Oligocene Marine Mollusks from the 

Pittsburg Bluff Formation in Oregon 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 

Oligocene Marine Mollusks from the 

Pittsburg Bluff Formation in Oregon 

By ELLEN JAMES MOORE 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 

Systematic paleontology and stratigraphic 

relations of the mollusks-48 species 

representing 31 families are described; 

6 taxa are new 

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

THOMAS S. KLEPPE, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress Cataloging in Publication Data 

Moore, Ellen James 

Oligocene marine mollusks from the Pittsburg Bluff Formation in Oregon. 

(Geological Survey Professional Paper 922) 

Bibliography: p. 56-60. 

Includes index. 

Supt. of Docs. no.: I 19.16:922 

1. Mollusks, Fossil. 2. Paleontology-Oligocene. 3. Paleontology-Oregon. I. Title. II. Series. United States. Geological 

Survey Professional Paper 922. 

QE801.M774 564'.09795 76-608010 

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

Washington, D.C. 20402 

Stock Number 024-001-02775-5 
CONTENTS 

Page 

1\bstract -------------------------------------------------- 1 

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

History of investigation -------------------------------- 1 

Purpose and scope______________________________________ 2 

Preparation of collections ------------------------------ 2 

1\bbreviations------------------------------------------ 3 

1\nnotated chronology of reports dealing with Oligocene 

formations and fossils, with primary emphasis on Oregon 

and Washington, 1892-1975 __________________________ 3 

1\cknowledgments______________________________________ 10 

Pittsburg Bluff Formation---------------------------------- 10 

Stratigraphy ------------------------------------------ 10 

General features and geographic distribution ________ 10 

Type locality -------------------------------------- 11 

Type area ---------------------------------------- 11 

Check list of Pittsburg Bluff species ____________________ 14 

Ecology ---------------------------------------------- 16 

Relation to other Oligocene faunas in Oregon____________ 19 

Summary__________________________________________ 23 

1\ge -------------------------------------------------- 23 

Correlation _ _ ______ ___ _ ________ __________ _ _ ______ __ _ _ __ 25 

Systematic descriptions ------------------------------------ 29 

Class Gastropoda -------------------------------------- 29 

Family Trochidae ---------------------------------- 29 

Family 1\rchitectonicidae __________________________ 29 

Family Turritellidae ------------------------------ 29 

Family Epitoniidae -------------------------------- 30 

Family Calyptraeidae ------------------------------ 31 

Family Naticidae ---------------------------------- 31 

Family Neptuneidae ------------------------------ 33 

Family Buccinidae? -------------------------------- 35 

Page 

Systematic descriptions-Continued 

Class Gastropoda-Continued 

Family Fusinidae ---------------------------------- 36 

Family Fasciolariidae ------------------------------ 36 

Family Turridae ---------------------------------- 37 

Family Pyramidellidae ---------------------------- 40 

Family Acteonidae -------------------------------- 40 

Family Scaphandridae__ ___ _ _ _ _ _ _ _ _ _ __ ____ _ _ _ _ __ ____ 41 

Class Scaphopoda -------------------------------------- 41 

Family Dentaliidae -------------------------------- 41 

Class Pelecypoda -------------------------------------- 42 

Family Nuculidae ---------------------------------- 42 

Family Nuculanidae ------------------------------ 43 

Family Mytilidae ---------------------------------- 44 

Family Carditidae -------------------------------- 45 

Family Lucinidae ---------------------------------- 45 

Family Ungulinidae ________________________________ 46 

Family Cardiidae ---------------------------------- 47 

Family Veneridae _ _ __________ ________ ______ ________ 4 7 

Family Mactridae ---------------------------------- 49 

Family Mesodesmatidae ---------------------------- 50 

Family Tellinidae ---------------------------------- 50 

Family Solenidae ---------------------------------- 51 

Family Hiatellidae -------------------------------- 52 

Family Periplomatidae ---------------------------- 53 

Family Thraciidae -------------------------------- 54 

Class Cephalopoda ------------------------------------ 54 

Family Nautilidae -------------------------------- 54 

U.S. Geological Survey fossil localities in the Pittsburg Bluff 

Formation, middle Oligocene, northwestern Oregon ________ 55 

References cited____________________________________________ 56 

Index ---------------------------------------------------- 61 

ILLUSTRATIONS 

PLATE 1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

[Plates follow index] 

Architectonica, Crepidula, unidentified trochid?, Cryptonatica, Sinum, and Polinices. 

Neue rita. 

Bruclarkia, Opalia, Odostomia, Turritella, and Priscofusus. 

Eosiphonalia. 

M olopophorus. 

Perse. 

Spirotropis, Taranis, Suauodrillia, Dentalium, Scaphander, Acteon?, Acteon, and Aforia. 

Acila and N ucula. 

Litorhadia, Cyclocardia, and Y oldia. 

Lucinoma, Felaniella, and Nemocardium. 

Tellina? and Tellina. 

Pitar, Callista, and Crenella. 

Solena and Solen. 

Spisula. 

Panopea and Aturia. 

Thracia, ?Eruilia, and Cochlodesma. 

Naticids, Molopophorus, Perse, Acila, and Macrocallista. 

III 
IV CONTENTS 

Page 

FIGURE 1. Map showing location of area of study at Vernonia, Oreg ------------------------------------------------------ _____ 10 

2. Photograph showing type locality of Pittsburg Bluff Formation ------------------------------------------------ _____ 11 

3. Geologic sketch map of the Vernonia area showing fossil localities and location of measured sections _________________ 12 

4. Measured sections of the Pittsburg Bluff and adjacent formations, Vernonia area------------------------------------- 13 

5. Photograph showing contact between siltstone of the Keasey Formation and sandstone of the Pittsburg BluffFormation _ _ _ _ _ 13 

6. Photograph showing siltstone rip-up clasts in Pittsburg Bluff Formation--------------------------------------------- 13 

7. Correlation chart of selected middle Tertiary stratigraphic units in Alaska, Washington, and Oregon _________________ 27 

8. Sketch of growth-line sinus on Turritella pittsburgensis, n. sp ------------------------------------------------------- 30 

TABLES 

Page 

TABLE 1. Checklist of species at U.S. Geological Survey localities in the Pittsburg Bluff Formation arranged in approximate stratigraphic order________________________________________________________________________________________________ 15 

2. Holocene genera in the Pittsburg Bluff Formation and their preferred bottom sediment and water depth_______________ 17 

3. Distribution of molluscan genera in the lower, middle, and upper parts of the Keasey Formation and their occurrence in 

the Pittsburg Bluff and Eugene Formations____________________________________________________________________ 22 

4. Distribution of Pittsburg Bluff species in some other formations of late Eocene, Oligocene, and early Miocene age _ _____ 26 

5. Checklist of Oligocene mollusks in the upper part of the Eugene Formation in Oregon ------------------------------- 28 
OLIGOCENE MARINE MOLLUSKS FROM THE 

PITTSBURG BLUFF FORMATION IN OREGON 

By ELLEN jAMES MOORE 

ABSTRACT 

The first recorded collection of fossils from the Pittsburg Bluff 

Formation was identified by W. H. Dall in 1896 and was assigned to 

the Oligocene. This was the first marine fauna on the Pacific coast to 

be assigned to the Oligocene. Although the fauna was briefly regarded 

as Eocene in the early 1900's, it has since been referred to the 

Oligocene, then more precisely to the middle Oligocene, an assignment that still stands. 

The Pittsburg Bluff Formation occurs in northwestern Oregon, 

where fossiliferous exposures are found in streambanks and in cuts on 

highways, logging roads, and railways. The type area of the formation 

is along the Nehalem River near Pittsburg, Oreg., where a highway 

cut affords a good exposure of its lower part. Exposures of the 

Pittsburg Bluff Formation are relatively scarce; they are interrupted 

by broad areas of thick soil cover and dense vegetation. The formation 

is cut by minor visible faults, and there may be others that are not 

visible, so the mapping is uncertain in some places. 

The Pittsburg Bluff Formation conformably overlies the Keasey 

Formation (late Eocene and early Oligocene) and is conformably 

overlain by the Scappoose Formation (late Oligocene and early 

Miocene). Because parts of all these formations are lithologically 

similar, the stratigraphic position of a nonfossiliferous exposure is 

sometimes uncertain. New stratigraphic studies indicate, however, 

that contrary to the opinion of some previous investigators, the 

Pittsburg BluffFormation is conformable with the underlying Keasey 

Formation. 

The estimated maximum thickness for the entire formation is 200 

m; the thickest continuous measured section of the Pittsburg Bluff 

Formation is 100m thick. 

In the present investigation, fossils were collected from newly. 

measured sections. In addition, all the collections from the Pittsburg 

Bluff Formation on deposit in the U.S. National Museum have been 

studied, as well as those at the California Academy of Sciences, 

Stanford University, and the University of California at Berkeley. 

A total of 48 species of Oligocene mollusks representing 43 genera 

and 31 families are described; of these, 5 species and 1 subspecies are 

new, representing the genera Turritella, Opalia, Cryptonatica, Perse, 

N ucula, and Felaniella. The biologic affinities of all the species in the · 

formation are reconsidered, and the fauna is correlated with other 

Oligocene faunas. 

The fossil mollusks represent a death assemblage; it seems likely. 

that three habitats may be represented, one of deep water (about 

100 m), one of moderately shallow water (about 20 m), and one of: 

shallow nearshore water, partly intertidal. The remains of mollusks 

living in these dissimilar habitats were brought together by submarine grain flowage before being fossilized. The bottom sediment 

was sandy mud. Comparison with ranges of related living genera · 

indicates that the ocean temperature off the northern coast of Oregon, 

though cooler than it was in the Eocene and Miocene, was perhaps 

warmer than it is today. 

INTRODUCTION 

HISTORY OF INVESTIGATION 

The first description of the rocks in the bluff near 

Pittsburg was written by J. S. Diller (1896). In his report, Diller assigned the fossil mollusks collected from 

these rocks to the Oligocene on the basis of identifications made by W. H. Dall. This was the first marine 

fauna on the Pacific coast to be regarded as Oligocene. In 

1903, however, Dall described Callista pittsburgensis 

from Pittsburg and assigned it to the Eocene. But Clark 

(1915), after comparing the fossils from this section with 

other mid-Tertiary taxa of the Pacific coast, some of 

which had been dated by comparison at the generic level 

with mollusks in the type sections in Europe and by 

Lyell's method of percentage of living taxa, reassigned 

the molluscan fauna from the bluff near Pittsburg to the 

Oligocene, stating that it was distinct from those ofboth 

the Eocene and the Miocene. 

The term ~~Pittsburg Bluffs" was first used for early 

Oligocene strata of Oregon in a correlation diagram by 

Hertlein and Crickmay (1925, p. 254), but these men did 

not formally describe the formation. In 1927 Schenck 

described what he called the ~~Pittsburg Bluff 

sandstone," which he said overlaid the Keasey Shale, 

was of middle Oligocene age, and could be correlated 

with the Eugene Formation (early and middle 

Oligocene), the Tunnel Point Sandstone (middle 

Oligocene), and the Yaquina Formation (late Oligocene 

and early Miocene). 

In 1936 Schenck (1936, p. 44) defined the Acila 

shumardi Zone as delimited by the range of Acila 

shumardi and as being further identified by such forms 

as Bruclarkia columbiana (Anderson and Martin), 

Callista pittsburgensis Dall, and Molopophorus gabbi 

Dall. All are common in the Pittsburg Bluff Formation. 

Schenck and Kleinpell (1936) proposed the west coast 

term ~~Refugian Stage" for rocks laid down after the 

Tejon and before the Zemorrian. The Refugian Stage 

included the Acila shumardi Zone, and its upper part 

marked the last appearance of Acila shumardi, Callista 

pittsburgensis, Molopophorus gabbi, and Bruclarkia 

columbiana. 

1 
2 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON , 

Weaver (1937) suggested that the term ((Pittsburg 

Bluff Formation" be applied to the entire middle 

Oligocene sequence of sedimentary rocks in Columbia 

County, Oreg., and that the type area of the formation 

be considered the exposures between Pittsburg and Mist 

on the Nehalem River in Oregon. In 1942, in a publication on the paleontology of the marine formations of 

Washington and Oregon, he described and illustrated 

all of the then known species of mollusks from the 

Pittsburg Bluff Formation. 

Durham (1944) restricted the Pittsburg Bluff fauna to 

his Molopophorus gabbi Zone. Acila shumardi occurs in 

both his early and middle Oligocene faunas. 

Warren, Grivetti, and Norbisrath (1945) mapped the 

areal extent of the Pittsburg Bluff Formation in 

northwestern Oregon and divided the formation into 

two members. On the basis of the molluscan faunas, 

they believed the lower member and the lower part of 

the upper member to belong to the middle Oligocene 

Molopophorus gabbi zone (as used by Weaver and 

others, 1944). 

In 1946, Warren and Norbisrath described the 

Pittsburg Bluff Formation as follows: 

In the lower part of the Pittsburg Bluff Formation are fine-grained 

marine sandstones containing numerous fossils in layers along the 

bedding and in calcareous concretions. These richly fossiliferous 

sandstones seem to pass upward into coarser massive sandstone which 

interfingers with cross-bedded, nearshore, marine and brackishwater sandstone. Upward in the formation fossiliferous bands are less 

common. Toward the top of the formation fossils are few and thick beds 

of tuffaceous material are prominent. 

No subsequent reports dealing primarily with the 

Pittsburg Bluff Formation have been published; its age, 

however, has been regarded as provincial middle 

Oligocene in references to and correlations with the 

formation since 1946. 

PURPOSE AND SCOPE 

The original descriptions of mollusks found in the 

Pittsburg Bluff Formation are in many papers, none of 

which deal primarily with the fauna. Many of the 

original photographs, moreover, are inadequate, and 

much of the taxonomy is out of date. In this paper all the 

described mollusks are reillustrated and redescribed, 

and some needed corrections have been made in their 

taxonomy. Five new species and a new subspecies, 

representing six genera, are described and illustrated. 

Also included are new stratigraphic sections of the 

Pittsburg Bluff Formation measured in Columbia and 

Washington Counties, Oreg., near the type area; these 

are presented together with a geologic sketch map. 

The middle Oligocene mollusks found in the 

Pittsburg Bluff Formation are compared with other 

known Oligocene faunas of the Pacific coast of North 

America, and the geologic and geographic ranges of 

each species are given. Information on the ecology of 

related modern genera is tabulated, and this data, 

together with lithologic data, have been used to infer 

generalities concerning the Oligocene paleoenvironment. 

The type locality of Acila (Truncacila) shumardi 

(Dall) (sec. 23, T. 5 N., R. 4 W., Vernonia quadrangle) is 

in the type locality of the Pittsburg Bluff Formation. 

This mollusk lived throughout the Acila shumardi 

Zone, which has been recognized by various authors at 

localities ranging from Alaska to California. Schenck 

(1936, p. 42) proposed the ('Acila shumardi biozone" and 

accepted the definition of a biozone as ((a deposit formed· 

during the total existence of a species." He goes on to 

define the Acila shumardi Zone (1936, p. 44) as being 

((that group of beds *** identified by an assemblage of 

fossils including Acila (Truncacila) shumardi (Dall), 

Bruclarkia columbiana (Anderson and Martin), 

Macrocallista pittsburgensis Dall, and Molopophorus 

gabbi Dall, and limited by the upper and lower range of 

Acila shumardi." It would seem that he may have had 

an assemblage zone in mind when he proposed the Acila 

shumardi biozone. Although A. shumardi is especially 

useful in stratigraphic correlation, its usefulness is 

enhanced if the entire molluscan assemblage living 

with it is recognized and understood. This paper seeks to 

fulfill that purpose. 

PREPARATION OF COLLECTIONS 

Each collection of fossils taken from the Pittsburg 

Bluff area in the 1890's and early 1900's was given a 

U.S. Geological Survey locality number that designated 

a geographic position without regard to its stratigraphic 

interval. This was, of course, the usual practice at the 

time, but it gave a false impression regarding the taxa 

that were actually found together in a given lens or 

layer of rock. 

During field investigations conducted in the 1940's 

for the U.S. Geological Survey, H. E. Vokes collected 

many fossiliferous slabs from the Pittsburg Bluff 

Formation to aid in paleoecologic studies. The slabs 

average perhaps 8 x 15 x 20 em in overall size; two of 

them are shown on plate 17. These slabs, most of them 

from USGS localities 15264 and 15310, have been individually prepared as part of the present study, and on 

each specimen taken from a single slab the same letter 

has been put after the U.S. Geological Survey Cenozoic 

locality number, for example 15264a, to indicate what 

fossils were found together in the same slab. In other 

words, 15264 covers the general locality and 15264a, 

15264b, and so forth, refer to specimens from different 

slabs from that locality. 

Some pieces of rock that could not be prepared by 

ordinary mechanical means without loss of specimens 
INTRODUCTION 3 

were disintegrated by being soaked in kerosene and 

then heated in an oven at a temperature of 120°C. The 

samples were then washed through a 0.177-mm screen, 

which retained :mollusks of larger diameter and fish 

remains. Part of the fines from each sample was then 

washed through a 0.125-mm screen, but the only additional complete organic remains thus recovered were 

two globigerinid foraminifers. 

ABBREVIATIONS 

The following abbreviations are used in this report: 

USGS: U.S. Geological Survey, Washington, 

D. C., Cenozoic locality register. 

USGS M: U.S. Geological Survey, Menlo Park, 

Calif., Cenozoic locality register. 

UCMP: California U ni versi ty, Museum of 

CAS: 

SU: 

UW: 

UO: 

ANSP: 

Paleontology, Berkeley, Calif. 

California Academy of Sciences, San 

Francisco, Calif. 

Stanford University, Stanford, Calif. 

University of Washington, Seattle, 

Wash. 

University of Oregon, Eugene, Oreg. 

The Academy of Nat ural Sciences of 

Philadelphia, Philadelphia, Pa. 

ANNOTATED CHRONOLOGY OF REPORTS DEALING 

WITH OLIGOCENE FORMATIONS AND FOSSILS, WITH 

PRIMARY EMPHASIS ON OREGON AND WASHINGTON, 

1892-19751 

1892. Dall, W. H., and Harris, G. D. 

Assign the Eugene Formation of Oregon [now 

considered early and middle Oligocene] to the 

Miocene (p. 227). 

1896. Diller, J. S. 

Describes and assigns strata on the banks of the 

Nehalem River at Pittsburg Bluff, Oreg. to the 

Oligocene on the basis of fossil identifications made 

by W. H. Dall. None of the names used in Diller's 

report are currently applied to Pittsburg Bluff 

mollusks, as they were subsequently recognized as 

new species and so described. This is the first notice of 

the occurrence of Oligocene strata in the Pacific 

Northwest. The report includes a photograph of 

Pittsburg Bluff (pl. 7, opp. p. 466). 

Diller describes the lithology of strata at Pittsburg 

Bluff as follows: ~~The upper soft gray sandstone is 

very fossiliferous in places, and about 30 feet thick. 

Below are 20 feet of dark shales which weather gray 

*** Some of the layers of sand are indurated so as to 

form slabs, thickly set with perfectly preserved 

1Stratigraphic nomenclature used herein is that of the references cited and is not 

necessarily in accord with that of the U.S. Geological Survey. My comments are in brackets. 

fossils." [Diller did not always distinguish between 

the Keasey Formation, a shale now considered late 

Eocene and early Oligocene, and the shale that occurs 

in the Pittsburg Bluff Formation (p. 466).] On the 

Nehalem River ~~1 mile beyond Vernonia," he considered the Keasey to be part of the Pittsburg Bluff 

Formation. But at Wilson's Bluff on the river 3 miles 

above Vernonia, he does recognize a difference and 

states, ~~it is evident the shales above Vernonia are 

older than those at Pittsburg." 

1898. Dall, W. H. 

Tentatively assigns the Tunnel Point ~~beds" of 

Oregon [middle Oligocene] to the Oligocene (table 

opp. p. 334). 

1903 [1890-1903]. Dall, W. H. 

Describes and assigns Callista (Macrocallista) 

pittsburgensis from the strata at Pittsburg Bluff to 

the Eocene (p. 1253). 

1906. Arnold, Ralph. 

Assigns the Tunnel Point ~~beds" to the Oligocene 

and correlates them with part of the San Lorenzo 

Formation [late Eocene to middle Oligocene] of 

California (p. 10). A list of San Lorenzo Formation 

fossils is given (p. 17). 

1909. Dall, W. H. 

Describes two new species, Molopophorus gabbi (p. 

45) andEosiphonalia oregonensis (p. 51), from strata 

at Pittsburg Bluff, and gives the species, previously 

identified by Dallas Acila decisa (Conrad), the specific name shumardi (p. 103). Dall regards these fossils 

as Eocene. 

1914. Washburne, C. W. 

States (p. 73), in commenting on the fossils collected 

from beds exposed near Pittsburg that Dall called 

Eocene and Miocene, that those which Dall called 

Eocene appear to be higher stratigraphically than 

those that he called Miocene; he suggests (p. 7 4) that 

these fossils may in fact all be Oligocene. The fossil 

identifications made by Dall are given on page 31. 

1914. Anderson, F. M., and Martin, Bruce. 

Describe Agasoma columbiana from the Pittsburg 

Bluff Formation. 

1915. Clark, B. L. 

Assigns the fauna at Pittsburg Bluff to the 

Oligocene and lists the mollusks, comparing them 

with faunas from the Lincoln [Lincoln Creek] Formation of Washington [late Eocene to early Miocene], 

and the Oligocene of California. 

1916a. Weaver, C. E. 

Refers the Oligocene rocks of western Washington 

to the Clallam Formation [now considered middle 

Miocene], which he divides into three zones, characterized, in ascending order, by Molopophorus lincolnensis, Turritella porterensis, and Acila gettys-
4 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

burgensis. He calls the rock units containing these 

zones the Lincoln, Porter, and Blakeley ~~horizons," 

respectively. He notes that Acila shumardi and 

Callista pittsburgensis, two species common in the 

Pittsburg Bluff Formation, are especially common in 

the Molopophorus lincolnensis Zone. 

1916b. Weaver, C. E. 

Assigns mollusk species common in the Pittsburg 

Bluff Formation to the Molopophorus lincolnensis 

Zone of western Washington (p. 167). 

1916c. Weaver, C. E. _ 

Recognizes the Oligocene age (p. 17) of the Gries 

Ranch Formation [early Oligocene]. 

1916d. Weaver, C. E. 

Gives the sequence of post-Eocene for western 

Washington as follows: 

Montesano horizon-¥ oldia strigata Zone-upper 

Miocene 

Wahkiakum horizon-Area montereyana Zonelower Miocene 

Blakeley horizon-Acila gettysburgensis ZoneOligocene 

Porter horizon-Turritella porterensis ZoneOligocene 

Lincoln horizon-Molopophorus lincolnensis 

Zone-Oligocene 

[The Molopophorus lincolnensis and Turritella 

porterensis Zones contain mollusks that occur in the 

Pittsburg Bluff Formation.] 

1916e. Weaver, C. E. 

Gives a faunal list for the Acila gettysburgensis 

Zone, which he assigns to the late Oligocene. 

1917. Dickerson, R. E. 

Describes 35 new species from the vicinity of the 

Grecco Ranch House, 4 miles east of Vader, Wash. 

[Gries Ranch Formation, early Oligocene]. He regards 

this fauna as being littoral, of early Oligocene age, 

and subtropical; and he believes it to be a lower facies 

of Weaver's Molopophorus lincolnensis Zone. 

1918. Clark, B. L., and Arnold, Ralph 

Assign the Oligocene marine rocks of western 

Washington to the San Lorenzo Group and include 

Weaver's Lincoln, Porter, and Blakeley horizons and 

also the Sooke Formation of Vancouver Island (p. 

298). They believe the Oligocene of Oregon and 

Washington was deposited in geosynclinal depressions partly enclosed by land; one of these was probably a large trough between the Cascades and the 

Olympics. They recognize three faunas in 

Washington; these are, in decreasing order of age, the 

Agasoma acuminatum beds, the Molopophorus 

lincolnensis Zone, and theAcilagettysburgensis Zone. 

They believe the differences between the lower two 

faunas to be related to temperature. 

1918. Van Winkle, K. E. 

Divides the Porter beds of southwestern 

Washington into an upper part that she calls the 

Turritella porterensis Zone, and a lower part [Gries 

Ranch Formation] that she calls the Barbatia merriami Zone. She regards Lincoln Creek ~~beds" as 

equivalent to theMolopophorus lincolnensis Zone and 

to the middle part of the Porter beds. 

1918. Clark, B. L. 

Reports that Acila shumardi and Callista 

pittsburgensis, species common in the Pittsburg Bluff 

Formation, occur in the Kirker Tuff [Oligocene] of 

California and assigns the Pittsburg Bluff locality to 

the lower Oligocene (footnote 18, p. 59). He records 

the occurrence of Callista pittsburgensis Dall and 

Nuculana lincolnensis (Weaver) in the Kreyenhagen 

Shale of California [Eocene and Oligocene], which he 

assigns to the San Lorenzo Series (p. 63). 

Because certain species that occur in either the 

Molopophorus lincolnensis or the Acila gettysburgensis Zones occur together in the San Lorenzo in 

the Mount Diablo area, he does not believe that these 

zones represent distinct geologic horizons. 

His paper includes a comprehensive historical 

summary of the literature on the marine Oligocene of 

the Pacific coast (p. 57-72). 

1919. Smith, J. P. 

Points out that the Oligocene has fewer tropical 

genera than the Eocene and believes that although 

Oligocene faunas were already provincial, climatic 

zones had not yet been definitely established. He 

regards the Oligocene as oriental in its affinities, but 

considers both the Astoria [Miocene] and the San 

Lorenzo [late Eocene to middle Oligocene] Formations 

as Oligocene. 

1921. Clark, B. L. 

Places all the Oligocene in the San Lorenzo, which 

he divides into two parts, on his correlatio:Q. chart-a 

generalized section for Oregon, Washington, and 

northern California. He notes the occurrence of the 

typical Pittsburg Bluff species Acila shumardi and 

Callista pittsburgensis in the lower part of the San 

Lorenzo which he calls the ~~Molopophorus lincolnensis Zone". He correlates this zone with the 

Kreyenhagen Shale of California and the Vicksburg 

Group of the southeastern United States (table opp. p. 

586). He divides the Oligocene of the west coast into 

two subepochs; these subepochs are represented by 

the Molopophorus lincolnensis and Acila gettysburgensis Zones which are equivalent to the Lincoln 

and San Lorenzo Formations (p. 591-592). 

1923. Wagner, C. M., and Schilling, K. H. 

Correlate the San Emigdio [late Eocene and 

Oligocene] and Pleito [Oligocene] Formations of 
INTRODUCTION 5 

California with the Pittsburg Bluff Formation and 

give a list of fossils for the Pittsburg BluffFormation. 

1925. Clark, B. L. 

Describes two new species, Tellina pittsburgensis 

and Spisula pittsburgensis, from the type area of the 

Pittsburg Bluff Formation. 

1925. Hertlein, L. G., and Crickmay, C. H. 

First recognize the rocks exposed at Pittsburg Bluff 

as a stratigraphic unit and first call them the 

~~Pittsburg Bluffs." They believe these rocks to be of 

undoubted Oligocene age, possibly early Oligocene, 

and possibly equivalent to those exposed in San 

Emigdio Canyon, California (p. 254). 

1927. Schenck, H. G. 

Correlates the Y aquina Formation [late Oligocene 

and early Miocene], the Eugene Formation [early and 

middle Oligocene], and the Tunnel Point Sandstone 

[middle Oligocene], at least in part, on the basis of 

faunal evidence and reports that diagnostic species in 

each of these formations also occur in the Pittsburg 

Bluff Formation, which he assigns to the middle 

Oligocene. 

1928. Cushman, J. A., and Schenck, H. G. 

Tentatively regard the Bastendorf [Bastendorff] 

Shale and Keasey Formation as lower Oligocene; 

these formations are said to be of the same age and 

similar facies and to contain certain distinctive 

species of foraminifers. 

1928. Schenck, H. G. 

Describes the Pittsburg Bluff Formation, cites 

some of its molluscan fossils, and correlates it with 

the Eugene Formation [early and middle Oligocene], 

the Tunnel Point Formation [middle Oligocene], and 

the Yaquina Formation [late Oligocene and early 

Miocene]. He lists mollusks from the Eugene Formation, which in his opinion is equivalent to at least a 

part of the Molopophorus lincolnensis Zone of 

Washington. 

1929. Schenck, H. G. 

Gives evidence that the Pittsburg Bluff Formation 

is younger than the Tejon Formation [Eocene] and 

older than the Nye Shale [early Miocene] and that it 

probably represents the Lincoln-Porter horizon of 

Washington. He notes that some of the diagnostic 

species occurring in the Pittsburg Bluff Formation 

also occur between rocks of Tejon and Vaqueros 

[Eocene and Miocene] age in California. 

1929. Clark, B. L. 

Divides the Oligocene into three ~~faunal horizons." 

In Washington, he recognizes three horizons, in 

decreasing order of age, the Gries Ranch, Lincoln, and 

Restoration Point, but in California he recognizes 

only two horizons which he calls the Lincoln and San 

Ramon. He finds the following typical Pittsburg Bluff 

species in the ~~Lincoln horizon" of the San Emigdio 

Mountains of California: Acila shumardi, Callista 

pittsburgensis, and Bruclarkia columbiana (p. 18). 

1932. Clark, B. L. 

Believes the fauna of the Poul Creek [middle 

Oligocene to early Miocene] and Yakataga Formations [middle Miocene to early Pleistocene] of Alaska 

is the same and belongs to one zone-the Blakeley 

horizon of Washington. He regards the Blakeley 

horizon as late Oligocene and correlates it with the 

San Ramon Formation of California and the Sooke 

Formation of Vancouver Island. 

1936. Schenck, H. G. 

Correlates the Pittsburg Bluff Formation in part 

with the San Emigdio Formation [late Eocene and 

Oligocene] of California, and in part with the Lincoln 

[Lincoln Creek] Formation [late Eocene to early 

Miocene] of Washington (p. 65). 

He gives the name Acila shumardi Zone to a unit 

delimited by the range of Acila shumardi (Dall) (p. 

44). This unit is said to be about 3,000 feet thick in 

Columbia County, Oreg. Among its other diagnostic 

species are Bruclarkia columbiana (Anderson and 

Martin), Callista pittsburgensis Dall, and Molopophorus gabbi Dall. 

1936. Schenck, H. G., and Kleinpell, R. M. 

Propose the name Refugian Stage for rocks laid 

down after the Tejon Stage (restricted) and before the 

Zemorrian Stage. This stage includes the Eugene 

[early and middle Oligocene], Pittsburg Bluff[middle 

Oligocene], Tunnel Point [middle Oligocene], Keasey 

[late Eocene and early Oligocene], and Bastendorf 

[BastendorffJ [late Eocene and early Oligocene] 

Formations of Oregon, together with the Lincoln 

[Lincoln Creek] Formation [middle Oligocene] and the 

Gries Ranch Formation [early Oligocene] of 

Washington. The Refugian Stage includes the Acila 

shumardi Zone. The upper part of the Refugian Stage 

is marked by the last occurrence of Acila shumardi, 

Callista pittsburgensis, Molopophorus gabbi, and 

Bruclarkia columbiana, all of which are common in 

the Pittsburg Bluff Formation. 

1937. Weaver, C. E. 

Suggests that the term Pittsburg Bluff Formation 

be applied to the entire middle Oligocene sequence of 

sedimentary rocks in Columbia County, Oreg. and 

that the type area be considered the exposures between Pittsburg and Mist on the Nehalem River, 

Oreg. (p. 113). He states that fossils are scattered 

throughout the Pittsburg Bluff Formation but are 

especially abundant in lenses 2 to 6 inches thick, where 

they are so compacted as to form calcareous nodules (p. 

171). 

1937. Clark, H. L. 

Reports that a fossil sea urchin has been found in 
6 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

the waste from a well dug in sec. 12, T. 3 N., R. 4 W., 

that it is supposed to have come from the Pittsburg 

Bluff Formation. [Recent mapping done in connection 

with my report shows that it probably came from the 

Scappoose Formation of late Oligocene and early 

Miocene age.] 

1938. Effinger, W. L. 

Correlates the Gries Ranch Formation with the 

Keasey Formation and the lower part of the Pittsburg 

Bluff Formation, both of which he believes to be early 

Oligocene (fig. 3, p. 359). He regards the Gries Ranch 

fauna as subtropical and believes it to represent a 

nearshore or littoral facies (p. 360). 

1938. Clark, B. L., and Anderson, C. A. 

Show the Pittsburg Bluff and Eugene Formations 

as ~~lower Oligocene" on a correlation chart and 

correlate them with the Lincoln [Lincoln Creek] 

Formation of southwestern Washington and the San 

Lorenzo Group of California. They correlate the 

Wheatland Formation with the Keasey and Bastendorf [Bastendorff] Formations in Oregon and the 

Gries Ranch Formation in Washington and consider 

them to be of late Eocene or early Oligocene age (p. 

944). 

1938. Kleinpell, R. M. 

Assigns the type Lincoln [Lincoln Creek] Formation of Washington and the Eugene, Pittsburg Bluff, 

and Tunnel Point Formations of Oregon to the upper 

Refugian. He regards the Bastendorf [Bastendorff] 

Shale and Keasey Formation of Oregon as lower 

Refugian and believes that the Gries Ranch Formation of Washington also is probably lower Refugian. 

He notes that the molluscan assemblages of the 

Acila shumardi Zone of Schenck are definitely associated with upper Refugian foraminifers. These 

foraminifers are believed to have lived in deeper 

water, or at least cooler water, than those of the lower 

Refugian Turritella variata Zone of California (p. 152). 

To Kleinpell the foraminifers of the Refugian Stage 

suggest a cool-water habitat near the edge of the 

continental shelf, but not necessarily in a boreal province. Foraminifers characteristic of shallower water 

are numerous only locally, and there is a notable 

decrease of the open-sea types so abundant in the late 

Eocene. Southern foraminifers are scarcer on the 

whole than in the two directly overlying stages, 

suggesting that the climate was somewhat cooler in 

the middle Oligocene. 

1942. Weaver, C. E. 

Describes and illustrates all the known species of 

mollusks from the Pittsburg Bluff Formation and 

includes a checklist of all the species known to occur 

in the Tertiary formations of Oregon and 

Washington. 

1943. Forrest, L. C. 

Includes a chart of Oligocene formations in 

California and compares current age assignments 

with former age assignments (pl. 3). 

1943. Hanna, G. D., and Hertlein, L. G. 

Note the occurrence ofCallista pittsburgensis in the 

Kreyenhagen Shale [Eocene and Oligocene] in 

California. 

1944. Zimmerman, John, Jr. 

Regards the Tumey Sandstone, exposed in Fresno 

County, Calif., as late Eocene and early Oligocene, 

but believes that if the Acila shumardi zone is upper 

Refugian, the Tumey faunule is also. He correlates 

the Tumey with at least a part of the San Emigdio 

Formation, which also contains Acila shumardi. He 

notes that the Tumey Sandstone contains several 

mollusks characteristic of the Pittsburg Bluff 

Formation. 

1944. Allen, J. E., and Baldwin, E. M. 

Consider the Bastendorf[Bastendorff] Shale mostly 

latest Eocene but possibly in part early Oligocene. 

They report it consists predominantly of shale and is 

2,095 feet thick. 

They note that the Tunnel Point Sandstone is middle Oligocene, overlies the Bastendorf [Bastendorff] 

Shale with apparent conformity, consists mainly of 

sandstone, and is 800 feet thick. 

1944. Durham, J. W. 

Reports the occurrence of Acila shumardi in the 

Molopophorus stephensoni, M. gabbi, Turritella 

olympicensis, and T. porterensis Zones, which collectively make up the Gries Ranch, Pittsburg Bluff, 

and Lincoln [Lincoln Creek] Formations. He states 

that the Pittsburg Bluff fauna is restricted to the 

Molopophorus gabbi Zone and is characterized by 

Bruclarkia columbiana, Molopophorus dalli, Perse 

olympicensis quimpersensis, P. pittsburgensis, and 

Mactra pittsburgensis. 

1944. Keen, A.M., and Bentson, Herdis 

Show that a marked decrease in the total number of 

Tertiary molluscan species occurred in California 

during the Oligocene (fig. 3, p. 8). 

1945. Warren, W. C., Grivetti, R. M., and Norbisrath, 

Hans 

Report the Pittsburg Bluff Formation to be disconformably underlain by the Keasey Shale [late 

Eocene and early Oligocene] and disconformably 

overlain by beds of Blakeley age [late Oligocene or 

early Miocene]. The basal member of the Pittsburg 

Bluff Formation is a moderately indurated, massive, 

quartzose sandstone, marine at the type locality, but 

terrestrial on Pebble Creek. This basal member is at 

least 500 feet thick. It is overlain by a massive to 

poorly stratified, sandy tuffaceous shale member 
INTRODUCTION 7 

which includes numerous ash beds that are mostly 

less than 1 foot thick. The thickness of the Pittsburg 

Bluff Formation along the United Railway is about 

850 feet. 

Fossils at the type locality (USGS 15264) occur in 

the sandstone member and belong to the M olopophorus gabbi Zone, but the upper part of the shale 

member may belong to a slightly younger zone. The 

authors list 40 species of mollusks, identified by H. E. 

Vokes. 

1946. Warren, W. C., and Norbisrath, Hans 

Describe the lower part of the Pittsbu,rg Bluff 

Formation as composed of fine-grained marine 

sandstone containing numerous fossils in layers 

along the bedding and in calcareous concretions. 

These beds apparently pass upward into coarser 

massive sandstone which interfingers with 

crossbedded, nearshore, marine, and brackish-water 

sandstone. Higher in the section there are fewer 

molluscan fossils and more brackish-water beds 

containing plant remains. Near the top there are few 

fossils and many thick beds of tuffaceous material. 

The type locality, on the Nehalem River Highway 

near Pittsburg, displays marine fossiliferous beds and 

is near the base of the formation. The formation as a 

whole is characterized by a nearshore megafauna 

that is rich in the number of individuals of certain 

species. Representative mollusks are listed (p. 230). 

The rocks disconformably overlying the Pittsburg 

Bluff Formation are named the Scappoose Formation 

[late Oligocene and early Miocene] (p. 231). 

The authors regard the fauna of the Pittsburg Bluff 

Formation as similar to that of the Molopophorus 

gabbi Zone of Durham (1944, p. 112), but believe that 

the middle part of the Quimper Sandstone and the 

beds at Clatskanie, Oreg., correlated by Durham with 

the Pittsburg Bluff, are equivalent to the Gries Ranch 

Formation and therefore older. 

1946. Detling, M. R. 

Believes that the Bastendorf [Bastendorff] Shale is 

either Eocene or Oligocene and that it may have been 

deposited in warm or temperate shallow water near 

the shoreline. 

1947. Lowry, W. D. 

States that the shoreline of the Oligocene sea in 

northwestern Oregon almost paralleled the present 

coastline and was east of Eugene, Albany, and Silverton and west of Portland, Oreg. (p. 3). 

Believes that the coal that occurs in the Pittsburg 

Bluff Formation 2¥2 miles west of Scappoose and 1 

mile south of Deer Island, Oreg., indicates the 

shoreline was nearby (p. 6). 

1948. Vokes, H. E., and Snavely, P. D., Jr. 

Report that in the Eugene area the earliest middle 

Oligocene sediments were deposited in a restricted 

seaway north of the Eugene quadrangle. The continental deposits of the Fisher Formation had been 

laid down throughout this area, and the sea advanced 

over them toward the south. In the transgressing sea, 

the Eugene Formation was deposited in shallow 

offshore water. 

1948. Rau, W. W. 

Believes that all or part of the Porter Shale of 

northwestern Washington may be late Eocene, and 

possibly none of it of middle Oligocene age (p. 157). 

Reports that five species of foraminifers, and 20 

closely related forms found in the Porter Shale, also 

occur in the Tumey Formation [early and middle 

Oligocene], and that one foraminifer has also been 

found in the Keasey Formation [late Eocene and early 

Oligocene]. 

The Porter Shale was deposited offshore in a fairly 

shallow, temperate to warm sea. 

1952. Durham, J. W. 

Finds that the Stepof Bay fauna [Oligocene] of 

Alaska has subtropical or warm-temperate affinities. 

1953. Moore, R. C., and Vokes, H. E. 

Briefly consider in discussing the age of the Keasey 

Formation, the Pittsburg Bluff Formation, and 

compare the mollusks occurring in the crinoidbearing beds of the Keasey with those in the Pittsburg 

Bluff Formation. They show part of the Pittsburg 

Bluff Formation on an outcrop map of the area in 

which the crinoid beds occur. They report that the 

Keasey Formation includes the latest Eocene and 

early Oligocene and that the crinoid-bearing beds are 

probably early Oligocene. 

They believe that the Keasey Formation was deposited in relatively deep water, below effective wave 

action, but near the shoreline. The crinoid-bearing 

middle member of the Keasey was deposited in water 

ranging to a depth greater than 500 fathoms [914 m]. 

1953. Weaver, C. E. 

States that the Refugian is coeval with the 

((Keasey ," ((Lincoln," and ((Blakeley" Stages, in 

ascending order. He regards the San Ramon Formation [early Miocene(?)] as Oligocene and correlates it 

with the ((Blakeley" Stage. 

1956. Stewart, R. E. 

Considers the Toledo Formation of western Oregon 

late Eocene to middle Oligocene in age and assigns 

the Moody Shale Member to the late Eocene. He 

regards the Bastendorf [Bastendorff] Shale of 

southwestern Oregon as late Eocene and early 

Oligocene; the upper 700 feet are Oligocene (p. 59). 

1958. Brown, R. D., Jr., and Gower, H. D. 

Divide the Twin River Formation of Arnold and 

Hannibal (1913) in northwestern Washington into 
8 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

three members, which they believe, on the basis of 

fossil mollusks, foraminifers, and plant leaves, to be 

late Eocene to early Miocene (p. 2510). They correlate 

the Lincoln [Lincoln Creek] Formation of Weaver 

with the middle and upper members of the Twin River 

Formation. 

1960. Kanno, Saburo 

States that the mollusks Cyclocardia (Cyclocardia) 

hannibali andLucinoma columbiana, which occur in 

the Pittsburg Bluff Formation, also occur in the 

Ushikubitoge Formation [Oligocene] of central Japan. 

1961. MacNeil, F. S., Wolfe, J. A., Miller, D. J., and 

Hopkins, D. M. 

Show the Acila shumardi Zone as middle and late 

Oligocene, the Stepovak Series as early and middle 

Oligocene, and the Poul Creek Formation as middle 

Oligocene to early Miocene (on a correlation chart of 

Tertiary formations exposed in Alaska). 

They state that some stocks of the mollusks were of 

Asiatic origin and occur in older rocks in Alaska than 

in Oregon and California. 

1963. Snavely, P. D., Jr., and Wagner, H. C. 

Describe marine Oligocene rocks of western Oregon 

and Washington as consisting of massive tuffaceous 

siltstone and fine-grained sandstone with intercalated beds of pumiceous lapilli, tuff, and glauconite (p. 

16). They include a paleogeologic map showing the 

Oligocene coastline (fig. 13, p. 15). 

1964. Brabb, E. C. 

Subdivides the San Lorenzo Formation of the 

central California Coast Ranges into the Two Bar 

Shale Member [late Eocene] and the Rices Mudstone 

Member [late Eocene and Oligocene]. The foraminifers Uvigerina cocoaensis, ~~Planulina" haydoni, and 

Cibicides hodgei (p. 677) occur in the lower part of the 

Rices Mudstone Member. [These species are present 

in the Bastendorff Shale.] The type section of the 

Rices Mudstone Member contains the Pittsburg Bluff 

mollusks Litorhadia washingtonensis and Nemocardium lorenzanum (p. 677). 

He reports that many or all of the mollusks found by 

Arnold (1908) in the San Lorenzo Formation occur in 

the upper part of the Rices Mudstone Member or the 

Vaqueros Sandstone (p. 675). 

1964. Zullo, V. A., Kaar, R. F., Durham, J. W., and 

Allison, E. C. 

List the occurrence of36 taxa, representing 7 phyla, 

in the Keasey Formation, which they believe to have 

been deposited in water about 200 fathoms (350m) 

deep. They believe the undisturbed echinoids indicate 

either rapid live burial or a scarcity of scavengers and 

detritus feeders. 

1965. Burke, C. A. 

Reports that collections of Oligocene fossils from 

the Alaska Peninsula are characterized by Acila 

shumardi and resemble those of the Lincoln Creek 

Formation in Washington (p. 113--114). 

1965. MacNeil, F. S. 

Believes the Oligocene faunas of Alaska are predominantly of Asiatic origin and many Asiatic species 

appeared earlier in Alaska than in Oregon or 

California. 

[Mollusks that occur in the Pittsburg Bluff Formation are found in the Stepovak Formation, early 

and middle Oligocene.] 

1966. Oakeshott, G. B. 

Considers, on a correlation chart (fig. 3, opp. p. 36), 

the following marine formations of the California 

Coast Ranges to be at least in part middle Oligocene: 

Tumey Formation, ((Kirker" Sandstone, San Ramon, 

San Lorenzo, and Alegria Formations. 

1966. Dibblee, T. W., Jr. 

Reports that the Alegria Formation near Santa 

Barbara, Calif., contains Callista sp. cf. C. 

pittsburgensis andAcila shumardi, species that occur 

in the Pittsburg Bluff Formation. The entire fauna 

indicates an Oligocene (Refugian) age, as does the 

fauna from the Gaviota Formation. 

1967. Wolfe, J. A., and Hopkins, D. M. 

State that a sharp cooling took place during the 

middle Oligocene (p. 72, fig. 3), and that radiometric 

dates indicate this cooling took place within an interval no longer than 2 million years and possibly as 

short as 1 million years. 

1967. DeLise, K. C. 

Lists the following Pittsburg Bluff mollusk species 

as occurring in the upper sandstone unit of the San 

Emigdio Formation of California (p. 16): Acila 

shumardi, Bruclarkia columbianum?, and Polinices 

washingtonensis. [Also cites Molopophorus dalli, a 

species that seems in Oregon to be restricted to the 

early Oligocene.] 

1969. Hickman, C. J. S. 

Describes two new species that occur in both the 

Pittsburg Bluff Formation and the Eugene Formation 

[early and middle Oligocene]: Tellina aduncanasa 

and Neverita thomsonae. Seventeen species common 

to both the Eugene and Pittsburg Bluff Formations 

are described. 

She states that the Eugene Formation is early and 

middle Oligocene and contains a fauna of mixed 

Keasey and Pittsburg Bluff affinities. 

1969. Denton, G. H., and Armstrong, R. L. 

State that the Poul Creek Formation in southern 

Alaska is of late Oligocene or early Miocene age, is 

1,875 m thick, and consists of marine sediments deposited in a temperate or subtropical climate (p. 1137). 
INTRODUCTION 9 

1969. Fairchild, W. W., Wesendunk, P. R., and 

Weaver, D. W. 

Report a slight cooling throughout the area of the 

present California Coast Range during the time that 

the San Lorenzo Formation, of late Eocene to middle 

Oligocene age, was being deposited. 

1969. Snavely, P. D., Jr., MacLeod, N. S., and Rau, 

w.w. 

Refer the Oligocene siltstone of the Newport area, 

Oreg., informally called ~~siltstone of Alsea" and 

previously included in the upper Toledo Formation, to 

the upper Refugian and the Zemorrian Stages. 

[Mollusks indicate a middle Oligocene to late 

Oligocene or early Miocene age for this unit.] , 

1970b. Addicott, W. 0. 

Considers the Oligocene ~~Lincoln Stage" equivalent to the biozone of Acila shumardi, which is assigned to the Refugian Stage. He believes less than 10 

percent of the still-living genera from the Acila 

shumardi Zone of the San Emigdio Mountains, Calif., 

are tropical or subtropical. 

He believes the mollusks of the lower part of the 

~~Lincoln Stage" are marginally subtropical to warm 

temperate. 

He reports that more than half of the molluscan 

genera from the lower part of the ~~Lincoln Stage" 

today range northward into the temperate Oregonian 

molluscan province. He believes the late Oligocene 

Echinophoria rex Zone of Durham (1944) was probably warm temperate. 

He believes that the decreases in warm-water 

genera and taxonomic diversity show cooling during 

the middle Oligocene. 

1971. MacNeil, F. S. 

Reports that species of mollusks and closely related 

forms found! in the Pittsburg Bluff Formation are 

found in the Poul Creek Formation [middle Oligocene 

to early Miocene]. 

1972. Berggren, W. A. 

Considers the Refugian Stage late Eocene and the 

Zemorrian Stage Oligocene. 

1972. McKeel, D. R., and Lipps, J. H. 

Believe planktonic foraminifers and coccoliths 

from the middle part of the siltstone of Alsea, exposed 

along the north side of Alsea Bay, near Newport, 

Oreg., suggest a latest Eocene or earliest Oligocene 

age for this unit. 

1973. Addicott, W. 0. 

Reports thatBruclarkia columbiana (Anderson and 

Martin), a Pittsburg Bluff species, occurs in the 

Cymric Shale Member [Oligocene] of the Temblor 

Formation in California. Neverita thomsonae 

Hickman, Panopea ramonensis (Clark), and Dentalium laneensis Hickman, also Pittsburg Bluff 

species, occur in the Wygal Sandstone Member 

[Oligocene] of the Temblor Formation. 

He notes that Bruclarkia columbiana is restricted 

to the upper part of the Refugian Stage in California 

but is found in the middle and upper part in western 

Washington, which is equivalent to the Acila 

shumardi Zone and the ~~Lincoln Stage." He states 

that beds containing Bruclarkia columbiana can be 

traced into the lowermost part of Kleinpell's type 

Zemorrian section suggesting that the Refugian and 

Zemorrian Stages are in part coeval. 

1973. Jeletzky, J. A. 

Recognizes the post-late Eocene regional molluscan 

stages-Keasey (in part), Lincoln, Blakeley, and 

Clallam--of the Pacific northwest from southeastern 

Alaska to southwestern Oregon. Within this northern 

region of the Pacific coast, these zones persist through 

intertidal pebble conglomerate, grit, and sandstone to 

outer neritic or bathyal siltstone and shale. The 

southern molluscan faunas of the Pacific coast served 

as a basis for another regional sequence of molluscan 

stages-Lorenzian, V aquerosian, Temblorian, Montereyan, and Margaritan. He suggests that the post-late 

Eocene molluscan and foraminiferal faunas of western 

North America were controlled by water temperature. 

He believes that the northern set of Tertiary 

molluscan stages and zones, when used within the 

northern region, are equal or superior to the regional 

foraminiferal zones and stages. 

He correlates the Lincoln molluscan stage of the 

northern Pacific coast with the upper Refugian 

foraminiferal stage, and places part or all of the 

Keasey molluscan stage of the northern region in the 

uppermost Eocene. 

1974. Watkins, Rodney 

Names four communities of mega-invertebrates in 

the Kreyenhagen Formation [Eocene and Oligocene] 

in the Arroyo Ciervo area, Calif., that he considers 

mappable ecologic units. Two are named for 

characteristic Pittsburg Bluff species, the ~~Macrocallista pittsburgensis Community," which consists 

largely of M. pittsburgensis, and the ~~Nuculana 

washingtonensis Community," which consists almost 

entirely of N. washingtonensis and associated M. 

pittsburgensis. The Pittsburg Bluff Formation of 

Oregon is in a ~~Northern Province" with 17 or less 

percent of warm-water genera. The fauna probably 

lived in a littoral or very shallow sublittoral environment. Macrocallista pittsburgensis is eurytropic 

and maintains large populations in several environments. 

1975. Snavely, P. D., Jr., MacLeod, N.S., Rau, W. W., 

Addicott, W. 0., Pearl, J. E., and Quinterno, P. J. 
10 OLIGOCENE MARINE MOLLUSKS FROM THE PI'ITSBURG BLUFF FORMATION IN OREGON 

Name and describe the Alsea Formation [early to 

late Oligocene], exposed along the shore of Alsea Bay, 

Oreg., and correlate it with the Eugene and Pittsburg 

Bluff Formations and the upper part of the Keasey 

Formation in Oregon, and with the Lincoln Creek and 

Blakeley Formations and the middle and upper 

members of the Twin River Formation in 

Washington. 

ACKNOWLEDGMENTS 

I am indebted to my colleagues Warren 0. Addicott, 

U.S. Geological Survey; W. P. Woodring, U.S. National 

Museum; F. Stearns MacNeil, Fort Myers, Fla.; Arnold 

Ross and George E. Radwin, San Diego Natural History 

Museum, for helpful discussions, advice, and assistance. 

The late Leo G. Hertlein, California Academy of Sciences, provided me with type specimens and information pertinent to them and was helpful in many other 

matters. Joseph H. Peck, University of California, and 

Horace G. Richards, Academy of Natural Sciences of 

Philadelphia, kindly made available to me type fossils 

that I needed. To Kenji Sakamoto, U.S. Geological 

Survey, I am especially indebted for his patience and 

care in taking the photographs that illustrate this 

report. 

The San Diego Natural History Museum kindly made 

office space available to me, and Mrs. Azalea Gorby, 

Librarian, obtained needed references. Anthony 

D' Attilio graciously agreed to draw the suture sketch of 

Turritella pittsburgensis, n. sp. To the entire staff of the 

museum I would like to extend my thanks for their 

kindness and willingness to offer assistance when 

needed. 

Kenneth W. Ciriacks, Amoco Production Co., Tulsa, 

Okla., provided me with information relating to the 

occurrence of Pittsburg Bluff species in Alaska. The 

release of this information was granted by Amoco 

Production Co., Denver Division, Colo. 

The Crown Zellerbach Corp., Vernonia, Oreg., kindly 

made available a map of the corporation's tree farm. 

I am indebted to the late Frank C. Calkins, formerly a 

geologist in the U.S. Geological Survey, who at the age 

of95 increased the readability of the nontechnical parts 

of my manuscript. 

PITTSBURG BLUFF FORMATION 

STRATIGRAPHY 

GENERAL FEATURES AND GEOGRAPHIC DISTRIBUTION 

The Pittsburg Bluff Formation is confined to northwestern Oregon (figs. 1-3). Most of its exposures are in 

the Vernonia 15-minute quadrangle and in the northwestern quarter of the Forest Grove 15-minute quadrangle, but a few exposures of it, containing fossils, are 

found in the Cathlamet and Svenson 15-minute quadrangles. The formation is characterized by gentle 

L ~ ,_--/' ',--6 ~____, \ ~------Cb Astoria '1--.... / ', i'.;,. lcoLUMBIA'-<~6 CLATSOP i COUNTY \ ~ 

couNTY i itlL. ',\ 

-~- ~ '~-~~~[~- iftilli1! '-[.;;: -t <\'. 

TILLAMOOK "----.. \.., <r-1t-...__1'!er ,.----'WASHINGTON"-, M~:tc~-, __ _ / COUNTY \.. 0 °UN/y <-----:.__ , _ _,!'~t!_a~d ___ _ 

! '\_ r'-J I L.J 

j YAMHILL (1~..1-~ CLACKAMAS 

~----- COUNTY , I COUNTY 

I / J I .... l 

~------------( "-, ----- ( "---, 

~JoSalem \, 

POLK COUNTY 1

/ '-~--

I_ MARION COUNTY 

r) ,../-........._---.. Lc __________ r~, ~/ -~---'\, I \ ~ ..... 

I r~\ Ll NCO L N i Corvallis 0-' 

COUNTY f ~~~~~~ J Ll NN COUNTY 

__ J I 

! ; ,,--.J \ 

----='-------------\ --~ \ ____ 5~ '...___'-- ____ /---

0 Eugene 

LANE COUNTY 

-.,_ __ ,-"/--"--i:__ 

'--'---

L----, 

DOUGLAS 

COUNTY 

I 

0 10 20 MILES 

I I I 0 10 20 Kl LOMETRES 

FIGURE L-Location of area of study at Vernonia, Oreg. 

northwest-trending folds superimposed on an eastward 

regional dip of about 5°. It is underlain by the Keasey 

Formation (late Eocene and early Oligocene) and overlain by the Scappoose Formation (late Oligocene and 

early Miocene) (fig. 4). 

The precise stratigraphic assignment of some fossil 

localities within the Pittsburg Bluff Formation is uncertain owing to discontinuity in outcrops. Local structure compounds the stratigraphic uncertainty. Southeastward from the type locality, for example, many of 

the richest collections, all of approximately the same 
PITTSBURG BLUFF FORMATION 11 

FIGURE 2.-Type locality of Pittsburg Bluff Formation 1 km northeast 

of Pittsburg, Oreg. The calcite-cemented concretions are aligned 

with a bed rich in molluscan fossils. Trough-shaped sedimentary 

structure (at top) may have formed when sand slid downward on 

submarine slope. 

age, were taken at widely separated localities in a long 

anticlinal valley drained by the East Fork of the 

Nehalem River. 

TYPE LOCALITY 

The type locality, which exposes the lower part of the 

Pittsburg Bluff Formation, but not quite the base, is a 

roadcut on Oregon State Highway 4 7, 1 km northeast of 

Pittsburg, where the exposed section is about 10 m 

thick. The typical sequence in this cut consists of a 

2-m-thick layer of sandstone showing prominent 

bioturbation overlain by a 10-cm-thick fossiliferous 

limy layer or a layer of concretions. These are overlain 

by a laminated sandstone with laminae about 5 mm 

thick, which becomes bioturbate 1m above its base. The 

entire section is highly fossiliferous, but shells are most 

abundant in the limy layers. 

TYPE AREA 

The type area of the Pittsburg Formation extends 

along the Nehalem River between Pittsburg and Mist, 

Oreg. The Pittsburg Bluff Formation is about 200 m 

thick. The olive-gray siltstone of the Keasey Formation 

(late Eocene and early Oligocene) is conformably overlain by 30 m of massive olive-gray fine-grained 

sandstone (fig. 5). The sandstone is characterized by 

fossiliferous concretions (fig. 2), by trough-shaped 

prisms possibly resulting from internal shear during 

aggradation, and locally by siltstone rip-up clasts (fig. 

6). Thin-bedded light-olive-gray fine-grained sandstone 

and siltstone with foreset beds and local coal beds near 

the top occupy the next 70 m (fig. 4). The uppermost 100 

m consists of massive friable olive-gray fine-grained 

sandstone. The Pittsburg Bluff Formation is overlain by 

dusky-yellow fine-grained tuffaceous sandstone of the 

Scappoose Formation. Locally the contact is marked by 

a cobble conglomerate. 

A faunal break occurs approximately in the middle of 

the Pittsburg Bluff Formation. This break possibly may 

be only an apparent one, and may merely reflect the 

facts that the lower part of the formation is generally 

more fossiliferous than the upper parts and that it includes the easily accessible classic exposure on State 

Highway 47. Nonetheless, a difference in the molluscan 

fauna exists and may reflect a real change in the composition of the Pittsburg Bluff fauna. At one locality, 

USGS 15588, at the base of the upper part of the formation, species elsewhere confined to the upper or lower 

parts occur together. 

The following mollusks occur only in the lower 100m 

of the Pittsburg Bluff Formation (excluding USGS locality 15588). 

Gastropods 

Opalia (Dentiscala?) hertleini, n. sp. 

Crepidula pileum (Gabb) 

Polinices washingtonensis (Weaver) 

Sinum aff. S. obliquum (Gabb) 

Priscofusus stewarti (Tegland) 

Perse pittsburgensis vernoniensis, n. subsp. 

Taranis columbiana (Anderson and Martin) 

Spirotropis kincaidi (Weaver) 

Odostomia winlockiana Effinger 

Pelecypod 

Crenella porterensis Weaver 

The following mollusks occur only in the upper 100m 

of the Pittsburg Bluff Formation (excluding USGS locality 15588). 

Gastropods 

Architectonica blanda Dall 

Aforia campbelli Durham 

Pelecypods 

Cyclocardia (Cyclocardia) cf. C. hannibali (Clark) 

Spisula (Mactromeris?) veneriformis Clark 

The following mollusks occur throughout the entire 

thickness of the Pittsburg Bluff Formation. 

Gastropods 

Turritella pittsburgensis, n.sp. 

Cryptonatica pittsburgensis, n. sp. 

Neverita (Glossaulax) thomsonae Hickman 

Eosiphonalia oregonensis (Dall) 

Bruclarkia columbiana (Anderson and Martin) 

Molopophorus gabbi Dall 

Perse pittsburgensis Durham 

Suavodrillia winlockensis (Effinger) 

Acteon chehalisensis (Weaver) 

Scaphander stewarti Durham 
12 

45'55' 

45'50' 

45' 45' 

OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

EXPLANATION 

[EJ . 

~ • Astoria Formation 

~ 

~ B . 

Columbia River Group ;... 

[ill] ~ 

< 

1= 

Scappoose Formation ~ 

~ p;.) 

. t. -tpb·. ·I E-< ~ 

~ 

~ 

g Pittsburg Bluff Formation 

~ 

~ • 

~ 

~ ~ Keasey Formation "' 

Contact 

Anticline 

Showing trace of axial plane 

Syncline 

Showing trace of axial plane 

Strike and dip of beds 

X :.;328~~ 

Fossil locality 

Measured section 

0 2 MILES 

I I 

0 2 KILOMETRES 

FIGURE 3.-Geologic sketch map of the Vernonia area, northwestern Oregon, showing fossil localities and location of 

measured sections. 
PITTSBURG BLUFF FORMATION 

N 

Coal Creek 

EXPLANATION 

Siltstone 

Tuffaceous 

sandstone 

Sandstone, 

with concretions 

Type locality of Pittsburg Bluff 

Formation lies between Moran 

Farm and Pittsburg 

(Diller, 1896) 

Moran Farm t 

Pittsburg 

oOO 

aoo Ooo 

00 D 

Cobble 

conglomerate 

Coal 

M3 8 71 

Fossil Locality 

Vernonia 

~l~~""" 

M3871 

Divide 

.~ ... M3860 Pittsburg Bluff Formation 

Keasey Formation 

0 2 3 4 6 MILES 

I 

I I 

I I 0 2 3 4 5 6 8 9 10 Kl LOMETRES 

Scappoose Formation 

Pittsburg Bluff Formation 

Tophill 

···-···~··!t 

- ···- ···-· ···-···- ··· :-:-:-:·.·.·.--:-:-:·.·.:-:-:-:· 

................ 

~.-::...:....:....:.:::.:....:..:..: 

···~ ··· -··· 

·::::-.:_:;:::::_:_:_~-..: . 

···-···-··· 

;;;: t :::K:· -···-···-

···-···-··· 

FEET 

300 

200 

100 

0 

METRES 

100 

50 

0 

s 

FIGURE 4.- Measured sections of the Pittsburg Bluff and adjacent formations, Vernonia area, Oregon. See figure 3 for locations. 

13 

FIGURE 5.-Contact between siltstone of the Keasey Formation (below) and sandstone of the Pittsburg Bluff Formation (above), in 

roadcut along logging road 1 km southeast of Pittsburg, Oreg. 

FIGURE 6.-Siltstone rip-up clasts in Pittsburg Bluff Formation in 

roadcut along logging road 2 km southeast of Pittsburg, Oreg. 
14 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

Scaphophod 

Dentalium (Fissidentalium?) laneensis Hickman 

Pelecypods 

Nucula (Leionucula) vokesi, n. sp. 

Acila (Truncacila) shumardi (Dall) 

Litorhadia washingtonensis (Weaver) 

Yoldia (Kalayoldia) oregona (Shumard) 

Mytilus cf. M. snohomishensis Weaver 

Lucinoma columbiana (Clark and Arnold) 

Felaniella (Felaniella) snavelyi, n. sp. 

Nemocardium (Keenaea) lorenzanum (Arnold) 

Spisula (Mactromeris) pittsburgensis Clark 

Tellina (Eurytellina) aduncanasa Hickman 

Tellina? pittsburgensis Clark 

Solen townsendensis Clark 

Solena (Eosolen) eugenensis (Clark) 

Panopea snohomishensis Clark 

Panopea ramonensis Clark 

Cochlodesma bainbridgensis Clark 

Thracia (Thracia) condoni Dall 

The pelecypods do not indicate any striking faunal 

break, but the gastropods do; 9 of 23 species are restricted to the lower part of the Pittsburg Bluff Formation. This break suggests, therefore, that two faunal 

zones may be present in the Pittsburg Bluff Formation 

in its type area, one in the lower 100 m and one in the 

upper. 

CHECKLIST OF PITTSBURG BLUFF SPECIES 

Exposures of the Pittsburg Bluff Formation are 

found in an area of about 150 km 2 ; they indicate a 

maximum thickness of approximately 200 m. As 

paleontologists and geologists have been collecting fossil mollusks from the formation since the early 1900's, it 

is reasonable to assume that their collections contain 

specimens of most of the animals with preserved hard 

parts that lived in the middle Oligocene sea of that part 

of northwestern Oregon. A checklist of the Pittsburg 

Bluff mollusks is given in table 1. 

As most of the collections studied were made by other 

workers and had already been prepared, it was not 

possible to determine if all the specimens were collected 

from one stratigraphic interval, nor if each collection 

represented all the specimens available. Parts of the 

U.S. Geological Survey collections made by H. E. Vokes 

and others in the early 1940's had not been prepared. 

For these and my own collections, abundance could be 

accurately noted, and it was noted during my own 

collecting in the field. 

The number of specimens representing a species in a 

collection of fossils is not necessarily related to the 

abundance of that species at a given fossil locality. If a 

species is easily removed from the enclosing rock, as are 

many of the naticids and also some pelecypods such as 

Acila, it is apt to be collected in large numbers. If one 

attempts to remove a fragile valve of a pelecypod from 

its matrix in the field, it is likely to break up into small 

pieces which may or may not be brought back with the 

collection. If a genus, such as Turritella, Liracassis, or 

Acila, is known to be of special value for age determination, or is uniquely sculptured, the collector is likely 

to make a special search for it, and to exercise great care 

in removing it from the enclosing rock. 

Even when a geologist is trying to collect a complete 

assemblage, he may fail to do so unless he collects everything he finds, for it is often difficult to distinguish 

similar species in the field. The abundance and variety 

of species in a collection may depend on the purpose for 

which the collection was made; fewer specimens are 

required for a determination of age than for a thorough 

study of a fauna. 

In an attempt to estimate the relative abundance of 

species in the Pittsburg Bluff Formation as exposed in 

the area dealt with here, I have noted the number of 

specimens of each observed in the field and in collections 

prepared from slabs of rocks. For some species, the 

results thus obtained may be far from accurate, but no 

better method seems to be available. I have not given 

numbers of specimens for each locality but have adopted 

the terminology that Smith and Gordon (1948) used in 

reporting the abundance of species ofliving mollusks in 

Monterey Bay, Calif., and applied it to the fauna as a 

whole: 

Abundant: found nearly everywhere, usually more 

than 20 specimens. 

Common: usually found in moderate abundance (10 

to 20 specimens). 

Scarce: found at several localities, usually singly or 

only a few together 

Rare: A total of only a few specimens found by me or 

known to have been collected by others. 

The following list gives the relative abundance of 

species found in the Pittsburg Bluff Formation: 

Gastropods 

Abundant 

Cryptonatica pittsburgensis, n. sp. 

Polinices washingtonensis (Weaver) 

Neverita (Glossaulax) thomsonae Hickman 

Bruclarkia columbiana (Anderson and Martin) 

Molopophorus gabbi Dall 

Perse pittsburgensis Durham 

Common 

Perse pittsburgensis vernoniensis, n. subsp. 

Taranis columbiana (Anderson and Martin) 

Spirotropis kincaidi (Weaver) 

Suavodrillia winlockensis (Effinger) 

Scaphander stewarti Durham 
TABLE 1.-Checklist of species at U.S. Geological Survey localities in the Pittsburg Bluff Formation arranged in approximate stratigraphic order 

Upper part of Pittsburg Bluff Formation 

Species 

g lO I ;e lO I 0 t-1..-< ~ I~ lO ItO ...-< I~ lO I lO ~I M ~I g:; ~ I~ lO I~ ~ I lO ~I M ~I lO ~I~ M 1·~ ~ 

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

Gastropods: 

Unidentified trochid? ______________________ _ 

Architectonica blanda Dall ____________ _ Turritella pittsburgensis, n. sp. ______________ I X 

Opalia (Dentiscala?) hertleini, n. sp. _________ _ Crepidula pileum (Gabb) ___________________ _ 

Cryptonatica pittsburgensis, n. sp. ___________ _ Polinices washingtonensis (Weaver) _________ _ 

Neverita (Glossaulaxl thomsonae Hickman_ Sinum aff. S. obliquum (Gabbi __________ _ Eosiphonalia oregonensis (DallJ _____________ _ 

Bruclarkia columbiana (Anderson and Martini 

Molopophorus gabbi Dall -------------------- Priscofusus stewarti (Teglandi _______________ _ Perse pittsburgensis Durham _______________ _ 

Perse pittsburgensis vernoniensis, n. subsp. ___ _ Aforia campbelli Durham ___________________ _ 

Taranis columbiana (Anderson and Martini Spirotropis kincaidi (Weaver) _______________ _ 

Suavodriliia winlockensis !Effinger! __________ I x 

Odostomia winlockiana Effinger _____________ _ Acteon chehalisensis (Weaver) _______________ _ Acteon? n. sp.? ____________________ _ 

Scaphander stewarti Durham ______________ _ 

Scaphopod: 

Dentalium (Fissidentalium?) laneensis Hickman I x 

Pelecypods: 

Nucula (Leionuculal vokesi, n. sp. ___________ _ 

Acila (Truncacila) shumardi (DallJ __________ I X 

Litorhadia washingtonensis (Weaver) ________ x Yoldia (Ka.layoldia) oregona (Shumard! _____ _ Mytilus of. M. snohomishensis Weaver _______ _ Crenella porterensis Weaver _______________ _ 

Cyclocardia (Cyclocardia) cf. C. hannibali (Clark) _________________________________ _ 

Lucinoma columbiana (Clark and Arnoldi ___ _ Felaniella (Felaniella) snavelyi, n. sp. _______ _ 

Nemocardium (Keenae) lorenzanum <Arnoldi--~ x Pitar (Pitar) dalli <Weaver) ------------------ __ Callista (Macrocallista) pittsburgensis Dall____ x Spisula iMactromeris) pittsburgensis Clark ___ _ Spisula (Mactromeris?i veneriformis Clark ___ _ ?Ervilia oregonensis Dall ___________________ _ 

Tellina (Eurytellinal aduncanasa Hickman ___ _ Tellina? pittsburgensis Clark ________________ 1 x Solen townsendensis Clark _________________ _ 

Solen a iEosolen) eugenensis (Clarki _________ _ 

Panopea snohomishensis Clark Panopea ramonensis Clark _________________ _ 

Cochlodesma bainbridgensis Clark Thracia (Thracia) condoni Dall _____________ _ 

Cephalopod: 

Aturia angustata (Conrad) 

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 

~I~ 

X 

X 

--, X 

X 

X 

X 

X 

X 

X 

X 

X 

XIX 

X 

X IX 

X 

X 

X 

X 

XIX 

X 

X 

XIX 

X 

X 

X 

XIX 

X X 

X 

X 

X 

X 

X 

X 

X 

X 

X I I X 

X 

X 

X I cf. I X 

cf. 

x I cf.l x X X 

X 

X 

X 

X 

X 

X 

X 

X I __ I X 

X 

X 

X 

X 

X 

X 

XIX 

Lower part of Pittsburg Bluff Formation 

~1~1 001~1~1~1~1 00 ~ 00 00 00 00 ...-< 00 ~ 1~1° 00 ...-< 

lO M lO M M ~ M lO ~ ~ 

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

..-<IOOI~I~I<C>I~ ~ r- r.L) 00 cv:l CCl ~ ~ M M lO lO 

~ ~ ~ ~ ~ ~ 

X 

X 

X 

X 

X I X I X X X 

X X 

X X 

X I X X 

X X 

X X 

cf.l X X 

X X X 

X 1-- I X X X X 

X 

X I X 

X I~ X 

X I X I X 

X 

X I X I X X X X 

X 

X 

X I X I X X X X 

X 

X 

X I X 

~I X I cl. 

XIX IX X X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X I X 

X 

X 

X I X 

X I X 

X 

X 

XIX 

X cf. I X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X I X I __ I X 

X 

~1-x-1-x-1~ 

X I -X I X I_ X I X 

X 

x ~--~ cf. 

X I X ~ I == == I ~ 

X X 

X I X I __ I X 

X 

xl~l-~lxl~ X 

X _ X 

~ ~--~ X 

X I X X --I X X X X __ X 

X I cf. X cf. 

x_, 

X X I cf. 

X 

X 

X I-- I X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

~,~,~~~,~,~,~,~,~ ~ ...-< ~ ~ <!:> t- <!:> M ~ 

~ ~ ~ ~ ~ ~ ~ ~ ~ 

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 

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 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

~ t-

~ 

X 

X 

::s 

~ r.n 

td 

c: 

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td 

t""' 

c: 

l-%j 

l-%j 

l-%j 

0 

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z 

1--L 

01 
16 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

Scarce 

Turritella pittsburgensis, n. sp. 

Eosiphonalia oregonensis (Dall) 

Priscofusus stewarti (Tegland) 

Acteon chehalisensis (Weaver) 

Rare 

Architectonica blanda Dall 

Opalia (Dentiscala?) hertleini, n. sp. 

Crepidula pileum (Gabb) 

Sinum aff. S. obliquum (Gabb) 

Aforia clallamensis wardi (Tegland) 

Odostomia winlockiana Effinger 

Scaphopod 

Common 

Dentalium (Fissidentalium?) laneensis Hickman 

Cephalopod 

Rare 

Aturia angustata (Conrad) 

Pelecypods 

Abundant 

Acila (Truncacila) shumardi (Dall) 

Litorhadia washingtonensis (Weaver) 

Callista (Macrocallista) pittsburgensis Dall 

Spisula (Mactromeris) pittsburgensis Clark 

Common 

Yoldia (Kalayoldia) oregona (Shumard) 

Felaniella (Felaniella) snavelyi, n. sp. 

Tellina (Eurytellina) aduncanasa Hickman 

Tellina pittsburgensis Clark 

Solen townsendensis Clark 

Solena (Eosolen) eugenensis (Clark) 

Panopea ramonensis Clark 

Thracia (Thracia) condoni Dall 

Scarce 

Nucula (Leionucula) vokesi, n. sp. 

Lucinoma columbiana (Clark and Arnold) 

Nemocardium (Keenaea) lorenzanum (Arnold) 

Pitar (Pitar) dalli (Weaver) 

Spisula (Mactromeris?) veneriformis Clark 

Panopea snohomishensis Clark 

Rare 

Cochlodesma bainbridgensis Clark 

Mytilus cf. M. snohomishensis Weaver 

Crenella porterensis Weaver 

Cyclocardia (Cyclocardia) cf. C. hannibali (Clark) 

?Ervilia oregonensis Dall 

ECOLOGY 

The Pittsburg Bluff Formation contains 43 identified 

genera of mollusks represented by 48 species, almost 

equally divided between pelecypods and gastropods and 

including one scaphopod and one cephalopod. Five of the 

gastropod genera are extinct: Eosiphonalia, Molopophorus, Bruclarkia, Perse, andPriscofusus, and three 

are locally extinct: Architectonica, Sinum, and Turritella. The pelecypod subgenus Eosolen is apparently 

restricted to the Eocene and Oligocene, and so is 

Litorhadia, which some authors classify as a subgenus 

of Nuculana. 

Thirteen of the total of 48 species are so abundant that 

almost any persistent collector would find them. 

Fourteen species are so rare that only one to five 

specimens of each have been found, presumably as the 

result of exhaustive collecting. The remaining 21 

species are represented, on the average, by about 20 

specimens each and may be assumed to constitute an 

important part of the fauna. A striking characteristic of 

the Pittsburg Bluff fauna is that an enormous number o~ 

fossils of a few species are tightly packed in the calcareous concretions and lenses within the formation. 

These are Callista (Macrocallista) pittsburgensis, Acila 

(Truncacila) shumardi, Molopophourus gabbi, Perse 

pittsburgensis, and the four naticid species that the 

formation contains. 

The pelecypods, with the exception of two small 

mytilids represented only by incomplete shells, are 

characteristic of an infauna (Thorson, 1957) that lived 

buried or burrowing in muddy sand on the sea bottom. 

Of the gastropods, all butCrepidula (represented by one 

well-preserved and three poorly preserved specimens) 

lived on or within the sediment of the sea floor. Rare or 

absent are forms that lived only on rocky shores or on an 

open sandy beach. Several of the genera that are particularly abundant in the fauna-for examplePolinices 

and Neverita-are known to be voracious feeders on 

clams (Hedgpeth and Hinton, 1961; Keen, 1971). 

Gastropods of the extinct genera Eosiphonalia, 

Bruclarkia, Perse, and Molopophorus, which lack the 

round aperture usually possessed by herbivorous snails, 

have long siphonal canals, indicating that they may 

have been detritus feeders or carnivores, preying upon 

clams; their familial assignments, if correct, imply that 

they were carnivores. The drill holes found in some 

pelecypod valves are straight sided, similar to the holes 

made by the Muricacea, none of which are known from 

the Pittsburg Bluff Formation, unless one of these 

extinct genera is missassigned. The formation also 

contains Turritella, which is known to live buried just 

beneath the sea floor and to feed upon detritus; Opalia, 

which is a carnivorous genus, with some species known 

to feed upon sea anemones and corals (Keen, 1971); and 

Odostomia, which is known to be parasitic upon other 

mollusks such as Ostrea, Pecten, and Crepidula, and 

upon polychaete worms (Keen, 1971). The only 

scaphopod represented is Dentalium, which lives buried 

under a thin layer of sediment on the sea floor (Keen, 

1963), and the only cephalopod is Aturia, which 

presumably inhabited moderately shallow water and 
PITTSBURG BLUFF FORMATION 17 

was carnivorous, perhaps feeding on decapod crustaceans (Miller, 1947, p. 13) or mollusks. 

The Pittsburg Bluff molluscan fauna contains none of 

the rock dwellers of the littoral zone with the possible 

exception of Mytilus, and no snails that are known to be 

herbivorous. None of the mollusks found in the formation, except the turrids, are considered indicative of 

deep water. No remains of echinoderms or crabs have 

been found, and foraminifers are represented by two 

poorly preserved globigerinids. Some fish remains have 

been found; the teeth identified are of sharks and rays. 

Welton (1972, p. 168) makes the following statement 

concerning the shark teeth: 

***the lower sections of the Pittsburg Bluff Formation yield 

numerous teeth of a small squalid shark Centroscymnus and not 

uncommonly teeth of Raja, Squatina, Odontaspis, Squalus, Pristiophorus, and Notorhynchus. These genera, plus several additional 

forms, collectively constitute the most diverse assemblage yet known 

from the middle Oligocene of Oregon. 

Otoliths from USGS 15310, in the middle part of the 

Pittsburg Bluff Formation, were identified by John E. 

Fitch, California Department of Fish and Game, as 

belonging to the families Congridae (conger eels) and 

Macrouridae (rat tails), both bottom-dwelling families 

that typically inhabit moderate (200 m) to great depths 

(500 m), and, although found in all oceans of the world, 

are least common in tropical seas (John E. Fitch, written communs., May 23, 1973, and June 18, 1973). 

From the preserved molluscan fauna, a picture 

emerges of an infaunal community of filter feeders, 

detritus feeders, and carnivores living on or within the 

sediment of the sea floor. 

The table below (table 2, compiled from Abbott, 1954; 

TABLE 2.-Holocene genera in the Pittsburg Bluff Formation and their 

preferred bottom sediment and water depth 

Genera Bottom sediment Depth of water 

Gastropods 

Architectonica ____________ Common in sand and Tidefiats to 60 m. 

sand-mud bottom. 

Turitella __________________ Soft bottom, sand or mud. Subtidal to 180m. 

Opalia (Dentiscala) ________ At base of sea anemones, 

under kelp. 

Crepidula ________________ Rock or shell. 

Cryptonatica ______________ Sand. 

Polinices (Polinices) ________ Bay sand fiats, mud fiats, 

clay. 

Neuerita (Glossaulax) ______ Sand bars, bay sand fiats. 

Sinum ____________________ Sand or mud fiats 

among small stones. 

Usually less than 15 but may 

be as much as 90 m. 

Intertidal to 160 m. 

Intertidal to 1,600 m. 

Intertidal to 2,500 m. 

Intertidal to 45 m. 

Intertidal to 45 m. 

Aforia _________ __________ _ ________________________ 60 to 2,500 m. 

Bipolar; descends into deep 

equatorial waters for requisite bottom temperature. 

Taranis __________________ _ _________________________ 180 to 750 m. 

Spirotropis ________________ _ _________________________ 730 to 3,650 m. 

Odostomia ________________ Parasitic on mollusks; Intertidal to 640 m. 

common near eelgrass 

roots. 

Acteon ____________________ Sand, bay-mud fiats. Intertidal to 75 m. 

Scaphander ______________ _ _________________________ 20 to 5,200 m. 

TABLE 2.-Holocene genera in the Pittsburg Bluff Formation and their 

preferred bottom sediment and water depth-Continued 

Genera Bottom sediment Depth of water 

Scaphopod 

Dentalium (Fissidentalium) -------------------------- 7 to 1,200 m. 

Pelecypods 

Nucula (Leionucula) ______ Clay, sand. 

Acila (Truncacila.) ________ Mud, fine sand, shell. 

Yoldia (Kalayoldia) ________ Sand. 

Mytilus __________________ Rock. 

20 to 1,800 m. 

10 to 1,300 m. 

Intertidal to 1,800 m. 

Intertidal to 50 m or 

perhaps more. 

Crenella __________________ -------------------------- 2 to 450 m. 

Cyclocardia ________________ Mud. 20 to 1,800 m. 

Lucinoma ________________ Sand. Intertidal to 540 m. 

Felaniella ________________ Sand or mud, under rocks, Intertidal to 75 m. 

usually in nest of 

agglutinated rubble; 

intertidal sand-beach and 

sand flats; nearshore 

sand and sand-mud. 

Nemocardium (Keenaea)_ ___ Outer shelf, sand bottom. 20 to 140m. 

Pitar _____________________ Coarse sand; intertidal Intertidal to 180m. 

sand-beach and sand 

flats; nearshore sand 

and sand-mud. 

Callista (Macrocallista) ____ Fine sand. 

Spisula (Mactromeris)_ _____ Sand of exposed beaches; 

fine sand or firm sandy 

mud of bays, sloughs, or 

estuaries; fine sand or 

sandy mud of protected 

open coast. 

Common in shallow water; 

not uncommonly washed 

ashore after storms. 

Intertidal to 45 m. 

Ervilia ____________________ _ _________________________ Just offshore to 90 m. 

Tellina (Eurytellina) ______ Sand or mud; coarse, Intertidal to 140m. 

shifting sand near 

entrances to bays, 

lagoons, or estuaries; 

sand or mud in bays; 

intertidal sand-beach 

and sand fiats; nearshore 

sand and sand-mud; 

outer shelf, sand. 

Solen ____________________ Sandy mud of sheltered Intertidal to 75 m. 

bays, sloughs, or 

estuaries; sandy 

beaches, coves. 

Panopea _________________ Sandy mud of bays, 

sloughs, or estuaries 

buried about 1 m. 

Intertidal to possibly subtidal. 

Cochlodesma ______________ _ _________________________ 20 to 90 m. 

Thracia __________________ Mud, rubble-reef, rock Intertidal to 140m, nestling. 

cavities, sponge beds. 

Berry, 1954; Burch, 1944-46; Eyerdam, 1960; Fitch, 

1953; Hedgpeth and Hinton, 1961; Javidpour, 1973; 

Keen, 1963, 1971;McLean, 1969;0ldroyd, 1924;Packard, 1918; and Parker, 1963) shows the known depth of 

water and bottom sediment inhabited by Holocene 

genera represented in the Pittsburg Bluff fauna. 

Although none of the Pittsburg Bluff molluscan fos~ 

sils have been found in life position, many pelecypods 

are preserved as articulated specimens; this fact 

suggests that they were transported rapidly or a relatively short distance. Fragments of shells make up 50 

percent of the matrix, and these fragments represent 
18 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

the same species of mollusks that are found as entire 

. specimens. All the species found together did not 

necessarily live together in identical environments or at 

the same depth. Three habitats are suggested-one of 

deep water, perhaps at least 100 m; one of moderately 

shallow water, perhaps about 20 m; and one of shallow, 

nearshore water, less than 20 and some of it intertidal. 

None of the genera lived in high-energy coastal 

environments. I 

The following genera and subgenera are considered 

indicative of sand or mud flats, bars, or shallow 

protected bays: 

Gastropods 

Opalia (Dentiscala) 

Polinices (Polinices) 

Neve rita 

Sinum 

Acteon 

Pelecypods 

Felaniella 

Pitar 

Spisula (Mactromeris) 

Tellina (Eurytellina) 

Solen 

Panopea 

Genera and subgenera that usually occur together at 

depths of 20m or more, but not as a rule intertidally, 

include the following: 

Gastropods 

Turritella 

Scaphander 

Scaphopod 

Dentalium 

(Fissidentalium ?) 

Pelecypods 

Nucula (Leionucula) 

Acila (Truncacila) 

Yoldia (Kalayoldia) 

Crenella 

Cyclocardia 

Nemocardium (Keenaea) 

Ervilia 

Cochlodesma 

Thracia 

Of these, Yoldia and Thracia occur intertidally as well 

as at depths of more than 20 m. 

The turrids Taranis, Spirotropis, and Aforia have 

been found at depths no shallower than 180, 730, and 60 

m respectively. But of the 10 collections made at 

localities in which the turrids are common, 2 contain 

Neve rita (Glossaulax), which lives intertidally to 45 m, 1 

contains Spisula, which lives intertidally to 45 m; and 4 

contain Panopea, which is intertidal to possibly subtidal. These facts indicate either that the turrids lived in 

much shallower water during middle Oligocene time 

than they do now, or that their shells were mixed, before 

being fossilized, with the shells of genera with which 

they did not live. 

Thin coal seams, found in the Pittsburg Bluff Formation, indicate that the marine environment of the 

Pittsburg Bluff Formation was at times intertidal or 

supratidal. None of the mollusks found near the coal 

beds, however, are indicative of brackish water. 

If the Pittsburg Bluff fauna is regarded as primarily 

representing a single habitat, it must have lived for the 

most part in water from about 20 to about 50 m in depth. 

Mytilus and Panopea perhaps were carried in 

mechanically from shallower water, althoughMytilus is 

found at a depth of 45 m andPanopea is believed to enter 

the subtidal realm. In addition, the fossilized valves of 

Panopea in the Pittsburg Bluff fauna are usually articulated, so that if they were moved any appreciable 

distance, they must have moved rapidly. The shoreline 

must presumably have fluctuated sufficiently to include 

the coal. The turrids, unless the bathymetric data for 

the Holocene genera are nonrepresentative, are incompatible with a 20- to 50-m depth habitat. It seems 

more probable that the Pittsburg Bluff fauna includes 

species from three distinct habitats, brought together 

by transportation. Some of the mollusks must have been 

moved about for long periods of time or have been 

abraded in a high-energy environment for, as stated 

earlier, about half of the matrices of the mollusks consist of worn shell fragments of the same species as those 

that are found whole. The complete shells enclosed in 

this fragmental material are well preserved, and most 

of the pelecypod valves are articulated and closed. 

In addition to the closed and articulated valves of 

strongly hinged Acila, less strongly hinged Callista, 

Spisula, Solen, Eosolen, and Panopea are usually 

preserved with both valves closed, and fine sculpture is 

preserved on most of the gastropods. These wellpreserved shells could not have been rolled by waves or 

currents for long distances; they cannot, on the other 

hand, have been fossilized where they lived, as none 

have been found in life position, and fossil remains of 

organisms that must have lived at different depths, in 

terms of modern known bathymetric ranges, are 

commonly assembled. 

The concentrated fossilized shells and shell fragments may have been brought together in stormy 

periods. At the present time, after a storm on the coast of 
PITTSBURG BLUFF FORMATION 19 

southern California, one may find on the shores of coves 

large quantities of newly assembled worn shell debris 

mixed with unworn whole shells of Cypraea, Olivella, 

Astraea, Haliotis, Fissurella, Tegula, and other gastropods, and often large numbers of pelecypods, such as 

Mytilus, that have been washed in while they were 

alive, with their valves articulated and closed. After one 

fall storm at Jones Beach on the Atlantic Ocean side of 

Long Island, New York, mature specimens of Spisula 

solidissima Dillwyn, Neverita duplicata (Say), and the 

seastar Brisaster were piled up along the shore to a 

depth of 0.3 mover a distance of about 0.8 km. All these 

animals were alive, and the valves of Spisula were 

articulated and closed; none of them are commonly 

found on the beach in calm weather (Anthony D' Attilio, 

oral commun., 1973). Similar accumulations of live but 

displaced animals may be formed even more commonly 

in the subtidal zone. 

If the intertidal genera cited lived on sand or mud 

bars in a bay, they would have been especially vulnerable to transportation and fairly rapid redeposition during storms. 

The composition of the molluscan fauna remained 

generally the same throughout the deposition of the 

Pittsburg Bluff Formation. Mixtures of shells and shell 

debris from animals that lived at different depths occur 

throughout the section. 

The Pittsburg Bluff Formation is a transgressive unit 

that prograded westward over the deeper water Keasey 

Formation. Its thickness of 100 m or more from the base 

to the first coal bed may give a rough measure of the 

greatest water depth during its deposition. The sediments in the lower part of the formation and much of 

the sediments in the upper part are believed to have 

been carried to their present position by grain flowage 

(Stauffer, 1967) on a seaward-building slope at the 

margin of a basin. Sediment continuously spilled over 

the shelf edge and was then moved periodically into 

deeper water by grain flowage. This mechanism was 

responsible for the mixing of faunas characteristic of 

different depths. It also, by juxtaposing species of different facies at a time of fairly rapid speciation and 

extinction, contributed to the sharp faunal contrast 

between the Pittsburg Bluff Formation and the underlying Keasey Formation. 

Evidence regarding the temperature at which the 

Pittsburg Bluff fauna lived is somewhat contradictory. 

Modern Truncacila prefers a cool-temperate habitat. 

Most species of Crenella live in cool water, and 

Lucinoma prefers cool water. Panopea is usually found 

in areas of temperate climate, although it ranges into 

warm temperate waters. Yoldia (Kalayoldia) cooperi, 

probably a close relative of the extinct species ofYoldia 

in the Pittsburg Bluff Formation, now lives no farther 

north than central California. The extinct Litorhadia, 

which is common in the Eocene of Alabama and is there 

associated with warm-water genera, probably preferred 

warm water, unless it had a broad tolerance. Callista is 

usually found in warm water. 

Cryptonatica is commonly a boreal form and Aforia 

prefers cool water. Neverita (Glossaulax) reclusiana, 

probably closely related to the extinct Pittsburg Bluff 

species, lives no farther north than southern California. 

The extinct genera Eosiphonalia, Bruclarkia, 

Molopophorus, Priscofusus, and Perse are all moderately well sculptured, a fact indicating that they may 

have preferred warm water, and all these extinct genera 

exceptEosiphonalia andBruclarkia occur in the Eocene 

of California, a further indication of possible preference 

for warm water. Architectonica, a tropical genus, is 

found in the upper part of the Pittsburg Bluff sections 

near coal beds, perhaps indicating shallower and, 

therefore, warmer water. 

Some species, such as Acila (Truncacila) shumardi 

andCallista (Macrocallista) pittsburgensis, ranged from 

the Alaska Peninsula to California in middle Oligocene 

time. This wide geographic range may result from any 

one of three causes: these species may have been able to 

tolerate unusually wide temperature ranges; the 

favorable temperature may have been produced by 

differences in local water depth or by upwelling; or the 

surface temperature of the sea may have been more 

uniform in Oligocene time than it is today. 

In summary, the fauna is neither tropical nor boreal 

in overall aspect; it seems to indicate a warm-temperate 

sea. 

Tropical and subtropical molluscan genera lived only 

at low latitudes during the Oligocene and at higher 

latitudes during the Miocene, after which they steadily 

retreated southward. Addicott (1969, 1970a) has inferred from these facts that there was a marked cooling in 

middle Oligocene time, but the Pittsburg Bluff fauna 

does not seem to support this view. 

RELATION TO OTHER OLIGOCENE FAUNAS IN OREGON 

Only a few species are common to both the Keasey and 

Pittsburg Bluff Formations in the Vernonia area. In the 

past this was explained by assuming that the two 

formations were separated by an unconformity or 

disconformity, marking a time interval sufficiently long 

to account for the faunal change; but if the two formations are conformable, as indicated by the present 

study, this explanation is no longer valid. The species 

common to both formations are: 

Gastropods 

Sinum aff. S. obliquum 

(Gab b) 

Scaphander stewarti 

Durham 

Pelecypods 

Crenella porterensis 

Weaver 

N emocardium 

lorenzanum (Arnold) 
20 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

A few more genera are common to the two formations 

but are represented by different species. They are: 

Gastropods 

Cryptonatica 

Polinices 

Bruclarkia 

Spirotropis 

Pelecypods 

Nucula 

Acila 

Yoldia 

Thracia 

Pitar 

Most of the moll usc an genera do not occur in both 

formations. Genera that occur only in the Keasey or 

only in the Pittsburg Bluff Formation are: 

Keasey Formation 

Gastropods 

Turcicula 

Epitonium (2 species) 

Echinophoria 

Gyrineum 

Olequahia 

Mitra 

Cancellaria (3 species) 

Conus (2 species) 

Ex ilia 

~~Gemmula" 

Nekewis (2 species) 

Pelecypods 

Solemya 

Malletia? 

Tindaria? 

Porterius 

Delectopecten 

Lima 

Cardiomya 

Thyasira 

Macoma 

Pittsburg Bluff Formation 

Gastropods 

Architectonica 

Opalia 

Crepidula 

Neve rita 

Eosiphonalia 

Molopophorus 

Prisco{ us us 

Perse 

Aforia 

Taranis 

S uavodrillia 

Odostomia 

Acteon 

Pelecypods 

Litorhadia 

Mytilus 

Cyclocardia 

Lucinoma 

Felaniella 

Callista 

Spisula 

Ervilia? 

Tellina 

Solen 

So lena 

Panopea 

Cochlodesma 

Although none of the Pittsburg Bluff genera in these 

lists, except for the turrids, now usually live in moderately deep water at depths below 50 m, several Keasey 

genera do; among these are Turcicula, Phanerolepida, 

Solemya, Delectopecten, and Thyasira. The entire 

Keasey fauna suggests depths greater than 50 m, as the 

average modern bathymetric range of the Holocene 

genera represented is about 40-130 m. 

The fauna of the middle Keasey, which is especially 

well preserved, includes many forms that have seldom. 

been found fossilized in other Tertiary sections (Zullo 

and others, 1964, p. 333). The echinoid Salenia is 

represented at one locality by several hundred 

specimens, many of which have their spines still intact. 

At the same locality, the crinoidlsocrinus is found with 

the arms attached to the calyx. The following taxa are 

reported from the upper middle Keasey Formation at 

Mist, Oreg. (Zullo and others, 1964, p. 334-335): 

Taxa Abundance 

Foraminifera 

Operculina sp __________________ Rare 

Plectofrondicularia packardi 

Cushman and Schenck ________ Abundant 

Coelenterata 

Caryophyllia sp. indet __________ One specimen 

Flabellum hertleini Durham ____ Thirty-two specimens 

in a block with 

a surface area 

of 520 cm2. 

Gorgonid coraL_________________ One specimen 

Pelecypoda 

Acila (Truncacila) 

nehalemensis Hanna __________ Several 

Delectopecten sp ________________ Several 

Ennucula sp. 

Minormalletia sp. 

N uculana aff. N. washingtonensis 

(Weaver) 

Propeamussium n. sp. 

Solemya (Acharax) 

willapaensis Weaver __________ Few 

Tellina sp. 

Yoldia (Portlandella) 

chehalisensis (Arnold) 

Gastropoda 

"Cancellaria" sp. 

Epitonium keaseyensis Durham__ One specimen 

Exilia lincolnensis Weaver 

Fulgurofusus n. sp. 

Polinices n. sp. 

Scaphander stewarti Durham 

Arthropoda 

Fragmentary crustacean remains__ Few 

Crinoidea 

Isocrinus nehalemensis 

Moore and Vokes ____________ Several 

Isocrinus oregonensis 

Moore and Vokes ____________ Common 

Asteroidea 

Brisingid? n. sp ________________ One specimen 

Astropecten? n. sp -------------·- Three specimens 

Unidentified asteroids __________ Two specimens 

Ophiuroidea 

Unidentified ophiuran 

Echinoidea 

One specimen 

Brisaster maximus Clark? ______ One specimen 

Salenia schencki Kaar __________ Several hundred 

Vertebrata 

Fish scales ____________________ Common 

Plantae 

Coralline algae ________________ One fragment 

"Zostera" sp. (with attached 

diatoms)______________________ Few 
PITTSBURG BLUFF FORMATION 21 

Taxa-Continued Abundance-Continued 

Plantae-Continued 

Quercus consimilis Newberry 

Myrica sp. 

Thuja sp ---------------------- Few 

Ocotea eocernua Chaney and 

Sanborn______________________ One specimen 

. This biota represents a mixed depth assemblage. It 

Includes, for example, the eelgrass Zostera, which lives 

at depths of less than 15m, and the coral Flabellum and 

the echinoid Salenia, which both suggest a depth of 

about 360m (Zullo and others, 1964, p. 335). The intact 

skeletons of the echinoids, seastars, and crinoids further 

suggest that these animals lived at a depth of more than 

150 m, undisturbed by waves and currents. The gastropod Phanerolepida has been found in the middle 

member of the Keasey Formation; it lives today at 

depths of600-800 m (Hickman, 1972). Moore and Vokes 

(1953, p. 140) inferred, from the abundance of tuff in the 

middle and upper members of the Keasey Formation 

which also contains lapilli at least 1 em in diameter: 

that the source ofthe volcanic debris was nearby. Since 

no evidence of submarine volcanic activity was seen to 

acc?unt for the ash, Moore and Vokes (1953, p. 118) 

beheved that the Keasey shoreline was only a few miles 

away. 

About 4 km north of Mist, Oreg., fossiliferous conglomerate and massive sandstone are exposed. Warren 

Grivetti, and Norbisrath (1945) assigned them to th~ Gri_es Ranch Formation of early Oligocene age. They 

beheved that this part of the Gries Ranch Formation 

might ~e equivalent to the upper part of the Keasey 

Form~twn at_ Vernonia and that part of the Keasey 

contains species found in the type Gries Ranch fauna. 

Warren and Norbisrath (1946, p. 228) believed that the 

faunal differences between the two might be ascribed to 

different ecologic conditions. The Gries Ranch at this 

Oregon locality contains the following genera that do 

not occur in either the Keasey or Pittsburg Bluff 

Formations: 

Gastropods 

Puncturella 

Alvania 

Pelecypods 

Glycymeris 

Area 

Barbatia 

Loxocardium 

As species of all these genera now live in intertidal 

environments, some of them on or under loose fragments of rock, it seems likely that at least the upper part 

of the Gries Ranch Formation was deposited within a 

few kilometres of the shoreline. Absence of the genera in 

the Keasey may be due to an uncongenial depth of 

water. 

The upper part of the Keasey Formation contains the 

deepwater genus Turcicula. The upper part does not 

contain the generally deep-water genera Solemya, 

Propeamussium, Delectopecten, Thyasira, and Spirotropis. This fact may indicate a slight shoaling of the sea 

in late Keasey time. 

One fossil collection (USGS M387 4) from a siltstone of 

Keasey-like lithology taken near the base of the 

Pittsburg Bluff Formation contains Nemocardium 

lorenzanum. This species also occurs in the upper 

Keasey. In the type locality of the Pittsburg Bluff 

Formation, however, sandstone only a few metres above 

the base yields a typical Pittsburg Bluff fauna. The 

distribution ofN.lorenzanum at this place is believed to 

have been ecologically controlled; it could live in the 

facies represented by the siltstone but not in the 

sandstone facies. 

Acila (Truncacila) nehalemensis was collected in the 

Keasey Formation about 2 m below its top (USGS 

M3864). Acila (Truncacila) shumardi is common 

throughout the lower part of the Pittsburg Bluff 

Formation in the type area. These two very distinct 

species ofAcila occur only a few metres apart, the one in 

the Keasey and the other in the Pittsburg Bluff. They 

are, however, in different kinds of rock, A. (T.) 

nehalemensis in shale and A. (T .) shumardi in 

sandstone. In the Gries Ranch Formation in northwestern Oregon, the Pittsburg Bluff spec~es A. (T.) 

shumardi is found rather than the Keasey species A. 

(T.) nehalemensis, but as the Gries Ranch Formation 

was deposited in much shallower water than the 

Keasey, this difference can be attributed to a difference 

of environment. 

In the Eugene area, about 200 km south of Pittsburg, 

Oreg., the Eugene Formation, of early and middle 

Oligocene age, contains both Keasey and Pittsburg 

Bluff species. Although some typical Pittsburg Bluff 

species, such as Callista pittsburgensis, Acila shumardi, 

andBruclarkia columbiana, do not appear until high in 

the section, other Pittsburg Bluff species, such as Tellina pittsburgensis, Solena eugenensis, Thracia condoni, Litorhadia washingtonensis, Tellina aduncanasa, 

Polinices washingtonensis, andNeverita thomsonae, are 

present lower in the section, and are all associated with 

typical Keasey forms (Hickman, 1969, p. 11). The 

Eugene Formation, which interfingers with terrestrial 

deposits, consists entirely of coarse- to fine-grained 

sandstone, whereas sediments of presumably the same 

stratigraphic interval are represented in northwestern 

Oregon by fine-grained sandstone and siltstone of the 

Pittsburg Bluff Formation and shale of the Keasey 

Formation. These differences of lithology indicate that 

the two areas offered somewhat different ecologic 

habitats. 
22 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

High in the Eugene Formation, where typical 

Pittsburg Bluff species are common, the following genera were found that do not occur in the Pittsburg Bluff 

Formation: 

Gastropods 

Epitonium 

Acrilla 

Calyptraea 

Ficus 

Olequahia 

Exilia 

Gem mula 

Cylichnina 

Pelecypods 

Modiolus 

Parvicardium 

Pseudocardium 

Macoma 

Semele 

My a 

Pandora 

Opertochasma 

Martesia 

Most of these mollusks from the Eugene Formation 

could have lived within the environmental range of the 

Pittsburg Bluff Formation, both as to depth and seasurface temperature. The following genera occur in the 

Keasey but not in the Eugene Formation: 

Gastropods 

Turritella 

Echinophoria 

Gyrineum 

Mitra 

Cancellaria 

Spirotropis 

Nekewis 

Knefastia 

Pelecypods 

Solemya 

Ennucula 

Minormalletia 

Tindaria? 

Porterius 

Delectopecten 

Lima 

Cardiomya 

Thyasira 

As the mean depth at which many of these genera now 

live (40--100 m or more) is greater than the mean indicated by the inner neritic Eugene fauna as a whole, 

some of the Keasey Formation may have been deposited 

in deeper water than any part of the Eugene Formation. 

Crinoids are not found in the Eugene Formation, 

reinforcing the conclusion that the habitat was different 

from that of the Keasey and that it differed in some 

respect other than sea-surface temperature, since the 

two geographic areas are only about 200 km apart. 

The known distribution of genera in the lower, middle, and upper Keasey is shown in table 3 along with 

genera that also occur in the Eugene and Pittsburg 

Bluff Formations. 

In the Coos Bay area, about 260 km southwest of 

Pittsburg, Oreg., the middle Oligocene Tunnel Point 

Sandstone rests conformably upon the Bastendorff 

Shale (late Eocene and early Oligocene). The molluscan 

fauna of the Tunnel Point is reported to contain typical 

Pittsburg Bluff species and no Keasey species. Genera 

found by Weaver (1945, p. 51) in the Tunnel Point but 

not in the Pittsburg Bluff are: 

Gastropods 

Exilia 

Neptunea 

Pelecypods 

Corbis 

Macoma 

Pachydesma 

Pecten 

Pholas 

Thyasira 

The underlying Bastendorff Shale contains nQ Tunnel 

Point species. Its meager molluscan fauna includes 

Acila aff.A. decisa (Conrad),Nuculana cf.N. merriama 

(Dickerson), Spisula cf. S. packardi Dickerson, 

Cylichnina turneri Effinger, and Dentalium cf. D. 

porterensis Weaver. Of the 16 foraminifers reported by 

Weaver (1945, p. 49) in the Bastendorff, 7 occur in the 

Keasey. The foraminifers in the upper 300 m of the 

Bastendorff Shale indicate moderately deep to abyssal 

water depths (Kleinpell, 1938, p. 102). So even though 

Coos Bay is much farther south and nearer to the present coast, the depositional-faunal sequence is analogous to that of the Keasey and Pittsburg Bluff Formations in northwestern Oregon. 

TABLE 3.-Distribution of molluscan genera in the lower, middle, and 

upper parts of the Keasey Formation and their occurrence in the 

Pittsburg Bluff and Eugene Formations 

[Compiled from Moore and Vokes, 1953, and Hickman, 1969] 

Keasey Formation 

Genera Euge~e PiMl~ffg Lower Middle Upper FormatiOn Formation 

part part part 

Pelecypods: 

Solemya ________________ x Ennucula _______________ _ 

Acila (Truncacila)________ x lVuculana _____________ _ Yoldia _________________ _ 

Minormalletia _________ _ Porterius _______________ _ Propeamussium _________ _ Delectopecten ___________ _ Lima ___________________ _ 

Crenella _______________ _ Thracia _______________ _ Thyasira ________________ x 

lVemocardium _________ _ Fimbria ________________ x Pitar ____________________ x Tellina __________________ _ 

Gastropods: 

Turcicula________________ X 

Epitonium -------------- Polinices _______________ _ Turritella r ______________ _ 

Echinophoria ___________ _ Gyrineum _____________ _ Olequahia _____________ _ Bruclarkia _____________ _ Cancellaria _____________ _ Conus __________________ X 

Exilia _________________ _ 

f:ulgurofu~z:s ------------ Gemmula _____________ _ lVekewis _______________ _ Scaphander _____________ _ 

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 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 
PITTSBURG BLUFF FORMATION 23 

In northwestern Oregon the Keasey Formation, 

represented by shale, and the Pittsburg Bluff Formation, represented by sandstone, are comformable but 

have almost no species in common; in southwestern 

Oregon, the Bastendorff Shale and the Tunnel Point 

Sandstone are conformable and contain no species in 

common. In both areas, depth of water is believed to be 

the controlling factor explaining the abrupt faunal 

break between early and middle Oligocene formations. 

In the Newport area, on the coast of Oregon north of 

Coos Bay, the Alsea Formation, considered early, 

middle, and late Oligocene by Snavely, MacLeod, Rau, 

Addicott, Pearl, and Quinterno (1975), is conformably 

overlain by the Yaquina Formation (late Oligocene and 

early Miocene) and unconformably underlain by the 

Nestucca Formation (late Eocene). The Alsea Formation has yielded 35 species of mollusks (Vokes and 

others, 1949); and 13 of these also occur in the Pittsburg 

Bluff Formation. The upper part of the Alsea Formation 

contains mollusks of provincial late Oligocene age 

(Warren 0. Addicott, written commun., 1973). 

The following genera are represented in the Alsea 

Formation but not in the Pittsburg Bluff Formation: 

Gastropods Pelecypods 

Calyptraea Lucina (Here) 

Liracassis Loxocardium? 

Exilia Macoma 

Ancilla Apolymetis 

There are no obvious differences in ecologic requirements between these genera and those in the 

Pittsburg Bluff Formation. 

Two small, poorly preserved molluscan faunas were 

collected in the Newport area, one of which has been 

correlated with a fauna from the Gries Ranch Formation, the other with a fauna from the Keasey Formation (Vokes and others, 1949). Further investigation 

may show that there was a close ecologic relation 

between the Newport area and the Pittsburg area during early and middle Oligocene time. 

SUMMARY 

Many of the genera found in the Keasey Formation 

are not found in the Pittsburg Fluff Formation. This 

curious fact can perhaps be explained as a result of 

differing habitats; the extinction of genera is not involved as most of these genera are still living today. The 

Keasey fauna lived predominantly in moderately deep 

water, at depths greater than 50 m, on a bottom of silt, 

whereas the Pittsburg Bluff fauna lived predominantly 

in water shallower than 50 m, on a bottom of fine sand. A 

similar ecologic difference existed near Coos Bay during 

the deposition of the Bastendorff and Tunnel Point 

Formations, equivalent to the Keasey and the Pittsburg 

Bluff Formations, respectively. The Gries Ranch 

Formation, a shallow-water equivalent of the upper 

part of the Keasey Formation, contains 10 Pittsburg 

Bluff species, a strong indication that ecology is the 

limiting factor. 

The Eugene Formation may have been deposited in 

an environment in which the elements of the Keasey 

fauna that could tolerate shallower water, of 50 m or 

less, could live. 

AGE 

The first Pacific coast fossils to be assigned to the 

Oligocene were the mollusks collected by Diller near 

Pittsburg, Oreg., and later identified by Dall (Diller, 

1896, p. 466). Presumably Dall's assignment was based 

on a comparison of the genera with those of the 

Oligocene of Europe and on the percentage of living 

taxa. Dall's first assignment of the Pittsburg Bluff 

fauna to the Oligocene has been endorsed by most other 

molluscan specialists, on the basis of comparison at the 

generic level of its mollusks with those from the 

Oligocene of the Gulf Coast and of Europe, of superposition, and of the marked change in the molluscan 

fauna at the end of the Eocene, when many genera 

disappeared and others made their first appearance. 

In 1936 Schenck and Kleinpell proposed the Refugian 

Stage for part of the Pacific coast Tertiary. They designated as the type locality for this stage Canada de 

Santa Anita, on the south side of the Santa Ynez 

Mountains, Santa Barbara County, Calif., about 5 miles 

west of Gaviota Pass. Schenck and Kleinpell (1936, p. 

219) stated that ~~***the Refugian stage comprises the 

rocks deposited after the strata usually included within 

the Tejon Formation (restricted) were laid down and 

before the Zemorrian Stage." They believed that the 

Refugian Stage is ~~probably equivalent in age to a 

portion of the upper Eocene or lower Oligocene series of 

Europe." They considered it to be represented in Oregon 

by the Eugene, Pittsburg Bluff, Tunnel Point, Keasey, 

and Bastendorff Formations, in Washington, by the 

Lincoln [Lincoln Creek] and Gries Ranch Formations. 

They also believed that the Refugian Stage included the 

Acila shumardi Zone and was roughly equivalent, in its 

type area, to the Turritella variata Zone. 

According to Schenck and Kleinpell, the Keasey 

species Acila (Truncacila) nehalemensis Hanna first 

appears in the basal part of the Refugian Stage (1936, p. 

220--221). The Pittsburg Bluff species Acila (Truncacila) shumardi (Dall), Callista pittsburgensis Dall, 

Molopophorus gabbi Dall, and Bruclarkia columbiana 

(Anderson and Martin) make their last appearance in 

the uppermost part of the Refugian Stage (Schenck and 

Kleinpell, 1936, p. 221). 

Addicott (1972), in a paper on the provincial mollus-
24 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

can stages of the Temblor Range in California, discusses 

the Refugian Stage (p. 5), calls it early Oligocene (p. 4, 

fig. 3), and states that the Refugian and Zemorrian 

Stages in this area are at least in part coeval. He bases 

this conclusion on the occurrence of the Refugian index 

species Bruclarkia columbiana in strata that can readily be traced to the lowermost part of the type Zemorrian 

Stage of Kleinpell (1938). 

In 1963 Weaver and Kleinpell published an exhaustive study of foraminiferal and molluscan faunas from 

the Gaviota and Alegria Formations in the Santa 

Barbara embayment of California, which contains the 

type area of the Refugian Stage. One of the most 

noteworthy provincial correlations made by Weaver 

and Kleinpell on the basis of foraminifers and mollusks 

was that of the Bastendorff and Keasey Formations 

with the middle and upper members of the Gaviota 

Formation and an implied correlation of the lower 200 

feet of the Alegria Formation (the uppermost part of the 

~~Turritella variata Zone") with the Lincoln Creek 

Formation of Washington and its equivalents, which 

would include the Pittsburg Bluff Formation (Weaver 

and Kleinpell, 1963, p. 45). 

Weaver and Kleinpell believe that several West 

Coast formations usually considered to be of early or 

middle Oligocene age, are on the basis of mollusks, in 

whole or in part of the same age as the Turritella variata 

Lorenzana Zone of Santa Barbara. These formations are 

the middle and upper parts of the Bastendorff, the 

Tunnel Point, the Keasey, the Pittsburg Bluff, the Gries 

Ranch, and the Lincoln Creek Formations (Weaver and 

Kleinpell, 1963, p. 113-114). Although they found few 

molluscan species that are common to the Pacific 

Northwest and the Santa Ynez Mountains of California, 

they felt that these few are exceptional in their apparent stratigraphic fidelity. The occurrence of Acila 

nehalemensis in the upper Gaviota beds of the Santa 

Ynez Range makes it possible to correlate these beds 

with the middle and upper Bastendorff and the Keasey 

Shale. The Lincoln Creek Formation can be correlated 

with the lower part of the Alegria Formation-the 

Turritella variata-bearing members A to C. They 

conclude that the Turritella variata Zone, since it 

contains 1-2 percent of living species and some giant 

venericards, is late Eocene and perhaps early 

Oligocene, and that the Refugian Stage is therefore late 

Eocene and perhaps very early Oligocene (Weaver and 

Kleinpell, 1963, p. 118). 

Schenck and Kleinpell (1936) defined the Refugian 

Stage on the basis of its carefully delineated type section, and although they used local first and last appearances of both benthonic foraminifers and mollusks 

to mark the boundaries, they then did not intend stratigraphic range extensions to change the definition of the 

stage (p. 221). Although other stages have been defined 

on the basis of provincial fossil zones, the Refugian was 

originally intended to be of fixed geologic age-the age 

of its type section. In recent years the Refugian has 

taken on more the character of a stage based exclusively 

on foraminiferal zones. This reduces its usefulness in 

molluscan paleontology because the provincialism of 

both benthonic foraminifers and mollusks is measurably significant over the distance from the type locality of 

the Refugian to, for example, the type locality of the 

Pittsburg Bluff Formation. Whereas in original concept 

the Refugian Stage might have had lasting utility in 

broad-scale West Coast stratigraphy, at this time it 

seems difficult, if not impossible, to use it judiciously. 

The type locality for Acila (Truncacila) shu mardi of 

theAcila shumardi Zone of Schenck (1936) is at the type 

locality ofthe Pittsburg Bluff Formation, and theAcila 

shumardi Zone has been recognized since 1936 in all the 

Pacific coast states, including Alaska, and has always 

been assigned to the Oligocene. 

Durham (1944) proposed magafaunal zones for the 

Tertiary of southwestern Washington; one ofthese was 

theM olopophorus gabbi Zone. M. gabbi is a common and 

characteristic species of the Pittsburg Bluff Formation. 

Presumably because M. gabbi is not as widespread 

geographically in its occurrence as Acila shumardi, the 

Molopophorus gabbi Zone is not as widely used as the 

Acila shumardi Zone. The Molopophorus gabbi Zone is, 

however, roughly equivalent to at least the lower part of 

the Acila shumardi Zone. 

Durham listed as characteristic of the Molopophorus 

gabbi Zone the species Bruclarkia columbiana, 

Molopophorus dalli, Perse olympicensis quimpersensis, 

P. pittsburgensis, and Spisula pittsburgensis; all but 

Perse olympicensis and Molopophorus dalli occur in the 

Pittsburg Bluff Formation. Molopophorus dalli, which 

Durham includes in the Molopophorus gabbi Zone, does 

not occur at the same horizon as M. gabbi in northwestern Oregon; it seems to be an older species, restricted to 

the early 0 ligocene. 

The position of the provincial Oligocene-Miocene 

boundary has been in dispute for many years (Moore, 

1963, p. 1-2), and complete agreement still has not been 

reached. The problems concerning the EoceneOligocene boundary seemed to be nearing solution, with 

generally good agreement, until fairly recent years. In 

the most extreme example of these recent problems, 

Eames, Banner, Blow, Clarke, and Cox (1962) published 

a paper on mid-Tertiary correlation in which they denied that there is Oligocene at all on the western coast of 

North America. 

David Bukry (written commun., 1973) considers a 

sample from USGS locality M3865, about 100m below 

the top of the Keasey Formation, to be late Eocene or 
PITTSBURG BLUFF FORMATION 25 

earliest Oligocene in age on the basis of the following 

coccoliths that he was able to identify. 

USGS locality M3865. Railroad cut adjacent to 

State Highway 4 7, 0.5 km south of main street of 

Vernonia, Oreg., at 45°51.3' N., 123°11.8' W. 

Braarudosphaera bigelowii (Gran and Braarud) 

Chiasmolithus oamaruensis (Deflandre) 

Coccolithus eopelagicus (Bramlette and Riedel) 

Coccolithus pelagicus (Wallich) 

Cyclicargolithus sp., cf. C. floridanus (Roth and 

Hay) 

Dictyococcites bisectus (Hay, Mohler, and Wade) 

Dictyococcites scrippsae Bukry and Percival 

Isthmolithus recurvus Deflandre 

Many authors have cited the difficulties of provincial 

correlation in the Oligocene. Whereas the Eocene 

permits fairly easy correlations over wide areas, and the 

Miocene permits reasonable correlations, the Oligocene 

has always been troublesome in this respect. The usual 

explanations for the difficulty with the Oligocene have 

been (1) that the basins of deposition were isolated and 

(2) that distinctive Caribbean elements in the Eocene 

faunas migrated southward in Oligocene time. The 

problem of precise correlation is further complicated by 

the fact that since the most useful planktonic species of 

foraminifers and coccoliths do not commonly occur with 

the nearshore molluscan faunas either on the Pacific 

coast or at the European stratotype localities, detailed 

studies of interfingering of facies are required in both 

regions. And, the original series and stages in Europe 

were not as carefully defined as might have been desired 

(Fischer and others, 1971). However, the age determination by David Bukry given above, based on coccoliths from the middle Keasey as defined by Moore and 

Vokes (1953, p. 115, fig. 28), provides new evidence from 

this cosmopolitan planktonic fossil group for a late 

Eocene and early Oligocene age for the Keasey Formation and its correlatives. On the basis of superposition and its contained fauna, the overlying Pittsburg 

Bluff Formation is assigned to the middle Oligocene. 

The sum of all paleontologic and stratigraphic evidence 

now available indicates that the Pittsburg Bluff 

Formation is of provincial middle Oligocene age. 

CORRELATION 

The marine lower and middle Oligocene sedimentary 

rocks of the Pacific Northwest range in facies from 

conglomerate (Gries Ranch Formation) through 

sandstone (Eugene Formation) and fine-grained 

sandstone and siltstone (Pittsburg Bluff Formation) to 

deepwater shale (Keasey Formation). In some areas, 

such as those around Newport and Eugene, Oreg., 

depositional conditions during the Oligocene were 

apparently fairly constant. In other areas, such as those 

around Pittsburg and Coos Bay, Oreg., an abrupt 

change took place at the end of the early Oligocene from 

relatively deepwater to relatively shallow-water deposition as evidenced by both the character of the 

sedimentation and the fauna. 

In the Pacific Northwest, a heavy cover of vegetation, 

discontinuous exposures, interruption by faults, and the 

recurrence of similar sediments at various horizons 

throughout the Tertiary make even local correlation 

difficult and make regional correlation impossible in 

unfossiliferous rocks. The Pittsburg Bluff molluscan 

fauna, however, although small in number of species, is 

distinctive and it includes some species of short time 

range that occur as far north as Alaska and as far south 

as southern California. It therefore permits considerable confidence in provincial correlation. 

The distribution of Pittsburg Bluff species in some 

other formations of late Eocene, Oligocene, and early 

Miocene age and Pittsburg Bluff species not known to 

occur outside the Pittsburg Bluff Formation is given in 

table 4. A total of 48 species of mollusks has been 

identified in the Pittsburg Bluff; 9 of these are not now 

known to occur elsewhere. The number of species that 

occur in other formations with which the Pittsburg 

Bluff Formation has been precisely or approximately 

correlated, listed in north to south order, is as follows: 

Number of 

Formation species 

in common 

Stepovak Formation of Burk (1965) 3 

Poul Creek Formation __________________ 9 

Quimper Sandstone of Durham (1942) ____ 9 

Gries Ranch Formation__________________ 10 

Lincoln Creek Formation ________________ 14 

Alsea Formation------------------------ 13 

Eugene Formation ______________________ 17 

Tunnel Point Sandstone ________________ 11 

San Lorenzo Formation__________________ 3 

Wygal Sandstone Member of 

Temblor Formation __________________ 3 

Cymric Shale Member of 

Temblor Formation __________________ 1 

Kirker Tuff----------------------------- 2 

Tumey Formation of Atwill (1935) ______ 3 

San Emigdio Formation ________________ 2 

Alegria Formation of Dibblee (1950) ______ 1 

Of the total number of Pittsburg Bluff species, 28 

species, or 58 percent, are known to occur in other 

formations of middle Oligocene age; 12 species, or 25 

percent, occur in early Oligocene formations; and 10 

species, or 22 percent, occur in formations assigned to 

the late Oligocene or early Miocene. Only two species 

are found in late Eocene formations. 

The correlation chart (fig. 7) indicates graphically the 
TABLE 4.-Distribution of Pittsburg Bluff species in some other formations of late Eocene, Oligocene, and early Miocene age 

Species 

Gastropods: 

Architectonica blanda Dall _________________ _ 

Turritella pittsburgensis, n. sp. _____________ _ 

Opalia Wentiscala?i hertleini, n. sp. _________ _ Crepidula pileum (Gabbl ___________________ _ 

Cryptonatica pittsburgensis, n. sp. ___________ _ Po/inices washingtonensis (Weaver) _________ _ 

Neverita (Glossaulax) thomsonae Hickman ___ _ Eosiphonalia oregonensis (Dal!) ____________ _ 

Bruclarkia columbiana (Anderson and Martini Molopophorus gabbi Dall ___________________ _ 

Priscofusus stewarti (TeglandL ______________ _ Perse pittsburgensis Durham _______________ _ 

Perse pittsburgensis vernoniensis, n. subsp. ___ _ Aforia campbelli Durham ___________________ _ 

Taranis columbiana (Anderson and Martini __ Spirotropis kincaidi (Weaver) _______________ _ 

Suavodrillia winlockensis (Effinger) _________ _ Odostomia winlockiana Effinger _____________ _ 

Acteon chehalisensis (Weaver)_ 

Scaphander stewarti Durham ______ _ 

Scaphopod: 

Dentalium (Fissidentalium?llaneensis Hickman 

Pelecypods: 

Nucula (Leionucula) vokesi, n. sp. ___________ _ 

Acila (Truncacila l shumardi (Dall) Litorhadia washingtonensis (Weaver) _______ _ 

Yoldia (Kalayoldial oregona (Shumardl _____ _ Crenella porterensis Weaver _______________ _ 

Lucinoma columbiana (Clark and Arnold) ___ _ Felaniella Welaniella) snavelyi, n. sp. _______ _ 

Nemocardium (Keenaea) lorenzanum (Arnoldi Pitar (Pitarl dalli (Weaver) _________________ _ 

Callista <Macrocallista) pittsburgensis DalL __ _ Spisula (Mactromeris) pittsburgensis Clark ___ _ 

Spisula (Mactromeris?) veneriformis Clark ___ _ ?Ervilia oregonensis Dall ___________________ _ 

Tellina (Eurytellina) aduncanasa Hickman ___ _ Tellina? pittsburgensis Clark _______________ _ Solen townsendensis Clark _________________ _ 

Solena (Eosolen) eugenensis (Clark) ---------- Panopea snohomishensis Clark _____________ _ Panopea ramonensis Clark _________________ _ 

Cochlodesma bainbridgensis Clark Thracia (Thracia) condoni Dall ---

Alaska Washington Oregon California 

Stepov~k I Poul I Gries ~S~~d~fo~e~ M~r;-~:·1 Lincoln I Blakel~y I , I I I Tunnel I I San I Cl~r!c I Sav;:J~~~e I Tumey FormatiOn Creek Ranch of Shale Creek FormatiOn Keasey Alse~ Eugene Point Scappo?se Lorenzo Memberof Memberof FormatiOn 

of Burke Formation Formation Durham of Durham Formation of Weaver FormatiOn FormatiOn FormatiOn Formation FormatiOn Formation Temblor Temblor of Atwiii 

!19651 (19421 (19441 (19121 Formation Formation 119351 

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Alaska 3 Washington I Oregon 

I 

Series I Stage 1 Molluscan 

I 

Port North- North- zones 2 Moller Yakataga Cowlitz Southand and central eastern River western I Pittsburg Eugene6 Newport 7 Coos Bay 

Unga Malaspina Olympic Olympic Basins Washingtons 

Island districts Peninsula 4 Peninsulas 

"Echino-

~ I I phoria" Yakataga ] "Vaqueri" apta Formation 

"Beds of 

I Blakeley 

Acila age" 

~ • 

Yaquina 

? gettys- Scappoose Formation 

I "Echino- burgensis Formation Plant-bearing 

II phoria" tuffs of Goshen 

I rex localitY 

"Blakeley" 1 Lower part 

of Unga F . I Poul Creek 

Turritella orma;•~n Formation c: I as use y porterensis 

Acila R 0 

·.;::; Member shale" ctJ 

Cll c: 

I Mo/opophom• 

E 

:0 0 0 j Tunnel Point 0 lJ_ "Lincoln "'0 c: I Pltt•b"'' Bluff shu mardi Sandstone ~ :J ~ Formation" Formation Cll Alsea gabbi > 

a: Formation 

c: I c: Quimper -~ Sandstone 1-

Molopophorus Stepovak I Gries Ranch dalli·and 

Molopophorus Series of Formation 

Palache ~ > stephensoni (1904) Cll Acila 

~ Keasey Keasey ~ 5l I I Bastendorff t1l nehalem- Formation Formation 0 (I) Shale _J ~ ensis 

"Turcicula" Kulthieth Lower 

columbiana Formation Member "-.._ t'/////////////////////...1 r Fisher 

Formation 

--1 Nestucca 

Turri tel/a Not Not Crescent Cowlitz Cowlitz Cowlitz Spencer Formation Coaledo "Tejon" olequahensis named identified Formation Formation Formation Formation Formation Formation 

1 Weaver and others, 19 4 4; Addicott, 19 6 7 3 MacNeil and others, 19 61 5 Weaver and others, 19 4 ~ 7 Snavely and others, 19 6 9 , 1 9 7 6 . 2 Schenck, 1 9 3 6 ; Durham, 1 9 4 4 ; Weaver and others, 19 4 4 4 Brown and Gower, 19 58 6 Vokes and others, 19 51 ; Hickman, 19 6 9 

FIGURE 7.-Correlation chart of selected middle Tertiary stratigraphic units in Alaska, Washington, and Oregon. 

t-..:;, 

.....:) 
28 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

formations believed to be correlative entirely or in part 

with the Pittsburg Bluff Formation. Pittsburg Bluff 

molluscan species are most abundant in the Tunnel 

Point Sandstone at Coos Bay, the upper part of the 

Eugene Formation in the Willamette Valley, and the 

Alsea Formation near Newport, Oreg. Other probable 

time-stratigraphic equivalents of the Pittsburg Bluff 

Formation on the basis of mutual occurrence of species 

are: parts of the Stepovak Formation of Burke (1965) 

and Paul Creek Formation in Alaska, the Lincoln Creek 

Formation and Quimper Sandstone of Durham (1942) of 

Washington, and the Wheatland Formation of Clark 

and Anderson (1938), Tumey Formation of Atwill 

(1935), San Emigdio Formation, Wygal Sandstone and 

Cymric Shale Members of the Temblor Formation, 

Alegria Formation of Dibblee (1950), and Kirker and 

San Lorenzo Formations of California. 

A mixture of Keasey and Pittsburg Bluff species occurs throughout the Eugene Formation, as pointed out 

in the section on ecology; some typical Pittsburg Bluff 

species such as Callista pittsburgensis, Acila shumardi, 

and Bruclarkia columbianum occur only in its upper 

part. Table 5 gives all the Oligocene species that were 

found high in the Eugene Formation by Hickman (1969, 

p. 16--19). 

TABLE 5.-Checklist of Oligocene mollusks in the upper part of the 

Eugene Formation in Oregon 

[Locality numbers and occurrence are from Hickman 119691) 

Eugene area Salem area 

Locality No. 

12 28 34 35 39 41 42 44 46 47 

Pelecypods 

Acila (Truncacila) nehalemensis (G. 

D. Hanna) _____________________ _ 

Acila (Truncacila) nehalemensis 

minima Hickman ______________ x x 

Acila (Truncacila) shumardi (Dall) --

Nuculana washingtonensis 

X X X X X 

(Weaver) ______________________ x x X X 

Yoldia (Kalayoldia) oregona 

(Shumard) ______________________ x X X 

Modiolus eugenensis Clark ________ x x 

Mytilus snohomishensis Weaver X 

Parvicardium eugenense (Clark) __ x x x x x X 

Lucinoma acutilineata (Conrad) ___ _ X 

Diplodonta parilis (Conrad) ______ x x x X X 

Callista pittsburgensis (Dall) ______ x x x X 

Callista n. sp. ____________________ x x x 

Pitar (Pitar) dalli (Weaver) ______ x x x x x X 

Pitar (Pitar) n. sp.? ______________ x x 

Pitar (Lamelliconcha) clarki 

(Dickerson) ____________________ x x 

Spisula pittsburgensis Clark _______ _ X X 

Spisula eugenensis (Clark)_ _______ x x x x 

Pseudocardium sp. ________________ x x 

Tellina pittsburgensis Clark ______ x x X 

Tellina aduncanasa Hickman ______ x X X 

X 

X 

X X 

X 

X 

X 

X 

X 

TABLE 5.-Checklist of Oligocene mollusks in the upper part of the 

Eugene Formation in Oregon-Continued 

Eugene area Salem area 

Locality No. 

12 28 34 35 39 41 42 44 46 47 

Pelecypods-Continued 

Tellina? n. sp. __________________ x x 

Tellina eugenia DalL_____________ x 

Tellina (Moerella) lincolnensis 

(Weaver) ______________________ x x x 

Macoma aff. M. inquinata (Deshayes) ________________________ x x 

Macoma (Heteromacoma) vancouverensis (Clark and Anderson) x x 

Semele willamettensis Hickman ____ X 

--1--

Solena (Eosolen) eugenensis (Clark) X X X X 

Solen sicarius Gould ____________ X x x 

Mya (Arenomya?) kusiroensis 

(Nagao and Inoue) ______________ x 

Panopea (Panopea) ramonensis 

Clark __________________________ x 

Opertochasma turnerae (Hickman) X 

Martesia sp. ___________________ _ X 

Pandora (Pandora) laevis Hickman x 

Thracia condoni Dall ____________ x x X 

Scaphopod 

Dentalium (Fissidentalium ?) 

X 

X X 

X 

X 

X X 

X 

laneensis Hickman ____________ x x _______________ _ 

Gastropods 

Epitonium (Boreoscala) condoni 

(Dall) ------------------------ X X X X __ 

E. (B.) condoni oregonensis Durham 

E. (B.) condoni eugenense Durham 

Acrilla (Ferminoscala) dickersoni 

Durham _____________________ _ 

A. (F.) becki Durham ___________ _ 

Calyptraea diegoana (Conrad) ___ _ 

Calyptraea sookensis Clark and 

Arnold _______________________ _ 

X --

X X X 1 __ 

X X 

? X 

X X 

I 

Crepidula ungana Dall __________ x x 

Natica (Natica) n. sp.? ____________ x X x 

X 

X 

Neverita thomsonae Hickman ____ x X x X X 

Polinices wa~hingtonensis (Weaver) X X 

Sinum obliq;.wm (Gabb) __________ X X 

Ficus modesta..(Conrad) __________ x x 

Olequahia schencki Durham______ x x x 

Molopophorus dalli Anderson and 

Martin________________________ x 

Molopophorus fishii (Gabb) ______ x x x 

Bruclarkia vokesi Hickman ______ x x x x x 

Bruclarkia columbiana (Anderson 

and Martin) __________________ x x X X 

Perse lincolnensis (Van Winkle) __ x 

Exilia lincolnensis (Weaver) ______ x x 

Gemmula bentsonae Durham______ x x 

Acteon parvuum Dickerson ______ x 

Cylichnina turneri Effinger ______ x 

Scaphander stewarti Durham ____ x X X X 

The presence of such typical Keasey species as Acila 

(Truncacila) nehalemensis and Olequahia schencki high 

in the Eugene Formation, combined with the absence of 
SYSTEMATIC DESCRIPTIONS 29 

any typical Keasey species in the Pittsburg Bluff 

Formation, might permit considering the hypothesis 

that all of the Eugene Formation is slightly older than 

the Pittsburg Bluff Formation. Since the uppermost 

part of the Eugene Formation and the lower part of the 

Pittsburg Bluff Formation contain 19 species in 

common, they are regarded as partly coeval. 

SYSTEMATIC DESCRIPTIONS 

Phylum MOLLUSCA 

Class GASTROPODA 

Family TROCmDAE 

Unidentified trochid? 

Plate 1, figures 6, 7 

This single specimen resembles the trochid 

Bathybembix in overall outline (USNM 213948). Some 

characteristics of the specimen recall ((Turcicula" 

columbiana Dall (1909, p. 100, pl. 3, figs. 2, 11) that 

occurs in the Keasey Formation (late Eocene and early 

Oligocene) in Oregon and has been assigned to 

Bathybembix by Rehder (1955, p. 255). This specirnen 

does not have so high a spire asBathybembix, is a much 

smaller form, and measures 24 mm in maximum 

diameter. Patches of the inner shell layers are preserved, as are fairly large nodes on the periphery of the 

last whorl. The aperture and umbilicus are not preserved. 

Locality.-USGS 15312. 

Family ARCHITECTONICIDAE 

Genus Architectonica Reding 

Architectonica Roding, 1798, Museum boltenianum, pt. 2, p. 78. 

Type species.-By subsequent designation (Gray, 

1847, Zool. Soc. London Proc., pt. 15, p. 151) Trochus 

perspectivus Linne. Holocene, tropical western Pacific 

Ocean. 

Architectonica blanda Dall 

Plate 1, figures 1-4 

Architectonica blanda Dall, 1909, U.S. Geol. Survey Prof. Paper 59, p. 

80-81, pl. 3, figs. 4, 5. Weaver, 1942, Washington Univ. (Seattle) 

Pubs. Geology, v. 5, p. 364, pl. 73, fig. 7. 

Two incomplete specimens of Architectonica blanda 

are in the collections. They are distinguished by the 

smoothness of the spire and by the paired spirals on the 

periphery of the body whorl. These paired spirals are of 

equal weight on one specimen and of unequal weight on 

the other; the more posterior spiral is narrower. According to Dall (1909, p. 80), A. blanda has one strong 

spiral and one much weaker one. Four somewhat 

unequally spaced spiral grooves are visible on the base 

of the shell. Because the umbilicus and umbilical rnargin are worn and corroded on the specimens at hand and 

are covered by matrix on the type specimen of the 

species, an assignment refined to subgenus has not been 

made. 

Holotype .-USNM 107 414. Figured specimens: 

USNM 213945, 213946. 

Type locality.-USGS 2697, north fork of Scappoose 

Creek, at the mouth of Fall Creek, Columbia County, 

Oreg. Scappoose Formation (late Oligocene and early 

Miocene). 

A. blanda is the only post-Eocene species of Architectonica reported from Oregon and Washington. 

Although the type locality has been cited as middle 

Oligocene (Weaver, 1942, p. 364), it is actually in the 

Scappoose Formation of late Oligocene and early 

Miocene age. 

Localities.-USGS 15588, M3858. 

Occurrence elsewhere .-Scappoose Formation (late 

Oligocene and early Miocene), Oregon. 

Family TURRITELLIDAE 

Genus Turritella Lamarck 

Turritella Lamarck, 1799, Soc. Hist. Nat. Paris Mem., ser. 1, p. 74. 

Type species.-By monotypy Turbo terebra Linne. 

Holocene, tropical western Pacific Ocean. 

Turritella pittsburgensis, n. sp. 

Plate 3, figures 11-16; figure 8 

Turritella pittsburgensis is a small species (largest 

specimen, incomplete, 32 mm high and 10 mm wide) 

with a shell of moderate thickness consisting of probably 12 whorls. On the whorls of the spire, the two anterior spiral ribs are the most prominent, and the anterior space between them and the suture is deeply 

concave. These paired ribs are equal in weight on the 

spire, but the anterior rib becomes more prominent on 

the larger whorls nearest the body whorl. Above the 

paired spirals are two spirals of equal weight, and above 

them are two of lesser width just below the suture. 

These two finest spirals are absent on the early whorls of 

the spire. On the very earliest whorls, only the paired 

primary spirals and one secondary spiral are present; 

these spirals strongly suggest relationship to the 

bicostate Turritella uvasana stock of Merriam (1941, p. 

42- 44). On one specimen (pl. 3, fig. 14), a fine spiral is 

present between the paired anterior spirals on the 

largest preserved whorl. The body whorl is not preserved on the available specimens. The growth-line 

sinus is shown in figure 8; this deep antispiral sinus has 

the maximum swelling just above the whorl middle and 

no apparent growth-line angle. In this regard it resembles Turritella porterensis Weaver from the Lincoln 

Creek Formation (Eocene to Miocene) of Washington 

and Turritella oregonensis Conrad from the Astoria 

Formation (Miocene) of Oregon. Both of these species 

are assigned to the Turritella uvasana stock by Merriam 

(1941, p. 43). 

Holotype.-Herewith designated USNM 213991, 

plate 3, figure 16. 
30 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

-·· ...... .......... ........ __ ........ ...... ............. . ........ 

.... ······· 

FIGURE 8.-Growth-line sinus on Turritella pittsburgensis, n. sp. 

Drawing by Anthony D' Attilio. 

Type locality .-USGS 15588. Roadcut on logging road 

along the headwaters of the second main tributary 

entering Coal Creek from the northeast of its junction 

with Pebble Creek. 3,900 feet west of grid 820 and 5,200 

feet south of grid 2,650, Vernonia quadrangle, Pittsburg 

Bluff Formation (middle Oligocene), Oregon. 

Turritella wheatlandensis Clark and Anderson (1938, 

p. 949, pl. 3, figs. 10, 18) from the Wheatland Formation 

(late Eocene or early Oligocene), California, is a much 

larger species (holotype 59 mm high, incomplete, and 24 

mm wide) with a heavy shell. T. wheatlandensis has 

four spiral ribs on the adult whorls whereas T. 

pittsburgensis has six. Although both forms have paired 

anterior ribs that are strongest, the paired spirals are 

stronger on T. wheatlandensis in relation to the other 

spirals than on T. pittsburgensis. 

Turritella oregonensis Conrad from the Astoria 

Formation (Miocene), Oreg. (Moore, 1963, p. 25, pl. 1 

figs. 9-12), is similar in size and shell thickness to T. 

pittsburgensis. It also has prominent paired spirals 

anterior to the middle of the whorl. The paired spirals 

are, however, more prominent and bolder than on T. 

pittsburgensis and occupy a somewhat more posterior 

position. T. oregonensis has a total of no more than four 

spirals, whereas T. pittsburgensis has six on the later 

whorls. 

Turritella porterensis Weaver from the Lincoln Creek 

Formation (late Eocene to early Miocene) of 

Washington does not have the two strong paired anterior ribs, although it does have a pair of primaries 

with a secondary between them. It has more spiral ribs, 

and the whorls are gently and almost evenly rounded. 

Perhaps Turritella wheatlandensis, T. pittsburgensis, 

and T. oregonensis could appropriately be assigned to 

one branch of the T. uvasana stock and T. porterensis 

and T. diversilineata blakeleyensis Weaver (1912, p. 72, 

pl. 11, fig. 85; pl. 6, figs. 64, 67) from the Blakeley 

Formation of Weaver (1912) (late Oligocene or early 

Miocene) in Washington, could be assigned to another 

separate branch (Merriam, 1941, p. 43, fig. 6). 

Localities-USGS 15278, 15457, 15499, 15519, 

15530, 15537, 15588, M3873. 

Occurrence elsewhere-One poorly preserved specimen from the top of the Keasey Formation (late Eocene 

and early Oligocene), near Vernonia, Oreg., may be this 

species (M3864). 

Family EPITONIIDAE 

Genus Opalia Adams and Adams 

Opalia Adams and Adams, 1853, The genera of Recent Mollusca, v. 1, 

p. 223. 

Type species.-By subsequent designation (Cossmann, 1912, Essais de paleoconchologie comparee, v. 9, 

p. 78), Scalaria australis Lamarck. Holocene, Australia. 

Subgenus Dentiscala de Boury 

Dentiscala de Boury, 1886, Monographie des Scalidae vivante et 

fossiles, I, pt. 1, p. xxi. 

Type species.-By monotypy, Turbo crenata Linne, 

1758, Syst. Nat., p. 765. Holocene, Mediterranean and 

Atlantic. Opalia (Dentiscala?) hertleini, n. sp. 

Plate 3, figures 6, 8, 20 

This species is of moderate size with a fairly thick 

shell. It has 12 strong, slightly arcuate axial ribs on the 

last preserved whorl and about 28 spiral threads. The 

axial ribs may be offset at the suture or may be 

confluent. No callus is present. The interspaces are 

wider than the axial ribs. The spiral threads are of 

unequal weight, closely spaced, and cross the axial ribs. 

The spiral threads are microscopically sculptured by 

axial threads that produce a finely reticulate pattern on 

well-preserved portions of shell. The suture is impressed, somewhat overlapping, and sinuous. The 

aperture is not preserved. It has not been possible to 

determine the presence or character of a basal disk. 

Holotype.-Herewith designated USNM 213983, 

plate 3, figure 20. 

Type locality .-USGS 15588. Cut in logging road 

along the headwaters of the second main tributary 

entering Coal Creek from the northeast of its junction 

with Pebble Creek. 3,900 feet west of grid 820 and 5,200 

feet south of grid 2,650, Vernonia quadrangle, Pittsburg 

Bluff Formation (middle Oligocene), Oregon. 

This species most closely resembles the subgenus 

Dentiscala in configuration and primary sculpture. 

However, no punctations were seen on the shell, only 
CLASS GASTROPODA 31 

small preserved patches of microscopically reticulate 

sculpture. Since the outermost shell layer is known to be 

porous and to- decorticate readily, it may be that the 

punctations are absent owing to lack of preservation of 

this layer. 

The only west coast fossil epitonid which this form at 

all resembles is Epitonium (Boreoscala) keaseyense 

Durham (1937, p. 498, pl. 57, fig. 17). It is distinguished 

from E. (B.) keaseyense by its lack of a callus at the 

suture where the axial ribs are joined and in having 

more axial ribs and many more spiral threads than E. 

(B.) keaseyense. Opalia (Dentiscala?) hertleini resembles 

the living form Opalia colimana (Hertlein and Strong) 

which occurs from Santa Cruz, Nayarit, to Manzanillo, 

Colima, Mexico (Keen, 1971, p. 438).1t differs from it in 

having two to four more ribs that are smaller than those 

on 0. colimana. 

Living species in tropical west America are found 

from southern California and the Gulf of California to 

Panama (Keen, 1971, p. 438-440). 

Localities.-USGS 15588, 21612, M3857. 

Family CALYPI'RAEIDAE 

Genus Crepidula Lamarck 

Crepidula Lamarck, 1799, Soc. Hist. Nat. Paris Mem., p. 78. 

Type species .-By monotypy, Patella fornicata Linne. 

Holocene, Atlantic and Gulfcoastsofthe United States. 

Crepidula pileum (Gabb) 

Plate 1, figures 5, 8 

Crypta (Spirocrypta) pileum Gabb, 1864, Geol. Survey California, 

Paleontology, v. 1, p. 137, 228, pl. 29, figs. 2, 3. 

Crepidula pileum (Gabb). Stewart, 1926, Acad. Nat. Sci. Philadelphia 

Proc., v. 78, p. 341-342, pl. 29, figs. 2, 3. Turner, 1938, Geol. Soc. 

America Spec. Paper 10, p. 90, pl. 20, fig. 6. Effi.inger, 1938, Jour. 

Paleontology, v. 12, p. 378. 

Crepidula (Spirocrypta) pileum (Gabb). Clark, 1938, Geol. Soc. 

America Bull., v. 49, p. 701-702, pl. 4, fig. 19. 

Crepidula pileum is a small species. The apex is low 

and does not rise above the shell. The shell is smooth 

except for bunched concentric lines. The internal deck is 

attached along the margins at about the middle of the 

shell with a sinuous free margin. Because part of the 

internal deck is missing on the figured specimen, the 

S-shaped outline of the free deck edge does not show. I 

am indebted to Bruce Welton, Portland State University, who collected and donated the figured specimen. It is the only well-preserved Crepidula in the 

collections; the others are poorly preserved or broken. 

Lectotype.-ANSP 4221 (Stewart, 1926, pl. 29, fig. 3). 

Type locality.-Tejon Pass, Kern County, Calif. (Tejon Formation, early, middle, and late Eocene.) 

Crepidula pileum is distinguished from other species 

of Crepidula by its small size, low apex, and sinuous 

internal deck margin. 

Localities.-USGS 15264, 15310, 15310d; figured 

specimen from road cut on the Vernonia-Scappoose 

road, approximately 2 miles from the junction with 

State Highway 47. Pittsburg Bluff Formation. 

Occurrence elsewhere.-Cowlitz Formation (late 

Eocene) and Gries Ranch Formation (early Oligocene), 

Washington; Coaledo Formation (late Eocene), Oregon; 

Tejon Formation (early, middle and late Eocene), 

California. Family NATICIDAE 

Subfamily NATICINAE 

Genus Cryptonatica Dall 

Cryptonatica Dall, 1892 (1890--1903), Wagner Free Inst. Sci. Trans., v. 

3, pt. 2, p. 362. 

Type species.-By subsequent designation (Dall, 

1909, p. 85), Natica clausa Broderip and Sowerby. 

Holocene, Arctic Ocean to Queen Charlotte Islands. 

Dall proposed Cryptonatica for species with a smooth 

calcareous operculum and an umbilicus entirely filled 

with callus. Tectonatica is generally used for a small 

tropical species (Type: Natica tectula Bonelli) and 

Cryptonatica for a large boreal species. Another criterion that has been used for distinguishing the shells of 

the two forms is that the umbilical callus of the type 

species of Tectonatica does not completely fill the umbilicus (Woodring, 1957, p. 88), whereas inCryptonatica 

clausa it does. In the fossil species Cryptonatica 

oregonensis (Conrad) from the Astoria Formation of 

Oregon, specimens are found representing both types of 

umbilical closure (Moore, 1963, pl. 2, figs. 2, 16). 

Cryptonatica pittsburgensis n. sp. 

Plate 1, figures 9, 12, 13, 15, 16, 18, 19, 23 

Cryptonatica pittsburgensis is small to moderate in 

size (largest specimen: 28 mm high, 23 mm wide); most 

of the specimens are small. The umbilicus is usually 

completely filled with callus (pl. 1, fig. 13) but there are 

rare specimens which have a slight groove behind the 

callus. When the shell exfoliates, only a round umbilical 

plug is left. The spire is small and low, and the whorls 

are evenly rounded without a shoulder. 

Holotype.-Herewith designated USNM 213951, 

plate 1, figure 13. 

Type locality .-USGS 15310h. First large roadcut on 

west side of Scappoose-Vernonia Road, south of cutoff to 

Wilark, Columbia County, Oreg. Pittsburg Bluff 

Formation, middle Oligocene. 

The body whorl of C. pittsburgensis is more inflated 

and is not so high as on Cryptonatica oregonensis 

(Conrad) (Moore, 1963, p. 27, pl. 2, figs. 2-4, 16, 17) from 

the Astoria Formation (Miocene), Oregon. The body 

whorl is less inflated than that of "Natica" weaveri 

Tegland (1933, p. 138-139) from the Gries Ranch (lower 

Oligocene) and Lincoln Creek (late Eocene to early 

Miocene) Formations in Washington. 

Localities-USGS 2714, 5394, 15264, 15264a, 

15264b, 15264e, 15310, 15310a~, 15586, 15588, 18638, 

21612, M3857, M3871, M3872, M3877, M3878. 
32 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

Subfamily POLINICINAE 

Genus Polinices Montfort 

Polinices Montfort, 1810, Conchyliologie systematique, v. 2, p. 223. 

Type species.-By original designation, Polinices 

alb us Montfort ( =Natica mamillaria Lamarck = Natica 

brunnea Link). Holocene, West Indies. 

Polinices washingtonensis (Weaver) 

Plate 1, figures 14, 17, 20-22, 24 

Natica washingtonensis Weaver, 1916a, Washington Univ. (Seattle) 

Pubs. Geology, v. 1, p. 44, pl. 5, figs. 73--76. 

Polinices washingtonensis (Weaver). Clark and Anderson, 1938, Geol. 

Soc. American Bull., v. 49, p. 954, pl. 3 figs. 16, 17. Weaver, 1942, 

Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 337, pl. 68, figs. 

18, 23. Hickman, 1969, Oregon Univ. Mus. Nat. Hist. Bull. 16, p. 

84-85, pl. 11, figs. 12-19. 

Natica lincolnensis Weaver, 1916a, Washington Univ. (Seattle) Pubs. 

Geology, v. 1, p. 44-45, pl. 5, figs. 71, 72. 

Polinices (Polinices) washingtonensis (Weaver) var. lincolnensis 

(Weaver). Weaver, 1942, Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 337-338, pl. 68, fig. 22, pl. 69, figs. 4, 7. 

Polinices washingtonensis is of moderate size with a 

fairly thick shell, moderate spire, evenly rounded body 

whorl, and spire without shoulders. The shell is smooth 

except for bunched radial lines that increase in 

prominence with erosion of the shell. 

Holotype.-CAS 7516. 

Type locality.-Cut along Union Pacific Railway 1 

mile north of Galvin Station, Lewis County, Wash. 

Lincoln Creek Formation, late Eocene to early Miocene. 

Tegland (1933, p. 139), Clark and Anderson (1938, p. 

954), and Hickman (1969, p. 85) thought thatPolinices 

washingtonensis and Polinices lincolnensis were 

probably conspecific. Effinger (1938, p. 377) thought 

that the forms were probably distinct. Weaver (1942, p. 

337-338) considered P. lincolnensis as a variety of P. 

washingtonensis; he believed that P. lincolnensis differed from P. washingtonensis by having the umbilicus 

wide open whereas the umbilicus of P. washingtonensis 

was covered by a heavy callus. He also believed that the 

two forms he described were of possible stratigraphic 

significance. On the basis of a comparison of type 

specimens of rrNatica" washingtonensis Weaver (CAS 

7516) and uNatica" lincolnensis Weaver (CAS 7515A) 

and other available material, it is my belief that they 

belong to one variable species. The specimens that were 

removed from the same piece of rock represent the two 

forms (pl. 1, figs. 17, 20). Therefore it is difficult to 

believe that they might be of stratigraphic significance. 

The degree of closure of the umbilicus is not related to 

the size of the specimen. 

The type specimen of Polinices washingtonensis is 

smaller than that of Polinices washingtonensis lincolnensis. Because the inner edge of the callus lobe is 

broken on the type specimen of P. washingtonensis 

lincolnensis, an erroneous impression is given of the 

extent of coverage of the umbilicus; the umbilical area is 

larger than it is on P. washingtonensis. In the original 

description, the umbilical opening was said to be entirely absent on P. washingtonensis, but it is not entirely absent; the callus does not completely cover the 

umbilical area, there is a funnellike groove behind it. It 

is well known that the variability within species of the 

naticids can be great and that factors such as size, sex, 

and preservation increase this variability. With no 

evidence that the two forms P. washingtonensis and P. 

washingtonensis lincolnensis have different stratigraphic positions, it is illogical to separate them. 

Localities.-VSGS 2714,5394, 15264, 15310, 15310a, 

c-e, g, h, 15588, M3871, M3878. 

Occurrence elsewhere.-Gries Ranch Formation 

(early Oligocene), Quimper Sandstone of Durham 

(1942) (early and middle Oligocene), Lincoln Creek 

Formation (late Eocene to early Miocene), Blakeley 

Formation of Weaver (1912) (late Oligocene and early 

Miocene), Washington; Alsea Formation (early, middle 

and late Oligocene), Tunnel Point Sandstone (middle 

Oligocene), Eugene Formation (early and middle 

Oligocene), Oregon; Wheatland Formation of Clark and 

Anderson (1938) (late Eocene or early Oligocene), upper 

part of San Emigdio Formation (late Eocene to middle 

Oligocene), California. 

Genus Neverita Risso 

Neverita Risso, 1826, Histoire naturelle des principales production de 

l'Europe Meridionale, v. 4, p. 149. 

Type species.-By monotypy, Neverita josephinia 

Risso. Holocene, Mediterranean Sea. 

Subgenus G1ossaulax Pilsbry 

Glossaulax Pilsbry, 1929, Nautilus, v. 42, p. 113. 

Type species .-Holotype by original designation, 

Neverita reclusiana (Deshayes). Holocene, southern 

California, and throughout Gulf of California to Tres 

Marias Islands, Mexico (Keen, 1971, p. 482). 

Neverita (Glossaulax) thomsonae Hickman 

Plate 2, figures 1-15 

Neverita (Glossaulax) thomsonae Hickman, 1969, Oregon Univ. Mus. 

Nat. Hist. Bull. 16, p. 84, pl. 11, figs. 20-23. 

Neverita thomsonae is moderate to large in size 

(largest specimen 47 mm wide and 39 mm high, incomplete); it has a thick shell, large globose body whorl, 

and a small, low spire. The suture is overlapping and no 

tabulation is present. The shell is usually smooth, but 

on some specimens (pl. 2, fig. 15) spiral lines can be seen 

near the base of the body whorl. The shape and size of 

the umbilical callus is variable, depending largely on 

the size of the entire shell. The largest shells have a very 

thick callus whereas the smallest shells have a callus of 

moderate thickness. The callus completely fills the 

umbilical area and is grooved. The posterior portion of 

the bifid callus is the largest and is rounded and 

pluglike; the anterior portion is small and triangular. 
CLASS GASTROPODA 33 

The outer lip protrudes a few millimetres beyond the 

callus. 

Holotype.-VO 27366. Paratypes: UO 27367-27372. 

Type locality.-VO 2567. In well indurated 

brownish-gray tuffaceous sandstone and siltstone, east 

side of Oregon State Highway 4 7, 2 miles north of 

junction with Pittsburg-Scappoose Road. Nlhsec. 23, T. 

5 N., R. 4 W., Vernonia quadrangle. Type Pittsburg 

Bluff Formation (middle Oligocene), Oregon. 

N. thomsonae is a much larger and heavier shelled 

form than any of the Eocene species of Neve rita that I 

have examined. It is larger than Neuerita jamesae 

Moore from the Astoria Formation (Miocene), Oregon 

(Moore, 1963, p. 28) and has a much larger and heavier 

umbilical callus. 

Neuerita lives intertidally on sandbars where it preys 

on clams (Keen, 1971, p. 482) and in lagoons and shallow bays (McLean, 1969, p. 37). 

Localities.-VSGS 2714, 5394, 15264, 15310, 15310a, 

d-g, j, 15311, 15312, 15588, M3857, M3858, M3871, 

M3878. 

Occurrence elsewhere.-Eugene Formation (early 

and middle Oligocene), Oregon; Wygal Sandstone 

Member of the Temblor Formation (late Oligocene), 

California. 

Subfamily SININAE 

Genus Sinum Roding 

Sinum Roding, 1798, Museum boltenianum, pt. 2, p. 14. 

Type species .-By subsequent designation (Dall, 

1915, U.S. Natl. Mus. Bull. 90, p. 109),Helix haliotoidea 

Linne. Holocene, western Pacific Ocean(?). Subgeneric 

assignments are discussed by Addicott (1970c, p. 70). 

Sinum aff. S. obliquum (Gabb) 

Plate 1, figures 10, 11 

Two small specimens ofSinum (largest: 10 mm high, 

9.3 mm wide) were collected from the Pittsburg Bluff 

Formation. Sinum aff. S. obliquum (Gabb) is thin shelled and has a small low spire and spiral cords of equal 

size with finer cords present in some but not all of the 

interspaces. The secondary cords are more numerous 

near the round shoulder. Of the described west American species, it resembles Sinum obliquum (Gab b) (1864, 

p. 109, 225, pl. 21, fig. 112) from the Eocene and 

Oligocene of the Pacific coast, but it seems to have a 

higher body whorl and a more ovate and perpendicular 

aperture. It is much smaller than Sinum scopulosum 

(Conrad)(1849,p.727,pl.19,figs.6,6a;Moore,1963,p. 

29, pl.1, figs. 2, 3, pl. 2, figs. 20, 21) from the Miocene and 

Pliocene of the Pacific coast and seems to have a less 

inflated body whorl. It has not been possible to determine, on the basis of the two specimens available, if 

this is a new species. 

Localities.-VSGS 15264, 15264e. 

Occurrence elsewhere.-Of Sinum obliquum (Gabb): 

Cowlitz (late Eocene) and Gries Ranch (early Oligocene) 

Formations, Washington; Keasey (late Eocene and 

early Oligocene) and Eugene (early and middle 

Oligocene) Formations, Oregon; Tejon Formation (early, middle and late Eocene), California. I 

Family NEPTUNEIDAE 

Genus Eosiphonalia Ruth 

Eosiphonalia Ruth, 1942, California Univ. Pubs., Dept. Geol. Sci. 

Bull., v. 26, no. 3, p. 288. 

Type species.-By original designation, Strepsidura 

washingtonsis Weaver, Lincoln Creek Formation (late 

Eocene to early Miocene), Washington. 

As noted by Ruth (1942, p. 288), Eosiphonalia is 

distinguished from Siphonalia by its lower spire, shorter and less recurved canal, biangulate body whorl that 

is more nodose, and lack of lirations on the inner lip. 

Eosiphonalia is an Oligocene genus endemic to 

California, Oregon, Washington, and Alaska. 

Eosiphonalia oregonensis (Dall) 

Plate 4, figures 1-9 

Strepsidura oregonensis Dall, 1909, U.S. Geol. Survey Prof. Paper 59, 

p. 51, pl. 3, fig. 6. 

Siphonalia (Eosiphonalia) oregonensis Dall. Ruth, 1952, California 

Unit. Pubs., Dept. Geol. Sci. Bull., v. 26, p. 290, pl. 47, fig. 20. 

Siphonalia oregonensis (Dam. Weaver, 1942, Washington Univ. 

(Seattle) Pubs. Geology, v. 5, p. 439, pl. 86, fig. 12. 

Eosiphonalia oregonensis is of moderate size; the 

largest s specimen is 39.2 mm high and 27.5 mm wide 

(pl. 4, figs. 1, 3). The spire is low, making up a quarter of 

the total shell height, is tabulate, and has nodes on the 

shoulders. The body whorl is large, inflated, and 

sculptured usually by three or four, but sometimes five, 

prominent spirals that are separated by angulations. 

The spiral on the shoulder has nodes, and usually the 

next two anterior spirals are also noded. The entire shell 

is sculptured by fine spirals of approximately equal 

strength. The siphonal canal is deeply notched and 

slightly recurved. The area betw~en the last strong 

spiral on the body whorl and the canal is moderately to 

deeply impressed. 

Holotype.-VSNM 107395, plate 4, figures 4, 6. 

Type locality.-VSGS 2714. In fine-grained 

brownish-gray sandstone in roadcut at Pittsburg Bluffs, 

Columbia County, Oregon. Pittsburg Bluff Formation, 

middle Oligocene. 

Two described fossil species resemble E. oregonensis: 

E. washingtonensis (Weaver) (1916a, p. 48--49, pl. 5, 

figs. 81-83) from the Lincoln Creek Formation (late 

Eocene to early Miocene), Washington, and E. californica (Arnold) (1908, p. 370-371, pl. 33, fig. 12) from the 

San Lorenzo Formation (late Eocene to middle 

Oligocene), California. E. washingtonensis is a smaller 

form with a higher spire and stronger nodes, some of 

which are almost spinose. It has two or three raised 
34 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

spirals with nodes on the body whorl; the finer spirals 

are more prominent than on E. oregonensis. Weaver 

(1942, p. 439) said that E. washingtonensis has a 

nonornamented band just posterior to the siphonal 

fasciole at the end of the canal that distinguishes it from 

E. oregonensis; such an area is not discernible on the two 

specimens examined. 

E. californica is a higher spired form, has stronger 

nodes than E. oregonensis, and has two angulations on 

the body whorl. 

Localities.-USGS 15264, 15310, 15310a, d, 15532, 

15537, 15588,~3857, ~3871. 

Occurrence elsewhere.-Poul Creek Formation 

(Oligocene and Miocene), Yakataga district, Gulf of 

Alaska. 

Genus Bruclarkia Trask 

Bruclarkia Trask in Stewart, 1926, Acad. Nat. Sci. Philadelphia Proc., 

v. 78, p. 397, 399. 

Type species .-By original designation, Clavella 

gravida Gabb. Lower Miocene, Contra Costa County, 

Calif. 

Bruclarkia is an endemic Pacific coast genus; it first 

appears in the early Oligocene and becomes extinct 

before the end of the ~iocene. Its known geographic 

range is from California north to Alaska. Vokes (1939, 

p. 138) suggests that Bruclarkia may have developed 

from the Eocene genus Umpquaia (Turner, 1938, p. 79). 

The degree of development of nodes and spines is not 

believed to be a specific character in Bruclarkia but 

rather to usually be an expression of variability within 

a species (~oore, 1963, p. 36). Exceptions may be found, 

of course, where there is a relation between degree of 

sculpture and stratigraphic occurrence. Characters that 

have been found to be valid in separating species of 

Bruclarkia are the configuration and extent of development of the shoulder on the body whorl, the 

number and spacing of the strong spiral cords on the 

body whorl, and the height of the spire in relation to the 

size of the body whorl. 

Bruclarkia columbiana (Anderson and Martin) 

Plate 3, figures 1-5, 21-23 

Agasoma columbianum Anderson and Martin, 1914, California Acad. 

Sci. Proc., ser. 4, v. 4, p. 73, pl. 5, figs. 6a, 6b. 

Bruclarkia columbiana (Andeeson and Martin). Weaver, 1942, 

Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 443, pl. 87, figs. 7, 

8. Durham, 1944, California Univ. Pubs., Dept. Geol. Sci. Bull., v. 

27, p.173. Hickman, 1969, Oregon Univ. Mus. Nat. Hist. Bull.16, p. 

94, pl. 13, figs. 12, 13. 

Bruclarkia columbiana is the largest species in the 

genus; individuals grow to a height of 60 mm and a 

width of 48 mm. The spire is low, about one-fourth the 

height of the body whorl, and the body whorl is greatly 

inflated. The species has three prominent spiral cords on 

the body whorl; the one on the shoulder and the one 

below it are nodose to slightly spinose; the third and 

most anterior spiral may be smooth or slightly noded. 

One noded prominent spiral may be present on the 

whorls of the spire at or just above the suture, which is 

strongly overlapping. On well-preserved specimens, a 

collar, sculptured by prominent spirals, is present at the 

suture (pl. 3, fig. 5), but this collar apparently exfoliates 

readily, as it is rarely preserved, even on specimens 

with the remainder of the shell intact. The entire surface of the shell is sculptured by subrounded spiral cords 

of varying strength that may be separated by finer 

secondary cords. The siphonal canal is long and recurved. 

Holotype.-CAS 155. Paratype CAS 156. 

Type locality.-At Pittsburg Bluffs, Columbia County, Oreg. Pittsburg Bluff Formation (middle Oligocene), 

Oregon. 

The holotype of B. columbiana is 56 mm high and 40 

mm wide, bears three nodose spirals on the body whorl, 

and has an overlapping, sinuous, swollen and collared 

suture. There are no nodes on the spire. The paratype of 

B. columbiana bears three spirals on the body whorl. 

These spirals are slightly spinose over two-thirds of the 

body whorl, but smooth on one-third of the body whorl 

near the aperture. The suture on the body whorl of the 

paratype is sinuous, overlaps the spire, and is strongly 

collared near the aperture. The whorls of the spire bear 

nodes on the spiral just above the suture on the 

paratype; they are smooth on the holotype. 

Specimens of B. columbiana from USGS locality 

15310 have much stronger nodes and are generally 

larger than specimens from other localities within the 

Pittsburg Bluff Formation. 

B. columbiana is distinguished from other described 

species of Bruclarkia by the constant 40° slope from the 

suture to the shoulder margin of the body whorl, the low 

spire, the strongly inflated body whorl, and the two 

prominent, noded spiral cords on the body whorl, one on 

the edge of the shoulder and the other below it. 

Durham (1944, p. 173) reports B. columbiana from the 

Molopophorus gabbi, Turritella olympicensis, and T. 

porterensis Zones of northwestern Washington. 

Localities.-USGS 2415, 2714, 2715, 2721, 5394, 

15264, 15264a, 15310, 15310a-c, e, ~j, 15312,15316, 

15499, 15532, 15586, 15588, 18638, M3858, ~3871, 

~3872, ~3877, ~3878. 

Occurrence elsewhere .-Quimper Sandstone of Durham (1942) (early and middle Oligocene), ~arrowstone 

Shale (early Oligocene), and Lincoln Creek Formation 

(late Eocene to early Miocene), Washington; Alsea 

Formation (early to late Oligocene), upper part of the 

Eugene Formation (middle Oligocene), and Tunnel 

Point Sandstone (middle Oligocene), Oregon; Cymric 

Shale Member of the Temblor Formation (middle 

Oligocene), California. 
CLASS GASTROPODA 35 

Family BUCCINIDAE? 

Genus Molopophorus Gabb 

Molopophorus Gabb, 1869, California Geol. Survey, Paleontology, v. 

2,p. 156-157,219, pl. 26,fig. 36. 

Type species.-By monotypy, Bullia (Molopophorus) 

striata Gabb. Tejon Formation, upper Eocene, 

California. 

Molopophorus is an endemic Pacific coast genus 

appearing in the Eocene and becoming extinct by the 

end of the Miocene. It is found in Alaska, Washington, 

Oregon, and California, and is particularly common in 

the Pittsburg Bluff Formation. 

Molopophorus gabbi Dall 

Plate 5, figures 1-22 

Molopophorus gabbi Dall, 1909, U.S. Geol. Survey Prof. Paper 59, p. 

45, pl. 3, fig. 8. Anderson and Martin, 1914, California Acad. Sci. 

Proc., ser. 4, v. 4, p. 78, pl. 6, figs. 5a, 5b. Weaver, 1942, Washington 

Univ. (Seattle) Pubs. Geology, v. 5, p. 466-467, pl. 90, figs. 4, 6. 

Molopophorus biplicatus quadranodosum Weaver, 1912, Washington 

Geol. Survey Bull. 15, p. 75--76, pl. 11, figs. 91-93; pl. 14, fig. 122. 

Molopophorus gabbi is moderate in size (largest 

specimen 30 mm high and 20 mm wide); it has a rather 

thin shell, inflated body whorl, and short, deeply 

notched, siphonal canal. The most distinctive character 

of the species is its marked variation in body whorl 

sculpture. Usually the sculpture consists of four 

prominent spiral cords. Starting at the posterior end, 

the first three are equally spaced and the fourth has only 

half as much space separating it from the third spiral 

(pl. 5, figs. 10, 11, 16). On some specimens (pl. 5, figs. 8, 

9), the four prominent spiral cords are equally spaced, 

and on the other specimens only three spiral cords are 

present (pl. 5, fig. 15). The spirals may be crossed by 

axial lines that form nodes (pl. 5, fig. 20) or spines (pl. 5, 

fig. 8) at the juncture or that may form axial ribs (pl. 5, 

fig. 12). The suture is sinuous and the collar overlaps the 

spire; more than one-third of the body whorl immediately below the suture is unsculptured. Immature 

forms lack the large unsculptured area on the body 

whorl and are usually more strongly sculptured over the 

rest of the shell. 

Type.-VSNM 107377 (pl. 5, figs. 19, 22) is herewith 

designated the lectotype. This is the specimen originally figured by Dall (1909, pl. 3, fig. 8) and represents 

the smooth form. A strongly sculptured specimen in 

Dall's type lot is assigned USNM 214016 (pl. 5, fig. 21). 

The remaining specimen in the type lot has been assigned USNM 214015. 

Type locality.-VSGS 2714. Pittsburg, Columbia 

County, Oreg. Pittsburg Bluff Formation, middle 

Oligocene. 

The lectotype (ANSP 4340) of Molopophorus biplicatus (Gabb) 1866, p. 9, pl. 2, fig. 14), from the San 

Ramon Sandstone (early Miocene?) in California, has a 

less inflated body whorl and a higher spire than M. 

gabbi. Its collar is not so strongly overlapping and 

prominent, nor does it have as large a concavity below 

the collar on the body whorl as M. gabbi. The three 

specimens in the type lot are not too well preserved, but 

they do show axial ribs on the body whorl that may 

become obsolete toward the aperture. Clark (1918, p. 

17 4) considered M. gabbi and M. biplicatus to be so 

closely related that he considered M. gabbi to be a 

subspecies of M. biplicatus. The two specimens figured 

by Clark (1918, pl. 6, figs. 7a, 7b) were collected from the 

San Ramon Sandstone and compare well with M. 

biplicatus. 

Weaver(1912,p. 75-76,pl. 11,figs.91-93,pl. 14,fig. 

122) described Molopophorus biplicatus quadranodosum from the middle Oligocene of Washington. 

Weaver (1942, p. 469) thought that the four prominently noded spiral ribs on the middle of the body whorl 

distinguished this subspecies. The large number of 

specimens of M. gabbi now available show that this 

ornamentation is common on M. gabbi. The holotype of 

M. biplicatus quadranodosum has been lost. 

Molopophorus dalli Anderson and Martin (1914, p. 

78, pl. 6, figs. 7a, 7b) lacks the strong sculpture of M. 

gabbi and never has nodes or spines, although it may be 

cancellate or beaded (Hickman, 1969, p. 91, pl. 13, fig. 

1). M. dalli was originally collected near Clatskanie, 

Oreg., in rocks that are now assigned to the Gries Ranch 

Formation (early Oligocene) (Warren and others, 1945). 

Durham (1944, p. 170) reports M. dalli from his 

Molopophorus gabbi Zone, specifically from a locality in 

the Quimper Sandstone of Durham (1942) (middle and 

late Oligocene), Washington. Hickman (1969, p. 91) 

reports the rare occurrence of M. dalli in the lower and 

middle Eugene Formation, which she assigns to the 

early Oligocene. She also collected some specimens ofM. 

dalli from the Salem area, in beds questionably referred 

to the upper (middle Oligocene) part of the Eugene 

Formation. M. dalli has not been found in any of the 

collections from the Pittsburg Bluff Formation at hand, 

and it seems probable that M. dalli may be restricted to 

the early Oligocene. 

Molopophorus lincolnensis Weaver (1916a, p. 50, pl. 

4, figs. 60, 61), a common species in the Lincoln Formation (late Eocene to early Miocene) in Washington, is 

distinguished from M. gabbi by its smaller size and lack 

of spiral sculpture. The sculpture consists only of axial 

ribs. 

Localities.-VSGS 2415, 2714, 5394, 15264, 15264a, 

e, d, 15278, 15310, 15310a-j, 15311, 15312, 15532, 

15544, 15586, 15588, 18638, 18779, M3858, M3860, 

M3871, M3877, M3878. 

Occurrence elsewhere .-Quimper Sandstone of 

Durham (1942) (early and middle Oligocene), reported 

by Weaver (1916d, p. 39) from the Lincoln Creek 
36 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

Formation (late Eocene to early Miocene), Washington; 

Gries Ranch Formation (early Oligocene), USGS 5210, 

Tunnel Point Sandstone (middle Oligocene), Oregon; 

San Lorenzo Formation (late Eocene to middle 

Oligocene), California (Clark, 1915, p. 18). 

Family FUSINIDAE 

Genus Priscofusus Conrad 

Priscofusus Conrad, 1865, Am. Jour. Conchology, v. 1, p. 150. 

Type species .-By subsequent designation (Cossman, 

1901, Essais de paleoconchologie comparee, p. 8), Fusus 

geniculus Conrad. Astoria Formation, Miocene, Oregon. 

Priscofusus is an endemic Pacific coast genus appearing in the Paleocene and becoming extinct in the 

Pliocene. Its geographic range is Alaska to California. 

Priscofusus stewarti (Teg1and) 

Plate 3, figures 17-19 

Fusinus (Priscofusus) stewarti Tegland, 1933, California Univ. Pubs., 

Dept. Geol. Sci. Bull., v. 23, p.129-30, pl.12, figs. 4-8. Weaver, 1942, 

Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 486-487, pl. 93, 

figs. 3, 4, 10, 14. 

Two small specimens of Prisco{ us us stewarti are in 

the collections; one is almost complete; the other has 

only the spire preserved. P. stewarti is slender in outline with small somewhat elongate nodes one-third the 

whorl height above the suture. The surface is sculptured 

with closely spaced subrounded spiral ribs of slightly 

different widths; between the ribs there may be a spiral 

thread. 

Holotype .-UCMP 32238. 

Type locality.-Restoration Point, opposite Seattle, 

Wash. Blakeley Formation of Weaver (1912) (late 

Oligocene and early Miocene). 

Priscofusus chehalisensis (Weaver) (1912, p. 78-79, 

pl. 6, figs. 65, 66) is larger and has a much higher and 

slimmer spire than P. stewarti. 

Localities.-VSGS 15264, 15588, M3871. 

Occurrence elsewhere .-Poul Creek Formation (middle Oligocene to early Miocene), Yakataga district, Gulf 

of Alaska; Blakeley Formation (late Oligocene and 

early Miocene), Washington; Alsea Formation [early to 

late Oligocene]. 

Family F ASCIOLARIIDAE 

Genus Perse Clark 

Perse Clark, 1918, California Univ. Dept. Geology Bull., v. 11, p. 179. 

Type .-By original designation, Perse corrugatum 

Clark. San Ramon Sandstone (early Miocene?), California. 

Perse is an endemic west coast genus found in Eocene 

to Miocene rocks in California, Oregon, and 

Washington. It first appears in the late Eocene and 

becomes extinct at the end of the early Miocene, or the 

end of the Oligocene, depending upon the age assignment given to the Blakeley and San Ramon 

Formations ofWashington and California, respectively. 

Stewart (1926, p. 401-402) proposed a new genus, 

Whitneyella and designatedHemifusus washingtoniana 

Weaver(1912,p.46-47,pl.2,fig. 11,notfig. 12)asthe 

type species. Stewart considered the type specimen of 

Perse corrugatum to be generically distinct from the 

group represented by Hemifusus washingtoniana, 

although Clark had placed H. washingtoniana in his 

genus Perse. In 1938, Clark (p. 718-719) placed 

Whitneyella in synonymy with Perse, saying that the 

anterior end of the canal of the poorly preserved type 

specimen of P. corrugatum was broken off and that the 

original illustration was therefore misleading. 

Examination of the type specimen of P. corrugatum 

shows it to be congeneric with Hemifusus washingtoniana, and this group is therefore assigned the oldet 

name Perse. 

Perse is usually of small to moderate size, it has a thin 

shell that has a long, slightly recurved canal. The anterior end of the canal is very narrow, and specimens are 

rarely collected with the canal intact. On broken 

specimens, the narrowness of the canal may lead one to 

suppose erroneously that it would have been about half 

of its actual length. Slightly rounded to flat-topped spiral cords form the predominant sculpture. These cords 

may have weak nodes or axial swellings. The suture is 

collared and overlaps the spire; the collar varies in 

strength and may be smooth or sculptured by spiral 

cords. The spire is usually low and less sculptured than 

the body whorl. A pronounced concavity occurs between 

the suture and the maximum inflation of the whorls; 

this concavity is particularly well developed on the body 

whorl. 

Perse pittsburgensis Durham 

Plate 6, figures 1, 4, 6, 7, 9, 12-14, 18-20 

Perse pittsburgensis Durham, 1944, California Univ. Pubs., Dept. 

Geol. Sci. Bull., v. 27, p. 175, pl. 16, figs. 2, 4. 

Perse pittsburgensis is a small- to moderate-sized 

species (largest specimen: 27 mm high, 15 mm wide) 

with a thin shell. The suture is collared and overlaps the 

spire; the collar usually bears two closely spaced, flat 

spirals. The spire and body whorl are sculptured by 

slightly rounded, straplike spiral cords that are generally smooth but may be slightly noded. The spirals are 

most strongly developed on the maximum swelling of 

the whorls, and -all are separated by interspaces that 

may be equal to one and one-halftimes the width of the 

spirals. The wider interspaces may bear a secondary 

spiral thread. A concavity is present on the body whorl 

between the suture and the first strong spiral just above 

the maximum point of inflation; it generally bears 

spirals of somewhat smaller size than on the rest of the 

body whorl. The whorls of the spire are roundly 

tabulate. The siphonal canal is long, very narrow, and 

slightly recurved (pl. 6, figs. 1, 4). 
CLASS GASTROPODA 37 

Holotype.-VCMP 35409. 

Type locality.-ln bluffs along road along the east side 

of the highway along the Nehalem River, about 21 miles 

south of Mist and 0.2 mile north of junction with road to 

St. Helens, and 0.25 mile north of bridge. Pittsburg 

Bluff Formation (middle Oligocene), Oregon. 

P. pittsburgensis varies considerably in degree of 

sculpture, but it always bears straplike spiral cords and 

has a characteristic outline with a low spire and an 

inflated body whorl bearing a deep but relatively short 

sinus. P. pittsburgensis vernoniensis has a longer 

concavity between the suture and the periphery, and 

bears, if any, only one strong strap like spiral on this 

concavity. The sculpture usually consists of fine spiral 

threads. The entire shell is slimmer and the spire is 

higher than that of P. pittsburgensis. 

Perse olympicensis Durham (1944, p. 174-175, pl. 16, 

fig. 1), from the early Oligocene Molopophorus 

stephensoni Zone, does not bear the straplike spirals of 

P. pittsburgensis. P. olympicensis quimpersensis 

Durham (1944, p. 175, pl. 16, figs. 5, 6), from the middle 

Oligocene Molopophorus gabbi Zone, is distinguished 

by having longitudinal ribs. 

Localities.-VSGS 2714, 2722, 5394, 15264, 

15264b,c,e,15278,15310,15310b,c,e-j,15311,15312, 

15519, 15537, 15545, 15586, 15588, 18638, 18779, 

M3856, M3857, M3858, M3866, M3868, M3871, cf. 

M3872, M3877, M3878. 

Occurrence elsewhere.-Alsea Formation (early, 

middle, and late Oligocene), Oregon. 

Perse pittsburgensis vernoniensis, n. subsp. 

Plate 6, figures 2, 3, 5, 8, 10, 11, 15-17 

Perse pittsburgensis vernoniensis is fusiform in 

outline, is of moderate size (largest specimen: 29 mm 

high, 16 mm wide), and has a higher spire than is usual 

for Perse. It is sculptured with rounded spiral cords 

which may be noded with axial swellings (pl. 6, figs. 10, 

17), noded without axial swellings (pl. 6, fig. 16), or 

fairly smooth (pl. 6, figs. 2, 3). Secondary cords of about 

half the width of the primaries may be present in the 

interspaces, but their occurrence and distribution is 

random. The interspace may be two to three times as 

wide as the spiral cord. Fine spiral threads are present 

on the sinus of the body whorl and on the sinus of the 

spire whorls, if such a sinus is present. The canal is very 

long, slender, and slightly recurved; the entire canal is 

not preserved on any specimen. The inner lip is lirate; 

the suture is overlapping and collared and the collar 

bears one or two spiral cords. Below the collar is a sinus; 

it is strongly developed on the body whorl, occasionally 

shows on the two preceding whorls, but is never present 

on the first three whorls. The sinus is always sculptured 

by fine spiral threads and may also bear one strong 

spiral cord. 

Holotype.-VSNM 214017 is herewith designated the 

holotype (pl. 6, figs. 5, 8). 

Type locality.-VSGS 15588. Cut in logging road 

along the headwaters on the second main tributary 

entering Coal Creek from the northeast of its junction 

with Pebble Creek, 3,900 feet west of grid 820 and 5,200 

feet south of grid 2,650, Vernonia quadrangle. Pittsburg 

Bluff Formation (middle Oligocene), Oregon. 

The shape and sculpture distinguish P. pittsburgensis 

vernoniensis, although, as can be seen on plate 6, the 

sculpture is variable. The spire is higher, the sinus is 

less sculptured and more pronounced, and the spiral 

cords are finer and farther apart than on Perse pittsburgensis; P. pittsburgensis vernoniensis, has a longer 

concavity between the suture and the maximum swelling of the body whorl, and bears, if any, only one strong 

straplike spiral on this concavity. The sculpture consists usually of fine spiral threads. The entire shell is 

slimmer than that of P. pittsburgensis. 

Perse lincolnensis (Van Winkle) (1918, p. 89-90, pl. 7, 

fig. 10) is higher spired than P. pittsburgensis vernoniensis with finer spiral sculpture that bears nodes or 

spines. 

Perse olympicensis Durham (1944, p. 174-175, pl. 16, 

fig. 1) does not bear straplike spirals like P. 

pittsburgensis vernoniensis does, and P. olympicensis 

quimpersensis Durham (1944, p. 175, pl. 16, figs. 5, 6) is 

distinguished by longitudinal ribs. 

P. pittsburgensis vernoniensis occurs at only eight 

localities in the Pittsburg Bluff Formation but is very 

abundant at these localities and occurs with P. 

pittsburgensis at many of them. 

Localities.-VSGS 2714, 15264, 15536, 15588, 18779, 

21612, M3871, M3872, M3878. 

Family TURRIDAE 

Subfamily TURRICULINAE 

Genus Aforia Dall 

Aforia Dall, 1889, Mus. Comp. Zool. Bull. 18, p. 99. 

Type species. -By original designation, Pleurotoma 

circinata Dall. Holocene, North Pacific. 

The known fossil occurrences of Aforia are in the 

Pliocene of Japan, the Oligocene to Pliocene of 

Washington, the Oligocene and Miocene of Oregon, and 

the Oligocene or Miocene of California (Powell, 1966, p. 

44; Javidpour, 1973, p. 197). 

Aforia campbelli Durham 

Plate 7, figure 22 

Aforia campbelli Durham, 1944, California Univ. Pubs., Dept. Geol. 

Sci. Bull., v. 27, p. 183-184, pl. 14, fig. 4. Javidpour, 1973, Veliger, v. 

15,p. 199-200,figs. 1,6, 10. 

Aforia clallamensis (Weaver) subsp. wardi (Tegland). Weaver, 1942, 

Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 516-517, in part, 

pl. 97, fig. 10, not pl. 96, fig. 6. 

Six whorls of the spire of one specimen are preserved 

as an external cast of Aforia campbelli. A rubber im-
38 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

pression that was made from it is illustrated in plate 7, 

figure 22. Aforia campbelli is a large species, 

pagodiform in outline; it has a sharp carina just above 

the suture. The whorl is concave above the carina and 

deeply concave below it. The sinus is deep and broadly 

U-shaped and is located in the middle of the shoulder 

above the carina. The shell seems to have been spirally 

sculptured below the carinae. 

Holotype.-VCMP 14961. 

Type locality.-A1636. Type ~~Porter" Bluffs along 

northeast side of highway beginning at a point 270 

yards southeast of first exposure southeast of Porter 

Station and extending 180 yards. Grays Harbor County, 

Wash. Middle Oligocene, Lincoln Creek Formation. 

A. campbelli has a slimmer spire and higher shoulder 

above the angulation than A. wardi (Tegland, 1933, p. 

124, pl. 10, figs. 5-8), and the angulation is closer to the 

suture than on A. wardi. A. addicotti Javidpour (1973, 

p. 201, figs. 8, 12) has the angulation closer to the middle 

of the whorl and does not have as deep a concavity below 

the angulation as A. campbelli. A. clallamensis 

(Weaver, 1916a, p. 52, pl. 4, fig. 59) has the angulation 

near the middle of the whorl; the shoulder above the 

angulation is not so high nor so concave as on A. 

campbelli and the spire is slimmer. A. clallamensis does 

not have a deep concavity beneath the angulation. 

Javidpour (1973, p. 196-199) has discussed the 

phylogenetics of the six species of Aforia reported from 

the west coast of North America. To her record should be 

added the occurrence of A. campbelli in the Pittsburg 

Bluff middle Oligocene of northwestern Oregon and of 

A. clallamensis (Weaver) in the Astoria Formation, 

Miocene, of the Newport area, Oregon (Moore, 1963, p. 

47, pl. 10, figs. 16, 18). 

Locality.-VSGS 15519. 

Occurrence elsewhere.-Lincoln Formation (late 

Eocene to early Miocene), Washington. 

Subfamily TURRINAE? 

Genus Taranis Jeffreys 

Taranis Jeffreys, 1870, Ann. Mag. Nat. Hist., ser. 4 (5), p. 447. 

Type species.-By monotypy, Trophon morchi Maim. 

Holocene, North Atlantic. 

Taranis has a very small, ovate-biconic, predominantly medially angulate and spirally keeled shell. The 

protoconch is paucispiral, of barely two whorls, papillate to slightly globose, superficially smooth, but it has a 

microscopic sculpture of closely spaced stippled spiral 

lirae. The sinus is shallow; its apex is at the peripheral 

angle or major keel; and its angles of approach are 

unequal-steep and straight above, protractively 

arcuate below. The pillar is abruptly twisted at the 

beginning of a short shallowly notched anterior canal. 

The subfamily position of Taranis is problematic, but 

based on the type of sinus, the apex of which is 

peripheral, the genus is provisionally placed in the 

Turrinae (Powell, 1966, p. 55). 

The known fossil occurrences of Taranis are in the 

Pleistocene of England, Sicily, California, and New 

Zealand; the Pliocene of Italy; the Oligocene and 

Miocene of Oregon; and the Miocene of California. 

Taranis columbiana (Anderson and Martin) 

Plate 7, figures 2, 3, 5-8, 16, 37 

Drillia columbiana Anderson and Martin, 1914, California Acad. Sci. 

Proc., ser. 4, v. 4, p. 94, pl. 7, figs. 4a, 4b. Not Drillia columbiana 

Anderson and Martin of Adegoke, 1969, California Univ. Pubs. 

Geol. Sci., v. 80, p. 192, pl. 13, fig. 10. 

Thesbia columbiana (Anderson and Martin). Weaver, 1942, 

Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 537, pl. 99, fig. 13. 

Taranis columbiana has a rather thick shell and a 

moderately high spire. The sinus is shallow, U-shaped, 

and confined to the keel with almost equal angles of 

approach. The angles are perhaps a bit steeper above 

than below the sinus. The protoconch consists of a little 

more than one and one-half rounded, smooth whorls (pl. 

7, fig. 8). At the apex is a twisted, recurved, hooklike 

process that is centrally located. This process forms a 

spur off the protoconch, rather than from the tip of the 

last whorl, and looks as if it were the columella protruded from the center. The body whorl is small and 

canal is short, recurved, and slightly notched. 

Holotype.-CAS 231; paratype CAS 232. 

Type locality.-Northwest Oregon. This is the locality 

cited by Anderson and Martin (1914, p. 94) and agrees 

with the label on the type specimens. The locality cited 

by Weaver (1942, p. 537), ~~(CAS 65) West bank of small 

canyon one and one-fourth miles northeast of Barker's 

Ranch house in Kern County, California" is in error. In 

addition to checking the label with the holotype of 

~~Drillia" columbiana, the late Leo G. Hertlein, California Academy of Sciences, kindly checked the collection 

from locality CAS 65 and found no specimen labelled 

ffD" columbiana. Presumably the type specimens of 

ffDrillia" columbiana were collected from the Pittsburg 

Bluff Formation near Vernonia, Oreg. 

Twenty specimens that are well enough preserved to 

show shell sculpture are in the collections. These 

specimens show three different forms of sculpture, and 

specimens of each type are present at a single locality 

(M3871). On the smooth-keeled form (pl. 7, figs. 6, 16) 

the keel is smooth, straplike, slightly rounded, and not 

sculptured. There are no spirals above or below the keel 

on the spire. There is no spiral sculpture above the keel 

on the body whorl. Below the keel a strong spiral forms 

-an angulation on the body whorl and above the 

angulation are one or two fine spirals. Below the second 

strong spiral is a weaker but still strong spiral and 

beneath this weaker one are eight fine spirals of equal 

strength. On the intermediate form (pl. 7, fig. 37) the 

keel on the early whorls is thin and smooth; the keel on 
CLASS GASTROPODA 39 

the later whorls is again straplike but bears three to 

four spiral cords. The whorls have a ridgelike collar 

bearing one or two spiral threads. Between the collar 

and the keel may be an additional spiral thread. Below 

the keel on the whorls of the spire is a fairly prominent 

spiral cord. Below the keel on the body whorl are three 

equally spaced smooth spiral cords followed by about 

seven or eight finer, equally spaced spirals. On the 

sculptured-keeled form (pl. 7, fig. 5), the keel spiral is 

thin and rather pointed; above the keel are three fine 

spirals and on the collar one stronger spiral and one fine 

spiral. Above the keel, half way between the keel and 

the suture, is a strong, sharply pointed spiral and below 

it, right at the suture, is a smaller, more rounded spiral. 

The keel of the body whorl is formed by one sharply 

pointed spiral above which are three closely spaced finer 

spirals and one spiral on the collar. Below the keel are 

three strong equally spaced spirals followed by eight 

closely spaced finer spirals. Given only the smoothkeeled and sculptured-keeled forms, it would probably 

seem as if two species were present, but the intermediate form points to the fact that T. columbiana 

varies markedly in its spiral sculpture. 

Hickman (written commun., 1975) assigns Taranis 

columbiana to Ptychosyrinx. 

The specimen figured by Adegoke (1969, pl. 13, fig. 10) 

as Drillia columbiana Anderson and Martin, from the 

Temblor Formation (Oligocene and Miocene), Coalinga 

region, California, is much larger and different in 

outline than Taranis columbiana. It lacks the deep 

concavity below the whorl sutures ofT. columbiana. 

Localities.-USGS 15264, 15264a, b, 15310, 15310d, 

M3871, M3872, cf. 15278. 

Subfamily CLAVINAE 

Genus Spirotropis Sars 

Spirotropis Sars, 1878, Mollusca regionis Arcticae Norvegicae, p. 242, 

pl. 17, figs. 5a, 5b. 

Type species.-By monotypy, Spirotropis carinata 

Philippi. Holocene, Norway to Azores. 

Spirotropis is thin shelled and has a moderately high 

spire and has roundly keeled whorls. The sinus, which is 

rather deep and U -shaped, is confined to the shoulder 

above the keel. Powell (1966, p. 74) says that the typical 

adult has medially carinate whorls but is otherwise 

smooth except for some weak, oblique, peripheral nodes 

on the early postnuclear whorls. 

The known fossil occurrences of Spirotropis are in the 

Miocene to Pleistocene of Europe and the Oligocene to 

Pleistocene of northwestern America (Powell, 1966, 

p. 75). 

Spirotropis kincaidi (Weaver) 

Plate 7, figures 1, 9, 10, 13 

Turris kincaidi Weaver, 1916a, Washington Univ. (Seattle) Pubs. 

Geology, v. 1, p. 53, pl. 5, fig. 67. 

Turricula kincaidi (Weaver). Tegland, 1933, California Univ. Pubs. 

Dept. Geology, v. 23, p. 126-127, pl. 10, figs. 12, 13. 

Spirotropis kincaidi (Weaver). Grant and Gale, 1931, San Diego Soc. 

Nat. Hist. Mem., v. 1, p. 548. Weaver, 1942, Washington Univ. 

(Seattle) Pubs. Geology, v. 5, p. 522, pl. 97, figs. 18, 19, 25. 

Spirotropis kincaidi is small to moderate in size and 

bears a sharply rounded keel or shoulder just above the 

suture. The whorls of the spire are smooth above the 

keel except for the U-shaped sinus and three flat-topped 

spiral cords below the keel. The body whorl is sculptured 

with similar flat spiral cords below the keel which are 

closely spaced. No nodes are discernible on any of the 

specimens examined, nor are they present on the 

holotype. The protoconch consists of two smooth whorls 

with the apex slightly arcuate and recurved. 

Holotype.-CAS 470. 

Type locality.-UW 256. In Union Pacific Railway cut 

1 mile north of Galvin Station, Lewis County, Wash. 

Lincoln Creek Formation (late Eocene to early 

Miocene). 

Hickman (written commun., 1975) assigns Spirotropis kincaidi to the genus Parasyrinx. 

Spirotropis kincaidi has a shorter, wider spire and a 

more sharply rounded keel than S. washingtonensis 

Etherington (1931, p. 113, pl. 14, figs. 8, 22, 34). 

Localities.-USGS 15264, 15310, 15310d, 15588, 

M3856, M3857, M3871, M3872, M3878. 

Occurrence elsewhere.-Lincoln Creek Formation 

(late Eocene to early Miocene) and Blakeley(?) Formation (late Oligocene and early Miocene), Washington; 

Tunnel Point Sandstone (middle Oligocene), Oregon. 

Genus Suavodrillia Dall 

Suauodrillia Dall, 1918, U.S. Natl. Mus. Proc., v. 54, no. 2238, p. 331. 

Type species.-By original designation, Drillia 

kennicotti Dall, Holocene, Alaska. Bering Strait south 

to the Aleutian Islands. 

The known fossil occurrences of S uavodrillia are in 

the Miocene and Pliocene of Japan and the Oligocene of 

Washington and Oregon. 

Some of the diagnostic features of Suavodrillia, as 

given by Powell (1966, p. 82), are 

Shell moderately large, up to 37 mm, rather thin, claviform, with a 

tall pagodiform spire and a narrow body-whorl, quickly contracted to a 

moderately long, decidedly twisted, and rather deeply notched anterior canal. Protoconch small, turbinate of2 1

/z smooth whorls, the tip 

almost central and slightly inrolled. Spire-whorls dominated by a 

strong but narrowly rounded keel, which is situated at about a third 

whorl height. Body-whorl and a second keel, emergent at the lower 

suture, and seven more below to the anterior end, but becoming 

progressively weaker. There is also a broad but weak subsutural fold 

which bears two closely spaced fine threads at its lower margin. The 

shoulder slope is wide, flat and steep, which with the carina, impart 

the pagodalike profile to the spire. Aperture ovate-pyriform. Outer lip 

thin edged, with a moderately deep U-shaped sinus, at the apex of a 

wide, chevron-shaped entrance; the apex is on the lower part of the 

shoulder slope, immediately above the carina. The inner lip is a 

slightly excavated smooth callus with processes. 
40 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

Power cites Suavodrillia hertleini Durham (1944, p. 

182-183, pl. 14, fig. 1) from the Oligocene ofWashington 

as a characteristic species. 

Suavodrillia winlockensis (Effinger) 

Plate 7, figures 4, 11, 12, 15, 33-36, 38 

Surcula dickersoni (Weaver). Dickerson, 1917, California Acad. Sci. 

Proc., ser. 4, v. 7, p. 161, pl. 31, figs. 3a, 3b. 

Spirotropis (Spirotropis) winlockensis Effinger, 1938, Jour. Paleontology,v. 12,p. 386,pl.46,figs. 12, 16. Weaver, 1942, Washington 

Univ. (Seattle) Pubs. Geology, v. 5, p. 520--521, pl. 97, figs. 5, 8, 9. 

Suavodrillia winlockensis is a small thin-shelled 

species with a high, slim, turreted spire. The aperture is 

ovate, and the siphonal canal is moderately long, recurved, and notched. The primary sculpture consists of 

one strong narrow keel at the shoulder, a strong concavity just below the shoulder, and two strong rounded 

spirals on this concavity. The posterior spiral is one half 

as wide as the anterior one. The surface above the 

shoulder has fine slightly rounded spirals of unequal 

width that are closely spaced. Below the shoulder on the 

body whorl are three slightly rounded strong spirals 

alternating with weaker spirals of half the width. The 

remainder of the shell to the tip of the canal bears 

flat-topped spiral cords of lesser strength; these cords 

alternate with incised lines. The sinus occupies most of 

the shoulder and is shaped like a rounded, very open V. 

The early whorls of some immature shells show a second 

strong spiral just above the suture, and instead of being 

concave are straight sided. Well-preserved juvenile 

specimens may bear a fine reticulate sculpture on the 

shoulder; the sculpture is formed by fine spiral threads 

crossing the lines of the suture. The size and arrangement of secondary spiral cords varies consid~rably 

on different specimens. On a few specimens the keel is 

grooved. The protoconch is small and smooth with the 

tip almost central. 

Holotype.-VCMP 33607. 

Type locality.-VW 239. South bank of the Cowlitz 

River at old Gries Ranch, Lower Cowlitz Valley, Wash. 

Gries Ranch Formation (early Oligocene). 

Suavodrillia dickersoni (Weaver) (1916a, p. 54, pl. 5, 

fig. 66), from the Lincoln Creek Formation (late Eocene 

to early Miocene), Washington, is not so strongly keeled 

and seems to have a much shorter siphonal ca~al. 

Localities.-VSGS 15264, 15264b, e, 15310, 15310a, 

c, e, f, h,j, 15499, 15530, 18638, 21612, M3871, M3878. 

Occurrence elsewhere.-Gries Ranch Formation 

(early Oligocene), Washington. 

Family PYRAMIDELLIDAE 

Genus Odostomia Fleming 

Odostomia Fleming, 1813, Brewster's Edinburgh Encyclopedia, v. 7, 

pt. 1, p. 76. 

Type species.-By subsequent designation (Gray, 

1847, Zool. Soc. London Proc., pt. 15, p. 159), Turbo 

plicatus Montagu. Holocene, Europe. 

Odostomia winlockiana Effinger 

Plate 3, figures 7, 9, 10 

Odostomia (Odostomia) winlockiana Effinger, 1938, Jour. Paleontology, v. 12, p. 375, pl. 46, figs. 13, 17, 20. Weaver, 1942, 

Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 306--307, pl. 64, 

figs. 23, 24, 30. 

Shell very small (2.5-4.5 mm high and 1.0-2.2 mm 

wide), adult specimens probably have five whorls. The 

surface is white and polished, and the protoconch 

heterostrophic. A single fold can be seen on the columella. The sutures are linear and impressed. The body 

whorl is moderately large, and the aperture probably 

subovate. 

Holotype.-VCMP 33564. 

Type locality.-ln south bank of Cowlitz River at old 

Gries Ranch, NV! sec. 25, T. 11 N., R. 2 W., Cowlitz 

County, Wash. Gries Ranch Formation, early 

Oligocene. 

The species is distinguished by the moderately 

rounded whorls and impressed sutures. Odostomia may 

be parasitic upon the mollusks Ostrea, Pecten, and Crepidula and on polychaete worms (Keen, 1971, p. 770). 

Localities.-VSGS 5329, 15310. 

Occurrence elsewhere.-Gries Ranch Formation 

(early Oligocene), Washington. 

Family ACTEONIDAE 

Genus_ ~_Qte~n -~_ontfort 

Acteon Montfort, 1810, Conchyliologie systematique, v. 2, p. 315. 

Type species .-By original designation, Vol uta 

tornatilis Gmelin = Voluta tornatilis Linne. Holocene 

seas of Europe. 

Acteon chehalisensis (Weaver) 

Plate 7, figures 20, 21 

Acteocina chehalisensis Weaver, 1916a, Washington Univ. (Seattle) 

Pubs. Geology, v. 1, p. 55, pl. 4, figs. 55, 56. 

Acteon chehalisensis (Weaver). Weaver, 1942, Washington Univ. 

(Seattle) Pubs. Geology, v. 5, p. 543, pl. 99, figs. 38--40. 

Three incomplete specimens are in the collections 

examined. The body whorl is large and somewhat 

elongate, and the spire is moderately high and consists 

of four whorls. The body whorl of the middle-sized 

specimen bears about 30 spiral ribs. The body whorl of 

the largest specimen has twice as many ribs; they each 

seem to have split in two. The smallest specimen does 

not have the outer shell layer preserved. Fine axial 

threads occur in the spaces between spiral ribs. The 

spirals are offset at irregular intervals on the largest 

specimen. 

Holotype.-CAS 474. 

Type locality .-UW 352. In Union Pacific Railway cut 

1 mile north of Galvin Station, Lewis County, Wash. 

Lincoln Creek Formation (late Eocene to early 

Miocene). 

Acteon parvuum Dickerson (1917, p. 172, pl. 29, figs. 

12a, 12b) from the Gries Ranch Formation (early 
CLASS SCAPHOPODA 41 

Oligocene), Washington, has a more inflated body 

whorl, lower spire, and only about 20 spiral ribs. Although A. parvuum has been recorded from the 

Pittsburg Bluff Formation (Warren and others, 1945), it 

is not present in the collections studied. 

Localities.-VSGS 15264, 15537, 15588, M3871. 

Occurrence elsewhere .-Lincoln Creek Formation 

(late Eocene to early Miocene), Washington. 

Acteon? n. sp.? 

Plate 7, figure 19 

A small (4 mm high, incomplete; 2.7 mm wide) incomplete, poorly preserved specimen ofActeon? is in the 

collections. It is unique in that the shell is not completely sculptured by spiral ribs or incised lines. The 

smallest whorl on the shell has widely spaced spiral 

lines. The next largest whorl is smooth except for one 

incised line seen where the next whorl has broken away 

at the suture. The upper third of the body whorl is 

smooth; the lower two-thirds is sculptured with incised 

lines except at the base where the sculpture is of flattopped spiral ribs. The aperture is almost completely 

missing, but the inner lip seems to be thickened, and the 

general outline of the aperture is similar to that of 

Acteon. As all the fossil species of Acteon seen have had 

all the whorls spirally sculptured, it seems improbable 

that this specimen is simply an immature form of Acteon chehalisensis (Weaver) or of some other described 

fossil species. 

Locality .-USGS 15588. 

Family SCAPHANDRIDAE 

Genus Scaphander Montfort 

Scaphander Montfort, 1810, Conchyliologie systematique, v. 2, p. 335. 

Type species.-By original designation, Bulla lignaria Linne. Holocene, eastern North Atlantic to 

Mediterranean Sea. 

Scaphander stewarti Durham 

Plate 7, figures 18, 23--32 

Scaphander stewarti Durham, 1944, California Univ. Pubs., Dept. 

Geol. Sci. Bull., v. 27, p. 189, pl. 14, fig. 15. Hickman, 1969, Oregon 

Univ. Mus. Nat. Hist. Bull. 16, p. 100-101, pl. 14, figs. 1-3. 

Scaphander stewarti is of moderate size, thin shelled, 

and subovate in outline. The spire is sunken and covered with callus that continues as a ridge on the posterior edge of the aperture to the outer lip edge. The 

outer lip leaves the spire at an angle and flares out 

beyond the body whorl. The shell is so thin that the 

outer lip is usually broken off; it is not completely 

preserved on any of the specimens in the collections 

examined. The shell is sculptured with flat spiral ribs 

that are grooved medially on the posterior portion of the 

shell and are split into two ribs on the anterior portion. 

The ribs are of unequal width and are serrated along the 

edges. 

Holotype.-VCMP 35483. 

Type locality.-In seacliffSW14NE14 sec. 19, T. 29 N., 

R. 1 E., Nordland quadrangle, Jefferson County, 

Wash.Quimper Sandstone of Durham (1942) (early and 

middle Oligocene). 

Scaphander stewarti differs from Scaphander 

washingtonensis Weaver (1916a, p. 56, pl. 5, fig. 68) by 

having the lip more roundly truncated at the anterior 

end. The aperture is more inflated anteriorly, and the 

outer lip leaves the spire at an upward angle. 

Localities.-VSGS 2714, 5407, 15264, 15264b, e, 

15310, 15310a, b, d, j, 15312, 15537, 15545, 15583, 

15586, 15588, 18638, 21612, M3858, M3868, M3871, 

M3872, M3878. 

Occurrence elsewhere .-Quimper Sandstone of 

Durham (1942) (early and middle Oligocene), 

Washington; Gries Ranch Formation (early Oligocene), 

Keasey Formation (late Eocene and early Oligocene), 

and Eugene Formation (early and middle Oligocene), 

Oregon. 

Class SCAPHOPODA 

Family DENTALIIDAE 

Genus Dentalium Linne 

Dentalium Linn~, 1758, Systema naturae, ed. 10, p. 785. 

Type species.-By subsequent designation (Montfort, 

1810), Dentalium elephantinum Linne. Holocene, 

Amboynaland, Philippine Islands. 

Subgenus Fissidentalium Fischer 

Type species.-By monotypy (Fischer, 1885, Manuel 

de Conchyliologie, p. 894), Dentalium ergasticum 

Fischer. Living in Gulf of Gascony and the Atlantic 

Ocean ranging in water depth from 400 to 1,900 m. 

Dentalium (Fissidentalium?) laneensis Hickman 

Plate 7, figures 14, 17 

Dentalium (Fissidentalium?) laneensis Hickman, 1969, Oregon Univ. 

Mus. Nat. Hist. Bull. 16, p. 74, pl. 9, figs. 1-6. 

About 30 specimens of Dentalium are in the Pittsburg 

Bluff collections; of these about 10 have some of the 

original shell preserved, although none of them are 

complete specimens. The longitudinal ribs are narrow, 

strong, and rounded near the apex. Secondary ribs may 

appear between 8 and 10 mm from the apex where the 

primary ribs become less pronounced. The primary ribs 

become broader and flatter nearer the middle of the 

shell, and may be completely absent near the aperture 

so that the shell is smooth. Wear. and exfoliation make 

specific identification of most of the specimens impossible, but I think that all the specimens represent one 

species. The shell is moderately curved near the apex; 

the remainder of it is straight or nearly so. 

Holotype .-VO 27332. 

Type locality .-VO 2538. In roadcut, 30th Ave. and 

Agate St., Eugene, Oreg. NW14 sec. 8, T. 18 S., R. 3 W. 

Eugene quadrangle, Eugene Formation (early and 

middle Oligocene). 
42 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

The longitudinal sculpture distinguishes Dentalium 

laneensis from other described species of the west coast 

Tertiary. 

Localities.-USGS 2723, 15264, 15278, 15310, 

15310g, 15530, 15588,~3856,~3858,~3871,~3872. 

Occurrence elsewhere.-Eugene Formation (early 

and middle Oligocene), Oregon; Wygal Sandstone 

~ember of the Temblor Formation (late Oligocene), 

California. 

Class PELECYPODA 

Family NUCULIDAE 

Genus Nucula Lamarck 

Nucula Lamarck. 1799, Soc. Hist. Nat. Paris Mem., ser. 1, p. 87. 

Type species.-By monotypy, Area nuculeus Linn~. 

Holocene, France. 

Subgenus Leionucula Quenstedt 

Leionucula Quenstedt, 1930, Geol. und PaUiont. Abhand., Bd. 22, Heft 

1, p. 112. 

Type species.-By original designation, Nucula albensis d' Orbigny. Cretaceous, England and France. 

Nucula (Leionucula) vokesi, n. sp. 

Plate 8, figures 10, 13, 16, 17 

Nucula vokesi is a small species (5.2 to 7.3 mm long 

and 3.7 to 6.3 mm high) with a smooth shell sculptured 

only with concentric grooves. The shell is longer than 

high and moderately inflated, and it has a well-defined, 

elongate, heart-shaped escutcheon. The shell is produced along the posterior margin and bears a faint sulcus parallel to the anterior dorsal margin; the sulcus is 

about 1 mm from the margin. The poorly preserved 

hinge of one right valve (pl. 8, fig. 17) shows 8 or 9 teeth 

preserved in the posterior series (the teeth stop at the 

edge of the resilifer); and 9 teeth or more preserved in 

the anterior series (the teeth continue above the resilifer to the beak). A left valve, also poorly preserved, 

shows 5 or 6 teeth in the anterior series and perhaps 

about 15 teeth in the posterior series that continue 

above the resilifer to the beak (pl. 8, fig. 16). The inner 

ventral margin has not been exposed. 

Holotype.-Herewith designated USN~ 214074 (pl. 

8, fig. 10). 

Type locality.-USGS 18638. Type area of the 

Pittsburg Bluff Formation (middle Oligocene), Oregon. 

The holotype is a small right valve 6.5 mm long and 

4. 7 mm high; the hinge is not exposed. 

The resilifer is longer, and the shell is less inflated 

and lacks the bunched concentric threads that 

characterize Nucula (Leionucula) nuculana (Dall) 

(Dall, 1909, p. 125-126, pl. 18, fig. 2; ~oore, 1963, p. 

52-53, pl. 11, figs. 2, 5, 10; pl. 12, fig. 1). Nucula hanniballi Clark (1925, p. 73-7 4, pl. 8, fig. 2), a species that 

occurs in the Blakeley Formation ofWeaver (1912) (late 

Oligocene and early ~iocene), has radial sculpture. N. 

(Leionucula) vokesi is rare in the Pittsburg Bluff 

Formation. 

Localities.-USGS 2714, 15264, 15310, 15536, 15586, 

15588, 18638. 

Genus Acila Adams and Adams 

Acila Adams and Adams, 1858, Genera of Recent Mollusca, v. 2, p. 

545. 

Type species.-By subsequent designation (Stoliczka, 

1871, India Geol. Survey ~em. Palaeontologia Indica, 

v. 3, p. 325),Nucula divaricata Hinds. Holocene, Korea. 

Subgenus Truncacila Schenck 

Truncacila Schenck, 1931, in Grant and Gale, San Diego Soc. Nat. 

Hist. Mem., v. 1, p. 115. 

Type species.-By original designation, Nucula 

castrensis Hinds, Holocene, Sitka, Alaska, to San Diego, 

Calif. 

Truncacila originated in the Cretaceous. It prefers a 

cool temperate habitat and depths of 5-500 fathoms 

(10-914 m) (Schenck, 1936, p. 33-35). Truncacila had its 

greatest development in the Oligocene (Schenck, 1936, 

p. 38). It is one of the most common fossils in the 

Pittsburg Bluff Formation. 

Slodkewitsch (1967, p. 64) proposed Lacia, a new 

subgenus of Acila, with Nucula (Acila) shumardi Dall 

as the type species. No diagnostic features were given 

that validly separate the subgenus Lacia from Truncacila and the subgenus Truncacila is here retained. 

Acila (Truncacila) shumardi (Dall) 

Plate 8, figures 1-9, 11, 12, 14, 15, 18 

Nucula (Acila) decisa Conrad. Dall, 1898, Wagner Free Inst. Sci. 

Trans., v. 3, pt. 4, p. 573. Dall, 1900, Wagner Free Inst. Sci. Trans., v. 

3, pt. 5, pl. 40, figs. 1, 3. NotNucula decisa Conrad in Blake, 1855, 

Pacific R.R. Survey, v. 5, p. 322, pl. 3, fig. 19. 

Nucula (Acila)shumardi Dall, 1909, U.E. Geol. Survey Prof. Paper 59, 

p. 103. Clark, 1925, California Univ. Pubs., Dept. Geol. Sci. Bull., v. 

15, no. 4, p. 75, pl. 8, fig. 11. Tegland, 1933, California Univ. Pubs., 

Dept. Geol. Sci. Bull., v. 23, no. 3, p. 107, pl. 5, fig. 10. 

Acila shumardi Dall. Weaver, 1916a, Washington Univ. (Seattle) 

Pubs. Geology, v. 1, no.1, pl. 3, fig. 43. Clark, 1918, California Univ. 

Dept. Geology Bull., v. 11, no. 2, p. 95, 121-122, pl. 13, figs. 7, 8, 17. 

Schenck and Keen, 1940, California fossils, pl. 28, fig. 2. 

Acila (Truncacila) shumardi (Dall). Schenck, 1936, Geol. Soc. 

America Spec. Paper 4, p. 64-67, pl. 4, figs. 5-7, 9; pl. 6, figs. 1-11, 

text fig. 7 (18). Weaver, 1942, Washington Univ. (Seattle) Pubs. 

Geology, v. 5, p. 25-26, pl. 7, figs. 5-7, 11; pl. 8, figs. 2, 5 [1943]. 

Hickman, 1969, Oregon Univ. Mus. Nat. Hist. Bull. 16, p. 26--27, pl. 

1, figs. 6, 7, 10. 

Acila shumardi is large to moderate in size (largest 

specimen: 30 mm long, 22 mm high, and 16 mm thick), 

and is sculptured with many narrow ribs separated by 

small spaces which on some specimens are barely 

discernible and could be described as incised lines. 

Secondary bifurcation of the ribs may be present at the 

ventral margin either in the mid portion of the anterior 

halfofthe shell or along the anterior side ofthe primary 

bifurcation. On one specimen (USGS 18681) the ribs 
CLASS PELECYPODA 43 

split near the dorsal margin on the anterior portions of 

both valves of an articulated specimen. Although areas 

of secondary bifurcation, if present, usually occur on the 

largest specimens, such bifurcation has also been seen 

on specimens of only small to moderate size. The beaks 

are located at the sharply truncated posterior margin. 

The hinges exposed on two left valves (pl. 8, figs. 4, 8) 

show 7-10 posterior teeth and 16--22 anterior teeth. The 

hinges exposed on six right valves (pl. 8, figs. 6, 9, 11, 12, 

15, 18) show 7-11 posterior teeth and 17-20 anterior 

teeth. One specimen (pl. 8, fig. 18), at the anterior end of 

the posterior series of teeth, shows a deep irregular 

socket with an irregular toothlike projection at the 

ventral anterior edge. The number of teeth varies with 

the size of the individual shell, and the larger specimens 

have more teeth than the smaller ones. 

Holotype.-USNM 406405 (pl. 8, figs. 5, 6), figured by 

Dall (1900, pl. 40, figs. 1, 3). This specimen was 

erroneously cited as USNM 406505 by Weaver (1942, p. 

26) and Schenck (1936, p. 64). 

Paratypes.-USNM 107402, four specimens. 

Type locality.-USGS 2714, sec. 23, T. 5 N., R. 4 W., 

Vernonia quadrangle, Pittsburg, Columbia County, 

Oreg. Pittsburg Bluff Formation, middle Oligocene. 

The holotype is a right valve with the hinge exposed; 

the paratypes are articulated double valves and one 

specimen is an internal mold. A topotype from Dall's 

original collection is figured on plate 8, figures 2, 3, 7. 

The sculpture of closely spaced ribs with narrow 

interstices, the size of average specimens, and the 

posterior truncation distinguish A. shumardi from 

other species of Acila (Truncacila). 

The Acila zones of Schenck (1936, p. 41-44), like 

many biozones defined by single species, are not so 

restricted in time as some scientists supposed. Acila 

(Truncacila) nehalemensis (G. D. Hanna) has been 

collected from the Eugene Formation (early and middle 

Oligocene) by Hickman (1969, p. 24--25), whereas it was 

considered a guide fossil to beds of Keasey age (late 

Eocene and early Oligocene) by Schenck (1936, p. 42--44, 

60-63). Acila (Acila) gettysburgensis (Reagan) occurs in 

beds of Blakeley age (late Oligocene and early Miocene) 

as well as in the Astoria Formation (Miocene), as noted 

by Howe (1922, p. 58), Schenck (1936, p. 80), and Moore 

(1963, p. 54). Acila shumardi is found in the Gries 

Ranch Formation of early Oligocene age, and in the 

Oligocene portion of the Poul Creek Formation of 

middle Oligocene to early Miocene age in Alaska. Acila 

shumardi therefore ranges from early through middle 

Oligocene. The genus Acila is very useful for dating 

because of its abundance, good preservation, distinguishing characters, and ease of collection. If its 

presence is used with descretion along with the presence 

of other species in a fauna, it is a valuable tool. 

Localities.-USGS 2415, 2707, 2714, 2715, 2721, 

5394,15264, 15264a,b,e, 15310, 15310a-c,e-h,15311, 

15312, 15530, 15586, 15588, 18638, 18779, M3856, 

M3857, M3860, M3871, M3872, M3877, M3878. 

Occurrence elsewhere .-Poul Creek Formation (middle Oligocene to early Miocene), Yakataga and Katalla 

Districts, Gulf of Alaska, and Stepovak Formation of 

Burk (1965) (early and middle Oligocene), Alaska 

Peninsula; Lincoln Creek Formation (late Eocene to 

early Miocene), Washington; Gries Ranch Formation 

(early Oligocene), USGS 5210, 15298, 15585, Eugene 

Formation (early and middle Oligocene), upper part 

only, Alsea Formation (early, middle, and late 

Oligocene), Tunnel Point Sandstone (middle 

Oligocene), Oregon; Tumey (early and middle 

Oligocene), Alegria (middle Oligocene), Kirker (middle 

Oligocene), and upper San Emigdio (late Eocene to 

middle Oligocene), Formations, California. 

Family NUCULANIDAE 

Genus Litorhadia Stewart 

Litorhadia Stewart, 1930, Acad. Nat. Sci. Philadelphia Spec. Pub. 3, p. 

52-53. 

Type species .-By original designation, Leda acala 

Dall (1898, Wagner Free Inst. Sci. Trans., pt. 4, p. 586, 

pl. 32, fig. 3). Eocene, Wood's Bluff, Ala. 

Litorhadia washingtonensis (Weaver) 

Plate 9, figures 1-10, 12 

Leda washingtonensis Weaver, 1916a, Washington Univ. (Seattle) 

Pubs. Geology, v. 1, p. 34-35, pl. 3, figs. 25, 26. 

Nuculana washingtonensis (Weaver). Weaver, 1942, Washington 

Univ. (Seattle) Pubs. Geology, v. 5, p. 38-39, pl. 8, figs. 18, 20, 26. 

Hickman, 1969, Oregon Univ. Mus. Nat. Hist. Bull. 16, p. 27, 30, pl. 

1, figs. 8, 11. 

Leda lincolnensis Weaver, 1916a, Washington Univ. (Seattle) Pubs. 

Geology, v. 1, p. 35, pl. 3, figs. 23, 24. 

Litorhadia washingtonensis in the collections 

examined attains a maximum length of 29 mm, 

although it is usually a small form. It is sculptured with 

concentric ridges. The· posterior dorsal margin is 

markedly concave, and the shell is produced, turning 

outward, along the margin of the escutcheon. The 

posterior end is truncated and pointed, and the anterior 

margin is evenly rounded. The beaks are slightly 

anterior to the midpoint of the shell. The right valve has 

20 posterior and 26 anterior teeth; the left valve has 24 

anterior and 18 posterior teeth, as counted on the two 

available exposed hinges. The chondrophore is long, 

shallow, moderately impressed, and symmetrical. 

Lectotype.-CAS 451 is herewith selected as the 

lectotype. It is one of the two specimens cited by Weaver 

(1942, p. 39) as syntypes. 

Type locality.-ln Union Pacific Railway cut, 1.4 mile 

northwest of Galvin Station, in sec. 27, T. 15 N., R. 3 W., 
44 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

Malone quadrangle, Washington. Lincoln Creek Formation (late Eocene to early Miocene). 

The lectotype (Weaver, 1942, pl. 8, figs. 18, 20) is a left 

valve with the hinge exposed and the exterior of the 

shell showing the concentric ridges. The shell is worn at 

the posterior extremity and seems to be square, whereas 

it was originally pointed. 

Closely related forms are found in the Foul Creek 

(middle Oligocene to early Miocene) Formation, 

Yakataga District, Gulf of Alaska, and possibly in the 

upper Kreyenhagen Shale or Tumey Formation, 

California. 

Localities.-USGS 2714, 5394, 15264, 15264a-c, e, 

15278,15310,15310a,g,j,15312, 15519,15530,15532, 

15537, 15545, 15548, 15583, 15586, 15588, 18638, cf. 

M3857, M3867, M3868, cf. M3869, M3871, M3872, 

M3878. 

Occurrence elsewhere .-Gries Ranch Formation 

(early Oligocene), Lincoln Creek Formation (late 

Eocene to early Miocene), Quimper Sandstone of 

Durham (1942) (early and middle Oligocene), and 

Blakeley Formation of Weaver (1912) (late Oligocene 

and early Miocene), Washington; Eugene Formation 

(early and middle Oligocene), Alsea Formation (early to 

late Oligocene), and Tunnel Point Sandstone (middle 

Oligocene); upper part ofBrabb's (1960) Rices Mudstone 

Member of the San Lorenzo Formation (early Oligocene 

to early Miocene), California. 

Genus Yoldia Moller 

Yoldia Moller, 1842, Index molluscorum Groenlandiae, p. 18. 

Type species .-By subsequent designation (Verrill 

and Bush, 1898, U.S. Natl. Mus. Proc., v. 20, no. 1139, p. 

858), Yoldia arctica (Gray) = Y .hyperborea (Gould). 

Holocene, northern seas of Europe. 

Subgenus Kalayoldia Grant and Gale 

Kalayoldia Grant and Gale, 1931, San Diego Soc. Nat. Hist. Mem., v. 

1, p. 128. 

Type species .-By original designation, Y oldia 

cooperii Gabb. Miocene to Holocene, Pacific coast of the 

United States. Living from central California to 

northern Lower California, Mexico (Hertlein and 

Grant, 1972, p. 51). 

Yoldia (Kalayoldia) oregona (Shumard) 

Plate 9, figures 14, 16-18 

Leda oregona Shumard, 1858, Acad. Sci. St. Louis Trans., v. 1, p. 

121-122 (Reprinted in Dall, 1909, U.S. Geol. Survey Prof. Paper 59, 

p. 187). Gabb, 1869, California Geol.Survey, Paleontology, v. 2, p. 

121. 

Nuculana oregona (Shumard). Meek, 1864, Smithsonian Misc. Colin. 

183, p. 5, 27. Conrad, 1866, Smithsonian Misc. Colin. 200, p. 3. 

Neilo oregona (Shumard). Conrad, 1865, Am. Jour. Conchology, v. 1, p. 

153. 

Yoldia (Cnestrium)oregona (Shumard). Dall, 1909, U.S. Geol. Survey 

Prof. Paper 59, p. 105, pl.19, fig. 4. Not Yoldia (Cnestrium)oregona 

(Shumard) of Dall, 1922, Am. Jour. Sci., ser. 5, v. 4, p. 310, nor 

Yoldia oregona (Shumard) of Etherington, 1931, California Univ. 

Pubs., Dept. Geol. Sci. Bull., v. 20, p. 67, pl. 1, fig. 8. 

Yoldia (Portlandia) oregona (Shumard). Weaver, 1942, (in part), 

Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 49, pl. 9, fig. 16; 

not pl. 9, fig. 8. 

Yoldia (Kalayoldia) oregona (Shumard). Grant and Gale, 1931, San 

Diego Soc. Nat. Hist. Mem., v. 1, p. 130. Trumbull, 1958, Jour. 

Paleontology, v. 32, no. 5, p. 900-901, pl. 115, figs. 2, 3. Moore, 1963, 

U.S. Geol. Survey Prof. Paper 419, p. 58, pl. 12, fig. 20. Hickman, 

1969, Oregon Mus. Nat. Hist. Bull. 16, p. 31-32, pl. 1, figs. 14, 15. 

?Yoldia tenuissima Clark, 1918, California Univ. Pubs. Dept. Geol. 

Sci. Bull., v. 11, p. 125-126, pl. 11, fig. 10; pl. 12, figs. 8, 14. 

Y oldia oregona is moderate to large in size and is 

sculptured with concentric lines. The umbos are located 

medially or slightly anterior to the midline. The 

anterior end is evenly rounded, and the posterior end is 

recurved and sharply attenuated. The lectotype has 

about 20 teeth on the concave hinge line and about 25 

teeth on the convex hinge line. 

Lectotype.-USNM 562470 (designated by Trumbull, 

1958, p. 900). 

Type locality.-A few miles south of Oregon City, 

Oreg. (Oligocene). 

Yoldia tenuissima Clark (1918, p. 125--126, pl. 11, fig. 

10; pl. 12, figs. 8, 14) is perhaps conspecific with Y. 

oregona. The poorly preserved holotype ofY. tenuissima 

seems to have a sloping anterior dorsal margin, rather 

than the almost straight margin ofY. oregona, but this 

is not true of a specimen subsequently figured by 

Clark(1925, pl. 8, fig. 5) as Y. tenuissima. Clark (1918, p. 

126) differentiates the two species on the basis that Y. 

tenuissima has more posterior beaks, a somewhat more 

attenuate posterior end, and fewer teeth on the 

posterior margin. 

Localities.-USGS 2714, 2722, 15264, 15264e, 15310, 

15310b, f, 15312, 15499, 15516, 15586. 

Occurrence elsewhere.-Lincoln Creek Formation 

(late Eocene to early Miocene), Washington; Eugene 

Formation (early and middle Oligocene), Oregon. 

Family MYTILIDAE 

Genus Mytil us Linne 

Mytilus Linne, 1758, Systema naturae, ed. 10, p. 704. 

Type species.-By subsequent designation (Anton, 

1839, V erzeichniss der conchy lien welche sich in der 

Sammlung von H. E. Anton befinden, p. 17), Mytilus 

edulis Linne. Miocene to Holocene; living, cosmopolitan 

except in extreme tropical water (Hertlein and Grant, 

1972, p. 163). 

Mytilus' cf. M,. snohomishensis Weaver 

Two small, incomplete, and poorly preserved 

specimens of Mytilus are in the collections. Owing to 

the state of their preservation, they cannot be positively identified. They are compared to Mytilus 

snohomishensis Weaver (1912, p. 59, pl. 13, fig. 110), a 

species that is found in the middle and upper:Oligocene 
CLASS PELECYPODA 45 

of Oregon and Washington and possibly also in the 

lower Miocene. The two specimens have terminal beaks, 

and the dorsal margin has a pronounced angle, possibly 

at about one-fourth to one-third the distance from the 

beak. Only the internal shell layer is preserved; it is 

smooth except at the ventral margin, where weak 

longitudinal folds can be seen. 

Localities.-USGS 2714, 15586. 

Occurrence elsewhere.-Of Mytilus snohomishensis: 

Lincoln Creek Formation (late Eocene to early 

Miocene), Blakeley (late Oligocene and early Miocene) 

and Twin River Formations (late Eocene to late 

Oligocene), Washington; Eugene Formation (early and 

middle Oligocene), Oregon. 

Subfamily CRENELLINAE 

Genus Crenella Brown 

Crenella Brown, 1827, Illus. Conchology, Great Britain, v. 1, pl. 31, 

figs. 12-14; 1844, ed. 2, p. 75, pl. 23, figs. 12-14. 

Type species.-By monotypy, Mytilus decussatus 

Montagu. Holocene, northern Norway. 

Crenella porterensis Weaver 

Plate 12, figure 12 

Crenellaporterensis Weaver, 1912, Washington Geol. Survey Bull.15, 

pl. 14, fig. 116, Weaver, 1916a, Washington Univ. (Seattle) Pubs. 

Geology, v. 1, p. 36-37, pl. 3, figs. 41, 42. Tegland, 1933, California 

Univ. Pubs., Dept. Geol. Sci. Bull., v. 23, p. 112, pl. 6, fig. 2. 

This one specimen of Crenella porterensis is incompletely exposed in rock. The preserved inner shell layers 

show that some of the ribs bifurcate near the ventral 

margin. The margin of the valves is crenulate. The shell 

is moderately inflated, the inner shell layers are pearly, 

and faint concentric lines are visible on one small portion of the shell. 

Holotype.-CAS 454A. 

Type locality.-In railroad cut on Union Pacific 

Railway 1 mile north of Galvin Station, Lewis County, 

Wash., sec. 27, T. 15 N., R. 3 W., Centralia quadrangle. 

Lincoln Creek Formation (late Eocene to early 

Miocene). 

C. porterensis is distinguished from Crenella 

washingtonensis Weaver (1916a, p. 37, pl. 3, fig. 40) 

from the Lincoln Creek Formation by its larger size and 

its strong radial sculpture. 

Locality.-USGS 15583. 

Occurrence elsewhere.-Poul Creek Formation (middle Oligocene to early Miocene), Katalla District, Gulf 

of Alaska; Lincoln Creek Formation (late Eocene to 

early Miocene) and Blakeley Formation of Weaver 

(1912) (late Oligocene and early Miocene), Washington; 

Keasey Formation (late Eocene and early Oligocene), 

Alsea Formation (early to late Oligocene), and possibly 

in the Astoria Formation (Miocene), Oregon. 

Family CARDITIDAE 

Subfamily CARDITAMERINAE 

Genus Cyclocardia Conrad 

Cyclocardia Conrad, 1867, Am. Jour. Conchology, v. 3, p. 191. 

Type species.-By subsequent designation (Stoliczka, 

1871, India Geol. Survey Mem. Palaeontologia Indica, 

v. 3, XX, p. 281), Cardita borealis Conrad, Holocene, 

eastern United States, Labrador to Cape Hatteras. 

Cyclocardia (Cyclocardia) cf. C (C.) hannibali (Clark) 

Plate 9, figures 11, 13, 15 

Cyclocardia cf. C. hannibali is a rather small carditid, 

subcircular in outline. It has approximately 16 to 21 

rounded, slightly nodose ribs. The nodes seem to be 

formed by the bunching of the concentric threads that 

sculpture the entire shell. A rubber impression of the 

hinge of a left valve (pl. 9, fig. 15) shows the anterior 

cardinal tooth to be rather small, somewhat trigonal~ 

and blunt. The socket posterior to this tooth shows that 

the opposing cardinal tooth in the right valve was 

straight on the anterior edge. 

All the specimens of C. cf. C. hannibali are preserved 

as molds from one locality. The rubber impressions of 

these specimens show this species to be most closely 

related to C. hannibali (Clark) (1925, p. 88, pl. 19, figs. 6, 

7). If well preserved specimens were available, they 

would probably prove to be conspecific. 

Cyclocardia hannibali differs from C. hannai 

(Tegland), from the Blakeley Formation of Weaver 

(1912) (late Oligocene and early Miocene) of 

Washington, by having many more ribs; the ribs are a 

little thinner with wider interspaces but have similar 

sculpture. C. hannabali is distinguished from C. subtenta (Conrad), by narrower, higher, and more nodose 

ribs. The beaks seem to be higher and the anterior end 

more produced. C. hannibali occurs in the Astoria 

Formation (Miocene) of Washington and Oregon. 

Locality.-USGS 15537. 

Occurrence elsewhere.-Of C. hannibali: Ushikubitoga Formation (Oliogocene), Japan (Kanno, 1960); 

Poul Creek Formation (middle Oligocene to early 

Miocene), Alaska; Blakeley Formation (late Oligocene 

and early Miocene), Washington. 

Family LUCINIDAE 

Subfamily MYRTEINAE 

Genus Lucinoma Dall 

Lucinoma Dall, 1901, U.S. Natl. Mus. Proc., v. 23, p. 806. 

Type species.-By original designation, Lucina filosa 

Stimpson, Holocene, Grand Banks, off southeastern 

Canada, and northwestern United States, to Gulf of 

Mexico. 

Lucinoma columbiana (Clark and Arnold) 

Plate 10, figures 1-8 

Phacoides columbianum Clark and Arnold, 1923, California Univ. 

Pubs., Dept. Geol. Sci. Bull., v. 14, p. 144-145, pl. 25, figs. 2a, 2b. 
46 OLIGOCENE MARINE MOLLUSKS FROM THE PITISBURG BLUFF FORMATION IN OREGON 

Clark, 1925, California Univ. Pubs., Dept. Geol. Sci. Bull., v. 15, p. 

89, pl. 22, fig. 9. 

Lucina columbiana (Clark and Arnold). Weaver, 1942, Washington 

Univ. (Seattle) Pubs. Geology, v. 5, p. 145--146, pl. 34, figs. 13-15, 17. 

Lucinoma columbiana is small to moderate in size. 

Both valves of the largest figured specimen are 21.2 mm 

long, 20.0 mm high, and 11.6 mm thick, but one poorly 

preserved specimen was at least 32 mm long. L. columbiana is inflated, subquadrate in outline with the 

beaks rather high, and situated anterior to the middle of 

the shell. L. columbiana bears closely spaced, raised 

concentric lamellae, and on one specimen (pl. 10, figs. 3, 

7) the lamellae are more closely spaced toward the 

ventral margin. The anterior dorsal margin is concave, 

joining smoothly the rounded anterior end; the posterior 

dorsal margin is slightly convex, and it abruptly joins 

the somewhat truncated posterior end. The hinges illustrated (pl. 10, figs. 2, 6) are of a specimen that was 

articulated but the cardinal teeth were apparently 

destroyed when the valves were opened. The two valves 

are illustrated to show the muscle scars and the outline 

of the hinge. Of note are the large, heavy, seemingly flat 

areas posterior to the beaks on both valves, and the 

small node on both valves at the anterior end of the 

hinge. The ligament is mineralized at the dorsal edge of 

the posterior part of the hinges. The escutcheon is long 

and narrow. The lunule is moderate sized, impressed, 

and inequilateral, and the portion on the right valve is 

larger than that on the left. 

Holotype.-CAS 593. 

Type locality.-From sandstone and conglomerate of 

the Sooke Formation (early Miocene?) in the sea cliffs 

between the mouths of Muir and Kirby Creeks, west of 

Otter Point, Sooke Bay, Vancouver Island, B.C. 

The Holocene species Lucinoma annulata (Reeve) is 

less inflated than£. columbiana in proportion to its size, 

it does not have the heavy posterior hinge plate, and it 

has a smaller equilateral lunule. Lucinoma acutilineata 

(Conrad)(1849,p.725,pl.18,figs.2,2a,2b;Moore,1963, 

p. 7<J-71, pl. 15, figs. 7-10, 12), an early to middle 

Miocene species, is thinner than L. columbiana in 

proportion to its size; it has a much wider escutcheon, 

and it lacks the heavy flat posterior hinge plate. 

Lucinoma hannibali (Clark) (1925, p. 89, pl. 22, figs. 2, 

4) from Weaver's (1912) Blakeley Formation (late 

Oligocene and early Miocene) in Washington has a 

wider escutcheon and less concave dorsal margin than 

L. columbiana. 

Clark (1932) reportsLucinoma cf.L. columbiana from 

the Poul Creek Formation (middle Oligocene to early 

Miocene), Alaska. 

Localities.-VSGS 15264, 15588, M3858. 

Occurrence elsewhere.-Vshikubitoga Formation 

(Oligocene), Japan (Kanno, 1960); Sooke Formation 

(early Miocene?), Vancouver Island, B.C.; Blakeley 

Formation (late Oligocene and early Miocene), 

Washington. Possibly in the Eugene Formation (early 

and middle Oligocene), the Alsea Formation (ea:dy to 

late Oligocene), and the Tunnel Point Sandstone (middle Oligocene), Oregon. 

Family UNGULINIDAE 

Genus Felaniella Dall 

Felaniella Dall, 1899, Jour. Conchology, v. 9, no. 8, p. 244. 

Type species-By original designation, Mysia 

(Felania) usta Gould, Holocene, Japan. 

Felaniella can be distinguished externally from 

Diplodonta by its less prominent, centrally positioned 

beaks, its subquadrate outline, and its lesser inflation. 

Taras goodspeedi Durham and Diplodonta parilis 

(Conrad) probably belong in the genus Felaniella. 

Durham (1944, p. 145) pointed out the resemblance ofT. 

goodspeedi to the Holocene species T. sericata, which is 

now assigned to Felaniella (Keen, 1958, p. 103). 

Felaniella (Felaniella) snavelyi, n. sp. 

Plate 10, figures 9-11 

Felaniella snavelyi is subquadrangular, inequilateral, and thin-shelled; it bears the ligament in a marginal 

groove. The beaks are small and situated about onethird the distance from the anterior margin. The 

posterior dorsal margin slopes away from the beaks in a 

straight line at an angle of about 20°, and joins the 

rounded posterior margin abruptly; the anterior dorsal 

margin is shorter and a bit more rounded. One right 

valve has the hinge exposed (pl. 10, fig. 10) showing two 

cardinal teeth. The anterior tooth is moderately thick 

and subvertical; the posterior tooth is thick, bifid, and 

oblique. The pallial line seems to be doubled. 

Holotype.-Herewith designated as USNM 214099, 

plate 10, fig. 10. 

Type locality .-USGS 15264. On east side of Oregon 

State Highway 4 7, approximately 600 feet north of 

junction of Highway 4 7 and Scappoose-Vernonia Road 

(3,500 ft south of grid 2,660 and 5,000 ft west of grid 820, 

Army Engineers Vernonia quadrangle), Columbia 

County, Oreg. Pittsburg Bluff Formation (middle 

Oligocene). 

In external characters Felaniella snavelyi is identical 

to the living species F. serricata (Reeve). The shell of 

F. snavelyi is thicker, however, and the configuration of 

the nymph plate and ligament groove are different. The 

nymph plate of F. snavelyi is larger, heavier, and 

flanged along the dorsal margin, and it lacks the 

flattened, shallow trigonal pit that holds the resilium on 

F. serricata. The ligament groove and ligament are 

larger on F. snavelyi than on F. serricata. 

Felaniella goodspeedi Durham (1944, p. 145) is more 

rounded at the anterior and posterior margins, has a 

higher angle between the beak and the posterior and 
CLASS PELECYPODA 47 

anterior dorsal ~argins, and has more prominent beaks 

than F. snavelyi. Felaniella parilis (Conrad) (1848, p. 

432; Moore, 1963, p. 71, pl. 23, fig. 9) has a more rounded 

anterior and posterior margin and a higher angle 

between the beak and the posterior and anterior dorsal 

margins like Felaniella griesensis (Effinger) (1938, p. 

369). 

F. snavelyi is rare in the Pittsburg Bluff Formation. 

Most of the complete specimens preserved have the 

mineralized ligament intact. 

Localities.-USGS 2714, 15264, 15310, 15312, 15516, 

15537, 15544, 15586, M3858, M3871. 

Family CARDIIDAE 

Subfamily PROTOCARDIINAE 

Genus Nemocardium Meek 

Nemocardium Meek, 1876, U.S. Geol. Survey Territories, v. 9, p. 

167-168. 

Type species .-By subsequent designation (Sacco, 

1899, I. Moll. Liguria, pt. 27, p. 56), Cardium 

semiasperum Deshayes. Eocene, France. 

Subgenus Keenaea Babe 

Keenaea Habe, 1951, Genera of Japanese Shells: Pelecypoda, no. 2, p. 

152. 

Type species.-By original designation, Nemocardium samarangae Makiyama. Holocene, Japan. 

Nemocardium (Keenaea) lorenzanum (Arnold} 

Plate 10, figures 12-14 

Cardium cooperii Gabb var. lorenzanum Arnold, 1908, U.S. Natl. 

Mus. Proc., v. 34, p. 366, pl. 33, fig. 6; 1909, U.S. Geol. Survey Geol. 

Atlas, Santa Cruz Folio, p. 4, fig. 17. 

Cardium lorenzanum Arnold. Tegland, 1933, California Univ. Pubs., 

Dept. Geol. Sci. Bull., v. 23, p. 116-117, pl. 7, figs. 16, 17. 

Nemocardium lorenzanum (Arnold). Weaver, 1942, Washington 

Univ. (Seattle) Pubs. Geology, v. 5, p. 160, pl. 35, fig. 22, pl. 36, figs. 

3, 5. 

Nemocardium (Keenaea) lorenzanum (Arnold). Keen, 1954, Am. 

Paleontology Bull., v. 35, no. 153, p. 11. Hickman, 1969, Oregon 

Univ. Mus. Nat. Hist. Bull. 16, p. 38, pl. 2, fig. 7. 

Nemocardium lorenzanum is a small form in the 

Pittsburg Bluff Formation; the length of the largest 

specimen in the collections is 18. 3 mm, but most of the 

specimens are about 10 mmm long. N. lorenzanum is 

subquadrate in outline, is moderately inflated, and has 

prominent beaks. The hinge is not exposed. The shell is 

very thin. The well-developed posterior ridge demarcates the change in ribbing: the anterior portion bears 

flat small radial ribs separated by finely incised lines; 

the posterior portion bears narrow high ribs that are 

separated by interspaces almost as wide that bear a 

secondary concentric sculpture. This concentric 

sculpture is between the ribs and at right angles to 

them, and it consists of raised, thin, ridgelike intercalations that are evenly spaced but commonly not 

alined. 

Holotype.-USNM 165444. 

Type locality.-ln cliff in north bank of Chehalis 

River, at the town of Porter, Grays Harbor County, 

Wash. In sec. 22, T. 17 N., R. 4 W., Malone quadrangle. 

Lincoln Creek Formation (late Eocene to early 

Miocene). 

This species is distinguished by its \subquadrate 

outline and by its sculpture of more than 60 flat-topped 

ribs anterior to the posterior ridge and a few more than 

25 narrow high ribs posterior to the posterior ridge. 

Closely related forms occur in the Poul Creek Formation (middle Oligocene to early Miocene), Yakataga 

District, Gulf of Alaska, and in Burk's (1965) Stepovak 

Formation (early and middle Oligocene), McGinty Point 

section, Alaska. 

Localities.-USGS 15264, 15278, 15310, 15530, 

15537, 15548, 18638, M3873. 

Occurrence elsewhere .-Lincoln Creek Formation 

(late Eocene to early Miocene) and Weaver's (1912) 

Blakeley Formation (upper Oligocene and lower 

Miocene), Washington; Eugene Formation (lower and 

middle Oligocene), Alsea Formation (early, middle, and 

late Oligocene), Keasey Formation (late Eocene and 

early Oligocene), Oregon; upper part of Brabb's (1960) 

Rices Mudstone Member of San Lorenzo Formation 

(late Eocene to middle Oligocene), California. 

Family VENERIDAE 

Subfamily PITARINAE 

Genus Pitar Romer 

Pitar Romer, 1857, Krit. Unters. Art. Moll., Venus, p. 15. 

Type species.-By monotypy, Venus tumens Gmelin. 

Holocene, West Africa. 

Pitar (Pitar) dalli (Weaver) 

Plate 12, figures 1, 2, 4 

Pitaria dalli Weaver, 1916a, Washington Univ. (Seattle) Pubs. 

Geology, v. 1, p. 41, pl. 1, figs. 1-4. Tegland, 1929, California Univ. 

Pubs., Dept. Geol. Sci. Bull., v. 18, p. 278, pl. 21, figs. 4-9. 

Pitardalli (Weaver). Weaver, 1942, Washington Univ. (Seattle) Pubs. 

Geology, v. 5, p. 181-182, pl. 43, figs. 1-5, 8, 11. Hickman, 1969, 

Oregon Univ. Mus. Nat. Hist. Bull. 16, p. 46-47, pl. 3, figs.16-19, pl. 

5, figs. 2, 5. 

An internal mold of one almost complete large 

specimen is subovate in outline and moderately 

inflated. The few small internal molds are also subovate 

in outline but are less inflated. On one of these molds, 

the beaks are very close to the anterior margin; on all 

the others, they are about a third of the distance from 

the anterior end. One incomplete left hinge is figured 

(pl. 12, fig. 2). 

Syntypes.-CAS 460A, 460C, 460D. 

Type locality.-ln railroad cut on Union Pacific 

Railway 1 mile north of Galvin Station, Lewis County, 

Wash. Sec. 27, T. 15 N., R. 3 W., Centralia quadrangle. 

Lincoln Creek Formation (late Eocene to early 

Miocene). 
48 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

Localities.-USGS 15278, 15310, 15310a, 15499, 

15516, 15532, 15537, 15548, ~3873; c( 15519. 

Occurrence elsewhere .-Poul Creek Formation (middle Oligocene to early ~iocene), Yakataga and Katalla 

Dil;)tricts, Gulf of Alaska; Lincoln Creek Formation (late 

Eocene to early ~iocene) and the ~arrowstone Shale of 

Durham (1944), Washington; Eugene Formation (early 

and middle Oligocene), Alsea Formation (early to late 

Oligocene), Tunnel Point Sandstone (middle Oligocene), Oregon; Tumey Formation of Atwill (1935) (early 

and middle Oligocene), California. 

Genus Callista Poli 

Callista Poli, 1791, Testacea utriusque Siciliae, eorumque historia et 

anatomia, tome 1, p. 30. 

Type species.-By subsequent designation, Venus 

chione Linne (~eek, 1876). Holocene ~editerranean. 

Subgenus ',Macrocallista Meek 

Macrocallista Meek, 1876, U.S. Geol. Survey Territories, v. 9, p. 179. 

Type species.-By monotypy, Venus gigantea Gmelin 

= Venus nimbosa Lightfoot. Holocene, Caribbean. 

The mature specimens of Callista have much more 

massive hinge plates and all the teeth are larger than on 

specimens of Macrocallista of similar size; this is not 

true of juvenile specimens of Callista. Macrocallista is 

much more produced anteriorly, is less inflated, and has 

a thinner shell than Callista. The configuration and 

arrangement of teeth on both valves of Macrocallista so 

closely resembles that of Callista that it does not seem 

proper to separate Macrocallista except subgenerically. 

Placing Macrocallista as a subgenus ofCallista helps to 

show the close relation within this difficult and variable 

group. 

The hinge of Callista (Macrocallista) pittsburgensis 

differs from that of the type species of Macrocallista, 

Venus nimbosa Lightfoot. The hinge ofC. (M.) nimbosa 

is here described in order that the differences can be 

noted and the reasons for retaining C. (M.) 

pittsburgensis in Macrocallista understood. 

In the following description, the right valve is considered to have two anterior laterals, three cardinals, and a 

posterior lateral; the left valve is considered to have one 

anterior lateral and three cardinals. 

The right valve of Callista (Macrocallista) nimbosa 

has the two anterior laterals bordering a socket that 

receives the left anterior lateral. The right anterior 

laterals are smooth and rounded, the dorsal one is 

clearly defined with a slight pointed prominence at the 

anterior end. The ventral lateral is a thick, rather even 

swelling projecting a bit over the socket and perhaps, if 

strictly defined, is not a lateral tooth. The right anterior 

cardinal, the most prominent tooth, projects beyond all 

the others. It is thickest at the ventral end, and it thins 

and curves towards the anterior at the dorsal margin. 

The posterior edge of the tooth nearly parallels the 

anterior side of the middle cardinal. The right middle 

cardinals form a very deep socket between their nearly 

parallel surfaces. The right posterior cardinal is thinner 

than the other two cardinals and is pointed at about 

midpoint. It parallels the posterior lateral tooth. The 

right posterior cardinal is not grooved in the strict sense 

of the word, but has a flange that looks like a deformity. 

However, examination of 11 right valves of C. (M.) 

nimbosa has shown that the posterior cardinal on all 

right valves has an anterior flange. The right posterior 

cardinal consistantly shows a slight groove along the 

anterior side at the highest part of the tooth, with the 

part of tooth anterior to the groove lower than the 

posterior part. The right posterior lateral is thin and 

blade like. 

The anterior lateral of the left valve of C. (M.) nimbosa is a prominent, somewhat triangular, pointed 

projection. The anterior cardinal is very thin except at 

the ventral margin where it thickens; its anterior edge 

is flat and almost perpendicular to the beak. The middle 

cardinal is thick and curved with the thickest portion at 

the ventral end. The posterior cardinal, which resembles a lateral tooth, is thin, bladelike, and long. It 

extends along the dorsal margin to a point just above the 

middle cardinal tooth where it forms a socket to receive 

the right posterior cardinal. 

Callista (Macrocallista) pittsburgensis Dall 

Plate 12, figures 3, 5-11, 13 

Callista pittsburgensis Dall, 1900, Wagner Free Inst. Sci. Trans., v. 3, 

pt. 5, pl. 36, fig. 22. 

Meretrix (Callista) pittsburgensis Dall, 1900, Wagner Free Inst. Sci. 

Trans., v. 3, pt. 5, pl. 43, fig. 15. 

Macrocallista pittsburgensis (Dall). Dall, 1903, Wagner Free Inst. Sci. 

Trans., v. 3, pt. 6, p. 1253. Clark, 1918, California Univ. Dept. 

Geology Bull., v. 11, p. 146. Clark, 1925, California Univ. Pubs., 

Dept. Geol. Sci. Bull., v. 15, p. 92, pl. 18, fig. 9; pl. 19, figs. 4, 5. Clark, 

1932, Geol. Soc. America Bull., v. 43, p. 816, pl. 19, figs. 1, 2. Weaver, 

1942, Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 175-176, 

pl. 32, fig. 7; pl. 41, figs. 4, 7, 10, 14. Hickman, 1969, Oregon Univ. 

Mus. Nat. Hist. Bull. 16, p. 43, pl. 3, figs. ~14. 

Callista pittsburgensis is of moderate size, subovate in 

outline, and sculptured with bunched concentric lines. 

It is elongate posteriorly with a subdued angulation; the 

anterior end is evenly rounded. The beaks are situated 

one-fourth to one-fifth the distance from the anterior 

end. The shell is usually brown; Dall (1903, p. 1253) 

attributed this to the preservation of the periostracum, 

which seems reasonable considering the tight adherence of the periostracum on Holocene species. A few 

specimens lack the subdued posterior angulation and 

are higher in proportion to length than the average 

specimen (pl. 12, fig. 8). These specimens are considered 

to represent normal variation within the species. The 

external ligament platform is commonly preserved. The 

elongate lunule is demarcated by an incised line; it is 

smooth because the concentric lines sculpturing the rest 
CLASS PELECYPODA 49 

of the shell do not cross it. The hinge of C. pittsburgensis 15545, 15583, 15586, 15588, 18638, 21612, M3856, 

differs from the type species of Macrocallista, C. M3857, M3858, M3867, M3868, cf. M3869, M3871, 

nimbosa. The posterior cardinal tooth of the right valve M3872, M3878. 

of C. pittsburgensis is deeply grooved, whereas this Occurrence elsewhere.-Poul Creek Formation (midtooth of C. nimbosa is not grooved; instead it has a small die Oligocene to early Miocene), Alaska; Lincoln Creek 

flange on the anterior side. The middle and anterior Formation (late Eocene to early Miocene), Washington; 

right cardinals slant toward the anterior end rather Alsea Formation (early to late Oligocene), Eugene 

than being perpendicular to the beak; the socket Formation (early and middle Oligocene), and Tunnel 

bordered by the two anterior laterals is not parallel to Point Sandstone (middle Oligocene), Oregon; 

the dorsal hinge margin, and both the anterior laterals Kreyenhagen Shale (Eocene and early Oligocene), 

are more prominent on C. pittsburgensis than on C. Kirker Tuff (middle and late Oligocene), California. 

nimbosa. The left valve of C. pittsburgensis has an Possibly in Alegria Formation (middle Oligocene), 

anterior lateral that is smaller, thinner, and less California. 

prominent than on C. nimbosa; the anterior cardinal is Family MACTRIDAE 

not perpendicular to the beak but slants toward the Genus Spisula Gray 

anterior margin; the middle cardinal projects over the Spisula Gray, 1837, Mag. Nat. Hist., new ser., v. 1, p. 372. 

ventral edge of the hinge plate and seems to be very Type species-By subsequent designation (Gray, 

slightly grooved; the anterior cardinal is essentially 1847, Zool. Soc. London Proc., no. 179, p. 185), Mactra 

similar to that of C. nimbosa. In both valves of C. solida Montagu =Cardium solidum Linne. Holocene, 

pittsburgensis, the hinge plate and attendant dentition Atlantic. 

in specimens of similar size are more restricted to the Subgenus Mactromeris Conrad 

area below the beak. The anterior end of the shell of C. Mactromeris Conrad, 1868, Am. Jour. Conchology, v. 3, app., pt. 3, p. 

nimbosa is much more produced. Perhaps the most 45. 

striking difference between the hinges of the two species Type species.-By subsequent designation (Stoliczka, 

is the grooved right posterior cardinal of C. 1871, Geol. Survey India, Palaeontologia Indica, ser. 6, 

pittsburgensis. C. hornii (Gabb) from the Eocene of v. 3, p. 16), Mactra ovalis Gould, Holocene, North AtCalifornia (Stewart, 1930, pl. 17, fig. 7) and C. lantic. 

cathcartensis (Weaver) from the late Oligocene and Spisula (Mactromeris) pittsburgensis Clark 

early Miocene of Washington have a grooved right Plate 14, figures 3-8, 10, 11 

posterior cardinal. C. densa Moody (1916, p. 58) from the Spisula pittsburgensis Clark, 1925, California Univ. Pubs., Dept. 

Pliocene of California is said to have bifid posterior Geol. Sci. Bull., v. 15, p. 101-102, pl. 17, figs. 2, 4. Tegland, 1933, 

cardinals in both valves. Although the differences California Univ. Pubs., Dept. Geol. Sci. Bull., v. 23, p. 120-121. 

Weaver, 1942, Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 

between C. pittsburaensis o and C. nimbosa are consi- 235 ,p. 1 54 , fi g. 9 ;p. 1 61 , fi gs. 1 4 , . H. 1c k man, 1969 , o u regon n1v. · M us. 

dered significant, it is my opinion that they could be the Nat. Hist. Bull. 16, p. 51, pl. 5, fig. 1. 

result of the evolution of the genus, and that the Spisula pittsburgensis is subovate in outline, small to 

Pitarinae need much more study before it would be moderate sized, and thin shelled. The posterior dorsal 

practical to propose, if necessary, a new subgeneric margin is straight except for a slightly inflated esname. cutcheon. The posterior end is evenly rounded. A ridge 

Lectotype.-VSNM 107396 is herewith designated extends from the umbo to the posterior ventral margin. 

the lectotype (pl. 12, fig. 13). The lectotype is one ofthe The anterior dorsal margin is inflated in the lunule 

two specimens originally figured by Dall (1900, pl. 36, area; the anterior end is slightly pointed. There is little 

fig. 22). The figured paratype (pl. 12, fig. 11) has been variation in size, outline, and degree of inflation in this 

assigned catalogue number USNM 107399. species. 

Type locality.-Pittsburg, Columbia County, Oreg. The right anterior cardinal is thin, bladelike, and 

Sec. 23, T. 5 N., R. 4 W., Vernonia quadrangle. Pittsburg protrudes well beyond the hinge plate; it is fused to the 

Bluff Formation (middle Oligocene). dorsal margin of the shell. The right posterior cardinal 

The posterior elongation and anterior location of the is thin, does not protrude as far as the anterior cardinal, 

beaks of C. pittsburgensis separate it from other species. and borders the anterior end of the resilifer, which is 

Locally very abundant, it occurs in great numbers in moderately deep and oblique. The anterior and possome rocks with only a few other forms intermingled but terior paired laterals are thin; each are bordered with a 

with no apparent life orientation. The mineralized moderately shallow dorsal pit and separated from one 

ligament is preserved on some specimens (M3858). another by a very deep pit. The left cardinal has the 

Localities.-VSGS 2714, 5394, 15264, 15264a, b, e, I shape of an inverted V, is small, and projects far beyond 

15310, 15310a, c, f, g, j, i, 15311, 15519, 15530, 15537, the hinge plate. The single anterior and posterior 
50 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

laterals are thin, the posterior one bladelike, the anterior one rounded and more produced. 

Holotype.-SU 5205. 

Type locality.-UW 476. From bluffs along highway 

near old mill at Pittsburg, Columbia County, Oreg. 

Pittsburg Bluff Formation (middle Oligocene). 

Spisula eugenensis differs from S. pittsburgensis by 

having an anterior umbonal ridge (Hickman, 1969, p. 

50--51). 

Localities.-USGS 2714, 5394, 15264, 15264a-e, 

15310, 15310a-~i, 15311,15312,15499,15532,15545, 

15586, 15588, 18638, ~3856, ~3858, ~3860, ~3869, 

~3871, M3872, ~3877, M3878. 

Occurrence elsewhere.-Poul Creek Formation (middle Oligocene to early Miocene), Yakataga District, 

Gulf of Alaska; Quimper Sandstone of Durham (1942) 

(early and middle Oligocene) and Blakeley Formation of 

Weaver (1912) (late Oligocene and early ~iocene), 

Washington; Alsea Formation (early to late Oligocene), 

Eugene Formation (early and middle Oligocene), Tunnel Point Sandstone (middle Oligocene), Oregon. 

Spisula (Mactromeris?) veneriformis Clark 

Plate 14, figures 1, 2, 9 

Spisula veneriformis Clark, 1925, California Univ. Pubs., Dept. Geol. 

Sci. Bull., v. 15, p. 103, pl. 16, figs. 1-3. Weaver, 1942, Washington 

Univ. (Seattle) Pubs. Geology, v. 5, p. 235, pl. 54, fig. 9; pl. 61, figs. 1, 

4. 

Clark describes the hinge of this species as follows: 

Hinge plate rather heavy; resilifer pit deep, the two cardinals in the 

right valve well developed, both reaching nearly across hinge plate; 

anterior cardinal close to and connected with anterior dorsal margin. 

Cardinal in right valve apparently not deltoid. The deltoid tooth is a 

character common to almost all genera of the Mactridae; but in this 

species the cardinal consists of one heavy process extending from a 

beak to anterior edge of hinge plate. 

Keen (1969, p. N595) describes the hinge of the 

~actracea as having one inverted V-shaped cardinal 

tooth in the left valve and two cardinals in the right 

valve. 

The right valve is here considered to have two cardinal teeth, rather than one deltoid tooth. The few 

specimens of Spisula veneriformis in the collections are 

internal molds with no shell remaining. Rubber impressions were made of all specimens retaining a mold 

of the hinge. An impression of a right valve was obtained (pl. 15, fig. 2), and although the impression is not 

perfect, the right valve may have had two cardinal teeth 

originally. In examining Holocene specimens of S pis ula 

(Mactromeris) in the collections, I found that in at least 

half the specimens of right valves the posterior cardinal 

was either completely destroyed or broken. Perhaps 

when the valves of this form are disarticulated, the 

fragile right posterior cardinal is destroyed. This may 

be the explanation for Clark (1925, p. 103) saying that 

the right valve had but one tooth. 

Holotype.-UC~P 54. 

Type locality.-SU N.P. 42. In shale and sandstone in 

sea cliff at Tunnel Point, west of Coos Bay, Oreg. Tunnel 

Point Sandstone (middle Oligocene). 

This species is very large and shaped more like a 

venerid than a mactrid. The beaks are high and about a 

third the distance from the anterior margin. The venerid outline distinguishes S. veneriformis from other 

species of Spisula. 

Localities.-USGS 15516, 15532, 15537, 15544, 

15588. 

Occurrence elsewhere.-Tunnel Point Sandstone 

(middle Oligocene), Oregon. 

Family MESODESMATIDAE 

Subfamily DAVILINAE 

Genus Ervilia Turton 

Ervilia Turton, 1822, British Bivalves, p. 56. 

Type species.-Mya nitens ~ontagu. Holocene, 

Florida. 

?Ervilia oregonensis Dall 

Plate 16, figures 2, 5 

Ervilia oregonensis Dall, 1898, Wagner Free Inst. Sci. Trans., v. 3, pt. 

4, p. 916, pl. 33, fig. 16. Weaver, 1942, Washington Univ. (Seattle) 

Pubs. Geology, v. 5, p. 243, pl. 56, fig. 4. 

The single specimen is presumably conspecific with 

Ervilia oregonensis Dall. The hinge, though exposed, is 

not sufficiently well preserved for generic identification. 

The specimen is more quadrate in outline than the 

Holocene specimens of Ervilia. The shell is very thin 

and concentrically sculptured, and the ligament is 

presumably obsolete. 

Holotype.-USN~ 107406. 

Type locality.-Nehalem River, Columbia County, 

Oreg. Presumably from the Pittsburg Bluff Formation, 

middle Oligocene. 

Locality.-USGS 18638. 

Family TELLINIDAE 

Subfamily TELLININAE 

Genus Tellina Linne 

Tellina Linne, 1758, Systema naturae, ed. 10, p. 674. 

Type species.-By subsequent designation (Schmidt, 

1818, Versuch Conchylien-Sammlung, p. 51, 177), 

Tellina radiata Linne. Holocene, West Indies. 

Subgenus Eurytellina Fischer 

Eurytellina Fischer, 1887, Man. de Conchyliologie et de Paleont. 

Conch., p. 1147. 

Type species-By monotypy, Tellina punicea Born. 

Holocene, West Indies. 

Tellina (Eurytellina) aduncanasa Hickman 

Plate 11, figures 7-12 

Tellina aduncanasa Hickman, 1969, Oregon Univ. Mus. Nat. Hist. 

Bull. 16, p. 55-56, pl. 6, figs. 7-12. 

Tell ina aduncanasa is of moderate size and elongate; 

the length about twice the height. The anterior end is 

evenly rounded, the posterior end sharply attenuated. 

The posterior end is strongly beveled and set off by a 
CLASS PELECYPODA 51 

ridge at the anterior side. The entire surface bears fine 

incised lines that change direction at the anterior edge 

of the beveled part, making an angle of about 90°. 

Hickman (1969, p. 56) describes the hinge of both 

valves. 

Holotype.-VO 27262. 

Type locality.-VO 2567. In well-indurated 

brownish-gray tuffaceous sandstone and siltstone on 

east side of Oregon State Highway 4 7, 0.2 mile north of 

junction with Pittsburg-Scappoose Road, N% sec. 23, T. 

5 N., R. 4 W., Vernonia quadrangle, Columbia County, 

Oreg. Pittsburg Bluff Formation, (middle Oligocene). 

Localities.-VSGS 2714, 2722, 15264, 15264b, c, e, 

15310, 15310b, 15312,15544,15586, 15588,~3858;c£ 

15311. 

Occurrence elsewhere.-Eugene Formation (early 

and middle Oligocene), Oregon. 

Tellina? pittsburgensis Clark 

Plate 11, figures 1-6 

Tellina pittsburgensis Clark, 1925, California Univ. Pubs., Dept. 

Geol. Sci. Bull., v. 15, p. 95, pl. 12, figs. 8, 9. Weaver, 1942, 

Washington Univ. (Seattle) Pubs. Geology, v. 5, p. 200-201, pl. 48, 

fig. 4. Hickman, 1969, Oregon Univ. Mus. Nat. Hist. Bull. 16, p. 55, 

pl. 6, figs. 3-6. 

Tellina? pittsburgensis is of small size, subovate in 

outline, and very thin shelled. The anterior end is 

evenly rounded and the posterior end is slightly produced. The shell bears fine, bunched concentric lines 

that are deflected near the posterior end. Just anterior 

to this deflection is a slight sulcus. The shell is moderately inflated. The left valve is slightly larger than 

the right, and both valves are deflected to the right at 

the posterior end. 

Holotype.-SV Paleo. Type Coli. 46. 

Type locality.-SV loc. NP 5. In sandstone cliff along 

Nehalem River near old Pittsburg lumber mill,just past 

bridge below Vernonia, Oreg. Pittsburg Bluff Formation (middle Oligocene). 

Because ofthe state of preservation of the specimens, 

the small size of the species, and the very thin shell, it 

has not been possible to prepare a perfect hinge. Several 

hinges were exposed and two are figured (pl. 11, figs. 1, 

2) but still some details are not clear. No lateral teeth 

could be identified without qualification, although there 

is a suggestion of a lateral tooth on one of the valves. 

Hickman (1969, p. 55) found well-developed lateral 

teeth on specimens identified as T. pittsburgensis from 

the Eugene Formation. Her findings suggest that the 

specimens from the Eugene Formation may not be 

conspecific with the Pittsburg Bluff specimens. The 

following characters were noted on the hinges exposed: 

On the right valve there are two cardinal teeth, the 

posterior one thick and bifid, the anterior one very small 

and thin. A possible lateral tooth is posterior to the 

cardinals but near them; no lateral tooth was found 

anterior to the cardinals. On the left valve are two 

cardinal teeth, the posterior thick and bified and the 

anterior one very small and thin. A possible lateral 

tooth is anterior to the cardinal teeth. 

A closely related form occurs in the Poul Creek 

Formation (middle Oligocene to early ~iocene), 

Yakataga and Katella Districts, Gulf of Alaska. 

Localities.-VSGS 2714, 15264, 15264b, c, 15310, 

15310d, 15519, 15530, 15586, 15588, 18638, ~3871, 

~3877, c£ ~3878. . 

Occurrence elsewhere.-Gries Ranch Formation 

(early Oligocene), Quimper Sandstone of Durham 

(1942) (early and middle Oligocene), Washington; 

Eugene Formation (early and middle Oligocene) and 

Tunnel Point Sandstone (middle Oligocene), Oregon; 

Tumey Formation of Atwill (1935) (Oligocene), 

California. 

Family SOLENIDAE 

Genus Solen Linne 

Solen Linne, 1758, System naturae, ed. 10, p. 672. 

Type species.-By subsequent designation 

(Schumacher, 1817, Essai d'un nouveau systeme des 

habitations des vers testaces, p. 124, pl. 6, fig. 3), Solen 

vagina Linne. Holocene, Europe. 

Solen townsendensis Clark 

Plate 13, figures 3-5 

Solen (Plectosolen) townsendensis Clark, 1925, California Univ. 

Pubs., Dept. Geol. Sci. Bull., v. 15, p. 97-98, pl. 22, figs. 7, 10. 

Solen townsendensis Clark. Effinger, 1938, Jour. Paleontology, v. 12, 

p. 372-373. Weaver, 1942, Washington Univ. (Seattle) Pubs. 

Geology, v. 5, p. 225, pl. 53, figs. 1, 9. 

?Solen sicarius Gould. Hickman, 1969, Oregon Univ. Mus. Nat. Hist. 

Bull. 16, p. 63-64, pl. 8, figs. 5, 7, 9. 

Solen townsendensis is thin shelled. The few 

specimens in the collections are small. The anterior end 

is truncated at the dorsal margin and evenly rounded at 

the ventral margin. It lacks a sulcus but it has a slight 

broad depression. The posterior end is almost evenly 

rounded with a slight flattening in the midregion of the 

shell. 

Holotype.-SV 51. 

Type locality.-SV Loc. NP 272. In bluffs along 

Skamokawa River above big bend 1 mile east of junction 

of main and middle forks, Skamokawa, Wash. Gries 

Ranch Formation (early Oligocene). 

Hickman (1969, p. 63-64) assigned an Oligocene 

Solen from the Eugene Formation (early and middle 

Oligocene), Oregon, to the ~iocene to Holocene species 

Solen sicarius Gould, because she felt it impossible to 

determine the affinities of the fossil species without 

intensive study. One well-preserved specimen in the 

Pittsburg Bluff collections (pl. 8, figs. 10, 11) makes 

some comparison with S. sicarius possible. In the ratio 

of height to length, the fossil form is identical to S. 
52 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

sicarius. However, both the anterior and posterior ends 

of S. townsendensis are rounded as in Solen rosaceus 

Carpenter, a Holocene species, rather than truncated as 

in S. sicarius. S. rosaceus is much more elongate in 

proportion to height than the Oligocene species. It 

seems probable that the Oligocene species is not conspecific with the Holocene forms examined, and the 

name Solen townsendensis is retained for the fossil 

form. 

Solen conradi Dall (1900, p. 953), a Miocene species, 

has a concave dorsal margin and is more sharply 

truncated at the posterior end than S. townsendensis. 

Localities.-USGS 2714, 5394, 15264, 15310, 15537, 

15586, M3858, M3860, M3871, M3872. 

Occurrence elsewhere.-Gries Ranch Formation 

(early Oligocene), Quimper Sandstone of Durham 

(1942) (early and middle Oligocene), Washington; Alsea 

Formation (early to late Oligocene) and possibly in the 

Eugene Formation (early and middle Oligocene) and 

the Tunnel Point Sandstone (middle Oligocene), Oregon. 

Genus Solena Morch 

Solena Morch, 1853, Cat. Conch. Yoldi, pt. 2, p. 7. 

Type species.-By subsequent designation (Stoliczka, 

1871, Geol. Survey India, Palaeontologia Indica, ser. 6, 

p. xvi), Solen obliquus Spengler. Holocene, Caribbean. 

Subgenus Eosolen Stewart 

Eosolen Stewart, 1930, Acad. Nat. Sci. Philadelphia Spec. Pub. 3, p. 

290-291. 

Type species.-By original designation, Solen 

plagiaulax (Cossmann). Middle Eocene, France. 

On the basis of a distinct umbonal furrow, Solena 

(Eosolen) columbiana (Weaver and Palmer) (1922, p. 24, 

pl. 10, fig. 3) was placed inEosolen by Stewart (1930, p. 

292). The following species should also be assigned to 

this subgenus: 

Solena lincolnensis (Weaver), 1916a, p. 43, pl. 2, figs. 

9--12, Oligocene, Washington. 

Solena clarki (Weaver and Palmer), 1922, p. 23-24, pl. 

9, fig. 16, Eocene, Washington. 

Solena eugenensis (Clark), 1925, p. 98, pl. 22, fig. 1, 

Oligocene, Oregon. 

Solena (Eosolen) eugenensis (Clark) 

Plate 13, figures 1, 2, 6 

Solen eugenensis Clark, 1925, California Univ. Pubs., Dept. Geol. Sci. 

Bull., v. 15, p. 98, pl. 22, fig. 1. 

Solenaeugenensis (Clark). Weaver, 1942, Washington Univ. (Seattle) 

Pubs. Geology, v. 5, p. 230, pl. 53, figs. 14, 15. 

Solena (Eosolen) eugenensis (Clark). Hickman, 1969, Oregon Univ. 

Mus. Nat. Hist. Bull. 16, p. 63, pl. 7, figs. 11, 12. 

Solena eugenensis is a large moderately thick-shelled 

form with a strong anterior sulcation. The shell flares 

outward at the anterior gape. The anterior margin is 

truncated at an angle of about 30° from the perpendicular; the posterior angulation is nearly perpendicular. The shell is smooth except for bunched concentric lines. Parts of the mineralized ligament are 

preserved on some specimens. 

Holotype.-UCMP 30338. 

Type locality.-UC 4182. New City Reservoir, 

Eugene, Oreg. Eugene Formation (early and middle 

Oligocene). 

Solena eugenensis is higher in proportion to length 

and has a lower anterior angulation than S. Iorenzana 

Wagner and Schilling (1923, p. 256, pl. 47, fig. 1) from 

the Oligocene of California. 

A closely related form occurs in the Poul Creek 

Formation (middle Oligocene to early Miocene), Alaska. 

Localities.-USGS 2714, 5394, 15264b, 15278, 

15310a, 15312, 15499, 15519, 15529, 15537, 15544, 

15586, 15588, M3858, M3867, M3868, M3872; cf. 

M3871, cf. M3878. 

Occurrence elsewhere.-Lincoln Creek Formation 

(late Eocene to early Miocene), Washington; Eugene 

Formation (early and middle Oligocene), and possibly in 

the Alsea Formation (early to late Oligocene) and in the 

Tunnel Point Sandstone (middle Oligocene), Oregon. 

Family HIATELLIDAE 

Genus Panopea Menard de la G~oye 

Panopea Menard de la Groye, 1807, Memoire sur un nouveau genre de 

coquille bivalve-equivalve de la famille des Solenoides, p. 16, 31 

(Dall, 1912, Malacological Soc. Proc., v. 10, p. 34-35). Vokes (1967, 

p. 326) cites Panopea Menard de la Groye (April?, 1807) as the 

nomenclatorially valid name predating Panope Menard de la Groye 

(August, 1807). A decision of the I.C.Z.N. for the emended spelling, 

Panope, is pending. 

Type species .-By subsequent designation (Schmidt, 

1818, Versuch Conchylien-Sammlung, p. 47, 177), Mya 

glycimeris Born (cited by Menard de la Groye, 1807, p. 

32, in synonymy of Panope aldrovandi). Holocene, 

Mediterranean Sea. 

Panopea snohomishensis Clark 

Plate 15, figure 5 

Panope snohomishensis Clark, 1925, California Univ. Pubs., Dept. 

Geol. Sci. Bull., v.15, p.105, pl. 10, fig. 2. Weaver, 1942, Washington 

Univ. (Seattle) Pubs. Geology, v. 5, p. 261-263, pl. 59, figs. 3, 10. 

Panopea snohomishensis is moderate sized, subovate, 

and high in proportion to length. The anterior end is 

evenly rounded and the posterior end is attenuated and 

evenly rounded to moderately truncated (pl. 15, fig. 5). 

The posterior end is smaller than the anterior end. The 

beaks are slightly anterior of the midportion of the 

shell. The hinge line is not straight; instead it slopes 

from the beaks to the anterior and posterior ends of the 

shell and thus is not parallel to the ventral margin. The 

beaks are prominent and small. The hinge is not exposed. 

Holotype.-SU 59. Paratype SU 60. 

Type locality.-SU loc. N.P. 146. In Northern Pacific 

Railway cut one-half mile north of Cathcart Station, 
CLASS PELECYPODA 53 

Snohomish County, Wash. sec. 6, T. 27 N., R. 6 E., 

Maltby quadrangle, Lincoln Creek Formation (late 

Eocene to early Miocene). 

This species is distinguished by its subovate outline, 

the slope of the dorsal margin, and the large anterior 

end. 

Panopea cf. P. snohomishensis is reported from the 

Poul Creek Formation (middle Oligocene to early 

Miocene), Alaska. 

Localities.-USGS 15264, 15516. 

Occurrence elsewhere .-Lincoln Creek Formation 

(late Eocene to early Miocene), Washington; Alsea 

Formation (early to late Oligocene) Oregon. 

Panopea ramonensis Clark 

Plate 15, figures 1-3 

Panope ramonensis Clark, 1925, California Univ. Pubs., Dept. Geol. 

Sci. Bull., v. 15, p. 106, pl. 10, figs. 2, 3. Weaver, 1942, Washington 

Univ. (Seattle) Pubs. Geology, v. 5, p. 263-264, pl. 59, fig. 11. 

Hickman, 1969, Oregon Univ. Mus. Nat. Hist. Bull. 16, p. 65, 68, pl. 

8, figs. 8, 12. 

Panopea ramonensis is elongate and subquadrate in 

outline. The hinge line is straight and parallels the 

ventral margin. The posterior and anterior ends are of 

equal size; the posterior end is broadly truncated and 

gaping and the anterior end is evenly rounded. The 

beaks are small but prominent, inturned, and anterior 

of the midpoint of the shell. In his original description, 

Clark (1925, p. 106) says, ~~A fairly broad, shallow 

depression or sinus between beak and lower angle of 

truncated posterior end; this zone of depression more 

noticeable on some specimens than on others." In the 

Pittsburg Bluff collections, the specimens with the shell 

intact do not show this sinus, whereas those from which 

the shell has exfoliated do. It seems possible that this 

sinus is simply the impression left at the boundary 

where thickened shell which forms the hinge line meets 

the thinner shell. Modeling clay was pressed into the 

shell of a Holocene specimen of Panopea abrupta and a 

~~sinus" was produced on the clay similar to that seen on 

internal molds of P. ramonensis. P. ramonensis is more 

elongate in proportion to height and is much smaller 

than P. abrupta. It differs from P. snohomishensis by 

having a straight hinge line and a medially located 

beak. 

Holotype.-UCMP 30330. Paratype: UCMP 30331. 

Type locality.-UC loc. 1131. One-halfmile southwest 

of town of Walnut Creek, on east side of OaklandAntioch Railway bridge, elevation 150 feet, Contra 

Costa County, Calif. San Ramon Sandstone (early 

Miocene?). 

Localities.-USGS 2714, 15310, 15310e, 15312, 

15499, 15519, 15586, 15588, M3871, M3872. 

Occurrence elsewhere .-Blakeley Formation of 

Weaver (1912) (late Oligocene and early Miocene), 

Eugene Formation (early and middle Oligocene), 

Oregon; San Ramon Sandstone( early Miocene?), Wygal 

Sandstone Member (late Oligocene) of the Temblor 

Formation, California. 

Family PERIPLOMATIDAE 

Genus Cochlodesma Couthouy 

Cochlodesma Couthouy, 1839, Boston Jour. Nat. Hist., v. 2, p. 170. 

Type species.-By monotypy, Anatina leana Conrad, 

Holocene, Nova Scotia to North Carolina, United 

States. 

Cochlodesma bainbridgensis Clark 

Plate 16, figures 4, 6--11 

Cochlodesma bainbridgensis Clark, 1925, California Univ. Pubs., 

Dept. Geol. Sci. Bull., v. 15, p. 86, pl. 13, figs. 3, 4. Tegland, 1933, 

California Univ. Pubs., Dept. Geol. Sci. Bull., v. 23, p. 112, pl. 6, figs. 

3, 4. Weaver, 1942, Washington Univ. (Seattle) Pubs. Geology, v. 5, 

p. 117, pl. 25, fig. 1, pl. 29, fig. 2. Durham, 1944, California Univ. 

Pubs., Dept. Geol. Sci. Bull., v. 27, p. 141. 

Cochlodesma bainbridgensis is small to moderate in 

size; it has a very thin fragile shell that is internally 

nacreous. The shell is sculptured with faint, concentric, 

slightly irregularly spaced undulations that do not 

resemble those present on Cyathodonta, a generic 

assignment considered for this species (Grant and Gale, 

1931, p. 255, footnote). On the hinge of a right valve, the 

condrophore is small, deep, subtriangular and directed 

posteriorly (pl. 16, fig. 9), closely matching that illustrated by Tegland (1933, pl. 6, fig. 3). The variation in 

outline of the four specimens figured (pl. 16, figs. 6, 8, 10, 

11) is so great that it seems useless to try to use this as a 

specific criterion. Some of the variation is undoubtedly 

caused by deformation but some of it may be inherent. It 

has not been possible to separate the Cochlodesma in 

the Pittsburg Bluff Formation from C. bainbridgensis; 

possibly C. bainbridgensis is a species with a long time 

range. The preservation of the specimens in the 

collections is such that is has not been possible to 

determine if C. bainbridgensis is inequivalve with the 

right valve more convex. 

Holotype.-SU 27. 

Type locality.-SU loc. N.P. 103. In outcrops of shaly 

sandstones along beach between south side of entrance 

to Port Blakeley and Restoration Point, Wash. Blakeley 

Formation of Weaver (1912) (late Oligocene and early 

Miocene). 

Paratype.-SU 28. Same locality as holotype. 

A closely related form occurs in the Alsea Formation 

(early to late Oligocene), Oregon. 

Localities.-USGS cf. 5392, 15278, 15519, 15583, 

15588, M3872. 

Occurrence elsewhere.-Poul Creek Formation (middle Oligocene to early Miocene), Yakataga District, 

Gulf of Alaska; Stepovak Formation of Burk (1965) 

(early and middle Oligocene), Coal Bay section, Alaska; 
54 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

Blakeley Formation of Weaver (1912) (late Oligocene 

and early Miocene), Washington. 

Family THRACIIDAE 

Genus Thracia Blainville 

Thracia Blainville, 1824, Dictionnaire des sciences naturelles, v. 32, 

p. 347. 

Type species.-By subsequent monotypy (Blainville, 

1825, Manuel de malacologie et de conchyliologie, p. 

660, removes his division B from Thracia, leaving but 

one species in the genus), Thracia corbuloides Blainville. Holocene, Mediterranean. 

Sowerby (1823, The Mineral Conchology of Great 

Britain, v. 5, pt. 1, p. 20) under the discussion of Mya 

mentions T hracia of Leach as a possible name to be 

applied to some forms he assigns to Mya. No particular 

species or figure is cited, and this reference to Thracia is 

considered a nomen nudum as listed by Vokes (1967, p. 

339). Thracia (Thracia) condoni Dall 

Plate 16, figures 1, 3 

Thracia condoni Dall, 1909, U.S. Geol. Survey Prof. Paper 59, p. 

135-136, pl. 19, fig. 5. Clark, 1918, California Univ., Dept. Geology 

Bull., v. 11, no. 2, p. 137, pl. 11, fig. 12; pl. 12, fig. 2. Tegland, 1933, 

California Univ. Pubs., Dept. Geol. Sci. Bull., v. 23, no. 3, p. 113, pl. 

6, fig. 5. Weaver, 1942, Washington Univ. (Seattle) Pubs. Geology, 

v. 5, p. 119, pl. 25, fig. 10; pl. 29, fig. 15. Durham, 1944, California 

Univ. Pubs., Dept. Geol. Sci. Bull., v. 27, no. 5, p. 141, pl. 13, fig. 6. 

Hickman, 1969, Oregon Univ. Mus. Nat. Hist. Bull.l6, p. 72-73, pl. 

9, figs. 10-14. 

Thracia condoni is usually of small to moderate size. 

It is not common in the Pittsburg Bluff Formation. The 

specimen illustrated is the largest in the collections; it 

measures 46.7 mm long (broken) and 34.7 mm high. The 

shell is smooth except for bunched concentric lines. The 

beaks are centrally located. The posterior end is elongate and the dorsal margin is almost straight. The 

ligament nymph and groove can be seen on the preserved part of the hinge illustrated on plate 16, figure 3. 

Parts of mineralized ligament are preserved on some 

specimens. Because of the thin shell, most of the 

specimens ofT. condoni are crushed and distorted, and 

many are molds from which the shell has exfoliated. On 

the best preserved specimens, the right valve, noticeably larger than the left valve, overlaps the ventral 

edge. On a specimen with a left valve about 19.4 mm 

high, the right valve extends 1. 7 mm beyond the ventral 

margin at the anterior end. On all specimens the beak 

on the right valve and the area along the dorsal edge of 

the anterior hinge have been abraded by the left valve. 

Holotype.-USNM 110460. 

Type locality.-Smith's quarry, Eugene, Oreg. 

Eugene Formation (early and middle Oligocene). 

T. condoni has a straighter posterior dorsal margin 

and is more elongate posteriorly than Thracia schencki 

Tegland (1933, p. 112-113, pl. 6, figs. 6--11). The umbos 

are lower on T. condoni, the shell less inflated, and the 

posterior end more elongate than on T hracia 

trapezoides Conrad (1849, p. 723, pl. 17, fig. 6a; Moore, 

1963, p. 84-85, pl. 26, fig. 3; pl. 31, fig. 6). 

Localities.-USGS 15264, 15278, 15310, 15519, 

15548, 15583, 15586, 15588. 

Occurrences elsewhere .-Poul Creek Formation 

(Oligocene and Miocene), Yakataga District, Gulf of 

Alaska; Stepovak Formation of Burk (1965)(early and 

middle Oligocene), Alaska; Quimper Sandstone of 

Durham (1942) (early and middle Oligocene), 

Washington; Eugene Formation (early and middle 

Oligocene), Alsea Formation (early to late Oligocene), 

Oregon; San Lorenzo Formation (Eocene and 

Oligocene), California. 

Class CEPHALOPODA 

Family NAUTILIDAE 

Aturia angustata (Conrad) 

Plate 15, figure 4 

Nautilusangustatus Conrad, 1849, U.S. Explor. Exped. Geology, v.lO, 

app. p. 728, atlas, pl. 20, figs. 5, 6. 

Nautilites angustatus (Conrad). Conrad, 1858, Acad. Nat. Sci. 

Philadelphia Jour., v. 3 (new ser.), p. 335. 

Aturia angustata (Conrad). Dall, in Diller, 1896, U.S. Geol. Survey 

17th Ann. Rept., pt. 1, p. 459,465,467,468. Dall, 1909, U.S. Geol. 

Survey Prof. Paper 59, p. 21. Schenck, 1931, California Univ. Pubs., 

Dept. Geol. Sci. Bull., v. 19, p. 457-462, pl. 69, figs. 1-3, pl. 70, figs. 

1-5, pl. 71, figs. 1, 3-8, pl. 72, figs. 1, 2, 5, 6, text figs. 4, 5, 7-9, 20-23, 

30, 33. Weaver, 1942, Washington Univ. (Seattle) Pubs. Geology, v. 

5, p. 551-552, pl. 102, figs. 1-7:10. Miller, 1947, Geol. Soc. America 

Mem. 23, p. 85-88, pl. 48, figs. 5, 6, pl. 88, fig. 1, pl. 90, figs. 1-3, pl. 

91, figs. 1-2, pl. 92, figs. 1, 2, 8, 9, pl. 93, figs. 3. 4. Moore, 1963, U.S. 

Geol. Survey Prof. Paper 419, p. 85-86, pl. 31, figs. 1, 5. Hickman, 

1969, Oregon Univ. Mus. Nat. Hist. Bull. 16, p. 101-102, pl. 14, fig. 

10. 

Aturia ziczac (Sowerby). Conrad, 1865, Am. Jour. Conchology, v. 1, p. 

150. Gabb, 1869, Paleontology of California, v. 2, p. 69. Dall and 

Harris, 1892, U.S. Geol. Survey Bull. 84, p. 223-224 (Not Nautilus 

ziczac Sowerby, 1812, Mineral Conch. Great Britain, v. 1, pl. 12, 

lowest fig.). 

Aturia c£ ziczac (Sowerby). Reagan, 1908, KansasAcad. Sci. Trans., v. 

22, p. 171. 

Aturia angustata has been described in detail by 

Schenck (1931, p. 457-462) and by Miller (1947, p. 85--

88). 

Type species.-Larger figured syntype, USNM 3610 

(Moore, 1963, pl. 31, fig. 1). This is the only specimen 

originally figured by Conrad (1849, pl. 20, fig. 5) that 

remains in the U.S. National Museum type collection. 

Type locality.-Astoria, Oreg. Astoria Formation 

(Miocene). 

The only specimen of A. angustata known from the 

Pittsburg Bluff Formation is the one figured on plate 15, 

fig. 4. It was collected and donated by Bruce Welton, 

from Portland State University, to whom I am indebted. 

Locality.-Type locality for the Pittsburg Bluff 

Formation, near Pittsburg, Oregon. (Bruce Welton, 

written commun., Feb. 16, 1973). 
CLASS CEPHALOPODA 55 

Occurrence elsewhere.-Early Oligocene to middle 

Miocene in the Coast Ranges of Washington, Oregon, 

and California. Lincoln Creek Formation (late Eocene 

to early Miocene) and Weaver's (1912) Blakeley 

Formation (late Oligocene and early Miocene), 

Washington; Eugene Formation (early and middle 

Oligocene) and possibly the Keasey Formation (late 

Eocene and early Oligocene), Oregon. 

U.S. GEOLOGICAL SURVEY FOSSIL LOCALITIES 

IN THE PITTSBURG BLUFF FORMATION, 

MIDDLE OLIGOCENE, NORTHWESTERN 

OREGON 

USGS Cenozoic 

locality 

No. 

Washington, 

D.C., Register 

2415 

2707 

2714 

2715 

2721 

2722 

Description 

Westport on Columbia River, 

about 24 mi east of Astoria. 

Sec. 4, T. 2 N., R. 4 W. 

Washington County. 

Pittsburg, Columbia County, sec. 23, 

T. 5 N., R. 4 W. 

Rock Creek, sec. 31, T. 5 N., R. 4 W., 

Columbia County. 

SW'4 sec. 27, T. 5 N., R. 3 W., 

Columbia County. 

Nehalem River, 4 mi above Mist, 

sec. 29, T. 6 N., R. 4 W., 

Columbia County. 

2723 Nehalem River near Mist, sec. 14, 

T. 6 N., R. 5 W., Columbia County. 

5394 Pittsburg road cut, Columbia County, 

NW14 sec. 23, T. 5 N., R. 4 W. 

15264 ______ East side of Oregon State Highway 47, 

15278 ------

approximately 600 ft north of 

junction of Oregon State Highway 4 7 

and Scappoose-Vernonia Road, 

Columbia County. 3,500 ft south of 

grid 2,660 and 5,000 ft west of grid 

820, U.S. Army Corps Engineers 

Vernonia quadrangle. 

Wolf Creek Highway (Oregon 2), 

third cut on north side of northwest 

and H. E. Vokes. 

junction of Buxton-Vernonia Road 

(Oregon State Highway 47). Locality 

is approximately % mi from junction. 

5,500 ft south of grid 2,635, 5,500 ft 

east of grid 910, U.S. Army Corp. 

Engineers Gales Creek quadrangle. 

15310 ______ First large roadcut on west side of 

Scappoose-Vernonia Road, south of 

cutoff to Wilark, Columbia County. 

15311 ______ Same locality as 15310, but 20ft 

stratigraphically lower. 

15312 _____ Cuts on east side of Wilson Lumber 

Company road, 0.4 mi south of 

Kenusky Creek, on east branch of 

Nehalem River. 6,200 ft south of 

grid 2,655; 2,600 ft east of grid 820, 

U.S. Army Corps Engineers 

Vernonia quadrangle. 

Collector Date 

collected 

Will Brown ?1891 

J. S. Diller ____________ 1895 

__________ do __________ 1895 

__________ do __________ 1895 

________ do __________ 1895 

__________ do __________ 1895 

__________ do _________ 1895 

G. A. Macready - 1910 

W. C. Warren -------- 1944 

W. C. Warren 1944 

and H. E. Vokes. 

H. Norbisrath 1944 

and H. E. Vokes. 

__________ do _________ _ 1944 

__________ do ________ _ 1944 

15457 ______ Cut on east side of abandoned road W. C. Warren _______ _ 1944 

grade paralleling Oregon Highway 

202; 0.2 mi north of south edge of 

Svenson quadrangle. 

15499 ______ Under United Railroad trestle, about R. M. Grivetti, 1944 

1 mi north of Buxton, Washington W. C. Warren, 

County. Trestle bears notation "U.R. and H. Norbisrath. 

Tr 399 & 35." At south end of Gales 

Creek quadrangle. 

USGS Cenozoic 

locality 

Description Collector 

No. 

15516 ______ Road cut on Vernonia-Scappoose Road W. C. Warren __ 

near divide. This is the first cut 

south of point where the road passes 

over the railroad tunnel. Vernonia 

quadrangle. 

15519 ______ Cut on line of United Railroad 2.0 mi W. C. Warren 

(airline) north of Buxton, Washington County. Cut is at north end of 

arcuate railroad trestle. Gales Creek 

quadrangle. 

and H. Norbisrath. 

15529 ______ Cut on south side of Vernonia- W. C. Warren 

15530 ------

15532 ------

15536 ------

15537 ------

15544 ------

15545 ------

15548 

15583 ------

Scappoose Road, 3.5 mi by road 

southeast of junction at Wilark, 

Columbia County. Vernonia 

quadrangle. 

Cut on north side of VernoniaScappoose Road, 5.0 mi by road 

southeast of junction at Wilark, 

Columbia County. Vernonia 

quadrangle. 

Cut on north side of VernoniaScappoose Road, 1.7 mi west of 

Chapman School, Columbia County. 

St. Helens quadrangle. 

North side of Scoggin Creek Road, 1.3 

1.3 mi west of junction with Oregon 

and W. C. Warren. 

State Highway 47. 

Cut on north side of VernoniaScappoose Road, 0.6 mi west of 

Chapman School, Columbia County. 

St. Helens quadrangle. 

Cut on curve of United Railroad. This 

__________ do _________ _ 

__________ do _________ _ 

R. M. Grivetti 

W. C. Warren _______ _ 

R. M. Grivetti, 

is first curve northeast of Buxton, H. Norbisrath, 

Washington County. 3,050 ft west of and W. C. Warren. 

grid 815,000 and 5,500 ft south of 

grid 263,500. U.S. Army Corps 

Engineers Vernonia quadrangle. 

North end of trestle over ravine. __________ do _________ _ 

Fossils from north bank below 

trestle, 5th railroad trestle north of 

Buxton, Washington County. 

Approximately % mi up Flora Road H. Norbisrath 

from Nehalem River Highway, and W. C. Warren. 

along poorly exposed bank and in 

roadbed where road ascends hillside. 

Cathlamet quadran~le. 

Prominent bluff of east side of Oregon H. Norbisrath --------

State Highway 47, 1.6 mi north of 

the junction with the St. Helens 

highway, Columbia County, Oreg. 

4,200 ft west of grid 820, 4,000 ft 

north of grid 2,260, Cathlamet 

quadrangle. 

15586 ______ North end of short, abandoned tunnel W. C. Warren, 

about 1h mi east of Westport, Clatsop 

County, Oreg., on south side of U.S. 

Highway 30. 700 ft west of grid 800, 

5,000 ft north of grid 2,865, 

Cathlamet quadrangle. 

D. Duncan, 

and H. E. Vokes. 

15588 ______ Cut in logging road along the head- H. Norbisrath _______ _ 

18638 -

waters of the second main tributary 

entering Coal Creek from the northeast of its junction with Pebble 

Creek. 3,900 ft west of grid 820, 

5,200 ft south of grid 2,650. 

Vernonia quadrangle. 

Type area of Pittsburg Bluff 

Formation. 

Ralph Stewart _______ _ 

18779 ______ Type area of Pittsburg Bluff Formation, E. James, 

WolfCreek Highway, north of P. D. Snavely, 

Vernonia. and W. W. Rau. 

Date 

collected 

1944 

1944 

1944 

1944 

1944 

1944 

1944 

1944 

1944 

1944 1 

1945 

1945 

1945 

1952 

21612 __ Pittsburg Bluff Formation. Oyster lens R. E. Stewart --------

with Acila about 30 ft above 

Molopophorus. 
56 OLIGOCENE MARINE MOLLUSKS FROM THE PITTSBURG BLUFF FORMATION IN OREGON 

USGS Cenozoic 

locality 

No. 

Menlo Park, 

Calif. Register 

Description Collector 

M3856 ______ Lat 45°51.7' N., long 123°13.4'., along E. J. Moore _________ _ 

private forest road 300 m northeast 

of junction of IG:>nusky Creek and 

East Fork of Nehalem River, 

Columbia County. Middle of Pittsburg Bluff Formation. 

M3857 ______ Lat 45°51.2' N., long 123°13.7' W., along __________ do __ _ 

private forest road 900 m southeast 

of junction of Kenusky Creek and 

East Fork of Nehalem River. 

Columbia County. Middle of 

Pittsburg Bluff Formation. 

M3858 ______ Lat 45°50.2' N., long 123°02.7' W., along __________ do _________ _ 

M3860 ______ 

M3866 ______ 

M3868 __ 

M3869 ______ 

M387L. ---

private forest road near divide 

between East Fork Nehalem River 

and North Scappoose Creek, 200m 

north of bench mark 1232. Columbia 

County. Near top of Pittsburg Bluff 

Formation. 

Lat 45°55.0' N., long 123°08.0' W., 

along private forest road 750 m 

northeast of bench mark 580, which 

is about 1 km north of Pittsburg on 

Oregon State Highway 47. Columbia 

County. Base of Pittsburg Bluff 

Formation. 

Lat 45°43.6' N., long 123°11.1' W., 

along Spokane, Portland, and Seattle 

Railroad, 200 m north of Hares 

Canyon. Washington County. Near 

top of Pittsburg Bluff Formation. 

Lat 45°43.4' N., long 123°11.1' W.; 

along Spokane, Portland, and Seattle 

Railroad, 200 m south of Hares 

Canyon. Washington County. Near 

top of Pittsburg Bluff Formation. 

Lat 45°43.3' N., long 123°11.1' W., 

along Spokane, Portland, and Seattle 

Railroad, 400 m south of Hares 

Canyon. Washington County. Near 

top of Pittsburg Bluff Formation. 

Lat 45°48.6' N., long 123°08.4' W., 

along logging road on south side of 

Coal Creek, 350 m east of first tributary to south. Columbia County. 

Upper middle of Pittsburg Bluff 

Formation. 

__________ do __________ 

_________ .do __________ 

_ _________ do __________ 

__ do __________ 

__________ do ______ 

M3872______ Lat 45°48.9' N., long 123°08.0' W., __________ do ____ _ 

along logging road 50 m east of first 

tributary to Coal Creek to north and 

1,000 m northeast of junction of the 

tributary with Coal Creek. Columbia 

County. Upper middle of Pittsburg 

Bluff Formation. 

M3874_. _____ Lat 45°51.5' N., long 123°09.0' W., __________ do _________ _ 

along logging road on south side of 

second valley north of Coon Creek, 

1.6 km east of Oregon State Highway 47 where it turns west to become 

the main street of Vernonia. 

Columbia County. Middle part of 

Pittsburg Bluff Formation. 

M3877 ______ Lat 45°5l.O'N., long 123°06.6' W., __________ do _________ _ 

from roadcut along East Fork of 

Nehalem River, 650 m northwest of 

confluence of Jim George Creek, and 

100 m south of main road. Columbia 

County. Middle of Pittsburg Bluff 

Formation. 

M3878______ Lat 45°52.4' N., long 123°07.5' W., __________ do _________ _ 

from roadcut along main road that 

follows East Fork of Nehalem River 

directly west of confluence of Dog 

Creek. Columbia County. Middle of 

Pittsburg Bluff Formation. 

Date 

collected 

1968 

1968 

1968 

1968 

1968 

1968 

1968 

1968 

1968 

1968 

1968 

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Page 

A 

Abbreviations ---- 3 

abrupta, Panopea _____ 53 

acala, Leda _ 43 

IAcharaxl willapaensis, Solemya _ 20 

Acila _ 14,18,20,21,42,pl.17 

decisa 3, 22 

gettysburgensis zone 3, 4 

nehalemensis _______ 24 

shumardi ____ 1, 2, 3, 4, 5, 6, 8, 21, 24, 28, 42, 43 

biozone _ 

Zone 

defined __ _ 

IAcila) gettysburgensis 

iTruncaci/a) 

nehalemensis ___ _ 

minima 

shumardi __ 

type locality 

(Acila) decisa, Nucula __ _ 

gettysburgensis, Aczla _ 

shumardi, Nucula __ 

Acrilla 

!Ferminoscala l becki 

dickersoni 

Acteocina chehalisensis 

Acteon 

cheha!isensis 

parvum __ _ 

sp ___ _ 

Acteonidae _ 

acutilineata, Lucinoma 

Addicott, W. 0., cited 

addicotti, Aforia 

aduncanasa, Tel/ina 

Tellzna IEurytellina) 

Aforia 

addicotti _ 

campbe/11 

clallamensis 

wardi __ _ 

wardi 

2,9 

1, 2. 5, 6, 8, 9, 23, 24 

43 

17, 18. 22, 43 

20, 21, 23, 28, 43 

28 

2, 14, 15, 16, 19; 21, 

23, 24, 26, 28, 42' pl. 8 

2 

42 

43 

42 

22 

----- 28 

28 

------- 40 

----- 17, 18, 20,40 

11, 15, 16, 26, 40. pl. 7 

28, 40, 41 

15, 41, pl. 7 

---- 40 

28,46 

23,24 

------ 38 

8, 21, 28, 50 

14, 15, 16, 26, 50, pl. 11 

17, 18, 19. 20,37 

38 

11, 15, 26. 37, pl. 7 

38 

16, 37 

38 

Agasoma acuminatum beds_ 

columbiana ___ _ 

columbianum _ 34 

Alaska Peninsula, Oligocene fossils 

albensis, Nucula 

-------- 8, 19 

42 

---------- 32 

52 

8, 24. 25, 28 

---------- 43,49 

a/bus, Polin ices_ 

aldrat•andi, Panope _ 

Alegria Formation 

Calif 

fauna ___ _ 

Algae, coralline __ _ 

Alsea Bay, Oreg 

Alsea Formation _______ _ 

mollusks 

Newport area 

Oreg 

Alvania 

Anatina leana 

An cilia 

angustata, Aturia 

angustatus. Nautilites __ 

Nautilus_ 

annulata, Lucinoma 

----------- 8, 24 

----------- 20 

------------ 9, 10 

------- 10, 36, 44 

23. 25, 28 

23, 28 

10, 32, 34, 37, 43, 45, 46, 47, 

48, 49, 50, 52, 53, 54 

21 

53 

23 

----- 15, 16, 54. pl. 15 

54 

54 

46 

INDEX 

[Italic page numbers indicate major references] 

Apolymetis __ 

Area ___ _ 

montereyana Zone 

nuculeus 

Architectonica 

bland a 

Architectonicidae __ _ 

arctica, Y oidia 

Page 

23 

21 

42 

---- 16, 17. 19, 20,29 

11, 15, 16, 26. 29, pl. 1 

29 

44 

IArenomya l kusiroensis, Mya __ 28 

Arroyo Ciervo area, Calif 9 

20 

--- 20 

4, 29, 30, 31, 43 

30, 31, 33, 36, 38, 45, 54 

Arthropoda ___ _ 

Asteroidea 

Astoria Formation _ 

Oreg 

Wash __ 

Astraea 

Astropecten sp 

45 

19 

_______ 20 

Aturia ___ _ 

angustata 

ziczac 

australis, Scalaria _ 

---- 16 

_ __ 15. 16, 54, pl. 15 

54 

30 

B 

bainbridgensis, Cochlodesma _ 14, 15, 16, 26, 53, pl. 16 

Barbatia __________ 21 

merriami Zone ____ _ 

Bastendorf [Bastendorff] Formation 

[Bastendorft] Shale __ 

Bastendorff Shale 

foraminifera _ 

mollusks __ _ 

southwestern Oregon __ 

Bathybembix __ 

becki. Acrilla !Ferminosca/a)_ 

bentsonae, Gemmula ___ _ 

bigelowii, Braarudosphaera 

Biozone, definition 

biplicatus, Molopophorus 

quadranodosum, Molopophorus _ 

4 

6, 24 

5, 6, 7 

22,23 

----- 8, 22 

22 

23 

29 

28 

28 

25 

35 

35 

bisectus. Dictyococcites 25 

Blakeley beds 6 

Blakeley Formation, Oreg 53 

Wash___ 10. 30, 32. 36, 39, 43, 44, 45, 46, 47, 

Blakeley horizon 

Stage __ 

50, 54, 55 

4, 5 

7,9 

blakeleyensis. Turritella diversilineata _____ 30 

blanda, Architectonica 11. 15, 16, 26, 29. pl. 1 

borealis. Cardita 45 

IBoreoscala) condoni. Epitoniwn 

condoni eugenense, Epitonium _ 

oregonensis, Epitonium 

keaseyense, Epitonium 

Braarudosphaera bigelowii 

Brisaster 

maxim us 

Brisingid sp __ 

28 

28 

28 

31 

25 

19 

---- 20 

20 

Bruclarkia __ 

columbiana 

columbianum 

vokesi 

16, 19, 20, 22, 34 

1, 2. 5, 6, 9. 11, 14, 15, 21, 23, 

24, 26, 28, 34. pl. 3 

----- 8. 28 

brunnea, Natica __ _ 

Buccinidae 

Bukry, David, cited 

Bulla lignaria 

Bullia IMolopophorusl striata 

28 

32 

35 

24,25 

41 

---- 35 

Page 

c 

California. Oligocene fossils 19 

californica, Eosiphonalia ___________ 33, 34 

Callista _____________________________ 18, 19, 20,48 

cathcartensis ___ 49 

densa 49 

hornii __ 49 

nimbosa 49 

pittsburgensis 1, 4, 5, 6, 8. 21, 23, 28, 48, 49 

sp _ 28 

IMacrocallista) ______ 17 

nimbosa 48 

pittsburgensis ____ 3, 15, 16, 19, 26, 48, pl. 12 

iCallista) pittsburgensis, Meretrix ___ 48 

Calyptraea ________________________________ 22, 23 

diegoana _____ ____________ _ __ 28 

sookensis 

Calyptraeidae __ 

------- 28 

------ 31 

campbelli. Aforia ___ 11, 15, 26, 37, pl. 7 

Canada de Santa Anita, Calif ___________________ 23 

Cancellaria ___ 20, 22 

sp 

Cardiidae 

Cardiomya __ 

Cardita borealis 

Carditamerinae __ _ 

Carditidae 

Cardium cooperii lorenzanum 

lorenzanum 

semiasperum __ 

solidum 

carinata, Spirotropis 

Ca.ryophyllia sp ___ _ 

castrensis, Nucula __ 

cathcartensis. Callisto 

Centroscymnus _ 

Cephalopod __ _ 

Cephalopoda __ 

Chehalis River, Wash __ _ 

chehalisensis, Acteocina __ _ 

Acteon 

Priscofusus _________ _ 

Yoldia IPortlandella) 

C hiasmolith us oamaruensis 

chione, Venus 

Cibicides hodgei ___ -

Clallam Formation 

Clallam Stage 

clallamensis, Aforia 

wardi, Aforia 

20 

--------- 47 

----- 20, 22 

------- 45 

--------- 45 

------- 45 

------- 47 

47 

47 

49 

39 

20 

42 

49 

17 

----- 15, 16 

--- 54 

------- 47 

40 

11, 15. 16, 26, 40, pl. 7 

------- 36 

----------- 20 

25 

--- 48 

-- 8 

clarki, Pitar (Lamelliconcha) ____ _ 

3 

9 

38 

16, 37 

-------- 28 

Solen a 

Clatskanie, Oreg 

clausa, Cryptonatica 

Natica __ 

Clavella gravida 

Clavinae __ 

--------- 52 

--------------------- 7, 35 

31 

31 

34 

------- 39 

(Cnestrium) oregona, Yoldia 44 

--- 7, 18, 19 

37 

------ 31 

8 

----- 9. 25 

25 

25 

------- 25 

17,18,20,53 

Coal ___________ _ 

Coal Creek. Oreg ______ _ 

Coaledo Formation. Oreg 

Coast Ranges, California 

Coccoliths 

planktonic _ 

Coccolith us eopelagicus 

pelagicus __ 

Cochlodesma 

61 
62 

Cochlodesi1Ul---Continued. 

bainbridgensis __ 

cocoaensis. Uvigerina 

Coelenterata _ 

colimana, Opalia __ 

Collections, preparation 

Columbia County, Oreg., 

Page 

14. 15. 16, 26, 53. pl. 16 

---- 8 

20 

31 

2 

stratigraphic section ___ _ --- 2. 5 

columbiana. Agasoma _ ----- 3 

Bruclarkia 

Drillia 

Lucina __ 

Lucinoma 

Solena IEosolen I 

Taranis _ 

Thesbia 

Turcicula _ 

---- 1. 2, 5, 6. 9, 11, 14. 15, 21, 

23, 24. 26, 28, 34. pl. 3 

----- 38. 39 

46 

8. 14, 15, 16, 26, 45, pl. 10 

----------- 52 

11, 14. 15, 26, 38. pl. 7 

38 

--- 29 

columbianum, Agasoma 

Bruclarkia 

Phacoides _ 

------ 34 

8. 28 

45 

condoni, Epitonium IBoreoscala 1 28 

eugenense, Epttonium fBoreoscala 1 ___ 28 

oregonensis, Epitonium <Boreoscala I ---- 28 

Thracia _ 21. 28. 54 

(Thracial 14, 15. 16. 26. 54, pl. 16 

Conger eels 

Congridae 

conradi, Solen 

consimilis. Quercus __ _ 

Conus 

17 

17 

52 

21 

cooperii lorenzanum, Cardium _ 

Yoldia __ 

20,22 

---- 47 

44 

--- 19 

22, 25, 28. 50 

21 

--- 22 

54 

---- 36 

IKalayoldia I 

Coos Bay, Oreg 

Coral _ 

Garbis __ 

corbuloides, Thracia 

corrugatum, Perse 

Cowlitz Formation, Wash 

Crabs 

crenata, Turbo 

Crenella __ _ 

porterensis 

washingtonensis __ 

Crenellinae 

Crepidula 

pileum 

ungana 

31. 33 

17 

---- 30 

17, 18, 19. 22. 45 

11, 15, 16, 19, 26, 45, pl. 12 

45 

---- 45 

16, 17' 20, 31' 40 

---- 11, 1.5, 16, 26,31, pl. 1 

28 

iSpirocrypta I pileum __ 

Crinoid Beds. Keasey Formation 

31 

Crinoidea __ 

Crinoids 

Crustacea 

Crypta ISpirocrypta I pileum 

Cryptonatica _ 

clausa 

oregonensis 

pittsburgensis _ 

Cyathodonta 

Cyclicargolithus floridanus 

Cyclocardia 

hannai _ 

hannibali _ 

subtenta 

<Cyclocardia I hannibali 

ICyclocardia I hanniba/i, 

Cyclocardia 

Cylichnina __ 

turneri 

Cymric Shale Member 

CaliL_ 

Cypraea 

Dall. W. H .. cited 

dalli, Molopophorus __ 

Pi tar 

IPitarl __ 

Pitaria _ 

D 

20 

21, 22 

--- 20 

31 

17, 19. 20.31 

---- 31 

31 

11. 14. 15, 26. 31. pl. 1 

---- 53 

25 

-- 17, 18.20,45 

45 

- 45 

---- 45 

8, 11, 15. 16. 45, pl. 9 

8, 11. 15. 16. 45, pl. 9 

22 

------- 22. 28 

9, 25. 28 

34 

---- 19 

23 

6, 8, 24. 28. 35 

47 

15, 16, 26. 28. 47, pl. 12 

47 

Davilinae _ 

decisa. Acila 

INDEX 

Nucu/a ___ ___________ _ 

(Acila) ------- _ 

Page 

--50 

3, 22 

42 

----- 42 

d.ecussatus, Mytilus _____________________________ 45 

Deer Island, Oreg ______ ____________ _ __________ 7 

Delectopecten 

sp ---

densa, Callisto 

Dentaliidae __ 

Dentalium __ _ 

elephantinum 

ergastic urn ______ _ 

laneensis ____ _ 

--- 20, 21, 22 

------ 20 

--------- 49 

-- 41 

-------- 16. 41 

--------- 41 

-------------- 41 

---- 9, 42 

porterensis _ _____________ _ ________ 22 

IFissidentalium I ________________________ 17, 18 

laneensis ________ 14, 15, 16, 26, 28, 41, pl. 7 

Dentiscala ______________________________ 30 

<Dentiscalal, Opalia ____________________________ 18 

hertleini, Opalia __________ 11, 15, 16, 26, 30, pl. 3 

Diatoms ___________ _ ____________ 20 

dickersoni, Acrilla (Ferminoscala) ______________ 28 

Suavodrillia --------------------- --- 40 

Surcula __ _ ------------ --------- 40 

Dictyococcites bisectus _ 

scrippsae 

diegoana, Calyptraea __________ _ 

--- 25 

25 

--- 28 

23 

-- 46 

Diller, J. S., cited _____________________ _ 

Diplodonta 

parilis _ --------------------- 28, 46 

divaricata, Nucula __________________ 42 

diversilineata blakeleyensis, Turritella ____________ 30 

Drillia columbiana _________________________ 38, 39 

kennicotti ______ _____________ __ 39 

duplicata, Neverita ___________________________ 19 

Durham, J. W., cited _________ _____________ __ 24 

E 

Echinoderms ______ _ ---------- 17 

Echinoidea _______________ _ --------- 20 

Echinoids _ _ _____________ _ ---- 8, 20, 21 

Echinophoria 20,22 

rex Zone ___ _ 

Ecology 16 

edulis, Mytilus __ _____________ _____________ 44 

Eelgrass ___ _ _______________________ 21 

elephantinum, Dentalium _______________________ 41 

Ennucula _________ _ ---------- 22 

sp ---------------- --- 20 

Eocene, provincial correlation ____________________ 25 

Eocene-Oligocene boundary _ _ _________________ 24 

eocernua, Ocotea ____ _ ______________ ---------- 21 

eopelagicus, Coccolithus __ ----------------- 25 

Eosiphonalia _____________ 16, 19, 20,33 

californica _________________ ------- 33, 34 

oregonensis __________ 3, 11, 15, 16, 26, 33, pl. 4 

washingtonensis _____________ ____________ 33,34 

(Eosiphonalia) oregonensis, Siphonalia ____________ 33 

Eosolen ___ ___________ _________________ 16, 18, 52 

tEosolenl columbiana, Solena ______ ---------- 52 

eugenensis, Solena __ 14, 15, 16, 26, 28, 52, pl. 13 

Epitoniidae _____________________________ ------- 30 

Epitonium ___ _ 

keaseyensis ______ _ 

----------- 20, 22 

20 

fBoreoscalal condoni __________ _ 28 

28 

28 

condoni eugenense 

oregonensis ___ _ 

keaseyense _______ _____________ 31 

ergasticum, Dentalium ________________________ 41 

Ervilia____ __________________ 17, 18. 20, 50 

oregonensis ________________ 15. 16, 26, 50, pl. 16 

Eugene, Oreg __ _________________ 21, 25, 52 

Eugene Formation 1, 3, 5, 6, 7, 10, 23, 

25, 28, 35, 43, 44 

age ---------- 29 

fauna _________________________ 8. 21. 22,28 

lithology _ ______________ 21, 25 

Oreg 3, 10, 32, 33, 34, 41, 42, 43, 44, 45, 

46. 47. 48, 49, 50, 51, 52. 53, 54, 55 

eugenense, Epitonium IBoreoscala I condoni ________ 28 

Page 

eugenense-Continued. 

Parvicardium ______ _______________________ 28 

eugenensis, Modiolus ___________ ---------------- 28 

Solen _____________ _ ______________ 52 

Solena ---------------------------------- 21, 52 

(Eosolen) ________ 14, 15, 16, 26, 28, 52, pl. 13 

Spisula ---------------------------------- 28, 50 

eugenia, Tellina -------------------------------- 28 

Eurytellina ______________________________________ 50 

(Eurytellina), Tel/ina ___ ___________________ 17, 18 

aduncanasa, Tellina ____ 14, 15, 16, 26, 50, pl. 11 

Exilia __________________________________ 20, 22,23 

lincolnensis ________ _ _____________ 20,28 

F 

Fasciolariidae __ ___________ _ ____________ 36 

Fauna, Eugene Formation _____________ 23 

Gries Ranch Formation _______________ 6, 21, 23 

Holocene __________ _ ------- 17 

Keasey Formation ___________________ 19, 20, 23 

Pittsburg Bluff Formation ________ 2, 3, 11, 16, 17, 

19, 20, 22, 23 

Stepof Bay, Alaska ____________________________ 7 

Tunnel Point Sandstone______ _ ___ 22 

Faunas, Oligocene _____ _ _______________________ 2 

Pacific coast_________________ _ ____ 2, 9 

(Felanial usta, Mysia ____ _____________________ 46 

Felaniella ---------------------------- 17, 18, 20,46 

goodspeedi ________________________________ 46 

griesensis 47 

parilis _ ------------------------ 47 

serricata ___ -------------------------------- 46 

snavelyi ___________________ 46, 47 

(Felaniellal snavelyi ___ 14, 15, 16, 26. 46, pl. 10 

IFelaniel/a) snavelyi, Felaniella 14, 15, 16, 26, 

46, pl. 10 

IFerminoscalal becki, Acril/a___ _ ________ 28 

dickersoni, Acrilla _______ 28 

Ficus ____ __________ __ ________ __________ ______ 22 

modesto ____ ------------------------------- 28 

filosa, Lucina ________ _ 

Fimbria _______ _ 

Fish ____________ _ 

Fish scales _____ _ 

Fisher Formation ____________ _ 

fishii, Molopophorus ______ _ 

Fissidentalium _________________ _ 

IFissidentalium I. Dentalium ____ _ 

laneensis, Dentaliwn 

Fissurella 

45 

22 

17 

20 

------- 7 

-------- 28 

---- 41 

----- 18 

14, 15. 16, 26, 28, 

41. pl. 7 

--------------- 19 

Fitch, John, cited _____________________ _ 17 

Flabellum _____________ ---------------- 21 

hertleini ________ ___________ _____________ 20 

floridanus, Cyclicargolithus ______________________ 25 

Foraminifera _________ 5, 7, 8, 9, 20, 22 

Bastendorff Shale_ _ ______________ 22 

planktonic ________________ _ 

Refugian Stage __ _ 

stages ________ -------------

upper Refugian Stage 

zones -----------------------

Formations, Oligocene. California_ 

fornicata, Patella _______ _ 

--------- 9, 17, 25 

------------- 6 

9 

- 6 

------------ 31 

Fossil localities, U.S. Geological Survey, 

Pittsburg Bluff Formation ___________ 55 

Fossils, collection___________ ___________ 2, 14 

Dall identifications _ ______________ 3 

fish __ _____________ ____________ 17 

fragments __ ____________ _ ____________ 17, 18 

locality numbers __________________ -------- 2 

Pittsburg Bluff Formation _________ 7 

plant leaves _ --------- 8 

preparation _______ _ _____________ 2, 3 

San Lorenzo Formation _____________________ 3 

sea urchin ___________ _ --------- 5 

Fresno County, Calif __________ _ --- 6 

Fulgurofusus ________________ _ ------ 22 

sp ---- ------------ --------------- 20 

Fusinidae - 36 
Fusinus IPriscofusus) stewarti 

Fusus geniculus _____ _ 

G 

Page 

----------- 36 

36 

gabbi, Molopophorus ___________ 1, 2, 3, 5, 11, 14, 15, 

16, 23, 24, 26, 35, pl. 5 

Galvin Station, Lewis County, 

Wash ______________ 39, 40, 43, 44, 45,47 

Gastropoda________ _______________ _ ______ 29 

Gastropods _________ 11, 14, 15, 16, 17, 18, 19, 20, 21, 

22, 23, 26, 28 

Gaviota Formation ____________________________ 24 

fauna _________________ _______________ 8, 24 

Gemmula __________________________________ 20, 22 

bentsonae _____________ 28 

geniculus, Fusus ______________________________ 36 

gettysburgensis, Acila IAcila) ________ 43 

gigantea, Venus 

Globigerinids _ 

Glossaulax ____ _ 

<Glossaulax), Neuerita ___ _ 

48 

17 

--- 32 

18 

reclusiana, Neverita _______________ 19 

tlwmsonae, Neuerita ______ 11, 14, 15, 26, 32, pl. 2 

Glycymeris ______________ ____________ 21 

glycimeris, Mya_ _______________ 52 

goodspeedi, Felaneilla _ _ __________ 46 

Taras _______________________ 46 

Gorgonid coral ____________ _______________ 20 

gravida, Clat•ella ___ __________ _________________ 34 

Grecco Ranch House _____________________________ 4 

Gries Ranch Formation __ 4, 5, 6, 21, 23, 24, 25, 35, 43 

deposition ________________________________ 21 

equivalent _______ _ ------- 7 

fauna _______________ 6, 21, 23 

Oreg ------------- _____________ 36, 41,43 

Wash ________ 6, 31, 32, 33, 40, 41, 44, 51, 52 

Gries Ranch horizon 

griesensis, Felaniella 

Gyrineum _ 

H 

Habitats, mollusks ________ _ 

Haliotis 

haliotoidea, Helix ____________ _ 

----------- 5 

----- 47 

20, 22 

---- 17, 18, 19 

------------- 19 

33 

hannai, Cyclocardia ___ _________________________ 45 

hannibali, Cyclocardia 45 

Cyclocardia <Cyclocardia) 8, 11, 15, 16, 45, pl. 9 

Lucinoma ______________ ______________ 46 

hanniballi, Nucula ________________ 42 

haydoni, Planulina ______________ _____________ 8 

Helix haliotoidea 33 

Hemifusus washingtoniana __________________ 36 

<Here), Lucina ________________________________ 23 

hertleini, Flabellum______________ _____________ 20 

Opalia IDentiscalal ______ 11, 15, 16, 26, 30, pl. 3 

Suavodrillia ___________________________ 39, 40 

IHeteromacoma) uancouuerensis, Macoma _ 28 

Hiatellidae ____________________________________ 52 

History of investigation________ ______________ 1 

hodgei, Cibicides ________ ______________ 8 

hornii, Callista _______ _ 

hyperborea, Yoldia 

inquinata, Macoma 

Introd11ction 

lsocrinus _____ _ 

nehalemensis __ 

oregonensis__ 

lsthmolithus recuruus 

jamesae, Neverita 

Japan ___ _ 

Jones Beach 

josephinia, Neuerita 

,J 

----------- 49 

44 

28 

1 

----------- 20 

------ 20 

---------- 20 

------------ 25 

33 

8 

19 

32 

INDEX 

Page 

K 

Kalayoldia _____________ _ _____________ 44 

(Kalayoldia), Yoldia -------------------------- 17, 18 

cooperi, Yoldia _____________________________ 19 

oregona, Yoldia ________ 14, 15, 16, 26, 28, 44, pl. 9 

Keasey Formation ____________ 3, 5, 6, 7, 8, 10, 11, 19, 

21, 23, 24, 25 

age ---------- ________________________ 25 

coccoliths ____________ _ 25 

deposition __________________________________ 7 

fauna ______________________ 19, 20, 21, 22, 23,28 

mollusks -------------------------------- 28, 29 

northwestern Oregon ________________________ 23 

Oreg ---------------------- 10, 33, 41, 45, 47, 55 

Vernonia area ____________________ 19, 20, 21, 30 

volcanic ash ______________________________ 21 

Keasey Shale ______ _________________________ 1, 6 

Keasey Stage ________ _______ _ ______ 7, 9 

keaseyensis, Epitonium I _________________________ 20 

Epitonium <Boreos~ala) ______________________ 31 

Keenaea ________________________________________ 47 

IKeenaea ), Nemocardium ______________________ 17, 18 

lorenzanum, Nemocardium -14, 15, 16, 26, 47, pl. 10 

kennicotti, Drillia -------------------------------- 39 

kincaidi, Spirotropis __________ 11, 14, 15, 26, 39, pl. 7 

Turricula ---------------------------------- 39 

Turris _____________________________________ 39 

Kirker Formation, Calif __________________________ 43 

Kirker Sandstone____________ 8 

Kirker Tuff ____________________________ 4, 25, 28, 49 

Kleinpell, R. M., cited ____________________________ 24 

quoted_ _ ____________ 23 

Knefastia ____ ___________________________________ 22 

Kreyenhagen Formation ________________________ 9 

Kreyenhagen Shale ____________________________ 4, 6 

Calif------------------------------------ 44, 49 

kusiroensis, Mya (Arenomya) ____________________ 28 

L 

Lacia ---------------------------- _____________ 42 

laeuis, Pandora (Pandora) ________________________ 28 

ILamelliconcha) clarki, Pilar ______________________ 28 

laneensis, Dentalium __________________________ 9, 42 

Dentalium (Fissidentalium) ________ 14, 15, 16, 26, 

28,41' pl. 7 

Ieana, Anatina ---------------------------------- 53 

Leda acala -------------------------------------- 43 

lincolnensis ________________________________ 43 

oregona ------------------------------------ 44 

washingtonensis _________________________ 43 

Leionucula ____________________ _ 42 

ILeionucula), Nucula ________________________ 17, 18 

nuculana, Nucula ___________________________ 42 

uokesi, Nucula __ 14, 15, 16, 26, 42, pl. 8 

lignaria, Bulla _______________ --------------~--- 41 

Lima ________ _ -------- 20, 22 

Lincoln Creek beds _____________ _ ------ 4 

Lincoln Creek Formation ____________________ 25, 45 

Wash ____ 8, 10, 24, 28, 29, 30, 31, 32, 33, 34, 35, 

36, 38, 39, 40, 41, 43, 44, 45, 47, 48, 49, 53, 55 

Lincoln Formation ____ _ ________ 4, 35, 38 

Lincoln horizon __________ _ ___________ 4, 5 

Lincoln [Lincoln Creek] Formation __ 3, 5, 6, 8, 23, 24 

Lincoln Stage_____________ __________________ 7, 9 

lincolnensis, Exilia 20, 28 

Leda ______ _ __ 43 

Molopophorus _ _____ _ _ ___ 35 

Natica _______ _ - 32 

Nuculana ______ _______________ 4 

Perse _________ _ ______________ 28,37 

Polinices _________________________ 32 

washingtonensis ________________________ 32 

(Polinices) washingtonensis ______________ 32 

Solena ____________________________________ 52 

Tellina (Moerella) ________ _ 28 

Liracassis_______________________ _ ___ 14, 23 

Litorhadia _ _ ________ _ _ ___ _ ___ 16, 19, 20,43 

washingtonensis ____ 8, 14, 15, 16, 21, 26, 43, pl. 9 

Long Island, N.Y ___________ _________________ 19 

63 

Lorenzana, Solena --------------------------

Page 

52 

lorenzanum, Cardium---------------------------- 47 

Cardium cooperii _________________ 47 

Nemocardium ______________________ 8, 19, 21, 47 

<Keenaea) __________ 14, 15, 16, 26, 47, pl. 10 

Lorenzian Stage ________________________________ 9 

Loxocardium _______________ 21, 23 

Lucina columbiana _____________________________ 46 

filosa __ ---- ____ -- _ _ _ _ __ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ 45 

(Here) __ _ ----------- 23 

Lucinidae _____________________________________ 45 

Lucinoma ---------------------------- 17, 19, 20,45 

acutilineata ____________________________ 28, 46 

annulata _ ______________ _ ___________ 46 

columbiana __________ 8, 14, 15, 16, 26, 45, pl. 10 

hannibali ____________ 46 

M 

Macoma_ _ _____________________ 20, 22,23 

inquinata _________________________________ 28 

(Heteromacoma) uancouuerensis ______________ 28 

Macrocallista ___________________________ 48, pl. 17 

pittsburgensis _________ _ ________ 2, 9, 48 

community______ _______________________ 9 

IMacrocallista), Callista __________________________ 17 

nimbosa, Callista ____ _ _______________ 48 

pittsburgensis, Callista __________ 3, 15, 16, 19, 26, 

48, pl. 12 

Macrouridae ___________ 17 

Mactra oualis _____________ ______ _______ 49 

pittsburgensis __ ______ _______ _ ______ 6 

salida ____________________________________ 49 

Mactracea __ _________________ 50 

Mactridae ______________________________________ 49 

Mactromeris ____________________________________ 49 

IMactromeris), Spisula ____________________ 17, 18,50 

pittsburgensis, Spisula ____________ 14, 15, 16, 26, 

49, pl. 14 

ueneriformis, Spisula_____ 11, 15, 16, 26, 

50, pl. 14 

Malletia __ _ _________ 20 

mamillaria, Natica _____________________________ 32 

Margaritan Stage_____ __________ 9 

Marrowstone Shale, Wash ____________________ 34, 48 

Martesia ________________________________________ 22 

sp -------------------- -------------- 28 

maximus, Brisaster __________________ 20 

Megafauna! zones, Tertiary ______________________ 24 

Meretrix ICallista) pittsburgensis __________________ 48 

merriama, Nuculana ---------------------------- 22 

Mesodesmatidae _______________________ 50 

minima, Acila ITrur.cacila) nehalemensis __________ 28 

Minormalletia ---------------------------------- 22 

sp _ _ __ _ _ _ _ _ _ __ __ _ _ __ __ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ __ _ _ 20 

Miocene, provincial correlation __________________ 25 

Mist, Oreg _________________________ 2, 5, 11, 20, 21 

Mitra ________________________________________ 20, 22 

modesta, Ficus ---------------------------------- 28 

Modiolus---------------------- ________ 22 

eugenensis ---------------------- ___________ 28 

IMoerellal lincolnensis, Tellina ____________________ 28 

Mollusca ______________________________________ 29 

Mollusks, Alaska_______________________________ 8 

Alsea Formation ____________________________ 23 

Asiatic origin______________________________ 8 

Bastendorff Shale_____________ 22 

Calif -------------------------------------- 6, 8 

faunal zones ______________________ 14 

fragments _____________________________ 17, 18 

habitats _____________ _ ______________ 18 

infaunal community _______________________ 17 

Keasey Formation ________________________ 28, 29 

Lincoln Stage _______________ 9 

Newport area _________________ 23 

Oreg ___________ _________________________ 8 

Pacific Coast ______________________________ 9, 23 

Pittsburg Bluff Formation ____ 2, 7, 11, 14, 16, 19, 

20, 22, 25, 28 

distribution ______ ______ ______ 25 

post-late Eocene ____________________________ 9 
64 

Page 

Mollusks-Continued. 

stages --··--------- 9 

taxonomy _______ _ ------------- 2 

Tertiary, Calif ___ _ ------------------------- 6 

Tertiary formations__________________________ 6 

Tunnel Point Sandstone___________ 22 

Twin River Formation ______________________ 8 

zones 

Molopophorus ___________ 16, 19, 20, 35, pl. 17 

biplicatus __ ______________ _ _______ 35 

quadranodosum ______________________ ___ 35 

dalli __ ___________ _ ____ 6, 8. 24, 28, 35 

fishii _____________________________________ 28 

gabbi __ 1, 2, 3, 5, 11, 14, 15, 16, 

23, 24, 26, 35, pl. 5 

Zone ____ 2, 6, 7, 24, 34, 35, 37 

of Durham ______________ __________ ____ 7 

lincolnensis ______________________________ 35 

Zone __ ____________________ _ ______ 3, 4, 5 

stephensoni Zone _________________________ 6, 37 

IMolopophorus) striata, Bullia _______ 35 

Monterey Bay. Calif __ ______________ 14 

Montereyan Stage ___ 9 

Montesano horizon _____ _ 

Moody Shale Member, 

Toledo Formation ____ _ 

morchi, Trophon _______ _ 

Muricacea 

Mya ________ _ 

glycimeris ___________ _ 

nitens _______________________ _ 

4 

7 

-- 38 

----- 16 

IArenomyal kusiroensis __________ _ 

------ 22, 54 

52 

50 

28 

Myrica 21 sp _____________ _ 

Myrteinae ________________________ _ ----- 45 

Mysia !Felania) usta __________ _ _________ 46 

Mytilidae ____ ___ _ ____ _ _ 44 

Mytilus ____________________________ 17, 18, 19, 20. 44 

decussatus _________________________________ 45 

edulis ____ ____ ____ ____ _ ___________ 44 

snohomishensis _______________ 14, 15, 16, 28,44 

Natica brunnea _______ _ 

clausa ___ _ 

N 

32 

31 

lincolnensis -------------------------------- 32 

mamillaria ___________ ____________________ 32 

tectula _ ___________ __ _________ 31 

washingtonensis ______________ 32 

weaueri __ 31 

(Natica I sp ________ ___________ 28 

INatica I sp., Natica ____________________________ 28 

Naticidae ______________________________________ 31 

Naticids __ ----------------------------------- pl. 17 

Naticinae __________________________ 31 

Nautilidae _____________________ _ _______ 54 

Nautilites angustatus _________ _ 54 

Nautilus angustatus ________________ 54 

Nehalem River, Oreg __________ 2, 3, 5, 11, 37, 50, 51 

Nehalem River Highway, 

near Pittsburg, Oreg ________________ 7 

nehalemensis. Acila ______ _ ______________ 24 

Acila iTruncacila I ______________ 20, 21, 23, 28, 43 

Isocrinus ___ _____________ _ _____ 20 

minima, Acila iTruncacila) __ _ ______ 28 

Neilo oregona__________ _ _________________ 44 

Nekewis __________________________________ 20, 22 

Nemocardium __ _ _________________ 22, 47 

lorenzanum ------------------------ 8, 19, 21, 47 

samarangae -------------------------------- 47 

iKeenaea) ______________ ________________ 17, 18 

lorenzanum ________ 14, 15, 16, 26, 47. pl. 10 

Neptunea ______ _ _________ · 22 

Neptuneidae __________________________________ 33 

Nestucca Formation __ 

Neuerita 

duplicata ______ _ 

jamesae 

josephinia 

------------------------ 23 

--- 16, 18, 20,32 

---------------- ------ 19 

------ 33 

------ 32 

reclusiana ____________ 32 

thomsonae ______________________ 8, 9, 21, 28, 32 

INDEX 

Page 

N everita-Continued. 

iGlossaulax) ________ _ 17, 18 

reclusiana ____________________________ 19 

thomsonae _________ 11, 14, 15, 26, 32, pl. 2 

Newport, Oreg _____ _ _____________________ 25, 28 

nimbosa, Callista ______________________________ 49 

Callista (Macrocallista) _____________________ 48 

Venus __________ ________________ --------- 48 

nitens, Mya______ _ _________________________ 50 

Norbisrath, Hans, quoted ____________________ _ 

Notorhynchus _________________________________ 17 

Nucula ____________________________________ 20,42 

albensis ___________________________________ 42 

castrensis __________________________________ 42 

decisa ____________________ _ ________ 42 

diuaricata 

hanniballi __ 

42 

---------------- 42 

vokesi _____________________________________ 42 

(Acila) decisa ____________ 42 

shumardi _____________________________ 42 

iLeionuculal 17, 18 

nuculana _ ------------------------- ---- 42 

vokesi _______________ 14, 15, 16, 26, 42, pl. 8 

Nuculana ___________________________________ 16, 22 

lincolnensis ___ _______________ ____________ 4 

merriama __ ------- 22 

oregona _________________________ 44 

washingtonensis ____________________ 9, 20, 28, 43 

community__________ ___________ _______ 9 

nuculana. Nucula (Leionucula) _________________ 42 

Nuculanidae ____________________________________ 43 

nuculeus, Area _________________________________ 42 

Nuculidae _______________ ___________ _ ________ 42 

Nye Shale __ _____________ 5 

0 

oamaruensis, Chiasmolithus _ _ ____ 25 

obliquum. Sinum __________ 11, 15, 16, 19, 28, 33, pl. 1 

obliquus, Solen __________________________________ 52 

Ocotea eocernua _______ ------------------------ 21 

Odontaspis _____________________________________ 17 

Odostomia __ _ __________________ 16, 17, 20,40 

winlockiana ____________ 11, 15, 16, 26, 40, pl. 3 

(0dostomial winlockiana ____________________ 40 

iOdostomial winklockiana, Odostomia ____________ 40 

Olequahia ---------------------------------- 20, 22 

schencki ___________ _ ________________ 28 

Oligocene, climate ______________________ 4, 6, 8, 9, 19 

faunal horizons_______ ______________________ 5 

formations _____ _ 

marine rocks_____ _ _______________ _ 

middle, U.S. Geological Survey 

fossil localities __ _ -------- 55 

provincial correlation _ _ __________ 25 

Oligocene faunas, Alaska ________________________ 8 

Oreg _________ ____________ 19 

summary _______________________________ 23 

Pacific Coast __ _________________ 2 

Oligocene sea ____________________ 7, 14, 19, 21 

Oligocene sediments, deposition ________________ 7, 25 

Pacific Northwest_ _________________________ 25 

Oligocene-Miocene boundary ___________________ 24 

Oliuella ________________ 19 

olympi£ensis, Perse ----- 24, 37 

quimpersensis. Perse ___________ 6, 24, 37 

Opalia ______________________ 16, 20,30 

colimana ___________________________________ 31 

IDentiscala) ___________________ ___________ 17, 18 

hertleini __ 11, 15, 16, 26, 30, pl. 3 

Operculina sp ______________ _ _____ 20 

Opertochasma 

turnerae 

Ophiuroidea ___ _ 

---------------------------- 22 

----- 28 

------- 20 

Oregon, Oligocene faunas ______________________ 19 

Oligocene faunas, summary __________________ 23 

Oregon City, Oreg _____________________________ 44 

oregona, Leda __ -------------------- 44 

Neilo ________ _ ------------ --------------- 44 

Nuculana __ ____________ _ ________________ 44 

Yoldia ____________________________________ 44 

oregona-Continued. 

(Cnestrium I 

(Kalayoldia) 

(Portlandia I 

Page 

----------- 44 

14, 15, 16, 26, 28, 

44, pl. 9 

---------- 44 

oregonensis, Cryptonatica ______________ 31 

Eosiphonalia _________ 3, 11, 15, 16, 26, 33, pl. 4 

Epitonium rBoreoscala) condoni _____________ 28 

Ervilia __________ 15, 16, 26, 50, pl. 16 

Isocrinus _____ ____________ 20 

Siphonalia _______________ 33 

IEosiphonalia I',-_______ 33 

Strepsidura _ _____________ 33 

Turritella ______________________________ 29, 30 

Ostrea --------------------------- 16, 40 

Otoliths ____ _ 17 

oualis, Mactra ------------ 49 

p 

Pachydesma _____ 22 

packardi, Plectofrondicularia ____________________ 20 

Spisula _____ ------------------------------ 22 

Pandora ________________________________________ 22 

(Pandora I laevis ---------------------------- 28 

!Pandora) laevis, Pandora ________________________ 28 

Pan ope __________________________________________ 52 

aldrovandi __________________________________ 52 

ramonensis _________________ 53 

snohomishensis ------------------------------ 52 

Panopea _________________________ 17, 18, 19, 20,52 

abrupta ___________________________________ 53 

ramonensis 9, 14, 15, 16, 26, 53, pl. 15 

snohomishensis __________ 14, 15, 16, 26, 52, pl. 15 

iPanopea) ramonensis _______________________ 28 

IPanopeal ramonensis. Panopea __________________ 28 

Parasyrinx _____________________________________ 39 

parilis, Diplodonta -------------------------- 28, 46 

Felaniella ---------------------------------- 47 

Paruicardium ___________________________________ 22 

eugenense ---------------------------------- 28 

paruuum, Acteon __________________ 28, 40, 41 

Patella fornicata __ ----------------------------- 31 

Pebble Creek------------------------------------ 6 Pecten ____________________________________ 16, 22, 40 

pelagicus, Coccolithus _________________ 25 

Pelecypoda _____________________________ 42 

Pelecypods _____________ 11, 14, 15, 16, 17, 18, 19, 20, 

21, 22, 23, 26, 28 

Periplomatidae __________________________________ 53 

Perse __ _ _____________ 16, 19, 20, 36, pl. 17 

corrugatum _____ _ ___________ 36 

lincolnensis _______________________ 28, 37 

olympicensis ___________________________ 24, 37 

quimpersensis __________ 6, 24, 37 

pittsburgensis _________ 6, 11, 14, 15. 16, 24, 26, 

36, 37, pl. 6 

vernoniensis _________ 11, 14, 15, 26, 37, pl. 6 

perspectiuus, Trochus ___ -----------------------, 29 

Phacoides columbianum __ ----------------------- 45 

Phanerolepida__ _ ___________________ 20, 21 

Pholas ____ --------------------------------- ___ 22 

pileum, Crepidula ____________ 11, 15, 16, 26, 31, pl. 1 

Crepidula iSpirocrypta) _____________________ 31 

Crypta ISpirocrypta) _ _ ____________ 31 

Pitar ____________ _ 

dalli _____________ _ 

17, 18, 20, 22,47 

------------- 47 

(Lamelliconchal clarki__________ _ ___ 28 

IPitar) dalli ____________ 15, 16, 26, 28, 47, pl. 12 

sp -------------------------------------- 28 

(Pitar) dalli, Pitar __________ 15, 16, 26, 28, 47, pl. 12 

sp., Pitar ___________________________________ 28 

Pitaria dalli ___________________________________ 47 

Pitarinae ___ _ _____________________ 47, 49 

Pittsburg, Oreg. __________________ 2, 5, 11, 25, 49. 50 

Pittsburg Bluff, Oreg ____ __________________ ____ 3 

Pittsburg Bluff Formation_______ 1, 4, 5, 6, 10, 23, 24, 

41, 50 

age ________________________________ 2, 23, 25, 29 

coal _____ _ ________ 7, 18, 19 

correlation ________________ 2, 4, 5, 6, 7, 10, 24,25 
Page 

Pittsburg Bluff Formation-Continued. 

deposition __________________________ 19 

ecology____________ _ ___________________ 16 

equivalents ____________________ ·--- 5, 28 

fauna_ 2, 3, 6, 7, 8, 11, 16, 17, 19, 20, 21, 

22, 41, 47, 50 

faunal zones -------------------------------- 14 

fossil localities __________________________ 10, 55 

fossil matrix __________________________ 17, 18 

geographic distribution ______________________ 10 

habitats ______________________________ 17, 18, 19 

lithology ______________________ 2, 3, 6, 7, 11,25 

lower member____________ ______________ 2, 6 

mollusks __________ 2, 3, 4, 6, 7, 8, 11, 14, 16, 17, 

19, 20, 22, 25, 28, 29 

distribution ___________________________ 25 

northwestern Oregon ____________________ 10.23 

Oligocene faunas, Oregon ____________________ 19 

Oreg ____________________________ 33, 34, 35,37 

shale ____________________________ _ 

species checklist ---------------------------- 14 

stratigraphic sections________________________ 2 

stratigraphy ________________________ 6, 7, 10, 19 

terrestrial beds------------------------------- 6 

thickness _________ 7, 11, 14, 19 

type area __________________________ 2, 5,11, 42 

type locality ___________ 2. 6, 7. 11, 21, 24, 54 

upper member __________ 2 

Vernonia area ____________ 19, 20, 30, 31, 33, 37, 

38, 43, 49, 51 

Pittsburg Bluff sandstone __ 

Pittsburg Bluffs-------------------------------- 1, 5 

pittsburgensis. Callista 1, 4, 5, 6, 8, 21, 23, 

28, 48,49 

Callista (Macrocallista) 3, 15, 16, 19, 26, 

48, pl. 12 

Cryptonatica ____________ 11, 14, 15, 26, 31, pl. 1 

Macrocallista __________________________ 2, 9, 48 

Mactra -------------------------------------- 6 

Meretrix (Callistal __________________________ 48 

Perse _________________ 6, 11, 14, 15, 16, 24, 26, 

36, 37, pl. 6 

Spisula __________________________ 5, 24, 28, 49 

Spisula IMactromerisl ____________ 14, 15, 16, 26, 

49, pl. 14 

Tellina ________ 5, 14, 15, 16, 21, 26, 28, 51, pl. 11 

Turritella ________________ 11, 15, 16, 26, 29, pl. 3 

vernoniensis, Perse _______ 11, 14, 15, 26, 37, pl. 6 

plagiaulax, Solen______________ 52 

Plantae __________ _ ___________ 20 

Planulina haydoni ___ ___ 8 

Plectofrondicularia packardi ______________________ 20 

<Plectosolenl townsendensis, Solen ________________ 51 

Pleito Formation ______________ 4 

plicatus, Turbo ---------------------------------- 40 

Polin ices________ _ ___ 16, 20, 22, 32 

albus -------------------------------------- 32 

lincolnensis -------------------------------- 32 

washingtonensis ___________ 8, 11, 14, 15, 21, 26, 

28, 32, pl. 1 

lincolnensis ----------------------------- 32 

sp ------------------------------------------ 20 

<Polinices) 17, 18 

washingtonensis lincolnensis 32 

(Polinicesl, Polinices ________ _____________ 17, 18 

washingtonensis lincolnensis, 

Polinices ---------------------------- 32 

Polinicinae ______________ 32 

Porter horizon _ 4 

Porter Shale ___ _ -------------------- 7 

porterensis, Crenella _____ 11, 15, 16, 19, 26, 45, pl. 12 

Dentalium ____ _ _________________________ 22 

Turritella -------------------------------- 29, 30 

Porterius __ _ _____________________ 20, 22 

(Portlandellal chehalisensis, Yoldia 20 

!Portlandial oregona, Yoldia ______________________ 44 

Poul Creek Formation ______________________ 5, 8, 25 

Alaska ______________ 8, 28, 34, 36, 43, 44, 45, 46, 

47, 48, 49, 50, 51, 52, 53, 54 

mollusks 9 

Priscofusus ----------- 16, 19, 20,36 

INDEX 

Page 

Prisco{ usus-Continued. 

chehalisensis ______________ _ 36 

stewarti __________________ 11, 15, 16, 26, 36, pl. 3 

IPriscofususl stewarti, Fusinus ________________ 36 

Pristiophorus ____________________________________ 17 

Propeamussium ------------------------------ 21, 22 

sp _________________________________________ 20 

Protocardiinae _________________________________ 47 

Pseudocardium ___ ------------------------------ 22 

sp _ _ __ __ _ _ _ _ ___ _ __ _ _ _ _ _ _ __ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ 28 

Psychosyrinx ___________________________________ 39 

Puncturella __________ ____________________________ 21 

punicea, Tellina __ ----------------------------- 50 

Purpose and scope ______________________________ 2 

Pyramidellidae _________________________________ 40 

Q 

quadranodosum, Molopophorus biplicatus ________ 35 

Quercus consimilis ________________ 21 

Quimper Sandstone________ _ ____ 7, 25, 28 

Wash ____________ 32, 34, 35, 41, 44, 50, 51, 52, 54 

quirnpersensis, Perse olympicensis 6, 24, 37 

R 

radiata, Tellina __ 50 

Raja ___________ _ ------------------------------- 17 

ramonensis, Panope __ 53 

Panopea ______________ 9, 14, 15, 16, 26, 53, pl. 15 

iPanopea) ------------------------------ 28 

Rat tails_______________ _ ________________ 17 

Ray teeth _ ------------------------------------ 17 

reclusiana, Neverita ___________________ 32 

Neverita (Glossaulax) ________________________ 19 

recurvus, Isthmolithus ---------------------------- 25 

Refugian Stage __________________ 1, 5, 6, 7, 9, 23, 24 

definition ------------------------------ ____ 24 

foraminifers -------------------------------- 6 

Oreg _______________________________________ 23 

type locality _____________________________ 23, 24 

Wash __________________________________ 23 

Reports dealing with Oligocene Formations 

and fossils, annotated chronology 3 

Restoration Point, Wash ________________________ 36 

Restoration Point horizon ______________________ __ 5 

Rices Mudstone Member, 

San Lorenzo Formation _______ 8, 44, 47 

rosaceus, Solen------------------------------- __ 52 

s 

Salenia ____________________________________ 20, 21 

schencki ____________________________________ 20 

samarangae, Nemocardium ______________________ 4 7 

San Emigdio Canyon, Calif __________ 5 

San Emigdio Formation _____________ 4, 5, 6, 28, 32 

Calif________________________________________ 43 

mollusks________________________________ 8, 25 

San Emigdio Mountains, Calif _________________ 5, 9 

San Lorenzo Formation _____________________ 3, 8, 28 

Calif -------------------------------- 33, 36, 54 

deposition ______ _____________________ 9 

foraminifera ________ _______________________ 8 

members____________________________ _______ 8 

mollusks_______ _ ___________________ 8, 25 

Mount Diablo area __________________________ 4 

San Lorenzo Group ____________________________ 4, 6 

San Lorenzo Series ____________ 4 

San Ramon Formation ____________________ 5, 7, 8, 36 

San Ramon horizori _·___ ____________________ 5 

San Ramon Sandstone, Calif _____________ 35, 36. 53 

Santa Ynez Mountains, Santa 

Barbara County, Calif ______________ 23 

Santa Ynez Range, Calif 24 

Seal aria australis_____________________________ 30 

Scaphander _________ 17, 18, 22, 41 

stewarti _______________ 11, 14, 15, 19, 20, 26, 28, 

41' pl. 7 

washingtonensis ___________________________ 41 

Scaphandridae -- 41 

65 

Page 

Scaphopod_________ 14, 15, 16, 17, 18, 26, 28 

Scaphopoda ___________________________________ 41 

Scappoose, Oreg ________________________________ 7 

Scappoose Formation ________________ 6, 7, 10, 11, 29 

Schenck, H. G., cited ____________________________ 24 

quoted _____________________________________ 23 

schencki, Olequahia ------------------------------ 28 

Salenia ------------------------------ 20 

Thracia _____ _ ------------------------ 54 

scopulosum, Sinum _____________________________ 33 

scrippsae, Dictyococcites _________________________ 25 

Seastars ________________________________________ 21 

Semele_______ ________________________ 22 

willamettensis ------------------------------ 28 

semiasperum, Cardium _________________________ 47 

sericata, Taras __ _____________________________ 46 

serricata, Felaniella ------------------------------ 46 

Shark teeth ------------------------------------ 17 

shumardi, Acila ________________ 1, 2, 3, 4, 5, 6, 8, 21, 

24, 28, 42, 43 

Acila ITruncacila) ___ 2, 14, 15, 16, 19, 21, 23, 

24, 26, 28, 42' pl. 8 

Nucula (Acila) ------------------------------ 42 

sicarius. Solen ------------------------------ 28, 51 

Siltstone, Newport area, Oreg ____________________ 9 

Siltstone of Alsea________________________________ 9 

Sininae ________________ _ __________ 33 

Sinum _________________________ 16, 17, 18, 33 

obliquum ___________ 11, 15, 16, 19, 28, 33, pl. 1 

scopulosum __________________________________ 33 

Siphonalia __ ----------------------------------- 33 

oregonensis_ ________ _______________________ 33 

(Eosiphonalia) oregonensis_______________ 33 

snavelyi. Felaniella _______ _ ________ 46,47 

Felaniella tFelaniella) _ 14, 15, 16, 26, 46, pl. 10 

snohomishensis, Mytilus ______ 14, 15, 16, 28, 44 

Panope _ _______________________ 52 

Panopea ________________ 14, 15, 16, 26, 52, pl. 15 

Solemya -------------------------------- 20, 21,22 

(Acharax) willapaensis _________________ 20 

Solen --------------------------- ____ 17, 18, 20,51 

conradi ___________________________________ 52 

eugenensis _________________________________ 52 

obliquus ___ _ _______________ 52 

plagiaulax -------------------------- ___ 52 

rosaceus _ --------------------------- 52 

sicarius___________ _ ________________ 28, 51 

townsendensis _________ 14, 15, 16, 26, 51, pl. 13 

vagina_ ------------------------------------ 51 

iPlectosolen 1 townsendensis _____________ 51 

Solena ------------------------------------ 20,52 

clarki _____________ 52 

eugenensis 

lincolnensis 

---------------- --- 21, 52 

-------------------------------- 52 

Iorenzana ---------------------------------- 52 

iEosolen) columbiana _______________________ 52 

eugenensis ________________ 14, 15, 16, 26, 28, 

52, pl. 13 

Solenidae ________________________ 51 

salida, Mactra ---------------------------------- 49 

solidissima, Spisula ____________ _________________ 19 

solidum. Cardium ------------------------------ 49 

Sooke Formation 4, 5 

Vancouver Island, B.C ______________________ 46 

sookensis, Calyptraea ____________________________ 28 

(Spirocrypta) pileum. Crepidula __________________ 31 

pileum. Crypta ------------------------------- 31 

Spirotropis ____________________ 17, 18, 20, 21, 22,39 

carinata ---------------------------- _______ 39 

kincaidi __________________ 11, 14, 15, 26, 39, pl. 7 

washingtonensis ____________________________ 39 

iSpirotropis) winlockensis ____________________ 40 

iSpirotropis) winlockensis. Spirotropis ____________ 40 

Spisula ____________________ 18, 19, 20, 49 

eugenensis _______________________ 28, 50 

packardi _ _ _______________________ 22 

pittsburgensis _____________________ 5, 24, 28, 49 

solidissima ____________ ____ __ ______ __ ________ 19 

veneriformis ______________________________ 50 

(Mactromeris I _______________________ 17, 18, 50 

pittsburgensis ______ 14, 15, 16, 26, 49, pl. 14 
66 

Page 

Spisula-Continued. 

veneriformis 11, 15, 16, 26, 50, pl. 14 

Squalus __________ ___________________ 17 

Squatina _____________________ _ ________ 17 

Stepof Bay, Alaska __ 

Stepovak Formation____ 8, 25, 28. 43, 47, 53. 54 

Stepovak Series -------------------------------- 8 

stewarti, Fusinus !Priscofusus) ___________ 36 

Prisocofusus ______________ 11, 15, 16, 26, 36, pl. 3 

Scaphander _______ 11, 14, 15, 19, 20, 26, 28 

41, pl. 7 

Strata, Nehalem River _ ________________________ 3 

Stratigraphic sections, Pittsburg 

Bluff Formation 

Strepsidura oregonensis --------------------- 33 

washingtonensis ________________ 33 

striata, Bullia !Molopophorusl ____________________ 35 

Suavodrillia ______________ _________________ 20,39 

dickersoni _________ _ ____________ 40 

hertleini ______________ _________________ 39, 40 

winlockensis _ 

subtenta, Cyclocardia __ 

Surcula dickersoni 

Systematic descriptions 

Taranis 

T 

columbiana _____________ _ 

Taras goodspeedi 

11, 14. 15, 26, 40, pl. 7 

-------------- 45 

40 

------------------ 29 

17, 18, 20. 38 

11, 14, 15, 26, 38, pl. 7 

46 

sericata _______ ____ 46 

Tectonatica____________ 31 

tectula, Natica ____ 31 

Tegula _________________ 19 

Tejon Formation __________________________ 5, 23, 31 

Calif _________________ 31, 33, 35 

Tejon Pass, Calif ___ 31 

Tejon Stage _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 5 

Tellina _ _ _______________________ 20, 22, 50 

aduncanasa _______ 8, 21, 28, 50 

eugenia ------------------------------------ 28 

pittsburgensis ______________ 5. 14, 15, 16, 21, 26, 

28,51' pl. 11 

punicea ____________________________ 50 

radiata_____________ _ ___________ c __ 50 

sp __ ______________________ 20, 28 

!Euryte!lina) _____________ _ ____ 17, 18 

aduncanasa ________ 14, 15, 16, 26, 50, pl. 11 

(Moerella llincolnensis __________________ 28 

Tellinidae ______ _ ______________________ 50 

Tellininae _______________ _ _______________ 50 

Temblor Formation _______________________ 9, 25, 28 

Calif _________________________ 33, 34, 39, 42, 53 

Temblor Range, Calif______________ 24 

Temblorian Stage _______________________________ 9 

tenuissima, Yoldia ------------------------------ 44 

terebra, Turbo _________________________________ 29 

Thesbia columbiana__ ___________________ 38 

thomsonae, Neverita _________________ 8, 9, 21, 28, 32 

Neue rita !Glossaulax I ___ 11, 14, 15, 26, 32, pl. 2 

Thracia _______________ _ ___ 17, 18, 20, 22,54 

condonz· _____________________________ 21, 28, 54 

corbuloides _ _ _________________________ 54 

schencki ________ _ ___________________ 54 

trapezoides _________________________________ 54 

(Thracia I condoni ___ ____ 14, 15, 16, 26, 54, pl. 16 

(Thracia I condoni, Thracia 14, 15, 16, 26, 54, pl. 16 

Thraciidae __________________ 54 

Thuja sp __________________ _ __________ 21 

Thyasira _ ------------------------------ 20, 21, 22 

Tindaria ____________________ 20. 22 

Toledo Formation _____________________________ 7, 9 

Moody Shale Member_____ __________________ 7 

tornatilis. Voluta ____ _ ______ 40 

townsendensis, Solen 

Solen (Plectosolen I 

14, 15, 16, 26, 51' pl. 13 

---------------- 51 

trapezoides, Thracia _____________________________ 54 

INDEX 

Page 

Trochid, unidentified ___________________ 15, 29, pl. 1 

Trochidae ___________ _ ______________ 29 

Trochus perspectivus _ _ ______ 29 

Trophon morchi _____________________________ 38 

Truncacila ---------------------------------- 19,42 

(Trzmcacila I, Acila ______________ 17, 18, 22, 43 

nehalemensis, Acila ____________ 20, 21, 23, 28,43 

minima, Acila _________________ 28 

shumardi. Acila ______ 2, 14, 15, 16, 19, 21, 23, 24, 

26, 28, 42, pl. 8 

tumens, Venus ----------------------------- 47 

Tumey Formation ______________________ 7, 8, 25,28 

Calif ___ _ _________ 43, 44, 48, 51 

Tumey Sandstone_________________ ______________ 6 

Tunnel Point, Oreg _ ___________________________ 3 

Tunnel Point beds 

Tunnel Point Formation ________________ 5, 6, 23, 24 

Tunnel Point Sandstone ______________ 1, 5, 6, 22, 44 

mollusks ____________________________ 22, 25, 28 

southwestern Oreg ____ 23, 32, 34, 36, 39, 43, 

Turbo crenata 

plicatus _ 

terebra __ 

46, 48, 49, 50, 51, 52 

30 

40 

----------------- 29 

Turcicula _______________________________ 20, 21, 22 

columbiana __________________________________ 29 

turnerae. Opertochasma __________________________ 28 

turneri, Cylichnina _________________ 22, 28 

Turricula kincaidi ------------------------------ 39 

Turriculinae ___________________________________ 37 

Turridae ________________________________________ 37 

Turrinae ________________________________________ 38 

Turris kincaidi __________________________________ 39 

Turritella ________ 14, 16, 17, 18, 22,29 

diuersilineata blakeleyensis _________________ 30 

olympicensis Zone _______________________ 6, 34 

oregonensis ___________ _ ______ 29, 30 

pittsburgensis ____________ 11, 15, 16, 26, 29, pl. 3 

porterensis ____ _ __________________ 29, 30 

Zone ___________________________ 3, 4, 6, 34 

uuasana _____ ___________ _ __ 29, 30 

uariata Iorenzana Zone ___________ 24 

Zone _____________________________ 6, 23, 24 

wheatlandensis _____ _ ________ 30 

Turritellidae __ _ _______ 29 

Twin River Formation ________________________ 7, 10 

Wash____________ 10, 45 

Two Bar Shale Member, 

San Lorenzo Formation 

u 

Umpquaia ___ _ ____________________________ 34 

ungana, Crepidula ------------------------------ 28 

Ungulinidae ________ _ ___ 46 

Ushikubitoga Formation ________________________ 8 

Japan ___ 45, 46 

usta, Mysia (Felania I ____________ 46 

uvasana, Turritella ____ 29, 30 

Uuigerina cocoaensis ----------- 8 

v 

vagina. Solen ____ _____________________________ 51 

Vancouver Island ____________________ 4, 5 

uancouuerensis, Macoma (Heteromacoma ) __________ 28 

Vaqueros Sandstone ____________________________ 8 

Vaquerosian Stage 9 

Veneridae ___________________________________ 47 

veneriformis, Spisula ___________ 50 

Spisula !Mactromerisl ____ 11, 15, 16, 26, 50. pl. 14 

Venus chione__ ______________________ _ __ 48 

gigantea _________ _ ____________________ 48 

nimbosa ------------------------------ 48 

tumens ____ ______________ 4 7 

Vernonia. Oreg _________________________ 19, 25, 51 

vernoniensis, Perse 

Page 

uernoniensis-Continued. 

pittsburgensis _ 11, 14, 15, 26, 37, pl. 6 

Vertebrata _____________________________________ 20 

Vicksburg Group _ ------------------------------ 4 

Vokes, H. E., cited _________________________ 2, 7, 14 

vokesi, Bruclarkia ________________________________ 28 

N ucula _ _ _ _ _ _ __ _ _ _ __ _ ___ __ _ __ ___ _ __ ___ __ _ _ _ _ _ 42 

(Leionuculal ____ _____ 14, 15, 16, 26, 42, pl. 8 

Voluta tornatilis ____________ 40 

w 

Wahkiakum horizon ____________________________ 4 

wardi, Aforia ________ --------------------------- 38 

Aforia clallamensis ______________________ 16, 37 

Washington County, Oreg., 

stratigraphic section _______________ 2 

washingtonensis. Crenella ____________________ 45 

Eosiphonalia ____________________________ 33, 34 

Leda __ -------------------------------- ____ 43 

Litorhadia _________________ 8, 14, 15, 16, 21, 26, 

43, pl. 9 

Natica _ ------------------------- 32 

Nuculana ____________________ 9, 20, 28, 43 

Polinices _______________ 8, 11, 14, 15, 21, 26, 28 

32, pl. 1 

Scaphander -------------------------------- 41 

Spirotropis ---------------------------------- 39 

Strepsidura ------------ 33 

lincolnensis, Polinices ____________ 32 

Polinices !Polin ices)---------------------- 32 

washingtoniana, Hemifusus _ -------------------- 36 

Warren, W. C., quoted __________________ 2 

Weaver, D. W., cited _________ ___________ 24 

weaueri, Natica ___________________________ 31 

Welton, B. J., quoted ___________________________ 17 

Wheatland Formation ______________________ 6, 28, 30 

Calif -------------------------------- 28, 30, 32 

wheatlandensis, Turritella ________________________ 30 

Whitneyella ------------------------------------ 36 

Willamette Valley, Oreg ________________________ 28 

willamettensis, Semele __________________________ 28 

willapaensis, Solemya (Acharax I------------------ 20 

Wilson's Bluff, Oreg _____________________ _ 

winlockensis, Spirotropis (Spirotropis) 40 

Suavodrillia ______________ 11, 14, 15, 26, 40, pl. 7 

winlockiana, Odostomia ______ 11, 15, 16, 26, 40, pl. 3 

Odostomia (Qdostomia I ______________________ 40 

Worms, polychaete _____________________________ 40 

Wygal Sandstone Member __________________ 9, 25, 28 

Calif ________________________________ 33, 42, 53 

y 

Yakataga Formation ----------------------------

Yaquina Formation ________________________ 1, 5, 23 

Yoldia ---------------------------- 18, 19, 20, 22, 44 

arctica ____________________________________ 44 

cooperii ------------------------------------ 44 

hyperborea _________________________ 44 

oregona ------------------------------------ 44 

tenuissima ---------------------------------- 44 

(Cnestrium I oregona ________________________ 44 

(Kalayoldia I ____________________________ 17, 18 

cooperi ---------------------------------- 19 

oregona __________________ 14. 15, 16, 26, 28, 

44, pl. 9 

(Portlandella I chehalisensis __________________ 20 

!Portlandia I oregona _______________________ 44 

strigata Zone____________________ 4 

z 

Zemorrian Stage ____________________ 5, 9, 23, 24 

ziczac, Aturia ___________________________________ 54 

Zostera_____ _ ________________________ 21 

sp _________________________________________ 20 
PLATES 1-17 

[Contact photographs of the plates in this report are available, at cost, from U.S. Geological Survey Library, Federal 

Center, Denver, Colo. 80225.] 
PLATE 1 

FIGURES 1-4. Architectonica blanda Dall, p. 29 

1-3. Height (incomplete) 10.0 mm, width (incomplete) 14.0 mm. Locality USGS 15588. USNM 213945. 

4. Height (incomplete) 8.5 mm, width (incomplete) 14.0 mm. Locality USGS 15588. USNM 213946. 

5,8. Crepidula pileum (Gabb), p. 31 

Height 4.5 mm, width 8mm, length 18 mm. Locality USGS 15310. USNM 213947. 

6,7. Unidentified trochid?, p. 29 

Height (incomplete) 18.3 mm, width (incomplete) 24.8 mm. Locality USGS 15312. USNM 213948. 

9, 12, 13, 15, 16, 18, 19, 23. Cryptonatica pittsburgensis, n. sp., p. 31 

9. Height (incomplete) 19.0 mm, width 12.1 mm. Locality USGS 15310. USNM 213949. 

12. Height (incomplete) 17.8 mm, width (incomplete) 16.9 mm. Locality USGS 15588. USNM 213950. 

13. Height (incomplete) 16.0 mm, width (incomplete) 14.0 mm. Locality USGS 15310h. USNM 213951. 

15, 23. Height (incomplete) 18.4 mm1 width 18.0 mm. Locality USGS 15310. USNM 213952. 

16. Height (incomplete) 18.4 mm, width (incomplete) 18.6 mm. Locality USGS 15588. USNM 213953. 

18. Height (incomplete) 12.5 mm, width 12.5 mm. Locality USGS 2714. USNM 213954. 

19. Height 11.9 mm, width (incomplete) 11.0 mm. Locality USGS 15310. USNM 213955. 

10, 11. Sinum aff. S. obliquum (Gabb), p. 33 

Height (incomplete) 8. 7 mm, width (incomplete) 9.2 mm. Locality USGS 15264. USNM 213956. 

14, 17, 20--22, 24. Polinices washingtonensis (Weaver), p. 32 

14, 22. Height (incomplete) 24.2 mm, width 23.7 mm. Locality USGS 15310. USNM 213957. 

17. Height(incomplete) 17.4 mm, width (incomplete) 17.9 mm. Locality USGS 15310h. USNM 213958. 

20. Height (incomplete) 23.8 mm, width (incomplete) 23.4 mm. Locality USGS 15310h. USNM 213959. 

21. Height (incomplete) 29.8 mm, width (incomplete) 27.6 mm. Locality USGS 15588. USNM 213960. 

24. Height (incomplete) 21.0 mm, width 19.7 mm. Locality USGS 15310h. USNM 213961. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE I 

5 

9 

17 18 19 

22 23 

2 1 24 

ARCHITECTONICA, CREPIDULA, UNIDENTIFED TROCHID?, CRYPTONATICA ,SJNUM, AND POLINICES 
PLATE 2 

FIGURES 1- 15. Neverita (Glossaulax) thomsonae Hickman, p. 32 

1. Height (incomplete) 34.0 mm, width (incomplete) 36.5 mm. Locality USGS 

15264. USNM 213962. 

2,5. Height (incomplete) 36.0 mm, width (incomplete) 41.2 mm. Locality USGS 

5394. USNM 213963. 

3. Height (incomplete) 39.6 mm, width (incomplete) 37.7 mm. Locality USGS 

15264. USNM 213964. 

4. Height (incomplete) 43.3 mm, width (incomplete) 45.2 mm. Locality USGS 

15264. USNM 213965. 

6. Height (incomplete) 21.5 mm, width (incomplete) 21.7 mm. Locality USGS 

M3878. USNM 213966. 

7. Height (incomplete) 24.7 mm, width (incomplete) 29.0 mm. Locality USGS 

M3857. USNM 213967. 

8, 12. Height 19.8 mm, width (incomplete) 23.3 mm. Locality USGS 15310. 

USNM 213968. 

9. Height 15.3 mm, width (incomplete) 10.4 mm. Locality USGS 15310. USNM 

213969. 

10. Height 44.7 mm, width 49.6 mm. Locality USGS 15264. USNM 213970. 

11. Height 18.3 mm, width 19.6 mm. Locality USGS 15310. USNM 213971. 

13. Height 23.1 mm, width (incomplete) 27.3 mm. Locality USGS 15310. USNM 

213972. 

14. Height 52.5 mm, width (incomplete) 46.5 mm. Locality USGS 15310. USNM 

213973. 

15. Height (incomplete) 36.0 mm, width (incomplete) 36.6 mm. Locality USGS 

M3871. USNM 213974. 
PROFESSIONAL PAPER 922 PLATE 2 

GEOLOCICAL SURVEY 

3 

7 

9 

) 

15 

14 

13 

NEVERITA 
PLATE 3 

FIGURES 1-5, 21-23. Bruclarkia columbiana (Anderson and Martin), p. 34 

1. Height (incomplete) 59.5 mm, width (incomplete) 48.3 mm. Locality USGS 15264. USNM 

213975. 

2. Height 12.6 mm, width (incomplete) 8.0 mm. Locality USGS 15310. USNM 213976. 

3, 4. Height (incomplete) 5.6 mm, width (incomplete) 3.5 mm. Locality USGS 15310. USNM 

213977. Note protoconch on figure 3. 

5. Height (incomplete) 44.7 mm, width (incomplete) 30.5 mm. Locality USGS 15264. USNM 

213978. 

21, 23. Height (incomplete) 68.5 mm, width (incomplete) 52.7 mm. Locality USGS 15588. 

USNM 213979. 

22. Height (incomplete) 59.5 mm, width (incomplete) 14.5 mm. Locality USGS 15310. USNM 

213980. 

6, 8, 20. Opalia (Dentiscala?) hertleini, n. sp., p. 30 

6. Height (incomplete) 6.6 mm, width 3.8 mm. Locality USGS 21612. USNM 213981. 

8. Height (incomplete) 13.2 mm, width (incomplete) 8.1 mm. Locality USGS 15588. USNM 

213982. 

20. Holotype. Height (incomplete) 29.7 mm, width (incomplete) 12.0 mm. Locality USGS 15588. 

USNM 213983. 

7, 9, 10. Odostomia winlockiana Effinger, p. 40 

7. Height (incomplete) 4.5 mm, width 2.2 mm. Locality USGS 5329, Gries Ranch Formation. On 

the Nehalem road about 14,871 feet south of Clatskanie, sec. 24, T. 7 N. , R. 5 W. , Oregon. 

USNM 213984. 

9, 10. Height 2.5 mm, width 1.0 mm. Locality USGS 15310. USNM 213985. 

11- 16. Turritella pittsburgensis, n. sp., p. 29 

11. Height (incomplete) 21 mm, width 6 mm. Locality USGS 15278. USNM 213986. 

12. Height (incomplete) 30 mm, width 11 mm. Locality USGS 15519. USNM 213987. 

13. Height (incomplete) 33 mm, width 12 mm. Locality USGS 15519. USNM 213988. 

14. Height (incomplete) 21 mm, width 8 mm. Locality USGS 15278. USNM 213989. 

15. Height (incomplete) 30 mm, width 11 mm. Locality USGS 15519. USNM 213990. 

16. Holotype. Height (incomplete) 28.6 mm, width (incomplete) 10.7 mm. Locality USGS 15588. 

USNM 213991. 

17-19. Priscofusus stewarti (Tegland), p. 36 

17, 19. Height (incomplete) 29.6 mm, width 12.7 mm. Locality USGS 15264. USNM 213992. 

18. Height (incomplete) 16.7 mm, width (incomplete) 10.6 mm. Locality USGS M3871. USNM 

213993. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 3 

3 

4 

7 x1 Xr 

8 

6 

5 

9 10 x2 x1 Y:z 

x2 

11 

13 14 15 

18 

21 

23 

22 

BRUCLARKIA, OPALIA, ODOSTOMIA, TURRITELLA,AND PRISCOFUSUS 
PLATE 4 

FIGURES 1- 9. Eosiphonalia oregonensis (Dall) p. 33 

1, 3. Height 39.2 mm, width 27.5 mm. Locality USGS 15310. USNM 213994. 

2. Height 30.4 mm, width 23.2 mm. Locality USGS 15264. USNM 213995. 

4, 6. Holotype. Height 30 mm, width 21 mm. Locality UW 500. In fine-grained 

brownish-gray sandstone in road cut near Pittsburg, Columbia County, Oreg. 

USNM 107395. 

5, 8. Height 32.8 mm, width 24.5 mm. Locality USGS 15264. USNM 213996. 

7, 9. Height 31.2 mm, width 23.7 mm. Locality USGS 15310. USNM 213997. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 4 

2 3 

7 

8 

EOSIPHONALIA 
PLATE 5 

FIGURES 1- 22. Molopophorus gabbi Dall, p. 35 

1, 2. Height (incomplete) 10.8 mm, width (incomplete) 7.5 mm. Locality USGS 15310f. USNM 

218998 

3, 6. Height (incomplete) 16.8 mm, width (incomplete) 12.6 mm. Locality USGS 15264. USNM 

213999. 

4. Protoconch. Locality USGS M3871. USNM 214000. 

5. Height (incomplete) 16.7 mm, width (incomplete) 13.7 mm. Locality USGS 15310. USNM 214001. 

7. Protoconch. Locality USGS M3857. USNM 214002. 

8. Height (incomplete) 25.4 mm, width (incomplete) 17.7 mm. Locality USGS 15310. USNM 214003. 

9. Height (incomplete) 17.3 mm, width (incomplete) 20.0 mm. Locality USGS 15310. USNM 214004. 

10. Height 27.8 mm, width 20.9 mm. Locality USGS 15310a. USNM 214005. 

11. Height 27.0 mm, width 21.3 mm. Locality USGS 15310. USNM 214006. 

12. Height 24.7 mm, width 20.0 mm. Locality USGS 15310. USNM 214007. 

13. Height (incomplete) 26.2 mm, width (incomplete) 20.7 mm. Locality USGS 15310. USNM 214008. 

14. Height (incomplete) 24.2 mm, width (incomplete) 19.2 mm. Locality USGS 15310. USNM 214009. 

15. Height (incomplete) 19.8 mm, width (incomplete) 16.6 mm, Locality USGS 15264. USNM 21410. 

16. Height 27.0 mm, width 20.1 mm. Locality USGS 15310. USNM 214011. 

17. Height 26.6 mrn, width 21.0 mm. Locality USGS 15310. USNM 214012. 

18. Height 24.7 rnrn, width (incomplete) 21.5 rnrn. Locality USGS 15310. USNM 214013. 

19, 22. Holotype. Height 19 rnrn, width 12 mm. Locality USGS 2714. USNM 107377. 

20. Height (incomplete) 23.7 rnrn, width (incomplete) 17.0 mm. Locality USGS 2415. USNM 214014. 

21. Paratype. Height (incomplete) 16 mm, width 11.5 rnm. Locality USGS 2714. USNM 214016. 
GEOLOGICAL SURVEY 

2 

20 21 

MOLOPOPHORUS 

6 

PROFESSIONAL PAPER 922 PLATE 5 

7 

.. 18 

22 
FIGURES 1, 4, 6, 7, 9, 

12--14, 18--20. 

PLATE 6 

Perse pittsburgensis Durham, p. 36 

1, 4. Height 32.3 mm, width (incomplete) 15.8 mm. Locality USGS 15264. USNM 214017. 

6. Height (incomplete) 21.0 mm, width (incomplete) 11.5 mm. Locality USGS 15310. USNM 

214018. 

7. Height (incomplete) 12.0 mm, width (incomplete) 10.0 mm. Locality USGS 15264. USNM 

214019. 

9. Height (incomplete) 6.7 mm, width (incomplete) 4.6 mm. Locality USGS 15588. USNM 

214020. 

12. Height (incomplete) 16.7 mm, width (incomplete) 12.2 mm. Locality USGS 15588. USNM 

214021. 

13. Height (incomplete) 17.6 mm, width (incomplete) 13.3 mm. Locality USGS 15588. USNM 

214022. 

14. Height (incomplete) 15.4 mm, width (incomplete) 11.5 mm. Locality USGS 15588. USNM 

214023. 

18. Protoconch. Locality USGS 15264b. USNM 214024. 

19. Height (incomplete) 11.8 mm, width (incomplete) 9.8 mm. Locality USGS 15588. USNM 

214025. 

20. Height (incomplete) 13.5 mm, width (incomplete) 8.9 mm. Locality USGS 15588. USNM 

214026. 

2, 3, 5, 8, Perse pittsburgensis vernoniensis, n. subsp., p. 37 

10, 11, 15--17. 2, 3. Height (incomplete) 23.8 mm, width (incomplete) 14.6 mm. Locality USGS 15588. USNM 

214027. 

5, 8. Height (incomplete) 30.4 mm, width (incomplete) 15.1 mm. Locality USGS 15588. 

Holotype USNM 214028. 

10. Height (incomplete) 23.4 mm, width (incomplete) 13.0 mm. Locality USGS 15588. USNM 

214029. 

11. Height (incomplete) 27.6 mm, width (incomplete) 19.4 mm. Locality USGS 15588. USNM 

214030. 

15. Height (incomplete) 24.3 mm, width (incomplete) 16.7 mm. Locality USGS 15588. USNM 

214031. 

16. Height (incomplete) 28.0 mm, width (incomplete) 15.2 mm, Locality USGS 15588. USNM 

214032. 

17. Height (incomplete) 23.0 mm, width (incomplete) 11.6 mm. Locality USGS 15588. USNM 

214033. 
PROFESSiONAL PAPER 9'22 PLATE 6 

GEOLOGiCAL SURVEY 

... 

3 

1 2 

9 

7 

8 10 

6 

13 

12 

18 

20 

16 

17 PERSE 
PLATE 7 

FIGURES 1, 9,.10, 13. Spirotropis kincaidi (Weaver), p. 39 

1. Protoconch. Height (incomplete) 10.4 mm, width (incomplete) 6.4 mm. Locality USGS M3871. USNM 214034. 

9. Height (incomplete) 17.2 mm, width (incomplete) 7.8 mm. Locality USGS 15588. USNM 214035. 

10. Height 15.1 mm, width (incomplete) 7.3 mm. Locality USGS 15310a. USNM 225304. 

13. Height (incomplete) 6.3 mm, width (incomplete) 5.0 mm. Locality USGS 15264. USNM 214036. 

2, 3, 5-8, 16, 37. Taranis columbiana (Anderson and Martin) p. 38 

4, 11, 12, 15 , 

33--36, 38. 

14, 17. 

18, 23--32. 

2. Height (incomplete) 10.7 mm, width (incomplete) 5.0 mm. Locality USGS 15264a. USNM 214037. 

3. Height (incomplete) 7.7 mm, width (incomplete) 4.7 mm. Locality USGS 15264. USNM 214038. 

5. Height (incomplete) 10.8 mm, width 4.9 mm. Locality USGS M3871. USNM 214039. 

6. Smooth-keeled form. Height (incomplete) 10.9 mm, width (incomplete) 6.1 mm. Locality USGS M3871. USNM 

214040. 

7. Height (incomplete) 8.1 mm, width (incomplete) 4.3 mm. Locality USGS 15310. USNM 214041. 

8. Protoconch. Height 10.0 mm, width (incomplete) 4.8 mm. Locality USGS M3871. USNM 214042. 

16. Smooth-keeled form. Height (incomplete) 9.6 mm, width (incomplete) 5.0 mm. Locality USGS 15264b. USNM 

214043. 

37. Intermediate form. Height (incomplete) 11.4 mm, width (incomplete) 5.7 mm. Locality USGS 15310. USNM 

214044. 

Suavodrillia winlockensis (Effinger), p. 40 

4. Protoconch. Height (incomplete) 8.0 mm, width (incomplete) 4.0 mm. Locality USGS 15310a. USNM 214045. 

11. Height (incomplete) 3.5 mm, width (incomplete) 1.8 mm. Locality USGS 15310. USNM 214046. 

12. Height (incomplete) 10.2 mm, width (incomplete) 4.4 mm. Locality USGS 15310. USNM 214047. 

15. Height (incomplete) 4.9 mm, width 2.4 mm. Locality USGS 15310. USNM 214048. 

33. Height (incomplete) 6.0 mm, width 3.3 mm. Locality USGS 15264b. USNM 214049. 

34. Height (incomplete) 5.1 mm, width (incomplete) 2.2 mm. Locality USGS 15310. USNM 214050. 

35, 36. Height 10.6 mm, width 4.5 mm. Locality USGS 15310a. USNM 214051. 

38. Height (incomplete) 6.9 mm, width 3.2 mm. Locality USGS 15310. USNM 214052. 

Dentalium (Fissidentalium?) laneensis Hickman, p. 41 

14. Length (incomplete) 19.0, diameter: greatest 5.2 mm, least 3.3 mm. Locality USGS 2723. USNM 214053. 

17. Length (incomplete) 30.6 mm, diameter: greatest 10.0 mm, least 5.3 mm. Locality USGS 15264. USNM 214054. 

Scaphander stewarti Durham, p. 41 

18, 29. Height (incomplete) 10.9 mm, width (incomplete) 6.0 mm. Locality USGS 15264. USNM 214055. 

23. Height (incomplete) 9.8 mm, width (incomplete) 5.0 mm. Locality USGS 15264b. USNM 214056. 

24, 27. Height (incomplete) 8.8 mm, width 4.9 mm. Locality USGS 18638. USNM 214057. 

25, 26. Height (incomplete) 13.8 mm, width (distorted) 8.3 mm. Locality USGS 15310. USNM 214058. 

28. Height (~ncomplete) 10.7 mm, width (incomplete) 6.1 mm. Locality USGS 15264b. USNM 214059. 

30, 31. Height 12.1 mm, width 7.6 mm. Locality USGS 15588. USNM 214060. 

32. Height (incomplete) 9.4 mm, width 9.0 mm. Locality USGS 2714. USNM 214061. 

19. Acteon? n. sp.?, p. 41 

Height (incomplete) 4.1 mm, width (incomplete) 3.0 mm. Locality USGS 15588. USNM 214062. 

20, 21. Acteon chehalisensis (Weaver), p. 40 

20. Height (incomplete) 8.2 mm, width (incomplete) 4.4 mm. Locality USGS 15264. USNM 214063. 

21. Height (incomplete) 10.0 mm, width (incomplete) 5.4 mm. Locality USGS 15588. USNM 214064. 

22. Aforia campbelli Durham, p. 37 

Height (incomplete) 28.0 mm, width (incomplete) 21.0 mm. Locality USGS 15519. USNM 214065. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 7 

4 

x5 

~ 8 x2Y2 

2 7 

3 6 

~ 

~ x2 

5 

11 

16 

9 

x1 ~ 

12 

10 14 

13 

19 x1% 

18 20 21 

17 22 

28 

23 24 27 

25 26 

x3 

29 32 

30 31 

33 34 

35 37 38 

36 

SPIROTROPIS, TARANIS, SUAVODRILLIA, DENT ALlUM, SCAPHANDER, ACTEON?, ACTEON,AND APORIA 
FIGURES 1-9, 11, 12, 

14, 15, 18. 

PLATE 8 

Acila (Truncacila) shumardi (Dal!), p. 42 

1. Length 18.0 mm, width (both valves) 9.7 mm, height 13.4 mm. Locality USGS 15264. USNM 

214066. 

2, 3, 7. Length 24.4 mm, width 14.5 mm, height 18.7 mm, Locality USGS 2714. USNM 107 402. 

2. End view of escutcheon. 

3. Left valve. 

7. Top view of lunule. 

4. Length 28.0 mm, width 7.7 mm, height 20.2 mm. Locality USGS 15310. USNM 214067. 

5, 6. Holotype. Length 24.2 mm, height 17.8 mm. Locality USGS 2714. USNM 406405. 

8. Length 26.2 mm, width (one valve) 7.5 mm, height 19.9 mm. Locality USGS 15588. USNM 

214068. 

9. Length 14.1 mm, width (one valve) 4.5 mm, height 10.3 mm. Locality USGS 15264. USNM 

214069. 

11. Length 25.1 mm, width (one valve) 7.3 mm, height 19.3 mm. Locality USGS 15264. USNM 

214070. 

12. Hinge. Length 23.0 mm, height 16.8 mm. Locality USGS M3871. USNM 214071. 

14. Hinge. Length (incomplete) 22.9 mm, height (incomplete) 18.0 mm. Locality USGS M3871. 

USNM 214072. 

15. Hinge. Length 26.6 mm, height 19.9 mm. Locality USGS M3871. USNM 214073. 

18. Hinge. Length 23.3 mm, height 16.9 mm. Locality USGS M3871. USNM 214074. 

10, 13, 16, 17. Nucula (Leionucula ) vokesi , n . sp., p. 42 

10. Holotype. Length 6.5 mm, height 4.7 mm. Locality USGS 18638. USNM 214075. 

13. Length 7.5 mm, width 3.2 mm, height 5.7 mm. Locality USGS 2714. USNM 214076. 

16. Hinge, left valve . Locality USGS 18638. USNM 214077. 

17. Hinge, right va lve. Locality USGS 18638. USNM 214078. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 8 

2 3 

4 

6 

5 7 8 

9 11 

10 

14 

12 13 

x5 

x5 

18 

15 

ACILA AND NUCULA 
PLATE 9 

FIGURES 1- 10, 12. Litorhadia washingtonensis (Weaver) p. 43 

1. Length (incomplete) 22.7 mm, height (incomplete) 12.3 mm, width 3.0 mm. Locality USGS 

15310. USNM 214079. 

2, 8. Length (incomplete) 17.1 mm, height (incomplete) 8.1 mm. Locality USGS 19004, Lincoln 

Creek Formation, Washington. USNM 214080. 

3. Length (incomplete) 23 mm, height (incomplete) 12 mm. Locality USGS 15310. USNM 214081. 

4. Length (incomplete) 17.6 mm, height (incomplete) 10.5 mm. Locality USGS 18638. USNM 

214082. 

5. Length (incomplete) 20.4 mm, height 10.2 mm. Locality USGS 15310. USNM 214083. 

6. Length (incomplete) 19.5 mm, height (incomplet e) 9.3 mm. Locality USGS 18638. USNM 

214084. 

7. Length (incomplete) 16.2 mm, height (incomplete) 7.5 mm. Locality USGS 15310. USNM 

214085. 

9. Length (incomplete) 11.0 mm, height (incomplete) 5.2 mm. Locality USGS 15588. USNM 

214086. 

10. Length 20.0 mm, height 9.3 mm. Locality USGS 15264. USNM 214087. 

12. Length 29.2 mm, height 13.7 mm. Locality USGS 15588. USNM 214088. 

11, 13, 15. Cyclocardia (Cyclocardia ) cf. C. (C.) hannibali (Clark), p. 45 

11. Length (incomplete) 17.6 mm, height (incomplete) 17.8 mm. Locality USGS 15537. USNM 

214089. 

13. Length (incomplete) 15.5 mm, height (incomplete) 12.0 mm. Locality USGS 15537. USNM 

214090. 

15. Right valve and hinge of left valve. Length (incomplete) 14.0 mm, height (incomplete) 13.0 

mm. Locality USGS 15537. USNM 214091. 

14, 16--18. Y oldia (Kalayoldia ) oregona (Shumard), p. 44 

14. Length (incomplete) 43 mm, height 28.0 mm. Locality USGS 15586. USNM 214092. 

16. Hinge. Locality USGS 15310a. USNM 214093. 

17. Length (incomplete) 41.4 mm, height 23.0 mm. Locality USGS 15586. USNM 214094. 

18. Length (incomplete) 51 mm, height (incomplete) 23 mm. Locality USGS 15264e. USNM 

214095. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER PLATE 9 

2 3 

6 

4 

8 9 ' 

7 

11 12 

10 

13 

14 

15 

x3 

16 

18 

17 

LITORHADIA, CYCLOCARDIA, AND YOLDIA 
PLATE 10 

FIGURES 1-8. Lucinoma columbiana (Clark and Arnold), p. 45 

1. Length (incomplete) 18.7 mm, height 15.5 mm. Locality USGS 15588. USNM 

214096. 

2, 3, 6--8. Length (incomplete) 21.2 mm, height 20.0 mm, width (both valves) 

11.6 mm. Locality USGS 15588. USNM 214097. 

4, 5. Length 11.0 mm, height 10.3 mm, width (one valve) 2.3 mm, Locality 

USGS 15588. USNM 214098. 

9-11. Felaniella (Felaniella) snavelyi, n. sp., p. 46 

9. Length 14.6 mm, height 13.0 mm. Locality USGS 15586. USNM 214099. 

10. Holotype. Length 21.6 mm, height 19.6 mm, width (one valve) 4.2 mm. 

Locality USGS 15264. USNM 214100. 

11. Length (incomplete) 15.0 mm, height 22.0 mm. Locality USGS 15310. 

USNM 214101. 

12--14. Nemocardium (Keenaea) lorenzanum (Arnold), p. 47 

12. Length (incomplete) 11 mm, height (incomplete) 10.0 mm. Locality USGS 

18638. USNM 214102. 

13. Length 12.3 mm, height 11.0 mm. Locality USGS 15264. USNM 214103. 

14. Height 4.5 mm, length 4.6 mm. Locality USGS 18638. USNM 214104. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 10 

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LUCINOMA, FELANIELLA, AND NEMOCARDIUM 
PLATE 11 

FIGURES 1-6. Tellina? pittsburgensis Clark, p. 51 

1. Hinge. Locality USGS 15264. USNM 214105. 

2. Hinge. Locality USGS 15264. USNM 214106. 

3. Length (incomplete) 13.7 mm, height (incomplete) 8.4 mm. Locality USGS 

15586. USNM 214107. 

4. Length (incomplete) 15.6 mm, height (incomplete) 9.6 mm. Locality USGS 

15586. USNM 214108. 

5. Dorsal view. Length (incomplete) 22 mm, height 13.4 mm, width (both valves) 

5.4 mm. Locality USGS 15264. USNM 214109. 

6. Height 13.3 mm, length (incomplete) 21.6 mm. Locality USGS 15264. USNM 

214110. 

7- 12. Tellina (Eurytellina) aduncanasa Hickman, p. 50 

7. Length (incomplete) 36 mm, height (incomplete) 20 mm. Locality USGS 15588. 

USNM 214111. 

8, 11, 12. Length (incomplete) 18.6 mm, height (incomplete) 9.7 mm, width (both 

valves) 2.8 mm. Locality USGS 15264. USNM 214112. 

9. Length (incomplete) 39 mm, height (incomplete) 19 mm. Locality USGS 

15:310b. USNM 214113. 

10. Length (incomplete) 27 mm, height (incomplete) 14 mm. Locality USGS 

15586. USNM 214114. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATEll 

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TELLINA? AND TELLINA 
PLATE 12 

FIGURES 1, 2, 4. Pitar (Pitar) dalli (Weaver), p. 47 

1, 4. Length (incomplete) 65 mm, height (incomplete) 46 mm, width (both valves, internal mold) 

28.5 mm. Locality USGS 15532. USNM 214115. 

2. Left hinge. Locality USGS 15310a. USNM 214116. 

3, 5-11, 13. Callista (Macrocallista) pittsburgensis Da11 , p. 48 

3. Left hinge. Length 13.0 mm, height 8.6 mm. Locality USGS 15264. USNM 214177. 

5. Left hinge. Length 19.3 mm, height 13.0 mm. Locality USGS 15264. USNM 214118. 

6. Length (incomplete) 42 mm, height 24.3 mm. Locality USGS 15264. USNM 214119. 

7, 9. Length 34.0 mm, height 21.4 mm, width (one valve) 6.1 mm. Locality USGS 15264. USNM 

214120. 

8. Length (incomplete) 22.0 mm, height 16.5 mm. Locality USGS 15264. USNM 214121. 

10. Right hinge. Length (incomplete) 7.1 mm, height (incomplete) 4.9 mm. Locality USGS 18638. 

USNM 214122. 

11. Paratype. Length (incomplete) 31 mm, height (incomplete) 22 mm. Locality USGS 2714. 

USNM 107399. 

13. Lectotype. Length (incomplete) 36 mm, height (incomplete) 21 mm. Locality USGS 2714. 

USNM 107396. 

12. Crenella porterensis Weaver, p. 45 

Length (incomplete) 5.0 mm, height (incomplete) 5.4 mm. Locality USGS 15583. USNM 214123. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLAT£12 

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11 12 13 

PITAR, CALLISTA, AND CRENELLA 
PLATE 13 

FIGURES 1, 2, 6. Solena (Eosolen) eugenensis (Clark), p. 52 

1. Hinge of left valve. Length (incomplete) 87 mm, height 

(incomplete) 21 mm. Locality USGS 15588. USNM 214124. 

2. Length (incomplete) 70 mm, height (incomplete) 26 mm, 

width (both valves, compressed) 12.7 mm. Locality USGS 

15588. USNM 214125. 

6. Interior ofleft valve. Locality USGS 15588. USNM 214126. 

3-5. Solen townsendensis Clark, p. 51 

3, 5. Length (incomplete) 54 mm, height (incomplete 14 mm, 

width (one valve) 3.5 mm. Locality USGS 15310. USNM 

214127. 

4. Length (incomplete) 21 mm, height 5.6 mm. Locality USGS 

15264. USNM 214128. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 13 

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SOLEN A AND SOLEN 
PLATE 14 

FIGURES 1, 2, 9. Spisula (Mactromeris?) veneriformis Clark, p. 50 

1. Rubber impression of left hinge. Locality USGS 15516. USNM 214129. 

2. Rubber impression of right hinge. Locality USGS 15516. USNM 214130. 

9. Length (incomplete) 83.2 mm, height (incomplete) 70.9 mm. Locality 

USGS 15516. USNM 214131. 

3-8, 10, 11. Spisula (Mactromeris) pittsburgensis Clark, p. 49 

3. Right hinge. Length (incomplete) 48 mm, height (incomplete) 34 mm, 

width (one valve) 9.7 mm. Locality USGS 15310d. USNM 214132. 

4. Right hinge. Length (incomplete) 49 mm, height (incomplete) 36 mm. 

Locality USGS 15586. USNM 214133. 

5. Left hinge. Length 32.1 mm, height 22.7 mm. Locality USGS 15264. 

USNM 214134. 

6, 10, 11. Length (incomplete) 56.2 mm, height 39.6 mm, width (both valves) 

21.0 mm. Locality USGS 15588. USNM 214135. 

7. Right hinge. Locality USGS 18638. USNM 214136. 

8. Left hinge. Locality USGS 15310b. USNM 214137. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 14 

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SPISULA 
FIGURES 

PLATE 15 

1- 3. Panopea ramonensis Clark, p. 53 

1. Length 48.9 mm, height 28.5 mm. Locality USGS 15588. 

USNM 214138. 

2. Length (incomplete) 42.0 mm, height (incomplete) 27.0 mm, 

width (both valves) 18.9 mm. Locality USGS 15499. USNM 

214139. 

3. Length (incomplete) 45 mm, height (incomplete) 34 mm, 

width (both valves) 22.6 mm. Locality USGS 15588. USNM 

214140. 

4. Aturia angustata (Conrad), p. 54 

Height (incomplete) 30 mm, width (incomplete) 30 mm. Locality; 

roadcut on Scappoose-Vernonia road, about 2 mi from the 

junction with State Highway 47. USNM 214142. 

5. Panopea snohomishensis Clark, p. 52 

Length 83.4 mm, height (incomplete) 52.3 mm. Locality USGS 

15516. USNM 214141. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 15 

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PANOPEA AND ATURIA 
PLATE 16 

FIGURES 1, 3. Thracia (Thracia) condoni Dall, p. 54 

Length (incomplet e) 46.7 mm, height (incomplete) 34.7 mm. 

Locality USGS 15586. USNM 214143. 

2, 5. ?Ervilia oregonensis Dall, p. 50 

Length (incomplete) 10.5 mm, height (incomplete) 7.0 mm. 

Locality USGS 18638. USNM 214144. 

4, 6--11. Cochlodesma bainbridgensis Clark, p. 53 

4, 8. Length (incomplete) 34.1 mm, height (incomplete) 21 mm, 

width (both valves) 8.2 mm. Locality USGS M3872. USNM 

214146. 

6. Length (incomplete) 40.0 mm, height (incomplete) 29 mm. 

Locality USGS 15519. USNM 214145. 

7. Length (incomplete) 32.5 mm, height (incomplete) 23.5 mm. 

Locality USGS 15588. USNM 225305. 

9. Condrophore with mineralized resilium. Length (incomplete) 

42 mm, height (incomplete) 30 mm. Locality USGS 15588. 

USNM 214147. 

10. Length (incomplete) 53 mm, height (incomplete) 35 mm. 

Locality USGS 15583. USNM 214148. 

11. Length (incomplete) 32 mm, height (incomplete) 23 mm. 

Locality USGS 15588. USNM 214149. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE 16 

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THRACIA, ?ER VI LIA, AND COCHLODESMA 
PLATE 17 

Two fossiliferous slabs from USGS locality 15310 in the Pittsburg Bluff Formation showing typical groupings of naticids, Molopophorus, Perse, Acila, and 

Macrocallista. Natural size. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 922 PLATE I 7 

NATICIDS; MOLOPOPHORUS, PERSE, ACILA, AND MACROCALLISTA