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Chainman Shale, West-Central Utah

U.&. SUEVEY PROFESSIONAL FAFER 1368
Late Mississippian Gastropods of the 

Chainman Shale, West-Central Utah

By MACKENZIE GORDON, JR., and ELLIS L. YOCHELSON

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 136

Descriptions, geographic and stratigraphic distribution, and 

illustrations of 79 species of gastropods in eight assemblages, which 

are equated with established ammonoid and foraminiferal zones

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1987
DEPARTMENT OF THE INTERIOR 

DONALD PAUL MODEL, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Library of Congress Cataloging-in-Publication Data

Gordon, Mackenzie, 1913-

Late Mississippian gastropods of the Chainman Shale, west-central Utah.

(U.S. Geological Survey professional paper ; 1368)

Bibliography: p. 104

Supt. of Docs, no.: I. 19.16:1368

1. Gasteropoda, Fossil. 2. Paleontology Mississippian. 3. Shale Utah. I. Yochelson, Ellis Leon, 1928- . II. Title.

III. Series:

Geological Survey professional paper ; 1368. 

QE808.G68 1987 564'.3 85-600024

For sale by the Books and Open-File Reports Section, U.S. Geological Survey, 

Federal Center, Box 25425, Denver, CO 80225
CONTENTS

Abstract ..................

Introduction ..............

Acknowledgments .....

Previous work ............

Meramecian gastropods 

Idaho ...............

Nevada .............

Arizona .............

Chesterian gastropods . 

Utah ...............

Nevada .............

................ 1

2 

........................... 2

3

........................... 3

........................... 3

........................... 4

	4 

........................... 5

	5 

	5 

Wyoming .......................................... 5

Montana ........................................... 6

Present investigation ..................................... 6

Type and type lot .................................... 7

Data on occurrence ................................... 7

Composition of the fauna ................................. 7

Distribution of gastropods in the study area .-...-.....--... 8

Granite Mountain section ............................. 8

Area northeast of Foote Range ............--..--.---.. 12

Foote Ranch partial section ........................... 12

Bishop Springs anticline .............................. 14

Indian Pass area .-..--..--..--.-----------..--..----- 15

Skunk Spring section .....-...-...-..---...-..-..---.. 15

Southern part of Camp Canyon ........................ 17

Brown's Wash-Wallet Gulch partial section ............ 17

Distribution of gastropods in the study area Continued

Conger Spring area __.._....._...---.-----._...-..--.

Area south of Conger Mountain ......................

Coyote Pass area .-...-.---.--.-.---.-----.--..-...-.

Jensen Wash section ..............-..--..--.--.--...

Southern slope of Burbank Hills .......--..--.---.-...

Western part of Burbank Hills .......................

Northern end of Needle Range .......................

Gastropod assemblages and their relationship to ammonoid 

and foraminiferal zones ..........................

Gastropods as guide fossils ...............--..--.-.----.-.

Diversity and facies control ..............--.-.-.---......

Systematic paleontology .................................

Bellerophontacea .............-..--..--.--.--..--....

Pleurotomariacea ...............--..--.---.---..-...

Murchisoniacea ......................--.---.-----...

Euomphalacea .......-...-.---.-..-..-..-------.---.

Platyceratacea ...-...-......------.--..-.---.--..--.

Microdomatacea ......................-..---.--..-.-.

Neritacea ...............--.---.---.--..-.--..--..--.

Loxonematacea .....................................

Subulitacea .................--..--.---.--..-..--..-.

Opisthobranchia .._.........--..--..--.--..--.--..-.

Register of localities .....................................

References ..............................................

Index 

18

19

19

19

21

21

21

21

26

26

26

27

45

79

82

85

87

87

90

94

98

99

104

107

ILLUSTRATIONS

[Plates follow index]

PLATE 1. Sinuitina, Bellerophon, Euphemites.

2. Euphemites, Retispira.

3. Straparollus, Trepospira, Ptychomphalina.

4. Lunulazona, Euconospira, Ptychomphalina, Mourlonia.

5. Glabrocingulum.

6. Glabrocingulum.

7. Worthenia, Glabrocingulum, Deseretospira, Cinclidonema, Catazona, Neilsonia, Bayleat, Dictyotomaria?

8. Platyceras, Anematina, Strophostylus, Naticopsis, Straparollus, lanthinopsis.

9. Pseudozygopleura, Bulimorpha, Meekospira?, Meekospira, Bellazona, Stegocoelia,lanthinopsis?, lanthinopsis, Girtyspira, 

Soleniscus, Loxonema?, Loxonema.

FIGURE 1. Index map of western Utah, showing location of 15-minute quadrangles that contain the Confusion Range and adjacent 

areas referred to in the text ............................................................................

2. Part of the Granite Mountain 15-minute quadrangle, showing the position of Granite Mountain measured section ...

3. Part of the Gandy 15-minute quadrangle, showing the position of the Foote Ranch measured section ................

4. Part of the Cowboy Pass 15-minute quadrangle, showing the position of the Skunk Spring measured section .........

5. Part of the Conger Mountain 15-minute quadrangle, showing the position of the Brown's Wash-Wallet Gulch measured 

section ...............................................................................................

6. Part of the Burbank Hills 15-minute quadrangle, showing the position of the Jensen Wash measured section ........

Page

9

10

13

16

18

19

m
IV CONTENTS

TABLES

Page

TABLE 1. Taxonomic relationships and relative abundance of gastropods in the Chainman Shale ............................. 8

2. Biostratigraphic distribution of bellerophontaceans in the Chainman Shale ........................................ 22

3. Biostratigraphic distribution of common pleurotomariaceans in the Chainman Shale ............................... 22

4. Biostratigraphic distribution of other pleurotomariaceans, euomphalaceans, neritaceans, and species from other superfamilies in the Chainman Shale ............_............................................-...-.......... 23
LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE,

WEST-CENTRAL UTAH

By MACKENZIE GORDON, Jr., and ELLIS L. YOCHELSON

ABSTRACT

The Chainman Shale of Mississippian (Osagean to late Chesterian) age, well exposed in the Confusion Range of western Utah, has 

yielded a profusion of fossils during investigations conducted by the 

U.S. Geological Survey in the past 30 years. Conspicuous among 

these fossils are gastropods, which range in age from latest Meramecian to late Chesterian. In west-central Utah, not far from the State 

boundary, the Chainman outcrop belt stretches from Granite Mountain south to the northern part of the Needle Range, a distance of 69 

miles (110 km). The Chainman thickens from north to south; the 

section at Granite Mountain is 1,315 feet (401 m) thick and that at 

Jensen Wash in the Burbank Hills, 2,203 feet (671 m).

The rocks of the Chainman Shale record a general though irregular shallowing of the area from moderate depths of 330 feet (100 m) 

or so to quite shallow depths of perhaps locally little more than 3-6 

feet (1-2 m). Most of the gastropods occur with ammonoids in a facies 

of shale or shale containing phosphatic limestone concretions. In this 

lutaceous facies, Glabrocingulum is predominant and Lunulazona 

and Retispira are common; these genera are represented by a succession of species. A thick limestone unit is present in some areas in the 

upper part of the formation, particularly in the vicinity of Skunk 

Spring, where it is 318 feet (97 m) thick. This limestone unit represents a calcareous shoal facies having an entirely different gastropod 

fauna, characterized by Catazona and species of Naticopsis.

The Chainman Shale could be easily zoned by gastropods, but we 

are not proposing such a zonation. A framework of ammonoid and 

foraminiferal zones already is available, and we prefer to regard the 

gastropod assemblages as part of this framework. The assemblages 

are confined to the major ammonoid and foraminiferal zones, and 

only three of the gastropod species seem to range across major zonal 

boundaries. These species are Bellerophon (Bellerophon) vespertinus 

Gordon and Yochelson and Straparollus (Euomphalus) intermedius 

Gordon and Yochelson, both of which are present in Mamet 

Foraminifer Zones 17 and 18, and Bellazona polita n. sp., which 

locally seems to range from Mamet Foraminifer Zone 16s into the 

basal part of Zone 17.

Eight assemblages, seven of them in ascending stratigraphic order, 

are recognized within the gastropod fauna of the Chainman Shale; 

the eighth assemblage is a facies equivalent of the sixth highest. The 

seven mud-dwelling assemblages are characterized mainly by species of Glabrocingulum and Lunulazona, which together account for 

80 percent of the gastropod specimens in our Chainman collections. 

The eighth assemblage, that in the shallow-water carbonate facies, is 

the one characterized by Catazona and species of Naticopsis.

The lowermost gastropod assemblage, that of Lunulazona nodomarginata (McChesney), includes 10 species and is restricted to the

northern end of the study area, where it occurs in the upper part of 

the Goniatites americanus Ammonoid Zone, in beds equivalent to the 

lower part of Mamet's Foraminifer Zone 16i. We regard the entire G. 

americanus Zone as late Meramecian in age. All the zones higher in 

the Chainman are Chesterian in age. The second assemblage is that 

of Lunulazona costata Sadlick and Neilsen, which includes six gastropod species; it occurs in the Goniatites granosus Ammonoid Zone, 

equivalent to Mamet's Foraminifer Zone 16s.

Three gastropod assemblages are recognized within the 

Paracravenoceras barnettense Ammonoid Zone, equivalent to 

Mamet's Foraminifer Zone 17. The earliest, that of Lunulazona 

sadlicki, includes five species; the intermediate, that of Glabrocingulum hosei n. sp., four species; and the highest, that of Glabrocingulum confusionense n. sp., two species (the second being G. hosei).

Two laterally equivalent facies-controlled assemblages are present 

within the Cravenoceras hesperium Ammonoid Zone, most of which 

is equivalent to Mamet's Foraminifer Zone 18. The Glabrocingulum 

quadrigatum Sadlick and Neilsen assemblage, restricted to shale, 

includes 21 species. The equivalent assemblage, that of Catazona 

rudilirata Gordon and Yochelson, noted above, occurs in mediumgrained gray limestone, associated with brachiopods. Glabrocingulum and Lunulazona are absent, and several species of Naticopsis are 

present among 18 species of gastropods; only two of these species are 

known to occur in the equivalent shale assemblage.

Finally, in Mamet's Foraminifer Zone 19, partly in limestone beds 

containing the ammonoid Richardsonites merriami (Youngquist) and 

in shale containing the productoid brachiopod Carlinia phillipsi 

(Norwood and Pratten), is a faunule totaling 19 species, eight of 

which are also found in the Cravenoceras hesperium Ammonoid Zone. 

In the basal part of the overlying Ely Limestone (Mississippian, 

Mamet Foraminifer Zone 19), gastropods are absent. At Granite 

Mountain, where this part of the sequence has been studied in detail, 

it consists of 140 feet (42.7 m) of coarse-grained limestone and some 

interbedded shale and sandstone.

The distribution of Chainman gastropods shows that speciation in 

many groups was as rapid as that in the ammonoids, perhaps in some 

groups even more rapid. For this reason, the gastropods are very 

useful at the species level as guide fossils. However, the susceptibility of gastropods to facies changes is greater than that of the ammonoids. Hence, gastropods must be used with caution, particularly 

where long-distance correlation is attempted.

Because of the large number of taxa present in the Chainman 

Shale, our investigation has provided the opportunity to reexamine 

some of the older studies of Mississippian gastropods in the United 

States and to reassess the generic assignment of many species. For 

each genus considered herein, a listing is given of the North American species judged to belong in that taxon. Although the arrange1
LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

ment of genera and families is more or less traditional, some suborders have been rearranged in accordance with current views on 

systematics.

Most of this work is concerned with systematic description and 

illustration. Thirty-seven genera and subgenera belonging in 17 

families occur in the Chainman fauna. Seventy-nine species are recognized in the study area. Of these, 13 have been previously described and 32 are named as new; 5 more are closely comparable with 

previously described species. The other 29 species are indicated by 

open nomenclature.

Two new genera are proposed in this paper: Deseretospira (type 

species, D. monilifera n. sp.) and Bellazona (type species, Loxonema 

bella Walcott, 1882); also one new subgenus: Sinuitina (Vorticina) 

(type species, Sinuitina anneae Conkin, 1957). Two new tribes are 

recognized: Deseretospirides (to include Deseretospira, Wellergyi, 

and Platyteichum) and Glabrocingulides (to include Glabrocingulum 

and Eirlysia).

New species described in this paper are: Sinuitina (Sinuitina) 

crispa, S. (Vorticina) vortex, Euphemites cracens, Bellerophon 

(Bellerophon) needlensis, B. (B.) welshi, Retispira cincta, R. ordinata, 

R. jensenensis, R. stenopsis, Trepospira (Angyomphalus) regularis, 

T. (Trepospira) baconi, T. (T.) diadema, Mourlonia venusta, 

Ptychomphalina burbankensis, Deseretospira monilifera, Glabrocingulum (Glabrocingulum) granulosum, G. (G.) mephitifontis, G. (G.) 

confusionense, G. (Glabrocingulum?) hosei, Lunulazona sadlicki, L. 

utahensis, Euconospira desereti, E. gradilis, Bellazona polita, Straparollus (Euomphalus) nodibasis, Naticopsis (Naticopsis) confusionensis, N. (Naticopsis?) clinovata, Pseudozygopleura (Pseudozygopleura) repenningi, P. (Pseudozygopleura?) lauta, P. (Stephanozyga) 

claviger, lanthinopsis gandyensis, and Girtyspira circumsecta. A new 

name, Retispira eliasi, is proposed to replace Bucanopsis (Retispira?) 

reticulata Elias, 1958 [not Bellerophon reticulatus M'Coy, 1844], both 

of which belong in Retispira. A lectotype is designated for Glabrocingulum (Ananias) nevadense (Walcott), of late Meramecian age, from 

the Diamond Peak Formation of Nevada, and this species is figured 

by photographs for the first time.

INTRODUCTION

Monographic studies of western American Carboniferous gastropod faunas are practically nonexistent. In 

our previous effort to document the gastropods of the 

Amsden Formation of Wyoming (Gordon and 

Yochelson, 1975), the preservation of the specimens 

was such that we had to adopt an open nomenclature 

for all but three of the species; our study of gastropods 

from the Diamond Peak Formation of Nevada (Gordon 

and Yochelson, 1983) was limited to specimens from a 

single bed. Therefore, to be able to study the association and distribution patterns of a relatively large 

number of well-preserved gastropods through the thick 

Chainman Shale succession has been a source of satisfaction. We find that the gastropods are biostratigraphically diagnostic and are facies indicators.

The study area in west-central Utah, in which Mississippian and Pennsylvanian strata crop out in a belt 

that stretches for more than 66 miles (110 km), has 

provided a large number of well-preserved fossils of 

many groups. During the past 30 years, the extensive

collections made from this area have, in addition to 

gastropods, included corals, sponges, bryozoans, brachiopods, pelecypods, cephalopods, pelmatozoans, 

arthropods, foraminifers, and conodonts. Because deposition was essentially continuous in this region 

through much of the Late Mississippian and Early and 

Middle Pennsylvanian, this outcrop belt has proved to 

be a particularly advantageous laboratory in which to 

study the sequence of faunas, particularly those extending across the Mississippian-Pennsylvanian 

boundary.

The gastropods upon which this study is based range 

in age from late Meramecian to late Chesterian. Eight 

gastropod assemblages are recognized, of which seven 

are in ascending sequence, the eighth being a facies 

equivalent of the sixth highest. These assemblages are 

equated with the sequence of ammonoid zones described by Gordon (1970, p. 821-822) from the same 

region. We do not propose a series of gastropod zones; 

the gastropod species have relatively short stratigraphic ranges similar to those of the ammonoid species and can be tied conveniently to the named ammonoid zones.

ACKNOWLEDGMENTS

The studies upon which this report is based began in 

support of the field mapping program of the U.S. Geological Survey (USGS) in this area, under the direction 

of Richard K. Hose. Hose and his associates provided 

several early collections that gave some inkling of the 

richness of the Chainman fauna. In 1957, Hose and 

Charles A. Repenning, USGS, measured selected sections with Gordon and helped obtain additional collections. Walter Sadlick, formerly of the University of Illinois at Chicago, pointed out valuable reference sections 

in the Burbank Hills and Needle Range. Also, John E. 

Welsh, formerly of Kennecott Copper Corporation, contributed a large fossil collection from the Burbank 

Hills. As the work progressed, Keith R. Moore, USGS, 

assisted in the field for several seasons, and Rudolph 

W. Kopf, Reed Christner, Richard Rieke, William E. 

McCaslin, and Charles E. Mason, all USGS, assisted 

for one season each. Photographs for this report were 

taken by Robert H. McKinney and Haruo E. 

Mochizuki, USGS.

Examination of comparative material from collections other than those of the U.S. National Museum 

(USNM) and the USGS was necessary. Matthew H. 

Nitecki, Field Museum of Natural History, Chicago, 

111., and Roger L. Batten, American Museum of Natural 

History, New York City, generously provided, for our 

examination, specimens that were in their care. P. K. 

Sutherland, Stovall Museum, University of Oklahoma,
PREVIOUS WORK

Norman, made available to us some of the material 

described by Elias from the Redoak Hollow Formation. 

We also were able to examine types of related species at 

the British Museum (Natural History) thanks to H. W. 

Ball, Keeper of Palaeontology, and to Noel Morris. To 

all those who have helped us in our study of the Chainman gastropod fauna, we are deeply grateful.

PREVIOUS WORK

During the past 100 years, only nine papers have 

been published describing Late Mississippian gastropods from the Cordilleran geosyncline in the Western United States. In these papers, a total of 18 species 

from beds of Meramecian age and 23 from beds of Chesterian age were described and named. The number of 

papers describing Late Mississippian gastropods from 

the Midcontinent and Appalachian regions is much 

greater; consequently, the number of species named 

from these regions is also much larger. One of the more 

recent and comprehensive of these works is that by 

Thein and Nitecki (1974) on Chesterian Gastropoda of 

the Illinois basin. The bibliographic index by 

Yochelson and Saunders (1967) includes all the late 

Paleozoic species described in North America through 

the year 1966.

The following discussion deals with the gastropods 

from rocks of Late Mississippian (Meramecian and 

Chesterian) age in each of the Western States.

MERAMECIAN GASTROPODS

IDAHO

The earliest record of Late Mississippian gastropods 

in the far West is from rocks of late Meramecian age in 

southeastern Idaho. These gastropods were reported 

more than 100 years ago by Meek (1873, p. 433), who 

listed a small fauna of fossil invertebrates collected by 

F. H. Bradley on the divide between Ross Fork and 

Lincoln Valley. That Meek's report cited the locality as 

being in Montana is not surprising, because Idaho did 

not become a state until 18 years after the collection 

was made. The Ross Fork-Lincoln Valley divide now 

lies in the Fort Hall Indian Reservation, Idaho, roughly 

100 miles (160k) south of the Idaho-Montana State 

line. The fossils listed by Meek included small mollusks, among which were the following gastropods: 

Bellerophon (2 spp.), Euomphalus spergenensis Hall, 

Pleurotomaria sp., Holopea sp., and Platyceras spp. 

Much of this collection is still preserved at the U.S. 

National Museum, but the gastropods have been removed and could not be found. Meek pointed out that 

this assemblage bears a remarkable resemblance to

that found at Spergen Hill, Ind., which is now included 

in the Salem Limestone. The USGS uses the earlier 

name Salem Limestone (Cumings, 1901, p. 233), which 

has priority over the name Spergen Limestone (Ulrich, 

1904, p. 110).

Rocks containing the fauna listed by Meek were assigned by Mansfield (1920, p. 35, 36) to the Brazer 

Limestone. Later studies by Sando, Dutro, and Gere 

(1959) showed that this assignment was incorrect, because the type Brazer is an equivalent of the Mission 

Canyon Limestone of Montana and does not contain 

beds as young as those containing the supposed Salem 

fauna. According to Mansfield (1920, p. 36), G. H. Girty 

unsuccessfully attempted to find Meek's locality and 

concluded that the locality data were inadequate and 

that the fossils probably were collected outside the Ross 

Fork drainage basin and outside the limits of the Fort 

Hall Reservation. However, Mansfield's geologic map 

shows two patches of Brazer Limestone in the vicinity 

of the Ross Fork-Lincoln Valley divide (Sando, 1965, p. 

E13), and the report of Bradley (1872), who made the 

collection, is fairly explicit about where it was made.

The corals from Meek's collection were studied by 

Sando (1965, p. E13), who assigned them to iheFaberophyllum Zone, which occupies the lower half of the 

Monroe Canyon Limestone of the Chesterfield Range 

Group. The Faberophyllum Zone is widespread in the 

Cordilleran geosyncline and is late Meramecian (Late 

Mississippian) in age.

G. H. Girty (in Mansfield, 1927, p. 66-71, 426-432, 

pi. 25) described several gastropods from a similar 

Salem-like fauna in southeastern Idaho; he considered 

this fauna equivalent to that listed by Meek. Girty's 

fossils came from several localities in the Henry, Montpelier, and Slug Creek quadrangles, Idaho. His species, 

most of which were reassigned to other genera by Thein 

and Nitecki (1974), include the following:

Straparollus (Euomphalus) tricarinatus (Girty) 

Rhineoderma pealeanum (Girty) 

R. dinglense (Girty) 

Gosseletina aspeniana (Girty) 

Dictyotomaria brazeriana (Girty) 

Wellergyi brazerianus (Girty) 

Platyceras (Orthonychia) striatulum (Girty, including var. gracile (Girty) 

Bulimorpha elegans Girty

Associated with these gastropods are other species 

not described by Girty, which we have determined as 

belonging in the following genera and subgenera: Sinuitina*!, Euphemites, Bellerophon (Bellerophon), 

Retispira, Straparollus (Straparollus), Trepospira 

(Angyomphalus)?, Baylea?, Spiroscala, Portlockiella?, 

Euconospira, Glabrocingulum (Glabrocingulum)?,
LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Borestus, Amaurotoma, Yunnania, Platyceras (Platyceras), Anematina, Anomphalus, Naticopsis (Naticopsis), Murchisonia, Stegocoelia, Palaeostylus (Pseudozygopleura), lanthinopsis, Girtyspira, Meekospira, 

and Donaldina, as well as several additional species 

that probably belong in new genera. Although most of 

the gastropod species resemble those from the Salem 

Limestone of Indiana, most probably are new taxa.

Girty (in Mansfield, 1927, p. 69) stated that the 

southwestern Idaho fauna was a pre-Chester fauna 

having Spergen affinities, and he tentatively correlated it with the fauna of the Salem Limestone. Additional faunal evidence from Girty's collections, however, suggests a post-Salem age. The abundance and 

diversity of gastropods in this fauna and the general 

similarity at the generic level between the Idaho and 

Indiana assemblages probably led Girty to correlate 

this fauna with the Salem fauna. Several other Mississippian gastropod assemblages from oolitic limestone 

are now known that contain an abundance of small 

mollusks and brachiopods, but only the assemblage of 

the Salem Limestone had been described in Girty's 

time.

The greatest diversity and number of invertebrate 

species was recognized in USGS collection 3023-PC 

from 6 3/4 miles (10.8 km) northwest of Henry, Caribou 

County, Idaho. Girty (in Mansfield, 1927, p. 69, 70) 

listed approximately 150 species of fossils that he had 

identified in this collection. Perhaps the most diagnostic forms are those that he listed as Mesoblastus n. sp. 

and Productus brazerianus n. sp.?, which indicate a 

probable late Meramecian to early Chesterian age. The 

presence of many forms that resemble Meramecian 

species and the general absence of several typical Chesterian genera, such as the productid Diaphragmus, 

suggest a Meramecian age for this fauna.

The collection containing the second largest number 

of invertebrate species is USGS collection 7607A-PC, 

from the NW V4 SW 1/4 sec. 13, T. 10 S., R. 43 E., Bear 

Lake County, Idaho. Here the coral Faberophyllum was 

found in loose blocks. Many of the gastropod species are 

the same as those in USGS collection 3202-PC. The 

conclusion, therefore, seems reasonable that this 

Salem-like fauna in southeastern Idaho occupies a single biostratigraphic zone within the Faberophyllum 

coral zone and is late Meramecian in age. As noted, this 

zone is now placed within the Monroe Canyon Limestone.

Although the Monroe Canyon Limestone gastropod 

fauna may contain more than 50 species and is only 

slightly older than the oldest gastropod assemblage in 

the Chainman Shale of Utah, not a single species is 

common to the two faunas.

NEVADA

Several late Meramecian gastropods were described 

and illustrated by Walcott (1884, p. 256-260) from the 

Diamond Peak Formation in the Eureka district of Nevada. Most of them came from the vicinity of a small 

conical hill in Windfall Canyon, about 3 miles (4.8 km) 

southeast of Eureka. We have examined Walcott's 

specimens and reassigned many of them as follows: 

USGS colln. 651. Sandy to pebbly limestone in 

canyon on south side of conical hill. Collectors, 

C. D. Walcott and C. H. Haskell, 1882. 

Glabrocingulum (Ananias) nevadense (Walcott) 

Platyceras (Platyceras) piso Walcott 

P. (Orthonychia?) occidens Walcott 

Naticopsis (Naticopsis) inornata (Walcott) 

Bellazona bella (Walcott) 

Soleniscus? sp. 

USGS colln. 652. Western slope of Richmond

Mountain. Collector, C. D. Walcott, 1880. 

Metoptoma peroccidens Walcott 

USGS colln. 655. Calcareous sandstone and conglomerate on east side of conical hill, west foot 

of Spring Mountain. Collector, C. D. Walcott, 

1880.

Retispira textilis (Hall) 

Straparollus (Euomphalus) subrugosus Meek

and Worthen

Lunulazona nodomarginata (McChesney) 

USGS colln. 657. In canyon north of Pinto Peak. 

Collectors, C. H. Haskell and C. D. Walcott, 

1882.

Bellerophon (Bellerophon) majusculus Walcott 

We found two of these species, Lunulazonanodomarginata and Bellazona bella in the lower part of the 

Chainman Shale at Granite Mountain, Utah.

ARIZONA

Nothing has been written specifically on the occurrence of Late Mississippian gastropods in Arizona. 

Yochelson (1962, 1969) published on the gastropods 

from the Redwall Limestone, a formation that ranges 

in age from Early Mississippian (Kinderhookian) to 

Late Mississippian (Meramecian). The best preserved 

specimens were collected on top of the Jerome Hill section, from residual chert derived from the Mooney Falls 

Member and Horseshoe Mesa Members of the Redwall. 

The upper part of the Mooney Falls and all of the 

Horseshoe Mesa Member are Meramecian in age. The 

faunal chart of Redwall gastropods (Yochelson, 1969, 

p. 440, table 26), however, indicates that most of the 

specimens are from the Mooney Falls Member. Most of 

the named species described by Yochelson (1962) are 

typical Early Mississippian (Osagean) forms; those spe-
PREVIOUS WORK

cies that may have come from beds of Late Mississippian age cannot be distinguished.

CHESTERIAN GASTROPODS

UTAH

Sadlick and Nielsen (1963) described and figured 

some Late Mississippian pleutrotomariacean gastropods of the Chainman Shale from several localities 

in west-central Utah. Lunulazona costata Sadlick and 

Nielsen was described from the lower part of the formation on the basis of specimens collected in the foothills 

east of Granite Mountain, Juab County. Lunulazona 

sp. A [ = L. sadlicki n. sp.] came from beds of Chesterian age that they identified as Chainman Shale, 0.3 

miles (0.5 km) northeast of Leppy Peak, Elko County, 

Nev., near Wendover, Utah. Mourlonia sp. 

[ = Ptychomphalina sp. of this report] is from that locality.

Glabrocingulum binodosum Sadlick and Nielsen was 

based upon specimens collected near the top of the 

Chainman in the Foote Range, Millard County, Utah, 

and G. quadrigatum Sadlick and Nielsen, also from 

the upper part of the Chainman, was described from 

specimens collected on the northern slope of the Burbank Hills, Millard County. Sadlick and Nielsen included in G. quadrigatum specimens from the northern part of the Confusion Range, which we herein place 

in another species (Glabrocingulum (Glabrocingulum) 

confusionense n. sp.). They also described but did not 

figure Glabrocingulum. n. sp. aff. G. inflatum (Elias) 

(probably = G. (Ananias) seminudum Gordon and 

Yochelson), from near the top of the formation on the 

southern slope of the Burbank Hills. Finally, Sadlick 

and Nielsen cited the occurrence ofWorthenia tenuilineata Girty in the upper part of the Chainman. We 

herein assign this species to the subgenus W. (Yochelsonospira). Sadlick and Nielsen's paper covers approximately 10 percent of the gastropod fauna of the Chainman Shale described in this report.

NEVADA

The first late Chesterian gastropod was described 

from Nevada only relatively recently. Mount (1973) 

described and illustrated Straparollus (Euomphalus) 

pancakensis from the Adetognathus unicornis 

Conodont Zone in the Pancake Range in northern Nye 

County. The gastropod was found 20 feet (6 m) above 

the base of the Ely Limestone.

Gordon and Yochelson (1983) described a large 

faunule of gastropods from a single bed, about 1.7 ft 

(0.5 m) thick, in the upper part of the Diamond Peak

Formation at the northern end of the White Pine Range 

in White Pine County. This assemblage is associated 

with Cravenoceras hesperium , the name-bearer of the 

ammonoid zone of that name. This zone is Late Mississippian (late Chesterian) in age, though not latest Mississippian. More than half the species also occur in the 

Chainman Shale in west-central Utah; those that do 

are marked with an asterisk (*):

*Euphemites nevadensis Gordon and Yochelson

*Bellerophon (Bellerophon) vespertinus Gordon 

and Yochelson

*Retispira nolani Gordon and Yochelson

*R. albapinensis Gordon and Yochelson

*Straparollus (Euomphalus) intermedius Gordon

and Yochelson 

S. (E.) aff. S. (E.) pancakensis Mount

*S. (E.) n. sp. [ = S. (E.) nodibasis n. sp.]

*Trepospira (Trepospira) sp. [ = T. (T.) diadema n.

sp.] 

^Glabrocingulum (Ananias) seminudum Gordon

and Yochelson

*G. (Glabrocingulum) quadrigatum Sadlick and 

Nielsen

*Neilsonia cf. N. welleri Thein and Nitecki 

Hammatospira bellula Gordon and Yochelson

*Worthenia (Yochelsonospira) tenuilineata Girty

*Catazona rudilirata Gordon and Yochelson 

Compsonema fragile Gordon and Yochelson 

Platyceras (Orthonychia) sp.

*Strophostylus nevadensis Gordon and Yochelson 

S.? tantillus Gordon and Yochelson 

Microdoma sp.

Naticopsis (Naticopsis) glomerosa Gordon and 

Yochelson

*N. (N.?) n. sp. [ = N. (N.?) clinovata n. sp.l 

Turbonitella aff. T. biserialis (Phillips) 

Platyzona sp. 

Aclisina sp.

*Meekospira sp. 

Donaldina sp.

WYOMING

Late Chesterian gastropods were described from the 

Amsden Formation by Branson (1937) arid by Gordon 

and Yochelson (1975), along with Pennsylvanian forms 

from the same formation. The poor preservation of this 

material made it very difficult to determine species, 

and an open nomenclature was generally used. The 

gastropods included one form, identified as 

Bellerophonl sp. indet., from the Moffat Trail Limestone Member in Teton County and several from the 

Horseshoe Shale Member in Teton and Fremont Counties. The genera and subgenera recognized in the 

Horseshoe include: Euphemites, Bellerophon
6 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

(Bellerophon), Retispira, Straparollus (Euomphalus) , 

n. gen. aff. Colpites, Dictyotomaria, Gosseletina?, 

Worthenia?, Strophostylus, Naticopsis (Naticopsis), N. 

(Jedria?), Palaeostylus (Pseudozygopleura) lanthinopsis, Girtyspira, andDonaldina. Three species have been 

described and named from this fauna:

Euphemites sacqjawensis C. Branson 

Straparollus (Euomphalus) xylacus Gordon and 

Yochelson

Dictyotomaria carlbransoni Gordon and Yochelson 

One of the Wyoming forms, E. sacajawensis, occurs in 

the Chainman Shale of Utah.

MONTANA

Easton (1962, p. 98-101, pi. 13) described and figured several gastropods from rocks that he included in 

the Big Snowy Group in south-central Montana. We 

reexamined Easton's figured and unfigured specimens 

and offer the following revised identifications of the 

Late Mississippian (Chesterian) species. His paper 

gives details of the collecting localities.

From the Otter Formation in the measured section 

on Belt Creek, Cascade County (USGS colln. 14227- 

PC): Bellerophontacean, gen. and sp. indet.

From the Heath Formation (USGS colln. 13359-PC) 

and from overlying beds of Heath age, incorrectly attributed by Easton to the Cameron Creek Formation 

(now the Cameron Creek Member of the Tyler Formation) (see Sando, Gordon, and Dutro, 1975, p. A-51) in 

the measured section at Delpine, Meagher County 

(USGS collns. 13361-PC to 13363-PC):

Bellerophon (Bellerophon) sp.

Retispira? sp. indet.

Straparollus (Euomphalus) intermedius Gordon 

and Yochelson?

S. (E.) n. sp.

Trepospira (Angyomphalus) excavata (Easton)

Naticopsis (Naticopsis) sp.

Pseudozygopleura (Pseudozygopleura) sp.

P. (Stephanozyga) sp.

From the Heath Formation at localities in Fergus 

County (USGS collns. 13366-PC to 13368-PC, 13391- 

PC):

Euphemites sp.

Retispira cf. R. nolani Gordon and Yochelson

Straparollus (Euomphalus) intermedius Gordon

and Yochelson 

Naticopsis (Naticopsis) suturicompta Yochelson

and Dutro

From the Heath Formation in the measured section 

at Stonehouse Canyon, Golden Valley County (USGS 

collns. 13412-PC, 13414-PC):

Bellerophon (Bellerophon) sp.

Bellerophontacean, gen. and sp. indet.

Trepospira (Angyomphalus) excavata (Easton)

Glabrocingulum (Glabrocingulum) sp. indet.

Soleniscus spp.

Meekospira? sp. indet.

If those forms that are too poor to identify are eliminated, about 14 species constitute this Late Mississippian gastropod fauna. The straparollids and some of the 

bellerophontaceans are similar to Chainman species, 

but other elements of the Montana gastropod fauna are 

distinct.

PRESENT INVESTIGATION

The detailed work of the USGS in west-central Utah 

started in 1953, when R. K. Hose and his associates 

began mapping the geology of the Confusion Range. 

The first USGS collections that included gastropods 

were made that year. The writers visited the area in 

1954 and made additional collections. In 1957, Gordon 

spent a large part of the spring and fall field seasons 

working with Hose and C. A. Repenning, measuring 

sections and collecting fossils, mostly from the Chainman Shale. Mapping and collecting by Hose and others 

continued at least through 1962. Additional studies in 

this area were made by Gordon in 1961, 1962, 1969, 

1973 (with Yochelson), 1974, 1981, 1982, and 1983.

The early part of the work in this area focused particularly on the ammonoid succession, although fairly 

general collections of invertebrates were made. Some of 

the results of the cephalopod studies in this region have 

been published by Flower and Gordon (1959) and by 

Gordon (1970, 1971). The 1970 paper by Gordon was 

the one that proposed the ammonoid zonation for this 

region.

Geologic maps of parts of the Confusion Range showing outcrops of the Chainman Shale were published by 

Hose 1965a, b, 1974), by Hose and Repenning (1963, 

1964), and by Hose and Ziony (1963). A summary of the 

structural geology of the range was also prepared by 

Hose (1977).

In 1973, the writers began the description of the 

Chainman gastropods. A major digression resulted 

from our decision to publish descriptions of a wellpreserved gastropod faunule from the Diamond Peak 

Formation in the White Pine Range, Nev., before completing the Utah paper. The reason for this was that 

better preserved type lots of a few species were available in the Nevada material (see Gordon and Yochelson, 1983). The Utah study was taken up again late in 

1981 and completed in 1983. When we started this 

study, so little was known of the Late Mississippian 

gastropods in the United States and so many species
COMPOSITION OF THE FAUNA

had been assigned to the wrong genera that we found it 

necessary to reexamine many of the previously published species. The result is a paper of greater scope 

than had been intended originally.

Publication by Thein and Nitecki (1974) of a report 

on Chesterian gastropods from the Illinois basin gave a 

considerable boost to knowledge of the Chesterian 

fauna of the southern Midcontinent region. Along with 

the genera they described, they assigned and listed 

many of the previously described species. In their paper, Thein and Nitecki described and figured 75 species 

of Chesterian gastropods. If the 79 species described 

herein from the Late Mississippian of Utah, most of 

which are of Chesterian age and nearly all of which are 

different species than those occurring in Illinois, are 

added, one can begin to get an inkling of the diversity 

and complexity of the gastropod faunas in the United 

States during the latter part of the Mississippian Period.

TYPE AND TYPE LOT

As required by the International Code of Zoological 

Nomenclature, a holotype has been designated for each 

new species. Use of the term "paratype" varies considerably, some authorities holding this term to mean all 

specimens seen by the original author, apart from the 

holotype. However, a large number of specimens of 

some of the new species have been collected from many 

localities. Many of the specimens of the other new species are incomplete or worn and add nothing to the 

concept of the species. In general, we have restricted 

the term "paratype" to additional specimens from the 

locality that yielded the holotype. Commonly, more 

than one collection number is involved, because many 

of the better localities were collected several times. Occasionally, a figured paratype is from another locality, 

and additional specimens from that collection are designated as paratypes.

The term "hypotype" has no standing under the Code 

and is used in a variety of ways by authors. In our view, 

many specimens extend the known geographic or 

stratigraphic range of a previously described species 

but do not modify the interpretation of the taxonomic 

concept. To us, these are not hypotypes. Rarely, additional specimens do modify the concept presented by 

the original author; for such figured specimens, we use 

the term "hypotype."

DATA ON OCCURRENCE

Gastropods were obtained from 106 collections along 

the outcrop belt of the Chainman Shale. Each time a 

locality was visited, another collection number was assigned to the material. Thus, some localities have several collection numbers. Some collection numbers

listed under "Occurrence" in the descriptive section are 

preceded by a question mark. This mark indicates that 

the material is poorly preserved and that assignment to 

the particular taxon is in question; it does not question 

geographic position of the collection. Details of geologic 

and geographic occurrence are given in the "Register of 

Localities."

The occurrences of the various gastropod faunules 

are summarized in the following section. All known 

occurrences of the taxon in the region are listed again 

in the systematic section. Most of the collections contain one or more fossil groups in addition to the gastropods. We have not indicated this information except 

in the most cursory way. In addition, about 160 additional collections made in the area during the past 30 

years do not contain gastropods.

COMPOSITION OF THE FAUNA

Our study of the Chainman gastropods is based upon 

106 collections made in the study area during the 30 

years from 1953 to 1982. The gastropods occur in approximately 40 percent of the collections of invertebrate fossils made in this area. The 106 collections 

yielded 3,166 specimens of gastropods, which belong to 

79 species referrable to 37 genera and subgenera.

The gastropod fauna of the Chainman Shale is dominated overwhelmingly by the pleurotomariaceans, 

which constitute 88.6 percent of the Chainman Shale 

specimens under study. Two genera predominate 

Glabrocingulum , represented by nine species, and 

Lunulazona, by five species. The other superfamilies 

that compose this fauna are, in decreasing order of 

abundance, the bellerophontaceans (4.7 percent), 

murchisoniaceans (1.4 percent), neritaceans (1.3 percent), euomphalaceans (1.3 percent), subulitaceans (1.1 

percent), loxonemataceans (0.5 percent), platycerataceans (0.4 percent), opisthobranchs (0.3 percent), and 

microdomataceans (0.1 percent).

Table 1 shows the distribution of genera (and subgenera) by number of specimens and percentage of the 

total of the more than 3,000 specimens collected for this 

study.

Three genera provide a continuum of species that are 

useful in dividing the Chainman Shale biostratigraphically. These genera are Retispira, represented by six 

species, Glabrocingulum, by nine species, and Lunulazona , by five species. The distribution of these species 

is discussed and shown in graphic form in the section 

on gastropod assemblages and their relationship to ammonoid and foraminiferal zones.

In the systematic section, the 79 species of gastropods 

collected in the Chainman Shale in the study area are
LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

TABLE 1. Taxonomic relationships and relative 

abundance of gastropods in the Chainman Shale

Family

Sinuitidae

Bellerophontidae

Sinuopeidae

Raphistomatidae

Eotomariidae

Lophospiridae

Phymatopleuridae

Murchisoniidae

Euomphalidae

Holopeidae

Platyceratidae

Elasmonematidae

Naticopsidae

Loxonematidae

Pseudozygopleuridae

Subulitidae

Meekospiridae

Family unknown

Genus (and subgenus)

Sinuitina (Sinuitina)

S. (Vorticina)

Euphemites

Bellerophon (Bellerophon)

Retispira

Rhineoderma

Trepospira (Angyomphalus)

T. (Trepospira)

Baylea

Mourlonia

Ptychomphalus

Deseretospira

Glabrocingulum (Glabrocingulum)

G. (Ananias)

Neilsonia

Lunulazona

Euconospira

Worthenia (Yochelsonospira)

Catazona

Dictyotomaria

Stegocoelia (Stegocoelia)

Bellazona

Straparollus (Euomphalus )

Cinclidonema

Platyceras (Platyceras)

Strophostylus

Anematina

Naticopsis (Naticopsis)

N. (Jedria)

Loxonema

Pseudozygopleura (Pseudozygopleura )

P. (Stephanozyga)

Bulimorpha

lanthinopsis

Soleniscus

Meekospira

Girtyspira

High-spired gastropods

Totals

No. of 

specimens

2

2

33

41

72

1

14

90

1

12

14

4

1,810

42

5

710

10

77

12

2

6

35

42

1

3

10

4

41

1

6

7

3

2

14

10

10

8

9

3,166

Percentage

0.06

.06

1.04

1.3

2.27

.03

.44

2.84

.03

.38

.44

.13

57.19

1.33

.16

22.43

.32

2.43

.38

.06

.19

1.11

1.33

.03

.09

.32

.13

1.3

.03

.19

.22

.09

.06

.44

.32

.32

.25

.28

100.02

described and figured. The number of specimens at 

each locality is recorded for all these species. One additional species, Ptychomphalina sp., known only by one 

specimen from the vicinity of Wendover, Nev., and described by Sadlick and Nielsen (1963) as part of the 

Chainman fauna, is redescribed, refigured, and reassessed herein.

DISTRIBUTION OF GASTROPODS IN 

THE STUDY AREA

The area under study includes the belt of Chainman 

Shale outcrops from Granite Mountain (T. 14 S., R. 16 

W.) south westward to the northern part of the Needle 

Range (north half of T. 25 S., R. 19 W.), an airline 

distance of approximately 70 miles (112 km). The study 

area is shown on the accompanying map (fig. 1). In the 

discussion that follows, we consider the various collecting localities and measured sections were measured 

through the Chainman Shale: Granite Mountain (eastern side); Skunk Spring in the Confusion Range; and 

Jensen Wash in the Burbank Hills. Fairly thick partial 

sections were measured northeast of Foote Ranch (eastern side of the Foote Range) and at Browns WashWallet Gulch in the Confusion Range. Many of the 

gastropod collections are from or related to these measured sections.

GRANITE MOUNTAIN SECTION

The northernmost section studied is at Granite 

Mountain, at the northern end of the Confusion Range, 

in Juab County, Utah. A section measured here by 

Gordon and C. A. Repenning in 1957 shows a thickness 

of 1,315 feet (401 m) for the Chainman Shale. The section is on the eastern slope of Granite Mountain, in the 

N V2 sec. 18 (unsurveyed), T. 14 S., R. 16 W., as indicated in figure 2.

The lowest gastropod in the Granite Mountain section is a crushed pleurotomariacean (USGS colln. 

28637-PC), identified as Rhineoderma sp., in float 

from a 3-ft (0.9-m) interval immediately below the base 

of the marker bed (Skunk Spring Limestone Member of 

Sadlick, 1966), 92 to 95 feet (28 to 29 m) above the base 

of the Chainman Shale.

A larger gastropod faunule in the Chainman Shale 

was found in a 5-foot (1.5-m) concretionary zone immediately overlying the 22-foot (6.7-m) marker bed, a 

massive grayish-black siliceous spiculitic limestone. 

The top of the marker bed is 111 feet (33.8 m) above the 

base of the formation. Occurring with ammonoids in 

the upper part of the Goniatites americanus Zone were 

the following gastropods (USGS colln. 17018-PC):

Sinuitina (Vorticina) vortex n. sp.

Euphemites sp. B

Retispira cf. R. textilis (Hall)

Trepospira (Angyomphalus) regularis n. sp.

Mourlonia venusta n. sp.

Glabrocingulum (Glabrocingulum) sp. A

Lunulazona nodomarginata (McChesney)

Bellazona bella (Walcott)

lanthinopsis? sp.

Another zone of grayish-black concretions is 15 to 18 

feet (4.6 to 5.5 m) above the top of the marker bed 

(USGS colln. 25558-PC) and contains ammonoids of 

the Goniatites americanus Zone. This unit also contains the following gastropods:

Trepospira (Angyomphalus) regularis n. sp.

Lunulazona nodomarginata (McChesney)

Glabrocingulum (Glabrocingulum) sp. A

Mourlonia venusta n. sp.

Loxonema sp.

A sample from the top 1 foot (0.3 m) of the marker 

bed yielded foraminifers that were assigned by B. L. 

Mamet (written commun., 1979) to his Foraminifer
40°00

39°00

114°00' 113°00'

FIGURE 1. Index map showing location of 15-minute quadrangles in western Utah that contain the Confusion Range and adjacent areas 

referred to in the text: 1, Granite Mountain; 2, Gandy; 3, Cowboy Pass; 4, Conger Range; 5, Conger Mountain; 6, Burbank Hills. Areas 

mentioned in the text are indicated on the appropriate quadrangle by letter: A, Granite Mountain measured section; B, area northeast of 

Foote Range; C, Foote Ranch partial section; D, Bishop Springs anticline; E, Indian Pass area; F, Skunk Spring measured section; G, southern 

part of Camp Canyon; H, Brown's Wash-Wallet Gulch partial section; I, Conger Spring area; J, area south of Conger Mountain; K, Coyote 

Pass area; L, Jensen Wash measured section; M, south slope of Burbank Hills; N, western part of Burbank Hills. The area referred to as 

"northern end of Needle Range" is in the Mormon Gap 71/2-minute quadrangle southwest of the Burbank Hills 15-minute quadrangle.
10 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

1 MILE

113°40'

0 1 KILOMETER

39°35'

FIGURE 2. Part of the Granite Mountain 15-minute quadrangle, enlarged to scale 1:31680 (2 inches = 1 mile), 

showing the position of Granite Mountain measured section.

Zone 16i. These two gastropod collections from the 

upper part of the Goniatites americanus Zone, therefore, are in that zone in which the position of the base 

of the Chesterian in the Illinois type section is uncertain (p. 0). The two gastropod species found elsewhere, 

Lunulazona nodomarginata (McChesney) and Bellazona bella (Walcott), both known from the Diamond 

Peak Formation in Nevada, and the first known also 

from the Moorefield Formation of Arkansas, come from 

beds of Meramecian age in those areas.

No gastropods have been found in the Goniatites 

multiliratus Zone, which immediately overlies the G. 

americanus Zone at Granite Mountain, where it is

about 10 feet (3.0 m) thick. Several gastropod species, 

however, occur in the overlying Goniatites granosus 

Zone. The lowest occurrence of this zone, on a little 

saddle about 600 feet (200 m) north of the line of section, is 40 feet (12.2 m) above the top of the marker bed. 

The bed, less than a foot (0.3 mm) thick, contains 

crushed fragments of goniatites and foraminifers identified by Mamet as characteristic of his Zone 16s. The 

Goniatites granosus fauna occurs generally in soft 

brown shale, containing tan to yellow phosphatic concretions; the fossils weather free from the shale. Wellpreserved gastropods were found 121 to 134 feet (36.9 

to 40.8 m) above the top of the marker bed associated
DISTRIBUTION OF GASTROPODS IN THE STUDY AREA 11

with the ammonoids (USGS collns. 17012-PC, 17015- 

PC, 17020-PC, 17037-PC, 25562-PC). These gastropods include the following species: 

Retispira cincta n. sp. 

Glabrocingulum (Glabrocingulum) granulosum n.

sp.

G, (G.) mephitifontis n. sp. 

Lunulazona costata Sadlick and Nielsen 

Bellazona polita n. sp.

The soft brown shale beds extend upward to 255 feet 

(77.7 m) above the top of the marker bed and are overlain by a dark-gary, very fine grained limestone that 

forms blocky ledges and is 39 feet (11.9 m) thick. B. L. 

Mamet (written commun., 1979) has reported his Zone 

17 Foraminifera at 6.6 and 21.3 feet (2.0 and 6.5 m) 

above the base of this unit. A fossil collection (USGS 

colln. 17087-PC) from the top few inches of this unit, in 

a limestone bed containing the trace fossil Zoophycus, 

contained Bellerophon (Bellerophon) vespertinus 

Gordon and Yochelson, and another specimen, probably from the same horizon, was found loose (USGS 

colln. 28627-PC). Collections made at intervals 

through the middle and upper parts of the Chainman 

Shale have yielded gastropods, as follows:

From 299 to 300 feet (91.1 to 91.4 m) above the 

marker bed, in beds of limestone in dusky yellowishbrown silty claystone (USGS colln. 17088-PC):

Straparollus (Euomphalus) intermedius Gordon

and Yochelson

Mamet (written commun., 1979) reported foraminifers 

of his Zone 17 at approximately this level.

From 457 to 459 feet (139.3 to 139.9 m) above the 

marker bed, in dusky brown argillaceous limestone 

(USGS colln. 17091-PC):

Lunulazona sadlicki n. sp.

From 464 to 474 feet (141.4 to 144.5 m) above the top 

of the marker bed, in limestone like that described immediately above, the following gastropods were collected (USGS colln. 17092-PC, 28628-PC):

Euphemites sp. indet.

Trepospira (Trepospira) sp.

Lunulazona sadlicki n. sp.

Cinclidonema sp.

The beds of this section for the next few hundred feet 

(100 m) are poorly fossiliferous. In a nearby section, 

measured by A. K. Armstrong and R. K. Hose, the 

impure limestones from roughly 525 to 930 feet (160 to 

283 m) above the top of the marker bed were found by 

Mamet to be highly spiculitic; the spiculites continue 

for some distance farther upsection. At 687 feet (209.4 

m) above the marker bed, a float limestone plate was 

recovered containing part of a goniatite, identified tentatively as Paracravenoceras barnettense (Plummer 

and Scott). This genus is typically found in Mamet

Foraminifer Zone 17 and suggests that this zone may 

range at least that high.

A collection made 849 to 854 feet (258.8 to 260.3 m) 

above the marker bed in medium-dark-gray siliceous 

limestone interbedded with claystone and some black 

chert contained the following gastropods (USGS colln. 

25249-PC):

Euphemites sacajawensis C. Branson 

Glabrocingulum (Glabrocingulum) quadrigatum

Sadlick and Nielsen

This and the rest of the collections from the Chainman 

Shale higher in the Granite Mountain measured section are those normally found in the Cravenoceras hesperium Ammonoid Zone, which correlates with the 

lower part of Mamet's Foraminifer Zone 18.

At 942 to 943 feet (287.1 to 287.4 m) above the top of 

the marker bed, the following were collected (USGS 

colln. 17095-PC):

Retispira nolani Gordon and Yochelson 

Glabrocingulum (Glabrocingulum) quadrigatum

Sadlick and Nielsen

Worthenia (Yochelsonospira) tenuilineata Girty 

In a 22-foot (6.7-m) unit containing large caninoid 

corals, 1,018 to 1,040 feet (310.3 to 317.0 m) above the 

marker bed, the following gastropods were found 

(USGS collns. 17104-PC, 20547-PC, 25257-PC): 

Catazona rudilirata Gordon and Yochelson 

Straparollus (Euomphalus) nodibasis n. sp. 

Naticopsis (Naticopsis) confusionensis n. sp. 

At 1,050 to 1,054 feet (320.0 to 321.3 m) above the 

marker bed, a brownish to medium-gray limestone containing silicified fossils yielded (USGS colln. 17098- 

PC):

Straparollus (Euomphalus) nodibasis n. sp. 

At 1,061 to 1,065 feet (323.4 to 324.6 m) above the top 

of the marker bed, a gray, partly siliceous, fine-grained 

limestone, weathering tan to orange, contained (USGS 

colln. 17099-PC):

Straparollus (Euomphalus) intermedius Gordon

and Yochelson

A 3-foot (1-m) bed of medium-dark-gray, fine-grained 

limestone containing silicified fossils, 1,075 to 1,078 

feet (327.7 to 328.6 m) above the top of the marker bed, 

has provided the following gastropods (USGS colln. 

25252-PC):

Glabrocingulum (Glabrocingulum) quadrigatum

Sadlick and Nielsen 

Neilsonia sp. 

Straparollus (Euomphalus) intermedius Gordon

and Yochelson 

Stegocoelia (Stegocoelia?) sp. 

Strophostylus cf. S. nevadensis Gordon and

Yochelson 

Naticopsis (Naticopsis?) clinovata n. sp.
12 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Pseudozygopleura (Pseudozygopleura)! sp.

Meekospira sp.

Finally, a soft medium-dark-gray organic detrital 

limestone, 1,108 to 1108.5 feet (337.7 to 337.9 m) above 

the top of the marker bed contains (USGS colln. 17101- 

PC):

Platyceras (Platyceras) cf. P. (P.) subrotundum 

Snider

AREA NORTHEAST OF FOOTE RANGE

At the northern end of the valley between the Foote 

Range and Chevron Ridge are several Chainman outcrops on the valley floor, east of a narrow northwesttrending ridge that exposes beds of the upper part of 

the Chainman Shale and the lower part of the Ely 

Limestone. A collection from a small isolated patch of 

Chainman Shale in the NE V4 SW V4 SW 1/4 SE 1/4 sec. 

24 contains the following two gastropod species from 

the upper part of the Paracravenoceras barnettense ammonoid Zone (USGS colln. 28623-PC):

Glabrocingulum (Glabrocingulwn) confusionense 

n. sp.

G. (Glabrocingulum?) hosei n. sp. 

G. (G.) confusionense was also reported by Sadlick and 

Nielsen (1963, p. 1098-1100, pi. 150, figs. 5-8) as 

Glabrocingulum quadrigatum n. sp. from an oilcompany locality somewhere in sec. 24, T. 15 S., R. 18 

W.; a more precise locality was not disclosed. We have 

examined the three specimens in this lot, included 

among the paratypes of G. quadrigatum and regard 

them as conspecific with G. (G.) confusionense n. sp.

Several collections were made in the E V2 sec. 25, 

T. 15 S., R. 18 W. The contact between beds of the 

Paracravenoceras barnettense and Cravenoceras hesperium Ammonoid Zones is exposed in this area. Fossils from the lower zone were collected in the SE V4 

SE V4 SE 1/4 NE V4 sec. 25 (USGS colln. 25557-PC). 

These included the same two gastropod species:

Glabrocingulum (Glabrocingulum) confusionense 

n. sp.

G. (G?) hosei n. sp.

A short distance northwest of this locality, in the 

SW V4 SE 1/4 NE V4 sec. 25, Hose made collections from 

each of the two zones. The one containing Paracravenoceras barnettense (USGS colln. 19602-PC) yielded 

Glabrocingulum (Glabrocingulum?) hosei n. sp., and 

the other, from the basal 10 feet (3 m) of the Cravenoceras hesperium Zone (USGS colln. 19604-PC) contained two species:

Glabrocingulum (Glabrocingulum) quadrigatum

Sadlick and Nielsen 

Lunulazona utahensis n. sp.

FOOTE RANCH PARTIAL SECTION

Four miles (6.4 km) northeast of Foote Ranch is a 

much-visited fossil-collecting site, known as the Foote 

Ranch locality. In the early 1950's, weathered-out fossils, mostly brachiopods, were strewn about by the 

thousands, but visits by scores of collectors have taken 

their toll, and today one has to search to find a single 

loose fossil. The last mile of the access road from the 

Foote Ranch to this locality follows a northeasttrending wash cut through the Foote Range, about 

2 miles (3.2 km) south of its northern tip. The collecting 

locality was about 50 to 100 yards (45 to 90 m) north of 

the wash, at the foot of the eastern slope of the range.

This area is in the Gandy NE 7 1/2-minute quadrangle, the geology of which was mapped by Hose and 

Ziony (1963). A partial section of the upper part of the 

Chainman Shale, measured by Hose and Gordon in 

1957, together with a section measured by Gordon and 

T. W. Henry in 1983, provides documentation of the 

upper 469 feet (143.0 m) of this formation, in the SE V4 

sec. 36, T. 15 S., R. 17 W. (see fig. 3). The lower part of 

the Hose-Gordon section began at a 1-foot-thick (0.3- 

m) bed of light-brown sandstone near the NW cor. sec. 

31, T. 15 V2 S., R. 17 W., and continued southwestward 

on the north side of the main wash. The 15 feet (4.6 m) 

of shale immediately overlying the sandstone bed contains abundant basal and other plates of Agassizocrinus. A bed of grayish-black, micritic, somewhat nodular limestone, containing Leiorhynchoidea carbonifera 

(Girty) and Richardsonites merriami (Youngquist) is 

65 feet (19.8 m) above the sandstone bed.

A substantial part of the overlying section along the 

wash is missing because of faulting. To avoid this area, 

the Gordon-Henry section was measured up the eastern slope of the Foote Range, beginning about 500 feet 

(152 m) north of the wash and ending at the summit of 

the first ridge, capped by the basal bed of the Ely Limestone. The thickness of the Chainman Shale in this 

section, from the top of the Agassizocrinus -bearing 

shale to the base of the Ely, is 452.7 feet (138.0 m). An 

easily recognized limestone bed, 0.3 foot (0.1 m) thick, 

packed with narrow spiriferids, is 265.2 to 265.5 feet 

(80.8 to 80.9 m) below the top of the Chainman. Highly 

fossiliferous shale and some limestone is 14.5 to 51.5 

feet (4.4 to 15.7 m) below the top of the formation; this 

interval provided the fossils at the nearby Foote Ranch 

locality. The top 14.5-foot (4.4-m)-thick unit of the 

Chainman is a moderately fossiliferous argillaceous 

platy limestone.

The key fossil-bearing beds in the measured sections 

are essential for determining the stratigraphic position 

of gastropods collected in the highly faulted Chainman 

Shale area in sec. 31, T. 15 1/2 S., R. 17 W., and the N 1/4 

sec. 6, T. 16 S., R. 17 W., where the gastropods are fairly
DISTRIBUTION OF GASTROPODS IN THE STUDY AREA 13

113°50'

39"30'

1 MILE

0 1 KILOMETER

FIGURE 3. Part of the Gandy 15-minute quadrangle, enlarged to 

scale 1:31680 (2 inches = 1 mile), showing the position of the Foote 

Ranch measured section.

common. The Ely Limestone in this area is downfaulted and locally thrust over the Chainman, and it 

cuts out some of the beds in the upper part of the Chainman (see map by Hose and Ziony, 1963).

The stratigraphically lowest collection, that farthest 

to the southeast, is from soft grayish-black shale in the

NE l/4 NE lk sec. 6 (unsurveyed), about 1.5 miles (2.4 

km) southeast of the Foote Ranch locality. This collection is estimated to be somewhere between 470 and 520 

feet (143.3-158.5 m) below the top of the Chainman. 

Weathering from shale, along with Cravenoceras hesperium Miller and Furnish, are the following gastropods (USGS colln. 17032-PC):

Bellerophon (Bellerophon) sp. indet.

Trepospira (Trepospira) diadema n. sp.

Glabrocingulum (Glabrocingulum) quadrigatum 

Sadlick and Nielsen

Worthenia (Yochelsonospira) tenuilineata Girty

Straparollus (Euomphalus) intermedius Gordon

and Yochelson

Fossils of the Agassizocrinus -bearing shale were recognized in the SE i/4 SE i/4 sec. 31, T. 15 1/2 S., R. 17 W., 

weathering from the northern slope of a small ridge. 

Two specimens of Worthenia (Yochelsonospira) 

tenuilineata Girty were found at this locality, in USGS 

colln. 25259-PC.

Another collection, about 0.25 mile (0.4 km) southeast of the previous one, is from a limestone pod, 

roughly 4 feet (1.2 m) long and 0.5 foot (0.15 m) thick. 

The collection is near the saddle on the southwestern 

side of a prominent hill capped by a thrust-in block of 

Ely Limestone. It contains numerous valves oflnflatia, 

and because fragments oflnflatia shells are common in 

the measured section between the Agassizocrinus - 

bearing shale and the Leiorhynchoidea-Richardsonites 

limestone bed, the collection believed to belong stratigraphically in that part of the section. This collection, 

from the NE 1/4 NE V4 sec. 6 (unsurveyed), T. 16 S., R. 

17 W., contains the following gastropods (USGS colln. 

25274-PC):

Bellerophon (Bellerophon) welshi n. sp.

Glabrocingulum (Glabrocingulum) quadrigatum 

Sadlick and Nielsen

Neilsonia sp. indet.

Worthenia (Yochelsonospira) tenuilineata Girty

Soleniscus sp. B

Meekospira sp.

The Leiorhynchoidea-Richardsonites bed has also 

yielded gastropods at an outcrop in a fault block in the 

SE V4 fractional sec. 31, T. 15 V2 S., R. 17 W., where the 

bed is about 2 feet (0.6 m) thick. Species from two collections (USGS collns. 15370-PC, 17024-PC) include:

Glabrocingulum (Glabrocingulum) sp. C

Lunulazona? cf. L. sablei (Yochelson and Dutro)

Worthenia (Yochelsonospira) tenuilineata Girty

lanthinopsis sp. A

Another fossil collection, including Euloxoceras, was 

made from a foot of shale about 25 feet (7.6 m) above 

the Leiorhynchoidea-Richardsonites bed. The gastropods include (USGS colln. 22883-PC):
14 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Euphemites sp. A

Bellerophon (Bellerophon?) sp. A

Trepospira (Trepospira) diadema n. sp.

Glabrocingulum (Glabrocingulum) binodosum 

Sadlick and Nielsen

lanthinopsis gandyensis n. sp. 

The same horizon probably is represented by a collection (USGS colln. 25275-PC) in the NW V4 NW V4 

sec. 6 (unsurveyed), T. 16 S., R. 17 W., in which Euloxoceras is associated with Bellerophon (Bellerophon?) 

sp. A.

The bed containing the narrow spiriferids is recognizable at several points within the faulted area. At 

one of them, in the NE V4 NE V4 fractional sec. 31, 

T. 15 1/2 S., R. 17 W., the 25 feet (7.6 m) of shale overlying the spiriferid bed contains the following gastropods, which weather out (USGS colln. 25551-PC):

Euphemites sp. A

Bellerophon (Bellerophon) vespertinus Gordon and 

Yochelson

Retispira nolani Gordon and Yochelson?

Trepospira (Trepospira) diadema n. sp.

Glabrocingulum (Glabrocingulum) quadrigatum 

Sadlick and Nielsen

Worthenia (Yochelsonospira) tenuilineata Girty

Straparollus (Euomphalus) intermedius Gordon 

and Yochelson

lanthinopsis sp. B

At another locality, about 500 feet (152.4 m) westnorthwest of the previous one and at a slightly higher 

level, but perhaps within the stratigraphic limits of the 

last collection, two gastropods species are present 

(USGS colln. 25553-PC):

Worthenia (Yochelsonospira) tenuilineata Girty

Naticopsis (Naticopsis) confusionensis n. sp. 

A collection (USGS colln. 15372-PC) made by R. K. 

Hose from the uppermost beds of the Chainman Shale 

at the original Foote Ranch locality contains a single 

specimen of Glabrocingulum (Glabrocingulum) 

binodosum. Another collection (USGS colln. 22876- 

PC) from limestone in the uppermost 30 feet (9.1 m) of 

the formation contains several specimens of Naticopsis 

(Naticopsis) confusionensis n. sp.

BISHOP SPRINGS ANTICLINE

The elongate domelike structure known as the 

Bishop Springs anticline occupies a rather flat valley 

between the Foote Range at the west and Chevron 

Ridge to the east, both of which are formed by extensive 

exposures of Ely Limestone. The center of the dome 

contains an area, about half a mile (0.8 km) across, of 

Upper Devonian and Lower Mississippian Pilot Shale. 

This area is surrounded by a ring of outcrops of the 

Lower Mississippian Joana Limestone, elongate to the

south, where it extends in a low ridge to about 2 miles 

(3.2 km) south of the Pilot Shale outcrop. Along the 

western limb of the anticline, the outcrop belt of the 

Chainman Shale has been narrowed greatly by faulting. The proximity of Lower Mississippian and Lower 

Pennsylvanian limestone beds here led Zeller (1957, p. 

687, 688) to suggest that this was a positive area during the Late Mississippian into the Early Pennsylvanian; as a result, no Upper Mississippian sediments 

were deposited here. The Chainman Shale is present, 

however, in fault slices flanking the Bishop Springs 

anticline. Ironically, this is the one area in the entire 

Chainman outcrop belt where all the Late Mississippian ammonoid zones are present. All the gastropods 

found in this area are associated with ammonoids.

The earliest gastropods here are those of the Goniatites granosus Zone; they occur in association 

with G. granosus in an outcrop in the 

SW V4 SE V4 SE V4 sec. 7 (unsurveyed), T. 16 S., R. 17 W., 

about 3/8 mile (0.6 km) south-southwest of the abandoned oil well shown on the Gandy N.E. 7 1/2-minute 

quadrangle geologic map (Hose and Ziony, 1963). The 

gastropods include (USGS colln. 20446-PC):

Retispira cincta n. sp.

Glabrocingulum (Glabrocingulum) granulosum n. 

sp.

Lunulazona costata Sadlick and Nielsen

Straparollid steinkern

About 1.25 miles (2 km) to the north-northeast is a 

similar shoft-shale zone containing fossils of the Goniatites granosus Zone, but lacking gastropods. Thirty 

feet (9.1 m) higher in the section at that locality is a bed 

of medium-dark-gray limestone containing Cravenoceras kingi (Hall and Whitfield), marking the base of 

the Paracravenoceras barnettense Zone (USGS colln. 

20455-PC). A single specimen of Bellazonapolita n. sp. 

was found loose but associated with the limestone bed.

Most of the fossiliferous Chainman outcrops in the 

southern part of the Bishop Springs anticline are 

assignable to the upper part of the Paracravenoceras 

barnettense Zone and the lower part of the Cravenoceras hesperium Zone. One narrow north-heading elongate outcrop of soft olive-colored shale occurs near the 

western edge of the SE V4 SW V4 sec. 20 (unsurveyed), 

T. 16 N., R. 17 W. This outcrop is 2 3/8 miles (3.8 km) 

south-southeast of the abandoned Bishop Springs oil 

drill hole. The faunal assemblage at this locality includes the aulacocerid Hematites barbarae Flower and 

Gordon and the ammonoid Paracravenoceras barnettense (Plummer and Scott). The following gastropods are present (USGS colln. 20448-PC):

Glabrocingulum (Glabrocingulum) confusionense

n. sp. 

G. (G.?) hosein. sp.
DISTRIBUTION OF GASTROPODS IN THE STUDY AREA 15

The same cephalopods and G. (G.) confusionense n. sp. 

occur a quarter of a mile (0.4 km) to the east (USGS 

colln. 19603-PC).

Six collections were made in an outcrop 

of slightly younger rocks in the 

SE 1/4 NW 1/4 NW 1/4 sec. 20 (unsurveyed), T. 16 N, R 17 W. 

The section in this fault block consists of nearly 30 feel; 

(9.1 m) of dark-gray limestone alternating with 

brownish-gray shale, the limestone beds 6 inches to 

1 foot (0.15 to 0.3 m) thick. The common ammonoid in 

the limestone beds is Cravenoceras hesperium Miller 

and Furnish. The gastropods are distributed as follows: 

In the lowermost limestone bed, 1 foot (0.3 m) thick 

(USGS colln. 25260-PC):

Lunulazona utahensis n. sp. 

Anematina sp. 

Loxonema n. sp.

Five feet (1.5 m) higher, in 1 foot (0.3 m) of brownishgray shale (USGS colln. 20443-PC):

Glabrocingulum (Glabrocingulum) quadrigatum

Sadlick and Nielsen 

Lunulazona utahensis n. sp.

In a 1-foot (0.3-m) limestone bed, 5 feet (1.5 m) higher 

still (USGS colln. 20444-PC):

Lunulazona utahensis n sp.

In a 6-inch (0.15-m) limestone bed, 27 feet (8.2 m) 

above the top of the lowermost limestone bed and 15 

feet (4.6 m) above the top of 20444-PC (USGS colln. 

20445-PC):

Lunulazona utahensis n. sp.

An earlier collection (USGS colln. 17022-PC) made 

from the lower half of this sequence contains both 

G. (Glabrocingulum) quadrigatum and L. utahensis 

n. sp.

INDIAN PASS AREA

The Chainman Shale is exposed at the western edge 

of Chevron Ridge in the vicinity of Indian Pass. A collection made by R. K. Hose from a coarse-grained 

grayish-black limestone bed between two quartzite 

beds in a fault block about 1 mile (1.6 km) north of 

Indian Pass (USGS colln. 16959-PC) included Lunulazona? aff. L.? sablei Yochelson and Dutro. As the bed 

also contains Leiorhynchoidea carbonifera (Girty) and 

only the uppermost beds of the Chainman are exposed 

in this area, this may be the same grayish-black limestone bed that carries Richardsonites merriami 

(Youngquist) in the Foote Ranch section. The bed containing narrow Anthracospirifer in the Foote Ranch 

measured section is also exposed in a fault block in this 

area. A collection made 1,500 feet (457 m) north of the 

west end of Indian Pass, 4 to 8 feet (1.2 to 2.4 m) below 

the top of the Chainman, contains the following gastropods (USGS colln. 17003-PC):

Retispira jensenensis n. sp.?

Straparollus (Euomphalus) interrnedius Gordon

and Yochelson 

Naticopsis (Naticopsis) confusionensis n. sp.

SKUNK SPRING SECTION

Several of our collections are from the vicinity of 

Skunk Spring, in the N 1/2 SE 1/4 sec. 28 (unsurveyed), 

T. 17 S., R. 16 W. A section was measured there by 

R. K. Hose in 1954, and he made many of the fossil 

collections in this area. The upper part of this section 

was measured along the northern slope of Willow 

Spring Canyon, shown on the geologic map of the Cowboy Pass S.W. quadrangle of Hose and Repenning 

(1964), about a quarter of a mile (0.4 km) north of 

Skunk Spring (fig. 4).

The lower 230 feet (70.1 m) of predominantly silty 

shale in the Skunk Spring section is barren of megafossils. The lower marker bed is at the top of a 20-foot 

(6.1-m) unit of limestone, the top of which is 247 feet 

(75.3 m) above the base of the Chainman Shale. The 

stratigraphically lowest gastropods in this section 

weather from soft clay shale and occur with goniatites 

of the Goniatites granosus Zone, 394 to 407 feet (120.1 

to 124.1 m) above the base of the formation (USGS 

colln. 15354-PC), where a rare pleurotomariacean species was found:

Glabrocingulum (Glabrocingulum) mephitifontis 

n. sp.

The same interval, three-eighths of a mile (0.6 km) 

south of Skunk Spring has yielded another equally rare 

bellerophontacean species (USGS colln. 25261-PC): 

Sinuitina (Sinuitina) crispa n. sp.

Fossils from the same zone were found also at a 

higher level in silty limestone three-eighths of a mile 

(0.6 km) north of Skunk Spring and 24 feet (7.3 m) west 

of the Camp Canyon road in a bed roughly 700 feet 

(213.4 m) above the base of the formation. Occurring 

with crushed shells of Goniatites granosus Portlock and 

G. choctawensis Shumard are poorly preserved specimens of Bellazona polita n. sp. (USGS colln. 14557- 

PC).

Most of the gastropods in the Skunk Spring section 

came from a massive limestone member at Willow Gap. 

Here, where the Willow Spring Canyon cuts through it, 

the member is 318 feet (96.9 m) thick. Sadlick (1966) 

called this limestone the Willow Gap Limestone Member. However, because this name was published only in 

abstract, it has not been accepted by the USGS. We 

regard this lenticular limestone mass as a large shoal 

in a shallow area of the Chainman sea. This limestone 

deposit is presently recognizable for a little more than 

10 miles (16 km), from the large alluvial fan emanating
16

113°40'

39°20'

LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

base of this unit is 1,262 feet (384.6 m) above the base 

of the Chainman Shale. The fossil collections listed below are all from Willow Spring Canyon (Willow Gap). 

Intervals given are measured in vertical section from 

the base of the lowest massive limestone of the member.

In the lowermost 14 feet (4.3 m) of fine-grained darkgray massive limestone, the following gastropods were 

collected (USGS colln. 15355-PC):

Bellerophon (Bellerophon) sp. indet. 

Straparollus (Euomphalus) nodibasis n. sp. 

S. (E.) intermedius Gordon and Yochelson? 

Naticopsis (Naticopsis) cf. N. (N.) genevievensis

Meek and Worthen 

N. (N.?) clinovata n. sp.

Pseudozygopleura (Stephanozyga) claviger n. sp. 

In another dark-gray fine-grained limestone unit, 44 

to 76 feet (13.4 to 23.2 m) above the base of the member, 

a single gastropod occurs with the brachiopod faunule 

(USGS colln. 15356-PC):

Soleniscus sp. B

From medium-dark-gray dense limestone, 110 feet 

(33.5 m) above the base of the limestone member, a 

fossil collection (USGS colln. 25271-PC) includes the 

following gastropods:

Bellerophon (Bellerophon) ? sp. indet. 

Pleurotomariacean, gen. and sp. indet. 

Strophostylus cf. S. nevadensis Gordon and

Yochelson 

Naticopsis (Naticopsis) cf. N. (N.) genevievensis

Meek and Worthen? 

Soleniscus? sp. 

Girtyspira circumsecta n. sp. 

Meekospira sp.

From similar fine-grained to dense limestone, 200 

feet (61.0 m) above the base of the limestone member 

(USGS colln. 15358-PC):

Bellerophon (Bellerophon) vespertinus Gordon and

Yochelson?

Straparollus (Euomphalus) nodibasis n. sp. 

Catazona rudilirata Gordon and Yochelson 

From 221 feet (67.4 m) above the base (USGS colln. 

15359-PC):

Bellerophontacean, gen. and sp. indet. 

Naticopsis (Naticopsis) confusionensis n. sp. 

From 237 to 238 feet (72.2 to 72.5 m) above the base 

of the limestone member (USGS collns. 15361-PC, 

25272-PC):

Bellerophon (Bellerophon) needlensis n. sp.?

B. (B.) sp. indet.

Naticopsis (Naticopsis) cf. N. (N.) genevievensis

Meek and Worthen

From medium-dark-gray and pale-yellowish-brown 

dense to granular limestone 289 feet (88.1 m) above the

1 MILE

u 1 KILOMETER

FIGURE 4. Part of the Cowboy Pass 15-minute quadrangle, enlarged 

to scale 1:31680 (2 inches = 1 mile), showing the position of the 

Skunk Spring measured section.

from Cowboy Pass southwest to Brown's Wash south of 

Conger Mountain.

Fossils in this limestone are predominantly brachiopods, but a few gastropods are present in most collections. Samples collected by Gordon for foraminiferal 

study in 1969 were examined by Bernard Mamet (written commun., 1970), who reported that all of the limestone member belongs in his Foraminifer Zone 18. The
DISTRIBUTION OF GASTROPODS IN THE STUDY AREA 17

base of the limestone member (USGS collns. 15362- 

PC, 15375-PC):

Bellerophon (Bellerophon) sp. indet.

Catazona rudilirata Gordon and Yochelson

Straparollus (Euomphalus) nodibasis n. sp.

Naticopsis (Naticopsis) confusionensis n. sp.

N. (N.?) clinovata n. sp.

Pseudozygpleura (Stephanozyga) claviger n. sp.? 

From the same unit, 300 feet (91.4 m) above the base 

of the limestone member (USGS collns. 15363-PC, 

25563-PC):

Bellerophon (Bellerophon) sp. indet.

Straparollus (Euomphalus) nodibasis n. sp.

Strophostylus cf. S. nevadensis Gordon and 

Yochelson

Naticopsis (Naticopsis) confusionensis n. sp.

N. (N.) cf. N. (N.) genevievensis Meek and Worthen

Naticopsis (Jedria) sp.

Most of the bellerophontaceans in this limestone unit 

have been so damaged either by silicification or recrystallization, or both, that they have been generally rendered unidentifiable. The other species have been 

much less affected. Some of the naticopsids have undergone diagenesis, but most have well-preserved surfaces, the damage to the shells being mainly distortion 

due to partial crushing.

The uppermost 14.5 feet (4.4 m) of interbedded dense 

to sublithographic limestone and coarsely granular 

limestone contains large caninoid corals. This unit is 

overlain by a 5.5-foot (1.7-m) covered zone, probably of 

thin-bedded limestone, followed by a 2.4-foot (0.7-m) 

clastic limestone bed. This highest limestone is conglomeratic, the clasts ranging from granule to pebble 

size, the pebbles as much as 2.5 cm long. Limestone 

pebbles are subrounded to subangular; sparse small 

rounded chert pebbles are also present.

The uppermost unit in the Chainman, 253 feet 

(77.1 m) thick, is composed of grayish-black shale, 

mostly covered. At Willow Gap, it is in fault contact 

with the underlying limestone unit, as shown on the 

Cowboy Pass S.W. geologic map (Hose and Repenning, 

1963). From 108 to 138 feet (32.9 to 42.1 m) above the 

base of the unit, the shale is interbedded with darkgray silty limestone weathering tan and locally earthy 

and yellowish. Brachiopods of the Rhipidomella 

nevadensis Zone weather out from this limy interval. 

Two collections, one about in the line of section and the 

other approximately 1,000 feet (305 m) to the north, 

include the following gastropods (USGS collns. 14558- 

PC, 14559-PC):

Bellerophon (Bellerophon) sp. indet.

Glabrocingulum (Glabrocingulum) binodosum 

Sadlick and Nielsen

Naticopsis (Naticopsis) confusionensis n. sp.

The total thickness of the Chainman Shale in this 

section is 1,840 feet (560.8 m).

SOUTHERN PART OF CAMP CANYON

Another locality where gastropods were found in the 

Goniatites granosus Zone is 4.05 miles (6.5 km) south 

by road from the water tank at Skunk Spring in the 

northern part of the Conger Mountain quadrangle. 

This locality is just east of the Camp Canyon road and 

1.9 miles (3.04 km) north-northeast of the place at 

which this road crosses the wash of Little Mile-and-aHalf Canyon, in the NE V4 SW V4 SE i/4 sec. 17, T. 18 

S., R. 16 S. The weathered-out fossils include two gastropods (USGS colln. 14553-PC):

Lunulazona costata Sadlick and Nielsen

Bellazona polita n. sp.

BROWN'S WASH-WALLET GULCH PARTIAL SECTION

About 1.4 miles (2.24 km) west of the summit of Conger Mountain is a large ravine, known as Wallet Gulch, 

cut into the upper beds of the Chainman Shale. It 

drains south from the western part of Conger Mountain, then turns abruptly west into a narrow defile cut 

through the Ely Limestone. The eastern side of this 

gulch is formed by a ridge of limestone that separates 

Wallet Gulch from Brown's Wash. A partial section 

was measured along the line indicated in figure 5. The 

limestone unit is 343 feet (104.6 m) thick and occupies 

the same part of the Chainman section that the similar 

limestone unit occupies in the Skunk Spring-Willow 

Gap section. Presumably, the limestone beds in these 

two areas are part of the same carbonate deposit. Two 

collections were made in the limestone unit. The lower 

one is from the basal 1 foot (30 cm) at midslope on the 

west side of Brown's Wash, due east of the ridge that 

flanks Wallet Gulch on the south. The fossils are 

coarsely silicified, which precludes identification of 

some of them.

This basal bed contains the following gastropods 

(USGS colln. 25566-PC):

Euphemites nevadensis Gordon and Yochelson?

Bellerophon (Bellerophon) sp. indet.

Retispira sp. indet.

Baylea? sp.

Catazona rudilirata Gordon and Yochelson

Dictyotomaria sp.

Straparollus (Euomphalus) intermedius Gordon

and Yochelson

Naticopsis (Naticopsis) confusionensis n. sp. 

N. (N. ?) clinovata n. sp. 

Bulimorpha sp. 

Meekospira? sp. 

High-spired tiny gastropods, gen. and sp. indet.
18 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

113°4S' 

39°15'

1 MILE

0 1 KILOMETER

FIGURE 5. Part of the Conger Mountain 15-minute quadrangle, enlarged to scale 1:31680 (2 inches = 1 mile), showing the position of 

the Brown's Wash-Wallet Gulch measured section.

The second collection was made from a limestone 15 

feet (4.6 m) thick that caps the ridge between Brown's 

Wash and Wallet Gulch. Its base is 147 feet (44.8 m) 

above the base, and the top of it is 181 feet (55.2 m) 

below the top of the carbonate unit. Preservation of the

fossils is similar to that below. The collection includes 

the following gastropods (USGS colln. 17214-PC):

Euphemites? sp. indet.

Retispira sp. indet.

Catazona rudilirata Gordon and Yochelson

Palaeostylus sp.

High-spired tiny gastropods, gen. and sp. indet. 

The limestone unit is capped by 1.5 feet (0.5 m) of 

quartzitic sandstone, overlying which is 353 feet 

(107.6 m) of shale containing scattered beds of limestone and limestone, up to the base of the Ely Limestone. In the interval 11.5 to 41.3 feet (3.5 to 12.6 m) 

above the base of the shale sequence are weathered-out 

fossils, mostly brachiopods and two gastropod species 

(USGS colln. 15364-PC):

Worthenia (Yochelsonospira) tenuilineata Girty

Pseudozygopleura (Pseudozygopleura) ? lauta n. sp. 

From a siltstone, 4.5 feet (1.4 m) thick, the base of 

which is 134 feet (40.8 m) above the quartzitic sandstone bed, and in the overlying 33 feet (10.1 m) of clay 

shale, another brachiopod faunule contains the following gastropods (USGS collns. 15365-PC, 16997-PC, 

25269-PC):

Bellerophon (Bellerophon) vespertinus Gordon and 

Yochelson?

^Worthenia (Yochelsonospira) tenuilineata Girty

Straparollus (Euomphalus) intermedius Gordon 

and Yochelson

Strophostylus cf. S. nevadensis Gordon and 

Yochelson

CONGER SPRING AREA

The upper beds of the Chainman Shale are exposed 

in the vicinity of Conger Spring in the NE V4 NW lk 

sec. 2, T. 19 S., R. 17 W. Brachiopods of these beds are 

those of the Rhipidomella nevadensis Zone, the uppermost brachiopod zone in the Chainman, particularly 

that part of the zone in which the productoid Carlinia 

phillipsi (Norwood and Pratten) also occurs. A small 

area of hillslope about 1,000 feet (305 m) south by east 

from the spring has provided a large collection of brachiopods (USGS colln. 17021-PC). A partial section 

measured by Gordon in June 1959, shows that a fauna 

is weathering from 14 feet (4.3 m) of greenish-gray 

shale, the top of which is 22 feet (6.7 m) below the base 

of the Ely Limestone. With these brachiopods are associated a few gastropods:

Trepospira (Trepospira) diadema n. sp.

Euconospira desereti n. sp.

Worthenia (Yochelsonospira) tenuilineata Girty

Straparollus (Euomphalus) intermedius Gordon 

and Yochelson

Naticopsis (Naticopsis) confusionensis n. sp.

Soleniscus sp. B
DISTRIBUTION OF GASTROPODS IN THE STUDY AREA 19

AREA SOUTH OF CONGER MOUNTAIN

The southernmost point where one or more gastropods were found in the Goniatites granosus Zone is 

2.4 miles (3.8 km) southwest of the southern end of 

Conger Mountain and 0.1 mile (0.16 km) east of the 

road in a 30-foot (9.1-m) interval of shale that begins 90 

feet (27.4 m) stratigraphically above the top of the 

marker bed. The collection (USGS colln. 17250-PC) 

includes a specimen of Retispira cincta n. sp.

COYOTE PASS AREA

On the east slope of the Conger Range, a southsouthwest-trending extension of the Confusion Range, 

in a small reentrant just east of Coyote Pass, are several exposures of Chainman Shale. About a quarter of 

a mile (0.4 km) east-southeast of Coyote Pass, is a low 

knoll where a dark-brownish-gray limestone bed crops 

out, which contains corals, brachiopods, and mollusks. 

The mollusks include the cephalopods Rayonnoceras 

sp. andRichardsonites merriami (Youngquist). The bed 

seems to occupy a slightly higher stratigraphic position 

than does the R. merriami bed in the northern part of 

the Foote Range, judging from the associated fossils. 

The following gastropods were found in this bed (USGS 

colln. 22880-PC):

Euphemites sp. A

E. cracens n. sp.

Bellerophon (Bellerophon) vespertinus Gordon and 

Yochelson?

Retispira sp.

Glabrocingulum (Ananias) seminudum Gordon 

and Yochelson

G. (Glabrocingulum?) sp. B

Euconospira gradilis n. sp.

Straparollus (Euomphalus) intermedius Gordon 

and Yochelson?

Soleniscus sp. B

The bed also contains the brachiopod Rhipidomella 

nevadensis (Meek), and, so far as could be determined, 

this bed occurs stratigraphically about 20 feet (6.1 m) 

above the first appearance of that species.

JENSEN WASH SECTION

The Chainman Shale is well exposed on the northern 

slope of the Burbank Hills in the E 1/2 sec. 35, T. 22 S., 

R. 18 W. A section was measured there in 1957 by 

Gordon, beginning in the SE V4 SE V4 sec. 35, continuing northwest into the NW lk SE lk sec. 35, and shifting northeastward along the upper of two beds that 

contain Cravenoceras hesperium Miller and Furnish 

and other ammonoids of that zone, the upper part of the 

section being measured in the NE V4 NE lk sec. 35 

(fig. 6). The total thickness of the Chainman Shale at

38°50'

1 KILOMETER

FIGURE 6. Part of the Burbank Hills 15-minute quadrangle, enlarged to scale 1:31680 (2 inches = 1 mile), showing the position of 

the Jensen Wash measured section.

Jensen Wash is 2,203 feet (671.5 m). Five lithologic 

units containing gastropods were found in the line of 

section.

In this area, no gastropods were found in the lower 

third of the formation. Three ammonoid zones based 

upon species of the genus Goniatites are present. The 

earliest gastropods in the Chainman of this area appear in beds of middle Chesterian age. A 1.5-foot 

(0.5-m) calcareous shale bed, in the dark-gray silty 

shale sequence that occupies the lower part of the 

Paracravenoceras barnettense Ammonoid Zone, is 703 

feet (214.3 m) above the base of the Chainman and 44 

feet (13.4 m) above the lowest bed containing
20 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Paracravenoceras. Common in this bed are two gastropod species (USGS collns. 17201-PC, 25546-PC):

Ptychomphalina burbankensis n. sp.

Lunulazona sadlicki n. sp.

Higher in the same ammonoid zone, a 20-foot (6.1-m) 

unit of soft dark-brownish-gray calcareous shale, 980 

to 1,000 feet (298.7 to 304.8 m) above the base of the 

Chainman, contains innumerable pebble-sized darkbrown siliceous siltstone nodules and abundant wellpreserved Glabrocingulum shells, together with a few 

other gastropods (USGS collns. 17194-PC, 25263-PC, 

25264-PC, 28610-PC):

Retispira ordinata n. sp.

Trepospira (Trepospira) baconi n. sp.

Glabrocingulum (Glabrocingulum?) hosei n. sp.

Deseretospira monilifera n. gen., n. sp. 

The brownish calcareous shale continues upward, 

but in the next 59 feet (18.0 m) it contains irregularly 

shaped calcareous concretions, larger and more 

sparsely scattered than the siliceous nodules below. 

Both the concretions and the shale contain abundant 

fossils, predominantly mollusks Paracravenoceras, 

Hematites, nautiloids, gastropods, and taxodont and 

pectenoid pelecypods (USGS collns. 15165-PC, 15166- 

PC, 17055-PC, 17186-PC, 23846-PC, 25262-PC, 

25284-PC, 28611-PC). Two species of gastropods occur 

here:

Glabrocingulum (Glabrocingulum) confusionense 

n. sp.

G. (G.?) hosei n. sp.

The same fossils are very sparse through the next 40 

feet (12.2 m) of shale, which contains a few scattered 

sandstone layers and earthy limestone beds. Three collections from this same general locality (USGS collns. 

17187-PC, 22856-PC, 25262-PC) include species from 

both intervals; all five species are represented.

The lowest fossiliferous bed assigned to the Cravenoceras hesperium Ammonoid Zone is 1,127 to 1,129 feet 

(343.5 to 344.1 m) above the base of the formation. A 

short distance higher stratigraphically, a 4.5-foot 

(1.4-m) bed of sandy limestone to calcareous sandstone 

containing well-preserved Cravenoceras aff. C. hesperium Miller and Furnish has its top 1,140 feet 

(347.5 m) above the base of the Chainman. In the 

Jensen Wash section, the only gastropods associated 

with the Cravenoceras hesperium Zone occur almost at 

the top of this zone. They are in a fossiliferous nodular 

shale, which weathers grayish orange to pale yellowish 

orange. Its yellowish tinge is distinctive in the weathered outcrop. The nodular shale is 16 feet (4.9 m) thick 

and is 1,620 to 1,636 feet (493.8 to 498.7 m) above the 

base of the Chainman. This is the same shale from 

which Sadlick and Nielsen (1963, p. 1100) collected the 

type specimens of Glabrocingulum quadrigatum

Sadlick and Nielsen and is the key level along which 

Gordon's measured section was offset to the northeast 

to complete the upper part in a better exposed area. 

Collections were made from weathered exposures of 

this unit, beginning at the Sadlick-Nielsen locality 

2-11 and continuing at intervals along the bed to the 

south-southwest for about half a mile (0.8 km). Gastropods from these collections (USGS collns. 

17056-PC, 17188-PC, 17189-PC, 17208-PC, 

17209-PC, 17219-PC, 25547-PC, 25550-PC) are 

listed below:

Euphemites nevadensis Gordon and Yochelson

Retispira jensenensis n. sp.

R. nolani Gordon and Yochelson

Straparollus (Euomphalus) intermedius Gordon 

and Yochelson

Trepospira (Trepospira) diadema n. sp.

Glabrocingulum (Glabrocingulum) quadrigatum 

Sadlick and Nielsen

Worthenia (Yochelsonospira) tenuilineata Girty

Stegocoelia (Stegocoelia) sp.

Pseudozygopleura (Pseudozygopleura) repenningi 

n. sp.

P. (P.)? lautan. sp.

lanthinopsis gandyensis n. sp.

/. sp. B?

Soleniscus sp. A

S. sp. B

The stratigraphically highest gastropod-bearing bed 

in the Chainman section at Jensen Wash is near the 

middle of a 56-foot (17.1-m), abundantly fossiliferous 

shale unit. Among numerous other brachiopods, the 

productoid Carlinia phillipsi (Norwood and Pratten) is 

common and characteristic. This unit is 2,067 to 2,123 

feet (630.0 to 647.1 m) above the base of the formation; 

the top of the unit is 80 feet (24.4 m) below the top of the 

Chainman Shale. The grayish-tan calcareous siltstone 

bed from which the gastropods were weathering out in 

some numbers was covered and could not be found in 

place, but as near as could be determined, the bed is 

roughly 110 feet (33.5 m) below the top of the formation. The gastropods from four collections made in this 

unit (USGS collns. 17059-PC, 17217-PC, 25548-PC, 

28612-PC) are as follows:

Euphemites sacajawensis C. Branson 

Bellerophon (Bellerophon) vespertinus Gordon and

Yochelson

Retispira stenopsis n. sp. 

Glabrocingulum (Ananias) seminudum Gordon

and Yochelson 

Euconospira desereti n. sp. 

Worthenia (Yochelsonospira) tenuilineata Girty 

Platyceras (Platyceras) cf. P. (P.) subrotundum

Snider
GASTROPOD ASSEMBLAGES AND RELATIONSHIP TO AMMONOID AND FORAMINIFERAL ZONES 21

SOUTHERN SLOPE OF BURBANK HILLS

The same faunal horizon as that collected at several 

localities along the top of the Cravenoceras hesperium 

Zone at Jensen Wash is recognized in the southern part 

of the Burbank Hills, where the belt of Chainman 

Shale outcrop approaches the valley between the Burbank Hills and the Needle Range. In a section measured by a petroleum company, a collection was made 

by John E. Welsh, formerly of Kennecott Copper Corporation, and presented to the USGS. The gastropods in 

this collection (USGS colln. 17310-PC) are:

Bellerophon (Bellerophon) welshi n. sp.

Retispira nolani Gordon and Yochelson

Trepospira (Trepospira) diadema n. sp.

Glabrocingulum (Glabrocingulum) quadrigatum 

Sadlick and Nielsen

G. (G.) binodosum Sadlick and Nielsen

Worthenia (Yochelsonospira) tenuilineata Girty

lanthinopsis gandyensis n. sp. 

The higher fauna is also present in this area. A collection made by Gordon in the SW V4 SE 1/4 SE 1/4 

sec. 29, T. 23 S., R. 18 W., includes several gastropods 

associated with rare Rhipidomella nevadensis (Meek). 

The locality is estimated as being 150 to 200 feet (45.7 

to 61.0 m) stratigraphically below the top of the Chainman Shale. The gastropods in this collection (USGS 

colln. 25319-PC) are:

Retispira nolani Gordon and Yochelson?

Glabrocingulum (Ananias) seminudum Gordon 

and Yochelson

Euconospira desereti n. sp.

Worthenia (Yochelsonospira) tenuilineata Girty

WESTERN PART OF BURBANK HILLS

A large area of Chainman Shale crops out in the 

vicinity of Red Pass in the northwestern part of the 

Burbank Hills. A collection made in the SE 1/4 SE 1/4 

NE V4 sec. 1, T. 22 S., R. 19 W,, on the slopes of a high 

mound of upper Chainman Shale contained Antiquatonia, Nuculopsis, and Cravenoceras hesperium Miller 

and Furnish in some abundance (USGS colln. 25318- 

PC). Associated with these are two species of gastropods characteristic of this ammonoid zone:

Glabrocingulum (Glabrocingulum) quadrigatum 

Sadlick and Nielsen

Worthenia (Yochelsonospira) tenuilineata Girty

NORTHERN END OF NEEDLE RANGE

The southernmost exposures of this belt of Chainman Shale outcrop, in the northern part of the Needle 

Range, have provided a few more specimens of gastropods. The lowermost of three gastropod-bearing beds 

was collected in the Paracravenoceras barnettense Ammonoid Zone in the NW 1/4 sec. 26, T. 25 S., R. 19 W., 

about 200 yards (182.9 m) west of the access road and 

just south of a gully along which a section was measured in the early 1950's by a petroleum company. 

From dark-gray silty limestone and shale, in association with the fossil coleoid Hematites barbarae Flower 

and Gordon, a species of bellerophontacean was collected (USGS colln. 15157-PC):

Retispira ordinata n. sp.

From the upper part of the Chainman Shale along 

the same line of section, two collections were made in 

two 2-foot (0.6-m) beds, 13 feet (4.0 m) apart stratigraphically, in the N. V2 sec. 27, T. 25 S., R. 19 W. The 

upper bed contains the ammonoid Richardsonites merriami (Youngquist). Gastropods present in the two beds 

(USGS collns. 15160-PC, 15161-PC) are:

Bellerophon (Bellerophon) needlensis n. sp.

Retispira sp. indet.

Glabrocingulum^ sp. indet.

Worthenia (Yochelsonospira) tenuilineata Girty

Straparollus (Euomphalus) sp.

GASTROPOD ASSEMBLAGES AND THEIR

RELATIONSHIP TO AMMONOID AND

FORAMINIFERAL ZONES

Analysis of the gastropod distribution data given in 

the preceding section of this report shows that eight 

distinct assemblages can be recognized in the Chainman Shale. Seven of these occur in stratigraphic succession; the eighth is a facies-controlled, carbonatefavoring faunule that shares the same stratigraphic 

zone as the penultimate mud-dwelling assemblage. 

One might consider the seven stratigraphically controlled assemblages as constituting a sequence of gastropod zones and propose formal names for them. However, as their ranges are identical with or very similar 

to those of previously named ammonoid zones and 

numbered foraminiferal zones, or within the bounds of 

these zones, no advantage would be realized. We prefer 

to consider the gastropod assemblages as integral components or representatives of the ammonoid zones and, 

similarly, of the equivalent foraminiferal zones.

The Bellerophontacea constitute approximately 

5 percent of the Chainman gastropod fauna; the 

Pleurotomariacea, by far the most abundant group, 

constitute nearly 89 percent. Tables 2 and 3 show the 

distribution of species of these two superfamilies in the 

Chainman Shale; table 4 shows many of the other taxa. 

The ammonoid and foraminiferal zones are used as a 

framework for these tables. The remaining seven gastropod superfamilies account for only 6 percent of the 

fauna. The gastropods and the assemblages in which
22 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH 

TABLE 2. Biostratigraphic distribution of bellerophontaceans in the Chainman Shale

Ammonoid 

zones

Richardsonites 

merriami

Cravenoceras 

hesperium

Paracra venoceras 

barnettense

Goniatites 

granosus

Goniatites 

multiliratus j

Goniatites 

americanus

Foraminifer 

zones

19

18

17

16s

16i

15

Sinuitina

S. (Sinuitina) crispa

S. (Vorticina) vortex

Euphemites

E. sacajawensis 

E. sp. A

E. cracens

E. nevadensis 

E. cf. E. sacajawensis

E. sp. indet.

E. sp. indet.

Bellerophon (Bellerophon )

B. (B.) vespertinus 

B. (B.)sp. A 

B. (B .) needlensis

B.(B.) welshi

B. (B .) vespertinus 

B.(B.) needlensis?

B. (B .) vespertinus

Retispira

R. stenopsis 

R. jensenensis

R . jensenensis 

R. nolani

R. ordinata

R. cincta

R. cf. R. textilis

they occur are discussed in more detail below, in stratigraphic order from bottom to top. For convenience in 

reference, each assemblage is designated by an informal name, generally that of the characteristic or 

predominant species. A discussion of the geographic 

distribution and stratigraphic correlation of these assemblages is based in part upon the locality information in the preceding section.

(1) Lunulazona nodimarginata assemblage. The 

lowest assemblage stratigraphically in the Chainman

Shale is known only at Granite Mountain, where it 

occurs in the upper part of the Goniatites americanus 

Zone, specifically 3 to 15 feet (0.9 to 4.6 m) above the 

marker bed. Its stratigraphic range corresponds closely 

with the lower part of Mamet Foraminifer Zone 16i. 

The nominal species was described originally as 

Pleurotomaria nodimarginata McChesney from near 

Batesville, Ark., where it occurs in the "so-called Boone 

Chert" (Girty, 1915b), which is part of the Moorefield 

Formation (Gordon and Kinney, 1944).

TABLE 3. Biostratigraphic distribution of common pleurotomariaceans in the Chainman Shale

Ammonoid 

zones

Richardsonites

merriami

Cravenoceras 

hesperium

Paracravenoceras 

barnettense

Goniatites 

granosus

Goniatites 

multiliratus /

Goniatites 

americanus

Foraminifer 

zones

19

18

17

16s

16i

Trepospira

T. (Trepospira) diadema

T. (Trepospira) diadema

T. (Trepospira) baconi 

T. (Trepospira) sp.

T. (Angyomphalus) regularis

Euconospira

E. desereti 

E. gradilis

Lunulazona.

L.?aff.L.?sablei 

L. utahensis

L. sadlicki

L. costata

L. nodomarginata

Glabrocingulum

G. (Ananias) seminudum 

G. (Glabrocingulum) sp. B 

G. (Glabrocingulum) binodosum

G. (Glabrocingulum) binodosum

G. (Glabrocingulum) quadrigatum 

G. (Glabrocingulum) quadrigatum

G. (Glabrocingulum) confusionense 

G. (Glabrocingulum?) hosei

G . (Glabrocingulum ) granulosum 

G. (Glabrocingulum) mephitifontis

G. (Glabrocingulum) sp. A
GASTROPOD ASSEMBLAGES AND RELATIONSHIP TO AMMONOID AND FORAMINIFERAL ZONES 23

TABLE 4. Biostratigraphic distribution of other pleurotomariaceans, eumphalaceans, neritaceans, and species from other superfamilies 

in the Chainman Shale

Ammonoid 

zones

R ickardsonites

mernami

Cravenoceras 

hesperium

Paracravenoceras 

barnettense

Goniatites 

granosus

Goniatites 

multiliratus

Goniatites 

americanus

Foraminifer 

zones

19

18

17

16s

/ 16i

15

Other pleurotomariacean 

genera

Worthenia tenuilineata

Neilsonia sp. 

Worthenia tenuilineata

Catazona rudilirata

Deseretospira monilifera 

Ptychomphalina burbankensis

Mourlonia venusta

Rhineoderma? sp.

Straparollus (Euomphalus)

S.(E.) sp.

S. (E.) nodibasis 

S. (E.) intermedius

S. (E.) intermedius

Naticopsis

N. (Naticopsis) confusionensis

N. (Jedria?) sp. 

N. (Naticopsis?) clinovata

N. (Naticopsis) confusionensis 

N. (N.) cf. N. (N.) genevievensis

Other superfamilies

lanthinopsis gandyensis 

Pseudozygopleura repenningi 

Stegocoelia sp. 

Pseudozygopleura? lauta

Anematina sp. 

Loxonema? sp.

Bellazona polita?

Bellazona polita

Loxonema sp. 

Bellazona bella

The following gastropod species make up this assemblage in west-central Utah:

Sinuitina (Vorticina) vortex n. sp.

Euphemites sp. indet.

Retispira cf. R. textilis (Hall)

Trepospira (Angyomphalus) regularis n. sp.

Mourlonia venusta n. sp.

Lunulazona nodimarginata (McChesney)

Glabrocingulum (Glabrocingulum) sp. A

Loxonema sp.

Bellazona bella (Walcott)

lanthinopsis? sp.

The same species of Retispira, Lunulazona, and Bellazona also were found by Walcott (1884) in what is 

now known as the Diamond Peak Formation in the 

Eureka mining district, Eureka County, Nev. These 

species occur in beds generally considered to be of late 

Meramecian age in both Nevada and Arkansas. This 

evidence supports the conclusions of Swann (1963, 

p. 18-21) regarding the type Chesterian section in 

western Illinois. Swann excluded the Aux Vases Sandstone and Levias Limestone Member of the Renault 

Formation from the type Chesterian because these 

units contain megafossils long regarded as Meramecian (Valmeyeran) in age. These two units belong in 

the lower part of Foraminifer Zone 16a of Mamet, according to Mamet and Skipp (1971, p. 1141, fig. 7). We 

regard the entire Goniatites americanus Zone, including the Lunulazona nodimarginata gastropod assemblage, as latest Meramecian in age.

(2) Lunulazona costata assemblage. The gastropods of the Lunulazona costata assemblage occur in 

the soft clay shale beds in the middle part of the Goniatites granosus Zone, the ammonoid zone directly 

equivalent to Mamet Foraminifer Zone 16s. The gastropods were most common in exposures at Granite 

Mountain, Juab County, from about half a mile 

(0.8 km) north of the measured section south to a point 

2.4 miles (3.8 km) southwest of the southern tip of Conger Mountain in Millard County, a distance of nearly 

33 miles (52.8 km). The gastropod species from this 

zone are:

Sinuitina (Sinuitina) crispa n. sp. 

Retispira cincta n. sp. 

Straparollid, gen. and sp. indet. 

Glabrocingulum (Glabrocingulum) granulosum n.

sp.

G. (G.) mephitifontis n. sp. 

Lunulazona costata Sadlick and Nielsen 

Bellazona polita n. gen., n. sp.

A similar faunule, associated with ammonoids of the 

Goniatites granosus Zone, was also recognized in 

Nevada, about 1 mile (1.6 km) north of the ruins of 

Pogues Station on the old Pony Express route, not far 

from the southwestern corner of White Pine County. 

This occurrence is approximately 117 miles (187.2 km) 

due west of Skunk Spring, Millard County, Utah, one of 

the localities where members of this assemblage are 

present.
24 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

With the possible exception of Bellazona polita, all 

the species listed above are restricted to this zone. A 

specimen of B. polita was collected from a limestone bed 

containing Cravenoceras kingi (Hall and Whitfield), a 

bed that immediately overlies the shale of the Goniatites granosus Zone in the northern part of the Bishop 

Springs anticline. This specimen might have been reworked.

(3) Lunulazona sadlicki assemblage. The lowest 

assemblage of early Namurian age is most characteristically represented in an impure limestone bed at the 

Jensen Wash section, Burbank Hills, Utah. The bed is 

in the lower part of the Paracravenoceras barnettense 

Zone, this zone being directly equivalent to Mamet 

Foraminifer Zone 17. Gastropods 457 to 534 feet (139.3 

to 162.8 m) above the marker bed in the measured 

section at Granite Mountain also seem to belong to this 

assemblage. The assemblage contains the following 

species:

Euphemites sp. A?

Trepospira (Trepospira) sp.

Ptychomphalina burbankensis n. sp.

Lunulazona sadlicki n. sp.

Cinclidonema sp.

The holotype of Lunulazona sadlicki is from 3.5 miles 

(5.6 km) north of Wendover, Utah, 0.3 miles (0.5 km) 

northeast of Leppy Peak in Elko County, Nev. It occurs 

there with Ptychomphalina sp. and therefore seems to 

represent the same assemblage as the Jensen Wash 

occurrence, 133 miles (212.8 km) farther south and 

14 miles (22.4 km) farther east.

(4) Glabrocingulum hosei assemblage. Stratigraphically higher, but within the same goniatite zone, 

the 20 feet (6.1 m) of soft shale containing abundant 

siliceous nodules is crowded with specimens of 

Glabrocingulum hosei in the Jensen Wash measured 

section. The gastropods present in this assemblage are:

Retispira ordinata n. sp.

Trepospira (Trepospira) baconi n. sp.

Glabrocingulum (Glabrocingulum?) hosei n. sp.

Deseretospiramonilifera n. gen., n. sp. 

This assemblage has not yet been widely recognized in 

the region, in part because in some areas, such as 

Skunk Spring and Granite Mountain, the beds of the 

Paracravenoceras barnettense Zone are impure spiculitic shale, not a suitable habitat for most megafossils. Another possible reason for the scarcity of this 

assemblage is the faults that are common in areas 

where the gastropod-bearing beds are extensive, as in 

the Bishop Springs anticline; these faults may be responsible for the absence of the beds containing this 

particular assemblage. The presence of Retispira ordinata n. sp. at a locality in the Needle Range suggests 

that this assemblage may be represented there.

(5) Glabrocingulum confusionense assemblage. At 

Jensen Wash, approximately the uppermost 100 feet 

(30.5 m) of the Paracravenoceras barnettense Zone contains two glabrocingulums in some abundance. These 

are:

Glabrocingulum (Glabrocingulum) confusionense

n. sp.

G. (G.?) hosei n. sp.

These occur roughly in a 60 to 40 ratio, respectively. 

The beds that contain them in the Bishop Springs anticline area are exposed mostly in fault slices, but within 

these slices, the beds are in normal sequence; the assemblage is cut off abruptly at the base of the overlying 

Cravenoceras hesperium Zone. These gastropods are extremely useful in this area, together with the associated tela (guardlike hard parts) of the coleoid Hematites, for recognizing the upper part of the 

Paracravenoceras barnettense Zone. However, as at 

Skunk Spring and Granite Mountain, this part of the 

section consists almost exclusively of spiculitic shale in 

which fossils of any description are virtually absent.

This two-species assemblage has not been seen outside the west-central Utah region. In the Pancake 

Range in White Pine County, Nev., an entirely different fauna occupies the upper part of the Paracravenoceras barnettense Zone. The presence of this fauna of 

Worthenia (Yochelsonospira) tenuilineata Girty together with Paracravenoceras barnettense at a locality 

in the NE V4 sec. 21, T. 18 N., R. 56 E., on the eastern 

flank of the range, suggests a stratigraphic position at 

or near the top of the zone. Taxa present here are 

Euphemites, Bellerophon (Bellerophon), Retispira, 

Straparollus (Euomphalus), Trepospira (Trepospira), 

Glabrocingulum (Ananias), Worthenia (Worthenia), 

Worthenia (Yochelsonospira), Deseretospira, and 

Meekospira?. The coleoid Hematites is also present. 

This distinctively different and apparently geographically restricted Nevada fauna in the upper part of the 

Paracravenoceras barnettense Zone is in contrast to the 

more widely dispersed gastropod faunas below it.

(6A) Glabrocingulum quadrigatum assemblage. 

The Glabrocingulum quadrigatum assemblage is found 

throughout the Cravenoceras hesperium Zone, which 

coincides with the lower and major part of Mamet 

Foraminifer Zone 18. The stratigraphic range of the 

nominal species coincides with that of the ammonoid 

zone. This assemblage is recognized from Granite 

Mountain southward to the southern slope of the Burbank Hills. The gastropod fauna is particularly abundant in the upper part of the ammonoid zone. In the 

Burbank Hills, the gastropods are restricted to a single 

15-foot (4.6-m) unit of gray to tan shale at the top of the 

Cravenoceras hesperium Zone, but in the Bishop 

Springs anticline, Foote Range, and Granite Mountain
GASTROPOD ASSEMBLAGES AND RELATIONSHIP TO AMMONOID AND FORAMINIFERAL ZONES 25

areas, they occur throughout the zone. Even in these 

more northern areas, however, the abundance of species is greater in the upper part of the zone.

The gastropod species of this assemblage include the 

following:

Euphemites nevadensis Gordon and Yochelson

E. sacajawensis C. C. Branson

Bellerophon (Bellerophon) welshi n. sp.

B. (B.) needlensis n. sp.

B. (B.) vespertinus Gordon and Yochelson

Retispira nolani Gordon and Yochelson

R. jensenensis n. sp.

Trepospira (Trepospira) diadema n sp.

Glabrocingulum (Glabrocingulum) quadrigatum

Sadlick and Nielsen

Worthenia (Yochelsonospira) tenuilineata Girty 

Neilsonia sp.

Stegocoelia (Stegocoelia?) sp. 

Straparollus (Euomphalus) intermedius Gordon

and Yochelson 

Anematina sp. 

Loxonema sp. 

Pseudozygopleura (Pseudozygopleura) repenningi

n. sp.

P. (P.?)lautan. sp. 

P. sp.

lanthinopsis gandyensis n. sp. 

Soleniscus sp. A 

S. sp. B 

Meekospira sp.

In addition to these species, a single specimen of 

Glabrocingulum (Glabrocingulum) binodosum Sadlick 

and Nielsen came from the southern slope of the Burbank Hills in a collection that was made by a petroleum 

company and donated to the USGS (USGS colln. 

17310-PC). Because this species is typical of the next 

higher assemblage and because we have not been able 

to verify its occurrence elsewhere in the Glabrocingulum quadrigatum assemblage, it has not been included 

in the list above.

This assemblage is found in shale and in impure 

limestone beds in shale sequences. It occupies the same 

ammonoid and foraminiferal zone as the assemblage 

that follows, the two being differentiated mainly by the 

lithologic facies in which they occur.

(6B) Catazona rudilirata assemblage. The Catazona rudilirata assemblage is best represented in the 

thick lenticular limestone deposit (Willow Gap Member of Sadlick, 1966) at Skunk Spring and Browns 

Wash; it also has been recognized in the section at 

Granite Mountain. Characteristic species in this assemblage, in addition to the nominal one, include Straparollus (Euomphalus) nodibasis n. sp. and several 

forms of Naticopsis. Ammonoids are extremely rare in

this facies; the only one found, at Skunk Spring, was 

identified tentatively as Cravenoceras hesperium 

Miller and Furnish. Foraminifera of Mamet's Zone 18 

occur throughout the section that contains this faunal 

assemblage. Gastropods of this assemblage are listed 

below:

Euphemites nevadensis Gordon and Yochelson?

Bellerophon (Bellerophon) sp. indet.

Retispira sp. indet.

Bay lea? sp.

Dictyotomaria sp.

Catazona rudilirata Gordon and Yochelson

Straparollus (Euomphalus) nodibasis n. sp.

S. (E.) intermedius Gordon and Yochelson

Strophostylus nevadensis Gordon and Yochelson

Naticopsis (Naticopsis) confusionensis n. sp.

N. (N.) cf. N. (N.) genevievensis Meek and Worthen

N. (N.?) clinovata n. sp.

N. (Jedria?) sp.

Pseudozygopleura (Stephanozyga) claviger n. sp.

Bulimorpha sp.

Soleniscus? sp.

Girtyspira circumsecta n. sp.

High-spired tiny gastropods, gen. and sp. indet.

Coarse silicification, particularly of the bellerophontaceans and subulitaceans, precludes the identification 

of many specimens to species or even to genus. Much 

better preserved examples of the gastropods of this assemblage occur in the Diamond Peak Formation in the 

northern part of the White Pine Range, White Pine 

County, Nev. The writers have described 26 species of 

gastropods from a single bed in the NE 1/4 sec. 28, 

T. 19 N., R. 58 E., and have noted the similarity of this 

faunule to that of the limestone facies at Willow Gap in 

the Confusion Range (Gordon and Yochelson, 1983).

The gastropods found in the Cravenoceras hesperium 

Zone of the Confusion Range account for about half the 

species known from the Chainman Shale. The gastropod species recorded from the two lithic facies in this 

region, combined with those of the same ammonoid 

zone in Nevada described previously (Gordon and 

Yochelson, 1983) but not yet identified in western 

Utah, give a grand total of 47 gastropod species described and illustrated from this zone in the Great 

Basin.

(7) Glabrocingulum binodosum assemblage. The 

beds overlying the Cravenoceras hesperium Zone occupy all but the basal 15 feet (4.6 m) of the Jensen 

Member of Arnold and Sadlick (1962), the type locality 

of this member being at Jensen Wash in the Burbank 

Hills; because of incomplete publication, however, the 

USGS has not recognized this member. These beds also 

include the Rhipidomella nevadensis Zone of Sadlick 

(1955, p. 54). In the lower part of this brachiopod zone
26 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

is a bed containing the ammonoid Richardsonites merriami (Youngquist). What is believed to be a single bed 

in the same stratigraphic position, and containing this 

ammonoid, is present in the Foote Range, Indian Pass, 

Coyote Pass, and Needle Range areas.

The gastropods of these uppermost beds of the Chainman Shale include some of the species that occur in the 

Cravenoceras hesperium Zone, along with others that 

are not known in the lower parts of the Chainman 

Shale, at least in west-central Utah. Along the east 

slope of the Foote Range and southward to Skunk 

Spring, the most characteristic species of this part of 

the section is Glabrocingulum (Glabrocingulum) 

binodosum Sadlick and Nielsen, commonly found 

about 20 to 25 feet (6.1 to 7.6 m) above the Richardsonites merriami beds. Farther south, at Coyote Pass, 

Jensen Wash, and the southern slope of the Burbank 

Hills, G. (Glabrocingulum} binodosum seems to have 

been replaced laterally by G. (Ananias) seminudum 

Gordon and Yochelson. For some reason, not yet fully 

explained, G. (Ananias) seminudum, which is a fairly 

common component of the Catazona rudilirata assemblage in the White Pine Range, Nev., is always found 

higher in the section in the Confusion Range and Burbank Hills, Utah.

The species found in the upper part of the Chainman 

Shale, between the top of the Cravenoceras hesperium 

Zone and the top of the formation, are listed below:

Euphemites sp. A

E. cracens n. sp.

E. sacajawensis C. C. Branson

Bellerophon (Bellerophon) sp. A

B. (B.) needlensis n. sp.

B. (B.) vespertinus Gordon and Yochelson

Retispira stenopsis n. sp.

Trepospira (Trepospira) diadema n. sp.

Lunulazona cf. L. sablei (Yochelson and Dutro)

Glabrocingulum (Ananias) seminudum Gordon 

and Yochelson

G. (Glabrocingulum) binodosum Sadlick and 

Nielsen

G. (G.)sp. B

Euconospira desereti n. sp.

E. gradilis n. sp.

Worthenia (Yochelsonospira) tenuilineata Girty

Straparollus (Euomphalus) sp.

S. (E.) intermedius Gordon and Yochelson

Naticopsis (Naticopsis) confusionensis n. sp.

Soleniscus sp. B

GASTROPODS AS GUIDE FOSSILS

Gastropods generally have been neglected in studies 

of Carboniferous biostratigraphy. The genera are relatively long ranging. The common impression has been 

that the species also are long ranging. Perhaps the 

most significant result of the present study is to show 

that, as guide fossils at the species level, gastropods can 

be almost as useful as foraminifers, ammonoids, or 

conodonts. Although we have chosen to integrate the 

gastropod assemblages with established ammonoid and 

foraminiferal zones, a zonal framework based upon the 

gastropods alone could have been established.

Within the framework of the Mamet foraminiferal 

zonation, so far as can now be determined, all but three 

of the gastropod species are restricted to a single zone. 

Within the framework of the ammonoid zones, most of 

the gastropod species also are restricted to one or another zone; three separate gastropod assemblages have 

been recognized within the Paracravenoceras barnettense Zone (=Mamet's Foraminifer Zone 17). Although some gastropod species range from the 

Cravenoceras hesperium Zone into the beds above that 

contain Richardsonites merriami and the brachiopod 

Rhipidomella nevadensis, both of these ammonoid assemblages occur within the worldwide Eumorphoceras 

bisulcatum (E2) Ammonoid Zone.

DIVERSITY AND FACIES CONTROL

In general, gastropods in the Chainman Shale show 

much greater diversity than do ammonoids. The ratio 

of gastropod species in the Chainman Shale to ammonoid species is about 8 to 3. Ammonoids are found 

preferentially in basinal sedimentary rocks, such as 

dark-gray mudstone and impure limestone; gastropods 

also occur in those rocks. Ammonoids are very rare in 

shallow-marine limestone in a shoal or shelf environment; these environments normally are populated with 

brachiopods, bryozoans, and corals. Gastropods, on the 

other hand, are present in shelf and shoal limestone, 

locally in great numbers. Generally, they are represented by different species from those found in the basinal sedimentary rocks not far away. The diversity of 

species controlled by facies is well illustrated by the 

two different assemblages found in the Cravenoceras 

hesperium Zone. The Glabrocingulum quadrigatum assemblage occurs in mudstone and impure limestone, 

whereas the Catazona rudilirata assemblage occurs in 

a massive fine-grained limestone; both assemblages 

lived at the same time in the shallow shoal environment.

Where the two different lithic facies approach one 

another, the two faunal assemblages may replace one 

another. An example is found in the Granite Mountain 

section, where the upper part of the Chainman is more 

calcareous than in sections farther south. At 942 to 943 

feet (287.1 to 287.4 m) above the limestone marker bed,
SYSTEMATIC PALEONTOLOGY 27

the Glabrocingulum quadrigatum assemblage is present. 

From 1,018 to 1,054 feet (310.3 to 321.3 m) above the 

marker bed, the Catazona rudilirata assemblage is present. At 1,075 to 1,078 feet (327.7 to 328.6 m) above the 

marker bed, the Glabrocingulum quadrigatum assemblage reoccurs, but associated with it are two species, 

Strophostylus cf. S. nevadensis n. sp. and Naticopsis 

(Naticopsis?) clinovata n. sp., that are more typical of the 

Catazona rudilirata assemblage. This association 

suggests that a delicate balance between the two facies 

existed at this locality. It also indicates that the gastropods were sensitive to slight changes in subtrate and 

water chemistry; therefore, they may be more reliable in 

identifying facies changes than the lithofacies alone would 

be.

SYSTEMATIC PALEONTOLOGY

[In the list of occurrences given for each species after its 

description and discussion, a question mark preceding 

the locality number questions the identification of the 

species at that locality, not the locality itself.]

Phylum MOLLUSCA

Class GASTROPODA

Subclass PROSOBRANCHIA

Order ARCHAEOGASTROPODA

Suborder BELLEROPHONTINA

Superfamily BELLEROPHONTACEA

Family SINUITIDAE

Subfamily BUCANELLINAE

Genus SINUITINA Knight, 1945

Discussion. When the genus Sinuitina was first 

proposed (Knight, 1945, p. 333), only the type species 

was included, and emphasis was placed on a cordiform 

whorl profile as one of the generic features. In the two 

decades that followed, several other species were described or assigned to it. In spite of the small number of 

species within this genus, these species clearly belong 

in two groups. We hereby provide subgeneric names for 

these groups to emphasize features that otherwise 

might be ignored when additional species are described.

Our impression is that specimens of Sinuitina are 

rare, especially in comparison with other late Paleozoic 

bellerophontaceans; throughout the geologic range of 

this fossil genus, it is uncommon. Nevertheless, a species of each subgenus occurs in the Chainman Shale, 

providing the incentive to comment on divisions within 

the genus that are based mainly on differences in whorl 

profile. Although the subgeneric forms tend to intergrade, the two Chainman species seem to represent 

extremes of both shapes.

Subgenus S. (SINUITINA) Knight, 1945

Diagnosis. Whorl profile broadly helmet-shaped, 

having a prominent somewhat flattened median crest 

which bears a pseudoselenizone. Collabral ornamentation prominent.

American Mississippian species of Sinuitina (Sinuitina). 

crispa, n. sp. 

nudidorsa Rollins, 1975 

venata (Girty), 1910 (Oxydiscus)

Sinuitina (Sinuitina) crispa n. sp.

Plate 1, figures 1-6

Diagnosis. Moderately involute helmet-shaped 

bellerophontacean, having broad V-shaped sinus centering on raised flattened median dorsal crest.

Description. Shell phaneromphalus, bilaterally 

symmetrical, umbilicus occupying slightly more than 

one-fourth length of conch. Earliest whorls unknown. 

Whorl profile helmet shaped, dorsum formed by raised 

gently convex ridge. Umbilicus deep, having prominent, narrow, carinate, flat shelf midway between suture and umbilical shoulder, so that each whorl is 

stepped; inner part of umbilical wall steep and concave, 

outer part steep and convex; umbilical shoulder 

strongly rounded. Periphery about one-third distance 

from umbilical shoulder to dorsum; flanks convex, 

curving inward and becoming concave near dorsum, 

then curving abruptly into gently convex dorsum. 

Aperture sinuate, total depth of sinus being about oneeighth of circumference of body whorl; deepest and 

most strongly curved part of sinus lying within dorsum, 

appearing as prominent pseudoselenizone.

Growth lines obscure in deepest part of umbilicus, 

where they are closely spaced and curving from 

opisthocline to prosocline, becoming stronger on umbilical shelf, and prominent on outer wall of umbilicus, 

where they are orthocline and continue straight across 

periphery; beyond periphery, growth lines curve gradually prosocline, degree of curvature increasing uniformly in rough logarithmic curve, uninterrupted by 

sides of dorsal zone, where they converge at angle near 

80°; within pseudoselenizone, growth lines recurving 

sigmoidally, meeting in boardly acute angle at single 

discontinuous spiral lira, which bisects pesudoselenizone. Ornamentation of prominent raised rounded colabral costae, maintaining fairly uniform thickness 

and height from upper part of umbilical wall to sinus, 

widely and uniformly spaced except along sides of crest, 

where they are closer together; number of riblets on 

crest increases slightly by local intercalation on outer 

flanks.

Dimensions. Measurements (in mm) of holotype 

and two paratypes from type locality are as follows:
28 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

USNM 210915

Length ----------------- 21,4

Width------------------- 11.5

Diameter of umbilicus - - - 16.5

210916 210917

13.6 13.3

6.5 8.0

3.7 3.6

Discussion. ~The primary types include six specimens. Two of them, which are incomplete, come from 

the Goniatites granosus Zone near Skunk Spring in the 

Confusion Range (USNM 210919, 210920). The better 

lot is from the same ammonoid zone in the Chainman 

Shale on the western side of the Pancake Range, in the 

NW V4 SW V4 sec. 1 (unsurveyed), T. 15 N., R. 54 E., 

about 1 mile (1.6 km) north-northeast of Pogues Station ruins, White Pine County, Nev. The holotype and 

three paratypes are from this locality (USGS colln. 

22961-PC).

This species is readily distinguished from Sinuitina 

(Vorticina) vortex n. sp. and from other shells of that 

subgenus by its helmet-shaped whorl and raised dorsal 

crest, by the small carinate shelf within the umbilicus, 

and by the prominence of the collabral ornamentation 

over the dorsal region. It is most similar to the type 

species of Sinuitina, S. cordiformis (Newell), from the 

upper part of Missourian Series in northern Oklahoma, 

which it resembles in general shape and prominent 

collabral ornamentation. In S. cordiformis, however, 

the dorsum is not so highly raised and is more narrowly 

rounded than in our Chainman form, and the collabral 

costae are less regularly curved and more widely 

spaced over the flanks and increase in number dorsally, 

in contradistinction to the Utah species.

Types. Holotype USNM 210915; paratypes USNM 

210916-210920.

Occurrence and number of specimens. USGS collection 25261-PC (2), Millard County.

Subgenus S. (VORTICINA) n. subgen.

Type species Sinuitina anneae Conkin, 1957

Diagnosis. Whorl profile a pointed arch; dorsum 

bluntly rounded, bisecting pseudoselenizone. Collabral 

ornamentation prominent on inner flanks, reduced on 

outer flanks and dorsum.

American Mississippian species of Sinuitina (Vorticina). 

anneae Conkin, 1957 

cyrtolites (Hall), I860 (Bellerophon?) 

rugosiuscula (Winchell), 1862 [1863] (Bellerophori) 

taeniata (Winchell), 1862 [1863] (Bellerophon) 

vortex n. sp.

Discussion. Because of the rarity of the Chainman 

Shale species and the remoteness of its type locality, a

1 Outer whorl slightly contorted; average of measurements of both sides.

niore easily accessible and well-known species has been 

designated as the type of this subgenus. S. (V.) anneae 

is from the Lower Mississippian New Providence Shale 

of Kentucky. We examined Conkin's types in the 

USNM. His description and illustrations accurately 

portray the key features of S. (Vorticina) and need no 

amplification. Sinuitina keytei Yochelson, from the 

Permian Leonard Formation of west Texas, S. (V.) vortex n. sp., from the Chainman Shale, Bellerophon rugosiusculus Winchell, from the Marshall Formation of 

Michigan, and Bellerophon? cyrtolites Hall, from the 

Rockford Limestone of Indiana, are included in this 

subgenus. From the limited fossil record of Sinuitina , it 

seems that S. (Vorticina) has a longer stratigraphic 

range than the typical subgenus.

As indicated by our use of subgenera, S. (Vorticina) 

does intergrade with the typical subgenus. However, 

the whorl profile in the form of a pointed arch distinguishes it from the broader shell of S. (Sinuitina).

Sinuitina (Vorticina) vortex n. sp.

Plate 1, figures 7-11

Diagnosis. Narrowly sinuate bellerophontacean 

having whorls that form blunt pointed arch in cross 

section; riblets largely confined to lower flanks at maturity.

Description. Shell phaneromphalus, moderately 

involute, umbilicus occupying slightly more than onefourth of conch length. Umbilicus imperfectly known, 

but having narrow revolving angulation low on umbilical wall with steep slopes at either side. Whorl profile 

broadly and bluntly lenticular; periphery relatively 

close to umbilical margin; flanks above periphery arch 

convexly inward to narrow rounded dorsum. Shell 

without obvious ontogenetic change in profile other 

than narrowing of shell from moderately young to mature growth stages. Growth lines sigmoidal and 

slightly prosocline within umbilicus, changing curva: 

ture centering on umbilical angulation, orthocline 

from outer part of umbilical slope to periphery, then 

curving strongly and smoothly prosocline to dorsum, 

joining there forming simple V-shaped sinus, which in 

depth approximates one-eighth of body whorl length. 

Shell ornamented by widely spaced, low but distinct, 

riblets, prominent below periphery, but nearly obsolete 

on upper flanks at maturity.

Dimension. Measurements (in mm) of the holotype 

and paratype are as follows: length 15.0 and 24.5; 

width 10.5 and 14.0; diameter of umbilicus (approximate) 4.0 and 7.5.

Discussion. This species is based upon two specimens from the Goniatites americanus Zone in the section at Granite Mountain. The length/width ratios for
SYSTEMATIC PALEONTOLOGY 29

the two specimens are 0.57 and 0.70, respectively, indicating a narrowing of the shell during growth.

The inflated, smoothly arched cross section, similar 

in shape to the so-called Gothic arch, is distinctive in 

this species and serves to distinguish it from Sinuitinas 

of the typical subgenus. In addition to the differences in 

conch shape that distinguish S. (Sinuitina) crispa n. 

sp., several differences in ornamentation can be noted. 

Not only is the collabral ornament continuous across 

the dorsum at maturity in S. (S.) crispa, but at comparable positions on the whorl flanks, the riblets in S. 

(V.) vortex are lower, finer, and more closely spaced. 

The small angulation within the umbilicus of this species is not nearly so prominent as the carinate shelf in 

S. (S.) crispa.

In comparing this species of S. (Vorticina ) with other 

members of the subgenus, the Permian form S. (V. ) 

keytei Yochelson is far more compressed. More similar 

in shape is S. (V. ) anneae Conkin, from the New Providence Shale of Kentucky, but that species also is somewhat more narrowly lenticular and is much smaller; 

growth lirae on the upper part of the flanks of that 

species are less obscure and are geniculate at the periphery, rather than swept backward as in S. (V.) vortex. These last two features also differentiate S. (V.) 

vortex from S. (S. ) venata (Girty), from the Fayetteville 

Shale of Arkansas.

We examined unpublished notes of G. H. Girty on 

H. W. Winchell's material from the Marshall Formation of Michigan. Girty reexamined the type specimens 

and prepared drawings. We can determine from this 

material that Bellerophon rugosiusculus Winchell and 

B. rugosiusculus taeniatus are representatives ofSinuitina (Vorticina}. The type lots for this species and subspecies may include more than one species. The holotype of S. (V. ) rugosiusculus may be differentiated from 

S. (V. ) vortex by its broader dorsum and the cancellate 

sculpture on its flanks.

Bellerophon? cyrtolites Hall, from the "Goniatite 

limestone," overlying the main part of the Rockford 

Limestone, at Rockford, Ind., is also transferred to this 

subgenus. In spite of the long synonymy that accompanies this species (see Yochelson and Saunders, 1967, 

p. 238), it is a poorly known form. The type was never 

figured and may be lost. Illustrations of topotypes by 

Meek and Worthen (1866a, pi. 14, figs. 8a, b) do not 

show all the critical features but do indicate a strongly 

angulated dorsum having flattened sides that form 

nearly a right angle at the crest. This shape distinguishes Hall's species from S. (V. ) vortex.

Types. Holotype USNM 210921; paratype USNM 

210922.

Occurrence and number of specimens. USGS collection 17018-PC (2), Juab County.

Subfamily EUPHEMITINAE 

Genus EUPHEMITES Warthin, 1930

Discussion. Our study of the bellerophontaceans of 

the Chainman Shale demonstrates that we must 

reevaluate our concept of the characters by which species are differentiated in Euphemites. We will discuss 

these characters in the order of their importance as we 

now view them.

The first specific character is shell shape. Most gastropods grow uniformly; allometric growth or ontogenetic change is the exception rather than the rule. This 

is essentially true of the bellerophontaceans; wide species tend to remain wide during growth and narrow 

species, narrow. Almost no attention has been given to 

ontogenetic change in defining species. Studies of 

many species of Euphemites have convinced us that 

whorl profile is probably one of the most important 

features for differentiating species. Reliance on shape, 

nevertheless, must be tempered with an appreciation 

for possible change during growth. In the Chainman 

species Euphemites sp. A, juvenile specimens possess 

umbilical depressions, whereas in mature individuals, 

the depressions have disappeared and the profile is 

smoothly rounded. In addition to changes in the umbilical area, smaller individuals are slightly less inflated 

on the flanks than are larger ones. Geniculation as the 

result of change in the logarithmic growth spiral is an 

important feature in some members of this genus but 

apparently does not occur in any of the species described from the Mississippian rocks of North America.

Second in importance to shape is the ornamentation 

surrounding the umbilical region. In Euphemites sp. A, 

the lirae remain fairly constant and rarely are interrupted in the columellar area. However, in Pennsylvanian species of similar shape, such as E. blaneyanus 

(McChesney) or E. vittatus (McChesney), pustules, 

nodes, or short lirae en echelon low on the flanks are 

characteristic.

Third in importance in differentiating species of Euphemites is the number, strength, and spacing of the 

longitudinal lirae that characterize this genus. Because the number of lirae is an easily observable character, it has been used widely in species differentiation, 

but this character is rather variable. In Euphemites sp. 

A, we find a range in number of lirae from 22 to 28. 

Much of the difference in number seems to be individual variation, but a tendency also exists during the 

growth of individuals toward some irregularity in the 

development of lirae. Most commonly, new lirae are 

added near the umbilical region, but, occasionally, a 

single lira may die out or be inserted locally on the 

dorsum. Although the number of lirae may increase 

with growth, within E. sp. A, we have observed small
30 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

specimens having 28 lirae and much larger ones having only 23 lirae.

Spacing of the lirae also may be a deceptive character. The spacing is a function partly of the shape of the 

shell and partly of the shape of the lirae. Because of 

this, one species may have not only more lirae but more 

widely spaced lirae than another species. Euphemites 

incarinatus Easton, from the Pitkin Limestone of 

Arkansas, is ornamented by more than 40 lirae, but 

these are exceedingly fine and, relative to their size, 

they are more widely spaced than those of E. sp. A.

We regard, therefore, the number, strength, and 

spacing of the longitudinal lirae as useful but not infallible specific characters. A general study of Euphemites 

might show some developmental trends involving the 

lirae, but our brief review of Mississippian and 

Pennsylvanian species has not demonstrated any yet. 

Perhaps if lineages within the genus were established 

on whorl profile and shape, general patterns of ornamentation might then be recognized.

The least important character in differentiating species of Euphemites, involves the selenizone, its width, 

elevation, and its relationship to the slit and apertural 

margin. Like the liration, all these features are variable. The number of lirae on the dorsum that occupy 

the selenizone width commonly may vary by one in the 

same population. The fine lira bordering either side of 

the selenizone is not always continuous with one of the 

lirae ornamenting the main part of the dorsum; on 

some specimens, it may be present between two more 

prominent dorsal lirae. It would seem, therefore, that 

the number of lirae within the selenizone area varies 

with spacing of lirae over the dorsum, but the relative 

width of the selenizone remains fairly constant. Elevation of the selenizone also seems to vary; some specimens from a single locality have the selenizone elevated and others do not. On Euphemites randolphensis 

(Weller), however, the selenizone occupies a generally 

elevated area. On most Euphemites, the slit is relatively short; on some, it may approximate one-sixth of 

a whorl. 

American Mississippian species of Euphemites. 

compressus Elias, 1958 [probably not recognizable]

cracens n. sp.

galericulatus (Winchell), 1862 (Bellerophon) [synonym: Bellerophon nautiloides Winchell, 1862]

incarinatus Easton, 1943

tlentiformis (S. Weller), 1916 (Euphemus)

nevadensis Gordon and Yochelson, 1983

randolphensis (S. Weller), 1920 (Euphemus)

sacajawensis C. Branson, 1937

sedaliensis (Miller and Gurley) 1896 (Bellerophon)

subglobosus Hyde, 1953

Ten bellerophontacean species described from 

Mississippian rocks in the United States belong in this

genus. Five of them occur in the Lower Mississippian. 

One of the lowest stratigraphically is Euphemites subglobosus Hyde, from the Byer Member of the Logan 

Formation in Ohio. This species is recognized by its 

subglobose shape, its diameter/width ratio being 0.75; 

by its flat sides without umbilical depressions; and by 

its longitudinal sculpture of 25 to 30 lirae in mature 

shells. The selenizone is raised near the aperture and 

marked by a faint median ridge; the slit is shallow.

Much less well understood is Bellerophon sedaliensis 

Miller and Gurley, from the Chouteau Limestone of 

Missouri, the type lot of which was interpreted by 

Branson as containing two distinct species. According 

to Branson (1938, p. 103, 104), one of the two syntypes 

figured by Miller and Gurley (1896, p. 21, pi. 3, figs. 9, 

10) is an internal mold of Bellerophon blairi Miller and 

Gurley. The other has longitudinal lirae, and we consider it to be a Euphemites. It is the one figured by 

Miller and Gurley (1896) on their plate 13, figure 13 

and by Branson (1938) on his plate 14, figure 14. A 

specimen from Cooper County, Mo. (USNM 66828), 

14 mm in length and 10 mm in width, was collected and 

identified as E. sedaliensis (Miller and Gurley) by 

Charles Schuchert. This specimen shows that the mature shell has a slightly galeiform shape, having a narrow dorsum somewhat flattened on top, and rather 

widely spaced longitudinal lirae. This shape is similar 

to that of E. galericulatus (Winchell).

Euphemites galericulatus (Winchell) and E. nautiloides (Winchell), both from the Marshall Formation 

of Michigan, are inadequately known by present standards, and the types were never figured. We have examined unpublished notes of G. H. Girty, which record his 

restudy of Winchell's material. Girty concluded that E. 

nautiloides was based upon poorly preserved specimens 

of E. galericulatus, which is somewhat variable in 

width. If so, the attempt by Hyde (1953, p. 322, 323, 

pi. 46, figs. 21-26) to differentiate the two species according to Winchell's measurements, and the comments of Elias (1958, p. 2) on Hyde's probable mixture 

of two species are inapplicable. As we now understand 

this species, E. galericulatus includes specimens having a galeiform shape and many lirae, those lirae on 

the flanks being irregular and oblique to those on the 

principal part of the shell. Herrick's (1888, pi. 2, fig. 34; 

pi. 9, figs. 32a, b) illustrations of E. galericulatus add 

little to our understanding of the species. Furthermore, 

the specimens illustrated by Butts (1941, pi. 125, figs. 

19-22) as E. galericulatus and deposited in the USNM, 

specimens that we have examined, are not correctly 

identified. At least one has ornamentation like that of 

Retispira; all are specifically indeterminate.

The rest of the species of Euphemites are from the 

Upper Mississippian. The one Meramecian form, Euphemites lentiformis (Weller), from the Ste. Genevieve
SYSTEMATIC PALEONTOLOGY 31

Limestone in Illinois, is small, subdiscoidal, lenticular 

in cross section, has a very narrow dorsum, and is ornamented by very faint lirae. It is strikingly different 

from other species of Euphemites and probably should 

not be included in the genus.

The earliest Chesterian species is E. randolphensis 

(S. Weller), from the basal part of the Okaw Limestone 

of Illinois; it has a small- to medium-sized subglobose 

shell generally having a slightly raised mid-dorsum, 

bulging flanks, and well-developed umbilical depressions, all of which tend to give the whorl a trilobed cross 

section. On some specimens, this trilobation is accentuated by a pair of swellings, one on each flank, on the 

smooth part of the whorl, just beyond the longitudinal 

lirations, of which approximately 30 occur on an average specimen. This species was described and illustrated in detail by Thein and Nitecki (1974, p. 38-42).

Euphemites incarinatus Easton, from the Pitkin 

Limestone of Arkansas, is a subglobose to globose species, narrower in the early stages, without umbilical 

depressions, and ornamented by more than 40 longitudinal lirae on the adult shell. The selenizone must be 

flush with the shell surface and not carinate, as this 

feature is so obscure that it never has been differentiated. On a broadly subglobose specimen in the USNM 

collection, 22 mm long, the lirae are very fine and faint 

and the overall shape is remarkably like that of 

Bellerophon, especially where the lirae are absent or 

obscured by wear.

Euphemites compressus Elias, from the Redoak Hollow Member of the Goddard Shale, Oklahoma, is inadequately known. Elias's species was illustrated only 

from the holotype, an incomplete juvenile shell, 4 mm 

long; in our opinion, it cannot be distinguished from the 

young stages of several other species. According to 

P. K. Sutherland (written commun., 1974) of the University of Oklahoma, this specimen is lost and no additional specimens are known. In 1954, Gordon and C. W. 

Tomlinson visited Elias's localities in the Redoak Hollow but found no additional gastropods. We are informed also by Sutherland (oral commun., 1973) that 

Elias and C. C. Branson searched for remnants of the 

limonitic sandstone that had provided Elias's original 

material, also without success. It seems, therefore, that 

no material is available to represent this species, and 

we recommend that the name E. compressus Elias be 

restricted to the holotype, if it still exists.

Of the nine named Mississippian species reviewed 

above, one (E. compressus) is unrecognizable, one (E. 

nautiloides) is probably synonymous with another (E. 

galericulatus), one (E. sedaliensis) is poorly understood, and a fourth (E. lentiformis) is not a typical Euphemites . Five species seem to be reasonably well established. We recognize five others from the Chainman 

Shale of Utah. Two of these are previously named western species, E. nevadensis Gordon and Yochelson and 

E. sacajawensis C. Branson, and another E. cracens, is 

described as new; two others are new, but the material 

is inadequate to be formally named. One specimen, 

from the Lunulazona sadlicki assemblage at Granite 

Mountain (USGS colln. 17092-PC) is unidentifiable 

but seems closest to E. sp. A. Three silicified specimens 

from the Wallet Gulch section (USGS colln. 17214-PC) 

were identified as Euphemites? sp. indet.

Euphemites cracens n. sp.

Plate 2, figures 9-11

Diagnosis. Somewhat compressed bellerophontaceans having well-rounded dorsum, ornamentation 

of fine, widely spaced lirae, and umbilical indentations.

Description. Early growth stages unknown. Shell 

smoothly curved in longitudinal profile, not geniculate. 

Dorsum rounded, following arc of small circle, flanks 

somewhat flattened so that profile in cross section is 

distinctly compressed; periphery more than threefourths of distance from dorsum to axis of coiling. Umbilical depression at either side of shell shallow and 

relatively narrow. Growth lines distinct, visible beneath covering inductura of mature part of shell; 

orthocline from umbilicus to beyond periphery, then 

curving smoothly prosocline and forming wide shallow 

U-shaped sinus over dorsum. Longitudinal ornamentation of fine lirae, relatively low and narrow, having 

interspaces three or four times width of each lira; 24 

lirae present on holotype, those nearest umbilici somewhat irregularly interrupted during development. 

Shell surface smooth near aperture, but selenizone 

present, bounded by very fine lira at either side, corresponding in width to slightly less than six middle lirae 

on dorsum. Slit depth and other apertural details unknown. At least one-fourth of mature body whorl 

covered by thin smooth inductura.

Dimensions. Holotype, partly crushed on one side 

near aperture, measures 10.4 mm in length and 8.2 mm 

(twice half width) in width.

Discussion. This species is known only from two 

specimens. The holotype is well preserved and comes 

from the northeastern end of the Foote Range, a few 

feet above a bed containing the ammonoid Richardsonites merriami (Youngquist). The paratype, poorly 

preserved, was found in a bed containing R. merriami 

in the Conger Range, 21.5 miles (34.4 km) due south of 

the first locality. Both specimens are associated with 

Euphemites sp. A. They are readily distinguished from 

that species by a more slender delicate shell, a more 

narrowly rounded dorsum, and umbilical depressions 

at maturity; narrow lirae and wide interspaces in E. 

cracens contrast with the fairly thick lirae and narrower interspaces of E. sp. A.
32 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

This species is not as compressed as E. galericulatus 

(Winchell), E. sedaliensis (Miller and Gurley), and E. 

subglobosus Hyde, all of which have length/width 

ratios of about 0.75 in comparison with 0.79 for E. cracens. E. galericulatus differs further in its galeiform 

shape and irregular oblique lirae on the lower flanks. 

Specimens of E. sedaliensis differ in having a more 

narrowly rounded dorsum and much broader umbilical 

depressions. E. subglobosus differs also in having more 

closely spaced lirae over the dorsum.

The only moderately narrow Pennsylvanian species, 

E. multiliratus Sturgeon, from the Vanport Limestone 

of Ohio, is somewhat less compressed than the Chainman form but is otherwise similar in shape. It has more 

numerous lirae than E. cracens.

Types. Holotype USNM 210923; paratype USNM 

210924.

Occurrence and number of specimens. USGS collections 22880-PC (1), 22883-PC (1), Millard County.

Euphemites nevadensis Gordon and Yochelson

Plate 2, figures 5, 6

Euphemites nevadensis Gordon and Yochelson, 1983,

p. 973-974, figs. 1A-G.

Discussion. This species was described from the Diamond Peak Formation in east-central Nevada. Additional specimens have been identified in the collections 

from the Chainman Shale, and one is figured from the 

Jensen Wash section, Burbank Hills.

Euphemites nevadensis probably belongs to the same 

species group as E. vittatus (McChesney) and E. 

blaneyanus (McChesney). It is well rounded across the 

dorsum, and it is not geniculate. This species differs 

from those two common Pennsylvanian species in lacking any indication of lateral nodes in the columellar 

area. Presumably the difference between a smooth inductural layer and one bearing nodes is related to a 

different configuration of the area of the mantle that 

deposited this layer.

Figured specimen . USNM 211078.

Occurrence and number of specimens. USGS collections 17056-PC (1), 17188-PC (1), 17209-PC (1), 

17219-PC (1), 25547-PC (1), 25550-PC (2), 725566- 

PC (4), Millard County.

Euphemites sacajawensis C. C. Branson

Plate 2, figures 14, 15

Euphemites sacajawensis C. C. Branson, 1937, p. 658, 

659, pi. 89, fig. 25 [not figs. 24, 33]; Gordon and 

Yochelson, 1975, p. F10, Fll, pi. 1, figs. 7-9 [not 

figs. 6, 11-13]. 

Discussion. The primary types of this species from

the Amsden Formation of Wyoming were redescribed

and refigured by Gordon and Yochelson (1975, p. F10, 

pi. 1, figs. 6-9, 11-13), who suggested that two different forms might be represented. The holotype would 

constitute one form and the figured paratypes, the 

other. At that time, the unfigured paratypes were not 

available, but we have since had the opportunity to 

study them. The holotype is a distinct specimen. However, we believe that all but one of the paratypes represent a second species of Euphemites. The remaining 

paratype is a steinkern, probably of the gastropod we 

described in the Amsden report as Knightites 

(Retispira) sp. A. We recommend, therefore, that the 

characters of E. sacajawensis be restricted in concept to 

the holotype; our description of that species in the Amsden report was based solely upon that specimen, a 

small globose Euphemites having deep infundibuliform 

umbilical depressions and ornamented by 22 strong 

rounded spiral lirae having interspaces about twice as 

wide as the lirae. Although the paratypes are well 

enough preserved to define another species, it is not 

appropriate to do so here.

The globose shells from the Heath Formation of Montana described by Easton (1962, p. 98, pi. 13, figs. 9,10) 

as E. sacajawensis C. Branson lack the infundibuliform 

umbilical depressions and have 22 to 28 elevated, flatsided spiral lirae. They probably represent still another 

species, closely related to if not identical with 

Euphemites sp. A in the Chainman Shale.

Specimens from the Burbank Hills, Utah, occur in 

the Glabrocingulum (Ananias) seminudum assemblage, the stratigraphically highest gastropod faunule 

in the Chainman Shale. The shells have prominent 

infundibuliform umbilici and 22 or rarely 23 longitudinal lirae. As these are the principal characters upon 

which the identification of E. sacajawnesis rests, we are 

reasonably certain in referring these Utah shells to 

Branson's species. The umbilici, however, seem a little 

wider than in the holotype of E. sacajawensis . One 

other specimen, in the Glabrocingulum quadrigatum 

assemblage in the section at Granite Mountain is also 

referred to this species.

Figured specimen . USNM 210932.

Occurrence and number of specimens. USGS collections 25249-PC (1), Juab County; 17059-PC (2), 

17217-PC (4), 25548-PC (1), Millard County.

Euphemites sp. A 

Plate 2, figures 1-4

Discussion. Specimens of a well-rounded 

Euphemites occur in the upper part of the Chainman 

Shale in the general area and can be described as follows: Globose bellerophontaceans ornamented by numerous closely spaced longitudinal lirae. Shell
SYSTEMATIC PALEONTOLOGY 33

smoothly curved, without geniculation. Earliest 

growth stages unknown. Whorls anomphalous, having 

shallow umbilical indentations in immature stage 

which are lacking at maturity; shell becoming inflated 

with growth so that mature profile in cross section is 

approximately semicircular from columellar areas 

across dorsum. Ornamentation of 22 to 28 prominent 

coarse lirae, more or less uniformly spaced across dorsum but a little closer near umbilical region, having 

interspaces approximately twice as wide as individual 

lirae. Lirae distinctly elevated, having straight nearly 

vertical sides and rounded on top; each lira continuous 

for at least one whorl, new lirae added rarely in columellar areas and even less commonly on dorsum. Mature part of aperture covered by smooth inductura.

This material, despite including shells as long as 

18 mm, contains no complete specimens, so the details 

of the smooth area near the aperture, the selenizone, 

and the lip are not available. Most of the specimens are 

otherwise well preserved.

In its globose shape and the coarseness of its lirae, 

this species shows some similarity to Euphemites sacajawensis C. C. Branson, which was based upon a specimen from the Amsden Formation of Wyoming. It differs from E. sacajawensis, however, in lacking 

infundibuliform umbilical depressions and in the shape 

of its spiral lirae, which are straight-sided and lathlike, 

rather than low and rounded. These lirae of E. sp. A 

resemble those seen on the specimens from the Heath 

Formation of Montana, specimens that Easton (1962, 

p. 98) referred to E. sacajawensis but that we do not 

include in that species. Study of larger suites of specimens from both Montana and Utah is necessary to 

show whether or not they are conspecific.

Figured specimens. USNM 210925, 210926.

Occurrence and number of specimens. USGS collections 17189-PC (1), 22880-PC (7), 22883-PC (2), 

25551-PC (1), Millard County.

Euphemites sp. B

Plate 1, figures 27, 28

Discussion. A single steinkern, having patches of 

shell adhering at the umbilical region on both sides and 

to a partial external mold, differs in several characters 

from the common Euphemites sp. A. This specimen is 

10.3 mm long and 9.7 mm wide. It was collected from 

the uppermost fossiliferous bed of the Goniatites americanus Zone in the Granite Mountain section and is 

presumably late Meramecian in age. Although comparisons of shape are difficult because all our specimens of Euphemites sp. A retain their shell, this form 

seems slightly less globose than that species. The sculpture differs in that the longitudinal lirae are narrower

and the interspaces wider than in E. sp. A, and the lirae 

around the umbilicus are broken into a succession of 

short dashlike segments, rather than being only locally 

interrupted as in E. sp. A.

The specimen is particularly interesting because the 

inner part of the slit is preserved on the steinkern. This 

is approximately parallel sided, 2 mm wide, and has a 

U-shaped rather than V-shaped termination; what remains of the slit is 4.5 mm long. The outer lip is broken 

back, so an exact measurement cannot be taken, but 

part of the curved lip near the umbilicus is preserved. 

Although the slit depth is thus less than the maximum 

during life, probably little shell was lost by this breakage. The slit depth was somewhat less than one-fourth 

whorl, but certainly deeper than in E. sp. A.

Figured specimen. USNM 210927.

Occurrence. USGS collection 17018-PC, Juab 

County.

Family BELLEROPHONTIDAE

Subfamily BELLEROPHONTINAE

Genus BELLEROPHON Montfort, 1808

Subgenus B. (BELLEROPHON) Montfort, 1808

Discussion. In contrast to genera such as Euphemites or Knightites, Bellerophon (Bellerophon ) has 

a shell that lacks prominent ornamentation. The other 

two currently recognized subgenera of Bellerophon, B. 

(Aglaoglypta) and B. (Pharkidonotus), bear quincuncial ornament or nodelike irregularities, respectively. 

The typical shell of Bellerophon (Bellerophon) has a 

surface that ranges from polished to slightly roughened 

by irregularly spaced growth lines; no strong collabral 

ornament is developed. A few species have been described as Bellerophon in which sublamellose transverse ornamentation is rather prominent, and these 

species are tentatively included in the typical subgenus. Several other species included in this genus 

combine prominent transverse costae and a wide deep 

umbilicus; we believe that these should be reassigned 

but consider the problem as outside the scope of this 

paper. So far as we can determine, Bellerophon mansfieldianus Girty, from the Madison Limestone of Idaho, 

is the only described American species that belongs in 

this category.

Because the ornamentation of the shell in this subgenus is relatively simple, considerably more emphasis 

than usual must be placed on shell shape. Shells of 

typical Bellerophon (Bellerophon) range in cross section from subhemispherical to bell- or helmet-shaped. 

Some important differences occur in the umbilical region and adjacent parts of the aperture. The type species of Bellerophon (B. vasulites Montfort) is minutely 

phaneromphalous. Most species included in the sub-
34 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

genus, however, are anomphalous, some having shallow umbilical depressions and others lacking depressions.

Some differences also may be observed in the posterior part of the aperture, particularly where the inner 

lip joins the main body of the shell. In some species, the 

inner lip is produced posteriorly at either side as a 

flaring shelf, particularly in specimens that are 

phaneromphalous or possess prominent umbilical depressions. Other species have the inner lip massive and 

subcylindrical, joining the shell at a fairly narrow angle without flaring; this feature is particularly characteristic of species in which umbilical depressions are 

small or lacking. If the inner part of the lip adjacent to 

the columellar region is essentially straight, the approximate angle that it makes relative to the axis of 

coiling may vary between species. In many species, this 

part of the lip is not straight but is sinuate and reflexed 

backward to form a shallow excavation adjacent to the 

columellar region. Although details of this area have 

been neglected in most descriptions of Mississippian 

and Pennslyvanian forms, they have been used to differentiate North American Permian species.

Another important feature for distinguishing species 

of Bellerophon is the selenizone and its various characteristics. We would place weight on whether the selenizone is essentially flush with the dorsal shell surface or 

raised in some way. The selenizone of several species is 

raised and flat topped. In some species, the selenizone 

is delineated at either side by shallow sulci. In still 

other species, the selenizone is bordered by a prominent 

raised cord at either side. Lunulae are generally rare 

on the Bellerophon selenizone.

As in most emarginate gastropods, the relative depth 

of the slit remains an untested specific character. Our 

impression is that the selenizone in most Bellerophon 

species is relatively narrower than that of other late 

Paleozoic bellerophontaceans. A few species do have a 

relatively wide selenizone; this may be a significant 

species character.

The inductura is of little significance as a species 

characteristic in Bellerophon (Bellerophon}. It commonly is present as a thin unornamented sheet, which 

extends only a short distance outside the aperture. 

Prominent development of a boss is rare in this subgenus.

Finally, we return to the subject of surface ornamentation, which at the outset we said is not a major character in differentiating species of Bellerophon. It nevertheless has some utility. Some Bellerophon shells are 

smooth and have very fine growth lines or striae. Other 

species have what might be described as microlamellae, which are slightly raised on the adapertural side. 

Still others are sublamellose, and some are fully lamellose. All these characters in combination with one another are useful for distinguishing between the various 

species of Bellerophon (Bellerophon}.

American Mississippian species of Bellerophon

(Bellerophon). 

chesterensis S. Weller, 1920 

claxtonensis Thein and Nitecki, 1974 

gibsoni White, 1882 

majusculus Walcott, 1884 

?mansfieldianus Girty, 1927 

menardensis Thein and Nitecki, 1974 

needlensis n. sp. 

panneus White, 1862 

pitkinensis Snider, 1915 

scissilis Conrad, 1844 (as B. scissile} 

spergenensis Gordon and Yochelson, 1983

[n. nom. for B. sublaevis Hall, 1856, not Potiez

and Michaud, 1838]

vespertinus Gordon and Yochelson, 1983 

welshi n. sp.

Although 35 bellerophontaceans in the United 

States were described as Bellerophon from Mississippian rocks (Yochelson and Saunders, 1967, p. 37-39), 

probably no more than 11 valid species of B. 

(Bellerophon} are represented in the Mississippian as 

presently defined. To these we add in this report two 

more named species. Other bellerophontaceans originally described as Bellerophon are transferred to different genera in this report and are discussed under those 

genera.

Although we agree that Bellerophon bilabiatus 

White and Whitfield and B. vinculatus White and 

Whitfield, from the English River Formation of Iowa, 

B. Helena Hall, from the Bedford Shale of Ohio, and B. 

jeffersonensis Weller and B. ulrichi Weller, from the 

 Glen Park Limestone of Missouri, should be included in 

Bellerophon (Bellerophon}, they all come from rocks 

formerly included in the Kinderhookian but now regarded as Late Devonian in age.

The remaining Bellerophon species from rocks still 

considered to be Early Mississippian in age are poorly 

established. Moreover, no anomphalous Bellerophon 

has been described in the Early Mississippian of North 

America. B. (B.} panneus White occurs in the upper 

Devonian English River Formation at Burlington, 

Iowa, but the imperfect and distorted types come from 

a somewhat higher horizon, according to Weller (1900, 

p. 114). Weller (1901, p. 203, pi. 20, figs. 14, 18) illustrated one of White's types and suggested that the specimen illustrated by Keyes (1894 [1895], pi. 50, fig. 3) as 

B. bilabiatus was a good example of B. panneus. The 

shell of this species is medium sized, a little wider than 

long, broadly umbilicate, having a narrow selenizone
SYSTEMATIC PALEONTOLOGY 35

that is subcarinate toward the aperture and a broad 

notch on the outer lip.

Bellerophon blairi Miller and Gurley, from the 

Chouteau Limestone of Missouri, as redescribed and 

figured by Branson (1938, p. 103, pi. 14, figs. 2-4), has 

a compressed shell with a flaring aperture. It does not 

belong in the genus Bellerophon, but, from the information available, we are unable to assign it to any of 

the explanate bellerophontacean genera. Bellerophon 

scotti Branson, from the Northview Shale of Missouri, 

was described from steinkern and cannot be compared. 

One cannot even be certain that this is a Bellerophon.

Bellerophon whittleseyi Winchell, from the "Marshall 

Sandstone" of Cuyahoga County, Ohio, was based upon 

a unique specimen figured by Whittlesey (1851, p. 219, 

figs. 1, 2) as a goniatite. The illustrations and 

Winchell's subsequent description show some significant discrepancies, which we are unable to resolve. Relying on the illustrations alone, we would conclude that 

the specimen is a platyceratid rather than a 

bellerophontacean; we cannot, however, exclude its being a Sinuitina, as is suggested by Winchell's statement that it resembles B. rugosiusculus Winchell. We 

are transferring this species arbitrarily to Platyceras, 

and we recommend that this specific name not be used 

again until such time as Whittlesey's specimen is reexamined.

Owen (1852, p. 627) listed as Bellerophon hiulcus 

Sowerby? (originally one of Martin's species), a poorly 

preserved steinkern from the Keokuk rapids of the Mississippi River. This record was cited as "Bellerophon 

hiuleus Owen" by Weller (1898, p. 139) in his bibliographic index of North American Carboniferous invertebrates. Owen's specimen was unidentifiable and certainly provided no basis for recognizing this northwest 

European bellerophontacean in the American Midcontinent.

Four species of Bellerophon (Bellerophon} were described from rocks of Meramecian (early Late Mississippian) age in the United States. The most common of 

these is B. (B.) spergenensis Gordon and Yochelson 

[=B. (B.) sublaevis Hall, 1856, notfi. sublaevis Potiez 

and Michaud, 1838] from the Salem Limestone of Indiana. This is a moderate-sized smooth subglobose species having the last whorl somewhat inflated, the inner 

lip of the aperture meeting the umbilical areas at a 

very low angle to the axis of coiling, a narrow flat to 

slightly raised selenizone, and a relatively shallow slit.

The rest of the Meramecian bellerophons are generally large species. B. (B. ) scissilis Conrad was described 

from Ste. Genevieve, Mo. Although Conrad did not figure this species or identify the formation and precise 

locality from which he obtained his type, his description fits a large species of B. (Bellerophon) that occurs

in a shale bed approximately in the middle of the Ste. 

Genevieve Limestone in quarries in the northern environs of Ste. Genevieve, Mo. Silicified red-weathering 

shells of this handsome species in USNM and USGS 

collections reach a maximum length of slightly more 

than 85 mm. Many have parts of the raised selenizone 

weathered away, accounting for the "profound channel" mentioned in Conrad's description; actually the 

slit is relatively short. The shell is subglobose, the 

aperture is flared adjacent to the umbilical areas, and 

the surface is distinctly lamellose.

B. (B.) gibsoni White is a slightly smaller species, 

inadequately based upon a steinkern, from the St. 

Louis Limestone in the vicinity of Greencastle, Ind. 

Knight (1947, pi. 42, figs. 3a-c) figured another 

steinkern, from Greencastle Junction, that seems to be 

the same as White's form. Until its external characters 

are determined, one cannot separate this species readily from B. (B.) scissilis. Undescribed silicified specimens from St. Louis Limestone at other localities in the 

northern Midcontinent are present in the USNM collection; these certainly differ from Bellerophon scissilis, but it is not clear whether or not they are conspecific with B. (B.) gibsoni.

The largest North American Mississippian species is 

B. (B.) majusculus Waleott, from the Diamond Peak 

Formation in the Eureka District, Nev., the holotype of 

which is 105 mm long. This narrowly subglobose shell 

has well-rounded dorsolateral slopes and a prominent 

raised carina set off by shallow sulci.

Four species were described from rocks of Chesterian 

age in the United States. B.(B.} chesterensis S. Weller, 

from the basal part of the Okaw Limestone of Illinois, 

is a small rotund anomphalous species having a low 

crest and a thickened inner lip that joins the columellar 

area at an angle of roughly 60° to the axis of coiling; its 

narrow convex selenizone becomes somewhat elevated 

during growth. B. (B.) claxtonensis Thein and Nitecki 

from the Golconda Formation and Menard Limestone 

of Illinois has an anomphalous shell, highly arched dorsally, slightly longer than wide, and having a narrow, 

slightly raised selenizone terminating in a short slit, 

the smooth surface of the shell ornamented only by 

indistinct growth lines. B. (B. ) menardensis Thein and 

Nitecki from the Menard Limestone, intermediate in 

general shape between B. (B.) chesterensis and B. (B.) 

claxtonensis, has an evenly round whorl profile tending 

to flatten somewhat toward the aperture. The narrow 

selenizone is flush with the whorl surface except near 

the aperture, where it is slightly elevated and bordered 

by shallow grooves. The umbilical depressions are 

closed by thickened shell and a parietal inductura 

covers about one-fifth of the last whorl. B. (B.) pitkinensis Snider, from the Pitkin Limestone in Oklahoma,
36 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

was poorly illustrated, and its description is lacking in 

various details. It has a subglobose shell bearing a 

prominent dorsal carina that widens anteriorly and is 

set off by shallow sulci.

Diagenesis in the Willow Gap Member of Sadlick 

(1966) in the Confusion Range has strongly affected 

some of the Chainman bellerophons. Many are coarsely 

silicified and some have the external shell layer 

leached. For this reason, most of the specimens could 

only be identified as Bellerophon (Bellerophon) sp. 

indet., as in USGS collections (number of specimens in 

parentheses) 14558-PC (1), 15355-PC (1), 15361-PC 

(2), 15362-PC (3), 15363-PC (1), 17023-PC (1), 25563- 

PC (4), or B. (Bellerophon)? sp. indet. as in USGS collection 25271-PC (1).

Bellerophon (Bellerophon) vespertinus Gordon and Yochelson

Plate 1, figures 24-26

Bellerophon (Bellerophon) vespertinus Gordon and

Yochelson, 1983, p. 975-976, figs. 1 H-N.

Discussion. This species was described from eastcentral Nevada. Specimens are common, though scattered through many localities, in the upper part of the 

Chainman Shale; indeed, this is the most abundant of 

the bellerophontacean species, and a few good specimens have been obtained. However, the bellerophontaceans do not begin to approach the abundance of 

Glabrocingulum in the gastropod fauna.

The raised selenizone distinguishes B. (Bellerophon) 

vespertinus from B. (B.) welshi, and the subquadrate 

shape further contrasts with the rounded profile of that 

species. This subquadrate shape also distinguishes this 

species from B. (B.) needlensis, which has a narrower 

dorsum. However, these details of shape are subject to 

the vagaries of preservation. For a time, some of the 

Utah specimens were thought to constitute a distinct 

species, being laterally compressed and bearing a channeled selenizone. Other Utah specimens do show areas 

where the selenizone is raised; still other associated 

specimens are not compressed (pi. 1, figs. 24-26). This 

is an excellent example of the advantage of having a 

large sample for study.

Figured specimen. USNM 210934.

Occurrence and number of specimens. USGS collections 17087-PC (2), Juab County; 715358-PC (1), 

716997-PC (1), 717059 (1), 17217-PC (3), 722880-PC 

(1), 25551-PC (18) Millard County.

Bellerophon (Bellerophon) welshi n. sp.

Plate 1, figures 12-14

Diagnosis. Medium-sized globose Bellerophon, 

having semi-oval transverse whorl profile; surface

smooth but microscopically sublamellose; selenizone 

narrow, flush.

Description. Shell broadly rotund; transverse 

whorl section gently convex over dorsum, more 

strongly rounded dorsolaterally, and sloping steeply 

and nearly straight on flanks, forming smooth curve 

between columellar areas. Selenizone narrow, flattopped, generally flush with surface but raised slightly 

locally, particularly in more juvenile part. Aperture 

reinform in section; shell anomphalous; lip thick adjacent to columellar areas, projecting outward and forward at angle of about 45° to axis of coiling. Inner side 

of aperture covered by thin inductura, extending considerably farther up lateral slopes than on dorsum. 

Outer lip unknown. Surface smooth, verging on polished. Growth lines faint and closely spaced, but appearing microscopically sublamellose, bowing gently 

toward aperture, but essentially orthocline from columellar areas to about half distance to selenizone, then 

curving gently prosocline for remainder of distance, 

becoming a little more strongly arched adjacent to 

selenizone. Lunulae within selenizone evenly curved 

and of same strength as growth lines. Slit not known 

but probably relatively shallow and probably less than 

one-quarter whorl in depth.

Dimensions. Holotype, lacking final one-quarter 

volution of shell, measures 20.7 mm in length and 

23.5 mm in width.

Discussion. The holotype is a well-preserved but incomplete specimen collected in the Burbank Hills; several poorly preserved specimens are also referred to 

this species. Traces of coloration may be present in the 

holotype, as the main part of the shell is dark-grayishbrown and the inductura is chocolate brown.

In the development of an apertural inductura and in 

having a flush selenizone, this species is similar to B. 

(Bellerophon) spergenensis Gordon and Yochelson. 

However, that form is narrower and more highly 

arched over the dorsum. The Chainman shell is also 

somewhat like B. (B.) chesterensis Weller, except that 

the Illinois species is more semicircular in profile, has 

a narrow raised rounded selenizone throughout 

growth, and an inner lip with an even greater angle 

(60°) to the axis of coiling. Perhaps the species most like 

B. (B.) welshi is B. (B.) menardensis Thein and Nitecki. 

Both species have a broad rounded whorl profile and 

generally flush selenizone. B. (B.) menardensis differs 

in having a less smooth outer shell surface and in the 

narrower angle the inner lip makes with the axis of 

coiling of the shell.

B. (B.) welshi is distinguished from all the other 

Chainman species by having a broad curvature of the 

transverse whorl profile and the flush selenizone. It is 

named for J. E. Welsh, who collected the holotype.
SYSTEMATIC PALEONTOLOGY 37

Types. Holotype USNM 210928; paratypes 210929, 

210933.

Occurrence and number of specimens. USGS collections 17310-PC (2), 25274-PC (1), Millard County.

Bellerophon (Bellerophon) needlensis n. sp.

Plate 1, figures 18-20

Diagnosis. Medium-sized globose Bellerophon having strongly oblique inner lip and narrowly arched 

whorl profile; surface smooth except for closely spaced 

growth lines; selenizone narrow, convex.

Description. Shell slightly longer than wide, rather 

highly arched; transverse whorl profile somewhat bell 

shaped, having rather narrow rounded dorsum curving 

to sloping, nearly flat sides that flare very slightly near 

aperture. Arcuate dorsal profile interrupted medially 

by slightly raised narrow convex selenizone; lunulae 

well formed, rather irregularly spaced. Shell anomphalous; shallow cavity present at either side behind 

inner margin of lip, but no true umbilical depression. 

Inner part of lip thick, joining main part of shell approximately at 45° to axis of coiling. Growth lines forming shallow adaperturally convex curve for approximately three-fourths distance across shell, curving 

gently prosocline on dorsum, but more steeply near 

selenizone so as to meet it at low angle; growth lines 

very fine and closely spaced, but some coarser ones 

irregularly interspersed; none appear lamellose, even 

microscopically. Aperture imperfectly known, but judging from growth lines, marked by a medial narrow subtriangular notch; depth of slit unknown but presumably relatively short.

Dimensions. Holotype is 33.5 mm long, 30.0 mm 

wide, and 25.5 mm high at right angles to length.

Discussion. This species is based upon two specimens from the northern part of the Needle Range. They 

occur in the upper part of the Chainman Shale, 10 to 

12 feet (3.0-3.7 m) below a bed containing the ammonoid Richardsonites merriami Youngquist. Two 

more specimens, one fairly complete, from the upper 

part of the Willow Gap Member of Sadlick (1966) in the 

Skunk Spring section also belong in this species.

B.(B.) needlensis is differentiated fromB. (B. ) welshi 

n. sp. by its more highly and narrowly arched oval 

whorl profile and its distinctly raised selenizone. Two 

other Chainman species, B. (B.) vespertinus Gordon 

and Yochelson and B. (Bellerophon?) sp. also have 

raised selenizones, but the oval profile of B. (B.) 

needlensis distinguishes it from the more trapezoidal 

whorl profile of both these taxa. B. (B.) chesterensis, 

from the Okaw Limestone of Illinois, is about half the 

size ofB. (B.) needlensis', it has a slightly lower selenizone and is intermediate in shape between B. (B.) 

needlensis and the two species mentioned above.

Types. Holotype USNM 210930; paratype 210931.

Occurrence and number of specimens. USGS collections 15160-PC (2), 725272-PC (2), Millard County.

Bellerophon (Bellerophon?) sp. A

Plate 1, figures 15-17, 21-23

Discussion. Another Bellerophon is known from a 

few fragments and from a single immature specimen, 

5.8 mm long and 5.5 mm wide, collected from shale 

overlying the Richardsonites merriami bed in the Foote 

Range measured section. This species has a subtrapezoidal whorl profile, thick shell, rugose outer surface, 

and a prominent raised and rounded median crest occupied by the selenizone. The crest is wider, more elevated, and therefore more prominent than the one in B. 

(B.) vespertinus n. sp., and the flanks are more flattened. The aperture is slightly inflected at the umbilical areas and shows a tripartite shouldered profile on 

the outer side. The shell surface is uneven, forming 

irregularly spaced collabral ridges or small varices at 

points of interruption of growth. Also present are numerous tiny collabral lamellae.

The shapes suggest that these specimens could be 

immature individuals of B. (B.) majusculus Walcott, 

described from the lower Carboniferous of the Eureka 

district, Nevada, but the holotype of that species is 20 

times larger than our most complete specimen, and its 

whorl profile is a little more rounded. A comparison of 

these dissimilar ontogenetic stages in the absence of 

well-preserved intermediate growth stages is not warranted.

The shouldered profile of the Utah shell also resembles that of the subgenus B. (Pharkidonotus) Girty, but 

that group is only known in rocks of Pennsylvanian 

and Permian age. As the shape of mature specimens of 

this species is not known, we cannot place it with certainty in either subgenus of Bellerophon.

Figured specimens. USNM. 210935, 211085, 

211086.

Occurrence and number of specimens. USGS collections 22883-PC (2), 25275-PC (5 fragments), Millard 

County.

Subfamily KNIGHTITINAE 

Genus RETISPIRA Knight, 1945

Discussion. Retispira has been used both as a subgenus and a genus. We follow Batten (1972, p. 13) in 

treating it as a full genus. It is by all standards the 

most complex genus within the subfamily Knightitinae. Our study of the Chainman Shale gastropod fauna
LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

led us to examine many Mississippian and Pennsylvanian species ofRetispira. These species have many features in common, and we do not feel prepared to recognize any separate phylogenetic stocks. However, as a 

consequence of our close examination of the wellpreserved Chainman specimens, we did observe features that clarified our general understanding of the 

group.

The relative importance of various morphologic features in differentiating species cannot be ranked with 

certainty, but general shape obviously must be of prime 

significance. Specimens of Retispira range from relatively narrow compressed forms to those that expand at 

a fairly rapid rate and approach a lenticular shape. 

This rate or degree of lateral expansion is not exploited 

widely as a specific character, and its delineation is 

still highly qualitative. Associated with general expansion is presence or absence of geniculation, which may 

result either from flattening to form an explanate aperture or from the development of a prominent boss. None 

of the Chainman specimens that we describe develops 

a prominent inductural boss within the aperture, but at 

least one has this incipient feature some distance back 

within the aperture. We suspect that development of a 

boss may be a feature of maturity and also that it may 

be more common in the broader species.

All the species that we examined show an ontogenetic change in the whorl profile. In general, shells are 

narrowly rounded dorsally in the juvenile state, become more inflated as maturity approaches, and eventually may have a rather flat dorsum. Ontogenetic 

change seems to have been generally neglected in descriptions of bellerophontaceans, and we emphasize it 

here. Any meaningful comparison of species should be 

made with specimens of the same approximate size.

The umbilical region of Retispira ranges from 

phaneromphalous to anomphalous. Most species have a 

narrow to minutely phaneromphalous umbilicus. This 

latter condition is difficult to differentiate from an umbilical depression in which none of the inner whorls are 

visible. The expansion of the inner part of the lip commonly marks the umbilical region, and, when broken 

specimens are examined, this area of the shell is difficult to interpret. Although a moderately wide umbilicus may be an important differentiating character, we 

are less certain of the significance of a narrow umbilical chink versus a false umbilicus.

The shape and ornamentation of the selenizone have 

been neglected as significant characters. The Chainman Shale species include those that have a flattened 

flush selenizone and those that have the selenizone 

arched. This obvious character is reinforced further by 

more subtle differences in the size and spacing of the 

lunulae and the degree to which spiral lirae occur on

the selenizone. In general, all specimens ofRetispira in 

which the slit is known have an emargination that is 

quite short and generally less than one-sixth of a whorl 

in depth. Although we have not investigated this matter in detail, we suspect that some importance may be 

attached to the relative width of the selenizone as well 

as to its profile.

The reticulate ornamentation is probably the most 

obvious feature of this genus. The ornament is best 

considered by studying its two components independently. In this group, the term "collabral ornamentation" is particularly appropriate, for only the occasional growth line reaches the size of a lira. We observe 

consistent differences in the size of such lirae among 

species and also note differences in the number of 

threads interspersed between lirae. The precise spacing of collabral lirae changes with the ontogenetic 

stage. The lirae generally become more widely spaced 

as the animal matures but subsequently tend to decrease in spacing in even older specimens. Commonly, 

the distribution of the lirae shows some individual 

variation, so we would place greater emphasis on the 

general texture of the sculpture rather than on a count 

of the number of collabral lirae in a given length of 

shell.

On close inspection, the collabral ornamentation 

varies in shape as well as in size. Each individual lira 

is typically asymmetrical, having its steeper side toward the aperture. None of the species ofRetispira from 

the Chainman Shale seems to be lamellose or even 

sublamellose, but, where seen under magnification, 

species differ in the degree of prominence of the growth 

lines, some tending toward sublamellose. Whether the 

collabral ornamentation is subdued or prominent is, of 

course, partly related to the weight of the lirae. However, as a result of the asymmetry of the sculptural 

elements, the finer lirae on some forms may appear 

more prominent than the actually coarser lirae on 

other forms.

Spiral lirae are of several sizes. We have found it 

useful to recognize coarse, regular, and fine lirae, and 

three similar divisions among threads; distinctions 

among these sizes are arbitrary but do provide a meaningful basis for making comparisons among species. 

Grouping the lirae by size provides more data than 

simply counting the number of lirae. Ontogenetic 

change in the ornamentation is common. During 

growth, most species add spiral lirae and increase the 

size of those elements present earlier, though the ornament does not necessarily coarsen continuously as the 

age of the animal increases.

The intersection of collabral and spiral ornamentation forms the reticulate pattern. This pattern may be 

nearly square, transversely rectangular, or elongate
SYSTEMATIC PALEONTOLOGY 39

parallel to the spirals. Characteristically, this pattern 

changes with ontogeny, and undoubtedly this change is 

one of the principal features in making the group so 

confusing at first glance. The intersection of the two 

directions of lirae is commonly simple, and only rarely 

do species develop interference nodes or pustules. However, a change may take place laterally in some species 

so that the dorsum and upper flanks are reticulate but 

the intersections near the umbilical areas are pustulose. Analysis of the reticulate pattern into its components is certainly an important tool for differentiating 

species.

North American Mississippian species o/"Retispira. 

albapinensis Gordon and Yochelson, 1983 

barquensis (Winchell), 1862 (Bellerophon) 

beedia (Bell), 1927 (Bucanopsis) 

cincta n. sp. 

eliasi n. nom for Bucanopsis (Retispira?) reticulata

Elias, 1958 [not Bellerophon reticulatus McCoy,

1844]

jensenensis n. sp.

lineolata (Hall), 1859 (Bellerophon} 

michiganensis (Winchell), 1862 (Bellerophon) 

minima (Bell), 1911 (Bucanopsis perelegans, var.) 

missouriensis (Swallow), 1863 (Bellerophon) 

monroensis (S. Weller), 1916 (Bellerophon) 

nolani Gordon and Yochelson, 1983 

ordinata n. sp.

ornata (S. Weller), 1920 (Bucanopsis) 

perelegans (White and Whitfield), 1862

(Bellerophon) 

stenopsis n. sp.

textilis (Hall in Miller), 1877 (Bellerophon) 

waverliensis (Hyde), 1953 (Bucanopsis)

Fourteen species of bellerophontaceans that belong 

in Retispira have been described previously from the 

Mississippian rocks of North America; eight were assigned by Thein and Nitecki (1974, p. 51) to Retispira, 

of which we retain six, proposing a new name for one of 

them. We also are describing four new species from 

Utah. We include in Retispira all but one of the species 

listed by Yochelson and Saunders (1967, p. 54) under 

Bucanopsis, which is an early Paleozoic genus not 

found in upper Paleozoic rocks. Bucanopsis deflectus S. 

Weller, from the English River Formation of Iowa, is 

not included here because it occurs in beds now considered to be Late Devonian in age. We also refer to 

Retispira several of those species listed by Yochelson 

and Saunders (1967, p. 39-44) under Bellerophon 

(Bellerophon).

Three species of Kinderhookian age belong in this 

subgenus. Bellerophon lineolatus Hall, from the Rockford Limestone of Indiana, has never been figured. The

whereabouts of the type specimen or specimens is not 

known; the species is not listed in the catalogue of types 

in the American Museum of Natural History (Whitfield and Hovey, 1898-1901), where many of Hall's 

types reside. Hall's description is sufficient for recognition of the species as a Retispira, but not detailed 

enough to permit distinguishing it from other species 

in the subgenus. We hereby restrict the name to the 

type lot and suggest that it not be used further until the 

type lot, if it still exists, has been redescribed and figured.

Bucanopsis perelegans White and Whitfield, from the 

Prospect Hill Sandstone Member of the Hannibal Formation of Iowa, has a subglobose shell, which bears a 

slightly raised flat selenizone bordered by a narrow 

groove at either side. The sculpture consists of fine, 

closely spaced spiral lirae crossed by slightly finer collabral threads that give the surface a minutely cancellated appearance, at least on external molds. Weller 

(1901, p. 178,179, pi. 15, figs. 23,24) figured the largest 

of the syntypes. We have examined several topotypes in 

the USGS collections.

Bucanopsis waverliensis Hyde, from the Byer Member of the Logan Formation of Ohio, is known only from 

incomplete specimens. Its shape and cancellate ornamentation is in accordance with Retispira, to which it 

is here transferred. This subglobose species has a 

slightly raised, narrow selenizone, at either side of 

which are 12 primary spiral lirae, between each pair of 

which are three to five additional spiral threads near 

the aperture and one to three farther back. Collabral 

lirae form a cancellate pattern of squares and transverse rectangles with the primary spiral lirae.

Two Osagean species were described from the Marshall Formation of Michigan (Winchell, 1862). These 

are Bellerophon michiganensis Winchell and B. barquensis Winchell, which we hereby transfer to 

Retispira. Winchell's types were borrowed by G. H. 

Girty for study some years ago, and we have been fortunate in having access to Girty's unpublished notes and 

figures. Girty's figures of R. michiganensis and topotypes from Battle Creek, Mich., in the USNM collection 

show this to be a globose species, generally somewhat 

wider than long. The narrow selenizone is gently convex but subdued. A delicate pattern of alternating spiral lirae and threads of at least three orders is crossed 

by finer collabral lirae. The slit seems to be shallow.

R. barquensis is not established so clearly. Winchell 

(1862, p. 427) stated that it differed from R. michiganensis in having a constricted aperture and a single 

set of lirae. Girty's notes show that he suspected that/?. 

barquensis might be a synonym of R. michiganensis, 

the constriction of the aperture being an individual 

variation on the type, and the lack of finer threads a
40 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

condition of preservation. However, he believed that 

the material was insufficient for a final decision.

Two species are known from Meramecian rocks in 

the United States. The earlier is R. textilis (Hall), from 

the Salem Limestone of Indiana. Hall's species should 

not be confused withBucania textilis Koninck, from the 

Visean of Belgium, which likewise belongs in Retispira 

and is, therefore, a secondary homonym, as Hall's textilis was proposed in 1877 (in Miller, 1877, p. 254-256) 

and Koninck's in 1883. The Indiana shell is subglobose 

and has a generally flush or only slightly raised selenizone, without flanking grooves. The spiral ornamentation includes lirae and threads of three ranks, but the 

overall aspect of the collabral lirae is that of fairly 

coarse cancellation. The intersections of the spiral and 

collabral lirae tend to form tiny nodes.

Bellerophon monroensis S. Weller (1916), from the 

Ste. Genevieve Limestone in Illinois, is a fairly narrow 

species that Weller referred to Bellerophon despite the 

presence of faint longitudinal lirae on parts of the holotype. These lirae show on a plaster impression of this 

specimen that we examined. Topotypes of this species 

in the USGS collection show that it has a faint delicate 

cancellate ornamentation. Characteristic of this species is the parabolic whorl section and the rounded longitudinally threaded selenizone that is slightly more 

convex than the general curvature of the whorl.

Bucanopsisperelegans var. minima Beede, from beds 

presumably of the Windsor Group on Coffin Island, 

Magdalen Islands, Quebec, is probably Late Mississippian in age. In general shape, it resembles Weller's 

figure of Bucanopsis perelegans White and Whitfield, 

but that is the only close similarity. We regard it as a 

valid species of Retispira. The shells are tiny, about 

3 mm long but relatively wide, and have a delicate cancellate sculpture at either side of a very narrow raised 

selenizone. According to Beede, 16 or 17 fine spiral 

threads occur in the space of 1 mm, and 10 collabral 

lirae in the same space. Like R. textilis (Hall), this 

species tends to form nodes at the intersections of the 

spiral and collabral lirae.

Another Canadian species, Bucanopsis beedia Bell, 

from the upper beds of the Windsor Group of Nova 

Scotia, comes from rocks now regarded as early 

Namurian (middle Chesterian) in age. This species also 

belongs in Retispira. It has a broadly expanded whorl 

bearing a raised flat-topped selenizone. The ornamentation is of fine closely spaced lirae of unequal strength, 

crenulated microscopically by growth lines and crossed 

by a few broader sulci of growth; about eight lirae occur 

in the space of 1 mm. Until the relative stratigraphic 

position of R. minima is known and young shells of R. 

beedia are studied, one cannot say certainly that R. 

minima is not just an immature R. beedia.

Five previously described species from Chesterian 

rocks in the United States complete the roster of North 

American Mississippian species of Retispira. Three of 

them, R. nolani Gordon and Yochelson and R. albapinensis Gordon and Yochelson, both described from the 

Diamond Peak Formation in Nevada, and R. eliasi n. 

nom., from the Redoak Hollow Member of the Goddard 

Shale, are discussed elsewhere in this report. Bucanopsis ornatus S. Weller, from the basal part of the Okaw 

Limestone of Illinois, has a broad globose shell on 

which the selenizone is not prominent but rather is 

slightly raised to very slightly depressed and gently 

convex. The collabral ornamentation in this species is 

also very obscure. The spiral ornamentation, although 

it includes lirae and threads of first through third orders, is rather widely spaced. Further details have been 

given by Thein and Nitecki (1974, p. 51-55).

Bellerophon missouriensis Swallow was never figured and remains unrecognized since its original description. The description is sufficient to identify it as 

a cancellate carinate bellerophontacean, which 

prompts us to transfer it to Retispira but does not distinguish it from other species of this genus. Why Swallow (1863, p. 100) would propose B. missouriensis as the 

name for a shell that "is common in the upper beds of 

the Archimedes Limestone at Chester, Illinois" and 

was not cited from anywhere else is not clear. No doubt, 

this specimen was destroyed, along with other Swallow 

types, in the fire at the University of Missouri in 1892. 

We believe that there is no likelihood of ever recognizing Swallow's species and recommend that the name be 

limited to use with the missing type lot.

Nomenclatural note. A new name, Retispira eliasi 

n. nom., is here proposed to replace Bucanopsis 

(Retispira?) reticulata Elias (1958, p. 3, 4, pi. 1, figs. 

5-7), which is a junior secondary homonym of 

Bellerophon reticulatus McCoy (1844, p. 25, pi. 2, fig. 5). 

The species described by Elias and by McCoy are obviously distinct, but both belong in Retispira as interpreted here.

We examined the types of R. eliasi, which consist of 

eight incomplete external molds in limonitic sandstone 

(Univ. Oklahoma colln. 7062). This species is rather 

small, its diameter at maturity less than its width. The 

selenizone has the same gently convex curvature in 

cross section as the rest of the shell. The sculpture 

consists of closely spaced spiral lirae of two or three 

ranks crossed by somewhat wider spaced steplike collabral lirae, having finer threads interspersed, which 

are broadly convex anteriorly at either side of the 

rather narrow lunulae. Elias (1958, pi. 1, fig. 5) designated one of the figured fragments as the holotype.

Retispiras from three collections in the Chainman 

Shale could not be identified to species and are listed as
SYSTEMATIC PALEONTOLOGY 41

Retispira sp. indet. These specimens are from USGS 

collections 15161-PC (4), 17214-PC (1) and 25566-PC

(1).

Retispira cincta n. sp.

Plate 2, figures 32-35

Diagnosis. Bellerophontacean having wellrounded whorl profile and reticulate ornamentation bisected by beltlike convex selenizone, covered with fine 

longitudinal lirae and studded with coarse lunulae.

Description. Shell expanding uniformly, not geniculate, narrowly and deeply phaneromphalus; margin of 

umbilicus well rounded and not set off from flanks, 

umbilicus partly concealed by inner lip. Maximum 

shell width just beyond columellar area. Earliest 

growth stages unknown. Whorl profile changing gradually with growth, that of juvenile stage following approximate arc of circle, except for marked interruption 

at selenizone; profile of mature stage somewhat more 

arched, having dorsum less well rounded and accordingly height of selenizone not quite as marked. Selenizone moderately broad, strongly convex, raised and 

prominently weltlike in younger stages; also convex at 

maturity but not so obviously set off from overall curvature of dorsum. Slit depth not known. Growth lines 

straight, orthocline in upper part of umbilicus and 

across flanks, arching gradually in vicinity of selenizone to form 70° angle with it. Details of aperture unknown. Inductura present, probably extending short 

distance out of aperture, moderately thin across dorsum and flanks, only slightly thicker in columellar 

area.

Collabral ornamentation consisting of fairly coarse 

lirae, asymmetrical in cross section and having the 

steeper side toward the aperture; lirae are fairly closely 

spaced and interspersed with sparse threadlike growth 

lines. Approximately 15 prominent spiral lirae present 

on dorsum and flanks on each side of selenizone in 

early stages, intersecting collabral lirae to form pattern of tiny squares or transverse rectangles, secondorder lirae and finer threads being scarce at this state. 

During growth, number and strength of spiral lirae 

increase, pattern becoming one of longitudinally elongate rectangles. Selenizone ornamented by coarse wellformed lunulae, irregularly spaced and interspersed 

with fine threadlike lunulae, and as many as 13 

equally fine spiral threads. In mature shell, total number of spiral lirae about 80.

Dimensions. Holotype, a mature specimen lacking 

part of final whorl, measures 10.7 mm in length, 10.3 

mm in width, and 7.1 mm in height (at right angles to 

length).

Discussion. This species is based upon three specimens, all from the Goniatites granosus Zone. The holotype, from the Granite Mountain section, is fairly complete and preserves in detail the sculptural features. 

The paratypes are from two localities in the Foote 

Range area, on the western side of the Bishop Springs 

dome.

The distinguishing feature of this species is the convex, longitudinally lirate lunulae-studded selenizone. 

The convexity of the selenizone distinguishes it from 

those of the Chainman forms, R. ordinata n. sp., R. sp. 

A, and R. sp. B, all of which have flat- or nearly flattopped selenizones. The only other Chainman species 

having a convex selenizone isR.jensenensis n. sp., but 

that species lacks the coarse lunulae that give the selenizone of R. cincta its beltlike appearance. R. cincta, 

likewise, is broader and has somewhat more rounded 

flanks than does R. jensenensis.

R. monroensis (S. Weller), from the Ste. Genevieve 

Limestone in Monroe County, 111., has a slightly raised 

convex selenizone, bearing inconspicuous ornamentation. The shell seems to be slightly more compressed at 

maturity than that of R. cincta, but, because of insufficient comparative material, we cannot be certain of 

that detail. Both spiral and collabral ornamentation 

are more closely spaced in Weller's species. R. minima 

(Beede) is superficially similar in having a raised selenizone but differs in being flat topped, in lacking 

prominent lunulae, and in having a wider shell.

Although R. waverliensis (Hyde) is somewhat similar in shape to R. cincta, the ornamentation is strikingly different. The Chainman species emphasizes the 

collabral element, does not have a square reticulation, 

and the lunulae are stronger.

Types. Holotype USNM 210937; paratypes USNM 

210938, 210939.

Occurrence and number of specimens. USGS collections 17012-PC (1), Juab County; 17250-PC (1), 

20446-PC (1), Millard County.

Retispira ordinata n. sp.

Plate 2, figures 22-29

Diagnosis. Bellerophontacean having cancellate 

ornamentation supplemented by third- and fourthorder spiral lirae; selenizone flat, set off by narrow 

sulci.

Description. Shell uniformly coiled, not geniculate; 

whorl profile simple, in early whorls approximately following evenly curved arc from umbilical areas outward 

and upward, then curving smoothly inward; curvature 

interrupted only slightly by selenizone; sloping flanks 

becoming flatter and dorsum narrower and flatter at 

maturity. Selenizone generally flat, set off from main 

body of shell by narrow, shallow longitudinal depressions, slightly raised above surface of whorl in juvenile
42 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

specimens, flush to slightly depressed in maturity. 

Shell anomphalous, but having umbilical depressions 

that become fairly deep in mature stage. Lip not known 

in detail; inner part appearing subparallel to axis of 

coiling and apparently staying approximately in one 

plane as it swings forward, so that little sinuousity 

develops in columellar area. Growth lines numerous, 

approximately orthocline from umbilical area to a 

point about five-sixths distance from umbilical area to 

selenizone, then curving prosocline to approach selenizone at angle of about 45°.

Surface ornamentation complex, of several intersecting elements. Collabral ornamentation of low rounded 

costae becoming somewhat lamellose and less regularly spaced near aperture, together with sublamellose 

growth lines between costae, more prominent than normal growth lines of fine threadlike size. Longitudinal 

lirae also of several sizes, including 15 or 16 of primary 

and secondary orders crossing transverse costae to 

form network pattern; intercalated with these are 

threads of third and fourth orders, the finest approximating size of growth lines; quatrordinal arrangement 

best developed on dorsolateral areas; areas immediately adjacent to selenizone and around umbilical depressions limited more to smaller size threads. Selenizone ornamented by well-formed lunulae, including 

some prominent lunulae in semiregular pattern, separated by numerous finer ones; 11 very fine longitudinal 

threads also present on selenizone, central thread 

slightly coarser than others. Total of longitudinal elements of all sizes on specimens ranging roughly from 

150 to 180.

Inductura smooth, prominent, extending out of aperture to point where its edge forms right angle with 

outer lip, this edge being nearly orthocline across shell; 

inductura thin outside of aperture and on columellar 

walls but thickened over dorsum of penultimate whorl 

so that in profile inner part of whorl appears geniculate.

Dimensions. Holotype measures 17.5 mm in 

length, 17.5 mm in width (twice half width), and 11.0 

mm in height (at right angles to length); slit depth is 

5.5 mm.

Discussion. This species is based upon specimens 

from the Paracravenoceras barnettense Zone in the Burbank Hills. Ten specimens are present in three collections from a shale bed containing small limestone nodules in which Glabrocingulum hosei n. sp. is very 

abundant.

Retispira ordinata is easily recognized by its fairly 

broad shell, flat selenizone set off by bordering narrow 

sulci, and the spiral lirae and threads of four distinct 

sizes. R. cincta n. sp. and R. jensenensis n. sp. have

narrower shells with convex selenizones and fewer 

coarser spiral lirae. The unnamed R. sp. also has a flat 

selenizone, but this is not set off by bordering sulci. 

Furthermore, the spiral lirae are fewer and coarser.

Specimens of R. ordinata change in whorl profile 

from moderately globose in the immature and early 

mature shell to, by full maturity, a gabled (fastigiate) 

dorsum having a narrow flattened zone on top and 

nearly flat sloping flanks. Two fairly large paratypes 

from the Paracravenoceras barnettense Zone in the 

Needle Range show this character.

Early mature specimens of this species might be confused with fully mature specimens of Retispira michiganensis (Winchell). A comparison with probable topotypes of WincheH's species, from Battle Creek, Midi., 

shows that the two species at the same size are generally similar in shape. First- through third-order spiral 

lirae are present on the dorsum and upper flanks of 

R. michiganensis, but the presence of fourth-order 

threads is not certain. The principal difference between 

the two species, aside from the smaller size of R. michiganensis and its lack of a fastigiate stage, lies in its 

much finer and more closely spaced collabral ornamentation. In contrast, the early mature shell of R. ordinata has coarser, more ridgelike collabral elements.

Retispira ornata (S. Weller) differs from R. ordinata, 

which occurs in rocks of about the same age, in its more 

obscure selenizone and collabral ornamentation, rather 

widely spaced spiral lirae, and more inflated whorl profile. R. textilis (Hall) has a generally flush or only 

slightly raised selenizone, as does R. ordinata, but this 

is not set off by sulci. Moreover, the ornamentation is 

more coarsely cancellate in Hall's species, even though 

third-order spiral threads may be present. Hall's description mentions 30 longitudinal lirae at either side 

of the selenizone, about half the number normally 

present in R. ordinata. R. textilis neither reaches the 

size of R. ordinata nor develops the fastigiate whorl 

profile in late maturity.

R. eliasi n. nom. from Oklahoma has a broad, evenly 

rounded whorl profile not interrupted by the selenizone 

in contrast to the somewhat irregular curvature of 

R. ordinata. The Oklahoma shell also differs by not 

developing fourth-order spiral threads and in having 

finer, more subdued collabral threads that are generally absent on the flanks. Furthermore, in R. ordinata, 

the selenizone bears only fine spiral threads and is 

clearly set off from the rest of the dorsum, whereas in 

R. eliasi, the selenizone has three fairly strong spiral 

lirae and two alternating finer threads, the ornamentation of the selenizone thus being similar to that of the 

dorsum and upper flanks.

Types. Holotype USNM 210940; paratypes USNM 

210941-210945.
SYSTEMATIC PALEONTOLOGY 43

Occurrence and number of specimens, USGS collections 15157-PC (3), 17187-PC (2), 17194-PC (2), 

25264-PC (6), Millard County.

Retispira nolani Gordon and Yochelson

Plate 2, figures 18-21

Retispira nolani Gordon and Yochelson, 1983, p. 976-

977, figs. 1 O-Q.

Discussion. This species occurs in the Burbank 

Hills, but the primary types are from White Pine 

County, Nev. Two of the three Utah specimens are illustrated on plate 2. R. nolani is easily distinguished 

from most species of Retispira in the Chainman Formation by its broad shell. Its flat selenizone distinguishes 

it from R. cincta, which also has a broad shell.

R. ordinata n. sp., the species most like R. nolani, 

likewise has a flat selenizone and might have been the 

progenitor of R. nolani. R. ordinata can be distinguished by the somewhat fastigiate whorl profile in 

mature specimens, its flattened sloping flanks contrasting with the rounded flanks ofR. nolani. At comparable growth sizes, the collabral ornament and selenizone are more prominent in R. ordinata. In 

R. nolani, fewer spiral elements are present, but they 

are more uniform in size and generally are more prominent than in R. ordinata. This is reflected in the selenizone, which in R. ordinata normally is ornamented by 

11 lirae or threads and in R. nolani, by five. A more 

prominent boss also is present within the aperture of 

R. nolani.

At the type locality in east-central Nevada and in the 

Burbank Hills, R. nolani is restricted to the Crauenoceras hesperium Zone. At all the localities where it has 

been found, specimens are associated with this ammonoid.

Figured specimens. USNM 210951, 210952.

Occurrence and number of specimens. USGS collections 17095-PC (1) Juab County; 17188-PC (1), 

17189-PC (1), 17310-PC (1), 725319-PC (1), 

725551-PC (2), Millard County.

Retispira jensenensis n. sp.

Plate 2, figures 12, 13

Diagnosis. Moderately phaneromphalous bellerophontacean having gently sinuate aperture; spiral ornamentation predominant on convex selenizone.

Description. Shell evenly coiled, not geniculate, 

somewhat compressed, moderately phaneromphalous; 

umbilical walls nearly vertical, rounding fairly 

abruptly into flanks but without circumbilical angulation. Greatest shell width immediately adjacent to umbilical area. Early growth stages unknown; whorl profile narrowly arched in juvenile shell, approaching 

shape of a pointed arch; mature profile more inflated 

and rounded dorsally. Selenizone continuous with profile of dorsum in early stages but conspicuously convex 

in more mature stages, nearly semicircular in cross 

section. Growth lines straight, orthocline adjacent to 

umbilicus and gently sigmoidal on upper flanks and 

dorsum, having adaperturally bowed segment at middorsum; juncture with selenizone at angle of approximately 80°. Slit depth unknown; other apertural details lacking.

Collabral ornamentation of closely spaced, slightly 

asymmetrical lirae; finer threads not visible. Spiral ornamentation of about 25 first-order lirae on each side of 

selenizone, more or less uniformly spaced along dorsum 

and flanks, interspaces three or four times width of 

lirae but more closely spaced in umbilical area. As 

many as 40 first- and second-order lirae may be present 

at either side of selenizone. Intersection of collabral 

and spiral elements forming fine reticulate pattern 

over most of shell surface, beaded adjacent to umbilici. 

Selenizone ornamented by about seven to nine fairly 

coarse spiral threads; lunulae not apparent. Parietal 

inductura present, details unknown.

Dimensions. Incomplete holotype has dimensions 

(in mm) as follows: length 6.3, width 5.2, height (at 

right angles to length) 5.1.

Discussion. The holotype of this species is a wellpreserved but incomplete shell from the upper part of 

the Cravenoceras hesperium Zone in the Jensen Wash 

section, Burbank Hills. A specimen from the Indian 

Pass section, having slightly coarser longitudinal 

sculpture, is included.

The convex selenizone marks Retispira jensenensis 

as distinct from R. ordinata, R. nolani, and R. sp. Although the shape of its selenizone is similar to that in 

R. cincta, it lacks the prominent lunulae that identify 

that species. Well-preserved specimens of both species 

are generally similar in ornamentation, but their 

whorl profiles are distinct, that of R. jensenensis being 

narrower and more highly arched.

Types. Holotype USNM 210946; paratypes USNM 

348021, 363082.

Occurrence and number of specimens. USGS collections 17003-PC (1), 17188-PC (1), 17189-PC (1), Millard County.

Retispira stenopsis n. sp.

Plate 2, figures 7, 8

Diagnosis. Compressed bellerophontacean having 

weltlike selenizone; profile in cross section trending 

toward weak ventrolateral shoulders; shell ornamented by fine spiral lirae.
44 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Description. Shell narrow, having low rate of expansion. Nucleus and early growth stages unknown. 

Umbilici prominent, wide and deep; umbilical walls 

evenly convex. Whorl profile with periphery just above 

umbilici, curving upward and ever more gently inward 

from periphery in low, increasingly flattening arch. At 

mid-dorsum, wide raised welt, hemisperical in cross 

section, is formed by selenizone. Details of inner and 

outer lips unknown; incomplete margins suggesting 

extension of lateral lips outward, partially obscuring 

umbilici.

Slit depth unknown, but less than one-fourth circumference of whorl and probably much shorter; selenizone 

at mid-dorsum strongly arched upward, slightly raised, 

occupying essentially entire width of welt; lunulae obscure or absent. Ornament of fine closely spaced spiral 

lirae, subequal in width, though varying irregularly 

across dorsum, rounded in profile; interspaces narrower than lirae; collabral lirae exceedingly fine and 

generally obscure, an occasional thread visible at wide 

irregularly spaced intervals. Inductura thin, not extending outside aperture.

Dimensions. Holotype, lacking outer margins of 

aperture, measures (in mm): length 12.8, width 9.2, 

depth 9.2.

Discussion. Retispira stenopsis is one of the more 

distinctive species of Bellerophontacea in the Chainman gastropod fauna and is characterized especially by 

its predominance of spiral lirae as well as by its steeply 

sloping flanks. Retispira jensenensis, also a narrow 

species having a convex selenizone, is distinguished 

from R. stenopsis by its much more prominent collabral 

sculpture and by the fact that its selenizone is not weltlike, but narrowly rounded at the apex of a gothic-arch 

profile so that it is continuous with the flanks.

Retispira nolani is more globose in outline and has a 

narrower selenizone; this selenizone is slightly raised 

but not weltlike as in R. stenopsis. R. ordinata is also 

wider and has a flattened selenizone, smaller umbilici, 

and prominent reticulate ornament. The single specimen compared with R. textilis (Hall) is wider and also 

shows prominent reticulate ornament similar to that of 

R. ordinata.

Perhaps the species most like R. stenopsis in the 

Chainman Shale is R. cincta. It, too, shows a weltlike 

raised selenizone. Its ornament, however, is somewhat 

cancellate, having fairly strong collabral lirae rather 

than only closely spaced spiral lirae. More subtle differences are seen in whorl profile, in that the umbilici of 

R. cincta seem to be slightly smaller and the shell 

slightly wider, resulting in a less archlike profile. The 

strong lunulae of R. cincta also are distinctive.

All the specimens of R. stenopsis are from a single 

locality on the northeast side of Jensen Wash, Burbank

Hills; they occur in the Rhipidomella nevadensis Zone 

within the range of the brachiopod Carlinia phillipsi 

(Norwood and Pratten).

Types. Holotype USNM 210947; paratypes USNM 

210948-210950, 211087.

Occurrence and number of specimens. USGS collections 17059-PC (21), 17217-PC (5), 25548-PC (12), 

28612-PC (6), Millard County.

Retispira cf. R. textilis (Hall)

Plate 2, figures 30, 31, 36

Bellerophon textilis Hall in Miller, 1877, p. 243. 

Knightites (Retispira) textilis (Hall). Yochelson and

Saunders, 1967, p. 116 (see for full synonymy).

Discussion. A sixth species of this genus is represented in the Chainman Shale by a steinkern, 9 mm 

long, that retains part of the shell; it is from the top of 

the Goniatites americanus Zone of late Meramecian age 

in the Granite Mountain section and is the oldest representative of this genus in the fauna. Although the specimen is not complete enough to identify with certainty, 

the characters preserved are shared by the American 

Midcontinent species R. textilis (Hall), and none differentiate it from that species.

This Utah specimen has a smooth well-inflated profile, unlike the narrower R. jensenensis n. sp. Judging 

from the absence of any interruption in the curvature 

of the dorsum on the steinkern, the selenizone seems to 

have been flush; this feature serves to dintinguish R. 

cf. R. textilis from R. cincta n. sp., which shows a general similarity in shape. A patch of shell retaining the 

ornament is present in the columellar area, and the 

intersections of transverse and collabral elements are 

nodose or pustulose adjacent to the inner lip. The pattern appears rather coarsely cancellate in contradistinction to the fine predominantly spiral lineation in 

the umbilical area of R. ordinata n. sp. The ornamentation is more like that of R. cincta than any other Chainman species, but in R. cincta, the cancellation is a little 

finer and is not pustulose at the intersections. A thin 

inductura is present.

In only two Mississippian species are the intersections of spiral and collabral lirae reported to show a 

tendency to develop tiny nodes or pustules. These are 

R. textilis (Hall) and R. minima (Beede). The latter 

species, from eastern Canada, is based on tiny specimens that are much wider than R. textilis and the 

Chainman specimen.

Walcott (1884, p. 257, pi. 18, fig. 18) figured as 

Bellerophon textilis Hall? a specimen from the Diamond Peak Formation at Conical Hill, near Eureka, 

Nev. The beds at this locality are also late Meramecian 

in age. We have examined this lot of four specimens (a
SYSTEMATIC PALEONTOLOGY 45

fifth is a. Bellerophon) under USNM 14421. These specimens, which clearly belong in Retispira, range in 

length from about 17 to 23 mm and appear rather 

coarsely cancellate. One of them shows some tiny pustules at the intersections of the spiral and collabral 

lirae. The specimens are preserved in calcareous sandstone, and all are at least partly distorted. Their large 

size and poor preservation preclude direct comparison 

either with the Chainman Shale specimen or typical 

examples from the Midcontinent. Nevertheless, we feel 

that Walcott's questioned specific determination 

should stand.

Figured specimen. USNM 210936.

Occurrence. USGS collection 17018-PC, Juab 

County.

Retispira sp.

Plate 2, figures 16, 17

Discussion. One small incomplete specimen, 4.4 

mm long, from a bed containing Richardsonites merriami (Youngquist) in the Conger Range, shows that still 

another species of Retispira is present in the upper part 

of the Chainman Shale. The specimen is globose and 

has relatively deep umbilical depressions. Ornamentation consists primarily of two sizes of alternating spiral 

lirae; collabral ornamentation is less obvious. The selenizone is narrow and flush with the dorsum; lunulae 

are obscure, and the selenizone of this immature individual can be distinguished only with difficulty on the 

ornamented dorsum; it is not set off by bordering shallow grooves as in R. ordinata n. sp. The inflated shape 

distinguishes it from R. nolani.

Figured specimen. USNM. 210953.

Occurrence and number of specimens. USGS collections 22880-PC (1), 25319-PC (1), Millard County.

Suborder PLEUROTOMARIINA 

Superfamily PLEUROTOMARIACEA

Discussion. Since the last major revision of Paleozoic gastropod classification (Knight, Batten, and 

Yochelson, 1960), much additional information on the 

Pleurotomariacea has accumulated, including descriptions of new genera and reassignment of taxa already 

in the literature. It has become increasingly difficult 

for new concepts of the significance of various mophologic features to be used within this older classification. 

In the Pleurotomariacea, primary and nearly exclusive 

emphasis on the position of the selenizone has not stood 

the tests of time and use and seems to us to be an 

unsatisfactory factor for major grouping.

We think that subdivisions within the Pleurotomariacea depend upon several factors that should be assigned nearly equal weight. Not only is the position of 

the selenizone on the whorl important, but its position 

relative to immediately adjacent parts of the whorl profile should be considered. Furthermore, whether the 

selenizone is broad or narrow, distinctly flattened, concave, or convex may be just as significant as its position. Arrangement by selenizone position alone, without reference to general shell shape, has resulted in a 

classification that has produced some rather strange 

bedfellows seemingly similar shells that other criteria would not find at all closely related. We conclude 

that the proportions and curvatures of the whorl surface and its parts cannot be considered simply as 

generic features but should be given greater emphasis 

in defining higher categories.

As a consequence of our study, we have modified the 

1960 classification of the pleurotomariaceans in several aspects. However, we confined our investigations 

almost exclusively to Carboniferous genera that occur 

in the Chainman Shale, or to closely related taxa. In no 

way should our systematic modifications be considered 

a full revision of the superfamily. Study of both older 

and younger genera will determine whether or not our 

proposed revisions are a step forward in understanding 

this complex superfamily.

Family SINUOPEIDAE 

Subfamily TURBONELLININAE

Genus RHINEODERMA Koninck, 1883 

Rhineoderma? sp.

Discussion. This record is based upon a crushed 

specimen of pleurotomariacean from dark-gray silty 

limestone below the base of the marker bed (Skunk 

Spring Limestone Member of Sadlick, 1966) in the 

measured Chainman Shale section at Granite Mountain. This specimen is nearly flattened, 23.5 mm in 

diameter, and preserves much of the final whorl from 

suture to selenizone. The approximately 12 to 13 spiral 

lirae on the upper whorl surface are crossed by weaker 

and more closely spaced, gently sigmoidal prosocline 

radial lirae. Near the selenizone, the radial lirae curve 

more strongly backwards, suddenly reversing direction 

and forming fine lunulae at the selenizone. At the intersection of the spiral and radial lirae, small interference nodes are present. The base is obscured but seems 

to be similar to the upper whorl face in ornamentation.

The ornamentation of this species is close to that of 

Rhineoderma pealeanum (Girty), particularly Girty's 

paratype, which is larger than the holotype and has a 

diameter of 14.5 mm. The Granite Mountain specimen 

lacks the spire, so we feel it necessary to question even 

the generic assignment. Nevertheless, the sculpture is
46 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

so close to that of Rhineoderma that we can think of no 

other genus in which to place it. This gastropod is 

stratigraphically the lowest one yet found in the Chainman Shale in western Utah; it is Meramecian in age.

Described specimen. USNM 388227.

Occurrence. USGS collection 28637-PC, Juab 

County.

Family RAPHISTOMATIDAE

Subfamily LIOSPIRINAE 

Genus TREPOSPIRA Ulrich in Ulrich and Scofield, 1897

Subgenus T. (ANGYOMPHALUS) Cossman, 1916

Discussion. This subgenus differs from the typical 

one in having subsutural radial ridges ornamenting 

the upper whorl surface and in having an open umbilicus. The earliest of the Chainman species has these 

characters and also shows radial wrinkles or lirae rimming the umbilicus.

American Mississippian species o/Trepospira (Angyomphalus). 

1 discus Girty, 1910

excavata (Easton), 1962 (Angyomphalus?)

penelenticulata Rollins, 1975

regularis n. sp.

Trepospira (Angyomphalus?) discus Girty from the 

Fayetteville Shale of Arkansas is placed here provisionally; it is an extremely depressed form and was 

based upon a poorly preserved holotype. The umbilical 

area on this shell is moderately wide, but one cannot 

determine whether or not the umbilicus was open; also, 

no radial subsutural riblets are visible on the upper 

whorl surface.

T. (A.)penelenticulata Rollins from the Wassonville 

Limestone of Iowa is the earliest known form. 

Depressed-lenticular in shape, it has faint subsutural 

threads and a narrow selenizone.

T. (A.) excavata (Easton) from the Heath Shale of 

Montana, is widely umbilicate, has well-developed subsutural radial ridges, and certainly belongs in this subgenus. Another shell, from the Lower Mississippian in 

northern Alaska, was described by Yochelson and 

Dutro (1960, p. 136) as Trepospira (Angyomphalus?) 

sp. Although immature, it clearly possesses the characters of this subgenus.

We do not follow Thein and Nitecki (1974, p. 18) in 

referring Trepospira (Angyomphalus) kentuckiensis 

Thein and Nitecki and Mourlonia? stellaeformis Hyde 

to this subgenus. T. (A.) kentuckiensis we regard as a 

Mourlonia and M. ? stellaeformis as belonging in 

Glabrocingulum (Glabrocingulum). They are discussed 

under those genera.

Trepospira (Angyomphalus) regularis n. sp.

Plate 3, figures 19-26

Diagnosis. Depressed lenticular, narrowly 

phaneromphalous pleurotomariacean gastropods; shell 

ornamented by short subsutural ridges.

Description. Low-spired shell having pleural angle 

of approximately 145°. Nucleus unknown. Early whorls 

having slightly higher spire and slightly more inflated 

upper whorl surface than more mature stages, and at 

least two of them unornamented. Sutures distinct, 

smooth. Upper whorl surface of final whorl having narrow flattened zone immediately adjacent to suture, inclined so as to embrace penultimate whorl just above 

periphery; remainder of upper whorl surface simple, 

gently arched downward with curvature increasing toward periphery. Periphery bluntly rounded. Basal 

whorl surface curving inward and downward from periphery, flattening slightly just before reaching 

rounded margin of umbilical area. Umbilicus poorly 

known but definitely phaneromphalous, narrow, not 

covered with inductura; a narrow spiral cord present 

within depressed area.

Growth lines faint, closely spaced so that shell surface appears smooth and almost polished; their course 

orthocline from suture for about one-third of distance 

across upper whorl surface, then sweeping prosocline to 

upper edge of selenizone, joining at an angle of about 

45°; below selenizone, growth lines curving 

opisthocline to umbilical area; growth lines unknown 

within umbilicus. Outer lip not known. Selenizone relatively wide, it upper edge far up on upper whorl surface and its lower edge just below periphery, nearly 

flush with whorl surface except that upper edge is 

raised slightly; lunulae absent. Shell ornamented by 

band of elongate raised lirae normal to suture and extending from suture for about one-fourth total width of 

upper whorl surface; spacing increasing with size of 

shell, but showing some irregularity, a typical mature 

whorl bearing about 30 ridges. Radial ridges also 

present rimming umbilicus in immature shells. Shell 

thin, of at least two layers, the outer one extremely 

thin.

Dimensions (in mm). 

USNM 210964 210961 210962 210963

Height ..... 12.5 8.7 7.7 2.4 

Width ...... 23.8 15.1 13.3 4.0

Discussion. This species was found in a fossiliferous concretionary bed of the Goniatites americanus
SYSTEMATIC PALEONTOLOGY 47

Zone of the Granite Mountain section, just above the 

marker bed. The zone is regarded as latest Meramecian 

in age. Trepospira (Angyomphalus) regularis is easily 

distinguished from other Trepospira in higher beds in 

the Chainman Shale by its open umbilicus and its subsutural short radial ridges, some 30 on the final whorl. 

The two species of Trepospira (Trepospira} described 

below differ from T. (Angyomphalus} regularis in bearing 14 to 17 rounded subsutural nodes and in having 

the umbilical area covered by an inductura.

Trepospira (Angyomphalus} regularis n. sp. differs 

from both T.(A.} excavata (Easton) and T. (A.I} discus 

Girty in having both upper and lower surfaces of approximately the same convexity; the latter two species 

have the upper surface less convex than the lower. 

Moreover, T. (A.?) discus lacks radial ridges on the 

upper surface T. (A.?) sp. described by Yochelson and 

Dutro (1960, p. 136) from the Lower Mississippian of 

Alaska is an immature shell slightly more than 4 mm 

wide. Comparing it with our figured specimen of T. (A.} 

regularis at approximately the same size, we find that 

the Alaska specimen is more depressed, has more 

crowded and presumably more numerous subsutural 

riblets, and lacks the tiny radial riblets that ring the 

umbilicus in the immature Utah shell.

Types. Holotype USNM 210961; paratypes USNM 

210962-210965.

Occurrence and number of specimens. USGS collections 17018-PC (10), 25558-PC (4), Juab County.

T. (TREPOSPIRA) Ulrich in Ulrich and Scofield, 1897

Discussion. The typical subgenus is more characteristic of Pennsylvanian rocks; in fact, the two Chainman species described below are the first authentic 

Trepospira (Trepospira) from rocks of Mississippian 

age. This subgenus is distinguished from T. (Angyomphalus) by the presence of subsutural nodes rather 

than radial ridges and by having the umbilicus closed 

by a callus deposit.

Four previously named American species include T. 

(T.) discoidalis Newell from the Eudora Shale of Kansas; T. (T.) illinoiensis (Worthen), the most ubiquitous 

Pennsylvanian species; T. (T.) minima Hoare from the 

Seville Limestone and Robinson Branch Formation of 

Missouri; and T. (T.) sphaerulata (Conrad), the type 

species, described originally from western Pennsylvania.

We do not include in this subgenus T. (T.) chesterensis Thein and Nitecki from the Golconda Limestone of 

Illinois, the types of which we regard as immature representatives of Glabrocingulum (Glabrocingulum).

Trepospira (Trepospira) baconi n. sp.

Plate 3, figures 27-31

Diagnosis. Extremely low-spired cryptomphalous 

smooth pleurotomariacean gastropods having moderately large nodes near suture, of which 14 to 17 are on 

final whorl.

Description. Shell bluntly lenticular in cross section, extremely low spired, pleural angle near 140°. 

Nucleus simple, orthostropic; first three whorls lacking 

ornamentation and very slightly raised above general 

level of upper surface. Whorl profile narrowly parabolic 

from suture to lowest point of base, except for slight 

flattening at selenizone near edge of upper whorl surface; periphery rounded subacute; inner part of base 

curved very slightly upward to umbilicus. Umbilicus 

marked by sharp circumbilical angulation, forming 

nearly a right angle. Base cryptomphalous, umbilical 

depression partly filled by inductural deposit reaching 

almost to circumbilical angulation. Columellar lip 

straight, outer lip unknown.

Shell smooth, except for growth lines and subsutural 

nodes. Growth lines closely spaced but faint; unknown 

near suture, distinctly prosocline near middle of upper 

whorl surface and curving very slightly below this so as 

to form angle of approximately 45° with upper edge of 

selenizone; opisthocline below selenizone, forming 30° 

angle with lower edge of selenizone, then curving forward to lowest point on base and finally curving prosocline to form broad shallow prong. Selenizone flattened 

and broad inclined at about 45° to axis of coiling; upper 

edge distinctly raised above whorl surface; lower edge 

at periphery, not set off from base; lunulae absent, 

growth lines on selenizone as obscure on those on upper 

surface of shell. Whorl ornamented by nodes immediately subsutural in position, circular in cross section 

and rising to a rounded tip, uniformly spaced, interspaces only slightly wider than nodes. Nodes seemingly 

at an approximately logarithmic spacing; mature 

whorl bearing about 15 nodes.

Dimensions. Holotype measures 11.5 mm in height 

and 23.2 mm in width.

Discussion. Trepospira (Trepospira) baconi is the 

earliest known species of the typical subgenus of Trepospira. The type lot is from three collections made 

from the same locality in the Burbank Hills. This locality in the lower middle part of the Chainman Shale has 

also yielded Glabrocingulum (Glabrocingulum) hosei 

n. sp., Hematites barbarae Flower and Gordon, and 

Paracravenoceras barnettense (Plummer and Scott) and 

is of middle Chesterian (early early Namurian) age 

correlated with the lower Eumorphoceras (Ej) Zone.
48 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

The species is a strongly depressed form, resembling 

the common T. (T. ) illinoiensis (Worthen) in shape. It 

can be distinguished from the four presently known 

Pennsylvanian species by the wide spacing, relatively 

large size, and small number of subsutural nodes; the 

numbers of nodes on the final whorl of each of these 

species are given in the comparisons under T. (T.) diadema n. sp.

This species is named for C. S. Bacon, Jr., who published, in 1948, the first study on the geology of the 

Confusion Range, Utah.

Types. Holotype USNM 210966; paratypes USNM 

210967-210969, 364701.

Occurrence and number of specimens. USGS collections 15166-PC (1), 17187-PC (1), 17194-PC (2), 

25264-PC (3), 28610-PC (1), Millard County.

Trepospira (Trepospira) diadema n. sp.

Plate 3, figures 32-36

Diagnosis. Pleurotomariacean gastropods having 

low-spired cryptomphalous smooth shell ornamented 

by a subsutural ridge bearing small nodes.

Description. Shell depressed, sublenticular, having 

lower surface slightly more convex than upper, of approximately six whorls including nucleus. Nucleus of 

uncertain size, orthostrophic. Early whorls smooth, 

convex, slightly higher spired than more mature part of 

shell. Characteristic subsutural ornamentation appearing at approximately end of third whorl, at same 

stage as increase of pleural angle, which reaches 125° 

at maturity. Body whorl embracing penultimate whorl 

between periphery and upper edge of selenizone. Sutures smooth, not impressed, although presence of subjacent ridge causes suture to appear impressed. Mature 

whorl profile adjacent to suture horizontal for an exceedingly short distance, then rising to cross narrow 

ridge; between outer edge of ridge and selenizone, profile forming very gently parasigmoidal curve, verging 

on flattened; upper whorl suface interrupted near periphery by upper (inner) edge of slightly raised selenizone; periphery subangular and located just within 

lower edge of selenizone; profile convex below periphery, having exceedingly faint change in slope at lower 

edge of selenizone, curving downward and inward in 

gradually reduced curvature toward columellar area; 

columellar depression absent or very shallow. Base 

cryptomphalous, probably consisting of thin inductura 

over anomphalous base. Shell smooth except for growth 

lines and subsutural ridge. Growth lines gently 

opisthocline to prosocline near suture, bowing toward 

aperture and recurving strongly near selenizone; similar on base but orthocline near columellar area, forming narrow arch over selenizone. Slit depth unknown.

Subsutural ridge nodose; 16 nodes on final whorl of 

holotype; nodes small, tending to be elongate parallel 

to ridge; interspaces about three times width of nodes 

in intermediate growth stages, but narrowing as nodes 

become longer with increasing maturity. Some shells 

having shallow depressions on upper whorl surface 

below subsutural ridge, coordinate with interspaces between nodes.

Dimensions. The holotype is 6.2 mm high and 12.8 

mm wide. A large paratype is 12.0 mm high and 23.4 

mm wide.

Discussion. This species is fairly common in a 15- 

foot (4.6-m) thickness of brown shale at or near the top 

of the Cravenoceras hesperium Zone in the Burbank 

Hills; it also occurs sparingly above and below this 

unit. It seems to be restricted roughly to the upper 600 

feet (183 m) of the formation in this area. The type lot 

was collected by J. E. Welsh along with the types of 

Bellerophon (Bellerophon) welshi n. sp. (USGS colln. 

17310-PC).

Trepospira (Trepospira) diadema differs from T. (T. ) 

baconi n. sp. in having a gently parasigmoidal to flat 

upper whorl surface at maturity, smaller nodes on the 

subsutural ridge, a better defined selenizone, a more 

acute periphery and a very shallow umbilical depression or none at all, in contrast to the convex upper 

whorl surface, large nodes, very subdued selenizone, 

more rounded periphery, and fairly deep umbilical depression of the earlier species.

T. (T. ) diadema is similar in shape to the widespread 

Pennsylvanian species T. (T.) illinoisensis (Worthen) 

(see Yochelson and Saunders, 1967, p. 236, 237, for 

synonymy). That latter species, however, has gently 

convex whorls, more nodes on the final whorl (17 to 24 

on the hypotypes that Girty (1915a, p. 158) described as 

Trepospira depressa (Cox) and 27 to 29 on specimens 

described by Hoare (1961, p. 149)), more rounded 

lunulae in the selenizone, and a relatively deep umbilical depression, all of which serve to distinguish it from 

T. (T.) diadema.

Another Pennsylvanian species, T. (T.) discoidalis 

Newell from Kansas, resembles T. (T. ) diadema in having a concave zone just below the subsutural ridge, but, 

as the spire in Newell's species is somewhat higher, the 

concavity is slightly more accentuated. These two species are also distinguished by the presence of a moderately deep umbilical depression and many more subsutural nodes (25 to 40 on the final whorl in the type lot) 

on the Kansas species.

The type species of the subgenus, T. (T. ) sphaerulata 

(Conrad), is characterized by its relatively higher spire 

and numerous, closely spaced subsutural nodes. T. (T. ) 

minima Hoare differs in having radially elongate lirae 

on the early whorls, lirae that become nodes by the
SYSTEMATIC PALEONTOLOGY 49

sixth volution; this volution bears 30 to 32 nodes. The 

umbilicus appears to be filled with a thin inductura, so 

this species, bearing lirae on its early whorls, cannot be 

referred to T. (Angyomphalus).

Types. Holotype USNM 210970; paratypes USNM 

210971-210975.

Occurrence and number of specimens. USGS collections 17021-PC (1), 17023-PC (1), 17056-PC 

(2 steinkerns), 17188-PC (1, 5 steinkerns), 17209-PC 

(1, 3 steinkerns), 17219-PC (14 steinkerns), 17310-PC 

(16, 23 steinkerns), 22883-PC (1), 25547-PC (4), 

25550-PC (8), 25551-PC (1), Millard County.

Trepospira (Trepospira) sp.

Plate 3, figure 18

Discussion. This record is based upon a single 

partly crushed shell from a bed containing Lunulazona 

sadlicki n. sp. in the section at Granite Mountain. Although the specimen has been depressed by crushing, 

its spire seems to have been moderately high. A tiny 

smooth nucleus of about 1V2 whorls is preserved at the 

apex of the shell. There are about 4V2 postnuclear 

whorls. The early whorls show faint low straight radial 

ribs, best preserved on the third whorl, where the ribs 

extend about halfway from the suture to the outer edge. 

The fourth whorl is poorly preserved. The final half 

whorl has 16 radially elongate elliptical nodes just 

below the suture.

Having radial ribs on the early postnuclear whorls 

and nodes on the mature part, this shell seems transitional from T. (Angyomphalus) to T. (Trepospira). We 

favor referring it to the latter subgenus because of its 

moderately high spire and the presence of nodes on the 

final volution.

Figured specimen. USNM 211027.

Occurrence. USGS collection 28628-PC, Juab 

County.

Subfamily OMOSPIRINAE 

Genus BAYLEA Koninck, 1883

Discussion. This genus includes subturbiniform, 

moderately high spired, turreted pleurotomariaceans 

having a narrow ramp adjacent to the suture and a 

narrow selenizone located at the outer edge of the sloping upper whorl face. The outer whorl face is steeply 

sloping and tends to be rather high; the base is well 

rounded and imperforate. Sculpture consists primarily 

of spiral cords; collabral lirae normally are weak. The 

shell from the Chainman Shale described below, although poorly preserved, has the turreted whorls typical ofBaylea.

North American Mississippian species included in 

Baylea. 

angulosa Rollins, 1975

coheni Yochelson, 1962

minuta (S. Weller), 1916 (Mourlonia)

sinuata (S. Weller), 1916 (Ptychompalus)

okawensis Thein and Nitecki, 1974

triftbra Rollins, 1975

Another Mississippian species was described as Baylea sp. from Sonora, Mexico (Knight, 1953, p. 74, pi. 8, 

C, figs. 15, 16), and Jerome Hill, Ariz. (Yochelson, 

1962, p. 78, pi. 17, fig. 8).

Baylea? sp.

Plate 7, figures 29, 30

Discussion. A unique specimen from the base of the 

Willow Gap Member of Sadlick (1966) in the Wallet 

Gulch measured section is referred questionably to 

Baylea. Like other gastropods in this bed, the shell is 

rather coarsely silicified. It consists of three whorls 

part of the spire is missing and measures 4.3 mm in 

length and 3.2 mm in width. The shell shape is similar 

to that of the type species Baylea yvanii Leveille, from 

the Tournaisian of Belgium, but the Utah specimen is 

considerably smaller.

A description of the Chainman species follows: The 

upper whorl face ofBaylea? sp. is narrow and sloping, 

nearly flat or slightly concave in profile; the outer 

whorl face is steep, vertical to slightly overhanging, 

and marked at the lower edge by an angulation approximately where the succeeding whorl attaches. The base 

slopes inward at about 45° and seems to be narrowly 

umbilicate; the aperture is somewhat trapezoidal because of the angulation but is suboval within. Whorls 

are ornamented by a few spiral lirae, but the exact 

number cannot be determined owing to the coarse silicification. Any collabral sculpture that might have 

been present has been obliterated.

The rather angular whorls in this species are somewhat reminiscent of Murchisonia and allied genera, 

but the whorls increase more rapidly in size than in the 

Murchisoniacea, and the apical angle is broader. Although this species cannot be identified with certainty, 

it is quite distinct from all other gastropods of the 

Chainman fauna.

Figured specimen. USNM 211070.

Occurence. USGS collection 25566-PC, Millard 

County.

Family EOTOMARIIDAE Wenz

Discussion. Since publication of the last major classification of Paleozoic Gastropoda (Knight, Batten, and 

Yochelson, 1960), opinion about classification of the 

Paleozoic pleurotomariaceans has ranged from the suggestion that no separate family is needed for the bulk
50 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

of Paleozoic genera (Dickens, 1963, p. 118) to a stout 

defense of the established classification (Batten, 1967, 

p. 262). Obviously, no classification can remain static 

as additional genera are added. Furthermore, opinions 

shift about the significance to be assigned to various 

features of morphology.

The principal area of contention is the Eotomariidae. 

This family was given the following diagnosis by 

Knight, Batten, and Yochelson (1960, p. 1202): "Shell 

turbiniform to trochiform; labral slit invariably 

present, generating concave selenizone bordered by 

threads at approximately mid-height of whorl." We are 

not convinced that the Eotomariidae constitutes a natural grouping. However, because the family includes 

genera that do not occur in the Carboniferous rocks 

that form the basis for our recent studies, our revisions 

of classification will be limited to lower taxonomic levels. This family name may be used for those gastropods 

that have a peripheral selenizone separating upper and 

basal whorl surfaces; only rarely is a short segment of 

outer whorl face present.

In the 1960 classification, subdivisions were based 

primarily on whorl shape. We now think it more reasonable to consider the form and size of the selenizone 

as at least as significant as whorl shape. Our treatment 

shows some inconsistency in that selenizone features 

that in our view distinguish higher taxa among the 

pleurotomariaceans are accorded less significance 

among the bellerophontaceans. However, the selenizone in bellerophontaceans is far less variable, and the 

number of genera and species far fewer than among the 

pleurotomariaceans, where the need for criteria to subdivide the superfamily is therefore much greater.

In 1938, Wenz divided the family Pleurotomariidae 

into 10 subfamilies, among which were Eotomariinae, 

Ptychomphalinae, and Ptychomphalininae. Knight, 

Batten, and Yochelson (1960, p. 1203,1204) raised the 

Eotomariinae to family rank and included it in three 

subfamilies, Eotomariinae, Agnesiinae, and Neilsoniinae. The Eotomariinae, being the most extensive, was 

divided into two tribes, Eotomariides and Ptychomphalides. As the result of various rearrangements and 

synonymies, Wenz's Ptychomphalinae and Ptychomphalininae were both included in the tribe Ptychomphalides by Knight, Batten, and Yochelson (1960). 

These changes in rank were perfectly legitimate, although somewhat confusing because family-group 

names based on Ptychomphalus Agassiz and Ptychomphalina Fischer are involved. In one partial revision, 

Sadlick and Neilson (1963, p. 1090) suggested that the 

Ptychomphalides be returned to subfamily rank to contain four Mesozoic genera referred to the tribe. 

Ptychomphalinae Wenz was thus restored and included 

under the Eotomariidae.

For the present, we continue to recognize the four 

subfamilies of the Eotomariidae, and we add a fifth. We 

are making minor modifications to Neilsoniinae and 

more extensive revision of Ptychomphalinae and Eotomariinae. This report is not concerned with any genera 

referable to Agnesiinae.

Subfamily PTYCHOMPHALINAE Wenz 

Tribe MOURLONIIDES Yochelson and Dutro

Diagnosis. Subglobose pleurotomariaceans having 

flat or gently convex peripheral selenizone.

Description. Shell moderately low-spired. Whorl 

cross section inflated, upper whorl surface distinctly 

arched; periphery at upper, middle, or lower edge of 

selenizone; base also well rounded and anomphalous to 

minutely phaneromphalous. Selenizone flat or close to 

curvature of whorl, flush or raised slightly, nearly parallel to axis of coiling in inclination. Ornamentation 

weak, having collabral elements predominant.

Discussion. Recognizing the need for at least one 

additional tribe within the subfamily, Yochelson and 

Dutro (1960, p. 136) inadvertently used the name 

Mourlonides for part of the group that Knight, Batten, 

and Yochelson (1960, p. 1202-1204) referred to 

Ptychomphalides. Yochelson and Dutro should have 

used Ptychomphalinides Wenz for the tribe name, because the oldest family-group name must be used, even 

if the name-bearer has been placed in subjective synonymy. In 1974, we examined key types in the British 

Museum (Natural History), London, and concluded 

that Mourlonia and Ptychomphalina were distinct genera, independently confirming the view of Dickens 

(1978). We regard them as belonging in different 

family-level taxa. We are retaining Mourloniides 

Yochelson and Dutro for one of these groups. If 

Ptychomphalinae is raised to its former subfamily 

rank, as seems to have been the intent of Sadlick and 

Nielsen (1963, p. 1090), it would include the tribes 

Mourloniides and Ptychomphalides, and we so subdivide it.

We continue to follow Knight, Batten, and Yochelson 

(1960, p. 1202-1203) in associating Taeniospira and 

Tropidostropha with Mourlonia, but this is purely a 

matter of convenience. We have no new information on 

either genus but believe that careful restudy might 

result in the transfer of one or both of these genera out 

of this tribe.

Genus MOURLONIA de Koninck, 1883

Diagnosis. Medium-sized to large subglobose 

pleurotomariaceans having generally smooth turbiform shape and bearing selenizone at periphery either 

conforming to curvature of shell or flat; either one or
SYSTEMATIC PALEONTOLOGY 51

both sides of selenizone may be slightly raised; either 

edge may be precisely at periphery. Shell ornamented 

by collabral and spiral lirae; spirals commonly subdued 

or absent.

Discussion. We examined the holotype and other 

specimens of the type species of this genus, Helix carinatus J. Sowerby, in the collection of the British Museum (Natural History), along with other material referred to various species of Mourlonia in the same 

collection. From this study followed our decision to recognize Ptychomphalina again as a distinct genus and to 

redefine Mourlonia . We believe that de Koninck (1883, 

p. 77-98), in his first interpretation of his genus, included too many species in Mourlonia (57 in all) and set 

the style for a rather loose treatment of the genus that 

has been evident ever since.

Dickens (1963, p. 118), in connection with the description of Permian species from Australia that he 

assigned to Mourlonia, considerably expanded the concept of this genus. He suggested that Platyteichum 

Campbell (1953) be reduced to subgeneric rank under 

Mourlonia; Knight, Batten, and Yochelson (1960, 

p. 1206) placed that genus in the Eotomariides. Dickens 

also proposed two new taxa as subgenera of Mourlonia, 

M. (Pseudobaylea) and M. (Woolnoughia). Through the 

kindness of Dr. Dickens, we had the opportunity of 

examining plaster casts of the type species of both subgenera.

Without elaborating reasons in detail, we would 

place Pseudobaylea near Glabrocingulum and would 

place Woolnoughia with more question near Worthenia. We agree with Dickens (1963) that Platyteichum is 

probably not very closely allied to Glabrocingulum. It 

is a fully distinct genus, allied to our new genus Deseretospira.

We would refer to other genera most of the American 

late Paleozoic species that nave been included in Mourlonia (Yochelson and Saunders, 1967, p. 129, 130; 

Thein and Nitecki, 1974, p. 83). We are transferring 

(1) Mourlonia angulata Easton and Mourlonia? reloba 

Yochelson and Dutro to Ptychomphalina ; (2) Pleurotomaria mississippiensis White and Whitfield and Mourlonia northviewensis S. Weller to Worthenia; and 

(3) Mourlonia solida Hyde to Spiroscala.

"Mourlonia" textus Hyde may not even be a pleurotomariacean; the drawing that supposedly shows a selenizone (Hyde, 1953, pi. 46, fig. 5) is not convincing. 

The specimen certainly is not a Mourlonia] pending 

restudy, we are unable to reassign the species. Mourlonia? cancellata Chronic is known only from the upper 

whorl surface. Until more morphologic information is 

available, its generic status must remain in doubt.

American Mississippian species of Mourlonia. 

iowensis (Worthen), 1890 (Pleurotomaria)

kentuckiensis (Thein and Nitecki), 1975 (Trepospira [Angyomphalus]} 

textiligera (Meek), 1872 (Pleurotomaria) 

venusta n. sp.

We examined a plaster cast of Pleurotomaria iowensis Worthen from the Keokuk Limestone of Iowa. This 

poorly known species might be a Mourlonia, and we 

hereby transfer it to that genus. The species is large 

and subglobose, but no distinguishing features are preserved on the type. Until this speies is better established, we would restrict the name to the type lot.

Pleurotomaria textiligera Meek, from the Waverly 

Group at Medina, Ohio, has a shell similar in shape to 

that of Mourlonia. Although we did not see the holotype or topotypes of this species, we examined a lot of 

nine specimens in the USGS collection, collected by 

Girty from the upper Sharpsville Sandstone on the 

Black River, near Homerville, Medina County, about 

20 miles (32 km) southwest of the type locality. One of 

these specimens is almost identical in size, shape, and 

sculptural details with that shown in Meek's original 

figure. We unhesitatingly assign this lot to Mourlonia 

and, on the basis of this information, herein transfer 

Meek's species to that genus.

Several unnamed species, described or mentioned in 

the literature, apparently belong in Mourlonia . One of 

them was described and figured by Thein and Nitecki 

(1974, p. 84,85, fig. 29) as Mourlonia sp. indet. from the 

lower point of the Golconda Limestone of Illinois. In our 

opinion, it is correctly referred to this genus.

Two specimens were described as Bembexia sp. by 

Girty (1915b, p. 37) in his paper on the fauna of the 

"so-called Boone Chert" of Arkansas (now regarded as 

a weathered zone in the Spring Creek Member of the 

Moorefield Formation). One is a Mourlonia, a crushed 

shell (USNM 168478), probably subglobose originally, 

bearing a slightly raised flat selenizone bordered at 

either side by a thread along a slight angulation; 

rather fine parabolic lunulae mark this selenizone; 

growth lirae are fine on the base and are coarser but 

separated by wide interspaces above the selenizone. 

The other specimen is a large steinkern, unrecognizable as to genus; the possibility exists, however, that it 

might represent the same species.

Girty had intended to use the name Bembexia magna 

for an undescribed species of Mourlonia from northeastern Oklahoma. However, his provisional use of this 

name for a fragmental specimen from the "Middle 

Boone Limestone" (a unit of Warsaw age within the 

Boone Formation) from the Batesville District, Ark. 

(Girty, 1929a, p. 94), which he thought might be the 

same species, irrevocably attached the name Bembexia 

magna to a poorly preserved Ptychomphalina.
52 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

We also tentatively transfer Trepospira (Angyomphalus) kentuckiensis Thein and Nitecki to Mourlonia. Certainly that species is not a Trepospira, and its 

shape and the configuration of its selenizone, as illustrated by Thein and Nitecki, suggest Mourlonia.

Mourlonia venusta n. sp.

Plate 4, figures 28-30

Diagnosis. Globose pleurotomariaceans bearing 

reticulate ornamentation in early and middle growth 

stages but becoming nearly smooth at maturity.

Description. Nucleus not known in detail, probably 

orthostrophic. Upper whorl surface of early whorls well 

rounded and ornamented by obscure growth lines. 

Shell expanding more rapidly after earliest growth 

stages, coordinate with development of spiral ornament; pleural angle nearly 100°; body whorl embracing 

penultimate whorl at middle of selenizone. Sutures 

faint, not impressed. Whorl profile consisting of three 

segments of different curvature: upper segment extending from suture to upper edge of selenizone and 

essentially following gentle arc so that shell extends 

farther laterally than downward; second segment limited to selenizone, more rounded than whorl segment 

above and having slight change in slope at its upper 

edge and an even fainter change at its lower edge, 

which also forms periphery; third and basal segment 

from lower edge of selenizone to columellar area, consisting of well-rounded curve following arc of circle of 

smaller diameter than that of upper whorl surface. 

Base marked by tiny umbilical chink, partly covered by 

slight reflexion of inner lip. Slip depth unknown. Selenizone broad, convex, not bordered, and flush except 

at most mature stage, where it is slightly depressed; 

lunulae closely spaced but not prominent, U-shaped 

and very deep.

Growth lines proscline and straight from suture at 

angle of approximately 15° from vertical for about 

three-fourths of width of upper whorl surface, then 

gradually curving more strongly prosocline and just 

before reaching selenizone, sweeping backward; below 

selenizone, strongly forward opisthocline for short distance downslope, curving increasingly toward orthocline to columellar area. Ornamentation changing 

markedly with growth stages; on upper whorl surface, 

early stages ornamented by low, closely spaced relatively prominent growth lirae, having interspaces 

about twice width of lirae; later stage ornmented by 

growth lines and approximately four prominent spiral 

lirae, forming reticulate pattern with growth lirae; 

number of spiral lirae gradually increasing to about 10 

and becoming predominant; with increasing maturity, 

spiral lirae gradually disappearing, those near suture

persisting longest, concomitant with decrease in prominence of growth lirae; at maturity, shell is nearly 

smooth; ornament of basal surface comparable with 

that of upper surface, except finer; threads of both surfaces somewhat irregular in course.

Dimensions. Holotype measures 15.5 mm in height 

and 17.2 mm in maximum width.

Discussion. This species was found associated with 

Lunulazona nodimarginata (McChesney) in the upper 

part of the Goniatites americanus Zone in the Granite 

Mountain section.

Mourlonia venusta is distinguished from most other 

mourlonias by the well-developed spiral lirae on the 

early whorls. Mourlonia textiligera (Meek) also has 

well-developed spiral lirae throughout growth but differs in being higher than wide and in having a nearly 

flat sloping upper whorl surface, giving the spire a 

broadly conical appearance. Spiral sculpture also is 

present on the type species of the genus Mourlonia carinata (J. Sowerby) but is subordinate to the collabral 

ornament and lacking on many species. M. venusta also 

is more globose than M. carinata, and its selenizone is 

flush with the whorl, rather than slightly raised as in 

M. carinata. No spiral lirae have been observed on any 

of the unnamed species cited above.

Type. Holotype USNM 210976; paratypes USNM 

210977.

Occurrence and number of specimens. USGS collections 17018-PC (8), 25558-PC (4), Juab County.

Tribe PTYCHOMPHALIDES Wenz

Discussion. Ptychomphalus is restricted to rocks of 

Mesozoic age. However, the name has been used for five 

Carboniferous species, which are reassigned herein. 

We assign Ptychomphalus laudenslageri Sayre, from 

the Upper Pennsylvanian Drum Limestone of Kansas, 

to Neilsonia because of its high spire, impressed selenizone, and characteristic ornamentation. The remaining 

four species were all described by Weller (1916) from 

one locality in the Ste. Genevieve Limestone (Upper 

Mississippian) in Illinois. Ptychomphalus sinuatus, the 

first of these, was transferred to Baylea by Thein and 

Nitecki (1974, p. 81); however, we believe that it is a 

tiny Glabrocingulum (Glabrocingulum) and herein 

transfer it to that genus. On the basis of our examination of topotypes, we transfer P. wortheni to Borestus, 

and P. ? fountainensis questionably to Yunnania. P. depressus is arbitrarily transferred with question to Portlockiella. This last species is inadequately illustrated 

and is not represented in the collections from the Ste. 

Genevieve Limestone that we examined. The tribe 

Ptychomphalides, as interpreted in this report, is thus 

not represented in American Carboniferous rocks.
SYSTEMATIC PALEONTOLOGY 53

Subfamily EOTOMARIINAE Wenz 

Tribe PTYCHOMPHALINIDES Wenz

Diagnosis. Globose pleurotomariaceans having 

raised peripheral concave selenizone, generally bordered by flanges.

Description. Shell expanding rapidly. Upper whorl 

surface inflated; lower whorl surface about same width 

as upper. Flanges normally raising selenizone distinctly above general curvature of whorl surface; selenizone itself concave, peripheral, having either upper 

or lower edge forming widest part of shell; flanges 

nearly equal in extension from whorl. Base anomphalous to minutely phaneromphalous. Ornamentation predominantly collabral.

Discussion. Defining the geometry of the selenizone is a complex issue and one that bears on the problem of distinguishing this tribe from the Mourlonides. 

In Mourlonia and allied taxa, the selenizone normally 

is flush with the whorl and is flat to slightly convex, 

though it may also be very slightly concave. In 

Ptychomphalina and its allies, the selenizone is always 

raised. In some forms, the selenizonal area is far extended from the general surface of the shell and is obviously flangelike. In Ptychomphalina, the selenizone is 

raised only a short distance above the general whorl 

surface, and in many species it is concave in profile 

between its upper and lower margins. One might argue 

that this form of selenizone is actually bordered by 

spiral lirae rather than being raised. However, we 

judge that lirae would be rounded and would have a 

convex profile on both their inner and outer faces. In 

contrast, the outer surface of a flange curves outward to 

nearly horizontal, relative to the axis of coiling, and the 

inner surface follows the curvature of the selenizone, 

which more commonly than not is concave.

The width of a selenizone may be significant in relation to the degree to which the selenizonal area is 

raised above the general shell surface. Perhaps a wide 

selenizone, as seen in Mourlonia, cannot be raised to 

any great extent, because it might form a zone of potential weakness. On the other hand, a narrow selenizone, 

as seen in Schwedigonia or Spiroscala, may be raised 

with less danger of weakening the shell. Possibly, a 

very narrow selenizone must be strongly flanged for 

strength, but this remains for future investigators to 

consider.

In addition to Ptychomphalina, we are assigning to 

this tribe Nodospira Yochelson and Dutro (1960), a 

genus that was not in the "Treatise on Invertebrate 

Paleontology" classification. Other genera may be included when the details of their selenizones are better 

known. Genera that have a very narrow, strongly

flanged selenizone may belong here or may constitute 

yet another group.

Bembexia, Clathrospira , and Eotomaria of the Eotomariides are similar to Ptychomphalina in having a 

flanged concave selenizone, as defined above. However, 

they are easily distinguished because the selenizone is 

distinctly inclined, the lower edge of which obviously 

forms the periphery. We examined topotype material of 

the type species of Bembexia and suggest that much 

American usage of this genus is incorrect; we do not 

regard any American Carboniferous species as properly referred to this genus.

Genus PTYCHOMPHALINA Fischer, 1885

Diagnosis. Subglobose pleurotomariaceans having 

a narrow raised concave selenizone, peripheral in position.

Description. Shell moderately low spired; whorl 

profile relatively simple, inflated. Upper whorl surface 

having approximately same gently convex curvature 

as basal surface. Selenizone narrow compared with 

height of whorl, concave between weak flanges bordered at either side by shallow groove. Base anomphalous to narrowly phaneromphalous. Collabral ornament predominant, prominent.

Discussion. This genus was placed in the synonymy of Mourlonia by Thomas (1939, p. 58). Knight 

(1944, p. 457) and Knight, Batten, and Yochelson 

(1960, p. 1203) followed this synonymy without any 

discussion. Data on Paleozoic pleurotomariaceans have 

increased markedly since 1960, and we now know considerably more about diversity at the generic level than 

was recognized previously. We agree with Dickens 

(1978) that Ptychomphalina is distinct from Mourlonia . This agreement is based on our independent comparison of the type material of the type species of Mourlonia and Ptychomphalina at the British Museum 

(Natural History).

Mourlonia has a relatively wide selenizone, whose 

outer surface has nearly the same curvature as the 

whorl; it may be flush with the whorl or slightly raised 

above the whorl surface at one or both margins. 

Ptychomphalina has a narrower, distinctly concave, 

and weakly to distinctly flanged selenizone. The two 

taxa were placed in synonymy because they both possess a peripheral selenizone and an inflated lower part 

of the shell. By emphasizing the character of the selenizone rather than the overall shape, we suggest that the 

seemingly close relationship of Ptychomphalina to 

Mourlonia is questionable.

Dickens (1957, p. 47) removed Ptychomphalina from 

synonymy with Mourlonia, placing emphasis on differences in ornament of the type species as they were
54 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

illustrated by Knight (1941, pi. 29). Dickens also suggested that variation in the character of the umbilicus 

that Thomas had used as one of the reasons to synonymize this name was not as significant as first 

judged. Knight, Batten, and Yochelson (1960) did not 

follow Dickens (1963, p. 118), who again emphasized 

the distinctiveness of Ptychomphalina from Mourlonia 

but did not elaborate upon his earlier discussion. However, Batten (1966, p. 26, 27) redescribed the type species of both Mourlonia and. Ptychomphalina, refiguring 

the type species of Ptychomphalina and placed them 

both in Mourlonia. In a short paper, Batten (1967, 

p. 262) took exception to Dickens' view; he emphasized 

the intergradation at the generic level between the 

type species of the two taxa in features of the umbilicus 

and whorl shape.

As for other related genera, the poorly known Permian genus Spiroraphella Grabau seems to have more 

in common with Ptychomphalina than with Mourlonia, 

but without authentic specimens at hand, we cannot be 

certain. In contrast, the Silurian genus Promourlonia 

Longstaff seems to agree with our concept of Mourlonia. The Silurian genus Eocryptaulina Foerste has a 

shape similar to that of Ptychomphalina, but the ornamentation is far more prominent.

American Mississippian species of Ptychomphalina. 

angulata (Easton), 1943 (Mourlonia)

burbankensis n. sp.

magna (Girty), 1927 (Bembexia)

The tiny specimen that Thein and Nitecki (1974, 

p. 83) described as Mourlonia angulata Easton, from 

the Glen Dean Limestone of Illinois, has a depressed 

selenizone and therefore probably does not belong to 

that species, nor to Ptychomphalina as here defined.

Bembexia magna Girty from the "Middle Boone 

Limestone" (of early Warsaw age) of the Batesville district, Arkansas, also belongs here. Girty (1929a, p. 94) 

described this species under the heading "Bembexia 

magna Girty, n. sp., MS?" Although he intended only 

provisional use of this manuscript name, he gave a 

short description of the rather poorly preserved and 

incomplete Arkansas shell, which is therefore the holotype of this species. We removed some of the matrix 

from this partly crushed specimen (USNM 166717) and 

found that it is a rather low-whorled shell having a 

raised concave peripheral selenizone bordered by 

threads; the principal ornament is of collabral lirae 

separated by wider interspaces.

In addition to the Mississippian species, Mourlonia? 

reloba Yochelson and Dutro from the Permian Siksikpuk Formation of Alaska, is another American form 

that has a raised concave selenizone; it is transferred 

herein to Ptychomphalina.

Ptychomphalina burbankensis n. sp.

Plate 3, figures 37-39

Diagnosis. Slightly inflated pleurotomariaceans 

having a moderately narrow concave peripheral selenizone and a nearly flat upper whorl surface.

Description. Shell low-spired, subglobose, expanding rapidly; pleural angle approximately 95°. Nucleus 

and early whorls unknown, holotype retaining about 

four whorls. Suture distinct; body whorl embracing 

previous whorl at or just below lower flange bordering 

selenizone. Profile of upper whorl surface simple, inclined outward and downward, very slightly convex 

from suture almost to lower edge, there curving horizontally to form an extremely narrow flange. Selenizone relatively narrow, concave between two low 

flanges, shallow, and slightly inclined, having lower 

flange at periphery. Whorl profile below lower flange 

curving downward and inward, forming distinct and 

uniform arch to columella, basal surface being much 

more inflated than upper whorl surface. Base anomphalous. Inner columellar lip straight, without inductura. Outer lip unknown; slit not visible but less than 

one-quarter whorl in depth.

Growth lines prosocline on upper whorl surface, 

forming an approximate 70° angle with suture, continuing straight for inner three-fourths of this surface, 

and then curving to meet upper flange at an approximate 60° angle; strongly opisthocline below lower 

flange, forming angle of 10°-15° with edge of flange, 

extending forward and slightly downward a short distance before bending abruptly downward, orthocline to 

steeply prosocline on base. Ornament poorly known, 

probably exclusively collabral; upper surface bearing 

fine lirae having interspaces about twice their width 

but becoming increasingly obscure with growth; ornament on upper flange more prominent than on surface 

above; lunulae obscure; basal surface having growth 

lines of varying prominence, some appearing lamellose, but no other ornament.

Dimensions. The holotype has a height of 17.2 mm 

and maximum width of 14.5 mm, but, if the shell were 

complete, these dimensions would be closer to 18 and 

16 mm, respectively.

Discussion. This species is based on specimens in 

two collections from a bed carrying the Lunulozona 

sadlicki assemblage within the Paracravenoceras barnettense Zone in the Burbank Hills measured section. 

The preservation is poor; even the best specimens in 

this assemblage are slightly cracked and expanded.

Ptychomphalina burbankensis is clearly distinguished from Mourlonia venusta n. sp., a species of similar shape and size, by its less inflated upper whorl 

surface, somewhat narrower selenizone, which is con-
SYSTEMATIC PALEONTOLOGY 55

cave in profile, and its lack of spiral lirae. Ptychomphalina angulata (Easton) from the Pitkin Limestone 

of Arkansas differs from P. burbankensis in having a 

somewhat narrower pleural angle, a slightly more inflated upper whorl surface, and more prominent collabral ornament. P. magna (Girty) from the Boone Formation of Arkansas has a more depressed whorl and a 

more shallowly concave selenizone set off by angulations from the whorl surface above and below, and more 

prominent collabral ornament.

Types. Holotype USNM 210978; paratypes USNM 

210979, 211058.

Occurrence and number of specimens. USGS collections 17201-PC (2), 25546-PC (12), Millard County.

Ptychomphalina sp.

Plate 4, figures 18-20

Mourlonia sp. Sadlick and Nielsen, 1963, p. 1102,

pi. 149, figs. 11-13.

Discussion. This unique specimen, 16 mm in maximum width, has a prominent raised narrow concave 

selenizone bordered at either side by a flange. Therefore, it does not belong in Mourlonia as defined in this 

paper. The selenizone is narrower and more extended 

than that of Ptychomphalina burkankensis n. sp., and 

the whorls are more depressed, but the resemblance to 

Ptychomphalina is striking, and we believe that it belongs in that genus. The pleural angle is 105°. The final 

whorl is biconvex and embraces the preceding whorl 

immediately below the selenizone. The upper whorl 

face is sigmoidal in outline, rather flat and narrowly 

ramplike near the suture, moderately convex just 

below it, and fairly flat or gently convex across midslope, then flaring out to form the upper surface of the 

upper flange of the selenizone. Below the selenizone, 

the whorl slopes strongly inward and is gently concave, 

then rounds into the base, which is gently convex, becoming almost flat in the columellar area. The upper 

and lower parts of the final whorl at either side of the 

selenizone are approximately equal in height.

Growth lines are approximately orthocline at the suture, though curving prosocline at an angle of approximately 25° to a plane through the vertical axis of the 

shell on much of the upper whorl slope; near the selenizone, they curve to about 45° in crossing the upper 

flange; they quickly curve to opisthocline over the selenizone and are at an angle of about 45° in that direction on the lower flange of the selenizone; they curve 

toward orthocline over the concave part below the selenizone, and, becoming orthocline at the point of greatest convexity on the base, they continue straight to the 

columellar area. Principal ornament is of raised lirae 

following the course of growth lines, separated by interspaces three to four times as wide; where these lirae 

cross the flanges bordering the selenizone, they give a 

minute beaded appearance. Lunulae not observed 

within the narrow selenizone. Shell consists of two layers; the outer layer is about one-third the thickness of 

the shell, but its ornament is far more prominent than 

that on the inner layer.

We know of no other American species that resembles this shell, with the possible exception of Mourlonia 

angulata Easton, as pointed out by Sadlick and Neilsen 

(1963, p. 1102). We place that species also in Ptychomphalina. It has a more rounded periphery and a depressed selenizone, without the prominent flanges of 

the Utah species.

Ptychomphalina sp. is known only from one specimen 

collected along with the type lot ofLunulazona sadlicki 

n. sp. from limestone deposited in a euxinic facies of the 

Chainman Shale about 400 feet (122 m) above the top 

of the Joana Limestone. It was found in the Leppy 

Range, near Wendover, Nev. Even though this species 

does not occur within the area of our study, it was 

included by Sadlick and Neilsen (1963) as part of the 

Chainman gastropod fauna.

Figured specimen. USNM 134170.

Occurrence. Sadlick and Neisen locality 7-1, 0.3 

mile (0.48 km) N. 55° E. from Leppy Peak, about 3.5 

miles (5.6 km) north of Wendover, Nev., approximately 

in SW 1/4 SE 1/4 sec. 28, T. 34 N., R. 70 E., Elko 

County.

Tribe DESERETOSPIRIDES, new tribe

Diagnosis. Bluntly conical pleurotomariaceans 

having depressed concave peripheral selenizone between two raised flangelike borders. Shell trochiform; 

spire medium in height to moderately high spired. 

Upper whorl surface gently convex, nearly flat; outer 

whorl face composed of selenizone, only; base slightly 

flattened. Selenizone prominent, moderately broad, 

concave between bordering flanges. Ornament of spiral 

lirae, generally few and varying in number on upper 

surface; more numerous and consistent in number on 

basal surface.

Discussion. Within the Eotomariinae, a grouping 

of genera that have a concave selenizone, no place is 

currently available to accommodate those forms in 

which the peripheral selenizone is essentially vertical 

but distinctly concave between an upper and lower 

flange. Therefore, we are proposing here a new tribe 

based upon our new genus Deseretospira. So far as we 

can determine, this tribe occurs only in the late Paleozoic; however, we have not investigated Devonian or 

Triassic genera in detail and do not know whether the 

range of this tribe includes those systems.
56 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

In addition to the type genus, we include Wellergyi 

Thein and Nitecki (1974, p. 96), from the Upper Mississippian and Pennsylvanian of the United States. We 

have examined specimens from Monroe County, 111., of 

W. chesterensis Thein and Nitecki, the type species of 

this genus. These specimens, like the type lot, are less 

well preserved than the material upon which Deseretospira is based; therefore, we prefer to use the Chainman Shale material as the source of the name of the 

tribe.

Platyteichum Campbell from the Permian of Australia also fits into this tribe. It is somewhat higher 

spired than the type genus, has more numerous spiral 

lirae on the upper whorl surface, and does not seem to 

have collabral ornament. In spite of the considerable 

difference in time and distance between Platyteichum 

and the other two genera, the relationship appears to 

us to be very close. Deseretospira is intermediate in size 

between the tiny Wellergyi and the moderately large 

Platyteichum.

Genus Deseretospira n. gen.

Type species. Deseretospira monilifera n. sp.

Diagnosis. Bluntly conical pleurotomariaceans 

having flanged selenizone on periphery and numerous 

flat, shallowly stepped spiral lirae on base. Upper 

whorl surface essentially straight in profile throughout 

most of its length; earlier growth stages inclined more 

toward horizontal than later stages. Outer whorl face 

composed entirely of concave selenizone, bordered by 

distinct flanges above and below, and protruding from 

general whorl profile. Base flattened, covered by about 

a dozen flattish spiral lirae.

Discussion. Deseretospira is a distinctive shell, 

richly ornamented and showing moderate ontogenetic 

change, which gives it a shape slightly reminiscent of 

a beehive. It is known only from the type species. When 

additional species are found, we suggest that details of 

ornament, such as number and spacing of spiral lirae, 

be used to differentiate the taxa at this lower level.

Wellergyi Thein and Nitecki has a smaller, highspired shell than Deseretospira and does not show pronounced ontogenetic change; it also has few spiral 

lirae, especially on the basal surface. In spite of general 

similarity in size and shape, differentiation ofNeilsonia from Wellergyi is easy. The selenizone in Neilsonia 

is wider than that in Wellergyi, but is flat and bordered 

by lirae; in Neilsonia, an additional short segment of 

outer whorl face is present below the selenizone. 

Deseretospira differs from Platyteichum by its lower 

spire, less inflated base, and distinct reticulate pattern 

on the upper whorl surface formed by the intersection 

of the spiral lirae with collabral threads; Platyteichum

lacks collabral ornament and also is narrowly 

phaneromphalous.

Deseretospira is homeomorphic with Dictyotomaria 

Knight; in size, shape, and in most details of ornament, 

the resemblance is remarkable. However, in Dictyomaria, the selenizone is flat and sunk below the level 

of the outer whorl face; that characteristic allies the 

genus to Borestus. The selenizone in Deseretospira is 

distinctly raised from the general whorl surface by 

flanges at either side and is concave between them.

Phymatopleura Girty is as elaborately ornamented 

as Deseretospira, though somewhat higher and more 

conical. The broad flat selenizone of Phymatopleura is 

readily distinguished from the flange groove of Deseretospira. A review of the North American species of Phymatopleura suggests that the genus was interpreted by 

many workers in a relatively broad sense and that several of the Pennsylvanian species now included in it are 

not correctly placed.

Rhineoderma has an ornament like that of Deseretospira, but the beaded texture of the upper whorl surface is even more pronounced. Rhineoderma is low 

spired and more globose than Deseretospira, and the 

slightly sunken selenizone low on the whorl readily 

distinguishes it from Deseretospira. Almost certainly, 

Rhineoderma does not belong in the Sinuopeidae; 

placement in another pleurotomariacean subfamily is 

warranted. The generic name has been used in a somewhat different sense in North America from that in 

Europe. It has also been used, we believe incorrectly, 

for low-spired species having more incised whorls and 

prominent spiral ornament. Rhineoderma dinglense 

(Girty) from the so-called Brazer Limestone of Idaho 

andR.piasaense (Hall) from the St. Louis Limestone of 

Illinois are representative of this group. Although their 

ornament and shape are unlike those of Deseretopsira, 

their selenizones are similar to that of our new genus. 

Perhaps another new genus within the Deseretospirides should be named to accommodate these lowspired species.

Deseretospira monilifera n. sp.

Plate 7, figures 9-15

Diagnosis. Bluntly conical Deseretospirides having 

five beaded spiral lirae on upper whorl surface and 

about a dozen inclined gently stepped lirae on base.

Description. Nucleus unknown; early whorls having upper whorl surface less inclined than that in more 

mature stages, so profile is bluntly conical; pleural angle approximately 95°. Body whorl embracing penultimate whorl at lower edge of selenizone; suture obscure. 

Upper whorl surface gently inclined and inflated on 

early whorls; details of ornament unknown; mature
SYSTEMATIC PALEONTOLOGY 57

upper whorl surface beginning at flat, nearly horizontal sutural ramp, having main part of surface inclined 

45° from axis of coiling and straight in profile except for 

interruptions by spiral lirae; outer part curving concavely to form short, prominent, nearly horizontal 

flange. Selenizone shallowly concave between bordering flanges; upper flange forming periphery; lower 

flange gently inflated, inclined at about 45° for short 

distance, then bending abruptly inward at first spiral 

lirae and at successive lirae progressively increasing 

inclination toward horizontal, so that general aspect is 

of shell having nearly flat base. Base cryptomphalous; 

innermost part inclined very slightly upward adjacent 

to columella.

Growth lines orthocline on ramp, bending to prosocline, about 30° from vertical with little change of inclination until just before flange, where they curve to 

meet edge of flange at 45°; lunulae wide, shallowly 

U-shaped; growth lines steeply opisthocline on lower 

edge of flange, almost immediately curving to orthocline and then steeply prosocline before crossing 

first spiral lira; nearly straight on main part of base 

and inclined about 30° to edge of lower flange, but 

gently curved to form shallow sinus, concave adaperturally. Five spiral cords ornamenting upper whorl 

surface, nearly uniformly spaced between suture and 

flange, progressively finer toward flange; upper two 

lirae coarsely beaded, middle lira finely beaded; spiral 

lirae crossed by finer collabral threads, forming an 

elongate rectangular pattern; interspaces between collabral threads about five times width of threads; 

lunulae closely spaced, fine. Basal surface covered by 

11 to 13 fairly closely spaced, asymmetrically flattened 

coarse lirae, shallowly stepped, having at least relief on 

side toward columella, increasing in height toward columella. Shell substance of at least two layers, outer 

layer about one-third thickness of inner layer.

Dimensions. The holotype and figured paratype, 

respectively measure (in mm): height 11.8 and 14.6, 

maximum width 12.2 and 15.

Discussion. This species is based upon four specimens, all from the same locality, but from different 

collections. They came from a 20-foot (6.1-m) interval 

in the Jensen Wash section, Burbank Hills about 100 to 

120 feet (30.1-36.6 m) below the top of the 

Paracravenoceras barnettense Zone, in the lower middle 

part of the Chainman Shale. Deseretospira monilifera 

occurs with Glabrocingulum (Glabrocingulum) hosei n. 

sp. in a ratio of roughly 1 to 300 specimens and can be 

easily be overlooked because of similarity in its size 

and general appearance to G. (G.) hosei. It differs from 

G. (G.) hosei in its bluntly conical shape, shorter base, 

beading of the lirae, and position of the selenizone 

lower of the whorl.

Several species of Dictyotomaria and, to a lesser extent, Phymatopleura also are similar to Deseretospira 

monilifera in general shape and ornament. We would 

thus urge caution in attempting to identify species that 

do not preserve the selenizone, which is raised in 

Deseretopsira and depressed in the other two genera.

Types. Holotype USNM 210980, paratypes USNM 

210981-210983.

Occurrence and number of specimens. USGS collections 17187-PC (1), 22857-PC (1), 25262-PC (1), 

25264-PC (1), Millard County.

Tribe GLABROCINGULIDES, new tribe

Diagnosis. Turbiniform to trochiform pleurotomariaceans having moderately narrow peripheral selenizone at upper angulation; selenizone concave, bordered 

by projecting flanges and commonly tilted outward 

slightly; ornament of spiral and collabral lirae.

Description. Shell expanding rapidly; spire conical 

to gradate; upper whorl surface convex to concave. Selenizone narrow, shallowly concave; flanges raising it 

only slightly above general curvature of whorl surface; 

outer face including part of whorl below selenizone several times width of selenizone. Base shallowly inflated, 

anomphalous to minutely phaneromphalus, columellar 

lip commonly reflexed; outer lip having slit less than 

one-quarter whorl in depth. Spiral lirae generally 

present, strongest near suture and on base, crossed by 

collabral lirae that are strongest near suture on upper 

whorl surface.

Discussion. The tribe Eotomariides, as presently 

constituted (Knight, Batten, and Yochelson, 1960, 

p. 1204), ranges from Middle Ordovician through Permian; Eotomaria-like gastropods are now known in the 

late Early Ordovician. We recognize a close relationship between Eotomaria and Clathrospira of Ordovician to Silurian age and would restrict the tribe Eotomariides to pleurotomaricaceans of this type. The 

predominantly Devonian genus Bembexia is far closer 

to Mourlonia than to other genera; we base this opinion 

on examination of a topotype specimen and not on the 

common usage of Bembexia in the American literature. 

Platyteichum, we believe, is related to our new genus 

Deseretospira, for which we are erecting another tribe.

We believe that the two remaining genera formerly 

included in the Eotomariides, Glabrocingulum and 

Eirlysia, form a compact group characterized by a concave selenizone at the upper angulation. We regard 

these taxa as distinct enough to be removed from close 

association with the early Paleozoic genera. In the 

Pennsylvanian of North America, Glabrocingulum is 

the single most abundant gastropod genus.
58 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Genus GLABROCINGULUM Thomas, 1940

Glabrocingulum is the most abundant gastropod 

genus in the Chainman shale, accounting for more 

than half the gastropods collected. Seven named species are recognized, belonging in two subgenera. Three 

additional taxa are also described under open nomenclature; these may be valid species. All our specimens 

are referred to one or another of these 10 taxa, with the 

exception of a single poorly preserved specimen from 

the northern Needle Range (USGS collection 15161- 

PC), which we are able to identify only as Glabrocingulum? sp.

Subgenus G. (GLABROCINGULUM) Thomas, 1940

Diagnosis. Fairly short-spired trochiform pleurotomariaceans, having concave selenizone between bordering flanges at upper angulation of whorl; upper 

whorl face gently concave to flat, base rounded; succeeding whorls attaching immediately or a little below 

selenizone; inner lip recurved over narrow umbilicus; 

outer lip having deep slit.

Discussion. This subgenus differs from G. (Ananias) in its shorter and less gradate spire and generally 

sparser sculpture. Some species that we include in 

G. (Glabrocingulum) have extremely depressed spires; 

others are small, the shape and position of the selenizone being the unifying character. On typical shells 

from the Chainman Shale, the spire and base are about 

the same depth. The Utah specimens show considerable variety, and the species change relatively rapidly 

through time and make useful guide fossils. We recognize nine species within the formation.

American Mississippian species of Glabrocingulum 

(Glabrocingulum). 

binodosum Sadlick and Nielsen, 1963

chesterense (Thein and Nitecki), 1974 (Trepospira 

[Trepospira])

confusionense n. sp.

ellenae (Conkin), 1957 (Bembexia)

granulosum n. sp.

hosei n. sp.

inflatum Sadlick and Nielsen, 1963

mephitifontis n. sp.

minutum Rollins, 1975

quadrigatum Sadlick and Nielsen, 1963

sinuatum(S. Weller), 1916 (Ptychomphalus)

Stella (Winchell), 1862 [1863] (Pleurotomaria)

stellaeforme (Hyde), 1953 (Mourlonia?)

Trepospira (Trepospira) chesterensis Thein and 

Nitecki (1974, p. 79, figs. 25a-f) was based upon "one 

fairly good and three more or less fragmentary specimens" from two localities in the Golconda Limestone in 

southern Illinois. These specimens are clearly lowspired glabrocingulums. We have examined a lot of 

more than 500 specimens from a locality in the NE V4 

NE 1/4 sec. 26, T. 4 S., R. 9 W. in Monroe County, 111., 

collected by G. H. Girty and Stuart Weller in 1912. 

Many are abraded and have the selenizone worn down 

to a smooth raised band. Unabraded specimens have an 

ornament of fine collabral lirae crossed by spiral lirae, 

minutely nodose at the intersections, particularly near 

the suture; these shells all preserve a raised concave 

selenizone bordered by a lira at either side and tilted 

outward slightly.

Bembexia ellenae Conkin from the New Providence 

Shale of Kentucky is also hereby transferred to G. 

(Glabrocingulum). We examined the primary types 

(USNM 127325-127329) and find that this species differs from most other species of G. (Glabrocingulum) in 

its strong nodose spiral lirae of variable thickness and 

in its turbiform shape.

Ptychomphalus sinuatus S. Weller from the Ste. 

Genevieve Limestone in Illinois is a tiny species having 

the shape of G. (Glabrocingulum). We examined topotypes collected by Weller and Girty and here transfer it 

to G. (Glabrocingulum).

Pleurotomaria Stella Winchell from the Marshall 

Formation of Michigan likewise belongs in this subgenus, having much the same shape as G. (G.) grayvillense (Norwood and Pratten), according to unpublished 

notes of G. H. Girty, who examined Winchell's type 

material. G. (G.) stella differs from G. (G.) grayvillense 

in lacking spiral ornament and in lacking any sort of 

umbilical opening; in the Michigan species, this opening is covered by the reflexed apertural lip. Girty's unpublished figures of Winchell's holotype and a slightly 

larger specimen confirm that this is a tiny Glabrocingulum .

A similar species, described as Mourlonia? stellaeformis Hyde from the Byer Member of the Logan Formation of Ohio, was transferred to G. (Glabrocingulum) by Sadlick and Nielsen (1963, p. 1095).

Sadlick and Nielsen (1963, p. 1097, 1102) referred 

Baylea [Trepospira] inflata Elias (1958, pi. 1, figs. 8, 9) 

to G. (Glabrocingulum), and this species should be attributed to them. In his text, Elias (1958, p. 5-7) described this species as Baylea [Trepospira] stellaeformis (Hyde), and at the end of his description, he said 

that "It is identical with the Waverlyan species in all 

respects." The fact that he cited his figured specimens 

as "Baylea [Trepospira] inflata n. sp." in the plate description does not constitute the valid establishment of 

a new species according to Article 13 (a) of the International Code of Zoological Nomenclature (International 

Trust for Zoological Nomenclature, 1961, p. 13). It was 

not until Sadlick and Nielsen (1963, p. 1097) referred to 

Elias's description and illustrations and pointed out
SYSTEMATIC PALEONTOLOGY 59

differences between G. (G.) inflatum and G. (G.) stellaeforme (Hyde) that the Oklahoma species took on any 

validity. We therefore recognize this species as G. (G.) 

inflatum Sadlick and Nielsen.

Glabrocingulum (Glabrocingulum) granulosum n. sp.

Plate 6, figures 1^3, 12

Diagnosis. Glabrocingulums ornamented by alternating strong and weak spiral lirae, nodose at intersections of weaker collabral threads.

Description. Nucleus unknown; earliest known 

whorls orthostrophic, at least two of them unornamented and having a rather strongly inflated upper 

whorl surface; more mature whorls ornamented primarily by spiral lirae. Shell moderately high spired; 

pleural angle approximately 90°. Sutures distinct; body 

whorl embracing penultimate whorl distinctly below 

selenizone, though juncture seemingly is at lower 

flange in earlier stages. Mature whorl profile simple; 

upper whorl surface inclined uniformly outward and 

downward from suture to outer edge, where it flattens 

abruptly to form upper bordering flange of concave selenizone. Selenizone forming upper part of outer whorl 

face, moderately narrow, distinctly concave between 

narrow, relatively high, sharp bordering flanges, edges 

of which are almost vertical but having lower flange at 

periphery; below selenizone, outer whorl profile inclined steeply inward and downward, smoothly for 

about one-third of distance to columellar area, then 

curving gradually inward and following approximate 

arc of circle, so that basal whorl surface is poorly delineated from outer face. Base probably anomphalous, 

though a tiny umbilical chink may be present. Columellar lip not known in detail, but seemingly simple; 

depth of slit and other aperture details unknown.

Growth lines slightly curved, sweeping prosocline 

from suture and reaching selenizone at angle of about 

45°; steeply opisthocline immediately below selenizone 

but turning to orthocline at about one-sixth distance 

from selenizone to columella and continuing straight to 

columellar area, selenizone having well formed, closely 

spaced, fine lunulae. Upper whorl surface ornamented 

by spiral lirae, five being prominent on early whorls, 

and additional lirae intercalated on more mature 

whorls so that body whorl bears spiral lirae of two sizes; 

lirae bearing small nodes at each intersection with 

growth lirae, which are so closely spaced that interspaces are barely wider than nodes. Lower part of shell 

below selenizone ornamented similarly but with less 

obvious distinction between first- and second-order spiral lirae, of which about 15 are present on lower surface 

of body whorl; lirae on body whorl bearing fine interference nodes where crossed by growth lines.

Dimensions. The incomplete holotype, lacking approximately the last one-half whorl, measures 16.5 mm 

in height and 17.0 mm in maximum width.

Discussion. This species occurs at Granite Mountain, where it is sparse in most collections from the 

early Chesterian Goniatites granosus Zone. We also 

collected it in the same zone in the Pancake Range, 

White Pine County, Nev., about 1 mile (1.6 km) northnortheast of the ruins of Pogues Station.

G. (G. ) granulosum n. sp. seems to be most similar to 

G. (G.) ellenae (Conkin) from the New Providence 

Shale of Kentucky in having two sizes of nodose spiral 

lirae on the body whorl. The upper whorl surface in 

G. (G. ) ellenae is convex, bearing two or three prominent spiral lirae in the early whorls and six on the body 

whorl. In G. (G.) granulosum, the upper whorl surface 

slopes flatly, bearing five spiral lirae on the early 

whorls and 10 on the body whorl. On other species of 

G. (Glabrocingulum), such as G. (G.) confusionense n. 

sp. and G. (G.) quadrigatum Sadlick and Nielsen, that 

have several nodose spiral lirae on the upper whorl 

surface, these lirae grade downward in size from the 

suture to the selenizone.

Types. Holotype USNM 210984; paratypes USNM 

210985-210987.

Occurrence and number of specimens. USGS collections 17012-PC (7), 17015-PC (2), 17020-PC (2), Juab 

County; 20446-PC (1) Millard County.

Glabrocingulum (Glabrocingulum) mephitifontis n. sp.

Plate 6, figure 15; plate 7, figures 6-8

Diagnosis. Moderately small glabrocingulums 

having flat to slightly concave upper whorl surface ornamented by numerous fine collabral lirae, dying out 

toward selenizone, and crossed by a pair of subsutural 

spiral lirae; 9 or 10 fairly strong spiral cords on base.

Description. Shell trochiform; pleural angle approximately 70°. Nucleus unknown. Suture distinct, 

slightly impressed, joining previous whorl at upper 

edge of selenizone on early postnuclear whorls and 

moving rapidly downward with growth, so that within 

one volution, suture is below selenizone. Upper surface 

of early whorls gently concave from suture to outer 

edge, more mature stage having extremely narrow subsutural shelf followed by inclined surface showing essentially no curvature until just before selenizone, 

where surface flares almost horizontally to form prominent raised narrow flange. Selenizone relatively narrow, gently concave between two prominent flangelike 

lirae, inclined generally outward and down at angle of 

nearly 45° so that lower flange of selenizone forms periphery. Outer whorl face below selenizone very 

slightly concave in upper part, below which inclined
60 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

steeply downward and gently inward about 15° from 

vertical, followed by a shorter segment inclined about 

30° from vertical, rounding smoothly into base. Except 

for interruptions by spiral ornament, base forming arc 

of circle in profile, rounding into depression where it 

joins columella. Base anomphalous. Columellar lip 

short, without inductura; other details of aperture unknown.

Growth lines nearly orthocline from suture across 

narrow ramp, curving distinctly prosocline at its outer 

edge, and crossing upper whorl surface with slight curvature at about 45° to upper flange of selenizone; 

lunulae extremely obscure; growth lines strongly 

opisthocline immediately below lower flange for about 

half distance across outer whorl face, gradually curving to orthocline, and proceeding approximately 

straight to columella. Ornament on upper whorl surface of two spiral lirae, one at edge of ramp particularly 

prominent; rounded collabral lirae forming nodes on 

first two spiral lirae and having interspaces about 

twice as wide as lira, strongest between suture and 

upper spiral lira, much less prominent between the 

spiral lirae, and obscure below; outer whorl face having 

one obscure and two prominent spiral lira below selenizone; base ornamented by approximately nine more 

closely spaced and cordlike lirae.

Dimensions. Holotype, 9.3 mm in height and 

8.7 mm in width.

Discussion. G. (G .) mephitifontis n. sp., the 

Glabrocingulum of Skunk Spring, Confusion Range, is 

a rare species in the Chainman Shale, limited to the 

early Chesterian Goniatites granosus Zone. A small incomplete paratype was collected at Granite Mountain 

together with G. (G.) granulosum n. sp. Integradation 

between those two species is out of the question because 

they are two of the most unlike in the whole spectrum 

of Chainman Glabrocingulum species.

In having two spiral lirae near the summit of the 

upper whorl face, G. (G.) mephitifontis is like G. (G.) 

binodosum Sadlick and Nielsen, another Chainman 

species, but the latter form is much lower spired, wider 

than high, has a strongly oblique columella, and occurs 

much higher stratigraphically in the Chainman. 

G. (G.) inflatum Sadlick and Nielsen from the Redoak 

Hollow Member of the Goddard Shale of Oklahoma also 

is similar in having two spiral lirae, but the upper 

whorl surface is more concave, the collabral lirae 

weaker, and the outer face below the selenizone seems 

to be devoid of spiral lirae; the base is not known. The 

Oklahoma species also occurs higher stratigraphically, 

being late Chesterian in age.

Types. Holotype USNM 210988, paratype USNM 

210989.

Occurrence and number of specimens. USGS collections 17012-PC (1), 717037-PC (1), Juab County; 

15354-PC (1), Millard County.

Glabrocingulum (Glabrocingulum) confusionense n. sp.

Plate 5, figures 1-9; plate 6, figures 13, 14

Glabrocingulum quadrigatum Sadlick and Nielsen, 

1963 [part], p. 1098-1102, pi. 150, figs. 5-8 [not figs. 

1-4, 9-12].

Diagnosis. Glabrocingulums having selenizone at 

angulation slightly inclined at maturity; essentially 

flat and sloping upper whorl surface bearing three to 

five spiral lirae, the upper of which are nodose. Nucleus 

sunken.

Description. Shell moderately low, trochiform; 

pleural angle about 92°; suture distinct. Nucleus tiny, 

bulbous, of about 1 1/2 smooth whorls projecting above 

first postnuclear whorl, which commonly is partly 

sunken within second whorl. Rest of whorls show minor 

ontogenetic change, in early stages embracing near 

upper part of selenizone, so that sutural edge of upper 

whorl surface appears ramplike; with growth, point of 

juncture gradually moves to below selenizone; at maturity, upper edge of whorl appears as a coronate ridge. 

Upper whorl surface inclined outward and downward 

with essentially no inflation, flaring out abruptly to 

nearly horizontal on top of prominent flange. Selenizone narrow, gently concave between two sharp prominent bordering flanges, nearly vertical at earlier 

stages, but inclined about 15° from vertical at maturity, lower flange forming periphery. Outer whorl face 

and base not distinctly separable below flange; upper 

segment arbitrarily separated by spiral lirae, about 

twice width of other segments and inclined inward 

roughly 30° from vertical, followed by shorter segment 

of essentially same inclination and then a smooth wellrounded curve, approaching arc of circle. Base anomphalous but having shallow umbilical depression. Columellar lip thickened and reflexed, bearing an 

elongate excavation below umbilical depression. Slit 

depth less than one-quarter whorl; other details of 

aperture unknown.

Growth lines on upper whorl surface curving 

smoothly prosocline from suture to flange describing 

uniform gentle arc; lunulae faint, symmetrical, well 

formed, nearly semicircular and very closely spaced; 

below flange, growth lines opisthocline at approximately 45°, curving very rapidly to orthocline and, in 

early growth stages, proceeding straight to base; at 

more mature stages, swinging to form wide shallow 

sigmoidal curve occupying much of base. Ornament of 

upper surface composed most commonly of four spiral 

lirae, highest lira, adjacent to suture, cordlike, size of
SYSTEMATIC PALEONTOLOGY 61

lirae decreasing down whorl face, a thread common 

between lowest lira and flange. Flange four times as 

high as coarsest spiral lira. Collabral ornament finer 

than spiral lirae and separated by interspaces about 

four times as wide, becoming smaller toward flange. 

Intersection of spiral and collabral elements marked by 

nodes, extremely prominent near suture but decreasing in size downwhorl, minute and irregularly spaced 

on lowest spiral lira. Below selenizone and on base, 

about 16 lirae are present, the two highest lirae more 

widely spaced than any of others, those lower on whorl 

having interspaces about twice their width but those 

near columella more widely spaced and coarser; all 

these lirae are nodose, but nodosity is particularly 

prominent on lowermost ones.

Dimensions. The primary types are almost complete and undistorted, and the measurements give a 

reasonable idea of the original variation in shape. The 

first three types are from USGS collection 17187-PC; 

the last is from collection 23846-PC (measurements in 

mm):

USNM

Height --- 

Width ---- 

210995 211028 210994 210999

16.8

15.6

15.3

15.1

14.8

14.5

11.8

2 12.8

Discussion. G. (G.) confusionense n. sp. is one of 

two species included in the primary types of G. (G .) 

quadrigatum Sadlick and Nielsen (1963, p. 1098- 

1102). The holotype and five paratypes of G. (G.) 

quadrigatum came from Sadlick and Nielsen's locality 

2-1 in the Burbank Hills, which they recorded as 465 

feet (141.7 m) below the top of their uppermost member 

of the Chainman Shale. Another lot of three specimens 

collected by geologists of the California Oil Company in 

sec. 24, T. 15 S., R. 18 W., north of the Bishop Springs 

anticline in the Confusion Range was also included 

among the designated paratypes of G. quadrigatum ; in 

our opinion, these specimens belong in G. (G.) confusionensis despite strong similarities in ornamentation 

to G. (G.) quadrigatum. We are describing this new 

species from our own material from the Burbank Hills, 

but we refigure for comparison on plate 5, figures 4-6, 

the specimen from the Confusion Range illustrated by 

Sadlick and Nielsen (1963, pi. 150, figs. 5-8).

In the Burbank Hills, G. (G.) confusionense sp. 

occurs in approximately the upper 100 feet (30 ro) of the 

Paracravenoceras barnettense Zone, where it is, associated with G. (G.?) hosei n. sp. and the coleoid 

cephalopod Hematites barbarae Flower and Gordon.

'Columella arches.

G. (G.) quadrigatum, as restricted in this report, occurs higher stratigraphically most commonly in the 

upper part of the Cravenoceras hesperium Zone; in the 

Confusion Range it is fairly widespread in this ammonoid zone.

The two species are distinguished by their early 

whorls and ornament of the upper whorl surface. 

GAG.) confusionense has four, five, or three lirae on 

the upper whorl surface, in descending order of frequency among individuals; G. (G.) quadrigatum has 

five to nine lirae and threads on the mature upper 

whorl surface, most commonly six or seven. The nucleus of G. (G.) confusionense generally is set off by an 

abrupt widening of the first postnuclear whorl, the 

minute bulbous nucleus standing up like a tiny finial. 

In G. (G.) quadrigatum, the nucleus passes without 

significant change in coiling into the postnuclear 

whorls. Also, specimens of G. (G.) confusionense generally are a little larger than those of G. (G.) quadrigatum.

Young shells of G. (G.) granulosum, particularly 

those not well preserved, can be mistaken for G. (G.) 

confusionense, as they commonly have five lirae on the 

early whorls. However, G. (G.) granulosum generally 

has strong nodose lirae on the lower part of the upper 

whorl surface, and intercalated fine lirae commonly 

appear early in this species and contrast with the spiral 

lirae of G. (G.) confusionense, which decrease in size 

downslope and almost never are intercalated.

Type. Holotype USNM 210994; paratypes USNM 

134182-134184, 210995-210999, 21102, 364705, 

364706.

Occurrence and number of specimens. USGS collections 15165-PC (43), 15166-PC (1), 17055-PC (27), 

17186-PC (3), 17187-PC (55), 19603-PC (1), 20448- 

PC (8), 23846-PC (40), 25262-PC (87), 25557-PC (15), 

28611-PC (7), 28623-PC (14), Millard County.

Glabrocingulum (Glabrocingulum) quadrigatum 

Sadlick and Nielsen

Plate 5, figures 10-15; plate 6, figures 11, 16, 19 

Glabrocingulum quadrigatum Sadlick and Nielsen, 

1963 [part], p. 1098-1102, pi. 150, figs. 1-4, 9-12 

[not figs. 5-8].

Glabrocingulum (Galbrocingulum) quadrigatum. Gordon and Yochelson, 1983, p. 982-984, fig. 3CC. 

Diagnosis. Glabrocingulums having slightly inclined selenizone at maturity. Nucleus merging evenly 

with postnuclear whorls. Upper whorl surface bearing 

five to seven spiral lirae, upper lirae nodose.

Description. Shell of moderate height trochiform; 

pleural angle ranging from 75° to 91°, but 91° in holotype; suture distinct. Nucleus small, turbiform, 

smooth, of approximately 1 l/2 whorls, passing without 

obvious interruption into postnuclear whorls. Early
62 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

whorls embracing approximately at top of selenizone, 

but without appearing ramplike; point of juncture 

gradually moving to position below selenizone during 

growth, so that selenizone partly overhangs uppermost 

coronate spiral cord. Upper whorl surface having ramplike shelf on later whorls, but main part nearly flat, 

inclined outward and downward, and terminating in 

slight flare at upper flange of selenizone. Selenizone 

narrow, gently concave between two narrow prominent 

bordering flanges, vertical in early whorls, but inclined 

outward and downward at about 15° angle, so that 

lower flange is at periphery of shell. Below flange, 

outer whorl face flat to slightly concave, inclined downward and slightly inward, commonly separated from 

base by weak angulation. Base gently convex, anomphalous, but having shallow umbilical depression. Columellar lip thickened and reflexed, partly covering 

umbilical depression. Depth of slit not clearly shown, 

but growth lines indicate it approximates one-sixth 

whorl; other details of aperture not known.

Growth lines gently prosocline across upper whorl 

face, curving evenly from suture to flange, which they 

approach at approximate 30° angle; lunulae fine, faint, 

closely spaced, almost semicircular; below flange, 

growth lines are opisthocline, beginning at 45° to lower 

flange and curving to approximately orthocline as they 

cross subangulation between outer whorl face and 

base; on base, growth lines are gently curved sigmoidally, shallowly bowed adapically and then adaperturally toward columella.

Five fine spiral lirae normally appearing on first 

postnuclear whorl and continuing on to later whorls. 

Small nodes beginning on second postnuclear whorl at 

intersections of upper two spiral lirae and growth lirae, 

becoming much stronger on later whorls; other cords 

also bearing small nodes on later whorls. Outer face 

generally bearing one to five fine spiral lirae; 10 to 15 

stronger lirae ornamenting base, strongest at subangulation and becoming weaker toward columella, locally 

an occasional very fine intercalated thread. Interspaces 

between lirae several times wider than lirae.

Dimensions. Dimensions (in mm) of the holotype 

from Nevada (USNM 134176) are given below, but all 

the Nevada paratypes (USNM 134177-134181) lack 

part of the base. Measurements (in mm) of three hypotypes from Utah (USNM 211000-211002) are also 

given below:

USNM 134176 211000 211001 211002

Height ---- 

Width -----

6.4 

8.0

10.5

10.8

10.1

10.0

17.4

15.2

Discussion. The description of this species is based 

upon the holotype, paratypes from the type locality,

and better preserved supplementary specimens from 

the same 15-foot (4.6-m) stratigraphic zone at other 

localities in the Burbank Hills. As we pointed out in 

our discussion of G. (G.) confusionense n. sp., Sadlick 

and Nielsen (1963, p. 1098-1102) included two somewhat similar species in G. (G.) quadrigatum. These 

species came from beds roughly 500 feet (152 m) apart 

stratigraphically (in the Burbank Hills). Much of 

Sadlick and Nielsen's original description of G. (G.) 

quadrigatum, as well as the name they selected, is 

particularly applicable to the lower species. This species, for which we are proposing the name G. (G.) confusionense, is restricted to the Paracravenoceras barnettense ammonoid zone; it typically has four spiral 

lirae on the upper whorl surface. The holotype of 

G. (G.) quadrigatum, however, has six spiral lirae on 

that surface. It is a specimen of the stratigraphically 

higher species, which is restricted to the Cravenoceras 

hesperium ammonoid zone. This shell always has more 

than four spiral lirae ornamenting the upper whorl 

surface.

Our specimens show that G. (G.) quadrigatum has 

five to seven spiral lirae on the upper whorl surface; 

G. (G.) confusionense has three to five. A paratype of 

G.(G.) quadrigatum illustrated by Sadlick and 

Nielsen (1963, pi. 150, figs. 9-12) has five spiral lirae 

on the upper whorl surface. All the specimens from the 

type locality tend to be low spired and to have five or six 

lirae, but others from nearby localities within the same 

stratigraphic zone have five to seven lirae. Those having the greatest number of spiral lirae are generally 

higher spired. They are fairly common in the Foote 

Range and have six to seven lirae on the upper whorl 

surface; occasionally finer lirae are intercalated with 

coarser ones. A typical specimen bearing seven lirae is 

illustrated on plate 6, figure 11. In addition to the 

seven lirae on the upper whorl surface, the shell has 

two strong flanges bordering the selenizone, five fairly 

fine lirae on the outer whorl face, and 14 or 15 coarse 

lirae on the base; these lirae become finer toward the 

columella, but include two or three fine intercalated 

threads.

The nuclear whorls of G. (G.) quadrigatum pass 

without significant change in inclination into the early 

postnuclear whorls; this fracture also distinguishes 

G.(G.) quadrigatum from G. (G.) confusionense, in 

which the nucleus stands above the very low sloping 

first postnuclear whorl, which is shallowly immersed 

in the steepersloping second postnuclear whorl.

G. (G.) quadrigatum ranges rather widely through 

the Cravenoceras hesperium Zone and, so far as we 

have been able to determine, is restricted to that zone.

Types. Holotype USNM 134176; paratypes USNM 

134177-134181; hypotypes USNM 211000, 211001, 

211002.
SYSTEMATIC PALEONTOLOGY 63

Occurrence and number of specimens. USGS collections 17095-PC (13), 25249-PC (5), 25252-PC (2), 

Juab County; 717022-PC (7), 17023-PC (76), 

17056-PC (8), 17188-PC (12), 17209-PC (5), 

17219-PC (26), 17310-PC (52), 719604-PC (1), 

?20443-PC(3), 25274-PC (5), 25318-PC (9), 

25547-PC (21), 25550-PC (70), 25551-PC (11), Millard County.

Glabrocingulum (Glabrocingulum) binodosum Sadlick and Nielsen

Plate 5, figures 28-35; plate 6, figures 17, 18

Glabrocingulum binodosum Sadlick and Nielsen, 

1963, p. 1096-1098, pi. 149.

Discussion. To summarize the salient features of 

this species, G. (G.) binodosum has a low-spired shell, 

having a pleural angle of approximately 100°; the 

upper whorl face is gently convex. The selenizone is flat 

to gently concave, tilted at approximately 30° to the 

vertical axis of the shell, bordered by narrow shallow 

flanges. Below the selenizone, the outer whorl face 

commonly is shallowly concave and then curves convexly, before rounding into the base, which has a shallow umbilical depression partly covered by the reflexed 

inner lip. The outer lip is thin.

Our specimens show that G. (G.) binodosum commonly has two or three spiral lirae, or rarely four, just 

below the suture on the upper whorl face; the lirae 

farther from the suture are a little finer and more 

closely spaced. As many as three lirae may be conspicuously nodose (pi. 5, fig. 32-35). The nodes are closely 

spaced, occurring where growth lirae cross the spiral 

lirae. Lunulae are visible on some specimens, generally 

those having more prominent growth lirae. The base 

and adjacent part of the outer whorl face bear 10 to 16 

spiral lirae, finer toward the umbilicus, barely visible 

on some specimens, but commonly bearing tiny irregularly spaced nodes.

This species is distinguished from all other 

glabrocingulums in the Chainman Shale by its low 

spire, obtuse pleural angle, and gently convex upper 

whorl face. Its subdued spiral scupture, absent on the 

outer part of the upper whorl face and upper part of the 

outer whorl face, is also distinctive. G. (Ananias) 

seminudum n. sp. is closest in ornamentation to G. (G.) 

binodosum but has a higher stepped spire, more closely 

spaced spiral lirae on the upper whorl slope, lower 

pleural angle, and more prominent flanges and spiral 

cords on the base.

G. (G.) binodosum is not a common species and 

seems to be restricted to the upper part of the Chainman Shale. At its type locality in the Foote Range, this 

gastropod occurs 20 to 30 feet (6.1 to 9.1 m) above the 

Richardsonites merriami bed, or about 275 to 285 feet 

(84 to 87 m) below the top of the Chainman. From the

southern Burbank Hills, a single specimen was collected along with G. (G.) quadrigatum Sadlick and 

Nielsen and Cravenoceras hesperium Miller and Furnish from near the top of the C. hesperium Zone. 

Sadlick and Nielsen (1963, p. 1098) reported G. (G.) 

binodosum from the same area, 15 to 20 feet (4.6 to 

6.1 m) below the Chainman-Ely contact. These records 

indicate that it may range through the upper 500 feet 

(152 m) of the formation in this region.

Types . Holotype USNM 134172; paratypes USNM 

134173-134175; hypotypes USNM 211004, 211059.

Occurrence and number of specimens. USGS collections 14559-PC (1), 17310-PC (1), 22883-PC (19), Millard County.

Glabrocingulum (Glabrocingulum) sp. A

Plate 7, figure 21

Discussion. Another Glabrocingulum occurs in the 

Lunulazona nodimarginata assemblage in the upper 

part of the Goniatites americanus Zone in the Granite 

Mountain section. Most of the specimens are 

steinkerns, but remnants of the ornament are preserved on the figured specimen. These remnants of ornamentation, because of their low relief, are believed to 

represent the inner shell layer, the outer shell layer 

having been exfoliated. This specimen is turbiform, has 

slighly more than four whorls, and measures 10.5 mm 

in height and 11.0 mm in maximum width; the pleural 

angle is approximately 90°. The upper whorl surface is 

gently convex, sloping about 5° below horizontal at the 

suture, and flaring slightly at the selenizone, the lower 

edge of which forms the periphery. The selenizone is 

concave between two slightly projecting flanges. The 

base is well rounded, curving rather evenly downward 

and inward to a low point of greater convexity, then 

continuing upward and inward to the columellar areas. 

The inner lip is curved.

On the upper whorl surface near the aperture, eight 

poorly preserved spiral lirae are present, the outer two 

more closely spaced than the others; these lirae seem 

gradationally smaller outward from the suture. On the 

base, between the selenizone and the lowest point on 

the basal surface near the aperture, approximately 16 

poorly preserved lirae and finer threads are present, 

those nearest the selenizone alternating in strength. 

These lirae and threads are crossed by collabral 

threads that are nearly orthocline at the suture and 

curve to meet the upper edge of the selenizone at an 

angle of 45°. These collabral threads are obscure immediately below the selenizone, but over the first spiral 

ornament on the base, they are opisthocline. However, 

within a very short distance, the collabral threads 

curve to orthocline before they die out. At the intersections of the spiral and collabral threads, tiny nodes are
64 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

present. The lunulae have not been preserved, but the 

inner end of the slit indicates that they were shallowly 

U-shaped. The aperture is marked by a narrow groove 

that apparently represents a thickened cord just within 

the outer lip. The slit is well preserved, approximately 

one-fifth of a whorl in depth, and narrowly rounded at 

the inner end.

G. (G. ) sp. A, as perhaps might be expected, is closest 

to its stratigraphically near neighbor, G. (G.} granulesum n. sp. of the Goniatites granosus Zone. Both species have a roughly similar shape and have an ornament of numerous spiral lirae on both upper and lower 

whorl surfaces. G. (G.) granulosum differs in having a 

flatter sloping upper whorl surface, intercalation of 

narrow threads between wider lirae on this surface, 

and a more coarsely lirate base. G. (G.) sp. A has 16 

lirae on the base; specimens of G. (G.) granulosum of 

the same size have about 10.

The number of lirae on the upper whorl surface of G. 

(G.) sp. A also is similar to that of G. (G?) hosei n. sp. 

and G. (G.) quadrigatum Sadlick and Nielsen, middle 

and late Chesterian species, respectively, both of which 

may be distinguished by their more gently sloping 

whorls and finer lirae; G. (G.?) hosei differs in its general lack of collabral lirae and nodosity. G. (G.) mephitifontis n. sp., G. (G.) confusionensis n. sp., and G. (G.) 

binodosum Sadlick and Nielsen all have fewer lirae on 

the upper whorl surface than does G. (G.) sp. A. G. (G.) 

binodosum is lower spired than G. (G.) sp. A.

Figured specimen. USNM 211004.

Occurrence and number of specimens. USGS collections 17018-PC (8), 25558-PC (1), Juab County.

Glabrocingulum (Glabrocingulum) sp. B

Plate 7, figures 16, 17

Discussion. Another species of Glabrocingulum is 

represented by a few very poorly preserved specimens 

collected east of Coyote Pass in the Conger Range and 

associated with Richardsonites merriami (Youngquist) 

in a 6-inch (0.15-m) bed, approximately 400 feet 

(121.9 m) below the top of the Chainman Shale. Several 

specimens shown worn remnants of a concave selenizone, but only one preserves details of ornament. This 

specimen (pi. 7, figs. 16, 17) retains a row of relatively 

large nodes along a subsutural ramp, below which the 

upper whorl surface is strongly concave, flaring outward at its lower edge to form the upper flange of the 

selenizone. The selenizone is narrow, slightly raised, 

and concave between the two flanges. The lower whorl 

profile is narrowly horizontal on the underside of the 

lower flange, then bends abruptly downward and is 

rather evenly convex inward to the columella. The final 

whorl embraces the penultimate whorl just below the 

selenizone. Except for the subsutural nodes and their

downward prolongations, which are prosocline at an 

angle of about 65° to the horizontal, no collabral ornament is preserved on the upper whorl surface. One 

patch of worn shell on the final whorl shows three or 

four fine spiral lirae, widely spaced on the concave 

slope below the subsutural nodes. On the lower whorl 

surface, some coarser spiral lirae are preserved, crossed 

by collabral lirae that are approximately orthocline 

near the columella; their intersections appear nodose.

The aperture on the outer lip of this specimen is 

distorted by a calcite veinlet; allowing for the width of 

the veinlet, the shell measures 7.2 mm in height and 

6.8 mm in width.

This species is unlike any of the other Chainman 

species of Glabrocingulum in having a concave upperwhorl surface terminating above in a coronet. It occurs 

with G. (Ananias} seminudum and might possibly be 

merely an extreme variant of that species. A similar 

coronation is present below the suture on an undescribed species of Glabrocingulum from the upper part 

of the Pitkin Limestone in north-central Arkansas, but 

the degree of development of this feature varies considerably among individuals of the same population. The 

Arkansas material does not have the strongly concave 

upper-whorl profile of the Utah shell.

Figured specimen. USNM 211005.

Occurrence and number of specimens. USGS collection 22880-PC (8), Millard County.

Glabrocingulum (Glabrocingulum) sp. C

Plate 6, figure 21

Discussion. Yet another Chainman form of 

Glabrocingulum, is represented by a unique specimen 

collected by R. K. Hose from a 30-foot (10-m) interval in 

the Foote Ranch measured section, 160 to 190 feet (48.8 

to 57.9 m) stratigraphically above the Richardsonites 

merriami bed. This specimen is broken and could not be 

extracted from its hard limestone matrix, but the wellpreserved upper surface and part of the base of the final 

whorl are exposed. The upper whorl surface is very 

gently convex in profile and marked by many fine 

threadlike prosocline growth lines that begin at an angle of 65° to the suture and curve gradually back to 

meet the outer edge of this surface at an angle of approximately 30°. The growth lines are locally irregular 

in their orientation and tend to bunch and thicken subsuturally into closely spaced radially elongate nodosities, forming a slightly raised narrow band adjacent to 

the suture. No recognizable spiral ornament is present, 

but light reflected on this surface in some orientation 

seems to delineate faint microscopic spiral lines, about 

7 in the space of 1 mm. The base is imperforate but 

slightly depressed in the columellar area. It is ornamented by growth lines similar to those on the upper
SYSTEMATIC PALEONTOLOGY 65

surface. Although the shell is essentially smooth, the 

growth lines are thicker at intervals and form a faint 

collabral ornament. No well-developed spiral ornament 

occurs on the base, but the growth lines are faintly but 

regularly thickened at intervals to produce the effect of 

weak spiral sculpture. The specimen is 13 mm in width; 

the height cannot be measured because the apex is 

buried.

The absence of any clearcut spiral or collabral lirae 

ornamenting the surface of this species distinguishes it 

from all the other species in the Chainman Shale. It is 

closest to G. (Ananias) seminudum, which differs in 

having a gradate shell bearing two or three spiral lirae 

on the upper whorl face and base.

Figured specimen. USNM 211006.

Occurrence. USGS collection 15370-PC, Millard 

County.

Glabrocingulum (Glabrocingulum?) hosei n. sp.

Plate 5, figures 16-27; plate 6, figure 20

Diagnosis. Glabrocingulums having gradual 

downward shift of subsutural placement of whorls; ornament mainly of spiral lirae ranging from 8 to 11 on 

upper surface of body whorl.

Description. Shell trochiform; pleural angle approximately 88°. Sutures distinct, becoming impressed 

and prominent with increasing maturity. Shell showing ontogenetic change, each whorl embracing progressively lower on preceding whorl. Nucleus simple, orthostrophic, at least first two whorls lacking any 

ornament; coincident with appearance of ornament, 

whorl developing subsutural ramp, which disappears 

with increasing maturity; upper whorl surface simple 

below ramp or suture, inclined approximately 45° and 

not inflated, trending straight for its entire length except just before selenizone, where it flares abruptly to 

nearly horizontal, forming upper flange. Selenizone 

raised slightly between flanges, narrow, concave, but 

generally inclined outward at about 30° to vertical at 

maturity, lower flange forming periphery. Outer and 

basal whorl faces not clearly separate, arbitrarily divided on basis of prominence of spiral ornament. Outer 

whorl face below flange simple, inclined inward at 

about 30° from vertical, occupying segments approximately two-fifths of total height between lower flange 

and base of columella. Basal surface beginning with 

short segment inclined 45°, followed by series of segments between spiral lirae, each trending more toward 

horizontal than preceding segment, but still inclined 

about 20° above horizontal at lowest point. Base anomphalous, but showing narrow umbilical chink behind 

slightly reflexed columellar lip; inductura lacking; 

basal lip simple; slit in outer lip about one-fifth of 

whorl in depth.

Growth lines on upper surface prosocline, at angle of 

about 45° to suture, sweeping gently back toward 

flange and meeting it at angle of 30°, most of curvature 

in outer quarter of upper whorl surface; lunulae in selenizone symmetrical, closely spaced, obscure; growth 

lines below selenizone trending steeply opisthocline at 

45° to edge of flange, curving rapidly to orthocline, and 

continuing to steeply prosocline, about 15° from vertical and trending straight across base to columella. Ornament primarily of spiral lirae on upper and basal 

surfaces, some lirae being somewhat nodose or subcontinuous; mature upper whorl surface having prominent 

coarse lira adjacent to suture, which on earlier whorls 

is on edge of ramp; a second lira lies just below, separated by interspace about twice as wide as lira; a third 

smaller lira occurring about the same distance below 

second; between these three lirae and selenizone are 

five to eight spiral threads, the number remaining 

more or less constant in individual specimens but spacing increasing with maturity; spiral lirae intersected 

by fine growth lines that form prominent minutely 

nodose pattern on upper three lirae and some fine 

nodes at intersection with spiral threads. Outer whorl 

face having one weak lira at juncture with base and 

three to four threads above and below. Basal whorl 

surface bearing at least nine coarse spiral lirae, all 

minutely and closely noded, spaced on upper part of 

this surface so that interspaces equal width of two 

lirae, becoming gradually closer spaced toward columella.

Dimensions. Measurements (in mm) of holotype 

and two figured paratypes are as follows:

USNM 210990 210992 210991

Height 

Width

19.0

17.7

19.0

21.5

15.1

14.4

Discussion. This species is abundant at its type locality in the Burbank Hills measured section, particularly in a 20-foot (6.1-m) interval of soft brown shale 

and small calcareous nodules about 100 feet (30.1 m) 

below the lowest bed containing Cravenoceras hesperium Miller. In this interval, G. (G.?) hosei is the 

only Glabrocingulum, but immediately above, in the 

uppermost 100 feet (30.1 m) of the Paracravenoceras 

barnettense Zone, it is less common, its numbers being 

almost equal to those of G. (G.) confusionense n. sp. It 

ranges northward nearly to the northernmost Chainman Shale outcrops in the Confusion Range; in this 

area, it is even less common but again is found in numbers approximately equal to those of G. (G.) confusionense. G. (G.?) hosei was not found in the Granite 

Mountain or Skunk Spring sections, where the rocks of
66 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

this part of the formation consist of impure spiculitic 

limestone rather than soft shale. Its abundance at the 

type locality makes it by far the most common gastropod in the Chainman Shale in western Utah.

G. (G.?) hosei n. sp. is distinguished from the other 

named species in the Chainman Shale fauna by its 

subdued ornament of numerous fine spiral threads on 

the lower part of the upper whorl surface. In number of 

lirae on the upper whorl surface, it is most like G. (G.) 

granulosum n. sp., but the lirae are not intercalated or 

as generally nodose as in that species. In detail, the two 

uppermost lirae on this surface range from being interrupted and broken into elongate segments to nearly 

uniformly spaced nodes. The strong tendency for the 

spire of G. (G. ?) hosei to elongate in late maturity is not 

characteristic of most species of the subgenus; large 

specimens may superficially resemble G. (Ananias) in 

this tendency.

Types. Holotype USNM 210990; paratypes USNM 

210991-210993.

Occurrence and number of specimens. USGS collections 15165-PC (62), 15166-PC (8), 17055-PC (12), 

17187-PC (52), 17194-PC (226), 19602-PC (3), 

20448-PC (4), 22857-PC (1), 23846-PC (17), 

25262-PC (72), 25264-PC (540), 725284-PC (1), 

25557-PC (24), 28610-PC (75), 28611-PC (37), 

28623-PC (2), Millard County.

Subgenus G. (ANANIAS) Knight, 1945

Discussion. Two subgenera are recognized within 

the genus Glabrocingulum. Compared with Glabrocingulum (Glabrocingulum), which is distinguished by its 

more or less conical spire, the subgenus Glabrocingulum (Ananias) is far less common in Carboniferous 

rocks. This subgenus is characterized by its gradate 

spire, generally higher than that of the typical subgenus because each mature whorl meets the preceding 

one well below the selenizone. The ornament in G. 

(Ananias) seems to be relatively finer than that of G. 

(Glabrocingulum) and apparently does not develop the 

nodes at the intersection of spiral and collabral lirae 

that are present on many species of the typical subgenus.

We recognize two American Mississippian species 

that are referrable to G. (Ananias). One is Pleurotomaria nevadensis Walcott from beds of late Meramecian age in the Diamond Peak Formation. This species 

occurs near Eureka, Nev., associated with Lunulazona 

nodimarginata (McChesney) and Bellazona bella (Walcott), both of which are present in the Chainman Shale 

in Utah in the upper part of the Goniatites americanus 

Zone. We select as lectotype the specimen illustrated by 

Walcott (1884, p. 259, pi. 24, figs. 2, 2a) from the type 

lot of Pleurotomaria nevadensis. Walcott's types

(USNM 14413) are mostly exfoliated and appear to 

have been cracked out of limestone. The lectotype (pi. 7, 

figs. 31 33) is useful for comparison with our various 

Utah species of G. (Glabrocingulum). Although partly 

crushed and largely exfoliated, it retains a strip of shell 

running irregularly downward through several whorls; 

this strip preserves the ornament rather well. The most 

notable feature of the specimen is its large size. The 

lectotype is more than 3.5 cm high and superficially 

resembles a large Worthenia; five or six fine spiral lirae 

occur between the selenizone and the succeeding whorl. 

Another specimen, somewhat smaller, retains a patch 

of shell in the columellar area, which preserves what 

appears to be a narrow umbilical chink.

Nine paralectotypes are in the type lot. Two of these, 

however, one a broadly conical fragment of an immature shell, may not be conspecific. Five of the paralectotypes are larger than the average Chainman Shale 

specimen of typical G. (Glabrocingulum) but are 

smaller than the lectotype. One of them is an uncrushed steinkern, and three of the remaining four 

specimens retain some small amounts of shell; one 

small specimen retains much of its shell.

Two specimens of intermediate size in the type lot, 

which also retain most of their shell but which are not 

believed to belong in this species, we are leaving unassigned; possibly they represent two different genera. 

The two specimens from the Park City Formation that 

Girty (1910, p. 46, pi. 6, figs., 4, 5) tentatively assigned 

to this species are indeterminate steinkerns of pleurotomariacean gastropods.

The other species, G. (Ananias) seminudum Gordon 

and Yochelson, 1982, occurs in the Diamond Peak Formation of east-central Nevada and the Chainman 

Shale of Utah. The species is somewhat puzzling, as it 

combines the stepped whorls of G. (Ananias) with the 

sparser nodose spiral lirae of G. (Glabrocingulum).

Glabrocingulum (Ananias) seminudum Gordon and Yochelson

Plate 6, figures 4-10

^Glabrocingulum n. sp. aff. G. inflatum Sadlick and

Nielsen, 1963, p. 1102. 

Glabrocingulum (Ananias) seminudum Gordon and

Yochelson, 1983, p. 981-982, fig. 32BB, EE, FF.

Discussion. This species was described from 12 

specimens (USNM 211060-211062, 307482-307485) 

collected from the Diamond Peak Formation in eastcentral Nevada where it occurs with Cravenoceras hesperium Miller and Furnish. It has been identified in the 

Chainman Shale of Utah in a slightly higher stratigraphic zone. In the Burbank Hills, G. (Ananias) 

seminudum occurs in the upper part of the Chainman, 

associated with Rhipidomella nevadensis (Meek), esti-
SYSTEMATIC PALEONTOLOGY 67

mated at 200 to 300 feet (61 to 91 m) below the top of 

the formation. The Burbank Hills specimens are 

smaller than the Nevada ones and have finer spiral 

lirae. They may not be fully mature but have gradate 

larger whorls. One of them is figured on plate 6, figures 

4-7. For comparison, the holotype is refigured (pi. 6, 

figs. 8-10).

G. (A.) seminudum is easily distinguished from G. 

(A.) nevadense, the only other Mississippian species of 

the subgenus, by the sparser spiral lirae and coarser 

lirae on the base; most younger species of G. (Ananias) 

have fine crowded spiral lirae. G. (A.) seminudum is 

referred to Ananias because of its stepped mature 

whorls, but the spiral ornament closely resembles that 

of the typical subgenus G. (Glabrocingulum).

Two Chainman species of G. (Glabrocingulum) have 

similar ornamentation, G. (G.) binodosum Sadlick and 

Nielsen and G. (G.) mephitifontis n. sp. The first of 

these is easily distinguished from G. (A.) seminudum 

by its lower spire, wider pleural angle, lack of stepped 

whorls, relatively wider selenizone, and faint spiral ornament on the base. G. (G.) mephitifontis, in contrast, 

is similar to G. (A.) seminudum in having a narrow 

spire with a pleural angle of 70°, two spiral lirae on the 

upper whorl surface, and the final whorl meeting the 

preceding one below the selenizone in the middle of the 

outer whorl face. It is distinguished from G. (A.) 

seminudum by its whorls, which are not distinctly 

stepped, and the well-developed collabral lirae extending outward from the suture on the upper whorl surface, instead of only growth lirae as in G. (A.) 

seminudum.

Figured specimen. USNM 211063.

Occurrence and number of specimens (Chainman 

Shale). USGS collections 17059-PC (8), 717217-PC 

(2), 22880-PC (7), 25319-PC (11), 25548-PC (8), 

28612-PC (6), Millard County.

Subfamily NEILSONIINAE

Discussion. Typical Neilsonia Thomas has a peripheral selenizone that is raised and gently concave in 

profile, and fairly prominent collabral ornament. It is 

allied closely to the Permian genus Peruvispira 

Chronic, which differs primarily in having the body 

whorl embracing well below the selenizone and in being somewhat less prominently ornamented. Lunulazona is similar to those two genera but is somewhat 

lower spired, more prominently ornamented, and has a 

raised flattened selenizone.

If these three genera are considered representative of 

the subfamily, the remaining taxa currently placed in 

the same subfamily by Knight, Batten, and Yochelson 

(1960, p. I207) Pagodina Wanner, Apachella Winters, 

and Pareuryalox Haas differ markedly from them in

emphasizing spiral ornamentation at the expense of 

collabral features. Both Neilsonia and Peruvispira 

have an angulation some distance below the selenizone 

at the juncture of the outer and basal whorl faces, but 

this feature is related to shape rather than to ornament. Obviously, some further subdivision, or an alternative arrangement, is needed to recognize these distinctions. Pagodina, Apachella, and Pareuryalox are 

not within the scope of this paper, the first two being 

Permian in age and third Triassic. We therefore leave 

further consideration of this question to other workers. 

Sadlick and Nielsen (1963, p. 1090) compared 

Lunulazona with Nodospira, as well as with Neilsonia, 

and we concur with the differences that they cited. 

Nevertheless, although the subsutural nodes and collabral ornament of Nodospira show a vague similarity 

to those of Lunulazona, the two genera are probably no 

more closely related than at the family level. In this 

report, we are assigning Nodospira to the Ptychomphalinides of the Eotomariinae.

Genus NEILSONIA Thomas, 1940

Diagnosis. Moderately high-spired, tiny pleurotomariaceans, generally of four, rarely more, whorls, 

having a tiny row of nodes just below suture; two, or 

commonly three, keels ornamenting whorls. Selenizone 

low on outer whorl and just above suture on spire.

American Mississippian species of Neilsonia. 

insculpta (Hall), 1857 (Murchisonia) 

welleri Thein and Nitecki, 1974

Discussion. Murchisonia uninodocarinata Hyde 

was referred to Neilsonia by Thein and Nitecki (1974, 

p. 91). Its high spire of at least eight whorls and details 

of the sculpture, as illustrated by Hyde (1953, pi. 46, 

fig. 16), suggest a closer relationship to the Murchisoniidae than to the Neilsoniinae. We regard Pleurotomaria nodimarginata McChesney and Neilsonia? 

springeri Yochelson, both of which were included tentatively in Neilsonia at one time or another, as typical 

representatives of Lunulazona.

Easton (1942, pi. 11, fig. 5) figured a poorly preserved 

Neilsonia from the Pitkin Limestone of Arkansas.

Neilsonia sp.

Plate 7, figure 28

Discussion. This record is based upon five poorly 

preserved specimens from two localities, both in rocks 

of the Cravenoceras hesperium ammonoid zone. The 

three specimens from the Granite Mountain locality 

are coarsely silicified; the two specimens from the 

Foote Range locality are calcareous but partly 

limonitic, broken, and partly obscured by matrix. None 

of them shows growth lines. Nevertheless, the shape
68 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

and what remains of the ornament are similar enough 

to authentic specimens ofNeilsonia for us to have some 

confidence in the generic identification.

The most complete shell, of 3 l/z whorls, measures 

2.5 mm in length and 1.2 mm in width; the pleural 

angle approximates 45°; the overall appearance is steplike. The upper whorl surface is concave, curving from 

the suture downward and then gently outward to the 

outer edge, which is a fairly sharp angulation. The 

narrow area immediately below this, assumed to be the 

selenizone, is also concave between the upper 

bordering lira and an equally strong one beneath; this 

lower angulation is the periphery. The width of the 

presumed selenizone is about one-third that of the upper whorl surface. The basal angulation of the outer 

whorl face is a little less wide than the periphery, and 

the space between it and the edge of the selenizone is 

slightly narrower than the selenizone. The base is 

phaneromphalous, flattened, and inclined gently downward. The inner lip is vertical, and its lower tip seems 

slightly reflexed.

Gordon and Yochelson (1983, p. 984) described Neilsonia cf. N. welleri Thein and Nitecki from the same 

ammonoid zone in the Diamond Peak Formation of Nevada. The Nevada specimens are distinctly higher 

spired than this species, and the upper edge of the selenizone, not the lower, forms the periphery.

Figured specimen. USNM 348022.

Occurrence and number of specimens. USGS collections 25252-PC (3), Juab County; 25274-PC (2), Millard County.

Genus LUNULAZONA Sadlick and Nielsen, 1963

Diagnosis. Moderately high-spired pleurotomariaceans, rhomboidal in profile, having raised, slightly 

concave to flat peripheral selenizone; prominent collabral ornament.

Description. Upper surface nearly flat in profile; 

outer whorl face limited to raised selenizone; basal 

whorl surface slightly more inflated than upper one. 

Base anomphalous. Body whorl embracing penultimate whorl at lower edge of selenizone, which forms 

periphery; selenizone raised, flattened to very slightly 

concave. Ornament generally prominent, strongest on 

upper whorl surface, may include riblets and subsutural nodes.

Discussion. When first proposed, Lunulazona 

Sadlick and Nielsen (1963, p. 1089,1090) was assigned 

to the Eotomariinae, although assignment to the Neilsoniinae was considered by its authors. Because this 

genus is based on moderately high-spired shell, we 

herein assign it to the Neilsoniinae. Addition of other 

species to Lunulazona in the present report has somewhat broadened the concept of that taxon. Apparently 

it evolved as a separate stock, diverging from the 

Neilsonia-Peruvispira line in Late Mississippian time.

The generic description above is little changed from 

that of Sadlick and Nielsen, but we place more emphasis on the nature of the selenizone than on the ornament. Sadlick and Nielsen, for example, emphasized 

the lunulae on the selenizone as an important character. We find that the strength of the lunulae varies 

with the species and include some species that have 

relatively weak lunulae, such as Pleurotomaria nodomarginata McChesney.

In expanding our concept of Lunulazona, we are including species that have been referred to Mourlonia 

and Bembexia by previous authors. This decision raises 

the question of the differences between Lunulazona 

and these two genera.

In our view, Lunulazona includes subconical shells 

having a distinctly flat upper whorl profile, in contrast 

to Mourlonia, which includes subglobose shells having 

a distinctly convex upper whorl profile. Subsutural 

riblets or nodes are commonly present in Lunulazona 

but not in Mourlonia, which may have spiral lirae in 

addition to collabral lirae. Finally, the shells of Mourlonia are typically fairly large, whereas those of 

Lunulazona rarely exceed 15 mm in height.

Bembexia differs from both genera in having a concave selenizone between moderately strong threads; as 

we have said earlier in this paper, we do not regard this 

genus as occurring in Carboniferous rocks.

American Mississippian species of Lunulazona. 

costata Sadlick and Nielsen, 1963 

lativittata (Girty), 1910 (Bembexia) 

nodomarginata (McChesney), 1859 (Pleurotomaria)

?sablei (Yochelson and Dutro), 1963 (Mourlonia) 

[M. minuta Yochelson and Dutro, 1960, not 

Weller, 1915] 

sadlicki n. sp.

springeri (Yochelson), 1973 (Neilsonia ?) 

utahensis n. sp.

In addition to the type species, Lunulazona costata 

Sadlick and Nielsen from the Chainman Shale, and two 

other species described below from the same formation, 

we include in this genus Bembexia lativittata Girty 

from the Fayetteville Shale of Arkansas, which was 

placed in Mourlonia by Yochelson (1969a, p. 29); Bembexia nodomarginata (McChesney) from the Moorefield 

Shale of Arkansas, which was assigned to Neilsonia by 

Thein and Nitecki (1974, p. 91); Neilsonia? springeri 

Yochelson from the Crawfordsville Shale of Indiana; 

and, with question because of its wider selenizone and 

less rhomboidal shape, Mourlonia sablei Yochelson and 

Dutro from the Lisburne Group of Alaska.
SYSTEMATIC PALEONTOLOGY 69

In addition to the American species, we examined the 

type of Pleurotomaria lirata Phillips from the Dibunophyllum Zone in Yorkshire, England, in the collection of the British Museum (Natural History) and 

recognize this species as a typical Lunulazona. Less 

certainly, but probably also belonging in this genus is 

the holotype of Pleurotomaria undulata Phillips, in the 

same collection.

Lunulazona nodomarginata (McChesney)

Plate 4, figures 21-23

Pleurotomaria nodomarginata McChesney, 1859, p. 70;

1865, pi. 7, figs, la-c; 1868 [1867-1869], p. 47, pi. 7,

figs, la-c; Walcott, 1884, p. 259, pi. 18, fig. 15. 

Bembexia nodomarginata (McChesney). Girty, 1911,

p. 91, pi. 7, figs. 1-5; 1915b, p. 36, pi. 2, fig. 7;

Croneis, 1930, p. 54, pi. 13, fig. 17. 

Bembexia nodomarginata (McChesney). Snider, 1915,

p. 116. 

Neilsonia nodomarginata (McChesney). Thein and

Nitecki, 1974, p. 91.

Diagnosis. Moderately small turbiform pleurotomariaceans having raised, nearly flat selenizone; upper whorl slope ornamented by prosocline lirae thickening subsuturally to elongate nodes, alternating with 

shorter finer lirae.

Description. Shell inflated turbiform, pleural angle 

approximately 65°. Nucleus unknown; at least two 

early whorls having a smooth inflated upper whorl surface. Suture obscure; body whorl embracing penultimate whorl at lower edge of selenizone. Whorl profile 

undergoing minor ontogenetic change; mature upper 

whorl surface straight, not deviating essentially from 

inclination indicated by pleural angle, except just below suture where inclination is slightly shallower; profile of early whorls obviously composed of two segments 

of different inclination. Selenizone raised, slightly 

flanged and gently concave in early stages, gradually 

becoming flat and vertical or even inclined inward at 

maturity; periphery probably at upper edge of selenizone. Whorl profile below selenizone curving inward 

strongly and downward, flattening as it approaches columellar area. Base probably anomphalous.

Growth lines prosocline, at angle of about 70° to suture, straight across inner half of upper whorl surface, 

then curving to form approximate 45° angle with outer 

edge. Lunulae strongly arched, symmetrical, fine. Below selenizone, growth lines steeply opisthocline, forming approximately 75° angle with outer edge and continuing for short distance before bending orthocline 

and proceeding straight to columella. Ornament prominent in early growth stages consisting of raised collabral ridges thickening to subsutural nodes, becoming

very fine or dying out near selenizone, alternating with 

fine lirae that reach upward only to lower edge of 

nodose band; lirae on base moderately strong near selenizone, becoming finer toward columella.

Dimensions. The specimen figured from the Chainman Shale measures: height 6.8 mm, maximum width 

6.3 mm; Walcott's figured specimen seems proportionately wider, but the lower part of the shell is buried in 

matrix so the height cannot be measured accurately.

Discussion. The type lot of this species from the 

"Hamilton Group" near Batesville, Ark., was lost in the 

Chicago fire of 1871. However, McChesney's description is clear, and his illustrations are adequate enough 

to show that Pleurotomaria nodomarginata belongs in 

Lunulazona. Walcott (1884, p. 259) described this species from the Eureka District, Nev., from beds now 

known as the Diamond Peak Formation, of late Meramecian age. The specimens from the Chainman Shale 

of Utah in the Granite Mountain section occur in the 

upper part of the Goniatites americanus Zone, also of 

late Meramecian age.

The typical form of L. nodomarginata, according to 

McChesney's description, has the subsutural nodes alternating with finer lirae (McChesney called them 

striae). McChesney (1859, p. 70) said: "These [lirae], 

when seen through a lens, present somewhat the appearance of projecting lamellae. At the upper edge of 

the volution every alternate [lira] is elevated, forming 

a sort of elongate node, which are sometimes elevated 

so as to present the appearance of a band of nodes; the 

[lirae] between die out at the commencement of the 

nodes."

Girty (1911, p. 91, 92, pi. 7, figs. 1-4) repeated 

McChesney's original description and reproduced his 

illustrations. The specimen illustrated by Girty (1911, 

pi. 7, fig. 5) from Spring Creek, Ark., fits McChesney's 

concept of the species. Although partly decorticated, it 

retains details of the sculpture on the penultimate 

whorl, showing the alternating nodose and non-nodose 

lirae.

Other specimens referred to this species, which also 

came from Spring Creek, about 1 mile (1.6 km) above 

Ruddell's Mill, were illustrated later by Girty (1915b, 

p. 36, 37, pi. 2, fig. 7). These are silicified and have very 

prominent subsutural nodes but lack collabral lirae. 

We examined these specimens and believe that during 

the process of silicification these shells lost their outermost shell layer and therefore part of their ornament. 

We agree with Girty in referring them to L. nodomarginata.

We also examined material from other localities in 

the vicinity of Batesville, Ark., and from the Moorefield 

Formation about 3 3/4 miles (6 km) southeast of 

Chouteau, Mayes County, Okla. We found that two
70 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

undescribed species of pleurotomariaceans, similar in 

general shape and size to L. nodomarginata, occur with 

it at these localities. They bear a superficial resemblance to L. nodomarginata, and poorly preserved material might easily be confused with it. Both undescribed species lack subsutural nodes, and their 

collabral lirae reach from suture to selenizone, as well 

as occurring on the base. One taxon is slightly larger 

and more tumid than L. nodomarginata and has a 

slightly wider concave selenizone bordered by low 

flanges; we regard this species as belonging in 

Ptychomphalina. The other species is subconical and 

similar in shape to L. nodomarginata but has rather 

prominent subequal collabral lirae separated by fairly 

wide interspaces and bears a flanged selenizone. Its 

generic position, however, is less certain; in the two 

characters noted, it seems to be intermediate between 

Lunulazona and Ptychomphalina.

The Nevada specimens, described and figured by 

Walcott (1884, p. 259, pi. 18, fig. 15), agree with 

McChesney's description and illustrations. A photograph of the specimen from Diamond Peak Formation near Eureka (USNM 14414), which Walcott illustrated by a drawing, is shown in the current report on 

plate 4, figure 23. Walcott's specimens were collected 

by him in 1880 at the small conical hill at the western 

foot of Spring Mountain, east of Secret Canyon road, 

Eureka district, Nev.

Specimens from the Smithwick Shale in San Saba 

County, Tex., figured by Plummer and Moore (1921) as 

Bembexia nodimarginata, probably belong to a different genus. We examined part of Plummer and Moore's 

material in the U.S. Geological Survey collections and 

find that their shell is indeed subconical and ornamented by prominent collabral lirae; however, it is 

larger, lacks subsutural nodes on alternating lirae, and 

has an elevated concave selenizone bordered by a lira 

at either side. It seems to be congeneric with the second 

of two undescribed Arkansas-Oklahoma shells mentioned above.

This species differs from the type species of Lunulazona, L. costata Sadlick and Nielsen, in having welldeveloped subsutural nodes, much finer lirae on the 

upper whorl surface, particularly near the selenizone, 

and very fine subdued lunulae.

Figured specimen. USNM 211007.

Occurrence and number of specimens. USGS collections 17018-PC (19), 25558-PC (2), Juab County.

Lunulazona costata Sadlick and Nielsen

Plate 4, figures 31-33, 36

Lunulazona costata Sadlick and Nielsen, 1963, 

p. 1091-1093, pi. 148, figs. 1-11, text-figs. 2-5.

Discussion. The excellent description and illustrations of this species given by its authors are readily 

available and need not be repeated here. We have included several illustrations of specimens to supplement 

those given in the original publication. After examining several dozen specimens from the Chainman Shale, 

we need only make minor comments. First, the prominent lunulae on the selenizone are a constant feature of 

ornamentation, as was indicated by the authors. Second, the selenizone apparently is never convex but may 

be almost flat; slight concavity is the characteristic 

condition. Third, the ornamentation, especially on the 

upper-whorl surface, is variable; it consists mainly of 

collabral riblets, somewhat nodelike near the suture, 

some splitting into two below the nodes, alternating 

with finer threads, most of them intercalated between 

the riblets and not reaching the suture; on the lower 

whorl, these riblets are reduced in strength and are 

indistinguishable from growth lirae. Fourth, a considerable number of our specimens show evidence of 

shell breakage and rehealing during life. In other facies, species of Glabrocingulum that have a comparable size and shell thickness show a lower incidence of 

breakage. Species of Lunulazona from other parts of 

the Chainman Shale also show a lower incidence of 

shell breakage. We are unable to provide any definite 

reason for the phenomenon.

This species is relatively common in the Goniatites 

granosus Zone at Granite Mountain and is rare elsewhere. We found examples as far south in the Confusion Range as 4 miles (6.4 km) south of Skunk Spring.

Figured specimens. USNM 211007, 211008.

Occurrence and number of specimens. USGS collections 17012-PC (101), 17015-PC (47), 17020-PC (16), 

Juab County; 14553-PC (1), 20446-PC (2), Millard 

County.

Lunulazona sadlicki n. sp.

Plate 4, figures 24, 25, 34, 35

Lunulazona sp. A. Sadlick and Nielsen, 1963, p. 1093, 

1094, pl.148, figs. 12, 13; pi. 150, fig. 13. 

Diagnosis. Rhomboidal pleurotomariaceans having moderately broad selenizone only slightly raised 

but covered with prominent chevronlike lunulae.

Description. Shell moderately high spired, pleural 

angle approximately 75°; outline nearly diamond 

shaped. Nucleus and early whorl unknown. Body whorl 

embracing penultimate whorl at lower edge of selenizone. Whorl profile simple, upper whorl surface flattened and essentially straight, inclinded at nearly 60° 

to horizontal except for abrupt outward flare to form 

obscure flange at selenizone; outer whorl face limited to 

selenizone, slightly sunken and concave between upper
SYSTEMATIC PALEONTOLOGY 71

and lower borders, each marked by spiral lira; below 

selenizone, basal surface curves steeply downward, degree of inward curvature increasing gradually toward 

columella. Base anomphalous.

Growth lines on upper whorl surface prosocline, 

forming angle of about 45° with suture, proceeding 

straight for approximately inner two-thirds of upper 

surface, then curving slightly more shallowly prosocline before meeting outer angulation; lunulae very 

broad and chevron shaped; growth lines below selenizone very steeply opisthocline for a short distance, 

curving rapidly to orthocline, and proceeding straight 

across basal surface to columella. Ornament of prominent rounded collabral lirae, irregularly spaced but 

most commonly having interpaces three to five times 

width of lirae; lunulae coarser and more uniformly 

spaced, their interspaces about three times as wide as 

lunulae; additional ornament of elongate raised ridges 

extending from near suture down upper whorl face, 

some on collabral lirae and some interspaced between 

them, but with no regularity of pattern.

Dimensions. The holotype is slightly crushed and 

measures 14.3 mm in height, its maximum width about 

11 mm.

Discussion. This species was described and figured 

by Sadlick and Nielsen (1963), who did not propose a 

name for it. We recognize as possibly conspecific 

several poorly preserved specimens in the 

Paracravenoceras barnettense Zone, which are associated with the types of Ptychomphalina burbankensis n. 

sp. We believe that this is an easily recognizable species and propose to name it for Walter Sadlick. We 

choose as the holotype the specimen (USNM 134171) 

figured by Sadlick and Nielsen (1963, pi. 150, fig. 13). 

The other specimen from the same locality (USNM 

134169) figured by them (1963, pi. 148, figs. 12 and 13) 

is designated the paratype. Both specimens lack the 

apical area and are slightly crushed but preserve surface detail extremely well.

Lunulazona sadlicki n. sp. differs from L. costata in 

being larger, in having a flatter upper whorl surface, 

and in having a wider, more obviously bordered and 

slightly more concave selenizone. The subsutural ornament is more prominent than that of L. costata, being 

in the form of elongate collabral ridges extending about 

one-third the length of the whorl surface. The broad 

chevron-shaped lunulae of L. sadlicki also contrast 

with the narrower U-shaped lunulae of the type species.

Lunulazona nodomarginata is a smaller shell having 

its prominent ornament confined mainly to the nodes 

near the suture. Lunulazona sadlicki differs from 

L. utahensis in being larger and higher spired and in 

having much more prominent collabral ornament. The

upper whorl surface of that species is slightly more 

inflated, and its selenizone flat between bordering 

lirae.

We considered the possibility that the features that 

distinguish L. sadlicki from other smaller species of the 

genus might result from continued growth, as the early 

growth stages of this species are not known. However, 

comparison of the younger whorls of these two specimens with whorls of other species at the same size 

permits us to rule out ontogenetic change as being responsible for these differences. It is worth repeating 

that the four species occur at four different levels 

within the Chainman Shale, each one associated with 

a different ammonoid zone.

In addition to the other three Utah species, 

L. sadlicki differs from L.I sablei (Yochelson and 

Dutro) from the Lisburne Limestone of Alaska in being 

higher spired and in having a relatively narrower selenizone, which is nearly vertical, rather than inclined. 

L. lativittata (Girty) from the Fayetteville Shale of Arkansas has a selenizone similar in width and inclination to that of L. sadlicki, but the shell is higher spired 

and its sutures are slightly impressed; it is a much 

smaller species than L. sadlicki.

Types. Holotype USNM 134171; paratype USNM 

134169.

Occurrence and number of specimens. Sadlick and 

Nielsen locality 7-1 (holotype and paratype), 0.3 miles 

(0.5 km) N. 55° E. from Leppy Peak, about 3.5 miles (5.6 

km) north of Wendover, approximately in SW 1/4 SE V4 

sec. 28, T. 34 N., R. 70 E., Elko County, Nev. USGS 

collections 17091-PC (1), 17092-PC (1), 28628-PC (1), 

Juab County, Utah; 717201-PC (3), 25546-PC (2), Millard County, Utah.

Lunulazona utahensis n. sp.

Plate 4, figures 1-4, 16, 17

Diagnosis. Moderately low-spired pleurotomariaceans having broad blunt angulation just below peripheral selenizone; ornament of fine closely spaced collabral lirae.

Description. Shell moderately low-spired, pleural 

angle approximately 90°. Nucleus and early whorls unknown. Body whorl embracing penultimate whorl at or 

just below lower margin of selenizone. Whorl profile 

simple, upper whorl surface inclined nearly at pleural 

angle, remaining constant in slope throughout length, 

except near outer edge where if flares outward to upper 

angulation; outer face consisting entirely of selenizone, 

very steeply inclined downward and nearly vertical, 

flat and relatively broad, between bordering lirae; 

basal whorl surface beginning with sulcate segment 

immediately below selenizone followed by broad blunt
72 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

angulation, which is obscure in early growth stages; 

below angulation, basal surface curving strongly inward to columella; essentially no inflation of base and 

upper whorl surface tending to give shell rhomboidal 

profile. Base anomphalous. Columellar lip extremely 

short, straight, not appreciably reflexed. Slit depth and 

other details unknown, but slit certainly did not exceed 

one-eighth whorl in length.

Growth lines forming angle of about 60° with suture, 

straight for extremely short distance, then bending 

abruptly prosocline and crossing upper whorl surface 

at approximate 45° angle, curving to slightly greater 

angle just before crossing spiral lira at upper angulation; selenizone having broad, extremely shallow 

lunulae; growth lines steeply opisthocline to orthocline 

on outer edge of base, at angulation bending abruptly 

to steeply prosocline, beyond which they proceed 

straight inward and downward. Ornament consisting 

exclusively of coarse threads to fine lirae, rather regular in spacing, interspaces two to three times width of 

lirae.

Dimensions. Holotype and figured paratype, respectively, measure: length 7.9 and 7.4 mm, maximum 

width 7.5 and 7.1 mm.

Discussion. This species is common, associated 

with Cravenoceras hesperium Miller and Furnish and 

"Fayettevillea" n. sp. in the lower part of the Cravenoceras hesperium Zone in the vicinity of the Bishop 

Springs dome, Foote Range. Most of our specimens are 

steinkerns, because the shell is easily peeled when attempts are made to extract a specimen from limestone 

matrix.

Considerable variation is noted among individuals in 

the relative strength of collabral ornament on various 

parts of the shell. On most specimens, the ornament of 

the upper whorl surface is of fairly constant weight. 

However, the lunulae and the ornament of the base 

may be either stronger or weaker than that of the upper surface. This variation is not related to preservation or loss of the outer shell layer.

Lunulazona utahensis is distinguished readily from 

other members of this genus in western Utah by the 

flat selenizone bordered by spiral lirae and by an obscure angulation on the basal surface. It is smaller, 

lower spired, and less prominently ornamented than 

L. sadlicki. It differs from the type species L. costata in 

being also lower spired, but, more importantly, in its 

possession of more regular collabral elements and in 

the presence of a slight angulation on the basal surface; 

the selenizone of L. costata is clearly raised above the 

general surface of the whorl rather than flat and bordered as in L. utahensis. L. nodomarginata is distinguished from L. utahensis by its higher spire and by the 

more prominent subsutural ornament that includes

nodes. L.? sablei (Yochelson and Dutro) is a closely 

similar Alaska species that differs from L. utahensis 

principally in being slightly higher spired. The selenizone of L. ? sablei is not bordered by spiral lirae, but the 

holotype of that species may have lost the outer shell 

layer; paratypes provide no information on this point. 

Finally, L. lativittata (Girty) is a distinctly higher shell, 

though its selenizone is flat and bordered by spiral lirae 

as in L. utahensis.

Types. Holotype USNM 211010; paratypes USNM 

211011-211013, 364702, 364703.

Occurrence and number of specimens . USGS collections 17022-PC (30), 19604-PC (2), 20443-PC (7), 

20444-PC (23), 20445-PC (18), 25260-PC (388), Millard County.

Lunulazona? aff. L.? sablei (Yochelson and Dutro)

Plate 4, figures 26, 27

Mourlonia minuta Yochelson and Dutro, 1960, p. 136,

pi. 13, figs. 4, 5 (not M. minuta Weller, 1915) 

Mourlonia sablei Yochelson and Dutro, 1963, p. 725.

Description. Shell turbiform, moderately low 

spired, stepped, having wide flat peripheral selenizone; 

pleural angle roughly 80°. Nucleus and earliest whorls 

unknown but probably orthostrophic. Suture obscure 

at bottom of angulation, body whorl embracing at lower 

edge of selenizone. Whorl profile in three distinct segments, middle one being selenizone; upper whorl surface simple, sloping fairly straight from suture to upper 

edge of selenizone, steeping slightly with maturity, and 

subsutural part becoming slightly flattened; outer face 

composed entirely of broad flat selenizone, nearly vertical but inclined outward slightly and set off by a wellformed lira above and below; basal surface including a 

short upper segment inclined inward about 30° from 

vertical, bending abruptly to a long, gently inflated 

lower segment. Slit depth and details of aperture unknown.

Growth lines on upper whorl surface inclined 60° to 

suture, prosocline, fairly straight across upper whorl 

surface but curving more strongly prosocline just above 

selenizone; lunulae well curved, symmetrical, fairly 

shallow; growth lines steeply opisthocline immediately 

below lower bordering lira of selenizone, becoming 

rapidly steeper downward to angulation, there bending 

to orthocline and proceeding straight to columella. 

Base anomphalous. Ornament exclusively collabral, 

having lirae on upper whorl surface separated by interspaces about three times as wide; strongest subsuturally and becoming fine and weak near selenizone; 

pattern similar on base but lirae coarser, more regular, 

and slightly more prominent as size of shell increases.

Dimensions. The larger figured specimen measures 8.0 mm in height and 7.5 mm in maximum width.
SYSTEMATIC PALEONTOLOGY 73

Discussion. The Chainman Shale specimens are 

similar to the holotype of L. ? sablei (Yochelson and 

Dutro) from the Lisburne Limestone of northern 

Alaska. On the type specimen of L .? sablei , growth 

lines above the selenizone as well as the lunulae are 

distinct, whereas the lunulae are faint in the Utah 

material. In both, the selenizone is raised and flattened 

rather than bordered by sharp spiral lirae as in L. utahensis. Such differences depend, in part, upon the quality of preservation of the shell surface. Although the 

holotype of L.? sablei is well preserved, no information 

is available as to the amount of individual variation in 

the strength or ornament in the species.

The selenizone of both L.? sablei, and our Utah specimens is approximately 1V2 times as wide as that of 

L. utakensis at comparable growth stages. We consider 

this character sufficiently significant to question the 

placement of the species in Lunulazona. Nevertheless, 

we recognize the possibility that this species may have 

evolved from L. utahensis. Other differences also are 

noted between L. utahensis and L.? aff. L.? sablei. 

Lunulae on L. utahensis are much stronger than on L. ? 

aff. L. ? sablei. The other Utah species of Lunulazona 

differ in their more rhomboidal outlines, as well as 

their more prominent collabral ornament and need not 

be compared further.

This species is common at one locality in the Foote 

Range in a 6-inch (15-cm)-thick bed, where it is associated with Richardsonites merriami (Youngquist) and 

Glabrocingulum (Glabrocingulum} sp. C.; it occurs also 

in what may be a continuation of the same bed near 

Indian Pass.

Figured specimens . USNM 211015, 211016.

Occurrence and number of specimens. USGS collections 15370-PC (35), 16959-PC (5), 17024-PC (2), Millard County.

Genus EUCONOSPIRA Ulrich in Ulrich and Scofield, 1897

Discussion. This genus includes turbiform to 

trochiform subconical pleurotomariaceans having a 

raised two-flanged narrowly concave selenizone at the 

periphery, the periphery itself being very low on the 

whorl. At one extreme are broadly conical shells having a flat base and ornamented both by spiral and collabral lirae, such as the large Late Pennsylvania (Missourian) species Euconospira missouriensis (Swallow). 

At the other extreme are shells that expand to some 

extent with growth and have more sloping, somewhat 

overhanging whorls and rounded bases, such as E. disjuncta Girty. Some of these have rather straight whorl 

slopes, and some are without spiral lirae.

Because the Mississippian species seem to be limited 

to the turbiform shells generally lacking spiral lirae, 

we considered the possibility of subdividing this genus

on the basis of these differences. However, a survey of 

the material in the collection of the USNM shows that 

these characters are interchangeable; all types are 

found in Pennsylvanian and Permian rocks, so we must 

abandon the idea of subgenera. The type species, Euconospira turbiniformis (Meek and Worthen), combines 

the conical spire and ornament of both spiral and collabral lirae with a convex base; spiral lirae also are 

found on some shells having stepped spires. We therefore regard this genus as varying broadly between the 

extremes cited above. 

American Mississippian species of Euconospira. 

desereti n. sp.

disjuncta Girty, 1910

gradilis n. sp.

sturgeoni Thein and Nitecki, 1974

waterlooensis (S. Weller), 1916 (Bembexia) 

Euconospira disjuncta is from the lowermost part of 

the Fayetteville Shale of Arkansas, E. sturgeoni is from 

the Glen Dean Limestone of Illinois, andE. waterlooensis, which was referred to Euconospira by Thein and 

Nitecki (1974, p. 86), is from the Ste. Genevieve Limestone in Illinois.

Thein and Nitecki (1974, p. 88-90) described and 

figured three additional species as Euconospira sp. 

indet. The first species, from the Golconda Formation of 

Illinois, has the same apical angle as E. waterlooensis 

and certainly is very closely related to, or conspecific 

with, that species. The second species is from the same 

formation and, as they pointed out, is like E. disjuncta, 

except that the selenizone is covered by the succeeding 

whorl. The third species, from the lower part of the 

Okaw Limestone ("Marigold oolite") is not a Euconospira but probably belongs in Spiroscala.

Euconospira desereti n. sp.

Plate 4, figures 5-11, 15

Diagnosis. Turbiform pleurotomariaceans having 

prominent flanged selenizone and closely spaced, 

coarse collabral ornament.

Description. Nucleus unknown. Shell conical in 

general shape, with gently convex base; pleural angle 

approximately 70°, or slightly greater. Whorls in early 

part of shell embracing preceding whorl at or just below 

lower edge of selenizone; more mature whorls embracing slightly lower on preceding whorl. Suture not 

prominent. Profile of upper whorl surface nearly flat, 

except in early whorls which are gently convex, inclined at slightly steeper angle than pleural angle as 

lowermost part of this surface turns abruptly outward 

and nearly horizontal to form narrow flange; outer 

whorl face includes concave selenizone in upper part, 

bordered below by another flange extending a little 

farther laterally than upper flange and forming periph-
74 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

ery; lower side of this flange having little curvature, 

extending farther inward than upper flange, bending 

abruptly downward to lower segment of outer whorl 

face, which is about as high as width of flange above it, 

delineated from base by fairly sharp basal angulation 

accentuated by slight thickening at maturity; basal 

surface inclined strongly inward and gently downward, 

having slight convexity for more than three-fourths of 

its total width, inner part curving upward and flattening. Base anomphalous, having little or no depression 

in columellar area.

Growth lines simple on upper whorl surface, sweeping gently and uniformly prosocline from suture, forming angle of 45° with outer edge of upper flange bordering selenizone; orthocline on lower surface of lower 

flange of selenizone, bending steeply prosocline to form 

angle of nearly 80° with lower edge of flange; continuing straight for one-third distance across basal surface, 

then curving gently to form broad, exceedingly shallow 

sinus, its greatest depth coinciding with change of slope 

on basal surface, finally continuing straight to columellar area. Ornamented by collabral lirae separated 

by slightly wider interspaced paralleling growth lines. 

Selenizone relatively narrow, strongly concave between bordering flanges so as to be nearly semicircular 

in profile; lunulae prominent, symmetrical, strongly 

curved and closely spaced but having some individual 

variation in shape; slit depth unknown. Inner lip variable, partly reflexed on some specimens; outer lip unknown.

Dimensions. Holotype and figured paratype measure, respectively: height 12.5 and 9.0 mm, and greatest width 12.7 and 10.2 mm.

Discussion. This species is based upon a lot of five 

specimens collected near the top of the formation in the 

Burbank Hills. One of the paratypes shows vestiges of 

the original color pattern (pi. 4, figs. 8, 15). This pattern consists of alternating dark and light curved 

splotches on the upper whorl surface, following the general curvature of the growth lirae, the dark splotches 

normally covering four to six interspaces and the light 

splotches, three to four interspaces.

E. desereti differs from E. disjunct a. Girty in having 

a smaller pleural angle and a generally constant inclination of the whorl slope during growth. E. disjuncta 

has a broad, somewhat stepped spire, and the whorl 

slope increases steadily with growth. Although the apical angle in the holotype is slightly less than 80° and 

the pleural angle is 87°, the upper whorl face on one 

side of the final whorl of the holotype diverges at an 

angle of 102° to that face on the other side of the same 

whorl; this angle contrasts with 74° for the final whorl 

of the holotype of E. desereti. E. disjuncta also has faint 

spiral lirae on the early whorls not present on E. 

desereti.

E. sturgeoni Thein and Nitecki differs from E. 

desereti in having a narrower pleural angle, ranging 

from about 65° to 70° in the Illinois species and 70° to 

80° in the Utah form, and in having finer collabral 

lirae. E. waterlooensis (S. Weller) is based on an immature specimen having an apical angle of 48°. Its narrow 

shape and finer collabral lirae readily distinguish it 

from E. desereti.

Types . Holotype USNM 211020; paratypes USNM 

211021, 211022, 364704.

Occurrence and number of specimens . USGS collections 17021-PC (1), 17217-PC (5), 25319-PC (1), 

28612-PC (2), Millard County.

Euconospira gradilis n. sp.

Plate 4, figures 12-14

Diagnosis. Moderately high-spired turbiform pleurotomariaceans having slightly stepped spire.

Description. Nucleus and early whorls unknown, 

shell conical, turbiform; height slightly greater than 

width; pleural angle approximately 65°; body whorl 

embracing penultimate whorl just below basal angulation so that on spire periphery overhangs early part of 

succeeding whorl. Sutures distinct, slightly impressed. 

Whorl profile simple; upper whorl surface nearly flat, 

uniform from suture to near edge, where bordered by 

narrow flange; outer whorl face consisting of concave 

selenizone between two flanges, lower one at periphery, and a segment about twice width of selenizone, 

inclined at about 20° to axis of coiling, straight, bordered below by basal angulation bearing cord; basal 

surface gently inflated but essentially inclined 45° to 

axis of coiling. Base anomphalous.

Growth lines simple on upper whorl surface, sweeping gently prosocline from suture to form angle of about 

50° with upper edge of selenizone; lunulae deep and 

U-shaped; growth lines opisthocline on flange below 

selenizone, curving to steeply prosocline on outer whorl 

face, meeting basal angulation at angle of about 60°, 

continuing straight onto base for about one-third distance across it, then curving to orthocline and continuing inward; younger stages curving prosocline just before reaching columella, but mature stages reducing 

and then nearly losing this inner gentle curvature. Ornament predominantly collabral; upper surface of 

whorl bearing low, rounded, fairly coarse lirae and interspaces twice to three times width of lirae, this ornament becoming obscure at maturity; lunalae strong; 

ornament also strong on lower part of outer whorl face 

and outer edge of base, more prominent than on upper 

surface, but diminishing rapidly in height inward, 

merging into growth lines for most of width of base; two 

or three spiral lirae crossing collabral elements, but not 

apppearing too persistent throughout growth; some
SYSTEMATIC PALEONTOLOGY 75

faint spiral lines also visible on inside surface of base 

where shell has flaked off internal mold.

Dimensions. Holotype measures 10.3 mm in height 

(apex missing) and 10.1 mm in greatest width.

Discussion. This species is based on a specimen 

from a bed bearing the ammonoid Richardsonites merriami (Youngquist) in the Conger Range. Although additional representatives have not yet been found, this 

unique specimen is easily distinguished from Euconospira desereti n. sp. and, in fact, from all other 

Euconospira known to us. Its name refers to the somewhat steplike spire.

Euconospira gradilis differs from E. desereti n. sp. in 

having a relatively higher shell with a smaller pleural 

angle, a slightly impressed suture, and a lower locus of 

embracement of the whorls, so that each whorl overhangs the upper part of the succeeding one. The prominence of a cordlike angulation below the selenizone 

also distinguishes this species from others in the 

Chainman Shale. The course of the growth lines on the 

upper whorl surface is slightly steeper in this species 

and markedly different on the base, as E. desereti lacks 

any distinct basal reentrant. Finally, the ornament of 

this species is finer, especially on the base, than on E. 

desereti.

Perhaps the most closely related species is E. disjuncta Girty, which also has overhanging whorls and, 

locally, faint spiral sculpture. However, E. disjuncta is 

a much broader shell, the holotype having a pleural 

angle of 87°, in comparison with 65° for the type of E. 

gradilis. The divergence of slope on the final whorl of 

E. disjuncta is 102° in comparison with 90° for E. 

gradilis.

Type. Holotype USNM 211023.

Occurrence. USGS collection 22880-PC, Millard 

County.

Family LOPHOSPIRIDAE 

Subfamily RUEDEMANNINAE

Genus WORTHENIA Koninck, 1883

Discussion. Late Paleozoic pleurotomariaceans 

that may be described in general as turreted and having most of the volume of their whorl below the peripheral selenizone have not been subjected to any modern 

attempt at systematic subdivision. The description of 

Yochelsonospira Thein and Nitecki (1974, p. 98-100) 

provides a needed taxon for the nontabulate forms. We 

concur fully with those authors in placing Yochelsonospira under the Ruedemanninae. However, we believe that the distinctions from Worthenia, stated as 

"***being more conical and by lacking a lower angulation on the outer face" (Thein and Nitecki, 1974, 

p. 100), are gradational characters. It seems to us more

reasonable at the current state of our knowledge to 

regard Yochelsonospira as a subgenus of Worthenia, 

thus considering the presence or absence of a lower 

angulation as a subgeneric feature. Although no 

abrupt separation exists between the two subgenera, 

the literature indicates that W. (Yochelsonospira) is 

more commonly a Mississippian taxon and W. (Worthenia) typically a Pennsylvanian and Permian one.

As members of the typical subgenus, among those 

American species listed by Yochelson and Saunders 

(1967, p. 241-244), we would include: W. castlemanensis Linz from the Conemaugh Formation of Maryland, 

W. subscalaris (Meek and Worthen) from the Pennsylvanian of Illinois, and probably W. speciosa (Meek and 

Worthen) from the same area. Worthenia tabulata 

(Conrad), the type species of this genus was described 

originally from western Pennsylvania. It is the most 

common and widespread member of this genus in 

North America and has been reported throughout the 

Pennsylvanian System and into the Early Permian. 

Casual observation of several populations identified as 

this species convinces us that this long-ranging taxon 

could readily be divided into several species having 

shorter geologic ranges.

We also examined younger Permian species of 

Worthenia listed by Yochelson and Saunders (1967), 

and we question whether any of them is correctly assigned to this genus. New generic taxa may have to be 

erected to accommodate them. However, it is beyond 

the bounds of this paper to discuss and reassign them.

Worthenia? marcouiana (Geinitz) from the Late 

Pennsylvanian of Nebraska has a concave selenizone. 

It is reassigned herein to Glabrocingulum (Ananias); 

Yochelson examined the type specimen at Harvard 

University's Museum of Comparative Zoology. Worthenia textiligera (Meek) from the "Waverly Group" of 

Ohio has closely spaced spiral ornament and a slight 

subsutural ramp, and the raised selenizone is gently 

convex; we here reassign it to Mourlonia. Worthenia 

longi Bell from Subzone B of the lower part of the Windsor Series, Nova Scotia, has the distinctive stepped outline of Borestus; the figures and description given by 

Bell (1930, p. 625, pi. 23, figs. 12-14) suggest that it 

has a shallow concave selenizone near the middle of the 

outer face, so we hereby transfer it to Borestus.

Pleurotomaria (Cyclonema?) strigillata Herrick from 

the "Waverly Group" of Ohio was transferred to 

Worthenia by Hyde (1953, p. 327). We examined specimens from near Granville, Licking County, Ohio, 

which may be topotypes. This species is moderately 

high spired, has four spiral carinae on the angulations, 

three of them prominent; the sinus is narrow and moderately deep, centering on the most prominent carina, 

the third counting downward from the suture; it is not 

a selenizone. We know of no genus to which this species
76 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

can be assigned and for the present must classify it as 

"Worthenia" strigillata.

Subgenus W. (YOCHELSONOSPIRA) Thein and Nitecki, 1974

Discussion. Although the differences from Worthenia listed by Thein and Nitecki would seem sufficient 

to separate two taxa of generic rank, our examination 

and redescription of Worthenia (Yochelsonospira) 

tenuilineata (Girty), given below, shows that they probably do not have high taxonomic value. The absence of 

a lower angulation in this group is most interesting. In 

the position at which this angulation would be expected 

to develop in W. (Worthenia), the spiral ornamentation 

is more widely spaced than elsewhere, and secondary 

lirae are present. Clearly, because of the wide spacing 

of the lirae, this general region of the shell was secreted 

by a part of the mantle that was not greatly wrinkled 

and thus under slight tension. It would take little 

change in the growth pattern for a broad angulation to 

form in this shell area.

Type species. Yochelsonospira pagoda Thein and 

Nitecki [ Worthenia tenuilineata Girty].

American Mississippian species of Worthenia 

(Yochelsonospira). 

mississippiensis (White and Whitfield), 1862

(Pleurotomaria)

nauvooensis (Worthen), 1884 (Pleurotomaria) 

northviewensis (S. Weller), 1899 (Mourlonia) 

tenuilineata Girty, 1929 [synonym: Yochelsonospira pagoda Thein and Nitecki, 1974.] 

thomasi Elias, 1958

Two of these species are assigned unquestionably to 

this subgenus: Mourlonia northviewensis S. Weller 

from the Northview Shale of Missouri, and Worthenia 

tenuilineata (Girty), which is a senior synomym of the 

type species, from the uppermost part of the 

Fayetteville Shale of Arkansas. Three other species, 

discussed below, are assigned with less certainty to the 

subgenus.

We examined a plaster cast of the holotype of Pleurotomaria mississippiensis White and Whitfield from the 

Kinderhookian Series of Iowa. This species certainly 

does not belong in Mourlonia , its last generic assignment, perhaps by mistaken identity, as Knight (1944, 

pi. 185, figs. 1, 2), in referring it to Mourlonia, illustrated this species by inadvertently reproducing 

Meek's figures of Pleurotomaria textiligera Meek. The 

shape of the spire of P. mississippiensis is like that of 

Worthenia , but the base and sculptural details are not 

preserved on the plastoholotype. We are arbitrarily assigning P. mississippiensis to W. (Yochelsonospira) because of its Early Mississippian age, but more details 

are needed before its status can be established firmly.

Pleurotomaria nauvooensis Worthen from the 

Keokuk Formation of Illinois is fairly large and has a 

shape resembling that of W. (Yochelsonospira); we 

questionably assign it to the subgenus. The illustration 

of the type is that of a steinkern lacking a basal angulation. Topotype specimens in the collection of the 

USNM are also steinkerns. Until this species can be 

redescribed from authentic well-preserved specimens, 

we recommend that use of the name be confined to the 

type lot.

Worthenia thomasi Elias from the Redoak Hollow 

Member of the Goddard Shale of Oklahoma is known 

from a single fragment of an external mold. If this 

specimen is a Worthenia, it may be assigned to W. 

(Yochelsonospira) because the reconstructed outline 

drawing provided by Elias (1958, text-fig. 4) shows no 

basal angulation, and none appears on the photograph 

of the fragment (Elias, 1958, pi. 2, fig. 15). W. thomasi 

is so poorly known that we recommend that this name 

also be restricted to its type lot. As noted earlier, the 

likelihood of obtaining topotypes from Elias's Redoak 

Hollow localities is virtually nil.

Worthenia (Yochelsonospira) tenuilineata Girty

Plate 7, figures 1-5

Worthenia tenuilineata Girty, 1929b, p. 141, figs.

16-18. 

Yochelsonospira pagoda Thein and Nitecki, 1974,

p. 101, 102, fig. 39 a-d. 

Worthenia (Yochelsonia) tenuilineata. Gordon and

Yochelson, 1983, p. 985, figs. 3V-X, NN-PP.

Diagnosis. Wide, slightly turreted, subconical 

pleurotomariaceans having sloping flat whorls and 

rounded base, ornamented by numerous spiral lirae 

crossed by growth lirae.

Description. Nucleus orthostrophic, smooth, probably about two whorls, passing gradually into postnuclear whorls. Shell having slightly turreted appearance, showing subtle but distinct ontogenetic change; 

pleural angle near 80°. Whorl profile of early growth 

stages simple, inclined, selenizone nearly flat and of 

essentially same inclination; succeeding whorl embracing at base of selenizone; sutural area and selenizone 

on later whorls becoming more prominent and whorl 

embracing lower. Mature whorl profile having obscure 

suture, but bordering suture distinct and incised, set off 

from rest of whorl by a nearly horizontal ramp occupying almost one-sixth of total width of upper whorl surface, causing slightly turreted aspect of whorls; upper 

whorl face beyond ramp bending abruptly downward 

and outward at approximately 45° inclination, continuing straight to outer edge where it flares slightly and 

thickens; periphery rounded, formed by selenizone; 

outer whorl face immediately below periphery curving
SYSTEMATIC PALEONTOLOGY 77

abruptly inward for short distance, then downward and 

gently inward for most of its length, and finally inward 

to form elongate sigmoidal curve; junction with basal 

surface fairly well rounded, base gradually flattening 

toward columella and forming approximate 20° angle 

with horizontal. Slit and details of apertural lips not 

preserved.

Growth lines obscure across ramp, prosocline at 45° 

angle to angular margin of ramp, having slight curvature across main part of upper whorl surface, but 

swinging backward more strongly adjacent to selenizone; below selenizone, steeply opisthocline for short 

distance, but approximately orthocline across rest of 

outer whorl face, gently sigmoidal crossing basal curvature, then orthocline for most of distance across base. 

Surface ornamentation finely reticulate, consisting of 

narrow collabral threads having slightly wider interspaces crossed by spiral threads that appear on first 

postnuclear whorl and continue to aperture; intersections of two sets of threads minutely beaded; collabral 

threads slightly stronger on upper whorl face.

Dimensions. The two illustrated Chainman Shale 

specimens (USNM 211018 and 211019, from the Foote 

Range and the Burbank Hills, respectively) and the 

holotype from Arkansas (USNM 119394) have the following measurements:

USNM 211018 119394 211019

Height --------...-. 18.0 15.1 14.2

Maximum width - - - - 15.5 14.5 14.0

Discussion. Our specimens were compared with 

the holotype (USNM 119394) from the upper part of the 

Fayetteville Shale in northwestern Arkansas. The Arkansas specimen comes from a lower stratigraphic 

horizon, where it was associated with the lower Eumorphoceras (Ej) Zone ammonoids Cluthoceras glicki (Gordon) and Tumulites varians McCaleb, Quinn, and Furnish. In Utah, this species is restricted to equivalents of 

the upper Eumorphoceras (E2) Zone; that is, it is common locally in the Cravenoceras hesperium Zone and 

continues upward stratigraphically beyond the highest 

occurrence of Richardsonites merriami (Youngquist) in 

the various Chainman sections.

The holotype has 17 spiral threads on the upper 

whorl face, including the ramp, two fairly strong 

threads and, locally, two very fine flanking threads in 

the selenizone, and about 40 threads on the outer face 

and base, some them very fine and intercalated between stronger ones. The specimen illustrated on plate 

7, figures 3-5, has 18 threads on the upper whorl face, 

four on the selenizone, and 37 on the outer face and 

base. The number of threads on the upper whorl face, in

our specimens, ranges from 14 to 20 and on the outer 

face and base, from 36 to 45.

We compared the holotype of Worthenia (Yochelsonospira) pagoda Thein and Nitecki with that of W. 

tenuilineata Girty and regard them as conspecific. W. 

(Y.) northviewensis (S. Weller) differs from this species 

in being lower spired, having the whorls more deeply 

incised, and in lacking the sutural ramp.

Other species assigned provisionally to W. (Yochelsonospira) are not well understood and are therefore 

difficult to compare. W. (Y.) thomasi Elias is represented only by a fragment of an external mold bearing 

finely reticulate sculpture similar to that of W. (Y.) 

tenuilineata, but Elias's reconstructed outline drawing 

of this species is markedly different in shape. W. (Y. ) 

mississippiensis (White and Whitfield), of which the 

base and surface sculpture are unknown, differs from 

W. (Y.) tenuilineata in having a somewhat steeper 

upper whorl face and in being much larger. W. (Y.) 

nauvooensis (Worthen) is known only from steinkerns 

and therefore cannot be compared.

Pleurotomaria nevadensis Walcott, from the Late 

Mississippian Diamond Peak Formation of Nevada, is 

superficially similar to W. (Y.) tenuilineata because of 

its closely spaced ornament. The shell, however, is 

much larger and has a narrower pleural angle and a 

concave selenizone. It is reassigned in this report to 

Glabrocingulum (Ananias) and is briefly redescribed 

on p. 66.

Figured specimens. USNM 211018, 211019.

Occurrence and number of specimens. USGS collections 17095-PC (1), Juab County; 15161-PC (2), 

15364-PC (1), 716997-PC (1), 17021-PC (2), 17023- 

PC (35), 17024-PC (1), 17056-PC (2), 17059-PC (1), 

17209-PC (1), 17217-PC (2), 17219-PC (2), 17310-PC 

(5), 25259-PC (1), 25274-PC (8), 25318-PC (2), 25319- 

PC (5), 25547-PC (1), 25551-PC (2), 725553-PC (1), 

Millard County.

Family PHYMATOPLEURIDAE 

Genus CATAZONA Gordon and Yochelson, 1983

Discussion. The Phymatopleuridae constitute a 

closely knit group of pleurotomariaceans having a relatively narrow selenizone that tends to be flat except for 

bordering lirae. Several different shell shapes and relative heights of spire occur in the family, and distinction 

between the genera is not entirely obvious. Catazona 

resembles Borestus Thomas, 1940, in having a turbinate shell that develops a flat or gently concave, 

approximately vertical outer whorl face, clearly 

bounded by upper and lower angulations. The shell 

thus has a somewhat turreted appearance. In Borestus, 

the selenizone is in the middle of the outer whorl face.
78 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

In Catazona, it is at the bottom of this face, adjacent to 

the suture of the succeeding whorl. So far, only one 

species of Catazona is known, originally described from 

the Diamond Peak Formation in eastern Nevada.

Catazona rudilirata Gordon and Yochelson

Plate 7, figures 22-27

Catazona rudilirata Gordon and Yochelson, 1983,

p. 986, figs. 3 GG^JJ.

Diagnosis. Phymatopleurids having sloping upper 

whorl surface ornamented by four strong spiral cords; 

outer whorl surface vertical, bordered by keels, bisected by spiral cord, lower half occupied by selenizone. 

Base anomphalous, with channeled umbilical depression and bearing five or six spiral cords. Collabral 

growth lirae threadlike.

Description. Shell low spired, pleural angle near 

95°. Nucleus and early whorls unknown. Suture obscure; body whorl embracing penultimate whorl at 

lower edge of selenizone. Upper whorl face having flat, 

nearly horizontal ramp adjacent to suture, occupying 

about one-fourth of total width of this face, ending 

abruptly at a spiral cord; beyond cord, inner half of 

upper whorl surface is straight and inclined downward 

at approximately 45°, bisected by a second cord, ending 

at a third, and finally curving downward and outward 

for about one-fourth of total surface width of this face to 

form prominent protruding flange. Outer whorl face 

below upward-curved flange narrow, inclined inward 

but nearly vertical above selenizone, which is about 

twice as wide and more distinctly inclined. Basal surface consisting of at least four beveled segments, separated by cords, each segment being more strongly inclined toward the horizontal than the preceding one. 

Base anomphalous, having faint broad umbilical depression bordered by a cord. Inner lip curved, flattened. 

Inductural deposit covering flat part of inner lip and 

base of columella. Outer lip and slit unknown, but slit 

depth probably much less than one-sixth of whorl.

Growth lines not preserved on upper surface, flange, 

and upper part of outer whorl face; selenizone raised 

slightly, relatively broad; lunulae well formed, symmetrical, closely spaced, moderately prominent. 

Growth lines on inner half of base prosocline, straight. 

Ornament on upper surface consisting of three spiral 

cords; four or five on basal surface, those on base 

slightly larger and more rounded in profile than those 

on upper surface.

Dimensions. Both figured specimens measure 

12.0 mm in height; their respective widths are 13.0 mm 

and 14.2 mm.

Discussion. The description above is based on specimens from the Confusion Range, Utah. These consist

of five lots of somewhat varied preservation, four from 

the Willow Gap Member of Sadlick (1966) at Wallet 

Gulch and Skunk Spring and one from an equivalent 

level in the Granite Mountain measured section. One is 

an incomplete specimen preserved in limestone, of 

which the shell substance is recrystallized calcite; this 

and another lot were found in the Skunk Spring section. Some parts of the ornament are well preserved, 

but other parts have been lost by breakage along cleavage faces. The lunulae of the selenizone are well preserved, but the edges of the selenizone are missing so 

that it appears narrow. The other two lots are silicified 

specimens from the Wallet Gulch section. These specimens preserve no growth lines and several are broken, 

but collectively they illustrate the base and show the 

selenizone to be a wide band.

The type lot from the Diamond Peak Formation exposed in the White Pine Range, Nev., is under USNM 

numbers 307494 and 307495.

Figured specimens. USNM. 211024, 211025.

Occurrence and number of specimens. USGS collections 17104-PC (1), Juab County; 15358-PC (1), 

15362-PC (1), 17214-PC (7), 25566-PC (2), Millard 

County.

Genus DICTYOTOMARIA Knight, 1945

Discussion. Our arguments for considering Dictyotomaria a full genus, rather than a subgenus of Glyptotomaria Knight, as suggested by Batten (1958, 

p. 210), were given in an earlier paper (Gordon and 

Yochelson, 1975, p. F16). This genus includes depressed turbiform to subtrochiform shells having a 

sloping upper whorl surface, more steeply sloping outer 

face, and a gently convex base. Sculpture consists normally of sharp collabral and spiral lirae. Growth lirae 

are straight below the suture, curve backward to the 

selenizone, and are straight below it, also forming a 

shallow sinus on the base. The selenizone, located at 

the middle of the outer face, is bordered by a cord at 

either side, and the collabral lirae form lunulae within 

it. The base normally has a narrow umbilicus or umbilical chink. The poorly preserved Chainman shells referred questionably to this genus are unusual in that 

the pleural angle is comparatively small for the genus. 

North American Mississippian species of Dictyotomaria. 

brazeriana (Girty), 1927 (Phanerotrema) 

carlbransoni Gordon and Yochelson, 1975 

meekana (Hall), 1857 (Pleurotomaria) 

wortheni (S. Weller), 1916 (Ptychomphalus) 

yochelsoni Thein and Nitecki, 1974 

Elias (1958, p. 9, pi. 1, fig. 14; pi. 2, fig. 7) cited as 

"Phymatopleura brazerianum var. springerensis 

n. var." a single tiny shell from the Redoak Hollow
SYSTEMATIC PALEONTOLOGY 79

Member of Goddard Shale in southern Oklahoma, having a maximum diameter of 2 mm. As this name was 

published prior to 1961, according to the International 

Code of Zoological Nomenclature (International Trust 

for Zoological Nomenclature, 1961, p. 45), it is subject 

to interpretation as either a subspecific or intrasubspecific entity. Elias stated that the Redoak Hollow 

shell is so similar in all respects to P. brazeriana that 

it can be identified with it assuredly. Then, he went on 

to point out that it differs in one respect, the presence 

of a low revolving costa in the selenizone. However, 

Elias's illustrations are insufficient to confirm this. Because we know of no Dictyotomaria having a spiral cord 

within the selenizone, we conclude that the variety 

springerensis is probably not a valid subspecies of Dictyotomaria brazeriana and do not, therefore, follow 

Thein and Nitecki (1974, p. 108) in referring Elias's 

taxon to this genus.

Thein and Nitecki (1974, p. 108) also referred 

Ptychomphalus depressus S. Weller to Dictyotomaria, 

but we are omitting this species because the presence of 

a selenizone, let alone its precise position, is not known, 

nor is the configuration of the collabral lirae. A relationship to some other pleurotomariacean such as Portlockiella cannot be precluded at present, or even some 

nonpleurotomariacean genus like Yunnania.

Dictyotomaria? sp.

Plate 7, figures 34-36

Discussion. Occurring with Catazona rudilirata in 

the basal bed of Willow Gap Member of Sadlick (1966), 

in the Wallet Gulch section, is a smaller, more slender, 

spirally lirate shell having the upper whorl surface 

sloping at 52° to the horizontal and a fairly short nearly 

vertical face below the periphery. The specimen consists of approximately four whorls; the nucleus is not 

preserved. The pleural angle is 57° in the figured specimen. Although silicification has obliterated fine details of the shell, five or six cords can be discerned, 

ornamenting the sloping whorl face, the strongest cord 

being at the periphery. On the vertical outer face, just 

below this cord, is a depressed spiral zone believed to be 

the selenizone. Perhaps two more cords occur in the 

lower part of this face. Collabral lirae cannot be distinguished anywhere on the shell.

The succeeding whorl is inserted immediately below 

the angulation that forms the lower boundary of the 

outer whorl face. The base is gently convex and seems 

to be ornamented by several fine spiral cords, but these 

likewise have been obscured by the silicification. The 

columella is somewhat twisted and the outer lip recurved, partly concealing a narrow depressed area; a 

tiny umbilicus may be present. The height of the figured specimen is 6.4 mm and the width 4.9 mm.

On the basis of the general configuration of the shell 

and the possible presence of a selenizone, we questionably refer this shell to Dictyotomaria, which it resembles more than any other genus. A small even more 

poorly preserved specimen also is referred here.

Figured specimen. USNM 211071.

Occurrence and number of specimens. USGS collection 25566-PC (2), Millard County.

Superfamily MURCHISONIACEA

Discussion. Yochelson (1984) suggested a major review of the present arrangement of some of the highlevel taxa within the Archaeogastropoda, which is followed herein and accounts for the change in systematic 

position of the Murchisoniacea. When the "Treatise" 

(Knight, Batten, and Yochelson, 1960) was written, the 

view prevailed that the prosobranchs could be divided 

into archaeogastropods and caenogastropods, the latter 

equivalent to the Mesogastropoda and Neogastropoda 

then in use. The murchisoniaceans were viewed as a 

transitional group between the two suborders, for, although they possessed a selenizone, some members of 

the superfamily had features suggesting a siphonal 

canal and hence an exhalent siphon.

Additional data, partly from the Mesozoic, suggest 

that lumping of the Neogastropoda with the Mesagastropoda was a retrograde step in classification. It now 

seems clear that most of the genera within these taxa 

are post-Paleozoic in their origin. In his speculation on 

high-level classification, Yochelson (1984) broadened 

considerably the limits of morphologic types placed 

within the early Pleurotomariacea. He also suggested 

that all slit-bearing groups be placed in the same suborder, so that Pleurotomariacea, Bellerophontacea, and 

Murchisoniacea would be linked together. We follow 

that course here, for it is our view that, in a sense, the 

Murchisoniacea are merely a convenient way of distinguishing exceptionally high-spired pleurotomariaceans. Accordingly, we abandon the suborder 

Murchisoniina.

Family MURCHISONIIDAE 

Genus STEGOCOELIA Donald, 1889

Subgenus S. (STEGOCOELIA) Donald, 1889

Discussion. This subgenus includes small, moderately high spired shells having rounded whorls ornamented by prominent threads or carinae. A short slit 

and selenizone occur above the periphery. A thin parietal inductura is present at the aperture, covering part 

of the columellar area. Thein and Nitecki (1974, 

p. 161-166) recognized three species in the Late Mississippian of Illinois and Kentucky.
80 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

American Mississippian species of Stegocoelia (Stegocoelia). 

illinoisensis (S. Weller), 1916 (Solenospira) 

kentuckiensis Thein and Nitecki, 1974 

okawensis Thein and Nitecki, 1974 

Chesterian species of S. (Hypergonia) and of the allied genus Aclisina were discussed by Thein and 

Nitecki (1974).

Stegocoelia (Stegocoelia) sp.

Plate 9, figures 16, 17

Discussion. One tiny murchisoniid shell came from 

a bed near the top of the Cravenoceras hesperium Zone 

in the Burbank Hills section. The specimen is incomplete, retaining nearly four whorls, and measures 

4mm in height. A selenizone cannot be determined 

clearly, making generic reference uncertain. We refer 

it to Stegocoelia mainly because of its strong spiral 

lirae, which occur over the entire whorl. Sutural areas 

are incised, but the sutures are faint and smooth. The 

whorl profile beneath the lirae is smoothly curved but 

not greatly inflated; the basal whorl surface is slightly 

flattened, but the juncture of the outer and basal surfaces is well rounded, if the lira in this region is ignored. The periphery occurs a little below midwhorl. 

The columellar lip is straight and does not appear reflexed; the outer lip is unknown.

Four spiral lirae ornament the whorls, two of them 

near the suture, the subsutural one faint. The third lira 

is at the periphery and separated by a relatively wide 

space from the second lira. The fourth lira is midway 

between the periphery and the next suture. The base is 

ornamented by three lirae that are equally spaced and 

progressively lower toward the center. Growth lines 

curve strongly from opisthocline to prosocline on the 

base; they cannot be observed clearly on the upper part 

of the whorl. Impressions that follow growth lines are 

steeply opisthocline on the periphery and lower part of 

the whorl.

A second lot of five poorly preserved, silicified specimens was collected near the top of the Chainman Shale 

in the measured section at Granite Mountain. These 

specimens are from a stratigraphic position similar to 

that of the specimen described above and seem to represent the same species.

A substantial number of American Mississippian 

high-spired gastropods have been referred to Murchisonia or to the generally similar Stegocoelia, but our material is too poor to make any meaningful comparisons.

Figured specimen. USNM 211036.

Occurrence. USGS collections 25252-PC (5), Juab 

County; 17209-PC (1), Millard County.

Genus BELLAZONA, n. gen.

Diagnosis. Simple meekospiriform shells bearing a 

selenizone; whorls gently convex; base anomphalous, 

basal lip moderately well rounded; sutures very 

slightly impressed. Shell surface polished; ornament 

obscure or absent; selenizone located low on whorl, suture at its midline.

Type species. Loxonema bella Walcott, 1884.

Discussion. Although there might be some hesitancy in proposing a new genus while some older 

generic concept not rigorously defined might be extended, we feel that the term "unique" can be aptly 

applied to Bellazona. The shape of this genus simulates 

that of Loxonema and Meekospira, but the presence of 

a selenizone readily distinguishes Bellazona. However, 

none of the pleurotomariaceans described from the Paleozoic approach this shell form. Among the murchisoniaceans, as presently constituted, the Silurian genus 

Leptorima has the selenizone high on the whorl. Other 

genera, such as the Devonian Ptychocaulus and the 

early Carboniferous Cerithioides, have the selenizone 

lower on the whorl but not at the suture as in Bellazona; they differ further in having a turritelliform 

shape.

Except for the type species and one additional new 

species, no other taxa are assigned to this genus. Walcott overlooked the faint selenizone on his material. 

Mid-Paleozoic species variously assigned to Subulites, 

Loxonema, and Meekospira, among other genera, 

should be examined for this feature. Such a search cannot be made from published illustrations and must be 

deferred until type material of the described species is 

available.

Bellazona bella (Walcott)

Plate 9, figures 11-15

Loxonema bella Walcott, 1884, p. 258, pi. 14, figs. 1, la.

Diagnosis. Narrowly meekospiriform selenizonebearing gastropod shell having well-rounded lip.

Description. Earliest whorls consisting of approximately one low smooth nuclear whorl followed by much 

higher, smooth postnuclear whorls. Shell like that of 

Meekospira; apical angle about 25°. Whorl profile simple; periphery very low on whorl, slightly below upper 

edge of selenizone, so that outer whorl face is nearly 

flat except immediately above slightly sunken sutural 

area. Whorl surface below periphery, curving smoothly 

inward and continuing downward; basal part of whorl 

somewhat less arched. Body whorl embracing penultimate whorl at midline of selenizone. Selenizone obscure, set off only by faint groove above and below. 

Shell surface polished. Growth lines closely spaced and 

faint, orthocline near suture, very steeply prosocline
SYSTEMATIC PALEONTOLOGY 81

for most of their length, then curving to more strongly 

prosocline near selenizone, which they join at nearly a 

45° angle; lunulae obscure; below selenizone, growth 

lines curving from opisthocline at 45° to orthocline, 

continuing straight across anomphalous base. Whorls 

ornamented by five or more exceedingly faint spiral 

lirae above selenizone and at least one on base. Aperture seemingly without inductura; slit depth unknown.

Dimensions. Walcott's type specimen is 17.5 mm 

long and 6.5 mm wide.

Discussion. Welcott apparently described this species from a single well-preserved specimen, USNM 

14410. It came from a small conical hill on the east side 

of Secret Canyon road, about 3 miles southeast of Eureka, Nev. The Mississippian beds at that locality are 

currently assigned to the Diamond Peak Formation 

and are late Meramecian in age.

The holotype is moderately well preserved, though it 

is attached to a piece of matrix for part of its length. For 

most of the length on one side, the shell is broken away, 

but 11 postnuclear whorls occur. On the other side and 

around the circumference of the body whorl, shell is 

present. The aperture is broken, and the shell is exfoliated just behind it. The shell surface is polished, and 

the selenizone is even more obscure than in the other 

species, B. polita, so that Walcott's error in assigning 

his shell to Loxonema is understandable. The holotype 

shows exceedingly faint spiral lirae, but we cannot find 

these on the specimens from the Chainman Shale, specimens on which the surface is fairly well preserved; we 

are inclined to place little emphasis on these faint lirae 

as a specific character.

The Utah specimens of B. bella are from the measured section at Granite Mountain at or near the top of 

the Goniatites americanus Zone and immediately above 

the limestone marker bed in the lower part of the 

Chainman Shale. The apex is missing on all specimens, 

but fragments of the shell surface are preserved, several of which show the selenizone. The figured specimen retains approximately seven whorls.

Figured Utah specimen . USNM 211037.

Occurrence and number of specimens. USGS collection 17018-PC (4), Juab County.

Bellazona polita n. sp.

Plate 9, figures 22-25

Diagnosis. Moderately wide meekospiriform 

selenizone-bearing gastropods having poorly rounded 

basal lip.

Description. Nuclear whorls unknown; early and 

mature stages showing consistent growth pattern with 

no evidence of ontogenetic change. Shell form similar 

to that of Meekospira; apical angle 35°. Whorl profile

simple, almost flat from suture to periphery, then curving slightly inward for short distance so that suture is 

obvious but not impressed. Selenizone occupying approximately one-fifth of outer whorl; body whorl embracing penultimate whorl at midline of this feature; 

periphery occurring in upper part of selenizone, which 

follows general contour of whorl surface and is delimited only by faint groove above and below. Whorl profile below selenizone curving smoothly into anomphalous base; basal surface more flattened than 

peripheral area above it. Shell surface smooth, polished, ornamented only by faint closely spaced growth 

lines. Growth lines orthocline from suture to about 

halfway down side of whorl, then curving gradually to 

become steeply prosocline, meeting selenizone at angle 

of approximately 60°; lunulae well curved but faint; 

below selenizone, growth lines opisthocline at angle of 

about 45° but rapidly curving forward to become orthocline on inner half of basal surface. Base ornamented by three or more faint spiral grooves. Aperture 

seemingly without inductura. Slit depth unknown.

Dimensions. The holotype, which lacks the apex, 

measures 17 mm in length and 8.3 mm in width.

Discussion. Bellazona polita is fairly widespread in 

the Chainman Shale; we found it from Granite Mountain southward nearly to Conger Mountain. Although 

not abundant, it is more common than other highspired gastropods in the fauna. Most of the specimens 

are from the Goniatites granosus Zone, but two lots are 

from the Paracravenoceras barnettense Zone. One is an 

incomplete specimen preserving part of the selenizone 

and is found in association with Cravenoceras kingi 

(Hall and Whitfield). The other lot consists of poorly 

preserved and partly crushed specimens from about the 

same stratigraphic level near Skunk Spring. This species is distinguished from B. bella (Walcott) by its apical angle, which is about 10° wider than that of B. bella , 

and by its less well-rounded base.

Types. Holotype USNM 211038; paratypes USNM 

211039-211041.

Occurrence and number of specimens. USGS collections 17012-PC (17), 17015-PC (8), 17020-PC (2), 

25562-PC (1), Juab County; 14553-PC (2), 14557-PC 

(4), 20455-PC (1), Millard County.

Suborder "MACLURITINA"

Discussion. Since 1960, the Euomphalacea have 

been combined with the Macluritacea under the suborder Macluritina. We have reservations whether the 

two superfamilies are in fact closely related. Most euomphalaceans are low spired and dextral in coiling. 

Some euomphalaceans do have a flat or nearly flat 

basal surface, resembling that of Maclurites. This
82 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

shape could result from a sedentary life habit in which 

the base of the shell rested on the substrate. The base 

need not indicate close relationship to the presumed 

hyperstrophically coiled Macluritacea. Our use of quotation marks in the subordinal assignment indicates 

our disbelief in this relationship, but, at this time, we 

cannot suggest any reassignment of the Euomphalacea 

to a larger group.

Superfamily EUOMPHALACEA

Family EUOMPHALIDAE 

Genus STRAPAROLLUS DeMontfort, 1810

Subgenus S. (EUOMPHALUS) J. Sowerby, 1814

Discussion. Straparollus is a long-ranging genus of 

distinctive but limited shell characters. It is recognized 

easily and is rarely confused with other gastropod genera. Currently, it is divided into six subgenera, on the 

basis of the spire configuration and angularity and the 

smoothness or nodosity of the whorls. These subgenera 

are: S. (Straparollus), S. (Euomphalus), S. (Philoxene), 

S. (Serpulospira), S. (Amphiscapha), and S. (Cylicioscapha). For the distinguishing characters of these 

taxa, the reader is referred to Yochelson (1956) and 

Knight, Batten, and Yochelson (1960). Linsley and 

Yochelson (1973, p. 19) suggested that Philoxene not be 

used as a separate taxon, and the interested reader is 

referred to their work. Only S. (Euomphalus) has been 

found in the Chainman Shale of Utah; it is represented 

by three species described below.

Shells of this subgenus have low to depressed spires 

and an angulation at the junction between the upper 

and outer whorl faces. S. (Euomphalus) generally has 

a widely phaneromphalus base, which in some species 

is marked by a subangulation and may bear nodes; 

some forms also have nodes along the outer edge of the 

upper whorl face. The name S. (Phymatifer) has been 

used for species having nodes top and bottom, but we 

are following Knight, Batten, and Yochelson (1960) in 

regarding S. (Phymatifer) as a junior synonym of S. 

(Euomphalus).

Species of S. (Euomphalus) having a depressed spire 

and whorls that are angular both below and above are 

very similar to S. (Amphiscapha). We refer such forms 

to S. (Euomphalus) if the whorls of the spire are shallowly stepped; if steps are absent and the whorls tilt 

toward the apex, the shells belong in S. (Amphiscapha). One Chainman species of this type seems almost intermediate between S. (Euomphalus) and S. 

(Amphiscapha) and was named S. (Euomphalus) intermedius by Gordon and Yochelson (1983). The other 

Chainman species is more typical of the subgenus, as it 

has a low elevated spire and nodes along the rounded 

base. This species is named S. (Euomphalus) nodibasis 

n. sp.

American Mississippian species of Straparollus (Euomphalus). 

angularis Weller, 1900 

boonensis (Swallow), 1863 (Euomphalus) 

brooksensis Yochelson and Dutro, 1960 

exortivus (Dawson), 1868 (Euomphalus) 

illinoisensis Thein and Nitecki, 1974 

intermedius Gordon and Yochelson, 1983 

latus (Hall), 1858 (Euomphalus) 

multistriatus (E. Branson), 1938 (Euomphalus) 

nodibasis Gordon and Yochelson, n. sp. 

obtusus (Hall), 1858 (Euomphalus) 

pancakensis Mount, 1973

planodorsatus (Meek and Worthen), 1961 (Euomphalus )

roberti (White), 1862 (Euomphalus) 

similis Meek and Worthen, 1862 

subplanus (Hall), 1852 (Euomphalus) 

tricarinatus (Girty), 1927 (Phymatifer?) 

utahensis Hall and Whitfield, 1877 

xylacus Gordon and Yochelson, 1977 [n. name for 

S. (E.) calix Gordon and Yochelson, 1975, not 

calyx Phillips, 1836].

Omitted from the list are (1) Euomphalus luxus 

White, 1877, a junior synonym of Straparollus (Euomphalus) subplanus, according to Yochelson (1962, 

p. 77); (2) E. perspectivus Swallow, 1863, a synonym of 

S. (E.) planodorsatus; and (3) Straparollus similis var. 

planus Meek and Worthen, 1861, a variant of S. (E.) 

similis. Euomphalus boonensis Swallow is known only 

from the original description, which suggests that it 

was a very typical S. (Euomphalus); it was never figured, and the type presumably was destroyed in a fire 

at the University of Missouri along with other Swallow 

types. Because its provenance was listed only as the 

"Encrinital Limestone" in Missouri, it probably can 

never be recognized.

Straparollus (Euomphalus) nodibasis n. sp.

Plate 3, figures 6, 11-17

Straparollus (Euomphalus) n. sp. Gordon and Yochelson, 1983, p. 979.

Diagnosis. Low-spired euomphalid gastropod, lacking basal angulation, ornamented by nodes on basal 

surface.

Description. Nucleus and earliest growth stages 

unknown; early whorls narrowly rounded on top; whorl 

becoming steplike at early stage. Sutures distinct, not 

channeled or incised. Upper whorl surface arches outward and gently downward from suture for more than 

two-thirds of whorl width, beyond which it flattens and 

curves concavely upward to form inner and upper edge 

of carina separating upper and outer whorl surfaces. 

Upper surface becoming less arched but more steeply
SYSTEMATIC PALEONTOLOGY 83

inclined with maturity; carina low in early whorls, located on strong angulation in mature whorls. Outer 

whorl surface steeply inclined outward and downward, 

becoming slightly bowed near periphery, which is below midwhorl, and curving inward near base, following 

arc of circle which continues up steeply into umbilicus, 

so that no basal angulation is formed. Body whorl embracing penultimate whorl above periphery. Umbilicus 

rather widely phaneromphalus.

Shell ornamented by closely spaced faint growth 

lines over entire whorl, which become stronger in late 

maturity, and by moderately large nodes on lowest part 

of whorl. Growth lines on upper whorl surface straight, 

gently prosocline, approaching angulation of whorl at 

angle of approximately 60°, nearly orthocline on upper 

one-third of outer whorl face, and just above periphery 

curving to prosocline, at approximately 30° to vertical, 

continuing in this direction into umbilicus, but becoming orthocline again a short distance before reaching 

umbilical suture. Nodes slightly elongate parallel to 

growth lines; interspaces wider than nodes, reaching 

maximum width, twice those of nodes. Fifteen or more 

nodes on mature whorl.

Dimensions. The holotype measures 7.1 mm wide 

and 5.0 mm high; a large paratype (USNM 210959) is 

36 mm wide and 22.5 mm high.

Discussion. The whorl profile of this Chainman 

species is similiar to that of S. (Euomphalus) brooksensis 

Yochelson and Dutro, another Late Mississippian form, 

but the latter species lacks nodes on the basal surface. 

S. (E.) planodorsatus (Meek and Worthen), from the 

Chesterian Series of Illinois, differs in having a weak 

circumbilical angulation as well as in lacking the basal 

nodes. The only North American species of Mississippian age that seems to have a nodose character similar 

to that of the Chainman species is S. (E.) sp. B of 

Knight (1953, p. 76) from Sonora, Mexico. Knight's material is so incomplete, however, that no further meaningful comparisons can be made.

A somewhat similar Pennsylvanian species was described from the "Lower Coal Measures" of Alton, 111., 

as S. (E.) pernodosus Meek and Worthen. This species 

is slightly larger, the upper carina is more rugose, and 

the base upon which the nodes are located is narrower 

and flanked toward the umbilicus by a concave zone, 

inside of which the whorl rounds rather rapidly into the 

umbilicus. The nodes are elongate in the direction of 

the whorl. S. (E.) nodibasis differs from this species 

primarily in that the base is flatter and the nodes are 

near the umbilicus and are transversely elongate.

A straparollid similar to S. (E.) nodibasis occurs in 

northern England and is called S. (E.) nodosus (Sowerby). A large incomplete specimen of this shell in the 

U.S. National Museum collection (USNM 6346) measures 83 mm in diameter. The eight nodes on the base 

are rounded to longitudinally elongate. These nodes 

contrast with those of the Utah species, which number 

about 12 to 15 on each whorl and which tend to elongate transversely.

The subgenus Phymatifer Koninck, based upon a 

nodose species of straparollid, has been considered a 

subjective synonym of Euomphalus for many years. 

Eventually it might find utility again, if the various 

species of nodose euomphalids can be shown to represent a single lineage. The use of Koninck's subgenus for 

the Chainman Shale species, however, poses difficulties, because typical Phymatifer has nodes on both 

the upper and lower whorl surfaces. The significance 

that might be placed on nodose ornament in these gastropods needs careful study.

Only a few specimens of this easily recognized species were found. The species ranges nearly throughout 

the Willow Gap Member of Sadlick (1966) at Skunk 

Spring, where the top 10 feet (3 m) of this unit contains 

many large corals of the genus Caninia (K2 Zone of 

Dutro and Sando, 1963, p. 1974). At Granite Mountain, 

S. (E.) nodibasis has been found in a similar Caniniabearing unit and also in another bed a few feet higher 

stratigraphically.

Types. Holotype USNM 210958; paratypes USNM 

210959, 210960.

Occurrence and number of specimens. USGS collections 17098-PC (1), 17104-PC (1), Juab County; 

15355-PC (I), 15358-PC (1), 15362-PC (1), 15375-PC 

(I), 717188-PC (I), 25563-PC (1), Millard County.

Straparollus (Euomphalus) intermedius Gordon and Yochelson

Plate 3, figures 1-5, 7-10

Straparollus (Euomphalus) intermedius Gordon and 

Yochelson, 1983, p. 977-978, pi. 2, figs. 12-23. 

Discussion. This species is placed in S. (Euomphalus) because the spire is stepped for the last several 

volutions, the umbilicus is deeper than in typical S. 

(Amphiscapha), and the whorl is tilted slightly toward 

the umbilicus rather than toward the apex as in typical 

S. (Amphiscapha). Its depressed spire and fairly sharp 

upper carina suggests S. (Amphiscapha), and it seems 

to be intermediate between these two subgenera of 

Straparollus. The stratigraphic position in the Upper 

Eumorphoceras (E2) Ammonoid Zone not far below the 

first appearance of S. (Amphiscapha) agrees with this 

concept. S. (Amphiscapha) is typically a Pennsylvanian subgenus, but we have identified it in the lowermost Ely Limestone at Granite Mountain and in the 

Diamond Peak Formation in the Carlin region of Nevada; at both these occurrences, it is in uppermost Mississippian strata.
84 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

In western Utah, S. (E. ) intermedius is known from 

several localities. Six specimens were associated with 

the ammonoid Carvenoceras hesperium Miller and Furnish collected from the Foote Range at the northwestern side of the Bishop Springs dome. These specimens 

were obtained from a shale, and the imbrications along 

the carina are particularly well developed, even on 

young specimens. These imbrications result from interruption of growth accompanied by slight flaring of the 

lip at the upper angulation; some specimens have more 

than 40 such expansions. Some specimens appear 

darker on the upper and outer whorl faces than on the 

umbilical surface; this difference could reflect an original color pattern.

One figured specimen (pi. 3, figs. 7-10) lacks the 

rugosity. The nucleus and early whorls are fairly well 

preserved in this specimen; they are depressed and flat 

topped. This shell comes from a limestone bed in the 

Conger Range containing the ammonoid Richardsonites merriami (Youngquist) and is therefore in a 

higher ammonoid zone than that of the Foote Range 

lot. In this and other specimens from higher beds, the 

shape of the conch is similar to that seen in the type lot, 

but serrations are very poorly developed and appear 

only as slight irregularities along the carina between 

the upper and outer whorl faces. The smoother surface 

of these specimens probably is not due to preservation 

in limestone, because rugose specimens occur in limestone in the Cravenoceras hesperium Zone. Whether or 

not partial weathering is responsible for these differences is not clear. We currently are including the 

smoother specimens in the same species as the more 

rugose ones, though eventually another name might be 

justified.

Among described species, S. (E. ) intermedius is most 

similar to S. (E. ) subsulcatus Knight from the Middle 

Pennsylvanian; the primary difference is in the greater 

arching of the umbilical walls of the Chainman form. 

Another species comparably depressed is S. (E) xylacus 

Gordon and Yochelson, from the Amsden Formation of 

Wyoming. That species differs in having a flatter, less 

saucer-shaped upper surface, an obtuse upper angulation that lacks imbrications, and a relatively deep umbilicus that is infundibuliform in general aspect.

S. (E.) illinoisensis Thein and Nitecki from the 

Menard Limestone of Illinois has a shell of similar 

shape in that its spire is depressed. However, it differs 

from S. (E. ) intermedius by its larger overall size, its 

slightly lower conch, and the lack of serrations along 

the upper carina; in addition, it has an impressed suture and a flat sloping base, rather than the somewhat 

convex base of S. (E. ) intermedius.

S. (E.) n. sp. B. of Easton (1962, p. 99) from the 

Cameron Creek Member of the Tyler Formation of

Montana, is superficially similar to S. (E. ) intermedius 

but differs in being relatively higher, in having the 

outer whorl face inclined toward the base, and in having a sharp carina. Better material is needed to determine whether this species should be referred to S. (Amphiscapha).

Figured specimens. USNM 210954-210957.

Occurrence and number of specimens. USGS collections 17088-PC (2), 17099-PC (1), 25252-PC (1), Juab 

County; 715355-PC (2), 15365-PC (1), 17003-PC (2), 

17021-PC (2), 17023-PC (6), 17029-PC (5), 22880-PC 

(1), 25547-PC (3), 25551-PC (1), 25566-PC (6), Millard County.

Straparollus (Euomphalus) sp.

Plate 8, figures 21-24

Description. Conch depressed turbinate; spire 

broadly subconic, of moderate height; pleural angle 

about 100°. Only last two whorls fairly well preserved. 

Whorl attaching a little above periphery of preceding 

one; suture rather deeply impressed; upper whorl face 

sloping gently upward for a short distance from suture, 

forming a narrow tilted ramp bounded by a narrow 

rounded ridge; beyond this ridge, whorl slopes downward at approximately 45° to periphery, forming a faint 

sigmoidal curve, convex part near ramp and concave 

part near periphery. Fairly sharp angulation, almost a 

keel at periphery; whorl rounded below, a little less 

convex in middle, but not flattened. Base broadly 

phaneromphalous, umbilicus occupying nearly onethird of width; aperture vaulted above, rounded below. 

Growth lines indistinct, nearly obliterated by partial 

silification of shell, but, where visible, appearing orthocline to slightly opisthocline.

Dimensions. The specimen measures (in mm): 

height 14.0, width 25.5; height of aperture 10.0; width 

of aperture 9.5.

Discussion. A third species assignable to S. (Euomphalus ) is represented by a unique specimen from a bed 

in the northern part of the Needle Range. This bed also 

contains the ammonoid Richardsonites merriami 

(Youngquist).

This species is clearly distinct from the two previously described forms, differing from S. (E.) intermedius Gordon and Yochelson in having a raised spire 

and from S. (E. ) nodibasis n. sp. in the absence of nodes 

on the base. Otherwise, it is similar to these forms in 

shape. It differs from S. (E. ) pancakensis Mount in that 

the upper ridge on the whorl is near the suture, rather 

than midway along the slope of the upper whorl surface, as in that species. More specimens are needed to 

determine the range of variation in this species before 

it can be formally named.
SYSTEMATIC PALEONTOLOGY 85

Figured specimen. USNM 348023. 

Occurrence. USGS collection 15161-PC (1), Millard County.

Suborder TROCHINA 

Superfamily PLATYCERATACEA

Family PLATYCERATIDAE 

Genus PLATYCERAS Conrad, 1840

Subgenus P. (PLATYCERAS) Conrad, 1840

Discussion. Coiling of the early whorl or whorls 

distinguishes the typical subgenus from P. (Orthonychia). The genus Platyceras is rare in the Chainman 

Shale. A single specimen of P. (Orthonychia) has been 

described from the Cravenoceras hesperium zone in 

east-central Nevada (Gordon and Yochelson, 1983). 

Other Chesterian species have been noted by Thein and 

Nitecki (1974).

American Mississippian species of Platyceras 

(Platyceras). 

circulare Rowley, 1901

haliotoides Meek and Worthen, 1866

latum Keyes, 1889

nasutum Miller, 1891

oxynotum Girty, 1929

reversum Hall, 1860

subelegans Girty, 1910

subrotundum Snider, 1915

Platyceras encloides S. Weller, P. evolutus S. Weller, 

and P. glenparkensis S. Weller from the Glen Park 

Limestone Member of the Sulphur Springs Formation 

at Glen Park, Mo., and Platyceras pulcherrimum Rowley from the Saverton Shale and Louisiana Limestone 

near Louisiana, Mo., were listed in P. (Platyceras} by 

Yochelson and Saunders (1967); all are from rocks now 

considered Upper Devonian. The species listed above 

need review because some of them were founded on a 

single specimen and because the shape and growth 

lines in Platyceras are commonly influenced by the 

echinoderm to which this gastropod attached itself.

Platyceras (Platyceras) cf. P. (P.) subrotundum Snider

Plate 8, figures 1-4

Platyceras subrotundum Snider, 1915, p. 118, pi. 7, figs.

10, 11. 

Platyceras (Platyceras} subrotundum. Thein and

Nitecki, 1974, p. 122-123, fig. 50.

Discussion. Two specimens of Platyceras occur in 

the Chainman Shale and a third is questionably identified. The first two are moderately well preserved but 

not complete; the greatest dimension of the figured

specimens measures 18 mm. The early whorls are in 

contact; they are coiled in a plane nearly parallel to 

that of the upper whorl surface, which is so very gently 

convex as to be nearly flat. At maturity, the early 

whorls seem to be depressed with respect to the upper 

whorl surface, but the specimen is not complete enough 

for us to be certain. The whorls expand rapidly in 

width, and the mature whorls seem somewhat geniculate; this feature could be caused, however, by slight 

postburial compaction of the shell. The outer whorl 

face, including the periphery, is well rounded; the 

whorl cross section is suboval. The columellar lip is 

thickened and the outer lip crushed in this specimen. 

The shell surface is smooth; growth lines form a prominent sinus at the periphery and a second shallower 

sinus on the upper whorl face at maturity.

Despite the relatively good preservation of two of the 

three specimens, the rarity of this species precludes 

any estimate of the amount of individual variation. The 

shells seem very similar to those of Platyceras (Platyceras) subrotundum Snider, particularly as interpreted 

by Thein and Nitecki (1974, p. 122, fig. 50 a-e) and on 

the basis of specimens from the Glen Dean Limestone 

of Illinois. This species is the only Platyceras (Platyceras) formally named from Chesterian rocks in the 

United States. Snider's specimens are from the Mayes 

Formation, Fayetteville Shale, and Pitkin Limestone 

in eastern Oklahoma. Only the lack of sufficient wellpreserved specimens from the Chainman Shale precludes a more positive determination of this species.

The figured specimen was found weathered out approximately 50 feet (15.2 m) below the top of the Chainman Shale, associated with the brachiopod Carlinia 

phillipsi (Norwood and Pratten) in the Jensen Wash 

measured section in the Burbank Hills. The second 

specimen is from approximately the same stratigraphic 

position in the measured section at Granite Mountain. 

A similar specimen, lacking most of the shell, has been 

identified from the lower part of the Ely Limestone at 

Granite Mountain.

The platyceratids were a group of gastropods that 

lived commensally on crinoids (Keyes, 1888; Bowsher, 

1955, p. 1-9); they are exceptionally rare on other pelmatozoans. Their extreme rarity in the Chainman 

Shale corresponds to the scarcity of crinoid remains in 

most of this formation. These gastropods, however, 

were not found with the one crinoid genus, Agassizocrinus, that is in great abundance locally. This crinoid 

genus unlike other crinoid genera may not have provided a desirable site for Platyceras.

Figured specimen. USNM 211029.

Occurrence and number of specimens. USGS collections 17059-PC (1), 25548-PC (1), Millard County; 

17101-PC (1), Juab County.
86 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Genus STROPHOSTYLUS Hall, 1859

Discussion. This genus includes platycerataceans 

that resemble in outline the neritacean genus Naticopsis but that differ in having fewer whorls, a more irregular flaring shape, a twisted columella, and in lacking 

a thick inductura.

North American Mississippian species of Strophostylus. 

chesterensis Thein and Nitecki, 1974 

nevadensis Gordon and Yochelson, 1983 

?tantillus Gordon and Yochelson, 1983 

wortheni (S. Weller), 1916 (Naticopsis) 

Thein and Nitecki (1974, p. 139) included S. splendens Girty, 1915, in this genus, but in this paper we 

transfer that species to Naticopsis (Naticopsis).

Strophostylus cf. S. nevadensis Gordon and Yochelson

Plate 8, figures 6-8

Strophostylus nevadensis Gordon and Yochelson, 1983,

p. 988, figs. 3T, U.

Discussion. Specimens of Strophostylus were collected at three localities in Utah, all of them from beds 

in the upper part of the Cravenoceras hesperium Ammonoid Zone. The shells are naticiform, rapidly flaring, 

and anomphalous, having two to three postnuclear 

whorls, the nucleus consisting of 1 V4 smooth whorls, as 

closely as can be determined. The early whorls are 

somewhat raised and tilted. The largest specimen, 

slightly distorted, is about 14.5 mm high and 14.5 mm 

wide. Most shells are much smaller; the one figured is 

4.9 mm high and 4.8 mm wide. The final volution is 

well rounded, gently convex above, moderately convex 

at the periphery, and more strongly convex at the base. 

In the early part of the shell, the whorl joins the preceding one almost at the top of the upper whorl surface; 

however, as the shell grows, the line of juncture moves 

gradually downward to the periphery of the whorl, giving the short spire a tilted appearance. The columella 

is slightly twisted and reflexed toward the outer lip.

The shell surface is smooth and polished. Growth 

lines are very fine, strongest near the suture, where 

they emerge at an angle of about 45°, are curved and 

prosocline, becoming straighter across the periphery 

and base. These lines are crossed by very faint spiral 

lirae. No inductura is present.

In shape, this species is similar to Strophostylus 

wortheni (S. Weller) from the Ste. Genevieve Limestone of Illinois; it differs mainly in that the western 

shells are subequal in height to width, whereas S. 

wortheni is wider than high and has a lower spire. Our 

shells are most like S. nevadensis Gordon and Yochelson from the Cravenoceras hesperium Zone in the Diamond Peak Formation in the White Pine Range, Nev.

They are particularly like the paratype of that species, 

which has a slightly elevated spire. In this regard, however, they differ slightly from the holotype of S. 

nevadensis (USNM 307498), in which the spire is almost flush with the upper surface of the final whorl. 

More material is needed both from the Nevada and 

Utah localities to determine whether this difference is 

intraspecific or whether two species are actually involved. For this reason, we only compare the Utah 

shells with those of the Nevada species, rather than 

making a positive identification.

Figured specimen. USNM 211079.

Measured specimen. USNM 341966.

Occurrence and number of specimens. USGS collections 25252-PC (2), Juab County; 25269-PC (1), 

25271-PC (3), 25563-PC (4), Millard County.

Family HOLOPEIDAE 

Subfamily GYRONEMATINAE

Genus CINCLIDONEMA Knight, 1945

Discussion. To the best of our knowledge, the only 

species of this genus thus far described is the type species, Cinclidonema texanum Knight, from the Middle 

Pennsylvanian of Texas. The taxon we describe below 

constitutes the first report of Cinclidonema from the 

Mississippian. However, another Mississippian species, from the "so-called Boone Chert" (Moorefield Formation) near Batesville, Ark., also belongs in this 

genus. Girty (1915b, p. 37) described five specimens 

from one locality as Pleurotomaria aff. carbonaria Norwood and Pratten but did not illustrate any of them. 

Apparently, the numerous spiral lirae led him to believe that a selenizone was present. Reexamination of 

this material shows no indication of a selenizone, and 

we regard this lot as typical Cinclidonema.

Apart from the shape, the spiral lirae, which are 

closely spaced from the suture to the innermost part of 

the base, constitute the most characteristic feature of 

the genus. These prominent lirae are papillose or pustulose where crossed by the growth lines.

Cinclidonema sp.

Plate 7, figures 18-20

Discussion. This identification is based on a single 

crushed shell from the Granite Mountain section. During life, the specimen was turbiform, having an elongated subglobose body whorl. The periphery is high on 

the whorl, and the body whorl embraces the penultimate whorl at or just below the periphery. The outer lip 

is prosocline, inclined about 30° from vertical; the inner 

lip does not appear to be thickened. A small umbilical 

chink is present. Numerous closely spaced spiral lirae 

are present, having interspaces about the same width
SYSTEMATIC PALEONTOLOGY 87

as the raised ornament. Growth lines are equally 

prominent and closely spaced so that the surface is 

covered with a network. At the intersection of the spiral and inclined elements, the surface is roughened. In 

C. texanum, the surface is distinctly papillose, whereas 

in this species, the network intersections are more pustulose, being lower and broader; in the type species, the 

growth lines are finer.

Figured specimen. USNM 211026.

Occurrence. USGS collection 28628-PC (1), Juab 

County.

Superfamily MICRODOMATACEA 

Family ELASMONEMATIDAE

Genus ANEMATINA Knight, 1933

Discussion. This genus contains small gastropods 

having a spire of moderate height, a fairly smooth surface ornamented only by fine collabral threads, and a 

minute umbilicus.

American Mississippian species of Anematina. 

micula (Girty), 1909 (Macrocheilust) 

proutana (Hall), 1856 (Holopea) 

rockymontana (Shimer), 1926 (Loxonema)

Anematina sp.

Plate 8, figure 5

Discussion. This record is based upon four tiny gastropods, the best preserved of which is figured. It is a 

shell of approximately four whorls, from the lower part 

of the Cravenoceras hesperium Ammonoid Zone, in the 

Foote Range, where it occurs with Loxonema lautum n. 

sp. The shell is 1.8 mm high and 1.15 mm wide, the 

spire accounting for 27 percent of the height. The 

whorls are gently convex, the suture not impressed. 

The surface is smooth, and the shell is so minute that 

growth lines have not been observed. This species is 

known only from one locality.

Figured specimen. USNM. 348024.

Occurrence and number of specimens. USGS collection 25260-PC (4), Millard County.

Suborder NERITOPSINA

Superfamily NERITACEA

Family NERITOPSIDAE

Subfamily NATICOPSINAE

Genus NATICOPSIS M'Coy, 1846

Subgenus N. (NATICOPSIS) M'Coy, 1846

Discussion. This subgenus includes moderately 

low-spired Naticopsis in which the smoothly curved 

whorl profile is not excessively elongated either laterally or vertically.

North American Mississippian species of Naticopsis 

(Naticopsis). 

buttsi Gordon and Yochelson, 1982

carleyana (Hall), 1857 (Natica)

clinovata n. sp.

confusionensis n. sp.

dubia Rowley, 1901

genevievensis Meek and Worthen, 1867

glomerosa Gordon and Yochelson, 1983

hartti Bell, 1929

howi Dawson, 1868

inornata (Walcott), 1894 (Platystoma)

madisonensis Worthen, 1884

mariona Thein and Nitecki, 1974

picta Girty, 1912

splendens (Girty), 1915 (Strophostylus)

suturicompta Yochelson and Dutro, 1960

variata (Phillips), 1836 (Natica) of Rollins, 1975

waterlooensis S. Weller, 1916

ziczac Whitfield, 1882

Naticopsis depressus Winchell, 1863, from the 

"Chonopectus sandstone" (English River Formation) of 

Iowa, and N. paucivolutus S. Weller, 1906, from the 

Glen Park Limestone Member of the Sulphur Springs 

Formation of Missouri, were listed by Yochelson and 

Saunders (1967, p. 140,142) as Mississippian species of 

Naticopsis (Naticopsis) but are from beds now considered to be very Late Devonian in age.

We hereby transfer Platyostoma inornatum Walcott, 

from the Diamond Peak Formation of Nevada, to N. 

(Naticopsis). The holotype (USNM 14407) is mainly a 

steinkern, but a few fragments of thick smooth shell 

adhere on the basal part. The upper surface of the 

whorl is rather flat, and the spire is higher than that of 

N. (N.) madisonensis. The base of the steinkern has a 

depression similar to that in N. (N.) madisonensis because the shell and inductura are missing. The height 

of the specimen is 43 mm and the width 41 mm. The 

associated fauna is late Meramecian in age.

During this study, a few observations were made on 

some of the other species of N. (Naticopsis) listed above, 

and these observations may be of some use to future 

workers. N. (N.) madisonensis Worthen, from the 

St. Louis Limestone in Illinois, is a large oblongly 

ovate species. A cast of the holotype in the USNM collection (69172) has a greatest dimension of 56 mm, 

measured along the final whorl but diagonal to the 

shell axis; measurements of height and width are 53 

and 54 mm, respectively. What Worthen interpreted as 

a deep umbilicus seems to be a depression due to partial 

collapse of the middle of the base of the shell; it may 

also be due in part to loss of the inductura and perhaps 

the underlying shell.

N. (N.) picta Girty, from Chesterian rocks in Indiana, has a very low spire, as the final whorl joins the 

penultimate whorl well above the periphery; the spe-
88 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

cies seems to have a fairly wide inductura. It also has 

raised growth lirae that ramify toward the base, particularly in the subsutural region. The holotype (USNM 

144816) is ornamented by color markings having a 

zigzag pattern. (N.) ziczac Whitfield, from the Maxville 

Limestone of Ohio, has a shell with ornamentation similar to that of N. (N.) picta, but the zigzag pattern is 

incised on the shell surface rather than being expressed 

as color markings. We do not agree with the interpretation of Girty (1912, p. 339) that these are growth striae.

Easton (1962, p. 100, pi. 13, fig. 13a, b) described and 

figured as Naticopsis cf. N. remex (White) a specimen 

from the Heath Formation of south-central Montana. 

White's Upper Carboniferous species came from the 

lower part of the Aubrey Group of Arizona. All but one 

of White's eight syntypes (USNM 8063) are steinkerns, 

some retaining patches of shell. The one fairly complete 

specimen has a low broad spire, the sutures not impressed, the upper whorl face broad, and the aperture 

flaring. We refer this entire lot to Planospirina remex 

(White). The Montana specimen (USNM 118874) differs in having a higher spire of well-rounded whorls, an 

impressed suture, subsutural riblets on the early 

whorls, and a prominent subsutural ramp. We transfer 

Easton's shell to the synonymy of N. suturicompta, 

with which it agrees in all salient characters.

Finally, judging from the illustrations of Bell (1929, 

pi. 31, figs. 12-15), more than one species may have 

been included in N. howi Dawson from the lower part 

of the Windsor Series of Nova Scotia. Part of this material may belong in Naticopsis, but in the subgenus N. 

(Marmolatella); other specimens may be Strophostylus. 

However, until authentic material is restudied, the 

species should be retained in the typical subgenus.

Naticopsis (Naticopsis) confusionensis n. sp.

Plate 8, figures 13-18, 26

Diagnosis. Subglobose Naticopsis having an extremely well-rounded whorl profile; spire of moderate 

height; surface polished; inductura absent.

Description. Earliest growth stage not known; juvenile and more mature whorls exceptionally well 

rounded, their profile essentially following arc of circle 

throughout its length; spire of moderate height, occupying nearly one-quarter of height of shell. Sutures not 

impressed, smooth, but nevertheless apparent. Final 

whorl embracing penultimate whorl at periphery. Mature lip having only slight basal thickening; inductura 

seemingly absent. Shell without ornamentation, surface polished; growth lines closely spaced, very fine, 

simple, steeply prosocline from suture to base of columella. Shell structure of at least two layers; outer 

layer quite thin and possibly darker colored near suture than on principal part of whorl.

Dimensions. The holotype and figured paratype 

are, respectively 12 and 8.2 mm in length and 11.3 and 

8.0 mm in width.

Discussion. The three primary types are single 

specimens from three localities in the upper part of the 

Chainman Shale. The holotype is from the Caniniabearing limestone unit in the Granite Mountain measured section. Also included in this species but with 

some question are four specimens from a bed in the 

Willow Gap Member of Sadlick (1966) in the Skunk 

Spring measured section. These differ from the typical 

form in having somewhat lower spires.

Within the Chainman fauna, the smaller naticopsids 

can be confused easily with specimens of lanthinopsis. 

This similarity is superficial, because well-preserved 

specimens of lanthinopsis have a parietal fold on the 

columella; moreover, the whorls increase in size more 

slowly in that genus. For many species of Naticopsis, 

virtually the only distinguishing feature is the shape of 

the whorl. We lack any precise practical method, other 

than pure description, for expressing subtle changes in 

shape.

N. (N.) carleyana (Hall), from the Salem Limestone 

of Indiana, is similar in shape toN. (N.) confusionensis 

but differs from it in having a somewhat lower spire, 

the final whorl attaching to the penultimate whorl a 

little above the periphery, in having tiny riblets adjacent to the suture, and in having over the columella a 

thick inductura that becomes concave toward the basal 

lip.

Other Late Mississippian species that differ from N. 

(N.) confusionensis in having subsutural riblets are N. 

(N.) suturicompta Yochelson and Dutro, from the Alapah Limestone of northern Alaska, N. (N.) genevievensis Meek and Worthen, from Chesterian rocks in Missouri and Illinois, N. (N.) buttsi Gordon and Yochelson 

(1982b) from beds of St. Louis age in the Greenbrier 

Limestone of southwestern Virginia, and AT. (N.)glomerosa Gordon and Yochelson (1983) from the Diamond 

Peak Formation in east-central Nevada.

Most of the North American Late Mississippian species now included in Naticopsis (Naticopsis) have 

smooth shells without subsutural ornamentation, each 

succeeding whorl smoothly appressed at the suture. 

Several species among these differ from N.(N.) confusionensis in having a decidedly elongated oval shape. 

These include AT. (N.) hartti Bell, from the lower part of 

the Windsor Series of Nova Scotia, N'. (N.) splendens 

(Girty), from the Batesville Sandstone of Arkansas, 

and N. (N.) waterlooensis Worthen, from the Ste. 

Genevieve Limestone of Illinois. N. (N.) splendens 

closely resembles N. (N.) confusionensis in general 

shape of the whorl, in having a polished finely striate 

surface, and in the apparent lack of an inductura. It
SYSTEMATIC PALEONTOLOGY 89

differs in having a shell about half the size of that of N. 

(N.) confusionensis, a lower spire, and recurved and 

shallowly sigmoidal growth lines on the base.

Types. Holotype USNM 211030; paratypes USNM 

211031, 211032.

Occurrence and number of specimens. USGS collections 25257-PC (1), 20547-PC (1), Juab County; 

14559-PC (1), 15159-PC (1), 15359-PC (1), 15362- 

PC (1), 715363-PC (4), 17003-PC (1), 17021-PC (1), 

22876-PC (4), Millard County.

Naticopsis (Naticopsis) cf. N. (N.) genevievensis 

Meek and Worthen

Plate 8, figures 19, 20, 25

Naticopsis littonana var. genevievensis Meek and

Worthen, 1867, p. 268. 

Naticopsis (Naticopsis) genevievensis Gordon and

Yochelson, 1982a, p. 217, 218, text-fig. 1A-M.

Discussion. A second species of Naticopsis in the 

Chainman differs in shape from N. (Naticopsis) confusionensis in being slightly less well rounded and in 

having the final whorl attach to the penultimate whorl 

a short distance above the periphery; specimens also 

reach twice the size of N. (N.) confusionensis. These 

differences are relatively minor and might be attributed to individual variation or preservation, except 

for one additional feature. Growth lines are somewhat 

more prominent in this species than on the polished 

shell ofN. (N.) confusionensis. Near the suture, these 

growth lines are strengthened into subsutural riblets, 

separated by incised interspaces. So far as can be determined, subsutural ornamentation occurs at all growth 

stages. The shell is moderately thick, being about 

0.8 mm on the upper part of the whorl and twice that 

thickness on the base. The height of an average specimen is about 25 mm.

The ornamentation is similar to that found in AT. (N.) 

suturicompta Yochelson and Dutro, from the Alapah 

Limestone of northern Alaska. In that species, a narrow but distinct flattening of the whorl is present in the 

subsutural region. This nearly flat ramp is absent in 

the Utah specimens. Gordon and Yochelson (1982a) 

showed that American Midcontinent shells of this type, 

which occur in the Goniatites granosus Zone and its 

equivalents, can be referred to N. (Naticopsis) 

genevievensis Meek and Worthen, a previously unillustrated species. The Utah shells in this category are 

similar to N. (N.) genevievensis. However, because our 

specimens come from somewhat younger beds and because none is complete or undistorted, we merely suggest a comparison with Meek and Worthen's species.

The Utah specimens are not well preserved; only 

three show the surface sculpture well. Of these, one is 

partly crushed; the other two figured specimens are an

immature one and a fragment of a mature shell. All 

were collected from the Willow Gap Member of Sadlick 

(1966) near Skunk Spring, Confusion Range.

Figured specimens. USNM 211033, 211034.

Occurrence and number of specimens. USGS collections 15355-PC (1), 15362-PC (1), 15363-PC (1), 

725271-PC (1), 25272 (4), Millard County.

Naticopsis (Naticopsis?) clinovata n. sp.

Plate 8, figures 34-38

Naticopsis (Naticopsis?) n. sp. Gordon and Yochelson,

1983, p. 989, fig. 2G, H.

Diagnosis. Naticopsis having the aperture slightly 

extended in an obliquely outward direction; surface 

with subsutural riblets on early whorls, slightly irregular in the subsutural area and near the aperture of 

larger whorls.

Description. Nucleus and early growth stages not 

known; spire low; more mature whorls moderately well 

rounded, extended downward so that whorl profile approximates a shortened teardrop shape. Sutures not 

impressed; body whorl embracing penultimate whorl 

above periphery. Outer lip strongly inclined about 25° 

from vertical. Inductura thick near central area of inner lip, extending only short distance outside aperture. 

Shell surface relatively smooth, but developing short 

curved subsutural riblets on early whorls and irregular 

roughening of growth lines in more mature stage; irregularities most evident on thin outer shell layer; 

growth lines quite obscure except in mature stage.

Dimensions. The holotype is slightly greater than 

10.2 mm in height and slightly greater than 10.5 mm 

in width. A larger paratype is 15.2 mm in height but is 

partially eroded on one side and on the apex; the 

height/width ratio is about 0.9.

Discussion. This species has the final whorl extended diagonally rather than well rounded as in N. 

(N.) confusionensis and is readily distinguished from 

that taxon. It has subsutural ornament, as in specimens tentatively attributed to N. (N.) genevievensis, 

and differs from that species in its distinctive oblongly 

ovate shape. The Utah paratype (USNM 211035) lacks 

subsutural riblets but seems to have lost the outer shell 

layer in the apical part of the shell.

In its configuration, N. (N.?) clinovata seems closest 

to N. (N.) madisonensis Worthen, but the holotype of 

that latter species is 3 1/2 times the size of our specimen, 

is poorly preserved, locally distorted by crushing, and 

has some of the shell missing, affording little basis for 

comparison. Neither species has a well-rounded whorl 

as in the typical subgenus, but the whorl is not extended enough to warrant assignment to N. (Jedria).

Almost all the specimens are from the Willow Gap 

Member of Sadlick (1966) near Skunk Spring, Confu-
90 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

sion Range; one, described and figured in Gordon and 

Yochelson (1983, p. 989, fig. 2G, H) is from USGS collection 23837-PC in the Diamond Peak Formation, 

White Pine County, Nev.

Types. Holotype USNM 211074; paratypes USNM 

211035, 307505.

Occurrence and number of specimens. USGS collections 15355-PC (1), 25252-PC (1), 25566-PC (14), Millard County.

Subgenus N. (JEDRIA) Yochelson, 1952 

Naticopsis (Jedria?) sp.

Plate 8, figures 9-12, 32, 33

Discussion. A single Naticopsis, from the Skunk 

Spring section, Confusion Range, represents a different 

taxon from those previously described. The body whorl 

is extended downward rather than outward, and the 

specimen is relatively compressed for its height. The 

body whorl shows a suggestion of a swelling on the 

outer whorl face above the periphery. These features 

are all indicative of the subgenus Jedria rather than of 

Naticopsis sensu stricto. Finally, the growth lines near 

the suture are impressed, another character common to 

many species of the subgenus.

The earliest growth stages are not preserved, but at 

least three whorls are present. The whorl enlarges at a 

moderate rate for the genus. The spire is low, the suture distinct. Adjacent to the suture, the upper whorl 

face is inclined downward at an angle of about 15°. The 

juncture with the outer whorl face is rounded but relatively abrupt, and that face is straight for about half its 

length. Just above the periphery, it swells outward, the 

periphery itself being well rounded and continuous 

with the area below it, which approaches the arc of a 

circle in its curvature. The outer lip is steeply prosocline, inclined about 20° from the axis of coiling. The 

inductura is prominent and extends from the juncture 

of lip and shell along the inner surface nearly to the 

base of the aperture. Near the periphery, the inductura 

is thickened and subangular. The shell is smooth except for the prominent incised growth lines on the upper surface.

Figured specimen. USNM 348026.

Occurrence. USGS collection 25563-PC (1), Millard County.

Order MESOGASTROPODA

Discussion. Cox (1960) proposed the order Caenogastropoda for all prosobranch gastropods that were 

not assigned to the Archaeogastropoda. This order was 

used by Knight, Batten, and Yochelson (1960), but it 

has not been accepted by most subsequent workers and 

has found no utility among students of modern-day gastropods. To us, it seems appropriate to drop the concept 

of Caenogastropoda and revert to older assignments. 

Considerable question exists whether the Paleozoic 

forms placed in the mesogastropods are really the ancestors for these predominantly late Mesozoic to 

Holocene gastropods. Uniting many high-spired gastropods in "*** an admittedly polyphyletic assemblage 

***" (Cox, 1960, p. 259) does not resolve the issue.

Superfamily LOXONEMATACEA 

Family LOXONEMATIDAE

Genus LOXONEMA Phillips, 1841

Discussion. This genus includes high-spired gastropod shells that are commonly fairly large, reaching 

6 to 8 cm in height. Ornament is predominantly collabral, forming a broad, moderately shallow median 

sinus, below which the growth lines generally are 

opisthocline. The genus ranges from the Middle Ordovician to the Late Mississippian. Two small species 

seem to represent this genus in the Chainman Shale. 

American Mississippian species o/" Loxonema. 

difficile Sardeson, 1902

knighti Yochelson, 1962

pikense Hyde, 1953

tenuilineatum (Shumard), 1855 (Chemnitzia)

yandellanum Hall, 1857

Loxonema missouriensis Williams, listed by Yochelson and Saunders (1967, p. 121) among the late Paleozoic species, comes from the Louisiana Limestone of 

Missouri, now considered Late Devonian in age. L. delphicola Hall, a Middle Devonian species, was figured 

by Herrick (1893, pi. 20, fig. 15) from the Lower Mississippian of Ohio. Topotypes of Hall's species are moderately slender and have prominent strongly curved 

growth lines, and slight sulcation below the suture. 

Herrick's drawing depicts a shell having much more 

inflated whorls than typical L. delphicola and no apparent subsutural banding; the growth striae appear 

weaker, more closely spaced, and less curved. Herrick's 

specimen is not conspecific and should be removed from 

the synonymy of Hall's species. Lacking authentic 

specimens of Herrick's material, we prefer not to assign 

it to a species.

Loxonema yandellanum Hall from the Salem Limestone at Spergen Hill, Ind., was transferred to 

Palaeozygopleura by Thein and Nitecki (1974, p. 179). 

This species is characterized by numerous and faint 

collabral riblets or lirae. We have examined more than 

50 topotypes that agree in shape with this species; in 

all, the collabral sculpture is obscure to absent. We 

were unable to determine whether this condition is due 

to solution or abrasion, but many other species in the 

fauna show a similar obscurity of sculpture. We feel
SYSTEMATIC PALEONTOLOGY 91

that because of the pendulent shape of the whorls 

that is, the periphery low on the mature whorl and the 

exceedingly fine axial sculpture this species should 

be left for the present in Loxonema.

Loxonema sp.

Plate 9, figure 37

Discussion. Two specimens from a concretion about 

15 feet (4.6 m) above the limestone marker bed of the 

Chainman Shale in the Granite Mountain measured 

section belong to the genus but are not preserved well 

enough to name formally. The better preserved individual, missing part of the spire, has six whorls and is 

7.5 mm high and 2.4 mm wide. The whorls are well 

rounded, almost moniliform in appearance, with distinct sutures. The shell itself is moderately thick so 

that the steinkern shows a distinct gap between the 

whorls. The area of the periphery is slightly flattened. 

Whorls are ornamented by very fine rounded collabral 

threads, having interspaces two to three times the 

width of the threads. The threads are almost orthocline 

at a deeply impressed suture, swing backward to form 

a shallow, broad, bow-shaped sinus over the rounded 

periphery, and become opisthocline over the basal part 

of the whorl. The smooth columella is slightly inclined 

toward the aperture; the aperture is subcircular.

This shell can be distinguished from most other highspired gastropods in the Chainman Shale by the absence of riblets of any kind, the only sculpture being 

that of delicate collabral lirae. It differs from Loxonema? sp. in having more evenly curved and coarser 

collabral lirae, about 15 in the space of 1 mm where the 

whorl is about 2 mm wide.

Figured specimen. USNM 348027.

Occurrence and number of specimens. USGS collection 25558-PC (2), Juab County.

Loxonema? sp.

Plate 9, figure 36

Discussion. This record is based upon specimens 

from the lower part of the Cravenoceras hesperium Ammonoid Zone, associated with Lunulazona utahensis n. 

sp. in the Bishop Springs anticline on the eastern side 

of the Foote Range. Only one specimen retains the shell 

and shows surface sculpture. It is a small shell of six 

whorls, 5.0 mm high and 1.8 mm wide, the tip of the 

spire broken off. Whorls are well rounded and slightly 

inclined, the sutures deeply impressed. Sculpture consists of exceedingly fine rounded collabral lirae, spaced 

somewhat irregularly; interspaces of similar width to 

lirae; 22 of these lirae occur in the space of I mm on the 

final whorl. These growth lirae are prosocline at an 

angle of about 30° near the suture and form a moderately deep rounded sinus centering about one-third of 

the distance from suture to suture and just above the 

periphery of the whorl; on the lower half of the whorl, 

the lirae are opisthocline and relatively straight.

This species is distinguished by its asymmetrically 

curved opisthocyrt collabral lirae. It can be confused 

only with Loxonema sp., which occurs four ammonoid 

zones lower.

Figured specimen. USNM 348025.

Occurrence and number of specimens. USGS collection 25260-PC (4), Millard County.

Family PSEUDOZYGOPLEURIDAE 

Genus PSEUDOZYGOPLEURA Knight, 1930

Discussion. This genus includes collabrally ribbed, 

anomphalous, high-spired gastropods having a shallow 

labral sinus and pseudozygopleurid nucleus of 4 to 4 V2 

whorls, the last two bearing tiny curved to sinuous 

axial riblets, which are markedly more delicate than 

those on the postnuclear whorls that immediately follow. Because nuclear whorls of late Paleozoic gastropods are rarely preserved and, if preserved, are generally abraded, uncertainty exists about which 

American Mississippian species belong in this genus. 

Indeed, which genera should be included in the Pseudozygopleuridae is uncertain.

Horny (1954) proposed the genus Palaeozygopleura 

for similar high-spired gastropods having a nucleus of 

2 to 2 V2 smooth whorls; he proposed the family 

Palaeozygopleuridae to contain this and allied genera. 

Horny's genus was based upon Early Devonian gastropods from Czechoslovakia, but he included in it some 

early Carboniferous species from the British Isles. 

Prior to this paper, no paleontologist recognized a pseudozygopleurid nucleus in an American Mississippian 

species. Thein and Nitecki (1974, p. 179-184), however, placed most of the known Late Mississippian species in Palaeozygopleura, describing this sort of nuclear 

whorl in P. venusta Thein and Nitecki and P. welleri 

Thein and Nitecki and suggesting that the same sort of 

nucleus occurs also in Loxonema wortheni S. Weller. 

We examined well-preserved topotype specimens of L. 

wortheni from the Ste. Genevieve Limestone at Waterloo, 111., in the USGS collection and agree that this 

species probably belongs in Palaeozygopleura, along 

with P. venusta and P. welleri.

Subgenus P. (PSEUDOZYGOPLEURA) Knight, 1930

Discussion. So far, the only western species that 

certainly belongs in this subgenus by virtue of having 

a pseudozygopleurid nucleus is Pseudozygopleura 

(Pseudozygopleura) repenningi n. sp., described below 

from the Chainman Shale in the Burbank Hills, Utah.
92 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

We place two other species from the same formation in 

the same subgenus but with question. So far no specimens of these two have been found that have the nuclear whorls preserved.

Pseudozygopleura (Pseudozygopleura) repenningi n. sp.

Plate 9, figure 1

Diagnosis. Small, very high spired gastropod having pseudozygopleurid nuclear whorls; postnuclear 

whorls ornamented by fairly straight, thick, nearly orthocline ribs.

Description. Nucleus of slightly more than four 

whorls, initial part smooth, last two whorls ornamented by tiny, fairly straight to opisthocyrt axial 

riblets. Collabral ornamentation developing abruptly 

on postjuvenile whorls and remaining essentially constant at all later stages. Apical angle of mature shell 

approximately 15°, slightly greater in early stages. Suture distinct, not impressed. Whorl profile almost flat, 

slightly inflated between sutures; periphery obscure, 

very low on whorl; basal whorl surface flattened, 

though not known in detail. Umbilical condition unknown.

Shell ornamented by prominent thick ribs, nearly 

vertical and straight across most of whorls, but appearing faintly sigmoidal at full maturity; approximately 

16 ribs per whorl, spacing and number remaining fairly 

constant so that individual ribs appear aligned in 

ridges extending along length of the shell; ribs reaching almost from suture to suture, relatively constant in 

height throughout length of each whorl, steeply 

opisthocline to almost orthocline, except in most mature stage when upper part of ribs is flatter and wider. 

Interspaces approximately \ llz times as wide as adjacent ribs. Growth lines unknown.

Discussion. This description is based on a unique 

specimen from a bed at or near the top of the Cravenoceras kesperium Zone in the Burbank Hills. Although 

this shell preserves the nuclear whorls, it lacks some of 

the later whorls, and the aperture is slightly distorted 

by compression; the number of whorls, including the 

nuclear ones is 11. The specimen is 7 mm long and 

2.2 mm wide.

Although the tiny axial riblets on the nucleus of this 

species do not appear sinuous like those in P. (P .) semicostata (Meek), the type species of Pseudozygopleura, 

this nucleus is certainly of the pseudozygopleurid type. 

Several American Pennsylvanian species referred to 

this subgenus seem similar to our shell. The wide, relatively straight, elongate ribs distinguish this species 

from those referred to Loxonema, for in that genus the 

ribs are shallower, more closely spaced, and become 

increasingly arcuate with growth.

Type.-Holotype USNM 211044. 

Occurrence. USGS collection 17209-PC, Millard 

County.

Pseudozygopleura (Pseudozygopleura?) lauta n. sp.

Plate 9, figures 6, 7

Diagnosis. Very high spired gastropods having 

sloping, asymmetrically convex whorls, ornamented by 

closely spaced, slightly arcuate costae.

Description. Shell high spired, apical angle nearly 

20°. Nucleus and early whorls unknown. Whorl profile 

inflated, asymmetrically convex, flat adjacent to suture 

and inclined strongly downward for about one-eighth of 

total length, then curving gradually outward, following a gentle arc, degree of curvature increasing toward 

periphery. Periphery low on whorl, about two-thirds of 

distance below suture; whorl profile more strongly 

curved below periphery, then curving more abruptly 

into flattened anomphalous base. Suture distinct; body 

whorl embracing penultimate whorl just above curvature into base. Upper part of columellar lip straight; 

other apertural details unknown.

Growth lines forming extremely shallow sinus, having its upper and lower ends parallel to shell axis and 

its greatest depth across periphery. Growth lines obscure, except in maturity, and generally replaced by 

collabral costae. Costae low, rounded, asymmetrical in 

cross section, being steeper adapically, and closely 

spaced, having intercostal spaces approximately as 

wide as costae. Costae weak near suture, prominent 

over convex part of whorl, continuing strongly almost 

to base. More than 35 costae occur at maturity.

Dimensions. The holotype, an incomplete apical 

part of shell, is 8.5 mm high and 3.8 mm wide. Fragmental paratypes indicate that shells of this species 

may have exceeded 35 mm in height.

Discussion. This species is based on one wellpreserved, though incomplete, specimen from the Burbank Hills and four partly crushed paratypes from the 

Confusion Range. On several paratypes, the costae are 

less prominent than those on the holotype at comparable growth stages. This difference might suggest that 

the Confusion Range specimens belong to different species from that of the holotype, but close examination of 

details of whorl profile, apical angle, and trend of 

costae on the Confusion Range specimens shows these 

features to be identical with those on the holotype. Perhaps on the paratypes, a thin outer shell layer, on 

which the costae were sharper, has been removed. 

However, even allowing for this difference in preservation of inner and outer shell layers, the larger specimens show more obscure costae. We conclude that this 

is an example of obsolescence of the costae on the later
SYSTEMATIC PALEONTOLOGY

whorls, a relatively common feature on some mature 

pseudozygopleurids.

Although, in the absence of nuclear and other early 

whorls, we cannot assign this species to this genus with 

certainty, its occurrence in the same stratigraphic unit 

as P. (Pseudozygopleura} repenningi n. sp. indicates 

that an assignment to this same subgenus is reasonable.

Types. Holotype USNM 211042; paratypes USNM 

211043.

Occurrence and number of specimens. USGS collections 15364-PC (4), 17208-PC (1), Millard County.

Pseudozygopleura (Pseudozygopleura)? sp.

Plate 9, figure 18

Discussion. A single silicified specimen from a bed 

in the upper part of the Chainman Shale in the section 

at Granite Mountain is related to the two preceding 

species. Like the type of P. (P.)? lauta n. sp., it lacks the 

nucleus and at least part of the first postnuclear 

whorls. This incomplete shell is slender, 7.1 mm high, 

and 2.8 mm wide. Its sloping whorls are gently convex, 

the periphery two-thirds to three-fourths of the distance from the suture to the following suture. The surface of the shell is ornamented by fairly high, narrowly 

rounded axial ribs, of which 18 are on the last whorl. 

These ribs are gently opisthocyrt and slightly 

opisthocline. Interspaces are subequal to the ribs and 

seem to be V-shaped. The ribs reach the area covered 

by the next suture but die out rather quickly on the 

smooth imperforate base. The initial part of the columella is fairly straight. The anterior part of the base 

and outer lip is broken off.

This species differs from P. (P.)? lauta n. sp. in being 

more slender and in having fewer and coarser ribs.

Figured specimen. 348030.

Occurrence. USGS collection 25252-PC, Juab 

County.

Subgenus P. (STEPHANOZYGA) Knight, 1930

Discussion. Members of this subgenus have larger, 

broader shells and a wider apical angle than does P. 

(pseudozygopleura). The collabral lirae are weak on the 

upper whorl surface, but rather strong nodes ornament 

the periphery of the slightly overhanging whorls and 

extend onto the lower whorl surface.

Thein and Nitecki (1974, p. 185, 186, figs. 82, 83) 

figured and briefly described two species from the Golconda Limestone of Kentucky as P. (Stephanozyga) sp. 

indet. 1 and 2. The first species resembles slightly the 

shell described below from the Chainman Shale, but

the specimen is too poorly preserved to compare in detail. We follow Knight (1930, p. 62) in regarding this 

taxon as a subgenus of Pseudozygopleura. <

Pseudozygopleura (Stephanozyga) claviger n. sp.

Plate 9, figures 2, 3

Diagnosis. High-spired gastropod ornamented by 

unusually large riblike nodes that are slightly asymmetrical in vertical profile and occur 10 to the whorl.

Description. Shell high-spired; protoconch, and 

early whorls unknown; apical angle nearly 20°. Body 

whorl embracing below periphery and immediately below curved junction of outer and basal surfaces of 

penultimate whorl, so that profile of shell is sinuate 

rather than convex. Suture obscure, slightly wavy, located just below row of nodes on outer whorl face. 

Whorl profile below suture and between nodes flattened and nearly vertical for about one-third of distance down whorl side, then gradually bending outward to gently inflated periphery located about 

two-thirds of distance downside of whorl, and below 

periphery, curving gradually inward. Junction of outer 

and basal surfaces of whorl abruptly and strongly 

arched; basal surface inclined about 15° from horizontal; other details of base unknown.

Ornament of prominent axially elongate nodes on 

outer whorl face, commonly 10 per whorl, more or less 

aligned in vertical rows from whorl to whorl. Individual nodes slightly asymmetrical in outline, beginning 

about one-third of distance below suture, ending just 

above junction with basal surface, expanding uniformly so that maximum width is at or just above periphery; interspaces in this zone less than half the 

width of nodes; greatest height of nodes in plane of 

maximum whorl width; nodes symmetrically convex in 

horizontal section, tapering more abruptly downward 

than upward.

Discussion. This species is based upon two incomplete specimens, each having about four whorls. These 

specimens are from the Willow Gap Member of Sadlick 

(1966), in the Skunk Spring measured section, Confusion Range. The holotype is 14 mm long and has a 

maximum diameter of 6.7 mm; in the paratype, these 

dimensions are 16 mm and 7.7 mm respectively. A 

poorly preserved specimen, overgrown by a bryozoan, 

collected from a different bed in the same member is 

referred to this species with question.

The nodose character of the ornamentation readily 

distinguishes P.(S.) claviger from all other high-spired 

gastropods in the fauna. Thein and Nitecki (1974, 

p. 184-186) described specimens of P. (Stephanozyga) 

from the Golconda Limestone of Chesterian age near 

Claxton, Ky. Another lot of specimens in the collections
94 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

of the USNM, from mid-Chesterian rocks near Scottsburg, Ky., resembles our western species in having 10 

to 12 large nodes ornamenting each whorl. These specimens are rather crudely silicified and weathered; this 

difference in preservation from our material makes 

specific comparison uncertain. Also in the USNM collection is another specimen of this subgenus, collected 

by Ulrich from the Ste. Genevieve Limestone near 

Princeton, Ky.; this is a further downward extension of 

the range. In the USGS collection are specimens collected by Ulrich from the Ste. Genevieve Limestone, 2 

miles (3.2 km) south of Ste. Genevieve, Mo.

This subgenus P. (Stephanozyga) is not common; 

species assigned to it constitute a highly specialized 

group perhaps derived from P. (Pseudozygopleura) or a 

common ancestor. In particular, it is easy to envision 

an ancestor similar to the thick-ribbed P. (P.) repenningi that could have given rise to both that species 

and the nodose P. (S.) claviger by only a minor modification of the ornamentation.

Types. Holotype USNM 211045; paratype USNM 

211046.

Occurrence and number of specimens. USGS collections 15355-PC (2), 715375-PC (1), Millard County.

Superfamily SUBULITACEA

Family SUBULITIDAE 

Subfamily SUBULITINAE

Genus BULIMORPHA Whitfield, 1882

Discussion. This genus includes fusiform subulitids having slender shells with gently convex smooth 

whorls, the last whorl accounting for more than half 

the shell height; broken shells show a siphonal fold. 

American Mississippian species of Bulimorpha. 

bulimiformis (Hall), 1857 (Bulimella)

elegans Girty, 1927

elongata (Hall), 1857 (Bulimella)

minor Thein and Nitecki, 1974

whitfieldi S. Weller, 1916

This genus is poorly understood, and limitations of 

individual variation have not been carefully studied. 

Most species are inadequately known, and no comparison among them seems appropriate.

Bulimorpha sp.

Plate 9, figures 4, 5

Discussion. This species occurs in the basal bed of 

the Willow Gap Limestone Member of Sadlick (1966) in 

the Wallet Gulch measured section, Confusion Range. 

Specimens are coarsely silicified and only fairly well

preserved. The shell is slender, fusiform, consisting of 

at least five whorls; pleural angle 32°. Measurements 

(in mm) of two specimens are, respectively: length 6.5 

(anterior edge of aperture missing) and 6.8 (tip of spire 

missing); length of final whorl 4.1 and 4.6; length of 

spire 2.4 and 2.2 (tip of spire missing); and width 2.7 

and 2.7. The whorls are gently convex, the suture well 

marked but not deeply impressed. The final whorl is 

long, accounting for nearly two-thirds of the length of 

the shell. The aperture is narrowly suboval, pointed 

posteriorly and rounded anteriorly, extending slightly 

more than one-third the length of the shell. Whether a 

siphonal notch is present cannot be determined.

The only previously described western Mississippian 

species of Bulimorpha is B. elegans Girty from beds of 

Meramecian age in Idaho. Girty's species is more than 

twice the size of this one and has a proportionally 

higher spire and shorter aperture. The Utah species is 

more like B. minor Thein and Nitecki from the lower 

part of the Okaw Limestone ("Marigold Oolite") of Illinois, but it is slightly larger and less slender than the 

holotype of B. minor.

Figured specimen. USNM 211072.

Measured specimen. USNM 211073.

Occurrence and number of specimens. USGS collection 25566-PC (2), Millard County.

Subfamily SOLENISCINAE 

Genus IANTHINOPSIS Meek and Worthen, 1866

Discussion. This genus includes species having 

shells of various shapes, from globular to fusiform and 

high spired. The surface is normally smooth but exceptionally bears faint spiral ridges. A siphonal fold commonly is present on the last two whorls but is barely, if 

at all, visible within the aperture and is resorbed in the 

early whorls. The Chainman specimens described below do not show the siphonal fold clearly within the 

aperture.

North American Mississippian species of lanthinopsis. 

gandyensis n. sp.

keyesi (Rowley), 1900 (Macrochilina) 

littonanus (Hall), 1857 (Natica) 

melanoides (Whitfield), 1882 (Polyphemopsis) 

pinguis (Winchell), 1863 (Macrocheilus) 

reticulatus (Hyde), 1953 (Strobeus) 

stinesvillensis (Cumings), 1906 (Macrocheilus) 

subcorpulentus (Whitfield), 1882 (Macrocheilus) 

tantillus (Rowley), 1900 (Macrochilina) 

Like Bulimorpha, this genus and its various species 

are inadequately studied. Additional data on some of
SYSTEMATIC PALEONTOLOGY 95

the species listed may be obtained from Thein and 

Nitecki (1974, p. 192-196).

lanthinopsis gandyensis n. sp.

Plate 9, figures 30-33

Diagnosis. Broad subglobose smooth shells having 

small sharp spire rising above slightly flattened upper 

whorl surface.

Description. Nucleus and early whorls smooth, 

well-rounded; periphery at or below midwhorl in early 

stages but gradually rising with growth; pleural angle 

about 105°. Suture distinct, though not impressed. Mature whorl profile nearly horizontal adjacent to suture, 

gently convex; spire prominent above upper whorl surface; upper surface at its outer edge curving abruptly 

but smoothly into outer whorl face, periphery high on 

mature whorl, below which whorl curves gradually inward, curvature increasing toward base. Columella 

without plications, covered with thin inductura extending short distance outside aperture, lower part of aperture unknown, possibly protruding in short siphon. 

Surface smooth; growth lines extremely fine, closely 

spaced, essentially orthocline from suture to below periphery, gradually curving to strongly prosocline.

Dimensions. Holotype and figured paratype have 

heights (incomplete) of 9.5 and 12 mm and widths of 9 

and 10 mm, respectively.

Discussion. The three primary types were collected 

in shale a few feet above the Richardsonites merriami 

bed in the Foote Range. Other specimens are mainly 

steinkerns, and one squashed example is doubtfully 

referred. The lowest occurrence noted is in the upper 

part of the Cravenoceras hesperium Zone.

This extremely low-spired and broad-whorled form 

resembles several common Middle to Late Pennsylvanian species assigned to the genus more than it does 

American Mississippian species. The whorl shape also 

is similar superficially to that of Naticopsis, but the 

rate of whorl expansion is more gradual in lanthinopsis.

Many of the Mississippian species currently assigned 

to lanthinopsis may be incorrectly placed. Among those 

that probably belong in this genus, both /. littonanus 

(Hall), from the St. Louis Limestone of Indiana, and /. 

reticulatus (Hyde), from the Logan Formation at 

Sciotoville, Ohio, are more slender than the Chainman 

form.

Types. Holotype USNM 211047; paratypes USNM 

211048, 211049.

Occurrence and number of specimens. USGS collections 717209-PC (1), 17219-PC (1), 17310-PC (1), 

22883-PC (3), Millard County.

lanthinopsis sp. A

Plate 9, figures 26, 27

Discussion. Another species of lanthinopsis occurs 

at a locality in the Foote Range associated with 

Richardsonites merriami. It is readily distinguished 

from /. gandyensis by its narrowly bulliform shape. The 

specimens are mainly steinkerns with small fragments 

of thin shell adhering to them and are thus inadequate 

for assigning a formal name. The largest specimen, is 

figured and measures 6.6 mm in height and 4.5 mm in 

width and probably has about five postnuclear whorls, 

the spire occupying a little less than half the height; 

the pleural angle is approximately 55°. A simple orthostrophic nucleus is present but not clearly delimited 

from the more mature whorls.

The whorl profile is smoothly curved and slightly 

asymmetrical so that the upper part is shorter and 

more strongly arched than the lower part; the periphery is slightly above midwhorl. The whorls embrace 

below the periphery so that the sutural area is slightly 

sunken. A small inductura seems to be present near the 

upper part of the aperture. The columella appears 

straight; a short siphon is present at the base of the 

aperture. Growth lines are not visible, and no further 

apertural details are available.

The absence of an obvious columellar plication differentiates this species from specimens in the fauna assigned to Soleniscus.

Figured specimen. USNM 211050.

Occurrence and number of specimens. USGS collection 15370-PC (5), Millard County.

lanthinopsis sp. B

Plate 8, figures 30, 31

Discussion. An incomplete specimen of lanthinopsis was collected in the Foote Range, weathering out 

just above a bed of narrow anthracospirifers that is 

some distance above the Richardsonites merriami bed, 

in what B. L. Mamet (written commun., 1975) regards 

as the lower part of Foraminifer Zone 19. The shell is 

broadly bulliform, the nucleus and part of the first postnuclear whorl missing, 4-1/3 whorls remaining, the 

final half whorl and lower part of outer lip broken off. 

It is 13.1 mm long and 11.5 mm in diameter, probably 

lacking a little more than a millimeter of its original 

length at this diameter. The periphery remains at or 

below midwhorl during growth, and the pleural angle 

is 77°. The mature whorl meets the preceding whorl at 

an angle of about 65° to the shell axis, forming a faint 

narrow sloping flat zone bordered by a similarly narrow zone of greatest curvature, below which the whorl
96 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

is gently convex in profile; the periphery is a little 

below midwhorl. The columella shows no plications 

and is covered by a thin inductura, which probably did 

not extend much beyond the aperture; the lower part of 

the columella is missing. The early whorls (2 Va) are 

ornamented by closely spaced collabral lirae, nearly 

orthocline at the suture and curving to fairly strongly 

prosocline as they cross the whorl; the more mature two 

whorls are smooth.

Another specimen, slightly less well preserved, was 

collected in the Burbank Hills. It is referred questionably to this taxon and is illustrated on plate 8, figures 

27 and 28.

This species is distinguished easily from lanthinopsis 

gandyensis n. sp. by its more regular growth pattern, 

narrower pleural angle, lower position of the periphery 

on the later whorls, and the presence of collabral lirae 

on the early whorls. It has a broader shell than 

lanthinopsis sp. A.

Figured specimens. USNM 211053, 211057.

Occurrence. USGS collection 717208-PC (1), 

25551-PC (1), Millard County.

lanthinopsis? sp.

Plate 9, figures 20, 21

Discussion. A single specimen of subulitacean was 

found in the Lunulazona nodomarginata assemblage in 

the upper part of the Goniatites americanus Zone of late 

Meramecian age in the Granite Mountain measured 

section. It is a small subglobose species having about 

four whorls, the spire occupying three-tenths the 

height of the shell; the pleural angle is about 80°. The 

nucleus is not preserved; the early whorls are well 

rounded, the suture a little above the periphery; the 

final whorl meets the penultimate whorl at the periphery, the suture lying in the obtusely angular depression 

where the adjacent whorls meet. Below the suture, 

where the slope of the upper whorl surface is approximately 40° to the axis of coiling, the mature whorl 

profile is rather evenly convex, the periphery being 

near midwhorl; this curvature continues on to the 

lower part of the whorl but is slightly less pronounced, 

then increases to round into the base. The columella 

has no visible plications or inductura, and no siphon 

seems to be present. The shell surface is smooth; 

growth lines are exceedingly fine, aligned orthocline to 

a little below the periphery, where they die out; they 

are slightly more pronounced subadjacent to the suture. The specimen is 5.0 mm in height and 4.3 mm in 

maximum width.

This species has a much smaller and more delicate 

shell than lanthinopsis gandyensis n. sp. and differs 

also in being higher than wide and in having a proportionately longer spire and smaller pleural angle. The 

species that occurs higher in the section, which we have 

identified as lanthinopsis sp., differs from this shell in 

its more slender bulliform shape, longer spire, and 

smaller pleural angle.

Figured specimen. USNM 211051.

Occurrence. USGS collection 17018-PC, Juab 

County.

Genus SOLENISCUS Meek and Worthen, 1861

Discussion. This genus is distinguished from 

lanthinopsis by its generally more slender fusiform 

shell and the presence of a small siphonal notch visible 

within the aperture. A siphonal canal occurs on the 

columella within the shell and a siphonal fold above it. 

The shell surface is smooth.

North American Mississippian species of Soleniscus. 

glaber Cumings, 1906

Elias (1958, p. 21, pi. 2, figs. 8-10) described and 

figured as a variety of Soleniscus (Macrocheilus) regularis (Cox) specimens from the Redoak Hollow Formation of southern Oklahoma. Cox's species, described as 

Loxonema regularis Cox from the "Coal Measures" of 

Kentucky, was transferred to lanthinopsis by Hoare 

(1961, p. 192, 193). Elias's shells may belong in more 

than one taxon, and none of them approach the slender 

shape of/, regularis (Cox); they certainly are not conspecific with Cox's species. Whether or not they are 

congeneric with Cox's species cannot be determined at 

present.

Easton (1962, p. 101, pi. 13, fig. 19) described and 

figured as Soleniscus sp. indet. a silicified specimen 

from the Heath Formation of south-central Montana. 

Another unnamed species was described and illustrated from the lower part of the Okaw Limestone 

("Marigold Oolite") in Illinois by Thein and Nitecki 

(1974, p. 197-198). One poorly preserved Chainman 

specimen from the Skunk Spring-Willow Gap measured section in USGS collection 25271-PC is listed in 

this report as Soleniscus? sp.

Soleniscus sp. A

Plate 9, figure 35

Discussion. One small silicified specimen of five 

whorls preserves much of the aperture and has a distinct siphonal notch; the upper half of the columellar 

lip is reflexed to form a prominent fold. This shell has 

the highest spire of all the presumed neogastropods in 

the Chainman fauna, the spire accounting for almost 

half its length of 6.5 mm. The shell is partly crushed, 

which precludes providing a formal name for this 

taxon. The whorl profile is gently arched between shal-
SYSTEMATIC PALEONTOLOGY 97

low sutures; the apical angle is relatively small, probably less than 20°.

Although Soleniscus, as currently interpreted, is uncommon in beds of Mississippian age, and, although the 

relatively narrow width of this shell is not particularly 

characteristic of the genus, the details of the aperture 

make any other placement unlikely. It does not belong 

in the superficially similar genus Bulimorpha, which 

has a much more elongate body whorl and has the columellar fold hidden when the aperture is complete. 

Soleniscus glaber Cumings, from the Salem Limestone 

of Indiana, is comparable in size with this specimen, 

but wider.

This taxon in external shape is most similar to the 

totally unrelated genus Anematina. It can be distinguished from the common Mississippian species A. 

proutana (Hall) from the Salem Limestone of Indiana 

by its less well rounded whorls as well as by its basal 

siphonal notch.

This Chainman specimen comes from the upper part 

of the Cravenoceras hesperium Zone (middle E2) in the 

Burbank Hills.

Figured specimen. USNM 211052.

Occurrence. USGS collection 17188-PC, Millard 

County.

Soleniscus sp. B

Plate 9, figure 34

Discussion. A second species of Soleniscus in the 

Chainman Shale, from the Conger Mountain section, 

Confusion Range, is larger than S. sp. A and has a 

bulliform shape. The earliest whorls are not known; the 

younger and more mature whorls do not show any ontogenetic change in the position of the periphery, so that 

the apical angle remains fairly constant at about 70°. 

The final whorl embraces the penultimate whorl 

slightly below the periphery, so that the obscure suture 

lies at the bottom of a shallow trough. The whorl profile 

is moderately elongate and maintains an essentially 

uniform curvature from suture to base. A single fold is 

present low on the columella; no evidence exists for the 

presence of a siphon. Growth lines are orthocline and 

are closely spaced on the smooth shell surface. A small 

inductura probably is present, near the upper part of 

the columellar lip. The most complete specimen is 

15.5 mm long and 10.1 mm wide; it lacks the tip of the 

apex, which probably would add another 1 mm to the 

length.

This species can be confused with only one other 

Chainman gastropod, the bulliform shell described as 

lanthinopsis sp. A, which is less than half the size of 

Soleniscus sp. B and seems to be without a columellar 

fold in the aperture.

Figured specimen. USNM 211054.

Occurrence and number of specimens. USGS collections 15356-PC (1), 17021-PC (2), 17208-PC (1), 

22880-PC (2), 25274-PC (2), 725550-PC (1), Millard 

County.

Family MEEKOSPIRIDAE 

Genus MEEKOSPIRA Ulrich in Ulrich and Scofield, 1897

Discussion. This genus includes high-spired subulitaceans having shells of approximately 10 whorls, the 

spire longer than the final whorl. The shell is narrowly 

conical and its surface smooth and polished. No columellar fold nor anterior notch are present.

North American Mississippian species of 

Meekospira. 

bambooformis Thein and Nitecki, 1974

batteni Thein and Nitecki, 1974

evansvillensis Thein and Nitecki, 1974

minuta Weller, 1916

mississippiensis Thein and Nitecki, 1974

Meekospira sp.

Plate 9, figure 10

Discussion. This species is represented in the 

Chainman fauna by eight incomplete specimens. They 

are moderately slender, having apical angles of approximately 17°; the whorls are moderately well arched. 

Details of the aperture are not available, and the specimens are too poorly preserved to support a name for 

this species.

The most similar described American Mississippian 

species, M. minuta Weller from the Ste. Genevieve 

Limestone of Illinois, is readily distinguished. It has a 

smaller shell, a narrower apical angle, and slightly 

flattened whorls.

Other shells having fairly high spires are included 

currently in lanthinopsis. One of these shells, described 

originally as Macrochilina worthenanus Miller from 

the St. Louis Limestone in Illinois, is similar to 

Meekospira in configuration. It differs from the Chainman species in being slightly wider. Two other species, 

lanthinopsis subcorpulentus (Whitfield) from the 

Maxville Limestone of Ohio and /. keyesi (Rowley) from 

the lower part of the Burlington Limestone of Missouri, 

seem to be intermediate between Meekospira and Soleniscus in having strongly inflated whorls. This feature distinguishes them from the Chainman 

Meekospira. All four of these named species require 

further study before they can be assigned to the genus 

with any degree of confidence.

Figured specimen. USNM 211055.
98 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Occurrence and number of specimens. USGS collections 25252-PC (5), Juab County; 25274-PC (3), Millard County.

Meekospira? sp.

Plate 9, figures 8, 9

Discussion. A presumably smooth but coarsely silicified high-spired gastropod is referred with some question to Meekospira. Prior to this present study, it would 

have been assigned to Meekospira without hesitation, 

but the presence in the Chainman Shale of a similar 

shell form (Bellazona) bearing a selenizone and, therefore, obviously belonging in a different superfamily 

creates greater uncertainty in assignment of poorly 

preserved specimens of high-spired gastropods.

The shell, from the basal bed of the Willow Gap 

Limestone Member of Sadlick (1966) in the Wallet 

Gulch measured section, consists of approximately four 

whorls; part of the apex and the front edge of the aperture are missing. The remaining part of the shell measures 16.6 mm parallel to the axis of coiling. Sutures 

are fairly distinct but not channeled, and the whorls 

are gently convex. The pleural (apical) angle is 26°. The 

aperture is teardrop shaped, having a curved and thickened inner lip, which suggests that the columella is 

slightly twisted.

In general appearance, this form most closely resembles another Chainman species, Bellazona bella (Walcott) and could easily be mistaken for it. It differs most 

obviously in the curved and thickened inner lip. In B. 

bella and B. polita, the inner lip is approximately 

straight. B. bella is limited to the upper part of the 

Goniatites americanus Zone (Mamet Foraminifer Zone 

16i), and B. polita, to the Goniatites granosus Zone 

(Mamet Foraminifer Zone 16s). Meekospira? sp. occurs 

several hundred feet and two ammonoid zones higher, 

in the Cravenoceras hesperium Zone (Mamet Foraminifer Zone 18).

On the basis of the single specimen at hand, the similarity of the curved inner lip to some other species of 

Meekospira prompts this generic assignment, although 

Meekospira? sp. might have a selenizone.

Figured specimen. USNM 211056.

Occurrence. USGS collection 25566-PC, Millard 

County.

Subclass OPISTHOBRANCHIA 

Order and Family UNKNOWN

Discussion. In a review of Paleozoic genera, Kollmann and Yochelson (1976) concluded that Girtyspira 

could be assigned to the opisthobranchs, partly because 

of the presence of a flattened subsutural ramp. They

did not propose any classification to accommodate the 

few Paleozoic genera assigned to this subclass; 

Girtyspira previously has been considered a subulitacean allied to Meekospira. Our material adds little 

new data and, although we accept assignment of 

Girtyspira to the opisthobranchs, we cannot refine the 

concept further.

Genus GIRTYSPIRA Knight, 1936

Discussion. This genus includes small fusiform 

shells having a spire of moderate height marked by a 

narrow subsutural ramp. The height of the final whorl 

is notably greater than that of the spire. The aperture 

is pyriform, and the columellar lip arcuate and without 

a fold.

American Mississippian species of Girtyspira. 

canaliculata (Hall), 1857 (Bulimella) 

circumsecta n. sp. 

pygmaea (S. Weller), 1916 (Solenospira)

Girtyspira circumsecta n. sp.

Plate 9, figures 28, 29

Diagnosis. Small fusiform gastropod having prominent ramp; outer lip rather markedly prosocyrt.

Description. Protoconch unknown, whorls expanding at relatively slow rate so that at least four occur on 

fairly small shell. Sutures distinct; whorl embracing 

previous one a short distance below ill-defined periphery. Upper whorl surface forming prominent narrow 

ramp, nearly horizontal to axis of coiling except at 

outer edge, which forms abrupt rounded juncture with 

outer whorl face; outer whorl face broadly arched, having approximately uniform curvature from below ramp 

to beginning of basal lip; periphery below midwhorl. 

Growth lines forming 30° angle with suture, strongly 

opisthocline crossing ramp, but curving more strongly 

downward at juncture of ramp and outer face, continuing opisthocline at high angle to below periphery, then 

arching to steeply prosocline on lower part of shell. 

Base anomphalous; inner lip straight. Shell thin, ornamented only by faint, closely but irregularly spaced 

growth lines.

Discussion. This new species, specimens of which 

were found in the Foote Range, differs from Girtyspira 

canaliculata (Hall) in having a lower spire and a 

slightly less elongate whorl. The specimen illustrated 

by Thein and Nitecki (1974, p. 218, fig. 98) is a 

steinkern and could as well belong to this species as to 

the slightly older form from the SaJem Limestone.

Types. Holotype, USNM 348028; paratypes USNM 

348029.

Occurrence and number of specimens. USGS collection 25271-PC (8), Millard County.
REGISTER OF LOCALITIES 99

Order UNCERTAIN 

Superfamily, family, and genus UNKNOWN

Gastropod, gen. and sp. indet.

Plate 9, figure 19

Discussion. This record is based upon high-spired 

specimens etched from limestone blocks from the base 

of the Willow Gap Member of Sadlick (1966). Silicification has obliterated the sculptural detail of the tiny 

shells, so that neither spiral nor collabral lirae can be 

discerned on any of them. Most specimens consist of 

approximately six whorls, ranging from 4.2 to 5.0 mm 

in length and 1.3 to 1.5 mm in greatest width. The 

pleural angle is approximately 9°. The whorls are gently convex, and sutures seem to be fairly deeply impressed.

This species is the smallest and the slenderest highspired gastropod in the Chainman Shale and is distinct 

from the other high-spired forms in this formation. In 

its size and slenderness, it is similar to taxa like 

Donaldina americana Thein and Nitecki from the 

lower part of the Okaw of Illinois. The deterioration 

during diagenesis that these specimens have undergone, however, precludes close comparison with any 

described species.

Figured specimen. USNM 211069.

Occurrence and number of specimens. USGS collections 17214-PC (1), 25566-PC (8), Millard County.

REGISTER OF LOCALITIES

[All measurements originally made in U.S. customary units. 

Metric-conversion table follows the Register.]

14553-PC. Millard County, Conger Mountain Quad. 4.05 mi south 

of Skunk Spring by road, probably in the NE V4 sec. 17, T. 18 S., 

R. 16 W., immediately east of road. Fossils weathering from 25-30 

ft of shale, between two limestone beds. Goniatites granosus zone. 

Collected by M. Gordon, Jr., and E. L. Yochelson, July 17, 1953.

14557-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring section, about 3/8 mi northwest of Skunk 

Spring, and 0.05 mi north of Willow Gap gully mouth. Platy limestone about 25 ft west of road and 0.3 mi north of Skunk Spring; 

approximately 700 ft above base of Chainman Shale. Collected by 

M. Gordon, Jr., and E. L. Yochelson, July 17, 1953.

14558-PC. Millard County, Cowboy Pass SW Quad. Willow Gap 

section, 3/8 mi northwest of Skunk Spring (gully mouth is 0.25 mi 

by road north of Skunk Spring, 1,200 ft west of road and along 

strike 100-300 ft south of gap). Fossils weathering from about 30 ft 

of yellowish earthy limestone, the base of which is about 125 ft 

above a 320-ft section of massive brownish-gray limestone interbedded with shale and shaly limestone. Rhipidomella nevadensis Zone. Collected by M. Gordon, Jr., and E. L. Yochelson, July 17, 

1953.

14559-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Willow Gap section, 3/8 mi northwest of Skunk Spring,

about 700 ft north of gap and about 200 ft west of thick massive 

limestone unit. Same interval as 14558-PC and about 1,000 ft 

farther north along strike from it. Rhipidomella nevadensis Zone. 

Collected by M. Gordon, Jr., and E. L. Yochelson, July 17, 1953. 

15157-PC. Millard County, Richfield 2° Army Map Service sheet. 

Needle Range, northern part, limestone bed roughly 200 yds west 

of road and a short distance south of gully in the NW 1/4 sec. 26, 

T. 25 S., R. 19 W., along which oil company section was measured. 

Third shale ridge west of road. Paracravenoceras barnettense Zone. 

Collected by I. G. Sohn and R. Kopf, Aug. 9, 1954.

15159-PC. Millard County, Richfield 2° AMS sheet. Needle Range, 

northern part, in N V2 sec. 27, T. 25 S., R. 19 W. Detrital limestone 

bed containing Diaphragmus, 3-10 in. thick, at oil-company stake 

#529 in oil-company measured section. Upper part of Chainman 

Shale; approximately 300 ft stratigraphically below base of Ely 

Limestone (according to W. Sadlick). Collected by M. Gordon, Jr., 

and I. G. Sohn, Aug. 9, 1954.

15160-PC. Millard County, Richfield 2° AMS Sheet. Needle Range, 

northern part, same area as 15159-PC, but about 200-300 ft 

southeast across gully. From nodular black shale beds through a 

2-ft interval, about 15 ft stratigraphically below the bed of 15159- 

PC. Upper part of Chainman Shale. Collected by M. Gordon, Jr., 

and I. G. Sohn, Aug. 9, 1954.

15161-PC. Millard County, Richfield 2° AMS sheet. Needle Range, 

northern part, same general area as 15159-PC. From nodular 

limestone, 2-ft interval, 3 ft stratigraphically below bed of 15159- 

PC and roughly 100 ft northwest of 15160-PC. Bed containing 

Richardsonites merriami in upper part of Chainman Shale. Collected by M. Gordon, Jr., Aug. 9, 1954.

15165-PC. Millard County, Burbank Hills Quad. NW 1/4 NE 1/4 

SE 1/4 sec. 35, T. 22 S., R. 18 W., Jensen Wash, Burbank Hills. 

Fossils weathering out from shale with limestone concretions in 

area just east of wash and 0.6 mi by road south of sharp turn out 

of first wash, near faulted face of Joana Limestone. Collecting area 

of ridged high ground. Fossils from about 600-630 ft stratigraphically above the top of the 5-ft limestone marker bed in the Chainman Shale; in middle part of Chainman Shale. Paracravenoceras 

barnettense Zone. Collected by M. Gordon, Jr., B. W. Gordon, I. G. 

Sohn, and R. W. Kopf, Aug. 11, 1954.

15166-PC. Millard County, Burbank Hills Quad. Jensen Wash, 

same general locality and stratigraphic zone as 15165-PC, but 

south of a gully and a small fault and generally southeast of 

15165-PC along an area 150 yds long, roughly, trending southwest 

across the ridge and gully and truncated at the southwest end by 

the main wash. Paracravenoceras barnettense Zone. Collected by 

M. Gordon, Jr., I. G. Sohn, and R. W. Kopf, Aug. 11, 1954.

15354-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section, probably in N V2 SE V4 

sec. 28, T. 17 S., R. 16 W. Upper cephalopod zone in lower part of 

Chainman Shale, 20 ft below "upper marker" bed at Skunk Spring. 

Collected by R. K. Hose and D. L. Durham, July 17, 1954.

15355-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section of Chainman Shale, unit 9, 

1,268 ft above base of formation. Collected by R. K. Hose and D. L. 

Durham, July 16, 1954.

15356-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section of Chainman Shale, unit 

12, lower half, 1.322-1,338 ft above base of formation. Collected by 

R. K. Hose and D. L. Durham, July 17, 1954.

15358-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section of Chainman Shale, unit 

17, 1,462 ft above base of formation. Collected by R. K. Hose and 

D. L. Durham, July 17, 1954.

15359-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section of Chainman Shale, unit
100 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

17, 1,483 ft above base of formation. Collected by R. K. Hose and 

D. L. Durham, July 17, 1954.

15361-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section of Chainman Shale, unit 

17, 1,499 ft above base of formation. Collected by R. K. Hose and 

D. L. Durham, July 17, 1954.

15362-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section of Chainman Shale, unit 

19, 1,551 ft above base of formation. Collectors, R. K. Hose and 

D. L. Durham, July 17, 1954.

15363-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section of Chainman Shale, unit 

19,1,559 ft above base of formation. Collected by D. L. Durham and 

R. K. Hose, July 17, 1954.

15364-PC. Millard County, Conger Mountain Quad. Confusion 

Range, Wallet Gulch partial measured section of Chainman Shale, 

unit 4, west-northwest of Conger Mountain, in sec. 26 (unmapped), 

T. 18 S., R. 17 W., upper 350 ft of Chainman Shale. Collected by 

R. K. Hose, July 27, 1954.

15365-PC. Millard County, Conger Mountain Quad. Confusion 

Range, Wallet Gulch partial section of the Chainman Shale, unit 

13,2.5 mi west-northwest of Conger Mountain, sec. 26 (unmapped), 

T. 18 S., R. 17 W. Collected by R. K. Hose, July 27, 1954.

15370-PC. Millard County, Gandy NE Quad. Foote Range, nearly 

1 mi southeast of well-known Foote Ranch collecting locality, in 

fractional sec. 31, T. 15 1/2 S., R. 17 W. Measured section 4 mi 

east-northeast of Foote Ranch, from zone constituting units 9-13, 

which is 110-140 ft below the top of the Chainman Shale. Includes 

bed containing Richardsonites merriami. Collected by R. K. Hose, 

Sept. 24, 1954.

15372-PC. Millard County, Gandy NE Quad. Foote Range, approximately in center of SE 1/4 sec. 36, T. 15 S., R. 18 W. Original Foote 

Ranch collecting locality, 30-50 ft below top of Chainman Shale. 

Collected by R. K. Hose and D. L. Durham, Sept. 27, 1954.

15375-PC. Millard County, Cowboy Pass SW Quad. Confusion 

Range, Skunk Spring measured section, unit 19, 1,551 ft above 

base of formation. Collected by R. K. Hose and D. L. Durham, July 

17, 1954.

16959-PC. Millard County, Cowboy Pass NW Quad. West side of 

Chevron Ridge, about 1 mi north of Indian Pass, in sec. 15 (unsurveyed), T. 16 S., R. 17 W. From concretionary bed between two 

quartzite beds in upper part of Chainman Shale. Richardsonites 

merriami Zone. Collected by R. K. Hose, May 22, 1957.

16997-PC. Millard County, Conger Mountain Quad. Confusion 

Range, Wallet Gulch measured section, along slope and to top of 

ridge at south side of Wallet Gulch. Fossils weathering from shale 

and nodular limestone in 20-ft interval immediately below highest 

quartzitic bed in Chainman Shale, 160-180 ft below top of Chainman. Collected by M. Gordon, Jr., and R. K. Hose, May 13, 1957.

17003-PC. Millard County, Cowboy Pass NW Quad. Confusion 

Range, 1,500 ft north of west end of Indian Pass, 4-8 ft below top 

of Chainman Shale. Collected by M. Gordon, Jr., and R. K. Hose, 

May 14, 1957.

17012-PC. Juab County, Granite Mountain Quad. Roughly 500 ft 

north of Granite Mountain measured section. Fossils weathering 

from shale containing reddish-brown sideritic claystone nodules, 

119-132 ft above top of limestone marker bed, Goniatites granosus 

Zone. Collected by M. Gordon, Jr., and R. K. Hose, May 15, 1957.

17015-PC. Juab County, Granite Mountain Quad. Slopes on south 

side of ridge in the NE V4 NE l/4 SW V4 sec. 7 (unsurveyed), 

T. 14 S., R. 16 W., 4,000 ft N. 22° E. of high point on Granite 

Mountain. Fossils weathering from about 20-ft interval of shale. 

Stratigraphically equivalent to 17020-PC. Goniatites granosus 

Zone. Collected by M. Gordon, Jr., and C. L. Repenning, May 16, 

1957.

17018-PC. Juab County, Granite Mountain Quad. 4,650 ft due 

north of high point on Granite Mountain. At cleft through marker 

bed in the SE 1/4 SW 1/4 NW V4 sec. 7 (unsurveyed), T. 14 S., 

R. 16 W. Concretions, 3.5-5 ft above top of marker bed. Goniatites 

americanus Zone. Collected by M. Gordon, Jr., and C. L. Repenning, May 16, 1957.

17020-PC. Juab County, Granite Mountain Quad. 4,350 ft. N. 2° W. 

of high point on Granite Mountain in the NW V4 NW V4 sec. 7 

(unsurveyed), T. 14 S., R. 16 W. Fossils weathering out of 18-ft 

interval of shale containing red sideritic claystone concretions; 

base of shale is 93 ft Stratigraphically above top of marker bed. 

Goniatites granosus Zone. Collected by M. Gordon, Jr., and C. L. 

Repenning, May 16, 1957.

17021-PC. Millard County, Conger Mountain Quad. Confusion 

Range, 1,000 ft south by east from Conger Spring. From Chainman 

Shale containing a few resistant quartzitic siltstone ledges, weathering rusty brown; probably 150-300 ft below top of Chainman 

Shale. Rhipidomella nevadensis Zone. Collected by M. Gordon, Jr., 

C. L. Repenning, and R. K. Hose, May 17, 1957.

17022-PC. Millard County, Gandy SW Quad. 150 ft west of road, 

near southern end of Bishop Springs anticline, on east side of Foote 

Range, in SE V4 NW 1/4 NW 1/4 sec. 20 (unsurveyed), T. 16 S., 

R. 17 W. Collected by M. Gordon, Jr., C. L. Repenning, and R. K. 

Hose, May 19, 1957.

17023-PC. Millard County, Gandy NE Quad. Foote Range, about 

1.5 mi southeast of Foote Ranch locality, in the NE V4 NE 1/4 sec. 6 

(unsurveyed), T. 16 S., R. 17 W. Shale containing Cravenoceras 

hesperium. Collected by M. Gordon, Jr., R. K. Hose, and C. L. 

Repenning, May 19, 1957.

17024-PC. Millard County, Gandy NE Quad. Foote Range, about 

0.9 mi southeast of Foote Ranch collecting locality, near center of 

fractional sec. 31, T. 15 1/2 S., R. 17 W. Same as 15370-PC. 

Richardsonites merriami bed. Collected by M. Gordon, Jr., R. K. 

Hose, and C. L. Repenning, May 19, 1957.

17037-PC. Juab County, Granite Mountain quad. Chainman 

Shale, Granite Mountain measured section. Neoglyphioceras 

cloudi utahense in shale, 55 ft Stratigraphically below base of massive blocky limestone unit. Goniatites granosus Zone. Collected by 

M. Gordon, Jr., May 20, 1957.

17055-PC. Millard County, Burbank Hills Quad. Jensen Wash, 

same locality as 15165-PC in the NE V4 SE 1/4 sec. 35, T. 22 N., 

R. 18 W. Shale containing gastropods and Hematites. Collected by 

M. Gordon, Jr., R. K. Hose, and R. J. Ross, June 6, 1957.

17056-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section. Chainman Shale in the SE V4 SW 1/4 NE 1/4 

NE V4 sec. 35, T. 22 S., R. 18 W.; same as Sadlick and Nielson 

(1963) locality 2-11. Collected by M. Gordon, Jr., R. K. Hose, and 

R. J. Ross, June 6, 1957.

17059-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section. Fossils from upper slope of valley cut in small 

hill in the NW 1/4 NE 1/4 NE V4 sec. 35, T. 22 S., R. 18 W., 90-110 ft 

below top of Chainman Shale. Collected by M. Gordon, Jr., R. J. 

Ross, and R. K. Hose, June 6, 1957.

17087-PC. Juab County, Granite Mountain Quad. Granite Mountain measured section. Unit 18 of section; fossils from top 6-in. 

Taonurus bed, 405 ft above base of Chainman Shale. Top of rock 

bench in the SE 1/4 SE 1/4 NE 1/4 sec. 18 (unsurveyed), T. 14 S., R. 16 

W. Collected by M. Gordon, Jr., and C. L. Repenning, June 12, 

1957.

17088-PC. Juab County, Granite Mountain Quad. Granite Mountain measured section. Unit 19 of section; corals 5-6 ft Stratigraphically above base of unit. Gastropods from float in lower 6 ft of unit, 

405-411 ft above base of Chainman Shale. Collected by M. Gordon, 

Jr., June 12, 1957.
REGISTER OF LOCALITIES 101

17091-PC. Juab County, Granite Mountain Quad. Granite Mountain measured section. Unit 24 of section, a 2-ft-thick argillaceous 

limestone bed, 568 ft above base of Chainman Shale. SW 1/4 SE V4 

NE V4 sec. 18 (unsurveyed), T. 14 S., R. 16 W. Collected by 

M. Gordon, Jr., and C. L. Repenning, June 12, 1957.

17092-PC. Juab County, Granite Mountain Quad. Granite Mountain measured section. Unit 26 of section lower 10 ft, 575-585 ft 

above base of Chainman Shale. Collected by M. Gordon, Jr., and 

C. L. Repenning, June 12, 1957.

17095-PC. Juab County, Granite Mountain Quad. Granite Mountain measured section. 1-ft-thick bed containing silicified brachiopods and gastropods 150 ft above base of unit 33 and 1,051 ft 

above base of Chainman Shale. Collected by M. Gordon, Jr., and 

C. L. Repenning, June 12, 1957.

17098-PC. Juab County, Granite Mountain Quad. Granite Mountain measured section. Base to lower half of unit 36, 1,148-1,153 

ft above base of Chainman Shale. Collected by C. L. Repenning, 

June 12, 1957.

17099-PC. Juab County, Granite Mountain Quad. Granite Mountain measured section. Lower 3 ft of unit 37, 1,158-1,161 ft above 

base of Chainman Shale. Collected by M. Gordon, Jr., and C. L. 

Repenning, June 12, 1957.

17101-PC. Juab County, Granite Mountain Quad. Granite Mountain measured section. Unit 39, 23-23 1/2 ft above base, 1,129 ft 

above base of Chainman Shale. Mostly productoid brachiopods 

from limestone below shaly layer. Collected by M. Gordon, Jr., and 

C. L. Repenning, June 12, 1957.

17104 PC. Juab County, Granite Mountain Quad. Granite Mountain section. Unit 34, large coral bed. Two ridges south of line of 

section and part on ridge 150 ft to south, in the SE V4 SE V4 NW lk 

sec. 18 (unsurveyed), T. 14 S., R. 16 W. Collected by M. Gordon, Jr., 

and C. L. Repenning, June 13, 1957.

17186-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section. Fauna from Hematites -bearing shale unit, from 

east slope of Jensen Wash at bend in wash, 3/5 mi upstream from 

where road enters wash. From unit 27, which is 1,060-1,100 ft 

above base of Chainman Shale, but about 150 ft south of line of 

measured section. Collected by M. Gordon, Jr., and R. Christner, 

Sept. 17, 1957.

17187-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section. Unit 26, large Hematites fauna from 50-ft-thick 

shale interval. On brown hill in middle of large gully, the next one 

north of the broader gully of 17186-PC, in the NE V4 SW 1/4 SE V4 

sec. 35, T. 22 S., R. 18 W. Collected by M. Gordon, Jr., and 

R. Christner, Sept. 17, 1957.

17188-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section. Small tributary of main gully about 600 ft west 

of road. Roughly 800 ft northwest of 17186-PC. Same fauna and 

interval as 17056-PC. Collected by M. Gordon, Jr., and R. Christner, Sept. 17, 1957.

17189-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section. Fossils weathering from slope 100-200 ft southsoutheast of 17188-PC and probably several feet lower in section. 

Collected by M. Gordon, Jr., and R. Christner, Sept. 22, 1957.

17194-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section, unit 25. Same locality as 17187-PC, but from 

nodule-bearing shale 20-25 ft thick at top of knoll within gully, 

directly underlying shale of 17187-PC. Paracravenoceras barnettense Zone. Collected by M. Gordon, Jr., and R. Christner, Sept. 

19, 1957.

17201-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section; 1.5-ft-thick bed 702 ft above base of Chainman 

Shale. Paracravenoceras barnettense Zone. Collected by M. Gordon, 

Jr., and R. Christner, Sept. 20, 1957.

17208-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section; unit 42, a 16-ft-thick fossiliferous nodular shale, 

base of which is 1,623 ft above base of Chainman Shale. Collected 

by M. Gordon, Jr., and R. Christner, Sept. 22, 1957.

17209-PC. Millard County, Burbank Hills Quad. Jensen Wash measured section; offset section of upper part of Chainman Shale where 

road descends south to main wash. Same locality and interval as 

17056-PC, base of which is 1,623 ft above base of Chainman Shale. 

Cravenoceras hesperium Zone. Collected by M. Gordon, Jr., and 

R. Christner, Sept. 23, 1957.

17214-PC. Millard County, Conger Mountain Quad. Wallet Gulch 

measured section; 15-ft-thick limestone, top of which is 181 ft 

stratigraphically below base of lowest quartzite in Wallet Gulch 

Section. This limestone makes a little cliff at crest of ridge. 

Roughly in SW 1/4 NE 1/4 sec. 27, T. 18 S., R. 17 W. About 2 mi west 

of 8,070-ft summit of Conger Mountain. Collected by M. Gordon, 

Jr., Sept. 25, 1957.

17217-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section; offset on north side of Jensen Wash. 56-ft-thick 

shale interval, containing 3-4-ft Michelinia zone, 26 ft below top of 

interval; limestone containing corals 80 ft below top of Chainman 

Shale. Same locality and unit as 17059-PC. Rhipidomella 

nevadensis Zone. Collected by M. Gordon, Jr., and R. Christner, 

Sept. 26, 1957.

17219-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section, NW */4 SW V4 SE V4 sec. 35. Same stratigraphic 

unit as 17188-PC and same general vicinity. Cravenoceras hesperium Zone. Collected by M. Gordon, Jr., and R. Christner, Sept. 

26, 1957.

17250-PC. Millard County, Conger Mountain Quad. Confusion 

Range, 2.4 mi southwest of end of Conger Mountain, 0.1 mi east of 

road. Probably in NE 1/4 sec. 14 (unsurveyed), T. 19 S., R. 17 W. 

Fossils weathering from 30-ft interval of shale, base of which is 

90 ft above top of limestone marker bed. Goniatites granosus Zone. 

Collected by M. Gordon, Jr., and R. Christner, Oct. 7, 1957.

17310-PC. Millard County, Burbank Hills Quad. Fossils weathered out from shale at stake 158 + 20 in oil-company section measured in south Burbank Hills, eastern side. Upper part of Chainman Shale. Cravenoceras hesperium Zone. Collected by J. E. Welsh 

in the late 1950's.

19602-PC. Millard County, Gandy NE Quad. Northeast of Foote 

Range, Bishop Springs anticline area, in the SW 1/4 SE l/4 NE l/4 

sec. 25, T. 15 S., R. 18 W. Middle of Chainman Shale in fault block. 

Upper part of Paracravenoceras barnettense Zone. Collected by 

R. K. Hose, 1959-1960.

19603-PC. Millard County, Gandy NE Quad. East of Foote Range, 

at south end of Bishop Springs anticline in the NE V4 SW V4 SE V4 

sec. 20 (unsurveyed), T. 16 S., R. 17 W. near road.

19604-PC. Millard County, Gandy NE Quad. SW 1/4 SE 1/4 NE 1/4, 

sec. 25, T. 15 S., R. 18 W., Bishop Springs area; basal 10 ft of 

Cravenoceras hesperium Zone. Collected by R. K. Hose, 1959-1960.

20443-PC. Millard County, Gandy NE Quad. Probably near center 

of NW V4 sec. 20, T 16 S., R17 W. East of Foote Range, about 200 ft 

west of road and about 1 3/4 mi south of abandoned oil-well site on 

Bishop Springs anticline. Limestone bed 1 ft thick, 5 ft above top 

of ammonoid bed. Cravenoceras hesperium Zone. Collected by 

M. Gordon, Jr., and R. Rieke, July 26, 1961.

20444-PC. Millard County, Gandy NE Quad. Same locality as collection 20443-PC but from a 1-ft limestone bed stratigraphically 

5.0 ft higher. Cravenoceras hesperium Zone. Collected by M. Gordon, Jr., and R. Rieke, July 26, 1961.

20445-PC. Millard County, Gandy NE Quad. Same general locality 

as 20443-PC; a 6-in. bed 27 ft stratigraphically above the top of the 

ammonoid bed; 15 ft above top of bed of 20445-PC. Cravenoceras
102 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

ftesperium Zone. Collected by M. Gordon, Jr., and R. Rieke, July 26, 

1961.

20446-PC. Millard County, Gandy NE Quad. In SW1/4 SE 1/4 SE 1/4 

sec. 7, T. 16 S., R. 17 W., 430 ft west of curve in road where road 

starts through the Joana Limestone, on west flank of Bishop 

Springs anticline. A zone 20 ft stratigraphically above and 30 ft 

west of 19600-PC. 80 ft above the marker ledge to base of lO^ft 

zone containing Goniatites granosus capped by thin rusty platy 

limestone layer. Collected by M. Gordon, Jr., and R. Rieke, July 26, 

1961.

20448-PC. Millard County, Gandy NE Quad. West edge of SW 1/4 

SE V4 sec. 20, T. 16 S., R. 17 W., east of Foote Range, southern end 

of Bishop Springs anticline. Fossils weathering from soft olive 

shale, 20 ft west of road. Same as 19603-PC. Upper part of 

Paracravenoceras barnettense Zone. Collected by M. Gordon, Jr., 

R. K. Hose, and R. Rieke, July 27, 1961.

20547-PC. Juab County, Granite Mountain SW Quad. Eastern 

slope of Granite Mountain, E 1/2 SE 1/4 NW 1/4 sec. 18, T. 14 S., 

R. 16 W. Fossils from 30 ft of shale and limestone containing large 

Caninia corals, a soft zone below which tributary spurs extend 

eastward. Collected by M. Gordon, Jr., Helen Duncan, 

R. Lewandowski, and R. Rieke, Aug. 11, 1961.

22857-PC. Millard County, Burbank Hills Quad. About 100-200 ft 

east of Jensen Wash; hill in drainage near center SE lk sec. 35, 

T. 22 S., R. 18 W. Paracravenoceras barnettense Zone. Collected by 

M. Gordon, Jr., and Darcy Gloss, Sept. 30, 1962.

22876-PC. Millard County, Gandy NE Quad. Schizophoria bed, 

20 ft of brown shale and overlying 1-ft-thick platy limestone bed 

containing Flexaria, at mouth of wash near center NE lk SE l/4 sec. 

36, T. 15 S., R. 18 W. See measured section of 1957 and earlier. 

Upper part of Chainman Shale. Collected by M. Gordon, Jr., Darcy 

Gloss, and D. Wiese, Oct. 6, 1962.

22880-PC. Millard County, Conger Range NE Quad. Coyote Pass 

area, NW 1/4 SW 1/4 SW 1/4 sec. 7, T. 19 S., R. 17 W. On top and east 

side of a little low ridge, a 0.5-ft limestone bed containing Richardsonites merriami (Youngquist) and associated shale, approximately 190 ft below base of Ely Limestone. Rhipidomella nevadensis Zone. Collected by M. Gordon, Jr., Darcy Gloss, and D. Wiese, 

Oct. 7, 1962.

22883-PC. Millard County, Gandy NW Quad. East slope of Foote 

Range. Fauna of small mollusks weathering from shale on small 

knoll 25-30 ft stratigraphically below massive outcrop of Ely 

Limestone; base showing fault face and breccia, approximately on 

south line, sec. 31, T. 15 l/z S., R. 17 W., about 100 yds south of 

22870-PC and about 50 ft higher in altitude. Collected by 

M. Gordon, Jr., Darcy Closs, and D. Wiese, Oct. 8, 1962.

23846-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section, unit 26. Little shale hill in tributary drainage on 

east side of Jensen Wash about 100 yds from center of wash. Fossils 

weathering out on western slope of hill. Same locality as 17056-PC 

and 17217-PC. Collected by M. Gordon, Jr., and K. R. Moore, 

Aug. 14, 1969.

25249-PC. Juab County, Granite Mountain SW Quad. Base of 

southernmost of four ridges that extend eastward from Granite 

Mountain, about 2,600 ft S. 64° E. of summit, on crest of ridge. 

Fossils from 5-ft interval of medium- to fine-grained gray limestone, weathering orange. Base of bed is 33 ft stratigraphically 

below top of Chainman Shale and 170 ft above base of bed containing Caninia. Collected by M. Gordon, Jr., and K. R. Moore, Aug. 16, 

1973.

25252-PC. Juab County, Granite Mountain SW Quad. Same ridge 

as 25249-PC on lower part of slope above saddle; 12-15-in.-thick 

bed of fossiliferous dark-brownish-gray silty limestone containing 

silicified productoids; 132 ft below base of massive gray coarsegrained crystalline limestone, forming cliff at base of Ely Limestone. Collected by M. Gordon, Jr., and K. R. Moore, Aug. 16,1973. 

25257-PC. Juab County, Granite Mountain SW Quad. Eastern 

slope of Granite Mountain, roughly 1,500 ft east by north of summit, on northernmost of four ridges that extend eastward from 

main part of Granite Mountain, same as original section measured 

in 1957. At narrow saddle above top of limestone bed which is at 

base of Caninia zone. Collected by M. Gordon, Jr., and K. R. Moore, 

Aug. 17, 1973.

25259-PC. Millard County, Gandy NE Quad. SW 1/4 SE 1U sec. 31, 

T. 15 1/2 S., R. 17 W. On northeast slope of hill, roughly 800 ft 

southwest of road and 800 ft north of south line of partial township. 

Agassizocrinus weathering out of shale slope. Upper part of Chainman Shale. Collected by E. L. Yochelson and K. R. Moore, Aug. 18, 

1973.

25260-PC. Millard County, Gandy NE Quad. Cravenoceras bed in 

SE 1/4 NW V4 sec. 20 (unsurveyed), T. 16 S., R. 17 W., on southwest 

side of Bishop Springs anticline at southeast side of Foote Range, 

same locality and bed as 17022-PC. Cravenoceras hesperium Zone. 

Collected by M. Gordon, Jr., E. L. Yochelson, and K. R. Moore, Aug. 

18, 1973.

25261-PC. Millard County, Cowboy Pass SW Quad. Skunk Spring 

section. Fossils weathering from shale containing sideritic concretions, 0.35 mi south of Skunk Spring. Approximately in middle of 

south line of SE 1/4 sec. 27 (unsurveyed), T. 17 S., R. 16 W. Roughly 

350-400 ft above base of Chainman Shale. Goniatites granosus 

Zone. Collected by M. Gordon, Jr., E. L. Yochelson, and K. R. 

Moore, Aug. 18, 1973.

25262-PC. Millard County, Burbank Hills Quad. In SE 1/4 NW 1/4 

sec. 20 (unsurveyed), T. 16 S., R. 17 W., on southwest side of Bishop 

Springs anticline at southeast side of Foote Range; same locality 

and bed as 17022-PC. Cravenoceras hesperium Zone. Collected by 

M. Gordon, Jr., E. L. Yochelson, and K. R. Moore, Aug. 18, 1973.

25263-PC. and 25264-PC. Millard County, Burbank Hills Quad. 

Jensen Wash measured section. Same locality and unit as 17194- 

PC. Collected by M. Gordon, Jr., E. L. Yochelson, and K. R. Moore, 

Aug. 18 and 19, 1973.

25269-PC. Millard County, Conger Mountain Quad. Wallet Gulch, 

50-100 ft above bottom, on east slope roughly 400 ft north of 

right-angle bend, NW 1/4 NE 1/4 sec. 27 (unsurveyed), T. 18 S., 

R. 17 W. Productoids weathering from shale on slope. About 700 ft 

north of section measured in 1954; same unit as 15365-PC. Collected by M. Gordon, Jr., and K. R. Moore, Aug. 20, 1973.

25271-PC. Millard County, Cowboy Pass SW Quad. Section on 

south side of Willow Spring Canyon about 700 ft northwest of 

Skunk Spring. Fossils from bed in soft limestone zone, 85 ft above 

massive limestone at base of Willow Spring Member of Sadlick 

(1966), approximately 110 ft above base of "member." NW lk SE lk 

sec. 28 (unsurveyed), T. 17 S., R. 16 W. Collected by M. Gordon, Jr., 

and K. R. Moore, Aug. 22, 1973.

25272-PC. Millard County, Cowboy Pass SW Quad. Section on 

south side of Willow Spring Canyon, about 800 ft north-northwest 

of Skunk Spring. Fossils from limestone bed in soft zone, 188 ft 

stratigraphically above base of interval collected in 25271-PC, 

50-80 ft above wash. Collected by M. Gordon, Jr., and K. R. Moore, 

Aug. 22, 1973.

25273-PC. Millard County, Gandy NE Quad. Foote Range, west 

side of northeast-trending ridge north of middle of NE V4 NE 1/4 

sec. 6 (from base of interval collected in 25271-PC, 50-80 ft above 

wash. Collected by M. Gordon, Jr., and K. R. Moore, Aug. 22,1973.

25274-PC. Millard County, Gandy NE Quad. Foote Range, west 

side of northeast-trending ridge north of middle of NE lk NE lk 

sec. 6 (unsurveyed), T. 16 S., R. 17 W. From limestone bed about 6 

in. thick and exposed for 4 ft, containing brachiopod and mollusk
REGISTER OF LOCALITIES 103

fauna, on shale slope, about 100 yds south of saddle. Collected by 

M. Gordon, Jr., and K. R. Moore, Aug. 24, 1973.

25275-PC. Millard County, Gandy NE Quad. On west side of little 

embayment of west slope of Foote Range in NW 1/4 NE 1/4 sec. 6 

(unsurveyed), T. 16 S., R. 17 W., about 450 ft N. 60° W. of 25274- 

PC and roughly 25-30 ft higher in altitude; on slope 15-30 ft below 

massive sandstone(?) bed. Collected by K. R. Moore, Aug. 24,1973.

25284-PC. Millard County, Burbank Hills Quad. On north slope of 

east tributary of drainage over area 100 yds square, beginning at 

Jensen Wash. NE 1/4 SW 1/4 SE 1/4 sec. 35, T. 22 S., R. 18 W. Fossils 

weathering from brown shale containing limestone concretions. 

Paracravenoceras barnettense Zone. Collected by M. Gordon, Jr., 

and K. R. Moore, Aug. 26, 1973.

25318-PC. Millard County, Burbank Hills Quad. Upper part of 

slope of south-trending spur of Chainman Shale ridge about 100 

yds S. 30° W. of triangulation marker at top of ridge (not on map); 

SE V4 SW V4 NE V4 sec. 1, T. 22 S., R. 19 W. Altitude about 

6,050-6,090 ft. Spur is of dark-brown shale, darker than rest of 

ground. Cravenoceras hesperium Zone. Collected by M. Gordon, Jr., 

and W. E. McCaslin, Sept. 12, 1974.

25319-PC. Millard County, Burbank Hills Quad. South-southeasttrending ridge, just east of drainage, 100 ft from jeep trail shown 

on map in SW 1/4 SE 1/4 SE 1/4 sec. 29, T. 23 S., R. 18 W. Fossils 

weathering from brown shale at north end of limestone outcrop; 

bed estimated about 100 ft below top of Chainman Shale. Carlinia 

phillipsi beds. Collected by M. Gordon, Jr., and W. E. McCaslin, 

Sept. 13, 1974.

25546-PC. Millard County, Burbank Hills Quad. Jensen Wash 

measured section, unit 13. Fossil from platy silty limestone on 

north bank of wash, SW 1/4 SE 1/4 SE 1/4 sec. 35, T. 22 S., R. 18 W. 

About 1,000 ft east of Jensen Wash. Same locality and unit as 

17201-PC. Paracravenoceras barnettense Zone. Collected by 

M. Gordon, Jr., and W. E. McCaslin, September 15, 1974.

25547-PC. Millard County, Burbank Hills Quad. Jensen Wash section. From Sadlick and Nielsen (1963) locality 2-11 in the SW 1/4 

NE 1/4 NE i/4 sec. 35, T. 22 S., R. 18 W. Through about 15 ft of 

brown-weathering shale below dark-gray shale, northeast across 

gully from road. Same as 17056-PC and 17209-PC. Cravenoceras 

hesperium Zone. Collected by M. Gordon, Jr., and W. E. McCaslin, 

September 15, 1974.

25548-PC. Millard County, Burbank Hills Quad. On slope about 

300 ft north of Jensen Wash, in SW 1/4 NE 1/4 NE 1/4 sec. 35, 

T. 22 S., R. 18 W. Fossils weathering out 15-60 ft below 4-ft-thick 

limestone bed at top of ridge below downfaulted block (about 25-30 

ft of throw). Same as 17217-PC. Carlinia phillipsi beds, Rhipidomella nevadensis Zone. Collected by M. Gordon, Jr., and W. E. 

McCaslin, Sept. 15, 1974.

25550-PC. Millard County, Burbank Hills Quad. At a patch of 

light-brown shale just above thin limestone bed in first drainage 

800 ft west of Jensen Wash. About in middle of western side of 

NW V4 SW V4 SE V4 sec. 35, T. 22 S., R. 18 W. Drainage runs north 

and then curves into Jensen Wash. Same unit as 25547-PC but to 

south. Cravenoceras hesperium Zone. Collected by M. Gordon, Jr., 

and W. E. McCaslin, Sept. 15, 1974.

25551-PC. Millard County, Gandy NE Quad. On west limb of 

Bishop Springs anticline, on slope along east side of north-trending 

drainage, 1,700 ft north of south line and 2,450 ft east of west line 

of partial sec. 31, T. 15 1/2 S., R. 17 W., 2 1/4 mi southeast of 

northwest tip of Foote Range. Anthracospirifer bed and overlying 

30 ft of shale, at northwest strike and dip 73° E. on geologic map 

(Hose and Ziony, 1963). Collected by M. Gordon, Jr., and W. E. 

McCaslin, Sept. 17, 1974.

25553-PC. Millard County, Gandy NE Quad. West side of wash on 

east base of Foote Range, 1,800 ft north of south line and 2,150 ft

east of west line of partial sec. 31, T. 15 1/2 S., R. 17 W. Collected 

by M. Gordon, Jr., and W. E. McCaslin, Sept. 18, 1974.

25557-PC. Millard County, Gandy NE. Quad. Foote Range. Tan 

patch of shale 400 ft N. 70° W. from sec. cor. R. 18 W./R. 17 W. and 

sec. 30/31 in R. 17 W. (corner is ticked but not shown on geologic 

map (Hose and Ziony, 1963); marker is dated 1959). Paracravenoceras barnettense Zone, upper part. Collected by M. Gordon, Jr., 

and W. E. McCaslin, Sept. 18, 1974.

25558-PC. Juab County, Granite Mountain SW Quad. On line of 

Granite Mountain measured section. Fossils from concretions on 

north bank of drainage, about 15 ft above top of marker bed approximately 1,800 ft due south of northeast corner sec. 18 (unsurveyed), 

T. 14 S., R. 16 W. Goniatites americanus Zone. Collected by 

M. Gordon, Jr., and W. E. McCaslin, Sept. 19, 1974.

25562-PC. Juab County, Granite Mountain SW Quad. On north 

side of drainage in NE i/4 SW 1/4 SE 1/4 sec. 7, T. 14 S., R 16 W., 

on northeast side of Granite Mountain. Zone of brown shale containing orange-weathering concretions; fossils weathering from 

shale and on limestone plates. Goniatites granosus Zone. Collected 

by M. Gordon, Jr., Sept. 19, 1974.

25563-PC. Millard County, Cowboy Pass SW Quad. Skunk Spring 

section. In Willow Gap Member of Sadlick (1966) (Chainman Formation), 20-22 ft below top, 100-200 ft north of gravel barrier that 

diverts Willow Spring drainage; SW V4 SW V4 NE 1/4 sec. 28 

(unsurveyed), T. 17 S., R. 16 W., 1,550 ft northwest of Skunk 

Spring. Approximately the same bed as 15363-PC. Collected by 

M. Gordon, Jr., and W. E. McCaslin, Sept. 20, 1974.

25566-PC. Millard County, Conger Mountain Quad. Confusion 

Range, Wallet Gulch section; just below top of ridge, on east slope 

of ridge east of Wallet Gulch and in line with main part of Wallet 

Gulch; from lowest bed in a limestone cliff, about 6-8 ft high. 

SW 1/4 NW !/4 sec. 27 (unsurveyed). Same limestone unit as 17214- 

PC, but from basal bed of unit and several hundred feet northeast 

of that collection and in line with main part of Wallet Gulch. 

Collected by M. Gordon, Jr., and W. E. McCaslin, Sept. 20, 1974.

28610-PC. Millard County, Burbank Hills Quad. Jensen Wash section. Small soft shale hill on line of measured section, NW lk SE x/4 

SE V4 sec. 35, T. 22 S., R. 18 W. Same locality and stratigraphic 

interval as 17194-PC. Collected by M. Gordon, Jr., and T. W. 

Henry, Aug. 12, 1982.

28611-PC. Millard County, Burbank Hills Quad. Same locality as 

28610-PC, but from dip slope of hill and 30 ft upsection. Same 

locality and stratigraphic unit as 17187-PC. Paracravenoceras 

barnettense Zone. Collected by M. Gordon, Jr., and T. W. Henry, 

Aug. 12, 1982.

28612-PC. Millard County, Burbank Hills Quad. Jensen Wash section, upper part. Same locality and stratigraphic unit as 17059- 

PC, 17217-PC, and 25548-PC. Collected by M. Gordon, Jr., and 

T. W. Henry, Aug. 12, 1982.

28623-PC. Millard County, Gandy NE Quad. Small outcrop of soft 

brown shale just north of main wash, in southern part of sec. 24, 

630 ft north of south line and 2,400 ft west of east line of sec. 24; 

NW V4 SW V4 SE V4 sec. 24, T. 15 S., R. 18 W. Paracravenoceras 

barnettense Zone, upper part. Collected by M. Gordon, Jr., T. W. 

Henry, and Mark Rich, Aug. 14, 1982.

28628-PC. Juab County, Granite Mountain SW Quad. Granite 

Mountain measured section. Near center sec. 18, T. 14 S., R. 16 W. 

Same locality and unit as 17092-PC. Dark jointed fine-grained 

limestone and shale, containing Lunulazona sadlicki; includes 

Bactrites from fine-grained brownish-gray limestone 10 ft above 

gastropod bed. Collected by M. Gordon, Jr., and T. W. Henry, 

Aug. 15, 1982.

28637-PC. Juab County, Granite Mountain SW Quad. Granite 

Mountain measured section on east slope of cuesta formed by west-
104 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

dipping marker limestone bed (Skunk Spring Limestone Member 

of Sadlick, 1966). Float from 3-ft interval of silty shale immediately below basal chert of marker bed, 92-95 ft above base of 

Chainman Shale. Collected by M. Gordon, Jr., Aug. 16, 1982.

Metric-Conversion Table

U.S. customary units used in the preceding Register may be converted to metric units by using the following conversion table:

To convert U.S. customary unit: To metric unit: Multiply by:

Mile (mi)

Yard (yd)

Foot (ft)

Inch (in.)

Kilometer (km)

Meter (m)

Meter (m)

Centimeter (cm)

1.61

.914

.305

2.54

REFERENCES

Arnold, C. A., and Sadlick, Walter, 1962, A Mississippian flora from

northeastern Utah and its faunal and stratigraphic relations:

Michigan University, Museum of Paleontology Contribution 17,

no. 11, p. 241-263. 

Bacon, C. S., Jr., 1948, Geology of the Confusion Range, west-central

Utah: Geological Society of America Belletin, v. 59, no. 10,

p. 1027-1052. 

Batten, R. L., 1958, Permian Gastropoda of the southwestern United

States; Pt. 2: American Museum of Natural History Bulletin,

v. 114, art. 2, p. 157-246, 10 pis.

 1966, The lower Carboniferous gastropod fauna from the 

Hotwells Limestone of Compton Martin, Somerset [Parts I and 

II]: Palaeontographical Society Monographs, v. 119 (1965 pub. 

1966), p. 1-52; v. 120 (1966), p. 53-109.

 1967, Thoughts on the genus Ptychomphalina Fischer, 1887 

and the family Eotomariidae Wenz, 1938: Journal of Paleontology, v. 41, no. 1, p. 261-264. 

-1972, Permian gastropods and chitons from Perak, Malaysia;

Part 1, Chitons, bellerophontids, euomphalids, and pleurotomarians: American Museum of Natural History Bulletin, v. 147, 

no. 1, p. 5-44.

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INDEX

107

Abstract ......................................... 1

Acknowledgments ................................ 2

Aclisina ........................................ 80

sp ........................................... 5

Adetognathus unicornis Condont Zone ............. 5

Agassizocrinus-bearing shale ................. 12,13

(Aglaoglypta), Bellerophon ....................... 33

albapinensis, Retispira ......................... 5,39

Amaurotoma. ..................................... 4

Ammonoid zones, gastropod assemblages .......... 21

(Amphiscapka.), Straparollus .................. 82,83

Amsden Formation ............................... 5

(Ananias), Glabrocingulum ............... 8,58,66,77

nevaden.ie, Glabrocingulum .......... 2,4;pls.7,67

seminudum, Glabrocingulum .... 5,19,20,21,22,26,

32,63,64,65,66;pl.6 

Anematina ......................... 4,8,25,87,97;pl.8

micula ...................................... 87

proutana ................................. 87,97

rockymontana ............................... 87

sp. ............................... 15,23,87;pl.8

angularis, Straparollus (Euomphalus) ............ 82

angulata, Mourlonia ........................ 51,54,55

Ptychamphai'.ina .............................. 54,55

angulosa, Bcylea ................................ 49

(Angyomphalus), Trepospira .................. 3,8,46

discus, Trepospira ........................... 47

excavata, Trepospira ......................... 47

excavatus, Trepospira ...................... 6,46

kentuckiensis, Trepospira ................. 46,52

penelenticulata, Trepospira ................... 46

regularis, Trepospira ............. 8,22,23,46; pl.3

anneae, Sinv.itina ............................. 2,28

Sinuitina (Vorticina) ..................... 28,29

Anomphalus ..................................... 4

Apachella ....................................... 67

Arizona .......................................... 4

aspeniana, Gosseletina ............................ 3

B

baconi, Trepospira (Trepospira) ...... 20,22,24,47;pl.3

bambooform.ls, Meekospira ....................... 97

barbarae, Hematites ..................... 14,21,47,61

barnettense, Paracravenoceras ................. 11,47

barquensis, Bellerophon .......................... 39

Retispira ................................... 39

batteni, Meekospira .............................. 97

Baylea ...................................... 38,49

angulosa .................................... 49

coheni ...................................... 49

minuta ..................................... 49

okawensis ................................... 49

sinuata ..................................... 49

trifibra ..................................... 49

yvanii ...................................... 49

sp ................................ 17,25,49;pl.7

[Trepospira] inflata .......................... 58

stellaeformis ............................ 58

beedia, Bucanopsis .............................. 40

Retispira ................................... 39

bella, Bellazona ............ 4,8,10,23,66,80,81,98;pl.9

[Italic page numbers indicate major references]

Loxonema ................................. 2,80

Bellazona ............................... 2,8,80;pl.9

bella .................. 4,8,10,23,66,80,81,98;pl.9

polita ................. 1,11,14,15,17,23,82,98;pl.9

Bellerophon ............................. 3,31,33;pl.l

barquensis .................................. 39

bilabiatus ................................... 34

blairi .................................... 30,35

cyrtolites .................................. 28,29

helena ...................................... 34

hiulcus ..................................... 35

hiuleus ..................................... 34

jeffersonensis ................................ 34

lineolatus ................................... 39

mansfieldianus .............................. 33

michiganensis ............................... 39

missouriensis ............................... 40

monroensis ................................. 40

nautiloides .................................. 30

panneus .................................... 34

reticulatus ................................ 2,40

rugosiusculus .......................... 28,29,34

taeniatus ............................... 29

scotti ....................................... 34

terti/is ...................................... 44

u/ricfci ...................................... 34

vasulites .................................... 33

vinculatus .................................. 34

whittleseyi .................................. 35

sp. indet ..................................... 5

fAg/oogfyptaJ ............................... 33

(Bellerophon) ................ 3,5,8,22,33,37;pl.l

chesterensis ..................... 34,35,36,37

claxtonensis .......................... 34,35

gibsoni .............................. 34,35

majusculus ...................... 4,34,35,37

mansfieldianus .......................... 34

menardensis ....................... 34,35,36

needlensis ................ 16,21,22,25,26,34,

36,37; pi. 1 

panneus ................................ 34

pitkinensis ........................... 34,35

scissilis .............................. 34,35

spergenensis ....................... 34,35,36

sublaevis ............................ 34,35

vespertinus ............ 1,5,11,14,16,18,19,20,

22,25,26,34,36,37 ;pl.l 

welshi ............. 13,21,22,25,34,36,48;pl.l

sp. ...................................... 6

sp.A ........................ 14,22,26,37;pl.l

sp.indet ...................... 13,16,17,25,36

(Pharkidonotus) .......................... 33,34

(Bellerophon),Bellerophon ........ 3,5,8,22,33,37;pl.l

chesterensis, Bellerophon ............. 34,35,36,37

claxtonensis, Bellerophon .................. 34,35

gibsoni, Bellerophon ...................... 34,35

majusculus, Bellerophon .............. 4,34,35,37

mansfieldianus, Bellerophon ................. 34

menardensis, Bellerophon ............... 34,35,36

needlensis, Bellerophon .......... 16,21,22,25,26,

34,36,37;pl.l 

panneus, Bellerophon ........................ 34

pitkinensis, Bellerophon ................... 34,35

scissilis, Bellerophon ...................... 34,35

Page

spergenensis, Bellerophon ............... 34,35,36

sublaevis, Bellerophon .................... 34,35

vespertinus, Bellerophon ...... 1,5,11,14,16,18,19,

20,22,25,26,34,36,

37;pl.l

welshi, Bellerophon ..... 13,21,22,25,34,36,48;pl.l

sp., Bellerophon .............................. 6

sp.A, Bellerophon ............... 14,22,26,37; pl.l

sp.indet., Bellerophon ............. 13,16,17,25,36

Bellerophontacea ............................. 21,27

Bellerophontidae ................................ 33

Bellerophontinae ................................ 33

bellula, Hammatospira ............................ 5

Bembexia .................................. 53,57,68

ellenae ...................................... 58

lativittata ................................... 68

magna ................................... 51,54

nodimarginata .............................. 70

nodomarginata ........................... 68,69

Big Snowy Group ................................ 6

bilabiatus, Bellerophon .......................... 34

binodosum, Glabrocingulum ................... 5,62

Glabrocingulum

(Glabrocingulum) ..... 14,17,21,22,25,26,

58,60,63,64,

67;pls.5,6

biserialis, Turbonitella ............................ 5

Bishop Springs anticline ......................... 14

blairi, Bellerophon ............................ 30,35

blayeyanus, Euphemites ....................... 29,32

boonensis, Euomphalus .......................... 82

Straparollus (Euomphalus) ................... 82

Borestus ...................................... 4,77

brazeriana, Dictyotomaria ...................... 3,78

brazerianum, Phymatopleura ..................... 78

brazerianus, Productus ........................... 4

Wellergyi .................................... 3

brooksensis, Straparollus (Euomphalus) ........ 82,83

Brown's Wash-Wallet Gulch, partial section ...... 17

Bucanellinae .................................... 27

Bucanopsis beedia ............................... 40

deflectus .................................... 39

minima ..................................... 40

ornatus ..................................... 40

perelegans .................................. 39

wauerliensis ................................. 39

(Retispira) reticulata ..................... 2,39,40

bulimiformis, Bulimorpha ........................ 94

Bulimorpha ............................... 8,94;pl.9

bulimiformis ................................ 94

elegans ................................... 3,94

elongata .................................... 94

minor ...................................... 94

whitfieldi ................................... 94

sp ................................ 17,25,94;pl.9

Burbank Hills .................................. 21

burbankensis,Ptychomphalina ... 20,23,24,54,71;pl.3 

buttsi, Naticopsis (Naticopsis) ................. 87,88

Camp Canyon ................................... 17

canaliculata, Girtyspira .......................... 98

cancellata, Mourlonia ............................ 51
108 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Page

Caninia ........................................ 83

carbonaria, Pleurotomaria ....................... 86

carbonifera, Leiorhynchoidea .................. 12,15

carinata, Mourlonia ............................. 52

carinatus, Helix ................................. 51

carlbransoni, Dictyotomaria .................... 6,78

carleyana, Naticopsis (Naticopsis) .............. 87,88

Carlinia phillipsi ................................ 85

castlemanensis, Worthenia ....................... 75

Catazona ............................... l,8,77;pl.7

rudilirata ............... 5,ll,16,17,23,25,78;pl.7

Catazona rudilirata assemblage ........... 1,25,26,27

Cerithioides ..................................... 80

Chainman Shale, gastropod distribution .......... 1,5

gastropod occurrence data ..................... 7

chesterense, Glabrocingulum (Glabrocingulum) .... 58

chesterensis, Bellerophon (Bellerophon) .... 34,35,36,37

Strophostylus ............................... 86

Trepospira (Trepospira) ................... 47,58

Wellergyi ................................... 56

Chesterian gastropods ............................ 5

choctawensis, Goniatites ......................... 15

Cinclidonema ............................. 8,86;pl.7

texanum .................................... 86

sp ................................ ll,24,86;pl.7

cincta, Retispira ................... 11,14,19,22,23,39,

41,43,44;pl.2 

circulare, Platyceras (Platyceras) .................. 85

circumsecta, Girtyspira ................ 16,25,98; pl.9

Clathrospira ................................. 53,57

claviger, Pseudozygopleura

(Stephanozyga) ............. 16,17,25,93; pl.9

claxtonensis, Bellerophon (Bellerophon) ........ 34,35

clinovata, Naticopsis (Naticopsis) ..... 11,15,16,17,23,

25,27,87,89; pl.8 

Cluthoceras glicki ............................... 77

coheni, Baylea ................................... 49

colpites, n. gen. aff ............................... 6

Composition of the fauna ......................... 7

compressus, Euphemites ...................... 30,31

Compsonema fragile .............................. 5

confusionense, Glabrocingulum .................... 1

Glabrocingulum

(Glabrocingulum) ... 5,12,14,15,20,22,24, 

58,59,60,61,62,64;pls.5,6

Naticopsis (Naticopsis) ... 11,14,15,16,17,18,23,25,

87,88; pl.8 

Conger Mountain ............................... 19

Conger Spring .................................. 18

cordiformis, Sinuitina ........................... 28

costata, Lunulazona ............. 5,11,14,17,22,23,68,

70,71,72;pl.4 

Coyote Pass ..................................... 19

cracens, Euphemites .............. 19,22,26,30,31;pl.2

Cravenoceras hesperium ............... 5,13,19,20,21

Cravenoceras hesperium Zone ....... 1,11,12,14,20,21,

22,23,24,25,26,85 

Cravenoceras kingi .............................. 14

Cravenoceras kingi bed .......................... 24

crispa, Sinuitina (Sinuitina) ...... 15,22,23,27,29;pl.l

(cyclonema) strigillata, Pleurotomaria ............. 75

(Cylicioscapha), Straparollus ..................... 82

cyrtolites, Bellerophon ........................ 28,29

Sinuitina (Vorticina) ........................ 28

D

deflectus, Bucanopsis ............................ 39

delphicola, Loxonema ............................ 90

i, Trepospira ............................. 48

sus, Naticopsis ............................ 87

Ptychomphalus .............................. 52

desereti, Euconospira ......... 18, 20,21,22,73,75;pl.4

Deseretospira ....................... 2,8,55,56,57;pl.7

monilifera .................... 2,20,23,24,56; pl.7

Deseretospirides ............................... 2,55

diadema, Trepospira (Trepospira) .... 5,13,14,18,20,21,

22,25,26,48; pl.3 

Diamond Peak Formation ........................ 4,5

Diaphragmus .................................... 4

Page

Dictyotomaria ...................... 6,8,56,57,78;pl.7

brazeriana ................................ 3,78

carlbransoni .............................. 6,78

meekana .................................... 78

wortheni .................................... 78

yochelsoni .................................. 78

sp ................................ 17,25,79;pl.7

difficile, Loxonema .............................. 90

dinglense, Rhineoderma ....................... 3,56

discoidalis, Trepospira (Trepospira) ............ 48,57

discus, Trepospira (Angyomphalus) ............... 47

disjuncta, Euconospira ...................... 73,74,75

Distribution of gastropods in study area .......... 1,8

Donaldina ...................................... 4,6

sp ........................................... 5

dubia, Naticopsis (Naticopsis) .................... 87

E

Eirlysia ....................................... 2,57

Elasmonematidae ............................... 87

elegans, Bulimorpha ........................... 3,94

eliasi, Retispira .......................... 2,39,40,42

ellenae, Bembexia ............................... 58

Glabrocingulum (Glabrocingulum) ......... 58,59

elongata, Bulimorpha ............................ 94

Ely Limestone .................................. 1,5

encloides, Platyceras ............................. 85

Eocryptaulina ................................... 54

Eotomaria ................................... 53,57

Eotomariidae ................................ 49, 50

Eotomariides ................................. 50,57

Eotomariinae ................................... 50

Euconospira .......................... 3,8,22,73;pl.4

desereti ................... 18,20,21,22,73,75;pl.4

disjuncta .............................. 73,74,75

gradilis ........................ 19,22,73,74;pl.4

missouriensis ............................... 73

sturgeoni ................................ 73,74

turbiniformis ................................. 73

waterlooensis ............................. 73,74

Eumorphoceras Zone ............................ 83

Eumorphoceras bisulcatum Zone .................. 26

Euomphalacea ............................... 81,82

Euomphalidae ................................... 82

Euomphalus boonensis ........................... 82

luxus ....................................... 82

perspectivus ................................. 82

spergenensis ................................. 3

(Euomphalus), Straporollus ............ 6,8,23,82;pl.8

angular is, Straparollus ...................... 82

boonensis, Straparollus ...................... 82

brooksensis, Straparollus .................. 82,83

exortivus, Straparollus ....................... 82

illinoisensis, Straparollus ................. 82,84

intermedius, Straparollus ... 1,5,6,11,13,14,15,16,

17,18,19,20,23,25,

82,83,84;pl.3

latus, Straparollus ........................... 82

multistriatus, Straparollus ................... 82

nodibasis, Straparollus ............ 5,11,16,17,23,

25,82,84;pl.3 

nodosus, Straparollus ........................ 83

obtusus, Straparollus ........................ 82

pancakensis, Straparollus ................ 5,82,84

pernodosus, Straparollus ..................... 83

planodorsatus, Straparollus ............... 82,83

roberti, Straparollus ......................... 82

similis, Straparollus ......................... 82

subplanus, Straparollus ...................... 82

subrugosus, Straparollus ...................... 4

subsulcatus, Straparollus .................... 84

tricarinatus, Straparollus .................. 3,82

utahensis, Straparollus ...................... 82

xylacus, Straparollus .................... 6,82,84

sp., Straparollus ................... 21,23,84;pl.8

Euphemites ...................... 3,5,8,22,29;pls.l,2

blayeyanus ............................... 29,32

compressus .............................. 30,31

cracens ...................... 19,22,26,30,31;pl.2

Page

galericulatus ........................... 30,31,32

incarinatus .............................. 30,31

lentiformis .................................. 30

multiliratus ................................. 32

nevadensis .............. 5,17,20,22,25,30,32;pl.2

randolphenisis ........................... 30,31

sacajawensis ................ 6,11,20,22,25,26,30,

32,33;pl.2 

sedaliensis ............................... 30,32

subglobosus .............................. 30,32

vittatus .................................. 29,32

sp ........................................... 6

sp.A ................... 14,19,24,26,29,31,32; pl.2

sp.B .................................. 8,33;pl.l

sp.indet............................. 11,22,23,31

Euphemitinae ................................... 29

evansvillensis, Meekospira ........................ 97

evolutus, Platyceras .............................. 85

excavata, Trepospira (Angyomphalus) ......... 6,46,47

exortivus, Straparollus (Euamphalus) ............. 82

Faberophyllum ................................... 4

Faberophyllum Zone .............................. 3

Foote Ranch locality ............................. 12

Foote Range .................................... 12

Foraminiferal zones, gastropod assemblages ....... 21

foutainensis, Ptychomphalus ..................... 52

fragile, Compsonema ............................. 5

G

galericulatus, Euphemites ................... 30,31,32

gandyensis, lanthinopsis ........... 14,20,21,23,25,94,

95,96;pl.9 

Gastropod assemblages, ammonoid and

foraminiferal zones .................. 21

Gastropod, gen. and sp. indet................. 99;pl.9

Gastropods, distribution in study area ............ 1,8

diversity and facies control................... 26

as guide fossils .............................. 26

genevievensis, Naticopsis

(Naticopsis) ............. 16,17,23,25,87,

88,89;pls.8,9 

gibsoni, Bellerophon (Bellerophon) ............. 34,35

Girtyspira ............................. 4,6,8,98; pl.9

canaliculata ................................. 98

circumsecta ....................... 16,25,98;pl.9

pygmaea .................................... 98

glaber, Soleniscus ............................ 96,97

Glabrocingulides .............................. 2,57

Glabrocingulum .............. l,2,7,22,57,58;pls.5,6,7

binodosum ................................ 5,62

Glabrocingulum binodosum assemblage ........... 25

Glabrocingulum confusionense assemblage ...... 1,24

Glabrocingulum hosei ........................... 42

Glabrocingulum hosei assemblage .............. 1,24

Glabrocingulum inflatum ......................... 5

quadrigatum ............................ 5,20,32

Glabrocingulum quadrigatum

assemblage .................. 1,24,26,27

Glabrocingulum sp. indet ........................ 21

(Ananias) ............................ 8,58,66,77

nevadense ........................... 2,4;pl.7

nevadensis ........................... 66,67

seminudum ............. 5,19,20,21,22,26,32,

63,64,65,66;pl.6 

(Glabrocingulum) .................. 3,8,46,58,66

binodosum .......... 14,17,21,22,25,26,58,60,

63,64,67;pls.5,6 

chesterense .............................. 58

confusionense ........ 5,12,14,15,20,22,24,58,

59,60,6/,62,64;pls.5,6 

ellenae ............................... 58,59

granulosum ................. 11,14,22,23,58,

59,64,66;pl.6 

grayvillense ............................. 58

hosei ..................... 12,14,20,22,24,47,

57,58,61,64,65;pls.5,6
INDEX 109

Page

inflatum ........................... 58,59,60

mephitifontis .............. 11,15,22,23,58,59,

64,67;pls.6,7 

minutum ............................... 58

quadrigatum ............ 5,11,12,13,14,15,20,

21,22,25,58,59,

61,62;pls.5,6

sinuatum ............................... 58

Stella ................................... 58

stellaeforme .......................... 58,63

sp.A ......................... 8,22,23,63; pl.7

sp.B ....................... 19,22,26,64; pl.7

sp.C ............................. 13,64;pl.6

sp.indet .................................. 6

(Glabrocingulum), Glabrocingulum ....... 38,46,58,66

binodosum, Glabrocingulum ..... 14,17,21,22,25,

26,58,60,63,64,

67;pls.5,6

chesterense, Glabrocingulum ................. 58

confusionense, Glabrocingulum .. 5,12,14,15,20,22,

24,58,59,60,61,

62,64;pls.5,6

ellenae, Glabrocingulum .................. 58,59

granulosum, Glabrocingulum .... 11,14,22,23,58,

59,64,66;pl.6 

grayvillense, Glabrocingulum ................. 58

hosei, Glabrocingulum ......... 12,14,20,22,24,47,

57,58> 61,64,65;pls.5,6 

inflatum, Glabrocingulum ............... 58,59,60

mephitifontis, Glabrocingulum . 11,15,22,23,58,59,

64,67 ;pls.6,7 

minutum, Glabrocingulum ................... 58

quadrigatum, Glabrocingulum .. 5,11,12,13,14,15,

20,21,22,25,58,

59,61,62;

pls.5,6

sinuatum, Glabrocingulum ................... 58

Stella, Glabrocingulum ....................... 58

stellaeforme, Glabrocingulum .............. 58,63

sp.A, Glabrocingulum ............ 8,22,23,63;pl.7

sp.B, Glabrocingulum ........... 19,22,26,64;pl.7

sp.C, Glabrocingulum ................. 13,64; pl.6

sp.indet., Glabrocingulum ..................... 6

glenparkensis, Platyceras ......................... 85

glicki, Cluthoceras ............................... 77

glomerosa, Naticopsis (Naticopsis) ............ 5,87,88

Glyptotomciria ................................... 78

Goniatites americanus Zone ............. 1,8,10,22,23

Goniatites choctawensis .......................... 15

Goniatites granosus .............................. 15

Goniatites granosus Zone ............ 10,14,15,17,19,

22,23,28 

Goniatites, Jensen Wash section .................. 19

Goniatites multiliratus Zone ................. 10,22,23

Gosseletinci ...................................... 6

aspeniana .................................... 3

gracile, Platyceras (Orthonychia) striatulum ........ 3

gradilis, Euconospira ............... 19,22,73,74; pl.4

Granite Mountain section ........................ 1,8

granosus, Goniatites .............................. 15

granulosum, Glabrocingulum

(Glabrocingulum) ..... 11,14,22,23,58,59,

64,66;pl.6

grayvilleme, Glabrocingulum (Glabrocingulum) ... 58 

Gyronematinae ................................. 86

H

haliotoides, Platyceras (Platyceras) ................ 85

Hammatospira bellula ............................ 5

hartti, Naticopsis (Naticopsis) ................. 87,88

Heath Formation ................................. 6

Helena, Bellerophon .............................. 34

Helix carinatus .................................. 51

Hematites ....................................... 20

barbarae ............................ 14,21,47,61

hesperium, Cravenoceras ............... 5,13,19,20,21

High-spired gastropods ........................... 8

hiulcus, Bellerophon ............................. 35

hiuleus, Bellerophon ............................. 34

Page

Holopea sp ....................................... 3

Holopeidae ...................................... 86

Holotype, definition .............................. 7

Horseshoe Shale Member ......................... 5

hosei, Glabrocingulum ......................... 1,42

Glabrocingulum

(Glabrocingulum) .... 12,14,20,22,24,47,

57,58,61,64,65;pls.5,6

howi, Naticopsis ................................. 88

Naticopsis (Naticopsis) ....................... 87

(Hypergonia), Stegocoelia ........................ 80

Hypotype, definition .............................. 7

I

lanthinopsis ...................... 4,68,88,94; pls.8,9

gandyensis ...................... 14,20,21,23,25,

44,95,96;pl.9 

keyesi ................................... 94,97

littonanus ................................... 94

melanoides .................................. 94

pinguis ..................................... 94

reticulatus .................................. 94

stinesvillensis ............................... 94

subcorpulentus ........................... 94,97

tantillus .................................... 94

sp ................................. 8,23,96;pl.9

sp.A .............................. 13,95,97;pl.9

sp.B .............................. 14,20,95;pl.8

lanthinopsis, Palaeostylus (Pseudozygopleura) ...... 6

Idaho ............................................ 3

illinoiensis, Stegocoelia (Stegocoelia) .............. 80

Trepospira (Trepospira) ................... 47,48

illinoisensis, Straparollus (Euomphalus) ....... 82,84

incarinatus, Euphemites ...................... 30,31

Indian Pass area ................................ 15

inflata, Baylea [Trepospira] ...................... 58

Inflatia ......................................... 13

inflatum, Glabrocingulum ......................... 5

Glabrocingulum (Glabrocingulum) ....... 58,59,60

inornate, Naticopsis (Naticopsis) ................ 4,87

inornatum, Platyostoma .......................... 87

insculpta, Nettsonia ............................. 67

intermedius, Straparollus

(Euomphalus) ...... 1,5,6,11,13,14,15,16,

17,18,19,20,23,25,

82,83,84;pl.3

Introduction ..................................... 2

iowensis, Mourlonia ............................. 51

Pleurotomaria ............................... 51

(Jedria), Naticopsis ........................... 6,8,90

sp., Naticopsis .................. 17,23,25,90;pl.8

jeffersonensis, Bellerophon ....................... 34

Jensen Wash section ............................ 19

jensenensis, Retispira .... 15,20,22,25,39,41,43,44;pl.2

K

kentuckiensis, Mourlonia ......................... 51

Stegocoelia (Stegocoelia) ..................... 80

Trepospira (Angyamphalus) ............... 46,52

keyesi, lanthinopsis ........................... 94,97

keytei, Sinuitina ................................. 28

Sinuitina (Vorticina) ........................ 29

kingi, Cravenoceras .............................. 14

knighti, Loxonema ................................ 90

Knightites (Retispira) textilis ..................... 44

(Retispira) sp.A ............................. 32

Knightitinae .................................... 37

lativittata, Bembexia ............................. 68

Lunulazona ............................ 68,71,72

latum, Platyceras (Platyceras) .................... 85

lotus, Straparollus (Euomphalus) ................. 82

lauta, Pseudozygopleura ......................... 23

Page

Pseudozygopleura (Pseudozygopleura) ... 18,20,25,

92,93;pl.9 

Leiorhynchoidea carbonifera ................... 12,15

Leiorhynchoidea-Richardsonites bed ........... 12,13

lentiformis, Euphemites .......................... 30

lineolata, Retispira .............................. 33

lineolatus, Bellerophon ............................ 39

Liospirinae ..................................... 46

/irate, Pleurotomaria ............................ 69

littonanus, lanthinopsis .......................... 94

Localities register ............................... 99

longi, Worthenia ................................ 75

Lophospiridae ................................... 75

Loxonema ............................ 8,15,25,80;pl.9

bella ..................................... 2,80

delphicola .................................. 90

difficile ..................................... 90

knighti ..................................... 90

pikense ..................................... 90

tenuilineatum ............................... 90

wortheni .................................... 91

yandellanum ................................ 90

sp. ................................ 8,23,91;pl.9

Loxonematacea ................................. 90

Loxonematidae .................................. 90

Lunulazona ......................... 1,7,8,67,68;pl.4

costata ...........5,11,14,17,22,23,68,70,71,72;pl.4

Lunulazona costata assemblage ................... 23

lativittata .............................. 68,71,72

Lunulazona nodomarginata assemblage ......... 1,22

nodomarginata .................. 4,8,10,22,23,66

68,69,71,72;pl.4 

soofei ............... 13,15,22,26,68,71,72,73;pl.4

sadlicki .............. 5,ll,20,22,24,55,68,70;pl.4

Lunulazona sadlicki assemblage ................ 1,24

springeri .................................... 68

utahensis ................. 12,1522,68,71,91;plA

sp.A ......................................... 5

luxus, Euomphalus .............................. 82

M

Macluritacea .................................... 81

(Macrocheilus) regularis, Soleniscus .............. 96

Macrochilina worthenanus ....................... 97

madisonensis, Naticopsis (Naticopsis) .......... 87,89

magna, Bembexia ............................ 51,54

Ptychomphalina .......................... 54,55

majusculus, Bellerophon (Bellerophon) ..... 4,34,35,37

mansfieldianus, Bellerophon ..................... 33

Bellerophon (Bellerophon) .................... 34

marcouiana, Worthenia .......................... 75

mariona, Naticopsis (Naticopsis) .................. 87

meekana, Dictyotomaria .......................... 78

Meekospira ........................... 4,8,80,97; pl.9

Meekospira bambooformis ........................ 97

batteni ...................................... 97

evansvillensis ............................... 97

minute ..................................... 97

mississippiensis ............................. 97

sp .................... 5,12,13,16,17,25,97,98;pl.9

sp.indet ...................................... 6

Meekospiridae .................................. 97

melanoides, lanthinopsis ......................... 94

menardensis, Bellerophon (Bellerophon) ...... 34,35,36

mephitifontis, Glabrocingulum

(Glabrocingulum) ..... 11,15,22,23,58,59,

64,67;pls.6,7 

Meramecian gastropods ........................... 3

me.rria.mi, Richardsonites ........... 1,12,19,21,26,84

Mesoblastus ...................................... 4

Metoptoma peroccidens ............................ 4

michiganensis, Bellerophon ...................... 39

Retispira ................................ 39,42

Microdoma sp. ................................... 5

Microdomatacea ................................. 87

micula, Anematina .............................. 87

Bucanopsis ................................. 40

Retispira .............................. 39,41,44

Trepospira (Trepospira) ................... 47,48
110 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

minor, Bulimorpha .............................. 94

minuta, Baylea .................................. 49

Meekospira ................................. 97

minutum, Glabrocingidum (Glabrocingulum) ...... 58

mississippiensis, Meekospira ..................... 97

Pleurotomaria ............................ 51,76

Worthenia .................................. 76

Worthenia (Yochelsonospira) ................. 77

missouriensis, Bellerophon ....................... 40

Euconospira ................................ 73

Retispira ................................... 39

Moffat Trail Limestone Member ................... 5

Mollusks, Jensen Wash section ................... 20

monilifera,Deseretospira ........... 2,20,23,24,56;pl.7

Monroe Canyon Limestone, gastropod fauna ........ 4

monroensis, Bellerophon ......................... 40

Retispira ................................ 39,41

Montana ......................................... 6

Mourlonia ........................ .8,50,53,57,68;pl.4

angulata ............................... 51,54,55

cancellata .................................... 51

carinata .................................... 52

iowensis .................................... 51

kentuckiensis ................................ 51

nortfwiewensis ........................... 51,76

reloba ................................... 51,54

sablei ....................................... 68

solida ...................................... 51

stellaeformis ............................. 46,58

textiligera ................................ 51,52

textus ....................................... 51

venusta ....................... 8,23,51,52,54;pl.4

(Pseudobaylea) .............................. 51

(Woolnoughia) .............................. 51

sp ........................................... 5

Mourloniides .................................... .50

multiliratus, Euphemites ......................... 32

multistriatus, Straparollus (Euomphalus) ......... 82

Murchisonia .................................. 4,49

uninodocarinata .............................. 67

Murchisoniacea .................................. 79

Murchisoniidae ................................. 79

N

nasutum, Platyceras (Platyceras) .................. 85

Naticopsinae .................................... 87

Naticopsis .............................. l,23,87;pl.8

depressus ................................... 87

howi ....................................... 88

paucivolutus ................................ 87

remex ...................................... 88

suturicompta ................................ 88

(Jedria) ................................. 6,8,90

sp ...................... 17,23,25,90, pl.8

(Naticopsis) ........................ 4,5,6,8,86,87

buttsi ................................ 87,88

carleyana ............................ 87,88

clinovata ...... ll,15,16,17,23,25,27,87,89;pl.8

confusionensis ............. 11,14,15,16,17,18,

23,25,87,85; pl.8 

dubia ................................... 87

genevievensis ..... 16,17,23,25,87,88,89;pls.8,9

glomerosa ........................... 5,87,88

hartti ................................ 87,88

howi ................................... 87

inornate, .............................. 4,87

madisonensis .................... 87,89

mariona ............................ 87

picta ............................... 87

splendens ........................ 87,88

suturicompta ..................... 87,88

variata ............................. 87

waterlooensis ..................... 87,88

ziczac ............................... 87

sp ................................... 6

(Naticopsis), Naticopsis ................. 4,5,6,8,86,87

fiurtsi, Naticopsis ......................... 87,88

carleyana, Naticopsis ..................... 87,88

clinovata, Naticopsis ........... 11,15,16,17,23,25,

Page

27,87,89;pl.8 

confusionensis, Naticopsis ....... 11,14,15,16,17,18

23,25,87,88;pl.8 

dubia, Naticopsis ............................ 87

genevievensis, Naticopsis ........ 16,17,23,25,87,88

89;pls.8,9 

glomerosa, Naticopsis .................... 5,87,88

hartti, Naticopsis, ........................ 87,88

howi, Naticopsis ............................. 87

inornata, Naticopsis ....................... 4,87

madisonensis, Naticopsis ................... 87,89

mariona, Naticopsis ......................... 87

picta, Naticopsis ............................. 87

splendens, Naticopsis ..................... 87,88

suturicompta, Naticopsis .................. 87,88

variata, Naticopsis ........................... 87

waterlooensis, Naticopsis .................. 87,88

ziczac, Naticopsis ............................ 87

sp., Naticopsis ................................ 6

nautiloides, Bellerophon ......................... 30

nauvooensis, Pleurotomaris ...................... 76

Worthenia .................................. 76

Worthenia (Yochelsonospira) ................. 77

Needle Range ................................... 21

needlensis, Bellerophon

(Bellerophon) ................... 16,21,22,25,26,

34,36,37,-pl.l 

Neilsonia ............................... 8,56,67;pl.7

insulpta .................................... 67

nodomarginata .............................. 69

springeri .................................... 68

welleri .................................. 5,67,68

sp ............................. ll,23,25,67;pl.7

sp. indet .................................... 13

Neilsoniinae ................................. 50,67

Neritacea ....................................... .87

Neritopsidae .................................... 87

Nevada ........................................ 4,5

nevadense, Glabrocingulum (Ananias) .. 2,4,66,67;pl.7 

nevadensis, Euphemites ................ 5,17,20,22,25,

30,32;pl.2 

Pleurotomaria ............................ 66,77

Rhipidomella ....................... 19,21,26,66

Strophostylus ..................... 5,11,16,17,18

25,27,86; pl.8 

New species list .................................. 2

nodibasis, Straparollus (Euomphalus) ... 5,11,16,17,23,

25,82,84;pl.3 

nodimarginata, Bembexia ........................ 70

Pleurotomaria ............................ 22,67

nodomarginata, Bembexia ..................... 68,69

Lunulazona ...... 4,8,10,22,23,66,68,69,71,72;pl.4

Neilsonia ................................... 69

Pleurotomaria ............................ 68,69

Nodospira ............................... 53,67

nodosus, Straparollus (Euomphalus) .............. 83

nolani, Retispira ................ 5,11,14,20,21,22,25,

39,43,44;pl.2 

northviewensis, Mourlonia .................... 51,76

Worthenia .................................. 76

Worthenia (Yochelsonospira) ................. 77

nudidorsa, Sinuitina (Sinuitina) .................. 27

O

obtusus, Straparollus (Euomphalus) .............. 82

occidens, Platyceras (Orthonychia) ................. 4

Occurrence data .................................. 7

okawensis, Baylea ............................... 49

Stegocoelia (Stegocoelia) ..................... 80

Omospirinae .................................... 49

Opisthobranchia ................................ 98

ordinata, Retispira ................... 20,21,22,24,39

4I,43,44;pl.2 

ornata, Retispira ............................. 39,42

ornatus, Bucanopsis ............................. 40

(Orthonychia), Platyceras ........................ 85

occidens, Platyceras ........................... 4

striatulum, Platyceras ........................ 3

gracile, Platyceras ........................ 3

Page

sp., Platyceras ................................ 5

oxynotum, Platyceras (Platyceras) ................. 85

i, Worthenia (Yochelsonospira) ............. 77

Yochelsonospira ............................. 76

Pagodina ....................................... 67

Palaeostylus (Pseudozygopleura) ................... 4

(Pseudozygopleura) ianthinopsis ............... 6

Palaeozygopleura ............................. 90,91

venusta ..................................... 91

welleri ...................................... 91

pancakensis, Straparollus (Euomphalus) ...... 5,82,84

panneus, Bellerophon ............................ 34

Bellerophon (Bellerophon) .................... 34

Paracravenoceras ................................ 20

barnettense .............................. 11,47

Paracravenoceras barnettense Zone ...... 1,12,14,19,21

22,23,24,26 

Paratype, definition .............................. 7

Pareuryalox ..................................... 67

paucivolutus, Naticopsis ......................... 87

pealeanum, Rhineoderma ...................... 3,45

penelenticulata, Trepospira (Angyomphalus) ....... 46

perelegans, Bucanopsis ........................... 39

Retispira ................................... 39

pernodosus, Straparollus (Euomphalus) ........... 83

peroccidens, Metoptoma ........................... 4

perspectivus, Euomphalus ........................ 82

Peruvispira ..................................... 67

(Pharkidonotus), Bellerophon .................. 33,34

phillipsi, Carlinia ............................... 85

(Philoxene), Straparollus ......................... 82

Phymatifer ...................................... 83

(Phymatifer), Straparollus ....................... 82

Phymatopleura ............................... 56,57

brazerianum ................................ 78

springerensis ................................ 78

Phymatopleuridea ............................... 77

piasaense, Rhineoderma .......................... 56

picta, Naticopsis (Naticopsis) ..................... 87

pikense, Loxonetna ............................... 90

pinguis, Ianthinopsis ............................ 94

piso, Platyceras (Platyceras) ....................... 4

pitkinensis, Bellerophon (Bellerophon) .......... 34,35

planidorsatus, Straparollus (Euomphalus) ......... 83

planodorsatus, Straparollus (Euomphalus) ........ 82

Planospirina remex .............................. 88

planus, Straparollus ............................. 82

Platyceras ................................ 3,85;pl.8

encloides .................................... 85

evolutus .................................... 85

glenparkensis ............................... 85

pulcherrimum ............................... 85

subrotundum ............................... 85

(Orthonychia) ............................... 85

occidens ................................. 4

striatulum ............................... 3

gracile ............................... 3

sp. ...................................... 5

(Platyceras) .............................. 4,8,85

circulare ................................ 85

haliotoides .............................. 85

latum .................................. 85

nasutum ................................ 85

oxynotum ............................... 85

piso ..................................... 4

reversum ............................... 85

subelegans .............................. 85

subtrotundum .................. 12,20,85; pl.8

(Platyceras), Platyceras ....................... 4,8,85

circulare, Platyceras ......................... 85

haliotoides, Platyceras ....................... 85

latum, Platyceras ............................ 85

nasutum, Platyceras ......................... 85

oxynotum, Platyceras ........................ 85

piso, Platyceras ............................... 4

reversum, Platyceras ......................... 85

subelegans, Platyceras ....................... 85
INDEX 111

Page

subrotundum, Platyceras ........... 12,20,85;pl.8

Platyceratacea .................................. 85

Platyceratidae .................................. 85

Platyostoma inornatum .......................... 87

Platyteichum ............................. 2,51,56,57

Platyzona sp ..................................... 5

Pleurotomaria carbonaria ........................ 86

iowensis .................................... 51

lirata ....................................... 69

mississippiensis .......................... 51,76

nauvooensis ................................. 76

nevadensis ............................... 66,77

nodimarginata ........................... 22,67

nodomarginata ........................... 68,69

Stella ....................................... 58

textiligera ................................ 51,76

undulata ................................... 69

sp .... ...................................... 3

(Cycloni'.ma) strigillata ....................... 75

Pleurotomariacea ............................ 21,45

Pleurotomariidae ................................ 50

polita, Bellazona ...................... 1,11,14,15,17

23,S7,98;pl.9 

Portlockiella ..................................... 3

Present investigation ............................. 6

Previous work ................................... 3

Productus brazerianus ............................ 4

Promourlonia ................................... 54

proutana, Anematina ......................... 87,97

Pseudobaylea ................................... 51

(Pseudobaylea), Mourlonia ....................... 51

Pseudozygopleura ........................... 97;pl.9

lauta ....................................... 23

repenningi .................................. 23

sp .......................................... 25

(Pseudozygopleura) ........................ 8,91

lauta .................... 18,20,25,92,93;pl.9

repenningi ............... 20,25,91,92,93;pl.9

sp ............................. 6,12,93;pl.9

(Stephanozyga) ............................ 8,93

claviger .................... 16,17,25,93;pl.9

sp ....................................... 6

(Pseudozygopleura), Palaeostylus .................. 4

ianthinopsis, Palaeostylus ..................... 6

Pseudozygopleura ......................... 8,91

lauta, Pseudozygopleura ...... 18,20,25,92,93;pl.9

repenningi, Pseudozygopleura ....... 20,25,91,92,

93;pl.9 

sp., Pseudozygopleura ............... 6,12,93;pl.9

Pseudozygopleuridae ............................ 91

Ptychomphalides ............................. 50,52

Ptychomphalina .................. 50,51,53,70;pls.3,4

angulata ................................. 54,55

burbankensis ................. 20,23,24,54,71;pl.3

magna ................................... 54,55

sp ................................ 5,8,24,55; pl.4

Ptychomphalinae ................................ 50

Ptychomphalinides .............................. 53

Ptychomphalininae .............................. 50

Ptychomphalus ................................ 8,50

depressus ................................... 52

fountai nensis ................................ 52

sinuatus ................................. 52,58

wortheni .................................... 52

pulcherrimum, Platyceras ........................ 85

pygmaea, Girtyspira ............................. 98

quadrigatum, Glabrocingulum .............. 1,5,20,32

Glabrccingulum

(Glabrocingulum) ......... 5,11,12,13,14,

15,20,21,22,25, 

58,59,67, 

62;pls.5,6

R

randolphensis, Euphemites .................... 30,31

Raphistomatidae ................................ 46

References ..................................... 104

Register of localities ............................. 99

regularis, Soleniscus (Macrocheilus) .............. 96

Page

Trepospira (Angyomphalus) ....... 8,22,23,46; pl.3

reloba, Moulonia ............................. 51,54

remex, Naticopsis ................................ 88

Planospirina ................................ 88

repenningi, Pseudozygopleura .................... 23

Pseudozygopleura

(Pseudozygopleura) ......... 20,25,91,92,

93;pl.9 

reticulata, Bucanopsis (Retispira) ............. 2,39,40

reticulatus, Bellerophon ........................ 2,40

Ianthinopsis ................................ 94

Retispira ........................ 1,3,6,7,8,22,37; pl.2

albapinensis .............................. 5,39

barquensis .................................. 39

beedia ...................................... 39

cincta ........................ 11,14,19,22,23,39,

47,43,44;pl.2 

eliasi ................................ 2,39,40,42

jensenensis .................... 15,20,22,25,39,41

43,44;pl.2 

lineolata .................................... 39

michiganensis ............................ 39,42

minima ................................ 39,41,44

missouriensis ............................... 39

monroensis .............................. 39,41

nolani ......................... 5,11,14,20,21,22

25,39,43,44;pl.2 

ordinata ...................... 20,21,22,24,39,47,

43,44;pl.2 

ornata ................................... 39,42

perelegans .................................. 39

stenopsis ..................... 20,22,26,39,43; pl.2

textilis .......................... 4,8,22,23,39,40,

42,44;pl.2 

waverliensis .............................. 39,41

sp ................................ 19,43,45;pl.2

sp. indet ............................. 6,17,21,25

(Retispira) reticulata, Bucanopsis ............. 2,39,40

textilis, Knightites ........................... 44

sp.A, Knightites ............................. 32

reversum, Platyceras (Platyceras) ................. 85

Rhineoderma ............................... 8,45,56

dinglense ................................. 3,56

pealeanum ................................ 3,45

piasaense ................................... 56

sp ...................................... 8,23,45

Rhipidomella nevadensis ................. 19,21,26,66

Rhipidomella nevadensis Zone ............... 17,18,25

Richardsonites merriami ............ 1,12,19,21,26,84

Richardsonites merriami bed ..................... 15

Richardsonites merriami Zone ................. 22,23

roberti, Straparollus (Euomphalus) ............... 82

rockymontana, Anematina ....................... 87

rudilirata, Catazona ................. .1,5,11,16,17,23,

25,78;pl.7 

Ruedemanninae ................................. 75

rugiosiuscula, Sinuitina (Vorticina) ............ 28,29

rugosiusculus, Bellerophon .................. 28,29,34

taeniatus, Bellerophon ....................... 29

sablei, Lunulazona ................ 13,15,22,26,68,71

72,73;pl.4 

Mourlonia .................................. 68

sacajawensis, Euphemites ........... 6,11,20,22,25,26

30,32,33;pl.2 

sadlicki, Lunulazona ............. 1,5,11,20,22,24,55,

68,70;pl.4 

Schwedigonia ................................... 53

scissilis, Bellerophon (Bellerophon) ............ 34,35

scotti, Bellerophon ............................... 34

sedaliensis, Euphemites ....................... 30,32

seminudum, Glabrocingulum

(Ananias) ............... 5,19,20,21,22,26,32,

63,64,65,66; pl.6 

(Serpulospira), Straparollus ...................... 82

similis, Straparollus ............................. 82

Straparollus (Euomphalus) ................... 82

sinuata, Baylea .................................. 49

Page

sinuatum, Glabrocingulum (Glabrocingulum) ...... 58

sinuatus, Ptychomphalus ...................... 52,58

Sinuitidae ...................................... 27

Sinuitina .............................. 3,22,27;pl.l

anneae ................................... 2,28

cordiformis ................................. 28

keytei ....................................... 28

(Sinuitina) ................................ 82?

crispa ................... 15,22,23,27,29;pl.l

nudidorsa .............................. 27

venata ............................... 27,29

(Vorticina) ............................... 2,8,25

anneae .............................. 28,29

cyrtolites ................................ 28

keytei ................................... 29

rugiosiuscula ........................ 28,29

taeniata ................................ 28

vortex ....................... 8,22,23,2S;pl.l

(Sinuitina), Sinuitina .......................... 8,27

crispa, Sinuitina ............. 15,22,23,27,29;pl.l

nudidorsa, Sinuitina ........................ 27

venata, Sinuitina ......................... 27, 29

Sinuopeidae ..................................... 45

Skunk Spring section ............................ 75

Soleniscinae .................................... 94

Soleniscus ................................ 8,96;pl.9

glaber ................................... 96,97

sp. ................................ 4,6,16,25,96

sp.A .............................. 20,25,96;pl.9

sp.B .......................... 13,16,18,19,20,25

97;pl.9 

sp. indet .................................... 96

(Macrocheilus) regularis ..................... 96

solida, Mourlonia ............................... 51

speciosa, Worthenia .............................. 75

spergenensis, Bellerophon (Bellerophon) ...... 34,35,36

Euomphalus ................................. 3

sphaerulata, Trepospira (Trepospira) ........... 47,48

Spiroraphella ................................... 54

Spiroscala .................................... 3,53

splendens, Naticopsis (Naticopsis) ............. 87,88

Strophostylus ............................... 86

springerensis, Phymatopleura .................... 78

springeri, Lunulazona ........................... 68

Neilsonia ................................... 68

Stegocoelia ................................ 4,79;pl.9

sp .......................................... 23

(Stegocoela), Stegocoelia ....................... 8,79

(Hypergonia) ................................ 80

(Stegocoelia) .............................. 8,79

illionoiensis ............................. 80

kentuckiensis ............................ 80

okawensis ............................... 80

sp .......................... ll,20,25,SO;p/.9

illinoiensis, Stegocoelia ...................... 80

kentuckiensis, Stegocoelia .................... 80

okawensis, Stegocoelia ....................... 80

sp, Stegocoelia ................. 11,20,25^0; pl.9

Stella, Glabrocingulum (Glabrocingulum) ......... 58

Pleurotomaria ............................... 58

stellaeforme, Glabrocingulum

(Glabrocingulum) .................... 58,63

stellaeformis, Baylea [Trepospira] ................. 58

Mourlonia ............................... 46,58

stenopsis, Retispira ............... 20,22,26,39,43; pl.2

(Stephanozyga), Pseudozygopleura .............. 8,93

claviger, pseudozygopleura ...... 16,17,25,93; pl.9

sp., Pseudozygopleura ......................... 6

stinesvillensis, Ianthinopsis ...................... 94

Straparollus .............................. 82;pls.3,8

planus ...................................... 82

similis ...................................... 82

(Amphiscapha) ........................... 82,83

(Cylicioscapha) .............................. 82

(Euomphalus) ..................... 6,8,23,S2;pl.8

angularis ............................... 82

boonensis ............................... 82

brooksensis .......................... 82,83

exortivus ................................ 82

illinoisensis .......................... 82,84
112 LATE MISSISSIPPIAN GASTROPODS OF THE CHAINMAN SHALE, WEST-CENTRAL UTAH

Page

intermedius .............. 1,5,6,11,13,14,15,16,17,

18,19,20,23,25,82,53,84;pl.3 

latus ....................................... 82

multistriatus ................................ 82

nodibasis ............. 5,ll,16,17,23,25,S2,84;pl.3

nodosus .................................... 83

obtusus ..................................... 82

pancakensis ............................. 5,82,84

pernodous .................................. 83

planodorsatus ............................ 82,83

roberti ...................................... 82

similis ...................................... 82

subplanus .................................. 82

subrugosus .................................. 4

subsulcatus ................................. 84

trica.rina.tus ............................... 3,82

utahensis ................................... 82

xylacus ................................. 6,82,84

sp ................................. 21,23,S4;p.8

(Philoxene) ...................................... 82

(Phymatifer) .................................... 82

(Serpulospira) ................................... 82

(Straparollus) ................................. 3,82

striatulum, Platyceras (Orthonychia) ............... 3

gracile, Platyceras (Orthonychia.) .............. 3

strigillata, Pleurotomaria (Cydonema) ........ 75

Vforthenia .................................. 75

Strophostylus ........................... 6,8,S6;pl.8

chesterensis ................................. 86

nevadensis ........... 5,ll,16,17,18,25,27,«6,-pl.8

splendens ................................... 86

tantillus .................................. 5,86

wortheni .................................... #6

sturgeoni, Euconospira ........................ 73,74

subcorpulentus, lanthinopsis .................. 94,97

subelegans, Platyceras (Platyceras) ................ 85

subglobosus, Euphemites ...................... 30,32

sublaevis, Bellerophon (Bellerophon) ........... 34,35

subplanus, Straparollus (Euomphalus) ............ 82

subrotundum, Platyceras ......................... 85

Platyceras (Platyceras) ............. 12,20,S5;pl.8

subrugosus, Straparollus (Euomphalus) ............ 4

subscalaris, Worthenia ........................... 75

subsulcatus, Straparollus (Euomphalus) ........... 84

Subulitacea ..................................... 94

Subulitidae ..................................... 94

Subulitinae ..................................... 94

suturicompta, Naticopsis ...................... 87,88

Naticopsis (Naticospis) .................... 87,88

Systematic paleontology ......................... 27

tabulata, Worthenia ............................. 75

taeniata, Sinuitina (Vorticina) .................... 28

taeniatus, Bellerophon rugosiusculus .............. 29

Taeniospira ..................................... 50

tantillus, lanthinopsis ........................... 94

Strophostylus ............................. 5,86

tenuilineata, Vforthenia ...................... 5,23,76

Vforthenia (Yochelsonospira) ....... 5,11,13,14,18,

20,21,25,76;pl.7 

tenuilineatum, Loxonema ........................ 90

texanum, Cinclidonema .......................... 86

textiligera, Mourlonia .......................... 51,52

Pleurotomaria ............................ 51,76

Worthenia .................................. 75

textillis, Bellerophon ............................. 44

Knightites (Retispira) ........................ 44

Retispira ....................... 4,8,22,23,39,40,

42,44, pl.2 

textus, Mourlonia ................................ 51

thomasi, Worthenia .............................. 76

Worthenia (Yochelsonospira) ................. 77

Trepospira ............................... 22,46;pl.3

depressa .................................... 48

(Angyomphalus) .......................... 3,8,46

discus .................................. 47

excavata ................................ 47

excavatus ............................. 6,46

kentuckiensis ......................... 46,52

penelenticulata ........................... 46

regularis ..................... 8,22,23,46,-pl.3

(Trepospira) .............................. 8,47

tecom ..................... 20,22,24,47;pl.3

chesterensis .......................... 47,58

diadema ................ 5,13,14,18,20,21,22,

25,26,45; pl.3 

discoidalis ........................... 48,57

illinoiensis ........................... 47,48

minima .............................. 47,48

sphaerulata .......................... 47,48

sp ........................ 5,ll,22,24,49;pl.3

(Trepospira), Trepospira ....................... 8,47

tecom, Trepospira .............. 20,22,24,47, pl.3

chesterensis, Trepospira ................... 47,58

diadema, Trepospira ...... 5,13,14,18,20,21,22,25,

26,4«;pl.3 

discoidalis, Trepospira .................... 48,57

illinoiensis, Trepospira .................... 47,48

minima, Trepospira ...................... 47,48

sphaerulata, Trepospira ................... 47,48

sp., Trepospira ................ 5,ll,22,24,49;pl.3

[Trepospira] inflata, Baylea ...................... 58

stellaeformis, Baylea ......................... 58

tricarinatus, Straparollus (Euomphalus) ........ 3,82

trifibra, Baylea .................................. 49

Tropidostropha .................................. 50

Tumulites varians ............................... 77

turbiniformis, Euconospira ....................... 73

Turbonellininae ................................. 45

Turbonitella biserialis ............................ 5

Type and type lot ................................ 7

Type Chesterian section ......................... 23

U

ulrichi, Bellerophon ............................. 34

undulata, Pleurotomaria ......................... 69

uninodocarinata, Murchisonia .................... 67

Utah .............................................5

utahensis, Lunulazona ............... 12,15,22,68,71,

73,91;pl.4 

Straparollus (Euomphalus) ................... 82

varians, Tumulites .............................. 77

variata, Naticopsis (Naticopsis) ................... 87

vasulites, Bellerophon ............................ 33

uenata, Sinuitina (Sinuitina) .................. 27,29

venusta, Mourlonia ................ 8,23,51,52,54;pl.4

Palaeozygopleura ............................ 91

vespertinus, Bellerophon

(Bellerophon) ............ 1,5,11,14,16,18,19,

20,22,25,26,34,36-, 37;pl.l 

vinculatus, Bellerophon .......................... 34

vittatus, Euphemites .......................... 29,32

vortex, Sinuitina (Vorticina) ........... 8,22,23,2S;pl.l

(Vorticina), Sinuitina ......................... 2,8,25

anneae, Sinuitina ........................ 28,29

cyrtolites, Sinuitina .......................... 28

keytei, Sinuitina ............................. 29

rugiosiuscula, Sinuitina .................. 28,29

taeniata, Sinuitina .......................... 28

vortex, Sinuitina ................. 8,22,23,25/pl.l

W

waterlooensis, Euconospira .................... 73,74

Naticopsis (Naticopsis) .................... 87,88

waverliensis, Bucanopsis ......................... 39

Retispira ................................ 39,41

Wellergyi ..................................... 2,56

brazerianus .................................. 3

chesterensis ................................. 56

welleri, Neilsonia ............................ 5,67,68

Palaeozygopleura ............................ 91

welshi, Bellerophon (Bellerophon) ..... 13,21,22,25,34,

36,48;pl.l 

whitfieldi, Bulimorpha ........................... 94

whittleseyi, Bellerophon .......................... 35

Woolnoughia .................................... 51

(Woolnoughia), Mourlonia ....................... 51

worthenanus, Macrochilina ....................... 97

wortheni, Dictyotomaria .......................... 78

Loxonema ................................... 91

Ptychomphalus .............................. 52

Strophostylus ............................... 86

Worthenia ............................. 6,66,75;pl.7

castelmanensis .............................. 75

longi ....................................... 15

marcouiana ................................. 75

mississippiensis ............................. 76

nouuooensis ................................. 76

northviewensis .............................. 76

speciosa ..................................... 75

strigillata ................................... 75

subcalaris .................................. 75

tabulata .................................... 75

tenuilineata ............................. 5,23,76

textiligera ................................... 75

thomasi ..................................... 76

(Worthenia) ................................. 75

(Yochelsonospira) ..................... 5,8,75,76

mississippiensis ......................... 77

nauvoensis .............................. 77

northviewensis .......................... .77

pagoda ................................. 77

tenuilineata ................ 5,11,13,14,18,20,

21,25,76Vpl.7 

thomasi, ................................ 77

(Worthenia), Worthenia ...................... 75

Wyoming .................................... 5

xylacus, Straparollus (Euomphalus) ....... 6,82,84

yandellanum, Loxonema ..................... 90

yochelsoni, Dictyotomaria .................... 78

Yochelsonospira ............................. 75

pagoda ................................. 76

(Yochelsonospira), Worthenia ....... 5,8,75,76

mississippiensis, Worthenia .......... 77

nauvooensis, Worthenia .............. 77

northviewensis, Worthenia ........... 77

pagoda, Worthenia .................. 77

tenuilineata, Worthenia .... 5,11,13,14,18,

20,21,25,76;pl.7 

thomasi, Worthenia .................. 77

Yunnania ................................ 4

yvanii, Baylea ........................... 49

ziczac, Naticopsis (Naticopis) ................. 87
PLATES 1-9

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

Survey Library, Federal Center, Denver, CO 80225.
PLATE 1

FIGURES 1 6. Sinuitina (Sinuitina) crispa n. sp. (p.27).

1. 3. Ventral views (x 4) of two incomplete paratypes 

(USNM 210919, 210920) from USGS colln. 25261- 

PC, Skunk Spring section, Confusion Range.

2. 6. Side and ventral views (x 11/2) of holotype (USNM

210915) from USGS colln. 22961-PC, near Pogues 

Station ruins, Pancake Range, Nev. 

4, 5. Side and ventral views (x 1V2) of paratype (USNM

210916) from same collection as holotype. 

7-11. Sinuitina (Vorticina) vortex n. sp. (p.28).

7, 8, 11. Side (x 11/2), oblique (x 4), and ventral (x 1V2) views of 

paratype (USNM 210922) from USGS colln. 17018- 

PC, Granite Mountain section. 

9, 10. Side and ventral views (x 2) of holotype (USNM

210921) from same collection. 

12-14. Bellerophon (Bellerophon) welshi n. sp. (p.36).

Side, apertural, and abapertural views (x 1V2) of holotype (USNM

210928) from USGS colln. 17310-PC, Burbank Hills. 

15-17, 21-23. Bellerophon (Bellerophon?) sp. A (p. 37).

15, 16. Apertural and abapertural views (x 2) of specimen 

(USNM 211085) from USGS colln. 25275-PC, Foote 

Range.

17. Oblique view (x 1) of fragment (USNM 211086) showing raised selenizone, from same collection. 

21-23. Side, apertural, and abapertural views (x 5) of small 

specimen (USNM 210935) from USGS colln. 22883- 

PC, Foote Range. 

18-20. Bellerophon (Bellerophon) needlensis n. sp. (p. 37).

Side, opposite side, and apertural views (x 1) of holotype (USNM

210930) from USGS colln. 15160-PC, Needle Range.

24-26. Bellerophon (Bellerophon) vespertinus Gordon and Yochelson (p. 36 ). 

Side, apertural, and abapertural views (x 2) of specimen (USNM 

210934) from USGS colln. 17087-PC, Granite Mountain section. 

27, 28. Euphemites sp. B (p. 33 ).

Abapertural and side views (x 3) of specimen (USNM 210927) from 

USGS colln. 17018-PC, Granite Mountain section.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 1

14

27 ^^^^ 28

SINUITINA, BELLEROPHON, EUPHEMITES
PLATE 2

FIGURES 1-4. Euphemites sp. A (p. 32 ).

1, 2. Side and abapertural views (x 2) of specimen (USNM

210925) from USGS colln. 22880-PC, Conger Range. 

3, 4. Side and abapertural views (x 4) of small specimen (USNM

210926) from USGS colln. 17189-PC, Jensen Wash section, Burbank Hills. 

5, 6. Euphemites nevadensis Gordon and Yochelson (p. 32).

Abapertural and side views (x 2) of a specimen (USNM 211078) from

USGS colln. 25547-PC, Jensen Wash section, Burbank Hills. 

7, 8. Retispira sienopsis n. sp. (p.43).

Side and abapertural views (x 2) of holotype (USNM 210947) from USGS

colln. 17217-PC, Jensen Wash section, Burbank Hills. 

9-11. Euphemites cracens n. sp. (p. 31).

Abapertural, side, and apertural views (x 3) of holotype (USNM 210923)

from USGS colln. 22883-PC, Foote Range. 

12, 13. Retispira jensenensis n. sp. (p. 43 ).

Abapertural and side views (x 4) of holotype (USNM 210946) from USGS

colln. 17188-PC, Jensen Wash section, Burbank Hills. 

14, 15. Euphemites saeqjawensis C. C. Branson (p. 32).

Abapertural and side views (x 2) of specimen (USNM 210932) from

USGS colln. 17217-PC, Jensen Wash section, Burbank Hills. 

16, 17. Retispira sp. (p. 45 ).

Abapertural and side views (x 5) of specimen (USNM 210953) from

USGS colln. 22880-PC, Conger Range. 

18-21. Retispira nolani Gordon and Yochelson (p. 43).

18, 19. Side and abapertural views (x 3) of incomplete specimen 

(USNM 210951) from USGS colln. 17189-PC, Jensen 

Wash section, Burbank Hills.

20, 21. Abapertural view (x 4) and side view (x 2) of specimen 

(USNM 210952) from USGS colln. 17310-PC, Burbank 

Hills. 

22-29. Retispira ordinata n. sp. (p. 41).

22, 27, 28. Abapertural, side, and apertural views (x 2) of a small 

paratype (USNM 210941) from USGS colln. 17187-PC, 

Jensen Wash section, Burbank Hills.

23-26, 29. Abapertural, side, opposite side, and apertural views (x 2) 

and posterior view (x 4) of holotype (USNM 210940) from 

USGS colln. 17194-PC, from same locality. 

30, 31, 36. Retispira cf. R. textilis (Hall) (p. 44).

Side and abapertural views (x 2) and larger side view (x 4) of specimen 

(USNM 210936) from USGS colln. 17018-PC, Granite Mountain 

section. 

32-35. Retispira cincta n. sp. (p. 41).

Posterior view (x 4) and apertural, side, and abapertural views (x 3) of 

holotype (USNM 210937) from USGS colln. 17012-PC, Granite 

Mountain section.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 2

32

EUPHEMITES, RETISPIRA
PLATE 3

FIGURES 1-5, 7-10. Straparollus (Euomphalus) intermedius Gordon and Yochelson (p. 83).

1 3. Apical, abapertural, and basal views (x 2) of typical specimen (USNM 210954) from USGS colln. 17023-PC, Foote 

Range. 

4, 5. Apical and apertural views (x 2) of specimen (USNM

210955) from same collection.

7 10. Apertural, apical, abapertural, and basal views (x 2) of less 

rugose specimen (USNM 210957) from USGS colln. 

22880-PC, Conger Range. 

6, 11 17. Straparollus (Euomphalus) nodibasis n. sp. (p.82 ).

6, 11. Basal and abapertural view (x 1V2) of incomplete paratype 

(USNM 210960) from USGS colln. 17098-PC, Granite 

Mountain section.

12, 13. Apical and abapertural views (x 1) of large paratype 

(USNM 210959) from USGS colln. 15358-PC, Skunk 

Spring section, Confusion Range.

14-17. Apical, abapertural, basal, and apertural views (x 4) of 

holotype (USNM 210958) from USGS colln. 15355-PC, 

Skunk Spring Section, Confusion Range. 

18. Trepospira (Trepospira) sp. (p.49).

Oblique apical view (x 1V2) of unique crushed specimen (USNM 211027)

from USGS colln. 28628-PC, Granite Mountain section. 

19-26. Trepospira (Angyomphalus) regularis n. sp. (p.46 ).

19, 23, 24. Apical, basal, and abapertural views (x 5) of small 

paratype (USNM 210962) from USGS colln. 17018-PC, 

Granite Mountain section. 

20 22. Abapertural, apical, and basal views (x 2) of holotype

(USNM 210961) from same collection. 

25, 26. Apical and basal views (x 2) of another paratype (USNM

210963) from same collection. 

27-31. Trepospira (Trepospira) baconi n. sp. (p. 47 ).

Abapertural view (x 3) and oblique, apical, abapertural, and basal views 

(x 11/2) of holotype (USNM 210966) from USGS colln. 25264-PC, 

Jensen Wash section, Burbank Hills. 

32-36. Trepospira (Trepospira) diadema n. sp. (p. 48 ).

32, 33. Apical and abapertural views (x 2) of holotype (USNM 

210970) from USGS colln. 17310-PC, Burbank Hills.

34. Basal view (x 3) of another paratype (USNM 210971) from 

same collection.

35. Apertural view (x 1V2) of paratype (USNM 210974) from 

USGS colln. 17188-PC, Jensen Wash section, Burbank 

Hills.

36. Oblique view (x 3) of fragment showing selenizone (USNM

210972) from USGS colln. 17310-PC, Burbank Hills. 

37-39. Ptychomphalina burbankensis n. sp. (p. 54 ).

Apical, side, and apertural views (x 2) of holotype (USNM 210978) from 

USGS colln. 17201-PC, Jensen Wash section, Burbank Hills.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 3

STRAPAROLLUS, TREPOSPIRA, PTYCHOMPHALINA
PLATE 4

FIGURES 1-4, 16, 17. Lunulazona utahensis n. sp. (p.71).

1-4. Apical, apertural, abapertural, and basal views (x 3) of 

holotype (USNS 211010) from USGS colln. 20443-PC, 

Foote Range. 

16, 17. Apical and abapertural views (x 3) of paratype (USNM

211012) from USGS colln. 17022-PC, same locality. 

5 11, 15. Euconospira 'desereti n. sp. (p. 73 ).

5-7. Apical, apertural, and basal views (x 3) of paratype (USNM 

211021) from USGS colln. 17217-PC, Jensen Wash section, Burbank Hills. 

8, 15. Oblique and apical views (x 3) of same specimen unwhitened to show color pattern. 

9 11. Apical, abapertural, and basal views (x 3) of holotype

(USNM 211020) from same collection. 

12-14. Euconospira gradilis n. sp. (p. 74 ).

Apical, abapertural, and basal views (x 3) of holotype (USNM

211023) from USGS colln. 22880-PC, Conger Range. 

18-20. Ptychomphalina sp. (p. 55 ).

Apical, abapertural, and basal views (x 2) of specimen (USNM 

134170) figured by Sadlick and Nielsen (1963) as Mourlonia sp. 

from their locality 7-1, in the Chainman Formation near Leppy 

Peak, Elko County, Nev. 

21-23. Lunulazona nodomarginata (McChesney) (p. 69).

21, 22. Apical and apertural views (x 4) of specimen (USNM 

211007) from USGS colln. 17018-PC, Granite Mountain 

section.

23. Enlarged abapertural view (x 4) of specimen (USNM 

14410) figured by Walcott (1884), from USGS colln. 655 

(Old Series). Diamond Peak Formation, conical hill near 

Eureka, Nev. 

24, 25, 34, 35. Lunulazona sadlicki n. sp. (p. 70).

24, 25. Apical and abapertural views (x 2) of holotype (USNM

134171) from Sadlick and Nielsen (1963) locality 7-1,

Chainman Formation near Leppy Peak, Elko County,

Nev.

34, 35. Basal and abapertural views (x 2) of paratype (USNM

134169) from same locality. 

26, 27. Lunulazona? aff. L.t sablei (Yochelson and Dutro) (p.72 ).

26. Apical view (x 6) of specimen (USNM 211015) from USGS 

colln. 15370-PC, R. merriami bed, Foote Range.

27. Abapertural view (x 9) of another specimen (USNM

211016) from same collection. 

28 30. Mourlonia venusta n. sp. (p. 52).

Apical, apertural, and basal views (x 2) of holotype (USNM 210976)

from USGS colln. 17018-PC, Granite Mountain section. 

31-33, 36. Lunulazona costata Sadlick and Nielsen (p. 70).

31 33, Apical, abapertural, and basal views (x 2) of specimen 

(USNM 211008) from USGS colln. 17015-PC, Granite 

Mountain section.

36. Abapertural view (x 4) of specimen (USNM 211007) from 

USGS colln. 17012-PC, Granite Mountain section.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 4

27^^V 30 ^^ kftS^ 33 36

LUNULAZONA, EUCONOSPIRA, PTYCHOMPHALINA, MOURLONIA
PLATE 5

FIGURES 1 9. Glabrocingulum (Glabrocingulum) confusionense n. sp. (p. 60 ).

1-3. Apical, side, and basal views (x 2) of holotype (USNM 210994) from

USGS colln. 17187-PC, Jensen Wash section, Burbank Hills. 

4 6. Apical, abapertural, and basal views (x 2) of paratype (USNM

210995) from same collection. 

7-9. Same views (x 2) of another paratype (USNM 210999) from USGS

colln. 23846-PC, same locality.

10 15. Glabrocingulum (Glabrocingulum) quadrigatum Sadlick and Nielsen (p. 61 ). 

10-12. Apical, apertural, and basal views (x 3) of hypotype (USNM

211000) from USGS colln. 17310-PC, Burbank Hills. 

13 15. Apical, abapertural, and basal views (x 4) of another hypotype

(USNM 211001) from same collection. 

16-27. Glabrocingulum (Glabrocingulum?) hosei n. sp. (p. 65 ).

16-19. Apical, apertural, abapertural, and basal views (x 1 Va) of holotype 

(USNM 210990) from USGS colln. 25264-PC, Jensen Wash section, Burbank Hills. 

20-27. Same views (x 2) of two paratypes (USNM 210991, 210992) from

same collection.

28-35. Glabrocingulum (Glabrocingulum) binodosum Sadlick and Nielsen (p. 63 ). 

28 31. Apical, apertural, abapertural, and basal views (x 3) of a hypotype

(USNM 211059) from USGS colln. 22883-PC, Foote Range. 

32-35. Same views (x 4) of another hypotype (USNM 211004) from same 

collection.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 5

19 27 -^^^T 31 

GLABROCINGULUM
PLATE 6

FIGURES 1-3, 12. Glabrocingulum (Glabrocingulum) granulosum n. sp. (p. 59).

Apical, basal, and apertural views (x 2) and larger oblique view (x 4) of 

holotype (USNM 210984) from USGS colln. 17020-PC, Granite 

Mountain section. 

4-10. Glabrocingulum (Ananias) seminudum Gordon and Yochelson (p.66).

4-7. Apertural, apical, side, and basal views (x 4) of a specimen (USNM

211063) from USGS colln. 25319-PC, Burbank Hills. 

8-10. Enlarged apertural, apical, and basal views (x 2) of holotype 

(USNM 211060) from USGS colln. 23836-PC, Diamond Peak 

Formation, White Pine Range, Nev.

11. Glabrocingulum (Glabrocingulum) quadrigatum Sadlick and Nielsen, variant (p. 61). 

Abapertural view (x 2) of a hypotype (USNM 211002) from USGS colln.

17023-PC, Foote Range. 

13, 14. Glabrocingulum (Glabrocingulum) confusionense n. sp. (p. 60).

Oblique views (x 5) showing typical spires of two paratypes (USNM 

210997, 210998) from USGS colln. 15165-PC, Jensen Wash section, 

Burbank Hills. 

15. Glabrocingulum (Glabrocingulum) mephitifontis n. sp. (p.59).

Oblique view (x 5), showing details of spire of holotype (USNM 210988) 

from USGS colln. 15354-PC, Skunk Spring section, Confusion Range.

16. 19. Glabrocingulum (Glabrocingulum) quadrigatum Sadlick and Nielsen (p.61). 

Oblique views (x 5) of two hypotypes showing details of typical spire 

(USNM 211000, 211001) from USGS colln. 17310-PC, Burbank Hills.

17. 18. Glabrocingulum (Glabrocingulum) binodosum Sadlick and Nielsen (p. 63). 

Oblique views (x 4, x 5) of two hypotypes (USNM 211004, 211059) from 

USGS loc. 22883-PC, Foote Range.

20. Glabrocingulum (Glabrocingulum?) hosei n. sp. (p. 65).

Oblique view (x 4), showing details of spire of holotype (USNM 210990) 

from USGS colln. 25264-PC, Jensen Wash section, Burbank Hills.

21. Glabrocingulum (Glabrocingulum) sp. C. (p.64).

Apical view (x 3) of broken specimen showing sculptural details (USNM 

211006) from USGS colln. 15370-PC, Foote Range.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 6

GLABROCINGULUM
PLATE 7

FIGURES 1-5. Wortkenia (Yochelsonospira) tenuilineata Girty (p.76 ).

1, 2. Apical and side views (x 2) of well-preserved specimen (USNM

211018) from USGS colln. 17023-PC, Foote Range. 

3-5. Apical, apertural, and basal view (x 2) of another specimen

(USNM 211019) from USGS colln. 17310-PC, Burbank Hills. 

6-8. Glabrocingulum (Glabrocingulum) mephitifontis n. sp. (p. 59).

Apical, apertural, and basal views (x 3) of holotype (USNM 210988) from

USGS colln. 15354-PC, Skunk Spring section, Confusion Range. 

9 15. Deseretospira monilifera n. gen., n. sp. (p. 56 ).

9-12. Apical, apertural, basal, and oblique views (x 2) of holotype 

(USNM 210980) from USGS colln. 25264-PC, Jensen Wash section, Burbank Hills. 

13-15. Enlarged oblique, apertural, and basal views (x 2) of paratype

(USNM 210981) from USGS colln. 22857-PC, same locality. 

16, 17. Glabrocingulum (Glabrocingulum) sp. B (p. 64 ).

Apertural and apical views (x 3) of specimen (USNM 211005) from USGS

colln. 22880-PC, Conger Range. 

18-20. Cinclidonema sp. (p. 86 ).

Oblique apical, abapertural, and apertural views (x 1) of specimen (USNM

211026), from USGS colln. 28628-PC, Granite Mountain section. 

21. Glabrocingulum (Glabrocingulum) sp. A (p.63).

Adapertural view (x 3) of specimen (USNM 211004) from USGS colln.

17018-PC, Granite Mountain section. 

22-27. Catazona rudilirata Gordon and Yochelson (p.78 ).

22-24. Apical, apertural, and basal views (x 2) of silicified specimen 

(USNM 211024) from USGS colln. 17214-PC, Wallet Gulch section. 

25-27. Same views (x 2) of another silicified specimen (USNM 211025)

from same collection. 

28. Neilsonia sp. (p. 67 ).

Side view (x 5) of silicified specimen (USNM 348022) from USGS colln.

25252-PC, Granite Mountain section. 

29, 30. Baylea? sp. (p.49 ).

Abapertural and apertural view (x 4) of silicified specimen (USNM 211070)

from USGS colln. 25566-PC, Wallet Gulch section. 

31-33. Glabrocingulum (Ananias) nevadense (Walcott) (p.66).

Abapertural view (x 1), view showing details of spire (x 3), and apertural 

view (x 1) of lectotype (USNM 14110) from USGS colln. 651 (Old Series). 

Diamond Peak Formation at conical hill near Eureka, Nev. Included for 

comparison. 

34-36. Dictyotomaria?sp.(p.79).

Apical, apertural, and basal views (x 3) of silicified specimen (USNM 

211071) from USGS colln. 25566-PC, Wallet Gulch section.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 7

WORTHENIA, GLABROCINGULUM, DESERETOSPIRA, CINCLIDONEMA, 

CATAZONA, NEILSONIA, BAYLEA?, DICTYOTOMARIA?
PLATE 8

FIGURES 1-4. Platyceras (Platyceras) cf. P. (P.) subrotundwn Snider (p.85 ).

Side, abapertural, basal, and apertural views (x 2) of fairly well preserved specimen (USNM 211029) from USGS colln. 17059-PC, 

Jensen Wash section, Burbank Hills. 

5. Anematina sp. (p. 87).

Abapertural view (x 5) of a specimen (USNM 348024) from USGS

colln. 25260-PC, Foote Range. 

6-8. Strophostylus cf. S. nevadensis Gordon and Yochelson (p.86 ).

Apical, apertural, and abapertural views (x 4) of well-preserved specimen (USNM 211079) from USGS colln. 25252-PC, Granite Mountain section. 

9-12, 32, 33. Naticopsis (Jedria?) sp. (p. 90).

Apical, apertural, abapertural, and basal views (x 1), and apertural 

and apical views (x 2) of specimen (USNM 348026) from USGS 

colln. 25563-PC, Skunk Spring section, Confusion Range. 

13 18, 26. Naticopsis (Naticopsis) confusionensis n. sp. (p.88).

13-15, 26. Apical, apertural, and abapertural views (x 2) and larger 

apical view (x 4) of holotype (USNM 211030) from 

USGS colln. 20547-PC, Granite Mountain section. 

16-18. Apical, apertural, and abapertural views (x 2) of 

paratype (USNM 211031) from USGS colln. 17021- 

PC, Conger Spring area, Confusion Range.

19, 20, 25. Naticopsis (Naticopsis) cf. N. (N.) genevievensis Meek and Worthen 

(p. 89).

19, 25. Apical (x 3) and larger apical (x 5) views of incomplete 

immature paratype (USNM 211034) from USGS colln. 

15362-PC, Skunk Spring section, Confusion Range. 

20. Side view (x 2) of specimen (USNM 211033) from USGS 

colln. 15355-PC, Skunk Spring section, Confusion 

Range. 

21-24. Straparollus (Euomphalus) sp. (p.84).

Abapertural, apical, apertural, and basal views (x 1) of specimen

(USNM 348023) from USGS colln. 15161-PC, Needle Range. 

27, 28. lanthinopsis sp. B? (p.96 ).

Apical and abapertural views (x 2) of specimen (USNM 211053) from

USGS colln. 717208-PC, Jensen Wash section, Burbank Hills. 

30, 31. lanthinopsis sp. B (p. 95 ).

Abapertural view (x 3) and abapertural and apertural views (x 2) of 

specimen (USNM 211057) from USGS colln. 25551-PC, Foote 

Range. 

34-38. Naticopsis (Naticopsis?) clinovata n. sp. (p. 89 ).

34, 35. Apical and abapertural views (x 2) of holotype (USNM 

211074) from USGS colln. 25252-PC, Granite Mountain area.

36-38. Apical, abapertural and apertural views (x 2) of 

paratype (USNM 211035) from USGS colln. 15355- 

PC, Skunk Spring section, Confusion Range.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 8

30 31 iflr 32 *^^~ 33 ^^B^^^ 38 

PLATYCERAS, ANEMATINA, STROPHOSTYLUS, NATICOPSIS, STRAPAROLLUS, lANTHINOPSIS
PLATE 9

FIGURE 1. Pseudozygopleura(Pseudozygopleura) repenningi n. sp. (p. 92).

Side view (x 4) of holotype (USNM 211044) from USGS colln. 17209-PC, Jensen Wash section, Burbank Hills. 

2, 3. Pseudozygopleura (Stephanozyga) claviger n. sp. (p. 93).

2. Side view (x 2) of holotype (USNM 211045) from USGS colln. 15355-PC, Skunk Spring section, Confusion Range.

3. Side view (x 2) of paratype (USNM 211046) from same collection. 

4, 5. Bulimorpha sp. (p.94).

Abapertural and apertural views (x 4) of silicified specimen (USNM 211072) from USGS colln. 25566-PC, Wallet Gulch

section, Confusion Range. 

6, 7. Pseudozygopleura (Pseudozygopleura)? lauta n. sp. (p.92 ).

Abapertural views (x 4, x 8) of holotype (USNM 211042) from USGS colln. 17208-PC, Jensen Wash section, Burbank

Hills. 

8, 9. Meekospira? sp. (p. 98).

Abapertural and apertural views (x 2) of silicified specimen (USNM 211056) from USGS colln. 25566-PC, Wallet Gulch

section, Confusion Range. 

10. Meekospira sp. (p. 97).

View (x 3) of specimen (USNM 211055) from USGS colln. 25274-PC, Foote Range. 

11-15. Bellazona bella (Walcott) (p. 80).

11, 12. Abapertural and apertural views (x 3) of specimen (USNM 211037) from USGS colln. 17018-PC, Granite Mountain. 

13, 15. Side views (x 2, x 3) of holotype (USNM 14410) from USGS colln. 651 (Old Series). Diamond Peak Formation at

conical hill near Eureka, Nev. 

14. Abapertural detail (x 4) of holotype. 

16, 17. Stegocoelia (Stegocoelia) sp. (p. 80 ).

Views (x 5) of a specimen (USNM 211036) from USGS colln. 17209-PC, Jensen Wash section, Burbank Hills.

18. Pseudozygopleura (Pseudozygopleura)? sp. (p.92).

View (x 4) of unique specimen (USNM 348030) from USGS colln. 25252-PC, Granite Mountain section.

19. Indeterminate high-spired gastropod (p. 99).

View (x 3) of coarsely silicified slender shell (USNM 211069) from USGS colln. 25566-PC, Wallet Gulch section, Confusion

Range. 

20, 21. lanthinopsis? sp. (p. 96 ).

Abapertural and apertural views (x 3) of specimen (USNM 211051) from USGS colln. 17018-PC, Granite Mountain

section. 

22 25. Bellazona polita n. sp. (p. 81).

22. Abapertural view (x 3) of incomplete paratype (USNM 211040) from USGS colln. 17012-PC, Granite Mountain 

section.

23. Apertural view (x 3) of another paratype (USNM 211039) from same collection. 

24, 25. Side and apertural views (x 3) of holotype (USNM 211038) from same collection. 

26, 27. lanthinopsis sp. A (p.95 ).

Abapertural and apertural views (x 5) (aPosidonia is in the aperture, not an operculum) of specimen (USNM 211050) from

USGS colln. 15370-PC, Foote Range. 

28, 29. Girtyspira circumsecta n. sp. (p. 98).

Apertural and abapertural views (x 3) of holotype (USNM 348028) from USGS colln. 25271-PC, Skunk Spring section,

Confusion Range. 

30 33. lanthinopsis gandyensis n. sp. (p. 95).

30, 31. Apical and apertural views (x 5) of holotype (USNM 211047) from USGS colln. 22883-PC, Foote Range. 

32, 33. Abapertural and apertural views (x 3) of paratype (USNM 211048) from same collection.

34. Soleniscus sp. B (p. 97).

Abapertural view (x 5) of specimen (USNM 211054) from USGS colln. 17021-PC, Conger Mountain section, Confusion 

Range.

35. Soleniscus sp. A (p. 96).

Side view (x 2) of specimen (USNM 211052) from USGS colln. 17188-PC, Jensen Wash section, Burbank Hills.

36. Loxonema? sp. (p. 91).

View (x 4) of specimen (USNM 348025) with Anematina sp. from USGS colln. 25260-PC, Bishop Springs anticline, Foote 

Range.

37. Loxonema sp. (p. 91).

View (x 12) of specimen (USNM 348027) from USGS colln. 25558-PC, Granite Mountain.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1368 PLATE 9

PSEUDOZYGOPLEURA, BULIMORPHA, MEEKOSPIRA?, MEEKOSPIRA, BELLAZONA, 

STEGOCOELIA, lANTHINOPSIS?, lANTHINOPSIS, GIRTYSPIRA, SOLENISCUS,

LOXONEMA?, LOXONEMA