a -!t" 1i- ± ij) ~ ~·.:k·!~fTransactions and Proceedingsof thePalaeontological Society of Japan
l'Jew Series

No. 55

Palaeontological Society of Japan
Sept. 20th, 1964

CONTENTS
TRANSACTIONS
Page

471.

Notes en Palmaean Leaf from the 6arai Flora !Upper Cretaceous). Oarai
machi. lbaraki Prefecture, Japan .. Toshiji 6YAMA and Hidekuni l\IATSUO 241

472. Some Molluscan Fossils from the Tertiary Muro Group in the Kii
Peninsula, Japan........................................ Hiro'o NATORJ 247

473. A Cretaceous Trigonid from the \·liocene l\lisaki Formation in the l\huraPeninsula, Kanagawa Prefecture .................... 'l."asumochi MATOBA 256

474. Discovery of a Fossil f'erotrochus in the Miil<e Coal-field, Kyushu. japan.................................... Hidetaka KLIWDA and Hideo URATA 263

475. A Find of Spongiomorphoids from the Cretaceous System of Rebun
Island and the Esashi Group of the Esashi t\lountains, Ilokkaido ....
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wataru l!ASHIMOTO and Sutekazu NAGAO 271

476.

Naticid Gastropods from the \liyazaki Group.

tPalaeontological Studyof the Miyazaki Group- X) .............................. Tsugio SHUTO 281
SHORT NOTE

12.

Discovery of Conodonts and Horothurian Sclcrites in japan........... .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Klaus ]. !\!tiLLER 294

President: Teiichi KOBA YASIII
Councillors:

Kiyoshi ASA!\O (Editor of '· Fcssils "), Riuji El\DO. Haruyoshi Fum.toTo,

Shoshiro HANZAWA. Tetsuro I-IA::\AJ (Secretary), Wataru HASHI!\IOTO (Treasurer).
Kotora HATAI, Ichiro HAYASAKA. Hiroshi OZAKI (Planning). Teiichi KOBAYASHI,
Tatsuro l'viATSU!\IOTO (Editor of Special Publications), l\iasao l\111'\ATO, Tokio
SHII<A!\IA (1\lembership). Fuyuji TAKA! (Editor). Ryuzo TORIYAMA
Assistant Secretary:

Takeo ICIIIKAW AAll Communications relating to this Journal should be addressed to the

PALAEONTOLOGICAL SOCIETY OF JAPAN
Geological Institute, Faculty of Science, Lniversity of Tokyo, Japan

Trans. Proc. Palaeont. Soc. Japan, N. S .. No. 55, pp. 2·11-246, Sept. 20. 1964

471.

NOTES ON PALMAEAN LEAF FROM THE OARAI FLORA(UPPER CRETACEOUS).
OARAI MACHI. IBARAKI PREFECTURE, JAPAN*
TOSHIJI OY Al'vlA
lbaraki t:ni\·ersity
andHIDEKUNI I\1ATSUO
Kanazawa University*V!:fi7i!J;Jll+ CJ:fmr'l~*"~) l~i~IIH Lt-: i' ::.- ftr.')~)1·;.:. "?~ · -c : ;: t0 i' :/fi!-O)~Jl'ft. 1963if•. ·I Jl · ~~f.l:~iR*~"J!:~~"?;tL -c. ~.IJA:7~¥*~~;&1i,ffillf.J~~t0~1:t..J"'(. :T-111!1:¥/i i;· L t-:
7-:~ti(i !ffr.l:flft0 fJHi\ ttfr~ Ji!"f: Lt-:Jiriw::.. it!£ (7)-A -r:: ~ 7.> :tiff! Mi11 t.i'·JJl.~O) iliiiii 1ft:.::. ¥fiJ! L t:. <b0)"1?~.;;,. :1-'ic~t.:~*c;;~ J.>fl:. ~~l!lb:ittr,!.!JmO);- :/frt!f;trt0=:f!rlt-~¥J1 L-n. 7.>(7)-r. we~O)ft:riB!l c .lt~llltt-1" Lt:..
*:l'llwtv1'i:O) Sabaliles nipponicus. S. taislmensis J: IJ ;b:k!J'IJ"t:. :lt*llb'ffllli:im S.
pou·elli. lrrlt <fi1f'ffli!!:i!¥. S. apalachicolensis K.1J..:l"C1.'7.>, ~ t7)~Jtt0i!P:Hilffl~~I.J:J:m:a~*·t:~ 7.>.:. c <b ~t\\r.r~7d'L "(, li!tillt.O) t 0) c K'illJ l. 1Jl(i!li:l11!41~ c '? -c Sabalites ooaraiensls
c'fflffl;-t'7.>, i':/'fJj-~)1 c l'"Ct. f\(i;:l'il[t7)~f.c:l?f~1lfi!!il.:.:ol.'t:';b;'&[llt0fil!l?~J.>. if,::,.
:k~Jtllfi~Y1lifO).r.ft(i~.I'!!1Jltl~~~i" 7.> t0<~ill~t.di\r!OC.litt0 -<)"( t j;,J.>,:J-:IIi~lX · ffi~~Hil
I. Introduction

species was yielded in Tsushima Islands,
1\'agasaki Prefecture, butS. E:\DO doubts
its being different from Sabalites nipponicus.
In the continental Eastern Asia. Sabalites chinensis was described by S. ENDO
from the Fu-shun coal·field in southern
Manchuria (North-Eastern Province ofChina). where the Palaeogene strata
occur. In the continent of America,
however, this genus has been known by
the upper Cretaceous forms. Thus. thegenus Sabalites is known to occur sinceCretaceous period in the Northern Hemishere.
6arai flora is considered by T. OYAMA,
that it grew in abundance in the late

Two species of the palmaean leaves
are hitherto known; one of them is
Sabalites nipponicus (Saba! uipponlca
KRYSHTOFOVICH, 1918) emended by S.
E:\DO. 19311; the other is Saballles
taishuensis established by K. TAKAHASHI
in 1958 as a new species.
The former species occurred in the
Eocene coal-fields of Takashima. Nagasaki Prefecture, Kyushu, of Bibai in
Hokkaido. and in the Oligocene coal·
fields in ?-Jorthern KyGshG. and Ube
City. Yamaguchi Prefecture. The latter• Received May 20. 1964: read Nov. 10.
1963.

2.!1

Toshiji 0 l";Lllil and Hidekuni MATSUO

2·12

Cretaceous age in japan. though theoccurrence of the genus Xilssonia of theprimitive Cycas common in the l'vlesozoic
flora is not recognized in this flora.
Consequently, there are two interpreta·
tions on the age of the Oarai flora : first,
if Sabalites has been found only in the
Palaeogene formation in Japan. the Oarai
flora may possibly have been considered
Palaeogene in age: secondary. if the
Oarai flora is of the upper Crct a ceo us
age. then. this Sabalites species must be
the oldest in Eastern Asia.
Nevertheless. T. 0YA:\IA recognized in
the Oarai flora 1he following Mesozoic
species. suggesting that it is of Lhe upper
Cretaceous age.
They are: Tlwllites
yabei (KRYSIITOFOVICH) llARI{IS, Coniopteris burejensis (ZALESSKY) SEWARD.
Zamites megaphyl/us (PHILLIPS) SEWARD,
0/ozamites sp .. etc.
llere, the writers wish to express theirsincere thanks to Dr. T. SArrO of thelbaraki University, and also to Dr. I.
I·IAYASAKA for his kind criticism andfor reading of the manuscripts.

II.

age, as they very closely resemble thoseof the l\linato shale of Awaji Island,
Kinki District, japan.
The 6arai formation is 1.300 m inthicl<ness, and consists of many conglomeratic layers intercalating threehorizons of the plant beds.
The columnar section along the coastof Nakaminato City by T. SAin\ 1958.
is shown in Fig. 1.

~"-s·.:-:; :.C:; .?"J:11ey~:: !:1

Ur.::-.:::!z • .:r:-.~:--r.":;':<:.'2.::-•••~~=-.:. ~.,:;,:?e1e~:'r~i:!.

?.;ra:::::::-'"':'!1.?'' ~ :fl!.

Geological Notes on the

Oarai Formation
This Oarai formation was establishedby 1-1. OZAKI and T. SAITO in 1955. and\vas believed to continuously lie under
the Nakaminato formation. which yieldedsome ammonites. It is evident, therefore. that with various plant fossils must
be of l\Iesozoic age. These l'vlesozoic
plant fossils were described by T.
·Qy AI";! A as the 6arai flora of tlw upper
Cretaceous age in the years 1956 to 1959.
Of the animal fossils. especially turreted
ammonites and an echinoid, T. SAITO
published notes in 1958 and 1959, and condueled that they are of upper Senonian

Fig. 1: The Columnar Section along theCoast of Naka-GawH (T. SAlT<), HlS8).

Ill.

Occurrence of the new species

This Sabalites ooaraiensis was discovered by S. ISIIIDA. a student of the
Kanazawa University from the upperof these plant-bearing beds. when ll.
iviATSUO and se\·cral students of Kanazawa University visited the locality of
the Oarai flora, guided by T. SAITO

471.

24:3

Palmaean J,eaf fl'o?n the Oarai Flm·a1n ApriL 1963. The materials collected
were all incomplete fragments, except
for this characteristic palmaean form
which shows the deltoid-form at thebase of the leaf. The slab of rock withthe fossil leaf was found up-side downon the fluvial deposits on the coast of
the Naka-gawa. However, it is certainthat the rock must have been derived
from the black sandy layer and medium
grey sandstone layer in alternation,
representative of the 6arai formation.

Gawa

0 c e a nq_;oam0cFig. 2:

IV.

1\lap showing principal locality of the C)arai Flora.

Description of the new speciesl\1onocotyledoneae
Pal mae

Saba/ites SAPORTA, 1865
Sabalites ooaraiensis new species
Fig. ·1.

Description :-Incompletely preserved
small palmae:~n leaf; flabcllate. Rachis
42 mm in u·idth, and up to 86 mm inlength on the surface; ligule large.

triangular, adherent to the upper sideof the rachis. Rayssl ightly carinate, 4,1
in numbers; midrib of rays slender;
lateral wins parallel to midrib. indistinctly.
Discussion :-Only a specimen is at disposal. but it shows the characteristic
deltoid rachis which closely resembles
previously known forms of Sabaliles.
The writers have measured dimentionsof other known species from japan,}.Janchuria and elsewhere: the result isgiven in the following table.

244

Toshiji OYAMA a.nd lhdekuni ilfATSUO
texture. The new species appears, how·ever, to have a very close resemblance
to Sabat major HEER (1855) in the Tertia·
ry of Switzerland. which was establishedby F. UNGER in 1841 as Flabellans major(UNGER, F., 1841: 42. XIV, fig. 2): never·theless, it differs from these specimens(BEER. 0. 1855: XXXV; XXXVI. fig. 2)
in its more numerous rays: it differsfrom the Kuma-form of the upper Eoceneof 5hikoku, Sabalites nipponicus (NAGAI.
K. 1957: II. fig. 2) in its fewer rays andlarger size: it differs from Bibai·formof the Oligcccne of Hokkaid6. S. nipj:onicus Ff\TO (KRYSIITOFOVICH, A. 1918:
XLI. fig. 1) in its wider rachis and more
numerous rays: it differs from Sabalites
laishue1Bis T AI\ AHA~ HI (1958: XX VIla)in its larger size.
Further, the present species is close!}'allied to Sabalites powe/li, described by
E. \V. BEHHY (1930: X. fig. 6 resembles
especially very closely the new species)
from the Wind River Basin of Green

Fig. 3: Relatior: between Lengthand Width in the Rachis.
L: Length; W: Width

The taxonomic relations of all these
species are not clear from what are
given in the table below. But this ne\Vspecies differs from the other in its
wider rachis. longer ligule, and thinner
Table 1:

The measurement of ruchis and rays in numbers of the palmaean leaL

I

I

I
I

Species Xame

Sabalites chinensis, E:-:oo

Oligocene

122 mm

S. nipponicus, Er-mo

Oligocene

22

S. laishuensis, TAK.\HASIIJ

Oligocene

26

S. nipponicus, NAGAI

Up. Eocene

22

Sabczl major, HEER

Tertiary

Saba/ major, RlcJD &Oligocene

CI!A:-:Dl.EJ~

Sabalites apalachicolensis.
BERRY

5. pou:el/i. BERRY
Sabalites ooaraiensis n. sp.

Ray

Rays inCompleteleaf (Esti·
mation)

27+

35-45

2.6

33+

35-40

2.1+

45+

45-50

2.8

55+

I L;W
- - -I- - -JWidth LengthAge

75 mm j 3. 4
58

--54+

--62

27

60

30

?

I

1

55-60
'

30+

30-40

14+

Numerous'---

Oligocene20-·10I?

Eocene?

I

Up. CreLaceousi 12
I

2.2

.

Numbers
of

I

40-60

?

186+

--2.0

H+

:
I

Nume1·ous I
I
45-50
l

.41 1.

Pal-rnaean Leaf from the dami FloraRiver Age. but differs fro:n the latterin being smaller in size, and from theI3embridge-form. Saba/ major (UNGER);REID & CHA!\DI.ER, 1926: IV. fig. 26\ inbeing larger in size and the rays being
numerous.
This new species represents the oldest
known occurrence of the genus Sabaliles,
being the upper Cretaceous of jap:ln and

Fig. 4:245

the Eastern Asia in general.
Occurrence :-Oarai flora (Upper Cretaceous).
Locality :-At the right bank of the
Naka-gawa 350m up from the Kaimon·kyo (bridge). Iwai-machi. Oarai .Machi.
Higashi-ibaraki Gun, lbaraki Prefecture,
Kant6 District, japan. :.Lat. 36 19'28" ~.
and Long. 140"35'27' E.)

Sabalites ooaraiensis n. sp.

Ilolotype; Reg. no. 14012.

Toshiji Ol'ilMA and Hidelwn·i MATSUO

24fi

Collection :-Holotype; Reg. No. 14012.
Repository :-Department of Geology.
College of Liberal Arts, Kanaza\va
University.
References
BERRY, E. ·w. (19H): The upper Cretaceousand Eocene Floras of South Carolina andGeorgia. U.S. Ceo!. Sun• .. Prof. Paper. i3-1.
pp. 5-72. pis. 2-14. pp. ~)9-163, pis. LS-29.
- - (1916) : The Physical Conditions andAge indicated by the Flora of the Alum
Bluff Formation. Ibid .. 98-E. pp. ·ll-53,
pls. 7-10.
(1930): A Flora of Green Ri\·cr Agein the 'Wind River Basin of 'Vyoming.
Ibid .. 156-B, pp. S5-79, pis. 6-15.
Er-.:r>C>, S. (1934) : The geological age of the
Fu-shun Group. South Manchuria. Proc.
Imp. Acad.. Vol. 10. No. 8, pp. 486-489.
- - (1953): ~otes on the Cainozoic Plantsof East Asia (1, 2). Kumamoto four. Sci ..
Ser. 11, No. 2. pp. 13-17, pis. 3-6.
- - (1955): leones of Fossil Plants fromJapanese Island. (in Japanese). Sangyotosho Co. pis. 1-51.
HEER, 0. (1855): Flora Tertiaria Helvetae.
Die Tertiare Flora der Schweiz. /Jd. I.
pp. 1-117. pis. 1-50.
KRYSIITOI'OVICII, A. (1918) : Occurrence of
the Plam, Saba/ 11ipponica n. sp. in the
Tertiary Rocks of Jlokkaido and Kyushu.
jour. Geol. Soc. Tokyo, Vol. 25, No. 303,
pp. 59-66, pl. 41.
NAGAI. K. (1957) : The Upper Eocene Floraof the Kuma Group. in Lhe Ishizuchi
Range. Shikoku. japan.
Mem. Rltime
U11ir• .. Sec. II (Sci.), Vol. 2. No . .-J. pp.
73-82, pis. 1-2.
OYA~L\, T. (1956) : An Inspection of Lhe

Awaji Island
Bibai
Fu·shunIwai.machi
Kaimon·kyo

i!R. 1m IN;
~

!!!

tJi'.
if!j

Jl!l
1ft
PI]'

r9 m

Oarai Flora of Upper Cretaceous Oarai
Formation in lbaraki Prefecture. Japan.
Bull. Fac. Lib. Arts. Ibaraki Unit•., Nat.
Sci., No. 6, pp. 53-n pis. 1-9.
- - (1961): On the Conclusion of the Oarai
Flora from the Oarai Formation in Oarai,lbaraki Prefecture. Japan. Ibid., No. 12,
pp. 61-101, pis. 1-9.
OzAKI. H. & T. SAIT<). (1955): The Cretaceous System along the Coast of Nakaminato City, lbaraki Prefecture. (Geology
of lbaraki Pref. pl. 3). Ibid .. No. 5. pp.
37-·19, wilh 1 plate.
REID. E. M. & M. E.]. CI!A:XDLER. (1962);
Catalogue of Cainozoic Plants in the
Department of Geology. Vol. I. The Bern·bridge Flora.
British 1lluseum (Nat.
Hist.), pp. 1-206. pis. 1-12.
SAITO, T .. (1958) : Notes on some Cretaceous
Fossils from the Nakaminato Formation,
Nakaminato City. lbaraki Prefecture.
japan. Part I. Bull. Fac. Lib. Arts. lbaraki
Uui11., Nat. Sci. ]1/o. 8. pp. 83-94, pis. l-5.
- - (W59): Op. cil. Part II. Ibid., No. 9,
pp. 7~)-85, pis. 1. 2.
TAKAII:\Slll. K., (1958): Sa/Jalites aus den"rakata Schichten von Tsushima. :::\ordkyushu. Tram. Proc. Palaeont. Soc. japan.
N. S.. No. 30, pp. 18.'i-188. pl. 27a.
U:-~GEH. F .. (1841) : Chloris protogea: Bcitrilgc zu,r Flora der Vorwelt. H[t. 1. (Rc·
positor~· in Kyoto University).
YArn:. II., (1944): Palaeogene Age of the
Ube Coal-Field Yamaguchi·Pref.
Proc.
Imp. Acad. Tokyo, Vol. 20. pp. 725-731.
YAMAS,\1<1. T., (1952): Discovery of Sabalites 11ippon.icus from the Karatsu Coalfield. Kyushu, japan. ,Uem. Fac. Engiu.,
Kyus/111 Unit· .. Vol. 1.'1. No. 1, pp. 65-70,
fig. 1.

Kuma
Naka·gawaTakashima
Tsushima Island

(A.

T.i

H!i JiiJ 11 I
ii¥i
Jih
.~
*f

Trans. Proc. Palaeont. Soc. Japan. N. S .. No. 55. pp. 247-255. pl. 36. Sept. 20. 1961

·172.

SOM~ MOLLUSCA~FOSSILS FROlVI THE TERTIARY
11URO GROUP IN THE Kll PENINSULA. JAPAN*
HIRO'O NATORI
Institute of Geology and Paleontology, Faculty of Science,
Tohoku UniYersity

m-:*'\' W;~fjfc7) ft. {tTI:~ffr$~ l~Hlf.c7)[Y7j+'iff.<flc7) ~=::~>tltfi'1tlf IJ .. t_,j)j;:JH L.t.:~lft.T:lc?)'tfrNi Solemya (Aclwrax) muroewns, n. sp., Prtar hatau. n. sp .. Prlar kolor. ...·
sp. ~.1L!~L. ~V.H:I~"li\1\i.:.-:>l·""C~f'!U.:,fi lbt N/ }:Pilar kotoi, n. sp.

In this paper, themolluscs from one of the two localities
are described.
Acknowledgements are due to Profes·
sor Kotora IIATAI of the Institute ofGeology and Paleontology. Faculty of
Science, Tohoku University. for his contiguous guidance and encouragement
during the course of the present study.
Thanks are also due to Dr. Shozo HAYASAKA of the same Institute. for his valuable suggestions on taxonomy and paleoconchology; IVIr. Hiroshi NODA of thesame Institute. for his kind informationon the Miocene molluscan fauna of Japan;
and Dr. Koichiro MASUDA of the Department of Geology, Faculty of Education,
Tohoku University. for his suggestions
on the conchology. The writer also
wishes to thank l'vlr. Jiro I\:(>TO. forkindly donating his collection of molluscan fossils from the 1\luro Group to the\\Titer for study.

Introduction and Acknowledgements

The southern part of the Kii Peninsulaof Wakayama Prefecture. is occupied by
the so-called Shimanto Terrain. which
consists of the undifferentiated Mesozoic(?) I-litakagawa Croup and the Tertiary
Muro. Kumano and Tanabe Groups.
The l'vluro (;roup is characterized by
the vcrv thick flysch type deposits composed o.f sandstone, shale and an alternation of sandstone and shale. Theserocks are distributed in a mozaic patternwhich reflects the intensive disturbancebv folding and faulting. The group isaimost barren of fossils except for a few
problematica, and some molluscs \e. g.,
I-IARATA. TOKUOKA and MATSll\IOTO.
19631, which suggest the Oligocene tolower Miocene age.
From two localities in the ~luro GroupJiro KoTO of the Ishiwara Sangyo Com·pany was successful in collecting a few
molluscan fossils of rather good preservation although without the original shellmaterial. These molluscs are all ne\v toscience and consist of So/emya (Acharax)
muroensis. n. sp., Pilar lzataii, n. sp. andNotes on the Stratigraphy.
Paleontology andCorrelation

According to OHW AKI (1962), the socalled Shimanto Terrain in the central* Received June 10. 1964; read June 7. 1961
at Kyolo.

247

'248

Hiro'o 1\lATURI

part of the South Kii Peninsula can beclassified by the Nakaheji fault into twoparts which are known as the Hitakagawa Group on the north and the !\luroGroup on the south of the thrust fault.
The Hitakagawa Group nearly corre·
sponds with the lower group of the unknown t-,.1esozoic strata described by
SuZUKI (1939) and the 1\luro Group isalso equivalent to the upper group. The
Hitakagawa Group is correlated withthe lower part of the ~lesozoic Shimanto·
gawa Group (KATTO. KOJL\IA, SUYARI
and SAWAl\IURA. 1951) distributed in the~1uroto Peninsula. Kochi Prefecture in
Shikoku based upon the close resem·
blance in their lithology. geological struc·ture and occurrence of identical problem·
atical fossils.
According to IIARATA. el a/. (1963) the
Muro Group can be subdivided into threeparts based upon the lithological features.
These are named the Otonashigawa-r..luro.
Yomurakawa-Muro and Ukekawa-l\luroFormations in ascending order. The Oto·
nashigawa·Muro Formation. which iscomposed of flysch type alternations ofsandstone and shale with interbedded
medium grained sandstone and someacidic tuff beds. is conformably super·pose:l by the Yomurakawa-Muro Forma·tion of medium grained sandstone andflysch type alternation of sandstone andshale. The Yomurakawn-Muro Formation
is overlain with unconformity by the
Ukekawa-Muro Formation which is com·posed of conglomerate and flysch typealternations of sandstone and shale.
From the middle part of the Ukeka\vaMuro Formation a few molluscan species
have been reported by II ARATA, et a I.
(1963) ; These are Venericardia (Cycfo·
cardia) tokunagai YoKOY AI\! A, Costa cal·/isla cfr. shikokuensis KATTO, Porllandia(Portlandella) sp., and Acila (!leila) elon-gala NAGAO et IIUZIOKA.
Among these species, Venericardia(Cyclocardia) tokunagai was describedby YOKOYA:\IA 11924, p. 18, pl. 3, figs.
10-12) originally from the Asagai Formation of the joban coal-field. Fuku·
shima Prefecture. and has been recorded
from the Tanagura Formation of Fukushima Prefecture. the Nenokami Sand·stone of the Chichibu Basin, Saitama
Prefecture, the Onishibetsu Formation of
Hokkaido and the Togari formation of
Gifu Prefecture, all of which may belong
to the Oligocene to lower Miocene. Costa·
callista slzikokuensis was originally de·scribed by KA TTO (1960, p. 109. pl. 1,
fig. 4) from the ~lisaki Formation iUpper
Oligocene) of Shikoku. Acila (Aci/aJ
elongata was first described by 1\AGAO
et liUZIOKA (19:11, p. 113, pl. 31. figs. 14) from the Kawabnta Formation of Hok·kaido, and has also been found from the
1\lomijiyama Formation of Hokkaido.
With regard to the geological age of the
1\lomijiyama and Kawabata Formations.
different views have been expressed(listed by KAN~O and OGAWA. 1963).
The views presented place the forma·tions in an age ranging between lower
Oligocene to lower Ivliocene.
The new species to be described inthis article are Solemya (Acharax) muro·ensis. Pitor halaii and Pilar koloi, andwere collected from the rather upper
part of the Ukekawa-l\luro Formation of
the classiflcation worked out by HARA TA(HAI~ATA, el a/., 1963).
l'vlorphologically, the present new spe·
cies as an assemblage resemble, in many
features, the Oligocene to Miocene species of japan and the Oligocene speciesof Washington, Northwest America.
However, valves of both P. hataii and
P. kotoi are very thick, and in this respect differ from the other species of472.

Mollusccm Fossils from the Mnro Gtoup

the genus Pilar.
By the data at hand, it is thoughtthat the geological age of the present
new species may be Oligocene or lessprobably lower Miocene.

Description

Family Solemyidae
Genus So/emya LA:\fARCK, 1818
Subgenus Acharax DALL, 1908
Solemya (:lcharax) muroensis
NATOR!, n.

sp.

Pl. 36. fig. I.

One right valve was examined. Shell
small. subrectangular and compressed.
Beak weak. inconspicuous. situated welltoward posterior end.
Antero-dorsal
margin elongated. straight and parallelwith straight ventral margin; posterodorsa1 margin short, slightly convex andexcavated near the beak. Posterior end
acutely rounded; anterior end unknown.
Surface with numerous radiating,broad, fiat-topped. weakly incised ribs;
ribs stronger on middle surface of shell,

249

weaker and obscure on anterior and posterior ends; ribs broader on posterior
than on anterior part of shell ; interspaces of radiating ribs sculptured witha pair of two radiating lines extending
from near beak to ventral margin;
interspaces between two radiating lines
narrow. Concentric lines of growthstrong and irregular.
Dimensions:- Holotype (IGPS coli. cat.
no. 85727) ; length about 22.0 mm .. heightabout 10.5 mm., thickness about 2.3 mm.
(right valve).
Remarb :-The genus So/emya has
been recorded from the Jurassic System
to the Recent deposits of Japan. From
the Tertiary rocks of Japan the following species have been described.
Solemya n. sp .. KATTO. KoJl:l.lA, SUYARI and
SA WAM IJH A. 1961. pl. 4, fig. 17 (no description). Naharigawa Formation (Eocene) of the Shimanto Terrain, Kochi
Pref eel u re.
Solemya (ilcharax) bosoana HATAI and KoiKE.
1957. p. 86. pl. 4. fig. 1, Okuzure Conglomerate (Oligocene). Chiba Prefecture.
Solemya (Acliarax) dalli CLARK. 1925. p. i3.
pl. 22, fig. 3, Upper Oligocene of \Vash·
ington, Northwest America; Ushikubi·
toge Formation (Aquitanian) of the
Chichibu Basin, Saitama Prefecture.
Solemya (Ac/iarax) lokmzagai YoKoYA:O.tA;
So/emya lokwzagai YoKOYA:I.lA. 1925, p.
31. pl. 6. figs. 1-6. Miocene and Pliocene
deposits of the joban coal-field, Fukushima Prefecture: l\'lochiki and Tofutsu
Beds (lower Pliocene) of South Saghalien; Kunnui Formation (lVIiocene) of
Hokkaido: Poronai Formation (Oligocene)of IIokkaido; Oiwake Formation (lower
Pliocene) of Hokkaido; Kadonosawa Formation (Miocene) of Iwatc Prefecture;~itla
Formation (lower Pliocene) of~iigata Prefecture: Teradomari Formation (Miocene) of Niigata Prefecture:
Hiranita Formation (Burdigalian) of the
Chichihu Basin: Itahana Formation (Mio-!lil'O'O NATORJ

250cene) of Gunma Prefecture: Itsukaichi
Formation (Miocene) of Tokyo-to: Amatsu Group (Miocene) and Nishihata For·mation (Pliocene) of Chiba Prefecture:
Ennichi Formation (Miocene) of South
Korea.
Solemya (Ac!zara.r) gigas KAN:>."O, 1960. p.
187, pl. 50, ligs. 1-2, Iliranita Formation(Burdigalian).
Solemya tokzmagai e/ongata AoKr. 195•1. p.
:w, pl. l. fig. 15. Miocene deposits of thejoban coal-licld.
Solemya yessoensis KA:-o;EttARA. 1937, p. 155,
pl. 15. fig. 12, Oiwake Formation (lower
Pliocene).
Sofemya labeosa YoKoYAMA. 1928, p. 361. pl.
68, fig. 11. Kaigasawa Formation (Pliocene) of Kiigara Prefecture.

As compared with the above-mentioned
species, the present new species resembles Solemya (Acharax) da/li CLARK. but
differs form the latter by its curved
postero-dorsal margin and small shell.
Solemya n. sp. figured by KATTO el a!.
(1961) differs from the present new spe·
cies in having the antero·dorsal margin
extending obliquely with the ventral
margin and by the larger shell.
Locality:- ~lotomiya. i\lotomiya-cho,Higashimuro-gun. Wakayama Prefecture.
Ukekawa-l\luro Formation of the 1\luroGroup.
Geologic age:- Oligocene or lower
Miocene.

Family Veneridae
Subfamily Pitarinae
Genus l'itar Rd;~.IEI~. 1857

Pitar hataii NATOIH. n. sp.
Pl. 36, figs. 3a-b.

One right valve was examined. Shellof medium size, strongly inflated andelongate ovate.
Beak small. high,strongly curved inward and forward.
situated from anterior end at a distanceof about one-fourth the length of shell.
Antero-dorsal margin rather c<>nvex.
very strongly excavated near beak andvery steeply inclined downward andrunning into back ; postero-dorsal margin
nearly straight and passing into arounded posterior encl. Anterior end
narrowly but well rounded and passing
into a broadly arcuate ventral margin.
Lunule and escutcheon obscure.
Surface with numerous. rather roughand fine concentric, and irregularly
spaced lines of growth.
Dimensions :-1-iolotype nGPS coil. cat.
no. 85728); length about 43 mm., heightabout 33 mm.. thickness abouL 15 mm.
(right valve)
Remarks :-From the Tertiary rocksof Japan the following species of Pilar
have been described.
0YA~1A et Mtzm.:o. 1958.
p. 603. pl. 4. ligs. 1-6, Wakkanabe Formation (Eocene) of the lshikari Group,
Hokkaido; Shitakara Formation (Eocene)of the lshikari Group.
Pilar (')
Sllllllo.wwaensis (Yot<nYA~IA):
Vemts (?) sa1mosawaensis YoKOYA~IA.
1932, p. 239. pl. 3. fig. 5. Upper Shiroki
Formation of the Uryu Group (Eocene).
Hokkaido.
Pilar takashimaensis (NAGAo): Pi/aria taka·shimaensis NAGAO, 1928. p. 72. pl. 11. figs.
lla-b. Okinoshima Formation (LutetianPriabonian) of the Takashima coal-field,
Nagasaki Prefecture: Kawamagari For·mation (Eocene) of the Asakura coalfield, Fukuoka Prefecture: Meinohama
Sandstone (Aquitanian) of the Fukuoka
coal-lield, Fukuoka Prefecture.
Pilar kyushuensis (NAGAO): Pitaria kyuslmensis NAGAO, 1928. p. 70, pl. 12, figs. 1-10,
Sakasegawa Group (Lutetian) of the
Amakusa coal-field. Kumamoto Prefec-

Pilar soraclriensis

472.

Molluscan Vossils from the Muro Groupture: Okinoshima Formation; lojima For·mation (Lattorfian) of the Takashimacoal-fteld ·. Kawamagari Formation; Kiriyama Formation (Lutetian-Lattorfian)of the Isahaya coal-fteld, Nagasaki Prefecture: Funatsu Sandstone (Lattorfian)of the Takashima coal-field; Nango andTakigahirayama Formations (ChattianAquitanian) of the Nichinan Subgroup.
Miyazaki Prefecture.
Pilar yokoyamai (NAGAO): Pit aria yokoyanwi
NAGAO. 1928, p. 7-!. pl. 11. figs. 10-11.
Kakinoura Formation (Oligocene) ofNagasaki Prefecture: Nagayo Formation(Lattorfian) of the Isahaya coal-field.
Pilar matsumotoi (NAGAO): Pi/aria matsumotoi NAGAo. 1928, p. 73. pl. 11. !lg. 13.
pl. 13. ftgs. ·l-6. Ashiya Group (Aquitanian) of the Chikuho coal-field. Fukuoka Prefecture: iVIeinohama Sandstone:
Yamaguchi Formation (Aquitanian) of
the Isahaya coal-field: Tokuman Member of the Nishisonogi Formation (Aquitanian) of the Sakito coal-field. Nagasaki
Prefecture: Karatsu Formation (Aquitanian) of the Kitamatsu-Karat.;u coalfield. Nagasaki and Saga Prefecture~:
Takigahirayama Formation (Aquitanian)of the Nichinan Subgroup: Asagai forrr.ation (Oligocene) of the joban coalfield. Fukushima Prefecture.
Pilar ashiyaensis (NAGAO): Pitaria aslziyaensis \',\GAO, 1928. p. 72. pl. 9. fig. 12. pl.
13. figs. 1-:3. Yamaga Formation of the
Ashiya Group (Aquitanian).
Pilar (?) aflottmbonala (XA(;Ao): Pitaria (?)
alloumbonata NAGAO. 1928. p. 75. pl. 11.
figs. 14-15. 19. Kishima Formation (Aquitanian) of Saga Prefecture.
Pilar (Costellipitar) concentrica KAN:\0, 1958.
p. 177. pl. 2. ftgs. 8-9. Kamiyokoze Formation (Aquitanian-Burdigalian) of the
Chichibu Basin. Saitama Prefecture.
Pilar itoi (MAKJYA:-.r,\): Pi/aria itoi MAKJ·Y A:-.JA, 1926. p. 157. pl. 13. fig. 7. 1\Iankodo
Formation (Miocene) of Korea: Kase
Formation (middle Miocene) of the Kitamatsu-Karatsu coal-field.
Pilar okada11a (YOKOYA\IA); Venus olladana251

YOKOY.·\MA, 1932. p. 240. pl. 11, ftgs. 8-9.
Okada, Nomura and Poroshin Formations(Miocene) of the Uryu coal-field. 1-Iokkaido.
Pilar ,vabei 01TKA, 1934. p. 617. pl. -18, figs.
49-50, Kadonosawa Formation (Miocene)of lwate Prefecture.
Pilar hokkaidoensis No\IURA. 1935. p. 35, pl.
·l, ftgs. 1-2. Takikawa Formation (Pliocene) of Hokkaido: Togeahita Formation(Miocene) of Ilokkaido.
Pilar sendaica No\tl'RA, 1938. p. 258. pl. 35.
figs. 1-3. lOa -b. Tatsunokuchi Formation(Pliocene) of l\1iyagi Prefecture: Some
Pliocene deposits of the Paciftc side ofjapan.
P1tar sendaica monstrosa No~!URA. 1938. p.
259. pl. 35, figs. Sa-b. 9a-b, Tatsunokuchi
Formation (Pliocene).

As compared with the above-mentioned
species. the present new species resembles Pilar (Coslellipitar) concentrica KA-:\·NO in the outline. but differs from thelatter by the thicker valve. smaller beak.
stronger convexity and excavated anterodorsal margin, and also by the surface
ornamentations of the shell. Pilar kvushuensis (I'\AGAO) is another species allied
to the present one but is distinguishedfrom the present one by its more broadly rounded anterior and posterior ends.
more regularly ventral margin. and higher
and thinner valve. In the thickness ofthe valve. the present new species isrelatively thicker than the ones abovementioned.
The present specimen seems to havebeen slightly deformed by subsequentagencies, therefore its characteristic features are judged to be the straight posterodorsal margin. very strong convexity andcurved antero-dorsal margin. and very
thick valve.
J\·1ASUDA (1963) discussed on the relationships between the fossil specimens.
with shell materials and those without

Hiro'o 1VATORI

252

them in Dosinia (f'hacosoma) japonica(REEVE). and pointed out that on the
inner mold specimen the postcro·dorsal
margin carves much less th:tn in specimens with the shell material and theanterior part is more concave toward
the antcro-dorsal margin because of therelatively thicker shell materials thanthe other parts of the shell. Similarfeatures can be observed in the present
specimen.
Locality: -l'v1otomiya, !vlotomiya-cho.
Higashimuro-gun. \Vakayama Prefecture,
Ukekawa-Muro Formation of the !\luroGroup.
Geologic age: - Oligocene or lower
J\liocene.
J>itar kotoi N A TORI, n. sp.
Pl. 36. fig;;. 4a- b.

One left imperfeclly preserved valve
was examined. Shell large. strongly
inflated and elongate ovate. Beak verylarge. high, cun·ed inward and forward.
Antero-dorsal margin slightly concave,
excavated and gently sloping backward;
postero-dorsal margin unknown. Anteri·or end narro\vly rounded, passing into a
broadly arcuate ventral margin: posterior
end unknown. Lunule and escutcheon
unknown.
Surface ornamented with numerous,
rough concentric. irregularly spaced linesof growth ; concentric lines sometimes
distinct and more or less elevated so as
to become narrow concentric lamellae.
Dimensions :-Holotype (IGPS coli. cat.
no. 85729): length unmeasurable, heightabout 58 mm.. thickness about 15 mm.
(left valve).
Remarks:- The present new species
differs from Pi tar hataii, n. sp. in having
a larger beak, and concave. regularly
excavated and gently sloping backward

antero-dorsal m:trgin, while the latterhas smaller beak, convex, very strongly
excavated and very steeply sloping
backward antero-dorsal margin. weaker
growth lines and smaller size. Pilar
kyushuensis (NAGAO) is distinguishedfrom the present new species by its
smaller beak, rather broadly rounded
anterior end. regularly convex ventral
margin and rather thin valve. The
present new species. in outline andsurface orn:1111entation of the shell, re·sembles Pilar (Lame!liconcl!a) clarki(DICKERSO::\) figured by TEGLAND (1929.
p. 279, pl. 22. figs. 2-3} from the Eocene
deposits of Cowlitz River, Washington,
Northwest America, but differs by its
larger beak, narrower anterior end andthicker valve. In the thickness of thevalve. this new species is relatively
thicker than the above-mentioned speciesof Pitar except for Pilar hataii. n. sp.
Locality:- l'vlotomiya, l'vlotomiya-cho,lligashimuro-gun. Wakayama Prefecture,
Ukebwa-l\luro Formation of the Muro
Group.
Geologic age: - Oligocene or lower
1vliocene.

References
AoK 1, S .. (1954) : Mollusca from the Miocene
Kabeya Formation. joban Coal-field,
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472.

Molluscan

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8-22
IIAI!ATA, T .. ToKt;oi<A, T. and MATSt;MoTo,E., (1963): Some Important New Factsfrom the Muro Group in the South partof the Kii Peninsula-the New Occur.
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- - and - - (1953b) : Molluscan Fauna of
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1 text.fig.
1-llllAYAMA, K.. (1955): The Asagai Forma·tion and Its Molluscan Fossils in the
Northern Region. Joban CoaJ.fiel<i, Fuku·
shima Prefecture. Japan. Tokyo Kyoiku
Daigaku. Sci. Rep., Sec. C. Vol. ·1. Nos.
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K-v.. tAOA, Y., (1962): Tertiary Marine Mol·lusca from the Joban Coal.field, Japan.
Palaeont. Soc. japan. Spec. Papers, _\io.
8. p. 1 181. pis. 1-·21, text.figs. 1-3. tabs.
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--and 1-IAYAS.\KA, S .. (1959): 1~emarks
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KANEHARA. K.. (1937): On Some Tertiar~·
Fossil Shells from Hokkaido (Yes;;o).
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KA:-.::o-;o, S .. (1958) : New Tertiary Molluscs

the Mnro Group

253

from the Chichibu Basin, Saitama Pre·
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55. p. 157-229. pis. 1-7.
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KATTo. J .. (1960): Some ::\-lolluscan Fossils
and Problematica from the Shimanto
Terrain of Shikoku. Japan. Kochi Unit'··Res. Rep .. Vol. 10. No. 6, p. 107-115. pis.
1-2.
- - . KoJI:I.IA, J,. SuYAHI, K. and S,\\\'AML'RA,
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sources Map Sheet. Kochi Prefecture( 1/200.000).
- . - . - - and - - (1961): Explanat·
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MAKIYAMA, ].. (1926): Tertiary fossils fromthe North Kankyo.do. Korea. ](yolo Imp.
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1\.fJzt:;-;o, A .. (1962a) : Paleogene and Lower
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25-llliro'o 1VATOR!

- - (1962b): Paleogene and Lower Neogene
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the Correlation and Biochronologic Division of the Paleogene Strata in the Vicinity of Nishisonogi Peninsula, Northwestern Kyushu).
Ibid., Vol. 68, lllo.
807, p. 687-693. 2 text-figs., 3 tabs. (inJapanese with English abstract).
- - (1963): Paleogene and Lower :\eogene
Biochronology of the West japan (IlL
Stratigraphic and Geographic Distributions of Molluscan Faunas in Westjapan). Ibid., Vol. 69, No. 808, p. 3850, 2 text-figs .. 6 tabs. (in .Japanese withEnglish abstract).
..\IIJRAYA~IA, M., (1954):
Geological Map
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:\:\GAO. T., (1928) : Paleogene Fossils of theIsland of Kyushu. Japan. Tohoku Imp.
Unit• .. Sci. Rt'p., Ser. 2, Vol. 12. No. 1.

p. 1-140, pis. a, 1-17, 1 tab.
- - and HuzJoK,\, K., (19-11): Fossil Acila
from Hokkaido and Karahuto. /lokkaido
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No.2, p. 113-141. 3 pis
Nor>A. H .. (1962) : The Geology and Paleontology of the Environs of !vlatsunoyama, Niigata Prefecture, with Reference to the So-called Black Shale. Tohoku
Unit• .. Sci. Rep., Ser. 2, Vol. 34. So. 3,
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:l\o:-.ttmA. S., (1935) : A Note on Some Fossil
Mollusca from thu Takilwwa Beds of theNortheastern Part of Hokkaido, Japan .
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11olluscan Fossils from theTatunokuti Shell Bed exposed at Goroku
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Ibid., Vol. 19, No.2, p. 235-275, pis. 33-36.
OTUK,\, Y., (193·1) : Tertiary structure of
the Northwestern end of the Kitakami

Explanation of Plate 36(All figures in natural size unless otherwise stated)

Solemya (.-lchara.t') muroensis NATORI, n. sp.
Right ,-alve, Ilolotype. IGPS, coli. cat. no. 85727. Loc. lvlotomiya. l\lotomiya-cho, Higashimuro-gun, \Vakayama Prefecture. Ukekawa-Ivluro Formation of the Muro Group.
Fig. 2. Solemya (Acharax) dalli CLARK x0.7
Left valve, Holotype figured by WEAVER (1958. p. 20, pl. 5, fig. 5). S. U. 5238. Loc. One
and one-half miles of Twin Rivers. Clallam County, Washington, Northwest America.
Sandy shale of the upper Oligocene.
Figs. 3a-b. Pitar hataii NATORI. n. sp.
IIolotype. JGPS. coli. cat. no. 85728. 3a; Right \'al\•e. 3b; Apical view of fig. 3a. Loc.
~lotomiya, ;'vlotomiya-cho, Jligashimuro-gun, \Vakayama Prefecture. Ukekawa-Muro formation of the l\Iuro Group.
Figs. 4a-b. Pitar kotoi NATORI, n. sp.
Holotype. IGPS, coiL cat. no. 85729, ·Ia: Left vah·e. 4b: Apical view of fig. 4a. Loc. Sameas above.
Figs. 5a-c. Pilar I(I'USI/IIellsis (NAGAo)
Hololype described by NAGAO (1928. p. 70) as Pi/aria kyuslme11sis. IGPS. coil. cat. no.
36238. 5a: Left \'alve. 5b: Right vah·e. 5c; Apical view. Loc. West coast of Okinoshima. Kagasaki Prefecture. Okinoshima Formation (Lutetian-Priabonian).
Figs. 6a-b. Pilar clarki (DtcKERsor-.:)Topotype figured by TEGLA!\D (1929) as Pit Mia (Lamelliconcha) clarki DICKERSON. U. C.
No. 31543. 6a: Left valve. 6b: Anterior view of fig. 6a. Loc. Lower Cowlitz Valley,
southwestern Washington, North America. Upper Eocene Cowlitz Formation.
Fig. LNATORI:

Mollusca from Muro Group

Plate 36

4b

KuMAGAI

photo.

472.

Mountainland, Iwate Prefecture. Japan.
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Thesis (l\IS.).
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:\1otomiya
Muro
Nakaheji

255.Molluscan Fossils from the J.1Inro Groupj(t;*lfl Jl1 ll'A·~

cl!\\:

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- - (1933) : The fauna of the type Blackley,
Upper Oligocene of \Vashington. Ibid ..
Vol. 23, No. 3. p. 81-17·1. pls. 2-15.
'I:VATA~AnE. K., ARAI, ]. and HAYASHI, T.,(1950): Tertiary Geology of the Chichi·
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Geol., T-o!. 5, Pt. I, p. 1-:n!: Pt. 2, p.
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from the lowest part of the Jo-ban coalfield. Tokyo Imp. UniLJ .. four. Colt. Sci ..
Vol -15, Art. 3. p. 1-22. pis. 1-5.
- - (1925) : Molluscan remains from theuppermost part of the Jo-ban coal-field.
Ibid., Vol. 45, Art. 5. p. 1-3-!, 6 pis.
- - (1928) : Neogene shells from the oilfield of Higashiyarna, Echigo.
Tokyo
Imp. Unit•., four. Fac. Sci .. Sec. 2. Vol. 2,
Pt. 7. p. 351-362. pis. 68-69, 1 tab.
(1932) : Tertiary lVlollusca from the
Coal-tield of Uryu. Ishikari. Ibid., Vol.
3, Pt. 6, p. 221-2-!7. 4 pis.

Otonashigawa
Ukekawa
Yomurakawa

1'i 1~ }II
:11'1

HI

pt1 H Jll

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 55, pp. 256-262, pl. 37. Sept. 20, 1964

473.

A CRETACEOUS TRIGONID FROl\I THE l\HOCENEMISAKI FORMATION IN THE MIURA PENINSULA.
KANAGA W A PREFECTURE*
YASUMOCHI l'viATOBA
Institute of Geology and Paleontology. Tohoku University::::.l!li~I',~!;CI)rf 1 ~Ul==:~ll'l.l: 'J JWHI Lt-::~illi*e:::.:ffJJ.'l.: 3illl~f'-.»!Jm~. ~~~~~JII~i!.:::=.nrrrfic_:NtJ
PtfCI)3~~11!*-c:::-:.ft.rF,'M·t.>lf'~ill:fi:::O .!:;il<i::.3frJRfi::En·:tlfJ~~ht-:: (iif:JI'=~· 1952). :.
h~llit:MLt-::t'i;f,, Pterotrigonia {ttl::.~ L. ~t!ili~l!!UcCI) P. hokkaidoana ;::.~'iltl::.)!t{l.:l:"tQl(:.CI)""Ct,M~tdJiJ•..,t-:.,.::.;tL~;iL!ill'(L =l7.:H:1ict5Ml!LL

I¥J jj} I~~

the Institute of Geology and Paleont·ology, Tohoku University. for the oppor·
tunity to study the interesting specimen
and for his kind instruction throughout
this work. Acknowledgements are due
to Dr. Iliroshi OzAKI of the Natural
Science l'vluseum in Tokyo for his kindsuggestions and deep interest concern·
ing the occurrence of the trigonid shelL

Introduction
It is well know·n that trigonids wereabundant and had wide distribution
during the tvlcsozoic Era. especially theJurassic and Cretaceous.
However,during the Cenozoic Era only a few
descendants have been found in Aust·ralia and they range from Tertiary toRecent.
In l952, a trigonid fossil was collectedby tvlr. Jiro Usm with other l\liocene
fossils from a single locality and hori·zon of the l\lisaki Formation. at thesouthernmost part of the J\·Iiura Penin·
sula, during his geological work in thepeninsula. The writer had an oppor·
tunity to study this specimen under the
instruction of Prof. Kotora HATAI. The
aim of this work is to determine
whether the specimen can be considered
to be a Miocene species or whether itshould be interpreted as derived froman unexposed formation of Cretaceousage.
The writer here expresses his sincere
thanks to Professor Kotora !lATA! of

Occurrence
The specimen was collected by CS{jffrom a calcareous sandstone bed situ·
ated at the east side of the Misaki
harbour. l\1isaki-cho, Miura City, Kanagawa Prefecture (Fig. 1). According toUsm (1952), ...... at the boundary be·
tween the upper and low·er parts of the
Misaki Formation, at about 200 meters
east of the inlet of the 1Iisaki harbour.
there are intercalated calcareous sandstone beds. The calcareous beds are
considered to correspond to the lime·stone beds near .\Iisaki which have beenstudied by YOSHIWAI~A (1902). At theoutcrops east of the Misaki harbour,
calcareous conglomeratic sandstone al·
ternates with medium to fine grained* J{eceived June 10, 19&1; read June 7, 1964
at Kyoto.

25G

473.

Tt~igom'cl ft·om

Fig. 1. Locality of Pterotrigonia
cf. hokkaidoana (YEH.-\RA).

tuffaceous sandstone and mudstone. andhas yielded abundant molluscan shells.
From one of these outcrops alread:ymentioned a molluscan fossil belonging
to the genus Trigonia was collected ....
Its stratigraphic position is the uppermost part of the Lower ~\lisaki Formation ......
The occurrence of a well preserved
isolated Yalve of a trigonid from thecompact. yello,vish colored, fossiliferous
sandstone of the Neogene age, situatedon the eastern side of the l'vlisaki harbour is of interest. According to Prof.
K. HATAI of the Institute of Geology
and Paleontology. Tohoku University.
who sponsored ]. Usm·s graduation
thesis in the field and laboratory. themolluscan shell was found from a sandstone containing abundant remains ofsmall Ostrea, fragments of balanids andother pelecypods. The small oysters

the Misaki Formation257

are well preserved and some even retain
their original coloration, whereas thefragments of balanids and other pelecypods were more or less with faded
original coloration. some even showing
evidence of wear due to aqueous agencies. The trigonid shell. however. israther well preserved. showing its external sculpture in detail and the interiorfeatures could be observed after cleani:lg with a hand-drill. Howe,·er. thesandstone adhering to the trigonid shellis different from that in which it was
found.
From the same bed. UsuJ collected
other fossils as Chlamys miurensis·yOKOYAl'viA. Chlamys n. sp., Dentalium
yokoyamai :'viAKIYAMA. Balanus rostraIus HOEK, Odontlzocyatlws-like corals,
Bryozoa etc .. and concluded its geologic
age to be l'vliddle or Lower Miocene
upon the evidence of the fossils andalso from the stratigraphic consideration.
From where the trigonid shell cameand how it was embedded in the 1\eogene sandstone is problematical. It
could have been drifted with othermaterials by rafting ana deposited after
the raft was destroyed by rattening,
possibly it could have been washed out
by disintegration of an erratic which
may ha,-e been fossiliferous, because of
the small size and thick shell of thetrigonid it is evident that its resistanceagainst foreign agencies would be
strengthened. and it seems that there
may be other agencies which could
have brought the trigonid shell to itssite of deposition. Whatever the answer
be. it is evident that the trigonid shell
was collected from a fossiliferous sandstone of Neogene age. and the true explanation for the occurrence must be
reserved.

258

Yasumochi M.4TOBA
Paleontological andGeological Notes

Because of the importance in stratigraphy and abundant occurrences a;;well as large variety of forms, studies
on the trigonids have begun early in thehistory of the molluscs, and many
workers have attempted to classify thegenus Trigonia into finer divisions.
AGASSIZ in 1841 divided the genus into
eight sections, namely, Scaphoidae, Clavellatae, Quadratae, Scabrae. Undulatae,
Costatae. Glabrae and Pectinatae. This·classification was adopted with somemodification and additions by subsequ·ent workers. LYCETT (1872-79\ investigated in detail the Jurassic and Cretaceous trigonicls of England and classified them into eight sections. added the
new section Byssiferae to those previously recognized by AGASSIZ except
Pectinatae. STOLICZKA (1871) divided
the genus into six groups in his study·of Indian trigonids. Several authors. on
the other hand, subdivided Trigonia s.
lat. generically. After BAYLE's Miophore!la (1878) and COSS:\IAN's Eotrigonia.and _Yeotrigonia (1912) were proposed.
modern workers Iike VA:-J HOEI'E); (1929).
CIHCKi\IAY (1932), Cox (1952) and others
erected new genera and subgenera. In
Cox's scheme of classification the Trigo·
niidae are restricted to Trigonia s. lat.
and classified into 23 genera and 11
subgenera. Recently KoBAYASHI (1954)
and others studied the Mesozoic trigonids
of Japan and adjacent countries andproposed a systematic classification of
the trigonids.
The specimen of Scabrae-type trigonid
treated in this article, having wingshaped. very inequilateral outline andopithogyrous umbo. obviously belongs to
the subfamily Pterotrigoniinae. Thissubfamily is in a position far from thesubfamily Neotrigoniinne KoBA YASII!
t1954). the known post·Cretaceous trigonids. which consists only of two genera,~Veotrigonia and Eotrigonia.
The subfamily Pterotrigoniinae was proposed by
VAN HOEPEN (1929) and it included six
genera. Recently KOBAYASHI and NAKA.t-;0 (1957) re-examined the subfamily
and classified it into three genera andone subgenus, namely genus Petrotrigo·
nia VAN HoEPE~. subgenus Rinetrigonia
VAN HoEI'EN. genus Scarbrolrigonia
DIETRICH and genus .tlcantholrigonia
VAN HoEPEN. The present specimen
differs from .-lcanthotrigonia and Scabrotrigonia in the arrangement of costellaeon the area. It is asigned to Pterotrigonia s. str. in many characters as
described later. being distinguishable
from the subgenus Rinetrigonia in nothaving discrepant costae on the flanks.
In Japan Pterotrigonia .~. str. is well
represented by seven species from theCretaceous formaL ion (KOBAYASHI and
NAKANO, 1957. 1958, NAKANO, 1960).
The present specimen of the trigonid
shell from the 1'vliocenc \Iisaki Formation is closely related to P. lzokkaidoana(YEilAI~A) as described later. though it
seems to be an immature form.
As mentioned above. the present
specimen is morphologically a typical
Pterotrigonia s. sir. which is cosmopolitan in the Lower to ".t\Iiddle" Cretaceous of the eastern hemisphere excluding Australia. "\Iiddle" to Upper
Cretaceous of North and South America,
and Europe (NAKANO and NUMANO, 1961).
I\one of its members, however. havebeen reported from Post·Cretaceous deposits of any country. Although thepresent specimen was collected from amarine formation of Miocene age, it
seems to be more reasonable to consider

47;J.

25!)

Trigonid from the Mi.sald Formationthat the specimen was derived from a
Cretaceous deposit rather than to interpret it as a relict species.
Pterotrigonia hokkaidoana is widelydistributed in the Lower and .. tvliddle"
Cretaceous rocks in japan (KonAYASHI
and NAKA:-<0. 1957, 1958, NAKAi\0, 1960).
The occurrence of P. Jwkkaidoana from
Cretaceous formations nearest to 1\isaki.
is the Sanchu graben in the Kanlo
massif (Y ABE. NAGAO and SHIJI.IIZU.
1926), about 120 km norlhwest of 1\lisak i.
Another fossil locality of Cretaceous
age which yielded trigonids similar tothe present one is the Choshi peninsula,
about 130 km northeast of ~lisaki, from
where P. pocilliformis (YOKOYAt\IA) has
been reported (YA:\>IANE. 1921) (Fig. 2).

from l\lisaki. Therefore, it is inferredthat there may haYe been exposed Cretaceous deposits bearing such fossils as
Pterotrigonia near ~vlisald during the
Miocene I~poch.
Description
Subfamily Pterotrigoniinae
VAN HOEPEi\,

1929

Genus Pterotrigmzia VA~
HOEPE~,

1929

Pterotrigonia cf. hokkaidoana(YEHARA)Pl. 37, tigs. 1-3.
Compared with:.....:

a

-t-

1915.

1923.
~..

1923.

__

0....._

_,_

1926.

___.
IOOkm

Fig. 2. Localities of the Cretaceous
formations which yielded I'terolrigrmia(A, B), and the Cretaceous and the un·
known Me~ozoic or Paleogene formations(a. b) in the Kanto region.
A: Sanchu graben.
B: Choshi.
a: Kobotoke Formation.
b: Mineoka Formation.

Judging from the degree of the preser·
Yation of the specimen. it seems possiblethat it may have been reworked fromsome Cretaceous deposits not so remote

1931.
1957.

1958.

Trigonia hokkaidoa na YEHARA, Sci .
Rep. Toholw imp. U11i1• .. Vol. 2. No.
2, p. 39, pl. l. figs. 1-8.
Trigonia hokkaidoana YEHARA. foul·.
Ceo/. Soc. Tokyo, Vol. 30, p. 5-6, pl. 7,
figs. 3-5.
Tri,gonia hokkaidoana YEI!ARA, fapall.
four. Ceo/. Ceogr .. Vol. 2, No. 3. p.
70-71, pl. ll. figs. 9-10, pl. 12, fig. 5.
Trigonia l10kkaicloana? YABE. NAGM>
and SIII:\ttZlJ. Sci. Nep. Tolzoku lmj>.
Uni1·., Vol. 9. No. 2. p. 46-47, pl. 1-1.
fig. 3 .
Trigoniu lzokkaidoana YEHARA. Trigo·
niae from Japan, p. 15-17, text-fig.
Ptcrotrigonia I/Oklwidoana Kon.-\YAsllt
and N'At-:A:-;o, Japan. four. Ceo/. Ceogr.,Vol. 2o, ~vo. 4. p. 229-230. pl. 16. fig. •1.
Pterotrigonia hokkaidoana KonAYASIII
and ~AKA:-\0. Ibid .. Vol. 29. 1Vos. 1-3,
p. 1·18, pl. 9. figs 9-11.

De.~cription :-Shell small in size. subcrescentic. inflated anteriorly. produced
and slightly attenuated posteriorly; anterior margin rounded. passing gradually into gently arcuate ventral one:siphonal margin rounded; dorsal margin

260

Yasumochi MATOBA

long and concave. Umbo small, prominent, opisthogyrous. and pointed at afourth from the anterior end. Carinae
obsolete except near umbo. Escutcheon
broad, slightly depressed. with about 10
tuberculate transverse costellae: costellae
arranged more closely near umbo. Area
narrow and raised, narrower anteriorly
but wider posteriorly, provided with a
few transverse costellae in early stage;
median furrow shallo·w. not so distinct.
Flank with 15, tuberculate diagonal
costae; four near umbo concentric: next
six on most inflated part. slightly
curved and oblique anteriorly: last thestraight and oblique posteriorly.
Length 24 mm. Height 15 mm.
Remarks:- The specimen describedhere is a right valve and fairly wellpreserved. Its ventral margin and somecostae on the most inflatE:d part of theflank are broken. It seems to be an
immature form because of its small
size, so therefore it may have nearly
indistinct median furrow and rather
few costae.
P. hokkaidoana is very similar to P.
pocilliformis (YOKOYAMA). but the former
is distinguishable from the latter in its
tall and subcrescentic to trigonal outline
and more numerous costae on the flank.
The present specimen has not so many
costae as the typical P. hokkaidomw,
but the intercostal spaces of it are narrow as in P. hokkaidoana. It is comparable \\·ith Pterotrigonia lwkkaidom;a
CYEHARA) in many features. Especially
it resembles to the syntype of fig. 2
CYEIIARA. 1915, pl. l) except for the
narrower umbo and the larger size ofthe latter. On the other hand, the present specimen is more related with thesyntype of YEHARA (pl. 37, figs. 4a and4b) which was collected from the same
locality but different horizon. as that of

the specimens illustrated in figs. 1 and
2 (YEHARA, 1915. pl. 1), in its outline
and costal arrangements.
The specimen in fig. 5 illustrated by
YEHARA (1915. pl. I) has been questioned
by authors and sometimes even regarded as another species. KOBAYASHI and
NAKANO (1957) considered that it resembles P. pocillifonnis yamanokamiensis
KOBAYASHI and NAKANO from its elongate and rostrate outline. While N AKA·:\0 and NUMANO (1961) stated that it issimilar to certain P. brevicula (YEIIARA)
rather than the typical P. hokkaidoana
from its narrow area and sinuation on
the ventral part. However. from thewriter's observation on the syntype of
Trigonia hollkaidoana YEHARA preservedin the Institute of Geology and Paleontology, Tohoku University. the specimen
illustrated in fig. 5 (YEHARA. 1915. p. 1)
is poor in presen·ation. and its posteroventral margin is slightly broken as
seen in the figure. therefore it is notadequate to argue the taxonomic position of the specimen merely from its
vague outline.
P. hokkaidoana is widely distributedin the Lower and " i'\'liddle"' Cretaceous
formations in japan (NAKAKO. 1960).
Although Pterotrigonia has been known
to extend up to the late Cretaceous inNorth America and New Zealand, noneof its members are known from the
Tertiary and the later deposits of theworld.
Occurrence :-Calcareous conglomeratic
sandstone which yields abundant molluscan shells. the uppermost part of
the Lower :.lisaki Formation, at theeast side of the l'vlisaki harbour. l'vlisakicho, Miura City, Kanagawa Prefecture.
The geologic age of the .t\lisaki Formation is considered to be Middle ofLower .tvliocene.

47:3.

Triyonid f1·mn the Misaki Fonnation

IGPS coil. cat. no. 85720.
Heferences
CossMA:-;. M. (1912): Sur t·evolution desTrigonies. Ann. Paleont., Tom. 7. Fasc.
2, p. 57-8-t, pls. J ...!,
Cox. L. R. (1952): Notes on the Trigoniidae.
with Outlines of a Classification of the
Family. Proc ..l!alacol. Soc. London, Vol.
29. Pts. 2-3. J>. ·15-70. pis. 3--t.
CRICK:-.1.-\Y, C. H. (1932): Contribution• to·wards a :Monograph of the Trigoniidae.
l. Amer. four. Sci .. Vol. 24. 1Vo. J.J.f, p.
443-·16•1. pls. 1-2.
DF:ECKE. W. (1925): Trigoniidae Mesozoicae.
Fossilium Catalogues, Animalia. Pars :JO,
p. 1-306.
VA:" HoEPE:-;, E. C. N. (1929): Die Krytfauna
van Soeloeland. I. Trigoniida2.
Pal.
.Varorsing Nas. ,\Jus. Bloemfontein. Vol.
1. Pt. 1 (non t:itli.).
]!~lBO, K. (189·1): Beitrage zur Kennl ni,;sder Fauna dcr Kreideformation von llokkaid6. Paleorrt. Abh. /James u. 1\.aSl'l'.
Bd. 6 (lli. F. JJJ. 2), lit. 3. p. 149 I 9·1.
pis. 17-25.
KoBAYASHI. T. (1954): Studies on the Ju·
rassic Trigonians in Japan. Pt. I. Pre·liminary ;o..;otes. Japan. ]our. Ceo/. Geogr.,Vol. 2:J, 1\los. 1-2, p. 61-80.
- - and NAKA:-Io. l'v!. (1957): On the Pterotrigoniinae.
Ibid., Vol. 28. No. 4. i>·::!19-238. pls. 16-17.
- - and - - (1958): The Lower and !VIid·
die Cretaceous Trigonians in \Vakayama,
Oita and Kumamoto Prefectures. Westjapan. Ibid., Fol. 29 . .\'os. 1-3, p. 139152, pis. 11- 12.
LYCETT. J. (1872-79): A Monograph of the
British Fossil Trigoniae. Paleont. Soc.,
London. p. 1-215. pis. 1-H.
MATSDIOTO. T. el a/. (1953): The Creta·
ceous System in the Japanese Islands.
japan. Soc. Promotion Sci. Res. Tokyo, p.
1-324. pis. 1-20.
XAGAO. T. (1930) :On Some Cretaceous
Fossils from the Islands of Amakusa.
Kyushti, Japan. ]tlur Fac. Sci. Jioklwido

2Gl

Imp. Uni11., Ser. '1. Vol. 1. No. 1. p. 125. pis. 1-3.
~AK.-\:-;o, M. (1960) : Stratigraphic Occur·
rences of the Cretace:>us Trigoniids in
the Japanese Islands and their Faunal
Significances. ]our. Sci. Hiroshima Uni~· ..
Ser. C. Vol. 3, No. 2. p. 215-280, pis. 2330.
- - and NuM.\KO, K. (1961) : On some
Gyliakian Pterotrigoniae from Kyushu
and Hokkaido, Japan.
Trans. Proc.
Palaeont. Sac. japan, N. S., :Vo. 43, p.
89-98, pl. 13.
STOLICZKA. F. (1871) : Cretaceous Fauna ofSouthern India. Palaeonl. Indica, Ser. 6.
Vol. 3. Nos. 1-4. p. 1-537, pls. 1--50.
Ust;J. ]. (1952):
Geology of the .Miura
Peninsula. Ins/. Geol. Paleonl .. Tolwku
Unir .. Graduation Thesis (in Japanese,MS).
YAnE. H. and ~AGAO. T. (1925): New or
Little-known Cretaceous Fossils fromXorth Saghalin (Lamellibranchiata and
Gastropoda).
Sci. Rep. Tohoku Imp.
l!ni1• .. 2m! Ser .. Fo/. 7. JVo. ·1, p. 111124, pls. 28-:29.
- - , - - and SHJ~I!Zl!. S. (1926): Cretaceous Mollusca from the Sanchu-Graben
in the K wan to 2\1ountainland. japan(Lamcllibranchiata). Ibid .. Fol. 9, .Vo.
2. p. 34-76, pls. 12-15.
YA:>.JA:-;E. S. (1924): Explanatory Text of
the Geological Map of Japan. Scale
1:75.000, Chc'J:;hi. Geol. Surt•. fajJaiJ.
Y~rliAR.\. S. ( 1915) : The Cretaceous Trigo·
niae from Miyako and Hokkaido. Sci.
Rep. Tolzoku Imp. Uni1· .. 2nd Ser., Vol.
2. ,vo. 2. p. 35 .. 44. pis. 1-2.
- - (1921) : On some New Species of
Trigo11ia from the Lias of Prov. Nagato,
and the Cretaceous of Prov. Awa. }our.
Ceo/. Soc. Tokyo. Vol. 28, p. 7-11, pl. 5.
- - (1923a) : Cretaceous Trigo11iae from
Amakusa Island. Prov. IIigo, Kytishii,japan. Ibid., Vol. 30. p. 1-12, J>ls. 4-7.
- - (1923b) : Cretaceous Trigoniae fromSouthwestern japan. Japan. jour. Geol.
Geogr., Vol. 2, No. 3. p. 59-84, pis. 8-13.
- - (1927):
Faunal and StratigraphicalStudy of the Sakawa Basin, Shikoku.

Yaswnoch1: M.4TOBA

2G2

Ibid., Vol. 5, Nos. 1-2, p. 1-40, pis. 1-5.
- - (1931): Trigoniae from japan. Jwanami Lecture Series. Geology and Paleontology. p. 1-25 (in japanese).
YoKAYOMA, M. (1891): On some Cretaceous
Fossils from Shikoku. jour. Col/. Sci.
Imp. Uni11. Tokyo, Vol. 4, 1'1. 2, p. 357 ·

366, pl. 40.
S. (1902): Problems on the
Geology of the Miura Peninsula ofTokyo. jour. Geol. Soc. Tokyo, Vol. 9,
No. 100, p. 1-20, pl. 2. No. 101. p. 768•1. pl. 3 (in Japanese).

YosuJWARA.

SanchuMisaki

Explanation of Plale 37
Figs. 1-3. Pterotrigonia cf. ltokkaidoana (YEHARA).
la-c. Right valve (x3). 1\lisaki Formation (Miocene). Misaki-cho, Miura City, Kanagawa Pref. IGPS coli. cat. no. 85720.
2a-b. Same specimen in natural size.
3. Teeth of the same specimen (x5).
Figs. 4-5. Pterotrigonia ltokkaidoana (YEHARA).
4a-b. Right valve (X 1), syntype; not illustrated by YEHARA.. Lower Astarte Zone.
Hiraiga I. .Miyako City. lwate Pref. IGPS coli. cat. no. 4225.·
5. Right vah·e (X 1). synlype; the same specimen in f1g. 1 illustrated by YEIIARA (1915,
pl. 1). Cucullaea Zone. Hiraiga I. .Miyako Cily. Iwate Pref. IGPS coil. cat. no. '1335.
Figs. 6-7. Pterotrigonia pocil/iformis (YoKOYAI\IA).
6. Internal mould of a right valve (xl). Nagasaki quarry, Choshi City, Chiba Pref.
IGPS coli. cat. no. 35064.
7. Clay cast of a left valve (xl). So-yama, Kureta-cho. Nangoku City. Kochi Pref.
IGPS coil. cat. no. 22072.

MATOBA:

Trigonid from Misaki Formation

2a

2b

lc

KUMAGAI

photo.

Plate 37

Trans. Proc. Palaeont. Soc. Japan, N. S., !\o. 55, pp. 263-270. pl. 38, Sept.. 20, 1964

474.

DISCOVERY OF A FOSSILS J>EROTROCHUS IN THE
MilKE COAL-FIELD. KYUSHU. JAPAN*
1-IIDETAKA KURODA
Prospecting Section. Miike Colliery, Mitsui Mining Co. Ltd.

and
1-IIDEO URATA
Department of General Education. Kyushu University:fLi-H=::J!l!~Ffl~V.1Ht~ 1 ~fi:

:fLfli::::=;ill.~!UtO~·;bv~J.)~:>l:1t:t:il\"'IJ·~. Perotroclws
Perotroclws eocenicus c1i'tf:g-t7.>" lnl~fttit>:."?\,•cfi. B*il·i?'±~r~==~t.J.~if.n· ~, t.n ·~ t:-At.
~?-r. Mlt/iflttO ~ co;J:¥f!'...~ ~n7.> tOii.Lfl!!ln·;J&:f;J-ca:, 7.>

tOt/itdl:'H~~JL~ttt.:.co-c·-no0

ffiffl*F&·nllm~~

We wish to offer our best thanks lo
Professor 1-Iisamichi MATSVSIIITA, Professor Ryuzo TORIYAMA. Assistant Professor Ryohei TAKAHASHI and AssistantProfessor Tsugio SJHJTO. of the Department of Geology, Faculty of Science,
Kyushu University, for their kind advice
and encouragement and for reading themanuscript. We are also greatly indebted to Dr. L. R. Cox. of the British
l\'luseum. London, Dr. Tadashige HABE.
of the Natural Science l\luseum. Tokyo,
and Dr. Saburo KANXO. of the Instituteof Geology and Mineralogy, Faculty of
Science. Tokyo University of Education,
for their very helpful advice and kindsuggestions concerning the biological,
ecological and systematic problems andfor reading the typescript. Finally,
particular thanks are due to !'vir. Akira
ISHIDA. of
the Miike ~1ine, !vlitsui.tvlining Co. for allowing us to study
his collection.

Introduction and Acknowledgements
The Miike Coal-field of the southwestern part of Fukuoka Prefecture.
Kyushu. consists of lower Paleogene
formations, in which four fossil beds
were recognized by l\IATSUSIJITA (1949).
Although many fossil molluscs havebeen known to occur in these fossil
beds. no fossil pleurotomariid hashitherto been reported from Kyushu orfrom Paleogene formation in any otherpart of Japan. We have recentlv founda rare but interesting pleuroto~ariid in
the lower Nogata fossil bed in the Kat·tachi formation. This paper consists ofa description of the newly discovered
pleurotomariid together with discussions
on the characteristics and significanceof the fauna.
* Recei\'ed June 15. 196-t; read Sept. 29,
1962. at Tokyo.

2G3

2G4

Hide/aka KURODA ancl Hideo URATil

Geological Occurrence andCharacteristics of the
Kattachi Fauna

The Eocene Kattachi formation, thelowest member of the !\Ianda group, is
distributed widely in Omuta City, Fuku·

Text-fig. 1.

oka Prefecture, and mainly crops out inthe neighbourhood of the Kattachi mine
and in the southern to southwesternarea of the Nanaura mine of the .\litsui!\lining Co. It consists mainly of sandstone with intercalations of glauconitic
sandstone. sandy shale and shale in the
Kattachi area.

Map showing the geographic position of the fossil locality.

In the lowest part of the formation,coarse-grained glauconitic sandstone
with greenish grey calcareous sandstone
is developed and yields many fossils. The
Kattachi formation gradually merges
into the underlying Nanaura formation,
which comprises mainly bluish or lightgrey sandstone and conglomerate, andis overlain conformably by the Yotsuyama formation. consisting of dark grey
fine-grained fossiliferous sandstone withintercalations of glauconitic sandstoneand shale.

The fossiliferous part of the Kattachi
formation is called the Kattachi fossil
bed, in which we have found six pelecypods, three gastropods and one
brachiopod, besides specimens of corals
and sharks' teeth. These fossils are:Lima nishiyamai (YOKOYAMA), Pholadomya sp., Br.1ehidontes sp., Crassatellites
nipponensis YoKOYA~IA, Fenericardia
nipponica (YOKOYA1viA), ll. cfr. mandaica (YoKOY A~IA), Perotrochus eocenicus
KURODA and URATA, n. sp., Pseudoperisso[ax yokoyamai SUZUKI and ITO,

47 4.
Colus

sp.. Carcharias
and corals.

Discovery of a Fossil l 1emt1·ochu.~

cfr. cu:;pidatus
In addition to(AGASSIZ)

m mudstone 8 shale~ sondy shaleDsandstone[I] coarSB-grained ss.
~ conglomerofe
-cool
i<

fossiliferous bed

NoGATA

Fossn
BED

2115

them, according to YoKOYA~IA (1911)
and NAGAO (1928). Neptunea ? sp ..
Volutilitlzes ? sp. and Aluria nagaoi
KonA Y ASH!
were discovered at thesame horizon.
The above-mentioned fossils arepreserved mostly as separated valves.
some more or less broken individuals
being slightly deformed secondarily.
The surface of the fossils. except the
sharks' teeth, is frequently worn.
Cra:;salellites nipponensis and Venericardia nipponica are predominant in thepresent fauna and the innumerable individuals of the former species often
occur in swarms. almost to the exclusion of any other fossils.

Short Note on the Pleurotomariid
Gastropod
According to KURODA and HABE {1952).
fl955). HIRAYAMA (19551, KIRA
(1959) and HABE (1961). eight species ofliving Pleurotomariidae, belonging tothree genera. are known in the world,and five species. representing three
genera. are recorded from the seasadjacent to Japan.
The japanese
species are: Perotroclw:; teramachii
KURODA. Milwdotrochus beyrichi (HIL·
GE:\DORF).
M. lzirasei (PILSBRY). A/.
salmiana (ROLLE) and Fntemnotrochus
rumphii (SCHEP~IA:"\). The localities of
the Japanese species are as follows :KURODA

50

OM

Text-fig. 2. Columnar section of the
Omuta and the Manda groups in the
Miike Coal-field.

P. teramachii
M. beyrichi

p: 33*
p: 29?-35

M. llirasei

M. salmia11a
E. rump/iii

p: 33-3-!
p: 0-33

Off Tosa(100 fms.)
Off Choshi. Sagami Bay and western
coast of Kyushu(150-350 fms.)
Kii Channel. Tosa Bay(100-150 fms.)
Off western Kyushu(ca. 3 fms.)
Off Tosa and Sagami Bay(150 fms.)
Off Tosa (Formosa. East-lndie:;)* After KuRoDA and liABE (1952b)

Hidetalw KURODA and J-lideo UR;lTil

Though they are generally considered
as deep-sea inhabitants. a few specimensof the species listed above have beencollected from rather shallow sea bot·toms. KURODA and IIATlE (l952a} havereported living M. beyrichi from a depthof about three fathoms, off the west
coast of Kyushu. The living immatureindividual of the same species collected
and reported by NnNo (1955} camefrom the banks near the Izu Islands,
50-90 fms. in depth.
" Pleurotomaria " have been recorded
from formations ranging in age from
Paleozoic to Recent. But the family
Pleurotomariidac SWAINSON, 1810, as
restricted in the " Treatise on Inverte·
brate Paleontology .. (!VIOORE eel., 19601,
includes 11 genera and ranges from
Triassic to Recent. Among the genera.
Perotrochus ranges from Oligocene to
Pliocene and Recent, Milwdotroclws
from Pliocene to Recent, and Enlemnn/rochus from Eocene to Miocene andRecent (lvloORE eel.. 1960}.
In japan, two Paleozoic pleurotomariid
species were reported by I-lA YASAKA(192-1, 19113): the one, "Pleurolomaria"
cfr. carina/a So\\'ERBY. was found in
the Omi Limestone, Niigata Prefecture,and the other, •· Pleurntomaria" yoko·
yamai HAYASAKA. in the Permian" Black Zone" of the Kinshozan area,
Gifu Prefecture, but no pleurotomariid
has been found in thei\1esozoic* andI
Paleogene formations.
On the other
hand, five species of pleurotomariids
have been collected from the Neogene
deposits. They are: Perotrochus yosi·• According to KA:-::-<o (private communi·
cation), "Pleurolomaria" sp .. reported by
NAGAO (1963) from the Hetonaian Akkeshi
alternation. is a single :Mesozoic pleurotomariid of Japan. The specimen is now
under inYestigation by KA!'NO.

warai (OZAKI), P. aosimai OzAKI, P. otoensis KAN~O, Mikadotrochus yabei (No1\JUI~A and NIJ:\0) and M. prope-hirasei(OZAKI).
1'. yosiwarai, P. aosimai and M. propehirasei were obtained from the basal
conglomerate of the lower Pliocene
Naarai formation. Chiba Prefecture(OZAKI, 1%1, 1958). P. otoensis is reported from the coarse-grained sandstone of the I\1ioccne Kobana formation.
Tochigi Prefecture (KANNO, 1961) andJ\1. yabei. from the very coarse-grainedsandstone of the I\liocene Shirahama
formation, Shizuoka Prefecture (NoMURA
and NIINO, 1932).
Besides these, IIIRAYAMA (1955) described an unidentified species of Perotrochus, but according to KANNO (1961),
it seems to be conspecific with P. oloensis.
KuRODA (1955) states that M yabei
seems to bear a close resemblance to
M. hirasei.

Additional Note on the Ecological
Environment of Fossil
Plcurotomariids
It is well known that pleurotomariid
gastropods now nourish on deep sea
bottoms where gravel and coarse sandarc distributed and where the innuenceof a warm current is felt. The only
two exceptional cases of pleurotomariids
occurring in shallow water are the examples from western Kyushu and fromthe bank near the lzu Islands.
On the other hand, the rocks and thefossil faunas in which pleurotomariids
occur do not indicate such deep-waterconditions.
IIAYASAKA (1953) stated that the Permian Kinshozan fauna \Vhich includes" 1'/eurotomaria " yolwyamai represents a

.4 7.!,.

Di scovenf of a Fossil Pe~·otroch ns

shallow sea environment, and further YABE (1936) considered that it suggests thesapropel deposits of mangrove swamps.
ScHE:\CK and KEE:\ (1958) are ofopinion that the Danian pleurotomariid
from Denmark may not have been an
inhabitant of very deep-water becauseof the similarity between it and Entemnolrocltus adansoniana (CROSSE andFISCHER). which was dredged from off
Barbados in 60 fathoms.
OzAKI (1954l supposed the sedimentary
environment of the Naarai formation tohave been the gravelly bottom of anopen sea about 200m. deep. influenced
by the Kuroshio.
According to HIRAYAMA (1955), theassociated fauna and lithofacies suggestthat the tvliocene deposits from which
Pero/rocllll s sp. was collected represent
a shallow sea environment.
On the other hand. KA:\NO (1%1)
mentioned that. though Haliotis and!Jiodora ? arc found in the fauna. themolluscs. including Perolrochus otoensis,
are somewhat deep-sea inhabitants.
" Because of the few number of individuals and fragmental preservation of
the just mentioned littoral molluscs(l!aliolis and Diodora ?). it is inferredthat they were removed from the shallow sea bottom to a rather deep one.
The other molluscs associated with
Perotrochus are Cydopec/en. Cuspidaria,
Fulaoraria and brachiopods such as
Dal/ina. Terebratulina and 1\amoica allof them are usually rather deep-sea
inhabitants."
Our new pleurutomariid specimens
were collected from the lowest horizonof a very coarse-grained glauconitic
sandstone occurring 60-70 m. above thecoal seam Uo·so) of the Nanaura formation. This glauconitic sandstone isabout 45 m. thick and passes up into

267

non-glauconitic coarse-grained sandstone,
and about 25m. above the top of theglauconitic sandstone the main coalseam (Daini Jo-so) of the Kattachi formation is developed.
According to YAGI (1932). glauconite
is now being formed in the littoral tobathyal zone where warm and cold
currents meet.
Among the associated molluscs, Crassatellites and l' enericardia indicate aneritic environment. but Pho/adomya,
Lima and Co/us are rather deep-sea
inhabitants.
From the above discussion, it appears
that the Kattachi fauna may be subneritic or bathyneritic and the rapid
subsidence of the basement of the Kattachi formation might have taken placein the ~liike Coal-field in the samemanner as pointed out by KAt-:t-:o (1961)
in the Kobana formation.

Description

Family Pleurotomariidae
Genus Perotrochus FISCIIEI~. 1885
Type species: Pleurotomaria quoyana
FISCHER & BERNAIWI. Recent in the
Caribbean.
Perotroclws eocenicu.'> KuRODA& URATA, n. sp.
Pl. 38. ftg!>. la. b. c. 2a, b. 3. 4, 5.

Material :-Holotype: GK-L 5163 IColl.
by Akira lSIIIDA). Paratype: GK-L 5164
(op. cit.).
Description:- Shell rather thick. of
medium size. turbiniform. broader thanhigh ; apical whorls broken. but 3.5
whorls observable. separated by shallow
but well-defined sutures, somewhat

2G8

Hidetaka f{URODA. and HideJ URA.TA

shouldered. moderately convex, last one
subangular at periphery of base; selenizone just below mid-whorl. somewhat
raised from shell surface and with 4
spiral striations separated by very
shallow and narrow. sometimes obscure
grooves: ornament fine cancellating
spiral and collabral striations; spiralstriations predominant between lower
margin of selenizone and inferior sutureand 6 in number on penultimate whorl,
but very weak between upper marginof selenizone and superior suture; collabral striae oblique and strong above

the selenizone and vertical, slightly convex in adapertural direction and rather
obscure below the selenizone: slit unobservable, base slightly swollen. withnumerous spiral lines which are crowded at marginal area but gradually
become sparse tow·ards the umbilicalregion. and are crossed by numerous
very fine concentric growth-lines slightly
convex in adapertural direction. Umbilical region not known in detail because of extreme hardness of motherrock, pseudumbilicus possibly present.
Aperture broken.

Dimensions:Height
Maximum diameter
Minimum diameter\Vidth of sclenizonc
Apical angle
Incremental angle

Holotype
60 mm. (e3timated)
72.0111111.
60.5111111.
1.6 mm. on Lhe last whorl

1.6 mm. on the last whorl
1.2 mm. on the penultimate whorl

100"
85"

Type locality and horizon :-Roadside.
1 km. ENE from the Kattachi mine,
Shimo-takata. Omuta City. Fukuoka
Prefecture. Lower Nogata fossil bed,basal part of the Kattachi formation,
Manda group.
Distribution:- Only known from thetype locality.
Comparision:- This new species isdistinguished from all previously known
japanese Cenozoic pleurotomariids by
its characteristic surface ornament. consisting, as described above. of strong
collabral and weak spiral striations
above the selenizone, and of weakcollabral and strong spiral striations
below it. This character is not seen
in other Cenozoic pleurotomariids at
all, but is clearly observable in the
Permian " Pleurotomaria ·· yokoyamai
1-IAYASAKA.

Para type
50 mm. (e·;tirnated)

According to Cox*. there is anotherspecies which is of the Oligocene or the
lower i'vliocene in age, Perotrochus allani
MARWICK,
reported from \Vaikaripi,
Chatham Island, New Zealand. This
species shows some similarity to our
new species, but the former has a slitband situated at about median part of
the whorL and as ornamentation, it
shows spiral cords.
References
HABE, T., (1961) : Coloured Illustrations of
the Shells of Japan (II).
Hoikusha,
Osaka. (in Japaneae)
HAYASAKA. I., (1924): On the Fauna of the
Anthracolithic Limestone of Omi-murain the 'Vestern Part of Echigo. Sci.
Rep. Tohoku Imp. Unit• .. 2nd ser. (Ceo/.).

* Private communication.

47 -~.

Liscovc·ru of a Fossil rerotrochlls

1•ol. B. no. 1.
- - (1943): On Some Permian Gastropods
from Kinshozan, Akasaka·machi. Gifu
Prefecture, Part I (the only part pub·lished). Mem. Fac. Sci .. Taihoku Imp.
U11i1•., Taiu·an, ser. 3. t•ol. 1, no. 2.
- - and IL.,YASAKA. S .. (1953): Fossil Assemblagea of !\Iolluscs and Brachiopods
of unusually large Sizes from the Per·
mian of Japan. Trans. Proc. Palaeo11/.
Soc. japan. N. S., 110. 10.
HIRAYAMA. K., (1955): Discoyery of Pao/rocltus in the Miocene Deposits ofTochigi Prefecture, Japan. jour. Mal.
Soc. japan (The ~·enus). z·ol. 18. no. 4.
KA!';NO. S .. (1961) : Miocene .. Pleurotomaria ..
and its Associated Fauna from Tochigi
l'refecture. Japan.
jap. jour. Geol.
Geogr .. vol. 32, no. 1.
KmA. T., (1960): Coloured Illustrations of
the Shells of japan (I). En\. & Rev.
Ed .. Hoikusha. Osaka. (in Japanese)
Kt:RODA. T., (1936) : A Recent Pleurolomaria
new to the Japanese Fauna. jour. Mal.
Soc. japan (The Venus). l'ol. I, 110 • .f.
(in japanese)- - (1955): A New Pleurotomaria fromjapan. with a ~ole on a Specimen of
P. rumplzii ScHEI':>.tA:-: collected from
Taiwan. Ibid .. vol. 18. no. 4. (in Japa·ncse)- - and IL\BE, T .. (Hl52a): A Xew Localityof Perotroclws hirasei. Ibid .. t•ol. 17. 110.
1. (in Japanese)- - and - - (1952b) : Check List and Bibliography of the Recent 1\Iarine i\Iollusca ofjapan. Leo. \V. STACH Ed., Hosokawa
Printing Co .. Tol1yo.
MATSL:SHITA, II .. (Hl·19): Geology of theCoal-fields in Northern Kyushu. Res.
Bull. Fac. Sci. 1\yusltu Uniz· .. (Geol.).
vol. 3. no. 1. (in japanese)
MooRE, R. C .. (Ed.) (1960) : Treatise on
Invertebrate Paleontology. Part I, Mollusca I.
Uniz•. 1\.ansas Pr. and Geol.
Soc. America, ,'I/ etc York.

2(iH

NAGAO, S.. (1963): Explanatory Text of
the Geological Map of Japan. "Toko·tan." Geol. Sun•. Hokkaido. (in Japanesewith English re;;umc)
1\.-\GAO, T., (1928) : Paleogene Fossil:; ofthe bland of Kyushu, Japan. Sci. Rep.
Tohoku Imp. Unit•., 2nd ser. (Geol.), t•ol.
9, 110. 8.

:;\ti:"O, H.. (1955): On a l\Ianganese :\'oduleand Perotrochus dredged from the Bank
near the Izu };;lands. Japan.
Rec.
Oceanogr. Wlzs .. japan, t•ol. 2. no. 2.
No~H'RA. S. and Nmm. I-1, (1932) :FossilMolluscs from Izu and Hakone.
Sci.
Rep. Toltoku Imp. Uniz•., 2nd ser. (Geol.).
z•o[. 15, no. 3.
OzAK 1. H., (195·1a) : On the Paleontology of
the Ba:;al Conglomerate of Pliocene in
Tyo:;i City, Kanto Region. Bull. Nat.
Sci. Mus .. :\". S., z:ol. I. no. 1.
- - (195•lb): Straitigraphy of the Basal
Conglomerate of the Pliocene Naarai
Formation in the Tyo.;i City. Kanto
Region. Ibid .. z•ol. I. no. 2.
- - (l\J58);
Stratigraphical and Paleon·
tological Studiec; on the Neogene andPleistocene Formations of the Tyosi
District. Ibid., t·ol ..J. no. 1.
SctrE>;cK. II. G. and KEE:". A.M., (1939): An
Index Method for comparing Molluscan
Faunules. Proc. Am. Plzil. Soc., 1•o/. II,
110, 2.
- - and Ml'LLER, S. 1\1., (1943): Standard
of Cretaceous System. Bull. Am. Assoc.
Petro. Geol., !'ol. 2'7, no. 3.
YABE. II., (1958): Thick Limestones of theUpper Carboniferous and Permian Age
in japan: an Introduction of their Modeof Deposition. Proc. japan Acad.. vol.
3·1. 110. 4.
YAcr, T., (1932) : Glauconite. Itranami·Koza,
Iwanami. Tokyo. (in Japanese)
YOKOYA:-IA. M., (19ll):
Some Tertiary
Fossils from the Miike Coal·field. jour.
Col/. Sci .. Imp. Unit•. Tokyo. t•ol. 21, art.
20.

270

Hidetalw KURODA and Hideo UR.,1TA
Kinshozan
Shima-takata

KattachiExplanation of Plate 38
Fig. 1. Perotroclws eoce11icus KuRoo,\ et UR.-\TA, n. sp., Holotype. x 1. a. apertural view; b.
apical view; c. umbilical view.
Fig. 2. Perotroclws eoce11icus KuRODA et UR.-\TA, n. sp .. Para type, x 1. a. apertural view; b.
apical view.
Fig. 3. Portion of surface of Lhe Paratype showing the characteristic ornament above andbelow the cicatrix. ca. x2.5.
Fig. 4. Portion of surface of the external mould of the Ilolotype showing the characteristic
ornament. ca. x 1.7.
Fig. 5. Portion of basal surface of the external mould of the Ilolotype showing the ornamentation of base. ca. x 1.5.

K URODA and URATA:

Perotrochus from the Miike Coal-field

Plate 38

Trans. Proc. Palaeonl. Soc. Japan, N.S., No. 55, pp. 271-280, pis. 39-11, Sept. 20, 1964-!15.

A FIND OF SPU~GII t~H•RPHOIDS FROl\I THE CRF.TACEOUSSYSTK\I OF REBUN ISLAND AND THE ESASHI GROUP
OF THE ESASHI :VIOUNTAINS, HOKKAIDO"'WATARU IIASHI1\IOTO
Institute of Geology and Mineralogy, Tokyo University of Education

andSUTEKAZU NAGAO
Geological Survey of 1-lokkaido~tifliilitl~~Pl'iiHUo .1: .:,-:tJ<¥~lt.ttl!~f~#Jm!l'fil· >J Spongiomorphoids ~~5!: tl31.:
1::1 ~1,1;~~-? '5!lf!~'1tH?. fX'!1!1-JJ · A:~C-!<i.:. J:..., "'C. _l'.ffi>t'!'lti*C ,~ v .:. i!t~ ·J·;-t?tijE~~/H<;'J'.mU'~;h.t.:.n: . .:C~S}1!ii1.~?:ij~JHl~lctl\'la-!.f~.l.·t L.. ~~Hiii.l!llc~X.6ht..:..

Lb·L.l962

1'fc?t~IHL3l.:f:JcJJ!1l!'fft~cf·~1'i'fi· ·> t..:. t.:. 7;), iHI~f-:11\~"/ijf;J: 1J. ~ 6t.:..u;,:r.:.t>t.:.'5.!:.::.7;)/J·i?>hrf'l~f~ft.ii'i.'~jiLt.:..
-i"VC. 1~;].{~~~1/ti.::.-?~ -u.t.. i'i~·f'.'it~9.:~JOJ{,Q)t/.

'-1'··c~yOJ~It·:a-1JnX.'5t.!tt-cf!l!Hilll%:it/-.Q...:.
>a:-~'lh t..:.,
l*!JS Lf.:.{t.:riLI:.. Zam iopllyl/um? 'it'li:'r,~. ~·-?At{, :r,}'i:·tMUl!~~rlq.::.-;-,~ !Ut7.:> f:iYd':i'J.lf!

,,,:.:.~.ll~.ttt.:.:bQ)·('. l·i>:-J:>;o.~;Q)!i!:'rJ.'E~Ilft~ -;:;,.t j • ..:c ·j Lt.:.>!:.Q)~•h:. 2 A!1!i~.:. ~ f•l 1 161:iJ:':l~~~.'$i.::.rlri" '5 ..:. cit(:; L,',fffi·r:·. ;J:JJ 5G

Spongiomorphoids :f·~J! ~;tt f.:..

l>:,?':fi:f!!.l:'l";lliQ) Orbito/ina li:P:E~'·1ii·I?-£.JE~~ L ·n · 7.> :.::. i"§:'tJ:~ 'o tl~~-clt..-: v A
l11:c7)~j;fiil'fi.H'.h"'l'ili',~ I· flt:n · ~->.:. ~ f9%1t.n'H!. ~itt.:.·J~. -=i:-CI)tJ..J~-f!lH:tl ·b•J,7.>X':Q)m:riW<:!ti,,t~fiR;.:.[iiJJi:' ~tt... ft~Q)-tH,. Wrfil\-.::! :t:lb .~dJ'.f.!!~)-c.ilit -toRn·:J;, o · .:C.::. "C-i"h':~·;~;12~i"7..> c jl,:.::.. ;!;,;b·lt-C.i'1t01ll1i!!i!F.Q)..:: Q) 1'1•1:1!:.::. -?t · ·c >{,:it! Lt.:., ~ t.:..:::. 5 Lt.:. ftfii.:.[)\J)ill L"C.lt:if,Jjtlt.>·:?O)it!~H: L 1?"'. iillll\l'i''PI~,.:.~)l ·t:E:f),< Lt.:.
lilfi
Ji · J:i: );{! #i-*

upon the occasion of compilation of the
1:200.000 geologic map of Hokkaido,
the senior writer treated the same depositions as pyroclasl ic facies of the
Sorachi series of the J urasso·Cretaceous
age according to the junior writer's observation on it.
The senior writer had been thus in
two mind, due to the following points,
namely. l) the hasement complex of
Rebun island consists of heaYy effusive
rocks of porphyrite origin. 21 no fossil
had been recognized from it until that

Introduction
Nearly a decade ago, when the senior
writer compiled the geologic map of
1-lokkaido on the scale of l : 600.000. hetreated the basement complex of Re·
bun island as being of the Cretaceous
period according either to its strati·
graphic relation to the Tertiary systemor to the litho-facies described by F.
S.uo (l936. MS.).
However in l95i.
• Recei,·ed June. 23. 1964 ~ read Nov. 19,
1H61.

271

272

l•Vataru HASHIMOTO and Sutelw.zu NAGAO

time, 3) on the other hand in south
Sag hal ien to the north of this island,
there develops a well known fossiliferous
porphyrite pyroclastic formation. theRyugase. of Upper Senonian age ('I'.
l\1ATSU!\IOTO, 19~2-1943). while in thecentral meridional geotectonic zone of
Hokkaido there develops a thick effu·
sive facies of porphyrite in the lower
and the middle parts of the Shuyubari
formation of the Sorachi group. The
latter is considered to be of jurassoCretaceous age as judged by the presence of calcareous algae found within
it. (W. llASIIIMOTO. 1958a and l960a).
Very recently, C. AKmA and T. OMORI(1959) discovered Criocera:.; sp. from the
Jizoi\va formation of F. SATO. i\iloreover
T. MATSUMOTO of Kyushu University
stated that. he has been presented afairly good specimen of Pulche/lia obtained by T. OMORI from the same
locality through the courtesy of K.
T ANAKI\ of the Geological Survey ofJapan who examined the fossil locality
together with T. 0:\JORI.
Thus theBarremian age of the .Jizoiwa. thelowermost formation of the basement
complex of the island has been recognized.
judging from the report of AKIBA
and 01\JORJ, it seems to the present
writers that they considered the Cre·taceous deposits of Rebun island to belimitted to a small area covered by the
jizoiwa formation while nearly all of
the remaining area consists of various
kind of 1\l iocene deposits. such as so·called " green tuffs" etc.
In otherwords, they seemed to consider the remaining part of St\To's basement complex consisting mostly of porphyrite
pyroclastics to be of Miocene age, in·eluding Si\To's Tertiary green tuff.
It is a very interesting problem in

speculating upon the development of
the geologic structure of Hokkaido thatthe "lower Miocene green tuff .. formation which hitherto has been regarded
as the most characteristic member ofthe geotectonic zone of southwest Hokkaido and circum-Okhotsk rep;ion. o\·er·lies a basement complex of peculiar
facies compared with that of the above
mentioned areas. Therefore the senior
writer has been much interested in thestratigraphy of the island and had
tried to visit the island for geologicalsurvey. In 1962. he got a chance tofollow the junior writer who has been
engaged in field works for the publication of the geologic map of the island
for the Geological Survey of Hokkaido
with cooperation of r..tcssrs C. AKIBA, T.
Ol\IORI, H. OSANAJ and 1<. iviATSUSHITA.
The present writers' geological excurtion was successful for observationof the stratigraphy of the basement
complex of the island. They obtained
a plenty of individual tvlcsozoic fossils
from the horizon of much upper thanthe Jizoiwa formation where I3arremianammonites were obtained. Herein thefindings are described.
Before proceeding further. the writers
express their cordial thanks to Prof. l\1.
Ect:cHJ of Tohoku l'niversity for hiskind advice on the fossil spreactinids
and to T ..MATSU:\IOTO of Kyushu Uni\·ersity for his kind information onammonites from the island. Present
writers arc also much indebted to Dr. H.
OsAKA I and ~Jr. K. !v1ATSUSIIIT A of theGeological Survey of Hokkaido. to Dr.
C. AKIBA of Hokkaido Gakugei Daigaku
and to l\lr. T. 0:-.JORI of Utanobori Pri·
mary School for information on thestratigraphic relation of the Nairo formation described below.

475.

Sronaiomorphoids j1·om the Cretaceous System of Hokkaido

Brief Notes on the Geology
of Rebun Island

F. SATO (1936 l\lS.) established thefollowing stratigraphic order for thebasement complex of the island. in descending order ..
Nairo formation
Anama formation
Uennai upper formation
lower
Jizoiwa formation
According both to the present writers'
observations and to information giYen
by ~Iessrs. C. AKIHA. T. OMORI, H. OSA·
~AI and K. MATSt:SHITA. SATO's succession seems to be almost acceptable \vith
the slight modification described bellow.
Namely. the revised Jizoiwa formationis restricted to the part which consistsof agglomeratic rocks intercalating thinbedded greenish. tuffaceous mudstoneand sandstone layers from which. as
above mentioned two kinds of Barremian ammonites have been obtained.
Therefore, the upper part of SATO's
Jizoiwa formation illustrated in his geological map must be transferred to
the Uennai lower formation of revised
meaning. The thickness of the jizoiwa
attains 200m.
The revised Uennai formation consists mostly of pyroclastic sedimentof porphyrite eruption; it overlies the
Jizoiwa and conformably underlies the
Anama. The typical exposure is observed along the west coast of Rebun
island from Uennai southwards to justnorth of Jizoiwa. This formation is
subdivided into two parts: the lower
consists of greenish tuffaceous sandstoneintercalating tuff-breccia and agglomerate and attains 400 m in thickness; theupper consists of an alternation of Luff.

273

breccia and agglomerate which is characterized by small pieces of calcareous
remains of organisms or calcareous mud
scattered in the matrices of rock andattains also ca. 400 m in thickness.
The Anama formation consists of tuff.
breccia and intercalates fossil-plant-bearing sandstone and slate; thickness ca.
400 m. The type locality of this formation is on the Anamaiwa coast situatedat nearly 1 kilometer north of Uennai.
The Nairo formation of ca. 600 m thickness widely crops out along the east
coast of the island ; it consists mostly of
agglomerate. porphyrite blocks whichdisplay characteristic onion weathering
surface. intercalating some sheets ofporphyrite lava flow.
According to H. OSA'\AI, the Nairo
conformably overlies the Anama in thecentral part of the island. The Nairo
forms a broad and gentle folded svnclinorium with an axis almost parailel
to the direction of the island which embraces the Rebundake formation at its.
central part and includes the remaining
formation described above on its western flank.
According to C. AKIBA and T. OMORI,
the Rebundake formation consists mainlyof tuffaceous sandstone and tuff-breccia
in alternation and certain amount oflava flow of basaltic andesite. a part ofwhich. sometimes. grades into agglomerate. The present writers propose a
new name " the Rebun Group " for theabove described six formations, namely
the jizoiwa. Uennai lower. Uennai upper,
Anama, Nairo and Rebundake formations.
in ascending order.
Notes on Biota and Age
Consideration

The present writers obtained many
Mesozoic fossils from the Rebun group.

27-1

H"atant f!J!SHIMOTO and Sntekazn N;lr;Ao

exposed along the west coast of Rebun
island, those are: Zamiophyllum ? sp.,
Stromatomorpha rebzwensis n. sp., Spongiomorplw asiatica YABE and SUG!YAl\IA,Tlwmnasteria sp.. Sty/ina sp., Latomeandra ? sp., Polyphylloseris ? sp. cf. P.
iwatensis Ecvcm. Placocoenia ? sp .. besides calcareous algae, stromatoporoids
and others.
The first mentioned one was obtained
from the Anama formation and the rest
from the Uennai upper formation. The
impression determined as Zamiophyllum ?
sp. is not in sufficiently good preservation for determination of distinguishing point of this genus. However, its
general figure closely resembles thecertain part near the apex of this Bennettitales.
Zamiophyllum Buccian u m (ETTINGS·
HAUSE:\) 1\AT!IORST, the only one
species of this genus, is the typical
Wealden indicator in Europe and North
America. howeYer. in Japan. it ranges
from Cpper Jurassic to Upper Cretaceous. Although, Zamites Yahei Orsmof lower Jurassic is another allied formin Japan. the form of pinnule base andthe manner of its attachment to the
middle rachis of the present specimen
is quite distinguishable from that of z.
}'abei.
A spongiomorphoid is a typical .\lesozoic organism which flourished mostly
in the Triassic seas in foreign countries; therefore, it was the first recordof this organism from the Upper Jurassic when YMm and SUGIYAMA (1931)
described Stromatomorpha yokoyamai,Spongiomorplw asiatica and Spongiomorpha globosa from the Torinosu limestone of Japan.
Among many localities of the Spongiomorphoid-bearing limestone of Honshu reported by YABE and SIJGIY AMA,

the Torinosu limestone of "Sanchu
graben " in the K wan to ~Iountains wasconsidered by M. EGUCHI (1951) to be
Cretaceous in age due to the inclusionof the Cretaceous coral- Eugyra. However, no further argument on the geologic age of the limestone was carriedon and the editors of the 1 : 200.000 geologic map of Nagano Prefecture regarded the Naranokidaira formation which
includes the limestone under question to
be Upper Jurassic in age. In 1948, !\1.
EGUCHI reported Spongiomorpha miyakoense EGUCHI from the "Orbitolina sandstone" of Miyako, Iwate Prefecture.
This is the first description of a Cretaceous spongiomorphoid. Prior to that.
the first report of a Cretaceous spongiomorphoid was made by YARE and SUGIY A:\! A (1939b) on the existence of a species allied to Spongiomorpha asiatica
from the Orbitolina limestone of Hokkaido, but neither description nor illustration was attached to their statement.
They also reported the discovery of
Spongiomorpha asiatica from Iwachishi,
Hidaka Province, Hokkaido. which wassaid to be identical with the type specimen from the "Sanchu graben". According to T. NE:\fOTO, M. SAJ\Bo:>rsuGI
and B. MIZVGUCIII (1942). the lwachishi
sample was probably obtained from theSarugawa series which was correlatedby the senior writer (1959) to the Yamabe formation. the lower half of the
Sorachi Series ; both of these. especially
their upper part, are considered to beof Upper Jurassic.
Microsolena sp. reported by YAnE andStiGIYAJ\IA (1939b) from the Pepeshuru
Hivcr in lburi Province. Hokkaido presents feature closely resembling spongiomorphoid. The present writers. after
their studies on the Rebun specimen
described bellow, and some specimens of475.

Spongiommplwids j)·om the Cretaceous Syston q( Jlokkaido

Jficroso/ena from Honshu. are rather
inclined to consider that the lburi
specimen is hardly distinguishable from
Spongiomorpha and probably is conspecific with asiatica. lburi specimen
was obtained from the river floor of
the Pepeshuru River and is considered
to have been washed out from the··schalstein group" of the Sa ruga wa
Series.
Stromatomorpha
rebunensis
closely
all ics to Sl romatom orjJha yolwyama i,with which the writers once misidentified it (W. HASJII)IOTO and S. NAGAO.
1962;.. This new species was foundfrom the formation conformably superposing on the ammonite-bearing Jizoiwa
formation of Barremian age together
with Thamna!ileria sp., Po/yphyl/oseris ?
sp .. cf. P. izmtcnsis and other corals besides aboYe mentioned Spongiomorpha.
Recently, Y. TERAOKA obtained Stromatomorplw yohoyamai from the 1'\ikorogroup (W. HASHI:O.IOTO and Y. TERAOKA,
1962 !\IS.) in Kitami Province together
with Stromatoporoids of the Torinosu
and Ainonai clements (W. HASI-IL\IOTO,
1960c).
The Nikoro group intercalates the
Ainonai limestone in its southern extention and is considered to be equivalent to the 't'amabe formation to both
its lithic character and fossil evidence.
As already mentioned above. the so-called " Torinosu fossil elements" occur
not only in the Yamabc formation andits equivalents but also in such a higher
horizone as the Uennai upper formation
conformably superposing on the Barremian Jizoiwa.
Two forms of Thamnasteria were observed in thin section. This genus
ranges from i\liddle Triassic to l'vliddle
Cretaceous. Sty/ina ranges Upper Tri.assic to Lower Cretaceous. A specimen

275

resemblant to Latomeandra was obtained, which ranges from Middle jurassic
to Lower Cretaceous.
tvlany individuals of Po!yphylloseris
were collected from several places. but
no one preserves its external feature
which proYides the distinguishable character of this genus. The general features observed in the thin section of
the Rebun specimens, however, seemto the writers quite similar to those of
P. iu·alensis. The Iauer was describedby ivl. EGU<.:III (1951) from the Hiraiga
sandstone of Miyako. which is, according to S. SHIMIZU (1931 ), Aptian in age.
Genus Polyphy/loseris ranges from Upper
Jurassic to Cretaceous. T\vo individuals
of Placocoenia are at hand. Their stateof preservation is not very good. Thisis a Cretaceous genus.
Lithocodium was established G. F. ELLIOT in 1956 on specimens obtained fromthe lower Cretaceous of Iraq. R. El\IJO(1961) added two new species from theTorinosu limestone of Soma, Fukushima
Prefecture and of Kochi district.
judging from the above mentioned
palaeontological and stratigraphical data.
the geologic age of the Uennai upper
formation may be considered to be ofLower Cretaceous. Barremian or slightly
younger.

Notes on Specimens fromN alwtom betsu-mach i,
Eshashi County,
Kitami Province
Three specimens are at hand: one
small piece of coenosteum from Garo of
the Peichan I< iver (Pl. 41. figs. 1, 2 and
3) and two fragmental sections (Pl. 41,
figs. 5 and 6) from a railroad cutting at
about 1 kilometer to the west of Shotom-

27()

lYatarn HASlliMOTO (l1/d S11tekaz11 NAG1l0

betsu station.
\"11 hen he described the problems on
the stratigraphy of the Esashi Mountains, the senior writer (1960a) reported
the discovery of those fossils.
The Garo limestone runs nearly N-S
and upright within a thick pyroclastic
formation with pillow lavas; gray incolor. apparently barren of fossils excepting for only one which is identicalwith Spongiomorpha asiatica (Reg. No.
30416). R. ENoo (1960) described f'ye~zo­
poridium /obatum collected by S. hiA:\ISHI from a limestone lense exposed at
the Nakanokawa valley, a tributary of
the Pcichan River. This limestone isconsidered by the present writers to
be of nearly the same horizon as theGaro limestone.
The Shotombetsu specimens were foundin a thin section (Reg. No. 30409) together with Yezoaclinia sholombe/suensis(\V. H.\SIIE\IOTO, 1960b). They probably
belong to the genus Spongiomorplza.
hoKever. further study is impossible
due to failure to make sections of different orientation.
The geologic age of the formations
intercalating above mentioned limestone
is assumed to be Upper Jurassic according chiefly to the lithic character, though
there is little palaeontological evidence(W. IIASIII~IOTO. 1960b; R. ENDO, 1960).

Description of Spongiomorphoid

Order SPONGIO~IORPHIDA.
ALLOITEAL'. 1952
Family SPONGIOl\IORPHIDAE.
Fi<ECH. 1890
Genus Stromatomorplza, FRECH, 1890
Type of Genus Spongiomm·pha
sly/ifera FRECH

Stromatomorpha rebunensis HASHI:>.IOTO
and NAGAO. n. sp.
PI. 39, figs. 1-6: PI. 40. fig. 1.
1962.

Stromatomorpha yokoyamai.
:vlnTo and NAGAO, p. 235.

HASHJ-

Coenosteum massive. subsphaerical ;diameter of the holotype attains 5x7x
5 em; mode of attachment probably encrusting according to para type; consistsof ramified skeleton as if of sponge at
a glance at the well weathered surfaceof holotype ; however, it is not skeletal
elements. but skeletal interspaces fullup with silicate derived from rockmatrices enclosing the fossil which areimportant. After careful examination,
it is observed, that the coenosteum consists of two kinds of skeletal elements---------

Explanation of Plate 39
Figs. 1-5. Slromalomorpha rebunensis, n. sp. (Reg. No. 30Hl).
Fig. I. Cross section. x 3
Fig. 2. Vertical section. x3.
Fig. 3. Panial enlargement of fig. 2. x 8.
Fig. 4. Partial enlargement of r1g. 1. x8.
Fig. 5. Partial enlargement of fig. 5. x20.
Fig. 6. Stromatomorplw rebunensis, n. sp. (Reg. No. 30414).

HASHIMOTO and NAGAO:

Plate 39

Spongiomorphoids

3

4

5

2

6

S. AOKI ph oto.

47.'i.

Sp:muiomo1·ph'Yids from the C1·etaceous Sy.~tem of Hok!Pido

arranged vertical and in concentric order.
Vertical elements relatively more prominent than the concentric or horizontal
ones; short. very thin walled. slightly
sinuated trabeculae. thickned ring-wisely
with somewhat regular intervals; arranged nearly parallel and perpendicular
to the base or encrusting surface. Diameter of trabeculae ca. 0.1 mm. commonlyand 0.23 mm at maximum at the thickened part; thickness of thin wall ofskeleton about 0.03 mm.
Therefore. vertical elements appear in
the cross sect ion as rounded or somewhat irregular shaped figures of various
diameter up to 0.23 mm: often neighbouring ones connected at their thickened
parts or by short horizontal elements
show constricted lamellar skeleton as if
a short, sinuated rosario in the crosssection. In the vertical section. however.
they appear as slightly sinuated andgently waved moniliform. short 1rabeculae in parallel direction: sometimes.
neighbouring ones united with each otherat their thickened part or by short horizontal bars. therefore they show a wide
skeletal element with slightly constricted outline corresponding to longitudinal
low of a few or several small rounded{)r narrow longitudinally elongated pores-occuring at the central part of the widevertical element. Very thin, streight orslightly curved partitions occur at various levels within the vertical skeletal
elements; some of them are traceable
horizontally one by one in the verticalsection of vertical elements. for a considerable distance. This evidence probably means the older upper surface of
coenosteum.
Partition inten·al varies
from 0.175 to 0.21 mm commonly. attains{).-!6 mm or more not seldem.
Horizontal elements rather short, connecting neighbouring vertical clements

277

as short bars, therefore, they display
their cut ends and tangential figures inthe vertical section of coenosteum asrounded or sub-rounded spots with thinwall or horizontal bars of short ladderwith different lengthened side flame consisting of vertical elements ; sometimes,
a horizontal bar connects to the neighbouring vertical element with or without
interruption by the neighbouring one according to the grade of development of
the two elements. A horizontal element.
however. does not continue very far
horizontally, being limited within thespace including three or four verticalelements even in the largest specimen.
In the coenosteum cross section, horizontal elements appear as short, moniriform bars connecting cut ends of vertical elements. or form a moniriform ringwhich in turn, sometimes concentrates
in a small area to form lamellae withseveral rounded pores.
No partilion
occurs between horizontal elements.
Horizontal and vertical interspaces arenearly the same in width. Vertical elements counted 10-12 in 2 mm and horizontal ones 10-1-1 in the same distance.
:'\licrostructure of skeleton is fibrous
excepting for the expanded part ofskeleton where thin fibrous wall enclosing the transparent part consistedof carbonate crystal without any sharpboundary line.
No tabulae or dissepiment is observedin the interspaces of skeletons. Stellate
structure. none observed w·hich matched
typical one.
Remarks :-S/romatomorplw yolwyamai
YABE and SUGIY A~!A is a closely resembling species so the writers misidentified
the present species as a dwarf variationof the former. However, the present
species is distinguishable from theformer by its less development andH'ataru HASI!!MOTO and Sutekazu NAGA.O

278

short intervals of horizontal elements,
though their interspaces are narrower;no tabulae and fincss of skeleton as awhole.
Repository:-Tokyo Kyoiku Daigaku.
Reg. No. 30411. the holotype; No. 30413.
the paratype, No. 30414 and No. 30412.
Localities and Geologic Ilorizon:Locality No. R-11 of G. S. !IOI(., about
2 kilometers south of Uennai on thesouthern part of the west coast of
Rebun Island. Hokkaido. Uennai upper
formation: probably Barremian or slight·
ly younger in age.
Genus Spongiomorplw, FRECH. 1890
Type of Genus Spongiomorp//(/acyclina FRECH
Spongiomorpha asiatica Y ABEand SUGIYAJ\1A
Pl. 40, figs. 3. ·l and 5: Pl. II.
figs. 1, 2. 3 and 4.

1931. Spongiomorp!w
SuG 1y A:\IA. p.

1939.

asiatica. YAIIE and10·1. Pl. 34, ftgs 1-8 andPl. 35. fig. 6.
? Microsolena ? sp .. YABE andY.-\MA. p. 87, figs. l-3.

SuGI·

A few fragmental pieces of coeno·
steum conspecific with this species areat hand from Rebun Island and one
specimen from Garo of the Peichan
River, Nakatombetsu-machi, Esashi-gun,

Kitami Province. The largest one ofthem. from Loc. No. R-11 of Rebun
island is about 4 em long, 2x 1 em indiameter at one end and about 0.5 em
at the other end. This is probably apart of a cylindrical body, attached toanother organism. Bryozoa ? judging
from its weathered surface (Reg. No.
30,116). Another specimen shows lamellar nature in its vertical section as if it
was an encrusting form. i\lode of at·tachment of the Garo specimen is notknown.
Coenosteum is composed of verticaland horizontal elements. Both are nearly the same in diameter, about 0.05 mm.
Vertical one prominent. trabecullar in its
form. arranged almost in parallel withregular interspaces of about 0.12-0.14
mm. Horizontal elements connect theneighbouring vertical elements with re·gular intervals. about 0.1 mm or little
larger. Connecting pal'ts of both elements slightly increase in diameter towards the connecting point according as
they approach each other, form fourridges with low and round tops aroundhorizontal base and trabeculae and showroundness to the every corner of thelattice \Vork. form a round or elongatedpore by an arrangement of two eachhorizontal and vertical elements. Thus
the lattice structure with elongate roundspace appears in the thin sections. According to the orientation of the thinsection, there appear trabeculae furnish-

Explanation of Plate 40
Fig. 1. Stromatomorp!w rebune1zsis, n. sp. (Reg. No. 30413). x8.
Fig. 2. Polyphylloseris ? sp. cf. P. iwatensis EGUCIII (Reg. No. 30420). Cross section.
Figs. 3. 4 and 5. Spongiomorp!w asiatica Y ..un: and SuGJYA!\JA. (Reg. No. 30416).
Fig. 3. Vertical section. Partial enlargement of fig. 5. x8.
Fig ..f. Cross section. Partial enlargement of fig. 5. x8.
Fig. 5. x3.

x8.

H ASHIMOTO and NAGAO.·

Plate 40Spongiomorphoids

1

4

2

3

S. AoKI photo.

475.

Spouyicmor}llwids from the Cl·etaceous System of Hokka·ido

ed with rhomboidal expanding parts
having a regular interval or rhomboidal
or rounded cut ends in a row.
Stellate astroheather-like structure oc·
curs here and there. but not so often:
cross section of it shows such a structure that one vertical trabeculae incenter and 12 lamellae radiate from 6
points surrounding the central one inhexagonal arrangement (Pl. '10, figs. ·1
and 5. Pl. 41. figs. 1. 2 ~nd 3).
Remarks:- Although l'o/yphylloseris
has some similar characters, the present
specimens arc distinguishable from itby the characteristic stellate structure.
One of the Rebun specimens of Po/yphyl/oseris (Reg. No. 30420) is illustrated
for comparison (Pl. 110, fig. 2). Sample
shown in Pl. '10. figs. 3. -1 and 5 closely
resembles the figure of Microsolena ?
sp. illustrated by YABE and StiCIYA:>.tA.
in both skeletal structure and size.
Repository:- Tokyo Kyoiku Daigaku.
Reg. No. 30"116. the Rebun specimen:
Reg. No. 30410. the Garo specimen.

Heferences
AKtBA. C. and 0\IORI. T. (1959): Discovery
and its l\Ieaning of Crioceras from the
Rebun Island. jour. Ceo/. Soc japan.
XLV. (771). 789.
EGUCHI, ?vi. (19·18): A New S/romatomorphafrom the Orbitolina Sandstone of !walePrefecture and Its Significance in japan.
jour. Pa/eo111 .. XXII. (3). 365-367.
- - (19511: 1\Iesozoic Hcxacorals fromjapan. Sci. Rep. Tohoku Uni1•. 2nd.
Ser. (Ceo/.). XXIV.
ELLioT, G. F. (1956): Further Records ofFossil Calcareous Algae from the !'.Iiddle East. Micropaleolllology. I. (4). 327334.
EN Do. R. (1960):

Discovery of Pycnopori·dium lobatum from the Jurassic Torinosu Limestone Strata exposed in Kita·
minokuni. Ilokkaido. Sci. Rep. Saitama

27£1

Unit• .. Ser. B. Ill. (3). 271-272.
- - (1961): Calcareous Algae from theJurassic Torino~;u Limestone of japan.
Ibid .. Commem .. Vol. R. Endo, 53-57.
Geological Survery of Ilokkaido (1957): Geological Map of Ilokkaido, 1: 200.000.
Sheet No. 2.
HASHIMOTO, V{. (195Ba): Geology of Hokkaido.
Explanatory Text of the Geologic Map of Ilokkaido. 1:200.000.
- - (1958b): Considerations of the Geological History of the Yezo-Saghalien
Geosynclinal Area. Commem. Pub/. Prof.
Fujimoto's 60th /Jirthday. 101-111.
(1959): Geology of Hokkaido. Pt. III.
Underground Resources, (3). 13-20.
- - (1960a): Some Problems Concerning
the Older Deposits prior to the Middle
Yezo Group of Ilokkaido. Sci. Rep.
Tohoku Unir .. 2nd. Ser. (Ceo/.). Special
Vol. (4). <137-447.
- - (1960b): ·yezoactinia. A New Hydrozoan Fossil from Shotombetsu, ~aka­
tombctsu-machi. Esashi-gun. Hokkaido(Yezo). Japan. Sci. Rep. Toltyo Kyoiku
Dail(aktt. Ser. C. (60).
- - ( 1960c): Stromatoporoids from the
Ainonai Limestone. Kitami Pro,·ince.
Hokkaido Ibid .. Sa. C. (65). 195-203.
- - and NAGAO. S. (1962):
A Find ofSpongiomorphoids from the Basement
Complex of Rebun Island. Hokkaido.
jour. Geol. Soc. japan. LXVIII. (799).
235-236.
HASIII~IOTo. W. and TEt~AOKA, Y. (1962 MS.):
Mesozoic Fossils from the Nikoro Area,
Kitami Province. Hokkaido.
Htl.L. D. and WELLS, I. W. (1956): Hydroid
and Spongiomorphida. MooR's Treatiseon Invertebrate Paleontology. (F) Coelenterata. 81-89.
llokkaido Exploitation Committee (1951):
Geological Map of IIokkaido. 1 : 600.000.
MATSC\IOTO, T. (1942--13): Fundamentals
in the Cretaceous Stratigraphy of japan.
Pts. I-III. Mem. Fac. Sci .. 1\yuslm Imp.
Unit• .. Ser. D. I. 129-280: II. 97-237.
Nagano-ken Chigaku-kai (1958): Explanatory Text to the Geological Map ofNagano Prefecture. 1:200,000.

lVata1·u HASHIMOTO and Sutckazn NA'JLlO

280

Nn1oTo, T .. SA:-JBO:XSUGI, M. and MIZUGU·CHI. B. (1942):
Explanatory Text to
tbe Geological 1\fap of llokkaido in
1: 100.000. Xoborikawa Sheet.
OISHI, S. (1940): The Mesozoic Floras ofJapan. jour. Fac. Sci .. 1/okkaido Imp.
Unit• .. Ser. TV. V. (2-'1), 123··'180.
SATO, F. (1936 MS.): Geology and Petrologyof the Rcbun island. Graduation Thesisof the /nsf. Geol. and Min., Hokkaido
Unit•., (40).
SHI~uzu, S. (1931):
The Marine Lower
Cretaceous Deposits of Japan. with
Special Reference to the Ammonites·
bearing Zones. Sci. RejJ. Toholw Imp.
Unit•., 2nd. Ser. (Geol.), XV, (1), 1-40.
YABE, H. and SuGIYA:>tA, T. (1931): On
Some Spongiomorphoid Corals from thejurassic of Japan.
Ibid.. 2nd. Ser.
(Geol.). XIV. (2-A). 103-105.
- - (1935): Jurassic Stromatoporoids from
Ja1>an. Ibid., 2nd. Ser. (Geol.), XIV,
(2-B).

- - (1939a): Fosails from the Kamuikotan
System. jour. Geol. Soc. japan. XLVI,(5,19), :~40-341.
- - (l939b): Discovery of a Mesozoic
1-lexacoral in a "Green Schistose Rockof the Kamuikotan System" of Hokkai·do. Proc. Imp. Acad., Tokyo, XV, (3),81-89.
- - (1941):
Discovery of Cirocoporella
semic/atflrala HAYAS.\1\A from Hokkaido. .four. Geol. Soc. japan, XLVIII.
(568), 38-42.

P. S. Explanatory Text and Geological Sheet l\Iap" Rebun Island·· by S. NAGAO, C. AKtllA
and T. O~IORt was published in 1963 prior to contribution of this manuscript.

Anamaiwa
Garo
I wachishi
Jizoiwa
Nakanokawa

7 ·)- 7'-fi'}ipf~:· ~ ;!~lll! ~ '5
1Jl / Ill:'-lakatom betsu-machi
Peichan River
Rebun island
Shotom betsu
Uennair+l it j_JIJIIIJ~1;11~)11:fL3(.11J,1, ~m '-'ll~~I~

Explanation of Plale ellFigs. 1, 2, 3 and 4. Spongiomorpha asiatica Y ABE and SuGIYAMA. x 10. (Reg. Xo. 30416).
Loc. Garo of the Peichan River, 1\akatombetsu-machi, Esashi-gun, Kitami.
Fig. l. Litltocodium-bearing specimen.
Figs. 5 and li. Spongiomorplza Sl>· x 10. (Reg. No. 30•109). Loc. About I kilometer west to
I he Shotombetsu station, Nakatombetsu-machi, Esashi-gun, Kitami.

HASHIMOTO and NAGAO:

Plate 41

Spongiomorphoids

3

S. AoKI photo.

2

4

5

6

Trans. Proc. Palacont. Soc. Japan. N. S., No. 55, pp. 281-293, pis. 42, <13, Sept. 20, 1964

·176.

NATICID GASTROPODS FROroi THE ~IIYAZAKI GROUP(PALAEO~TOLOGICALSTUDY OF TilE MIYAZAKI GROUP-X)
TSUGlO SHUTO

Department of Geology, Faculty of Science, Kyushu UniYersity·::·;PiilJ~llHf. !I-~ ;r 1 :M: ·f.nJ,If~ilf~·rut.:t1J~j;j>:!WJ~Q)1iJf·fl:CD-i$ t L -c ll!Vt.fiill NaticidaenQ) -t ~· 9ft. ; t) 2 fiJ!Itifrfifi. Q)Jc·t&:a--t;,;,, i t.:.t;Y:*Q)ft'tffli.:.flf:::; -. ~·.Q)wt1i!lftQ)5tM:.:.-:>l'-c. l'.,,i1!jtJ:~7.JQ)<::..:C.tu.:.-:>~·-ct~-l\!.~M!"7.>,-fi· ~ ~ !fJ

Here are the descriptions of nine species of Naticidae from several horizonsof the i\Iiyazaki group. Of nine species
six are known in our country. two are
new to science. and one is possibly new
species.
l am greatly indebted to Professor
Tatsuro :VIATSUMOTO of Kyushu Uni·
versity for his kind suggestions andadvices during the field survey andlaboratory work. I wish to express mycordial thanks to Professor Ryuzo ToRIYAJ\IA of the same university for his
valuable advices and thorough criticismson the subject at the type script.
I also appreciate Drs. Tadashige HABE
of National Science Museum of Tokyoand 1\alura Qy AMA of the Geological
Survey of japan for their valuable ad·vices and discussions at the field of themolluscan taxonomy. This study waspartly financed by the aid of the science
research expenditure fund by the 1\linistry of Education.

Superfamily Naticacea
Family Naticidae
Subfamily Polinicinae
Genus Polinices Mo:'\TfORT. 1810
(type-species: Polinices a/bus MONTFORT=Nerita mamilla LINi\E byoriginal designation)
Subgenus Neuerila RISSO. 1926
(typc·species: Neverila Josephina
RISSO by monotypy)Polinices (Neverita) sagamiensis PILSBI{YPl. -!2, Figs. 2. 8 and 14.

190-1.

1922.

Polinices sagamiensis PtLSORY, Proc.
tlcad. Nat. Sci. Phi/ad .. Vol. 56. p. 23,
pl. 4, fs. 37, 37a.
Polinices pou·isianus, YoKOYA~IA. jour.
Coli. Sci., Imp. Uniz•. Tokyo, Vol . .J.J,
Art. 1, p. 83, pl. 14, f. 12 (nol of
HECIXZ).

1935.

Polinices sagamiensis. On;J<A, Bull.
Earthq. Res. Ins/., Vol. 13, p. 866, pl.
53. f. 26.
1951. Polinices sagamie11sis, (HI RASE) T.-\1\1,
1/a ndb. !/lust. Shells, pl. 91. f. 8.

Systematic Description
Received June 20, 196·1; read Jan. 19, 1961
at Fukuoka.

281

Tsugio SHUTO

282

Polinices (Mammillaria) sa.qamiensis.
TAKI
and OYA~Ic\. Palaeont. Soc.
japan. Spec. Pap., No. 2. p. 17. pl. 21.
f. 12.
195·1. Polinices saaamiensis, KIR.\. Colored
Il/ust. Shells japan, I. p. 35. pl. 17. f.
1954.

15.

1961.

Polinices sagamiensis. HAYASAKA. Sci.
Rep .. Toltoku Univ .. 2nd Ser .. Vol. 33,
no. 1. p. 75. pl. 9. fs. 12a, 12b.

Material :-GK-L 7987 (loc. Nihonmatsu). 7988-7990 (loc. Toriyama). All the
specimens \\·ere collected by myself.

Afeasurements :specimen
GK-L

max D

min D
(mm)

H
(mm'>

Hjmax D

numb.

(mm)

(%)

whorls

7987
7989

20.0
40.6

24.9
33.9

ca. 23.0

115.07~). 9

5.4
6.0

32.3

Remarks:- The specimens from Tori·yama are quite identical to the living
species, but that from Nihonmatsuslightly differs from others in being
provided with an obsoletely anrl shal·
lowly grooved band close to the upper
suture. This band starts at the one·
third of the third whorl. It is minutely
and spirally striated and bordered below
by rather a distinct step-like ridge. The
early two and one-third whorls are
separated from the succeeding whorl by
oblique and weak ridge which is more
distinct than the normal growth-lines.
This character is not observed on ordi·
nary specimens of P. sagamie11.~is. bothliving and fossil. and suggestsa possible
specific discrepancy between this andothers. I am, however. inclined to treat
this specimen as an abnormal varietyof P. sagamiensis. because subsutural
grooved band is examined only at asingle specimen.
The present species, although it has
been described by many authors as
Polinices MONTFORT, 1810. is quite
similar to the type species of :Ve!.'erila
RISSO, 1826. in general characters. espe·
cially in the outline and umbilicalfeature. Polinices mamilla (LINNE). thetype species of Polinices, has tall shellwith almost filled umbilicus. while

toe.

Nihonmatsu
Toriyama

Neverita Josephina Risso, the type-species of NeFerita. has depressed shellwith crescent umbilical furrow. The
difference in the outline of the shells
between these two type-species is very
distinct in reality. but they are reasonably congeneric on the basis of theseveral intermediate species.
Horizon:- The fifth and sixth fossil
horizon of the 1v1iyazaki group (Lower
Pliocene).
Localities :-1) Road side small cutting at Nihonmatsu, Takanabe machi.
Koyu gun ; 2) Railroad cutting at theentrance of a gorge near T6riyama,
1\awaminami machi. Koyu gun. !vliyazaki Prefecture.

Subgenus Glossaulax PILSBRY. 1929
(type-species: Natica 1·eclusiana
DESIIAYES by original
designation)
Polinices (Glossaulax) hyugensis n. sp.
Pl. 42. Figs. 3, 5. 13 and 15:
Pl. 43, Figs. 9. 10 and 12,
Text-figs. 1 and 2.

Material :-Holotype: GK-L 8009 (loc.
Hagenoshita. coli. T. SHUTO); paratypes:
GK-L 8001. 8002. 8008 (loc. Hagenoshita.

47ti.

Naticid Gastropods ji·mn the Miya.zaki Gronp

coil. T. NIATSUMOTO et al.). 8010 (loc.
Hagenoshita. coli. T. SJIUTO). 8005. 8006
(loc. Nihonmatsu. coil. T. SIIUTO). 80ll
(loc. Kugino. coil. T. SHUTO). 8012 (loc.

Nakabyu. coli. T. SIWTO), and 8035 to
80-10 (loc. Yamaji. coli. T. SllllTo). ~1anyother specimens from Toriyama are imperfectly preserved and not registered.

k!easuremenls :specimen
GK-L

max D
(mm)

min D
(mmJ

II
(mm)

H/max D

8002
8005
8008
8009
8010
8012

15. 1
14.8
15.8
20. 7
15.5
18.0

11.8
11. 7
13.5
17.5
12.9
14 6

12.4
11.7
13.8
17. 7
12.6
13.9

82 1
79.0
87.4
85.5
81.3
77.2

(%)

number ofwhorls

LA

LP

5.25
5.0(2.5)*

1?.9
128
124
129
131
134

142
140
133
144
139
1-H

5.5

5.3
5. 1
5.25(2.5)•(degrees)• Kumber of the proto·:onch whorls

Fig. l. Umbilical region of (1) Polinices (Giossaulax) hagenoshilensis n. sp.
(GK- L 800,1) and (2) P. (G.) hvugensis
n. sp.
The umbilicus is bordered by rather
the sharp edge and devoid of the inner
spiral furrow in both species. While they
are quite distingui:;hable each other inthe feature of the callus.

Diag11osis :-The shell is moderate insize. obliquely hemispherical. smooth,and rather solid. The spire is very
low. small. and depressed-conical. The
body whorl is large. hemispherical. \·erygently sloped below the suture showing
an extraconical profile with the pleuralangle larger than the apical one. The
suture is slightly depressed. The surfaceof the shell is ornamented by the closelines of gro\vth which are distinct below
the suture and at the base. The baseis oblique, roundly convexed. and deeply
umbilicate. The umbilicus is narrowed
by a distinct umbilical cord and partly
covered by the strong parietal callus.
The parietal callus extends backwarct
at its lower part along the edge of theumbilical furrow and is fused with theumbilical cord but bordered by a shallow groove between them. The umbili·
cal furrow is separated from the basal
surface by rather a sharp ridge. which
terminates at the anterior extremity of
the aperture. There is no spiral innerfurrow on the wall of the umbilicalfurrow, although many spiral striae areobseryed. The aperture is semicircularwith narro\vly rounded anterior end.
The inner lip is almost straight andslightly oblique. The outer lip is simple, sharp. slightly sinuate. and antecurrently oblique. The whorls are about
five of which early two and a half volu·
tions are perfectly smooth and shining
protoconch (text-fig. 2\. The protoconch
consists of more convexed volutions
sep:uated by deeper suture than in theconch whorls and bordered by more orless distinct groove between the firstconch-whorl.

284

Tsngio SHUTO

Fig. 2. Protoconch and early tdeo·
conch of Poliniccs (Glossau/ax) hyugensis
n. sp.

Comparison:- The present species isclosely allied to P (G.) vesica/is (PHILIPPI)
in general characters. but is distinguished from the latter in having the distinct
ridge separating the basal surface andthe umbilical furrow. white umbilicalcallus. and more triangularly pointed
lowest part of the parietal callus along
the ridge of the furrow. Furthermore
the anteriorly elongated columella ofthe present species gives a wider appearance to the aperture than in P.
z•esicalis.
The present species also closely resembles P. (G.) didvma (IWDil\G). flourishing in Japanese waters. in general. but

the former shows some critical differences from the latter. That is to say.
the former is (1) much smaller than thelatter : (2) the present species has notinner spiral furrow inside the umbilicalfurrow. which is evidently observed on
the adolescent and younger specimensof the latter.
Horizon.- The first. second. (third).
fourth. and fifth fossil horizons of thel\Iiyazaki group (l'vliddle :l\liocene toLo\vest Pliocene).
Localities :-1) Small cutting along thenational highway No. 10 at I-Iagenoshita.
Uwaye mura: 2) small cutting along thenational highway No. 10 at Nihonmatsu.
Takanabe machi; 3) road side small
cliff north of Yamaji. !vlino mura. Koyu
gun: 4) river shore at Nakabyu, Yatsushiro mura; 5) 300m south of Kugino.
Aya machi: Higashi-morogata gun. Nli·yazaki Prefecture.
Polinices (Glossaulax)
hagenoshitensis n. sp.
Pl. 42, Fig. 10. Text-fig. 1.

Material :-1-Iolotype: GK-L 8003, paratypes: GK-L 7993. 800-t and 8007.

,\1easurements :GK-L

max D
(mm)

minD
(mm)

8003
8004

14. 1
12.3

11.4
10.6

specimenH(mm)
ca. 11. 6
10.4

Diagnosis:- The shell is moderate insize. oblique, hemispherical. round.
smooth. and solid. The spire is small.
very low. and depressed-conical. The
body whorl is large. occupying morethan 90 percent of the total height ofthe shell, and very gently sloped justbelow the suture with slightly concave
part. The suture is impressed and dis-H;max D

(%)
82. 2
84.5

numb. whorls(N) (PN)

LA

LP(degrees)

2.5

2.4

127

139

2.6

2.3

135

142

tinct. The surface of the shell is ornamented with dense growth-lines. which
are distinct below the suture and at thebase and subobsolete at the periphery.
The protoconch is much smoother andmore roundly convex between sutures
than the conch and consists of morethan two and a half volutions. of which
the first is a minute dome and the476.

Naticid Gastropods from the Miya.za.ki Gmup

others are minute and round tube. The
end of the protoconch is marked by arecurrently oblique line. The umbilicus
is separated by moderately sharp edge
from the basal surface of the bodywhorl and narrowed by a large umbilical cord. which is provided with thelarger callus at the outer end than cord
itself. The parietal callus is thick andmoderately wide and somewhat extends
backward at its lower part along theedge of the umbilical furrow. It is.
however. not pointed as is seen in thepreceeding species beyond the limit of
the umbilical callus. but slightly narrower than the umbilical callus. Thereis a shallow groove on the surface between the parietal and the umbilicalcallus almost perpendicular to the columellar lip.
Comparison:- The present new species
is quite similar in size and outline of
the shell to the precceding species. but
differs in the features of the protoconch
and the umbilicus. I examined thespecimens in hand to check whether
the characteristics in question are mere
fluctuating variation or distinct features.
The result shows that these two species
are sharply separated and there is nointermediate form concerning with thementioned characteristics.
Horizon:- The fourth fossil horizon ofth~ l\liyazaki group (Lowest Pliocene).

285

Locality :-Cutting along the national
highway No. 10 at Hagenoshita. Uwaye
mura. Koyu gun. l\liyazaki Prefecture.
Poli uices (Glossa ulax) a ff.
reiniaua (DU:'\KEU)
Pl. 42, Fig. 1. Text-fig. 3.

1877.
1882.

1886.
1920.

195-1.

1958.

1961.

1961.

Nez•erila reiniana. DC:"KEI~. Malak.
Bliitt .. Vol .. 24, p. 71.
Ne1•erila reiniana. DUNI{ER. Index
Moll. Mar. japon. p. 62. pl. 4. fs. 15.
16.
Natica reiniana. TRYO:". Man. Conch.,Vol. 8. p. 35, pl. 13. f. 12.
Polinices (Ne1•erita) amp/a. YoKOYA·~lA, jour. Col/. Sci .. Imp. Uni1•. Tokyo.
Vol. 39. !lrl. 6. p. 77. pl. 5. f. 6.
Polinices (Glossaulax) rei11icwa var ..
TAKI
and OY.\MA. Palaeo111. Soc.
japan Spec. Pap .. Xo. 2. p. li, pl. 6,
f. 6.
N1werila reiniana. OzAKI. !Jull. Nat.
Sci. MilS. (Tokyo). Vol. 4 . .ll.'o. 1, p.
1-13. 2 text-fs.
Net•erila (G/ossaulax) rei11iana, H,\BE,
Colored Illusl. Shells Japan, II. p. 38.
pl. 17, f. 11.
Nez·erila (Glossaulax) reiniana, HAYA·
SAKA. Sci. Rep. Tolzoku U11i1'., 2nd Ser.
Vol. 33, No. 1. p. 76, pl. 9, fs. 18a,
18b.

Material :-GK-L 7991 and 7992 (coiL
T. SHUTO).

Afeasuremenls :specimen
GK-L

max D
(mm)

min D
(mm)

H
(mm)

H/max D(%)

numb.
whorls

7991
7992

24.6
ca. 19.5

20.5
15.9

ca. 22.5
ca. 16.3

91
83

ca. 5. 5
5. 1

Remarks:- The present specimens areprovided with a groove separating theparietal and the umbilical callus andreadily identified to Glossau/ax. Amongthe species of Glossaulax it closely:resembles P. (G.) reiuiana (DUNKER) withrather tall spire. roundly convexed
whorls. and solid test.
It. however.

~86

Tsuyio SHUTO

slightly differs from the living specimens of the species in having larger
umbilical cord and callus and in being
devoid of the spiral groove inside theumbilical furrow (text-fig. 3).

Uwaye mura, Koyu gun, Miyazaki Prefecture.
Genus Mammilla SCIIUMACIIEI~. 1817
(type-species: Mammilla fasciata
SCHUi\·IACHER=Neri/a melanosloma
G~IELINby monotypy):Hammilla meianostoma (G:-.rELIN)
Pl. 42. Figs. 4 and 6.
Nerita melanostoma. G~mLIK, Syslema
naturae. ed. 13. p. 367-1.
1852. Natica me/anostoma, PlllLIPPI (inMARTI~I-Ciml\I;o-;ITz) Conch. Cab .. Vol.
2. Nalica. p. 30. pl. 4. fs. 5, 6. 15. 16.
1956. Nalica melanostoma, REE\'E, Conch.
leon .. Fol. 9, Nalica, pl. 18. sp. 78.
1886. Natica melanostoma, TRYO;>.;, Man.
Conch .. Vol. 8. p. 50. pl. 21, fs. 13. 14;
pl. 22. f. 21.
1925. Natica(Mammilla)melanostoma,
Coss~tA::\N,
Essais de Paleoconch.
Camp., Yo/. 13, p. 129. pl. 1, fs. 36.
37: pl. 2, fs. 3. 4.
193-1. Polinices(Polinices)melanostoma,
LADD. Bernice P. Bishop Mus., Bull.
No. 119, p. 211.
(Polinices)melanosloma,
1935. Polinices
NmwRA. Sci. Rep., Tolwku Imp. Univ ..
2nd Ser .. Vol. 18. No. 2. p. 203, pl. 9,
f. 32.
19·11. Polinices (Mammilla) melanostoma.
ALTE;o-;.~. Leidse Geol. Meded .. Vol. 12.
p. 67.
1951. Polynices opacus. (lltRASE) TAKI,
Handb. 11/ust. Shells. pl. 91. f. I.
195-1. Polinices opacus, KIRA, Colored !1/ust.
Sllrlls japan. I. p. 35. pl. 17. f. 13.
1960. Mammillamelanostoma, MAcNEIL.
U.S. Ceo/. Sun· .. Prof. Pap., No. 339.
p. 54, pl. 8, f. 1 : pl. 12. f. 19.
1791.

Fig. 3. Umbilical region of (1) Poli·
nices (Giossaulax) reiniana (DuKKER)(recent) and (2) P. (G.) aff. reiniana(Dt.:;o-;KER) (GK-L 8992).
Note the similar callus and different
umbilicus. Recent specimens has the distinct inner furrow within the umbilicus.

The characteristics of the umbilicalregion of these specimens closely resemble those of P. hyugen sis n. sp ..
although their spires are generally moreelevated and the tests are much heayier
than the latter. There are three possibilities concerning with the taxonomic
position of these specimens. They may
represent a varietal group in P. reiniana:
they may be a stout form in P. hyugensis; or they may be a off-shoot of P.
hyugensis and the ancestor of P. reiniana.
Considering that the ele\'ation of thespire is rather variable and the speci·
men GK-L 7992 is hardly distinguishedfrom P. hyugensis in its outline though
the test is much more solid. I perfer tothe second possibility.
Horizon:- The fourth fossil horizonof the i\liyazaki group (Lowest Pliocene).
Locality: -Small cutting along thenational highway :"io. 10 at Hagenoshita.

Material :-GK-L 8033 (coli. T. SHUTOJ.

47U.

Naticid Gostropods j1·om the Miyazaki Group~87

1\feasurements :specimen
GK-L

max D
(mm)

H
(mm)

H;rnax D

numb.

lllllll)(%)

whorls

8033

9. 1

:i.9

10 8

118

4.5

min D

Remarks:- The present ;\Iammi/Ia
specimen is featured by depressedly
pear-shaped tall outline, slit-like very
narrow umbilicus. and almost smoothsurface except for minute growth lines
and safely identified to M. melanostoma{GNIELI:-<). Its shell is slightly taller
and its umbilicus is much narrower
than those of M. maura BRUGUli~RE.
which is a close ally to it. J/. lw rodai
TAKI (=:Vaiica macros/oma PI!ILII'l'l in
i\IARTINI and CHEl\INITZ. 1852. p. 55, pl.
9. f. 1. T AKI. 1943. p. 111. text-fs. I. 2)
is closely allied to the present species.
but the former has wider umbilicus.
stronger growth-lines. and somewhat
wider shell than the latter.
Comparing with AI. simiae (Dt-:SIIA YES)
(18..!2. p. 652). living in south Japan. thepresent specimen has much heavier
callus.
!Iori zon :-The second fossi 1 horizon of
the i'vliyazaki group (i\liddle Ivliocene).
Locality :-Road side cutting north of
Yamaji. ~vlino mura. 1\.oyu gun. Miya-zaki Prefecture.
Mammi/a maura (I3RUGUJERE)
Pl. 42, Figs. 7 and 9.

1792.

;\'alica maura, BJWGUJERE, Encyclopedie methodique pl. 453, fs. 4a. b.
1852. Natica maura. PliJLIPPI (in M.\RTII'J·CJJET\JNJTz). Conch. Cab .. Vol. 2, Nalica,
p. 58, pl. 9, f. 6
1856. Nalica maura, REEVE, Conc/i. Icon.,Vol. 9. 1\lalica, pl. 7. f. 25.
1886. Nalica maura, THY0:'-1. Man. Conch.,Vol. 8, p. 51. pl. 22, f. 24.
1951. Polinices maurus, (HJRASE) TAKI,
Ha ndb. I/ lust. Shells. pl. 91. f. 3.
195cl. i'olinices (Mammilla) maurus, KlllA,
Colored lllust. Shells japan, I, p. 35,
pl. 17. f. 12.

.\lall!rial: -GK-L 803:1 (loc. Yamaji,\11-5070. coli. T. SHUTO) and 8045 (Joe.
Hagenoshita. coli. T. Sl!CTO).
The
specimen GK-L 80311 is slightly broken
at the labrum and 80,15 lost the apicalpart of the protoconch.

Measurements:specimen
GK-L

max D
tmm)

8034
80-15

5. •I
8.5

min D
( 111111)

13
5.8

Remarks:- The present specimens arefeatured by the broad shell. deep anddistinct umbilicus. moderately disrinct
growth-lines. and dark brown uniform col·oration. On the basis of these charac·
teristics they are identified to .\/. maura(BRUGUIERE), although the former ismuch smaller than the living specimens.

H(mm)

H;max D

7.2
9.8

133

(%)
115

numb.
whorls

•1. 0
5. 1

Horizon:- The second and fourth fossil
horizon of the ~liyazaki group (.Vliddle
Ivliocenc to Lowest Pliocene).
Localities :-Small cutting along thenational highway No. 10 at Hagenoshita. Uwaye mura; road side 600 m
north of Yamaji, ~vlino mura, Koyu-gun.
?-.liyazaki Prefecture.

288

7:'!ugio Sf!lJT'(J1921.

Genus Lunalia GRAY. 18-!7

f. 5.

(type-species: Natica ampularia

19,15.

SOWEJ<BY by original designation)

1960.

Lzmalia pa/lida BRODERIP and SOWERllY
Pl. ·13. Figs. 4. 6. 7. 8. 11 and 13.

1829.

1886.

? Euspi1·a pal/ida, DAt.L. U.S. Nat.
Mus., Bull., Vol. 112, p. 164, pl. H.

? Natica pal/ida. BRODERIP and SowERnY. Zoo/. jour .. Vol. 4. p. 372 (inDAI.I., 1921).
? Natica pal/ida, TRYOl'<, Man. Conch.,Vol. 8. p. :n. pl. H. fs. 26 to 28.

? Lunatia pal/ida. ABBOTT, American
Sea shells .. p. 190. f. •13c.
Euspira cf. pal/ida, MAcNEIL. U.S.
Ceo/. Sun•., Prof. Pap., l'io. 339, p. 57.
pl. 2. fs. 20, 26.

,"fa/erial :-GK-L 8018 to 8023, 8025.
8026. 8029 (loc. Nihonmatsu, coli. T.
SIWTO). 8013 to 8017. 8027. 8028 (loc.
Ilagenoshita. coil. T.l'viATSUl\tOTO et al.).
and 8032 (loc. Hagenoshita. coil. T.
Sll {)TO).

Afeasurements :specimen

max D

GK-L

(mm)

8013
8018
8025
8027
8028

7.8
9.5
12.5
12.6
14. 7

minD
(mm)

H
(mm)

6. 2

8. 1
10. 1
13.4
13.6
ca. 15. 7

7.6
10.6
10.6
12.9

Remarks :-The present thick-shelled
specimens are featured at first by mod·erately shouldered outline with the
maximum convexity at higher part of
the whorls. In other words the whorls
are narrowly rounded just below thehorizontal or gently sloped subsuturalpart (shoulder). Secondly the umbilicus
is moderately narrow but yery deep.
and not separated from the basal surface by a sharp angulation. The parietal
callus is thick, solid. wide. and partly
truncated at the margin of the umbili·
cus, where it merges partly to the narrower columellar callus. The eversion
is also thickly deposited with the callous
material. There is no funicle in theumbilicus. Thirdly the suture is impressed. On the basis of these charac·
teristics they are identified to •· ?Natica
pal/ida BI<ODERIP and SowERBY ".
They are very closely similar to

H/max D

numb.
whorls

101

4.0
4.25

(%)
106

107
108

107

ca. 4.8
5.0
5.0

AGASSIZ. 1838. and Lzwatia
1&17. I. however. consider they
are reasonably included in Lzmatia, because they have solid shell, being devoidof the shallow groove between theparietal and umbilical callus which are
the important characteristics of Euspira.
New Zealand genus. Uberel/a FINLAY.
1928, with the type-species. Natica
l'ilrea HuTTON. is also closely allied tothese genera, especially to Lzmatia andit seems there is no critical distinction
between them as far as the descriptions
and figures arc concerned.
" Uberella yokoyamai (KURODA andIIABE) ., (T AKI and 0YA~IA, 1954. p. 17.
pl. 5. f. 1), which is originally reported
as Gennaeosinum (?)(KURODA and HARE.
1952, p. 59), is distinguished from thepresent specimens in having the maxi·
mum convexity at lower position thanthe latter.
Although this difference

f:u spiraGJ~A Y.

476.

Na#cid Gastropods from. the Miyazaki. Group

looks very slight. it is markedly persistent to serve as the criterion forinterspecific separation.
The present specimens arc very
closely allied to" Nalica gendinganensis
MARTI:-\" (1899. p. 262, pl. 29. fs. 627,627a) in general feature. The only difference is that the latter has more produced anterior end of the aperture andeversion and somewhat smaller ratio ofthe diameter of the whorl to the diameter of the whorl-tube of the same
whorl. I prefer to deal with it as asubspecies of L. pallida.
Horizon:- The fourth and fifth fossil
horizon of the Miyazal\i group (Lower
Pliocene).
Localities :-1) Small cutting along thenational highway No. 10 at Hagenoshita. Uwaye mura; 2) cutting along
the national highway No. 10 at Nihonmatsu. Takanabe machi, Koyu gun,1vhyazaki Prefecture.

289

Pl. 42. Fig. 11; Pl. 43, Figs. 1. 2. 3 and 5.
Natica janthostoma. YoKoYA~IA. Jour.
Col/. Sci .. Imp. Unir•., Tokyo. Vol. 39,
Art. 6. p. 76, pl. 5, fs. 3 and 4 (notof DI'SIIAYES).
1934. Natica (Teclonatica) janthostoma. K!·:->OSHITA and lsAHAYA.
Rep. Fish.
Sun• .. Hokilaido Fish. Exj!erim. Stat ..
lllo. 33, p. 7. pl. 4, f. 27.
1935. Natica (Tectonatica) janthostoma. No~lt:R,\, Saito Ho-011
Kai Mus. Res.
Bull. No. 5. p. 122. pl. 7. fs. 4 to 6.
1935. Natica (Tectonatica) jantllostoma. No~tt:RA and HATAI. ibid., No. 6. p. 128.
pl. 9. f. 4.
1949. Tectonatica janthoslomoides. KcRoD.-\
and IL-\BE. Venus. Vol. 15, :\'os. 5-8,
p. 7. text-fs. la to d.
1954. Natica (Teclonali,·a) serera. KIRA,
Colored Jllust. Shells Japan. /, p. 35.
pl. 17. f. 18.
1858. 1\'atica janthostomoides, OZAKI. Bull.
."-rat. Sci. Mus .. (Tokyo). Vol. 4. No.1.
p. 14~. pl. 19. fs. I and 2.
1961. Tectorwtica janthostomoides. HAYA·
SAKA, Sci. Rep. Tohoku Unil' .. 2nd Ser.,
Vol. 33. No.1. p. 7i. pl. 9. fs. 20a and b.

1920.

Genus Tectmwtica SACCO. 1890
(type·species: Natica tectula Bo:>:ELLI
by monotypy)

Material :-GK-L 799,1 to 7996. coli. T.
MATSm10TO et al.. 7997 to 8000 and
8031, coli. T. SHUTO. All the specimens
came from a single locality.

Tectonatica janthostomoides

KURODA and IIABE
Measurements:H

specimen
GK-L

max D
(mm)

H/max D

(mm)

(%)

numb.
whorls

7995
79!)7
7998

16.8

16.8

100

14.9

103

5.5
5.2

110

15. ,,
II. 5

8031

12.2

12.9

The largest specimen. GK-L 7994.
attains about 20 mm in maximum diameter.
Remarks: -The present specimens
generally have much smaller shell \Vith

104
106

5.0
5.5

more closed umbilicus than the living
ones which are provided with narrow
but apparently open umbilical furrowaround the umbilical callus and cord.
Of course the degree of closure at the

'290

Tsu.gio SHUTO

umbilicus is not invariably fixed but
somewhat variable and some specimens.
as GK-L 7995. show typical umbilicusof T. jantlwstomoides.
The present
specimens may represent a group which
is biased but not so different from thetypical one as to be separated specifically.
Horizon:- The fourth fossil horizon ofthe ~vliyazaki group (Lowest Pliocene).
Locality:- Small cutting along thenational highway No. 10 at Hagenoshita. Uwaye mura, Koyu gun. i\!iyazaki Prefecture.

Tectonatica sp.
Text-fig. 4.

Material :-GK-L 8030. coil. T. SI!UTO.
Measurement :-II= 13.6 mm. number ofthe whorls=5.0.
Description:- The shell is moderately
small. moderately thick. and globose.
The spire is moderately elevated. The
whorls are about five in number. andround. The body whorl is large. roundly convex at the side slightly above themiddle. round at the base. and not umbilicate. The aperture is semicircular.
The outer lip is not observed becauseof fracturing. The labrum profile ismoderately oblique judging from thegrowth lines. The inner lip is moderately curved and covered by the distinct
callus. The parietal callus is wide.
thick. and perfectly fused with the umbilical one which entirely closes theumbilicus. The callus of the lower partof the columellar lip is also thick andcontinued to the produced eversion.
Remarks and comparison :-The glo-

Explanation of Plate 42
Fig. I. Polinices (Glossaulax) aff. reiniana (DUNKER)
GK-L 7991 (xl.6), loc. 1-lagcnoshita.
Figs. 2. 8. 1-1. P. (illel'erita) sagamiensis PILSBRY
2... GK-L 7987 (x2.2). loc. Nihonmatsu,
S ... GK-L 7988 (x1.3). loc. Toriyama,
IL.GK-L 7989 (x0.9). loc. Toriyama.
Figs. 3, 5, 13 and 15. P. (Glossaulax) hyuge11sis n. sp.
3 ... paratype: GK-L 8008 (x2.3). loc. Hagenoshita,
S... holotype: GK-L 8009 (x2). loc. Hagenoshita,
13 ... paratype: GK-L 8012 ( x2.3). loc. Nakabyu,
15 ... (x2.3). same specimen as fig. 13.
Figs. 4 and 6. Mammilla mela11ostoma (G:o-IELI:\1)
L.GK-L 8003 (x3), loc. Yamaji,
6 ... (x3). same specimen as fig. -t
Figs. 7 and 9. J'.J. maura (BRUGUIERE)
7 ... GK-L 8045 (x3). loc. Hagenoshita.
9 ... (x3). same specimen as fig. 7.
Fig. 10. Polinices (Glossaulax) llageuoshitensis n. sp.
paratype: GK-L 8004 (x2.5). loc. Hagenoshita.
Fig. ll. Teclolwtica janthostomoides Kt.:RODA and H.-\nE
GK-L 7998 (x3). loc. 1-lagenoshita.
Fig. 12. Lunatia pallida (BRODERIP and SowEIWY)
GK-L 8018 (x3). loc. Nihonmatsu.

SHUTO :Naticids from the Miyazaki Group

Plate 4'i

476.

Naticid Gastropods from. the .vliyazaki Group

bose shell with moderately elevatedspire and utterly closed umbilicus indicates that the specimen belongs to
Tectonalica. Although whole species ofTectonalica known in our country havethe umbilical callus fused with theparietal callus. their umbilical callus isapparently separated from the parietal
one by the remarkably contracted part
between them. \\hile in the present
specimen. they are perfectly fused together and not separated each other.
This peculiarity together with the occurrence of the specimen from thehigher horizon than the prececding
species supports the ide:t that the
specimen may not be included in therange of variation of T. janthoslomoides
and may be a new species. The establishment of the new species is, however,suspended until! plenty specimens are
examined.
Horizon:- The fourth fossi 1 horizon ofthe ~liyazaki group (Lowest Pliocene).
Locality :-Cutting along the national
highway No. 10 at 1\ihonmatsu. Takanabe machi, Koyu gun. !vtiyazaki Prefecture.
Concluding Remarks

Some revisions of the systematic position of certain common japanese naticid
gastropods are given in this report.
Polinices sagamiensis PILSBRY wasusually classified into Polinices s. s. by
Japanese authors. but the former isreadily distinguished from the !alter in
depressed shell and is better to be
included in Ne1•erita Risso. 1926.
Glossaulax is usually included in
Net>erila also by Japanese authors. but
the latter is devoid of the shallow
groove sep:Hating the parietal and theumbilical callus which is the typical291

feature of the former.
G/ossaulax
should be separated from Neverita.
.Vatica pa/lida BRODHIP and SOWERBY
is considered to be included in Lunatia
GHA Y, 18-17. on the basis of the shellcharacter. The species seems to be acharacteristic to the Lower Pliocene oflndo-southw·est Pacific region. That is
to say, besides in japan it also occurs
in the Lower Pliocene of Okinawa Islandand its close ally, L. gendinganensis
IMAtnil') (l90:J, p. 262J in the Lower
Pliocene Bantam bed of Java.
Works Cited
R T. (195·1): American Seashells.
pp. 1-541, pis. 1-40, Nostrand Co, NewYork.
AJ.-:-E:'\,\, C. 0. van Regteren (19·11): The
marine mollusca of the Kendeng beds
(East Java): Gastropoda, pt. 2. Leidse
Ceo/. Meded., 1/o/. 12. pp. 1-86.
HtWGUJERE, J. G. (1792): Encyclopedie methodique. Vol. 1, pt. 2, pp. 345-758.
Cossr-.tAN:-<. Maurice (1925): Essa is de paleo<'oncltologie comparee. Vol. 13, pp. 1-345,
pis. 1-ll.
DALL, Wilhelm II. (1921):
Summary of themarine shell-bearing mollusks of thenorthwest coast of America, from San
Diego. California, to the Polar Sea mostly contained in the collection of theUnited States National Museum, with
illustrations of hitherto unfigured spec:es. U.S. Nat. .\Jus. Bull., :Vo. 122. pp.
1-217. pis. 1-22.
DEsHA YES. G. P. (1842):
Histoire naturelle
des animaux sans vertebres. Vol. 8.
Du:'JKER. Wilhelm (1877):
Mollusca non·nulla nova maris japonici. Malak. Blii/1.,
Bd. 24. pp. 67-75.
- - (1882): Index molluscorum maris japonici. pp. 1-301, pis. 1-16, Kassel.
GMELJ:-<,]. F. (1788-1793): Systema naturae,ed. 13.
GRAY, l F. (184i): List of the genera ofrecent mollusca, their synonyma and
AUI30TT,

292

Tsuai.o SHUTO

types. Proc. Zoo/. Soc. London. pp. 129206.
IIABE, Tadashige (1961.): Colored illustrations of shells of Japan. II, pp. 1-183,
pis. 1-66 (in Japanese), Hoikus!Ja, Osaka.
IIAYASAKA, Shozo (1961): The geology andpaleontology of the Atsumi peninsula.
Aichi Prefecture, japan. Sci. Nep., Tohoku Unil' .. 2nd Ser .. Vol. 33, No. 1. pp.
1-103. pis. 1-12.
Kr:-:osHIL\, Toraichiro and lsAHA YA, Takao(1934): Catalogue of the mollusks of
IIokkaido. japan. Rej1. Fish. Sun>. Jfokkaido Fish. Experim. Stat., No. 3.1. pp.
1-19, pis. 1-15 (in japanese).
KrRA. Tetsuaki (1954): Colored illustrationsof shells of Japan. I. pp. 1-172. pis. 1-67.
(in japanese), /loilws/za, Osaka.
KuRODA. Tokubei and HABF., Tadashige(1949): On Natica janthostoma and anallied species which was confused with
it. Venus (Japan. jour. Malac.), Vol. 15.
,-...'o. 58. pp. 67-72 (in japanese).
- - and - - (1952): Check list and bibliography of the recent marine mollusca
of Japan, pp. 1-210, Tokyo.
LADD, H. S. (1934): Geology of Vitilevu,
Fuiji. Ben1ice P. BishoP Mus. Bull .. No.
119.

MAcNEil-. F. Stearns (1960): Tertiary and
Quaternary gastropoda of Okinawa. U.S.
Geol. Sum, Proj. Pap .. 1\io. 339, pp. 1-148.
pis. 1-19.
MARTI:-;, K. (1899): Die Fossilien von java:
Samml. Ceo/. Reichs Mus. Leiden. neue
Folge, Bd. 1, A/11. I. Heft 5-10, pp. 133332, pis. 21-45.
NoMURA, Sitihei (1935a): On some Tertiarymollusca from northeast Honshu. Japan.
pt. 2. Fossil mollusca from the vicinityof Ogino. Yama-gun, Hukusima Prefec·
ture. Saito Ho-on 1\ai Mus. Res. Bull.,
No. 5, pp. 101-130, pis. 5-i.
- - (1935b): Catalogue of the Tertiary
and Quaternary mollusca from the islandof Taiwan (Formosa) in the Instituteof Geology and Paleontology, Tohoku
Imperial University. Sendai. Japan. pr.
2, Scaphopoda and Gastropoda. Sci. Rep.
Tolloku Imp. Unit• .. 2nd Ser .. Vol. 18, No.
2. pp. 53-228, pis. 7-10.
- - and HATAI. Kotara (1935): Pliocene
mollusca from the !Jais}•aka shell-bedsin the vicinity of Daisyaka, Aomori-Ken
Northeast Honsyu, Japan. Saito Ho-on
Kai Mus. Res. /Ju/1., No. 6. pp. 8-142,
pis. 9-13.
OLDROYD. L S. (1927): The marine shells

Explanation of Plate 43
Figs. 1, 2. 3 and 5. Tectonatica janthostomoides KuRODA and HABEl ... GK-L 8031 (x3): loc. Hagenoshita,
2 ... GK-L 7997 ( x2.5). loc. Ilagenoshita,
3 ... ( x 3). same specimen as fig. 1,
5 ... GK-L 7998 (x3). loc. Hagenoshita.
Figs. 4, 6, 7, 8, 11 and 13. Lunatia pallida (BRODERIP and SowERBY)
L.GK-L 8027 (x3), loc. Hagenoshita.
6 ... GK-L 8026 (x3). loc. Nihonmatsu,
7 ... (X3). same specimen as fig. 6.
8 ... GK-K 8012 (x3), loc. Nihonmatsu,
1J...GK-L 8028 (x3), loc. Hagenoshila,
13 ... ( x 3). same speci :nen as Fig. 1 L
Figs. 9, 10 and 12. Polinices (G/ossaulax) hyugensis n. sp.
9 ... paratype: GK-L 8005 (x2.5). loc. Nihonmatsu,
10 ... (x2.5), same specimen as Fig. 9.
12 ... paratype: GK-L 8002 (x2). Joe. Hagenoshita.

SHUTO:

Naticids from the Miyazaki Group

Plate 43

476.

j\iat.icid Gastt·opods from the Jiiyazak1: Groupof the west coast of north America :Scaphopo<.la and Gastropoda. StanfordUnh•. Press .. Vol. 2, pt. 1. pp. 1-297, pls.

l-29. pt. 2, pp. 1-304, pb. :30-72, pt. 3,
pp. 1-339. pls. 7:3-108.
0Tt:KA, Yanosuke (1935): The Oti-grabcn
in southern Noto peninsula, Japan, pt. 3,
Bull. Earthq. Res. Ins/ .. Vol. 13, No. ·1,
pp. 846-909, pls. 5:3-57.
OzAKI, Hiroshi (1958): Stratigraphical andpaleontological studies on the Neogene
and Pleistocene formations of the Tyosi
district. Bull. Nat. Sci . .\Jus. (Tokyo).
No. -12. pp. 1-182. pls. l-24.
PIIILIPPI, R. A. (1849): Centuria tertia testaceorum noYorum. Zeitschr. f. Malak ..
f. 1848. fJd. 5. pp. 151-176, pp. 186 192:
Bd. 6. pp. 17-26, pp. 33-35.
- - (1852): Die Gattungen Natica und
1tmaura in l\·l.\RTI:'\1 and CIIEMto;ITZ,
Syslematische Conchylien-Cabinet, FJd. 2.
PJLSBRY, H. A. (190·1): New Japanese marine
mollusca: Gastropoda. P1·oc. :lead. Nat.
Sci. Phi/ad .. Vol. 56, pp. 3-:37. pls. 1-6.
- - (1929): Ne11erita reclusiana (DES II.\ YES)
and its alii~;. Nautilus. Vol. 45. pp. 109133, pl. 6.
- - and VANATTA, E. G. (1909): Notes on
Polinices didyma. with description of a
new Australian species. Proc. Acad.
1Vat. Sci. P/Jalad .. Vol. 60, pp. 555-559,
pl. 29.
REEVE, L.A. (1856):
Conchologia Iconi..:a,Aya machi
Hagenoshita
Higashi-morogato gun
Kawaminami rna<.: hi
Koyu gunKuginoMino mura

~

IUJ

xi1)r
JtWHi~l!l;

JIIHilllJ~lJ;.jf,j\.7.*!ltf:==:~t-~9, Natica, pis. 1-30.
RtiDI:-<G, P. F. (1798): Museum Boltenianumsive catalogus ci melionum e tribus
regnis naturae. Hamburg.
SAcco, F. (1890):
Molluschi dei terreni
terziari del Piedmonte e della Liguria.
Scuu:...tACHER, C.]. (1817): Essai d'un nouveau systeme de habitations des vers
testaces. pp. 1.. 287, pis. 1-22.
TAI<I, Isao (I-Ii RASE, Shintaro) (1951): Handbook of Illustrations of Shells. pp. 1-46.
pis. 1-134. /Jzmkyokaku, Tokyo.
- - and 0YA~IA. KaLura (195-l): The Pliocene and later faunas from the Kwanto
region in japan. Paleont. Soc. japan.
Spec. Pap .. No. 2. pp. l-68. pis. 1-49.
TAKI, lwao (1943):
The mollusca of theinland sea of Japan. pt. 2. japan. jour.

.\!alae .. Vol. 13, Nos. 1-·1, pp. 111-118.
LeXt-figs. 1-1-t.

Tnw;o,;, G. V•T. (1886): Manual of conchology, Vol. 8.
Wr.~z. W. (1943):
in 0. H. SCIII:'\DEWOLF.
Handbuch der Palaozoologie, Bd. 6,
Gastropoda (Prosobranchia), pp. 12011596.
YoKOYA:-oL\, Matajiro (1920): Fossils fromthe .l'vliura peninsula and ils immediate
north. jour. Coil. Sci., Imp. Unit'. Tokyo.
l~"o/. 39. Art. 6, pp. 1-193, pis. 1-20.
- - (1922): Fossils from the upper Musashino of Kazusa and Shimosa.
ibid ..
Vol. 4·1, Art. 1. pp. 1-200. pis. 1-17.

Nakabyu
Nihonmatsu
Takanabe machi
T6riyama
Uwayc mura
Yamaji
Yatsushiro mura~l 1 lJUif.f=-*tJ~·~mmrlill Jli..tiiH
Lll lf3i\(~ftTrans. Proc. Palaeont. Soc. Japan, N. S., No. 55, p. 294, Sept. 20. 1964

SHORT NOTE
12.

DISCOVERY OF CONODONTS AND HOROTHURIANSCLERITES IN JAPANKLAUS J. 11t.iLLER

University of Tokyo and Technische Universitiit. Berlin·Charlottenburg

1n connection \Vith demonstrations on
etching techniques at the University ofTokyo and various other universities I
had the opportunity Lo dissolve somelimestones of the Japanese Paleozoic andTriassic in l:l% acetic acid, in order toto find conodonts and other microfossils.
Well preserved and fairly abundantconodont faunas have been secured from :1) Lower Triassic limestone. Kamura
formation. Kamura: Takachihocho, i\liyazaki Prefecture. Kyushu.
(leg. KAl\IBE)
2) Lower Triassic limestone with
Anasi!Jirites. Taho formation. Taho;
Shirokawa-machi. Ehime Prefecture Shikoku. (leg. K. ICIIIKAWA).
Similar material was also etchedfrom the collection of the Tohoku
University.
The Taho formation also has yielded

excellently preserved early ontogenetic
stages of Ceratitina, with exposed thepro- and the primary sutures. and shallbe studied by Prof. SATO.
!Iolothurian sclerites have been secured from the Lower Carboniferous Omi
limestone. containing Procluctids. Locality: Omi. Niigata Prefecture (leg. T.
HAJ\IADA.l and from material of the University of Tokyo (Pal. 330. Omi-mura,
Echigol.
Furthermore. silicifications have been
observed at various places. e. g. in the
Permian limestones of Kuzuu. Tochigi
Prefecture.
The studies are not completed as yet.
and a more detailed account will be
published in the Transactions and Pro·
ceedings of the Palaeontological Societyof Japan.

• Received Sept. 28, 1962

2!).1

Article 19.

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CONSTITUTION
of the
PALAEONTOLOGiCAL SOCIETY OF JAPAN
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Honorary Members are persons of distinguished achievement in palaeontology.
They shall be recommended by the Council and approved by the General Meeting.
The members of the Society shall be obliged to pay the annual dues stated in
Article 12. Members shall enjoy the pri\"ilege of receiving the Society journaland participating in the activities stated under Article 3.
The rates for annual dues shall be decided by l he General Meeting. Rates forannual dues are: Regular Members. Yen 1.000: Fellows. Yen 1.500: and Foreign
1\lernbers, S ,1.00. Patrons are organizations donating more than Yen 10.000 annually;
Honorary !vlembers are free from ohligations.
The budget of the Society shall be from membership dues. donations and be·stowals.
The Society, by decision of the Council. may expel from membership persons
who have failed to pay the annual dues or those who han~ disgraced the Society.
The officers of the Society slwll be composed of one President and fifteen Coun·cillors. among whom several shall be Executive Councillors. The term of office
is two years and they may be eligible for re-election without limitation. The
President may appoint se\·eral persons who shall be Secretaries and Assistant
Secretaries. An Executive Council shall be nominated and approved by theCouncil. Councillors shall be elected from Fellows by vote of returned mailunsigned ballot
The President shall be a Fellow nominated and appro\·ed by the Council. The
President shall represent the Society and supen·ise the business affairs. The
President may appoint a Vice·President when he is unable to perform his duties.
The Society may have the honorary President. The honorary President shall berecommended by the council and approved by the General Meeting. The honorary President may participate in the Council.
The Society shall hold regularly one General l\leeting a year. The President
shall be Chairman and preside over l he administrative affairs. The program
for the General Meeting shall be decided by the Council. The President may
call a special meeting when he deems it necessary. The General Meeting re·quires the attendance of more than one·tenth of the members. The President