fJ -lt"'~±.~~~-~-~~tTransactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 17

Palaeontological Society of Japan
April 10, 1955

CONTENTS
TRANSACTIONS
258.

On the Occurrence of Aturia in Provinces of Etchu and Iwami andtheir Bearing on the Palaeoflumenology in the Miocene of Japan........................................ Teiichi KoBAYASHI and Kiyoshi MAsATANI

259.

1

Eumorplzotis multt'fonnis sldonosawensis, wbsp. nov. from the Shiono·
sawa Limestone at Shionosawa, North of the Sanchu Graben, Kwanto
Mountainland, Japan ..................... Koichiro lcmKAWA and Yukio YABE

260.

5

Discovery of Glyptophiceras from Hyogo Prefecture, Japan ................ ..
... ... ... ... ... ... ... ... ... ...... ... ... ... ... Keiji NAKAZAWA and Daikichiro SHIMizu 13

261. Non-marine Mullusca from the Paleogene Uchigo Group of the Joban
Coal-field, Japan ...................................................... Yasuhiko KAMADA 19
262.

Occurrence of a New Species of Pleuronectites in the Triassic of Japan................................................................................. Masahisa AMANo · 23

President:

Hisakatsu YARE

Councillors:

Kiyoshi AsANO, Riuji

E~oo(Business and Accountant), Seido

ENDO, Haruyoshi FuJIMOTo (Publication), Shoshiro HANZAWA, Ichiro
HAYASAI<A, Nobuo li<EBE, Teiichi KoBAYASHI (Editor), Jiro l\1AKIYAMA,
Tatsuro MATSUMoTo, Masao MINATo, Tokio SHIKAMA, Fuyuji T AKAI
(General Affairs), Hisakatsu YABE.

All Communications relating to this Journal should be addressed to the
PALAEONTOLOGICAL SOCIETY OF JAPAN
Geological Institute, Faculty of Science, University of Tokyo, Japan•

Trans. Proc. Palaeont. Soc. Japan, N.S. No. 17, pp. 1-4·, Pl. 1, Apr. 10, 1955.

258.

ON THE OCCURRENCES OF ATURIA IN PROVINCES OFETCHU AND IW AMI AND THEIR BEARING ON THE
PALAEOFLUMENOLOGY IN THE MIOCENE OF
JAPAN.*TEIICHI KOBAYASHI and KIYOSHI MASATANI

jlJjrfl, !fiJ\!.I:.~It .Q Aturia O)j!ff/H C. -t:-11:> H:;$:*ifi!f:ti/flj~$:J:i:::~lt.QAlJ:~ :-~"?"f:lE.ftii:'M
llH~.I:WfJIIlc.~*iN!IIfll~ll.i{±Jil·e.]€~ L..t-: Aturia (t!J';t;t.I:.J: .Q C. A. minoensis ·e-t-o:>i!t!t!!a-JJ.~ C.
.Zit+1l~o:>~~ o:>'"!!ifM1tfl't41J.I11:>IIII-"ifl}ffftfl!~-.: IJ ·Q~i~vt-: ~ L..l.·~l., ll?linWllilfl:lJ v :/ 7:iJ.~ !*!~~iL
t-: <!, O)·([iij~.!tl!l:. 2 /lblO) Nautilus O)!i:lf!t i.lil t-: P..:iJ• t> J! -r:, Z~O)~Ef1JO'f~O)i(l(tnl(><t%lmi'Jifl:. J:"?"f:tJifr$ • ~f.tnJHi:iJ, t>~b!f L.. -r: :!M-: i. 0).!.: :I!-" ~iL'!>o J."b#H~lli:EI:IO)f,lfjiil~!fll:.J?jJ!~tt.t-: Aturia
sp. indet. i..::: o:>~~~a-~a-t ~--WT~'-!-("<<h ~otJ';j;j;~- • iF.1~ iW

It was over 10 years ago that thejunior author hacl discovered a specimenof Aturia from the Miocene Yatsuo
series11 at Tsuzara, near Sasazu in
Etchu, Toyama Prefecture,2' as reported
already by him (1946). It belongs now
to the collection of the Geological Institute, Hiroshima University. Lately thisspecimen in addition to another nautiloid
from Iwami, Shimane Prefecture, weresent by htAMllRA to the senior author
for study. The former is identified herewith Aturia minoensis, recently describedby the senior author (1954). He visitedthen the locality with TsunA as a guideand confirmed its being a necroplanctonic float.
Before describing these specimens anddiscussing their palaeoftumenologicalbearing on the Proto- Tsreshima oceanic
curretlt, the authors wish to thank Prof.
Sotoji lMAMlii<A of the Hiroshima University and Mr. Karyn TsuDA, lecturerof the Niigata University.

Aturia milloensis KoRA y ASHI
Plate 1, Figures a·d.
1954. Aturia minoensis

KonA YASI!l, fa pan.
four. Geo/. Geogr. vol. 25, p. 35, pl. 5, figs.
a-d; text· fig. 1.

DescriPtion :-The Tsuzara specimen issmaller than the holotype from Hazama·
gahara of Togari, its maximum radius
being 41 mm. where the whorl is 18.5mm.
in breadth. In the same section th(!'* Read Oct. 9, 195.\; received Sept. 3, 1954.
1) The sequence of the Yatsuo Series
Otogawa ('tf}ll) Series
Joyama (.Milt) beds
Yatsuo(J\~)

SeriesKurosedani (W:i'ti11f) beds
Iwaine {!ftfgj) beds

Kashio (~) alternations of mudstone, sandstone
and conglomerate
Kakehata (;ff#JI() conglomerate, sandstone andmudstone( Kamikurose (J:.'.'.~illii) alternation of sandstone andmudstone

Nirehara (liJ:Irl.l{) beds
Jurassic Tetori Series and llida gneiss complex2) ~11.H~l:~JII1fiS*iR!I!flllJUI!;i±JII
1

2

Teiichi KoaA YASHI and Kiyoshi MASATANI

radius of the penultimate whorl is 15mm.
The siphuncle of the ultimate whorl islocated at a distance of about threefourths the length from its venter tothat of the penultimate whorl.
Both of these specimens arc middle
Miocene in age and agree with eachother in all of the observable characters,
namely in the mode of coiling, whorl section, septal distance and so forth. The
ventral saddle is subquadrate but witha shoulder on each side and the lateralside a little sigmoidal. Starting fromthe preceding shoulder, the septal suture
describes a large semi-circle on theflank which is more strongly convex on
the inner than on the outer side.
The conch is compra>sed laterallywith the result that the septa in the
inner volutions are seen to be broken
into pieces. A part of the outer shellremains on a flank of the last whorl,
but no surface marking is preserved.
For the comparison of this species
with its allies the reader is referred tothe senior author's paper (1954).
Occurrence :-Dogawa, Tsuzara, Osawano-town, Kami-shinkawa-gun, Toyama Prefecture; middle Miocene Kurosedani beds of the Yatsuo series.
The upper division of the Kurosedani
beds which is called Kashio, is marked
off from the upper Miocene Joyama
beds by a thin layer of sandy tuff. At
the cliff of Dogawa a few other layersof sandy tuff are intercalated in the
n1udstone beds. In addition there are
two wedges of conglomerate in thesequence, which contain pre-Tertiary
rocks, andesites and reworked angularmudstones. The upper wedge whence
the Atttria specimen was procured isabout 1.2 m. at the thickest and contains
many shells most of which arc however
broken. Pati11opecten kimurai, Chlamys

1tisataie11sis, Ve11en'cardia,

Glycymeris,

Sip!tonalia and Turritella yoshidai arecommon members. It is noteworthy that
TsuDA obtained two fragmentary shellsof Nautilus at this small wedge. While
the wedges of conglomerate are warm
shallow sea sediments, the mudstone
must be a much deeper and cooler bottom sediment not only because of its
fineness, homogenity and uniformity but
also because thin shelled Yoldia andPropaeamusseum are fo.~\fld scattered init.
Because intraformational folds arc
occasionally found in the mudstone beds
at other places, it is probable that theconglomerate wedges are shifted blocks
slipped down on the off-set plane of a
fossil delta.
The Kashio division is thus composedof mudstone, sandstone, conglomerateand sandy tuff and yields Operwlina
and lv!iogypsina beside them. The oceanographic situation at that time is presumed to be similar to that of the
Toyama bay at present in the respectthat the surface water was warm but
the deep one cool.
The middle division of the Kurosedani
beds called Kakehata consists of similaralternations.
According to OYAMA(1950), the Telescopitem-Geloina biocoenosis in it comprises about 40 species in
Littorionopsis (scabra group), Telescopium, R lzi'zopllorinwrex, Geloi11a and soforth. Noting that Batillaria, Coritlzidea,
Stenotlryra and G/aucome live in hypoha·line waters, the former two are foundonly in tidal zone, Natica, Tritia, Decoltfer, Es/elacar, Scapharca, ]oan11isie/la,Cyclina (s. str.) and Clementia (s. str.)
found in hypohaline waters and fromthe tidal zone down to deeper waters,
and Tatwiwaia, Vicarye/la and Vicarya
may be considered tidal zone dwellers,
etc., he emphasized the mangrove swamp
for the habitat of these Molluscans.

On the Occurrence> of Aturia in Provinces of Etchu and Iwami

Bunoloplzodon is known to occur in the
Kamikurosc alternation of sandstone andmudstone in the. lower part of theKurosedani beds and Liquidamber formosa HANCE and Compto1tipllyllum 1tattmmmi NATJJnRsT in this and middle
divisions. Thes~ plants indicate wannland climate.
Returning to the cephalopods, thecoexistence of two Nautili and one
Aturia, all fragmentary, in a small
wedge of conglomerate is a remarkablefact because Aturia and Nautilus areboth rare genera in the 1\iiocene ofJapan. As mentioned above, it is recognizable that a warm current was flowing
along the coast of this region in the
middle Miocene epoch. It is known further that living Nautilus happens tocome ashore.
Its usual habitat is,however, at the bottom in a deep water.
Furthermore, if considered that gregario•,Js occurrence of the rare fossils(KoBA YASJJJ, 1954), these Nautiloids must
be necroplanctonic floats.
Prof. Shozo MoNJI of the BotanicalInstitute, University of Tokyo kindly informed the senior author of the factthat the northern limit of mangroveswamps may be Okinawa of the Ryukyu
islands where is a natural forest of
Bruguiera JJYnmorrltiza LAM. at Yagagishima, Bane-village, Kunigami-gun,3>
although its occurrence is reported from
Atumi-Oshima. A few bushes of Katzdelia Rlzecdii WRIGHT ct AR:-o. at Kinyu
village, Ibusuki-gun1 1 and Kaseda village,
Kawabe-gun,s> both in Prov. Satsuma,
Kagoshima Prefecture, Southern Kyushu,
are said in traditions to have been imported from the Ryukyus in 1614:~)
4)

£icfJ;ll4iiJi~J11'l·JtillMI3U.l<:tll!!i'Jlll!!llJ:!i 1!i~lWfi'Hlil'ftA.N

5)
6)lll!!Ji-t.,I.':/ 1JI~}IIill1!!11JU lll:lllM::kmHIIMJ:J!H;tnW~JJii~.'lll!ltl]lrf;fHI;Ift<l!'f-~'lf{3(NAKANo, 1920). Assuming the northerly
shifting of isotherm for some 10 degrees
of latitude in the middle Miocene epoch
which is suggested by the 1'e/escopiumGeloina biocoenosis, Nautilus would havebeen able to thrive near Formosa as
does in the central Philippines.
Miocene was the time of a great submergence for Japan. As discussed elsewhere (KoBAYASIII, 1941). there wasalready the Proto-] apa11 sea. The distribution of Vicarya, ;\fiogypsi1la-Operculi11a and other fossils warrants that
there was the Proto- Tsuslzima curre11t
on the continental side of the insulararc. Therefore it is highly probablethat Atttria minoensis in question as
well as indeterminable Nautili associatedwith it in the same conglomerate wedge
have flown by the current from thesouth or possibly from off Formosa or
Yaeyama islands of the l~yukyus andfound a place to settle in this region.

Attwia sp. indct.
Plate I, Figures e·f

This specimen was obtained from the
Miocene Togane formation at Senjojiki
of Toganc, near Hamada, Province Iwami,
Shimane Prefecture. From the other
Molluscans 0TUKA (1937) concluded that
the Togane formation is contemporaneous with the Lower Kadonosawa Series
in Province Mutsu, North Japan, but
noted that the fauna of the former isdifferent from that of the latter in thelack of any cold water element. The
Lower Kadonosawa series is the Kadonosawa proper the age of which is middle Miocene (HANZAWA, 1934).
The chambered shell with a siphuncle
belongs undoubtedly to a nautiloid. As
seen in the magnified figure, septa arc
prolonged into long funnels from their

4

Teiichi KoBAYASHI and Kiyoshi MAsATANI

necks. They are each invaginated into
the preceding funnel almost as long as
the septal distance. There is a narrow
space between any two funnels, butwhether or not there was a connecting
ring in this place (Mir.LER and FURNISH,
1938) cannot be answered with thisweathered specimen.
As it has a holochoanoidal siphuncle,
it belongs evidently to Attwia which is
the only Miocene survivor among the
Het·coglossa-Aturia group (MILLER, 1949)
and a sole genus of the kind so far
known from the Tertiary of Japan. Its
septal distance is as short as that of
Atzwia miuoe11sis with which it is nearlycoeval. In this state of preservation,
however, it is extremely difficult tomake an exact specific identification.
Though fragmentary, it is worth
while to describe not only because of
its new find in this area, but also
because it vindicates the above suggested
course of the Proto· Tsushima current.
References
FLOWER, H.R. and B. KUMMEL, jr. (1950), A
Classification of the Nautiloidea. Jour. Pal.,
Vol. 24.
HANZAWA. S. (1954). Tohoku l~egion. Regional
Geology of Japan. Asakura Book Co.
lKEHE, N. (1949), Tertiary Stratigraphy ofWestern Toyama and Eastern Ishikawa
Prefectures, 1. Science of the Earth, Vol.
J, No.1.
KonAYASIII, T. (1941). The Sakawa Orogenic
Cycle and its Bearing on the Origin of theJapanese Islands. four. Fac. Sci. Imp. Univ.
Tokyo, Sec. 2, Vol. 5, Pt. 7.
- - (1950). Chugoku Region. Regional Geologyof Japan. Asakura Book Co.
- - (1954), Izumonauta, a new Genus of the
Argonautinae, with a Note on their rare
but gregarious fossil Occurrence. Japan.
Jour. Geol. Geogr., Vol. 25.
- - (1954). A Contribution toward Palaeo·
Flumenology, Science of the Oceanic Cur·rent in the Past, with a Description of a
new Miocene Aturia from Central Japan.
JaPan. Jour. Ceo/. Geogr., Vol. 25, Nos.
1-2.

MASA'rANJ, K. (1946), On Aturia discoveredin the Yatsuo Series. Hokokudan·shi ofToyama College, No. 4.
MAI<IYAMA, ]. (1950), Chubu Region. Regional
Geology of Japan. Asakura Book Co.
i\!II.LER, A.K. (1949), The last Surge of the
Nautiloid Cephalopods. Et•olution, Vol. 3.
- - and W.l\1. FURNISH (1938), Aturias
from the Tertiary of Mexico. Jour. Pal.,
Vol. 12.
NAKANO, H. (1920), On Ramuda Pond and
Ryukyu-Kogai Locality. Survey Reoprt on
Nature Conservation. Report on HistoricallVorks and Natural Monuments, No. 8.
- - (1920). On the Plants in Okinawa Prefec·
ture. Ibid. No. 21.
OTUKA, Y. (1937), On the Tertiary Formationof Hamada. Jo~~r. Geol. Soc. Tokyo, Vol.
4-1.

OYAMA, K. (1950\ Studies of Fossil Molluscan
Biocoenosis. No. 1. Bioecological Studies
on the Mangrove Swamps with Descrip·tion of New Species from the Yatuo
Group. Geo/. Surv. Japan, Rep. No. 132.

Explanation of Plate 1
Figures 1-'l. Aturia minoensis KoRAYASIIl from the middle Miocene Kurosedani beds of the Yatsuo
S~Cries at Dogawa. Tsuzara, Osawano·town, l{ami·shinkawa·gun, Toyama Prefecture, (Province
Etchu). One and a half times magnified.
Figure 5. Aturia sp. indet. from the Miocene Togane formation at Senjojiki of Togane near
Hamad:~, Shimane Prefecture (Province Iwami). Twice magnified.
These two specimens are kept in the Geological Institute, Hiroshima University.

KoBAYASHI

and MASATANI: Two Aturia from Etchu and Iwami

PLATE 1

3
5

Trans. Proc. Palaeont. Soc. Japan. N.S., No. 17, pp. 5-12, Pl. 2. 1 text-fig., Apr. 10, 1955.

259. EUMORPHOTIS MULTIFORMIS SHIONOSAWENSJS,SUBSP. NOV. FROM THE SHIONOSAWA LIMESTONE AT
SHIONOSA W A, NORTH OF THE SANCHU GRABEN,KWANTO MOUNTAINLAND, JAPAN.*
KOICHIRO ICHIKAWA and YDKIO YABE
Division of Geoscience, Institute of Polytechnics, Osaka City University andGeological and Mineralogical Institute. Faculty of Science. Tokyo University of Education.

~ J;(!lJf1l!llJ1Ittl!!ifli1.1}~t1JO):!i.\~Eb'(-!fii!lf Etmwrpholis multiformis shiouosnweusis, nov.

1.: .-,~'-c : 'f!'~r.·u)- A ?:ffi\1.:. J:jLtf. ~;;c.O)Jt!!~l.:.lttJ.imii..H:iJl1(:'ri~frtrTll'IH·'"''"* (:-\ ·!lk1) n:7}1!i L-c~ '~n:. · · ~L l•dl>{-1r(11.:. ;!;, ?J:!i.\iR~JX~ J: IJ. :llhci!Mll~~:t 1- lJ 7 :7,fi!J5"iti:O)

E. mu/liformis var.

<.

~O)llff~H ~t$ t:-c1., ~o lffl~!Ku c.*.W·I~ c. O)J1!!1'J:OOf~Ht7Filfl!ii·('~ ~n:. c.1.:.n,.:£"0) ci=.~imlli
1t.:fllt. 1E L ( E. mul!i/ormis ·C?j;, IJ. i-O)t#iffifl!l.:.~-t'7.:> 0 Wff:J~~T-tJ.":?J,U£(1)~:;j>:~~:f:J Lt.:lmi:llt

Eumorpholis T!tO)t'HH·:!\Jltl·l.:. -t ~.l:l.:.*j;l] t.dlf';,jHt_::\:'}.l} t.: O)·c, :::.. ::.1.:.. .:£"(1) ;~"t*Jnf,t: .~~~llll~~1';:,oiliJli!;li-nl; • ?:;'lJIZ.~J

In 1947, JWAI reported the occurrenceof Aviculoperlell sp. and Naticopsis sp.
from a limestone lens within the
Permo-Carboniferous Chichibu complex
distributed l'o the north of the Sanchu
graben.
The limestone is located at the entrance of the Kamakakezawa (of Shionosawa, Ueno-mura, Tano-gun, Gumma
Pref.) about 500m north of the northernfault of the Sanchu graben.
Subsequently, SIIIKAMA (1952) expressed theopinion that the limestone is early
Triassic in age, yielding Eremorplwtis
multi/ormis BITTNER var., A1lodmztop!tora
canalellsis CAT., Oxytoma sp., N aticopsis?
sp. and an indeterminable gastropod.
He then proposed provisionally the name
Shionosawa for the formation including
the mentioned limestone. The formation,
however, seems not to be distinctly
defined against the surrounding Chichibu
complex. (See postscript II)

During his general survey of the central part of the Sanchu gr,tben, thejunior author made a rich collection offossils from the above-mentioned locality.
According to him, the area around the
locality is mainly occupied by HlC Lower
Permian Odaira formation which ismostly composed of green or purple
tuffs, tuffaceous rocks and cherts wilh asubordinate amount of clastic rocks.
At a point (Loc. 2 in the index map)
about 1700m east of Shionosawa he discovered a limestone lensc within thisformation, yielding Parafusulilla /ormtani Du:-oaAR et SKINNER, Sclzwageri11a
japmzica GiiMnEL, Acervoschwagerina sp.,
Codonofusiella? sp., and some minor
foraminifera .I>
There are two kinds of limestone atShionosawa, i.e., the main impure limestone member and the fossiliferous
1) For the identification of fusulinids, theauthors are indebted to Mr. MoRIKAWAof the Saitama University.

* Read Oct. 9, 1954. received Oct. 5. 1954
5

6

Koichiro lcliiKAWA and Yukio YABE

f
Locality l\Iap
Loc. 1 Shionosawa limestone
Loc. 2 Odaira limestone
limestone member, the latter of which
is no more than 2m thick. The name,
Shionosawa limestone, is here used forthe latter member. The Shionosawa
limestone thus defined is interpreted to
be an exotic block shut in the Lower
Permian Odaira formation by a kind of
fault, although there remain somedoubts as to its field occurrence.
Because the Triassic formation has
not been known to the north of theSanchu graben in the Kwanto mountainland, the age determination of the
dubious block ought to be very prudent.
With the insufficient materials it issometimes difficult to distinguish thelate Palaeozoic aviculopectinids from theTriassic eumorphotids.
As the result of their careful works
on the extensive collection, however, thepresent authors could ascertain that themain member of the Shionosawa fossilcoenesis is a new subspecies of Eremorphotis multi/ormis (BITTNER).
The present paper deals only withthe description of this new subspecies ofEumorphotis multiformis. Detailed comments on the geology of the environs
and the description of the remaining
species will be given by the juniorauthor in another opportunity.
Thanks are due to Dr. K. NAKAZAWA
of the University of Kyoto for theopportunity of examining Emnorphotis
from Kyoto Prefecture, which he has
recently described.
As a graduate
student of the Tokyo University of
Education the junior author here records
his indebtness to Prof. H. FUJIMOTO andProf. K. HATAI of the same University.
Further, he wishes to thank Mr. ].
ARAI of the Chichibu National Museum
for the support given to him during his
survey.

Description of Species
Genus Emnorphotis BITTNER, 1901
]ahrb. Geol. Reichsmrst. 50, p. 566

Genotype: Pseudomonotis telleri BITTNER,
1898 (designated by DIENER, 1923, p. 40)

Remark :-Generic character of Ett·morphoti"s and its distinction from theother allied genera will be given in theforthcoming paper by the senior author.

Eumorphtis multiformis (BITTNER)
slziotwsawensis lcmKAWA et YABE,
subsp. nov.
Plate 2, Figures 1-15

l'v!aterials: There are more than ahundred fine specimens of the left valve
and several tens of the right valve at
hand.
Description: Shell thin, medium sized
for the genus, the left valve being commonly 30 to 35 mm high (rarely 44 mmhigh), a little higher than long, lengthby height being 1.04-1.18, a little inequiJateral, only slightly prosocline in theadult, and becoming a little elongatedpostero-ventrally. The left valve convex

Eumorphotis multiformis slzionosawtmsis, subsp. nov. from Shionosawa

and the right only slightly convex.
Left valve longitudinally ovate inoutline, regularly and well inflated, themaximum convexity lying at about
dorsal two-fifths of the height and the
maximum length at about the midheight. Dorsal margin almost straight,
about six-sevenths as long as the shelllength, the anterior side being about
three-fourths of the posterior; anterior
and posterior margins broadly arcuate,
turning gradually into the well roundedventral margin. Both wings not distinctly differentiated from the shellbody, the anterior one smaller than theposterior and a little convex, its anterior
margin forming the angle of about 60°
with the dorsal margin in the adultspecimen, curving inward as it descends,
and finally ending in the weak concavity
at the junction with the anterior marginof the shell body, the boundary line between the wing and the shell body isweakly sulcated in the interior, but not
so on the external appearance, hence
the part is thickened ; posterior wingprojected posteriorly, but never exceeding beyond the posterior extremity, its
postero-ventral margin forming a concave arc and gradually grading into theposterior margin of the shell body.
Umbo located at the anterior two-fifthsof the shell length, only slightly prosogyrated, narrow, but well convex, rising
a little above the hinge-line, curving inward and ending in the pointed summit
at the dorsal margin. Surface of theshell body and the anterior wing covered with the radial ribs of the 1st, 2nd,
(and rarely 3rd) orders and the finerradial striae. The ribs increasing in
number by insertion and comparatively
fine, but the differentiation into orders
is distinct at least on the mesial part,those of the 1st and the 2nd orders
alternating each other and rarely inter-

7

calating that of the 3rd order. The
first kind of ribs appearing already inthe early stage, 0.5 mm high, the second
from the umbonal part, about 3.5 to
5mm in height and the third from thestill later stage. The interspaces between the neighbouring each two of ribs
wide and covered with very fine andclose-set radial striae, which count 6-9
in the mesial part and are not entirely
uniform in strength and some of whichbecome nearly as strong as the ribs of
the 2nd or the 3rd order in the laterstage of growth. The concentric element of the sculpture is lacking except
for the very fine and close-set growth
striae which in later stage of growthform lattices with the fine radial justmentioned. The posterior wing is marked only with the comparatively distinct
fine radial striae and the growth striae.
Ligament area is very narrow and provided with very fine close-set horizontal
striae, the dorsal and ventral margin of
the area nearly parallel-sided in themain part, the ligament groove behindthe umbo is quite shallow and oblique
like that of the modern Pinctada martensii DuNKER, but not as wide as thelatter.
Right valve slightly convex
throughout the shell body, the maximum
inflation lying at about the mid-heightor slightly higher.
Dorsal margin
straight, its anterior side being about
three-fourths of the posterior side. The
outline similar to that of the countervalve except for the antero-dorsal margin and the wing part. Antero-dorsal
margin oblique and nearly straight, but
only slightly concave near the beak
Posterior wing small, less protruded andmore shallowly sinuated below than thatof the counter valve, its posterior margin forming the angle of about 70°-80°(rarely 45°) with the dorsal margin.
Anterior byssal car semicircular in out-

Koichiro ICHII\AWA and Yukio YABE

8line, separated from the shell body by avery narrow and deeply incised serration.
Surface of the shell body and the posterior wing covered with fine numerous.
close.sct radial striae of two or rarely
three orders. The stronger striae are alittle more crowded and more numerous
than the radial ribs on the countervalve, the weaker striae inserted between each two of them arc less in

number than those on the other valve.
Concentric fine growth striae are especially distinct on the posteriur wing.
Observation : The shell is quite thin
except for the boundary part of theanterior wing and the shell body in theleft valve, where it is comparatively
thick. Accordingly, the muscular impressions are hardly discernible in spiteof the favorable state of preservation.

Measurement in mm.
Left valve
Specimen
No.

Reg. no
-

( 1)
( 2)
( 3)
*( 4)
( 5)

-

5401 Holotypc

5411

( 6)

( 7)
( 9)
(10)

ocu 251

(11)

(13)
*(14)
(15)

5413

(!())

54{)8
5410

(51)
(52)
(53)

5412
54..o7

(62)

(63)
(&l)

(65)
(90)

LengthHeight

-44.0
31.5
33.5
39.0
4t. 0
34.5
29.0

:n.o
20.0
33.0
34.0
29.5
2:{. 0I
2•t. o( +)34. 7( +)
37.0
25.0
34.5
24.4
24.0
26.5
34. 5( +)22. 2( +)30. 0( +)30.5
34.0(+
27.5
38. 7( +27.0( +

I

(54)

(56)
(57)
*(58)
(59)
(60)
(61)

- -

5409

1

38.5
29.0
31.0
34.5
39.5
29.0
25.0
26.5
18.:1
30.0
32. 7
25.0
19.5
21. 5
33.5
21. 0( +)
22.1
29. 7
22.8
22.3
26.5
3iJ.. 0( +)23. 0( +)2•t. 5( +)26.0
25.0( +)
24.0
35. 7
27.5

Height/Length

Thickness

1. 14

11. 5
9.0
10.0
11.0

1. 08
1.08
1. 11
1.18
1. 16
1.17
1.11
1.10
1.04

1.18

1.13
1.16
1. 05
1. 08

1. 18
1. 14

11.5
8.0
8.5
8.0
7.9
6.5
11.0
7.5
7.0
7.0
11.0
11.5
10.0
11.3
9.0
9.5
8.5
9.0
10.5
8.0
8.0
10.0
7.0
10.7
8.0

Eumorpholis multi/ormis shi01wsawe11sis, subsp. nov. from Shionosawa

9

Right valve
(31)

(32)

5402 Paratype
5•105

(33)
(34)

•(35)
(36)
*(37)
(40)
(41)
(38)

5406

23.5
25.0
24.5
24.0
Z:t 0

2.0

2<1. 5( +)

28.0
24.5
17.0
23.0
26.5
24.6
29.3
21. ·i22.1
26.5
19. 0( +)
22.2

2.5
2.0
2.0
4.0
2.5
2.5

5
19.5
26.0
28. O( +)
27.0
31.5
22.4
23.5
28.0
24.2
23.2

2~.

ocu 252

(71)

(74)
(76)
(78)
(79)
(80)
(81)

26.5
25.0( +)
I
27.0
25.0
23.0

540~

1. 13
1.10
1. 04

1.13
1. 13
1.10

1. 08
1. 05
1. 06
1. 06

4.5
3.0
2.5
2.0

4.5

2.5
3.5

3.0
3.0

1. 05

2.3

* Deformed specimen
Although we have no bivalved specimen, the right valve must be smaller
than the left valve judging from thegeneral size of the both valves as enu.
merated in the table. The different
sizes of the dorsal margins of the both
valves suggest that they are not completely matched with each other evenalong the hinge-line.
The angle between the dorsal and theanterior margins of the anterior wingof the left valve is about 60° in the fullgrown specimen, but is smaller in theyounger stage.
The fact that there is no bivalved
specimens among the hundreds of verythin and yet well preserved specimens
suggests that the ligament of this species
is easily liable to damagement.
Comparisott and remarlls : The present form is quite similar to E. mul#formis from the Lower Triassic depositof Ussuriland (BITTNER, 1899, p. 10, pl.
2, figs. 15-22) in the height-length pro-portion, inclination of the shell, modesof the umbo and the wing parts, andthe general convexity of the valve, butthere are a few slight but innegligible
differences between them. In the firstplace, the Ussuri form is slightly taller
than the Shionosawa form, h/1 being
1.11±7 in the latter and 1.17±6 in theformer. In the second place, the posi·tion of the line of the maximum length
in the left valve is slightly higher in
the Shionosawa form than in the Ussuri
one. Thus the ventral half of the shell
outline appears rather slender in ourform. In the third place, there seems tobe slight difference in the mode of radial
sculpture in the left valve. BITTNER(1899, op. cit.) describes that the left
valve of E. multiformis bears the radial
elements of different orders arranged inaccordance with such a formula as
1434243H or 133313231, etc., although
the formula is, in practice, more orless disordered. Fine radial striae in10

Koichiro lclllKAWA and Yukio YABE

our form, which approximately correspond to the ribs of 3rd and 4th ordersin BITTNim's description, count 6-9
within the interspace between the stronger ribs in the mesial part and areevidently more numerous than those in
the Ussuri forms, so far as BITTNER's
description is concerned.
When theJapanese form is compared with BITTNER's illustration, however, this difference appears not so evident. In wellpreserved specimens from Shionosawa
the total number of radial ribs and thefine striae counts 15-16 within thebreadth of 5mrn at the distance of 20mm
from the beak, which number is similar
to that given in BITTNER's description.
Indeed, the mode of manifestation of
the complex radial elements are very
hard, and this third difference must be
checked, in future, by the comparisonof actual specimens from the two districts. Lastly, it is pointed that theright valves of E. 1mtltiformis illustratedby BITTNER arc, if correctly identified,evidently longer than high, while thoseof the Japanese form are higher thanlong. Considering the above-mentioned
respects, the authors think it desirable
to separate the Shionsawa form from E.
lmtltiformis of the Ussuri district as a
new subspecies.
The dorsal margin of the left valveof slzionosawensis is shorter than its
shell·lcngth, whereas RITTNER remarks" ihr Schlossrand ist lang, kaum kiirzer
als die Breite (Lange) der Klappe ".
This remark, however, is incorrect since
the margin is evidently shorter than theshell·length in all the measurable specimens· illustrated by BITTNER (1899, pl. 2,
figs. H, 15, 16, 17, 22, (20, 21)). Some
specimens of 11lltlttformis from Ussuri(BITTNEH, op. cit. pl. 2, figs. 18, 19) aresimilar to this subspecies in the heightlength proportion, but is distinguishedfrom it in the lower position of the lineof the maximum length.
Based on the minor differences in therib pattern KIPARISOVA (1!)38) distinguished three varieties among the Ussuri
specimens of multi/armis. None of them,
however, agrees with shio110sawensis.
Var. para KtPARisovA (1938, p. 287, pl.
3, fig. 1), whos';! ribs are arranged inaccordance with such a formula as1222221 or 133323331, may be nearest to
shiouosawensis so far as the larger number of radial striae is concerned, butthat variety has the coarser and much
more pronounced ribs of the 1st orderthan shionosawcnsis.
Very recently, NAKAZAWA (1953, p.
267, pl. 3, figs. lOa-b) described EttmorPhotis sp., aff. mttlliformis from theLower Triassic Yakuno group in Kyoto
Pref., Southwest Japan. It is represented
by a deformed left valve which is, when
restored, supposed to be nearly as longas high, and as remarked by NAI~AZA wA,
differs from multiformis in the lessdeveloped radial system of sculpture
and in the smaller height in proportion
to the length. In this respect, it cannot
be compared with slzionosaweusis.
E. mttlti/ormis from the Lower Triassic of Fukien, South China (CHEN, 1950,
p. 91, pl. 1, fig. 10) which is also represented by a left valve, is somewhat
allied to shimwsawensis, but is taller
and the exact comparison is impossible,
since the Fukien specimen is too poorly
illustrated.
Occurrence of "Ps." mulliformis was
also reported by WIRTH (1936, p. 434)
from the Lower Triassic of Szechuan,
but the specimen has not been figured.
DIENER's mttlliformis from the Lower
Triassic of Kashmir has nothing to dowith this species, because it has theobtusely truncated anterior and posteriorwings of the left valve which is not theEumorphotis muliiformis shionosawensis, subsp. nov. from Shionosawa

specific character of multiformis s.I.
The present authors are not sure whc·
ther multi/ormis from Siid Dolomiten(0GJLVIF.-GmmoN, 1927, p. 22, pl. 2, fig.
11) can be included within this species ornot, because it do~s not possess the narrow umbo characteristic of multiformis.
MANSUY (1920, p. 36, pl. 5, fig. 3)
illustrated a right valve from NongKong, Laos, and referred it to " Ps. "multiformis. Judging from the illustration, however, it is not taken for a
EttmorPhotis, since it bears no byssal
notch. The associated ammonites indi·cate that the Nong Kong faunule islater than the Early Triassic in age.
Lastly, E. nmlti'formis from the Oplziceras zone of East Greenland (SPATH,
1935, p. 7<1, pl. 22, fig. 8) is provided
with finer and less strongly differentiatedradial ribs than slzionosawettsis. The
East Greenland form is better to be
subspecifically separated from tmeltiformis s. str. at the least.
E. multiformis is further describedfrom the Lower Eo-Triassic of Wyoming (NEWELl. & KUMMEI., 1942, p. 957, pl.
2, fig. 10). This American form clif(ersfrom shimzosawe11sis at least in its larger
height-length proportion attaing 1.20 oreven more.
Occurrence: The Shionosawa limestone at the entrance of the Kamakakezawa of Shionosawa, Ueno·mura, Tanogun, Gumma-Pref. (~.I.!Wi!~!HIJU:JJ·HJl[
J 'iR)
References
RITTNER, A. (1899) Versteinerungen aus den
Trias-Ablagerungen des Siid·Ussuri·Gebides
in der Ostsibirischen Kiistenprovinz. 1\.lem.
Com. Geol., vol. 7, No. 4.
(19Jl) Uber Pseudomonotis tel/eri undverwandte Arlen der unteren Trias. Jahrb.
Ceo/. Reichsanst. Bd. 50 f;ir 1900.

11

CHEN, Pei·Yuan (1950) On the Marine Trias·
sic Fauna of Lungyen and Ningyang,
Fukien. Quart. ]our. Taiwan ~Ius., vol. 3,110, 2.
DJENER. C. (191:~) Triassic Faun1c of Kashmir.
Pal. Indica; 11. s., vol. 5, 110. 1.
- - (1923) Lamellibranchiata triadica. Fossi/ium Catalogus, Animalia, Pars 34.
klliKAWA, K. (1950) Chronological Classifica·lion of the Triassic Period in jap:m. Jour.
Ceo/. Soc. Japan. vol. 56.
- - (1953) Triassic Biochronology of Japan.
Papers su/Jmitletl to the 8th Pacific Sci.
Congr., 1953.
lWAI, S. (1947) Geology of the Eastern Partof the Santyu Graben. Bull. Tokyo Sci.
llfus., 110. 19.
KIPARJSO\'A, L. (1938) The Lower Triassic
Pelecypoda of the Us>uriland. Trav. Inst.
<:~ol., Akad. Sci. USSR, vo/. 7.
MANSUY. I-1. (1920) Fossiles des terrains
Mesozoiques de II region de Sam Neua,
Laos Nord-Ori('ntal. Mem. Surv. Geol. lndo·
chine, vol. 7, fasc. J.
NAKAZAWA. K. (1953) Discovery of Claraia
and EttmorPiwlis from Triassic Yakuno
Group, Kyoto Pref., Japan. Mem. Col/. Sci.,
lJniv. Kyoto, ser. B. tlo/. 20, 110 . .J.
NEWELl.. N.D. and KUMMEL, B. (19-1-2) Lower
Eo-Triassic Stratigraphy, Western Wyom·ing and Southeast Idaho. Bull. Geol. Soc.
America, vol. !i3.
OGILVJE·GORDo~. M.J\1. (1927) Das Gro:lener-,
Fassa- und Enncbrrg-Gebiet in den Siidtirolcr Dolomiten, usw. II Teil: Paliiontologie. Abhandl. Ceo!. Brmdesanst. Wien, Bd.
2·1/2.
SHIKAMA, T. (1952) The Lower Triassic Formation of Santyu-Graben. ]our. Geol. Soc.
Japan, vol. 58, 110. 686.
SPATH, L. F. (1935) Additions to the Eo·
triassic Invertebrate Fauna of East -Green·land. llfedd. om Gr<j.nland, bd..98, 110. 2.
WIRTII, E. (1936) Beitriige zur Kenntnis der
Trias in der Provinz Szechuan, West-China.
Neues ]ahrb. /. Mi11, usw .. Beit. Bel.. 75/B.

12

Koichiro !CHIKA WA and Yukio YABE

Postscript I
After the present paper had been completed,the senior author had the opportunity of read·ing the manuscript by H. OzAKI and T.
SHII\AMA on ·• Three Skytic Molluscs from
Gunma Prefecture, Central Japan " which is tobe published in Bull. Nat. Sci. Mus., N. S., t•ol.
1. 110. 2 (110. 35). Also he examined theirmaterials now deposited in the National Science
Museum at Tokyo. For their kindness thepresent authors wish to express thanks to Dr.
H. OzAKI of the National Science Museum at
Tokyo and Prof. T. SHIKAMA of the Yokohama
National University. Specimens of Eumorphotis
m~tltiformis illustrated by OzAJoa and SHIKAMA
are here referred to the subspecies describedabove. The right valve illustrated in fig. 1 (inOZAKI & SIIIKAMA) shows the characteristic
outline of this subspecies and the dotted line
at the antero-ventral corner of the figure maY

better be omitted. The opisthocline attitude ofthe left valve illustrated in fig. 4 is clearly the
result of the secondary deformation.
(October 3, 1954)

Postscript II
While the present paper is in press the following two papers by H. OzAKI and T. Sm.
KAMA appeared in Bull. Nat. Sci. Mus., N. S.,
vol. 1, no. 2 (no. 35).
1. On the Lower Triassic Formation of
Sionosawa Valley, Ueno·mura, Gunma Prefecture (in Japanese).
2. On Three Skytic Mulluscs from Gunma
Prefecture, Central Japan (in English).
The Shionosawa formation defined in theirfirst tnper is different from the Shionosawa
limestone defined in the present paper.
Oan. 20, 1955)

Explanation of Plate 2
E11morphotis multlformis (BITTNER) shio11osawensis ICJ!IKAWA et Y ABE, new subspecies
Right valve showing the outline of auricle. The ventral margin is not completely exhibited. (Reg. no. 5403) x 1
Fig. 2. Right valve showing the sculpture of the posterior auricle which is in tum unusually
protruded posteriorly. (Reg. no. 5403) x 1
Fig. 3. Right valve showing the outline of auricles. The ventral portion is not preserved. (Reg.
no. 5405) x 1
Fig. 4. Juvenile right valve. (Reg. no. OCU 252) x 1
Fig. 5. Left valve showing the characteristic anterior auricle and surface sculpture. (Reg. no.
5413) X 1
Fig. 6. Left valve showing the characteristic anterior auricle. (Reg. no. 5407) x 1
Fig. 7. Juvenile left valve. Auricles are not preserved. (Reg. no. 5408) x 1
Fig. 8. Left valve showing the anterior half of the narrow ligament area. The shell substanceis preserved only in the ventral half where the characteristic s::ulpture of this subspecies
can be well observed. Holotype (Reg. no. 5401) x 1
Fig. 9. Left valve. (Reg, no. 5409) x 1
Fig. 10. Left valve showing the characteristic posterior auricle. (Reg. no. 5410) x 1
Fig. 11. Right valve. The ventral portion is not preserved. (Reg. no. 5406) x 1
Fig, 12. Left valve showing the characteristic posterior auricle. (Reg. no. OCU 251) x 1
Fig. 13. Right valve showing the nearly complete outline. (Reg. no. 5402) x 1
Fig. 14. Left valve. (Reg. no. 5411) x 1
Fig. 15. Left valve. Somewhat prosocline attitude is possibly the result of the secondary deformation. (Reg. no. 5412) x 1(Specimens illustrated in figures 4 and 12 are deposited in Osaka City University, all others in
the Geol. and Min. Inst. Tokyo University of Education.)
Fig.

1.

lcH!I<A w A

and Y ABE :Eumorphotis multzfm·mis shionosawensis

13

14

PLATE

2

Trans. Proc. Palacont. Soc. Japan, N.S, No. 17, pp. 13-18, 1 text-fig., Pl. 3, Apr. 10, 1955

2GO.

DISCOVERY OF GLYPTOPHICERAS FROMHYOGO PREFECTURE, JAPAN*
KEIJI NAKAZAW A and DAIKICHIRO SHIMIZU

Geological and Mineralogical Institute, University of Kyoto!~fJI{lJ.'l;tJ.I? Glyptop/riccrJs Q)~J'l.: ~illll~~.:~~'ID)'tiH~M**U... rp Jt}t;.t:.>~l\J~lt.t..:?Rm~
1.!~-"f.:t.!iW.:. ::::1't*CifftWJJ!Jl~7?--t GlyPtoplziceras l.:liib-t :Mfrfm·~;b~.::. c.n:';t-?t..:o Htililttt:*rfl~/'i'1 C. t';tvc~, ~tJ:tilfftQ)~/i:W~'i!i"~.l.'1·e;b IJ. ~;fiQ)fu!:~tl!!lt~!lfl-e~,"?t..:o f.~ L Lepidolina toriyamai,
Ya~cina cf. yasubacnsis ~Q)f}j~.!l{~E;trJ:im=1Hi.!~~I:.IW~·~'j'~~' v :/ 7:~1:.11 t' :IJ.::_ "i:~L'C~, ~ t Q) G'l"lll9i Lf..:o .: Q)J1J!~I:t~lt!o!l'!f!?lfo7)ffl~imk7?--t t, Q) en£~ L. {)j:·lt"C Gl.vPtoPiziccras Q)W[

Nl~iil!IU Lt.:"

rtriJ-.!*=: • l\117k:*:1fRF>
and K. KoBAYASHI for the donation andto Mr. F. KATo of University of Kyoto
for photography.

In reconstructing a path for carrying
timbers in March 1953, K. KoBAYASHI
has happened to find a cobble with acast of an ammonite at Nakano-tani,
Tomisu-mura,ll about 8 km to the eastof Yamasaki-machi, Shiso-gun, Hyogo
Prefecture. The sample kept in the
Yasutomi Middle School at Anji-mura
was donated to the collection of University of Kyoto through the courtesy of Mr.
Keijun TATEBE of that school. Throughthis study, it is found to be a Glyptophiceras which has not yet reported in theJapanese Islands. In addition to its description some fusulinid species collected
near that locality are illustrated. The
writers wish to express their cordial
thanks to Prof. S. 1\fATsusmTA of Uni·
versity of Kyoto for his kind advices,to assist. Prof. K. KANJ\IERA of Kyushu
University for his suggestions on thefusulinid species, to Messrs. K. T ATEBE* Read Dec. 19, 1953; received Oct.

Geological Note
The deposits in the neighbouring areaof the fossil locality were taken for
Mesozoic in age on K. KoclllllF.'s geological map of Ikuno sheet in scale of
1/200,000 about 60 years ago. Since
then no geological investigation on thearea has been made. After the discovery of the ammonite, the writers
visited the locality several times, andespecially, the junior writer made asurvey of the area in the scale of 1/5,000.
The area consists of slate, sandstone,
conglomerate, and liparite, of which thelast occupying the summits of the moun·tains. The sedimentary rocks are classifiable as below; (see text-figure):Slate formation (I) ...... more or lesssheared, black slate, sometimes intercalating small, thin, lenticular
sandstone; more than 400 m. thick.

31,

195<1
t) ~llll*')~!fl:nw.·":rmwt-*~rfl '1'i-

13

14

Keiji NAKAZAWA and Daikichiro SHIMIZU
Sandstone formation (II) , dark blue,
fine to medium sandstone with intercalated, black, sometimes greenish slate; about 800 m. thick.
Slate and sandstone formation (Ill) ...
. .. . .. . . .. . black slate and dark grey
to dark blue sandstone in alternation, comprising fusulinid sandstone
and conglomerate; exact thickness
unknown.

The formation I is overlain by theformation I£ conformably, they strike in
N 10° to 30°E and dip southeastward at
30° to 60°, forming a monoclinal structure. On the other hand, the formation
III is variable in strike and dip, especially near the formation II, where theformer is presumably in fault contact
with the latter. The formation III contains in coarse sandstone a fusulinid
fauna cornposccl of Yabeina cf. yasubaensis TnRIYAMA (Pl. 3, Fig. 8), Yabeina
sp. (cf. Y. columbiana (DAWso=-:)) (PI, 3,
Figs. 5, fi), Lepido!ina toriyami KANMERA(Pl. 3, Figs. :1. 4, 7), Pseudodoliolina sp.
(Pl. 3, Fig. !I) and Scluvagerina sp. (Pl. 3,
Fig. 10) ; bryozoa? met with in a lenticular conglomerate composed of rounded
pebbles of chert, sandstone, shale, limestone, metabasalt, and acidic igneousrocks.
In the fusulinid fauna and rock-faciesof the formation it agrees well with thoseof the Upper Permian Kuma formation(KANMERA, 1953, 1954) in Kyushu and of
the Maizuru group and its equivalents in
the Maizuru zone (NAKAZAWA, 1950;
NAKAZAWA, SulK! and Sm:-.nzu, '1954;
NAKAZAWA and SHII\1, 1954), that theformation is safely correlated to them.
Though the formations I and II aredevoid of fossils, they are considered
Paleozoic in age, or older than the formation I, from their rock-facies. The
G!yptoplliceras-bearing cobble has beenobtained in the area of the formation
III.
Unfortunately, the writers could
not find any outcrop of the Mesozoic
strata which seemed to contain G!yp/ophiceras.
Occurence of G/yptopflicems
and its meaning

The rock specimen under consideration is about 15 ern and 13 em in diameter and 4 em in thickness, consistingof hard, bluish black, finely laminatedshale, and somewhat differs from theslate of the forniation nr in rock-feature.
This has been digged out as a cobble
from the river gravel under a small
wooden bridge. The fossil is an external cast only, with no suture-line, but
can be safely placed in the genus
Glyptophiceras by the external characterswhich agree very well with those of thegenus established by SPATJJ. The generic characters described by him are
as follows (SPATH, l!):lO, p. 33).
l\1ore or less evolute, round·vcntcrcd shellwith suture-line like Ophiceras. hut withcoarse sigmoidal costation. tending to degenerate into striation.
As already stated, the writers could
not detect the original locality fromwhich the gravel had been derived, butwere obliged to consider from the occurrence that the strata sought for wereshut in somewhere in the formation III
as a small lens.
The genus Glyptophiceras was considered to be confined to the lower division of the lower Eo·Triassic, i. c. Otoccratan (and Lower Gyronitan?) by SPATH(1934, p. 81). Its distribution is restricted to the Himalayas and East Greenland
as far as the writers are aware though
the intimate genus OPI1iceras (s.l.) ismuch more widely distributed. Gtypto-

Discovery of G/yptoplziceras from Hyogo Prefecture, Japanr

15

KAYA-·MURA

Texttigure. Geological sketch map of the Nakano-tani area. I: Slate formation,
II : Sandstone formation, III: Sandstone and slate formation, L: Liparite, a, b, c:
Fossil localities of GlyptoPhiaras, fu,ulinids and bryozoa? respectivelly, d: l'viaizuru
zone, e: Distribution of lnai series, f: Fossil locality of ammonites (1 : Nakano·tani,
2: Koge).

plziceras japonicum described below as
new species is more closely related to
the Himalayan species than to the East
Greenland. In Japan, the Lower Triassic
formations are much limited in distribution, namely, to the lower parts of theInai series in the southern Kitakami
mountainland and in the Maizuru zone,
the Iwai formation at Itsukaichi near
Tokyo, the Shionosawa formation in the
Kwanto mountainland, the Kurotaki and
the Tao formations in Shikoku. They
can be grouped into two in rock-facies,
although they are not strictly correlatedwith one another. The formations of
one group arc several hundred meters
thick, and are composed mainly ofsandstone and conglomerate, are rich inpelecypod fossils, and are distributed
over a fairly large area. They resemble the Lower Triassic formation of
Ussuriland in facies and fauna. The
formations of the other group are seve-ral scores of meters thick, composed
mainly shale and limestone, and distri·buted as small patches, and some arerich in cephalopod fossils. The firstgroup includes the lower parts of the Inai
series in the Kitakami mountainlandand in the Maizuru zone, and the second
includes the rest. The supposed " GlyPtoplziceras bed " under discussion may
belong to the latter group.
Among them the Tao formation isreferred to Middle Eo-Triassic from
Auasibh·ites-1\feelwceras fauna (Sm:rvnzu
and }IMBo, 1933). The lowest part of
the Inai series as well as the Kurotaki
and Shionosawa formations are considered to be Lower Eo· Triassic Tateanin age mainly from their pelecypod
faunas resembling that of Ussuri beds
(lclllKAWA, 1949, 1950), but have not yet
been confirmed to go down to Otoceratan
in age owing to the scarcity of cephalopod fossils. Only the Iwai formation

Keiji NAKAZAWA and Daikichiro SI!IMIZU

16

containing Ophiceras sp. nov. aff. demissum (0PPFr.) in SPATH and other fossils
is referable to that age (SHIMIZU, 1932).
Recently the senionr writer foundOphiceras (s.l.) sp., Xenodiscus? sp.,
Claraia aff. llecidens and other fossils
from the lower part of the Yakuno
group (NAr<AZAWA, 1953), and Ophiceras?
sp., Pseudosageceras aff. " i11fermouatanmn" HYATT and SMITH from the
Kusano formation of the Fukumotogroup (NAKAZAWA, SHIKI and SuiMizu,
1954) in the Maizuru zone. It is highly
probable that the Inai series in this zone
contains the lowest horizon of the Trias.
Jt is noteworthy that the specimen ha~been found in the area of the Upper
Permian formation of Lepidolina- Yabeina
zone, which is, like the Triassic forma·tion, a characteristic constituent of the
Maizuru zone. Moreover the Lower
Triassic formations in this zone are
generally coarse grained near the northern border, while they show a tendency
to become finer-grained southward.
From these points, it is considered thatthe area where the ammonite underconsideration has been obtained indicates the southern border of the Maizuru
zone and that the " Gtyptophiceras bed"
represents the lowest part of the Inai
series in this zone. A few years ago,the junior writer obtained a pebble with

G. japonicum

DiameterHeight of thelast whorl
Thickness of
the last whorl
Umbilicus!'i7mm.*an ammonite which had been pic~ed up
by a schoolboy of the Yamasaki HighSchool from the cultivated land at Koge
about 5 km WNW of Yamasaki-machi.
It is composed of bluish black shale
very similar to the shale with GlyPioPhiceras, but the ammonite is so erodedthat it can not be indentified. Unfortunately its original locality, too, could
not be conftrmed, but the strata aroundthe pebble-locality are very much likethose of the locality of the subject inquestion. It can be expected that theLower Triassic strata will be foundalong the southern border of the Maizuru
zone.
l>es(ription of Species
Ammonoidea
Family Ophiceratidae, ARTIIAHF.R, 1911
em. SPATH, 1930
Genus G/yptophiceras SPATH, 1930

Glyptophiceras japonicum NAKAZAWA
and Snn.uzu, n. sp.
Pl. 3, Figs. la. b, and 2

Diagnosis: An external cast is at handfrom a cobble of an unknown Mesozoic
formation. Its dimensions are as fol·lows:

Holotype of G.

Holotype of G.

hima/ayanum

gmcile40mm

47mm

16.. 28% (of diameter) 359~ (of diameter) 32% (of diameter)
16~6 () I6?G () 26% ()

28 50% () 40% (

) 47% ()

g·

* Measurements are approximately estimated, because the ventral margin is not preserved.

Discovery of Glyptophiceras from Hyogo Prefecture, Japan
Shell moderate in size, slightly involute, whorls compressed, whorl section
convergent, with, perhaps, narrowly
arched venter judging from the sectionof its gypsum mould (Pl. 3, Fig. 2),
umbilical wall rather steep, flank very
gently convex, with maxium breadth at
the umbilical rim, umbilicus fairly large
and shallow. Surface ornamention indistinct at a diameter below 5 rnm, thenconsistingof comparatively distantbulges gradually changing to rather
distant sigmoidal costae, and becoming
closer in advanced growth and at lastchanging suddenly to fine striae. Sutureline unknown.
Remarks and Comparisou: This specimen is represented by an external cast
only with no suture-line, but is surelyreferred to Glyptoplliceras by its characteristic ornamentation, coiling,andwhorl-section. This species has a close
resemblance to Glyptophiceras gracile,especially, its holotype specimen (SPATH,
1930, p. 34, Pl. VII, Figs. 5a, b) in ribbing and coiling, but clearly distinguished from the latter by the more compressed and subtrigonal whorl-section
like Ophiceras s.s. type. In this point
it has a closer affinity to the Himalayan
species, G. llimalayanum (GRIESBACH)(GRIESBACH, 1880, p. 111, Pl. III, Fig. 8;
DIENER, 1887, p. 41, Pl. XIV, Figs. 14 a,b, c), but differs from the latter in thelarger umbilicus and more closely-set
ribbing. (Reg. No. JM. 10111).

References
DIENER, C. (1897): Himalayan Fossils. The
Cephalopoda of the Lower Trias. Pal.
b1dica, ser. XV, Vol. II, Pt. 2.
GRIESBACH, C. L. (1880): PalaeontologicalNotes on the Lower Trias of the Iliamala·yas. Rec. Ceo/. Surv. India, XIII, Pl. 2.

1/

IcHIKAWA, K. (1949): Chronological Classification of the Triassic Formations in Japan.
]our. Geol. Soc. japan. Vol. 55, No. 650651, pp. 262. 263. (in Japanese).
- - (1950): Chronological Classification of
the Triassic Period in Japan. Ibid. Vol. 56,
No. 652, pp. 17-22. (in Japanese)
KANMERA. K. (1953): The Kuma Formationwith Special Reference to the Upper Permian in Japan. ]our. Ceo!. Soc. ]apatl, Vol.
56, No. 10, pp. 1-23. (in japanese withEnglish abstract)- - , (1954): Fusulinids from the Upper
Permian Kuma Formation, Southern Kyushu. Japan-with Special Reference to the
Fusulinid zone in the Upper Permian ofJapan. Mem. Fac. Sci. Kyuslm Univ., Ser.
B, Geology, Vol. IV, No. 1, pp. 1-38.
NAKAZAWA, K. (1950): Geological Age of theLimestone-conglomerate from Kawanishi·
mura, Kyoto Prefecture. Science of the
Earth, No. 2, pp. 38-40. (in Japanese)- - , (1953): Discovery of Claraia and Eumor·
Photis from Triassic Yakuno Group, Kyoto
Pref., Japan. Mem. Coli. Sci. U11iv. Kyoto,
Ser. B, Vol. XX, No. 4, pp. 261-269.
--, SHII<I. T. and SIIIMIZU, D. (1954):
Palaeozoic and Mesozoic Formations in theVicinity of Fukumoto, Okayama Prefecture.
]our. Geol. Soc. faPall. Vol. 60, No. 602.
pp. 97-105 (in ]ap:mese with English
abstract)
and SHIKI. T. (1954): Geology of theMiharaiyama District, Yabu-gun, Hyogo
Prefecture, Japan-with Special Reference
to the Triassic Miharaiyama Group. Ibid.,
Vol. 60, No. 704, pp. 192-201. (inJapanese with English abstract)
SHIMIZU, S. (1922): Ammonites found at lwaiin rv!usashi and Correlation of Life Zones ofMarine Lower Trias of Japan. ]our. Geogr..
Tokyo, Vol. XLIV, No. 516, pp. 93-107.
(in Japanese)- - and ]1111130, IV!. (1933): Cn the Triassic
Ammonites from Tao, !yo. Chikyu (TheGlobe), Vol. XIX. No. I. pp. 10-31. (inJap:mese)
SPATH. L.F. (1930): The Eotriassic Invertebrate Fauna of East Greenland. Medd. om
Grt/>nland, Bd. 83, Nr. 1.

18

Keiji NAI\AZAWA and Daikichiro SHIMIZU- - (193•1): Catalogue of the Fossil Cephalopoda in the British Museum (Natural

History).
Trias.

Pt.

IV. The Ammonoidea

Explanation of Plate 3
Glyploplticcras japo11icum NAKAZAWA and SHil\IIZU. n. sp.
Fig. la ................ External cast of holotype, x 1.
Fig. lb ............... Gypsum mould of the same, both sides of a crack being united,

XL
Fig. 2 ................. Restored whorl-section from the gypsum mould. x 1.
All figures below are x 10.
Lepido/i/10 toriyamai KANMERA
Fig. 3. sagittal section: Fig. 4. oblique axial section
L. cf. toriyamoi KAm.tERA
Fig. 7, diagonal section.
Yabcina sp. (cf. Y. columbia11a (DAWSON))
Figs. 5, 6. slightly excentric sagittal sections.
l'abcina cf. yasubacnsis ToRIYAMA
Fig. 8, axial section (outer volution being destroyed)
Pseudodo/ioli11a sp.
Fig. 9. parallel section.
Scltwagcri 110 sp.
Fig. 10, tangential section.

ofNAKAZA w A and SHIMIZU :Discovery of glyptophiceras

PLATE 3

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 17, pp. 19-22, Pl. 4, Apr. 10, 1955.

261.

NON-MARINE MOLLUSCA FROM THE PALEOGENE UCHIGOGROUP OF THE JOBAN COAL-FIELD, NORTHEAST
HONSHU, JAPAN*
YASUHIKO KAMADA
Nagasaki University, Nagasaki';.6~J;J!"i±lf'31lil;f?l'ltf .t I] ~FiM1~!iHI:.1Ci 099Ef! :111::W:'Ilt~W'dE 09~[~{\)f!! J: IJ (tJ&~<09~fi3Z.(ift71-<:f~.l'i.{f::.-;f:il1) Jmif.liJ:~iJH~ ~)vel..· J.>il:. ~W::!C<2(t Ml~-c9EJ'! ~hf-:. ~p([Jj.fi~ftEI::-:>1.. ·-c.i?ll-"'-'o:> -;t,.::?
.
v bl<.-.lI*Jm~l!f (Wfl"#f111:) 1'.$11)~]/k~Fm .l: IJ Corbicula tokudai (YoKoYAMA) (~:f.!ztj,l,j,~'j!i'/m~:;.I>:;M7,kl·h~

J:i!ii) ~. 3UCilfttfi1i;!ftfl"jJ: IJ Anodo11ta subjapanemis yokoyamai SUZUKI Oi&hl!r!:E:l!lUl111:~9!f.W~

7fl. V:li'!l:tlli!<HR1;M:i;::tlll~) H!Jt-:o riiJ:fi(±:lt~.fff.ti~~lli:~f:fim~ll¥ J: IJ "/tfji!H::- ffli lli -t 1.> oo-c ;b IJ. 3<.~;t;(tf~,i~f~'HlfC.Mifl:~f.Ltl:t!!.:lt~liii09Jt•~rilt:k~~liJimif.lii:¥G-tt'?)LH ·J.>o

Although there arc numerous reports
bearing· on the occurrence of marine
and brackish-water molluscs from thedifferent formations of the Joban coalfield, the present paper records the first
discovery of non-marine shells from thecoal-field.
The non-marine shells were collectedby the writer and Mr. Shun-Ichi SuZUI\I
from the Iwaki sandstone and Shiramizu
formation of the Oligocene Uchigo group,
the oldest Tertiary sediments in thecoal-field. The occurrence of the nonmarine shells serves to throw additional
light on the paleoecology and environment
under which they were entomb::!d. The
non-marine shells were collected fromthree localities, one belonging to a coalbearing formation generally ascriberl to
the S.hiramizu formation, and two to
the Iwaki sandstone. They comprise
one species and one subspecies, namely,
Corbicula to!mdai (YoKOYAMA), andA11odonta
subjapanensis
yokoyama£~m~ ~SUZlJKI.

Corbicula tolmdai was first describedby M. YoKoYAMA in 1932 under thegeneric name of Circe, but the subsequent studies of K. SuzuKI (1941-a)
which were based on a study of thehinge characters, proved its reference tothe genus Corbicula. He (SuzuKI, 1941a, b) stated that the species is one of
the most common corbiculids in the
Paleogene Ishikari group of the lshikari
coal-field and also in the Uryu group of
the same age in the Uryu coal-field.
This fact was subsequently upheld by
T. NAGAo and K. 0TATUME (1943), andby K. 0TATUME (1943).
Previous records show that the species
has been restricted to Hokkaido in its
distribution, but the present discovery
now extends its distribution to the mainisland of Japan. The specimens of Corbicula from the Joban coal-field werecollected from the upper course of theSatone River, Mizugami, Sekimoto-mura,
Taga-gun, Ibaragi Prefecture.
The Corbiczela bed of the above-* Read Feb. 28. 1953; received Oct. 15, 1954.
19

20

Yasuhiko KAMADA

mentioned locality consists of massive,
dark green, medium grained sandstone,
one meter thick and contains sporadically angular pebbles of green-colored amphibole-schist of the basement complex.
The sandstone containing accumulatedshells of Corbicrela in its middle part,overlies an oyster bank comprising shellsof Ostrea takiana YorwYAMA. The twoshell beds in the present area occupy a
position in the lower part of the Shiramizu formation. The Shiramizu is overlain conformably with the Iwaki sandstone and Shirasaka shale successively ;all four formations belong to the Uchigo
group.
Anodonta subjapanensis yokoyamai was
originally described by K. SuzuKI (1941)
on specimens from the Oligocene Uryu
group of the Uryu coal-field in Hokkaido.
Subsequently it has been reported from
the Miocene Osawa formation in thenorthern part of the Abukuma massif
in northern Fukushima Prefecture, andthe present record is its second outsideof Hokkaido.
The subspecies was collected fromtwo localities, one from the large cliff
about 200 meters east of Taki, Kadtmomura, and the other from Ohata,
Yoshima-mura, both in Iwaki-gun, Fukushima Prefecture. The specimens fromthe first locality, or at Taki, were collected from concretions embedded in thegray siltstone in which such plant remains as Sequoia also occur. Comptoniphyllum also occurs from the same cliff,
according to verbal information from
Mr. Fusao UEDA, who pr<!viously surveyed the area, but the writer was
unable to collect it. About twelve meters stratigraphically below the nonmarine shell bed just mentioned, there
occurs a sandstone bearing many brackish-water or marine shells as Ostrea
takiana YoKOYAMA, Trapezt'zem, Cyclina

and Glycymeris. Although there is no
development of the marine Asagai and
Shirasaka formations in the present
area, it is believed that the shell-beds
just mentioned may belong to the lower
part of the I waki sandstone from both
stratigraphical and paleontological evidence. Details of this evidence will bepresented in ar.other articl~.
The specimen from the second locality
or Ohata, is from a gray siltstone inwhich were found ramains of Glyptostrobus, Sequoia, Ficus and Carpinus (?).
This horizon occupies the middle partof the I waki sandstone in the Y oshima
area of the central part of the coalfield. The specimen compared with theothers from the first locality, is con·siderably larger and apparently of thinner test, but of the same external characteristics.
Probably the differences
shown in the size and thickness of thetest may have close relation with ecological conditions whieh may have beenslightly different owing to geographicalposition with the same district.
Before going remarks on the species,
the writer wishes to express his cordial
thanks to Professors Shoshiro HANZA w A,
Motoki EGucm and Kotora HATAI of
the Tohoku University, Scndai, for theirconstant encouragement and for kindly
reading the manuscript. Acknowledgements are also due to Mr. Shun-Ichi
SuzUKI, a graduate _student of the Mining
Department, Faculty of Technology,
Tohoku University, for kindly donating
his specimen from Ohata to the writer's
study. Thanks are due to Messrs. Yft
HtGucm and Koz6 NAKAJIMA for theirassistance in the field, and to Messrs.
Kimiji Kul\'iAGAI and Jy(t SATo for the
preparation of photographs.

Non-Marine Mollusca from the Paleogene Uchigo Group of t!1e Jobm

Family Corbiculidae

llleasurements :-(in mm)
LengthGenus Corbicula .MERGELE, 18ll

ca. 23.0

Corbicula lokuclai (Yoi<nYAMA)

225
22'4
20.4

Pl. ·1. fi~s. 4-9.

JR.2

Circe lokudai YoKOYAMA. 1932, ]our. Fac. Sci ..
Imp, U11iv. Tokyo, Sec. 2, t'Ol. 3, pt. 6, p.
24.0, pl. 2. figs. 3, ,t.

Corbicula atrala tokudai SUZUKI, 19•ll, Ibid..
Sec. 2. vol. 6. pt. 1. p. 9. text-figs. l, 2, pl.
l.figs.ll.l2,p1.2,figs.1-26; SUZUKI, I9,ll,
Ibid. Sec. 2, vol. 6, pt. 2. p. 32, pl. 2. figs.
6-12.
Corbicula tokudni NAGAo and 0TATUME, 19.J,3,}our. Fac. Sc., Ifoklmido Imp. llniv .. Sar.
.J, vol. 7, no. I, p. 7, no. I, pl. 3, figs. 4·9 ;0TATUME. 1943, Ibid. Scr. 4. vol. 7, no. 1,
p. 16, text-fig. 'L; 0TATUME, l9-t3, ]our.
Ceo/. Soc. Japan, Vol. 50, no. 599, p. 220;SuzUKI, 1949, faPa11. ]our. Geol. Geogr.,
l'ol. 21, nos. 1-·~. p. 121.

Rcmarlls :-Although, most of the specimens in the present collection are
broken and more or Jess deformed bysubsequent pressure, they are safely
identified with the holotype described by
M. YoKOYAMA (1932) from the Uryu
coal-field in Hokkaido. Most of thespecimens are somewhat longer thanhigh, roundly pentagonal in outline,with obliquely sublruncated posterior
margin, and a blunt edge runs fromthe beak to the postqro-ventral corner.
The shell surface is a'most smooth except for fine, incremental concentric
growth lines. The present specimens
are smaller than those figured by K.
SuzuKI (1941-a, b) and T. NAGAo andK. <hATUME (l!J13) from the Ishikari
and Uryu coal-fields is Hokkaido. The
differences in size b:!tween the present
and Hokkaido specimens may be due togeographical position, or in other words,
to different enviromcntal conditions.

21

Height21.2
ca. 190
20.9
18.3
17.7

Width
8.0
7.9
8.0
6.2

6.3

Valve
Right
Left
Right
Right
Left

Loca/ily and /ormatio1l :-Mizugami,
Sekimoto-mura. Taga-gun, Ibaragi Prefecture. (Ogawa) Lat. 36° 51' 24 11 N.,
Long. 140° 43 1 4511 E. Shiramizu forma·tion, Oligocene. IGl'S* coli. cat. no.
U007. Y. KAJ\IADA coli.
Family Unionidae
Genus A11odonta LAMARcK, 1799

Anodmzla subjapauensis yokoyamai
SUZUI\1Pl. 11, figs. 1, 2a-b, 3.

Nodu/aria cf. biwac YoKOYAMA, (not KoBr·:r:r,
1879; part) 1932, four. Fac. Sci .. Imp.
Uniu. Tokyo, Sec. 2, rot. 3. pt. 6, p. 243,
pl. 11, fig. 4.
Atlotlonta subjapanensis yokoyamai SUZUKI,
1941. Ibid., Sec. 2, val. li. pt. 2, p. 29, pl.
2, figs. 3a-c; SUZUKI, 19,!9, JaPan. ]our.
Geo!. Geogr., Vol. 21, nos. 1-4, p. 121;
KANNo, 1954, Sci. Rep. Tokyo Kyoiktt
Daigaku, Ser. C, vol. 3, no. 19, p. 83, pl. 6,
fig, 9.

Remarks :-As already mentioned above,
the three specimens of this subspecies
were collected from two localities in the
Joban coalfield, from Taki and the otherfrom Ohata. Compared with the typespecimens from the Uryu coal-field in
Hokkaido which was described by K.
SuzuKI, the Joban specimens are muchlarger, especially the left valve from
Ohata is more than three centimeters
longer. Although having a larger shell,* IGPS; abbreviation for Institute of Geology
and Paleontology, Semlai.

22

Yasuhiko KAI\IADA

they are safely identified with the typesubspecies. The present specimens aretansversely subellipticol in outline, havea long dorsal margin which forming an
obtuse but fairly distinct posterior angle,
a long and moderately straight ventral
margin which is subparalled to the dorsal, and an indistinct posterior ridge.

lHeasurements :-(in mm)
Length68
60
83

Height
40
37
5

Valve
Both (Taki specimen)()

Left (Ohata specimen)

Localities and formation :1) About 200m cast of Taki, 1\.acli'Jnomura, Iwaki-gun, Fukushima Prefecture.
(Ogawa) Lat. 36° 58' 46 11 N., Long. 140°441 4011 E. Iwaki formation, Oligocene.
IGPS coli. cat. no. 7.1003. Y. KAMADA
coli.
2) Ohata, Yoshima-mur;1, Iwaki-gun,
Fukushima Prefecture. (Taira) Lat 3r
031 18 11 N., Long. 140" 49 1 54 11 E. Iwaki
formation, Oligocene. Mining Department, Tohoku University Reg. no. 4. S.
SUZUKI coJl.

References
HATAI, K and KAMADA, Y. (1950) Fossil
Evidence for the Geological Age of the
Uchigo Group. Short PaPers It.PS, No. 2,
pp. 58-74, 2 text-figs.
KANNO, S. (1954) Non-Marine Fossil l\follusca
from Osawa-Pass, Fukushima Prefecture.

t•ol. 3, no. 19, pp. 75-86, 1 pl.
NAGAO, T. and 0TATUME, K (1943) The
Fossil Corbiculids from the Palaeogene
Ishikari Series in the Ishikari Coal-Field,
llokkaido. ] our. Fac. Sci., Ifokkaido ImP.
Univ., Ser. 4. vol. 7, no. 1, pp. 1-13, 1
text-rig .. 3 pis.
0TATU!viE, K. (1943-a) On Two Fossil Corbi·
culids from the Palaeogene Coal-bearing
Tertiary of Obirasibe, Tesio Province,
Hokkaid6. Ibid .. Ser. 4, vol. 7, no. 1. pp.
15-19, 4 text-figs.
- - (1943-b) The Fossil Corbiculids fromllokkaid6 and Kar:thuto. four. Geol. Soc.
Japan, Vol. 50, no. 599, pp. 216--222, 2
text-figs.
SUZUKI. K (1941-a) Some Non-1\Iarine Shells
from the Oligocene Ishikari Series in the
Ishikari Coal-Field, Hokkaido. ]our. Fac.
Sci., Imp. Univ. Tokyo, Sec. 2. vol. 6. pt.
1. pp. 1-11. 2 text-figs., 2 pis.
- - (19·tl-b) Notes on the Tertiary NonMarine 1'vlollus~a from the Coal-Field of
Uryu, IIokkaido. !bid.. Sec. 2, vol. 6, pt. 2,
pp. 13--37, 1 lext-fig., 2 pis.
- - (1941-c) On the Tertiary Non·Marinc
Shells Illustrated in K. ]lt-.IRo's ·· llokkaid6
Tisitu Ryakuron (Geological Sltetch of
Ilokkaido) ", 1890. ] our. Geol. Soc. Japan,
Vol. -18, no. 578, pp. 520-525, 6 text-figs.
- - (19-19) Development of the Fossil NonMarin~ Molluscan Faunas in Eastern Asia.
] apan. lour. Geol. Geagr., Vol. 21. nos.
1-4, pp. 91-133.
YoKOYAMA, M. (1932) TertiJry Mollusca fromthe Coalfield of Uryu, Ishikari. ]aur. Poe.
Sc., imp. Univ. Tokyo. Sec. 2. vol. 3, pl. 6,
pp. 221-247, 4 pis.

Sci. ReP. Tokyo Kyoiku Daigaku, Sec. C.

Explanation of Plate '1
Figs. 1-3, Anodonta subjapancnsis yakoyamai SuzUKI
Figs. 1, 2a-b: Loc. Taki, Kadono-mura, Iwaki-gun, Fukushima Prefecture.
Fig. 3: Loc. Ohata, Yoshima-mura, Iwaki-gun, Fukushima Prefecture.
Fiss. 4-9, Corbicula tokudai (YoKOYAMA)
Loc. Mizugami, Sekimoto-mura, Taga-gun, lbaragi Prefecture.
(all figures in natura! size)

PLATE 4

Non-Marine Mollusca from Joban Coal-field

KAMADA:

1

5

-,..

•
,

.

7

Photo. by KuMAGAI and SATO

8

9

Trans. Proc. Palaeont. Soc. Japan, N.S. No. 17. pp. 23-28, Pl. 5. Apr. 10, 1955.

262. OCCURRENCE OF A NEW SPECIES OF PLEURONECTITESIN THE TRIASSIC OF JAPAN.*
lVIASAHISA Al\lANO
Department of (;eology, Faculty of Science, Kumamoto University
El ;;l;:=:.:§':*Jtt G') Pleurollcctites -·1M!! G') .~Iii : 7.'~ cof.t:{frltm c· 3 -P:;t ,q;:~,&

l?lt, ·(1. 'f.:o 'Jit!l!!·~'t±~. "!o\litlln":cl~mt~;llffi-(7) t Q)·~tv~v"Jt.:iJ:. ~il1'~!Jl.rrRN·iJ: 11 :iJrfill~ ~Ill Lt.:!7)-c-=tJLI::'0~,·cJ'clliX Lf.:o~ ll!f ~ ?\.

Type species :-Pleurouectites laevigatus Scur.oTHEIM.
RemadlS :-Although the literatures

Ignoring Palaeozoic species, whose
generic references are dubious, Plcurouectites comprises 5 or more species all
known from the Triassic in Europe.
Therefore its occurrence in the Far
East is new to the science. Pleuronectites
hirabarensis, is proposed for this Japanese form. The specimens belong to thecollection of the Geological Institute,
University of Tokyo. The writer wishes
to record here his hearty thanks to
Prof. KoBAYASHI of the University, for
his kind guidance and reading themanuscript and to Prof. ENoo and Prof.
MATSUMOTO of Kumamoto University
for their encouragements.

accessible to the writer

are limited,

Ostracites Pleuroncctites laevigatus ScH·
LOTHEHv! and Ostracites Pleuronectites
discites ScHLoTHEIJ.\I may be two of theoldest (v. SEEBACH, 1861). The former
was referred to Pecten by BRoN:-; (1829),
and identified by GoLDFuss with Pecten
vestitus Gor.oFuss.
According to v. SEEBACH (1861),
Ostracites Plezwonectites discus andOstracites Pleuroncctites decussatus Sell·
r.oTIIEIM belong most probably to Pecten
discites BRoNI'. V. STROMBECK (1849)
quoted that "Unter dieser Species(=Pecten discites BRoNN) werden sam·mtliche nicht zu Pecten laevigatus
gehorige glatte im Muschelkalke bekante
Pecten zusammengefasst." These statements suggest that several laevigatuslike Pecten were called by the name ofPecten discites BRoNN. The generalcharacter of discites is said by v.
STROMBECK (1849) to be equi- or nearly
equivalve, and one variety has impressions radiating from the beak to twosides. PHILIPPI's figure (1900) shows theexistence of strong cardinal ridges between the ears and the main part of the

Family Pectiniclae LA:>.IARCK
Genus Pleuronectites Scm.oTHEIM

Diagnosis :-Shell highly inequivalve,pallial surface almost perfectly smooth,
except for feeble concentric striae. Right
valve inequilateral with rectangularanterior ear, whose anterior margin ismostly sigmoidal ; byssal notch deep andctenolium frequently present.
Leftvalve almost equilateral and a little
more convex than the right.

* Read Oct. 9, 1954; received Oct. 27. 1954.
23

l\1asahisa AMANa

24

shell inits inner surface.

Therefore

discites may be excluded from Pleuronectites.
Pleuro11eclites (?) sp. reported by
PHILil'l'I (19Q,l) from l'redazzo, Italy, issimilar to ToRNQUisT's Pleuronectites
beyrichi. This probably differs from
Plettronectites as PHILll'J'l himself assigned a question· mark, because theposterior half from the vertical line
through the beak is larger than theanterior, and very fine radial lines arerecognized on the shell surface by a
Iupe.
Two Pleuronectites are reported fromthe Palaeozoic, namely, Pecten (Pleuroucdites) devonicus FRECH from Germany
and Plcuro11ectites monotiden MF.RLA
from Italy. They, however, may beeliminated from Pleuroncctitcs by thereason that the former is only the left
valve, which is equilateral, with numerous radial ribs in the intervals among
the fine concentric lines. The referenceof Pecten (Pleuronectites) devonicas toPleuroncctites is questioned by SAr.o]l.!oN(1895). Of the latter, the figure anddescription are inaccessible to thewriter.

Pecten (Streb!opteria)

laterestriatus

was first reported by I'HII.li'I'l (1899)
with the thought of its being an intermediate form between St1·eb/opter£a andP/euronectites. It is quite different from
P/euronectites in the existence of radial
furrows near the marginal area, inequilaterality of the left valve, and theform of the right anterior ear. Nevertheless, this is Pleuronectitcs-like Pecten
as stated by Plllr.li'I'I. ScHMIDT has
called the same species as Pecten (Pleu·

roncctites) laterestriatus.
Pecten (Leptocholldria) aeolicus BnT:-<ER (1892) from Asia Minor was
identified with Pleuronectites alberti
Gm.DFUSs by ToRKQU!ST (1900). These

two are equilateral, and provided with
two sets of radial ribs which seem to bean essenti.ll specific character. ToRN·<-!UIST has noted on radial ribs on theshell surface of P/euronectites. Because
the radials of Pleurmzectites are notessential for the genus, however, thealberti-form is thought to be probably
eliminated from the Plezeronectites.
FRECH is of opinion that Pleuronectites
ScHLOTliEIM em. FISCHER is synonymouswith Streb/opteria M'coy and proposed
the name of P/curonectites prolaevigatus
for Streb/opteria laevigata M'coY. But,
as noted by SALOMoN (1895), it isevident that Pleuronectites differs fromStreb/opteria, in having a deep byssal
notch and ctenolium. After NEWELL,
the vertical range of Strcblopteria M'coY
is from lower Carboniferous to Permian(?).

The writer could not see any reference
to Pecten comPrcssus reported by STOP·
PAl"!. According to SALoMor.;, it is probably a Pleuronectites, because it is so
close to Plereronectites laevigatus as presumed a young of the species.
List of species :-In-so-far as the writer
can judge with references, the followings
belong to this genus.
1) Pleuroncclites beyricfti ToRNQUIST, ( 1899),

from Oberhalb Fantoni in Monte Spitz& Unterhalb San Rocco in Tretto, Italy.
2) Pecten comPressus STOPI'ANI, (1860), from
Ladinic of South Alps. (SALOMON, 1895,& DIENER, 1923).
3) Pleuronecfites laevigatus Scnr.oTHEIM, by
SALOM0:--1 (1900), from Nodosuskalk of
Neckar and Wellenkalk (?) of Elsenz.
Sc.:hwarzwald.
4) Pecte11 ( P/euronectites) lacvigatus ScH LO·
TI!E!M, by PHILII'!'l (1900), from
Muschelkalk of Weimar and Muschelkalkof s~eberg near Gotha, Thiiringen, andby ScHMIDT (1928), from mitt. Welleng~birge, Schwarzwald.
5) Pecle11 laevigatus SCI!LrJTHEIM, by EcK

Occurrence of a New Species of Pleurolleetiles in the Triassic of Japanabove hinge line ; umbonal angle about
90 degrees. Anterior car larger thanthe posterior, laterally elongated, subrectangular; hinge margin slightly concave upwards; anterior margin sigmoidal; distinct carina stretching from near
the umbo to antero-ventral corner, gradually thickened distally ; growth striae
sigmoidal; ventral margin bent up alittle, separated from the main part ofshell by deep byssal notch ; a row ofsmall holes aligned on the inner marginof the sinus, probably indicating ctenolium. An obliquely striated, lanceolate
area forms the inner wall of the sinus,
angulated at the top. The angulation,
however, dies out on the anti-umbonal
side. Posterior ear small, triangular,
ill-defined; growth striae fine, parallel
to posterior margin. Umbonal area alittle convex, while the remainder isnearly flat. Surface almost smooth but
2 or 3 concentric furrows may be present; with a binocular, feeble concentricstriae occasionally seen near the margin.
Left valve obliquely oval, almost
equilateral, but a half anterior to thevertical through the umbo is a little
larger than the posterior. Two ears
triangular, nearly equal (?) in size;
growth striae fine, subvertical. Although
the border with the main part of theshell is distinct near the umbonal region,
the linear walls are obscure as on theright valve. Umbo somewhat pointed,
elevated a little above straight hingeline; umbonal angle about 90 degrees;umbonal area convex, but gradually
flattened toward the pallial margin.
Surface smooth ; concentric growth striae seen near the margin.

(1862). from Muschelkalk of Ober·
schlesien, and by NoETI.ING (1880), froml\luschelkalk of Niedcrschlesien.
6)

Pee/ell laevigi/IIS BRoNN, by

25

STROMBECK(1849). fNm Mus::helkalk of N.W. Ger·
many, and by SEEBACH (1861), from
Muschelkalk of Weimar.
7) Pee/e11 ( Strcblopteria) lalercslria/us PHI·
l.IPPI, ( 1899). from Muschelkalk
ofSaargcbiet.
8) Pee/ell (Pleurol/ec/ili's) la/ereslriatus PHI·
LIPPI, by ScHMIDT (l928), from thesame as the preceding.
9) Pecten schmicderi GIEBEL, by SEEBl1CH(1861). from Muschelkalk of Weimar.
10) cf. Pecten schmiederi GIF.OEL, by Alii.BURG(1906). from Wellenkalk of Oberschlesien.
11) Pecten (Picurollecliles) schmiederi GIEBEL,(1856). from unt. Muschelkalk of Lieskau,(Sell MlllT, 1928).
12) P/eurOIICC/iles spp. by MATSUSHITA (1925),
from lower Trias of Kurotaki. Tosa.

Distribution :-It needs a more thoroughrevision to figure out an exact spatiotemporal range of the genus.
It is,
however, certain from the above list,that the genus including its type species
has most flourished in the Muschelkalk.
It occurs also in the South Alps andJapan.
Plcuronectites hirabarensis n. sp.
Plate 5, Figures 1-7.

Description :-Shell higher than long,inequivalve, and inequilateral especiallyin the right valve.
Right valve subcircular, but anterior
margin is more expanded anteriorly thanthe other and antero-dorsal a little concave, very inequilateral; a half anterior
to the vertical through umbo larger.
Umbo more or less pointed, not projected-------------------Measureme11ts :Hololype' (rig_h_t_v_._)_l

Heightca. 35 mm.

ca.

Lengthca. 31 mm.

I

Holotype (left v.)

29~~1.

ca. 27 mm.

jPara type (right v.)

I ca. 39 mm.

i ca. 34· mm.

- - - · - - - - -'--------------...!....---------~---

26

Masahisa AMANO

Observatio11 :-The left valve is usuallymore convex than the right. On thespecimen in figs. 6-7, a series of small
holes is seen below the anterior ear.
They may be the traces of the ctenolium. Growth striae are usually seenclearly on the ears but obscure in themain shell. With a magnifer, however,concentric striae can be seen in somespecimens near the margin.
Occasionally 2 or 3 oblique ribs arerecognized within a narrow furrowalong dorsal margin of the right anterior ear.
Most specimens before hand are secondarily deformed in different degrees
and manners. The outline of a specimen in fig. fi, was badly so depressedthat it became longer than high andgeniculated near t.he posterior andventral margins. The crape-like wrinkles
clearly visible in the paratype in fig. 2,
are disposed radially. They are probably
due to the thin shell.
Comparison :-At" a glance, the outlineof this species reminded the writer ofCamptonectes. Rut the surface ornamentation typical of Camptonectes cannot beseen on it. The distinct, antero-dorsal
linear wall and the arcuate hinge margin seem to show the characteristics ofEntolium. On the other hand, it coincides with European Pleuro11ectites in theinequivalved and inequib.teral shell,arcuate hinge margin with upward concavity, deep byssal notch under theright anterior ear, larger convexity of
the left valve than of the right, andthe simple ornamentation on the shellsurface, althoughthose are neverseen on Entolizem. Thus, it is certainthat this species resembles more Pleuronectites than any other genus. Judging from the Eutolium-like characters and the speciality of the sculptureof right anterior car, however, it is not

improbable to reveal a new genus byitself. The decision is left over until
better specimens will be procured.
Pleuronectites beyrichi ToRNOIJIST from
Tretto, Italy, differs from the present
species in the subsymmetrical outline
and the large apical angle of the rightvalve and the remarkably inflated left
valve.
The closest ally to this species isP/euro11ectites laevigatus Sci!LOTHEIM.
especially in fig. 338-b on p. 1!38 of " Die
Lebewelt unserer Trias" by ScHMIDT,
but is still distinct in the more protruded anterior margin, more circularoutline and in the anterior ear of theright valve. The moderately inflated
umbo is protruded above the hinge linein the left valve of that species. In
Pecten laevigatus BRoNN from Weimar
8 or 16 "Farbenstreifen" arc said by v.
SEEBAcH to exist rarely on the left
valve. In the description of Pleuronectites beyrichi, ToRNOUIST said that Pleuronectites laevigatus in good preservation has the distinct radial striae on
the right valve. Judging from thesestatements and illustrations of Pleuro1teclites laevigalus by several authors,
there may be 2 or more varieties inthat species
Among Japanese species, " Velafa"
sumerie11sis KanA Y AS Ill and kmKA w ,,from the upper Triassic in Sakawa
basin is most similar to this. It may
be a Plezeronectites, although the ctenolium can not be seen. It is specificallydifferent from Pleuroneclites lzirabarensis
in having fine and indistinct radial lines,
straight hinge margin, anteriorly truncated anterior ear and the longer outline of the shell.
This appears to resemble Camptonectes
triadicus NAKAZAWA and Velata maizurensis NAKAZA WA from the upper Triassic
Nabae Group, and Camptonec/es iorino-Occurrence of a New Species of Plcuroneclitcs in the Triassic of Japansuemis KuRATA and KIMURA and E1ttolium japonicum KuRATA and KIMURA
from the Jurassic of Sakawa basin in
one or the other aspect, but they are
generically distinct from this species.
MATSUSillTA (1937) reported 2 unnamed
species of Pleurouectites from the lower
Triassic of Kurotaki in Tosa. One ofthem is easily distinguished from thepresent species by the outline, convexity
and the general appearance of ears.
The other is represented by an incomplete fairly convex specimen without theumbonal region.
Occurre1Zce :-Collected by KATAYAMA(1938) at a small valley near Hirabara,
Omine-mura, l\1ine-gun in province Nagata, from the light purplish graycoloured shale in the uppermost part ofthe lower Carnic Hirabara formation in
the Mine series (RASE, 1950).

References
AHI.RIJRG, ]. (1906). Die Trias im slidlichen
Oberschlesien. Abhandl. kgl. Pre11ss. gcol.
Landesanst. & Bergakad. Neue Folge, 1/1.
50.
BITTNER, A. (1892), Triaspetrefakten vonIhlia in Kleinasien. ]ahrb. geol. Reichsanst.
Btl. 41. HI. 1.

- - (1899), Beitriige zur Palaeontologie, in·sbesondere der triadischen Ablagerungencentral asiatischer Hochgebirge.]ahrb. geol.
Reichsanst. Bd. 48. l/1. 3 & 4.
- - (1900). Ueber Pseutlomonotis Tellcri undverwandte Arlen der unteren Trias. ]ahrb.
gcol. Reichsanst. Bd. 50, Ht . .J.
DACQUF:, E. ( 1933 ). Wirbcllose des Jura, in
GliRicll's Leitfossilien. Lief.
DIENER. C. (1923), Lanwllibranchi:tta triadica,
Fossilium Cata/ogus 1. Animalia, Pars 19.
- - (1925). Leitfossilien der Trias. Wirbello~eTiere und Kalkalgen. in GiiRicH's Leitfos·
silien, 4 Lief.
and KUTA5SY, A. (1923·1931), Lamellibranchiata triadica, Fossilium Catalo&us 1

27

Animalia. Pars 19 et 51.
EcK. H. (1862). Ueber den opatowitzer Kal·
kstein des oberschlesis::hen Muschelkalks.
Zcilschr. deutsch. geol. Ges. Bd. J.J.
FRITZ, F. (1891), Die devonischen· Aviculiden
Deutsch lands. Abhaudl. ZIIY geol. specialkarte
von Preuss. ttlld den fhiiringischen Staaten.
Berlin. Bd. 9, Ht. 3.
HAsE. A. (1950). The Stratigraphy of theTriassic System in the southwestern p1rtof Yamaguchi Prefecture. Sci. Rep. Fac.
Sci. Kyushu U11i11. Ceo/. Vol. 2. No. 2.
KATAYA!IIA, M. (1938). Stratigraphy of Mine
Series in Prov. Nagato. The graduation
thesis from Imp. Univ. of Tokyo.
KI:-.ItiRA. T. (1951 ). Some Pectinids and a
Limid from the Jurassic Torinosu Groupin Japan. ]our. Fac . .C:ci. Univ. Tokyo, Sect.
2. Vol. 7. Pis. 6-10.
KORAYASHI, T. and lcllll\AWA, K. 119,~9),TosaPecten. gen. nov. and other uppl'r
Triassic Pectinidae from the S3kawa b:1sinin Shikoku. Japan. Japan. ]our. Geol.
Geogr. Vol. 21.
1\IATSllSIIITA, S. (19:~7). Fossils of the lower
Triassic Period found in Tosa Province.
Chikyu· The Globe, Vol. 5, No. 5.
!\IERLA. G. (1933), La fauna del calcare alkl/eropJum della Regione D.>lomitica. Pal·
aeon!. Zentralb. 1933-34.
NAI<AZAWA, K. (1952). A study on the
Pelecypod-Fauna of the Upper Triassic
Nabae Group in the Northern Part of
Kyoto Prefecture, Jap:lll. Mem. Col/. Sci.
U1riv. Kyoto. Ser. B. Vol. 20, No. 2.
NEWELl., N. (1938). Late Paleozoi..: Pelecyp:>ds:
Pectinacea. Kansas Geol. Surv. Vol. 10.
NoETLINI;, F. C 1880), l>ic Entwicklung der
Trias in Niedcrschlesien. Zeitschr. deut.~ch.
gcol. Ges. Bd. 32.
PIIILII'I'I, E. (1898), Beitr:i_tte zur 'Morphologic
undPhylogenie fler T.amellibranchier.
Zeitsclzr. deutsch. geo/. Ges. Btl. 50.
- - (1899), Uher zwei neue Zweischaler·
Arten von palaozoischem H:1bitus aus
deutschem Muschelkalk. Zeitschr. deufsch.
geol. Ges. Bd. 51.
- - (1900), Beitrage zur Morphologic und
Phylogenie der Lamellibranchier. Zeitsclrr.
deutsch. geol. Ges. Bd. 52.

28

Masahisa AMANO

Pill tll'P, H. (1904), Paliiontologisch·geologische
Untersuchungen aus dem Gebiet von Predazz'l. Zeitschr. deulsch. geof. Ges. Bd. 56.
SAr.oMoN. W. (1865), Geologische und Pala·
ontologi~che Studien iiber die 1\lnnnolata.
Paliiontogr. Bel. 42.
(1900), Ueber Pseudomonotis und Pfertro·
11Ccli/es. Zeilsclzr. deutsch. geol. Ges. Bd. 52.
- - (1902), Die Familienzugehorigkeit der
Pfcuronectites. Zentralhf. f. Min. Ceo/.
Palaeo11t. Vol. 3.
ScHMIDT, M. (1928). Die Lebewelt unserer
Trias. Ohringen.
SEEBACH, K. (1861 ), Die Conchylien·Fauna

der W eimarischen Trias. Zeilschr deulsclz.
geol. Gcs. Bd. 13.
STI<oMBECK. A. (1849), Beitrag zur Kenntniss
der Muschelkalk·bildung im nordwestlichen
Deutschland. Zeitsclzr. deutsclz. geol. Ges.
IJd. 1.
ToRNlllJIST, A. (1899 & 1900), Neue Beitriige
zur Geologie und Palaontlogie der Umgeb·
ung von Recoaro und Schio. Zeitsclzr.
deutsclz. geo/. Gcs. Bd..51-!>2.
Wli.SCIIOWITZ, J. (1944), Erster Bericht iiber
eine neue Fundstiitte unterdevonischer
Fossilien im Ost·Urlich (Alvater-gebirge ).
Neues fahrb. Ref. 1'eil, 3.

AMANa :PLATE 5

Triassic Pleuronect£tes

4

4'

U EKI photo.

Explanation of Plate 5
Pleuronectites hirabarensis AMANa, n. sp.
Fig. 1. Holotype: Exterior of right valve, x 1: Fig. 1'. Restored figure, x 1.
Fig. 2. Paratype: Exterior of right valve, x 1.
Fig. 3. Holotype: Exterior of left valve, x 1.
Fig. 4. Interior of right valve, x 1: Fig. 4 1• Showing lanceolate area (a), x 2.
Fig. 5. Depressed right valve: Exterior, x 1.
Fig. 6. A series of holes on right valve, x 6.
Loc. Hirabara, Omine-mura. Mine-gun, Nagata.

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CONSTITUTION
of the
PALAEONTOLOGICAL SOCIETY OF JAPANARTICLE 1. Name
The Society shall be known as the Palaeontological Society of Japan. The Society is a sectionof the Geological Society of Japan.
ARTICLE 2. Object
The object of the Society shall be to promote the study of palaeontology and related sciences.
ARTICLE :1. Achievement
The Society in order to execute Article 2 shall ( a) issue the Society journal and other publi·
cations, ( b ) hold or sponsor scientific lectures and meetings, and (c) sponsor collecting or
field trips, and lectures.
ARTICLE 4. Membership
The Society shall be· composed of persons who are active of interested in palaeontology or
related sciences, and shall be known as regular members, honorary members, and patrons.
ARTICLE 5. The members of the Society shall be obliged to p:ty annual dues to the Society, forwhich they shall enjoy the privilege of receiving the Society's journal and of submitting
papers which have been read and discussed at the meetings for publication in the Society's
journal.
ARTICLE 6. Administration
The Society shall have the following organizations for its administration.
(a ) General meeting. The general meeting shalJ be composed of the Society members. Morethan one tenth of regular members shall be present to hold general meetings. Administrative affairs shall be decided during the general meeting.
(b) President. The president shall be elected from among the regular members. The president
shall represent the Society and supervise its business matters.
(c) Council. The council shall be composed of councillors who are elected from among theregular members. The council shall discuss ad111inistrative affairs.
(d) Business council. The business councillors shall be elected from among the council members, and shall administer business affairs.
(e) Officers shall be elected by vote of returned mail ballots, as a general rule.
ARTICLE 7. Amendments to the constitution shall. be by decision of the general meeting.

By-Laws and Administration
ARTICLE 8. The Society's journal shall be issued quarterly.
ARTICLE 9. Regular members shall he persons· who have knowledge, experience, or interest inpalaeontology or related sciences.
ARTICLE 10. Patrons shall be selected individuals or organizations who give special support to theobjectives of the Society.
ARTICLE 11. Honorary members shall be per,;ons of distinguished achievement in palaeontology.
The council shall nominate honorary members for decision by the general meeting.
ARTICLE 12. Applicants for membership to the Society shall submit their full name, mailing ad.
dress, date of birth, occupation, and name of school from which they graduated.

Dues
ARTICLE t:l. Rates for annual dues of the Society shall he decided during the general meeting.
Annual dues for regular members are Yen 600.00 (domestic members) and U.S. $3.00 (foreign
members). Patrons are individuals or organizations donating more than Yen 15,000.00 annually. Honorary members are free from obligations.
ARTICLE 14. The Society income shall be from membership dues and bestowals.
ARTICLE 15. The Society shall have one chairman, fifteen councillors, and several business council·
Jars, whose term of office shall be two years. They may be re-elected.

Addendum
ARTICLE 1. There shall be four business councillors for the present.