Early Pennsylvanian 

Ammonoids from 

Southern Nevada

GEOLOGICAL SURVEY PROFESSIONAL PAPER 613-C

Early Pennsylvanian 

Ammonoids from 

Southern Nevada

By MACKENZIE GORDON, JR.

CONTRIBUTIONS TO PALEONTOLOGY

GEOLOGICAL SURVEY PROFESSIONAL PAPER 613-C

Four species of late Morrow age 

characterize the Diaboloceras 

peroccidens Zone at the base of 

the Pennsylvanian sequence in 

Clark and Nye Counties

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1969
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

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

Washington, D.C. 20402 - Price 35 cents (paper cover)
CONTENTS

Abstract ________________

Introduction ______________

Acknowledgments _________

Ammonoid localities _____

Stratigraphic setting _______

Diaboloceras peroccidens Zone

Page

Cl 

1

1

2

3

Descriptive paleontology _ 

Syngastrioceras Librovitch, 1938 _ _ 

Bisatoceras Miller and Owen, 1937 . 

Diaboloceras Miller and Furnish, 1940 

Stenoprotwrites Schindewolf, 1934 __. 

References cited _______ ____ ______

Index ____________ ____ ____________

Pag-e

C4

10

11

13

ILLUSTRATIONS

	Page

FIGURE 1. Index map showing Lower Pennsylvanian ammonoid collecting localities ____________________---_--__--_ C2

2. Columnar sections at three ammonoid collecting localities ___________________ _____ ________ 3

3. Photographs of Syngastrioceras lanei n. sp ____._______________________________________ __ 5

4. Diagrams showing cross sections and suture of Syngastrioceras lanei n. sp ___ ___ __________ 5

5. Photograph of Syngastrioceras oblatum (Miller and Moore) ________________________ _ ______ 6

6. Diagram of external suture of Syngastrioceras oblatum (Miller and Moore) _______--__-___- _ -___ 6

7. Photographs of Bisatoceras nevadense n. sp ________________________________________________ 7

8. Diagrams showing cross sections and suture of Bisatoceras nevadense n. sp ____________------ __ 7

9. Photographs of Diaboloceras peroccidens n. sp ___.__________________________________________ 9

10. Diagrams showing cross sections and sutures of Diaboloceras peroccidens n. sp ____________________ 10

11. Photographs of Stenopronorites sp _________._____________________________________________ T.O

12. Diagram showing external suture of Stenopronorites sp ___________________________________ 11

III

CONTRIBUTIONS TO PALEONTOLOGY

EARLY PENNSYLVANIAN AMMONOIDS FROM SOUTHERN NEVADA

By MACKENZIE GORDON, JR.

ABSTRACT

Five species of ammonoids of late Morrow age are described from the basal part of the Pennsylvania!! sequence 

in the foothills of the Spring Mountains, northern Clark 

County, and at the Nevada Test Site, southern Nye County, 

Nev. Deposits of very late Mississippian and early Morrow 

age are absent in this region, where an unconformity is 

present between Upper Mississippian and Lower Pennsylvanian rocks. Species described are Syngastrioceras lanei 

n. sp., S. oblatum (Miller and Moore), Bisatoceras nevadense 

n. sp., Diaboloceras peroccidens n. sp., and Stenopronorites 

sp. Four of these species (the occurrence of Syngastriocerus 

oblatum being an isolated one) characterize the Diaboloceras 

peroccidens Zone, of middle late Morrow age. This fauna 

correlates with that of the middle part of the Bloyd Shale 

in the type section of the Morrow Series in northwestern 

Arkansas.

INTRODUCTION

Pennsylvanian ammonoids have been, until recently, virtually unknown in the far western United 

States. The discovery of a cephalopod fauna of late 

Morrow age in Clark and Nye Counties, Nev., was 

announced by Gordon and Poole in 1966. Previously, 

Poole, Orkild, Gordon, and Duncan (1965, p. A52) 

briefly noted a fauna indicative of an Early Pennsylvanian age from the Nevada Test Site.

The first of these ammonoids from southern Nevada was a worn specimen of Syngastrioceras oblatum (Miller and Moore). It was found in a small 

collection of fossils made by C. R. Longwell in 1952 

from the lower part of the Bird Spring Formation 

in Lucky Strike Wash, Spring Mountains, near Las 

Vegas. In the spring of 1957, Longwell and I examined this section but were unable to find the bed 

from which the ammonoid came nor did we discover 

any additional specimens.

A second find of Pennsylvanian ammonoids in 

southern Nevada came in 1961; P. P. Orkild, who

was mapping the Tippipah Spring quadrangle in the 

Nevada Test Site near Mercury, sent me crushed 

specimens of a schistoceratid resembling Branneroceras. Later that same year, Helen Duncan, F. G. 

Poole, Orkild, and I collected further specimens at 

the Nevada Test Site from Orkild's Red Canyon 

section and found additional ammonoids, including 

Bisatoceras, in the C. P. Hills. This resulted in the 

brief citation of this fauna in a paper (Poole and 

others, 1965, p. A52) on the age of the Eleana 

Formation. In 1964, F. A. McKeown's field mapping 

in the Yucca Lake quadrangle in the Nevada Tes4: 

Site provided an additional young specimen, cited 

as Boesites? in Poole, Orkild, Gordon, and Duncan 

(1965, p. A52), but now regarded as a young Stenopronorites.

In the fall of 1965, further studies in southern 

Nevada by Poole and me permitted recognition of 

this ammonoid assemblage over a wider area. The 

same fauna was found in Clark County at the north 

end of the Spring Mountains, a few miles west of 

Indian Springs. In the spring of 1966, N. Gary 

Lane provided additional material, which he had 

collected earlier that year at a locality just south 

of Indian Springs. Lane's material demonstrate? 

that the schistoceratid in this fauna is a primitive 

Diaboloceras.

ACKNOWLEDGMENTS

I would like to thank Prof. N. Gary Lane, University of California at Los Angeles, and Prof. G. D. 

Webster, San Diego State College, for their kindness in making their collection of Early Pennsylvanian ammonoids from the locality near Indian 

Springs available for study and deposit in the U.S. 

National Museum.

Cl
C2 CONTRIBUTIONS TO PALEONTOLOGY

AMMONOID LOCALITIES

The ammonoids come from nine collections made 

at five localities (fig. 1). Descriptions of the localities at which each collection was made are given in 

the locality register that follows figure 1 and the 

list of ammonoid fauna.

1

Nevada Test Site

\

N

NYE COUNTY

\

\

4>r

INYO COUNTY

0 10 20 30 

1 1 1 I

1

'

1

RED

CANYON

*'

C P \2

1

LINCOLN COUNTY

r I "

MercuryjX 

\CT 1 \ Indian Springs

/NDMN J_>»4 CLARK COUNTY

\

5 m LUCKY STRIKE

\

\

WASH

 * Las Vegas

\ 1

 MILES \ ( IARIZ.

1 V 1 V

FIGURE 1. Lower Pennsylvanian ammonoid collecting 

localities in southern Nevada.

O

1

00to 

to

X

0 0

1 1

US CO

US T|l

O C3

X X

O

PH

to 

to

o

X

9

O

PH

co

X

O 

PH 

1 (N

X

X

3

O

PH

us 

to

X

X

X

X

4

O

PH

0

o

CO 

CO

X

X

X

X

5

O

PH

us

COto*""

X

USGS

Locality

No.

Locality

in 

fig. 1

Locality register

Description and collectors

16315-PC 5 Charleston Peak 15-min quadrangle, Nev. 

Northwest of Lucky Strike Wash, 8 miles 

south of Tonopah Highway in SW 1^ sec. 30, 

T. 18 S., R. 58 E., Spring Mountains, Clark 

County, Nev. Bird Spring Formation, basal 

unit, within 75 ft. of base. Collector, C. R. 

Longwell, Aug. 4, 1952.

19668-PC 1 Tippipah Spring 7%-min quadrangle, Nev. Red 

Canyon, north side of Red Canyon drainage, 

Nevada Test Site, Nye County, Nev. [same 

as USGS Iocs. 20559-PC and 22435-PC]. 

Tippipah Limestone, lower 200 ft. Collector, 

P. P. Orkild, May 1960.

Locality register Continued

Description and collectors

USGS Locality

Locality in

No. fig. 1

20559-PC 1 Tippipah Spring 7 1/i2-min quadrangle, Nev. Red 

Canyon section, in northwest part of northern outlier of Syncline Ridge, on west slope 

and in southwest-trending drainage of the 

more western and lesser of two summits of 

hill 5203, about 1,700 ft due we?t of 5203 

summit (exactly 4 miles airline northeast 

of Tippipah Spring water tanks-), Nevada 

Test Site, Nye County, Nev. Tippipah Limestone, fossils from a 30-ft zone whose base 

is 30 ft above base of formation. Collectors, 

Mackenzie Gordon, F. G. Poole, P. P. Orkild, 

Helen Duncan, R. A. Lewandowsk', and R. D. 

Rieke, Aug. 16, 1962.

20562-PC 2 Yucca Lake 7 1/2 -min quadrangle, Nev. From 

window exposing Carboniferous formations 

beneath thrust plate in C. P. Hill?. 2% miles 

southwest of Yucca Pass in Area 6 of Nevada Test Site, on east slope of hill whose 

summit slightly exceeds 4,700 ft in elevation, 

Nye County, Nev. Lat 36°54'48" N.; long 

116°04'58" W. Tippipah Limestone, ammonoids from basal 2 ft. Collectors, Gordon, 

Poole, and others, Aug 17, 1962.

22071-PC 2 Yucca Lake 7%-min quadrangle, Nev. On east 

slope of C. P. Hills near head of main access 

wash, in window of Carboniferous1 rocks just 

below C. P. thrust. Lat 36°55'11" N.; long 

116°05'12" W., Nevada Test Site, Nye County, Nev. Tippipah Limestone, kwer 20 ft. 

Collector, F. A. McKeown, 1964.

22435-PC 1 Tippipah Spring 7%-min quadrangle, Nev. 

Same locality as 20559-PC and extending as 

far north as saddle on west slope of hill. 

Tippipah Limestone, lower 60 ft. Collectors, 

Gordon, Orkild, Poole, and J. W. Miller, 

Sept. 14, 1965.

22442-PC 2 Yucca Lake 7V2-min quadrangle, Nev. Same 

locality as 20562-PC, within 101 ft north 

along contact. Tippipah Limestone, basal 2 

ft. Collectors, Gordon, Poole, ?nd Miller, 

Sept. 16, 1965.

22465-PC 3 Las Vegas 2° sheet, Nev. Indian Springs area. 

Fossiliferous beds exposed in si allow saddle at head of southwest-trendinjr wash, 4% 

miles southwest of Indian Springs, probably 

in NW% sec. 31, T. 16 S., R. 56 E. (unsurveyed), Clark County, Nev. P?rd Spring 

Formation, 1 to 3 ft above base, Collectors, 

Gordon, Poole, and Miller, Sept. 19, 1965.

23300-PC 4 Las Vegas 2° sheet, Nev. Indian Springs area. 

Limestone bed exposed in bulldozer cut 

across Indian Springs-Bird Spr'ng contact 

at east end of hill exposing Bird Spring 

Formation, about 2 miles south rnd slightly 

east of Indian Springs, Clark County, Nev. 

Bird Spring Formation, 1 to 3 ft above base. 

Collectors, N. G. Lane and G. D. Webster, 

1966.
EARLY PENNSYLVANIAN AMMONOIDS FROM SOUTHERN NEVADA C3

STRATIGRAPHIC SETTING

Columnar sections for localities 1-3 (fig. 1) are 

shown in figure 2. It will be noted that the stratigraphic terminology for the Nevada Test Site (Iocs. 

1 and 2), Nye County, is different from that employed in Clark County on the south side of the Las 

Vegas lateral shear zone.

The Upper Mississippian-Lower Pennsylvania!! 

section in the Nevada Test Site is relatively simple. 

The Eleana Formation, Late Devonian to Late Mississippian in age, composed predominantly of shale 

with interbedded coarser clastic rocks, is overlain 

by the Tippipah Limestone, of Early Pennsylvanian 

age, which consists of intercalated massive and very 

thin bedded limestone. The upper part of the Eleana 

is composed of brown-weathering shale with some 

relatively thin intercalated sandstone and limestone 

beds and resembles the equivalent part of the 

Chainman Shale, farther northeast in the Great 

Basin.

Stratigraphically about 100 feet below the Mississippian-Pennsylvanian unconformity in the Rei 

Canyon section (loc. 1, fig. 1), ammonoids of the 

Cravenoceras merriami zone of late Chester age 

have been found (Gordon and Poole, 1966). Airmonoids of the family Schistoceratidae occur 

throughout the lower 140 feet of the Tippipah Limestone in the Red Canyon section. Although Diaboloceras peroccidens n. sp. is the only ammonoid known, 

at this locality, all specimens cannot be definitely 

assigned to this species because none have sutures 

preserved.

In the section in the C. P. Hills, the Pennsylvanian 

ammonoids are restricted to the basal part of the 

Tippipah Limestone; they all probably come from 

the basal 2-3 feet of the formation.

In the Indian Springs region at the north end cf 

the Spring Mountains, much of the section equivalent in age to the Eleana Formation is represented 

by a predominantly limestone sequence, the Monte

RED CANYON

EROSION

C. P. HILLS INDIAN SPRINGS

31 

|«5 Q-

-13 MILES- -35 MILESr 200 FEET

- 150

- 100

- 50

EXPLANATION

i i~~ 

-. I . I

i i

Quartzite, calcareous Argillite, calcareous Platy, shaly

i,______".

SANDSTONE SHALE

~° 'c E

 co o

Massive, cherty Sandy, conglomeratic

LIMESTONE

Of Webster and Lane (1967).

FIGURE 2. Columnar sections for ammonoid collecting localities 1-3, figure 1. Modified from Gordon and Poole (1968),
C4 CONTRIBUTIONS TO PALEONTOLOGY

Cristo Limestone of Mississippian (Kinderhook to 

Meramec) age. It is overlain unconformably by a 

Chainman-like shale unit which Longwell and Dunbar (1936) included in their Indian Springs Member, the Bird Spring Formation. In figure 2, the 

Indian Springs Formation is used in the sense of 

Webster and Lane (1967, p. 507-510), is restricted 

to that part of Longwell and C. 0. Dunbar's unit 

that lies below the Mississippian-Pennsylvanian unconformity, and is not included in the Bird Spring 

Formation.

The Bird Spring Formation, revised in this manner, begins at the same level as the Tippipah Limestone of the Nevada Test Site. The lithology of the 

two formations is similar, except that considerably 

more chert is present in the lower part of the Bird 

Spring Formation. A conglomerate about 1 foot 

thick marks the base of the Bird Spring Formation 

in the vicinity of Indian Springs and can be traced 

along the contact for several miles. The ammonoids 

occur immediately above this conglomerate through 

an approximately 2-foot zone of limestone that is locally an organic detritus.

In Lucky Strike Wash on the east side of the 

Spring Mountains (loc. 5, fig. 1), the Indian Springs 

Formation is absent, and the Bird Spring Formation 

rests unconformably on the Monte Cristo Limestone. 

The lower 50 feet of the Bird Spring Formation includes limestone beds crowded with poorly preserved 

coarsely silicified specimens of Rhipidomella nevadensis (Meek). The abundance of this brachiopod 

suggests a Late Mississippian age for the basal part 

of the Bird Spring Formation at this locality. Presumably the worn specimen of Syngastrioceras oblatum (Miller and Moore) came from a slightly higher 

level in the formation.

DIABOLOCERAS PEROCCIDENS ZONE

The four species found associated in the assemblage at the base of the Bird Spring Formation in 

northern Clark County and in the Tippipah Limestone in southern Nye County constitute the ammonoid assemblage that characterizes what I term 

the Diaboloceras peroccidens Zone. Whether the 

occurrence of Syngastrioceras oblatum (Miller and 

Moore) at Lucky Strike Wash should be referred to 

the same zone is not known at present. The Diaboloceras peroccidens assemblage has been found at localities as much as 48 miles apart. As these localities 

occur on both sides of the Las Vegas lateral shear 

zone and because displacement along this shear 

zone is believed to have approximated 30 miles 

(Gordon and Poole, 1966), the original distribution 

of this fauna was even greater than is now apparent.

The age of this zone can be determined vT ith reasonable accuracy by fitting Diaboloceras peroccidens 

n. sp. into the evolutionary pattern of the schistoceratids, as it is presently known. This Nevada 

species is the most primitive Diaboloceras known. 

It represents the next step beyond Branneroceras 

branneri (Smith), from the Brentwood Limestone 

Member at the base of the Bloyd Shale in northwestern Arkansas. The umbilical lobe of B. branneri has 

migrated onto the flanks to become a second lateral 

lobe in D. peroccidens n. sp. Diaboloceras peroccidens 

had not yet developed the tendency toward triangular coiling of the early whorls as in D. neumeieri 

Quinn and Carr from the Trace Creek Shale Member 

at the top of the Bloyd Shale in northeast A rkansas. 

Its stage of development places it in middle Bloyd 

time. Thus, the Diaboloceras peroccidens Zone would 

seem equivalent, at least in part, to the Axinolobus 

modulus zone of middle Bloyd age in northwest 

Arkansas, which occurs stratigraphically between 

the Branneraceras branneri and Diaboloceras neumeieri zones.

DESCRIPTIVE PALEONTOLOGY

Genus SYNGASTRIOCERAS Lihrovitch, 1938

Syngastrioceras lanei n. sp.

Figures 3A-D, 4A-C

Diagnosis. Syngastrioceras with involute subglobose to globose conch. First lateral lobe of suture 

of moderate width.

Description. Conch subglobose during much of 

growth, some individuals globose at diameters from 

18 to 26 mm, none seen in excess of 30 mm; involute, 

diameter of umbilicus normally equal to a Pttle less 

than one-third diameter of conch except during 

early growth when it is greater. Venter ard flanks 

gently convex, strongest rounding along ventrolateral zones; umbilical shoulder subangular; umbilical 

wall gently convex. First two whorls coiling planorbitally, widening rapidly in later whorls.

Shell surface appears smooth but has very fine, 

somewhat unequal, closely-spaced growth lirae that 

are radial at umbilical shoulder, form a shallow 

broad sinus over each flank, bow forward at each 

ventrolateral zone and are nearly straight or almost 

imperceptibly indented into faint sinus over venter; 

overall effect is of flat orad bow across venter. In 

addition, four to five fairly broad shallow internal 

varices that roughly follow the configuration of 

transverse lirae occur on each whorl. Longitudinal
EARLY PENNSYLVANIAN AMMONOIDS FROM SOUTHERN NEVADA C5

FIGURE 3. Syngastrioceras lanei, n. sp. A, B, Ventral and 

side views of holotype, USNM 161525, from USGS loc. 

22465-PC; C, D, side and ventral views of paratype, 

USNM 161526, from same locality. All views x 1.

sculpture is limited to a fairly strong cord along 

each umbilical shoulder.

Suture has been observed only at diameters less 

15 mm. At an estimated conch diameter of 10 mm 

(fig. 4C), suture has ventral lobe with hastate 

prongs, divided to about half its overall length by 

median sinus and having convex sides, slightly 

pinched in orad; first lateral saddle slightly narrower 

than ventral lobe, spatulate; first lateral lobe slightly 

wider and longer than ventral lobe, sides not evenly 

convex but each with subangulation near middle, 

acuminate; second lateral saddle rounding asymmetrically and curving very gently to umbilical 

shoulder; umbilical lobe short, acuminate. Internal 

suture consists of fairly symmetric short pointed 

lobes separated by slightly wider, faintly asymmetric 

saddles; dorsal lobe somewhat hastate; first lateral 

lobe more strongly hastate, with extended point.

USNM specimen

161527 161525 161528 161533 161526 161534 161630

Dimensions (mm)

Height of last whorl (H)_ 

Width of last whorl (W) 

Width of umbilicus (U) ___

28.5 

13.0

9.5

26.0 

14.0 

23.8 

7.8

19.5 

10.2 

18.0 

5.5

16.0 

8.0 

14.1 

5.2

15.9 

7.6 

14.3 

4.7

14.2 

6.8 

12.5 

5.3

5.6 

2.3 

4.7 

2.6

Proportions

U/D

W/D

W/H

0.33 

.86 

1.88

0.30 

.91 

1.70

0.28 

.95 

1.76

0.32 

.88 

1.76

0.30 

.90 

1.89

0.37 

.88 

1.83

0.47 

.86 

2.04

FIGURE 4. Cross sections and suture of Syngastrioceras 

lanei n. sp. A, B, cross sections X 1%, X 5 of paratype, 

USNM 161533 from USGS loc. 23300-PC; C, suture x4 

from paratype, USNM 161532, from same locality, where 

H = 4.7 and W = 10.5 mm.

1 Partly estimated.

Discussion. This species is represented by 27 

specimens from two localities near Indian Springs, 

Clark County. It has not been recognized in the 

Nevada Test Site, although it is associated in the 

basal Bird Spring Formation in Clark County with 

the same fauna that occurs in the basal Tippipah 

Limestone in Nye County.

Syngastrioceras lanei is a small subglobose to globose species having a single cord along the umbilical 

shoulder like that found in other species assigned 

to this genus. It differs from S. globosum (Easton), 

from the Hale Formation of northeast Arkansas, by 

being much more involute and having a first lateral 

lobe that is almost twice as wide as that of the Hale 

species.

The suture of S. lanei is very much like that of S. 

oblatum (Miller and Moore) at the same conch diameter, but the conch of S. lanei is wider and has a 

distinctly broader and flatter venter than S. oblatum. 

The configuration of the venter is somewhat like 

that of S. depressum Gordon, but that species is very 

evolute.

Types. Holotype, USNM 161525; paratypes, 

USNM 161526-161535, inclusive.

Occurrence. Bird Spring Formation, 1-3 feet 

above base, USGS loc. 22465-PC (USNM 161525- 

161531) and 23300-PC (USNM 161532-161535).

Syngastrioceras oblatum (Miller and Moore)

Figures 5, 6

1896. Gastrioceras globulosum (Meek and Worthen) Smith 

[part], Am. Philos. Soc. Proc., v. 35, no. 152, p. 258- 

260, pi. 18, figs, la-3, 5a-6b [not fig. 4]. Reprinted 

as Stanford Univ., Hopkins Seaside Lab., Contr. 

Biology, no. 9, p. 48-50, same pi. and figs.

1903. Gastrioceras globulosum (Meek and Worthen) Smith, 

U.S. Geol. Survey Mon. 42, p. 89, 90 [not pi. 6, fig. 1, 

pi. 21, figs. 7-9].

1938. Cravenoceras! morrowense Miller and Moore [part], 

Jour. Paleontolgy, v. 12, no. 4, p. 346, 347, pi. 43, 

fig. 1, text fig. 2B [not pi. 43, figs. 2, 3, text fig. 2A].
C6 CONTRIBUTIONS TO PALEONTOLOGY

1938. Glaphyrites oblatus Miller and Moore, Jour. Paleontology, v. 12, no. 4, p. 352, 353, pi. 43, figs. 10, 11, 

text fig. 3A.

1944. Cravenocerast morrowense Miller and Moore. Miller 

and Owen, Jour. Paleontolgy, v. 18, no. 5, p. 421, 

422, pi. 65, figs. 3, 4, pi. 66, figs. 3, 4, text fig. 2B.

1944. Glaphyrites oblatus Miller and Moore, Jour. Paleontology, v. 18, no. 5, p. 425-427, pi. 66, figs. 5-13, 

text fig. 4C.

1962. Cravenocerast morrowense Miller and Moore. Unklesbay, Oklahoma Geol. Survey Bull. 96, p. 59, 60, pi. 8, 

figs. 8, 9, text fig. 4.

1962. Glaphyrites oblatus Miller and Moore. Unklesbay, 

Oklahoma Geol. Survey Bull. 96, p. 87, 88, pi. 13, 

figs. 1-3, text fig. 6B.

1964 [1965]. Glaphyrites morrowensis (Miller and Moore). 

Gordon [part], U.S. Geol. Survey Prof. Paper 460, 

p. 223, 224, pi. 23, figs. 13 15, text figs. 59G, H, 60C 

[not pi. 23, figs. 19, 20, 30, 31, text fig. 60D].

1964 [1965]. Glaphyrites oblatus Miller and Moore. Gordon, 

U.S. Geol. Survey Prof. Paper 460, p. 224, 225, pi. 

23, figs. 3-5, 10-12, text figs. 5QA-D, 6GA.

A single worn specimen is referred to this species. 

At the time of the preparation of my report on the 

Arkansas Carboniferous cephalopods (Gordon, 

1964), this specimen was regarded as belonging in 

Glaphyrites morrowensis (Miller and Moore, as interpreted in that report). The types of Miller and 

Moore's species, which was described as Cravenocerast, were lost at that time and unavailable for 

study. Later they were found and have been reexamined by J. A. McCaleb in a study of the ammonoids of the Bloyd Shale. According to McCaleb 

(written commun., 1965), the two syntypes of 

Cravenocerasl morroivense figured by Miller and 

Moore. (1938) belong in different genera. One is the 

species that I described as Pygmaeoceras solidum 

Gordon. The other is an involute form of Syngas-

*l^cf^"'" c^r^'^KI 

FIGURE 5. Syngastrioceras 

oblatum (Miller and Moore), 

a unique worn specimen 

X 1, USNM 161524, from 

USGS loc. 16315-PC.

trioceras oblatum (Miller and Moore). McCaleb intends to designate one of them as the type of C.? 

morrowense Miller and Moore. McCaleb and I had 

independently reached the conclusion that Glaphyrites oblatus Miller and Moore should be referred to 

Syngastrioceras and not included in Glaphyrites. I 

further believe that Syngastrioceras oblatum (Miller and Moore) may be a junior synonym of Goniatites nolinensis Cox, but the holotype of the Kentucky species has been lost and I have not been able 

to locate a topotype and therefore hesitate to use 

Cox's name.

The specimen (fig. 5) is a phragmocone, slightly 

distorted in its coiling, one side of which is badly 

eroded. The surface of the internal mold is intact 

in some places; within the narrow umbilicus, the 

external surface of the umbilical shoulder is marked 

by a fairly strong cord. A reasonably well preserved 

external suture (fig. 6) is exposed a little less than 

one volution from the end. It has the configuration 

typical of sutures of S. oblatum at this diameter.

The dimensions of the specimen (in mm) are as 

follows: Diameter (D), 53; height of last whorl (H) , 

22.5; width of last whorl (W), 32, approximately; 

and width of umbilicus (U), 11. This gives the following proportions: U/D=0.21,W/D = 0.60, and 

W/H = 1.42.

Figured specimen. USNM 161524.

Occurrence. Bird Spring Formation, basal 75 

feet, USGS loc. 16315-PC, Clark County, Nev.

FIGURE 6. Suture of Syngastrioceras oblatum (Miller 

and Moore). X 1%, where 

D =: 33 (estimated), H = 

13, and W = 17 mm. From 

specimen shown in figure 5.

Genus BISATOCERAS Miller and Owen, 1937 

Bisatoceras nevadense n. sp.

Figures 7A-R, 8A-C

Diagnosis. Bisatoceras with approximately same 

shell shape as type species but differing in having 

less sinuous growth striae, narrower lobes in external suture, and a narrow open umbilicus.
EARLY PENNSYLVANIAN AMMONOIDS FROM SOUTHERN NEVADA C7

FIGURE 7. Bisatoceras nevadense n. sp. A-D, Side view X 1 and back, side, and front views X 1% of a paratype, USNM 

161540 from USGS loc. 23300-PC; E-H, back, side, and front views X 1V2, and side view X 1 of a paratype, USNM 

161546 from USGS loc. 20562-PC; I-K, side, front, and back views X 3 of immature paratype, USNM 161547 from 

same locality as E-H; L-O, side, back, opposite side, and front views X 1 of holotype, USNM 161536 from USGS loc. 

22465-PC; P-R, side, back, and front views X 2 of paratype showing inner whorl, USNM 161537, from same locality 

as L-O.

Description. Immature conch thick discoidal, 

becoming subdiscoidal with maturity, extremely involute; venter rather narrow, rounding evenly into 

flanks, which are slightly convex to flat and slope 

gently toward venter. Umblical shoulder broadly 

rounded; umbilical wall narrowly rounded; umbilicus 

narrow but open within small shallow funnel-shaped 

depressed area. Transverse section (fig. 8A, B) 

shows first two to three whorls planorbitally 

coiled, next two widening rapidly to thick discoidal 

conch with nearly closed umbilicus; very narrow. 

Shell attains subdiscoidal shape at diameters of 

30 mm and greater.

Conch ornamented by gently sinuous transverse 

growth striae that form moderately shallow sinus 

over umbilical shoulder, barely perceptible bow and 

sinus over flanks, deeper orad bow over ventrolateral 

shoulder, and shallow sinus over venter. Sinuousity 

less strong in immature stages so that transverse 

striae appear almost straight across flanks in some 

specimens. Transverse growth constrictions appear 

to be limited to no more than one per volution in 

immature shell.

External suture with very broad ventral lobe and 

rather narrow first lateral lobe (fig. 8C). Ventral 

lobe with two large prongs having convex sides and 

pointed tips, divided to a depth equal to about fourfifths of its overall length; first lateral saddle a 

little narrower than either prong of ventral lobe, 

rather narrowly rounded orad; first lateral lobe 

about as wide as first lateral saddle, asymmetrical in

that orad side is gently convex and dorsad side both 

concave and convex, tapering gracefully to moderately sharp point that reaches plane tangent to 

points of ventral lobe prongs; second lateral saddle 

shallow, broad, and slightly curved across inner 

flanks to umbilicus. Umbilical lobe short and broad. 

Internal suture includes three narrow lobes separated by narrow saddles and connected by wider, 

shallower saddle to umbilical lobe, but details cannot 

be observed on these specimens.

FIGURE 8. Cross sections and suture of 

Bisatoceras nevadense n. sp. A, B, Cross 

sections X 1*2, X 5 of paratype, USNM 

161541 from USGS loc. 23300-PC; C, 

external suture X 3 from paratype shown 

in figure 7A-D, where D = 17.0, H = 

10.0, and W = 10.3 mm.
C8 CONTRIBUTIONS TO PALEONTOLOGY

USNM specimen

161536 161540 161542 161541 161543 161544 161538

Dimensions (mm)

Diameter 

Height of 

Width of 

Width of

(D)

last whorl (H)__ 

last whorl (W) __ 

umbilicus (U) __

38.3 

22.7 

17.4 

3.3

18.2 

11.5 

10.9 

1.8

17.3 

10.7 

11.5 

1.7

13.2 

7.8 

8.0 

1.4

12.2 

7.6 

8.0 

1.3

5.3 

3.0 

3.5

.8

4.8 

2.9 

3.3 

1.2

Proportions

U/D

W/D 

W/H

0.08 

.43 

.76

0.10 

.60 

.95

0.10 

.63 

1.07

0.11 

.61 

1.03

0.11 

.66 

1.05

0.15 

.66 

1.17

0.25 

.69 

1.13

Discussion. Included in the type lot are 40 specimens from four collections. The type locally (loc. 3, 

fig. 1) is 4^ miles southwest of Indian Springs, but 

specimens from Lane's locality (USGS loc. 23300- 

PC) just south of Indian Springs (loc. 4, fig. 1) 

and the C. P. Hills in the Nevada Test Site (loc. 2, 

fig. 1) have been used in preparing this description.

Bisatoceras nevadense n. sp. has a shape much like 

that of the type species of the genus, B. primum 

Miller and Owen from beds of Late Pennsylvanian 

(Missourian) age in Oklahoma. A direct comparison 

with the topotypes of the Oklahoma species shows, 

however, that B. primum has a slightly narrower 

venter, slightly less depressed umbilical region, a 

closed umbilicus, slightly more sinuous transverse 

striae at the same diameter, and generally more 

closely spaced septa.

Two other species have been described from rocks 

of Morrow age, B. paynei Gordon and B. (Pseudobisatoceras) secundum -Miller and Moore. B. paynei 

has a more tumid shell than B. nevadense and transverse sculpture consisting of lamellae that are slightly raised along their orad edge as in Cravenoceras; 

the prongs of its ventral lobe are a little smaller 

than in B. nevadense. B. (Pseudobisatoceras) secundum differs in having longitudinal lirae on the surface of the conch.

Types. Holotype, USNM 161536; paratypes, 

USNM 161537-161548 inclusive, and USNM 161331.

Occurrence. Bird Spring Formation, 1-3 feet 

above base, USGS Iocs. 22465-PC (USNM 161536- 

161538), 23300-PC (USNM 161539-161548), Clark 

County; Tippipah Limestone, 1-3 feet above base, 

USGS loc. 22442-PC (USNM 161331), Nye County, 

Nev.

Genus DIABOLOCERAS Miller and Furnish, 1940 

Diaboloceras peroccidens n. sp.

Figures 9A-E, WA~F

Diagnosis. Diaboloceras with early whorls coiled 

as in Branneroceras, moderately involute for genus.

Eight-lobed suture without incipient lobes in umbilical region.

Description. Conch subdiscoidal, moderately 

large, the holotype still a phragmocone at diameter 

(estimated) of 75 mm, moderately evolute, width of 

umbilicus equal to two-fifths of conch diameter. 

Venter well-rounded, merging into flanks which are 

flat or very slightly convex and slope away from 

venter widening gradually toward umbilical shoulders, which are rounded. Umbilical wall strongly convex; umbilicus gently stepped within. Early whorls 

depressed (fig. 9A, B), planorbitally coiled as in 

Branneroceras, becoming gradually higher with 

growth; height and width reach equality in early 

part of ninth whorl; beyond this, its height exceeds 

width.

Slightly rursiradiate ribs ornament innermost 

flanks and umbilical shoulders, dying out about onethird of way across flanks and before middle of umbilical wall; riblets rather sharp on early whorls, 

becoming broader and gradually weaker on later 

whorls; on last four whorls of holotype, rib count is 

29-27-29-30, ending at outermost point of conch that 

has venter preserved. Transverse sinuous, minutely 

wavy lirae are bunched together over ribs so that 

four to six cover rib and one occupies interspace in 

adult; single or dichotomous lirae at each riblet in 

immature whorls; lirae spread out ventrad to form 

network where crossed by longitudinal lirae on ventral part of whorl. Transverse lirae begin parallel to 

ribs and form gentle sinus over inner flank, swing 

forward to form adoral bow over ventrolateral zone 

and a deeper rounded sinus over venter. Longitudinal lirae are strongest over venter and die out 

approximately at midflank, approximately 30 occurring on holotype between midflank and midventer; 

evenly spaced microscopic sculpture of transverse 

lirae on inner flank suggests continuation of longitudinal lineation; fairly sharp subtriagular nodes 

pointing orad occur at intersection of transverse and 

longitudinal lirae, particularly in ventral region.

Suture in adult shell includes in external part 

ventral and two pairs of lateral lobes, shown for 

holotype (fig. 10D) at diameter of 52 mm and 

slightly crushed paratype (fig. 10C) at diameter 

(estimated) of 65 mm. Ventral lobe wide, having 

two stout prongs with long points tilted slightly 

apart apicad, divided to a depth equal to about fourfifths of its overall length by median sinus shaped 

like inverted goblet. First lateral saddle about as 

wide as one prong of ventral lobe, very slightly 

asymmetric, broadly rounded orad. First lateral lobe 

slightly narrower than first lateral saddle, asymmetric, ventrad side gently convex throughout and dor-
EARLY PENNSYLVANIAN AMMONOIDS FROM SOUTHERN NEVADA C9

sad side convex becoming concave toward point. 

Second lateral saddle rather Jiarrowly rounded orad 

but spreading rather rapidly apicad. Second lateral 

lobe with point located just outside of umbilical 

shoulder, having ventral sid6 sigmoidal and dorsad 

side concave. Suture slopes diagonally across umbilical wall without forming incipient lobes.

Internal suture (fig. 10C) consists of narrow 

symmetrical hastate dorsal lobe separated by narrow 

saddles from pair of narrow, asymmetric first lateral 

lobes, slightly shorter than dorsal lobe. Shallow, 

slightly asymmetric saddles extend to edge of umbilical wall.

Suture in young phragmocone (fig. 10F) at approximate diameter (estimated) of 9 mm shows 

practically none of characteristic configuration of 

more mature sutures. Lobes are narrow and narrowly rounded apicad. However, immature suture in 

Branneroceras stage (fig. WE) at diameter of 

roughly 20 mm shows some^ semblance of asymmetric pointed lobes of adult.

USNM

161550 161551

specimen

161558 161553

Dimensions (mm)

Diameter 

Height of 

Width of 

Width of

(D) ____ ________

last whorl (H) ___ 

last whorl (W) ____

59.7 

23.2 

20.8 

24.0

29.7 

9.8 

11.3 

13.5

13.3 

3.0 

M.O

8.3

12.2 

3.5 

3.5

7.5

Proportions

U/D

W/D

W/H

0.40 

.35 

.90

0.45 

.38 

1.15

0.63 

.30 

1.33

0.61 

.41 

1.43

1 Twice the half width.

Discussion. Contributing to the description of 

this species are 19 specimens from six localities in 

Nye and Clark Counties, Nev. The suture of Diaboloceras peroccidens n. sp. lacks the incipient lobes 

on the umbilical wall that are found in the type species of the genus D. varicostatum Miller and Furnish. The nearest American species is D. neumeieri 

Quinn and Carr, which has a similar suture but 

broader whorls, a more evolute conch, and a strong 

tendency for the early whorls to be triangular in 

their coiling; this tendency is not found in D. peroccidens. Probably this western species is closest to D. 

ruzhencevi Andrianov from the Bashkirian Stage in 

the lower reaches of the Lena River in the Verkhoyansk region, U.S.S.R. The Siberian species is, 

however, more evolute than D. peroccidens; the 

width of the umbilicus in a specimen with a diameter of 50 mm is equal to slightly more than fiveeighths the diameter of the conch. The suture of D. 

ruzhencevi has a much narrower ventral lobe than 

D. peroccidens, each prong of which is considerably 

narrower than the first lateral lobe.

The evolutionary stage of development reached by 

Diaboloceras peroccidens n. sp. is intermediate between that of Branneroceras branneri (Smith) of 

early Bloyd (early late Morrow) age and Diaboloceras 

neumeieri Quinn and Carr of late Bloyd age. It 

already had gone beyond the Branneroceras stage of 

development and acquired a Diaboloceras suture by 

the migration of the umbilical lobe onto the inner 

flanks to become a second lateral lobe, but its early 

whorls resemble those of Branneroceras, not yet

FIGURE 9. Diaboloceras peroccidens n. sp. A-C, Side, back, and opposite side views X 1 of holotype, USNM 161550 from 

USGS loc. 23300-PC; D, side view X 1 of partly crushed paratype, USNM 161560 from USGS loc. 22442-PC; E, latex 

cast of external mold of early whorls X 3 of a paratype, USNM 161555 from USGS loc. 22465-PC.
CIO CONTRIBUTIONS TO PALEONTOLOGY

FIGURE 10. Cross sections and sutures of Diaboloceras peroccidens n. sp. A, B, Cross sections X l 1/^, 

X 5 of a paratype, USNM 161661 from USGS loc. 23300-PC; C, suture X 1% of a paratype, 

USNM 161552 from same locality as A, where H = 24 mm (approximately) ; D, external suture 

X 1% of holotype, USNM 161550, from same locality as A, where H = 18.7 and W = 17.2 mm; 

E, F, external sutures of two immature paratypes from USGS loc. 22465-PC, USNM 161557 

X 6, where H = 4.2 and W = 5.6 mm, and USNM 161556 X 8, where H = 2.4 and W = 3.6 mm.

having acquired the strong tendency toward triangular coiling shown by later species of Diaboloceras. This intermediate stage is presumably intermediate in time and can be assumed to have been 

reached toward the middle of Bloyd time.

TVpes. Holotype, USNM 161550; paratypes, 

USNM 161551-161562 inclusive.

Occurrence. Bird Spring Formation 1-3 feet 

above base, USGS Iocs. 22465-PC (USNM 161555- 

161559), 23300-PC (USNM 161550-161554), Clark 

County; Tippipah Limestone, lower part, USGS iocs. 

19668-PC (USNM 161561), 20559-PC (USNM 

161562), 22435-PC, and 22442-PC (USNM 161560), 

Nye County, Nev.

Genus STENOPRONORITES Schindewolf, 1934 

Stenopronorites sp.

Figures \\A-E, 12

This record is based upon three immature specimens, each from a different locality. Two of them 

are figured (fig. 11) and show the discoidal shape 

and planorbital coiling in the early stages of this 

species. In the largest specimen the whorl is beginning to increase in height, but the height is still less 

than the width. The venter and flanks are gently 

convex and the ventrolateral and dorsolateral zones 

strongly convex. Growth lines, preserved in two 

moderately large patches of surface sculpture, form 

a broad convex bow orad across each dorsolateral 

zone and flank and a shallower orad bow over the 

venter, the two bows separated by a rather narrow 

shallow sinus over each ventrolateral zone.

The suture (fig. 12) at a diameter of a little less 

than 12 mm is in the Pronorites stage. It consists 

of a trifid ventral lobe, a simple bifid first lateral 

lobe, two narrow slightly asymmetric lateral lobes 

and a rounded umbilical lobe, the last three lobes of

I

E

FIGURE 11. Stenopronorites sp. A-C, Back and side views 

X 1% and side view X 1 of specimen USNM 161548, from 

USGS loc. 23300-PC; D, E, back and side views X 2 of 

specimen USNM 161549, from USGS loc. 22465-PC.
EARLY PENNSYLVANIAN AMMONOIDS FROM SOUTHERN NEVADA cr.i

FIGURE 12. External suture of Stenopronorites sp. X 5 from specimen shown 

in figure 11A-C, where D = 11.7, 

H = 4.0, and W = 4.8 mm.

gradually diminishing lengths, 

dies are rounded.

The intervening sadUSNM specimen

161548 161549 161332

Dimensions (mm)

Height of last whorl (H)

Width of umbilicus (U)

_ 12.0 

3.8

5.0

- 6.7

9.0 5.3 

2.9 1.6 

3.3 2.0 

5.0 3.1

Proportions

U/D .

W/D __ _

W/H . _ __ _ __ _ _ _. __ __ . ._ _.

0.56 

.42

. 1.31

0.56 0.58 

.37 .38 

1.17 1.25

Discussion. The first of these specimens to be 

found was the smallest and came from the C. P. 

Hills. A little over 5 mm in diameter, it consists of 

only three whorls, the suture limited to the first two. 

It was tentatively identified as Boesitesl in Poole, 

Orkild, Gordon, and Duncan (1965, p. A52). The 

later finding of two specimens from Clark County 

permitted the recognition of this species as a pronoritid.

Although no specimens from the Diaboloceras 

peroccidens Zone show the adult characters of Stenopronorites, the fact that these immature shells are 

already in the Pronorites stage of development and 

that adult Pronorites has not been found above the 

Mississippian renders the reference to Stenopronorites reasonably certain.

Figured and measured specimens. USNM 

161332, 161548, and 161549.

Occurrence. Tippipah Limestone, lower 20 feet, 

USGS loc. 22071-PC (USNM 161332), Nye County;

Bird Spring Formation, 1-3 feet above base, USGS 

loc. 22465-PC (USNM 161549), 23300-PC (USNM 

161548), Clark County, Nev.

REFERENCES CITED

Gordon, Mackenzie, Jr., 1964, Carboniferous cephalopods of 

Arkansas: U.S. Geol. Survey Prof. Paper 460, 314 p., 32 

pis., 96 figs. [1965].

Gordon, Mackenzie, Jr., and Poole, F. G., 1966, MississippianPennsylvanian boundary in southwestern Nevada and 

southeastern California [abs.]: Geol. Soc. America, Rocky 

Mountain Sec., Ann. Mtg., 19th, Las Vegas, Nev., 1966, 

Program, p. 30-31.

 1968, Mississippian-Pennsylvanian boundary in southwestern Nevada and southeastern California, in Eckel, 

E. B., ed., Nevada Test Site: Geol. Soc. America Me-n. 

110 (in press).

Librovitch, L. S., 1938, KamennougoPnye ammonei s yuzhnoro 

ostrova Novoi Zemli [Carboniferous ammonoids of the 

southern island of Novaya Zemlya]: Vses. Arkticheskii 

Inst., Leningrad, Trudy, v. 101, p. 47-107, 5 pis., 13 

figs. (English summ., p. 85-104).

Longwell, C. R., and Dunbar, C. 0., 1936, Problems of Perrnsylvanian-Permian boundary in southern Nevada: Am. 

Assoc. Petroleum Geologists Bull., v. 20, p. 1198-1207, 

6 figs.

Miller, A. K., and Furnish, W. M., 1940, Studies of Carboniferous ammonoids; Pts. 5-7: Jour. Paleontology, v. 14, 

no. 6, p. 521-543, pis. 62-65, 7 figs.

Miller, A. K., and Moore, C. A., 1938, Cephalopods from the 

Carboniferous Morrow group of northern Arkansas and 

Oklahoma: Jour. Paleontology, v. 12, no. 4, 341-3F4, 

pis. 43, 44, 4 text figs.

Miller, A. K., and Owen, J. B., 1937, A new Pennsylvanian 

cephalopod fauna from Oklahoma: Jour. Paleontology, 

v. 11, no. 5, p. 403-422, pis. 50-52, 5 figs. 

Poole, F. G., Orkild, P. P., Gordon, Mackenzie, Jr., and Duncan, Helen, 1965, Age of the Eleana Formation (Devonian and Mississippian) in the Nevada Test Site, in Cohee, 

G. V., and West, W. S., Changes in stratigraphic nomenclature by the U.S. Geological Survey, 1964: U.S. Geol. 

Survey Bull. 1224-A, p. A51-A53.

Schindewolf, 0. H., 1934, Uber zwei jungpalaozoische Cephalopodenfaunen von Menorca: Gesell. Wiss. Gottingen, 

math.-phys. Kl., Abh., Folgo 3, Heft 10, p. 159-192, pi. 

6, 4 figs.

Webster, G. D., and Lane, N. G., 1967, Mississippian-Petmsylvanian boundary in southern Nevada, in Essays in 

paleontology and stratigraphy R. C. Moore Commemorative Volume: Kansas Univ., Dept. of Geology Spec. 

Pub. 2, p. 503-522, 4 figs.

INDEX

[Italic page numbers indicate major references and descriptions]

Acknowledgments ___ 

Ammonoid localities 

Axinolobus modulus

Bird Spring Formation __1, 4, 5, 6, 8, 10, 11 

Bisatoceras ___________________ 1, 6

nevadtnse __________________6, 7, 8

paynei ________________ 8

primiim _________-_____ __ 8

(Pseudobisatoceras) secundum __ 8 

Bloyd Shale, Brentwood Limestone

Member ________ 4

Trace Creek Shale Member ___-_ 4 

Boesites _____________________ 1, 11

branneri, Brannerocera* __________ 4, 9

Brannerocerax ___________.;__1, 8, 9

branneri _________________ 4, 9

C. P. Hills ________________1, 3, 8, 11 

Chainman Shale ________________ 3

Cravenoceras _______________ 6, 8

merriami ______________ 3

morrowense ____________ 5, 6

depressum, Syngastrioceras ______ 5

Diaboloceras _______________1, 4, 8, 9, 10 

neumeieri _______________ 4, 9

peroccidens _________3, 4, 8, 9, 10, 11

peroccidens Zone _________ 4

ruzhencevi _______________ 9

varicostatum ____________ 9

Eleana Formation _____________ 1, 3

Gastrioceras globulonum _.

Glaphyriten _______.

morroivensis _____-

oblatus ________

globosum, Syngastrioceras

globulosum, Gastrioceras .

Goniatiteg nolinensis ___-

Page 

05 

6 

6 

6 

5 

5

Hale Formation 5

Indian Springs __-__- - 1, 5, 8 

Indian Springs Member _ 4 

Indian Springs region 3 

Introduction ___________ ____ 1

Janei, Syngastrioceras _ _______ 4, 5

Las Vegas lateral shear zone 3, 4

Lucky Strike Wash ____________ 1, 4

McCaleb, 3. A., written communication 6

Mercury, Nev ___________ _ 1

merriami, Cravenoceras ___________ 3

modulus, A-xinolobux ___-__ __ _ 4

Monte Cristo Limestone - 3 

morroivenne, Cravenoceras ______ 5, 6

morrowensift, Glaphyrltes _______ 6

neumeieri, Diaboloceras _-____ 4, 9 

Nevada Test Site ______________1, 3, 8 

nevadense, Bisa-toceras _________6, 7, 8

nevademis, Rhipidomella ________ 4

nolinenais, Goniatttes _________ _ 6

oblatum, Syngastrioceras _____1, 4, 5, 6 

oblatux, Glaphyrites __________ 5, 6

P'.ee 

paynet, Bisatoceras ______ _ __ C8

peroccidens, Diaboloceras 3, 4, 8, 9, 10, 11 

primwn, Bisatoceras 8 

Pronorites __________ _ -_ 10, 11

( Pseudobisatoceras) secundum,

Bisatoceras -______ _ 8

Pygmaeoceras solidum 6

Red Canyon section 1, 3

Rhipidomella nevadensis 4

ritzhencevi, Diaboloceras __ 9

necundum, Bisatoceras

(Pseudobisatoceras) 8 

solidum, Pygmaeoceras __ _ 6 

Spring Mountains - __ _ 1, 3 

Stenopronorites 1, 10, 11 

Stratigraphic setting 3 

Sungastrioceras 4, 6 

depressum _______ ___ 5

globosum _______ 5

lanei ____ 4, 5 

oblatum _________ 1, 4, 5, 6

Tippipah Limestone ____ 3, 4, 5, 8, 10 11 

Tippipah Spring quadrangle _ 1 

Trace Creek Shale Member _ 4

iiaricostati</m, Diaboloceras __ 

Verkhoyansk region, U.S.S.R.

Yucca Lake quadrangle _ _

C13

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