GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148
Early Jurassic Ammonites from Alaska

By RALPH W. IMLAY

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148

Studies of Early Jurassic ammonites from Alaska 

provide close correlations with Lower Jurassic 

ammonite zones in Europe and with ammonite 

successions elsewhere in the world

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1981
UNITED STATES DEPARTMENT OF THE INTERIOR 

JAMES G. WATT, Secretary

GEOLOGICAL SURVEY

Doyle G. Frederick, Acting Director

Library of Congress Cataloging in Publication Data

Imlay, Ralph Willard, 1908-

Early Jurassic ammonites from Alaska.

(Geological Survey professional paper ; 1148) 

Bibliography: p. 

Supt. of Docs, no.: I 19.16:1148 

Includes index.

1. Ammonoidea. 2. Paleontology Jurassic. 3. Paleontology Alaska. I. Title. II. Series. 

QE807.A51585 564'.53 81-607901

AACR2

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

Washington, D.C. 20402
CONTENTS

Page

Abstract _____________________________________________——— 1

Introduction ______________________________________________ 2

Biologic analysis ___________________________________________ 2

Biostratigraphic summary _____________________________________ 4

Northern Alaska _________________________________________ 4

East-central Alaska ________________________________________ 6

Southern Alaska _________________________________——————— 7

Wrangell Mountains _____________________________________ 7

Talkeetna Mountains ____________________________________ 7

Chulitna River area _____________________________________ 10

Shellabarger and Rainy Pass areas ____________________———————— 10

Kenai Peninsula near Seldovia _______________________________ 10

Puale Bay-Alinchak Bay area _______________________________ 11

Ages and correlations ________________________________________ 11

Hettangian ammonites _____________________________________ 11

Sinemurian ammonites _____________________________________ 12

Pliensbachian ammonites ____________________________________ 17

Toarcian ammonites _______________________________________ 18

Ammonite fauna! setting _______________________________________ 18

Geographic distribution ________________________________________ 18

Systematic descriptions ________________________________________ 28

References cited _________________________________________ 43

Index _________________________________________________ 47

ILLUSTRATIONS

[Plates 1-12 follow index]

PLATE 1. Psiloceras, P. (Franziceras), and Discamphiceras.

2. Waehneroceras, Schlotheimia, and Badouxia.

3. Charmasseiceras, Paltechioceras, and Laqueoceras.

4. Coroniceras, C. (Paracoroniceras), Arietites, and Paltechioceras.

5. Arctoasteroceras, Arnioceras, and Crucilobiceras.

6. Paracaloceras.

7. Crucilobiceras and Fanninoceras.

8. Tropidoceras, Crucilobiceras, Uptonial, and Apoderoceras.

9. Uptonia.

10. Arieticeras, Prodactylioceras, Arieticeras, and Amaltheus.

11. Pseudolioceras, Dactylioceras, D. (Orthodactylites), Grammoceras, Eleganticeras, Harpoceras, Leptaleoceras, Protbgrammoceras, and Fontanelliceras.

12. Haugia, Catacoelocerasl', Brodieia, Protogrammoceras, Pseudolioceras, and Phymatocerasl'.

FIGURE 1. Generalized index map of Lower Jurassic ammonite localities in Alaska __________________________—_——_ 

2-6. Detailed index maps of:

2. Lower Jurassic ammonite localities in the Wrangell Mountains, southern Alaska __________________————

3. Lower Jurassic ammonite localities in the Nelchina area of the Talkeetna Mountains and in the upper part of the 

Matanuska Valley, southern Alaska _______________________________________________

4. Lower Jurassic ammonite localities in the Healy (A-6) quadrangle, Chulitna River area, southern Alaska ____—___

5. Lower Jurassic ammonite localities in the Seldovia area on the Kenai Peninsula, southern Alaska ____________

6. Lower Jurassic ammonite localities in the Puale Bay-Alinchak Bay area, Alaska Peninsula ________________
IV CONTENTS

FIGURE 7. Diagram of European ranges of Early Jurassic ammonite genera present in Alaska ________________________ 9

8. Diagram correlating Early Jurassic ammonite faunas in northern and east-central Alaska _____________________ 10

9. Diagram correlating Early Jurassic ammonite faunas in southern Alaska ______________________________ 11 

10-12. Diagrams showing occurrences and ages of:

10. Ammonites present in the Lower Jurassic beds exposed in the Wrangell Mountains in southern Alaska ________ 12

11. Early Jurassic ammonites present in the Nelchina area of the Talkeetna Mountains and in the upper part of the

Matanuska River Valley, southern Alaska __________________________________________ 13

12. Ammonites present in unnamed Lower Jurassic beds on northeast side of Puale Bay on the Alaska Peninsula ____ 14

13. Diagram correlating Lower Jurassic rocks in northern and east-central Alaska ___________________________ 15

14. Diagram correlating Lower Jurassic rocks in southern Alaska ____________________________________ 16

TABLES

Page

TABLE 1. Ammonite genera and subgenera of Early Jurassic age in Alaska _________________________________—— 2 

2. Early Jurassic ammonites from well cores in northern Alaska _____________________________________ 17 

3-6. Geographic distribution of:

3. Early Jurassic ammonites from outcrops in northern and east-central Alaska _____________________—— 19

4. Early Jurassic ammonites in the Yakutat area and in the Wrangell Mountains in southern Alaska ____________ 20

5. Early Jurassic ammonites in the Talkeetna Mountains in southern Alaska __________________________ 21

6. Early Jurassic ammonites in the Chulitna River area of the Alaska Range, in the Seldovia area of the Kenai Peninsula, and in the Puale Bay-Alinchak Bay and Wide Bay areas of the Alaska Peninsula __________________ 22 

7. Descriptions of Lower Jurassic ammonite localities in Alaska _____________________________________ 24
EARLY JURASSIC AMMONITES FROM ALASKA

By RALPH W. IMLAY

ABSTRACT

Early Jurassic ammonites of early Hettangian to late Toarcian Age 

are present in the lower part of the Kingak Shale and equivalent beds 

in northern Alaska. Well cores from the Arctic Coastal Plain contain 

ammonites of early Hettangian to Sinemurian Age and of late 

Pliensbachian to early Toarcian Age. Surface exposures have furnished ammonites of early Pliensbachian to late Toarcian Age. In addition 

the presence of the pelecypod Otapiria tailleuri Imlay near the base of 

the Lower Jurassic exposures throughout much of northern Alaska is 

good evidence of a Sinemurian Age because this pelecypod occurs in 

the subsurface with ammonites of early Sinemurian Age and it occurs 

on the surface near, but not on the same slabs as, Uptonia of earliest 

Pliensbachian Age.

Ammonites of early Hettangian and late Pliensbachian Age are present in part of the Glenn Shale exposed near Old Rampart in eastcentral Alaska.

In the Wrangell Mountains (lat 62° N., long 141°-143° W.), the upper member of the McCarthy Formation has furnished ammonites of 

early Hettangian to early Sinemurian Age and of latest Sinemurian to 

fairly early Pliensbachian Ages. The overlying Lubbe Creek Formation contains ammonites of middle to late Pliensbachian Age and 

possibly also of early Toarcian Age.

In the Talkeetna Mountains, northeast of Anchorage, the exposed 

upper part of the Talkeetna Formation has furnished ammonites of 

latest Sinemurian to earliest Pliensbachian Age and of late 

Pliensbachian to late Toarcian Age.

In the Chulitna River area, only ammonites of early and latest 

Sinemurian Age have been found. In the Seldovia area, only ammonites of earliest Hettangian and early Sinemurian Age have been 

found. In the Puale Bay area, the Hettangian and lower Sinemurian 

are well represented by ammonites in an unnamed formation. Sharply 

above lies the Kialagvik Formation, which is mostly of Bajocian Age, 

but which contains the ammonite Haugia of middle to early late Toarcian Age about 30 ft (9 m) above its base.

These data show that parts of all these Lower Jurassic sequences are 

not represented by ammonites or are poorly represented. Thus ammonites of late Hettangian and middle Pliensbachian Age are 

represented only by single occurrences, and the Sinemurian zones of 

Caenisites turneri to Oxynoticeras oxynotum are not represented by 

any ammonite occurrences.

The Hettangian ammonite succession in Alaska is similar to that in 

western Europe and probably includes species in common. Its lower 

part, equivalent to the Psiloceras planorbis zone, is represented in 

many areas by P. cf. P. planorbis (J. de C. Sowerby), or by P. (Franziceras) cf. P. (F.) ruidum (Buckman), or by both. Its middle part, probably equivalent to the Alsatites Hosier zone, is represented in the 

Wrangell Mountains by Discamphiceras cf. D. toxophorum (Gumbel), 

at Wide Bay (lat 57°45' N., long 156° W.) by Waehneroceras cf. W. 

portlocki (Wright), and at the Puale Bay-Alinchak Bay area by these 

taxa plus W. cf. W. tenerum (Neumayr) and Laqueoceras cf. L. sublaqueus (Waehner). The upper Hettangian is represented by a single 

specimen of Schlotheimia in the Puale Bay area.

The Sinemurian ammonite succession in Alaska is likewise similar to 

that in western Europe but does not include genera that are definitive 

for nearly half of the stage (Caenisites turneri-Oxynoticeras oxynotum 

j zones). Its lowest part, equivalent to the Arietites bucklandi zone of 

! Europe, is represented in the subsurface of the Arctic Coastal Plain by 

Arietites cf. A. bucklandi (Sowerby), by Charmasseiceras, and by 

species of Coroniceras both below and above Charmasseiceras. Its 

lowest part in southern Alaska is represented in the Chulitna River, 

Seldovia, and Puale Bay areas by Paracaloceras rursicostatum 

Frebold, which in the Chulitna area is associated with Badouxia 

canadensis (Frebold).

The overlying beds in most of these areas are characterized by Arnioceras, whose presence and stratigraphic position are evidence for 

correlation with the late early Sinemurian Arnioceras semicostatum 

zone of Europe. Such an age for Arnioceras in the Arctic Coastal Plain 

is confirmed by its position below that of Coroniceras, a genus not 

known above the A. semicostatum zone. Such an age for Coroniceras 

(Paracoroniceras) in the Seldovia area is shown by the known range of 

the subgenus in Europe.

The highest part of the Sinemurian, representing the Echioceras 

raricostatum zone, has been identified by the occurrence of 

Paltechioceras in the Wrangell and Talkeetna Mountains and in the 

Chulitna River area. That genus in the Talkeetna Mountains is 

associated with Crucilobiceras, which ranges upward into the lower 

Pliensbachian. In the Chulitna River area Paltechioceras is associated 

with Arctoasteroceras, a genus that in arctic Canada occurs with Oxynoticeras oxynotum (Quenstedt).

The Pliensbachian ammonite succession in northern Alaska is incomplete. At its base, the Uptonia jamesoni zone is represented by Uptonia cf. U. jamesoni (J. de C. Sowerby) obtained from outcrops near 

the Ipnavik and Etivluk Rivers (tributaries of the Colville River). The 

next two higher zones of western Europe have not been recognized. 

The still higher zone ofAmaltheus margaritatus is present throughout 

northern Alaska as well as farther southeast in the Old Rampart area 

of east-central Alaska. The highest zone of Pleuroceras spinatum is 

represented by Amaltheus (Pseudoamaltheus) engelhardti in the subsurface of the Arctic Coastal Plain. These occurrences of Amaltheus in 

abundance at many places furnish exact correlations with the upper 

Pliensbachian beds of northern Eurasia.

Pliensbachian ammonite successions in southern Alaska have been 

identified only in the Wrangell and Talkeetna Mountains and questionably in the Yakutat district. The Uptonia jamesoni zone is 

represented in the Wrangell Mountains by Uptonia cf. U. 

dayiceratoides Mouterde, in the Talkeetna Mountains by 

Apoderoceras, and probably in the Yakutat district by a fragment that 

resembles the outer whorl of Uptonia rather than Crucilobiceras. The 

next higher zone of Tragophylloceras ibex, is represented by 

Tropidoceras actaeon (d'Orbigny) in association with Crucilobiceras. 

The Prodactylioceras davoei zone is possibly represented in the 

Wrangell Mountains by some float specimens of Prodactylioceras that 

were collected along with Uptonia. The highest two zones of the 

Pliensbachian are represented by the ammonites Protogrammoceras, 

Leptaleoceras, Arieticeras, and Fontannelliceras, which are identical
EARLY JURASSIC AMMONITES FROM ALASKA

or nearly identical with species in the Mediterranean area. With these 

taxa at one locality in the Talkeetna Mountains were found two 

specimens ofAmaltheus.

This association with Amaltheus furnishes a correlation with the upper Pliensbachian of northern Alaska. Otherwise the late 

Pliensbachian ammonites in southern Alaska have nothing in common 

generically with ammonites of that age in the Arctic region. The same 

genera do occur farther south, however, in western British Columbia 

and in eastern Oregon, as well as in the Mediterranean area.

The Toarcian ammonite succession in Alaska is similar to that in 

western Europe and probably includes species in common. 

Characteristic taxa from the base upward include (1) Dactylioceras 

and Catacoeloceras (?), (2) Harpoceras cf. H. exaratum (Young and 

Bird) and Eleganticeras, (3) Haugia, Brodieia, and Pseudolioceras, 

and (4) Pseudolioceras and Grammoceras. The most complete Toarcian 

ammonite sequence is in the Talkeetna Mountains.

INTRODUCTION

Early Jurassic ammonites obtained from eight areas 

in northern, eastern, and southern Alaska (figs. 1-6) are 

described herein in order to present all available 

evidence concerning the stratigraphic and geographic 

distribution of the taxa (figs. 7-9), to evaluate their 

faunal setting in relation to other parts of the world, to 

make regional and continental correlations, and to date 

the formations in Alaska as precisely as possible in 

terms of the standard Jurassic zones of western Europe 

(figs. 10-14).

This study is based mainly on fossil collections and 

stratigraphic data furnished by many U.S. Geological 

Survey geologists, as listed in Imlay and Detterman 

(1973, p. 8, 9). It is also based on excellent fossil collections and data obtained by British Petroleum (Alaska), 

Inc., in 1964 in northern Alaska and by the Richfield Oil 

Co. (now Atlantic Richfield Oil Co.) in 1962 on the east 

shore of Puale Bay in the Alaska Peninsula. 

Biostratigraphic data for northern Alaska were furnished by W. P. Brosge, R. L. Detterman, and H. N. 

Reiser; for east-central Alaska, by E. M. MacKevett, 

Jr.,; for the Talkeetna Mountains, by Arthur Grantz; 

and for the Chulitna Valley, by D. L. Jones.

The described specimens are deposited in the type collections of the U.S. National Museum and are labeled 

USNM.

BIOLOGIC ANALYSIS

Alaska ammonites of Early Jurassic (Hettangian to 

Toarcian) age described or mentioned herein number 

about 500 specimens whose distribution by family, subfamily, genus, and subgenus is shown on table I. This 

table shows that the families present include the 

Arietitidae (15 percent), Polymorphitidae (20 percent), 

Schlotheimiidae (16 percent), Hildoceratidae (15 percent), Psiloceratidae (9 percent), Hammoceratidae (6 

percent), and Eoderoceratidae (6 percent). The remaining families combined represent only 13 percent of the 

total number of specimens.

The classification shown in table 1 is essentially that 

proposed by Donovan and Forsey (1973 p. 2-4), except 

for Fanninoceras and Arctoasteroceras, which those 

writers consider to be synonyms of Radstockiceras and 

Aegasteroceras, respectively. Nonetheless, Fanninoceras (McLearn, 1930, p. 4, 5; 1932, p. 76-80) differs 

morphologically from Radstockiceras by having a thinner whorl section and an undercut umbilical wall 

(Frebold, 1967a, p. 1146). It differs timewise by occurring in beds of late Pliensbachian Age in eastern Oregon 

(Imlay, 1968, p. CIO, Cll) and in beds of earliest to 

latest Pliensbachian Age in the Queen Charlotte Islands 

(Hans Frebold, written commun., 1975), whereas 

Radstockiceras in northwest Europe is characteristic of

TABLE I. Ammonite genera and subgenera of Early Jurassic age in

Alaska

Family Subfamily Genus and subgenus Number of 

specimens

Lytoceratidae. 

Psiloceratidae

Schlotheimiidae.

Arietitidae ____ Arietitinae.

Xipher oceratinae. 

Coeloceratinae_

Lytoceras ________ 1

Psiloceras________ 10

(Franziceras) ___ 14

Discamphiceras__ 19

Laqueoceras____ 1

Schlotheimia _____ 4

Waehneroceras ___ 63

Badouxia ________ 4

Charmasseiceras_ 8

Arietites_________ 1

Coroniceras ______ 17

(Paracoroniceras) 3

Arnioceras_______ 45

Arniocerasl ______ 1

Paracaloceras ____ 10

Asteroceratinae__Arctoasteroceras _ 2

___________Paltechioceras ____ 10

(Orthechioceras) _ 1

._Crucilobiceras ____ 26

-Apoderoceras_____ 2

Apoderocerast ____ 1

_ Fanninoceras_____ 16

_ Uptonia _________ 81

Uptonia!______ 9

Tropidoceras _____ 4

_ A maltheus _______ 18

(Pseudoamaltheus)____ 1

_ Prodactylioceras _ 4

Dactylioceras_____ 6

(Orthodactylites)_ 1

Catacoelocerasl __ 1

Hildoceratidae__ Arieticeratinae__Arieticeras_______ 42

Leptaleoceras_____ 1

Fontanelliceras ___ 5

Harpoceratinae __ Harpoceras ______ 5

Protogrammoceras 5

Elegantuliceras __ 12

Pseudolioceras____ 5

_ Grammoceras?__ 1

-Phymatocerasl____ 3

Brodieia_________ 1.

Haugia__________ 28

E chiocer atidae _ 

Eoderoceratidae _

Oxynoticer atidae. 

Polymorphitidae _

Amaltheidae.

Dactylioceratidae_

Hammatoceratidae

Grammoceratinae. 

Phymatoceratinae.
BIOLOGIC ANALYSES

FIGURE 1.—Generalized index map of Lower Jurassic ammonite areas in Alaska, as listed in tables 3-7.

the earliest Pliensbachian (Dean and others, 1961, p. 

463, fig. 7).

The genus Arctoasteroceras of Frebold (1960, p. 13, 

14, pi. 2 figs. 1-5, pi. 3, figs. 1-3) differs morphologically 

from Aegasteroceras of Spath (1925, p. 265, 267, fig. 6a) 

by having weak ribs on the upper parts of the flanks and 

on the venter and commonly by having an asymmetrical 

suture line. These differences were not accepted as valid 

by Hallam (1965, p. 1495) or by Donovan and Forsey 

(1973, p. 3). Nonetheless, some European specimens of 

Aegasteroceras, including the holotype of the genotype 

species, A. simile Spath (Guerin-Franiatte, 1966, p. 

310-313, pis. 189-192), bear strong ribs on the upper

part of the flanks and on the margins of the venter, and 

some ribs are weakly connected across the venter. This 

strong ribbing contrasts markedly with the weak ribs on 

Arctoasteroceras jeletzkyi Frebold from Canada.

These genera likewise differ slightly in age. Thus, 

Aegasteroceras in Europe occurs in the zone of 

Asteroceras obtuswn of earliest late Sinemurian Age 

(Dain and others, 1961, p. 454). Arctoasteroceras jeletzkyi in Canada is dated as middle late Sinemurian 

because of its occurrence with Oxynoticeras oxynotwn 

and below echioceratid ammonites (Frebold, 1960, p. 14, 

26). The Alaskan specimens of Arctoasteroceras described herein are dated as probably latest Sinemurian
143°30'

EARLY JURASSIC AMMONITES FROM ALASKA

143°00' 142°30'

61°30' --

28540 N 

X X 28535 

8690 . x X —•j C1 / 

lamona 723537

& 

28538

FIGURE 2.—Detailed index map of Lower Jurassic ammonite localities in the Wrangell Mountains, southern Alaska.

because they were collected with Paltechioceras (Orthechioceras1!), which in Europe occurs only in the 

Echioceras raricostatum zone (Getty, 1973, p. 6).

The characteristics of the Early Jurassic ammonites 

described herein agree very well with those of various 

genera and subgenera defined in the "Treatise on Invertebrate Paleontology" (Arkell and others, 1957). In 

addition, the taxonomy of the Psiloceratidae has been 

discussed by Donovan (1952, p. 634, 641) and Frebold 

(1967b, p. 17); the Schlotheimiidae by Lange (1951, p. 

23, 25), Donovan (1952, p. 644-655), Frebold (I960, p. 

13), and Guex and Taylor (1976, p. 525); the Arietitidae 

by Donovan (1952, p. 717, 725, 739, 746), Donovan and 

Forsey (1973, p. 6, 7), and Guerin-Franiatte (1966, p. 

106-118, 150, 252, 281, 283, 309, 310, 313); the 

Echioceratidae by Getty (1973, p. 7, 8, 17-21, 23, 24); 

the Amaltheidae by Howarth (1958, pt. 1, p. 1, 21; pt. 2); 

the Polymorphitidae by Bremer (1965, p. 177); the Dactylioceratidae by Pinna and Levi-Setti (1971) and

Schmidt-Effing (1972); the Polymorphitidae, Dactylioceratidae, and Hildoceratidae by Geczy (1976); and 

the Dactylioceratidae by Fischer (1966, p. 20-48). In addition, the taxonomy of the Early Jurassic ammonite 

families of southern Germany has been briefly described 

by Schlegelmilch (1976, p. 32-95).

BIOSTRATIGRAPHIC SUMMARY

NORTHERN ALASKA

Lower Jurassic marine beds cropping out in northern 

Alaska (figs. 1, 13) have been briefly described or mentioned by Imlay and Detterman (1973, p. 9; p. 12 fig. 

11B). Those from the Sagavanirktok River eastward 

have been described in considerable detail by Detterman 

and others (1975, p. 18-20). In general the outcrops are 

poorly exposed and sparsely fossiliferous, but they have 

furnished fossils representing most of the Pliensbachian 

and Toarcian Stages and perhaps the Sinemurian (fig. 

8). Field studies to 1978 are insufficient to demonstrate
BIOSTRATIGRAPHIC SUMMARY

148°00' 147°30'

62°00'

FIGURE 3.—Detailed index map of Lower Jurassic ammonite localities in the Nelchina area of the Talkeetna Mountains and in the upper part of

the Matanuska Valley, southern Alaska.

whether the absence of earlier Jurassic is due to lack of 

deposition, poor outcrops, or insufficient field work in 

poorly fossiliferous beds.

The westernmost exposures in the DeLong Mountains 

consist mostly of clay shales that bear limestone concretions, are of unknown thickness, and have furnished ammonites of late Pliensbachian to early Toarcian Age. 

Next to the east between the Ipnavik and Itkillik Rivers, 

the Lower Jurassic apparently consists of 60 feet (18 m) 

or less of siliceous claystone that locally contains some 

limestone and is dated as Sinemurian to early 

Pliensbachian. Such an age is shown by the widespead 

distribution of Otapiria tailleuri Imlay, which in the 

subsurface is found associated only with ammonites of 

early Sinemurian Age, and by the presence on the surface of the early Pliensbachian ammonite Uptonia in 

slabs that do not contain Otapiria, although that genus 

occurs nearby.

Still farther east, in the area between the

Sagavanirktok and Aichilik Rivers, the Lower Jurassic 

beds (Detterman and others, 1975, p. 18-20, 44) represent the lower part of the Kingak Shale and range in 

thickness from 100 feet (30 m) or less, to about 900 feet 

274 m. This lower part consists of fissile black papery 

shale that at the Aichilik River is about 600 feet (180 m) 

thick and on the Kavik River contains Otapiria tailleuri 

Imlay of Sinemurian Age. The upper part consists of 

dark-gray clay shale and claystone that in places is as 

much as 300 feet (92 m) thick and contains ammonites of 

late Pliensbachian to late Toarcian Age.

The Lower Jurassic sequences in the subsurface of 

northern Alaska differ from those on the surface mainly 

by containing minor amounts of glauconitic sandstone, 

by being somewhat more fossiliferous, and by containing ammonites representing all Lower Jurassic stages 

(table 2). They have not, however, furnished any ammonites representing middle Sinemurian to middle 

Pliensbachian time, or late Toarcian time.
EARLY JURASSIC AMMONITES FROM ALASKA

50' 40' 149°30'

63°00'

FIGURE 4.-Detailed index map of Lower Jurassic ammonite localities in the Healy (A-6) quadrangle, Chulitna River area, southern Alaska.

EAST-CENTRAL ALASKA

In the northern part of east-central Alaska, the Lower 

Jurassic is poorly exposed but is reported to consist of 

about 1000 feet (305 m) of sandstone, siltstone, shale, 

and quartzite that are part of the Glenn Shale (Brosge

and Reiser 1964, 1969; Imlay and Detterman, 1973, p. 

13, 14). The basal 120 feet (37 m) exposed on Spike 

Mountain about 30 miles (48 km) north of Old Rampart, 

consists of sandy beds, rests on granite, and contains 

the Hettangian ammonites Psiloceras (Psiloceras) and
BIOSTRATIGRAPHIC SUMMARY

R. 15 W. R. 14 W.

FIGURE 5.—Detailed index map of Lower Jurassic ammonite localities in the Seldovia area (Seldovia (B-5) quadrangle) on the Kenai Peninsula,

southern Alaska.

P. (Franziceras) throughout. The only other Jurassic 

ammonite from the same general area is a specimen of 

Amaltheus stokesi (J. Sowerby) obtained about 9 miles 

(14.4 km) east-southeast of Old Rampart.

SOUTHERN ALASKA

WRANGELL MOUNTAINS

The Lower Jurassic sequence in the Wrangell Mountains has been described in detail by MacKevett (1969, 

1970, 1971); has been mentioned briefly by Imlay and 

Detterman (1973, p. 8,11) regarding its position relative 

to a Jurassic volcanic island-arc system; and is depicted 

herein (figs. 10, 14) in regard to fossil occurrences and 

ages. Most of the sequence is represented by the upper 

member of the McCarthy Formation which consists of

2,000-2,500 feet (610-760 m) of very thin to mediumbedded, dark-gray laminated chert and spiculite, grades 

into adjoining lithologic units, and is of Hettangian, 

Sinemurian, and earliest Pliensbachian Age. At the top, 

of the sequence is the Lubbe Creek Formation, which 

consists of 100-300 feet (30-91 m) of medium-gray 

spiculite and chert, is overlain unconformably by beds of 

Bajocian Age, and is of middle and late Pliensbachian to 

possibly early Toarcian Age.

TALKEETNA MOUNTAINS

The Lower Jurassic sequences in the Nelchina area of 

the Talkeetna Mountains and in the adjoining upper part 

of the Matanuska River valley (figs. 11, 14) have been 

studied by Arthur Grantz. Most of the lithologic and
EARLY JURASSIC AMMONITES FROM ALASKA

57°45' 155°25' 155°20'

SHELIKOF FORMATION

KIALAGVIK FORMATION

VABM 119 Bay /

ROC1303

X 

21237 P< ROC1282 and 1283

12075, 12394, 

25694, 29268, 

and ROC3002

UNNAMED LOWER JURASSIC BEDS

10820 (part), 12396 (part), 31372 

x ROC 1240 and ROC1241

3110, 12396 (part), 19803, 25694, 

> 29267, M1738 and ROC1185

UNNAMED TRIASSIC BEDS

FIGURE 6.—Detailed index map of Lower Jurassic ammonite localities in the Puale Bay-Alinchak Bay area, Alaska Peninsula.

stratigraphic data shown in figure 11 were prepared by 

Grantz (written commun., 1977), along with these comments:

The Talkeetna Formation comprises a diverse assemblage of 

volcanic arc deposits. Waterlain pyroclastic and tuffaceous sedimentary rocks are much dominant over lava flows. If all rocks mapped as 

Talkeetna Formation are correctly assigned, its composition ranges 

from basaltic to rhyolitic, with andesitic rocks apparently dominant. 

The Talkeetna volcanic breccias and tuffs were commonly, and perhaps 

dominantly, deposited in marine waters. Marine fossils are 

widespread, and locally abundant in the water-laid tuffs and in 

associated more-or-less tuffaceous sands and lutites. However, the 

presence of thick intervals of coarse volcanic breccias, tuffs and some 

flows that are barren of fossils and some outcrops that are rich in plant 

fossils suggest that nonmarirte facies may also constitute an important 

part of the formation. Presumably, the fossiliferous marine beds represent inter-volcanic vent or arc-distal facies, and the pyroclastic and 

plant-rich beds represent submarine and subaerial composite volcanic 

cones that formed at major volcanic vents.

The Talkeetna Formation in the upper Matanuska Valley and 

Nelchina area occurs in large but well-separated outcrop areas. The 

lack of mapping continuity combined with moderate to locally great 

structural complexity, locally intense plutonism, and some metamorphism makes the recognition of the stratigraphic succession in these 

rocks difficult. The chief problem is the possibility, indeed probability, 

that the local lithologic succession in each isolated outcrop area of the 

formation owes as much, or more, to its geographic position (i.e., 

facies) as to its biostratigraphic position. However, if the prior assumption is made that the local succesions do have regional validity, then [a] 

* * * gross, and incomplete, succession can be inferred. Even with this 

assumption, however, the reconstruction given does not represent the 

only possible explanation of the available facts.

On the basis of these data and inferences, the Talkeetna Formation of the Talkeetna Mountains is 

15,000-19,000 feet (4,660-5,790 m) thick, is incompletely exposed basally, is dominated by volcanic rocks, is 

mostly marine, and contains ammonites of latest
BIOSTRATIGRAPHIC SUMMARY

(Franziceras) — — —

Laqueoceras — — — —

Waehneroceras — — —

Coroniceras — — — — 

(Paracoroniceras) —

Paracaloceras — — —

Aegasteroceras

(Orthechioceras) — —

Apoderoceras — — — —

Tropidoceras — — — —

Leptaleoceras — — —

Elegantuliceras — — —

Phymatoceras — — —

Hettangian

Psilocaras planorbis

Alsatites liasicus

Schlotheimia angulta

Sinemurian

Lower

Arietites buck/and/

—

Arnioceras semicostatum

Caenisites turner/

Upper

Asteroceras obtusum Oxynoticeras oxynotum Echioceras raricostatum

Pliensbachian

Lower

jamesoni Uptonia 

-

Tragophylloceras ibex

— ? 

i

Prodactylioceras davoei

->.

Upper

Amaltheus margaritatus Pleuroceras spinatum

— ?

Toarcian

Lower

Dactylioceras tenuicostatum

falcifer Harpoceras 

——

Hildoceras bifrons

Upper

Haugia variabilis

Grammoceras thouarsense

— •?

Dumortieria levesquei

FIGURE 7.—European ranges of Early Jurassic ammonite genera present in Alaska.
10 EARLY JURASSIC AMMONITES FROM ALASKA

1<D w

0

D

0)

0) 

D) 

2

w

rcian

.2

c

10

!c

10 

-Q

.2 

CL

10

D

0)

c

c

10

D)

c

10

CD

I

Northwest European 

Ammonite zones 

(After Dean, Donovan, 

and Howarth, 1961)

Dumortieria levesquei

Grammoceras thouarsense

Haugia variabilis

Hildoceras bifrons

Dactylioceras tenuicostatum

Pleuroceras spinatum

Prodactylioceras davoei

Tragophylloceras ibex

Uptonia jamesoni

Echioceras raricostatum

Oxynoticeras oxynotum

Asteroceras obtusum

Caenisites turner/

Arnioceras semicostatum

Arietites bucklandi

Schlotheimia angulata

Alsatites liasicus

Psiloceras planorbis

Arctic Coastal Plain 

in subsurface of 

Point BarrowCape Simpson area

Dactylioceras

(Orthodactylites) 

and Catacoeloceras (?)

Amaltheus engelhardti

A. margaritatus

A. stokesi

Arnioceras and 

Coroniceras

Arietites, Coroniceras, 

and Charmasseiceras

Waehneroceras ?

Psiloceras 

(Franziceras)

DeLong Mountains 

area near 

Thetis Creek and 

Epewik River 

northwestern Alaska

Harpoceras cf. H.

Eleganticeras

Dactylioceras

(Orthodactylites) 

cf . D. (O. ) directum

Amaltheus

margaritatus

Ipnavik-Anaktuvuk 

Rivers area 

north-central Alaska

Uptonia cf. 

U. jamesoni

Ignek Valley in 

Mt. Michelson (C-4) 

quadrangle to 

Aichilik River in 

northeastern Alaska

Psuedolioceras

Harpoceras cf. H,

exaratum

/ Amaltheus \

stokesi

Old Rampart 

area in 

east-central 

Alaska

/ Amaltheus \

stokesi

Psiloceras 

(Franziceras)

FIGURE 8.—Correlation of Early Jurassic ammonite faunas in northern and east-central Alaska.

Sinemurian to late Toarcian Age (fig. 11). Other studies 

show (Grantz and others, 1963) that the Talkeetna Formation is overlain unconformably by beds of early Bajocian Age, that the unconformity is dated paleontologically as of latest Toarcian and earliest Bajocian 

Age, and that the formation is intruded by granitic rocks 

that may be of the same age as the unconformity.

CHULITNA RIVER AREA

The Lower Jurassic sequence exposed in the Healy 

(A-6) quadrangle in the south-central part of the Alaska 

Range has not been described. It has furnished ammonites of early Sinemurian Age at six localities and of 

latest Sinemurian Age at one locality (fig. 4). Most of the 

ammonites of early Sinemurian Age are preserved in a 

matrix of gray calcareous sandstone or of silty 

phosphatic limestone. The ammonites of latest 

Sinemurian Age (USGS Mesozoic loc. 31261) are 

preserved in a unit of massive tuffaceous argillite that 

apparently underlies, or is in fault contact with, siliceous 

argillite of Late Jurassic age (Jones and others, 1980).

SHELLABARGER AND RAINY PASS AREAS

The Lower Jurassic sequences exposed in the Talkeetna (C-6) and (B-6) quadrangles in the south-central part 

of the Alaska Range have not been described. In the 

Rainy Pass area of the Talkeetna (B-6) quadrangle, Early Jurassic fossils were obtained from gray, calcareous, 

fine-grained sandstone. In the Shellabarger Pass area of 

the Talkeetna (C-6) quadrangle, such fossils were obtained from brown siltstone and sandstone in T.28 N., 

R. 19 W.

KENAI PENINSULA NEAR SELDOVIA

Lower Jurassic beds are exposed on the shore of the 

Kenai Peninsula for several miles southwestward from 

Seldovia Bay (figs. 5, 14) in the northwestern part of the 

Seldovia (B-15) quadrangle. They consist of interbedded 

tuff, agglomerate, sandstone, shale, and limestone that 

probably are 2,000-3,000 feet (610-915 m) thick, according to Martin (1926, p. 135). The same sequence, based 

on unpublished field studies by Don Miller and the 

author for the U.S. Geological Survey in 1948, includes a 

thick middle unit consisting of unfossiliferous red lava,
AGES AND CORRELATIONS 11

a>

a> 

to

Jurassic Lower 

a>

D> 

CO

55

Toarcian

Pliensbachian

inemurian

c 

.5 

5>

c

fi

<D

Northwest European 

Ammonite zones 

(Modified from Dean, Donovan 

and Howarth, 1961)

Dumortieria levesquei

Grammoceras thouersense

Haugia variabilis

Hi/doceras bifrons

Harpoceras falcifer

Dactylioceras tenuicostatum

Pleuroceras spinatum

Amaltheus margaritatus

Prodactylioceras davoei

Tragophy/loceras ibex

Uptonia jamesoni

Echioceras raricostatum

Oxynoticeras oxynotum

Asteroceras obtusum

Caenisites turner/

Arnioceras semicostatum

Arietites buck/and/

Schlotheimia angulata

Alsatites liasicus

Psiloceras planorbis

Wrangell Mountains 

n southern Alaska

•>

Peronoceras ? 

Weyla dufrenoyi 

and W, alata

Arieticeras cf. 

A. domarense 

and 

Prodactylioceras (?)

Pro dactyl ioceras 

italicum

Tropidoceras

i <§ 

Uptonia ^ ^

2 "

C3 

Paltech/oceras

7

Arnioceras

Coroniceras? and 

arietitid ammonites

Discamphiceras

Psiloceras cf. P. 

planorbis

Talkeetna Mountains 

in southern Alaska

Grammoceras

Pseudolioceres , 

Haugia, Brodieia 

and Phvmatoceras (?)

Harpoceras cf. H. 

exaratum

Dactylioceras cf. D. 

commune and 

D. (Orthodactylites) 

kanense

Protogrammoceras, 

Amaltheus, Arieticeras, 

Fontanelliceras 

and Leptaleoceras

Uptonia'?

Apoderoceras

Pa/tech ioceras and 

Crucilobiceras

Chulitna River area 

in Healy (A-6) quad, 

south-central part 

of Alaska Range

Pa/tech ioceras and 

Arctoasteroceras

Arnioceras

/ Paracaloceras \ 

and Badouxia

Seldovia area on 

the Kenai Peninsula

->

Coroniceras 

(Paracoroniceras )

/ Paracaloceras \ 

rursicostatum

Psiloceras 

(Franziceras)

Puale Bay area on 

the Alaska Peninsula

Haugia and 

Pseudol ioceras

->

Arnioceras

/ Paracaloceras \ 

rursicostatum

Schlotheimia

/ Waehneroceras , \ 

/ Discamphiceras, ^ 

and Lagueoceras

Psiloceras cf. P. 

planorbis

FIGURE 9.—Correlation of Early Jurassic ammonite faunas in southern Alaska.

green lava, tuff, and agglomerate overlain and underlain 

by units consisting of green sandstone, tuffaceous sandstone, tuff, agglomerate, and gray limestone. Fossils occur in limestone, tuff, and sandstone beds in both the 

lower and upper units. The ammonites present are of 

Hettangian and early Sinemurian Age.

This Lower Jurassic sequence, on the basis of recent 

studies by Kelley (1978, p. 2356), is about 4,000 m thick 

and consists mainly of pyroclastic breccias and tuff. It is 

divisible into three mappable lithofacies, from bottom to 

top: (1) a "graded pyroclastic lithofacies" deposited 

below wave base; (2) a "pyroclastic debris flow and turbidite lithofacies" deposited below wave base; and (3) a 

"reworked volcaniclastic lithofacies" marked basally by 

fairly thick coal beds but deposited partly under tidal 

influences. Kelley noted that fossils occur in all three 

units.

PUALE BAY-ALINCHAK BAY AREA

The Lower Jurassic sequence in the Puale Bay area, as 

described by Imlay and Detterman 1977), is at least 

1,850 feet (550 m) thick. At its base is a limestone unit 

about 780 feet (238 m) thick that in its lower part contains ammonites of Hettangian Age and that rests conformably on limestone of latest Triassic age. The overlying 1,040 feet (317 m) of beds consists mostly of 

massive tuffaceous conglomeratic sandstone but includes some siltstone and limestone. These beds contain 

ammonites of early Sinemurian Age. This sandstone is 

overlain sharply by sandy siltstone of the Kialagvik Formation, which is mostly of early to middle Bajocian Age. 

Its lowest beds, however, are of middle to early late 

Toarcian Age, as shown by the presence of Haugia 

about 30 feet (9 m) above its base. The Toarcian probably also includes some of the overlying 320-370 feet 

(98-113 m) of siltstone between this occurrence of 

Haugia and the lowest occurrence of Pseudolioceras 

whiteavesi (White) of late early Bajocian Age (figs. 9, 

12). The sharp contact at the base of the Kialagvik Formation probably represents a fault rather than an unconformity.

AGES AND CORRELATIONS

HETTANGIAN AMMONITES

Hettangian ammonites have been found in the subsurface of northern Alaska, in the Old Rampart area of
12 EARLY JURASSIC AMMONITES FROM ALASKA

Lower Jurassic 

formation

Lubbe Creek 

Formation

Upper Member 

of McCarthy 

Formation

Lithologic characteristics 

and thicknesses

100-300 ft (30.5-91.5 m) 

Mostly medium gray, impure

spiculite chert. 'A few beds 

of bioclastic coquina near top

2000-2500 ft (61 0-762 m) 

Very thin-to medium-bedded, 

dark-gray /finely laminated 

organic chert and spiculite. 

Includes small amounts of fissile, 

calcareous to carbonaceous

shale and limestone. Shale

becomes more common in upper

part

Contacts are 

gradational

Fossiliferous areas in 

McCarthy C4-C6 and 

B-4 quadrangles

- 7 C-5 West of West Fork

- 7 C-5 East of McCarthy Creek

- C-5 West of Nizina River 

- C-5 West of McCarthy Creek 

I>C-4 Chitistone Mountain 

_^C-6 Ridge west of Root Glacier 

~^C-6 Ridge west of Root Glacier 

~~-C-5 Ridge between Lubbe Creek 

and Diamond Creek

- ? C-5 East of McCarthy Creek

- C-5 West of West Fork

->, C-5 Ridge between 

__/ McCarthy Creek and

West Fork

xC-5 Ridge west of

McCarthy Creek

- 7 B-4 Chitistone Mountain

- ? B-4 Chitistone Mountain

U.S. Geological 

Survey Mesozoic 

fossil localities

- 7 28678

- 28531

_ 28688 

- 28534 

- 28671-73,28675 

" 31175 

- 31174 

- 728690

- 14030

- 28535

- 28538 

- 28537

- 728533

- 729890

- 729891

Ammonite genera in 

McCarthy C4-C6 

and B-4 

quadrangles

- ? Peronoceras?

- Arieticeras

_ Arieticeras 

— Tropidoceras and Crucilobiceras 

~ Uptonia and Prodacty/ioceras 

Pa/techiocerasf and Crucilobiceras 

~ Pa/techioceras 

~ 7 Crucilobiceras

— Crucilobiceras

- Arnioceras

- Arnioceras 

- Arietitid ammonites

- ? Coroniceras?

- Discamphiceras and Alsatitesl

- ? Psiloceras

Stage

Lower 

Toarcian

Pliensbachian

c

<o

D

E

CD

C

i/3

(D

a

a

D

— 7 —

aj

_i

Hettangian

FIGURE 10.—Occurrences and ages of ammonites present in the Lower Jurassic beds exposed in the Wrangell Mountains, southern Alaska.

northern east-central Alaska, in the Wrangell Mountains of southern Alaska, in the Seldovia area of the 

Kenai Peninsula and in the Puale Bay-Alinchak Bay and 

Wide Bay areas of the Alaska Peninsula (figs. 8-10, 12). 

The earliest Hettangian is represented in all these 

areas, except for Wide Bay, either by a fairly smooth 

species of Psiloceras or by the ribbed subgenus P. (Franziceras) similar to P. (F.) ruidum (Buckman). The middle 

Hettangian, probably correlative with the Alsatites 

liasicus zone of Europe, is characterized by 

Waehneroceras at Wide Bay, by Waehneroceras, 

Discamphiceras, and Laqueoceras at Puale Bay, by 

Discamphiceras in the Wrangell Mountains, and questionably by Waehneroceras in the Arctic Coastal Plain 

near Point Barrow (fig. 8). The late Hettangian, correlative with the Schlotheimia angulata Zone, is 

represented by one specimen of Schlotheimia in the 

Puale Bay area. All these genera are represented by 

species that are closely similar to, and probably in part 

identical with, species described from western Europe. 

Evidently the succession of Hettangian ammonite

genera and species in Alaska is the same as in western 

Europe.

SINEMURIAN AMMONITES

Sinemurian ammonites have been found in northern 

Alaska only in the subsurface of the Point Barrow-Cape 

Simpson area (fig. 7). In southern Alaska, such ammonites occur in five areas from the Wrangell Mountains on the east to Puale Bay on the west (figs. 10-12). 

The lower Sinemurian zones of Arietites bucklandi and 

Arnioceras semicostatum are represented in all these 

areas except in the Talkeetna Mountains, where beds of 

that age are not exposed. The uppermost Sinemurian 

(Echioceras raricostatum Zone) is represented in the 

Wrangell and Talkeetna Mountains and in the Chulitna 

River area of the Alaska Range. The remainder of the 

Sinemurian (Caenisites turneri, Asteroceras obtusum, 

and Oxynoticeras oxynotum Zones) has not been identified by ammonites anywhere in Alaska but is probably 

represented by poorly fossiliferous beds in the Arctic 

Coastal Plain, in the Wrangell Mountains, and possibly 

elsewhere.
AGES AND CORRELATIONS 13

Talkeetna Formation 

in the Nelchina 

area of the 

Talkeetna Mountains

^IXUJ^l^ULXU.

1500 ft (457 m)

Well-bedded marine strata

dominated by siliceous lutite.

tuffaceous sandstone, and

epiclastic 

volcanic sandstone

2300 ft (701 m)

Well-bedded, tuffaceous

marine strata

and thick beds of

tuff and agglomerate

8000 ft (2438 m)

Thick-bedded volcanic breccia, 

tuff and some lava flows 

Base not observed.

'///////////

2500 ft (762 m)

Well-bedded marine 

tuff, tuffaceous sandstone 

and siliceous lutite. 

Base not observed and 

possibly not exposed

'///////////

1000-5000 ft (305-1524 m)

Well-bedded, marine, siliceous.

tuffaceous, lutite and sandstone;

limestone and marl; tuff; and

some lava flows.

Base not observed.

Areas of Lower Jurassic 

outcrops in the 

Nelchina area and in 

the upper part of 

Matanuska River valley

— Copper River Basin

South side of

west part

> Northern Horn Mountains

— Northern Horn Mountains

— Eest end Sheep Mountain

_ South side of upper

Matanuska River valley

Southern Horn Mountains and 

west "part of Sheep Mountain

Northeast end of Sheep 

Mountain

_ /South side of upper 

(JVIatanuska River valley

_ fvalley of Doone Creek 

\on west side of Chickaloon River

— Valley of Doone Creek

— Between headwaters of

Black and Oshetna Rivers

U.S. Geological Survey 

Mesozoic fossil localities

— 25939

^ 24111,25316-25319,25342 

J 25359 and 27508

— 24114,25940

— 24787

— 29198

No fossils 

found

T24107, 24108, 25941, 

\29449 and 29450

— 27586

— 6697 and M6171

— 6706

— 26722, 28661-63

Ammonite genera

— Grammoceras

}

Pseudolioceras, Haugia 

and Phymatoceras (?)

— Haugia and Brodieia

— Dactylioceras

Harpoceras and

Orthodactylites

J

Amaltheus, Fanninoceras,

Protogrammoceras,

Arieticeras, Fontanelliceras 

and Leptaleoceras,

Arieticeras, Fanninoceras and 

Fontanelliceras

[Apoderoceras and 

\ilptonial

— Crucilobiceras

— Paltechioceras and

Crucilobiceras

Stage

c 

'o

<O

J—

c

CO '.c

o

in

c

<D

ol

_

<o

Q.

C

ra

1

<D

C

in

<D

a 

a

D

<D

_J

si Q.

a

D

I

1

a

D

FIGURE 11.—Occurrences and ages of Early Jurassic ammonites present in the Nelchina area of the Talkeetna Mountains and in the upper part

of the Matanuska Valley, southern Alaska.

The lowermost Sinemurian (Arietites bucklandi Zone) 

in the Arctic Coastal Plain is represented by A. cf. A 

bucklandi (Sowerby) in the Avak test well no. 1 at the 

depth of 1,836 feet (560 m). It is represented by Charmasseiceras in the South Barrow test well no. 3 at 

depths of 2,412 and 2,419.5 feet (735 and 737 m) and in 

the South Barrow test well no. 12 at depths of 2,056, 

2,061, 2,061.5 and 2,068 feet (627-630 m). The 

Sinemurian Age of Charmasseiceras in the South Barrow test well no. 3 is attested by the presence of Coroniceras sp. C (pi. 4, fig. 14) in the same well at the depth 

of 2,470 feet (753 m).

The earliest Sinemurian in the Wrangell Mountains is 

probably represented by fragmentary arietitid ammonites that occur a little below beds containing Arnioceras (figs. 9, 10). Beds of earliest Sinemurian Age in 

the Chulitna River, Seldovia, and Puale Bay areas are 

represented by Paracaloceras rursicostatum Frebold
14 EARLY JURASSIC AMMONITES FROM ALASKA

Formation

Kialagvik 

Formation

(Lower part beneath 

30 m of coarse 

conglomeratic 

beds)

Unnamed 

Lower 

Jurassic 

beds

Upper Triassic beds 

(highest part)

Generalized description

1300 ft (396 m)

Siltstone, sandy, dark gray to black, 

contains a few beds of hard buff 

sandstone, becomes sandier 

toward top, bears many limy 

concretions in upper two-thirds.

160 ft (49m)

Sandstone, conglomeratic, massive, 

tuffaceous

130 ft (40 m) 

Siltstone and sandstone, limy, partly 

tuffaceous

255 ft (78 m)

Sandstone, massive, gray, 

conglomeratic, tuffaceous

265 ft (81 m)

Sandstone and shale, limy, 

well-bedded, some limestone

245 ft (75 m)

Tuff, gray to green interbedded with 

brown limestone and agglomerate

780 ft (238 m)

Limestone, mostly thin-bedded, 

dense, dark-gray; some 

interbedded limy shale and 

tuffaceous sandstone that become 

more common toward top. Grades 

downward into upper Triassic 

beds.

320 ft (97.5 m)

Limestone, thin-bedded, dense, 

gray. Some thin beds of sandstone 

and shale

Fossil 

localities

— 21235

— ROC 1370 

— ROC 1366

_ ROC 1351 

and 1356

— 19804

— ROC 1303

Qf\f* 1 OOO

— ROC 1283 

21237

- ROC 1241 

— ROC 1240 

— 10820 (part) 

and 12396 (part)

— ? 10820 (part)

— 3110, 19803, 

25694, M1738, 

12396 (part) and 

ROC 1185

— 3109, 31370

— 19806 

— 3108

Characteristic fossils

— Inoceramus lucifer and Erycitesl

— Tmetoceras scissum and Erycitoides 

— T. scissum

— Pseudolioceras whiteevesi and Erycitoides 

— Haugia and Pseudolioceras

— Coronicerasl 

I Arnioceras

\ Paraceloceres rursicostatum and Badouxie 

canadensis

— ? Schlotheimia

— Waehneroceras, Psiloceras and 

Discamphiceras

— Waehneroceras

— Monotis cf. M. salinaria 

— Metasibirites

Stage

Upper lower 

to 

lower middle

Bajocian

Upper lower 

Bajocian 

(Aalenian)

Upper lower 

Toarcian

Lower 

Sinemurian

? 

Hettangian

Upper 

Norian

FIGURE 12.—Occurrences and ages of ammonites present in unnamed Lower Jurassic beds on northeast side of Puale Bay, Alaska Peninsula.
AGES AND CORRELATIONS 15

Arctic Coastal Plain 

in subsurface of 

Point BarrowCape Simpson area

Old Rampart area 

in east-central Alaska

Ignek Valley to Aichilik River 

area in northeastern Alaska

DeLong Mountains area 

in northwestern Alaska

Ipnavik-Anaktuvuk Rivers 

area in north-central Alaska

Kingak Shale (part) 

300 ft (91 m) 

Dark gray clay 

shale and 

claystone

Thickness unknown 

Clay shale and 

limestone 

concretions

Kingak Shale (part) 

426 ft (130 m) 

Clay shale, siltstone, 

and minor 

glauconitic sandstone Glenn Shale (part) 

1000 ft (305 m) Shale 

siltstone sandstone

Kingak Shale (part) 

214ft (65 m 

in Barrow test 

well 3

60 ft (18 m) or less 

Siliceous claystone 

some chert 

and limestone

Exact age span 

unknown because 

of lack of 

fossil evidence Kingak Shale (part) 

600ft (183 m) 

Fissile, black, 

papery shale

Kingak Shale (part) 

195 ft (59m) 

Clay shale 

and claystone

Glenn Shale (part) 

(included with above

FIGURE 13.—Correlation of Lower Jurassic rocks in northern and east-central Alaska.

(1967b, p. 26, pi. 7, figs. 1, 2; pi. 9, fig. 1). That species in 

the Chulitna River area occurs with Psiloceras 

canadense Frebold (1951, p. 3, pi. 6, figs. 1-6; pi. 2, fig. 1; 

pi. 3, fig. 1) which is now assigned to Badowxia Guex and 

Taylor (1976, p. 525). Those species of Paracaloceras 

and Badouxia in association with others in north-central 

British Columbia were tentatively assigned a middle 

Hettangian Age by Frebold (1967b, p. 31). Later studies 

by Guex and Taylor (1976) show, however, that 

Paracaloceras and Charmasseiceras in many parts of 

the world are associated with ammonites of early 

Sinemurian Age as young as the Arnioceras 

semicostatum zone. Such an age for those genera in 

British Columbia is confirmed by their association with 

Vermiceras multicostatum (Frebold), which genus is 

characteristic of the earliest Sinemurian.

The lower Sinemurian zone of Arnioceras 

semicostatum is represented in four areas in Alaska by a 

finely ribbed species of Arnioceras similar to A. densicosta (Quenstedt). In the Seldovia area, the same zone 

is probably represented by the subgenus Coroniceras 

(Paracoroniceras), which is not known in younger zones.

The next three younger Sinemurian zones, although 

not identified faunally, could be represented by poorly 

fossiliferous beds, or in part by the presence of the 

genus Arnioceras, which in Europe ranges upward 

through most of the Asteroceras obtusum Zone.

The uppermost Sinemurian zone of Echioceras 

raricostatum is represented in both the Wrangell and 

Talkeetna Mountains by Paltechioceras cf. P. 

harbledownense (Crickmay) in association with species of 

Crucilobiceras that closely resemble described species
16 EARLY JURASSIC AMMONITES FROM ALASKA

Wrangell Mountains

in

southern Alaska

Talkeetna Mountains 

Nelchina area 

southern Alaska

Chulitna River area

in Healy (A-6) quadrangle,

south-central part

of Alaska Range

Seldovia area

on the

Kenai Peninsula

Puale Bay area

on the

Alaska Peninsula

Lubbe Creek Formation 

100-300 ft (30.5-91.5m) 

Gray spiculite chert. 

Some bioclastic 

coquina near top

Upper member 

of McCarthy 

Formation 

2000-2500 ft 

(610-762 m) 

Mostly dark gray, 

thin- to mediumbedded, finely 

laminated organic 

chert and spiculite. 

Some fissile shale 

and limestone that i most common in 

upper part

All contacts 

are gradational

1500 ft (457 m) 

Tuffaceous 

sandstone and 

siliceous lutite

2300 ft (701 m) 

Tuffaceous, 

marine beds; 

thick-bedded tuff 

and agglomerate

8000 ft (2438 m) 

Volcanic rocks

2500 ft (762 m) 

Marine tuff 

tuffaceous 

sandstone and 

siliceous 

lutite

1000-5000 ft 

(305-1524 m) 

Marine lutite, 

sandstone, marl, 

tuff, limestone, 

and lava flows

Not exposed

No fossil data

Massive tuffaceous 

argillite

No fossil data

Gray calcareous 

sandstone and 

silty limestone

Kialagvik Formation 

Lower 200 ft (62 m) 

Sandy siltstone. 

Rests sharply on 

Sinemurian beds

No fossil data 

\. \ \ \ 

Absence probably 

due to faulting 

rather than 

to erosion

No fossil data

2000-3000 ft (610-915m) 

Red to green lava, tuff, 

agglomerate and sandstone. Some gray 

limestone

1040ft (317 m) 

Massive conglomeratic 

sandstone and 

siltstone

780 ft (238 m) 

Limestone, dense, 

thin-bedded; some limy 

shale. Grades downward into 

Triassic beds.

FIGURE 14.—Correlation of Lower Jurassic rocks in southern Alaska.

from western Europe. Paltechioceras occurs also in the 

Chulitna River area in association with Arctoasteroceras 

jeletzkyi Frebold, whose type specimens in arctic 

Canada were collected along with Oxynoticeras oxynotum (Quenstedt) below beds containing echioceratid 

ammonites. This shows that Arctoasteroceras occurs in 

the highest two zones of the Sinemurian.

Other mollusks of some age significance during 

Sinemurian time include the bivalves Otapiria tailleuri 

Imlay and Entolium! semiplicatum Hyatt. Of these, 0. 

tailleuri in the subsurface of northern Alaska occurs in 

the South Barrow test well No. 3 at depths of 

2,412-2,417 feet (735 m) and in the South Barrow test 

well No. 12 at depths of 2,055-2,078.5 feet (627-634 m). 

Comparisons with the ammonite occurrences in those 

test wells (table 2) show clearly that 0. tailleuri is

associated with ammonites of early Sinemurian Age, occurs above ammonites of Hettangian Age, and has its 

highest occurrence at 214 feet (65 m) below ammonites 

of late Pliensbachian Age.

Otapiria tailleuri Imlay has been found in outcrops in 

northern Alaska in a fairly thin unit of fissile clay shale 

that extends from the Ipnavik River eastward at least 

200 miles (320 km) to the Kavik River (Imlay, 1967, p. 

B6, B7; Imlay and Detterman, 1973, p. 12; Detterman 

and others, 1975, p. 44). Apparently it does not occur 

throughout the entire thickness of the shale in all areas. 

It does occur in the same rock slabs as some crushed, 

generically undeterminable ammonites (Imlay, 1967, p. 

B6). It does not occur on the same slabs as some ammonites of early Pliensbachian Age that are described 

herein as Uptonia cf. U. jamesoni (J. de C. Sowerby) and
AGES AND CORRELATIONS

TABLE 2.—Early Jurassic ammonites from well cores in northern Alaska

17

Genus and species

Depths in test wells, in feet, from which fossils were obtained

Simpson test well 1 Avak test well 1

South Barrow 

test well 3

South Barrow 

test well 12

Stages

Dactylioceras (Orthodactylites) 

cf. D. (0.) kanense McLearn. 

D. sp _____________________

Catacoeloceras sp. juv ________. 

Amaltheus margaritatus (Montfort)

A. cf. A. margaritatus (Montfort) _ 

A. stokesi (J. Sowerby) ___________

A. cf. A. stokesi (J. Sowerby) ______

A. sp __________________________

A. (Pseudoamaltheus) engelhardti

(d'Orbigny).

Arietites cf. A. bucklandi (Sowerby) 

Coroniceras sp. B _______________

Coroniceras sp. C _______________

Arnioceras sp. juv __________. 

Charmasseiceras sp. _____________

C. cf. C. marmoreum (Oppel) ______

Psiloceras (Franziceras) sp ____. 

Waehnerocerasl sp _________.

5,677; 5,680; 5,691

2,016 ___________ Lower Toarcian.

1,772; 2,017; 2,018 ___________ Do.

2,063 ___________ Do.

2,099; 2,111 ___________Upper

	Pliensbachian.

2,107 ___________ Do.

2,193; 2,198 ___________ Do.

2,186 ___________ Do.

2,069-2,184 ___________ Do.

2,090 Do.

.1,836 _________ ___________ Lower Sinemurian.

2,470

2,412; 2,419.5

1,987.4-1,987.6

2,056 

2,056

2,061.5; 2068 

2,170.5 

2,181.5

Do. 

Do. 

Do. 

Do. 

Do.

Hettangian. 

Do.

Uptonia sp. (pi. 9, figs. 9-11,17). These occurrences and 

associations in both surface and subsurface rocks show 

that the range of 0. tailleuri is probably only 

Sinemurian and that it may not be younger than early 

Sinemurian.

The other pelecypod that is useful in dating 

Sinemurian rocks is Entolium? semiplicatum Hyatt. 

(See Crickmay, 1933, p. 52, pi. 14, figs. 4-7.) That 

species to date has been found in Alaska only in the 

Wrangell Mountains, where it is common in dark-gray 

to black fissile shale at the top of the McCarthy Formation. In that shale, which is similar lithologically to the 

fissile shale in which Otapiria occurs in northern 

Alaska, it is associated with the ammonites 

Paltechioceras, (USGS Mesozoic Iocs. 30139 and 31174) 

and Crucilobiceras cf. C. crucilobatum Buckman (USGS 

Mesozoic loc. 14030) of latest Sinemurian Age. It has 

been found elsewhere in the Pacific Coast region on the 

North Fork of the American River in eastern California 

(Crickmay, 1933, p. 52; Imlay, 1968, p. C7) in association 

with Crucilobiceras. It is closely similar to and possibly 

within the range of variation of Entolium balteatum 

Crickmay (1928, p. 62, pi. 4e-g) from Parson Bay in 

British Columbia. That species is associated with 

Paltechioceras harbledownese (Crickmay) (1928, p. 61, 

pi. 4a-d), which is probably represented at the top of the 

McCarthy Formation in Alaska, (pi. 4, figs. 15-17, 22).

These data concerning Entoliuml semiplicatum and 

Otapiria tailleuri show that both are of Sinemurian Age 

and both occur in similar fissile shale. The fact that they 

have never been found associated in the same bed suggests, therefore, that they are of slightly different ages, 

or lived in somewhat different marine environments, or 

were separated by a land barrier.

PLIENSBACHIAN AMMONITES

Pliensbachian ammonites have been found in both the 

subsurface and surface in northern Alaska, in the Old 

Rampart area in east-central Alaska, and in the 

Wrangell and Talkeetna Mountains in the eastern part 

of southern Alaska. They probably occur in the Yakutat 

District in the northern part of southeastern Alaska 

(figs. 8-11).

In northern and east-central Alaska, most 

Pliensbachian ammonite occurrences consist of 

Amaltheus of late Pliensbachian Age. In the South Barrow test well No. 3, Amaltheus is represented by the 

same species in the same succession as in northwestern 

Europe (table 2). The only other ammonite of 

Pliensbachian Age found in northern Alaska consists of 

a single large specimen of Uptonia similar to U. 

jamesoni (J. de C. Sowerby) from an outcrop on 

Lisburne Ridge (USGS Mesozoic loc. 29774) between the 

Ipnavik and Etivluk Rivers in the Howard Pass 

quadrangle. This specimen is good evidence that the 

beds in which it occurs are of earliest Pliensbachian Age. 

In addition Uptonia, rather than Crucilobiceras, may be 

represented in the Ipnavik-Anatuvuk River area by 

several crushed molds (pi. 9, figs. 9-11) (USGS Mesozoic 

Iocs. 29281, 29282, and 29775) that resemble the inner 

whorls of the large specimen of Uptonia.

The Pliensbachian ammonite successions in the 

Wrangell and Talkeetna Mountains in southern Alaska 

contrast with those in northern Alaska by being fairly 

complete, by containing some ammonites that are closely similar to taxa in the Mediterranean region, and by 

the genus Amaltheus being represented by only two 

specimens from a single locality. In the Wrangell Mountains the Uptonia jamesoni zone is represented by U. cf.
18 EARLY JURASSIC AMMONITES FROM ALASKA

U. dayiceroides Mouterde, which was collected withProdactylioceras italicum (Fucini) less than 100 feet (30 m) 

below the upper contact of the upper member of the McCarthy Formation (USGS Mesozoic Iocs. 28671-28673, 

28175). Most of the Tragophylloceras ibex zone is 

represented by Tropidoceras actaeon (d'Orbigny), which 

was collected with Crucilobiceras cf. C. pacificum 

Frebold about 1 m below the upper contact of the McCarthy Formation (USGS Mesozoic loc. 28534). The uppermost Pliensbachian is represented by Arieticeras at 

the top of the McCarthy Formation (USGS Mesozoic loc. 

28688) and in the overlying Lubbe Creek Formation 

(USGS Mesozoic loc. 28531).

In the Talkeetna Mountains (figs. 9, 11), the Uptonia 

jamesoni zone is represented by a well-preserved 

specimen of Apoderoceras cf. A. subtriangulare (Young 

and Bird) and a fragmentary specimen that probably 

represents Uptonia. The next two younger zones of 

western Europe are not represented by fossils, but the 

uppermost two Pliensbachian zones are represented by 

Leptaleoceras pseudoradians (Reynes), Fontanelliceras 

cf. F. fontanellense (Gemmellaro) Arieticeras cf. A. 

domarense (Meneghini), Protogrammoceras cf. P. 

paltum (Buckman), P. cf. P. argutum (Buckman), Fanninoceras kunae McLearn, and Amaltheus cf. A. stokesi 

(J. Sowerby).

TOARCIAN AMMONITES

The Toarcian is not well represented by ammonites in 

Alaska except in the Talkeetna Mountains (figs. 8, 9,11). 

In the subsurface of the arctic Coastal Plain, only the 

lowermost Toarcian (characterized by Dactylioceras) 

has been identified. In the DeLong Mountains, that 

genus is succeeded upward by Harpoceras cf. H. exaratum (Young and Bird), which succession accounts for 

about two-fifths of Toarcian time. The same species of 

Harpoceras was obtained in northeastern Alaska on a 

tributary of the Sadlerochit River (USGS Mesozoic loc. 

22081). Near Red Hill on Ignek Creek in the Mt. 

Michelson (C-4) quadrangle, was obtained Pseudolioceras cf. P. compactile (Simpson) and P. cf. P. lythense 

(Young and Bird) of late Toarcian Age at USGS 

Mesozoic loc. 23772 (Imlay, 1955, p. 89 pi. 12, figs. 17, 

18, 20, 21).

In the Talkeetna Mountains of southern Alaska, the 

lower Toarcian is represented by a similar sequence of 

Dactylioceras and Harpoceras as in northern Alaska. 

The lower upper Toarcian is represented by Haugia, 

Brodieia, and Pseudolioceras, which genera in association are good evidence for correlation with the Haugia 

variabilis Zone of western Europe. Still higher occurs 

Grammoceras, a genus that in western Europe occurs 

only in the uppermost two zones of the Toarcian.

In the Puale Bay area, the middle to lower upper Toarcian is represented by Haugia and Pseudolioceras.

AMMONITE FAUNAL SETTING

No distinct ammonite faunal province existed in 

Alaska during most of Early Jurassic time, as shown by 

the remarkable resemblance of most of the ammonites 

present to those elsewhere in the world. During late 

Pliensbachian time, a close tie with northern Europe is 

shown by the presence of Amaltheus in northern Alaska 

and in the Talkeetna Mountains of southern Alaska. At 

the same time, a close tie with the Mediterranean region 

is shown by the presence of Arieticeras in the Wrangell 

Mountains and of Arieticeras, Leptaleoceras, Fontanelliceras, and Protogrammoceras in the Talkeetna 

Mountains but not farther north. These occurrences of 

Arieticeras and Leptaleoceras in southern Alaska are 

not much farther north than their northernmost known 

occurrences in the southern Yukon (Frebold, 1970, p. 

446).

GEOGRAPHIC DISTRIBUTION

The geographic occurrences of Early Jurassic ammonites from Alaska described herein are shown on 

figures 1-6 and tables 3-6. Detailed descriptions of the 

occurrences are given in table 7.
GEOGRAPHIC DISTRIBUTION 19

TABLE 3.— Geographic distribution of Early Jurassic ammonites from outcrops in northern and east-central Alaska

[Quadrangle occurrences are listed in table 7. Numbers 5-15 are keyed to area numbers in figure 1. Higher numbers are USGS Mesozoic locality numbers]

Northwestern Alaska

Belong Mountains

Clay shale

5

CT> o r-i m to

LO CD CD CD t- 

(M <M tN M (M

6

5 S § g

North-central 

Alaska

Claystone

7

m 

S

8

•^

S

9

I-H IM

oo oo

IM IM

CT> CT> 

IM IM

Northeastern 

Alaska

Kingak shale

10

IM [- 

[-

mIM

11

oo 

§

IM

12

1C 

CO

T-H

01 

IM

13

s

1

East-central Alaska

Old Rampart area

Glenn shale 

(in part)

14

t- 00 OS O IM M

t- t- t- t- t- CO5 <J5 OS <J5 OS OS W IM IM IM IM IM

15

3

m 

os

IM

Psiloceras sp ________________. 

P.? sp _____________________.

P. (Franziceras) sp _____________. 

P. (F.) cf. P. (F.) ruidum (Buckman) ____. 

Uptonia cf. U. jamesoni (J. de C. Sowerby). 

Uptonial sp _________________. 

Amaltheus margaritatus (Montfort) ____. 

A. stokesi (J. Sowerby) ___________. 

A. cf. A. stokesi (J. Sowerby) ________. 

A.

XXX _

sp

Dactylioceras (Orthodactylites) cf. D. (0.) directum Buckman. 

Harpoceras cf. H. exaratum (Young and Bird) ________. 

Eleganticeras sp. juv _______________________. 

Pseudolioceras cf. P. compactile (Simpson) __________. 

P. cf. P. lythense (Young and Bird) _______________.
20 EARLY JURASSIC AMMONITES FROM ALASKA

TABLE 4.—Geographic distribution of Early Jurassic ammonites in the Yakutat area and in the Wrangell Mountains in southern Alaska

[Quadrangles are listed in table 7. Numbers 16-19 are keyed to generalized area numbers in figure 1. Higher numbers are USGS Mesozoic locality numbers]

Wrangell Mountains

Yakutat 

area

Genus and species

Not 

named

16

Chitina Mountain area, 

McCarthy (C-4) quadrangle

Upper Member of 

McCarthy Formation

17

McCarthy area between headwaters of

Nizina River and Kennicott Glacier

in McCarthy (C-4) quadrangle

Lubbe

Creek

Formation

Upper Member of McCarthy Formation

18

-*lOf-OOOOOO-*

Headwaters 

of Lakina River 

McCarthy (C-7)

quadrangle

19

Cg F- 00 O5 O

"^OOOOOOOOOOOOOOOOOOOOOiasOSrHi—«"3"OO_ _ 

i—(CgCgcgcgWC^C^C^INtMC^INtMCOCOrHCOCOCOCO

Psiloceras cf. P. planorbis (J.

de C. Sowerby) _______ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ — — ~ _

Discamphiceras sp ______ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Arnioceras cf. A. densicosta

(Quenstedt) _________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ x _ _ _ _ _ _ _ _ _ _ _ __ — — x

Coronicerasl sp ________ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ — — — __

Arietitid genus undetermined _ _ _ _ _ _ x x _ _ _ _ _ _ _ _ _ _ _ _ _ _ x x x x _ _ _ x x _ x

Paltechioceras cf. P. harbledownense (Crickmay) ____ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ x _

P.? sp ______________ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ x __ __ __ __ __ __ __ __ __ x __

Crucilobiceras cf. C. crucilobatum Buckman _______ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _

C. cf. C. pacificum Frebold __ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ — — — _

C. sp ______________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Uptonia cf. U. dayiceroides

Mouterde ___________ _ x x x x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ — __ __ _

Uptonia"! sp. A _________ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Tropidoceras actaeon

(d'Orbigny) __________ __ __ __ __ __ __ __ __ __ __ __ __ __ x __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __

Prodactylioceras italicum

italicum (Fucini) ______ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

P. cf. P. italicum fucini

R. Fischer __________ _ x x _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _

P.? sp ______________ __ __ __ __ __ __ __ __ __ __ x __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ — — — __

Arieticeras cf. A. domarense

(Meneghini) _________ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _

A. cf. A. algovianum (Oppel) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _

A. sp __———_________ __ __ __ __ __ __ __ __ __ x __ __ __ __ __ __ __ __ __ __ __ __ — — — — — — — — — —
GEOGRAPHIC DISTRIBUTION 21

TABLE 5.-Geographic distribution of Early Jurassic ammonites in the Talkeetna Mountains in southern Alaska

[Quadrangle occurrences are listed in table 7. Numbers 20-23 are keyed to generalized area numbers in figure 1. Higher numbers are USGS Mesozoic locality numbers]

Talkeetna Mountains

Genus and species

Western 

Copper 

River 

basin

Sheep Mountain 

to Horn Mountain

ChickaloonKings Mountain 

area

Oshetna River 

headwaters

Talkeetna Formation

1O 1O 1O

a> o 10 r-< <£> t~ t~ O5

(M i—I O3 CO

Paltechioceras cf. P. harbledoumense (Crickmay) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _._ _ _ _ _ _ x _ x

C. cf. C. densinodulum Buckman _________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _

C. cf. C. muticum (d'Orbigny) ___________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x x x

C. cf. C. submuticum (Oppel) ___________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ x _ _

C. sp. juv ———____________________ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ x __ __ __

Apoderoceras cf. A. subtriangulare (Young

and Bird) _____________________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x x _ _ _ _ _ _ _

Fanninoceras kunae McLearn ___________ _ x x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _

F. cf. F. carlottense McLearn ___________ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _

Uptonial sp. B ____________________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _

Amaltheus cf. A. stokesi (J. Sowerby) ______ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _

Dactylioceras cf. D. commune (J. Sowerby) ___ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _

D. (Orthodactylites) kanense McLearn ______ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _

Arieticeras cf. A. domarense (Meneghini) ____ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ x _ _ _ _ _

Leptaleoceras pseudoradians (Reynes) ______ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _

Fontanelliceras cf. F. fontanellense (Gemmellaro) _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ x _ _ _ x _ _ _ _ _

Harpoceras cf. H. exaratum (Young and Bird) __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _

Protogrammoceras cf. P. paltum (Buckman) —— — — x — — — __ — — — — — — x — x — — — — — — — — — —

P. cf. P. argutum (Buckman) ___________ _ _ x _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _

Pseudolioceras sp __________________ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Grammoceras sp __________________ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Phymatocerasl sp __________________ _ _ _ _ _ _ _ x _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Brodieia cf. B. tenuicostata var. nodosa

(Jaworski) _____________________ _ _ _ _ _ _ _ _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _

Haugia cf. H. grandis Buckman _________ _ _ _ x x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

H. cf. H. variabilis (d'Orbigny) __________ _ _ _ _ _ _ _ _ x _ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _

H. cf. H. compressa Buckman ___________ _ _ _ _ x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

H. sp ___——____________________ __ __ __ __ __ __ x __ __ x __ x __ __ __ __ __ __ __ __ __ __ __ __ __ __
22 EARLY JURASSIC AMMONITES FROM ALASKA

TABLE 6. -Geographic distribution of Early Jurassic ammonites in the Chulitna River area of the Alaska Range, in the Seldovia

[Quadrangle occurrences are listed in table 7.

South-central part of Alaska Range

Chulitna River area 

Healy A-6 quadrangle

Talkeetna 

B-6 and 

C-6 quadsrangles

Sandstone, siltstone, 

Genus and species limestone, and argillite

24

i 1 g 1 1 i 1 i

r-ICOCOCOCOCOCOCO

25

t- 00 O O O CrO O 1-H 

CO CO CO

Kenai Peninsula

Seldovia area

Volcanic rocks, sandstone, limestone

26

(M •** 00 •** t- O 00

OJ(MIM<M(MCOCOCOCOCO

O 

1C<x>

CO

Lytoceras sp ___________________. 

Psiloceras cf. P. planorbis (J. de C. Sowerby) _. 

P. (Franziceras) cf. P. (F.) ruidum (Buckman). 

Discamphiceras cf. D. toxophorum (Buckman). 

Laqueoceras cf. L. sublaqueus (Waehner) ___. 

Waehneroceras cf. W. tenerum (Neumayr) __. 

W. cf. W. portlocki (Wright) _________. 

Scholtheimia sp _________________. 

Badouxia canadensis (Frebold) _________. 

B. columbiae (Frebold) ______________. 

Charmasseiceras cf. C. marmoreum (Oppel) _. 

Coroniceras sp. A ________________. 

Coronicerasl sp _________________. 

C. (Paracoroniceras) sp _____________. 

Arnioceras cf. A. densicosta (Quenstedt) ___. 

Paracaloceras rursicostatum Frebold ____. 

Arietitid genus undetermined _________. 

Arctoasteroceras jeletzkyi Frebold ______. 

Paltechioceras (Orthechioceras!) sp ______. 

Pseudolioceras sp ________________. 

Haugia cf. H. grandis Buckman ________. 

H. cf. H. compressa Buckman _________.

x x _ x x
GEOGRAPHIC DISTRIBUTION 23

area of the Kenai Peninsula, and in the Puale Bay-Alinchak Bay and Wide Bay areas of the Alaska Peninsula

Higher numbers are USGS Mesozoic locality numbers]

Alaska Peninsula

Puale Bay-Alinchak Bay area

Wide 

Bay 

area

Limestone, shale, siltstone, sandstone, 

and massive conglomerate

i>] tr- O5 O5 o CD " c- cN <N <M

X X __ X

X X

X

X __ X __ __ X __ X __ X

X X X X X

X

X

X __ __ __ __ __ X

X

X
24 EARLY JURASSIC AMMONITES FROM ALASKA

TABLE 7 .—Description of Lower Jurassic fossil localities in Alaska

[Leaders (__), number not assigned]

Locality No. 

(figs. 2-6)

USGS 

Mesozoic 

loc. No.

Collector's 

field No.

Collector, year of collection, description of locality, 

and stratigraphic assignment

5_______29159. .AF1024.

5 _______ 29160 ____ AF1025_

5 _______ 29161. .AF1027_

5 _______ 29163 ____ AF1028_____

5 _______ 29776 ____ 68ATo46F __

6 _______ 29164. . AF26_

6 _______ M2441____64ATY204F _

7___ . 29775 ____ 68ATo23____

. 29774 ____ 68ATo21d___

9 _______ 29281. . 65ATrl23B _

9 _______ 29282 ____ 65ATrl49.4 _

10 ______ 23772 ____ 50AGr61.

Simpson test well 1, lat 70°57'05" N., long 155°21' 

45" W., Cape Simpson area, Barrow (A-2) 

quadrangle northern Alaska. Kingak Shale at 

depths of 5,677-5,691 ft (1,730-1,735 m). Late 

Pliensbachian.

Avak test well, lat 71°15'02" N., long 156°28'06" 

W., Point Barrow area, Barrow (B-4) quadrangle, northern Alaska. Kingak Shale at depths 

of 1,836 ft (660 m). Early Sinemurian.

South Barrow test well 3, lat 71°15'51" N., long 

156°37'55" W., Point Barrow area, Barrow 

(B-4) quadrangle, northern Alaska. Kingak 

Shale at depths of 1,772-2,470 ft (540-753 m). 

Early Sinemurian to early Toarcian.

South Barrow test well 12, lat 71°14'18" N., long 

156°20'06" W., Point Barrow area, Barrow 

(A-4) quadrangle, northern Alaska. Kingak 

Shale at depths of 1,987.4-2,181.5 ft (606-665 

m). Hettangian to early Sinemurian.

British Petroleum (Alaska) Inc., 1964. On north 

bank of Thetis Creek headwaters, lat 68°41'51" 

N., long 164°45'05" W., north side of Delong 

Mountains, Delong Mts. (C-5) quadrangle, 

northern Alaska. Kingak Shale. Early to middle 

Toarcian.

British Petroleum (Alaska) Inc., 1964. Near USGS 

Mesozoic loc. 29159. Kingak Shale. Early to 

middle Toarcian.

British Petroleum (Alaska) Inc. 1964. Near USGS 

Mesozoic loc. 29159. Kingak Shale. Early to 

middle Toarcian.

British Petroleum (Alaska) Inc., 1964. Near USGS 

Mesozoic loc. 29159. Kingak Shale. Early to 

middle Toarcian.

I. L. Tailleur and H. A. Tourtelot, 1968. Cutbank 

on large eastern tributary of Thetis Creek (near 

USGS Mesozoic loc. 29159), lat 68°40.8' N., long 

164°45.5' W., Kingak Shale. Early to middle 

Toarcian.

British Petroleum (Alaska) Inc., 1964. North side 

of DeLong Mountains, on east bank of Ipewik 

River, lat 68°40' N., long 164°13' W., DeLong 

Mts. (C-4) quadrangle, northern Alaska. Unnamed beds. Late Pliensbachian.

I. L. Tailleur, 1964. On Ipewik River on north side 

of Delong Mountains near USGS Mesozoic loc. 

29164, lat 68°37' N., long 164°11' W., northern 

Alaska. Unnamed beds. Late Pliensbachian.

I. L. Tailleur and H. A. Tourtelot, 1968. Cutbanks 

on east side of Ipnavik River, lat 68°40.6' N., 

long 157°03.5' W., Howard Pass quadrangle, 

northern Alaska. Unnamed oil shale overlying 

Shublik Formation (Triassic). Early Pliensbachian or latest Sinemurian.

I. L. Tailleur and H. A. Tourtelot, 1968. Blankenship Creek in Lisburne Ridge area, lat 68°37.5' 

N., long 156°42.5'W., Howard Pass quadrangle, 

northern Alaska. Unnamed oil shale overlying 

Triassic Shublik Formation. Early Pliensbachian.

I. L. Tailleur, 1965. East wall of Tiglukpuk Creek 

on south flank of Tiglukpuk anticline, lat 

68°21'15" N., long 151°52'30" W., Chandler 

Lake quadrangle, northern Alaska. Unnamed 

beds overlying Shublik Formation. Early Pliensbachian or latest Sinemurian.

I. L. Tailleur, 1965. Southwest wall of Firestone 

Creek, a tributary of Tiglukpuk Creek, just 

north of mountain front, lat 68° 1815" N., long 

151°48'00" W., Chandler Lake quadrangle, 

northern Alaska. Float from unnamed beds 

overlying Shublik Formation. Early Pliensbachian or latest Sinemurian. i

R. W. Imlay, George Gryc, and Allan Kover, | 

1950. Near Red Hill on Ignek Creek, lat 69°36' j

TABLE 7.—Description of Lower Jurassic fossil localities in 

A laska—Continued

Locality No.

lf\<ra (tigs. 9 2-6)M

]oc No

Collector's 

field No.

Collector, year of collection, description of locality, 

and stratigraphic assignment

11 ______ 22081 ____ 48ASal46__

. 29165 ____ AG525_

13 ______ 30074 ____ 71ADt330c__

14 _ __ 29737 ____ 63ABe47B __

. 29738 ____ 67ARr-337a_

.29739.

.29740.

.29742. 

.'29743.

.29340.

. 67ARr-337d_ 

. 67ARr3371-n

. 67ARr337e-h. 

. 67ARr337q-s. 

. KP0688_____

16 ______ 29773 ____ 68APs54F __

. 28671 ____ 62AMK-66__

.28672.

. 28673.

. 62AMK-66A 

62AMK-67__

17 ______ 28675 ____ 62AMK-69__

N., long 146°06' W., Mt. Michelson (C-4) 

quadrangle, northern Alaska. Kingak Shale. 

Late Toarcian.

E. G. Sable, 1948. About 1 mile (1.6 km) northeast 

of mouth of Fire Creek and 0.4 mi (0.6 km) 

above the mouth of a south-flowing tributary of 

the Sadlerochit River, Mt Michelson (C-2) 

quadrangle, northern Alaska. Kingak Shale, 

within middle third and about 1,700 ft (518 m) 

above its base in black earthy shale. Early to 

middle Toarcian.

British Petroleum (Alaska) Inc., 1964. Three miles 

(4.8 km) east of Lake Schrader, lat 69°22' N., 

long 144°28' W., Mt. Michelson (B-2) 

quadrangle, northern Alaska. Kingak Shale. 

Late Pliensbachian.

R. L. Detterman, 1971. Cutbank on west side of 

Aichilik River about 2 mi (3.2 km) N. 30° E. of 

VABM ATTE on northern front of Brooks 

Range, lat 69°33' N., long 143°05' W., Barter 

Island (C-4) quadrangle, northern Alaska. 

Kingak Shale, 800 to 1,000 ft (244 to 205 m) 

above base. Late Pliensbachian.

W. P. Brosge, 1963. Spike Mountain, about 3 

miles (48 km) north of Old Rampart, lat 

63°35.75' N., long 141°40' W., Porcupine River 

area, Coleen quadrangle, east-central Alaska. 

Glenn Shale (in part). A thin unit of red conglomeratic sandstone interbedded with black, 

fine-grained quartzitic sandstone. Early Hettangian.

W. P. Brosge, 1967. Same location as USGS 

Mesozoic loc. 29737. Fossils from apparent top 

of 120 ft (36.6 m) of beds overlying granite. Early Hettangian.

Same data as Mesozoic loc. 29738 but from 20 ft 

(6 m) below apparent top. Early Hettangian.

Same data as Mesozoic loc. 29738 but from 40 ft 

(12 m) below apparent top. Early Hettangian.

Same data as Mesozoic loc. 29738 but from 80 ft 

(24 m) below apparent top. Early Hettangian.

Same data as Mesozoic loc. 29738 but from 100 ft 

(30.5 m) below apparent top. Early Hettangian.

British Petroleum (Alaska) Inc. Float from river 

bluff in the middle fork Salmon Trout River 

about 9 miles (14.4 km) east southeast of Old 

Rampart in Porcupine River area, Coleen 

quadrangle, east-central Alaska. Glenn Shale (in 

part). Noncalcareous, pyritic, thin-bedded 

mudstone interbedded with dark-gray papery 

shale exposed on bluff. Late Pliensbachian.

George Plafker, 1968. Float from sec. 34, T. 23 S., 

R. 35 E., Yakutat (D-4) quadrangle, 

southeastern Alaska. Yakutat Group. Probably 

early Pliensbachian rather than late 

Sinemurian.

E. M. MacKevett, Jr., 1962. On ridge in southcentral part of sec. 23, T. 4 S., R. 16 E., McCarthy (C-4) quadrangle, Wrangell Mountains, 

southern Alaska. Upper member of McCarthy 

Formation. Less than 100 ft (30.5 m) 

stratigraphically below the Lubbe Creek Formation. Early Pliensbachian.

E. M. MacKevett, Jr., 1962. Same description as 

Mesozoic loc. 28671 and same age.

E. M. MacKevett, Jr., 1962. Collected slightly east 

of Mesozoic loc. 28671 at the same stratigraphic 

position.

E. M. MacKevett, Jr., 1962. West-central part of 

NWV4SWV4 sec. 23, T. 4 S., R. 16 E., at altitude 

of 6,300 ft (1,920 m), McCarthy (C-4) 

quadrangle, Wrangell Mountains, southern 

Alaska. Upper member of McCarthy Formation, 

less than 100 ft (30.5 m) stratigraphically below 

Lubbe Creek Formation. Early Pliensbachian.
GEOGRAPHIC DISTRIBUTION 25

TABLE 7.—Description of Lower Jurassic fossil localities in 

A laska— Continued

Collector's Collector, year of collection, description of locality, 

field No. and stratigraphic assignment

Locality No. 

(figs. 2-6) joc NO

17 ______ 28677 ____ 62AMK-88__ E. M. MacKevett, Jr., 1962. Near center of NWVi

sec. 24, T. 4 S., R. 16 E., McCarthy (C-4) 

quadrangle, Wrangell Mountains, southern 

Alaska. Upper member of McCarthy Formation. 

Float from impure limestone near an intraformational fault. Early Sinemurian.

17______29870____67AWK-112_ E. M. MacKevett, Jr., 1967. On north side of

Chitistone Mountain in east-central part of 

NE'ANW'A sec. 27, T. 4 S., R. 16 E., McCarthy 

(B-4) quadrangle, Wrangell Mountains, 

southern Alaska. Upper member(?) of McCarthy 

Formation. Hettangian.

17______29890____67AWK-113_ E. M. MacKevett, Jr., 1967, near Mesozoic loc.

29870 in same quarter of a quarter section and 

same stratigraphic position. Hettangian.

17 ______ 29891 ____ 67AMK-233_ E. M. MacKevett, Jr., 1967. NEV4NWV4 sec. 26, T.

4 S., R. 16 E., McCarthy (B-4) quadrangle, 

Wrangell Mountains. Upper member of McCarthy Formation, a few hundred feet (100 m) 

above base of member. Hettangian.

18______14030 ____27AM-F5__ F. H. Moffit, 1927. McCarthy Creek valley, near

creek on east side, 2.5 mi (4 km) from the 

glacier, NE'ANEVi sec. 36, T. 3 S., R. 14 E., McCarthy (C-5) quadrangle, Wrangell Mountains, 

southern Alaska. Upper member of McCarthy 

Formation, probably a few hundred feet (100 m) 

above base. Late Sinemurian.

18 ______ 28531 ____ 19946-39 __ Standard Oil Co. of California. East of McCarthy

Creek near center sec. 25, T. 3 S., R. 14 E., McCarthy (C-5) quadrangle, Wrangell Mountains, 

southern Alaska. Lubbe Creek Formation. Late 

Pliensbachian.

18 ______ 28533 ____F-6_____ E. M. MacKevett, Jr., 1961. SE'ANE'ANW'A sec.

2, T. 4 S., R. 14 E., McCarthy (C-5) quadrangle, 

Wrangell Mountains, southern Alaska. Upper 

member of McCarthy Formation. About 1,000 ft 

(305 m) stratigraphically above base of member. 

Early Sinemurian.

18______28534____F10_____ E. M. MacKevett, Jr., 1961. On ridge west of

McCarthy Creek, SW1ANW1ANW1A sec. 26, T. 3 

S., R. 14 E., McCarthy (C-5) quadrangle, 

Wrangell Mountains, southern Alaska. Upper 

member of McCarthy Formation, a few feet 

(about 1 m) below upper contact. Early 

Pliensbachian.

18______ 28535____ F4______ E. M. MacKevett, Jr., 1961. South-central part

NW'ASE'A sec. 11, T. 4. S., R. 15 E., McCarthy 

(C-5) quadrangle, Wrangell Mountains, 

southern Alaska. Float from upper member of 

McCarthy Formation. Early Sinemurian.

18______28537____ F36_____ E. M. MacKevett, Jr., 1961. NE. cor. sec. 16.,

T. 4 S., R. 15 E., McCarthy (C-5) quadrangle, 

Wrangell Mountains, southern Alaska. Upper 

member of McCarthy Formation; probably in 

middle part of member. Early Sinemurian. 

18______28538____F35_____ E. M. MacKevett, Jr., 1961. A little south of

USGS Mesozoic loc. 28537. Early Sinemurian.

18 ______ 28540 ____ F45_____ E. M. MacKevett, Jr., 1961. NW1ASW1/4NE 1/4 sec.

9, T. 4 S., R. 15 E., McCarthy (C-5) quadrangle, 

Wrangell Mountains, southern Alaska. Float 

collected about 400 ft (122 m) below top of upper 

member of McCarthy Formation. Early 

Pliensbachian.

18______ 28678____ 62AMK-20__ R. W. Imlay, 1962. Southwest of West Fork in

NE. cor. NWV4 sec. 3, T. 4 S., R. 15 E., McCarthy (C-5) quadrangle, Wrangell Mountains, 

southern Alaska. Lubbe Creek Formation. Early Toarcian(?)

18 ______ 28688 ____ 62AMK-143_ E. M. MacKevett, Jr., 1962 West of Nizina River

in SE1ANW1ASW1A sec. 16, T. 3 S. R. 16 E., McCarthy (C-5) quadrangle, Wrangell Mountains, 

southern Alaska. Near top of upper member of 

McCarthy Formation. Late Pliensbachian. 

18______ 28690____62AMK-16__ R. W. Imlay, 1962. In saddle on ridge between

TABLE 7.—Description of Lower Jurassic fossil localities in 

A laska—Continued

Locality No. 

(figs. 2-6)

USGS 

Mesozoic 

loc. No.

Collector's Collector, year of collection, description of locality, 

field No. and stratigraphic assignment

18 ______ 28704 ____ 62AMK-62A

18 _ __ 28706 ____ 62AMK-63.

18 ______ 29118 ____ 64AMK-82.

. 29119 ____ 64AMK-84.

18 ______ 29121 ____ 64AMK-108_

18______31174 .63AWz-150.

18______31175. .63AWz-152_

19 ______ 14472 ____ 28AM-F9___

19 ______ 30137 ____ 71AMK-31E

19______30138. . 71AMK-36B

19______30139. . 71AFd-263B

19______30140 . 71AFd264___

20 ______ 25939 ____ 55AGzl82.

Lubbe Creek and Diamond Creek east of McCarthy Creek, in east-central part of NE'A sec. 7, T. 

4 S., R. 15 E., McCarthy (C-5) quadrangle, 

Wrangell Mountains, southern Alaska. Upper 

member of McCarthy Formation. Probably late 

Sinemurian.

E. M. MacKevett, Jr., 1962. West of McCarthy 

Creek opposite Lubbe Creek on ridge in eastcentral part of SWV4 sec. 35, T. 3 S., R. 14 E., 

McCarthy (C-5) quadrangle, Wrangell Mountains, southern Alaska. About 1,200 ft (366 m) 

above base of upper member of McCarthy Formation. Probably late Sinemurian.

E. M. MacKevett, Jr., 1962. On ridge west of 

McCarthy Creek near center NWViNWA sec. 

35, T. 3 S., R. 14 E., McCarthy (C-5) 

quadrangle, Wrangell Mountains, southern 

Alaska. In upper part of upper member of McCarthy Formation. Early Sinemurian.

E. M. MacKevett, Jr., 1964. South-central part of 

SWV4NWV4 sec. 35, T. 4 S., R. 15 E., McCarthy 

(B-5) quadrangle, Wrangell Mountains, 

southern Alaska. Transitional beds at base of 

upper member of McCarthy Formation. Early 

Sinemurian.

E. M. MacKevett, Jr., 1964. 300 ft (91.5 m) 

southeast of USGS Mesozoic loc. 29118 in same 

quarter of a quarter section. Transitional beds 

at base of upper member of McCarthy Formation. Early Sinemurian.

E. M. MacKevett, Jr., 1964. In area of small folds 

40 ft (12 m) S. 60° W. of summit of Hill 6580. 

NEV4NEV4 sec. 34, T. 4 S., R. 15 E., McCarthy 

(B-5) quadrangle, Wrangell Mountains, 

southern Alaska. Low in upper member of McCarthy Formation. Early Sinemurian.

E. M. MacKevett, Jr., 1963. On ridge between 

Root Glacier and Kennicott Glacier. NEV4SWV4 

sec. 19, T. 3 S., R. 14 E., McCarthy (C-16) 

quadrangle, Wrangell Mountains, southern 

Alaska. Upper member of McCarthy Formation, 

150 ft (46 m) below top. Late Sinemurian.

E. M. MacKevett, Jr., 1963. Same location as 

USGS Mesozoic loc. 31174 but only 100 ft (30.5 

m) below top of upper member of McCarthy Formation. Late Sinemurian.

F. H. Moffit, 1928. Head of first northern tributary of Mill Creek, SE'A sec. 33, T. 3 S., R. 11 

E., McCarthy (C-7) quadrangle, Wrangell 

Mountains, southern Alaska. Upper member of 

McCarthy Formation. Late Sinemurian.

E. M. MacKevett, Jr., 1971. Center of NVaSW'A 

sec. 8, T. 4 S., R. 11 E., McCarthy (C-7) 

quadrangle, Wrangell Mountains, southern 

Alaska. Lower part of upper member of McCarthy Formation. Early Sinemurian.

E. M. MacKevett, Jr., 1971. SWV4NEV4SWV4 sec 

17, T. 4 S., R. 12 E., McCarthy (C-7) 

quadrangle, Wrangell Mountains, southern 

Alaska. Low in upper member of McCarthy Formation. Early Sinemurian.

A. B. Ford, 1971. On ridge in south-central part 

of SEV4NWV* sec. 17, T. 4 S., R. 12 E., McCarthy (C-7) quadrangle, Wrangell Mountains, 

southern Alaska. Low in upper member of McCarthy Formation. Late Sinemurian. 

A. B. Ford, 1971. On ridge in SW. cor. sec. 17, 

near sec. 18, T. 4 S., R. 12 E., McCarthy (C-7) 

quadrangle, Wrangell Mountains, southern 

Alaska. Early Sinemurian.

Arthur Grantz, 1955. Lat 61°54'02" N., long 

146°52'00" W., Valdez (D-8) quadrangle, south 

side of western Copper River basin, southern 

Alaska. Talkeetna Formation. Late Toarcian.
26 EARLY JURASSIC AMMONITES FROM ALASKA

TABLE 7. -Description of Lower Jurassic fossil localities in 

A laska—C ontinued

TABLE 7.—Description of Lower Jurassic fossil localities in 

Alaska—Continued

Locality No. 

(figs. 1-6)

Collector's 

fieldN°-

Collector, year of collection, description of locality, 

and stratigraphic assignment

21 ______ 24107 ____ 52AGz63____

21 ______ 24108

21 ______ 24111

21 ______ 24114

21 ______ 24787

21 _________ 25316

21 ______ 25317

21 ______ 25318

21 ______ 25319

52AGz66 _

52AGz253 ___

52AGz98 __

53AGz40

54AGz48A__

54AGz49A __

54AGz50 ____

54AGz51 __

21 ______ 25342 ____ 54AFy24____

21 ______ 25359

21 ______ 25940

21 ______ 25941

21 ______ 27508

54AFyl30 __

55AGz228a__

55AGz294 __

6-10BB_

21 ______ 29449 

21 ______ 29450

66AGz31A _ 

66AGz31B .

R. D. Hoare, R. W. Imlay, and Arthur Grantz, 

1952. On south tributary of Squaw Creek, 1.98 

miles (3.2 km) N. 28Vz° E. of southeast summit 

of Gunsight Mountain, Anchorage (D-2) quad. 

Talkeetna Mountains, southern Alaska. Talkeetna Formation. Late Pliensbachian.

Arthur Grantz, R. D. Hoare, and R. W. Imlay, 

1952. Differs from USGS Mesozoic loc. 24107 by 

being 1.91 miles (3.1 km) N. 28%° E. of 

southeast summit of Gunsight Mountain. Late 

Pliensbachian.

Arthur Grantz, R. D. Hoare, and R. W. Imlay, 

1952. 5.04 miles (8 kms) N. 33° E. of the mouth 

of Sheep Creek, Anchorage (D-2) quadrangle, 

Talkeetna Mountains, southern Alaska. Early 

Toarcian.

Arthur Grantz, R. D. Hoard, and R. W. Imlay, 

1952. From north branch of North Creek, 1.61 

miles (2.5 km) N. 45° W. of its mouth. Talkeetna 

Mountains (A-l) quadrangle, southern Alaska. 

Talkeetna Formation. Late Toarcian.

Arthur Grantz and L. F. Fay, 1953. About 0.6 mile 

(1 km) northwest of point where Camp Creek 

crosses Glenn Highway, lat 61°50'53" N., long 

147°24'43" W., Anchorage (D-2) quadrangle, 

Talkeetna Mountains, southern Alaska. Talkeetna Formation. Early Toarcian.

Arthur Grantz and L. F. Fay, 1954. Lat 62°00I42" 

N., long 147°27'49" W., Talkeetna Mountains 

(A-l) quadrangle, Talkeetna Mountains, 

southern Alaska. Talkeetna Formation, upper 

part. Late Toarcian.

Arthur Grantz and L. F. Fay, 1954. Lat 62°00'06" 

N., long 147°31'30" W., Talkeetna Mountains 

(A-2) quadrangle, Talkeetna Mountains, 

southern Alaska. Upper part of Talkeetna Formation. Late Toarcian.

Arthur Grantz and L. F. Fay, 1954. Lat 62°00'10" 

N., long 147°32'33" W., Talkeetna Mountains 

(A-2) quadrangle, Talkeetna Mountains, 

southern Alaska. Talkeetna Formation. Late 

Toarcian.

Arthur Grantz and L. F. Fay, 1954. Lat 62°0(yOO 

W N., long 147°32'45" W., Talkeetna Mountains 

(A-2) quadrangle, Talkeetna Mountains, 

southern Alaska. Talkeetna Formation. Late 

Toarcian.

L. F. Fay, 1954. Lat 62°02'48" N., long 

147°29'34" W., Talkeetna (A-l) quadrangle, 

Talkeetna Mountains, southern Alaska. Talkeetna Formation. Late Toarcian.

L. F. Fay, 1954. Lat 62°02'40" N., long 

147°21'36" W., Talkeetna Mountains (A-l) 

quadrangle, Talkeetna Mountains, southern 

Alaska. Talkeetna Formation. Late Toarcian.

Arthur Grantz, 1955. Lat 62°01'37" N., long 

147°17'53" W., Talkeetna Mountains (A-l) 

quadrangle, Talkeetna Mountains, southern 

Alaska. Talkeetna Formation. Late Toarcian.

Arthur Grantz, 1955. Lat 61°5r51" N., long 

147°21'22" W., at east end of Sheep Mountain. 

Anchorage (D-l) quadrangle, Talkeetna Mountains, southern Alaska. Talkeetna Formation, 

upper part. Late Pliensbachian.

General Petroleum Corp. 1959. Near head of 

McDougall Creek. Coordinates 15.9-0.37. 

Talkeetna Mountains (A-2) quadrangle, 

Talkeetna Mountains, southern Alaska. Talkeetna Formation. Late Toarcian.

Arthur Grantz, 1966. Same place and stratigraphic position as USGS Mesozoic loc. 24108.

Arthur Grantz, 1966. On south tributary of Squaw 

Creek, 1.95 miles (3.1 km) southeast of summit 

of Gunsight Mountain, near USGS Mesozoic loc. 

24107. Anchorage (D-2) quadrangle, Talkeetna

Locality 

(figs. 5

USGS

^°- Mesozoic 

~6) loc. No.

Collector's Collector, year of collection, description of locality, 

field No. and stratigraphic assignment

22 ______ 6706 ____ Aug. 30, 1910

. 6797 ____ Aug. 30. 1910

22.

22.

23.

.27586.

. 26772 ____ 57AGz30____

Mountains, southern Alaska. Talkeetna Formation. Late Pliensbachian.

22 ______ M6171____73APr85A __ George Plafker, 1973. On south-flowing branch of

Doone Creek, 2,000 ft (610 m) west of SE. cor. 

sec. 25, T. 21 N., R. 5 E., Anchorage (D-4) 

quadrangle, Talkeetna Mountains, southern 

Alaska. Talkeetna Formation. Early 

Pliensbachian.

A. H. Brooks, 1910. Creek entering Chickaloon 

River from west 1 mile (1.6 km) above Government Bridge at altitude of 2,000 ft (610 m). 

Coordinates 3.0-9.0. Anchorage D-4 

quadrangle, Talkeetna Mountains, southern 

Alaska. Talkeetna Formation. Late Sinemurian.

G. C. Martin, 1910. Doone Creek at mouth of 

gulch. Anchorage (D-4) quadrangle, Talkeetna 

Mountains, southern Alaska. Float from 

Talkeetna Formation. Early Pliensbachian. 

.13177-2 __ Standard Oil of California. Carbon Creek, 2.3 

miles (3.7 km) S. 7° E. of its mouth near center 

of SEV4 sec. 12, T. 19 N., R. 5 E., Anchorage 

(C-4) quadrangle, coordinates 1.4-17.3., 

Chugach Mountains, southern Alaska. Talkeetna Formation. Late Pliensbachian.

. 29198 ____ SUS62 ___ British Petroleum Expl. (Alaska) Co. From saddle 

on south side of Kings Mountain 2 Vz miles (4 

km) S. 15° E. of VABM 757 on the Glenn 

Highway. Anchorage (C-5) quadrangle. 

Chugach Mountains, southern Alaska. Talkeetna Formation. Early Toarcian.

Arthur Grantz, 1957. Lat 62°59'58" N., long 

147°57'48" W., Coordinates 1.20-17.23. 

Talkeetna Mountains (A-2) quadrangle, 

Talkeetna Mountains, southern Alaska. Talkeetna Formation. Late Sinemurian.

Arthur Grantz, 1962, on Nowhere Creek. Lat 

62°13'29" N., long 148°01'27" W., Coordinates 

15.35-15.63. Talkeetna Mountains (A-3) 

quadrangle, Talkeetna Mountains, southern 

Alaska. Talkeetna Formation. Late Sinemurian.

Arthur Grantz, 1962. On Nowhere Creek, lat 

62°13'30" N., long 148°01'18" W., Coordinates 

15.43-15.65., Talkeetna Mountains (A-3) 

quadrangle, Talkeetna Mountains, southern 

Alaska. Late Sinemurian.

Arthur Grantz, 1962. Talus and stream float, lat 

62°13'30" N., long 148°0'12" W., Coordinates 

15.5-15.65., Talkeetna Mountains (A-3) 

quadrangle, Talkeetna Mountains, southern 

Alaska. Talkeetna Formation. Late Sinemurian.

16229 ___ 32AT1___ Elmer Bedager, 1932. Head of an eastern 

tributary of Partin Creek that heads against Little Shotgun Creek on west side of Chulitna 

River valley north of Eldridge Glacier. Probably 

same place as USGS Mesozoic loc. 31262 in Healy (A-6) quadrangle, south-central part of 

Alaska Range, southern Alaska. Unnamed beds. 

Late early to early middle Sinemurian.

N. J. Silberling and D. L. Jones, 1976. On divide 

between Ohio and Copeland Creeks; 5,800 ft 

(1,768 m) N. 30° E. of VABM Copeland, Healy 

(A-6) quadrangle, south-central part of Alaska 

Range, southern Alaska. Unnamed beds. Late 

early to early middle Sineumurian.

N. J. Silberling and D. L. Jones, 1976. On divide 

between Ohio and Copeland Creek; 6,800 ft 

(2073 m) N. 39° E. from VABM Copeland, Healy (A-6) quadrangle, south-central part of 

Alaska Range, southern Alaska. Unnamed beds. 

Latest Sinemurian.

.F6-S-322__ N. J. Silberling and D. L. Jones, 1976. Divide 

between Partin and Little Shotgun Creeks in upper part of small drainage into Partin Creek, 

39,850 ft (12,147 m) S. 31.5° W. from VABM 

Copeland, Healy (A-6) quadrangle, southcentral part of Alaska Range, southern Alaska.

23 ______ 28661 ____ 62AGz84____

23 ______ 28662 ____ 62AGz84A __

23 ______ 28663 ____ 62AGz84B __

24.

24 ______ 31260 ____ F6-J-27.

24 ______ 31261 ____ F6-J-31 __

24 ______ 31262.
GEOGRAPHIC DISTRIBUTION 27

TABLE 7. -Description of Lower Jurassic fossil localities in 

A laska— Continued

TABLE 7.-Description of Lower Jurassic fossil localities in 

Alaska—Continued

Locality No. 

(figs. 2-6)

uses

Mesozoic 

loc. No.

Collector's 

field No.

Collector, year of collection, description of locality, 

and stratigraphic assignment

Unnamed calcareous sandstone. Late early to 

early middle Sinemurian.

24 ______31263 ____ F6-S-325__ N. J. Silberling and D. L. Jones, 1976. Divide

between Ohio and Shotgun Creeks 19,800 ft 

(6,035 m) S. 38° W. from VABM Copeland, Healy (A-6) quadrangle, south-central part of 

Alaska Range, southern Alaska. Unnamed beds. 

Late early to early middle Sinemurian.

24 ______ 31264 ____ F6-S-331__ N. J. Silberling and D. L. Jones, 1976. Divide

between Shotgun and Little Shotgun Creeks, 

28,800 ft (8778 m) S. 34° W. from VABM 

Copeland, Healy (A-6) quadrangle, southcentral part of Alaska Range, southern Alaska. 

Unnamed beds. Earliest Sinemurian.

24 ______ 31265 ____ F6-S-332__ N. J. Silberling and D. L. Jones, 1976. Divide

between Shotgun and Little Shotgun Creeks, 

31,000 ft (9,449 m) S. 33° W. from VABM 

Copeland, Healy (A-6) quadrangle, southcentral part of Alaska Range, southern Alaska. 

Unnamed beds. Late early to early middle 

Sinemurian.

24 ______ 31266 ____ F6-S-333__ N. J. Silberling and D. L. Jones, 1976. Crest of

ridge on east side of upper Long Creek, 32,700 

ft (9,967 m) N. 6° E. from VABM Copeland, 

Healy (A-6) quadrangle, south-central part of 

Alaska Range, southern Alaska. Unnamed beds. 

Earliest Sinemurian.

25 ______ 30907 ____ 75AR38A __ R. L. Detterman and D. L. Jones, 1975. Altitude

5,850 ft (1,768 m), 3.5 mi (5.6 km) west of 

Shellabarger Pass, sec. 12, T. 28 N., R. 20 W., 

lat 62°31'49" N., long 152°53'02" W., Talkeetna 

(C-6) quadrangle, south-central part of Alaska 

Range, southern Alaska. Unnamed beds 150 ft 

(45.7 m) below lowest Bwc/iia-bearing limestone. 

Sinemurian.

25 ______30908____ 75AR39 __ D. L. Jones, 1975. Altitude 6,100 ft (1,859 m),

5 miles (8 km) southwest of Shellabarger Pass, 

lat 62°30'20" N., long 152°55'59" W., Talkeetna 

(C-6) quadrangle, south-central part of Alaska 

Range, southern Alaska. Unnamed beds. Early 

Sinemurian.

25 ______ 31270 ____ (76 AR17)__ Bruce Reed and R. L. Detterman, 1976. Float

from 100 to 150 ft (30 to 46 m) of siltstone and 

shale exposed on north side of ridge about 1 mile 

(1.6 km) northwest of Tatina River in southcentral part of SW'ASE'A sec. 25, T. 28 N., R. 

20 W., lat 62°28'51" N., long 152°53'36" W., 

Talkeetna (B-6) quadrangle, south-central part 

of Alaska Range, southern Alaska. Early 

Sinemurian.

26 ______2978____905_____ T. W. Stanton and G. C. Martin, 1904. Point

Naskowhak, at entrance to Seldovia Bay, 

Seldovia (B-5) quadrangle, on Kenai Peninsula, 

southern Alaska. Unnamed beds. Early 

Sinemurian.

26______ 2979 ____906_____ T. W. Stanton and G. C. Martin, 1904. Threefourths of a mile (1.2 km) west of entrance to 

Seldovia Bay, Seldovia (B-5) quadrangle on 

Kenai Peninsula, southern Alaska. Unnamed 

beds. Early Sinemurian.

26 ______ 2981 ____ 907b ____ T. W. Stanton and G. C. Martin, 1904. Sea cliffs 2

miles (3.2 km) west of Seldovia Bay, eastern 

part of sec. 34, T. 8 S., R. 15 W., Seldovia (B-5) 

quadrangle, on Kenai Peninsula, southern 

Alaska. Talkeetna Formation about 200 ft (61 

m) above horizontal conglomerate. Earliest 

Sinemurian.

26 ______ 21242 ____ 48AI119__ R. W. Imlay and D. J. Miller, 1948. Sea cliffs

2.95 miles (4.7 km) S. 67° W. of Point 

Naskowhak on south shore of Kachemak Bay, 

probably NE. cor. sec. 5, T. 9 S., R. 15 W., 

Seldovia (B-5) quadrangle, on Kenai Peninsula, 

southern Alaska. Talkeetna Formation in gray 

limestone and green tuffaceous sandstone. Early Hettangian.

T USGS Locality No. Mesozoic

(figs. 2-6) ]oc NO.

Collector's 

field No.

Collector, year of collection, description of locality, 

and stratigraphic assignment

26 ______ 22664 ____ 51AGz21__ Arthur Grantz, 1951. Sea cliffs 2.8 miles (4.5 km)

west of Point Naskowhak on south shore of 

Kachemak Bay, near point on west side of sec. 

34, T. 8 S., R. 16 W., Seldovia (B-5) quadrangle, 

Kenai Peninsula, southern Alaska. Talkeetna 

Formation. Early Hettangian.

26______ 31128 ____ 75JK-77B__ J. S. Kelley, 1976. Cliff near head of small bay

southwest of Point Naskowhak in NEVtNW'A 

sec. 36, T. 15 S., R. 14 W., Seldovia (B-5) 

quadrangle, Kenai Peninsula, southern Alaska. 

Early Sinemurian.

26 _ ____ 31634 ____ 76JK-15P__ J. S. Kelley, 1976. Sea Cliffs, 1.2 miles (1.9 km)

5° SE. of Ft. Naskowhak, in NWV4SWV4 sec. 31, 

T. 8 S., R. 14 W., lat 59°26'45" N., long 

151°44'25" W., Seldovia (B-5) quadrangle, 

Kenai Peninsula, southern Alaska. Unnamed 

beds. Early Sinemurian.

26 _ ____ 31637 ____ 76JK-16J__ J. S. Kelley, 1976. Sea cliffs. 0.6 mile (0.94 km) 6°

SE. of Pt. Naskowhak in NWViNWVi sec. 31, T. 

8 S., R. 14 W., lat 59°26'71" N., long 151°44'26" 

W., Seldovia (B-5) quadrangle, Kenai Peninsula, southern Alaska. Early Sinemurian.

26 _ ____ 31640 ____ 76JK-21D __ J. S. Kelley, 1976. Sea cliffs, 0.19 mile (0.3 km) 14°

SE. of Pt. Naskowhak, NEV4SEV4 sec. 25, T. 8 

S., R. 14 W., lat 59°27'22" N., Long 151°44'50" 

W., Seldovia (B-5) quadrangle, Kenai Peninsula, southern Alaska. Unnamed beds. Early 

Sinemurian.

26____ __ 31648 ____ 76JK-38A __ J. S. Kelley, 1976. Sea cliffs, 3 miles (4.8 km) 66°

SW. of Pt. Naskowhak in NEV4SWV4 sec. 34, T. 

8 S., R. 15 W., lat 59°26'30" N., long 151°48"86" 

W., Seldovia (B-5) quadrangle, Kenai Peninsula, southern Alaska. Unnamed beds. Early 

Hettangian.

26 ______ 31650 ____ H257____ D. M. Hopkins, 1962. Sea cliffs just west of buried

valley of Miocene age, lat 59°26.6' N., long 

151°47.1' W., probably from same places as 

USGS Mesozoic loc. 2981, Seldovia (B-5) 

quadrangle, Kenai Peninsula, southern Alaska. 

Unnamed beds. Early Sinemurian.

27 ______ 3109 ____ 949 _____ T. W. Stanton, 1904. Northeast shore of Puale

Bay, about 1 mile (1.6 km) northwest of Chignik 

Point, Alaska Peninsula. A short distance 

southwest of locality 3110 and midway between 

that locality and Triassic Mesozoic loc. 19806 

that contains Monotis. Unnamed beds. Hettangian.

27______ 3110 ____ 950 _____ T. W. Stanton, 1904. Northeast shore of Puale

Bay about 1 mile (1.6 km) northwest of Chignik 

Point and 5,400 ft (1,646 m) N. 18° W. of most 

easterly point of Puale Bay, Karluk (C4-C5) 

quadrangle, Alaska Peninsula. Unnamed beds. 

Hettangian.

27 ______ 10820 ____ 1-127 ____ S. R. Capps, 1921. Northeast shore of Puale Bay

about 1 Va miles (1.8 km) northwest of Chignik 

Point. Contains Paraccdoceras as at Mesozoic 

loc. 12396 and ROC loc. 1241 but also contains 

one specimen of Schlotheimia preserved in a 

different matrix and some Late Triassic 

mollusks. Unnamed beds. Early Sinemurian 

(mostly). Some late Hettangian and Late 

Triassic.

W. R. Smith, 1923. Southwest shore Alinchak 

Bay, Karluk (D-4) quadrangle, Alaska Peninsula. Probably same place as locality ROC 3002 

and USGS Mesozoic loc. 29268. Unnamed beds. 

Early and middle Hettangian. 

W. R. Smith, 1924. Southwest side of Alinchak 

Bay at same place as Mesozoic loc. 12075. Unnamed beds, middle Hettangian.

27______12396____ F18_____ W. R. Smith, 1924. From northeast shore of

Puale Bay reportedly about 2 miles (3.2 km) northwest of Chignik Point, Karluk (C4-C5) 

quadrangle, Alaska Peninsula. Apparently obtained from different units as shown by presence

27 ______ 12075 ____ 1.

.12394____F16.
28 EARLY JURASSIC AMMONITES FROM ALASKA

TABLE 7 .—Description of Lower Jurassic fossil localities in 

A laska—C ontinued

rfi' 

(fags. 2-6)

uses

Mesoz°ic 

loc _ No_

Collector's 

field No.

Collector, year of collection, description of locality, 

and stratigraphic assignment

of Paracaloceras as at USGS Mesozoic loc. 

10820 and of Waehneroeeras as at Mesozoic 

locality 3110. Unnamed beds. Early Sinemurian' 

and late Hettangian.

27______19803____(44AKmF75)L. B. Kellum, S. N. Daviess, and C. M.

Swinney, 1944. Northeast shore of Puale Bay 1 

mile (1.6 km) northwest of Chignik Point, 

Alaska Peninsula. From dense limestone interbedded with limy shale, and some tuffaceous 

sandstone 360 ft (110 m) below base of massive 

tuff and agglomerate. Unnamed beds. Middle 

Hettangian.

27 ______19804 ____ 44 AKm F 76 L. B. Kellum, S. N. Daviess, and C. M. Swinney,

1944. On northeast shore of Puale Bay about 2 

miles. (3.2 km) north-northeast of Chignik Point 

and 1,000 ft (305 m) north of northernmost large 

waterfall, Karluk (C-4 and C-5) quadrangles, 

Alask'a Peninsula. In dark-gray shale 30 ft (9 m) 

above base of Kialagvik Formation. Near middle 

of Toarcian.

27 ______ 21237 ____ 48AI 112__ R. W. Imlay and D. J. Miller, 1948. Northeast

shore of Puale Bay, Alaska Peninsula, 1.63 miles 

(2.6 km) N. 22° W. of Chignik Point. Float probably from light-gray sandstone exposed in cliffs 

about 340 ft (103 m) below base of Kialagvik 

Formation. Unnamed beds. Early to early late 

Sinemurian.

27 ______ 25694 ____ 55AKe6 __ A. S. Keller, 1955. Southwest side of Alinchak Bay

in limestone overlying Triassic beds. Probably 

same place as 12075, 12394, and 25694. Unnamed beds. Middle Hettangian.

27 ______ 29267 ____ 65AP 175__ Marvin Mangus, 1965. Northeast shore of Puale

Bay about 1 mile (1.6 km) northwest of Chignik 

Point, Alaska Peninsula. Probably from same 

place as Mesozoic Iocs. 3110 and 19803. Unnamed beds. Middle Hettangian.

27 ______ 29268 ____ 65AMe55 __ G. W. Moore, 1965. Southwest shore of Alinchak

Bay, lat 57°45.8' N., long 155°18.9' W., Karluk 

(D-4) quadrangle, Alaska Peninsula. Unnamed 

beds. Middle Hettangian.

27 ______ M1738____ALp701M__ British Petroleum, Inc., 1962. From or near the

same place as Mesozoic Iocs. 3110 and 19803, 

3V2 miles (5.6 km) west of Cape Kekurnoi, lat 

57°43.4' N., long 155°23.5' W., east shore or 

Puale Bay, Alaska Peninsula. Unnamed beds. 

Early to middle Hettangian.

27 ______31370____ 77AI1____ R. W. Imlay, Martha Yount, Carleen Holloway,

and Fred Wilson, 1977. Northeast side of Puale 

Bay. Same place as USGS Mesozoic loc. 3109, 

about 200 ft (61 m) stratigraphically above top of 

Mo»!«h's-bearing beds, 1 miles (1.6 km) northwest of Chignik Point, Karluk (C4-C5) 

quadrangle, Alaska Peninsula. Unnamed beds. 

Hettangian.

27______31372____77AI3____ R. W. Imlay, Martha Yount, Carleen Holloway,

and Fred Wilson, 1977. Northeast side of Puale 

Bay. About 4,300 ft (1,311 m) S. 12° E. of 

VABM Bay 119. About 270 to 280 ft (82-86 m) 

stratigraphically above base of massive 

tuffaceous sandstone. Karluk (C4-C5) 

quadrangle, Alaska Peninsula. Early 

Sinemurian.

27 ______ _______ ROC 1185__ W. T. Rothwell and associates, 1962. From 1,900

ft (1,494 m) N. 30° W. of VABM 96 Hike on northeast shore of Puale Bay, Alaska Peninsula. 

Float from or near same place as localities 3110 

and 19803. Unnamed beds. Early to late Hettangian.

27 ______ _______ ROC 1240__ W. T. Rothwell and associates, 1962. From 10

ft (3 m) stratigraphically below locality ROC 

1241 and probably 270 to 280 ft (82-86 m) 

stratigraphically above base of tuffaceous sandstone. Unnamed beds. Early Sinemurian.

27 ______ _______ ROC 1241__ W. T. Rothwell and associates, 1962. Northeast

shore of Puale Bay. About 4,300 ft (1,311 m) S.

TABLE 7. —Description of Lower Jurassic fossil localities in 

Alaska—Continued

Locality No. 

(figs. 2-6)

USGS 

Mesozoic 

loc. No.

Collector's 

field No.

Collector, year of collection, description of locality, 

and stratigraphic assignment

27 _ . ROC 1282

N and S

27.

27.

27.

28.

12° E. of VABM 119 Bay, Karluk (C4-C5) 

quadrangle, Alaska Peninsula. About 700 ft (213 

m) below base of Kialagvik Formation. Unnamed beds. Early Sinemurian. 

W. T. Rothwell and associates, 1962. Same 

general location as Mesozoic loc. 19804. At point 

about 3,000 ft (914 m) S. 12° E. of VABM 119 

Bay (N = bed north of fault, S = bed south of 

fault). In massive sandstone about 290 ft (88 m) 

below the base of the Kialagvik Formation. Unnamed beds. Late early to early late 

Sinemurian.

ROC 1283__ W. T. Rothwell and associates, 1962. Same 

description as locality ROC 1282 but 10 ft (3 m) 

lower in the massive sandstone. Unnamed beds. 

Late early to early late Sinemurian.

ROC 1303__ W. T. Rothwell and associates, 1962. Same 

general location as Mesozoic loc. 19804. At point 

about 2,700 ft (823 m) S. 12° E. of VABM 119 

Bay. From unit of massive sandstone 160 ft. (49 

m) thick underlying the Kialagvik Formation. 

Unnamed beds. Sinemurian.

ROC 3002__ W. T. Rothwell and associates, 1962. South end 

of Alinchak Bay about 2.1 mi (3.3 km), N. 35° E. 

of VABM 1197 Kek, Karluk (D-4) quadrangle, 

Alaska Peninsula. Unnamed beds. Early and 

middle Hettangian.

Richfield Oil Co., Wide Bay Test Well 1, core 5 

at depth of 2,235 to 2,236 ft (681 m), at Wide 

Bay, Alaska Peninsula. Unnamed beds. Hettangian.

SYSTEMATIC DESCRIPTIONS

Family PSILOCERATIDAE Hyatt, 1867 

Genus PSILOCERAS Hyatt, 1867

Psiloceras cf. P. planorbis (J. de C. Sowerby) 

Plate 1, figures 1, 2

Ten compressed molds represent a highly evolute 

smooth ammonite similar to P. planorbis (J. de C. 

Sowerby) (1824, pi. 448; Dean and others, 1961, pi. 63, 

fig. 1; Arkell and others, 1957, p. L232, fig. 258-10, a-c) 

of early Hettangian Age. Their occurrence with 

Waehneroeeras of middle Hettangian Age in three collections implies either that some of the specimens herein 

compared with P. planorbis are of that age or that the 

collections were made from more than one stratigraphic 

unit. The presence of beds of earliest Hettangian Age in 

the areas where these collections were made is shown by 

the upward gradation of marine Upper Triassic beds into marine Lower Jurassic beds.

Figured specimens.—USNM (U.S. National Museum) 

247950, 247951.

Occurrences.—Upper member of McCarthy Formation 

at USGS Mesozoic loc. 29891 in the Wrangell Mountains; unnamed beds on the small peninsula between 

Puale Bay and Alinchak Bay, Alaska Peninsula, at 

USGS Mesozoic Iocs. 12075 and M1738 and ROC 

(Richfield Oil Co.) localities 1185 and 3002.
SYSTEMATIC DESCRIPTIONS 29

Subgenus FRANZICERAS Buckman, 1923 

Psiloceras (Franziceras) cf. P. (F.) ruidum (Buckman)

Plate 1, figures 12-14, 18-24

Twelve external molds of immature ammonites are 

fairly evolute, have a subovate whorl section that is a little higher than wide, an umbilicus that represents about 

50 percent of the diameter, and rather sharp, widely 

spaced ribs. These ribs begin near the umbilicus, trend 

radially or slightly adapically on the flanks, and terminate rather abruptly a little above the middle of the 

flanks. In addition, faint lines that trend radially on the 

flanks and arch forward on the venter are preserved on 

shelly material that occurs on a few specimens from the 

Seldovia area.

The suture line is simple, has fairly narrow saddles, 

and does not have a strongly retracted suspensive lobe.

This species differs from plicate forms of Psiloceras 

such as P. (P.) plicatum (Quenstedt) (1883, pi. 1, figs. 9, 

11; Donovan, 1952, pi. 22, figs. 1, 2; Lange, 1941, pi. 2, 

fig. 20) by having sharp ribs instead of folds. It differs 

from species of the subgenus P. (Caloceras) by being less 

e volute, by having a smaller umbilicus relative to its 

diameter, by ribs trending radially instead of projecting 

adorally, and by having a somewhat different sutural 

pattern. It appears to have somewhat weaker ribbing 

than the fragmentary specimens of Psiloceras from the 

northern Yukon that were described by Frebold and 

Poulton (1977, p. 92, 93, pi. 1 figs. 3-8). Overall it shows 

most resemblance to P. (Franziceras) ruidum Buckman 

(1923, pi. 423) but differs by having shorter ribs and a 

less retracted suspensive lobe. These differences may be 

related to its much smaller size.

It is associated at USGS Mesozoic loc. 29737 with 

small specimens of Psiloceras, of which some are smooth 

and some bear faint ribs on their innermost whorls.

Figured specimens.-USNM 247952-247955.

Occurrences,— Glenn Shale in Coleen quadrangle of 

east-central Alaska at USGS Mesozoic Iocs. 

29737-29739 and 29742; unnamed beds in the Seldovia 

area on the Kenai Peninsula at USGS Mesozoic Iocs. 

21242, 22664, and 31648.

Psiloceras (Franziceras) sp. ind.

Plate 1, figures 11, 15-17

This species is represented by two specimens. It 

differs from the species described herein as P. (F.) cf. P. 

(F.) ruidum (Buckman) by having sparser, shorter ribs 

that are much more prominent on the lower third of the 

flanks. These ribs are particularly prominent near the 

umbilical margin on the inner whorls of a specimen from 

northernmost Alaska as well as on the smaller speciment from east-central Alaska. On the outer whorl of 

the specimen from northernmost Alaska, the ribs fade 

considerably near the middle of the flanks but persist

across the venter, where they arch forward and vary 

from weak to fairly strong. In addition, fine closely 

spaced radial striae are present on some shelly material 

that is preserved on the inner whorls of the larger 

specimen. The suture line is not preserved.

Figured specimens.-USNM 247956, 247957.

Occurrences.— Glenn Shale in the Coleen quadrangle 

of east-central Alaska at USGS Mesozoic loc. 29742; 

Kingak Shale in northernmost Alaska in the South Barrow No. 12 well at the depth of 2,170.5 feet (661.4 m).

Genus DISCAMPHICERAS Spath, 1923 

Discamphiceras cf. D. toxophorum (Waehner)

Plate 1, figures 3, 4, 8-10

This species is represented by 12 specimens, of which 

10 are crushed laterally. It is characterized by moderately involute coiling; an umbilicus that is about two-fifths 

as wide as the shell diameter; a high whorl section; a 

narrow, fairly sharp venter, and by moderately spaced 

ribs that trend radially, or incline slightly forward on the 

flanks, and that arch forward on the ventral area of 

smaller specimens. These ribs broaden and weaken ventrally and are faint or absent on venters of medium to 

large specimens. On the largest specimen the adapical 

half bears widely spaced ribs that fade out ventrally, 

whereas the adoral half is completely smooth. The 

suture line is not preserved.

This species closely resembles D. toxophorum 

Waehner (1884, p. 109, pi. 24, figs. 5a,b to 7a-c) in most 

respects but has somewhat sparser ribbing. The small 

specimens differ from comparable specimens of D. kammerkahrense (Gumbel) (Waehner, 1884, p. 113, pi. 24, 

figs. 3a-c, 4a-d) and from D. calcimontanum (Waehner) 

(1884, p. 112, pi. 24, figs, la-c, 2a,b) by having a wider 

umbilicus and sharper, sparser ribbing. The ribbing on 

the outer whorl of the largest Alaskan specimens is 

somewhat similar to that on the largest specimens of D. 

kammerkahrense (Gumbel) (Waehner, 1884, pi. 25, figs, 

la-c) and of D. calcimontanum (Waehner) (1884, pi. 24, 

figs. la,b).

Assignment of these Alaskan specimens to Discamphiceras rather than Waehneroceras is favored by their 

moderately involute coiling, by their ribs fading on the 

venter of small specimens, and by their adult outer 

whorl being fairly smooth.

Figured specimens.-USNM 247958-247961.

Occurrences.— Unnamed beds on peninsula between 

Puale Bay and Alinchak Bay on Alaska Peninsula at 

USGS Mesozoic Iocs. 3110, 25694, M1738, and ROC loc. 

3002.

Discamphiceras sp.

Plate 1, figures 5-7

Seven laterally crushed molds differ from the Alaskan 

specimens herein compared with Discamphiceras tox-
30 EARLY JURASSIC AMMONITES FROM ALASKA

ophorum (Waehner) by having weaker and more closely 

spaced ribs. In that respect they resemble a small 

specimen of D. calcimontanum (Waehner) (1884, p. 112, 

pi. 24, figs. 2a, b.) Their ribs are much weaker and do not 

extend as far ventrally as on the type specimens of D. 

toxophorum (Waehner) (1884, p. 109, pi. 24, figs. 5a-c to 

7a-c).

Figured specimens.—USNM 247962.

Occurrence.—Upper member of the McCarthy Formation in the Wrangell Mountains at USGS Mesozoic loc. 

29890.

Genus LAQUEOCERAS Lange, 1925

Laqueoceras cf. L. sublaqueus (Waehner)

Plate 3, figure 13

This species is represented by one laterally crushed 

specimen that includes a large internal mold and a small, 

shell-bearing fragment. The specimen is highly evolute, 

consists of many whorls, and bears fine radial, rather 

closely spaced ribs. These ribs are fairly distinct on the 

inner whorls at diameters as large as 75 mm but 

gradually become faint at greater diameters and are 

barely evident on the outermost whorl. The venter is 

poorly exposed but apparently does not bear a keel.

The specimen is similar to L. sublaqueus (Waehner) 

(1886, p. 142, pi. 15, fig. 2; pi. 16, fig. 10; pi. 30, fig. 4; 

Donovan, 1952, p. 641, 642) in size and in the strength, 

closeness, and persistence of its ribbing.

Figured specimen.-USNM 247963

Occurrence.—Unnamed Lower Jurassic beds on south 

side of Alinchak Bay on Alaska Peninsula at ROC loc. 

3002.

Genus WAEHNEROCERAS Hyatt, 1889

Waehneroceras cf. W. tenerum (Neumayr)

Plate 2, figures 1-6

cf. Aegoceras tenerum Neumayr, 1879, K. K. Geol. Reichsanst., Abh.

v. 7, p. 31, pi. 3, figs. 4, 5. 

cf. Waehneroceras tenerum (Neumayr). Arkell and others, 1957,

Treatise on invertebrate paleontology, Part L, Mollusca 4, p. L235,

fig. 260-la,b.

This species is represented by 30 crushed molds. It has 

highly evolute coiling, a wide umbilicus, and an ovate 

whorl section. Its ribs are widely spaced, trend nearly 

radially on the flanks, become stronger ventrally, project forward and become much weaker on the margin of 

the venter, and are reduced in strength along the 

midline of the venter.

This species differs from the specimens herein compared with W. portlocki (Wright) by having a lower 

whorl section and much stronger and sparser ribbing. 

Its features are essentially the same as those of W. 

tenerum (Neumayr) (Arkell and others, 1957, p. L235, 

fig. 260-la,b). It is associated at four localities in Alaska 

with Waehneroceras cf. W. portlocki (Wright) and at 

three localities with Discamphiceras.

Figured specimens.—USNM 247964-247966.

Occurrences,—Unnamed beds on south side of Alinchak Bay on Alaska Peninsula at USGS Mesozoic Iocs. 

12075, 12394, 25694, 29268 and ROC loc. 3002; unnamed beds on east side of Puale Bay on Alaska Peninsula at USGS Mesozoic Iocs. 3109, 3110, 19803, 31370, 

and ROC loc. 1185.

Waehneroceras cf. W. portlocki (Wright)

Plate 2, figures 7, 10-15

cf. Aegoceras portlocki Wright, 1881, 1882, London, Palaeontographical Soc., 1. pi. 48, figs. 4, 5 (1881), p. 372 (1882). 

cf. Aegoceras extracostatum Waehner, 1882, Beitr. Pal. Geol. OsterUngarns v. Orient, v. 2, pt. 3, p. 74, pi. 14, fig. 1. 

cf. Macrogrammites grammicus Buckman, 1928, Type ammonites,

v. 7, pi. 761 a,b. 

cf. Schlotheimia (Waehneroceras) portlocki (Wright). Donovan, 1952,

Annals and Mag. Nat. History, ser. 12, v. 5, p. 646, pi. 22, figs. 5a,b. 

cf. Schlotheimia (Waehneroceras) portlocki (Wright). Dean, Donovan,

and Howarth, 1961, British Mus. (Nat. History) Bull., v. 4, no. 10,

p. 445, pi. 63, figs. 4a,b.

This species is represented by 33 internal and external 

molds, of which most are laterally crushed. These 

specimens have highly evolute coiling, a wide umbilicus, 

and a compressed whorl section. Their ribs trend nearly 

radially on the flanks, bend forward slightly on the ventral margin, are rather closely spaced on septate whorls 

and become more widely spaced on the incomplete body 

chamber. The venter is smooth along its midline as 

shown on several specimens. The suture line is not exposed.

In coiling and ribbing this species is essentially identical with the specimen of Waehneroceras portlocki 

(Wright) figured by Dean, Donovan, and Howarth (1961, 

pi. 63, figs. 4a,b) and probably represents the same 

species. None of the Alaska specimens, however, include 

the large outer whorl as figured by Wright (1881, pi. 48, 

figs. 4, 5) and Buckman (1928, pi. 761a,b). W. curviornatum (Waehner) (1882, p. 75, pi. 16, figs. 2-4) appears 

to have slightly coarser ribbing on its inner whorls and 

develops a smooth venter on its outer whorls.

Figured specimens.-USNM 247967-247972.

Occurrences,—Unnamed beds on south side of Alinchak Bay on Alaska Peninsula at USGS Mesozoic Iocs. 

12075, 12394, 25694, and 29268, and ROC loc. 3002; unnamed beds on east side of Puale Bay on Alaska Peninsula at Mesozoic loc. 3110, 29267 and 31370; unnamed 

beds in Richfield Oil Co.-Wide Bay test well No. 1, core 

no. 5 at depth of 2235 to 36 ft (681 m) on north side of 

Wide Bay, Alaska Peninsula.

Waehneroceras? sp.

Plate 2, figures 8, 9

Waehneroceras is possibly represented in the subsurface of northern Alaska by one small fragment of a 

whorl in which only the venter and upper part of the
SYSTEMATIC DESCRIPTIONS 31

flank are preserved. The specimen is characterized by 

simple ribs that project strongly forward on the venter 

and that are only slightly reduced in strength on the 

venter. These features are similar to those on immature 

specimens of Waehneroceras tenerum (Neumayr) (Arkell 

and others, 1957, p. L235, figs. la,b).

Figured specimen.- USNM 247973.

Occurrence.—Kingak Shale in South Barrow test well 

No. 12 at depth of 2181.5 ft. (665 m) in northern Alaska. 

This occurrence is 11 ft (3.3 m) below that of Psiloceras 

(Franziceras).

Family SCHLOTHEIMIIDAE Spath, 1923 

Genus SCHLOTHEIMIA Bayle, 1878

Schlotheimia sp.

Plate 2, figures 16, 17

One specimen is moderately evolute. Its whorl section 

is a little higher than it is wide. The umbilical width is 40 

percent of the diameter. Its ribs are simple, sharp, incline forward on the flanks, become a little stronger ventrally, arch forward on the venter, and are only slightly 

reduced in strength along the midline of the venter.

The ribbing on this specimen resembles that on the inner whorls of S. montana (Waehner) (1886, p. 165, pi. 

19, fig. 1; pi. 20, fig. 1) and of S. donar (Waehner) (1886, 

p. 173, pi. 21, figs. 2, 5).

Figured specimens.—USNM 247974.

Occurrence.—Unnamed beds in the Puale Bay area on 

Alaska Peninsula at USGS Mesozoic loc. 10820.

Genus BADOUXIA Guex and Taylor, 1976 

Badouxia canadensis (Frebold)

Plate 2, figures 18-21, 24-28

Psiloceras canadense Frebold, 1951, Canada Geol. Survey Bull. 18,

p. 3, pi. 1, figs. 1-6, pi. 2, fig. la-c; pi. 3, fig. 1. 

Psiloceras canadense Frebold, 1964a, Canada Geol. Survey Bull. 116,

p. 6, pi. 1, figs. l-5b. 

Psiloceras canadense Frebold, 1967b, Canada Geol. Survey Bull. 158,

p. 18, pi. 1, figs, lab, 2a,b, 3a-c. 

Badouxia canadensis (Frebold). Guex and Taylor, 1976, Eclogae

Geol. Helvetiae, v. 69, no. 2, p. 525.

This species is represented in Alaska by 10 fairly small 

specimens. Most of these (pi. 2, figs. 18, 24, 28) bear 

rather closely spaced ribbing comparable with that on 

certain specimens illustrated by Frebold (1951, pi. 1, fig. 

5a; 1967b, pi. 1, fig. 2a). A few specimens (pi. 2, figs. 20, 

26, 27) bear sparser ribbing, as does another specimen illustrated by Frebold (1951, pi. 1, figs. le,d; 1967b, pi. 1 

fig. 3a).

The species has ovate whorls that are higher than they 

are wide, embrace half or more of the preceding whorl, 

and are rounded ventrally. Its smaller whorls bear 

straight, fairly sharp, forwardly inclined ribs that extend across the lower two-thirds of the flanks and then 

either fade out rather abruptly or pass into very weak 

secondary ribs. Its larger whorls are marked only by

strong forwardly inclined ribs that fade out rather 

abruptly at the base of the upper third of the flanks. Its 

assignment to the genus Psiloceras is questioned 

because it is more involute and more strongly ribbed 

than is typical of that genus. Its ribbing is much 

stronger on the lower part of the flanks than in Arctoasteroceras jeletzkyi Frebold.

Hypotypes.-\JSNM 247975-247977 and 248062.

Occurrences.—Unnamed beds in the Healy (A-6) 

quadrangle in Alaska Range at USGS Mesozoic loc. 

31266; unnamed beds at Puale Bay in Alaska Peninsula 

at ROC loc. 1240, and USGS Mesozoic loc. 31372.

Badouxia columbiae (Frebold)

Plate 2, figures 22, 23

Psiloceras (Curviceras) columbiae Frebold, 1967b, Canada Geol.

Survey Bull. 158, p. 20, pi. 1, figs. lOa-c; pi. 2, figs. 1-5;

p. 3, figs. 2a-c. 

Schlotheimiat sp. indet. Frebold, 1951, p. 7, pi. 4, figs. 2-4.

One fragmentary ammonite bears simple ribs that incline forward on the flanks as do those on B. canadensis 

(Frebold), but that continue across the venter where 

they arch strongly forward as in B. columbiae (Frebold).

Figured specimen.-USNM 247978.

Occurrence.—Unnamed beds in the Healy (A-6) 

quadrangle, Alaska Range at USGS Mesozoic loc. 

31264.

Genus CHARMASSEICERAS Spath, 1924 

Charmasseiceras cf. C marmoreum (Oppel)

Plate 3, figures 1-3

This species is represented by three fragmentary 

molds of immature specimens. The best preserved internal mold shows that the species is fairly involute, that its 

ribbing changes during growth from fairly fine to 

moderately strong, that many ribs fork low on the 

flanks, and that all ribs curve forward on the upper parts 

of the flanks. One external mold bears similar forwardly 

curved ribs that terminate ventrally in shelly material 

whose smoothness suggest a ventral band.

These specimens are closely similar in involution and 

ribbing to the small specimen of Charmasseiceras marmoreum (Oppel) figured by Waehner (1886, pi. 22, figs. 

2-4) and by Frebold (1967b, pi. 3, figs. Ic and Id; pi. 4, 

figs. 2a-c).

Figured specimens.—USNM 247979.

Occurrence.—Kingak Shale in northern Alaska in the 

South Barrow test well No. 12 at depths of 2061.5 and 

2068 feet (628 and 630 m). Unnamed beds in Seldovia 

area in northern Alaska at USGS Mesozoic Iocs. 2979 

and 31637.

Charmasseiceras sp.

Plate 3, figures 4-10

Three small specimens are characterized by a subquadrate whorl section that is much higher than it is
32 EARLY JURASSIC AMMONITES FROM ALASKA

wide; by a flattened venter; by high, sharp, widely spaced ribs that incline forward strongly on the upper parts 

of the flanks; and by prominent forwardly inclined ventral swellings that on the largest specimen are joined 

across the venter by low weak chevron-shaped ribs.

These specimens differ from immature specimens of 

C. marmoreum (Oppel) (Waehner, 1886, pi. 22 figs. 2-6) 

by having slightly coarser ribs of which only a few fork 

low on the flanks. In whorl shape and ribbing, the 

specimens show more resemblance to some small 

specimens that were figured as C. charmassei (d'Orbigny) (1844, pi. 91, figs. 1,2). They also resemble some 

small specimens of C. posttaurinum (Waehner) (1886, 

pi. 23, figs. 17a-c) in ribbing but are much more compressed.

Figured specimens.—USNM 247980, 247981.

Occurrences.—Kingak Shale in northern Alaska in the 

South Barrow test well No. 12 at depth of 2,056 feet 

(627 m) and in the South Barrow test well No. 3 at depths of 2,412 and 2,419.5 feet (735 and 737 m).

Family ARIETITIDAE Hyatt, 1874

Subfamily ARIETITINAE Hyatt, 1874

Genus ARIETITES Waagen, 1869

Arietites cf. A. bucklandi (J. Sowerby)

Plate 4, figures 11-13

"Arietites" cf. "A." bucklandi (J. Sowerby). Imlay, 1955, U.S. Geol. 

Survey Prof. Paper 274-D, p. 87, pi. 10, figs. 7, 8.

The assignment of this species to Arietites was accepted by Arkell (1956, p. 530). No other specimen of the 

genus has yet been found in Alaska.

Figured specimen.-USNM. 108778.

Occurrence.—Kingak Shale in northern Alaska in the 

Avak test well No. 1 at depth of 1836 ft (560 m).

Genus CORONICERAS Hyatt, 1867 

Coroniceras sp. A

Plate 4, figures 1-5

This species, represented only by fragmentary 

material, is similar in appearance to Coroniceras 

multicostatum (J. de C. Sowerby) (1824, v. 5, p. 75, pi. 

454; Reynes, 1879, pi. 25, figs. 1-2; Guerin-Franiatte, 

1966, p. 141, pis. 29-32). The specimens from Alaska are 

fairly evolute. Their whorls are higher than they are 

wide. Their ribs are fairly strong, radial on the flanks, 

bend forward on the ventral margin, and bear ventrolateral tubercles. Their keel is fairly strong and on internal molds is bordered by shallow furrows.

Figured specimen.—USNM 247982.

Occurrence.—Unnamed Lower Jurassic beds in 

Talkeetna (C-6) quadrangle, central part of the Alaska 

Range at USGS Mesozoic loc. 30908.

Coroniceras sp. B

Plate 4, figures 6-10

This species is represented by 12 poorly preserved internal and external molds. Its appearance is similar to 

that of the specimens herein described as Coroniceras 

sp. A, but differs by having ribs curving forward much 

more strongly on the upper part of its flanks. In that 

respect it shows more resemblance to C. haueri 

(Waehner) (1886, p. 38, (127), pi. 19, fig. la,b; pi. 20, fig. 

2a,b). Its ribbing also resembles some species of 

Caenesites (J. de C. Sowerby, 1824, pi. 452, fig. 1; 

Wright, 1879, pi. 12, fig. 1; Arkell, 1956, pi. 31, fig. 1, 

Dean and others, 1961, pi. 66, figs. 1,2; GuerinFraniatte, 1966, pis. 204, 208). It differs from that 

genus, however, in that its keel is bordered by very weak 

instead of deep furrows.

Figured specimen.-USNM 247983, 247984.

Occurrences.—Kingak Shale in northern Alaska in the 

South Barrow test well No. 12 at depth of 1987.4 to 

1987.6 ft (606 m).

Coroniceras sp. C

Plate 4, figure 14

Three small fragmentary molds of ammonites from 

the subsurface of northern Alaska possibly represent 

the inner whorls of the species described herein as Coroniceras sp. A. They appear, however, to have slightly 

sparser ribs that bear stronger tubercles on the ventrolateral margin. The keel is fairly low and is not 

bordered by furrows.

Figured specimens.—USNM 247985.

Occurrence.—Kingak Shale in northern Alaska in the 

South Barrow test well No. 3 at depth of 2470 ft (753 m).

Subgenus PARACORONICERAS Spath, 1922 

Coroniceras (Paracoroniceras) sp.

Plate 4, figures 23-25

One species, represented by a crushed fragment of an 

outer whorl and by one internal mold, bears prominent 

widely spaced ribs that trend radially on the flanks and 

curve forward on the ventral margin. Its keel is fairly 

high and is not bordered by furrows. Its whorl section is 

considerably higher than wide.

This specimen resembles the adoral end of the outermost preserved whorl of the coarsely ribbed holotype of 

Coroniceras (Paracoroniceras) charlesi Donovan (1955, 

p. 12, 28; Reynes, 1879, pi. 16, figs. 1, 2; GuerinFraniatte, 1966, p. 153, pi. 38).

Figured specimen.—USNM 247986.

Occurrence.—Unnamed beds in the Seldovia area on 

Kenai Peninsula at USGS Mesozoic Iocs. 31128 and 

31650.
SYSTEMATIC DESCRIPTIONS 33

Genus ARNIOCERAS Hyatt, 1867

Arnioceras cf. A. densicosta (Quenstedt)

Plate 5, figures 9-11, 16-24

This species is represented by 38 specimens, of which 

most are molds; but shelly material is preserved on some 

small specimens obtained from a well core in northern 

Alaska. It has highly evolute coiling. Its ribs are sharp, 

fairly closely spaced, trend radially on the flanks, bend 

forward on the margins of the venter, and then fade out 

on the venter. Its innermost whorls are smooth to a 

diameter of 15 to 20 mm. Its venter bears a keel that is 

bordered by distinct furrows on the internal mold and by 

weak furrows where shelly material is preserved. These 

features are essentially identical with those on the lectotype of Arnioceras densicosta (Quenstedt) (1858, pi. 7, 

fig. 7; 1884, p. 100, pi. 13, fig. 7; Guerin-Franiatte, 1966, 

pi. 142, figs. la,b) and on other comparable illustrated 

specimens (Guerin-Franiatte, 1966, p. 265, pi. 142, figs. 

2, 3; Reynes, 1879, pi. 14, figs. 5, 6).

The suture line is similar to that on A. densicosta 

Quenstedt (1884, pi. 13, fig. 7). The first lateral lobe is 

broad, bifid, and a little deeper than the ventral lobe. 

The first lateral saddle is bifid.

Figured specimens— USNM 247987-247989.

Occurrences.—Unnamed beds in the Puale Bay area on 

Alaska Peninsula at USGS Mesozoic loc. 21237, and 

ROC Iocs. 1282N, ROC 1282S, and ROC 1283A; unnamed beds in the Healy (A-6) quadrangle, Chulitna Valley 

area in the Alaska Range at USGS Mesozoic Iocs. 16229, 

31260, 31262, 31263, 31265. Upper member of McCarthy Formation in the Wrangell Mountains at USGS 

Mesozoic Iocs. 28535, 28538, and 30140.

Arnioceras sp. juv.

Plate 5, figures 5, 6, 12-15

Arnioceras is represented in northern Alaska by many 

small immature specimens obtained from a well core in 

the Point Barrow area. These specimens are nearly 

identical in coiling, whorl shape, and ornamentation 

with the inner whorls of the specimens herein described 

as A. cf. A. densicosta (Quenstedt). They differ by their 

innermost whorls, being smooth only to diameters of 8 

to 15 mm.

Figured specimens.—USNM. 247990.

Occurrence.—Kingak Shale in northern Alaska in the 

South Barrow test well No. 12 at depth of 2056 ft 

(626.7 m)

Genus PARACALOCERAS Spath, 1923 

Paracaloceras rursicostatum Frebold

Plate 6, figures 1-11

Paracaloceras rursicostatum Frebold, 1967b, Canada Geol. Survey 

Bull. 158, p. 26, pi. 7, figs, la-c, 2a-c; pi. 9, fig. 1.

Ten laterally crushed internal molds are characterized

by highly evolute coiling and by strong, rather widely 

spaced ribs that curve adapically on most flanks, curve 

adorally and become stronger on the ventral margin, 

and then terminate abruptly. The keel on the mold is 

fairly low and is bounded laterally by two furrows that 

are bounded by ridges. The furrows and the lateral 

ridges are very weak on the small specimens but are 

strong on the larger specimens (pi. 6, figs. 1, 5, 11). On 

the least crushed specimen (pi. 6, figs. 7, 11), the whorl 

section is nearly as wide as it is high. During growth, the 

adapical arching of the ribs becomes more pronounced.

All the specimens from Alaska have sparser and 

somewhat coarser ribbing than those described as 

Paracaloceras cf. P. coregonense (Sowerby) by Frebold 

(1951, p. 7, pi. 5, figs. 1-6; pi. 6, fig. 1; 1967b, p. 24, pi. 7, 

figs. 3-7). Their ribbing is similar, however, to some 

specimens illustrated by Waehner (1888, pi. 21, figs. 

1-2; pi. 23, fig. 4) as Arietites coregonensis Sowerby. 

They differ mainly by having ribs bending adapically 

more strongly on their largest whorls, a feature 

characteristic of P. rursicostatum Frebold.

Hypotypes.-USNM 247991-247997 and 248070.

Occurrences.—Unnamed beds in the Puale Bay area on 

Alaska Peninsula at USGS Mesozoic Iocs. 10820, 12396, 

31372, and ROC loc. 1241; unnamed beds in the Seldovia 

area on Kenai Peninsula at Mesozoic loc. 2981; unnamed 

beds in the Healy (A-6) quadrangle in Alaska Range at 

Mesozoic loc. 31266.

Genus ARCTOASTEROCERAS Frebold, 1960 

Arctoasteroceras jeletzkyi Frebold

Plate 5, figures 1-4

Arctoasteroceras jeletzkyi Frebold, 1960, Canada Geol. Survey Bull.

59, p. 14, pi. 2, figs. 1-5; pi. 3, figs. 1-3. 

Arctoasteroceras jeletzkyi Frebold, 1964b, Canada Geol. Survey Bull.

63-4, p. 5, pi. 2, figs. 1, 2.

This species is represented in Alaska by two 

specimens, of which the larger closely resembles the 

holotype (Frebold, 1960, pi. 2, fig. la,b) and the smaller 

resembles a paratype (Frebold, 1960, pi. 3, fig. 3a,b). 

Resemblances include a moderately involute shell, an 

ovate whorl section, gently convex flanks, a low blunt 

keel, and moderately spaced ribs that incline forward on 

the lower two-thirds of the flanks and then bend forward 

and become faint on the upper third and on the venter. 

The only difference is the presence of faint sulci bordering the keel. The suture line is poorly preserved on the 

Alaska specimens.

Hypotypes.-USNM 247998, 247999.

Occurrences.—Unnamed beds in the Healy (A-6) 

quadrangle in Alaska Range at USGS Mesozoic loc. 

31261.
34 EARLY JURASSIC AMMONITES FROM ALASKA

Family ECHIOCERATIDAE Buckman, 1913 

Genus PALTECHIOCERAS Buckman, 1924

Paltechioceras cf. P. harbledownense (Crickmay)

Plate 4, figures, 15-22

cf. Melanhippites harbledoumensis Crickmay, 1928, California Univ. 

Pub. Dept. Geol. Sci. Bull., v. 18, no. 2, p. 61, pi. 3, pi. 4a-d.

Ten specimens represent a species characterized by 

highly evolute coiling, an elliptical whorl section that is 

much higher than it is wide, a single keel that is not 

bordered by furrows, and moderately spaced, simple, 

slightly flexuous ribs. On the smallest specimens up to a 

diameter of about 27 mm, the ribs trend radially or 

curve adapically on the flanks, become stronger ventrally, and terminate abruptly on the ventral margin (pi. 4, 

figs. 18-21). During further growth, as shown on the 

larger specimens, the ribs gradually become nearly 

radial, or incline slightly adorally on the flanks, and their 

ventral ends curve a little adorally.

These specimens closely resemble the paratypes of 

Melanhippites harbledownensis Crickmay (1928, pi. 4, 

figs, a-d) and likewise are associated with Entoliumt 

semiplicatum (Hyatt) (equals E. balteatum Crickmay, 

1928, pi. 4 figs. e-g). The ribbing on the Alaskan 

specimens is slightly sparser than on the holotype of 

Paltechioceras aplanatum Hyatt (Buckman, 1924, pi. 

482) but nearly identical with that on the same species as 

figured by Getty (1973, p. 20, pi. 4, fig. la,b). The ribbing 

is likewise similar to that on Vermiceras bavaricum mexicanum Erben (1956, p. 207, pi. 36, figs. 507), which is 

assigned to Paltechioceras by Hallam (1965, p. 1493).

Figured specimens.-USNM 248000-248002.

Occurrences.—Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic Iocs. 28661 and 28663; upper member of McCarthy Formation in the Wrangell 

Mountains at USGS Mesozoic Iocs. 30139 and 31174.

Subgenus ORTHECHIOCERAS Trueman and Williams, 1925

Paltechioceras (Orthechioceras?) sp.

Plate 3, figures 11, 12

One small specimen, consisting of five incomplete 

whorls, is characterized by highly evolute coiling, by a 

subquadrate whorl section that is slightly wider than 

high; by a carinate bisulcate venter whose sulci are fairly 

shallow; and by simple forwardly curved ribs that are 

rather closely spaced on the innermost whorls but 

become more widely spaced on the outermost whorl.

The specimen shows considerable resemblance to P. 

(0.) radiatum Trueman and Williams (1925, p. 724, pi. 2, 

fig. 9a,b; Getty, 1973, p. 23, pi. 5 figs. la,b, 2a,b), but its 

ribbing is denser on its four smallest whorls. It also 

shows some resemblance to the inner whorls of P. (P.) 

elicitum Buckman (1924, pi. 483) but differs by having 

shallower sulci and by ribs which become more widely 

spaced adorally.

The specimen is assigned to the subgenus Orthechioceras rather than the subgenus Paltechioceras 

because of its fairly shallow sulci and because its ribs 

become widely spaced during growth. Its poor preservation, however, does not warrant a positive subgeneric 

determination.

Figured specimen.-USNM 248003.

Occurrence.—Unnamed beds in the Healy (A-6) 

quadrangle in Alaska Range at USGS Mesozoic loc. 

31261.

Family EODEROCERATIDAE Spath, 1929

Subfamily XIPHEROCERATINAE Spath, 1925

Genus CRUCILOBICERAS Buckman, 1920

Crucilobiceras cf. C. crucilobatum Buckman

Plate 5, figures 7, 8

One laterally crushed, fairly large external mold 

represents a highly evolute, fairly large bituberculate 

ammonite that is similar is appearance to Crucilobiceras 

and Microderoceras. Its outer two whorls bear rather 

weak, fairly sparse radial ribs that become stronger ventrally. The tubercles in the outer row occur near the ventral margin, are fairly prominent, and are round to 

slightly elongate spirally. The tubercles in the inner row 

occur at about the top of the lower third of the flanks, 

are fairly weak, are elongate radially, and appear to be a 

little stronger on the outermost whorl than on the next 

smaller whorl. The smallest whorls are much corroded.

The same species is probably represented by one small 

crushed mold that differs from the large specimen mainly by having more pronounced ribs and tubercles.

These specimens are similar in appearance to C. 

crucilobatum Buckman (1920, pi. 178) except for having 

more closely spaced ribs. Their assignment to 

Crucilobiceras rather than Microderoceras is based on 

the weakness of the inner row of tubercles and the 

rather high ventral position of the outer row of 

tubercles.

In England C. crucilobatum Buckman occurs in the 

lower part of the Echioceras raricostatum zone 

(Buckman, 1920, v. 3, pi. 178).

Figured specimens.-USNM 248004, 248005.

Occurrence.—Upper member of McCarthy Formation 

in the Chitina Valley of Wrangell Mountains at USGS 

Mesozoic loc. 14472 and probably at Mesozoic loc. 14030.

Crucilobiceras cf. C. densinodulum Buckman

Plate 7, figures 4, 5

cf. Crucilobiceras densinodulum Buckman, 1923, Yorkshire type

ammonites, v. 5, pi. 442. 

cf. C. densinodulum Buckman. Dean, Donovan, and Howarth, 1961,

p. 459, pi. 67, fig. 5.

One worn specimen is characterized by highly evolute 

coiling; by a quadrate whorl section that is a little wider 

than high; and by very widely spaced flank ribs that incline slightly adorally, are swollen radially on the lower
SYSTEMATIC DESCRIPTIONS 35

part of the flanks, weaken near the middle of the flanks, 

and terminate ventrally in prominent spirally elongate 

tubercles. These tubercles are well preserved at only one 

place.

This specimen differs from C. densinodulum Buckman 

by having weaker ribs near the middle of its flanks. C. 

densinodum (Quenstedt) as figured by Wright (1880, pi. 

39, figs. 6, 7; 1882, pi. 50, figs. 11,12) has much stronger 

ribbing and a higher whorl section. The species C. densinodulum occurs in the lower part of the Echioceras 

raricostatum zone (Dean and others, 1961, p. 459).

Figured specimen. -USNM 248006

Occurrence.—Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic loc. 28661.

Crucilobiceras cf. C. muticum (d'Orbigny)

Plate 7, figures 6-10, 12-15

This species is represented by 17 laterally compressed 

specimens, of which 15 are from USGS Mesozoic loc. 

28661. It is characterized by highly evolute coiling; a 

subquadrate whorl section that is a little higher than 

wide; and ribs that are strong, straight, rather sparse, 

incline forward on the flanks, become stronger ventrally, and terminate in fairly prominent tubercles on the 

ventral margin. The venter is gently rounded, smooth 

on the inner whorls, but marked on some outer whorls 

by weak swellings that arch gently forward from the 

tubercles. Most of the specimens have rather widely 

spaced ribs, as in C. muticum (d' Orbigny) (1844, p. 274, 

pi. 80).

C. muticum (d'Orbigny) in Europe is recorded from 

the Uptonia jamesoni Zone at the base of the 

Pliensbachian and questionably from the top of the 

underlying Echioceras raricostatum Zone (Bremer, 

1965, p. 155; Mouterde and Ruget, 1970, p. 50; Geczy, 

1976, p. 57).

The specimens herein compared with C. muticum 

(d'Orbigny) and C. submuticum (Oppel) are associated 

with echioceratid ammonites and hence must be of latest 

Sinemurian Age.

Figured specimens.-USNM 248007.

Occurrences.—Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic Iocs. 28661, 28662, and 

28663.

Crucilobiceras cf. C. submuticum (Oppel)

Plate 7, figures 1-3

Six specimens differ from those herein compared with 

C. muticum (d'Orbigny) by having finer and more closely 

spaced ribs as in C. submuticum (Oppel) (Quenstedt, 

1885, pi. 33, figs. 1, 9,19, 23). As five of these specimens 

are associated with the specimens herein compared with 

C. muticum (d'Orbigny), they may all be variants of a 

single species.

C. submuticum (Oppel) in Europe is recorded from the 

Uptonia jamesoni zone at the base of the Pliensbachian 

(Arkell, 1956, pi. 128; Bremer, 1965, p. 156). Similar 

finely ribbed specimens from Hungary are recorded 

from the Tragophylloceras ibex Zone (Geczy, 1976, p. 

58).

Figured specimens.- 248008, 248009.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 6706 and 28661.

Crucilobiceras cf. C. pacificum Frebold

Plate 8, figures 10-12, 15-17

cf. Crucilobiceras pacificum Frebold, 1970, Canadian Jour. Earth 

Sci., v. 7, no. 2, p. 435-437, pi. 1, figs. 4-8; pi. 2, fig. 10.

One specimen, represented by external and internal 

molds, is nearly identical in whorl shape, ribbing, and 

tuberculation with the type specimens of Crucilobiceras 

pacificum Frebold. Its cross section is quadrate, slightly 

higher than wide, and is broadest at the ventrolateral 

border. Its venter is nearly flat and its flanks are slightly 

convex. Its ribs on the flanks are widely spaced, fairly 

strong, incline slightly forward, and terminate on the 

ventrolateral margin in nodes that are elongate spirally. 

Between successive strong ribs generally occur single 

weaker ribs, most of which fade out on the upper parts 

of the flanks. The surface of the venter is somewhat irregular but is not marked by ribs.

The identification of this specimen with Crucilobiceras 

pacificum Frebold is favored not only by these features 

but by the fact that it is likewise associated with fairly 

well preserved specimens of Tropidoceras actaeon (d'Orbigny), as in the Queen Charlotte Islands.

Figured specimens.—USNM 248010.

Occurrence.—Near top of upper member of the 

McCarthy Formation in the Wrangell Mountains at 

USGS Mesozoic loc. 28534.

Subfamily COELOCERATIDAE Haug, 1910 

Genus APODEROCERAS Buckman, 1921

Apoderoceras cf. A. subtriangulare (Young and Bird)

Plate 8, figures 14, 18-23

cf. Deroceras subtriangulare (Young and Bird). Buckman, 1913,

Yorkshire type ammonites, v. 2, pi. 71A, B. 

cf. Platypleuroceras1! sp. indet. Frebold, 1970, Canadian Jour. Earth

Sci., v. 7, no. 2, p. 439, pi. 1, fig. 3).

This species is represented by two specimens. It is 

characterized by evolute coiling; a wide, depressed 

whorl section that is widest near the venter; a venter 

that is slightly arched on the smallest preserved whorls, 

nearly flat on the largest whorls, and smooth or faintly 

striate; and straight simple ribs that begin low on the 

umbilical wall, incline slightly adorally on the flanks, and 

terminate in prominent nodes on the margin of the 

venter. The ribs exposed in the umbilicus of the innermost preserved whorls are sharp and fairly closely
36 EARLY JURASSIC AMMONITES FROM ALASKA

spaced, but at a diameter of about 25 mm they become 

much stronger and more widely spaced. The suture line 

is not preserved.

The largest specimen at a diameter of about 120 mm 

has a whorl height of about 30 mm, a whorl thickness of 

46 mm, and an umbilical width of 68 mm.

The largest preserved whorl of this species resembles 

that of the holotype of A. subtriangulare (Young and 

Bird) (Buckman, 1913, pi. 71A,B) from England but 

differs by having a flatter venter and more closely 

spaced ribs. The smallest whorls resemble those of 

Platypleurocerasl sp. indet. of Frebold (1970, pi. 1, fig. 

3) from the McConnell Creek area in western British 

Columbia, except possibly for an abrupt change in 

strength of ribbing.

Figured specimens.-USNM 248011, 248012.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 6697 and M6171.

Family OXYNOTICERATIDAE Hyatt, 1875 

Genus FANNINOCERAS McLearn, 1930

Fanninoceras kunae McLearn

Plate 7, figure 11

Four immature specimens resemble F. kunae 

McLearn (1930, p. 5, pi. 2, fig. 4; 1932, pi. 9, figs. 1-6; 

Frebold, 1964b, pi. 9, fig. 4) in having a fairly wide umbilicus, a narrowly rounded venter, and moderately 

strong ribs that project forward on the flanks and 

become very weak on the venter.

Hypotype.-USNM 248013.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 24107, 24108, and 

27586.

Fanninoceras cf. F. carlottense McLearn

Twelve specimens resemble Fanninoceras carlottense 

McLearn (1932, p. 76, pi. 8, figs. 9, 10) in having a tiny 

umbilicus, a sharp venter, very weak, widely spaced ribs 

on small and intermediate-sized whorls, and nearly 

smooth outer whorls.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 24108 and 29449.

Family POLYMORPHITIDAE Haug, 1887 

Genus UPTONIA Buckman, 1898

Uptonia cf. U. dayiceroides Mouterde

Plate 9, figures 1-4, 8, 12-16

cf. Uptonia dayiceroides Mouterde, 1951, Soc. Geol. Portugal Bol., 

v. 9, no. 3, p. 179, pi. 1, figs. 4-6.

Uptonia cf. U. dayiceroides Mouterde. Frebold, 1970, Canadian Journal Earth Sci., v. 7, no. 2, p. 438, pi. 1, figs. 9a,b,c.

Eighty laterally crushed molds from the Wrangell 

Mountains are identical in coiling and density of ribbing 

with a specimen from the Queen Charlotte Islands that 

Frebold (1970, p. 438, pi. 1, figs. 9a,b) compared with 

Uptonia dayiceroides Mouterde.

On the small and intermediate-sized specimens from 

Alaska, the flank ribs are gently flexuous, become 

stronger ventrally, bear tubercles on the ventral 

margin, and then curve adorally. On the largest 

available specimens the flank ribs differ by not bearing 

tubercles. None of the specimens shows the middle part 

of the venter. Several associated specimens (pi. 9, figs. 

2, 14) that have slightly coarser and sparser ribbing are 

herein interpreted as a variant.

Figured specimens.-USNM 248014, 248015.

Occurrences.—Upper member of McCarthy Formation 

in the Wrangell Mountains at USGS Mesozoic Iocs. 

28671-28673 and 28675.

Uptonia cf. U. jamesoni (J. de C. Sowerby)

Plate 9, figure 17

One laterally crushed ammonite from northern Alaska 

greatly resembles a specimen of Uptonia jamesoni (J. de 

C. Sowerby) from England (Wright, 1882, p. 352, pi. 51, 

figs. 1-3; Dean and others, 1961, pi. 68, figs. 3a,b) in its 

evolute coiling and in its ribbing. Its ribs are fairly 

strong, incline slightly forward on the flanks, incline 

strongly forward on the margins of the venter, become 

swollen ventrally, and become much stronger adorally. 

Sharp ventral tubercles are not evident. Most of the 

venter is not exposed.

Figured specimen.—USNM 248016.

Occurrence.—Unnamed shale in northern Alaska at 

USGS Mesozoic loc. 29774.

Uptonia? sp.

Plate 9, figures 9-11

Six small crushed ammonites from northern Alaska 

are nearly identical in coiling and ornamentation with 

the inner whorls of the fairly large ammonite described 

herein (pi. 9, fig. 17) as Uptonia cf. U. jamesoni (J. de C. 

Sowerby). The only difference consists of the presence of 

very small, sharp tubercles on some ribs at the ventral 

margin. Such close resemblances suggest that the small 

ammonites are probably immature forms of the same 

species as the large ammonite. Their assignment to Uptonia rather than Crucilobiceras is favored by the forward curvature of their ribs on the highest parts of the 

flanks.

Figured specimens.-USNM 248017.

Occurrences.—Unnamed shale in northern Alaska at 

USGS Mesozoic Iocs. 29775, 29281, and 29282.

Uptonia? sp. A

Plate 8, figure 13

One fragmentary internal mold of a fairly large whorl 

bears ribbing similar to that on large specimens of 

Crucilobiceras and Uptonia. Assignment to Uptonia instead of Crucilobiceras is favored by the forward cur-
SYSTEMATIC DESCRIPTIONS 37

vature of the ribs at the ventral margin and by the fact 

that the ribs are not distinctly tuberculate.

The specimen constitutes the only evidence for the 

presence of Lower Jurassic beds in the Yakutat district.

Figured specimen. -USNM 248018.

Occurrence.—Float from unnamed beds in the Yakutat 

D-4 quadrangle, southeastern Alaska, at USGS 

Mesozoic loc. 29773.

Uptonia? sp. B

Plate 9, figures 5-7

Two small specimens have a compressed, fairly 

evolute shell and fairly sharp, simple ribs that incline 

slightly adorally on the flanks, become stronger ventrally, form pronounced chevrons on the venter, and do not 

bear ventral tubercles.

These features suggest that the specimens are immature forms of Uptonia. Such an assignment is suggested by their association with a fairly large, typical 

specimen of Apoderoceras, which genus in Europe is 

characteristic of the lower part of the Uptonia jamesoni 

zone of earliest Pliensbachian Age (Dean and others, 

1961, p. 463).

Figured specimen.—248019.

Occurrence.— Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic loc. 6697.

Genus TROPIDOCERAS Hyatt, 1867 

Tropidoceras actaeon (d'Orbigny)

Plate 8, figures 1-9 

(For synonymy see Frebold, 1970, p. 440)

This species is represented in Alaska by four molds 

that are identical in appearance with the type specimens 

of T. actaevn (d'Orbigny) (1844, p. 232, pi. 61, figs. 1, 2) 

from France and with specimens of that species from 

the Queen Charlotte Islands illustrated by Frebold 

(1970, pi. 2, figs. 13a,b, 14a,b, 15a,b). The Alaskan 

specimens of the species have fairly evolute coiling. 

Their ribs are simple, moderately spaced, radial or 

slightly sigmoidal on the flanks, and they curve forward 

sharply on the ventral margins, where they fade out 

abruptly. On internal molds the venter ranges from narrowly rounded to fairly sharp and in places on some 

specimens bears a low blunt keel.

In Europe, this species is indicative of the lower to 

middle parts of the Tragophylloceras ibex zone of early 

Pliensbachian Age, according to Frebold (1970, p. 444, 

445).

Hypotypes.-USNM 248020-248023.

Occurrence.—Near top of upper member of the 

McCarthy Formation in Wrangell Mountains at USGS 

Mesozoic loc. 28534.

Family AMALTHEIDAE Hyatt, 1867 

Genus AMALTHEUS Montfort, 1808

Amaltheus margaritatus (Montfort)

Plate 10, figures 25, 26

(For synonymy and description see Howarth, 1958, London, Palaeontographical Soc., p. 13, 14 and Dagis, 1976, p. 7-9.)

This species was provisionally identified by Imlay in 

1955 (p. 87, pi. 10, fig. 4) based on a specimen from a test 

well in the Point Barrow area. The specific identification 

was subsequently confirmed by Howarth (1958, p. xxvi).

Hypotypes.-USNM 108768, 248024, 248025.

Occurrences.— Kingak Shale in northern Alaska in the 

South Barrow test well No. 3 at depths of 2,019 feet 

(639 m), 2,111 feet (634 m), and probably at 2,107 feet 

(641 m); in the Simpson test well No. 1 at depth of 5,677 

feet (1,730 m); and in unnamed beds in the DeLong 

Mountains at USGS Mesozoic loc. M2441.

Amaltheus stokesi (J. Sowerby)

Plate 10, figures 27, 28

(For most of the synonomy see Howarth, 1958, London, Palaeontographical Soc., pt. 1, p. 3-6.)

Amaltheus cf. A. nudus (Quenstedt). Imlay, 1955, USGS Prof. Paper

274-D, p. 87, pi. 10, fig. 5. 

Amaltheus stokesi (J. Sowerby). Howarth, 1958, London, Palaeontographical Soc. pt. 2, p. xxvi.

This species has strong, slightly sigmoidal, radialtrending ribs that curve forward rather strongly high on 

the flanks, where they bifurcate or trifurcate and then 

merge with chevrons on the venter. It is distinguished 

from Amaltheus margaritatus (Montfort), according to 

Howarth (1958, p. 6), by having ventral chevrons that 

are larger, fewer, less forwardly inclined, and distinctly 

connected by twos or threes with the flank ribs instead 

of being connected only by striae or separated by a 

smooth band.

The presence of A. stokesi in Alaska was first 

recognized by Howarth (1958, p. xxvi) on the basis of an 

illustration published by Imlay (1955, pi. 10, fig. 5). Furthermore, Howarth identified A. cf. A. stokesi on the 

basis of another illustration by Imlay (1955, pi. 10, fig. 

1). Other small specimens comparable with A. stokesi 

are illustrated on plate 10, figures 23 and 24.

Hypotypes.-USNM 108769, 248026, 248027.

Occurrences.—Kingak Shale in northern Alaska in the 

South Barrow test well No. 3 at depths of 2,193 and 

2,198 feet (668.4 and 670 m); from unnamed beds cropping out in northern Alaska at USGS Mesozoic loc. 

29165; and from Glenn Shale in east-central Alaska at 

Mesozoic loc. 29340.

Amaltheus cf. A. stokesi (J. Sowerby) occurs in the 

Kingak Shale in northern Alaska in the South Barrow 

test well No. 3 at the depth of 2,186 feet (666.3 m) and in 

outcrops at USGS Mesozoic loc. 30074. It occurs in the
38 EARLY JURASSIC AMMONITES FROM ALASKA

Talkeetna Formation in the Talkeetna Mountains in 

southern Alaska at USGS Mesozoic loc. 25941.

Subgenus PSEUDOAMALTHEUS Frebold, 1922 

A. (Pseudoamaltheus) engelhardti (d'Orbigny)

This taxon is represented in northern Alaska by a 

fragment from the South Barrow test well No. 3 at the 

depth of 2090 feet (637 m). It was assigned by Imlay 

(1955, p. 87, pi. 10, fig. 3) to Amaltheus sp. and by 

Howarth (1958, p. xxvi) to A. (Pseudoamaltheus) 

engelhardti (d'Orbigny). Howarth's identification was 

based on the presence of spiral ribs on the upper part of 

the flanks and on the keel, and on the lack of radial ribbing. He noted that the species and subgenus in Europe 

ranges from the upper part of the Amaltheus 

margaritatus zone to the end of the Pliensbachian, or 

Pleuroceras spinatum zone, and is a descendant of 

Amaltheus margaritatus (Howarth, 1958, p. 21-23).

Hypotype.-USNM 108766.

Family DACTYLIOCERATIDAE Hyatt, 1867 

Genus PRODACTYLIOCERAS Spath

Prodactylioceras italicum italicum (Fucini)

Plate 10, figure 3

Coeloceras lorioli Bettoni, 1900, Schweizer. palaeont. Gesell. Abh.,

v. 27, p. 76, pi. 7, fig. 12. 

Coeloceras italicum Meneghini in Fucini, 1900, Palaeontographica

Italica, v. 7, p. 72, pi. 13, fig. 4. 

Coeloceras italicum Meneghini in Fucini, 1905, Palaeontographica

Italica, v. 11, p. 115, pi. 6, figs. 11, 12, 14. 

Prodactylioceras italicum italicum (Fucini) in Fischer, 1971,

Geologica et Palaeontologica, v. 5, p. Ill, pi. 2, fig. 12. 

Prodactylioceras (Aveyroniceras) italicum (Meneghini in Fucini).

Geczy, 1976, Akad. Kiado, Budapest, p. 145, pi. 25, figs. 8-9; pi. 26,

figs. 1-4.

One laterally crushed specimen from Alaska is 

characterized by highly evolute coiling, by very fine, 

dense, simple, forwardly inclined ribs that become a little stronger ventrally, and by a few weak tubercles high 

on the flanks of the innermost whorls. Its appearance is 

identical with that of the finely ribbed subspecies, P. 

italicum italicum (Fucini) from Italy as described in 

Fischer (1971, p. 111). It has slightly finer ribbing than a 

specimen from eastern Oregon described as P. cf. P, 

italicum Meneghini (Imlay, 1968, p. C28, pi. 2, fig. 14). 

It differs from specimens in northern British Columbia 

and southern Yukon, described by Frebold (1964a, p. 10, 

pi. 3, figs. 2; 1970, p. 442, pi. 4, figs. 1, 2), by lacking 

forked ribs.

The association of the Alaskan specimen of Prodactylioceras with Uptonia shows that it occurs at or near 

the base of the Pliensbachian. Comparable finely ribbed 

specimens from southern Europe as listed herein are 

recorded from the zone of Tragophylloceras ibex near 

the base of the Pliensbachian (Fischer, 1971, p. 118, 

123).

Figured specimen, -USNM 248030.

Occurrence.—'Upper member of the McCarthy Formation in upper 100 ft (30.5 m), Wrangell Mountains, at 

USGS Mesozoic loc. 28671.

Prodactylioceras cf. P. italicum fucini R. Fischer

Plate 10, figures 4, 5

Three crushed molds are characterized by highly 

evolute coiling; by high, narrow, moderately spaced 

nearly radial ribs that become slightly stronger ventrally and bifurcate rarely, low on the flanks; and by lacking 

tubercles, at least on their outer whorls. Their rib spacing resembles that on P. italicum fucini R. Fischer 

(1971, p. Ill, pi. 2, figs. 8, 11) and is somewhat denser 

than in P. colubriforme (Bettoni) (1900, pi. 7, fig. 10; 

Pinna, 1966, pi. 10, fig. 6; Fischer, 1971, pi. 2, fig. 10) 

from southern Europe. The resemblance of these 

Alaskan specimens to P. italicum fucini Fischer plus 

their association with Uptonia suggests an age as early 

as the zone of Uptonia jamesoni (Fischer, 1971, p. 118, 

123) or as the lower part of the Tragophylloceras ibex 

zone.

Figured specimens.-USNM. 248031, 248032.

Occurrences.— Upper member of McCarthy Formation 

on Wrangell Mountains at USGS Mesozoic Iocs. 28540, 

28671, and 28673.

Genus DACTYLIOCERAS Hyatt, 1867 

Dactylioceras cf. D. commune (J. Sowerby)

Plate 11, figures 2, 3, 8

Four laterally compressed specimens from the 

Talkeetna Mountains are characterized by evolute coiling and by sharp, fairly prominent, moderately spaced 

primary ribs which are inclined slightly forward. Most of 

the primary ribs pass at about two thirds of the height of 

the flanks into pairs of slightly weaker secondary ribs 

that arch gently forward on the venter. Some primary 

ribs remain simple, and some secondary ribs arise freely 

on the margins of the venter. Tiny tubercles occur at the 

furcation points.

These specimens show some resemblance to Dactylioceras crassiusculosum (Simpson) (Buckman, 1912, 

pi. 62; Fischer, 1966, p. 29, pi. 1, figs. 11; pi. 3, fig. 11; 

Pinna, 1966, p. 94, pi. 5, fig. 3; Sapunov, 1963, p. 120, pi. 

2, fig. 3a,b), but they differ by having more closely spaced, weaker ribs that incline forward on the flanks instead of trending nearly radially. Compared with the lectotype of D. commune (Sowerby) (Buckman, 1927, pi. 

707; Arkell, 1956, pi. 33, figs. 4a,b), they have denser 

and weaker ribs on their outermost preserved whorl. 

They do not differ greatly in ribbing, however, from D. 

crassibundum (Simpson), which Howarth (1962a, p. 115, 

pi. 16, fig. 7a,b) considered to be a synonym of D. commune (Sowerby).
SYSTEMATIC DESCRIPTIONS 39

These specimens from the Talkeetna Mountains are 

nearly identical with most of the specimens from arctic 

Canada that were assigned to D. commune (Sowerby) by 

Frebold (1958, p. 2, pi. 1, figs. 1-7; 1960, p. 18, pi. 5, figs. 

4, 6) but have somewhat sparser ribbing than one 

specimen so assigned (Frebold, 1960, pi. 5, fig. 5).

Figured specimen.— USNM 248047.

Occurrence.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 24787 and 29198.

Subgenus ORTHODACTYLITES Buckman, 1926 

Dactylioceras (Orthodactylites) kanense McLearn

Plate 11, figures 4, 5, 9

Dactylioceras kanense McLearn, 1930, Royal Soc. Canada Trans., 3d.

ser., v. 24, sec. 4, p. 4, pi. 1, fig. 2 

Dactylioceras kanense McLearn, 1932, Royal Soc. Canada Trans., 3d

ser., v. 26, sec. 4, p. 59-62, pi. 3, fig. 5, pi. 4, figs. 1-7, 9 pi. 5,

figs. 6-9. 

Dactylioceras kanense McLearn. Frebold, 1964b, Canada Geol. Survey

Paper 63-4, pi. 7, figs. 1-4. 

IDactylioceras cf. D. kanense McLearn. Imlay, 1955, U.S. Geol.

Survey Prof. Paper 274-D, p. D88, pi. 10. fig. 14.

This species is represented by four molds that are 

nearly identical in appearance with the holotype. The 

species is characterized by an evolute, compressed shell, 

by a narrowly rounded venter, and by fine threadlike 

ribs that incline gently forward on the flanks and arch 

forward on the venter. On the inner whorls, furcation of 

the ribs is fairly common. On the largest whorl, most of 

the primary ribs are simple and many ribs arise freely on 

the upper parts of the flanks. The species shows considerable resemblance to D. attenuatus (Simpson) 

(Buckman, 1926, pi. 655) but has fewer forked ribs on its 

outer whorl.

Hypotype.-USNM. 248048.

Occurrence.—Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic loc. 29198. Possibly 

represented in northern Alaska in the South Barrow 

test well No. 3 at the depth of 2,016 feet (614.5 m) (Imlay, 1955, p. 82, 88).

Dactylioceras (Orthodactylites) cf. D. directum (Buckman)

Plate 11, figure 6

cf. Orthodactylites directum Buckman, 1926, Type ammonites, pi. 654. 

cf. Orthodactylites mitis Buckman, 1927, Type ammonites, pi. 738.

One specimen, whose outermost preserved whorl is 

crushed laterally, resembles the holotype specimen of D. 

(0.) directum Buckman in coiling and ribbing. It also 

resembles D. (0.) mitis Buckman, which Howarth (1973, 

p. 254, 255) considered to be a synonym of D. (0.) directum. As in those species, its ribs are fairly strong, nearly 

straight, rectiradiate, cross the venter nearly 

transversely and mostly bifurcate high on the flanks. 

Some ribs, however, remain simple.

Figured specimen.-USNM 248049.

Occurrence.—Kingak Shale in northern Alaska at 

USGS Mesozoic loc. 29163.

Genus CATACOELOCERAS Buckman, 1923 

Catacoeloceras? sp. juv.

Plate 12, figure 6

Coeloceras aff. C. mucronatum (d'Orbigny). Imlay, 1955, U.S. Geol.

Survey Prof. Paper 274-D, p. D88, pi. 12, figs. 12-14. 

Catacoeloceras sp. "aff. mucronatum (d'Orbigny)". Howarth, 1958,

London, Palaeontographical Soc. pt. 2, p. xxvi.

The assignment of this species to Catacoeloceras by 

Howarth was probably based on the generic definition 

published by Arkell and others (1957, p. L254). Later 

studies by Howarth (1962b, p. 407-410) showed, 

however, that most of the taxa listed in the treatise as 

synonyms of Catacoeloceras actually had different 

characteristics than the type species of Catacoeloceras, 

occurred in older beds just above the upper range of 

Amaltheus, and could appropriately be referred to 

Nodicoeloceras. He noted that Nodicoeloceras had small 

tubercles and looped ribs only on its innermost whorls. 

In contrast Catacoeloceras developed small ventrolateral 

tubercles on its inner and on some intermediate whorls 

but did not develop looped ribs.

The stratigraphic position of the Alaskan species 

above Amaltheus and below Dactylioceras (Imlay, 1955, 

p. 82; 1968, p. C21) favors an assignment to 

Nodicoeloceras rather than to Catacoeloceras. 

Nonetheless the presence of fairly prominent tubercles 

and the lack of looped ribs are indicative of 

Catacoeloceras such as C. confectum Buckman (1923, pi. 

413) and C. crassum (Young and Bird) (Buckman, 1918, 

pi. 119).

Figured specimen.— USNM 108758a-c.

Occurrence.—Kingak Shale in South Barrow test well 

No. 3 at depth of 2,063 ft (629 m).

Family HILDOCERATIDAE Hyatt, 1867

Subfamily ARIETICERATINAE Howarth, 1955

Genus ARIETICERAS Seguenza, 1885

Arieticeras cf. A. domarense (Meneghini)

Plate 10, figures 1, 2, 6-15, 22

This species is represented by 38 molds that match 

very well with specimens from eastern Oregon described previously under the same name (Imlay, 1968, p. C33, 

C34, pi. 4, figs. 9-12). Most of the molds also match certain specimens from northern British Columbia and 

southern Yukon that were assigned to Arieticeras cf. A. 

algovianum (Oppel) by Frebold (1964a, p. 13, pi. 3, fig. 

3a,b; pi. 5, figs. 2, 3). The species differs from the species 

herein called A. cf. A. algovianum (Oppel) by having a 

higher, more compressed whorl section and finer, more 

closely spaced ribs.

Figured specimens.-USNM. 248033-248037.
40 EARLY JURASSIC AMMONITES FROM ALASKA

Occurrences. -Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic Iocs. 24107, 27586 and 

29450. Lubbe Creek Formation in the Wrangell Mountains at Mesozoic loc. 28531. Upper member of the 

McCarthy Formation in the Wrangell Mountains at 

USGS Mesozoic loc. 28688.

Arieticeras cf. A. algovianum (Oppel)

Plate 10, figures 16-20

This species is represented by three fragments that 

resemble certain specimens from eastern Oregon (Imlay, 1968, p. C34, pi. 4, figs. 1-8) and from northwestern 

British Columbia (Frebold, 1964a, pi. 3, figs. 4a, b, 5a, b; 

pi. 4, fig. 2) that were compared, or identified with A. 

algovianum (Oppel). These specimens are characterized 

by highly evolute coiling, by a low keel that is bordered 

by shallow furrows, and by high, narrow, widely spaced 

ribs that trend radially or slightly adapically on the 

flanks.

Figured specimens.— USNM 248038.

Occurrence.—Upper member of McCarthy Formation, 

in the Wrangell Mountains at USGS Mesozoic loc. 

28688.

Arieticeras sp.

Plate 10, figure 21

On one small specimen the innermost whorls are 

smooth up to a diameter of about 6 mm. The next outer 

whorl, whose ventral part is not preserved, bears fairly 

low, moderately spaced ribs that curve slightly 

backward on the flanks. The outermost whorl bears fairly strong, widely spaced ribs that curve backward 

strongly on the lower and middle parts of the flanks, 

curve forward strongly on their upper parts, and then 

fade out on the ventral margin. The venter bears a low 

keel that is bordered by very shallow furrows.

This specimen differs from those in Oregon and 

British Columbia that have been compared or identified 

with A. algovianum (Oppel) (Imlay, 1968, p. C34, pi. 4, 

figs. 1-8; Frebold, 1964a, p. 13, pi. 3, figs. 4, 5; pi. 4, fig. 

2) by having sparser ribs that curve backward much 

more strongly on the flanks. Its rib plan shows more 

resemblance to that of Arieticeras retrorsicosta (Oppel) 

as in Quenstedt (1885, pi. 42, fig. 44) and A. cf. A. retrorsicosta (Oppel) in Monestier (1934, pi. 10, figs. 42, 43).

Figured specimen.-USNM 248039.

Occurrence.—Lubbe Creek Formation in the Wrangell 

Mountains at USGS Mesozoic loc. 28531.

Genus LEPTALEOCERAS Buckman, 1918

Leptaleoceras cf. L. pseudoradians (Reynes)

Plate 11, figures 12, 13

Ammonites pseudoradians Reynes, 1868, Essai de geologie et de 

paleontologie aveyronnaises: Paris (Baillere), p. 91, pi. 1, figs. 4a-c.

Arieticeras pseudoradians (Reynes). Monestier, 1934, Soc. Geol.

France Mem., new ser., v. 10, pt. 3 (Mem. 23), p. 63, pi. 8 figs. 66

and 68. 

Leptaleoceras pseudoradians (Reynes). Howarth, 1957, Geol. Soc.

London Quart. Jour., v. 113, p. 198, pi. 17, figs. 1, 2. 

Leptaleoceras pseudoradians (Reynes). Frebold, 1964a, Canada Geol.

Survey Bull. 116, p. 15, pi. 4, figs. 5-7, pi. 5, figs. 4, 5.

This species is represented by one fairly well preserved specimen that retains some shell material and is 

mostly septate. Its characteristics are identical with 

those of specimens from the southern Yukon and British 

Columbia as illustrated and described by Frebold.

Hypotype.-USNM 248040.

Occurrence.—Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic loc. 29450.

Genus FONTANELLICERAS Fucini, 1931 

Fontanelliceras cf. F. fontanellense (Gemmellaro)

Plate 11, figures 17-23

(For synonymy see Imlay, 1968, U.S. Geol. Survey Prof. Paper 593-C, 

p. C36.)

cf. Fontanelliceras fontanellense (Gemmellaro). Guex, 1973, Eclogae 

geol. Helvetiae, v. 66, p. 507, pi. 6, fig. 2.

The genus Fontanelliceras is represented by five 

specimens. The largest specimen (pi. 11, figs. 17,18, 23) 

has highly evolute coiling; a tricarinate bisulcate venter; 

and high, straight, rursiradiate ribs that become 

stronger ventrally and bend forward slightly before terminating on the ventral margin. The smaller specimens 

have been crushed laterally but resemble the larger in 

most respects. They differ by having ribs that are 

sharper, more widely spaced, and nearly radially arranged. The venter, which is well exposed on the largest 

specimen, bears a prominent keel bordered by furrows 

that in turn are bordered by weak ridges.

At a diameter of 59 mm, the largest specimen has a 

whorl height of 14 mm, a whorl thickness of 11 mm, and 

an umbilical width of 35 mm. Its suture line is not exposed.

Figured specimens.-USNM 248041-248043.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 25941, 27586, and 

29450.

Subfamily HARPOCERATINAE Neumayr, 1875 

Genus HARPOCERAS Waagen, 1869

Harpoceras cf. H. exaratum (Young and Bird)

Plate 11, figure 11

cf. Harpoceras exaratum (Young and Bird). Wright, 1882, London,

Palaeontographical Soc. pi. 62, figs. 1-3. 

Harpoceras cf. H. exaratum (Young and Bird). Imlay, 1955, U.S. Geol.

Survey Prof. Paper 274-D, p. 88, pi. 11, figs. 12, 13, 15. 

Harpoceras cf. H. exaratum (Young and Bird). Frebold and Little,

1962, Canada Geol. Survey Bull. 81, p. 17, 18, pi. 2, figs. 1-9, pi. 3,

fig. 5. 

Harpoceras cf. H. exaratum (Young and Bird). Frebold, 1964 a,

Canada Geol. Survey Bull. 116, p. 16, pi. 6, figs. 2-4 (not 1 and 5).
SYSTEMATIC DESCRIPTIONS 41

Harpoceras cf. H. exaratum (Young and Bird). Frebold, 1957, Canada 

Geol. Survey Mem. 287, p. 47, pi. 17, fig. 1; pi. 18, figs. 2, 3.

This species is represented by five fragmentary 

specimens from northern Alaska and one from the 

Talkeetna Mountains in southern Alaska. Their features 

match very well with those on specimens from western 

and Arctic Canada as described and illustrated by 

Frebold in the papers listed above.

Figured specimen.— USNM 248044.

Occurrences.— Kingak Shale in northern Alaska at 

USGS Mesozoic localities 22081, 29159, 29160, 29161, 

and 29776. Talkeetna Formation in Talkeetna Mountains at Mesozoic loc. 29198.

Genus PROTOGRAMMOCERAS Spath, 1913 

Protogrammoceras cf. P. paltum (Buckman)

Plate 12, figures 11, 12

cf. Paltarpites paltus Buckman, 1922, Type ammonites, v. 4, pi. 362a

and 1923, pi. 362b. 

Harpoceras cf.H. exaratum (Young and Bird). Frebold, 1964a, Canada

Geol. Survey Bull. 116, pi. 6, figs. 1, 5 (not 2-4). 

cf. Paltarpites paltus Buckman. Frebold, 1970, Canadian Jour. Earth

Sci., v. 7, no. 2, p. 443, pi. 4, figs. 5-7.

Three fragmentary specimens from Alaska bear ribbing similar to that on Protogrammoceras paltum 

(Buckman). They differ from P. argutum (Buckman) by 

having fewer ribs that are broader and flat topped. 

Nonetheless, as discussed by Frebold (1970, p. 443), the 

ribs during growth on some specimens of P. paltum vary 

considerably in strength from fine to coarse to fine, or 

even to striae. Consequently fragments of whorls bearing only striae, or only very fine ribs, cannot reliably be 

assigned to either species.

The assignment of both species to Protogrammoceras 

Spath rather than to Paltarpites Buckman, is based on 

examination of the type specimens by Howarth (1973, p. 

265).

Figured specimen.— USNM 248045.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 24108, 25941, and 

29449.

Protogrammoceras cf. P. argutum (Buckman)

Plate 11, figure 14

cf. Argutarpites argutus Buckman, 1923, Type ammonites, v. 4,

pi. 363. 

Paltarpites cf. P. argutus Buckman. Imlay, 1968, U.S. Geol. Survey

Prof. Paper 593-C, p. C37, pi. 5, figs. 20-22, 24, 25. 

cf. Paltarpites argutus (Buckman). Frebold, 1970, Canadian Jour.

Earth Sci., v. 7, no. 2, p. 444, pi. 4, figs. 8-10.

This species is represented by two fragments, that are 

characterized by very fine falcoid ribs and striae and by 

a rounded umbilical edge. It could be interpreted as a 

finely ribbed variant of P. paltum (Buckman), which 

species is associated with P. argutum (Buckman) in 

western Canada (Frebold, 1970, p. 444).

Figured specimen.—USNM 248046. 

Occurrences.—Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic Iocs. 24108 and 25941.

Genus ELEGANTICERAS Buckman, 1913 

Eleganticeras sp. juv.

Plate 11, figures 10, 15, 16

This species is represented by 12 small internal and 

external molds. They have a moderately compressed 

planulate form; a low vertical umbilical wall that rounds 

fairly abruptly into somewhat flattened flanks; a rather 

sharp keel on the venter; and an incomplete body 

chamber that occupies at least half a whorl. The innermost whorls are smooth. Weak, widely spaced ribs appear at a diameter of 7 to 9 mm and gradually become 

stronger during growth. The largest preserved septate 

whorl and the adapical end of the nonseptate whorl bear 

low falcoid ribs that are faint on the lower third of the 

flanks, become stronger ventrally, and extend almost to 

the keel. Such ribs are replaced rather abruptly on the 

adoral half of the largest preserved whorls by much 

weaker falcoid ribs and then by striae that are apparent 

only where some of the shell is preserved. The outermost whorl embraces about half of the preceding whorl.

In shape, coiling, and ribbing, this species greatly 

resembles the holotype of Elegantuliceras elegantulum 

(Young and Bird) (Buckman, 1914, pi. 93). It differs by 

being only half as large and by its umbilical wall being 

vertical instead of concave.

Figured specimen.-USNM 248050.

Occurrence.— Kingak Shale in northern Alaska at 

USGS Mesozoic loc. 29776.

Genus PSEUDOLIOCERAS Buckman, 1913 

Pseudolioceras cf. P. compactile (Simpson)

(See Imlay, 1955, U.S. Geol. Survey Prof. Paper 274-D, p. 89, pi. 12, 

figs. 17, 18, 21.)

Occurrence.—Kingak Shale at USGS Mesozoic loc. 

23772.

Pseudolioceras cf. P. lythense (Young and Bird)

(See Imlay, 1955, U.S. Geol. Survey Prof. Paper 274-D, p. D89, pi. 12,

fig. 20.)

Occurrence.—Kingak Shale at USGS Mesozoic loc. 

23772.

Pseudolioceras sp.

Plate 11, figure 1; Plate 12, figure 13

Two laterally compressed specimens from southern 

Alaska resemble P. moclintocki (Haughton) from arctic 

Canada and arctic Alaska (Frebold, 1964b, pi. 10, figs. 

4-8, 12; Imlay, 1976, pi. 1, figs. 1-5, 7.) They appear to 

have a smaller umbilicus and sparser, weaker ribbing, 

but their preservation is not sufficient for a positive 

specific determination.
42 EARLY JURASSIC AMMONITES FROM ALASKA

Figured specimens.-USNM 248051, 248052.

Occurrences.—Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic loc. 25317; Kialagvik Formation at Puale Bay on the Alaska Peninsula at USGS 

Mesozoic loc. 19804.

Subfamily GRAMMOCERATINAE Buckman, 1904 

Genus GRAMMOCERAS Hyatt, 1867

Grammoceras sp.

Plate 11, figure 7

One laterally crushed ammonite is characterized by 

evolute coiling by simple, strong, gently sigmoid ribs, 

and by a low keel as in Grammoceras. It has slightly 

coarser ribbing than does the ammonite from the 

southern Yukon described by Frebold (1964a, p. 17, pi. 

7, figs. 1, 2) as G. aff. G. fallaciosum (Bayle).

Figured specimen.—USNM 248053.

Occurrence.—Talkeetna Formation, upper part, in the 

Talkeetna Mountains at USGS Mesozoic loc. 25939.

Family HAMMATOCERATIDAE Buckman, 1887 

Genus PHYMATOCERAS Hyatt, 1867

Phymatoceras? sp.

Plate 12, figures 14, 16-19

The genus is possibly represented by three specimens. 

The smallest specimen (pi. 12, fig. 18) bears twinned ribs 

and a carinate venter similar to that on Phymatoceras 

binodata (Buckman) (1898, Supplement, p. XVI, pi. 1, 

figs. 11,12). In each twin the adapical rib is the stronger 

and is marked near the umbilical edge by a swelling. All 

ribs curve forward on the venter but are separated from 

the keel by a smooth area.

The next larger specimen is septate and bears alternating long and short ribs. The long ribs begin on the 

umbilical wall and are slightly swollen on the umbilical 

margin. The short ribs begin at or a little above the middle of the flanks. All ribs incline forward on the flanks 

and venter, become stronger ventrally, become swollen 

on the venter, and then terminate abruptly before 

reaching the keel.

The largest specimen is a nonseptate fragment that 

shows the venter and part of the flank of an adult whorl. 

It bears broad coarse ribs that are wider than the interspaces, that curve forward slightly on the flanks and 

more strongly on the venter, and that then terminate 

abruptly before reaching a rather low keel. The ventral 

aspect of this specimen is similar to that of P. tumefacta 

(Buckman) (1898, Supplement, p. XIX, pi. 1, figs. 7-10).

Figured specimens.-USNM 248054-248056.

Occurrences.—Talkeetna Formation, upper part, in 

the Talkeetna Mountains at USGS Mesozoic Iocs. 25317 

and 25342.

Genus BRODIEIA Buckman, 1898 

Brodieia cf. B. tenuicostata var. nodosa (Jaworski)

Plate 12, figure 8

cf. Hildoceras (Brodiceras) tenuicostatum var. nodosa Jaworski, 1926, 

Actas Acad. Nac. Cienc. Cordoba, v. 9, p. 245, pi. 4, fig. 8a,b.

One laterally crushed ammonite consists mostly of an 

incomplete body chamber that occupies at least threefourths of a whorl and embraces about two-thirds of the 

preceding whorl. The venter bears a single low keel. The 

ribs on the outer whorl are moderately strong, widely 

spaced, gently falcate, and terminate ventrally near the 

keel. The primary ribs begin low on the umbilical wall, 

are fairly strong near the umbilicus, weaken a little near 

the middle of the flanks, and are strongest on the 

margin of the venter. Some rib furcation occurs at 

various heights ranging from the umbilical margin to a 

little above the middle of the flanks. Other ribs arise 

freely near or above the middle of the flanks. All ribs are 

essentially of the same strength on the venter. The ribbing on the penultimate whorl as revealed in the umbilicus is also fairly strong.

This ammonite from Alaska bear ribbing almost identical with that on Brodieia tenuicostata var. nodosa 

(Jaworski) (1926, pi. 4, fig. 8a) from Argentina, but it 

differs by being a little more involute. In that respect it 

resembles the typical forms of B. tenuicostata (Jaworski) 

(1926, pi. 4, figs. 1-4, 6, 7) but differs by having slightly 

coarser and sparser ribbing. Overall the resemblances 

are remarkable.

Figured specimen.—USNM 248057.

Occurrence.—Talkeetna Formation in Talkeetna 

Mountains at USGS Mesozoic loc. 25940.

Genus HAUGIA Buckman, 1888 

Haugia cf. H. grandis Buckman

Plate 12, figures 4, 10, 15

cf. Haugia grandis Buckman, 1898, Supplement, p. XXVI, pi. s, 

fig. 11; 1888, pi. 23, figs. 14, 15; 1889, pi. 24, pi. 25, fig. 1

Ten specimens belong to a fairly involute species that 

has sharp, moderately spaced, flexuous ribs. The largest 

specimen is similar in size, involution, and ornamentation to a small specimen of H. grandis Buckman (1888, 

pi. 23, figs. 14, 15), but its tubercles are smaller and its 

ribs arch forward more strongly on its ventral margin. 

H. dumortieri Buckman (1888, pi. 23, figs. 16, 17) has 

fewer tubercles and ribs at a comparable size.

Figured specimen.-USNM 248058.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 24111 and 24114; 

Kialagvik Formation at Puale Bay on the Alaska Peninsula at Mesozoic loc. 19804.
REFERENCES CITED 43

Haugia cf. H. variabilis (d'Orbigny)

Plate 12, figures 1, 2, 5

cf. Ammonites variabilis d'Orbigny, 1845, Paleontologie francaise,

Terrains Jurassiques, v. 1, Cephalopods, p. 350, p. 113, figs. 1 and

2 only, 

cf. Harpoceras variabile (d'Orbigny). Wright, 1882, London,

Palaeontographical Soc., p. 455, pi. 67, figs. 5, 6 only, 

cf. Haugia aff. H. variabilis (d'Orbigny). Buckman, 1890, London,

Palaeontographical Soc., p. 146, pi. 25, fig. 2.

This species is represented by nine crushed molds. It 

has fairly evolute coiling. The ornamentation on its inner whorls consists of umbilical tubercles, of sharp, 

nearly radially trending ribs that arise mostly by two's 

and three's from the tubercles, and of a few ribs that 

arise freely between the tubercles. During subsequent 

growth, both tubercles and ribs gradually become 

stronger and more widely spaced. The ribs become gently flexuous on the flanks, arch forward slightly on the 

venter, and arise mainly in pairs from prominent conical 

tubercles. The characteristics of the adult body chamber 

are unknown.

The Alaskan species may be within the range of variation of H. variabilis (d'Orbigny), but it appears to be 

more evolute and to develop sparser ribbing. In these 

respects it shows more resemblance to H. aff. H. 

japonica (Neumayr) as illustrated by Matsumoto and 

Ono (1947, pi. 2, figs. 5). It has much coarser ornamentation than the holotype of H. japonica (Neumayr) 

(Kobayashi, 1935, pi. 12, figs. 3, 4).

Figured specimens.—USNM 248059.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic Iocs. 25318 and 27508.

Haugia cf. H. compressa Buckman

Plate 12, figures 3, 7, 9

cf. Haugia compressa Buckman, 1898, London, Palaeontographical 

Soc., Supplement, p. XXVII, pi. 2, figs. 8-10.

Nine molds represent a fairly involute and densely ribbed species. The largest specimen at a diameter of 66 

mm bears about 21 umbilical tubercles and about 65 

gently flexuous ribs that arise in two's and three's from 

the tubercles. Many ribs arise freely along the zone of 

tuberculation.

This species closely resembles H. compressa Buckman 

in involution and in density of ribibng but at a comparable size has slightly finer ribbing and smaller 

tubercles than the holotype.

Figured specimens.-USNM 248060, 248061.

Occurrences.—Talkeetna Formation in the Talkeetna 

Mountains at USGS Mesozoic loc. 24114; basal part of 

Kialagvik Formation at Puale Bay on Alaska Peninsula 

at Mesozoic loc. 19804.

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(1884); p. 481-503, pi. 88 (1886).

INDEX

actaeon, Tropidoeeras ______________ 18, 20, 35, 37; pi. 8

Aegasteroceras _____________________________ 2,3

simile __________________________________ 3

Aegoceras extracostatum ______________________ 30

portlocki _______________________________ 30

tenerum ________________________________ 30

Aichilik River ____________________ 5 

Alaska Peninsula _________________ 12, 28 

Alaska Range ______________10,12, 31, 33, 34 

algovianum, Arieticeras ______________20, 39, 40; pi. 10

Alinchak Bay ______________11, 12, 28, 29, 30 

Alsatites liasicus zone ________________________ 12

Amaltheidae ____________________ 4, 37 

Amaltheus ____________________________17,18, 37,39

margaritatus ____________________17,19, 37; pi. 10

zone _____________________ 38 

nudus __________________________________ 37

stokesi _________________7, 17, 18, 19, 21, 37; pi. 10

sp __________________________________17, 19, 38

(Pseudoamaltheus) _______________________ 2

engelhardti _________________________ 17, 3S

Ammonite zones:

Hettangian ___________________ 11 

Pliensbachian _________________ 17 

Sinemurian ___________________ 12 

Toarcian _____________________ 18 

Ammonites pseudoradians ____________________ 40

variabilis _______________________________ 43

Anatuvuk River ___________________ 17 

angulata, Schlotheimia _______________________ 12

aplanatum, Paltechioceras ____________________ 34

Apoderoceras _____________________________2, 35, 37

subtriangulare ___________________18, 21, 35; pi. 8

Arctic Coastal Plain ________________ 12,18 

Arctoasteroceras ________________________2, 3, 16, 33

jeletzkyi ____________________3, 16, 22, 31, 33; pi. 5

Argutarpites argutus ________________________ 41

argutum, Protogrammoceras __________18, 21, 41; pi. 11

argutus, Argutarpites ________________________ 41

argutus, Paltarpites _________________________ 41

Arieticeras ______________________2, 18, 39 

algovianum _____________________20, 39, 40; pi. 10

domarense ___________________18, 20, 21,39; pi. 10

pseudoradians ___________________________ 40

retrorsicosta ____________________________ 40

sp ______________________20, 40; pi. 10 

Arieticeratinae ___________________ 39 

Arietites ___________________________________ 2

bucklandi _____________________12, 13,17,32; pi. 4

zone _____________________ 13 

Arietitid genus undetermined ___________ 20, 22 

Arietitidae _____________________ 2, 4 

Arnwceras ____________________________2,13, 15, 33

densicosta ____________________15, 20, 22, S3; pi. 5

semieostatum ___________________________ 12, 15

sp _____________________17, 33; pi. 5 

Asteroceras obtusum _________________________ 3

obusum Zone _________________ 12,15 

attenuatus, Dactylioceras _____________________ 39

(Aveyroniceras) italicum, Prodactylioceras ___ 38

B

Badouxia __________________________________ 2,15

canadensis __________________________22, 3J; pi. 2

columbiae ___________________________22,3J; pi. 2

Bajocian _____________________7, 10, 11

[Italic page numbers indicate descriptions and major references]

balteatum, Entolium ________________________ 17, 34

bavaricum mexicanum, Vermiceras _____________ 34

binodata, Pkymatoceras ______________________ 42

(Brodiceras) tenuicostatum nodosa, Hildoceras ___ 42 

Brodieia _________________________________2, 18, 42

tenuicostata ____________________________ 21, 42

nodosa ____________________________42; pi. 12

bucklandi, Arietites ________________12,13, 17, 32; pi. 4

Caenisites __________________________________ 32

turneri zone ___________________ 12 

caZciTOonicwwTO, Discamphiceras ______________ 29, 30

(Caloceras), Psiloceras _______________________ 29

canadense, Psiloceras _______________________ 15, 31

canadensis, Badouxia ____________________22, 3i; pi. 2

Cape Simpson area _________________ 12 

carlottense, Fanninoceras ____________________ 21, 36

Catacoeloceras _____________________________ 2, 39

confectum _______________________________ 39

crassum ________________________________ 39

sp _____________________17, 39; pi. 12 

charlesi, Coroniceras (Paracoroniceras) _________ 32

Charmasseiceras __________________________2, 13, 15

charmassei _____________________________ 32

marmoreum _____________________17, 22, 3J; pi. 3

posttaurinum ___________________________ 32

sp _____________________17, 31; pi. 3 

charmassei, Charmasseiceras__________________ 32

Chitina Valley ___________________ 34 

Chulitna River ___________________ 12 

Chulitna River area ________________ 10,16 

Chulitna Valley ___________________ 2, 33 

Coeloceras italicum __________________________ 38

lorwli __________________________________ 38

mucronatum ____________________________ 39

Coeloceratidae ___________________ 35 

Coleen quadrangle _________________ 29 

colubriforme, Prodaetylioceras ________________ 38

columbiae, Badouxia ________________________31; pi. 2

columbiae, Psiloceras (Curviceras) ______________ 31

commune, Dactylioceras _________________21, 38; pi. 11

compactHe, Pseudolioceras _________________18, 19, 41

compressa, Haugia __________________21, 22, 43; pi. 12

confectum, Catacoeloceras _____________________ 39

coregonense, Paracaloceras ____________________ 33

Coroniceras haueri __________________________ 32

multicostatum ___________________________ 32

sp _________________________ 20, 22 

sp. A _______________________________22, 32; pi. 4

sp. B ____________________17, 32; pi. 4 

sp. C ___________________13,17, 32; pi. 4 

(Paracoroniceras) _______________________ 2, 15

charlesi _____________________________ 32

sp _____________________22, 32; pi. 4 

crassibundum, Dactylioceras __________________ 38

crassiusculosum, Dactylioceras ________________ 38

crassum, Catacoeloceras ______________________ 39

crucilobatum, Crucilobiceras ___________17, 20, 34; pi. 5

Cntciiofeiceros ________________2,15,17,34,36 

crucilobatum _____________________17, 20, 34; pi. 5

densinodulum _______________________21, 34; pi. 7

densinodum _____________________________ 35

muticum ___________________________21, 35; pi. 7

pacificum ________________________18, 20,35; pi. 8

submuticum _________________________21,35; pi. 7

sp __________________________ 21 

(Curviceras) columbiae, Psiloceras ______________ 31

curviornatum, Waehneroceras. 

D

30

attenuatus _____ 

commune ____. 

crassibundum __ 

crassiusculosum 

kanense _______

(Orthodactylites) _________________

.____2, 18, 38, 39 

______ 39 

__21, 38; pi. 11 

._____ 38 

._____ 38 

._____ 39 

17 

._ 2,39

directum _______________________19, 39; pi. 11

kananse _____________________17, 21,39; pi. 11

Dactylioceratidae _________________ 4, 38 

dayiceroides, Uptonia _________________18, 20,36; pi. 9

DeLong Mountains ________________5,18,37 

densicosta, Arnioceras _____________15, 20, 22, 33; pi. 5

densinodulum, Crucilobiceras _____________21, 34', pi. 7

densinodum, Crucilobiceras ___________________ 35

Deroceras subtriangulare _____________________ 35

directum, Dactylioceras (Orthodactylites) ___19,39; pi. 11 

Discamphiceras ___________________________2, 12, 29

calcimontanum _________________________ 29, 30

kammerkahrense _________________________ 29

toxophorum _________________________22, 29; pi. 1

sp _______________________20, 29; pi. 1 

domarense, Arieticeras ____________18, 20, 21,39; pi. 10

donar, Schlotheimia _________________________ 31

dumortieri, Haugia __________________________ 42

E

Echioceras _________________________________ 34

raricostatum ____________________4, 12, 15, 34, 35

Echioceratidae ___________________ 4 

Eleganticeras _______________________________ 41

sp _____________________19, 41; pi. 11 

Elegantuliceras _____________________________ 2

elegantulum _____________________________ 41

elegantulum, Elegantuliceras __________________ 41

elicitum, Paltechioceras (Paltechioceras) _________ 34

engelhardti, Amaltheus (Pseudoamaltheus) ______ 17, 38

Entolium balteatum _________________________ 17, 34

semiplicatum _________________________16,17, 34

Eoderoceratidae __________________ 2, 34 

Etivluk River ____________________ 17 

exaratum, Harpoceras ____________18, 19, 21, 40; pi. 11

extracostatum, Aegoceras _____________________ 30

fallaciosum, Grammoceras ____________________ 42

Fanninoceras ______________________________ 2, 36

carlottense _____________________________ 21, 36

kunae ______________________________21,36; pi. 7

fontanettense, Fontanelliceras _________18, 21,40; pi. 11

Fontanelliceras ___________________________2, 18, 40

fontanellense ____________________18, 21, 40; pi. 11

(Franziceras), Psiloceras _______________2, 7,12, 29, 31

ruidum, Psiloceras _____________12,19, 22, 29; pi. 1

sp., Psiloceras ____________________17,19, 29; pi. 1

jucini, Prodactylioceras italicum __________20,3S; pi. 10

G

Glenn Shale ____________________6, 29, 37 

grammicus, Macrogrammitf-s __________________ 30

47
48 INDEX

Grammoceras _____________________________2. 18, 42

faUaciosum _____________________________ 42

sp _____________________21, 42; pi. 11 

Grammoceratinae _________________ 42 

grandis, Haugia _____________________21,22, 42; pi. 12

H

Hammatoceratidae _________________ 2, 42 

harbledownense, Paltechioceras ___ 15, 17, 20, 21, 34; pi. 4 

harbledoumensis, Melanhippites ________________ 34

Harpoceras _______________________________2, 18, 40

exaratum ____________________18, 19, 21,40; pi. 11

variabile _______________________________ 43

Harpoceratinae ___________________ 40 

haueri, Coroniceras __________________________ 32

ffaMjrm______________________2, 11, 18, 42 

compressa ______________________21, 22, 43; pi. 12

dumortieri ______________________________ 42

jraradis _________________21, 22, 42; pi. 12 

japonica ______________________ 43 

variabilis __________________________21, 43; pi. 12

Zone ______________________ 18

sp __________________________ 21

Healy (A-6) quadrangle ___________10, 31, 33, 34

Hettangian _________________7, 11, 15, 16, 28

ammonites _____________________ 11

Hildoceras (Brodiceras) tenuicostatum nodosa ____ 42

Hildoceratidae ___________________2, 4, 39 

Howard Pass quadrangle _____________ 17

I

ibex Zone, Tragophylloceras _____________18, 35, 37, 38

Ignek Creek _____________________ 18 

Ipnavik River ___________________5, 16, 17 

italicum, Coeloceras _________________________ 38

Prodactylioceras ________________________ 18, 38

Prodactylioceras italicum ____________20, 38; pi. 10

Prodactylioceras (Aveyroniceras) ___________ 38

fucini, Prodactylioeeras ______________20, 38; pi. 10

italicum, Prodactylioceras ________20, 38; pi. 10 

Itkillik River _____________________ 5

jamesoni, Uptonia ____________________16, 19, 36; pi. 9

japonica, Haugia ____________________________ 43

jeletzkyi, Arctoasteroceras _____3, 16, 22, 31, 33; pi. 5

K

kammerkahrense, Discamphiceras ______________ 29

kanense, Dactylioceras _______________________ 39

Dactylioceras (Orthodactylites) _____ 17, 21, 39; pi. 11

Kavik River _____________________ 5, 16 

Kenai ________________________ 33 

Kenai Peninsula ______________10,12, 29, 32 

Kialagvik Formation _______________11, 42, 43 

Kingak Shale, _________5, 29, 31, 32, 33, 37, 39, 41 

kunae, Fanninoceras ______________21, 36; pi. 7

Laqueoceras ______________________________2, 12, 30

sublaqueus __________________________22, 30; pi. 3

Leptaleoceras _____________________________2, 18, 40;

pseudoradians ___________________ 18, 21, 40; pi. 11

liasicus, Zone Alsatites _______________________ 12

Lisburne Ridge ___________________ 17 

lorioli, Coeloceras ___________________________ 38

Lubbe Creek Formation _____________7,18,40 

lythense, Pseudolioceras____________________ 18, 19,41

Lytoceras __________________________________ 2

sp __________________________ 22

M

maclintocki, Pseudolioceras ___________________ 41

Macrogrammites grammicus __________________ 30

margaritatus, Amaltheus _____________17, 19, 37; pi. 10

marmoreum, Charmasseiceras __________ 17,22, 31; pi. 3

Matanuska River Valley _____________ 7, 9

McCarthy Formation _________7, 17, 18, 28, 30, 33

34, 35, 36, 37, 38, 40

Melanhippites harbledoumensis ________________ 34

mexicanum, Vermiceras bavaricum _____________ 34

Microderoceras _____________________________ 34

mitis, Orthodactylites ________________________ 39

montana, Schlotheimia _______________________ 31

mucronatum, Coeloceras ______________________ 39

multicostatum, Coroniceras _____________ 32 

Vermiceras _____________________________ 15

muticum, Crucilobiceras __________________21, 35; pi. 7

N

Nelchina _______________________ 9

Nelchina area ____________________ 7

Nodicoeloceras ______________________________ 39

nodosa, Brodieia tenuicostata _______________42; pi. 12

Hildoceras (Brodiceras) tenuicostatum _______ 42

North Fork of the American River _________ 17

nudus, Amaltheus ___________________________ 37

O

obtusum, Asteroceras ________________________ 3

Old Rampart ___________________6,11,17 

(Orthechioceras), Paltechioceras _______________2, 4, 34

radiatum, Paltechioceras __________________ 34

sp., Paltechioceras ______________________34; pi. 3

Orthodactylites directum ______________________ 19, 39

mitis __________________________________ 39

(Orthodactylites), Dactylioceras __________ 2

directum, Dactylioceras ______________19, 39; pi. 11

kanense, Dactylioceras ____________ 17, 21,39; pi. 11

Otapiria ___________________________________ 17

tailleuri ______________________________5, 16, 17

Oxynoticeras oxynotum ______________________ 3, 16

oxynotum Zone __________________ 12 

Oxynoticeratidae __________________ 36 

oxynotum, Oxynoticeras ______________________ 3, 16

pacificum, Crucilobiceras ______________18, 20,35; pl. 8

Pattarpites _________________________________ 41

argutus ________________________________ 41

paltus __________________________________ 41

Paltechioceras ____________________________ 16,17, 34

aplanatum ______________________________ 34

harbledownense _____________15,17, 20, 21,34; pl. 4

sp __________________________ 20 

(Orthechioceras) _________________________2, 4, 34

radiatum, ____________________________ 34

sp _____________________34; pl. 3 

(Paltechioceras) elicitum __________________ 34

(Paltechioceras) elicitum, Paltechioceras _________ 34

paltum, Protogrammoceras ___________ 18, 21, 41; pl. 12

paltus, Paltarpites ___________________________ 41

Paracaloceras ______________________________ 2, 15

coregonense _____________________________ 33

rursicostatum ____________________13, 22, 33; pl. 6

(Paracoroniceras) Coroniceras ________________ 2, 15

Parson Bay _____________________ 17 

Phymatoceras ______________________________ 2, 42

binodata ________________________________ 42

tumefacta _______________________________ 42

sp ______________________21, 42; pl. 12 

planorbis, Psiloceras __________________20, 22, 28; pl. 1

Platypleuroceras sp __________________ 35 

Pleuroceras spinatum Zone _____________ 38 

plicatum, Psiloceras (Psiloceras) __________ 29 

Pliensbachian __________________2, 4, 5, 7, 18 

ammonites _____________________ 17 

Point Barrow area _________________ 12, 37 

Polymorphitidae __________________2, 4, 36 

portlocki, Aegoceras _________________________ 30

Schlotheimia (Waehneroceras) ______________ 30

Waehneroceras ______________________22, 30; pl. 2

posttaurium, Charmasseiceras _________________ 32

Prodactylioceras ____________________________ 2, 38

colubriforme ____________________________ 38

italicum _______________________________ 18, 38

./wemi _________________20,3S; pl. 10 

italicum _______________________20, 3S; pl. 10

sp __________________________ 20 

(Aveyroniceras) italicum __________________ 38

Protogrammoceras _________________________2,18, 41

argutum ________________________18, 21, 41

paltum _________________________ 18, 21,

(Pseudoamaltheus) engelhardti, Amaltheus ______

Pseudolioceras ____________________________2,

compactile____________________________18,

lythense______________________________18,

maclintocki _____________________________

whiteavesi ______________________________

sp _________________21, 2247; pi.

pseudoradians, Ammonites ___________________

Arieticeras _____________________________

Leptaleoceras ___________________ 18, 21, 40;

Psiloceras canadense ________________________

planorbis ________________________20, 22, 2i

plicatum _______________________________

Psiloceras (Psiloceras) ________________6, 12, 28,

(Caloceras) __________.

(Curviceras) columbiae. 

(Franziceras) ________.

ruidum ______________________ 12, 22, 2<.

sp ___________________17,19, 2 

(Psiloceras), Psiloceras _______________6, 12, 28,

Psiloceratidae ______________________________

Puale Bay _______________2, 11,12,13,

29, 30, 31, 33,

Puale Bay area ______________________________

! pl. 12 

17,38 

18,41 

19, 41 

19,41 

41 

11

11,12 

40 

40

pl. 11 

15,31 

8; pl. 1 

29

29,31 

19 

29 

31

12,31

?; pl. 1

9; pl. 1

29,31

2,28

18,28

42,43

33

Queen Charlotte Islands ___________2, 35, 36, 37

radiatum, Paltechioceras (Orthechioceras) _______ 34

Radstockiceras ______________________________ 2

Rainy Pass _____________________ 10 

raricostatum zone, Echioceras _________4, 13, 15, 34, 35

Red Hill _______________________ 18 

retrorsicosta, Arieticeras _____________________ 40

ruidum, Psiloceras (Franziceras) ____12, 19, 22, 29; pl. 2

rursicostatum, Paracaloceras __________13, 22, 33; pl. 6

Sadlerochit River __________________ 18 

Sagavanirktok River _______________ 4, 5 

Schlotheima ______________________________2, 12, 31

angulata Zone ___________________ 12 

donar __________________________________ 31

montana _______________________________ 31

sp _______________________22, 31; pl. 2 

(Waehneroceras) portlocki _________________ 30

Schlotheimiidae __________________ 2, 4 

Seldovia _______________________ 13 

Seldovia area ______________12, 15, 29, 32, 33 

Seldovia Bay ____________________ 10 

semicostatum, Arnioceras ____________________ 12, 15

semiplicatum, Entolium ___________________16, 17, 34

Shellabarger and Rainy Pass areas ________ 10 

Shellabarger Pass _________________ 10 

simile, Aegasteroceras ________________________ 3

Simpson test well No. 1 _______________ 37 

Sinemurian ______________4, 5, 7,10,11,12,13 

ammonites _____________________ 12 

South Barrow No. 12 well _____________ 29 

South Barrrow test well No. 12 _________31, 32,33 

South Barrow test well No. 3 ________32,37, 38, 39 

Spike Mountain ___________________ 6 

spinatum, Pleuroceras _______________________ 38

stokesi, Amaltheus ___________7,17,18,19,21,37; pl. 10

sublaqueus, Laqueoceras __________________22,30; pl. 3

submuticum, Crucilobiceras _______________21, 35; pl. 7
INDEX 49

subtrumffulare, Apoderoceras ________

Deroceras ____________________.

.18, 21, 35; pi. 8 

._____ 35

tailleuri, Otapiria _________________________5, 16, 17

Talkeetna (B-6) quadrangle ____________ 10

Talkeetna (C-6) quadrangle ___________ 10, 32

Talkeetna Formation ________8,10, 33, 34, 35, 36,

37, 38, 39, 40, 41, 42, 43

Talkeetna Mountains __________2, 7, 8,12,15,17,

18, 33, 34, 35, 36, 37,

38, 39, 40, 41, 42, 43

tenerum, Aegoceras __________________________ 30

Waehneroceras ___________________22, 30, 31; pi. 2

tenuicostata, Brodieia _______________________ 21, 42

nodosa, Brodieia _______________________42', pi. 12

Hildoceras 

(Brodiceras) ______________________________ 42

Toarcian _________________4, 5, 7, 10,11,18

ammonites ___________________ 18

toxophorum, Discamphiceras ______________22, 29; pi. 1

Tragophylloceras

ibex Zone _________________18, 35, 37, 38

Triassic _____ 

Tropidoceras .

11

2,37

actaeon _______________________18, 20, 35, 37; pi. 8

tumefacta, Phymatoceras _____________________ 42

turneri, Caenisites __________________________ 12

U

Uptonia ________________2, 5, 17, 18, 36, 37, 38 

dayiceroides _____________________ 18, 20, 36; pi. 9

jamesoni _________________________ 16, 1936; pi. 9

Zone ________________17,18, 35, 37, 38 

sp ______________________17, 19, 36; pi. 9 

sp. A ______________________20, 36; pi. 8 

sp. B ______________________21, 37; pi. 9

V

variabile, Harpoceras ________________________ 43

variabilis, Ammonites ________________________ 43

Haugia ____________________________21, 43; pi. 12

Vermiceras bavaricum mexicanum _____________ 34

multicostatum ___________________________ 15

W

Waehneroceras ______________________2, 12, 28, 29, 30

curviornatum ___________________________ 30

portlocki _________________22, 30; pi. 2 

tenerum ____________________________22, 30; pi. 2

sp _____________________17, 30; pi. 2 

(Waehneroceras) portlocki, Schlothemia. _________ 30

whiteavesi, Pseudolioceras ____________________ 11

Wide Bay ______________________ 30 

Wide Bay areas ___________________ 12 

Wide Bay test well No. 1 ______________ 30 

Wrangell Mountains _______7,12,13,15,17,18, 28, 

30, 33, 34, 35, 36, 37, 38, 40

Xipheroceratinae __________________ 34 

Y

Yakutat District ___________________ 17 

Yakutat D-4 quadrangle ______________ 37

„• U.S. GOVERNMENT PRINTING OFFICE; 1981— 341-614'187

PLATES 1-12

Contact photographs of the plates in this report are available, at

cost, from U.S. Geological Survey Library, Federal Center,

Denver, Colorado 80225
PLATE 1

[Figures natural size unless otherwise indicated]

FIGURES 1, 2. Psiloceras cf. P. planorbis (J. de C. Sowerby) (p. 28).

1. Specimen, USNM 247950, from USGS Mesozoic loc. 29891.

2. Specimen, USNM 247951, from USGS Mesozoic loc. M1738. 

3, 4, 8-10. Discamphiceras cf. D. toxophorum Waehner (p. 29).

3. Specimen, USNM 247960, from Richfield Oil Co. loc. 3002.

4. Specimen, USNM 247958, from USGS Mesozoic loc. 3110. 

8. Specimen, USNM 247961, from Richfield Oil Co. loc. 3002.

9,10. Crushed fragment and rubber imprint of external mold of one specimen, USNM 247959, from USGS Mesozoic loc. 25694. 

5-7. Discamphiceras sp. (p. 29).

Rubber imprints of three external molds, USNM 247962, from USGS Mesozoic loc. 29890. 

11, 15-17. Psiloceras (Franziceras) sp. ind. (p. 29).

11, 15, 16. Ventral and lateral views of specimen, USNM 247956, from South Barrow test well No. 12 at depth of 2,170.5 ft

(661.4 m).

17. Specimen, USNM 247957 from USGS Mesozoic loc. 29742. 

12-14,18-24. Psiloceras (Franziceras) cf. P. (F.) ruidum Buckman (p. 29).

12. Rubber imprint of external mold (x 2) of a specimen, USNM 247952, from USGS Mesozoic loc. 29738.

13. 14. Rubber imprint of external mold (x 2), specimen, USNM 247954, from USGS Mesozoic loc. 29738.

18-20. Rubber imprint of external mold and views of internal mold of a specimen, USNM 247955, from USGS Mesozoic loc.

21242. 

21-24. Rubber imprints (x 2) and suture line (x 4) of one specimen, USNM 247953, from USGS Mesozoic loc. 29738.
GEOLOGICAL SURVEY

IrTKx^a

PROFESSIONAL PAPER 1148 PLATE 1

-*'

22 ^^^^pr- 23

PSILOCERAS, P. (FRANZICERAS), AND DISCAMPHICERAS

24
PLATE 2

[Figures natural size unless otherwise indicated]

FIGURES 1-6. Waehneroceras cf. W. tenerum (Neumayr) (p. 30).

1-3. Three specimens, USNM 247964, from Richfield Oil Co. loc. 3002. Figure 1 is a rubber imprint of an external mold. 

4, 5. Specimen, USNM 247965, from USGS Mesozoic loc. 19803. Figure 5 below fracture is an external mold.

6. Specimen, USNM 247966, from USGS Mesozoic loc. 25694. 

7, 10-15. Waehneroceras cf. W. portlocki (Wright) (p. 30).

7. Specimen, USNM 247971, from USGS Mesozoic loc. 25694.

10. Specimen, USNM 247969, from USGS Mesozoic loc. 12075.

11. Specimen, USNM 247970, from USGS Mesozoic loc. 12394.

12. Specimen, USNM 247967, from Richfield Oil Co. loc. 3002.

13. Specimen, USNM 247968, from USGS Mesozoic loc. 3110.

14. 15. Two specimens, USNM 247972, from Richfield Oil Co., Wide Bay test No. 1 at depth of 2,235-2,236 ft (681 m). 

8, 9. Waehneroceras! sp. (p. 30).

Ventral and lateral views (x 2) of specimen, USNM 247973, from the South Barrow test well No. 12 at depth of 2,181.5 ft (665 m). 

16, 17. Schlotheimia sp. (p. 31).

Specimen, USNM 247974, from USGS Mesozoic loc. 10820. 

18-21, 24-28. Badouxia canadensis (Frebold) (p. 31)

18, 19. Hypotype, USNM 247977, from Richfield Oil Co. loc. 1240. 

20, 21. Hypotype, USNM 247976, from USGS Mesozoic loc. 31266. 

24, 28. Lateral views of hypotype, USNM 247975, from USGS Mesozoic loc. 31372. Figure 24 is a rubber imprint of the

external mold.

25-27. Specimen, USNM 247975, from USGS Mesozoic loc. 31266. 

22, 23. Badouxia columbiae (Frebold) (p. 31).

Hypotype, USNM 247978, from USGS Mesozoic loc. 31264.

22, 23. Hypotype, USNM 247978, from USGS Mesozoic loc. 31264.
GEOLOGICAL SURVEY

•*?&- £bxs( .

PROFESSIONAL PAPER 1148 PLATE 2

WAEHNEROCERAS, SCHLOTHEIMIA, AND BADOUXIA
PLATE 3

[Figures natural size unless otherwise indicated]

FIGURES 1-3. Charmasseiceras cf. C. marmoreum (Oppel) (p. 31).

Lateral views of three specimens, USNM 247979, from the South Barrow test well No. 12 at depth of 2,061.5 ft (628 m). 

4-10. Charmasseiceras sp. (p. 31).

4-6, 9,10. Suture line (x 4) and lateral and ventral views of same specimen (x 2 and x 6), USNM 247981, from the South Barrow test well No. 3 at depth of 2,412 ft (735 m).

7, 8. Lateral and ventral views of specimen, USNM 247980, from the South Barrow test well No. 12 at depth of 2,056 ft (627 m). 

11, 12. Paltechioceras (Orthechioceras!) sp. (p. 34).

Rubber imprint of external mold (fig. 11) and ventral view of specimen, USNM 248003, from USGS Mesozoic loc. 31261. 

13. Laqiteoceras cf. L. siMaqweus (Waehner) (p. 30).

Rubber imprint of external mold, USNM 247963, from Richfield Oil Co. loc. 3002.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE 3

CHARM ASSEICERAS, PALTECHIOCERAS, AND LAQUEOCERAS
PLATE 4

[All figures are natural size]

FIGURES 1-5. Coroniceras sp. A (p. 32).

Three specimens, USNM 247982, from USGS Mesozoic loc. 30908. Ventral and lateral views of one specimen are shown in figures 1 and 3. Same views of another specimen are shown in figures 2 and 4. 

6-10. Coronweras sp. B (p. 32).

6. Rubber imprint of external mold of specimen, USNM 247983, from the South Barrow test well No. 12 at depth of 1,987.5 ft

(605.8 m).

7-10. Two specimens, USNM 247984, from the South Barrow test well No. 12 at depth of 1,987.6 feet (605.8 m). Ventral and 

lateral views of one specimen are shown in figures 7 and 10. Same views of another specimen are shown in figures 8 and 9. 

11-13. Arietites cf. A. bucklandi (Sowerby) (p. 32).

Figure 13 probably represents an inner whorl of specimen shown in figures 11 and 12, USNM 108778, from the Avak test well

No. 1 at depth of 1,836 ft (560 m). 

14. Coronweras sp. C (p. 32).

Rubber imprint of external mold, USNM 247985, from the South Barrow test well No. 3 at depth of 2,470 ft (753 m). 

15-22. Paltechioceras cf. P. harbledownense (Crickmay) (p. 34).

15, 16. Rubber imprint and external mold of specimen, USNM 248000, from USGS Mesozoic loc. 31174. 

17, 22. Specimens, USNM 248001, from USGS Mesozoic loc. 30139.

18-21. Ventral and lateral views of two specimens, USNM 248002, from USGS Mesozoic loc. 28661. 

23-25. Coroniceras (Paracoronweras) sp. (p. 32).

Two specimens, USNM 247986, from USGS Mesozoic loc. 31128. Figure 22 represents a rubber imprint of the inner whorls. 

Figures 23 and 24 show lateral and ventral views of an outer whorl.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE 4

CORONICERAS, C. (PARACORONICERAS), ARIETITES, AND PALTECHIOCERAS
PLATE 5

[Figures natural size unless otherwise indicated]

FIGURES 1-4. Arctoasteroceras jeletzkyi Frebold (p. 33).

1, 2. Hypotype, USNM 247999, from USGS Mesozoic loc. 31261. 

3, 4. Hypotype, USNM 247998, from USGS Mesozoic loc. 31261. 

5, 6, 12-15. Arnioceras sp. juv. (p. 33).

5, 6. Ventral and lateral views.

12, 13. Ventral and lateral views.

14,15. Rubber imprints of two external molds showing smooth inner whorls. Specimens, USNM 247990, from the South Barrow

test well No. 12 at depth of 2,056 ft (626.7 m). 

7, 8. Crucilobiceras cf. C. crucilobatum Buckman (p. 34).

7. Laterally .crushed small specimen (x 2), USNM 248005, from USGS Mesozoic loc. 14030.

8. Rubber imprint of external mold of large specimen, USNM 248004, from USGS Mesozoic loc. 14472. 

9-11, 16-24. Arn-ioceras cf. A. densicosta (Quenstedt) (p. 33).

9,16,17. Rubber imprint of inner whorls (fig. 9) and suture line (x 2) of one specimen, USNM 247987, from USGS Mesozoic loc.

16229. 

10, 11, 18, 19, 22-24. Five specimens, USNM 247988, from USGS Mesozoic loc. 16229. Ventral and lateral views of one

specimen are shown in figures 10 and 11. Same views of another specimen are shown in figures 18 and 19. Figures 22-24

represent rubber imprints of external molds. 

20, 21. Lateral and ventral view of specimen, USNM 247989, from USGS Mesozoic loc. 21237.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE 5

ARCTOASTEROCERAS, ARNIOCERAS, AND CRUCILOBICERAS
PLATE 6

[All figures are natural size]

FIGURES 1-11. Paracaloceras rursicostatum Frebold (p. 33).

1, 2. Hypotype, USNM 247991, from USGS Mesozoic loc. 12396.

3. 5. Hypotype, USNM 248070, from USGS Mesozoic loc. 31372.

4. Hypotype, USNM 247996, from USGS Mesozoic loc. 10820.

6. Hypotype, USNM 247997, from USGS Mesozoic loc. 10820.

7. 11. Hypotype, USNM 247993, from Richfield Oil Co. loc. 1241.

8. Hypotype, USNM 247995, from USGS Mesozoic loc. 31266.

9. Hypotype, USNM 247994, from USGS Mesozoic loc. 2981.

10. Hypotype, USNM 247992, from USGS Mesozoic loc. 12396.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE 6
PLATE 7

[All figures are natural size]

FIGURES 1-3. Crucilobiceras cf. C. submuticum (Oppel) (p. 33).

1, 2. Specimen, USNM 248008, from USGS Mesozoic loc. 6706. 

3. Specimen, USNM 248009, from USGS Mesozoic loc. 28661. 

4, 5. Crucilobiceras cf. C. densinodulum Buckman (p. 34).

Specimen, USNM 248006, from USGS Mesozoic loc. 28661. 

6-10, 12-15. Crue'dobiceras cf. C. muticum (cT Orbigny) (p. 35).

Six specimens, USNM 248007, from USGS Mesozoic loc. 28661. Figures 9 and 10 represent ventral and lateral views of 

smallest specimen. Figures 12 and 13 represent same views of a fairly large specimen. Figures 14 and 15 represent same 

views of the largest specimen. 

11. Fanninoceras kunae McLearn (p. 36).

Hypotype, USNM 248013, from USGS Mesozoic loc. 27586.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE 7

CRUCILOBICERAS AND FANNINOCERAS
PLATE 8

[Figures natural size unless otherwise indicated]

FIGURES 1-9. Tropidoceras actaeon (d'Orbigny) (p. 37).

1-3. Hypotype, USNM 248021, from USGS Mesozoic loc. 28534.

4-6. Hypotype, USNM 248020, from USGS Mesozoic loc. 28534. Figure 4 is a rubber imprint of the external mold.

7. Hypotype, USNM 248022, from USGS Mesozoic loc. 28534.

8. 9. Hypotype, USNM 248023, from USGS Mesozoic loc. 28534. 

10-12, 15-17. Crucilobiceras cf. C. pacificum Frebold (p. 35).

One specimen, USNM 248010, from USGS Mesozoic loc. 28534. Figures 15-17 (x 2). Figure 12 is a rubber imprint of an external mold of the same specimen. 

13. Uptonia! sp. A. (p. 36).

Specimen, USNM 248018, from USGS Mesozoic loc. 29773. 

14, 18-23. Apoderoceras cf. A. subtriangidare (Young and Bird) (p. 35).

14,18-21. Specimen, USNM 248011, from USGS Mesozoic loc. 6697. Figures 18 and 19 represent the adapical part of the middle whorl shown on figure 21. Figure 14 does not include the cross section of the outermost whorl. Figure 20 is a rubber imprint of the external mold of the same specimen. 

22, 23. Lateral and ventral views of a small specimen, USNM 248012, from USGS Mesozoic loc. M6171.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE

TROPIDOCERAS, CRUCILOBICERAS, UPTONIA1, AND APODEROCERAS
PLATE 9

[Figures natural size unless otherwise indicated]

FIGURES 1-4, 8, 12-16. Uptonia cf. U. dayiceroides Mouterde (p. 36).

1-3. Specimens, USNM 248014, from USGS Mesozoic loc. 28675. 

4, 8, 12-16. Specimens, USNM 248015, from USGS Mesozoic loc. 28671. 

5-7. Uptonia sp. B (p. 37).

Specimen, USNM 248019, from USGS Mesozoic loc. 6697. Figures 5 and 7 are (x 2). 

9-11. Uptonial sp. (p. 36).

Specimen, USNM 248017, from USGS Mesozoic loc. 29775. 

17. Uptonia cf. U. jamesoni (J. de C. Sowerby) (p. 36).

Laterally crushed specimen, USNM 248016, from USGS Mesozoic loc. 29774.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE 9

15
PLATE 10

[Figures natural size unless otherwise indicated]

FIGURES 1, 2, 6-15, 22. Arieticeras cf. A. domarense (Meneghini) (p. 39).

1, 2, 8-10, 15. Specimens, USNM 248033, from USGS Mesozoic loc. 28688. Ventral and lateral views of one specimen are shown in figures 1 and 2. Same views of another specimen are shown in figures 9 and 10.

6. Specimen, USNM 248034, from USGS Mesozoic loc. 29450.

7. Specimen, USNM 248036, from USGS Mesozoic loc. 27586.

11-14. Two specimens, USNM 248035, from USGS Mesozoic loc. 24107. Ventral and lateral views of one specimen

are shown in figures 11 and 12. Same views of another specimen are shown in figures 13 and 14. 

22. Specimen, USNM 248037, from USGS Mesozoic loc. 28531. 

3. Prodactylioceras italicum italicum (Fucini) (p. 38).

Hypotype, USNM 248030, from USGS Mesozoic loc. 28671. 

4, 5. Prodactylioceras cf. P. italicum fucini Fischer (p. 38).

4. Specimen, USNM 248032, from USGS Mesozoic loc. 28673.

5. Specimen, USNM 248031, from USGS Mesozoic loc. 28671. 

16-20. Arieticeras cf. A. algovianum (Oppel) (p. 40).

Specimens, USNM 248038, from USGS Mesozoic loc. 28688. Ventral and lateral views are shown in figures 16 and

17, and also in figures 19 and 20. 

21. Arieticeras sp. (p. 40).

Specimen, USNM 248039, from USGS Mesozoic loc. 28531. 

23, 24. Amaltheus cf. A. stokesi (J. Sowerby) (p. 37).

23. Specimen, USNM 248029, from USGS Mesozoic loc. 30074.

24. Specimen, USNM 248028, from USGS Mesozoic loc. 25941. 

25, 26. Amaltheus margaritatus (Montfort) (p. 37).

25. Hypotype, USNM 248025, from Simpson test well No. 1 at depth of 5,677 ft (1,730m).

26. Hypotype, USNM 248024, from USGS Mesozoic loc. M2441. 

27, 28. Amaltheus stokesi (J. Sowerby) (p. 37).

27. Hypotype, USNM 248026, from USGS Mesozoic loc. 29340.

28. Hypotype, USNM 248027, from USGS Mesozoic loc. 29165.
GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1148 PLATE 10

27 28 

ARIETICERAS, PROD ACTYLIOC ERAS, ARIETICERAS, AND AMALTHEUS
PLATE 11

[Figures natural size unless otherwise indicated]

FIGURE 1. Pseudolioceras sp. (p. 41).

Specimen, USNM 248052, from USGS Mesozoic loc. 19804. 

2, 3, 8. Dactylioceras cf. D. commune (Sowerby) (p. 38).

Specimens, USNM 248047, from USGS Mesozoic loc. 24787. 

4, 5, 9. Dactylioceras (Orthodactylites) kanense McLearn. (p. 39).

Hypotype, USNM 248048, from USGS Mesozoic loc. 29198. Figure 5 is a rubber imprint of an external mold.

6. Dactylioceras (Orthodactylites) cf. D. (0.) directum Buckman (p. 39). 

Specimen, USNM 248049, from USGS Mesozoic loc. 29163.

7. Grammoceras sp. (p. 42).

Specimen, USNM 248053, from USGS Mesozoic loc. 25939. 

10, 15, 16. Eleganticeras sp. juv. (p. 41).

Specimens (x 2), USNM 248050, from USGS Mesozoic loc. 29776. Figure 16 is a ventral view of figure 15. 

11. Harpoceras cf. H. exaratum (Young and Bird) (p. 40).

Specimen, USNM 248044, from USGS Mesozoic loc. 29161. 

12, 13. Leptaleoceras cf. L. pseudoradians (Reynes) (p. 40).

Specimen, USNM 248040, from USGS Mesozoic loc. 29450. 

14. Protogrammoceras cf. P. argutum (Buckman) (p. 41).

Specimen, USNM 248046, from USGS Mesozoic loc. 25941. 

17-23. Fontanelliceras cf. F. fontanellense (Gemmellaro) (p. 40).

7, 18, 23. Specimen, USNM 248043, from USGS Mesozoic loc. 29450. 

19, 20. Specimen, USNM 248041, from USGS Mesozoic loc. 25941. 

21, 22. Specimen, USNM 248042, from USGS Mesozoic loc. 27586.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE 11

PSEUDOLIOCERAS, DACTYLIOCERAS, D. (ORTHODACTYLITES), GRAMMOCERAS, ELEGANTICERAS, 

HARPOCERAS, LEPTALEOCERAS, PROTOGRAMMOCERAS, AND FONTANELLICERAS
PLATE 12

[All figures are natural size]

FIGURES 1, 2, 5. Haugia cf. H. variabilis (d'Orbigny) (p. 43).

Specimens, USNM 248059, from USGS Mesozoic loc. 25318. 

3, 7, 9. Haugia cf. H. compressa Buckman (p. 43).

3, 9. Specimens, USNM 248060, from USGS Mesozoic loc. 24114. 

7. Specimen, USNM 248061, from USGS Mesozoic loc. 19804. 

6. Catacoelocerasi sp. juv. (p. 39).

Specimen, USNM 108758, from South Barrow No. 3 test well at depth of 2,063 ft (629 m). 

4, 10, 15. Haugia cf. H. grandis Buckman (p. 42).

Lateral views of three specimens, USNM 248058, from USGS Mesozoic loc. 24114. Adoral part of figure 4 is an internal

mold. 

8. Brodieia cf. B. tenuicostata var. nodosa Jaworski (p. 42).

Specimen, USNM 248057, from USGS Mesozoic loc. 25940. 

11, 12. Protogrammoceras cf. P. paltum Buckman (p. 41).

Specimen, USNM 248045, from USGS Mesozoic loc. 25941. Figure 12 is a rubber imprint of an external mold. 

13. Pseudolioceras sp. (p. 41).

Specimen, USNM 248051, from USGS Mesozoic loc. 25317. 

14, 16-19. Phymatoceras1! sp. (p. 42).

14, 16. Specimen, USNM 248055, from USGS Mesozoic loc. 25317.

17. 19. Specimen, USNM 248054, from USGS Mesozoic loc. 25317.

18. Specimen, USNM 248056, from USGS Mesozoic loc. 25342.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1148 PLATE 12

17 18 19 

HAUGIA, CATACOELOCERAS, BRODIEIA, PROTOGRAMMOCERAS, 

PSEUDOLIOCERAS, AND PHYMATOCERAS?