The Upper Cretaceous Dimorphic Pachydiscid 

Ammonite Menuites in the Western Interior 

of the United States 

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The Upper Cretaceous Dimorphic Pachydiscid 

Ammonite Menuites in the Western Interior 

of the United States 

By William A. Cobban andW. James Kennedy 

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 

Descriptions and illustrations of 

two important species ofMenuites 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1993 
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

For sale by 

USGS Map Distribution 

Box 25286, Building 810 

Denver Federal Center 

Denver, CO 80225 

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does 

not imply endorsement by the U.S. Government. 

Library of Congress Cataloging-in-Publication Data 

Cobban, William Aubrey, 1916-

The Upper Cretaceous dimorphic pachydiscid ammonite Menuites in the western interior of the 

United States I by William A. Cobban and W. James Kennedy. 

p. cm.-(U.S. Geological Survey professional paper; 1533) 

Includes bibliographical references. 

1. Menuites portlocld complexus-West (U.S.) 2. Menuites oralensis-West (U.S.) 3. PaleontologyCretaceous. 4. Paleontology-West (U.S.) I. Kennedy, W. J. (William James) II. Title. III. Series. 

QE807.A5C6374 1994 

564' .53-dc20 92-37418 

CIP 
CONTENTS 

Abstract ............................................................................................................................. 1 

Introduction....................................................................................................................... 1 

Acknowledgments ............................................................................................................ 2 

Localities of Menuites ....................................................................................................... 2 

Systematic Descriptions.................................................................................................... 2 

Menuites portlocki (Sharpe,1855) complexus (Hall and Meek, 1856) ................... 2 

Menuites oralensis n. sp. ........................................................................................ 9 

References Cited ............................................................................................................... 12 

PLATES 

[Plates follow references] 

1-3. Menuites portlocki complexus. 

4-8. Menuites oralensis n. sp. and M. portlocki complexus. 

9-14. Menuites oralensis n. sp. 

FIGURES 

1. Map of part of the Western Interior showing localities of Menuites .......................................................................... 3 

2. External suture of Menuites portlocki complexus (Hall and Meek) ........................................................................... 8 

3. Histogram showing base diameters of body chambers of Menuites oralensis n. sp. microconchs ............................ 10 

4. Scatter diagram showing umbilical diameter to shell diameter ratios of Menuites oralensis n. sp. microconchs ..... 11 

5. Scatter diagram showing whorl breadth-to-height ratios of Menuites oralensis n. sp ............................................... 11 

6. External suture of Menuites oralensis n. sp ................................................................................................................ 12 

TABLES 

1. Localities where Menuites were collected .................................................................................................................. 4 

2. Dimensions and features of Menuites portlocki complexus from near Fort Thompson, S. Dak ................................ 5 

3. Dimensions and features of Menuites portlocki complexus from near Rock River, Wyo.......................................... 7 

III 

THE UPPER CRETACEOUS DIMORPHIC PACHYDISCID 

AMMONITE MENUITES IN THE WESTERN INTERIOR 

OF THE UNITED STATES 

By William A. Cobban1 and W. James Kennedy2 

ABSTRACT 

Highly dimorphic pachydiscid ammonites are fairly 

abundant in Montana, South Dakota, Wyoming, and Colorado, and a few specimens are known from Utah and New 

Mexico. Two chronologie species are recognized, each 

represented by small adults (microconchs) and large adults 

(macroconchs). Microconchs have been assigned to Menuites Spath, 1922, whereas macroconchs have usually been 

assigned to Anapachydiscus Yabe and Shimizu, 1926. 

Both forms are considered Menuites in the present report. 

Menuites portlocki complexus (Hall and Meek, 1856), the 

older of the two species, occurs in the zones of Baculites 

gregoryensis and B. reduncus. The younger species, from 

the zone of B. scotti, is designated as Menuites oralensis 

n. sp. 

INTRODUCTION 

Hall and Meek (1856, p. 394, pl. 4, figs. 1a-t) 

described the new species Ammonites complexus based on 

two small pyritized ammonites from the "Great Bend on 

the Missouri. Lower part of division No. 4." The specimens, both juvenile whorls, came from rocks now 

assigned to the Gregory Member of the Pierre Shale in 

south-central South Dakota. Most of the member lies in 

the ammonite zone of Baculites gregoryensis, which is in 

the upper part of the middle Campanian in the Western 

Interior sense and in the middle part of the upper Campanian in the European sense. Subsequent collecting from 

the Gregory Member has shown that Hall and Meek's 

(1856) specimens are examples of the innermost whorls of 

a dimorphic pachydiscid ammonite that occurs as a moderately sized form (microconch) having ventrolateral 

1

U.S. Geological Survey, Box 25046, Federal Center, Denver, CO 

80225. 

2aeological Collections, University Museum, Parks Road, University 

of Oxford, Oxford OXI 3PW, U.K. 

tubercles on the adult body chamber and as a much larger 

form (macroconch) lacking ventrolateral tubercles. Both 

forms occur together, and they cannot be differentiated by 

their innermost whorls alone. Adults of the microconch 

have all the characteristics of the genus Menuites Spath 

(1922, p. 123, type species by original designation Ammonites Menu Forbes, 1846, p. 111, pl. 10, fig. 1). Some 

specimens from the Western Interior have been assigned 

to Menuites? n. sp. (for example, Gill and Cobban, 1966, 

p. A56). The macroconch form has all of the characteristics of the genus Anapachydiscus Yabe and Shimizu 

(1926). The type species of Anapachydiscus is, by original 

designation, Pachydiscus (Parapachydiscus) fascicostatus 

Yabe (Yabe and Shimizu, 1921, p. 57, pl. 8, fig. 5; pl. 9, 

figs. 2-5). Hall and Meek's (1856) Ammonites complexus 

has been assigned to Pachydiscus (Grabau and Shimer, 

1910), Parapachydiscus (Dane and others, 1937), and 

Anapachydiscus with a query (for example, Scott, 1963, 

1969; Scott and Cobban, 1965) or without a query (for 

example, Schultz, 1965; Izett and others, 1971). 

The same co-occurrence of small, tuberculate Menuites (described as M. sanadai Matsumoto, 1984, p. 17, pl. 5, 

fig. 1; text fig. 5) with the much larger type species of 

Anapachydiscus was described by Matsumoto (1984, p. 

18), who noted that "M. sanadai and A.fascicostatus could 

be interpreted as constituting a dimorphic pair." It seems 

likely that the small tuberculate Pachydiscidae are all 

microconchs of larger nontuberculate forms, but not all 

dimorphic pairs can be linked together at this time 

(Kennedy and Summesberger, 1984, p. 158; and Kennedy, 

1986, p. 30; provide additional discussion). The type 

species of Menuites, for example, is yet to be linked to a 

macroconch. In spite of this, the case for dimorphism 

between Menuites and Anapachydiscus is strong, and we 

regard the former as having priority over the latter, 

although it will continue to be necessary to use Anapachydiscus for those species of which a Menuites microconch 

has not yet been recognized (even though the nomenclature 

is unsatisfactory). 
2 UPPER CRETACEOUS DIMORPHIC PACHYDISCID AMMONITE MENUITES IN THE WESTERN INTERIOR 

ACKNOWLEDGMENTS 

Neal L. Larson of the Black Hills Institute of Geological Research in Hill City, S. Dak., kindly loaned us the 

best of the institute's Menuites from the Pierre Shale of 

south-central and southwestern South Dakota. Steven Jorgensen of Fargo, N. Dak., allowed us to study his large 

and superb collection of Menuites from the Oral area in 

Fall River County, S. Dak. Donald W. Boyd of the University of Wyoming, Laramie, made available for study a 

large collection of Menuites from the Rock River area in 

Albany County, Wyo. Harold Mendryk (New York, N.Y.), 

Gale A. Bishop (Georgia Southern College, Statesboro), 

and the late Edward Shibata (Laramie, Wyo.) generously 

donated many excellent specimens from the Pierre Shale 

of South Dakota and Wyoming and from the Rock River 

Formation of Wyoming. Kennedy acknowledges the financial support of the Natural Environment Research Council 

(United Kingdom) and the technical assistance of the staff 

of the Geological Collections at Oxford University 

Museum and the Department of Earth Sciences of Oxford 

University. 

LOCALITIES OF MENUITES 

Localities where Menuites were collected in the 

Western Interior are shown in figure 1. The locality numbers, names of collectors, years of collection, geographic 

descriptions, and stratigraphic assignments of U.S. Geological Survey (USGS) Mesozoic localities are given in 

table 1. 

SYSTEMATIC DESCRIPTIONS 

The following prefixes are used to indicate the repositories of the specimens mentioned in the text: 

USNM (National Museum of Natural History, 

Washington, D.C.) 

AMNH (American Museum of Natural History, 

New York, N.Y.) 

IGS (Institute of Geological Sciences, 

Keyworth, Nottinghamshire, England) 

BHI (Black Hills Institute of Geological 

Research, Hill City, S.Dak.) 

All dimensions are in millimeters. Umbilical diameter, whorl breadth, and whorl height are also given as 

ratios to the shell diameter (in parentheses immediately 

following the dimension). Rib and tubercle counts are 

given for one-half whorl in order to utilize specimens of 

less than a full whorl. 

Family PACHYDISCIDAE Spath, 1922 

Genus MENUITES Spath, 1922 

(also Besairieites Collignon, 1931; and Anapachydiscus Yabe and 

Shimizu, 1926) 

Type species.-By original designation, Ammonites Menu Forbes 

(1846, p. 111, pl. 10, fig. 1). 

Menuites portlocki (Sharpe, 1855) complexus (Hall and Meek, 1856) 

Plates 1-3; plate 4, figures 4-10; plate 5, figures 1, 5-7; plate 6, figures 

9-15; plate 7, figure 5; plate 8, figures 3, 4; text figure 2 

1856 Ammonites complexus Hall and Meek, p. 394, pl. 4, figs. la-f. 

1861 Ammonites complexis [sic] Hall and Meek. Gabb, p. 65 (part). 

1864 Ammonites complexus Hall and Meek. Meek, p. 24. 

1876 Ammonites complexus Hall and Meek. Meek, p. 447, pl. 24, 

figs. la-c. 

1893 Ammonites complexus Hall and Meek. Boyle, p. 29. 

?1907 Pachydiscus complexus (Hall and Meek)? Weller, p. 819, pl. 

101, figs. 3, 4. 

1910 Pachydiscus complexus (Hall and Meek). Grabau and Shimer, 

p. 174. 

1916 Pachydiscus complexus (Hall and Meek). Gardner, p. 378. 

1925 Ammonites complexus Hall and Meek. Diener, p. 25. 

1937 Parapachydiscus complexus (Hall and Meek). Dane, Pierce, 

and Reeside, p. 230. 

1952 Pachydiscus complexus (Hall and Meek). Cobban and 

Reeside, p. 1020. 

1959 Anapachydiscus [complexus Hall and Meek]. Scott and 

Cobban, p. 126. 

?1962 Menuites aff. M. complexus (Hall and Meek). Reeside, p. 122, 

pl. 69, figs. 1-6. 

1963 Anapachydiscus? complexus (Hall and Meek). Scott, p. 101 

(part). 

1963 Menuites? n. sp. Scott, p. 101 (part). 

1965 Anapachydiscus complexus (Hall and Meek). Schultz, p. B12. 

1970 Anapachydiscus n. sp. Gill, Merewether, and Cobban, p. 23. 

1970 Menuites n. sp. Gill, Merewether, and Cobban, p. 23. 

1975 Anapachydiscus complexus (Hall and Meek). Scott and 

Cobban, listed on map. 

1975 Menuites n. sp. Scott and Cobban, listed on map. 

1976 Anapachydiscus complexus (Hall and Meek). Kennedy and 

Cobban, pl. 7. fig. 3. 

Types.-Hall and Meek (1856, p. 349) based their 

new species on two small septate coils of which the larger 

one, AMNH 9531/1 (Hall and Meek, 1856, pl. 4, figs. 1 b, 

c, e, f), is herein designated the lectotype. As they 

described it, both specimens are from the "Great Bend on 

the Missouri" in south-central South Dakota. They are 

probably from Lyman County, where the Campanian Baculites gregoryensis zone of the Gregory Member of the 

Pierre Shale contains numerous small marcasitic coils of 

Menuites like those of Hall and Meek. 

Diagnosis.-Dimorphic pachydiscid ammonites characterized by strong, widely spaced ribs on robust inner 

whorls. Ribs mostly disappear on body chambers of 

microconchs but reappear strongly at the aperture. Umbilical tubercles are present on the phragmocone and body 

chambers of microconchs, as are large, usually nodal, 
SYSTEMATIC DESCRIPTIONS 

~ 

---- CANADA ------- . --------UNITED STATEST ______ _ 

Rwer 

1 

~----

{ 4., ·I __ '> 

. 

I YELLOWSTONE 

NATIONAL 

0 I PARK 

:I: I 

9J 

I 

I 

I 

UTAH 

ARIZONA 

Lander 

Rawlins 0 

0 Montrose 

Farmington 

MONTANA 

Canon City 

El Vado 

0 

X 

100 

I 

I 

NORTH DAKOTA 

SOUTH DAKOTA 

4-8 

Red Bird 2,l ~+I ____________ Oral 

_ 

I 

I 

I P;Ofte 

I 

I 

oCHEYENNE 

I 

I 

\ 

I 

NEBRASKA 

r--------

\ 

I 

I 

\ KANSAS 

I 

I 

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--------- ___ l __________ _ 0 

Raton T OKLAHOMA 

~----------

NEW MEXICO 1 TEXAS 

100 200 MILES 

200 300 KILOMETERS 

Figure 1. Index map of part of the Western Interior of the United States showing localities of Menuites portlocki complexus (Hall and Meek, 1856) (indicated by pluses) and M. oralensis n. sp. (indicated by crosses). 

Numbers refer to USGS Mesozoic localities listed in table 1. Unnumbered symbols are localities from private 

collections. 

3 
4 UPPER CRETACEOUS DIMORPHIC PACHYDISCID AMMONITE MENU/TES IN THE WESTERN INTERIOR 

Table 1. Localities where Menuites were collected. 

[Prefix D indicates Denver Mesozoic locality numbers; all others are Washington, 

D.C., Mesozoic locality numbers] 

Locality 

(fig. 1) 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

USGS Mesozoic Collector, year of collection, description of locality, 

locality and stratigraphic assignment 

013160 Harold Mendryk, 1972. Bluff along Cheyenne 

River in the SWl/4 sec. 21, T. 40 N., R. 61 

W., Niobrara County, Wyo. Pierre Shale, 

from limestone concretions in the Red Bird 

Silty Member. 

01922 H.A. Tourtelotandothers, 1958. NearRedBird 

in the NEI/4 sec. 23, T. 38 N ., R. 62 W., Niobrara County, Wyo. Pierre Shale, from silty, 

calcareous concretions 12m below the top of 

the Red Bird Silty Member. 

01923 H.A. Tourtelotandothers, 1958. NearRedBird 

in the NW1/4 sec. 13, T. 38 N., R. 62 W., 

Niobrara County, Wyo. Pierre Shale, same 

stratigraphic position as 01922 (Joe. 2). 

0901 W.A. Cobban, 1956. South side of Beaver 

Creek, near Cheyenne River in the SW1/4 

NEl/4 and SE1/4NW1/4 sec. 22, T. 7 S., R. 7 

E., Fall River County, S. Oak. Pierre Shale, 

from gray limestone concretions in the Red 

Bird Silty Member. 

0903 W.A. Cobban, 1956. North side of Cheyenne 

River in the NWl/4NWl/4 sec. 23, T. 7 S., 

R. 7 E., Fall River County, S. Oak. Pierre 

Shale, from gray limestone concretions in 

the Red Bird Silty Member. 

01411 G.R. Scott and W.A. Cobban, 1957. Cheyenne 

River bluff 1.75 km northeast of Oral in the 

NW1/4NW1/4 sec. 26, T. 7 S., R. 7 E., Fall 

River County, S. Oak. Pierre Shale, from 

gray limestone concretions in the Red Bird 

Silty Member. 

10385 T.W. Stanton, 1920. Mouth of Beaver Creek 

on Cheyenne River, Fall River County, S. 

Dak. Pierre Shale. 

013159 G.A. Bishop, 1968. NEI/4 sec. 22, T. 7 S., R. 7 

E., Fall River County, S. Oak. Pierre Shale. 

12844 T.W. Stanton, 1924. "2lh to 4 miles east of 

Rock River, Wyo." [Rock River Formation]. 

12848 J.B. Reeside, Jr., and T.W. Stanton, 1924. 

About 8 km east of Rock River, Albany 

County, Wyo. "Mesaverde Formation" 

[Rock River Formation]. 

22935 J.B. Reeside, Jr., H.R. Christner, and W.A. 

Cobban, 1950. About 5.6 km east of Rock 

River, Albany County, Wyo. Rock River 

Formation. 

0357 G. R. Scott and W.A. Cobban, 1955. NW1/4 

sec. 9, T. 20 N., R. 76 W., Albany County, 

Wyo. Rock River Formation. 

01392 G.R. Scott and W.A. Cobban, 1957. NEI/4 sec. 

9, T. 20 N., R. 76 W., Albany County, Wyo. 

Rock River Formation, from sandstone concretions 187-196 m above base of formation. 

Table 1. Localities where Menuites were collected.-Continued 

Locality 

(fig. 1) 

14 

15 

16 

17 

18 

19 

20 

USGS Mesozoic Collector, year of collection, description of locality, 

locality and stratigraphic assignment 

01400 

013161 

1725 

01082 

03394 

0297 

0715 

G.R. Scott and W.A. Cobban, 1957. West 

slope ofhill3.2 km southeast of Rock River 

in the SE1/4NE1/4 and NEl/4SEI/4 sec. 8, T. 

20 N., R. 76 W., Albany County, Wyo. 

Rock River Formation, from silty calcareous concretions 157-165 m above base of 

formation. 

Edward Shibata, 1968. Southeast of Rock 

River in the ElhE1/2 sec. 8 and N1h sec. 9, 

T. 20 N., R. 76 W., Albany County, Wyo. 

Rock River Formation. 

T.W. Stanton, 1896. "Two to three miles northwest of Harper, Albany County, Wyo." 

(probably from the Rock River Formation in 

the Slh sec. 32, T. 21 N., R. 75 W., Albany 

County, Wyo.]. 

J.F. Clement and H.B. Fields, 1956. East of 

Rock River near the center of the south line 

ofT. 21 N., R. 75 W., Albany County, Wyo. 

"Mesaverde Formation [Rock River Formation] 290-329 m below base of Pine Ridge 

Sandstone." 

A.D. Zapp, 1961. SE1/4NE1/4 sec. 33, T. 21 

N., R. 75 W., Albany County, Wyo. "About 

435 feet above base of Mesaverde Formation" [Rock River Formation]. 

G.R. Scott, 1955. North of Kassler in the 

SW1/4SE1/4 sec. 15, T. 6 S., R. 69 W., Jefferson County, Colo. Pierre Shale, from 

Hygiene Sandstone Member. 

G.R. Scott and W.A. Cobban, 1955. Arroyo in 

the SE1/4SE1/4 sec. 15, NEI/4NEl/4 sec. 22, 

and NWI/4 sec. 23, T. 20 S., R. 64 W., 

Pueblo County, Colo. Pierre Shale, from 

ironstone concretions in the upper part of 

Rusty zone of Gilbert (1897), about 255 m 

above base of Pierre Shale. 

moderately closely spaced ventrolateral tubercles on the 

adult body chambers. Inner whorls of macroconchs are 

like those of microconchs, but adults lack ventrolateral 

tubercles and terminal ribs. Adult macroconchs have 

inflated whorls with well-rounded flanks. 

Description.-The lectotype (Hall and Meek, 1856, 

pl. 4, figs. 1 b, c, e, t) consists of parts of two whorls. The 

outer, larger part represents one-third of a stout whorl 36 

mm in length that has a breadth of 26.5 mm. Its cross 

section has a steep umbilical wall, a narrowly rounded 

umbilical shoulder, a very broadly rounded flank, and a 

well-rounded venter. Ornament consists of strong, flattopped umbilical bullae that probably numbered 4 per onehalf whorl, and narrow, rectiradiate ribs that numbered 12 

or 13 per one-half whorl. Ribs arise either from the 
SYSTEMATIC DESCRIPTIONS 5 

umbilical bullae or from low on the flank between them. 

Suture is highly denticulate (Hall and Meek, 1856, pl. 4, 

figs. 1e, 0. The paralectotype is a juvenile that includes 

half a whorl of body chamber. The specimen has a diameter of 17.0 mm and a breadth of 12.3 mm. 

A large collection of 227 specimens, all juveniles or 

parts of or complete inner whorls preserved like those of 

Hall and Meek, were made available for study by the Black 

Hills Institute of Geological Research. The specimens were 

collected by Ed Cole of Delta, Utah, from the Baculites 

gregoryensis zone of the Gregory Member of the Pierre 

Shale at Fort Thompson just below the "Great Bend of the 

Missouri River" (fig. 1). Whorls less than 3.7 mm in diameter are broader than they are high and lack ornament. 

Weak constrictions that begin at the umbilical shoulder and 

cross the flank and venter with a slight forward arching 

arise at a diameter of 3.7-4.3 mm and number about three 

per whorl. They are usually bounded by weak ribs of which 

the adapical one may be the highest. These constrictions 

disappear at a diameter of 5.3-6.7 mm. Whorls then remain 

smooth until reaching a diameter of 7.5-10.3 mm, when 

tubercles arise on the umbilical shoulder. The umbilical 

tubercles, which number four to six per one-half whorl, are 

bullate at first, but at a diameter of 14 mm they may 

become flat -topped where they probably formed the bases 

of hollow spines. Rectiradiate to slightly prorsiradiate, 

straight, narrow ribs arise from the umbilical tubercles or 

intercalate between them at a diameter of 10-20 mm. The 

ribs are widely spaced (8-16 per one-half whorl), are much 

narrower than the interspaces, and cross the venter with a 

slight forward bending. The largest specimen in the BHI 

collection is part of a microconch that may have had a 

diameter of about 65 mm. At this size, ribbing declines and 

conspicuous, large, nodal ventrolateral tubercles arise. 

Dimensions, ratios, and node and rib counts of 18 wellpreserved small specimens from the Gregory Member of 

the Pierre Shale are shown in table 2. 

A few large, incomplete macroconchs have been 

found in the Chamberlain-Fort Thompson area in southcentral South Dakota. Two phragmocones from this region 

in the collections of the Black Hills Institute of Geological 

Research merit description. Both have the venter and one 

Table 2. Dimensions and features of Menuites portlocki complexus from the Baculites gregoryensis zone of the Pierre Shale near Fort 

Thompson, S. Dak. 

[Abbreviations of features: D, shell diameter; U, umbilical diameter; Wb, whorl breadth; Wh, whorl height. Quantities in parentheses are ratios of measurements to 

shell diameter; leaders( .... ), no measurement] 

Umbilical nodes Ribs per 

Specimen D u Wb Wh Wb:Wh per half whorl half whorl 

USNM 456636 21.8 5.0 (0.23) 15.0 (0.69) 11.4 (0.52) 1.32 6 13 

456637 22.7 5.2 (0.23) 15.7 (0.69) 11.0 (0.48) 1.43 6 14 

456638 29.9 6.2 (0.21) 18.3 (0.61) 16.5 (0.55) 1.11 6 14 

456639 34.4 7.2 (0.21) 22.5 (0.65) 16.7 (0.49) 1.35 6 12 

456640 25.5 5.3 (0.21) 18.2 (0.71) 12.6 (0.49) 1.44 6 13 

456641 27.5 6.9 (0.25) 21.3 (0.77) 13.4 (0.49) 1.59 6 13 

456642 31.1 7.1 (0.23) 19.3 (0.62) 15.2 (0.49) 1.27 8 16 

456643 33.4 6.3 (0.19) 21.6 (0.65) 16.5 (0.49) 1.31 7 16 

456644 31.6 7.7 (0.24) 21.8 (0.69) 6 15 

456645 33.3 6.8 (0.20) 21.4 (0.64) 16.6 (0.50) 1.29 7 14 

456646 32.3 5.6 (0.17) 21.3 (0.66) 16.6 (0.51) 1.28 7 15 

456647 32.5 8.3 (0.26) 20.5 (0.63) 15.9 (0.49) 1.29 6 11 

Bill 2070 32.4 5.7 (0.18) 21.0 (0.65) 14.9 (0.46) 1.41 5 12 

2071 33.1 7.1 (0.21) 22.4 (0.68) 16.5 (0.50) 1.36 4 8 

2072 24.7 5.8 (0.23) 18.1 (0.73) 11.9 (0.48) 1.52 5 10 

2073 28.0 6.4 (0.23) 18.2 (0.65) 14.4 (0.51) 1.26 6 14 

2074 21.3 5.4 (0.25) 14.7 (0.69) 10.2 (0.48) 5 

2075 36.0 8.7 (0.24) 23.2 (0.64) 18.2 (0.51) 1.27 6 10 
6 UPPER CRETACEOUS DIMORPHIC PACHYDISCID AMMONITE MENUITES IN THE WESTERN INTERIOR 

flank very well preserved, but the other flank is incomplete or somewhat crushed. BHI 2113 has a diameter of 

193 mm, an umbilicus of 46.5 mm (0.24), a whorl breadth 

of about 122 mm (0.63), a whorl height of 85 mm (0.44), 

and a whorl breadth-to-height ratio (Wb:Wh) of 1.44. 

Umbilical bullae are present on all visible whorls, with 11 

on the outer whorl. Other ornament is lacking on the wellrounded flanks and venter. BHI 2114 has a diameter of 

183 mm, an umbilicus of 42.5 mm (0.23), whorl breadth 

of about 98 mm (0.54}, a whorl height of 80 mm (0.44), 

and a Wb:Wh of 1.23. Flanks and venter are well rounded, 

and ornament consists only of 12 lengthy umbilical bullae 

on the outer whorl. 

Although the Gregory Member of the Pierre Shale in 

south-central South Dakota contains numerous juveniles 

and inner whorls of M. portlocki complexus but no complete adults, the Rock River Formation in southeastern 

Wyoming contains good examples of adult specimens. 

The best collections come from outcrops a few kilometers 

southeast of Rock River (fig. 1, locs. 9-18). 

Eleven microconchs are present in the collections 

from the Rock River area. Their phragmocones are coarsely 

ribbed like those on comparable-sized whorls from the Gregory Member of the Pierre Shale of South Dakota. Umbilical tubercles on the Rock River phragmocones are bullate 

and number five or six per one-half whorl. Strong, rectiradiate to slightly prorsiradiate ribs, 8-11 per one-half whorl, 

arise in pairs from the umbilical bullae or singly from low 

on the flank between them. Body chambers of the microconchs begin at diameters from 37.6 to 62.0 mm with most 

in the 52- to 55-mm range. Ribs weaken greatly near the 

end of the phragmocone, and most disappear on the older 

part of the body chamber. Umbilical bullae weaken but 

persist onto the body chamber, where they migrate out to 

the lower part of the flank. Ventrolateral tubercles arise 

rather abruptly at a diameter of 51-69 mm either near the 

end of the phragmocone or on the basal part of the body 

chamber. The first pair of tubercles is usually low and bullate, but the rest are large and nodal. Most specimens have 

only four pairs of tubercles, which are either matched (pl. 

1, fig. 8) or alternate (pl. 6, fig. 14) or both. Weak looped 

ribs may connect the ventrolateral and umbilical tubercles 

(pl. 1, fig. 10). On some specimens, the broad space on the 

flank and venter that separates the sets of tubercles is either 

devoid of ribs (pl. 1, figs. 9, 10) or has a few barely detectable ribs. Ribbing rejuvenates near the aperture, where two 

or three narrow ribs arise from umbilical bullae, cross the 

flank rectiradially, and then bend forward slightly and cross 

the venter in a broad convexity (pl. 7, fig. 5). One or two 

weak secondary ribs may separate the primary ribs. Dimensions, ratios, and numbers of ribs and umbilical tubercles 

for 19 microconchs and macroconchs from Rock River are 

given in table 3. 

Macroconchs are much more numerous than microconchs in the collections from the Rock River area. About 

35 of the macroconchs are suitable for measurements. 

Innermost whorls are robust and are broader than they are 

high; the greatest breadth is at the umbilical shoulder. The 

umbilicus is moderately deep and has a narrowly rounded 

wall and shoulder. Flanks and venter are broadly rounded. 

Ribbing on the innermost whorls is coarse like that of 

comparable-sized microconchs, and most specimens have 

10-12 ribs per one-half whorl. Umbilical bullae, which 

number five or six per one-half whorl, are usually flattopped (pl. 6, fig. 10) and are probably the bases of hollow spines. Some individuals have both flat-topped and 

sharp umbilical bullae (pl. 6, fig. 13). On larger whorls, 

ribbing weakens and disappears at a diameter of 80-100 

mm (pl. 2, figs. 4, 5; pl. 3; pl. 5, figs. 5-7). Umbilical 

bullae gradually weaken as the shell enlarges, and they 

usually disappear at a diameter of 100-150 mm. They are 

rejuvenated, however, on the largest shells. The largest 

specimen, USNM 456667 (fig. 1, loc. 9), is 360 mm in 

diameter and has an umbilical diameter of 100 mm (0.28). 

Its body chamber, which occupies three-fourths of a 

whorl, has a diameter of 205 mm at its base. Seven umbilical bullae are present on the last one-half whorl. Part of 

the outer whorl of another large specimen, USNM 456669 

(fig. 1, loc. 10), which is of comparable size, has a whorl 

breadth of 124 mm and a whorl height of 116 mm 

(Wb:Wh=l.07) at the base of the body chamber. Ornament is absent except for faint rectiradiate bullae on the 

lower part of the flank. A smaller macroconch, USNM 

456670 (fig. 1, loc. 10), has a diameter of 157.0 mm at the 

base of the body chamber, an umbilical diameter of 37.7 

mm (0.24}, a whorl breadth of 97.0 mm (0.62), a whorl 

height of 72.0 mm (0.46), and a Wb:Wh ratio of 1.35. 

Weak ribs present on the last part of the phragmocone 

become weaker and disappear on the older one-quarter 

whorl of the body chamber. Umbilical bullae, numbering 

six per one-half whorl, persist on the body chamber. 

A small, nearly complete macroconch (USNM 

456668) from USGS Mesozoic locality 1725 (fig. 1, loc. 

16) shows the growth stages of the outer whorls of the 

phragmocone and body chamber. The specimen has a 

maximum diameter of 185.0 mm, a large umbilical diameter of 51.2 mm (0.28), a whorl breadth of 93.6 mm (0.51), 

a whorl height of 58.0 mm (0.31}, and a Wb:Wh ratio of 

1.61. The phragmocone has a diameter of 125.0 mm at the 

larger end, an umbilical diameter of 30.7 mm (0.25), a 

whorl breadth of 70.4 mm (0.56), a whorl height of 58.3 

mm (0.47), and a Wb:Wh ratio of 1.21. Ribs are strong, 

narrow, rectiradiate to slightly prorsiradiate, and number 

about 11 per one-half whorl to a diameter of about 75 

mm, where they greatly weaken. Out to this diameter, the 

ribs begin in pairs from prominent umbilical bullae or 

singly from between them. There are five bullae per onehalf whorl. At a diameter of 80-90 mm, ribs have 
SYSTEMATIC DESCRIPTIONS 7 

Table 3. Dimensions and features of Menuites portlocki complexus from the Baculites reduncus zone of the Rock River Formation near 

Rock River, Wyo. 

[Abbreviations of features: D. shell diameter; U, umbilical diameter; Wb, whorl breadth; Wh, whorl height. Quantities in parentheses are ratios of measurements to shell diameter; 

query(?), identification uncertain; leaders( .... ), no measurement] 

USNM Umbilical nodes Ribs per Macroconch (M) 

Specimen D u Wb Wh Wb:Wh per half whorl half whorl or microconch (m) 

456648 21.4 5.3 (0.25) 15.3 (0.71) 11.5 (0.54) 1.33 6 14 ? 

456649 48.7 10.3 (0.21) 30.3 (0.62) 22.2 (0.46) 1.36 5 13 M(?) 

456650 59.2 14.0 (0.24) 36.8 (0.62) 28.4 (0.48) 1.30 6 11 m 

456651 53.7 11.6 (0.22) 33.6 (0.63) 24.5 (0.46) 1.37 5 10 M 

456652 60.3 14.5 (0.24) 38.0 (0.63) 28.3 (0.47) 1.34 6 16 M 

456653 65.3 14.3 (0.22) 40.5 (0.62) 32.8 (0.50) 1.23 6 13 M 

456654 63.9 13.6 (0.21) 47.2 (0.74) 31.6 (0.49) 1.49 5 14 M 

456655 68.6 15.2 (0.22) 6 9 m 

456656 71.0 17.1 (0.24) 44.4 (0.63) 33.7 (0.47) 1.32 5 10 M 

456657 76.5 17.0 (0.22) 45.3 (0.59) 37.7 (0.49) 1.20 6 14 M 

456658 80.9 19.7 (0.24) 38.5 (0.48) 37.0 (0.46) 1.04 6 8 m 

456659 81.3 19.8 (0.24) 42.4 (0.52) 39.3 (0.48) 1.08 5 m 

456660 80.7 20.1 (0.25) 40.2 (0.50) 34.3 (0.43) 1.17 5 13 M 

456661 87.2 20.8 (0.24) 51.9 (0.60) 39.7 (0.46) 1.31 5 11 M 

456662 110.3 27.6 (0.25) 54.3 (0.49) 48.8 (0.44) 1.11 7 m 

456663 103.8 25.0 (0.24) 57.8 (0.56) 47.4 (0.46) 1.22 6 0 M 

456664 88.2 20.8 (0.24) 56.6 (0.64) 41.4 (0.47) 1.37 5 15 M 

456665 138.0 32.5 (0.24) 83.2 (0.60) 66.1 (0.48) 1.26 5 11 M 

456666 196.0 49.0 (0.25) 

disappeared and the umbilical bullae have weakened. All 

ornament is absent on the body chamber, which occupies 

half a whorl. 

The suture of M. portlocki complexus is deeply 

incised and has a broad external lobe, a smaller bifid lateral lobe with a very narrow stem, and a smaller bifid 

umbilical lobe (fig. 2). Hall and Meek (1856, pl. 4, figs. 

1d-f) illustrated a juvenile suture and parts of an adult 

suture. Meek (1876, pl. 24, fig. 1c) also showed the suture 

of a larger juvenile. 

Discussion.-Menuites portlocki complexus (Hall and 

Meek, 1856) is regarded herein as a geographic subspecies 

of M. portlocki (Sharpe, 1855, p. 30, pl. 13, figs. 2, 3). 

Sharpe described and illustrated a juvenile coil and most 

of an adult from the "Chalk of Tamlaght, in the county of 

Derry" in northern Ireland. The adult, designated the lectotype by Wright and Wright (1951, p. 36), is IGS 37247, 

the original of Sharpe (1855, pl. 13, fig. 2). The juvenile 

coil is a paralectotype, the original of Sharpe (1855, pl. 

13, fig. 3). Both are from the European upper Campanian 

0 0 M 

Belemnitella mucronata zone. The juvenile coil is about 

51.0 mm in diameter and has an umbilical diameter of 

14.4 mm (0.28), a whorl breadth of 32.8 mm (0.64), a 

whorl height of 24.0 mm (0.47), and a Wb:Wh ratio of 

1.37 (measurements from a plaster cast). It differs from M. 

portlocki complexus chiefly in being more evolute (umbilical diameter ratio of 0.28, compared to 0.17--0.25 for M. 

portlocki complexus). There are 5 umbilical tubercles and 

11 ribs per one-half whorl, which is comparable to 

similar-sized whorls of M. portlocki complexus (tables 2, 

3). There is no difference between the flat-topped, bullate 

umbilical tubercles and the strong, narrow ribs of the 

paralectotype and the Western Interior subspecies. The 

lectotype is a robust specimen that has a diameter of about 

84.2 mm, an umbilical diameter of 22.3 mm (0.26), a 

whorl breadth of 54.2 mm (0.64), a whorl height of 39.3 

mm (0.47), and a Wb:Wh ratio of 1.38 (measurements 

from a plaster cast). It is slightly more evolute than the 

Western Interior subspecies (table 3) and has more widely 

spaced umbilical tubercles (four per one-half whorl). The 
8 UPPER CRETACEOUS DIMORPHIC PACHYDISCID AMMONITE MENUITES IN THE WESTERN INTERIOR 

Figure 2. External suture, about four times actual size, of Menuites portlocki complexus (Hall and Meek, 1856). Hypotype USNM 

456653 from the Pierre Shale at USGS Mesozoic locality D1923 (fig. 1, loc. 3). E is the external or siphonallobe, Lis the lateral lobe, and 

U1 and U2 are the umbilical lobes. 

lectotype is a microconch that has the ventrolateral tubercles arising at a diameter of 77 mm (compared to 51--69 

mm forM. portlocki complexus). 

Menuites portlocki complexus differs from the Polish 

M. portlocki posterior (Bfaszkiewicz, 1980, p. 48, pl. 33, 

figs. 1, 2; pl. 34, figs. 5, 6; pl. 39, figs. 2, 3, 5, 8, 10, 11; 

pl. 40, figs. 1-4, 9-11; pl. 41, figs. 1-6) in having more 

inflated flanks and in having whorls broader than they are 

high. Menuites stephensoni Young (1963, p. 57, pl. 15, 

figs. 1, 2; text figs. 7o, 9n), known only from a microconch from the Taylor Group of Texas, retains ribbing and 

ventrolateral tuberculation over the entire body chamber. 

Occurrence.-Juveniles and inner whorls of M. portlocki complexus are fairly abundant in the Baculites gregoryensis zone of the Gregory Member of the Pierre Shale 

in the Chamberlain-Great Bend area in south-central South 

Dakota (fig. 1 ), where the subspecies was recorded as 

Pachydiscus complexus (Gries and Rothrock, 1941, p.l4; 

Wing and Gries, 1941, p. 14; Gries, 1942, p. 12). A single 

specimen was found in the Pierre Shale in South Dakota 

near the intersection of South Dakota, Montana, and Wyoming (fig. 1), and several specimens were found farther 

south in easternmost Wyoming in the upper part of the 

Red Bird Silty Member of the Pierre Shale (Gill and Cobban, 1966, p. A56, A57, listed as Anapachydiscus complexus). Many specimens have been collected from 

sandstone concretions in an 8-m-thick, ridge-forming 

sandstone unit 188 m above the base of the Rock River 

Formation near Rock River in southeastern Wyoming (fig. 

I, locs. 9-18) (Gill and others, 1970, p. 23; Toots, 1961, 

p. 165). The specimens, recorded as Anapachydiscus n. sp. 

and Menuites n. sp., were associated with a baculite 

recorded as Baculites n. sp. The baculite was later named 

B. reduncus Cobban (1977) and ranked as a zonal fossil 

between the zones of B. gregoryensis and B. scotti. The 

presence of M. portlocki complexus in the zone of B. 

reduncus in southeastern Wyoming, as well as in the zone 

of B. gregoryensis in south-central South Dakota, suggests 

that the two zones are contemporaneous and that B. reduncus occupied a nearshore environment west of the deeper 

water environment of B. gregoryensis. Menuites portlocki 

complexus has also been found south of Rock River and in 

an area about midway between Rock River and Cheyenne 

(fig. 1). 

Menuites portlocki complexus has been found at 

many localities in Colorado. Specimens have been collected from the lower part of the Hygiene Sandstone 

Member of the Pierre Shale in the Denver-Fort Collins 

area (Scott and Cobban, 1959, p. 126, listed as Anapachydiscus; Scott, 1963, p. 101; and Scott and Cobban, 1965, 

p. 2; the last two listed as Anapachydiscus? complexus and 

Menuites? n. sp.). Farther south, in the Colorado SpringsPueblo area, rocks equivalent to the Hygiene Sandstone 

Member are included in the upper part of the Rusty zone 
SYSTEMATIC DESCRIPTIONS 9 

of Gilbert (1897); M. portlocki complexus occurs in this 

part of the Pierre Shale (Scott and Cobban, 1986, listed as 

Anapachydiscus? complexus and Menuites? n. sp.). The 

subspecies has also been found in the Hygiene Sandstone 

Member north and east of Kremmling (lzett and others, 

1971, p. A8, listed as Menuites n. sp.; Izett, 1974, listed as 

Menuites n. sp.). In the Aspen area, a few specimens were 

collected from above the middle of the Mancos Shale. The 

subspecies has also been found in the Sego Sandstone in 

eastern Utah (fig. 1). 

Menuites oralensis n. sp. 

Plate4,figures 1-3; plate 5, figures 2-4; plate 6, figures 1-8; plate 7, figures 

1-4; plate 8, figures 1, 2, 5-7; plates 9-14; 

text figure 6 

1937 Parapachydiscus complexus (Hall and Meek). Dane and others, 

p. 230. 

1952 Pachydiscus complexus (Hall and Meek). Cobban and Reeside, 

p. 1020 (part). 

1959 Anapachydiscus [complexus Hall and Meek]. Scott and Cobban, 

p. 126 (part). 

1963 Anapachydiscus? complexus (Hall and Meek). Scott, p. 102, 103 

(part). 

1963 Menuites? n. sp. Scott, p. 102, 103 (part). 

1966 Anapachydiscus complexus (Hall and Meek). Gill and Cobban, 

p. A56 (part). 

1966 Menuites n. sp. Gill and Cobban, p. A56. 

1975 Menuites sp. Hirsch, p. 112, fig. 11 (not fig. 10). 

Types.-The holotype is USNM 456671 from the 

Red Bird Silty Member of the Pierre Shale at USGS 

Mesozoic locality 01411, which is a bluff along the Cheyenne River near Oral, S. Dak. (fig. 1, loc. 6). Paratypes are 

USNM 456672-456693 from the Pierre Shale at USGS 

Mesozoic localities D903, 01411, and 10385 in Fall River 

County, S. Dak.. (fig. 1, locs. 5-7), and D715 near Pueblo 

in Pueblo County, Colo. (fig. 1, loc. 20). 

Diagnosis.-Innermost whorls of this species have 

15-30 ribs per one-half whorl. The ribs are mostly weak 

and irregular in height, and are weak or absent on body 

chambers of microconchs, but they appear or become rejuvenated near the aperture. Strong nodal ventrolateral 

tubercles are present on the older halves of body chambers 

of microconchs but are absent on the younger halves. 

Macroconchs attain large sizes, have somewhat compressed whorls a little broader than they are high, and lack 

ribs and umbilical tubercles on adult body chambers. 

Description.-The holotype (pl. 10, figs. 1-3), a 

microconch 87.5 mm in diameter, has an umbilical diameter of 20.0 mm (0.23), a whorl breadth of 44.0 mm (0.5), a 

whorl height of 38.4 mm (0.44), and a Wb:Wh of 1.15. 

The moderately deep umbilicus has a vertical wall and a 

narrowly rounded shoulder. Whorls are stout and are 

broadest at the umbilical shoulder; flanks are very broadly 

rounded, whereas the venter is more narrowly rounded. 

The body chamber occupies about 60 percent of the outer 

whorl. The aperture is normal and follows the course of 

growth lines and ribs. Prominent, flat-topped umbilical 

bullae, five per one-half whorl, are located on the umbilical shoulder of the inner whorls but migrate onto the 

lower part of the flank on the outer whorl (pl. 10, fig. 2). 

The bullae disappear rather abruptly half way across the 

body chamber. On the last half of the phragmocone, ribs 

are irregular in height and spring in pairs from the umbilical bullae or arise singly from between them. Ribs are narrow and rectiradiate at first but then bend forward a little 

and cross the venter with a slight forward arching. Ribs 

weaken greatly near the end of the phragmocone and 

mostly disappear on the older part of the body chamber. 

Large, matched nodal ventrolateral tubercles appear suddenly near the end of the phragmocone and persist on the 

older half of the body chamber before abruptly disappearing. There are five of these paired ventrolateral tubercles. 

Two of them are joined to umbilical bullae by looped ribs. 

All tubercles are absent on most of the younger half of the 

body chamber, where ornament consists mainly of irregular lirae and growth lines. Ornament is rejuvenated near 

the end of the body chamber (pl. 10, fig. 2), where several 

narrow ribs arise from narrow, low umbilical bullae or 

from between them. The ribs slant forward a little on 

crossing the flank and then bend forward and cross the 

venter convexly. 

Microconchs of Menuites oralensis n. sp. from the 

type area (Oral area in Fall River County, S. Dak..) avail-: 

able for study include 52 adults suitable for measurement 

of the diameter at the base of the body chamber. The 

diameters range from 32.0 to 63.5 mm; most are in the 50-

to 58-mm range (fig. 3). Umbilical ratios, which can be 

determined for 30 of the specimens, range from 0.17 to 

0.26 (fig. 4). Ribs per one-half whorl on the outer whorl 

of the phragmocone range from 15 to 32. Like those of the 

holotype, ribs tend to be of unequal strength and weaken 

greatly near the base of the body chamber. Ribs are usually absent over much of the older half of the body chamber except for weak looped ribs that may connect 

umbilical bullae to ventrolateral tubercles (pl. 11, figs. 2, 

8; pl. 12, fig. 2). An occasional individual may have both 

weak and strong ribs on all of the body chamber (pl. 11, 

fig. 6). Rejuvenated ribbing near the aperture consists usually of two to four strong, narrow prorsiradiate ribs that 

arch forward a little upon crossing the venter (pl. 11, figs. 

6, 11; pl. 12, fig. 2). These ribs generally begin on the 

umbilical shoulder and attain their greatest height on the 

middle of the venter. The broad interspaces that separate 

the ribs may be smooth or may contain very weak ribs. 

Rare specimens have as many as seven or eight strong, 

narrow rejuvenated ribs (pl. 7, figs. 1-3) that appear 

abruptly following the disappearance of the ventrolateral 

tubercles. Ventrolateral tubercles are large and usually 

nodal (pl. 12, figs. 1, 2, 5, 6), although some may be 
10 UPPER CRETACEOUS DIMORPHIC PACHYDISCID AMMONITE MENUITES IN THE WESTERN INTERIOR 

somewhat clavate (pl. 11, figs. 1-3, 8, 9), and the initial 

ones on the phragmocone are generally bullate. The tubercles arise rather abruptly near the end of the phragmocone 

and continue on the older two-thirds of the body chamber. 

The tubercles are either paired (pl. 10, fig. 1; pl. 11, figs. 

3-5), alternated (pl. 11, fig. 9; pl. 12, figs. 1, 6), or both 

paired and alternated (pl. 11, fig. 10). 

Macroconchs of Menuites oralensis n. sp. from the 

Oral area attain diameters of as much as 224 mm (pl. 14 ). 

Inner whorls of less than 50 mm in diameter are like those 

of microconchs in that they have similar umbilical diameters and whorl sections (fig. 5) as well as similar ribs of 

irregular height (pl. 4, figs. 1-3). The ribs number 15-34 

per one-half whorl and mostly disappear at a diameter of 

90-100 mm (pl. 13). Flat-topped umbilical bullae, numbering five to six per one-half whorl, are present on these early 

whorls (pl. 4, fig. 2), but they weaken and disappear at a 

diameter of 60-90 mm. By a diameter of about 110 mm, 

flanks on the macroconchs have flattened somewhat, and 

the shell is mostly smooth except for growth lines and low, 

obscure ribs that are mainly visible on the venter (pl. 13, 

figs. 2, 5). At larger diameters, the shell may have only 

growth lines (pl. 8, fig. 7; pl. 14). The suture (fig. 6) is 

complexly incised like that of M. portlocki complexus (Hall 

and Meek). 

A fragment that represents the middle part of a huge 

phragmocone (USNM 433757) was recently collected by 

Peter Larson (Black Hills Institute of Geological Research) 

from the part of the Pierre Shale near Oral, S.Dak., that has 

yielded many M. oralensis n. sp. Most of one side of the 

specimen is well preserved, but the other side and venter 

are crushed. The whorl height is 236 mm. The specimen is 

smooth, has a well-rounded umbilical wall and shoulder, 

and has a flattened flank that merges evenly into a rounded 

venter. The specimen may represent an unusually large 

macroconch of M. oralensis n. sp. 

Discussion.-Menuites oralensis n. sp. differs from 

its ancestor M. portlocki complexus (Hall and Meek) in 

having weaker and denser ribbed inner whorls and a 

smaller and more compressed microconch. Menuites portlocki posterior Braszkiewicz (1980, p. 48, pl. 33, figs. 1, 

2; pl. 34, figs. 5, 6; pl. 39, figs. 2, 3, 5, 8, 10, 11; pl. 40, 

figs. 1-4, 9-11; pl. 41, figs. 1--6) is a slightly younger 

subspecies than M. portlocki portlocki and may be close to 

or the same age as M. oralensis. Menuites portlocki posterior Btaszkiewicz differs from M. oralensis in having 

coarsely ribbed inner whorls like those of M. portlocki 

portlocki and in having whorls higher than they are wide. 

Occurrence.-Menuites oralensis n. sp. is confined to 

the Baculites scotti zone of the Pierre Shale and equivalent 

rocks in the Western Interior. This zone is considered as 

the top of the middle Campanian in the Western Interior 

sequence (Cobban, in press). Menuites oralensis has been 

found in the middle part of the Pierre Shale in southeastern 

Montana and the adjacent part of South Dakota north of 

the Black Hills (fig. 1), and also in the basal part of the 

lower unnamed shale member of the Pierre Shale farther 

south along the west flank of the Black Hills in easternmost Wyoming, where the species was reported as Anapachydiscus sp., A. complexus (Hall and Meek), and 

Menuites n. sp. (Robinson and others, 1964, p. 91; Gill and 

Cobban, 1966, p. A56). Farther east, M. oralensis is fairly 

abundant in the Pierre Shale on the southeastern flank of 

the Black Hills uplift in the Oral area in Fall River County, 

S. Dak. (fig. 1, locs. 4-8). Here, the species is especially 

well preserved, with nacreous shells. Specimens have also 

10~~~~~--~~~~~--

9 

~ 8 w 

:2: 7 

u 

~ 6 

~ 5 

0 

a: 4 w 

a:! 3 

:2: 

~ 2 

34 38 42 46 50 54 58 62 66 

SHELL DIAMETER, IN MILLIMETERS 

Figure 3. Histogram showing range in base diameters of body chambers of 

52 Menuites oralensis n. sp. microconchs from the Pierre Shale in the Oral area 

in Fall River County, S. Dak. The microconchs are from USGS Mesozoic 

localities 0901,0903,01411,013159, and 10385 (fig. 1, locs. 4-8), from the 

collection of the Black Hills Institute of Geological Research and from the 

private collection of Steve Jorgensen, Fargo, N.Dak. 
SYSTEMATIC DESCRIPTIONS 11 

0.27 I I I I I I 

• 

Oo 

0.25 I1-- • • a:~ 

~a: • 

• -

Wa: 

:2:w • • • <(I- -W 0:2: •• • • 

-1<( <(- 0.20 f.- • • •• ••• uo -

-...J 

::::!-.~ •• • • • alW 

:2:::I: • • • • :JCJ) 

• • 

0.15L---------~I __________ _LI ___________ L_I ________ ~I----------~'-----------L-I ________ ~ 

35 40 45 50 55 60 65 70 

SHELL DIAMETER, IN MILLIMETERS 

Figure 4. Scatter diagram showing umbilical- to shell-diameter ratio as a function of shell diameter for 30 Menuites oralensis n. sp. microconchs from the Pierre Shale of the Oral area in Fall River County, S. Dak. Specimens are from USGS Mesozoic localities D901, 0903, 

D1411, D13159, and 10385 (fig. 1, locs. 4-8) from the collection of the Black Hills Institute of Geological Research and from the private 

collection of Steve Jorgensen, Fargo, N. Dak. 

2.0~------~,------~~------~~--------~~------~~------~l--------,~------~,------.-,------, 

0 

~ 

~ 1.5-

:I: 

(!) 

jjj 

:I: 

6 ± 1.0 II0 

<( 

w 

a: 

OJ 

~ 0.5 1--

0 

:I: 

~ 

• 0 0 

0 

0 0 

0 

• 

0 

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-

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O.OL-------L-'------~~------~I ________ L_I ______ L_I ______ JI ______ ~IL_ ______ L_I ______ ~I----~ 

30 40 50 60 70 80 90 100 110 120 130 

SHELL DIAMETER, IN MILLIMETERS 

Figure 5. Scatter diagram showing whorl breadth-to-height ratio as a function of shell diameter for 44 specimens of Menuites oralensis 

n. sp. from the Pierre Shale of the Oral area in Fall River County, S.Dak. Circles are microconchs and dots are macroconchs. Specimens 

are from USGS Mesozoic localities D901, D903, D1411. D13159, and 10385 (fig. 1, locs. 4-8) and from the collection of the Black Hills 

Institute of Geological Research. 

been found farther north near Rapid City, S. Dale In westcentral Wyoming, a few specimens have been collected 

from an unnamed tongue of marine shale in the Mesaverde 

Formation near Casper and from farther north (W egemann, 

1911, p. 51, listed as Pachydiscus complexus; Gill and 

Burkholder, 1979, p. 186). A few specimens were also 

found in a sandy unit of the Pierre Shale northwest of 

Cheyenne in southeastern Wyoming (Scott and Cobban, 

1959, p. 129). 

Menuites oralensis has been found in the Pierre Shale 

at many localities in the Denver-Canon City-Pueblo area 

in central Colorado (Scott and Cobban, 1965, 1975, 1986). 

One collection (D715) from Pueblo (fig. 1, loc. 20) contains 80 macroconchs and 40 microconchs. This is the 

locality that yielded 154 specimens of Baculites scotti 

(Cobban, 1958, p. 660) from a part of the Pierre Shale 

described as the Rusty zone by Gilbert (1897). The Menuites from this locality were listed as Anapachydiscus? 
12 UPPER CRETACEOUS DIMORPHIC PACHYDISCID AMMONITE MENUITES IN THE WESTERN INTERIOR 

Figure 6. External suture of Menuites oralensis n. sp. Paratype USNM 456669 from the Pierre Shale at USGS Mesozoic locality D903 

(fig. 1, loc. 5). Figure is about 3th times actual size. E is the external or siphonallobe, Lis the lateral lobe, and U1 and U2 are the umbilical 

lobes. 

complexus and Menuites? n. sp. by Scott (1964, 1969). In 

the Denver area, M. oralensis occurs in the Hygiene Sandstone Member of the Pierre Shale (Scott and Cobban, 

1965, listed as Anapachydiscus? complexus and Menuites? 

n. sp.). Farther west, in the Kremmling area, M. oralensis 

also occurs in the Hygiene Member (lzett and others, 

1971, p. A14, listed as A. complexus). Farther north, in 

North Park, a few specimens of M. oralensis have been 

found in the Pierre Shale. To the west, Menuites oralensis 

occurs in the Mancos Shale of the Glenwood SpringsGrand Junction area and in the Lewis Shale southwest of 

Montrose. The only known occurrence of the species in 

New Mexico is from the Lewis Shale near El Vado (Cobban and others, 1974, p. 280), where it was recorded as 

Anapachydiscus sp. 

REFERENCES CITED 

Braszkiewicz, Andrzej, 1980, Campanian and Maastrichtian ammonites of the middle Vistula Valley, Poland-a stratigraphicpaleontologic study: Prace Instytutu Geologicznego, v. 92, 63 

p., 56 pis. 

Boyle, C.B., 1893, A catalogue and bibliography of North American Mesozoic Invertebrata: U.S. Geological Survey Bulletin 

102,315 p. 

Cobban, W.A., 1958, Two new species of Baculites from the Western Interior region: Journal of Paleontology, v. 32, p. 660--665, 

pls. 90, 91. 

--1977, A new curved baculite from the Upper Cretaceous of 

Wyoming: Journal of Research of the U.S. Geological Survey, 

v.5,no.4,p.457--462. 

--in press, Diversity and distribution of Late Cretaceous ammonites, Western Interior, United States: Geological Association of Canada Special Paper 39. 

Cobban, W.A., Landis, E.R., and Dane, C.H., 1974, Age relations 

of upper part of Lewis Shale on east side of San Juan Basin, 

New Mexico, 1974: Ghost Ranch, N. Mex., New Mexico Geological Society, 25th field conference, Guidebook, p. 279-282. 

Cobban, W.A., and Reeside, J.B., Jr., 1952, Correlation of the 

Cretaceous formations of the Western Interior of the United 

States: Geological Society of America Bulletin, v. 63, no. 10, 

p. 1011-1043, 1 pl. 

Collignon, Maurice, 1931, Faunes Senoniennes du Nord et de 

l'Ouest de Madagascar: Annales Geologiques du Service des 

Mines de Madagascar, pt. 1, p. 1-64, pis. 1-9. 

Dane, C.H., Pierce, W.O., and Reeside, J.B., Jr., 1937, The stratigraphy of the Upper Cretaceous rocks north of the Arkansas 

River in eastern Colorado: U.S. Geological Survey Professional Paper 186-K, p. 207-232, pis. 64, 65. 

Diener, Carl, 1925, Ammonoidea neocretacea, pt. 29 of Animalia, 

pt. 1, in Diener, Carl, ed., Fossilium catalogus: Berlin, W. 

Junk, 244 p. 
REFERENCES CITED 13 

Forbes, Edward, 1846, Report on the fossil Invertebrata from southem India, collected by Mr. Kaye and Mr. Cunliffe: Transactions of the Geological Society of London, 2d ser., v. 7, pt. 3, 

p. 97-174, pis. 7-19. 

Gabb, W.M., 1861, Synopsis of the mollusca of the Cretaceous 

Formation, including the stratigraphic range and synonymy: 

Proceedings of the American Philosophical Society, v. 8, p. 

57-257. 

Gardner, J.A., 1916, Mollusca in Upper Cretaceous: Baltimore, 

Md., Maryland Geological Survey, Johns Hopkins Press, p. 

371-733, pis. 12-45. 

Gilbert, O.K., 1897, Description of the Pueblo quadrangle [Colorado]: U.S. Geological Survey Geologic Atlas, Folio 36. 

Gill, J.R., and Burkholder, R.E., 1979, Measured sections of the 

Montana Group and equivalent rocks from Montana and Wyoming: U.S. Geological Survey Open-File Report 79-1143, 

202p. 

Gill, J.R., and Cobban, W.A., 1966, The Red Bird section of the 

Upper Cretaceous Pierre Shale in Wyoming, with a section on 

A new echinoid from the Cretaceous Pierre Shale of eastern 

Wyoming, by P.M. Kier: U.S. Geological Survey Professional 

Paper 393-A, p. Al-A 73. 

Gill, J.R., Merewether, E.A., and Cobban, W.A., 1970, Stratigraphy and nomenclature of some Upper Cretaceous and lower 

Tertiary rocks in south-central Wyoming: U.S. Geological Survey Professional Paper 667, 50 p. 

Grabau, A.W., and Shimer, H.W., 1910, North American index fossils; invertebrates, v. 2: New York, A.S. Seiler and Co., 909 p. 

Gries, J.P., 1942, Economic possibilities of the Pierre Shale: South 

Dakota Geological Survey Report of Investigations 43, 79 p. 

Gries, J.P., and Rothrock, E.P., 1941, Manganese deposits of the 

lower Missouri Valley in South Dakota: South Dakota Geological Survey Report of Investigations 38, 96 p. 

Hall, James, and Meek, F.B., 1856, Descriptions of new species of 

fossils from the Cretaceous formations of Nebraska, with observations upon Baculites ovatus and B. compressus, and the 

progressive development of the septa in Baculites,Ammonites, 

and Scaphites: American Academy of Arts and Science Memoir, new ser., v. 5, p. 379-411, pls. 1-8. 

Hirsch, K.F., 1975, Die Ammoniten des Pierre Meeres (Oberkreide) in den westlichen USA: Der Aufschluss, Jahrgang 26, 

no. 3, p. 102-113, 11 figs. 

Izett, G.A., 1974, Geologic map of the Trail Mountain quadrangle, 

Grand County, Colorado: U.S. Geological Survey Geologic 

Quadrangle Map GQ-1156, scale I :24,000. 

Izett, G.A., Cobban, W.A., and Gill, J.R., 1971, The Pierre Shale 

near Kremmling, Colorado, and its correlation to the east and 

the west: U.S. Geological Survey Professional Paper 684-A, 

19 p. 

Kennedy, W.J., 1986, Campanian and Maastrichtian ammonites 

from northern Aquitaine, France: [London] Palaeontological 

Association Special Papers in Palaeontology 36, 145 p., 23 pls. 

Kennedy, W.J., and Cobban, W.A., 1976, Aspects of ammonite 

biology, biogeography and biostratigraphy: [London] Palaeontological Association Special Papers in Palaeontology, no. 17, 

94 p., 11 pis. 

Kennedy, W.J., and Summesberger, H., 1984, Upper Campanian 

ammonites from the Gschliefgraben (Ultrahelvetic, Upper 

Austria): Beitrage zur Palaontologie von Osterreich, no. 11, 

p. 149-206, pis. 1-14. 

Matsumoto, Tatsuro, 1984, Some ammonites from the Campanian 

(Upper Cretaceous) of northern Hokkaido: Palaeontological 

Society of Japan, Special Paper 27, p. 5-32, pis. 1-9. 

Meek, F.B., 1864, Check list of the invertebrate fossils of North 

America; Cretaceous and Jurassic: Smithsonian Miscellaneous 

Collections 177, 40 p. 

---1876, A report on the invertebrate Cretaceous and Tertiary 

fossils of the upper Missouri country: U.S. Geological Survey 

of the Territories (Hayden) Report 9, 629 p., 45 pis. 

Reeside, J.B., Jr., 1962, Cretaceous ammonites of New Jersey, pt. 

2 of The Cretaceous fossils of New Jersey: New Jersey 

Bureau of Geology and Topography Bulletin 61, p. 113-137, 

pls. 68-75. 

Robinson, C.S., Mapel, W.J., and Bergendahl, M.H., 1964, Stratigraphy and structure of the northern and western flanks of the 

Black Hills uplift, Wyoming, Montana, and South Dakota: 

U.S. Geological Survey Professional Paper 404, 134 p. 

Schultz, L.G., 1965, Mineralogy and stratigraphy of the lower part 

of the Pierre Shale, South Dakota and Nebraska: U.S. Geological Survey Professional Paper 392-B, p. B1-Bl9. 

Scott, G.R., 1963, Bedrock geology of the Kassler quadrangle, 

Colorado: U.S. Geological Survey Professional Paper 421-B, 

p. 71-125. 

---1964, Geology of the northwest and northeast Pueblo quadrangles, Colorado: U.S. Geological Survey Miscellaneous 

Geologic Investigations Map 1-408, scale I :24,000. 

---1969, General and engineering geology of the northern part 

of Pueblo, Colorado: U.S. Geological Survey Bulletin 1262, 

131 p. 

Scott, G.R., and Cobban, W.A., 1959, So-called Hygiene Group of 

northeastern Colorado, in Washakie, Sand Wash, and Piceance 

Basins, 1959: Rocky Mountain Association of Geologists, II th 

annual field conference, Guidebook, p. 124-131. 

---1965, Geologic and biostratigraphic map of the Pierre Shale 

between Jarre Creek and Loveland, Colorado: U.S. Geological 

Survey Miscellaneous Geologic Investigations Map 1-439, 

scale I :48,000. 

---1975, Geologic and biostratigraphic map of the Pierre Shale 

in the Canon City-Florence Basin and the Twelvemile Park 

area, south-central Colorado: U.S. Geological Survey Miscellaneous Investigations Series Map 1-937, scale 1 :48,000. 

---1986, Geologic and biostratigraphic map of the Pierre Shale 

in the Colorado Springs-Pueblo area, Colorado: U.S. Geological Survey Miscellaneous Investigations Series Map 1-1627, 

scale 1: 100,000. 

Sharpe, Daniel, 1854 [1855], Description of the fossil remains of 

Mollusca found in the Chalk of England: [London] Palaeontographical Society Monograph [pt. 2], p. 27-36, pls. 11-16. 

Spath, L.F., 1922, On the Senonian ammonite fauna ofPondoland: 

Transactions of the Royal Society of South Africa, v. 10, pt. 3, 

p. 113-147, pis. 5-9. 

Toots, Heinrich, 1961, Beach indicators in the Mesaverde Formation in Green River, Wind River, and Powder River Basins, 

1961: Wyoming Geological Association, 16th annual field 

conference, Guidebook, p. 165-170. 

Wegemann, C.H., 1911, The Salt Creek oil field, Natrona County 

[Wyoming]: U.S. Geological Survey Bulletin 452, p. 37-87. 
14 UPPER CRETACEOUS DIMORPHIC PACHYDISCID AMMONITE MENUITES IN THE WESTERN INTERIOR 

Weller, Stuart, 1907, A report on the Cretaceous paleontology of 

New Jersey, based upon the stratigraphic studies of George 

N. Knapp: Geological Survey of New Jersey, Paleontology 

Series, v. 4, 1106 p., 111 pis. 

Wing, M.E., and Gries, J.P., 1941, Stratigraphy and structure of the 

Chamberlain section of the Missouri River Valley: South 

Dakota Geological Survey Report of Investigations 39, 72 p. 

Wright, C.W., and Wright, E.V., 1951, A survey of the fossil Cephalopoda of the Chalk of Great Britain: [London] Palaeontographical Society Monograph, 40 p. 

Published in Central Region, Denver, Colo. 

Manuscript approved for publication September 15, 1992 

Yabe, Hisakatsu, and Shimizu, Saburo, 1921, Notes on some Cretaceous ammonites from Japan and California: Science Reports of the Tohoku Imperial University, 2d ser. (Geology), v. 

5, no. 3, p. 53-59, pis. 8, 9. 

---1926, A study of the genus "Parapachydiscus" Hyatt: Proceedings of the Imperial Academy of Japan, v. 2, p. 171-173. 

Young, Keith, 1963, Upper Cretaceous ammonites from the Gulf 

Coast of the United States: Texas University Publication 6304, 

373 p., 82 pis. 
PLATES 

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

Federal Center, Denver, CO 80225 
PLATE 1 

[All figures natural size. Arrows point to base of body chambers] 

Figures 1-11. Menuites portlocki complexus (Hall and Meek) (p. 2). 

1, 2. Hypotype USNM 456649, from USGS Mesozoic locality 013161 

(text fig. 1, loc. 15). 

3-5. Hypotype USNM 456650, from the same locality. 

6-8. Hypotype USNM 456655, from USGS Mesozoic locality 1725 

(text fig. 1, loc. 16). 

9-11. Hypotype USNM 456659, from the same locality as figures 1-5. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 PLATE 1 

MENUITES PORTLOCK! COMPLEXUS 
PLATE 2 

[All figures natural size] 

Figures 1-5. Menuites portlocki complexus (Hall and Meek) (p. 2). 

1-3. Hypotype USNM 456661, from USGS Mesozoic locality 12844 

(text fig. 1, loc. 9). 

4, 5. Hypotype USNM 456665, from USGS Mesozoic locality 1725 

(text fig. 1, loc. 16). 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 PLATE 2 

3 

1 

2 

··- • 

I _) 

I 

4 5 

MENUITES PORTLOCK! COMPLEXUS 
PLATE 3 

[Figure is natural size. Arrow points to base of body chamber] 

Menuites portlocki complexus (Hall and Meek) (p. 2). 

Hypotype USNM 456666, from USGS Mesozoic locality 01922 (text fig. 1, loc. 2). 
U S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 PLATE 3 

._. . 

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,.. _,.._ - "' --

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..

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MENUJTES PORTLOCK! COMPLEXUS 
PLATE 4 

[All figures natural size. Arrows point to base of body chambers] 

Figures 1-3. Menuites oralensis n. sp. (p. 9). 

Paratype USNM 456672, from USGS Mesozoic locality D903 (text fig. 1, 

loc. 5). 

4-10. Menuites portlocki complexus (Hall and Meek) (p. 2). 

4, 5. Hypotype USNM 456652, from USGS Mesozoic locality 12844 

(text fig. 1, loc. 9). 

6. Hypotype USNM 456660, from USGS Mesozoic locality Dl3161 

(text fig. 1, loc. 15). 

7, 8. Hypotype USNM 456656, from USGS Mesozoic locality D1922 

(text fig. 1, loc. 2). 

9, 10. Hypotype USNM 456664, from USGS Mesozoic locality 12844 

(text fig. 1, loc. 9). 
5 

8 

PROFESSIONAL PAPER 1533 PLATE 4 

6 

I 

I 

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MENUITES ORALENSIS AND MENUITES PORTLOCK/ COMPLEXUS 

4 

7 

10 
PLATE 5 

[All figures natural size. Arrows point to base of body chambers) 

Figures 1, 5-7. Menuites portlocki complexus (Hall and Meek) (p. 2). 

1. Hypotype USNM 456654, from USGS Mesozoic locality D297 

(text fig. 1, loc. 19). 

5-7. Hypotype USNM 456663, from USGS Mesozoic locality D1923 

text fig. 1, Joe. 3). 

2-4. Menuites oralensis n. sp. (p. 9). 

Paratype USNM 456673, from USGS Mesozoic locality 10385 (text fig. 1, 

loc. 7). 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 PLATE 5 

6 

MENUITES PORTLOCK! COMPLEXUS AND MENUITES ORALENSIS 
PLATE 6 

[All figures natural size. Arrows poinllo base of body chambers] 

Figures 1-8. Menuites oralensis n. sp. (p. 9). 

1, 2. Paratype USNM 456674, from USGS Mesozoic locality D903 

(text fig. 1, Joe. 5). 

3-5. Paratype USNM 456675, from the same locality. 

6-8. Paratype USNM 456676, from USGS Mesozoic locality D1411 

(text fig. 1, Joe. 6). 

9-15. Menuites portlocki complexus (Hall and Meek) (p. 2). 

9, 10. Hypotype USNM 456651, from USGS Mesozoic locality D1392 

(text fig. 1, Joe. 13). 

11-13. Hypotype USNM 456657, from USGS Mesozoic locality 12844 

(text fig. 1, Joe. 9). 

14, 15. Hypotype USNM 456658, from USGS Mesozoic locality D13161 

text fig. 1, Joe. 15). 
U.S. GEOLOGICAL SURVEY 

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9 

13 

PROFESSIONAL PAPER 1533 PLATE 6 

3 5 

2 

11 12 

10 

14 15 

MENUITES ORALENSIS AND MENUITES PORTLOCK/ COMPLEXUS 
PLATE 7 

[All figures natural size. Arrows point to base of body chambers] 

Figures 1-4. Menuites oralensis n. sp. (p. 9). 

1-3. Paratype USNM 456677, from USGS Mesozoic locality D13160 

(text fig. 1, loc. 1). 

4. Paratype USNM 456678, from USGS Mesozoic locality Dl411 

(text fig. l, loc. 6). 

5. Menuites portlocki complexus (Hall and Meek) (p. 2). 

Hypotype USNM 456662, from USGS Mesozoic locality Dl082 (text fig. 1, 

loc. 17). 
U.S. GEOLOGICAL SURVEY 

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PROFESSIONAL PAPER 1533 PLATE 7 

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MENUITES ORALENSIS AND MENUITES PORTLOCK! COMPLEXUS 
PLATE 8 

[AU figures natural size. Arrows point to base of body chambers) 

Figures 1, 2, 5-7. Menuites oralensis n. sp. (p. 9). 

1, 2. Paratype USNM 456679, from USGS Mesozoic locality D1411 

(text fig. 1, loc. 6). 

5, 6. Paratype USNM 456680, from USGS Mesozoic locality D903 

(text fig. 1, loc. 5). 

7. Paratype USNM 456681, from USGS Mesozoic locality D1411 

(text fig. 1, loc. 6). 

3, 4. Menuites portlocki complexus (Hall and Meek) (p. 2). 

Hypotype USNM 456648, from USGS Mesozoic locality D13161 

(text fig. I, loc. 15). 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 PLATE 8 

/ 

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MENUITES ORALENS/S AND MENUITES PORTLOCK/ COMPLEXUS 
PLATE 9 

[Both figures natural size. Arrow points 10 base of body chamber) 

Figures I, 2. Menuites oralensis n. sp. (p. 9). 

Paratype USNM 456682, from USGS Mesozoic locality D715 (text fig. I, 

loc. 20). 
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PLATE 10 

[All figures natural size. Arrow points to base of body chamber) 

Figures 1-6. Menuites oralensis n. sp. (p. 9). 

1-3. Holotype USNM 456671, from USGS Mesozoic locality Dl411 

(text fig. I, Joe. 6). 

4-6. Paratype USNM 456683, from the same locality. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 PlATE 10 

1 2 3 

4 5 6 

MENUITES ORALENSIS 
PLATE 11 

[All figures natural size. Arrows point to base of body chambers] 

Figures 1-11. Menuites oralensis n. sp. (p. 9). 

1- 3. Paratype USNM 456684, from USGS Mesozoic locality D903 

(text fig. 1, loc. 5). 

4, 7. Paratype USNM 456685, from USGS Mesozoic locality D1411 

(text fig. 1, loc. 6). 

5, 6. Paratype USNM 456686, from the same locality as figures 1-3. 

8, 9. Paratype USNM 456687, from the same locality. 

10, 11. Paratype USNM 456684, from the same locality. 
U.S. GEOLOGICAL SURVEY 

8 

1 

;; 

9 

2 

10 

MENUITES ORALENSIS 

PROFESSIONAL PAPER 1533 PLATE 11 

3 4 

11 
PLATE 12 

[All figures natural size. Arrows point to base of body chambers) 

Figures 1-6. Menuites oralensis n. sp. (p. 9). 

1-3. Paratype USNM 456689, from USGS Mesozoic locality 0903 

(text fig. I, Joe. 5). 

4. Paratype USNM 456690, from USGS Mesozoic locality 0715 

(text fig. 1, Joe. 20). See plate 13, figures 1 and 2 for other views. 

5, 6. Paratype USNM 456691, from USGS Mesozoic locality 013159 

(text fig. 1, Joe. 8). 
U S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 PLATE 12 

2 3 

/ 

f 

4 5 6 

MENUITES ORALENSIS 
PLATE 13 

[All figures natural size. Arrows pointlo base of body chambers] 

Figures 1-5. Menuites oralensis n. sp. (p. 9). 

1, 2. Paratype USNM 456690, from USGS Mesozoic locality D715 (text 

fig. 1, Joe. 20). See plate 12, figure 4 for other view. 

3-5. Paratype USNM 456692, from USGS Mesozoic locality D903 (text 

fig. 1, Joe. 5). 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1533 PLATE 13 

~- . 

2 

3 

4 5 

MENUTTES ORALENSTS 
PLATE 14 

[Figure natural size I 

Menuites oralensis n. sp. (p. 9). 

Paratype USNM 456693, from USGS Mesozoic locality D903 (text fig. 1, loc. 5). 
U.S. GEOLOGICAL SURVEY 

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» U .S. GOVERNMENT PRINTING OFFICE: 1993- 774-049/66070 

PROFESSIONAL PAPER 1533 PLATE 14 

MENUITES ORALENSIS 

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State catalogs, "List of U.S. Geological Survey Geologic and Water-Supply Reports and Maps For (State);' may be purchased by mail and 

over the counter in paperback booklet form only. 

"Price and Availability List of U.S. Geological Survey Publications," issued annually, is available free of charge in paperback booklet 

form only. 

Selected copies of a monthly catalog "New Publications of the 

U.S. Geological Survey" is available free of charge by mail or may be 

obtained over the counter in paperback booklet form only. Those wishing 

a free subscription to the monthly catalog "New Publications of the U.S. 

Geological Survey" should write to the U.S. Geological Survey, 582 National Center, Reston, VA 22092. 

Note.-Prices of Government publications listed in older catalogs, 

announcements, and publications may be incorrect. Therefore, the prices 

charged may differ from the prices in catalogs, announcements, and publications. 
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