A Late Oligocene or 

Earliest -Miocene Molluscan 

Fauna from 

Sitkinak Island, Alaska 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1233 
A Late Oligocene or Earliest 

Miocene Molluscan 

Fauna From 

Sitkinak Island, Alaska 

By RICHARD C. ALLISON and LOUIE MARINCOVICH, JR. 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1233 

Describes the late 0 ligocene or earliest Miocene 

molluscan fauna from the Narrow Cape Formation 

on Sitkinak Island, noting the ntixture of Asiatic, 

North American, and enden1ic high-latitude North 

Pacific taxa. 

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

JAMES G. WATT, Secretary 

GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Library of Congress Cataloging in Publication Data 

Allison, Richard C., 1935-

A late Oligocene or earliest Miocene molluscan fauna 

from Sitkinak Island, Alaska. 

(Geological Survey Professional Paper; 1233) 

Bibliography: p. 9-10. 

Supt. of Doc. no.: I 19.16:1233 

1. Mollusks, Fossil--Alaska--Sitkinak Island. 

2. Paleontology--Oligocene. 3. Paleontology--Miocene. 

I. Marincovich, Louie. II. Title. III. Series. 

QE801.A44 564' .09798'4 81-607925 

AACR2 

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

Washington, D.C. 20402 
PLATE 

CONTENTS 

Abstract ....................................................................................................................................................... . 

Introduction 

Faunal composition ................................................................................................................................. . 

Age and correlation ................................................................................................................................. . 

Relation to the type Narrow Cape Formation of Kodiak Island ............................................... . 

Paleoecology ............................................................................................................................................... . 

Water depth ......................................................................................................................................... . 

Water temperature ........................................................................................................................... . 

Paleozoogeographic affinities ............................................................................................................... . 

References cited ......................................................................................................................................... . 

Index ............................................................................................................................................................. . 

ILLUSTRATIONS 

[Plates follow index) 

1. Acila, Clinocardium, Crenella, Cyclocardia, Hiatella, Liocyma, Macoma, Mya. 

Page 

1 

2 

2 

4 

5 

6 

6 

6 

8 

8 

11 

2. Periploma, Pitar, ?Serripes, Ancistrolepis, $pisula, Bruclarkia, ?Beringius, Buccinum, Parasyrinx, Priscofusus. 

3. Echinophoria, Calyptraea, Turritella, Epitonium, Musashia, Natica, Polinices. 

Page 

FIGURE 1. Index map of the Kodiak Island area, Alaska, showing outcrops of the Narrow Cape Formation 

on Sitkinak Island .................................................................................................................................................................................... 2 

2. Stratigraphic section of the Narrow Cape Formation on Sitkinak Island, Alaska, showing 

megafossillocalities --------·--·················································································································································-··················· 3 

3. Chart showing inferred paleobathymetry for each fossil locality, based on the fossil mollusks .............................................. 7 

TABLES 

Page 

TABLE 1. Occurrence in Pacific Northwest Tertiary molluscan stages of selected species from the Narrow Cape 

Formation on Sitkinak Island .............................................................................................................................................................. 4 

2. Benthic foraminifers from the Narrow Cape Formation on Sitkinak Island ......................................................................... :...... 4 

3. Reported occurrences in North Pacific strata of some mollusks from the Narrow Cape Formation 

on Sitkinak Island ·················-···········································-······················-················································-·····································~-----··- 5 

4. Maximum known depth ranges of some living taxa found in the Narrow Cape Formation on 

Sitkinak Island .......................................................................................................................................................................................... 6 

5. Latitudinal ranges and marine climatic tolerances of living analogs of some mollusks from the 

Narrow Cape Formation on Sitkinak Island .................................................................................................................................... 8 

6. Occurrences of fossil mollusks in the Narrow Cape Formation, Sitkinak Island, Alaska .......................................................... 9 

III 

A LATE OLIGOCENE OR EARLIEST MIOCENE 

MOLLUSCAN FAUNA FROM SITKINAK ISLAND, ALASKA 

By RICHARD C. ALLISON and LOUIE MARINCOVICH, JR. 

ABSTRACT 

TheN arrow Cape Formation of Sitkinak Island, in the western 

Gulf of Alaska, contains a marine molluscan fauna of late 

Oligocene or earliest Miocene age that represents the Juanian 

Stage [= Echinophoria apta Zone] of the Pacific Northwest 

(Washington and Oregon) provincial molluscan chronology. The 

Narrow Cape Formation on Sitkinak Island is older than the type 

Narrow Cape Formation on Kodiak Island, which contains 

mollusks referable to the Newportian Stage. The fauna of the 

Narrow Cape Formation of Sitkinak Island lived in the outer 

neritic zone in a cool-temperate marine climate. The co-occurrence 

of taxa with Asiatic, North American, and high-latitude North 

Pacific zoogeographic affinities makes this fauna especially 

important for the development of circum-North Pacific chronostratigraphic correlations. 

INTRODUCTION 

Upper Oligocene or lowest Miocene strata, predominantly of marine siltstone and approximately 

210 m thick, crop out on Sitkinak Island, south of 

Kodiak Island, in the western Gulf of Alaska (fig. 1). 

Terrestrial sedimentary rocks containing coal and 

fossil plants have long been known from Sitkinak 

Island (Dall, 1896; Smith, 1939), but the marine beds 

were not discovered until 1962, during the course of 

field work by George W. Moore of the U.S. Geological 

Survey. MacNeil (1965, p. G9) made the first literature reference to these marine strata and referred 

them to the uEchinophoria a pta zone of the Oligocene 

and Miocene." Moore (1967) published a geologic map 

of the Kodiak Island area showing these marine beds 

as Miocene in age. In 1969 Moore named and 

described the Narrow Cape Formation with its type 

section at Narrow Cape on Kodiak Island, and 

assigned the marine siltstone of Sitkinak Island to 

the Narrow Cape Formation (fig. 2). The first published account of mollusks from the Narrow Cape 

Formation on Sitkinak Island was by Allison (1976, 

1978), who assigned these strata to the Juanian 

Stage [ =Echinophoria apta Zone], which he considered 

to be of late Oligocene and early Miocene age. This 

fauna has great significance for circum-North Pacific 

chronostratigraphic correlation because of its mixture 

of North American, Asiatic, and endemic highlatitude molluscan taxa. Our purpose here is to document this fauna and discuss its paleoecology, faunal 

affinities, and correlations. 

Fossils examined for this study were collected by 

George W. Moore in 1962, 1975, and 1978, by geologists 

of Marathon Oil Co. in 1971, and by geologists of 

Mobil Oil Co. in 1971 and 1975. These collections are 

housed at the U.S. Geological Survey in Menlo Park . , Cahf., and the University Museum, University of 

Alaska, Fairbanks, Alaska. The illustrated specimens 

are housed at the U.S. National Museum of Natural 

History, Washington, D.C., and the University of 

Alaska Museum, Fairbanks. 

We are indebted to Mobil Oil Co. for providing data 

for the columnar section (fig. 2). George W. Moore of 

the U.S. Geological Survey and John Armentrout of 

Mobil Oil Company have provided valuable information concerning the stratigraphy of the Narrow Cape 

Formation on Sitkinak Island. Kristin McDougall 

examined the benthic foraminifers from four of our 

samples; Warren 0. Addicott made helpful suggestions on the report. Photographs of the fossils were 

made by Kenji Sakamoto. All are of the U.S. Geological Survey. 

FAUNAL COMPOSITION 

The molluscan fauna of the Narrow Cape Formation on Sitkinak Island (pls. 1-3) consists of at least 

the 44 recognizable taxa listed in table 6. Specimens 

1 
2 MOLLUSCAN FAUNA FROM SITKINAK ISLAND, ALASKA 

0 500 ~ 1000 KILOMETERS 

rJV o~o .. it~k .. in.ak I. 

~I 9 ~ 50 100 KILOMETERS 

1-----------Tu-gidak I. ~~-'---_ ~-------1 

EXPLANATION 

Surficial deposits (Quaternary) 

Narrow Cape Formation(Oligocene or Miocene) 

Sitk~nak Formation (Oligocene) 

Sitkalidak Formation (Eocene and 

Oligocene) 

X--X Measured stratigraphic 

section (see fig. 2) 

M7334 Fossil locality 

Contact 

Fault-Dotted where 

concealed 

--+ · · · Anticline-Dotted where 

concealed 

--fT·· · Overturned anticlineDotted where concealed -+ · · · Syncline-Dotted where 

concealed 

0 10 KILOMETERS 

FIGURE I.-Index map of the Kodiak Island area, Alaska, showing outcrops ofthe Narrow Cape Formation on Sitkinak Island. 
FAUNAL COMPOSITION 3 

were examined from 17 collections within a measured 

stratigraphic section (fig. 2), augmented by 10 collections from unknown stratigraphic positions and two 

collections (M7334 and M7335) from a separate outcrop (fig. 1). Among the 44 recognizable taxa are 22 

bivalves, 20 gastropods, one cephalopod, and one 

Age 

Q) 

c: 

Q) 

u 

0 

~ 

>-

-.:::: 

cu 

Q) 

0 

Q) 

c: 

Q) 

u 

0 

.!2"> 

0 

~ cu 

.....1 

Unit Lithology 

c: 

0 

·;:: 

cu 

E 

0 

LL 

Q) 

c. 

cu -.-.-· u 

~ 

g 

cu 

z 

·- •o-•• 

-·-·-· 

·-·-· 

-;-=.__~ -:-..:....::::-: 

-:-__:_--:-_:_ ~ 

~) :.._-: _:.__-:-. 

·-·-·-· ~ ~ • o ·: ~: • • ~ o' d. ~~ ...... ,• .... 

Fossil locality 

number 

M6589 

M6588 

M6587 

M6586 

M6585 

M6499 

M6584 

M6583 

M6582 

M6581 

M6580 

M6579 

M6578 

M6577 

M6576 

M6575 

Mainly siltstone with some beds containing scattered 

pebbles and cobbles, and scattered to locally 

abundant calcareous concretions. Occasional thin 

beds of very fine sandstone. Megafossils throughout 

siltstone and commonly in concretions; locally 

abundant. Total thickness of formation about 210m 

METERS 

50 

25 

0 

"--'t- ;....:.,....;;-...:..,.....--.;:.. 0 -

0

.:;.

0 --..

0

1------------ Oisconformity 

FIGURE 2.-Stratigraphic section of the Narrow Cape Formation on Sitkinak Island, Alaska, showing megafossil localities. 

Adapted from data supplied by Mobil Oil Co., George W. Moore (oral commun., 1979), and Nilsen and Moore (1979). 

See figure 1 for geographic location of section. 
4 MOLLUSCAN FAUNA FROM SITKINAK ISLAND, ALASKA 

scaphopod. 

The fauna contains a mixture of western North 

American, endemic high-latitude North Pacific, and 

Asiatic taxa (Allison, 1978). This aspect of the fauna 

holds the promise of correlating upper Oligocene or 

lowermost Miocene strata along the margin of the 

North Pacific from Japan to California. 

AGE AND CORRELATION 

The mollusks of the Narrow Cape Formation on 

Sitkinak Island are referable to the Juanian Stage of 

the provincial molluscan chronology of the Pacific 

Northwest (Oregon and Washington) (Addicott, 

1976b; Allison, 1978). The Juanian Stage is coeval 

with the Echinophoria apta Zone of the Pacific Northwest (Armentrout, 1975; Addicott, 1976b; Allison, 

1978) and is mostly of late Oligocene age and partly 

of early Miocene age (Allison, 1976, 1978). 

The zonal fossil Echinophoria apta(Tegland) is 

present in one collection from Sitkinak Island (table 

6; pl. 3, fig. 1). Taxa suggesting that the Sitkinak 

Island marine strata are no older than the J uanian 

Stage or the E. apta Zone are: Macoma calcarea 

(Gmelin), M. incongrua (von Martens) of Kanno 

(1971), M. cf. M. moesta moesta (Deshayes), Pitar 

angustifrons (Conrad), Spisula cf. S. hannibali (Clark 

and Arnold), Natica clausa Broderip and Sowerby, 

Polinices ramonensis (Clark), and Priscofusus clarki 

Kanno (table 1). Species that suggest an age no 

younger than the Juanian Stage are Bruclarkia cf. B. 

andersoni (Wiedey), Neverita washingtonensis 

(Weaver), and Priscofusus clarki Kanno (table 1). 

The Echinophoria apta Zone corresponds to the 

upper part of the Zemorrian benthic foraminiferal 

Stage of California (Durham, 1944; Armentrout, 1975; 

Addicott, 1976b). This correlation is generally confirmed in the Narrow Cape Formation on Sitkinak 

Island by the presence of Zemorrian benthic foraminifers from four samples (table 2). No identifiable 

planktic microfossils were found. 

On the basis of its molluscan fauna, the Narrow 

Cape Formation on Sitkinak Island correlates with 

the J uanian part of the Poul Creek Formation in the 

northeastern Gulf of Alaska, with the Sooke Formation of Vancouver Island, British Columbia, Canada, 

and with the Pysht Formation of the Twin River 

Group (Snavely and others, 1978) of northwestern 

Washington. 

Asiatic taxa in the Narrow Cape Formation on 

Sitkinak Island permit general but unrefined correlations with late Oligocene to early Miocene formations of Japan, Sakhalin, and Kamchatka (table 3). 

Some of the Asiatic taxa useful in correlation are 

TABLE !.-Occurrence in Pacific Northwest Tertiary molluscan 

stages of selected species from the Narrow Cape Formation on 

Sitkinak Island 

Series Eo- Oligo-' Miocene cene cene 

Molluscan s:: s:: s:: s:: CIS CIS CIS 

stages CIS :il s:: s:: ·-e ..c: ·a u CIS liS 0 liS 

-~ ....: ·;;: ~ ·a i:l. ..c: Cii liS 

~ a: liS .!!! :I Q> 

(.!) ::s '":> z S!: 

Pelecypods: Acila (Acila) gettysburgensis (Reagan) ............ . Crenella porterensis Weaver ................................. J----+--+--+-----i---1 

Macoma (Macoma) calcarea (Gmelin) .............. . - ? -1----+----4----

Macoma (Macoma) incongrua (von 

Martens) of Kanno ............................................ . - ? -1-----1---+----+ 

Macoma (Macoma) cf. M. (M.) 

moesta moesta (Deshayes) .............................. . Macoma twinensis Clark ...................................... . --+--+-___,1- - - - ? - Pitar (Katherinella) angusti{rons 

(Conrad) ................................................................ . ?Se"ipes hamiltonensis (Clark) ........................ . Spisula cf. S. hannibali (Clark 

and Arnold) .......................................................... . 

- ?- -? 

Spisula albaria (Conrad),&.! ................................ . Gastropods: Bruclarkia cf. B. andersoni (Wiedey) ................ . Calyptraea cf. C. diegoana (Conrad) ................. M .. '----+-----4---1---+--+-----+ 

Echinophoria apta (Tegland) .............................. . Natica (Cryptonatica) clausa 

N!:t:!zriM~~ri~r::;hi;;~-;;;~i~---·············· 

-

(Weaver) ................................................................. .,..._--+---1 - ? - Polinices (Euspira) cf. P. (E.) 

lincolnensis (Weaver) ........................................ . Polinices (Euspira) ramonensis 

(Clark) ........................................................................ . Prisco{usus clarki Kanno .................................... . Prisco{usus aff. P. stewarti (Tegland) .............. . ?-- -? 

Clinocardium cf. C. makiyamae Kamada, Cyclocardia 

cf. C. subnipponica (Nagao), C. cf. C. tokunagai 

(Yokoyama), Mya grewingki Makiyama, and Turritella cf. T. chichibuensis Ida. These taxa suggest 

TABLE 2. -Benthic foraminifers from the Narrow Cape Formation on Sitkinak Islarid 

[Identifications by Kristin McDougall. M =megafossil locality, Mf= microfoBBillocality] 

C':) """ lt:l 0) 0) 0) ~ 0 0 § 0 

f3 f3 f3 

::s ::e ::e ::s '- '- '- '- 0) ClO co C'l ClO r:- ~ 0) 

""" lt:l lt:l 

i co co co 

Fossil localities ::e ::s ::e 

Foraminifers: 

Bathysiphon sanctaecrucis Cushman and Kleinpell........ x 

Bathysiphon sp ........................................................... . Bolivina marginata adelaidana· Cushman ..................... . and Kleinpell ........................................................... . 

----

)( 

Buccella mans{ieldi oregonensis (Cushman, 

Stewart, and Stewart) ............................................... . Cassidulina crassipunctata Cushman and 

Hobson .................................................•.................. Cibicides elmaensis Rau ................................ ? ••••••••••••••• .. ... 

gb;~~~!iJ'd-jja:C:iiic~·-secit·:::::::::::::::::::::::::::::::::::::::::::: .... Cyclammina spp .......................................................... x 

Dentalina consobrina d'Orbigny ................................... . Dentalina sp ................................................................ . .. . Elphidium sp................................................................ x 

Entosolenia sp. ofRau (1964) ....................................... . 

.... )( 

)( 

.... 

)( 

..... ?Entosolenia sp ............................................................ . .. . )( 

~71~:r:e::;::-~-:~~~~~:~:~!::::::::::::::::::::::::::::::::::::: -~-- ~:fj~fshd~M~~~p'jf;~tJ~:{~iciiiei································ and Moll) .................................................................. x 

.... 

)( .... 

)( 

)( 

Nonion planatum Cushman and Thomas ...................... . .. . ...... .... Pseudonodosaria conica (Neugeboren)............................ x )( )( 

?Trochammina sp ........................................................ x 

?Planktic foraminifers ................................................. . .... 

)( 

Miscellanea: 

?Radiolaria ................................................................. . . ... Ostracods ................................................................... . X 
AGE AND CORRELATION 5 

correlations with the I waki and Asagai Formations 

of the Joban Coal Field of Japan, the Ushikubitoge 

Formation and Nenokami Sandstone of the Chichibu 

Basin of Japal};-the Poronai Formation of Hokkaido, 

Japan, and the Nissakutan and Marie Formations of 

Sakhalin (table 3). Menner and others (1977, p. 83, 

table 1) and Gladenkov (1980, fig. 3) appear to refer 

these strata to the Gakhinian Stage of western 

Kamchatka and the Machigarian Stage of northern 

Sakhalin, which they placed in the upper Oligocene. 

TABLE 3.-Reported occurrences in North Pacific strata of some mollusks from the Narrow Cape Formation on Sitkinak Island 

Taxon 

Clinocardium cf. C. 

makiyamae 

Kamada, 1962. 

Cyclocardia cf. C. 

belogolouensis 

(Ilyina, 1963). 

Cyclocardia cf. C. 

subnipponica 

(Nagao, 1928). 

Cyclocardia cf. C. 

tokunagai 

(Yokoyama, 1924). 

Cyclocardia cf. C. 

wajampolkensis 

(Jlyina, 1963). 

Macoma cf. M. optiua 

(Yokoyama, 1923) 

Mya (?Arenomya) 

grewingki 

Makiyama, 1934. 

Reference Occurrence 

Kamada (1962) ........................ Asagai Formation of the Uchigo 

Group, Joban Coal Field, 

Japan. 

llyina (1963) ............................ Vayampol'sk Series, 

Kamada (1962) 

Kamada (1962); 

Ilyina (1963). 

llyina (1963); Menner and others ( 1977). 

Kamada (1962); 

Kanno, (1960); 

llyina (1963); Zhidkova and others, (1968; 

1972); Ikebe and others 1972); 

Kamchatka. 

........ ... Yamaga Formation of the Ashi- ya Group, northern Kyushu, 

Japan. 

Iwaki Forrnation of the Uchigo 

Group, Joban Coal Field, 

Japan. 

Asagai Formation of the Uchigo 

Group, Joban Coal Field, 

Japan. 

Vayampol'sk Series, Kamchatka. Viventekian Stage, "zone of Delectopecten pedroanus"; late Oligocene or early Miocene. 

Narrow Cape Forrnation, Kodiak Island, Alaska. Unga Conglomerate Member of the Bear Lake Formation, Alaska. Upper part of Bear Lake Forma- tion, Alaska (questionable 

occurrence). 

JobNu<::~:~~h~~~~k~~ra Formations, Taga Group. 

Nakayama Formation, Shirado Group. 

Honya Formation, Yunagaya 

Group. ' Chichibu Basin, Japan: Hikokubo Group: Nemokami Sandstone. Ushikubitoge Formation: Tomita Siltstone Member. 

Shirasu Sandstone Member. Fujina Formation, SW. Honshu, N15/N16 zones of Blow (1969). Kadonosawa Series, N. Honshu, 

Japan. 

"Sankebetsu Miocene," Hok- kaido, Japan. Kurile Islands, U.S.S.R.: Alekhin, Kamui, Shumnov Suites. Sakhalin, U.S.S.R.: Kurasii, Sertunai, Maruyam, 

Aleksandrov, Okobykai, 

Borskaya Suites. Kamchatka: Vayampol'sk Series. ll'insk, Kakert, Kuluven Suites. 

Kamada (1962); ........................ Akahira Formation, Chichibu 

MacNeil 0965). N!~~~~as:~dstone, Chichibu 

Basin, Japan. 

Asagai Formation, Joban Coal Field, Japan. Poronai Forrnation, Hokkaido, 

Japan. 

Marie Formation, Matchgar, 

Sakhalin, U.S.S.R. Maoka Group, S. Sakhalin, U.S.S.R. Nissakutan Fnrmation, 

Sakhalin, U.S.S.R. 

TABLE 3.-Continued 

Taxon 

Periploma (Aelga) 

besshoense 

(Yokoyama, 1924). 

Reference 

Kamada (1962); Kanno (1971); 

Ilyina (1963). 

Occurrence 

Yakataga and Poul Creek Formations, Alaska, Juan- ian(?) to Wishkahan(?). 

Asagai Formation of the Uchigo 

Group, Joban Coal Field, 

Japan. 

Shirasaka Formation of the Uchigo Group, Joban Coal Field, Japan. Poronai Formation, Hokkaido, 

Japan. 

Kuluven Suite, Kamchatka, U.S.S.R. 

Buccinum aff. B. kurodai 

Kanehara, 1937. 

Kamada (1962) ....................... Mizunoya and Honya FormaTurritella (Hataiella) cf. Kanno (1960); T. (H.) chichibuensis Kotaka (1959); 

Ida, 1952. Ikebe and others (1972). 

tions, Yunagaya Group, Joban Coal Field, Japan. 

Nutoya beds, Sakhalin, U.S.S.R. 

Chichibu Basin, Japan: 

Tachigase Formation[= Tat- sugase]: same as Akahira Formation (Blow, 1969, zones N5/N6). Nenokami Sandstone, Hikokubo Group. 

Dentalium Kanno (1971) . . .................... Poronai to Takinoue Formations, 

(Coccodentalium) Hokkaido, Japan. cf. D. (C.) nunomae Takeda, 1953, of Kanno (1971) . 

In western North America, as in Asia, the stratigraphic interval represented by the Narrow Cape 

Formation on Sitkinak Island has been variously 

assigned to the late Oligocene or early Miocene. In 

recent years,· Addicott's (1976a) study of mollusks 

from the upper part of the Twin River Group of 

western Washington has shown that the OligoceneMiocene boundary occurs high in the Echinophoria 

a pta Zone. He later proposed the J uanian Stage to 

coincide with the E. apta Zone (Addicott, 1976b). 

Using inferences drawn from planktic microfossil 

correlations, Allison (1976, 1978) independently concluded that the Juanian Stage was mostly of late 

Oligocene age, and that its uppermost part was of 

early Miocene age. The faunal composition of the 

Sitkinak Island beds (table 1) suggests that the 

Narrow Cape Formation there is coeval with the 

Pysht Formation of the Twin River Group of Snavely 

and others (1978) and is of late Oligocene or earliest 

Miocene age. 

RELATION TO THE TYPE NARROW CAPE 

FORMATION OF KODIAK ISLAND 

When Moore (1969) referred the Tertiary marine 

strata of Sitkinak Island to the Narrow Cape Formation, he realized that these beds were older than the 

type Narrow Cape Formation of Kodiak Island (fig. 

1). MacNeil (in Moore, 1969) regarded mollusks from 

the middle part of the type Narrow Cape Formation 

to be of middle Miocene age and mollusks near the 

base of the formation on Sitkinak Island to be of 

early Miocene age. Our opinion that the Narrow 

Cape Formation on Sitkinak Island is older than the 

type Narrow Cape Formation of Kodiak Island is the 
6 MOLLUSCAN FAUNA FROM SITKINAK ISLAND, ALASKA 

same as MacNeil's (in Moore, 1969), but we refer the 

latter to the Newportian molluscan Stage of late 

early and early middle Miocene age and to the late 

Saucesian through Luisian benthic foraminiferal 

Stages. Thus, the molluscan faunas of these two 

units suggest that the type Narrow Cape Formation 

is entirely younger than theN arrow Cape Formation 

on Sitkinak Island. The PiUarian molluscan Stage 

and the early Saucesian benthic foraminiferal Stage 

constitute a missing interval between the Kodiak 

Island and the Sitkinak Island marine strata. 

.·P~~EOECOLOGY 

WATER DEPTH 

The Narrow Cape For_mation on Sitkinak Island 

evidently was deposited in the outer neritic zone of 

the continental shelf (Allison, 1978). Most of the 

mollusk species are extinct or belong to genera with 

broad depth distributions, but a few taxa suggest 

probable lower depth limits and still fewer indicate 

probable upper depth limits. No shallowing or deepening trends are evident within the section. Table 4 

shows the maximum depth range known to us for 

some living taxa that also occur in the Sitkinak 

Island marine strata. Taxa not listed in table 4 either 

have very broad depth ranges; are extinct, or have no 

data available for them. 

TABLE 4.-Maximum known depth ranges of some living taxa 

found in the Narrow Cape Formation on Sitkinak Island 

Taxa 

Clinocardium ............................. . Macoma (Macoma) calcarea .................... . Macoma (Macoma) incongrua ......... . 

Macoma (Macoma) moesta moesta Mya .......... . ........................ . Pitar . .............................. . Serripes .................................................................. . Spisula .................................................................... . Ancistrolepis ................. . ................................. . Calyptraea ............................................................. . Musashia, s.l.................... . ....................... . 

Priscofusus (living analog: Fusinus) .... . Turritella ............................. . 

Minim urn depth 

(m) 

0 

0 

0 

0 

0 

0 

0 

0 

37 

0 100 

0 

0 (seldom 

less than 18) 

Maximum depth 

(m) 

220 

226 

200 (usually 

below 51) 261 

168 

543 

201 

111 

2514 

141 

800 (poorly 

known) 186 

186 

Figure 3 shows the range-in depth suggested by the 

fossil mollusks for each locality. Many of these assemblages contain only eurybathyal taxa that are not 

useful for paleobathymetric interpretations. The overlap of bathymetric data in table 4 indicates that the 

Narrow Cape Formation on Sitkinak Island accumulated in the outer neritic zone between depths of 

about 100 and 186m. Benthic foraminifers from four 

localities (table 2) suggest outer neritic depths of 100 

to 200m (Kristin McDougall, oral commun., 1979). 

WATER TEMPERATURE 

Analysis of the geographic ranges of modern 

analogs of mollusks from the Narrow Cape Formation on Sitkinak Island suggests that a cool-temperate marine climate existed at Sitkinak Island during 

the late Oligocene. The latitudinal ranges and marine 

climatic zones of some modern molluscan analogs 

shown in table 5 set limits on paleotemperature 

interpretation. 

The marine climate classification used here follows 

Hall (1964), who defined the cool-temperate marine 

climate as having water temperatures warming to 

10°C for only 3 or 4 months of the year and the mildtemperate marine climate as having water temperatures that reach near to, or slightly below, 15°C each 

year. 

TABLE 5.-Latitudinal ranges and marine climatic tolerances of 

living analogs of some mollusks from the Narrow Cape Formation on Sitkinak Island 

[Eurythermal taxa are omitted. The marine climate classification follows Hall (1964). Latitudinal ranges collated from Dall (1921), Keen (1937), Kotaka (1959), 

MacGinitie (1959), MacNeil (1965), Shikama (1967), Bernard (1970), Coan (1971), and Mann (1977)] 

Liocyma fluctuosa (Gould) .. Macoma (Macoma) calcarea (Gmelin) .............................................. . 

Macoma (Macoma) moesta moesta (Deshayes) ............................................ . Macoma (Macoma) moesta alaskana Dall ................ . Mya (Arenomya) ............ . 

Pitar .............. . Serripes ...................................................... . Ancistrolepis beringianus Dall .......... . 

Anc_ist~olepis eucosmius Dall .............. . Ber~ngiUS .................................................. . Buccinum pemphigus major Dall .. 

Calyptraea ............................................... . Musashia (Musashia) ....... . 

Turritella (large) (T. cooperi 

stock) ...................................................... . 

Turritella (large) (Neohaustator) ........ . 

48-72 

37-48?; 

48-72 

52-72 

48-60 

37-55; 

to 64? 19-57 

48-72 

54 range 

unknown 

44-57 

48-72 

23-56 

8-37 

~ 

"C 

Qi -~ bll ] r:: 

lXI ..c: .. exit! -a·;; g .s<"' 

-ge~ 

·E~~ 

j~~ 

?43-

58? 

33-

35.5 

?to 

46+ 

-a t) 

·a 

0 

~ 

1ii 

r:: 

.s 

Marine climate zones 

~ lXI 

-a 1ii t) Po ·a s 0 Cl) 

~ E-< 

!l E ::s lXI 

0 ~ 

-ICl) ~ 

lXI a; 

8. 1ii 

Po 

s s ~ ~ -a "C 0 ~ :§ 0 0 C) IXl 

- ~ 

-?- - ~ 

f.-~ 

I-f---?-

~f-­

? ~? 

Taxa suggesting water temperatures no warmer 

than the cool-temperate zone include (table 5): Liocyma cf. L. fluctuosa (Gould), Macoma cf. M. moesta 

moesta (Deshayes), M. cf. M. moesta alaskana Dall, 

?Serripes hamiltonensis (Clark), Ancistrolepis aff. A. 

beringianus Dall, ?Beringius sp., and Buccinum cf. B. 

pemphigus major Dall. Strauch (1968, 1971) reports 

that large specimens of Hiatella arctica (Linnaeus), 

which occur in the Sitkinak Island beds (pl. 1, fig. 21), 

reach such large size only in cold water (see Rowland 

and Hopkins, 1971, and Allison, 1973, for critiques of 
a: 

w 

CQ 

~ 

:::l 

z 

~ :::; 

5 

0 

..J 

..J 

iii 

(/) 

0 

LL.· 

c: 

0 

-~ 

Q) 

Ill 

0 

c. 

0 

1-

c: 

0 

-~ 

Q) 

Ill 

0 

E 

0 

::: 

0 

CQ 

c: 

~ 0 

c: 

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c: 

:;, 

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PALEOECOLOGY 

DEPTH, IN METERS 

INNER OUTER NERITIC ZONE I UPPERMOST BATHYAL 

NERITIC ZONE 

ZONE 0 0 

0 0 0 I N 

I I I I I I I I I I I I I I I I I I I I I I I I I I I 

M6590 0--168 

M6589 0--1554 

M6588 0-2208 

M6587 18-186 

M6586 18-186 

M6585 18-186 

M6499 37-141 

M6584 0--226 

M6583 --7--4 37-168 or 186 

M6582 0--1554 

M6581 37-2514 

M6580 100-800 

M6579 no data 

M6578 0-226 

M6577 37-261 

M6576 18-186 

M6575 37-1509 

M1489 ~ 100--111 

M6591 _j 7 0-1867 

M6592 1---i 100--111 

M6593 0-2309 

M7334 100-168 

M7335 0-168 

A1124 0--2208 

A1153 100--261 

A1154 18-186 

A1155 100-168 

A1156 0--261 

A1271 0--2978 

FIGURE 3.-Chart showing inferred paleobathymetry for each fossil locality, based on the fossil mollusks. 

7 

I 

0 

0 

M 

I 

... 

L 

.. 

L 

., 

~ 

.. 

... 

.. 

.. 

... 

.. 

... -.-

.... 

-.. 
8 MOLLUSCAN FAUNA FROM SITKINAK ISLAND, ALASKA 

Strauch's quantitative techniques). In addition, the 

presence of Macoma calcarea (Gmelin), Mya 

grewingki Makiyama, and Ancistrolepis aff. A. 

eucosmius Dall suggest that water temperature was 

no warmer than that of the mild-temperate climatic 

zone. 

Only one of the Sitkinak Island taxa, Musashia 

(Musashia) sp., has living analogs that live in water 

no cooler than the warm-temperate climatic zone 

along the present Asiatic coast. Several other 

Sitkinak Island mollusks that belong to extinct genera 

or subgenera suggest temperatures no cooler than the 

mild-temperate climatic zone: Echinophoria, Priscofusus, and Bruclarkia. Although their exact temperature tolerances are not known, these three taxa are 

usually found in warmer-water Tertiary faunas at 

TABLE 6.-0ccurrences of fossil mollusks in the Narrow Cape Formation, Sitkinak Island 

!In "Zoogeographic Affinity" column, NA =North American, A= Asiatic, E =endemic North Pacific, EPC =endemic, pre-circumboreal, C =cosmopolitan, U =unknown) 

$ 

'i: 

~ ~ 

u Localities in stratigraphic order 

:..c 

c. (from bottom of section, at left, to top of section, at right) ~ 

Taxa ~ 

~ :>£ 

0 

0 

N 

Bivalves: Acila (Acila) gettysburgensis (Reagan, 1909) _ -------- NA Acila sp. indet ................. -----··-··------------··········· ..... _________ U 

Chnocardium cf. C. makiyamae Kamada, 1962--- A Clmocardium cf. C. hannibali Keen, 1954 ............ ___ NA Clinocardium sp. indet _ __ __ __ __ _ U 

Crenella porterensis Weaver, 1912 _________________________ NA 

Cyclocardia cf. C. belogolouensis (IIyina, 1963)-- A Cyclocardia cf. C. subnipponica (Nagao, 1928) ..... __ A Cyclocardia cf. C. tokunagai (Yokoyama, 1924)-- A Cyclocardia cf. C. wajampolkensis (Ilyina, 1963) A 

Cyclocardia sp. indet ........ ___ _ ---------- U Hiatella arctica (Linnaeus, 1767) .... ..__________ C 

t2 

11:> 

CD 

:2 

Liocyma cf. L. fluctuosa (Gould, 1841)_ _______ .............. ER:: x 

Macoma (Macoma) calcarea (Gmelin, 1791) __________ m:; Macoma (Macoma) 1ncongrua (von Martens, 

1865) of Kanno (1971) ___ __ ..... _ __ _ __ .... ER:: Macoma (Macoma) cf. M. (M.) moesta moesta (Oeshayes, 1845). .. __ _ . .. .. _ ____ _ ..... ER:: Macoma (Macoma) cf. M. (M.) moesta alaskana 

Dall, 1900 ....... __ ------------------- ------------ .. _ _ E Macoma cf. M. optiua (Yokoyama, 1923) _ _ __ A 

CD 

t11:> 

CD 

:2 

t- ~ a> 0 00 N M t- t- 00 00 00 11:> 11:> 11:> ar. 11:> 11:> 11:> CD CD CD CD <0 CD <.0 

:2 :2 :2 :2 :2 :2 :2 

Macoma twmensis Clark, 1925 ----------------------.. --...... ___ NA cf. Macoma sp. indet _ U ?Macoma sp _____ ........ _ _ ___________ .................. _ _ ___ U 

Mya (?Arenomya)grewingki Makiyama, 1934.. A ?Mya sp ...... . .. ..... _ __ ________ ___ __ .... _ ..... __________ U 

Periploma (Aelga) besshoense (Yokoyama, 1924) A ? Periploma sp ..... _ ......... __________ ......... ___________________ ....... U 

Pitar (Katherinella) angusti{rons (Conrad, 1849) NA ?Serripes hamiltonensis (Clark, 1932) ............ _______ E 

Spisula cf. S. hannibali (Clark and Arnold, 1923) NA Spisula sp. indet.. ............ _____ ..................................... NA Gastropods: Ancistrolepis aff. A. beringianus Dall, 1919 _ E 

Anc~strolepis aff.,;4 .• ~ucosmius (Oall, 1891)__ E 

Anc1strolep!s sp. C .... U 

Ancistrolepis sp. indet . U ? Ancistrolepis sp . U 

?Beringius sp..... . .. .......... ........................ U 

Bruclarkia cf. B. andersoni (Wiedey, 1928) ...... _________ NA 

Bruclarkia sp indet ... ... . ............................. U Buccinum aff. B. kurodai Kanehara, 1937 ___ ... _ A 

Buccinum cf. B. pemphigus major Dall, 1919 ... A Buccinum sp ........... ____________ ....... ......... . ........... U 

Calyptraea cf. C. diegoana (Conrad, 1855). NA Echinophoria apta (Tegland, 1931) ...................... _ .. NA 

Epitonium (Nitidiscala) sp ........ ---------------------------........ U Musashia (Musashia) sp _______ .. _ .. _____________ .. ____ .. __ A 

Natica (Cryptonatica) clausa Broderip and Sowerby, 1829.. .. .................. ER:: Naticid indet _____ ... U 

Neptuneidae indet ________ .............................................. _ U 

Neuerita (Neuerita) washingtonensis (Weaver, 

1916)............. ... .... ..------------------ .............. NA Oenopota sp. indet.. ..................................... _ ....... . U 

Parasyrinx sp ______________ ...................................... .... U 

Polinices (Euspira) ramonensis (Clark, 1918) ___ NA Polinices (Euspira) cf. P. (E.) lincolnensis 

(Weaver, 1916) ............................... . ......... N A Priscofusus clarki Kanno, 1971 ... .......... E 

Priscofusus aff. P. stewarti (Tegland, 1933) ............. NA Turritella (Hataiella) cf. T. (H) chichibuensis 

Ida, 1952 .......................... .'........... .. ........ A 

Turri tel/a (Hataiella) sp.. U 

Cephalopod: Aturia angustata (Conrad, 1849) .......................... N A Scaphopod: 

Dentalium (Coccodentalium) cf. D. (C.) nunomae 

..,. a> 00 a> an ..,. <.0 <.0 

::E ::E 

Takeda, 1953, of Kanno (1971). A -- -- -- -- -- -- -- -- -- -- --

11:> CD t- 00 00 00 00 00 11:> 11:> 11:> 11:> <.0 <0 <.0 <.0 

::E ::E ::E ::E 

Localities with stratigraphic 

position unknown 

a> 0 a> o; N iii ..,. 11:> ..,. M ..,. 11:> 

00 a> ~ a> M M :::! !S !S !S 11:> 11:> 11:> 11:> 11:> M M <.0 <.0 <.0 <.0 <.0 t- t-

:2 ::E :2 :2 ::E ::E ::E ::E <: <: <: <: 

CD ;::: !S N 

<: <: 
REFERENCES CITED 9 

more southerly latitudes than that of Sitkinak Island. 

Large turritellids were restricted to warmer waters in 

most of the Americas during the Cenozoic but extend 

into the cool-temperate zone in Asia today. The 

extinct subgenus Turritella (Hataiella) also occurs in 

the Yakataga Formation of the northeastern Gulf of 

Alaska in molluscan assemblages that appear to 

represent temperatures near the mild-temperate to 

cool-temperate boundary (Allison, 1978). 

Cool-temperate faunal elements in the Sitkinak 

Island beds appear to us to be much more significant 

indicators of the marine climate than the occurrence 

of the warmer-water taxon Musashia. Although 

Musashia (Musashia) is known today only from 

regions with outer tropical and warm-temperate surface waters in Asia, it appears to dwell only in deeper, 

and therefore colder, water. Thus its occurrence in the 

Sitkinak Island Oligocene fauna may be compatible 

with inferred cool-temperate surface waters. 

The relatively uniform distribution of mollusks 

throughout the stratigraphic section suggests that 

water temperatures remained uniform during the 

deposition of the formation. 

The inferred marine climate of the fauna from the 

Narrow Cape Formation on Sitkinak Island differs 

significantly from that of the fauna of the type 

Narrow Cape Formation on Kodiak Island. The presence of Dosinia, Securella, Anadaara (Anadara), and 

Ficus in the type Narrow Cape Formation implies a 

warm-temperate or outer-tropical marine climate 

(Addicott, 1969; Allison, 1978). 

PALEOZOOGEOGRAPHIC AFFINITIES 

Thirty-nine of the 58 entries on the faunal checklist 

(table 6) are suitable for evaluation of zoogeographic 

affinities. Among these 39 taxa, 38 percent have 

North American affinities, 33 percent have Asiatic 

affinities, and 26 percent are endemic to the highlatitude North Pacific. Thirteen percent of the 

Sitkinak Island fauna (included above in the endemics) is composed of "pre-circum boreal" taxa (Allison, 

1978); these species apparently gave rise to taxa that 

later passed through Bering Strait to the Arctic 

Ocean, where some achieved circumboreal distribution. Hiatella arctica (Linnaeus, 1767), a cosmopolitan bivalve that constitutes 3 percent of the fauna, is 

the most abundant species in the collections. The 

zoogeographic affinities of each taxon are given in 

table 6. 

The co-occurrence in the Sitkinak Island strata of 

molluscan taxa from these three zoogeographically 

distinct areas greatly enhances the potential of this 

fauna for making chronostratigraphic correlations 

along the North Pacific margin. 

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Addicott, W. 0., 1969, Tertiary climatic change in the marginal 

northeastern Pacific Ocean: Science, v. 165, p. 583-586, 3 

text-figs. 

__ 1976a, New molluscan assemblages from the upper member 

of the Twin River Formation, western Washington: significance inN eo gene chronostratigraphy: U.S. Geological Survey 

Journal of Research, v. 4, no. 4, p. 437-447, 7 figs. 

__ 1976b, Neogene molluscan stages of Oregon and Washington: Society of Economic Paleontologists and Mineralogists, 

Pacific Section, Neogene Symposium, San Francisco, Calif., 

1976, p. 95-115, 5 pis., 6 text-figs., 1 table. 

Allison, R. C., 1973, Marine paleoclimatology and paleoecology of 

a Pleistocene invertebrate fauna from Amchitka Island, 

Aleutian Islands, Alaska: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 13, p. 15-48, 3 text-figs., 9 tables. 

__ 1976, Late Oligocene through Pleistocene molluscan faunas 

in the Gulf of Alaska region: International Congress on 

Pacific Neogene Stratigraphy, 1st, Tokyo, Japan, May 16-21, 

1976, Abstracts of Papers, p. 10-13. Reprinted 1977 in Congress Proceedings, p. 313-316, 1 text fig., 1 table. 

__ 1978, Late Oligocene through Pleistocene molluscan faunas 

in the Gulf of Alaska region: Veliger, v. 21, no. 2, p. 171-188, 2 

text-figs., 2 tables. 

Armentrout, J. M., 1975, Molluscan biostratigraphy ofthe Lincoln 

Creek Formation, southwest Washington: Society of Economic Paleontologists and Mineralogists, Pacific Section, Paleogene Symposium and selected technical papers, Long Beach, 

Calif., 1975, p. 14-48, 7 text-figs. 

Bernard, F. R., 1970, A distributional checklist of the marine 

molluscs of British Columbia: based on faunistic surveys 

since 1950: Syesis, v. 3, p. 75-94, 1 text-fig. 

Blow, W. H., 1969, Late middle Eocene to Recent planktonic 

foraminiferal biostratigraphy: International Conference on 

Planktonic Microfossils, 1st, Geneva 1967, Proceedings, p. 

199-422. 

Coan, E. V., 1971, The northwest American Tellinidae: Veliger, 

Supplement, v. 14, p. 1-63, 12 pis., 30 text-figs., 8 tables. 

Dall, W. H., 1896, Report on coal and lignite of Alaska: U.S. 

Geological Survey 17th Annual Report, pt. 1, p. 763-908, pls. 

48-58. 

__ 1921, Summary of the marine shell bearing mollusks of the 

northwest coast of America, from San Diego, California, to 

the polar sea, mostly contained in the collection of the United 

States National Museum, with illustrations of hitherto 

unfigured species: U.S. National Museum Bulletin, v. 112, p. 

1-217, pis. 1-22. 

Durham, J. W., 1944, Megafauna} zones of the Oligocene of 

northwestern Washington: University of California Publications, DepartmentofGeological Sciences Bulletin, v. 27, no. 5, 

p. 101-212, pls. 13-18. 

Gladenkov, Y. B., 1980, Stratigraphy of marine Paleogene and 

Neogene of northeast Asia (Chukotka, Kamchatka, Sakhalin): American Association of Petroleum Geologists Bulletin, 

v. 64, no. 7, p. 1087-1093, text-figs. 1-3. 

Hall, C. A., Jr., 1964, Shallow-water marine climates and molluscan provinc~s: Ecology, v. 45, no. 2, p. 226-234, 6 text-figs., 2 

tables. 

lkebe, N., Takayanagi, Y., Chiji, M., and Chinzei, K., 1972, 

Neogene biostratigraphy and radiometric time scale of Japan 

-an attempt at intercontinental correlation: Pacific Geology, 

v. 4, p. 39-78, text-figs. 1-8, 2 tables. 

Ilyina, A. P., 1963, Mollyuski Neogena Kamchatki [Neogene 

mollusks of Kamchatka]: V sesoyuznogo Neftyanogo N auchno-
10 MOLLUSCAN FAUNA FROM SITKINAK ISLAND, ALASKA 

Issledovatel'skogo Geologo-Razvedoch~ogo Instituta 

(VNIGRI) Trudy, v. 202, p. 1-242, pls. 1-54, tables 1-3. 

Kamada, Y., 1962, Tertiary marine Mollusca from the Joban CoalField, Japan: Palaeontological Society of Japan Special 

Paper 8, p. 1-187, pls. 1-21, 3 text-figs., 2 tables. 

Kanno, S., 1960, Part II, Paleontology, in Arai, J., and Kanno, S., 

The Tertiary system of the Chichibu Basin, Saitama Prefecture, central Japan: Ueno, Japan, Japan Society for the 

Promotion of Science, p. 123-396, pls. 31-51, text-figs. 21-26, 

tables 5-19, 5 maps. 

__ 1971, Tertiary molluscan fa una from tpe Y aka tag a District 

and adjacent areas of southern Alaska: Palaeontological 

Society of Japan Special Paper 16, 154 p., 18 pls. 

Keen, A.M., 1937, An abridged checklist and bibliography of west 

North American marine Mollusca: Stanford, Calif., Stanford 

University Press, p. 1-87. 

Kotaka, T., 1959, The Cenozoic Turritellidae of Japan: Science 

Reports of the Tohoku University, 2d ser. (Geology), v. 31, no. 

2, p. 1-135, pls. 1-15, 12 text figs., 3 tables. 

MacGinitie, N., 1959, Marine Mollusca of Point Barrow, Alaska: 

U.S. National Museum Proceedings, v. 109, no. 3412, p. 

59-208, pls. 1-27. 

MacNeil, F. S., 1965, Evolution and distribution of the genus Mya, 

and Tertiary migrations of Mollusca: U.S. Geological Survey 

Professional Paper 483-G, p. Gl-G51, 3 text-figs., pls. 1-11. 

Mann, D. M., 1977, Shelled benthic fauna of the eastern Chukchi 

Sea: U.S. Geological Survey Open-File Report 77-672, p. 

1-112, text-figs. 1-3, distribution maps, 2 tables, appendix. 

Menner, V. V., Baranova, Yu. P., and Zhidkova, L. S., 1977, 

Neogene of the northeastern USSR (Kolyma region, Kamchatka, and Sakhalin): International Congress on Pacific 

Neogene Stratigraphy, 1st, Tokyo, Japan, May 16-21, 1976, p. 

83-88, 2 tables. 

Moore, G. W., 1967, Preliminary geologic map of Kodiak Island 

and vicinity, Alaska: U.S. Geological Survey Open-File Report 

OF -271, map. 

__ 1969, New formations on Kodiak and adjacent islands, 

Alaska: U.S. Geological Survey Bulletin 1274-A, p. A27-A35, 

1 text-fig. 

Nilsen, T. H., and Moore, G. W., 1979, Reconnaissance study of 

Upper Cretaceous to Miocene stratigraphic units and sedimentary facies, Kodiak and adjacent islands, Alaska: U.S. Geological Survey Professional Paper 1093, p. 1-34, figs. 1-18. 

Rau, W. W., 1964, Foraminifera from the northern Olympic 

Peninsula, Washington: U.S. Geological Survey Professional 

Paper 374-G, p. G1-G33, pls. 1-7. 

Rowland, R. W., and Hopkins, D. M., 1971, Comments on the use of 

Hiatella arctica for determining Cenozoic sea temperature: 

Palaeogeography, Palaeoclimatology, Palaeoecology, v. 9, 

no. 1, p. 59-61. 

Shikama, T., 1967, System and evolution of Japanese fulgorarid 

Gastropoda: Yokohama National University Science Reports, 

sec. II, no. 13, p. 23-132, pls. 1-17, 26 text-figs., 40 tables. 

Smith, P. S., 1939, Areal geology of Alaska: U.S. Geological 

Survey Professional Paper 192, 100 p. 

Snavely, P. D., Jr., Niem, A. R., and Pearl, J. E., 1978, Twin River 

Group (upper Eocene to lower Miocene)-defined to include 

the Hoko River, Makah, and Pysht Formations, Clallam 

County, Washington: U.S. Geological Survey Bulletin 1457-A, 

p. A111-A120. 

Strauch, F., 1968, Determination of Cenozoic sea-temperature 

using Hiatella arctica (Linne): Palaeogeography, Palaeoclimatology, Palaeoecology, v. 5, p. 213-233. 

__ 1971, Some remarks on Hiatella as an indicator of sea 

temperatures: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 9, no. 1, p. 62-64. 

Zhidkova, L. S., Bevz, V. E., Ilyina, A. P., Krishtofovich, I.;, V., 

Neverova, T. L., Savitskii, V. 0., and Sheremet'eva, G. N., 

1972, Atlas neogenovykh molliuskov Kuril'skikh Ostrovov 

[Atlas of the Neogene mollusks of the Kuril Islands]: 

Akademiya N auk SSSR Sibirskoye Otdeleniye, Sakhalinskiy 

Kompleksnyy Nauchno-Issledovatel'skiy Institut Trudy, p. 

6-162, 68 pls., illus., charts, map. 

Zhidkova, L. S., Kuzina, I. N., Lautenshlager, F. G., and Popova, 

L.A., 1968, Atlas molliuskov verkhnogo Miotsena i Pliotsena 

Sakhalina [Atlas of the mollusks of the upper Miocene and 

Pliocene of Sakhalin]: Akademiya Nauk SSSR Sibirskoye 

Otdeleniye, Sakhalinskiy Kompleksnyy Nauchno-Issledovatel'skiy Institut Trudy, p. 3-175, pls. 1-50, illus. 
Acila (Acila) gettysburgensis, 4, 8; pl. 

sp. indet., 8 

(Aci/a) gettysburgensis, Acila, 4, 8; pl. 

adelaidana, Bolivina marginata, 4 

(Aelga) besshoense, Periploma, 5, 8; pl. 2 

Age, 5 

alaskans, Macoma (Macoma) moesta, 6, 8 

albaria, Spisula, 4 

Anadara (Anadara), 9 

(Anadara), Anadara, 9 

Ancistrolepis, 6 

beringianus, 6, 8; pl. 2 

eucosmius, 6, 8; pl. 2 

sp. C, 8; pl. 2 

sp. indet., 8 

andersoni, Bruclar_kia, 4, 8; pl. 2 

angustata, Aturia, 8 

anl(usttfrons, Pilar (Katherinella), 4, 8; pl. 2 

apta, Echinophoria, 8; pl. 3 

Zone, Echinophoria, 4 

arctica, Hiatella, 6, 8 

(Arenomya) grewingki, Mya, 4, 5, 6, 8 

Mya, 6 

Asagai Formation, Japan, 5 

Aturia angustata, 8 

Bathysiphon sanctaecrucis, 

sp., 4 

belogolovensis, Cyclocardia, 5, 8 

beringianus, Ancistrolepis, 6, 8; pl. 2 

Beringius sp., 6, 8; pl. 2 

besshoense, Periploma (Aelga), 5, 8; pl. 

Bolivina marginata adelaidana, 4 

Bruclarkia, 8 

andersoni, 4, 8; pl. 2 

sp. indet., 8 

Buccella mansfieldi oregonensis, 

Buccinum kurodai, 5, 8; pl. 2 

pemphigus major, 6, 8; pl. 2 

sp., 8; pl. 2 

calcarea, Macoma (Macoma), 4, 6, 8 

Ca/yptraea, 6 

diegoana, 4, 8; pl. 3 

Cassidulina crassipunctata, 

cephalopod, 3, 8 

chichibuensis, Turritella (Hataiella), 4, 5, 8; pl. 3 

Cibicides, 4 

Cibicides elmaensis, 4 

sp., 4 

clarki, Priscofusus, 4, 8; pl. 2 

clausa, Natica (Cryptonatica), 4, 8; pl. 3 

Clinocardium, 6 

hannibali, 8; pl. 1 

makiyamae, 4, 5, 8; pl. 1 

sp. indet., 8 

(Coccodentalium) nunomae, Dentalium, 5, 8 

conica, Pseudonodosaria, 4 

consobrina, Dentalina, 4 

Correlation, 5 

crassipunctata, Cassidulina, 

Crenella porterensis, 4, 8 

(Cryptonatica) clausa, Natica, 4, 8; pl. 3 

Cyclammina pacifica, 4 

sp., 4 

Cyclocardia belogolovensis, 5, 8 

subnipponica, 4, 5, 8 

tokunagai, 4, 5, 8; pl. 1 

wajampolkensis, 5, 8; pl. 1 

sp. indet., 8 

Dentalina consobrina, 4 

sp., 4 

Dentalium (Coccodentalium) nunomae, 5, 8 

diegoana, Calyptraea, 4, 8; pl. 3 

Dosinia, 9 

INDEX 

[Italic page numbers indicate major references] 

Echinophorw, 8 

apta, 4, 8; pl. 3 

apta Zone, 1, 4, 5 

elmaensis, Cibicides, 4 

Elphidium sp., 4 

Entosolenia sp., 4 

Epitonium (Nittdiscala) sp., 8; pl. 3 

Eponides mexicanus, 4 

sp., 4 

eucosmius, Anc1stro/epis, 6, 8; pl. 2 

(Euspira) lincolnensis, Polinices, 4, 

ramonensis, Polinices, 4, 8; pl. 3 

Faunal composition, 2 

Foraminifers, 4 

Fusinus, 6 

Gakhinian Stage, 

gastropods, 4, 8 

gettysburgens1s, Acila (Acila), 4, 8; pl. 1 

grewingk1, Mya (Arenomya), 4, 5, 6, 8 

hamiltonensis, Serripes, 4, 6, 8; pl. 

hannibali, Clinocardium, 8; pl. 1 

Spisula, 4, 8; pl. 2 

Haplaphragmoides sp. A, 

spp. indet., 4 

(Hataiella) chichibuensis, Turritella, 4, 5, 8; pl. 3 

Turritella, 8 

Hiatella arctica, 6, 8, 9 

in'congrua, Macoma (Macoma), 4, 6, 8 

Jwaki Formation, Japan, 4 

Juanian Stage, 1, 4, 5 

(Katherinella) angustifrons, Pitar, 4, 8; pl.2 

kurodai, Buccinum, 5, 8; pl. 2 

lincolnensis, Polinices (Euspira), 4, 8 

Liocyma fluctuosa, 6, 8 

Luisian Stage, 6 

Machigarian Stage, 5 

Macoma calcarea, 4 

incongrua, 4 

moesta moesta, 4 

optiva, 5, 8; pl. 1 

twmensis, 4, 8 

sp., 8 

· (Macoma) calcarea, 4, 6, 8 

incongrua, 4, 6, 8 

moesta alaskana, 6, 8 

moesta, 4, 6, 8 

(Macoma) calcarea, Macoma, 4, 6, 8 

incongrua, Macoma, 4, 6, 8 

moesta alaskans, Macoma, 6, 8 

moesta, Macoma, 4, 6, 8 

major, Buccinum pemphigus, 6, 8; pl. 

makiyamae, Clinocardium, 4, 5, 8; pl. 

mansfieldi oregonensis, Buccella, 4 

marginata adelaidana, Bolivina, 4 

Marie Formation, U.S.S.R. 5 

Melonis pompilioides, 4 

mexicanus, Eponides, 4 

moesta alaskana, Macoma (Macoma), 6, 8 

Macoma (Macoma) moesta, 4, 6, 8 

moesta, Macoma (Macoma), 4, 6, 8 

mollusks, 5, 6 

Musashia, 6 

(Musashia) sp., 6, 8; pl. 3 

(Musashia) sp., Musashia, 6, 8; pl. 3 

Mya, 6 

grewingki, 4 

(Arenomya), 6 

grewingki, 4, 5, 6, 8 

Narrow Cape Formation, Kodiak Island, 1, 4, 5, 6 

Natica clausa, 4 

(Cryptonatica) clausa, 4, 8; pl. 3 

Nenokami Sandstone, Japan, 5 

(Neohaustator), Turritella, 6 

Neverita washingtonensis, 4 

(Neverita) washingtonensis, 4, 8 

(Neverita) washingtonensis, Nel'enta, 4, 8 

Newportian molluscan Stage, 6 

Nissakutan Formation, U.S.S.R. 5 

(Nitidiscala), ·Ep1tonium, 8, pl. 3 

Nonion planatum, 4 

nunomae, Denta/ium (Coccodentalium), 5, 8 

Oenopota sp. indet., 8 

optwa, Macoma, 5, 8; pl. 1 

oregonensis, Buccella mansfieldi, 

Ostracods, 4 

pacifica, Cyclammma, 

Paleoecology, 6 

Paleozoogeographic affinities, 9 

Parasyrmx sp., 8; pl. 2 

Pelecypods, 4 

pemphigus major, Buccinum, 6, 8; pl. 2 

Periploma (Aelga) besshoense, 5, 8; pl. 2 

sp., 8 

Pillarian molluscan Stage, 6 

Pitar, 6 

angustifrons, 4 

(Katherinella) angustifrons, 4, 8; pl.2 

planatum, Nonion, 4 

Polinices (Euspira) lincolnensis, 4 

(Euspira) ramonensis, 4, 8; pl. 3 

pompilioides, Melonis, 4 

Poronai Formation, Japan, 5 

porterensis, Crenella, 4, 8 

Poul Creek Formation, 4 

Priscofusus, 6, 8 

clarki, 4, 8; pl. 2 

stewarti, 4, 8; pl. 2 

Pseudonodosaria conica, 

Pysht Formation, 4, 5 

Radiolaria, 4 

ramonensis, Polinices (Euspira), 4, 8; pl. 3 

References cited, 9 

sanctaecrucis, Bathysiphon, 4 

Saucesian benthic foraminiferal Stage, 6 

scaphopod, 4, 8 

Securella, 9 

Serripes, 6 

hamiltonensis, 4, 6, 8; pl. 2 

Sooke Formation, 4 

Spisula, 6 

albaria, 4 

hannibali, 4 

sp. indet., 8 

stewarti, Priscofusus, 4, 8; pl.2 

subnipponica, Cyclocardia, 4, 5, 8 

(T. cooperi stock), Turritella, 6 

tokunagai, Cyclocardia, 4, 5, 8; pl. 1 

Trochammina sp., 4 

Turritella, 6 

chichibuensis, 4 

(Hataiella) chichibuensis, 4, 5, 8; pl. 3 

sp., 8 

(Neohaustator), 6 

( T. coo peri stock), 6 

Twin River Group, 4, 5 

twinensis, Macoma, 4, 8 

Ushikubitoge Formation, Japan, 5 

wajampolkensis, Cyclocardia, 5, 8; pl. 1 

washingtonensis, Neuerita (Neuertta), 4, 8 

Water depth, 6 

Water temperature, 6 

11 

PLATESl-3 

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 

All figured specimens are from the Narrow Cape Formation, Sitkinak Island 

(All figures Xl, unless noted otherwise) 

FIGURES 1. Acila (Acila) gettysburgensis (Reagan, 1909). Univ. Alaska UA2513, UA loc. A-1156. Length 17.3 mm, height 12.5 · 

mm (X2). 

2. Clinocardium cf. C. makiyamae Kamada, 1962. USNM 265810, USGS loc. M6578. Length 37.5 mm, height 33.3 mm. 

3, 4. Clinocardium cf. C. hannibali Keen, 1954. USNM 265811, USGS loc. M6592. Length 30.8 mm, height 28.6 mm. 

5, 6. Crenella porterenis Weaver, 1912. USNM 265826, USGS loc. M6585. Length 11.9 mm, height 14.9 mm. 

7, 8. Cyclocardia cf. C. belogolovensis (Ilyina, 1963). USNM 265812, USGS loc. M6499. Length 29.5 mm, height 30.3 mm. 

9. Cyclocardia cf. C. belogolovenis (Ilyina, 1963). Univ. Alaska UA2514, UA loc. A-1155. Length 28.1mm, 

height 30.8 mm. 

10. Cyclocardia cf. C. subnipponica (Nagao, 1928). USNM 265813, USGS loc. M1489. Length 34.7 mm, height 28.2 mm. 

11, 13. Cyclocardia cf. C. tokunagai (Yokoyama, 1924). USNM 265815, USGS loc. M6499. Length 21.7 mm, height 18.8 mm. 

12. Cyclocardia cf. C. tokunagai (Yokoyama, 1924). USNM 265814, USGS loc. M6499. Length 22.9 mm, height 22.5 mm. 

14, 15. Cyclocardia cf. C. tokunagai (Yokoyama, 1924). Univ. Alaska UA2516, UA loc. A-1155: Length 24.7 mm, 

height 21.4 mm. 

16, 17. Cyclocardia cf. C wajampolkensis (Ilyina, 1963). USNM 265816, USGS loc. M1489. Length 25.7 mm, height 20.0 mm. 

18. Cyclocardia cf. C. wajampolkensis (Ilyina, 1963). Univ. Alaska UA2517, UA loc. A-1155. Length 22.5 mm, 

height 23.0 mm. 

19, 20. Cyclocardia cf. C. wajampolkensis (Ilyina, 1963). Univ. Alaska UA2515, UA loc. A-1155. Length 29.6 mm, 

height 25.9 mm. 

21. Hiatella arctica (Linnaeus, 1767). USNM 265817, USGS loc. M1489. Length 42.4 mm, height 20.3 mm. 

22, 23. Hiatella arctica (Linneaus, 1767). USNM 265818, USGS loc. M6499. Length 26.0 mm, height 13.2 mm. 

24, 25. Liocyma cf. L. fluctuosa (Gould, 1841). USNM 265819, USGS loc. M6575. Length 11.0 mm, height 9.mm (Xll/2). 

26. Macoma (Macoma) incongrua (von Martens, 1865) of Kanno (1971). USNM 265820, USGS loc. M6499. Length 

20.0 mm, height 17.1 mm. 

27, 28. Macoma (Macoma) cf. M. (M.) moesta moesta (Deshayes, 1854). USNM 265821, USGS loc. M6578. Length 20.7 mm, 

height 15.2 mm. 

29. Macoma twinensis Clark, 1925. USNM 265824, USGS loc. M6585. Length 28.7 mm, height 22.3 mm. 

30, 31. Macoma (Macoma) cf. M. (M.) moesta alaskana Dall, 1900. USNM 265823, USGS loc. M6576. Length 18.5 mm, 

height 10.3 mm (X11f2). 

32. Macoma cf. M.·optiva (Yokoyama, 1923). Univ. Alaska UA2518, UA loc. A-1156. Length 17.0 mm, height 15.9 mm. 

33. Mya (?Arenomya)grewingki Makiyama, 1934. USNM 265850, USGS loc. M7334. Length 75.5 mm, height 48.7 mm. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1233 PLATE 1 

3 4 

2 

5 6 7 8 9 

11 

14 15 

10 

12 13 

19 20 

16 17 18 

24 

22 23 

26 

21 

25 

29 

27 28 

30 31 32 33 

ACILA, CLINOCARDIUM, CRENELLA, CYCLOCARDIA, HIATELLA, LIOCYMA, MACOMA, MYA 
PLATE2 

All figured specimens are from the Narrow Cape Formation, Sitkinak Island 

(All figures Xl, unless noted otherwise) 

FIGURES 1. Periploma (Aelga) besshoense (Yokoyama, 1924). USNM 265828, USGS loc. M6575. Length 51.6 mm, height 42.3 mm. 

2. Periploma (Aelga) besshoense (Yokoyama, 1924). USNM 265825, USGS loc. M6582. Length 31.3 mm, height 21.8 mm. 

3, 4. Pitar (Katherinella) angustifrons (Conrad, 1849). USNM 265829, USGS loc. M6585. Length 40.3 mm, height 34.4 mm. 

5. ?Serripes hamiltonensis (Clark, 1932). USNM 265831, USGS loc. M1489. Length 34.0 mm, height 31.8 mm. 

6, 7. Ancistrolepis aff. A. beringianus Dall, 1919. USNM 265833, USGS loc. M1489. Height 41.2 mm, diameter 26.0 mm. 

8. Spisula cf. S. hannibali (Clark and Arnold, 1923). USNM 265827, USGS loc. M1489. Length 69.3 mm, height 58.4 mm. 

9. Ancistrolepis sp. "C". USNM 265835, USGS loc. M6592. Height 38. 5mm, diameter 24.3 mm. 

10. Ancistrolepis aff. A. eucosmius (Dall, 1891). USNM 265834, USGS loc. M1489. Height 28.3 mm, diameter 18.6 mm. 

11, 12. Bruclarkia cf. B. andersoni (Wiedey, 1928). USNM 265836, USGS loc. M6499. Height 40.7 mm, diameter 23.2 mm. 

13. ? Beringius sp. USNM 265830, USGS loc. M1489. Height 38.1 mm, diameter 19.6 mm. 

14, 15. Buccinum cf. B. pemphigus major Dall, 1919. USNM 265839, USGS loc. M6592. Height 25.5 mm, diameter 20.3 mm. 

16, 17. Buccinum aff. B. kurodai Kanehara, 1937. USNM 265837, USGS loc. M6592. Height 35.0 mm, diameter 26.0 mm. 

18, 19. Parasyrinx sp. USNM 265843, USGS loc. M6499. Height 33.0 mm, diameter 9.5 mm. 

20, 21. Buccinum aff. B. kurodai Kanehara, 1937. Univ. Alaska UA2510, UA loc. A-1153. Height 74.3 mm, diameter 42.3 mm. 

22. Buccinum sp. USNM 265838, USGS loc. M1489. Height 43.2 mm, diameter 24.3 mm. 

23. Priscofusus aff. P. stewarti (Tegland, 1933). USNM 265840, USGS loc. M6585. Height 17.4 mm, diameter 9.5 mm. 

24, 25. Prisco{usus clarki Kanno, 1971. USNM 265844, USGS loc. M1489. Height 39.0 mm, diameter 16.0 mm. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1233 PLATE 2 

3 4 

2 

5 

6 7 

10 

9 

1 1 12 

15 

16 22 

18 

19 

PERIPLOMA, PITAR, ?SERRIPES, ANCISTROLEPIS, SPISULA, BRUCLARKIA, ?BERING/US, 

BUCCINUM, PARASYRINX, PRISCOFUSUS 

23 
PLATE3 

All figured specimens are from the Narrow Cape Formation, Sitkinak Island 

(All figures Xl, unless noted otherwise) 

FIGURES 1. Echinophoria apta (Tegland, 1931). USNM 265842, USGS loc. M1489. Height 49.0 mm, diameter 43.0 mm. 

2, 3. Calyptraea cf. C. diegoana (Conrad, 1855). USNM 265848, USGS loc. M6499. Length 14.7 mm, height 4.4 mm, width 

11. 1 mm (X2). 

4. Turritella (Hataiella) cf. T. (H.) chichibuensis Ida, 1951. USNM 265832, USGS loc. M6499. Height 32.8 mm, diameter 

10.7 mm. 

5, 6, 7. Epitonium (Nitidiscala) sp. USNM 265849, USGS loc. M7334. Height 22.0 mm, diameter ll.8 mm (X1 1/2). 

8, 14. Musashia, (Musashia) sp. Univ. Alaska UA25ll, UA loc. A-ll55. Height 85.0 mm, diameter 50.1 mm. 

9. Natica (Cryptonatica) clausa Broderip and Sowerby, 1829. USNM 265853, USGS loc. M6592. Height 31.9 mm, 

diameter 28.0 mm. 

10. Natica (Cryptonatica) clausa Broderip and Sowerby, 1829. USNM 265846, USGS loc. M6587. Height 26.3 mm, 

diameter 26.6 mm. 

11. Polinices (Euspira) ramonensis (Clark, 1918). USNM 265847, USGS loc. M6585. Height 13.6 mm, diameter 12.8 mm 

(X2). 

12, 13. Musashia (Musashia) sp. USNM 265845, USGS loc. M6592. Height 93.3 mm, diameter 38.4 mm. 

15. Musashia (Musashia) sp. USNM 265841, USGS loc. M6580. Height 43.5 mm, diameter 20.5 mm. 

16, 17. Musashia (Musashia) sp. Univ. Alaska UA2512, UA loc. A-ll53. Height 97.3 mm, diameter 51.0 mm. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1233 PLATE 3 

2 

6 

4 5 7 

3 

9 

10 

13 

8 

11 

14 15 16 17 

ECHINOPHORIA, CALYPTRAEA, TURRITELLA, EPITONIUM, MUSASHIA, NATICA, POLINICES 
GPO 587-o41/23 
Allison and Marincovich-LATE OLIGOCENE OR EARLIEST MIOCENE MOLLUSCAN FAUNA FROM SITKINAK ISLAND, ALASKA-Geological Survey Professional Paper 1233 

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