fl-lt"~i.~~~~~·i~fTransactions and Proceedingsof thePalaeontological Society of Japan
New Series

No. ·12

Palaeontological Society of japan

Junc 10, 1961

CONTENTS

TRANSACTIONS
Page

401.

Problematical markings on the under-surface of a Miocene tuffaceous siltstone, Yamagata Prefecture. japan .... Kotora ILHAI and Tamio KoTAI<A

402.

Note on lleterotrigonia subovalis (J •~•so) .................... Mitsuo NAKANO 55

403.

A fossil Rliinoccros from Kuzuu, Tochigi Prefecture, Japan ............... .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Joji NAcAsAwA

40-1.

51

63

A new species of .-lp/ie!astcr from the Lower Cretaceous of japan ....... .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keisaku TANAKA and Matsutaro SIIIBATA
405. On some consideration of the molluscan fauna from the Asagai formation.......................................................... Saburo KAN:-<o406. A find of !110110/is (En!omouolis) from eastern Yamaguchi Prefecture, Japan............................................................ Akira 1-IAsr:
PROCEEDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

68
73
79
88

President: Teiichi KosA v AsH I
Councillors: Kiyoshi AsANo (Editor of ''Fossils"), Riuji Er·mo (Planning), Haruyoshi
FuJI~IoTo, ShoshirollANZAWA. Wataru HAsHIMoTo (Treasurer), Kotora HATAI,

Ichiro HAYASAK,,,

Koichiro lcJHKAWA,

Nobuo lKEBE, Teiichi KoBAYASHI,

Tatsuro MATsuMoTo, 1\iasao MINATo. Tokio SIHKAliiA (General Affairs), Fuyuji
T.\KAI (Editor), Ryuzo ToRJYAI-.JA
Secretary:

Tctsuro l-IANAI

Assistant Secretary:

Takeo IcHIKAWA

All Communications relating to this Journal should be addre.o:;sed to the
PALAEONTOLOGICAL SOCIETY OF JAPAN
Geological Institute, Faculty of Science, University of Tokyo, japan

Trans. Proc. Palaeont. Soc. japan. N. S.. ~o. 42. pp. 51-54. June 10. 1961

-101.

PROBLEl\IA'l'ICAL MARKINGS ON TfiE UNDER-SURFACE
OF A MIOCENE TUFFACEOUS SILTSTONE.
YAl\IAGATA PREFF:CTURE. JAPAN*
KOTORA HATAI and TAMIO KOTAKA
Institute of Geology and Paleontology. Tohoku University
Jll/I'~Y~tpflj~c~,c7)-lj;jJt :'i'~i IJ.I:c7)J1!!MffiHii.::. ~iLH ~ .h k.

markings >:,:;r~;f&: l. !li~t

fl:. ..,d~A-J: .::::..O:J c7)('j'Q markings clt~l- ~~"#O)JWffl~~~~~L.t..:,~1t tj. tJE • ·J' ilfJ R; ;)~with interesting markings found in the
tidal zone of Nobiru beach, :Vlono-gun.
\liyagi Prefecture. because they are
similar to one another.
Here the writers thank Dr. Yushi Fu:-; ..v
YA~IA of the Department of Geology.
Faculty of Education of the Tohoku
University for his guidance in the field
and help in collecting the problematicalmarkings. Particular thanks are due toProfessor lsao MoTOJ\IURA of the Institute of Biology of the Tohoku UniYer·
sity for his kind information and sug·gestions on the markings in the tidal
zone of Nobiru beach above mentioned.
Thanks are also due to Messrs. Minoru
SAITO of the Kagawa University andHiroshi NooA of the Tohoku University
for their cooperation in observations
along the beach at Nobiru.

Introduction and Acknowledgements

Il is well known to all who havestudied the under-surface of sedimentaryrocks that various kinds of problematicalmarkings are generally well preserved
there.
These problematical markings
range from minute to rather large sizes
and show a wide ,·ariety of shapes, but
usually are more or less horizontal inorientation parallel with the bedding
plane of the strata in which they arepreserved. Such markings have received
various names as hieroglyphs, fucoids
and others and have been ascribed to awide variety of organisms and less commonly to physical origin.
Very fortunately the senior writer incooperation with Dr. Yushi Fu:-.:AYA:>.tA
of the Tohoku University succeeded in
obtaining some peculiar problematicalmarkings from the under-surface of asiltstone exposed along the Sagae River
below .l\lizusawa. 1\lazawa-machi, NishiMurayama-gun. in the western part of
the Yamagata Basin. Yamagata Prefecture. This problematical marking is
described in this article and compared

Description of the Fossil Sample

The fossil sample was found on theunder-surface of a marine tuffaceous
siltstone of fvliocene age exposed on theright bank of the Sagae River below
tvlizusawa in the western part of Mazawamachi. Nishi-!\lurayama-gun, Yamagata
Prefecture. The markings are well preserved except for their slight deforma-* Heccived Oct. 1. 1960: read at 76th meeting of the society at Matsuc. Sept. 2-t 1960.
fil

52

Kotora HclT.!ll and Tamio KoTAKA.

tion by subsequent pressure of theoverlying sediments and occur in alamina of fine tuff at the base of the
tuffaceous siltstone above mentioned and
immediately above the underlying tuffa·
ceous sediments.
The markings (Fig. 2) show a rather
wide range in detail shapes of the moreor less cyclindrical tubular or rod-likestructures seen from below. These rod·
like forms measure about from 0.5 to
1.5 millimeters in width and up to about
10 millimeters in maximum length. Someare apparently circular and others are
more or less compressed circular incross-sections; they were moulded in acast of rounded section. They may befrom almost straight to variously curved
to the right or to the left. :\II are de·void of striations either of concentric or
longitudinal or diagonal directions withregard to the longer axis of the rods.
and the surface or more correctly theirlower parts. appear to be quite smooth.
However. at places these rod-like struc·t_ures are at times broken as if by~racking at the time of consolidation orby subsequent pressure of the loading
sediments. The rods show at placesbulding, pinch-and-swell shapes. a gradu·
al widening or narrowing along theirlengths. and overlapping of one upon
the other. Superficial branching struc·tures are also apparent. f.lany of theshort rod-like structures cross one an·other at various angles. overlap several
times at the same position to form athickened aspect. and where bulding or
pinch-and-swell portions occur it isnoticed that this is due to thickeningby overlapping or crossing of one on
the other.
Because the under-surface of thistuffaceous siltstone is not a straight or
horizontal one, but provided with undu·
latory aspect. it is inferred that either

deposition was rapid and unequal load·
ing occurred and that this resulted in
the deformation of the original struc·tures. Also because the strata preserv·
ing the peculiar markings have been
subjected to subsequent crustal distur·bances, it may also be thought that theeffect is reflected in the varied shapesof the rod-like structures particularly intheir more or less deformed shapes.
Should the subsequent agencies ,,·hichwould have strong influence on the re·shaping of the rod-like structures bebrought into consideration and the pre·served peculiar markings restored. it isinferred that their original shapes \\·ould
have been straight to variously curved
rod-like structures attaining no great
length or width, and that the circularcross-sections may not have been theoriginal. This inference results fromthat shallow but long and narrow ex·
cavatio.ns in muddy or soft sediments if
fine grained may be subjected to fillingto the original level of the sediments
before they were excavated. Continued
deposition of fine grained sediments
causes filling of the excavations andfurther sedimentation results in theircomplete coverage and preservation. Bysuch procedure the peculiar markings
on the under-surface are negatives ofthe original markings made on the sur·face of the underlying sediments.
Marldngs in the Intertic!al Zcne
of Nobiru Beach
Having had the opportunity to Yisit
Nobiru beach. :'vlono-gun, l\tliyagi Prefecture at the time of low tide. Yarious
interesting markings were observed andphotographed. among which one is des·cribecl in the following lines.
The markings , Fig. 1) were found im·pressed or excavated in fine grained sands4 01.

lHarkings on Under-surface

near the strand line·at lowest tide forming a kind of z01ie parallel with thebeach and extending at least 500 metersin length and about two to five meters
in width· were measured. Thev werepartic-ularly well observed near theterminal portions of small rills flowing
from the near the strand line seawards
during low tide. At the time of observations these markings seem to haveodcupied areas slightly higher than theseaward adjacent area and lower thanthe landward adjoining area, although
the difference in height was slight.
The markings consist of a variety ofshapes. being from straight to curved
in right or left directions. and all were
noticed to represent shallow and narrowtroughs or excavations with parallel·
sided walls. In width they measured
about 0.5 to nearly three millimeters
and in length up to about 10 centimeters
in maximum. The excavations or trails
as they may be called were noticed tocross-one another. appear as branchingat places, haYe abrupt terminal parts or
obscure ones, be partially filled with the
sandy sediments, retain their original
shapes and be developed in an enormous
number as is forming clusters. Thus
it is evident as also shown in the photograph (Fig. 1) that their shapes andsizes are quite varied.
Near the afore-mentioned rill-marks
the development of the peculiar mark·ings described above decrease in number
and structure and there are found manysmall holes in the sand. Also some holes
were recognized in areas \\·here the trails
were dense in arrangement. All of thetrails seemed to be parallel or horizontal
in position \\'ith the sandy deposits inwhich they are impressed and none suggested a different orientation. The holes
were all found to have vertical positionsin the sand beach.
.~.

~

[,3

These markings just described in the
abo\·e are due to Gan;marus. small
crustaceans measuring about eight to
ZO millimeters in length and whose spe·
cies live in brackish and marine waters
extending from the region of Northeast
japan southwards to Kyushu in geo·
graphical distribution, and generally
live in shallow waters. One of its species Gammams ( Ricu!ogammarus) /acustris(G. 0. SARS) is knO\vn to live in fresh·water lakes of ~vlanchuria and l'vlongolia.
The one just stated to live in brackish
and marine waters is Gammams I Rimt!o·gammams) nippoJU!1lsis UE~w. and themarkings above described are due tothis species. Here it should be statedthat Professor Isao IvloToMUAR of the
Tohoku University provided the senior\Vriter with information concerning themarkings described above. The small
crustacean can be caught in large num·bers and is used for bait by the local
fishermen.
Interpretation of the Fossil :\Iarkings

The fossil markings described in thisarticle show rounded under-surface andsince this is the negative, it may beinferred that they originally weremoulded in long and narrow casts withrounded bottoms showing trail-like appearance. Although their shapes as
now preserved can be considered to havebeen slightly deformed by subsequent
compression by the pressure of the over·lying sediments and probably also by
crustal disturbance. their original forms
are thought to have been analogous withthe markings made by Gammarus.
If the fossil markings can be inter·
preted as made by some marine animal
similar to or by Gmnmams itself, thenit may be possible to analyse the environment under which the sediments

54

Kotora H'iT.-!1 and Tamio Ko1~4IO

prescn·ing those structures were deposited. The environment would thus beinterpreted to haYc been in the tidal
zone or nearby. and since the beds preserving the structures are now truncated,
evidence suggesting the ancient shoreline could not be found. IIowe\'er. it
may be postulated that the tuffaceous
siltstone was originally deposited on abroad and shallow area near to theshore, if the fossil markings can be
accepted as analogous with those madeby the Recent Gammams.
Since other kinds of markings are alsopreserYed on the under-surface of thesedimentary rocks(i\lioccne' of the terrain
along the Sagae River in '{amagata
Prefecture. the writers hope to study
other structures before presenting any
conclusion as to the paleo-environment of
the rocks preserving the structures.
References
E:-.rERY. K. 0. (19-!4) : Beach 1\Iarkings madeby Sand Hoppers. Jour. Sed. Pelr .. z·o/.
14. 110. 1' pp. 26-28. pl. l.
FE:->TO'>. C. L. and M.A. FE:->TON (1934) :Anthraria-like Markings made by Annelids and Snails. Pan·Amer. Geol.. t•ol.
LXI. May and June. pp. ~6,1 :!92. pl. 28.
Illustrated Encyclopedia of the Fauna ofJapan (19-19) : Hokuryu-kan Book Co ..
Tokyo, refer to pp. 827-282. fig. 2377.
Yo:>:GE, C. M. (1949): The Sea Shore. Collins
St. James's Place. London. refer to pp.
153. 253-264.

Text-figures.

Markings on under-surface.

Fig. 1: Markings of Gammarus (Rit'ZIIogammanes) nipponensis UE!'\0 in the intertidal zone at Nobiru bead1, Mono-gun. Miyagi
Prefecture.
Fig. 2: Fossil markings on under-surfaceof Miocene tuffaceous siltstone on right bankof Sagae River below 1\Iizusawa. Mazawamachi, Nishi-Murayama-gun, Yamagata Prefecture. IGPS coiL cat. no. 78264.

Trans. Proc. l'alaeont. Soc. Japan, X. S., No. 42, pp. 55-62, pl. 9, June 10. 1961

40~.

0l'OTE ON HETEROTRIGONIA SUBOVAL!S (JIMBO)*
l'vi!TSUO NAKANOInstitute of Geology and Mineralogy, Faculty of Scien~:e,Hiroshima University

Heterotrigouia subm•alis (Jt:-.wo) 1.:.-::>~ --c O)~cili'i::~l::imif1:=3.2:rn~~f*5Jij~O)~IJ(O)~<·*:.::.-::>~ -c. 15'1=.¥D~Ii~Wf'1E~TTL ·· .:,11)1J!il~·!it.N:;.:.f:!:~ ·· -i"O)~llfi'Jr.<~O)'l!:(til~?¥1.1 t.:.
Trigouia smcatai YF.HARA t Apiolrigonia jimboi NAKAl\:0 ii.:C.h.:f.h. H. subo~~alis 0)

MG~~~--~~~~=~v:~~L~.

~

~

*•

mature and adult forms of I-I. subora/is.
respectively.
The materials dealt with in this paper
were collected by late Kotora J nmo,
Tatsuro MATsntoTo, and the writerfrom the lkushumbetsu district inl\likasa·city of Central Hokkaido andstored in the Geological Institutes of
the University of Tokyo (GT). Kyushu
University (GK), and Hiroshima Univer·sity tGHl.
The writer wishes to express his
sincere thanks to Prof. Sotoji htAJ\tUR.-\of the Hiroshima University, Prof. Tei·
ichi 1\ouAL\Stll of the Cniversity ofT~kvo. and Prof. Tatsuro MATst:~toToof t.he Kyushu L:niversity at Fukuoka
for their kind guidance and continuing
encouragement.
The writer records
here his cordial thanks to :'vlessrs.
Tomowo OsE and lchiro HAYASIIt of theSumitomo Colliery Company for thefacilities to survey the lkushumbetsu
district and to \lr. Yoshiro UEDA of theGeological Survey of Japan and 1\'lr.
Ikuwo OnATA of the Kyushu Gniversity
for their assistances.

Introduction and Acknowledgements

fleterotrigonia Cox is considered probably to be a genus of the subfamily
Trigoniinae KoBA YASHt, and is wellcharacterized by its outline and surface
sculpture. This genus is characteristic
in the Northern Pacific from the upper
Albian I?) to the Santonian. Tri~-:rmia
subol'alis is a typical !Ieterotrigonia. andhad been originally described by J•~•so(189-1) from the " Trigonia Sandstone "(Cenomanian-Turonian) of Pombetsu in
Jkushumbetsu, l\likasa-city, Central Hokkaido. Its occurrences were reported bysome authors from the Cenomanian to
the Santonian formations in the Yezo
geosynclinal region including Hokkaido.
Sachalin. and Kamtschatka. Recently,
the writer had a good chance to visit
to the Ikushumbetsu district and collect·
ed numerous specimens of Heterotri){oniasubrJt'alis from various places. As aresult of this palaeontological study, it
is recognized that fl. subovalis presents
remarkable change of characters in onto·
genetic development and Trigonia smralai
and Apiotrigonia jimboi must be an im·

Subfamily Trigoniinae KoBAYASHI, 195-1-- - - - - -- ; Rc~eived Oct. 14. 1960; read at the annual
meeting of the society at Tokyo, Jan. 15, 1961.

Gen us Heterotrigrmia Cox, 1952

55

5G

Mit suo NAKANOT)pe species :-Trigo11ia dil'ersicostata \VutTE·
AHS, 1876. Haida formation (Up. Albian?) of Queen Charlotte series: British
Columbia.

Diagnosis:-Shell small to medium insize. pyriform to triangularly ovate, in·equilateral, moderately inflated. Umbo
narrow, rather prominent; beak opisthogyrous and antero-rnesial. rvlarginal andescutcheon carinae visible only nearumbo where the surface is tripartite
distinctly and ornamented with several
plain concentric costae and costellae.
Escutcheon fairly broad, depressed, provided with transverse, plain or tuber·culate costellae.
Area narrow, withseveral, radial. plain or tuberculatecostae which are sometimes bifurcatedor e\·anescent later. Flank with twoseries of plain or tuberculate costae.
except in the vicinity of umbo: anterior
series of costae first su bconccntric, but
become oblique, sometimes undulated or
obsolete. in the later stages : posterior
series consists of radial or subverticalcostae which are often bifurcated: someradial or vertical costae confluent withanterior subconcentric ones.
Growth-lines or concentric bands sometimes well developed on the wholesurface.
List of Species:Heterotrigonia grmwsa i\ AK A~o. I!!51 . .Midd lc
formation (Santonian) of Himcnouragroup; Amakusa. Kyushu, Japan.
T1·igonia subovalis ]t:vtBO, 1894. CenomanianSantonian: Central Hokkaido of Japan,
South Sachalin and Kamtschatka.

Remarks :-This genus is closely similar to Apiotrigmzia and lotrigonia in outline and surface costation, but is easily
distinguished by the presence of a small
number of radial costae on the narrowarea.
In the early stage of growth. thewhole surface is sculptured with se,·eral,plain concentric costae and costellae andtripartite distinctly by a marginal and an
escutcheon carina. It is sometimes recognized that in the umbonal region the concentric costae rapidly become L-shaped
costae through V-shaped costae and radial
costae on the area appeared suddenly.
In the later stages, the characteristic
L-shaped costae on the flank and theradial costae on the area are sometimes
evanescent.
As already pointed out by the writer(1957), the shell outline is rather constant in this genus, but the ornament·
ation is somewhat variable. Costae in
granosa are tuberculate, but plain indit•ersicuslata and subovalis. Dit•ersicostata
has transverse and horizontal costae on
the anterior part of the Hank, and its
area is provided with a few distinct
radial costae in all stages. In suhot'ft!is,transverse and horizontal costae become
gradualJy oblique. more or less undulate,and disappear in the later stages, but
the concentric bands are well developedon the whole surface. Its area is sculptured with several radial costae, butthey are not well recognized in the laterstages. In the shell out line, grmwsa
is trigonal-ovate and small-sized, butpyriform in subovalis and diversicostata.
Diversicostata is medium-sized, while insubovalis the adult shell measures 45-60
mm. long and 35-43 mm. high. Escutcheon is well developed in subova/is andgranosa, but absent in dioersicostata.
Trigrmia sawatai YEHARA represented
by a single specimen from the •· Trigonia
Sandstone •· of Ikushumbetsu in l\1ikasacity Central !Iokkaido, is most probably
an immature form of Trigonia subovalis]1~mo as can be judged from the shellform and the surface costation. In theearly stage, !lpiotrigonia jimboi NAKANO
has radial costae on the area and is402.

Note on Heterotrigonia subovalis (]IMBO)

similar to subo~~a!is and sawatai. Accord·
ingly. jimboi indicates probably an adultstage of subovalis.
It is observed that two topotype speci·
mens of Trigonia newcombei PAcKARD,
from the Haida formation of the Queen
Charlotte series in British Columbia.
now stored in the Kyoto University arequite different from each other. The
larger one (J. ~1. 10179) having radial
costae on its broad area, may be amember of I!eterotrigouia, but the otherone U. l\1. 10180) is probably a memberof Apiotrigonia because of its narrowsmooth area.
Distribution :-Upper AI bian (?) to
Santonian in the Northern Pacific.
Heterotrigonia subomlis (JI~Iao)
Plate 9. Figures 1-U
18!H. Trigonia

subol'alis.Tt~!BO.

Pal.

.4bh ..

/1. F. Bd. 2. Ht. 3. pp. 188-189. pl. 8,
fig:>. 5. 5a.

1923. Trigo11ia smmtai YEHARA. japan. jour.
Geo/. Geogr .. Vol. 2. No. 3, p. 80. pl. 10.
fig. 9.

1957. Apiotrigouia jimboi .NAKAi\:0. Ibid .. Vol.
28. Nos. 1-3. pp. 115-116. pl. 8, figs.

5-7.
1957. Heterotrigouia subot•alis ~AKAI:'O. Ibid.,
Vol. 28, Sos. 1-3. pp. 118-119. pl. 8,
figs. 13-15.
1960. Megatrigonia (/Jpiotrigouia) subowlis
LtWEROSKAJA. Palaeout. Bull .. 2. Lenin·
grad, pp. 251-252. pl. 5. figs. l-3.

1\Jaterial :-Older Collections in the
University of Tokyo. Holotype. GT. Cr.
1285. from the " Trigouia Sandstone" atPombetsu in Ikushumbetsu, Mikasa-city,
Central. Hokkaido (Coli. K. ]1~mo); besides this in ]t~mo's collection there are
the following five specimens: GT. Cr.
908a and 908b from the same formation
at Pombetsu in lkushumbetsu and GT.
Cr. 1284a, 1284b. and 1295 from the same57

formation at Katsurazawa in lkushumbetsu.
In !vi. NAKAr-;o's collection. there areabout 70 fairly complete and incomplete
specimens from the same formation inlkushumbetsu of tvlikasa-city. GH. NM.
H. 101-llS and GH. NM. H. 120-124 werecollected from the Calycoceras zone of
the .. Trigonia Sandstone " at Keirimbashi
in Shimokatsurazawa of Ikushumbetsu
and GH. Nrvl. H. 119 was obtained fromthe Inoceramus lzobetsensis zone of theupper member of the same formation
at an old site of a quarry near the
Katsurazawa dam-site in Kamikatsurazawa of lkushumbetsu.
In T. l\IL\TSDioTo's collection, GK. H.
6035-37 from the Ca!ycoceras zone (?J of
the same formation at T. 1\L"-Tsu:-..toTo's
Joe. IK-2021 along the Pombetsu riverin Ikushumbetsu. Besides this MATSC·~toTo's collection contains a number of
unregistered specimens from the sameformation in the same district.
Description :-Shell medium to fairly
large in size. triangularly ovate topyriform, moderately inflated, inequi·lateral. broader than high : antero-dorsal
margin short and nearly straight orslightly convex: antero-venlral rounded:
ventral broad and gently arcuated:siphonal rather broad and well rounded:
postero-dorsal long and concave. Umbosmall. rather prominent, sculptured with
about 5 plain concentric costae: beakopisthogyrous, pointed at about a fourth
to two-fifths from the front.
Flankwith two series of plain costae except for
the umbonal region: anterior costae subconcentric but soon become oblique, moreor less undulated, and disappear later:
posterior radial or subvertical costae
broadened, sometimes bifurcated and dieout ventrally: about a third of posterior
radial costae reach ventral periphery.
Shallow ante-carina! depression some-Mitsuo N.-!KA1YO

58

times well developed. l'vlarginal andescutcheon carinae distinct only nearumbo. Several radial costae on thearea except for the umbonal region.
first distinct but soon obsolete in the laterstages.
Median furrow shallow andindistinct. Escutcheon broad. depressed,
provided with numerous plain transverse costellae which are first subcon-

centric and later oblique.
Growth-lines distinct in all stages, especially crowded in the area; in the adultstage concentric bands well developed on
the whole surface. Internally, a radial
ridge presents on the area, coincides approximately with the middle of thearea: ventral periphery slightly plicatedor sometimes smooth. Test rather thin.

Measurements in mm.
Specimen

Valve

LengthHeight

L/H---- -- -----GT. Cr. 1285
2. GT. Cr. 128-ta
3. GT. Cr. 128-tb
4. GT. Cr. 1~95

*1.

5.

Gil. NJ\1. H. 101

6.
7.

Gil. NM. H. 10~
GH. NM. II. 103

8.

Gil. NM. H. 104

9.

GH. N:vl. H. 105

10.

GH. ?'\J\1. H. 106

11.

GH. NM. II. lUi

12.

GH. Nl\L H. 108

13.

GH. NM. H. 109

U.

GH. NM. H. llO

15. GH. NJ\1. H. 111
16.

GIL l'il'vl. H. ll2

17.

Gil. NM. H. 113

18.

Gil. NM. H. lH

19.

Gil. NM. H. 115

GH. NM. H. 116
21. GIL NM. H. 117
22. Gil. NM. H. 118
23. GIL ~M. H. 119
24. GH. NM. H. 120
25. GK. H. 6035
26. GK. H. 6036
27. GK. H. 6037
20.

BivaiYed
Left
Left
Right
Left
Right
Left
Left
Left
Left
Left
Right
Right
Left
Right
Left
Left
Left
Right
Left
Left
Left
Right
Right
Left
Left
Left

35.0
53. 0

30.0

1. 17

37.0

1. 43

44.3

38. 0

43.0
47.5

1. 27
1. 23

14.8

35. 0
35.5
13.5

56. 0

39. 1

I. 43

11. ll8. 0

33. 0
44. (I2•1. 0
29.2
37.5
25. 0

1. 38
1. 38
1. 50
1. 39
I. 38
l. 26
I. 40
1. 33
1. 30

52.0
3-1.5

1. 34

1.10

23.3

18.5

44.2

31. 5

50.0

37.5

·12. 5
44.6

31.7
35.6

56. 0

-10. 5

1. 38

63. 0

42.5

l.H
1. 45

l. 25

17.8

13.0

22.0
32.0

16. 0

1. 37

25.0

I. 28

19.2

16.2

1. 20

27.0

18.5

11. 0

8.2

9.8
36.7

24. 1

1. -15
1. 34
1. 31
l. 52

7.5

* Numbers correspond to those in text-fig. 1.
Remarl~s :-In a recent
paper, thewriter (HJ57) noted that the area issmooth in Apiotrigonia jimboi. but radi-

ally costellate in 1'rigonia subova/is andT. sawatai the latter of which resembles
T. subovalis in ornamentation and shell

402.

Note on Heterotrigonia subovalis (}IJIBO)

H

50
mm.
18

40

3

4 •

11
15 •••
2

• s·
30

1•

22. 1 ~ •
20

.•

13
23
6
8

10

9

•

"19

•• 7

16 •• 17
10.
•14

27

24

. •

21

20

•
26 ••25

0

10

20

30

L

40

50

fiO

70

mm.
Text-fig. I.

Proportion of height to length of Heterotrigonia suboralis (JI~IBO)

form. The radial costation on the area
are, however. well observed on somespecimens lpl. 9. figs. -ta-b, fig. 13) of
Ap. jimboi before hand. Because of theill-preser\'ation and the effacement of
the costation through growth. in manycases the radial costation on the area
and the characteristic L-shaped costationon the flank arc not well observed.
Like many other trigoniids this spe·
cies presents remarkable change ofcharacters in ontogenetic development.
The shell form is. however. rather constant through growth. The outline istrigonally ovate to pyriform, and thebeak located at a fourth to two-fifths
from the anterior end.
The height·
length proportion ranges 1 : 1.10 to1 : 1.50. mostly 1: 1.30 to 1 : 1.40.
Shell (about 1.5 mm. near beak) in thefirst stage of growth is recognized occasionally in some specimens IGH. Nl\1.
H. 104 and GK. H. 6035:. In this stage,
the whole surface is provided with about
5 plain concentric costae and costellae anddistinct three carinae. Shell is similar
to that of Frenguel/ie!la because of theabsence of the radial costation on its
area.
In the next stage shell ~about 3 mm.
near beak) is tripartite distinctly andradial costae appear suddenly on its
area. Succeeding about 3 concentriccostae on the flank change gradually
into L-shaped costae through V-costae.
In the succeeding stage, when theshell is about 10-25 mm. long and 8-20
mm. high. the flank is sculptured with
8 to 17 subconccntric costae and 4 to 10
radial or subvertical costae. Costae on(i(lMitsuo NAKANO

the area number .! to 6. In the formin figs. 2a-b on pl. 9 (GH. NM. H. 1191.
costellae on the escutcheon number
about 17 and they are connected with
1he coarse growth-lines on the area.
In the following stage. the shell isabout 35 mm. long and some 30 mm. highand the costation near the umbo isusually uncertain. The main part of
the flank is sculptured with 8 to 14
radial or subvertical costae and about
15 subconcentric costae. Radial or sub·vertical costae in this stage are some·times bifurcated near the ventral peri·
phery, and subconcentric costae on theanterior part of the flank are slightly
oblique. more or less undulated, andsometimes obsolete in the antero·ventral
margin.
Radial costae on the area
number 6 to 10. and often evanescentposteriorly. Costellae on the escutcheon
number about 18 in some forms. Con·
centric bands are developed in thevicinity of the marginal part andgrowth-lines are crowded especially on
the posterior part.
In the last stage. the shell is 45-60 mm.
long and 35-.!3 mm. high and the surface
costation in the earlier stages is commonly
not well observed. There are, however.
10-15 radial costae and about 15 sub·concentric to transverse costae on theflank. Subconcentric or transverse costae
on the anterior part are usually undul·
ated and oblique. Costation on the area
is evanescent, and the escutcheon orna·
mented with numerous transverse coste!·lae. Strong concentric bands are wellde\·eioped on the whole surface.
As discussed above. the surface sculp·
ture is quite variable through growth.
Y EBARA's sawalai resembles the earlystage of the illustrated specimen (pl. 9,
fig. 7) which is a typical form of J IMBo's
subovalis. On the other hand, the earlystage of Apiolrigonia jimboi is quite

similar to subovalis as can be judged
from the surface costation. Therefore,
SaiCatai and jimboi must indicate as animmature and an adult form of subm•alis,
respectively.
Variation:- This species has a certain
degree of the variation on its surface
ornamentation. For example, the sculp·
ture is not always equally even in
specimens of similar size. Because of
ill-preservation, the exact extent of thevariation is uncertain. There are. how·ever, a Rutitrigonia·like form (pl. 9, fig.
1) on which the typical L·shaped cost·ation is obsolete and the concentricbands are well developed. On the other
hand, a specimen on fig. 6 in pl. 9 has
a typical L·shaped costation which isusually evanscent in the anterior part.
In the early stage, concentric striae on
the area are strong and crowded in theillustrated form (pl. 9, fig. 2). but they
are weak in the other specimens (pl. 9,
figs. 5 and 10). In the adult stage, theradial costation on the area is commonly
not well observed, but well developed in
the specimen on fig. 13 in pl. 9. In
some unfigured specimens, the visible
radial or subvertical costae on the pos·terior part of the flank all reach theventral margin.
Comparismz :-This species is charac·terized by the presence of the L·shaped
costation on the flank and the radial
ornament on the area.
This species resembles closely Apio·
lriKonia minor (Y AnE and NAGAo) and its
allied forms from the Cenomanian to theMaestrichtian in japan, but is easily distin·
guished from the latters by the presenceof the radial sculpture on the narrow area.
1/etemtrigonia diversicostata (WHIT EAVEs)
from the Haida formation of the Queen
Charlotte series of British Columbia isclosely allied to the early and middle
stages of the present form, but differs by402.

Note on Heterotrigonia subovalis I}IMBOI

the absence of the transversely costellac
escutcheon. As compared with flpiu·
trigonia newcombei (PACKARD) from the
Haida formation in British Columbia,
this species is larger than the latterand its area is radially costellate. Helem·
trigonia granosa NAKANO from the middle
formation {probably Santonian) of the
Himenoura group at Wadanohana in
Ryugatake-mura, Amakusa-gun, Higo
Prov., Kumamoto Pref.. resembles thisform. but differs in having the smaller
shell and its costae are all tuberculate.
Apiotrigouia turcmenensis (ARcHA:>;GELSKY)
from the Cenomanian of Turkestan issimilar to the adult form of the present
species. but differs by the absence ofthe radial sculpture on the area.
Occurrence :-Abundant in the 1\lantel·
liceras (?) zone (lower Cenomanian) to
the Inoceramus lwbetsensis zone (middle
Turonian) in the lkushumbetsu district,Mikasa-city, Central Hokkaido. Comparable specimens were reported fromthe Upper Yezo group in South Sachalin
and the Gyliakian formation (CenomanianTuronian) of Kamtschatka.
Heferences
ARC!IA;o.:GELSIO', A. D. (1916): Les Mollusquesdu cretace superieur du Turkestan. Mem.
Com. geo/. Petrograd, N. Ser., /iL·r. 152. pp.
1-57. pis. 1-8.
Cox. L. R. (1952) : Notes on the Trigoniidae.
with Outlines of a Classification of the
Family. Proc ..\Ia/. Soc. London, val. 29.
pts. 2-3. pp. 45-70, pis. 3-4.
]!:>.lBO. K. (1894): Beitrage zur Kentniss derFauna der Kreide formation von Hokkaido.

Gl

Pa/aeont. Ablwudl., 11/. F. Bd. 2, lit. 3. pp.
1-19-19-1. pis. 17-25.
KoBAYASIH, T. (1954): Studies on the Juras·
sic Trigonians in Japan. Part I, Prelimi·
nary l\otes. Japan. four. Geol. Geogr.. l'ol.
25. //OS. 1-2. pp. 61-80.
- - and K. MORI (195-t) : Studies on theJurassic Trigonians in Japan. Part 2.
Prosogyrotrigonia and the Trigoniinae.
Ibid.. t•o/. 25. 11os. 3-.J. pp. 155-175. pis.
15-16.
LtwERowsKAJA. E. V. (1960) : Stratigraphy
and Fauna of the Upper Cretaceous Formation in the East Coast of Penshina
Bay. Palaeo111. Bull.. 2. Leuingrad, pp.
231-261. pls. 1-6.
MATSOIOTO, T. (1959): Zonation of theUpper Cretaceous in Japan. Mem. Far.
Sci. Kyuslw Uniz• .. Ser. D. z·o/. 9. 110. 2.
pp. 55-93. pis. 6-11.
NAKA:>;O. M. (1957) : On the Cretaceous
Pennatae Trigonians in Japan. Japau.
.Tour. Geo/. Geogr., t•ol. 28, 110s. 1-S. pp.
107-120. pls. 8-9.
PACKARD. E. L. (1921) : Trigoniae from the
Pacific Coast of North America. U11it'.
Oregon Pub/., 1'0/. 1. 110. 9, pp. 1-35, pis.
1-11.
WHITEAVES, ]. F. (1884): Mesozoic Fossils.
vol. I. Ceo/. Sun•. Ca11ada.
YABE, H. (1927) : Cretaceous Stratigraphy of
the Japanese Islands. Sci. Rep. Tohoku
Imp. Unit•., 2nd Ser.. 1'01. 1 1. 110. I. pp.
27-100. pls. 3-9.
- - and T. NAGAO (1925) : New or Little·
known Cretaceous Fossils from :\orthSachalin (Lamellibranchiata and Gastropoda). Ibid., 1'0/. 7, 110. 4. pp. 111-12-t. pis.
28-29.
YEHARA, S. (1923) : Cretaceous Trigoniae
from Southwestern Japan. Japau. four.
Geol. Geogr.. t·o/. 2. 110. 3. pp. 59-8-t, pis.
8-13.

62

Mitsuo NAKANO

Explanation of Plate 9
All natural size except for figs. 5 and 10.

Heterotrigouia suboNtlis (JtliiOO) . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 57
Fig. I. Lateral view of an adult right valve specimen (GH. Nl\1. H. 115). showing Rutitrigouia-like ornament on the t!ank: Ca(\'coceras zone of the lower member of the.. Trigonia Sandstone" at Keirimbashi in Shimokatsurazawa. Jkushumbctsu, i'vlikasacity. Central IIokkaido.
Figs. 2a-b. Lateral and posterior ,-iews of a modeling cast of an immature right valve(GH. :i\~1. H. 119) : Inoceramus lrobelsensis zone of the upper member of the " Trigonia
Sandstone" at an old site of a quarry ncar Katsurazawa-dam, 1\amikatsurazawa.
Ikushumbetsu. Mikasa-city. Central I-lokkaido.
Fig. 3. Lateral view of an adult left valve specimen (GI-l. NM. H. 107).
Figs. 4a-b. Lateral and posterior views of an adult left valve (GI-l. Nl\-1. H. 103).
Fig. 5. Lateral view of an immature left valve (Gil. NM. H. 10.!). x2.
Fig. 6. Lateral view of an adult left valve (GH. N:\1. H. 101). showing L-shaped costationon the Jlank.
Ca/ycoceras zone of the "Trigonia Sandstone" at Keirimbashi in Ikushumbetsu,
Mikasn-city.
Fig. 7. Lateral view of a modeling c;,st of a typical form (middle stage) of a left valve(GK. H. 6037) (Coli. T. MATSD!OTo): Ca/ycoceras zone (?) of the upper memberof the same formation at T. ~<lATStJMOTO's Joe. IK-2021 along the Pombetsu riverin Ikushumbetsu. Mikasa-city.
Fig. S. Postero-lateral view of an external cast (Gil. NM. H. 124) of a right valve inthe middle stage.
Figs. 9a-b. Lateral and posterior views of a right valve specimen (GIL NM. H. 122) inthe middle stage.
Fig. 10. Lateral view of an immature right Yalve (GH. Nl\-1. II. 102). x2.
Fig. 11. Lateral \·iew of a left valve (GI-L NM. H. 105) in the middle stage.
Figs. 12a-b. Lateral and posterior \'iews of an early adult stage of a left valve specimen(GH. N:\L H. 106).
Fig. 13. Postero-lateral view of an external cast of an imperfect right valve specimen(GH. NM. H. 121) in the adult stage, showing the obsoletion of the radial sculptureon the area.
Fig. J.J. Postero-lateral view of an external cast of an imperfect left valYe specimen (GIL)[\L H. 123) in the middle stage, showing the obsoletion of the radial costation on
the area.
Calycoceras zone of the lower member of the " Trigonia Sandstone" at Keirimbashi,
Shimokatsurazawa in Ikushumbetsu, Central llokkaido.

NAf\ANO : Heterotrigonia subovalis

Plate 9Trans. Proc. Palaeont. Soc. Japan, N. S. No. 42. pp. 63-67, June 10. 1961

-W:3.

A

A FOSSIL RHINOCEROS FROli·I KUZUC.
TOCHIGI PREFECTURE. JAPAN*

JOJI l\AGASAWA
Tokyo Gakugei Uni,·ersity~Uft:f.iJ!f-.11)-f!f!: *ft.fi:tW*IM~1:11);knth!K:fic7) ~:tot.>t.l·l? 1947 '-l'·<.:..!e.W..~.t~.

t:.. t 11) -c;B=lltrF-I#ili~IJt!H~±fiftm.ii ft!H!.!.Hfra1~PJi.U:ffl' .fi ,fil-e .:5 7.i>. l!l'!;;$:ti:t:itliJI.l::~Rllir~ fk~ J: V::kr=!Wr~.f:"t.t::t "C'- ·;;,n;, t«l'Jrtilmt~.::::lltrr=IIW t. mlrqJiiiStoR!H~'II.· •"Cii-$7HdtU.. t:..
IJ3?..11~$X~L"(1,·;;,,

1fj'Q)'Jfli~t.l,l?7,..;:.t,,tf'ffi!C1)p.qnr,li:-:.J:<w,;:, Rhinoceros mercki]..:\GER ;;::J: ( f);l"(I,•;;,C1)-c;fnj-f!l'lt.l·.:5~~ •l1.:.;f1.i::jft\.•f!ftt.~X.ohot.l:. 4-f&f.t:~~< Q)J{*'~11)j)l}bnt1Ht~ ~;h;;, 11)~-f;'j..., -cftft1l ~~}E Lt:..'- ·•c; C;l;t:.. IJ R. sp. t. L -c¥lHli·-t o,:Jkii\J~~

Material:-A fragment of right upper
jaw with P 3-l\12 in situ. the rests ofbroken P2 , iVP, and a detached right P"
belonging to the Musashino Kyodo-Kan
at Koganei, Tokyo.
Luca/itv:-A limestone fissure of Yosizawa qu~rry. Ogano at KuzuCi, Tochigi
Prefecture, japan. The specimen wascollected in December 1947.
Horizon :-Precise horizon unknown(Pleistocene).
Description :-P 2 much worn. The external wall of the crown with a distinctive parastyle almost smooth and gently
convex. Deep-seated crochet crenatedor doubled on pz_ Protocone and hypocone fused at the base. and the innerside of inner cones rounded. The anterior fossette has a narrow open inlet
at the anterior side of the crown. The
crown is bordered lingually and anteri·orly by a low basal cingulum. Lengthof the outer side of the crown is larger
than that of the inner side of the crown.
P3 : Crown moderately worn. The
inner half part of the crown preserved.
Length of the outer side of the crownis larger than that of the inner side of

The specimen dealt here was given to
the present writer for studying throughthe kindness of :'vir. Tatuo No!l.rA andthe writer had reported it as Rhinocerosreferable to R. mercki of Choukoutien in
China at the 60th annual meeting of theJapanese Geological Society, spring. 1953,
in Tokyo.
This paper is the first description
about the above mentioned specimen.
rvly cordial thanks are due to Prof.
SAKAzu!l.rE of Doshisha Cni\'ersity. to!VIr. KusAKA and Dr. OzAKI of the
National Science iVI useum (Tokyo) as
regards literature.
Description of species

Order Ungulata
Sub-order Perissodactyla
Family Rhinocerotidac
Genus Rhinoceros
Rhinoceros sp.
Text-figs. 1, 2. 3.

* Received Nov. 15. 1960; read at 78th
meeting of the society at Akita. May 13,
1961.
( ")

'"

(i4

B
oL - - - - 1r em~--)e mT c xt-fi <.< . 3

Text -fiP.:. ~T e xt-fig. 1
T e xt-fig . 1. Rhinoceros sp. Right upper pre m ol:us and mola rs, crown-vie w.
T ex t -fi g . ~ - R . sp. Rig ht upp::r second premo lar, c r own-v ie w .
T e xt-fig. 3. R . sp . R ight upp:!r fo urth pre m o la r : A, upper v iew; B, externa l view;
C, a nterior view .

the crow n. Postfossette present. Croc het
prominent, with a sma ll sp u r at its inne r
portion. Cr ista r udimentary. No a ntecrochet. The half part of the anteriorside of th e crown is bo rde red by a low
basa l cingulum. P rotocone and hypocone
fused at the base, presenting somew hat
com·ex wal l.
P1 :A comp lete crown moderately
worn. Length of the outer s ide of thecrown is larger than that of the inne r s ideof the crO\\-n. Poster ior fossette present.
Croch et prominent, w ith a spu r at its

outer portion a nd another s mal ler spurat its inne r por t ion. Cr ista more orless dist inct. No a ntecrochet. Protocone
an d hypoco ne fused at t he base. Thes ur face of the externa l wa ll of thecrown comparat ive ly smoot h a nd ge nt ly
convex, with a s ing le fold (paraconefold ) set much forwar d, ve ry close tot he parastyle. Pa racone-fold attai ns
not to t he crown base. No poster ior
fo ld on the externa l wall of the crown.
~. I ' :The inne r ha lf part of thec rown is preserved. Le ngth of t he403.

A Fossil Rhinoceros from Kuzui{, Toclzigi Prefecture

outer side of the crown is larger thanthat of the inner side of the crown.
Anterior and posterior lophes separated by a broad valley. not borderedlingually by a cingulum. But, the halfpart of the anterior side of the crownbordered by a cingulum forming an
oblique ridge. Protocone has a enamelsinus ncar the corner of the anteriorinner side of the crown.
Posteriorfossette present.
Crochet prominent.
No crista. No anlecrochet. A feeble
cusp presents at a posterior part of the
protocone.
;'\F: The inner half of the crown ispreserved. Length of the outer side of
the crown is larger than that of theinner side of the crown. Crochet pro-fi5

minent.
A feeble crista which will
disappear when more worn, presents.
There is no true antecrochet on the
protoloph, but a small fold projects into
the median valley from its outer portion, that is. external to the crochet(whereas the antecrochet always appears
internal to the crochet). We can see
the same fold or spur on li·P of the
Choukoutien R. mercki 'TElL HARD, 1936,
fig. lll and 1\-JI, 1\-F of R. mercki K.urp
from Les Grottes de Grimaldi (Bot LE
and others. 1906-1919. figs. ~. 5).
The half parr of the anterior side of
the crown is bordered by a cingulum
forming an oblique ridge. Two small
cusps present at posterior part of the
protocone.

The teeth measure as follows:
Maximumlength

po
pa

P•
1\-Jl

33mm
39mm
-!5mm
50mm

M"

51111111~J3

46 mm (at baseof «.:rown)~Iaximumbreadth
35mm
50mm
50mm
59mm
62 mm
5-1ml11 (at baseof crown)

H:ight ofcrown atouter side

Height ofcrown atinner side

47mm

25mm
20mm
25mm

~2mm

Thickness of enamel l::!y~rs: 1-2.5 111111
Length oi a root of l\1 3 • • . . 30 mm (measured directly)
Length of a root of P 3 • • . . 30 mm (approximately)

From the above mentioned measurements. it is known that crowns aremoderately hypsodont (perhaps a little
shorter than in R. mercki of Choukoutienl.
Comparisons ·-The character of theteeth above mentioned bears a striking
resemblance to that of the Choukoutien
R. mercki. but the size of teeth is somewhat smaller than in merclli. We have
known three species of Rhiw1reros in
Pleistocene deposits of China: R. mercki].-\GER. R. sinensis OwE;-;, and R. tidwr-

hi nus Cn·. (Coelodonta antiquitatis BLn!.).
The specimen described here is easily
distinguished from R. lic!Jorhinus CL'V.
by its smooth outer wall of crown with
Jophes sub-transvers.
The Chinese form of R. mercki was
first described as R. sp. by ZoA:-<sKY(19~8) and next by WA:-;G (1931) as a
new species: R. choukoutiensis. but in1936 TEILII.\RD de CH ..-..not:-:. refered it to
R. merd~i of Europe. This form is t\VOhorned. \\"ith a complete nasal septumand hypsodont upper and lower teeth,

(jfiJoJi N:tcAS:I wrt

and presents no yestigial upper andlower incisors. occurring widely in
Pleistocene deposits (from Villafranchian
to Loessic times) of China.
N'AollA ( 1954, p. 161 distinguished thepresent specimen from R. mercki owing
to the unaccordance of the shape of P 2.
But. as compared P2 • a detached toothbelonging to the .Musashino Kyodo-Kan
at Koganci. Tokyo. with ?VIERCK'S r~
figured by ZoA:"SKY 11928. pl. 5, fig. 82,
pl. 6. fig. 2), the writer could not recog·
nize any morphological or specific differ·ences bet ween both P!. Dicerorliinus (?)
sp. which is represented by an isolated
tooth, probably l\1 1 or f..I? reported by
SHJKAMA (19·19. p. 7-!) from a fissure deposits of Ogano limestone at KuzuO.
Tochigi Prefect. is brachyodont (shortcrowned tooth). so it can not belong to
the same species U?. mercki).
According to the descriptions of PEJ(1958, p. 32) and TE!LHARD de CHARor:-;(1936, p. 28). the distinction between R.
mercki and R. sinensis OWE:" from Sze·chuan in China is uneasy as long as themolars only are known in either species.
In R. sinensis. however, external wall of
the upper molariform teeth (especiallythe two last premolars) is not so evenas in mercld. but presenting two distinct
folds corresponding to the two internal
lophes (!\lATH. and GRA:"GER, 1923).
As external wall of P 1 of the present
specimen is almost smooth, so in thispoint, the difference is noticeable between this form and R. sinensis OwE:".
R. sinensis OwE:-.: reported by MATsuMoTo (1915) is distinguished from thisform by distinct folds on the protoloph
and the hypocone.
l\P of R. mercki
illustrated by TE!LHARD (1936, fig. 11),
l\11 and 1\P of the same species by
ZoMSJ<Y (19~8. pl. 6, fig. 4, pl. 8, fig. 2)
and one isolated specimen. l'vP refered
to R. mathi by Cu1A and CuAr (1957, pl.

~.

fig. 1) present a weak enamel sinus
or groove at the posterior wall of the
protocone, making a feeble antecrochet.
But, it is not recognized on ~p and l\Fof the present specimen. 1\Jt and l\P of
R. mercl?i illustrated by You!"G (1933,
fig. 18) and l\P and l'vf2 of R. mercki
KAcP from Les Grottes de Grimaldi(Bon.E and others. 190<i-1919. figs. 3. 5).
About the upper teeth of the Choukoutien R. mercki. TEJLHARD (1936. p. 24)
wrote: " Antecrochet and crista small.
deep-seated. sometimes vestigial, butrarely entirely absent.''
From the aboYe description. it seems,
the presence of such a enamel sinus orfeeble antecrochet cannot be a constantcharacter in R. mercki ]i\GER.
But, it is safe to say that if theChinese forms have constantly more orless recognizable antecrochet in themolars, the present specimen will be
distinguished from the Chinese fo:·m~by the lacking of antecrochet and small
dimensions of teeth.
The present teeth arc smaller thanthose of R. sineusis Owr.N from Szechuan(MATH. and GRANGER, 192:il.
As above mentioned descriptions, thepresent form seems to belong tol'vlERCK's Rhinoceros or species closely
allied to it. But, the writer wishes topreserve the precise specific name ofthis specimen till farther evidences areprovided.

References
BOULE, M .. CARTAILHAC, E .. VERNEAU, R.
& Vll.LENEUVE, L. (1906-1919):
Les
Grottes de Grimaldi. mi. 1. fasc. 3, pp.
157-362. pl. 16, figs. 2, 3, ·1, 5.
CmA. L. P. and C!Ml, ]. C. (1957) : Quaternary
Mammalian Fossils from Chihcheng,
Hopei. Vertebraht Palasialica, vol. 1. no.
], pp. 52-55, pl. 2, fig. 1.
MATSUJ\IOTO, II. (1915) : On Some Fossil

403. A Fossil Rhinoceros fmm Kuzmi. Toclzigi Prefecture
Mammals from Sze-Chuan, China. Sci.
Rep. Tohoku Ur1h'., Se11dai. Japan. Ser·. 2,
1'0!. 3, /10. 1' pl. 5. lig. 5.
W. D. and GRA;.;GER. W. (1923):

MATTHEW,

Kew Fossil Mammals from the Plioceneof Szechuan, China. Bull. .-lmer. Mus.
Nat. H:st .. z•nl. 48. art. 17. pp. 563-598.
NAORA, 1\. (1954) : Old Stone Age in Japan.
p. 16, fig. 18.
NAGASA \\"A. J. (1953) : On a :\ew Fossil
Rhinoceros from Kuzuu. jour. Geol. Soc.
japan. vol. 59. 110. 694. p. 32<i.
OwE;.;, H. (18i0): On Fossil Remains ofMammals found in China. Quart. jour.
Ceo!. Soc. Loudon. l'ol. 26, pl. 29. fig. 3.
PEl. W. C. (1958): Report on the Excavationof Palaeolithic Sites at Tingtsun. Hsiangfcnhsien. Shansi Province. China. Ins!.
Vert. Pal.. tlcad. Sin .. :Hem. 110. 2, p. 32.

SHJKA~tA,(i7

T. (1949): The Kuzuu Ossuaries.
Sci. RejJ. Tolwku Unit' .. Sendai. japan. Ser.
2, z•ol. 23. pp. 7·1-i6, pl. 5, fig. 3.
TEJL!IARD de CHARDII", P. and PJVF:TEAU, ].
(1930): Les Mammiferes Fossiles de
Nihowan (Chine). Am1. Pal., z•ol. 19.
- - (1936): Fossil Mammals from Locality
9 of Choukoutien. Pal. Sin .. z•ol. 7. fasc.
4. pp. 23-29. tig. 11.
\VA:"G. K. M. (1931): Die fossilcn Rhinocerotiden von Choukoutien. Cont. Nat. Res.
/nsf. Geol., 110. 1, pp. 69 ·84.
You;o.;c. C. C. (1933): Fossill\•Ian and Summaryof Cenowic Geology in China. Geol. A/em.,
Ser. B. 110. 5, lig. 18.
ZDA:"SKY. 0. (1928):
Die Saugeticre derQuartiirfauna von Choukoutien. Pal. Sin ..
Srr. C. MI. 5. fasc. 4. pp. 73-83.

Trans. Proc. Palaeont. Soc. Japan. X S .. No. 42. pp. 68-72. pl. lll. june 10. 1961·HI~.

A NEW SPECIES OF APHELASTER FROM THE
LOWER CRETACEOUS OF JAPAN*
KEISAI\U TANAKA
Geological Survey of Japan

and!\lA TSUTARO SHIBATA
Kyobashi Upper Secondary Chemical Schoo.
*llrfffl!~llG>f:i!E Aphe!aster 1JJ 1 ffri!: Toxasteridae HIJJ .-!phelaster r.::.:t. c.n-;:"t'l·.:.wi 7 7 :/ 7-.:t,; .t '0'..,. ;;-" ,~,. 7.117Jr$~~* Hauterivian ~il· l?i!i'HI:l-t Z>l!4~ftfl Aphel·aster iu/ege1· (GAl'TIHER) t.Jtil:~ni?:h. -n ·t.:., :;t;;#B"'Cit. :lphelaster 1.::.~-t ;;,'!llitJ;,
llauterivio-Barremian ~IJJ ril!>!ltlm!llill!~l!fl.::.ffi~-t;;, rf}r:lUt!CIJIJJ;H"ffi I'm • UJII•Jl!!fllj'/WIJJ:P~11'4 • N~hRJII~Jl!!IJJ-'PJ/ftli~:t<i.t'O'i\ft:ll!!1i17Ji\~ih11~ii·I?IBfW-t.Q. L-f.:.lf. .,-c *fll"t'IJJ»1fHI':It/i'(lllfliU.IffltJ ·I?- :lpltelaster 17J1:,1f.ltllrfl~i1 Barremian :.::. -;: -c~:N: ttit. .Q c. c il'·btv-:>
t..::.. 11*~(1)~]11. fttr?P:'Itf • tt~'l!fllJ~~l.:..t -?-clliH:>ii·I.::.~~OOci~JJIJtt:h.'O. U.:.il~--:>-c. *-lllilffllJ~Ji>d:'Wi~Jic-?•.c<lb. Aphelaster serotinus tff!r;t-['.Q. ~1?1.::.. Aphelasler ~IIil,..b~:d.:. Toxaster (Eotoxaster). Hauterivian J!!jllJ .4pfle!aster. Barremian Jllj(l) .4phelasler 17J;f:7l]l.::.:t.;ft ~d~.fili(l':ll!rfl:n• £;.:,. 13 ;,j,:ili'{IJJfif[l:t . .t I) )tfjj.., t.:il'!fl'J&>l' ,t!.;t -c~ · .Q c ~ .::t I;:> ;h.
.Q.
m 111 ~ m. ~ 111 m !!ll

*-It

*

mens were collected from the Lower
Monobegawa subgroup developed in thefollowing areas: (lJ the" Sanchu graben"in the Kwanto massif, (2) the Yuasa
district in the western part of the Kii
Peninsula. (3) the Katsuragawa basin in
the eastern part of Shikoku, and (.1) the
Yatsushiro district in \Iiddle Kyushu.
The Lower Monobegawa subgroup isreferred to the Hauterivio-Barremianstage. The subgroup called Arita formation in the Yuasa area. especially its
fossiliferous part is undoubtedly Barremian in age because of the occurrence ofammonites such as Phyl/opaclzyceras infwulibulum (n'ORBIG;>;Y), S/wsticrioceras
nipponicum MATsu~toTo. 1/etemceras sp.,
Hamulina cf. subcy!indrica D'ORBIGNY,
etc. According to the present data, theIntroduction and Acknowledgements

Although Cretaceous echinoids areoften used in zoning of the standard
areas of Europe and America, they arefound in very small numbers in Japan.
The writers have studied some toxasterid
echinoids from the Lower Cretaceous inSouthwest japan for several years. As
a result, it became clear that some ofthem are characteristic species nothitherto known from the Lower Cretaceous of Japan. They can be identified
to a new species of the genus A.phelasterfor which the specific name of Aphelasf!fr
serotinus is offered. The present speci-* Ret:eivcd Jan. 9. 1961; read at 75th meeting of the society at Urawa, l\Iay 21, 1960.
68

404.

Nezc Species of Aphelaster from the L01cer Cretaceous of Japan

genus Aplielaster occurs only from theHauterivian in South Europe, and yet it
contains no species except for A. integer(GAt:TI!IER). the type species of the genus!lpltelaster.
Therefore, it should bepointed out that the stratigraphic occurrence of AP/zelastu ranges up to theBarremian stage. judging from themorphological change in .·lp/ze/aster. it
may be furthermore suggested that theJapanese Barremian species is morphologically advanced as may be expectedof a later representative of this genus.
Thanks are due to Prof. Tatsuro
1\L\Tsn.JoTo of the Department of Geology, Kyushu University, l'vlr. Noboru
Y.-\~IASHITA of the Geological Institute,
University of Tokyo and to Mr. Yukio
YAnE of the japan Information Center of
Science and Technology for the offer ofthe materials: to i\lr ~lasahiro OKuBo of
the Geological Institute, University ofTokyo for photographing: to Dr. Haru·
yoshi FuJI~·IoTo of Yamagata University,
Prof. Wataru I!AsHI~IOTo of the Geological and Mineralogical Institute, Tokyo
University of Education and Prof. Syozo
KtsiYA~IA of the Geological Institute,
Shimane University for advice. Furthermore .. indebtedness is expressed to Prof.
Henri TER~HER, Laboratorie de Geologie,
Faculte des Sciences
Ia Sorbonne, l\lr.
Andre DEVRIES, Faculte des Sciences,
Universite d'Alger and Prof. Wyatt
Dt:RHA:\1 of the Department of Paleontology, University of California for
responses to inquiries and reprints ofliteratures.

a

Description of Species

Family Toxasteridae LA~mF.RT, 1920
Genus A.phelaster L'<~ll1ERT, 1920
Type species: Toxaster integer GAu·
TillERt)~l

The genus ilphe!aster originally designated by j. L>.~mERT (1920al was later
regarded as no more than a subgenus or
section under Toxaster rat her than aseparate genus by itself \1933!. This
genus is, however. essentially different
from any other genus included in thefamily Toxasteridae in the follo\\·ing
points: (1) the test circular in outline,(2) the frontal depression as well as theanterior notch. if any, very indistinct,
13) the petals all alike. long, continuing
to the ambitus. (4) the paired petals
somewhat flexuous. (5) the poriferous
zones all equal, and (6) the genitals 3and •I separated by the ocular IV. Of
these characters, the primitive featureof the apical system as mentioned above
is noteworthy. Such is pointed out also
in some primitive forms of Toxaster
representee! by T. africanus iCo<WA:>D)and other allied species. for which
LA~IBERT (1933) proposed a section named
kotoxaster. But, /lphe!aslt•r is distinguished from Eotoxaster by its generalfeatures of the test such as the shape,
the features of the petals and so forth.
Such being the circumstances. the writers
would like to regard Aphelasler as a distinct genus. supporting t>loRTE:>SEN's
opmion. Then attaching great importance to the primitive feature of theapical system. Aplu!laster is thought tobe closely related to Eotoxaster whichshould be thought of at least as a subgenus under Toxaster.
The species belonging to the genus.~pile/aster had. been only the two : thetype species and Toxaster tosaensis DE
LoRIOL. As to the latter, MoRTE:-ISEN(1951) states that T. tosaensis was referred to Ap/w/aster in consideration of all
petals resemblance. However, he saysthat this species tolerably differs from
Aphe/aster integer although the structureof the apical system is unknown. In

Keisalm T-LVAKrl and Matsutaro SHIB.~T;l10such circumstances. :\loJnE:-<SEN persiststhat it is too soon to include 71J.rastertosaensis in Aphelaster as L."~tBERT and
T111C:RY (19~4) do.
However. N1sJYA~IA(1954) who disagrees with the thoughtof LutBERT and Tuu~RY helieYes that
T. tosaensis is a very primitiYe form
and then proposes a new genus tobe named .·llloloxaster nvl s 'I for it. The
present writers also think that T tosa·
ensis should be remo,·cd from Aplidasterapproving of l\·ioRTE:\sE:-;'s and Ntst·
YA:>.tA's opinions.
.4plielaster has been represented byonly the type species which occurs fromthe Hauterivian in South Europe. How·
ever. discovery of a new species identi·
fied to .·lphelaster in Japan makes thestratigraphic occurrence of this genus
range up to the Barremian.
Aphelaster serotinus T A :"AK.\ andSHIBATA,

new species

Platt: 10. Figures 1-G:
Text-figures 1-2

1:vpe specimens :-Hololype, GSj. G092;
Paratypes. GSJ. fi010. GO:~s
Description :-Test of moderate size.
subcircular. rather wider than long.
widest slightly in front of the center:
anterior sulcus so very shallow as todisappear near the ambitus from which
it extends to the peristome as a very
shallow depression; anterior indentation,
if any. very indistinct. Adapical surface
somewhat inflated. highest at the apicalsystem. not truncated posteriorly; actina!
surface flattened. Apical system about
central; genital pores four in number:ocular IV meeting the madreporitc. thus
separating the genitals 3 and 4. Ambu·
lacra all alike, petaloid; petals reaching
to the ambitus. Anterior ambulacrum
located in the anterior sulcus which isvery shallow, straight. somewhat narrower than the paired ambulacra. Paired
ambulacra superficial. slightly flexuous;anterior paired ambulacra much lesstlexuous or nearly straight, diverging
at a larger angle as compared with thatof the posterior paired ambulacra which
are shortest: anterior porifernus zones
more flexuous than the posterior. thetwo zones nearly equal in width. In all
petals poriferous zones somewhat \\'iderthan the interporiferous: pore paires
composed of inner short and outer elongate pores. The ratio of the length ofthe outer pore. interval between theouter and inner pores and the length of
the inner pore is 2 : 1 : l. Paired pores
similar. not conjugate: the outer porewider and rounded at its two ends.
while narrower in the middle part: theinner pore uniform in width. its innerend bent towards the ambitus in the
middle part of the petal. but not sonear the apical svstcm. In the proximaland distal parts of the petal, the poresdecrease in length: near the ambitus
the pores similar. minute, nearly circular,
close together. set obliquely. situatednear the anterior outer corner of theambulacral plate. lnterporiferous zones
coveredwithirregularly arranged
granules.
Peristome subcircular. rather subpentagonal. shallow. about one-fourth ofthe length from the front, with aslightly emarginate labrum: plastronamphisternous. Periproct just a little
above the posterior margin of the test.
longitudinal oval in outline. Tubercles
small. perforate, not crenulate, scattereduniformly: interporiferous zones of thepaired ambulacra dotted with uniserial
tubercles, about nine in number: tubercles comparatively small in the inter·
poriferous zones of the anterior ambulacrum. No fascioles.

404.

New Species of Aplzelaster from the Lozoer Cretaceous of japan

Text·figurc 1. .·!Piidaster scrohms
TASAE.\ and Si!InATA. Apical sysLmof GSJ. 609::!: magnified.

Tcxt-tigure :!. ,·\pile/aster serotinus
and S111n.-\TA. Pore pairs inth:! anterior ambulacrum of GSJ. 6038:
magnified.

Tr\S:\K.-\.1leasurements 1 in mm. J : Spcci m~n r.:;g. na.

LengthWidth
HeightLength of thc ambul:tcr:1

GSJ GOlU
36.8
-l0.8

10.6

1

13.~

11

16.0

111
lV
\Vidth of the ambulacra
I
II

Ill
IV
Number of th:! por~ pairs
I

II
11I

IV

15.3
5.2
5.2

.t5
5.2

31
35( +)
18(+)
31( +)

Distance of apex from the anterior end
15.0

Remarks:- The present species resembles Aphelastf'l· integer (GAl.iTJIIER). thetype species of Ap/wlaster in many
points. but it is distinguishable from71

the latter by the following points. In
the species described here, all the ambulacra of which the paired ambulacra
are less flexuous or nearly straight are
more petaloid as compared with thecase of the type species; then the paired
pores are peculiar in shape. It may bealso a character for discriminating this~pecies from.lphelaster integer thattubercles in the intcrporiferous zones
are smaller in the anterior ambulacrum
than in the paired ambulacra. Further·
more. it is pointed out by LA~JBERT'1933) that Apl~elaster is closely related
to Toxaster IEotoxasler) and that theformer was derived from the latter. The
present writcrs who agree with L.... ~~3ERT's opinion can indicate some mor·
phological changes in the lineage from
Toxaster tEotvxaster) afriranus iCoQuA:-<D),
the representative of this subgenus
through Hauterivian Aplzelaster integer
to Barremian Ap/ielasler serotinus as
noted below. That is, the paired ambulaC!·a are less flexuous in the second
species than in the first and then become nearly straight in the Barremianspecies of .-lphelaster of this country.
Further. all of the ambulacra are more
petaloicl in Aphelasler semtinus than in,-!. integer and Toxaster I Eoloxaster)afrinmus. Besides. the anterior sulcus
and anterior notch are shallow in Taxaster IRotoxastcrL while they become
very indistinct or non-existing in Aplzelaster. Still, all the specimens wereobtained from muddy facies. That fact
may indicate that .lphelaster serotinus
iived in muddy layers on the sea-floor.
Ocmrrence :-(la) About 800111. south·
east of Yoshikawa. Tasukawa ·mura.
Arita·gun. Wakayama Prefecture (Yuasa
district): Arita formation; sandy siltstone (GSj. GOlO: coli. by T A:-iAKA). (1 b)
Suhara Pass, north of Yuasa-machi,
Arita·gun, Wakayama Prefecture; Arita

,..~)

1-

Keisaku T:lNAKA and Matsutaro SHWA TA

formation: sandy siltslOne (GSJ. 6038:
coli. by TA:-rAKA). (2) north of a hillcalled llachiryuzan. Takata-mura, Yatsushiro-gun, Kumamoto Prefecture: Hachiryuzan formation: shale (coli. by 1\L\Tsv
MOTO and KMtlltEHA),* (3) Tatsukawa.
Katsura-machi. Katsura-gun. Tokushima
Prefecture: Hanoura formation (coli. by
YA:-.tASIIITA), and (4) Ishida, Ohinatamura, 1\linamisaku-gun. Nagano Prefecture (Sanchu graben): Ishida formation:siltstone (GSJ. 6092 and 6093: coli. by
YABE).
Aritan epoch in the japaneseprovince, approximately
HauterivioBarremian age (Arita formation : Barremian in age).

* The specimen is probably identical withthe present species. although the featuresof the ambulacral pores can not be fully:-.scertaincd du:! to its ill-preselTation.

References
AoJ<t (NtsiYA:\tA). S. (1933): Echinodermata.
lwanamikoza. p. 50, fig. 63. (in Japanese).
LA:\IBERT, ]. (1920a) : Notes sur quelques
Echinidcs du Cretace Infericur de Ia
Provence. Notes Pro1•eucales. no. 11. p.
9. pl. 3.
- - (1920b) : Sur quelques genres nouveauxd'Echinides. Jl!emoil·es de Ia Societe academique de /'.-lube. 3 serie. tome 56. p. 14.
- - (1933) : Echinides fossiles du l\laroc.
Notes et memoires du Sen•ice de Ia Cartegeologique du 1llaroc. 110. 27.
- - and P. THIERY (1924) : Essai de Nomenclature raisonnee des Echinides. fasc. 61. p. 437.
LotHOL. P. DE (1902) : Especcs du Japon.
Notes pour sen•ir a /'elude des Echinodermes. 2 serie. fasc. 1. pp. 36-37.
l\IORTE!'SE:-1. Tu. (1951): Monograph of theEchinoidea. 110/. 5, pt. 1. pp. 355-356,
figs. 252-253.
~ISIYAMA. S. (1954): Echinodermata. KoBA·
YASHI's Koseibutsugalm (l'aleonlology). vol.
1, p. 350. (in japanese).

Explanation of Plate 10
Aphelaster serotinus TA:>AKA and SIIIBATA. new species
Figs. la-b. 1a, Adapical surface. X 1.2. lb. Actina[ surface, xl.2. lshido formation. (Holotrpe, GSJ. 6092).
Figs. 2a-b. 2a. Adapical surface. xl.2. 2b. Actina[ surface. X 1.2. A rita formation. (Parat)'pe, GS]. 6010).
Figs. 3a-b. 3a, Adapical surface. x1.5. 3b. Ad::tpical surfnce. x3. (External mould). Arita
formation. (Paratype. GS]. 6038).
Figs. 4a-b. 4a. Adapical surface. X 1.2. 4b. Actina! surface. X 1.2. Ishida formation. (GSJ.
(i0Y3).
Fig. 5. Ada pica I surface. xI. II::moura formation.
Fig. 6. Adapical surface. x 1. IIachiryuzan formation.
All specimens here illustrated are internal moulds unless otherwise stated.

TANAKA and SHIBATA: A New Species of APhelaster

Plate 10,/~,.... . . . ...

~-·.~····:~~-

2a

\
6 \

I

\

'

Trans. Proc. P<>.:acont. Soc. Japan. :\. S .. :\o. 42. pp. 73-78. pl. ll, June 10. 1961

4oii.

ON SOME CONSlDERATIO~ OF THE MOLLUSCAN FAUNAFROM THE ASAGAI FORMATION*SABURO KANNOTokyo University of Educationt.Hlf~~HII::fi~'f:.:.-?l·"CO)-~~: .::.tt ~"CQ)fi)f~;.::.J:::, c tl(.tl iWJ~ ll~lt~t1H~t.:.jlt.... *~t.c~~~iFi"~O)c ~.tL"C~t.:."

1'"

~··

~

•,•

L.t.J•r..f-.::.O)!!(P-tJtl'~~t1JO)J\B-t-H l· :/;fJL-O)tll~ ffO) ll tift.: Pilar (Pitari11a) matszmwtoi(NAGAo) t.c~Ui.:. Soletellina (s.s.) kobiyamae KA:-;;-;o, n. sp. t.ccO)J¥i:/j*O)J.'l.ftTI~

r1!ft~D!~O)WP.i.:.f*-*<5Jt t..:Hft-fiO)rp:.:.:t.

~ ll{;.:.1!; "'-·L'~. r...: !:. n:-nn·--> t.:..
.::.h 1::>0) ·1~ :J: n· Gi:lHtlWJ¥g'lt''J\O)~-r-53K~It#: t... -c~tt;
f£. \, 0)-(::t..f.ctJ •"'>f..:,: C fdtf~'L. f..:o'i"\' Jf ~ f!Jl

Introduction
The molluscan fossi Is collected by tvlr.
II. Ko11JY.\:\IA from the Yakatoka tunnel(i\ f3 l:l ~ :/ ;(- ~~, which is now being
constructed along for the joban I ine
about 500 meters north of the Yotsukura station llmft.~j. were sent to thewriter for examination.
The fossils
were determined to comprise Yoldia
asagaiensis
l\hKIYA:\IA.
Venericardia(Cyclocardia) tokunagai YoKOYA~IA, Pilar(Pitari11a) matsumotoi (NAGAO'. Papyridea/wrrimani DALL. Solete/liua kobiyamae
KA:o::-;o, n. sp .. Mya 1..-lrenomya) ;.;retcingki!VlAKI r AMA, Periploma besshoense (YoKo·.YA~L"' 1, Crepidula auricula YoKOYAMA,
Jlmpulina asagaiensis l\L\KIYMIA, andColus asagaiensis ?-.1.'\KIYA:o.tA.
It is noteworthy that the present fauna
includes Pitar (Pitarinat matsumotoi andSoletcl/ina kobiyamae IC,:-;:-;o, n. sp.,which are recorded for the tirst timefrom the Asagai formation. l'vloreover.
Pitar (Pitarina) matsumotoi is originallyrecorded from the Ashiya formation of+* Received Feb. 23. 1961 : read at the annual
meeting of the society at Tokyo. Jan. 15, 1961.

north Kyushu and subsequently known
to occur from the \Vakkanabe formationof 1-Iokkaido.
The writer here expresses his thanks
to Prof. Wataru HAsiiJ~toTo of our Insti·tute, and Prof. Kotora HATAI, Instituteof Geology and Paleontology, Tohoku
University, for their continued en·couragement. Thanks are also due to
Mr. Hajime KoBIYA~IA for kindly offer·
ing his collection to the writer for study
and for his kind collaboration in thefield. The writer extends his thanks to~,lr. Atsuyuki MIZt·:o:o. Geological Surveyof japan. for his permission to examine
the molluscan fossils collected from the
Paleogene formations of no1·th Kyushu
now preserved in the Survey.

Geology of the Vicinity of
the Yakatoka Tunnel
The present molluscan fauna was collected from about 10 meters above thebase of the Asagai formation at about
100 meters north of the southern entranceof the Yakatoka tunnel. Here the Asagai
is superposed on the Iwaki formation
with conformity. The lwaki comprises

Saburo KAN.VU
sandstone and conglomeratic sandstone
and its uppermost has coaly shale or anearly one meter thick coal seam.
The Asagai formation preserves abun·dant molluscan fossils whereas the coalseam of the uppermost part of the lwaki
yields some plant fossils as Musopllyllum
sp., Sabaliles sp. and others.
Among the molluscan fossils. almost
all of the pelecypods were found innatural position (1;-;o:-.tATA and HtGUCHI.
1955, p. 291. especially, Mya L4.renomya:
grezcingki occurs parallel to the bedding
plane and in natural position.
Characteristics of the Asagai Fauna
The geological age of the Asagai for·mation has been discussed by many
workers such as TtcHA;-.;owtTscH (1909),
YoKOYAMA <1924). i\lAKIYA:-.IA (1934).
HATAI and ~ISIYA:'\IA (19.t9), IIATAJ and
ICutADA (1950). and HmA YM.tA (1955)
from the stand-point of the molluscan
fossils, while AsA;-.;o (1949) stated hisvie,..,· on the basis of the foraminiferal
fauna. Many of them conclude that the
Asagai belongs to the upper Oligocene
or Aquitanian (l'viAKJYA:-.IA: IIIRAYA:'\1.-\),
middle Oligocene or Rupelian (}-[.uAJ
and KA:-.IADA) or Oligocene (1\sAl'>o:
H.-\TAI and NtstYA:-.IA).
~vloreover, all workers have expressedthe \'iew that the thermal condition of
the Asagai fauna is a typically boreal
or cold water type based upon the mol·luscan and the foraminiferal genera in
the Asagai fauna. The molluscan genera
as Cycloamlia, Lincyma, Thyasim, .·lncis·
trn!epis, Huccimtm, Aulacofusus and L\1ar·garites range in the· northern Pacific,
namely, north of Hokkaido, and extend
along the west coast of North America
down to Oregon and California. AsANo(19-19) noticed that the Asagai assemblage is of cold water judging fromElphidium asagaiense AsANO, and E.
yumoloense AsA;-;o, which resemble somespecies widely distributed in the Arctic
seas.
The marine Eocene fauna of Kyushu
comprises such foraminifers as JYummulitc·s and Discoc_vclina, and such molluscs as Orthaulax and :lthleta, all ofwhich are inhabitants of the tropicalregions. The Eocene flora of the lshikari group contains such genera as
Saba!iles and ,\Jusophyl/um which resemble some genera now widely distributedin the tropical to subtropical regions.
The marine Oligocene faunas of Japan
excepting for the Asagai comprise tropical to subtropical elements. namely, Area,
Crassatellites. Pilar, Callista, Turritella,
Phalium, Cypraea. Co~tus, and nautiloids.
These molluscan genera seems to be in·habitants of rather warm temperatecondition.
The l'vliocene marine fauna includes
larger foraminifers as Lepidncyclina and
Miogypsina as well as molluscs \\·hicharc characteristic and widely distributedin the tropical to the subtropical areasin the world. Moreover, the so-called
Kadonosawa fauna of middle 1\liocene
age in Japan shows features characteristic of the subtropical type. However,the Kadonosawa fauna is replaced by
the Yama fauna IOn'KA, 1943) and theT6geshita fauna (HAsHJ~IoTo, 1950) which
are characterized by the mixture of inhabitants of cool and warm waters.
In the Pliocene the marine fauna ischaracterized by rather cool inhabitants.
Shortly speaking, during the Eocene
to Oligocene, the marine climate of the
Pacific coast of Japan estimated fromthe marine fauna and flora was rather
warm and shows tropical or subtropicalcharacteristics excepting for the Asagai
fauna. Such conditions seem to continue
to the middle 1\liocene of japan. \Vhile405.

11ioltuscan Fauna from the Asagai Formation

it had started to shift south or thatwarm climate and replaced by rather
frigophilic ~cold limited) fauna during
the upper 1vliocene to Pliocene. Accord·
ingly. the discordance arises among thecharacteristics of the Asagai and theother Oligocene faunas in Japan. From
the abovement ionecl reasons. the Asagai
fauna should be re-examined from theview-point of the thermal condition. The
new occurrence of Pilar tPitarina} matsu·
motoi and Soletelliua kobiyamae may serve
to interpret these inharmonious phe·nomena.
Pilar (Pitari11a) matsumotoi is known
to occur from the Yamaga and the
Sakamizu formations {Oligocene) of the
Ashiya group in northern Kyushu. The
Yamaga and the Sakamizu faunas com·prise the inhabitants of rather warm
waters. In addition. the recent speciesof the genus Pilar is distributed fromthe equator to N. lat. 36° along the
Pacific coast of Japan.
Fourty molluscan genera have beenreported from the Asagai formation, of
which 11 genera are distributed in thearea ranging from the equator to northof N. lat. 70' along the Pacific coast ofjapan. namely:-39'
GlycymerisLimao·-·10'Laet•icardium o·-33'
00-:?5'
Papyrideao·--12·lJosi11ia
o·-.t6'
Jfactra() 0

Tel/ina
Soletel/i11a
Calypt raea
Turritetla
Epilolliumo•-noo· !)J•
0'·35'
IJ'-35'0'-39°The Asagai fauna. indeed, comprises
abundant molluscs such as Com:/wcele.
Liocyma. Venericardia, 1Hya. 1Hm:s.;arites,_·'wlacojusus, and Buccinum. all of which
distribute rather in the northern Pacific.
HoweYer. the presence of tropical or
subtropical elements should be consider·
ed to interpret the paleoclimate esti·
mated by the fossil fauna. DurHIA~l

15

1.1960. p. 4) stated " the presence ofthermophilic organisms seems to bemuch more important than the presenceof cool tcater elements. but their signifi·
cance must be supported by evidence
1.such as growth stages) that they lived
lin the sense of completing a life cycle)
where found", and .. within the marine
environment frigophilic organisms canusually find suitable temperatures indeeper water within the same region,and they are thus not significant interms of the regional climate". For
instance. as cited by Dt:RHAl\1 (1950), thegastropod Fusitriton oregouensis which iscommon in intertidal area from Puget
Sound to Alaska is found only in deeper
water off southern California.
Thesame case was pointed out by NARt:SE
11952) and the writer (1960. p. 152) based
upon the distribution of the genus.!!ncislrolepis along the Pacific coast ofjapan. namely. Ancistrolepis o/dwtensis
0,\LL which had been collected from off
Sakhalin (N. lat. 48 ) from 109 fathoms
and .·1. troc/wideus C0ALL) from off Yoko·hama <N. lat. 33'' l from 600 fathoms.
On the other hand. paleoclimaticstudies along the Pacific coast of !\orthAmerica are being progressed by many
workers as Dt:RiiAM (1950. 1960). CHA;-.;EY(1940). Dor~F (1955), and B.\RGHoor~:-~ ( 1953).
based upon the distribution of the marine
fauna and tlora. Floras and faunas of a"subtropical " type extended much further poleward in the northern hemis·
phere during the early Tertiary than atpresent. llowever. they gradually re·treated towards the tropics during thelater Tertiary.
The climatic changes during the early
to late Tertiary agree with one anotheron both Pacific coasts of japan andNorthwest America. The conclusion on
the basis of the new occurrence of Pitar
and Soletellina leads us to the opinion

Saburo K:tNSO

7(ithat the Asagai fauna is not a boreal
fauna but a subtropical to temperateone.

Reg. no. (illG.
Famil~r

Veneridae

Genus Pilar Ru~tER, 1857

Description

Subgenus Pitaritla Jt:KEs· BRow:-;, 1913

Family Carditidae

Pilar (Pitarina J matsumotoi(NAGAO), 1928

Genus Venericardia LA~IARCK, 1801
Subgenus Cydocardia Co:-;I{AD, 1861

Fenericardia (Cyc/ocardia) tokmwgai
YoKOYA~IA. 19~4

Pl. 11. Figs. 1-3

tokrmagai
YoKoYAMA,YoKOL\l\IA: four. Col/. Sci. Imp. Uttir.

1924. Venericardia

Tokyo. t•ol. 45. art. 3. p. 18. pl. 3. figs.
10-12.

195 ). Venericardia(Cydocardia) toktmagci
Sci. Rep. Tokyo
Uni1•. Et!r.c:Ition. sec. C. ro/. ·1, no. 29,
p. 89. pl. 2. figs. II, 1!J. :w.
1!!60. Venericardia(Cyc/omrdia) lolumagai
YOKO\'A~IA. HIRAYA~IA:

Yoh:OYA~IA.

OYAi\IA.

l\I1zu:-~oandIll. Haii(//J. f ap.. Paleog.
Moll .. p. 151, pl. H. lig:;. 7a-c.

SAKA~IOTO:

Remarks:- The present species was
originally reported by YoKOYAMA fromthe Asagai formation distributed in
Hirono·mura, Futaba-gun, Fukushima
Prefecture. HoweYer, the type specimens
are so meager that some confusion arises
as to specific determinal ion. The sup·plementary note is given as follow:
The outline of the shell exhibits con·siderable variation, namely, one is ob·liquely trigonal and the other shows
rather rounded shell. and intermediate
forms between them exist.
Surfaceornamented with about 25 radial ribs
which are slightly elevated. round-topped
and separated with round-bottomed,
shallow grooyes. When the outer layer
is missing. the ribs show distinctly
angular, flat-topped radials.
Growthlines sinuate on the ventral border.

Pl. 11, Figs. 4-8
1928. Pi/aria malsumoloi NAGAO. NAGAO: Sci.
Rep .. Toholm Imp. Uniz• .. ser. 2. vo/. 12.
no. 1, p. 73. pl. ll. fig. 17 : pl. 13. figs.
'1-G.
1940. Pilar sp. Kt;RosE: Mem. Fac. Sci. Eng ..
Waseda Unit·., no. 13. pl.-fig. 5 (nodescription).
1952. Pilar(s. s.)
matsumotoi (!\AGAO).
l\lrzt:~o:Tnms. Proc. Palaeont. Soc.
]apa11. N. S .. 110. 6. p. 192 (no. fig.).
1!!55. Pilar cf. matsumoloi (NAGAO). Vozn11:
Dil/u .. no. 19, pp. 78-79. pl. 12. figs. 1. 4.
1956. Pilar malsumotoi (NAGAO). HIRAYAMA:
S'd. Rt'/>. Tokyo U11it•. Education, sec. C.
vol. 5. no. 45, p. U.!, pl. .J. fig. 15.
1960. Pilar matsumotoi (NAGAO). OYAMA.
M1zu;-;o, and SAKAMOTO: Ill. Handb.
f ap. Paleo/f. llioll., p. 184-185. pl. 57.
ligs. la·c.

Remarks:- The present species was
originally described by ~AGAO from the
Yamaga formation of the Ashiya groupin northern Kyushu. The specime.ns at
hand are similar in outline to theholotype of the named species and arecharacterized by having transversely
quadrate·ovate shell, eYenly convex
postero-ventral end, slightly concave
antero-dorsal margin, faintly archedpostero-dorsal border. and nearly hori·zontal, short. and triangular pallial
sinus.
According to NAGAo's original descrip·
tion, there is a faint groove-like depres·sion extending into the shell at a distanceof one-third of the length of the shell.

405.

lvfo/luscan Fauna from the Asagai Formation

However. the present specimens ha\·c
hardly no groove-like depression anddeeper pallial sinus. and thicker shell.
These differences seem to depend upon
the state of fossi I preservation.
The present specimens are so wellpreserved that their hinge structure
can be observed as follow: Hinge teeth
consisting in the right valve of a strong
middle cardinal. a rather strong posteriorcardinal. a thin anterior one which areconnected with one another making anarch and an anterior socket, and in theleft valve of a large posterior cardinal,a thinner cardinal in front and an elongate anterior lateral.
The present species has been reported
from the Yamaga formation (upper
Oligocene) of the Ashiya group and its
correlative in northern Kyushu and the
Wakkanabe Eocene in Yubari City in
Hokkaido (Cozu~u. 1955). However, thelatter specimens seem to be not conspecific with the named species because
they have rather straight postero-dorsal
margin. more rounded ventral border,
more pointed narrow pallial sinus, andweak hinge teeth.
Reg. ~o. 6117.

Family Asaphidae
Genus Soletellina BLAII'\'ILLE, 182-!
Subgenus Soletelli11a s. s.

Soletellina (s. s.) kobiyamae KA:-;:-;o, n. sp.
Pl. 11. Figs. !J-12

Shell moderate in size, equivalved, in·equilateral, compressed. ovate-rectangularin outline; beaks rather inconspicuous,anterior to the middle: antero·dorsal
margin short. gently convex, turned
into broadly rounded anterior end: posterior dorsal margin long, nearly straight:

~-

1 I

Yentral border rather straight merging
into widely arched or somewhat truncated posterior margin, making blunt angle
between the postero- and postero-dorsal
margins. Surface of shell coYered byfine, irregular lines of growth. Nymph
plate missing. Hinge teeth consistingin the left valve of a small. but distinct
anterior cardinal and thin and week posterior one : the anterior cardinal more orless bifid; hinge plate of a right valve
inaccessible.
Pallial sinus deep andAnterior muscle scar rather
wide.
rounded, the posterior somewhat narrowand elongated.
JHeasureme11fs :-ca. 65 mm in length :45 mm in height; 14 mm in thickness of
intact valves (holotype).
Comparison :-Soletellina (Nuttalia) ezo·
nis KuRoDA et lL\IlE (1955, p. 17, pl. 1,
figs. 12-13). a Recent species of the
Pacific coast of eastern Hokkaido, ismore or less akin to the present one.
but differs therefrom by having equivalved shells. widely rounded ventral
margin and sloping postero-dorsal border,and narrowly rounded posterior margin.
Soletellina minoensis YoKOYA!'IA (1926. p.
221. pl. 28. fig. 14) from the Tsukiyoshi:tvliocene of Gifu Prefecture somewhat
resembles the present species, but theformer differs from the latter by having
more elongate. thick and lower shell.
Remarks:-The genus Soletellina BLAr:-;\'JLLE. 1824, has been reported from the
Miocene in Japan, thus the present occurrence seems to be the oldest in ourcountry.
Reg. Nos. 6118 (holotype): 6119 (paratype).
References
AR,\1, ].

and 1\A:-.::-.:o. S. (1~60): The Tertiary

System of the Chichibu B:osin, Saitama·Prefecture, Centr:J.l ]ap~.!1. P:trt II, pp.

78

Saburo KANNO
1~3-3~'1i.

AsA:-;o, K. (HI-HI) : Foraminifera from the
As:1gai fcrmation (Tertiary) of Fukushima Prd;;cture. Jap:;n. }our. Pal .. 1'0/.
23. 110 . •5. pp. -173--!78.
DURIIA:\1, J. W. (1950) : Cenozoic marine
climate of the Pacific coast. Bull. Am.
Geol. Soc .. l'ol. 61. pp. 1243-121i6.
- - (1960): Paleoclimate. Physics aud Chemistry of the Earth, 1'0/. 3, pp. 1-16.
HABE, T. (1955): Fauna of Akkeshi Bay.
Pub!. :lkkeslzi Marine Biological Station.
110. 21' pp. 1-31.
H.-\T.-\1. K. and KA!\1.\D.-\. Y. (!950): Fossil
evidence for the geological age of th~
Cchigo group. Joban coal-field. Short Pap.
lnst. r;eol. Pal., Tohoku Unil'., 110. 2. pp.
58-7-1.
HIRAYAi\1:\, K. (1955): The As:tgai formationand its molluscan fossils in the northern
region of Jo-ban co;,l.field, Fukushima
Prefecture. Japan. Sci. Rep .. Tokyo t:.:niv.
Education. sec. C. m/. 4. no. 29, pp. -19-130.
- - (1956) : Tertiary molluscs from Hikoshima, Yamaguchi Prefecture. japan.
with remarks on the geological age ofthe "Ashiya fauna". Ditto., zYJl. ,:;, 1/(J.
.J!i, pp. 81-127.
1:-;o:\IAT.-\, T. and HIGUCHI. Y. (1955): Fora-

minifcral fauna from th:! Asagai formation of Yotsukura-machi. Fukushima
Prefecture. (in Japanes2). l'1ikochu (TheForaminifera). no. .J, pp. 29-3·1.
.:\IAKIYA:\IA. ]. (193-!): The Asagaian molluscs of Yotukura and l'vlatchgar. ,l/em.
Col/. Sci .. Kyoto Imp. l..inil'., ser. B. t•ol.
10. 11o. 2. art. 6. pp. 1~1-lGi.
N:\GAO. T. (19~8) : Paleog.zne fossils of theIsland of Kyushu. Japan. part 2. Sci. Rep ..
Tohoku Imp. U11iz• .. ser. 2. z·ol. 12, no. 1.
pp. 11-140.
OYA:\IA. K .. .MJzu:--;o. A. and SAKA:\IOTO. T.
(1960): Illustrated handbook of Japanese
Paleogene molluscs. Geol. Sun•. Japan.
SUG:\1, K.. ~IATSl:J. H.. SATO. s.. KJT.-\GA\\'A,
Y.. S,\SAI<J. .M.. 1\'!JYASIIITA, M. and
1\AWACHI, H. (1957): Geological maps
and explanatory text of the Joban coalfield. Geol. Sun·. Japan.
Uozr::-.11. S. (1955) : On some molluscan
fossils from the Paleogene ·wakkanabe
formation in Hokkaido.
Trarzs. Proc.
Palaeout. Soc. japan. X.S .. 110. 19, pp. 73-80.
YoJ..:OYA\IA, lVL (1934): 1\!olluscan remains
from the lower part of the Joban coal-field.
lour. Coli. Sci. Imp. Uni1•. Tohyo. l'ol. ·15.
art. 3, pp. 1-22 .

Explanation of Plate 11(All figure5 in natural size)
Figs. 1-3. Venericardia (G'yclocardia) tokzmagai YoKOYA\IA
Fig. lb. Showing the cardinal teeth of lig. la.
Fig. 3b. Showing the apical Yiew of fig. :b.
Figs. .t-8. Pitar (Pitarinu) matsumoioi (~AGAO)
Figs. 7-8. Showing the cardinal teeth of left and right ,-alvcs.
Figs. 9-1~. Soletellina (s. s.) lwbiyamae KA:"-1:-;o, n. sp.
Fig. 9. Holotype.
Fig. 10. Paratype.
Fig. 11. Showing the hinge teeth of a left val\·e.
Fig. 12. Showing the outer sJrface of shell.

K ANNO :Molluscan Fauna from the Asagai Formation

S. AoKI photo.

Plate 11

Trans. Pro..:. Palaeont. Soc. Japan. N. S., :\o. 42. pp. 79-87. pl. 12. June 10, 1!'61.tOG.

A FIND OF MONOTJS (ENTOMONOT!Sl FRO~VI

EASTERN YAMAGUCHI PREFECTURE. JAPA~*AKIRA HASE
Institute of Geology and Mineralogy. Faculty of S..:icncc.
Hiroshima Uni\·ersity

111 p l)j',JI(g.j;.t IJ Mono/is (Entomrmotis) 0)9eji: Ill P ~~~;!?(JnJ1l1>~;frJIIIJr!•J:tiiiO):jt)j*'J 1 km
O)J1!!.~.i.~·o?<5::-,t-:i.:.lif;:filL.t.: Manolis (Entom01:otis)

fl.:~ rb!iO).JE~:.:.-?t ·-tlllli1!-t0,

Introduction and Acknowlcdgl'ments

The Upper Triassic (Norian) Mono! is(Entomonotisl was recently discoveredfrom the siltstone exposed at a new
wavside cutting, about 1 km. north ofJ'vl~kaihata. :\liwa·cho, Kuga-gun, Yama·guchi Prefecture •sec Text-fig. 1). Sev·
era! fossil specimens were at first sentme by ~v[r. rvlakoto Stii:\IAOKA of r..liwa
Middle School. Subsequently, manywell-preserved specimens were collected
and the geology was investigated bymyself assisted by some members ofHiroshima University. The area aroundthe locality is mainly occupied by thelate Paleozoic strata named the Kugagroup, and is situated between the twometamorphic zones in the Inner Zone ofSouthwest japan, the Sangun and the
Ryoke (KoH;~.tA & OKA:<.IVRA, 1952; KoJtr--tA.
1953: N t.:REKt. 19601. Therefore. the dis·covery of Jfonotis (Entomonotis) seems
to be of significance for the analysis of
the geologic history of this district. In
this paper I describe two species of thegenus from the above-mentioned locality:* Received Mar. 3, 1961 ; read at 72nd meet·ing of the society at Hiroshima. Feb. 14, 1959.

0) 2 '@li~;}CJ!{i;L. <lt>h-\!"-t..:;_-O)i1!!'l'.t!Uf

* -tt

:rt

one is identical to the Siberian species.
J11onotis (Entomonotis) tyPica (KrJ>.\Rrsov '' l.
and the other represents a new species.
Brief notes on geology are also given.
I wish to express my sincere thanks toProfessor Tatsuro MA-rsu:~.toTo of Kyushu
University and Professor Sotoji btA~tl:I{Aof Hiroshima University for their advice,encouragement and kindness of reading
the typescript. i\Iany thanks are also
due to Dr. Koichiro lct!IKAWA of Osaka
City University for his valuable sug·gestion. to Professor Teiichi KoBAYASHI
and Dr. ltaru HAYAJ\11 of Tokyo Cniver·sity for their help. to Professor George
KoJI:o.tA. !-.lr. Kei Hmr-:, Dr. Mitsuo l\.\KAI':oand Dr. Terukazu NuREKI of Hiroshima
University for their help and criticism,and to Messrs. Kazuo OKAMOTo and
Tsuruo YoKOYAMA of the same univer·sity for their assistance in collecting
Finally, particularfossil specimens.
thanks are due to Mr. 1\lakoto SHtMAOKA
of Miwa !\'Iiddle School, who showed me
the fossil locality.
Repository: All the specimens de·scribed in this paper are kept in theInstitute of Geology and Mineralogy,
Faculty of Science, Hiroshima University.
Hiroshima. Japan.

A.kira H-!S!~S!l

Tcxt·fig. 1. bdex map of the loc:•.lity
of .llonotis (Entomonotis).

l:-:-:·:·1 .Honotis (Entommwtis) beds (Upper

J.--1 Lenticular limestone
m.
0

500

1000

IIIIIll Banded chert
1:::: 3Shear-slate with sandstone

Triassic)

Kuga group] (Permian)and conglomerate

Text-fig. 2.

Geological map of the Mukaihata area.

Paleontological Descriptions
Class Pelecypoda
Family ::vionotidae
Genus Mono/is BRo:-~N, 18301~vpe-species :-Pectinites

salinarius
1820, by subsequent designation by Hr-:RR.\1.-\:-l:o-;sE"' (1852).

ScHLOTHEI~'·

Subgenus Entomonotis l\lARWICK, 1935

Type-species (of the subgenus):1\Ionotis richmondimza ZITTEL, 1864, byoriginal designation.

Mono/is (£ntomonotis) typica(KIPARISOVA)
Pl. 12, figs. la, b, 2-11

1!132. Pseudomonotis
scutijormis
TELLER.
KIPARISOVA, Trans. Ceo/. Prosp. Serv.,
U. S. S. R .. jasc. 111. p. 21, pl. t figs.
14-18.
1936. Pseudomonotis scutiformis var. typica
KIPARISOVA, Trm1s. tlrctic lnst., t•ol .
.'10, p. 118, pl. 1. figs. 6. 7, 9, 10.
1954. Pseudomonotis (Entomrmotis) scutijormis
var. typic:a, KIPARISOVA, Field atlas of
the jau11a a11d flom of the Triassic jornwtions in Primorskij /\raj, p. 38. pl. 29.
ftgs. 7-9.
1958. .llonotis (Entomonotis) typica. IcmKA WA, Palaeontograpllica, t•of. 111. pt.
A, fasc. 5-6. p. 180.
~~·pes :-Pseudomonotis scutiformis var.
typica was established by KIPARISOVA(1936) on syntypes, of which four were
illustrated (pl. 1. figs. 6. 7, 9. 10). I havenot seen the actual specimens.
J1aterial :-Among a hundred and more
specimens collected by K. limE, T.

406. Find of Monotis (Entomonotis) from Eastern Yamaguchi Pref.
NcREKI. K. Q,,,.,.~JoTo, T. YoJWYA:\1.\ andmyself. the comparatively well preserved
ones are IGSH-HA 3~1A-C, 322A. B. 323.
3~41\-C. 325A, B. 3~fi-336, :~37!\, B, 338A,
B. 339, :HO. 34L\-C and 34~!\-D {rightvalves. 321-332, 341B, C. 3428, C, D: left
ones, 333-340. 341!\. 3·!2A).
Diagnosis :-Shell of moderate size.
oblique·oval in outline, but sometimes
nearly circular. somewhat longer thanhigh or almost as high as long. inequivalw. somewhat inequilateral, roundedin front. slightly or considerably produced postero-ventrally.
Left valve
moderately inflated. most convex near
the center of the valve: right valve
weekly convex or almost fiat except theumbonal area.
Hinge-line about 2/5 as long as theshell-length. Postero-dorsal margin fairly long, straight, forming an obtuse
angle with the posterior margin: posterior wing rather well developed but
ill·defincd. triangular, flattened or slightly
concave: posterior margin long. nearlystraight or sometimes slightly concave.
forming a rounded angle with the ventral margin, which is long. arched andpassing insensibly into the well rounded
anterior margin: anterior wing small,rounded. not well defined. Byssal car
small but distinctly projected obliquely
upwards from the umbo of the rightvalve. with a slit-like byssal notch
beneath.
L'mbo of the left valve rather large,
prominent, strongly incurved, prosogyrous. projected considerably beyond
the hinge-margin, situated at about 2/5

Specimen : IGSII-IIA
321A (right vaiYe)
321B (
do.
)
322A (
do.
)
323 (
do.
)
326 (
do.
)

81

to 1/3 the length of the shell from theanterior end: umbo of the right valve
smaller and less elevated than that of
the left, pointed. slightly projected above
the hinge-margin. :\ ridge extending
from the umbo towards the postero·ventral corner. at first distinct and thengradually flattened.
Surface-ornament similar in the twovalves. consisting of numerous radialribs of two orders !rarely three orders).
besides the concentric growth·lines andundulations. l~adial ribs almost straight.
but in the anterior part curved upwards.
as broad as or somewhat narrower than
the nearly tlat interspaces, well defined,
moderately prominent, round-topped,
narrower and more closely set on boththe anterior and posterior sides than on
the median area. having a tendency to
be weakened towards the posterior, but
still distinct on the posterior wing: ribsof the second order. which appear usuallyin the middle growth-stage, becoming
almost as strong as the primaries in thelater stage: fine and short ribs of thethird order infrequently inserted near
the periphery: the total number of theribs, inclusive of those on the posterior
wing. about 40 to 55, predominantly
about 45 to 50. Radial ribs crossed byfine, rather regular, crowded concentric
growth-lines and several irregularly developed concentric wrinkles or folds.
1'1ensurements :-The specimens at handare often too much deformed for the
precise measurement.
The following
dimensions are mostly based on less deformed specimens.
Length (mm.)!!eight (mm.)

26
21. 5

21
22

22

17.5

31. 5
32

34
38.5

A/lira HAs!~·
331
do.
)
33:.!
do.
)
333 ( left valvl" )
334 (
do.
)
335 ( left va!Ye. immature)
3HB (right valve. immature)

Remarks :-From the above-describedcharacters, the specimens before me
are identified to :l1onotis (Entomonotis)
t:ypica (KtrARrsovA), which has been re·ported from the Upper Triassic of East
Transbaikalia. Werchojansl<. the Kolymalndigirka Land and the Maritime Province, all in East Siberia.
The secondary deformation preventsme from examining the variation of theshell-outline and the inflation. In JGSHIIA 321A (Pl. 12. fig. 1a. b) and IIA 321B
(Pl. 12. fig. 2). both of which seem to be
scarcely deformed. the ratios of thelength to the height are 1.24 and 0.98
respectively.
The intercalation of the ribs of thesecond order is generally not so conspicuous as in the syntypes of Kri'ARtsovA(1936, pl. 1, figs. 6, 7, 9, 10). In the immature specimens and eyen in some of
the adult ones [c. g. JGSH-HA 337B (Pl.
12. fig. 6)]. the radial sculpture consistsof the primary ribs only, with thesecondary ribs infrequently inserted near
the periphery. In certain other examples[e. g. IGSH-HA 339 !Pl. 12. fig. 7). HA
341 A (Pl. 12. fig. 9). HA 341C (Pl. 12. fig.
8)] a secondary rib appears in every
interspace between the primaries, andthus they are quite similar to the Siberianform. All the specimens at hand werecollected from one and the same locality
and are intimately connected in one
morphic series. It is. accordingly, unwarrantable to divide them specificallyor subspecifically.
Judging from the internal moulds, theinner surface of the shell reflects the

25

21

2.t

~2.5

27.5
26
14

19.5
20
13
13

li

radial ribs and concentric folds of theouter surface. The inner surface of theposterior wing is almost smooth. The
byssal ear is well observable in IGSHJ-1 A 329 (Pl. 12. fig. 11 ).
"Pseudomonotis" scutifomzis var. typica
KrrARrsovA (1936, p. 118) has been ranked
by IcHIKAWA (1950, p. 19: 1958, p. 180)
as an independent species. As KrPARI·
sovA stated. this is clearly distinguishedfrom l'rlonotis Wntomonotis) stutiformis(TELLER) (1886. p. 125, pl. 19. fig. 3a, b)
by its more oblique·oval outline. more
weakly differentiated radial sculpture
and ribbed posterior wing. None of the
1\lukaihata specimens approaches thatspecies. Therefore. I agree with lou·
K.\ 11 A in separating the two forms spe·cifically. This species differs also from
"Pseudomonotis" scutiformis var. ko/ymica
KrPARrsovA (1936, p. 120. pl. 1, tlgs. 8. 1114) in number and arrangement of theribs.
In the shell-outline and the radial
sculpture of two orders which covers
the whole surface inclusive of the posterior wing. 1lfonotis (Entomonotis) typica
is closely allied to M. (£.) jakutica(TI,LLER) (1886, p. 124, pl. 17, figS. 16a. b,
17, 18: KtPARISOVA, 195 1, p. 46, pl. 35,
fig. 6) from \'Verchojansk and other areasof East Siberia, but the ribs are finerand more numeroljs in the former thanin the latter. .M. (E.) oclzotica densistriata(TELLER) (1886, p.. 119, pl. 17, figs. 7, 8,
13a, b, 14: pl. 18. figs. 9. 10; KonAYAsHI& icrHKAWA, 1949, p. 253. p\. 9, fig. 15),a well-known Norian subspecies distri·buted in Japan and Siberia. resembles
1

406.

Find of Manolis (Entomonotis) from Eastern Yamaguchi Pref.

the present species in the number ofthe radial ribs, but has a larger shelland a nearly smooth posterior wing
which is rather well defined from themain part of the shell. Moreover. theribs of that subspecies are of threeorders. !11. (H.) multistriala (KoBA Y ASill
and IcHIKAWA) (1949, p. 255, pl. 9, figs.
11, 12 ?, 14) from the Norian in the
Sakawa basin in Shikoku, japan, isanother resembling species, but has lessnumerous and less differentiated ribs.
M. (E.) typim differs from M. (E.) suf,.
rydoidea (Kon ..w:\SIIi) (1935, p. 29, pl. 7,
fig. 1) from the Kamosho formation in
the western part of Yamaguchi Prefecture in outline of the shell, which sug·gests that the latter might be conspeciflc
with M. (E.) srutiformis. ·Orwrrence :-About 1 km. north of
Mukaihata. Miwa-cho, Kuga-gun, Yamaguchi Prefecture. This species is widelydistributed in the Norian of East Siberia,
and has been reported (but not fully de·scribed) also from the Kitakami Ivlassif.
Northeast japan.

iHonotis (En/omonotis) mulwihalensis
IIAsE n. sp.

Pl. 12. figs. 12a. b, 13a, b.
H-16. 17a-c. 18

Material :-Holotype, IGSH-HA 311. aleft valve (Pl. 12, fig. 12a. b). Paratypes,
IGSH-HA 312, a left valve (Pl. 12. fig.
13a, b); IGSII-HA 313, a left valve !Pl.
12, fig. 14); !GSH-1-IA 314, a left valve(Pl. 12. fig. 15); IGSH-HA 315, a left
valve (Pl. 12, fig. 16); IGSH-HA 316.
conjoined valves of immature stage (Pl.
12. fig. 17a-c). Several other comparable
specimens are also available to me. All
were collected by K. 1-lmr:, T. Nt.:REKI,
K. 0K,utoTo. T. YoKOYAMA and myself.

8:~

Din~nosis :-Shell of moderate
size.
oblique-oval in outline. longer than high.
somewhat inequivalve. highly inequiIateral, short and rounded in front, prolonged postern-ventrally.
Left valve considerably inflated, mostconvex ncar the center of the valve:
hinge-line about 1/3 to 1/4 as long as
the shell-length: postero-dorsal margin
short. nearly straight, forming an obtuse
angle with the posterior margin;posterior wing small, triangular, notwell defined: posterior margin long,
weakly curved, gently descending andthen bent forwards into the ventral
margin, describing a semicircle: ventral
margin long, arched, passing insensibly
into the well rounded anterior margin:
umbo of moderate size. strongly convex
and incurved. projected considerably
beyond the hinge-margin. situated atabout 1/4 to 1/5 the length of the shellfrom the anterior end: beak prosogyrous:a ridge extending from the umbo towards the postcro-ventral corner, at first
distinct and then becoming obsolete.
Right valve similar to the left in outline. but less inflated. provided with asmall spiniform byssal ear which is projected obliquely upwards from the umbo:
antero-dorsal margin excavated beneaththe ear to form a deep sinus; umbo
smaller and less elevated than that of
the left. projected a little above thehinge-margin.
Surface-ornament consisting of several
irregularly spaced concentric wrinkles
or folds of unequal strength and fainttraces of radial ribs, the latter of which
are entirely obsolete on the umbonalarea.
J11ensurements :-Owing to the secondary deformation, the precise measurement is difficult.
Some specimens
measure approximately as follows.

Akira J!!ISE ..

84
Specimen
IGSH-HA

LengthHeight

(mm.)

(mm.)

311 (left val\'e)
do.
313 (
)
316 (conjoined valves,immature)

36.5
29.5
16

26
23.5
14

Remarlls :-The holotype specimen.
which seems to be scarcely deformed.
is about 1.4 times longer than high.
About 15 radial ribs are countable onits. antero-ventral area, which are low
but rather distinct. closely set, uniform
in strength and almost as broad as theinterspaces. There are about 10 indis·
tinct traces· of ribs on rat her broad
area of the posterior half. The radial
sculpture on the rest of the surface isalmost effaced.
In IGSH-l!A 316 (aparatype, immature) about 25 ribs arecountable along the antero- and posternventral margins of the right valve.
While the concentric undulations are
distinct on both the external and internalmoulds. the radial sculpture is very
obscure on the latter.
The present shell can undoubtedly bereferred to Mo11olis (Eulomcmotis) by its
outline. inequivalve shell and distinctly
projected byssal ear with a deep byssal
notch beneath. the last of which is wellobservable on the right valve of IGSHIIA 316 (1'1. 12. fig. 17a-c).
Among the species of Mono/is (Eutomonotis) hitherto described from theUpper Triassic in Japan and East Siberia,
M. (E.) zabaikalica (KlPARrsovA) (1932. p.
30. pl. 2. figs. 12, 13 ; 1936. p. 80, pl. 1,
fig. 5; I<onAYASHl & lciiii<AW.<\, 1949, p.
257, pl. 10. figs. 12-20; synonym: Entomotis kurosawai SAKAGUCHI. 1939. p. 229.
pl. 15, figs. 1-6) has the closest re·semblance to M. (E.) mukailtatensis in
the oblique-oval outline. the strongly
convex left valve and the retrogressive
radial sculpture. In M. (F.) zabailwlica

Thickness
(mm.)
8

7
3. 5+2. 5zabailmlira. hbwever, the effacement ofradial sculpture is more evident than inthis species: the whole surface is almost
smooth except for the concentric undulations. In M. (f.:.) zabaika/ica semimdiatalcHIJ<AWA, 1958 (=E. zabaikalica var.
i11/emu:dia KoBAYASHI & lcuiKAWA, 1949.
p. 25R. pl. 10. figs. 19, 20), the distinct
ribs are on the umbonal area, while near
the periphery they are obsolete. The
reverse is the case in the species inquestion. In this respect the present
species is wry similar to 1\l. (E.) sublartJis (TELLER) (1886, p. 125, pl. 19, fig.
2a, b) from Werchojansk. but is distinguished by its smaller posterior wing
and shorter hinge·margin.
"PseudomoJIO/is" sp. nov. described by KrPARI·
so\'A (1936. p. 117. pl. I, figs. 1-3) fromthe Kolyma-Indigirka Land also resembles
this in surface-ornament, but the radialribs are more obsolete and the posterior
wing is larger in the former than in thelatter.
llfonotis routhieri AvrAs (1953, p. 11:~.
pl. 25, fig. 4) from the Upper Norian or
the Rhaetian in New Caledonia and JH.
calllala MARWICK (1953, p. 58. pl. 6. figs.
21, 22, 26) from the strata of the sameage in New Zealand are also character·ized by the retrogression of the radial
M. (E.) mulwilwlmtsis is easily
ribs.
distinguished from the former by its
smaller size and much more conspicuousconcentric folds. and from the latter by
its narrower and more numerous tracesof ribs on the peripheral area.
On:urrence :-About 1 km. north of
Mukaihata. fvliwa-cho, Kuga-gun. Yama-

406.

Find of Mono/is (Enlomonotis) from Eastern Yamaguchi Pref.

guchi Prefecture. Here. the present
species coexists with but is much lessabundant than l'.lonotis (Entomrmotis)

typica.
Geological Notes

Both the late Paleozoic strata and the
Mono/is (l·~ntommzotis) beds distributedin this area take the general trend of
E-W and incline apparently monoclinallyto the north with variable angles. but
the structure is by no means simple(see Text·fig. 2). The Triassic strata
seem to be inserted in the Paleozoic
shear-rocks as a small "Schuppc ". The
thrust faults which cut off the former
from the latter run in a direction of
NGOo± W, dipping to the NNE with anangle of 50-60°.
The Triassic strata are composed exclusively of siltstone. The siltstone isblack to dark grey in color. massive tothickly stratifkd and sometimes sandy.
with laminae of fine sandstone. Microscopically. the silt grains in clay matrix
arc usually subangular, with abundantquartz and minor amount of feldspar.
Sericite flakes arc also abundant. In
some cases the siltstone is calcareous.
The thickness of the outcropping strata
is 10m. or less.
The Paleozoic formation, that is apart of the Kuga group, is composed of"shear-slate" with subordinate sandstone
and banded chert. Layers of conglom·
crate and lenses and nodules of lime·stone occur at horizons. The shear-slate
is black in color. often containing teared
blocks of sandstone. which are fusiform
and are arranged along the shear-plane.
It is cut obliquely by innumerable slaty
cleavages. The sandstone is also sheared to some degree. The chert is milky
to dark grey and thinly stratified. The~omplicated inlraformaljonal folds arc:85

common in it. The pebbles of the conglomerate are chiefly those of sandstoneand subordinately those of chert. lime;;tone and rhyolitic rock. Angular fragments of slate are also often contained.
By the occurrence of Yabeina sp.* froma limestone lens near Naguwa. about
5 km. west of Mukaihata, the Kugagroup of this area is assigned to the
Permian. as suggested by KoJIMA and
0~-;A~IIIIIA (1952) and KnJI~rA (1953).
The Triassic rocks have also sufferedfrom the shearing: the sandstone-laminae
are teared in some degree and are cut
by oblique cleavages. But the shearing
is not so strong as in the Paleozoic slate.
The stratigraphic distribution of thespecies of Monotis (l•:ntomonotis) has
been well studied in the southern 1\itakami !vlassif in Northeast Japan. According to lcnrKAwA (l950, 51. 54. 58) and
0:-lllKI and BANDo (1958), .M. tf\'.) typica
occurs from the basal member of theupper Saragai formation, which is referred to the Lower Saragaian substage.
KIPARlsovA (1932, 36, 54) regarded theage of this species in East Siberia as
Upper Carnian, while NAK,\ZA\\'A (1958)
and lcniKAWA (1958) considered it to be
Lower Norian.
.M. (E.) mukailwtensis n. sp. is closely
allied to M. (E.) zabaikalica. KJI'ARJSOVA
considered that the age of the latter
species in Siberia is younger than thatof M. (E.) typira. Similar relation has
been observed in the Kitakami ~lassif,
where l'vl. (E.) zabaika/ica occurs fromthe uppermost Saragai formation, thatis the Upper Saragaian substage. In
New Zealand and New Caledonia, thespecies with retrogressive radial sculp-* The material was collected by 1\h.
lVIasatora KAWAI of the Geological Surveyof Japan. For the determination l am in.
debted to Mr. Kimiyoshi SADA of Hiroshima
University.

8flAkira HASE

ture (Mono/is calM/a MARwtct.;, 1953; M.
roulhieri AvtAs, 1953) have been reported
from the Rhaetian and (or) the upper·
most Norian (the strata above the M.
(E.) riclmwndiana beds).
Such being the case, it is an interest·
ing fact that the smooth species M. (E.)
mukailwtensis coexists with the mull iple·
ribbed species .M. (E.) /ypica. Recently,
TuTscuKov (1955. after Zenlralbla/1 f.
Geologie u. Pa!iiontologit•. Teil 2. 1956, p.
160) has offered an opinion that thelower part of the Norian in Northeast
Siberia is characterized by M. (E.) smti·
formis, M. (E.) typica and 11-1. (E.) zabaifwlica. As M. (F;.) typjca predominates
over 111. (H.) nmlwihalensis, the Mo11otis(Entomonolis) beds of l\1ukaihata are
more probably assigned to the Lower

Saragaian (Lower Norian) than to theUpper Saragaian (Upper Norian). andare possibly correlated to the Kamosho
formation in the western part of Yamaguchi Prefecture.
Heferences
A \'lAS, J. (1953) : Contribution a )'etude
lllratigraphique et palE)ontologiquc desformal ions antecretacees de Ia NouvelleCaledonic Centrale. Sci. Tnre. Nancy, 1•ol.
1. 11os. 1-2. pp. 1-271i. pis. 1-26.
JcJJII<AWA, K. (1950): Chronological classilicatinn of the Triassic Period in Japan(in Japanese with English resume). ]our.
(;eo!. Soc. ]apall, r•ol ..56, 110. 652. pp. 1722.
- - (1951): The Triassic formations in thesouthern part of the Kitakami Massif

Explanation of Plate 12(Figures of natural size, unless otherwise stated)
Mono/is (Entomonotis) typica (Kti'ARISO\'A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 80
Fig. l. Internal (1a) and external (1b) moulds of a right valve. IGSH-HA 321A.
Fig. 2. Internal mould of a right valve. IGSH-HA 3218.

Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.
Fig. 9.
Fig. 10.
Fig. 11.

Left valve. IGSH-IJA 333.
Right valves. IGSH-HA 322A 11nd B.
Internal moulds of right valves of immature stage. IGSII-IIA 324A, B and C.
Internal mould of a left valve. lGSH-HA 337B.
Internal mould of a left vai\'C. IGSII-HA 339.
Internal mould of a right valve. IGSII-HA 341C.
Internal mould of a left valve. IGSH-HA 341A.
Internal mould of a right valve. IGSH-IIA 323.
Internal mould of a right valve, showing the byssal car, x5. IGSH-HA 329.
J1follolis (E11Iomo11ofis) mulwi/zafellsis liASE n. Sf> . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . • . • . . . . . . . p. 83
Fig. 12. Internal (12a) and external (12b) moulds of a left valve. I-Iolotype, IGSH-HA 311.
Fig. 13. Internal (13a) and external (13b) moulds of a left valve. Paratypc, IGSH-IIA 312.
Fig. 14. Internal mould of a left valve. Paratype, IGSH-HA 313.
Fig. 15. Internal mould of a left valve. Paratype, IGSH,HA 314.
Fig. 16. Internal mould of a left valve. Paratype, 1GSH-HA 315.
Fig. 17. Internal (17a, b) ancl external (17<.:) moulds of conjoined valves of immature stage.
17b, showing the byssal car of the right val\'e, x5. Paratype. IGSH-HA 316.
Fig. 18. Internal mould of a left valve of immature stage. IGSH-J-IA 317.
All specimens carne from a wayside cutting. about 1 km. north of Mukaihata. Miwa-cho,
Kuga-gun. Yamaguchi Prefecture (Coli. K 1-ltL>t-:. T. NuREI<I, K. Ot<AMOTO. T. Yoi<OYAI\IA &A. HASE).

H ASE :I

I

Monotis (Entamonotis)

Plate 12406.

Find of Mmwtis (Entmnonotis) from Easter11 Yamaguchi Pref.

(in Japanese). Rep. Spec. Number (Triassic
stratigraphy of japan), Geol. Sun•. Japan.
pp. 7-23. pl. 1.
- - (1954) : J'v!orphi<; change observed in
the history of Entomonotis from Japan(in Japanese).
Bioi. Sci. (Seibutsu·
Kagalm). evo!utional vol., pp. 43-46.
- - (1958) : Zur Taxionomie und Phylogenie
der triad ischen ·· Pteriidae " (Lame IIi·branch.). mit bcsonderer Berucksichtigung dcr Gattungen Claraia, Eumorplwlis,
Oxyloma und "Umzotis. Prdaeontographiw,z·ol. 111. pt. A, fasc. 5-6, pp. 131-212, pis.
21-:!-1.
KII'ARISOVA. L. (1932):
Contributions tothe stratigraphy of the marine Trias ofEastern Transbaikalia (in Russian withEnglish resume). Trans. Geo/. Prosp.
Sem. U.S. S. R., fasc. 111. pp. 1-33, pis.
1-')

- - (1936) : Upper Triassic pelecypods fromthe Kolyma-Indigirka Land (in Russianwith English resume).
Tra11s. .-\relic
Ins!., l'ol. 30. pp. 71-136, pis. 1-5.
- - (195·1) : Field alias of the fauna and florar~(

the Triassic formations in Primorskij
Kraj (in Russian). 52 pp., 35 pis., Moscow.
Kou.-\Y,\SIIl. T. (1935): Einige neue triadische Bivalven a us der lnnerwne Slid west·
Japans. fap. four. Geol. Geogr.. zoot. 12.
/lOS. /-2. pp. 27-32, pl. 7.
- - & lciiiKAWA, K. (1949): Late Triassic"Pscudomouotis" from the Sakawa basinin Shikoku. Japan. Jap. ! our. Geol.
Geogr., ,,of. 21, 110s 1-·1, pp. 245-2u2. pis.
9-10.
KoJI.\IA. G. (1953): Contributions to thc.
knowledge of mutual relations between
three metamorphic zones of Chugoku
and Shikoku, Southwestern Japan, withspecial reference to the metamorphic andstructural features of each metamorphic

~one.

87

four. Sci. Hiroshima Unit•.. ser. C.

t.•ol. 1. no. 3. pp. 17-46.
- - & OKAMUHA, Y. (1952):

Yrmai district,guide-book of the geological excursion (injapanese), Ill pp .. 1 pl., Dept. Geol., Fac.
Sci .. Kyushu Univ .. Fukuoka.
MAI<WICK. ]. (1953): Divisions and faunasof the Hokonui System (Triassic andJurassic).
New Zealaud Ceo/. Surv ..
PaletmtoJ. Bull., no. 21, pp. 1-141, pis. 1-17.
NAKAZAW1\. K. (1958): Correlation of theUpper Triassic System between Japanand Maritime Province (in Japanese).

Jour. (Jeo/. Soc. Japan, t•ol. 6·1. 110. 750.
pp. 161-ltJ3.
NuREKI, T. (1960): Structural investigationof the Ryoke metamorphic rocks of thearea between lwakuni and Yanai. South·
western Japan. ]our. Sci. Hiroshima U11iz•..
ser. C. tJo/. 3. 110. J, pp. <i9-l4l, pis. 8-13.
01\UKI. Y. & B,\i"Do, Y. (1958): On the
Saragai group of the Upper Triassic
System (Stratigraphical and paleontologi·
cal studies of the Triassic System in the
Kitakami Massif, Northeastern Japan:1) (in Japanese with English resume).

jour. Ceo!. Soc. Japan. 1'01. li.f, no. 757.
pp. 481-493.
S,\KAGUCHI, S. (1939) : A new species ofE11/omolis from the Upper Triassic of
the Kitakami Mountainl:md. jubilee Pub/.
Commcm. Prof. YABE 60111 Birth., z·ot. 1,
pp. 227-231. pl. 15.
TELJ.ER, F. (1886): Die Pelccypoden-Fauna
von Werchojansk in Ostsibirien. fn E.
v. MoJSisovJcs: tlrktische Triasfmmeu.

A/em. ;lead. imp. Sci. St. P<'tcrsbourg. ser.
7, z•o/. 33, uo. 6, pp. 103-137, pis. 17-20.
Tt:TSCHKOV, I. I. (1955): Ober Pst!rtdomrmolis·
Faunen der norischen Stufe in Nordost·
sibirien (in Russian). Doldacly Akad.
Nuuk U.S. S. R .. vo/. 1 0·1. pp. 508-610.

88

PROCEEDINGS OF THE PALAEONTOLOGICAL SOCIETY
OF .JAPAN*

n 6·1:~?f:~t# 78 fliJfflil.'lt. 1961 iF 5 fl 13.
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. . . . . . . . . . . . . . . . . . . . . . Koichiro MASUDA~'li 31 ~)oo A Jf.f iii! (5 JJ 13 m
Fossil Ailanthus from Miocene flora of Ilok·kuido ................................. .
. . . . Toshimasa TANAI & Nobuo SuzuKI
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. . . . . . . . . . . . . . . . . . . . Kiyoshi T AKAIIt\SHI
On the evolution of the Osmundaceae ....
.............................. Scido E:-<DO
A new species of the genus Clisiop!Iyllum
from the Upper Carboniferous of the
Ehime Prefecture. Southwest Japan (fl:;~) .. Kenichi IsHII & Nobuo Y ..-..MAGIWA
Lower Permian Bryzoa from Miharano of
the Taisbaku limestone plateau, south·
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...... Tciichi KOBAYASitl & Eiji INoUE
Notes on Sleinmamwlla ( Yelmrella) aimumtt(Yabe & Nagao) (fi:;~Jl:) .. l\litsuo NAKAi'O
On some new gastropods from the Kishima
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. . . . . . . . . . Tugio SuuTo & Yoshio UtmA
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A Fossil Rhi11oceros from Kuzuii, Tochigi
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Colloquium on Miocene Flora of Japan(5 H 14 13)

Miocene Flora of Southwestern Ilokkaido,
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.... Toshimasa TA:-:AI & Nobuo SuzuKI'N~~ ti~ U ~II iJtl!.U) m=:*t! g.lli'I~H::E~'1(1)~Jf:

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