Stratigraphy and Paleontology of 

Mid-Cretaceous Rocks in Minnesota 

and Contiguous Areas 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 
Stratigraphy and Paleontology of 

Mid-Cretaceous Rocks in Minnesota 

and Contiguous Areas 

By WILLIAM A. COBBAN and E. A. MEREWETHER 

Molluscan Fossil Record from the Northeastern 

Part of the Upper Cretaceous Seaway, Western Interior 

By WILLIAM A. COBBAN 

Lower Upper Cretaceous Strata in Minnesota and 

Adjacent Areas-Time-Stratigraphic Correlations. 

and Structural Attitudes 

By E. A. M EREWETHER 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1 2 53 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1983 
UNITED STATES DEPARTMENT OF THE INTERIOR 

Library of Congress Cataloging in Publication Data 

Cobban, William Aubrey, 1916 

JAMES G. WATT, Secretary 

GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Stratigraphy and paleontology of mid-Cretaceous rocks in Minnesota and contiguous areas. 

(Geological Survey Professional Paper 1253) 

Bibliography: 52 p. 

Supt. of Docs. no.: I 19.16 

A. Molluscan fossil record from the northeastern part of the Upper Cretaceous seaway, Western Interior by William A. Cobban. B. Lower 

Upper Cretaceous strata in Minnesota and adjacent areas-time-stratigraphic correlations and structural attitudes by E. A. Merewether. 

I. Mollusks, Fossil-Middle West. 2. Geology, Stratigraphic-Cretaceous. 3. Geology-Middle West. 4. Paleontology-Cretaceous. 5. 

Paleontology-Middle West. I. Merewether, E. A. (Edward Allen), 1930. II. Title. III. Series. 

QE687.C6 551.7'7'09776 81--607803 AACR2 

For sale by the Distribution Branch, U.S. Geological Survey 

604 South Pickett Street, Alexandria, VA 22304 
CONTENTS 

[Letters designate chapters] 

Page 

(A) Molluscan fossil record from the northeastern part of the Upper Cretaceous seaway, 

Western Interior -----------------------------------------------------------------

(B) Lower Upper Cretaceous strata in Minnesota and adjacent areas-time-stratigraphic correlations and structural attitudes --------------------------------------------------- 27 

Molluscan Fossil Record from the 

Northeastern Part of the 

Upper Cretaceous Seaway, 

Western Interior 

By WILLIAM A. COBBAN 

STRATIGRAPHY. AND PALEONTOLOGY OF MID-CRETACEOUS 

ROCKS IN MINNESOTA AND CONTIGUOUS AREAS 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253-A 

Bivalves) ammonites) and a belemnite) from 

Cretaceous bedrock and from glacial deposits, 

represent at least 7 7 molluscan faunal zones of 

Cenomanian to Santonian age that are present or 

were present in Minnesota) eastern North and 

South Dakota, northeastern Nebraska, and Iowa 

CONTENTS 

Page 

Abstract - - - ---- --- --- --- -- - - --- -- -- - --- --- -- ---- -- - - --- - - --- --- - --- - - --- --- --- -- - - --- - 1 

Introduction - - -- - -- - - - - - -- - - -- -- - -- -- - -- - -- - -- - -- - -- - - - -- - -- - -- - - -- - - --- - - - -- - - - - -- - - - 1 

Acknowledgments --------------------------------------------------------------------- 3 

Important molluscan fossils ------------------------------------------------------------ 3 

Bivalves - - - -- -- - - - -- - - - - -- - -- - - -- - - -- - - - - - -- - -- - - - -- -- - - -- - - - -- - - -- -- - - -- - - -- - - - - - 3 

Family Inoceramidae --- -- --- - - --- --- -- -- -- --- --- --- --- - - --- - - - --- - - --- --- ---- - 3 

Genus Inoceramus--------------------------------------------------------- 3 

Genus Mytiloides -------------------------------------------------------- - 6 

Genus Platyceramus ------------------------------------------------------- 7 

Genus Volviceramus ------------------------------------------------------- 7 

Family Margaritiferidae-------------------------------------------------------- 7 

Genus Margaritifera ------------------------------------------------------- 7 

Family Unionidae ------------------------------------------------------------- 8 

Genus Unio --------------------------------------------------------------- 8 

Family Laternulidae ----------------------------------------------------------- 8 

Genus Anatimya ---- --- - --- - --- --- --- -- -- -- -- --- --- - - --- - --- --- - ---- - - --- - 8 

Ammonites ----------------------------------------------------------------------- 8 

Family Scaphitidae------------------------------------------------------------ 8 

Genus Scaphites --- - - --- - - - --- - - - --- --- -- ----- -- -- - - --- - ---- - - --- - ----- - - - 8 

Genus Otoscaphites ------------------------------------------------------- 11 

Family Engonoceratidae - - --- ------ --- --- -- - - ---- --- -- -- ---- - - --- - - --- - --- - --- - 11 

Genus Metengonoceras----------------------------------------------------- 11 

Family Placenticeratidae------------------------------------------------------- 11 

Genus Proplacenticeras ---------------------------------------------------- 11 

Family Acanthoceratidae------------------------------------------------ ~------ 12 

Genus Dunveganoceras -------------------------------------------- -------- 12 

Genus Metoicoceras ------------------------------------------------------- 14 

Genus Watinoceras -------------------------------------------------------- 15 

Family Collignoniceratidae ----------------------------------------------------- 16 

Genus Collignoniceras ----------------------------------------------------- 16 

Genus Subprionocyclus ---------------------------------------------------- 18 

Genus Prionocyclus-------------------------------------------------------- 19 

Belemnite ------------------------------------------------------------------------ 20 

Family Belemnitellidae - - - ---- ---- -- -- - - --- - - - --- --- -- --- --- - ---- --- - - --- --- - - - 20 

Genus Actinocamax ------------------------------------------------------- 20 

References cited --- -- - --- - - --- --- ----- - ---- - - --- -- - --- - --- - - --- --- ---- - --- - - --- - - - --- - - 21 

Index - - - -- - -- -- - -- - - -- - - - - - -- - - -- - -- - - -- - - - -- -- - --- - - -- -- - - -- - - - -- -- - -- - - - - -- - -- -- - - - 23 

III 
IV CONTENTS 

ILLUSTRATIONS 

[Plates follow index of chapter A] 

PLATE 1. Turonian mollusks. 

2. Cenomanian and Turonian bivalves. 

3. Inoceramus. 

4. Cenomanian bivalves. 

5. Turonian ammonites. 

6. Dunveganoceras and Metengonoceras. 

7. Proplacenticeras, Metengonoceras, and Actinocamax. 

8. Cenomanian, Turonian, and Coniacian mollusks. 

9-11. Dunveganoceras. 

12. Metoicoceras and Dunveganoceras. 

13. Metoicoceras. 

14. Cenomanian and Turonian mollusks. 

15. Cenomanian, Turonian, and Coniacian mollusks. 

Page 

FIGURE 1. Index map of important fossil.collections---------------------------------------- 2 

2. Whorl section of Dunveganoceras pondi --------------------------------------- 13 

3. Whorl section of Dunveganoceras hagei---------------------------------------- 14 

4. Whorl section of Dunveganoceras hagei ---------------------------------------- 14 

5. Map showing Localities of Actinocamax --------------------------------------- 20 
STRATIGRAPHY AND PALEONTOLOGY OF 

MID-CRETACEOUS ROCKS IN MINNESOTA AND CONTIGUOUS AREAS 

MOLLUSCAN FOSSIL RECORD FROM THE NORTHEASTERN PART 

OF THE UPPER CRETACEOUS SEAWAY, WESTERN INTERIOR 

By WILLIAM A. CoBBAN 

ABSTRACT 

Molluscan fossils are locally abundant at outcrops of Upper 

Cretaceous rocks in eastern North and South Dakota, northeastern 

Nebraska, northwestern Iowa, and western and northern Minnesota. 

Other Cretaceous mollusks have been found in the glacial deposits in 

Minnesota, Iowa, and Illinois. 

The oldest well dated marine mollusks are of earliest late Cenomanian age and occur in northwestern Iowa. Mollusks of marginal marine 

and nonmarine environments in northwestern Iowa and south-central 

Minnesota are probably of slightly younger late Cenomanian age. The 

youngest mollusks treated in this report are bivalves of Santonian age 

found in the Niobrara Formation in eastern North and South Dakota. 

The collections indicate the presence or former presence of the following ammonite zones in the northeastern part of the Western Interior 

seaway: 

Santonian 

Coniacian 

Turonian 

{ Scaphites depressus-Clioscaphites choteauensis 

{ 

Scaphites ventrocosus 

Scaphites preventricosus 

Scaphites corvensis 

Scaphites whitfieldi 

Prionocyclus hyatti 

Subprionocyclus percarinatus 

Collignoniceras woollgari 

Watinoceras coloradoense 

{ 

Dunueganoceras albertense Cenomanian Dunueganoceras pondi 

INTRODUCTION 

Molluscan fossils of Cretaceous age from the east side 

of the Western Interior Cretaceous seaway were first 

described by Hall and Meek ( 1856), who named a new 

bivalve (Pectunculus [Sanoarca] siouxensis) and a new 

ammonite (Ammonites [Subprionocyclus] percarinatus) 

from beds now assigned to the Dakota Sandstone and 

Carlile Shale, respectively. Additional mollusks were 

treated in later reports by Meek and Hayden (1857, 

1860), Meek (1871, 1873, 1876), and White (1894). Much 

later, Bergquist (1944) described a large assemblage of 

Cretaceous mollusks from the Mesabi Range, northern 

Minnesota (fig. 1). Since the completion of Bergquist's 

work, no new systematic papers concerning Cretaceous 

molluscan fossils in the northeastern part of the seaway 

have been published. The mollusks collected by J. N. 

Nicollet, "near the confluence of the Sioux and Missouri 

rivers, in a thick stratum of clay" (Morton, 1842, p. 212), 

are from the Pierre Shale and Fox Hills Formation at 

localities along the Missouri River in central and northcentral South Dakota, northwest of the area of the present report. 

The oldest well dated molluscan fossils in the region 

investigated are from the top of the Dakota Formation 

and basal part of the overlying Graneros Shale at Sioux 

City, Iowa, where Dunueganoceras pondi Haas of earliest 

late Cenomanian age (in terms of a threefold division for 

the Cenomanian) was collected. The youngest molluscan 

fossils are from the Niobrara Formation of eastern North 

and South Dakota, where fragments of Platyceramus 

platinus (Logan) of Santonian age were found. Younger 

mollusks of Campanian age, derived from the Pierre 

Shale, have been found in the glacial drift in Minnesota 

and Iowa, but these are not included in this report. 

With the exception of a new species and a new subspecies, this report is not a detailed systematic treatment of the molluscan faunas, but rather it is a 

generalized guide to the more common and important 

species. In most instances, synonymies include only the 

original report in which a species was named and one or 

two later reports that contain important changes in 

nomenclature or contain good illustrations. 

1 
2 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

94° 93° 92° 91° ·----r·-----,----r---1 

NORTH 

DAKOTA 

Fergus 

Falls 

0 

ONTARIO 

RANGE 

t-J\'C:Sp..S\ Hibbing 0Virginia 

Marble 0 . ~Keewatm 

~ Calumet 

Grand Rapids Coleraine 

MINNESOTA 

Brainerd 

/ 

Duluth/ 

Cf-.; 

r 

I 

I 

----------{ NTwoRiver I' ~ . j/jLake Traverse I 

Stssetono rt'3r S Two River f 

~ 

~ rowns Valley Soli~ Cloud '\ 

A!J WISCONSIN ~Or~onville Richmond ~'SO>.o 1 

Milban~<:~~Odessa vO' 

Dakota>q ~1ano quarry oLitchfield ~ ~ ranite Co I Bellingham Minneapolis a ST ~AUL quarry j Yellow Granite 1 

~- Medicine River: Falls 

I.P I Taunton ~~ 

I 0 Ghent o -'le.s-0 

0 I Marshall o Redwoo~o New I De Smet o 0 Russell Fa~ ~~lm 

1 "2· ~ I Tyler Springfield o Mankato R h t '' 

44or ~ \ II Comfrey o oc es er ~\( 

Mitchell ..-

I S~~U~o l _____ ~w~~ington------------------{ I ~ ~ ~ /) ~ Olivet ~ .._ ~ o Forest City I 

I '""~u-o t; ' I 

43°r '% o/ofHawarden \-

r-::::-: -> ·~~u ton 

1 

'Z Yanktonr. tt .

11 . 

'- StJames~ 'Sf)Westfield 

I Volc~o CLn.I _::*)~Ponca Park 

t.lk P~mt X: ~Riverside 

!

, Ponca s· c· 

Dakota City \ toux Jty 

I 7~ 42o/ N E B R A S K A ~ 

I I ~ 

0 Fort Dodge 

IOWA 

/ Om~ad 

41° L. ____ .L-_ ___ ___t_ ___ __,_I J~ __ _L ___ .___L____ 

100 200 KILOMETERS 

50 100 MILES 

FIGURE 1.-Index map showing study area and localities of important fossil collections (x). 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 3 

ACKNOWLEDGMENTS 

Much of this report could not have been prepared 

without the excellent collections of Cretaceous fossils 

(from the Mesabi Range and from the glacial drift of 

Minnesota) placed at my disposal by Professor R. E. 

Sloan, Department of Geology and Geophysics, University of Minnesota, Minneapolis. Professor F. D. Holland, 

Jr., and Professor A.M. Cvancara, Geology Department, 

University of North Dakota, Grand Forks, provided collections from the Carlile Shale of northeastern North 

Dakota as well as unpublished theses concerning these 

fossils. Professor D. G. Darby, Department of Geology, 

University of Minnesota, Duluth, loaned a very fine 

specimen of Dunveganoceras hagei from the Mesabi 

Range. Professor R. E. Stevenson, Department of Earth 

Science and Physics, University of South Dakota, Vermillion, kindly permitted study of collections from the 

Carlile Shale of southeastern South Dakota. Professor 

Karl M. Waage, Peabody Museum of Natural History, 

Yale University, New Haven, Conn., loaned several ammonites and inoceramids collected by him and his students from the basal part of the Graneros Shale at Sioux 

City, Iowa, and he gave much helpful stratigraphic advice. Professor G. W. Shurr, Department of Physics 

(Earth Sciences), St. Cloud State College, St. Cloud, 

Minn., provided mollusks collected by him and his students from the Greenhorn and Carlile Formations of 

western Minnesota. Doctor A. S. Horowitz, Department 

of Geology, Indiana University, Bloomington, provided 

the large specimens of Inoceramus prefragilis stephensoni illustrated in this report. W. J. Schwarting, Director, Sioux City Public Museum, Sioux City, Iowa, kindly 

loaned the excellent specimens of Dunveganoceras pondi 

and Metengonoceras dumbli figured in this report. 

David Jones,· Jones Fossil Farm, Worthington, Minn., 

drew my attention to a splendid specimen of 

Prionocyclus found in the glacial drift by Timothy D. 

Holt, Marshall, Minn. James Stengel, Dakota Granite 

Company, Milbank, S. Dak., gave permission to collect 

from the company's quarries. 

The photographs in this report and some of the fossil 

collections were made by Robert E. Burkholder, U.S. 

Geological Survey. Illustrated specimens having 

"USNM" catalog numbers are stored in the Museum of 

Natural History in Washington, D.C. 

IMPORTANT MOLLUSCAN FOSSILS 

The fossils treated on the following pages are mostly 

those that closely date the Cretaceous outcrops in the 

region as well as those that indicate the former presence 

of Cretaceous rocks. An exception are two species of ammonites new to the Western Interior. 

Many of the figured specimens are at the Department 

of Geology and Geophysics, University of Minnesota, 

Minneapolis, and have the catalog abbreviations UMIP 

(University of Minnesota Invertebrate Paleontology). 

Other specimens are stored in the National Museum of 

Natural Science, Washington, D.C., and have USNM 

catalog numbers. Specimens at Peabody Museum of 

Natural History, Yale University, have YPM catalog 

numbers, and specimens at the Sioux City Public 

Museum, Sioux City, Iowa, have SCPM numbers. 

Plaster casts of a few of the figured specimens are kept in 

the U.S. Geological Survey's Mesozoic invertebrate collections at the Federal Center, Denver, Colo. Fossils 

from U.S. Geological Survey Mesozoic localities have 

catalog numbers preceded by USGS. 

BIVALVES 

Family INOCERAMIDAE Giebel, 1852 

Genus INOCERAMUS J. Sowerby, 1814 

Inoceramus fragilis Hall and Meek 

Plate 1, figure 2 

1856. Inoceramus fragilis Hall and Meek, American Academy of Arts 

and Sciences Memoirs, n. ser., v. 5, p. 388, pl. 2, figs. 6a, b. 

1952. Inoceramus fragilis Hall and Meek. Stephenson, U.S. Geo-

(1953) logical Survey Professional Paper 242, p. 64, pl. 12, figs. 3, 4. 

The holotype (Am. Mus. Nat. History 9358/1), refigured by Stephenson (1952, pl. 12, figs. 3, 4), is a small 

moderately convex right valve about as long as it is high; 

the hingeline is straight, and the beak is terminal and 

pointed. Ornamentation consists of rugae and evenly 

spaced growth lines. The specimen is on a piece of gray 

shale containing several impressions of the middle Turonian ammonite Subprionocyclus percarinatus (Hall and 

Meek) from "***On the Missouri River, five miles below 

the mouth of Vermilion River. In the lower clay beds of 

division No.2 of section" (Hall and Meek, 1856, p. 388). 

This locality, now known as Volcano Hill (fig. 1), but 

earlier called Ionia Volcano, is a splendid outcrop of 

Carlile Shale (Conqra, 1908, p. 13). 

In the course of mapping the Elk Point 30-minute 

quadrangle (S. Dak.-Nebr.-Iowa), J. E. Todd collected 

a fragment of a very fossiliferous gray limestone concretion from the Carlile Shale southwest of Vermillion on 

the south bank of the Missouri River in sec. 29, T. 32 N., 

R. 4 E., Dixon County, Nebr. (USGS 2989). This fragment (pl. 1, fig. 2) is remarkable in that one side contains many specimens of Inoceramus closely matching 

the holotype of I. fragilis. Like the holotype, the 
4 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

Inoceramus is associated with Subprionocyclus percarinatus. The opposite side of the fragment has parts of 

large specimens of Inoceramus cuvieri J. Sowerby. The 

holotype of I. fragilis and the small specimens in Todd's 

concretion, as well as other small specimens from the 

Carlile Shale of northern Dixon County, could be interpreted as juveniles of I. cuvieri. Adult specimens of I. 

cuvieri that have the beaks and umbonal part preserved 

are lacking in the collections from the Missouri River 

area; consequently, the two species names are retained 

for the present. 

Type.-Hypotype USNM 299138. 

Inoceramus prefragilis stephensoni Kauffman and Powell 

Plate 2, figures 19, 20; plate 3 

1977. Inoceramus prefragilis stephensoni Kauffman and Powell, 

Geological Society of America Memoir 149, p. 62, pl. 2, figs. 

1, 3, 6, 8, 10. 

The types of Inoceramus prefragilis stephensoni 

(USNM 169325-169332) are from the lower part of the 

Lincoln Limestone Member of the Greenhorn Formation 

in the Oklahoma Panhandle. The types of I. prefragilis 

prefragilis Stephenson (USNM 105151-105156) are from 

the Lewisville Member of the Woodbine Formation in 

Grayson County, northern Texas. 

Stephenson (1952, p. 64, pl. 12, figs. 10-12; pl. 13, figs. 

1, 2) characterized I. prefragilis prefragilis .as 

Adult shell large, moderately inflated, higher than long, strongly inequilateral, slightly inequivalve. Beaks terminal, prominent, strongly 

incurved, prosogyrate * * * shell most prominently inflated in the urnbona! region.* * * The posterior slope [of the shell] may or may not 

bear one or two broad, shallow radial depressions.* * * Surface of 

medium-sized specimens ornamented all over, or nearly so, with 

closely spaced low, narrow, concentric ribs and may or may not exhibit 

irregular, broad growth undulations. The narrow concentric markings 

are most sharply and regularly developed in the umbonal region, with a 

tendency to become less regular ventrally; on large individuals the surface away from the umbonal region is almost without the narrow concentric markings, presenting instead coarse, irregular undulations. 

Stephenson's types were associated with a diversified 

assemblage of bivalves and gastropods but no ammonites. Ammonites were not listed by Stephenson from 

the Lewisville Member of the Woodbine Formation in 

Grayson County. However, from the overlying Templeton Mem her of the Woodbine in Grayson County, 

Stephenson (1952, p. 201-210) recorded Acanthoceras 

hazzardi Stephenson, A. cuspidum Stephenson, Mummites? bellsanus Stephenson, M etengonoceras dumbli 

(Cragin), Metoicoceras swallovii (Shumard), M. 

latoventer Stephenson, and M. crassicostae Stephenson. 

Acanthoceras hazzardi Stephenson (1952, p. 201) is a 

synonym of A. amphibolum Morrow (1935, p. 470), and 

Mammites? bellsanus Stephenson (1952, p. 204) may be 

an example of Plesiacanthoceras wyomingense (Reagan, 

1924, p. 181). Accordingly, the types of I. prefragilis 

prefragilis are probably from some zone older than that 

of A. amphibolum. In Kansas A. amphibolum occurs in 

the uppermost part of the Graneros Shale, and in 

Colorado, where the Graneros-Greenhorn contact is 

drawn a little higher, A. amphibolum occurs in the uppermost part of the Graneros Shale and in the basal part 

of the Lincoln Limestone Member of the Greenhorn Formation. 

Inoceramus prefragilis stephensoni differs from I. 

prefragilis prefragilis in having a broader and flatter 

shell without the shallow posteroventral radial sulci and 

in having the regular concentric ornamentation persisting throughout most of the growth. In the Western 

Interior, I. prefragilis stephensoni occurs in the Cenomanian zones of Plesiacanthoceras wyomingense and 

Dunueganoceras pondi. 

Large inoceramids in the Graneros Shale along the 

Missouri River valley in northeastern Nebraska and 

northwestern Iowa are referred to I. prefragilis stephensoni. A slab of siltstone from the Sioux City Brick and 

Tile Company's claypit at Riverside, Iowa, has excellent 

specimens more than 140 mm in height (pl. 3). Other 

localities where the subspecies occurs are in the claypit 

in the NW1

/4SE% sec. 14, T. 89 N., R. 48 W., at Riverside (USGS D10405); west of Dakota City in the 

SW%NW% sec. 20, T. 28 N., R. 8 E., Dakota County, 

Nebr. (USGS D10402); at Ponca State Park in the SE1

/4 

sec. 3, T. 30 N., R. 6 E., Dixon County, Nebr. (USGS 

D10403); and in the SW%NW% sec. 4, T. 90 N., R. 48 

W., Plymouth County, Iowa (USGS D10412). 

Fragments of inoceramids that may be I. prefragilis 

stephensoni were found farther northwest at an excavation southeast of Mitchell in the SE%NE% sec. 8, T. 102 

N., R. 59 W., Hanson County, S.Dak. (USGS D10701). 

Here, bluish-gray clay shale, distorted by glacial action 

and possibly included in the drift, rests on the 

Precambrian Sioux Quartzite. Palynomorphs in the 

shale were reported on by R. H. Tschudy as follows (written commun., July 1979): 

In addition to the marine forms, dinoflagellates, acritarchs, and 

Pterospermopsis, very few palynomorphs of terrestrial origin were present. The following poorly preserved taxa were found: 

Taxodiaceaepollenites 

Araucariacites 

Equisetosporites 

Bisaccate conifer pollen 

Pristinuspollenites 

Tricolpites reticulate, small 

Tetracolpites smooth, small 

Trilete spores-very few 

Schizosporis reticulatus Cookson and Dettmann. 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 5 

'J'he presence of small specimens of Tricolpites and Tetracolpites indicates an age no older than middle Albian. The presence of 

Schizosporis reticulatus Cookson and Dettmann indicates an age no 

younger than Cenomanian. This species has not been found in rocks 

younger than Cenomanian nor older than Berriasian anywhere in the 

world. 

Types.-Hypotypes USNM 299147; YPM 14895, 

14896. 

Inoceramus ginterensis Pergament 

Plate 2, figures 17, 18 

1966. Inoceramus ginterensis Pergament, Transactions of the 

Geological Institute of the Academy of Sciences of USSR, v. 

146, p. 50, pl. 25, fig. 5; pl. 26, figs. 1, 2; pl. 27, figs. 1, 2; pl. 

28, figs. 1, 2; pl. 29, fig. 1. 

1977. Inoceramus ginterensis Pergament. Kauffman and Powell, 

Geological Society of America Memoir 149, p. 64, pl. 1, fig. 

2; pl. 3, figs. 1-4, 6; pl. 4, figs. 1, 3-6; pl. 5, figs. 2, 3, 5; pl. 7, 

fig. 4. 

This species resembles Inoceramus prefragilis 

Stephenson in size, outline, and convexity. The ornamentation, however, differs considerably; I. ginterensis has rugae of irregular strength and spacing, and 

the urn bonal area may be bounded by a concentric 

sulcus. Evenly spaced growth lines may or may not be 

present on the umbonal area. 

Inoceramus ginterensis was originally described from 

Cenomanian rocks in northwestern Kamchatka and 

southern Sakhalin, U.S.S.R. (Pergament, 1966). The 

species is widely distributed in the Western Interior in 

the late Cenomanian zone of Dunueganoceras albertense 

(Warren). 

Septarian limestone concretions in the upper part of 

the Graneros Shale along the Missouri River valley in 

northwestern Iowa contain I. ginterensis (USGS 

D10503). These specimens closely resemble those illustrated by Pergament (1966, pls. 25-29). 

Types.-Hypotypes USNM 299145, 299146. 

Inoceramus mesabiensis Bergquist 

Plate 2, figures 7, 8, 11, 12 

1944. Inoceramus fragilis mesabiensis Bergquist, Journal of Paleontology, v. 18, no. 1, p. 12, pl. 5, figs. 3-6, 8. 

This moderately small inequivalved late Cenomanian 

inoceramid is characterized by its great convexity, subrectangular outline, height greater than length, steep 

anterior and posterior edges, and prominent beaks 

curved inward and anteriorly. The hinge line is straight 

and set at a high angle to the rest of the shell. Ornamentation consists of inconspicuous growth lines and more 

prominent rugae of irregular spacing and height:. 

Bergquist's types (UMIP 5019, 5019a-c) came from 

ferruginous conglomerate in the basal part of the 

Coleraine Formation at the Hill Annex mine in the 

Mesabi Range at Calumet, Minn. Ammonites from the 

bed of conglomerate at this mine were described by 

Bergquist (1944, p. 29, 30) as Metoicoceras aff. M. swalloui (Shumard) [M. bergquisti Cobban, n. sp.], 

Epengonoceras [Metengonoceras] cf. E. dumbli 

(Cragin), and Metacalycoceras? sp. and Acanthoceras 

sp. [both Dunueganoceras hagei Warren and Stelck]. 

Well-preserved internal molds of dark-brown, very fine 

grained ferruginous sandstone occurred in the Coleraine 

Formation in the Bennett open-pit iron mine at 

Keewatin, Minn. (USGS 13766), and two of these 

specimens are shown on plate 2, figures 7, 8, 11, 12. 

Typical specimens of I. mesabiensis have not been 

found in the Western Interior outside the Mesabi Range. 

A closely related smaller and less convex subspecies occurs in the zone of Dunueganoceras albertense (Warren) 

in the Frontier Formation along the west and south 

flanks of the Powder River Basin in Wyoming and in the 

Hartland Shale Member of the Greenhorn Formation 

along the east side of the basin. Similar specimens occur 

in the zone of Dunueganocercis albertense as far north as 

north-central Montana (Cobban and others, 1976, p. 39). 

Types.-Hypotypes USNM 299143, 299144. 

Inoceramus apicalis Woods 

Plate 2, figures 1-6, 9, 10; plate 8, figure 10 

1912. Inoceramus lamarcki var. apicalis Woods, Palaeontographical 

Society Monograph, v. 65, p. 319, pl. 53, figs. 4-6. 

Inoceramus apicalis Woods is a moderately small inequivalved species that is very inequilateral, narrow, 

much inflated, and ornamented by regular concentric 

growth· lines and (or) lamellae with occasional rugae. 

The hingeline is straight and long and forms a very high 

angle with the rest of the shell. The posterior auricle, 

which is well developed and subtriangular, is separated 

from the rest of the shell by a marked change in the 

postumbonal slope. 

The types of I. apicalis came from the upper part of 

the Middle Chalk of England (upper Turonian). 

Specimens that seem assignable to I. apicalis occur with 

Collignoniceras woollgari regulare (Haas) in the silty 

limestone resting on Precambrian granite in the Dakota 

Granite Company's quarry (fig. 1) east of Milbank, S. 

Dak. (USGS D10415, SW1/4 sec. 18, T. 120 N., R. 47 W., 

Grant County). Specimens also occur with Subprionocyclus percarinatus (Hall and Meek) in limestone 

concretions in the Carlile Shale at Volcano Hill (USGS 

D10404) in sec. 3, T. 31 N., R. 5 E., Dixon County, Nebr. 

Types.-Hypotypes USNM 299139-299142, 299178. 
6 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

1876. 

1879. 

Inoceramus howelli White 

Plate 2, figures 13-16 

Inoceramus howelli White. Powell; U.S. Geological and 

Geographical Survey of the Territories, p. 114. 

Inoceramus howelli White. White, U.S. Geological and 

Geographical Survey of the Territories, 11th Annual Report, 

p. 284, pl. 4, fig. la-c. 

1893. Inoceramus fragilis Hall and Meek (part). Stanton, U.S. Geo-

(1894) logical Survey Bulletin 106, p. 76, pl. 11, figs. 3-5 only. 

This moderate-sized inequivalved species is easily 

recognized by its prominent posteroventral fold bounded 

by well-defined sulci. The shell is moderately convex, 

and its height is greater than its length. The hingeline is 

straight and conspicuous. Ornamentation consists of low 

rugae of irregular strength and spacing. 

Inoceramus howelli is an important guide fossil to the 

middle Turonian zone of Prionocyclus hyatti (Stanton). 

White's types came from the lower sandstone member of 

the Straight Cliffs Formation (Peterson and Waldrop, 

1965, fig. 3) in the Lower Potato Valley west of Escalante 

in southern Utah. The species is widely distributed in 

the Western Interior. 

Many well-preserved specimens of Inoceramus howelli 

were found in a large boulder of very fine grained ferruginous sandstone in the glacial drift across the street 

from the Yellow Medicine County Museum in Granite 

Falls, Minn. The specimens very closely resemble 

White's types in size, form, and ornamentation. Most of 

the boulder is on display at the County Museum, but 

good specimens from it are in the collections of the 

University of Minnesota, Minneapolis. 

Types.-Hypotypes UMIP 9000a, 9000b. 

Inoceramus cuvieri J. Sowerby 

1822. Inoceramus cuvieri J. Sowerby, Transactions of the Linnean 

Society of London, v. 13, p. 453, pl. 25. 

The lectotype of the Turonian Inoceramus cuvieri J. 

Sowerby, refigured by Woods (1912, text fig. 73), is a left 

valve about 113 mm high that is characterized by its 

suberect form, a height greater than its length, fairly low 

convexity, and ornamentation of evenly to subevenly 

spaced lamellae and a few low rugae. The specimen is 

from the Middle Chalk of England. 

Fragments of large inoceramids that have low convexity and fairly evenly spaced flat lamellae occur in the 

Carlile Shale in northeastern Nebraska (USGS 2984, 

2989, D10404). These fragments are interpreted as pieces 

of large individuals of I. cuvieri. Hattin (1962, pls. 15, 21) 

noted similar-sized flattened specimens of I. cumen 1n 

the Carlile Shale of Kansas. 

Genus MYTILOIDES Brongniart, 1822 

Mytiloiqes mytiloides (Mantell) s.l. 

Plate 1, figure 1; plate 8, figures 8, 9 

1822. Inoceramus mytiloides Mantell, the fossils of the South Downs, 

or illustrations of the geology of Sussex: London, Lupton 

Relfe, p. 215, pl. 28, fig. 2. 

For synonymy and other illustrations, see Kauffman and Powell, 1977, 

Geological Society of America Mem. 149, p. 74, 76. 

This thin-shelled species is characterized by its 

elongate form, low convexity, conspicuous posterior auricle, and distinctive ornamentation, usually consisting of 

more or less evenly spaced rugae and raised growth lines 

on the rugae as well as in the space between rugae. The 

hingeline is straight, and the shell axis is strongly inclined to it. Mytiloides mytiloides is the species usually 

referred to as Inoceramus labiatus (Schlotheim) in 

Cretaceous literature, although the latter species does 

occur (pl. 8, fig. 7). In the Western Interior, M. 

mytiloides occurs in vast numbers in the upper part of 

the Bridge Creek Limestone Member of the Greenhorn 

Formation. At Pueblo, Colo., the species is especially 

abundant and well preserved in bed 113 of Cobban and 

Scott (1972, pl. 41) where it is associated with Mammites nodosoides (Schlotheim), Choffaticeras pavillieri 

(Pervinquiere), and other ammonites of late early Turonian age. 

Specimens referable to Mytiloides mytiloides s. l. are 

abundant in thin beds of limestone in the Greenhorn 

Formation along the Missouri River in northeastern 

Nebraska and northwestern Iowa, as well as in scattered 

outcrops in southeastern South Dakota and southwestern Minnesota. The valves occur separated, and 

most are in the 60-120 mm range in length (pl. 1, fig. 1). 

Along the Missouri River (USGS D10406, D10502) and 

along the lower reaches of the Big Sioux River (USGS 

D10413), M. mytiloides occurs in a bluff-forming sequence of thin beds of hard limestone and softer chalk 

and calcareous shale that could be referred to the Bridge 

Creek Limestone Member of the Greenhorn Formation. 

Mollusks, other than M. mytiloides, are extremely 

sparse in these beds. Similar Bridge Creek like beds, 

that contain abundant M. mytiloides, are well exposed 

along Brule Creek in the SW1

/4SW1/4 sec. 7 and 

NE%NW% sec. 18, T. 92 N., R. 49 W., Union County, 

S. Dak. (USGS D10703, D10411). At the western boundary of Minnesota, Bridge Creek like beds containing M. 

mytiloides crop out on the shore of Lake Traverse 

(Shurr, 1979, USGS D10372). Farther southeast, in 

the Ortonville-Bellingham area of Minnesota, M. 

mytiloides is abundant in hard thin beds of limestone of 

Bridge Creek lithology that rest on Precambrian granite 

(USGS D10373, D10706). The fossil recorded as 

Inoceramus barabina Morton by Sloan (1964, p. 15) from 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 7 

one of the granite quarries is probably M. mytiloides, unless it represents a specimen derived from the Pierre 

Shale in the glacial drift. At this quarry, south of 

Odessa, Minn., in the NEV4SE 1/4 sec. 32, T. 121 N., R. 

45 W. (USGS D10373), thin beds of limestone resting on 

the granite contain abundant pelagic foraminifers, barnacle plates, fish scales, bones, and teeth, as well as M. 

inytiloides, Ostrea sp., and a brachiopod identified by J. 

T. Dutro, Jr., as probably a new species of Discinisca 

(Discradisca). A fissure filling of hard, sandy limestone 

in the granite at the Delano quarry, a few kilometers to 

the southeast in the SE 1;4 SE 1;4 sec. 16, T. 120 N ., R. 45 

W. (USGS D10420), contains fragments of M. mytiloides 

associated with Amphidonte? sp., Discinisca 

(Discradisca) sp., fish scales and bones, and shark teeth. 

Type.-Hypotype USNM 299137. 

Genus PLATYCERAMUS Heinz, 1932 

Platyceramus platinus (Logan) 

1898. Inoceramus platinus Logan, Kansas University Geological 

Survey, v. 4, pt. 8, p. 491 [not pl. 116]. 

1964. Inoceramus platinus Logan. Scott and Cobban, U.S. Geological 

Survey Professional Paper 454-L, pl. 9. 

This inoceramid is very large, flat, about as long as it 

is high, and ornamented by concentric rugae of irregular 

height and spacing. The hingeline is straight and long, 

and the beak is located at its anterior end. A very large 

size is attained by this species; a magnificent specimen 

on display in the Fort Hays State College Museum, 

Hays, Kans., is about a meter in height (Moore, 1958, 

fig. 16.19; Miller, 1968, pl. 3, fig. 1). 

Platyceramus platinus is abundant in the Niobrara 

Formation in the Great Plains region. Fragments, 

encrusted by the oyster Pseudoperna congesta (Conrad), 

occur on Niobrara outcrops in eastern North Dakota, 

southeastern South Dakota, and northeastern Nebraska. 

The species may range throughout the Santonian (Scott 

and Cobban, 1964, p. L5). 

Genus VOLVICERAMUS Stoliczka, 1871 

Volviceramus involutus (J. de C. Sowerby) 

Plate 15, figures 13, 14 

1828. Inoceramus involutus J. de C. Sowerby, The .mineral conchology of Great Britain, v. 6, p. 160, pl. 583, figs. 1-3. 

1871. Inoceramus (Volviceramus) involutus Sowerby. Stoliczka, The 

Cretaceous fauna of southern India, v. 3, The Pelecypoda, 

India Geological Survey Memoirs, Paleontologia Indica, p. 

394, 401. 

Voluiceramus inuolutus is a moderate-sized species 

that is very inequilateral and extremely inequivalve. The 

left valve is much larger than the right one, very inflated, 

spirally coiled, and nearly smooth. The right valve has a 

nearly oval outline and a very low convexity; it is ornamented by conspicuous concentric rugae. 

The holotype of V. inuolutus is from the Upper Chalk 

of England. Specimens that seem referable to this 

species occur in the lower part of the Smoky Hill Shale 

Member of the Niobrara Formation in southeastern 

Colorado (Scott and Cobban, 1964, p. L5, L9-L13) and 

in the equivalent part of the Niobrara Formation in the 

central Great Plains as well as in age-equivalent rocks in 

north-central Montana (Cobban, 1955, p. 204, pl. 2, figs. 

6-9; Cobban and others, 1976, p. 59). The species is most 

abundant in the late Coniacian zone of Scaphites 

uentricosus Meek and Hayden. 

Voluiceramus inuolutus was recorded by Hattin (1975, 

p. 205, pl. 3, fig. 7) as V grandis (Conrad), from chalky 

limestone 1.5-2.7 m above the base of the Niobrara Formation, north of St. James in northeastern Nebraska 

(NW 114 sec. 7, T. 32 N., R. 3 E.). Specimens occur in the 

same part of the Niobrara Formation about 12 km 

farther northwest (pl. 15, figs. 13, 14). Outcrops of the 

Niobrara Formation far to the north, in northeastern 

North Dakota, also contain V. inuolutus (USGS D10419, 

NW1/4 sec. 34, T. 163 N., R. 57 W., Cavalier County). 

Type.-Hypotype USNM 299191. 

Family MARGARITIFERIDAE Haas, 1940 

Genus MARGARITIFERA Schumacker, 1816 

Margaritifera cf. M. nebrascensis (Meek) 

Plate 4, figures 6-8 

Two large well-preserved clams from the Cenomanian 

Dakota Formation at the mouth of Two River in sec. 8, 

T. 127 N., R. 29 W., Morrison County, Minn. (fig. 1), 

may represent Margaritifera nebrascensis (Meek). This 

species was originally described as Unio (Baphia?) 

nebrascensis Meek (1871, p. 303). No illustrations were 

given. Later Meek (1876, p. 114, pl. 1, fig. 5a-c) illustrated it and assigned it to Margaritana. Much later, 

Henderson (1935, p. 68) placed it more correctly in 

Margaritifera. 

Meek's species was originally based on two specimens, 

a large inflated one, regarded as the holotype by White 

(1883, p. 427), and a much smaller internal mold. These 

specimens, the only ones figured for the species, came 

from the Dakota Formation near Dakota City, Nebr. The 

holotype is characterized by its elongate rhomboid outline, inflated shell, prominent beaks situated near the 

anterior end, sinuous ventral margin, and a conspicuous 

ridge that extends from the urn bo to the posteroventral 

margin paralleled by a much weaker fold. The specimens 

from Two River, first noted by Upham (1888, p. 602), are 

more inflated than the holotype and lack the second 

(lower) umbonal-posteroventral fold. These differences 
8 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

may just be intraspecific variations. The specimens also 

show considerable resemblance to Ambonicardia cookii 

Whitfield (1885, p. 25, pl. 11, figs. 11-14) from the 

Raritan Formation of New Jersey. 

The specimens from Two River are limonitic and 

probably came from a ferruginous bed or from clay ironstone concretions in a bed of gray clay. Only 1 or 2 m of 

the Dakota Formation are exposed (Stauffer and Thiel, 

1941, p. 175). 

The specimens are in the collections of the Department of Geology and Geophysics, University of Minnesota, Minneapolis. 

Figured specimen.-UMIP 4567. 

Family UNIONIDAE Fleming, 1828 

Genus UNIO Philipsson, 1788 

Unio barbouri White 

Plate 4, figures 1-4 

1894. Unio barbouri White, U.S. National Museum Proceedings, v. 

17, no. 995, p. 133, pl. 8, figs. 1-3. 

This bivalve, originally described from the Cenomanian Dakota Formation near Fairbury, Nebr., has an 

elongate outline, beaks located near the anterior end, 

and a nearly smooth shell. Several specimens, from 

Cretaceous rocks at the mouth of Two River in sec. 8, T. 

127 N., R. 29 W., Morrison County, Minn., are in the collections of the Department of Geology and Geophysics, 

University of Minnesota, Minneapolis (Stauffer and 

Thiel, 1941, p. 101). The specimens have the same ferruginous preservation as that of the individuals of 

Margaritifera cf. M. nebrascensis and were probably 

found with them. 

Types.-Hypotypes UMIP 4566a, 4566b. 

Family LATERNULIDAE Hedley, 1918 

Genus ANATIMYA Conrad, 1860 

Anatimya plicate Bergquist 

Plate 4, figure 5 

1944. Anatimya plicata Bergquist, Journal of Paleontology, v. 18, no. 

1, p. 21, pl. 1, figs. 1, 2, 5. 

The types came from a conglomerate in the Coleraine 

Formation at the Arcturus iron mine in Marble, Minn. 

The species is large for the genus and differs from the 

type of the genus, Anatimya anteradiata Conrad (1860, 

p. 276, pl. 46, fig. 3), in having a subovate to subelliptical 

outline instead of a rectangular one. 

A single specimen was found in the Cretaceous rocks 

in the Ochs Brick and Tile Company's claypit near 

Springfield in the NE% sec. 26, T. 109 N., R. 35 W., 

Brown County, Minn. Although the specimen is distorted, it shows enough features to assign it to Bergquist's species. The specimen retained its nacreous shell, 

which overlies a ferruginous clay siltstone filling. The 

presence of A. plicata in the Ochs claypit is of considerable interest in that it indicates marginal marine 

conditions in this part of Minnesota in late Cenomanian 

time. The specimen is in the collections of the Department of Geology and Geophysics, University of Minnesota, Minneapolis. 

'/Ype.-Hypotype UMIP 9001. 

AMMONITES 

Family SCAPHITIDAE Meek, 1876 

Genus SCAPHITES Parkinson, 1811 

Scaphites delicatulus sloani Cobban, n. subsp. 

Plate 5, figures 12-15, 18-23 

Scaphites delicatulus Warren (1930a, p. 66, pl. 3, fig. 

3, pl. 4, figs. 7, 8; 194 7, p. 123, pl. 29, fig. 5) is a stout, 

moderately sized scaphite that has fairly abundant, uniformly spaced primary and secondary ribs and a row of 

nodate ventrolateral tubercles. The cotypes came from 

the Smoky River Shale in the Peace River area of 

Alberta, Canada, and the specimen later illustrated by 

Warren came from the Mackenzie River area farther 

north. Several well-preserved adults from the Seabee 

Formation on the north slope of Alaska were illustrated 

by Cobban and Gryc (1961, pl. 37, figs. ·16-24; text fig. 

2a, b, o). Rib counts on the last complete whorl of six 

adult specimens from the Seabee Formation gave a 

range of from 18 to 25 primaries and from 71 to 87 secondaries (Cobban and Gryc, 1961, table 2). 

Scaphites delicatulus sloani, n. subsp., differs from 

the typical form of the species in having more ribs and 

weaker tubercles, as well as in having or tending to have 

a smooth area on the body chamber that separates the 

primary ribs from the row of ventrolateral tubercles. The 

holotype is an internal mold on an adult that has a 

height of 36 mm and a thickness of 18.5 mm. Ten closely 

spaced primary ribs are present on the body chamber. 

On the older half of the body chamber, the primary ribs 

begin at the umbilical shoulder and curve forward on 

crossing the inner part of the flank. Most ribs disappear 

before reaching the row of ventrolateral tubercles. These 

tubercles are small, low, and rounded; they are strongest 

near the base of the body chamber and weaken and disappear near the middle. Two or three secondary ribs 

begin at each tubercle, and each group is separated by 

three or four other secondaries. A total of 63 secondary 

ribs is present on the body chamber. The visible part of 

the last septate whorl has 12 primary ribs and 42 secondaries. The secondary ribs trend straight across the 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 9 

venter on most of the body chamber, but on the oldest 

part, as well as on the outer septate whorl, the ribs bend 

backward a little where they cross the venter. 

The holotype of S. delicatulus sloani came from the 

hard concretionary limestone overlying Precambrian 

granite at the Dakota Granite Company's quarry east of 

Milbank, in the SW% sec. 18, T.120 N., R. 47 W., Grant 

County, S. Dak. (USGS D10415). Twelve specimens, 

mostly phragmocones, were available for study. The 

phragmocones have simple sutures much like that of the 

type of S. delicatulus (Warren, 1930a, pl. 3, fig. 3). 

Scaphites delicatulus ranges from the latest Cenomanian to the middle Turonian. The oldest form, S. 

delicatulus greenhornensis Cobban (1951, p. 18, pl. 1, 

figs. 1-3), occurs in the Sciponoceras gracile Range Zone. 

The typical form of the species seems to be confined to 

the early Turonian; whereas, the subspecies sloani is associated with Collignoniceras woollgari regulare (Haas) 

of middle Turonian age. 

Types.-Holotype USNM 299155, paratypes USNM 

299156-299158. 

Scaphites patulus Cobban 

Plate 1, figure 2 (part) 

1951. Scaphites patulus Cobban, U.S. Geological Survey Professional 

(1952) Paper 239, p. 20, pl. 1, figs. 23-32. 

A depressed body chamber whorl, sparse ribbing, and 

a row of nodes characterize this species. The type lot is 

from limestone concretions in the lower part of the 

Carlile Shale on the east flank of the Black Hills in 

western South Dakota. These specimens have, on the 

adult body chamber, 5-8 primary ribs terminating in 

nodes or bullae and 21-27 secondary ribs. Recently, some 

excellent specimens, associated with Subprionocyclus 

percarinatus (Hall and Meek), were found in the Carlile 

Shale on the south side of the Black Hills by Neal L. 

Larsen, Black Hills Institute of Geological Research, Hill 

City, S. Dak. These included adults as much as 40 mm 

in length. 

A small adult (pl. 1, fig. 2) is present in the limestone 

concretion from the Carlile Shale collected by J. E. Todd 

near the old Vermilion ferry crossing in sec. 29, T. 32 N ., 

R. 4 E., Dixon County, Nebr. (USGS 2989). The body 

chamber is complete, but much of the phragmocone has 

been eroded. Five primary ribs and 20 secondaries are 

present on the body chamber. Associated fossils include 

Subprionocyclus percarinatus, Inoceramus fragilis, I. 

cuuieri, and large fish scales; all are of middle Turonian 

age. 

Type.-Hypotype USNM 299138. 

Scaphites corvensis Cobban 

Plate 5, figures 24, 25 

1951. Scaphites corvensis Cobban, U.S. Geological Survey Profes-

(1952) sional Paper 239, p. 26, pl. 7, figs. 6-10. 

A very well preserved nacreous-shelled adult scaphite 

was found in a clay ironstone concretion in a Minnesota 

Department of Conservation's water well, about 7 km 

north of Russell in Camden State Park (NE 114 SE 1/4 sec. 

32, T. 111 N., R. 42 W., Lyon County). This specimen, 

nearly 60 mm in length, has 10 primary ribs and 40 

secondary (ventral) ribs on the body chamber. Anumbilical swelling is present at the base of the body 

chamber, which, together with the inflated form of the 

shell, suggests a female (Cobban, 1969, p. 7). 

The holotype of S. coruensis, which came from the 

Carlile Mem her of the Cody Shale in Bighorn County, 

Mont., is about the same size as the Minnesota specimen 

but is more slender. Primary ribs on the body chamber 

number 15 and the secondaries number 52. Specimens 

from the Frontier Formation of Wyoming reveal a considerable range in form and size of the shell and in the 

number of ribs on the body chamber. Some Wyoming individuals are as stout as the Minnesota specimen. 

Scaphites coruensis is a transitional form between S. 

nigricollensis Cobban of late Turonian age and S. 

preuentricosus Cobban of early Coniacian age. Scaphites coruensis is ordinarily found with Prionocyclus 

quadratus Cobban, which identifies the youngest of 

several zones of Prionocyclus and is of latest Turonian 

age. However, S. coruensis has been found recently with 

Forresteria (Texasia) cf. F. (T.) dentatocarinatum 

(Roemer) of a post-Prionocyclus, very early Coniacian 

age. This late form of S. coruensis was found in the uppermost part of the Frontier Formation in Fremont 

County, Wyo. Associated fossils include Inoceramus 

frechi Flegel, which has been recorded from both upper 

Turonian and Coniacian rocks in Europe. 

The Minnesota specimen is either from Cretaceous 

shale or from the overlying glacial drift. The specimen 

was said to have come from some depth "between 164 

and 230 feet" (50-70 m). Inasmuch as the surface elevation of the borehole was reported as 1,387 ft (423 m), and 

the contact of the glacial drift with the Cretaceous shale 

was given as 1,219 ft (372m) (Rodis, 1963, fig. 5), the interval164-230 ft includes the basal part of the drift and 

more than 18 m of Cretaceous shale. The drill hole had a 

9-in. diameter (23 em) (Rodis, 1961, table 2), and 

presumably the small concretion (103 mm in length) 

containing the scaphite fell into the bailer. The concretion is unweathered and lacks abrasions; if it came from 

the drift, it was derived from nearby Cretaceous shale. 

The shale in the borehole may represent the uppermost 
10 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

part of the Carlile Shale. Rodis (1963, p. N15, fig. 5) 

recorded thick-bedded limestone beneath the glacial 

drift in an area beginning about 7 km northwest of the 

borehole. This limestone, which I interpret as a remnant 

of the basal part of the Niobrara Formation, lies at elevations between 378 and 384 m (Rodis, 1963, p. N15). 

Inasmuch as the Cretaceous rocks are flat lying in Lyon 

County, the contact of the Cretaceous shale with the 

glacial drift in the borehole should be within 6 m of the 

base of the projected Niobrara Formation. If no significant hiatus occurs at the base of the Niobrara, the shale 

in the borehole may represent some upper part of the 

Carlile Shale, such as an equivalent of the Sage Breaks 

Member of the Carlile on the northeast flank of the 

Black Hills. Such a Sage Breaks age (latest Turonian) 

would fit the identification of the scaphite. However, 

Bolin (1956, p. 282) recorded Niobrara foraminiferids 

from an outcrop 17 km north of the borehole (sec. 7, T. 

113 N., R. 42 W., Lyon County), which should be at a 

lower stratigraphic position than that of the scaphite. 

Yellow, very fine grained, calcareous sandstone crops out 

along the South Branch of Yellow Medicine River in the 

NW 1/4 sec. 7 at an elevation between 338 and 341 m. 

However, Winchell (1874, p. 189) mentioned an outcrop 

of yellowish-weathering, blue clay "at least ten or fifteen 

feet" thick "up a little creek that comes into the Yellow 

Medicine river from the south." The presence of 

Niobrara foraminiferids in one of these outcrops can be 

explained if the scaphite represents the early Coniacian 

form of S. coruensis. Furthermore, it is noteworthy that 

nacreous scaphites, assignable to S. coruensis and S. 

mariasensis Cobban, were found in clay ironstone concretions in the Carlile Shale at one locality along the 

Pembina River in northeastern North Dakota. These 

specimens, now in the Geology Department, University 

of North Dakota, Grand Forks, were collected by W osick 

( 1977), who recorded them as S. carlilensis Morrow in his 

thesis and gave their stratigraphic position as about 40 

m below the top of the Carlile Shale. __ 

The Minnesota specimen is in the Department of 

Geology and Geophysics, University of Minnesota, Minneapolis. The specimen was originally referred to S. 

impendicostatus Cobban of early Coniacian age (Sloan, 

1964, p. 27). 

Type.-Hypotype UMIP 8284. 

Scaphites mariasensis Cobban 

1951. Scaphites mariasensis Cobban, U.S. Geological Survey Profes-

(1952) sional Paper 239, p. 28, pl. 8, figs. 14-17. 

This species occurs in two forms, a large inflated form 

and a small slender one. The large one was described as 

the typical form, and the small one was given the name 

S. mariasensis var. gracillistriatus Cobban (1951, p. 28, 

pl. 8, figs. 7-13). According to present-day systematics, 

the large inflated form would be interpreted as a female, 

and the other, a male (Cobban, 1969, p. 7-13). 

Scaphites mariasensis is characterized by high, narrow, sharp ribs. Primary ribs are abundant and flexuous 

on the body chamber, where they number 15 on the 

holotype. The type came from the basal part of the 

Kevin Member of the Marias River Shale in northcentral Montana, where it was associated with S. 

preuentricosus Cobban, Inoceramus waltersdorfensis 

Andert, and I. erectus Meek, of early Coniacian age. 

Most of an adult scaphite that very closely resembles 

the holotype of S. mariasensis was discovered by Wosick 

(1977) in a unit of clay ironstone concretions in the 

Carlile Shale on the Pembina River. The locality is 5.8 

km east-northeast of Vang, Cavalier County, N. Dak. 

Other fossils from this site include scaphites referable to 

S. coruensis Cobban. These specimens are at the 

Geology Department, University of North Dakota, 

Grand Forks. 

Scaphites preventricosus Cobban 

Plate 8, figures 11-13 

1951. Scaphites preventricosus Cobban, U.S. Geological Survey 

(1952) Professional Paper 239, p. 26, pl. 9, figs. 1-16. 

Like Scaphites mariasensis Cobban, S. preuentricosus 

consists of a large inflated form (female) and a smaller 

and more slender form (male) that was described asS. 

preuentricosus var. sweetgrassensis Cobban (1951, p. 27, 

pl. 10, figs. 18-25). The holotype (female) of the species 

is a complete adult 75 mm long and 39.5 mm thick with 

10 primary ribs and 45 secondary ones on the body 

chamber. The species differs from S. mariasensis in having lower ribs and, on the body chamber, fewer 

primaries. 

The holotype of S. preuentricosus came from the lower 

part of the Kevin Member of the Marias River Shale in 

north-central Montana (early Coniacian age). Associated fossils include S. impendicostatus Cobban, 

Baculites mariasensis Cobban, and Cremnoceramus 

deformis (Meek). 

An excellent specimen of S. preuentricosus was found 

in glacial drift on a farm 1.6 km north of Ghent, Lyon 

County, Minn. The preservation indicates that the 

specimen came from a septarian limestone concretion. 

This scaphite, which closely resembles the holotype of S. 

preuentricosus, is 84 mm long, 43 mm thick, and has 9 

primary ribs and 43 secondary ones on the body 

chamber. The specimen was presented by Phyllis 

Regnier to the Department of Geology and Geophysics, 

University of Minnesota, Minneapolis. 

Type.-Hypotype UMIP 9007. 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 11 

Genus OTOSCAPHITES Wright, 1953 

Otoscaphites seabeensis Cobban and Gryc 

Plate 5, figures 6-11, 16, 17 

1961. Otoscaphites seabeensis Cobban and Gryc, Journal of 

Paleontology, v. 35, no. 1, p. 184, pl. 38, figs. 13-27; text fig. 

2d, e, n. 

Small size, depressed section of body chamber, very 

broad venter, and angular tuberculate ventrolateral 

shoulder are important features of this species. The 

holotype and paratypes are from the Seabee Formation 

at outcrops on the north slope of Alaska. 

Several scaphites, referable to Otoscaphites seabeensis, were collected from a hard concretionary 

limestone that rests on Pre cam brian granite in the 

Dakota Granite Company's quarry east of Milbank, in 

the SW% sec. 18, T. 120 N., R. 47 W., Grant County, S. 

Dak. (USGS D10415). Some individuals (pl. 5, figs. 

9-11) have rib densities comparable to those listed by 

Cobban and Gryc (1961, table 3), but others are either 

more finely ribbed (pl. 5, figs. 16, 17) or more coarsely 

ribbed (pl. 5, figs. 6-8). 

The specimens from near Milbank were associated 

with Scaphites delicatulus sloani and other mollusks 

from the subzone of Collignoniceras woollgari regulare 

(middle Turonian age). 

Types.-Hypotypes USNM 299151-299154. 

Family ENGONOCERATIDAE Hyatt, 1900 

Genus METENGONOCERAS Hyatt, 1903 

Metengonoceras dumbli (Cragin) 

Plate 6; plate 7, figure 8; plate 8, figures 5, 6 

1893. Sphenodiscus dumbli Cragin, Geological Survey of Texas 4th 

Ann. Rept., p. 243, pl. 44, fig. 6. 

For synonymy, see Cobban and Scott, 1972, U.S. Geological Survey 

Professional Paper 645, p. 59. 

This very involute, compressed species has a smooth 

shell except for sinuous growth lines. The venter is very 

narrowly truncated almost to the aperture of large 

adults, where the venter becomes narrowly rounded. · 

Very closely spaced septa are characteristic (pl. 7, fig. 8). 

Lobes are abundant, short, and little divided; saddles 

are broad, shallow, and usually undivided. 

Cragin's types came from the Eagle Ford Shale of 

Texas. The suture of only one specimen was illustrated 

(Cragin, 1893, pl. 44, fig. 6). According to Stephenson 

(1952, p. 207), only one of Cragin's types has been 

located. Stephenson (1952, pl. 55) illustrated this 

specimen as well as a large adult from the Templeton 

Member of the Woodbine Formation of northern Texas. 

At several localities in Texas, Metengonoceras dumbli 

was associated with ammonites identified by 

Stephenson as Acanthoceras tarrantense (Adkins), A. 

tarrantense nitidum Stephenson, A. wintoni Adkins, 

and A. adkinsi Stephenson, all of middle Cenomanian 

age. Inasmuch as the Eagle Ford specimens are from the 

"Metoicoceras whitei zone" (Stephenson, 1952, p. 207) 

at the top of the Cenomanian, Metengonoceras dumbli 

has a considerable range. 

A fragment of M. dumbli from the Mesabi Range was 

first identified as Placenticeras (Sphenodiscus) sp. undet. by C. A. White (in Winchell, 1893, p. 221). Later, 

Bergquist (1944, p. 8, 30) suggested that this fossil was 

Epengonoceras cf. dumb lei (sic), and reported that small 

fragments of it occurred in the Coleraine Formation at 

Calumet and Coleraine, Minn. Specimens of M. dumbli 

from the Mesabi Range are few and fragmentary. The 

largest fragment available is part of an adult body 

chamber, preserved as iron carbonate, which has a whorl 

height of 94 mm. This specimen was presented to the 

late James P. Conlin, Fort Worth, Texas, by Blaine 

Conley, Swan River, Minn. Another of Conley's 

specimens shows the characteristic simple suture and is 

illustrated on plate 8, figures 5 and 6. 

Metengonoceras dumbli has been collected from the 

basal part of the Graneros Shale at Riverside, Iowa, and 

from the Coleraine Formation in the western part of the 

Mesabi Range in northern Minnesota (USGS 13063). 

The better specimens are from the claypits at Riverside, 

and two large but crushed individuals are at the Sioux 

City Public Museum. Both are adults that have much of 

the body chamber preserved. The larger one (pl. 7, fig. 8) 

shows the sutures well and closely resembles the large 

specimen from the Woodbine Formation figured by 

Stephenson (1952, pl. 55, figs. 2, 3). The other specimen 

(pl. 6) is on a slab of shaly siltstone with the inner whorls 

of Dunueganoceras pondi Haas. Several other fragments 

of M. dumbli from Riverside are in the collections at the 

Peabody Museum of Natural History. 

Types.-Hypotypes USNM 299174; SCPM F259C, 

F259D. 

Family PLACENTICERATIDAE Hyatt, 1900 

Genus PROPLACENTICERAS Spath, 1926 

Proplacenticeras pseudoplacenta (Hyatt) 

Plate 7, figures 3-5 

1893. Placenticeras placenta (DeKay)? Stanton, U.S. Geological 

(1894) Survey Bulletin 106, p. 169, pl. 39, fig. 1 only. 

1903. Placenticeras pseudoplacenta Hyatt, U.S. Geological Survey 

Monograph 44, p. 216, pl. 43, figs. 3-11; pl. 44. · 

Hyatt defined this species chiefly from the details of 

its fairly simple suture. Reeside (1927, p. 8) summarized 

the features of the shell noting that the flanks were flattened in juveniles and very broadly rounded in adults 
12 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

and that the shell was either smooth or had inconspicuous nodes and ribs. Two of Hyatt's four illustrated 

specimens came from the Tropic Shale in upper Kanab 

valley, Kane County, southwestern Utah, and the others 

came from the Carlile Shale in Colorado and the Pierre 

Shale in South Dakota. Inasmuch as the holotype was 

not selected, a specimen from the Tropic Shale that 

shows many of the features of the species is herein 

designated as the lectotype (Hyatt, 1903, pl. 43, figs. 

3-6). 

Proplacenticeras pseudoplacenta is represented by 

seven specimens from the concretionary limestone at the 

base of the Cretaceous in the Dakota Granite Company's 

quarry east of Milbank, in the SW% sec. 18, T. 120 N., 

R. 47 W., Grant County, S. Dak. (USGS D10415). 

Tubercles are absent, and the flanks are either smooth or 

have very weak falcoid ribs on the outer half. The 

specimens are not large, and none has a whorl height exceeding 68 mm. Associated fossils include Collignoniceras woollgari regulare (Haas) of middle Turonian age. 

The lectotype of P. pseudoplacenta and the holotype 

of P. stantoni are probably from the same locality and 

same part of the Tropic Shale. The specimens of P. 

pseudoplacenta from the Dakota Granite Company's 

quarry were associated with a single specimen of P. stantoni. Proplacenticeras pseudoplacenta and P. stantoni 

are possibly smooth and ornamented forms of the same 

species. Larger collections are needed to evaluate their 

similarities. 

Winchell (1895, p. 53) recorded Placenticeras placenta 

(DeKay) from 11 m below the surface in a well near 

Marshall, Lyon County, Minn. This specimen, in the 

collections of the University of Minnesota, Minneapolis 

(UMIP 2282), is from a clay ironstone concretion andretains some of the nacreous shell material. The specimen 

consists of part of the crushed phragmocone and the 

older part of the body chamber that has a whorl height of 

60 mm at its base. Suture complexity is only moderate, 

like that of specimens of P. pseudoplacenta. The 

specimen probably came from the noncalcareous part of 

. the Carlile Shale. 

Types.-Hypotypes USNM 299169, 299170. 

Proplacenticeras stantoni (Hyatt) 

Plate 7, figures 1, 2 

1893. Placenticeras placenta (DeKay)? Stanton, U.S. Geological 

(1894) Survey Bull. 106, p. 169, pl. 39, figs. 2, 3 (not fig. 1). 

1903. Placenticeras stantoni Hyatt, U.S. Geological Survey 

Monograph 44, p. 214. 

The holotype of Proplacenticeras stantoni is an internal mold of a phragmocone from the Tropic Shale of the 

upper Kanab valley in Kane County, southwestern 

Utah. Nodate umbilical tubercles and clavate ventrolateral tubercles are conspicuous. The flanks are smooth 

except for very weak falcoid ribs on the outer half. 

Neither Stanton nor Hyatt illustrated the suture. The 

specimen probably came from the highly fossiliferous 

limestone concretions in the lower part of the Tropic 

Shale (Stanton, 1893, p. 35) which have the 

Sciponoceras gracile (Shumard) fauna oflatest Cenomanian age. 

A phragmocone from the concretionary limestone at 

the base of the Cretaceous in the Dakota Granite Company's quarry east of Milbank, in the SW% sec. 18, T. 

102 N., R. 47 W., S. Dak (USGS D10415), seems assignable toP. stantoni. The specimen is a little stouter 

than the holotype, and the ribbing is more pronounced. 

Associated fossils include Collignoniceras woollgari 

regulare (Haas). 

Type. -Hypotype USNM 299168. 

Family ACANTHOCERATIDAE de Grossouvre, 1894 

Genus DUNVEGANOCERAS Warren and Stelck, 1940 

Dunveganoceras pondi Haas 

Plate 6; plate 9; plate 10, figure 1; plate 15, figure 1; text figure 2 

1949. Dunveganoceras pondi Haas, Bulletin of the American 

Museum of Natural History, v. 93, art. 1, p. 22, pl. 8, figs. 1-

5, 8; pl. 9, figs. 1, 3, 4; pls. 10-14; text figs. 11-13, 16, 17. 

1979. Dunveganoceras pondi Haas. Merewether, Cobban, and 

Cavanaugh, The Mountain Geologist, v. 16, no. 3, pl. 4. 

Dunveganoceras pondi, of late Cenomanian age, differs from other species of the genus in having ribs on the 

adult body chamber that are depressed in the middle of 

the venter. The inner whorls are like those of the other 

species in having bullate umbilical tubercles, nodate or 

clavate inner ventrolateral tubercles and clavate outer 

ventrolateral tubercles. On the last whorl of the 

phragmocone, the location of the umbilical bullae 

gradually shifts, with growth, to the flank, and near the 

end of the phragmocone, the ventrolateral tubercles 

merge into blunt horns. The ribs on the body chamber 

are straight and rectiradiate, and, toward the aperture, 

they become flange like and replace the horns. These 

ribs are well rounded and much narrower than the interspaces. The ribs slope toward the venter, which gives the 

whorl section (fig. 2) a trapezoidal appearance. 

Dunveganoceras pondi has a typical acanthoceratid 

suture (pl. 9). The first lateral saddle is broad and bifid, 

and the lateral lobe is moderately broad, rectangular, 

and bifid. 

A few specimens of D. pondi have been found in ferruginous siltstone concretions in the basal part of the 

Graneros Shale in the claypits at Riverside, Iowa. A very 

good adult specimen is on display at the Sioux City 

Public Museum (pl. 9). Most of the body chamber of an 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 13 

... ,-.... ----- ---

I 

I ' 

I 

I 

I 

I 

I 

I 

I 

, 

, , 

"' " , , 

I , 

, 

"' 

, ..... 

" .... .... ' ..... .... .... 

" ' ' ' ' \ 

\ 

\ 

\ 

\ 

\ 

\ 

' ' ' 

I ' 

FIGURE 2.-Part of whorl section, natural size, of Dunveganoceras pondi Haas (see this 

report, pl. 10, fig. 1), from the basal part of the Graneros Shale at the Sioux City Brick and 

Tile Company's claypit, Riverside, Iowa. Hypotype YPM 14897. Dashed line is intercostal 

section. 

adult is in the collections of the Peabody Museum of 

Natural History at Yale University, New Haven, Conn. 

(pl. 10, fig. 1). Part of a septate inner whorl was found as 

float at a roadcut in the. Graneros Shale 14 km northeast 

of Sioux City, Iowa (USGS D10412; pl. 15, fig. 1). All 

specimens were associated with Inoceramus prefragilis 

stephensoni Kauffman and Powell, and those from 

Riverside were also with Metengonoceras dumbli 

(Cragin). The ammonite referred to as Prionocyclus sp. 

by Bain (1896, p. 274) from a claypit at Riverside is 

probably D. pondi. 

Type.-Hypotypes YPM 14897; USNM 299183; 

SCPM F259C. 

Dunveganoceras hagei Warren and Stelck 

Plate 10, figure 2; plate 11; plate 12, figures 6, 7; text figures 3, 4 

1944. Metacalycoceras? sp. Bergquist, Journal of Paleontology, v. 18, 

no. 1, p. 29. 

1944. Acanthoceras? sp. Bergquist, Journal ofPaleontology, v. 18, no. 

1, p. 29. 

1951. Dunveganoceras cf. pondi Haas. Haas, American Museum 

Novitates No. 1490, p. 2, fig. 1. 

1955. Dunveganoceras hagei Warren and Stelck, Research Council of 

Alberta Report No. 70, p. 69, pl. 5, fig. 1. 

Dunveganoceras hagei, of late Cenomanian age, is 

represented by many fragments at the Department of 

Geology and Geophysics, University of Minnesota, Minneapolis, and by a large nearly complete specimen at the 

Department of Geology, University of Minnesota, 

Duluth. All are from the Coleraine Formation of the 

western part of the Mesabi Range, Itasca County. 

The holotype of D. hagei came from Dunvegan Creek, 

southwest of Dunvegan, in the Peace River area of 

western Alberta, Canada. The specimen, 260 mm in 

diameter, is most of an adult that has one-half of a whorl 

of the body chamber preserved. The umbilicus has a 

diameter of 90 mm (umbilical ratio=0.35). Ribs are 

straight, rectiradiate to prorsiradiate, and number 19 on 

the last whorl. Inner and outer rows of ventrolateral 

tubercles persist to the older part of the body chamber, 

where the inner row gradually disappears. The outer row 

continues on the rest of the preserved part of the body 

chamber and borders a slightly flattened venter. 

Fragments of Dunueganoceras at the University of 

Minnesota, Minneapolis, seem assignable to D. hagei. 

One of the larger fragments, an internal mold of ferruginous sandstone, is shown on plate 12. This specimen, 

the older one-third of an adult body chamber, closely 

matches in size and ornamentation the older part of the 

body chamber of the holotype. The whorl section (fig. 3) 

is like that described by Warren and Stelck (1955, p. 69) 

for the older part of the body chamber. The Minnesota 

specimen was described by Bergquist (1944, p. 29) as 

Acanthoceras sp. 

The nearly complete specimen at the University of 

Minnesota, Duluth, was described by Haas (1951, p. 2, 

fig. 1) as Dunveganoceras cf. pondi Haas. This specimen 

(pl. 10, fig. 2; pl. 11; text fig. 3), an internal mold of very 

hematitic sandstone, is slightly crushed. Haas reported 

its diameter as about 378 mm and its umbilical ratio as 

0.345. Only traces of sutures are visible, and the base of 

the body chamber is not easily determined. Haas 

believed that the last septum was at a diameter of about 

300 mm, which may be correct. Ribs, which number 20 
14 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

I 

\ 

/,..~-, 

, ....... -... ,' ........ ~ ' ~ ' \ 

' 

/ ,' \ I I \ 

I I \ 

I \ 

I 

I 

I 

I 

I 

I 

, 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

' \ 

\ 

\ 

' \ 

I 

I 

I 

I 

I 

\ 

I 

I 

I 

I 

I 

FIGURE 3.-Whorl section, natural size, of Dunveganoceras 

hagei Warren and Stelck (see this report, pl. 12, figs. 6, 

7), from the Coleraine Formation at the Hill Annex 

mine, Calumet, Minn. UMIP 5058. Inner dashed line is 

intercostal section. 

on the last whorl, are straight, rectiradiate, narrowly 

rounded, and narrower than the interspaces. All ribs 

begin at the umbilical shoulder and cross the entire 

flank. No secondary ribs are visible. Inner and outer 

ventrolateral tubercles are present on the penultimate 

whorl and on the first part of the outer whorl. As the 

outer whorl enlarges, the inner row of ventrolateral 

tubercles disappears, and the outer row borders the flattened venter for a short distance before merging with the 

ribs, which become high and almost pointed on crossing 

the venter. The cross section of the body chamber of this 

specimen is a pointed arch (fig. 4) like that of the 

holotype of D. albertense (Warren, 1930b, pl. 1, fig. 2). 

Such a section is not present on the extant part of the 

body chamber of the holotype of D. hagei, although Warren and Stelck (1955, p. 69) observed a change in the 

whorl section at the last preserved rib to that of "a 

trapezoidal outline with the ventral region slightly depressed." Quite likely, the whorl section of the succeeding ribs would be a pointed arch. 

Haas (1951, [g. 1) showed only a lateral view of the 

Duluth specimen. The opposite side (pl. 11) is visible in 

an illustration in Geotimes (1963, p. 14) that concerns 

geologic exhibits at the University of Minnesota, Duluth. 

Types.-Hypotype UMIP 5058; Univ. Minn., Duluth, 

unnumbered. 

Genus METOICOCERAS Hyatt, 1903 

Metoicoceras bergquisti Cobban, n. sp. 

Plate 8, figures 1-4; plate 12, figures 1-5; plate 13; plate 14, figures 

1-5, 10-15 

1944. Metoicoceras aff. M. swallovi (Shumard). Bergquist, Journal of 

Paleontology, v. 18, no. 1, p. 30, pl. 10, figs. 10-12. 

Metoicoceras is present as internal molds of ferruginous siltstone in the basal part of the late Cenomanian Coleraine Formation in the Mesabi Range in 

northern Minnesota. Of the 15 specimens available, 11 

represent a smooth to weakly ribbed stout form that has 

a flat to very broadly rounded smooth venter. The other 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

.... -... , ' , ' / ' , ' ~ ' / ' I \ 

I \ 

I \ I \ 

I \ 

I \ 

I \ 

I \ 

I ' I \ 

I \ 

I \ 

I \ I \ 

I \ 

/ \ I \ 

I \ 

I \ I \ 

I \ 

I \ 

I \ 

I I 

I I 

I 

I 

' 

FIGURE 4.-Whorl section, natural size, of the body chamber of 

Dunveganoceras hagei Warren and Stelck (see this report, pl. 10, 

fig. 2; pl. 11), from the Coleraine Formation at the Hill Annex 

mine, Calumet, Minn. Inner dashed line is intercostal section. 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 15 

specimens have stronger ornamentation. Bergquist 

(1944, pl. 10, figs. 10-12) illustrated a single specimen of 

each form. Inasmuch as the two forms occur together, I 

believe they represent a single species. 

The more ornamented form (pl. 12, figs. 1-3) has prorsiradiate ribs that are highest and broadest on the outer 

part of the flank. The ribs are rounded and narrower 

than the interspaces, and number about 14 or 15 per onehalf whorl. Most begin on the inner part of the flank, but 

some arise at midflank. On the early whorls (Bergquist, 

1944, pl. 10, fig. 12), the ribs have double ventrolateral 

tubercles, an inner row of nodate to bullate ones and an 

outer row of clavate ones. The inner tubercles weaken 

and disappear where the shell has a small diameter, but 

the outer ones may persist until the diameter is as much 

as 80 mm. 

The smoother form consists of fragments that (1) lack 

ornamentation (pl. 14, figs. 4, 5, 10, 11), (2) have smooth 

flanks and very weak outer clavate ventrolateral tubercles (pl. 14, figs. 1, 2), or (3) have very weakly ribbed 

flanks and no ventrolateral tubercles (pl. 8, figs. 3, 4; pl. 

13). The innermost whorls are not preserved in the 

specimens studied. At the smallest diameter observed 

(about 20 mm), the flanks are smooth and only weak 

clavate outer ventrolateral tubercles are present. 

The holotype (pl. 14, figs. 1-3) is the older half of a 

small adult body chamber, which has a whorl height of 

38 mm and a thickness of 24.5 mm. The flanks are 

slightly rounded and smooth, and the smooth, flat venter 

is bordered by very weak outer clavate ventrolateral 

tubercles. A latex cast (pl. 14, fig. 3) of the last inner 

whorl displays weak ribs on the outer half of the flank. 

These ribs are slightly accentuated where inner 

ventrolateral tubercles should occur, and they terminate 

in well-defined outer ventrolateral clavi. About 15 ribs 

occur per half whorl. 

External sutures are visible on several specimens (pl. 

12, figs. 1, 5; pl. 14, figs. 4, 5, 10, 11). These sutures, as 

well as those visible on the two specimens figured by 

Bergquist (1944, pl. 10, figs. 10-12), closely resemble the 

sutures of some specimens of Metoicoceras whitei, M. 

gibbosum, and M. kanabense illustrated by Hyatt (1903, 

pl. 13, fig. 5; pl. 14, figs. 3, 8; pl. 15, figs. 7, 8, 11). 

Metoicoceras bergquisti attained a large size. The 

largest specimen studied (pl. 13) consists of the younger 

part of a body chamber, which has a whorl height of 

about 96 mm. 

The ornamented form of M. bergquisti resembles M. 

gesliniatum (d'Orbigny), as 'interpreted by Juignet, 

Kennedy, and Wright (1973, p. 234-236), in having 

about the same rib density and in losing the inner 

ventrolateral tubercles at a small diameter; but the illustrated specimens of M. gesliniatum are more compressed and do not grade into a smooth form. 

Types.-Holotype UMIP 9004; paratypes UMIP 5061, 

6178, 9003, 9005a, 9005b, 9008; USNM 299173, 299182. 

Genus WATINOCERAS Warren, 1930 

Watinoceras coloradoense (Henderson) 

Plate 15, figure 12 

1908. Acanthoceras coloradoensis Henderson, U.S. National 

Museum Proceedings, v. 34, no. 1611, p. 259, pl. 13, figs. 10, 

11. 

1972. Watinoceras coloradoense (Henderson). Cobban and Scott, 

U.S. Geological Survey Professional Paper 645, p. 76, pl. 27, 

figs. 11-19; pl. 28, figs. 1-3, 5-9; text figs. 35-37. 

A single poorly preserved specimen from the 

Greenhorn Formation at Lake Traverse, Minn. (USGS 

D10578), seems assignable to Watinoceras coloradoense. 

The specimen, about 55 mm in diameter, is an internal 

mold in a piece of hard gray limestone. Ribs are 

preserved on part of the last whorl and on the next to the 

last of the inner whorls. The ribs are straight and slightly 

prorsiradiate. They number 20 per half whorl at a whorl 

diameter of about 18.5 mm, and about 14 at a diameter 

of 55 mm. Cobban and Scott (1972, p. 76) noted that 

specimens from Pueblo, Colo., have 15-20 ribs per half 

whorl at diameters of from 10 to 30 mm, and 10-13 ribs at 

diameters of from 50 to 60 mm. On the ribbed inner 

whorl, every other rib begins at the umbilicus much like 

some of the ribs on one of the small specimens illustrated 

by Cobban and Scott (1972, pl. 28, fig. 2). On the outer 

whorl, every other rib (primary) begins from a bullate 

umbilical tubercle, and all ribs have inner and outer 

ventrolateral tubercles. The outer ones are clavate, but 

the inner ones are too damaged to reveal their shape. 

The specimen was found as float on the Greenhorn 

Formation. At Pueblo, Colo., W coloradoense is known 

only from one bed of limestone at the top of the lower 

one-third of the Bridge Creek Limestone Mem her of the 

Greenhorn Formation (Cobban and Scott, 1972, p. 76). 

Other fossils found in this bed at Pueblo include 

Mytiloides aff. M. duplicostatus (Anderson), Puebloites 

spiralis Cobban and Scott, Ampakabites collignoni Cobban and Scott, Vascoceras (Greenhornoceras) birchbyi 

Cobban and Scott, Fagesia sp., Neoptychites xetriformis 

Pervinquiere, and N. cephalotus (Courtiller). This is 

very definitely an early Turonian assemblage. 

Type.-Hypotype USNM 299190. Collected by Jayne 

Sieverding and Sheila Stenzel, east shore of Lake 

Traverse, in the NE 1;4 SE 1

/4 sec. 2, T. 125 N., R. 49 W., 

Traverse County, Minn. 
16 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

Family COLLIGNONICERATIDAE Wright and Wright, 1951 

Genus COLLIGNONICERAS Breistroffer, 1947 

Collignoniceras woollgari regulare (Haas) 

Plate 15, figures 2-4, 7-11 

1876. Prionocyclus (Prionotropis) woollgari (Manetll). Meek,. U.S. 

Geological Survey of the Territories (Hayden) Report 9, p. 

455, pl. 6, fig. 2; pl. 7, figs, 1-3. 

1946. Prionotropis woollgari (Mantell) and varieties. Haas, Bulletin 

of the American Museum of Natural History, v. 86, art. 4, p. 

150, pls. 11, 12; pl. 13, figs. 1-3, 5-18 (not figs. 4, 19); pl. 14, 

figs. 1-10, 12-16 (not fig. 11); pl. 15, figs. 1-6, 9, 10 (not figs. 

7, 8); pls. 16, 17; pl. 18, figs. 1, 2, 7-9; pl. 24, fig. 1; text figs. 

1-4, 6--44, 46--91. 

The cotypes of Collignoniceras woollgari woollgari, 

from the Middle Chalk of England, were described by 

Mantell (1822, p. 197, pl. 21, fig. 16; pl. 22, fig. 7) as Ammonites woollgari. Wright and Wright (1951, p. 35) 

designated the larger specimen as the lectotype. This 

specimen, an adult, is moderately evolute and ornamented by prorsiradiate, widely separated, straight 

ribs that have, on the inner whorls, bullate umbilical 

tubercles, nodate inner ventrolateral tubercles, and 

clavate outer ventrolateral tubercles. A clavate siphonal 

tubercle accompanies each rib. On the body chamber, 

the umbilical tubercles migrate outwards from the umbilicus with growth and merge into the ribs, and the 

ventrolateral tubercles fuse into conspicuous horns. 

Secondary ribs develop on the outer part of the last 

whorl, and each is represented by a low clavate siphonal 

tubercle. Opposite ventrolateral horns on the body 

chamber are joined by a pair of low ribs that bear 

siphonal clavi. 

Most of the ammonites from the Carlile Shale of the 

Great Plains region that have been referred to C. woollgari differ from the lectotype in lacking secondary ribs on 

the outer whorl and in lacking the looped ribs connecting 

opposite ventrolateral horns. Haas (1946, p. 151-196), 

and later Matsumoto (1965, p. 12-15), documented great 

intraspecific variation within local populations of the 

American form. Haas named several forms as varieties 

including the varieties intermedia and regularis, which 

are in the middle of the range in variation. Cobban and 

Hook (1979, p. 6) determined that the common 

American form of C. woollgari was a little younger than 

the European form. Because of this difference in age, as 

well as differences in the ornamentation of the adult ammonites, Cobban and Hook considered the American 

form as a chronologie subspecies of the European C. 

woollgari. The name C. woollgari regulare (Haas) was 

applied to this late form of the species. 

Collignoniceras woollgari regulare has been well illustrated by Meek (1876), Haas (1946), Matsumoto 

(1965), and Cobban and Hook (1979). Of the many 

specimens illustrated by Haas, however, three are not 

this subspecies. Two of the specimens (Haas, 1946, pl. 

13, figs. 4, 19, pl. 15, figs. 7, 8, text figs. 5, 45), from the 

Blue Hill Member of the Carlile Shale of Kansas, are 

Prionocyclus hyatti (Stanton); and the third (Haas, 

1946, pl. 14, fig. 11) is Plesiacanthoceras wyomingense 

(Reagan) from the Belle Fourche Shale. 

Typical specimens of C. woollgari regulare occur in a 

hard bed of gray limestone that rests unconformably on 

Precambrian granite in the Dakota Granite Company's 

quarry east of Milbank in the SW% sec. 18, T. 120 N., R. 

47 W., Grant County, S. Dak. (USGS D10415). Associated cephalopods include Baculites yokoyamai 

Tokunaga and Shimizu (pl. 14, figs. 6-8), Scaphites 

delicatulus sloani Cobban, n. subsp. (pl. 5, figs. 12-15, 

18-23), Tragodesmoceras carlilense Cobban (pl. 5, figs. 

4, 5), Proplacenticeras pseudoplacenta (Hyatt) (pl. 7, 

figs. 3-5), P. stantoni (Hyatt) (pl. 7, figs. 1, 2), Binneyites carlilensis Cobban (pl. 5, figs. 1-3), and Actinocamax sp. (pl. 7, figs. 6, 7). Darton (1905, p. 129, 131, 

135; 1909, p. 49, 52) had earlier recorded "Prionotropis 

woolgari" from shallow water wells in the Milbank area. 

Collignoniceras woollgari regulare was probably collected far east of Milbank. Kloos (1872, p. 23) collected 

impressions of ammonites in shale from a well dug about 

3 km south of Richmond in the Sauk River valley in 

south-central Minnesota. These specimens were sent to 

F. B. Meek, who reported Ammonites percarinatus Hall 

and Meek and Scaphites laruaeformis Meek and 

Hayden. Ammonites percarinatus (Hall and Meek, 1856, 

p. 396, pl. 4, figs. 2a, b) was regarded as a synonym of 

"Prionocyclus (Prionotropis) woolgari" by Meek (1876, 

p. 455). Scaphites laruaeformis is a common associate of 

C. woollgari regulare in the Black Hills area of South 

Dakota and Wyoming. 

Impressions of C. woollgari regulare are present in the 

cores from the Iowa Geological Survey-U.S. Geological 

Survey test hole 9-D in the NE 114NE% sec. 5, T. 95 N., 

R. 47 W., Sioux County, Iowa. The impressions, all 

juvenile ammonites, occur in calcareous shale 4.6-12.8 m 

above the base of the Carlile Shale. 

White (1873a, p. 188; 1873b, p. 67) may have seen 

specimens of C. woollgari regulare obtained from the 

glacial drift in northeastern Iowa. Among fossils from the 

"bluish clay of the unaltered drift" near Lime Springs in 

Howard County, White recorded Belemnitella and Ammonites ("2 species"). The first is probably Actinocamax, and the latter may have included C. woollgari regulare inasmuch as a little later Meek (1876, p. 

457) noted that White had seen "Prionocyclus 

(Prionotropis) woollgari" in the drift of northern Iowa. 

A badly distorted specimen in a limestone concretion 

from the glacial drift in southwestern Minnesota may be 

C. woollgari regulare. This specimen, which is in the col-
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 17 

lections at the University of Minnesota, Minneapolis 

(UMIP 8898), came from the NEV4 sec. 32, T. 115 N., R. 

38 W ., Yellow Medicine County. 

Ammonites that are probably C. woollgari regulare 

have been found in the glacial drift as far east as Illinois. 

Worthen (1890, p. 4, fig. 5) illustrated part of a whorl (pl. 

15, fig. 11) that has the narrow, widely spaced, prorsiradiate ribs typical of C. woollgari. The specimen was 

found in the "blue clays of the drift at Golden Bluff 

Vineyards, about two miles south of Warsaw." Other illustrated fossils from this locality include part of a 

belemnite guard (Worthen, 1890, p. 4, fig. 4) that resembles Actinocamax manitobensis (Whiteaves), a species 

that is widely distributed with C. woollgari regulare in 

the lower part of the Carlile Shale in the northern and 

central Great Plains region. 

Some reports of C. woollgari may be based on misidentifications of juvenile Subprionocyclus percarinatus 

(Hall and Meek). Todd (1908, p. 2) reported 

"Prionotropis woolgari" from the Carlile Shale in 

southeastern South Dakota and much farther northwest 

near Redfield (Todd, 1909, p. 4). Todd (1903, p. 3) also 

reported that "Prinotropis" (sic) was found southeast of 

Mitchell "at depth of several feet 11

/z miles north of 

Elmspring" (probably in sec. 28, T. 101 N., R. 58 W., 

Hanson County, S. Dak.). 

Types.-Hypotypes USNM 299184-299189. 

Collignoniceras vermilionense (Meek and Hayden) 

Plate 5, figures 38-42 

1860. Ammonites vermilionensis Meek and Hayden, Proceedings of 

the Academy of Natural Sciences of Philadelphia, v. 7, p. 

177. 

1876. Mortoniceras? vermilionense (Meek and Hayden). Meek, U.S. 

Geological Survey of the Territories (Hayden) Report 9, p. 

450, pl. 7, fig. 2a, b. 

1893. Mortoniceras vermilionense (Meek and Hayden). Stanton, 

(1894) U.S. Geological Survey Bulletin 106, p. 180, pl. 44, fig. 1. 

1898. Mortoniceras vermilionense (Meek and Hayden). Logan, 

Kansas University Geological Survey, v. 4, p. 472, pl. 104, 

fig. 1. 

1927. Prionotropis vermilionensis (Meek and Hayden). Reeside, U.S. 

Geological Survey Professional Paper 150-A, p. 10. 

The holotype (pl. 5, fig. 38), and only specimen 

described, came from a limestone concretion in the 

Carlile Shale on the Missouri River a few kilometers upstream (west-northwest) of the type locality (Volcano 

Hill, Nebr.) of Hall and Meek's Ammonites percarinatus. Meek and Hayden (1860, p. 177) reported that 

the holotype of A. vermilionensis had been collected at 

the mouth of Vermilion (now spelled Vermillion) River. 

The Carlile Shale formerly cropped out along the south 

bank of the Missouri River opposite the mouth of the 

Vermillion River (Condra, 1908, pl. 5, fig. B). 

Meek and Hayden's description of the holotype is as 

follows (1860, p. 177): 

Shell compressed discoidal; umbilicus large, very shallow, and showing about four-fifths of each inner whorl; volutions five or more, rather 

sharply carinated around the middle of the dorsum, and ornamented 

on each side by nearly straight, simple, moderately strong, obtuse 

costae, which show a tendency to develop nodes at each extremity. 

Greatest diameter 1.05 inches; convexity about 0.29 inch. / 

In addition to these observations, the holotype has an 

umbilical ratio of 0.44 and about 21 prorsiradiate, 

slightly flexuous ribs on the last whorl and 25 on the 

preceding whorl. The ribs are mostly of equal 

prominence, and most have umbilical bullae. Each rib 

rises into a nodose thickening at the ventrolateral 

shoulder and then bends forward onto the venter. 

Specimens closely resembling the holotype occur 

sparsely in septarian limestone concretions in the Carlile 

Shale in southeastern South Dakota and northeastern 

Nebraska. Two specimens from Volcano Hill, Dixon 

County, Nebr. (USGS D10404), are shown on plate 5. 

One specimen (pl. 5, figs. 39, 40) has a diameter of 56 

mm, umbilical width of 25.5 mm (umbilical ratio=0.45), 

and rib counts per whorl of 28 at 14 mm diameter, 20 at 

31 mm, and 19 at 56 mm. Ribs are slightly prorsiradiate 

and of equal strength. The ribs on the outer whorl have 

umbilical bullae and ventrolateral swellings. A conspicuous clavate tubercle is present on the keel for each 

rib. The other specimen (pl. 5, figs. 41, 42) has a 

diameter of 71.5 mm, umbilical width of 31 mm (umbilical ratio=0.43), and rib counts per whorl of 30 at 16 

mm diameter and 16 at 36 mm and 70 mm diameters. 

On this individual, the serrations on the keel are subdued. Ribs are straight, rectiradiate, and uniform in 

strength. The ribs on the last two whorls have umbilical 

bullae, and the ribs on the outer whorl have prominent 

ventrolateral nodes on the older part and ventrolateral 

horns on the younger part. The two illustrated specimens 

are probably small adults. Some other specimens attained much larger sizes. A phragmocone from a septarian limestone concretion in the Carlile Shale at Union 

County State Park, Union County, S. Dak. (USGS 

D10410), is 100 mm in diameter. 

The suture of C. vermilionense, well illustrated by 

Meek (1876, pl. 7, fig. 2b), is moderately simple and has 

a very broad bifid first lateral saddle and narrow rectangular lateral lobe. 

Collignoniceras vermilionense is associated with 

Subprionocyclus percarinatus (Hall and Meek) in the 

Carlile Shale (middle Turonian age) in southeastern 

South Dakota and northeastern Nebraska. Ammonites 

identified by Logan (1898, p. 473) as Mortoniceras ver-
18 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

milionense from the "Fort Benton limestone" (Bridge 

Creek Member of the Greenhorn Formation) and "Septaria horizons" (Blue Hill Member of Carlile Shale) of 

Kansas represent other genera and species. 

Types.-Holotype USNM 224; hypotypes USNM 29-

9166, 299167. 

Genus SUBPRIONOCYCLUS Shimizu, 1932 

Subprionocyclus percarinatus (Hall and Meek) 

Plate 5, figures 26-37 

1856. Ammonites percarinatus Hall and Meek, American Academy 

of Arts and Sciences Memoirs, n. ser., v. 5, p. 396, pl. 4, fig. 

2a, b. 

1876. Prionocyclus (Prionotropis) woollgari (Mantell). Meek, U.S. 

Geological Survey of the Territories (Hayden) Report 9, p. 

455, 457. 

1893. Prionotropis woolgari (Mantell). Stanton, U.S. Geological 

(1894) Survey Bulletin 106, p. 174. 

1946. Prionotropis woolgari Meek (?non Mantell). Haas, Bulletin of 

the American Museum of Natural History, v. 86, art. 4, p. 

150, 151, 153. 

1952. Collignoniceras woolgari (Mantell). Stephenson, U.S. 

(1953) Geological Survey Professional Paper 242, pl. 12, fig. 3. 

The type lot consists of small crushed specimens not 

exceeding 25 mm in diameter (Haas, 1946, p. 153). The 

specimens came from "* * * Five miles below the mouth 

of Vermilion River on the Missouri; in division No. 2 of 

Section" (Hall and·Meek, 1856, p. 396). In that area, the 

only outcrops are of the Carlile Shale and are on the 

northeast side of Volcano Hill near the center of sec. 3, T. 

31 N., R. 5 E., Dixon County, Nebr. (USGS D10404). 

Specimens from this locality are comparable to the types 

and occur as sparse imprints in gray noncalcareous 

clayey shale (pl. 5, fig. 35) and, more rarely, as uncrushed specimens in gray septarian limestone concretions (pl. 5, figs. 26-33, 36, 37). 

Subprionocyclus percarinatus is a compressed, 

densely ribbed, keeled ammonite ornamented by 

"thirty-eight to forty-five prominent flexuous sharp ribs 

some of which originate in the umbilicus, and others 

upon the latera-ventral margin, and all extend to the 

dorso-lateral edge, where they bend abruptly forward, 

and terminate before reaching the dorsal line, which is 

marked by a thin sharp carina extending to the aperture. 

Ribs thickened and sometimes nodose towards the 

periphery" (Hall and Meek, 1856, p. 396). Two 

specimens were illustrated by Hall and Meek, a very 

small specimen and a much larger one about 25 mm in 

diameter. The latter one is herein designated as the lectotype, and Hall and Meek's drawing of it is reproduced 

on plate 5, figure 34. 

A limestone concretion from the type locality (USGS 

D10404) of S. percarinatus contained seven specimens 

suitable for measurements; six are shown on plate 5, 

figures 26-33, 36, 37. These specimens, from 12 to 32 mm 

in diameter, have umbilical ratios of 0.32-0.45 and rib 

counts per one-half whorl of 18-25. The ribs are narrow 

and flexuous like those of the types, and every second or 

third one, or rarely every fourth or fifth, is higher and 

begins at the umbilicus. These higher ribs (primaries) 

have umbilical bullae. All ribs bend forward at the 

ventrolateral shoulder and disappear at the base of the 

keel. Two specimens have a double row of ventrolateral 

tubercles of equal strength, another has an inner row 

stronger than the outer, two have only outer ones, and 

the other two have none-although the ends of the ribs 

are slightly accentuated where the outer ventrolateral 

tubercles should be. The inner ventrolateral tubercles 

are nodate, and the outer ones are nodate or clavate. The 

keel is serrate, and each serration (clavate tubercle) corresponds to a rib. Sutures are clearly visible on only one 

individual, which has broad bifid first and second lateral 

saddles and a narrow, poorly divided lateral lobe. 

Subprionocyclus percarinatus seems to be a small 

species. All seven specimens from the limestone concretion include parts of the body chambers. Diameters at 

the base of the body chamber range from 10 to 22 mm. 

Hall and Meek's Ammonites percarinatus seems best 

assigned to Subprionocyclus. Wright and Matsumoto 

( 1954, p. 129) and later Matsumoto ( 1959, p. 108, 109) 

summarized Subprionocyclus noting that ribs are 

primary and secondary and usually flexuous, and that 

the inner ventrolateral tubercles may weaken on the 

outer whorls. Most specimens from the limestone concretions collected at Volcano Hill fit this description, 

although the single individual that has inner 

ventrolateral tubercles dominant over the outer ones 

suggests a link to Collignoniceras. 

Hall and Meek (1856, p. 382, 383, 387, 388) described 

the new species Cytherea orbiculata, C. tenuis, 

Inoceramus conradi, and I. fragilis from the same 

locality that yielded the types of their Ammonites percarinatus. The small ammonites, identified as Collignoniceras woolgari (Mantell) by Stephenson (1952, pl. 

12, fig. 3), on the piece of gray shale that contains the 

holotype of I. fragilis, are Subprionocyclus percarinatus. 

Impressions of small ammonites that seem to be S. 

percarinatus occur in outcrops of gray noncalcareous 

Carlile Shale in a stream cut along Brule Creek (N V2 sec. 

32, T. 94 N., R. 50 W.), in Union County State Park in 

southeastern South Dakota. Specimens from this 

locality are in the collections of the Department of Earth 

Science and Physics, University of South Dakota, Vermillion. Similar impressions also occur in gray noncalcareous shale in an excavation southeast of Mitchell, 

in the SE%NE1

/4 sec. 8, T. 102 N., R. 59 W., Hanson 

County, S. Dak. (USGS D10701), where the shale is distorted by glacial action and may be transported. 

Distorted shale of a different color (yellowish gray) at 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 19 

this locality contains impressions of Inoceramus 

prefragilis stephensoni Kauffman and Powell of late 

Cenomanian age. 

Two small impressions of finely ribbed ammonites, 

which may be S. percarinatus, were found in noncalcareous clay shale in the lower part of the Carlile 

Shale, on the southeast bank of Lake Traverse, Minn. At 

this locality, in the NE 1

/4SE 1/4 sec. 2, T. 125 N., R. 47 

W., Traverse County, the upper part of the Greenhorn 

Formation and some of the Carlile Shale crop out 

(Shurr, 1979). Much farther southeastward in Minnesota, impressions of similar small ammonites were 

found in noncalcareous gray shale from 3 m below the 

surface, at a stock pond excavation in the SE V4 sec. 16, 

T. 110 N., R. 39 W., Redwood County. These specimens 

are in the collections at the University of Minnesota, 

Minneapolis. 

The Cretaceous seaway during the time of S. percarinatus may have covered much of Minnesota. A clay 

ironstone concretion found in the glacial drift south of 

Minneapolis contained an ammonite that may be S. percarinatus (pl. 15, figs. 5, 6). 

Specimens identified as Ammonites percarinatus were 

recorded by Marcou (1867, p. 61, pl. 1) from the lower 

part of the Big Sioux River valley ·along the border of 

South Dakota and Iowa. According to the columnar section shown by Marcou (1867, pl. 1), the ammonites came 

from a unit of limestone containing "Inoceramus 

problematicus." This limestone unit is probably the upper part of the Greenhorn Formation, and the inoceramid is probably Mytiloides mytiloides (Mantell). 

The ammonites observed were probably juveniles of 

some other species, possibly Collignoniceras woollgari 

(Mantell). Impressions of small ammonites, recorded as 

Prionocyclus wyomingensis by Wilder (1900, p. 113), 

from the Carlile Shale of this area are probably 

Subprionocyclus percarinatus. 

Hayden (1873, p. 53) reported "Ammonites 

peracutus" [S. percarinatus] from the "Fort Benton" 

near the mouth of "Iowa Creek." The Dakota Formation, 

Graneros Shale, and Greenhorn Formation crop out near 

the mouth of Aowa Creek (formerly Iowa Creek) in 

eastern Dixon County, Nebr., and the ammonite 

reported by Hayden is probably some other species from 

the Graneros Shale. 

Meek (1876, p. 455, 457) believed that Ammonites percarinatus Hall and Meek, 1856, w~s a synonym of A. 

woollgari Mantell, 1822, and that the correct name was 

Prionocyclus (Prionotropis) woollgari (misspelled 

woolgari). This conclusion was accepted by Stanton 

(1893, p. 174), and consequently, ammonites from the 

Carlile Shale of southeastern South Dakota and 

northeastern Nebraska were identified by Stanton as 

Prionocyclus woolgari (sic) (Todd, 1904, p. 571) or 

Prionotropis woolgari (sic) (Todd, 1908, p. 2). Meek 

(1876, p. 457) noted earlier that C. A. White had found 

this ammonite in the glacial drift of northwestern Iowa. 

The exact position of Subprionocyclus percarinatus in 

the ammonite zonation of the Western Interior cannot be 

determined from collections of fossils from southeastern 

South Dakota and northeastern Nebraska. However, on 

the south flank of the Black Hills in southwestern South 

Dakota and on the Chadron arch in northwestern 

Nebraska, S. percarinatus has been found in limestsone 

concretions in the Carlile Shale immediately above beds 

containing Collignoniceras woollgari regulare (Haas). 

The age of S. percarinatus is probably middle Turonian. 

Types.-Hypotypes USNM 299159-299165. 

Genus PRIONOCYCLUS Meek, 1876 

Prionocyclus novimexicanus (Marcou) 

1858. Ammonites novi-mexicani Marcou, Geology of North America, 

p. 35, pl. 1, figs. 2, 2a. 

1946. Prionocyclus wyomingensis var. elegans Haas, American 

Museum of Natural History Bulletin, v. 86, art. 4, p. 200, pl. 

19, figs. 1-7, 11-14; pl. 20, fig. 4; pl. 21, figs. 1-3, 5; pl. 22, 

figs. 1, 2; text figs. 98-104. 

1979. Prionocyclus novimexicanus (Marcou). Hook and Cobban, 

New Mexico Bureau of Mines and Mineral Resources Annual Report 1977-1978, p. 35, figs. 3E-L. 

This ornate, fairly evolute, compressed ammonite has 

abundant prorsiradiate closely spaced flexuous ribs and 

a conspicuous serrate keel. Ribs are primary and secondary, and most primaries arise from umbilical bullae, 

cross the flank with sinuosity, and curve forward on the 

ventrolateral shoulder, where they rise into prominent 

clavate tubercles oriented about 45° to the keel. Secondary ribs also curve forward on the ventrolateral 

shoulder, where some rise into low clavate tubercles that 

parallel the primary ones. 

Prionocyclus novimexicanus is common in the middle 

part of the late Turonian Turner Sandy Member of the 

Carlile Shale in the Black Hills area of western South 

Dakota. The species has not been identified with certainty from outcrops east of the Black Hills. However, 

specimens have been found in the glacial drift in Minnesota. In 1926, a piece of a phragmocone was found in 

the Twin City Brick Company's pit in west St. Paul 

(USGS 13739). Recently, David Jones, Worthington, 

Minn., kindly showed me a very good specimen of P. 

novimexicanus in a septarian limestone concretion that 

was found in a streambed at Russell, Lyon County, by 

Timothy D. Holt of Marshall, Minn. 

An ammonite listed as Prionocyclus wyomingensis 

Meek was recorded by Wilder (1900, p. 113) from the 

Carlile Shale south of Hawarden, in Sioux County in the 

northwestern part of Iowa. If that identification is correct, rocks nearly of the age of P. novimexicanus crop out 

along the Missouri River in the Sioux City area. 
20 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

BELEMNITE 

Family BELEMNITELLIDAE Pavlov, 1914 

Genus ACTINOCAMAX Miller, 1823 

Actinocamax sp. 

Plate 7, figures 6, 7 

of the Carlile Shale and in the equivalent part of the 

Frontier Formation in central Wyoming (fig. 5). Belemnites have not been found in the rest of the Carlile Shale 

or in the underlying Greenhorn Formation. 

Fragments of belemnites that may be Actinocamax 

manitobensis (Whiteaves, 1889, p. 189, pl. 26, figs. 3, 3a, 

3b) are locally abundant in the hard concretionary 

limestone that rests on Precambrian granite in the 

Dakota Granite Company's quarry east of Milbank, in 

the SW1/4 sec. 18, T. 120 N., R. 47 W., Grant County, S. 

Dak. (USGS D10415). The fragments are associated with 

Collignoniceras woollgari regulare (Haas). In the 

northern part of the Western Interior of the United 

States, Actinocamax manitobensis has been found only 

in the zone of Collignoniceras woollgari in the basal part 

The lectotype of A. manitobensis may be from glacial 

drift along the Assiniboine River valley in southern 

Manitoba, Canada (Jeletzky, 1950, p. 4). Other 

specimens, however, have been found in the Assiniboine 

Member of the Favel Formation at outcrops along the 

Assiniboine River near Treherne, Manitoba (fig. 5). 

Jeletzky (1950) described and illustrated many excellent 

specimens of A. manitobensis and its varieties from the 

Treherne area. Collignoniceras woollgari occurs in the 

upper part of the underlying Keld Member of the Fa vel 

Formation. 

Belemnites, recorded as Belemnitella, have been 

found in the glacial drift in northeastern Iowa at Lime 

___ A L BE R T A / SA S KAT C HE wAN 1

1 ~Treherne jl '\ ------L__ CANADA MANITOBA \ ONTARIO uNiTEo-5TATEsl ____ ------~-- ~'-'~ 

I : n ... \../""" '--

XX I Grand Forks~ 

I ' 

I 

NORTH DAKOTA 1 

'-; MONTANA I BISMARCK \ 0 

I X I \ 

f I I MINNESOTA /" 

1.../( Billings0 ~--------------; 1 ) -- I Milbank~ Minneapoliso !WISCONSIN 

\-J'~/~ -ia~y-------~ SOUTH DAKOTA \ '~ I I R o I '-, I O ffJ 1 apid City PIERRE I ;\ 

I X sag I ex ·Sioux Falls }- ---w:-:- 0 --- L1me 

W Y 0 M 1 N G Springs\ ~asper L____________ ) '- X I .......__- "-- I Sioux City •waterloo 

IDAHo 

-----~ ~ J<emmerer ~~ I ~ , IOWA ( 

I ~ 0oES MOINES r:: 

Coalville L___- CHEYENNE j_l N E 8 R A S K A Omaha'\ )~ o -~---------<2- , ro 

I --~ LINCOLN \-------w;;s~~ 3 

UTAH 

----------

I I \ \ -1 I oDENVER r--------------...J-2 \-

I TOPEKA \-..J<.ansas City 

I ' 

I 

I XX 0 r I I JEFFERSON x KANSAS I CITY 

I \ I I MISSOURI 

COLORADO 

I I 

------- -'----- -------- 0 1 00 200 300 400 500 KILOMETERS 

FIGURE 5.-Map of part of the Western Interior showing localities (x) where Actinocamax manitobensis (Whiteaves) has been collected, and 

localities (•) where Actinocamax has been found in glacial drift. 
MOLLUSCAN RECORD, NORTHEASTERN UPPER CRETACEOUS SEAWAY 21 

Springs, Howard County, and near Waterloo, Black 

Hawk County (White, 1873a, p. 188; 1873b, p. 67). A 

specimen was also found in the glacial drift farther 

southeast near Warsaw, Ill. (Worthen, 1890, p. 5 and text 

fig. 4 on p. 4). The Waterloo specimen was later identified as A. manitobensis by Jeletzky (1950, p. 21). The 

other specimens are probably Actinocamax, and quite 

likely A. manitobensis, inasmuch as this is the most 

common belemnite in the Western Interior. 

Figured specimens.-USNM 299171, 299172. 

REFERENCES CITED 

Bain, H. F., 1896, Geology of Woodbury County: Iowa Geological 

Survey, v. 5, Annual Report 1895, p. 241-299. 

Bergquist, H. R., 1944, Cretaceous of the Mesabi iron range, Minnesota: Journal of Paleontology, v. 18, no. 1, p. 1-30, pls. 1-11. 

Bolin, E. J., 1956, Upper Cretaceous foraminifera, ostracoda, and 

radiolaria from Minnesota: Journal of Paleontology, v. 30, no. 2, 

p. 278-298. 

Cobban, W. A., 1951 [1952], Scaphitoid cephalopods of the Colorado 

group: U.S. Geological Survey Professional Paper 239, 42 p., 21 

pls. 

__ 1955, Some guide fossils from the Colorado shale and Telegraph 

Creek formation, northwestern Montana, in Billings Geological 

Society Guidebook 6th Annual Field Conference, Sweetgrass 

arch-Disturbed belt, Montana, 1955: p. 198--207, pls. 1-4. 

__ 1969, The Late Cretaceous ammonites Scaphites leei Reeside 

and Scaphites hippocrepis (DeKay) in the Western Interior of the 

United States: U.S. Geological Survey Professional Paper 619, 29 

p., 5 pls. 

Cobban, W. A., Erdmann, C. E., Lemke, R. W., and Maughan, E. K., 

1976, Type sections and stratigraphy of the members of the 

Blackleaf and Marias River Formations (Cretaceous) of the 

Sweetgrass arch, Montana: U.S. Geological Survey Professional 

Paper 974, 66 p., illus. 

Cobban, W. A., and Gryc, George, 1961, Ammonites from the Seabee 

formation (Cretaceous) of northern Alaska: Journal of Paleontology, v. 35, no. 1, p. 176-190, pls. 37, 38. 

Cobban, W. A., and Hook, S.C., 1979 [1980], Collignoniceras woollgari 

woollgari (Mantell) ammonite fauna from Upper Cretaceous of 

Western Interior, United States: New Mexico Bureau of Mines 

and Mineral Resources Memoir 37, 51 p., 12 pls. 

Cobban, W. A., and Scott, G. R., 1972, Stratigraphy and ammonite 

fauna of the Graneros Shale and Greenhorn Limestone near 

Pueblo, Colorado: U.S. Geological Survey Professional Paper 

645, 108 p., 41 pls. 

Condra, G. E., 1908, Geology and water resources of a portion of the 

Missouri River in northeastern Nebraska: U.S. Geological Survey 

Water-Supply Paper 215, 59 p. 

Conrad, T. A., 1860, Descriptions of new species of Cretaceous and 

Eocene fossils of Mississippi and Alabama: Academy of Natural 

Sciences of Philadelphia Journal, 2d ser., v. 4, p. 275-298. 

Cragin, F. W., 1893, A contribution to the invertebrate paleontology of 

the Texas Cretaceous: Texas Geological Survey 4th Annual 

Report, pt. 2, p. 139-246, pls. 24-46. 

Darton, N. H., 1905, Preliminary report on the geology and underground water resources of the central Great Plains: U.S. 

Geological Survey Professional Paper 32, 433 p. 

___ 1909, Geology and underground waters of South Dakota: U.S. 

Geological Survey Water-Supply Paper 227, 156 p. 

Geotimes, 1963, U. of Minnesota, Duluth, unveils new geological exhibits: v. 7, no. 7, p. 14-15. · 

Gill, J. R., and Cobban, W. A., 1965, Stratigraphy of the Pierre Shale, 

Valley City and Pembina Mountain areas, North Dakota: U.S. 

Geological Survey Professional Paper 392-A, 20 p. 

Haas, Otto, 1946, Intraspecific variation in, and ontogeny of, 

Prionotropis woollgari and Prionocyclus wyomingensis: 

American Museum of Natural History Bulletin, v. 86, art. 4, p. 

141-224, pls. 11-24. 

___ 1951, Supplementary notes on the ammonite genus 

Dunueganoceras: American Museum Novitates No. 1490, 21 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. 

Hattin, D. E., 1962, Stratigraphy of the Carlile Shale (Upper 

Cretaceous) in Kansas: Kansas Geological Survey Bulletin 156, 

155 p., 27 pls. 

__ 1975, Stratigraphic study of the Carlile-Niobrara (Upper 

Cretaceous) unconformity in Kansas and northeastern Nebraska: 

Geological Association of Canada Special Paper 13, p. 195-210. 

Hayden, F. V., 1873, First, second, and third annual reports of the 

United States Geological Survey of the Territories for the years 

1867, 1868, and 1869 [Reprints]: 261 p. 

Henderson, Junius, 1935, Fossil non-marine Mollusca of North 

America: Geological Society of America Special Papers No.3, 313 

p. 

Hyatt, Alpheus, 1903, Pseudoceratites of the Cretaceous, edited by T. 

W. Stanton: U.S. Geological Survey Monograph 44, 351 p., 47 

pls. 

Jeletzky, J. A., 1950, Actinocamax from the Upper Cretaceous of 

Manitoba: Geological Survey of Canada Bulletin 15, p. 1-27, 

36-41, pls. 1-3. 

Juignet, Pierre, Kennedy, W. J., and Wright, C. W., 1973, La limite 

Cenomanien-Turonien dans la region du Mans (Sarthe); 

Stratigraphie et paleontologie: Annales de Paleontologie, v. 59, 

pt. 2, p. 209-242, 3 pls. 

Kloos, J. H., 1872, A Cretaceous basin in the Sauk Valley, Minnesota: 

American Journal of Science, 3d ser., v. 3, p. 17-26. 

Logan, W. N., 1898, The invertebrates of the Benton, Niobrara, and 

Fort Pierre Groups: Kansas University Geological Survey, v. 4, 

pt. 8, p. 431-518, pls. 86-120. 

Mantell, Gideon, 1822, The fossils of the South Downs, or illustrations 

of the geology of Sussex: .London, Lupton Relfe, 327 p., 42 pls. 

Marcou, Jules, 1867, Le terrain cretace des environs de Sioux-City, de 

la Mission des Omahas et de Tekama, sur les bords du Missouri: 

Societe Geologique de France Bulletin; 2d ser., v. 24, p., 56-71. 

Matsumoto, Tatsuro, 1959, Upper Cretaceous ammonites of California, Part 2: Kyushu University, Memoirs of the Faculty of 

Science, Ser. D, Geology, Special Volume 1, 172 p., 41 pls. 

__ 1965, A monograph of the Collignoniceratidae from Hokkaido, 

Part 1: Kyushu University, Memoirs of the Faculty of Science, 

Series D, Geology, v. 16, no. 1, 80 p., 18 pls. 

Meek, F. B., 1871, Preliminary paleontological report, consisting of 

lists of fossils, with descriptions of some new types, etc.: U.S. 

Geological Survey of Wyoming (Hayden), Preliminary Report [v. 

4], p. 287-318. 

__ 1873, Preliminary paleontological report, consisting of lists and 

descriptions of fossils, with remarks on the ages of the rocks in 

which they were found, etc.: U.S. Geological Survey of the Territories (Hayden), Sixth Annual Report, p. 429-518. 

___ 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 pls. 
22 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

Meek, F. B., and Hayden, F. V., 1857, Description of new Species and 

GeneraofFossils, collected by Dr. F. V. Hayden in Nebraska Territory, under the direction of Lieut. G. K. Warren, U.S. 

Topographical Engineer; with some remarks on the Tertiary and 

Cretaceous formations of the north-west, and the parallelism of 

the latter with those of other portions of the United States and 

Territories: Proceedings of the Academy of Natural Sciences of 

Philadelphia, v. 9, p. 117-148. 

___ 1860, Descriptions of new organic remains from the Tertiary, 

Cretaceous and Jurassic rocks of Nebraska: Academy of Natural 

Sciences of Philadelphia Proceedings, v. 12, p. 175-185. 

Miller, H. W., 1968, Invertebrate fauna and environment of deposition 

of the Niobrara Formation (Cretaceous) of Kansas: Fort Hays 

Studies, n. ser., Science Ser., no. 8, 90 p., 9 pls. 

Moore, R. C., 1958, Introduction to historical geology (2d ed.): New 

York, McGraw-Hill, 656 p. 

Morrow, A. L., 1935, Cephalopods from the Upper Cretaceous of 

Kansas: Journal of Paleontology, v. 9, no. 6, p. 463-473, pls. 

49-53. 

Morton, S. G., 1842, Description of some new species of organic remains of the Cretaceous group of the United States, with a 

tabular view of the fossils hitherto discovered in this formation: 

Academy of Natural Sciences of Philadelphia Journal, v. 8, p. 

207-227, pls. 10, 11. 

Pergament, M. A. 1966, Zonal'naia stratigrafiia i inotseramy nizhnei 

chasti verkhnego mela Tikhookeanskogo poberezh'ia SSSR 

[Zonal stratigraphy and inocerams of the lowermost Upper 

Cretaceous of the Pacific coast of the USSR]: Geological Institute 

of the Academy of Sciences of USSR Transactions, v. 146, 83 p., 

36 pls. 

Peterson, Fred, and Waldrop, H. A., 1965, Jurassic and Cretaceous 

stratigraphy of south-central Kaiparowits Plateau, Utah, in 

Geology and resources of south-central Utah-Resources for 

power: Utah Geological Society and Intermountain Association 

of Petroleum Geologists Guidebook to the geology of Utah, no. 19, 

p. 47-69. 

Reagan, A. B., 1924, Cretacic Mollusca of Pacific slope: Pan-American 

Geologist, v. 41, p. 179-190, pls. 18-21. 

Reeside, J. B., Jr., 1927, Cephalopods from the lower part of the Cody 

shale of Oregon Basin, Wyoming: U.S. Geological Survey Professional Paper 150-A, p. 1-19, pls. 1-8. 

Rodis, H. G., 1961, Availability of ground water in Lyon County, Minnesota: U.S. Geological Survey Circular 444, 7p. 

___ 1963, Geology and occurrence of ground water in Lyon County, 

Minnesota: U.S. Geological Survey Water-Supply Paper 1619-N, 

41 p. 

Scott, G. R., and Cobban, W. A., 1964, Stratigraphy of the Niobrara 

Formation at Pueblo, Colorado: U.S. Geological Survey Professional Paper 454-L, p. Ll-L30, 11 pls. 

Shurr, G. W., 1979, Upper Cretaceous rocks at Lake Traverse in 

western Minnesota: U.S. Geological Survey Open-File Report 

79-379. 

Sloan, R. E., 1964, The Cretaceous System in Minnesota: Minnesota 

Geological Survey Report of Investigations 5, 64 p. 

Stanton, T. W., 1893 [1894], The Colorado formation and its invertebrate fauna: U.S. Geological Survey Bulletin 106, 288 p., 45 

pls. 

Stauffer, C. R., and Thiel, G. A., 1941, The Paleozoic and related rocks 

of southeastern Minnesota: Minnesota Geological Survey Bulletin 29, 261 p. 

Stephenson, L. W., 1952 [1953], Larger invertebrate fossils of the 

Woodbine formation (Cenomanian) of Texas: U.S. Geological 

Survey Professional Paper 242, p. 1-211, pls. 1-58. 

Todd, J. E., 1903, Description of the Mitchell quadrangle [South 

Dakota]: U.S. Geological Survey Geologic Atlas, Folio 99, 7 p. 

___ 1904, Benton formation in eastern South Dakota: Geological 

Society of America Bulletin, v. 15, p. 569-575. 

___ 1908, Description of the Elk Point quadrangle, South 

Dakota-Nebraska-Iowa: U.S. Geological Survey Geologic Atlas, 

Folio 156, 8 p. 

__ 1909, Description of the Aberdeen-Redfield district [South 

Dakota]: U.S. Geological Survey Geologic Atlas, Folio 165, 13 p. 

Upham, Warren, 1888, The geology of Crow Wing and Morrison Counties, in N. H. Winchell, The geology of Minnesota, v. 2, of the 

final report: Geological and Natural Survey of Minnesota, p. 

580-611. 

Warren, P. S., 1930a, New species of fossils from Smoky River and 

Dunvegan formations, Alberta: Research Council of Alberta 

Geological Survey Report 21, p. 57-68, pls. 3-7. 

___ l930b, Three new ammonites from the Cretaceous of Alberta: 

Royal Society of Canada Transactions, 3d ser., v. 24, sec. 4, p. 

21-26, 4 pls. 

___ 1947, Cretaceous Fossil Horizons in the Mackensie River Valley 

[Canada]: Journal of Paleontology, v. 21, no. 2, p. 118-123, pls. 

29, 30. 

Warren, P. S., and Stelck, C. R., 1955, New Cenomanian ammonites 

from Alberta: Research Council of Alberta Report No. 70, p. 

63-75, pls. 4-9. 

White, C. A., 1873a, On the eastern limit of Cretaceous deposits in 

Iowa: American AssoCiation for the Advancement of Science 

Proceedings, v. 21, p. 187-192. 

___ l873b, The easterp limit of Cretaceous deposits in Iowa: 

American Journal of Science, 3d ser., v. 5, no. 25, p. 66--69. 

___ 1883, A review of the non-marine fossil Mollusca of North 

America: U.S. Geological Survey Annual Report 3, p. 403-550, 28 

pls. 

___ 1894, Notes on the invertebrate fauna of the Dakota formation, 

with descriptions of new molluscan forms: United States 

National Museum Proceedings, v. 17, no. 995, p. 131-138, pl. 8. 

Whiteaves, J. F., 1889, On some Cretaceous fossils from British Columbia, the Northwest Territory, and Manitoba: Geological Survey 

of Canada, Contributions to Canadian Palaeontology, v. 1, p. 

151-196, pis. 20-26. 

Whitfield, R. P., 1885, Brachiopoda and Lamellibranchiata of the 

Raritan clays and Greensand marls of New Jersey: U.S. Geological Survey Monograph 9, 251 p., 35 pls. 

Wilder, F. A., 1900, Geology of Lyon and Sioux Counties: Iowa 

Geological Survey, v. 10, Annual Report 1899, p. 85-155. 

Winchell, N. H., 1874, The geological and natural history survey of 

Minnesota; the second annual report for the year 1873, in University of Minnesota Annual Report for 1873: p. 73-219. 

Winchell, H. V., 1893, Note on Cretaceous in northern Minnesota: The 

American Geologist, v. 12, no. 4, p. 220-223. 

___ 1895, Other Cretaceous fossils in Minnesota in Minnesota 

Geological Survey Final Report, v. 3, pt. 1, p. 53, 54. 

Woods, Henry, 1912, A monograph of the Cretaceous Lametlibranchia 

of England; v. 2, pt. 8: Palaeontographical Society Monograph, v. 

65, p. 285-340, pis. 51-54. 

Worthen, A. H., 1890, Drift deposits of lllinois: Geological Survey of Illinois, v. 8, p. 1-24. 

Wosick, F. D., 1977, Stratigraphy and paleontology of the Upper 

Cretaceous Morden Member (Vermilion River Formation) in the 

outcrop area, northeastern North Dakota: North Dakota University Master's thesis, 152 p. 

Wright, C. W., and Wright, E. V., 1951, A survey of the fossil 

Cephalopoda of the Chalk of Great Britain: Palaeontographical 

Society [Monograph], 40 p. 

Wright, C. W., and Matsumoto, Tatsuro, 1954, Some doubtful 

Cretaceous ammonite genera from Japan and Saghalien: Kyushu 

University, Memoirs of the Faculty of Science, Series D, Geology, 

v. 4, no. 2, p. 107-134, pls. 7, 8. 
A Page 

Acanthoceras adkinsi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

amphibolum .................................................. 4 

coloradoensis ............................................... 15 

ClUJpidum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

hazzardi ........................................................ 4 

tarrantense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

nitidum ................................................. 11 

wintoni ....................................................... 11 

sp ........................................................... 5, 13 

Acanthoceratidae . .. . . . . . .. . ...................... .. . . . . . . . . . . . . . 12 

Acknowledgments ................................................. 3 

Actinocamax manitoben.sis ............................. 17, 20 

sp ................................................. 16, 20; pl. 7 

Age, Campanian .................................................. 1 

Cenomanian . . . . . . . . . . . . . . . . . . . 1, 4, 5, 7 

Santonian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Turonian ....................................................... 5 

See also individual names. 

Alberta, Canada ............................................. 8, 13 

Ambonicardia cookii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Ammonites .......................................................... 8 

Ammonites novi-mexicani ................................... 19 

peracutlUJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

percarinatus ..................................... 17, 18, 19 

[Subprionocyclus} percarina.tus ....................... 1 

vermilionensis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

woollgari ................................................ 16, 19 

Ampakabites collignoni ....................................... 15 

Amphidonte sp. . .................................................. 7 

Anatimya plicata ........................................ 8; pl. 4 

Aowa Creek ...................................................... 19 

apicalis, lnoceramlUJ ............................. 5; pis. 2, 8 

Araucariacites ..................................................... 4 

Arcturus mine .............................................. pl. 14 

Assiniboine Member, Favel Formation ................. 20 

Assiniboine River valley, Canada ........................ 20 

B 

Raculites mariasensis ......................................... 10 

yokoyamai ......................................... 16; pl. 14 

barbouri, Unio ........................................... 8; pl. 4 

Belemnite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Relernnitella ................................................. 16, 20 

Belemnitellidae ....... ·............................................ 20 

Belle Fourche Shale ........................................... 16 

Bellingham, Minn ................................................. 6 

Bennett open-pit mine, Minn. . ..................... 5; pl. 2 

bergquisti, Metoicoceras ........... 14; pis. 8, 12, 13, 14 

Big Sioux River ............................................ 6, 19 

Bighorn County, Mont. ........................................ 9 

Rinneyites ca-rlilerUJis . .. ........ ... . . . . .... .. . ... . . .. 16; pl. 5 

Bivalves .............................................................. 3 

Black Hills, S. Oak .................................. 9, I6,· I9 

Blue Hill Member, Carlile Shale .................... I6, 18 

Bridge Creek Limestone Member, Greenhorn Formation, 

6, 15, I8 

Brule Creek, S. Dak. . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 6, 18 

INDEX 

c Page 

Calumet, Minn ............................................... 5, 11 

Camden State Park, Minn .................................... 9 

Campanian age, Pierre Shale ................................ 1 

Carlile Member, Cody Shale ................................. 9 

Carlile Shale ....... I, 3, 4, 5, 6, 9, IO, I2, 16, 17, 18 

basal ........................................................... 20 

Blue Hill Member . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . I6 

lower .......................................................... I9 

Turner Sandy Member ................................. I9 

carlilen.se, Tragodesmoceras ................................ I6 

carlilensis, Binneyites ............................... I6; pl. 5 

Cenomanian age, Dunveganoceras ...................... 4, 5 

early, Inoceramus .......................................... 5 

Margaritifera .................................. 7; pl. 4 

Plesiacanthocera.s ..................................... 4 

Unio .............................................. 8; pl. 4 

middle, Metengonocera.s ................................ 11 

late ............................................................... I 

Dunveganoceras . . .. . . . . . . . .. . . . . . . . .. . . . . . . . .. . I2, I3 

Inoceramus ....................................... 5, I9 

Metoicoceras .......................................... 14 

Proplacenticeras . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . I2 

Scaphites ................................................. 9 

Subprionocyclus ..................................... 19 

Chadron arch, Subprionocyclus percarinatus ........ I9 

Choffaticeras pavillieri ......................................... 6 

Coleraine, Minn., Metengonoceras dumbli .. ........... 11 

Coleraine Formation ................................ 11, I3, I4 

basal ............................................................. 5 

Collignoniceras vermilionense ..................... I7; pl. 5 

woollgari .......................................... 18, 19, 20 

intermedia ............................................. I6 

regulare .. . .. . . . . . . . ... . 5, I2, 16, I9, 20; pl. I5 

regularis ........... ... . . . . . . . . . . . . . . . . . . . . . . .. . ..... ... 16 

woollgari ............................................... I6 

Collignoniceratidae . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . 16 

Colorado, southeastern, Volviceramus invo/.utus ...... 7 

coloradoense, Watinoceras ......................... I5; pl. I5 

Coniacian, early ............................................. 9, IO 

late ............................................................... 7 

corvensis Scaphites . . . . . . . . . . . . . . . . . . . 9; pl. 5 

Cremnoceramus, deformis . . . . . . . . . . . . . . . . . . 10 

cuvieri, Inoceramus ....................... 6 

Cytherea orbiculata . . . . . . . . . . . . . . . . . . . . . . 18 

tenuis .............................. I8 

D 

Dakota City, Nebr ........................................... 4, 7 

Dakota Formation .................................. 1, 7, 8, I9 

Dakota Granite Company quarry. 5, 9, 11, I2, 16, 20 

Dakota Sandstone . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . I 

Delano quarry, Minn ............................................ 7 

delicatu.lus sloani, Scaphites ........................ 8; pl. 5 

Discinisca ( Discaradisca) .................. • .................... 7 

dumbli, Metengonoceras .................... 11; pis. 6, 7, 8 

Dunvegan, Canada . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I3 

Dunvegan Creek, Canada . ................... .. . . .. . . . . . . .. . 13 

Dunveganoceras hagei ......... 3, 5, I3; pis. IO, 11, 12 

pondi ............. I, 3, 11, 12, 13; pis. 6, 9, 10, 15 

E Page 

Eagle Ford Shale . . . . . . . . . . . . . . .. . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . 11 

Elmspring, S. Dak. . . . . . .. . .. . . . . .......................... .... I6 

Engonoceratidae ............ .. . ............ ......... ..... ... . . . . . I1 

F:pengorwceras dumblei . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . 11 

[Metengonocera.s} dumbli ................................ 5 

F: quisetosporites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Escalante, Utah ................................................... 6 

F 

Fagesia sp. ......... .. . . ...... ... ............. .. ...... ... ...... ... 15 

Fairbury, Nebr .................................................... 8 

Fa vel Formation, Assiniboine Member ................. 20 

Keld Member .............................................. 20 

Foresteria (Texa.sia) dentatocarinatum ................... 9 

Formations, Belle Fourche Shale .... . . . . . .... .. . ......... 16 

Carlile Shale .......... 1, 4, 5, 6, 9, 12, 16, I7, 18 

basal ..................................................... 20 

Blue Hill Member .. .. . . .............. ... ... . .. . .. .. I8 

lower .................................................... 19 

Turner Sandy Member ........................... 19 

uppermost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . 10 

Cody Shale, Carlile Member ........................... 9 

Coleraine ............................................ 5, 11, 13 

basal ..................................................... 14 

Dakota ............................................ I, 7, 8, I9 

Eagle Ford Shale . . . . . . . ... . . . . . . . ............ .. . . . ...... 11 

Favel Formation .......................................... 20 

"Fort Benton" . . . . ... . ..... ... . . . . . ........ .. . .. . . . . . . ..... 19 

Fox Hills ...................................................... I 

Frontier .............................................. 5, 9, 20 

Graneros Shale ............................ I, 3, 4, 5, I9 

basal ................................................ 11, I2 

Greenhorn ............................. 3, 4, 5, 6, I5, I9 

Bridge Creek Member . . . . . . . . . . . . . . . . . . . . . . . . . . . . I8 

upper part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . 19 

Marias River Shale, Kevin Member .. . .. . . .. ..... IO 

Middle Chalk ....................................... 5, 6, 16 

Niobrara ................................................... I, 7 

Smoky Hill Shale Member ........................ 7 

Pierre Shale ............................................ I, I2 

Raritan ......................................................... 8 

Seabee .......................................................... 8 

Smoky River Shale ........................................ 8 

Straight Cliffs ................................................ 6 

Tropic Shale ................................................ 12 

Windrow ................................................ pl. I4 

Woodbine ................................................ 4, 11 

Templeton Member .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

"Fort Benton" Formation .................................... I9 

Fort Benton limestone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 

Fox Hills Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I 

(ragilis, Inoceramus .................................... 3; pl. 1 

Frontier Formation .................................... 5, 9, 20 

G 

Ghent, Minn., Scaphites preventricosus . . .... .. . . . . . . . . 10 

t]interensis, Inoceramus ............................... 5; pl. 2 

Golden Bluff Vineyards, Collignonicera.s woollgari 

regulare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

23 
24 

Page 

Graneros Shale .................................. 1, 3, 4, 5, 19 

basal ...................................................... 11, 12 

uppennost ..................................................... 4 

Greenhorn Fonnation ............. 3, 4, 5, 6, 15, 18, 19 

Granite Falls, Minn., Inoceramus howelli .............. 6 

Grayson County, Texas ........................................ 4 

H 

hagei, Dunveganoceras ............ 3, 13; pis. 10, 11, 12 

Hartland Shale Member, Greenhorn Fonnation ....... 5 

Hawarden, Iowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

Hill Annex mine ....................................... 5; pl. 14 

howelli, Inoceramus .................................... 6; pl. 2 

Inoceramidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

Inoceramus apical is . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5; pis. 2, 8 

barabina. See Mytiloides mytiloides. 

conradi ....................................................... 18 

cuvieri .................................................. 4, 6, 9 

erectus ........................................................ 10 

fragilis ................................... 3, 6, 9, 18; pl. 1 

mesabiensis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

frechi ............................................................ 9 

ginterensis ............................................ 5; pl. 2 

howelli ................................................. 6; pl. 2 

involutus. See Volviceramus involutus. 

labiatus. See Mytiloides mytiloides. 

lamarcki apical is ........................................... 5 

mesabiensis .......................................... 5; pl. 2 

platinus ........................................................ 7 

prefragilis prefragilis ...................................... 4 

stephensoni ................ 3, 4, 13, 19; pis. 2, 3 

problematicus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

waltersdorfensis ........................................... 10 

involutus, Volviceramus ............................ 7; pl. 15 

Ionia Volcano ...................................................... 3 

Iowa, glacial drift fossils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

northeastern ................................................ 16 

northwestern ....................................... 4, 6, 19 

Iowa Creek. See Aowa Creek. 

K,L 

Kamchatka, U.S.S.R ............................................ 5 

Kanab valley, Utah ............................................ 12 

Keewatin, Minn. . ................................................. 5 

Keld Member, Fa vel Fonnation . . . . . .. ....... ... ......... 20 

Kevin Member, Marias River Shale ... . . . . . . . . . ... . . . . . 10 

labiatus, Mytiloides ........................................ pl. 8 

Lake Traverse, Minn. . .............................. 6, 15, 19 

Laternulidae ........................................................ 8 

Lewisville Member, Woodbine Fonnation ............... 4 

Lime Springs, Iowa ...................................... 16, 20 

Lincoln Limestone Member, Greenhorn Fonnation .. 4 

Lower Potatoe Valley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

M 

Mackenzie River, Canada, Scaphites delicatulus ..... 8 

Mammites bellsanus, synonym .............................. 4 

nodosoides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Manitoba, Canada . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

manitobensis Acti1wcamax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Margaritana ........................................................ 7 

Margaritifera nebrascensis ....................... 7, 8; pl. 4 

Margaritiferidae ................................................... 7 

Marias River Shale .. . . ... . ............. ... .... ... ............. 10 

mariasensis, Scaphites .. ............ ... . . . . .. ... . . . . .......... 10 

Marshall, Minn., Proplacenticeras pseudoplacenta . 12 

Mesabi Range ............................ 1, 3, 5, 11, 13, 14 

mesabiensis, Inoceramus ............................. 5; pl. 2 

Metacalyoceras sp .......................................... 5, 13 

Metengonoceras dumbli ...... 3, 4, 11, 13; pis. 6, 7, 8 

INDEX 

Page 

Metoicoceras bergquisti ........ 5, 14; pis. 8, 12, 13, 14 

crassicostae ................................................... 4 

gesliniatum . . ....... ... .................. ... . .. . ............ 15 

gibbosum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

kanabense ................................................... 15 

latoventer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

swallovii ............................................. 4, 5, 14 

whitei ......................................................... 15 

Middle Chalk, England ............................... 5, 6, 16 

Milbank, S. Dak ....................... 5, 9, 11, 12, 16, 20 

Minneapolis, Minn .............................................. 19 

Minnesota, glacial drift fossils ........................... 1, 3 

Missouri River ................................ 1, 6, 17, 18, 19 

Mitchell, S. Dak. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 18 

Montana .......................................................... 5, 7 

Mortoniceras vermilionense ................................. 17 

Mytiloides s.l. . ........................................... 6; pl. 1 

duplicostatus ·............................................... 15 

labiatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pl. 8 

mytiloides ................................. 6, 19; pis. 1, 8 

mytiloides, Mytiloides ...................... 6, 19; pis. 1, 8 

N,O 

nebrascensis, Margaritijera .......................... 7; pl. 4 

Nebraska, northeastern ................................. 4, 6, 7 

Neoptychites cephalotus ...................................... 15 

xetriformis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . 15 

Niobrara Fonnation .......................................... 1, 7 

North Dakota, eastern ............................ : ............ 7 

novimexicanus, Prionocyclus ............................... 19 

Ochs Brick and Tile Company claypit, Minn ... pl. 14 

Odessa, Minn., Mytiloides mytiloides ..................... 7 

Ortonville, Minn., Mytiloides mytiloides ................. 6 

Ostrea sp ............................................................ 7 

Otoscaphites seabeensis .............................. 11; pl. 5 

p 

patulus, Scaphites ....................................... 9; pl. 

Peace River, Canada, Scaphites delicatulus ........... 8 

Pectunculus [Satwarca] siouxensis . . . . . . . . . . . . . . . . . . . . . . . . 1 

Pembina River, N. Dak. .................................... 10 

percarinatus, Ammonites {Subprionocyclus] ........... 1 

Subprionocyclus ................... 1, 18; pis. 1, 5, 15 

Pierre Shale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 12 

Placenticeras placenta ................................... 11, 12 

(Sphenodiscus) sp. undet. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 11 

stantoni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Placenticeratidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

platinus Platyceramus ...................................... 1, 

plicata, Anatimya ....................................... 8; pl. 4 

Platyceramus platinus ...................................... 1, 7 

Plesiacanthoceras wyomingense . . . . . . . . .. . . . . . . . . . . . . . 4, 16 

Plymouth County, Iowa ........................................ 4 

Pollen, bisaccate conifer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Ponca State Park, Nebr ....................................... 4 

pondi, Dunveganoceras ......... 1, 12; pis. 6, 9, 10, 15 

Powder River basin ............................................. 5 

prefragilis prefragilis, Inoceramus ......................... 4 

prefragilis stephensoni, Inoceramus .... : .................. 4 

preventricosus, Scaphites ........................... 10; pl. 8 

Prionocyclus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

hyatti ...................................................... 6, 16 

novimexicanus . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. 19 

(Prionotropis) woolgari ................................. 18 

woollgari ............................................... 16 

quadratus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

woolgari ...................................................... 19 

wyomingensis .............................................. 19 

elegans .................................................. 19 

sp ............................................................... 13 

Prionotropis vermilionensis ................................. 17 

woolgari ................................................. 16, 19 

woollgari ................................................ 16, 18 

Pristinuspollenites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Page 

Proplacenticeras pseudoplacaenta ........... 11, 16; pl. 7 

stantoni ........................................ 12, 16; pl. 7 

Pseudopenw congesta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

pseudoplacenta, Proplacenticeras ................ 11; pl. 7 

Pterospermopsis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Pueblo, Colo. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6, 15 

Puebloites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 15 

R 

Raritan Fonnation ............................................... 8 

Redfield, S. Dak., Prionotropis woolgari ............. 17 

Redwood County, Minn ...................................... 19 

References cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

regulare, Collignoniceras woollgari ............ 16; pl. 15 

Richmond, S. Dak. . . . . ...... ....... ........ .... .. . ... . . ....... 16 

Riverside, Iowa, claypit ............................. 4, 11, 12 

Russell, Minn. . .............................................. 9, 19 

s 

Sage Breaks Member, Carlile Shale .................... 10 

St. James, Nebr., Volviceramu.s involutus ............. 7 

St. Paul, Minn. ............. .. . . ........ ....... .. ... ...... .. . . .. 19 

Sakhalin, U.S.S.R., Inoceramus ginterensis ............ 5 

Sanoarca siouxensis .................................. 1; pl. 14 

Santonian age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 7 

Sauk River valley ......... ... .. . . . . . ......... ... .. ........... .. 16 

Scaphites carlilensis ............................................ 1 0 

corvensis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9; pl. 5 

delicatulus greenhomen.sis .............................. 9 

sloani ............................... 8, 11, 16; pl. 15 

impendicostatus . . . ... . . ........... ........ ... . .. . . . ....... 10 

mariasensis . .. . . . . . ... . . . . . . .......... ... .. .......... ....... 10 

gracillistriatus ....................................... 10 

nigricollensis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

patulus ................................................ 9; pl. 1 

preventricosus ................................. 9, ·10; pl. 8 

sweetgrassensis ...................................... 10 

ventricosus zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Scaphitidae .......................................................... 8 

Schizosporis reticulatus ........................................ 4 

Sciponoceras gracile ....................................... 9, 12 

Seabee Fonnation ................................................ 8 

seabeensis, Otoscaphites ............................. 11; pl. 5 

Seaway, Cretaceous ............................................. 1 

Shark teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Sioux City, Iowa ................................ 1, 13, 16, 19 

Sioux City Brick and Tile Company claypit, Inoceramus 

prefragilis stephensoni ........................ 4 

Sioux Quartzite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Sioux River ......................................................... 1 

siouxensis, Sanoarca ................................. 1; pl. 14 

Pectunculus {Sanoarca] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

sloani, Scaphites delicatulus ........................ 8; pl. 5 

Smoky Hill Shale Member, Niobrara Fonnation . 7, 8 

South Dakota, southeastern .................... 1, 6, 7, 19 

Sphenodiscus dumbli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

Spores, trilete ..................................................... 4 

stantoni, Proplacenticeras . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

stephensoni, Inoceramus prefragilis ....................... 4 

Straight Cliffs Fonnation ...................................... 6 

Subpri01wcyclus percarinatus ....... 1, 3, 5, 9, 17, 18; 

pis. 1, 5, 15 

sweetgrassensis, Scaphites preventricosus .............. 10 

T 

Taxodiaceaepollenites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Templeton Member, Woodbine Fonnation ........ 4, 11 

Tetracolpites ........................................................ 4 

Tragodesmoceras carlilense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 

Treherne, Manitoba, Actinocamax manitoben.sis ... 20 

Tricolpites ........................................................... 4 

Tropic Shale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Turner Sandy Member, Carlile Shale .................. 19 
INDEX 25 

Page Page Page 

Turonian age ............................................... 3, 5, 6 Vermilion, Nebr .................................................. 9 Woodbine Formation ...... ... ..................... ... .. . . . . . .. 11 

early .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6, 9, 15 Vermilion River ................................................. 18 woollgari regulare, Collignoniceras ............... 16; pl. 15 

middle ............................ 3, 6, 9, 11, 12, 17, 19 vermilionen.sis, Ammonites ................................. 17 Wyoming, central, Frontier Formation ............. 9, 20 

upper .................................................. 5, 9, 10 Collignoniceras ................................... 17; pl. 5 

Twin City Brick Company .. . . .. ............. .. .. . . .. . . .. . . . 19 

Two River, Minn ............................................. 7, 8 

Vermillion, Nebr .................................................. 3 

Vermillion River ................................................ 17 Y,Z 

Volcano Hill, Nebr .............................. 3, 5, 17, 18 

U,V Volviceramus grandis ........................................... 7 

involutus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7; pl. 15 

Yell ow Medicine County Museum .......................... 6 

Yellow Medicine River ....................................... 10 

Unio, (Baphia) nebrascensis ................................. 7 

barbouri . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 8; pl. 4 

Union County State Park, S. Dak ................. 17, 18 

Unionidae ............................................................ 8 

Upper Chalk, England, Volviceramus involutus ..... 7 

w 

Warsaw, Illinois ............................................ 17, 21 

Waterloo, Iowa .............. .. . . . . . . . . . . . . . . . . . ........ ......... 21 

Watinoceras colomdoense .......................... 15; pl. 15 

yokoyamai, Baculites ............................... 16; pl. 14 

Zone, Collignoniceras woollgari ........................... 20 

Dunveganoceras alberten.se .............................. 5 

Prionocyclus hyatti .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 6 

Scaphites ventricosus ...................................... 7 

Vang, S. Dak., Scaphites mariasensis ................. 10 Western Interior Cretaceous seaway ..................... 1 Sciponoceras gracile Range ............................. 9 

Vascoceras (Greenhornoceras) birchbyi ................. 15 Windrow Formation ...................................... pl. 14 sub, Collig1wniceras woollgari regulare .......... 11 

PLATES 1-15 

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

Survey Photographic Library, Federal Center, Denver, Colorado 80225. 
PLATE 1 

[Figure 1 natural size; figure 2 slightly reduced] 

Turonian mollusks 

FIGURE 1. Mytiloides mytiloides (Mantell) s. 1. (p. 6). 

Latex cast of a slab of limestone from the Greenhorn Formation at USGS locality 

D10502 in the SE 1/4NWVt sec. 11, T. 31 N., R. 5 E., Dixon County, Nebr. USNM 

299137. 

2. Inoceramus fragilis Hall and Meek (p. 3). 

Several specimens (a) in part of a limestone concretion from the Carlile Shale at USGS 

locality 2989 in sec. 29, T. 32 N., R. 4 E., Dixon County, Nebr. Other fossils are (b) 

Scaphites patulus Cobban and (c) Subprionocyclus percarinatus (Hall and Meek). 

USNM 299138. 
PROFESSIONAL PAPER 1253 PLATE 1 

GEOLOGICAL SURVEY 

20mm 

2 

TURONIAN MOLLUSKS 
PLATE 2 

[All figures natural size] 

Turonian bivalves 

FIGURES 1-6, 9, 10. Inoceramus apicalis Woods (p. 5). 

1, 2. Left valve from USGS locality D10415 in the SW1/4 sec. 18, T. 120 

N., R. 47 W., Grant County, S. Dak. USNM 299139. 

3, 4. Another left valve from the same locality. USNM 299140. 

5, 6. Left valve from a limestone concretion in the Carlile Shale at 

Volcano Hill, USGS locality D10404 in sec. 3, T. 31 N., R. 5 E., 

Dixon County, Nebr. USNM 299141. 

9, 10. Left valve from the same locality as figures 1, 2. USNM 299142. 

13-16. Inoceramus howelli White (p. 6). 

From a large boulder of ferruginous sandstone in the glacial drift at 

Granite Falls, Minn. 

13, 14. Anterior view of both valves and view of right valve of UMIP 

9000a. 

15, 16. Anterior view of both valves and view of left valve of UMIP 

9000b. 

Cenomanian bivalves 

7, 8, 11, 12. Inoceramus mesabiensis Bergquist (p. 5). 

Anterior views of both valves and views of the right valves of two 

specimens from the Coleraine Formation at the Bennett mine (USGS 

locality 13766) of the Mesabi Range in theSE 1/4 sec. 13, T. 57 N., R. 22 

W., Itasca County, Minn. USNM 299143, 299144. 

17, 18. Inoceramus ginterensis Pergament (p. 5). 

From a limestone concretion in the upper part of the Graneros Shale at 

USGS locality D10503 in the W1!2W 1/2 sec. 15, T. 90 N., R. 48 W., 

Plymouth County, Iowa. 

17. Right valve. USNM 299145. 

18. Right valve. USNM 299146. 

19, 20. Inoceramus prefragilis stephensoni Kauffman and Powell (p. 4). 

From the lower part of the Graneros Shale at the Sioux City Brick 

and Tile Company's claypit in Riverside, Iowa. 

19. Right valve. YPM 14895. 

20. Left valve. YPM 14896. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 2 

2 4 6 7 

8 

11 12 

10 

16 

13 15 

CENOMANIAN AND TURONIAN BIVALVES 
PLATE 3 

[Figure natural size] 

Inoceramus prefragilis stephensoni Kauffman and Powell (p. 4). 

Large specimens from the basal part of the Graneros Shale in the Sioux City Brick and Tile Company's claypit in Riverside, Iowa. USNM 299147. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 3 

INOCERAMUS 
PLATE 4 

[All figures natural size] 

.FIGURES 1-4. Unio barbouri White (p. 8). 

From the Dakota Formation near the mouth of Two River in sec. 8, T. 127 N., R. 29 

W., Morrison County, Minn. 

1, 2. Lateral and dorsal views ofUMIP 4566a. 

3, 4. Dorsal and lateral views of UMIP 4566b. 

5. Anatimya plicata Bergquist (p. 8); 

View of right valve of a specimen from the Dakota Formation at the Ochs Brick and 

Tile Company's claypit in the NEVt sec. 26, T. 109 N., R. 35 W., Brown County, 

Minn. UMIP 9001. 

6-8. Margaritifera cf. M. nebrascensis (Meek) (p. 7). 

From the same locality as figures 1-4. Three views of UMIP 4567. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 4 

2 

3 

5 

7 8 

CENOMANIAN BIVALVES 
FIGURES 

PLATE 5 

[All figures natural size] 

Turonian ammonites 

1-3. Binneyites carlilensis Cobban (p. 16). 

From concretionary limestone at the base of the Cretaceous at USGS 

locality Dl0415 in the Dakota Granite Company's quarry in the SW'/4 

sec. 18, T. 120 N., R. 47 W., Grant County, S. Dak. 

1, 2. USNM 299148. 

3. USNM 299149. 

4, 5. Tragodesmoceras carlilense Cobban (p.ll) 

From the same locality as figures 1-3 (USGS loc. D10415). USNM 299150. 

6-11, 16, 17. Otoscaphites seabeensis Cobban and Gryc (p. 11). 

From the same locality as figures 1-3 (USGS loc. D10415). 

6-8. Side, top, and rear views of a small adult body chamber. 

USNM 299151. 

9. Side view of a broken body chamber. USNM 299152. 

10, 11. Rear and side views of USNM 299153. 

16, 17. Side and rear views of USNM 299154. 

12-15, 18-23. Scaphites delicatulus sloani Cobban, n. subsp. (p. 8). 

From the same locality as figures 1-3 (USGS loc. D10415). 

12-15. Top, rear, side, and front views of the holotype. USNM 

299155. 

18, 19. Views of a phragmocone showing rursiradiate ribbing. 

USNM 299156. 

20, 21. Front and side views ofUSNM 299157. 

22, 23. Side and rear views of USNM 299158. 

24, 25. Scaphites corvensis Cobban (p. 9). 

From some depth between 50 and 70 m in the Minnesota Department of 

Conservation's water well in the NE'14SE 1

/4 sec. 32, T. 111 N., R. 42 W., 

Lyon County, Minn. UMIP 8284. 

26-37. Subprionocyclus percarinatus (Hall and Meek) (p. 18). 

From the Carlile Shale at Volcano Hill, USGS locality D10404 in sec. 3, T. 

31 N ., R. 5 E., Dixon County, Nebr. 

26. Latex cast of a small specimen. USNM 299159. 

27, 28. USNM 299160. 

29. USNM 299161. 

30, 31. USNM 299162. 

32, 33. USNM 299163. 

34. Lectotype, from Hall and Meek, 1856, pL 4, fig. 2b. 

35. Imprint on gray shale. USNM 299164. 

36, 37. USNM 299165. 

38-42. Collignoniceras vermilionense (Meek and Hayden) (p. 17). 

38. Plaster cast of holotype, USNM 224. 

39, 40. Rear and side views of a small adult that has conspicuous 

siphonal clavi but lacks clearly defined ventrolateral 

tubercles. From a limestone concretion in the Carlile 

Shale at the same locality as figures 26-37 (USGS loc. 

Dl0404). USNM 299166. 

41, 42. Side and rear views of a small adult that has ventrolateral 

horns and a conspicuous keel, from the same locality as 

figures 26-37 (USGS loc. D10404). USNM 299167. 
GEOLOGICAL SURVEY 

2 3 4 5 

12 

13 

20 21 

22 

27 28 29 

32 34 

39 40 

14 

7 

6 8 

23 

24 

30 31 

35 

41 

TURONIAN AMMONITES 

PROFESSIONAL PAPER 1253 PLATE 5 

9 

10 11 

18 19 

25 

38 

42 
PLATE 6 

[Natural size) 

Slab of gray shale from near the base of the Graneros Shale at the Sioux City Brick and Tile Company's claypit, Riverside, Iowa, containing a crushed specimen of the smooth ammonite 

Metengonoceras dumbli (Cragin) (SCPM F259D) and above it the ornamented inner whorls of 

Dunveganoceras pondi Haas (SCPM F259C). 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 6 

DUNVEGANOCERAS AND METENGONOCERAS 
PLATE 7 

[All figures natural size] 

FIGURES 1, 2. Proplacenticeras stantoni (Hyatt) (p. 12). 

Front and side views of a phragmocone from concretionary limestone at the base of 

the Cretaceous at USGS locality D10415, in the Dakota Granite Company's 

quarry in the SW 1

/4 sec. 18, T. 120 N ., R. 47 W., Grant County, S. Dak. USNM 

299168. 

3-5. Proplacenticeras pseudoplacenta (Hyatt) (p. 11). 

3. A small phragmocone having falcoid ribs from the same locality as figures 1, 

2 (USGS loc. D10415). USNM 299169. 

4, 5. Side and rear views or' a phragmocone from the same locality. USNM 

299170. 

6, 7. Actinocamax sp. (p. 20). 

From the same locality as figures 1, 2. 

6. Broken specimen lying beside a piece offossil bone. USNM 299171. 

7. Another fragment split longitudinally. USNM 299172. 

8. Metengonoceras dumbli (Cragin) (p. 11). 

A crushed specimen of an adult that has part of the body chamber. From gray silty 

shale near base of Graneros Shale in the Sioux City Brick and Tile Company's 

claypit, Riverside, Iowa. SCPM F259B. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 7 

PROPLACENTICERAS, METENGONOCERAS, AND ACTINOCAMAX 
PLATE 8 

[All figures natural size] 

Cenomanian ammonite 

FIGURES 1-4. Metoicoceras bergquisti Cobban, n. sp. (p. 14). 

1, 2. Most of the body chamber of a small adult from the Coleraine 

Formation at the Hill Annex mine, Calumet, Minn. (USGS loc. 

13063). UMIP 9008. 

3, 4. Older part of a larger body chamber from the Coleraine Formation from 

the same locality as figures 1 and 2. (USGS 13063). USNM 299173. 

Turonian mollusks 

5, 6. Metengonoceras dumbli (Cragin) (p. 11). 

From the Coleraine Formation near Calumet, Minn. Collected by Blaine Conley, 

Swan River, Minn. USNM 299174. 

7. Mytiloides labiatus (Schlotheim) (p. 6). 

From sandy limestone, which fills a fissure in Precambrian granite, at USGS 

locality D10420 (Delano quarry), in the SE 1/4SE 1/4 sec. 16, T. 120 N., R. 45 W., 

Lac Qui Parle County, Minn. USNM 299175. 

8, 9. Mytiloides mytiloides (Mantell) (p. 6). 

8. A fragment from the same locality as figure 7. USNM 299176. 

9. Latex cast of another specimen from the same locality as figure 7. USNM 

299177. 

10. Inoceramus apicalis Woods (p. 10). 

Part of a right(?) valve from the same locality as figure 7. USNM 299178. 

Coniacian ammonite 

11-13. Scaphites preventricosus (Cobban) (p. 10). 

Found by Phyllis Regnier on farm 1.6 km north of Ghent, Lyon County, Minn. 

UMIP 9007. 
GEOLOGICAL URVEY PROFESSIONAL PAPE R 1253 PLATE 8 

CENOMANIAN, TURONIAN, AND CONIACIAN MOLLUSKS 
PLATE 9 

[Natural size] 

Dunueganoceras pondi Haas (p. 12). 

Side view of a partly crushed adult from the basal part of the Graneros Shale in the Sioux City 

Brick and Tile Company's claypit, Riverside, Iowa. An unnumbered specimen at the Sioux City 

Public Museum, Sioux City, Iowa. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 9 

DUNVEGANOCERAS 
PLATE 10 

[Figure 1 natural size; figure 2 about 0.6 natural size] 

FIGURE 1. Dunueganoceras pondi Haas (p. 12). 

Rear view of an adult body chamber from the basal part of the 

Graneros Shale in the Sioux City Brick and Tile Company's claypit, 

Riverside, Iowa. YPM 14897. 

2. Dunueganoceras hagei Warren and Stelck (p. 13). 

Rear view of the specimen shown on plate 11. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 10 

DUNVEGANOCERAS 
PLATE 11 

[About 0.6 natural size] 

Dunueganoceras hagei Warren and Stelck (p. 13). 

From the Coleraine Formation at the Hill Annex mine, Calumet, Minn. This 

specimen is at the Department of Geology, University of Minnesota, Duluth. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 11 

DUNVEGANOCERAS 
PLATE 12 

[All figures natural size] 

FIGURES 1-5. Metoicoceras bergquisti Cobban, n. sp. (p. 14). 

1-3. Ornamented variant from the Coleraine Formation at the 

Hill Annex mine, Calumet, Minn. The small specimen is 

part of the inner whorls. UMIP 6178. 

4, 5. Part of a phragmocone from the same locality as figures 

1-3. UMIP 9005a. 

6, 7. Dunueganoceras hagei Warren and Stelck (p. 13). 

Older part of an adult body chamber from the same locality as 

figures 1-5. UMIP 5058. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 

2 

3 

7 

METOICOCERAS AND DUNVEGANOCERAS 

5 

PLATE 12 
PLATE 13 

[Figures natural size] 

FIGURES 1, 2. Metoicoceras bergquisti Cobban, n. sp. (p. 14). 

Part of a very large adult body chamber from the basal part of the 

Coleraine Formation at the Hill Annex mine, Calumet, Minn. 

Paratype UMIP 9003. 
GEOLOGICAL SURVEY PROFESSIO AL PAPER 1253 PLATE 13 

METOICOCERAS 
PLATE 14 

[All figures natural size] 

Cenomanian ammonite 

FIGURES 1-5, 10-15. Metoicoceras bergquisti Cobban, n. sp. (p. 14). 

1-3. Holotype, the older part of a small adult body chamber from the 

basal part of the Coleraine Formation at the Arcturus mine, 

Marble, Minn. Figure 3 is a latex cast of the last inner whorl. 

UMIP 9004. 

4, 5. Part of a phragmocone from the basal part of the Coleraine 

Formation at the Hill Annex mine, Calumet, Minn. Paratype 

UMIP 9005b. 

10, 11. Part of a smooth phragmocone from USGS locality 13060, Arcturus 

mine, Marble, Minn. Paratype USNM 299182. 

12-15. Older two-thirds of an adult body chamber from the same locality 

as figures 4 and 5. Figures 12 and 13 are of a latex cast of part of 

the last inner whorl. Paratype UMIP 5061. 

Turonian ammonite 

6-8. Baculites yokoyamai Tokunaga and Shimizu (p. 16). 

From concretionary limestone at the base of the Cretaceous at USGS 

locality D10415 in the Dakota Granite Company's quarry in the SW'14 sec. 

18, T. 120 N., R. 47 W., Grant County, S. Dak. 

6, 7. Ventral and lateral views of a juvenile with most of its shell 

material. USNM 299179. 

8. Lateral view of part of a deformed phragmocone. USNM 299180. 

Cenomanian bivalve 

9. Sanoarca siouxensis (Hall and Meek) (p. 1). 

Latex cast of a right valve from the Windrow Formation (as used in 

Minnesota) at USGS locality D10507 in the Ochs Brick and Tile Company's claypit in the SE 1

/.tNE 1/.t sec. 26, T. 109 N., R. 35 W., Brown 

County, Minn. USNM 299181. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 14 

6 7 

10 

12 

CENOMANIAN AND TURONIAN MOLLUSKS 
PLATE 15 

[All figures natural size] 

Cenomanian ammonite 

FIGURE 1. Dunveganoceras pondi Haas (p. 12). 

Side view of part of a small phragmocone from a limestone concretion in the 

Graneros Shale at USGS locality D10412 in the SW1/4NWVJ sec. 4, T. 90 

N., R. 48 W., Plymouth County, Iowa. USNM 299183. 

Turonian ammonites 

2-4, 7-11. Collignoniceras woollgari regulare (Haas) (p. 16). 

2. Coarse-ribbed form from concretionary limestone at the base of the 

Cretaceous at USGS locality D10415 in the Dakota Granite Company's quarry in the SWVJ sec. 18, T. 120 N., R. 47 W., Grant 

County, S.Dak. USNM 299184. 

3, 4. Small specimens from the same locality as figure 2 showing dense 

even ribbing on early whorls. USNM 299185, 299186. 

7, 8. A larger specimen from the same locality as figure 2. USNM 299187. 

9. Fragment of an adult body chamber from the same locality as figure 

2. USNM 299188. 

10. Latex cast from the same locality as figure 2 showing parts of several 

whorls. USNM 299189. 

11. Sketch of part of a whorl found in the glacial drift near Warsaw, Ill. 

(from Worthen, 1890). 

5, 6. Subprionocyclus percarinatus (Hall and Meek)? (p. 19). 

Latex cast of a specimen in a clay ironstone concretion found in the glacial 

drift south of Minneapolis in the S 1

/2 sec. 13, T. 115 N., R. 21 W., Dakota 

County, Minn. UMIP 9006. 

12. Watinoceras coloradoense (Henderson) (p. 15). 

Float specimen from the Greenhorn Formation at USGS locality D10578 in 

the NE 1

/4SE 1/4 sec. 2, T. 125 N., R. 49 W., Traverse County, Minn. USNM 

299190. 

Coniacian bivalve 

13, 14. Volviceramus involutus (J. de C. Sowerby) (p. 7). 

Right valve encrusted with Pseudoperna congesta (Conrad) from 1.5 m above 

base of Niobrara Formation at USGS locality D10408 in the NE 1/4SW 1/4 

sec. 24, T. 33 N., R. 1 E., Cedar County, Nebr. USNM 299191. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 PLATE 15 

6 

;· 

12 14 

CENOMANIAN, TURONIAN, AND CONIACIAN MOLLUSKS 
Lower Upper Cretaceous Strata in 

Minnesota and Adjacent AreasTillle-Stratigraphic Correlations and 

Structural Attitudes 

By E. A. MEREWETHER 

STRATIGRAPHY AND PALEONTOLOGY OF MID-CRETACEOUS 

ROCKS IN MINNESOTA AND CONTIGUOUS AREAS 

G E 0 L 0 G I C A L S U R V E Y P R 0 F E S S I o· N A L P A P E R 1 2 5 3 - B 

A summary of the regional stratigraphy and structure of 

mid-Cretaceous formations in the Minnesota region and a 

comparison of these strata with mid-Cretaceous rocks in 

Wyoming 

CONTENTS 

Page 

Abstract -- ----- --- -- -- -- -- --- - --- -- -- - --- --- - - - - - --- ---- ---- --- ~- ------ - - --- -- -- -- ---- 27 

Introduction -------------------------------------------------------------------------- 27 

Previous work --- --- -- --- -- - ----- --- --- --- --- -- --- ----- ---- --- -- -- ---- -- --- -- --- -- --- -- 30 

Stratigraphy -------------------------------------------------------------------------- 31 

Rocks of Cenomanian Age --- -- ---- --- ---- ---- ----- -- ------ ----- ------ - --- -- --- --- - 32 

Rocks of Turonian Age ---- --- -- -- ---- --- -- -- ---- ---- --- --- - --- ----- -- ---- ---- --- - - 36 

Rocks of Coniacian and Santonian Ages - ---- --- --- ------- ---- ---- --------- --- -- -- -- - 40 

Summary of stratigraphy ---------------------------------------------------------- 41 

Structure -- -- ------ --- -- -- -- -- --- -- -- ---- --- --- -- -- -- ------ --- -- --- - --- -- ------ -- ---- - 42 

Marine regressions and transgressions in the Minnesota region compared with those in Wyoming 45 

References cited ---- -- -- ---- -- --- --- --- -- --- -- ---- -- ------ - --- -- -- -- --- ---- ----- ---- - - - 50 

ILLUSTRATIONS 

Page 

FIGURE 6. Map of the Minnesota region, showing locations of boreholes and outcrops used in 

this study, and cross section A-C ---------------------------------------- 28 

7. Correlation of the lower Upper Cretaceous formations at localities in northeastern Wyoming and the region of Minnesota---------------------------- 29 

8-11. Photographs showing: 

TABLE 

8. Irregular surface of Precambrian rocks in Dakota Granite Company's 

quarry ESE. of Milbank, S. Dak. -------------------------------- 32 

9. Uppermost Dakota Formation and overlying basal Graneros Shale on 

the big Sioux River near Westfield, Iowa ------------------------- 32 

10. Upper Cretaceous strata in the Ochs Brick and Tile Company's claypit 

about 3 km southwest of Springfield, Minn. ----------------------- 35 

11. Upper part of Greenhorn Formation at outcrop northeast of Browns 

Valley, Minn. - - - - - -- - - -- - - - -- - - -- - - - - -- - - - - -- - -- - -- - - - -- - -- -- - - 36 

12. Map showing approximate thickness of the Carlile Shale where overlain 

by the Niobrara Formation in the Minnesota region ----------------------- 38 

13. Photograph showing outcrop of Codell Sandstone Member of Carlile Shale, 

southeast of Mitchell, S.Dak.------------------------------------------- 39 

14. Photograph showing disconformable contact of Carlile Shale and overlying 

Niobrara Formation in northeastern Nebraska, west of Vermillion, S.Dak.-- 39 

15. Map showing approximate distribution of land and sea in North America 

during Coniacian time -------------------------------------------------- 42 

16. Map showing structures at the top of the Greenhorn Formation in the Minnesota region - - - - --- - - - -- -- - - - -- - - - - -- - -- -- - - - - -- - - -- - - - -- - -- - - -- - - - - -- - 43 

17. Cross section showing structure of Upper Cretaceous formations in northwestern 

Iowa, northeastern South Dakota, and Minnesota ------------------------- 44 

18. Map of the Minnesota region and States of the central Rocky Mountains, 

showing locations of part of the Powder River Basin and the Transcontinental 

arch----------------------------------------------------------------- 46 

19. Correlation of the lower Upper Cretaceous formations at localities in the Minnesota region and in Wyoming ------------------------------------------ 47 

20. Diagram of marine transgressions and regressions of mid-Cretaceous age, interpreted from strata in the Minnesota region and in Wyoming --------------- 48 

TABLES 

Page 

1. Boreholes in the Minnesota region-- --- -- -- ----- ----- ----- ---- -- -- --- ---- ---- 33 

2. Outcrops in the Minnesota region ------------------------------------------ 34 

STRATIGRAPHY AND PALEONTOLOGY OF 

MID-CRETACEOUS ROCKS IN MINNESOTA AND CONTIGUOUS AREAS 

LOWER UPPER CRETACEOUS STRATA IN MINNESOTA 

AND ADJACENT AREAS-TIME-STRATIGRAPHIC CORRELATIONS 

AND STRUCTURAL ATTITUDES 

By E. A. MEREWETHER 

ABSTRACT 

Sedimentary rocks of early Late Cretaceous age occur in the eastern 

parts of North Dakota, South Dakota, and Nebraska, and in Minnesota and western Iowa. They are generally included in, from oldest to 

youngest, the Dakota Formation, Graneros Shale, Greenhorn Formation, Carlile Shale, and Niobrara Formation. However, in eastern 

North Dakota, they are also assigned to, in ascending order, the Belle 

Fourche Shale, Greenhorn Formation, Carlile Shale, and Niobrara 

Formation. The Graneros Shale and laterally equivalent strata in the 

Belle Fourche Shale grade eastward into the Coleraine Formation of 

northeastern Minnesota and probably into the Windrow Formation of 

southeastern Minnesota. Cretaceous beds locally overlie rocks of 

Precambrian, Paleozoic, and Jurassic ages, and they are generally 

overlain by glacial drift and alluvium of Quaternary age. In Minnesota 

and adjoining areas, formations of mid-Cretaceous age commonly 

overlap the dissected surface of Precambrian rocks. The thickness of 

the lower Upper Cretaceous sequence ranges from about 223 m in 

eastern North Dakota and about 200m in northeastern Nebraska to a 

featheredge in Minnesota and Iowa. 

These lower Upper Cretaceous formations are composed mainly of 

shale, siltstone, sandstone, and limestone units of marine and nonmarine origin and were deposited near the eastern shore of a transgressing and regressing epicontinental sea in Cenomanian, Turonian, 

Coniacian, and Santonian time. During the late Cenomanian, the 

strandline was in Minnesota and was oriented generally northnortheast. Interpretations of the depositional environments of the 

strata and of fossils from outcrops and from clasts in glacial drift indicate that the Cretaceous seaway extended from this region 

northeastward across Canada to Greenland in the Turonian, Coniacian, and Santonian. 

The Cretaceous formations are deformed into broad, shallow synclines in eastern North and South Dakota and in northeastern 

Nebraska. A west-trending anticline, the Sioux uplift, separates the 

synclines in southeastern South Dakota. Sparse evidence of minor 

faulting in the formations exists in northeastern South Dakota, along 

the strike of a major southwest-trending zone of tectonism in the 

Precambrian basement rocks. The structural relief in the region, on the 

top of the Greenhorn Formation, is at least 250 m between eastern 

North Dakota and northeastern Minnesota, and at least 200m between 

northeastern Nebraska and northwestern Iowa. 

A com paris on of the Cretaceous stratigraphy of the Minnesota region 

and of areas in Wyoming indicates that some marine transgressions 

and regressions were synchronous in the two regions. The transgression 

during Greenhorn time, the regression during early Carlile time, and 

the transgression during late Carlile and Niobrara time seem to bemajor events caused by either continent-wide tectonism or eustasy. Other 

regressions and transgressions in Wyoming and northern Utah were 

probably caused by local structural deformation and by changes in the 

source and supply of sediments during deposition. 

INTRODUCTION 

Sedimentary rocks of early Late Cretaceous age are 

present in eastern parts of North Dakota, South Dakota, 

Nebraska, and in Minnesota and western Iowa (fig. 6). 

These rocks consist mainly of sandstone, siltstone, shale, 

and limestone, and were deposited in marine and nonmarine environments near the eastern shore of the 

Cretaceous epicontinental sea. 

The sequence of beds is as much as 223 m thick in 

eastern North Dakota (Bluemle, 1973, fig. 3) and about 

200 m thick in northeastern Nebraska, but it thins 

eastward to a featheredge in Minnesota and Iowa. The 

basal strata of the Cretaceous sequence transgressively 

overlap an erosion surface of great relief, which slopes 

down westward from high areas in Minnesota (Sloan, 

27 
28 

ggo 

,. 

. 

STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

. .. 

c:....• 

0 • ~ . 

~SOUTH 

D A ~0~ A 

0 

De Smei £. 

\. 

~ -;:. 

Sioux 

Falls 0 

N.E BRA s•K A 

ONTARIO 

Hib~ng 0 Virginia 

I' 

I 

~ 

/ 

Duluth/ 

c;.._,. 

r 

I 

I 

~ 

~S& ) W I S C 0 N S I N 

!/O'.s I 

o Litchfield ~ i 

Minneapo!is 0 ST <pAUL 

( 

"-~~'% ''\ 

0 Rochester ' '~ 

\ 

l o Worthington _) 

----------------------------~ 

Omaha c) ' 

xC 

0 Forest City 

IOWA 

0 Fort Dodge 

EXPLANATION 

SELECT BOREHOLE-Number indicates borehole described in 

Table 1 

SELECT OUTCROP-Letter indicates outcrop described in 

Table 2 

x:----x LOCATION OF CROSS SECTION 

A-C (FIG. 17) 

..... 

I 

\ 

' 

41°~~·~~---J----~----L_ ________ j_i_ _____ _l _________ _j __________ L_ ________ J_ ________ ~ 

100 200 KILOMETERS 

0 50 100 MILES 

FIGURE 6.-Map of the Minnesota region, showing locations of boreholes and outcrops used in this study, and cross 

section A-C. 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 29 

1964, p. 5). Beds of early Late Cretaceous age in much of 

the Minnesota region were truncated and dissected by 

glacial and fluvial activity during the Pleistocene and 

are overlain by Quaternary sediments. These Cretaceous 

strata are usually assigned to, in ascending order, the 

Dakota Formation, Graneros Shale, Greenhorn Formation, Carlile Shale, and Niobrara Formation (fig. 7). 

However, the Dakota in some areas may be entirely of 

Early Cretaceous age. 

This report is a compilation of the descriptions and interpretations of W. A. Cobban and the author, from field 

investigations and subsurface studies during 1977-79, 

and of the published and unpublished data of other 

workers. The purposes of this study are (1) to describe 

and interpret the lower Upper Cretaceous formations of 

the region, (2) to describe and interpret the structural attitudes of these strata, and (3) to compare the 

stratigraphy of the rocks in the Minnesota region, near 

the eastern shore of the Cretaceous sea, with the 

stratigraphy of rocks in Wyoming, near the western shore 

of the sea. Molluscan fossils from outcrops and boreholes 

in the Minnesota region were compared to the sequence 

of Western Interior index fossils (fig. 7) to determine the 

relative age of beds in the lower Upper Cretaceous fort:il 

"' < Een 

1:: 

as 

·a 

0 

c 

as 

en 

1:: 

·~ 

"§ 

u 

1:: 

<II 

·a 

e 

:::> 

E1:: 

<II ·a 

<II 

E 

0 

al 

u 

K-Ar A!(es (m.y.) Informal 

substage Western Interior fossil-zones' (Lanphere and 

Jones, 1978) 

26 Clioscaphites saxitonianus 

Lower 25 Scaphites depressus 

Upper 24 Scaphite.• ventricosus 

Middle 23 Inoceramus de{ormis 88.9 

22 Inoceramus erectu.' 

Lower 21 Inoceramus wa/tersdor{en.•is ?- 20 Prionocyclus quadratu.• 

19 Scaphites nigricollensis 

Upper 18 Scaphites whit{ieldi 

1,7 Scaphites warreni 

16 Prionocyclus macom bi 

1!j Prionocyclus hyatti 

14 Subprionocyc/us percarinatus Middle 13 Collignoniceras woollgari regulare 

12 Collignoniceras woollgari woollgari 

Lower 11 Mammites nodosoides 

10 Watinoceras coloradoen.'e 91.1 

9 Sciponoceras gracile 

Upper 8 Dunveganocera.• albertense 

7 Dunveganoceras pondi 93.5 

6 Plesiacanthocera.• wyomingense 

5 Acanthoceras amphibolum 94.4 

Middle 4 Acanthoceras alvaradoense 

3 Acanthoceras muldoonense 

2 Acanthoceras granerosense 

1 Calycoceras gilberti f--?-

Lower No molluscan fossil record 

96 

'Numbers representing some zones are shown in figure 17 and noted in text. 

2Age of basal contact of Niobrara Formation from Evetts (1976, p. 121 ). 

mations. Many of the mollusks listed in figure 7 represent several genera with the same age span, and the 

listed species do not occur in every collection used in this 

investigation. The thicknesses of stratigraphic units, 

reported herein, have not been affected by postCretaceous erosion unless otherwise noted. 

Several people have generously supplied unpublished 

data and interpretations which have been incorporated 

in the following pages. Doctor B. R. North and Professor 

W. G. E. Caldwell, University of Saskatchewan at 

Saskatoon, identified and interpreted specimens of 

Foraminifera in 20 samples from outcrops and cores. 

Palynomorphs in a sample of shale were described by R. 

H. Tschudy, of the U.S. Geological Survey. Fossils, 

borehole logs, and maps were provided by Professor G. 

W. Shurr, U.S. Geological Survey and St. Cloud State 

University, St. Cloud, Minn. Some of the molluscan index fossils, which were essential in correlating the 

Cretaceous strata, were collected by W. A. Cobban and 

R. E. Burkholder, U.S. Geological Survey; Cobban also 

identified all of the molluscan fossils in collections from 

the region. Cores of Cretaceous beds in eastern North 

Dakota were made available by S. B. Anderson, North 

Dakota Geological Survey, Grand Forks. Cores of strata 

Osa!(e area, Area of Sioux Area of the Southern northeastern City, Iowa, and Pembina River, Manitoba Wyomin!(~ Vermilli,m, S. Oak. N.Dak. 

Niobrara Fm. 

(lower part) Nwbrara Niobrara Niobrara 

~~ Formation Formation Formation 

......... ,... ........ ,.. .... ,..,..,.. ~ ., _____ 

• 

Sage 

Breaks 

Member 

"' Morden as Turner ..c: 

en Shale Sandy Carlile "' Member 

~ 

~~ 

Shale 

u 

Pool 

Member ? 

Creek 

Greenhorn 

Shale 

Carlile 

Gree~horn 

? 

~ Fa vel 

Formation Formation Formation 

Greenhorn ? 

Formation Graneros 

Shale t:: 

<II 

0. 

"' Belle 0. 

0. Belle 

Fourche 2 Fourche 

Belle Dakota Shale E Member .... Fourche Formation "' Shale ~ ..r:: 

..( 

? ?-

FIGURE 7.-Correlation of the lower Upper Cretaceous formatiOns at localities in northeastern Wyoming and the region of Minnesota. Hiatus 

in sequence patterned. Age of contacts with queries is estimated. 
30 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

in northwestern Iowa were provided by G. A. Ludvigson 

and B. J. Bunker of the Iowa Geological Survey, Iowa 

City. G. E. Prichard, U.S. Geological Survey, generously 

supplied stratigraphic data from boreholes in 

northeastern Nebraska. The munificent assistance of 

these people is gratefully acknowledged. 

PREVIOUS WORK 

During the past 175 years, many distinguished scientists have investigated the sedimentary rocks of 

Cretaceous age in Minnesota and Iowa, and in the 

eastern parts of Nebraska, South Dakota, and North 

Dakota (fig. 6). Some of their contributions to the 

stratigraphy of the region are summarized in the following paragraphs. 

Cretaceous strata typical of the region were observed 

by Meriwether Lewis and William Clark (Thwaites, 

1904, v. 7) along the Missouri River between Omaha, 

Nebr., and Yankton, S. Dak. (fig. 6), during their expedition of 1804-06. In 1810, Thomas Nuttall (Nuttall, 

1821) examined some of the outcrops and collected fossils in the same area. Specimens were also collected near 

the Missouri River by S. H. Long's party in 1819. With 

the aid of molluscan fossils from these expeditions and 

Lardner Vanuxem's recognition (Morton, 1828) of 

Cretaceous beds in New Jersey, Morton (1834) assigned 

the outcropping rocks along the upper Missouri River to 

the Cretaceous. 

Prince Maximillian von Wied Neuwied journeyed 

through the region in 1832, collected important 

Cretaceous fossils, and published his observations in 

1839-41. In 1839, J. N. Nicollet traveled up the Missouri 

River to Fort Pierre, S. Dak., examined outcrops that 

had been visited by Lewis and Clark, and then 

proceeded northeast to the Minnesota River. Nicollet 

(1841) identified Cretaceous limestone, marl, and clay 

along the Missouri River and obtained molluscan fossils, 

which were studied by Morton (1842). In 1849, John 

Evans examined the Cretaceous rocks near Sioux City, 

Iowa (fig. 6), and collected fossils, which were later 

described by D. D. Owen (Owen, 1852). 

F. V. Hayden and F. B. Meek first visited the upper 

Missouri River region in 1853 to gather fossils for James 

Hall. Data from their survey, which were presented by 

Hall and Meek (1856), included a composite section of 

the Cretaceous strata along the Missouri River between 

Fort Pierre, S.Dak., and Omaha, Nebr. Fossil leaves collected by Hayden from the basal sandstone of the sequence were assigned to the Miocene by Heer (1859) and 1 

reassigned to the Cretaceous by Newberry (1860). Meek : 

and Hayden (1862) named the lithologic units in their 

section, from oldest to youngest, as follows: "Dakota 

group" (mainly sandstone, 122 m thick), "Fort Benton 

group" (mainly clay, 244 m thick), "Niobrara division" 

(marl and limeston~, 61 m thick), "Fort Pierre group" 

(clay, 213m thick), ~nd "Fox Hills beds" (sandstone and 

clay, 152 m thick):· Marcou and Capellini studied the 

"Dakota group" near Sioux City, Iowa, in 1863 and concluded that the sandstone unit was of Cretaceous age 

and of freshwater origin (Marcou, 1864). Meek disagreed 

with Marcou and subsequently stated (Meek, 1865) that 

those rocks had been deposited in the brackish and normally saline waters of a bay or an estuary. The 

Cretaceous age of the Dakota along the Missouri River 

was later confirmed by Capellini and Heer (1866) and by 

Lesquereux ( 1868) from collections of fossil leaves. 

In 1870, White summarized the geology of Iowa and 

proposed that the Cretaceous strata be named, from 

oldest to youngest, "Nishnabotna sandstone, Woodbury 

sandstones and shales, and Inoceramus beds." White's 

Woodbury included the Dakota and Fort Benton of 

Meek and Hayden (1862); however, his nomenclature 

has since been abandoned. Rocks of Cretaceous age in 

Minnesota were first reported by Kloos (1872), who obtained molluscan fossils from clay and shale in a well 

near Richmond (fig. 6). Meek identified the fossils and 

concluded that the clay and shale were within the 

"Benton group." By 1878, Winchell had determined that 

Cretaceous beds underlie the glacial drift in most of 

western Minnesota. 

The Fort Benton, Niobrara, and Fort Pierre strata of 

Meek and Hayden (1862) were later included in the 

"Colorado group" by Hayden (1876) and by King (1876). 

These rocks are underlain by their "Dakota group" and 

overlain by their "Fox Hills group." However, in 1893, 

Calvin published a section of the outcropping 

Cretaceous strata near Sioux City, Iowa, which he assigned to the "Dakota group" (32m thick), "Fort Benton 

group" (12 m), and "Niobrara group" (9 m). Calvin 

(1893, p. 11) believed that the lower part of the Dakota 

had accumulated in brackish water and that the Fort 

Benton was deposited in "a clear open sea." 

The Cretaceous rocks of eastern South Dakota were 

described and interpreted in 1894 by Todd, whose 

stratigraphic nomenclature was essentially that of Meek 

and Hayden (1862). Todd applied the names Dakota 

Formation, Colorado Formation (including the Fort 

Benton, Niobrara, and Fort Pierre "sub-formations"), 

and Fox Hills Group. In a description of the geology near 

Sioux City, Iowa, Bain (1896) summarized the early 

reports and divided the Cretaceous sequence into the 

"Dakota formation" and the "Colorado formation." His 

Colorado consisted of the Fort Benton or Benton and the 

Niobrara. Later, after mapping outcrops near Mitchell, 

S. Dak. (fig. 6), Todd (1903) discovered that a sandstone 

that had been assigned to the Dakota Formation was 

younger than the Dakota and belonged in the upper part 

of the Benton Formation (the name Fort Benton was 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 31 

abandoned). As a consequence, Todd (1904) revised the 

Cretaceous stratigraphy and the stratigraphic terminology of the region. His nome':nclature for the Elk 

Point quadrangle of South Dakota,' Nebraska, and Iowa 

(Todd, 1908) includes, from oldest to youngest: Dakota 

Sandstone (107-122 m thick), Graneros Shale (2G-32 m), 

Greenhorn Limestone (about 9 m), Carlile Shale (61-66 

m), and Niobrara Formation (more than 61 m). The 

Graneros, Greenhorn, and Carlile are formations of the 

Benton Group. These names were also applied in 

Darton's (1909) description of the geology of South 

Dakota and have been used in many reports concerning 

the region since that time. Tester (1931) provided an excellent review of the geologic literature with a detailed 

description of the Dakota Sandstone near Sioux City, 

Iowa. More recently, the Dakota Formation of South 

Dakota was studied and described by Schoon (1965, 

1971). Agnew and Tychsen (1965) summarized the 

stratigraphic nomenclature and other pertinent information for mid-Cretaceous rocks in South Dakota. 

In south-central Minnesota, Cretaceous rocks of 

marine and continental origin were formerly named the 

Big Cottonwood Formation by Sardeson (1908). The 

scattered bodies of Cretaceous strata in southeastern 

Minnesota were named the Ostrander Member of the 

Dakota Formation by Stauffer and Thiel (1941, p. 103) 

and were later included in the Windrow Formation of 

Thwaites and Twenhofel (1921) by Andrews (1958). The 

Windrow of Andrews ( 1958) consists of the Iron Hill 

Member, an iron-rich regolith on rocks of pre-Cretaceous 

age, and the overlying East Bluff Member, which is composed of conglomerate, sandstone, and shale of nonmarine origin. Austin (1963, p. 3) and Sloan (1964, p. 

17-19) accepted most of Andrew's terminology but used 

the name Ostrander Member instead of East Bluff 

Member. The Cretaceous beds in south-central Minnesota were assigned by Parham (1970) to three informal 

stratigraphic units which, from oldest to youngest, consist of (1) kaolinitic residuum of Cretaceous age, (2) 

kaolinitic sandstone and clay of Late Cretaceous age; 

and (3) kaolinitic clay and overlying illitic and montmorillonitic strata of Late Cretaceous age. Parham 

(1970, p. 7) also reported that the contacts of his units 

are unconformities. In southwestern Minnesota, Austin 

(1972, fig. 5) recognized, in ascending order, residuum of 

Early and Late Cretaceous age, and the Dakota Formation, Graneros Shale, Greenhorn equivalent, Carlile 

Shale, Niobrara equivalent, and possibly the Pierre 

Shale of Late Cretaceous age. He also summarized the 

relative ages of the Cretaceous stratigraphic units in 

Minnesota. 

In northeastern Minnesota, conglomerate, sandstone, 

and shale of Cretaceous age locally mantle the irregular 

surface of Precambrian igneous and metamorphic rocks. 

White (1893) assigned these strata to the "Colorado 

series" and listed a few fossils from the beds. The sequence was formerly well exposed in open-pit mines 

between the towns of Coleraine and Virginia and was 

named the Coleraine Formation by Stauffer and Thiel 

(1941, p. 99). Bergquist (1944, p. 8) reported that the 

Coleraine was locally more than 30 m thick and that the 

formation was of marine origin at the western outcrops 

and largely of continental origin at the eastern outcrops. 

He also suggested that the formation was the same age 

as beds in the lower part of the Benton. 

In eastern North Dakota, the Cretaceous strata are 

commonly assigned to, from oldest to youngest: the 

Dakota Group, Colorado Group, and Montana Group 

(Hansen and Kume, 1970, p. 14-17; Arndt, 1975, fig. 2). 

In much of that area, the Colorado Group includes, in 

ascending order, the Belle Fourche Shale, Greenhorn 

Formation, Carlile Shale, and Niobrara Formation. 

STRATIGRAPHY 

The Upper Cretaceous rocks in the Minnesota region 

consist of sandstone, siltstone, shale, limestone, and 

minor conglomerate, lignite, and bentonite, and are as 

much as 329 m thick in northeastern North Dakota 

(Bluemle, 1973, fig. 3). These strata, which were 

deposited in marine and continental environments near 

the eastern shore of the shallow epicontinental sea, are 

generally assigned to, in ascending order, the Dakota 

Formation, Graneros 'Shale, Greenhorn Formation, 

Carlile Shale, Niobrara Formation, and Pierre Shale 

(fig. 7). However, in eastern North Dakota the rocks are 

included in the Colorado Group and the overlying Montana Group (Hansen and Kume, 1970, p. 14-17); and the 

Colorado Group is composed of, from oldest to youngest, 

the Belle Fourche Shale, Greenhorn Formation, Carlile 

Shale, and Niobrara Formation. Laterally equivalent 

strata in southern, Manitoba are assigned to, in 

ascending order, the Belle Fourche Member of the 

Ashville Formation, Favel Formation, Morden Shale, 

Niobrara Formation, and Pierre Shale (McNeil and 

Caldwell, 1981). The Pierre Shale, which was described 

by Gill and Cobban (1965), and other formations of the 

Montana Group are not treated herein. In Minnesota, 

Cretaceous units are named Windrow Formation 

(Andrews, 1958) in the southeastern part of the State, 

and Coleraine Formation (Stauffer and Thiel, 1941, p. 

99) in the northeastern part of the State. 

In most of the Minnesota region, the Cretaceous sequence is unconformably overlain by glacial deposits of 

Pleistocene age and by alluvium of Holocene age. Thesequence unconformably overlies rocks as young as Jurassic, in eastern North Dakota (Hansen and Kume, 1970, 

fig. 4), and as old as early Precambrian in western Minnesota (Sloan, 1964, fig. 2). The Cretaceous strata ac-
32 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

FIGURE 8.- Irregular surface of Precambrian rocks (local relief about 4 

m) in Dakota Granite Company's quarry about 9.1 km ESE. of 

Milbank, S. Dak. (SW Y4 sec . 18, T. 120 ., R. 47 W., Grant 

County). Dashed line, contact of Precambrian (p£) and midCretaceous ( K) rocks. 

cumulated by onlap on an irregular erosional surface 

(fig. 8), which sloped generally down to the west and had 

as much as 430 m of regional relief (Sloan, 1964, p. 5). 

The strata are locally nearly horizontal; consequently, 

the basal beds in the sequence vary greatly in age, being 

oldest in the channels and other low areas of the erosion 

surface in the western part of the region. 

ROCKS OF CENOMANIAN AGE 

In much of the Minnesota region (fig. 6), strata of 

Cenomanian age are the upper part of the Dakota Formation and the overlying Graneros Shale (fig. 7). 

However, in eastern North Dakota, Cenomanian beds 

are assigned to the Belle Fourche Shale, which is underlain by the Newcastle Sandstone (Hansen and Kume, 

1970, p. 14) or the Mowry Shale (Bluemle, 1973, p. 11). 

At outcrops in western South Dakota, the Newcastle and 

Mowry are of Early Cretaceous (pre-Cenomanian) age. 

Near the Missouri and Big Sioux Rivers, the Dakota Formation is as much as 140 m thick and is composed 

mainly of sandstone interbedded with siltstone, shale, 

and minor lignite (Darton, 1909, p. 46; Simpson, 1960, p. 

16; Schoon, 1971, fig. 1). At outcrops, the sandstone is 

commonly light brownish gray, very fine grained to 

medium grained, and cross stratified; it contains carbonaceous material, root casts, fossil leaves, and nonmarine pelecypods (fig. 9). Some of the shale in the 

Dakota at Sioux City, Iowa, is silty and contains burrows. Tester (1931, p. 280- 281) concluded that the formation in the type area, around Dakota City, Nebr., had 

been deposited in nonmarine and marine environments 

near the shoreline of a shallow sea. 

Similar rocks were encountered in borehole 1 (table 1) 

near Hawarden, Iowa (fig. 6), where the Dakota is about 

127 m thick and unconformably overlies strata of Devonian age (Ludvigson and Bunker, 1978). The thickness of 

the Dakota in eastern South Dakota commonly ranges 

from 15 to 140m (Schoon, 1971, fig. 1). In northeastern 

South Dakota and in the adjacent part of Minnesota, the 

formation is locally missing because of relief on the surface of the underlying Precambrian rocks. However, in 

borehole 3 (table 1) near Sisseton, S. Dak. (fig. 6), the 

Dakota Formation is about 44 m thick (Merewether and 

Gray, 1978, p. 9). 

Baker (1967, p. 17) reported that the Dakota in 

southeastern North Dakota thickens generally westward 

from a featheredge to more than 73 m. Cores of Cretaceous strata in eastern North Dakota include a basal 

unit of interstratified sandstone, siltstone, and shale, 

which Moore (1979, p. 122, 156) referred to as "basal 

Cretaceous clastics." Marine rocks within this sequence, 

at boreholes 10 and 11 (fig. 6; table 1), contain 

Foraminifera of Albian or Cenomanian Age (B. R. North 

and W. G. E. Caldwell, written commun., 1979). The 

unit of "basal Cretaceous clastics," which would 

traditionally be assigned to the Dakota, is probably of 

Early Cretaceous age and is as much as 87 m thick in 

boreholes in northeastern North Dakota (Moore, 1979, p. 

229). 

In central Minnesota, at the confluence of the Two 

River and the Mississippi River, outcrops of interbedded 

clay, shale, sandstone, and lignite were reported by 

Upham (1888, p. 601-603) and Allison (1932, p. 131), and 

assigned to the Dakota Formation by Stauffer and Thiel 

(1941, p. 175). Fossil pelecypods of fresh-water origin collected at this locality by Upham (1888, p. 602), were also 

found in the Dakota Formation near Dakota City in 

northeastern Nebraska and near Fairbury in southeastern Nebraska. 

FIGURE 9.- Uppermost Dakota Formation and overlying basal 

Graneros Shale on the Big Sioux River near Westfield, Iowa 

(Bain, 1895). 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 33 

TABLE !.-Boreholes in the Minnesota region (fig. 6) 

Location 

Borehole Driller Name State Township Range Section (North) (West) 

1 Iowa Geological Survey- Test D-7 ---- -- Iowa - ---- -- - - 5 95 47 

U.S. Geological 

Survey. 

2 U.S. Geological Survey Couteau No.2- Minnesota ---- 33 110 44 

3 Wismers Well Ruben Slather- South Dakota - 18 127 50 

Drilling Co. 

4 Unknown (Maclay and Unknown ----- Minnesota ---- 22 130 47 

others, 1968). 

5 - - -do ----------------------- Elbow Lake Test- - -do -------- 8 129 42 

hole. 

6 Unknown (Winter and Perham well -- - - -do --- - - --- 14 136 39 

others, 1969). 

7 Unknown (Lindholm and Sebeka well - -- - - -do - - - -- - - - 34 137 35 

others, 1972). 

8 Unknown (Bolin, 1956; Unknown -- -- - - - -do -- - -- - -- 23 50 27 

9 

Sloan, 1964, fi§. 5). 

U.S. Geological urvey Unknown -- --- - - -do -- --- -- - 27 54 25 

(Oakes, 1970). 

10 U.S. Dept. of Energy RRVD 7 ------ North Dakota - 23 137 53 

11 - - -do -- --- ---- --- -- ------ -- - RRVD 1 -- -- -- - - -do -- -- --- - 11 130 56 

12 - - -do ---- ------ -- ---- - --- -- - RRVD 2 -- -- -- - - -do -- -- -- - - 19 130 51 

13 Amaxlnc. - - - -- - - - - -- -- -- - -- - Core 9 -- - -- - - - Minnesota -- - - 4 122 30 

In southern Minnesota, a weathering residuum of 

Early and Late Cretaceous age (Austin, 1970) overlies 

Precambrian and Paleozoic rocks and is unconformably 

overlain by nonmarine and marine strata (Sloan, 1964; 

Parham, 1970), which Austin (1972, fig. 5) interpreted as 

mid-Cenomanian and correlated with the Dakota Formation. However, beds near Springfield, in southcentral Minnesota, contain fossils probably of late 

Cenomanian age; consequently, the rocks are described 

in the following paragraphs. 

The Graneros Shale is conformable and gradational 

with the underlying Dakota Formation. In the vicinity of 

Yankton, S. Dak. (fig. 6), the Graneros is as much as 50 

m thick and consists mainly of dark-gray shale (Condra, 

1908, p. 11; Simpson, 1960, p. 18). Locally, the Graneros 

is sandy at the base and calcareous at the top (Todd, 

1908, p. 2). Outcrops near Ponca, Nebr., are composed of 

flaser-like beds of calcareous siltstone and lesser 

amounts of shale, which contain small burrows parallel 

to the bedding. At Sioux City, Iowa, some outcrops of the 

basal Graneros (table 2, outcrop K) display interference 

ripples, scour marks, and small burrows, including 

Arenicolites. Except for some of the lowermost beds, the 

Graneros was deposited in offshore-marine environments. Molluscan fossils of marine origin, which have 

been collected from the lower part of the formation in the 

vicinity of Sioux City, include Dunveganoceras pondi 

Haas and Inoceramus prefragilis stephensoni Kauffman 

and Powell of late Cenomanian age (fig. 7, zone 7). At 

outcrops along the Big Sioux River and in borehole 1 

(table 1) near Hawarden, Iowa (Ludvigson and Bunker, 

1978; this report, fig. 6), the upper part of the Graneros 

contains Inoceramus ginterensis Pergament of late 

Cenomanian age, from the zone of Dunveganoceras 

albertense (Warren) (fig. 7, zone 8). 

Sparse outcrops of shale near the town of Mitchell, in 

southeastern South Dakota (fig. 6), contain palynomorphs of Albian or Cenomanian Age (R. H. Tschudy, 

written commun., 1979) and ammonites of indeterminate age. These rocks could be glacial erratics and are 

probably part of the Graneros Shale. Where penetrated 

by boreholes in the vicinity of DeSmet, S.Dak. (fig. 6), 

the formation is as much as 69 m thick (Bolin and 

Petsch, 1954, p. 84). At borehole 2 near Tyler, Minn., the 

Graneros is about 25 m thick and consists of fossiliferous, 

non calcareous shale and minor sandstone (C. R. Collier 

and H. R. Bergquist, written commun., 1969). In 

northeastern South Dakota in the vicinity of Aberdeen, 

the formation is as much as 88 m thick (Koch and Bradford, 1976, table 4). Near Sisseton, S.Dak., in borehole 3 

(fig. 6), the formation is about 58 m thick (Merewether 

and Gray, 1978, p. 9). The Graneros Shale of eastern 

South Dakota becomes the upper part of the Belle 

Fourche Shale in eastern North Dakota (Hansen and 

Kume, 1970, fig. 4). Boreholes 11 and 12 (table 1), in 

southeastern North Dakota, penetrated 67-80 m of shale 

and siltstone which Moore (1979, p. 122, 129) included in 

the Belle Fourche. Bluemle (1973, fig. 3) reported as 

much as 76 m of Belle Fourche in northeastern North 

Dakota. 

The Cenomanian beds assigned to the Dakota and 

Graneros near Sioux City, Iowa, are represented in 

southern Manitoba by marine noncalcareous shale, 

which was assigned to the Belle Fourche Member of the 

Ashville Formation by McNeil and Caldwell (1981; this 

report, fig. 7). Foraminifera in these rocks were cor-
34 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

TABLE 2.-0utcrops in the Minnesota region (fig. 6) 

Location 

Outcrop Unit Area State Township Section (North) Range 

A Graneros Shale Stone State Park Iowa - - - - - -- - - 26 90 48W. 

and Greenhorn near Sioux City. 

Formation. 

B Carlile Shale ----------- Dakota Granite Co. South Dakota 18 120 47W. 

c ~uarry near Milbank. 

Coleraine Formation ---- Hi -Annex mine, Minnesota ---- 16 56 23W. 

Mesabi Range. 

D Carlile Shale Pembina River --------------- North Dakota 34 163 57W. 

and Niobrara 

Formation. 

E Greenhorn Formation Browns Valley - - - - --- - --- ----- Minnesota - -- - 2 125 49W. 

and Carlile Shale. 

F Greenhorn Formation --- Quarry near Odessa --- -------- - - -do -------- 32 121 45W. 

G Windrow Formation ---- Och's claypit near - - -do -------- 26 109 35W. 

Springfield. 

H Carlile Shale ----------- Union County State South Dakota 29 94 50W. 

Park near Vermillion. 

Niobrara Formation----- Near confluence of James Nebraska----- 24 33 1E. 

River and Missouri River. 

J Carlile Shale ----------- Near Missouri River - - - do --- - -- - 3 31 5E. 

and Vermillion, S.Dak. 

K Graneros Shale --------- Sioux City ------------------- Iowa --------- 14 89 48W. 

related with a succession of Cenomanian ammonites, including Dunueganoceras albertense (Warren) (fig. 7), by 

Caldwell and others (1978, table 1). 

Marine and nonmarine fossils of late Cenomanian age, 

representing the zone of Dunueganoceras albertense 

(Warren) (fig. 7, zone 8), have been collected from the 

Coleraine Formation in iron mines of the Mesabi Range 

(table 2, outcrop C), in northeastern Minnesota (Berg.: 

quist, 1944; this report, fig. 6). The Coleraine in that 

area was reported to be more than 30 m thick. Most of 

the formation in the mines has been excavated, but it 

formerly consisted of a basal conglomerate overlain by 

sandstone and shale. These rocks contained fossilized 

mollusks, arthopods, fish teeth, reptile bones, and plant 

debris (Stauffer and Thiel, 1941, p. 106) and represented 

deposition in shallow-marine environments, in the 

western part of the Mesabi Range, and in nonmarine environments, in the eastern part of the range (Bergquist, 

1944, p. 8). In northwestern Iowa, marine fossils of the 

same age occur in the upper part of the Graneros Shale. 

Pierce ( 1961) reported that the Coleraine near the town 

of Virginia, Minn., contains palynomorphs of probable 1 

Cenomanian Age. Cretaceous shale and sandstone were' 

also encountered in boreholes located between the towns 

of Grand Rapids and Aitkin, southwest of the Mesabi 

Range (fig. 6). These beds are of nearshore, shallowmarine or brackish-water origin and contain Foraminifera that are probably of Cenomanian Age (Bolin, 1956, p. 

284-285). 

The Windrow Formation in southeastern Minnesota is 

at least 21 m thick (Austin, 1963, table 1) and consists of 

a basal ferruginous regolith (Iron Hill Member) and 

overlying poorly indurated clay, sandstone, and conglomerate (Ostrander Member) (Austin, 1963, p. 9; 

Sloan, 1964, p. 18). From paleontologic and stratigraphic 

data, Austin (1972, fig. 5) concluded that the Iron Hill 

Member is of Early Cretaceous and early Cenomanian 

age and that the Ostrander Member is of late Cenomanian age and, possibly, of Turonian, Coniacian, and Santonian Ages. These strata were deposited in nonmarine 

environments and are locally overlain by marine beds 

that contain shark teeth and Ophiomorpha (Austin, 

1972, p. 61). The Windrow grades westward into an unnamed sequence of nonmarine and marine beds. 

In south-central Minnesota, the Cretaceous sequence 

was divided by Parham (1970) into three stratigraphic 

units, which consist of, in ascending order: (1) kaolinitic 

residuum, (2) kaolinitic sandstone and kaolinitic clay, 

and (3) kaolinitic clay and overlying illitic and montmorillonitic beds. The contacts of these units are unconformities (Parham, 1970, p. 7). 

In the vicinity of New Ulm, Minn. (fig. 6), the Cretaceous sequence is at least 60 m thick and is composed 

of interstratified red, gr4y, and green shale and siltstone, 

gray and yellow sandstone, and thin beds of nodular 

limestone (Thiel, 1944, p. 121; Sloan, 1964, p. 20-21; 

Austin, 1970, p. 187). The sandstone is fine grained to 

coarse grained, locally pebbly and friable, and is either 

horizontally stratified, planar crossbedded, or trough 

crossbedded. Sloan (1964, p. 21) reported that the 

"direction of sediment transport * * * is almost due 

west." Most of these rocks were deposited in nonmarine 

environments, although a few outcrops display vertical 

burrows and are probably of marine origin. Lesquereux 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 35 

(1895) assigned some of these strata to the "Dakota 

group" and related them to the Cenomanian through 

studies of fossil leaves. Pierce (1961) sampled outcrops of 

Cretaceous rocks near New Ulm, Redwood Falls, and 

Richmond, Minn. (fig. 6), and reported that the 

palynomorphs in the sampled beds are of Cenomanian 

Age. He also concluded that during the early Late 

Cretaceous, south-central Minnesota had little topographic relief (probably less than 150m) and had a warm 

temperate climate similar to the climate of rain forests 

in the Pacific Northwest. Later investigations by Austin 

(1970, p. 193) of the rocks at New Ulm determined that 

the basal regolith probably "is no younger than early 

Cenomanian" and that differences in the clay 

mineralogy of the overlying beds are evidence of a 

climatic change during the Cenomanian- from humid 

tropical to temperate. Austin (1972, fig . 5) also proposed 

that these rocks and others in the Minnesota River Valley are of Early and Late Cretaceous age. Parham's 

(1970) residuum is of Early Cretaceous and early 

Cenomanian age, and the overlying units of strata are 

about middle Cenomanian (Austin, 1972, fig. 5). 

Sloan (1964, p. 21) reported that the Cretaceous sequence in the vicinity of Springfield, Minn. (fig. 6), is 

mainly light gray shale and is at least 61 m thick. In the 

Ochs Brick and Tile Company's new claypit near 

Springfield (table 2, outcrop G), the Cretaceous rocks 

consist of a unit of siltstone and interlaminated siltstone 

and shale about 7.6 m thick, and an overlying unit of 

shale, siltstone, and minor sandstone and lignite about 

6.9 m thick (Sloan, 1964, p. 22). The basal unit (fig. 10) 

contains sparse burrows and trochamminid Foraminifera (B. R. North and W. G. E. Caldwell, written commun., 1979). Ferruginous concretionary beds in the upper unit contain fossil wood with borings, burrows, fish 

bones, shark teeth, and molluscan fossils of nearshoremarine and brackish-water origin. The mollusks include 

Anatimy a plicata Bergquist, a marine bivalve also found 

in upper Cenomanian beds of the Coleraine Formation in 

the Mesabi Range. A single specimen of the late 

Cenomanian ammonite Dunueganoceras albertense 

(Warren) (fig. 7, zone 8), was obtained from red shale in 

an excavation in the town of Comfrey, Minn., about 17 

km southeast of Springfield. This red shale resembles 

beds in the sequence at New Ulm and was "probably 

derived from the Sioux Quartzite" in the area (Sloan, 

1964, p. 27). However, the fossil could have been transported by glacial activity and, therefore, may not reflect 

the age of the local strata. Nevertheless, some of the 

Cretaceous rocks near Springfield probably are of late 

Cenomanian age (fig. 7, zone 8); these would be shallowmarine and nonmarine facies of the Graneros Shale. A 

core from borehole 2 near Tyler, in southwestern Minnesota (fig. 6) , contains Foraminifera which were studied 

FIGURE 10- Upper Cretaceous strata in the Ochs Brick and Tile 

Company's claypit about 3 km southwest of Springfield, Minn. 

(table 2, outcrop G). This marine and nonmarine sequence is about 

8.6 m thick and includes a bed of lignite (arrow), about 30 em t hick, 

near the top. 

by Bergquist (written commun., 1969). He suggested 

that the noncalcareous shale and sandstone at depths of 

246- 264 m (807- 866 ft) are approximately equivalent to 

the Graneros Shale and are of Cenomanian Age. Schoon 

(1965) and Austin (1972) indicated that the mainly nonmarine Dakota Formation of eastern South Dakota and 

adjoining areas was deposited during a marine transgression, and, therefore, the formation was progressively 

younger from west to east. The Dakota and the overlying 

lower part of the Graneros Shale at Sioux City, Iowa, include beds of late Cenomanian age (fig. 7, zone 7) and 

could presumably include younger beds of late Cenomanian age northeast of Sioux City, near Springfield and 

New Ulm, Minn. The nonmarine and shallow-marine 

strata of Cenomanian Age, which overlie the residuum at 

Springfield and New Ulm, are lithologically similar to 

the Dakota and the lower part of the Graneros at Sioux 

City; but the fossils indicate that some of the strata near 

Springfield are of mid-Graneros age (late Cenomanian; 

fig. 7, zone 8). On the basis of these data and interpretations, the strata at Springfield and New Ulm and the 

Ostrander Member of the Windrow Formation in 

southeastern Minnesota are, at least partly, of late 

Cenomanian age as Austin (1972) proposed, and the 

marine beds, which overlie the Windrow, may be 

laterally equivalent to the Greenhorn Formation. 
36 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

ROCKS OF TURONIAN AGE 

Strata of Turonian Age crop out and have been 

penetrated by boreholes in the eastern parts of 

Nebraska, South Dakota, and North Dakota, and in the 

western parts of Minnesota and Iowa. In much of this 

region, these beds are assigned to the Greenhorn Formation and to the overlying Carlile Shale. At outcrops, the 

limestone in the Greenhorn forms ledges and the shale in 

the Carlile generally forms slopes. 

The Greenhorn Formation conformably overlies either 

the Graneros Shale or the Belle Fourche Shale. Along the 

Missouri and Big Sioux Rivers, the Greenhorn is about 9 

m thick and consists mainly of interbedded fossiliferous 

limestone and calcareous shale (Burchard, 1904, p. 151; 

Todd, 1908, p. 2; Simpson, 1960, p. 18-19), which were 

deposited largely in open-marine environments. The fossils are mostly fragments of the bivalve Mytiloides 

mytiloides (Mantell) of early and middle Turonian age, 

but they include the cephalopod Collignoniceras woollgari of middle Turonian age (fig. 7, probably zone 12), at 

the top of the formation. 

In borehole 1 near Hawarden, Iowa (fig. 6), the 

Greenhorn is 8 m thick and consists of interlaminated 

limestone and calcareous shale. The formation was also 

penetrated by borehole 2 near Tyler, Minn. (fig. 6), 

where the sequence is about 13 m thick and is composed 

largely of calcareous shale (C. R. Collier and H. R. Bergquist, written commun., 1969). In boreholes near De 

Smet, S.Dak., the Greenhorn is 7-10 m thick (Bolin and 

Petsch, 1954). 

In northeastern South Dakota and the adjacent part of 

Minnesota, the Greenhorn crops out and was also encountered in stone quarries and boreholes. In boreholes 

near Aberdeen, S. Dak., the formation is as much as 21 

m thick (Koch and Bradford, 1976, table 4). The formation is about 9-11 m thick where penetrated by water 

wells near Sisseton, S. Dak. (Merewether and Gray, 

1978, p. 9; this report, fig. 6). Shurr (1979) described the 

upper part of the Greenhorn at an outcrop (table 2, outcrop E) near the town of Browns Valley, Minn., where 

the formation consists mainly of thin beds of limestone 

and chalk and is about 3 m thick (fig. 11). Fossils in 

these beds include the pelecypod Mytiloides mytiloides 

(Mantell) (fig. 7, zones 11 and 12) and the ammonite 

Watinoceras coloradoense (Henderson) (fig. 7, zone 10) 

of early Turonian age. In quarries near Odessa, Minn. 

(fig. 6; table 2, outcrop F), the Greenhorn contains 

Mytiloides mytiloides (Mantell), oysters, and fish bones; 

and it overlies rocks of Precambrian age. Where 

penetrated by boreholes 11 and 12 (table 1) in 

southeastern North Dakota, the formation is 9-12 m 

thick and is composed of fossiliferous, silty shale (Moore, 

1979, p. 122, 129). 

Hansen and Kume (1970, fig. 4) reported that the 

Greenhorn in the vicinity of Grand Forks is as much as 

29 m thick and consists of interstratified madstone, 

calcareous shale, limestone, and bentonite. The 

Greenhorn is represented in Manitoba and Saskatchewan, Canada, by the Keld Member of the Favel 

Formation (fig. 7), which is composed mainly of 

calcareous shale and contains Mytiloides mytiloides 

(Mantell) (McNeil and Caldwell, 1981). 

Lindholm, Oakes, Ericson, and Helgesen (1972) noted 

FIGURE 11.-Upper part of Greenhorn Formation (about 3 m thick) at outcrop 8 km northeast of Browns Valley Minn. (table 2, outcrop E). 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS· 37 

that borehole 7 in central Minnesota (fig. 7; table 1) was 

producing water reportedly from a Cretaceous limestone, 

which may be part of the Greenhorn Formation. Samples of shale from borehole 13 (table 1) near Richmond, 

Minn., were supplied by G. W. Shurr and examined for 

Foraminifera by B. R. North and W. G. E. Caldwell. The 

sparse fauna in samples of calcareous and noncalcareous 

shale is characteristic of the Greenhorn and the lower 

part of the Carlile. If the upper part of the Windrow Formation in southeastern Minnesota consists of nonmarine 

strata of Graneros age (late Cenomanian), the overlying 

marine rocks (Austin, 1972, p. 61) may represent the 

Greenhorn. 

The Carlile Shale conformably overlies the Greenhorn 

Formation and is composed of noncalcareous shale and 

minor calcareous shale of offshore-marine origin, and 

minor sandstone of nearshore-marine origin. In the Minnesota region, the Carlile is generally 40-120 m thick 

(fig. 12); in much of the region it is unconformably 

overlain by the Niobrara Formation. At outcrops in the 

vicinity of Vermillion, S. Dak., the Carlile is 50-65 m 

thick and contains fossiliferous calcareous concretions 

and sparse sandstone in the upper part of the formation 

(Todd, 1908, p. 2; Condra, 1908, p. 12). The fossils include Subprionocyclus percarinatus (Hall and Meek) of 

middle Turonian age (fig. 7, zone 14). A core of the lower 

part of the Carlile from borehole 1 near Hawarden, Iowa 

(fig. 6), contains Collignoniceras woollgari regulare of 

middle Turonian age (fig. 7, zone 13). 

In water wells in eastern South Dakota and at outcrops along the James River near Mitchell (fig. 6), the 

upper part of the Carlile commonly includes a body of 

sandstone which has been assigned to the Codell Sandstone Member of the Carlile Shale (Barkley, 1952). The 

sandstone member is at the top of the Carlile or as much 

as 15 m below the top of the formation, and it is generally 

6-15 m thick (Todd, 1903, p. 2). Near Mitchell, the 

average thickness of the Codell is about 14m (Steece and 

Howells, 1965, p. 40). Darton (1909, p. 49) reported that 

the sandstone is brown, massive, coarse grained, and 

locally pebble bearing and cross bedded. Todd ( 1903, p. 

2) reported that the Codell near Mitchell contains shark 

teeth and, at a few outcrops, traces of fossil wood and 

leaves. At some outcrops between Mitchell and Olivet, 

S.Dak., the lower part of the member is composed ofinterstratified calcite-cemented and friable sandstone and 

lesser amounts of clay. The sandstone in the Codell is 

fine grained to coarse grained and locally contains pebbles, as much as 5 em in diameter, of shale, sandstone, 

limestone, chert, and phosphatic material. Sequences of 

sandstone beds commonly are coarser grained at the top 

than at the base. Units of sandstone are as much as 8 m 

thick and are irregularly bedded and cross stratified. 

(Some tabular sets are about 30 em thick; see fig. 13.) 

Outcrops southeast of Mitchell (SWV4 sec. 17, T. 102 N., 

R. 59 W.; fig. 6) display herringbone crossbeds and other 

planar crossbeds,, which indicate many paleocurrent 

directions, and overturned foreset laminae, which indicate strong sediment-laden currents. Between 

Mitchell and Olivet, the member contains bone fragments, fish teeth, bored wood, and Thalassinoides. The 

Codell Sandstone Member in southeastern South 

Dakota was deposited in shallow-marine environments 

near the eastern shore of a Turonian sea. At the outcrops near Mitchell (fig. 6), the Codell may have been 

deposited in a delta-front environment. The member 

and the underlying marine shale probably represent a 

marine regression in eastern South Dakota during middle Turonian time. Rice (1977) has shown that the 

Codell can be traced westward to a featheredge in 

central South Dakota and that it does not grade 

westward into the Turner Sandy Member of the Carlile 

Shale of western South Dakota. 

In boreholes near DeSmet, S.Dak., the Carlile Shale 

generally is 40-60 m thick (Bolin and Petsch, 1954). 

Cores and drill cuttings from the Carlile in borehole 2 

near Tyler, Minn. (fig. 6), consist mainly of fossiliferous, 

noncalcareous shale. In northeastern South Dakota, the 

formation is as much as 84 m thick near Aberdeen (Koch 

and Bradford, 1976, table 4) and about 70 m thick at 

borehole 3 (Merewether and Gray, 1978, p. 9-10). At outcrops in the area, the Carlile is composed of shale and 

minor siltstone and sandstone. At outcrop B (table 2) in 

the Dakota Granite Company's quarry, a lower part of 

the formation is about 5 m thick and consists of fossiliferous, calcareous shale. These beds, which rest on 

Precambrian rocks (fig. 8), are slightly sandy at the base 

of the sequence and enclose scattered, rounded pebbles 

of chert as much as 2 em long, rounded pieces of fossil 

wood, as much as 15 em long, abundant fossil fish bones, 

and molluscan fossils. The mollusks include Collignoniceras woollgari regulare of middle Turonian age 

(fig. 7, zone 13). A lower part of the Carlile and the underlying Greenhorn Formation crop out near Browns 

Valley, Minn. (table 2, outcrop E). The Carlile at this 

outcrop is about 36 m thick and is mainly noncalcareous 

shale, but it includes calcareous shale at the base of the 

sequence and a unit of sandstone and siltstone, about 6 

m thick, near the top of the sequence (Shurr, 1979, p. 8). · 

An ammonite collected from about 1.5 m below the 

sandstone unit has been tentatively identified as 

Subprionocyclus percarinatus (fig. 7, zone 14) of middle 

Turonian age. 

In southeastern North Dakota at borehole 11 (fig. 6; 

table 1), the Carlile Shale is at least 58 m thick (Moore, 

1979, p. 122). Hansen and Kume (1970, fig. 4) reported 

that the Carlile in the area of Grand Forks, N.Dak., is as 

much as 79 m thick. In northeastern North Dakota, the 

formation reportedly is about 73 m thick (Bluemle, 1973, 

fig. 3) but probably ranges from about 70 to 120 m in 

thickness (fig. 12). The upper part of the Carlile crops 

out along the Pembina River in northeastern North 

Dakota where it is conformably overlain by the Niobrara 

Formation (table 2, outcrop D). Arndt (1975, p. 5-6) 
38 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

Cloud 

92° 91° r-l 

ONTARIO I 

I 

'~ \ \.''"" ' 

/ 

I 

~ 

\.7,. ...... /1 

/ 

Duluth/ 

(j-,.,-

r 

I 

I 

~ 

l 

-ws,s. ) W I S C 0 N S I N 

o Litchfield !{reS~ { 

Minneapolis a ST ~AUL I 

'\._"~~ ''\ 

0 Rochester ' '~ 

\ 

i 

______ o_w~~-in-gt-on _________________ -l 

0 

xB 

o Forest City 

EXPLANATION 

SELECT BOREHOLE-Number indicates borehole described in 

Table 1 

SELECT OUTCROP-Letter indicates outcrop described in 

Table 2 

x:----x LOCATION OF CROSS SECTION 

A-C (FIG. 17) 

--40-- ISOPACHOUS LINE-Contour 

interval 20 m 

FAULT 

..... 

I 

(~ \, 

j_ ____ _L_ ____ j 

100 200 KILOMETERS 

50 100 MILES 

FIGURE 12.-Approximate thickness of the Carlile Shale where overlain by the Niobrara Formation in the Minnesota 

region. 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 39 

FIGURE 13.- 0utc rop of Codell Sandstone Member of Carlile Shale, 11 

km southeast of Mitchell, S.Dak. (SW 1/4 sec. 17, T . 102 N ., R. 59 

W., Hanson County) . Crossbedded sequence is about 1 m thick. 

stated that the upper part of the Carlile in this area consists of at least 30m of mostly noncalcareous black shale. 

Fossil mollusks collected from about 40 m below the top 

of the formation by Wosick (1977) include Scaphites that 

resemble species of probable latest Turonian or earliest 

Coniacian age (fig. 7, zones 20 or 21). 

The Carlile Shale of North Dakota is included in the 

upper part of the Favel Formation and the Morden Shale 

of Manitoba, Canada (fig. 7). Apparently, the Morden 

Shale of McNeil and Caldwell (1981) includes beds of 

Turonian Age that are represented by an unconformity 

at the top of the Carlile in eastern South Dakota and adjacent areas. 

Some of the Carlile Shale was penetrated by borehole 

2 (fig. 6) in southwestern Minnesota and by boreholes 

and wells in central Minnesota near the town of Richmond. In 1872, Kloos described the clay, shale, and 

minor lignite encountered in a water well south of Richmond. That sequence of beds, which is about 22m thick, 

contains marine fossils of middle Turonian age (fig. 7, 

zones 12, 13, or 14) and probably is a lower part of the 

Carlile. Samples of shale provided by G. W. Shurr, from 

borehole 13 (table 1) in the same area, contain Foraminifera that are typical of the lower part of the Carlile (B. 

R. North and W. G. E. Caldwell, written commun., 

1979). 

At outcrops along the Missouri River between Vermillion and Yankton, S. Dak., shale in the upper part of the 

Carlile is sharply overlain by calcareous strata of the 

Niobrara Formation (fig. 14). The Cod ell Sandstone 

Member of the Carlile is absent in much of that area. 

Georgesen (1931, p. 31) and Simpson (1960, p. 20) indicated that the Carlile-Niobrara contact at those outcrops is a disconformity with as much as 60 em of local 

relief. Furthermore, molluscan fosssils from the upper 

part of the Carlile (fig. 7, zone 14) and the basal 

Niobrara (fig. 7, zone 24) indicate a significant hiatus at 

the contact (Hattin, 1975, p. 200- 201). In contrast, the 

upper part of the Carlile and the basal Niobrara are 

gradational and seem to be conformable at outcrops 

along the Pembina River in northeastern North Dakota. 

FIGURE 14.-Disconformable contact of Carlil e Shale and overlying Niobrara Formation in 

northeastern Nebraska, about 19 km west of Vermillion, S .Dak. (NW14 sec. 12, T . 32 N., R. 2 

E., Cedar County). Hammer at contact is 28 em long. 
40 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

Moreover, fossils from the Carlile in that area probably 

represent zone 20 or 21 (fig. 7) and those from the basal 

Niobrara, zone 24 (fig. 7). The hiatus of the Yankton 

area is either absent or relatively small near the Pembina River. 

ROCKS OF CONIACIAN AND SANTONIAN AGES 

In the Minnesota region, strata of late Coniacian and 

Santonian age are within the Niobrara Formation. At 

outcrops along the Missouri River between Elk Point 

and Yankton, S. Dak. (fig. 6), the Niobrara consists 

mainly of argillaceous limestone and is as much as 62 m 

thick (Simpson, 1960, p. 21). A sharp contact divides the 

Niobrara from the underlying Carlile Shale (fig. 14). 

Near Yankton (table 2, outcrop 1), the basal Niobrara 

contains the inoceramid Volviceramus involutus (J. 

Sowerby) of late Coniacian age and the trace fossil 

Thalassinoides, which lies parallel to the bedding 

planes. The upper part of the formation in that area contains Platyceramus platinus (Logan) of Santonian Age. 

Where penetrated by boreholes near De Smet, S. 

Dak., the Niobrara is commonly 42-47 m thick (Bolin 

and Petsch, 1954). Koch and Bradford (1976, table 4) 

reported that the formation is as much as 52 m thick in 

the vicinity of Aberdeen, S. Dak. In borehole 3 (fig. 6) in 

northeastern South Dakota, the Niobrara is probably 

about 15 m thick (Merewether and Gray, 1978, p. 10). 

The formation crops out in eastern North Dakota, 

west of Grand Forks (fig. 6), where it consists largely of 

marlstone and shale and is as much as 35 m thick 

(Hansen and Kume, 1970, p. 15, fig. 4). In northeastern 

North Dakota, the Niobrara conformably overlies the 

Carlile Shale at outcrops along the Pembina River (table 

2, outcrop D). Arndt (1975, p. 6) reported that the 

Niobrara in that area is mainly calcareous shale and is at 

least 46 m thick. The Niobrara near the Pembina River 

includes a unit of noncalcareous shale, which contains 

Platyceramus platinus of Santonian age, and an underlying basal unit of calcareous shale, which contains 

Volviceramus involutus (J. Sowerby) of late Coniacian 

age. In southernmost Manitoba, Canada, the Niobrara is 

about 50 m thick and consists mostly of calcareous shale 

(McNeil and Caldwell, 1981). 

Outcrops of shale and clay along the Little Fork and 

Big Fork Rivers in northeastern Minnesota, were 

ascribed to the Cretaceous by Winchell (1893, p. 220). 

Microfossils from strata near the Little Fork were 

described by Woodward and Thomas (1895) and were 

tentatively assigned to Coniacian-Santonian time by 

Bolin (1956, p. 279). After studying illustrations of these 

microfossils, W. G. E. Caldwell and Ruth North (written 

commun., 1978) suggested that the species were typical 

of the microfauna in the Niobrara Formation. Thiel 

(1947, p. 151) has reported fossiliferous, bluish-gray clay, 

in a layer about 12 m thick, at a locality near the Little 

Fork River. However, Thiel (1947) and Bolin (1956) also 

indicated that the beds, where unfossiliferous, are not 

easily distinguished from Quaternary sediments. Consequently, the shale and clay in northeastern Minnesota 

may be of Quaternary age, and the Cretaceous fossils 

may have been transported southward from outcrops in 

Canada and redeposited in this area by Pleistocene 

glacial activity. 

Woodward and Thomas (1885) also reported Cretaceous Foraminifera in Pleistocene clay near Litchfield in 

central Minnesota. Their drawings of many species have 

been studied by W. G. E. Caldwell and Ruth North 

(written commun., 1978), who have tentatively proposed 

that the fauna was derived from the Niobrara Formation. 

Outcrops of sedimentary rocks near Marshall and 

Redwood Falls, in southwestern Minnesota (fig. 6), contain Foraminifera, which Bolin (1956, p. 284-285) indicated were typical of the Niobrara in Nebraska and 

South Dakota. He also suggested that the rocks may be 

reworked deposits of glacial origin. Bolin's sample 

locality northwest of Marshall is in the same area as outcrops of clay (Winchell, 1874, p. 189) and marine sandstone. Winchell (187 4, p. 189) stated that the clay is 

blue, but yellowish-blue where weathered, and "at least 

ten or fifteen feet" (3 or 5 m) thick. The sandstone is very 

fine grained, well sorted, and calcareous, and it includes 

some beds of ironstone. It also displays ripplecrossbedding, ripple marks, and abundant burrows; it 

weathers to slabs. Rodis (1963, fig. 5) located this outcrop and reported sandstone at altitudes of 320-354 min 

a northwest-trending area that extends from Marshall to 

Taunton. He also reported limestone at altitudes of 

378-384 m in a small area west of Marshall and 

northeast of Tyler. The limestone unit is generally about 

2 m thick, fine grained, thickly bedded, and poorly indurated, and it locally overlies thin, discontinuous beds 

of sandstone (Rodis, 1963, p. N12-15). If the strata in 

these areas are horizontal, as Rodis (1963, p. N13) suggested, then they can probably be correlated with the 

rocks in borehole 2 near Tyler (fig. 6) by the use of 

altitudes. In borehole 2, the top of the Greenhorn Formation is at an altitude of about 300m, the top of the truncated Carlile sequence is at an altitude of about 344m, 

and the Niobrara Formation apparently has not been 

preserved. The limestone described by Rodis (1963, p. 

N15) resembles the Niobrara in eastern South Dakota, 

although it is thinner, and correlates with strata a hove 

the Carlile in borehole 2. The unit of limestone in the 

Marshall-Tyler area is probably part of the Niobrara and 

is similar to the basal part of the formation in eastern 

South Dakota. However, the rocks near Taunton, which 

contain microfossils typical of the Niobrara (Bolin, 1956, 

p. 283), are at altitudes of about 340-350 m, which is 

significantly below the limestone unit. Furthermore, the 

lithology of the strata near the fossil locality seems more 

like that in the upper part of the Carlile, as Darton 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 41 

(1909, p. 52) suggested, than that of the Niobrara. These 

rocks could, however, be a sandy facies of the Niobrara 

that was deposited in nearshore-marine environments. 

SUMMARY OF STRATIGRAPHY 

In the vicinity of Sioux City, Iowa, the oldest formation treated in this report, the Dakota Formation, is 

composed dominantly of sandstone and was deposited in 

nonmarine and shallow-marine environments. Inasmuch 

as the formation in that area is conformably overlain by 

fossiliferous beds of late Cenomanian age (fig. 7, zone 7), 

it can be inferred that at least the upper part of the 

Dakota is of Cenomanian Age. The sandstone in this 

part of the formation in northwestern Iowa grades 

northward into shale of offshore-marine origin in eastern 

North Dakota. This laterally equivalent shale is in the 

lower part of the Belle Fourche Shale. The thickness of 

the Dakota ranges from about 140 m near Sioux City, 

where the formation is probably of Early and Late 

Cretaceous age, to about 124 m near Grand Forks, N. 

Dak. (Hansen and Kume, 1970, fig. 4), where the formation is of Early Cretaceous age. Sloan (1964, p. 5, fig. 11) 

interpreted the local thinning and the local absence of 

the Dakota in eastern South Dakota, southwestern Minnesota, and northwestern Iowa, where the Dakota and 

younger formations rest on Precambrian rocks, as 

evidence of an embayed coast of moderate relief. 

The Graneros Shale of northwestern~ Iowa, northeastern Nebraska, and eastern South Dakota and the 

upper part of the Belle Fourche Shale of eastern North 

Dakota are composed largely of shale, which was 

deposited in offshore-marine environments during late 

Cenomanian time (fig. 7, zones 7-9). However, the basal 

part of the Graneros is locally of nearshore-marine origin 

where it overlies Precambrian rocks in eastern South 

Dakota and adjacent areas. The Graneros is as much as 

50 m thick near Yankton, S. Dak., and the Belle 

Fourche, which includes some older beds, is about 76 m 

thick in northeastern North Dakota (Bluemle, 1973, fig. 

3). Some of these strata are represented in northeastern 

Minnesota by the shale, sandstone, and conglomerate of 

nearshore-marine and nonmarine origin in the Coleraine 

Formation. Marine fossils in the Coleraine are of late 

Cenomanian age (fig. 7, zone 8). Part of the Graneros is 

probably represented in south-central Minnesota by 

some of the shale, sandstone, and lignite of shallowmarine and nonmarine origin near Springfield, and in 

southeastern Minnesota by some of the Windrow Formation. The fossil fauna and flora in these rocks are of 

Cenomanian Age and resemble the fossils in the 

Coleraine Formation. 

The Greenhorn Formation in eastern North Dakota, 

eastern South Dakota, and adjacent areas consists 

mainly of calcareous shale and limestone (fig. 11) of 

offshore-marine and open-marine origin. However, the 

formation is of nearshore-marine origin where it onlaps 

Precambrian rocks in westernmost Minnesota (table 2, 

outcrop F). Molluscan fossils of early and middle Turonian age (fig. 7, zones 10-12) are common in these beds. 

A fossiliferous, noncalcareous shale in borehole 13 (table 

1) near Richmond, in central Minnesota, is probably a 

lateral equivalent of the Greenhorn. The thickness of the 

formation ranges from about 7 m near DeSmet, S.Dak. 

(Bolin and Petsch, 1954), to about 29 m near Grand 

Forks, N. Dak. (Hansen and Kume, 1970, fig. 4). 

In northwestern Iowa, northeastern Nebraska, and 

eastern South Dakota, the Carlile Shale is comprised 

largely of calcareous and noncalcareous shale; it also 

commonly includes the Codell Sandstone Member at the 

top of the formation. These strata were deposited during 

the middle Turonian (fig. 7, zones 12-14) in offshoremarine and nearshore-marine environments. In eastern 

North Dakota, the Carlile consists of shale of offshoremarine origin, without the Codell Sandstone Member, 

and includes strata as young as latest Turonian or 

earliest Coniacian (fig. 7, zone 20 or 21). The formation 

ranges in thickness from about 40 m in southeastern 

South Dakota to about 120 m in northeastern North 

Dakota. Shale of middle Turonian age, probably in the 

lower part of the Carlile, was also encountered in wells 

and boreholes near Richmond, Minn. The Codell Sandstone Member of eastern South Dakota, which thins to a 

featheredge in central South Dakota, probably was 

deposited in shallow-marine, delta-front, and nearshore 

bar environments. Regional differences in the age of the 

upper part of the Carlile (Hattin, 1975, text fig. 5) and in 

the thickness of the formation are evidence of an erosion 

surface at the top of the Carlile in eastern South Dakota 

and adjacent areas. The amount of truncation varies 

locally but seems to decrease generally toward the west. 

The Niobrara Formation ranges in thickness from 

about 62 m near Yankton, S. Dak., to about 15 m in 

borehole 3 in northeastern South Dakota, and to about 

50 m in southernmost Manitoba, Canada. Sparse collections of molluscan fossils indicate that the formation is 

at least of late Coniacian and early Santonian age. The 

Niobrara in southeastern South Dakota consists largely 

of clayey limestone, and it disconformably overlies the 

Carlile (fig. 14). Both the lithology and basal contact of 

the Niobrara change northward. In northeastern North 

Dakota and southern Manitoba, the formation is composed of calcareous and noncalcareous shale, and it conformably overlies and grades into the Carlile and 

Morden (fig. 7). Most of the Niobrara in the Minnesota 

region is of open-marine and offshore-marine origin. 

However, in eastern South Dakota and adjacent areas, 

where the formation rests on the truncated Carlile, the 

basal Niobrara probably was deposited in nearshoremarine environments during a marine transgression. 

In conclusion, the Dakota, Graneros, and Greenhorn, 

which grade continuously upward from nonmarine sandstone to marine shale to marine limestone, apparently 

were deposited while the epicontinental sea was 
42 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

transgressing eastward. The strandline was oriented 

generally north-northeast. Shallow-marine and nonmarine strata of middle Cenomanian age, in the Dakota, 

crop out in the vicinity of Sioux City, Iowa. Shallowmarine and nonmarine strata of late Cenomanian age 

crop out in the Mesabi Range (Coleraine Formation) and 

near New Ulm, Minn. (unnamed sequence). The calcareous rocks of the Greenhorn in eastern South Dakota 

and adjoining areas were deposited in offshore-marine 

environments largely during the early Turonian. These 

rocks are probably represented by some of the shale encountered in boreholes near Richmond, in central Minnesota. Deposition of the Greenhorn was followed, 

without interruption, by deposition of the dominantly 

noncalcareous shale in the lower part of the Carlile, 

which reflects a marine regression in the Minnesota 

region in the middle Turonian. The Codell Sandstone 

Member of the Carlile, in eastern South Dakota, is of 

shallow-water, nearshore-marine origin and was 

deposited in the late middle Turonian during the same 

regression. Erosion of the top of the Carlile in eastern 

South Dakota may have begun in latest mid-Turonian 

time. The regression was followed by a marine transgression and deposition of shale in the upper part of the 

Carlile and the calcareous strata in the Niobrara during 

the late Turonian and Coniacian. 

Marine invertebrate fossils of Turonian, Coniacian, 

and Santonian Ages (fig. 7, zones 13-26) have been 

found in glacial deposits at scattered localities in 

southern Minnesota, northern Iowa, and western and 

northeastern Illinois (Chap. A, this volume; Woodward 

and Thomas, 1895). Many of these fossils were collected 

in areas where Cretaceous strata of marine origin have 

not been recognized or where the age of the local 

Cretaceous beds seems significantly different than the 

age of the fossils. Obviously, the anachronous fossils 

were transported southward by glacial activity probably 

from outcrops as far north as northern Minnesota, U.S., 

and Manitoba and Ontario, Canada. The areal distribution and ages of these fossils can be interpreted as 

evidence that lower Upper Cretaceous strata of marine 

origin were present in a region in northern Minnesota, 

northern Wisconsin, northern Michigan, and Ontario 

prior to the Pleistocene. Furthermore, the diverse species 

from the glacial deposits represent a relatively continuous sequence of marine beds in the Carlile and 

Niobrara. In western Greenland, Birkelund (1965) 

described late Turonian, Coniacian, and Santonian molluscan species, which have also been collected from outcrops of the Carlile and Niobrara and from glacial drift 

in the Minnesota region. The similarity of the fauna at 

these widely separated localities is convincing evidence 

of a direct seaway between the two regions (fig. 15), as 

Williams and Stelck (1975, p. 10-12) postulated, at least 

during the late Turonian, Coniacian, and Santonian. 

500 1000 KILOMETERS 

FIGURE 15.-Approximate distribution of land and sea in North 

America during Coniacian time (modified from Williams and 

Stelck, 1975, text fig. 5). 

STRUCTURE 

The structure of the lower Upper Cretaceous formations in the Minnesota region is best depicted by a 

structure-contour map of the top of the Greenhorn (fig. 

16). Throughout the western part of the region, the 

Greenhorn seems to be the same age and is recognizable 

at outcrops and in boreholes. Altitudes for the structure 

map were obtained mainly from geophysical logs of 

boreholes and from reports by Bolin and Petsch (1954), 

Schoon (1968), Klausing (1966), Kelly (1968), Downey 

(1973), Hutchinson (1973), Armstrong and Luttrell 

(1978), and Armstrong (1979). In northeastern South 

Dakota and eastern North Dakota, the Greenhorn forms 

a syncline that has a north west-trending axis and 

plunges northwest into the Williston Basin. The formation in northeastern Nebraska forms a syncline that has 

a southwest-trending axis and plunges southwest. These 

folds are separated by the Sioux uplift, a west-trending 

anticlinal feature. The structural relief on the top of the 

Greenhorn is at least 250 m between northeastern Minnesota and eastern North Dakota, and at least 200 m 

between northwestern Iowa and northeastern Nebraska 

(fig. 16). 
ggo 

LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 

98" 

\ 

~ 

ONTARIO 

/ 

I 

~ 

/ 

Duluth/ 

c;..,., 

r 

I 

I 

,) 

91" 

Rich ond AftsQ'/& / W I S C 0 N S I N 

0 Ukh~ld "'"'\ I 

) In neapolis o ST rAUL 

"'--"~~ ''\ 

0 Rochesle>' ~ 1 

-~~~1ington-----------------~ I 

EXPLANATION ..._ I 

.4 SELECT BOREHOLE- Number indicates borehole described in 

Table 1 

SELECT OUTCROP- Letter indicates outcrop described in 

Table 2 

----x LOCATION OF CROSS SECTION A-C (FIG. 17) 

--350- STRUCTURE CONTOUR-Contour 

interval 50 m. Queried 

where location uncertain 

--~- TRACE OF ANTICLINAL AXIS 

~ 

~ --

0

t--- TRACE OF SYNCLINAL AXIS J 

Omahao> ---=u-- FAULT-U, upthrown side; D. down11 o '---=--Z..-L---L----<~...1.L.::.._ _ _J_ __ ___j_ t ....____ __,__ thro_w_Ln_s_id_e ___ ___! ______ _,_ __ . __ 

0 100 200 KILOMETERS 

0 50 100 MILES 

FIGURE 16.-Structures at the top of the Greenhorn Formation in the Minnesota region. 

43 
44 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

Evidence of regional crustal deformation was also 

derived from mines and quarries (fig. 8) where fossiliferous beds of Cretaceous age rest on rocks of 

Precambrian age, from fossiliferous outcrops, and from 

cores where the depth and age of formations has been established. Cenomanian species of zone 8 (fig. 7) in the 

Coleraine Formation, which rests on Precambrian rocks 

in the Mesabi Range, occur at an altitude of about 390m 

(fig. 17). Strata of about the same age in excavations 

near Springfield, in southwest Minnesota, are at an 

altitude of 314 m. In northwestern Iowa at borehole 1 

(fig. 17), fossils of zone 8 in the Graneros Shale were 

cored at an altitude of about 340m. At nearby outcrops 

along the Big Sioux River, these species were collected at 

an altitude of approximately 370 m. Younger fossils, 

from the Greenhorn and Carlile Formations, were obSOUTHWEST 

A 1 2 B 

ME;;~sj..-ss km 140 km 105 km 75 km 

500 

300 

200 p£r 

100 

"'· 

tained from quarries and outcrops near Odessa and 

Browns Valley in western Minnesota. The Greenhorn 

(fig. 7, zones 10- 12) in this area locally overlies 

Precambrian rocks and is at an altitude of about 300 m. 

Exposures of fossiliferous Carlile (fig. 7, zone 13) are at 

an altitude of approximately 320m. The structural relief 

between strata of Graneros age in the Mesabi Range and 

younger strata in the Greenhorn near Odessa is at least 

90 m. 

In northeastern South Dakota near Browns Valley, 

Minn., the structure-contour lines (fig. 16) are interpreted as indicating locally steep dips and a northnortheast-trending normal fault. Beds on the west side of 

this hypothetical fault are approximately 60 m lower 

than the same beds on the east side of the fault. Shurr 

(1979) reported that outcrops of the Greenhorn about 8 

NORTHEAST 

3 4 5 6 7 8 9 c 

'I' ~~ 'I' :~ 'I' 75 km -·~~~· -,:-:::.....-+•l+l•-- 105 km t :~ r~·l 

p£r 

GREAT LAKES 

TECTONIC ZONE 

EXPLANATION 

QUATERNARY 

~ Glacial and alluvial 

deposits 

UNCONFORMITY 

UPPER CRETACEOUS 

~ P erre Shale 

~ Niobrara Formation 

UNCONFORMITY 

~ Carlile Shale 

~ Greenhorn Formation 

~ Graneros Shale EJ 

0 Dakota Formation 

UNCONFORMITY 

~ Paleozoic rocks 

UNCONFORMITY 

~ Precambrian rocks 

Coleraine 

Formation 

--?-- FORMATION BOUNDARY-Queried 

where location uncertain 

~- ~- UNCONFORMITY-Queried where 

location uncertain 

• 24 FOSSIL COLLECTION-Number indicates occurrence of a fossil that 

represents a numbered fossil 

zone listed in r igure 7 

u ---;..0-- FAULT -U. upthrown side; D. downthrown side 

FIGURE 17 .-Cross section showing structure of Upper Cretaceous formations in northwestern Iowa, northeastern South Dakota, and Minnesota. 

Locations of outcrops A-C and boreholes 1-9 shown in figure 6 and listed in tables 1 and 2. At locality A is a composite section of an 

outcrop. Fossil collections depicted near borehole 3 are from outcrops (altitude 300m) near Browns Valley, Minn. 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 45 

km north of Browns Valley (table 2, outcrop E), on the 

east side of the fault, strike N. 70° W. and dip 27° NE. 

He also noted that these outcrops are within the Great 

Lakes tectonic zone (figs. 16, 17) of Sims, Card, Morey, 

and Peterman (1980), which trends southwest through 

this area. The zone separates dissimilar crustal bodies of 

Precambrian age and probably has been the loci of intermittent tectonism since Archean time. Sims, Card, 

Morey, and Peterman (1980) suggested that minor 

faulting had occurred along the zone during Late 

Cretaceous or Cenozoic time. However, the unusual attitude of the outcropping Greenhorn near Browns Valley 

could have been caused either by local tectonism or by 

the lateral pressure of an advancing Pleistocene ice 

sheet. If the dip and elevation of the outcrop have been 

increased by glacial activity, little supporting evidence 

would remain for the fault in northeastern South Dakota 

that is shown in figures 16 and 17. 

Deformation during early Late Cretaceous time is indicated by the stratigraphy of the Carlile and Niobrara 

Formations. In eastern South Dakota, the Carlile ranges 

in thickness from less than 40 m on the Sioux uplift to 

more than 80 m near Aberdeen and along the Missouri 

River, on the northwest and southwest flanks of the uplift, respectively (fig. 12). At outcrops in southeastern 

South Dakota, middle Turonian shale in the Carlile is 

disconformably overlain by upper Coniacian limestone 

of the Niobrara (figs. 7, 14). Georgesen (1931, p. 31) and 

Simpson (1960, p. 20) reported that the Carlile-Niobrara 

contact has as much as 60 em of local relief. The top of 

the Carlile in this area evidently is an eroded surface 

(Hattin, 1975), which largely reflects tectonism during 

the late Turonian. 

In eastern North Dakota, the Carlile thickens 

westward from less than 80 m to more than 120m (fig. 

12) but apparently was not truncated during the 

Cretaceous. At outcrops along the Pembina River, shale 

of latest Turonian and Coniacian age in the upper part of 

the Carlile grades into calcareous shale of late Coniacian 

age in the overlying Niobrara. Nearby, in southern 

Manitoba, the Morden Shale of middle Turonian 

through Middle Coniacian age is conformably overlain 

by the Niobrara Formation of late Coniacian and Santonian age (McNeil and Caldwell, 1981). Furthermore, 

mollusks found in the Pleistocene drift of southern Minnesota, northern Iowa, and western Illinois (Chapter A, 

this volume), form most of the fossil succession for midTuronian through mid-Coniacian time. Some of the 

specimens represent fossil zones that have not been 

recognized at outcrops in southern Minnesota and 

eastern South Dakota. Presumably, many of these fossils 

were transported southward by glacial action from an 

uninterrupted sequence of Cretaceous strata in northern 

Minnesota and adjoining areas. The presumed absence 

of truncation of the Carlile and the westward thickening 

and westward dip (fig. 16) of the formation in eastern 

North Dakota probably indicate that the area was subsiding progressively westward during part of Turonian 

and Coniacian time. 

From these data it can be. concluded that Minnesota 

and northwest Iowa and eastern parts of North Dakota, 

South Dakota, and Nebraska were subjected to minor 

differential tectonism during the early Late Cretaceous. 

Structural deformation during the late Turonian 

probably caused truncation of part of the Carlile Shale 

in southeastern South Dakota and adjacent areas and, 

perhaps, the westward thickening of the Carlile in 

eastern North Dakota. Moreover, the local thickening of 

the Carlile in the southwest-trending area in 

northeastern South Dakota, along the strike of the Great 

Lakes tectonic zone (Sims and others, 1980) and in the 

northwest-trending area along the Missouri River, 

probably indicates that some of the Cretaceous deformation is related to fault zones in the underlying 

Precambrian rocks. 

In a study of the Cretaceous strata in Colorado and adjoining States, Weimer (1978) concluded that regional 

variations in the thickness of the Carlile and Niobrara 

indicate tectonic movement of the Transcontinental 

arch (fig. 18) during mid-Cretaceous time. From 

northeastern Colorado, the Transcontinental arch trends 

northeast, crosses southeastern South Dakota at or near 

the Sioux uplift, and extends into Minnesota. The 

westward thickening of the Carlile in eastern North and 

South Dakota and the truncation of the Carlile on the 

Sioux uplift are evidence of structural deformation during the Turonian and may also reflect tectonism along 

the arch. 

MARINE REGRESSIONS AND 

TRANSGRESSIONS IN THE 

MINNESOTA REGION 

COMPARED WITH THOSE IN 

WYOMING 

The lower Upper Cretaceous formations in the Minnesota region were deposited near the eastern shore of an 

epicontinental sea; whereas, formations of the same age 

in Wyoming were deposited near the western shore of the 

sea (fig. 15) (Reeside, 1944, maps 3-7). At outcrops on 

the east side of the Powder River Basin near Osage, Wyo. 

(fig. 18), the strata are named, in ascending order, Belle 

Fourche Shale, Greenhorn For.mation, Carlile Shale, and 

Niobrara Formation (fig. 19). The Carlile is composed of, 

from oldest to youngest, the Pool Creek Member, Turner 

Sandy Member, and Sage Breaks Member. Near Osage, 

the sequence of Belle Fourche, Greenhorn, Carlile, and 

basal Niobrara is about 370m thick (Merewether, 1980). 

The Belle Fourche consists mainly of noncalcareous 

shale and was deposited in offshore-marine environments. These strata locally grade into the calcareous 
46 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

__ -A L BE R T A / SA S KAT CHEw AN 1

1 o Treherne jl '\ ------L__ CANADA MANITOBA \ ONTARIO uNiTiD-STA"T'Esl ____ ------~-- ~ ..... /'~ 

------1 

UTAH 

MONTANA 

J<emmerer 

I 

I 

I ------------ --------

I : f'-\..../ .... -

1 Grand Forks~ 

I ' I NORTH DAKOTA I 

I BISMARCK \ 

I o \ 

~-----------------~ l Mi\ban~'l I SOUTH DAKOTA \ 

~apid City 0 

PIERRE 

KANSAS 

MINNESOTA /" 

~ Minneapolis 0 IW IS C 0 N SIN 

" "" ..... , 

--~-__1 ---- urr:e ') 

Springs\_ 

0 Waterloo 

IOWA 

MISSOURI 

-------- 1 00 200 300 400 500 KILOMETERS 

FIGURE 18.-The Minnesota region and States of the Central Rocky Mountains, showing locations of the Powder River Basin and the 

Transcontinental arch. 

shale and limestone of the overlying Greenhorn, which 

was deposited in offshore-marine and open-marine environments. Lime~tone at the top of the Greenhorn is 

conformably overlain by the silty shale in the Pool Creek 

Member of the Carlile. The Pool Creek is of offshoremarine origin and is disconformably overlain by the 

basal sandstone bed of the Turner Sandy Member. 

Sandstone, siltstone, and shale of the Turner were 

deposited mainly in shallow-marine environments near 

the seaward terminus of a delta. These rocks are conformably overlain by the slightly calcareous shale of the 

Sage Breaks Member of the Carlile. ·Most of this member 

accumulated in offshore-marine environments. The Sage 

Breaks is disconformably overlain by the Niobrara Formation, which includes a basal unit of calcareous and 

noncalcareous shale of open-marine and offshore-marine 

origin. 

In the southwestern part of the Powder River Basin 

near Casper, Wyo. (fig. 18), lower Upper Cretaceous 

strata are assigned to the Frontier Formation and the 

lower part of the overlying Cody Shale (fig. 19). Locally, 

the Frontier is composed of, from oldest to youngest, the 

Belle Fourche Member, unnamed member, and Wall 

Creek Member; and the lower part of the Cody includes 

the Sage Breaks Member and the overlying Niobrara 

Member. This sequence ie commonly about 360m thick. 

The Frontier consists largely of interstratified shale, siltstone, and sandstone of shallow-marine origin. In the 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 47 

w Area of Sioux Osage area, Casper area. v Informal < E- substage (/) 

Western Interior fossil-zones' City, Iowa, and 

Vermillion, S. Oak. 

northeastern northeastern 

Wyoming' Wyoming 

Kemmerer area. 

southwestern 

Wyoming 

~ 26 ·= 

~ Lower 25 

Clioscaphites saxitonianus 

Scaphites depressus 

Niobrara 

Formation 

Niobrara 

Member 

Hilliard 

Shale 

(lower 

part) (/) 

~ Upper 

·~ Middle 

-~ 

c3 Lower 

Upper 

~ 

·:: 

2 

E-" Middle 

24 

2:l 

22 

21 

20 

19 

18 

li 

16 

15 

14 

1:3 

12 

Scaphites ventricosus 

Inoceramus deformis 

Inoceramus erectus 

Inoceramus waltersdorfensis 

Prionocyclus quadratus 

Scaphites niwicollensis 

Scaphites whit{ieldi 

Scaphites warreni 

Prioncn:vclus macom bi 

Prionocyclus hyatti 

Subprionocyclus percarinatus 

Colli#noniceras u•oollJ?ari re#ulare 

Colli#noniceras wooll#ari woollgari 

Member 

Dry 

Hollow 

Member" 

Mbr. 

Greenhorn Allen Hollow Mbr." 

Lower II Mammites nodosoide., 

10 Watinoceras coloradoeme Formation Coalville Mbr.' 

9 Scipunoceras J?,racile 

Upper 8 DunueJ?anoceras a/ bertense Graneros Greenhorn 

Shale Formation 

/Junt'e#anucera., pondi 

~ 6 Plesiacanthoceras u-yomingense 

·:: 5 Acanthoceras amphibolum 

E "" Acanthoceras alvaradoense 0 Middle Dakota Belle 

Chalk 

Creek 

Acanthoceras mu/doonense ~ 

u A canthoceras 11ranerosense Formation Fourche 

Belle 

Fourche 

. Member 

Member" 

I Calycoceras gilberti -- ? 

Lower No molluscan fossil record 

'Numbers representing some zones are shown in figure 17 and noted in text. 

'Age of basal contact of Niobrara Formation from Evetts (1976. p. 121). 

"'Myers (19ii). 

Shale 

FIGURE 19.-Correlation of the lower Upper Cretaceous formations at localities in the Minnesota region and in Wyoming. Hiatus in sequence 

patterned. Age of contacts with queries is estimated. 

lower part of the Cody, the Sage Breaks and Niobrara 

are composed mainly of noncalcareous shale and 

calcareous shale, respectively, and were deposited in 

offshore-marine environments. Unconformities have 

been confirmed at the base and top of the unnamed 

member of the Frontier and, in the southern part of the 

basin near Douglas (fig. 18), at the base of the Niobrara 

(Merewether and others, 1979, p. 91-95). 

Strata of mid-Cretaceous age in northwestern Wyoming are also included in the Frontier Formation and the 

lower part of the Cody Shale. In the vicinity of Cody, 

Wyo. (fig. 8), the Frontier is composed of three unnamed 

members, each of which is disconformable with the adjacent member (Merewether and others, 1975). At Cody, 

the outcropping Frontier is about 180m thick and consists of interbedded shale, siltstone, and sandstone, and 

minor conglomerate, coal, and bentonite. These rocks 

were deposited in several nearshore-marine and deltaic 

environments. The lower part of the Cody Shale in this 

area consists of shale that accumulated mainly in 

offshore-marine environments. 

In southwestern Wyoming near Kemmerer (fig. 18), 

the lower Upper Cretaceous strata are at least 660 m 

thick and are included in the Frontier Formation and in 

the lower part of the overlying Hilliard Shale (Cobban 

and Reeside, 1952). Myers (1977) divided the Frontier in 

that area into five members which are called, in 

ascending order, the Chalk Creek, Coalville, Allen Hollow, Oyster Ridge Sandstone, and Dry Hollow (fig. 19). 

The member names were previously applied to rocks at 

Coalville, in northeastern Utah (fig. 18), by Hale (1960, 

1962) and Ryer (1977). In Wyoming, the Chalk Creek 

Member consists largely of shale, siltstone, and sandstone of nonmarine origin. The Coalville Member conformably overlies the Chalk Creek and is composed mainly 

of shallow-marine sandstone and shale. Conformably 

overlying the Coalville is the Allen Hollow Mem her, 

which consists of offshore-marine shale. The Oyster 

Ridge Sandstone Member conformably overlies the Allen Hollow and was deposited in shallow-marine environments. Sandstone of the Oyster Ridge is overlain by 

the Dry Hollow Member, which is composed of nonmarine rocks and a shallow-marine sandstone at the top. 

Hale (1962) suggested that the contact of the Oyster 

Ridge and the Dry Hollow is a disconformity and that 

the Dry Hollow is early Coniacian in age. Myers (1977) 
48 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

reported that the members are conformable and that the 

Dry Hollow is Turonian. The marine sandstone at the 

top of the Frontier is conformably overlain by offshoremarine shale of the Hilliard Shale. 

The upper part of the Dakota Formation, the Graneros 

Shale, and the Greenhorn Formation near Sioux City, 

Iowa, are a sequence of Cenomanian and Turonian beds 

that grade from nonmarine sandstone at the base, 

through marine sandstone and offshore-marine shale, to 

open-marine limestone at the top. These strata were 

deposited continuously while the sea was transgressing 

eastward across a terrane of Paleozoic and Precambrian 

rocks (fig. 20). The sequence is the same age as the Belle 

Fourche Shale and overlying Greenhorn Formation of 

northeastern Wyoming, which also include noncalcareous shale and overlying calcareous beds. Most of 

these strata are represented on the west flank of the 

Powder River Basin by the Belle Fourche Member of the 

Frontier (fig. 19). In this basin, the areal distribution of 

the youngest discrete body of sandstone in the member is 

significantly less than the areas of the older bodies of 

sandstone. This uppermost sandstone was deposited in 

late Cenomanian (Greenhorn) time; consequently, the 

comparatively small lateral extent of the body may 

reflect a marine transgression (Merewether and others, 

1979, p. 95). In northwestern Wyoming at Cody, most of 

the beds of Greenhorn age are represented by an unconformity. Better evidence of a transgression can be obr&:l Pembina c Informal Western Interior fossil-zones River area, 

~ substage N. Oak. 

c: 

~ Ill '§ Lower Clioscaphites saxitonianus i:! 

Ill Scaphites depressus 

~ '.ll 

c Upper Scaphites ventricosus Ill 

-~ Middle Inoceramus defor.mis 

·a Lower Inoceramus erectus 0 

u Inoceramus waltersdorfensis ?-

Prionocyclus quadratus 

Upper Scaphites nigricollensis 

Scaphites whit{ieldi 

Scaphites warreni 

s:: Prionocyclus macombi Ill 

·a Prionocyclus hyatti ? e Middle Subprionocyclus percarinatus i :I 

E- Collignoniceras woollgari R regulare 

Collignoniceras woollgari woollgari 

Lower Mammites nodosoides 

Watinoceras coloradoense 

Sciponoceras gracile Upper Dunveganoceras albertense Dunveganoceras pondi 

Plesiacanthoceras wyomingeme 

-~ Acanthoceras amphibolum T c 

Ill Middle Acanthoceras alvaradoense 

~ Acanthoceras muldoonense c 

Ql Acanthoceras granerosense u Calycoceras gilberti t---?-

Lower No molluscan fossil record 

tained from outcrops of the Frontier in southwestern 

Wyoming, where nonmarine strata largely of Cenomanian Age in the Chalk Creek Member are overlain by 

marine strata mainly of early Turonian (late Greenhorn) 

age in the Coalville and Allen Hollow Members (Cobban 

and Reeside, 1952, fig. 2; Myers, 1977, fig. 2). The striking similarities in the ages of the transgressive-marine 

rocks on the east side of the Cretaceous seaway in North 

Dakota and Iowa and on the west side of the seaway in 

parts of Wyoming (fig. 20) can be interpreted as evidence 

of either continent-wide tectonic subsidence or the 

eustatic rise in sea level as suggested by Kauffman 

(1977, p. 89). 

Nevertheless, the sequences of mid-Cretaceous strata 

at Casper in northeastern Wyoming (fig. 19) and at Cody 

in northwestern Wyoming seem to indicate a different 

series of events (fig. 20). Shallow-marine beds of 

Cenomanian Age in the Belle Fourche Member of the 

Frontier near Casper were truncated during an early 

Turonian marine regression and were subsequently 

buried by similar beds in the unnamed member during a 

middle Turonian transgression. At Cody, nearshoremarine and deltaic strata of Cenomanian Age in the 

lower unnamed member of the Frontier were truncated 

during a marine regression in early or ·possibly middle 

Turonian time and are overlain by shallow-marine beds 

in the middle unnamed member, which were deposited 

during a late middle Turonian transgression. However, 

Sioux City Osage Casper Cody Kemmerer 

area, area, area, area, area, 

Iowa Wyoming Wyoming Wyoming Wyoming 

~ 

~ 

1 1 If I ? 

If I T I 

I I ? 

? 

R ? 

? li"l 

It I 

i ? ? 

~ R I 1 

~ I ~ 

If I 

? ? 

? T 

FIGURE 20.-Diagram of marine transgressions (T) and regressions (R) of mid-Cretaceous age, interpreted from strata at localities in the 

Minnesota region and in Wyoming. Queried where data inadequate. 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 49 

the apparent differences between the geologic history of 

these strata and of the sequences near Osage or Kemmerer were probably caused by intermittent local tectonism and by the alternating local erosion and deposition common in deltaic environments. 

In eastern South Dakota and contiguous areas, 

limestone in the Greenhorn is conformably overlain by 

calcareous shale and noncalcareous shale of the Carlile, 

which includes sandstone of the Codell Member at or 

near the top. Disconformably overlying the Carlile is 

limestone of the Niobrara. The Carlile is of middle Turonian age; the Codell is probably of late middle Turonian 

age; the disconformity represents part of the middle 

Turonian, the late Turonian, and the early and middle 

Coniacian; and the lower part of the Niobrara is of late 

Coniacian and Santonian age (fig. 19). In northeastern 

North Dakota, the Carlile probably is of middle Turonian through middle Coniacian age, the Codell is absent, 

and the disconformity apparently is not present (fig. 7). 

These two sequences reflect a marine regression of mid--

dle Turonian age, which may have caused truncation of 

part of the Carlile in eastern South Dakota, and a subsequent transgression of late Turonian through middle 

Coniacian age (fig. 20), which culminated in deposition 

of the basal Niobrara. 

These events and others may be recorded in 

northeastern Wyoming by the Greenhorn, Carlile, and 

Niobrara, on the east flank of the Powder River Basin, 

and by the Frontier and Cody on the southwest flank of 

the basin (figs. 19, 20). The contrasting lithologies of the 

Greenhorn and Pool Creek and the disconformity at the 

top of the Pool Creek indicate a marine regression during 

the middle Turonian. This regression was accompanied 

by deposition of the unnamed member of the Frontier 

during a local transgression near Casper, but the regression then evidently caused the erosion surface at the top 

of the unnamed member. The Turner and Sage Breaks 

Members of the Carlile on the east side of the Powder 

River Basin and the Wall Creek Member of the Frontier 

and the Sage Breaks Member of the Cody in the 

southwestern part of the basin represent a marine 

transgression, which continued through late Turonian 

and much of Coniacian time. A small hiatus at the Sage 

Breaks-Niobrara contact near Osage may indicate submarine erosion in the late Coniacian. In the southern 

part of the basin in the vicinity of Douglas, a disconformity at the base of the Niobrara indicates erosion in 

lower or middle Coniacian time. In that area, the period 

of erosion was succeeded by deposition of fossiliferous 

calcareous shale and limestone (fig. 19, zone 24), in the 

Niobrara. 

In northwestern Wyoming at Cody (fig. 18), the lower 

unnamed member of the Frontier is of Cenomanian age 

and largely of shallow-marine and deltaic origin 

(Merewether and others, 1975). This sequence is disconformably overlain by rocks of late middle Turonian age 

and shallow-marine origin in the middle unnamed 

member of the Frontier. The disconformity and the middle mem her represent a marine regression in the early or 

early middle Turonian and a subsequent marine 

transgression in the late middle Turonian, respectively. 

Resting disconformably on the middle member, the upper unnamed member of the Frontier consists largely of 

deltaic and nearshore-marine sandstone of early and 

probably middle Coniacian age. These rocks are conformably overlain by marine shale of middle Coniacian age 

in the lower part of the Cody Shale. The disconformity at 

the base of the upper member of the Frontier probably 

reflects a marine regression in the late Turonian. A 

marine transgression during early and middle Coniacian 

time is represented by the upper member of the Frontier 

and the overlying Cody. 

In the Frontier Formation in southwestern Wyoming, 

lower Turonian sandstone and shale of the Coalville 

Member and lower and middle Turonian shale in the 

overlying Allen Hollow Member indicate a marine 

transgression during early Turonian time (fig. 20). A 

marine regression in· the middle Turonian is represented 

by the upper part of the Allen Hollow Member, the 

Oyster Ridge Sandstone Member, and the lower part of 

the Dry Hollow Member. The nonmarine strata and 

overlying marine sandstone in the upper part of the Dry 

Hollow Member of the Frontier, and the marine shale in 

the overlying Hilliard Shale were deposited during a 

marine transgression, which probably began in late 

Turonian time and continued, at least, into the early 

Coniacian. In northern Utah, at Coalville, the upper part 

of the Frontier Formation includes a marine shale and an 

overlying marine sandstone of middle Coniacian age 

(Trexler, 1966, p. 34-37). The marine regression indicated by these rocks has been described by Ryer (1977, 

p. 110). 

In summary, the Coalville Member and the lower part 

of the Allen Hollow Member of the Frontier in 

southwestern Wyoming and the upper part of the 

Greenhorn Formation in northeastern Wyoming and in 

eastern South Dakota were deposited in early Turonian 

time during a major transgression (fig. 20). Early Turonian regressions recorded by unconformities at Casper 

and Cody, Wyo., were local events. The upper part of the 

Allen Hollow and the entire Oyster Ridge Sandstone 

Member in southwestern Wyoming are correlative with 

lower parts of the Pool Creek Member of the Carlile in 

the Powder River Basin and the Carlile of eastern South 

Dakota. These strata and the unconformity at the top of 

the unnamed member of the Frontier at Casper probably 

reflect the same important middle Turonian regression. 

The middle unnamed member of the Frontier at Casper 

and at Cody represents local subsidence and local 

transgressions in the middle Turonian. 
50 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

The upper part of the Dry Hollow Member of the Frontier and the lower part of the overlying Hilliard in 

southwestern Wyoming, the upper member of the Frontier and the lower part of the overlying Cody in 

northwestern Wyoming, the Wall Creek Member of the 

Frontier and overlying Sage Breaks and Niobrara 

Members of the Cody, and the Turner Member and 

overlying Sage Breaks Mem her of the Carlile in 

northeastern Wyoming, can be correlated with the upper 

part of the Carlile and the overlying Niobrara in 

northeastern North Dakota. These strata were deposited 

in late Turonian and Coniacian time during a major 

transgression (fig. 20). The late Turonian regression 

represented by the unconformity at the base of the upper 

member of the Frontier in northwestern Wyoming 

probably indicates uplift in that area. Furthermore, a 

marine regression of about middle Coniacian age, which 

could be reflected by the unconformity at the base of the 

Niobrara in the southern part of the Powder River Basin 

and is represented by middle Coniacian strata in 

northern Utah (Trexler, 1966, p. 37), may also represent 

local tectonism. 

In conclusion, the Cenomanian and early Turonian 

transgression of Greenhorn time, the middle Turonian 

regression of early Carlile time, and the late Turonian 

and Coniacian transgression of upper Carlile and 

Niobrara time clearly are continent-wide events similar 

to those described by Hancock and Kauffman (1979, fig. 

4). Some of the other transgressions and regressions were 

probably caused by mid-Cretaceous structural deformation and by changes in the source and supply of sediments during deposition. Local hiatuses may also reflect 

erosion of sediments by submarine currents. Hancock 

and Kauffman (1979) concluded that the major 

transgressions and regressions in the mid-Cretaceous 

were controlled by increases and decreases in the elevation of sea level. However, Hays and Pitman (1973) and 

Pitman (1978) indicated that sea level was rising continuously, although at varying rates, during this time 

(about 88-96 million years before present). Furthermore, 

Pitman (1978, p. 1389) proposed that transgressive and 

regressive "events may be caused by changes in the rates 

of sea-level rise." 

REFERENCES CITED 

Agnew, A. F., and Tychsen, P. C., 1965, A guide to the stratigraphy of 

South Dakota: South Dakota State Geological Survey Bulletin 

14, 195 p. 

Allison, I. S., 1932, The geology and water resources of northwestern 

Minnesota: Minnesota Geological Survey Bulletin 22, 245 p. 

Andrews, G. W., 1958, Windrow Formation of upper Mississippi valley 

region, a sedimentary and stratigraphic study: The Journal of 

Geology, v. 66, p. 597-624. 

Armstrong, C. A., 1979, Ground-water basic data for Ransom and 

Sargent Counties, North Dakota: North Dakota Geological 

Survey Bulletin 69, pt. 2, 637 p. 

Armstrong, C. A., and Luttrell, S. P., 1f}78, Ground-water basic data 

for Dickey and LaMoure Counties, North Dakota: North Dakota 

Geological Survey Bulletin 70, pt. 2, 557 p. 

Arndt, B. M., 1975, Geology of Cavalier and Pembina Counties: North 

Dakota Geological Survey Bulletin 62, pt. 1, 68 p. 

Austin, G. S., 1963, Geology of clay deposits Red Wind area, Goodhue 

and Wabasha Counties, Minnesota: Minnesota Geological 

Survey Report of Investigations 2, 23 p. 

__ 1970, Weathering of the Sioux Quartzite near New Ulm, Minnesota, as related to Cretaceous climates: Journal of Sedimentary Petrology, v. 40, no. 1, p. 184-193. 

__ 1972, Precambrian Sioux Quartzite and Cretaceous rocks of 

southern Minnesota, in Field trip guidebook for Paleozoic and 

Mesozoic rocks of southeastern Minnesota: Minnesota Geological 

Survey and University of Minnesota Guidebook Series No. 4, p. 

55-63. 

Bain, H. F., 1895, Cretaceous deposits of the Sioux Valley: Iowa 

Geological Survey, v. 3, p. 99-114. 

__ 1896, Geology of Woodbury County, Iowa: Iowa Geological 

Survey, v. 5, p. 241-299. 

Baker, C. H., Jr., 1967, Geology and ground water resources of 

Richland County: North Dakota Geological Survey Bulletin 46, 

pt. 1, 45 p. 

Barkley, R. C., 1952, Artesian conditions in southeastern South 

Dakota: South Dakota Geological Survey Report of Investigations 71, 71 p. 

Bergquist, H. R., 1944, Cretaceous of the Mesabi iron range, Minnesota: Journal of Paleontology, v. 18, no. 1, p. 1-30. 

Birkelund, Tove, 1965, Ammonites from the upper Cretaceous of west 

Greenland: Meddelelser om Gr¢nland, v. 179, no. 7, Copenhagen, 

192 p. 

Bluemle, J. P., 1973, Geology of Nelson and Walsh Counties, North 

Dakota: North Dakota Geological Survey Bulletin 57, pt. 1, 70 p. 

Bolin, E. J., 1956, Upper Cretaceous foraminifera, ostracoda, and 

radiolaria from Minnesota: Journal of Paleontology, v. 30, no. 2, 

p. 278-298. 

Bolin, E. J ., and Petsch, B. C., 1954, Well logs in South Dakota east of 

Missouri River: South Dakota Geological Survey Report of 

Investigations 75, 95 p. 

Burchard, E. F., 1904, Geology of Dakota County, Nebraska, with 

special reference to the lignite deposits: Sioux City Academy of 

Science and Letters, Proceedings v. 1, p. 135-184. 

Caldwell, W. G. E., North, B. R., Stelck, C. R., and Wall, J. H., 1978, 

A foraminiferal zonal scheme for the Cretaceous System in the 

Interior Plains of Canada, in C. R. Stelck, and B. D. E. Chatterton, eds., Western and Arctic Canadian biostratigraphy: The 

Geological Association of Canada Special Paper 18, p. 495-575. 

Calvin, Samuel, 1893, The relation of the Cretaceous deposits of Iowa 

to the subdivisions of the Cretaceous proposed by Meek and 

Hayden: Iowa Academy of Sciences Proceedings, v. 1, pt. 3, p. 

7-12. 

Capellini, J. and Heer, 0., 1866, Les phyllites cretacees du Nebraska: 

Societe Helvetique des Sciences Naturelles, Nouveau Memoir 22, 

22 p. 

Cobban, W. A., and Reeside, J. B., Jr., 1952, Frontier Formation, 

Wyoming and adjacent areas: American Association of 

Petroleum Geologists Bulletin, v. 36, no. 10, p. 1913-1961. 

Condra, G. E., 1908, Geology and water resources of a portion of the 

Missouri River Valley in northeastern Nebraska: U.S. Geological 

Survey Water-Supply Paper 215, 59 p. 

Darton, N. H., 1909, Geology and underground waters of South 

Dakota: U.S. Geological Survey Water-Supply Paper 227, 156 p., 

.15 pls. 

Downey, J. S., 1973, Ground-water basic data for Griggs and Steele 

Counties, North Dakota: North Dakota Geological Survey Bulletin 64, pt. 2, 468 p. 
LOWER UPPER CRETACEOUS STRATA, MINNESOTA, ADJACENT AREAS 51 

Evetts, M. J ., 1976, Microfossil biostratigraphy of the Sage Breaks 

shale (Upper Cretaceous) in northeastern Wyoming: The Mountain Geologist, v. 13, no. 4, p. 115-134. 

Georgesen, N. C., 1931, The stratigraphy of the Colorado Group of 

northeastern Nebraska and adjacent areas: Master of Science 

thesis, State University of Iowa, Ames, 52 p. 

Gill, J. R., and Cobban, W. A., 1965, Stratigraphy of the Pierre Shale, 

Valley City and Pembina Mountain areas, North Dakota: U. S. 

Geological Survey Professional Paper 392-A, 20 p. 

Hale, L. A., 1960, Frontier Formation-Coalville, Utah, and nearby 

areas of Wyoming and Colorado in Overthrust Belt of 

southwestern Wyoming and adjacent areas: Wyoming Geological 

Association 15th Annual Field Conference Guidebook, p. 

136-146. 

___ 1962, Frontier Formation-Coalville, Utah, and nearby areas of 

Wyoming and Colorado in Symposium on Early Cretaceous rocks 

of Wyoming: Wyoming Geological Association 17th Annual Field 

Conference Guidebook, p. 211-220. 

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 Sciences 

Memoir, v. 5, p. 379-411. 

Hancock, J. M., and Kauffman, E. G., 1979, The great transgressions 

of the Late Cretaceous: Journal of the Geological Society, v. 136, 

p. 175-186. 

Hansen, D. E., and Kume, Jack, 1970, Geology and ground water 

resources of Grand Forks County: North Dakota Geological 

Survey Bulletin 53, 76 p. 

Hattin, D. E., 1975, Stratigraphic study of the Carlile-Niobrara (Upper 

Cretaceous) unconformity in Kansas and northeastern Nebraska, 

in W. G. E. Caldwell, ed., The Cretaceous System in the Western 

Interior of North America: The Geological Association of Canada 

Special Paper 13, p. 195-210. 

Hayden, F. V., 1876, Annual report of the U.S. Geological and 

Geographical Survey of the Territories, embracing Colorado and 

parts of adjacent territories, being a report of progress of the exploration for the year 1874, 515 p. 

Hays, J. D., and Pitman, W. C., Ill, 1973, Lithospheric plate motion, 

sea level changes and climatic and ecological consequences: 

Nature, v. 246, p. 18-22. 

Heer, Oswald, 1859, Descriptions of fossil plants from No. 1 of the 

Nebraska section (of Meek and Hayden): Philadelphia Academy 

of Natural Sciences Proceedings, v. 11, p. 265-266. 

Hutchinson, R. D., 1973, Ground-water basic data of Cavalier and 

Pembina Counties: North Dakota Geological Survey Bulletin 62, 

pt. 2, 606 p. 

Kauffman, E. G., 1977, Geological and biological overview: Western 

Interior Cretaceous basin: The Mountain Geologist, v. 14, nos. 3 

and 4, p. 75-99. 

Kelly, T. E., 1968, Geology and ground water resources of Grand Forks 

County: North Dakota Geological Survey Bulletin 53, 117 p. 

King, Clarence, 1876, Annual report upon the geological exploration of 

the fortieth parallel from the Sierra Nevada to the eastern slope 

of the Rocky Mountains; Atlas, 6 p. 

Klausing, R. L., 1966, Geology and ground water resources of Cass 

County, North Dakota: North Dakota Geological Survey Bulletin 

47, pt. 2, 158 p. 

Kloos, J. H., 1872, A Cretaceous basin in the Sauk Valley, Minnesota: 

The American Journal of Science and Arts, ser. 3, v. 3, p. 17-26. 

Koch, N. C., and Bradford, Wendell, 1976, Geology and water 

resources of Browrr County, South Dakota: South Dakota 

Geological Survey Bulletin 25, pt. 2, 53 p. 

Lanphere, M. A., and Jones, D. L., 1978, Cretaceous time scale from 

North America, in G. V. Cohee, M. F. Glaessner, and H. D. 

Hedberg, ed., Contributions to the geologic time scale: American 

Association of Petroleum Geologists Studies in Geology No. 6, p. 

259-268. 

Lesquereux, Leo, 1868, On some Cretaceous fossil plants from 

Nebraska: The American Journal of Science and Arts, ser. 2, v. 

46, p. 91-105. 

___ 1895, Cretaceous fossil plants from Minnesota: Minnesota 

Geological Survey, Final Report, v. 3, pt. 1, p. 1-22. 

Lindholm, G. F., Oakes, E. L., Ericson, D. W., and Helgesen, J. 0., 

1972, Water resources of the Crow Wing River watershed, central 

Minnesota: U.S. Geological Survey Hydrologic Investigations 

Atlas HA-380. 

Ludvigson, Greg, and Bunker, Bill, 1978, Water resources test drilling 

program-northwest Iowa: Iowa Geological Survey Newsletter, v. 

1, no. 3, p. 8-9. 

Maclay, R. W., Winter, T. C., and Bidwell, L. E., 1968, Water 

resources of the Mustinka and Bois de Sioux Rivers watershed, 

west-central Minnesota: U.S. Geological Survey Hydrologic 

Investigations Atlas HA-272. 

McNeil, D. H., and Caldwell, W. G. E., 1981, Cretaceous rocks and 

their foraminifera in the Manitoba escarpment: The Geological 

Association of Canada Special Paper 21, 439 p. 

Marcou, Jules, 1864, Une reconnaissance geologique au Nebraska: 

Societe Geologique France, Bulletin, Ser. 2, v. 21, p. 132-146. 

Maximillian, A. P., 1839-1841, Reise in Das Innere Nord-America in 

den Jahren 1832 his 1835: Coblenz; v. 1, 653 p.; v. 2, 687 p.; v. 3, 

plates. 

Meek, F. B., 1865, Remarks on the Carboniferous and Cretaceous rocks 

of eastern Kansas and Nebraska: The American Journal of 

Science and Arts, ser. 2, v. 39, p. 157-174. 

Meek, F. B., and Hayden, F. V., 1862, Description of new Lower 

Silurian (Primordial), Jurassic, Cretaceous, and Tertiary fossils, 

collected in Nebraska Territory, with some remarks on the rocks 

from which they were obtained: Philadelphia Academy of 

Natural Sciences Proceedings, v. 13, p. 415-447. 

Merewether, E. A., 1980, Stratigraphy of lower Upper Cretaceous formations at drilling sites in Weston and Johnson Counties, 

northeastern Wyoming: U.S. Geological Survey Professional 

Paper 1186-A, 25 p. 

Merewether, E. A., Cobban, W. A., and Cavanaugh, E. Thomas, 1979, 

· Frontier Formation and equivalent rocks in eastern Wyoming: 

The Mountain Geologist, v. 16, no. 3, p. 67-102. 

Merewether, E. A., Cobban, W. A., and Ryder, R. T., 1975, Lower Upper Cretaceous strata, Bighorn Basin, Wyoming and Montana, in 

Geology and mineral resources of the Bighorn Basin: Wyoming 

Geological Association 27th Annual Field Conference Guidebook, 

p. 73-84. 

Merewether, E. A., and Gray, A. W., 1978, Status of mineral resource 

information for the Sisseton Reservation, South Dakota and 

North Dakota: U.S. Bureau of Indian Affairs Administrative 

Report BIA-44, 24 p. 

Moore, W. L., 1979, A preliminary report on the uranium geology of the 

Red River Valley drilling project, eastern North Dakota and 

northwestern Minnesota: U.S. Department of Energy (Bendix 

Field Engineering Company subcontract no. 77-059-E), 292 p. 

Morton, S. G., 1828, Geological observations on the secondary, tertiary, and alluvial formations of the Atlantic coast of the United 

States. Arranged from the notes of Lardner Vanuxem: 

Philadelphia Academy of Natural Sciences Journal, v. 6, p. 

59-71. 

___ 1834, Synopsis of the organic remains of the Cretaceous group of 

the United States: Philadelphia, 88 p. 

___ 1842, Description of some new species of organic remains of the 

Cretaceous group of the United States; with a tabular view of the 

fossils hitherto discovered in this formation: Philadelphia 

Academy of Natural Sciences Journal, v. 8, p. 207-;227. 
52 STRATIGRAPHY, PALEONTOLOGY, MID-CRETACEOUS, MINN. 

Myers, R. C., 1977, Stratigraphy of the Frontier Formation (Upper 

Cretaceous), Kemmerer area, Lincoln County, Wyoming, in 

Rocky Mountain Thrust Belt Geology and Resources: Wyoming 

Geological Association 29th Annual Field Conference Guidebook, 

p. 271-311. 

Newberry, J. S., 1860, Notes on the ancient vegetation of North 

America: The American Journal of Science and Arts, v. 29, p. 

208-218, and v. 30, p. 273-275. 

Nicollet, J. N., 1841, On the geology of the region on the Upper Mississippi and the Cretaceous Formation of the Upper Missouri: The 

American Journal of Science and Arts, v. 41, p. 180-182. 

Nuttall, Thomas, 1821, Geological structure of the valley of the Mississippi: Philadelphia Academy of Natural Sciences Journal, v. 2, p. 

14-52. 

Oakes, E. L., 1970, Geology and ground-water resources of the Grand 

Rapids area, north-central Minnesota: U.S. Geological Survey 

Hydrologic Investigations Atlas HA-322. 

Owen, D. D., 1852, Geological Survey of Wisconsin, Iowa and Minnesota, and incidentally a portion of Nebraska Territory: made 

under direction of U.S. Treasury Department, Philadelphia, 195 

p. 

Parham, W. E., 1970, Clay mineralogy and geology of Minnesota's 

kaolin clays: Minnesota Geological Survey Special Publication 

Series SP-10, 142 p. 

Pierce, R. L., 1961, Lower Upper Cretaceous plant microfossils from 

Minnesota: Minnesota Geological Survey Bulletin 42, 90 p. 

Pitman, W. C., III, 1978, Relationship between eustacy and 

stratigraphic sequences of passive margins: Geological Society of 

America Bulletin, v. 89, p. 1389-1403. 

Reeside, J. B., Jr., 1944, Maps showing thickness and general character 

of the Cretaceous deposits in the Western Interior of the United 

States: U.S. Geological Survey Oil and Gas Investigations 

Preliminary Map 10. 

Rice, D. D., 1977, Stratigraphic sections from well logs and outcrops of 

Cretaceous and Paleocene rocks, northern Great Plains, North 

Dakota and South Dakota: U.S. Geological Survey Oil and Gas 

Investigations Chart OC-72. 

Rodis, H. G., 1963, Geology and occurrence of ground water in Lyon 

County, Minnesota: U.S. Geological Survey Water-Supply Paper 

1619-N, 41 p. 

Ryer, T. A., 1977, Coalville and Rockport areas, Utah, in E. G. Kauffman, ed., Cretaceous facies, faunas, and paleoenvironments 

across the Western Interior basin: The Mountain Geologist, v.14, 

nos. 3 and 4, p. 105-128. 

Sardeson, F. W., 1908, Geological history of the Redstone quartzite: 

Geological Society of America Bulletin 19, p. 221-242. 

Schoon, R. A., 1965, Dakota Formation of South Dakota: South 

Dakota Academy of Science Proceedings, v. 44, p. 72-79. 

__ 1968, Selected formation tops in water wells logged by the South 

Dakota Geological Survey to January 1, 1968: South Dakota 

Geological Survey Circular 36, 28 p. 

__ 1971, Geology and hydrology of the Dakota Formation in South 

Dakota: South Dakota Geological Survey Report of Investigations 104, 55 p. 

Shurr, G. W., 1979, Upper Cretaceous rocks at Lake Traverse in 

western Minnesota: U.S. Geological Survey Open-File Report 

79-379, 9 p. 

Simpson, H. E., 1960, Geology of the Yankton area, South Dakota and 

Nebraska: U.S. Geological Survey Professional Paper 328. 

Sims, P. K., Card, K. D., Morey, G. B., and Peterman, Z. E., 1980, 

The Great Lakes tectonic zone-a major crustal structure in 

central North America: Geological Society of America Bulletin 

91, pt. 1, p. 690-698. 

Sloan, R. E., 1964, The Cretaceous System in Minnesota: Minnesota 

Geological Survey Report of Investigations 5, 64 p. 

Stauffer, C. R., and Thiel, G. A., 1941, The Paleozoic and related rocks 

of southeastern Minnesota: Minnesota Geological Survey Bulletin 29, 261 p. 

Steece, F. V., and Howells, L. W., 1965, Geology and ground water supplies in Sanborn County, South Dakota: South Dakota 

Geological Survey Bulletin 17, 182 p. 

Tester, A. C., 1931, The Dakota Stage of the type locality: Iowa 

Geological Survey Annual Report, v. 35, p. 195-332. 

Thiel, G. A., 1944, The geology and underground waters of southern 

Minnesota: Minnesota Geological Survey Bulletin 31, 506 p. 

___ 1947, The geology and underground waters of northeastern Minnesota: Minnesota Geological Survey Bulletin 32, 247 p. 

Thwaites, F. T., and Twenhofel, W. H., 1921, Windrow Formation-An upland gravel formation of the driftless and adjacent areas of the upper Mississippi Valley: Geological Society of 

America Bulletin 32, p. 293-314. 

Thwaites, R. G., ed., 1904, Original journals of Lewis & Clark 

1804-1806; in 7 vols.: New York. Dodd, Mead & Co. 

Todd, J. E., 1894, A preliminary report on the geology of South 

Dakota: South Dakota Geological Survey Bulletin 1, 172 p. 

__ 1903, Description of the Mitchell quadrangle, South Dakota: 

U.S. Geological Survey Geologic Atlas, folio 99. 

__ 1904, Benton Formation in eastern South Dakota: Geological 

Society of America Bulletin, v. 15, p. 569-575. 

___ 1908, Description of the Elk Point quadrangle, South 

Dakota-Nebraska-Iowa: U.S. Geological Survey Geologic Atlas, 

folio 156. 

Trexler, D. W., 1966, The stratigraphy and structure of the Coalville 

area, northeastern Utah: Professional Contributions of the 

Colorado School of Mines, Number two, 69 p. 

Upham, Warren, 1888, The geology of Crow Wing and Morrison Counties, in The geological and natural history survey of Minnesota: 

The geology of Minnesota, v. 2, p. 580-611. 

Weimer, R. J., 1978, Influence of Transcontinental arch on Cretaceous 

marine sedimentation-a preliminary report, in Energy resources 

of the Denver Basin: Rocky Mountain Association of Geologists 

1978 Symposium, p. 211-222. 

White, C. A.,J870, Report on the geological survey of the State oflowa, 

volume 1: Des Moines, 391 p. 

__ 1893, in H. V. Winchell, Note on Cretaceous in northern Minnesota: American Geologist, v. 12, p. 220-223. 

Williams, G. D., and Stelck, C. R., 1975, Speculations on the 

Cretaceous paleogeography of North America, in W. G. E. 

Caldwell, ed., The Cretaceous System in the Western Interior of 

North America: The Geological Association of Canada Special 

Paper 13, p. 1-20. 

Winchell, H. V., 1893, Note on Cretaceous in northern Minnesota: The 

American Geologist, v. 12, no. 4, p. 220-223. 

Winchell, N. H., 1874, The geological and natural history survey of 

Minnesota; the second annual report for the year 1873, in University of Minnesota Annual Report for 1873: p. 73-219. 

__ 1878, The Cretaceous in Minnesota: Minnesota Academy of 

Natural Sciences, Bulletin 1877, p. 347-350. 

Winter, T. C., Bidwell, L. E., and Maclay, R. W., 1969, Water 

resources of the Otter Tail River watershed, west-central Minnesota: U.S. Geological Survey Hydrologic Investigations Atlas 

HA-296. 

Woodward, Anthony, and Thomas, B. W., 1885, On the Foraminifera 

of the boulder-clay taken from a well-shaft 22 feet deep, Meeker 

County, central Minnesota: Minnesota Geological Survey 

thirteenth annual report, p. 164-177. . 

__ 1895, The microscopical fauna of the Cretaceous in Minnesota, 

with additions from Nebraska and Illinois, in The geological and 

natural history survey of Minnesota: The geology of Minnesota, 

v. 3, pt. 1, p. 23-52. 

Wosick, F. D., 1977, Stratigraphy and paleontology of the Upper 

Cretaceous Morden Member (Vermillion River Formation) in the 

outcrop area, northeastern North Dakota: North Dakota University Master's thesis, 152 p. 

{::{ U.S. GOVERNMENT PRINTING OF:'FICE: 1983-676-041/29 REGION No.8