Early and Middle Bajocian 

(Middle Jurassic) Ammonites 

from Southern Alaska

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1322
Early and Middle Bajocian 

(Middle Jurassic) Ammonites 

from Southern Alaska

By RALPH W. IMLAY

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1322

Studies of the early and middle Bajocian ammonites of 

southern Alaska provide close age determinations and 

correlations with Europe, Arctic Alaska, Arctic Canada, 

and the Pacific Coast region in general

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1984
DEPARTMENT OF THE INTERIOR 

WILLIAM P. CLARK, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Library of Congress Cataloging in Publication Data

Imlay, Ralph Willard, 1908-

Early and middle Bajocian (Middle Jurassic) ammonites from southern Alaska.

(Geological Survey professional paper ; 1322) 

Bibliography: p.

Supt. of Docs, no.: I 19.16:1322

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

QE807.A5I584 1984 564'.53 84-600032

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

604 South Pickett Street, Alexandria, VA 22304
CONTENTS

Page

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

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

Biological analysis ............................................................................ 1

Stratigraphic summary .................................................................. 6

Wrangell Mountains ................................................................ 6

Talkeetna Mountains ................................................................ 7

West side of Cook Inlet ............................................................ 11

Puale Bay area on the Alaska Peninsula ............................ 11

Wide Bay area on the Alaska Peninsula ............................ 11

Ages and correlations ...................................................................... 15

Wrangell Mountains ................................................................ 15

Talkeetna Mountains ................................................................ 22

West side of Cook Inlet between Tuxedni Bay and

Iniskin Bay .......................................................................... 22

Puale Bay area .......................................................................... 23

Wide Bay area ............................................................................ 23

Ammonite faunal setting ................................................................ 25

Geographic distribution .................................................................. 25

Systematic descriptions .................................................................. -5

Family Hildoceratidae Hyatt, 1867 ...................................... 25

Genus Pseudolioceras Buckman, 1889 ........................ 25

Page

Systematic descriptions Continued

Family Hildoceratidae Hyatt, 1867 Continued

Genus Asthenoceras Buckman, 1899 .......................... 25

Genus Tmetoceras Buckman, 1892 .............................. 27

Family Hammatoceratidae Buckman, 1887 ...................... 27

Genus Hammatoceras Hyatt, 1867 ...................... ..... 27

Genus Erycitoides Westermann, 1964 ........................ 35

Family Sonniniidae Buckman, 1892 .................................... 35

Genus Sonninia Bayle, 1879 ............................................ 35

Genus Fontannesia Buckman, 1902 ............................ 36

Family Oppeliidae Bonavelli, 1894 ...................................... 36

Genus Bradfordia Buckman, 1910 ................................ 36

Family Otoitidae Mascke, 1907 ............................................ 36

Family Sphaeroceratidae Buckman, 1920 ........................ 37

Genus Chondroceras Mascke, 1907 .............................. 37

Family Stephanoceratidae Neumayr, 1875 ...................... 37

Genus Normannites Munier-Chalmas, 1892 .............. 37

Genus Stephanoceras Wadgen, 1869 ............................ 37

Genus Teloceras Mascke, 1907 ...................................... '*"

References cited ............................................................... - .. .... 38

ILLUSTRATIONS

[Plates are at back of report]

PLATE 1. Asthenoceras, Tmetoceras, Hammatoceras, Erycitoides, E. (Kialagvikes), Bradfordia, and Otoites.

2. Pseudolioceras, Sonninia, Fontannesia, Chondroceras, Normannites, Stephanoceras (Skirroceras), and Teloceras.

FIGURE 1. Generalized index map of principal areas of outcrop of Bajocian marine rocks in southern Alaska: (1) Wrangell 

Mountains; (2) Talkeetna Mountains; (3) peninsula between Tuxedni Bay and Chinitna Bay; (4) Iniskin 

Peninsula; (5) Puale Bay; and (6) Wide Bay ........................................................... ............................... .. ..

2-7. Detailed index maps of listed early and middle Bajocian ammonite localities in southern Alaska:

2. In the Wrangell Mountains ....................................................................................................................... . ........ ..

3. In the Talkeetna Mountains .................................................................................................................... .......... ..

4. West side of Cook Inlet between Tuxedni Bay and Chinitna Bay ...................................................... ........ .

5. West of Cook Inlet on the Iniskin Peninsula ............................................................................. ............. ............ .

6. Northeast of Puale Bay on the Alaska Peninsula ........................................ .. .......... ........ . -...... . 

7. At Wide Bay on the Alaska Peninsula ...................................................................................................... - ............

8-15. Diagrams showing:

8. Stratigraphic positions and correlations of Bajocian rocks in southern Alaska ...............................................

9. Stratigraphic positions of some Bajocian ammonite localities west of Cook Inlet between Tuxedni Bay

and Iniskin Bay..............................................................................................................................................................

10. Stratigraphic positions of some Bajocian ammonite localities on the northeast side of Puale Bay on the 

Alaska Peninsula ........................................................................................................................................................

Page

10

12

14

III
IV CONTENTS

Page

FIGURE 11. Stratigraphic positions of some Bajocian ammonite localities near Wide Bay on the Alaska Peninsula .......... 16

12. Stratigraphic and chronologic correlations of some early and middle Bajocian ammonites present in the

Talkeetna Mountains with ammonites present in the Tuxedni Group west of Cook Inlet .......................... 18

13. Stratigraphic and chronologic correlations of some early and middle Bajocian ammonites present along

the west side of Cook Inlet between the Fitz Creek and Tuxedni Bay areas .................................................... 19

14. Stratigraphic and chronologic correlations of some early and middle Bajocian ammonites present near

Wide Bay on the Alaska Peninsula ................................................... ..................................................................... 20

15. Correlations and comparisons of Bajocian ammonite faunas in southern Alaska ................................................ 21

TABLES

Page

TABLE 1. Early and middle Bajocian (Middle Jurassic) ammonite genera and subgenera in southern Alaska showing biological

relationships and relative numbers available for study .... .................................................................................................. 9

2. Geographic distribution of early and middle Bajocian ammonites in the Wrangell and Talkeetna Mountains ...................... 26

3. Geographic distribution of early and middle Bajocian ammonites west of Cook Inlet and northeast of Puale Bay on the

Alaska Peninsula . ....................... ......... ................................................................................................ .............................................. 27

4. Geographic distribution of early and middle Bajocian ammonites near Wide Bay on the Alaska Peninsula ......................... 28

5. Descriptions of middle and lower Bajocian fossil localities in southern Alaska ............................................................................. 30
EARLY AND MIDDLE BAJOCIAN (MIDDLE JURASSIC) AMMONITES

FROM SOUTHERN ALASKA

By RALPH W. IMLAY

ABSTRACT

Early and middle Bajocian (Middle Jurassic) ammonites have 

been found in six areas in southern Alaska over a distance of about 

500 mi (800 km) from the Wrangell Mountains on the east to the 

Wide Bay area of the Alaska Peninsula on the west. In the Wrangell 

Mountains, some float obtained near the base of the Nizina Mountain Formation has furnished the ammonites Chondrocerax, Normatniitex, and Tehccras, which constitute good evidence for a late 

middle Bajocian age not older than the upper part of theS^Mawocerax hnmphriexiannm zone.

In the Nelchina area of the Talkeetna Mountains northeast of 

Anchorage, the Tuxedni Group has furnished ammonites ranging 

in age from latest early Bajocian to early late Bajocian. These 

ammonites from the base upward include (1) Eri/citoides howelli 

(White), representing the Graphoce rax concarum zone; (2) Sonninia 

(Enhoploccrax) bifurcata Westermann, representing the lower part 

of the S<»i n in ia noire rhifi zone; (3) Pa rabigotites craxxieostatux Imlay, 

Bradford]a coxtidcnxa Imlay, and Otoitex, representing the Otoitex 

xaiizei'zone; (4) Normaunite.* rariabilislmlay, Stem matoce rax, Leptox)>hinctex, and Chondrocerax, representing the Stephanoceras 

humphriexiannni zone; and (5) Megasphrieroeerax, Sphaeroceran, 

Cadom itcx, and Nornta n n itex, representing the topmost Strenocerax 

xubfurcataw zone of early late Bajocian age.

An even more complete ammonite succession of early to middle 

Bajocian age has been found on the west side of Cook Inlet between 

Tuxedni Bay and the eastern part of thelniskin Peninsula just west 

of Chinitna Bay. Basally that succession differs from the succession 

in the Talkeetna Mountains by the presence of Tmetocerax xcixxnm 

(Benecke) both below and along with occurrences of Eri/citoidex 

hoici'Ui (White) and by the presence of Emileia, Sonninia, and S. 

(Papilliccrax) between the underlying beds containing Parabigotitex 

and the overlying beds containing Teloeerax, Norman n itex, and 

Chondrocerax. The presence of Tmetoceras below the occurrences of 

Erijcitoidex favors an age slightly older than the Graphocerax conearn m zone of latest early Bajocian age. The presence of Sonninia 

and Em ileia is evidence of an age not younger than the zone of Otoitex 

xaiizei.

The Bajocian ammonite succession at Wide Bay is essentially the 

same as that on the west side of Cook Inlet as high as the bed 

containing Sonninia tii.rednienxix Imlay. The succession at Wide 

Bay, however, has furnished more genera and species and has made 

possible a threefold faunule division of the beds characterized by 

Docidocerax (Pxeiidocidocerax) iridebayenxe.

INTRODUCTION

Most of the early and middle Bajocian (Middle 

Jurassic) ammonite taxa present in southern Alaska

were described by the writer in 1964 and by Gerd 

Westerman in 1964 and 1969 (figs. 1-7). The writer at 

that time dealt mainly with ammonites collected either 

northwest of Cook Inlet between Tuxedni Bay and 

Iniskin Bay or in the eastern part of the Nelchina area 

of the Talkeetna Mountains. Gerd Westermann at 

those times dealt mainly with ammonites of late early 

to early middle Bajocian age that had been collected 

near Wide Bay on the Alaska Peninsula. Most of those 

collections had been made by field geologists working 

for the U.S. Geological Survey, as listed by Imlay 

(1964, p. Bl), who also made extensive collections from 

Bajocian sedimentary rocks in southern Alaska, in 

1948, 1952, 1962, 1972, 1974, and 1977.

The stratigraphic occurrences of the ammonites 

(figs. 8-13) are based mainly on studies by R. L. Detterman (1963) and by J. K. Hartsock (1966, p. 20-34) in 

the area west of Cook Inlet; by Arthur Grantz (1965) in 

the Nelchina area of the Talkeetna Mountains; by E. M. 

MacKevett, Jr. (1971, p. 16,17), in the Wrangell Mountains; and by R. L. Detterman and associates (1977, 

1980, and 1981) in the Paule Bay and Wide Bay areas 

of the Alaska Peninsula.

Only those taxa are described herein that have not 

previously been identified or described, or for which 

new biologic, stratigraphic, or geographic data are 

now available.

BIOLOGICAL ANALYSIS

The U.S. Geological Survey's fossil collections from 

southern Alaska contain at least 1,224 ammonite specimens of early and middle Bajocian age. Their distribution by genus, subgenus, subfamily, and family is 

shown in table 1. Among the families, the Hammatoceratidae comprise about 28% percent of the total number 

of specimens; the Stephaneroceratidae, nearly 19 percent; the Sonniniidae, 8% percent; the Sphaeroceratidae and Perisphinctidae, each a little more than 8 

percent; the Oppeliidae, 7% percent; the Otoitidae, 6% 

percent; the Phylloceratidae and Hildoceratidae, each
EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

124°

R t T I CAPt. Barrow

C I F I r

FIGURE 1. Principal areas of outcrop of Bajocian marine rocks in southern Alaska: (1) Wrangell Mountains; (2) Talkeetna Mountains; (3) Peninsula between Tuxedni Bay and Chinitna Bay; (4) Iniskin Peninsula; (5) Puale Bay; and (6) Wide Bay.
BIOLOGICAL ANALYSIS

142°50

BT35'

B1°30'

FIGURE 2. Listed early and middle Bajocian ammonite locality in the Wrangell Mountains. Number refers to that given in table 5.
148°30'

EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA 

148° 147°30' 147°00'

62°15'

 62°00'

61°45'

FIGURE 3. Listed early and middle Bajocian ammonite localities in the Talkeetna Mountains. Numbers refer to those given in table 5.
BIOLOGICAL ANALYSIS

152°55' 50' 45' 40' 152°35'

60°10'

60°05'

60°00'

FIGURE 4. Listed early and middle Bajocian ammonite localities at the west side of Cook Inlet between Tuxedni Bay and Chinitna Bay.

Numbers refer to those given in table 5.
EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

59°50' 

FIGURE 5. Listed early and middle Bajocian ammonite locality west of Cook Inlet on the Iniskin Peninsula in the Iniskin Bay Association

well 1. Number refers to that given in table 5.

about 6 percent; and the Lytoceratidae, Strigoceratidae, and Haploceratidae combined, only ll/2 percent. 

The characteristics of most of the genera, subgenera 

and species present have been discussed by the writer 

in previous publications (Imlay, 1964, p. B3-B6; 1973, 

p. 3-8), and are not repeated herein.

STRATIGRAPHIC SUMMARY

WRANGELL MOUNTAINS

The Middle Jurassic is represented in the Wrangell 

Mountains (fig. 8) only by the Nizina Mountain Formation, which consists mostly of medium-bedded 

graywacke, attains a maximum thickness of 1,500 ft 

(457 m), is overlain unconformably by the Root Glacier 

Formation of Oxfordian to Kimmeridgian (Late Jurassic) age, and is underlain unconformably by the Lubbe 

Creek Formation of Hettangian to Pliensbachian 

(Early Jurassic) age (MacKevett, 1969, p. A42-A46; 

1971, p. 16, 17, 30, 31; Imlay and Detterman, 1973, p. 

11 A). From the base to near the middle part of the 

Nizina Mountain Formation, ammonites have been 

obtained that are probably of earliest Bathonian age 

(Imlay, 1980, p. 4,12-14,16). In addition, a few ammonites (fig. 2) of middle Bajocian age have been collected 

as float, along with many ammonites of probable early 

Bathonian age at U.S. Geological Survey Mesozoic loc. 

28682 (MacKevett, 1969, p. A42-A43; 1971, p. 16, 17, 

30, 31; Imlay, 1980, p. 12-17, 21). These middle Bajocian ammonites were probably derived from the basal 

part of the Nizina Mountain Formation, or from 

underlying beds.
STRATIGRAPHIC SUMMARY

155°25' 155°20'

FOSSIL LOCALITIES

25 Roc loc. 1472

26 Mesozoic loc. 21235

27 Roc loc. 1370

28 Roc loc. 1366

29 and 30 Roc loc. 1351 and 1356

57°45'

Puale Bay

Cape Kekurnoi

Chignik Point

VABM Hike 4 KILOMETERS

2 MILES

FIGURE 6. Listed early and middle Bajocian ammonite localities northeast of Puale Bay on the Alaska Peninsula. The ROC localities represent 

fossil collections of the Richfield Oil Company. Qs, Quaternary sediments; Js, Shelikof Formation (Middle Jurassic); Jk, Kialagyik Formation (Lower and Middle Jurassic); Ju, unnamed Lower Jurassic beds; TRU, unnamed Triassic beds. Dashed lines indicate major faults. 

Formational boundaries determined on the basis of unpublished field data obtained in 1980 and 1981 by R.C. Detterman and associated 

USGS geologists.

TALKEETNA MOUNTAINS

In the Talkeetna Mountains, the Tuxedni Group is 

listed as 700-1,200 ft (213-366 m) thick (Imlay and 

Detterman, 1973, p. 11), and it has been identified at 

many places over a distance of 30 mi (48 km) from the 

Nelchina area in the east to the Boulder Creek area in 

the west (fig. 3). In the Nelchina area as far west as 

Sheep Creek, the Tuxedni Group, according to Arthur 

Grantz (written commun., 1981), consists basally of a 

sandstone that is more than 500 ft (152 m) thick at the 

headwaters of Flat Creek and about 850 ft (260 m) thick 

near Sheep Creek. Above the sandstone is siltstone 

that locally contains a few sandstone beds and is about 

100 ft (30 m) thick.

In the Boulder Creek area of the Talkeetna Mountains the Tuxedni Group is not exposed basally, but is 

at least 550 ft (168 m) thick and well exposed on a 

divide 9.6 km N. 20° E. of the junction of Boulder 

Creek with East Boulder Creek (loc. 17 on fig. 3). Its 

uppermost beds consist of orange-red siltstone that is 

at least 30 ft (9 m) thick locally and is probably as 

much as 131 ft (40 m) thick. Below the orange-red 

siltstone the Tuxedni Group is represented by about 

511 ft (159 m) of sedimentary rocks, consisting, from 

top to bottom, of 145 ft (44 m) of brown-to-gray siltstone, 100-136 ft (30-41 m) covered, 100 ft (30.5 m) of 

sandstone and grit, and 150 ft (46 m) of siltstone containing some beds of graywacke. This sequence has 

been illustrated previously (Imlay, 1980, figs. 3, 4; p. 

10, 11).
EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

FIGURE 7. Listed early and middle Bajocian ammonite localities at Wide Bay on the Alaska Peninsula. Heavy lines indicate contact of

Kialagvik Formation. Numbers refer to those given in table 5.
STRATIGRAPHIC SUMMARY 9

TABLE 1. Early and middle Bajocian (Middle Jurassic) ammonite genera and subgenera in southern Alaska showing biological

relationships and relative numbers available for study

Family

Phylloceratidae ....................

Lytoceratidae .........................

Hildoceratidae ......................

Hammatoceratidae ...............

Sonniniidae .............................

Strigoceratidae .....................

Haploceratidae .....................

Oppeliidae ...............................

Otoitidae .................................

Sphaeroceratidae ........ ........

Stephanoceratidae ..............

Perisphinctidae .....................

Total ...........................

Subfamily Genus or subgenus

............. Phylloceratinae ................. . ......... Phulloceras .....................................

Partschiceras ........... .....................

Calliphvloceratinae ........................ Holeophyloceras ............................

............. Lytoceratinae .................................. Lytoceras ........................................

............. Harpoceratinae ................................ Pseudolioceras ................................

Grammoceratinae .............. . ........ Asthenoceras ......................... ........

Tmetoceratinae ................................ Tmetoceras ......................................

(Tmetoites) .............................

............. Hammatoceratinae ........................ Erycites ...........................................

Erucitoides ......................................

(Kialagvikes) .........................

Eudmetoceras ...............................

(Eudaptetoceras ...................

Hammatoceras .............................

Planammatoceras .......................

............. .............................................................. Sonninia .........................................

(Euhoploceras) ......................

(Papilliceras) .......................

(Alaskin ia) ...........................

(Sontiinites) ...........................

Dorsetensia ...................................

Fontannesia ...................................

Witchcllia .......................................

Pelekodites .....................................

............. .............................................................. Hebeto.njites ...................................

Strigoceras .....................................

......... ... ......... ...................................... . . ......... Lissoceras .......................................

............. Oppeliinae ........................................ Bradfordia .....................................

Praeoppelia ...................................

............. .............................................................. Docidoceras ...................................

(Pseudocidoceras) ...............

Zemistephanus .............................

Otoites .............................................

Pseudotoites ...................................

Abbasites .........................................

E"wf i'te/0 ...........................................

............. .............................................................. Chondroceras .................................

Labrinthoceras .............................

............. .............................................................. Normannites .................................

Tehceras .........................................

Stemmatoceras .............................

Arkelloceras ...................................

Stephanoceras ...............................

(Skirroceras) .........................

............. .............................................................. Leptosphinctes ...............................

Parabigotites .................................

Number of specimens

3

33

33

15

35

4

34

11

3

207

57

6

40

1

4

16

38

14

12

2

3

1

11

2

2

2

4

66

8

1

53

100

6

10

5

9

79

13

92

30

10

1

9

46

1

92

1,224
Standard zones

Stage jn northwest Europe 

(Arkell, 1956)

Wide Bay area

on the 

Alaska Peninsula

Puale Bay area

on the 

Alaska Peninsula

West side of Cook

Inlet from Tuxedni

Bay to Tonnie Creek

Talkeetna 

Mountains

Wrangell 

Mountains

Charact

in so

Parkinsonia parkinsoni

I

Garantiana garantiana

Strenoceras subfurcatum

Stephanoceras

humphriesianum

Otoites sauzei

Sonninia sowerbyi

Kialagvik 

Formation

?L

Kialagvik 

Formation

Graphoceras concauum

Ludwigia murchisonae Not 

identified

Tmetoceras scissum

Not exposed

Leioceras opalinum

Twist Creek 

Siltstone

Megasphaerocer

Normannites uig

Leptosphinctes a

Cynthia Falls 

Sandstone

Fitz Creek 

Siltstone

Nizina

Mountain

Formation

(lower part)

Gaikema 

Sandstone

Red

Glacier

Formation

Tuxedni 

Group

Chondroceras al

Normannites cri

Zemistephanus r

Teloceras itinsae

Stemmatoceras 

Emi/eia and Papi

Sonninia tuxedn

Parabigotites cra

Otoites, Dorseten

Witchellia sutnero

Sonninia

(Euhoploceras)

bifurcata

Docidoceras 

paucinodosum

Eudmedtoceras 

Erycitoides howe

E. (Kialagvikes), 

T. (Tmetoites).

Tmetoceras sciss

FIGURE 8. Stratigraphic positions and correlations of Bajocian rocks in southern Alaska.
STRATIGRAPHIC SUMMARY 11

WEST SIDE OF COOK INLET

Lower and middle Bajocian beds are well exposed 

on the west side of Cook Inlet between Tuxedni Bay 

and Iniskin Bay (figs. 4,9). They are represented from 

bottom to top by the Red Glacier Formation, the Gaikema Sandstone, the Fitz Creek Siltstone, and the 

Cynthia Falls Sandstone of the Tuxedni Group (figs. 

8-9). These formations in combination thicken southward, from about 4,000 ft (1,219 m) north of Fossil 

Point on the south shore of Tuxedni Bay to nearly 8,000 

ft (2,438 m) near Red Glacier, about 11 mi (17.6 km) 

southwest of Fossil Point, but more than half of this 

thickening occurs in the Red Glacier Formation (Detterman and Hartsock, 1966, p. 22, 27, 30, 33). These 

formations, and the overlying Twist Creek Siltstone of 

early late Bajocian age constitute a conformable sequence overlain unconformably by the Bowser Formation of early to late Bathonian age (Imlay, 1980, p. 

5-11), and underlain with angular unconformity by 

the Talkeetna Formation of Early Jurassic age. The 

evidence for the basal unconformity is well shown by 

exposures along the south shore of Tuxedni Bay north 

of Fossil Point and near Red Glacier. Farther south, 

the Red Glacier Formation in many places is in fault 

contact with older formations, and in other places its 

lower part is not exposed. Considerably more lithologic 

and stratigraphic data concerning these formations 

have been presented by Detterman and Hartsock 

(1966, p. 20-34, tables 1-7).

PUALE BAY AREA ON THE ALASKA PENINSULA

The lithologic and stratigraphic features of the 

Kialagvik Formation exposed on the northeast side of 

Puale Bay have been described by Capps (1922, p. 

90-94), Smith and Baker (1924, p. 169-173), Smith 

(1926, p. 66-72), Martin (1926, p. 182-186), and Kellum, Davies, and Swinney (1945). A summary description of those features has been presented more recently 

by Imlay and Detterman (1977, p. 607-611). As shown 

herein on figure 10, the Kialagvik Formation consists 

from bottom to top of three units. The lower unit is 

1,300 ft (396 m) thick, consists mostly of dark-gray-toblack sandy siltstone, but includes many limestone 

concretions in its upper 850 ft (259 m). The middle unit 

is about 100 ft (30 m) thick, consists partly of igneous 

pebbles and boulders, but includes much coarse sandstone. The upper unit is about 500 ft (152 m) thick, 

consists mostly of gray siltstone, contains some ash and 

limestone concretions, and weathers gray. The basal 

beds of the formation near the beach rest sharply on 

beds of Early Jurassic age, but inland toward Alinchak Bay the basal beds are reported by R. L. Detterman (personal commun., 1981) to pass conformably 

downward into beds of Early Jurassic age.

WIDE BAY AREA ON THE ALASKA PENINSULA

The Kialagvik Formation exposed along the northwest side of Wide Bay has been described by Kellum, 

Davies, and Swinney (1945, p. 4-8, figs. 1,2) mainly on 

the basis of the sequences on and near Short Creek and 

Anderson Creek. They note that the formation on 

Short Creek is about 1,750 ft (533 m) thick, consists 

mostly of shale, siltstone, and sandy shale but includes 

some sandstone and conglomerate, and its basal 600 

ft (183 m) of beds is older than the basal beds exposed 

elsewhere near Wide Bay. According to Kellum, 

Davies, and Swinney, the Kialagvik Formation at 

Short Creek from top to bottom is divisible into the 

following lithologic units (fig. 11):

Unit 1, at the top, consists of about 331 ft (91 m) of 

calcareous concretionary shaly siltstone and sandy 

shale that includes one bed of limestone about 60 ft (18 

m) below the top and one bed of sandstone about 200 ft 

(61 m) below the top. This unit has furnished Inoceramus lucifer Eichwald, a few fragmentary ammonites, 

and a well-preserved specimen oiSonninia tuxedniensis Imlay.

Unit 2 consists of about 128 ft (58 m) of siltstone and 

sandy shale that contains some concretions, becomes 

sandier upwards, and contains beds of sandstone at its 

top and bottom. The upper half of this unit has furnished the ammonite genera Parabigotites, Bradfordia, Eudmetoceras, Stephanoceras, Stemmatoceras, 

and Arkelloceras.

Unit 3 consists of about 164 ft (50 m) of blocky 

dark-gray shale that has not furnished any ammonites.

Unit 4 consists of about 190 ft (58 m) of interbedded 

sandstone and sandy shale that is coarser toward the 

top and includes several beds of conglomerate whose 

pebbles were derived from metamorphic rocks and 

attain diameters of 75-100 mm. This unit has furnished such ammonites as Erycitoides hoivelli (White), 

E. (Kialagvikites) kialagvikensis(White), Pseudolioceras whiteavesi(White), Tmetoceraskirki Westermann, 

and T. (Tmetoides) tenue Westermann.

Unit 5 is 366 ft (126 m) thick and is mostly covered. It 

apparently consists, however, mostly of poorly exposed 

gray-to-black shale, siltstone, and sandy shale. The 

unit also includes four widely spaced, fairly well 

exposed beds of gray sandstone that are interbedded 

with some sandy shale and have furnished ammonites. 

Such beds, from 240 to 259 ft (73-79 m) below the top of 

the unit, have furnished the same kinds of ammonite 

that occur in unit 4. Similar beds at the base of the 

unit and also about 328 ft (100 m) higher have furnished 

the ammonite Tmetoceras scissum (Benecke).
12 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

Tuxcdni Bay area Lake Hickcrson area 

Section on Fossil Point Section on divide between Red 

and Bear Creek Glacier and Boulder Creek

TuxedniGroupl (part) in 

Twist Creek 

Siltstone

Cynthia Falls 

Sandstone

Fitz Creek 

Siltstone

Gaikema 

Sandstone

Red Glacier 

Formation

Sandy 

Siltstone 

ash beds

Sandstone, 

some sandy 

Siltstone

Mostly 

massive 

Siltstone

Sandstone, 

thick to 

thin -bedded 

Pebbly 

at base

Siltstone, 

massive

Sandstone, 

massive

Siltstone

Sandstone, 

massive

Siltstone, 

massive

concretions

Sandstone

Siltstone, 

massive, 

sandy

Sandstone, 

massive 

Some pebbles

1 Bowser Formation, 

uppermost formation of 

Tuxedni Group, not shown

METERS FEET 

600 _-2000

500 

 1500

400 

300 1000

200 

 500 

100 

o --o 

A

X 21282 Spiroceras.Lissoceros, 

Megasphaeroceros, Normannites. 

and Leptosphinctes

I ~~ - _

 22707 Chondroceras defonti

I/21280 Chondroceras defonti 

and Sfephonoceros

 21275] Normannites cnckmayi, 

\ 21271 VZemistephanus nchardsoni, 

\21270J Chondroceras defonti. 

Teloceras itinsae and 

x Stemmatoceros tuxedniense 

" 22722 Stephanoceras 

 22721 Oppe/ia sfantoni

,21269 Normannites, Stephanoceras

 21268 Sonninia ruxedmensis, 

Stephanoceras kirschnen, 

Emtleia constncta, Lissoceras

^21261 Parabigotites kialaguikensis

/21233~| Tmetoceras scissum, 

^ \Enjcitoides howelli 

21234J Pseudolioceras whiteavest

- 29341 Pseudo/ioceras cf P 

\ whiteavesi

Siltstone, 

massive 

Ash beds

Sandstone, 

massive to 

thm bedded 

Lower half 

is pebbly 

graywacke

Siltstone, 

massive 

Some sandy 

limestone 

concretions

Sandstone

Siltstone, 

massive

Sandstone

Siltstone, 

some beds of 

sandstone 

Limestone 

in 

upper part

Siltstone, 

massive

Sandstone, 

thin to 

mediumbedded

Sandstone, 

massive

Shale, silty

Siltstone 

Limestone 

concretions 

near top

Sandstone, 

massive

Hard, slaty 

claystone

Sandstone 

^^- ^ ~^_

 22528 Normannites oanabi/is

\

Parabigotites crassicostofus 

 22695 Parabigotites

 24335 Tmetoceras cf T scissum

FIGURE 9. A, Stratigraphic positions of some Bajocian ammonite localities west of Cook Inlet between

Survey Mesozoic localities. B, Chart showing
STRATIGRAPHIC SUMMARY 13

Chinitna Bay area

Section on Gaikema Creek

and on South Shore

Area of Tonnie Creek, 

Twist Creek and Fitz Creek 

Section on Tonnie Creek

B

Siltstone, 

many ash 

beds and 

concretions

Conglomerate 

and sandstone

Siltstone 

/ Sandstone \^

Pebbly 

sandstone

Siltstone. 

sandy

Sandstone, 

thin-bedded

/ Sandstone \ 

some pebbles

Sandstone, 

silty, some 

pebbles

Sandstone,

silty

Sandstone, 

medium to 

thin bedded

Sandstone 

and 

conglomerate

Siltstone, 

massive 

Limestone 

concretions 

common in 

upper part

Sandstone, 

thin-bedded 

to massive

Siltstone 

sandstone 

Siltstone

Mostly 

covered

Sandstone__^

21314 Leptosphmcte 

/ Normanmtes, Sphc 

/ Megasphaeroceras

_ - 

_ 

 19984 Chondroceros 

^ 19981 Stemmatocera 

Stephanoceras (ars< 

and Chondroceros

/ 19978 Zemistephanu 

/ and Normanmtes c

Stephanoceras kirs 

Teloceras and Chc

 26600 Dorsetensia 

 19961 Dorsetensia

^-21296 Dorsetensia, f 

and Stemmatocera

^ 21295 Stemmatocere

 21293 Sonnima (Eu 

and Docidoceras

_ Fautt

s. Oppeha (Liroxyites), 

eroceras and

__ 

_ -~

allani 

s urstnum, 

hnen 

allara

s nchardsoni 

rickmayi ^^.

cricfcmayi, 

fhnen, 

ndroceras

'arabigotites

\s

IS

lop/oceras) bifurcata

Siltstone, 

sandy

Sandstone, 

massive 

pebbly

Siltstone

Sandstone 

pebbly

Siltstone, 

sandy 

Many 

concretions

Sandstone

Siltstone. 

platy, some 

concretions

Sandstone

Sandstone,

silty

j

a

andstone 

nd

Siltstone, 

sandy

Formations of 

Bajocian age 

west of 

Cook Inlet

Twist Creek 

Siltstone

Cynthia Falls 

Sandstone

Rtz Creek 

Siltstone

Gaikema Sandstone

Red Glacier 

Formation

>

=3

ll

3 (-

300ft 

91 m

765ft 

232m

640ft 

195m

600ft 

183m

1760ft 

518m

 21318 Leptosp 

Normanmtes. S 

and Megasphat

/ 21 307 Stephen 

/ 10513 Norman 

 Zermstephanus 

 21771 Oiondn

 20000 Chondn

_ 19997 Norman 

\ Zemisfephanus 

26957 Chondrc

/ 19989 Stephan 

 26601 Brad/or,

Base of exposec

Lake Hickerson 

Glacier Redarea

410ft 

125m

660ft 

201 m

825ft 

251 m

880ft 

268m

4540ft 

1385m

u'nctes, Oppelia (Liroxyites). 

pfioeroceras 

roreras

oceras 

nites, crickmayi and 

rar/oBensis 

Dceras de/onti

oceras a/lani

nites cncfcmavi and 

ricnardsoni 

x;eras defonti

oceras 

iia caribouensis

section

Chinitna Bay area 

Shore andSouth Creek Gaikema 

420ft 

128m

645ft 

197m

1275ft 

389m

850ft 

259m

1530 ft+ 

466 m+

~ 1

Tonnie CreekTwist 

and RtzCreek area

240ft

600ft 

183m

1090ft 

332m

500ft 

152m

300 ft + 

91 m +

Tuxedni Bay and Iniskin Bay (data from Detterman and Hartsock, 1966). Numbers refer to U.S. Geological 

thicknesses of formations in various areas.
14 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

Formation

Shehkof Formation 

(lowest part)

Kialagvik Formation

Unnamed 

Lower Jurassic beds 

(highest part)

Description

Siltstone, gray, 

weathers brown, 

contains ash beds

Siltstone, gray, 

weathers gray, 

does not contain 

ash beds 

152 m (500 ft)

Conglomerate and 

coarse sandstone 

30m (100 ft)

Siltstone, sandy, 

dark-gray to black

Contain thin beds 

of hard, buff 

sandstone and 

becomes sandier

Limestone concretions 

common in 

upper 259 m (850 ft)

Total thickness 

396m (1300 ft)

Sandstone, gray, 

conglomeratic, 

massive 

49m (160 ft)

Siltstone, limy, 

some sandstone 

40m (130 ft)

Charactenstic Fossils

 3106 Codoceras tenuicostatum and 

C (Stenocadoceras) miskinense

 ROC 1472 Dorsetensia? or Witchellia? sp juv

<C Possible unconformity

 21235 Fontannesia cf F carinata Buckman, 

Bradfordia costidensa Imlay and 

Inoceramus lucifer (Eichwald)

/ROC 1370 Tmetoceras scissum (Benecke) and 

/ Erycitoides (Kiahguikes) leuis Westermann

 ROC 1366 Tmetoceras scissum (Benecke) and 

Erycitoides (Kialagvikes) sp 

 ROC 1351 and 1356Pseudo/ioceras whiteauesi, 

(White) and Erycitoides (Kialagvikes) sp

,- 19804 Haugia spp. and Pseudolioceras sp 

= Fault contact 

^ ROC 1303 Coroniceras? sp

 ROC 1.282 Arnioceras

Stage

Late early 

Callovian

Middle middle Bajocian

Late early or early 

middle Bajocian

Late early Bajocian 

Graphoceras concauum zone

Late early Toarcian

Early Sinemurian

FIGURE 10. Stratigraphic positions of some Bajocian ammonite localities on the northeast side of Puale Bay on the Alaska Peninsula.

Localities marked ROC were collected by the Richfield Oil Company.
AGES AND CORRELATIONS 15

The sections measured by Kellum and others (1945, 

fig. 2) along the northwest side of Wide Bay show that 

unit 1 of the Short Creek section passes southwestward 

within 5 km of Anderson Creek, into a sequence 

consisting mostly of pebbly sandstone. Unit 2, as 

determined by ammonites, passes southwestward at 

Anderson Creek into a sequence that consists mostly of 

siltstone and shaly-to-thin-bedded sandstone but that 

contains some pebbly beds at its top and some thin coal 

seams at its base. Unit 3 apparently passes southwestward on Anderson Creek into the lower part of some 

shaly beds that bear coal seams, but probably passes 

also into 60 ft (18 m) of beds represented mostly by a 

covered interval. Unit 4 is represented by cliff-forming 

conglomeratic sandstone on both creeks.

On an unnamed creek about 9 km (6 mi) southwest of 

Short Creek and 1.5-2.0 km north of Alai Creek, the 

Kialagvik Formation near its top bears pebbly sandstone similar in position to that at the top of the formation on Anderson Creek. At least 400 ft (122 m) lower 

occur nearly 200 ft (61 m) of cliff-forming pebbly beds 

similar to the beds in unit 4 on Anderson Creek and 

Short Creek. The intervening beds are poorly exposed, 

are broken by faults, and are difficult to compare with 

the sequences exposed farther northeast.

On the southeast side of Wide Bay the same ammonites that are present in unit 2 at Short Creek are 

present in cliff-forming sandstone northeast of Preston Creek in the NW 1/4 sec. 30, T. 33 S., R. 44 W. 

(USGS Mesozoic Iocs. 19822-19825) and in the NE 

corner of sec. 25, T. 33 S., R. 45 W. (USGS Mesozoic loc. 

32290). Southwest of Preston Creek, unit 2 is likewise 

represented by ammonite-bearing cliff-forming sandstone in the south-central part of sec. 26, T. 33 S., R. 45 

W. (USGS Mesozoic loc. 19798) and in the south-central 

part of sec. 33, T. 33 S., R. 45 W. (USGS Mesozoic Iocs. 

19742 and 19796). This sandstone is characterized 

faunally by the ammonites Parabigotites cmssicostatus Buckman and Bradfordia costidensa Imlay.

On the southeast side of Wide Bay northeast of Preston Creek occur other beds that are probably equivalent to unit 3 of the Short Creek sequence. These beds 

consist mostly of fossiliferous shale that bears concretions, include two sandstone beds and some sandy-tosilty beds, and are at least 174 ft (59 m) thick. They are 

characterized faunally by the ammonites Docidoceras 

(Pseudocidoceras) widebayensis Westermann, Sonninia (Euhoploceras) bifurcata Westermann, and many 

other ammonite taxa (USGS Mesozoic Iocs. 19862, 

19863, 19869, 21251, 21252, 31966, 32292, 32293, 

32295, and 32296).

On the southeast side of Wide Bay, about 3 km 

southwest of the mouth of Preston Creek (loc. 61 on fig. 

15), the beds just mentioned are underlain at the base

of a high bluff at Shell Oil Co. loc. L154 by beds containing the ammonites Tmetoceras kirkiflexicostatum 

Westermann and T. (Tmetoites) cf. T. (T.) ten ue Westermann (1964, p. 354; 1969, p. 12). Such ammonites are 

characteristic of the upper part of the beds containing 

Erycitoides howelli (White), as in unit 4 of the Short 

Creek sequence. E. howelli (White) itself has been 

found near the south end of the southeast side of Wide 

Bay in the SE 1/4 sec. 33, T. 34 S., R. 45 W. at Shell 

Company loc. L555.

These data indicate that the lithologic units within 

the Kialagvik Formation change laterally within fairly 

short distances and, therefore, are difficult to correlate 

without fossils.

AGES AND CORRELATIONS

WRANGELL MOUNTAINS

The existence of beds of middle Bajocian age in the 

Wrangell Mountains is based on a few ammonites (fig. 

8) representing the genera Chondroceras, Normann ites, and Teloceras. These ammonites were collected 

as float at one place near the base of the Nizina Mountain Formation (USGS Mesozoic loc. 28682).

Of these genera, Chondroceras is common nearly 

worldwide iniheStephanocerashumphriesianum zone 

of the middle Bajocian (Imlay, 1973, p. 19) and is 

known from beds of late Bajocian age. Normannites 

ranges upward from the uppermost part of the Otoites 

sauzei zone of middle Bajocian age to the Strenoceras 

subfiu'catum zone of early late Bajocian age. Teloceras 

ranges upward from the Stephanoceras humphriesianum zone to the Garantia garantiana zone of the middle late Bajocian (Imlay, 1973, p. 19; Arkell, 1956, p. 

483). The presence of Chondroceras is good evidence 

for a late middle Bajocian age. The presence of a species resembling Teloceras blagdeni (Sowerby) favors 

an age assignment not older than the upper part of the 

Stephanoceras hnmphriesianum zone (Weisert, 1932, 

p. 185; Arkell, 1956, p. 483). Such an age assignment 

seems reasonable provided the three genera occur in 

association.

In addition, another ammonite faunule of slightly 

younger age has been found at the same locality as the 

3 genera just listed as well as at 10 other localities 

ranging from the base to near the middle of the Nizina 

Mountain Formation (Imlay, 1980, p. 4). This younger 

faunule is herein considered to represent the earliest 

Bathonian rather than the latest Bajocian because (1) 

it does not contain typical late Bajocian ammonites, 

such as Spiroceras, Leptosphinctes, and Sphaeroceras 

(Imlay, 1980, p. 4); (2) it does contain species typical of 

the earliest Bathonian, such as Cranocephalites costidensus (Imlay, 1980, p. 8); and (3) in the Lake Hickerson
Shelikof 

Formation

Kialagvik 

Formation

Anderson Creek

Northwest side of Wide Bay

in sees 2 and 3, T 33 S . R 45 W ,

on Alaska Peninsula

Silry sandstone

- -~^ -^\_

Platy sandstone, 

some thin beds 

of conglomerate

Pebbly sandstone

Pebbly sandstone

Mostly siltstorte

Sandstone and shale, 

some concretions 

and coal seams

Not exposed

Conglomerate 

 -- -~ -^

Sandstone, fjebbly

Sandstone

METERS FEET 

, 1000

300 

200 

100 

 _ 600

 400

 200

0 L- 0

Short Creek

Northwest side of Wide Bay 

in sees 28 and 33, 

T 32 S , R. 40 W , 

on Alaska Peninsula

Parabigotites 

zonule

49776 

 19773,21258,31990

Shale

Sandy shale

i i i i i i i i i i i i i i i Siltstone and 

sandstone, some 

concretions

Siltstone and 

some concretions

Sandstone and 

some conglomerate

-S-21254

Sandy shale

Sandstone, sandy 

shale and 

conglomerate

VI9748

Erycrtoktes howelh 

) zonule

Sandy shale

Not exposed

Sandy shale

Not exposed

Sandstone

Not exposed

Sandy shale

No* exposed

Sandy shale

Not exposed

Siltstone

21257

19747, 

~&21245

 21248

 21247

Northeast of "Preston" Cr

Southeast side of Wide B

NE'A sec. 25, R. 33 S., R. 4

and NWV4 sec. 30, T. 33 S., R 

on Alaska Peninsula

Cliff-forming 

sandstone

Shale sandy

Sandstone cliffs

Shale

Shale and 

silty shale

Sandstone

Not exposed

Shale, some 

limestone concretions

Sandstone

EXPLANATION

Limestone
AGES AND CORRELATIONS 17

til < a ^i

O

O

OH 

05

o

«

 3

o

g

I

a, o!
18 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

Genus and Species

Lower Bajocian

Not 

Identified

I

i

Middle Bajocian

1) -C

° F 

§ I

-c -c

>

Tuxedni Group (part) northwest of Cook Inlet

Red Glacier Formation

c/)

a> <£ 

2. ^

|^

U

Ho/cop/iy//oceras costisparsum Imlay ...........

Erycitoides howelli (White) ..................

P/anammatoceras cf. P. benneri (Hoffman) ......

Eudmetoceras (Euaptetoceras) amplectens Buckman 

Sonninia tuxedniensis Imlay .................

cf. S. projectifer (Buckman) ..................

(Sonninites) cf. S. (S.) simulans Buckman .......

(Euhoploceras) bifurcata Buckman .............

(Ahskinia) cf. S. (A.) alaskensis Westermann _____

(Papllliceras) cf. S. (P.) espinozitensis (Tornquist) _ _ _ 

Dorsetensia cf. D. adnata Imlay ______________

Witchellia sp. _.._____._______..__.-__.__.

Lissoceras cf. L. isemicostulatum Buckman ______

Bradfordia costidensa Imlay _________________

B. ? caribouensis Imlay .__.__.__.__________.

Otoites cf. O. pauper Westermann _____________

Normannites uariabilis Imlay __________________

Stephanoceras obesum Imlay _________________

(Skirroceras) juhlei Imlay ____________________

(S.) nelchinanum Imlay _____________________

Stemmatoceras cf. S. palliseri (McLearn) ________

Labyrint/ioceras glabrum Imlay

Chondroceras allani (McLearn) _______________

Parabigotites crassicostatus Imlay ______________

Leptosphinctes euolutus Imlay _______________

FIGURE 12. Stratigraphic and chronologic correlations of some early and middle Bajocian ammonites present in the Talkeetna Mountains

with ammonites present in the Tuxedni Group west of Cook Inlet.
AGES AND CORRELATIONS 19

Genus and Species

Lower Bajocian

Not 

Identified

o

I

o

Middle Bajocian

o

CO

.

° F

§ I

.c -c

t 

00

Tuxedni Group (part) northwest of Cook Inlet

Red Glacier Formation

_. a> £ c

£ o

2$'a c

r U n <c c^

Ho/cophy//oceras costisparsum Imlay ..........

Tmetoceras scissum (Benecke) ..............

Pseudolissoceras cf. P. whiteavesi (White) ......

Erycitoides howelli (White) .................

cf. E. howelli (White) .................

(Kialagvikes) cf. E. (K.) kia/aguikensis (White) 

Sonninia tuxedniensis Imlay ................

(Papillicems) cf. S. (P.) arenata (Quenstedt) .

(Euhop/oceras) bifurcata Westermann ......

Dorsetensia adnata (Imlay) .................

Strigoceras sp. ..........................

Lissoceras cf. L. semicostulatum Buckman ......

Lissoceras bakeri Imlay _...,..............

Bradfordia? caribouensis Imlay ..............

Oppe/ia stantoni Imlay ....................

Docidoceras? paucinodum Westermann ........

Otoites cf. O. contractus (Sowerby) ...........

O? filicostatus Imlay ......................

Emi/eia constricta Imlay

Chondroceras de/onti (McLearn) .............

a//ani (McLearn) .....................

Normannites variables (Imlay) ..............

itinsae (McLearn) .....................

crickmayi (McLeam) .................

Stephanoceras cf. S. nodosum (Quenstedt) .....

sp _..._...._..............._....

(Skirroceras) kirschneri Imlay ...........

(Skirroceras) juhlei Imlay ._.__.._......

Stemmatoceras cf. S. palliseri (McLearn)

ursinum Imlay ........._............

Teloceras itinsae (McLeam) ................

Zemistephanus richardsoni (Whiteaves) ........

car/ottensis (Whiteaves) ...............

Parabigotites crassicostatus Imlay ......_....._

kiahgvikensis (Imlay) -.........._.....

sp ..............................

FIGURE 13. Stratigraphic and chronologic correlations of some early and middle Bajocian ammonites present along the west side of Cook

Inlet between the Fitz Creek and Tuxedni Bay areas in south-central Alaska.
20 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

Genus and Species

Lower Bajocian

.CO 

T3

Not exposed

Middle Bajocian

Kialagvik Formation

CO

Absent

Phy//oceras cf. P. kunthi Neumayr ..............

Ho/cophy//oceras costisparsum Imlay .............

Pseudo/ioceras whiteauesi (White) ...............

mac/.ntocld fastigatum Westermann ..........

costistriatum Westermann .................

Asthenoceras aff. A. nan nodes (Buckman) .........

Tmetoceras scissum (Benecke) ........._.......

kirki Westermann ......................

kirfci flexicostatum Westermann .............

(Tmetoites) tenue Westermann ..............

Planammatoceras aff. P. benneri (Hoffman) ........

Eudmetocems cf. E. eudmetum jaworskii Westermann

(Euaptetoceras) amplectens (Buckman) ........

(£.) klimakomphalum discoidale Westermann . _ .

(£.) aff. ,£. (£.) nuc/eospinosum Westermann ... 

Erycites im/ayi Westermann ...................

Erycitoides howelli (White) ........-....-----..

pro/undus Westermann ____........______.

teres Westermann .......................

paucispinosus Westermann .................

(Kialagvikes) kialagvikensis (White) ...........

(K.) spinarus Westermann .................

(K.) levis Westermann ....................

Abbasites p/atystomus Westermann ..............

Sonninia tuxedniensis Imlay __...____....____..

(Papi/Viceras) cf. S. (P.) arenata (Quenstedt) ....

(Euhop/oceras) bifurcata Westermann _________

(Alaskinia) alaskensis Westermann .____..___. 

Witchellia sutneroides Westermann ____.._____... 

Pelekodites cf. P. pelekus Buckman _.._____.___. 

Hebetoxy.tes aff. H. hebes Buckman ..___.____._ 

Brad/ordia costidensa Imlay ._....___..________

?(Praeoppe/ia) oppe/i/ormis Westermann _______

Docidoceras aff. D. longaluum (Vacek) _.__.____.,

(Pseudocidoceras) widebayense Westermann

(P.) camachoi Westermann .____.___.___._,

?(P.?) paucinodum Westermann _____________

Pseudotoites cf. P. argentinus Arkell _____________

cf. P. transatlanticus (Tornquist) _____________

Otoites sp. ________________________________

Stephanoceros sp. ..___..____.__..___.__.__,

Stemmatoceras sp. __..____.._______.___.___.

Arlce//oceras sp. .__...____.____.__.___..___.

Parabigotites kialaguikensis (Imlay) ____.___.____.

crassicostatus Imlay ___...___..___._..___.

FIGURE 14. Stratigraphic and chronologic correlations of some early and middle Bajocian ammonites present near Wide Bay on the

Alaska Peninsula.
Bajocian

1

0> 

T3 

T3

§

Lower (Aalenian)

Standard zones 

in northwest Europe 

(Arkell, 1956)

Parkinsonia parkinsoni

Garantiana garantiana

Strenoceras 

sub/urcatum

Stephanoceras 

humphriesianum

Otoites sauzei

Sonninia soiuerbyi

Graphoceras concauum

Ludiuigia murchisonae

Tmetoceras scissum

Leioceras opa/inum

Characteristic ammonites 

in the Wide Bay area 

on the Alaska Peninsula

Sonninia tuxedniensis

Parabigotites crassicostatus, Otoites, 

Bradfordia costidensa, and Stephanoceras

lVitche//ia sutneroides . .

Sonninia Doadocera* 

(Euhoploceras) (Pseudoadbi/urcata oceras)

Docidoceras widebayense 

(Paucinodosum)

Erycitoides howelli, 

E. (Kia/aguikes) kia/uguikensis, 

Tmetoceras (common), Abbasites (rare), 

and Eudmetoceras (Euaptetoceras)

Tmetoceras scissum 

and Pseudo/ioceras

Characteristic ammonites 

in the west side of Cook Inlet 

between Tuxedni Bay and Iniskin Bay

Megasphaeroceras rotundum, 

Normannites uigorosus, Leptosphinctes, 

Sphaeroceras, and Liroxyites

Chondroceras a//ani 

Normannites crickmayi, 

Zemistephanus richardsoni, 

Te/oceras itinsae, and 

Stemmatoceras tuxedniense

Emi/eia and Sonninia (Papi//iceras)

Sonninia tuxedniensis

Stephanoceras 

kirschneri

Parabigotites crassicostatus, Stemmato - 

ceras, and Dorsetensia adnata

Sonninia (Euhop/oceras) bi/urcata

Erycitoides howelli 

and Tmetoceras scissum

Tmetoceras scissum

eudo/ioceras 

Eudmetocera

&

Characteristic a

in the Talkeetna 

Leptosphinctes

Chondroceras a//ani, 

Normannites uariabi/is, 

Stemmatoceras

/Parabigotites crassicosta

/ Bradfordia costidensa, S

Dorsetensia, lVitche//ia, 

Sonninia

Sonninia (Euhop/ocera

S. (A/askoceras), and S

Erycitoides howelli

FIGURE 15. Correlations and comparisons of Bajocian ammonite faunas in southern Alaska.
22 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

area west of Cook Inlet the species C. coxtidcnxnx is 

associated with the Bathonian genera Sicmcradzkici.

TALKEETNA MOUNTAINS

In the Nelchina area of the Talkeetna Mountains, 

ammonites of latest early Bajocian to early late Bajocian ages have been found in the Tuxedni Group (figs. 

8,12,15). The latest early Bajocian zone of Graphocvrax 

c<»ic<trHni is represented by one specimen of Enjcitoidt'x hoH'clli (White) obtained as float from the basal 

99 ft (30 m) of sandstone at Sheep Creek (USGS 

Mesozoic loc. 24135). The next younger zone of Sonnin {a Hoiwrbi/i is represented by Sonn in ia (Euhoplocerax) 

bifnrcata Westermann obtained from the upper part 

of the same sandstone (USGS Mesozoic loc. 26723). 

The next younger zone of Otoitex xauzei is represented 

in gray siltstone by Parabigotites craxxicostatux Imlay 

(USGS Mesozoic Iocs. 24113 and 27577), by Bradfordia costidensa Imlay (USGS Mesozoic Iocs. 31728, 

24113, 24215, and 25345), by Otoites (USGS Mesozoic 

loc. 24113), and by Stephanocerasjnhlei Imlay (USGS 

Mesozoic Iocs. 24113 and 24120). The next younger 

zone of Stepha noceras h u mph riesia n u m is represented 

in gray siltstone by Nonnannites rariabilis Imlay 

(USGS Mesozoic loc. 8567), Stemmatoceras (USGS 

Mesozoic loc. 30280), Chondroceras (USGS Mesozoic 

Iocs. 8567, 30280, 30594), and Leptosphincte* (USGS 

Mesozoic loc. 8567). Above follows reddish-gray siltstone that contains ammonites of early late Bajocian 

age, such as Megasphaeroceras, Sphaeroceras, and 

Cadom ites, in association with Norm a n n ite* and Stemmatoceras (Imlay, 1952, p. 978, chart 8C opposite p. 

998; Imlay, 1982, p. 1,7-11).

Among the fossil collections listed, only those from 

USGS Mesozoic localities 24175 and 26723 are definitely from the lower sandstone unit of the Tuxedni 

Group. The others are from the upper siltstone unit, 

with the possible exceptions of USGS Mesozoic localities 27577, 24113, and 31728. As the fossils at the last 

two localities are on landslide scars and the word "sandstone" is not used in their locality descriptions, the 

fossils could be from the upper siltstone unit.

In the Boulder Creek area of the Talkeetna Mountains an incomplete Bajocian sequence about 550 ft 

(168 m) thick was measured on a divide at the head of a 

tributary of Boulder Creek and 6 mi (9.6 km) N. 20° E. 

of the junction of that tributary with East Boulder 

Creek (Imlay, 1980, fig. 3). That incomplete sequence, 

representing the upper part of the Tuxedni Group, 

contains ammonites ranging in age from middle middle Bajocian to early late Bajocian. From the uppermost 30 ft (9 m) of orange-gray siltstone was collected 

the ammonite Megasphaeroceras of early late Bajocian

age. From 69 to 133 ft (21 to 44 m) lower in the sequence 

at USGS Mesozoic loc. 30281 was collected a specimen 

of Witclu'Uia, which genus in Europe ranges through 

most of the zone of Sonninia noircrbni and all of the 

zone of Otoites Hauzci.

Elsewhere in the Boulder Creek area the middle 

Bajocian zone of Otoitexscuizei is represented at USGS 

Mesozoic loc. 30582 by an occurrence of Son)iinia 

tu.redn iensis Imlay, which west of Cook Inlet occurs in 

the upper part of the Red Glacier Formation. In addition, the zone of Stephanocerax hiimphriesianitm is 

represented at USGS Mesozoic Iocs. 30594 and 8567 by 

Chondrocems allani (McLearn), which west of Cook 

Inlet occurs in the Fitz Creek Siltstone and in the 

overlying Cynthia Falls Sandstone. Furthermore, the 

association of that taxon with Nonnannites rariabilis 

Imlay and Leptoxphinctes (>rolntux Imlay at USGS 

Mesozoic loc. 8567 is good evidence for correlation 

with only the upper part of the zone of Stephanoceras 

hitmphriesianum.

The ages of the early and middle Bajocian ammonites that have been found in the Talkeetna Mountains 

are shown herein on figures 12 and 15. Concerning the 

taxa listed on figure 12, the following name changes 

should be noted:

1. Planammatoceras aff. P. berneri (Hoffman) was 

originally described as Sonninia cf. S. patella 

Waagen by Imlay (1964, p. B33, pi. 3, figs. 2-4), 

but was revised by Westermann (1969, p. 24).

2. Eudmetoceras (Enaptetoceras) amplectens Buckman was originally described as Witchellia? 

aguilonia Imlay (1964, p. B35, pi. 4, figs. 1-4, fig. 

9, pi. 5, figs. 4, 7-9), but was revised by Westermann (written commun., 1964).

3. SonninitescLS. simuIausBuckman. was originally 

described as Witchellia cf. W. laevinxcula (J. de 

C. Sowerby) by Imlay (1964, p. B35, pi. 7, figs. 1-5).

4. Sonninia (Euhoploceras) bifnrcata Westermann 

was originally described as Sonninia? n. sp. 

undet. by Imlay (1964, p. B33, pi. 4, figs. 5, 6, 

10-12), but was revised by Westermann (1969, p. 

94).

5. Sonninia (Alaskinia) cf. S. (A.) alaskensis Westermann was originally described as Son n in ia cf. S. 

nodata Buckman by Imlay (1964, p. B33, pi. 2, 

figs. 1, 2), but was revised by Westermann (1969, 

p. 24, 103).

WEST SIDE OF COOK INLET BETWEEN 

TUXEDNI BAY AND INISKIN BAY

The uppermost lower Bajocian zone of Graphoceras 

concavum is fairly well represented on the south side of 

Tuxedni Bay (see figs. 9,13,15). North of Fossil Point
AGES AND CORRELATIONS 23

it is represented by an association of Tmetoceras scissum (Benecke), Erycitoides howelli (White), and Pseudolioceras wh iteavesi (White) at USGS Mesozoic localities 21233 and 21234, which occur from 150 to 480 ft 

(46 to 146 m) above the base of the Red Glacier Formation (see fig. 9). In the Lake Hickerson area, about 11 

mi (17.6 km) southwest of Fossil Point, Tmetoceras 

scissum (Benecke) occurs at USGS Mesozoic locality 

24335 from 900 to 1,100 ft (273 to 334 m) above the base 

of the Red Glacier Formation. Considerably farther 

south, on the Iniskin Peninsula, the ammonite Erycitoides (Kialagrikes) cf. E. (K.) kialagrikertsis (White) 

(Mesozoic loc. 21244F) occurs in a well core drilled at 

a depth of 5,495-5,515 ft (1,675-1,681 m) in Iniskin 

Bay Association well 1 (fig. 5). These ammonites in 

association favor an age assignment to the latest early 

Bajocian (Westermann, 1964, p. 345, 346, fig. 5; 1969, 

p. 15,18), although in southern Alaska Pseudolioceras 

ranges a little higher (Westermann, 1969, p. 17,52-58) 

into beds characterized by Sonninia (Euhoploceras) 

bifurcata Westermann, and Tmetoceras ranges throughout the lower Bajocian.

The ages of the middle Bajocian ammonites west of 

Cook Inlet have been discussed in previous publications (Imlay, 1964, p. 10-14; Imlay, 1973, p. 32, 33; 

Dettermann and Hartsock, 1966, p. 23, 28, 31, 34) and 

are shown herein in figures 13 and 15.

Concerning the taxa listed on figure 13, Dorsetensia 

adnata (Imlay) was originally described as Witchellia 

adnata Imlay (1964, p. B34, pi. 6, figs. 6-10), and 

Parabigotites kialagvikeusis (Imlay), as Normannites 

kialagrikensis Imlay (1964, p. B43, pi. 13, figs. 1-8,10, 

11, 17).

PUALE BAY AREA

The Kialagvik Formation present near and on the 

beach along the northeast side of Puale Bay ranges in 

age from early Toarcian near its base to middle Bajocian near its top (figs. 8 and 10). These ages are based 

on the presence of (1) the early late Toarcian ammonite 

Haugia 30 ft (9 m) above the base of the formation 

(USGS Mesozoic loc. 19804), (2) the early Bajocian 

ammonites Tmetoceras and Erycitoides (Kialagrikes) 

300-400 ft (122-152 m) above the base of the formation, or 900-950 ft (244-274 m) below the massive conglomerate (ROC Iocs. 1351, 1366, and 1370), (3) the 

middle Bajocian ammonites Bradfordia costideusa 

Imlay and Fontannesia cf. F. carinata Buckman 

about 200 ft (61 m) below the massive conglomerate 

(USGS Mesozoic loc. 21235), and (4) Dorsetensia? or 

WitcheUia? of probable late middle Bajocian age near 

the top of the formation and about 500 ft (152 m) above 

the massive conglomerate (Imlay and Detterman, 

1977, p. 609-611).

WIDE BAY AREA

The ammonites found in the Kialagvik Formation in 

the Wide Bay area can be grouped into at least four 

and perhaps five faunal subdivisions, or zonules, 

which from the base up include (1) Tmetoceras scissum, (2) Erycitoides howelli, (3) Docidoceras (Pseudocidoceras) widebayense, (4) Parabigotites crassicostatus, and, possibly, (5) Sonniuia tu.rednieusis (figs. 8, 

11, 14, and 15).

The Tmetoceras scissum zonule is represented n the 

lower 328 ft (100 m) of the Kialagvik Formation 

exposed on Short Creek only by Tmetoceras scissum 

(Benecke) and Pseudolioceras sp. Of these genera, 

Tmetoceras in Eurasia ranges from the zones of Leioccras opalitium to Graphoceras concarum, inclusive. 

Pseudolioceras ranges from the Hildoceras bifrons 

zone in the upper Toarcian to the Sonninia sowerbyi 

zone in the lower Bajocian. As Tmetoceras scissum 

(Benecke) in southern Alaska occurs only a little below 

the beds characterized by Erycitoides howelL it probably is equivalent in age to the zones of Ludwigia 

murchisonaeand Graphoceras concarum of northwest 

Europe.

The zonule of Erycitoides howelli is characterized 

throughout by many occurrences of E. howelli White, 

E. (Kialagrikes) kialagrikensis(White), and Pseudolioceras whiteavesi (White), and by rare occurrences of 

Abbasites platystomus Westermann and Eudmetoceras(Euaptetaoceras) amplectens Buckman. Erycitoides 

howelli is associated in the lower part of its range with 

rare occurrences of Erycites imlayi Westermann and 

some occurrences of Tmetoceras; in only the middle 

part by many occurrences of Erycitoides profundus 

Westermann and E. teres Westermann and a few 

occurrences of E. paucispinosus Westermann; in the 

middle to upper parts by E. (Kialagvikes) spinatus 

Westermann; and in only the upper part by a few 

occurrences of Eudmetoceras cf. E. eudmetum jaworskii Westermann, E. nuleospinosum Westermann, 

Tmetoceras kirki Westermann, T. kirki fle.ricostatum 

Westermann, and T. (Tmetoites) tenue Westermann 

(Westermann, 1964, p. 345-352, figs. 3 and 5).

Based on these stratigraphic occurrences and on an 

abundance of well-preserved ammonites, the faunal 

subdivision characterized by E. howelli was raised by 

Westermann (1964, p. 345-352, fig. 3) to the rank of a 

zone and was divided into three subzones or zonules. Of 

these, the lower zonule is characterized by an abundance of E. howelli and by some Tmetoceras; the middle zonule, by Erycitoides profundus and E. teres; and 

the upper zonule, by Tmetoceras tenue and T.flexicostatum. This division is probably valid, but needs to be 

checked by more field work. Furthermore, the name 

Erycitoides howelli cannot be applied to both a zone
24 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

and a subzone, as was done by Westermann (1964, p. 

345).

The beds characterized by these ammonites are 

correlated by Westermann (1964, p. 346) with the 

upper part of the lower Bajocian of Europe and, probably, with the zone of Graphoceras concavum, as is 

shown by the presence of Tmetoceras, which is not 

known above the concavum zone in Europe, and of 

Eudmetoceras (Euaptetoceras), a submenus that in 

Europe ranges from the middleofiheLudwigia murchinsonae zone into the lower fourth of the Sonninia 

sowerbyi zone (see Imlay, 1973, p. 19, 31).

The Docidoceras (Pseudocidoceras) widebayensezonule, identified to date only on the southeast side of 

Wide Bay, is characterized throughout its lower 372 ft 

(114 m) by an association of the following- ammonite 

species:

Holcophylloceras costisparsum Imlay 

Pseudoliocerasfastigatum Westermann 

P. maclintocki (Raughton) 

P. costistriatum Westermann 

Asthenoceras cf. A. nannodes Buckman 

Planammatoceras aff. P. benneri Hoffman 

Sonninia (Euhoploceras) bifurcato Westermann 

S. (Alaskinia) alaskensis Westermann 

Witchellia sutneroides Westermann 

Fontannesia intermedia Imlay 

Praeoppelia oppelifonnis Westermann 

Docidoceras (Pseudocidoceras) widebayense Westermann

cf. D. (P.) ividebayense Westermann 

D. (P.) camachoi Westermann 

D.? (P.?) pauchinodosum Westermann 

Eudmetoceras (Euaptetoceras) discoidale Westermann 

Pseudotoites cf. P. argentinus Arkell 

P. P. transatlanticus (Tornquist)

The beds characterized by these ammonites were 

correlated by Westermann (1969, p. 20-22, 26) with 

the European zone of Sonninia sowerbyi based on the 

association of the t&xaPseudolioceras, Sonninia (Euhoploceras), Witchellia, and Docidoceras and on the 

absence of such taxa as Chondroceras, Normannites, 

and Stemmatoceras (Imlay, 1973, p. 19, 21, 31).

The Parabigotites crassicostatus zonule is characterized throughout by an association of the following 

taxa:

Phylloceras cf. P. kunthi Neumayr

Holcophylloceras costisparsum Imlay

Eudmetoceras amplectens Buckman

Sonnina (Papilliceras) cf. S. (P.) arenata (Quenstedt)

Dorsetensia adnata (Imlay)

Bradfordia costidensa Imlay

Otoites cf. 0. contractus (J. de C. Sowerby)

Stephanoceras (Skirroceras) cf. S. (S.) leptogyrale

Buckman 

Stemmatoceras sp. 

Arkelloceras sp.

Parabigotites kialagvikensis (Imlay) 

P. crassicostatus Imlay 

P. cf. P. crassicostatus Imlay

The Parabigotites crassicostatus zonule is characterized by many occurrences of Eudmetoceras a mplectens Buckman, Bradfordia costidensa Imlay, Parabigotites crassicostatus Imlay, and P. kialagvikensis 

(Imlay). Among the other taxa present, Sonninia 

(Papilliceras) has been found at three localities and 

the other genera at only one or two localities.

The ammonite zonule characterized by Parabigotites crassicostatus Imlay and Bradfordia costidensa 

Imlay has been found elsewhere in southern Alaska on 

the west side of Cook Inlet and in the Talkeetna Mountains. West of Cook Inlet those taxa occur in the upper 

part of the Red Glacier Formation at stratigraphic 

positions ranging from 252 to 654 ft (77 to 214 m) below 

its top (Imlay, 1964, p. B10-B12). In both areas the 

beds containing those ammonites have been correlated 

with the lower to middle parts of the zone of Otoites 

sauzei by the presence of such genera as Sonninia, 

Dorsetensia, and Lissoceras and by their occurrence 

below such ammonites as Normannites and Chondroceras.

The highest beds in the Kialagvik Formation above 

those containing Parabigotites are dated by the presence of hwceramus lucifer Eichwald as being not 

younger than the zone of Otoites sauzei in Europe. 

That correlation is based on the fact that west of Cook 

Inlet, I. lucifer ranges through the Red Glacier Formation into the Gaikema Sandstone but no higher; and 

that the Gaikema Sandstone on the basis of ammonites 

is correlated with the upper part of the zone of Otoites 

sauzei (Imlay, 1964, p. B7, B12).

The highest beds in the Kialagvik Formation could 

be dated also by the presence of one specimen of Sonninia tuxedniensis Imlay, collected at the southwest 

end of Wide Bay from a sandstone unit exposed on a 

creek that enters the bay from the northwest about 1 

mi north of Alai Creek (USGS Mesozoic loc. 10809). 

The same species ofSonn in ia has been found elsewhere 

in southern Alaska west of Cook Inlet and also in the 

Talkeetna Mountains above beds containing Parabigotites. West of Cook Inlet in the Tuxedni Bay area it has 

been collected in place from 100 to 230 ft (30.5 to 70 m) 

below the top of the Red Glacier Formation and is 

possibly represented 562 ft (172 m) below the top of the 

Red Glacier Formation (Imlay, 1964, p. Bll). In the 

Tuxedni Bay area it has also been reported from the 

upper fourth of the Fitz Creek Siltstone on the basis of
SYSTEMATIC DESCRIPTIONS 25

four specimens from two localities. Collections from 

one of these localities (USGS Mesozoic loc. 2999) are 

definitely float and from the other locality (USGS 

Mesozoic loc. 3000) include one specimen that appears 

to be worn and could be float (Imlay, 1964, p. B11,B13, 

B33). Evidently both stratigraphic and faunal evidence favors correlation of the highest beds in the 

Kialagvik Formation above the Parabigotites crassicostatus zonule with the highest few hundred feet of 

the Red Glacier Formation, which itself is correlated 

with the upper part of the zone of Otoites sa uzei (Imlay, 

1964, p. B7, B12; 1973, p. 10, 32).

The Kialagvik Formation is definitely represented 

in surface exposures at Wide Bay by one fairly well 

preserved specimen (see pi. 1, figs. 5, 6) of Hammatoceras of latest Toarcian age and by several float fragments of Enjcito ides of late early Bajocian age (USGS 

Mesozoic loc. 10806). Those genera, judging by the 

faunal sequence at Puale Bay, are separated stratigraphically by beds at least 300 ft (91 m) thick. Their 

association at USGS Mesozoic loc. 10806 could be 

related to the presence of a fault that is uplifted on its 

south side and has possibly brought rocks of late Toarcian age to the surface. Their association could also be 

related to erosion of beds of late Toarcian age at Wide 

Bay during times when sea level was appreciably 

lower than it is today, such as occurred in Alaska 

during major glacial advances (Karlstrom, 1964, pi. 7) 

of Late Tertiary time.

AMMONITE FAUNAL SETTING

The early and middle Bajocian ammonites found in 

southern Alaska belong mostly to 20 genera that are 

common in Europe and occur nearly worldwide, 

except possibly in the Arctic region. Ammonite genera or subgenera that are characteristic of the Pacific 

region include Alaskinia, Pseudotoites, Praeoppelia, 

Arkelloceras, Parabigotites, Pseudocidoceras, and probably Enjcitoides. The faunal succession in southern 

Alaska differs from that in Europe by the absence of 

any genera representing the Graphoceratidae.

GEOGRAPHIC DISTRIBUTION

Early and middle Bajocian ammonites have been 

found at many localities in southern Alaska, as described by the writer in 1964 and by Gerd Westermann 

in 1964 and 1969. Collections made subsequently in the 

Talkeetna and Wrangell Mountains have provided 

much new locality data, as shown in detail in table 2.

In contrast, the region west of Cook Inlet between 

Tuxedni Bay and Iniskin Bay has furnished very few 

fossil collections since the middle Bajocian ammonites 

of that area were described by the writer in 1964

(USGS Prof. Paper 418-B). As the locality descriptions concerning those ammonites are readily available to the reader (Imlay, 1964, p. B22-B29), only those 

localities in that area that have furnished early Bajocian ammonites are described herein (table 3, in part). 

The few ammonites found at Puale Bay are also listed 

in table 3. The many ammonites found near Wide Bay 

are listed in table 4. The geographic location and stratigraphic positions of all the fossil localities thus listed 

are described herein in table 5. The geographic postions of most of those localities are shown also, in figures 2-7.

SYSTEMATIC DESCRIPTIONS

Family Hildoceratidae Hyatt, 1867

Genus Pseudolioceras Buckman, 1889

Pseudolioceras cf. P. whiteavesi (White)

Plate 2, figure 11

cf. Ammonites (Amaltheus) u'hitcaresi White, 1889. U.S. Geol. Survey Bull. 51. p. 69, pi. 13, figs. 1-5.

cf.Pfteudolioeeras mclintocki irhiteavesi (White), Westermann, 1964, 

Bulls. American Paleontology, v. 47, no. 216, p. 421-425, pi. 68, 

fig. 2, pi. 69, figs. 1-6, pi. 70, figs. 1-4, pi. 71, figs. 1-2, text figs. 

30-31.

Two laterally crushed, weathered specimens resemble Pseudolioceras mclintocki whiteavesi (White) 

in shape, coiling, strongly falcoid ribs, a fairly high 

keel, and the presence in one specimen of a slightly 

raised umbilical edge.

Figured specimen. USNM 336000.

Occurrence. Red Glacier Formation, silty sandstone 

on shoreline overlying Lower Jurassic volcanic rocks 

of the Talkeetna Formation at USGS Mesozoic loc. 

29341. In SE cor. NE%SW% sec. 15, T. 1 N., R. 20 W., 

Kenai (A-8) quad., on southwest side of Tuxedni Bay, 

west of Cook Inlet.

Genus Asthenoceras Buckman, 1899

Asthenoceras cf. A. delicatum Imlay

Plate 1, figures 1, 2

cf. Asthenoceras sp. aff. A. nannodes Buckman, Westermann, 1969,

p. 61, pi. 14, figs. 1-7. 

cf. Asthenoceras delicatum Imlay, 1973, p. 55, pi. 3, figs. 1-32, pi. 4,

figs. 3-6.

The genus Asthenoceras is represented at USGS 

Mesozoic loc. 19862 in the Wide Bay area by four 

specimens that were collected at or near the place 

(WA10) where Asthenoceras was collected by Westermann (1969, p. 61, pi. 14, figs. 1-7). The specimens 

in hand, however, differ from those described by Westermann by having appreciably coarser ribbing that is 

comparable with that on some specimens of Asthenoceras delicatum Imlay (1973, pi. 3, figs. 1, 4-11) from 

Oregon.
26 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

TABLE 2. Geographic distribution of early and middle Bajocian ammonites in the Wrangell and Talkeetna Mountains

Genus and Species

Talkeetna Mountains

Nelchina area

23456 9 10 11 12 13 14 15 16

Boulder Creek 

area

17 18 19 20

Phylloceras cf. kunthi Neumayr ______________________ _ _ X

Partschiceras sp. . X

Calliphylloceras sp.

Holcophylloceras costisparsum Imlay X

sp. -_-.___.___._____.___ 

Lytoceras cf. L. eudisianum d'Orbigny _ _ X

sp. _________________________

Asthenoceras cf A. delicatum Imlay _ _ _ _

Pleydellia? sp. ____________________

Erycitoides howelli (White) ___________

Planammatoceras cf P. benneri (Hoffman)

Eudmetoceras (Euaptetoceras) amplectens Buckman X

Sonninia tuxedniensis Imlay _________________

cf. S. projectifer Buckman X

sp. juv _____________

(Sonninites) cf. S simulans Buckman _____ X

(Euhoploceras) bifurcata Westermann _____

(Alaskinia) cf. S. (A.) alaskensis Westermann

(A.) sp. ___._____..___._._.____.._

(Papilliceras) cf. S. (P.) espinazitenes (Tornquist) X 

Dorsetensia cf. D. adnata (Imlay) ______________

Witchelha sp. _____________________________

For.tanr.esia? sp. __________________________

Lissoceras cf. L. semicostatum Buckman _______________ _ _

. sp. ____________ X

Bradfordia costidensa Imlay

? caribouensis Imlay 

Otoites cf. O. pauper Westermann _____________________ X

Emileia? sp. ____________ X

Normannites uariabilis Imlay

Teloceras cf. T. blagdeni (Sowerby) X

Stephanoceras obesum Imlay _______________________ _ _ _X_

(S/cirrocereas) juhlei Imlay ________ X

(S.) nelchinanum Imlay _________

(S.) sp. __.____.___._____... 

Stemmatoceros cf. S. palliseri (McLearn)

sp. _______________________

Labyrinthoceras glabrum Imlay ______

Chondroceras allani (McLeam) _______

cf. C. allani (McLeam) _________

cf. C. marshalli (McLearn) _______

cf. C. co/netti (McLeam) ______________-----._--_

Parabigotites crassicostatus Imlay X X 

Leptosphinctes euolutus Imlay _
SYSTEMATIC DESCRIPTIONS 27

TABLE 3. Geographic distribution of some early and middle Bajocian ammonites west 

of Cook Inlet and northeast of Puale Bay on the Alaska Peninsula

[Number 21-23 are keyed to locality numbers on figure 12; number 24 to locality 24 on figure 13; and numbers 

25-30 to localities 25-30 on figure 14]

Genus and species

Tmetoceras scissum (Benecke)- ---------------

Erycitoides howelli (White) ---------.-______.

(Kiahguikes) cf. (K. ) kialaguikensis (White)

(K. ) leuis Westermann

(K. ) cf . K. spinatus Westermann . . . .

Dorsetensia? sp. -------------

Fontannnesia cf. F. carinata (Buckman) .___---._

Bradfordia costidensa Imlay.

West of 

Cook Inlet

Red Glacier 

Formation

21

CD 

CD 

CM 

, I 

CM

X

X

X

*t

CD 

CM 

i I 

CM

X

X

X

22

, i *f

CD 

(^ 

CM

X

23

in

CD 

CD 

"tf 

CM

X

24

21244F

X

Northeast of 

Puale Bay

Kialagvik 

Formation

25

ROC1472

X

26

mCD 

CMi H

CM

X

X

27

ROC1370

X

X

28

ROC1366

X

X

29

ROC1351

X

X

30

ROC 1356

X

X

Figured sped me ns. USNM 335956 and 335957.

Occurrence. Kialagvik Formation atUSGS Mesozoic loc. 19862 in SE cor. sec. 19, T. 33 S., R. 44 W., on 

the southeast side of Wide Bay, on the Alaska Peninsula.

Genus Tmetoceras Buckman, 1892 

Tmetoceras scissum (Benecke)

Plate 1, figures 18, 19

(For synonymy, see Westermann, 1964, Bulls. American Paleontology, v. 47, no. 216, p. 428, 429).

This species is represented northwest of Cook Inlet 

by 21 specimens, of which most are small and fragmented. In shape and ribbing they fit very well with a 

detailed description made by Westermann (1964, p. 

429-437, pi. 72, figs. la,b; 2a,b), and with a summary 

description by Imlay (1973, p. 59, pi. 2, figs. 1-6).

Hijpotypes.-USNM 335965 and 335966.

Occurrence. Red Glacier Formation, lower part, at 

USGS Mesozoic localities 21233, 21234, and 24335. 

Tmetoceras scissum (Benecke) is associated with Erycitoides howelli (White) at USGS Mesozoic Iocs. 21233 

and 21234, southwest of Tuxedni Bay on the west side 

of Cook Inlet.

Tmetoceras kirki flexicostatum Westermann

Plate 1, figures 21-23

Tmetoceras kirki flexicostatum Westerman, 1964, Bulls. American 

Paleontology, v. 47, no. 216, p. 440, pi. 72, figs. 8-10.

This subspecies is characterized by having fine, 

densely spaced, flexuous ribs, whereas the species T. 

kirki has fairly strong, moderately spaced, nearly

straight ribs, according to Westermann (1964, p. 

438-440).

Type. Hypotypes USNM 335968 and 335969.

Occurrence. Kialagvik Formation, at USGS Mesozoic loc. 21254 on tributary of Short Creek on northwest side of Wide Bay, in north-central part of sec. 28, 

T. 32 S., R. 44 W., Agashik (B-2) quad., Alaska.

Family Hammatoceratidae Buckman, 1887

Genus Hammatoceras Hyatt, 1867

Hammatoceras sp.

Plate 1, figures 5, 6

One ammonite collected from the Kialagvik Formation on the northwest side of Wide Bay at USGS 

esozoic loc. 10806 was identified by T. W. Stanton 

(Capps, 1921, p. 96) as "Ham matoceras" and compared 

with H. variabile (d'Orbigny). That species is now considered to be the genotype of Haugia, but the specimen 

from Wide Bay differs from Haugia by having (1) a 

stouter whorl section; (2) weaker tubercles that arise 

from the primary ribs at about one-fourth the height of 

the flanks; and (3) finer and denser secondary ribs on 

the middle and upper parts of the flanks. The ammonite from USGS Mesozoic loc. 10806 by contrast shows 

considerable resemblance to the genotype of Hammatoceras (Arkell and others, 1957, p. L267, fig. 

307c-e).

The occurrence of Hammatoceras at USGS Mesozoic loc. 10806 definitely favors an age as old as latest
28 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

TABLE 4. Geographic distribution of early and middle

[Numbers 31-69 are keyed to locality numbers on figure 15.

Genus and Species

Partschiceras ellipticum Westermann

Holcophylloceras costisparsum Imlay

Pseudolioceras whiteavesi (White)

maclintocki fastigatum Westermann _ _ . .,

costistriatum Westermann

Asthenoceras aff. A nannodes (Buckman)

A cf. delicatum Imlay

Tmetoceras scissum (Benecke)

kirki Westermann

kirki flexicostatum Westermann _ _ ...

(Tmetoites) tenue Westermann

Hammatoceras ? sp.

Planammatoceras aff P benneri (Hoffman)

Eudmetoceras cf. £. eudmetum jaworskii Westermann _._._.....

(Euaptetoceras) amplectens (Buckman)

(£ ) k/imakomo/Ki/um discoidale Westermann

(£ ) aff £ (£. ) nucleospinosum Westermann

Erydtes im/ayi Westermann _...__._-.......-..-.-.-

Erycitoides howelli (White) ...

cf £. howelli (White) . .

pro/undus Westermann

teres Westermann

paucispinosus Westermann .

(Kia/aguikes) kia/aguikensis (White)

(K ) spinatus Westermann

(K. ) /euis Westermann

Abbasites p/afystomus Westermann _ _ .

(Papi//iceras) cf. S. (P.) arenata (Quenstedt) .. ...

(Euhop/oceras) bifurcata Westermann

(Alaskinia) alaskensis Westermann

Witchellia sutneroides Westermann

cf. sutneroides Westermann

Dorsetensia adnata (Imlay) _...._......._......_....___..

Fonfannesia cf. F. intermedia Imlay .......

Pelekodites cf. P. pe/ekus Buckman

Hebetoxyites aff. H. hebes Buckman

Bradfordia constidensa Imlay

Praeoppelia oppeliformis Westermann

Docidoceras aff. D. longahum (Vacek)

(Pseudocidoceras) luidebayense Westermann

(P.) camachoi Westermann

(P. ) cf (P. ) camachoi Westermann

?(P.) paucinodosum Westermann

Pseudotoites cf. P argentinus Arkell

cf. P. transat/anticus (Tornquist)

Otoites sp

Arke/toceras sp.

Parabigotites kia/aguikensis (Imlay)

crassicostatus Imlay

cf P. crassicostatus Imlay

Kialagvik Formation on northwest side of Wide Bay

31

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SYSTEMATIC DESCRIPTIONS 29

Bajocian ammonites near Wide Bay on the Alaska Peninsula

Higher numbers are USGS Mesozoic locality numbers]

Kialagvik Formation on 

northwest side of Wide Bay

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30 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA 

TABLE 5. Deno'/i>ti<n>n of mid file and loirer Bojocicni fonxil localities in Kouthfrn Alaska

Locality USGS Mesozoic Collector's 

No. locality field No.

13

14

14

14

15

15

16

17

17

28682

27577

24113

31728

25945

26723

25345

25346

24176

25946

24137

62AM K53

52AGz-85

79AGz-98 ... 

55AGz-245a 

57AGz43N . 

54AFy28 .... 

54AFy29 ..... 

52AHr51 ..... 

55AGz309 ... 

52AGz284 ...

10

10

11 ....

1?!

.... 24215 ....

.... 25942 .....

.... 24134 .....

.... 24235 .....

... 52AGzl82 ............

... 55AGzl63 ............

... 52AGz275 ............

... 52AGz240 ............

24149

8585 .

24120

24220

52AGz233

13AM36 .. 

52AGzl98 

52AGz215

3696 .......... 6AK88A

3697 .

30600

30280

30281

6AK88B .......

74APr60b .....

72AD7-11#6 

72AD7-12 .....

R. W. Imlay, 1962. Wrangell Mountains. McCarthy (C-5) quad. Near creek in center SE' 4

NWJ 4 sec. 20, T. 3 S., R. 16 E., Nizina Mountain Formation, mostly float. Probably from

the basal part of the formation. 

Western Gulf Oil Co., 1959. Talkeetna Mountains (A-l) quad., near Crooked Creek south of

Nelchina, lat. 62°02'00" N., long. 147°18'00" W., Tuxedni Group, lower part (probably

siltstone). 

Arthur Grantz, Richard Hoare, and R. W. Imlay. 1952. Talkeetna Mountains (A-l) quad.

From a landslide scar 1.63 mi (2.6 km) north of the mouth of Albert Creek. Tuxedni

Group 200-250 ft (61-76 m) above base. 

Arthur Grantz, 1979. Talkeetna Mountains (A-l) quad., lat. 62°01'4" N., long. 147°17'36" W.,

Tuxedni Group (same locality as 24113). 

Arthur Grantz, 1955. Talkeetna Mountains (A-l) quad., lat. 62°02'28" N.. long. 147°22'59" W.,

Tuxedni Group, upper half of lower sandstone. 

Arthur Grantz, 1957. Talkeetna Mountains (A-l) quad., lat. 62°02'00" N., long. 147°25'15" W.,

Tuxedni Group, upper half of basal sandstone. 

L. F. Fay, 1954. Talkeetna Mountains (A-2) quad, lat. 62°00'46" N., long. 147°34'02V/' W,

Tuxedni Group, upper siltstone. 

L. F. Fay, 1954. Talkeetna Mountains (A-2) quad., lat. 62°00'41" N., long. 147°34'16 V W.,

Tuxedni Group, upper siltstone. 

Richard Hoare, 1952. Anchorage (D-2) quad. Pass Creek, 0.35 mi (0.56 km) above its mouth.

Tuxedni Group, basal sandstone, 100-200 ft (30-61 m) above base. 

Arthur Grantz and W. H. Condon, 1955. Anchorage (D-2) quad, lat. 61°57'47" N, long.

147°24'21" W, Tuxedni Group, 200-300 ft (61-91 m) above base. 

Arthur Grantz, R. W. Imlay, and D. Hoare, 1952. Anchorage (D-2) quad, 0.53 mi (0.9 km) S.

74 1 :, 0 E. of mouth of Pass Creek and 0.16 km south of USGS Mesozoic loc. 25946. Tuxedni

Group, basal sandstone 200-300 ft (61-91 m) above base. 

Richard Hoare and Arthur Grantz, 1952. Anchorage (D-2) quad, Alfred Creek, 0.8 mi (1.3 km)

east of Papoose Creek. Tuxedni Group, upper siltstone. 

Arthur Grantz and W. H. Condon, 1955. Anchorage (D-2) quad, lat. 61°57'09" N, long.

147°27'56" W., Tuxedni Group, upper siltstone. 

Arthur Grantz, Richard Hoare, and R. W. Imlay, 1952. Anchorage (D-2) quad, 2.63 mi (4.2

km) N. 51 1/;, 0 E. of mouth of Sheep Creek. Tuxedni Group, base of upper siltstone. 

Arthur Grants, Richard Hoare, and R. W. Imlay, 1952. Anchorage (D-2) quad. Sheep Creek,

2.20 mi (3.32 km) N. 16 1 ; 0 E. of its mouth. Tuxedni Group, float from the lower 30.5 m of

the basal sandstone. 

Arthur Grantz, Richard Hoare, and R. W. Imlay, 1952. Anchorage (D-2) quad, 3 mi (4.8 km)

N. 9° E. of the mouth of Sheep Creek on a small west tributary. Tuxedni Group, float from

the lower 100 ft (30.5 m) of the basal sandstone. 

G. C. Martin, 1913. Anchorage (D-2) quad, north bank of Caribou Creek 0.75 mi (1.2 km) east

of mouth of Billy Creek. Tuxedni Group, upper siltstone. 

Arthur Grantz, Richard Hoare, and R. W. Imlay, 1952. Anchorage (D-3) quad. Caribou Creek

0.62 mi (1 km) east of Billy Creek. Tuxedni Group, upper siltstone. 

Arthur Grantz, Richard Hoare. and R. W. Imlay, 1952. Anchorage (D-2) quad, north side of

Caribou Creek, 0.73 mi (1.17 km) east of mouth of Billy Creek. Tuxedni Group, upper siltstone. 

Adolph Knopf, 1906. Anchorage (D-3) quad, at altitude of 4,050 ft, on tributary of Caribou

Creek that joins main creek from south 0.25 mi (0.40 km) above mouth of Billy Creek.

Tuxedni Group, upper siltstone.

Adolph Knopf, 1906. Anchorage (D-3) quad, boulder in stream bed at same location as Mesozoic loc. 3696. 

George Pflaker, 1974. Anchorage (D-3) quad, 1.5 mi N. 45° E. of VABM Chitna in sec. 4. T. 21

N, R. 9 E, elev. 5,250 ft. Tuxedni Group, dark shale that contains a few sandstone beds

and is intruded by a basaltic dike. 

R. L. Detterman, R. W. Imlay, and Don Hartman, 1972. Anchorage (D-3) quad. From southern

part of divide north of peak (elev. 5,900 ft) north of Boulder Creek, 1.2 mi (1.9 km) S. 35°

W. of VABM Snag. SEV4 sec. 26, T. 22 N, R. 7 E, Tuxedni Group, upper part, from lower

75 ft (23 m) of 175 ft (53 m) of brown-to-gray siltstone that underlies 80 ft (24 m) of volcanic graywacke. 

R. L. Detterman, R. W. Imlay, and Don Hartman, 1972. Anchorage (D-3) quad, 1.1 mi (1.8 km)

S. 38° W. of VABM Snag near center of sec. 26, T. 22 N, R. 7 E, Tuxedni Group, sandstone, grit, and conglomerate with siltstone interbeds about 250-300 ft (76-91 m) below

siltstone listed under USGS Mesozoic loc. 30280.
SYSTEMATIC DESCRIPTIONS 31

TABLE 5. Description* of middle and loirer Bajocian fossil localities in southern Alaska Confirmed

Locality USGS Mesozoic Collector's 

No. locality field No. Collector, year of collection, description of locality, and stratigraphic assignment

18 ........ 30582 ........ 74AD7-95

26

32

19 ........ 8567 .......... 113AM16 ....

20 ........ 30594 ........ 74ADT130A

21 ........ 21233 48AI77

21 ........ 21234 ........ 48AI78

22 ........ 29341 ........ Ken 72

23 ........ 24335 ........ 52AJU516A

24 ........ 21244F ...... 48AI32

25 ........ ROC1472. 1962

21235 ........ 48AI110

27 ........ ROC1370

28 ....... ROC1366

29 ........ ROC1351

30 ........ ROC1356.. ......................

31 ........ 19766 ........ 44AKmF36

31 ........ 21246 ........ 48AI95

19757 ........ 44AKmF23

32 ........ 19767 ........ 44AKm37

33 ........ 21255 ........ 48AI89 ...

R. L. Detterman, 1974. Anchorage (D-3) quad., on ridge south of tributary of Boulder Creek in 

sec. 4, T. 21 N.. R. 7 E., 0.88 mi (1.4 km) S. 40° E. of VABM Suicide. Tuxedni Group, near 

middle, from interbedded brown sandstone, siltstone, and siltstone and shale containing 

limestone concretions.

G. C. Martin, R. M. Overbeck, and J. B. Mertie, Jr., 1913. Anchorage (D-4) quad., in northcentral part of NE 1/, sec. 19, T. 21 N., R. 7 D., Tuxedni Group.

R. L. Detterman, 1974. Anchorage (D-4) quad. SEV, NE' 4 sec. 20, T. 21 N., R. 7 E., 2.8 mi (4.48 

km) N. 73° E. of VABM Pudding, elev. 5,400 ft on ridge west of Boulder Creek. Tuxedni 

Group, high in sequence of dark-greenish sandstone bearing volcanic clasts.

R. W. Imlay and D. J. Miller, 1948. South side of Tuxedni Bay. West central part of NWV4 

SW/4 sec. 15, T. 1 N., R. 21 W., Kenai (A-8) quad., on creek entering Tuxedni Bay from 

south 2.25 mi (3.6 km) N. 77° W. of Fossil Point. Red Glacier Formation, 380-480 ft 

(116-146 m) above base and 1,500 ft (457 m) below top in sandy siltstone interbedded with 

sandstone. Location is indicated by number (830) on pi. 3 of U.S. Geol. Survey Prof. Paper 

512.

R. W. Imlay and D. J. Miller, 1948. South side of Tuxedni Bay. Float from same place and 

probably from same bed as USGS Mesozoic loc. 21233. Red Glacier Formation.

British Petroleum Exploration Co., 1962. South side of Tuxedni Bay, SE cor. NE 1/!, SW1 ^ sec. 

15, T. 1 N., R. 20 W., Kenai (A-8) quad. Red Glacier Formation, first exposure of silty 

sandstone overlying Lower Jurassic volcanic rocks to the northwest.

R. W. Imlay, 1952. On low divide north of Red Glacier, 2.5 mi (4 km) west of Red Creek and 

5.2 mi (8.3 km) N. 5° W. of Blue Lake. North-central part NE^ NWH sec. 33, T. 1 S., R. 21 

W., Kenai (A-8) quad. Red Glacier Formation, lower siltstone member, about 900-1,000 ft 

(274-335 m) above base and 3,400-3,600 ft (1,036-1,097 m) below top. Location is indicated 

by number (X40) on pi. 3 of U.S. Geol. Survey Prof. Paper 512.

R. W. Imlay, J. K. Hartsock. and D. J. Miller, 1948. By Iniskin Peninsula on Fitz Creek near 

Tonnie Creek. Iniskin Bay Assoc. well 1 in SE 1/, sec. 8, T. 5 S., R. 23 W., Seward Meridian. 

Red Glacier Formation, hard gray-to-black siltstone, at 5,495-5,515 ft (2,225-2,231 m) 

below top. Detterman and Hartsock, 1966, p. 72, 73, table 4 on p. 24, and pi. 4; location is 

indicated by number (X41) on pi. 3.

W. T. Rothwell and associates of the Richfield Oil Co. Collected about 2,800 ft (853 m) N. 50° 

W. of VABM 119 Bay on northeast side of Puale Bay in the Karluk (C-4 and C-5) quad., on 

the Alaska Peninsula. Kialagvik Formation, near top, and about 500 ft (152 m) above a 

massive conglomerate.

Ralph Imlay, 1948. Sea cliff on northeast side of Puale Bay, 2.24 mi (3.58 km) N. 19° W. of 

Cape Kekurnoi on the Alaska Peninsula. Kialagvik Formation, from a concretion in siltstone about 200 ft (61 m) below base of massive conglomerate.

Richfield Oil Co., 1962. Southeast shore of Puale Bay, about 2 mi (3.2 km) N. 18%° W. of Cape 

Kekurnoi on the Alaska Peninsula. Kialagvik Formation, about 100 ft (30.5 m) below top 

of ashy beds and about 800 ft (244 m) below the base of a massive conglomerate.

Geologists of the Richfield Oil Co., 1962. Northeast shore of Puale Bay, about 650 ft (198 m) S. 

25° E. of VABM 119 Bay. Kialagvik Formation, about 40 ft (12 m) below ROC loc. 1370.

Geologists of the Richfield Oil Co., 1962. Northeast shore of Puale Bay, about 1,250 ft (381 m) 

S. 25° E. of VABM 119 Bay. Kialagvik Formation, about 900-950 ft (274-290 m) below 

massive conglomerate.

Geologists of the Richfield Oil Co., 1962. Northeast side of Puale Bay, near locality ROC1351.

L. B. Kellum. 1944, Float from base of cliffs. About 14 mile south of mouth of Pass Creek and 

3.6 mi (6 km) N. 45° W. of west end of Hartman Island. Kialagvik Formation, about 480 ft 

(146 m) below top.

R. W. Imlay and D. J. Miller, 1948. SEV4 NWV4 of sec. 24, T. 32 S., R. 44 W., sea cliff along 

beach 3.1 mi (5 km) N. 50° W. of west end of Hartman Island. About 0.2 mi (0.32 km) 

northeastward along a cliff composed of sandstone and siltstone. Kialagvik Formation, 

about 800 ft (244 m) below top.

L. B. Kellum and assistants, 1944. Float at base of sea cliff between Pass Creek and Short 

Creek northeast of small waterfall and 0.5 mi (0.2 km) southwest of Pass Creek. SE 1/; sec. 

23, T. 32 S., R. 44 W. Kialagvik Formation, 880-995 ft (268-303.5 m) below top.

L. R. Kellum, 1944. SE 1 ! sec. 23, T. 32 S., R. 44 W., Kialagvik Formation, about 1,050 ft (320 

m) below top.

R. W. Imlay and D. F. Miller, 1948. Southwest bank of tributaries entering Short Creek about 

1 mi (1.6 km) northwest of beach. North-central part of SWV4 sec. 28, T. 32 S., R. 44 W. 

Kialagvik Formation, from gray siltstone about 400 ft (122 m) below top.
32 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

TABLE 5. DeitcrijrfioHN of middle atnl loircr Bajocifni foxxil localitii'x in southern Al«xk« Continued

Locality USGS Mesozoic Collector's

No. locality field No. Collector, year of collection, description of locality, and stratigraphic assignment

33 ........ 21257 ........ 48AI91

33 ........ .................... L1038

36

36

36

37

37

38

38

38

39

40

41

42

42

42

42

43

43

21254

31978

31979

19748 .

21245

19747

21250

21248

21247

19776

11352

19773

19775

21258

31987

10806

33 ........ 31976 ........ 80ACel99B

34 ........ 21256 ........ 48AI90 .......

35 ........ 19786 ........ 44AKMF56

36 ........ 19755 ........ 44AKMF21

48AI109

80ACe200

80A ...............

44AKmFl3

A454

48AI86

44AKmF12 

48AI88 .......

48AI108 ..... 

48AI107 .....

44AKmF46 

15 .................

44AKmF43 

44AKmF45 

48AI96 .......

8ACe202A . 

1-107 ..........

R. W. Imlay and D. J. Miller, 1948. North-central part of SWV, sec. 28, T. 32 S., R. 44 W.

Kialagvik Formation, from base of silty sandstone, overlying sandstone whose top is 400 ft

(122 m) below top of formation. 

Geologists of the Shell Oil Co. On the tributary entering Short Creek from the north in the

SW'.4 sec. 28, T. 32 S, R. 44 W. Kialagvik Formation, from lower third of 490 ft (150 m) of

silty shale. 

Jim Case, 1980. North-central part of SW1 , sec. 28, T. 32 S., R. 44 W., 1 mi (0.6 km) N. 58° W.

of Tri. Station Creek. Kialagvik Formation, sandstone and limestone beds. 

R. W. Imlay, 1948. On ridge south of tributary entering Short Creek, 4.6 mi N. 75 1 '2 ° W. of west

end of Hartman Island. SE^ SWV4 sec. 28, T. 32 S., R. 44 W. Kialagvik Formation, 320 ft

(98 m) below top. 

L. B. Kellum, 1944. NWV4 NE 1 ! sec. 3, T. 32 S., R. 44 W., 5.75 mi (9.2 km) N. 76° W. of west

end of Hartman Island. In canyon of Short Creek, 0.5 mi (0.8 km) above first rapids.

Kialagvik Formation, 100 ft (30 m) below top in a shale bed interbedded with sandstone. 

L. B. Kellum, 1944. North-central part of sec. 33, T. 32 S., R. 44 W., about 100 ft (0.2 km) north

of intersection of stream entering Short Creek from the north and 0.75 mi downstream

from first falls. Kialagvik Formation, 603 ft (184 m) below top in 2 ft (0.6 m) of shabby

sandstone 30 ft (9 m) below top of falls.

R. W. Imlay, 1948. North-central part of sec. 33, T. 37 S., R. 44 W. Above the falls on a tributary entering Short Creek 1 mi (1.6 km) northwest of the beach. Kialagvik Formation,

about 600 ft (183 m) below top in gray calcareous sandstone. 

Jim Case, 1980. North-central part of sec. 33. T. 32 S., R. 44 W., 0.67 mi (1 km) N. 84° W. of

Tri. Station Creek. Kialagvik Formation.

Jim Case, 1980. Location is the same as Mesozoic loc. 31978. Kialagvik Formation. 

L. B. Kellum, 1944. SW1,^ NEV4 sec. 33, T. 32 S., R. 44 W., on south side of Short Creek about

1.5 mi (2.4 km) from its mouth and 750 ft (229 m) below the first rapids. Kialagvik Formation, 800 ft (244 m) below top, at top of a coarse conglomerate. 

Shell Oil Co., 1953. On Short Creek probably at same location as USGS Mesozoic loc. 19748

(see map by Westermann, 1964, text-fig. 2, opposite p. 332). Kialagvik Formation, about

160 m below top. 

R. W. Imlay and D. J. Miller, 1948. South-central part of NEV4 sec. 33, T. 32 S., R. 44 W., on

south side of Short Creek. Kialagvik Formation, about 1,050 ft (317 m) below top, fossils

from a gray sandstone bed, dark-gray siltstone. 

L. B. Kellum, 1944. South side of Short Creek at same location as USGS Mesozoic loc. 21245.

Kialagvik Formation, 317 m below top. 

R. W. Imlay and D. J. Miller, 1948. Short Creek at head of first falls near USGS Mesozoic loc.

21245. Kialagvik Formation, 600 ft (183 m) below top, gray sandstone at top of a sandstone

sequence. 

R. W. Imlay and D. J. Miller, 1949. Central part of NWV4 sec. 34, T. 32 S., R. 44 W., on south

side of Short Creek about 0.5 mi (0.8 km) from beach. Kialagvik Formation, about 1,700 ft

(518 m) below top, gray siltstone. 

R. W. Imlay and D. J. Miller, 1948. SE corner of NEV4 sec. 34, T. 32 S., R. 44 W., 0.2 mi (0.3

km) from beach. Kialagvik Formation, about 2,000 ft (610 m) below top, dark-gray siltstone. 

L. B. Kellum, 1944. NWJ'4 NE^ sec. 3, T. 33 S., R. 45 W., on northeast side of Anderson Creek

at base of a bluff. Kialagvik Formation, about 200 ft (62 m) below top, shaly sandstone. 

W. R. Smith, 1922. North-central part of SW1 ^ sec. 2, T. 32 S., R. 45 W., on high knob on north

side of Anderson Creek, about 1 mi (1.6 km) from Wide Bay. Kialagvik Formation. 

L. B. Kellum, 1944. Same location as USGS Mesozoic loc. 11352. Kialagvik Formation, about

220 ft (67m (below top. 

L. B. Kellum, 1944. Same location as USGS Mesozoic loc. 11352. Kialagvik Formation, about

300 ft (91 m) below top, shaly sandstone near base of a cliff. 

R. W. Imlay and D. J. Miller, 1948. Same location as USGS Mesozoic loc. 11352. Kialagvik

Formation, about 225 ft (69 m) below top. 

Terry Poulton, 1980. South-central part of NE 1/, sec. 2, T. 33 S., R. 45 W., 1.95 mi (3.2 km) N.

45° E. of Triangulation Station Spit in Ugashik B-2 quad. Kialagvik Formation. 

S. R. Capps, 1921. Probably same location as USGS Mesozoic loc. 31987 and about 1 mi (1.6

km) north-northwest of mouth of "Anderson" Creek. Kialagvik Formation (partly float

specimens collected at base of bluff on west side of a spit).
SYSTEMATIC DESCRIPTIONS 33

TABLE 5. Descriptions of middle and lotrer Bajocian fossil localities in southern Alaska Continued

Locality USGS Mesozoic 

No. locality

Collector's 

field No. Collector, year of collection, description of locality, and stratigraphic assignment

44

45

46

47

48

49

50

50

51

55

55

63

63

21253

31982

31980

10809

31955

31956

31951

31949

31947

12404

19884

31969

32287

48AI105

80ACe202 ... 

80ACe201 ... 

1-113 ..........

80ACel63B 

80ACel64 ... 

80ACel63 ...

80ACel62 

80ACel61

52 ....

52 ....

53 ....

54 ....

54 ....

55 ....

.... 31957 .....

.... 31958 .....

... 19926 ....

.... 19742 ....

.... 19796 .....

.... 11349 ....

.... 80ACel74 ... ........

.... 80ACel74A ........

.... 45AKmF116 ......

.... 44AKmF3

.... 44AKmF66 ........

... F13 ......................

F26 ..............

45AKmF74

56 ...

57 ....

58 ....

59 ....

.... .................... L556 ......................

... .................... L555 ......................

.... 19798 ........ 44AKmF68 ........

.... 19836 ........ 45AKmF29 ........

59 ....

59 ....

60 ....

61

62 ....

.... 19840 ....

.... 19850 .....

.... 19852 ....

.... 19811 .....

... 45AKmF33 ........

... 45AKmF43 ........

.... 45AKmF45 ........

.... L154 ................ ...

.... 45AKmF4

80ACel77A

81JCH11

R. W. Imlay and D. J. Miller, 1948. Sea cliff in west-central part of NWV4 sec. 11, T. 33 S., R.

45 W., about 1 mi (1.7 km) northeast of Triangulation Station Spit. Kialagvik Formation,

probably about 500 ft (152 m) below top of formation. 

Jim Case, 1980. NW\4 SE 1 :, sec. 10, T. 33 S., R. 45 W., 0.57 mi (0.9 km) N. 30° E. of Triangulation Station Spit. Kialagvik Formation, calcareous sandstone.

Jim Case, 1980. On beach in NWV4 sec. 15., T. 33 S., R. 45 W., 0.18 mi (0.3 km) N. 84 W. of Triangulation Station Spit in Ugashik B-2 quad. Kialagvik Formation, conglomerate. 

S. R. Capps, 1921. North-central part of sec. 17, T. 33 S., R. 45 W., 1.5 mi (2.4 km) from mouth

of creek that enters Wide Bay from the southwest. Kialagvik Formation, upper part. 

Jim Case, 1980. NE corner of sec. 16, T. 33 S., R. 45 W., 1.4 mi (2.3 km) S. 77° W. of Triangulation Station Spit in Ugashik B-2 quad. Kialagvik Formation, brownish mudstone. 

Jim Case, 1980. East-central part of NW1/, sec. 16, T. 33 S., R. 45 W., 1.1 mi (1.8 km) S. 73° W.

of Triangulation Station Spit. Kialagvik Formation, float block of massive sandstone. 

Jim Case, 1980. Near beach in SE 1/, NW'4 sec. 16, T. 33 S., R. 45 W., 1.3 mi (2.1 km) S. 73° W.

of Triangulation Station Spit. Kialagvik Formation, calcareous sandstone concretions. 

Jim Case, 1980. Same data as for USGS Mesozoic loc. 31951. Kialagvik Formation, float. 

Jim Case, 1980. SEV4 NE^ sec. 17, T. 33 S., R. 45 W., 1.5 mi (2.5 km) S. 65° W. of Triangulation

Station Spit. Kialagvik Formation, pebbly sandstone. 

Jim Case, 1980. West-central part of NEV4 sec. 19, T. 33 S., R. 45 W., 2.5 mi (4 km) N. 68° E. of

Triangulation Station Alai in Ugashik R-2 quad. Kialagvik Formation, massive sandstone. 

Jim Case, 1980. Same locality as USGS Mesozoic loc. 31957. Kialagvik Formation, massive

sandstone. 

L. B. Kellum, 1945. Cliff east of Kialagvik Creek below a glacier. West-central part of NW1/;

sec. 4, T. 34 S., R. 45 W. Kialagvik Formation. 

L. B. Kellum, 1944. Southeast shore of Wide Bay in south-central part of sec. 33, T. 33 S., R. 34

W. Kialagvik Formation, float blocks of sandstone. 

L. B. Kellum, 1944. Southeast shore of Wide Bay at same location as USGS Mesozoic loc.

19742. Kialagvik Formation, float from a bluff. 

W. R. Smith, 1922. Near beach on south side of small creek in north-central part of SE 1^ of sec.

33, T. 33 S., R. 45 W. Kialagvik Formation.

W. R. Smith, 1924. Same location as USGS Mesozoic loc. 11349. Kialagvik Formation. 

L. B. Kellum, 1945. Sea cliff 0.25 mi (0.4 km) southeast from SW corner of Wide Bay at same

location as USGS Mesozoic loc. 11349. Kialagvik Formation, an Inoceramus bed 50 ft (15

m) below top of cliff. 

Shell Oil Co. 0.25 mi (0.3 km) southwest of L555 and 15 m lower stratigraphically. SW'4 NEV4

sec. 34, T. 33 S., R. 45 W. 

Shell Oil Co. NEV4 sec. 34, T. 33 S., R. 45 W., 0.25 mi (0.3 km) northeast of Shell loc. L556.

Kialagvik Formation.

L. B. Kellum, 1944. On beach in northwest corner of sec. 35, T. 33 S., R. 45 W. Kialagvik Formation, float from sea cliffs.

L. B. Kellum, 1945. Spur west of most easterly of two large streams on southeast shore. Southcentral part of NWV, sec. 35, T. 33 S., R. 45 W. Elev. 475 ft. Kialagvik Formation, 192 ft

(58 m) below top of formation in shaly, crumbly sandstone.

L. B. Kellum, 1945. Same location as USGS Mesozoic loc. 19836. Elev. 636 ft (194 m). Kialagvik Formation, 130 ft (40 m) below top of formation.

L. B. Kellum, 1945. Same location as USGS Mesozoic loc. 19836. Elev. 600 ft (183 m). Kialagvik Formation, float collected in a gully. 

L. B. Kellum, 1945. In east-central part of NWV4 sec. 35, T. 33 S., R. 45 W. Elev. 736 ft (224 m).

Kialagvik Formation, talus. 

Shell Oil Co. On shore in west-central part of SE 1 /, sec. 26, T. 33 S., R. 45 W., about 3 mi (5 km)

east of mouth of Kialagvik Creek, 60 m below top. 

L. B. Kellum, 1945. NWV4 SE^ sec. 25, T. 33 S., R. 45 W., about 3,000 ft (0.9 km) east of mouth

of more easterly of two large creeks. Kialagvik Formation, 45 ft (13.7 m) below top in a

shaly sandstone bed, at elev. of 134 ft (41 m). 

Jim Case, 1980. NEV4 sec. 25, T. 33 S., R. 45 W., 3.25 mi (5.2 km) S. 50° E. of Triangulation

Station Spit. Kialagvik Formation, mudstone about 25 ft (3.6 m) below the cliff-forming

sandstone. 

J. H. Callomon, 1981. Same location as USGS Mesozoic loc. 31969. 1.7 mi (2.7 km) N. 15° W. of

Triangulation Station Wide, 60 m above a sandstone cliff. Kialagvik Formation, 198 ft (60

m) above a sandstone cliff.
34 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

TABLE 5. Dexcn'otionn of middle and loin r Btijocioii foxm'1 localities in xontherti Alaxkn Continued

Locality USGS Mesozoic Collector's 

No. locality field No.

63

64

64

64

65

65

65

65

65

66

32290

19801

815HC14 . 

44Akm72

WA5 ..... ..

WAS .. ....

19863

19822

19823

19824

19825

31965

45AKmF15

45AKmF16 

45AKmF17 

45AKmF18 

80ACel75A

66 .... 

66 ...

66 ....

67 ....

.... 31966 .... 

.... 32292 ....

.... 32291 ....

.... 19869 ....

... 80ACel75B ....... 

.... 81JHC16 ....... ...

... 81JHC15 ..............

... 45AKmF62 .......

67 ........ .................... WA10

67 19862 45AKmF55

67 ....

67 ....

67 ....

67 ....

67 ....

68 ....

.... 32293 ....

.... 32295 ....

.... 32296 ....

.... 19876 ....

.... 19877 ....

.... 21251 ....

.... 81JHC17 ..............

... 81JHC19 .

... 81JHC20 ..............

... 45AKmF69 ........

.... 45AKmF70 ........

... 48AI103 ..............

68

69

21252

12405

48AI104 

24ASF27

J. H. Callomon, 1981. Same location and formation as USGS Mesozoic loc. 32289, but 201 ft 

(63.5 m) above the sandstone cliff.

S. N. Davies, 1944. NW corner sec. 30. T. 33 S., R. 44 W.. on southeast side of Wide Bay, about 

1 mi (1.6 km) east of Preston Creek. Kialagvik Formation, from base of a shale unit that 

bears limestone concretions and underlies an unconformity.

G. E. G. Westermann. 1944. About 1.1 mi (1.75 km) east of Preston Creek. Kialagvik Formation, talus from greywacke and some silty shale.

G. E. G. Westermann, 1944. Same location as USGS Mesozoic loc. 19801, about 1.1 mi (1.75 

km) east of Preston Creek. Kialagvik Formation, from uppermost and lowermost massive 

greywacke overlain by shale and underlain by sandstone and siltstone.

L. B. Kellum, 1945. About 6,850 ft (2.1 km) east of Preston Creek in north-central part of NW1,., 

sec. 30, T. 33 S., R. 44 W. Kialagvik Formation, float about 62 ft (19 m) below top at elevation of 140 ft (43 m).

L. B. Kellum, 1945. North-central part of NW' 4 sec. 30, T. 33 S., R. 44 W., about 5,700 ft (1,737 

m) northeast of Preston Creek at elevation of 170 ft (52 m). Kialagvik Formation, fossils 

found in float 30 ft (9.1 m) below top.

L. B. Kellum, 1945. Same location as USGS Mesozoic loc. 19822, at elevation of 351 ft (107 m). 

Kialagvik Formation, 15 ft (4.7 m) below top.

L. B. Kellum, 1945. Same location as USGS Mesozoic loc. 19822, at elevation of 371 ft (113 m). 

Kialagvik Formation, 5 ft (1.5 m) below top.

L. B. Kellum, 1945. Same location as USGS Mesozoic loc. 19822, at elevation of 385 ft (117 m). 

Kialagvik Formation, 25 ft (7.6 m) below top.

Jim Case, 1980. NE 1 , NWJ 4 sec. 30, T. 33 S., R. 44 W., 1.75 mi (2.8 km) due north of Triangulation Station Wide. Kialagvik Formation, shale containing limestone concretions about 75 

ft (15.23 m) above lowest sandstone.

Jim Case, 1980, Same location as USGS Mesozoic loc. 31965, but 20 ft (6 m) higher in the 

Kialagvik Formation.

J. H. Callomon, 1981. Same location as USGS Mesozoic loc. 31965. 1.78 mi (2.85 km) due north 

of Triangulation Station Wide. Kialagvik Formation, 30-35 ft (9-11.5 m) above the beach.

J. H. Callomon, 1981. Same location as USGS Mesozoic loc. 31965. Collected 10 ft (3 m) above 

beach. Kialagvik Formation.

L. B. Kellum, 1945. Same location as USGS Mesozoic loc. 31965, but 1.4 mi (2.3 km) east of 

Preston Creek in a gully near shoreline. Kialagvik Formation, 480 ft (145 m) below top, in 

dark-grey concretionary shale interbedded with some thin beds of grey limestone.

G.E.G. Westermann, 1944. NW corner of NE 1 ^ of sec. 30, T. 33 S., R. 44 W., 1.5 mi (2.45-2.55 

km) east of Preston Creek. Kialagvik Formation, from 69 ft (21 m) of dark-grey concretionary shale exposed in sea cliff on both sides of a small stream.

L. B. Kellum, 1945. Same sea cliffs at same place as listed in locality WA10. Kialagvik Formation, 143 ft (43 m) below top and 23 ft (9 m) above beach in shale bearing sandstone stringers above massive sandstone.

J. H. Callomon, 1981. Same location as in locality WA10. 1.8 mi (3 km) N. 3° E. of Triangulation Station Wide. Kialagvik Formation, about 33 ft (10 m) above beach.

J. H. Callomon, 1981. Same location as USGS Mesozoic loc. WA10 and 32293. Kialagvik Formation, 82 ft (25 m) above beach.

J. H. Callomon, 1981. Same location as USGS Mesozoic loc. 32293. Kialagvik Formation, 134 ft 

(40 m) above beach.

L. B. Kellum, 1945. NW corner NE^ sec. 30, T. 33 S., R. 44 W., near boundary with sec. 19. 

7,600 ft (2.3 km) east of Preston Creek. Kialagvik Formation, at elevation of 120 ft (37 m).

L. B. Kellum, 1945. Same location as USGS Mesozoic loc. 19876. Kialagvik Formation, at elevation of 150 ft (45.7 m).

R. W. Imlay and D. J. Miller, 1948. Sea cliff 1.7 mi (2.85 km) east of Preston Creek in NE 1/, sec. 

30, T. 33 S., R. 44 W., near boundary with sec. 19. Kialagvik Formation, about 500 ft (150 

m) below top, in grey siltstone.

R. W. Imlay and D. J. Miller, 1948. Same location as USGS Mesozoic loc. 21251. Kialagvik 

Formation, 25 ft (7.6 m) above a massive sandstone. Probably lower than loc. 21251.

W. R. Smith, 1924. Near center of sec. 20, T. 33 S., R. 44 W., on southeast side of Wide Bay, 

about 1.5 mi (2.4 km) west of the cape. Kialagvik Formation.
SYSTEMATIC DESCRIPTIONS 35

Toarcian for the lowest part of the Kialagvik Formation as exposed at Wide Bay. Nonetheless, it could 

represent float, as shown (1) by its association with 

three fragments of Erycitoides of late early Bajocian 

age, (2) by the occurrence of Erycitoides howelli 

(White) only 100 m farther south along the shore at 

USGS Mesozoic loc. 10807, and (3) by a field label 

written by S. R. Capps on Aug. 13, 1921, stating that 

the fossils collected at USGS Mesozoic loc. 10806 

"[m]ay be partly erratic. Part came from talus at base 

of a bluff." It is possible, also, that the specimen of 

Hammatocems was originally collected from upper 

Toarcian beds at Puale Bay, or that it was derived 

after early Bajocian time by erosion of Lower Jurassic 

beds that underlie Wide Bay and that to date have 

furnished the ammonite Waehneroceras of Hettangian 

age (Imlay, 1981, p. 12, pi. 2, figs. 14, 15). It is also 

possible that the specimen of Hammatoceras was collected along the south side of a fault that is uplifted on 

its south side.

Figured specimen. USNM 335958.

Occurrence. Kialagvik Formation, at USGS 

Mesozoic loc. 10806 at west base of a spit about 3 mi 

(4.8 km) from the southwest end of Wide Bay, Alaska 

Peninsula. Probably in SE%SW% sec. 10, T. 33 S., R. 

45 W., of the Ugashik (B-2) quad.

Genus Erycitoides Westermann, 1964 

Erycitoides howelli (White)

Plate 1, figure 7

One small, laterally crushed specimen closely resembles the coarsely ribbed inner whorls of certain 

lectotypes of E. howelli (White) (1889, p. 68, pi. 12, figs. 

1, 2; pi. 14, figs. 2, 3) as figured by Westermann (1964, 

pi. 44, pi. 45, figs. 2a,b; pi. 47). The specimen has a 

fairly wide umbilicus. It bears strong, fairly widely 

spaced primary ribs that pass near the middle of the 

flanks into pairs of slightly weaker secondary ribs that 

weaken ventrally. A few fairly strong ribs arise high 

on the flanks between the rib pairs. All secondary ribs 

weaken near the midline of the venter, which bears a 

fairly sharp, low keel. All ribs incline gently forward 

on the flank and incline more strongly forward on the 

venter.

The species is possibly also represented at USGS 

Mesozoic loc. 22718 by one poorly preserved fragment 

of an outer whorl that bears ribbing similar to that on 

the adult lectotype (Westermann, 1964, pi. 44).

Occurrence. Red Glacier Formation, float at USGS 

Mesozoic loc. 21234 and probably also at the same 

place as USGS Mesozoic loc. 21233 about 380-480 ft 

(126-146 m) above Lower Jurassic volcanic rocks 

exposed southwest of Tuxedni Bay on the west side of 

Cook Inlet.

Subgenus Kialagvikes Westermann, 1964 

Erycitoides (Kialagvikes) cf. E. kialagvikensis (White)

Plate 1, figure 8

One laterally crushed specimen preserved on a slab 

of black shale represents parts of two whorls. The 

outermost whorl bears ribbing similar to that near the 

adapical end of the body chamber on finely ribbed 

specimens of Erycitoides (Kialagvikes) kialagvikensis 

(White) as figured by Westermann (1964, pi. 62, figs. 

2a,b, and 3; pi. 63, figs. la,b). Its primary ribs incline 

forward on the lower parts of the flanks and are of 

variable strength. Its strongest ribs terminate in 

weak, radially elongate tubercles near the middle of 

the flanks. Its secondary ribs are uniform in strength, 

curve backward on the upper part of the flanks, and 

then curve slightly forward on the margins of the 

venter. On the inner whorl the primary ribs appear to 

be weak and nearly uniform in strength.

Figured specimen. USNM 335960.

Occurrence. Red Glacier Formation, 2,200-2,300 ft 

above base, at USGS Mesozoic loc. 21244F in Iniskin 

Bay Assoc. well 1 at a depth of 6,339-6,359 ft in SE% 

sec. 8, T. 5 S., R. 23 W., near Fitz Creek in the Iniskin 

Peninsula.

Family Sonniniidae Buckman, 1892 

Genus Sonninia Bayle, 1879 

Sonninia tuxedniensis Imlay

Plate 2, figure 1

Sonninia tuxedniensis Imlay, n. sp., 1964, U.S. Geol. Survey Prof. 

Paper 418-B, p. B32, pi. 2, figs. 5-10.

This species is represented to date in the Kialagvik 

Formation by one small septate specimen that in 

shape and ornamentation is identical with the inner 

whorls of the holotype (Imlay, 1964, pi. 2, fig. 10). The 

specimen, at a diameter of 54 mm, has a whorl height 

of 20 mm, a whorl thickness of 16 mm, and an umbilical width of 20 mm. The whorls bear prominent ribs 

that trend radially, or slightly adorally on flanks, 

become less prominent adorally, and nearly fade out 

adorally on the upper third of the outermost preserved 

whorl.

Sonninia tuxedniensis in the Wide Bay area has not 

to date been found with other genera and therefore 

cannot be dated precisely. By contrast, in the Cook Inlet 

area of southern Alaska it occurs with Normannites, 

Teloceras, Chondroceras, and Zemistephanus (USGS 

Mesozoic Iocs. 2999,3000, and 21266), which association 

is good evidence for correlation with the zone of Stephanoceras humphriesianum of Europe.

Hypotype. USNM 335970.

Occurrence. Kialagvik Formation at USGS Mesozoic loc. 10809 in the north-central part of sec. 17, T. 33
36 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

N., R. 45 W., at the southwest side of Wide Bay in the 

Alaska Peninsula.

Genus Fontannesia Buckman, 1902 

Fontannesia cf. F. carinata Buckman

Plate 2, figure 9

cf. Fontannesia carinata Buckman, 1905. Palaeontographical Soc. 

of London, p. CLXXXIX (p. 189): 1892, pi. 47, figs. 13, 14.

Fontannesia cf. F. carinata Buckman. Imlay, 1973, U.S. Geol. Survey Prof. Paper 956, p. 58, pi. 5, figs. 4-13.

One small ammonite from Puale Bay is characterized 

by fairly evolute coiling, a keeled venter, and fairly 

broad, flexuous ribs that are faint on the lowest part of 

the flanks but become much stronger and broader 

ventrally and fade out rather abruptly before reaching the keel. This ammonite shows considerable resemblance to small specimens of Fontannesia from eastern Oregon that were figured by Imlay (1973, p. 5, figs. 

4 and 10). Its ribs do not curve backward nearly as 

much as in specimens of Pelekodites figured by Westermann (1969, p. 126, pi. 32, figs. 1 and 2).

Figured specimen. USNM 335997.

Occurrences. Kialagvik Formation, atUSGS Mesozoic loc. 21235 on the northeast side of Puale Bay (see 

figs. 6 and 10) about 200 ft (61 m) below massive conglomeratic sandstone.

Family Oppeliidae Bonavelli, 1894

Genus Bradfordia Buckman, 1910

Bradfordia costidensa Imlay

Plate 1, figures 9-12

Bradfordia costidensa Imlay, n. sp. 1964, U.S. Geol. Survey Prof. 

Paper 418-B, p. B39, pi. 8, figs. 1-10.

This species is fairly common in the Wide Bay area 

in association with the ammonites Otoites, Stephanoceras, Parabigotites, Eudmetoceras(Euaptetoceras), and 

Sonninia, (Papilliceras). It is represented in the Puale 

Bay area by one small, immature specimen that is 

associated with Fontannesia.

This species is characterized by an elliptical whorl 

section, gently convex flanks, a narrowly rounded venter, a fairly narrow umbilicus, a vertical umbilical 

wall, a sharp umbilical edge, and fine to fairly fine 

falcoid ribs that are strongest on the upper part of the 

flanks and become much weaker adorally on the body 

chamber. Small, immature forms of Bradfordia costidensa Imlay show more resemblance to Lissoceras 

bakeri Imlay (1962, pi. 1, figs. 1-6, 9-12), but differ by 

having much stronger ribbing at a comparable size 

and by its umbilical wall rounding more abruptly into 

its flanks.

Types. Hypotype USNM 335961 and 335962.

Occurrences. Kialagvik Formation in the Wide 

Bay area at USGS Mesozoic Iocs. 19742,19786,19798, 

19823, 19850, 19852, 19884, 21256, 21257, and many 

other localities (see table 4). It occurs in the Kialagvik 

Formation in the Puale Bay area at USGS Mesozoic 

loc. 21235.

Family Otoitidae Mascke, 1907 

Docidoceras (Pseudocidoceras) widebayense Westermann

Plate 1, figs. 20, 24

Docidoceras (Pseudocidoceras) ividebayense Westermann, 1969, 

Bulls. American Paleontology, v. 57, no. 255, p. 137-146, pis. 

34-37.

This species is characterized (1) by a depressed whorl 

section, (2) by its adult body chamber becoming more 

evolute adorally, (3) by its ribs changing adorally from 

fairly weak and closely spaced on the septate whorls to 

very strong and widely spaced on the body chamber, 

(4) by its primary ribs on the outermost whorl inclining 

forward on the lower third of the flanks where they 

terminate in small tubercles, (5) by the tubercles passing into pairs of slightly weaker secondary ribs, and 

(6) by the secondary ribs curving strongly adorally on 

the venter of the body whorl.

This species has been found at many places on the 

southeast side of Wide Bay and at one place on the 

northwest side. Associated taxa include Sonninia 

(Alaskina) alaskensis Westermann, S. (Euhoploceras) 

bifurcata Westermann, Praeoppelia oppeliiformis 

(Westermann), Pseudoliocerasmaclintochifastigatum 

Westermann, and Eudmetoceras (Euaptetoceras) klimakomphalum discoidale Westermann. These in association show that the beds containing D. (P.) widebayense Westermann correlate with the European 

zone of Sonninia sowerbiji.

Hijpotype. USNM 335965.

Occurrences. Kialagvik Formation at USGS Mesozoic Iocs. 12405, 19801, 19862, 19869, 21251, 21252, 

31958, 32293, and 32296.

Otoites cf. O. contractus (J. de C. Sowerby)

Plate 1, figures 13-17

This genus is represented on the Alaska Peninsula 

by four fragments, of which two fit together as part of 

the body whorl and are somewhat crushed laterally. 

The other two specimens are much smaller, and bear 

very fine, closely spaced secondary ribs that outnumber the slightly stronger primary ribs about 4 to 

1. Those secondary ribs greatly resemble the secondary ribs on the inner whorls of the holotype of Otoites 

contractus (J. de C. Sowerby) from England (Buckman, 1920, pi. 158) and of specimens from eastern 

Oregon (Imlay, 1973, pi. 39, figs. 1 and 7) and from 

Germany (Westermann, 1954, p. 92, pi. 1, figs. 4, 5).
SYSTEMATIC DESCRIPTIONS 37

The ribs on the body whorl become much coarser and 

sparser adorally. They arise by threes from the primary ribs at the adapical end of the body chamber and 

by twos at the adoral end of that chamber. The secondary ribs arise from weak tubercles on the small septate whorls and from prominent tubercles on the body 

chamber. The coarseness of ribbing on the body whorl 

is likewise comparable to that on the specimens illustrated by Buckman and Westermann as just listed.

Figured specimens. USNM 335963 and 335964.

Occurrence. Upper part of the Kialagvik Formation at USGS Mesozoic loc. 21257 in the Wide Bay area 

on the Alaska Peninsula.

Family Sphaeroceratidae Buckman, 1920

Genus Chondroceras Mascke, 1907 

Chondroceras cf. C. colnetti (McLearn)

Plate 2, figures 10, 13

Two laterally crushed adult specimens resemble 

Chrondroceras colnetti (McLearn) (1929, p. 15, pi. 13, 

figs. 4, 5) by having high, sharp ribs that do not 

weaken adorally. Most of their primary ribs bifurcate, 

or trifurcate a little below the middle of the flanks. 

Most forked ribs are separated by a single rib that 

arises freely near the middle of the flanks. The ribbing 

differs from that on C. marchandi McLearn (1929, p. 

14, p. 12, figs. 4,5) by being much sharper and higher.

Figured specimens. USNM 335998 and 335999.

Occurrence. Nizina Mountain Formation. Float at 

USGS Mesozoic loc. 28682 in the Wrangell Mountains.

Family Stephanoceratidae Neumayr, 1875 

Genus Normannites Munier-Chalmas, 1892

Subgenus Itinsaites McLearn, 1927 

Normannites (Itinsaites?) variabilis Imlay

Plate 2, figures 6-8

Normannites (Itinsaites?) variabilis Imlay, 1964, U.S. Geol. Survey 

Prof. Paper418-B, p. B44, pi. 13, figs. 9,12-16; pi. 14, figs. 12,14.

Six specimens from the Wrangell Mountains are 

assigned to this species mainly because their ribbing 

changes from fine and dense on their septate whorls to 

fairly coarse and sparse on their body chamber. This is 

shown well on one lappeted adult (pi. 2, fig. 6), which 

greatly resembles certain paratypes (Imlay, 1964, pi. 

13, fig. 13 and pi. 14, fig. 12). Because of lateral crushing the tubercles appear to be lower on the flanks of the 

specimens from the Wrangell Mountains than on the 

type specimens from north of Cook Inlet.

Hypotypes. USNM 335973-335975.

Occurrence. Nizina Mountain Formation at USGS 

Mesozoic loc. 28682 in the Wrangell Mountains.

Genus Stephanoceras Wadgen, 1869 

Subgenus Skirroceras Mascke, 1907

Stephanoceras (Skirroceras) cf. S. (S.) leptogyrale (Buckman) 

Plate 2, figures 2-5

Stephanoceras (Skirroceras) cf. S. (S.) leptogyrale (Buckman). Imlay, 

1973, p. 88, pi. 46, fig. 15.

This species is represented by two internal molds 

which show the characteristics of the inner whorls 

very well. Those whorls bear ribs nearly as fine as 

those in S. (S.) leptogyrale (Buckman) (1924, pi. 576) 

from England. The outermost preserved whorl bears 

somewhat coarser and more widely spaced ribs than 

on S. (S.) leptogyrale.

Figured specimen. USNM 335971 and 335972.

Occurrences. Kialagvik Formation at USGS Mesozoic loc. 19823 and 21257, which are respectively in the 

NW cor. sec. 30, T. 33 S., R. 44 W., and in the NE^SW1^ 

sec. 28, T. 32 S., R. 44 W., near Wide Bay on the Alaska 

Peninsula.

Genus Teloceras Mascke, 1907 

Teloceras cf. T. blagdeni (Sowerby)

Plate 2, figures 12, 14

This species is represented by two crushed and distorted molds of which both exhibit fairly evolute coiling, coarse, widely spaced primary ribs, somewhat 

weaker secondary ribs, and prominent lateral tubercles. One of the specimens is an internal mold, which 

shows parts of three whorls of which the inner two are 

septate. The other specimen is an external mold, 

which shows parts of two whorls that closely resemble 

the outer two whorls shown on the internal mold. Presumably, the outermost whorl on each specimen represents part of the body chamber. On the outermost 

septate whorl of the internal mold the secondary ribs 

arise in bundles of three from four successive lateral 

tubercles. In addition, one secondary rib arises freely 

between the branched ribs along the zone of furcation. 

All these ribs appear to incline slightly forward.

Adorally on the outermost whorl of the external 

mold the ribs and tubercles become considerably 

stronger and more widely spaced, but the secondary 

ribs remain relatively much weaker than the primary 

ribs. The secondary ribs outnumber the primary ribs 

about three to one and arise mostly from the tubercles, 

but a few arise freely between the tubercles. All 

secondary ribs incline forward on the upper parts of 

the flanks. Similar secondary ribs are apparent on the 

fragmentary outermost whorl of the internal mold.

These specimens of Teloceras have appreciably 

stronger ribs and tubercles than occur on T. itinsae 

McLearn at comparable sizes (Imlay, 1964, pi. 23, figs. 

9, 10, pi. 24, figs. 1-5, 7). In this respect, they show
38 EARLY AND MIDDLE BAJOCIAN AMMONITES FROM SOUTHERN ALASKA

more resemblance to T. blagdeni (Sowerby) (Weisert, 

1932, p. 168, pi. 18, fig. 2; Arkell, 1933, pi. 34, fig. 5), 

which in Europe characterizes the upper part of the 

zoneofStephauocerashumphriesiamun (Weisert, 1932, 

p. 185), but has been recorded as high as the middle of 

the upper Bajocian (Arkell, 1956, p. 99, 278, 483).

Figured specimens. USNM 336001 and 336000.

Occurrence. Nizina Mountain Formation at USGS 

Mesozoic loc. 28682 in the Wrangell Mountains.

REFERENCES CITED

Arkell, W. J., 1933. The Jurassic system in Great Britain: Oxford, 

Clarendon Press, 681 p., 41 pis.

 1956, Jurassic geology of the world: London, Oliver & Boyd,

806 p., 46 pis., 102 figs. 

Arkell, W. J., Kummel, Bernhard, and Wright, C. W., 1957, Mesozoic

Ammonoidea, in Moore, R. C., ed., Treatise on invertebrate

paleontology, part L, Mollusca 4, Cephalopoda, Ammonoidea:

New York and Lawrence, Kans., Geol. Soc. America and Univ.

Kansas Press, p. L80-L437. 

Buckman. S. S., 1909-1930. Type ammonites: London, privately

published, v. 1-7 (see v. 3, pi. 158, 1920). 

Capps, S. R., 1922, The Cold Bay district, Alaska: U.S. Geol. Survey

Bull. 739-C, p. 77-116, pi. 2, figs. 5, 6. 

Detterman, R. L., 1963, Revised stratigraphic nomenclature and

age of the Tuxedni Group in the Cook Inlet region, Alaska: U.S.

Geol. Survey Prof. Paper 475-C, p. C30-C34. 

Detterman. R. L., and Hartsock, J. K., 1966, Geology of the IniskinTuxedni region, Alaska: U.S. Geol. Survey Prof. Paper 512, 78

p., 6 pis., 7 figs. 

Grantz, Arthur, 1965, Geologic maps and cross sections of the Nelchina area, south-central Alaska: U.S. Geol. Survey open-file

rept, 4 sheets, scale 1:63,360. 

Imlay, R. W., 1952, Correlation of the Jurassic formations of North

America, exclusive of Canada; Geol. Soc. America Bull., v. 63,

no. 9, p. 953-992, 2 correlation charts.

 1962, Late Bajocian ammonites from the Cook Inlet region, 

Alaska: U.S. Geol. Survey Prof. Paper 418-A. p. A1-A15, pis. 

1-5, 4 figs.

 1964, Middle Jurassic (Bajocian) ammonites from the Cook 

Inlet region, Alaska: U.S. Geol. Survey Prof. Paper 418-B, p. 

1-61, pis. 1-29, 5 figs.

 1973, Middle Jurassic (Bajocian) ammonites from eastern 

Oregon: U.S. Geol. Survey Prof. Paper 756,100 p., 48 pis., 8 figs.

 1980, Middle Jurassic (Bathonian) ammonites from southern 

Alaska: U.S. Geol. Survey Prof. Paper 1091, p. 1-42, 12 pis., 11 

figs.

 1981. Early Jurassic ammonites from Alaska: U.S. Geol. Survey Prof. Paper 1148. 49 p., 12 pis.. 14 figs.

 1982, Late Bajocian ammonites from southern Alaska: U.S.

Geol. Survey Prof. Paper 1189, 19 p.. 7 pis., 7 figs. 

Imlay, R. W., and Detterman, R. L., 1973, Jurassic paleobiogeography of Alaska: U.S. Geol. Survey Prof. Paper 801, 34 p., 15

figs.

 1977, Some Lower and Middle Jurassic beds in Puale BayAlinchak Bay area, Alaska Peninsula: Am. Assoc. Petroleum 

Geologists Bull, v. 61, p. 607-611, 2 figs.

Karlstrom, T. N. V., 1964, Quaternary geology of the Kenai Lowland 

and glacial history of Cook Inlet region, Alaska: U.S. Geol. 

Survey Prof. Paper 443, 69 p.. 7 pis., 14 figs.

Kellum. L. B., Davies, J. N., and Swinney, C. M., 1945, Geology and 

oil possibilities of the southwestern part of the Wide Bay anticline. Alaska: U.S. Geol. Survey Prelim. Rept, 17 p., illus., incl. 

geol. map.

Martin, D. C., 1926, The Mesozoic stratigraphy of Alaska: U.S. Geol. 

Survey Bull. 776, 493 p.

MacKevett, E. M., Jr., 1969, Three newly named Jurassic formations 

in the McCarthy C-5 quadrangle, Alaska: U.S. Geol. Survey 

Bull. 1274-A, p. A35-A49, figs. 3-8.

 1971, Stratigraphy and general geology of the McCarthy C-5 

quadrangle, Alaska: U.S. Geol. Survey Bull. 1323, 35 p.

McLearn, F. H., 1929, Contributions to the stratigraphy and paleontology of Skidgate Inlet, Queen Charlotte Islands, British 

Columbia: Canada Nat. Mus. Bull. 54. Geol. Ser., no. 49, p. 1-27, 

16 pis.

Smith, W. R., 1926, Geology and oil developments of the Cold Bay 

district: U.S. Geol. Survey Bull. 783, p. 63-88.

Smith, W. R., and Baker, A. A., 1924, The Cold Bay-Chignik district, 

Alaska: U.S. Geol. Survey Bull. 755, p. 151-218.

Weisert, Kurt, 1932, Stephanocems im Schwabischen Braunen Jura 

Delta: Palaeontographica, v. 76, p. 121-191, pis. 15-19.

Westermann, G. E. G., 1954, Monographie der Otoitidae (Ammonoidea): Geol. Jahrb. Beihefte, no. 15, 364 p., 33 pis.

 1964, The ammonite fauna of the Kialagvik Formation at 

Wide Bay, Alaska Peninsula, part 1, Lower Bajocian (Aalenian): Bulls. Am. Paleontology, v. 47, p. 329-503, pis. 44-76,37 figs.

 1969, The ammonite fauna of the Kialagvik Formation at 

Wide Bay, Alaska Peninsula, Part 2, Sonninia soirerbyi zone 

(Bajocian): Bulls. Am. Paleontology, v. 57, no. 255, 226 p., pis. 

1-47, 56 figs.

White, C. A., 1889, On invertebrate fossils from the Pacific coast: 

U.S. Geol. Survey Bull. 51, 102 p., 14 pis.
PLATES 1 AND 2

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 1-4. Asthenoceras cf. A. delicatum Imlay (p. 25).

1,2. Ventral and lateral views of specimen, USNM 335956 from USGS Mesozoic loc. 19862. 

3, 4. Ventral and lateral views of specimen, USNM 335957 from USGS Mesozoic loc. 19862. 

5, 6. Hammatoceras sp. (p. 27). Ventral and lateral views of specimen, USNM 335958 from USGS Mesozoic loc. 10806.

7. Erycitoides howelli (White) (p. 35). Lateral view of hypotype USNM 335959 from USGS Mesozoic loc. 21234.

8. Erycitoides (Kialagvikes) cf E. (K.) kialagvikensis (White) (p. 35). Lateral view, USNM 335960 from USGS Mesozoic loc. 21244F. 

9-12. Bradfordia costidensa Imlay (p. 36).

9, 10. Lateral and ventral views of hypotype, USNM 335961 from USGS Mesozoic loc. 19742. 

11, 12. Lateral and ventral views (x 2) of hypotype, USNM 335962 from USGS Mesozoic loc. 21235. 

13-17. Otoites cf. O. contractus (J. de C. Sowerby) (p. 36).

13-15. Lateral and ventral views of adoral end of the body whorl. The fragment shown in figure 15 fits only the adapical

end of the specimen shown in fig. 13, USNM 335963 from USGS Mesozoic loc. 21257. 

16, 17. Lateral and ventral views (x 2) of inner whorl, USNM 335964 from USGS Mesozoic loc. 21257. 

18, 19. Tmetoceras scissum (Benecke) (p. 27).

18. Lateral view of hypotype, USNM 335965 from USGS Mesozoic loc. 21233.

19. Lateral view of hypotype, USNM 335966 from USGS Mesozoic loc. 21234. 

20, 24. Docidoceras (Pseudocidoceras) widebayense Westermann (p. 36).

Lateral and ventral views of hypotype, USNM 335967 from USGS Mesozoic loc. 19862. 

21-23. Tmetoceras kirki flexicostatum Westermann (p. 27),

21. Lateral view of hypotype, USNM 335968 from USGS Mesozoic loc. 21254. 

22, 23. Ventral and lateral view of part of an outer whorl of hypotype USNM 335969 from USGS Mesozoic loc. 21254.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1322 PLATE 1

V.

vcy

20 **da*^ 21 V 22 

ASTHENOCERAS, TMETOCERAS, HAMMATOCERAS, ERYCITOIDES, E. (KIALAGVIKES), BRADFORDIA, AND OTO/TES
PLATE 2

[Figures natural size unless otherwise indicated]

FIGURE 1. Sonninia tuxedniensis Imlay (p. 35).

Hypotype, USNM 335970 from USGS Mesozoic loc. 10809. (p. 35). 

2-5. Stephanoceras (Skirroceras) cf. S. (is.) leptogyrale Buckman(p. 37).

2-4. Lateral and ventral views of specimen, USNM 335971 from USGS Mesozoic loc. 19823.

5. Lateral view of inner whorls of specimen, USNM 335972 from USGS Mesozoic loc. 21257. 

6-8. Normannites (Itinsaites?) variabilis Imlay (p. 37).

6. Hypotype of adult body chamber, USNM 335973 from USGS Mesozoic loc. 28682.

7. Hypotypes of adapical end of body whorl, USNM 335974 from USGS Mesozoic loc. 28682.

8. Hypotype of part of an outer whorl, USNM 335975 from USGS Mesozoic loc. 28682. 

9. Fontannesia cf. E. carinata Buckman (p. 36).

Lateral view (x 2) of specimen, USNM 335997 from USGS Mesozoic loc. 21235. 

10, 13. Chondroceras cf. C. colnetti (McLearn) (p. 37).

10. Lateral view of rubber cast of external mold of body whorl, USNM 335998 from USGS Mesozoic loc. 28682. 

13. Lateral view of body whorl, USNM 335999 from USGS Mesozoic loc. 28682. 

11. Pseudolioceras cf. P. whiteavesi (White) (p. 25).

Laterally crushed specimen, USNM 336000 from USGS Mesozoic loc. 29341. 

12, 14. Teloceras cf. T. blagdeni (Sowerby) (p. 37).

12. Internal mold of specimen, USNM 336001 from USGS Mesozoic loc. 28682.

14. Rubber cast of external mold of specimen USNM 356002 from USGS Mesozoic loc. 28682.
GEOLOGICAL SURVEY

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PROFESSIONAL PAPER 1322 PLATE 2

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PSEUDOL/OCERAS, SONNIMA, FONTANNESIA, CHONDROCERAS, NORMANMTES, STEPHANOCERAS (SK/RROCERAS),

AND TELOCERAS

 U.S. GOVERNMENT PRINTING OFFICE: 1985-461-^36:424