Transactions and Proceedingsof thePalaeontological Society of Japan
New Series

No. 83

Palaeontological Society of Japan
September 20, 1971

Editor : Takashi HAMADA
Associate editor: Yasuhide IWASAKI

Officers for 1971 - 1972
President:

Tokio SHIKAMA

Councillors (* Executives) : Ki yoshi ASA NO*, Ki yotaka CHINZEI*, Takashi HAMADA*,
Tetsuro HANAI*, Kotora HAT AI, Itaru HAYAMI, Koichiro lCHIKA WA, Taro
KANAYA, Kametoshi KANMERA, Tamio KOTA KA, Tatsuro MATSUMOTO*, Hiroshi
OZAKI*, Tokio SHIKAMA *, Fuyuji T AKAI*, Yokichi TAKA YA NAGI
Secretaries : W ataru HASHIMOTO, Sabu ro KA NNO
Executive Committee
General Affairs:

Tetsuro HANAI, Naoaki AOKIMembership: Kiyotaka CHINZEI, Toshio KOIKE
Finance: Fuyuji T AKAI, Hisayoshi !GoPlanning:

Hiroshi OZAKI, Kazuo ASAMA

Publications
Transactions:
Special Papers:

Takashi HAMADA, Yasuhide IWASAKI
Tatsuro MATSUMOTO, Tomowo OZAWA" Fossils" : Kiyoshi ASANO, Toshiaki TAKAYAMA

All communications relating to this journal should be addressed to the
PALAEONTOLOGICAL SOCIETY OF JAPANcjo Geological Institute, Faculty of Science, University of Tokyo, Tokyo 113, Japan

Sole agent: University of Tokyo Press, Hongo, Tokyo

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 83, pp. 131-142, pl. 15, September 20, 1971

582.

FORAMINIFERA FROM THE HAYAMA GROUP,MIURA PENINSULA*KENJI KURIHARA

Institute of Geology and Mineralogy, Tokyo University of Education::::=:riff~~.

!X~il.JF.if.roYfoHL.'RH:.:t:i:tq'*Jil W~. ::::=:iil)$,1aj0) rp~;i!li::.iJE~T 0 :\\hiJJ\l'if,f.O)*-

15 :f:ilt.J/il,i.l, G, ~{9 90 f!l\O)tf:fL.'R it::fi~l*iiiU-- t..:o iiSLIJWIJlf.O)ff:fL.'R 7:1- i'i, :fo t vc, li:P1't
filli.I>..$.~-90/E;i't!Hlli.I,Gt.~: IJ, IJLfO)rp · Ttfll'+'i:1i'MC!c~\'fi'i&l'i'~t.~:til!~filts, bathyal waterO)fJl't:i:JE~~-J-, 3 --:>O)Jlif2FI'HL.'Rtlf.~i.l'il.2.10G:h.-0o i-¥~Vl:1HL.'Rf'i, iilill',i.I'PRGh0;?:, r
ff!lrp:j'ifr~:fEO)t~i'i&hTI-r:· Jr:, 0 Catapsydrax dissimilis -? Globigerinatella insueta >2'ittfll1':f:R:
f.I'~I>':>G:h.-00 111f£BJ::lfi-¥~VEf.ffL.'Ri.I,G, mill!W1lf.O):!Iflt>2~NL, ~b< c tfiiJF.>JJlh'i1:r§!\O)~Ffl\'h'J>rfirlrp:j;Ji*it-c· Jr:, 0 c. c ~7); L t..:o ~ t..:, UH~D.>.J~~R.: 5J;f[d- 0 f:!ll:SJI\"iTif.rjt fC,'f4~il.JF.fllfO)})iiQjiHL.'R ll!J\JfSfr.~Jl{J.:;I_ T 0'!1¥::\~f.lq'ftET 0 c. rc:.~:h.-0
t 1::., 1 ?ffrHt~Hcii\X L

c

t..:.

Introduction

cc

*

If){

\\lit

=

discuss their geologic age and there isno other paleontological report up tonow, nobody has referred the geologic
age of the group based on adequate
paleontological evidences.
The present author found foraminiferal fossils at a few exposures during
the course of the stratigraphical surveyof the Hayama area in 1968. Although theforaminifers are very limited in occurrence and poorly preserved in general,
he was just able to obtain fifteen samples
from the Hayama group containing afairly large number of the benthonicforaminifers. Among them, arenaceous
ones are rather dominant and are sometimes associated with planktonic species.
This foraminiferal fauna is believed tobe very valuable for the considerationof the geologic age, correlation andpaleoenvironment of the group. Therefore, the present paper treats of thefauna from the standpoint of above
mentioned respects.

The Hayama group is distributed in
the central part of the Miura Peninsula,
Kanagawa Prefecture, within the zonal
area extending from Y okosuka on theTokyo Bay side to Hayama on the Sagami Bay side of the peninsula (Text-fig.
1). The stratigraphic studies of thegroup have been reported by many
authors, and the detailed geological maps
were published recently by MITSUNASHI
and Y AZAKI (1968) and WATANABE et al.
(1968).
It is well known that the Hayama
group is hardly yielding any fossil except for echinoid spines and Makiyamasp. (WATANABE, 1954). Subsequently,
Boso and Miura Research Group (1958)
reported the occurrence of some planktonic foraminifers from the Hayama
group. As these are too inadequate to* Received August 10, 1970; read June 14,
1969.
131

,....
~

t-:l

•
@

Ultrabasic Rock
Igneous Rockz [SSj Mudstoneus §3 ConglomerateHm Yab• F.

A~~ Limestone

A
M

H

I

y

A
G.

Kinugasa

Oyama
km

CJ. 0 saw a~

Toneyama~ Morita~""....

<S

.,.,:
~

c:::

::>;)

......

~
::>;)
;A

t

Text-fig. 1. Sample locality and geological map of the central part of the Miura Peninsula, mostly after WATANABE et al. (1968).

582.

Foraminifera from the Hayama group

Stratigraphy and sample locality
The Hayama group is the oldest series
in the Miura Peninsula. It is measured
more than 3,000 m in thickness and con·sists mainly of tuffaceous sediments,
such as tuff, tuffaceous mudstone, tuffa·ceous sandstone and tuffaceous conglomerate. It shows a general strike of
NW -SE, dipping to northeast at angles
from 50° to vertical. The Hayama grouphas rather complicated structure with a·COnsiderable number of faults runningon the directions of E-W and NE-SW.
The present group is divided into six
formations as shown below in descending order. These formations are conformable with each other.
Yabe Alternation: 600 m+. Alternation of
tuffaceous sandstone and tuffaceous siltstone.
Kinugasa Mudstone: 800 m+. Massive tuffaceous mudstone, sometimes intercalating thin tuffaceous sandstone beds.
·Oyama Sandstone: 700 m+. Cross-laminatedtuffaceous fine- to medium-grained sandstone.
·Osawa Conglomerate: 300-400 m. Massive
granule or pebble conglomerate; composed chiefly of well-rounded granules ofchert and pyroclastics.
Toneyama Alternation: 400-500 m. Alternation of tuffaceous fine- to coarse-grainedsandstone and tuffaceous siltstone.
Morita Mudstone:
700 m +.
White finegrained tuff, sometimes intercalating
tuffaceous coarse-grained sandstone andsiltstone, with massive siltstone at theupper.

The radiolarians occur fairly common
from the tuff and mudstone of the Hayama group associated with diatoms,
foraminifers, Aiakiyama and fragments·Of molluscs, though the last ones arevery few. The foraminifers are foundfrom dark-grey or black colored siltstonewhich is less tuffaceous than other rocks.

133

Among fifteen fossiliferous samples
thirteen are collected from the Morito
formation of the lowest part of the
Hayama group and the rest from the
Toneyama and Kinugasa formations respectively.
The locality, lithology and stratigraphic position of these samples are
given in the following lines.
Morita formation (Samples are ar-ranged approximately from south to north. Asterisk indicates the upper part of theMorita formation.);!7296: Roadside exposure at Koyasu, northof Hikageyama, Yokosuka City;
black siltstone.
;7299: Small seaside exposure near themouth of a stream, Akiya, Yokosuka City; dark-grey siltstone intercalated with( fine- to mediumgrained sandstone.
:!;:7435: Small western ·'Cliff in the uppercourse of the same stream; darkgrey siltstone intercalating thinfine- to medium-grained sandstone.
:;:7439: Western cliff in the upper courseof the same stream; massive darkgrey siltstone.
:::7287: Stream floor south of Okuzure, Yokosuka City; greenish-grey siltstoneintercalated with medium-grainedsandstone.
;;7454: Exposure at the beach of Manase,Hayama Town; dark-grey sandy
siltstone intercalated with conglomerate.
:;;7092 and 7091 : Exposures at the beach of
Morita, north of Morita Shrine,
Hayama Town; dark-grey siltstoneintercalated with medium-grainedsandstone.
;;7463: Exposure at the beach of Morita,
north of Morita Shrine, Hayama
Town; massive dark-grey siltstone.
;;7086* and 7088* : Exposure along the pathfrom Hiramatsu to Sengenyama,
Hayama Town; massive dark-greysiltstone.
:!f7096*: Roadside cliff at a small valley

134
northwest of Takinosaka, Hayama
Town; massive dark-grey siltstone.
#7116: Exposure along a stream at Teramae, Hayama Town; dark-greysiltstone intercalated with mediumgrained tuffaceous sandstone.
Toneyama formation;t7117: Roadside cliff at Kamiyamaguchi,
Hayama Town; massive dark-greysiltstone, in the lower part of the
Toneyama formation.
Kinugasa formation#7452: Cliff about 400 m south of Kinugasa
railway station, Yokosuka City;
dark-grey tuff.aceous mudstone intercalating thin medium-grainedsandstone, in the upper part of the
Kinugasa formation.

Fauna

About 90 species of benthonic andplanktonic foraminifers are found in the
15 samples from the lower and upperparts of the Hayama group. The fauna
is composed mainly of benthonic species,
but planktonic forms are very few.
BENTHONIC FORAMINIFERAFrom the association of the dominantand characteristic species three benthonic foraminiferal assemblages are
distinguishable, that is, (1) Assemblage
A consisting of rich arenaceous foraminifer, (2) Assemblage B consisting
chiefly of calcareous benthonic species,and (3) Assemblage C comprising meagre
arenaceous foraminifer.
Assemblage A is represented by fivesamples which are restricted to the lower
or middle part of the Morito formation.
Assemblage B is represented by a single
sample (#7454) collected at the beach of
Manase, Hayama Town, probably fromthe middle part of the Morito formation.
Assemblage C may be more prevailed
in the Hayama group. It occurs fromthe middle and upper parts of the Morito,
the lower part of the Toneyama, andthe upper part of the Kinugasa formations. In other words, three types of theassemblages are found within the Morito,
and the arenaceous foraminiferal one(Assemblage C) extends in occurrence
up to the Kinugasa of the upper part of
the group.
The faunal characteristics of thesethree assemblages are briefly remarked
as below.
Assemblage A: This assemblage consists of rather large number of species
and individuals, and is characterized by
the abundance of the arenaceous benthonic foraminifers including calcareous
benthonic as well as planktonic species
in low frequencies. This assemblage ispredominated by Martinottiella communis(D'ORBIGNY) and Cribrostomoides l<yushuense ASANO. The two species constitute
usually more than 15 per cent of thetotal benthonic faunas respectively. The
associated species are : Ammodiscus cf.
intermedius HOEGLUND, Cyclammina orbicularis BRADY, C. j;usilla BRADY, Dorothia sp. A, Reophax sp., Nodosaria longiscata D'ORBIGNY and " Globobulimina " sp.
Nodosaria sp., Astrononion sp. and Melonis pompilioides (FICHTEL and MOLL) arefound very rare in one sample (#7299).
Assemblage B : The assemblage isquite different from others in having arich fauna consisting mostly of the calcareous foraminifers. Although it isrepresented by only one sample (#7454),
it contains about sixty species of thecalcareous benthonic and ten species ofarenaceous foraminifers. As most ofthese species are absent in the othertwo assemblages of the Hayama group,
they are listed below. The predominant
species in this assemblage are Martinottiella communis and Nodosaria longiscata, and both species constitute about.

582.

Foraminifera from the Hayama gro1~p

20 per cent of the total benthonic fauna
respectively. The other common species
are: "Globobulimina" sp., Hoeglundina
elegans D'ORBIGNY, Bulimina striata
n'ORBIGNY, Spirosigmoilinella compressa
MATSUNAGA, Melonis pacificus (CUSHMAN)
and Pullenia bulloides (D'ORBIGNY). The
arenaceous species of Cyclammina andCribrostomoides which are characteristic
to the other assemblages are rare inthis assemblage.
Proteonina sp.
+
Psammosphaera sp.
1
Ammodiscus cf. intermedius HoEGLUND+
Reophax sp.
1
Spirosigmoilinella compressa MATSUNAGA 5
Haplaphragmoides cf. scitulum (BRADY)
1
Cyclammina japonica AsANO+.C. pusilla BRADY
1
Trochammina nobensis AsANO+
Martinottiella communis (D'0RBIG1'Y)
20
Quinqueloculina seminula (LI"'NAECs)+
Q. vulgaris D'0RBIGNY
1
Pyrgo murrhina (Sci-IW AGER)
1
P. cf. fornasinii CusHMAN and PARR+
Sigmoilopsis schlumbergeri (SILVESTRI)
1
Nodosaria longiscata D'0RBIGNY
19
N. acuminata uniforminata LEROY+
N. tosta ScHWAGER+
N. sp.
1
Dentalina spinosa D'0RBIGNY+
Lagena apiopleura LoEBLICH and TAPPAN +Lenticulina sp.
+
Plectofrondicularia cf. niinoi UcHIO+
Fissurina sp.
+
Parajissurina ovalis ToDD+
Tosaia hanzawai TAKAYANAGI
1
Sp/weroidina bulloides D'0RBIGNY+
Brizalina cf. albatrossi ·(CusHMAN)+
Stilostomella consoblina (D'0RBIGNY)
3
S. ketienziensis (IsiiiZAKI)+
5. lepidula (Sci-IW AGER)+
S. spp.
+Bulimina rostrata BRADY
1
B. striata D'0RBIGNY
5"' Globobulimina" sp.
7
Uvigerina bosoensis AoKr
3
U. crassicostata ScHWAGER+
Trijarina cf. kokozuraensis (AsANO)
1

135
+

Discorbis sp.
Eilohedra rotunda(HusEZIMA and MARUI!ASI)+

Laticarinina pauperata+(PARKER and ]ONES)

Cibicides cf. aknerianus (D'0RBIG1'Y)
C. pseudoungerianus (CusHMAN)
Pleurostomella alternans Scr-Iw AGER
P. brevis Sci-IW AGER
Cassidulina depressa

Astrononion cf. hanyudaense MATSUNAGA
A. hayamaense n. sp.
Pullenia apertula CusHMAN
P. bulloides (D'0RBIGl':Y)Gyroidina cf. orbicularis D'0RBIG?\"Y
G. profunda AoKI
G. altijormis R.E. and K.C. STEWART
Oridorsalis umbonatus (REuss)
Osangularia bengalensis (Sci-IW AGER)
Cibicidoides bradyi (TRAUTH)
Hanzawaia nipponica ASA!\Oi\lelonis pacijicus (Cusi-J:'viAN)
M. pompilioides (FrcrrTEL and MoLL)
Hoeglundina e!egans (D'0RBIGNY)
abundance

is

given

+
+

+

AsANO and NAKAMURA

C. kattoi TAKAYANAGI
C. subglobosa BRADY(Species

1

2

+
+
+
+
+
4

+
+
+
2

+
2

+
4

+
6

in per cent.

Cross shows less than 1 per cent.)

Assemblage C: The numbers of benthonic species and individuals are limited
and usually ten or less numbers of specimens are obtained from each sample
belonging to this assemblage. In total,
it is composed of nine species of thearenaceous and two species of calcareous
benthonic foraminifers. The latter forms
are found in two samples, associatedwith the former ones. The most common
species is i\!Iartinottiella communis. The
three species of Cyclammina, that is,
Cyclammina japonica ASANO, C. orbicularis and C. pusilla, occur in this assemblage. The following species are
rarely found: Haplaphragmoides cf. scitulum (BRADY), Ammodiscus cf. intermedius, Dorothia sp. A, R habdamminasp., Nodosaria longiscata and " Clabo-

136

Kenji KURIHARA

bulimina" sp.

BERMUDEZ) is n,1ther frequent and about
twenty specimens of this species are
obtained from one planktonic foraminiferous sample of the lower or middle
part of the Morito formation collectedat Akiya, Y okosuka City (#7299). In
addition to this species the following
two species are recognized from thesame locality, but about a half of planktonic specimens cannot be identified specifically, because of their poor preser:
vation and deformation.

PLANKTONIC FORAMINIFERA
Among the fifteen samples the planktonic foraminifers are restricted withinfour samples from the Morito and Toneyama formations. Moreover, two ofthese planktonic foraminiferous samples
yield only a small number of specimens
which are so poorly preserved that theycannot be determined specifically.
Catapsydrax dissimilis (CUSHMAN and
Table l.

Distribution of benthonic Foraminifera in the
Hayama group (in per cent).
-----------------------------~---

Assemblage

c

B

A

Sample Number
Species
Rhabdammina sp.
Ammodiscus cf. intermedius HoEGLUI"D
6
Reophax sp.
5Spirosigmoi!inel!a compressa MATSU?\AGA
Cribrostomoides kyushuense AsAi'\0~ 20 18
I

Haplaphragmoides cf. scitu!um (BRADY)
Cyclammina japonica AsANO
C. orbicularis BRADY
C. pusi/!a BRADY
C. spp.
Dorothia sp. A
sp. B
D.
M artinottiel!a communis (D'0R BIG:\Y)
Nodosaria !ongiscata D'0R BIG:\Y
Bulimina striata D'0I< BIG NY

I

+ +

1 8
3
9 24 15
2

1

+

9
5

+

3

+
+

+

+

+

+

+

3

2

5 2
'30 40 36 17 73 20 +10
1 1 19,5.
-- I

Plank.jBentho. +Plank.

2+2" Globobulimina" sp.
Pul!enia bulloides (D'OR BIGI"Y)
Melonis pacificus (CusHMAN)
M. pompi!ioides (FICIITEL and MoLL)
Hoeg!undina elegans (D'0RBIGi'\Y)

spp. (Arenaceous)
spp. (Calcareous)++2
3 11 15

2

+

+ +
1 + 1

I

+
+
+

5

1 2

20

+

+

+

+

81
4

+

I

I

4 +

7 71
4,

4!
3

+,
6,

124

_I

3 23 26
1

2. 2. +
2 u

+

+

+

+

5 +

+

o 7 o o 2. 4oJ o o o o o. o o 6 o582.

Foraminifera from the Hayama group

Catapsydrax dissimilis(CUSHMAN and BERMUDEZ)
Globigerina glutinata EGGER
G. cf. praebulloides BLO\\"frequentrare
rare

A rich planktonic fauna is found at
the seaside exposure of Manase, Hayama
Town, from the middle part of the Morito formation (1f7454). In this sample
the number of the planktonic specimens
is fairly large and amounts up to 40
per cent of the total fauna. Fifteen
species are identified as:
Globorotalia birnagea BLow
commonG. fohsi peripheroronda
BANNER and BLOW
commonG. cf. scitula praescitula BLo\\·rare
G. zealandica HoRNillROOK
rare
Globigerina glutinata EGGER
commonG. angustiumbil£cata BoLLI
rare
G. falconensis BLo\\·rare
G. praebulloides BLowrare
Globoquadrina altispira(CUSHMAN and ]ARVIS)
rare
G. dehiscens (CusHMAN,
PARR and CoLLI:'\s)commonGlobigerinoides transitorius BLowrare
G. ruber subquadratus BRONNIMANN rare
G. sacculifer (BRADY)
rare
G!obigerinatella insueta
CUSHMAN and STAI:'\FORTI-I
rare
Sp!weroidinella seminu!ina(SCHWAGER)
common(rare <20 specimens, common >20 specimens)

Among them Sphaeroidinella seminulina
and Globoquadrina dehiscen s are mostcommon and Globorotalia bimagea andGlobigerina glutinata are also characteristic in this sample. Other species occur
in lower frequencies than the former.
Globigerinatella insueta is determinedbased on only two specimens.

Ecologic notes
The benthonic foraminiferal fauna of
the Hayama group is dominated by the137

species belonging to the genera Martinottiella, Cribrostomoides, Cyclammina
and Nodosaria. Among these genera
Cyclammina is most characteristic indeep water environment. It is also
noteworthy that the genera Ammonia,
Elphidium, Florilus and Hanzawaia which
generally indicate shallow water environment are very rare in the group.
Some species of the benthonic forami·
nifers of the Hayama group are reported
from the Recent sediments. Ji.Jartinottiella communis predominates through thethree assemblages of the group, andcommonly occurs in the bathyal zone
off the Pacific coast of Japan (ISHIW ADA,
1964). Cyclammina orbicularis is consistently found in Assemblages A and C,
and was reported from the bathyal andabyssal water of modern seas (BRADY,
1884; and other). Many calcareous benthonic species occur in Assemblage B.
Most of these species show wide depth
ranging from outer neritic to bathyalzones. Moreover, this assemblage contains some bathyal water species, suchas Pyrgo murrhina, Bulimina striata and
Laticalinina pauperata. The presence ofshallow water species associated withthese deeper water assemblages may beinterpreted by the transport from theneritic zone.
Consequently, it can be said that thebenthonic foraminiferal assemblages ofthe Hayama group consist of bathyalwater species and indicate such water
depth.
In addition the bathyal water environment seems to be also suggested by theplanktonic foraminifers of the Hayama
group. The planktonic foraminiferal
assemblage found in the Morito formation is dominated by Sp!weroidinella
seminulina which is having a thick wallwith an outer cortex. BE (1965) statedthat a Recent planktonic foraminifer,

138

Kenji KuRIHARA

Sphaeroidinella dehiscens, secretes theouter cortex in order to adapt the highpressure of its deep water habitat usually in water depth from 300 to 2000 m
in modern waters. Therefore, BANDY,
INGLE and FRERICHS (1967) said that theoccurrence of Sphaeroidinella seminulina
is useful as one criterion interpretingas bathyal water depth.
Among the three benthonic foraminiferal assemblages of the Hayama group,
arenaceous benthonic foraminifers extremely predominate in Assemblages A
and C in which calcareous benthonicand planktonic forms are absent or rare.
These arenaceous assemblages may besuggesting the presence of stagnant
condition, which seems to be rather prevailing in time of the Hayama group,
because of their common occurrence inthis group. Similar arenaceous assemblages have been also reported from the
Miocene deposits of Japan, and especially from those of the oilfields of JapanSea coast region where the sedimentarybasins are considered to be largely instagnant condition judging from thesedimentological and paleontologicalstudies (IWAMOTO and SHINBO, 1964; andothers).

Correlation of the Hayama group

The Hayama group is overlain with
distinct clino-unconformity by the Zushi
formation which is generally regarded
as Upper Miocene in age. Based on thestratigraphic sequence, lithological andstructural characters, the Hayama grouphas been correlated with the Lower
Miocene deposits of the Tanzawa groupin Kanagawa Prefecture and the Yugashima group in the Izu Peninsula whichyield larger foraminiferal assemblage
consisting of Lepidocyclina and Miogypsina by KOJIMA (1954), WATANABE (1954)

and others.
In the preliminary study of the planktonic foraminifers of the Miura andBoso Peninsulas the occurrence of Globigerina cf. bulloides and Globorotalia hayamaense (MS) which is regarded as theprirr.itive form of Globorotalia fohsi (s.l.)group was reported from the Hayama
group, and it was noted that at least apart of the Hayama group is considered
to be Lower Miocene in age from theplanktonic foraminiferal assemblages(Boso and Miura Research Group, 1958).
In the correlation and age-determination of the Hayama group, the planktonic foraminifers are very useful inspite of their restricted occurrence inthe group. About sixteen species arefound in the samples of the Morito formation as mentioned above. Amongthem, eight species appear first in the
Miocene according to BOLLI (1957), BLOW
(1959) and others. They are, Globorotalia
birnagea, G. fohsi peripheroronda, Globigerina falconensis, G. glutinata, Globoquadrina altispira, Globigerinoides ruber
subquadratus, Sphaeroidinella seminulina
and Globigerinatella insueta. Although
the ranges of some species are extended
upwards to the Pliocene and even to the
Recent, Globigerinatella insueta, Catapsydrax dissimilis, Globorotalia birnagea andG. fohsi peripheroronda have shortly restricted ranges within the Miocene.
Globigerinatella insueta occurs rarelyin the middle part of the Morito formation (#7454) and it was reported to range
from the base of the Catapsydrax stainforthi to the top of the next younger
Globigerinatella insueta zones in Trinidad
and Venezuela (BOLLI, 1957; BLOW, 1959).
Catapsydrax dissimilis which is found in
the lower or middle part of the Morito
formation (#7299) was reported as
ranging from the Truncorotaloides rohri(Eocene) to the top of the Catapsydrax

582.

Foraminifera from the Hayama groupstainforthi zones (BOLLI, 1957; BANNER
and BLOW, 1962). Therefore, it may bereasonable that the horizon of the Mo·
rito formation is included within theinterval from the Catapsydrax stainforthi
zone to the Globigerinatella insueta zone
in Trinidad and Venezuela. The rangesof the other associated species do notcontradict this age-determination.
The Miocene planktonic foraminifers<>f various areas of Japan were studied
in detail by SAITO (1963). He recognized
the occurrence of Catapsydrax dissimilisin the Towata and Matsuba formationsand Globigerinatella insueta in the Matsuba and Saigo formations all of theMikasa group in the Kakegawa district.
The latter species was also reported
from the Chichibumachi group in Saitama Prefecture and the Fukushima formation in Gunma Prefecture both in the
Kanto region. It is noteworthy thatboth species are found together inthe Matsuba formation of the middle
part of the Mikasa group. Their stratigraphic ranges are not determined in
the Miura region, however, the common
occurrence of these two species indicatesthat a part of the Morito formation iscorrelated with a part of the Mikasa
group, probably with the Matsuba formation of the middle part of the group.
The planktonic foraminiferal assemblages of the Matsuba formation as well
.as the Mikasa group are assigned to the
Aquitanian of the Lower Miocene, thatis, to the Globigerinita unicava zone,.Gfobigerinate lla insueta I Globigerinoides
trilobus subzone and GlobigerinatellainsuetajGlobigerinoides bisphericus sub.zone by SAITO (1963). It may be addedthat the benthonic foraminiferal assemblages of the Hayama group are very
similar to those of the Mikasa groupreported by SAWAI (1962).
The Hayama group comprises some139

benthonic species characteristic to the
Miocene deposits of Japan. The speciesof Cyclammina are common in the lower
and middle of the Miocene deposits ofJapan. For instance, Cyclammina orbicularis was reported from the Masuporo
formation in Hokkaido and the Mikasa
group in Kakegawa. Cyclammina japonica frequently occurs in the Miocene
deposits of the oilfield of Japan Sea
coast region, and Cyclammina pusilla isalso found in the Miocene deposits ofJapan (ASANO, 1951; SAW AI, 1962; andothers). Spirosigmoilinella compressa wasreported to range from the Nanatani to
Teradomari formations which are regarded as Middle or Upper Miocene in
age in the oilfield of japan Sea coast
region (MATSUNAGA, 1963). Cribrostomoides llyushuense is originally describedfrom the Tsuma formation of the Miyazaki group in Kyushu and occurs in the
Operculina and Miogypsina-bearing formations of western Japan (T AI, 1959).
It is also pointed out that the benthonicfauna of the Hayama group contains
numerous species which are found in the
Miocene and Pliocene deposits of theMiura and Boso Peninsulas. The benthonic foraminifers of the Hayama groupare, therefore, characterized by the socalled Miocene species which are frequent especially in the Lower and Middle
Miocene deposits of Japan.
In the correlation of the Hayama
group, it is generally accepted that thegroup is the correlative of the Hota
group in the Boso Peninsula, on the
opposite side of Tokyo Bay, becauseof close similarities of the lithologicaland structural characters. Though theforaminifers have not been reported
previously from the Hota group, thepresent author could collect the foraminiferous samples at Godo and Heguri,
east of Iwai in the western part of the

140

Kenji KURIHARA

Boso Peninsula. The following sevenarenaceous species are found.
Ammodiscus cf. intermedius
Reophax sp.
Cribrostomoides kyushuense
Cyclammina japonica
C. orbicularis
Martinottiella communis
Rhabdammina sp.

It is interesting to note that all these
species are commonly found also in the
Hayama group. Furthermore, it can besaid that the faunal characteristic issimilar to Assemblage C of the group
described above.
Description of new species
Astrono;zion hayamaense

KURIHARA, n. sp.

having more inflated test and roundedequatorial periphery.

Acknowledgements
The present author wishes to thankProfessor Kagetaka WATANABE and Dr.
Toshio KOIKE, Institute of Geology andMineralogy, Tokyo University of Education, who suggested to initiate thepresent study, for their continuous encouragement. Deep appreciation is expressed to Dr. Naoaki AOKI, Tokyo
University of Education, for his valuableadvice and discussion during the courseof the present study. Thanks are also
due to Professor Wataru HASHIMOTO
and Dr. Saburo KANNO, Tokyo Universityof Education, for reading the manuscriptand hearty encouragement.

Pl. 15, Figs. 8a, b

Test small, inflated, equatorial periphery rounded, not lobulated, axial periphery broadly rounded, umbilical regionslightly depressed, umbilicus insignificant, chambers 7, rarely 6, in the lastwhorl, supplementary chambers not distinct, elongate tube with terminal rounded pore, sutures slightly curved backwards, wall smooth, finely perforate, aperture arched narrow slit at the base ofapertural face. Length of holotype, 0.29mm, width, 0.24 mm, thickness 0.20 mm.
Holotype, Tokyo University of Education Paleontological Collection Reg. no.
68051, from sample ±17454, seaside exposure at Manase, Hayama Town, Morito
formation of the Hayama group, Lower
Miocene, rare.
This form is characterized by small
and inflated test. The species is similar
to Astrononion pusillum HORNIBROOK described from the Upper Oligocene of
New Zealand, but differs from it byReferences
AsANO, K. (1951): Illustrated Catalogue ofJapanese Tertiary Smaller Foraminifera,
pt. 9-13, pp. 1-19.
BANDY, O.L., Ii\GLE, ].C. and FRERICHS,
W.E. (1967): Isomorphism in "Sphaeroidinella" and " Sphaeroidinel!opsis ".
Micropal., vol. 13, no. 4, pp. 483-488, pl. l.
BE, A. W.B. (1.965) : The influence of depth
on shell growth in Globigerinoides sacculifer (BRADY). Ibid., vol. 11, no. 1., pp.
81-97, pis. 1-2.
BLO\Y, W.H. (1959): Age, correlation, andbiostratigraphy of the Upper Tocuyo(San Lorenzo) and Poz6n formations,eastern Falcon, Venezuela. Bull. Amer.
Pa!eont., vol. 39, no. 1.78, pp. 67-251, pis.
6-19.
- - and BANNER, F.T. (ll'l62): The midTertiary (Upper Eocene to Aquitanian)Globigerinacea. in Fundamentals of midTertiary stratigraphical correlation. pt.
2, pp. 61-1.51, pls. 8-17, Cambridge Univ.
Press.

582.

BOLLI, H.M. (1957) : Planktonic foraminiferafrom the Oligocene-Miocene Cipero and
Lengua formations of Trinidad. U.S.
Nat!. Mus., Bull. 215, pp. 125-131, pl. 30.
Boso and Miura Research Group (1958) :Cenozoic planktonic foraminiferal zonation. Foraminifera, no. 9, pp. 34-39 (inJapanese).
IsHII\' ADA, Y. (1964): Benthonic foraminifera off the Pacific coast of Japan, referred to biostratigraphy of Kazusa
group. Rept. Ceo!. Surv. japan, no. 205,
pp. 1-45, pis. 1-8.
lwAL\:IOTO, H. and SIII:-;Bo, K. (1964): Considerations on paleogeography of the
Niigata oil field, based upon foraminifera.
Fossils, no. 8, pp. 1-11 (in Japanese).
KoJIMA, N. (195,1): On the Hayama groupof the Miura Peninsula, Kanagawa Prefecture, South Kanto, Japan. jour. Ceo!.
Soc. japan, vol. 60, no. 700, pp. 1-6 (inJapanese).
MATSUNAGA, T. (1963) : Benthonic smaller
foraminifera from the oil fields of northern Japan. Tohoku Univ. Sci. Repts., ser.
2, voi. 35, no. 2, pp. 67-122, pis. 24-52.
MITSUNASHI, T. and Y AZAKI, K. (1968):

Akiya
Boso
Chichibumachi
Fukushima
Go do
Hay am a
Heguri
Hikagey am a
Hiramatsu
Hot a
Iwai
Izu
Kakegawa
Kamiyamaguchi

{;k
JJ}

:f1-I
a~

tkSi:lllJ

thl

~l£j

/>..

p

"

.,•,•,:

141

Foraminifera from the Hayama group:A...:

Lli

ljf.

/if

Jl)i;;,Jj

sv.

~,,~~

i;f:

Ill

~5

-;J:i•.

ift

.u..

,-_,

m JIJ

l:JLJr::lKinugasa
KoyasuManaseMasuporo
MatsubaMikasaMiura
MiyazakiMoritaNanatani
OkuzureOsawa
Oyama
Sagami

Geological maps of the oil and gas fieldof Japan 6, "Miura Peninsula", Ceo/.
Surv. japan.
SAITO, T. (1963): Miocene planktonic foraminifera from Honshu, Japan. Tohoku
Univ. Sci. Repts., ser. 2, vol. 35, no. 2,
pp. 123-209, pis. 53-56.
SAw AI, K. (1962): Orbulina universa o'ORll!G:-;Y in central Japan. Mem. Coli. Sci.
Univ. Kyoto, ser. B, vol. 29, no. 2, pp.
113-159, pis. 1-4.
TAI, Y. (1959):
Miocene microbiostratigraphy of west Honshu, Japan. jour.
Sci. Hiroshima Univ., ser. C, vol. 2, no.
4, pp. 265-395, pis, 39-43.
vVATA1\ABE, K. (1954): Tertiary structureof the western Kwanto district, Japan
with special reference to the crustal
movement in the Yorii Phase. Sci. Rept.
Tokyo Kyoiku Daigaku, sec. C, vol. 3, no.
z,l, pp. 199-280.
- - , KOIKE, T. and KURIHARA, K. (1968):
Geology of the Hayama area, Kanagawa
Prefecture. japan Soc. Earth Sci. Education, Tokyo, pp. 1-33, pis. 1-4 (in Japanese).

1.<
.:Y-

;,.~,.

:l.!.:.

'};;

It!iJitJ!
lt;(j

~Ihl

t-1.~

If

·--·

'11:.

'I ~ t'

''

ifll
w~r

;f'~

p

·t

~-')-

J:. i111
):.
-):_

in
ill

Hl

-~~

Saigo
Sengenyama
Takinosaka
Tanzawa
Teradomari
Teramae
Toneyama
TowataTsuma
Yabe
Yokosuka
Yugashima
Zushi

i1I'i ~ur,f:JJ:li:LlJ

i·ii J :!ti

n

iR

is

~
-=1-~

j)lj

··J•

PtHJIJ<'trllFi n:111
jj_(:

!X:.

,'!..'!
11P

fii'{JriY:i¥~/}7 ~~J

;g -=t-142

Kenji KURIHARA

Explanation of Plate 15
Fig. l. Cyc!ammina orbicularis BRADY, x 24, from sample #7439.
Fig. 2. Spirosigmoilinella compressa MATSUNAGA, x 60, from sample #7454.
Fig. 3. Martinottiel.!a communis (D'0RBIGNY), x 35, from sample #7439.
Fig. 4. Nodosaria longiscata D'0RBIGNY, x 35, from sample #7454.
Fig. ;:,, Bulimina striata D'0RBIGNY, x 60, from sample #7454.
Fig. 6. Pul!enia bulloides (D'0RBIGNY), x 70, from sample :ii7454.
Fig. 7. Melon is pacijicus (Cusii:\IAN), x 60, from sample :;;7454.
Fig. 8. Astrononion hayamaense KuRIHARA, n. sp., x 80, from sample #7454.
Fig. 9. Hoeglundina elegans (D'0RBIGr\Y), x25, from sample ;!7454.
Fig. 10. Sphaeroidinella seminulina (SCHWAGER), x 50, from sample #7454.
Fig. 11. Globoquadrina dehiscens (CusHMAN, PARR and CoLLINs), x90, from sample #74S4.
Fig. 12. Catapsydrax dissimilis (CusHMAN and BERMUDEZ), x 67, from sample #7299.
Fig. 13. Globigerinatella insueta CusHMAN and STAINFORTH, x 110, from sample #7454.

KURIHARA :Foraminifera from the Hayama group

Plate 15

fJ m
f!
t'

·~

I

lb

!a

2

3
4

6a

5

Sa

Sb

12c

7b

9c

9b

12a

13a

7a

9a

llc

llb

lOb

lOa

12b

6b

lla

13b

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 83, pp. 143-161, pis. 16-18, September 20, 1971

583.

NANNOFOSSILS FROM JAPAN IV.

CALCAREOUS NANNOPLANKTON FOSSILS FROM THE
TONOHAMA GROUP, SHIKOKU, SOUTHWEST JAPANSHIRO NISHIDA
Department of Earth Science, Nara University of Education, Nara, Japan

13 :2j\;:ii:M:H~fi::;:P N. Jm!E • l!f J ~I\>;IMOJEEk'f1::T; 7"7 '/ ~ 1- '/{1::;15: 4-~ "CR~ftil6liil"~t.:J\l1Ff,:O)J:il' GF~~Jm2: ~:!1,""( ~t.: J;!f ~~~~lifO)~~ 2: /Ci*J~IC"?It'""C:.fiEJ('["t :T / 7"7'/ ~ 1- '/fl::;ilil' G .7;!.t.:J!ij¥;a-Jitt....::.t.:o ~ t.:jiljf~;;, Gl!fi:H:\ L.t.: U!TEI!:a-~tr 31 fi.JlOJilEk'N:t- J
7"7 '/ ~ 1- '/:a-~cn& L.t.:o :T / 7"7 :/ ~ 1- '/jlH((:tJ>G.7;!. ""C ~~~~H:l: HAY & ScHMIDT (1967)
G,0) Discoaster surculus ;~~. MARTINI & WoRSLEY (1970) 0) NN16 ;w,:"?~ t) Discoastersurculus 1il'IC:itt.l:l:~tL. 1CI*l/l'11:l:M":ffOJ Discoaster e:ctensus ;lll'~t.:i:l: Discoaster brouweri'li~. i':lt:ffOJ NN18 ;llffJ:It' L. NN17 1f,="?~ ~ Discoaster brouweri 1J\=tJ:It' L. Discoasterpentaradiatus ff,IC:)(t .1:1: ~ ;h.:Q o L.il> L.~~il'; l:l: Discoaster dilatus, Dis coaster kugleri,
Dis coaster stellulus, Discoaster tani ~ Ceratolithus aff. C. tricorniculatus 0) .t ? tJ: l=j:1

Wfr"l!!:H'iYlf,t-?I:T:Qf!ll"i>il'tJ: fJ .7;!.Gh • .:COJi:~F{¥~;1;~tJ:cii'G =<xli::;:fi"t'·:b:Q 2: {, ~X.Ght.:"' 1:. 2: il' ;, .:COJII~ftl:l:'0'2: ~f :liil:-HBtJ:v' L. -nB!!.'i'W!TiJt 2: L.. /Ci*ll\"iiC "?v'""C IX"fl'\GfJ:v'
L.l=j:IRflf!¥*JTil!: 2: L. ""C .td' <o 1:. OJ 1:. 2: IHffL!B. ~ & fl~:.fiil' G .7;!.t.: *5:\ll: 2: {, .t <1\ffllfni"" :Q o :T J
7'7 '/~ 1- '/llf~~:J:~m. xl*l~c "i> -T 1 A::! -:A !il-:a-Jl.,j<lt,-ci:J::*~t.dl~~~:J:tJ: <. jiljf~
OJ!tfllc:*a- t.:~~Jlil':JfF.llr.~ll:l:~ t: Ghf.J:v'il; :!iMJi~W'lOJi:_,iJ;v' l:l: nA Gil'-c <!!> :Qo FolHlOJ 1:. 2: il~mWil C*9E~) IC .t Q jiljj~iJ>; 0) Dinophyceae, Acritarcha ~ Pediastrum 0) i[[,: /:B~;I;i)Lil>
G "i>xt;f~h""Cit~:QoliS FE! 'it'. eJJ

MAKIY AMA (1927 & 1931) correlated theTonohama to the Kakegawa group andconsidered them to be lower Pliocene inage. OTUKA (1932) correlated the Takanabe, Tonohama and lower Kakegawa
groups with each other, and concluded
the age as early Pliocene. ASANO (1936& 1937) studied the foraminifera of the
Tonohama group and considered it to be
the Pliocene. From the molluscan fossilsof the group, NOMURA (1937) concluded
it to be the lower part of the Pliocene.
Those investigators supposedly dealt
with the present-day Ananai formationof the Tonohama group.
KATTO, NAKAMURA and TAKAYANAGI(1953) published a paper on the strati-

Introduction
Along the east coast of the Tosa Bay,
Shikoku, Japan, the Pliocene called theTonohama group is scattered in a very
limited geographical extent.
In the history of research on the group,
0TSUKI (1904) presented a 1/200,000 geological map" Muroto Misaki" and SUZUKI(1929) published a 1/75,000 geological map"Muroto" both with explanations. YoKOYAMA (1926 & 1929) described the molluscan fossils from this group and considered its geological age to be Pliocene.
*Received Sept. 1, 1970; read Jan. 19, 1970
at Sendai.

143

144

Shiro NISHIDA

graphy and paleontology of the Tonohama group. They divided it into threeformations, which were the Ananai,
Nahari and Nobori formations, descending.Jy. According to KATTO et al. (1953),
these forma,tions are conformable with
one another, and the Ananai is a marine
formation, the Nahari is non-marine andthe Nobori is a marine formation. On
the geologic ages they concluded fromthe foraminiferal evidence that the Ananai and the NobJri formations are early
Pliocene and earliest Pliocene in age, respectively. But they pointed out that theforaminiferal ass()mblage of the Nobori
formation resemble3 those of the Miocene
deposits of the Kar Nicobar Islands in
the Indian Ocean. KA TTO and OZAKI(1955) concluded from the view point of
the molluscan and pollen fossils that theNobori is Miocene and the Ananai islower Pliocene in age. They also concluded that the Nobori formation is covered by the Nahari and Ananai formations unconformably and should be separable from the Tonohama group. After
that, KATTO (1960) renamed the Nahari
as the Ropponmatsu formation and heconsidered that the Nobori is Miocene
and the Ropponmatsu and Ananai are
Pliocene in age. From the molluscan
species TsucHI (1961) concluded that theNobori and Ananai formations should be
included in a single sedimentary groupof which geologic age is middle Pliocene.
From the planktonic foraminiferal evidence TAKA YANAGI and SAITO (1962)
correlated the Nobori formation with the
Globorotalia cultrata cultrataj Globigerina
nepenthes Zone of Venezuela and also
correlated with the type Tortonian of
Italy. SAITO (1963) correlated the Nobori
formation with Globigerina nepenthes
Zone. AOKI (1966) pointed out a possibility of being early Pliocene age for theNobori formation from detailed mollus-

can fossil studies. From the benthonicand planktonic foraminiferal evidence,
UCHIO (1967) considered that the Nobori
formation is probably earliest or early
Pliocene in age and the Ananai formation is early or middle Pliocene in age.
KURIHARA (1968) revised the stratigraphic
relationship of the Tonohama group,
namely, the Nobori and Ropponmatsu
formations are disconformable, and the
Ropponmatsu and Ananai formations areconformable. He concluded that the Nobori and Ananai benthonic foraminifera
belong to the same faunal group andthere is no significant unconformities
in the Tonohama group. He also statedthat the Nobori formation is regarded
to be lower Pliocene in age. TAKAYAMA(1969) compared the discoaster evidencewith the type of Italy and suggested that
the Nobori formation can be correlative
to medial or upper Pliocene in age.
The present author investigated thecalcareous nannoplankton fossils fromthe Tonohama group and found thirtyone species of calcareous nannoplankton
fossils including a new species by optical and electron microscopes. The geologic age was considered from the pointof view of calcareous nannoplankton
fossils.

Acknowledgement

The present author wishes to express
his sincere thanks to Professor Misaburo
SHIMAKURA of Nara University of Education for his constant encouragement
and valuable suggestions. Thanks arealso due to Mr. Kazumi MATSUOKA for
the field work with him. He received
valuable suggestions from Dr. Toshiaki
TAKAYAMA of Tohoku University. This
research was supported by a grant from
the Ministry of Education, Japan.

583.

Nannoplankton from the Tonohama group

Samples studied

According to KURIHARA (1968) thestratigraphic succession of the Tonohama group is concluded as follows indescending order ;Ananai formation: 25-65 m. Fine grainedsandstone with abundant molluscs andforaminifers. The lower part consistsof coarse- to medium-grained sandstone
with basal conglomerates.
· · · · .... conformity ....... .
Ropponmatsu formation: 15-70 m. Non-marine conglomerate consisting of poorly
sorted, subangular cobbles, often boulders at the base. Intercalated with thinlignite and lignitic siltstone beds.
· · · ·.. disconformity ..... .
Nobori formation: About 140m. Massive
siltstone. In the basal part coarse·- tofine-grained sandstone, alternating withsiltstone at some places. Abundant foraminifers and molluscs. Rarely foundshark's teeth, otoliths and vertebratebones.

Locality map of samples is shown m
Text-fig. 1.

MUROTO·MISAKIPACIFIC
OCEAN
I
134•

Text-fig. 1.

0

10

145

KC-2, 5, 8, 10: Nobori formation. Oso, Hane,
Muroto City. Gray siltstone.
KC-12, 15, 16, 18, 20, 22, 23, 25, 28, 30, 32:
Nobori formation. A quarry of Hane
Industry Co., Nobori, Hane, Muroto City.
Gray mudstone, siltstone and very finegrained sandstone.
KC-33, 34, 35: Nobori formation. Nishihama,Hane, Muroto City. Gray siltstone.
KC-37, 40, 41, 13: Nobori formation. A ruinof quarry, Nishitani, Hane, Muroto City.
Gray siltstone.
KC-45: Nobori formation. Nishitani, Hane,
Muroto City. Gray siltstone.
KC-49, 50, 51, 53, 54, 55: Ananai formation.
Higashitani, Tonohama, Yasuda-cho, Akigun, Kochi Pref. Medium-grained sandstone.
KC-57, 58, 59: Ananai formation. loki, Aki
City. Medium-grained sandstone.
KC-60: Ananai formation. loki cave, loki,
Aki City. Medium-grained sandstone.
KC-64, 66, 72, 73: Ananai formation. Shioya, Aki City. Medium-grained sandstone.

Method of the preparation was thesame as in the previous paper (NISHIDA,
1969).
Electronmicrographs were taken using
the Japan Electron Optics JEM-SS electron-microscope at an· accelerating voltage of 30 k V and a filament current of 60
rnA. Because the specimen itself was destroyed in the course of preparation, thetype specimens described in this article
are substituted by electronmicrographed
negatives. Serial numbers were given
to them. The negative films were deposited in Department of Earth Science,
Nara University of Education, Nara,
Japan.

20km

Sample locality map.

The stratigraphic unit, location andthe lithology for each sample are given
below;

Nannofossil assemblage and discussion

Occurrence of nannofossils in eachsample is shown in Table 1. This
table roughly shows the relative presentation in quantity. Each letter in theTable l.
I~

s~

Rock

Unit

MUROTO

Sample No.

fC. off. C. tricornicu/afus Gartnerffc c a c a c

Coccolilhus p8/agicus (Walllch)

a
f

f

f

s

Cyclococcollfhus !eploporus (Murray S Blackman)

a

c c

a

c c a

f

sp.C

s s f

f

f

brouweri Ton Sin Hok (4roys)D.

brouweri Ton Sin Hok (5rays)D.

brouwerl Tan Sin Hok (Grays)D.

challenged Bramlette S RiedelD.

dilalus Hay

D.

kug/eri Martini S BramletterD.

pentarodiafus Tan Sin Hok

c c f

D.

sfellulus Gartner

f

c c a
c a c cc c f c
s
f

f

f

f

c c c

s s

c c c
s

f

c c

f

f

s f

f

s f

s

s

f

s

s

f
f

s .f

f

f

s

c c

f

c c c c

c c
f

f

c c c
f

c c c

c a

f

f

s s s

f

f

s s

s

c c c c cfc cc c c c c c ffr

c c c c s s s c c c c c c c c c
s
f
f s s
s s s
f f s
s

f
f

f
a
a

f

f

f

c c c c c c c c c c c c c
c c c c c a c c c c f c c
c c f c f c c c c c c f c c
s
s
s

f

f

c

f

c c c
f

f

s

c c c af
f

f

s s s s f
s s

f

f

r

r

r

r

~

r
r

r

r

~-

r

0

~
(/)

f

c f

s

f

f

f

f

f

s

s
s

s

f

s

r

r

f

f

f

s

r

~

r

~

r
r
r

f

f

f

r

c c a c c a c
c c c a a c c cs
c c f f f c c c
s
s
f s s

a

Helicopontosphaera kamplneri Hoy 8 Mohler
Ponfosphaera discopora SchillerfRhabdosphaera cfav/ger Murray S Blackman

c c c a c c c c c
c c c c c c c c css c c c f f a a a fc a c c c c c c c
c c c c c c c a c c

a

a

f

s f

c c s s c c
s f
f

f

s

f

r

f

Scyphosphaera apsteini Lohmann

f

f

f

f
f

r

r

c c c c c c c c c
c c c c c c c c c ffac c c c f

s s

r

f

r

f

f

f

f
f

Syracsphaera pulchra Lohmann
Umbilic_o_sphaert:J_ ___cricota {Gartner)

c c c

r

c c c c ccEmlllanio huxley/ (Lohmann)japonica {Takayama)

f

f

r

s

s

Gephyrocapsa reficu/ala Nishida n. sp.

vadosa Hay, Mohler 8 Wadefc f a a cc c c c fc c c c cssf

E/1/psop/aco/ilhus producfuc Kamptner

P.

c c c
s

r

f

D.

P.

AN ANAl

lOKI

f

r

s

s f

r

Discoasfer brouwerl Ton Sin Hok (3roys)

surcu/us Martini 8 Bramlette

s

f

f

s

Dlscolilhlna sp. B

toni Bramlette S Riedel

FORMATION

TONOHAMA

HANE
f

f
f

Cricolithus sp.

D.

"""
"'

2 5 8 10 12 15 16 18 20 222325283032 33 34 35 37404143 45 4950 51 53 54 55 57 585960 64667273
s r s f r s s r f s r rf

Cerafolithus crlsfus Kamptner

D.

ANANAIFORMATIONNOBORI

Location

Braarudosphaera bfgelowi (Gran 8 Braarud)D.

......

Distribution of calcareous nannoplankton fossils from the Tonohama group.

-s ___ fr' rorerrs

f' fews' severo I

f

r

s

r

C' commonsfso' abundant

f

r

f

r

583.

Nannoplankton from the Tonohama grouptable denotes as follows; r: represents
rare, f : a few, s : several, c : common anda: abundant. Bold letters of the sample
number, such as KC-5, 8, 12, 15, 18, 20,
23, 25, 28, 30, 32, 34,37, 40, 43, 45,50,51,54,
55, 59, 60 and 66, represent results by theelectronmicroscopical observation. Results by the optical microscope are shownin thin letters, such as KC-2, 10, 16, 22,
33, 35, 41, 49, 53, 57, 58, 64, 72 and 73.
Throughout all samples, predominant
species are Coccolithus pelagicus (W ALLICH), Gephyrocapsa reticulata n. sp.,
Cyclococcolithus leptoporus (MURRAY &BLACKMAN), Helicopontosphaera kamptneri and Pontosphaera japonica (TAKAYAMA). In the Nobori formation, besides
the above mentioned species, Discoasterbrouweri, D. challengeri, D. pentaradiatus
and D. surculus are common. Especially
5-rayed Discoaster brouweri is representative. On the contrary, in the Ananai
formation discoasters are meager andoccur sporadically. Discoasters in the
Ananai formation are not considered to
be derived fossils judged from its stateof preservation.
In the N obori formation, Discoasterpentaradiatus, D. brouweri, D. surculus,
Cyclococcolithus leptoporus (MURRAY &BLACKMAN), Helicopontosphaera kamptneri, Coccolithus pelagicus (W ALLICH),
Gephyrocapsa reticulata n. sp. and Pontosphaera japonica (TAKAYAMA) occur generally, and Scyphosphaera apsteini and
Ceratolithus cristus occur sporadically.
It may not be ignored that Discoaster
dilatus, D. kugleri, D. stellulus, D. taniand Ceratolithus aff. C. tricorniculatus occur in considerable amount from this formation. They are common in the Miocene
strata. Also Pleistocene species such as
Ceratolithus cristus, Ellipsoplacolithus productus, Emiliania huxleyi (LOHMANN) andSyracosphaera pulchra occur sporadicallyin this formation. Supposedly the strati-147

graphic ranges of these species will dateback to Pliocene in age.
In the Ananai formation Discoasterpentaradiatus, D. brouweri, Cyclococcolithus leptoporus (MURRAY & BLACKMAN),
Helicopontosphaera kamptneri, Coccolithus
pelagicus (W ALLICH), Pontosphaera japonica (TAKAYAMA) and Gephyrocapsa reticulata n. sp. occur abundantly, and also
they are all representative species in theNobori formation. The occurrence ofBraarudosphaera bigelowi (GRAN & BRAARUD) is restricted in the Ananai formation. The occurrence of discoasters
is less common in the Ananai formation
than in the Nobori formation.
Some biostratigraphers who deal withcalcareous nannoplankton fossils emphasize the morphological change observed in number of rays of Discoasterbrouweri. Recently, TAKAYAMA (1969)
reported discoaster evidences from theLamont Core V21-98 and from the Nobori formation. He examined the morphological variation of D. brouweri andpresented relative frequencies of the
discoasters. But he found no conspicuous morphological changes of D. brouweri in the Nobori formation. In theLamont Core V21-98, he recognized gradual changes in the morphology of D.
brouweri except 9-rayed form. From the
N obori formation the present author
found 3, 4, 5 and 6-rayed forms of D.
brouweri. Among them, representative
forms are 5 and 6-rayed. In the Ananai
formation 5 and 6-rayed forms of D.
brouweri occur sporadically. In both formations no conspicuous morphologicalchanges of D. brouweri are recognizedstratigraphically.
From the Nobori and Ananai formations, molluscs, benthonic and planktonic foraminifera, shark teeth andpollen fossils are found by many investigators. MATSUOKA (personal com-

148

Shiro NISHIDA

munication) recently recognized many
interesting plant microfossils, such as
Dinophyceae and Acritarcha, from bothformations. He found Hystricosphaerasp., Leptodinium sp. and Nematosphaeropsis sp. as Dinophyceae, Baltispheridium sp. and Cymatiosphaera sp. as
Acritarcha and some other indeterminable species, and could not recognize
any evident floral changes in both formations. Quantitatively, they occur
abundantly in the Ananai but less in theNobori formations. He found also somespecimens of Pediastrum spp. (delicate
fresh-water green algae) from the Nobori
formation.
The calcareous nannoplankton fossil
evidence suggests that there is no significant difference between the geologic
ages of the Ananai and Nobori formations, and that there is a considerable
difference in the environmental condition
between the two formations. The evident
occurrence of discoasters in the Nobori
formation and the restricted occurrenceof Braarudosphaera bigelowi (GRAN &BRAARUD) in the Ananai formation suggest the difference in the sedimentary
environment between the two formations.
The occurrence of plant microfossils
such as Dinophyceae and Acritarcha gives
positive support to this _conclusion. The
occurrence of Pediastrum spp. from theNobori formation indicates that the formation is not necessarily pelagic or offshore sediment.
On the geologic age of the Nobori
formation the present author correlates
it to the Discoaster surculus Zone in Italy
which is proposed by HAY & SCHMIDT(1967), because of a few or several
occurrences of Discoaster surculus fromthe all samples treated. And he correlates the Ananai formation to the Discoaster extensus Zone or Discoaster brouweri Zone, both of the Submarex Holeon the Nicaragua Rise, because of thesporadical occurrences of Discoasterpentaradiatus and D. brouweri. BRAMLETTE and WILCOXON (1967) correlated
the middle. Tertiary calcareous nannoplankton of the Cipero section, Trinidad
with the foraminiferal zones of BOLLI.
They dealt the Eocene, Oligocene andMiocene sections. A comparison with
their calcareous nannoplankton range
chart does not result in any useful time
markers in the present assemblages.
This fact may indicate the possibility
that the Nobori formation is the Pliocene in age. Recently, MARTINI andWORSLEY (1970) proposed a standard
Neogene calcareous nannoplankton zonation. According to them, the Nobori
formation is correlated with their NN16,
that is, Discoaster surculus Zone or atleast lower than it, by the reason ofcommon· occurrence of Discoaster pentaradiatus and the several or a few occurrences of Discoaster surculus. The Ananai formation is correlated with their
NN18 or NN17 Zone, that is, Discoasterbrouweri Zone or Discoaster pentaradiatus
Zone, by the reason of the rare occurrences of Discoaster brouweri and Discoaster pentaradiatus. The present author, considering the Neogene calcareous
nannoplankton flora in Japan, proposes
earliest or early Pliocene for the age ofNobori formation and early or middle
Pliocene for the age of Ananai formation.
The reason is that the present author
does not ignore occurrences of some
Miocene species in considerable amount,such as Discoaster dilatus, D. kugleri, D.
stellulus, D. tani and Ceratolithus aff. C.
tricorniculatus from the Nobori formation.

Systematic description

Genus Coccolithus ScHWARTZ, 1894

583.

Nannoplankton from the Tonohama grmtp

149

Coccolithus pelagicus (W ALLICH)

Cyclococcolithus leptoporus (MURRAYSCHILLER, 1930

& BLACKMAN) KAMPTNER, 1954

Pl. 17, Figs. 12-15

Pl. 16, Figs. 1-4

Coccosphaera pelagica W ALLICI-I, 1877, p. 348,
pl. 17, fig. 5.
Coccolith us pelagicus (W ALLICI-1) ScHILLER;
MciNTYRE & BE, 1967, pp. 569-570, pl. 8,
figs. A-C.

Coccosphaera leptopora MuRRAY & BLACK·
1\!AN, 1898, pp. 430-437 & 439, pl. 15, figs.
1-7.
Coccolithophora leptopora (MURRAY & BLACK·:\!AN) LOH:\!ANN, 1902, pp. 137-138, pl. 5,
fig. 52.
Coccolithus leptoporus (MuRRAY & BLACK·MAN) ScHILLER ; BLACK & BARNEs, 1961,
p. 143, pl. 24, figs. 3-4.
U mbilicosphaera leptopora (MURRAY & BLACK·MAN) COHEK & REINHARDT, 1968, p. 296,
pl. 20, fig. 11.
Coccolithus leptoporus (MuRRAY & BLACK·MAN) KA:VIPTNER var., A, MciNTYRE etal., 1967, pp. 9-10, pl. 4, figs. C-D.
Cyclococcolithus leptoporus (MURRAY &BLACK·:\·!AI\) KA:\!PTNER, 1954, p. 23, fig. 20;
COHEN, 1964, p. 237, pl. 2, fig. 4.

Description: Placolith, oval in planeview with wide shields convex distally,·Concave proximally and a narrow ellipti··cal central pore. In the distal view the·outer elements have radial suture with-dextral imbrication. In the center anumber of rhomboidal elements arranged
helically. The proximal shield is smaller-and the fine sutures incline dextrally.
Normally there is a bar made of rhom·bic elements that crosses the pore at its·Center making a right angle with thelong axis of the pore.
The length of the distal shield of the
hypotypes ranges from 9 p to 11 p. The
width ranges from 7 f-1- to 8 p.
Hypotype: PI. 17, Figs. 12-15. (12; KC
18R-3, 13; KC54R-13, .14; KC60R-29, 15;
KC54R-9).

Genus Cricolithus KAMPTNER, 1958
Cricolithus sp.
Pl. 16, Fig. 15

Description: Placolith, circular in planeview with wide ring-like shields and awide central pore. Rhombic calcite segments radiate and imbricate dextrally.
Diameter of the shield is 6 p and diameter of the central pore is 3 p. Width·Of the shield is 1.5 p.
Hypotype: Pl. 16, Fig. 15. (KC18R-49).

Description: Placolith, circular in planeview with symmetrical shields convex
distally and concave proximally. Segments petaloid with dextral imbricationin the distal shield and sinistral in theproximal shield. A central pore open.
Segments are counted about forty mnumber.
The diameter of the distal shield of
the hypotype ranges from 10 p to 14 p.
The proximal shield is about 10 p. The
diameter of the central pore is approximately 2 p.
Hypotype: PI. 16, Figs. 1-4. (1; KC18
R-40, 2; KC25R-24, 3; KC12R-6, 4; KC
18R-4).

Genus Discolithina LOEBLICH& TAPPAN, 1963
Discolithina sp. A
Pl. 16, Fig. 7

Genus Cyclococcotithus KAMPTNER, 1954

Description:

Disco lith,ellipticalmShiro NISHIDA

150

plane view with a narrow rim and awide central area. The rim is composedof fine rhomboidal elements arranged
radially. The central area is completely
infilled with fine calcite crystals arranged
in a slightly rotated pattern.
Length of this specimen is supposed tobe more than 20 f.!.·Hypotype: Pl. 16, Fig. 7. (KC18R-28).
Discolithina sp. B
Pl. 17, Fig. 16

Description: Discolith, elliptical inplane view with a thick and wide rim,and perforated central area. In thecentral area perforation is arranged in
4 to 7 rows on a side of the longitudinal
central fissure.
Length of this specimen is approximately 6 f.l-·
Hypotype: Pl. 17, Fig. 16. (KC20R-44).
Discolithina sp. C

Description: Placolith, elliptical irr
plane view with shields convex distally,
concave proximally. Segment petaloi<fwith' slightly sinistral imbrication in theproximal shield at the view from the·proximal side. Central longitudinal slit·
is conspicuous.
The longitudinal diameter of the distal shield ranges from 3 f.l- to 5 f.l-·
Hypotype: Pl. 17, Figs. 9-11. (9; KC'
12R-19, 10; KC43R-5; 11; KC12R-52).

Genus Emiliania HAY & MOHLER, 1967"
Emiliania huxleyi (LOHMANN)

HAY & MOHLER, 1967
Pl. 17, Fig. 6

Pontosphaera huxleyi LOHMANN, 1902, pp. 129130, pl. 4, figs. 1-9 & pl. 6, fig. 69.
Coccolithus huxleyi (LoHMANN) KAMPTNER ;·KAMPTNER, 1952, p. 234, fig. 10; BRAARUD·et al., 1952, pp. 129-131, text-fig. 3, pl. 1,
figs. a-f.
Emiliania huxleyi (LoHMANN) HAY & MoHLER, 1967, p. 447, pls. 10-11, figs. 1-2.

Pl. 16, Fig. 9

Description: Elliptical disc, with distinct flat rim and uneven central area.
Length of this specimen is approximately 8p.
Present specimen differs from Pontosphaera japonica (TAKAYAMA) in numerous perforated pores, longitudinal central
fissure and dimension.
Hypotype: Pl. 16, Fig. 9. (KC15R-47).

Genus Ellipsoplacolithus KAMPTNER, 1963
Ellipsoplacolithus productus

Description: Placolith, oval in plane·view with shields equal in size, convex,.
distally and concave proximally. Largeelliptical pore. The T-shaped segments·.
from both shields in present specimen..
The end of each element slightly interlocked. Frorri the morphology of elements in the proximal shield, the present·
specimen seems to be warm water·
species.
The length of the hypotype is 3.5 f.!.·Hypotype: Pl. 17, Fig. 6. (KC18R-2).

Genus Gephyrocapsa KAMPTNER, 1943

KAMPTNER, 1963
Gephyrocapsa reticulata NISHIDA, n. sp ..
Pi. 17, Figs. 9-11
Pl. 17, Figs. 1-3

Ellipsoplacolithus productus KAMPTNER, 1963,
pp. 172-173, pl. 8, figs. 42 & 44.

Remarks:

Elliptical placolith with a?.

583.

Nannoplankton from the Tonohama group

Text.fig. 2.
Left: Distal view.

151

Gephyrocapsa reticula/a NISHIDA n. sp.
Right: Proximal view.

'chest-bone-shaped structure in the central opening.
Description:
Placolith, elliptical inplane view with closely appressedshields convex distally, concave proximally and a conspicuous chest-boneshaped structure in the central opening.
The distal shield larger than the proximal one, composed of about fifty-fivesegments which imbricate slightly dextrally. Outer margin indentate. Smaller
proximal shield is composed of the same
number of segments which imbricate
sinistrally. The chest-bone-shaped structure in the central pore is composed of.a central longitudinal bar and ten to
fifteen limbs in a side which branch out
from the central bar, and some limbs
branch out again at outer ends.
The length of the distal shield ranges
from 5 f-1 to 6 f-1· The length of theproximal shield is approximately 4 f-1·
The length of the central opening ranges
from 1.5 f-1 to 2 fl.
The present new species has been
elected on the basis of its dimensional

Scale bar 1 micron.

and constructional differences from described species which belong to the same
genus. The present species differs distinctly from Gephyrocapsa aperta, G.
caribbeanica, G. ericsoni and G. oceanica
in having a bridge structure on thecentral pore. This species differs also
from G. lwmptneri in its dimension of
the shield and in the number of segments. The figure presented as Cyclococcolithus sp. aff. C. dictyodus (DEFLANDRE and FERT) by BARTOLINI (1970)
resembles this species but differs on
the chest-bone structure in the central
pore, especially in having the central
longitudinal bar.
Holotype: PI. 17, Fig. 2. (KC18R-1).
Paratype: PI. 17, Figs. 1 & 3. (1; KC
18R-51, 3; KC18R-22).
Gephyrocapsa sp.
Pl. 16, Fig. 13

Description: Placolith, elliptical inplane view with closely appressed152

Shi1·o N ISHID A

shields convex distall y and concave
proxim ally. Indentated outer marg in in
both shield s. Th e centra l area is covered. T he number of segments is about
fort y in each shield .
The leng th of the specimen is 5 f-1·
HyjJotyjJe · Pl. 16, Fig. 13. (KC15R- 48).
Genus Helicopontosp!wera HAY

and lamellar rim which gentl y t wists
dextrall y throu ghout .
Length of th e h ypot ype is a pprox imately 9.0 f-l · Length of the central areais 6.5 f-l and width of the rim is about
2.0 f-l· Diameter of the perforation isapproximately 0.5 f-l·
HypotyjJe : Pl. 17, Figs. 7-8. (7; KC5R71, 8; KC40R- 12).

& MOHL ER, 1967

PontosjJhaera ja ponica (T AKAYAMA)
HelicojJontosphaera lwmptneri HAY& MOHLER, 1967
P l. 17, F igs. 17- 18

Coccolithus carteri ( vV A LLI C I-1) I):AMP T NE R,
1941, p. 93, pl. 8, figs. 134- 136.
H e!icosphaera carteri ( W A LL ICI-1) K AiVIPTNER,
1954, p. 22, figs . 17- 19; BLACK & B A R N ES ,1961, p . 139, pl. 22, fig. 1 & pl. 23, figs .
1- 2.
H elicopon t osphaera kamjJtn eri H AY & M oHLER,
1967, p . 448, pis . 10- ll, fi g . 5.

DescrijJtion: This species is describedthoroughl y b y BL ACK & BARNES (1961)
w ith excell ent fi g ures. Both perfor ate
and imperforate specimens occur in thesame sample.
Len gth of the h y pot ype ranges approx imately f rom 7 f-l to 10 f-l ·HypotyjJe: Pl. 17, F igs. 17- 18. (17; KC
15R-62, 18 ; KC37R - 12).
Genus Pontosphaera LOHMANN, 1902

Pontosphaera alboranensis
BARTOLI NI, 1970

P l. 16, F igs. 10- 11

D iscoht hina millepuncta G A RT NE R, 1967, p. 5,
pl. 8, figs . 1- 2.
D1:scolithina jajJonica T AKA Y AMA , 1967, pp.
189- 190, pl. 9 & pl. 10, fi g . 1.

DescrijJlion : Lopadolith, elliptical withfla t rim and long itudinal central fissure.
Numerous perforations in the central
disc.
Length of the h y potype ranges approx imately from 12 f-l to 15 f-l· Widthof the rims ran ges from 2.5 f-l to 4.0 f-1Diameter of the pore in the central area
is 0.1 f-l·
Electronmicrogr aphs of the present
species ar e presented as Pontosphaera
japonica (TAKAYAMA) in figures 9 and
10 of "Atlas of Japanese Fossils" No.
6- 31 (HON JO & OKA DA, 1969) with a brief
description and in a plate in " Koseibutsugaku -NyO.mon " (meanin g Introduction
to Paleontology in Japanese, ASANO,
1969) without description .
Hypotype: Pl. 16, Fi gs. 10- 11. (10; KC
60R- 17, 11 ; KC50R - 13).

P l. 17, F igs. 7- 8

Pontosphaera s p., H A Y et al., 1967, pis. 10- 11,
fig . 6.
Pon tosphaera alb oranen sis B A R TO LI N 1, 1970,
pp . 148- 150, pl. 6, figs. 6- 7, te xt -fi g . 9.

Pontosphaera cf . P. vadosa HAY,
MOHLER & WADE, 1966

Descri}Jtion: Lopadolith, elliptical withwid e, flat and perforated central area

Pon tosphaera vadosa H A Y, M oHLER & W A DE,
1966, p . 391, pl. 8, fig. 4.

P l. 16, Fi gs. 8 & 12

583.

Nannoplankton from the Tonohama group

Discolithina sp., TAKAYAMA, 1967, p. 191, pl.
1, fig. 7 & pl. 3, figs, 1-19.

Description: Lopadolith, elliptical withslightly concave central area in proximal view. Longitudinal central fissurein the central area.
Length of the hypotype is approximately 11 f.l·Present specimen differs from Pontosphaera vadosa in the number of perforations.
Hypotype: Pl. 16, Figs. 8 & 12. (8;KC25R-6, 12; KC15R-81).

153

133-134, pl. 4, figs. 33 & 36-37; DEFLANDRE& FERT, 1954, pl. 5, figs. 1 & 4-5.
Syracosphaera sp., CoHEN, 1.965, p. 20, pl. 25,
fig. f.

Description: Discolith, nearly ellipticalwith narrow, thick double marginal
rings. Large central area with radialribs. The radial ribs are seen to bearranged in bundles or sieves, overlapping to some extent at the center.
Length of the hypotype is approximately 3 fl.
Hypotype: (KC15R-51).

Pontosphaera sp.

Genus Umbilicosp!wera LOHMANN, 1902

PI. 16, Figs. 5-6

Umbilicosphaera cricota (GARTNER)

Description: Lopadolith, elliptical with

COHEN & REINHARDT, 1968

a distinct wide rim and perforated fiat
central area. On the rim fine striae
wind sinistrally or dextrally in a specimen. Perforated holes in the central
area arrange regularly.
Length of the hypotype is approximately 13 f.l· Length of the central areais 10.5 f.1 and width of the rim is 2 f.l·Diameter of the perforation is approximately 0.5 f.l·Present specimen somewhat resembles
Discolithina distincta but differs in thenumber of holes, and resembles thefigure shown as Discolithus sp. 1 by
SALES (1967). Both figures of Discolithina
distincta and Discolithus sp. 1, to which
the present author referred, are optical
micrographs. Electronmicrographs ofthe species are wanted.
Hypotype: Pl. 16, Figs. 5-6. (5; KC15R80, 6; KC18R-18).

Pl. 17, Figs. 4-5

Genus Syracosphaera LOHMANN, 1902

Syracosphaera pulchra LOHMANN, 1902
Syracosphaera pulchra LoHMANN, 1902, pp.

Ellipsoplacolithus lacunosus KAMPT:-;ER, 1963,
p. 172, pl. 9, fig. 50.
Ellipsoplacolithus exsectus KAMPTNER, 1963,
p. 171, pl. 9, figs. 51-52.
Coccolithus doronicoides BLACK & BARNES,
MciNTYRE et at., 1967, pl. 3, fig. A.
Cyclococcolithus cricotus GARTNER, 1967, p. 5,
pl. 7, figs. 5-6.
Umbilicosphaera cricota (GARTNER) CoHEN &REINHARDT, 1968, p. 296, pl. 21, fig. 3.

Description: Placolith, circular inplane view with large shields convex
distally, concave proximally and a wide
central pore. In the larger distal shield,
T -shaped segments radiate from theinner ring and make the pencil-shaped
opening between them. Proximal shieldis narrow in width, and composed ofnarrow and short segments arranged
without space.
Diameter of the hypotype is approximately 4.5 f.l· Diameter of the central
opening is 2 f.l· Width of the distal
shield is 1.2 f.l·
Hypotype: Pl. 17, Figs. 4-5. (4; KC55R-

Shiro NISHIDA

154
9, 5; KC43R-14).

Genus Discoaster TAN SIN HoK, 1927
Discoaster brouweri TAN SIN HOK, 1927
Pl. 18, Figs. 7 & 9
Discoaster brouweri TAN SIN HoK ; sens
emend., BRAMLETTE & RIEDEL, 1954, p.
402, pl. 39, fig. 12.

Description: Asterolith with 3, 4, 5
or 6 long slender and gently curved
rays. 5 and 6 rayed forms are common
in both the Nobori and Ananai formations.
Length of the hypotype .ranges from
7 p. to 11 p..
Hypotype: PI. 18, Figs. 7 & 9. (7 ; KC
25R-48, 9; KC18R-52).

distally bifurcated into short, roundterminations. Widening of the rays in
the central area is not pronounced. In
the central area there is a small, circular knob.
Dimension of the hypotype is approximately 12 p..
Hypotype: (KC15R-66).
Discoaster dilatus HAY, 1967
Pl. 18, Fig. 2
Discoaster dilatus HAY, 1967, pp. 450-451, pl.
4, figs. 3-4.

Description: Asterolith with 6 broad
flaring, flatly terminated rays.
Length of the hypotype is approximately 14 p..
Hypotype: PI. 18, Fig. 2. (KC20R-34).

Discoaster brouweri TAN SIN HoK

Discoaster kugleri MARTINI

rutellus GARTNER, 1967

& BRAMLETTE, 1963

Pl. 18, Figs. 5 & 8

Pl. 18, Fig. 1

Discoaste1· brouweri TAN SIN HoK rutellus
GARTNER, 1967, p. 2, pl. 1, figs. 1-2.

Discoaster kugleri MARTINI & BRAMLETTE,
1963, p. 853, pl. 102, figs. 11-13.

Description: Asterolith, with 6 slenderand gently curved rays. Rays sharply
bent near the end and extend like broad
blade.
Dimension of the hypotype ranges
approximately from 11 p. to 15 p..
Hypotype: PI. 18, Figs. 5 & 8. (5 ; KC
20R-39, 8; KC45R-36).

Description: Asterolith, with 6 shortbluntly terminated rays, and a large
and flat central area. In the central
area a small knob and a ridge are observable.
Dimension of the hypotype is approximately 14 p..
Hypotype: PI. 18, Fig.. 1. (KC8R -15).

Discoaster challengeri BRAMLETTE& RIEDEL, 1954

Discoaster pentaradiatus

Discoaster challengeri BRAMLETTE & RIEDEL,
1.954, p. 401., pl. 39, fig. 10.

PI. 18, Figs. 3, 6 & 13-14

Description: Asterolith, with 5 or 6
long rays which are subcylindrical and

TAN SIN HOK, 1927

Discoaster pentaradiatus TAN SIN HoK; sens
emend., BRAMLETTE & RIEDEL, 1954, pp.
401-402, pl. 39, fig. 11, text-fig. 2.

583.

Nannoplankton from the Tonohama group

Description: Asterolith, with 5, rarely
6, thin bifurcated rays. Bifurcated ends
are sharp and delicate. Interray margin
curves round and smoothly.
Dimension of the hypotype ranges
from 12 f1 to 17 fl·
Hypotype: Pl. 18, Figs. 3, 6 & 13-14.
(3; KC43R-35, 6; KC23R-11, 13; KC25R36, 14; KC12R-5).

Discoaster stellulus GARTNER, 1967
Pl. 18, Figs. 10-11

Discoaster stellulus GARTNER, 1967, p. 3, pl.
4, figs. 1-2.

Description: Asterolith, with 6 short,round-end rays. A prominent parallelridge on the surface of each ray.
Dimension of the hypotype is approximately 5 fl·
Hypotype: Pl. 18, Figs. 10-11. (10; KC
20R-43, 11; KC15R-63).

Discoaster surculus MARTINI& BRAMLETTE, 1963
Pl. 18, Fig. 4

Dis coaster brouweri TAN SIN HoK; STRADNER& P APP, 1961, pl. 20, figs. 2 & 3.
Discoaster surculus MARTINI & BRAl\ILETTE,
1963, p. 854, pl. 104, figs. 10-12.

Description: Asterolith, with 6 rays.
Two short and small bifurcations on
both sides of each ray. A stellate knob
is observed in the middle of the central
area. From the knob thin ridges extend
along the rays. The end of the ray
makes a slight flare and a blunt termination.
Dimension of the hypotype is approximately 12 fl·
Hypotype: Pl. 18, Fig. 4. (KC32R-37).

155

Discoaster tani BRAMLETTE& RIEDEL, 1954
Pl. 18, Fig. 12

Discoaster tani BRAMLETTE & RIEDEL, 1954,
p. 397, pl. 39, fig. 1.

Description: Asterolith, with 6 rays.
Rays rather heavy and of almost uniform width, abruptly truncated.
Dimension of the hypotype is approximately 12 fl.
Hypotype: Pl. 18, Fig. 12. (KC15R-18).

Genus Braarudosphaera DEFLANDRE, 1947

Braarudosphaera bigelowi (GRAN &BRAARUD) DEFLANDRE, 1947
Pl. 16, Fig. 17

Pontosphaera Bigelowi GRAN & BRAARUD,
1935, pp. 388-389, text-fig. 67.
Braarudosphaera bigelowi (GRAN & BRAARUD)
DEFLANDRE, 1947, pp. 439-441, figs. 1-5.

Description: Pentalith formed by characteristic five segments.
Dimension of the hypotype is approximately 22 fl·
Hypotype: Pl. 16, Fig. 17. (Optical
micrograph KC49).

Genus Ceratolithus KAMPTNER, 1950

Ceratolithus cristus KAMPTNER, 1950
Ceratolithus cristus KAMPTi\:ER; DEFLANDRE,
1952, p. 468, figs. 44-45.

Description: Horseshoe-shaped small
calcareous body with pointed ends.
Dimension of the specimen ranges
from 4 f1 to 8 fl·
Hypotype: Undesignated.

Shiro NISHIDA

156

Ceratolithus aff. C. tricorniculatus
GARTNER, 1967
Pl. 16, Fig. 16
Ceratolithus tricorniculatus GARTNER, 1967, p.
5, pl. 10, figs. 4-6.

Description: Ceratolith, with two sym·
metrically curved horns of the same
thickness. A short horn projects on
the convex side of the specimen.
Length of the hypotype is approximately 17 fl.

Explanation of Plate 16
Electronmicrographs of carbon replica except figure 17.
The bar under figure 17 represents 10 microns.
Fig.

1.

Fig.

2.

Fig.

3.

Fig.

4.

Fig.

5.

Fig.

6.

Fig.

7.

Fig.

8.

Fig.

9.

Fig. 10.
Fig. 11.

Fig. 12.
Fig. 13.
Fig. 14.

Fig. 15.
Fig. 16.
Fig. 17.

Scale bar represents 5 microns.

Cyclococcolithus leptoporus (MURRAY & BLACKMAN) KAMPTNER
Distal view. KC18R-40. Nobori formation. Nobori, Hane, Muroto City.
Cyclococcolithus leptoporus (MURRAY & BLACKMAN) KAMPTNER
Proximal view. KC25R-24. Nobori formation. Nobori, Hane, Muroto City.
Cyclococcolithus /eptoporus (MURRAY & BLACKMAN) KAMPTNER
Proximal view of the distal shield. KC12R-6. Nobori formation. Nobori, Hane,.
Muroto City.
Cyclococcolithus leptoporus (MURRAY & BLACKMAN) KAMPTNER
Distal view. KC18R-4. Nobori formation. Nobori, Hane, Muroto City.
Pontosphaera sp.
KC15R-80. Nobori formation. Nobori, Hane, Muroto City.
Pontosphaera sp.
KC18R-18. Nobori formation. Nobori, Hane, Muroto City.
Discolithina sp. A
KC18R-28. Nobori formation. Nobori, Hane, Muroto City.
Pontosphaera cf. P. vadosa HAY, MoHLER & WADE
KC25R-6. Nobori formation. Nobori, Hane, Muroto City.
Discolithina sp. C
KC15R-47. Nobori formation. Nobori, Hane, Muroto City.
Pontosphaera japonica (TAKAYAMA)
KC60R-17. Ananai fo.rmation. loki, Aki City.
Pontosphaera japonica (TAKAYAMA)
KC50R-13. Ananai formation. Higashitani, Tonohama, Yasuda-cho, Aki-gun, Kochi
Pre f.
Pontosphaera cf. P. vadosa HAY, MoHLER & WADE
KC15R-81. Nobori formation. Nobori, Hane, Muroto City.
Gephyrocapsa sp.
KC15R-48. Nobori formation. Nobori, Hane, Muroto City.
? Thoracosphaera sp.
KC51-25. Ananai formation. Higashitani, Tonohama, Yasuda-cho, Aid-gun, Koehn
Pre f.
Cricolithus sp.
KC18R-49. Nobori formation. Nobori, Hane, Muroto City.
Ceratolithus aff. C. tricorniculatus GARTNER
KC18R-41. Nobori formation. Nobori, Hane, Muroto City.
Braarudosphaera bigelowi (GRAN & BRAARUD) DEFLAl\'DRE
Optical micrograph. KC4\:'. Ananai formation. Higashitani, Tonohama, Yasuda-ch6,.
Aki-gun, Kochi Pref.

NISHIDA : Nannoplanktons fr om Tonohama

5p

Plate 16

583.

Nannoplankton from the Tonohama group

Present specimen somewhat resembles

Ceratolithus tricorniculatus in the outershape but differs in length of the horn.
Hypotype: Pl. 16, Fig. 16. (KC18R-41).
Genus Rhabdosphaera HAECKEL, 1894

Rhabdosphaera claviger MUHRAY& BLACKMAN, 1898
Rhabdosphaera claviger MuRRAY & BLACK·
MAN, 1898, pl. 1.5, fig. 1.

Description: Specimen composed of aclub-shaped stem and a trumpet-likebasal part.
Dimension of the specimen is commonly 7 fl·
Hypotype: Undesignated.

Genus Scyphosphaera LOHMANN, 190.2

Scyp/wsphaera apsteini LOHMANN, 1902
Scyphosphaera apsteini LoHMANi\', 1902, p. 132,
pl. 4, figs. 26-30.

Description: Comparatively large beerbarrel-shaped lopadolith.
Height approximately 15 f1 and width
12 fl·• Hypo type: U ndesignated.

References
AOKI, N. (1966): Molluscan fossils from theNobori formation, Shikoku, Japan. Trans.
Proc. Palaeont. Soc. japan, N.S., 62, 251256, pl. 31.
AsANO, K. (1936) : New species of Foraminifera from Aki-gun, Tosa Province, Japan. jour. Geol. Soc. japan, 43, 942-946.
pis. 51-52.
- - (1937): A comparison of the Recent
Foraminifera from Tosa Bay and the Pliocene Foraminifera from Aki-gun, Province

157

of Tosa. Ibid., 44, 36-55. (in Japanese)- - (1969): Koseibutsugaku Nyumon (Introduction to Paleontology). Asakura Shoten, Tokyo. (in Japanese)
BARTOLINI, C. (1970): Coccoliths from sediments of the western Mediterranean.
Micropal., 16, 129-1.54, pis. 1-8.
BLACK, M. & BARNES, B. (1961): Coccoliths
and Discoasters from the floor of theSouth Atlantic Ocean. jour. Roy. Microscopic Soc., 80, 137-147.
BRAARUD, T., GAADER, K.R., MARKALI, J.
& NoR DLI, E. (1952) : Coccolithophorids
studied in the electron microscope. Observations on Coccolithus huxleyi andSyracosphaera carterae. Nytt Mag. Bot.,
1' 129-134, 1 pl.
BRA:VILETTE, M.N. & RIEDEL, W.R. (1954):
Stratigraphic value of discoaster andsome other microfossils related to recent
coccospheres. jour. Paleont., 28, 384-403,
pis. 38-39.
- - & WILCOXO:", J,A. (1967): Middle Tertiary calcareous nannoplankton of the
Cipero section, Trinidad, W.I. Tulane
Stud. Geol., 5, 93-131, incl. 10 pis.
ColiEi\', C.L.D. (1964):
Coccolithophorids
from two Caribbean deep-sea cores.
Micropal., 10, 231-250, pis. 1-6.
- - (1965) : Coccoliths and discoasters from
Adriatic bottom sediments. Leid. Geol.
Meded., 35, 1-44, pis. 1-25.
- - & REINHARDT, P. (1968): Coccolithophorids from the Pleistocene Caribbean
deep-sea core CP-28. N. ]b. Geol. Paliiont. A/Jh., 131, 289-304, pis. 1.9-21.
DEFLAi\'DRE, G. (1947):
Braarudosp/wera
nov. gen., tyoe d'une famille nouvelle deCoccolithophoridees actuels
element
composites. Acad. Sc£., C.R., 225, 439441.
- - (1952): Cla;:;se de Coccolithophorides.
In: GRASSE, P.P. (Ed.), Traite de Zoologie, 1, 439-470, Masson, Paris.
- - & FERT, C. (1954) : Observations surles Coccolithophorides actueles et fossiles
en microscope ordinaire et electrinique.
Ann. Paleont ., 40, 117-176, pis. 1-15.
GARTi\'ER, S. Jr. (1967): Calcareous nannofossils from Neogene of Trinidad, J a-

a

158

Shiro NISHIDA
Explanation of Plate 17
Electronmicrographs of carbon replica. Scale bar represents 5 microns.

Fig.

1.

Gephyrocapsa reticulata NISHIDA n. sp.
Distal view. Paratype. KC18R-51. Nobori formation. Nobori, Hane, Muroto City.
Fig. 2. Gephyrocapsa reticulata NISHIDA n. sp.
Distal view. Holotype. KC18R-l. Nobori formation. Nobori, Hane, Muroto City.
Fig. 3. Gephyrocapsa reticulata NISHIDA n. sp.
Proximal view. Paratype. KC18R-22. Nobori formation. Nobori, Hane, Muroto City.
Fig. 4. Umbilicosphaera cricota (GARTNER) CoHEN & REINHARDTDistal view. KC55R-9. Ananai formation. Higashitani, Tonohama, Yasuda-cho, Aki··gun, Kochi Pref.
Fig. 5. Umbilicosphaera cricota (GARTNER) COHEN & REINHARDTDistal view. KC43R-14. Nobori formation. Nishitani, Hane, Muroto City.
Fig. 6. Emiliania huxleyi (LoHMANN) HAY & MoHLER
Distal view. KC18R-2. Nobori formation. Nobori, Hane, Muroto City.
Fig. 7. Pontosphaera alboranensis BARTOLINIKC5R-71. Nobori formation. Oso, Hane, Muroto City.
Fig. 8. Pontosphaera alboranensis BARTOLINIKC40R-12. Nobori formation. Nishitani, Hane, Muroto City.
Fig. 9. Ellipsoplacolithus productus KAMPTNER
Distal view. KC12R-19. Nobori formation. Nobori, Hane, Muroto City.
Fig. 10. Ellipsoplacolithus productus KAMPTNER
Proximal view. KC43R-5. Nobori formation. Nishitani, Hane, Muroto City.
Fig. 11. Ellipsoplacolithus Productus KAMPTNER
Proximal view. KC12R-52. Nobori formation. Nobori, Hane, Muroto City.
Fig. 12. Coccolithus pelagicus (WALLICH) SCHILLER
Distal view. KC18R-3. Nobori formation. Nobori, Hane, Muroto City.
Fig. 13. Coccolith us pelagicus (W ALLICH) SCHILLER
Proximal view of the distal shield. KC54R-13. Ananai formation. Higashitani,
Tonohama, Yasuda-cho, Aki-gun, Kochi Pref.
Fig. 14. Coccolithus pelagicus (W ALLICH) ScHILLER
Proximal view. KC60R-29, Ananai formation. loki, Aki City.
Fig. 15. Coccolith us pelagicus (W ALLICH) ScHILLER
Distal view. KC54R-9. Ananai formation. Higashitani, Tonohama, Yasuda-cho,
Aki-gun, Kochi Pref.
Fig. 16. Discolithina sp. B
KC20R-44. Nobori formation. Nobori, Hane, Muroto City.
Fig. 17. Helicopontosphaera kamptneri HAY & MoHLER
Proximal view. KC15R-62. Nobori fo.rmation. Nobori, Hane, Muroto City.
Fig. 18. Helicopontosphaera kamptneri HAY & MoHLER•
Distal view. KC37R-12. Nobori formation. Nishitani, Hane, Muroto City.
Fig. 19. Coccosphere
Coccosphere of Gephyrocapsa reticulata NisHIDA.
KC55R-11. Ananai formation. Higashitani, Tonohama, Yasuda-cho, Aki-gun, Kochi
Pre f.
Fig. 20. Coccosphere
Coc:osphere of Gephyrocapsa reticulata NISHIDA.
KC25R-63. Nobori formation. Nobori, Hane, Muroto City.
Fig. 21. Coccosphere
KC32R-27. Nobori formation. Nobori, Hane, Muroto City.
Fig. 22. Coccosphere
Coccosphere of Gephyrocapsa reticulata NISHIDA.
KC59-29. Ananai formation. loki, Aki City.
Fig. 23. Coccosphere
Coccosphere of Gephyrocapsa reticulata NisHIDA.
KC55R-1. Ananai formation. Higashitani, Tonohama, Yasuda-cho, Aki-gun, Kochi
Pref.
Fig. 24. Coccosphere
Coccosphere of Gephyrocapsa reticulata NISHIDA.
.
KC30R-28. Nobori formation. Nobori, Hane, Muroto City.

NISHIDA:

Nannoplanktons from Tonohama

q

/__..
''
.;

1,.

.·~.

... ,

t

..

6

e~ - ~~
10

11 _ _...._

Plate 17

583.

Nannoplankton .from the Tonohama groupmaica, and Gulf of Mexico. Kansas Univ.
Paleont. Contr., pap. 29, 1-7, pls. 1-10.
GRAN, H.H. & BRAARUD, T. (1935):
A
quantitative 11~udy of the phytoplankton
in the B·ay of Fundy and the Gulf ofMaine. Biol. Board Canada, jour., 1,
279-467.
HAY, W.W., MoHLER, H. & WADE, M.E.
(1966) : Calcareous nannofossils from
Nal'chik (north-west Caucasus). Eclogae
geol. Helvetiae, 59, 379-399, pls. 1-13.
- - , - - , ROTH, P.H,, SCHMIDT, R.R. &BOUDREAUX, ].E. (1967) : Calcareous
nannoplankton zonation of the Cenozoicof the Gulf Coast and Caribbean Antillean
Area and transoceanic correlation. Trans.
Gulf Coast Assoc. Geol. Soc., 17, 428-459,
13 pls.
HoNJO, S. & OKADA, H. (1969) : Neogene
and Quaternary nannofossils from theBoso Peninsula, Chiba Pref. Atlas ofjapanese Fossils, No. 6-31, Tsukiji-shokan,
Tokyo. (in Japanese)
KAMPTNER, E. (1941) : Die Coccolithineen
der Siidwestkiiste von Istrien. Nat. Hist.
Mus. Wien, Ann., 51, 54-149, pls. 1-15.
- - (1952) : Das mikroskopische Studium
des Skelettes der Coccolithineen (Kalkfiagellaten). Mikroskopie, 1, 232-244 &
375-386.
- - (1963) : Coccolithineen-Skelettreste aus
Tiefse ablagerungen des Pazifischen Ozeans. Nat. Hist. Mus. Wien, Ann., 66,
139-204, 9 pls.
KATTO, J., NAKAMURA, J. & TAKAYANAGI,
Y. (1953): Stratigraphical and paleontological studies of the Tonohama group,
Kochi Prefecture, Japan. Kochi Univ.,
Res. Rept., 2-32, 1-15, pls. 1-2. (in Japanese)- - & OzAKI, H. (1955) : On the Miocene
Nobori formation, Kochi Prefecture.
Ibid., 4-1, 1-7. (in Japanese)- - (1960) : Report of geological investigation. in: Report of fundamental for the
Ashizuri-Muroto National Park. Muroto
Section. Kochi Prefectural Government,
1-20, pis. 1-20. (in Japanese)
KuRIHARA, K. (1968) : Notes on the Benthonic Foraminifera of the Tonohama Group,

159

Shikoku, Japan. Trans. Proc. Palaeont.
Soc. japan .. N.S., 70, 267-283, pl. 28.
LoHMANN, H. (1902): Die Coccolithophoridae,
eine Monographie der coccolithinenbildenden Flagella ten. Arch. Protistk., 1, 89165, pls. 4-6.
MAKIYAMA, J. (1927): Molluscan fauna of
the lower part of the Kakegawa series in
the province of T6t6mi, Japan. Mem.
Colt. Sci. Kyoto Imp. Univ., ser. B, 3-1,
art. 1, 1-147.
- - (1931): Stratigraphy of the Kakegawa
Pliocene in T6t6mi. Ibid., 7-1, 1-53, 2 pls.
MARTINI, E. & BRAMLETTE, M.N. (1963):
Calcareous nannoplankton from the experimental Mohole drilling. jour. Paleant., 37, 845-856, pis. 102-105.
- - & WoRSLEY, T. (1970): Standard Neogene calcareous nannoplankton zonation.
Nature, 225, 289-290.
MciNTYRE, A. & BE, A.W.H. (1967): Modern Coccolithophoridae of the Atlantic
Ocean-!. Placoliths and Cyrtoliths. DeepSea Res., 14, 561-597, pis. 1-12.
- - , - - & PREIKTAS, R. (1967): Coccoliths
and the Pliocene-Pleistocene boundary.
Progress in Oceanography, 4, 3-24.
MuRRAY, G. & BLACKMAN, V.H. (1898): On
the nature of the coccospheres andrhabdospheres. Philos. Trans. Roy. Soc.
London, 190B, 427-441, pis. 15-16.
NISHIDA, S. (1969): Nannofossils from Japan
I. Discoasters from Noto. Trans. Proc.
Palaeont. Soc. japan, N.S., 75, 136-152,
pls. 15-17.
NoMURA, S. (1937) : The molluscan faunafrom the Pliocene of Tosa. japan. jour.
Geol. Geogr., 14, 67-90, pl. 6.
0TSUKI, Y. (1905) : 1: 200,000 Geological map"Muroto Misaki" with a explanatory text.
Geol. Surv. Japan, Tokyo.
OTUKA, Y. (1932) : Cycle of sedimentationin the Japanese Neogene. Geogr. Rev.
japan, 8, 905-932. (in Japanese)
SAITO, T. (1963): Miocene planktonic Foraminifera from Honshu, Japan. Sci. Rept.
Tohoku Univ., ser. 2 (Geol.), 35, 123-209,
pls. 53-56.
SALES, E. (1967) : Associations de Nannofossiles Calcaires du Cretace et du Ter-

Shiro NISHIDA

160

tiaire d'Afrique Occidentale. Rev. Paleobotan. Palynol., 5, 291-314.
STRADNER, B. & PAPP, A. (1961): Tertiiire
Discoasteriden aus Osterreich und deren
stratigraphische Bedeutung. ]b. Geol.
B.A., Sonderband 7, 1-160, pis. 1-42.
SuzuKI, T. (1930) : 1: 75,000 Geological map"Muroto" with a explanatory text. Geol.
Surv. Japan, Tokyo.
TAKAYAMA, T. (1967) : First report onnannoplankton of the Upper Tertiary
and Quaternary of the Southern Kwanto
region, Japan. ]b. Geol. B.A., 110, 169198, 10 pis.
- - (1969) : Discoasters from the Lamont
Core V21-98. (Preliminary reports of thePhilippine Sea Core. Part 2). Bull. Natl.
Sci. Mus. Tokyo, 12, 431-450.
TAKAYANAGI, Y. & SAITO, T. (1962): Planktonic Foraminifera from the Nobori formation, Shikoku, Japan. Sci. Rept. Tohoku Univ., ser. 2 (Geol.), spec. vol. 5,
67-106, pis. 24-28.
TsucHI, R. (1961): On the late Neogene
sediments and molluscs in the Tokai
region, with notes on the geologic historyof the Pacific coast of southwest Japan.
japan. jour. Geol. Geogr., 32, 437-456.
Ucmo, T. (1967): Is the geologic age of theNobori formation, Shikoku, Japan, Miocene or Pliocene ? Trans. Proc. Palaeont.
Soc. japan, N.S., 67, 114-124.
-~~~·

---

~--~------~~

Explanation of Plate 18
Electronmicrographs of carbon replica.
Fig.

1.

Fig.

2.

Fig.

3.

Fig.

4.

Fig.

5.

Fig.

6.

Fig.

7.

Fig.

8.

Fig.

9.

Fig. 10.
Fig. 11.
Fig. 12.
Fig. 13.
Fig. 14.

Scale bar represents 5 microns.

Discoaster kugleri MARTINI & BRAMLETTE
KC8R-15. Nobori formation. Oso, Hane, Muroto City.
Discoaster dilatus HAY
KC20R-34. Nobori formation. Nobori, Hane, Muroto City.
Dis coaster pentaradiatus T Ai" SIN HoK
KC43R-35. Nobori formation. Nishitani, Hane, Muroto City.
Discoaster surculus MARTINI & BRAMLETTEKC32R-37. Nobori formation. Nobori, Hane, Muroto City.
Discoaster brouweri TAN SIN HoK rutellus GARTNER
KC20R-39. Nobori formation. Nobori, Hane, Muroto City.
Discoaster pentaradiatus TAN SIN HoK
KC23R-ll. Nobori formation. Nobori, Hane, Muroto City._
Discoaster brouweri TAN SIN HoK
KC25R-48. Nobori formation. Nobori, Hane, Muroto City.
Dis coaster brouweri TAN SIN HoK rutellus GARTNER
KC45R-36. Nobori formation. Nishitani, Hane, Muroto City.
Discoaster brouweri TAN SIN HoK
KC18R-52. Nobori formation. Nobori, Hane, Muroto City.
Discoaster stellulus GARTNER
KC20R-43. Nobori formation. Nobori, Hane, Muroto City.
Discoaster stellulus GARTNER
KC15R-63. Nobori formation. Nobori, Hane, Muroto City.
Discoaster tani BRAMLETTE & RIEDEL
KC1.5R-18. Nobori formation. Nobori, Hane, Muroto City.
Discoaster pentaradiatus TAN SIN HoK
KC25R-36. Nobori formation. Nobori, Hane, Muroto City.
Discoaster pentaradiatus TAN SIN HoK
KC12R-5.
Nobori formation. Nobori, Hane, Muroto City.

J

NISHIDA :Nannoplanktons from Tonohama

Plate 18

lOp

583.

Nannoplankton from the Tonohama group

W ALLICH, G.C. (1877) : Observations on the
coccosphere. Ann. Mag. Nat. Hist., ser.
4, 19, 342-348, pl. 17.
YoKOYAMA, M. (1926):
Tertiary shells from
Tosa. Imp. Univ. Tokyo, Fac. Sci., jour.,

Aki
Ananai
Hane
Higashitani
loki
Kakegawa
Kochi
MurotoNahari*1C

sec. 2, 1, 365-368, pl. 42.
- - (1929) : Pliocene shells from Tonohama,Tosa. Imp. Ceo!. Surv. japan, Rept., 104,
9-14, pis. 7-8.

Nishitanig§:t:lNobori
~
Oso
~
fifl
Ropponmatsu 1-\ ;;tq~
Shioyarg~
Takanabeif~jflilJ
Tonohama
J ~
To sa
±
t!i'.
Yasuda
S3

-!±"

:z;>;

~

I*J
:fN

}f[

:t:l-

W~*
)II
tif
~
~

m

m

!!<r1

p
~ ;fiJ*

Erratum
The following correction should be made on page 145, right side of Text-fig. 1:
for, 33°90'

161

read, 33°28'

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 83, pp. 162-165, September 20, 1971

584.

PECULIAR MARKINGS ON A SANDSTONE LAYER OF THE
HAGINO FORMATION, NAGANO PREFECTURE*
KOTORA HAT AI and HIROSHI NODA
Institute of Geology and Paleontology, Faculty of Science,
Tohoku University, Sendai, Japan~!!FfWU·.k!llf~~.P:B~:E_IIliDLI::O)!f;f~tJ:$]pff.lr.-::>v'"'C:~!llf91tl:7Jcr"J~l1l*JJ5!0) ±IJLJII1'8 Hr.

~i!-t7.>f.)(tfmO)~y:B. :/1v 1-;6-][~0)~y:B./IfJI!]ilU:~r.

ripple-like current structure '/J~
Balanoglossus, Cosmorhaphe ~O)'fiDii'dflr.{CJ.t:.Y!~]Iiffi'/J~~~~
nt:.. 1:.:tL-a::~tlL.t:.*fi!Jil:, ~!fWJ~r.~IZS!-t7.>'bO)'"C'tJ:<, l.§ije~.P:E:I!EtJH:& lutite O)~(fJI!)~'/J~~;!L., ~l.)(~r.J:7.>ie\.~~;fi:I~Ji:!&,O)rULO)li;P;6-iJ; Quick sand c L."LiifE!libL.t:.F>J,Hr., ripplelike current structure -a:::n%lt L., lutite tf~~O)M(~iJ~.:t:tL; 0) ~ITiil:'"C' ~!fmO)flijli'df~ji:(Trail-like) 0) '!:, 0) c tJ: "'t:. 1::. c -a::*5W6JiL., .:t:tL; O)J!!i:~jt, ~~lHf.:f:'O)~Jllti®.f~Hr. "?v'"'Cii"6trCt:..
· :tHI j:j: ;J' J}f. - !llf 133 $ i'tJ~;! L.,.;c-O)j]jJ:~r. Arenicola,

Abundant trail-like peculiar markingsof small size were found on the surface
of a rippled sandstone layer exposed
along the Dojiri stream below the bridge
at Hatsuhiki, Ogawa-mura, Kami-Minochi-gun, Nagano Prefecture. These peculiar markings show considerable resemblance with detached or broken partsof the castings of such marine annelids
as the living Arenicola and Balanoglossus (HATAI and Mn, 1955), the detachedor small broken piece of Cosmorhaphe(HANTZSCHEL, 1962, p. W189, fig. 118-3),
which is a trace fossil found in flysch
deposits, and also probably with trailsof other kinds of marine animals (HANTZSCHEL, 1962). The trail-like markings orones of similar morphology were notrecognized in stratigraphically lower orhigher horizons of the sandstone layersof the rather thick alternation of sandstone and siltstone beds. Thus it canbe said that the peculiar trail-like markings occupy only a particular horizon of
the Hagino Formation, are restricted toonly a small area of the sandstone layer,.
show variation in their shapes and small
size, and resemble in their morphology
two different things, e. g., casting andtrail of marine animals. Having such
peculiar characteristics they seem worthyof description and interpretation, andthis is the purpose of the present article.
The sandstone layer preserving thetrail-like markings as shown in the textfigure occupies the middle part of the
Hagino Formation and is situated in asandstone rich alternation of sandstoneand siltstone superposed upon a granulepebble conglomerate with marine molluscan remains. The latter facies lie
upon a mudstone rich alternation of mudstone and sandstone of the Senmi Formation. The sandstone layer in question exhibits current ripple-like structures with the trail-markings mostly* Received Sept. 13, 1970; read Sept. 13,
1970 at Tokyo.

162

584.
fA.ge
lw

2z
-IW
a.. u

w

z
u

Peculia?" ma1·kings of the Hagino foTmation

F ORM AT I 0 N

s

JOSH ITA FORMAT ION
I K ARl

FORMA T ION

ARAKURAYAM~ TA KA F UANDESITESv

Vx~
FORMATION

-:E

~G'~~
·- .... . ·- -- .... -- .

HAG I NO

FORMATIONSENMIFORMATIO N~-

L ITHIC CHARAC TERR EMARKSMASSIVE, DIRTY

Conchoce/e-

GRAY SILTSTONE

Lucinoma.

F INE, THIN ALTER- Trail- l ike mark. . NATION OF sst&s l t. ings..-.. ...
. . ....
... ....

~ = zz;':z;:;t"::if-·':'-:"Z!~~~!~~{~:11. ·-· . -.. -..

w
0

CO LUMNARSECT ION

163---- .. ·. ' .. '-··-·-····GRANULAR-PES- MizuhopectenBLE CONGLOMERA- Mercena ria .
Sand pipe
TE, SANDSTONE ·~-ALTERNAT ION OF:silts!. & sst.

NI SH I KYO FORMATIO N I'Text-fig . 1. Columnar section of the Hagino Formation s howing the stratigraphi·c
hori zon of the trai l-like markin g s, and, position of the Ha gino Formation in the sequenceof formations distributed in the area.

occupying the troughs. The sandstone
with the markings was collected by Mr.
Michio KATO of our Institute during his
field work in the summer of 1969, andto him we express our thanks.
Examination of the abundant trail-likemarkings gave the impression that all
were originally filled and covered with
mudstone or lutite, but later removedby either weathering or erosion or both
agencies so that at present onl y variously curved shallow to rather deep grooves
remain on the surface of the sandstonelayer. The sandstone is medium grained, of' mudd y aspect, with current-likeripple structure on the surface, apparently non-fossiliferous, and only 15-25
mm thick, the former being measured
at the troughs and the latter at the
crests of the ripp le-structures. Near the
top of this rather thin sandstone layer
is a discontinuous streak of lutite material megascopically the same as theunderlying muddy layer forming a partof the beds of a lternating sandstone(mudstone).
The trail-like markings are slightly torather strongly sigmoidal, some extending for a distance of about 30 mm in
ma x imum , some for only about 10 mm,
and others only a fe w m illimeters inlength, and range up to or a little morethan 5 mm in maximum width . The
majorit y of the trail-like markin gs are
represented as grooves about several
millimeters in depth. Some of the markings are continuous, others discontinuous, some endin g in pitlike depressions,others mere ly horse-shoe shaped , bow
shaped, pinched at extremlttes, andstretched and streaked-out, but in general all show some kind of curvature.
The markings are situated v ariously.
The majority are found to occupy thetroughs of the ripple-structures, someoccur on the backs, all of the justmentioned are typically trail-like inplain -view as shown in the text-figure.
On the other hand, the pit-like depressions occur where there is a break inthe slope of the ripples, whether on
back, in trough or on the front slope,and the size and depth of the grooves.
as well as shapes are various.

164

Kotara HATAI and Hiroshi NODA

Text-fig . 2. Pho togi·aph of the trail -li ke markin gs on the rippled
sandstone la yer of the Hagino Formation. (Natural size)

The ripples appear as current ripples,
having their backs dipping at about 1618 degrees and their front side (foreslope) with angles of from 30 to 40 degrees, the crest-to-crest length is about
70-80 mm. A lthou gh the genera l measurements can be made there is considerable variation in the angles of both!;Jack and front slopes as well as in theirwave-len gths. In la teral view, the sandstone layer exhibits the development ofdark streaks, generally discontinuous,
usually horizontal or parallel with thebedding of the underlying alternating
layers of sandstone and siltstone (mudstone), sometimes broadly concave, attimes lumpy, frequentl y flaring up wards
as if making a multi-thrust structure,and .some broad to narrowly con vex.
When the dark streaks are broadly

concave their terminal parts may appear
at the surface, one at th e foot of thesteep s ide of the ripple s tructure andthe other at the foot of the low-angled
backs in broad shallo w sync lin al form.
The foot of the steep s ide of the ripples
is genera ll y marked by a streak (s) of
the same kind of dark colored mudd ymaterial as mentioned a lr eady. The
trail-like markings are found mostly inthe troughs between the crests, on the
low-an gled back-slope and the pit-like
depressions where there is a break inthe slope of the ripples.
In some cases at the lower part of the
gentle slopes bordering the troughs andsteep s lope of the preceding ripple there
is developed a close assemblage of finemore or less continuous wrinkles arranged parallel to the troughs in gen-

584.

era!, and sometime at an angle. Althoughless distinct such wrinkles are also foundin some cases at the foot of the steep
slope and adjacent to the troughs, andin such case trail-like markings show
close assemblage. Wrinkling thoughobscure can also be recognized on thebacks of the ripples near to the crests.
The ripples are characteristic in resembling current-ripples, yet differing
therefrom in that the general trend of
the front or foreslope (steep sides slope)is varied, not parallel with one another,appearing as if linguloid in part, andsome are developed at right angles tothe adjacent one, some have a small
crest in a shallow but broad trough,·others a high crest as a normal currentripple, and in some cases it appears as
if the crest were nothing but that of asmall anticlinal structure because bothsides have nearly the same slope angle.
From the features described above.
the undermentioned interpretation may
be given. After deposition of dirty
sands there was deposited a laminae of
lutitic material over which dirty sands
were deposited rapidly. As the dirty
sands were over-saturated or saturated
with sea water they formed quick sand,.and this was subject to gravitational
movement resulting in flowage sand. By
this flowage which had strong traction.activity, the underlying laminae was, inpart, pushed forwards, churned, incorporated into the moving quick sand as
minute mud balls or particles, and folded-in the sand as detached laminae
taking the form reflected by the gliding

Hagino

'f*

lllf

165

Peculiar markings of the Hagino formation

Hatsuhiki

surface and non-uniform velocity of themoving sand, and various other kinds offorms. By being pushed forwards someof the laminae were forced to crumple,
or wrinkle, overlap the preceding one
and to take shapes according to theshape and velocity of the moving front
and were forced up on the backs of theripple structure in front. When themoving sand was slow wrinkles weredeveloped at the foot of the ripple-slope
in front. Since the flowage of the sandwas not of the same velocity due to thefriction of the underlying sediments andother reasons, the angle of the slope,and to the different load, the resulting
ripple-like structure differed from that
produced by water current, and wascharacterized by its irregular discontinuous shapes. After the variously
shaped discontinuous wrinkles of muddy
sediment consolidated the muddy parts
were removed by weathering and erosion, resulting in the preservation of
the trail-like structures sporadically distributed at random on the surface ofthe ripple-structure of flowage sand.

ReferencesW. (1962) : in R.C. MooRE,
Treatise on Invertebrate Paleontology,
Part W, Trace Fossils and Problematica .
Ceo!. Soc. Amer., and Univ. Kansas Press,
p. W177-W245.
HATAI, K. and M11, H. (1955): Markings on
a Tidal Flat in Uranouchi Bay, Shikoku.

HXNTZSC!lEL,

Rec. Oceanogr. Works, japan, New Ser.,vol. 2, no. 1, p. 1.62-166, 1 pl.

:fJJ

'31

Senmi

=f Ji!.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 83, pp. 166-1.78, pis. 19-21, September 20, 1971:

585.

ON SOME PATINOPECTEN FROM NORTH AMERICA*
KOICHIRO MASUDA

Department of Geology, Miyagi University of Education, Sendai, Japan

~t.*iif:WY:HlQ:J Patinapecten fc:. --:::>v'"C: *-:'f3'vtt)j]lj,
IT:{>::iJf,:Q:Jv,~?vp 0 Patinapecten·!C --:::>v'"C7ijfy'E L Patinapecten vcm;-9 0 {, Q:JV';J:3Jl1=. · ft:fi:J:l;.tc 13 ;tic f;J:1'FtE LJJ:v<:::. c :>2nf]
GiJ•vc LJ.: (MASUDA, 1963), .l(-Q:JI:~1. ;Jt.*i1914!Ji$'%J:illQ:J*fr1o31'-n' G ¥11'i!fc':: ht-: Patinapecten Q:J-9 ----::-c Q:Jffij;O;, 5r; l "C~Q:J Patinapecten fc)iJJ-9 0 {, Q:J;O• /,§;O,fJtf,fll:· j;) 0 Ull'i!f l
f::_o4-@1, :lt.;){(gqlfijl$iH?fll'i!fc'::ht:.: Patinapecten fC--:::>v'"C*"*~ilt-:f;'fi,R, .) ""~::J@lfij)¥a: DuRHAM (1950) ;O;~cll\x l t-: Patinapecten Q:J:=::fill, i"tJ:;bi?, P. bakeri, P. bakeri diazi .B J:: '(f. P. marquerensis v;J:, Patinapecten c fi:£: <}]IJ:>'Rff.ftQ) Amussiapecten fCilij~Q) {, Q:Jl:• ;b 0 ;: :_ c ;O~nfl G n' ~;::: tJ:-? t-:,'*- t:.:, '7 ~ y r Y:l·l·l 0) Montesano Formation iJ• G ADDICOTT (1966) il~¥1l'i5- l t-:
Patinapecten, n. sp. fi, fJ 7js:,f£Q:J v';bvp 0 Patinapecten fc;tt L- -c ~i'fn~tJ~n/jl t-: Mizuhapecten Q:JJ,Ji:filll: ;b 'J, ~ G fC MACNEIL (1967) ;6~, ;/] :1- ?l·i§r4!JwQ:Jffl.'f,*fri}!: c ,i[',;bhMI!J/rtn' G~c~ l t:.: Patinapecten (Mizuhapecten) skanunensis vi, Mizuhapecten c:·v';l:t.J: <Patinapecten .l(-Q:J{,Q:JL:·;b0 C. c;O;aflGiPfCt.J:-:>t:.:o
4-@IQ:J 7i!f)tfU: -:>"C, Patinapecten Q:JJ:ill~fi"J)J;{fj;O;, fiE*'*xG~o"Cv't.:J:: IJ kf-:>
Ut.vcn,t-:J:: -:>"Cv't-:c. en~ nflGn•vctJ:-:>t.:Q:Jl:, lliiAE:i'RQ:J~JJ! .:CQ:Jf\hQ:Jft::fin;, ~iAE*Q:JPatinapecten c;!t;:ff L- "Cv' 0 C. c Q:J~nmc --:::>v'"CQ:JVE*Q:Jll~mfulc~.tl:f.filq'Tt:hko <':: G IC,~?FiftltMJtllleli, J!:i:7-/ 7 iJ• G1'$l!J L..t:.: Mizuhapecten, Swiftapecten .l(Q:JffuiJ>:, ~t.*®rm
W~t.tf~IC 7J;(fi l "C v't-: C. c ;~Jq1J;F,:g <':: hf.:o fiE-::> "C, 7js:7i}f)'GQ:Jfi!;',li!H'J:, ~t.'i:3f-t~Jfu~IC.Bit 0
Wlf~ :=::>'R Q:J xJ .H::, '211lifJ~JJJi!lHTI IR Q:J m:~. [fJJ:I!lrm Q:J ~nR tJ: c Q:J _He lt ~ tJ: R[~ :>2t'!f ":> -c v, 0 ,Q:J~.UJr*!Ci.P G HANNA and HERTLEIN (1927) .B J::±ll)EESf-f,!~based upon Pecten caurinus GOULD, a·.
common Recent scallop of the eastern
North Pacific. Thenceforth, Patinopecten
has frequently been described from theRecent seas of North Pacific, Tertiary
and Quaternary formations in the West
Coast of North America, Japan, Sakhalin
and Kamchatka. In 1961 MACNEIL proposed the new subgenus Lituyapecten
based upon Patinopecten (Lituyapecten)
lituyaensis MACNEIL from the Late Miocene (?) or Early Pliocene of Alaska.
On the other hand, from a study of the,so-called Patinopecten of Japan the writer·(MASUDA, 1963) pointed out that everyspecies of the so-called Patinopecten-

Introduction

The genus Patinopecten is one of themost interesting among the Cenozoic
Pectinidae of North America, because it
is abundant in species and individuals,
is restricted in its distribution . to theeastern North Pacific Ocean, and showsa wide range of morphological characters. Also, it has a rather restricted
geologic range.
Patinopecten was established by DALL
in 1898 as a section of the genus Pecten* Received Sept. 22, 1970; read Sept. 13,
1970 at Tokyo.
166

585.

Patinopecten from North America-ranging from the Late Oligocene to
Recent in Japan differs from the true
Patinopecten of North America, and heproposed a new genus !Vfizuhopecten for
most of the species of the so-called
Patinopecten of Japan, based upon Pecten
yessoensis JAY, a common Recent scallop
in Northern Japan. Moreover, the writerpointed out that it is open to question
whether all speciea described under the_genus or subgenus Patinopecten or referred to Patinopecten on the West Coastof North America can be referred to thetrue Patinopecten or Lituyapecten.
The writer studied numerous specimens of Recent and fossil species ofPatinopecten from the West Coast of
North America in connection with the.above mentioned problems. The specimens studied are preserved in the Department of Geology, Stanford University, Department of Paleontology, University of California in Berkeley, California Academy of Sciences in San Francisco, Division of Mollusks, Smithsonian
Institution in Washington, D. C., U.S.
Geological Survey in Menlo Park andAmerican Museum of Natural History
in New York.
The results of examination of thosespecimens lead the writer to consider
that among the species of Patinopecten
in North America, Pecten (Patinopecten)
bakeri HANNA and HERTLEIN (1927),
Patinopecten bakeri diazi DURHAM (1950),
and Patinopecten marquerensis DURHAM(1950) can not be referred to the genus
Patinopecten. Therefore, these species
described from the Pliocene formations
in Baja California, Mexico are in need.of a new classification. Moreover, it
became evident that Patinopecten (l'vlizuhopecten) skonunensis MACNEIL (1967)-can not be referred to i\1izuhopecten;
but Patinopecten n. sp., illustrated by
ADDICOTT (1966), from the Montesano

167

Formation in Washington represents a
new species of Mizuhopecten.
In the present article the discussions
on classification, descriptions and remarks on the above mentioned species
are given and also general considerations
concerning the systematics and occurrences of the genus Patinopecten.

Acknowledgments
Acknowledgments are due to Prof. A.
Myra KEEN of the Department of Geology, Stanford University and Dr. Leo
G. HERTLEIN of the California Academyof Sciences, for their continuous encouragement, criticisms and for reading
the manuscript .
During the course of the present work
the writer also received support fromthe following persons to whom he takes
this opportunity to express his deep
gratitude: Prof. ]. Wyatt DURHAM of the
Department of Paleontology, Universityof California in Berkeley, Drs. David M.
HOPKINS and Warren 0. ADDICOTT of
the U. S. Geological Survey, Drs. Wen dellP. WoODRING, Harald A. REHDER andThomas R. WALLER of the Smithsonian
Institution and Dr. Norman D. NEWELL
of the American Museum of Natural
History. Mr. Kenji SAKAMOTO of the
U.S. Geological Survey in Menlo Parkhas prepared most of the photographic
work.
Thanks are due to the Department of
Geology, Stanford University, Department of Paleontology, University of California Berkeley, California Academy of
Sciences, U. S. Geological Survey in
Menlo Park, Smithsonian Institution andAmerican Museum of Natural History,
for their permission to study their collections.
Acknowledgments are also made to168

Koichiro MASUDA

the Ministry of Education of the Japanese Government, for its permission to
study abroad.

Notes on Patinopecten

DALL (1898, p. 695) gave the following
diagnosis of the section Patinopecten of
the genus Pecten: "Valves with small
ribs, fiat on the right valve and sometimes dichotomous ; smaller and morerounded on the left valve; concentric
sculpture inconspicuous ; radial striae. absent or obsolete; ears subequal; valvesnearly equilateral". Subsequently, many
species were described from the Tertiary
and Quaternary formations in the North
America, Japan, Sakhalin and Kamchatka. ARNOLD (1906) and GRANT and GALE
(1931) used Patinopecten as a subgenus
of genus Pecten. GRANT and GALE (1931,
p. 192) gave the following diagnosis forPatinopecten : " Shell large, thin, sometimes of a somewhat pearly texture,having a circular outline and very low
convexity, valves usually equal, although
at times one or the other may becomenearly fiat; radial sculpture consistingof distinct ribs without minor striation,
sometimes with microscopic cross-hat·ching, ribs of the right valve compara·tively broad and squarish, sometimes
with a medial sulcus, those of the left
valve narrow, often sharp, with intercalaries if the ribs of the right valve
are sulcated ; hinge line usually short,ears of almost equal length, byssal notch
deep in the older species, more shallow
in Recent species". However, they did
not state any morphological characteristics of the interior surface.
In 1950 DURHAM raised Patinopecten
to the generic ranking, as do most recent
authors, and described two species andone subspecies of Patinopecten from the

Pliocene formations in Baja California,
Mexico. Subsequently, MACNEIL (1961)
described several Tertiary pectinids.
from Alaska and other northern regions.
of the West Coast of North America
and he raised Patinopecten to genericrank as DuRHAM had done, and established Lituyapecten as a subgenus ofPatinopecten.
Later, the writer (MASUDA, 1963) discussed the so-called Patinopecten of Japan and pointed out that all species ofPatinopecten in Japan ranging from
Oligocene to Recent can not be referredto the true Patinopecten on the West
Coast of North America but should be·referred to the other genera including
some new genera. And he proposed a
new classification for the so-called
Patinopecten in Japan. A single Pliocene
species, Pecten tokunagai YOKOYAMA,
was made the type species of a new
genus Yabepecten and was grouped withthe true Patinopecten and Lituyapectenon the West Coast of North America ..
At that time, based upon the true Patinapecten in North America, he added thefollowing morphological features to thedescriptions by DALL (1898) and GRANT
and GALE (1931) : " Rather thick, conspicuous auricular crura along inner
margin of auricles with a conspicuous,.
rounded, oblong distal denticle at extremity of posterior part,· that at. anterior part extends ventrally and termi·
nates distally in an oblong, rather
obscure denticle in right valve; left
valve with distal denticle at each extremity of hinge more conspicuous thanthat of right valve". Lately MACNEIL(1967) used Mizuhopecten which was established by the writer (MASUDA, 1963,
p. 151) based upon Pecten yessoensis ]A Y,
a common Recent scallop in Northern
Japan, for many Japanese species formerly treated as Patinopecten, as a sub--585.

Patinopecten from North America

genus of Patinopecten.
Systematic Descriptions and Discussions
Family Pectinidae

169

are narrower or nearly equal to theirinterspaces on the right valve and distinct, oblong auricular crura which arequite distinct in the younger stage but
tend to become obscure with growth(Text-figs. 1-2).

Subfamily Pectininae
Genus Patinopecten DALL, 1898
Patinopecten DALL, 1898, p. 695.
Type-species (Original designation) :Pecten caurinus GOULD, 1850. Recent.
Puget Sound, Washington, U.S. A.
Geological and geographical distribution :-Late Middle Miocene to Recent.
Alaska to California.
Remarks :-Patinopecten can be distinguished from lv!izuhopecten (so-called
Patinopecten in japan) by its smaller
auricles of which the anterior auricleof the right valve has a deep byssal
notch, by the much smaller posteriorauricle in comparison to the anterior
one on the left valve; depressed rightvalve; rather squarish radial ribs whichmm

Patinopecten (Patinopecten) slwnunensis

MACNEIL, 1967
1967. Patino pecten (Mizuhopecten) skonunensis
MAcNEIL, U.S. Ceo!. Surv., Prof. Paper:55:3, p. 42, pl. 4, fig. 2, pl. 6, fig. 7.

1-Iolotype :- Univ. Calif. Los Angeles,
No. 39474.
Remarks:- This species was describedby MACNEIL based upon an incomplete
right valve. However. it has auricularcrura which are considered to be a very
important shell character of Patinopecten(MASUDA, 1963). This species can not bereferred to Mizuhopecten.
TyjJe locality :-Skonun Point, about 5
miles east of Masset on the north coast

mm

200

200

0

){

0
){

0

X

0

"

"

o caurinus

o caurinus

x yessoensis

50
HINGE lENGTH

X
X

x yessoensis

100 mmText-fig. 1. Graph showing the relationship between the height and hinge lengthof shell.

1
DEPTHIRIGHT V.l

20mm

Text-fig. 2. Graph showing the relationship between the height and depth of rightvalve.

170

Koichiro MASUDA

of Graham Island, Queen Charlotte Is;
lands, British Columbia, Canada. Skonun
Formation. Late Miocene (?) or Early
Pliocene.
Subfamily Fortipectininae
Genus Mizuhopecten MASUDA, 1963
ivfizuhopecten MASUDA, 1963, p. 151.
Type-species (Original designation) :Pecten yessoensis JAY, 1857. Recent,Northern Japan.
Geological and geographical distribution :-Late Oligocene to Recent. Japan
to West Coast of North America.
Mizuhopecten warreni MASUDA, n. sp.
Pl. 19, figs. 1-3, Pl. 21, fig. 3
1966. Patinopecten n. sp., ADDICOTT, jour.
Paleont., Vol. 40, no. 3, p. 644, pi, 76,
fig. 8.

Holotype:-U. S. Nat!. Mus., no. 646491.
Description :-Shell medium in size andthickness, smooth, compressed, orbicularin outline, equilateral except for auricles,
subequivalve; valves radiately ribbed
and forming an angle of about 110° at
apex.
Right valve with about 20 fl.attish,
round-topped radial ribs and fine concentric incremental lines ; radial ribs
rather low, rounded, broader than theirinterspaces, rarely bifurcate towards
ventral margin; auricles medium in size,
subequal, anterior one with wide andshallow byssal notch, a few faint, fineradial threads and fine concentric lines ;posterior one truncated behind forming
an obtuse angle and with concentriclines ; interior surface rather smooth but
slightly folded corresponding to external
sculpture. Left valve with low, rounded,fine radial ribs, fine intercalary threads,

fine concentric line; and rather obscurefine network; intercalary threads usuallyappear at middle of shell length and tend
to become somewhat distinct towards
ventral margin ; ra::lial ribs much narrower than their interspaces. Hingewith simple, fine cardinal crura but
without auricular crura.
Dimensions (in mm) :Valve
HeightLength
Depth

R*
100
100
10

R
90
10

R
R R-L L65
74 85
65 11085
5 12 14** 7

L

65
65
5

*-holotype, **-thickness

Rema;-ks :-This species is named inhonor of Dr. Warren 0. ADDICOTT of the
U.S. Geological Survey.
From the above mentioned morphological characteristics it is evident that
this species should be assigned to thegenus Mizuhopecten. It can be distinguishc:l from MizuhojJecten yessoensis(JAY) by it:; small size, lack of radial
threads on the auricles and the presenceof intercalary threads in the interspaces
between the radial ribs.
Type locality :-U.S. Geol. Surv., Loc.
No. M2978. West Fork of Wishkah
River, Grays Harbor County, Washington. Montesano Formation. Early Pliocene.
Associated fauna:- Yabepecten condoni(HERTLEIN).

Subfamily Amusiinae
Genus Leopecten MASUDA, n. gen.
Type-species:- Pecten (Patinopecten)
bakeri HANNA and HERTLEIN, 1927. Pliocene. Baja California, Mexico.
Geological and geographical distribution:- Early Pliocene to Late Pliocene.
Baja California, Mexico.
Diagnosis :-Shell large, gently inflat-

585.

Patinopecten from North Americaed, of medium thickness, longer thanhigh, equilateral, subequivalve, rightvalve a little more inflated than left
valve which is nearly fiat in younger
stage but tends to become inflated withgrowth; right valve with distinct, per·pendicular sided, flatly round·topped
radial ribs which are sculptured withsometimes faint, fine radial threads, fineintercalary threads and fine, rugose incremental lines; left valve with distinct
but low, narrow radial ribs usuallysculptured with a few faint, fine radial
threads, a few fine intercalary threads,
and raised, regularly spaced, rugose, fineincremental lines; auricles large; rightanterior auricle angulated at end, withvery wide and shallow byssal notch ;hinge with very simple, low, fine cardinal crura with fine provinculum andwide and shallow resilial pit ; auricularcrura well developed, terminating distally in a distinct oblong denticle at eachextremity ; interior surface with distinct
paired internal ribs at lower part.
Remarks :-The present new genus isnamed in honor of Dr. Leo G. HERTLEIN
of the California Academy of Sciences.
The present genus resembles Patinapecten externally but Patinopecten lacks
paired internal ribs and has a well developed byssal notch below the rightanterior auricle. Amussiopecten (SACCO,
1897, p. 55) is closely related to thepresent genus but it is distinguishable
from Leopecten by its radial ribs which
tend to become obsolete towards theventral and lateral margins, lack ofradial threads on the surface of theradial ribs and no intercalary threads
in the interspaces between the radialribs. The morphological characteristicsof these two genera are somewhat similar to each other in their younger stages
but the surface sculpture in the adultstage is quite different. That is to say,171

it seems that the general morphologic
characters in the younger stage ofAmussiopecten are retained in the adultstage in Leopecten. Therefore, it is inferred that Leopecten may have descended from Amussiopecten before the Early
Pliocene, but no intermediate form is
known between the two.
Flabellipecten (SACCO, 1897, p. 55) isdistinguishable from the present one by
its rather more inflated right valve,plano-convex left valve, rather small
auricles and more distinct and complicated cardinal crura.
Considered from the standpoint of theassociated fauna, it appears that Leo·pecten might have been a tropical or
subtropical inhabitant as was Amussio-

pecten.
This new genus includes the following species : Pecten (Patinopecten) bakeri
HANNA and HERTLEIN, 1927, Patinopectenbakeri diazi DURHAM, 1950 and Patinapecten marquerensis DURHAM, 1950.

Leopecten bakeri (HANNA
and HERTLEIN, 1927)
Pl. 20, figs. 1, 2
1927. Pecten (Patinopecten) bakeri HAI'NA andHERTLEi:-:, Proc. Calif. Acad. Sci., Ser.
4, Vol. 1.6, p. 153, pl. 5, fig. 1.
1931. Pecten (janira) stearnsii var. bakeri
HAI'NA and HERTLEiN, GRA!':T and
GALE (in part), Mem. San Diego Mus.
Nat. Hist., Vol. 1, p. 224 (not pl. 4, figs.
1a, 1b).
1950. Patinopecten bakeri (HANNA and HERTLEiN), DuRHAM, Mem. Geol. Soc. Amer.,
43, p. 66, pl. 12, fig. 1, pl. 13, fig. 7.

Holotype:-Calif. Acad. Sci., No. 1865.
Remarks :-As this species was firstdescribed by HANNA and HERTLEIN (1927)
based upon two left valves, the characteristics of its right valve were un-

172

Koichiro MASUDA

known. In 1931 GRANT and GALE included this species as a variety of Pecten(janira) stearnsii DALL. They believedthat Pecten (Pecten) bosei HANNA andHERTLEIN, described at the same timewith bakeri, should be considered to bea young form of P. bakeri.
According to the writer's examinationof type specimens the following features
must be added ; Shell large, longer thanhigh, equilateral, nearly equivalve butright valve a little more convex thanleft; surface with distinct radial ribs
and raised, regularly spaced, distinct
incremental lines; right valve with about
23 rather low, flat-topped, square sided
radial ribs which are broader than theirinterspaces and with a few faint, fineradial threads on their surface near
ventral margin ; radial threads on surface of radial ribs appear at about middle part of shell and tend to become
somewhat distinct towards ventral margin ; interspaces between radial ribs withan intercalary thread. appearing at about
middle part of disc and tending to become distinct towards ventral margin,
also with secondary intercalary threads
near ventral margin ; auricles rather
large, with a very shallow byssal notch
below anterior one, provided with rather
distinct concentric lines and rarely witha few faint, fine radial threads; interior
surface provided with paired internal
ribs that are distinct near ventral margin ; hinge with very low, simple, finecardinal crura, wide and shallow resilial
pit with very fine, flat, internal ridges
which diverge downward, and auricularcrura which terminate distally in a distinct. oblong denticle at each extremity.
This species was first described in thesubgenus Patinopecten and later raisedby DuRHAM (1950) to generic rank. Externally the present species somewhat
resembles Patinopecten, but that genus

lacks the paired internal ribs and has
rather small auricles with a deep byssal
notch below the right anterior auricle
and rather weak auricular crura: actually
it is quite distinct.
GRANT and GALE (1931) considered
Pecten (]anira) bosei HANNA and HERTLEIN (1927) to be a young form of P.
bal<eri as mentioned earlier, but P. bosei
differs from P. bakeri in the smaller inequivalved shell, more inflated rightvalve, plano-convex left valve which isa little inflated at a very young stage
but tends to become flat or concave withgrowth and then a little inflated downward, and sculptured with low radial ribs.
Dimensions (in mm) :Valve
HeightLength
Depth

L*
135
150
ca. 12

R-L
R-L
140
131
168
155
ca.27**
23**

R
94
99

L
133
147

*-holotype, **-thickness

Type locality:-" Cuesta Blanca " inArroyo de Arce, 15 miles north of
Loreto, Baja California, Mexico. San
Marcos Formation. Early Pliocene.
Distribution:- Baja California, Mexico.
Leopecten bakeri diazi (DURHAM, 1950)
Pl. 20, figs. 3, 4
1931. Pecten (]an£ra) stearns££ DALL, var.
bakeri HAi'>l\'A and HERTLEI!'\, GRA!'\T
and GALE (in part), Mem. San D£ego·
Soc. Nat. H£st., Vol. 1, p. 224, pl. 4,.
figs. 1a, lb.
1950. Patinopecten bakeri diazi DuRHA:vi, Mem.
Geol. Soc. Amer., 43, p. 66, pl. 12, figs.
2, .pl. 13, fig. 4.

Holotype :-Mus. Paleon.t. Univ-. Calif.
Berkeley, No. 15968.
Remarks:- This subspecies is characterized by its large, compressed, subequivalved shell which is longer than

585.

high, right valve with squarish, distinct
radial ribs with very faint, fine threads
on surface of radial ribs near ventral
and lateral margins, an intercalarythread between radial ribs in adult specimens, and raised, rugose, regularly
spaced incremental lines; somewhat angulated auricles with a wide, shallow
byssal notch below anterior auricle. It
is sculptured with fine concentric lines
and several faint, fine radial threads;
the left valve having somewhat square
sided radial ribs in younger stage, withthree fine radial threads, and an intercalary thread in interspaces between
radial ribs, crossed by raised, rugose,
regularly spaced, fine incremental lines;
simple cardinal crura ; shallow resilial
pit; and paired internal ribs and distinct
auricular crura which terminate distallyin an oblong denticle at each extremity.
Leopecten bakeri (HANNA and HERTLEIN) differs from the present subspecies
in having the right valve with many fineradial threads at lateral margins and theleft valve with perpendicular sided majorradial ribs, distinct radial threads on
surface of radial ribs and tertiary intercalary threads in interspaces between
radial ribs.
Dimensions (in mm) :R-L* R-L
Valve
137 132
Height154 160
Length23
Thickness 19

R-L
125
145
18

173

Patinopecten from North America

R-L
54
63
12

R
L
96 106105 120
14** 13***-holotype, **-depthType locality :-l\!lus. Paleont. Univ.
Calif. Berkeley, Loc. No. A3566. East
side of l\!lonserrate Island, Baja California, Mexico. Carmen Formation. Middle
Pliocene.
Distribution :-l\!lonserrate Island ; Salinas Bay, Carmen Island ; Oto Bay, Carmen Island ; Baja California, Mexico.

Leopecten marquerensis (DURHAM, 1950)
Pl. 21, figs. 1, 2
1950. Patinopecten marquerensis DuRHA:V!,
Mem. Geol. Soc. Amer., 43, p. 67, pl.
14, figs. 1, 2.

Holotpye:-Mus. Paleont. Univ. Calif_
Berkeley, No. 15475.
Remarl<s :-This species is characterized by its subequivalved shell. in which
the right valve is a little more inflated
than the left valve; with a very wideand shallow byssal notch below the rightanterior auricle; several fine radial
threads on the auricles of the left valve
but those of the right valve with only
concentric lines; radial ribs on rightvalve without radial threads on theirsurface.
This species differs from the otherspecies of Leopecten in having no radial
threads on the surface of the radial ribs
and in the interspaces between the radialribs of the right valve.
The external features of this species
somewhat resemble those of Pecten solarioides HEILPRIN (1887) from the Pliocene
Caloosahatchie Formation of Florida andalso those of Chlamys p!anicosta GARDNER (1943) from the Miocene Yorktown
Formation of North Carolina, but thosespecies from the Atlantic Coast differ
from the present one in having both
valves greatly inflated, more distinct
radial ribs, characteristic rugose incremental lines, larger auricles, very complicated cardinal crura, greatly projectedresilial pit, and deep notch under the
resilial pit.
Dimensions (in mm) : Valve
HeightLengthDepth

R-L* R
158 160
176 177
28** 1.5

R
150
175
17

R
136
140
11

L
152
174

* --holoty pe, **-thickness

L
126
140
10

174

Koichiro MASUDA

Type locality:-Mus. Paleont. Univ. Calif.
Berkeley, Loc. No. A3518. Marquer Bay,
Carmen Island, Baja California, Mexico.
Marquer Formation. Late Pliocene.
Distribution :-Baja California, Mexico.
Remarks on Patinopecten
from North America
In North America the following spe-cies or subspecies have hitherto been
described in the genus or subgenus
Patinopecten or referred to Patinopecten
by subsequent authors as indicated bya parenthesis.
1. Pecten (Patinopecten) propatulus
CONRAD, 1849 (DALL, 1898)
2. Pecten (Patinopecten) caurinus
GouLD, 1850 (DALL, 1898)
3. Pecten (Patinopecten) m.eekii
CONRAD, 1857 (DALL, 1898)
4. Perten (Patinopecten) coosensis
SHUMARD, 1858 (DALL, 1898)
5. Pecten (Patinopecten) expansus
DALL, 1898
6. Pecten (Patinopecten) dilleri
DALL, 1901 (ARNOLD, 1906)
7. Pecten (Patinopecten) oweni
ARNOLD, 1906
8. Pecten (Patino pecten) healeyi
ARNOLD, 1906

9. Pecten (Patinopecten) purisimaensis
ARNOLD, 1906
10. Pecten (Patinopecten) turneri
ARNOLD, 1906
11. Pecten (Patinopecten) weaveri
CLARK, 1915
12. Pecten (Patinopecten) rhytidus
DALL, 1921
13. Pecten (Patinopecten) oregonensis
HOWE, 1922 (SLODKEWITSCH, 1934)
14. Pecten (Patinopecten) kernensis
HERTLEIN, 1925
15. Pecten (Patinopecten) bakeri
HANNA and HERTLEIN, 1927
16. Pecten (Patinopecten) lohri
HERTLEIN, 1928
17. Pecten (Patinopecten) yalwtagensis
CLARK, 1932
18. Patinopecten bakeri diazi
DURHAM, 1950
19. Patinopecten marquerensis
DURHAM, 1950
20. Pecten (Patinopecten) haywardensis
LUTZ, 1951
21. Pecten (Patinopecten) haywardensis
calaverasensis HALL, 1958
22. Patinopecten (Lituyapecten)
poulcreekensis MACNEIL, 1961
23. Patinopecten (Lituyapecten)
lituyaensis MACNEIL, 1961
24. Patinopecten (Lituyapecten)
falorensis MACNEIL, 1961

Explanation of Plate 19(Natural size)
Mizuhopecten warreni MAsUDA, n. sp.

Fig. 1.

Right valve. Holotype, U.S. Nat!. Mus., No. 646491. Lac.: U.S. Geol. Surv., M2978.
West Fork of the Wishkah River, Grays Harbor County, Washington. Montesano
Formation. Early Pliocene.
Figs. 2a-b. a, Right valve. b, Left valve. Paratype, U.S. Nat!. Mus., No. 646492. Lac.: U.S.
Geol. Surv ., Loc. No. M2987. Same as above.
Fig. 3. Right valve. Paratype, U.S. Nat!. Mus., No. 646493. Lac.: U.S. Geol. Surv., Lac. No.
M3038. Same as above.

MASUDA :Patinopecten from North America

Plate 19

585.

Patinopecten from North America

25. Patinopecten, n. sp. ADDICOTT, 1966
26. Patinopecten (Mizuhopecten)
skonunensis MACNEIL, 1967
Among the species or subspecies listed
above, the names Pecten expansus DALL
and Pecten oweni ARNOLD are invalid
because these specific names were preoccupied. Therefore, Pecten expansus
DALL was renamed by ARNOLD as Pecten(Patinopecten) healeyi in 1906 and Pecten
oweni ARNOLD as Pecten (Patinopecten)
lohri by HERTLEIN (1928). Pecten rhytidus
DALL described from Alaska represents
a left valve of Fortipecten hallae (DALL)
as already pointed by MAcNEIL (1943).
Moreover, as stated above, it is evident
that Patinopecten bakeri, Patinopectenbakeri diazi and Patinopecten marquerensis can not be referred to the genus
Patinopecten. Patinopecten n. sp. (ADDICOTT, 1966) should be referred to thegenus Mizuhopecten, and Patinopecten
skonunensis can not be.
From the above mentioned it is to be
noted that the occurrence of the genus
Mizuhopecten from the Montesano Formation on the West Coast of North
America in association with Yabepecten
condoni (HERTLEIN) (MASUDA and ADDICOTT, 1970) is very significant for theinterpretation of paleozoogeography of
the Northern Pacific during the Late
Tertiary. The genus Yabepecten is
known from the Early Pliocene formations distributed in the Japan Sea
Borderland (MASUDA, 1962b) and considered to be a cool to cold water inhabitant. On the other hand, Mizuhopecten is known from Late Oligocene to
Recent in japan (MASUDA, 1963) andfrom paleontological data it is believedthat Mizuhopecten might have beenoriginally a warm water inhibitant in
Late Oligocene to Early Miocene time.
The changes in the marine environ-175

mental conditions from the Late Oligocene to Recent probably have greatly
influenced the biological conditions of
the marine fauna, but Mizuhopecten has
become adapted to different environmental conditions. Therefore, it is inferred that Mizuhopecten warreni branched off from the Mizuhopecten stock as aresult of its eastward migration fromthe East Asia to the West Coast of North
America followed by localization andadaptation in the Early Pliocene.
As a result of gradual changing ofenvironmental conditions from Tertiary
to Recent it is considered that only
Mizuhopecten yessoensis (JAY), which
may have acquired its stasigenesis(stability as a species) in the Early
Pliocene, could servive to the Recent
but the other species became extinct.
Similarly, the genus Patinopecten on theWest Coast of North America shouldhave been influenced by the changes ofthe marine environmental conditions
from the Late Miocene to Recent andonly Patinopecten caurinus (GOULD) which
first appeared in the Early Pliocene formations in the northern part of the West
Coast of North America survived to the
Recent but the other species became
extinct at the end of Tertiary. Thesechanges in the environmental conditions
from the Tertiary to Recent in the West
Coast of North America (DURHAM, 1950b)
coincide well with those in the JapaneseIslands (MASUDA, 1962b).
Therefore, the occurrences of theJapanese pectinid genera such as Yabepecten (MASUDA and ADDICOTT, 1970),
Fortipecten (MACNEIL, 1943), Swijtopecten(MASUDA, 1959) or Mizuhopecten in the
Pliocene formations of the northern partof the West Coast of North America
are very significant for circum-Pacificcorrelation of the Neogene formations
and for the interpretation of paleozoo-

176

Koichiro MASUDA

geography in the North Pacific.
From the Pliocene formations developed on the North Sakhalin and Kamchatka Peninsula, SLODKEWITSCH (1934,1938), ILYINA (1963) and KRISHTOFOV!CH(1964) described some species of Patinapecten, but judging from the descriptions
and the figures their species of Patinapecten almost all should be allocated to
the genus Mizuhapecten but some ofthem should be referred to the genus
Fartipecten. Therefore, it is evident thatthe true PatinajJecten does not occur in
Sakhalin or in Kamchatka or in theJapanese Islands.
The appearance of Leapecten in Early
Pliocene formations in Baja California
is very interesting and may be of considerable significance for the interpretation of the paleogeography of Central
America and North America. Because
Leapecten is known only from the Pliocene formations in the southern part of
the West Coast of North America andnot known from the Pliocene formationsin the East Coast of North America, it
can be inferred that the phylogenetic
changes from Amussiapecten to Leapecten
were related to the changes of oceanographic conditions. That is· to say, itis thought that the Pacific and Atlantic
Oceans must have been separated by theland bridge connecting North America
and South America at least in the very
Late Miocene to Early Pliocene (WOODRING, 1966). This is also supported by
the study of DURHAM (1961).
In 1942 HAAS reported the occurrenceof Patinapecten prapatulus (CONRAD) (?)
from the Middle Miocene formation in
Costa Rica, but such assignment is. veryquestionable, because Patinapecten is restricted in its distribution to the central
and northern part of the West Coastand its geological range is restricted to
the Late Miocene to Recent.
References
ADDICOTT, W.O. (1966): New Tertiary Marine Mollusks from Oregon and Washington. jour. Paleont., Vol. 40, no. 3, pp.
635-646, pis. 76-78.
CLARK, B.L. (1915): Fauna of the San Pablo
Group of Middle California. Univ. Calif.
Pub/., Bull. Dept. Geol. Sci., Vol. 8, no.
22, pp. 385-572, pis. 42-71.
- - (1932): Fauna of the Paul and Yakataga Formations (Upper Oligocene) ofSouthern Alaska. Bull. Geol. Soc. Amer.,Vol. 43, pp. 797-846, pis. 14-21, 1 text-fig.
DALL, W.H. (1898): Contributions to the
Tertiary Fauna of Florida, with especialreferences to the Silex Beds of Tampa
and the Pliocene Beds of the Caloosahat-

Explanation of Plate 20(All figures x 1/2)

Leopecten bakeri (HAi"NA and HERTLEIN). 1, Right valve. Topotype, Mus. Paleont.
Univ. Calif. Berkeley, No. 30053. 2, Left valve. Holotype, Calif. Acad. Sci., No.
1865. Lac.: Calif. Acad. Sci., Lac. No. 794. "Cuesta Blanca" in Arroyo de Arce,
15 miles north of Loreto, Baja California, Mexico. San Marcos Formation. Early
Pliocene.
Figs. 3, 4. Leopecten bakeri diazi (DURHA~'l). 3, Right valve. Paratype, Mus. Paleont. Univ.
Calif. Berkeley, No. 15969. 4, Left valve. Holotype, Mus. Paleont. Univ. Calif.
Berkeley, No. 15968. Loc.: Mus. Paleont. Univ. Calif. Berkeley, Loc. No. A3566.
East side of Monserrate Island, Baja California, Mexico. Carmen Formation.
Middle Pliocene.

Figs. 1, 2.

MASUDA:

Patinopecten from North America

Plate 20

585.

Patinopecten from No1·th America

chie River. Trans. Wagner Free Inst. Sci.
Philadelphia, Vol. 3, pt. 4, pp. 571-947,
pis. 26-37.
DuRHA:\1, W.J. (1950a): Megascopic Paleontology and Marine Stratigraphy, in ANDERSON, S.A.,_ DURHAM, W.J., SHEPARD,
F.P., NATLAND, M.L. and REVELLE, R.,
1940 E.W. Scrips Cruise to the Gulf ofCalifornia, Part II. Ceo[. Soc. Amer.
Mem., 43, pp. 1-216, pis. 1-48, text-figs.
1-3, 10 tables.
- - (1950b): Cenozoic Marine Climates of
the Pacific Coast. Bull. Ceol. Soc. Amer.,Vol. 61, pp. 1243-1264, 3 text-figs.
- - (1961): Paleogeographic Conclusions inLight of Biological Data. "Symposium,
Pacific Basin Biogeography". 1Oth PacificCongress, pp. 355-365, 4 text-figs.
GARDNER, J. (1943): Mollusca from the Miocene and Lower Pliocene of Virginia andNorth Carolina. Part 1, Pelecypod a. U.S.
Ceo[. Surv., Prof. Paper 199-A, pp. 1-178,
pis. 1-23, 2 text-figs., 2 tables.
GRANT, U.S. and GALE, H. (1931): Catalogueof the Marine Pliocene and Pleistocene
Mollusca of California. Mem. San Diego
Soc. Nat. Hist., Vol. 1, pp. 1-1036, pis.
1-32, 15 text-figs.
HAAS, 0. (1942) : Miocene Mollusca from
Costa Rica. jour. Paleont., Vol. 16, no.
3, pp. 307-316, 7 text-figs.
HALL, C.A., Jr. (1958): Geology and ?aleontology of the Pleasanton Area, Alameda
and Contra Costa Counties, California.
Univ. Calif. Pub!., Bull. Dept. Ceo!. Sci.,
Vol. 34, no. 1, pp. 1-90, pis. 1-12, 2 textfigs., 5 maps.
HANNA, G.D. and HERTLEIN, L.G. (1927):
Expedition of the California Academy of
Sciences in the Gulf of California in 1921:
Geology and Paleontology. Proc. Calif.
Acad. Sci., Ser. 4, Vol. 16, no. 6, pp.
137-157' 1 pl.
HEILPRIN, A. (1887) : The Miocene Molluscaof the State of New Jersey. Trans. Wagner Free Inst. Sci. Philadelphia, Vol. 1,
pp. 1-134, pis. 1-18.
HERTLEIN, L.G. (1925) : New Species of Marine Fossil Molluscs from Western North
America. Bull. Southern Calif. Acad. Sci.,

177

Vol. 24, pt. 2, pp. 39-46, pis. 3-4.
- - (1928): Pecten (Patinopecten) lohri, newname for Pecten oweni ARNOLD, a Pliocene species from California. Nautilus,
Vol. 41, no. 3, pp. 93-94.
HovvE, I-I. V. (1922) : Faunal and Stratigraphic
Relationship of the Empire Formation,
Coos Bay, Oregon. Univ. Calif. Pub!.,
Bull. Dept. Ceo[. Sci., Vol. 14, no. 3, pp.
85-114, pis. 7-12.
IL YI~A, A.P. (1963): Mollusks in the Neogene of Kamchatka. Soviet Petrol. Sci.
Res. Ceo!. Expl. Inst., 202, pp. 1-242, pis.
1-54.
KEEN, A.M. and BENTSON, H. (1944): Check
List of California Tertiary Marine Mollusca. Ceo!. Soc. Amer., Spec. Papers No.
56, pp. 1-280, 4 text-figs., 2 tables.
KRISIITOFOVICH, L.V. (1964): Mollusks in
the Tertiary Sediments of Sakhalin. Soviet Petrol. Sci. Res. Ceo!. Expl. Inst., 232,
pp. 1-343, pis. 1-55.
LUTZ, G.C. (1.951): The Sobrante Sandstone.
Univ. Calif. Pub!., Bull. Dept. Ceo!. Sci.,
Vol. 28, no. 1.3, pp. 367-406, pis. 15-18, 3
text-figs.
MAcNEIL, F.S. (1961): Lituyapecten (New
Sub:5enus of Patinopecten) from Alaska
and California. U.S. Ceol. Surv., Prof.
Paper 354-J, pp. 225-239, pis. 25-46.
- - (1967) : Cenozoic Pectinids of Alaska,
Iceland and Other Northern Regions.
Ibid., 553, pp. 1-57, pis. 1-25.
- - , MERTlE, ].B., Jr. and PrLsBRY, H.A.
(19,13): Marine invertebrate faunas of
the buried beaches near Nome, Alaska.
jour. Paleont., Vol. 17, no. 1, pp. 69-96,
pis. 10-1.6.
MASCDA, K. (1959) : On the Miocene Pectinidae from the Environs of Sendai; Part
14, On Pecten swiftii BERNARDI. Trans.
Proc. Palaeont. Soc. japan, N.S., No. 34,
pp. 86-96, 1 pl., 1 text-fig., 1 table.
- - (1962a): Tertiary Pectinidae of Japan.
Sci. Rep., Tohoku Univ., Ser. 2 (Ceo!.),Vol. 33, no. 2, pp. 117-238, pis. 18-27, 11
text-figs.
- - (1962b) : Notes on the Tertiary Pectinidae of Japan. Ibid., Spec. Vol., No. 5,
pp. 159-193, 9 text-figs., 9 tables.

178

Koichiro MASUDA- - (1963) : The so-called Patinopecten of
Japan. Trans. Proc. Palaeont. Soc. japan,
N.S., No. 52, pp. 145-153, pis. 22-23.
- - (1971): Amussiopecten from North America and northern South America. Ibid.,(in press).
- - and ADDICOTT, W.O. (1.970): On Pecten(Amusium) condoni HERTLEIN from theWest Coast of North America. Veliger,
Vol. 13, no. 2, pp. 153-156, 1 pl.
SLODKEWITSCH, B. (1934): Stratigraphy andFauna of the Tertiary Deposits of Western Coast of Kamchatka, Part 1. Trans.
Geol. Oil. Inst., Ser. A, fasc. 29, pp. 1202, pis. 1-18.
- - (1938) : Tertiary Pelecypods from theFar East. Pts. 1 & 2. U.S.S.R., Acad.
Sci., Palaeont. Inst., Palaeontology of

U.S.S.R., Vol. 10, pt. 3, fasc. 1.9, pp. 1275, pis. 1-106.
TucKER-ROWLAND, H.I. (1938): The Atlantic
and Gulf Coast Tertiary Pectinidae of theUnited States. Sec. III, Systematic Descriptions. Mem. Mus .. Royal d'Hist. Nat ..
Belgique, Ser. 2, fasc. 13, pp. 3-76, pis.
1-6.
WEAVER, C.E. (1942): Paleontology of the
Marine Tertiary Formations of Oregon
and Washington. Univ. Washington Publ.
Geol., Vol. 5, pts. 1-3, pp. 1-789, pis. 1104.
WooDRII\'G, W.P. (1966): The Panama landbridge as a sea barrier. Amer. Philos.
Soc. Proc., Vol. 110, pp. 425-433, 3 textfigs.

Explanation of Plate 21
Figs. 1, 2. Leopecten marquerensis (DURHAM). x 1;2. 1, Right valve. Holotype, Mus. Paleont..
Univ. Calif. Berkeley, No. 15475. 2, Left valve. Paratype, Mus. Paleont. Univ. Calif.
Berkeley, No. 15462. Loc.: Mus. Paleont. Univ. Calif. Berkeley, Loc. No. A3518.
Marquer Bay, Carmen Island, Baja California, Mexico. Marquer Formation. Late
Pliocene.
Fig. 3. Mizuhopecten warreni MAsUDA, n. sp. x 1. Right valve. Paratype, U.S. Nat!. Mus.,No. 646494. Loc.: U.S. Geol. Surv., Loc. No. M2978. West Fork of the WishkahtRiver, Grays Harbor County, Washington. Montesano Formation. Early Pliocene.

MASUDA:

Patinopecten from North America

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Transactions and Proceedings of the PalaeontologicalSociety of Japan

September 20, 1971

New Series No. 83

CONTENTS
TRANSACTIONS
582. KURIHARA, Kenji: Foraminifera from the Hayama Group, Miura Peninsula ........... . ... . . ...... . .. .... . ..... . ..... . . . . . ..... . . . ........... 131
583. NISHIDA, Shiro: Nannofossils from Japan IV. Calcareous nannoplankton
fossils from the T6nohama Group, Shikoku, Southwest Japan ...... . . 143
584. HAT AI, Kotara and NODA, Hiroshi: Peculiar markings on a sandstonelayer of the Hagino Formation, Nagano Prefecture

162585. MASUDA, K6ichir6 : On some Patinopecten from North America . . . . . . . . . . 166