a -lt" ~ .t. ~ t-t ~­•%·;c.f
Transactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 2Palaeontological Society of Japan'

June, 30, 1951

CONTENTS
TRANSACTIONS
197. New Species and Genus of the Foraminifera of the Cenozoic Formationsin the Middle Part of the Boso Peninsula, Chiba-ken.

. . . .
Takayasu Ucuw

33

198. Notes on the Entomonotis-bearing Triassic Formation at Iwai near
Itsukaichi, Tokyo Prefecture, with a Description of a new Etzlomottolis. . . . . . . . . . . . . . . . . .

. Koichiro lcuiKAWA

43

199. On the Myophorians from Kyoto Prefecture (Prov. Tango) . . . . .
. . Nobukazu KAMBE•200. Pliocene

Pinnipcd

Remains from Kanazawa, Ishikawa

Japan. . . . . . . . . .

49

Prefecture,

Yoshio KAsENo 57

President:

Hisakatsu Y ABECouncillors:

Kiyoshi AsANo, Ryuji ENDo, (Business and Accountant), Seido

ENoo,

Haruyoshi FuJIMoTo, Shoshiro HANZAWA,

Ichiro HAYASAKA,

Tciichi KoBAYASHI (F..ditor), Jiro MAI<IYAMA, Tatsnro MATSUMoTo, Masao
MINATo, Tsuneteru OINOMJcAoo (Publication), Tokio SIIIKAMA, Koiti
SuzuKI, Fuyuji TAKAI (General Affairs), Hisakatsu YAnE.

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

Trans. Proc. Palaeont. Soc. Japan N.S., No. 2, pp. 33-42 June. 1951.

197. NEW SPECIES AND GENUS OF THE FORAMINIFERA OF
THE CENOZOIC FORMATIONS IN THE MIDDLE PARTOF THE BOSO PENINSULA, CHIBA-KEN, JAPAN*
TAKAYASU UCHIO
Faculty of Engineering, University of TokyoJ)Hf. .!f': ~ r11 til' UJif !t f~ 11-#. V) fHL!Il V);w[flz,t V::laf1m : VJ!f. ~ .l'ft lflli" UJ :Jc§. · 1i.: mt.ttl! IIi& V:~
lltt$l*t!Hitfli:UJlfi4:.ftUJ ifililftl'P !>.f!}r.: ::fHL.!Il. UJlfiJir!)ltV:tlifl!i ~ !clt L. "C ~> o o :Jc~1f::itl!7J.it Q) t
101~-:::>"·"CtJ:.fi-::>"C ::mmttltilftlt~ti15$. i~i4~,~-fl!lilalt (;Jn~) t.r.:~·. .:: .::•~.Jii.v:t~t&D!•~

11ae t... "C "'-' o o*§il · !i:W.:itl!IK J: !l ~ Pseudoeponides japonicus, Cassidulitra asatroi, C. t~akamuroi, Enklsolenia margitrata var. semistriata (J:JJ:f;ti'Jlfclt), E. ozawai sp. nov., E. circulo-cosla var.
carina/a nov., Heronalle11ia otukai sp. nov. ~ iicll& L, ~Pifmfli:»· !> IJ: Pyrgo depressa var.
tomiyetrsis nov., Cassidulina tomiyensis sp. nov., Bolit'itra otukai sp. nov., l.oxDstomrm koikei sp.
nov., Entosolenio marginata var. cushmani sp. nov., E. morgitrata var, angula/a nov.,
Vagocibicides nipponicus sp. nov. ~licit L -c .t> o o Pi.ll!:i1if¥:

species of foraminifera from the Cenozoic Formations at Minato-machi21 in thewestern part of the middle Bosfl Peninsula, near Tokyo Bay. The manuscriptof the foraminiferal assemblage of eachformation of this district was read at
the monthly meeting of the Geological$ociety of Japan held on 21th Oct. 1950
to describe the following new species :Pyrgo depressa var. tomiyensis nov.,
Bolivina otukat' sp. nov., Loxostomum
koikei sp. nov., Etttoso/enia marginata
var. cushmani nov., E. margitzata var.
angr1lata nov., Cassidulina tomiyensis sp.
nov., Vagoribicides nipponicus sp. nov.
All the registered type specimens ofthese new species are deposited in the
Geological Institute, Faculty of Science,
University of Tokyo.
The writer wishes to express his
cordial thanks to Prof. K. UwATOKo, thelate Prof. Y. OTUK A and Dr. Leo. W.
STAcH for their kind advices in field

The new species and genus describedin this paper are sampled from two
districts of the middle part of the BOso
Peninsula, Chiba-ken.
Geology andpalaeontology in Otaki Gas Field werealready published in Japanese in theprevious paper,l> in which the writer
briefly described foraminiferal assemblages and new species and genus.
Thereafter the manuscript3' describing
detail zonules and sampling method of
the foraminifera is submitted to the
Geological Society of Japan to be printed
in the near future. The present paper
describes the new species and genus in
detail to determine Pseudoeponides japonicus gen. et sp. nov., Heronallenia
otukat' sp. nov., Cassidulitta asanoi sp.
nov., C. nakamurai sp. nov., Entosolenia
marginata var. semistriata nov., E.
ozawai sp. nov. and E. cirulocosta var.
carinata nov.
The writer has also described new• Read Dec. 2nd, 1950; received Nov. 6th, 1950
33

34

Takayasu UCHIO

and laboratory works.
This shortpaper is dedicated to late Dr. Yanosukc
OruKA, Professor of Structural Geology,-Geological Institute of Tokyo University.

Description of New Species
Family Miliolidae
Genus Pyrgo DEFRANCE, 1842

Stratigraphical sequences in these
districts are shown in thefollowing Table indescending order :( Otaki-Mobara district)
Kasamori
1\Iandano

Fotmation}.
Pleistocene
Forma t10n
ChonanFormation}
Kakinokidai Formation Plio-Pleistocene
Kokumoto
UmegaseOtadai
KiwadaFormation}
Formation.
upper Pliocene
Format10n
Formation,(Minato·machi district)
Sanuki1Jiltstone}
Pleistocene
Nagahama sand & gravel··· ···············unconformity··················
lwasaka fine sandstone}
upPJ~~ene
Komaba tuff-breccia
Tomiyatuffaceous sandstone
Hagiu
pyroclastics }Inagozawa mudstone
lower Pliocene
Senhataconglomerate··· ··· ············unconformitY··················
Amatsumudstoneupper Miocene

Sanuki siltstone and Nagahama sandand gravel are quite the same ·with
Kasamori Formation and Mandano
Formation in Otaki-Mobara district
respectively. Tomiya tuffaceous sand·stone may be correlated with Mimata
shell bed of Kiwada Formation byforaminiferal assemblage.

Genotype Pyrgo lae~·is DEFRANCE

Pyrgo depressa var. tomiyensis
UcHio, var. nov.
Plate. 3, Figures. 9 a, b.

Description :-Test in front viewnearly circular, compressed, toward the
periphery extending out into a thin
carina, in end view ellipsoid, the edge
angled and drawn out into the carina;
ventral chamber is very small, about 2/5
times as large as dorsal chamber, notcircular; wall smooth, dull white; aperture broad, without a neck, the tooth onventral side wide, extending nearly thewhole width of the aperture, and in end
view nearly filling the opening, leaving
the actual aperture but a narrow slitlike opening.
Holotype :-Reg. No. CF 3014 in tuf·
aceous coarse sandstone at Loc. 11,
type-locality of Tomiya tuffaceous sand·stone ( Tomiya. Takeoka-mura, Kimitsu·
gun, Chiba-ken), 100m. SWW of Kazusaminato Railway-station on West Boso
Line (upper part of Tomiya tufaceous
sandstone, upper Pliocene) Length ca.
0.68 mm. thickness ca. 0.41 mm.
Comparision :-Variety differing fromtypical one by having always muchsmaller ventral chamber than dorsal
chamber; variety also easily distin·
guishable from P. depressa var. murrhy1la by having much smaller ventral
chamber and no neck.
Ocwrre1zce and geological age :-Not
rare, only known from type-locality
above mentioned, upper Pliocene.

New Species and Genus of the Foraminifera of the Cenozoic Formations

Family Buliminidae
Genus Bolivina n'ORBIGNY, 1839
Genotype: Bolivina Plicata n'ORBIG:-.'Y

Bolivina otukai UcHio, sp. nov.
Plate. 3, Figurc:s. 7 a. b.

DescriPtion :-Test compressed, moreor less broader than long, broadest at
the middle part of the test, somewhat
triangular-shaped; chambers numerous,
narrow; sutures distinct, much limbated,curved; wall finely perforate ; apertureelongate, narrow.
Holotype :-Reg. No. CF 3012 in finesandstone just above tuff at Loc. 6A,
type-locality of Iwasaka fine sandstonealong sea-cliff, about 500 m. north ofKazusa-minato Railway-station on West
Boso Line (middle part of Iwasaka finesandstone, upper Pliocene). Length ca.
0.23 mm, width ca. 0.29 mm.
Comparision :-This new form is easily
distinguishable from any other speciesof the genus by having much limbatedsutures, periphery and broader test.
Occurrence a11d geological age :-Only
one specimen at type-locality above
mentioned, upper Pliocene.
Remark :-The specific name is dedicated to late Dr. Yanosuke ChuKA,
Professor of Geological Institute of Tokyo
University.
Genus Loxostomzem EHRENBERG, 1854
Genotype: Loxostomum subrostratwn

EHRENBERG

Loxostonzum koikei Ucnro, sp. nov.
Plate 3, Figures 6 a-c.

Descriptio11 :-Test compressed, elongate, broadest in the middle part of thetest, apical end truncated, distal end

35

rounded ; chambers distinct, numerous ..
becoming larger as added; suturs distinct, much limbated ; periphery somewhat tricarinated particularly on lower
half, namely, a slightly projected mediankeel between angled margins of bothsides ; aperture terminal, fissurine orvery narrow, elongate, entosolenian.
Holotype :-Reg. No. CF 3013 in tufaceous coarse sandstone at Loc. 11, typelocality of Tomiya tufaceous sandstone(Tomiya, Takeokamura, Kimitsu-gun,Chiba-ken), 1000 m. SWW of Kazusaminato Railway station on West Bosu
Line (upper part of Tomiya tufaceous
sandstone, upper Pliocene). Length ca.
0.55 rom, width ca. 0.30 rom.
Comparision :-This new form is easily
distinguishable from any other speciesof the genus by having much limbatedsutures and somewhat tricarinatedperiphery.
Occurrence and geological age :-Only
one specimen at type-locality above
mentioned, upper Pliocene.
Remark :-The specific name is dedicated to Mr. Kiyoshi KoiKE who madegeological survey of this district.
Genus Entosolenia EHRENBERG, 1848
Genotype: Entosolenia lineata WILLIAMS01'\

In view of the recent progresses ofJapanese Cenozoic Stratigraphy by micro·
fossils, especially by Foraminifera, str:ct
identification of species is demanded.
For this purpose the writer has madepalaeontologically foundamental researchof the genus Entosoletzia. A study ofthe various collections of foraminifera
now stored in the Institute of Petroleum
Engineering, Tokyo University, Japan,
has rendered the writer possible toreview the Japanese species of Entosolenia, both fossils and recent. JapaneseForaminiferists have adopted the clas-

36

Takayasu UCHIO

sification by J. A. CusHMAN except about
Nodisariidae, GALLOWAY's classificationof which is adopted generally. According
to GALLOWAY, Ooli1za D'ORBIGNY, 1839;
Fissurina REuss, 1850 and Obliqttitta
SEGUENZA, 1862 are valid, while CUSHMAN
adopted Entosolenia EHRENBERG, 1848 forthese genera. These genera belong to
the Family Nodosariidae and Buliminidae
according to GALLOWAY and CUSHMAN
respectively.
The description of the genus Oolina
D'0RBIGJW, 1839 is "Test free, monothalamous, ovate, round in cross section;wall hyaline, very finely perforated,smooth, costae or otherwise ornamented
without or with apical spine or spines;
aperture entosolenian, rounded, simple,
sometimes with radiating grooves orridge around the external part of theaperture"; compressed forms otherwise
like Oolina belong to Fissttrina REuss,
1855 and excentric forms otherwise like
Oolitza belong to Obliqui1za SEGUENZA
1862. These three genera have monothalamous test and entosolenian aper·ture, and this is why CUSHMAN adopted
Entosolenia EHRENBERG 1848. The difference among Oolina, Fissr~rina andOblifJttina is very scarce and in thespecific category, therefore the writer
has adopted CusHMAN's classification.
As many authors have confused, it isdifficult to discriminate strictly thesegenera and Lagena WALKER et JAcoB,
1798. Most species of Lagena of many
authors may belong to Entosolenia. Of
many different species of Entosolenia
hitherto distinguished from writer's collection the following species are valid,
namelyE11tosolenia marginata (WALKER et BoYS)
E.
marginota var.
cushmani
UcHIO, nov.
at1gu/ata
marginata var.
E.
UCHIO, nov.

E.

marginata var.

E.
E.

citCI4IO·COSia (ASANO)
circul a. costa var. carinata

E.
E.

orbignyana (SEGUFNZA)
orbignyana var. lacuna toE.

orbignyana

E.

Otbigttyana var. coronataE.

orbignya11a staphyllearea

E.
E.
E.

laet•igata (REUSS)
globosa (MONTAGU)
ozawai UCHIO, sp. nov.

semistriata

UCHIO
UCHIO, nov.

(BURROWS et HOLLAND)
var. cloth rata

(BRADY)(SIDEBOTTOM)(SCHWAGER)

Besides these species CusHMAN and
BRADY reported following recent species
near Japan, that is,E.

orbignyana

var. cremtlalaE.

orbignyana

var. alata(CUSHMAS)(CUSHMAN)

Entosolenia margi11ata var.
semistriata UcHio
Plate 3, Figures 12 a, b.
Etztosolenia semislriata UCHIO, jour. Assoc.
Petrol. Tech., 1950, vol. 15. No. 4, P.
190, Fig. 15. (in japanese)

Description:-Test circular or slightly
ovate,

quite similar tothat ofE.

margitzata (WALKER & Boys), but difering from typical one by having several
fine costae and sometimes also fine pits
on the lower half of the test ; aperture
fissurine, entosolenian.
Holotype :-Reg. No. OF 3005, in
mudstone beneath 015 B Tuff at Locll119 B about 1600m. southeast of Shoryuji,
Nakagawa-mura, Isumi·gun, Chiba-ken.
Length ca. 0.20 mm. Width ca. 0.18 mm.
Thickness ca. 0.13 mm.

New Sp?cies and Genus of the Foraminifera of the Cenozoic Formations

37

Occurrence mzd geological age :-Rarein "Otadai," "Umegase ", and '' Kokumoto " Formation, all upper Pliocene
formation of Boso Peninsula.
Entosolenia ozawai UcHio, sp nov.
Plate 3, Figures 10 a, b.

Description:- Test cylindrical, tapering
to ap'cal end, round in apertaral view,
truncate and flat or concave at initialend, broadest in middle part of the test,
surface ornamented with many longspiral costae ; running from initial toapical end ; apertare rounded, entosolenian.
Holotype :-Reg, No. CF 3006, in sandy
mudstone at Loc.. ll-215, Odoro, Kamltakimura, Jsumi-gun, Chiba-ken along
Otaki·ChOnan High-Way.
Length ca.
0.18 mm, width ca. 0.12 mm. (Upper partof Umegase Formation, Upper Pliocene)
Occurrence :-Only one specimen at
type locality above mentioned.
Remark:-The specific name is dedicated to late Dr. Yoshiaki OzAwA.
Entosolenia circulo-costa var.
carinata UcHio, var. nov.
Plate 3, Figures 11 a, b.

Description :-Variety with much compressed test, surrounded by a wide thin
carina ; wall ornamented with two prominent circular raised rims about the
body proper : aperture fissurine, entosolenian.
Holotype :-Reg. No. CF 3007 in sandy
mudstone just above C3 Tuff at Loc. 34,
Hoonji, Nishi-mura, Chosei-gun Chibaken (lower part of Chonan Formation,
Pleistocene). Length ca. 0.23 mm, width
ca. 0.17 mm, thickness ca. 0.14 mm.

Text-figs
Entosolenia cioculo-costa(ASANO)
Copy of the original figures

Comparisiou :-Variety differing from-typical form by having a wide thin
carina and far more prominent circularrims than those of the latter, therefore
in apertural view, the former resembles
E. orbignymra and the latter E. margi11ata. Variety also easily distinguishable
from typical one by having smaller test,
general outline of the test and aperturalcharacter.
Occurrence :-Fairly abundant at typelocality above mentioned.
E1ztosolenia marginata var. cuslttnam·
UcHio, var. nov.
Plate 3, Figures 13 a, b.

Lage11a marginata var. CUSHMAN, 1933,
U.S. Nat. Mus., Bull. 161, Pl.
4, Figs 14a. b, P. 17

This new variety is formerly reported
as E. marginata by many authors, but]. A. CusHMAN always described this as
E. margi11ata var. Variety quite resembles the typical E. margi~tata (WALKER& Boys) except the former having an
opaque band around the inner margin of
the test.
Holotype :-Reg. No. CF. 3009, in tufaceous coarse sandstone at Loc. 11,

Takayasu UCHIO

38

type locality of Tomiya tufaceous sandstone (Tomiya, Takeoka-mura, Kimitsugun, Chiba-ken), 1000 m SWW of Kazusaminato Railway-station of West Boso
Line, (upper part of Tomiya tuffac~ous
sandstone, middle Pliocene). Length ca.
0.32 mm, width ca. 0.30 mm.

also found out throughout upper Pliocene
and Plio- Pleistocene Formations of B5s5
Peninsula, Chiba-ken.

Occun·ence and geological age :-Not

Genotype, PseudaePonides japonicus UCHIO

rare at type-locality above mentioned
also found out throughout upper Pliocene
and Plio-Pleistocene Formations of BOso
Peninsula, Chiba-ken.
Remark:-The specific name is dedicated to Dr. ]. A. CUSHMA!S.

Entosolenia marginata var. a1tgulata
Ucmo, var. nov.
Plate 3, Figures 14 a, b.
Lagi!IUJ marginata var. CUSHMAN, 1933,

U.S. Nat. Mus., B11ll. 161, Pl. 4.
Figs. 11 a, b. P. 17

This new variety is also formerly described as E. nzarghzata by many authors,but ]. A. CusHMAN always described
this as E. margi1Zata (W. & B) var.
Variety quite resembles E. marginata
and E. margi1Zala var. cushmani, but
the periphery of this is exceedingly
thickened. Therefore apertaral view ofthis variety is elongate quadrangular.
Variety also easily distinguishable byhaving neither an opaque band nor thin
carina.
Holotype :-Reg. NO. CF. 3010 in tufaceous coarse sand-stone at Loc. 11,
type-locality of Tomiya tufaceous sandstone (Torniya, Takeoka-mura, Kimitsugun. Chiba-ken), 1000 m SWW of Kazusaminato Railway-station of West Bos5
Line (upper part of Tomiya tafaceous
sandstone, upper Pliocene). Length ca.
0.31 mm, width ca. 0.28 mm.

Occnrrence a1Zd geological age :-Notrare at type-locality above mentioned,....

Family Rotaliidae
Genus PseudoePonides Uclllo, 1950

Test trochoid, biconvex, umbilical area
closed: wall calcareous, finely perforate :chambers numerous, all visible from thedorsal side, only those of the last-formed
whorl visible from the ventral side :aperture a low opening between the
periphery and umbilical area, usuallywell away from the peripheral margin,
with supplementary apertures loop·
shaped opening along each suture radiating from the umbilicus ventrally andalso elongate slit in each chamber parallel to each suture dorsally.
This new genus is closely allied toMississiPPina HowE, 1930 in respect ofaperture and supplementary apertures
but the aperture of the latter extending
to the periphery, that of the former wellaway from the periphery, moreover thedorsal supplementary apertures of thelatter elongate slits near the periphery,
those of the former loop-shaped, radiatingfrom umbilicus. This new genus alsoquite resembles Eponides MoxTFORT,
1808 respecting outline of the test, but
the latter has no supplemcntery apertures. Judging from the structure of
the test and aperture, this new genus
may derive from EPistomi1za TERQUEM,
1883.

Pseudoepottides japonicus Vcuw
Plate 3, Figures 1 a-c

PseudoePonides japonica Ucuro; ]oum.
Assoc. Petro. Tech. Vol. 15, No. 4,1950, P. 190, Fig. 16 (in Japanese).

Description :-Test trochid, biconvex,

New Species and Genus of the Foraminifera of the Cenozoic Formations

close-coiled, peripheral margin rounded,sutures depressed on both sides, strongly
oblique to spiral suture dorsally, shapeof chamber nearly triangular ; aperturea low opening between the peripheryand umbilical area, well away from theperipheral margin, with snpplementary
apertures loop-shaped opening along suture radiating from umbilicus ventrally
and also elongate slit in each chamberparallel to each suture dorsally.
Holotype :-Reg. No. CF 3002 in sandy
mudstone beneath Ka1 Tuff, along
Otaki-ChOnan High Way, beside thebridge, 200 metres southeast of Primary
Scholl, Satsubo, Nishi-mura, Chosei·gun.
Chiba-ken Japan. Length ca. 0.30 mm,
thickness ca. 0.17 mm (Kakinokidai Formation, Plio-Pleistocene)
Associated faunule :-Except Globigerinidae, Gaudryina cf. ishikicnsis AsANovery abundant, Cassidulina subglobosa
BRADY, Bulimina aculeata u'ORBJG~Y
and Pseudoeponides japonicus are also
common.
Occurrence :-In Biisf• Peninsula, Chiba
Pref, this new species is hitherto foundin Kokumoto Formation (upper Pliocene)
Kakinokidai Formation (Plio-Pleistocene)
and Sanuki Formation (Plio-Pleistocene).
Remark :-After the writer described
Mr. Y. KuwAl\0 also described thisspecies under the name " EPistomaria(EPistomariella) miurensis n. subgen. et
n. sp. " in article entitled " Foraminiferafrom the Pliocene Formations of Tama
Hills", jour. Geol. Soc. japan, vol. 56,
No. 657, 1950.

39

Description :-Test much compressed,
ovate, superior surface slightly convex.
inferior concave; periphery rounded;sutures and margin on superior surface
limbate; chambers comparatively few,
about 4-6 in last whorl, enlarging rapidly,
slightly inflated ; whorl 1.5 ; aperture astrongly arched slit situated in a depression on the inferior surface of the lastchamber, and is visible as small roundbeads along each septal suture on the
superior surface ; shell very finely polished, many radially depressed striationon the inferior surface.
Holotype :-Reg. No, CF 3008, in mudstone beneath 0 2 Tuff Loc. I-476,
Nakano,Kamitaki-mura,
Isumi-gun.
Chiba· ken (Lower part of Umegase
Formation, upper Pliocene). Length ca.
0.37 mm width ca. 0.29 mm.
Comparisilm :-This new form resembles H. (?) Ungulata (BuRRows & Hor.LA:-:o) shown in BRADY's Challenger
Report (Pl. XCI. Fig 3, not 2, p. 653,
under the specific name "Discorbina
bico11cava PARJ.;ER & Jot-:ES ") in its
superior surface but is quite different ininterior surface.
Occurrence and geological age :-Rarein "Umegase" and "Kokumoto" For·rnations both upper Pliocene.
Remark :-The specific name is dedicated to late Dr. Yanosuke 0TUKA,
Profes.c;or of Geological Institute of Tokyo
University.
Family Cassidulinidae
Genus Cassidttlina n'ORBJG~Y, 1826

Genus Herottallenia CHAPMAN &Genotype, Discorbina wilsoni HERON-Ar.r.E~
et EARLA!':D

Genotype: Cassidulina laet:igata n'ORBIG:-.'Y,
Amt. Sci. Nat., Vol. 7, 1826, p. 292. Pl.
15, Figs. 4. 5. model No. 41 : recent sandfrom ship's ballast.

Heronallenia otukai Ucmo, sp nov.

Cassidulina asanoi UcHio

Plate 3, Figures 5 a, b.

Plate 3, Figures 2 a, b.

PARR,

1931

Takayasu UCIIIO

40

Cassidulina asanoi UCHio, ]our. Assoc.
Petrol. Tech., 1950, Vol. 15, No. 4.
P. 190, Fiy. 13 (in Japanese)

Description :-Test compressed, nearlycircular in side view, lenticular in edge
view; chambers distinct, elongate, 4 pairs
in last-formed coil ; sutures distinct, depressed, much curved; wall smooth,hyaline, transparent : periphery angledwith thin carina; aperture a very longslit along suture of last chamber. Diame·ter ca. 0.29 mm, thichness ca. 0.10 mm.
Holotype :-Reg. No. CF 3003, in sandy
mudstone beneath Kus13 Tuff at Loc.
753, Oyagi, Tsuchimutsu-mura, Chosei·
gun, Chiba-ken (Lower part of Kokumoto
Formation, upper Pliocene).
Comparision :-This species formerly
determined as C. laevigata n'ORBIGNY
by K. AsA:-<o. The writer obtained many
specimens of this new fom1 from type
locality but non of them resemble
ll'ORBIGNY's original figure which is theschematic model figure of specimen fromship's ballast, the source of which is
unknown. K. AsANO figured two typesof C. laevigata (?), namely Text-figs. 11
a, b, and Plate XII, Figs. 4 a, b in his
paper entitled " On the Japanese Speciesof Cassidutina, 1apan. 1our. Geol. Geogr.
Vol. XIV, Nos. 2-3, 1937" but they are
different from one another and the latteris the writer's new from.
Occurrence

andgeological

Descnption :-Test compressed, nearlycircular in side view, lenticular in edgeview, periphery angled with thin carina ;chambers distinct, short, triangular,
4 pairs in last-formed coil, sutures
distinct, neary straight slightly depres
sed : wall smooth, hyaline, transparent,
particularly in umbonal region where
earlier chambers and proloculus arevisible; aperture elongate, nearly paral·
lel to axis of coiling.
Holotype :-Reg. No. CF 3004 fromsandy mudstone at Loc. II-218, southern
entrance of Odoro Tunnel, Kamitaki·
mura, Isumi-gun, Chiba-ken (Uppermost
part of Umegase Formation, upper
Pliocene) Diameter ca. 0.31 mm., thichness ca. 0.10 mm.
ComParision :-This new form is closely
allied to C. yabei AsANo & NAKAMURA,
but the chambers of the former short,nearly triangular, 4 pairs in last coil,those of the latter elongate, somewhat
quadrangular, 5-6 pairs in last coil ;aperture of the former is shorter thanthat of the latter.
Occurreuce and geological age :-Fairly
common at type-locality above mentioned,
also found throught out upper Pliocene
and Pleistocene Formationsof Boso Peninsula.
Remark :-The specific name is dedicated to Mr. Masayoshi NAKAMURA.

age:-

Abundant at type locality above mentioned and fairly common in Upper
Pliocene formation of Boso Peninsula.
Remark:-The specific name is dedicated to Dr. Kiyoshi AsANo, AssistantProfessor of Tohoku University, Sendai.

Cassidulina tzakamurai Ucuro
Plate 3, Figures 4 a, b.

Cassidulina nakamurai UcHio, ]our. Assoc.
Petrol. Tech., 1950, Vol. 15, No. 4,
P. 190, Fig. 14. (in Japanese)

Cassidzelina tomiyemis Ucmo,
sp nov.
Plate 3, Figures 3 a, b.

Description :-Test somewhat compressed, ovate in side view; chambers
distinct, 6 pairs in last coil, much inflated
but suddenly depressed near margin.
Comparision :-This new form resembles C. orientele in its out-line of thetest and aperture, but the former has
much inflated chambers which are de-New Species and Genus of the Foraminifera of th! Co:nn)i= F Jrm 1tions

pressed suddenly near margin showing
peculiar edge view.
Holotype :-Reg. No. CF 3011 in tufaceous coarse sandstone at Loc. 11,
type-locality of Tomiya tufaceous sandstone (Tomiya, Takeoka-mura, KimitSu·
gun, Chiba-kenJ, 1000 m SWW of Kazusaminato Railway-stat:on of West Bos5
Line (Upper part of Tomiya tufaceous
sandstone upper Pliocene). Length ca.
0.46 mm, width ca. 0.37 mm, thickness
ca. 0.2702 mm.

Occurrence and geological age :-Notrare at type-locality above mentioned,
but rare in " Sanuki " and .. Kasamori "Formations.
Family Anomalinidae
Genas Vagocibicides FI!'LAY, 1939

parent ; aperture in the early stages asin Cibicides, in adult rounded with ashort neck and a lip along outer growingedge of the last chamber.
Ho/otype :-Reg. No. CF 3015, in tuf·
aceous coarse sandstone at Loc. ll,
type-locality of Tomiya tufaceous sand·stone (Tomiya, Takeoka-mura, Kimitsugun, Chiba-kenJ, 1000 m. SWW of Kazusaminata Railway-station on West Boso
Line (Upper part of Tom:ya tufaceous
sandstone, upper Pliocene). Length ca.
0.62 mm, width ca. U.21 mm.
Occurrence tmd geological age :-Rareat type-locality above mentioned, upper
Pliocene. Cassidulina kazusaensis AsANo& NAKAMURA is the dominant species
associated with Vagocibici'des 1ziPPo11icus
UcHio.

Genotype, Vagocibicides maoria FI~LA Y

Vagocibicides mpponicus UcHIO,
sp. nov.
Plate 3, Figures 8 a, b.

Description:-Test plano-convex, elongate, dorsal side flattened or slightly
concave, early stages similar to Cibicides,
followed by several biserial chambers
and finally uniserial, uncoiling, expanding
somewhat as chembers are added ; sutures depressed ventrally and limbate
dorsally ; wail calcareous, rather coarsely
perforate, dorsal side somewhat trans-

41

References
K. KAWAI, T. UCHIO, etc.; 1950. '·NaturalGas in the Vicinity of Otaki, Chiba-ken ",]our. Assoc. Petrol. Tech. Vol. 15, No.
4. (in Japanese).
2. Y. QTUKA; 1949. " Fossil l\1ollusca andRocks of The Kiyosumi Group exposed
at Minato-machi, Chiba Prefecture andits Environs, (Ist Paper) •· Japau. ]our.
Gcol. Geogr., Vol. XXI, 1-4.
3 T. UCHio; 1951, "Foraminiferal study ofTertiary Formations near Otaki Gas
Field, Chiba Prefectures··. ]our. Geo/. Soc.
Japan. Vol. 57, No. 664. (in Jap:mese).
1.

42Takayasu Ucmo

Expanation of Plate
Figs. la-c.
Figs. 2a. b.
Figs. 3a. b.
Figs. 4a, b.
Figs. 5a, b.
Figs. 6a-c.
Figs. 7a, b.
Figs. Sa, b.
Figs. 9a, b.
Figs. lOa, b.
Figs. lla, b.
Figs. 12a, b.
Figs. 13a, b.
Figs. 14a, b.

Pseudeeprmides jaPonicus ucmo (Holotype) X 86.
Cassiduli11a asanoi Ucmo (Holotype) x 98.
Cassidulino tomiyaensis UCH!o, sp. nov. (Holotype) x 62.
Cassiduli11a nakanmrai UcHJo (Holotype) x 89.
Heronal/enia otukai Ucmo, sp. nov. (Holotype) x 82.
Lo:xostomum koikei Ucmo. sp. nov. (Holotype) x 45.
Bolivina otuka UCH!o, sp. nov. (Holotype) x 65.
Vagocibicides nipponicus ucmo, sp. nov. (Holotype) X 59.
Pyrgo dePressa var. tomiyaensis UcHio, var. nov. (Holotype) x48.
Enlasolenia ozawai UCH!o, sp. nov. (HoJotype) x 164.
Entosole11ia circulo-costa var. cari11ata UCIIIO, var. nov. (Holotype) x 125.
Entosolenia marginata var. semistriata UCHIO, var. nov. (Holotype) x 148.
E11tasolenia marginata var. CI4Simwni Uclllo, var. nov. (Holotype) x 91.
Entosolenia margi1wla var. angulata Uci!IO, var. nov. (Holotype) x 84.

Pt.ATE 3

Ucii! No, Cenozoic Forminifera from Chiba-kcn

Ia

2b

3n

3b

lb

53

6c

4a

5b

4b

7b

7a

Sa

Sb

6n

6b

9n

12b

lOa

lin

llb
lOb

13a

14n

Trans. Proc. Palaeont. S:>c. Jap:m N.S., No. 2 pp. 43-48, 2 text-figs. June. 1951.

198. NOTES ON THE ENTOMONOT/S-BEARING TRIASSICFORMATION AT IW AI NEAR ITSUKAICHI, TOKYO
PREFECTURE WITH A DESCRIPTION OF A
NEW ENTOMONOTIS.*>by

KOICHIRO ICHIKAWA
Osaka City University

JltJ?.~~::n:r:ntiilrW.'iHf~.t61t o $' Entomo~zotis lfi~-::>v•"C, lift Entomotzotis -;tJjffivililfG:!tJ-;Jfv$' E11iomo11oiis JB-v*.~H:¥ai!r L-. ~~ J:~lJ:ill!ID Iii] -&J!.ft<T.)JUl ~J!ttlf~.t611" o *lii<Di'ti~!. v
J.tfiU:rr-::>k 0 Entomonotis l.t!liJ:I".:t.ttl:ftV:!fJ-&-17) J:? r-:1t;fil;t~ ~ L- "CI.t_m l-~v'o -t"t.l:b"!>.
m.!~}~v:lfliMII!JlD:f!lif!-t"o c.!. ~~ L "Lit· o o -'-· Entom0110tis 4HIVJJI.~Uli~t.i:~tli~IJ=r-: t~lfU•ml> btl. o D:, LtJ> L, :kll-t"tt.~. ~ O~i!iv-A!ltMJ ltOO -.:.e. o c. !. Hli~ t... tc o ~r-:.

*Mf€v-~fill Entom01zotis iwaie11Sis <alioll&5:rr~ito

ililllifli-~

Triassic fossil localities of different
ages have been discovered within the
distance of several tens of meters fromthat locality, i. e., marl bearing blackshale formationll with Early Triassic
Ophiceras (FuJIMoTo, 1926; SHIMIZu,
1932), limestone bearing sandstone formation2> with Brachiopods and Pelecypods(CHoH, 1939), Late Triassic (Sakawan)(IcHIKAWA, 1950a) tine sandstone mem·her including Halobia molzekkana WAN·
KER
and Tri'gotmcula cfr. sakawanalcHII<A wA etc. and white sandstone v,;thMyop/zoria (Kuno, 1946; IcHIKAWA and
Kuno, 1951). The complicated geologic
structure has recently been investigatedby Kuno and the writer, and the present

During the study on the Late Triassic
Saragai group in the Kitakami Mountain·
land, the writer found the interesting
stratigraphical succession of variou;;
species of Entonwtwtis (lcH IKA w A l950b ).
In order to ascertain whether the succession is the local one confined to the
Kitakami Mountainland or the more
extensive one, the writer took up the
Entomotwtis-bearing formation at lwai
for study, which is located nearest to
the former. The result is presented inthis paper together with the descriptionof a new species of Entomotzotis.
Before proceeding further, the writer
expresses his sincere thanks to Prof. T.
KoBAYASHI for his encouragement invarious ways; he is also very gratefulto Mr. A. Kuoo for collaborating thegeneral field survey of the Itsukaichi
region.

* Read: Sept. 20, 195(); received: Nov. 10,1950. This is a result of the study tnade
by the research grant from the Education
Department.
1) named as Iwai formation by ICHIKAWA
and KUDO (1951).
2) named as Arai formation by ICHIKAWA
and KUDO (1951).

1. Geological Notes
Since " Pseudonwt:otis " was reported
from Iwai by FuJI:o.IOTo (1926), several
43

Koichiro lCIIIKA WA

44

1>urvey is summarized in the " Triassic
System of Japan " (1951).
As shown in the geological map,
Entomottotis-bearing formation forms anarrow " Schuppe ", thrusting over the
Ophiceras-bearing formation (lwai formation) to the west and thrust by thefusulinids bearing Palaeozoic chert andlimestone formation from the eastside
and itself forms an anticline with the ge:
neral axis of N 10°-60° W, 35°-70° WorE.
In the western wing there lies the
limestone bearing sandstone formation
with Brachiopods and Pelecypods (Araiformation) to the west of the present
formation in the same trend, but they
may be separated from each other bya fault. At any rate, the exact strati·
graphical relation between the two is
unknown.
The Entomouotis-bearing formation iscomposed of dark greenish fine sandstone,
micaceous sandstone and black shale, andat least 30m thick along the M-valley(see geological map), where it is best
exposed.
2.

Mode of occurrence ofEntomonotis
Loc. 50 KI-6 is the famous fossil local·
ity along the valley and belongs to thewestern wing of the anticline. Here thefollowing succession of each species of
Etzlomotzotis can be observed in discending order.

Joe. 6b,thickness in meterz. p inclusive (boulder)6
d 50. o 25, a 25
6.5
d 74, 0 2630
d 5, o 20, e 30, a 35, p 10
l.R
0.8
d 14, o 29, e 29. a 28
0.5

Joe. 6a,i 100

Joe. 6e.
Joe. 6d.
Joe. 6c.
Joe. 6b,O.R

22
Notes:- Abbreviation ; z- E11tomonotis zabaikalica, P· E. pachypleura, O· E. ochotica, d·

E. ochotica var. densistriata, e- E. ochotica
var. eurochis, a- E. ambigua, i- E. iwaiemis(nov.) The figure !.hows the individual
percentage of each species at each locality.
The calculation is based upon 150 individuals
for Joe. 6a-6c where fossils are abundant,
and 20 individuals for Joe. 6d where theyoccur in a limited p!ane of stratification.
The optional sampling is more or lessrestricted in the case of Older Mesozoic
megafossils. since only such parts of exposure
where fossils are well pr('served and easilycollectible must be sought for the specificar.d infraspecific identification. but the writer
tried to collect from as many scattered partsas possible within one bed.

Beside this, d 100 is calculated at loc.
11 about ten and several meters below
loc. 2a, but it is not yet certain whether
loc. 11 lies truely below Joe. 2a or not,since dip and strike is not known of theformer locality. Fossils are rather rarein other parts of the western wing. In
the eastern wing Entomonotis is veryrare and there is no locality where fossils occur so abundantly as in loc. 6.
At Joe. 50 KI-10 (a cliff behind a house)to the south near Tensho-ji, Entomonotis
occurs abundantly and e 49, p 23, o 20, d
6, a 2 is calculated from 150 individuals.
From these observations following
statements are available, namely1) At Iwai the member with abundantfossils merges laterally with the member
with few fossils and there is no clear
fossil zone3 1 as seen in the Saragai group.
In other words the occurrence belongs to
the kind of fossil enclosure (IJIRI and
Ft:JITA, 1949). This must be due to thedifference of sedimentary environment3) The term ··fossil zone" is here used as
the member or bed (formational unit)chancteriscd by the occurrence of acertain species or a certain assemblage ofseveral species.

Notes on the Entomonotis-bearing Triassic Formation at Iwai near ltsukaichi

between the contemporaneous Saragai
group and the present formation.
2) It may be immature to attempt
the general consideration on the mutual
relation between the fossil occurrence
and the sedimentary (and paleoecological) environment, since the mode oflamination and bedding cannot well beobserved due to the bad exposure, andthe lateral change of strata as well asof fossil occurrence cannot satisfactorily
be pursued owing to the complicatedgeologic structure. But the above cited
succession of Etzlomonotis at locs. 6a-e
where fossils are found most abundantly
within the formation can hardly beoverlooked. In the remain;ng localities,
on the contrary, fossils occur neither
abundantly nor successively and theirstratigraphical occurrences do not essentially disturb the succession at Jocs. 6ae. Therefore the general fossil succession within the present formation may
approximately be stated in ascendingorder as foJlows:(1) i 100 (represented by Joe. 6a), (2)common occurrence of d, o, e, a, (p)(chiefly represented by Jocs. 6b-6d), (3)appearence of z (represented by Joe. 6e).
If Joe. 11 ( d 1()()) is really located below
Joe. 6a, the general tendency of specificoccurrence is nearly the same as in the
Saragai group.4>
The following three differences can,however, be pointed out, namely1) Ettlomonotis iwai(msis which occurs
exclusively in Joe. 6a, is not met with in
the Saragai group.
2) At Iwai E. pachypleura appears
already in the part where d, o, e, and aoccur abundantly, whereas in the Saragai
group it does not yet appear in E.
ochotica zone where d, o, e, and a occur
commonly.
3) In the Saragai group E. pachyPlettra zone characterized by the domi-

45

nance of pachypleura and eurachis exists
between E. ochotica zone and E. zabaikalica ?..one. Such a part is not observed at
Joe. 6.
The writer interpretes these differences
as follows:(1) E. iu.JaietJSis (nov.) is an uniquespecies different from ochotica and its
allies in some respects as shown later,
and probably belongs to other •evolution·
ary series of Entomonotis than ochotica
series (temtissima, typica, ochotica v.

densistriata, ochotica, pachypleura, zabaikalica) which can be pursued in the
Saragai group.
This species occurs
exclusively in Joe. 6a, and not in otherlocalities, and must be an accidental
element.
(2) The specific assemblage of E.
pachypleura zone in the Saragai groupis represented at Iwai in Joe. 10, althoughpachypleura is not the dominant element]~ere. Its absence in the profile at Joe. 6
may be accidental since the typical fossil
zone is not developed at Iwai. Earlier
appearence of pachyplettra at Iwai showsthat the phenomena of the specific succession in the Saragai group is not always
applied directly to other districts.
3.

Summary

Finally it may ·be concluded that thegeneral evolutionary trend of Entomonotis appears similar in the Kitakami
4) In the upper formation of the Saragai
group following fossil zones are recognized by
the writer (1950b) in ascending order(1) E. typic a zone ( t- 30-40%, d- 60-70%)(2) E. ochotic:J v. densistriata zone (d100%).
(3) E. ochotica zone (o· 25-45%. d- 2535?o. a- 20-45%. e· 1(}-25%).
(4) E. pachypleura zone (p- 50-70%, e25-45%. o. a, d a little).
(5) E. zabaikalica zone (z- 95%. p, e. o. d
5%).

Koichiro ICHIKAWA

46

Mountainland and Iwai, although phenomena of specific succession are not quite
the same, because of the difference ofthe sedimentary environment. At Iwai
early representatives such as E. tenuis·
sima and E. typica are not yet found,and further E. iwaiensis appears as an
exotic member before the stage of common occurrence of d, o, e and a.
4.

Description of species

Genus Entomoiwtis MARWICK, 1935
Reference:- Entamcmotis KallA\' ASH! andlCHIKA WA, 1949. p. 2-!8.

Genotype :-Jl!onotis salinaria var. richmotl·
diana ZITTEL.

Eutomonotis iwaiensis IcHIKAWA,
new species
Text-figures 1-2.

DescriPtion: Shell comparatively small
for the genus, inequilateral, a little
longer than high, postero-ventrally elon·
gated. Left valve rather strongly infl·
ated, the maximum inflation lying at
about mid-height ; anterior margin round·ed up to the dorsal margin, ventral
margin broadly arcuate, posterior margin
strongly convex, the posterior extremity
lying at about umbonal two-thirds of theheight ; hinge-line straight and short,about half as long as the maximum
length ; the posterior wing ill-definedand obtusely truncated behind. Umboof moderate size, lying at about anterior
two-fifths of the shell-length, much rising
above and overlapping the hinge-line,
and strongly incurved. Surface covered
v.ith fine, distinct, and comparatively
regular ribs which count about 40 in theholotype, 20 mm long, and become finerin the postero-dorsal area ; ribs of second
order rather rare, initiated near thebeak and becoming nearly as strong as
the primary in later stage; concentric

growth striae rather faint.
Measurement: The holotype (MM5369>. a left valve, is 18.5 mm high, 20
mm long and 6 mm thick, while theparatype left valve (MM 5370) is 20
mm high, 22 mm long and 8 mm thick.
Observation:
Judging from many
topotypes, the umbo of the holotype isa little more slender than usual and thegeneral outrne and convexity is better
manifested in the para type (MM 5370)(Text-figs. 2a-c). The ribs of the latter, however, is indistinct owing to thebad state of preservation. Althoughseveral ribs of second order are observedin the holotype, they are generally rarein many other topotype. In some specimens ribs are rather densely set, but insome others they are rather broadly
spaced.
Compariso1Z : E. iwaieusis resembles
a specimen (MM 5274) from Takenotani of the Sakawa Basin, Shikoku which
was once referred to E. multistriata
KoBA v ASH! and lcHJKA WA (1949, p. 255,
pl. 9, fig. 14) in the more or less strong
inflation, general outline, and generalmode of ribbing, but the ribs are more
slender and densely set and the ratio oflengt;h to the height is a little smallerin the former than in the latter. The
present writer now thinks that the•· multist1·iata" from Takenotani (op.
cit.) is more akin to E. tem1icostata var.
mabara KoBAYASHI and lc11IKAWA (1949,
p. 26'), pl. 9, fig. 8) from the same
locality than to E. multt'striata,sJ although
5) When the author examined the •· ·multistriata" from Takenotani (op. cit.), he was
influenced by the fact that it is conspecificwith a specimen from Umenokidani which wasregarded as the topotype of nmltistriata Kos.
and lCIIIK. But it may not be so, since it is
not certain whether the locality Umenokidani(47TK-25) is exactly represented by one
exposure or not.

Notes on the Entom01zotis-bearing Triassic Formation at Iwai near Itsukaichi

2c

47

2a
2b

Entomonotis iwaietzsis IcHIKAWA, sp. nov.

Figs. la-c. Internal mould of the left valve, the holotype.
a. front view; b. dorsal view ; c. anterior view. x 2.
(Reg. No. 11:\1 5369).
Figs. 2a-c. Internal mould of the left valve, the paratype.
a. front view; b. dorsal view; c. anterior yjew. x2.
(Reg. l'o. MM 5370).
(Both specimens are now kept in the Geological Institute, University of Tokyo.)-

Geological Map
of
Iwai, near Itsukaichi(K. Ichikawa, 1950).....

~ Itsukaichi group (Tertiary)\wai.

E::l Arai formation with

1:::..::.3

Brachiopods and Pelecypods

CIJ

Entomonotis- bearing formation(Late Triassic)
Halobia-bearing formation(Late Triassic)
Iwai formation with Ophiceras(Early Triassic)
Palaeozoic formation("Klippe")

~

[[[]

m

0

:zso

48

Koichiro ICHIKAWA

ribs of the second order are regularly
inserted and ratio of height to length issmaller in mabara.
In outline and especially in the ratioof height to length E. iwaieusis is intermediate between the "multistriata" from
Takenotani and temdcostata var. mabara.
In some specimens of iwaieusis the umbo
is prosogyrate as in the " multistriata ",but in some others it is like that inmabara, although the variation may be
due to the later deformation. In tenuicostata var. mabara ribs of the second
order are regularly inserted between
the primary ones, while ribs of thesecond order are rare in iwaiensis as intemticostata s. str., but the latter is diferent from the former in the stronger andbroader umbo and more densely set ribs.
Formation and locality :-Entom01zotis·
bearing formation at loc. 50 KI-6a, along
the M-valley at Iwai, near ltsukaichi,
Tokyo Prefecture (See geological map.)

References
CHoH, R., 1939, Some New Facts concerning
the Triassic Formation at Iwai near
Itsukaichi, Province of Musashi: ]our.
Geol. Soc. fapau, vol. 46, no. 546.
FUJIMOTO, H., 1926. A New Locality of
Pseudomonotis: ]ot4r. Geol. Soc Tokyo,
Vol. 33, tiO. 390.
]CIIIKAWA, K., 1950a, Chronological Classific.
ation of the Triassic Period in Japan;
jour. Geol. Soc. japan, vol. 56, no. 652.
- - 1950b. Saragai Group in the Kitakami
Mountainland, with special Reference toEntomono/is in it (Abstract)_: ]our. Geol.
Soc. japan, vol. 56, no. 656.
- - and A. Kuoo, MS. ··South-eastern Partof the Kwanto Mountainland" in "Triassic

System of Japan". To be published byGeological Survey of Japan.
lJIRI, S. a:-~d Y. FUJITA, 1949, Fos.>il Enclosure: Geologtcol Sciet~ce (The ]ouma/ of
the Association for the Geological Collaboration). no. 1.
KnBA YAS HI, T. and K. lCHIKA WA, 19,l9, Late
Triassic "Pseudomono/is" from the Sakawa
Basin in Shikoku, Jap.m: ]apo11. ]our.
Geol. Geogr .• vol. 21.
KUDo, A., 1946, Discovery of Halobio-bearing
Formation at lwai. near Itsukaichi, Province of Musashi; jour. Geol. Soc. Japan,
vol. 52, nos. 613-615.
SIIIMIZU, S., 1932, Lower Triassic Ammonites
from Iwai, Okuno-mura, Nishi· Tama-gun,Tokyo-fu: ]our. Geogr. Tokyo, vol. 44,
110. 516.
Manuscript completed in September lOth, 1950.
Postscript
S. W. MULLER in 1938 claimed that Ento·
monotis MARWICK must be synonymized with
Mono/is BRONN, because Monotis solinolio, thegenotype of Monotis, has a byssal notch on
the right valve like Entomonotis. KOBAYASHI
and IcHIKAWA (1949), however, hesit:lted touse Monotis instead of Entomonotis by thereason that, even if the right valve of Mono/is
has the byssal notch, Entomo11otis is m:trkedly
inequivalve, while Monotis is said to b.: equivalve, of which point MULLER gave no mention in 1938. In reply to the quesion Prof.
MULLER kindly communicated with the writerin a letter dated February 12, 1951 that thesp~cimens of Mono/is s1linolio, which he collected in the type locality in the Tyrolian
Alps, contained both the equivalve as well as
the inequivalve individuals. Although the present writer has not ex:~mined the specimens of
Monotis so!inalio, Mono/is might be used forthe group of " Pseudomonotis" ochotica infuture.

Trans. Proc. Palaeont. Soc. Japan N.S. No. 2, pp. 49-56, 2 text-figs. Jan. 1951.

199. ON THE MYOPHORIANS FROM KYOTO PREFECTURE(PROV. Tango).UNOBUKAZU KAMBE
Geological Survey of Japan.

Jil:ftllltf!l MyoPhoria tf!Kf,t"C: 1947 .If..& 1948 &f.r.:.!H•Jil:ml!&Jmi£Jlf>.lt!!.tf<7;Ttf/J;¥(l(JJW~i8!..tlil;;1.!iJtn~iilili!frml (i!¥f.&!'J;¥i ~.=E~ 'T) li· b 1/J~'ft:OIH ftJl. L"ko ;<f>;iJJ.Wf~~l'l~jllj1it~1t:OtH.lt'ToM1$J: !lrtbH,~Too ..t~C.l!l~ft:OI$t;t 1 em I'!M-<7)~~r.:'J'~"·.=.;&

Jlllf(-c: Myophoria 6 spp., Gervilfia spp., Nucula? spp . .1: !lt.l:o 0 4'.Yr.:lflfft~<7;~gft~t.l:-::>k
MyoPhoria ~fili.&tnlf£'/lli/ii.JV!i#{l}JIE,J•.IJ&~~ri&»-bi$.Lk Myophoria -f!liHcl2To 0lil;;jW;~:

1. Jlffyophoria tangoensis KAMBE, new species.
2. Jlffyophoria shidakmsis KAMBE, new species.
3. Myophoria a; sp. nov. indet. (aff. M. laevigata v. ALBERTI in SCHMIDT)4. Myophoria ~ sp. nov. indet. by KoBAYASHI and ICHIKAWA, 1949.
5. Cfr. Myophoria laevigata (ZIETHEN) var. el011gata PHIL.
6. Cfr. Myop}zoria laevigata (ZIETHEN) var. rotunda PHIL.
~ilf.~:

7. Myophoria goldfussi v. ALBERTI var. kobayashii KAMBE, new variety.
lil;;,\':i~ MyoPhoria ~f!lil;ttf_....:.-c E. RtiBENSTRU:-;K r.: J: o "Glatten Myophorien Gruppe"r.:~ L, ~j!J:~ Myophoria -f!lil;t "Vie!rippigen Myophorien Gruppe" rt:~T o o;r.;,j\':j/!ifn<7;1J#ftl;t Myophoria ~flit~ ;;!;j',';)t!ftlf!.l1i:..Otfr.: J: -::><: Upper Camic·Noric <7) 1 na;l!ll
H~illUL-"ko ~.JI.EMt~Jii.,t"C Myophoria fil!»·b!J'IJ}E~.tt.olflioftf;t Ladinic ]}~Carnic -c:hooj!Jr}'iftillJ

Zamites megaphyllus
Taeniopteris
stenophylla
KRYSHT., T. sht'takaensis OisHI, Czekattowskia sp., Podozamites griesbachi SEWARD
and P. lattceolatus (L. & H.).

0. & T.,The coal-bearing formation at Shidaka,
6 km. west of Maizuru, which OcA w A
denominated "Shidaka series", in 1897,
yields plants. For the age of this flora
Upper Jurassic was suggested by TAKAHASI!I, 1915, Jurassic by YABE, 1922,
Middle Jurassic by OisHI, 1932 and at
length Liassic by KoBAYASHI, 1938.
Although none of the Dipteridaceae wasfound, OisHI, 1940, has referred it tohis Dictyophyllmn series. It comprises
CladoPhlebis nebbensis (BRoNGN.), C.
denticulata (BRoNGN), C. haiburnensi's(L. & H.), C. Raciborskii forma integra

Cfr.

(PHILLIPS),

Because the Shidaka area used tobelong to the strategic zone, no pnc1se
investigation was done in the stratigraphy of the above mentioned formation. Lately I have carried out its survey and as a result a faunule was discovered near the top of the series, more
1) Received Jan. 20, 1951 ; read Dec. 2, 1950.
49

Nobukazu KAMBE

50

precisely, in the basal part of its top
division at Mirokudani of Shidaka,
Okadashimo·village, Kasa-gun, Kyoto
Prefecture, as the geology of the area
had already been reported in my former
paper. In this collection 6 species ofMyophort"a, beside indeterminable GervilJt"a, Nucula (?) and a few others, weredistinguished as follows :1. MyoPhoria tangoensis KAMBE, new species
2. MyoPhoria shidakensis KAMBE. new species
3. Myophorin :x sp. nov. indet. ( :~ff. M.
laevigata v. ALBERTI in SCHMIDT)
4. 1'vfyl'Phoria ~ sp. nov. indet. by KOBr\YASHI
and ICHIKAWA, 1949
5. Cfr. Myophoria laevigata (ZIETHE:-1) var.
elongata PHIL.
6.

Cfr. Myophoria lae~·igata (ZIETHE.t-;) var.
rotunda PHIL.

The profusion of Myophorians evidently indicates that the faunule must be
Triassic. instead of Jurassic. All ofthese species, however, belong to thelaevigata-group which is widely ranged
through the Triassic. M. laevigata is
distributed from Skytic to Noric and its
varieties, rotunda and elotzgata in Ladinic and from Skytic to Anisic respectively. M. shidakensis is similar to M.
laPvigata and so M. tangoensis to Upper
Tr·assic (?) M. timorensis. Myophoria(3 sp. nov. indet. is apparently allied tothe one from the Myoconcha sandstone
in the Sakawa basin in Kochi Prefecture(Prov. Tosa) which is late Carnic, if notearly Nor'c. Except the last one there
is none exactly identifiable with any
spPdes of known age.
For the chronological consideration,
however, it is noteworthy that theLower Carnic Nabae group in the same
region is strongly disturbed together
with the older formatwns (NAKAZA WA
and OKADA, 1949), while the Shidaka
which reveals the Molasse type of
sedimentation, lies unconformably O!J the

already contorted Palaeozoic formation.
Therefore the faunule in question must
be not older than Middle Carnic. But
at the same time it can be mentioned
from the aspect of the Myophorians thatthe age of the faunule must be notyounger than Noric, the conclusion being
upheld by the above listed flora, if one
notices the fact that the Rhaeto-Liassic
type of flora appears in Japan alreadyin the Carnic period (KoBAYASHI, 1939).
On this occasion Myophoria goldfussi
v. ALBERTI var. kobayashii KAMBE fromthe Guzyo format:on at Guzyo, Kawanishi-village, Kasa-gun is described.
Because the geologic structure there iscomplicate, its stratigraphic position
must be older than the Nabae (NAKA·
ZA WA, 1950). Because the known rangeof M. goldfussi is from Ladinic to Noric,
the age of the Guzyo fossil bed may beeither Carnic or Ladinic.
Here I wish to express my sincere
thanks to Prof. T. KoBAYASHI of the
University of Tokyo for his suggestionand guidance and also to Mr. K. IcmKA WA for the assistance in this palaeontological study.
Family Trigoniidae LAMARK
Genus llfyop!toria BRaN:-.~, 1827.
The genus has already been studied
by LYcETT (1879), WonRMANN (1893),
KoKEN (1896), WAAGEN (1907), RuBENS·
TRU!\K (1909), DIENER (1925), ScHMIDT(1928), FRANK (1929) CR!CKMAY (1932),
LEBKUCHNER (1932) and many others
and it is generally considered to be thelinking genus between Schizodus andTrigonia. RiisENs:rRUNK classified it into
five groups, namely Glatten Myophorien,
Einrippigen M., Zweirippigen M., Vielrippigen M., Konzentrisch skulpturierten
M.
In Japan Myophorians are reported toOn the Myophorions from Kyoto Prefecture (Prov. Tango)

occur in the Permian of Kinsyozan at
Akasaka, Gifu Pref. (Prov. Mino.) by
HAYASAKA (1925), Permian Kohama
limestone at Kohama, Monohu-gun in
the Kitakami mountainland by INAI an::!
TAKAHASHI (1940), early Triassic forma·tion at Kurotaki, in Kochi Pref. by
MATSUSHITA(1926), early Triassic
Hiraiso formation at Hiraiso sea-shore,
Motoyoshi·gun in the same mountainlan::lby MABUTI, Upper Triassic Kochigatani
series of the Sakawa basin in Shikoku
by KoBAYASHI and IcHIKAWA (1949),
Triassic (Ladinic or Carnic) Guzyo
formation at Guzyo, in Kyoto Pref.
(Prov. Tango) and the Triassic (Noricor Upper Carnic) Shidaka formation at
Shidaka in the same province both bymyself (1950), but only a part of them
are so far described.
The Shidaka
specimens are not well preserved, but a
few of them show the typical dentationof Myophoria.
Putting aside the Permian ones ofwhich the generic reference is not war·
ranted, all of them are Glatten Myophorien except one from Guzyo which
belongs to the group of Vielrippigen
Myophorien. Such a display of Glatten
Myophorien of laevigata group in theUpper Triassk of Japan is certainly
remarkable.
1.

51

the shell-length from the anterior extremity, prominent and provided with aprominent umbonal ridge ; area withweak radial striation ; surface smooth.
Figure 1 shows the hinge. The obliquely lined parts are projected in theinternal mould of the right valve andaccordingly correspond to 2b and 2a ofthe left valve and the sockets to 3b+ 1.
and 1 of the right valve. For theterminology of the dentation, see
LEBKUCHNER, 1932, p. 24, fig. 18.
An internal mould and an external
cast of a right valve is 6mm. high and
9mm. long; its apical angle 150° and theangle exclusive of the area 120°.

3b~.'~-~a.

/.f~
I
.
2b

1

Figure I. Sketch
showing the hingeof Myophoria
tangoc11sis.

Comparison :-This species is allied to(? ) M. timorensis KRUMBEcK (1924, p.

238, pl. 18, figs. 17-20) from the upper
Triassic of Timor, but more or less dif·ferent in the position of the umbo andcosta, the umbo being more projected in
the former than in the latter and thecosta less rounded in the former than in
the latter.
Occurrence :-Miroku-dani.

MyoPhoria tangoensis KAMBE,
new spec..ies.

2.

Myophoria shidakensis KAMBE,
new species.

Plate 4. Figures 1 a-b.
Pl. 4, Figs. 2 a-b.

DescriPtion :-Sheil small, inequilateral, subtrigonal, broader than high andconvex ; ventral margin broadly arcuate ;postero-ventral margin somewhat rounded; antero-ventral margin subangular ;posterior submarginal area broad andbordered anteriorly by a blunt costa;
umbo located at the point four-ninths of

Description :-Shell small, subtrigonal.
inequilateral, moderately convex ; postero·ventral margin abruptly rounded;
ventral margin arcuate ; anterior margin
nearly straight; posterior submarginal
area obtusely triangular and borderedanteriorly by a prominent and sub·

52

Nobukazu KAMBE

angulate costa; umbo located at aboutanterior one-third of the shell-length,
prominent and prosogyr, with an umbonat ridge in front of it ; surface smooth,with two or three concentric lines ofgrowth near the ventral margin ; posterior submarginal area smooth.
A left valve is 9 mm. high and 13 mm.
long; its apical angle 100° and theangle exclusive of the area 75° : denti·
tion not well known.
ComparisotZ :-This species is closely
allied to M laevi"gata in ScH:o.!loT (1928,
p. 183, fig. 421). The costa is, however,more broadly roof-shaped in the former.
It also resembles (? ) M. timore1tsis
KRUMHECK (1924, p. 238, pl. 18, figs. 1720), but differs from this Timor form in
the position of the umbo and the modeof the costa.
Occurrence :-Same as the preceding.
3. l'lfyophoria a sp. nov. indet.
pl. 4. Fig. 3.

Shell small, somewhat inequilateral,
trigonal, as high as long, inflated; posterior margin arcuate ; postero-ventral
margin imperfectly preserved but appears subangular; anterior margin nearly straight; ventral margin partly broken ; submarginal area vertical to theplane of junction between the two valves
and bordered anteriorly by a prominent
angular costa ; umbo prominent andlocated a little anterior to the midlength; area probably provided with aradial rib; umbonal ridge not observed;
surface probably smooth; dentition seen
as illustrated in figure 2 of the internalmould of the left valve. The obliquely
lined parts are the projections, corre·
sponcling to 1 and 3b+ 1 of the rightvalve and the sockets to 2b and thelateral teeth of the left valve.

An internal mould of a left valve is
13 mm. as long, as high ; its apical angle
90° and the angle exclusive of the area
80°.

Figure 2. Sketch
showing the hingeof Myophoria" sp. nov. indet.

Comarison :-This is more or lessallied to M. laevigata v. ALBERTI in
SCHMIDT (1928, p. 183, fig. 421), but dif·fers from the latter species in the aspectsof the costa, and the submarginal area.
The costa is arcuate and acutely angulated and the area provided with radialribs in the latter species.
Occurrence :-Same as the preceding.

4.

Myop/zoria (:J sp. nov. indet. by

KoBAYASHI and IcHIKAWA, 1949.
Pl. 4. Figs. 4a-b.
1949. Myophoria sp. nov. indet. KoBAYASHI.
& ICHIKAWA, ]oPatr. ]our. Ceo/. Geogr.
r:ol. 21, no. 1-4, p. 183, pl. VI. fig. 5.

The Shidaka specimens coincides with

Myophoria sp. nov. indet. from the
M:yoconcha sandstone at Umenokidani in
the Sakawa basin in most accounts,
notably in the costation and the positionof umbo. They are roundly subtrigonal,
very inequilateral, fairly well inflatened;
posterior submarginal area obtusely
triangular and bordered anteriorly by ablunt costa ; umbo located at the anterior two-fifths of the shell-length, prominent, pointed forward and delimited bya subvertical umbonal ridge anteriorly;
anterior margin short and straight ;On the Myophorions from Kyoto Prefecture (Prov. Tango)

test smooth. The ventral margin anddentition cannot be seen. As the dimensions are given below, the Shidaka specimens are smaller than those from
Sakawa. One right valve and two left
valves at hand.
Comparison :-This can be distinguished from Jv!yophoria a sp. nov.
indet. by the situation of the submarginal area, position of the umbo and thecostation and from M. sltidakensis by
the outline and costation.
1 right. valve(I)

I

left valve left valve
(II)
(lll)

-----,

heightI

lengthllrnm.

112mm.

7mrn.
8rnm.

lOmm.

weak radial rib in the middle part;surface smooth; dentition not clearlyobserved. An internal mould of a left
valve and an internal mould and external cast of a right valve give the following dimensions :--- - ---------': right valve(V)left valve(Vl)heightSmm.

9mm.

length

7rnm.

llmm.

apical angle

140°

140'

apical angle
exclusive of the, areall0°

110'llrnm.

apical angle 18oo

100°

1(0°

160~

70°

70°

apical angle
exclusiveof the area

53

I

Comparison :-Its close ally is !vi.
laevigata var. elongata PHIL. in ScHMIDT(1928), but owing to the incomplete stateof preservation any exact identification
is not admitted.
Occurrence :-Same as the preceding.

Occurrence :-Same as the preceding.
5. Cfr. Myophoria laevigata (ZIETHEN)
var. elongata PHIL.
PI. 4. Figs. 5 a-b.

1928. Cfr. MJoPhoria laevigata var. elongata,
SCHMIDT, Die Lebewelt Unserer Trias,
p. 185, fig. 425.

Shell small, elongated subtrigonal,
broader than high, very inequilateraland moderately convex; posterior margin
arcuate ; postero-ventral and anterior
margins not well seen ; posterior submarginal area large, elongate suboval
and bordered anteriorly by a prominent
angular costa ; umbo lying at about theanterior one-third of the shell-length,
prominent and provided with an umbonal ridge in front of it ; area having a

6. Cfr. Myop/toria laevigata (Zm·mEN)
var. rotunda PHIL.
Pl. 4. Figs. 6 a-b.

1928. Cfr. MyoPhoria laevigata var. rotunda,
SCHMIDT, Die Lebewelt Unserer Triasp. 183, fig. 423.

Shell small, broadly ovate, nearly
equilateral and somewhat inflated ; pos·terior, anterior and ventral margins wellrounded without any interruption among
them ; posterior submarginal area subtrigonal, depressed and bordered anteriorly by a prominent subangular costa-;umbo lying at the anterior threesevenths of the shell-length, prominent,with a somewhat oblique umbonal ridgein front of it; surface smooth; area ofthe left valve apparently possesses a

.,

56

Nobukazu KAMBE---- ---------------

Explanation of Plate 4Myophoria langoensis KAMBE, new species.
Fig. I a. Internal mould of the cotype ; right valve, x 2.
Loc. Miroku-dani.
Fig. lb. External cast of the cotype; right valve, x 2.
Loc. Miroku·dani.
MyoPhoria shidakensis KAMBE. new species.
Fig. 2a. Internal mould of the cotype; left valve, x 1.5.
Loc. Miroku-dani.
Fig. 2b. External cast of the cotype; left valve, x 1.5.
Loc. Miroku-dani.
MyoPhoria :x sp. nov. indet.
Fig. 3. Internal mould of the left valve, x 1.5.
Loc. Miroku-dani.
Myophoria ~ sp. nov. indet. by KOBAYASHI and ICHIKAWA, 19-!9.
Fig. 4a. Internal mould of the right valve. x 1.5.
Loc. Miroku.dani.
Fig. 4b. External cast of the right valve. x 1.5.
Loc. Miroku-dani.
Cfr. Myophoria /aevigata (ZIETHE!-<) var. elonga/a PHIL.
Fig. 5a. Inteanal mould of the right valve. x 3.
Loc. Miroku-dani.
Loc. Miroku-dani.
Fig. 5b. External cast of the right valve, x 2.
Cfr. MyoPhoria /aeviga/a (ZIETHEN) var. rotu11da PHIL.
Fig. 6a. Internal mould of th!> right valve, x 3.
Loc. Miroku-dani.
Fig. 6b. External cast of the right valve, x 3.
Loc. Miroku·dani.
M)•ophoria go/dfussi ALB. in BITTNER var. kobayashii KAMBE, new variety.
Fig. 7a. Internal mould of the cotype; right valve. x 1.5.
Loc. Guzyo,
Fig. 7h. External cast of the cotype; right valve, x 1.5.
Loc Guzyo.

All of these specimens are kept in the Geological Institute, University of Tokyo

KAMuF., Myophorians from Kyoto Prefecture

PI.ATJ! 4

Ia

2b

4n

lb

3

5b

Sa

4b

...

'~
.·.:.t\r~1;~l!'.iJ.; ...,.

.,.;....-.

t.l f ~ •.

~.f.,..

•' --..

6a

7a

6b

7b

Trans. Proc. Palaeont. Soc. Japan N.S .. No. 2. pp. 57-64, 3 text-figs. June. 1951.

200. PLIOCENE PINNIPED REMAINS FROM KANAZAWA,ISHIKAWA PREFECTURE, JAPAN."
YOSHIO KASENO
Kanazawa University, Kanazawa, hpan.
~~ili*~libt t- t-•1t:OK -?II• -c: ~il!itDI!~1::1/F.fftiiJ¥i'IBfifj7J">*~If J:$ J: ~ .1'-lfi L. 1: t- n1::;fiK-?..,•-clietlLko !!i:~E~!:ltl.!'tL1:::6;, -l:.fl.i>">fiiJtl.!: traJ5i!-t:tt.r:b>-?1:: 0 LtJ>Liffl!:
ToC.!:I;t<'!Ltl-:b>;t, ffii~ '·Allodesmus"sp. !:i!¥h..-t:~<o H.l!!fft7i;

INTRODUCTION

imperfect remains of molluscs as Acila,

The material described herein*, consisting of a right mandible and four
detached teeth of Pinnipedia, was collected- from the upper part of thePecten, Venericardia, Myodora. Cardium,
Diplodonta, etc. It seems probable thatthe remains of Pinnipedia and molluscs
were gathered up by waves and currents.

Figure A. Maps showing the lo::ality.

and entombed in the shallow sea bottom
to form a fossil bank.

Onma formation (Pliocene) at a roadcutting south of Gosyo village, northeastern end of Kanazawa City, Ishikawa
Prefecture, Japan. (Lat. 36" 3t' 4011 N. ;Long. 138° 41' 1011 E.) (Figure A.)
The locality where the present rna·terial occurred is composed of homogeneous silty fine-grained sandstone ofbluish colour. Together with the present material there were found many

1) Read March 17, 1951; received April 12.
1951.
• Now deposited in the Geological Institute,
College of Science, Kanazawa University,
Kanazawa. Jap:m.
*"In October, 1946, collected by the writerand the Third-year students of the Biological
Department, Kanazawa Higher Normal School.
57

58

Yoshio KASENO

In Japan the fossil remains of Tertiary
Pinrripedia have hitherto been reported
from the Upper Pliocene ( ? ) of Kazusa(MATsU:o.toTo, H. 1925, 1926) and from
the Middle Miocene ( ? ) of Shinano(NAGAo, T. 1941 ).* Thus the new occurrence seems to be of interest bothfrom geological and palaeontologicalstandpoints.
DESCRIPTioN(1) Right Mmzdible. (Figures C, 1, 3,
4.)

The horizontal ramus of the mandibleis almost complete, with the ascending
ramus broken off. The mandible isstrongly inflated and stout anteriorly,
with its maximum depth behind thecanine ; posteriorly it gradually becomes
low, being lowest slightly in front of theplane of coronoid. The horizontal ramus
is thickest in the anterior portion, andbecomes gradually thinner posteriorly.
The upper border of the horizontal
ramus is almost straight, the lower
strongly curved clown in the anterior
portion. Its outer surface is strongly
convex in its anterior portion, being
much flattened in the middle.
Innersurface is rather rlattened comparedwith the outer.
There are six distinct mental foramina
on the outer surface, nearly spherical or.
ellipsoidal in form, with the diametervarying from about 3 to 9. mm., thedepth from 2 to 4 mm. or more.
The symphysis is roundly triangularin outline, very stout and heavy, andnot ankylosed. The symphysial surface
is considerably corrugated and withseveral irregular grooves in the upper
portion, but rather smooth in the lower
half as far as observed.
Some measurements of the rightmandible are as follows:
Length of the preserved p:>rtion ....... 240 mm.
Distance between the posterior marginof the last molariform and theanterior margin of the canine....... 124 mm.
Distance between the anterior marginof the first molariform and theposterior margin of the last molariform ........................................... S~mm.
Maximum depth of the horizontal
ramus below the second molariform. 77 mm.
Maximum thickness of the horizontal
ramus .. . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . .. . . . 26 nun.
Maximum length of the symphsis....... 86 mm.

(2)

Detztitiotz. (Figures C, 1; 2a, b, c.)

The present right mandible has a large
canine and the second molariform tooth
attached, other teeth missing.
The dentition of the present species as
far as observed is as follows** :h!. Ia; Cr: LTr, LT2·. LTa. LT;r, LT11.
*Aside from several specimens which havebeen reported by Mr. N. NAORA. (NAORA, N.
1944).
** All molariform teeth are uniformly designated as "LT ", because there are no criterion
to distinguish the molar from the premolar.

Pliocene Pinniped Remains from Kanazawa, Ishikawa Prefecture, Jap:m

59

Dimensions of alveoli and intervals in between are given as foiiows:---------

h

1

Ih

Cr )LTr ILT1r ILT-s ILT;rjLTlf I' - - - - - - - - - - -.----~--'- - - _, · - '1 __ \Antero-posterior diameter of alveolus I,

I in upper margin of the mandible.

9

I

40

12

14

I

14 '

I

18

19

18

I

~~~- - - - - i - · --1------1-!--:--1
1

Transve~sal
di:lmeter of alveolus
perpendicular to the above. (mm)

I

5

I

9

29

I

I

12

12 I 10 I 10

I 10

'j'

I
~~mu~ depth of alveolus___ --~,-:--,--:-~-?-l~o-~--?-J-2-;l-:-1--;i(estJmate~(~m.) - - - ---11 __. Minimum interval between alveoli.
I (rnm.)i _1 ___...-i__l

1_ _ _, _ _ _ 1_ _ _ _

3

0

7

3

0

0

I

Incisors. Two incisors are missing,alveoli only being preserved. On examining the alveoli, the outer incisor(1-g) is large in size and subcircular incross-section, situated very closely to thecanine. The inner incisor (b) is muchsmaller in size, about one-half of theouter one, situated a little back of thelatter, sub-elliptical in cross-section withthe longest diameter parallel to thesymphysial surface. The alveolus of theinner incisor is strongly curved backward, which indicates that the innerincisor is directed forward at an angleof about 45 degrees.
Canine. Canine is situated very close
to the outer surface of the horizontal
ramus, large and bluntly conical, directed·
considerably outward, curved b:1ckward
toward the tip which is broken off. The
cross-section at the base of the crown is
sub-elliptic;1l in outline, elongated anteroposteriorly ; it is slightly smaller thanthe cross-section at the alveolus. Canine
is brownish in colour ; its surface is provided with numerous, crowded longitudinal wrinkles or ribs, directed from theapex to the base. The root is long,extending backward, and is penetrated
by the pulp hole which is circular incross-section. Dimensions are :Height of crown as pres~rved
45mrn.
Height of crown above ramus(estimated) ................................. 55 mm.
Anter;:>-po~terior diameter of bas:tl
section . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . 36 rom.
Transversal diameter perpendicular
to the above ................................. 31 rom.

Molariform series. Having only one
molariform tooth i1t situ, it is very diffi.
cult to give a full description of thisseries. There is scarcely a progressive
increase in size from the ftrst to thefifth: but the first and the second are
sub-circular in cross-section and nearly
equal in size, and more or less smaller
than the rest (the third to the fifth),
which are sub-elliptical in cross-section
and nearly equal in size.
The first and probably the second are
one-rooted and not grooved, alveolus of
the former being strongly curved backward at an angle of 45 degrees or lessto the ramus. The third as indicatedby the alveolus is very faintly grooved

60

Yoshio KASE!'iO

only on the outer side and is nearlystraight and almost vertical to theramus. The alveolus of the fourth isstrongly grooved outside and faintly
ins:de, and becomes two-rooted at theapex of root. The fifth distinctly bifurcates in the upper portion of the root,
the anterior branch being slightly smaller
than the posterior in cross-section ; bothare nearly straight and vertical.
The crown of the second molariform
tooth is low-conical, bluntly pointe:l atthe tip, sub-elliptical in cross-section,slightly elongatedantero-posteriorly.
One anterior and one indistinct posterior
accessory cusps are developed, and thelatter is larger in diameter than theformer. The second molariform tooth
has also a considerably well defined
cingulum, especially in the inner side,
on which a well defined peripheral cusp

tooth .......................................... 13mm.
Greatest height of the crown............ 9 mm.
Greatest width of tooth at cingulum ... 10 mm.

Detached Teeth. (Figures B, 1-4.)(3)

There are four detached teeth ofmolariform series which were obtained
together with the mandible describedabove. These seem to belong to thesame species and in all probability to thesame individual as the mandible. Here,
therefore, some of their morphologicalfeatures will be described, without assigning their original positions, andsimply numbering from 1 to 4.
No. 1 (Figures B, la, lb, lc.) has aconsiderably high, conical crown, bluntly
pointed at the tip, with one (posterior?) cusp, and with sharp cuttingedges. There develops a well defined

Dimensions of four molariform teeth are tabulated as below:
-

No.1

No.3

No.2

i

I

I Antero-posterior diameter in neck. (mm.)
-I

I

.

13
'

Transversal diameter in neck (mm.)

10

9

15.5

17

II
Width of tooth at cingulum. (mm.)

II Greatest height of crown. (mm.)

-----

13
--

-

!

Length of root. (mm.)

29+Ioccurs. (Figures C, 2a, b, c.) Measurements of the second molariform are as
follows:
Antero-posterior

diameter

of

the

17

9
14.5

---

-

---

12

13
--

10

10

11
---

13.5
---

I

-

--- -

12
I

I

i

8.5

-

-

I

i

I

-

I Antero-posterior length of crown. (mm.)
I

14.5

14

No.4
-

-

--

.

I

11

---

29+

27+

-----

I

I

I

29+

cingulum, with poorly defined peripheral
cusps in the inner side. The root has
faint groove in the inner side, whereas
the outer groove is developed in thelower half only ; the root is curvedPliocene Pinniped Remains from Kanazawa, Ishikawa Prefecture, Japan

inward and slightly forward.
No. 2 (Figures B, 2a, 2b, 2c.). Cross·section in neck is sub-elliptical, withar longer antero-posterior diameter.
The crown is moderately high, conical,
and bluntly pointed at the tip, withsharp cutting edges and with one welldefined (posterior ?) accesory cusp. The
cingulum is more or less distinct, especially in the inner side, where an irregular cusp occurs. The root is nearlystraight, with faint median depressions~.: .i:, ,.

~71:~·. ~ '.
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.

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2c

61

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.a

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10
I

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4c

Figures B, 1-4. Detached molariform teeth No. 1-No. 4.
la. Inner view of No. 1; lb. Outer view of No. 1;
lc. Upper view of No. 1; 2a. Inner view of No. 2;
2b. Outer view of No. 2; 2c. Upper view of No. 2;
3a. Inner view of No. 3 ; 3b. Outer view of No. 3 ;3c. Upper view of No. 3 ; 4a. Inner view of No. 4 ;4b. Outer view of No. 4; 4c. Upper view of No. 4.

-~:

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Figures C

62

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20rn.rn:Pliocene Pinniped Remains from Kanazawa, Ishikawa Prefecture. Japan

both on the outer and the inner sides.
No. 3. (Figures B, 3a, 3b, 3c.) is subelliptical in neck section, its longer
diameter being antero-posterior. The
crown is conical, with sharp cuttingedges and one (posterior?) well definedaccessory cusp. Cingulum is poorly
developed, and without any distinct
peripheral cusp. The root is more orless strongly grooved in the inner side,bifurcated at the apex of root, slightly
curved inward and forward.
No. 4 <Figures B, 4a, 4b, 4c.) The
crown is bluntly conical, moderately
high, with sharp cutting edges and ·with
one (posterior?) accessory cusp. Cingulum is well defined especially in the
inner side, where there is a poorly defined peripheral cusp. The root is strongly
grooved and distinctly bifurcated at a
halfway toward the point, curving strongly inward and forward.
REMARKSThe species under consideration evidently belongs to Otariidae, and is
especially closely related to the genus
Ewmetopias. As far as the fossil species
are concerned, the more closely related
to the present species are as follows :Allodesmus kenzensis KELLOGG fromthe Lower Miocene Temblor beds of theKern River region, Kern County, California. (KELLoGG, R. 1922); Ettmetopias
watasei MATsuMoTo from the "Sanuki
Formation of the Narita Series" (Upper
Pliocene?) at Umegase, Chiba Prefecture,
Japan. (MATsUMOTO, H. 1925, 1926);
Ezmzetopjas sinanoensis NAGAO from the63

Miocene (?) Bessyo beds in Gozyo-mura,
Higashi-Chikuma-gun, Nagano Prefecture, Japan. (NAGAO, T. 1941).
The American species Allodesmus
kernensis is represented by an incomplete mandible ramus which lacks theposterior portion. Apparently it showsa close affinity in almost all features tothe present species, as far as the preserved portion is concerne:L On closer
examination, however, the present species
is different from Allodesmus in the dentition, that is, the present species has fivelower molariform teeth, without any
trace of the sixth; Allodesmus has six
molariform teeth, among which the lastone (the second lower molar M!f) is"very small, tending to disappear".
Moreover, in point of the location andnumber of the mental foramina they arealso distinctly different from each other:
Allodesmus has as many as ten mental
foramina, whereas the present species
has six, among which the one below thesecond premolar is very large in size.
The specimen of Eu.metopias watasei
is represented by the right side of theupper snout anterior to the fourth pre·molar. Because of the ill preservationof the specimen, comparison with thepresent species is hardly possible. In
this species, the roots of the premolar
and the canine are more regularly
circular in cross-section, and the snout
anterior to the canine seems to be longer
than that of the present species.
EmnetoPias sinmwensis is represented
by the anterior portion of the skull
which is " so much deformed that reconstruction is almost impossible". This

Explanation of Figures C, 1-4.
Fig. 1. Upper view of the right mandible.
Fig. 2. The second molariform tooth. 2a. inner view: 2b. outer view ; 2c. upper view.
Fig. 3. Outer view of the right mandible.
Fig. 4. Inner view of the right mandible.

r
Yoshio KA.SENO€4

species also seems to be closely related
to the present species as a whole, butdiffers from the latter in the following
features: the canine is rather small compared with that of the present species;
the premolars are more circular than in
the present species; and the molariform
teeth have ·• no trace of an anterior orposterior cusp and with a very poorly
defmed cingulum as far as observed ",whereas the present species has themolariform teeth with a distinct cusp
and a considerably well defined cingulum.
The differences enumerated above, arelikely to be considered sufficient as thereason for separating the present form
from any other fossil species hitherto
described. The writer, however, without
more materials and reference works, can
not dare to establish a new genus or
species on the present fossil. Thus thewriter tentatively designates the present
form " Al/odesmus " sp.
AcKNowLEDGEMENT
The writer wishes to express his sincere
thanks to Dr. F. TAKA! of the Geological
Institute, University of Tokyo, for his
favor extended to him in carriying out

this work. The writer's special thanks
are due to Prof. Dr. I. HAYASAKA of theGeological Institute, Kanazawa University
for his criticism and the reading of themanuscript. Finally, the writer wishes
to express his hearty thanks to Mr. T.
TAKAGI and Mr. T. HASHIMoTo for theirassistance in preparing the sketches.
References
KELLOGG, R. (1922): Pinnipeds from Miocene
and Pleistocene Deposits of California.
Univ. Calif. Publ., Bull. Dept. Geol. Sci.,
Vol. 13.
MATSUMOTO: H. (1925): ''A New Species ofFossil Eumetopias from Umegase, Provinceof Kazusa ". (in JapJnese.) Jour. Geol.
Soc. Tokyo, vol. 32. tro. 377, pp. 45·-49,
pl. m.

MATSUMOTO, H. (1926): On Two Species ofFossil Pinnipedia from Kazus:1 and SaghaJin. Sci. Rep. Tolzoku Imp. Ut1iv., ser. 2(Geology), vol. 10, pp. 13-14, pl. VI. Figs.
1, 2, 3.

NAGAO, T. (1941) : An Occurrence of a Fossil
Sea Lion in the Miocene Deposits ofSinano. Japan. Jour. Fac. Sci. Hokkaido
Imp. Univ., ser. 4, val. 6, tlo. 2, pp, 7584, 2 pis.
NAORA, N. (1944): Nihon·Honyfi.Dobutsu-shi.
(in Japanese.) July. 1944, Yotokusya,
Tanbaichi, Nara·ken, Japan. pp. 96-97, 99.

rAnnouncement

I

Bibliography of Japanese Palaeontology and Related Sciences
1941-1950
including papers published by Japanese authors as well as thoseby others which concern .T a pan and its surroundingsCompiled by

Ryuji Endo, D. Sc.
Professor of Geology and Palaeontology
Saitama University, Urawa, Japan

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Foreign subscribers free; foreign non-subscribers US $ ~.00
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Orders to be addressed to

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