Biostratigraphy of the Marine 

Neogene Sequence at Cape Blanco, 

Southwestern Oregon 

G E 0 L 0 G I C A L S U R V E Y P R 0 FE S S I 0 N A L P A P E R 7-7 4 - G 

Biostratigraphy of the Marine 

Neogene Sequence at Cape Blanco, 

Southwestern Oregon 

By WARREN 0. ADDICOTT 

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 774-G 

A study of fossiliferous marine sandstone 

constituting two unconformity-bounded 

sequences of early and middle Miocene 

and of late Miocene age 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1983 
UNITED STATES DEPARTMENT OF THE INTERIOR 

JAMES G. WATT, Secretary 

Addicott, Warren 0., 1930-

GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Library of Congress Cataloging in Publication Data 

Biostratigraphy of the marine Neogene sequence at Cape Blanco, southwestern Oregon. 

(Geological Survey professional paper 774-G) (Shorter contributions to general geology) 

Bibliography:p. 16-17 

Includes index. 

Supt. ofDocs. no.: I 19.16:774-G 

1. Paleontology-Tertiary. 2. Paleontology-Oregon-Blanco, Cape. I. Title. II. Series: United States. Geological 

Survey. Professional Paper 774-G. III. Series: Shorter contributions to general geology. 

QE691.A32 1983 564 83-000052 

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

604 South Pickett Street, Alexandria, VA 22304 
CONTENTS 

Page 

Abstract _____________________________________________________________________________________________________________________________________________________________ G1 

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

Previous studies________________________________________________________________________________________________________________________________________ 2 

Stratigraphic setting-------------------------------------------------------------------------------------------------------------------------------------- 3 

Paleontology of the sandstone of Floras Lake------------------------------------------------------------------------------------------ 8 

Invertebrate macrofauna ---------------------------------------------------------------------------------------------------------------------- 8 

Provincial age ------------------------------------------------------------------------------------------------------------------------------------------ 8 

Correlation --------------------------------------------------------------------------------------------------------------------------·--------------------- 9 

Paleoecology---------------------------------------------------------------------------------------------------------------------------------------------- 10 

Paleontology of the restricted Empire Formation -------------------------------------------------------------------------------- 11 

Age and provenance of Scutella blancoensis Kew -------------------------------------------------------------------------- 14 

References cited ---------------------------------------------------------------------------------------------------------------------------------------------- 16 

Index ____________________________________________________________________________________________________________________________________________________________________ 19 

ILLUSTRATIONS 

[Plates follow index] 

PLATE 1. Nucella, Bruclarkia, Cancellaria, Poh"nices, Natica, Priscofusus, Molopophorus, Liracassz:s, Crepidula, Megasurcula, Yoldia, 

Solen, Ophiodennella, Spisu1a, Tellina. 

2. Mytz:lus, Nucella, Katherinella, Macorna, Crep,idula, Cancellaria, Kewia, Oliuella, Priscofusus, Tel/ina, Nassarius, 

Cryptonatica, Securella, Spisula. 

3. Clinocardiunz, Siliqzw, Crepidula, Acz:ta, Calliostorna, Chlarnys, Trophonopsis, Glycymen:s, Nassarius, Nucella, Felaniella, 

Molopophorus, Kewia, Opalia, Securella. 

Page 

FIGURE 1. Index map of Pacific coast of the United States, showing location of Cape Blanco ----------------------------------- ---------------------------------------- G1 

2. Sketch map of Cape Blanco-Blacklock Point area, showing megainvertebrate-fossillocalities ------------------------------------------------------ 3 

3. Sketch of seacliff section of sandstone of Floras Lake---------------------------------------------------------------------------------------------------------------------------------- 4 

4-8. Photographs showing: 

4. Buff sandstone of the restricted Empire Formation ---------------------------------------------------------------------------------------------------------------------- 4 

5. Concretionary sandstone and pebble conglomerate of basal part of sandstone of Floras Lake at Fin Rock __________________ 6 

6. Seacliff exposure of sandstone of Floras Lake southeast of Cape Blanco---------------------------------------------------------------------------------- 7 

7. Unconformable contact between Mytilus middendorffi-bearing sandstone of Floras Lake and the restricted Empire 

Formation southeast of lighthouse at Cape Blanco------------------------------------------------------------------------------------------------------------------ 8 

8. Angular unconformity between the restricted Empire Formation and the Port Orford Formation of Baldwin (1945)____ 10 

9. Chart showing correlation of Neogene formations exposed at Cape Blanco with Pacific Northwest Tertiary molluscan 

chronology -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 10 

10. Photograph showing unconformable contact between sandstone of Floras Lake and the restricted Empire Formation________ 12 

11. Photograph showing unconformable contact between the restricted Empire Formation and the Port Orford Formation__________ 15 

12. Photograph showing Psephidia beds in upper part of the Port Orford Formation of Baldwin (1945) exposed near Elk River____ 16 

TABLES 

Page 

TABLE 1. Marine macroinvertebrates from the sandstone of Floras Lake (lower part of the Empire Formation of Diller, 1903) exposed 

near Cape Blanco, Oregon----------------------------------------------------------------------------------------------------------------------------------------------------------------------'------- G9 

2. Provincial stratigraphic range of species in the Cape Blanco Newportian fauna, with notes on their occurrence in the California Neogene molluscan province __ ____________________ ____ __ __ __ _________ __ ____ ____ _______ ____ __ __ ___________ __ __ _________________ __ __ __ __ __ __ ________ _________ __ ____ __________ _______ ____ __ 11 

3. Late Miocene (Wishkahan) macroinvertebrates from the lower part of the restricted Empire Formation near Cape Blanco, 

Oregon·----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 13 

III 

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

BIOSTRATIGRAPHY OF THE MARINE NEOGENE SEQUENCE AT 

CAPE BLANCO, SOUTHWESTERN OREGON 

By wARREN 0. ADDICOTT 

ABSTRACT 

A shallow-water marine sandstone sequence-the Empire Formation of Diller (1903)-exposed at and near Cape Branco, southwestern Oregon, contains molluscan assemblages referable to th€ 

provincial Newportian, Wishkahan, and, probably, Graysian Stages. 

Sandy siltstone from the stratigraphically highest part of the 

sequence contains siliceous microfossils coeval with assemblages 

that occur in the type section of the provincial Graysian Stage in 

southwestern Washington. All but the earliest Miocene seems to be 

represented in this 260-m-thick shallow-water sequence. Although 

Pliocene strata are not preserved, this nevertheless constitutes the 

most complete marine Neogene sequence in Oregon. 

An unconformity within the sandstone sequence separates the 

lower strata containing the N ewportian assemblages from stratigraphically higher strata containing the Wishkahan assemblages. 

The lower strata-160m of sandstone, conglomerate, and tuff-are 

here called the sandstone of Floras Lake. Use of the name "Empire 

Formation" has been restricted to the upper 100m, sandstone and 

silty sandstone. The sandstone of Floras Lake contains a macroinvertebrate fauna that demonstrates the temporal equivalence of the 

N ewportian Stage with the "Temblor" Stage of California. The molluscan fauna from the lower concretionary sandstone of the overlying Empire Formation is coeval with the fauna in the type section of 

the Empire Formation at Coos Bay, about 60 km to the north. 

INTRODUCTION 

A sequence of shallow-water fossiliferous sandstone 

of Miocene age is exposed in a late Cenozoic section 

near Cape Blanco, southwestern Oregon (fig. 1). This 

sequence, commonly known as the Empire Formation 

of Diller (1903), contains rich but relatively low diversity assemblages of marine macrofossils, principally 

mollusks. Although the Pliocene is not represented in 

the section, the sequence nevertheless constitutes the 

most complete late Cenozoic section exposed on the 

Oregon coast. Possibly for this reason, it has received 

considerable study over the 120 years since its discovery (Newberry, 1856). However, composite stratigraphic collections of fossils and the absence of detailed 

biostratigraphic study have led to widely divergent 

age determinations on and correlations of these strata. 

The basal Miocene strata, here referred to as the 

sandstone of Floras Lake, are the focus of this report. 

These strata were included in the Empire Formation 

by Diller (1903), who correlated them with his type 

Empire Formation (Diller, 1899) at Coos Bay, about 60 

km to the north. Unbeknownst to Diller and later 

investigators, however, two distinct Miocene faunas 

separated by an unconformity are represented in his 

125° 120° 

45° 

0 

OREGON 

u 

....... 

w... 

....... ----- ___ ! _________ ----

u 1 

<( 

40° 0.. 

i NEVADA 

t_ 

" 

100 San Francisco 

FIGURE 1.-Pacific coast of the United States, showing location 

of Cape Blanco. 

G1 
G2 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

Empire Formation at Cape Blanco. The sandstone and 

the conglomerate lenses below the unconformity contain mollusks of early and middle Miocene age that are 

comparable to the fauna of the Astoria Formation of 

Oregon, as first noted by Durham (1953), whereas the 

lithologically similar sandstone above the unconformity contains an invertebrate macrofauna of late Miocene age and is in part coeval with the type Empire 

Formation at Coos Bay. 

This report documents the age of the 260-m sequence 

constituting the Empire Formation of Diller (1903) at 

Cape Blanco and discusses the age and correlation of 

the molluscan assemblages in this sequence. Emphasis 

is on the early and middle Miocene fauna of the 160-m 

section below the unconformity. These lower assemblages are referable to the provincial N ewportian Stage 

of Addicott (1976). Some of the confusion over the age 

of this shallow-water marine sequence can be traced to 

the fact that the only published faunal list from the 

Empire (Arnold and Hannibal, 1913, loc. NP26) was 

based on material from both above and below the 

unconformity. The fauna from the sandstone and siltstone overlying the unconformity, based on U.S. Geological Survey collections, is listed herein for the first 

time. The taxonomy of this late Miocene fauna is well 

known, owing to monographic treatment of the fauna 

of the Empire Formation at Coos Bay (Dall, 1909), 

some 60 km to the north, and to subsequent biostratigraphic studies of the type section between the Sitka 

dock and the bridge to Charleston (Weaver, 1945; 

Armentrout, 1967). 

Acknowledgments.-Invertebrate macrofauna! collections from the Miocene sequence were obtained in 

1964, 1968, 1969, 1971, 1977, and 1978. R. J. Janda 

assisted in securing fossil collections in 1969 and 1971; 

he also made available a sequence of black-and-white 

photographs of the seacliffs southeast of Cape Blanco 

from which the sketch section was constructed. Hiroshi N oda helped in stratigraphic sampling in 1978. 

E. M. Baldwin of the University of Oregon, Eugene, 

lent fossil material collected from the Cape Blanco 

section and discussed with me the sequence of his Neogene and Quaternary stratigraphic units (Baldwin, 

1945). J. A. Barron provided a late Miocene age determination based on a diatomaceous assemblage from 

near the top of the Miocene sequence southeast of Cape 

Blanco. Fossil photography is by Kenji Sakamoto. 

PREVIOUS STUDIES 

The many references to the age of the marine strata 

near Cape Blanco over the past 120 years point to a 

continuing interest in this unique coastal section of 

Neogene and Quaternary age. The provincial age and 

correlation of the sandstone and the congolomerate 

lenses in the lower part of the section have been subject 

to contradictory viewpoints because they were based, 

in large part, on a stratigraphically mixed collection 

(Arnold and Hannibal, 1913, loc. NP26) that spanned 

200m or more of section and included assemblages 

from what are now known to be two provincial stages, 

the N ewportian and the Wishkahan. A recapitulation 

of earlier work may help place the present study in 

proper perspective. 

Newberry (1856, p. 59) considered the marine Neogene strata that he recognized near Cape Blanco to be 

probably correlative with sandstone and shale at Astoria, Oreg., later described as the Astoria Formation. 

His report was cited by Dall and Harris (1892), who 

included these strata in the Neogene, and by Diller 

(1896), who assigned them to the Miocene. 

Diller (1902, 1903) was the first to describe and map 

the Neogene sequence near Cape Blanco. W. H. Dall (in 

Diller, 1902, p. 30-31) identified fossils from near the 

base of sandstone cropping out between Blacklock Point 

and Floras Lake, northeast of Cape Blanco, as Miocene 

and correlated the assemblage with the Empire Formation at Coos Bay. A thicker and lithological similar section southeast of Cape Blanco was assigned by Diller to 

the Empire Formation (as the "Empire beds") on the 

basis of paleontologic determinations by Dall. The lower 

120 to 150 m of this section and the Neogene section 

north of Blacklock Point were subsequently determined 

to be middle Miocene (Durham, 1953). 

The first molluscan assemblages recorded from 

these strata (Arnold and Hannibal, 1913, p. 590-591) 

included specimens from a locality between Blacklock 

Point and Floras Lake (3 species) and the stratigraphically mixed collection of Miocene species from southeast of Cape Blanco (24 species), referred to above. 

Arnold and Hannibal (1913, p. 590) considered the 

Empire Formation to be middle Miocene but younger 

than both the Astoria and the Clallam Formations, 

which they considered to be of "Oligocene-Miocene 

age." The Empire was correlated with formations that 

are now considered to be late Miocene. 

The age of the Empire Formation at Cape Blanco 

continued to be controversial for many years after 

Arnold and Hannibal's (1913) report. The exposures 

were considered to be as old as Oligocene by Kew 

(1920) on the basis of an echinoid (Scutella blancoensis), 

and as young as Pliocene (Schenck, 1928; Bandy, 1950). 

Other workers (Hertlein and Crickmay, 1925; Weaver, 

1942) considered the Empire Formation at Cape Blanco 

to be late Miocene and (or) early Pliocene. Schenck 

(1936, p. 95), who reviewed the problem of the age of 
BIOSTRATIGRAPHY OF THE MARINE NEOGENE SEQUENCE, CAPE BLANCO, OREGON G3 

the Empire Formation at Cape Blanco, pointed out the 

provincial Miocene affinities of Scutella blancoens£s 

Kew and the Pliocene affinities of the associated mollusks, as noted by other workers (see Howe, 1922). The 

age of the Empire Formation of Diller (1903) southeast 

of Cape Blanco was clarified by Durham (1953), who 

identified the unconformity within the formation at a 

point about lYz km southeast of Cape Blanco. This 

unconformity separates early or middle Miocene molluscan assemblages below from late Miocene assemblages coeval with the type Empire Formation at Coos 

Bay, Oreg., above. Durham's (1953) discovery explained the anomalous mixing of such middle Miocene 

species as Acna conradi, Myh~lus middendorjji, Nassarius arnoldi, Cancellaria oregonens1~s, and "Fusus" 

[Bruclarkia] stanfordensis with such characteristic 

late Miocene (then considered Pliocene) species as 

Card1:um [Clinocard?.um] meekt:anum, Calliostorna 

camman1~, and Thais precursor, all listed by Arno1d 

and Hannibal (1913). 

STRATIGRAPHIC SETTING 

Miocene sandstone unc-onformably overlies sandstone and pebbly mudstone of the Upper Jurassic 

Otter Point Formation at Cape Blanco (Dott, 1971), 

and middle Eocene shale and sandstone (Bandy, 1944) 

in the seacliff southeast of the cape. At Blacklock Point 

(fig. 2), about 6 km northeast of Cape Blanco, Miocene 

sandstone and pebble conglomerate unconformably 

overly sandstone and mudstone included by Dott 

(1971) in his Upper Cretaceous Hunters Cove Formation. 

All of the Neogene sequence exposed near Cape 

Blanco was included in the Empire Formation of 

Diller (1903); as I show, however, it seems advisable to 

restrict the use of this term to the upper part of the · 

sequence, which is late Miocene. The Empire at Cape 

Blanco is unconformably overlain by the Pleistocene 

Port Orford Formation of Baldwin {1945), a unit rich 

in molluscan fossils. Unconformably capping the late 

Cenozoic strata at Cape Blanco are marine-terrace 

deposits of late Pleistocene age. Mollusks and a few 

foraminifers have been identified from these strata 

(Addicott, 1964; Bandy, 1950). 

The Neogene sequence exposed between Blacklock 

Point and Floras Lake, a distance of about 3 to 4 km, 

consists of massive brown-weathering fine- to mediumgrained sandstone that forms prominent steep cliffs. 

Pebble- and cobble-conglomerate lenses, as much as Ij3 

m thick, are common in the lowest part of this seacliff 

section. Associated with the conglomerate lenses in the 

lowest 30 to 50 m of section is a low-diversity faunal 

assemblage of disarticulated Balanus plates, Mytaus 

middendorffi Grewingk, Nucella packi (Clark), and 

scattered poorly preserved aragonitic mollusks, including Molopophorus sp. and a naticid. A lYz- to 2-mthick gray thin-bedded pumiceous tuff bed occurs near 

the top of the exposed section. Concretionary beds in a 

15-m interval below the tuff bed contain common wellpreserved valves of M. middendorjj1: (USGS loc. 

M4130). The stratigraphically highest molluscan 

assemblage (USGS loc. M4132) occurs in concretionary strata exposed in a small gully opposite the middle 

part of Floras Lake; this assemblage includes M. middendorjji and other species characteristic of the Newportian Stage. 

The continuously exposed Neogene section of massive 

conglomeratic and concretionary sandstone that contains a tuff bed near the top constitutes the reference 

section for the sandstone of Floras Lake, an informal 

term developed by R. J. Janda (written commun., 

EXPLANATION 

~ Empire Formation (restricted) } .(upper part .of Empire Formation 

of Diller, 1903) 

Unconformity Miocene 

Sandstone of Floras Lake !IIIIIIlilJ (lower part of Empire 'Formation 

of Diller, 1903) 

USGS fossil locality 

(Menlo Park register) 

Blacklock Point 

M3755 

F-2011 

u 

D 

University of Oregon S 

fossil locality ?if 

Fault - Dashed where c§J 

approximately located 

U, upthrown side; 

D, downthrown side 

3 KILOMETERS 

124°30' 

T 31 S 

T 32 S 

42°50' 

FIGURE 2.-Cape Blanco-Blacklock Point area (Cape Blanco quadrangle), showing megainvertebrate-fossil localities. Modified 

from Dott (1962). 
G4 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

1975) to avoid use of the potentially confusing name 

"Empire Formation," in the sense of Diller (1903), for 

these earlier Miocene strata (Addicott, 1980). Accordingly, the use of the name "Empire Formation" in the 

Cape Blanco area has been restricted to those strata of 

late Miocene age (upper part of the Empire Formation 

of Diller, 1903) that unconformably overlie the sandstone of Floras Lake (lower part of Empire Formation 

of Diller, 1903) and unconformably underlie the Quaternary Port Orford Formation of Baldwin (1945) 

(Addicott, 1980). The restricted Empire (fig. 3) is lithologically similar to strata constituting the type section 

of the Empire Formation at Coos Bay, about 6 km to the 

north, and to exposures of the formation at intermediate points along the coast (Diller, 1903). This usage is 

also in close biostratigraphic agreement with the sections exposed at those places. 

The Empire Formation has been considered middle 

Miocene to Pliocene. The middle Miocene age (Durham, 1953; Moore, 1963) was based on strata in the 

Cape Blanco area (sandstone of Floras Lake) that are 

now excluded from the Empire. The Pliocene age 

(Diller, 1896; Howe, 1922; Weaver, 1945) was based on 

a much lower placement of the Miocene-Pliocene 

boundary in the provincial sequence-at 9-10 m.y.; 

this boundary is currently placed at 5 m.y. Thus, the 

Empire Formation is late Miocene. 

NW 

On the west side of the north-northeast-trending 

fault bounding the outer part of Cape Blanco, the sandstone of Floras Lake is not exposed. Instead, the N eogene strata that unconformably overlie Mesozoic sandstone and mudstone in the steep seacliffs at the cape 

are referable to the restricted Empire Formation. This 

massive concretionary marine sandstone (fig. 4) contains molluscan assemblages of late Miocene age that 

are referable to the Wishkahan Stage. Epifaunal 

marine macroinvertebrates, including Balanus and 

Chlamys, are abundant near the base (USGS loc. 

M3965). Stratigraphically higher beds contain infaunal bivalve assemblages; the venerid bivalve Securella is common (USGS loc. M4224). 

In the seacliff section southeast of Cape Blanco, the 

sandstone of Floras Lake grades from pebble and cobble conglomerate near the base to tuff and fine-grained 

micaceous sandstone near the top. Although the contact with the underlying Eocene shale and sandstone is 

concealed, the trend of this contact is un~onformable, 

as in the Blacklock Point-Floras Lake section a few 

kilometers to the north. The basal part of the unit is 

well exposed at Fin Rock (figs. 3, 5), where the lowest 

few meters consists of pebble- and cobble-conglomerate 

lenses and grayish-brown concretionary sandstone 

that has a knobby texture on weathered surfaces. The 

conglomerate lenses, as much as Y2 m thick, contain 

Unnamed Eocene mudstone I Sandstone of Floras Lake 

I--- and sandstone __ ___. • ..,..!------(lower part of Empire Formation of Diller, 1903) 

NW SE 

Detailed ~h section 

Scattered Balanus plates, Nucella packl and Mytllus fragments 

10 20 30 40 50 60 70 80 90 100 METERS 

I I I I I I I I I I 

FIGURE 3.-Seacliff section of sandstone of Floras Lake in an area about 1 to 1~ km southeast of lighthouse at Cape Blanco (see fig. 2 for 

Formation (upper Miocene); 
BIOSTRATIGRAPHY OF THE MARINE NEOGENE SEQUENCE, CAPE BLANCO, OREGON G5 

FIGURE 4.-Buff sandstone of the restricted Empire Formation unconformably overlying dark Mesozoic sandstone and mudstone (Dott, 

1962) at southwest tip of Cape Blanco. Height of small point is about 12m. View northwestward. 

SE 

Empire Formation (restricted) (upper part ____ -1 

of Empire Formation of Di,.:ll.:.e:..:r _1:...:9:...:0..:3.:.) _____ -l 

EXPlANATION 

- - - - - Approximate contact 

-? - -?- Concealed contact 

Unconformity I 

,.,.., USGS fossil locality (Menlo Park register) 

location). Mz, Mesozoic rocks; Te, Eocene rocks; Tsf, sandstone of Floras Lake (lower and middle Miocene); Tern, restricted Empire 

Q, Pleistocene terrace deposits. 
G6 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

barnacle plates and scattered individuals of the 

shallow-water gastropod Nucella. These strata grade 

upward into crossbedded sandstone containing scattered conglomerate lenses and carbonized-wood fragments that occur as lenses in beds which are locally 

crossbedded. The main fossiliferous localities are in 

concretionary beds in a 50- to 60-m interval below a 

tuff bed near the top of the formation (fig. 6). This 7- to 

8-m-thick tuff generally is poorly exposed; it is light 

gray, thin bedded, and pumiceous and contains scattered fQssil leaves (Wolfe and Hopkins, 1967). Above 

the tuff is 30m of massive carbonaceous and micaceous 

sandstone, containing scattered large flattened concretions. Minute specimens of articulated Spisula 

albaria (Conrad) are extremeley abundant in many of 

these concretions. 

The contact between the micaceous fine-grained 

sandstone of the uppermost part of the sandstone of 

Floras Lake and the unconformably overlying restricted Empire Formation is well exposed at the base 

of the seacliff about 1Yz km southeast of Cape Blanco 

(fig. 7). The unconformable surface has about 2 m of 

relief at beach level. The basal conglomerate of the 

restricted Empire Formation is almost 1 m thick; it 

consists principally of pebbles and boulders, as much 

as about 0.2 m in diameter. Larger flattened boulders, 

as much as 1 m in diameter, occur with regularity 

along the contact. The boulders are fossiliferous and 

contain poorly preserved bivalves that suggest a postNewportian age and are apparently penecontemporaneous. Some of the larger boulders are pitted with 

pholad burrows, as much as 5 em in diameter. A University of California collection purportedly from this 

conglomerate (UCMP Joe. A8710) is, in my opinion, a 

FIGURE 5.- Concretionary sandstone and pebble conglomerate of basal part of sandstone of Floras Lake exposed at low tide on Fin Rock, 

about 0.5 km east of Cape Blanco (see fig. 2 for location). 
BIOSTRATIGRAPHY OF THE MARINE NEOGENE SEQUENCE, CAPE BLANCO, OREGON G7 

stratigraphically mixed sample; most of the specimens 

are from the Coos Conglomerate Member and the 

Pactinopecten-bearingunit of the type Empire Formation at Coos Bay. There may also be some material from 

the restricted Empire Formation at Cape Blanco. 

The seacliff section of the restricted Empire Formation southeast of Cape Blanco consists of a 0.5-m-thick 

basal conglomerate, an overlying 35- to 40-m interval 

of concretionary medium-grained buff sandstone with 

scattered pebble-conglomerate lenses, and a 50- to 60-

m interval of white- to tan-weathering massive very 

fine grained sandstone and sandy siltstone. The sequence of units is conformable. The lowest 14 to 15m of 

the sandstone unit includes the basal pebble to cobble 

conglomerate containing large sandstone boulders. 

The conglomerate of lenses in the massive concretionary sandstone unit is fine grained and better sorted 

than the conglomerate in the lower part of the sandstone of Floras Lake. Vein quartz and chert clasts are 

very common in this conglomerate. Conspicuous concretionary beds in this interval contain abundant mollusks, notably the shallow-water bivalve Securella 

securis (Shumard) (USGS locs. M2140, M2141, M4124, 

M4125, M4133, M4134, M4225). The stratigraphically 

higher part of the basal sandstone unit is less fossiliferous and contains only scattered lenses of pebble conglomerate. The overlying massive sandy siltstone and 

very fine grained sandstone unit contains a 2-m-thick 

bed of fine- to medium-grained sandstone and a -mthick pebble bed some 20m above the base. The massive siltstone contains widely scattered molds of bivalve 

mollusks. Commonly occurring taxa are: Lucinoma 

annulata (Reeve), Macoma cf. M. calcarea (Gmelin), 

Nuculana sp., Portlandia sp., Compsomyax cf. C. subdiaphana (Carpenter), and Cnesterium scissurata 

(Dall) (USGS locs. M3755, M4223). 

Southeast of Cape Blanco, the restricted Empire 

Formation is unconformably overlain by poorly consolidated conglomerate and sandstone of the Port Orford 

Formation of Baldwin (1945). The angular unconformity between these formations (fig. 8) is well exposed 

in the seacliff southeast of the cape, in the vicinity of 

FIGURE 6.-Seacliff exposure of sa nd stone of Floras Lake about 1 km southeast of Cape Blanco. Massive gray and brown sandstone with 

scattered pebble-conglomerate lenses and concretionary beds in lower part of section, to left. in clude best fossiliferous localities in the 

unit (USGS locs. M2142. M4126, M4687). Conspicuous float from tuff bed is visible in grassy area midway up cl iff face at right edge of 

photograph. Miocene sandstone is unconformably capped by flat-lying fossiliferous stratum and fluvial gravel of late Pleistocene age at 

top of seac liff. View north-northwestward. 
G8 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

the beach-access road at the mouth of Goldwasher's 

Gully. 

PALEONTOLOGY OF THE SANDSTONE OF 

FLORAS LAKE 

INVERTEBRATE MACROFAUNA 

The molluscan fauna of the sandstone of Floras Lake 

consists of 30 identified molluscan taxa, including 6 

taxa identified only as to genus, an echinoid, and a 

barnacle (table 1). Plates 1 and 2 illustrate most of 

these macrofossils. Descriptions of the U.S. Geological 

Survey localities are listed in the Menlo Park, Calif., 

register of Cenozoic larger-invertebrate localities. 

PROVINCIAL AGE 

The molluscan fauna ofthe sandstone of Floras Lake 

is referable to the Newportian Stage (Addicott, 1976) 

of the Pacific Northwest Neogene molluscan province 

(fig. 9). Species that are restricted in stratigraphic 

occurrence to this stage and are also of fairly widespread distribution in rocks of this age in western 

Oregon and Washington include: Molopophorus matFIGURE 7.- Unconformable contact between Mytilus middendorffi-bearing sandstone of Floras Lake and the restricted Empire Formation 

in seacliff about ll';; km southeast of lighthouse at Cape Blanco (see fig. 2 for location). The Empire is unconformably overlain by late 

Pleistocene terrace deposits near top of 60-m-high seacliff. View northeastward. 
BIOSTRATIGRAPHY OF THE MARINE NEOGENE SEQUENCE, CAPE BLANCO, OREGON G9 

TABLE 1.-Mar-ine macr-o'inver-tebr-atesfr-om the sandstone of Flor-as Lake (lower part of the Empire Formation of Diller, 1903) exposed near 

Cape Blanco, Oregon 

lM number, U.S. Geological Survey, Menlo Park, Calif. , Cenozoic locality register, F number, University of Oregon, Eugene, locality. x, present as identified; cf., similar form; 

sp, species not determinable;?, doubtful identification] 

Species 

Gastropods: 

Bruc/arkia oregonensis (Conrad) (pL 

Cancfi/aria n, sp,? afL C alaskensis Clark (pL 

cL C ocoyana Addicott 

Crepidnla praerupta Conrad (pL 2, fig, 6) ,, 

rostra/is (Conrad) (pL L figs, 17, 18) 

C>,yptonat>'ca o>-egonensis (Conrad) (pL 2, fig, 17) 

Uracassis sp, (pL I, fig, 14) 

Megasnrc><la sp, (pL I, fig, 19),, 

Molopopho'f'US cf. M . unylununut; (Anderson) (pl. 

mattlwwi Etherington (pL 1, figs, 11, 21) 

Nat;t;u.riu;; anwldi Anderson (pl. 2, fig. 13) 

Natica cL N c{aTki Etherington (pL I, fig, 9) , 

Nucella sp, A (pL 1. fig, 22; pL 2, fig. 2) .. 

sp. B (pL 2, figs. 14, 15) , 

packi (Clark) (pL I, figs. I, 3-5, 13) 

Ophiodermel/a cL 0. ulympicensis Addicott (pL 1, figs. 25, 29) ,. 

Polin ices linculnensis (Weaver) (pl. 1, fig. 8) . 

Priscufusus cf. 1'. medialis (Conrad) (pl. I, fig. 10: pl. 2, fig. 11) 

Bivalves: 

Ka.tlwrinella. cf. K. angustifrons (Conrad) (pl. 2, figs. 3. 7) .. 

Macoma cf. M. flagleri Etherington (pl. 2. fig. 18) ... 

cf. M. secta (Conrad) (pl. 2. fig. 5) ... 

Mytilus middendmjfi Grewingk (pl. 2, figs. I, 4, 19) . 

Secure/la sp. (pl. 2, fig. 20) 

Solen conradi Dall (pl. I, fig. 24) 

Spisula a/bm·iu (Conrad) (pl. I, figs. 26, 28) 

cf. S. selbyertois Packard (pl. 2, fig. 21) .. 

Tell ina emacemta Conrad (pl. I. fig. 27; pl. 2, fig. 12) .. 

Yo/diu (Kalayuldia) cf. Y. (K.) carnero"nsis Clark (pl. I, fig. 23) 

aff. Y. coowri Gabb 

Scaphopod: 

Dentalium sp .. 

Ech inoid: 

Keu·ia cf. K. bla11coensis etheringtoni Weaver (pl. 2, fig. 9) . 

Barnacle: 

Balauus sp. 

thewi Etherington, Nassarius arnoldi (Anderson), 

Macoma jlagleri Etherington, and Mytilus middendorjji Grewingk. Other species have provincial stratigraphic r anges that extend from the older J uanian and 

(or) Pillarian Stages into the Newportian, or from the 

Newportian into the younger Wishkahan and (or) 

Graysian Stages (table 2). The cooccurrence of these 

species in the fossil record, then, is a further indication 

of a Newportian age. 

Correlative strata at Coos Bay, some 60 km to the 

north, yielded small assemblages from dredgings 

(Moore, 1963) and from a recently discovered 9-mthick section of sandstone on the east shore of Coos Bay 

(Baldwin, 1966; Armentrout, 1967, 1978) that contains 

typical Newportian mollusks. These Dosinia-rich collections contain a few specimens of the characteristic 

Newportian species Mytilus middendorjji Grewingk 

(USGS loc. 18284). 

Localities 

Southeast of Cape Blanco North of Black lock Point 

<- "' "' "' "' 0 ~ '"' 0 "' <- 00 "' ::l "' "' "' 0 ::l ~ ~ "' "' ;:::; ;;: ~ "' i "' " "" "' " ..,. :<: :<: :<: :<: :<: ~ :<: :<: :<: "' :<: 

-;-

sp. sp. sp. 

sp. 

cL cf. 

cL 

xp. sp. 

cf. 

cf. 

cf. cf. 

sp. 

CORRELATION 

The N ewportian fauna at Cape Blanco is of interprovincial chronostratigraphic significance in that it 

demonstrates the temporal equivalence of this Pacific 

Northwest time-stratigraphic unit with the "Temblor" 

Stage of central and southern California. Almost 80 

percent of the 23 specifically identified molluscan species in the Cape Blanco fauna occur in the fauna of the 

"Temblor" Stage, and many of these species are stratigraphically restricted to that stage (table 2). The much 

larger molluscan fauna from the type section of the 

Newportian Stage, about 200 km to the north, has only 

a small percentage of species in common with the 

"Temblor" Stage (Moore, 1963; Snavely and others, 

1964, p. 150), partly because of the presence of many 

endemic species in the Neogene molluscan province of 

the Pacific Northwest during the Miocene. 
G10 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

The occurrence of the distinctive plicate mussel 

Mytilus middendorjji Grewingk (pl. 2, figs. 1, 4, 19) in 

the sandstone of Floras Lake permits correlation of 

this unit with late Miocene and early middle Miocene 

deposits extending from southern California to the 

Gulf of Alaska (Allison and Addicott, 1976) and, possibly, Kamchatka (Pronina, 1969). 

PALEOECOLOGY 

Low-diversity assemblages of epifaunal invertebrates- Mytilus, Balanus, and Nucella- in the lower 

parts of the Blacklock Point and Cape Blanco sections 

indicate deposition in extremely shallow water close to 

a rocky shoreline. Moreover, lenses of pebble conglomerate characteristic of these basal strata appear to be 

homologous with the pebble gravel that occurs in the 

present-day surf-zone sediment of this area. In the 

Puget Sound area of northwestern Washington, 

Mytilus and Balanus form extensive beds in the lower 

reaches of the modern intertidal zone; dense accumuFIGURE 8.- Angular unconformity between massive silty sandstone 

and siltstone of the restricted Empire Formation and overlying 

conglomerate and sandstone of the Port Orford Formation of 

Baldwin (1945) in seacliff about 2 km southeast of lighthouse at 

Cape Blanco (see fig. 2 for location). Seacliff is about 60 m high. 

View northeastward. 

lations of these macroinvertebrates can, therefore, be 

taken as indicative of low-intertidal to high-subtidal 

environments. Living species of Nucella similar to 

those in the sandstone of Floras Lake prey on young 

mussels and, to a lesser extent, on barnacles (Paris, 

1960; Houston, 1971). The intimate association of 

Nucella with mussel beds in the intertidal zone along 

the east North Pacific coast has been noted by other 

workers (Smith and Gordon, 1948; McLean, 1969; 

Rice, 1971). This assemblage, then, suggests a rocky 

intertidal environment. The presence of these three 

invertebrates in pebble congomerate and pebbly sandstone indicates transportation in the surf zone, but 

their generally very good preservation indicates that 

the tests were not subjected to prolonged abrasion and 

that deposition may have been fairly rapid. 

Upsection, faunal diversity increases markedly, and 

infaunal bivalves and vagrant epifaunal forms become 

especially common. Nucella and Mytilus are present, 

but Sp·isula, Macoma, Bruclarkia, and naticoid gastropods characterize the middle to upper parts of the 

section southeast of Cape Blanco; faunal diversity 

increases northeast of Blacklock Point, though to a 

much lesser extent. This increase in diversity, together 

with the appearance of Katherinella, Liracassis, and 

Dentalium, indicates waters deepening to about 10 to 

European Provincial ! 

Time I 

(m.y.) 1::- Su--cb--.-------j 

sys - Series tern 

molluscan stage 

I 

Pliocene Moclipsian I 5 Graysian 

1----------< :l 

Formation 

1 II 

Empire Formation 

(restricted) 

"- 10 - Wishkahan 

~U IIIIIII I :s! "" 

1- 15-

1- 20-

" c 

.. ~ ~ 

~ 

f-- Newportian 

... f---- ------< j PUiarian 

Juanian 

,-

Sandstone ol' 

Floras Lake 

FIGURE 9.- Correlation of Neogene formations exposed at Cape 

Blanco, Oreg., with Pacific Northwest Territory molluscan 

chronology (Addicott. 1976). 

I 
BIOSTRATIGRAPHY OF THE MARINE NEOGENE SEQUENCE, CAPE BLANCO, OREGON Gil 

TABLE 2.-Provinc1:al stratigraphic range of species in the Cape 

Blanco Newportian fauna, with notes on their occurrence in the 

California Neogene molluscan province 

[Data principally from Loel and Corey. 1932; Moore. 1963; Addicott. 1970, 1972. 1973, 

1976; Marincovich. 1977] 

Species 

Brnclarkia o·rego1wnsis (Conrad) ... 

Cancellm·ia ocouana Addicott . 

Crrpidula prarmpta (Conrad) ... 

•·ostralis (Conrad) .. 

CnJptonatica orrgonensis (Conrad) ... 

Molopuphonu:: cf. M. anglonanu 

(Anderson ) ... 

mattheu:i Etherington . 

Nnssm·ius anwldi (Anderson) ... . 

Na.tica cf. N. clm·ki Etherington .. . 

N~<cellu pack i (Clark) ... 

0/ire/la cf. 0 . ischnon Keen 

Ophiodennella cf. 0. o/.IJ'tnpicnzsis 

Addicott .. 

Pacific Northwest 

molluscan stage 

t: t: "' "' " " -~ ..c: " .!! ·~ "' "' "' "" ""' ·;r. 

" ~ ~ -£ ,., 

"' "' " ..., Q: z ~ 0 

Occurrence in California 

Neogene mollusca n 

stages 

"Vaqueros" and "Temblor" 

"Temblor" 

-----"Vaqueros" and "Temblor" 

"Temblor" 

(not recorded in California 

Neogene) 

''Vaqueros" and "Temblor" 

(not recorded in California 

Neogene) 

"Temblor" 

(not recorded in California 

Neogene) 

"Vaqueros" and "Temblor" 

"Temblor" 

(not recorded in Ca lifornia 

Polinces tictoriunw; Clark and Arnold ... ---

Priscofusw; cf. F'. m.Pdialis (Conrad) 

Neogene) 

"Vaqueros" and "Temblor" 

"Vaqueros" and "Temblor" 

Katharinella angusti.from (Conrad) . "Temblo•·" 

Macoma cf. M. f/aglNi Etherington . 

cf. M. secta (Com·ad) 

Mytilus middendo>f!i Grewingk .. 

Solen con .-adi Dall 

Spisu/a a/b01·iu (Conrad) ... 

cf. S. se/b yensi., Packard .. 

Tel/ina rmacemla (Conrad) .. 

Yotd ia cf. Y. carnerosensis Clark 

(not r ecorded in California 

Neogene) 

--- "Vaqueros" to Holoce ne 

"Temblor" 

"Vaqueros" and "Temblor" 

----- Unnamed to "Etchcgoin" 

"Temblor" 

Unnamed to "Margaritan" 

"Temblor" a nd 

"Margaritan" 

20 m. A field identification of Patinopecten in the 

upper part of the Blacklock Point section supports this 

depth. 

The stratigraphically highest beds of the sandstone 

of Floras Lake exposed southeast of Cape Blanco 

(USGS Joe. M4135) contain an assemblage of minute 

articulated specimens of Spisula and scattered Dentalium. The rocks are highly micaceous, an indicator of 

relatively quiet and possibly deeper water conditions 

than those present when stratigraphically lower units 

in the sandstone of Floras Lake were laid down. Mica 

does not occur in appreciable amounts in modern sediment of the California coast in waters shallower than 

about 10 to 20m; however, it is highly concentrated at 

depths greater than 35 to 40 m (Galliher, 1932). 

The succession of marine macroinvertebrate communities preserved in the 150- to 180-m-thick early 

and middle Miocene section southeast of Cape Blanco 

indicates deposition in the inner sublittoral zone but 

suggests some progressive deepening as deposition 

progressed. The occurren~e of fossil leaves (Wolfe and 

Hopkins, 1967, p. 70- 71) in a 5- to 10-m-thick thinbedded locally cross-stratified tuff bed near the top of 

the formation may indicate a brief reversal of this 

deepening trend. According to J. A. Wolfe (written 

commun., 1977), the taxonomic composition of the florule and fragmentation of the leaf specimens indicate 

transportation in a high-energy environment. No 

marine mollusks were found with the fossil leaves. 

The taxonomic predominance of gastropods over 

bivalves suggests an open-coast depositional environment rather than the protected-bay environment typified by many of the bivalve-dominated assemblages 

from the middle and late Miocene of northern California (Clark, 1915; Hall, 1958). This relation was first 

observed by Packard (1918) in the modern levelbottom faunal assemblages of San Francisco Bay and 

the adjacent open-coastal area of northern California. 

Probably the most significant paleoecologic aspect 

of the macrofauna in the sandstone of Floras Lake is its 

deposition in unusually shallow water. Assemblages 

from the lowest part of the unit are of markedly shallower water aspect than any of the well-known assemblages (Moore, 1963) of theN ewportian Stage farther 

north along the Oregon and Washington coast (from 

Coos Bay to the mouth of the Columbia River). The 

characteristic faunal elements of the sandstone of Floras Lake-Mytilus, Balanus, and Nucella- occur 

exceedingly rarely in assemblages from the coeval 

Astoria Formation. These genera occur in only three of 

the more than 200 collections listed by Moore (1963, 

table 2). Moreover, the presumably shallow water 

echinoid Kew1:a (USGS locs. M4125, M4690) is not 

reported from any locality in the Astoria Formation of 

Oregon. 

PALEONTOLOGY OF THE RESTRICTED 

EMPIRE FORMATION 

The restricted Empire Formation (upper part of the 

Empire Formation of Diller, 1903) contains mollusks 

of late Miocene age referable to the Wishkahan Stage 

(pl. 3;. table 3). Southeast of Cape Blanco, where the 

formation unconformably overlies the sandstone of 

Floras Lake, these mollusks occur in the lower 30m of 

the restricted Empire (fig. 10). Mollusks observed in 

and collected from the basal conglomerate (loc. M7378) 

include: Chlamys sp., Securella secur1:s (Shumard), 

Yoldia Kalayoldia) sp., Spisula sp., Saxidomus g1:ganteus (Deshayes), Cryptonatica sp., and Olivella sp. The 

previously noted mixed collection of mollusks (UCMP 

Joe. A8710) that is allegedly from this conglomerate 

contains specimens of Crepidula princeps (Conrad), 
G12 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

Securella securis (Shumard), Macoma spp., Pseudocardium sp., and other mollusks that are identical in 

preservation to material from the Coos Conglomerate 

Member of the Empire Formation at Coos Bay, 60 km 

north. They have the characteristic yellow coarsegrained sandstone matrix and show signs of transportation before ultimate deposition. The Patinopecten 

coosens1:s (Shumard) specimens in this collection presumably are from the rocks exposed at Pecten Point in 

the lower part of the type section of the Empire Formation at Coos Bay. The mixing can be explained by the 

fact that this material was collected by a student group 

that visited all the localities in question during a brief 

field trip in 1952; the presumption is that inadequate 

notes may have been kept with the samples and that 

mixing occurred as a result. Very poorly preserved 

sand-dollar echinoids in this collection that seem to be 

Scutellasteroregonensis (Clark) may be from the Empire 

section at Coos Bay rather than from Cape Blanco. 

At Cape Blanco, where the Empire unconformably 

overlies pebbly mudstone of Mesozoic age (Dott, 1962), 

the Empire is bounded on the eastside of the Cape by a 

FIGURE 10.-Unconformable contact between bedded micaceous sandstone of Floras Lake and massive concretionary sandstone of the 

restricted Empire Formation exposed in seacliff southeast of Cape Blanco. 
BIOSTRATIGRAPHY OF THE MARINE NEOGENE SEQUENCE, CAPE BLANCO, OREGON G13 

TABLE 3.-Late Miocene (Wishkahan) macroinvertebratesf,.om the lo·wer part of the restricted Empire Formation near Cape Blanco, Oregon. 

[M number, U.S. Geological Survey, Menlo Park, Calif.. Cenozoic locality register; x, present as identified; cf .. similar form; ?, doubtful identification; g, genera only] 

Species 

Gastropods: 

Annaea sp 

Calliostoma cammani DalL 

Crepidulu adunca Sowerby .. 

cf. C. princeps Conrad .. 

cf. C. ony.r Sower by . 

Cryptonatica cf. C. clau.~a (Broderip and Sowerby) .. 

Diodora sp . 

Liomesu~ ~ulcatus Dall 

Littorina petricola Dall .. 

Mediargo sp . 

Molopoplwrus bogachieli (Reagan). 

Nassarius andersoni (Weaver) .. 

lwquiamensis Addicott 

Neptunea lyrata (Gmelin) .. 

Nucella canaliculata (Duclos) .. 

etchegoinen~i~ (Arnold) 

lima (Gmelin) 

Ocenebra sp 

Olicella sp 

Opalia 1cishkahcnsis Durham .. 

Polinieessp .. 

Troch ita n. sp. Moore 

Trophonopsis cf. T. stuarti (Smith) . 

sp .. 

Bivalves: 

Acila blancoensis Howe .. 

Anwlara trilincata (Conrad) . 

Area sp .. 

Chlamys hodgei (Hertlein) 

sp .. 

Clinocardium mef'kianum (Gabb). 

Cnesterium aff. C. scissura/a (Dall). 

Felanie/la pari/is (Conrad) . 

Glycymeris gre1cingki Dall 

Lucinoma cf. L. acutilineata (Conrad) . 

Macoma indentata Carpenter .. 

secta (Conrad) .. 

Mi:::uhopecten n. sp 

Modiolus sp .. 

Pandora sp . 

Securella sec uris (Shumard) . 

Sa.tidomus giganteus (Deshayes) 

Siliqua cf. S. Iucida (Conrad) . 

Spisula cf. S. alba ria coo.~en.~is Howe .. 

praecursor Dall 

Tel/ina aragonia Dall . 

cf. T. bodegensi~ Hinds 

Tellinel/a merriami (Weaver) .. 

Tresw; pajaroanus (Conrad) . 

Yoldia cooperi Gab b. 

Echinoid: 

Keu•ia blancoensis (Kew) ... 

Barnacle: 

Balanus tintinnabulum coosensis Dall . 

Tn·ebratalia tnliiSI'er~a caurina Gould 

north-northeast-trending fault that juxtaposes therestricted Empire Formation containing Wishkahan 

assemblages on the west side against middle Eocene 

marine strata on the east side (Dott, 1971, fig. 34). The 

basal Miocene strata on the east side of the fault that 

unconformably overlie the Eocene strata consist of 

poorly fossiliferous sandstone and conglomerate of 

early and middle Miocene age; these strata are referable 

to the N ewportian Stage. 

cf. 

d g 

cf. cf. 

cf. 

cf. cf. 

cf. 

cf. cf. 

g g 

cf. cf. cf. 

cf. g 

cf. 

rf. 

g 

cf. 

g 

g 

Table 3lists mollusks collected from the basal part of 

the restricted Empire Formation. Species from therestricted Empire that occur only in the Wishkahan Stage 

include: Acila blancoens'is Howe, Glycyrner?·s grewingki 

Dall [=G. gabbi Dall], TeZZ.inella rnerriami (Weaver), 

and Opal ia w1'shkahensis Durham. Many other species 

appear in the Wishkahan Stage but range into younger 

strata: Nassarius cf. N. anderson1~ (Weaver), Nucella 

canaliculata. (Duclos), Molopophorus bogach£eli (Rea-
G14 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

gan), Clinocardiurn meekianurn (Gabb), and Securella 

securis (Shumard). The close identity with the much 

larger fauna of the type section of the Empire Formation at Coos Bay suggests that these two units are 

coeval. The greater diversity of the type Empire fauna 

may result from the much broader area of exposure in 

addition to the concentration of reworked fossils in the 

intraformational Coos Conglomerate Member. Another 

factor is the apparently greater depth of deposition of 

the type Empire Formation, as judged by the common 

occurrence of the bivalve Pat'l~nopecten and the gastropod Neptunea in sandstone that underlies the Coos 

Conglomerate Member; neither genus is known from 

the Cape Blanco exposures. The Empire Formation at 

Coos Bay was long considered to be Pliocene (Diller, 

1986; Howe, 1922; Weaver, 1945), but recalibration of 

the provincial molluscan chronology with European 

standards (Addicott, 1976) has raised the MiocenePliocene boundary such that the formation here is now 

assigned a late Miocene age. 

Scattered bivalves in the massive sandy siltstone 

and very fine grained sandstone of the upper part of 

the restricted Empire Formation (see list on p. 7) constitute a low-diversity assemblage of poorly preserved 

mollusks that is not diagnostic of provincial age and 

correlation. Siliceous microfossils that occur with 

these mollusks, however, indicate a late late Miocene 

age. Correlation of the diatom florule with florules in 

the upper part of the Montesano Formation of Weaver 

(1912) of southwestern Washington (J. A. Barron, oral 

commun., 1977) suggests that the molluscan assemblage may be referable to the Graysian Stage. The 

assemblage from U.S. Geological Survey microfossil 

locality Mf3943 (=M3755) includes the diatoms Actinoptychus m'z:nutus Greville, A. vulgarz:s var. monicae 

Grunow, Coscinodiscus lineatus var. leptopus Grunow, 

C. temperi Brun, Denhcula hustedtii Simonsen and 

Kanaya, Lithodesm 'l:urn californicum Grunow, Nitzschia 

praereinhold,ii Schrader, Roux,ia ca,lijorn'l:ca Peragallo, Stephanopyx'l:s schenckii Kanaya, and Thalassiosira lineataJouse. Also recorded from locality Mf3943 

are the silicoflagellates D1:stephanus speculurn var. 

pseudocrux Schulz and D. pseudojibula (Schulz) Bukry. 

J. A. Barron (oral commun., 1979) correlated this assemblage with North Pacific Diatom Zone 11 and 

assigned it to the late Miocene, noting that benthic 

foraminifers of the upper part of the Mohnian Stage 

occur in this zone in southern California. 

The restricted Empire Formation is unconformably 

overlain by the conglomerate and sandstone of the Port 

Orford Formation of Baldwin (1945), the lower part of 

which contains early Pleistocene molluscan assemblages composed entirely of living species. The inner, 

sublittoral fauna of this formation has long been of 

interest to malacologists (Arnold and Hannibal, 1913, 

p. 595-597; Martin, 1916, p. 245-24 7; Smith, 1919, p. 

138; Hertlein and Crickmay, 1925, p. 275-276; Zullo, 

1961; Allison and others, 1962). The molluscan and 

echinoid fauna of the Port Orford was the subject of 

doctoral research by Barry Roth at the University of 

California, Berkeley (Roth, 1979). 

The basal part of the Port Orford, the "Gold washer's 

Gully member" (R. J. Janda, written commun., 1978), 

consists of buff sandstone and thin pebble-conglomerate beds, exposed at Goldwasher's Gully (fig. 11). This 

unit contains scattered burrows and molds of invertebrates that suggest a marine origin. The unit is truncated by a 7- to 8-m-thick conglomerate that is regarded 

by sedimentologists as fluvial in origin (R. J. Janda, 

oral commun., 1979). The conglomerate oversteps the 

so-called Goldwasher's Gully member of the Port 

Orford Formation to lie unconformably on the Empire 

Formation west of Goldwasher's Gully (fig. 11). The 

conglomerate forms the basal part of the Elk River 

Formation, a unit containing exceptionally rich deposits of bivalves in its upper part. Excellent exposures of 

these fossiliferous beds occur a few meters stratigraphically above a conspicuous bluish-gray massive silty 

sandstone containing scattered concretions with Katherinella and Pactinopecten caur,inus (Gould). These 

deposits are informally known as the Psephidia beds, 

owing to the dense accumulation of this small bivalve 

(see Clifton and Boggs, 1970). The beds are best exposed 

in seacliffs about 2Y2 km southeast of Goldwasher's 

Gully (fig. 12). 

AGE AND PROVENANCE OF SCUTELLA BLANCOENSJS KEW 

Contradictory statements as to the geologic age and 

stratigraphic occurrence of the type specimens of Scutella [Kewia] blancoensis Kew have left the chronostratigraphic status of this species in doubt. The species 

has been considered to be as old as Oligocene (Kew, 

1920) and as young as Pliocene (Weaver, 1942). Recent 

mapping (Dott, 1962; R. J. Janda, unpub. data, 1978) 

and biostratigraphic studies on the stratigraphic 

occurrence of this taxon strongly suggest that it is of 

provincial early late Miocene age and referable to the 

Wishkahan Stage. 

The type specimens of Scutella blancoens,is Kew 

(1920, p. 64-65, pl. 11, figs. 1a-1c) are from two localities near Cape Blanco (Stanford Univ.loc. NP26, California Acad. Sci. loc. 17). Both these localities are in 

strata southeast of Cape Blanco of possible late Miocene age that may be coeval with the type Empire 

Formation of the Coos Bay area. Kew's (1920, p. 65) 

statement that the types are from "Basal sandstone, 

sea cliffs north of lighthouse, Cape Blanco" seems to be 
BIOSTRATIGRAPHY OF THE MARINE NEOGENE SEQUENCE, CAPE BLANCO, OREGON G15 

in error because Stanford University locality NP26 is 

described as "basal sandstone, seacliffs southeast of 

lighthouse for a mile along shore" (Arnold and Hannibal, 1913, p. 591), and California Academy of Sciences 

locality 17 is from seacliffs about 2 to 2Y2 km southeast 

of Cape Blanco. If either or both of these specimens 

were actually collected from the north side of Cape 

Blanco, a late Miocene age is clearly indicated; the 

associated molluscan fauna (USGS locs. M3965, 

M4224) in the basal part of the restricted Empire 

Formation that encircles the cape and unconformably 

overlies Mesozoic strata (Dott, 1962, pl. 2) includes 

species referable to the Wishkahan Stage, the early 

part of the provincial late Miocene. 

A fossiliferous float block found above high-tide 

level on the beach southeast of Cape Blanco directly 

below ledge-forming fossiliferous sandstone of therestricted Empire Formation yielded many specimens of 

Scutella blancoens1:s. This block contained mollusks 

diagnostic of the Wishkahan Stage (early late Miocene); 1 

there is little doubt that it broke off from one of the thin 

ledges of fossiliferous calcareous sandstone on the 

near-vertical cliffs forming the basal part of the restricted Empire Formation in this area. Several late 

Miocene mollusks also were recovered from this block 

(USGS loc. M2141). The echinoid is characterized by 

extremely fine tubercules on the aboral surface and an 

anteriorly eccentric apical system. Similar specimens 

from the underlying late early or middle Miocene 

Mytilus middendorjfi beds (pl. 2, fig. 9) have fewer and 

much larger tubercules; these specimens seem to 

represent the small early or middle Miocene subspecies 

Kewia blancoensis etheringtoni (Weaver, 1942) from 

the Astoria Formation of southwestern Washington. 

Presumably, Durham's (1953) record of K. blancoensis 

from the Mytilus middendorffi beds southeast of Cape 

Blanco is of this pre-late Miocene subspecies. His later 

record from the middle Miocene (Durham, 1953, fig. 

34d) is from Stanford University collection NP26, a 

stratigraphically mixed collection from both the sandstone of Floras Lake and the restricted Empire Formation . A later collection in the University of California Museum of Paleontology (UCMP colin. B7511) 

containing K. blancoensis is not from the sandstone of 

Floras Lake. The specimen in question occurs in a 

waterworn sandstone boulder that contains mollusks 

indicative of a Wishkahan (late Miocene) age: Molopophorus bogachieli (Reagan), Siliqua sp., a large coarseribbed specimen of Clinocardium, and fragments of a 

large concentrically sculptured Tellina. This assemblage indicates derivation from the lower part of the 

restricted Empire Formation. 

The small echinoids with fine tubercules from the 

restricted Empire Formation are believed to be Kewia 

FIGURE 11.-Unconformable contact between the upper Miocene restricted Empire Formation and the overlying lower Pleistocene Port 

Orford Formation of Baldwin (1945) exposed immediately west of Gold washer's Gully (left center of photograph). Conglomerate and 

sandstone of the Port Orford contrast sharply with underlying massive white diatomaceous siltstone and silty sandstone of the restricted 

Empire Formation. Angular unconformity between conglomerate and sandstone unit of the Port Orford ("Goldwasher's Gully 

member"; R. J. Janda, written commun., 1978) and overlying 7· to 8-m-thick fluvial conglomerate that marks base of the Elk River 

Formation is apparent to east of Gold washer's Gully. View northwestward. 
G16 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

blancoensis (Howe) s.s. Those from the underlying 

sandstone of Floras Lake, which differ by having relatively coarse tubercules, may represent a closely related subspecies, K. blancoensis ethen:ngtoni (Weaver). 

FIGURE 12.-Psephidia beds in upper part of the Port Orford Formation of Baldwin (1945) exposed near mouth of Elk River, 

about 2Y:, km southeast of Gold washer's Gully. 

REFERENCES CITED 

Addicott, W. 0., 1964, A late Pleistocene invertebrate fauna from 

southeastern Oregon: Journal of Paleontology, v. 38, no. 4. p. 

650-661. 

__ 1970, Miocene gastropods and biostratigraphy of the Kern 

River area, California: U.S. Geological Survey Professional 

Paper 642, 174 p. 

__ 1972, Provincial middle and late Tertiary molluscan stages, 

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p. 1-26. 

__ 1973, Oligocene molluscan biostratigraphy and paleontology 

of the lower part of the type Temblor Formation, California: 

U.S. Geological Survey Professional Paper 791, 48 p. 

_ _ 1976. Neogene molluscan stages of Oregon and Washington, 

in Fritsche, A. E., Ter Best, Harry, Jr., and Wornardt, W. W., 

eds., The Neogene Symposium: Los Angeles, Society of Economic Paleontologists and Mineralogists, Pacific Section, p. 

95-115. 

__ 1977, Neogene chronostratigraphy of nearshore marine basins of the eastern North Pacific: Northwestern Mexico to Canada: International Congress of Pacific Neogene Stratigraphy, 

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__ 1980, Miocene stratigraphy and fossils, Cape Blanco, Oregon: 

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Allison, E. C., Durham, J. W., and Zullo, V. A., 1962, Cold-water late 

Cenozoic faunas of northern California and Oregon [abs.], in 

Abstracts for 1961: Geological Society of America Special 

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Allison, R. C., and Addicott, W. 0., 1976, The North Pacific Miocene 

record of Mytilus (Plicatomytilus), a new subgenus of Bivalvia: 

U. S. Geological Survey Professional Paper 962, 21 p. 

Armentrout, J. M., 1967, The Thrheel and Empire Formations, geology and paleontology of the type sections, Coos Bay, Oregon: 

Eugene, University of Oregon, M.S. thesis, 154 p. 

__ 1978, A new Miocene formation at Cods [Coos] Bay, Oregon: 

American Association of Petroleum Geologists- Society of 

Economic Geophysicists-Society of Economic Paleontologists 

and Mineralogists, Pacific Section Annual Meeting, 53d, Sacramento, Calif., 1978, Program, p. 12-13. 

Arnold, Ralph , and Hannibal, Harold, 1913, The marine Tertiary 

stratigraphy of the north pacific Coast of America: American 

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Baldwin, E. M., 1945, Some revisions of the late Cenozoic stratigraphy of the southern Oregon coast: Journal of Geology, v. 53, 

no. 1, p. 35-46. 

__ 1966, Some revisions of the geology of the Coos Bay area, 

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Bandy, 0. L., 1944, Eocene foraminifera from Cape Blanco, Oregon: 

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__ 1950, Some later Cenozoic Foraminifera from Cape Blanco, 

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(Psephidia) shells in shallow marine sand, Elk River beds, 

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Dall, W. H .. 1909, Contributions to the Tertiary paleontology of the 

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Diller, J. S., 1896, A geological reconnaissance in northwestern 

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441- 520. 

__ 1899, The Coos Bay coal field, Oregon: U.S. Geological Survey 

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_ _ 1902, Topographic development of the Klamath Mountains 

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69 p. 

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6 p. 

Dott, R. H., Jr., 1962, Geology of the Cape Blanco area, southwest 

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__ 1971, Geology of the southwestern Oregon coast west of the 

124th meridian: Oregon Department of Geology and Mineral 

Industries Bulletin 69, 63 p. 
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Durham, J. W., 1953, Miocene at Cape Blanco, Oregon [abs.]: Geological Society of America Bulletin, v. 64, no. 12, pt. 2, p. 1504-1505. 

Galliher, E. W., 1932, Sediments of Monterey Bay, California: California Division of Mines, State Mineralogist Report 28, v. 28, 

no. 1, p. 42-79. 

Hall, C. A., Jr., 1958, Geology and paleontology of the Pleasanton 

area, Alameda and Contra Costa County, California: University 

of California Publications in Geological Sciences, v. 34, no. 1, p. 

1-90. 

Hertlein, L. G., and Crickmay, C. H., 1925, A summary of the 

nomenclature and stratigraphy of the marine Tertiary of Oregon 

and Washington: American Philosophical Society Proceedings, 

v. 64, no. 2,p. 224-282. 

Houston, R. S., 1971, Reproductive biology of Thais emarginata 

(Deshayes, 1839)and Thaiscanaliculata (Duclos, 1832): Veliger, 

v. 13,no. 4,p. 348-357. 

Howe, H. V., 1922, Faunal and stratigraphic relationships of the 

Empire Formation, Coos Bay, Oregon: University of California 

Publications, Department of Geological Sciences Bulletin, v. 14, 

no. 3. p. 85-114. 

Kennedy, G. L., 1978, Pleistocene paleoecology, zoogeography and 

geochronology of marine invertebrate faunas of the Pacific 

Northwest coast (San Francisco Bay to Puget Sound): Davis, 

University of California, Ph.D. dissertation, 824 p. 

Kew, W. S. W., 1920, Cretaceous and Cenozoic Echinoida of the 

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Loel, Wayne, and Corey, W. H., 1932, The Vaqueros formation, Lower 

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no. 3, p. 31-140. 

Marincovich, Louie, Jr., 1977, Cenozoic Naticidae (Mollusca: Gastropoda) of the northeastern Pacific: Bulletins of American 

Paleontology, v. 70, no. 294, 494 p. 

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McLean, J. H., 1969, Marine shells of southern California: Los 

Angeles County Museum Science Series 24, Zoology no. 11, 104 p. 

Moore, E. J., 1963, Miocene marine mollusks from the Astoria Formation in Oregon: U.S. Geological Survey Professional Paper 

419, 109 p. 

Newberry, J. S., 1856, Report upon the geology of the route [Williamson's survey in California and Oregon]: U.S. Pacific Railroad 

Exploration Reports (U.S. 33d Cong., 2d sess .. Senate Ex. Doc. 

78 and H. Doc. 91), v. 6, pt. 2, p. 5-68. 

Packard,E. L., 1918, A quantitative analysis of the molluscan fauna 

of San Francisco Bay: University of California Publications in 

Zoology, v. 19, no. 13, p. 299-336. 

Paris, 0. H., 1960, Some quantitative aspects of predation by 

muricid snails on mussels in Washington Sound [Washington]: 

Veliger, v. 2, no. 3, p. 41-47. 

Pronina, I. G., 1969, Mollyuski sredemiotsenovyikh otlozheniy Kronotskogo raiona vostochnogo poberezh'ya Kamchatka [Mollusks 

of middle Miocene deposits of the Kronotskiy region of the eastern shoreline of Kamchatka]: Moscow, Vsesoyuznogo Neftyanogo N auchno-Issledovatel'skogo Geologo-Razvedochnogo Instituta Trudy, Paleontologicheskiy Sbornik 4, vyp. 268, p. 244-261, 

pls. 1-4. 

Rice, Tom, 1971, Marine shells of the Pacific Northwest: Edmonds, 

Wash., Ellison Industries, 102 p. 

Roth, Barry, 1979, Late Cenozoic marine invertebrates from northwestern California and southwestern Oregon: Berkeley, University of California, Ph. D. thesis, 803 p. 

Schenck, H. G., 1928, Stratigraphic relations of western Oregon 

Oligocene formations: University of California Publications, 

Department of Geological Sciences Bulletin, v. 18, no. 1, p. 1-50. 

___ 1936, Nuculid bivalves of the genus Acila: Geological Society 

of American Special Paper 4, 149 p. 

Smith, A. G., and Gordon, M., Jr., 1948, The marine mollusks and 

brachiopods of Monterey Bay, California, and vicinity: California Academy of Sciences Proceedings, ser. 4, v. 26, no. 8, p. 

147-245. 

Smith, J.P., 1919, Climatic relations of the Tertiary and Quaternary 

faunas of the California region: California Academy of Sciences 

Proceedings, ser. 4, v. 9, no. 4, p. 123-173, pl. 9. 

Snavely, P. D., Jr., Rau, W. W., and Wagner, H. C., 1964, Miocene 

stratigraphy of the Yaquina Bay area, Newport, Oregon: Ore 

Bin. v. 26, no. 8,p. 133-151. 

Weaver, C. E., 1912, A preliminary report on the Tertiary paleontology of western Washington: Washington Geological Survey Bulletin 15, 80 p. 

___ 1942, Paleontology of the marine Tertiary formations of 

Oregon and Washington: Seattle, University of Washington 

Publications in Geology, v. 5. no. 1-3, 789 p. 

__ 1945, Stratigraphy and paleontology of the Tertiary formations at Coos Bay, Oregon: Seattle, University of Washington 

Publications in Geology, v. 6, p. 31-62. 

Wolfe, J. A .. and Hopkins, D. M., 1967, Climatic change recorded by 

Tertiary land floras in northwestern North America, in Hatai. 

Kotora. ed., Tertiary correlations and climatic changes in the 

Pacific: Sendai, Japan. Sasaki, p. 67-76. 

Zullo, V. A., 1961. "Pliocene" of northern California and southern 

Oregon [abs.], in Current research in the geological sciences: 

Los Angeles, University of California, Department of Geology 

graduate symposium, p. 8. 

A 

Acila blancoensis, 13; pl. 3 

conradi, 3 

Acmaea sp., 13 

Actinoptychus minutus, 14 

vulgaris monicae, 14 

acutilineata, Lucinoma, 13 

adunca, Crepidula, 13; pl. 3 

alaskensis, Cancellaria, 9; pis. 1, 2 

albaria coosensis, Spisula, 13 

Spisula,6,9, 11;pl.1 

Anadara trilineata, 13 

andersoni, Nassarius, 13; pl. 3 

anglonana, Molopophorus, 11 

anglonanus, Molopophorus, 9; pl. 1 

angustifrons, Katherinella, 9, 11; pl. 2 

annulata, Lucinoma, 7 

aragonia, Tellina, 13 

Area sp., 13 

arnoldi, Nassarius, 3, 9, 11; pl. 2 

Astoria Formation, 2, 11 

B 

Balanus, 3, 4, 10, 11 

tintinnabulum coosensis, 13 

sp., 9 

Blacklock Point, 2. 3, 9, 10, 11 

blancoensis etheringtoni,Kewia, 9, 15. 16; pl. 2 

Acila, 13; pl. 3 

Kewia, 13, 15; pl. 3 

Scutella, 2. 3, 14, 15 

Scutella (Kewia), 14 

bodegensis, Tel/ina, 13 

bogachieli.Molopophorus, 13, 15; pl. 3 

Bruclarkia, 10 

oregonensis, 9, 11; pl. 1 

(Bruclarkia) stanfordensis, Fusus, 3 

c 

calcarea,Macoma, 7 

californica, Rouxia, 14 

californicum, Lithodesmium, 14 

Calliostoma cammani, 3, 13; pl. 3 

cammani, Calliostoma, 3, 13; pl. 3 

canaliculata, Nucella, 13 

Cancellaria alaskensis, 9; pis. 1, 2 

ocoyana, 9, 11 

oregonensis, 3 

n. sp., 9; pis. 1, 2 

Cardium ( Clinocardium) meekianum, 3 

carnerosensis, Yoldia, 11; pl. 1 

Yoldia (Kalayoldia), 9 

caurina, Terebratalia transversa, 13 

caurinus, Patinopecten, 14 

Chlamys, 4 

hodgei, 13; pl. 3 

sp.,11;pl.3 

Clallam Formation, 2 

clarki, Natica, 9, 11; pl. 1 

clausa, Cryptonatica, 13 

Clinocardium, 15 

meekianum 13; pl. 3 

( Clinocardium) meekianum, Cardium, 3 

Cnesterium scissurata, 7, 13 

Compsomyax subdiaphana, 7 

conradi, Acila, 3 

Solen,9, 11;pl.1 

INDEX 

[Italic page numbers indicate major reference] 

cooperi, Yoldia, 9, 13 

CoosBay, 1, 12 

Coos Conglomerate Member, 7, 12, 14 

coosensis, Balanus tintinnabulum, 13 

Patinopecten, 12 

Spisula albaria, 13 

Coscinodiscus lineatus leptopus, 14 

temperi, 14 

Crepidula adunca, 13; pl. 3 

onyx, 13 

praerupta, 9, 11; pl. 2 

princeps, 11, 13 

rostralis, 9, 11; pl. 1 

Cryptonati.ca clausa, 13 

oregonensis, 9, 11; pl. 2 

sp., 11 

D,E 

Dentalium, 10, 11 

hustedtii, 14 

sp., 9 

Diodora sp., 13 

Distephanus pseudo{ibula, 14 

speculum pseudocrux, 14 

Dosinia, 9 

emacerata, Tellina, 9, 11; pis. 1. 2 

Empire Formation, 1, 2, 4, 7, 12, 13, 14 

restricted, 11 

etchegoinensis, Nucella, 13 

etheringtom:, Kewia blancoensis, 9, 15, 16; pl. 2 

F,G 

Felaniellaparilis, 13; pl. 3 

Fin Rock, 4, 13 

flagleri,Macoma, 9, 11; pl.2 

Floras Lake, 2, 3 

Fusus (Bruclarkia) stanfordensis, 3 

gabbi, Glycymeris, 13 

giganteus, Saxidomus, 11, 13 

Glycymeris gabbi, 13 

grewingki, 13; pl. 3 

Goldwasher's Gully, 8, 13, 14 

Graysian Stage, 9 

grewingki, Glycymeris, 13; pl. 3 

H, I, J 

hodgei, Chlamys, 13; pl. 3 

hoquiamensis, Nassarius, 13 

Hunters Cove Formation, 3 

hustedtii, Denticula, 14 

indentata,Macoma, 13 

ischnon, Olivella, 9, 11; pl. 2 

Juanian Stage, 9 

(Kalayoldia) carnerosensis, Y oidia, 9 

sp., Y oidia, 11 

Katherinella, 10, 13 

angustifrons, 9, 11; pl. 2 

Kewia, 11 

blancoensis, 13, 15; pl. 3 

etheringtoni, 9, 15, 16; pl. 2 

(Kewia) blancoensis, Scutella, 14 

L 

leptopus, Coscinodiscus lineatus, 14 

lima,Nucella, 13, pl. 3 

lincolnensis, Polinices, 9; pl. 1 

lineata, Thalassiosira, 14 

lineatus leptopus, Coscinodiscus, 14 

Liomesus sulcatus, 13 

Liracassis, 10 

sp., 9; pl. 1 

Lithodesmium californicum, 14 

Littorina petri cola, 13 

Iucida, Siliqua, 13; pl. 3 

Lucinoma acutilineata, 13 

annulata, 7 

lyrata, Neptunea, 13 

M 

Macoma, 10 

calcarea, 7 

flagleri, 9, 11; pl. 2 

indentata, 13 

secta, 9, 13; pl. 2 

spp., 12 

matthewi,Molopophorus, 8, 9, 11; pl. 1 

medialis, Priscofusus, 9, 11; pis. 1, 2 

Mediargo sp., 13 

meekianum, Cardium ( Clinocardium), 3 

Clinocardium, 13; pl. 3 

Megasurcula sp., 9; pl. 1 

merriami, Tellinella, 13 

middendor{{i, Mytilus, 3, 9, 10, 11, 15; pl. 2 

minutus, Actinoptychus, 14 

Mizuhopecten n. sp., 13 

Modiolus sp., 13 

Mohnian Stage, 14 

Molopophorus anglonana, 11 

anglonanus, 9; pl. 1 

bogachieli, 13, 15; pl. 3 

matthewi, 8, 9, 11; pl. 1 

sp., 3 

monicae, Actinoptychus vulgaris, 14 

Montesano Formation, 14 

Mytilus, 10, 11 

middendor{{i, 3, 9, 10, 11, 15; pl. 2 

N 

Nassarius andersoni, 13; pl. 3 

arnoldi, 3, 9, 11; pl. 2 

hoquiamensis, 13 

Natica clarki, 9, 11; pl. 1 

N eptunea, 13 

lyrata, 13 

Newportian fauna, 11 

Newportian Stage, 2, 3, 8, 9 

Nitzschia praereinholdii, 14 

North Pacific Diatom Zone 11, 14 

Nucella, 6, 10, 11 

canaliculata, 13 

etchegoinensis, 13 

lima, 13; pl. 3 

packi, 3, 9, 11; pl. 1 

n. sp. A, pis. 1, 2 

n. sp. B, pl. 2 

sp. A, 9 

sp. B, 9 

Nuculana sp., 7 

0 

Ocenebra sp., 13 

G19 
G20 

ocoyana, Cancellaria, 9, 11 

Olivella ischnon, 9, 11; pl. 2 

sp., 11,13 

olympicensis, Ophiodermella, 9, 11; pl. 1 

onyx, Crepidula, 13 

Opalia wishkahensis, 13; pl. 3 

Ophiodermella olympicensis, 9, 11; pl. 1 

oregonensis, Cancellaria, 3 

Cryptonatica, 9, 11; pl. 2 

Scutellaster, 12 

Otter Point Formation, 3 

p 

packi,Nucella,3,9, 11;pl.1 

pajaroanus, Tresus, 13 

Pandora sp., 13 

parilis,Felaniella, 13; pl. 3 

Patino pecten, 7, 11, 14 

caurinus, 14 

coosensis, 12 

Pecten Point, 12 

petricola, Littorina, 13 

Pillarian Stage, 9 

Polinices lincolnensis, 9; pl. 1 

victorianus, 11 

sp., 13 

Port Orford Formation, 3, 14 

Portlandia sp., 7 

praecursor, Spisula, 13 

praereinhaldii, Nitzschia, 14 

praerupta, Crepidula, 9, 11; pl. 2 

precursor, Thais, 3 

princeps, Crepidula, 11, 13 

INDEX 

Prisco{ usus medialis, 9, 11; pls. 1, 2 

Psephidia, 14, 16 

Pseudocardium sp., 12 

pseudocrux, Distephanus speculum, 14 

pseudofibula, Distephanus, 14 

R,S 

rostra/is, Crepidula, 9, 11; pl. 1 

Rouxia californica, 14 

SandstoneofFlorasLake, 1,3,4,6,8,9, 11,16 

Saxidomus giganteus, 11, 13 

schenckii, Stephanopyxis, 14 

scissurata, Cnesterium, 7, 13 

Scutella blancoensis, 2, 3, 14, 15 

(Kewia) blancoensis, 14 

Scutellaster oregonensis, 12 

secta, Macoma, 9, 13; pl. 2 

Securella, 4 

sec uris, 7, 11, 12, 13, 14; pl. 3 

sp.,.9; pl. 2 

securis, Securella, 7, 11, 12, 13, 14; pl. 3 

selbyensis, Spisula, 9. 11; pl. 2 

Siliqua Iucida, 13; pl. 3 

Solen conradi, 9, 11; pl. 1 

speculum pseudocrux, Distephanus, 14 

Spisula, 10, 11 

albaria, 6, 9, 11; pl. 1 

coosensis, 13 

praecursor, 13 

selbyensis, 9, 11; pl. 2 

sp., 11 

stanfordensis, Fusus (Bruclarkia), 3 

Stephanopyxis schenckii, 14 

stuarti, Trophonopsis, 13; pl. 3 

subdiaphana, Compsomyax, 7 

sulcatus, Liomesus, 13 

T 

Tellina, 15 

aragonia, 13 

bodegensis, 13 

emacerata, 9, 11; pls. l, 2 

Tellinella merriami, 13 

Temblor Stage, 9 

temperi, Coscinodiscus, 14 

Terebratalia transversa caurina, 13 

Thais precursor, 3 

Thalassiosira lineata, 14 

tintinnabulum coosensis, Balanus, 13 

transversa caurina, Terebratalia, 13 

Tresus pajaroanus, 13 

trilineata, Anadara, 13 

Trochita n. sp., 13 

Trophonopsis stuarti, 13; pl. 3 

sp., 13; pl. 3 

V,W,Y 

victorianus, Polinices, 11 

vulgaris monicae, Actinoptychus, 14 

Wishkahan Stage, 2, 9, 14, 15 

wishkahensis, Opalia, 13; pl. 3 

Y oidia carnerosensis, 11; pl. 1 

cooperi, 9, 13 

(Kalayoldia) carnerosensis, 9 

sp., 11 
PLATES l-3 

[Contact photographs of the plates in this report are available, at cost, from the U.S. Geological 

Survey Photographic Library, Federal Center, Denver, Colorado 80225] 
PLATE 1 

Macroi nvertebrate fossils from the sandstone of Floras Lake. All specimens natural size unless 

otherwise indicated. 

FIGURE 1. Nucella packi (Clark). USNM 245694. USGS loc. M4129. x2. 

2. Bruclarkia oregonensis (Conrad). UO F-29713. UO loc. F2011. 

3, 4. Nucella packi (Clark). USNM 245695. USGS loc. M3637. xH~. 

5. Nucella packi (Clark). USNM 245696. USGS Joe. M4131. x1~. 

6. Cancellaria n. sp.? aff. C. alaskensis Clark. USNM 245697. USGS loc. M4136. x3, a 

rubber cast. 

7. Brucklarkia oregonensis (Conrad). USNM 245698. USGS loc. M4135. 

8. Polin ices lincolnensis (Weaver). USNM 245699. USGS loc. M4126. 

9. Natica cf. N. clarki Etherington. USNM 245700. USGS loc. M4126. x2. 

10. Priscufusus cf. P. medialis (Conrad). USNM 245701. USGS loc. M4126. x1~. 

11. Molopophorus matthewi Etherington. USNM 245702. USGS loc. M2142. x1~. 

12. Bruclarkia oregonensis (Conrad). USNM 245703. USGS loc. M4690, a rubber cast. 

13. Nucella packi (Clark). USNM 245704. USGS loc. M4129. x2. 

14. Liracassis sp. USNM 245705. USGS loc. M4132. 

15. Molopophorus cf. M. anglonanus (Anderson). USNM 245706. USGS loc. M2142. x2. 

16. Bruclarkia oregonensis (Conrad). USNM 245707. USGS loc. M2142. x1~. a rubber 

cast. 

17, 18. Crepidula rostral is (Conrad). USNM 245708. USGS loc. M2142. x1 ~-

19. Megasurcula sp. USNM 245709. USGS loc. M4132. 

20. Molopophorus matthnci Etherington. USNM 245710. USGS loc. M4132. 

21. Molopophorus mattlwwi Etherington. USNM 245711. USGS loc. M4690, a rubber cast. 

22. Nucella n. sp. A. UO F-29714. UO loc. F2011. 

23. roldia cf. Y carnerosensis Clark. USNM 245712. USGS loc. M4126. 

24. Solen conradi Dall. USNM 245713. USGS loc. M4126. 

25. Ophiodennella cf. 0. olympicensis Addicott. USNM 245714. USGS loc. M4690. x2, a 

rubber cast. 

26. Spisula albaria (Conrad). USNM 245715. USGS loc. M4135. x3, a rubber cast. 

27. Tellina emacerata Conrad. USNM 245716. USGS loc. M4126. 

28. Spisula albaria (Conrad). USNM 245717. USGS loc. M2142. 

29. Ophiodermella cf. 0. olympicensis Addicott. USNM 245718. USGS loc. M4126. x2. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 774-G PLATE 1 

5 

2 3 

4 

I 

6 7 

9 10 

15 

12 13 14 

11 

17 18 19 

22 

20 21 

24 

27 

MACROINVERTEBRATE FOSSILS FROM THE SANDSTONE OF FLORAS LAKE 
PLATE 2 

Macroinvertebrate fossils from the sandstone of Floras Lake. All specimens natural size unless 

otherwise indicated. 

FIGURE 1. Mytilus middendm1fi Grewingk. USNM 64706. USGS loc. M4130, a rubber cast. 

2. Nucella n. sp. A. UO F - 29714. UO loc. F2011. 

3. Kath erinella angustijrons (Conrad). USNM.245719. USGS loc. M41332, an internal 

mold showing pallial sinus. 

4. Mytilus middendorffi Grewingk. USNM 245720. USGS loc. M4130, a rubber cast. 

5. Macurna cf. M. secta (Conrad). USNM 245721. USGS loc. M2142. 

6. Crepidula praerupta Conrad. USNM 245722. USGS loc. M4136. 

7. Katherinella angushfrons (Conrad). USNM 245723. USGS loc. M4132, a rubber cast. 

8. Cancellaria n. sp.? aff. C. alaskensis Clark. USNM 245724. USGS loc. M4136. x2, a 

rubber cast. 

9. Kewia cf. K. blancoensis etheringtuni (Weaver). USNM 245725. USGS loc. M4126. x1Y2. 

10, 16. Olivella cf. 0. ischnon Keen . USNM 245726. USGS loc. M4126. x4. 

11. Priscofusus cf. P. medialis (Conrad). USNM 245701. USGS loc. M4126. x1 Yz. 

12. Tellina emacerata Conrad. USNM 245726. USGS loc. M4126. 

13. Nassm"ius arnoldi (Anderson). USNM 245727. USGS loc. M4690. x4, a rubber cast. 

14, 15. Nucel/a, n. sp. B. UO F - 29715. UO loc. F2011. 

17. OryptonaU:ca uregunensis (Conrad). USNM 245727. USGS loc. M4126. x1K 

18. Macoma cf. M. flag leTi Etherington . USNM 245728. USGS loc. M2142. 

19. Mytilus middendmffi Grewingk. USNM 647060. USGS loc. M4130, a rubber cast. 

20. Secur·ella sp. USNM 245729. USGS loc. M4136, a rubber cast. 

21. Spisula cf. S. selbyensis Packard. USNM 245730. USGS loc . M4136. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 77~G PlATE 2 

2 

3 

6 

4 5 

19 20 21 

MACROINVERTEBRATE FOSSILS FROM THE SANDSTONE OF FLORAS lAKE 
PLATE 3 

Macroinvertebrate fossils from the restricted Empire Formation. All specimens natural size 

unless otherwise indicated. 

FIGURE 1. Clinocardium meekianum (Gabb). USNM 264129. USGS Joe. M2141. 

2. Siliqua cf. S. Lucida (Conrad). USNM 264114. USGS Joe. M4125. x1Y2. 

3. Crepidula adunca Sowerby. USNM 264116. USGS Joe. M3965. x1Y2 . 

4. Acila blancoensis Howe. USNM 264131. USGS Joe. M2140. 

5. Calliostoma cammani Dall. USNM 264132. USGS Joe. M7369. x3. 

6. Chlamys hodgei (Hertlein), right valve. USNM 252508. USGS Joe. M3965. 

7. Trophonopsis ef. T. stuarti (Smith). USNM 264133. USGS Joe. M7369. x2. 

8. Glycymeris grewingki Dall. USNM 264118. USGS Joe. M2139. 

9. Chlamys hodgei (Hertlein). USNM 264134. USGS Joe. M7395. 

10. Siliqua cf. S. Iucida (Conrad). USNM 264135. USGS Joe. M4225. 

11, 12. Nassarius andersoni (Weaver). USNM 264123. USGS Joe. M7369. x3. 

13. Nucella lima (Gmelin). USNM 264136. USGS Joe. M7369. x2 Y2 . 

14. Felaniella parilis (Conrad). USNM 264124. USGS Joe . .M7369. 

15. 'PI"ophonopsis sp. USNM 264137. USGS Joe. M7369. x2. 

16. Molopophorus bogachieli (Reagan). USNM 264126. USGS Joe. M4125. 

17. Kewia blancoensis (Kew). USNM 264127. USGS Joe. M4121. x1Y2. 

18. Chlamys sp. USNM 264138. USGS Joe. M7395. 

19. Opalia wishkahensis Durham. USNM 264120. USGS Joe. M4134. x1Y2 . 

20. Securella securis (Shumard). USNM 264128. USGS Joe. M4125. 

21. Securella securis (Shumard). USNM 264130. USGS Joe. M4124. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 774-G PLATE 3 

19 20 21 

MACROINVERTEBRATE FOSSU..S FROM THE EMPIRE FORMATION (RESTRICTED) 

Shorter Contributions 

to General Geology 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 774 

This volume was published 

as separate chapters A-G 
UNITED STATES DEPARTMENT OF THE INTERIOR 

JAMES G. WATT, Secretary 

GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

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

Washington, D.C. 20402 
CONTENTS 

[Letters designate the separately published chapters] 

(A) Reconnaissance geology of the northern Yukon-Koyukuk province, Alaska, by William W. Patton, Jr. 

(B) Hetch Hetchy Reservoir quadrangle, Yosemite National Park, California-analytic data, by 

Ronald W. Kistler 

(C) Mount Abbot quadrangle, central Sierra Nevada, California-analytic data, by John P. 

Lockwood 

(D) Shaver Lake quadrangle, central Sierra Nevada, California-analytic data, by Paul C. Bateman and John P. Lockwood 

(E) The Uyaijah ring structure, Kingdom of Saudi Arabia, by F. C. W. Dodge 

(F) Biostratigraphy and paleoecology of the upper Miocene (Messinian) and lower Pliocene(?) Cerro 

de Almendral section, Almeria Basin, southern Spain, by Richard Z. Poore and Sean 

Murphy Stone 

(G) Biostratigraphy of the marine Neogene sequence at Cape Blanco, southwestern Oregon, by 

Warren 0. Addicott 
GPO 687-040/104