Molluscan paleontology of the 

lower Miocene Clallam Formation, 

northwestern Washington 

By WARREN 0. ADDICOTT 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 976 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1976 
UNITED STATES DEPARTMENT OF THE INTERIOR 

THOMAS S. KLEPPE, Srrrrtary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Dirrrtor 

Library of Congress Cataloging in Publication Data 

Addicott, Warren 0 . 

Molluscan paleontology of the lower Miocene Clallam Formation , northwestern Washington. 

(Geological Survey Professional Paper 976) 

Bibliography: p. 36-39. 

Includes index. 

Supt. of Docs. no.: I 19.16:976 

1. Mollusks, Fossil. 2. Paleontology - Miocene. 3. Paleontology - Washington (State) I. Title. II. Series: United States 

Geological Survey Professional Paper 976. 

QE80l.A2 564'.09797'9 76-608062 

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

Washington, D.C. 20402 

Stock Number 024-001-02871-9 
CONTENTS 

Page Page 

Abstract 1 Molluscan paleontology-Continued 

Introduction ---------------------------------------------- 1 Pelecypods -------------------------------------------- 27 

~uculidae ---------------------------------------- 27 

~uculanidae - ---- --------------------------------- 27 

Acknowledgments______________________________________ 3 

Previous faunal studies ------------------------------------ 3 

Molluscan fauna ------------------------------------------ 4 Solemyidae __ _ _ __ _ _ _ __ ___ __ _ _ _ _ __ __ ______ __ ___ _____ 28 

Biostratigraphy __________________________________ ____ ______ 6 Arcidae _ _ ____ __ __ _ __ ___ __ _ __ _ __ __ __ ____ __ __ _ _ _ ___ 28 

Introduction _ _ __ _ _ _ _ _ _ _ _ __ _ _ _ _ __ __ __ __ _ _ __ _ _ __ _ _ _ _ _ _ _ _ 6 (}]ycymerididae __ _ _ _ __ __ _ __ _ _ _ _ __ __ __ ____ ____ ____ __ 28 

Clallam Formation ------------------------------------ 6 Mytilidae_ _ _ _ __ __ _ _ __ __ _ _ _ ___ __ _ __ _ _ _ __ __ ___ _ __ _ _ _ _ 28 

Provincial chronostratigraphy ------------------------------ 12 

Age and correlation------------------------------------ 12 

Pillarian Stage ---------------------------------------- 18 

Paleoecology - --------------------------------------------- 18 

Pectinidae _ _ ___ _ __ _ _ _ _ _ __ _ __ ___ _ _ _ _ _ __ ___ _ __ _ _ _ ___ 29 

Lucinidae ---------------------------------------- 30 

Thyasiridae __ ------------------------------------ 30 

Ungulinidae _ __ _ _ _ _ __ __ _ ___ __ _ __ ___ __ ___ _ _ _ ___ _____ 30 

Bathymetry - - ---------------------------------------- 18 

Paleoclimate ------------------------------------------ 19 

Molluscan paleontology ----------------- ---- --- ------------ 20 

Carditidae __ _ _ __ __ ___ _____ __ _ __ ___ ___ __ _ __ _ _ __ __ __ 30 

Cardiidae __ ___ _ __ _ __ _ __ __ _ _ _ __ _ ____ _ __ ___ _____ _ __ 30 

Mactridae _ _ __ ___ _ __ __ __ _ ___ __ __ _ __ __ _ __ ____ __ __ __ 31 

(}astropods ~----------- ----------------------------- 21 

Turritellidae _ _ __ __ _ _ __ _ _ _ _ __ _ __ _ _ __ _ _ _ __ _ _ __ __ _ _ _ _ 21 

Solenidae ________________ ___________ _____ ------ __ _ _ 31 

Tellinidae _ _ _ _ _ ____ __ ___ __ _ __ _ __ __ _ __ _____ ____ __ __ 31 

PLATE 

Epi toniidae __ _ _ __ __ _ _ __ _ _ _ _ _ _ __ __ _ _ _ _ ___ _ __ __ __ _ _ _ _ 21 

Calyptraeidae -------- ---------------------------- 21 ~aticidae __ ______ __ __ _____ ____ ____________________ 22 

Cassididae ------------- --------------------- - ----- 22 

Ficidae ____________ _______________________ __ _______ 23 

M uricidae _ _ __ _ _ _ _ __ _ __ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ ___ __ _ _ _ _ _ 23 

~eptuneidae ---------- ---------- -- ---------------- 23 

Fusinidae ---------------------------------------- 24 

"olutidae ---------------------------------------- 25 

Cancellariidae __ __ _ __ __ _ __ _ _ _ _ _ _ __ _ _ _ _ __ _ _ _ _ _ _ __ _ _ 25 

Turridae ------------------ ------------------------ 26 

"eneridae __ _ _ __ __ _ _ _ _ _ _ __ ____ __ _ _ _ __ _ __ ___ _ __ __ _ _ 33 

Hiatellidae _ _ _ _ ___ __ _ _ __ _ __ _ _____ __ _ _ _ ___ _____ _ __ __ 34 

Thraciidae ------------- --------------------------- 34 

Cephalopods ______ ------------ ------------------------ 34 

Hercoglossidae __ __ _ __ _ _ _ __ __ __ _ __ _ __ __ __ _ __ _ __ __ _ _ 34 

Scaphopods ________________ _________ ____ ----- ___ __ __ _ __ 35 

Dentaliidae _ ___ _ __ _ __ ___ ___ _ _ __ __________ _ _ _ __ _ __ __ 35 

Fossil localities _ _ ______ _ _ __ __ ____ _ _ __ ___ __ _ __ __ __ _ __ ___ __ __ 35 

References cited ------------------------------------------ 36 

Index ------------ ---------------------------------------- 41 

ILLUSTRATIONS 

[Plates follow index] 

1. Crepidula, Semicassis, Neverita, Epitonium, Trochita, Turritella, Natica, Sinum, Polinices, Ficus, Trophosycon. 

2. Bruclarkia, Molopophorus, Priscofusus, Trophonopsis, Crepidula, Cancellaria, Rectiplanes, Trophosycon. 

3. Acila, Nuculana, Archarax, Yoldia, Megasurcula, Ophiodermella, Xenuroturris, Ancistrolepis, Musashia. 

4. Vertipecten, Solamen, Dentalium. 

5. Mytilus, Glycymeris, Lucinoma, Modiolus, Ana.da.ra, Dentalium, Cyclocardia, Clinocardium, Felaniella. 

6. Spisula, Macoma, Conchocele, Clinocardium, Cyclocardia, Solen. 

7. Spisula, Macoma, Tellina. 

8. Macoma, Katherinella, Dosinia. 

9. Securella, Thracia, Panopea. 

Page 

FIGURE 1. Index map showing area of the report ---------------------------------------------------------------------------- 1 

2. (}eneralized geologic map showing distribution of the Clallam Formation and fossil localities ------------------------ 2 

3-7. Photographs showing: 

3. Intertidal zone exposure of Dentalium-bearing concretionary sandstone ----------------- --------------------- 7 

4. Massive fossiliferous sandy siltstone at top of the upper member of the Twin River Formation__________________ 8 

5. Intertidal zone exposure of the Clallam Formation showing intensively bioturbated sandstone ________ __ _____ ___ 9 

6. Conglomerate and conglomeratic sandstone lens in the Clallam Formation ____________ ____ __________ __________ 10 

7. Intertidal zone exposure of basal concretionary sandstone of the Clallam Formation --------- - ---------------- 11 

8. Chart showing stratigraphic position of fossil localities in measured sections ---------------------------------------- 12 

9. Photograph showing chaotic blocks of sandstone in intertidal zone exposure ofthe Clallam Formation ___________ __ _____ 13 

10. Diagram showing correlation of the Clallam Formation with other sequences in the Pacific ~orthwest States and the 

provincial marine chronologies _________________________ _________________ ______________________ ____________ ___ _ 17 

III 
IV 

TABLE 1. 

2. 

3. 

4. 

5. 

6. 

7. 

CONTENTS 

TABLES 

Page 

Mollusks from the Clallam Formation near Slip Point listed by Reagan (1909) with taxonomic revisions by Dall (1922) 

and names recognized in this report ------ ----------- ----------------- ---------------------------------------- 4 

Mollusks from the Clallam Formation, northern Olympic Peninsula, Wash --------------------- ---------------- - - --- 5 

Stratigraphic ranges of species from the Clallam Formation in the Pacific Coast Tertiary ---------------------------- 14 

Specifically identified mollusks from the Clallam Formation that are not known to occur in other formations ____ ___ __ 15 

Mollusks characteristic of the Clallam Formation ---------------------------------- ---------------- ------- --------- 15 

Mollusks from the Clallam Formation suggestive of a provincial early Miocene age ---- ----------------- ------------- 16 

New species of mollusks described here and other species believed to be new but represented by material that is inade- quate for formal description ________ __ _______________ ____ _____ ______ _____ ______ ________________ _________ __ ____ 20 
MOLLUSCAN PALEONTOLOGY OF THE EARLY MIOCENE 

CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

By WARREN 0. ADDICOTT 

ABSTRACT 

The Clallam Formation is a predominantly marine sandstone with 

minor conglomerate and siltstone exposed along the Strait of Juan de 

Fuca in northwestern Washington. Marine mollusks occur throughout the 600- to 800-m-thick formation but are especially abundant in 

the lowest 240m. New molluscan data from the Clallam provide the 

paleontologic base for the Pillarian Stage, a provincial timestratigraphic unit of late early Miocene age. Until this study, the 

Clallam had been assigned to the middle Miocene. The new lower 

Miocene stage , characterized by the restricted stratigraphic range of 

Vertipecten fucanus (Dall) and the restricted and overlapping ranges 

of several other mollusks, can also be recognized in coastal Oregon 

and southwestern Washington. Formations coeval with the Clallam, 

and referable to the Pillarian Stage, include the Nye Mudstone, the 

lower part of the Astoria Formation in the Grays Harbor and 

Astoria-Grays River embayments, and at least part of the Hoh rock 

assemblage. On the basis of molluscan data, the Clallam Formation 

is also correlative with the upper part of the "Vaqueros" Stage of 

California and, presumably, t he uppermost part of the Poul Creek 

Formation in the Gulf of Alaska. These correlations are compatible 

with evidence from benthonic foraminiferal assemblages. 

The molluscan fauna of the Clallam consists of 76 taxa, about 

evenly divided between gastropods and pelecypods. Several species 

are undescribed but only five new species-Semicassis pyshtensis, 

Priscofusus goweri, P. slipensis, Ophiodermella olympicensis, and 

Solamen snavelyi-are represented by material adequate for formal 

description. All the Clallam molluscan assemblages represent inner 

sublittoral depths (less than about 100 m). Qualitative analysis of 

these assemblages indicates a gradual shallowing during deposition 

of the formation. The highest strata in the Clallam contain coal beds 

and are presumably nonmarine. This trend is the concluding phase 

of an Eocene to Miocene depositional cycle in which maximum 

depths, as determined from foraminiferal and lithologic evidence, 

were attained during the Oligocene. 

INTRODUCTION 

The Clallam Formation is a moderately thick, predominantly marine sequence of sandstone, siltstone, 

and conglomerate with a limited onshore distribution 

along the northwestern margin of the Olympic Peninsula, western Washington (fig. 1). The Clallam represents the shallow-water regressive phase of a late 

Eocene to Miocene depositional cycle, the greater part 

of which is represented by the underlying Twin River 

Formation. The Clallam is exposed between Clallam 

Bay and mouth of the Pysht River (fig. 2). Resistant 

sandstone and conglomerate strata within the Clallam 

form a bold 12-km-long segment of coast bordered on 

the west and the east by generally finer grained strata 

of the Twin River Formation. 

Marine mollusks are abundant in the lowest few 

hundred metres of the formation, generally occurring 

as scattered individuals entombed in place. Molluscan 

assemblages also occur near the top of the formation. 

The Clallam may be as thick as 800 m (Gower, 1960). 

This report is a biostratigraphic and systematic 

analysis of molluscan assemblages within the Clallam 

Formation. Biostratigraphic characterization of the 

Clallam Formation and evaluation of the biogeographic significance of the fauna are both dependent 

upon systematic analysis of the fauna. 

48° 

0 

I 

0 

OLYMPIC MOUNTAINS 

OLYMPIC PEN INSULA 

Olympia 

20 40MILES I I I 

I I I I I 

20 40 60 Kl LOMETRES 

FIGURE 1.-Index map of northwestern Washington showing area of 

report (fig. 2). 

1 
2 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

48° 15' 

( Upper 

~ member 

Ttrc, conglom~rat:, .• nd sandstone 

I}?J,j 

Middle member 

Contact, approximately located 

Dotted where concealed 

_..!:!.__ D 

Fault, approximately located 

U, upthrown side; D, downtllrown side 

-+-

Anticline, approximately located 

-+-

Syncline, approximately located 

-ft- Overturned syncline, approximately located 

Measured sectiQll 

x M4414 

Fossil locality 

S',7: 

/?--1/7' 

Op N 

Ju-<~ 

1 

/1( 

<0e14, M4681, NP 163 

Puc-<~ 

NP 162 

160 

Ttru 

0 2 3MILES 

0 2 3 4 5 Kl LOMETRES 

FIGURE 2.- Distribution of the Clallam Formation and fossil localities. Based on mapping by Gower (1960) with minor modifications made 

by Gower and Parke Snavely (written commun., January 1975). 

The biostratigraphy of the Clallam is of especial 

interest because the formation serves as the type section for the Pillarian Stage (Addicott, 1976). It is also 

important in recognition and correlation of the boundary between the provincial lower and middle Miocene. 

The provincial early-middle Miocene boundary has 

been previously placed at the contact between the Clallam and the underlying Twin River Formation by 

Moore (1963), Addicott (1970a) and other molluscan 

specialists. Although there is a well-defined change in 

the megafauna across this boundary, evidence considered in this report suggests reassignment of the Clallam to the provincial early Miocene. Foraminiferal 

specialists, however, have generally placed the provincial Oligocene-Miocene boundary at the base of the 

Clallam Formation. This coastal section is well suited 

as a standard section because fairly diverse, shallowwater molluscan assemblages occur in both the Twin 

River and Clallam Formations. Benthonic foraminifers 

also occur across this boundary, permitting correlation 

with the provincial microfauna! chronology. 

The geographic location of the Clallam Formation is 

especially critical in that it provides a potential 

biogeographic tie between Miocene assemblages of the 

Gulf of Alaska and Alaska Peninsula, far to the northwest, with those of the conterminous United States (lat 

33°-48° N.). The Clallam assemblages define the 

northernmost occurrence of a late early Miocene mol-
PREVIOUS FAUNAL STUDIES 3 

luscan province of relatively warm-water aspect in 

coastal Washington and Oregon. This province is 

characterized by a small, but persistent, element of 

mollusks that are closely related to species living in 

subtropical faunas at much lower latitudes along the 

Pacific coast. 

A modern taxonomic evaluation of the currently 

known molluscan fauna is a necessary prelude to the 

biostratigraphic and biogeographic analyses. Although 

interest in the Clallam mollusks has spanned more 

than 70 years since they were first noted in connection 

with the discovery of coal seams near the top of the 

formation (Arnold, 1905), there has never been a 

thorough taxonomic or biostratigraphic treatment of 

the entire fauna. A generalized systematic study of the 

fauna was made by Reagan (1909) who recognized 25 

mollusks in the Clallam, less than one-third the 

number now known from the formation. 

Paleontologic sampling of the Clallam Formation for 

mollusks and other larger invertebrates during the 

period 1968--7 4 has yielded a fairly diverse fauna of 76 

species of mollusks, about evenly divided between gastropods and pelecypods. Of the 11 taxa that are undescribed, only five are represented by specimens sufficiently well-preserved for formal description. 

ACKNOWLEDGMENTS 

I was aided in my fieldwork by Parke Snavely, Jr., 

Rowland Tabor, Norman MacLeod, Saburo Kanno, 

John Miller, and James Pearl. Howard Gower and 

Parke Snavely provided field maps and aerial photographs in addition to helpful discussions on the 

stratigraphy and geologic structure of the Twin River 

and Clallam Formations. Weldon Rau furnished data 

on foraminiferal assemblages from the Twin River and 

Clallam Formations. A. Myra Keen of Stanford U niversity kindly lent material from the early collections 

made by Harold Hannibal (Arnold and Hannibal, 

1913) for photography and laboratory study. V. Standish Mallory made available collections from the 

Burke Museum, University of Washington, for study. 

Saburo Kanno, Tokyo University of Education, Japan, 

furnished a specimen of Mytilus from Hokkaido for illustration here. The critical comments of Howard 

Gower, Ellen Moore, and Parke Snavely were beneficial. Fossil photography is by Kenji Sakamoto. 

PREVIOUS FAUNAL STUDIES 

Molluscan fossils of the Clallam Formation attracted 

the interest of several geologists during the early 

1900's after the discovery of coal seams near the top of 

the formation (Gilman, 1896; Arnold, 1905). Noteworthy are the reports of Ralph Arnold (1905, 1906, 1909, 

and 1913 [with Harold Hannibal] ), Albert B. Reagan 

(1909), and Charles E. Weaver (1912, 1916a, 1916b). 

These geologists briefly described the stratigraphic sequence of the Clallam Formation and also identified 

molluscan assemblages from the coastal area between 

Clallam Bay and Pillar Point. A few new mollusks 

we:re described from these exposures by Reagan (1909) 

and Weaver (1012). However, paleontologic investigation of the larger marine invertebrates of the Clallam 

has not passed beyond the reconnaissance phase. Virtually no additional work was done on the mollusks or 

their biostratigraphy during the ensuing 60 years. A 

few publications during this period, however, do contain incidental references to Clallam taxa (Tegland, 

1929; Etherington, 1931; Slodkewtisch, 1938; Durham, 

1944; Stirton, 1960; Moore, 1963; Addicott, 1969, 

1970a). While interest in the Clallam mollusks languished, detailed taxonomic studies of the closely related Miocene fauna of the Astoria Formation of Oregon and southwestern Washington (Etherington, 1931; 

Moore, 1963) and the early and middle Miocene faunas 

of the Gulf of Alaska (Kanno, 1971) were completed. 

Although these are useful in working with the Clallam 

mollusks, the fauna of the Clallam contains many taxa 

not previously known from Miocene formations in the 

Pacific Northwest States and Alaska and is sufficiently 

unique to warrant systematic description and analysis. 

Arnold (1906) included marine shale, sandstone, and 

conglomerate lying stratigraphically above the Eocene 

Crescent Formation in his original description of the 

Clallam Formation. Now almost all of this sequence is 

included in the Twin River Formation of Brown and 

Gower (1958). The name Clallam is retained for the 

uppermost part of this middle Tertiary sequence because Arnold designated exposures at the very top of 

his formation, between Clallam Bay and Pillar Point 

(fig. 2), as the type locality. He recognized five faunas 

[faunal assemblages] in his unrestricted Clallam Formation; only two are from the Clallam, as redefined 

here; the other three are from the underlying Twin 

River Formation. The two uppermost localities were 

near Slip Point (fig. 2); 18 mollusks were listed from 

them. 

Reagan (1909) first described and illustrated molluscan fossils from the Clallam. Within the Clallam Formation as defined here, he recognized three. successive 

faunal ((horizons" -actually assemblages-from three 

localities at East Clallam [near Slip Point]. One of 

these was described as intermediate between Arnold's 

(1906) two localities that are from the redefined Clallam Formation. Twenty-seven of Reagan's (1909, p. 

170--173) species were from these three Miocene 

localities in the Clallam. Six of these species, and .~ 

variant of Tellina arctata (Conrad) [ =Macoma arctata 
4 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

TABLE 1.-Mollusksfrom the Clallam Formation nearSlipPointlisted by Reagan (1909, p. 172-173, and 181) with taxonomic revisions by Dall 

(1922) and names recognized in this report 

[A larger list of mollusks from the Clallam Formation <Reagan, 1909, p. 197-198-east Clallam-Neah Bay series! includes many species from strata now mapped as Twin River Formation] 

Reagan (19091 Dall (19221 This report 

Gastropods: Trochita inornata Gabb _______________________ _ Trochita inornata Gabb _____________________ _ ?Calyptraea sp. 

Polynices (Lunatia?) olympidii Reagan, n. sp ___ _ Not determined. 

Polynices (Neverita) saxea Conrad _____________ _ Amauropsis? oregonensis pall -------------- Do. 

Sigaretus scopulosus Conrad _________________ _ Sinum scopulosum Conrad _________________ _ Sinum scopulosum (Conrad). 

Bruclarkia oregonensis (Conrad). 

Pisania clallamensis Reagan, n. sp ___________ _ ?Buccinum clallamensis Reagan _____________ _ 

Pelecypods: Nucula (Acila) castrensis Hinds _______________ _ Nucula (Acila) conradi Meek _______________ _ Acila conradi (Meek). Yoldia impressa Conrad _____________________ _ Yoldia reagani Dall, n. nom ---------------- Y oidia supramontereyensis 

Arnold. 

Petunculus patulus? _________________________ _ 

Pecten (Chlamys) fucanus Dall? _______________ _ 

Pecten (Chlamys) wattsi, var. morani Arnold? __ Pecten (Patinopecten) propatulus Conrad? _____ _ 

Glycymeris sp. 

Vertipecten fucanus (Dall). 

Not determined. 

Phacoides acutilineatus Conrad _______________ _ Phacoides acutilineatus Conrad _____________ _ Vertipecten fucanus (Dall). 

Lucinoma acutilineata (Conrad). Mactragibbsana Meek _______________________ _ 

Tellina arctata Conrad _______________________ _ Spisula albaria Conrad _____________________ _ 

Tellina arctata (Conrad) var.juana Reagan __ Tellina arctata (Conrad) var.juana Reagan __ 

Spisula albaria (Conrad). 

M acoma arctata (Conrad). 

Tellina arctata, var.juana Reagan, n. var _____ _ Do. 

Tellina clallamensis Reagan, n. sp ___________ _ 

Metis alta Conrad ----------------------------

Tellina oregonensis Conrad _________________ _ Tellina emacerata Conrad. 

Not determined. 

Saxidomus gibbosus Gabb ___________________ _ Marcia oregonensis Conrad _________________ _ Katherinella angustifrons 

(Conrad). 

Venus (Chione) clallamensis Reagan, n. sp _____ _ Chione securis Shumard ___________________ _ Securella ensifera (Dall). 

Venus (Chione) olympidea Reagan, n. sp. _____ _ Venus (Chione) angustifrons Conrad ___________ _ Antigona olympidea Reagan ----------------

Cyclinella? sp ------------------------------

Do. 

Katherinella angustifrons 

(Conrad). 

Panopea generosa Gould _____________________ _ 

Teredo sp ------------------------------------

Panope abrupta Conrad _____________________ _ Panopea abrupta (Conrad). 

Teredo sp. indet ---------------------------- Teredo sp. Teredo bulbosus Reagan, n. sp _______________ _ Do. 

Scaphopod: 

Xylotrya? substriata Conrad _______________ _ 

Dentalium substriatum Conrad _______________ _ Dentalium? substriatum Conrad _____________ _ Dentalium pseudonyma 

Pilsbry and Sharp. 

Conrad], were described as new. Dall (1922) 

reexamined the specimens that Reagan (1909, pls. 1-3) 

illustrated and made significant taxonomic revisions. 

These are correlated with names used in this report in 

table 1. 

Subsequent study of other collections from the uppermost part of Arnold's (1906) Clallam Formation 

added a few more taxa to the known fa una; Arnold and 

Hannibal (1913) listed 34 species of mollusks from five 

localities in the Clallam, and Weaver (1916a) listed 43 

species from two localities. Neither of these, nor any of 

the subsequent reports in which Clallam mollusks 

have been listed (Etherington, 1931; Durham, 1944; 

Moore, 1963), dealt specifically with the biostratigraphy of the formation or the molluscan taxonomy. 

Relatively little work has been done on other kinds 

of marine organisms from the Clallam Formation. A 

few benthonic foraminifers have been recorded from 

the Clallam by Rau (1964); these, and stratigraphic 

relations, suggest assignment of the Clallam to the 

Saucesian Stage of Kleinpell (1938). A marine carnivore was described from the Clallam Formation by 

Stirton (1960) who also noted the occurrence of cetacean bones and shark teeth. 

Late Paleogene and Neogene provincial molluscan 

stages for the Pacific Northwest States and western 

Canada were described in two reports published after 

this manuscript was completed (Armentrout, 1975, 

and Addicott, 1976). Unfortunately processing of this 

manuscript had reached a stage where only limited 

referencing of these stages was feasible following final 

editing and completion of the artwork. 

MOLLUSCAN FAUNA 

Collections obtained during this investigation have 

tripled the size of the previously known fauna of the 

Clallam Formation. Among the previously unreported 

mollusks are a few newly described speciesSemicassis pyshtensis, Priscofusus goweri, P. slipensis, 

Ophiodermella olympicensis, and Solamen snavelyi. In 

addition, six other mollusks appear to be undescribed 

but are represented by poorly preserved material inadequate for formal description. In all, 76 molluscan 

taxa are identified from the Clallam (table 2). 

Taxonomically, gastropods and pelecypods are about 

evenly represented in the Clallam Formation: 34 gastropod and 39 pelecypod taxa. In some assemblages, 

however, there may be twice as many species of 

pelecypods as gastropods, and in individual collections 

pelecypods usually far outnumber gastropods in numbers of individual specimens. 
MOLLUSCAN FAUNA 

TABLE 2.-Mollusks from the Clallam Formation, northern Olympic Peninsula, Wash. 

[x, present as identified; cf., simi:l.ar form; aff., comparable but apparently different form;?, doubtful identification] 

Gastropods: Turritella oregonensis (Conrad) (pl. 1, figs. 10, 11, 17) ____ ··- _ _ __ __ __ _ _ _ _ ___ _ __ __ _ _ __ __ _ _ _ _ __ _ _ X 

Epitonium clallamense Durham ·(Pl. 1, figs. 8, 

13) ---- . ----------------------------------- Trochita n. sp. Moore (pl. 1, figs. 9, 12, 18) ____ x 

Crepidula praerupta Conrad (pl. 1, figs. 1, 22; pl. 2, fig. 2·i)__________________________________ X 

Crepidula princeps Conrad (pl. 1, figs. 6, 7) ____ x 

Crepidula rostralis (Conrad) (pl. 2, figs. 23, 

25)---- ------------------------------------ Crepidula sp. (pl. 1, fig. 23) _________________ _ 

Natica cf.!V. clarki Etherington (pl. 1, figs. 19, 27, 

28)---- ------------------------------------ Natica uohesi Addicott (pl. 1, figs. 14-16) 

Neuerita jamesae Moore (pl. 1, figs. 4, 5, 20, 

24) ---------------------------------------- Polinices uictorianus Clark and Arnold (pl. 1, fig. 

25)---- ------------------------------------ Sinum scopulosum <Conrad) (pl. 1, figs. 21, 26)__ x Semicassis pyshtensis n. sp. (pl. 1, figs. 2, 3) ___ _ 

Ficus modesta <Conrad) (pl. 1, figs. 29, 30) ___ _ 

Trophosycon clallamensis (Weaver) (pl. 1, fig. 31; 

pl. 2, fig. 34) ------------------------------ Trophonopsis sp. (pl. 2, fig. 20l _______________ _ 

Ancistrolepis rearensis (Clark) (pl. 3, fig. 26) __ 

Bruclarkia oregonensis (Conrad) (pl. 2, figs. 1-4, 

6, 19) ------------------------------------ Bruclarkia yaquinana <Anderson and Martin) (pl. 2, figs. 5, 7-9)______________________________ x 

Molopophorus n. sp. aff. M. newcombei (Merriam) 

(pl. 2, fig. 16) ------------------------------ Priscofusus aff. P. geniculus (Conrad) (pl. 2, fig. 12)- __ ----- _ _ _ _ ___ _ __ __ _ _ __ __ _ _ _ _ ___ ___ __ __ X 

Prisco{ usus goweri, n. sp. (pl. 2, figs. 14, 17, 18, 21) -------- _ _ _ _ __ _ _ _ _ __ __ __ __ __ __ _ _ __ __ _ _ __ X 

Priscofusus slipensis, n. sp. (pl. 2, fig. 13) _____ _ 

Priscofusus cf. P. stewarti (Tegland) (pl. 2, fig. 15)_ _______ -- ___ ----- _ __ _ _ __ _ __ ___ _ __ __ ____ X 

Musashia indurata (Conrad) (pl. 3, fig. 27) ___ _ 

Cancellaria birchi Addicott (pl. 2, figs. 36, 37) __ 

Cancellaria cf. C. oregonensis Conrad (pl. 2, figs. 

26--28) ------------------------------------ X 

Cancellaria cf. C. siletzensis Hanna (pl. 2, fig. 29) _ _ __ __ _ _ __ ___ _ __ __ ___ _ _ _ _ ___ __ __ _ _ __ ___ _ X 

Cancellaria cf. C. simplex Anderson (pl. 2, figs. 

30, 31) ------------------------------------ X 

Cancellaria wynoocheensis Weaver (pl. 2, figs. 32, 

35, 38) ------------------------------------ X 

Xenuroturris antiselli (Anderson and Martin) (pl. 2, fig. 22, pl. 3, figs. 21, 23) _______________ _ 

Ophiodermella olympicensis, n. sp. (pl. 3, figs. 1S-20, 22-24)______________________________ X 

?Rectiplanes sp. (pl. 2, fig. 33) ________________ x 

Megasurcula cf. M. wynoocheensis (Weaver) (pl. 

3, figs. 16, 17) ----------------------------

Scaphopods: 

Dentalium pseudonyma Pilsbry and Sharp (pl. 4, 

figs. 4, 8) ---------------------------------- x Dentalium schencki Moore (pl. 5, fig. lll ______ x 

Pelecypods: 

X 

X 

X 

X 

X 

X 

cf. cf. 

X X 

X 

X X 

X 

Acila conradi (Meek) (pl. 3, figs. 1-3) __________ x x Nucularw calkinsi (Moore) (pl. 3, figs. 4, 6, 10, 

12-14) ------------------------------------ X 

Nuculana. chehalisensis (Weaver) (pl. 3, fig. 

11)---------------------------------------- Nuculana cf N. elmana Etherington (pl. 3, figs. 

8, 9) -------------------------------------- Yoldia supramontereyensis Arnold (pl. 3, figs. 7, 

15) ____ ------------------------------------ cf. Archarax dalli (Clark) (pl. 3, fig. 5)____________ x 

Anadara devincta (Conrad) (pl. 5, figs. 6, 10) __ 

Anadara aff. A. lakei (Wiedey) (pl. 5, figs. 8, 

9) ---· .. ·---------------------------------- X 

Glycymeris sp. (pl. 5, fig. 3) _________________ _ 

Modiolus n. sp.? afT. M. restorationensis Van Winkle (pl. 5, fig. 5)________________________ x 

Mytilus n. sp. aff. M. tichanovitchi Makiyama (pl. 5, figs. 1, 2, 16, 18) ____________________ x 

Solamen snavelyi, n. sp. (pl. 4, figs. 6, 9) ______ x 

Vertipecten fucanus (Dall) (pl. 4, figs. 1, 2, 5, 7, 

10, 12) ------------------------------------ X X 

Lucinoma acutilineata <Conrad) (pl. 5, figs. 4, 7, 15 l ___ ... _ __ __ __ _ _ __ __ ____ __ _ _ __ __ _ ___ __ _ _ __ cf. x 

Conchocele disjuncta Gabb (pl. 6, fig. 7)________ x 

Felaniella sp. (pl. 5, fig. 17) __ ---------------- Cyclocardia subtenta (Conrad) (pl. 5, fig. 12; pl. 

6, figs. 9, 10) ------------------------------ X X 

Clinocardium n. sp.aff. C. nuttalli(Conrad)Moore 

(pl. 5, Jig.13,pl.6, fig:8) ------------------- X 

Spisula albaria (Conrad) (pl. 6, fig. 3; pl. 7, figs. 

2, 3, 11) ---------------------------------- X X 

Spisula albaria goodspeedi Etherington (pl. 6, 

fig. 14, pl. 7, fig. 1) ------------------------ X X 

Spisula cf. S. hannibali Clark and Arnold (pl. 6, 

fig. 11) ------------------------------------ X 

X 

? 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X X 

X 

X 

X 

X X 

X X X 

X 

X 

X 

X 

X 

X cf. X 

cf. 

X 

X 

X X 

X 

X X X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

x cf.x cf. x 

XX cf. X X X X 

X X 

X 

X X 

cf. x X 

X 

X X 

X 

X X X 

X X X X d X X X X X X X 

X 

X cf X X 

X 

X X X X X X 

X 

X X X X X d X X X X X 

X d d X d X 

X 

5 

X 

X 

X 

X 

X 

X 

X 

X 
MOLLUSCAN PALEONTOLOGY, LOWER MI0<:0ENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

TABLE 2.-Mollusks from the Clallam Formation, northern Olympic Peninsula, Wash.-Continued 

Pelecypods:-Continued 

Spisula sookensis Clark and Arnold (pl. 6, figs. 

1, 16) -------------------------- X 

Spisula sp. (pl. 6, fig. 61 ______________________ x 

Solen conradi Dall (pl. 6, fig. 12) ______________ x x ? 

Tellina emacerata Conrad (pl. 7, figs. 5, 7, 101__ x 

Macoma albaria Conrad (pl. 7, figs. 13--15, 17, 

20) ------------------- _ -------- __ ---------- X X 

Macoma arctata (Conradi (pl. 7, figs. 4, 6, 8, 14, 

18, 221 -----------------------·------------- X X 

Macoma astori Dall (pl. 7, figs. 9, 21) __________ cf. 

Macoma sookensis Clark and Arnold (pl. 7, fig. 23; pl. 8, figs. 1, 2, 5) _________________________ _ 

Macoma n. sp. Moore (pl. 8, fig. 4\ __________ _ 

Macoma n. sp. aff. M. secta (Conrad) (pl. 8, fig. 

6) ---------------------------------------- Macoma cf. M. twinensis Clark (pl. 6, fig. 5)____ x 

Katherinella angustifrons (Conradi (pl. 8, figs. 7, 8, 11-18)________________________________ X X X 

Dosinia whitneyi (Gabbi (pl. 8, figs. 9, 101 ____ _ 

Securella ensifera (Dalll (pl. 9, figs. 1-3, 5, 6, 9, 

10, 13) ------------------------------------ X cf. X 

Panopea abrupta !Conradi (pl. 9, figs. 7, 8, 161 ____ x x Panopea ramonensis (Clarki (pl. 9, fig. 15) ____ x 

Thracia trapezoides (Conradi (pl. 9, figs. 4, 12) ____ x x x 

Thracia cf. T. schencki Tegland (pl. 9, figs. 11, 14) ____ ____ __________ ____ __ ____ __ ___ X 

Cephalopod: Aturia angustata (Conrad) ___________________ _ 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

cf. 

Most of the Clallam genera are monospecific. A few 

genera, however, include several species each: 

Macoma, Spisula, Crepidula, Priscofusus, and Cancellaria. Appreciable taxonomic diversity within these 

genera is not unusual in early and middle Miocene 

molluscan faunas of the middle latitudes (Loel and 

Corey, 1932; Moore, 1963; Addicott, 1970b). 

The generally poor preservation of shell material is 

an important factor in the systematic study of the Clallam molluscan fauna. Only in the silty, very fine to 

fine-grained sandstones of the lowest part of the Clallam Formation (fig. 3) are the aragonitic-shelled 

species preserved with original shell material. The few 

calcitic-shelled mollusks, such as the mytilids and the 

pectinids, are preserved with shell material. They constitute slightly more than 5 percent of the fauna. In 

many localities, however, internal molds of both 

bivalves and gastropods are preserved with fair to very 

good representation of the original surface sculpture. 

Most of the gastropods illustrated here are totally devoid of shell material but nevertheless, exhibit sufficiently detailed sculpture to permit confident specific 

identification. 

BIOSTRATIGRAPHY 

INTRODUCTION 

Molluscan assemblages from the Clallam Formation 

are especially significant in the chronostratigraphic 

classification and correlation of the lower part of the 

Neogene sequence of the Pacific Northwest States. The 

Clallam forms the biostratigraphic base for a recently 

recognized provincial stage of early Miocene age, the 

Pillarian Stage (Addicott, 1976). New biostratigraphic 

X 

X 

X X X X X X X 

X 

X 

X 

X 

X 

X 

X 

X 

;( 

X 

;( 

X 

X X ;( --

X 

X 

X X --

X 

X X X X X 

? 

x -- cf. x X cf. X X 

X X X ? 

X X 

X X X X X 

cf. 

data from the present study permitted recognition and 

definition of this stage and, for the first time, determination of the boundary between it and the underlying 

Juanian Stage, a unit that is coeval with the upper 

parts of the so-called Blakeley Stage (Weaver and 

others, 1944, chart 11) and the Matlockian Stage (Armentrout, 1975). Heretofore, there was a sizeable gap 

in faunal control between the type section of the upper 

part of the ((Blakeley" Stage and the stratigraphically 

higher molluscan assemblages of the Clallam Formation (the type section of the Echinophoria apta zone 

(Durham, 1944) in the upper part of the upper member 

of the Twin River Formation forms the biostratigraphic basis for the upper part of the ((Blakeley" 

Stage). Recent collections from a previously unrecognized fossiliferous interval of a few hundred metres 

thickness at the top of the Twin River Formation 

(USGS lacs. M4676, M4682, M4688, M5881, M5882, 

M6374) show that the boundary between these two 

lower Miocene stages, the J uanian and the Pillarian, is 

at, or very close to, the contact between the Twin River 

and Clallam Formations. 

CLALLAM FORMATION 

The Clallam Formation was described by Arnold 

(1906) who included the entire stratigraphic sequence 

lying above the Eocene Crescent Formation in his unit. 

The name was subsequently abandoned by Arnold and 

Hannibal (1913) who substituted the term Monterey 

Formation for the uppermost 600 m of the postCrescent sequence. Their lignitic sandstone exposed 

near Clallam Bay includes strata later assigned to the 

Clallam Formation (Brown and Gower, 1958; Gower, 

1960). The lower part of Arnold's (1906) Clallam For-
BIOSTRATIGRAPHY 

FIGURE 3.-Intertidal wne exposure of Dentalium-bearing concretionary fine-grained sandstone (USGS loc. M4049) in lower part of the 

Clallam Formation about 3 km west-northwest of Pillar Point. 

mation has a complex nomenclatorial history (Arnold 

and Hannibal, 1913; Weaver, 1937). Current usage 

places the basal sandstone and conglomerate overlying 

the Crescent in the Lyre Formation (Brown and others, 

1956) and the stratigraphically higher sequence of argillaceous rock in the Twin River Formation (Brown 

and Gower, 1958). These units have a combined 

maximum thickness of about 6,300 m. 

The name Clallam is here retained for strata exposed between Slip Point, on the west, and Pillar Point, 

on the east, in keeping with Arnold's (1906) original 

designation of strata at the very top of his formation in 

this area as the type locality. As recognized here conglomerate and sandstone exposed between Last Creek 

and Reed Creek and along the coast from the village of 

Seiku westward about 5 km to the mouth of Hoko 

River are reassigned to the upper member of the Twin 

River Formation. The strata in the latter area were 

included by Weaver (1937, p. 173) in the Clallam Formation. In both areas the strata contain clasts of fossiliferous sandstone from which an assemblage of early 

Miocene mollusks referable to the Echinophoria apta 

zone of Durham (1944) has been collected. Sandstone 

at the top of the conglomerate near the mouth of Pysht 

River (USGS loc's. M4676 and M5881) contains in situ 

mollusks that suggest assignment to the E. apta zone. 

Molluscan assemblages from the uppermost 40 m of 

the Twin River Formation (fig. 4; USGS loc's. M4688, 

M5883, and M6374) differ appreciably from the fauna 

of the Clallam Formation. One species, Turritella 

yaquinana Addicott, suggests correlation with rocks in 

Oregon referable to the E . apta zone. Concurrent 

ranges of several other species point to a provincial 

early Miocene age and inclusion in the E . apta zone 

even though the zonal index species does not occur in 

these assemblages. 

The Clallam is estimated to be as thick as 600-800 m 

(Weaver, 1937; Gower, 1960). It is dominantly marine 

sandstone (fig. 5), but it also contains sandy siltstone 

and, locally, granule to cobble conglomerate (fig. 6). 

Thin coal beds and carbonaceous siltstone exposed in a 

synclinal structure near the top of the formation 

(Gower, 1960) indicate nonmarine deposition. The contact with the underlying sandy siltstone of the Twin 
8 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

FIGURE 4.-Massive, fossiliferous (USGS loc. M4688) sandy siltstone at top of the upper member of the Twin River Formation about 2.5 km 

west-northwest of Pillar Point. Base of 1-m-thick sandstone at right edge of photograph marks the base of the Clallam Formation. 

River Formation is conformable and gradational (fig. 

7). It is well exposed on the west flank of the anticline 

near Pillar Point and, also, on the east flank of the 

anticline near Slip Point. There is no evidence of an 

unconformity between the two formations as reported 

by Weaver (1942, p. 131, 174-175). The top of the Clallam is not exposed. 

Folding, faulting, and penecontemporaneous deformation in some segments of the coastal exposures of 

the Clallam Formation make it difficult to place many 

of the fossiliferous strata in stratigraphic succession 

and also preclude accurate determination ofthe overall 

thickness of the formation. Nevertheless, exposures of 

the lowest 240 m of the formation on the facing flanks 

of the two anticlines between Slip Point and Pillar 

Point (fig. 2) are relatively undisturbed. Stratigraphic 

sections (fig. 8) measured on the facing flanks of these 

two structures indicate that the contact between the 

Twin River Formation and the Clallam tends to be 

gradational. Exposures on the east flank of the anticline west of Pillar Point, however, are bounded by a 

fault (Gower, 1960) and include some giant, house-size 

rotated blocks that preclude determination of the 

stratigraphic position of the fossiliferous strata near 

Pillar Point. The top of the measured section on the 

west flank of this anticline is marked by a zone of severely brecciated sandstone (fig. 3) that marks an 

east-west-trending fault. To the west of this fault there 

are some giant rotated blocks of sandstone (fig. 9) with 

a few fossiliferous strata (USGS locs. M4679 and 

M4680) of undetermined stratigraphic position. Strata 

on the northwest flank of the anticline east of Slip 

Point generally strike in an east-west direction and 

appear to be less disturbed than strata at the east end 

of the outcrop belt. 

Fossiliferous strata on the east flank of the anticline 

near Slip Point (USGS locs. M4414 and M4681) and on 

the west flank of the anticline near Pillar Point (USGS 

locs. M4050, M5879, M4049, M5878, M5885) can be 

arranged stratigraphically with a considerable degree 

of precision (fig. 8). 

Several other assemblages seem to be from this part 

of the Clallam Formation but they cannot be located 

with confidence. Although the contact of the Clallam 
BIOSTRATIGRAPHY 9 

FIGURE 5.-Intertidal zone exposure of the Clallam Formation showing intensively bioturbated fine- to medium-grained marine sandstone overlain by finely laminated sandstone with scattered biogenic structures. Locality is about 220m above the base of the Clallam 

Formation and 3 km west-northwest of Pillar Point. 

with the Twin River is not exposed on the south limb of 

the overturned syncline at Slip Point (fig. 2), the 

stratigraphic position of two localities there (M6029 

and M4677) are estimated to be about 130 and 180m, 

respectively, above the base of the formation. The contact of the Clallam with the Twin River Formation is 

not exposed on the faulted north limb ofthe syncline at 

Slip Point (fig. 2), but localities there (M4051, M4413, 

and M5886) may be in the lowest 100 to 300 m of the 

formation, judging by lithologic similarity to better 

known sections. 

The stratigraphic position of the other fossiliferous 

localities cannot be determined with certainty. One of 

these (M4678), however, seems to be at or near the top 

of the formation judging by its position near the apparent axis of the broad synclinal structure (Weaver, 

1937, pl. 14; Gower, 1960) about midway between Slip 

Point and Pillar Point. 

In view of the structural complications, the Clallam 

assemblages are placed in two broadly defined stratigraphic packages based on geologic mapping by Gower 

(1960). One includes the tectonically undisturbed basal 

240 m of the formation that conformably overlie the 

Twin River Formation; the second includes a single 

locality (M4678) near the top of the formation at an 

undetermined interval above the lower unit, possibly 

as much as 800 m (Gower, 1960). Several localities can 

be confidently placed in stratigraphic sequence in the 

basal part of the Clallam (fig. 8), as previously shown, 

but most cannot. Most, if not all, of these other assemblages, however, are similar to the material from 

the lower part of the Clallam and may well represent 

that part of the formation. 

There is a distinct faunal hiatus between molluscan 

assemblages of the upper member of the Twin River 

Formation and those of the Clallam Formation. Nearly 

two-thirds of the specifically determined mollusks from 

the Clallam (table 3) are not known to occur in the 

Twin River or in coeval early Miocene, or older, faunal 

assemblages. This faunal hiatus is attributed to the 
10 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

FIGURE 6.-Steeply dipping conglomerate and conglomeratic sandstone lens in the Clallam Formation that form a prominent point about 

2.5 km east-southeast of Slip Point. View northwest. 

significantly greater taxonomic diversity of the Clallam fauna, a reflection of the much warmer and shallower water environment. 

Several mollusks are unique to the Clallam Formation (table 4) and, for this reason, are of potential value 

biostratigraphically. Among these are new species described here as well as several taxa represented by 

individual specimens, or by poorly preserved material, 

that differ significantly from known species and that 

probably are new. Another species that occurs in the 

Clallam, and that is restricted in stratigraphic occurrence to coeval strata in Oregon, is V ertipecten fucanus. 

This distinctive giant pectinid, which occurs in more 

collections than any other species, is perhaps the most 

characteristic mollusk in the Clallam. Its restricted 

stratigraphic occurrence in the middle Tertiary sequence of coastal Oregon suggests that it can serve as a 

zonal index for part of the provincial early Miocene. 

The Clallam is best characterized biostratigraphically by the unique co-occurrence of several species 

that are also known from younger or older strata in 

western Washington and western Oregon. Species that 

appear in older stratigraphic units but that do not 

range into strata younger than the Clallam include: 

Archarax dalli (Clark), Spisula hannibali Clark and 

Arnold, S. sookensis Clark and Arnold, Macoma 

twinensis Clark, Thracia schencki Tegland, Priscofusus stewarti (Tegland), and Ancistrolepis rearensis 

(Clark). Many species that have their lowest occurrence in the Clallam also occur in stratigraphically 

younger parts of the Astoria Formation of Oregon and 

southwestern Washington (table 3). Others that have 

their lowest occurrence in the Clallam and that range 

into strata of late Miocene age or higher include: Crepidula princeps Conrad, Spisula albaria goodspeedi 

Etherington, and Macoma astori Dall. Some of the 

species in these groups from the Clallam Formation 

are doubtfully identified. 

Mollusks that are characteristic of the Clallam Formation in terms of frequency of occurrence are given in 

table 5. Most of these have a stratigraphic distribution 

that is limited to the Clallam and to the middle 

Miocene Astoria Formation of Oregon, as indicated in 

the table. One pelecypod, V ertipecten fucanus (Dall), is 
BIOSTRATIGRAPHY 11 

FIGURE 7.-Intertidal zone exposures of basal 14-m-thick fine-grained concretionary sandstone of the Clallam Formation about 

2.5 km west-northwest of Pillar Point. Sandstone at right edge of photograph is 2 m thick. View southwest. 

restricted to the Clallam and to the coeval late early sive phase of an Eocene to Miocene depositional cycle 

Miocene Nye Mudstone as well as other formations of in northwestern Washington. 

this age. Faunal change in the stratigraphically higher asAnalysis of the few assemblages from tectonically semblage from locality M4414, which is believed to be 

undisturbed sections in the lowest 240 m of the Clal- from a somewhat higher stratigraphic position (fig. 8) 

lam Formation indicates certain faunal changes that seems to reflect continued shallowing of the deposimay be of local biostratigraphic significance. Several tional environment. This assemblage is smaller than 

species from the lowest parts of the Clallam do not that from M4050 and M5879, yet more than half of the 

range into stratigraphically higher assemblages. taxa are not represented in the stratigraphically lower 

Collections from the basal 60 m of the Clallam (locs. collections. It is composed principally of inner sublitM4050 and M5879) contain several mollusks restricted toral bivalves that reflect the inferred shallowing of 

to this stratigraphic interval: Archarax dalli (Clark), the depositional environment. Only one species, 

Anadara aff. A . lakei (Wiedey), Modiolus n. sp.? aff. M. Semicassis pyshtensis n. sp., is restricted to this asrestorationensis Van Winkle, Conchocele disjuncta semblage. 

Gabb, and M usashia indurata (Conrad). This collection By far the largest assemblage from the Clallam is 

is from a moderately deep sublittoral assemblage, sig- from a stratigraphic interval about 190-210 m above 

nificantly deeper than stratigraphically higher ones in the base of the formation (locs. M4049 and M5878). 

the Clallam. The absence of these species from higher Several species are restricted to this interval: 

assemblages in the Clallam, together with the appear- Clinocardium n. sp. aff. C. nuttalli (Conrad) Moore, 

ance of many shallow inner sublittoral mollusks, Macoma cf. M. twinensis Clark, Priscofusus aff. P. 

points to a shallowing ofthe depositional environment. geniculus (Conrad), Priscofusus cf. P. stewarti (TegThis change of bathymetric facies reflects the regres- land), Cancellaria cf. C. siletzensis Hanna, C. cf. C. 
12 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

Pillar Point area 

Fault 

-M6373 

· ' '· . }M4049, M5878 . . 

: · ... .. . . . . . . . . 

·· . . . ·:. 

. . .. 

· .. ··· ·. 

Clallam Formation 

Upper member of the 

Twin River Formation 

EXPLANATION 

j:·_.·::-. ·.·.:J Sandstone 

~·: ~ .. ·.'j Concretionary . c;::>. ·.c;:::>·. sandstone 

I~.:.'~~·~ Silty sandstone 

t-

~ 

.. ·----j Sandy siltstone 

and mudstone 

Slip Point area 

-+?- (M4677) } South 

flank of 

syncline 

at Slip 

-+?- (M6029) Point 

} M6374 

100 METRES 

50 

0 

FIGURE B.-Stratigraphic position offossillocalities in measured sections of the Twin River and Clallam Formation near Pillar Point 

and Slip Point. 

simplex Anderson, and C. wynoocheensis Weaver. The 

presence of so many seemingly restricted species is directly related to the unusually large number of species 

in the assemblage. It probably also reflects the commingling of mollusks from different communities, inasmuch as this assemblage is from layered shell accumulations possibly brought together by storm waves 

where as those from almost all of the other localities in 

the Clallam consist of widely scattered mollusks deposited in place. 

Differences between these collections from the lowest 200 m-those from the basal 60 m and those from 

190 to 210 m-of the Clallam may prove useful in 

characterization and recognition of units within the 

lower part of the formation. However, because they 

seem to be influenced, to a large degree, by progressive 

shallowing and, perhaps, warming of the depositional 

environment, regional chronologie significance cannot 

be attached to them. 

The small assemblage from what is believed to be 

the upper part of the Clallam Formation (loc. M4678), 

about midway between Pillar Point and Slip Point, has 

only three species that do not occur in collections from 

the lower part of the formation. One is a poorly known 

tellinid, Macoma n. sp. aff. M . secta (Conrad). Another, 

a split-ribbed form of Anadara devincta (Conrad), 

which occurs elsewhere in strata assigned to the Pillarian Stage is not, therefore, indicative of a significantly younger age than assemblages from the lower 

part of the Clallam. The third species, Nuculana chehalisensis (Weaver), is known from middle Miocene 

strata in Oregon and California. 

This highest collection from the Clallam is not considered to represent a distinct biostratigraphic unit, as 

there is a very close similarity, if not identity, with 

assemblages from the lower part of the formation. Accordingly, all the faunal assemblages from the Clallam 

are here regarded as representing a single biostratigraphic unit, of late early Miocene provincial age, correlative with the upper part of the "Vaqueros" Stage of 

California. 

PROVINCIAL CHRONOSTRATIGRAPHY 

AGE AND CORRELATION 

Molluscan specialists have generally assigned the 

Clallam Formation to the provincial middle Miocene . 

There is a very strong resemblance between the Clallam molluscan assemblages and the well-known middle Miocene molluscan fauna of the Astoria Formation 

of Oregon, a fact long evident to stratigraphers (Arnold, 1906; Arnold and Hannibal, 1913; Etherington, 

1931). Many species in the Clallam also occur in the 

fauna of the "Temblor" Stage of central California, the 

standard for the provincial middle Miocene, therefore 

some specialists considered the Clallam to be coeval 

with the "Temblor" Stage (Arnold and Hannibal, 1913; 

Etherington, 1931; Durham, 1944; Addicott, 1969). 

Until now, however, data on the Clallam fauna were so 

few that correlation with the California sequence was 

doubtful (Addicott, 1970a, p. 36). 

The stratigraphic occurrence of several of the mollusks now known from the Clallam (table 6) suggests 

that the formation is of provincial early Miocene age. 

These assemblages indicate correlation with the upper 

part of the "Vaqueros" Stage of the California Coast 

Ranges. This relation is implicit in the foraminiferal 

correlations between the Clallam Formation and 

California Coast Range sections based on benthonic 

assemblages (Kleinpell, 1938; Rau, 1964). Still, most, 

if not all, of the previous age assignments of the Clallam by moll usc an specialists (Etherington, 1931; 

Durham, 1944; Moore, 1963; Addicott, 1967, 1969, 

1970b) have been middle Miocene, or have implied a 
PROVINCIAL CHRONOSTRATIGRAPHY 13 

FIGURE 9.- Chaotic blocks of sandstone in intertidal zone exposure of 

the Clallam Formation about 1 km west of triangulation station at 

Pillar Point. Concretionary bed extending from lower left toward 

upper right defines a west-northwest dipping block underlain by a 

provincial middle Miocene age by correlation of this 

fauna with the Barker's Ranch fauna of the Temblor 

Formation (Addicott, 1970a) of the San Joaquin basin, 

California. And these age assignments have not dealt 

directly with the disparity in correlation based on 

foraminifers. 

The evidence suggesting revision of the provincial 

age of the Clallam is primarily from molluscan data. 

Species given in table 6 suggest, in their totality, a 

provincial early Miocene age. Because of doubtful 

identifications of some species and limited stratigraphic range data for others, practically all of these 

mollusks cannot here be considered as index species at 

this time. 

Spisula sookensis, an early Miocene species from 

southwestern British Columbia, is not known to occur 

in strata of middle Miocene age in the Pacific Northwest. Similarly, the Oligocene and early Miocene 

species Archarax dalli suggests a pre-middle Miocene 

age. The doubtfully identified species, S. hannibali, 

Thracia schencki, and Macoma twinensis are known 

north-northeast dipping block in the lower right indicated by concretionary lenses striking toward lower right hand corner of photograph. View north. 

only from the late Oligocene and early Miocene 

"Blakeley" or Matlockian Stage of this region. 

Two other hi valves are more diagnostic of provincial 

age and correlation. Mytilus n. sp. aff. M. tichanouitchi 

is known elsewhere in the eastern North Pacific only 

from the early Miocene "Vaqueros" Stage of California 

(Allison and Addicott, 1976). This rugose species has 

sometimes been confused with the middle Miocene 

index M. middendorffi (Allison and Addicott, 1976), a 

species that may be its progeny. The more commonly 

occurring and more widespread pectinid, V ertipecten 

fucanus, provides the strongest evidence of an early 

Miocene age in terms of the mega-invertebrate sequence. According to J. T. Smith (oral commun., September 1974: UCMP loc. B1660), this species occurs in 

the lower Miocene Jewett Sand of the San Joaquin basin, California, a unit that also carries lower Saucesian 

benthonic foraminifers. In the Newport Embayment of 

the northwestern Oregon coast, V. fucanus appears in 

the early Miocene (Addicott, 1974) and occurs stratigraphically below Patinopecten propatulus, a wide-
14 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

TABLE 3.-Stratigraphic ranges of species f'rom the Clallam Formation in the Pacific Coast Tertiary 

[Ranges indicated by a dotted line (. .. ) are of species not known to occur in other formations. No attempt is made to show relative stratigraphic occurrence within the Clallam. Ranges 

shown for doubtfully identified mollusks (i.e. , Natica cf. N. clarki) indicate the known stratigraphic occurrence of the unequivocably identified species. Pacific Northwest stages 

are from Armentrout (1 975) and Addicott (1976)) 

Series -------------------- - --------------

CalifOrnia molluscan stage ---------- ---------------

Pacific Northwest mollusca n stage 

Formation __ 

Pelecypods: 

Acila conradi (Meek) -------------------------------- Nuculana calkinsi (Moore) -------------------------- Nuculana chehalisensis (Weaver) ---- -------------- --

Nuculana elmana Etherington ---------------------- Yoldia supramontereyensis Arnold ______ ______ _____ _ 

Miocene 

Oligocene 

Lower 

Unnamed "Vaqueros" 

"Blakeley" 

Pillarian 

Matlockian Juan ian 

Twin Ri ver Formation , 

upper member Clallam ""' Formatio~ 

Middle 

"Temblor" 

Newportian 

Astoria 

Formation 

Upper 

"Margaritan" 

Wishkahan 

Montesano 

Formation of 

Weaver (1912) 

Archarax dalli (Clark) --------------------------- --- f---------l------+-------1 

Anadara devincta (Clark) ---- - ---------------------- f---------1------+-------1 

Anadara aff. A. lakei (Wiedey) ---------------------- Modiolus n. sp.? aff. M. restorationensis Van Winkle __ Mytilus n. sp. aff. M. tichanovitchi Makiyama __ ____ _ _ 

So/amen snavelyi, n. sp. ----------------------------

Vertipecten fucanus (Dall) --------------------------

Lucinoma acutilineata (Conrad) ---------------------- Jc.------+--------1------1--------1 

Conchocele disjuncta Gabb --- ----------------------- f---------1------+------1------+-----~ 

Felaniella parilis (Conrad) -------------------------- ~o~t...o~----+-----+------+------+-----­ Cyclocardia subtenta (Conrad) ---------------- ------ Clinocardium n. sp. aff. C. nuttalli (Conrad) Moore ___ _ 

Spisula albaria (Conrad) ---------------------------- f---------1------+------1------+---- ~ Spisula albaria goodspeedi Etherington __ _______ ____ _ 

Spisula cf. S. hannibali Clark and Arnold _____ __ ____ _ 

Spisula sookensis Clark and Arnold ------------------ Solen conradi Dall ----------------------------------

Tellina emacerata Conrad -------------------------- f.--------+------+------+------+------ Macoma albaria Conrad - ---------------------------

Macoma arctata (Conrad)---------------------------- IE------+-------1---- --t-------i 

Macoma astori Dall -------------------------------- Macoma sookensis Clark and Arnold ----------------

Macoma n. sp.? Moore ------------------------------ Macoma n. sp. aff. M. secta (Conrad) ------------ ----

Macoma cf. M. twinensis Clark ---------------------- f--------+------j-------j 

Katherinella angustif'rons (Conrad) ------------------

Dosinia whitneyi (Gabb) ---------------------------- f---------1------+-----+--------1 

Securella ensifera (Dall) ----------------------------

.. 

Panopeaabrupta (Conrad) -------------------------- ~-----+--------1---- -1--------+------~~ Panopea ramonensis (Clark) ------------------------ ~o~"'~-----+------+---- --1 

Thracia trapezoides (Conrad) ------------------------ f-------f--------1-------/---- ~ 

Thracia cf. T. schencki Tegland ---------------------- f--------+------+---------1 

Cephalopod: 

Aturia angustata (Conrad)?------------------------- - IE------+------+------t-------i 

Gastropods: 

Turritella oregonensis (Conrad) ----------------------

Epitonium clallamense Durham---------------------- Trochita n. sp. Moore _______ _________ _______ ________ _ 

Crepidula praerupta Conrad ------------------------ Crepidula princeps Conrad ------------- ------------- Crepidula rostra/is (Conrad) ------------------------ Natica cf. N. clarki Etherington ______ ___ ___ __ _______ _ 

Natica vokesi Addicott --------------------------- - -- Neverita jamesae Moore _______ _ ------------------ __ Polinices victorianus Clark and Arnold ______ ____ ___ _ 

Sinum scopulosum (Conrad) - -------------------- --- f-------+-- --1------t------+-----;,~ Semicassis pyshtensis, n. sp. - - - --------------------- Ficus modesta (Conrad) ____ __ ___ _____ ___ ____ __ ______ _ ~-----+------+------1--------i 

Trophosycon clallamensis (Weaver) -------- ---------- ~ 

Ancistrolepis rearensis (Clark) ---------------------- f---------+------J- ---- ----1 

Bruclarkia oregonensis (Conrad) -------------------- f----------1--------i 

Bruclarkia yaquinana (Anderson and Martin) _______ _ 

Molopophorus n. sp. aff. M. newcombei (Merriam) ___ _ 
PROVINCIAL CHRONOSTRATIGRAPHY 15 

TABLE 3.-Stratigraphic ranges of species from the Clallam Formation in the Pacific Coast Tertiary-Continued 

Miocene 

Series Oligocene 

Lower Middle Upper 

California molluscan stage __________________ _ Unnamed "Vaqueros" "Temblor" "Margaritan" 

"Blakeley" 

Pillarian Newportian Wishkahan 

Pacific Northwest molluscan stage Matlockian Juanian 

Formation ______ _ 

Gastropods:-Continued 

Priscofusus aff. P. geniculus (Conrad) Moore _________ _ 

Priscofusus goweri, n. sp. ----------------------------

Twin River Formation, 

upper member Clallam """' Formation """' 

Astoria 

Formation 

Montesano 

Formation of 

Weaver (1912) 

Priscofusus cf. P. stewarti (Tegland) __________________ -------+------+---------! 

Priscofusus slipensis, n. sp. _________________________ _ Musashia indurata (Conrad) _______________________ _ 

Cancellaria birchi Addicott _________________________ _ 

Cancellaria cf. C. oregonensis Conrad _______________ _ 

Cancellaria cf. C. siletzensis Hanna _________________ _ Cancellaria cf. C. simplex Anderson _________________ _ Cancellaria wynoocheensis Weaver _________________ _ 

Xenuroturris antiselli (Anderson and Martin) _______ _ Ophiodermella olympicensis, n. sp. _________________ _ 

Megasurcula cf. M. wynoocheensis (Weaver) _________ _ 

Scaphopods: 

Dentalium pseudonyma Pilsbry and Sharp ___________ _ Dentalium schencki Moore _________________________ _ 

spread species restricted to the provincial middle 

Miocene. Data presented by Moore (1963, table 2) show 

that these two taxa have virtually exclusive stratigraphic distributions in the Newport Embayment. Occurrences of V. fucanus are in strata mapped as Nye 

Mudstone (Snavely and others, 1969; 1976) whereas 

those of Patinopecten are in the stratigraphically 

higher Astoria Formation. At or near the Nye-Astoria 

contact, however, Moore (1963, table 2, loc. 181) does 

report the two taxa from the same locality. This cooccurrence is believed to be the transitional overlap 

between the two species. The co-occurrence of these 

genera in an old collection from Astoria, Oreg. (Moore, 

1963, table 2, loc. 1a), may represent the same situation. It is also possible that this collection includes 

material from a substantial stratigraphic intervalboth the early and middle parts of the section thereTABLE 4.-Specifically identified mollusks from the Clallam Formation that are not known to occur in other formations 

Gastropods: 

Semicassis pyshtensis, n. sp. 

Trophosycon clallamensis (Weaver) 

Molopophorus n. sp. aff. M. newcombei (Merriam) 

Priscofusus goweri, n. sp. 

Pelecypods: 

Anadara aff. A. lakei (Wiedey) 

Modiolus n. sp.? aff. M. restorationensis Van Winkle 

Macoma n. sp. aff. M. secta (Conrad) 

as the older collections from the Pacific coast commonly do. 

The uniquely orbicular species Macoma n. sp. Moore 

(1963) also occurs in the Nye Mudstone and the Clallam Formation. This distribution complements the 

provincial early Miocene distributions of Mytilus n. sp. 

and Vertipecten fucanus. 

Three gastropods are especially suggestive of provincial early Miocene age. Ancistrolepis rearensis has 

TABLE 5.-Mollusks characteristic of the Clallam Formation (species 

that are identified, without doubt, from at least six collections) 

[Species marked with an asterisk(*) also occur in the provincial middle Miocene fauna of 

the Astoria Formation and, so far as is known, are restricted to the lower Miocene Pillar· 

ian Stage and middle Miocene Newportian Stage] 

Gastropods: 

*Trochita n. sp. 

*Bruclarkia yaquinana (Anderson and Martin) 

*Ophiodermella olympicensis, n. sp. 

Pelecypods: 

*Nuculana calkinsi (Moore) 

V ertipecten fucanus (Dall) 

*Cyclocardia subtenta (Conrad) 

Spisula albaria (Conrad) 

Tellina emacerata Conrad 

*Macoma albaria Conrad 

*Katherinella angustifrons (Conrad) 

*Securella ensifera (Dall) 

Thracia trapezoides (Conrad) 

Scaphopod: 

*Dentalium schencki Moore 
16 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

been previously recorded only from the late Oligocene 

and early Miocene ((Blakeley" Stage [ =Matlockian 

Stage of Armentrout, 1975]. Priscofusus aff. P. 

geniculus (Conrad) Moore is restricted to exposures of 

the Nye Mudstone in coastal Oregon (as mapped by 

Snavely and others, 1976) and is bracketed, stratigraphically, by occurrences of Vertipecten fucanus 

(Dall) (Moore, 1963, table 2). Its occurrence stratigraphically below the Patinopecten propatulus assemblages of the middle Miocene Astoria Formation is 

likewise suggestive of provincial early Miocene age. 

Molopophorus n. sp. aff. M. newcombei seems to form a 

phylogenetic link between the early middle Miocene 

M. matthewi Etherington and the early Miocene 

species M. newcombei. It is suggestive, therefore, of a 

provincial late early Miocene age. Another gastropod 

that is doubtfully identified because of poor preservation, Priscofusus cf. P. stewarti, may be identical to a 

species known only from the provincial early Miocene 

of the Pacific Northwest. 

Long-range correlation with central and southern 

California based on benthonic foraminifers (Rau, 1964) 

substantiates a late early Miocene provincial age for 

the basal part of the Clallam Formation in terms of the 

California sequence. The boundary between the 

Zemorrian and Saucesian stages is at, or very close to, 

the contact between the Twin River Formation and the 

overlying Clallam Formation (Rau, 1964); the basal 

part of the Clallam is presumably of early Saucesian 

age inasmuch as there is no indication of a depositional 

hiatus between the two formations (fig. 3 and Gower, 

1960). This microfauna! boundary, as discussed by Addicott (1973, 197 4), falls within the lower Miocene 

((Vaqueros" Stage of the California provincial megainvertebrate chronology; in California the lower part of 

the Saucesian Stage is equivalent to the upper part of 

the ((Vaqueros" Stage. The ((Vaqueros" Stage is based 

on tropical and subtropical species restricted to 

California and more southerly latitudes during the 

early Miocene. In the Pacific Northwest, the early 

Miocene is represented by the cooler water molluscan 

assemblages of the Juanian Stage [=upper part of the 

((Blakeley" or Matlockian Stage] and the overlying 

fauna of the Pillarian Stage, represented by the Clallam Formation and the Nye Mudstone. 

Although the discrepancy between mollusks and 

foraminifers in provincial age classification of the Clallam Formation-early Miocene versus middle 

Miocene-has long been apparent, it seems to have 

been disregarded, perhaps because of the reported unconformity at the base of the Clallam and the alleged 

erosion of more than 600 m of the upper member of the 

Twin River Formation (Weaver, 1937, p. 175; Weaver 

and others, 1944). This supposed unconformity has 

been regarded, at least by some specialists (Weaver 

and others, 1944), as representing the missing early 

Miocene ((Vaqueros" Stage. It is shown by Durham 

(1944, fig. 7) as a faunal hiatus between the two formations. In actuality, data considered here show that assemblages from the basal part of the Clallam are 

coeval with the fauna of the early Miocene ((Vaqueros" 

Stage of California as are those from the uppermost 

part of the Twin River Formation (Addicott, 1967). 

These assemblages are not, as previously maintained 

(Durham, 1944; Addicott, 1969), coeval with the middle Miocene fauna of the ((Temblor" Stage. There is, 

therefore, no faunal disconformity or hiatus between 

the two formations as is clearly implied by the conformable and gradational lithologic contact first reported by Gower (1960). 

Correlation of the Clallam Formation with other key 

sequences on the Pacific coast is shown in figure 10. Of 

note is the evidence for assignment of the Astoria Formation of the Newport Embayment, Oreg., to the provincial middle Miocene. Howe (1926), Moore (1963), 

and Addicott (in Snavely and others, 1964) have correlated the Astoria molluscan fauna with the middle 

Miocene ((Temblor" Stage of California. Foraminiferal 

studies support this correlation. Rau (in Snavely and 

others, 1964) has shown that benthonic foraminifers 

from the Astoria Formation and the Nye Mudstone 

which unconformably underlies the Astoria Formation 

in the Newport Embayment are of Sauces ian age. The 

Astoria can be referred to the upper part of the Saucesian Stage on the basis of the reported occurrence of 

upper Saucesian foraminifers in the upper part of the 

underlying Nye Mudstone by Heacock and Boyd 

(1954). According to Rau (in Snavely and others, 1964) 

it may also contain assemblages of Relizian age. Presumably most of the Nye Mudstone, including the 

localities from which distinctive pre-middle Miocene 

assemblages containing Vertipecten fucanus have been 

TABLE 6.-Mollusks from the Clallam Formation suggestive of a provincial early Miocene age 

Pelecypods: 

Archarax dalli (Clark) 

Macoma cf. M. twinensis Clark 

Macoma n. sp. Moore 

Mytilus n. sp. aff. M. tichanovitchi Makiyama 

Spisula sookensis Clark and Arnold 

Spisula cf. S. hannibali Clark and Arnold 

T hracia cf. T. schencki Tegland 

V ertipecten fucanus (Dall) 

Gastropods: 

Ancistrolepis rearensis (Clark) 

Epitonium clallamense Durham 

M olopophorus n. sp. aff. M. newcombei (Merriam) 

Priscofusus aff. P. geniculus (Conrad) Moore 

Priscofusus cf. P. stewarti (Tegland) 
PROVINCIAL CHRONOSTRATIGRAPHY 17 

Benthonic California Pacific Northwest Northern Southwestern Newport Embayment, Gulf of Alaska 

Provincial foraminiferal molluscan molluscan Olympic Mountains Washington Oregon Yakataga District 

series stage stage stage Washington (Wolfe and McKee, 1972; (Snavely and others, (Kanno, 1971; Miller, 

(Kieinpell, 1938) (Weaver and others, (Addicott, 1976) (This report) Rau, 1967) 1969a, 1974) 1971) 1944; Addicott, 1972) 

luisian(?) and 

Middle r- -?-R_!lg!!l!_ __ Astoria Yakataga 

Miocene ''Temblor" Newportian Formation Formation 

Saucesian Astoria 

Formation 

Pillarian Clallam Nye 

Formation Mudstone 

lower 

Miocene "Vaqueros" Upper part of 

Yaquina Paul-Creek 

Juanian Formation Formation 

Upper member of Upper part of 

Zemorrian Twin River lincoln Creek 

Formation Formation 

Upper Unnamed Matlockian or Upper part of 

Oligocene "Blakeley" Alsea Formation 

FIGURE 10.-Correlation of the Clallam Formation with other sequences in the Pacific Northwest States and the provincial marine 

chronologies. 

collected, are of early Saucesian age. Elsewhere in 

Oregon and in southwestern Washington (fig. 10) the 

lower part of the Astoria Formation is of provincial 

early Miocene age. 

The fauna of the Clallam Formation may be coeval 

with molluscan assemblages from the upper part of the 

Poul Creek Formation at the head of the Gulf of 

Alaska. The percentage of species in common with the 

Poul Creek is small (Kanno, 1971, table 4), perhaps 

because of the much cooler water aspect of the Alaskan 

early Miocene fauna. Collections from the uppermost 

200m of the Poul Creek Formation in a measured section at Cape Yakataga (Kanno, 1971) contain meager 

assemblages with few stratigraphically distinctive 

species. One of these, however, Ancistrolepis rearensis 

(Clark), is restricted to the lower Miocene of northwestern Washington. Two mollusks that are restricted 

to the Pillarian Stage represented by the Clallam 

Formation and its molluscan fauna do occur in the 

upper part of the Poul Creek, but their stratigraphic 

position within that interval is not known. These 

species are Vertipecten fucanus [V. sp. Kanno (1971)] 

and Epitonium clallamense Durham. Mollusks that do 

not range into post-early Miocene strata in Oregon and 

Washington and correlative strata in California, 

Aturia, Musashia weaveri (Tegland), Thracia schencki 

Tegland, and Acila gettysburgensis (Reagan), also 

occur in the upper part of the Poul Creek Formation 

(Kanno, 1971; MacNeil, in Miller, 1971). Elsewhere in 

the lower and upper parts of the Poul Creek, Liracassis 

apta (Tegland), a species restricted to the Juanian 

Stage-the lower part of the lower Miocene of Oregon 

and Washington, has been recorded from several 

localities (see Kanno, 1971). 

Close to two-thirds of the mollusks from the Clallam 

also occur in the middle Miocene part of the Astoria 

Formation-the N ewportian Stage-or are represented by closely allied, possibly conspecific, taxa 

(table 3). Several Clallam species, however, are restricted to formations of provincial early Miocene age 

in addition to many others whose concurrent stratigraphic ranges, or position in an inferred evolutionary 

sequence, are indicative of a pre-middle Miocene age. 

The strong similarity between the late early Miocene 

(Pillarian) fauna of the Clallam and the younger middle Miocene (Newportian) fauna of the Astoria Formation is not unique among middle latitude early and 

middle Miocene faunas of the eastern North Pacific. 

The faunas of the lower Miocene ~~vaqueros" and the 

middle Miocene ~~Temblor" Stages of California also 

have many species in common. Consequently, differentiation between these California stages is difficult. 

In comparison with middle Miocene faunas, the early 

Miocene faunas of both the ~~vaqueros" and the Clallam Formation are characterized by a much lower level 

of taxonomic diversity. This relation further complicates recognition and differentiation of provincial 

early Miocene faunal assemblages. 

In summary, reevaluation of the provincial age of 

the Clallam Formation, based principally on new 
18 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

faunal data and further analysis of the stratigraphic 

ranges of key species in other Pacific coast sequences, 

suggests that the molluscan assemblages of the Clallam Formation are of early Miocene rather than middle Miocene provincial age. They represent the later 

part of the provincial early Miocene and are readily 

separable from the fauna of the Juanian Stage and the 

coordinate upper parts of the ((Blakeley" and Matlockian Stages [Echinophoria apta Zone of Durham (1944)]. 

They form the faunal basis for the recently named Pillarian Stage (Addicott, 1976). Benthonic foraminiferal 

correlations with the provincial microfauna! standard 

sections in California (Kleinpell, 1938; Rau, 1964) 

support this reassignment. 

PILLARIAN STAGE 

The Clallam Formation has been designated the 

type section for the Pillarian Stage (Addicott, 1976). 

This stage, which represents the upper part of the 

lower Miocene of Oregon and Washington (fig. 10), is 

represented by the fauna of the Nye Mudstone of the 

Newport Embayment, the lower part of the Astoria 

Formation in the type area near Astoria, Oreg., and in 

the Grays River quadrangle and possibly other areas 

in southwestern Washington, and the Hoh rock assemblage (Rau, 1973) of the western margin of the 

Olympic Mountains, Wash. The Pillarian is equivalent 

to the upper part of the so-c?-lled Vaqueros Stage (see 

Addicott, 1972) of the California Coast Ranges. 

PALEOECOLOGY 

BATHYMETRY 

All the molluscan assemblages from the Clallam 

Formation represent inner sublittoral depths (less 

than 100m). Qualitative analysis of assemblages from 

the tectonically undisturbed sections in the lower part 

of the Clallam Formation (fig. 8) points to a gradual 

shallowing of the depositional environment. This trend 

is an extension of the sh;1llowing of depositional environments in the upper part of the Twin River Formation indicated by benthonic foraminiferal assemblages 

(Rau, 1964). This shoaling is the concluding phase of 

an Eocene to Miocene depositional cycle in which 

maximum deepening took place during the Oligocene. 

Elsewhere in western Washington the concluding 

phase of the transgressive-regressive cycle is represented by the middle Miocene part of the Astoria 

Formation (Rau, 1967, p. 25; Wagner, 1967). 

The stratigraphically lowest assemblage from the 

Clallam (loc. M6375) consists of a few taxa suggestive 

of deposition in the middle part of the sublittoral zone. 

Most of these species also occur in the much larger, and 

more environmentally definitive, collections from a 

7-m interval nearly 60 m above the base ofthe Clallam 

(locs. M4050 and M5879). Modern depth ranges of genera and species composing this assemblage suggest deposition in the middle to lower parts of the inner sublittoral zone-possibly 50-7 5 m. Species composing 

this assemblage occur as isolated individuals, presumably in place. The bivalves are articulated. The assemblage is moderately large for the Clallam-25 

species-but considerably smaller than a stratigraphically higher assemblage of current or storm wave deposited mollusks that occurs about 130m stratigraphically higher in the section (loc. M4049). 

The basal assemblage from the Clallam contains a 

few living species of moderately deep inner sublittoral 

aspect: Conchocele disjuncta Gabb, Panopea abrupta 

(Conrad), and Thracia trapezoides (Conrad). Available 

data on the depth ranges of these species in the modern 

eastern North Pacific indicate an overlap in the interval between 18 and 75 m (Kanno, 1970; unpub. data 

from Rae Baxter [Thracia] and Lynn Glover 

[Panopea]). Other mollusks characteristic of moderate 

depths in the sublittoral zone, but that extend downward well into the bathyal zone, include Archarax, 

Lucinoma, Solamen, and Musashia. Collectively, these 

mollusks suggest that water depths were in the lower 

part of the interval indicated by living speciesprobably no shallower than 50-75 m. Archarax lives at 

depths greater than about 110m off the eastern North 

Pacific coast today. M usashia is locally extinct but is 

represented by species that live at depths of 100m or 

greater off the coast of Japan (Habe, 1964). The other 

genera are suggestive of somewhat shallower water 

conditions in terms of their known depth ranges. Solamen ranges from about 30 m into the upper bathyal 

zone (Soot-Ryen, 1955) along the Pacific coast, and 

Lucinoma annulata (Reeve), a homologue of the 

Oligocene and Miocene species L. acutilineata, ranges 

from about 15m (Smith and Gordon, 1948) to bathyal 

depths (Parker, 1963) in the eastern North Pacific. 

The outer sublittoral environment suggested by 

modern bathymetric data for Musashia and Archarax 

seems anomalously deep for this assemblage in that 

many of the other mollusks are of inner sublittoral 

aspect. For this reason, it is inferred that during the 

early Miocene these two genera were living at somewhat shallower depths than they are now found and 

that they were not restricted, as indicated by their 

modern bathymetric occurrences, to the outer part of 

the sublittoral zone or greater depths. 

A somewhat higher assemblage from the east flank 

of the anticline near Slip Point (loc. M4414) records 

shallowing to depths in the middle to upper part of the 

inner sublittoral zone. Most of the species in it also 

occur in the collections from the lowest 55 m of the 
PALEOECOLOGY 19 

Clallam, but there are none of the deeper water indicators. Among the mollusks not found in stratigraphically lower collections, Mytilus n. sp. aff. M. 

tichanovitchi Makiyama is probably the most significant bathymetric index. Mytilus is characteristic of 

shallow inner sublittoral to intertidal depths along the 

eastern North Pacific coast today. It is of fairly common occurrence in this and other localities in the lower 

300m of the Clallam, but does not occur in the lowest 

55 m of the formation. The appearance of Dosinia is 

also suggestive of shallower water conditions as well as 

probable increase in marine water temperature in 

terms of its modern distribution in the eastern North 

Pacific (Keen, 1971). 

By far the largest assemblage (locs. M4049 and 

M5878) in the lower part of the Clallam Formation is 

from intertidal zone exposures on the west flank of the 

anticline near Pillar Point about 190-210 m above the 

base of the formation (fig. 8). Fossils in this assemblage 

occur as layered concentrations whereas stratigraphically lower fossils occur as isolated individuals, apparently in place. The larger size of the assemblage from 

localities M4049 and M5878 may well be due to the 

mode of formation as current or storm wave concentrations; the assemblage may include specimens from 

more than one community. 

The size of the assemblage from localities M4049 and 

M5878 permits qualitative comparison with the moderately large assemblage from near the base of the 

Clallam (loc. M4050). It is interesting to note that none 

of the deeper sublittoral genera and species from the 

lowest assemblage (M4050) reappear in this one, particularly in view of the fact that this assemblage may 

include representatives from more than one biotope. 

There are several mollusks that do not occur in stratigraphically lower collections. And these are suggestive 

of inner sublittoral depths appreciably shallower than 

near the base of the Clallam-possibly from about 15 

to 35 m. Shallow inner sublittoral depths are suggested 

by the occurrence ofClinocardium n. sp. aff. C. nuttalli, 

Y oldia supramontereyensis, and the abundance and 

diversity of mactrids comparable to species living at 

depths of less than 35 m along the Pacific coast (Smith 

and Gordon, 1948; Quayle, 1973). An upper limit of 

about 15 to 20m for the large assemblage from M4049 

and M5878 is indicated by mollusks that are either 

still living today or are closely related and perhaps 

ancestral to living species: Thracia trapezoides, 

Lucinoma acutilineata [L. annulata], Megasurcula cf. 

M. wynoocheensis [Megasurcula spp.], and Macoma cf. 

M. astori [M. brota]. 

A smaller assemblage from about 110 m above the 

base of the Clallam (loc. M4681 and NP163) does not 

differ significantly in taxonomic composition from 

M4049. It consists mostly of bivalves suggestive of 

shallow inner sublittoral depths comparable to the 15-

to 35-m range inferred for locality M4049. 

The collection believed to be from near the top of the 

Clallam Formation (loc. M4678), on the basis of its 

location near the center of the synclinal structure between Pillar Point and Slip Point (see Gower, 1960), 

has only three mollusks that are not recorded from 

stratigraphically lower assemblages. One of these, a 

tellinid resembling the modern species Macoma secta 

which is an intertidal and upper inner sublittoral 

species (Coan, 1971), may be of bathymetric significance. However, the only- suggestion that this part of 

the section may be of appreciably shallower bathymetric facies than the lowest part of the Clallam comes 

from faunal data of Arnold and Hannibal (1913). They 

list a species of Anadara as the sole mollusk from a 

locality (NP162) at the Clallam coal mine which is 

within a few hundred metres, geographically, of locality M4683, and presumably at, or near the top of, the 

Clallam Formation. The occurrence of this bivalve, 

without any other mollusks, may be indicative of extremely shallow water, possibly intertidal, conditions 

inasmuch as Anadara in the northern part of its modern geographic distribution off Mexico today is characteristic of low taxonomic diversity assemblages from 

lagoonal and mangrove swamp environments (Parker, 

1963; Keen, 1971). 

PALEOCLIMATE 

Most of the still-living molluscan genera from the 

Clallam Formation are found today in temperate middle latitudes along the Pacific coast. None of the genera 

are restricted to cooler, more northern latitudes, but a 

few are found living in warm temperate to subtropical 

latitudes far to the south of western Washington. The 

appreciable representation of warm-water taxa in the 

Clallam assemblages suggests that water temperatures were significantly warmer at this latitude than 

they are today. The warm-water gastropods are Trochita, Natica, Neverita, Ficus, Semicassis, and Cancellaria. Some species of Cancellaria are referable to the 

warm-water subgenus Euclia (Addicott, 1970a). Only 

two of the pelecypods are of warm-water aspectAnadara and Dosinia. Both of these may have lived in 

cooler water assemblages during the middle and late 

Tertiary than they are found in today (Addicott, 1970b; 

Stanton and Dodd, 1970; Kern, 1973). By and large all 

of these warm-water taxa are limited to only one or two 

assemblages, and within these assemblages they are of 

relatively rare occurrence. This kind of occurrence 

suggests that they were not particularly characteristic 

of the Clallam assemblages and introduces the possibility of seas9nal recruitment from warmer water 
20 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

populations living to the south of the fossil localities 

(Addicott, 1966a, p. 14-15; Zinsmeister, 197 4). 

It seems doubtful that temperatures were as warm 

as would be indicated by a strict application of modern 

occurrences of the tropical to subtropical genera 

Trochita, Cancellaria (Euclia), Ficus, Dosinia, and 

Anadara s.s. that have their northernmost latitudinal 

occurrences in, or close to, the modern Surian mollusc~n province (Valentine, 1966) today, a biographic unit 

situated off the west coast of southern Baja California 

Mexico. Strict uniformitarian interpretation seem~ especially inappropriate because two of these taxa 

seem to have changed their temperature tolerance 

since the middle or late Tertiary during which time 

they occurred with relatively cooler water asse~blages. Moreover, the apparent lack of large populations of these warm-water genera suggests possible 

seasonal recruitment from warmer, more southern 

latitudes. Nevertheless, this element of distinctly 

warm-water taxa does argue for at least cycles of water 

temperature appreciably warmer than occur at this 

latitude today and, there are no data suggesting cooler 

water conditions. 

In view of the reclassification of the age of the Clalla~ fauna from provincial middle Miocene to late early 

MIOcene, the paleoclimatic diagram for the middle and 

late Tertiary of northwestern Washington (Addicott, 

1969) needs to be modified so as to position the Clallam 

data in the uppermost part of the ~~vaqueros" Stage 

rather than in the overlying ~~Temblor" Stage. This 

ch~nge remain~ consistent with the inferred early 

Oligocene to middle Miocene warming trend in the 

middle latitudes of the eastern North Pacific (Addicott, 

1969). Although the faunas of the Sooke and the Clallam Formations are now believed to be of early 

~iocene age, they are not coeval. The apparent warmIng that occurred from the time of deposition of the 

Sooke to the time of deposition of the Clallam is merely 

condensed into a shorter period. 

Neither the warm-temperate aspect of the molluscan 

assemblages inferred from modern distributions of 

component genera nor the apparent warming of the 

shallow inn~r sublittoral marine environment during 

the early MIOcene seem to be indicated by benthonic 

foraminiferal assemblages. Rau (1964) infers continuing cool-water conditions during the progressive shallowing of the bathymetric environment that took place 

during deposition of the upper member of the Twin 

River and the overlying Clallam Formation. The different interpretations based on the two kinds of 

benthic organisms seems perplexing, but it may be no 

more than an indication of a very shallow thermocline 

below which water temperature remained fairly constant but above which shallow inner sublittoral waters 

become progressively warmer during the late 

Oligocene and early Miocene. 

MOLLUSCAN PALEONTOLOGY 

The molluscan fauna of the Clallam Formation consists of 76 taxa identified from collections made by the 

writer and from fairly extensive Stanford University 

collections made by Harold Hannibal (Arnold and 

Hannibal, 1913) more than 60 years ago. Conventional 

systematic description of these mollusks is dispensed 

with in favor of taxonomic notes indicating significant 

morphologic features that either typify a taxon or distinguish it from similar species. Many of the taxa have 

been treated in Moore's (1963) monograph of the Astoria Formation of Oregon. Others were considered in a 

study of the California early and middle Miocene by 

Addicott (1970a). Where pertinent, synonyms not considered in Moore (1963) or Durham (1944) are noted 

and discussed. Original descriptions of previously 

named taxa identified here are referenced in the 

taxonomic notes. 

Newly described species and other species that appear to be undescribed but that are represented by 

material inadequate for formal description are treated 

more thoroughly (table 7). 

Practically all the mollusks from localities in the 

Clallam Formation are illustrated. Also illustrated are 

some of Reagan's (1909) specimens (table 1) from the 

Clallam that were originally figured by line drawings 

most of which are crudely drawn and extremely dif~ ficult to relate to actual fossil material. 

The systematic flow is patterned after the familial 

classification of gastropods by Taylor and Sohl (1962) 

and of bivalves by McCormick and Moore (1969) that is 

based on the earlier classification of Newell (1965). The 

check list of species from the Clallam Formation (table 

2) is arranged in the same sequence and may be used 

TABLE 7.-New species of mollusks described here and other species 

believed to be new but represented by material that is inadequate for 

formal description 

Gastropods: 

Trochita n. sp. 

Semicassis pyshtensis n. sp. 

M olopophorus n. sp. aff. M. newcombei (Merriam) 

Priscofusus goweri, n. sp. 

Priscofusus slipensis, n. sp. 

Ophiodermella olympicensis, n. sp. 

Pelecypods: 

Modiolus n. sp.? aff. M. restorationensis Van Winkle 

Mytilus n. sp. aff. M. tichanouitchi Makiyama 

Solamen snauelyi, n. sp. 

M acoma n. sp.? Moore 

Macoma n. sp. aff. M. secta (Conrad) 
GASTROPODS 21 

as a generalized index for locating taxonomic notes in 

this section. 

GASTROPODS 

TURRITELLIDAE 

Turritella oregonensis (Conrad, 1849) [pl. 1, figs. 10, 

11, 17]. Specimens of this small Turritella occur in 

localities near the top of a measured section on the 

west flank of the anticline near Pillar Point. They have 

a pair of strong primary spirals in the anterior part of 

the whorls and a single strong primary spiral rib in the 

posterior part (pl. 1, figs. 11, 17). This sculptural pattern is different from other figured specimens of this 

species (Merriam, 1941, pl. 20, figs. 17, 19, 20; Moore, 

1963, pl. 1, figs. 9-12; Addicott, 1970a, pl. 2, fig. 15), all 

of which have clearly differentiated pairs of primary 

and secondary spiral ribs. Nevertheless, Moore (1963, 

p. 25) states that uAbove the paired spirals may be 1 or 

occasionally 2 secondary spirals" indicating that three 

rather than four ribs may be the more common pattern. Accordingly, the Clallam specimens are identified as T. oregonensis rather than as a new species. 

In the Newport Embayment of northwestern Oregon, Turritella oregonensis occurs in the upper part of 

the Nye Mudstone (USGS loc. 15965) and in the Astoria Formation. These are indicative of an early to 

middle Miocene provincial range. 

EPITONIIDAE 

Epitonium clallamense Durham (1937) [pl. 1, figs. 8, 

13]. Specimens from locality M4413 near Slip Point 

have 9 axial ribs, falling within the range of 8 to 10 

ribs described by Durham (1937, p. 491, pl. 56, figs. 27, 

28). The types of this species are from the east end of 

Clallam Bay (Addicott, 1970a, p. 7 4), presumably from 

the lower part of the Clallam Formation because reconnaissance study of this area indicates that strata 

referable to the Clallam are exposed during the lowest 

seasonal tides. This species also occurs in an old collection from exposures immediately east of Slip Point (SU 

loc. NP89), very close to the broadly defined type locality. This species is restricted to the Clallam Formation 

in northwestern Washington. It occurs in the presumably coeval faunas of the Jewett Sand in central 

California (Addicott, 1970a) and the upper part of the 

Poul Creek Formation of the Gulf of Alaska (Kanno, 

1971). Its earliest occurrence is in the lower Miocene 

Sooke Formation of Vancouver Island (Addicott, 

1970a) and not in probable middle Oligocene strata as 

initially reported (Durham, 1937, p. 491). 

CALYPTRAEIDAE 

Trochita n. sp. [pl. 1, figs. 9, 12, 18]. One of the most 

commonly occurring gastropods in the Clallam Formation is a moderately coarse ribbed calyptraeid (pl. 1, 

figs. 12, 18) that is conspecific with a poorly known 

taxon from the Astoria Formation of Oregon, Trochita? 

n. sp.? Moore (1963, p. 26, pl. 1, fig. 23). In profile, 

specimens vary from nearly smooth to slightly shouldered. This is clearly an undescribed species but the 

specimens from the Clallam and the known specimens 

from coastal Oregon (Moore, 1963) and southwestern 

Washington (Wolfe and McKee, 1972) are too poorly 

preserved to adequately determine surficial sculpture 

and permit formal description. Trochita n. sp. resembles, somewhat, the modern tropical eastern Pacific 

species T. spirata (Forbes) and T. trochiformis (Born). 

Trochita n. sp. is much flatter and, although all available specimens are decorticated to varying degrees, the 

spiral sculpture is much more subdued. An early 

Miocene species T. sookensis (Clark and Arnold, 1923, 

p. 168, pl. 36, figs. 1 and 2) from the southwestern coast 

of Vancouver Island is distinguished from Trochita n. 

sp. by its finer and more numerous radiating ribs. The 

spire of T. sookensis species is of variable height; 

specimens from USGS locality M4060 are very low 

spired, comparable in this respect to Trochita n. sp. 

Another poorly preserved early Miocene species from 

California, Trochita cf. T. spirata (Forbes) (Addicott, 

1970a, p. 61-62), has coarser spiral sculpture than 

Trochita n. sp. and is unusually strongly shouldered. 

The common Miocene and Pliocene species T. filosa 

(Gabb, 1866, p. 15, pl. 2, figs. 25, 25a) has extremely 

fine spiral ribs, at least three times as many as 

Trochita n. sp. 

Crepidula praerupta Conrad (1849) [pl. 1, figs. 1, 22; 

pl. 2, fig. 24]. This species, occurring in several collections from the Clallam Formation, is externally similar to C. princeps Conrad, with which it occurs in the 

Clallam, but the internal septum is different. The external morphology of these two species is so variable, 

that it cannot always be used to distinguish them. On 

specimens of C. praerupta the insertions of the internal 

septum are approximately equidistant from the beak 

(pl. 1, fig. 1) whereas on C. princeps the edge of the 

septum defines a broadly open ~~s" and the insertions of 

the septum are at unequal distances from the beak (pl. 

1, fig. 7). Crepidula praerupta ranges from the early 

Miocene (Loel and Corey, 1932; Kanno, 1971) to the 

late Miocene (Moore, 1963). 

Crepidula princeps Conrad (1855) [pl. 1, figs. 6, 7]. A 

few deformed specimens of this moderately large C repidula occur in the Clallam. The strongly curved septal 

margin of this species (pl. 1, fig. 7) is one of the most 

distinctive specific characters. Crepidula princeps 

ranges froin the early Miocene to the Pleistocene along 

the Pacific coast (Addicott, 1970a, p. 64). This is the 

first record of C. princeps from the Pacific Northwest 
22 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

States. A moderately large, suborbicular Crepidula 

from the Sooke Formation of southwestern Vancouver 

Island, British Columbia, Canada (USGS loc. M4060), 

has the same septal configuration as C. princeps; it 

may represent this species, but the weakly inflated, 

suborbicular shell and the blunt apex suggest that it is 

a distinct species, possibly C. sookensis Clark and 

Arnold. 

Crepidula rostralis (Conrad, 1865) [pl. 2, figs. 23, 25]. 

The Clallam record of this species constitutes another 

range extension; it was previously known only from 

provincial middle Miocene strata (Addicott, 1970a). 

The illustrated specimen is deformed, as are most of 

the specimens of Crepidula from the Clallam. It is 

slender and elongate during the early stages of growth; 

the flattening is inferred to have been caused by subsequent deformation. This specimen has the pointed 

beak overhanging, or extending beyond, the aperture; 

this beak is characteristic of C. rostralis and enables 

this species to be readily differentiated from other 

species. 

Crepidula sp. [pl. 1, fig. 23]. A small Crepidula with 

an orbicular aperture and a very high, more or less 

vertically oriented beak. It seems to be distinct from 

other species in the Clallam Formation. The septal insertions are almost opposite each other. Since this is a 

very small, presumably immature, specimen, it could 

be an aberrant form of one of the other Clallam 

species-C. praerupta-which has similar septal insertions. 

NATICIDAE 

Natica cf. N. clarki Etherington (1931) [pl. 1, figs. 19, 

27, 28]. A few small naticids from the Clallam resemble the early and middle Miocene species N. clarki 

Etherington (1931, p. 93, pl. 12, fig. 12). These specimens have a well-developed, fairly broad umbilical callus that is unlike the callus on the holotype but comparable to the calluses of other specimens included in 

this species by Marincovich (1973, p. 235--236). 

Natica vokesi Addicott (1966b) [pl. 1, figs. 14-16]. 

This is the most common naticid in the Clallam. 

Specimens have a slender umbilical callus reflecting a 

broad, but indistinct, funicular rib comparable to type 

material from Oregon (Addicott, 1966b, p. 638-639, pl. 

77, figs. 2-5). Many of the large, undetermined naticids 

from localities in the Clallam probably are this species, 

but the preservation is too poor to permit specific identification. 

Neverita jamesae Moore (1963) [pl. 1, figs. 4, 5, 20, 

24]. A poorly preserved specimen (pl. 1, fig. 24) from 

USGS loc. M4684 has the widely open umbilicus, small 

bilobed callus, and broad apical angle characteristic of 

this species (Moore, 1963, p. 28-29, pl. 2, figs. 5, 15, 19). 

This species was identified by Arnold and Hannibal 

(1913, p. 588, loc. NP161) as t'Polinices saxea Conrad." 

P. saxea Conrad is a doubtful species that cannot be 

recognized because the type material is lost and the 

original description and illustration are vague (Moore, 

1963, p. 28). 

Polinices victorianus Clark and Arnold (1923) [pl. 1, 

fig. 25]. This early to middle Miocene species is known 

from only two localities in the Clallam. It is characterized by a narrow umbilical opening with a distinct, 

somewhat enlarged umbilical callus (Clark and Arnold, 1923, p. 170, pl. 33, figs. 1 and 5). As is the case 

with the other Clallam naticids, it may be represented 

by poorly preserved, specifically indeterminate material in other Clallam collections. 

Sinum scopulosum (Conrad, 1849) [pl. 1, figs. 21, 26]. 

Specimens of this long-ranging naticid are generally 

preserved as internal molds. Often the fine spiral 

sculpture is imprinted on these steinkerns (pl. 1, fig. 

21). 

CASSIDIDAE 

Semicassis pyshtensis, n. sp. 

Plate 1, figures 2, 3 

This fairly well-preserved cassidid has a low spire 

consisting of about four whorls; the penultimate whorl 

has prominent protractive axial ribs that are stronger 

than the straplike spiral ribs. These axial ribs are very 

subdued on the body whorl tending to be replaced by 

very faint irregular lines of growth. Spiral sculpture on 

the body whorl consists of 15 straplike ribs that are 

strongest toward the base. These are separated by fine 

secondary spirals. The face of the body whorl immediately adjacent to the aperture was covered by an 

apparently thin callus, a part of which is preserved on 

the fossa and on the base of the whorl. 

The holotype (USNM 215928) is from USGS locality 

M4414. It is 42 mm high and 28 mm wide. 

Semicassis pyshtensis differs from other middle and 

late Tertiary species from Oregon and Washington 

principally by its unique rib count. It is most similar to 

S. aequisulcatum (Dall, 1909, p. 63-64, pl. 5, figs. 1, 4), 

a late Miocene species from Oregon and southwestern 

Washington but differs from S. aequisulcatum in having 15 rather than 19 spirals. S. pyshtensis seems to 

form an evolutionary link between this finely 

sculptured late Tertiary species and the coarsely 

ribbed Oligocene species S. iani (Schenck, 1926, p. 80, 

pl. 13, figs. 8-11) which has only 11 spiral bands on the 

body whorl. 

S. aequisulcatum and S. iani were previously assigned to Phalium (Schenck, 1926, Weaver, 1942). 

Morphologically they are much closer to species of 
GASTROPODS 23 

Semicassis from Japan. The Japanese species have a 

very thin parietal callus that is smooth except for spiral plaits near the base of the apertural margin (Habe, 

1964, p. 69-70, pl. 21). The Japanese species are from 

the inner sublittoral zone, 10--100 m. Semicassis pyshtensis differs from the modernS. centiquadrata (Valenciennes), a very shallow water species from the Panamic molluscan province (Keen, 1971, p. 501, fig. 949), 

in lacking a granulated or pustulose callus surface. 

FICIDAE 

Ficus modesta (Conrad, 1848) [pl. 1 figs. 29, 30]. This 

bulbous, finely sculptured species is definitely known 

from only one of the collections studied during this 

investigation. Mature specimens reach a moderately 

large size and are smooth except for spiral sculpture of 

alternating fine and ultrafine ribs crossed by fine axial 

lines of growth. The intersection of these axial· and 

spiral systems produces a finely reticulate network. 

The relatively smooth exterior of this species permits 

differentiation from the coarsely noded Trophosycon 

clallamensis (Weaver) (pl. 1, fig. 31) which also occurs 

in the Clallam Formation. Ficus modesta occurs in the 

middle Miocene part of the Astoria Formation of 

southwestern Washington (Etherington, 1931; Addicott in Wolfe and McKee, 1972) and coastal Oregon 

(Moore, 1963). 

Trophosycon clallamensis (W~aver, 1912) [pl. 1, fig. 

31; pl. 2, fig. 34]. A small specimen with an unusually 

broad body whorl and broad apical angle was collected 

from near Slip Point (USGS loc. M4051). It has two 

prominent rows of nodes and a few relatively strong 

spiral ribs. These features distinguish it from Ficus 

modesta which is doubtfully recorded from the same 

locality. Trophosycon clallamensis resembles the widespread early Miocene to Pliocene species T. kernianum 

(Cooper), but it differs from T. kernianum in having a 

broader body whorl and weak, vertically elongated 

nodes (Addicott, 1970a, p. 75). 

MURICIDAE 

Trophonopsis sp. [pl. 2, fig. 20]. An incomplete external mold of the body whorl of a minute gastropod 

from loc. M4677 near Slip Point has well-preserved 

sculpture characteristic of Trophonopsis. The body 

whorl is angulated a short distance below the suture, 

the somewhat sinuous axial ribs are bladelike, and 

there is a long anterior canal. This may be the earliest 

record of the muricid genus along the Pacific coast. The 

earliest previous record seems to be from the late 

Miocene of the Cuyama Valley area of the central 

California Coast Ranges (Eaton and others, 1941, pl. 2, 

fig. 4). 

NEPTUNEIDAE 

Ancistrolepis rearensis (Clark, 1932) [pl. 3, fig. 26]. 

Only one specimen of this neptuneid has been collected 

from the Clallam. This species is characterized by a 

rounded whorl profile and a subsutural spiral rib 

situated high on the body whorl. The presence of the 

subsutural spiral rib distinguishes it from the presumably ancestral Oligocene species, A. clarki Tegland 

(1932, p. 131, pl. 12, fig. 14) on which this rib is indistinct from the suture (Durham, 1944, p. 177). Ancistrolepis clarki teglandae Durham (1944, p. 177, pl. 17, 

fig. 2) was shown by Kanno (1971, p. 118-119, pl. 13, 

figs. 5, 9; pl. 14, figs. 4-6) to be a junior synonym of this 

species. The occurrence of A. rearensis in the Clallam 

constitutes a range extension from the early Miocene 

Echinophoria apta zone of Durham (1944) from which 

it was previously known in the conterminous United 

States. The occurrence in the upper part of the Poul 

Creek Formation presumably is coeval judging by the 

co-occurrence with the~~." apta (see Kanno, 1971). 

Bruclarkia yaquinana (Anderson and Martin, 1914) 

[pl. 2, figs. 5, 7-9]. This species, the most commonly 

occurring of the two species of Bruclarkia in the Clallam Formation, is characterized by four, or sometimes 

five, coarsely noded spiral cords on the body whorl. The 

cords become progressively weaker toward the base of 

the whorl. The body whorl is bordered posteriorly by a 

well-developed subsutural collar on both small and 

large individuals. Specimens from near the base of the 

Clallam are identical to material from the lower 

Miocene of the San Joaquin basin in California (Addicott, 1970a, pl. 10, figs. 8, 12, 13). As recognized here, 

B. yaquinana is a small species. A large doubtfully 

identified internal mold (pl. 2, fig. 5) from the vicinity 

of Slip Point has very coarsely noded spiral cords similar to B. yaquinana but the cords are more widely 

spaced. Since the earlier ontogenetic stages of this 

specimen are not preserved, definitive comparison with 

B. yaquinana cannot be made. 

Bruclarkia oregonensis (Conrad, 1848) [pl. 2, figs. 

1-3]. This is a larger, more rounded species which differs from B. yaquinana, with which it sometimes occurs, in having uniformly finer spiral sculpture 

through all stages of growth. Nevertheless, differentiation of the two species is sometimes very difficult. 

Specimens from locality M4051, for example, seem to 

link these two species. A few of these specimens are 

clearly B. yaquinana (pl. 1, fig. 9). Other specimens 

seem to more closely resemble B. oregonensis (pl. 2, 

figs. 4, 6, 19). Still others have intermediate sculptural 

characteristics. The observed stratigraphic relation between these two species in central California (Addicott, 

1970a, p. 91) is not so clearly evident in northwestern 
24 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

Washington. It is suggested in a general way, however, 

by the almost exclusive occurrence of B. oregonensis at 

the top of the formation and by the decided prevalence 

of specimens of B. yaquinana at, and near, the base. 

Bruclarkia oregonensis is best represented by material from near the top of the Clallam Formation (loc. 

M4678). These specimens (pl. 2, figs. 1-3) are relatively 

large, are weakly sculptured, and have a poorly developed subsutural collar, if any at all. They are very 

similar to specimens from the Astoria Formation of 

southwestern Washington (Etherington, 1931, pl. 11, 

figs. 1, 3, 4, 7). 

Molopophorus n. sp. aff. M. newcombei (Merriam, 

1897) [pl. 2, fig. 16]. The external mold of a 

Molopophorus from the basal part of the Clallam near 

Pillar Point (loc. M5879) seems to be an undescribed 

species. It is most closely allied, morphologically, toM. 

newcombei (Merriam, 1897, p. 65), an early Miocene 

species from the Sooke Formation of nearby Vancouver 

Island, British Columbia. When compared with M. 

newcombei (pl. 2, figs. 10, 11), the Clallam specimen 

has generally weaker sculpture with both fewer spiral 

and axial ribs. Besides being weaker and more widely 

spaced, the spiral ribs of M. n. sp. aff. M. newcombei 

(Merriam) are obsolete on the posterior quarter of the 

body whorl. This apparently new species differs from 

the middle Miocene species M. matthewi Etherington 

(1931, p. 97, pl. 13, figs. 3, 6, 8, 9, 13) in having a 

sculptured body whorl and a well-developed subsutural 

collar. Molopophorus n. sp. may possibly provide an 

evolutionary link between the early Miocene M. newcombei and the middle Miocene M. matthewi. 

M olopophorus does not seem to be closely related to M. 

anglonana (Anderson, 1905, p. 205, pl. 16, figs. 7 4-76), 

an early and middle Miocene species characterized by a 

flat body whorl segment bordered by a noded subsutural collar and a noded basal angulation. 

FUSINIDAE 

Priscofusus aff. P. geniculus (Conrad) Moore (1963) 

[pl. 2, fig. 12]. Two deformed and incomplete fusinids 

from the lower part of the Clallam Formation appear to 

be conspecific with this undescribed species of Priscofusus from the Nye Mudstone (Snavely and others, 

1969b, pl. 1) south of Newport, Oreg. The body whorl of 

this taxon is unusually strongly angulated, and it has 

a relatively long, gently inclined subsutural slope. 

Available specimens are too incomplete to permit formal description of this species, which appears to be 

restricted to the late early Miocene of the Pacific 

Northwest States. 

Priscofusus goweri, n. sp. 

Plate 2, figures 14, 17, 18, 21 

Fairly abundant specimens of Priscofusus from 

localities on the west flank of the anticline near Pillar 

Point appear to be different from known species of this 

genus. These specimens are characterized by about 15 

vertically oriented axial ribs that occupy the upper 

half of the body whorl. The axial ribs extend from suture to suture on the penultimate whorl. The body 

whorl carries about 20 fine spiral cords; secondaries 

are intercalated between the uppermost of these. 

The holotype (USNM 215962) is from USGS locality 

M4049. It is 18 mm high and 8 mm wide. Paratypes 

(USNM 215960, 215961, 215963) from this locality 

range from 16 to 23 mm in height and from 8 to 12 mm 

in width. 

This species is named in recognition of Howard 

Gower who completed the first detailed geologic mapping of the Clallam Formation (Gower, 1960). 

This species seems closest morphologically to Priscofusus clarki Kanno (1971, p. 122--123, pl. 13, fig. 8, pl. 

14, figs. 8, 9, 15) from Alaska and P. stewarti (Tegland, 

1933, p. 129-130, pl. 12, figs. 4-8) from Washington. 

The holotype ofP. clarki (Kanno, 1971, pl. 3, fig. 8), the 

only well-preserved specimen illustrated, has angulated whorls unlike P. goweri and unlike Clark's (1932, 

p. 833, pl. 20, figs. 1-3) Fusinus cf. F. hannibali Clark 

and Arnold, which Kanno included as a synonym of his 

recently named Alaskan species. Clark's specimens, 

although poorly preserved, have a rounded whorl profile and a lower rib count (see illustrations in Addicott 

and others, 1971, figs. 2a, 2d-2f). Priscofusus goweri 

differs fromP. stewarti in having axial ribs rather than 

nodes, or elongated nodes, on the shoulder of the body 

whorl. Moreover, the whorls are rounded rather than 

angulated in profile. The axial ribs on P. goweri are 

narrower and more numerous than on P. hannibali 

(Clark and Arnold, 1923, pl. 30, figs. 1, 2), an early 

Miocene species from the Sooke Formation of southwestern Vancouver Island, British Columbia. It seems 

most likely that Clark's (1932) poorly preserved specimens are conspecific with P. hannibali, as originally 

indicated. 

Priscofusus slipensis, n. sp. 

Plate 2, figure 13 

A well-preserved, nearly complete specimen of Priscofusus from exposures near Slip Point is conspecific 

with Moore's (1963, p. 42, pl. 6, figs. 8, 11) Priscofusus 

n. sp.? This species is characterized by strongly angulated whorls. On the penultimate whorl, the axial ribs 

extend from suture to suture; at the medial angulation, 

they form a thin, spirally elongated node. On the lower 

two thirds of the penultimate whorl, fine secondary 

spiral cords alternate with the primary spiral cords. 

The body whorl has 12 vertically oriented axial ribs 
GASTROPODS 25 

that are strongest in the central part of the whorl just 

below the angulation. These ribs quickly fade out 

above the angulation and do not reach the suture. Spiral sculpture on the slightly concave subsutural shoulder consists of finely beaded primary spiral cords that 

are separated by fine secondary threads of variable 

strength. The same pattern continues below the angulation with the infrequent addition of a tertiary spiral 

thread. 

The holotype (SUPTC 154049) is from University of 

Washington locality 490. It is 27 mm high and 16 mm 

wide. 

The sculpture of Priscofusus slipensis is identical to 

that of the specimen from near Spencer Creek, Lincoln 

County, Oreg., described by Moore (1963, p. 42, pl. 6, 

fig. 11) as Priscofusus n. sp.? This species differs from 

the known species of Priscofusus from the eastern 

North Pacific margin in having vertically elongated 

nodes that extend across the penultimate whorl and 

across the medial third of the body whorl. Its occurrences here and in the Astoria Formation of Oregon 

define a late early Miocene to middle Miocene range. 

Priscofusus hannibali (Clark and Arnold, 1923, p. 158, 

pl. 30, figs. 1, 2) from the lower Miocene Sooke Formation of Vancouver Island is similar toP. slipensis but 

differs in having rounded axial ribs that extend from 

the suture to near the base of the body whorl. 

Priscofusus cf. P. stewarti (Tegland, 1933) [pl. 2, fig. 

15]. A small crushed specimen with angulated and 

strongly noded whorls resembles the early Miocene 

species P. stewarti from the upper Oligocene type 

Blakeley Formation near Seattle, Washington. The 

angulation on the body whorl is relatively close to the 

suture. The angulated and strongly noded whorls differentiate P. stewarti from P. goweri n. sp. from the 

same locality. If correctly identified asP. stewarti, this 

occurrence constitutes a range extension from the 

upper Oligocene Echinophoria rex zone (Durham, 

1944). 

VOLUTIDAE 

Musashia indurata (Conrad, 1849) [pl. 3, fig. 27]. An 

undoubted specimen of the coarsely ribbed volute, 

M usashia indurata, was collected from the basal part of 

the Clallam Formation near Pillar Point (loc. M4050). 

The axial ribs are well developed on the spire but 

weaker and irregularly spaced on the body whorl. 

About 18 axial ribs occur on the last half of the penultimate whorl and the first half of the body whorl. This 

rib count is the same as that on specimens of M. indurata from the Astoria Formation of Oregon (Moore, 

1963,p.43-44,pl. 7,figs. 1-9, 11;pl. S,figs. 1-5).Faint 

spiral sculpture is evident on the upper part of the body 

whorl of the Clallam specimen, and the ribs show the 

characteristic curvature just below the suture. 

Musashia corrugata (Clark, 1932, p. 831-832, pl. 21, 

figs. 4, 5, 11) from the Gulf of Alaska has fewer axial 

ribs than M. indurata, about 13-15 (Kanno, 1971, 

p. 125), and a much more slender shell. The Alaskan 

species is reported from the Oligocene and early 

Miocene (Kanno, 1971, p. 126); the earlier provincial 

occurrence of M. corrugata and its morphological 

similarities toM. indurata suggest that it could be the 

precursor of the early to middle Miocene species. 

M usashia indurata had previously been recorded 

only from the provincial middle Miocene. The Clallam 

record constitutes a definite range extension from the 

middle Miocene into the provincial early Miocene. 

M usashia indurata was doubtfully reported from the 

lower Miocene of the southern San Joaquin basin on 

the basis of fragmental material (Addicott, 1970a, 

p. 105, pl. 13, fig. 8). 

CANCELLARIIDAE 

Cancellaria birchi Addicott (1970a) [pl. 2, figs. 36, 

37]. A moderately high-spired cancellariid from the 

basal part of the Clallam is somewhat more spinose 

than specimens from the type locality in central 

California but is otherwise similar. This record of C. 

birchi constitutes a range extension; C. birchi was previously known only from the provincial middle 

Miocene of the southeastern San Joaquin basin, 

California. 

Cancellaria cf. C. oregonensis Conrad (1865) [pl. 2, 

figs. 2~28]. Poorly preserved specimens from two 

localities resemble a slender, relatively high-spired 

form of C. oregonensis Conrad from the Astoria Formation of Oregon (Moore, 1963, pl. 9, fig. 19). The axial 

ribs on the Clallam specimens are variable and generally fewer in number than on the material from the 

Astoria Formation. As with other species of Cancellaria from the Clallam, decortication makes species 

identification difficult. 

Cancellaria cf. C. siletzensis Hanna (1924) [pl. 2, fig. 

29]. This doubtfully identified cancellariid is based on a 

poorly preserved, deformed specimen from near the 

base of the Clallam Formation. It has the fine spiral 

sculpture and broadly rounded axial ribs characteristic 

of C. siletzensis; heretofore, C. siletzensis has been reported from the Astoria Formation of Oregon (Moore, 

1963, p. 44, pl. 9, figs. 2, 5). One of the Astoria 

localities, USGS locality 18901, may be from the uppermost part of the Nye Mudstone according to recent 

geologic mapping (Snavely and others, 1976) and of 

provincial early Miocene age. 

Cancellaria cf. C. simplex Anderson (1905) [pl. 2, 

figs. 30, 31]. Decorticated specimens from USGS locality M4049 near the base of the Clallam Formation 
26 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

have widely spaced, swollen axial ribs and a relatively 

large body whorl similar to the strongly sculptured 

form of C. simplex Anderson of Addicott (1970a, pl. 14, 

figs. 19, 20, 27), a Miocene species from central and 

southern California. These doubtfully identified 

specimens are much closer to C. simplex than they are 

to typical C. oregonensis from the Astoria Formation. If 

this doubtful occurrence could be validated by better 

material, it would constitute a range extension from 

the middle Miocene into the early Miocene. 

Cancellaria wynoocheensis Weaver (1916b) [pl. 2, 

figs. 32, 35, 38]. This is possibly the most distinctive 

cancellariid in assemblages from the Clallam Formation. It is characterized by fine spiral ribbing and 

numerous, closely spaced axial folds. There are considerably more axial folds on this species than on C. 

oregonensis with which it occurs in the Astoria Formation of Oregon and southwestern Washington. This 

record is a range extension from the provincial middle 

Miocene into the provincial early Miocene. 

TURRIDAE 

Xenuroturris antiselli (Anderson and Martin, 1914) 

[pl. 2, fig. 22, pl. 3, figs. 21, 23]. A poorly preserved, 

decorticated turrid from the Clallam has spiral ribbing 

identical to Moore's (1963, pl. 10, figs. 6, 12, 13, 15) 

~~Thesbia" antiselli (Anderson and Martin) from the 

Astoria Formation of Oregon. Moore's species was subsequently included as a coarsely ribbed form of X. antisell( (Anderson and Martin) by Addicott (1970a, 

p. 128). This form is ch:aracterized by five coarse, straplike spiral ribs on the body whorl. It has been doubtfully recorded from the lower Miocene Jewett Sand of 

the San Joaquin basin, California (Addicott, 1970a). 

?Rectiplanes sp. [pl. 2, fig. 33]. The external mold of 

a small, high-spired turrid seems to represent Rectiplanes. The proportions and the smoothly rounded profile of the whorls are similar to late Tertiary and 

Quaternary specimens from the Pacific coast. The 

closest described species from the Miocene of Oregon or 

Washington is Spirotropis washingtonensis 

Etherington (1931, p. 113, pl. 14, figs. 8, 22, 34) from 

the Astoria Formation. This species differs from ?Rectiplanes sp. in having a prominent, and sometimes 

noded, angulation on the body whorl and on some of 

the whorls of the spire. 

Ophiodermella olympicensis, n. sp. 

Plate 3, figures 1~20, 22 

A small turrid characterized by strongly developed 

spiral ribbing is described as Ophiodermella olympicensis n. sp. This species has distinctive characteristics and can therefore be differentiated from known 

Miocene turrids with little difficulty. It is known 

mostly from internal molds which provide an incomplete record of details of surface sculpture. The spire is 

sculptured by 4 spiral cords. Two primary spiral cords 

are flanked by a weaker spiral cord at the anterior 

suture and a fine spiral cord posteriorly. The rounded 

body whorl has eight spiral ribs that tend to be 

strongest on the medial part of the whorl. The uppermost spiral rib varies in strength and position with 

respect to the suture; sometimes it adjoins the suture 

but usually it is separate. This spiral rib and the next 

two spiral ribs may be separated from the lower five by 

a somewhat broader interspace (pl. 3, fig. 19). On many 

specimens, however, all the spiral ribs are of about 

equal length and may be equidistant from each other 

(pl. 3, fig. 18). The posterior notch is fairly deep and 

similar in configuration to species included in the 

genus by Powell (1966, p. 92). 

The holotype (USNM 215992) is from USGS locality 

M4051. It is 16 mm high and 6.5 mm wide. Paratypes 

from this locality (USNM 215993, 215994, 215995) 

range from 11.5 to 17 mm in height. 

This species is assigned to Ophiodermella because of 

the configuration of the posterior siphonal notch and 

because the general aspect of ribbing is similar to the 

Pliocene species 0. graciosana (Arnold, 1907, p. 430-

431, pl. 54, fig. 18). 

Ophiodermella olympicensis differs from 0. workensis (Etherington, 1931, p. 111-112, pl. 14, figs. 12, 24, 

26, 28, 30) from the Astoria Formation of southwestern 

Washington in having a rounded, rather than flattened, whorl profile and in having bolder spiral ribbing. Xenuroturris antiselli (Anderson and Martin) resembles this species somewhat but it differs in having 

an angulate body whorl with a concave profile between 

the angle and the posterior suture. 

Ophiodermella olympicensis is most likely to be confused with 0. muirensis (Clark and Arnold, 1923, 

p. 157-158, pl. 30, figs. 4--6), an older early Miocene 

species from the Sooke Formation, Vancouver Island, 

British Columbia. The Sooke species differs from 0. 

olympicensis in having more spiral ribs and in lacking 

the gap between the two prominent cords on the body 

whorl. 

A similar and possibly related species identified as 

Ophiodermella n. sp. by Addicott (in Wolfe and McKee, 

1972) occurs in the Astoria Formation of the Grays 

River quadrangle, southwestern Washington. This 

turrid has similar spiral sculpture (pl. 3, figs. 24, 25) 

but seems to differ in having a very wide interspace 

between the upper two or three spirals and the lower 

set of five. Because of these minor differences, it is 

doubtfully included with the Clallam species as 

Ophiodermella cf. 0. olympicensis. This species also oc-
PELECYPODS 27 

curs in the nearby Raymond quadrangle (USGS loc. 

M2287) in southwestern Washington. 

Megasurcula cf. M. wynoocheensis (Weaver, 1912) 

[pl. 3, figs. 16, 17]. A very well preserved Megasurcula 

from near Slip Point is similar to M. wynoocheensis 

(Weaver, 1912, p. 70-71, pl. 9, figs. 87-89), a middle 

Miocene species from the upper part of the Astoria 

Formation of southwestern Washington. It resembles a 

rather low-spired form of this species reillustrated by 

Weaver (1942, p. 527, pl. 98, fig. 8) but it differs in 

having a less concave subsutural slope. Another difference is in the much closer position of the nodes to the 

posterior edge of succeeding whorl. Megasurcula cf. M. 

wynoocheensis is differentiated from M. condonana 

(Anderson and Martin), a Miocene species from Oregon 

and California, on the basis of its much higher and less 

evenly conical spire. 

PELECYPODS 

NUCULIDAE 

Acila conradi (Meek, 1864) [pl. 3, figs. 1-3]. This 

Acila is of fairly common occurrence in the Clallam 

Formation. It has not been found in the stratigraphically lowest collections from the Clallam near Pillar 

Point (USGS locs. M4050 and M5879). The lowest occurrence is in a float collection near Slip Point representing an interval from 40 to 110m above the base of 

the formation (USGS loc. M4681). This species commonly has a secondary bifurcation of the radial rib 

pattern. Strong concentric ribbing is developed near 

the ventral margin on most of the larger specimens. 

This species has been recorded from many localities of 

Miocene age by Schenck (1936, p. 84) including one 

California early Miocene record from the Freeman Silt 

of Addicott (1970a), a unit that contains foraminiferal 

assemblages of early Saucesian age. A previous record 

from the Hoh Formation of Schenck (1936, p. 83-84) of 

the western Olympic Peninsula, Wash., represents a 

second early Miocene occurrence because it occurs 

there with the early Miocene index species Vertipecten 

fucanus (Dall). Although this species has long been 

thought to be restricted to rocks of provincial middle 

Miocene age, there are at least three early Miocene 

records, therefore the occurrence in the Clallam is not 

a range extension. 

NUCULANIDAE 

Nuculana calkinsi (Moore, 1963) [pl. 3, figs. 4, 6, 10, 

12-14]. This species occurs in molluscan assemblages 

from the finer grained strata of the Clallam Formation. 

Specimens are characterized by centrally located 

beaks, strongly inflated valves, and equally spaced 

ribbing. Many of the specimens are deformed, especially those from localities M4049 and M5878. Some 

individuals are larger than Moore's (1963) material 

from the Nye Mudstone and the Astoria Formation of 

Oregon, and others tend to be somewhat more elongate. 

Nuculana chehalisensis (Weaver, 1912) [pl. 3, fig. 

11]. A small species previously reported from the middle Miocene of southwestern Washington, Oregon, and 

central California (Etherington, 1931, p. 66) occurs in 

an assemblage from what appears to be the highest 

part of the Clallam Formation (USGS loc. M4678). 

This nuculanid is relatively high in proportion to its 

length and has a strongly concave posterior dorsal 

slope. It has been compared with N. eparchis Moore 

(1963, p. 55), but it differs from that species by its less 

elongate valves and, also, by its coarser concentric 

sculpture. 

Nuculana cf. N. elmana Etherington (1931) [pl. 3, 

figs. 8, 9]. Nuculanids from the lower 40 m of the Clallam Formation near Slip Point resemble the moderately elongate species N. elmana Etherington from the 

Astoria Formation of the Grays Harbor basin, southwestern Washington. The principal difference between 

them is the somewhat more pointed posterior of the 

specimens from the Clallam. This taxon differs from N. 

calkinsi (pl. 3, figs. 10, 12, 14) in having a long relatively straight posterior dorsal slope and in lacking the 

faint sinus in the anterior part of the valves. 

Other nuculanids that are too poorly preserved for 

specific identification occur in the collections from 

localities M4050, M4414, M4681, and M4683. 

Yoldia supramontereyensis Arnold (1908) [pl. 3, figs. 

7, 15]. Specimens from a few localities in the Clallam 

represent the initial record of this species north of the 

type area in the San Francisco Bay region of central 

California. Material from locality M4680 indicates 

some variation in the concavity of the posterior dorsal 

slope. The beaks tend to be situated medially which 

permits this species to be differentiated from the 

Oligocene to middle Miocene species Y. tenuissima 

Clark (1918, p. 78-79, pl. 8, figs. 5, 9). This record constitutes a range extension into the provincial lower 

Miocene; the holotype is from the unnamed sandstone 

of Dibblee (1966) which overlies the Page Mill Basalt 

that has been dated as 14.4 ±2.4 m.y. (Turner, 1970, p. 

106). Benthonic foraminifers from this sandstone are of 

provincial middle Miocene (Relizian or Luisian) age 

(Clark, 1968, p. 177). Until now all records of Y. supramontereyensis were from strata of provincial middle 

Miocene age (Loel and Corey, 1932). 

Undetermined, poorly preserved specimens ofYoldia 

from localities M4681, M4683, and M4684 may represent Y. supramontereyensis. 
28 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

SOLEMYIDAE 

Archarax dalli (Clark, 1925) [pl. 3, fig. 5]. Specimens 

of Solemya from the lowermost part of the Clallam 

Formation near Pillar Point (USGS loc. M4050) are 

identical to probable topotypes of A. dalli from the 

upper member of the Twin River Formation. The outline of the valves and the position of the beaks are the 

same. This species is difficult to distinguish from the 

middle Miocene species A. ventricosa (Conrad). Weaver 

(1942) and Tegland (1933) cite the more posterior location of the beaks on A. dalli as being the significant 

specific determinant. Tegland (1933, p. 103) separated 

A. ventricosa from A. dalli on the basis of two large 

quadrate specimens from the upper Eocene and lower 

Oligocene Keasey Formation that were later named A. 

willapaensis (Weaver, 1942, p. 21-22). According to 

Weaver (1942, p. 20), the length of the anterior segment of the dorsal margin averages 75 percent of the 

length of the shell on A. dalli, whereas on A. ventricosa 

it averages only 60 percent. This means of differentiation seems suspect because the position of the beaks on 

the lectotype of A. ventricosa is about 75 percent of the 

length of the dorsal margin (Moore, 1963, pl. 11, fig. 8). 

Although the two species are very similar, they do 

seem to differ in the outline of the valves. Specimens of 

A. ventricosa, including the paratype and the lectotype 

(Moore, 1963, pl. 11, figs. 8, 11), are much higher in 

proportion to their length than are specimens of A. 

dalli. A. dalli is known from the upper member of the 

Twin River Formation and the basal part of the Clallam. A. ventricosa is not known to occur in strata older 

than middle Miocene along the Pacific coast; a late 

Oligocene or early Miocene record attributed to Tegland (1933) by Moore (1963, p. 52) is in error. 

ARCIDAE 

Anadara aff. A. lakei (Wiedey, 1928) [pl. 5, figs. 8, 9]. 

Decorticated specimens of an Anadara from the lowest 

part of the Clallam Formation near Pillar Point (USGS 

locs. M4050 and M5879) are similar to A. lakei, a middle Miocene species from central California. Identification of these specimens is doubtful owing to their poor 

preservation. They have about 25 ribs that are grooved 

medially. ThisAnadara is similar to the late Oligocene 

to early Miocene species A. submontereyana (Clark, 

1918, p. 128--129, pl. 16, fig. 2) from California but has 

more radial ribs-25 rather than 22 to 24. Anadara 

devincta (Conrad), the common Miocene species from 

the Astoria Formation of Oregon and southwestern 

Washington which occurs stratigraphically higher in 

the Clallam Formation, can be readily differentiated 

from this species by its much higher rib count-29--32 

(Reinhart, 1943, p. 44). 

Anadara devincta (Conrad, 1849) [pl. 5, fig. 10]. This 

• 

Anadara occurs in strata that appear to be near the top 

of the Clallam Formation near the center of the 

syncline between Pillar Point and Slip Point (Gower, 

1960). This species is distinguished from A. aff. A. lakei 

(Wiedey), which occurs in the lower part of the Clallam 

Formation, by having a larger number of radial ribs 

about 29 rather than 25. As shown by Reinhart (1943), 

the number of radial ribs is a critical specific character 

in this genus. The ribs are split by two grooves in the 

anterior part of the valve and by a single groove in the 

medial and posterior parts (pl. 5, fig. 10). The present 

specimens are identical to the split-ribbed form of A. 

devincta of Moore (1963, p. 59--61) which occurs in both 

the Nye Mudstone (USGS locs. 18830, 18831, 18941, 

and 19050) and the Astoria Formation in the Newport 

Embayment, Oreg. 

GLYCYMERIDIDAE 

Glycymeris sp. [pl. 5, fig. 3]. Specifically indeterminate internal molds of Glycymeris occur at two 

localities (M4414 and M4684) in the Clallam Formation. The genus has not previously been recorded from 

this formation nor has it been found in the upper 

member of the Twin River Formation. 

MYTILIDAE 

Modiolus n. sp.? aff. M. restorationensis Van 

Winkle (1918) [pl. 5, fig. 5]. A rather small Modiolus 

with weakly inflated valves occurs in the lowermost 

part of the Clallam Formation (locs. M4050 and 

NP161). It is similar to M. restorationensis Van 

Winkle, a late Oligocene species from western 

Washington, but differs in having a convex, rather 

than straight or concave, dorsal margin and a less 

broadly flattened extremity. These differences suggest 

that it is an undescribed species, but there are too few 

specimens to rule out the possibility that it might be a 

form of M. restorationensis. 

Mytilus n. sp. aff. M. tichanovitchi Makiyama 

(1934) [pl. 5, figs. 1, 2, 16, 18]. An undescribed rugose 

mytilid from the Clallam Formation resembles Mytilus 

tichanovitchi Makiyama (1934, p. 134-135, pl. 5, figs. 

11, 12) from the Miocene ofHokkaido, Japan (pl. 5, fig. 

14), and M. ochotensis (Slodkewtisch, 1938, p. 117, pl. 

49, fig. 4, pl. 50, fig. 1), presumably a synonym of M. 

tichanovitchi from the Miocene of Kamchatka. The 

Clallam species has strongly inflated valves characterized by a broad umbonal angle, a flared dorsal margin, 

and a strong umbonal ridge together with a secondary 

ridge occupying the posterior part of the depression 

between the ridge and the dorsal wing (pl. 5, figs. 1, 2). 

The dorsal alation on specimens from the Clallam is of 

variable strength owing, in part, to deformation of 
PELECYPODS 29 

most of the specimens. The secondary ridge distinguishes the Clallam species from M. tichanovitchi. As 

noted by Allison and Addicott (1976), this Mytilus n. 

sp. also occurs in strata of provincial early Miocene age 

in central California and in strata of early middle 

Miocene age (Gladenkov, 1974) in western Kamchatka. The California occurrence is based on specimens from the southern San Joaquin basin that have 

been confused with M. middendorffi Grewingk (Addicott, 1965). Although the two species resemble each 

other superficially, the margins of the valves ofMytilus 

n. sp. are straight whereas those of M. middendorffi 

fold sinuously. The Kamchatka record is based on 

specimens figured by Il'ina (1963, pl. 11, figs. 1, 6) from 

the Kuluven Suite, possibly erroneously, as M. 

ochotensis Slodkewtisch and on an additional specimen 

from the same unit figured by Allison and Addicott 

(1976, pl. 2, figs. 2, 5). 

Solamen snavelyi, n. sp. 

Plate 4, figures 6, 9 

Previously undescribed elongate, strongly inflated 

specimens of Solamen similar to the Oligocene species 

S. porterensis (Weaver, 1912, pl. 14, fig. 116) are here 

named S. snavelyi. The elongate-ovate valves of this 

species are sculptured by 100 or more fine flat-topped 

ribs. In the medial part of the valve, these ribs are 

separated by very narrow interspaces. Near the anterior margin, the radial ribs are much finer and the 

interspaces are relatively wider. Irregularly spaced 

concentric growth lines, some of which are strongly 

constricted, occur at increasingly closely spaced intervals toward the ventral margin. 

The holotype (USNM 216008) is from USGS locality 

M4051. It is 14 mm long and 21 mm high. A paratype 

(USNM 216007) from USGS locality M4050 is 14 mm 

long and 19 mm high. 

Solamen porterensis, an Oligocene species from 

Washington, differs from S. snavelyi in having bifurcating radial ribs and more quadrate valves as indicated by a topotype (pl. 4, figs. 3, 11) from Porter Bluffs, 

Wash. Crenella cf. C. porterensis Weaver (Moore, 1963, 

p. 63, pl. 15, fig. 6) from the Astoria Formation of Oregon seems to belong to S. porterensis in view of its 

similar shape and pattern of bifurcating ribs. If so, it 

represents a range extension from the Oligocene ~~Lincoln" Stage and the lower part of the Matlockian or 

(~Blakeley" Stage (Durham, 1944) to the provincial 

middle Miocene. 

Solamen snavelyi also occurs in the Astoria Formation of southwestern Washington (Addicott in Wolfe 

and McKee, 1972, table 13, as Crenella cf. C. porterensis Weaver). The provincial range of this species is 

from the early Miocene to the middle Miocene. 

This species is named for Parke D. Snavely, Jr., in 

recognition of his contributions toward deciphering the 

geological history of western Oregon and Washington. 

PECTINIDAE 

Vertipecten fucanus (Dall, 1900) [pl. 4, figs. 1, 2, 5, 7, 

10, 12]. This pectinid is the most characteristic mollusk 

in assemblages from the Clallam Formation. It is usually represented by disassociated valves, complicating, 

somewhat, differentiation from fragmental specimens 

of the somewhat similar giant pectinid, Patinopecten 

propatulus (Conrad), a middle Miocene species from 

the Pacific Coast. The left valves of these species are 

distinct but the ribbing of the right valves, as noted by 

Moore (1963, p. 65), is similar. There are, however, 

important morphological differences between the right 

valves of these two giant pectinids that have not been 

previously considered. The ears of V. fucanus, for 

example, are relatively much larger than those of P. 

propatulus. Specifically, the length of the ears on 

specimens of V. fucanus is considerably more than half 

the width of the valves whereas on P. propatulus the 

ears are less than half the width of the valves. A second 

difference is the initially flat or slightly concave profile 

of right valves of V. fucanus during early growth 

stages. This profile contrasts with the regularly convex 

profile of P. propatulus. In adult specimens of V. 

fucanus, the initially flat profile of V. fucanus usually 

develops into a gently convex profile similar to that of 

P. propatulus. Finally, the ribbing on right valves ofV. 

fucanus is much more irregular than on P. propatulus, 

especially in the lateral areas. Many specimens of V. 

fucanus have one or more irregular ribs in the medial 

part of the disk and most specimens have a widening 

and deepening of the medial interrib corresponding to 

the strongly raised opposing rib of the left valve. 

Some earlier workers (Arnold and Hannibal, 1913; 

Arnold, 1906; and Weaver, 1916a) identified both of 

these large pectinids in assemblages from the Clallam. 

Study of available collections reinforces the apparent 

conclusion of later investigators (Etherington, 1931; 

Durham, 1944) that there is only one large pectinid, V. 

fucanus, in the Clallam. All the left valves examined 

are referable to V. fucanus because of the characteristic pattern of a strongly raised medial rib and somewhat less accentuated flanking ribs that divide the 

disk into quadrants. These valves also differ from those 

of P. propatulus in being much more convex. 

Specimens in the collections average about 80-90 

mm in greatest diameter. These averages are misleading because the relatively small specimens are easiest 

to collect. In the field, most specimens exceed 100 mm 
30 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

in maximum diameter, and there are several specimens in the stratigraphic collections that are as large 

as 110--120 mm. The right valves have 17 or 18 somewhat irregular flat-topped ribs. This valve also has a 

reticulate, or honeycombed, microsculpture that covers 

both the ribs and the interspaces. There are usually 15 

or 16 crested ribs on the left valves; the medial rib is 

much stronger than any of the others and most are 

scaly or imbricated. Both valves have fine, irregular 

lateral ribs. 

As indicated elsewhere in the text, Vertipecten 

fucanus seems to be a very useful species in biostratigraphic correlation of Miocene formations in the 

Pacific Northwest States. Its restricted stratigraphic 

occurrence in the Nye Mudstone of western Oregon 

and the Jewett Sand of central California is indicative 

of provincial early Miocene age. It also occurs in the 

Hoh rock assemblage of Rau (1973) along the western 

side ofthe Olympic Peninsula, Wash. (loc. M4146) with 

shallow-water mollusks that also occur in the Clallam 

and are presumably coeval. 

LUCINIDAE 

Lucinoma acutilineata (Conrad, 1849) [pl. 5, figs. 4, 7, 

15]. Scattered and usually poorly preserved specimens 

of this 1 ucinid occur in some parts of the Clallam Formation. As is characteristic of this species, the density 

of concentric lamellae is variable, but the spacing is 

equidistant over the greater part, if not all, of the 

valves (Moore, 1963, p. 70). This species is almost always preserved with articulated valves. It ranges from 

the middle part of the provincial Oligocene (Hickman, 

1969) to the middle Miocene (Addicott, 1973). It is 

difficult to distinguish this species from some of the 

late Oligocene specimens from the Blakeley Formation 

of Washington figured as L. hannibali (Clark) by Tegland (1933, pl. 8, figs. 10, 12). The holotype of L. hannibali (Clark, 1925, pl. 22, figs. 2, 4) differs from L. 

acutilineata in having less regularly rounded valves 

and much more anteriorly situated beaks. The early 

Miocene species L. columbiana (Clark and Arnold, 

1923, p. 144--145, pl. 25, fig. 2) that is from the Sooke 

Formation of Vancouver Island may be a synonym of L. 

acutilineata. 

THYASIRIDAE 

Conchocele disjuncta Gabb (1869) [pl. 6, fig. 7]. The 

essentially straight anterior margin of this species 

permits differentiation from the similar Tertiary 

species C. bisecta (Conrad) which has a concave anterior margin and more prominent umbones (Bernard, 

1972). Many Cenozoic molluscan specialists have considered C. disjuncta to be a junior synonym of C. 

bisecta (see, for example, discussions in Moore, 1963, 

and Bernard, 1972). Although C. disjuncta is sometimes treated as a deep-water taxon, a modern northeastern Pacific occurrence from only 10 m was described by Kanno (1971). Conchocele disjuncta occurs 

in collections from the lowest part of the Clallam Formation. 

UNGULINIDAE 

Felaniella sp. [pl. 5, fig. 17]. The outline of a small 

bivalve from locality M4413 is suggestive ofFelaniella, 

a fairly common genus in Oligocene and Miocene 

faunas from the Pacific Coast States. Felaniella parilis 

(Conrad) was reported from Slip Point, about a mile 

west of locality M4413, by Etherington (1931, checklist 

facing p. 31). 

CARDITIDAE 

Cyclocardia subtenta (Conrad, 1849) [pl. 5, fig. 12; pl. 

6, figs. 9, 10]. Specimens from the Clallam have about 

22 radial ribs that become narrower toward the posterior part of the valve. The outline of the valves is 

variable and the beaks usually are prominent. Cyclocardia castor (Dall, 1909, p. 116, pl. 11, figs. 1, 3) from 

the upper member of the Twin River Formation, on the 

east side of the mouth of East Twin River, has a similar 

rib count and valve outline. It may well be a synonym 

of C. subtenta, but according to Weaver (1942, p. 13~ 

140) it differs in having a more deeply impressed 

lunule and weaker but broader radial ribs. Cyclocardia 

yakatagensis (Clark) from the upper part of the Poul 

Creek Formation, Gl.llf of Alaska, may also be a 

synonym of this species. It has a similar rib count, 

23-25 radial ribs. The form named by Dall (1909, p. 

115) as ((Venericardia subtenta var. quadrata" from 

specimens collected near Slip Point in the vicinity of 

USGS locality M4413 Cone mile east of Clallam Bay") 

was differentiated from C. subtenta on the basis of its 

larger, more quadrate valves. Dall's taxon, however, 

falls within the range of variation of C. subtenta 

(Moore, 1963, p. 70). 

CARDIIDAE 

Clinocardium n. sp. aff. C. nuttalli (Conrad, 1837) [pl. 

5, fig. 13; pl. 6, fig. 8]. A few poorly preserved cardiids 

from the Clallam Formation may represent an undescribed species. Although decorticated, specimens of 

Clinocardium n. sp. appear to have had at least 18 

coarse ribs anterior of the posterior inflection. The ribs 

on one specimen (pl. 5, fig. 13) are broad and rather flat 

topped. The other specimens are decorticated to such 

an extent that the original rib configuration cannot be 

determined. The beaks are inclined as in other species 

of C linocardium. In all probability, this is the same 
PELECYPODS 31 

species as MoO're's (1963, p. 73, pl. 30, figs. 1, 2) 

Clinocardium aff. C. nuttalli (Conrad) from Coos Bay, 

Oreg. Clinocardium yakatagense (Clark, 1932, p. 813, 

pl. 18, fig. 8), a somewhat similar species from the middle Miocene part of the Yakataga Formation, Gulf of 

Alaska, has a similar rib count but differs at least from 

the best preserved specimen of Clinocardium n. sp. 

from the Clallam (pl. 5, fig. 13) in having crested 

rather than broadly rounded, or flat-topped, ribs. The 

other specimens from the Clallam are too poorly preserved to permit confident distinction from other middle Tertiary species. An early Miocene cardiid from the 

Sooke Formation of Vancouver Island, British Columbia, C. sookensis (Clark and Arnold, 1923, p. 145, pl. 

22, figs. 1 and 2), differs from Clinocardium n. sp. in 

having almost twice as many radial ribs. 

MACTRIDAE 

Spisula albaria (Conrad, 1848) [pl. 6, fig. 3; pl. 7, figs. 

2, 3, 11]. This moderately large mactrid is characterized by a concave anterior dorsal slope, a convex 

posterior dorsal slope, and prominent beaks that tend 

to be situated posterior to the midline of the valves. 

The anterior extremity is pointed; the posterior extremity is much broader. Moore (1963, p. 82--83, pl. 28, 

figs. 1-3, 5; pl. 31, figs. 9, 11) assigned all mactrids 

from the Astoria Formation of Oregon to this species, 

recognizing a broad range of variation in the outline of 

the valves. Reagan's (1909, p. 187, pl. 2, fig. 19) Mactra 

gibbsana Meek (pl. 7, figs. 2, 3) is a synonym of this 

species as originally noted by Dall (1922). The anterior 

part of the specimen is deformed. This species is one of 

the most commonly occurring and abundant bivalves 

in the Clallam Formation. It is easily differentiated 

from other Spisula from the Clallam by its characteristic elongate-trigonal valves. 

Spisula albaria goodspeedi Etherington (1931) [pl. 6, 

fig. 14; pl. 7, fig. 1]. This nearly equilateral trigonal 

mactrid was described from the upper Miocene Montesano Formation of Weaver (1912) of southwestern 

Washington. The unique outline of the valves permit 

differentiation from S. albaria, but in the context of the 

broad range of variation recognized by Moore (1963, p. 

82--83), it would very likely be treated as only a form of 

the latter species. This species also occurs in the middle Miocene part of the Astoria Formation of southwestern Washington (Etherington, 1931). 

Spisula c£. S. hannibali Clark and Arnold (1923) [pl. 

6, fig. 11]. This mactrid has an unusually broad apical 

angle and long, more or less straight, dorsal slopes. It 

is represented by poorly preserved material, consequently the identification is doubtful. Spisula hannibali has been reported from strata of provincial early 

Miocene age near Seattle that are correlated with the 

upper part of the ((Blakeley" Stage (Durham, 1944). 

The principal difference between S. hannibali and both 

S. albaria and S. albaria goodspeedi is the unusually 

broad apical angle. As in the case of S. albaria 

goodspeedi, it seems possible that this taxon could fall 

within the broad range of variation ofS. albaria recognized by Moore (1963, p. 82--83) although it was not 

included as a synonym of that species. Spisula 

equilateralis (Clark, 1932, p. 819-820, pl. 11, fig. 8), an 

early Miocene species from the upper part of the Poul 

Creek Formation, Gulf of Alaska (Kanno, 1971, p. 72), 

may be a synonym of S. hannibali but appears to differ 

in having relatively longer valves. 

Spisula sookensis Clark and Arnold (1923) [pl. 6, figs. 

1, 16]. Another Spisula originally described from the 

lower Miocene Sooke Formation of nearby Vancouver 

Island, Canada, occurs at a few localities in the Clallam. It is a large, thin-shelled mactrid similar in outline to the Miocene-to-Holocene species S. catilliformis 

(Conrad) (Packard, 1916, pl. 18, figs. 1, 2; Fitch, 1953, 

fig. 53). Both Spisula sookensis and S. catilliformis 

have a rib just below the posterior dorsal margin, but 

S. sookensis differs from S. catilliformis in having more 

quadrate valves with the beaks situated closer to the 

anterior extremity. It seems possible that some 

Miocene records of S. catilliformis from California 

(Loel and Corey, 1932, p. 170, 232, pl. 44, fig. 8; Packard, 1916, p. 286, pl. 9, figs. 1, 2) could be of this 

species. If so, a provincial early Miocene (Vaqueros 

Formation of Loel and Corey, 1932) to late Miocene 

(San Pablo Group of Clark, 1915) age would be indicated. 

Spisula sp. [pl. 6, fig. 6]. A specimen from locality 

M4049 is so different from the other species in the Clallam that it is treated, tentatively, as a separate taxon. 

It is most similar to S. albaria, but the outline of the 

valves differs from this commonly occurring species in 

the anterior location of the beaks. 

SOLENIDAE 

Solen conradi Dall (1900) [pl. 6, fig. 12]. A small Solen 

with a slightly convex ventral margin and a straight or 

slightly concave dorsal margin is conspecific with S. 

conradi Dall (1900, p. 953), a species originally described from the Astoria Formation of Oregon. The few 

specimens from the Clallam are from the lowest 240 m 

of the formation. Solen conradi ranges from the early 

Miocene to the middle Miocene (Moore, 1963). 

TELLINIDAE 

Tellina emacerata Conrad (1849) [pl. 7, figs. 5, 7, 10]. 

This is the most commonly occurring tellinid in the 

Clallam Formation. It can be readily differentiated 
32 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

from the other Clallam tellinids by the prominent, inclined internal rib in the anterior half of the valve (pl. 

7, figs. 5, 10). This feature is apparent on most of the 

Clallam specimens because practically all lack shell 

material. The plane of commissure is flexed posteriorly 

resulting in a slight bending of the valves. The surface 

is sculptured by very fine, evenly spaced concentric 

grooves. Reagan's (1909, p. 186--187, pl. 2, fig. 18) T. 

clallamensis is a synonym of this species; it is refigured 

on plate 7, figure 10. Tellina emacerata ranges from the 

early Miocene to the middle Miocene in Oregon and 

Washington. It may be represented by Tellina (Oudardia) sp. Kanno (1971, p. 75--76, pl. 10, figs. 4, 5) from 

the upper part of the Poul Creek Formation in the Gulf 

of Alaska region. In California, this species ranges 

from the late Oligocene to the late Miocene (Addicott, 

1973, p. 32). 

Macoma albaria Conrad (1849) [pl. 7, figs. 13-15, 17, 

20]. This small tellinid, characterized by posteriorly 

located beaks and valves that are weakly flexed posteriorly, occurs at a few localities in the Clallam Formation. Almost all the right valves of this species have 

been bored by gastropods. The right valve is the more 

strongly flexed of the two valves. The flexing and the 

position of the borings near the middle of the right 

valve suggest that this species lived very close to the 

surface and that the plane of commissure was oriented 

parallel to the sediment-water interface with the right 

valve above the left one. This species and two other 

small Macomas from Oligocene and Miocene formations in Oregon and Washington, M. twinensis Clark 

and M. arnoldi Tegland, are very similar. Both M. albaria and M. twinensis Clark (1925, p. 96, pl. 12, fig. 7) 

have posteriorly located beaks and are much less 

strongly flexed posteriorly. As an alternative to discrimination as separate species, it seems possible that 

the two taxa could be treated as forms of a variable 

species. Macoma arnoldi Tegland (1933, p. 119-120, pl. 

9, figs. 2-8), a small species of late Oligocene age, differs from these two in having higher, more trigonal 

shaped valves and more centrally located beaks (pl. 7, 

figs. 16, 19). Reagan's (1909, pl. 2, fig. 15) M. albaria 

could be M. arnoldi; as noted by Moore (1963, p. 50) it 

is not M. albaria. 

Macoma arctata (Conrad, 1849) [pl. 7, figs. 4, 6, 8, 14, 

18, 22]. The elongate valves of this large species are 

bent or flexed posteriorly as in the late Cenozoic 

species M. nasuta (Conrad); the. left valve is more 

strongly flexed than the right one. The beaks are located in the posterior part of the valve. Some specimens (pl. 7, figs. 8, 14), preserved with shell material 

or as internal molds, have faint radial ribbing in the 

anterior ventral part. Some of the best specimens are 

from locality M4051; the shell material has been 

leached but the exterior sculpture has been transferred 

to the internal molds and is fairly well preserved. This 

probably is the type locality for Reagan's (1909, p. 186, 

pl. 1, fig. 17) Tellina arctata var.juana. The holotype of 

this taxon is refigured on plate 7, figure 14. Specimens 

from near the base of the Clallam (loc. M4049) may 

represent the earliest occurrence of large species of 

Macoma in Oregon and Washington. Material identified as M. arctata from the uppermost part of the Lincoln Creek Formation (Armentrout, 1975) could be 

coeval; the associated assemblage contains only a few 

species, none of which are diagnostic of provincial age. 

This species appears in the provincial late Oligocene in 

California (Addicott, 1973, p. 33). Its highest stratigraphic occurrence in California, Oregon, Washington, 

and Alaska (Moore, 1963; Kanno, 1971; Addicott, 

1973) is in strata of middle Miocene age. This species 

also occurs in the western North Pacific where it has 

the same geological range. The oldest record is from 

the late Oligocene of Honshu Island, Japan (Kanno, 

1960); the youngest (ll'ina, 1963, p. 81) from middle 

Miocene (Gladenkov, 1972, p. 169) strata of Kamchatka, Russia. 

Macoma cf. M. twinensis Clark (1925) [pl. 6, fig. 5]. A 

few, small articulated tellinids from the Clallam Formation are doubtfully identified as Macoma twinensis. 

They are more elongate and have more centrally located beaks than the more commonly occurring specimens of Macoma albaria Conrad. Macoma twinensis 

was described from exposures of the upper member of 

the Twin River Formation about 2 miles west of Twin 

River (Weaver, 1942, p. 210). This species also differs 

from M. albaria in having more strongly flexed valves. 

Specimens of M. twinensis from near the base of the 

type section of Durham's (1944) Echinophoria apta 

zone (loc. M4032) are illustrated on plate 6 (figs. 2, 4, 

13, 15) and plate 7 (fig. 12). Identification of this 

species in the Clallam is doubtful because of the similarity toM. albaria and because the valves are not so 

strongly flexed as on undoubted specimens of M. 

twinensis. The latter condition could be due to deformation of the valves. Macoma twinensis ranges from 

the provincial late Oligocene to the early Miocene. The 

doubtful record of this species in the Clallam is the 

youngest in the Pacific Coast Tertiary. 

Macoma astori Dall (1909) [pl. 7, fig. 21]. Significant 

morphologic features of this taxon are its pointed and 

relatively strongly flexed posterior extremity, its long 

and nearly straight posterior dorsal margin, and its 

almost medially located beaks. One moderately large 

specimen from the Clallam (pl. 7, fig. 21) is almost 

identical to Dall's type specimen (see Moore, 1963, p. 

81, pl. 29, fig. 12). Macoma astori seems to be more 

similar to the late Tertiary and Quaternary species M. 
PELECYPODS 33 

nasuta (Conrad) than to any of the other bent-nosed 

0 ligocene and Miocene species from Oregon and 

Washington. Some paleontologists (Grant and Gale, 

1931, p. 369; Faustman, 1964, p. 22; Talmadge, 1972, 

p. 413) consider M. lipara Dall (1916), a Pliocene to 

Holocene species, to be indistinguishable from M. astori and, by inference, a synonym of this species. This 

treatment seems inadvisable in view of longer, and 

straight rather than convex, posterior dorsal margin of 

M. astori. Moreover, the right valve of M. astori is 

much more strongly flexed than that of M. lipara. 

Macoma sookensis Clark and Arnold (1923) [pl. 7, fig. 

23; pl. 8, figs. 1, 2, 5]. Left valves of a large, fairly thick 

shelled Macoma from the lowest 40-110 m of the Clallam Formation (USGS locs. M4681 and NP161) are 

identical to Clark and Arnold's (1923) species from 

nearby Vancouver Island, British Columbia. This 

species is similar toM. nasuta (Conrad), a commonly 

occurring modern taxon that ranges back into the 

Miocene. Like M. nasuta it has anteriorly located 

beaks and a ligamenta! nymph indicative of an elongate ligament. The overall shape of the valves is similar, but the valves of these specimens of M. sookensis 

are less strongly flexed and are broadly rounded, 

rather than pointed, posteriorly. This rounding plus 

the less strongly sloping posterior dorsal margin give 

the valves of this species a more quadrate outline than 

M. nasuta. Macoma sookensis seems to be restricted to 

strata of provincial early Miocene age. 

Macoma n. sp. aff. M. secta (Conrad, 1837) [pl. 8, fig. 

6]. A single specimen of an incomplete internal mold of 

a right valve, somewhat similar to Macoma secta, may 

represent an undescribed species. It is referred to the 

subgenus Rexithaerus because of the flange developed 

along the posterior dorsal margin. It differs from M. 

secta in being more elongate and in having a broadly 

truncate posterior margin. This taxon also differs from 

M. flagleri Etherington (1931, p. 85, pl. 10, figs. 3, 4) in 

having anteriorly, rather than centrally, located 

beaks. A specimen of M. flagleri is illustrated (pl. 8, fig. 

3) for comparison. A widening of the dorsal margin just 

posterior to the beaks indicates that this bivalve had 

an external ligament. 

Macoma n. sp. Moore (1963) [pl. 8, fig. 4]. An orbicular specimen that is almost as high as it is long appears 

to be the same as Moore's (1963, p. 81, pl. 29, figs. 10, 

11) Macoma n. sp. from near Newport, Oreg. This 

species was described as ttthin shelled, high in proportion to length, and perhaps almost circular in outline" 

(Moore, 1963, p. 81). Although recorded from the Astoria Formation (Moore, 1963), later mapping has 

shown that the seacliff localities 2-3 miles south of 

Newport are in the upper part of the Nye Mudstone 

(Snavely and others, 1969b, 1976). Data considered 

elsewhere in this report indicate a provincial early 

Miocene age for the Nye Mudstone. 

VENERIDAE 

Dosinia whitneyi (Gabb, 1866 [pl. 8, figs. 9, 10]. Small, 

orbicular specimens of Dosinia from localities M4414, 

M4683, M4684, NP160, and NP161 are identical with 

material from the Astoria Formation of Oregon identified as D. whitneyi (Gabb) by Moore (1963, p. 73, pl. 

24, figs. 1-10). These specimens are sculptured by fine 

concentric ribs and are of variable outline owing to 

deformation. The genus is of very rare occurrence in 

the Miocene of Oregon where it is known definitely 

only from dredgings of middle Miocene age at Coos Bay 

(Moore, 1963, p. 73). It also occurs in middle Miocene 

strata in southwestern Washington (Etherington, 

1931; Addicott in Wolfe and McKee, 1972, table 13) 

where it is also rare. The extremely small size of these 

specimens suggests that they may represent the northernmost limits of distribution of this warm-water 

genus during the early Miocene. Middle Miocene 

specimens from southwestern Washington 

(Etherington, 1931) and western Oregon (Moore, 1963) 

are of much smaller size than those from Oregon. The 

genus has been recorded from middle Miocene strata as 

far north as Kodiak Island, Alaska (lat 58° N.), but 

that occurrence may have been related to a western 

North Pacific lineage (Addicott, 1969). 

Katherinella angustifrons (Conrad, 1849) [pl. 8, figs. 7, 

8, 11-18]. Specimens from the Clallam are extremely 

variable in outline and in thickness. Nevertheless they 

can be separated into two forms. One has inflated 

valves that tend to be of quadrate shape; the other is 

only weakly inflated, tends to attain a larger adult 

size, is relatively thin shelled, and is usually, but not 

always, more orbicular in outline. Some of the thin 

orbicular forms attain a relatively large size (pl. 8, fig. 

18). The inflated form (pl. 8, figs. 15, 17) occurs in collections from locs. M4051, M4413, M4677, M4683, and 

NP163; the thin form (pl. 8, figs. 8, 12, 14, 16, 18) in 

M4049, M4050, M4414, M4684, and M5878. The inflated form is similar to the type and to specimens from 

the Nye Mudstone and the Astoria Formation of the 

northwest Oregon coast (Moore, 1963, pl. 24, figs. 

11-14, pl. 25, figs. 1-3, 5-15, pl. 26, figs. 4-6, 8). Specimens from localities NP89, NP161, and NP163 are not 

differentiated. Katherinella arnoldi ethringtoni (Tegland, 1929, p. 283, pl. 23, figs. 12-14), described from 

the Clallam Formation and also recorded from the 

upper member of the Twin River Formation (Durham, 

1944, p. 149), is a synonym of this species. 

. Securella ensifera (Dall, 1909) [pl. 9, figs. 1-3, 5, 6, 9, 

10, 13]. This species is one of the most abundant 

bivalves in the Clallam, however, most of the speci-
34 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

mens are devoid of shell material thereby making 

specific identification difficult. The external concentric 

sculpture has, nevertheless, been partially preserved 

on many of the internal molds. On a few specimens the 

sculpture is so well preserved that the fine radial 

sculpture underlying the concentric ribbing is exposed. 

The original surface sculpture of S. ensifera consisted 

of bladelike concentric ridges gently inclined toward 

the beaks. Almost all the species, however, have 

undergone abrasion or decortication that has exposed a 

layer characterized by fine radial ribbing. This species 

has been treated systematically by Moore (1963, p. 

7 5-76). Specimens described as Venus clallamensis and 

V. olympidea by Reagan (1909, p. 182-183, pl. 1, figs. 

12 and 13) are synonyms of this species. These are 

refigured in this report (pl. 9, figs. 3, 13). Securella, a 

genus that became extinct during the provincial 

Pliocene, is differentiated from the similar warmwater genus Chione by its deeply sunken ligament and 

V-shaped pallial sinus (Parker, 1949). A specimen 

from the basal part of the Clallam identified asS. alaskensis (Clark, 1932, p. 815, pl. 18, figs. 2, 3) by Parker 

(1949, p. 588) and Chione sp. (Durham, 1944, p. 146) 

presumably belongs to this species. Clark's (1932) 

species from the middle Miocene part of the Yakataga 

Formation, Alaska [not Poul Creek Formation as 

stated by Parker (1949)-see Kanno (1971, p. 87)], may 

be a synonym of this species. 

HIATELLIDAE 

Panopea ramonensis (Clark, 1925) [pl. 9, fig. 15]. This 

species has consistently longer valves in proportion to 

the height than does P. abrupta, which also occurs in 

the Clallam Formation. The beaks on this species vary 

from medial to a position anterior to the midline of the 

valves (Addicott, 1973, p. 37-38). The elongate form of 

Panopea ramonensis was previously recorded and figured from the Clallam by Weaver (1942, p. 264, pl. 59, 

fig. 11). That record was used by Hickman (1969, p. 60) 

and Addicott (1973) in defining a middle Oligocene to 

middle Miocene range for this species. This range must 

be revised to middle Oligocene to early Miocene in 

keeping with the revised provincial age of the Clallam 

(Addicott, 1975). 

Panopea abrupta (Conrad, 1849) [pl. 9, figs. 7, 8, 16]. 

This Panopea has more quadrate valves and occurs 

more commonly in the Clallam Formation than P. 

ramonensis. Panopea abrupta occurs in Miocene to 

Holocene formations along the Pacific coast and was 

recently recorded from the middle Oligocene of Oregon 

(Hickman, 1969, p. 65). Kanno's (1971, p. 93-94, pl. 11, 

fig. 3) Panopea n. sp.? from a locality in the upper part 

of the Poul Creek Formation, Gulf of Alaska, is very 

similar toP. abrupta, differing principally in having a 

strongly sloping anterior dorsal margin. 

THRACIIDAE 

Thracia trapezoides Conrad (1849) [pl. 9, figs. 4, 12]. 

This late Oligocene to Holocene species, originally described from the middle Miocene part of the Astoria 

Formation of Oregon, is fairly abundant in the Clallam 

Formation. It differs from the late Oligocene to early 

Miocene species T. schencki Tegland (1933, p. 112-113, 

pl. 6, figs. 6--11) and the Oligocene species T. condoni 

Dall (1909, p. 135-136, pl. 19, fig. 5) in having straight 

or slightly concave anterior and posterior segments 

along the ventral margin creating a lobate ventral 

margin. The ventral margin tends, therefore, to be 

more convex than in the-other species. A further difference is the generally larger size of the 0 ligocene 

species (Moore, 1963; Hickman, 1969). On most species 

of T. trapezoides, the umbonal ridge setting off the 

near-vertical posterior segment of the valve is much 

sharper than on older species. The valves of both T. 

schencki and T. condoni also tend to be longer in proportion to their height than those ofT. trapezoides. The 

lowest stratigraphic occurrence of this species is in the 

Echinophoria rex zone of northwestern Washington 

(Durham, 1944). 

Thracia c£. T. schencki Tegland (1933) [pl. 9, figs. 11, 

14]. Small elongate specimens from locality M4051 

near Slip Point seem to represent this species. Identification is doubtful because of limited material and poor 

preservation of the specimens. Thracia schencki Tegland has a much less convex dorsal margin and has 

more elongate valves than T. trapezoides. It also lacks 

the broad sinus between the posterior umbonal ridge 

and the midline of the valves that is characteristic ofT. 

trapezoides. 

CEPHALOPODS 

HERCOGLOSSIDAE 

Aturia angustata (Conrad, 1849). This species is 

doubtfully identified from a locality about 65 m above 

the base of the Clallam Formation (USGS loc. M5878). 

There is an undoubted record from the basal part of the 

Clallam Formation on the east flank of the anticline 

near Slip Point (Arnold and Hannibal, 1913, p. 588; 

Miller, 194 7, p. 87). Aturia angustata is definitely identified from near the top of the underlying upper 

member of the Twin River Formation close to the 

mouth of Pysht River (Schenck, 1931) and is of more 

common occurrence in collections from the type section 

of the lower Miocene Echinophoria apta zone near the 

mouths of the Twin Rivers several kilometres farther 

east (Arnold and Hannibal, 1913; Durham, 1944). 
FOSSIL LOCALITIES 35 

Occurrences of Aturia angustata in the California 

Miocene are very rare. The two records listed by 

Schenck (1931) are from strata northeast of Bakersfield, Calif., that are referable to the upper part of the 

~~vaqueros" Stage of Addicott (1972). The lowest of 

these records is from near the base of the Temblor 

Formation according to Schenck (1931). Records from 

Oregon (Moore, 1963) seem to be from the lower 

Miocene Nye Mudstone of the Newport Embayment or 

from the lower Miocene part of the Astoria Formation 

in more northern Miocene embayments. This taxon 

has not been recorded from the Astoria Formation in 

southwestern Washington. The fragmentary stratigraphic evidence points toward a pre-middle Miocene 

range for this species. Tentatively, it is considered to 

have become extinct during the later part of the provincial early Miocene. 

SCAPHOPODS 

DENTALIIDAE 

Dentalium pseudonyma Pilsbry and Sharp (1898) [pl. 

4, figs. 4, 8]. This radially ribbed species is of less common occurrence in the Clallam than the larger 

smooth-shelled D. schencki Moore. Further differences 

from D. schencki are the relatively thinner shell and 

straighter, less tapered form. 

Dentalium schencki Moore (1963) [pl. 5, fig. 11]. This 

relatively large smooth-shelled species, strongly tapered, is fairly abundant in the Clallam Formation. 

Both Dentalium schencki Moore and D. pseudonyma 

also occur in the middle Miocene part of the Astoria 

Formation of the Newport Embayment, Oreg. (Moore, 

1963). 

FOSSIL LOCALITIES IN THE 

CLALLAM FORMATION, 

CLALLAM COUNTY, 

NORTHWESTERN WASHINGTON 

US. Geological Survey localities, Menlo Park register 

M4049. Sea cliff and intertidal zone exposures near center of E% of 

sec. 32, T. 32 N., R. 11 W., 2,300 ft north, 1,300 ft west of 

SE cor. sec. 32, T. 32 N., R. 11 W., Pysht 15-minute 

quadrangle. From three 1-m-thick beds in an interval 

between 191 and 207m above the base of the formation. 

Collected by W. 0. Addicott, 1968, and Addicott and J. 

W. Miller, 1974. Same as UCMP A3962. 

M4050. Sea cliff and intertidal zone exposures 1,800 ft north, 700ft 

west of SE cor. sec. 32, T. 32 N., R. 11 W., Pysht 15-

minute quadrangle. From interval 52-59 m above the 

base of the formation. Collected by W. 0. Addicott, 1968. 

Same as UCMP A3693. 

M4051. Macoma arctata beds about 10m thick exposed in sea cliff 

almost 1 km east of Slip Point, 4,550 ft north, 700 ft west 

of SEcor. sec. 21, T. 32 N., R. 12 W., Pysht 7%-minute 

quadrangle. Collected by W. 0. Addicott, 1968. 

M4413. Intertidal exposure of sandstone with scattered Vertipecten 

and Epitonium about 1% km east of Slip Point, 3,000 ft 

north, 2,400 ft east ofSW cor. sec. 22, T. 32 N., R. 12 W., 

Pysht 15-minute quadrangle. Collected by W. 0. Addicott, 1970, and Addicott and J. W. Miller, 1974. 

M4414. Talus from seacliff exposure nearly 3 km east of Slip Point, 

600ft north, 2,100 ft east of SW cor. sec. 23, T. 32 N., R. 

12 W., Pysht 15-minute quadrangle. From an interval 

approximately 40-110 m above the base of the formation. Collected by W. 0. Addicott, 1970. 

M4675. Seacliff and intertidal zone exposures about two-thirds of a 

kilometre west of Pillar Point, 100ft north, 500ft east of 

NW cor. sec. 3, T. 31 N., R. 11 W., Pysht 15-minute 

quadrangle. Collected by W. 0. Addicott and J. E. Pearl, 

1971. 

M4"677. Intertidal zone exposures at north end of gravel beach at 

Slip Point, 4,900 ft north, 200 ft west of SE cor. Clallam 

Bay 15-minute quadrangle. Approximately 180m above 

the base of the formation. Collected by W. 0. Addicott, 

1971. 

M4678. Natural exposure on south side of logging road at top of 

steep sea cliff, 600 ft north, 800 ft west of SE cor. sec. 25, 

T. 32 N., R. 12 W., Pysht 15-lllinute quadrangle. Elevation 880 ft. Near the top of the formation. Collected by 

W. 0. Addicott, 1971, and Addicott and J. W. Miller, 

1974. 

M4679. Intertidal zone exposure about 4 km west of Pillar Point, 

4,400 ft north, 300 ft east of SW cor. sec. 32, T. 32 N., R. 

11 W., Pysht 15-minute quadrangle. Collected by W. 0. 

Addicott, 1971. 

M4680. Intertidal zone exposure about 150m southeast of M4679, 

4,100 ft north, 400 ft east of SW cor. sec. 32, T. 32 N., R. 

11 W., Pysht 15-minute quadrangle. Collected by W. 0. 

Addicott, 1971. 

M4681. Same as M4414. Collected by W. 0. Addicott, 1971. 

M4683. Intertidal zone exposure about 1% k west of Pillar Point, 

500ft north, 3,700 ft east of SW cor. sec. 33, T. 32 N., R. 

11 W., Pysht 15-minute quadrangle. Collected by W. 0. 

Addicott and J. E. Pearl, 1971. 

M4684. Intertidal zone exposure approximately two-thirds of a 

kilometre west of Pillar Point, 250 ft north, 400 ft east of 

NW cor. sec. 3, T. 31 N., R. 11 W., Pysht 15-minute 

quadrangle. Collected by W. 0. Addicott and J. E. Pearl, 

1971. 

M5878. Same as M4049. Collected by W. 0. Addicott, 1973. 

M5879. Same as M4050. Collected by W. 0. Addicott, 1973. 

M5885. Intertidal zone exposure at base of sandy beach approximately 3 k west of Pillar Point, 2,800 ft north, 3,300 ft 

east of SW cor. sec. 32, T. 32 N., R. 11 W., Pysht 15-

minute quadrangle. Collected by W. 0. Addicott and J. 

E. Pearl, 1973. 

M5886. Prominent point about one-half a kilometre east of Slip 

Point, 5,100 ft north, 1,400 ft west ofSE cor. sec. 21, T. 32 

N., R. 12 W., Pysht 15-minute quadrangle. Collected by 

W. 0. Addicott, 1973. 

M6029. Intertidal exposure of massive, Vertipecten-bearing 

sandstone at base of gravel beach at Slip Point Lighthouse compound, 300 ft west, 4,250 ft north of SE cor. of 

Clallam Bay 15-minute quadrangle. Approximately 130 

m above the base of the formation. Collected by W. 0. 

Addicott, 1973. 

M6373. Intertidal zone exposure of 1-m-thick fossil bed 27m N. 26° 

W. ofM4049 and 12m stratigraphically above M4049, in 

N%N%SEI,4 sec. 32, T. 32 N., R. 12 W., Pysht 15-minute 

quadrangle. Approximately 230m above the base of the 
36 MOLLUSCAN PALEONTOLOGY, LOWER MIOCENE CLALLAM FORMATION, NORTHWESTERN WASHINGTON 

formation. Collected by W. 0. Addicott and J. W. Miller, 

1974. 

M6375. Large blocks of silty sandstone at base of cliff about 100m 

west of giant talus pile 550 ft north, 1,850 ft east of SW 

cor. sec. 23, T. 32 N., R. 12 W., Pysht 15-minute quadrangle. Lowest 20--40 m of the formation. Collected by W. 

0. Addicott and J. W. Miller, 1974. 

Stanford University localities 

[These descriptions are from the Stanford University locality register. Published 

descriptions in Arnold and Hannibal 11913, p. 5891 are different in some respects] 

NP89. Oligocene-Miocene, Monterey basal sandstone, seacliffs 

eastward from Slip Point for half a mile, Clallam Bay, 

Wash. Collected by A. B. Reagan and Harold Hannibal, 

1911, 1912. USGS localities M4051 and M5886 are from 

the same area. 

NP160. Monterey sandstone, seacliffs at Pillar Point, straits east of 

Clallam Bay, Wash. Collected by Harold Hannibal, 

1912. USGS localities M4675, M4683, and M4684 are 

from the same area. 

NP161. Monterey shale and sandstone, seacliffs 11/2 miles west of 

Pillar Point, Clallam Bay, Wash. Collected by Harold 

Hannibal, 1912. USGS localities M4049 and M4050 are 

from the same area; the assemblage from M4049 most 

closely resembles that of NP161. 

NP162. Monterey carbonaceous sandstone, seacliffs at coal mine, 

straits east of Clallam Bay, Wash. Collected by Harold 

Hannibal, 1912. Probably stratigraphically higher than 

M4678 which is from the same area. 

NP163. Oligocene-Miocene, Monterey shaly sandstone east of Clallam Bay, Wash. Collected by Harold Hannibal, 1912. 

Probably same locality as M4681. 

Washington University (Seattle) localities 

UW270. Cliff, south shore of Strait of Juan de Fuca, Clallam 

County, sec. 23, T. 31 N., R. 12 W. (Weaver, 1942). 

UW 490. Very shaly sandstone in cliff, beach section 11,000 ft 

southeast of Slip Point and 13,000 ft due east of the town 

of Clallam Bay, Clallam County, NE14SE14 sec. 22, T. 32 

N., R. 12 W. (Weaver, 1942). 

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Washington: California Univ. Pubs., Dept. Geol. Sci. Bull., v. 23, 

no. 3, p. 81-174, pls. 2--15. 

Turner, D. L., 1970, Potassium-argon dating of Pacific coast Miocene 

foraminiferal stages, in Bandy, 0. L., ed., Radiometric dating 

and paleontologic zonation: Geol. Soc. America Spec. Paper 124, 

p. 91-129. 

Valentine, J. W., 1966, Numerical analysis of marine molluscan 

ranges on the extratropical northeastern Pacific shelf: Limnology and Oceanography, v. 11, no. 2, p. 198-211. 

Van Winkle, Katherine E., 1918, Paleontology of the Oligocene of 

the Chehalis Valley, Washington: Washington Univ. Pub. Geology, v. 1, no. 2, p. 69-97. 

Wagner, H. C., 1967, Preliminary geologic map of the Raymond 

quadrangle, Pacific Co., Washington: U.S. Geol. Survey open-file 

report, scale, 1:62,500. 

Weaver, C. E., 1912, A preliminary report on the Tertiary paleontology of western Washington: Washington Geol. Survey Bull. 15, 

80 p., 15 pls. 

---1916a, The Tertiary formations of western Washington: 

Washington Geol. Survey Bull. 13, 327 p. 

---1916b, Tertiary faunal horizons of western Washington: 

Washington Univ. Pub. Geology, v. 1, no. 1, p. 1-67, pls. 1-5. 
REFERENCES CITED 39 

---1937, Tertiary stratigraphy of western Washington and 

northwestern Oregon: Washington Univ. Pub. Geology, v. 4, 

266p. 

---1942, Paleontology of the marine Tertiary formations of Oregon and Washington: Washington Univ. [Seattle] Pubs. Geology, 

v. 5, pts. 1-3, 789 p., 104 pls. 

Weaver, C. E., Chm., and others (20), 1944, Correlation ofthe marine 

Cenozoic formations of western North America: Geol. Soc. 

America Bull., v. 55, no. 5, p. 569-598. 

Wiedey, L. W., 1928, Notes on the Vaqueros and Temblor formations 

of the California Miocene with descriptions of a new species: San 

Diego Soc. Nat. History Trans., v. 5, no. 10, p. 95--182, pls. 9-21. 

Wolfe, E. W., and McKee, E. H., 1972, Sedimentary and igneous 

rocks of the Grays River quadrangle, Washington: U.S. Geol. 

Survey Bull. 1335, 70 p. 

Zinsmeister, W. J., 1974, A new interpretat~on of thermally anomalous molluscan assemblages of the California Pleistocene: Jour. 

Paleontology, v. 48, no. 1, p. 84-94. 

Page 

A 

abrupta, Panope __ ------------------------------- 4 

Panopea ____________________ 4, 6, 14, 18, 34, pl. 9 

Acila __ __ _ _ __ _ _ ___ _ __ __ _ _ _ _ __ _ _ _ _ __ ___ _ __ ___ _ __ 27 

conradi ------------------------ 4, 5, 14, 27, pl. 3 

gettysburgensis ------------------------------ 17 

(Acila) castrensis, Nucula ________________________ 4 

conradi, Nucula ------------------------------ 4 

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

acutilineata, Lucinoma ______ 4, 5, 14, 18, 19, 30, pl. 5 

acutilineatus, Phacoides __________________________ 4 

aequisulcatum, Semicassis ____ ____________________ 22 

Age __ __ __ _ _ __ __ ___ _ __ __ _ _ _ _ __ _ _ __ __ _ _ _ _ __ __ _ _ __ 12 

Alaska __________________________________________ 24 

Alaska Peninsula, Miocene assemblages ____________ 2 

alaskensis, Securella ---------------------------- 34 

albaria, Macoma __________________ 6, 14, 15, 32, pl. 7 

Spisula ---------------- 4, 5, 14, 15,31, pis. 6, 7 

goodspeedi, Spisula ________ 5, 10, 14, 31, pis. 6, 7 

alta, Metis ________________________________________ 4 

Amauropsis oregonensis __________________________ 4 

Anadara ------------------------------------ 19, 28 

devincta ---------------------- 5, 12, 14, 28, pl. 5 

lakei ---------------------- 5, 11, 14, 15,28, pl. 5 

s.s ------------------------------------------ 20 

submontereyana __________________ 28 

Ancistrolepis clarki ------------------------------ 23 

clarki teglandae ____________________________ 23 

rearensis __________ 5, 10, 14, 15, 16, 17,23, pl. 3 

anglonana, Molopophorus ________________________ 24 

angustata, Aturin. __________________________ 6, 14,34 

angustifrons, Katherinella ______ 4, 6, 14, 15, 33, pl. 8 

Venus, <Chione) ------------------------------ 4 

annulata, Lucinoma -------------------------- 18, 19 

Antigona olympidea ______________________________ 4 

antiselli, Thesbia -------------------------------- 26 

Xenuroturris __________________ 5, 15, 26, pis. 2, 3 

apta, Echinophoria ------------------------------ 23 

Liracassis _____________ _____ ______ __________ 17 

Archarax __ ______________________________________ 18 

dalli -------------- 5, 10, 11, 13, 14, 16, 28, pl. 3 

ventricosa __________________________________ 28 

willapaensis -------------------------------- 28 Arcidae ________________________________________ 28 

arctata, Macoma ________________ 3, 4, 6, 14, 32, pl. 7 

Tellina ------------------------------------ 3, 4 

Juana, Tellina ---------------------- 4, 32, pl. 7 

Armentrout, J. M., cited ________________________ 16 

Arnold, Ralph, cited ____________________________ 6, 7 

arnoldi, Macoma -------------------------- 32, pl. 7 

ethringtoni, Katherinella ____________________ 33 

astori, Macoma ________________ 6, 10, 14, 19, 32, pl. 7 

Astoria, Oreg -------------------------------- 15, 18 

Astoria Formation __________________________ 26, 33 

age --------------------- __________________ 16 

benthonic foraminifera ______________________ 16 

contact_ _____________________________________ 15 

fauna, Newportian ______________________ 17, 21 

middle Miocene ______________________________ 18 

molluscan fauna __________________ 12, 16, 17 

Miocene fauna ____________________________ 3, 16 

Newport Embayment, Oreg __________________ 28 

Oregon ________________ 3, 10, 12, 16, 17, 20, 21, 

25, 26, 27, 28, 29, 31, 33, 34, 35 

southwestern Washington ______________ 3, 10, 17, 

23, 24, 26, 27, 28, 29, 31, 35 

type area ---------------------------------- 18 

INDEX 

[Italic page numbers indicate major references] 

Page 

Aturin. _______ ---------------------------------- 17 

angustata 6, 14,34 

B 

Baja California, Mexico __________________________ 20 

Bakersfield, Calif-------------------------------- 35 

Barker's Ranch fauna ____________________________ 13 

Bathymetry ____________________________________ 18 

Biostratigraphy __________________________________ 6 

birchi, Cancellaria ____________________ 5, 15, 25, pl. 2 

bisecta, Conchocele ------------------------------ 30 

Blakeley Formation, Washington ______________ 25, 30 

Blakeley Stage __________________ 6, 13, 16, 18, 29, 31 

British Columbia_______ _ ________________ 13 

brota, Macoma ---------------------------------- 19 

Bruclarkia _____________________________________ 23 

oregonensis -------------------- 4, 5, 14, 23, pl. 2 

yaquinana ____________________ 5, 14, 15, 23, pl. 2 

Buccinum clallamensis ___________________________ 4 

bulbosus, Teredo ___ ------------------------------ 4 

c 

California, Coast Ranges __ _ ______________ 12, 18 

formaminiferal correlation __________________ 16 

middle Miocene strata ____________________ 12, 20 

Temblor Stage ---------------------------------- 12 

Vaqueros Stage-------------------------- 12, 13 

calkinsi, Nuculana ________________ 5, 14, 15, 27, pl. 3 

Calyptraea sp ------------------------------------ 4 

Calyptraeidae __________________________________ 21 

Canada, western, provincial molluscan stages ______ 4 

Cancellaria______________________________________ 19 

birchi_______ _ ________ 5, 15, 25, pl. 2 

oregonensis __________________ 5, 15, 25, 26, pl. 2 

siletzensis ____________________ 5, 11, 15, 25, pl. 2 

simplex ______________________ 5, 12, 15,25, pl. 2 

wynoocheensis _______________ 5, 12, 15, 26, pl. 2 

(Euclia) ------------------------------------ 20 

Cancellariidae ___ _ ___________________ 25 

Cape Yakataga, Alaska ____ ______________________ 17 

Cardiidae ______________________________________ 30 

Carditidae _____ _ -------------- 30 

Carnivore, marine---------------------------- ___ 4 Cassididae ______________________________________ 22 

castor, Cyclocardia ------------------------------ 30 

castrensis, Nucula (Acila) ________________________ 4 

catilliformis, Spisula ---------------------------- 31 

centiquadrata, Semicassis ______________________ 23 

Cephalopods ------------------------------ 6, 14,34 

Cetacean bones _ -------------------------------- 4 

chehalisensis, Nuculana __________ 5, 12, 14, 27, pl. 3 

Chione ____ ------------------------------------ 34 

sec uris _ _ __ _ _ _ _ __ __ _ _ _ _ __ _ _ _ _ __ __ _ _ _ _ _ _ _ _ _ _ _ _ 4 

sp _________________________________________ 34 

(Chione) angustifrons, Venus _______________________ 4 

clallamensis, Venus __________________________ 4 

olympidea, Venus ---------------------------- 4 

(Chlamys) fucanus, Pecten ________________________ 4 

wattsi morani, Pecten _____________ 4 

Clallam Bay __________________________ 1, 3, 6, 21, 30 

Clallam coal mine _____________________________ 19 

Clallam County, Washington ____________________ 35 

Washington, fossil localities __________________ 35 

Clallam fauna, late early Miocene _______________ 20 

Clallam Formation __________________________ 1, 6, 24 

age _____________________________________ 12, 20 

Page 

Clallam Formation-Continued 

benthonic foraminifera ____________________ 4, 12 

contact-------------------------- 2, 6, 7, 8, 9, 16 

correlation ________________________ 2, 6, 7, 8, 12 

depositional cycle ________________________ 1, 11 

depositional environment ________________ 18, 20 

exposures---------------------------------- 1, 8 

fauna ______________________ 3, 4, 5, 6, 16, 17,20 

Pillarian ________________________________ 17 

faunal assemblages ___________ 10, 11, 12, 18, 19 

faunal hiatus __________________________ 9, 10, 16 

fossil localities ______________________ 8, 9, 11,35 

fossils________________________________________ 6 

lithology ---------------------------------- 1, 7 

living species ________________________________ 18 

marine carnivore ---------------------------- 4 

marine mollusks __________ 1, 2, 3, 10, 15, 17, 18 

microfauna! boundary------------------------ 16 

Miocene assemblages ________________ 2, 7, 12, 19 

Miocene boundary---------------------------- 2 

molluscan fauna ---------------------------- 20 

nomenclatorial history---------------------- 6, 7 

Oligocene-Miocene boundary __________________ 2 

provincial chronostratigraphy ________________ 12 

restricted species ________________________ 11, 12 

stratigraphy ------------------------------ 7, 8 

thickness---------------------------------- 1, 7 

type locality ------------------------------ 3, 7 

type section -------------------------------- 18 

unconformity ________________________________ 16 

Washington __ ------------------------------ 21 

clallamense, Epitonium ________ 5, 14, 16, 17,21, pl. 1 

clallamensis, Buccinum __________________________ 4 

Pisania __________ ---------------------------- 4 

Tellina ------------------------------ 4, 32, pl. 7 

Trophosycon ______________ 5, 14, 15, 23, pis. 1, 2 

Venus ------------------------ ________ 34, pl. 9 

(Chione)---------------------------------- 4 

clarki, Ancistrolepis_ __ ----------------------- ____ 23 

Natica __________________________ 5, 14, 22, pl. 1 

Prisco{ usus _________________ ----------------- 24 

teglandae, Ancistrolepis ______________________ 23 

Clinocardium __________________________________ 30 

nuttalli ________________ 5, 11, 14, 19, 30, pis. 5, 6 

sookensis ____________________________________ 31 

yakatagense -------------------------------- 31 

n. sp ------------------------------ 30, pis. 5, 6 

Coast Ranges, California __________________ 12, 18, 23 

columbiana, Lucinoma -------------------------- 30 

Conchocele bisecta ------------------------------ 30 

disjuncta __________________ 5, 11, 14, 18, 30, pl. 6 

condonana, Megasurcula ________________________ 27 

condoni, Thracin. -------------------------------- 34 

conradi, Acila ______________________ 4, 5, 14, 27, pl. 3 

Nucula !AcilaL _______________________________ 4 

Solen---------------------------- 6, 14,31, pl. 6 

Coos Bay ____________ ---------------------------- 33 

Correlation _____________________________________ 12 

foraminiferal ___ _ _______________ 12, 13, 16 

molluscan ---------'--------------------- 12, 16 

corrugata, Musashia ___________________________ 25 

Crenella porterensis ------------------------------ 29 

Crepidula ____ ________________________________ 21, 22 

praerupta ________________ 5, 14, 21, 22, pis. 1, 2 

princeps ______________________ 5, 10, 14,21, pl. 1 

rostralis ________________________ 5, 14, 22, pl. 2 

sookensis ____________________________________ 22 

sp ---------------------------------- 5, 22, pl. 1 

41 
42 

Page 

Crescent Formation ___________________________ 3, 6 

Cuyama Valley area, California __________________ 23 

Cyclinella sp ------------------------------------ 4 

Cyclocardia castor ------------------------------ 30 

subtenta _________________ 5, 14, 15, 30, pis. 5, 6 

yakatagensis ______________________________ 30 

D 

dalli, Archara.x ________ 5, 10, 11, 13, 14, 16, 28, pl. 3 

Dentaliidae ____________________________________ 35 

Dentalium pseudonyma ____________ 4, 5, 15, 35, pl. 4 

schencki ------------------------ 5, 15, 35, pl. 5 

substriatum --------------------- ____________ 4 

devincta, Anadara ________________ 5, 12, 14,28, pl. 5 

Dibblee, T. W., Jr., cited ________________________ 27 

disjuncta, Conchocele ______ 5, 11, 14, 18, 30, pl. 6 

Dosinia ________________________________ 19, 20, 33 

whitneyi ______________________ 6, 14, 33, pl. 8 

E 

East Clallam ------------------------------------ 3 

East Twin River _ ------------------------------ 30 

Echinophoria apta ------------------------------ 23 

apta zone __ ----------------- 6, 7, 18, 23, 32, 34 

rex zone -------------------------------- 25,34 

elmana, Nuculana ____________________ 5, 14, 27, pl. 3 

emacerata, Tellina ______________ 4, 6, 14, 15,31, pl. 7 

ensifera, Securella ______________ 4, 6, 14, 15, 33, pl. 9 

Eocene-Miocene depositional cycle ________________ 1 

eparchis, Nuculana ________ _____________________ 27 

Epitoniidae ____________________________________ 21 

Epitonium clallamense ________ 5, 14, 16, 17,21, pl. 1 

equilateralis, Spisula ---------------------------- 31 

ethringtoni, Katherinella arnoldi __________________ 33 

Euclia ___ _ ____ _____ _ ____ ____ _ _ ______ ___ _________ 19 

(Euclia ), Cancellaria -------------------- 20 

F 

Felaniella 

parilis _________________________________ 14, 30 

sp ---------------------------------- 5, 30, pl. 5 Ficidae ________________________________________ 23 

Ficus---------------------------------------- 19, 20 

modesta __________________ _______ 5, 14, 23, pl. 1 

filosa, Trochita ----------------------- __________ 21 

flagleri, Macoma _________________________ 33, pl. 8 

Foraminifera, benthonic ____ 2, 4, 12, 13, 16, 18, 20, 27 

Jewett Sand -------------------------------- 13 Luisian ___________________________________ 27 

Relizian ____________________________________ 27 

Saucesian ---------------------------- 13, 16, 27 

Fossil, bathymetric index ______________________ 19 

Fossil localities, Clallam County, Washington ____ 35 

Clallam Formation _________________________ 35 

Stanford University __________________________ 36 

stratigraphic sequence ______________________ 8, 9 

U.S.G.S., Menlo Park register ________ 8, 9, 11,35 

Washington University (Seattle)----------··--- 36 

Fossil species, Oregon ___________________________ 10 

Washington _____________________ 10 

Fossils, Astoria, Oreg ____________________________ 15 

index species_____ ________________________ 13 

preservation __________ 6, 16 

restricted species --:---------------------- 10, 11 

zonal index species _________________________ 10 

Freeman Silt ___________________________________ 27 

fucanus, Pecten <Chlamys) _______________________ 4 

Vertipecten _____________ 4, 5, 10, 13, 14, 15, 16, 

17, 27, 29, pl. 4 

Fusinidae _____ _ _____________________ 24 

Fusinus hannibali 

G 

Gastropod fauna_______ _ ________________ 3 

Gastropods _______________ 4, 5, 6, 14, 15, 16, 20,21 

generosa, Panopea ________ _ ____________ 4 

INDEX 

Page 

geniculus, Prisco( usus __________ 5, 11, 15, 16, 24, pl. 2 

gettysburgensis, Acila ---------------------------- 17 

gibbosus, Saxidomus _____________________________ 4 

gibbsana, Mactra _______________________ 4, 31, pl. 7 

Glycymerididae _________________________________ 28 

Glycymeris ______________________________________ 28 

sp -------------------------------- 4, 5, 28, pl. 5 

goodspeedi, Spisula albaria ____ 5, 10, 14,31, pis. 6, 7 

Gower, H. D., cited---------------------------- 9, 24 

goweri, Priscofusus ____________ 4, 15, 20, 24, 25, pl. 2 

graciosana, Ophiodermella ______________________ 26 

Grays Harbor basin, Washington ________________ 27 

Grays River quadrangle, southwestern 

Washington ----------------------------- 18,26 

Gulf of Alaska ________________________ 25, 30, 31, 32 

Miocene fauna _____________ 2, 17,21 

H 

Hannibal, Harold, cited __________________________ 20 

hannibali, Fusinus _____________________________ 24 

Lucinoma ---------------------------------- 30 

Priscofusus ------------------------------ 24, 25 

Spisula ---------------- 5, 10, 13, 14, 16,31, pl. 6 

Hercoglossidae __________________________________ 34 

Hiatellidae ______________________________________ 34 

Hoh Formation---------------------------------- 27 

Hoh rock assemblage ________________________ 18, 30 

Hokkaido, Japan -------------------------------- 28 

Hoko River -------------------------------------- 7 

Honshu Island, Japan ___________________________ 32 

iani, Semicassis _______________________________ 22 

impressa, Yoldia __________________________________ 4 

indurata, Musashia ______________ 5, 11, 15, 25, pl. 3 

inornata, Trochita -------------------------------- 4 

Introduction _______ _ _________________ I, 6 

J 

jamesae, Neverita -------------------- 5, 14,22, pl. 1 

Japan _____________________________________ 18,23 

Jewett Sand ________________________ 13, 21. 26, 30 

juana, Tel/ina arctata ___________________ 4, 32, pl. 7 

Juanian Stage ______ _ _____ 6, 16, 17, 18 

K 

Kamchatka __ _ ---------- 28, 29 

Russia ______________________________________ 32 

Katherinella angustifrons ________ 4, 6, 14, 15, 33, pl. 8 

arnoldi ethringtoni __________________________ 33 

Keasey Formation ------------------------------ 28 

kernianum, Trophosycon 23 

Kodiak Island, Alaska __________________________ 33 

Kuluven Suite ______ _ 

L 

lakei, Anadara ________________ 5, 11, 14, 15, 28, pl. 5 

Last Creek ____ --------------------------------- 7 

Lincoln Creek Formation ______________________ 32 

Lincoln Stage _ -------------------------------- 29 

lipara, Macoma _______ _ 

Liracassis apta __________________________________ 17 

Lucinidae ________________________ 30 

Lucinoma ______________________________________ 18 

acutilineata 4, 5, 14, 18, 19, 30, pl. 5 

annulata ______________________________ 18, 19 

columbiana -------------------------------- 30 

hannibali _ -------------------------------- 30 

(Lunatia) olympidii, Polynices 4 

Lyre Formation _____ _ 7 

McCormick, Lavon, cited 

Macoma _ 

M 

20 

------------------ 32, 33 

Page 

Macoma-Continued 

albaria ______________________ 6, 14, 15, 32, pl. 7 

arctata ______________________ 3, 4, 6, 14, 32, pl. 7 

arnoldi -------------------------------- 32, pl. 7 

astori ____________________ 6, 10, 14, 19, 32, pl. 7 

brota -------------------------------------- 19 

flagleri -------------------------------- 33, pl. 8 

lipara ------------------ ____________________ 33 

nasuta ---------------------------------- 32, 33 

secta ______________ 6, 12, 14, 15, 19, 20, 33, pl. 8 

sookensis ____________________ 6, 14, 33, pis. 7, 8 

twinensis ______ 6, 10, 11, 13, 14, 16,32, pis. 6, 7 

n. sp __________________ 6, 14, 15, 16, 20, 33, pl. 8 

Mactra gibbsana ------------------------ 4, 31, pl. 7 

Mactridae ________________ ---------------------- 31 

Mactrids ________________________________________ 19 

Marcia oregonensis ------------------------------ 4 

Matlockian Stage __________________ 6, 13, 16, 18, 29 

matthewi, Molopophorus ______________________ 16, 24 

Megasurcula __________________ ------------------ 27 

condonana ---------------------------------- 27 

wynoocheensis ________________ 5, 15, 19, 27, pl. 3 

spp ---------------------------------------- 19 Metis alta ____________________________________ - ___ 4 

Mexico__________________________________________ 19 

middendorffi, Mytilus ------------------------ 13,29 

Miocene, index species -------------------------- 27 

Miocene assemblages ---------------------------- 2 

Miocene boundary-------------------------------- 2 

mollusks ------------------------------------ 2 

Miocene fauna, Astoria Formation ________________ 3 

Gulf of Alaska_______________________________ 3 

modesta, Ficus ______________________ 5, 14, 23, pl. 1 

Modiolus ______________________________________ -- 28 

restorationensis ________ 5, 11, 14, 15, 20, 28, pl. 5 

n. sp ------------------------------ 20, 28, pl. 5 

Molluscan fauna ____________ 3, 4, 7, 9, 10, 12, 18, 20 

Molluscan paleontology-------------------------- 20 

Molluscan province, late early Miocene __________ 2, 3 

Mollusks, depth ranges __________________________ 18 

index species-------------------------------- 13 

living genera ________________________________ 19 

stratigraphic distribution __________ 10, 11, 13, 15 

Molopophorus __________________________________ 24 

anglonana _________________________________ 24 

matthewi -------------------------------- 16, 24 

newcombei ____________ 5, 14, 15, 16, 20, 24, pl. 2 

n. sp ______________________________ 20, 24, pl. 2 

Monterey Formation------------------------------ 6 

Montesano Formation, Weaver ------------------ 31 

Moore, E. J., cited ____________________ 20, 21, 25, 27 

Moore, R. C., cited ------------------------------ 20 

morani, Pecten (Chlamys) wattsi ------------------ 4 

muirensis, Ophiodermella ------------------------ 26 

Muricidae ______________________________________ 23 

Musashia ______________________________________ 18 

corrugata _________________________________ 25 

indurata ______________________ 5, 11, 15,25, pl. 3 

weat•eri _____________________ _ _______ 17 

Mytilidae ______________________________________ 28 

Mytilids ______________________________________ - --- 6 

Mytilus -------------------------------------- 3, 19 

middendorf{i ---------------------------- 13, 29 

ochotensis ------------------------------ 28, 29 

tichanouitchi ______ 5, 13, 14, 16, 19, 20,28, pl. 5 

n. sp _____________________ 15, 20, 28, pl. 5 

N 

nasuta, Macoma__________________ _ _______ 32,33 

Natica ___________________________ _ __________ 19 

clarki_____________ 5, 14, 22, pl. 1 

uokesi_ ____________ ______________ 5, 14, 22, pl. 1 

Naticidae _ ------------------------------------ 22 

Neptuneidae ____ ------------------------------- 23 

Neverita ________ ____________ _ _________________ 19 

jamesae __________________________ 5, 14, 22, pl. 1 

<Neverita) saxea, Polynices ________________________ 4 

newcombei, Molopophorus __ 5, 14, 15, 16, 20, 24, pl. 2 

Newell, N.D., cited ______________________________ 20 
Page 

Newport, Oregon ____________________________ 24, 33 

Newport Embayment, Oreg __ 13, 15, 16, 18, 21, 28, 35 

Newportian Stage ------------------------------ 17 

Nucula <Acilal castrensis __________________________ 4 

(Acila) conradi ------------------------------ 4 

Nuculana calkinsi ________________ 5, 14, 15, 27, pl. 3 

chehalisensis __________________ 5, 12, 14, 27, pl. 3 

elmana -------------------------- 5, 14,27, pl. 3 

eparchis ------------------------------------ 27 

Nuculanidae ____________________________________ 27 

Nuculidae ______________________________________ 27 

nuttalli, Clinocardium ______ 5, 11, 14, 19, 30, pis. 5, 6 

Nye Mudstone ______________ 11, 15, 16, 25, 27, 28, 33 

age ______________________________________ 16, 17 

benthonic foraminifera ______________________ 16 

contact_ _____________________________________ 15 

fauna ---------------------------- 16, 18, 21,24 

Oregon _________________________________ 30,35 

0 

ochotensis, Mytilus ________________ 28, 29 

Oligocene-Miocene boundary, foraminifera __________ 2 

Olympic Mountains, Wash ______________________ 18 

Olympic Peninsula, Washington ____________ 1, 27, 30 

olympicensis, Ophiodermella ____ 4, 5, 15, 20,26, pl. 3 

olympidea, Antigona ------------------------------ 4 

Venus -------------------------------- 34, pl. 9 

(Chione) _________________________________ 4 

olympidii, Polynices (Lunatia) -------------------- 4 

Ophiodermella __________________________________ 26 

graciosana __________________________________ 26 

muirensis ---------------------------------- 26 

olympicensis ________________ 4, 5, 15, 20,26, pl. 3 

workensis ---------------------------------- 26 n. sp ________________________________________ 26 

Oregon, middle Miocene strata __________________ 12 

molluscan province ________________________ 2, 3 

Nye Mudstone ------------------------------ 16 

zonal index species __________________________ 10 

oregonensis, Amauropsis __________________________ 4 

Bruclarkia ____________________ 4, 5, 14,23, pl. 2 

Cancellaria __________________ 5, 15,25, 26, pl. 2 

Marcia ______________________________________ 4 

Tellina -------------------------------------- 4 

Turritella ------------------------ 5, 14,21, pl. 1 

(0udardia) sp., Tellina ______________________ 32 

p 

Pacific coast----------------- ________ 19, 21, 23,32 

Pacific Northwest States, provincial 

molluscan stages ____________________________ 4 

Page Mill Basalt _______________________ 27 

Paleoclimate ___________________________________ 19 

Paleoecology _______________________ _ ----------- 18 

Panamic molluscan province __________________ 23 

Panope abrupta ---------------------------------- 4 

Panopea ------------------------------------ 18, 34 

abrupta -------------------- 4, 6, 14, 18, 34, pl. 9 generosa ___________________________________ 4 

ramonensis _____________________ 6, 14, 34, pl. 9 

n. sp _______________________________________ 34 

parilis, Felaniella __________________________ 14, 30 

Patinopecten ___________________________________ 15 

propatulus ------------------------- 13, 16, 29 

(Patinopecten) propatulus, Pecten __ _________ 4 

patulus, Petunculus __________________________ 4 

Pecten (Chlamys)fucanus ________________________ 4 

!Chlamysl wattsi morani _____________________ 4 

!Patinopecten) propatulus ______________________ 4 

Pectinidae _____________________________________ 29 

Pectinids ---------------------------------- 6, 10, 13 

Pelecypod fauna _________________________________ 3 

Pelecypods ________________ 4, 5, 10, 14, 15, 16, 20,27 

Petunculus patulus _______ ________________________ 4 

Phacoides acutilineatus _____ ______________________ 4 

Phalium _ ----------------------------- ________ 22 

Pillar Point ______ 3, 7, 8, 9, 12, 19, 21, 24, 25, 27, 28 

Pillarian Stage ____________________ 6, 12, 16, 17,18 

INDEX 

Page 

Pillarian Stage-Continued 

type section ___________________ 2, 18 

Pisa~ia clallamensis ------------------------------ 4 

Polinices saxea ---------------------------------- 22 

victorianus ---------------------- 5, 14, 22, pl. 1 

Polynices (Lunatia) olympidii ______________________ 4 

<Neuerita) saxea ______________________________ 4 

Porter Bluffs, Washington ________________________ 29 

porterensis. Crenella ---------------------------- 29 

Solamen _____________________________ 29, pl. 4 

Poul Creek ____ --------------------------------- 17 

Poul Creek Formation, 

Gulf of Alaska ______________ 21, 23, 30, 31, 32, 34 

molluscan assemblages ______________________ 17 

praerupta, Crepidula __________ 5, 14,21, 22, pis. 1, 2 

Previous faunal studies -------------------------- 3 

princeps, Crepidula ________________ 5, 10, 14,21, pl. 1 

Priscofusus ---------------------------------- 24, 25 

clarki __ __ _ _ __ _ _ __ __ _ _ _ _ __ __ _ _ _ _ __ __ _ _ _ _ __ _ _ 24 

geniculus ---------------- 5, 11, 15, 16, 24, pl. 2 

goweri ____________________ 4, 15, 20,24, 25, pl. 2 

hannibali -------------------------------- 24, 25 

slipensis __________________ 4, 5, 15, 20, 24, pl. 2 

stewarti _________ 5, 10, 11, 15, 16, 24, 25, pl. 2 

n. sp ------------------------------------ 24,25 

propatulus, Patinopecten __________________ 13, 16, 29 

Pecten (Patinopecten)_ _________________________ 4 

Provincial chronostratigraphy ____________________ 12 

Provincial molluscan stages ______________________ 4 

pseudonyma, Dentalium ____________ 4, 5, 15, 35, pl. 4 

Pysht River ______________________________ 1, 7, 34 

pyshtensis, Semicassis ____ 4, 5, 11, 14, 15, 20, 22, pl. 1 

Q 

quadrata, Venericardia subtenta _________________ 30 

R 

ramonensis, Panopea ________ _________ 6, 14, 34, pl. 9 

Raymond quadrangle, Washington ________________ 27 

Reagan, A. B., cited __________________________ 3, 20 

reagani, Yoldia ---------------------------------- 4 

rearensis, Ancistrolepis __ 5, 10, 14, 15, 16, 17, 23, pl. 3 

Rectiplanes__ __ _ _ ___________________________ 26 

sp ---------------------------------- 5, 26, pl. 2 

Reed Creek -------------------------------------- 7 

References cited _______________________________ 36 

Relizian Stage ---------------------------------- 16 

restorationensis, Modiolus __ 5, 11, 14, 15, 20, 28, pl. 5 

Rexithaerus ________________________ 33 

rostralis, Crepidula ____________ 5, 14,22, pl. 2 

s 

San Francisco Bay region, California _____________ 27 

San Joaquin basin, Calif ________ 13, 23, 25, 26, 29 

San Pablo Group-------------------------------- 31 

Saucesian Stage ----------------------------- 4, 16 

foraminiferal assemblages ____________________ 27 

saxea, Polinices --------------------------------- 22 

Polynices (N~verital __________________________ 4 

Saxidomus gibbosus ------------------------------ 4 

Scaphopods ---------------------------- 4, 5, 15,35 

Schenck, H. G., cited ____________________________ 27 

schencki, Dentalium __________________ 5, 15, 35, pl. 5 

Thracia ____________ 6, 10, 13, 14, 16, 17,34, pl. 9 

scopulosum, Sinum ______________ 4, 5, 14, 22, pl. 1 

scopulosus, Sigaretus ___ __________________________ 4 

secta, Macoma ________ 6, 12, 14, 15, 19, 20, 33, pl. 8 

Securella _________________ _____________________ 34 

alaskensis __________________________________ 34 

ensifera ___ _ ________ 4, 6, 14, 15, 33, pl. 9 

securis, Chione _________________________________ 4 

Seiku _ --------------------------------- ________ 7 

Semicassis ____ _ 19, 23 

aequisulcatum ----------------------------- 22 

pyshtensis __________ 4, 5, 11, 14, 15, 20, 22, pl. 1 

centiquadrata ___________ 23 

iani _______________________________________ 22 

43 

Page 

Shark teeth ______________ ----------------------- 4 

Sigaretus scopulosus ___________________ 4 

siletzensis, Cancellaria ____________ 5, 11, 15, 25, pl. 2 

simplex, Cancellaria ______________ 5, 12, 15, 25, pl. 2 

Sinum scopulosum ---------------- 4, 5, 14,22, pl. 1 

Slip Point ______________ 3, 7, 8, 9, 12, 18, 19, 21, 23, 

24, 27, 28, 30, 34 

slipensis, Priscofusus ____________ 4, 5, 15, 20,24, pl. 2 

Snavely, Parke D. Jr., cited ______________________ 29 

snauelyi, Solamen ______________ 4, 5, 14, 20, 29, pl. 4 

Soh!, N. F., cited -------------------------------- 20 

Solamen ------------------------------------ 18, 29 

porterensis ---------------------------- 29, pl. 4 

snavelyi ____________________ 4, 5, 14, 20, 29, pl. 4 

Solemya ________ -________________________________ 28 

Solemyidae ______________________________________ 28 

Solen __________________________________________ 31 

conradi ---------------------------- 6, 14,31, pl. 6 

Solenidae __________________________ ------------ 31 

Sooke Formation, fauna __________________________ 20 

Vancouver Island ______ 21, 22, 24, 25, 26, 30, 31 

sookensis, Clinocardium __________________________ 31 

Crepidula ---------------------------------- 22 

Macoma ______________________ 6, 14, 33, pis. 7, 8 

Spisula ________________ 6, 10, 13, 14, 16,31, pl. 6 

Trochita ____________________________________ 21 

Species, index ---------------------------------- 27 

Spencer Creek, Lincoln County, Oreg ____________ 25 

spirata, Trochita -------------------------------- 21 

Spirotropis washingtonensis ---------------------- 26 

Spisula _______________________________________ - 31 

albaria ________________ 4, 5, 14, 15,31, pis. 6, 7 

goodspeedi ____________ 5, 10, 14,31, pis. 6, 7 

catilliformis -------------------- ____________ 31 

equilateral is ________________________________ 31 

hannibali ______________ 5, 10, 13, 14, 16,31, pl. 6 

sookensis ______________ 6, 10, 13, 14, 16,31, pl. 6 

sp ---------------------------------- 6, 31, pl. 6 

Stanford University collections __________________ 20 

stewarti, Priscofusus ____ 5, 10, 11, 15, 16, 24, 25, pl. 2 

submontereyana, Anadara ________________________ 28 

substriata, Xylotrya ------------------------------ 4 

substriatum, Dentalium -------------------------- 4 

subtenta, Cyclocardia __________ 5, 14, 15, 30, pis. 5, 6 

quadrata, Venericardia ---------------------- 30 

supramontereyensis, Yoldia ______ 4, 5, 14, 19, 27, pl. 3 

Surian molluscan province _____________________ 20 

T 

Taylor, D. W., cited _____________________________ 20 

teglandae, Ancistrolepis clarki ____________________ 23 

Tellina arctata -------------------------------- 3, 4 

arctatajuana ------------------------ 4, 32, pl. 7 

clallamensis ------------------------ 4, 32, pl. 7 

emacerata __________________ 4, 6, 14, 15,31, pl. 7 

oregonensis __ ------------------------------- 4 

(0udardial sp ------------------------------ 32 

Tellinids ______________________________ 12, 19, 31, 32 

Tellinidae ______________________________________ 31 

Temblor Formation------------------------------ 13 

Temblor Stage ------------------------------ 16, 20 

central California ____________________ 12, 16, 17 

tenuissima, Yoldia ------------------------------ 27 

Teredo bulbosus ---------------------------------- 4 

sp ------------------------------------------ 4 

Thesbia antiselli _______________________________ 26 

Thracia ________________________________________ 18 

condoni __________________________________ 34 

schencki ____________ 6, 10, 13, 14, 16, 17, 34, pl. 9 

trapezoides ____________ 6, 14, 15, 18, 19, 34, pl. 9 

Thraciidae ____________________________________ 34 

Thyasiridae __________________________ ---------- 30 

tichanovitchi, Mytilus __ 5, 13, 14, 16, 19, 20,28, pl. 5 

trapezoides, Thracia ________ 6, 14, 15, 18, 19, 34, pl. 9 

trochiformis, Trochita ____ ----------------------- 21 

Trochita ------------------------------------ 19, 20 

fi losa __ ------------------------------------ 21 

inornata ------------------------------------ 4 

sookensis ___________________________________ 21 
44 

Page 

Trochita-Continued 

spirata ____________________________________ 21 

trochiformis ________________________________ 21 

n. sp ______________________ 5, 14, 15, 20, 21, pl. 1 

Trophonopsis -------------- ______________________ 23 

sp ---------------------------------- 5, 23, pl. 2 

Trophosycon clallamensis ______ 5, 14, 15,23, pis. 1, 2 

kernianum --------------------------------- 23 

Turner, D. L., cited------------------------------ 27 

Turridae -------------------------------------- __ 26 Turritella ______________________________________ 21 

oregonensis ---------------------- 5, 14,21, pl. 1 

yaquinana __ __________________________________ 7 

Turritellidae ____________________________________ 21 

Twin River---------------------------------- 32, 34 

Twin River Formation ______________ 1, 3, 6, 7, 9, 16, 

28, 30, 32, 33, 34 

age------------------------------------------ 7 

benthonic foraminiferal assemblages __________ 18 

contact______________________________________ 16 

depositional environment ________________ 18, 20 

faunal hiatus ________________________________ 16 

molluscan assemblages ________________________ 7 

mollusks ---------------------------------- 2, 7 

twinensis, Macoma __ 6, 10, 11, 13, 14, 16,32, pis. 6, 7 

u 

Ungulinidae ____ _ -------------- 30 

INDEX 

U.S.G.S. fossil localities ______ _ 

Page 

19,35 

v 

Vancouver Island __ ----------------------------- 21 

British Columbia, Canada ______ 22, 24, 26, 31, 33 

Vaqueros Formation ___________________________ 31 

Vaqueros Stage------------------------------ 20, 35 

California ____________________ 12, 13, 16, 17, 18 

Venericardia subtenta quadrata __________________ 30 

Veneridae ______________________________________ 33 

ventricosa, Archarax ---------------------------- 28 

Venus clallamensis ________________________ 34, pl. 9 

olympidea ---------------------------- 34, pl. 9 

(Chione) angustifrons ------------------------ 4 

clallamensis ------------------------------ 4 

olympidea -------------------------------- 4 

Vertipecten fucanus __________________ 4, 5, 10, 13, 14, 

15, 16, 17, 27, 29, pl. 4 

sp _ _ __ _ _ __ __ _ _ _ _ __ __ _ _ _ _ __ _ _ __ _ _ _ _ __ _ _ __ __ __ 17 

victorianus, Polinices ________________ 5, 14,22, pl. 1 

vokesi, Natica ________________________ 5, 14, 22, pl. 1 

Volutidae ______________________________________ 25 

w 

Washington __ _ -------------- 24 

depositional cycle ________________________ 11, 18 

molluscan province ________________________ 2, 3 

Page 

washingtonensis, Spirotropis ______________ ________ 26 

wattsi morani, Pecten (Chlamys) __________________ 4 

Weaver, C. E., cited ______________________________ 27 

weaveri, Musashia ------------------------------ 17 

whitneyi, Dosinia ____________________ 6, 14, 33, pl. 8 

willapaensis, Archarax -------------------------- 28 

workensis, Ophiodermella ________________________ 26 

wynoocheensis, Cancellaria ________ 5, 12, 15, 26, pl. 2 

Megasurcula __________________ 5, 15, 19, 27, pl. 3 

X 

Xenuroturris antiselli ______________ 5, 15,26, pis. 2, 3 

Xylotrya substriata __ ______________________________ 4 

y 

Yakataga Formation, Gulf of Alaska __________ 31,34 

yakatagense, Clinocardium ---------------------- 31 

yakatagensis, Cyclocardia ------------------------ 30 

yaquinana, Bruclarkia ____________ 5, 14, 15, 23, pl. 2 

Turritella ------------------------------------ 7 

Y oldia __ ------------------------------- _________ 27 

impressa ------------------------------------ 4 reagani ______________________________________ 4 

supramontereyensis -------- 4, 5, 14, 19, 27, pl. 3 

tenuissima ---------------------------------- 27 

z 

Zemorrian Stage -------------------------------- 16 
PLATES 1-9 

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 specimens are from the Clallam Formation] 

FIGURES 1, 22. Crepidula praerupta Conrad. 

1. Length 43 mm, width 24 mm. USNM 215926. USGS loc. M5886. 

22. Length 22 mm, width 18 mm. USNM 215927. USGS loc. M4050. 

2, 3. Semicassis pyshtensis, n. sp. 

Holotype. Height 42 mm, width 28 mm. USNM 215928. USGS loc. M4414. 

4, 5, 20, 24. Neveritajamesae Moore. 

4, 5. Height 20 mm, width 24 mm. SUPTC 10182. SU loc. NP161. 

20, 24. Height 11 mm, width 15 mm. USNM 215929. USGS loc. M4684. 

6, 7. Crepidula princeps Conrad. 

6. Length 42 mm, width 26 mm. USNM 215930. USGS loc. M5886. 

7. Length 37 mm, width 19 mm. USNM 215931. USGS loc. M4414. 

8, 13. Epitonium clallamense Durham. 

8. Height 24 mm, width 14 mm. USNM 215932. USGS loc. M4413. 

13. Height 28 mm, width 18 mm. USNM 215933. USGS loc. M4413. 

9, 12, 18. Trochita n. sp. Moore. 

9. Height 11 mm, width 31 mm. USNM 215934. USGS loc. M4678. 

12. Height 14 mm, width 32 mm. USNM 215935. USGS loc. M4681. 

18. Height 9 mm, width 20 mm. USNM 215936. USGS loc. M4049. 

10, 11, 17. Turritella oregonensis (Conrad). 

10. Height 18 mm, width 4 mm. USNM 215937. USGS loc. M4049. 

11. Height 18 mm, width 8 mm. USNM 215938. USGS loc. M4049. 

17. Height 14 mm, width 8 mm. USNM 215939. USGS loc. M4049. 

14-16. Natica vokesi Addicott. 

14, 15. Height 17 mm, width 19 mm. USNM 215940. USGS loc. M4680. 

16. Height 13 mm, width 14 mm. USNM 215941. USGS loc. M4680. 

19, 27, 28. Natica cf. N. clarki Etherington. 

19. Height 15 mm, width 18 mm. USNM 215942. USGS loc. M5886. 

27. Height 7 mm, width 9 mm. USNM 215943. USGS loc. M4681. 

28. Height 12 mm, width 13 mm. USNM 215944. USGS loc. M5886. 

21, 26. Sinum scopulosum (Conrad). 

Height 13 mm, width 19 mm. USNM 215945. USGS loc. M4678. 

23. Crepidula sp. 

Height 10.5 mm, width 16 mm. USNM 215946. USGS loc. M4683. 

25. Polinices victorianus Clark and Arnold. 

Height 16 mm, width 17 mm. USNM 215947. USGS loc. M4681. 

29, 30. Ficus modesta (Conrad). 

Height 53 mm, width 40 mm. USNM 215948. USGS loc. M4678. 

31. Trophosycon clallamensis (Weaver). 

Height 78 mm, width 55 mm. SUPTC 10183. SU loc. NP89. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 976 PLATE 1 

6 

12 

18 

27 

28 

3 

9 

10 

8 

7 

13 15 16 

20 22 

24 25 26 

29 30 31 

CREPIDULA, SEM!CASSIS, NEVER!TA, EPITONIUM, TROCHITA, TURRITELLA, 

NA T!CA, SINUM, POL!NICES, FICUS, TROPHOSYCON 

11 

17 

23 
PLATE 2 

[Specimens are from the Clallam Formation unl ess otherwise specified] 

FIGURES 1- 3. Bruclarkia oregonensis (Conrad). 

1. Height 40 mm, width 30 mm. USNM 215949. USGS Joe. M4678. 

2, 3. Height 43 mm, width 28 mm. USNM 215950. USGS Joe. M4678. 

4, 6, 19. Bruclarkia cf. B. oregonensis (Conrad). 

4. Height 29 mm, width 19 mm. USNM 215951. USGS Joe. M 4051. 

6. Height 24 mm, width 15 mm. USNM 215952. USGS Joe. M4051. 

19. Height 23 mm, width 13 mm. USNM 215953. USGS Joe. M4050. 

5, 7- 9. Bruclarkia yaquinana (Anderson and Martin). 

5. Height 34 mm, width 30 mm. SUPTC 10184. SU Joe. NP89. 

7. Height 25 mm, width 17 mm. USNM 215954. USGS Joe. M4050. 

8. Height 22 mm, width 15 mm. USNM 215955. USGS Joe. M4050. 

9. Height 17 mm, width 17 mm. USNM 215956. USGS Joe. M4051. 

10, 11. Molopophorus newcombei (Merriam). 

10. Height 29 mm, width 16 mm. USNM 215957. USGS Joe. M4060, Sooke Formation, 

lower Miocene, southwest coast of Vancouver Island, British Columbia. 

11. Height 34 mm, width 18 mm. USNM 215958. USGS Joe. M4060 , Sooke Formation, 

lower Miocene, southwest coast of Vancouver Island, British Columbia. 

12. Priscofusus aff. P. geniculus (Conrad). 

Height 28 mm, width 16 mm. USNM 215959. USGS Joe. M4049. 

13. Priscofusus slipensis, n. sp. 

Holotype. Height 27 mm, width 16 mm. UW 13337. UW Joe. 490. 

14, 17, 18, 21. Priscofusus goweri, n. sp. 

14. Paratype. Height 16 mm, width 8 mm. USNM 215960. USGS loe. M4049. 

17. Paratype. Height 18 mm, width 8 mm. USNM 215961. USGS Joe. M4049. 

18. Holotype. Height 18 mm, width 8 mm. USNM 215962. USGS Joe. M4049. 

21. Paratype. Height 23 mm, width 12 mm. USNM 215963. USGS Joe. M4049. 

15. Priscofusus ef. P. stewarti (Tegland). 

Height 19 mm, width 13 mm. USNM 215964. USGS Joe. M4049. 

16. Molopophorus n. sp. aff. M. newcombei (Merriam). 

Height 26.5 mm, width 18 mm. USNM 215965. USGS loc. M5879. 

20. Trophonopsis sp. 

Height 10 mm, width 6 mm. USNM 215966. USGS Joe. M4677. 

22. Xenuroturris antiselli (Anderson and Martin). 

Height 11 mm, width 6 mm. USNM 215998. USGS Joe. M4683. 

23, 25. Crepidula rostra/is (Conrad). 

Length 27 mm, width 19 mm, height 13.5 mm. USNM 215967. USGS Joe. M4051. 

24. Crepidula praerupta Conrad. 

Length 22 mm, width 18 mm, height 15 mm. USNM 215967. USGS Joe. M4050. 

26--28. Cancellaria cf. C. oregonensis Conrad. 

26. Height 14 mm, width 7 mm. USNM 215969. USGS loe. M4675. 

27, 28. Height 13 mm, width 7 mm. USNM 215970. USGS Joe. M4049. 

29. Cancellaria cf. C. siletzensis Hanna. 

Height 19 mm, width 11.5 mm. USNM 215971. USGS loc. M4049. 

30, 31. Cancellaria cf. C. simplex Anderson. 

30. Height 23 mm, width 17 mm. USNM 215972. USGS Joe. M4049. 

31. Height 24 mm, width 17 mm. USNM 215973. USGS Joe. M4049. 

32, 35, 38. Cancellaria wynoocheensis Weaver. 

32. Height 16 mm, width 16 mm. USNM 215974. USGS Joe. M4049. 

35. Height 19.5 mm, width 13.5 mm. USNM 215975. USGS Joe. M4049. 

38. Height 23 mm, width 14.5 mm. USNM 215976. USGS loc. M6375. 

33. ?Rectiplanes sp. 

Height 17.5 mm, width 8 mm. USNM 215977. USGS loc. M4049. 

34. Trophosycon clallamensis (Weaver). 

Height 22 mm, width 21 mm. USNM 215978. USGS Joe. M4051. 

36, 37. Cancellaria birchi Addieott. 

Height 12 mm, width 6 mm. USNM 215979. USGS Joe. M5879. 
GEOLCK;ICAL SURVEY PROFESSIONAL PAPER 976 PLATE 2 

12 

19 

33 

2 3 4 

9 10 

13 14 15 16 17 

21 22 23 24 

20 

30 31 

27 28 29 

34 35 36 37 

BRUCLARKIA, MOLOPOPHORUS, PRISCOFUSUS, TROPHONOPSIS, CREPIDULA, 

CANCELLARIA, RECTIPLANES, TROPHOSYCON 

5 

11 

18 

25 

38 
PLATE 3 

[Specimens are from the Clallam Formation unless otherwise specified I 

FIGURES 1- 3. Acila Conradi (Meek). 

1. Length 19 mm, height 16 mm. SUPTC 10185. SU Joe. NP163. 

2. Length 21.5 mm, height 19 mm. USNM 215980. USGS Joe. 

M4681. 

3. Length 22 mm, height 19 mm. USNM 215981. USGS Joe. M4681. 

4, 6, 10, 12-14. Nuculana calkinsi (Moore). 

4. Length 17 mm, height 10 mm. USNM 215982. USGS Joe. M4677. 

6. Length 14 mm, height 8.5 mm. USNM 215983. USGS Joe. 

M4677. 

10. Length 30 mm, height 18 mm. USNM 215984. USGS Joe. M4049. 

12, 13. Length 19.5 mm, height 11 mm. USNM 215985. USGS Joe. 

M5878. 

14. Length 16 mm, height 10 mm. USNM 215986. USGS Joe. M4049. 

5. Archarax dalli (Clark). 

Length 61 mm, height 22 mm. USNM 215987. USGS Joe. M4050. 

7, 15. Y oldia supramontereyensis Arnold. 

7. Length 41 mm, height 27 mm. USNM 215988. USGS Joe. M4680. 

15. Length 24 mm, height 13 mm. USNM 215989. USGS Joe. M4680. 

8, 9. Nuculana ef. N. elmana Etherington. 

Length 21 mm, height 12 mm. USNM 215991. USGS Joe. M6375. 

11. Nuculana chehalisensis (Weaver). 

Length 14 mm, height 8 mm. USNM 215990. USGS Joe. M4678. 

16, 17. Megasurcula ef. M. wynoocheensis (Weaver). 

Height 31 mm, width 15 mm. UW 13339. UW Joe. 490. 

18--20, 22. Ophiodermella olympicensis, n. sp. 

18. Holotype. Height 16 mm, width 6.5 mm. USNM 215992. USGS 

Joe. M4051. 

19. Paratype. Height 14.5 mm, width 8 mm. USNM 215993. USGS 

Joe. M4051. 

20. Paratype. Height 11.5 mm, width 8 mm. USNM 215994. USGS 

Joe. M4051. 

22. Paratype. Height 17 mm, width 8 mm. USNM 215995. USGS Joe. 

M4051. 

24, 25. Ophiodermella cf. 0. olympicensis Addicott, n. sp. 

24. Height 20 mm, width 8 mm. USNM 215996. USGS Joe. M2514, 

Astoria Formation, lower or middle Miocene, Grays River 

quadrangle, southwestern Washington. . 

25. Height 14 mm, width 8 mm. USNM 215997. USGS Joe. M2514, 

Astoria Formation, lower or middle Miocene, Grays River 

quadrangle, southwestern Washington. 

21, 23. Xenuroturris antiselli (Anderson and Martin). 

21. Height 11 mm, width 6 mm. USNM 215998. USGS Joe. M4683. 

23. Height 13 mm, width 6 mm. USNM 215999. USGS Joe. M4683. 

26. Ancistrolepis rearensis (Clark). 

Height 47 mm, width 28 mm. UW60271. UW Joe. 490. 

27. Musashia indurata (Conrad). 

Height 74 mm, width 34 mm. USNM 216000. USGS Joe. M4050. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 976 PLATE 3 

8 

12 

16 

22 

2 3 

6 

10 

9 

13 14 

20 

19 

17 18 

23 24 25 26 

ACILA, NUCULANA, ARCHARAX, YOLDIA, MEGASURCULA, OPHIODERMELLA, 

XENUROTURRIS, ANCISTROLEPIS, MUSASH!A 

4 

7 

11 

15 

27 
PLATE 4 [Specimen~ are from the Clallam Formation unless otherwise specified J 

FIGURES 1, 2, 5, 7, 10, 12. Vertipecten fucanus (Dall). 

1. Length 64 mm, height 68 mm. USNM 216001. USGS loc. 

M4049. 

2. Length 79 mm, height 75 mm. USNM 216002. USGS loc. 

M4414. 

5. Length of fragment 56 mm. USNM 216003. USGS loc. M4678. 

7. Length 46 mm, height 44 mm. USNM 216009. USGS loc. 

M4049. 

10. Length 51 mm, height 60 mm. USNM 215968. USGS loc. 

M4678. 

12. Length 80 mm, height 85 mm. USNM 216004. USGS loc . 

M4049. 

3, 11. Solamen porterensis (Weaver). 

Length 10 mm, height 12 mm. USNM 216005. USGS loc. 18977, 

Lincoln Creek Formation, upper Oligocene, Grays Harbor basin, 

southwestern Washington. 

4, 8. Dentalium pseudonyma Pilsbry and Sharp. 

4. Length 28 mm, width 6 mm. SUPTC 10188. SU Joe. NP89. 

8. Length 19 mm, width 4 mm. USNM 216006. USGS Joe. M4049. 

6, 9. Solamen snavelyi, n. sp. 

6. Para type. Length 14 mm, height 19 mm. USNM 216007. USGS 

loc. M4050. 

9. Holotype. Length 14 mm, height 21 mm. USNM 216008. USGS 

loc. M4051. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 976 PLATE 4 

7 

5 

9 

10 11 12 

VERT/PECTEN, SOLAMEN, DENT ALlUM 
PLATE 5 

[Specimens are from the Clallam Formation unless otherwise specified J 

FIGURES 1, 2, 16, 18. Mytilus n. sp. aff. M. tichanovitchi Makiyama. 

1. Length 42 mm, height 82 mm. SUPTC 10189. SU loc. NP89. 

2. Length 36 mm, height 84 mm. SUPTC 10190. SU loc. NP89. 

16, 18. Length 38, height 102 mm. SUPTC 10191. SU loc. NP89. 

3. Glycymeris sp. 

Length 27 mm, height 26 mm. USNM 216010. USGS loc. M4684. 

4, 7, 15. Lucinoma acutilineata (Conrad). 

4. Length 26 mm, height 23 mm. USNM 216011. USGS loc. M4050. 

7. Length 38 mm, height 35 mm. SUPTC 10192. SU loc. NP163. 

15. Length 33 mm, height 32 mm. USNM 216012. USGS loc. M4414. 

5. Modiolus n. sp.? aff. M. restorationensis Van Winkle. 

Length 29 mm, height 56 mm. USNM 216013. USGS loc. M4050. 

6. Anadara cf. A. devincta (Conrad). 

Length 40 mm, height 29 mm. USNM 216014. USGS loc. M4678. 

8, 9. Anadara aff. A. lakei (Wiedey). 

8. Length 40 mm, height 32 mm. USNM 216015. USGS loc. M4050. 

9. Length 32 mm, height 27 mm. USNM 216016. USGS loc. M4050. 

10. Anadara deuincta (Conrad). 

Length 44 mm, height 32 mm. USNM 216017. USGS loc. M4678. 

11. Dentalium schencki Moore. 

Length 38 mm, width 8 mm. USNM 216018. USGS loc. M4049. 

12. Cyclocardia subtenta (Conrad). 

Length 21 mm, width 20 mm. USNM 216019. USGS loc. M5878. 

13. Clinocardium n. sp. aff. C. nuttalli (Conrad) Moore. 

Length 38 mm, width 36 mm. USNM 216020. USGS loc. M4681. 

14. Mytilus tichanovitchi Makiyama. 

Length 135 mm, height 79 mm. USNM 216021. Ashai Formation, 

Miocene, central Hokkaido, Japan (Kanno and others, 1968). 

17. Felaniella sp. 

Length 22 mm, height 22 mm. USNM 216022. USGS loc. M4413. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 976 PLATE 5 

3 

7 

5 

4 

9 

8 

13 

15 

17 

MYTILUS, GLYCYMERIS, LUC/NOMA, MODIOLUS, ANADARA, DENTALIUM, 

CYaOCARDIA, CLINOCARDIUM, FELAN/ELLA 

6 

10 

18 
FIGURES 

PLATE 6 

!Specimens are from the Clallam Formation unless otherwise specified ] 

1, 16. Spisula sookensis Clark and Arnold. 

1. Length 64 mm, height 57 mm. USNM 216023. USGS lac. M4049. 

16. Length 81, height 70 mm. SUPTC 10193. SU loc. NP89. 

2, 4, 13, 15. Macoma twinensis Clark. 

2, 4. Length 31 mm, height 22 mm. USNM 216024. USGS lac. M4032. 

Upper member of the Twin River Formation, lower Miocene, 

western Washington. 

13, 15. Length 26 mm, height 18 mm. USNM 216025. USGS loc. 

M4032. Upper member of the Twin River Formation, lower 

Miocene, western Washington. 

3. Spisula albaria (Conrad). 

Length 54 mm, height 46 mm. USNM 216026. USGS loc. M4051. 

5. Macoma cf. M. twinensis Clark. 

Length 23 mm, height 14 mm. USNM 216027. USGS loc . M4677. 

6. Spisula sp. 

Length 65 mm, height 48 mm. USNM 216028. USGS loc. M4049. 

7. Conchocele disjuncta Gabb. 

Length 43 mm, height 51 mm. USNM 216029. USGS loc. M4050. 

8. Clinocardium n. sp. aff. C. nuttalli (Conrad) Moore. 

Length 43 mm, height 43 mm. USNM 216030. USGS loc. M4049. 

9, 10. Cyclocardia subtenta (Conrad). 

9. Length 20 mm, height 20 mm. USNM 216031. USGS loc. M4049. 

10. Length 15 mm, height 15 mm. USNM 216032. USGS loc. M4677. 

11. Spisula cf. S. hannibali Clark and Arnold. 

Length 65 mm, height 46 mm. USNM 216033. USGS loc. M4675. 

12. Solen conradi Dall. 

Length 43 mm, height 13 mm. USNM 216034. USGS lac. M4050. 

14. Spisula albaria goodspeedi Etherington. 

Length 58 mm, height 49 mm. USNM 216035. USGS loc. M4414. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 976 PLATE 6 

2 

4 

3 

5 

8 

7 

9 

12 

11 

10 

13 

14 15 16 

SPISULA , MACOMA, CONCHOCELE, CLINOCARD!UM, CYCLOCARDIA, SOLEN 
FIGURES 

PLATE 7 

[Specimens are from the Clall am Formation unless otherwise spcciflcd] 

1. Spisula albaria goodspeedi Etherington. 

Length 49 mm, height 40 mm. USNM 216036. USGS Joe. 

M4049. 

2, 3, 11. Spisula albaria (Conrad). 

2, 3. Mactra gibbsana Meek of Reagan (1909). Length 55 mm, 

height 40 mm. USNM 32832. Probably from the east side 

of Clallam Bay near Slip Point. 

11. Length 31 mm, height 25 mm. USNM 216037. USGS Joe. 

M4051. 

4, 6, 8, 14, 18, 22. Macoma arctata (Conrad). 

4. Length 52 mm, height 31 mm. USNM 216038. USGS Joe. 

M4051. 

6. Length 41 mm, height 25 mm. USNM 216039. USGS Joe. 

M4051. 

8. Length 50 mm, height 32 mm. USNM 216040. USGS Joe. 

M5886. 

14. Holotype of Tellina arctata var. Juana Reagan (1909). 

Length 55 mm, height 33 mm. USNM 328319. Near Slip 

Point. 

18. Length 45 mm, height 28 mm. USNM 216041. USGS Joe. 

M4049. 

22. Length 61 mm, height 35 mm. USNM 216042. USGS Joe. 

M4049. 

5, 7, 10. Tellina emacerata Conrad. 

5. Length 37 mm, height 21 mm. USNM 216043. USGS Joe. 

M4684. 

7. Length 32 mm, height 18 mm. USNM 216044. USGS Joe. 

M4051. 

10. Holotype of Tellina clallamensis Reagan (1909). Length 33 

mm, height 19 mm. USNM 328320. Near Slip Point. 

9. Macoma cf. M. astori Dall. 

Length 38 mm, height 28 mm. USNM 216045. USGS Joe. 

M4049 . 

12. Macoma twinensis Clark. 

Length 34 mm, height 23 mm. USNM 216048. USGS Joe. 

M4032. Upper member of the Twin River Formation, lower 

Miocene, western Washington. 

13-15, 17, 20. Macoma albaria Conrad. 

13, 17, 20. Length 22 mm, height 15 mm. USNM 216046. USGS 

Joe. M4050. 

14, 15. Length 17 mm, height 12 mm. USNM 216047. USGS Joe. 

M4677. 

16, 19. Macoma arnoldi Tegland. 

Length 32 mm, height 26 mm. USNM 216049. USGS Joe. 

M4042. Blakeley Formation, upper Oligocene, Restoration 

Point, Washington. 

21. Macoma astori Dall. 

Length 52 mm, height 46 mm. USNM 216050. USGS Joe. 

M4049. 

23. Macoma sookensis Clark and Arnold. 

Length 54 mm, height 41 mm. SUPTC 10194. SU Joe. NP161. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 976 PLATE 7 

2 3 

7 

6 

4 

10 11 

12 13 

16 17 

20 

19 

21 22 23 

SPISULA, MACOMA, TELLINA 
FIGURES 

PLATE 8 !Specime ~ arc from the Clallam Formation unless otherwi!:ie specified] 

1, 2, 5. Macoma sookensis Clark and Arnold. 

1. Length 58 mm, height 43 mm. SUPTC 10195. SU loc. NP161. 

2. Length 50 mm, height 48 mm. USNM 216051. USGS Joe. M4681. 

5. Length 49 mm, height 38 mm. USNM 216052. USGS Joe. M4681. 

3. Macoma flagleri Etherington. 

Length 44 mm, height 31 mm. USNM 216053. USGS Joe. M1495, Astoria Formation, lower or middle Miocene, Grays Harbor basin, 

southwestern Washington. 

4. Macoma n. sp. Moore. 

Length 46 mm, height 42 mm. USNM 216054. USGS Joe. M4683. 

6. Macoma n. sp. aff. M. secta (Conrad). 

Length 41 mm, height 30 mm. USNM 216055. USGS Joe. M4678. 

7, 8, 11- 18. Katherinella angustifrons (Conrad). 

7. Inflated form. Length 31 mm, height 30 mm. USNM 216056. USGS 

Joe. M4677. 

8, 11. Thin form. Length 37 mm, height 35 mm. USNM 216058. USGS 

Joe. M4049. 

12. Length 40 mm, height 36 mm. SUPTC 10196. SU Joe. NP163. 

13. Length 58 mm, height 45 mm. USNM 216057. USGS Joe. M4051. 

14, 16. Thin form. Length 41 mm, height 41 mm. USNM 216059. USGS 

Joe. M4050. 

15, 17. Inflated form. Length 46 mm, height 43 mm. USNM 216060. 

USGS Joe. M4050. 

18. Thin form. Length 64 mm, height 57 mm. USNM 216061, USGS loe. 

M4049. 

9, 10. Dosinia whitneyi (Gabb). 

9. Length 25 mm, height 22 mm. USNM 216062. USGS loc. 

M4684. 

10. Length 30 mm, height 31 mm. USNM 216063. USGS Joe. 

M4683. 
GEOL(X;ICAL SURVEY PROFESSIONAL PAPER 976 PLATE 8 

3 

6 

5 

4 

8 

9 10 

7 I 

J \ 

;# 

12 

11 

13 

15 

14 

16 17 18 

MACOMA, KATHER!NELLA, DOSJN!A 
PLATE 9 

[All specimens are from the Clallam Formation] 

FIGURES 1-3, 5, 6, 9, 10, 13. Securella ensifera (Dail). 

1. Length 55 mm, height 51 mm. USNM 216064. USGS loc. 

M4678. 

2. Length 42 mm, height 36 mm. USNM 216065. USGS loc. 

M4683. 

3. Holotype of Venus clallamensis Reagan (1909). Length 43 

mm, height 34 mm. USNM 328312. Near Slip Point. 

5. Length 49 mm, height 47 mm. SUPTC 10197. SU loc. NP89. 

6. Length 49 mm, height 40 mm. SUPTC 10198. SU loc. NP89. 

9. Length 39 mm, height 39 mm. USNM 216074. USGS loc. 

M4049. 

10. Length 33 mm, height 32 mm. USNM 216066. USGS loc. 

M4051. 

13. Holotype of Venus olympidea Reagan (1909). Length 35 mm, 

height 31 mm. USNM 328311. 

4, 12. Thracia trapezoides Conrad. 

4. Length 59 mm, height 45 mm. SUPTC 10199. SU loc. NP163. 

12. Length 34 mm, height 30 mm. USNM 216067. USGS loc. 

M4051. 

7, 8, 16. Panopea abrupta (Conrad). 

7. Length 53 mm, height 37 mm. USNM 216068. USGS loc. 

M4678. 

8. Length 50 mm, height 28 mm. USNM 216069. USGS loc. 

M4683. 

16. Length 78 mm, height 42 mm. USNM 216070. USGS loc. 

M4050. 

11, 14. Thracia cf. T schencki Tegland. 

11. Length 35 mm, height 23 mm. USNM 216071. USGS loc. 

M4051. 

14. Length 33 mm, height 20 mm. USNM 216072. USGS loc. 

M4051. 

15. Panopea ramonensis (Clark). 

Length 82 mm, height 43 mm. USNM 216073. USGS loc. 

M4678. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 976 PLATE 9 

2 3 

6 

5 

4 

8 9 

7 

13 

15 16 

SECURELLA , THRACIA, PANOPEA 

GPO 692-104