5 10 

1. Limestone, light-brownish-gray skeletal 

wackestone. massive-bedded with very fossiliferous lenses throughout but more common near top, lime-mudstone clasts in lower 

2.5 ft; conodont samples at 5.5, 3.5, 0.5 ft 6.5 6.5 

Section RC XII (fig. 4) 

Limestone ledge east of Split Tank above USNM localities 

726y, 726w, 702a', 702a, 702ent, 702un, 702low, 702int, and 

708u (refer to fig. 22 in Cooper and Grant, 1972). 

CumuThickness lative 

Road Canyon Formation (ft) (ft) 

1. Limestone, pale-yellowish-brown skeletal 

wackestone, medium- to thick -bedded; conodont samples at 5.5, 0.5 ft............... 6 6 

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---1979. Youngest Permian conodont faunas from the Great 

Basin and Rocky Mountain regions, in Sandberg, C.A., and 

Clark, D.L., eds., Conodont biostratigraphy of the Great 

Basin and Rocky Mountains: Brigham Young University 

Studies, v. 26, pt. 3, p. 151-163. 

---1984, Conodont paleoecology of the Permian Phosphoria 

Formation and related rocks of Wyoming and adjacent areas: 

Geological Society of America Special Paper 196, p. 

263-281. 

---1986, Paleontology and deposition of the Phosphoria 

Formation: Contributions to Geology, University of Wyoming, v. 24. no. 2, p. 107-142. 

Wardlaw. B.R., and Grant, R.E .. 1987, Conodont biostratigraphy 

of the Cathedral Mountain and Road Canyon Formations, 

Glass Mountains, West Texas, in Cromwell, Dave, and 

Conodont Biostratigraphy of the Permian Road Canyon Formation A 17 
Mazzullo, L.J., eds., The Leonardian facies in W. Texas and 

S.E. New Mexico and guidebook to the Glass Mountains, 

West Texas: 1987 Permian Basin Section, Society of Economic Paleontologists and Mineralogists Publication 87-27, 

p. 63-66. 

Wilde, G.L., 1975, Fusulinid-defined Permian stages, in Permian 

exploration, boundaries, and stratigraphy: West Texas Geological Society and Permian Basin Section of the Society of 

Economic Paleontologists and Mineralogists Publication 

75-65, p. 67-83. 

A 18 Shorter Contributions to Paleontology and Stratigraphy 

Wilde, G.L., and Todd, R.G., 1968, Guadalupian biostratigraphic 

relationships and sedimentation in the Apache Mountain 

region, West Texas, pt. 1, Surface correlations: Symposium 

and Guidebook, 1968 Field Trip, Permian Basin Section, 

Society of Economic Paleontologists and Mineralogists, Publication 68-11, p. 10-31. 

Youngquist, W.L., Hawley, R.W., and Miller, A.K., 1951, 

Phosphoria conodonts from southeastern Idaho: Journal of 

Paleontology, v. 25, p. 356-364. 
PLATES 1-4 

Contact photographs of the plates in this report are available, at cost, from the U.S. Geological Survey 

Photographic Library, Federal Center, Denver, CO 80225. 
Figures 

PLATE 1 

NEOGONDOLELLA 

[All figures x60] 

1-7. Neogondolella serrata (Clark and Ethington). 

1. Oblique upper view, Pa element, USNM 406891, W81169. 

2. Upper view, Pa element, USNM 406892, W81169. 

3. Upper view, Pa element, USNM 406893, W81169. 

4. Oblique upper view, Pa element, USNM 406894, W81176. 

5. Upper view, Pa element, USNM 406895, W81176. 

6. Oblique upper view, Pa element, USNM 406896, W81176. 

7. Upper view, Pa element. USNM 406897, W81174. 

10-13. Neogondolella serrata (Clark and Ethington). 

10. Oblique upper view, Pa element, USNM 406898, W81176. 

11. Upper view, Pa element, USNM 406899, W81176. 

12. Oblique upper view, Pa element, USNM 406900, W81176. 

13. Oblique upper view, Pa element, USNM 406901, W81169. 

17-18. Neogondolella serrata (Clark and Ethington). 

17. Oblique upper view, Pa element, USNM 406902, W81176. 

18. Upper view, Pa element, USNM 406903, W81176. 

8-9. Neogondolella idahoensis (Youngquist, Hawley, and Miller). 

8. Oblique upper view, Pa element, USNM 406904, W81161. 

9. Oblique upper view, Pa element, USNM 406905, W81161. 

14-16. Neogondolella idahoensis (Youngquist, Hawley, and Miller). 

14. Upper view, Pa element, USNM 406906, W81179. 

15. Upper view, Pa element, USNM 406907, W81161. 

16. Oblique upper view, Pa element, USNM 406908, W81179. 

19-22. Neogondolella idahoensis (Youngquist, Hawley, and Miller). 

19. Upper view, Pa element, USNM 406909, W81161. 

20. Oblique upper view, Pa element, USNM 406910, W81161. 

21. Oblique upper view, Pa element, USNM 406911, W81161. 

22. Oblique upper view, Pa element, USNM 406912, W81179. 
U.S. GEOLOGICAL SURVEY BULLETIN 1895-A PLATE 1 

NEOGONDOLELLA 
PLATE 2 

HINDEODUS AND NEOGONDOLELLA 

[All figures x60] 

Figures 1-15. Hindeodus excavatus (Behnken). 

1. Inner view, Sc element, USNM 406913, W81176. 

2. Inner view, Sc element, USNM 406914, W81176. 

3. Inner view, Pb element, USNM 406915, W81176. 

4. Inner view, Pb element, USNM 406916, W81176. 

5. Lateral view, Pa element, USNM 406917, W81176. 

6. Lateral view, Pa element, USNM 406918, W81176. 

7. Inner view, Sc element, USNM 406919, W81176. 

8. Posterior view, M element, USNM 406920, W81176. 

9. Lateral view, M element, USNM 406921, W81176. 

10. Posterior view, Sb element, USNM 406922, W81176. 

11. Posterior view, Sb element, USNM 406923, W81176. 

12. Outer view, Sc element, USNM 406924, W81176. 

13. Inner view, Sc element, USNM 406925, W81176. 

14. Posterior view, Sb element, USNM 406926, W81176. 

15. Outer view, Sc element, USNM 406927, W81176. 

16-19. Neogondolella serrata (Clark and Ethington). 

16. Lower view, Pa element, USNM 406928, W81174. 

17. Lower view, Pa element, USNM 406929, W81176. 

18. Lower view, Pa element, USNM 406930, W81169. 

19. Lower view, Pa element, USNM 406931, W81169. 

23-25. Neogondolella serrata (Clark and Ethington). 

23. Lower view, Pa element, USNM 406932, W81176. 

24. Lower view, Pa element, USNM 406933, W81176. 

25. Lower view, Pa element, USNM 406934, W81176. 

20-22. Neogondolella idahoensis (Youngquist, Hawley, and Miller). 

20. Lower view, Pa element, USNM 406935, W81179. 

21. Lower view, Pa element, USNM 406936, W81161. 

22. Lower view, Pa element, USNM 406937, W81161. 

26-28. Neogondolella idahoensis (Youngquist, Hawley, and Miller). 

26. Lower view, Pa element, USNM 406938, W81161. 

27. Lower view, Pa element, USNM 406939, W81179. 

28. Lower view, Pa element, USNM 406940, W81161. 
U.S. GEOLOGICAL SURVEY BULLETIN 1895-A PLATE 2 

HINDEODUS AND NEOGONDOLELLA 
PLATE 3 

NEOSTREPTOGNA THODUS, HINDEODUS, SWEETOGNATHUS, AND SWEETINA 

Figure 

[All figures x60, except where noted otherwise] 

1. Neostreptognathodus newelli Wardlaw and Collinson. 

1. Upper view, Pa element, USNM 406941, W81228. 

2. Neostreptognathodus clinei Behnken. 

2. Upper view, Pa element, USNM 406942, W81243. 

3-11. Hindeodus excavatus (Behnken). 

3. Upper view, Pa element, USNM 406943, W81176. 

4. Oblique upper view, Pa element, USNM 406944, W81176. 

5. Lateral view, Pa element, USNM 406945, W81176. 

6. Lateral view, Pa element, USNM 406946, W81176. 

7. Lateral view, Pa element, USNM 406947, W81176. 

8. Lateral view, Pa element, USNM 406948, W81176. 

9. Lateral view, Pa element, USNM 406949, W81176. 

10. Lateral view, Pa element, USNM 406950, W81176. 

11. Lateral view, Pa element, USNM 406951, W81176. 

12-17. Sweetognathus iranicus Kozur, Mostler, and Rahimi-Yazd. 

12, 16. Upper view, Pa element, USNM 406952, W81176,x60 and 

enlarged, x 300, showing surface pustules. 

13, 17. Upper view, Pa element, USNM 406953, W81176, X60 and 

enlarged, x 300, showing surface pustules. 

14. Upper view, Pa element, USNM 406954, W81194. 

15. Upper view, Pa element, USNM 406955, W81200. 

18-25. Sweetinafestiva (Bender and Stoppel). 

18. Lateral view, Sa element, USNM 406956, W81165. 

19. Posterior view, M element, USNM 406957, W81176. 

20. Posterolateral view, M element, USNM 406958, W81176. 

21. Posterolateral view, Sb element, USNM 406959, W81162. 

22. Inner view, Sc element, USNM 406960, W81176. 

23. Inner view, Sc element, USNM 406961, W81176. 

24. Lateral view, Sc element, USNM 406962, W81176. 

25. Posterior view, M element, USNM 406963, W81165. 
U.S. GEOLOGICAL SURVEY BULLETIN 1895-A PLATE 3 

NEOSTREPTOGNATHODUS, HINDEODUS, SWEETOGNATHUS, AND SWEETINA 
PLATE 4 

XANIOGNA THUS, NEOSTREPTOGNATHODUS, AND NEOGONDOLELLA 

[All figures x60] 

Figures 1-22. Xaniognathus abstractus (Clark and Ethington). 

1. Posterior view, Sa element, USNM 406964, W81239. 

2. Oblique lateral view, Sa element, USNM 406965, W81176. 

3. Oblique lateral view, Sa element, USNM 406966, W81176. 

4. Posterior view, M element, USNM 406967, W81176. 

5. Anterior view, M element, USNM 406968, W81176. 

6. Posterolateral view, M element, USNM 406969, W81176. 

7. Posterior view, M element, USNM 406970, W81176. 

8. Posterior view, Sb element, USNM 406971, W81176. 

9. Posterior view, Sb element, USNM 406972, W81176. 

10. Posterolateral view, Sb element, USNM 406973, W81176. 

11. Anterolateral view, Sb element, USNM 406974, W81176. 

12. Lateral view, Pa element, USNM 406975, W81176. 

13 . Lateral view, Pa element, USNM 406976, W81176. 

14. Lateral view, Sc element, USNM 406977, W81239. 

15 . Lateral view, Sc element, USNM 406978, W81176. 

16. Lateral view, Sc element, USNM 406979, W81176. 

17. Lateral view, Pa element, USNM 406980, W81176. 

18. Lateral view, Pa element, USNM 406981, W81176. 

19. Inner view, Pb element, USNM 406982, W81176. 

20. Inner view, Pb element, USNM 406983, W81176. 

21. Inner view, Pb element, USNM 406984, W81176. 

22. Inner view, Pb element, USNM 406985, W81176. 

23. Neostreptognathodus sp. 

23. Inner view, Pb element, USNM 406986, W81176. 

24-25. Neogondolella idahoensis (Youngquist, Hawley, and Miller). 

24. Upper view, Pa element, USNM 406987, W81161. 

25. Upper view, Pa element, USNM 406988, W81161. 
U.S. GEOLOGICAL SURVEY BULLETIN 1895-A PLATE 4 

XANIOGNATHUS, NEOSTREPTOGNATHODUS, AND NEOGONDOLELLA 

Chapter B 

The Rugose Coral Ankhelasma -Index to 

Visean (Lower Carboniferous) Shelf Margin 

in the Western Interior of North America 

By WILLIAM j. SANDO, E. WAYNE BAMBER, and BARRY C. RICHARDS 

Predictions of Carboniferous shelf-margin locations 

using the living zone of a rugose coral 

U.S. GEOLOGICAL SURVEY BULLETIN 1895 

SHORTER CONTRIBUTIONS TO PALEONTOLOGY AND STRATIGRAPHY 

CONTENTS 

Abstract Bl 

Introduction Bl 

Acknowledgments B2 

Paleotectonic Setting B3 

Western United States B3 

Western Canada B3 

Stratigraphic, Geographic, and Ecologic Distribution of Ankhelasma B4 

Western United States B4 

Western Canada Bll 

Inferred Shelf-Margin Locations B14 

Western United States B14 

Western Canada B17 

Conclusions B17 

References Cited B17 

Appendixes A-D 

A. Ankhelasma Localities in the United States B19 

B. Control Points for Chronometric Lithofacies Profiles across Known Visean Shelf 

Margin in the United States B24 

C. Ankhelasma Localities in East-Central British Columbia, Canada B24 

D. Control Points for Chronometric Lithofacies Profiles across Inferred Visean Shelf 

Margin in Montana B29 

FIGURES 

1. Map of western North America showing area of Lower Carboniferous sedimentary 

rocks in Western Interior region and Lower Carboniferous paleotectonic 

elements Bl 

2. Photographs of specimens of Ankhelasma Sando, 1961, from the Western Interior 

region of North America B2 

3. Map showing Carboniferous deposits and paleotectonic elements, Western Canada 

basin B4 

4. Geologic map of Visean rocks in Western Interior region of the United States 

showing locations of Ankhelasma occurrences BS 

5. Temporal and stratigraphic distribution of Ankhelasma in the Western United 

States B6 

6. Map showing early Visean (Composite Zones 12 and 13) paleogeography of a part 

of the Western Interior basin in the United States and Ankhelasma occurrences in 

relation to shelf margin and lithofacies B8 

7. Map showing early middle Visean (upper Composite Zone 14) paleogeography of a 

part of the Western Interior basin in the United States and Ankhelasma occurrences 

in relation to shelf margin and lithofacies B9 

Contents Ill 
IV Contents 

8. Chronometric lithofacies profiles across Visean shelf margin in the Western 

United States BlO 

9. Map showing present nonpalinspastic facies distribution of Visean (Composite 

Zones 12 to 14) deposits, east-central British Columbia and Ankhelasma occurrences in relation to shelf margin B12 

10. Stratigraphic cross section showing Ankhelasma occurrences and depositional 

environments in Rundle Group and Besa River Formation, study area, east-central 

British Columbia B13 

11. Diagram showing generalized depositional model of Canadian Early Carboniferous 

carbonate platform B14 

12. Temporal and stratigraphic distribution of Ankhelasma in east-central British 

Columbia Bl5 

13. Chronometric lithofacies profiles from Ankhelasma localities in westernmost Carboniferous outcrops in northwestern Montana to inferred shelf margin B16 

TABLE 

1. Nonpalinspastic distances of Ankhelasma occurrences landward from known 

Visean shelf margin in Western Interior region of the United States B7 
The Rugose Coral Ankhelasma -Index to Visean 

(Lower Carboniferous) Shelf Margin in the Western 

Interior of North America 

By William J. Sando, 1 E. Wayne Bamber, 2 and Barry C. Richards2 

Abstract 

Ankhelasma, a distinctive, endemic, solitary rugose 

coral, lived in a belt presently no more than 75 kilometers 

wide, almost exclusively on the landward side of the 

Visean shelf margin in the Western Interior region of 

western North America. A model of the distribution of this 

coral, based on known, nonpalinspastic distances to the 

shelf margin in rocks of early Visean and early middle 

Visean age, suggests that the living zone of this coral was 

probably no more than approximately 50 kilometers wide. 

The genus originated either in northeastern Utah or 

southwestern Canada at the beginning of the early Visean 

(Composite Zone 12) and migrated both northward and 

southward along the shelf margin, dying out by the end of 

early late Visean (Composite Zone 14) time, a phylogenetic life span of about 8 million years. Occurrences of 

this coral in northwestern Montana and east-central British Columbia adjacent to areas where the Visean depositional record has been removed by subsequent erosion 

are helpful in determining or confirming inferred locations for the shelf margin in these areas. 

INTRODUCTION 

During the Early Carboniferous, the Western Interior 

region of North America was occupied by an epeiric sea that 

extended from arctic Canada to northern Mexico (fig. 1). 

Ankhelasma Sando, 1961 (fig. 2), is a small, curved-conical 

solitary rugose coral, endemic to the Western Interior 

province of Sando and others (197 5, 1977), that is distinguished by the extraordinary development of five septal 

plates in the mature (ephebic) stage. The presence of these 

plates facilitates recognition in transverse section, even 

without laboratory preparation. The genus is represented by 

one nominal species, A. typicum Sando, 1961, in the United 

States and Canada and by at least one unnamed species in 

Canada. Ankhelasma probably evolved from the widespread 

Manuscript approved for publication April 27 , 1989. 1 U.S. Geological Survey, U.S. National Museum of Natural 

History , Washington, DC 20560. 2 Geological Survey of Canada , 3303 33d St., NW., Calgary , 

Alberta, Canada 2TL 2A 7. 

Figure 1. Western North America showing area of Lower 

Carboniferous sedimentary rocks in Western rnterior 

region (stippled) and Lower Carboniferous paleotectonic 

elements. Compiled from Sproule (1958, fig. 1), Poole and 

Sandberg (1977, fig. 1L Sando (1985, fig. 1L and Richards 

and others (in press). Triangles indicate areas that have 

one or more occurrences of Ankhelasma. 

genus Sychnoelasma (Homalophyllites of earlier reports; 

see Sando, 1961, p. 67), a coral that occurs commonly in the 

sequence below the lowest occurrence of Ankhelasma and is 

sparse in the lowermost part of the range of Ankhelasma 

(Sando and Bamber, 1985). 

Preliminary studies of the stratigraphic and geographic distribution of Ankhelasma suggested that it was 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America Bl 
Figure 2. Specimens of Ankhelasma Sando, 1961, from 

the Western Interior region of North America. A, B. 

Calicular and alar views, respectively, x3, of silicified 

corallum of A. typicum, holotype, USNM 120201, from 

USGS loc. 17722-PC, Brazer Dolomite (member 3), Composite Zone 12, Rex Peak, Crawford Mountains, Utah. C, 

D. Calicular and alar views, respectively, x3, of silicified 

corallum of A. typicum, hypotype, USNM 424262, from 

USGS loc. 27968-PC, Monte Cristo Limestone (Yellowpine 

Member), Composite Zone 14, Potosi Mine, Goodsprings 

District, Nevada. £, F. Calicular and alar views, respecrestricted to a narrow geographic zone related to the edge of 

a broad carbonate shelf (shelf margin) during the early to 

early middle Visean in the Western Interior region of the 

United States. A similar distribution pattern was noted in 

western Canada, where exposures of the shelf margin are 

extensive but less completely sampled. 

Because shelf margins define depositional strike 

along basin flanks and influence the character and distribution of petroleum-reservoir rocks and seals, they are of 

prime economic importance (Rose, 1976, p. 449-450). 

Accurate delineation of Carboniferous shelf margins is 

important to the preparation of regional paleogeographic 

maps, which can be used to analyze depositional history . 

Mapping of shelf margins also can be useful for measuring 

later structural offsets and translocations. This paper documents a geographic distribution model for Ankhelasma and 

uses this model to predict or confirm shelf-margin locations 

82 Shorter Contributions to Paleontology and Stratigraphy 

H 

tively, x 3, of silicified corallum of A. n. sp., hypotype, 

GSC 89984, from GSC loc. C-110910, Prophet Formation 

(member B), Composite Zone 13 or 14, South Mountain 

Creek, Pine Pass map area, east-central British Columbia. 

G. Transverse thin section, x 3, of A. typicum, hypotype, 

USNM 424263, from USGS loc. 27074-PC, Brazer Dolomite 

(member 2), Composite Zone 12, Trail Hollow, Uinta 

Mountains, Utah. H. Thin section of Ankhelasma-bearing 

bed showing A. typicum and associated fossils in packstone, x2, same locality as G. 

in areas where the depositional record has been removed or 

obscured by later events. 

Acknowledgments 

Early field work by the senior author on the stratigraphy of Ankhelasma was done largely with J.T. Dutro, Jr., 

whose companionship and contributions to the stratigraphy 

are gratefully acknowledged. Ten years of joint field studies 

with C.A. Sandberg and R.C. Gutschick laid the foundation 

for sophisticated analysis of the shelf margin; the creative 

and inspiring conceptual contributions of these colleagues 

strongly influenced many of the ideas expressed in this 

paper. E.E. Bierwagen, J.A. Dockal, M .R. Mudge , C.A. 

Sandberg, and Betty Skipp contributed samples of 

Ankhelasma to the senior author. Shell Canada Limited 

supplied specimens and information from several localities 
in Canada. Conodont identifications and zonal determinations were made by C.A. Sandberg for samples from the 

United States, and A.C. Higgins was responsible for 

the same information on Canadian samples. Identifications 

of foraminifers and algae and zonal determinations on 

samples from the United States and Canada were made by 

B.L. Mamet. 

PALEOTECTONIC SETTING 

Western United States 

Previous studies of Devonian and Carboniferous 

geology in the Western United States (Poole, 1974; Nilsen, 

1977; Poole and Sandberg, 1977) showed that the Western 

Interior basin was located at the edge of the North American 

protocontinent and that the basin was affected by Late 

Devonian and Early Carboniferous plate collision (Antler 

orogeny). A broad, shallow, epicontinental sea, located on 

the craton (cratonic platform), was bounded on the east by 

the Transcontinental arch, a positive area of Precambrian 

crystalline rocks and lower Paleozoic sedimentary rocks 

that formed a peninsula during the Early Carboniferous and 

separated the Western Interior and Eastern Interior basins 

(fig. 1) (Gutschick and Sandberg, 1983). An island chain 

composed of uplifted early Paleozoic rocks was formed in 

the Antler orogenic belt during plate collision and bounded 

the Western Interior basin on the west. Plate collision also 

produced a deep trough (Antler foreland basin) between the 

Antler orogenic belt and the stable cratonic platform during 

the Visean. 

Deep-water terrigenous and carbonate sediments 

deposited in the Antler foreland basin were separated from 

shallow-water carbonate and evaporitic sediments of the 

cratonic platform by a narrow break in depositional slope, 

called shelf margin by previous workers (Rose, 1976; 

Sando, 1976; Gutschick and others, 1980; Sandberg and 

others, 1982; Gutschick and Sandberg. 1983). The geographic position of the Mississippian shelf margin changed 

through time, but the shelf margin was always close to the 

craton margin. Ankhelasma has been found only in a narrow 

belt that follows the frontal zone of Laramide thrusting. 

approximately coincident with the craton margin and 

Visean shelf margin. from southeastern Nevada to northwestern Montana (fig. 1). 

Western Canada 

Canadian occurrences of Ankhelasma are of the same 

age as those in the United States and occupy similar 

geographic positions with respect to the craton margin and 

Visean shelf margin (figs. 1 and 3). Strata containing 

Ankhelasma were deposited in the southwestern part of the 

Peace River embayment and in the Prophet trough to the 

west and south. Although the distribution pattern is similar. 

there are still some uncertainties concerning exact relations 

with paleotectonic elements recognized in the United 

States. 

The name Prophet trough was introduced by Richards 

and others (in press) for an extensive, northwest-trending, 

downwarped and downfaulted belt that developed on the 

western margin of the North American protocontinent 

during the latest Devonian and Carboniferous. The trough 

was continuous with the Antler foreland basin and extended 

from southeastern British Columbia into the northern part of 

the Yukon Territory. A broad hinge zone, marking a point 

at which water depths and sedimentation rates increased 

rapidly basinward, formed the boundary between the 

Prophet trough and the cratonic platform to the east. The 

western boundary of the trough was an elevated rim, at least 

locally subaerially exposed during the Early Carboniferous. 

The Antler orogenic belt of the United States, or a related 

orogenic belt, may have extended at least as far north as the 

southern part of the Peace River embayment, thereby 

forming part of the western rim of the southern Prophet 

trough (Richards and others, in press). The origin of the 

trough is not well established. Some workers (TemplemanKluit, 1979; Gordey and others, 1987; Struik, 1987) believe 

that the trough is either partly or predominantly an extensional feature resulting from Late Devonian and Early 

Carboniferous rifting of western North America. Extension, 

recorded by extensive block faulting, did occur in the 

central part of the Prophet trough and in the Peace River 

embayment (Richards and others. in press). However, 

tectonic and sedimentologic data summarized by Richards 

and others (in press) suggest that the Antler orogeny or a 

related compressional event influenced the marked Tournaisian and Visean subsidence that occurred in the southern 

part of the trough. 

In northwestern Alberta and northeastern British 

Columbia, the Peace River embayment, a broad reentrant 

into the cratonic platform, opened westward into the 

Prophet trough (figs. 1 and 3). The depositional and 

structural axis of this arcuate embayment had an easterly 

trend and coincided approximately with the axis of the Late 

Devonian Peace River arch. Extensive block faulting, 

accompanied by regional flexural subsidence, produced the 

embayment, which is characterized by an anomalously 

thick Lower Carboniferous sequence and by numerous 

northeasterly and northwesterly striking syndepositional 

and postdepositional normal faults. Evidence for westward 

shallowing during the Tournaisian and Visean indicates that 

a slightly positive area, possibly a series of islands or a 

peninsula, was at least periodically present in the southwestern part of the Peace River embayment when strata 

containing Ankhelasma were deposited. Parts of this 

northwest-trending positive area, which extended well 

southeastward of the embayment, were intern1ittently elevated and exposed to subaerial erosion during the earliest 

middle Toumaisian (earliest Tn2) to Serpukhovin. All 

Ankhe/asma-lndex to Visean Shelf Margin, Western Interior of North America 83 
60° 

55° 

50° 

0 

I 

EXPLANATION 

Middle Tournaisian to Upper Visef.n shelf and 

basinal deposits (Rundle Gp., Be sa RiverFm., 

Middle and Upper Madison Gp.) 

Carboniferous deposits formed on western flank 

of Prophet trough and in marginal basin to west 

Intermittently positive area during earliest middle 

Tournaisian to Serpukhovian 

Approximate location of eastern margin of Prophet 

trough and Peace River embayment during late 

Tournaisian and early Visean 

Approximate location of western margin of 

Prophet trough 

Margins of Carboniferous tectonic elements 

Eastern limit of disturbed belt (Cordillera) 

Fault, arrow shows relative direction of movement 

Figure 3. Carboniferous deposits and paleotectonic elements, Western Canada basin (after Richards and others, in 

press). Study area contains all known Canadian occurrences of Ankhelasma (see fig. 9). 

known Canadian occurrences of Ankhelasma are in carbonate rocks deposited on or near the positive region. 

STRATIGRAPHIC, GEOGRAPHIC, AND 

ECOLOGIC DISTRIBUTION OF ANKHELASMA 

Western United States 

In the United States, Ankhelasma occurs at 17 surface 

localities in a narrow belt (Ankhelasma belt) along the 

western margin of the cratonic platform (fig. 4) (see 

appendix A for complete descriptions of localities). The 

spacing of occurrences along the strike of the Ankhelasma 

belt seems to be determined mainly by availability of 

outcrops of rocks potentially bearing Ankhelasma; this 

relation is most notable in the long stretch of land having no 

occurrences from the southwestern comer of Utah to northeastern Utah, where rocks potentially bearing Ankhelasma 

do not crop out. Consequently, Ankhelasma is not recorded 

from this area, although no subsurface cores have been 

examined by the writers. 

More than 30 years of intensive collecting of corals 

by the senior author outside the area herein designated 

Ankhelasma belt, as well as hundreds of collections sent to 

84 Shorter Contributions to Paleontology and Stratigraphy 

the senior author for study by other geologists, have failed 

to reveal even a single specimen of the genus. Moreover, 

examination of hundreds of collections of Lower Carboniferous rocks made by geologists of the U.S. Geological 

Survey during the past 80 years revealed only two occurrences of this unique coral, and these were both in the 

narrow belt revealed by more recent field work. 

Ankhelasma occurs in two stratigraphic intervals in 

the United States (fig. 4). In northeastern Utah, western 

Wyoming, southeastern Idaho, and western Montana, the 

occurrences are all dated as early Visean (Composite Zones 

12 and 13 of Sando, 1985) by foraminifers, corals, and 

conodonts (localities 4-8, 10-13). In south-central Idaho, a 

poorly dated debris-flow occurrence (locality 9) is also 

thought to be from the same interval. In southeastern 

Nevada and northwestern Arizona (localities 1-3), the 

occurrences are of early middle Visean age (Composite 

Zone 14 of Sando, 1985). 

A more detailed analysis of stratigraphic distribution 

(fig. 5) shows that the earliest known occurrences of 

Ankhelasma in the United States are at the base of Composite Zone 12 at localities 4 and 5 in the Uinta Mountains 

of northeastern Utah. The genus ranges through Composite 

Zone 12 well into Composite Zone 13 along the 

Ankhelasma belt to the northwest in western Wyoming, 

southeastern Idaho, and western Montana (localities 6-13). 
FORELAND 

BASIN 

100 MILES 

I 

0 100 KILOMETERS 

EXPLANATION 

VISEAN DEPOSITIONAL AREAS 

F:3 

L3 

Outcrop of older rocks where 

Visean rocks were removed 

by subsequent erosion 

Visean rocks preserved in surface 

and subsurface (includes small areas 

removed by subsequent erosion) 

Visean rocks mostly obscured by 

Cretaceous-Tertiary sedimentary, 

extrusive, and intrusive rocks 

VISEAN POSITIVE AREAS 

Visean rocks never deposited 

(includes some areas removed by 

subsequent erosion). Dashed lines 

indicate inferred extensions of 

positive areas 

Post-Visean lateral fault, dashed 

where inferred. Arrows indicate 

relative direction of movement 

Post-Visean thrust fault, dashed 

where inferred. Sawteeth on 

upper plate 

Southern limit of 

Pre-Jurassic truncation 

Ankhelasma occurrences * Composite zone 14 

® Composite zone 12 or 13 

1*1 Debris flow, Composite zone 12 

Area of map 

Figure 4. Geologic map of Visean rocks in Western Interior region of the United States showing locations of Ankhelasma 

occurrences. Modified from Craig and Connor (1979, pl. 2) and Sandberg and others (1982, fig. 2). 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 85 
340-

-

-

-

-

rJ) 

:J 

0 

0::: t±: 345- ~ 

z -'U.l z 

rJ) <t: ~ - 5 5: 

0::: - 0... 

<t: {]) u - rJ) 

{]) ffi 350- rJ) 

TIME SCALES 

zrJJ 

<t:~ uo::: -u.l CCifJ 

u.l--l 

~<t: <t:-

:r:~ r-- o:::> 

oo z8: 

? 

0::: 

u.lrJ) 

W..u.J zz -o 

~N 

~Q oe!:l 

w.. 

1----

13 

12 

-

11 

1----

10 

CONODONT 

BIOZONES 

Taphrognathus 

varians 

Gnathodus 

texan us 

rJ) 

u.l 

z 

0 

N 

0 

53 

--l 

~ 0 

u 

rJ) 

u.l 

z 

0 

N 

0 

53 

u.l 

r-

{1) 

0 

0... 

~ 

0 

u 

17 

Dr------

16 

c 15 

1 

POTOSI 

MINE 

Sec. 12, 

T. 23S, 

R. 57E 

Clark 

County, 

Nevada 

Yellowpine 

Member 

2 

TUNGSTEN 

GAP 

Sec. 10, 

T. 15S, 

R.64E 

Clark 

County, 

Nevada 

Yellowpine 

Member 

3 

VIRGIN 

RIVER 

GORGE 

Secs.20 

and 30, 

T. 41N, 

R 14W 

Mohave 

County, 

Arizona 

Yellowpine 

Member 

B 14 ~ ® ~ ® ~ ? ® 0 .g 0 1---c---,--------,------i III "'@ Arrowhead ~ Arrowhead "'@ Arrowhead 

1----+-----l E h Member ,_ E h Member ,_ E -, Member ~ ~ ~ 

13 il 

·c 

u Ar---(l) 

1: 

12 ~ 

Bullion 

Member 

Bullion 

Member 

0 

tl 

·c 

u 

~ Bullion 

~ Member :s -1/zl ~ o _u~ l 

--l :£2 - Z ~-----~1 Scaliognathus anchoralis-\'-+----+----l----1 

<r:~ ~ ~ 9 Doliognathus latus - z til 

cc..B- - :J 

355- 12 

<t: -3 8 CJ ~ 1---+--------------,~----1 II 

~ _ Gnathodus typicus Anchor Mbr. Anchor Mbr. Anchor Mbr. 

Dawn Mbr. Dawn Mbr. Dawn Mbr. 

Figure 5. Temporal and stratigraphic distribution of Ankhelasma in the Western United States. Time scales from Sando 

(1985). Coral symbols indicate positions of Ankhelasma at each locality. See figure 4 for geographic locations and 

appendix A for descriptions of localities. 

To the southwest, the genus appears again in Composite 

Zone 14 in northwestern Arizona (locality 3) and in southeastern Nevada (localities 1 and 2). 

Nonpalinspastic paleogeographic maps for Composite Zones 12 and 13 (fig. 6) and upper Composite Zone 14 

(fig. 7) reveal plausible explanations for the geographic and 

stratigraphic distribution patterns of Ankhelasma noted 

above. These maps are a revision of maps of slightly 

different time intervals published previously by Sandberg 

and others (1982, figs. 16 and 17). Because a lack of 

outcrop and the influence of major thrust faults prevent 

actual observation of the exact shelf-margin positions, 

locations of the Visean shelf margin are documented by a 

series of nonpalinspastic chronometric lithofacies profiles 

across the areas of regional facies change (fig. 8; appendix 

B). Precise locations of shelf-margin positions must be 

inferred by projection of on-shelf and off-shelf lithofacies 

from section control points on either side of the margin. 

Structural telescoping by thrust faulting undoubtedly distorted pre-Laramide depositional distances, particularly in 

86 Shorter Contributions to Paleontology and Stratigraphy 

the northern part of the thrust belt, and major transverse 

faults offset the shelf margin at several places (figs. 6 and 

7). Nevertheless, the regional pattern of demarcation 

between deep-water basinal sedimentation west of the 

margin and shallow-water shelf sedimentation east of the 

margin can be seen clearly on the maps and profiles. 

Early Visean (Composite Zones 12 and 13) time was 

characterized by a continuous area of shelf carbonate 

sedimentation extending from Montana to Arizona (fig. 6). 

This area was divided into a northern Madison shelf and a 

southern Leadville-Redwall shelf; these shelves are named 

for formations or groups that include rocks of Visean age in 

the respective areas. Both shelves were characterized by 

mostly open-marine subtidal carbonate and evaporite deposition in predominantly intertidal and supratidal environments in northeastern Utah and southwestern Wyoming. 

Deposition seaward from the shelf margin was characterized by deep-water carbonate and terrigenous sediments of 

the Deseret starved basin, Chainman basin, and Middle 

Canyon-McGowan Creek basin (see Gutschick and others, 
ANKHELASMA OCCURRENCES 

4 5 6 7 8 9 10 11 12 13 if) ~------+-------~-------+--~---4--------~------+-------~-------4--------~----~ WJ 

CRAWFORD CHAMBER BIG UTILE Z 

TRAIL MOUNTAINS HAYSTACK SHEEP LAIN - SHEEP BELL BLACKFOOT HANNAN 0 

HOLLOW COMPOSITE PEAK CREEK CREEK CREEK CANYON RIVER GULCH N 

~-8 0 

SAMAK 

Sec. 25, 

T. 2S, 

R.6E 

Summit 

County, 

Utah 

Sec. 33, 

T. 3S, 

R.9W 

Wasatch 

County, 

Utah 

Sec. 6, 

T. 10N, R. 8E 

and 

Sees. 17, 20, 

29 and 31, 

T. 11N, R. 8E 

Rich 

County, 

Utah 

Sec. 27, 

T. 34N, 

R. 117W 

Lincoln 

County, 

Wyoming 

Sec. 28, 

T. lN, 

R. 45E 

Bonneville 

County, 

Idaho 

£ Horseshoe 

Sec. 20, 

T. 14N, 

R.29E 

Beaverhead 

County, 

Montana 

Scott 

Peak 

Sec. 22, 

T. 14S, 

R.10W 

Beaverhead 

County, 

Montana 

Sec. 17, 

T. 11S, 

R.10W 

Beaverhead 

County, 

Montana 

Sec. 29, 

T. 11N, 

R.6W 

Lewis 

and Clark 

County, 

Montana 

Sec. 35, 

T. 22N, 

R.9W 

Teton 

County, 

Montana 

co 

WJ 

r-

(1) 

0 

0... 

~ 

0 

u 

17 

Humbug 

Formation ~ Shale Formation 

~ Member r---------7---- <( 

Kibbey 

Formation 

Kibbey 

Formation 16 

Humbug 

Formation 

I-~?-

Not 

Exposed 

Humbug 

Formation ~~?----~--?----

McKenzie McKenzie 

Canyon Canyon 

~ Equivalent ~ Equivalent 

f----~7---- il f------7---- il f----------j 

()) ()) 

E E 

.:.::l .:.::l 

2 Upper 2 2 § U § Upper ·E- b - ·- Upper ~ pper ~ member o mem er .E Upper E .... .... 0 o member U<ll member U<ll ?fro, 8 o member o \JI) 

... <ll ?fro, C?l _ ~ ~ Mission '=-- '? _ \JI) ?fro, ·-§ \_\!) ?fro, ·-§~ pper 

~ Mission \JI) ~ Canyon Eq.(fl ~ f----------j .~ I ~ .~ evaporite 

co Canyon Eq. d5 d5 Mission ~ ~ m-::,~:~:n \_ ~ evaporite Lower 

r---?-----1--------~ 

McKenzie 

Middle Canyon 

McKenzie 

Canyon 

Canyon Limestone Limestone 

Formation ~,------?---+-~----

f-------

Hiatus Hiatus 15 

14 

~ § Upper 

? <ll Upper gj member (fJ '-

~ E member .§f--?~ 

7'..A-'--'-,___o'-.· J-su"}~Rive~ 13 

(fJ e Member tfJ ~Wu~v"E!l ~ t1J § · (fJ 

? 2' :;:>, 

• ell ~ Lower 

~ Lower ~ member 

.~"'- member .Q 

~ 

Mission 

Canyon 

Limestone 

()) f----

~ 1-----------j 

()) Lower 

~ member u 

12 

-

11 Tetro Eq. Canyon Eq. Lower 

Delle Mbr. Not Tetro Eo. member member ~ ~ -?--------i____j__--?---+-_L_--~ 

McGowan 

Creek 

Formation 

Allan 

Mountain 

Limestone 

-

Madison Exposed f---l---'D"-"e""lle"--M'-'-'-"-'br,_._. -+-__j__--------i 

Limestone Lodgepole Ls. Lodgepole Ls. Lodgepole Ls. 

Figure 5. Continued. 

1980; Sandberg and others, 1982; and Sandberg and Gutschick, 1984, for descriptions of these sediments). 

During the early Visean (Composite Zones 12 and 

13), Ankhelasma lived in subtidal environments near the 

shelf margin (figs. 6 and 8) on the Madison shelf (upper 

member of Mission Canyon Limestone; fig. 5) and in 

open-marine incursions into the area of restricted shelf 

sedimentation (upper member of Brazer Dolomite; fig. 5). 

The temporal and areal distribution of Ankhelasma (figs. 5 

and 6) suggests that the genus originated in northeastern 

Utah at the beginning of Composite Zone 12 time and 

migrated rapidly both northward and southward along a 

zone that extended approximately 50 km landward from the 

shelf margin (table 1). The exception is locality 9 in 

south-central Idaho, where Ankhelasma occurs approximately 10 km seaward from the shelf margin in a debris 

flow of coarse-grained crinoidal packstone that flowed 

down the slope into deep-water carbonate sediments of the 

Middle Canyon Formation. However, the northeastern Utah 

origin point is not confirmed by the distribution of 

Ankhelasma in Canada, where this coral also occurs at or 

Middle Canyon Middle Canyon 

F . F . e-----?---- ormation ormation Lodgepole Ls. 

10 

9 

Table 1. Nonpalinspastic distances of Ankhelasma occurrences landward from known Visean shelf margin in 

Western Interior region of the United States 

[Asterisk indicates unique debris flow on slope seaward from shelf margin. 

See figures 4, 6, and 7 for geographic locations] 

Occurrence Distance from shelf 

margin (km) 

Composite Zone 12 

Locality 4 

Locality 5 

Locality 6 

Locality 7 

Locality 8 

Locality 9* 

Locality 10 

Locality 11 

Composite Zone 

Locality 11 

Composite Zone 

Locality 1 

Locality 2 

Locality 3 

25 

50 

10 

25 

30 

10 

7.5 

25 

13 

25 

14 

60 

30 

40 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 87 
EXPLANATION 

D Visean depositional record lost or 

obscured by later events 

GJ Visean rocks never deposited or 

removed by later erosion 

Thin basinal facies on highs or 

rises, later eroded 

Open marine shelf facies 

[[SIJ 

~ Restricted shelf 

rn Open marine basin facies 

§_ !_ ~j Starved basin facies 

~~] Flysch facies 

Post-Visean lateral fault, dashed 

where inferred. Arrows indicate 

relative direction of movement 

---~,____..,- Post-Visean thrust fault, dashed 

where inferred. Sawteeth on 

upper plate 

---- • • • Shelf margin 1. Dashed where 

approximate, dotted where inferred 

A 

• 

A' 

• 

Chronometric lithofacies profile 

shown on figs. 8 and 13 

Control points in vicinity of shelf margin 

• Actual 

0 Inferred 

Ankhelasma occurrences 

~ In situ on shelf 

1*1 In debris flow 

0 

I 

0 

I 

50 

50 100 MILES I 

I I 

100 KILOMETERS 

Figure 6. Early Visean (Composite Zones 12 and 13) paleogeography of a part of the Western Interior basin in the United 

States and Ankhelasma occurrences in relation to shelf margin and lithofacies. Modified from Sandberg and others (19C2, 

fig. 16). 

88 Shorter Contributions to Paleontology and Stratigraphy 
MADISON 

KARST 

• 

D 

~ 

D 

E:3 

tm 

EJ 

bEd 

rn 

0 

[~8~ 

EXPLANATION 

Visean depositional record lost or 

obscured by later events 

Visean rocks never deposited or 

removed by later erosion 

Subaerially exposed karst plain 

Thin basinal facies on highs or 

rises, later eroded 

Sabkha facies 

Deltaic facies 

Open marine shelf facies 

Open marine basin facies 

Starved basin facies 

Molasse facies 

Post-Visean lateral fault, dashed 

where inferred. Arrows indicate 

relative direction of movement 

_..._ Post-Visean thrust fault, dashed 

where inferred. Sawteeth on 

upper plate 

---- Shelf margin 2, dashed where 

approximate 

L..LLLLI...L.LLU Shoreline (zero edge), dashed where 

approximate, dotted where inferred. 

Hachures on landward side 

A 

• 

A' 

• 

Chronometric lithofacies profile 

shown on figs. 8 and 13 

Control points in vicinity of shelf margin 

• Actual 

0 Inferred 

* Ankhelasma occurrences 

50 100 MILES 

I 

I I 

0 50 100 KILOMETERS 

Figure 7. Early middle Visean (upper Composite Zone 14) paleogeography of a part of the Western Interior basin in the 

United States and Ankhelasma occurrences in relation to shelf margin and lithofacies. Modified from Sandberg and 

others (1982, fig. 17). 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 89 
345 

350 

355 

340 

345 

350 

340 

m 

B 

r=o 

L8 

~ 

~ 

rn 

EC3 

EXPLANATION 

Sabkha and restricted 

shelf facies 

Intertidal flat facies 

Deltaic facies 

Open marine shelf facies 

Clinoform ramp facies 

Open marine basin and 

slope facies 

Starved basin facies 

Shelf margin positions 

shown on figures 6 and 

7 designated by SM 1 and 

SM2, respectively, at tops 

of profiles and by X's in 

profiles. 

HORIZONTAL SCALE 

0 10 MILES 

l1 1d1 111 11i1 1 I I I 

0 10 KILOMETERS 

Figure 8. Chronometric lithofacies profiles across Visean shelf margin in the Western United States. Geographic 

locations of profiles shown on figures 6 and 7. Control points for these profiles are listed and described in appendix B. 

Ma =million years before present (radiometric scale). CZ =composite zone. 

near the base of Composite Zone 12 at two localities (see 

subsequent discussion in Western Canada section). Evidently, the genus originated either in northeastern Utah and 

migrated rapidly northward, or it originated in British 

Columbia or Alberta and migrated rapidly southward during 

earliest Visean time (migration time estimated at <1 m.y.). 

The lack of outcrops along the shelf margin between 

northeastern Utah and the southwestern corner of Utah 

prevents determination of the southern limit of Ankhelasma 

810 Shorter Contributions to Paleontology and Stratigraphy 

migration during the late early Visean (Composite 

Zone 13). The genus has not been found in the Bullion 

Dolomite Member of the Monte Cristo Limestone in southeastern Nevada and southwestern Utah or in the Mooney 

Falls Member of the Redwall Limestone in northwestern 

Arizona, a distribution that suggests that Ankhelasma had 

not reached the southern part of the shelf at this time. 

However, the occurrence of Ankhelasma in the Y ellowpine 

Member of the Monte Cristo Limestone (upper half of 
Composite Zone 14) suggests that the genus was living in 

the intervening area of no outcrop during the late early 

Visean (Composite Zone 13). 

The early middle Visean (Composite Zone 14) was 

characterized by uplift and subaerial erosion of the northern 

Madison shelf area to form the Madison karst plain (Sando, 

1988) (fig. 7). A sabkha, represented by the McKenzie 

Canyon Limestone in southwestern Montana and the uppermost part of the Mission Canyon Limestone in southeastern 

Idaho and western Wyoming, occupied the shore of the 

karst plain. A tremendous volume of quartz sand derived 

from the uplifted Transcontinental arch to the east was 

brought by rivers westward across the karst plain in northwestern Colorado to form the Humbug Formation in northeastern Utah and equivalent rocks in southwestern Wyoming and southeastern Idaho (Sandberg and others, 1982, 

p. 714). Meanwhile, open marine shelf carbonate deposition continued on the Leadville-Red wall shelf in southern 

Utah, northern Arizona. and southeastern Nevada. By this 

time, unfavorable environments excluded Ankhelasma from 

the northern part of the area. but it continued to live within 

a zone approximately 40 km wide at the shelf margin (figs. 

7 and 8) in southeastern Nevada and northeastern Arizona 

(table 1). The occurrence of the genus approximately 60 km 

landward from the shelf margin in extreme southeastern 

Nevada (locality 1) may be the result of incorrect location of 

the shelf margin due to poor control or to post-Laramide 

structural extension in this structurally complex area. 

In the United States, Ankhelasma became extinct by 

the end of the early middle Visean (Composite Zone 14). 

although seemingly favorable shelf carbonate environments 

continued into Composite Zone 15 on the LeadvilleRedwall shelf (columns 1-3 on fig. 5). No phylogenetic 

successors are known. 

Western Canada 

In Canada, Ankhelasma has been found in a much 

more restricted area than in the United States. It is known 

only from east-central British Columbia (figs. 1 and 3 ), 

where it occurs in 10 closely spaced outcrop sections within 

the overthrust belt of the Rocky Mountain front ranges (fig. 

9). Most of the occurrences are in a narrow belt of 

protected-shelf carbonates deposited slightly landward of 

the shelf margin of a carbonate platform (figs. 9-11) (see 

appendix C for complete descriptions of localities). The 

protected-shelf deposits extend northeastward from Jarvis 

Lakes in southeast Monkman Pass map area (NTS 931) into 

the Sukunka River region of the Pine Pass map area (NTS 

930). Numerous specimens have also been collected from 

middle-slope carbonates (fig. 11) deposited southwest of 

the shelf-margin grainstone belt in the northwestern part of 

the study area (figs. 9 and 10, localities 1 and 2). No 

specimens of Ankhelasma have been found elsewhere in the 

Canadian Cordillera or in the Interior platform to the east, 

although more than 100 coral collections from correlative 

strata have been examined. The belt of protected-shelf, 

shelf-margin, and slope carbonates extends northeastward 

from the study area into the subsurface (figs. 3 and 9), 

where very few coral collections are available. South of the 

study area, the genus has not been observed in the numerous 

occurrences of protected-shelf and shelf-margin facies 

examined, but in this area, most of these facies have not 

been thoroughly sampled. Also, few coral collections have 

been made from this stratigraphic interval from slopecarbonate rocks in areas other than the study area (fig. 3). 

Therefore, the apparent geographic restnctton of 

Ankhelasma in Canada is probably an artifact of sampling, 

but the possibility that it is related to undetermined environmental factors cannot be ruled out. 

Ankhelasma has the same age range (Composite 

Zones 12 to 14) in Canada as in the United States (fig. 12). 

Localities 5 and 9 have yielded specimens from the basal 

part of Composite Zone 12, but most occurrences are in 

Composite Zone 13 or in the lower part of Composite Zone 

14. The vertical distribution of these occurrences shows no 

obvious geographic pattern. Their zonal assignments are 

based on biostratigraphic data from associated foraminiferal 

faunas. The assignment of specimens from locality 2 was 

estimated from their stratigraphic position by correlation 

with nearby, well-dated sections. 

Ankhelasma lived on the protected shelf and middle 

slope of a poorly differentiated middle Visean carbonate 

platform that had a broad, sand-dominated shelf margin and 

low-gradient slope (fig. 11). The main lithofacies belts of 

the platform are incompletely preserved in the Turner 

Valley Formation, the lower part of the Mount Head 

Formation, and the Prophet Formation (fig. 10). The 

regional and local lithostratigraphy, lithofacies, and depositional environments of these formations have been discussed by Beauchamp and others (1986), Mamet and others 

(1986). and Richards and others (in press). A complete 

shelf-to-basin transition is preserved only in a series of 

sections (localities 1-3, fig. 9) in the northwestern part of 

the area. This transition reveals a westward progradation of 

the protected shelf, shelf margin, and slope. Elsewhere in 

the study area, protected-shelf deposits contammg 

Ankhelasma typicum are widely preserved, but shelf-margin 

deposits are preserved only at locality 10 (fig. 9), and slope 

lithofacies are absent. In east-central British Columbia, the 

protected-shelf deposits containing A. typicum (figs. 9 and 

10) formed near the seaward limit of the protected shelf and 

grade basinward (southwestward) into coeval shelf-margin 

and upper-slope facies. The protected-shelf deposits are 

mainly peloid- and pelletoid-bearing, mixed-skeletal grainstone and packstone deposited in shallow-subtidal (above 

storm wave base) environments (fig. 11). These deposits 

generally occur in the Turner Valley Formation and Baril(?) 

Member of the Mount Head Formation, but some of them 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 811 
EXPLANATION D Carboniferous deposits 

Limits of shelf margin deposits 

- Known Inferred 

••• Margin of Peace River embayment 

A A' 

o--o 

0 

Q2 

Line of cross section (see fig. 10) 

Control section 

Ankhelasma occurrence 

KILOMETERS 

Figure 9. Present nonpalinspastic facies distribution of Visean (Composite Zones 12 to 14) deposits, east-central 

British Columbia (see study area, fig. 3) and Ankhelasma occurrences in relation to shelf margin. 

are in the Wileman(?) Member of the Mount Head Formation (figs. 10 and 12). Toward the east, the broad belt of 

protected-shelf lithofacies commonly records deepening. 

Farther eastward, protected-shelf lithofacies indicate shallowing, and eventually grade into intertidal to supratidal 

812 Shorter Contributions to Paleontology and Stratigraphy 

carbonates and anhydrite deposited on the inner protected 

shelf and on a vast restricted shelf (figs. 10 and 11). 

The shelf-margin and upper slope facies are mainly 

bryozoan-pelmatozoan grainstone (fig. 11). In the study 

area, this belt of high-energy deposits, which has not been 
NW 

A 

345 

350 

355 

ENVIRONMENTS OF DEPOSITION 

c 

B 

B Basin (partly euxinic) 

C Slope 

D Upper slope and shelf margin (platform) 

E Upper slope and shallow shelf (ramp) 

F Shallow shelf (ramp) 

G Protected shelf and restricted shelf (platform) 

H Shelf margin and protected shelf (platform) 

I Shallow shelf and restricted shelf (ramp) 

J Inner shelf margin (platform) 

K Protected shelf (platform) 

L Restricted shelf 

M Slope to shallow shelf (ramp in part) 

~Limestone 

ErJ Dolostone 

1-<-<-< I Spiculite 

• • Chert 

_[___ Calcareous 

EXPLANATION 

I=-= I Shale and mudstone 

C=:J Shelf margin deposits 

Dill Hiatus 

Possible normal faults 

_____...... Unconformity, dashed 

Dolomitic where queried 

(fl Ankhelasma occurrences 

~ 0 

Cl 

z 

<( 

~ 

~ z 

0 

SE 2j 

a; 

~100L ~ 50 w 

~ 

0 20 

KILOMETERS 

Figure 10. Stratigraphic cross section A-A' showing Ankhelasma occurrences (appendix C, localities 1-10) and 

depositional environments (fig. 11) in Rundle Group and Besa River Formation, study area, east-central British Columbia. 

Line of cross section shown on figure 9. Adapted from Richards and others (in press). 

identified near Ankhelasma localities in the United States, is 

thin and relatively narrow compared to that of southwestern 

Alberta and southeastern British Columbia. In the latter 

region, the belt of shelf-margin grainstone is more than 30 

km wide. 

Toward the northwest, the shelf-margin and upperslope grainstone grades into finer grained middle-slope and 

upper-slope lithofacies that occur in the Prophet Formation 

(figs. 9 and 10, localities 1 and 2) and locally contain 

abundant Ankhelasma. The coral-bearing slope deposits are 

bioturbated, cherty, pelmatozoan-spicule packstone. Corals 

in these deposits are very well preserved but appear to have 

been reworked, because they are not in growth position. 

They are not, however, associated with either shallowwater fossils or abundant bryozoans and pelmatozoan ossicles, the principal allochems of upper-slope and shelfmargin deposits. We conclude that these corals lived on the 

middle slope and did not originate on the upper slope or 

shelf margin. These middle-slope dwellers (fig. 11) are 

represented by a new species of Ankhelasma (fig. 2 E. F) 

known from no other localities in Canada or the United 

States. The unique occurrence of this species in Composite 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 813 
OPEN MARINE 1 PROTECTED MARINE I RESTRICTED MARINE 

BASIN I MIDDLE SLOPE 

SHELF 

LOWER SLOPE I JuPPER SLOPE I MARGIN I PROTECTED SHELF I RESTRICTED SHELF 

I I I I SHOALS & I NERITIC I BEACHES ILAGOONSI SABKHAS 

Composite zone 14 

(Ankhelasma n. sp.) 

ISLANDS ENVIRONMENTS; TO 

LOCAL SHOALS TIDAL FLATS 

Composite zone 

12 to 14 Large-scale crossbeds and 

Tempestites, planar stratification 

Medium- to large-scale crossbeds 

and planar stratification 

small- to large-scale crossbeds, 

and rhythmic bedding Laminae, small-scale crossbeds, Laminae, small-scale crossbeds, 

Rhythmic bedding, 

Shale Spiculite and 

spiculitic limestone 

Lime packstone and wackestone; 

minor lime grainstone 

stromatolites, and 

Highly bioturbated lime 

wackestone and packstone 

Cryptalgal lime boundstone 

and highly bioturbated lime 

mudstone to packstone 

Dolomite mudstone to packstone 

and cryptalgal boundstone; 

evaporites and caliche 

EXPLANATION 

~ 

~ 

Lime grainstone; minor zz;z;zzz: 

lime packstone and II wackestone 

~Limestone 

~Dolostone 

~ Living zone of Ankhe/asma 

Anhydrite beds 

Anhydrite nodules 

Calcareous 

Dolomitic 

Shale or argillaceous 

Chert 

Sandy 

Silty 

@ 

a 

v 

:r;r 

w 

A' 

0 

:j:::j: 

© 

Pelmatozoan ossicles ..ru:'i Stromatolites, digitate to 

Corals hemispherical 

Brachiopods • Pelletoids 

Bryozoans 0 Peloids 

Foraminifers (!) Ooids 

Sponge spicules ,:5) Aggregate grains 

Calcispheres D Intraclasts 

Calcareous algae ~ Fenestral fabric 

Oncolites ..8' Terrestrial plant remains 

Figure 11. Generalized depositional model of Canadian Early Carboniferous carbonate platform (from Richards and 

others, in press). 

Zone 14 at these localities may represent a migration of the 

genus down the slope from its earlier habitat behind the 

shelf margin toward the end of its phylogenetic life span. 

The distribution of Ankhelasma suggests that the 

genus has considerable utility as a paleoenvironmental 

indicator. In east-central British Columbia, this readily 

identifiable and commonly abundant coral lived principally 

in neritic settings that were near or above storm wave base 

and were located on either side of the shelf-margin grainstone belt (fig. 11 ). All identified specimens of A. typicum 

came from deposits of the outer protected shelf. thereby 

suggesting that the species lived mainly on the outer 

protected shelf. A. n. sp. from localities 1 and 2 may be a 

slope indicator because it has been identified only from 

middle-slope deposits. Ankhelasma has not been observed 

in deep-water, shelf-margin, or intertidal deposits, and 

where it occurs in protected-shelf facies, these neritic 

deposits formed near the shelf margin. The fact that 

814 Shorter Contributions to Paleontology and Stratigraphy 

Ankhelasma has not been found east of the broad shelfmargin grainstone belt in Canada south of the study area 

may be related to the greater degree of restriction of the 

protected shelf in that area. 

INFERRED SHELF-MARGIN LOCATIONS 

Western United States 

In northwestern Montana, erosion during and following Mesozoic and Cenozoic uplift removed most of the 

record of Visean deposition (Sloss and Laird, 1945; Mudge 

and others, 1962; Haines, 1977), hence the location of the 

shelf margin is unknown. The occurrences of Ankhelasma 

at localities 12 and 13 provide a basis for estimating the 

shelf-margin location (fig. 6), by using the Ankhelasma 
:;r;.. 

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Figure 12. Temporal and stratigraphic distribution of Ankhelasma in east-central British Columbia. Coral symbols indicate positions of Ankhelasma at each 

locality. See figures 3 and 9 for geographic locations and appendix C for descriptions of localities. The positions of conodont biozone boundaries with respect 

to those of foraminifer, coral, and composite biozone boundaries differ slightly from those in the United States (see fig. 5). Foraminifer biozones are from Mamet 

and Skipp (1970). Conodont biozones are from Richards and others (in press) and Lane and others (1980). Coral biozones are from Sando and Bamber (1985). 

Composite biozones are from Sando (1985). 
Ma cz G' RATTLER GULCH SM1 MORRIS CREEK LITTLE G BLACKFOOT RIVER 

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355- 9 1- -t - - 1- --1 - - -+ - - 1- -l - 1-+ --+ - - F -=i - - --+ - - 1- --1 - - -+ - - 1- -J -~ ::JFigure 13. Chronometric lithofacies profiles from Ankhelasma localities 12 and 13 in westernmost Carboniferous outcrops 

in northwestern Montana to inferred shelf margin. Location of control points shown in figs. 6 and 7 and control points 

described in appendix D. Lost record indicated by shaded pattern. See figure 8 for explanation of other symbols. 

distribution model (see p. B4-Bll). These occurrences at 

localities 12 and 13 are in the lower half of Composite Zone 

13 (fig. 5). 

The Ankhelasma occurrence at Little Blackfoot River 

(locality 12, fig. 6) in profile G-G' (fig. 13) suggests a 

shelf-margin position no more than 50 km to the west of the 

Ankhelasma location, using the distribution model based on 

known distance from the shelf margin (table 1). However, 

outcrops of Visean rocks between locality 12 and Rattler 

Gulch, 65 km to the west, do not reveal a basinal facies in 

Composite Zone 13, suggesting a shelf-margin position 

B 16 Shorter Contributions to Paleontology and Stratigraphy 

west of Rattler Gulch. The present position of the inferred 

shelf margin in this profile (G~G'). based on westward 

projection of lithofacies trends, is approximately 75 km 

west of locality 12 (fig. 13). This anomaly is thought to be 

the result of post-Laramide structural extension along this 

profile, on the basis of recent recognition of structural 

extension in the thrust belt (W.J. Perry, oral commun., 

1987). 

The Ankhelasma occurrence at Hannan Gulch (locality 13, fig. 6) in profile H-H' (fig. 13) is compatible with 

the distribution model. Westward projection of lithofacies 
trends in this profile indicates a shelf-margin position 45 km 

west of the Ankhelasma location (fig. 13). 

Western Canada 

In the overthrust belt of east-central British Columbia, the protected-shelf occurrences of Ankhelasma are 

located in a narrow, northwest-trending outcrop belt subparallel to the depositional and structural strike of Visean 

rocks (figs. 3, 9, and 10). Visean shelf-margin deposits are 

preserved only in the northwestern and southeastern parts of 

the Carboniferous outcrop belt. Most Ankhelasma occurrences on the protected shelf lie east of an area of lost 

Visean record. The relative, present position of the shelfmargin deposits is known for only two of these occurrences 

(localities 9 and 10, figs. 9 and 10). The eastern limits of 

the shelf-margin deposits assigned to Composite Zones 12 

to 14 were projected into the area of lost record by means of 

lithofacies analyses based on unpublished field observations. The placement of these projected limits is supported 

by comparison with the occurrences of Ankhelasma shown 

on figure 9. All protected-shelf occurrences of the genus lie 

within 11 km of the known and projected eastern shelfmargin limits, well within the present-day width of the 

Ankhelasma belt established for the Western United States. 

The maximum present width of the main Ankhelasma 

belt on the protected shelf in Canada is less than the average 

width (about 22 km) of the Ankhelasma belt in the United 

States (table 1). This may be only an apparent difference 

resulting from different definitions of the shelf margin in the 

two areas. In Canada, the shelf margin is defined by a 

grainstone belt that is more than 10 km wide (fig. 9), 

whereas in the United States, the margin is defined by an 

arbitrary line separating shelf and off-shelf lithofacies (figs. 

6 and 7). Laramide thrusting and folding also may have 

reduced the widths of the Carboniferous facies belts more in 

Canada than in the United States. 

CONCLUSIONS 

(1) The distinctive, endemic rugose coral genus 

Ankhelasma Sando, 1961, occurs only in a narrow geographic belt in rocks of early and middle Visean age in the 

Western Interior region of North America. With very few 

exceptions, this Ankhelasma belt is located on the landward 

side of the Visean shelf margins. 

(2) Only two species have been recognized thus far in 

all the known occurrences of the genus. Ankhelasma typicum Sando, 1961, the more abundant species, lived exclusively in shallow, subtidal environments of the outer protected shelf within approximately 50 km of the shelf margin 

during the early and middle Visean. Toward the end of the 

phylogenetic life span of Ankhelasma, an undescribed new 

species lived on the middle slope of a middle Visean 

carbonate platform on the seaward side of the shelf margin 

in east-central British Columbia (Peace River embayment). 

(3) The model of Ankhelasma distribution, based on 

known occurrences, can be used to predict locations of 

Visean shelf margins in areas where the Visean depositional 

record was removed by erosion or obscured by later 

tectonism. This model may also be used to confirm or deny 

shelf-margin projections by lithofacies analyses into areas 

where lithofacies data are sparse or unavailable. 

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B.L., 1986, Lower Carboniferous lithostratigraphy and carbonate facies, upper Banff Formation and Rundle Group, 

east-central British Columbia, in Current Research, pt. A: 

Geological Survey of Canada Paper 86-1A, p. 627-644. 

Bierwagen, E.E., 1964, Geology of the Black Mountain area, 

Lewis and Clark and Powell Counties, Montana: Princeton, 

New Jersey, Princeton University, Ph.D. thesis, 120 p. 

Craig, L.C., and Connor, C.W., coordinators, 1979, Paleotectonic investigations of the Mississippian System in the United 

States: U.S. Geological Survey Professional Paper 1010, pt. 

III, 15 plates. 

Dockal, J.A., 1980, Petrology and sedimentary facies of Redwall 

Limestone (Mississippian) of Uinta Mountains, Utah and 

Colorado: Iowa City, Iowa, University of Iowa, Ph.D. thesis, 

423 p. 

Gordey. S.P., Abbott, J.G., Templeman-Kluit, D.J., and Gabrielse. H., 1987, "Antler" clastics in the Canadian Cordillera: 

Geology, v. 15, no. 2, p. 103-107. 

Gutschick. R.C., and Sandberg, C.A., 1983, Mississippian continental margins of the conterminous United States: Society 

of Economic Paleontologists and Mineralogists Special Publication 33, p. 79-96. 

Gutschick, R.C., Sandberg, C.A., and Sando, W.J., 1980, 

Mississippian shelf margin and carbonate platform from 

Montana to Nevada, in Fouch, T.D., and Magathan, E.R., 

eds., Paleozoic paleogeography of west-central United 

States: Rocky Mountain Section, Society of Economic Paleontologists and Mineralogists, West-Central United States 

Paleogeography Symposium 1 , p. 111-128. 

Haines, F .E., 1977, Lower Mississippian sedimentation in northwestern Montana: Rolla, Missouri, University of MissouriRolla, Ph.D. thesis, 116 p. 

Huh, O.K., 1967, The Mississippian System across the Wasatch 

line, east-central Idaho, extreme southwestern Montana: 

Montana Geological Society, Eighteenth Annual Field Conference Guidebook, p. 31-62. 

---1968, Mississippian stratigraphy and sedimentation across 

the Wasatch line. east-central Idaho and extreme southwestern Montana: State College, Pennsylvania, Pennsylvania 

State University, Ph.D. thesis, 175 p. 

Lane. H.R., Sandberg, C.A., and Ziegler, W .. 1980, Taxonomy 

and phylogeny of some Lower Carboniferous conodonts and 

preliminary standard post-Siphonodella zonation: Geologica 

et Palaeontologica. v. 14, p. 117-164. 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 817 
Langenheim, R.L., Jr., 1962, Nomenclature of the Late Mississippian White Pine Shale and associated rocks in Nevada: 

Illinois State Academy of Science Transactions, v. 55, no. 2, 

p. 133-145. 

---1963, Mississippian stratigraphy in southwestern Utah and 

adjacent parts of Nevada and Arizona: Intermountain Association of Petroleum Geologists, Twelfth Annual Field Conference Guidebook, p. 30-41. 

Mamet, B.L., and Skipp, Betty, 1970, Lower Carboniferous 

calcareous foraminifera; preliminary zonation and stratigraphic implications for the Mississippian of North America: 

International Congress of Carboniferous Stratigraphy and 

Geology, 6th, Sheffield, 1967, Comptes Rendus, v. 3, 

p. 1129-1146. 

Mamet, B.L., Bamber, E.W., and Macqueen, R.W., 1986, 

Microfacies of the Lower Carboniferous Banff Formation and 

Rundle Group, Monkman Pass map area, northeastern British 

Columbia: Geological Survey of Canada Bulletin 353, 93 p. 

Mudge, M.R., 1972, Pre-Quaternary rocks in the Sun River 

Canyon area, northwestern Montana: U.S. Geological Survey 

Professional Paper 663-A. 142 p. 

Mudge, M.R., Sando, W.J., and Dutro, J.T., Jr., 1962, Mississippian rocks of the Sun River Canyon area, Sawtooth Range, 

Montana: American Association of Petroleum Geologists 

Bulletin, v. 46, no. 11, p. 2003-2018. 

Nichols, K.M., 1986, Regional significance of lithologic correlation of Mississippian rocks at Pentagon Mountain and the 

Sawtooth Range, northwestern Montana: U.S. Geological 

Survey Open-File Report 86-39, 1 sheet. 

Nilsen, T. H., 1977, Paleogeography of Mississippian turbidites in 

south-central Idaho, in Stewart, J.H., Stevens, C.H .. and 

Frische, A.E., eds, Paleozoic paleogeography of the Western 

United States: Pacific Section, Society of Economic Paleontologists and Mineralogists, Pacific Coast Paleogeography 

Symposium 1, p. 175-299. 

Parker, J. W., and Roberts, J. W., 1963, Devonian and Mississippian stratigraphy of the central part of the Colorado Plateau: 

Four Corners Geological Society, Fourth Field Conference, 

Symposium on Shelf Carbonates of the Paradox Basin, p. 

31-60. 

Pierce, R.W., and Langenheim, R.L., Jr., 1974, Platform conodonts of the Monte Cristo Group, Mississippian, Arrow 

Canyon Range, Clark County, Nevada: Journal of Paleontology, v. 48, no. 1, p. 149-169. 

Poole, F.G., 1974, Flysch deposits of the Antler foreland basin, 

Western United States, in Dickinson, W.R., ed., Tectonics 

and sedimentation: Society of Economic Paleontologists and 

Mineralogists Special Publication 22, p. 58-82. 

Poole, F.G., and Sandberg, C.A., 1977, Mississippian paleogeography and tectonics of the Western United States, in 

Stewart, J .H., Stevens, C.H., and Fritsch, A.E., eds., 

Paleozoic paleogeography of the Western United States: 

Pacific Section, Society of Economic Paleontologists and 

Mineralogists, p. 67-85. 

Richards, B.C., Bamber, E.W., Higgins, A.C., and Utting, J., in 

press, Carboniferous, in Stott, D.F., and Aitken, J.D., eds., 

Sedimentary cover of the craton, chap. 4E (Stratigraphy): 

The geology of North America, Geological Survey of Canada, v. 6. 

818 Shorter Contributions to Paleontology and Stratigraphy 

Rose, P.R., 1976, Mississippian carbonate shelf margins, Western 

United States: U.S. Geological Survey Journal of Research, 

v. 4, no. 4, p. 449-466. 

Sandberg. C.A., and Gutschick, R.C., 1984, Distribution, microfauna, and source-rock potential of Mississippian Delle 

Phosphatic Member of Woodman Formation and equivalents, 

Utah and adjacent states, in Woodward, J., Meissner, F.F., 

and Clayton, J .L., eds., Hydrocarbon source rocks of the 

Greater Rocky Mountain region: Rocky Mountain Association of Geologists, p. 135-178. 

Sandberg, C.A., Gutschick, R.C., Johnson, J.G., Poole, F.G., 

and Sando, W.J., 1982, Middle Devonian to Late Mississippian geologic history of the Utah hingeline and overthrust belt 

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Cordilleran Thrust Belt, v. 2, p. 691-719. 

Sando, W.J., 1961, Morphology and ontogeny of Ankhelasma, a 

new Mississippian coral genus: Journal of Paleontology, v. 

35, no. 1, p. 65-81. 

---1976, Mississippian history of the northern Rocky Mountains region: U.S. Geological Survey Journal of Research, v. 

4, no. 3, p. 317-338. 

---1985, Revised Mississippian time scale, Western Interior 

region, conterminous United States: U.S. Geological Survey 

Bulletin 1605-A, p. A15-A26. 

---1988, Madison Limestone (Mississippian) paleokarst: A 

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eds., Paleokarst: New York, Springer-Verlag, p. 256-277. 

Sando, W.J., and Bamber, E.W., 1985, Coral zonation of the 

Mississippian System in the Western Interior province of 

North America: U.S. Geological Survey Professional Paper 

1334, 61 p. 

Sando, W.J., Bamber, E.W., and Armstrong, A.K., 1975, 

Endemism and similarity indices: Clues to the zoogeography 

of North American Mississippian corals: Geology, v. 3, no. 

11' p. 661--664. 

---1977, The zoogeography of North American Mississippian 

corals: Second International Symposium on Corals and Fossil 

Coral Reefs, Bureau de Recherches Geologiques et Minieres 

Memoire 89, p. 175-184. 

Sando, W.J .. and Dutro, J.T., Jr., 1981, Some stratigraphic 

sections of the Madison Group in the overthrust belt of 

western Wyoming and southeastern Idaho: U.S. Geological 

Survey Open-File Report 81-1354, 99 p. 

Sando, W.J., Dutro, J.T., Jr., and Gere, W.C., 1959, Brazer 

Dolomite (Mississippian), Randolph quadrangle, northeast 

Utah: American Association of Petroleum Geologists .Bulletin, v. 43, no. 12, p. 2741-2769. 

Sando, W.J., Sandberg, C.A., and Gutschick, R.C., 1981, 

Stratigraphic and economic significance of Mississippian 

sequence at North Georgetown Canyon, Idaho: American 

Association of Petroleum Geologists Bulletin, v. 65, no. 8, p. 

1433-1443. 

Sando, W.J., Sandberg, C.A., and Perry, W.J., Jr., 1985, 

Revision of Mississippian stratigraphy, Tendoy Mountains, 

southwest Montana: U.S. Geological Survey Bulletin 

1656-A, 10 p. 

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geochemistry, and mineral resource potential of the Eighteen-
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Idaho: U.S. Geological Survey Open-File Report 84-279, 55 

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Sloss, L.L., and Laird, W.M., 1945, Mississippian and Devonian 

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A.J., ed., Jurassic and Carboniferous of western Canada: 

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and granodiorite in Yukon: Evidence of arc-continent collision: Geological Survey of Canada Paper 79-14, 27 p. 

APPENDIX A. ANKHELASMA LOCALITIES IN 

THE UNITED STATES 

1. Potosi Mine 

Location: CNl/2 SWl/4 NEl/2 sec. 12, T. 23 S., R. 57 E., 

Shenandoah Peak quadrangle (15 min), Goodsprings district, Clark County, Nevada. 

Stratigraphic position: Y ellowpine Member of Monte 

Cristo Limestone, 0-1.2 m (0-4 ft) 

above base. 

Collections: • USGS 27968-PC, 0.9-1.2 m (3-4ft) above 

base: Approximately 150 silicified specimens of A. typicum Sando etched from 

limestone. 

• Sandberg Sample P0-3, lower 0.09 m (0.3 

ft): Two silicified specimens of A. sp. indet. 

etched from limestone. 

Lithology: Thick-bedded, fine- to medium-grained crinoidal limestone. Collected sample is dark, crinoidal packstone. 

Age: Associated fossils (USGS 27968-PC) are Canadiphyllum? sp., Syringopora sp., and Foraminifer 

Zone 12 microfossils (table AI). The occurrence is 

regarded as high in Composite Zone 14 because the 

underlying Arrowhead Member contains Foraminifer Zone 12 microfossils (table AI) (USGS 

27967-PC), and overlying beds in the Yellowpine 

Member yielded Foraminifer Zone 12/13 microfossils (table AI) (USGS 27969-PC). 

2. Tungsten Gap (see Pierce and Langenheim, 1974, for 

published stratigraphic section. 

Location: CNl/2 sec. 10, T. 15 S., R. 64 E., Arrow 

Canyon quadrangle (15 min), Arrow Canyon 

Range, Clark County, Nevada. 

Stratigraphic position: Y ellowpine Member of Monte 

Cristo Limestone, 1.5-7.6 m 

(5-25 ft) above base. 

Collections: • USGS 27974-PC, 7.6 m (25ft) above base: 

Approximately 40 calcareous specimens of 

A. typicum Sando in limestone. 

• USGS 27841-PC, lower 6.1 m (20 ft): 

Approximately 20 calcareous specimens of 

A. typicum Sando in limestone. 

• USGS 27842-PC, 1.5-2.4 m (5-8 ft) above 

base: Approximately 100 calcareous specimens of A. typicum Sando in limestone. 

Lithology: Thick-bedded, dark, fine- to medium-grained 

crinoidal limestone. Collected samples are 

dark, medium-grained crinoidal grainstone. 

Age: Foraminifer control is lacking in this section. The 

occurrence of Siphonodendron sp., Vesiculophyllum 

sp. , Amplexizaphrentis sp. , and Syringopora sp. 

suggests Coral Zone IliA or B. Conodont evidence 

suggests that the Ankhelasma occurrence is high in 

Composite Zone 14, similar to the occurrence at 

Potosi Mine (C.A. Sandberg, oral commun., 1986). 

3. Virgin River Gorge (see Steed, 1980, for general geology 

of this locality). 

Location: Sees. 20 and 30, T. 41 N., R. 14 W., Littlefield 

quadrangle (15 min), Mohave County, Arizona. 

Stratigraphic position: Lowermost part of Y ellowpine 

Member of Monte Cristo Limestone. 

Age: Abundant specimens of Ankhelasma sp. undet. were 

identified in the field by C.A. Sandberg (oral commun., 1986). No fossils were collected, but this 

occurrence is presumably the same stratigraphic 

level and age (Composite Zone 14) as occurrences at 

Potosi Mine and Tungsten Gap. 

4. Samak (see Dockal, 1980, for additional data). 

Location: Sl/2 NEl/4 NEl/4 sec. 25, T. 2 S., R. 6 E., 

Woodland quadrangle (7 .5 min), Uinta Mountains, Summit County, Utah. 

Stratigraphic position: Brazer Dolomite, 1.5 m (5 ft) 

below top of Mission Canyon 

equivalent (member 2 of the 

Brazer). 

Collection: • USGS 27065-PC: One silicified specimen of 

A. cf. A. typicum Sando etched from limestone. 

Lithology: Medium-bedded, dark, fine- to mediumgrained crinoidallimestone. Collected sample 

is partly dolomitized crinoidal packstone. 

Age: Ankhelasma occurs here with Siphonodendron oculinum Sando, Sychnoelasma sp., Vesiculophyllum 

sp., Lophophyllum? sp., Amplexizaphrentis sp., and 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 819 
Table Al. Foraminifers and algae in samples from the United States cited in appendix A 

[All samples are registered in U.S. Geological Survey Upper Paleozoic Catalog, except for BSH-2A, which is in the catalog of C.A. Sandberg. 

Identifications of fossils by B.L. Mamet] 

r}, 

~ 

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0 > ..::.t. ~ 

~ (1) 

c <il ..::.t. 0 (1) 

~ 0 u (1) >- <il 

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~ <il "'0 u >- u 

0 u (1) ..::.t. (1) c <il 

Taxa E u (1) <il as ·;:;; :::r:: <il <il $9 a. ..c u 0 E c tJl (1) Cfl (1) 

0 -~ E c >- (1) bJ) <il a) "B ..c 0... r= L.I.J ::::> :::r:: Cfl co o::l :.::::i 

<( 

0'1 co I'-... ~ \.!:) ~ \.!:) N ~ I'-... ~ 1.1"') 1.1"') 0'1 M \.!:) \.!:) \.!:) I'-... M I'-... 0'1 ~ ~ I'-... :::r:: 0 0 0 co 0'1 0'1 0'1 0 0'1 0 co ~ \.!:) M M ;! I'-... I'-... I'-... I'-... \.!:) co I'-... 0 0 0 Cfl co 0'1 0'1 

N N N N ~ ~ ~ N N N o::l N N N N 

Atractyliopsis sp. X 

Brunsia sp. X 

Calcisphaera laevis Williamson X X X X X 

C. pachysphaerica (Pronina) X X X X X X X X X 

C. sp. X X X X X 

Dainella cf. D. anivikensis Mamet X 

D. sp. X 

Earlandia clavicula (Howchin) X 

E. vulgaris (Rauzer-Chemoussova and Reidinger) X X X X X X X X X X 

E. sp. X X X X 

Eblanaia sp. X X 

Endothyra sp. X X X X X X X X X 

cf. Endothyranopsis? sp. X 

Eoendothyranopsis hinduensis (Skipp) X X X 

E. scitula (Toomey) X 

E. spiroides (Zeller) X X X 

E. spiroides spiroides (Zeller) X X 

E. of the group E. spiroides (Zeller) X X X X X 

E. sp. X X 

Eoforschia moelleri (Malakhova in Dain) X 

E. sp. X X X X X X 

Eogloboendothyra sp. X X ? X X 

Eoparastafella ova/is V dovenko X X 

Girvanella sp. X 

Globoendothyra bridgensis (Skipp) X 

G. of the group G. baileyi (Hall) X X X X X X 

G. of the group G. tomiliensis (Grazdilova in Lebedeva) X X 

G. sp. X X X X X X 

G.? trachida (Zeller) X 

Issinella devonica Reidinger X 

I. sp. X 

Koninckopora inflata (de Koninck) X 

K. sp. X 

Latiendothyra sp. X X X X 

Mametella sp. X X X 

Orthriosiplwn sp. X X 

Orthriosiphonoides sp. X X 

Ortonella sp. X X 

Paleoberesella lahuseni (von Moller) X 

P. sp. X X 

Parathurammina sp. X X X 

Pohlia henbesti (Skipp. Holcomb, and Gutschick) X 

Priscella sp. X X X X X X X X X X X X X 

Pseudoammodiscus sp. X X 

Septabrunsiina sp. X 

S. sp. X X X X 

cf. Skippella? sp. X X 

cf. Spinoendothyra? sp. X 

Stacheinae X 

Stacheoides sp. ? X 

Tetrataxis sp. X X X X 

820 Shorter Contributions to Paleontology and Stratigraphy 
Syringopora morpho group C (USGS 27065-PC), 

which are indicative of Coral Zone IliA (near base). 

Conodonts from this stratigraphic level represent 

either the Scaliognathus anchoralis-Doliognathus 

latus Zone or the Gnathodus texanus Zone (C.A. 

Sandberg, oral commun., 1978). These fossils suggest a zonal position at or near the base of Composite Zone 12. 

5. Trail Hollow (see Dockal, 1980, for additional data). 

Location: NWI/4 sec. 33, T. 3 S., R. 9 W., Iron Mountain 

quadrangle (7 .5 min), Uinta Mountains, 

Wasatch County, Utah. 

Stratigraphic position: Brazer Dolomite, 1.5-7.6 m (5-25 

ft) below top of Mission Canyon 

equivalent (member 2 of the 

Brazer). 

Collection: • USGS 27074-PC: Approximately 100 calcareous specimens of A. typicwn Sando in 

limestone. 

Lithology: Thin- to thick-bedded, weakly laminated, 

coarse-grained bioclastic limestone. Collected 

sample is dark, partly dolomitized coral packstone. 

Age: This sample contains the same assemblage of corals 

and conodonts as USGS 27065-PC at Samak. It also 

contains foraminifers that have a possible range of 

Foraminifer Zone 10 to 12 (table A1). A zonal range 

at or near the base of Composite Zone 12 is 

indicated. 

6. Crawford Mountains (see Sando and others, 1959, and 

Sando, 1961, for additional data). All specimens belong to 

Ankhelasma typiczmz Sando and are from the Randolph 

quadrangle (15 min), Rich County, Utah. 

A. Unnamed locality 

Location: NWI/4 NWI/4 sec. 29, T. 11 N., R. 8 E. 

Stratigraphic position: Brazer Dolomite, upper 

member (member 3), exact 

position unknown. 

Collection: • USGS 486-PC: Three specimens preserved as molds and casts in chert. 

Lithology: Collected sample is cherty, dark, finegrained calcitic dolomite. 

Age: The sample contains nondiagnostic brachiopods and corals. It is dated as middle Composite Zone 12 on the basis of similarity of 

its stratigraphic position to collections from 

nearby localities that have been dated by 

diagnostic fossils. 

B. Brazer Canyon (type section of Brazer Dolomite) 

Location: SE1

h NWI/4 sec. 20, T. 11 N., R. 8 E. 

Stratigraphic position: Brazer Dolomite, 44.5-

50.6 m (146-166 ft) above 

base of upper member. 

Collections: • USGS 16906-PC, 44.5 m (146 ft) 

above base: Two poorly preserved 

calcitic and dolomitic specimens in 

dolomite. 

• USGS 16907-PC, 48.2 m (158 ft) 

above base: Two poorly preserved 

calcitic and dolomitic specimens in 

dolomite. 

• USGS 16908-PC, float from 41.2-

50.6 m (135-166 ft) above base: 

Eleven poorly preserved calcitic and 

dolomitic specimens in dolomite. 

Age: These samples contain Zaphriphyllum sp., 

Canadiphyllum sp., and Vesiculophyllum? 

sp., which suggest Coral Zone IliA. A zonal 

position near the middle of Composite Zone 

12 is suggested by proximity to Coral Zone 

II corals in the underlying Mission Canyon 

equivalent (member 2 of the Brazer). No 

conodonts or foraminifers were found. 

C. Emma Canyon 

Location: C sec. 17, T. 11 N., R. 8 E. 

Stratigraphic position: Brazer Dolomite, 44.2-

56.4 m (145-185 ft) above 

base of upper member 

(member 3). 

Collections: • USGS 16936-PC, 48.2 m (156 ft) 

above base: Approximately 30 specimens preserved as molds and casts 

in chert. 

• USGS 16938-PC, 56.4 m (185 ft) 

above base: Six poorly preserved 

calcitic and dolomitic specimens in 

dolomite. 

• USGS 16939-PC, 44.2 m (145 ft) 

above base: Three poorly preserved 

calcitic and dolomitic specimens in 

dolomite. 

Lithology: Same as locality 6B; chert preserves 

pelletal packstone texture. 

Age: The interval containing Ankhelasma at this 

locality is approximately the same as that at 

locality 6B, which has been dated as middle 

Composite Zone 12. USGS 16936-PC at 

Emma Canyon contains microfossils of 

Foraminifer Zone 10 or 11 (table A1), which 

confirms the Composite Zone 12 determination. 

D. Rex Peak 

Location: N1

h sec. 31, T. 11 N., R. 8 E. 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 821 
Stratigraphic position: Brazer Dolomite, 37.5-

40.5 m (123-133 ft) above 

base of upper member 

(member 3). 

Collections: • USGS 17717-PC, exact position 

unknown: Several hundred poorly 

preserved silicified specimens 

etched from dolomite. 

• USGS 17722-PC, 37.5-40.5 m 

(123-133 ft) above base: 285 wellpreserved silicified specimens and 

several hundred poorly preserved 

ones etched from dolomite. 

Lithology: Same as locality 6B. 

Age: Same as locality 6B. 

E. Unnamed Crawford Mountains 

Location: NWl/4 NWl/4 sec. 6, T. 10 N., R. 8 E. 

Stratigraphic position: Brazer Dolomite, upper 

member (member 3), exact 

position unknown. 

Collection: • USGS 18074-PC, exact position 

unknown: Approximately five poorly 

preserved calcitic and dolomitic specimens in dolomite. 

Lithology: Same as locality 6B. 

Age: Same as locality 6B. USGS 18074-PC contains 

microfossils of Foraminifer Zone 10 or 11 (table 

A1), which confirms the Composite Zone 12 determination for Ankhelasma at this locality. 

7. Haystack Peak (see Sando and Dutro, 1981, for description of stratigraphic section). 

Location: NWl/4 NEl/4 sec. 27, T. 34 N., R. 117 W., 

Bedford quadrangle (7 .5 min), Salt River 

Range, Lincoln County, Wyoming. 

Stratigraphic position: Mission Canyon Limestone, 

94.5-97.5 m (310-320 ft) below 

top (unit 49 of Sando and Dutro, 

1981, p. 12). 

Collection: • USGS 17900-PC: One partly silicified calcitic specimen in limestone and two silicified 

specimens etched from limestone, all identified as A. cf. A. typicum Sando. 

Lithology: Thin- to medium-bedded, medium- to very 

coarse grained crinoidal bioclastic limestone. 

Collected sample is dark crinoidal packstone. 

Age: This occurrence is well documented with corals of 

Zone IliA (Siphonodendron oculinum Sando, Zaphriphyllum sp., Amplexizaphrentis sp., Vesiculophyllum sp., Sychnoelasma sp., Syringopora morphogroups B and C, Pleurosiphonella morphogroup A) 

that occur in the same bed (USGS 17900-PC) and 

above (USGS 1790 1-PC) and below (USGS 

17899-PC) it. Foraminifer Zone 9/10 microfossils 

occur below the collection (table Al) (USGS 

822 Shorter Contributions to Paleontology and Stratigraphy 

17896-PC). A zonal position near the middle of 

Composite Zone 12 is indicated for Ankhelasma 

here. 

8. Sheep Creek (see Sando and Dutro, 1981 , for description 

of stratigraphic section). 

Location: El/2 sec. 28, T. 1 N., R. 45 E., Irwin quadrangle (30 min), Snake River Range, Bonneville 

County, Idaho. 

Stratigraphic position: Mission Canyon Limestone, 

93-96 m (305-315 ft) below top 

(unit 56 of Sando and Dutro, 1981, 

p. 86). 

Collection: • USGS 20122-PC: One calcitic specimen of 

A. cf. A. typicum Sando in limestone. 

Lithology: Medium- to thin-bedded, dark, predominantly 

fine-grained limestone. Collected sample is 

dark, crinoidal, foraminiferal packstone. 

Age: This occurrence is well documented with corals of 

Zone IliA (Siphonodendron oculinum Sando, Zaphriphyllum sp., Amplexizaphrentis sp., Vesiculophyllum sp. , Syringopora morpho groups B and C). The 

corals occur with microfossils of Foraminifer Zones 

10-11 (table A 1) (USGS 20 122-PC) and occur 

below microfossils of Foraminifer Zone 11 (table 

A1) (USGS 20121-PC) and above microfossils of 

Foraminifer Zone 10(?) (table A1) (USGS 

20117-PC). A zonal position in the upper half of 

Composite Zone 12 is indicated for Ankhelasma 

here. 

9. Chamberlain Creek (see Skipp and others, 1984, pl. 1, 

for geologic map of the area). 

Location: SEl/4 sec. 20, T. 14 N., R. 29 E., Morrison 

Lake quadrangle (15 min), Beaverhead Mountains, Lemhi County, Idaho. 

Stratigraphic position: Debris flow in Middle Canyon 

Formation, exact position unknown. 

Collection: • USGS 29260-PC: One calcitic specimen of 

A. cf. A. typicum Sando in limestone. 

Lithology: Collected sample is dark, silty and argillaceous, phosphatic, coarse-grained crinoidal 

grainstone. 

Age: Other megafossils collected from the locality (USGS 

29584-PC) include indeterminate hom corals, 

euomphalacean gastropods, a spiriferoid brachiopod, and an orthoceracone cephalopod, none of 

which is diagnostic for age determination. Matrix 

from USGS 29584-PC yielded zonally indeterminate conodonts Bispathodus utahensis and Polygnathus communis communis, which have a range 

from Osagean to middle Meramecian (late Tournaisian to middle Visean) (C.A. Sandberg, written 

commun., 1985). The deposit is interpreted as a 

debris flow derived from shallow-water-shelf sediments of Composite Zone 12 age (Mission Canyon 
Limestone) and redeposited in a deep basin represented by the Middle Canyon Formation. Dating is 

based on the age of in situ occurrence at Big Sheep 

Creek (locality 10). 

10. Big Sheep Creek 

Location: SWI/4 NEI/4 sec. 22, T. 14 S., R. 10 W., 

Gallagher Gulch quadrangle (7 .5 min), Tendoy 

Mountains, Beaverhead County, Montana. 

Stratigraphic position: Mission Canyon Limestone, upper 

member, approximately 6. 7 m (22 

ft) above base. 

Collection: • USGS 28605-PC: Six calcitic specimens of 

A. cf. A. typicum Sando in limestone. 

Lithology: Collected sample is dark, partly dolomitized 

crinoidal packstone. 

Age: Corals of Zone IliA (Vesiculophyllum sp., Siphonodendron oculinum Sando, and Syringopora sp.) 

occur immediately above the bed containing 

Ankhelasma. Microfossils of Foraminifer Zone 

10-11 (table A1) (Sandberg Sample BSH-2A) occur 

at the same level as the collected sample. A zonal 

position near the base of Composite Zone 12 is 

indicated for Ankhelasma here. 

11. Bell Canyon (see Sando and others, 1985, for section 

description). 

Location: NWI/4 NEl/4 SW1/4 sec. 17, T. 11 S., R. 10 W., 

Red Rock and Kidd quadrangles (7 .5 min), 

Tendoy Mountains, Beaverhead County, Montana. 

Stratigraphic position: Mission Canyon Limestone, near 

top of lower(?) member to 26 m 

(85.3 ft) below top of upper member. 

Collections: • USGS 29305-PC, 26m (85.3 ft) below top 

of upper member: Three calcitic specimens 

of A. cf. A. typicum Sando in limestone. 

• USGS 28604-PC, structurally complex outcrops seemingly near top of lower member: 

Five calcitic specimens of A. cf. A. typicum 

Sando in limestone. 

Lithology: Collected sample USGS 29305-PC is dark, 

partly dolomitized crinoidal grainstone. Collected sample USGS 28604-PC is light, 

sheared and veined, crinoidal packstone. 

Age: The lowest Ankhelasma found in this sequence 

(USGS 28604-PC) is from structurally complex 

outcrops that seem to belong to the uppermost part 

of the lower member of the Mission Canyon Limestone. This sample contains zonally undiagnostic 

corals (Vesiculophyllum sp., Ample.Yizaphrentis sp.) 

and microfossils of Foraminifer Zone 11 or 12 (table 

Al). 

A higher occurrence near the top of the upper 

member of the Mission Canyon Limestone (USGS 

29305-PC) is well located stratigraphically and is 

well documented by corals of Zone IliA (Siphonodendron oculinum Sando) both above it (USGS 

29306-PC) and below it (USGS 19304-PC). 

Ankhelasma here occurs with microfossils of Foraminifer Zone 11 or 12 (table AI) (USGS 29305-PC), 

and the occurrence is not far below Foraminifer 

Zone 12 microfossils (USGS 29309-PC) at the top 

of the upper member. The total range of Ankhelasma 

at this locality would seem to be from a level low in 

Composite Zone 13 to about the middle of that 

composite zone. 

12. Little Blackfoot River (Hope Creek) (see Bierwagen, 

1964, for description of the locality). 

Location: NWI/4 SWL/4 sec. 29, T. 11 N., R. 6 W., Helena 

quadrangle (15 min), Lewis and Clark County, 

Montana. 

Stratigraphic position: Mission Canyon Limestone, near 

top. 

Collection: • USGS 21483-PC, near top of Mission Canyon Limestone: One calcitic specimen of A. 

cf. A. typicum Sando in limestone. 

Lithology: Collected sample is dark, medium-grained, 

crinoidal oolitic grainstone. 

Age: Approximate stratigraphic position of this occurrence was established by reconnaissance of the 

outcrop area by Sando. The collected sample contains microfossils of Foraminifer Zone 11 (table 

A1), which indicates a position in Composite Zone 

13. 

13. Hannan Gulch (see Mudge and others, 1962, and 

Mudge, 1972, for description of stratigraphic section). 

Location: Sec. 35, T. 22 N., R. 9 W., Sawtooth Ridge 

quadrangle (7 .5 min), Sawtooth Range, Teton 

County, Montana. 

Stratigraphic position: Sun River Member of Castle Reef 

Dolomite, 48.8 m (160 ft) above 

base of member. 

Collections: • USGS 18005-PC: One dolomitic specimen 

(five transverse thin sections) of A. cf. A. 

typicum Sando in dolomite. 

• USGS 19542-PC: Five dolomitic specimens 

of A. cf. A. typicwn Sando in dolomite. 

Lithology: Collected samples are light, medium- to 

coarse-grained dolomitized crinoidal grainstone or packstone. 

Age: Ankhelasma occurs with Zaphriphyllum sp., which 

suggests Coral Zone IliA for the occurrence. 

Nichols (1986) reported Gnathodus texanus Zone 

conodonts from the same beds. The zonal level is 

probably the lower half of Composite Zone 13. 

Ankhe/asma-lndex to Visean Shelf Margin, Western Interior of North America 823 
APPENDIX B. CONTROL POINTS FOR 

CHRONOMETRIC LITHOFACIES PROFILES 

ACROSS KNOWN VISEAN SHELF MARGIN IN 

THE UNITED STATES (FIG. 8) 

[Interpretations of the stratigraphy by the writers may differ 

from published references] 

Profile A-A' 

Kane Springs Wash: T. 11 S., R. 64 E., Lincoln 

County, Nevada. Graphic section by Langenheim 

(1962, fig. 2, and 1963, fig. 2). Ages determined by 

physical correlation to Alamo section in T. 6 S., R. 

60 E. (Poole and Sandberg, 1977, fig. 2b, loc. 20). 

Tungsten Gap: Sees. 11 and 12, T. 14 S., R. 64 E., 

Clark County, Nevada. Unpublished section measured by Sandberg and Sando. Ages determined by 

conodonts and corals. 

Profile B-B' 

Dog Valley Peak: Sec. 17, T. 25 S., R. 6 W., Millard 

County, Utah. Unpublished section measured by 

Sandberg, Gutschick, and Sando. Part of section 

described by Sandberg and Gutschick (1984, fig. 

10). Ages determined by foraminifers, conodonts, 

and corals. 

Texaco No. 1 Thousand Lake Mountain well: Sec. 11, 

T. 28 S., R. 4E., Wayne County, Utah. Well log by 

Parker and Roberts (1963, fig. 14). Ages determined by physical correlation to Beaverdam Mountains in sec. 35, T. 42 S., R. 18 W., Washington 

County (Langenheim, 1963, fig. 1). 

Profile C-C' 

City Creek Canyon: Sec. 5, T. 1 N., R. 2 E., Summit 

County, Utah. Unpublished section measured by 

Gutschick. Ages determined by corals. 

Samak: Sec. 25, T. 2 S., R. 6 E., Summit County, 

Utah. Section described by Dockal (1980, p. 

263-280). Ages determined by corals, foraminifers, 

and conodonts. 

Profile D-D' 

Old Laketown Canyon: Sec. 32, T. 32 N., R. 6 E., 

Rich County, Utah. Section described by Sando and 

others (1959, p. 2762-2763, fig. 5) and reinterpreted by Sando and others (1981, fig. 6, col. 3). 

Ages determined by corals, conodonts, and foraminifers. 

Brazer Canyon: Sec. 20, T. 11 N., R. 8 E., Rich 

County, Utah. Section described by Sando and 

others (1959, p. 2751-2754, fig. 5) and reinterpreted by Sando and others (1981, fig. 6, col. 5). 

Ages determined by corals, conodonts, and foraminifers. 

Profile E-E' 

Wolverine Canyon: Sees. 1, 2, 10, and 11, T. 2 S., R. 

38 E., Bingham County, Idaho. Unpublished sec824 Shorter Contributions to Paleontology and Stratigraphy 

tion measured by Sandberg and Sando. Ages determined by corals and foraminifers. 

Fall Creek: Sec. 8, T. 1 N., R. 43 E., Bonneville 

County, Idaho. Locality studied by Sando and 

Sandberg. Ages determined by corals. 

Sheep Creek: El/2 sec. 28, T. 1 N., R. 45 E., 

Bonneville County, Idaho. Section described by 

Sando and Dutro ( 1981). Ages determined by corals 

and foraminifers. 

Profile F -F' 

Chamberlain Creek: Sec. 20, T. 14 N., R. 29 E., 

Lemhi County, Idaho. Locality mapped by Skipp 

and others ( 1984). Ages determined by conodonts 

and by physical correlation to Copper Mountain 

section in sees. 25 and 26, T. 10 N., R. 30 E., Clark 

County (Huh, 1967, fig. 3, and 1968, section log). 

Big Sheep Creek: Sec. 36, T. 14 S., R. 10 W., 

Beaverhead County, Montana. Unpublished section 

measured by Sandberg and Sando. Ages determined 

by corals and foraminifers. 

APPENDIX C. ANKHELASMA LOCALITIES IN 

EAST-CENTRAL BRITISH COLUMBIA, CANADA 

1. Mountain Creek 

Location: Lat 55°23'30" N., long 122°26'00" W.; approximately 2.4 km (1.5 mi) east of Mountain 

Creek, Pine Pass 1:250,000-scale map sheet 

(NTS 930). 

Stratigraphic position: Prophet Formation, 129.8 -150m 

(426--492 ft) below top, upper part 

of member B. 

Collections: • GSC loc. C4562, 149.3-150 m (490--492 ft) 

below top of Prophet Formation: Approximately 250 silicified specimens of A. n. sp. 

• GSC loc. C4563, 135.3-141.4 m (444--464 

ft) below top of Prophet Formation: One 

immature, silicified specimen of A. typicum? Sando. 

• GSC loc. C4564, 129.8 m (426 ft) below 

top of Prophet Formation: Two silicified 

specimens of A. sp. indet. 

Lithology: Cherty, peloid-bearing, partly dolomitic, spicular, mixed-skeletal packstone and subordinate 

wackestone and grainstone. Lower part of unit 

contains dolomitic spiculite. 

Collected samples: • GSC loc. C4562, slightly cherty 

and argillaceous, pelmatozoanspicule packstone having corals, 

brachiopods, and bryozoans. 

• GSC loc. C4563, sparsely fossiliferous, finely crystalline dolostone having brachiopods and corals. 
• GSC loc. C4564, cherty, peloidspicule lime packstone having corals, pelmatozoan ossicles, and brachiopods. 

Age: All Ankhelasnza occurrences at this locality are 

assigned to Composite Zone 14. Associated corals 

(GSC loc. C4562) are Amplexizaphrentis sp. and 

Lophophyllum? sp., which are zonally nondiagnostic, but microfossils from 19.3 m (63 ft) above 

Ankhelasma belong to Foraminifer Zone 12 (GSC 

loc. C69462), and those from 11.3 m (37 ft) below 

Ankhelasma are tentatively assigned to Foraminifer 

Zone 11 or 12 (GSC loc. C69453) (table C1). 

2. South Mountain Creek 

Location: Lat 55°22'00" N., long 122°23'15" W.; approximately 3.2 km (2 mi) east of Mountain Creek, 

Pine Pass 1:250,000-scale map sheet (NTS 

930). 

Stratigraphic position: Prophet Formation, 134.1 m (440 

ft) below top, uppermost part of 

member B. 

Collection: • GSC loc. C110910: Twenty-five silicified 

specimens of A. n. sp. 

Lithology: Cherty, spicular limestone similar to the rocks 

described in the Mountain Creek section 

(locality 1). No matrix was preserved in the 

collected sample. 

Age: No associated fossils were found at South Mountain 

Creek, but in the nearby Mountain Creek section 

(fig. 12, locality 1 ), microfossils from approximately the same stratigraphic level belong to Foraminifer Zone 12. Hence, the South Mountain Creek 

occurrence of Ankhelasma is regarded as Composite 

Zone 14. 

3. Sukunka River 

Location: Lat 55°01'20" N., long 121 °38'25" W.; approximately 6.4 km (4 mi) east of the upper Sukunka River, Dawson Creek 1 :250,000-scale map 

sheet (NTS 93P). 

Stratigraphic position: Turner Valley Formation, 7.3 m 

(24 ft) below top. 

Collection: • GSC loc. C4629: Two silicified specimens of 

A. sp. indet. 

Lithology: Packstone and wackestone rich in algae and 

subordinate echinoderm-bryozoan grainstone 

in upper part of unit. Main bioclasts are 

calcareous algae, foraminifers, pelmatozoan 

ossicles, and ostracodes. Collected sample is 

peloid-pelmatozoan grainstone having calcareous algae, pelletoids, calcispheres, and foraminifers. 

Age: Associated corals are Zaphriphyllum cf. Z. disseptum Sutherland, which suggests the upper part of 

Coral Zone IliA. Microfossils of Foraminifer Zone 

11 (GSC loc. C69613) (table C1) occur 11.3 m (37 

ft) below Ankhelasma. The occurrence of 

Ankhelasma here is regarded as Composite Zone 13. 

4. Hook Creek 

Location: Lat 54°48'40" N., long 121°19'00" W.; approximately 1.6 km (1 mi) northeast of Hook Lake, 

Monkman Pass 1:250,000-scale map sheet 

(NTS 931). 

Stratigraphic position: Turner Valley Formation, 43 m 

(141 ft) above base. 

Collection: • GSC loc. C7316: Four silicified, immature 

specimens of A. typicum? Sando. 

Lithology: Cherty, peloid- and pelletoid-bearing, mixedskeletal lime grainstone and packstone and 

subordinate lime wackestone and dolostone. 

Main bioclasts are calcareous algae, foraminifers, and pelmatozoan ossicles. Collected 

sample is slightly cherty, pelletoid-foraminifer-pelmatozoan packstone having corals, brachiopods, and peloids. 

Age: Associated corals are Zaphriphyllum sp., Amplexizaphrentis sp., and Ek:vasophyllum cf. E. ineZ inatum Parks, suggestive of Coral Zone IliA or B. 

Microfossils from the same stratigraphic level are 

tentatively assigned to Foraminifer Zone 11 (GSC 

loc. C39132) (Mamet and others, 1986, p. 43). 

Microfossils 11.9 m (39ft) above Ankhelasma (GSC 

loc. C39134) are definitely assigned to Foraminifer 

Zone 11, and those 25 m (82 ft) below Ankhelasma 

(GSC loc. C39128) belong to the basal part of 

Foraminifer Zone 10 (Mamet and others, 1986, p. 

43). Hence, we regard the occurrence of 

Ankhelasma at this locality as in the lower part of 

Composite Zone 13. 

5. East Fellers Creek 

Location: Lat 54°42'50" N., long 120°54'30" W.; approximately 6.4 km (4 mi) northwest of Bone 

Mountain, Monkman Pass 1:250,000-scale map 

sheet (NTS 931). 

Stratigraphic position: Turner Valley Formation, 3-14m 

(10-46 ft) above base. 

Collections: • GSC loc. C7347, 3 m (10 ft) above base of 

Turner Valley Formation: Six silicified 

specimens of A. typicum Sando. 

• GSC loc. C7350, 14m (46ft) above base of 

Turner Valley Formation: Two silicified, 

immature specimens of A. sp. indet. 

• GSC loc. C7351, 13.9 m (45.5 ft) above 

base of Turner Valley Formation: Two silicified, immature specimens of A. sp. indet. 

Lithology: Cherty, skeletal dolomite grainstone and fossiliferous, fine- to medium-crystalline dolostone. 

Ankhe/asma-lndex to Visean Shelf Margin, Western Interior of North America 825 
Table Cl. Foraminifers and algae in samples from Canada cited in appendix C 

[All samples registered in Geological Survey of Canada Locality Catalog. Identifications of fossils by B.L. 

Mamet] 

..::,t. 

iJ) (ii iJ) 

u > (ii tJl 

c C2 > iJ) 

(lj C2 ..::,t. 

·~ (lj ..::,t. -I c c ·..= ::J ::J ·o.. tJl 

Taxa 0 ..::,t. (lj ·:;;: 

~ ::J 

Vl $ E, 

N M M o:l L.l"l N 1.0 L.l"l ..... "1" N "1" "1" "1" 1.0 N M M 0'> 0'> 0'> "1" 0'> 0'> 1.0 1.0 1.0 1.0 M M 

u u u u u u 

Bnmsia sp. X 

Calcisphaera laevis Williamson X 

C. pachysphaerica (Pronina) X X 

C. sp. X X X 

Dainella sp. X X X 

Earlandia vulgaris (Rauzer-Chemoussova and Reidinger) X X X 

E. sp. X 

Earlandinella sp. X 

Endothyra sp. X X X 

Eoendothyranopsis hinduensis (Skipp) X X 

E. scitula (Toomey) X 

E. spiroides (Zeller) X X 

E. of the group E. spiroides (Zeller) X 

E. sp. X 

Eoforschia sp. X X X X 

Eoparastafella ova/is V dovenko X 

E. sp. X 

Eotextularia sp. X 

Eotuberitina sp. X 

Globoendothyra baileyi (Hall) X 

G. sp. X X X X X 

Issinella sp. X 

Kamaena sp. X 

Latiendothyra sp. X 

Orthriosiplzon sp. X 

Paleoberesella sp. X 

Parachaetetes regularis Konishi X 

Parathurammina sp. X X 

Planoendothyra sp. X 

Pohlia sp. X 

Priscella sp. X X 

Proninella sp. X 

Pseudoammodiscus sp. X 

Quasipolyderma sp. X 

"Septatournayella" henbesti Skipp, Holcomb, and Gutschick X 

Skippella sp. 

Spinoendothyra sp. 

Stacheoides sp. 

Collected samples: • GSC loc. C7347, slightly cherty, 

dolomitic, pelletoid-bearing, mixedskeletal wackestone having corals, 

brachiopods, spicules, calcareous 

algae, foraminifers, and pelmatozoan ossicles. 

• GSC loc. C7350, slightly cherty and 

dolomitic, pelletoid-pelmatozoanalgal lime packstone having brachiopods. 

• GSC loc. C7351, slightly cherty, 

dolomitic, pelletoid-bearing, 

826 Shorter Contributions to Paleontology and Stratigraphy 

X 

X 

X 

X X 

mixed-skeletal wackestone having 

corals, calcareous algae, foraminifers, pelmatozoan ossicles, and peloids. 

Age: Associated corals are Siphonodendron cf. S. oculinum Sando, S. sp., Vesiculophyllum sp., Zaphriphyllum sp., and Syringopora sp., which indicate 

Coral Zone IliA. Associated microfossils (GSC 

locs. C39452 and C39454) are assigned to Foraminifer Zone 10 (Mamet and others, 1986, p. 45). 

Ankhelasma ranges through the lower one-sixth of 

Foraminifer Zone 10 here. Microfossils of Foram-
inifer Zone 9 occur in GSC loc. C39450, 5.8 m (19 

ft) below the lowest occurrence of Ankhelasma here 

(Mamet and others, 1986, p. 45). This evidence 

indicates that Ankhelasma is restricted to the lower 

part of Composite Zone 12 at this locality. 

6. Mount Becker 

Location: Lat 54°31'25" N., long 120°39'45" W.; approximately 1.6 km (1 mi) southwest of the peak of 

Mount Beck~r, Monkman Pass 1:250,000-scale 

map sheet (NTS 931). 

Stratigraphic position: Mount Head Formation, 47.2-

47.9 m (155-157 ft) above base of 

formation and 0.6-1.2 m (2-4 ft) 

above base of Baril Member. 

Collection: • GSC loc. C7377: One silicified, immature 

specimen of A. sp. indet. 

Lithology: Cherty, pelletoid-bearing foraminifer-pelmatozoan lime grainstone having brachiopod and 

mollusk fragments. Collected sample is 

slightly cherty and dolomitic, foraminiferpelmatozoan grainstone having brachiopod 

and mollusk fragments and pelletoids. 

Age: Associated corals are Zaphriphyllum sp., which is 

compatible with Coral Zone IIIB. Microfossils of 

Foraminifer Zone 12 (GSC loc. C39199) occur 7.6 

m (25 ft) below Ankhelasma here (Mamet and 

others, 1986, p. 49). Therefore, the Ankhelasma 

occurrence at this locality is regarded as Composite 

Zone 14. 

7. Wapiti River 

Location: Lat 54°29'05" N., long 120°43'08" W.; approximately 3.2 km (2 mi) east of upper Wapiti 

River and 8 km (5 mi) northeast of Wapiti Pass, 

Monkman Pass 1:250,000-scale map sheet 

(NTS 931). 

Stratigraphic position: Mount Head Formation, lower part 

of Baril Member. 

Collections: • GSC loc. C64248, lower 1.7 m (5.8 ft) of 

Baril Member: Ten silicified specimens of 

A. sp. indet. 

• GSC loc. C 110912, lower part of Baril 

Member, 85.3 m (280 ft) below top of 

Mount Head Formation: Four silicified 

specimens of A. sp. indet. 

Lithology: Pelletoid-bearing, mixed-skeletal grainstone 

and subordinate fossiliferous dolostone, 

wackestone, and packstone. Principal bioclasts 

are corals, calcareous algae, brachiopods, 

foraminifers, and pelmatozoan ossicles. Some 

beds cherty. Collected sample (GSC loc. 

C64248) is pelletoid-bearing, mixed-skeletal 

grainstone having corals, brachiopods, bryozoans, foraminifers, intraclasts, and pelmatozoan ossicles, and calcisphere-peloid lime 

wackestone having foraminifers and spicules. 

Age: Associated corals are Siphonodendron sp., Zaphriphyllum sp., Vesiculophyllum sp., and Ekvasophyllum sp., indicative of Coral Zone IliA or B. Microfossils in GSC loc. C64248 (table Cl) are assigned 

to Foraminifer Zone 11 or basal 12. Hence, 

Ankhelasma occurs in Composite Zone 13 or the 

lower part of Composite Zone 14 at this locality. 

8. Belcourt Creek 

Location: Lat 54°21'30" N., long 120°29'40" W.; approximately 6.4 km (4 mi) northwest of Muinok 

Mountain at head of tributary to Belcourt 

Creek, Monkman Pass 1:250,000-scale map 

sheet (NTS 93I). 

Stratigraphic position: Mount Head Formation, 31.1-55.2 

m (102-181 ft) above base (Wileman(?) and Baril(?) Members). 

Collections: • GSC loc. C7399, 31.1 m (102 ft) above 

base of Wileman(?) Member: Two silicified 

specimens of A. sp. indet. 

• GSC locs. C7398 and C64249, 15m (49ft) 

above base of Baril(?) Member: Seventeen 

silicified specimens of A. typicum Sando. 

• GSC loc. C79699, 38.4 m (126 ft) above 

base of Wileman(?) Member: Thirty-eight 

silicified specimens of A. sp. indet. 

Lithology: The Wileman(?) Member is slightly dolomitic, 

peloid- and pelletoid-bearing, mixed-skeletal 

wackestone and subordinate shale and marlstone. Principal bioclasts are ostracodes, calcispheres, calcareous algae, molluscs, and pelmatozoan ossicles. 

The Baril(?) Member is mainly cherty, skeletaL dolomite grainstone and fossiliferous, 

medium- to coarse-crystalline dolostone and 

subordinate cherty, sparsely fossiliferous, fine 

crystalline dolostone ( dolomitized skeletal 

wackestone?). The main identifiable allochems are pelmatozoan ossicles and silicified 

corals. 

Collected samples: • GSC loc. C7399, foraminifer-peloid 

wackestone having calcispheres and 

pelmatozoan ossicles. 

• GSC loc. C7398, cherty, fossiliferous, fine- to medium-crystalline dolostone having foraminifers, corals, 

and pelmatozoan ossicles. 

• GSC loc. C64249, cherty, fossiliferous, medium-crystalline dolostone 

having corals and pelmatozoan ossicles. 

Age: Associated corals are Zaphriphyllum sp., Vesiculophyllum sp., Lophophyllum? sp., and Syringopora 

sp., which suggest Coral Zone IliA. Microfossils of 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 827 
Foraminifer Zone 11 (GSC loc. C39251) occur at 

the same stratigraphic level as GSC loc. C7399 and 

are also present (GSC loc. C39249) 45ft below GSC 

locs. C7398 and C64249 (Mamet and others, 1986, 

p. 51). This evidence indicates a Composite Zone 13 

occurrence for Ankhelasma here. 

9. Narraway River 

Location: Lat 54°10'35" N., long 120°15'20" W.; ridge 

north of Mount Hanington, approximately 4.8 

km (3 mi) southwest of Narraway River, 

Monkman Pass 1:250,000-scale map sheet 

(NTS 931). 

Stratigraphic position: 6.1 m (20 ft) above base of Turner 

Valley Formation to middle(?) part 

of Mount Head Formation (faulted 

section). 

Collections: • GSC loc. C79613, 6.1 m (20ft) above base 

of Turner Valley Formation: Five silicified, 

immature specimens of A. typicum? Sando. 

• GSC loc. C79627, (?)84.5 m (277ft) above 

base of Mount Head Formation (faulted 

section): One silicified specimen of A. sp. 

indet. 

• GSC loc. C79632, (?)126.2 m (414 ft) 

above base of Mount Head Formation 

(faulted section): One silicified specimen of 

A. typicum? Sando. 

• GSC loc. C 110911, upper part of Mount 

Head Formation (faulted section): Four 

silicified specimens of A. typicum? Sando. 

Lithology: Alternating succession of dolomitized, skeletal 

grainstone and sparsely fossiliferous, cherty, 

fine-crystalline dolomite and subordinate shale 

and dolomitic madstone. 

Collected samples: • GSC loc. C79613, slightly cherty, 

pelletoid-bearing, mixed-skeletal 

grainstone having foraminifers, bryozoans, and pelmatozoan ossicles. 

• GSC loc. C79627, cherty, fossiliferous, medium-crystalline dolostone 

having pelmatozoan ossicles and 

corals. 

• GSC loc. C79632, dolomitic, coralpelmatozoan-spicule packstone. 

Age: Associated corals are Vesiculophyllwn sp., ?Zaphriphyllum sp., and Siphonodendron sp., which suggest Coral Zone IliA or B. The lowest occurrence of 

Ankhelasma (GSC loc. C79613) is 44 ft below 

microfossils (GSC loc. C79617) assigned to Foraminifer Zone 10 by Mamet and others (1986, p. 55, 

56) and 186 ft above those (GSC loc. C79606) of 

828 Shorter Contributions to Paleontology and Stratigraphy 

Foraminifer Zone 9 (Mamet and others, 1986, p. 55, 

56). Specimens of Ankhelasma in GSC locs. 

C79627, C79632, and Cl10911 were not dated by 

using other fossils but are tentatively assigned to 

Foraminifer Zone 11 or 12 because of their stratigraphic position several hundred feet above GSC 

loc. C79613. Ankhelasma certainly occurs in Composite Zone 12 and probably ranges into Composite 

Zone 13 or 14 at this locality. 

10. Jarvis Lakes 

Location: Lat 54°06'45" N., long 120°13'15" W.; approximately 2.4 km (1.5 mi) north of Jarvis Lakes, 

Monkman Pass 1:250,000-scale map sheet 

(NTS 931). 

Stratigraphic position: Mount Head Formation, 7--43.6 m 

(23-143 ft) above base. 

Collections: • GSC C7421, Mount Head Formation, 

40.8-43.6 m (134-143 ft) above base: Four 

silicified specimens of A. typicum Sando. 

• GSC loc. C7422, Mount Head Formation, 

35.4-36.9 m (116-121 ft) above base: Two 

silicified, immature specimens of A. sp. 

indet. 

• GSC loc. C7423, Mount Head Formation, 7 

m (23 ft) above base: One silicified, immature specimen of A. sp. indet. 

Lithology: Alternating succession of dolomitized, commonly cherty, skeletal packstone and subordinate, sparsely fossiliferous, fine-crystalline 

dolomite. 

Collected samples: • GSC loc. C7421, slightly cherty, 

pelmatozoan dolomite grainstone. 

• GSC loc. C7422, brachiopod-bryozoan-pelmatozoan dolomite grainstone. 

• GSC loc. C7423, slightly cherty, 

very dolomitic, peloid-bearing 

mixed-skeletal packstone having 

calcispheres, bryozoans, foraminifers, and pelmatozoan ossicles. 

Age: Associated corals are Vesiculoph_vllum sp., Amplexizaphrentis sp. , Ekvasophyllum sp. , and Cyathaxonia sp., suggesting Coral Zone IliA or B. Microfossils (GSC loc. C39342, table Cl) of Foraminifer 

Zone 11 are associated with the corals in GSC loc. 

C7423. Microfossils (GSC loc. C39325, table Cl) 

of Foraminifer Zone 13 occur more than 150 ft 

above the highest occurrences of Ankhelasma (GSC 

locs. C7422 and C7421). The evidence suggests that 

Ankhelasma is in Composite Zone 13 and may range 

into Composite Zone 14 at this locality. 
APPENDIX D. CONTROL POINTS FOR 

CHRONOMETRIC LITHOFACIES PROFILES 

ACROSS INFERRED VISEAN SHELF MARGIN IN 

MONTANA (FIG. 13) 

[Interpretations of the stratigraphy differ from published 

references] 

Profile G-G' 

Unnamed inferred control point where no record 

exists, approximately 10 km west of inferred shelf 

margin. 

Rattler Gulch: Sees. 3, 4, and 9, T. 11 N., R. 13 W., 

Granite County, Montana. Unpublished preliminary 

study of section by Sando, Perry, and Schneider. 

Ages determined by corals, conodonts, and foraminifers. 

Morris Creek: Sees. 15 and 22, T. 11 N., R. 12 W., 

Granite County, Montana. Unpublished preliminary 

study of section by Sando and Perry. Ages determined by corals. 

Little Blackfoot River (Hope Creek): Sec. 29, T. 11 

N., R. 6 W., Lewis and Clark County, Montana. 

Unpublished preliminary study of section by Sando 

and Perry. Locality described by Bierwagen (1964). 

Ages determined by corals and foraminifers. 

Profile H-H' 

Unnamed inferred control point where no record 

exists, approximately 10 km west of inferred shelf 

margin. 

Lone Butte: Sec. 23, T. 23 N., R. 13 W., Flathead 

County, Montana. Graphic section by Sloss and 

Laird (1945, col. 3). Ages determined by brachiopods and corals. 

Hannan Gulch: Sec. 35, T. 22 N., R. 9 W., Teton 

County, Montana. Section described by Mudge and 

others (1962, fig. 3) and Mudge (1972, p. 

A93-A95). Ages determined by brachiopods and 

corals. 

Ankhelasma-lndex to Visean Shelf Margin, Western Interior of North America 829 

Chapter C 

Lithostratigraphy and Conodont 

Biostratigraphy Across the Lower-Middle 

Ordovician Disconformity (Early to Middle 

Whiterockian) at Pratt Ferry, Central 

Alabama 

By T.H. SHAW, KEITH E. ROBERSON, and ANITA G. HARRIS 

Description and conodont correlation of a stratigraphic unit that 

formed in paleokarst depressions at the onset of Middle Ordovician transgression 

U.S. GEOLOGICAL SURVEY BULLETIN 1895 

SHORTER CONTRIBUTIONS TO PALEONTOLOGY AND STRATIGRAPHY 

CONTENTS 

Abstract Cl 

Introduction Cl 

Acknowledgments C2 

Location and Procedures C2 

Previous Work C3 

Lithostratigraphy C3 

Newala Limestone C3 

Surface of the Lower-Middle Ordovician Disconformity C3 

Lenoir Limestone C3 

Cottingham Creek Member C3 

Mosheim Member CS 

Conodont Biostratigraphy CS 

Correlation of the Cottingham Creek Member C9 

Regional Distribution of the Cottingham Creek Member ClO 

Conclusions Cll 

References Cited C12 

PLATE 

[Plate follows References Cited] 

1. Selected conodonts from below and above the Lower-Middle Ordovician disconformity at Pratt Ferry, central Alabama. 

FIGURES 

1. Index map of central Alabama showing distribution of the eastern and western carbonate facies of the Middle and Upper Ordovician C2 

2. Chart showing historical development of stratigraphic nomenclature and correlation 

of some Upper Cambrian to Middle Ordovician rocks in central Alabama C4 

3. Photograph and diagrammatic sketch of the type section of the Cottingham Creek 

Member of the Lenoir Limestone showing location of conodont samples CS 

4. Photographs showing karstification features and bedforms at the Lower-Middle 

Ordovician disconformity, Pratt Ferry, Ala. C6 

5. Diagram showing stratigraphic ranges of selected conodont species in the upper 

part of the Newala Limestone through the lower part of the Mosheim Member of 

the Lenoir Limestone at Pratt Ferry C8 

6. Block diagram showing inferred paleogeographic setting during deposition of the 

Cottingham Creek Member of the Lenoir Limestone Cll 

TABLE 

1. Stratigraphic distribution of conodont species across the Lower-Middle Ordovician 

disconformity, Pratt Ferry, Ala. C7 

Contents Ill 

Lithostratigraphy and Conodont Biostratigraphy 

Across the Lower-Middle Ordovician Disconformity 

(Early to Middle Whiterockian) at Pratt Ferry, Central 

Alabama 

By T.H. Shaw,1 Keith E. Roberson/ and Anita G. Harris3 

Abstract 

Biostratigraphic and lithostratigraphic data from the 

Newala Limestone (Lower Ordovician) and the disconformably overlying Lenoir Limestone (Middle Ordovician) 

at Pratt Ferry, Alabama, indicate that (1) the upper Newala 

Limestone is of late Early Ordovician (late Canadian; lower 

Oepikodus communis Zone) age and the lower Lenoir 

Limestone is of early Middle Ordovician (late middle to 

early late Whiterockian; Phragmodus "pre-flexuosus" 

Zone to Cahabagnathus friendsvillensis Zone) age and (2) 

a basal, transgressive unit composed primarily of sandy 

dolostone, the Cottingham Creek Member of the Lenoir 

Limestone (new name), is the basal unit of the Middle 

Ordovician sequence locally. Where present, the Cottingham Creek Member aids in the identification of the 

Lower-Middle Ordovician disconformity in the eastern 

facies of the Middle Ordovician of Alabama. 

The Cottingham Creek Member was deposited in 

paleokarst depressions developed on the Newala Limestone during the earliest Middle Ordovician. Areal distribution and lithostratigraphic and biostratigraphic data 

prove conclusively that the Cottingham Creek Member is 

geographically, lithologically, and chronologically distinct 

from the Attalla Chert Conglomerate Member of the 

Chickamauga Limestone of northeastern Alabama, a unit 

that also lies at the base of the Middle Ordovician transgressive sequence. The Cottingham Creek does appear to 

be correlative or partly correlative, however, with some of 

the other units that lie at the base of the Middle Ordovician sequence in the southern Appalachians. It is correlative with the basal part of the Wells Creek Dolomite in 

south-central Tennessee and the Douglas Lake Member of 

the Lenoir Limestone in northeastern Tennessee. It may 

be the same age as the lower part of the Pond Spring 

Formation in northwestern Georgia but is considerably 

Manuscript approved for publication April 27, 1989. 1 Department of Geology, Queens College, City University of New 

York, Flushing, NY 11367. 2

Department of Geological Sciences, University of Tennessee, 

Knoxville, TN 37996. 3

U.S. Geological Survey, 970 National Center, Reston, VA 22092. 

older than the upper part of the Pond Spring, indicating 

the possibility of a disconformity within the Pond Spring. 

INTRODUCTION 

Recognition of the contact between the New ala Limestone (Lower Ordovician) and the disconformably overlying 

Lenoir Limestone (Middle Ordovician), which occur 

together only east of the Helena fault, has long been a 

problem for geologists mapping in Alabama. This contact, 

the regionally extensive Lower-Middle Ordovician disconformity, is difficult to locate because of the ( 1) striking 

similarity between the Newala Limestone and the Mosheim 

Member of the Lenoir Limestone, the units that, in most 

places, bound the disconformity, (2) lack of appreciable 

relief and other reliable exposure indicators on the surface 

of disconformity (Roberson, 1988), and (3) generally poor 

exposure of this stratigraphic interval. The disconformity, 

however, is well exposed near Pratt Ferry, Bibb County, 

Ala. (fig. 1), where it is clearly delineated by a large 

paleokarst collapse feature containing conglomeratic dolostone that differs significantly from either the Newala or 

Mosheim limestones. 

On the basis of new data (Shaw, 1987; Roberson, 

1988), this report describes the stratigraphy across the 

Lower-Middle Ordovician disconformity at Pratt Ferry and 

establishes the age of the basal dolostone of the Middle 

Ordovician carbonate sequence, which is named herein the 

Cottingham Creek Member of the Lenoir Limestone. In 

addition, the age and origin of the Cottingham Creek 

Member are compared to those of units occupying a similar 

stratigraphic position elsewhere in Alabama and in Georgia 

and Tennessee. The Cottingham Creek Member is inferred 

to have been deposited in paleokarst depressions on the 

post-Knox erosion surface during the late middle to early 

late Whiterockian. This report also establishes the age of the 

upper Newala Limestone at Pratt Ferry as late Early 

Ordovician (lower Oepikodus communis Zone) and discusses the magnitude of the post-Knox hiatus and the nature 

of the disconformity surface. 

Lithostratigraphy and Conodont Biostratigraphy at Pratt ferry, Central Alabama Cl 
sr 

30 KILOMETERS 

EXPLANATION 

rna Eastern Facies 

~ Western Facies 

Figure 1. Distribution of the eastern and western carbonate facies of the Middle 

and Upper Ordovician in central Alabama. The type section of the Cottingham 

Creek Member of the Lenoir Limestone is at Pratt Ferry (lower left). Modified from 

Neathery and Drahovzal, 1986. 

Acknowledgments 

Portions of this investigation were undertaken as parts 

of master's theses by T.H. Shaw at Emory University and 

K.E. Roberson at the University of Alabama, Tuscaloosa. 

Shaw gratefully acknowledges the aid of his advisors, 

Pamela Gore and J.E. Repetski; ARCO Oil and Gas 

Company provided financial support for part of his work; 

David Hooks, formerly of the University of Alabama, 

helped him sample the section at Pratt Ferry, and the Illinois 

State Geological Survey provided facilities and some financial support during preparation of the manuscript. Roberson 

is indebted to his advisors, D.J. Benson, W.G. Hooks, and 

C.W. Stock, for sharing with him their knowledge of the 

Ordovician stratigraphy of Alabama. Some of Roberson's 

investigations were carried out under the auspices of the 

Geological Survey of Alabama, and he appreciates that its 

personnel, particularly G.M. Guthrie, Robert Mink, W.E. 

Osborne, Dorothy Raymond, W.E. Smith, and B.N. Tew, 

were readily accessible for discussions. Roberson also 

wishes to acknowledge financial support provided by Sigma 

C2 Shorter Contributions to Paleontology and Stratigraphy 

Xi and the Southeastern Section of the Geological Society 

of America. Special thanks are due J.E. Repetski, U.S. 

Geological Survey, for sharing his knowledge of Early 

Ordovician conodonts. We all thank Barbara Stiff, Illinois 

State Geological Survey, for drafting most of the illustrations. 

LOCATION AND PROCEDURES 

The exposure near Pratt Ferry is on the east cutbank 

of the Cahaba River, north of the Pratt Ferry Bridge, 0.32 

km north of the confluence of Cottingham Creek and the 

Cahaba River, NE lf-+ NE 1/4 sec. 33, T. 24 N., R. 10 E., lat 

33°01'25" N., long 87°01'18" W., West Blocton East 

7.5-minute quadrangle, Bibb County, Ala. (fig. 1). The 

section is on the north limb of the Bibb County syncline in 

the Helena thrust sheet. 

The section was measured and described, and 34 

samples were collected for conodont analysis. Thin sections 

and acetate peels were made from selected lithologies. The 
conodont collections are reposited in the U.S. Geological 

Survey conodont laboratory, Reston. Va. 

PREVIOUS WORK 

The Lower and Middle Ordovician stratigraphic subdivisions proposed by Butts (1926) have been retained with 

modification by most workers in Alabama. Butts (1926) 

recognized that the Upper Cambrian-Lower Ordovician and 

Middle Ordovician carbonate sequences are separated by an 

unconformity. and he identified the Mosheim Limestone as 

the oldest Middle Ordovician unit in the Cahaba Valley east 

of the Helena fault (fig. 2). The Mosheim is presently 

considered to be a member of the Lenoir Limestone 

(Drahovzal and Neathery. 1971: Roberson. 1988) (fig. 2). 

Drahovzal and Neathery (1971) observed that. 

although Butts (1926) recognized the facies relations of 

units within the post-Knox sequence of central Alabama. 

his nomenclature reflected a time-stratigraphic succession 

or "layer-cake'' stratigraphy. The general absence of biostratigraphic control and the structural complexity of the 

Valley and Ridge province resulted in acceptance of Butts' 

(1926) stratigraphic succession by most subsequent workers. On the basis of lithostratigraphic and paleontologic 

data, Drahovzal and Neathery (1971) revised the stratigraphic nomenclature to reflect the facies relations of the 

units recognized by Butts and identified a western. chiefly 

carbonate facies and an eastern, chiefly clastic facies 

structurally separated by the Helena fault (figs. 1. 2). 

Where the Attalla Chert Conglomerate Member is the 

lowest unit of the Chickamauga Limestone in the Middle 

Ordovician western facies, it is the basal transgressive unit 

of the Middle Ordovician (fig. 2). The Attalla disconformably overlies the Copper Ridge Dolomite. Chepultepec 

Dolomite. or Longview Limestone and is conformably 

overlain by the Chickamauga Limestone. The lower Chickamauga in Alabama is late Whiterockian to Blackriveran in 

age (Hall and others. 1986). 

The Attalla Chert Conglomerate Member is absent in 

the eastern facies of the Middle Ordovician of Alabama. 

and basal members of the Lenoir Limestone (Middle Ordovician) disconformably overlie the Newala Limestone (upper 

Lower Ordovician) or Odenville Limestone (uppermost 

Lower to possibly lowermost Middle Ordovician) (fig. 2). 

Conodonts indicate that the Lenoir is of middle to late 

Whiterockian age and is time transgressive westward (Drahovzal and Neathery, 1971; Hall and others, 1986). 

LITHOSTRATIGRAPHY 

A relatively complete section of lower Paleozoic 

rocks is exposed in the east cutbank of the Cahaba River 

north of the Pratt Ferry Bridge and includes the Chepultepec, Longview, and New ala formations and a nearly complete Middle Ordovician sequence from the base of the 

Lenoir Limestone through the Athens Shale. The focus of 

this report is on the disconformable contact between the 

Newala and Lenoir Limestones. 

Newala Limestone 

At Pratt Ferry, the New ala Limestone is approximately 55 m thick and consists of medium-bedded, lightgray to very light gray, yellowish-gray-weathering, highcalcium limestone interbedded with thin layers of coarsely 

crystalline, light-brownish-gray-weathering, light-gray 

dolostone. The limestone is predominantly mudstone and 

peloidal packstone/wackestone. Thin beds of sucrosic dolostone. arenaceous mudstone, and grainstone are present 

locally within the lower Newala. With the exception of 

locally abundant gastropods, megafossils are rare. The 

Newala conformably overlies the Longview Limestone and 

is disconformably overlain by the Lenoir Limestone. 

Surface of the Lower-Middle Ordovician 

Disconformity 

The disconformable contact between the Newala 

Limestone and the overlying Cottingham Creek Member of 

the Lenoir Limestone at Pratt Ferry has a minimum relief of 

14 m and forms a paleotopographic low that is at least 48 m 

across (fig. 3). This depression truncates bedding within the 

upper Newala. The walls of the depression are very irregular. and the contact between the Newala and rocks filling 

the depression is sharp (figs. 4A, B). A slightly tilted, 

downdropped block of Newala Limestone occupies the 

center of the depression (fig. 3). Relief on the paleoerosion 

surface away from the depression is low ( ± 10 em), and the 

disconformity is represented by a sharp and irregular 

contact. 

The absence of slickensides, fault gouge or breccia, 

and the continuity of bedding within the depression-fill 

lithologies and within the Newala on either side of the 

depression suggest that the depression is the result of karst 

collapse and not faulting. 

Lenoir Limestone 

Cottingham Creek Member 

The paleotopographic depression in the Newala 

Limestone is filled with a variety of thin- to mediumbedded, laterally discontinuous, argillaceous, brownishgray- to light-brownish-gray-weathering, moderate- to 

light-brown dolostone. These rocks are here named the 

Cottinoham Creek Member of the Lenoir Limestone for 0 

Cottingham Creek, Bibb County, Ala. The exposure near 

Lithostratigraphy and Conodont Biostratigraphy at Pratt Ferry, Central Alabama C3 
1 

Cf) 

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2 

DRAHOVZAL AND 

NEATHERY, 1971 

WESTERN 

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Formation 

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THIS REPORT 

WESTERN 

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Copper 

Ridge 

Dolomite 

Figure 2. Historical development of stratigraphic nomenclature and correlation of some Upper Cambrian to 

Middle Ordovician rocks in central Alabama. CCM (shaded unit), Cottingham Creek Member; AC, Attalla 

Chert Conglomerate Member; OL, Odenville Limestone. 

Pratt Ferry, described above, is designated the type section. 

The base of the member consists of recrystallized conglomeratic dolostone containing pebbles, cobbles, and boulders 

of lime mudstone, packstone/grainstone, and dolomudstone. The clasts are as much as 30 em in diameter, and all 

C4 Shorter Contributions to Paleontology and Stratigraphy 

appear to have been derived from the Newala Limestone 

(fig. 4C). The basal conglomerate is overlain by darkbrown, bryozoan-rich dolowackestone and dolomudstone; 

tan, porous dolomudstone; burrowed dolomudstone; and 

greenish-gray dolosiltite. Crossbedding is well developed 
8 

Newala Limestone 

Cottingham Creek Member 5 m 1 

Figure 3. (A) Type section of the Cottingham Creek Member of the Lenoir Limestone and (B) location of conodont 

samples 5 and 7 to 23 and truncation of bedding within the Newala Limestone and Cottingham Creek Member. Sample 

numbers are keyed to table 1. 

updip and at the base of the unit (fig. 4D). The uppermost 

part of the member is a thick-bedded, massive, sandy, 

argillaceous, brownish-gray dolostone that is laterally continuous across the depression. 

Megafossils in the Cottingham Creek Member are 

predominantly bryozoans but also include brachiopods and 

large specimens of the gastropod Maclurites magnus 

(LeSueur). The occurrence of these fossils indicates that the 

depression-fill deposits formed under marine conditions, 

probably during the earliest phase of the post-Knox transgression. 

The maximum thickness of the Cottingham Creek 

Member is uncertain because the paleotopographic depression that forms its base extends beneath the surface of the 

Cahaba River; it is estimated to be 16 m thick. The 

Cottingham Creek at Pratt Ferry forms a knoll, possibly 

because it is composed of dolostone that is relatively more 

resistant than the adjacent limestones; this topographic 

characteristic may aid in its recognition elsewhere. 

Mosheim Member 

The Mosheim Member of the Lenoir Limestone 

overlies the Cottingham Creek Member. Its lower part is 

predominantly medium- to thick-bedded, massive, mediumlight- to light-gray, fenestral lime mudstone containing a 

sparse fauna of ostracodes and gastropods. These beds 

grade upward into thin- to medium-bedded, slightly more 

argillaceous, fenestral mudstone that locally contains abundant gastropods. The contact between the Mosheim and 

Cottingham Creek Members is sharp and irregular and may 

represent an erosional surface; if so, the magnitude of the 

hiatus is less than a single conodont zone. 

CONODONT BIOSTRATIGRAPHY 

The rather complete exposure of Ordovician rocks in 

the vicinity of Pratt Ferry, Ala., has become a key section 

for biostratigraphic studies in the southernmost Appalachians, particularly for Middle Ordovician index fossil 

groups (brachiopods: Cooper, 1956; conodonts: Sweet and 

Bergstrom, 1962, Bergstrom, 1971, and Schmidt, 1982; 

graptolites: Ruedemann, 1947, Decker, 1952, and Finney, 

1977, 1984). In this report, we add to the paleontologic 

documentation of this section the distribution of conodonts 

in several meters of beds both below and above the 

Lithostratigraphy and Conodont Biostratigraphy at Pratt Ferry, Central Alabama C5 
Figure 4. Karstification features and bedforms at the Lower-Middle Ordovician disconformity, Pratt Ferry, Ala. A, Sharp, 

vertical contact (circled area) between the Newala Limestone (lighter gray) and the Cottingham Creek Member of the 

Lenoir Limestone. B, Close-up of contact circled in A. C, Boulder of Newala Limestone in the lower Cottingham Creek 

Member. D, Crossbedded dolostone at base of Cottingham Creek Member. 

disconformity separating the Newala and Lenoir Limestones, an interval not covered by previous conodont 

studies. 

Of the 34 samples collected for conodont analysis, 31 

yielded conodonts. Sample size ranged from 3.9 to 12.1 kg 

(table 1). Large samples are required to recover even a few 

conodont elements from either the Newala Limestone or the 

lower members of the Lenoir Limestone. The ranges of 

selected conodont species in the section are shown in figure 

5; conodont species distribution is summarized in table 1. 

Conodonts from this section have a color alteration index of 

1.5; this index indicates the host rock reached burial 

temperatures of at least 60 to 90 °C. 

The conodont fauna from the Newala is dominated by 

elements of Diaphorodus delicatus (Branson and Mehl) (pl. 

1, figs. 18, 19) and Eucharodus parallelus (Branson and 

Mehl) and subordinate numbers of elements of Cristodus 

loxoides Repetski (pl. 1, fig. 21), Drepanodus concavus 

(Branson and Mehl) (pl. 1, fig. 22), Drepanoistodus 

C6 Shorter Contributions to Paleontology and Stratigraphy 

suberectus (Branson and Mehl) subsp. A sensu Repetski, 

1982a, Glyptoconus quadraplicatus (Branson and Mehl), 

Oneotodus costatus Ethington and Brand (pl. 1, fig. 20), 

Scolopodus cornutiformis Branson and Mehl, "Scolopodus" 

emarginatus Barnes and Tuke (pl. 1, fig. 23), Tropodus 

comptus (Branson and Mehl), and Ulrichodina abnormal is 

Branson and Mehl. 

Although Oepikodus communis has not been found in 

the Newala Limestone, probably due to unfavorable environmental conditions, Diaphorodus delicatus, a species 

whose first appearance approximates the base of the 0. 

communis Zone in rocks that formed in warm, shallow, 

possibly hypersaline marine environments (Repetski, 

1985), occurs throughout the upper 25 m of the formation in 

the Pratt Ferry section. D. delicatus is known to range into 

the very earliest Whiterockian. Its occurrence in the 

Newala, together with representatives of Cristodus loxoides 

and Glyptoconus quadraplicatus (table 1), species that are 

not known to range into the Whiterockian, indicates that the 
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lithostratigraphy and Conodont Biostratigraphy at Pratt Ferry, Central Alabama C7 
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e Highest occurrence in 

A B c D E Newala Limestone 

Figure 5. Ranges of selected conodont species in the 

upper part of the Newala Limestone and lower part of the 

Lenoir Limestone at the type section of the Cottingham 

Creek Member of the Lenoir Limestone. Extension of 

ranges below and above the stratigraphic levels of the 

Newala and the Lenoir Limestones sampled for this study 

are, for the Newala, from Shaw (1987) and, for the Lenoir, 

from Sweet and Bergstrom (1962), Bergstrom (1971), and 

Schmidt (1982). (A) Drepanodus concavus, (B) Eucharodus 

upper Newala was deposited during 0. communis Zone 

time ( = late Early Ordovician). Moreover, the presence of 

C. loxoides throughout much of this interval further restricts 

these beds to the lower part of the 0. communis Zone. 

The conodont fauna of the Cottingham Creek Member of the Lenoir Limestone consists chiefly of, in order of 

decreasing abundance, elements of Panderodus spp. (pl. 1, 

fig. 17), Ansella nevadensis (Ethington and Schumacher), 

Plectodina joachimensis (Andrews) (pl. 1, fig. 15), Beladina monitorensis Ethington and Schumacher, Drepanoistodus spp., Erraticodon aff. E. balticus Dzik, and "Scandodus" sinuosus Mound. Reworked elements of 

Drepanodus concavus, Eucharodus parallel us, Glyptoconus quadraplicatus, Ulrichodina abnormalis, and "Scolopodus" emarginatus are locally present within the Cottingham Creek Member. 

With the exception of "Scandodus" sinuosus, the 

Middle Ordovician species recovered from the Cottingham 

Creek Member also occur in the overlying Mosheim Member. In addition, elements of Tripodus sp. , Oistodus cf. 0. 

lanceolatus Pander, Drepanoistodus cf. D. forceps (Lindstrom), Cahabagnathus friendsvillensis (Bergstrom) (pl. 1, 

fig. 1), and Phragmodus flexuosus Moskalenko (pl. 1, figs. 

2-4), first occur in the Mosheim Member. 

Specimens of "Scandodus" sinuosus are the oldest, 

possibly indigenous conodonts in the basal beds of the 

Cottingham Creek Member. If they are indigenous and not 

C8 Shorter Contributions to Paleontology and Stratigraphy 

F G H 

parallelus, (C) Gfyptoconus quadrapficatus, (D) Oneotodus costatus, (E) Ulrichodina abnormafis, (F) Tropodus 

comptus, (G) Cristodus loxoides, (H) Diaphorodus de/icatus, (I) "Scolopodus" emarginatus, (J) Ansel/a nevadensis, 

(K) Belodina monitorensis, (L) Plectodina joachimensis, 

(M) "Scandodus" sinuosus, (N) Leptochirognathus 

quadratus, (0) Erraticodon aff. E. balticus, (P) Cahabagnathus friendsvillensis, and (Q) Phragmodus flexuosus. 

Conodont distribution and abundance are given in table 1. 

reworked, then their occurrence in this member, together 

with elements of Plectodina joachimensis and Erraticodon 

aff. E. baltic us, restricts the age of these beds to the 

Phragmodus "pre-flexuosus" Zone of Sweet (1984). The 

upper limit of the range of "S." sinuosus and the lower limit 

of the ranges of P. joachimensis and E. balticus appear to 

be within this chronozone. If, on the other hand, the 

specimens of "S." sinuosus are reworked (these specimens 

are limited to beds that contain other reworked conodont 

elements), then the age of the Cottingham Creek Member is 

less constrained because all other conodonts within this unit 

are relatively long ranging within the middle to late Whiterockian. Elements of Cahabagnathus friendsvillensis first 

appear several meters above the base of the Mosheim 

Member in this exposure (fig. 5), indicating a level within 

the C. friendsvillensis Zone of the North American conodont zonation (Sweet, 1984) or the P. serra Zone of the 

Baltoscandia conodont zonation. Bergstrom (1971 and oral 

commun., 1988) recovered elements of Pygodus serra 

Hadding and C. friendsvillensis from near the top of the 

Lenoir to at least 65 m below its top in the vicinity of Pratt 

Ferry. Bergstrom (1971) has also shown that the boundary 

between the P. serra-P. anserinus Zones lies near the top 

of the Pratt Ferry Formation (Cooper, 1956), about 10 m 

above the top of the Lenoir Limestone in this vicinity. The 

known range of C. friendsvillensis is from near the base to 

near the top of the P. serra Zone (Bergstrom, 1983). Its 
presence throughout the nearly 75 m of Lenoir Limestone 

that overlies the Cottingham Creek and lower Mosheim 

beds in the Pratt Ferry section suggests that the Cottingham 

Creek Member is no younger than the early part of the C. 

friendsvillensis Zone and could well be as old as, but no 

older than (based on the presence of Plectodina joachimensis and Erraticodon aff. E. balticus), the Phragmodus 

"pre-jlexuosus" Zone. In terms of the Whiterockian Series, 

the Cottingham Creek Member is of late middle to early late 

Whiterockian age. 

CORRELATION OF THE COTTINGHAM CREEK 

MEMBER 

The Cottingham Creek Member of the Lenoir Limestone is differentiated from the Attalla Chert Conglomerate 

Member of the Chickamauga Limestone by the absence of 

chert, the sparsity of cobble- and boulder-sized clasts, and 

the absence of sandstone and (or) green shale in the 

Cottingham Creek Member. Lithologic differences between 

the Cottingham Creek and Attalla Chert Conglomerate 

Members are the result of differences in provenance; that is, 

differences in the rock units that underlie them and the 

nature of the paleotopographic depressions in which each 

member was deposited . 

On the basis of conodonts in Chickamauga Limestone 

beds above the Attalla Chert Conglomerate Member at the 

Red Mountain roadcut in Birmingham, Ala., Hall and others 

(1986) reported the age of the Attalla as early Blackriveran. 

Their lowest, biostratigraphically useful, Middle Ordovician conodont collection is from about 12 m above the top 

of the Attalla, and it and overlying collections only indicate 

that the Attalla is no younger than latest Whiterockian to 

early Blackriveran. About 20 km east-northeast of Birmingham, we collected one conodont sample from a Middle 

Ordovician dolomitic fenestral mudstone , 2 m below the 

Attalla and another sample from within a noncherty phase 

of the Attalla (USGS collections 10317-CO and 

1 0316-CO, from outcrops on the northern side of a stream 

that flows between Butler and Foster Mountains, 400 m east 

of the Clay-Palmerdale Road and 2 km northwest of Clay, 

Jefferson County, SE '/4 NW '/4 sec . 23, T. 15 S., R. 1 W., 

lat 33°42.8' N. , long 86°37.1' W. , Argo 7.5-minute quadrangle, Ala.). The presence of representatives of Phragmodus injlexus Stauffer and Plectodina n. sp. of Votaw (1971) 

in the lower sample and of these two species and Appalachignathus delicatus Bergstrom and others in the Attalla 

Chert Conglomerate Member sample indicates that the 

Attalla is of highest C. sweeti Zone to lowest E. quadridactylus Zone age. Thus, even though the Cottingham 

Creek and the Attalla Chert Conglomerate Members formed 

in similar paleogeographic settings and are the basal units of 

the Middle Ordovician carbonate sequence that disconformably overlies the Knox Group, they are neither coeval nor 

contiguous (fig. 2). The Attalla occurs only west of the 

Helena fault, whereas the Cottingham Creek is found only 

east of it. 

The age relation of the Cottingham Creek Member to 

the Pond Spring Formation of northwestern Georgia is more 

complex. The basal few meters of the Pond Spring are 

lithologically similar to the Cottingham Creek Member and 

occupy a similar stratigraphic position. In the vicinity of 

Chickamauga, Ga., its type area, the Pond Spring ranges 

from about 75 to 95 m in thickness (Milici and Smith, 

1969). According to Hall and others (1986), the lowest 

occurrence of Plectodina aculeata (Stauffer) in this area is 

about 13 m below the top of the formation and about 14 m 

above the only sample containing Phragmodus jlexuosus 

and P. injlexus. These data indicate that the lowest sample 

containing P. aculeata is within the P. aculeata Zone and 

that at least the upper Pond Spring is of Blackriveran age 

and, like the Attalla Chert Conglomerate Member, is 

younger than any part of ·the Lenoir Limestone at Pratt 

Ferry. According to Schmidt (1982), two collections from 

the lower 20m of the Pond Spring contain conodonts much 

older than those from the upper part of the formation. These 

collections contain abundant representatives of Phragmodus 

jlexuosus, lesser numbers of its ancestor P. "pre-jlexuosus," 

and forms transitional between them. These data seem to 

indicate that at least the lower 20 m of the Pond Spring are 

of lowest C. friendsvillensis Zone age. This age is somewhat surprising, because the highest occurrence of this 

species association is only about 30 m below Pond Spring 

beds that contain P. aculeata and that are of definitive 

Blackriveran age. Moreover, the regional depositional 

framework and lithology of the Pond Spring suggest rapid 

deposition. A disconformity may occur within the middle 

Pond Spring, or alternatively, the specimens assigned by 

Schmidt (1982) to forms ancestral and transitional to P. 

jlexuosus may be ecophenotypes that appear late in the 

range of P. jlexuosus. Schmidt ( 1982) expressed similar 

concern but offered no suggestions about the apparent long 

time interval represented by the lower and middle Pond 

Spring Formation. This problem cannot be resolved without 

additional data. Nonetheless, at least the lower 20 m of the 

Pond Spring may be equivalent to the Cottingham Creek 

Member. 

The Cottingham Creek Member is at least partly 

correlative with the base of the Wells Creek Dolomite (as 

used by Bentall and Collins, 1945), the unit that disconformably overlies the Knox Group in the subsurface of 

south-central Tennessee. Conodont collections from the 

basal few meters of the Wells Creek in four cores from 

Bedford and Maury Counties (Repetski, 1982b, and unpub. 

data) contain representatives of Multioistodus subdentatus 

Cullison and Phragmodus jlexuosus, indicating a level low 

in the C. friendsvillensis Zone. Except for a few redeposited 

Early Ordovician specimens, the Middle Ordovician conodonts in these collections appear to be indigenous. The 

lithostratigraphy and Conodont Biostratigraphy at Pratt Ferry, Central Alabama C9 
base of the Wells Creek Dolomite in at least Bedford and 

Maury Counties, Tenn., is the same or nearly the same age 

as the Cottingham Creek Member and appears to be the 

same age as the lower part of the Pond Spring Formation of 

northwestern Georgia. 

The Cottingham Creek Member is probably correlative with the Douglas Lake Member of the Lenoir Limestone in Tennessee (Laurence, 1944; Bridge, 1955; Harris, 

1982). Like the Cottingham Creek, the Douglas Lake 

Member formed within paleokarst depressions on the postKnox erosion surface. Rocks of the Cottingham Creek are 

similar to rocks assigned to unit B by Laurence (1944), 

which include crossbedded conglomeratic dolostone and 

fossiliferous argillaceous dolostone. The Douglas Lake 

Member disconformably overlies the Mascot Dolomite, a 

cherty dolomite that is coeval in part with the Newala 

Limestone. The Douglas Lake consists predominantly of 

noncarbonate rocks that contain chert locally and thus are 

unlike rocks of the Cottingham Creek Member. Differences 

in rock type reflect the composition of the underlying Knox 

Group and the paleotopography and paleoregolith developed on the surface of disconformity. 

Laurence ( 1944) reported the age of the Douglas Lake 

Member as post-Canadian and pre-Chayzan or Chayzan, or 

middle to late Whiterockian of current usage (Ross and 

others, 1982). Harris (1982) and Broadhead and others (in 

press) reported elements of Phragmodus flexuosus from 

about 3 m above the top of the Douglas Lake Member in the 

main body of the Lenoir Limestone. In a collection taken 20 

m higher in the section from the overlying Whitesburg 

Formation, they reported the presence of Eoplacognathus 

foliaceus (Fahraeus), Cahabagnathus friendsvillensis, and 

Pygodus serra. These data indicate that the Douglas Lake 

Member is no younger than the lower part of the C. 

jriendsvillensis Zone and is of that age or of slightly older 

late P. "pre-flexuosus" Zone age and falls within the age 

range determined for the Cottingham Creek Member. 

REGIONAL DISTRIBUTION OF THE 

COTTINGHAM CREEK MEMBER 

Rocks resembling and occurring at the same stratigraphic level as the Cottingham Creek Member have been 

identified near Fremont Gap, St. Clair County, Ala. (SE l/4 

sec. 9, T. 14 S., R. 5 E.) (Roberson, 1988). At both Pratt 

Ferry and Fremont Gap, these rocks occur in paleokarst 

depressions developed on the Newala Limestone. At Fremont Gap, the dolostones are very similar to those at the 

type section of the Cottingham Creek; however, the basal 

conglomerates are less conspicuous, and the geometry of 

the deposit is difficult to determine because of extensive 

covered intervals. 

The Cottingham Creek is apparently restricted to 

areas where the Newala Limestone is the highest unit 

Cl 0 Shorter Contributions to Paleontology and Stratigraphy 

preserved beneath the Lower-Middle Ordovician disconformity. This may be related to the character of the New ala, 

local structure, magnitude of the hiatus, and (or) proximity 

to the source area for clasts within Cottingham Creek 

conglomerate. 

Paleotopographic depressions resulting from karst 

collapse or dissolution have not been observed where the 

Odenville Limestone is the highest unit preserved beneath 

the post-Knox Group disconformity. Dolomitic, siliceous, 

and argillaceous impurities within the Odenville, typically 

10 to 12 percent, may have inhibited the development of 

large subsurface solution cavities by retarding migration of 

ground water. In contrast, the Newala Limestone rarely 

contains more than two percent noncarbonate impurities 

and appears to be very susceptible to aqueous dissolution. 

Subtidal, chert-free, coarsely crystalline dolostone 

within the Newala Limestone may increase its dissolution 

potential relative to that of the Odenville or Longview 

Limestones. Rocks of this type are highly susceptible to 

sinkhole formation (Brink, 1984). Holocene caverns within 

the lower Newala are commonly encountered during drilling in the type area of the formation (B. Kitchens, Vulcan 

Materials Corporation, and T. Flannery, Blue Circle Industries, oral commun., 1986). A collapsed cave occurs within 

the lower Newala near the base of the Vulcan Materials 

Corporation quarry north of Calera, Ala.; the age of this 

feature is unknown. Holocene sinkholes in the type area of 

the Newala are most common in the subjacent Longview 

Limestone because this unit contains tectonically fractured 

chert that provides pathways for fluid migration (LaMoreaux, 1984). 

Local structure may also significantly influence the 

development of relief on the Knox paleoerosion surface. 

The Attalla Chert Conglomerate Member is restricted to an 

area between the Anniston and Harpersville lineament 

complexes (fig. 1; Drahovzal, 1974). Moreover, the thickest and coarsest development of the Attalla is associated 

with the lineament complexes (Drahovzal and others, 

1974); within the Anniston lineament complex, high-angle 

faults vertically offset the top of the Knox Group by as 

much as 45 m. These faults may be the result of differential 

movement of crustal blocks contemporaneous with, or prior 

to, deposition of the Attalla Chert Conglomerate Member 

(Drahovzal and others, 1974). These data imply that development of the Attalla is related to regional structural 

features. 

In contrast, the known Cottingham Creek deposits do 

not appear to be associated with regional structures. At the 

type section of the Cottingham Creek, there is no evidence 

for tectonic deformation of the Newala prior to deposition 

of the Cottingham Creek, and stratigraphy appears to be the 

controlling factor for paleokarst development. 

Duration of exposure may also significantly influence 

the configuration of the paleoerosion surface developed on 

the Knox Group. Repetski and Harris (1986) and Roberson 
NW 

EXPLANATION 

j:}~:)J Lenoir Limestone (main body) 

~ Mosheim Member 

- Cottingham Creek Member 

~ Newala Limestone 

(ii:iii:::j:f:::::::j Odenvi lle Limestone 

I 

/ 

/ 

/ 

/ 

I 

/ 

/ 

/ 

/ 

NWB ---

Figure 6. Inferred paleogeographic setting during deposition of the Cottingham Creek Member of the Lenoir Limestone 

in what is now part of central Alabama. NWB, normal wave base. 

(1988) reported that the magnitude of the post-Knox, 

Middle Ordovician disconformity generally decreases eastward in the Appalachian basin. In addition, Neathery and 

Drahovzal (1971 , 1986) reported a dark-maroon shale and a 

red to pink, cherty claystone near the base of the Attalla 

Chert Conglomerate Member and interpreted these rocks to 

represent a paleosol developed on the Knox surface. The 

apparent decrease in magnitude of the post-Knox, Middle 

Ordovician disconformity eastward and the development of 

a paleosol at the base of the Attalla imply that rocks below 

the disconformity in the western facies belt may have been 

exposed long enough to develop a valley and hill topography having a primarily surficial drainage, whereas rocks of 

the eastern facies belt may have been submerged before a 

surficial drainage pattern could be established. Furthermore, tectonic deformation of the chert-bearing rocks 

underlying the Attalla Chert Conglomerate, associated with 

the Anniston and Harpersville lineaments, may have accelerated degradation of the Knox paleosurface and dissolution 

in the subsurface. The Attalla Chert Conglomerate Member 

has a greater areal distribution than the Cottingham Creek 

Member. This supports the hypothesis that the Attalla Chert 

Conglomerate Member may represent valley-fill deposits, 

rather than locally restricted karst-depression fills represented by the Cottingham Creek deposits. 

Neathery and Drahovzal (1971, 1986) reported that 

the Attalla Chert Conglomerate Member near Hensley 

Mountain, Ala., exhibits an upward size gradation and an 

increase in clast size approximately 12 m above the base of 

the unit. They attributed this increase to renewed influx of 

clastic material into the basin. Furthermore, some clasts are 

rounded and suggest mechanical transportation. The 

absence of conglomerate above the basal beds of the 

Cottingham Creek Member and the general angularity of 

clasts in these beds indicate their local derivation. 

Figure 6 shows our interpretation of the paleogeographic setting when Cottingham Creek deposits accumulated in karst depressions within the Newala Limestone 

during the late middle to early late Whiterockian in the area 

that is now central Alabama. About 30 to 40 km northeast 

of Pratt Ferry and east of the Helena fault, the Odenville 

Limestone conformably overlies the Newala Limestone. 

Conodonts from the Odenville (J.E. Repetski, U.S. Geological Survey, unpub. data) indicate a very latest Early 

Ordovician age (highest 0. communis Zone) to possibly 

very earliest Whiterockian age. This suggests that the 

depression at Pratt Ferry formed during early or middle 

Whiterockian time. 

CONCLUSIONS 

At Pratt Ferry, Ala. , the base of the Lenoir Limestone 

consists of argillaceous dolostone and conglomerate. 

lithostratigraphy and Conodont Biostratigraphy at Pratt Ferry, Central Alabama C11 
Because these rocks are unlike other rocks in the Lenoir, 

they are herein designated the Cottingham Creek Member 

of the Lenoir Limestone. Conodonts indicate that this new 

member is of late middle to early late Whiterockian age and 

disconformably overlies the Newala Limestone. At this 

locality, the Newala Limestone is of late Early Ordovician 

age. The contact of the Cottingham Creek Member and the 

overlying Mosheim Member of the Lenoir Limestone is 

sharp and irregular and represents a discontinuity surface of 

relatively short duration. The Cottingham Creek deposits 

occur in paleokarst depressions developed on the Newala 

during the early and (or) middle Whiterockian. Areal 

distribution and lithostratigraphic and biostratigraphic data 

prove conclusively that the Cottingham Creek Member is 

geographically, lithologically, and chronologically distinct 

from the Attalla Chert Conglomerate Member. The Cottingham Creek is correlative with the Douglas Lake Member of 

the Lenoir Limestone of northeastern Tennessee, at least the 

lowest beds of the Wells Creek Dolomite of south-central 

Tennessee, and only the lower part, apparently, of the Pond 

Spring Formation of northwestern Georgia. 

REFERENCES CITED 

Bentall, Ray, and Collins, J.B., 1945, Subsurface stratigraphy and 

structure of the pre-Trenton Ordovician and Upper Cambrian 

rocks in central Tennessee: Tennessee Division of Geology 

Oil and Gas Investigations Preliminary Chart 4. 

Bergstrom, S.M., 1971, Conodont biostratigraphy of the Middle 

and Upper Ordovician of Europe and eastern North America, 

in Sweet, W.C., and Bergstrom, S.M., eds., Symposium on 

conodont biostratigraphy: Geological Society of America 

Memoir 127, p. 83-161. 

---1983, Biogeography, evolutionary relationships, and biostratigraphic significance of Ordovician platform conodonts: 

Fossils and Strata, no. 15, p. 35-58. 

Bridge, Josiah, 1955, Disconformity between Lower and Middle 

Ordovician Series at Douglas Lake, Tennessee: Geological 

Society of America Bulletin, v. 66, p. 725-730. 

Brink, A.B., 1984, A brief review of the South African sinkhole 

problem, in Beck, B.F., ed., Sinkholes: Their geology, 

engineering, and environmental impact: Rotterdam, Netherlands, A.A. Balkema Publishers, p. 79-87. 

Broadhead, T. W., Harris, C. S. , and Repetski, J. E., in press, 

Taphonomy of Middle Ordovician conodonts from peritidal 

carbonate rocks of the southern Appalachians and midcontinent of North America: Geological Society of America 

Bulletin. 

Butts, Charles, 1926, The Paleozoic rocks, in Adams, G.I., and 

others, Geology of Alabama: Geological Survey of Alabama 

Special Report no. 14, p. 41-230. 

Cooper, G.A., 1956, Chazyan and related brachiopods: Smithsonian Miscellaneous Collections 127 (2 parts), 1,024 p. 

Decker, C.E., 1952, Stratigraphic significance of graptolites of 

Athens Shale: American Association of Petroleum Geologists 

Bulletin, v. 36, p. 1-145. 

C12 Shorter Contributions to Paleontology and Stratigraphy 

Drahovzal, J. A., 197 4, Lineaments of northern Alabama and 

possible regional implications, in Proceedings of the First 

International Conference on the New Basement Tectonics: 

Utah Geological Association Publication no. 5, p. 250-262. 

Drahovzal, J. A. , and Neathery, T. L., 1971, Middle and Upper 

Ordovician stratigraphy of the Alabama Appalachians, in 

Drahovzal, J. A. , and Neathery, T. L. , eds. , The Middle and 

Upper Ordovician of the Alabama Appalachians, a guidebook 

for the ninth annual field trip of the Alabama Geological 

Society: Tuscaloosa, Alabama, Alabama Geological Society, 

p. 1-62. 

Drahovzal, J.A., Neathery, T.L., and Wielchowsky, C.C. , 1974, 

Significance of selected lineaments in Alabama, in Third 

earth resources technology satellite-! symposium: National 

Aeronautics and Space Administration SP-351, v. 1, p. 

897-918. 

Ethington, R. L., and Clark, D. L., 1981, Lower and Middle 

Ordovician conodonts from the Ibex area western Millard 

County, Utah: Brigham Young University Geology Studies, 

v. 28' pt. 2, 160 p. 

Finney, S.C., 1977, Graptolites of the Middle Ordovician Athens 

Shale, Alabama: Columbus, Ohio, Ohio State University, 

Ph.D. thesis, 585 p. 

---1984, Biogeography of Ordovician graptolites in the southern Appalachians, in Bruton, D.L. , ed., Aspects of the 

Ordovician System: Palaeontological Contributions from the 

University of Oslo, no. 295, p. 167-176. 

Hall, J.C., Bergstrom, S.M., and Schmidt, M.A., 1986, Conodont biostratigraphy of the Middle Ordovician Chickamauga 

Group and related strata of the Alabama Appalachians, in 

Benson, D.J., and Stock, C.W., eds., Guidebook for the 23d 

annual field trip of the Alabama Geological Society: Tuscaloosa, Alabama, Alabama Geological Society, p. 61- 81. 

Harris, C.S., 1982, Biostratigraphy and environmental distribution of conodonts from the lowermost Middle Ordovician in 

east Tennessee: Knoxville, Tennessee, University of Tennessee, M.S. thesis, 160 p. 

LaMoreaux, P.E. , 1984, Catastrophic subsidence: Shelby County, 

Alabama, in Beck, B.F., ed., Sinkholes: Their geology, 

engineering, and environmental impact: Rotterdam, Netherlands, A.A. Balkema Publishers, p. 131- 137. 

Laurence, R.A., 1944, An Early Ordovician sinkhole deposit of 

volcanic ash and fossiliferous sediments in east Tennessee: 

Journal of Geology, v. 52, no. 4, p. 235-249. 

Milici, R.C., and Smith, J.W., 1969, Stratigraphy of the Chickamauga Supergroup in its type area, in Georgia Geological 

Survey, Precambrian-Paleozoic Appalachian problems: 

Georgia Geological Survey Bulletin 80, p. 1- 55. 

Neathery, T.L., and Drahovzal, J.A., 1971, Stop 3: Hensley 

Mountain section (Attalla Chert Conglomerate- post-Knox 

unconformity), in Drahovzal, J .A., and Neathery, T.L., 

eds., The Middle and Upper Ordovician of the Alabama 

Appalachians, a guidebook for the ninth annual field trip of 

the Alabama Geological Society: Tuscaloosa, Alabama, Alabama Geological Society, p. 185- 188. 

---1986, Middle and Upper Ordovician stratigraphy of the 

southernmost Appalachians, in Neathery, T.L., ed., Centennial Field Guide, v. 6, Southeastern section of the Geological 

Society of America: Boulder, Colorado, Geological Society 

of America, p. 167-172. 
Repetski, J.E., 1982a, Conodonts from El Paso Group (Lower 

Ordovician) of westernmost Texas and southern New Mexico: New Mexico Bureau of Mines and Mineral Resources 

Memoir 40, 121 p. 

---1982b, Magnitude of the post-Knox unconformity (Lower/ 

Middle Ordovician) in the central basin of Tennessee, as 

measured by conodonts: Geological Society of America 

Abstracts with Programs, v. 14, nos. 1 and 2, p. 76. 

---1985, Conodont biostratigraphy of the Knox Group at the 

Thorn Hill and River Ridge sections, northeastern Tennessee, 

in Walker, K. R., ed. , The geologic history of the Thorn Hill 

Paleozoic section (Cambrian-Mississippian), eastern Tennessee: University of Tennessee, Department of Geological 

Sciences Studies in Geology 10, p. 25- 31. 

Repetski, J.E., and Harris, A.G., 1986, Conodont biostratigraphy 

and biofacies of Upper Knox/Beekmantown Groups and 

overlying Ordovician rocks in the Appalachian basin, New 

York to Alabama [abs.]: American Association of Petroleum 

Geologists Bulletin, v. 70, p. 637-638. 

Roberson, K.E., 1988, The post-Knox unconformity and its 

relationship to bounding stratigraphy, Alabama Appalachians: Tuscaloosa, Alabama, University of Alabama, M.S. 

thesis, 148 p. 

Ross, R.J., Jr., and others, 1982, The Ordovician System in the 

United States: International Union of Geological Sciences 

Publication no. 12, 71 p. 

Ruedemann, Rudolf, 194 7, Graptolites of North America: Geological Society of America Memoir 19, 652 p. 

Schmidt, M.A., 1982, Conodont biostratigraphy and facies relations of the Chickamauga Limestone (Middle Ordovician) of 

the southern Appalachians, Alabama and Georgia: Columbus, Ohio, Ohio State University, M.S. thesis, 270 p. 

Shaw, T. H., 1987, Lithostratigraphy and conodont biostratigraphy of the Newala Limestone in its type area, south-central 

Alabama: Atlanta, Georgia, Emory University, M.S. thesis, 

550 p. 

Sweet, W.C., 1984, Graphic correlation of upper Middle and 

Upper Ordovician rocks, North American Midcontinent 

Province, U.S.A., in Bruton, D.L., ed., Aspects of the 

Ordovician System: Palaeontological Contributions from the 

University of Oslo, no. 295, p. 23-35. 

Sweet, W.C., and Bergstrom, S.M., 1962, Conodonts from the 

Pratt Ferry Formation (Middle Ordovician) of Alabama: 

Journal of Paleontology, v. 36, no. 6, p. 1214-1252. 

Votaw, R.B., 1971, Conodont biostratigraphy of the Black River 

Group (Middle Ordovician) and equivalent rocks of the 

eastern Midcontinent, North America: Columbus, Ohio, 

Ohio State University, Ph.D. thesis, 170 p. 

lithostratigraphy and Conodont Biostratigraphy at Pratt Ferry, Central Alabama C13 

PLATE 1 

[SEM photomicrographs of specimens coated with carbon and gold; all specimens reposited 

in the U.S. National Museum of Natural History (USNM), Washington, D.C.] 

Contact photographs of the plates in this report are available, at cost, from the U.S. Geological Survey 

Photographic Library, Federal Center, Denver, CO 80225. 
PLATE 1 

Selected conodonts from below and above the Lower-Middle Ordovician disconformity at Pratt Ferry, 

central Alabama 

Figures 1-13. Conodonts from the Mosheim Member of the Lenoir Limestone. 

1. Cahabagnathus friendsvillensis (Bergstrom), upper view of pastiniplanate 

element, X75, USGS colln. 10088- CO, USNM 430386. 

2-4. Phragmodus flexuosus Moskalenko, lateral views of M, P (outer), and Sc 

elements, X75, USGS colln. 10091-CO, USNM 430387-89. 

5-7. Ansella nevadensis (Ethington and Schumacher), lateral views of P, M, 

and Sa elements, X50, USGS colln. 10086-CO, USNM 430390-92. 

8, 9. Belodina monitorensis Ethington and Schumacher, inner lateral views of 

oistodontiform and rastrate elements, x75, USGS colln. 10091-CO, 

USNM 430393- 94. 

10-12. Erraticodon aff. E. balticus Dzik, x 50. 

10. Anterior view of Pb element, USGS colln. 10091-CO, USNM 

430395. 

II, 12. Inner lateral views of M and Sc (anterolateral process broken) 

elements, USGS colln. 10088- CO, USNM 430396-97 . 

13. Leptochirognathus quadratus Branson and Mehl, inner lateral view of 

primadontiform element, X75, USGS colln. 10086- CO, USNM 430398. 

14-16. Plectodina joachimensis (Andrews), X75. 

14, 16. Inner lateral views of Pa and Sc elements, Mosheim Member of Lenoir 

Limestone, USGS colln. 10086- CO, USNM 430399, 410816. 

15. Posterior view of Sb element, Cottingham Creek Member of Lenoir Limestone, USGS colln. 10046-CO, USNM 410817. 

17. Panderodus sp., outer lateral view, x 7 5, Cottingham Creek Member of Lenoir 

Limestone, USGS colln. 10083- CO, USNM 430400. 

18- 23. Conodonts from the upper part of the Newala Limestone. 

18, 19. Diaphorodus delicatus (Branson and Mehl), inner lateral views of M and 

Sb elements, x75, USGS colln. 10039-CO, USNM 430401- 02. 

20. Oneotodus costatus Ethington and Brand, inner lateral view (anterobasal 

margin partly broken), X75, USGS colln. 10080- CO, USNM 430403. 

21. Cristodus loxoides Repetski, inner lateral view of rastrate element, X75, 

USGS colln. 10082-CO, USNM 430404. 

22. Drepanodus concavus (Branson and Mehl), inner lateral view of arcuatiform element, X75, USGS colln. 10033- CO, USNM 430405. 

23 . "Scolopodus" emarginatus Barnes and Tuke, inner posterolateral view of 

Sb? element, X75, USGS colln. 10080- CO, USNM 430406. 
U.S. GEOLOGICAL SURVEY BULLETIN 1895-C PLATE 1 

CAHABAGNATHUS, PHRAGMODUS, ANSELLA, BELODINA, ERRATICODON, LEPTOCHIROGNATHUS, PLECTODINA, 

PANDERODUS, DIAPHORODUS, ONEOTODUS, CRISTODUS, DREPANODUS, AND "SCOLOPODUS" 

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