ISSN 0031-0204

a -It",1;-±~~~• .t-. iz.f

Transactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 113

Palaeontological Society of Japa n
April 30, 1979

Co-Edito rs
Associate editor

Itaru I-IAYAMI an d T s un e masa SAITO
Tomow o Oza w a

Officers for 1979-1980

Honora ry President:
President:

Te iichi KOBAY ASHI

Tetsuro HANAI

Councillors : Ka zuo AS AMA, K iyotaka CHINZEI, Takashi HAMADA, Te tsuro HANAI,Ita ru HAY AMI, Hisay osh i IGO, Kame tos hi K ANMERA, T a mio KOTAKA, Tat s uro MATSUMOTO, Iku w o OBATA, Tsunemasa SAITO, Tsug io SH UTO, Yokich i
T AKA YANAGI, Toshi masa T ANAl, Ry uzo T ORIY AMA
Members of Standin g Committee:

Kaz uo A SAMA (Finance), K iyotaka CHINZEI(General Affa irs), T akashi HAMADA (Plan ning), Ita ru HAYAMI (Transa ctions),
Hisayoshi IGO (F oreig n Affairs), Ikuwo OBATA (Me mbersh ip), Tsune masa
SAITO (Tr a nsac ti ons), Tsugio Sl-IUTO (S pecial Pape rs), Yokichi TAKAYANAGI("F oss ils")
Secreta ries : Hiromich i HIRANO and Yasumitsu K ANIE (M embershi p), K unihiro ISHIZAKI (" Fossils"), To mo w o OZAWA (Transactions), Tosh iy uki YAMAGUCHI(General Affairs), Juichi YANAGIDA and Ienor i FUJIYAMA (Special Papers)
A udi t or:

Sumio SAK AGAMI

The f ossil on the cove r is Nippon itella explicata HANZA WA, a n aberr a n t
uncoiled f usulina cean fro m t he Lowe r Permia n Sa kamotoza wa Formation,
sou thern K itaka mi, Northeas t J apan .

A ll communicati ons r ela ting to this Journal sh ould be addressed to t he
PA LAEONTOLOGICAL SOCIETY OF JA PA N,
c/ o Business Center for Acad emic Societies,
Yayoi 2-4- 16, Bunkyo-ku, Tokyo 113, Japan .
Sole agent : Unive rsit y of Tokyo P ress, Hon g o 7-3- 1, T ok yo, Ja pan.

Trans. Proc. Palaeont. Soc. japan, N.S.; No. 113, pp. 1-14, pI. 1, April 30, 1979

698. SOME LATE EARLY CRETACEOUS PLANTS FROM FUKUIPREFECTURE, IN THE INNER ZONE OF JAPAN*
T ATSUAKI KIMURA and JUNjI HORIUCHITokyo Gakugei University, Koganei, Tokyo 184

Abstract. This· paper deals with the palaeobotanical descriptions of the following newly discriminated species from the Chinaboradani Formation: Cfr. Osmundopsis efimoviae, ? Osmunda sp., Gleichenites nipponensis, Coniopteris dr. arctica,
Birisia onychioides, Asplenium dicksonianum, Onychiopsis elongata, Podozamites eichwaldii and Coniferae sp. These species as well as those described by KIMURA(1975) constitute the Tamodani Flora, the youngest flora lacking angiosperms in
the Inner Zone of japan. judging from the available information about the Tamodani Flora, this flora would be characterized by the predominance of ferns including such younger types as Coniopteris dr. arctica, Asplenium dicksonianum etc. andby the rarity of cycadophytes. The fern composition of the Tamodani Flora isclose to the coeval floras in Siberia and is different from the coeval Wealde"n-typefloras in the Outer Zone of japan.

ably overlie the Akaiwa Formation consisting mainly of sandstone with intercalated shales, and in the type area areoverlain unconformably by the Upper
Cretaceous Omichidani Formation consisting of alternation of tuff, sandstoneand shale.
The Omichidani Formation containing
rich angiosperms, is similar in rockfacies to the Kitadani Formation and its
equivalents, ~ut the latter lacks angiosperms.
Except the Omichidani Formation, such
tuffaceous layers have only been known
in the Kitadani Formation and its equivalents in the Tetori sedimentary sequence. In the Kitadani Formation andits equivalents, fossil plants have been
known from the Uppermost Formationof the Tamodani Group and the Chinaboradani Formation.
In 1975, KIMURA subdivided the 'Tetori
Flora' stratigraphically into the Kuzuryu

Introductory notes
The uppermost formation of the Lower
Cretaceous part of the Tetori Supergroupconsists of alternation of tuff, shale andsandstone, and is sporadically distributedin the Inner Zone of japan as follows;
along the Omichidani and the Takinamigawa valleys on the border (type area)of Ishikawa and Fukui Prefectures (Kitadani Formation, MAEDA, 1958); along theupper course of Tamodani valley, Fukui
Prefecture (Uppermost Formation of
Tamodani Group, KIMURA, 1975); andalong the Uchinamigawa and the Itoshirogawa valleys, Fukui Prefecture (partly
in Gifu Prefecture) (Chinaboradani andOyama Formations, MAEDA, 1957a, b).
The stratigraphic sections of these areas
are correlated with each other in Fig. 1.
These tuffaceous formations conform* Received August 22,. 1978; read June 3·,
1978 at Tsukuba.

1

Tatsuaki KIMURA and Junji HORIUCHI

2(bite Jurassic), the Oguchi (early Neocomian), the Akaiwa (late Neocomian) andthe Tamodani (Aptian) Floras (in thesense of stratofloras). Therefore, theTamodani Flora, including the plantsfrom the Chinaboradani Formation, isthe youngest one without angiosperms
in the Inner Zone of Japan.
Recently one of us, HORIUCHI collectedmany fossil plants from the Chinaboradani Formation. They are poorly preserved, but the best preserved specimens
are described here together with additional information about the Tamod~niFlora.
Previous work
KIMURA (1975) described the following
species from the Uppermost Formation

I§~ An400[::::2"1 Tf
M!:@U SS
•

1

Sh

Om

of Tamodani Group (on the right are therevised names accepted in the presentwork).
Osmundopsis ? sp.
= Osmundopsis sp.
Gleichenites aff. porsildi =G. porsildii
Arctopteris sp.
Jacutopteris sp.
Adiantites sp. A=Adiantopteris
sp. A
Cladophlebis ex gr. denticulata
C ..efr. pseudolobi/olia
Sphenopteris kochibeana
Sphenobaiera ? sp.
Ginkgoidium ? sp.
Podozamites sp. dr. eichwaldi= P. eichwaldii= P. lindstroemii
Pityophyllum sp.
Conites sp.

Fig. 1. Correlative columnar sectionsof the upper part of. I to shiro Group, the Tetori Supergroup.
1 : along the Omichidani valley (after MAEDA, 1958).
2: along the Chinaboradani and the Itoshiro·
gawa valleys (compiled by us from MAEDA,
1957a) .
3: along the Nobudani valley (Oyama area),at the upper course of the Itoshirogawa valley (after MAEDA, 1957b).
4: along the Tamodani valley (after KI~mRA,
1975) .
KU: Kuwashima Formation. AK: Akaiwa
Formation. (AK): Equivalents of the Akaiwa Formation. KI: Kitadani Formation. OM:
Omichidani Formation (Upper Cretaceous).
CH: Chinaboradani Formation. OY: Oyama
Formation. UM: Uppermost Formation of
the Tamodani Group. Sh: shale. 5s: sandstone. Tf: tuff; Qp: quartzporphyry. An:
andesite.
In the Oyama area, the tuffaceous conglo·
merate Formation (the Nobudani Formation
by MAEDA, 1957b; 10-28 m thick) underlying
the Oyama Formation and overlying unconformably the Palaeozoic System, might be
included in the Oyama Formation, although
MAEDA (1957b) correlated the Nobudani Formation with the Akaiwa Formation.

698.

Late ea1'ly Cretaceous plants

In addition to the above, MATSUKAWA
collected Nilssonia sp. from the same
locality.
The Tamodani Flora (stratoflora)

The genera and species from the Uppermost Formation of Tamodani Groupand those newly recognized from the

Chinaboradani Formation are shown in
Table 1. The species from the two
localities are listed and Podozamites
eichwaldii alone is common to both
localities.
This flora is different in composition
from the coeval floras in the Outer Zoneof Japan, and is also different in somefeatures from its underlying floras in

Table 1. The list of species (Tamodani Flora) from the equivalents of Kitadani
Formation, the uppermost formation in the Itoshiro Group, the Tetori Supergroup.

CH!I SI -r~Cfr. Osmundopsis-eft.-n-zo-v-ia-e-S-A-zv-n-·L-IN-A------------ - - 0
Genera & species------

Localities

I™
i/-;;:-'--

1o. sp.

0? Osmunda sp.

Gleichenites niPPonel!si~-O-IS-H-1- - - - - - - - - - - ---0;

I:::,.

0II

I:::,.

0I!,;

G. porsildii SEWARD

II:::,..

o I 1:::,.1

Coniopteris dr. arctica (PRYNADA) SAMYLI;\;A
Birisia onychioides (VASSILEVSKAJA & KARA-MuRSA) SAlVlYLlNA

0-A-sp-l-e-nl-·u-m-d-i-ck-s-o-n-ia-,-!U-n-~-H-E-E-R-------------- - -- - -A rctopteris sp.
Jacutopteris sp.
Adiantopteris sp. A
Cladophlebis ex gr. denticulata (BRONGNIART) NATHORST
C. dr. pseudolobifolia VACHRAMEEVSphenopteris kochibeana (YOKOYAMA) OISlII
Onychiopsis elongata (GEYLER) YOKOYA~I~"

A

L..>

.

I I:::,. ,O!I-;;:-I---10'1:::,.
oI:::,.
oI:::,.
oI:::,.

oooI:::,.

I:::,.

s p . - I e l - - ! ' - ; ; : - I. .--1-Sphenobaiera? sp.
I0 I : I
Nilssonia----------------------

I:::,.

Ginkgoidium? sp.
Podozamites eichwaldii SCHIMPER
Pityophyllum lindstroemii NATIIORST
Conitessp.

Coniferae sp. (catkin-like cone?)____ ,~ _ _ I~

o
o
o

__

o

o

TM: Uppermost formation of the Tamodani Group (KI:\1URA, 1975).
CH: Chinaboradani formation (present work) ; • not described.
SI : common or allied species to those in the coeval floras in Siberia, NE-China andMongolia.
RY: common or allied species to those in the coeval floras in the Outer Zone of. Japan.

Tats~taki KIMURA

4

the Tetori Supergroup, as mentioned
below.
Ferns.
This flora is not a member of theWealden-type floras in the Outer Zoneof japan, but a member of the Tetoritype floras characteristic of the Inner
Zone of japan, because this flora contains such Dicksoniaceous ferns as
Coniopteris dr. arctica and Birisia onychioides, and does not contain Matoniaceous ferns characteristic of the early
Cretaceous floras in the Outer Zone ofjapan (KIMURA & HIRATA, 1975; KIMURA, 1976).
2) The species of ferns as seen in theunderlying Oguchi and Akaiwa Floras,
are absent in this flora.
3) Osmunda-like ferns and Asplenium.which are considered to be younger
elements in the early Cretaceous, arefirst recognized in this flora and neitherof them has so far been found in theunderlying floras.
4) So far as the fern composition isconcerned, the Tamodani Flora is different from the coeval Wealden-typefloras in the Outer Zone of japan, butvery close to the early Cretaceous floras
in V AKHRAMEEV'S Siberian Palaeofloristic
Area. Fern genera in the Tamodani
Flora such as Coniopteris, Birisia, Asplenium, Arctopteris, Jacutopteris and some
Cladophlebis (e. g. C. dr. pseudolobifolia)
are common in the early Cretaceous
floras in the Siberian Palaeofloristic
Area, but have not been found in theearly Cretaceous floras in the Outer
Zone of japan.
However, the Tamodani Flora does
not correspond fully to the coeval Siberian floras, because in this flora, Gleicheniaceous ferns are fairly abundant,
especially in the Oguchi Flora, while inthe· Siberian floras, they are rare and1.

1)

and Junji HORIUCHI
only sporadically known, the same istrue for Onychiopsis.
5) Fern genera such as Osmunda,
Osmundopsis, Asplenium and Arctopteris
are also common in the late early Cretaceous floras in the Siberian Palaeofloristic Area.
2. Cycadophyte. The only cycadophyte
found in the Tamodani Flora is undetermined Nilssonia. Cycadophytes areabundant in the underlying floras.
3. Ginkgos. Only two forms are known
in the Tamodani Flora. They possibly
belong to Sphenobaiera and Ginkgoidium.
No ginkgo-leaves have been found in theearly Cretaceous floras in the Outer Zoneof japan, except for a doubtful record(OISHI, 1940, p. 368, pI. 38, fig. 4 regarded
by him as Baiera brauniana) .

4. Conifers.
1) Broad-leaved conifers are only represented by Podozamites eichwaldii which
occurs fairly commonly. No specimen
referable with confidence to Podozamites
has been found in the early Cretaceous
floras in the Outer Zone of japan. Podozamites leaves recorded by previous
authors from the Lower Cretaceous plantbeds in the Outer Zone of japan, are
now referable to Cycadolepis or Nageiopsis (KIMURA & KANSHA, 1978).
2) The only narrow-leaved conifer is
Pityophyllum lindstroemii, of Pinacean
affinity, which has not been found in
the early Cretaceous floras in the Outer
Zone of japan. Both Podozamites eichwaldii and Pityophyllum lindstroemii are
fairly common in the Siberian early
Cretaceous floras. Furthermore, two
incomplete coniferous cones are known,
but their identification is still uncertain,
because of their poor preservation.
The interesting point of the small flora698. Late early Cretaceous plants
described here is, first that it is the
youngest flora lacking angiosperms in
the Inner Zone of Japan and second thatit resembles to the Siberian flora but isdifferent from the coeval floras in theOuter Zone of Japan.

5

thickened, dehiscence by a longitudinal
stomium. Spores rounded with triradiate scars.
Cfr. Osmundopsis efimoviae SAMYLINA
PI. 1, figs. 1-2; Text-figs. la, b

Acknowledgements

We first express our sincere thanks toProfessor Emeritus Thomas M. HARRIS,
F. R. S. of the University of Reading forhis very helpful suggestions and kindest
reading over the present manuscript.
We also give our thanks to Miss Tamiko
OHANA, a graduate student of the Tokyo
Gakugei University for her kind help in
drawing the figures in this paper.
Systematic description

Unfortunately neither cuticles nor organs are preserved in the present
material. The specimens here described
are all peposited in the Department of
Astronomy and Earth Science's, Tokyo
Gakugei University. 'Qsmundales
Osmundaceae
Genus Osmundopsis HARRIS, 1931a: 136
This genus was first proposed' by
HARRIS (1931a, p. 136), for the Osmundacean leaves, instead of OsmU1idites.
The diagnosis given by him (1931b, p.
48) was emended also by him (1961, p.
99) as follows; sterile and fertile leaves
dimorphic. Sterile leaf bipinnate, aCladophlebis., Fertile leaf as a wholelanceolate, bipinnate or tripinnate withno lamina, ultimate branches filiform,
bearing groups of sporangia. Sporangi,apear-shaped, wh,Qle apical regiop. of wall

Comparable specimes:
Osmundopsis efimoviae SA:VIYLINA; 1964, p. 50,
pl. 3, figs. 1-3; text-figs. 3a, b (Buor-Kemyuss Formation,' Zyrianka Coal-Basin).
Cladophlebis sp. a (pars); OISHI, 1941, p. 171;pl. 36, figs. 2, 2a (non figs. 1, la) (Lo-tzuKou Series, NE-China).

Description: Many sterile pinna fragments were obtained, two of which were
illustrated here (PI. 1, figs. 1-2).
Sterile frond is at least tripinnate, butwhole shape is uncertain. Ultimate pinnae are long and narrow, typically 2.3
em long and 0.5 em' wide at base, narrowing gradually towards the acute apex,
attached to the axis at an angle of 45
degrees, flexible, sometimes falcate andbearing 11-12 pairs of small sized pinnules .. Pinnules ,are, set closely, kat adromic in order, deltoid in form, with,obtusely pointed, apex, entire and contiguous at base; the upper margin is
generally straight and the lower, one
rounded as shown in Text-fig. lao Mid-,nerve is distinct, persisting to the tip
and sending off typically 4-5 pairs of
simple secondaries at wide angle asshown in Text-fig. lb. (The fructification
has not been found).
Remarks: The present fern is characterized, by its deltoid pinnules which arecontiguous each other at base and withsimple secondaries.
The present fern, although its fer.tile
part has not been found, resembles externally the sterile leaves or:iginally des-,cribed , by" SAMYLINA as Osmundopsis
efimoviae (pI. 3, figs. ,1-3) from theTatsuaki KIMURA and J'ttnji HORIUCHI

6

Zyrianka Coal-Basin. But the present
pinnules are somewhat different fromthe Siberian ones with acutely pointed
apex and with twice forking secondaries
on the lower half of midnerve. Then
we treat the present fern as Cfr. Osmundopsis efimoviae.

The fertile fragments described by
KIMURA from the Tamodani Group (1975,
pI. 5, figs. 2-5; fig. 4-a, b) as Osmundopsis?
sp. are like those of SAMYLINA'S Osmundopsis efimoviae, but the associated sterilefragments are different and the species
may be distinct.
Occurrence: Common (sterile leaves).
Specimens: CH-007, CH-016, CH-017,
CH-018, CH-036, CH-042, CH-048, CH-055.

Siberian specimen, secondary nerves are
more densely crowded than those of ours.
It would be worthy to note that
Osmunda-type ferns became abruptly
common or abundant in occurrence inthe late early Cretaceous floral sequencein Siberia.
We have not encountered such Osmunda-type ferns as mentioned above in
the Oguchi and the Akaiwa Floras, thelower and the middle parts of the early
Cretaceous floral sequence in the Tetori
Basin.
Specimen: CH-006 (one specimen only).

Filicales
Gleicheniaceae

Genus Osmunda LINNE, 1753
? Osmunda sp.
PI. 1, fig. 3; Text-figs. 2a, b

Description: PI. 1, fig. 3 shows a small
pinna fragment bearing pinnules which
are oval in form, entire, with constricted
and decurrent base, and with bluntly
pointed apex. Pinnules are 0.45-0.55 cm
long and 2-2.5 mm maximum wide andattached nearly perpendicularly to pinna
axis. Nerves are distinct, midnerve ispersisting to the tip, sending off 5-6
pairs of secondaries forking dichotomously once except an apical pair.
Remarks: JUdging from the outlineof pinnules and their constricted base,it would be sure that this specimen belongs to the genus Osmund a, though its
fertile part has not been found.
In outline of pinnules and venation,
this specimen resembles OS11lunda sp. 2
described by SAMYLINA (1976, p. 21,
pI. 1, figs. 7, 8; text-fig. 1) from the
middle member of Omsukchan Formation in the Kolyma Basin, though in the

Genus Gleichenites GOEPPERT, 1836: 172
Gleichenites nipponensis OISHI
Text·figs. 3a, b
Gleichenites nipponensis OISHI; 1940 (pars), p.
202, pI. 3, figs. 3, 3a (non fig. 2)(Mochiana, Upper Jurassic Kuzuryu Group) ;1941, p. 169, pI. 37, figs. 1, 2, 2a, Lo·tzukou Series, NE·China); KIMURA, 1958b,
p. 13, pI. 1, figs. 2, 3, pI. 3, fig. 4; pI. 4,
fig. 5; text·figs. 1, 2 (Mochiana).
Cladophlebis exiliformis (GEYLER) OISHI; 1940
(pars), p. 261, pI. 13, fig. 2; pI. 15, figs. 2,
2a (Kuwashima, Oguchi Formation); 1941,
p. 170, pI. 36, fig. 4 (Lo·tzu·kou Series);
KIMURA, 1959b (pars), p. 21, pI. 1, fig. 5(Hakogase, Oguchi Formation).
Cladophlebis sp. a; OISHI, 1941, p. 171, pI. 36,
figs. I, la (non figs. 2, 2a) (Lo·tzu.kou
Series).

Remarks: Many sterile and fertile
pinna fragments were obtained. The
fertile ones agree well with those from
Mochiana and Lo-tzu-kou as Gleichenites
nipponensis, and the sterile ones also
agree with those from Kuwashima of the698. Late early Cretaceous plants
Oguchi Formation and Lo-tzu-kou. The
sterile leaves now referable to this species have so far been regarded as Cladophlebis exiliformis (pars) and C. sp. a(pars) by OISHI and KIMURA.
Recently KIMURA & SEKIDO collecteda good number of both sterile and fertile
leaves in organic connection, from Kuwashima and Mekkodani, of the Oguchi
Formation. These new material will be
described in detail in their monographof the Oguchi Flora (KIMURA & SEKIDO,
YlS) in the near future.
KIMURA & KANSHA (1978) described
Gleichenites yuasensis sp. nov. from theUpper Neocomian Arida Formation, Wakayama Prefecture, in the Outer Zoneof Japan. They included OISHI's Gleichenites nipponensis from Kaisekiyama of
the Ryoseki Group (OISHI, 1940, pI. 3, fig.
2) and NATHORST'S Pecopteris geyleriana(NAT HORST, 1890, pars) in this new species. They pointed out differences in theform of the sterile pinnules.
Occurrence: Common.
SPecimens: CH-OOl, CH-002, CH-OlO,
CH-Oll, CH-012, CH-022, CH-026, CH-027,
CH-041, CH-045, CH-046, CH-049, CH-050,
CH-052, CH-054, CH-061, CH-100.
Dicksoniaceae
Genus Coniopteris BRONGNIART, 1849: 26

Coniopteris cfr. arctica SAMYLINA
PI. 1, figs. 4, 5; Text-figs. 4a-cComparable specimens:
Coniopteris arctica (PRYNADA) SAMYLIKA;
1963, p. 70, pI. 2, figs. 2-7; pI. 3, fig. 5a(Lower Cretaceous of the Aldan and theAmga); 1964, p. 56, pl. 5, figs. 11-13 (BuorKemyuss Formation, Zyrianka Coal-Basin) ;1976, p. 25, pI. 7, fig. 2a; pI. 41, fig. 13a(Middle member of Omsukchan Formation,

7

Kolyma Basin).
Coniopteris efr. arctica (HEER); VASSll.EVSKAJA & PAVLOV, 1963, pI. 3, fig. 1 (Kyusyur Formation, Lena Basin).
Dicksonia arctica (PRYNADA) KRASSILOV; 1973,
p. 32 (Tschenitschuko Formation, Bureja
Basin).

Description: Several pinna fragments
were obtained. Owing to the incompleteness of our material, the shape of thewhole leaf is not known. Pinnules examined by us are all sterile, varied in form andsize, set closely or somewhat remotelyon the slender pinna axis which has amedian longitudinal furrow on its uppersurface (Text-fig. 4a) as commonly seenin those of other Dicksoniaceous ferns.
Pinnules are typically oval or rhomboidal
in form, decurrent at base, their laminae
are deeply divided into 5-6 pairs of lobes,
but the sinuses do not reach themidnerve. Lobes are entire, generally
directed forwards and with bluntly
pointed or rounded apex. Nerves aredelicate and typical Sphenopteris-type as
if sympodial branching in appearance;each lobe receives one set of sympodiallybranched secondaries are shown in Textfigs. 4a, b.
RemarllS: Among more than 30 Dicksoniaceous species known at present fromthe Upper Jurassic to the Lower Cretaceous strata in Siberia, the present sterileleaves most closely resemble in the formof pinnules and the venation those ofConiopteris arctica from the Lower Cretaceous of Kolyma Basin and its adjacentarea and of C. cfr. arctica from theLower Cretaceous of Lena Coal-Basin.
Dicksonia arctica from the Lower Cretaceous of Bureja Basin would also be
similar in form to the present leaves,though KRASSILOV has not illustrated
this species.
However, we hesitate to refer ourTatsuaki KIMURA and Jun}i HORIUCHI

8

1b

~X4
) la

5a

5b
X4

2b

X4·~

4c

4b
4a

3b

3a

2a

698. Late early Cretaceous plants

9

7c

7a

7b

", ,

L
2.

3_
4.
5.

6.
7.

Text-figs_ 1-7 (All enlarged twice, unless otherwise stated)_
Cfr_ Osmundopsis efimoviae SAMYLlNA; 1a: sterfie pinn~ fragment (CH-016). 1b: enlarged
partly from la to show the venation.
? Osmunda sp.; 2a: sterile pinna fragment (CH-006). 2b: enlarged from 2a to show theoutline of a pinnule and its venation.
Gleichenites nipponensis OISI-II; 3a: sterile pinna fragment (CH-026) _ 3b: fertile pinna
fragment in close association -with 3a in occurrence.
Coniopteris cfr. arctica (PRYNADA) SAMYLlNA; showing varied forms of pinnules, partly
wi th their venation (4a: CH -053, 4b: CH -057, 4c: CH -023) .
Birisia onychioides (VASSILEVSKAJA & KARA-MuRSA) SAMYLlNA;
5a: long and narrow pinnules on the posterior part of a frond (CH-014).
5b: enlarged from 5a to show the venation. .
Asplenium disksonianum HEER; a part of penuitimate pinna, showing the outline of pinnules (CH -028).
. ..
Podozamites eichwaldii SCIII:vJPER; showing the· leaf-form and the venation (7a: CH-015,
7b: CH-OOB, 7c: CH-059).
.,~,

sterile leaves fully to C. arctica and treat
them here as C. dr. arctica, because
in our collection fertile leaves have notbeen found. This is the first occurrenceof a fern like Coniopteris arctica in the
Inner Zone of Japan.
Occurrence: Common.
Specimens: CH-003, CR-009, CH-023,

CH-029, CH-034, CH-037, CH-039, CH-044,
CH-047, CH-053, CH-056, CH-057.
Genus Birisia SAMYLINA, 1972: 95
Birisia onychioides (V ASSILEVSKAJA& KARA-MuRSA) SAMYLINA

10

Tatsuaki KIMURA and Junji HORIUCHI
PI. 1, fig. 6; Text-figs. 5a, b

Dicksonia gracilis HEER; 1878, p. 13, pI, 3, figs.
8-11 (Lower Cretaceous of Lena Basin).
Cladophlebis shinshuensis T ATEIW A; 1929,
plate, fig. 24 (Jinju Formation, NagdongGroup, Korea); OISHI, 1940, p. 285, pI. 20,
figs. 5, 6; pI. 21, figs. 5, 5a, 6, 7 (Ditto);
KIMURA, 1958a, p. 116, pI. 25, figs. 1, 2;
text-fig. 1 (Middle Formation of TamodaniGroup).
Coniopteris onychioides V ASSILEVSKAjA & KARA-MuRsA; KRYSHTOFOVICH, 1957, p. 231,
fig. 201 (introducing V ASSILEVSKAJA'S specimen); VAKHRAMEEV, 1958, p. 77, pI. 3,
fig. 6; pI. 4, figs. 1-3; pI. 5, figs. 1, 2; pI.
6, figs. 3, 4 (Lower Cretaceous of Lena
Basin); VASSILEV::'KAJA & PAVLOV, 1963,
pI. 11, fig. 3; pI. 19, figs. 5, 6; pI. 31, figs.
6-8, 9a (Ditto) ; SAMYLINA, 1964 (pars), p.
60, pI. 8, fig. 2; pI. 9, figs. 1, 3, 5 (Lower
Cretaceous of Zyrianka Coal-Basin) ; ABRAMOVA, 1970, p. 38, pI. 1, figs. 3-5 (Lower
Cretaceous of Lena Basin).
Birisia onychioides (VASSILEVSKAjA & KARAMURsA) SA:-n'LINA; 1972, p. 100 (nomenc1ature); KnwRA, 1975, p. 71, pI. 5, figs.
6-9; pI. 6, figs. 1-4; text-figs. 4-2a-d(Middle Formation of Tamodani Group);
KIMCRA & SEKIDO, 1976, p. 352 (Ditto);
SAMYLI:'-JA, 1976, p. 24, pI. 3, figs. 1-3; pI.
4, fig. 1 (Lower Cretaceous of Omsukchan).

Remarks: The above list shows how
common is this species in the early
Cretaceous floras in Eastern Siberia andits adjacent areas. This species is easily
distinguishable from other Dicksoniaceous ferns by its Cladophlebidium-typesterile pinnules with many pairs of lobes
strongly directed forwards. Many sterile
leaf-fragments were found in our collection and one of them is illustrated here
(PI. 1, fig. 6). Judging from the characteristic pinnules as shown in Text-figs.
5a and 5b, the present leaves are undoubtedly referable to this species, although
the fertile leaves have not been found.
Recently many good specimens refera-

ble to this species were collected from
the Mekkodani of the Oguchi Formation_
They will be described in detail by KIMURA & SEKIDO in the near future.
Accordingly, this species is one of thecharacteristic elements in the early
Cretaceous floras in the Inner Zone ofJapan.
Occurrence: Common.
SPecimens: CH-004, CH-005, CH-014,
CH-033, CH-043, CH-063, CH-064.

Aspleniaceae
Genus Asplenium LINNE, 1753
Asplenium dicksonianum HEER
PI. 1, fig. 7; Text-fig. 6

Asplenium dicksonianum HEER; 1874, p. 31, pI.
1, figs. 1-5 (Lower Cretaceous? of Greenland); KRYSHTOFOVICH & BAIKOVSKAJA,
1960, p. 11, pI. 1, figs. 1-6; pI. 2, figs. 1-4;
text-figs. 2-4 (Upper Cretaceous of Sakhalin); V ASSILEVSKAjA & PAVLOV, 1963,
pI. 33, figs. 1-3 (Ukin Formation, Lena
Basin) ; SAMYLINA, 1964, p. 63, pI. 11, figs.
1-3 (Siliap and Buor-Kemyuss Formations,
Zyrianka Coal-Basin); LEBEDEv, 1974, p_
40, pI. 6, fig. 4 (Albian Formation of Priokhotie); SAMYLINA, 1976, p. 34, pI. 14,
figs. 3-5; pI. 17, fig. 6 (Omsukchan andToptan Formations, Kolyma Basin).
For further references, see KRYSHTOFOVICH & BAIKOVSKAjA, 1960, p. 11.

Description: PI. 1, fig. 7 shows an incompletely preserved delicate fern frond
closely referable to this species, especially to the original specimens describedby HEER. Pinnules are long and narrow,linear, attached to the slender pinna
axis at acute angle and shallowly divided
into four pairs of lobes, typically 8.5 mm
long and 1 mm wide. Lobes are directed
forwards and with acutely pointed apex_(The fructification has not been found).

698.

Late early Cretaceous plants

Text-fig. 6 shows the outline of pinnules. The figure suggests that thearrangement of the pinnule is anadromic
but we can not be certain that this iscorrect.
Remarlls: In this species, pinnules
fairly vary in form as shown in previous illustrations. Although the present
specimens are incomplete, their pinnules
agree with those of original specimensof this species.
This species has been known from theplant beds after the Aptian age mainlyin Siberia and Greenland. The occurrence of this species is the first recordin Japan, although KIMURA & SEKIDO(1976) described two fern fragments
under the name of Asplenium cfr. dicksonianu11l from the Osugidani of the
Akaiwa Formation.
Occurrence: Common (but fragmentarily).
Specimens: CH-021, CH-028.

Unclassified fern
Genus Onychiopsis YOKOYAMA, 1889: 26

Onychiopsis elongata (GEYLER)YOKOYAMA
Onychiopsis elongata (GEYLER) YOKOYAMA;
1889, p. 27, pi. 2, figs. 1-3, 4a-c (Oguchi
Formation) .
For further references, see KI~wRA, 1975,
p. 77.

Remarks: This species occurs richly
in the underlying plant beds, but is rarein the Chinaboradani Formation and has
not been found in the Uppermost Formation of Tamodani Group.
This species was luxuriant in the early
Cretaceous age both in the Outer and theInner Zones of Japan, but has not beenfound in rocks of that age in Siberia

11(V AKHRAMEEV, 1971, p. 81).

Occurrence: Rare.
SPecimens: CH-019, CH-030, CH-031,
CH-032, CH-060, CH-158 (all minor fragments).
Unclassified conifer
Genus Podozamites BRAUN, 1843

Podozamites eichwaldii SCHIMPER
Text-figs. 7a-c
Podozamites lanceolatus eichwaldi HEER; 1876,
p. 109, pi. 23, fig. 4; pi. 26, figs. 2, 3, 9;
pi. 27, fig. 1 (Jurasso·Cretaceous of Bureja
Basin) .
Podozamites eichwaldii SCIIIMPER; V ASSILEVSKAJA & PAVLOV, 1963, pi. 16, fig. 5; pi. 27,
fig. 4; pi. 28, fig. 3; pi. 30, fig. la (Bulun
and Ogoner-Yuryakh Formations, Lena
Basin) ; SAMYLlNA, 1967, p. 151, pi. 8, fig.
9b; pi. 12, figs. 11-13 (Ozhoghina and BuorKemyuss Formations, Zyrianka Coal-Basin) ;LEBEDEv, 1965, p. 123, pi. 34, fig. 2 (Upper
Jurassic of the Zeia); 1974, p. 95, pi. 27,
fig. 1 (Albian Formation of Priokhotie).
Podozamites ex gr. eichwaldii SCHIMPER;SAMYLlNA, 1976, p. 61, pi. 33, figs. 1-3(Omsukchan Formation, Kolyma Basin).
Podozamites sp. cfr. P. eichwaldi SCHIMPER;
KIMURA, 1975, p. 84, pi. 8, fig. 10 (Uppermost Formation of Tamodani Group).
For further references, see SAMYLlNA, 1967,
p. 151.

Description: Several fragments ofPodozamites shoots bearing spirally disposed leaves. Leaves are generally smallsized, variable in form, elongate-oval(Text-fig. 7a) to oval (Text-fig. 7b), gradually narrowing towards the roundedor obtusely pointed apex and abruptly
narrowing to pass to short petiole (Textfig. 7c). Nerves are numerous, simple,
parallel to each other, converging at
apex, 36 in number in a leaf shown in
Text-fig. 7b.

12

Tatsuaki KIMURA and Junji HORIUCHI

Remarks: The present specimens agree
macroscopically with Podozamites eichwaldii which is widely known in theUpper Jurassic to the Lower Cretaceous
plant beds in Eastern Siberia.
Podozamites eichwaldii differs in leafform from such comprehensively defined
species as P. ex gr. lanceolatus widely
known in the Mesozoic plant beds in theworld. In P. ex gr. lanceolatus, as shownin its specific name, leaves are generally
lanceolate in form, but in this species
they are not lanceolate but generally
elongate-oval or oval.
Externally most nearly allied one tothis species is Podozamites reinii known
not only from the Lower Cretaceous in
the Inner Zone of Japan, but also fromthe Lower Cretaceous in Korea andEastern Siberia. But Podozamites eichwaldii differs from P. reinii in that in
P. reinii leaf bases are commonly ;'otund
while in P. eichwaldii they are unexceptionally attenuate. Moreover, leaf-formof P. eichwaldii, although it is .fairly
varied, is outside the range, of variationof P. reinii as shown by KIMURA & SEKIDO (1967, p. 418).
We now identify Podozamites sp. efr.
P. eichwaldii previously described by
KIMURA (1975, p. 84, pl. 8, fig. 10) fromthe Tamodani as P. eichwaldii. 'Occurrence: Common.
SPecimens: CH-008, CH-015, CH-051,
CH-059, CH-062.

Coniferae sp. (cone?)
PI. 1, fig. 8"

Pl. 1, fig. 8 shows a problematic organ
which ,looks like a catkin-like cone probably belonging to som~ con,ifer, morethan 6 em long and 1.5 em across measured on impression. This, organ isconsisting of numerous and irregularly

disposed circular or oval cone-seale-like
imprints, 2-2.5 mm in diameter.
Full description and discussion of thisorgan must await the discovery of better
specimens.
SPecimen: CH-038 (one slab only).
References
ABRANIOVA, L. N. (1970): Early Cretaceous
flora from Zygansk and the adjacent areasof the Lena Basin. Sci. Rep. Inst. Arct.
, Ceol., Min. Ceol. USSR, Palaeont. & Biostratigr., vol. 29, p. 36-57, pis. 1-10 (inRussian).
HARRIS, T. M. (1931a): Rhaetic floras. Bioi.
Rev., vol. 4, no. 2, p. 133-162.
- - (1931b): The fossil flora of Scoresby
Sound East Greenland. Med; om Cr<jJnland,
Bd. 85, nr. 2, p. 1-104, pis. 1-17.
- - (1961): The Yorkshire Jurassic flora I.
Thallophyta:Pteridophyta. ix +212 pp. Brit.
Mus. (Nat. Hist.).
HEER,(1874): Die Kreide·Flora der arctischen Zone. K. svensk. Vet .. Akad. Handl., Bd. 12, no. 6, p. 1-140, pis. 1-38 (Florafoss. Arct., 3-2)., .
- - (1876): Beitrage zur Jura·Flora Ostsibirienll, und des Amurlandes. Mbn. Acad.
Imp. Sci., St.-Petersb., ser. 7, vol. 22, no.
12,"p. 1-122, pis. 1-31 (Flora foss. Arct.,4-2).
- - (1878): Beiti'age zui' fossil en Flora Sibiriens. Ibid., vol. 25, no. 6, p. 1-58, pis.
1-15 (Flora foss. Arct., 5-2).
KI~mRA, T. (1958a): Mesozoic plants fromthe Tetori series, Central Honshu, Japan(Part 1). Trans. Proc. Palaeont. Soc. Japan, N. S., no. 29, p. 166-168, pI. 25.
(1958b): On the Tetori flora (Part 1).
Mesozoic plants, from the Kuzuryu subgroup, Tetori group, Japan: Bull. Sen.
High Sch.; Tokyo Univ. Educ., ll-2, p. 1'47, pis. 1-4.
- - (1975) : Middle·late early Cretaceous,plants newly found from the upper courseof the Kuzuryu river area, Fukui Prefec..ture, Japan. Trans, Proc. Palaeont., Soc.
J(lpan, N.,S., no.,98, p. 55-93, pis. 5-:8.. ,

0:

698.

Late early Cretaceous plants- - (1976): Mesozoic plants from the Yatsushiro formation (Albian), Kumamoto Prefecture, Kyushu, Southwest Japan. Bull.
Natn. Sci. Mus., ser. C (Geol. & Palaeont.),
vol. 2, no. 4, p. 179-208, pis. 1-6.
- - & HIRATA, M. (1975): Early Cretaceous
plants from Kochi Prefecture, Southwest
Japan. Mem. Natn. Sci. Mus., no. 8, p.
67-90, pis. 10-13.
- - & KANSHA, Y. (1978): Early Cretaceous
plants from the Yuasa district and theAridagawa valley, Wakayama Prefecture,in the Outer Zone of Japan. Bull. Natn.
Sci. Mus., ser. C. (Geol. & Palaeont.),
vol. 4, no. 3, p. 99-116, pis. 1-4.
- - & SEKlDO, S. (1967): Some Mesozoic
plants from the Itoshiro subgroup, theTetori group, Central Honshu, Japan.
Prof. H. Shibata Mem. Vol., Tokyo Univ.
Educ., p. 416-419, pis. 1-3.
- - & . - - (1976): Mesozoic plants fromthe Akaiwa formation (Upper Neocomian),
the Itoshiro group, Central Honshu, Japan.
Trans. Proc. Palaeont. Soc. Japan, N. S.,
no. 103, p. 343-378, pis. 36-39.
- - & - - (1978 MS): The earliest Creta·
ceous Oguchi flora, in the I nner Zone ofJapan.
KRASSILOV, V. A. (1973): Material on thestratigraphy and tafofloras of the coalbearing strata of Bureja Basin. In Fossil
floras and phytostratigraphy of the Far
East. Far East Geol. Inst., Far East Sci.
Center, Acad. Sci. USSR, Vladivostok, p.
28-51, pis. 13-17 (in Russian).
KRYSHTOFOVICH, A. N. (1957): Palaeobotany(Text-book). 650 pp. Leningrad.
- - & BAIKOVSKAjA, T. N. (1960): Creta·
ceous flora of Sakhalin. KOMAROV Bot.
Inst., Acad. Sci. USSR, Moscow-Lenin·
grad, p. 1-122, pis. 1-21 (in Russian).
LEBEDEY, E. L. (1965): Late Jurassic flora
from Zeia and boundary between Jurassic
and Cretaceous. Geol. Inst., Acad. Sci.
USSR, Trans., vol. 125, p. 1-142, pis, 136 (in Russian).
- - (1974): Albian flora and Lower Cretaceous stratigraphy of West Priokhotie.
Ibid., vol. 254, p. 1-147, incl. pis. 1-31
(in Russian).

13

MAEDA, S. (1957a): Stratigraphy and geological structure of the Tetori group along
the Uchinami and Itoshiro Rivers, Fukui
Prefecture. Jounz. Geol. Soc. Japan, vol.
63, no. 741, p. 357-365 (in Japanese).
- - (1957b): The Tetori group in the Oyama
area, Itoshiro village, Fukui Prefecture.
Ibid., vol. 63, no. 747, p. 664-668 (inJapanese).
- - (1958): Stratigraphy and geologicalstructure of the Tetori group in the Hakusan district (Part 1 Stratigraphy). Ibid.,
vol. 64, no. 758, p. 583-593 (in Japanese).
NATHORST, A. G. (1890):
Beitrage zur
mesozoischen Flora Japans. Denksch.
Math.-Nat. Cl. Kaiser. Akad. Wiss., Bd.
57, p. 41-60, pis. 1-6.
OISHI, S. (1940): The Mesozoic floras ofJapan. Journ. Fac. Sci., Hokkaido Imp.
Univ., ser. 4, vol. 5, nos. 2-4, p. 123-480,
pis. 1-48.
- - (1941): Notes on some Mesozoic plantsfrom Lo-tzu·kou, Provo Chientao, Manchoukuo. Ibid., vol. 6, no. 2, p. 167-176, pis.
36-38.
SAMYLINA, V. A. (1963): Mesozoic flora of
the lower course of the Aldan River.
Komarov Bot. Inst., Acad. Sci. USSR,
ser. 8 (Palaeobot.), vol. 4, p. 59-138, pis.
1-37 (in Russian).
- - (1964): Mesozoic flora of the area tothe west of the Kolyma River (Zyrianka
Coal-Basin), Pt. 1. Ibid., vol. 5, p. 41-78,
pis. 1-18 (in Russian).
- - (1967): Ditto, Pt. 2. Ginkgoales, Coniferales, General chapters. Ibid., vol. 6,
p. 133-375, pis. 1-14 (in Russian).
- - (1972): Birisia-New genus of Cretaceous ferns of Siberia. Journ. Bot., Acad.
Sci. USSR, vol. 57 (1972-1), p. 94-101,
incl. pis. 1-2 (in Russian).
- - (1976): The Cretaceous flora of Omsukchan (Magadan District). Komarov Bot.
Inst., Acad. Sci. USSR, Leningrad, p. 1206, incl. pis. 1-48 (in Russian).
TATEm'A, 1. (1929): Geological atlas of
Chosen (Korea), no. 10, Keishu-Eisen·Taikyu and Wakwan Sheets, 1/50000. Geol.
Surv. Chosen (Korea).
VAKI-IRAMEEV, V. A. (1958): Stratigraphy and14

Tatsuaki KIMURA and Junji HORIUCHI

fossil plants from the Jurassic and Cretaceous deposits of the Vi lui Basin andVerchojansk foredeep.
Reg. Stratigr.
USSR, Geol. Inst., Acad. Sci. USSR, vol.
3, p. 1-128, pis. 1-32 (in Russian).
- - (1971): Development of the early Cretaceous flora in Siberia. Geophyt., vol. 1,
no. 1, p. 75-83.
VASSILEVSKAJA, N.D. & PAVLOV, V.V.
(1963): Stratigraphy and flora from Cre-taceous beds of Lena-Olenek region of Lena
Coal-Basin. n Problems of oil and gas
content beds in Arctica. Bull. Inst. Arct.
Geol., Min. Geol. & Protect. Undergr. Res.,
USSR, vol. 128, p. 1-96, pis. 1-49 (in Russian).
YOKOYAMA, M. (1889): Jurassic plants from
Kaga, Hida and Echizen. Tokyo. Coli.
Sci., Imp. Univ. Tokyo, vol. 3, pt. 1, p. 166, pis. 1-14.

Akaiwa $!Ef,
Arida ~83,
Chinaboradani 9;DmilJiJ~,
Hakogase lii?"iiJt,
Itoshirogawa:fifi«SJII,
Jinju l1f~1'1,
Kaisekiyama fl':fill.!,
Kitadani ~t~,Kuwashima ~~,Kuzuryu iLID'lit!;,Lo-tzu-kou BiT-M,
Mochiana fif/\:,Nagdong
JR,
Nobudani/ 7~,
Oguchi ~I::J,
Omichidani :;k~~,Osugidani :;kf~1:t,
Oyama :;kll.!,
Takinamigawa ill!iltiJII,
Tamodani 83D€~ (83fJJ:~),
Tetori ~1&,
Uchinamigawa triltiJl1m

S*I*Hll'm:lf!Jjt~iitrjlJjs1lli~c1~WHl1i4to{t:fi: :fifi«s~~Q)Iill:l:(:jt(flll;t~)j}(!Ef oliP!Ef· J{;fiQ)
BJ~tJ'~t.r.lJ, m;;:t:lt!!-CI;t~t~~c1fl;~~:h-r:I.'7.:>0 ~t~~11**::t ~ 7;/l:ffllc~;t~:h-r:
I.'7.:>$!Ef~a-~il"t:'1Bll.', J:ffllS1lli*Q):;k)fi~I\~H:..t lJ 'f~il"t:'1Bln:h7.:>o ~t~~;j§~~I;t83
D€~J:Vlt:, triltiJII:to.t O%1fjI(SJIIJ:Vlt::It!!:JIiXf:.73-;fjJL, -t:Q)M4to~11[l&~M!fo/.J~c 1fI;~ ~:ht.:.

(KIMURA, 1975)0 4'@], :Ofi«SJIIJ:Vlt::It!!:JIiXQ)~t~~;j§~~-C.:l;7.:>9;omlilJiJ~@tJ>~, '0~Q)fl1i¥&1!f-t 7.:> 0 Cfr. Osmundopsis efimoviae,? Osmunda sp.,
Gleichenites nipponensis, Coniopteris efr. arctica, Birisia onychioides, Asplenium
dicksonilLnum, Onychiopsis elongata, Podozamites eichwaldii, Coniferae sp.
83D€~M4o/.J~Q)m.ffltl;tJ;l,J:a-1JD;t22m!c t.r. -? t.:.o 83&~M4o/.J~t:.ml-t 7.:> ~;jSH;t*t':z. L I. ,t.:.
ilb~ <a-;m"'q;: c 11-C~t.r.I.'tJ~, S*P:i*t:.:to\.,-r:, 1BlTfl1i4o/.Ja-~"£ t.r.Hi~Q)M4tJ~-C.:l;IJ, "£ t.:. -/ ?" tJ~(f~-C, -I:!;/ 71 t:. W,t.:. -/ ?"a-I;t r. ilb, Coniopteris efr. arctica, Asplenium
dickson/anum, Arctopteris t.r. c·Q)~jlJjml.Q) -/ ?"a-~tro[lD€~M¥.o~I;t, -t:Q)m.Jil!:tJ>~ VAKHRAMEEV Q)I.'? -/"'~ 7M4tJ:It!!W.gQ)ji'ij~jtJlQ)M4o/.J~t:..t lJ Jl[*l-C.:l; lJ, ji'ijl!ifJtJjQ) S*?1-*Q)I.,nt1>7.:> Wealden ml.Q)llEi4tJ~Q)m.Jil!:cl;t~L <.~7.:>0*H.~o.P:i~~
4o/.Jm!a-~~7J1j L t.:.Q)-C;: ;: t:.~tI:,

Explanation of Plate 1
Figs. 1, 2. Cfr. Osumundopsis efimoviae SA:\,IYLlXA (Fig. 1; CH-0l6, Fig. 2; CH-048), x 2.
Fig. 3. ? Osmund a sp. (CH-006), x2.
Figs. 4, 5. Coniopteris efr. arctica (PRYNADA) SA:\IYLlNA (Fig. 4; CH-053, Fig. 5; CH-056),
Fig. 6.
Fig. 7.
Fig. 8.

x2.
Birisia onychioides (VASSILEVSKAJA & KARA-MuRSA) SA:\IYLlNA (CH-063), x 2.
Asplenium dicksonianum HEER (CH-028), x 2.
Coniferae sp. (cone?) (CH-038), xl.

KIMURA and HORIUCHI:

Late ea?'ly Cretaceous plants

Plate 1

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 113, pp. 15-29, pIs. 2, 3, April 30, 1979

699. OCCURRENCE OF CRETACEOUS SHALLOW-SEA BIVALVESFROM THE NORTHERN BORDER OF SHIMANTO TERRAIN,KII PENINSULA, SOUTHWEST JAPAN*
KEIJI NAKAZAWA, FUJIO KUMON and KATSUMI KIMURA
Department of Geology and Mineralogy, Kyoto University, Kyoto, 606

Abstract. Bivalve fossils collected from the northern border of the Shimanto
Terrain are characterised by shallow marine species, such as Spondylus aff. deco.
ratus, Plicatula aff. hanaii, Amphidonte d. subhaliotoidea, Rastellum? sp., Ostrea sp.
and others, the age of which is considered to be early Cretaceous. The fossilbearing sandstones also show a shallow shelf environment, while the surrounding
sandstones indicate turbidity current origin under bathyal environment. The presence of shallow-sea sediments among the turbidite sequence is explained by sealevel change and not by submarine slide of the shallow-sea sediments.

HASHIMOTO (1968, 1970) reported the occurrence of several late Cretaceous bivalves belonging to Acila, Mesosaccella,Nanonavis, Inoceramus, and Periploma,
and NOHDA (1966, MS) collected Inoceramus concentricus costatus NAGAO and
MATSUMOTO of early Gyliakian (-~Ceno­
man ian) age. Very recently NAKAJO(oral comm.) distinguished early Cretaceous and latest Jurassic-earliest Cretaceous radiolarian assemblages in chert.
All of these fossils have not been described yet, however. In the present
article the authors will describe newly
discovered bivalves of very shallow-sea
origin and discuss the sedimentologicalsignificance.
The authors take this opportunity to
express their cordial thanks to the members of the Kishu Shimanto ResearchGroup for their help in sampling fossils
and to Dr. N. YAMAGIWA of Osaka University of Education for his identification of corals. Dr. I. HAY AMI of the
University of Tokyo and Dr. A. MATSU-

Introduction and acknowledgments
The Shimanto Terrain represents oneof the major geosynclinal belts in Japan,
extending along the Pacific coast ofCentral and West Japan and ranging
from late Jurassic to earliest Miocene inage. In Kii Peninsula it is divided into
two belts, namely, the northern Hidakagawa belt occupied by the late Mesozoic
Hidakagawa Group and the southern
Muro belt made of the Paleogene toearliest Miocene Muro Group. The
former consists mainly of flysch-likealternations and shales intercalated withcherts, conglomerates, submarine basic
rocks, and acid tuffs. Very few fossils
have been discovered so far.
Only
Inoceramus d. amakusensis NAGAO and
MATSUMOTO, I. cf. cycloides WEGNER,
and I. d. ezoensis YOKOYAMA have been
described, which indicate the late Urakawan (~Santonian) age (MOROZUMI, 1970).
* Received Oct. 6, 1978; read Jan. 20, 1978
at the Annual Meeting of 1978 at Kyoto.

15

Keiji NAKAZAWA, Fujio KUMON and Katsumi KIMURA

16

LEG END
Alluvium
Terrace Deposit
Futakawa Formation( late Cretaceous
Undivided Mesozoic & Palaeozoicv"vv Acid Tuff

y

Chert

Yukawa Formation

§

Shale

t:-d Shale with ss. & alternation[I]J

Sandstone with alt. & sh.

U Sandstone
1····1 Muddy conglomerate

Normal Bedding.....Y Reversed Bedding/ ' Order unknown

ij Fault)\

Fossil Locality..---'>

Paleocurrent

Figure 1.

Index map (lower right) and geological map around fossil locality.
A: Shimizu, B: Nonoshiri, C: Doganaro

699. Cretaceous Bivalves from Shimanto Terrain
KUMA of Kyushu University gave thesenior author facilities in examining theallied species kept at their universities.
Thanks are due to these gentlemen.
Geological note and age-assignment

The Hidakagawa belt is bordered with
the Chichibu belt on the north by the
Butsuzo Tectonic Line. The Hidakagawa
Group constituting the former belt in thecentral Kii Peninsula is divided from
north to south into four formations,
namely, the Yukawa, the Miyama, theRyujin, and the Nyunokawa Formations(NAKAZAWA, 1973; KISHU SHIMANTORESEARCH GROUP, 1975). The Yukawa
Formation is in fault contact with theMiyama Formation which overlies conformably the Ryujin Formation. It consists mainly of bedded sandstones, fiyschlike alternations, and shales with a small
amount of acid tuff, lenticular chert, andconglomerate in the surveyed area. The
beds have a general strike of E- W direction dipping to north or south at steep
angle (45° to 90°). North-dipping strata
show a normal order while south-dipping
ones are reversed, and therefore, thestructure is as a whole simple, becoming
younger to the north, although several
strike- and oblique faults are observed(Fig. 1).
Table 1.
species17

Early Gyliakian Inoceramus concenticus
costatus was once collected by NOHDA
from shale in the northern part (Fig. 1,
loco 1).
The fossils under consideration arecontained in medium- to coarse-grainedsandstones in the middle part at about
3 km upper stream of the R. YUKAw A
from SHIMIZU (Fig. 1, loco 2). Fragmental
shells were also found in its eastern extension (Fig. 1, loco 3). These fossils are
identified as in Table 1.
It is interesting to note that most ofthese fossils show characteristics of avery shallow sea environment, having
thick, sessile shells which are frequently
burrowed by other organisms. Threebivalve species, Spondylus decoratus,
Amphidonte subhaliotoidea, and Plicatulahanaii, allied to the present materials
were all described from the Miyako
Group in Northeast Japan, the type ofthe Miyakoan (Aptian-Albian). The
subgenus Rastellum (Rastellum) ranges
from Middle Jurassic to Late Cretaceousand Rastellum (Arctostrea) is confined toLate Albian-Early Cenomanian in age(STENZEL, 1971). According to Dr. YAMAGIW A, associating corals belong toCalamophyllia and are most similar to
the Alpine C. schmidti (KOBY) of Neocomian age. Judging from these fossils
mentioned above, the fossil-bearing sand-

List of fossils and the occurrence of the allied species.
occurrence of allied species

Spondylus sp. aff. d.ecoratus ........ Lower Miyako Group (Aptian)Amphidonte sp. cf. subhaliotoidea ... . Miyako Group (Aptian-Albian), Inubo Formation(Aptian), Doganaro Formation (Aptian-Albian)Plicatula sp. aff. hanaii ............ Miyako Group (Aptian-Albian)Ostrea sp. indo
Rastellum? (s. I.) sp. indo
Astarte? sp. indo
Bivalvia, gen. et sp. nov. indo
Calamophyllia sp. indo .............. C. schmidti (KOBY), Neocomian, Alps

18

Keiji NAKAZAWA, Fujio KUMON and Katsumi KIMURA

stones are assigned to be early Cretaceous and consequently earlier than the
Inoceramus-bearing shales in this region.
This accords with the stratigraphic succession.
In addition to these fossils, an incomplete shell of Spiriferina-like brachiopod
has been collected from Loc. 3 in association with Cretaceous fossils. This may
be a secondarily derived fossil.

and shales as already stated. Muddy
conglomerate or pebbly siltstone, thinacid tuff, and lenticular chert are also
found. Sandstones are usually thickbedded and massive, but graded texture
and flute casts on the sole surface areoften observed, suggesting the turbidity
current origin of these sandstones. Bedded sandstones and sandy alternations
around fossil locality are, therefore, considered to have been deposited at proximal site of turbidite deposition. This is
supported by grain-size distribution ofsandstones as will be stated later. In
spite of such environment the fossil as-

Sedimentological consideration

The studied area is composed mostly
of bedded sandstones, sandy alternations,
N

f

o

10

20

30 m

,,--~

30m

""-'"-

7

~~
~~
~

,20

~

8

..... 55.sh.
.... "0
~."

~

"\

---

:::

~

~~.

"\ 2

10

3

I

~

'.

cgl.

10

..

~

.. '.

Is.
0
cgl.

11

4
~,.,.

12

Figure 2. Route map and columnar section near fossil locality. 1: strike and dip, nor.
mal, 2: reversed, 3: unknown, 4: fault, 5: fissility, 6: shale, 7: laminated shale with sandstone, 8: bedded sandstone with shaly parting, 9: sandstone, 10: muddy conglomerate or
pebbly siltstone, 11: fossil, 12: subangular pebble conglomerate.

699.
f, P
f, P
f, X

m, X
f

P

, G

f, P

m, G

Cretaceous Bivalves from Shimanto Terrain..

:.~::""':":":".:"":"":':":'"..:.::...::.::..:....:..:...

-,---,,-

-~

f, P

.~~~~

..

19

c-m, r~

m, P
50

f, P
40

30

20
f-m, 11
10

f, P

f, P
em

f, P

IT2J

m, X

sands tonesands tone, more . or 1ess
~ muddy
carbonaceousf, PI'~~:I

e, X

...
...

muddy sandstone, laminationstrongly bioturbatedworm-burrm·/--_ ..... "" ............... _. -_ ..... _....... -_._ ....... - ...

, ___ • • • • • 0 . . . . . . . . . . . . . .
~

_._._

. . . . . . . . . __ , _ . _•••••••••••---- _...................._ .. -.- ............................

~." bivalve-shell

Figure 3. Sketch showing sedimentary structures and fossil occurrence.
c: coarse-, m: medium-, f: fine·grained sandstone, P: parallel·laminated, X: cross-laminated, G : grated.

sembi age shows a very shallow habitat,and detailed survey was done aroundthe fossil locality, paying special attention to the sedimentological features(Figs. 2 and 3).
Fossil-bearing sandstone beds are 35 m
thick along the R. YUKA W A and in beds
10-60 em thick. It is traceable laterally
over 1 km, conformably overlying fissile
shales and is graded into bedded sandstones with shale parting. The latter isin turn covered by black laminated sandy
shales, black shales, and muddy conglomerates or pebbly siltstones. The conglomerates contain round to subangularpebbles of sandstone surrounded by sandy
mud matrix, presumably formed by submarine slumping.
The fossil-bearing sandstone beds areintercalated with lenticular conglomerates at two horizons; one contains
many limestone pebbles of round toirregular shape and the other shale andsandstone clasts. Trough- and wedgeshape cross lamination and parallel lamination are common throughout. Shells
are crowded in the uppermost part ofthe beds, sometimes making cross laminae(Fig. 3). Coarse-grained, fossil-bearing
portion contains angular fragments ofhighly carbonaceous black shale of various sizes. Worm-burrows are especiallyabundant in muddy part and muddy
laminae arranged parallel or oblique tothe bedding plane. These sedimentaryfeatures indicate a high energy condition of flow regime under shallow environment.
Composition of sandstones is essentiallynot different between fossil-bearing sandstones and the surrounding turbiditic
ones (Fig. 4), all plotted within a compositional area of Cretaceous sandstones
in other regions of the Hidakagawa belt

20

Keiji NAKAZAWA, Fujio KUMON and Katsumi KIMURA
Yukawa Formation.. Northern part• Fossil horizono S'outhern part50
oo • '"

o 0

...

Z'•

t·

....

...

...
30
Plo

~ K-fel~Figure 4.

Triangular diagram showing composition of sandstone •

",

90

... L

'"
A

99

Rock Fragmen ts

50

Feldspar

j

Ii

B

j

j

-.----.---.-r""T---r-r-,- ~

99

1

I "

-;

~

~I

J

j
I

J __ l_~:_

-2

-1

a

I

,f

!

2

!

I

3

,

I

!

I

4

5 t

Figure 5. Cumulative curves on log-probability scale graph.
A: turbiditic sandstones, B: sandstones of fossil horizon.

(KISHU SHIMANTO RESEARCH GROUP,1977),
and clearly distinguished from that of
the Paleogene Muro Group in less amountof quartz and larger amount of rockfragments. It also resembles that of theCretaceous Hinodani Formation (KUMON,
1976, MS) and the Hayama Formation(MIYAMOTO, 1976) in Shikoku. There isa tendency in this area that rock fragments increase from south to north (Fig.
4, right).

On the other hand, grain-size analysis
under microscope shows a different sedimentary mechanism between the two.
Cumulative curves of the fossil-bearing
sandstones plotted on log-probability
scale graph (Fig. 5) indicate that distribution curves consist of two major segments with a small transitional part,which represent suspension population
and well-sorted saltation population.
Such distribution pattern is somewhat

699. Cretaceous Bivalves from Shimanto Terrain
similar to that of ancient fluvial sandstones or channel sands of VISHER (1969),
although the latter usually lacks transitional part. Contrarily to this, the turbiditic sandstones consist of rather
poorly sorted three populations and the
distribution curves are not comparable
to any shape of recent sediments studied
by VISHER (1969). He included such typein the miscellaneous curve shapes andsuggested debris flow origin. According
to VISHER turbidity current sediments
consist of two populations only, namely,
ill-sorted saltation population and suspension population. However, similar
pattern to the present sandstones isfrequently found in the typical tubidite
sandstones of the Cretaceous rocks in
Shikoku (KUMON, unpublished data) andthe Miocene Kumano Group in Kii Peninsula (HISATOMI, unpublished data), especially in coarse-grained ones. It is probable that this pattern of grain-size
distribution represents another distribution shape of turbidity current sediments.
All of these sedimentological datastated above strongly suggest different
sedimentary environments between thefossil beds and the surrounding ones,
that is, a shallow shelf environment of
the former and bathyal one of the latter.
How, then, can be explained such a shallow sediment intercalation among theturbidite sequence? There is no disturbance even at the contact of the sandstone beds with the underlying shaly beds.
This favours a continuous sedimentationof the sandstones on the shales rather
than submarine sliding.
In this connection, it should be mentioned that in the Chichibu belt immediately north of this area, the late
Urakawan C . Santonian) Futakawa Formation directly overlies the so-called
Paleozoic beds with a remarkable clinounconformity, lacking the lower Cretaceous

21

and Jurassic rocks in between (HIRAYAMA and TANAKA, 1956 ; SAKA, 1968). This
fact means that the sea coast must havebeen situated close to the Butsuzo
Tectonic Line in the early Cretaceoustime. In other words the fossil locality
was very near the sea coast (Fig. 6B).
Direction of trough-type cross lamination
indicates the supply of the sedimentsfrom the north. Predominance of proximal turbidite facies of this area alsosuggests a relatively shallow environment in the geosynclinal sea. Consequently, it is possible that a shelf condition was locally generated due torelative sea-level change,
Overlying shaly beds with slump conglomerates may be a proof of rapid
deepening of the sea after the depositionof the fossil-bearing beds. A huge lenticular body of chert, about 30 m thickand more than 200 m long, is found in
the eastern extension of the slump conglomerate horizon. The very contact
with the surrounding rocks is difficult
to be examined owing to thick cover ofchert debris, but a small exposure of thelower surface of another chert lens iswavy and the underlying shale containing small blocks of sandstone is a little
disturbed. The chert mass may be an
exotic block derived presumably from the
Chichibu belt. It contains sphaerical
radiolarian remains, but unfortunately,
the preservation is too bad for age
determination.
Lastly, it is noticeable that shallow
marine faunas of similar age to thisarea are found near the northern borderof the Shimanto Terrain not only in thisarea but also in Shikoku, such as the
Miyakoan Doganaro fauna of Kochi
Prefecture (HAY AMI and KA w ASAWA,
1967) and the lower Cretaceous (Neocomian?) fauna of Nonoshiri, Tokushima
Prefecture (SHINOAKE, 1958) (see Fig. 1,

Keiji NAKAZAWA, Fujio KUMON and Katsumi KIMURA

22
index map).

Superfamily Pectinacea

Systematic description

RAFINESQUE, 1815

(by K. NAKAZAWA)

Family Spondylidae GRAY, 1826

Order Pterioida NEWELL, 1965

Genus Spondylu5 LINNE, 1758

A

~4[]18 sI 'oJ 2 lmi 6
IilllIIII 3 ~ 7
B

IIII111 :699. Cretaceous Bivalves from Shimanto Terrain
Spondylus (Spondylus) sp. aff. S.
decoratus NAGAO, 1934
Plate 2, Figures 1-6

Compare:1934. Spondylus decoratus NAGAO, p. 210, pI.
27, figs. 2, 5-7.
1934. Spondylus sp. aft. decoratus: NAGAO,
p. 211, pI. 27, fig. 8.
1965a. Spondylus decoratus: HAYAMI, p. 324,
pI. 47, figs. 4-9; pI. 52, fig. 1.
1975. Spondylus (Spondylus) decoratus: HAYA'~II, p. 84, pI. 3, figs. 11, 12.

Description :-Shell medium In size,
suboval, a little inaequilateral, inaequivalve, extended posteroventrally. Leftvalve moderately inflated, slightly prosocline, a little higher than long, hinge
length short, posterodorsal margin longer
than anterodorsal one; umbo pointed,
orthogyrate, a little salient above hinge
margin having apical angle of about 900 ;hinge consisting of two, stout, granularcardinal teeth intervened with two subcircular cardinal sockets which have anarrow resilifer pit in between, borderedby ridge-like projection on both sides;
cardinal area amphidetic. obtusely triangular; surface sculptured with numerous
radial ribs, primary ones six or seven in
number, more or less stronger than

23

secondaries, which amount 4-7 in each interspace between primaries, and in somecases provided with irregularly spaced
short spines. Right valve only a part ofventral margin being preserved, ornamented by concentric costae.
Remarks and comparison:-Most of thematerials are represented by left valve,
and the exact comparison with known
species is difficult.
Strength of primary ribs of left valve
is fairly variable; in many specimens not
so broader than secondaries and provided
with no spines, but some have relatively
wide primaries with short spines (PI. 1,
Fig. 4).
There are known four species belonging to Spondylus in the Mesozoic injapan, namely Aptian S. decoratus NAGAO, 1934 of the Miyako Group in northeast japan, Santonian S. pseudocalcaratus TASHIRO, 1976 and S. sp. (T ASHIRO, 1976) of the Himenoura Group in
Kyushu, and the Upper Cretaceous S.
amanoi HAY AMI, 1975 (=S. japonicus
AMANO and MARUI, 1958) in Central
japan. The present species is distinguished from S. amanoi in much smallersize, less numerous radial ribs in the left
valve, and weaker concentric sculpturein the right valve. S. pseudocalcaratus
differs from this species in more de-Figure 6. Generalized geological map and paleogeography
A. Geological map of Yuasa·Shimizu area.
1: Upper Cretaceous, 2: Lower Cretaceous, 3: Upper Paleozoic to Jurassic, 4: Upper Paleozoic and Triassic, 5: Hidakagawa Group (Cretaceous) of Shimanto Supergroup, 6: Sambagawa
metamorphic rocks, 7: Kurosegawa complex (Silurian and pre-Silurian), a: Yuasa, b: Kanaya, c: Shimizu (Modified from TANAKA, 1974).
B. Paleogeography and paleocurrent direction of Miyakoan·Early Urakawan stage.
1: paleocurrent direction of Miyakoan-Gyliakian,
2: paleocurrent direction of Early Urakawan.
(Data added to those of TANAKA, 1974)
C. Paleogeography and paleocurrent direction of Late Urakawan stage.
B. T. L. : Butsuzo Tectonic Line.
(Paleocurrent data after TANAKA, 1974)

24

Keiji NAKAZAWA, Fujio KUMON and Katsumi KIMURA

veloped primary ribs in the less convex
left valve and stronger concentric ornaments in the right .. In general outline
and ornamentation, it is most allied to
S. decoratus which has some resemblancewith the early Cretaceous S. roemeri
DESHA YES, 1842 and S. gibbosus D'ORBIGNY, 1847 of west Europe, but slightly
differs in less developed primary ribs.
Nearly complete shell is 50 mm long,
58.5 mm high, 16 mm deep and has L/H=0.85. Umbo lies at about 27 mm behindanterior end, that is, a little anterior tothe middle of shell.

Family Plicatulidae WATSON, 1930
Genus Plicatula LAMARCK, 1801
Plicatula sp. aff. P. hanaii HAY AMI, 1965
Plate 3, Figures S~7Compare:1965a. Plicatula hanaii HAYA:VIl, p. 322, pI. 47,
figs. 1-3.

Description :-Shell medium in size, alittle inaequilateral, inaequivalve, variable
in shape but usually ovate; higher thanlong, ranging from 24 to 45 mm in lengthand from 34 mm to 50 mm in height;
hinge consisting of two divergent cardinal teeth in each valve, intervening aresilifer pit at the center of hinge plate,that of left valve bounded by ridges onboth sides; posterior adductor muscle
scar large, circular, lying a little posterior to the middle of shell, anterior
one not observed; left valve more convex
than the right, consisting of inflated
umbonal half and less convex ventral
part, the latter of which is sculptured
with eleven, weak radial ribs arranged
at wide interval; right valve nearly flat,
sculptured with irregular radial ribs

broader than those of left valve andvery weakly nodose.
Remarks and comparison :-Shell isfairly thick being about 5 mm and insome cases bored by organisms. Convex
umbonal half of left valve is considered
to correspond to attachment area ofright valve judged from the recent
species. In Japan one Triassic speciesof Plicatula (P. hekiensis NAKAZAWA,
1955), five Jurassic species (praenipponica
HA YAMI, dichotomocosta. TAMURA, aff.
dichotomocosta TAMURA, subcircularis
HA YAM I and yatsuiiensis TAMURA) andtwo Cretaceous ones· (kiiensis HAY AMI
and hanaii HAY AMI) have been described.
Among them P. kiiensis, P. praenipponica,
P. dichotomocosta and P. aff. dichotomocosta are easily distinguished from thepresent species in close-set, strong radialribs. P. hekiensis and P. subcircularis
also differ in spinose reticulate surface
sculpture.
Plicatula hanaii, though only left valve
is known, is very similar to this species
in shape, size and hinge character, butdiffers from the latter in having central
crenulation and smaller size.. Further
comparison is impossible due to the lackof right valve of hanaii.
Measurements:valve

lengthheight

L/H

Right
Left
Left
Left

24.0
37.0
27.0
4S.0

34.0
SO.O
40.0
39.S

O. 71
0.74
0.69
1.13

depth
9.S

Plicatula sp. indo
Plate 3, Figure 8

There is a left internal mold which considerably differs in outline from thepreceding species. Shell is roundly crescent, extending posteriorly. Hinge is of

699. Cretaceous Bivalves from Shimanto Terrain

25

Plicatula-type. It is not certain whether
this is a varietal form of the preceding
species or not.

Subfamily Exogyrinae VYALOV, 1936

Superfamily Ostreacea

Subgenus Amphidonte FISCHER DERAFINESQUE, 1815

W ALDHEIM, 1829

Family Ostreidae RAFINESQUE, 1815

Amphidonte (Amphidonte) sp. ct. A.

Genus Ostrea LINNE, 1758

subhaliotoidea (NAGAo)

Ostrea sp. ind

Plate 3, Figures 1-4

Plate 3, Figures 9, 12

A complete left internal mold andseveral incomplete shells are observable.
A complete one shows suboval outline
meridionally elongated and gently inflated. Ligament area is relatively narrow provided with a shallow, wide, indistinct ligament pit. Presence of radialribs in left valve is suggested by plication along posterior margin. Right valve
is nearly flat, sculptured with concentriccostae only. Identification is difficult
due to poor materials.

Genus Rastellum F AUJAS-SAINTFOND, 1799
Rastellum? s. I. sp. indo
Plate 2, Figure 7

Only a convex marginal part ofstrongly plica ted shell is at hand. It isvery difficult to determine even generically based on such fragmentary specimen. However, the characteristic plication of the shell margin reminds one ofthat seen in strongly plicated oysters,such as Rastellum S. S. or its subgenus
Arctostrea, and the species is tentatively
referred to Rastellum s.1.
Family Gryphaeidae Vy ALOV, 1936

Genus Amphidonte FISCHER DEW ALDHEIM, 1829

Compare:1934. Exogyra subhaliotoidea NAGAO, p. 203,
pI. 30, figs. 1-4.
1965a. Amphdonte (Amphidonte) subhaliotoidea:
HAY A:>"II, p. 343, pI. 50, figs. 6-9; pI. 51,
figs. 1, 2.
1967. Amphidonte (Amphionte) .subhaliotoidea:
HAYAMI and KAWASA\\,A, p. 78, pI. 9,
fig. 5.
1972. Amphidonte (Amphidonte) subhaliotoidea :SHIKAl'vlA and SUZUKI, pI. 5, figs. 10-14.

Description :-Shell relatively small,suboval, inaequivalve, inaequilateral, spirogyrate backward, higher than long,test fairly thick, provided with no radial
ornament. Left valve moderately inflated having sharply rounded spiral keel
along anterior margin which is broadly
rounded;posteriormarginnearlystraight or a little arcuate' with concaveside backward, not raised; umbonal
portion not well preserved, ligament area
relatively short, elongated along dorsal
margin forming shallow groove. Right
valve a little inflated along weak, roundedspiral keel and nearly flat in posterior
part; ligament area short and almost
flat; anterior margin well rounded, posterior margin weakly curved with convex
side backward; adductor scar being large
and ovate lying a little posterior to the
middle of shell.
Comparison:- The described species is26

Keiji NAKAZAWA, Fujio KUMON and Katsumi KIMURA

most allied to Amphidonte (Amphidonte)
subhaliotoidea (NAGAO) reported from the
Miyako Group, the Inubo Formation of
Choshi Group and from the Lower Cretaceous in Shikoku, which is only one
known species of Amphidonte s. s. inJapan, but slightly differs from thelatter in smaller size and absence ofchomata along shell margin.

Order Veneroida ADAMS andADAMS, 1856
Superfamily Crassatellacea
FERUSSAC, 1882

vation of the hinge. However, thisspecies may belong to the genus Astarte
in general outline and marginal crenulation. It is similar to Astarte aft. shinanoensis Y ABE and NAGAO described by
HA YAMI (1965b, p. 94, pI. 9, fig. 1; pI. 14,
fig. 9) from the upper Neocomian Hanoura
Formation in Shikoku and A. akatsui
HAY AMI (1965b, p. 95, pI. 9, figs. 2-5; pI.
14, figs. 10, 11) of the Albian Yatsushiro
Formation in Kyushu in transversely
elongate form and mode of crenulation.
Systematic position uncertain
Bivalvia, gen. et sp. nov. indo

Family Astartidae D'ORBIGNY, 1884

Plate 3, Figure 11

Genus Astarte SOWERBY, 1816

This unique bivalve is represented bya left internal mold with external moldof marginal part. Shell is suboval inshape, 37.0 mm long, 45.0 mm high and14.0 mm deep with thick test reachingat least 10 mm near the margin. Surface
is covered by relatively strong growthlines of irregular strength. Hinge consists of two cardinal teeth, two cardinalsockets and a large socket-like depression along the posterodorsal margin.
Anterior cardinal tooth is stout, trigonal
and pointed; posterior one strong andelongate. Cardinal sockets are trigonal
and deep, each situated anterior to thecardinal tooth respectively. Socket-like

Astarte? sp. indo
Plate 3, Figure 13

The present species is represented by aleft internal mold which preserves impressions of a trigonal cardinal toothand a socket. It is suboval in shape,
25.0 mm long, 21.0 mm high and 6.5 mm
deep in the internal mold and has minutecrenulation along the margin and a subcircular posterior adductor muscle scarat posterodorsal position of the shellinterior.
It is difficult to determine
even generically, because of poor preser-

Explanation of Plate 2
1-6.

7.

Spondyills sp. aff. S. decoratlls NAGAO
1. External gypsum cast of left valve, JM. 11294.
2. Rubber-compound cast of left valve, 2a: hinge area, 2b: dorsal view, JM. 11295.
3. External gypsum cast of left valve, 3a: side view, 3b: anterior view, 1M. 11296.
4. External rubber-compound cast of left valve, 1M. 11297.
5. External mold of left valve (Sa) and the rubber-compound cast (5b), 1M. 11298.
6. External gypsum cast of marginal part of right valve, 1M. 11296.
Rastellllm? s.l. sp. ind., external gypsum cast, JM. 11299.
(All in natural size. Photo by K. NAKAZAWA.)

NAKAZAWA et al.:Cretaceous fossils from Shimanto terrain

Plate 2

2b

,,

,,

,
\

\
\

\

\
\

)
/

/
./

4

/

3a

6

1b

5b

699.

Cretaceous Bivalves from Shimanto Terrain

depression is large and elongate-oval,
sculptured with vertical crenulation. It
is not certain whether this is a real
socket receiving a tooth of the opposite
valve or not, because of its peculiar shapeand serration. If this is a ligamental
recess, ligament is internal. Lateral
tooth or socket is seemingly lacking and,if present, completely reduced. Posterior
adductor muscle scar is subcircular, large,
situated at the middle of posterior halfof the shell; anterior one is considered
to be small, lying close to the anteriorcardinal socket.
The thick and tall shell provided withrobust cardinal teeth and sockets remind
one of some megalodontid species, suchas Neomegalodon GUEMBEL, 1863, andPachymegalodon GUEMBEL, 1862, but thehinge characters and mode of muscle
scar are different. Megapraeconia CHAVAN, 1952 of veneroids is somewhat
similar to the present species in outline,
thick shell, and strong dentition, but also
distinguishable in musculature and dental
formula. No comparable species could befound. More materials are required forfull description and comparison.
References
AMANO, M. and MARUI, N. (1958): On the
new species of Spondylus from the Cretaceous formation in Nagano Prefecture.
Kumamoto Jour. Sci., Ser. B, vol. 3, no.
1, p. 27-30.
HASHll\IOTO, I. (1968): Geology of the Hida·
kagawa Group in the Yura-Gobo area,
Wakayama Prefecture. Earth Sci. Rep.,
Fac. Gener. Educ., Kyushu Univ., no. 15,
p. 57-66.
- - (1971): The Hidakagawa and lnami
Groups in the western coastal area of Kii
Peninsula. Mem. Geol. Soc. Japan, no. 6.
190-191.
HAYAMI, I. (1959): Lower Liassic lamellibranch fauna of the Higashinagano for-27

mation in West japan. Jour. Fac. Sci.,
Univ. Tokyo, Sec. 2, vol. 12, no. 1, p. 3184.
- - (1965a) : Lower Cretaceous marine pelecypods of japan, part 1. A1e11l. Fac. Sci.,
Kyushu Univ., Ser. D, vol. 15, no. 2, p.
221-349.
- - (1965b): Ditto, part 2. Ibid., vol. 17,
no. 2, p. 73-150.
- - (1975): A systematic survey of the
Mesozoic Bivalvia from japan.
Univ.
Mus., Univ. Tokyo, Bull., no. 10, 249 p.
HAYA~'il, 1. and KAWASA\\-A, K. (1967): Some
Lower Cretaceous bivalves from Shimatogawa Group of south Shikoku. Trans.
Proc. Pal. Soc. Japan, N. S., no. 66, p.
73-82.
Klsl-lu SHIMA"ITO RESEARCH GRO!;P (1975):
The Development of the Shimanto Geosyncline. Problems on geosynclines in Japan. Assoc. Geol. Collab. Japan, Monogr.,
no. 19, p. 143-156. (in japanese with English abstract)- - (1977): The Hidakagawa Group in theSouthern Part of the Ryujin Village, Wakayama Prefecture-The study of the
Shimanto Terrain in the Kii Peninsula,
southwest japan (part 8). Earth Sci. (Chikyu Kagaku), vol. 31, no. 6, p. 250-263.
(in japanese with English abstract)
KUMON, F. (1976) : Stratigraphy and sedimentology of the Shimanto Complex in thesouthern part of Tokushima Prefecture.
Master thesis of Kyoto Univ. (MS).
MIYAMOTO, T. (1976): Comparison of theCretaceous sandstones from the Chichibu
and Shimanto Terrains in the Odochi
area, Kochi Prefecture, Shikoku. Jour.
Geol. Soc. Japan, vol. 82, no. 7, p. 449462. (in japanese with English abstract)
MOROZU~II, Y. (1970): Upper Cretaceous Inoceramus from the Shimanto belt of theKii Peninsula. Bull. Osaka Mus. Nat.
Hist., no. 23, p. 19-24.
NAGAo, T. (1934): Cretaceous Mollusca from
the Miyako district, Honshu, japan. Jour.
Fac. Sci., Hokkaido Imp. Univ., Ser. 4,
vol. 2, no. 3, p. 177-277.
NAKAzAwA, K. (1955) : A study on the pelecypod-fauna of the Upper Triassic Nabae

28

Keiji NAKAZAWA, Fujio KUMON and Kats'/,~mi KIMURA

Group in northern part of Kyoto Prefecture, Japan. part 3, Halobiids and others.
Mem. Fac. Sci., Kyoto Univ., Ser. B, vol.
22, no. 2, p. 243-260.
- - (1973): Several problems of the Shimanto geosyncline. Symp. Shimanto Ceosyncline, Wakayama Univ., p. 125-132. (inJapanese)
NOIIDA, S. (1966): Study on the Mesozoic
geology in the upper course of River
Aritagawa. Grad. thesis of Kyoto Univ.
(MS).
SAKA, Y. (1968): Upper Cretaceous Futakawa
Formation iri the Shimizu'-machi District,
Wakayama Prefecture, Southwest Japan,
with special reference'to the folding
structures. Sci. Rep. School Educ., Waseda Univ., Ser. Nat. Sci., vol. 17, p. 125147.
SHIKAMA, T. and SUZUKI, S. (1972): Stratigraphy and tectonic development of Choshi Peninsula, Chiba Prefecture. Sci. Rep.
Yokohama Nat. Univ., Sec. 2, no. 19, p.
133~157. (in Japanese with English abstract)
SHINOAKE, S. (1958) : Fossils from the Shim-

anto Zone of Tokushima Prefecture. jour.
Ceo!. Soc. japan, vol. 64, no. 749, p. 95-96.
(in Japanese).
STENZEL, H. B. (1971): Oysters. In Moore,
R. C. (ed.), Treatise on Invertebrate Paleonto Part N, Mollusca 6, Bivalvia, vol. 3;
N953- N1224.
T Al'vlURA, M. (1959) : Taxodonta and Isodonta
from the Jurassic Soma Group in North
Japan. Trans. Proc. Pal. Soc. japan, N. S.,
no. 37, p. 223-229.
- - (1960) : Upper Jurassic Pelecypods fromthe Torinosu Group in Shikoku, Japan.
Mem. Fac. Educ., Kumamoto Univ., vol. 8,
p. 227-244.
TA:-:AKA, K. (1974): Cretaceous paleocurrent
directions in the Yuasa District, Wakayama Prefecture, Japan. Ceol. Surv. Japan. lv[onth. Rep., vol. 25, no. 3, p. 15-28.
(in Japanese with English abstract)
TASHIRO, M. (1976): Bivalve faunas of theCretaceous Himenoura Group in Kyushu.
Pal. Soc. japan,' Spec. papers, no. 19, 102 p.
VISIIER, G. S. (1969) : Grain size distributions
and depositional processes. jour. Sedi~
ment. Petro!., vol. 39, no. 3, p. 1074-1106.

Explanation of Plate 3
Amphidonte (Amphidonte) sp. d. A. subhaliotoidea (NAGAO)
1. Internal mold (la) and the gypsum cast (lb), JM. 11300.
2. Internal gypsum cast of right valve JM. 11301.
3. Rubber·compound cast of right valve, showing umbonal part, x 1.5, JM. 11302.
4. Internal mold of right valve, x 1.5, JM. 11303.
5-7. Plicatula sp. aff. P. hanaii HAYAMI
5. Internal gypsum cast of right valve, JM. 11304.
6. Internal rubber-compound cast of left valve, JM. 11305.
7. External rubber-compound cast of right valve, JM. 11306.
8.
Plicatula sp. ind., left internal mold, JM. 11307.
9, 12. Ostrea sp. indo
9.. Left internal mold, JM. 11308.
12. External rubber-compound cast of right valve, JM. 11309.
10. Calamophyllia sp. ind., internal and external molds, x 1.5.
11.
Bivalvia, gen. et sp. nov. ind., internal rubber-compound cast of right valve with othershell, JM. 11310.
13.
Astarte? sp. ind., right internal mold, x 1.5 1M. 11311.
(All in natural size excepting Figs. 3, 4, 10 and 13. Photo by K. NAKAZAWA)
1-4.

NAKAZAWA

et al.: Cretaceous fossils from Shimanto terrain

Plate 3

3
1b

la

5

8

10

699. Cretaceous Bivalves from Shimanto Terrain
Doganaro :g: 'r ~n,Nonoshiri!l!fk JJL,
Kanaya ~~,Yuasa ~~,
Yukawa ~JII,
Yungawa ~TJII

Kuratani ~:fr,

29
Shimizu ffl<7./(,

f!!imS*, *c.{jl-~~gg7J+*~I::l'§:.I: I) Bjj£*c.~WI1=ttJ't(1)i£:tf:j: ;fp~Ll!J!il<il'J'7./(lDJ(1)~JIIJIl
TiifL ~JIIJf3liij;:'5.1: f) Spondylus aff. decoratus, Plicatula aft. hanaii, Amphidonte d.
subhaliotoidea, Ostrea sp. tJ: c'(1)=ttJ't~, ~ Iv:::: Camalophyllia sp. 7'J~geJi!. ~ ht-:o =tt
J'tlt:gil~(1)t(1)t;::A!if.!H-" ~f\;;ftilBjj£*c.c7,..tJ:~h7.>o JJW1:, 1tfi', 1iIDfi't'£(1)=tXJ'tz.;t:f4' c L-, :::: < ~Hro:(1)~m'bj~ vn, 7.>0 ;: hIUj;:'5(1):ltfllt~i¥JliJf~7'J' I? t 3Z:t#~ h7.>o )iiJi1ll
It~~i~\,,;ttg[tiJ#411(1):ltu~~-c:·i!S7.>7'J;, ;:(1).I:? tJ:~i'fjjI1(1);!1l!.~(1)fHElt, WJi;'l;;;ttgj::I) 1;::.1: 7.>t(1)-C:~~<, w7./(.(1)ffiMi¥JR~K.l:7.>t(1)cM.L-~oTrans. Proc. Palaeont. Soc. Japan, N. S., No. 113, pp. 30-44, pIs. 4-7, April 30, 1979

700.

NOTES ON LEWESICERAS AND NOWAKITES (PACHYDISCIDAMMONITES) FROM THE CRETACEOUS OF HOKKAIDO*(STUDIES OF THE CRETACEOUS AMMONITES FROM HOKKAIDO
AND ::3AGHALIEN-XXXVI)TATSURO MATSUMOTO
c/o

Department of Geology, Kyushu University 33, Fukuoka 812

Abstract. This is the first description of Lewesiceras and Nowakites from theCretaceous of Hokkaido. It comprises four new species which are allied to L. rhoda.
nicum (ROMAN and MAZELAN), L. elmii COLLIGNON, N. lemarchandi (DE GROS·SOUVRE) and N. tallavignesi (D'ORBIGNY), respectively. The reasons why the~e twogenera are rare in Hokkaido are discussed in connexion with the evolutIOnaryhistory of the family.

me, through Mr. Y. FUJISHIMA, an interesting vascoceratid ammonite fromthe Hobetsu area (MATSUMOTO and MURAMOTO, 1978) and, furthermore, gave an
information to my inquiry by sending
several associated specimens, in which I
noticed an example of Lewesiceras. Mr.
Yoshitaro KAWASHITA of Mikasa alsokindly sent me an ammonite from the
Ashibetsu area which he thought possibly
a Fagesia. Actually this was not a vascoceratid but is another example ofLewesiceras.
An example of Nowal?ites has long
been in Mr. Tatsuo MURAMOTO'S collec·
tion, but is incompletely preserved. Another example of the same genus was in
my own collection from the Yubari area,
which was, however, erroneously listed
as a species of Mesopuzosia (MATSUMOTO
and HARADA, 1965, table 3).
On the basis of these specimens asystem a tic description is given below,
with some remarks on the two genera.
Repositories of the described specimens

Introduction
Fossils belonging to the Pachydiscidae
occur fairly commonly in the Upper
Cretaceous of Japan and South Saghalien.
They belong to the genera Anapachydiscus,
Eupachydiscus, Canadoceras, Patagiosites,
Pachydiscus and some bituberculate offshoots, Menuites, Uralwwites, and Teshioites (MATSUMOTO, 1954a, 1955). Theycame mainly from the strata of Santonian
to Maastrichtian ages. For some reasons
little has been known from the Coniacianand older rocks. It was strange that no
examples of Lewesiceras and Nowakites
were reported from Japan, while they
are fairly common in Europe and someother regions.
For years, I sought them in vain fromthe Cretaceous of Hokkaido. The present
discovery happened unexpectedly, while I
was collecting vascoceratid ammonites.
Mr. Tsutomu SATO of Yubari kindly sent

* Received Oct. 11, 1978; read June 3, 1978
at Tsukuba.

30

700.

Notes on Lewesiceras and Nowakites

are Geological Survey, Hokkaido Colliery
and Steamship Co., Yubari [HCS], Department of Geology, Kyushu University[GK], and other private collections which
would eventually enter into certain
museums.
Before going further, I thank Messrs.
T. SATO, Y. KAWASHITA and T. MURAMOTO, who provided me with interesting
specimens for this study. Drs. I. HA YAMI,
H. HIRANO, K. TANABE, Messrs. H. HONDA,
Y. FU]ISHIMA and K. MURAMOTO helped
me in. various ways.
This is a contribution to the IGCP
Project Mid-Cretaceous Events.
Systematic Description
Family Pachydiscidae SPATH, 1922
Genus Lewesiceras SPATH, 1939
Type-species: - Ammonites peramplus
MANTELL, 1822
Diagnosis: - Shell moderate-sized tolarge, variably involute, with rounded or
depressed whorl-section, but may be higher whorled in later stages. Periodic constrictions better marked on inner whorls,
associated with major ribs and strong
umbilical tubercles. Ribs of various
length and strength, more or less projected on the venter, generally becoming
weaker on the last part. Suture typicallyless deeply incised than in Anapachydiscus,

31with rather massive elements; E of moderate length, tripartite long L, bipartite
lateral saddles, small but erect U2, descending auxiliaries, an.d narrow internal
elements.
Discussion:-As WRIGHT (1957, p. L 377)
has suggested, Lewesiceras is presumably
a descendant of Eopachydiscus. I haveseen a probable example of Eopachydiscus
in Dr. SARKAR'S collection from the
Cenomanian of India, which can connect
the range of the two genera.
The type-species and its allies arecharacterized by a comparatively lesscomplex suture, as exemplified by that ofLewesiceras sharpei (SPATH) (see BILLINGHURST, 1927, fig. 2) (here drawn, Fig~
1) and that of L. mantelli WRIGHT and
WRIGHT. These are undoubtedly distinguished from a finely and deeply incised suture of Pachydiscus ZITTEL (seeREDTENBACHER, 1873, pI. 27, fig. 5a-c) orthat of Anapachydiscus Y ABE and SHIMIZU(see Y ABE and SHIMIZU, 1921, pI. 9, fig. 2)or that of Eupachydiscus SPATH (seeREDTENBACHER, 1873, pI. 29, fig. Ib).
The stems of L and other elements
are much narrowed in the latter group,
whereas they are moderately broad in
the former. There is, however, gradation in the degree of incisions between
typical patterns. Certain species whichhave been assigned to Lewesiceras, suchas "L." anapadense (KOSSMAT) (1898, pI.
14, fig. 2) and L. beantalyense COLLIGNON

5",,,,

Fig. 1. External suture of Lewesiceras sharpei (SPATH).
8M. C 32290 from Chalk Rock of England. (T. M. delin.)32

Tatsuro MATSUMOTO(1955, pI. 2, fig. 3), have moderately deeply
incised sutures.
The ribbing also varies between species.
The type and the allied species ofAnapachydiscus [A. fascicostatus (Y ABEand SHIMIZU), A. sutneri (YOKOYAMA) etc.]
have finer and weaker ribs than those ofLewesiceras, but there is no remarkabledifference in the degree of fineness orcoarseness of the ribbing between somespecies. For example, L. koluturense(STOLICZKA) (1865, pI. 64, .fig. 3) has nearlyas fine and numerous ribs as those of A.
fascicostatus and is only distinguished byits sharper ribs and less complex suture.
Anapachydiscus arrialoorensis (STOLICZKA)(1865, pI. 64, fig. 1), on the other hand,
has as coarse ribs as those of L.
rhodanicum (ROMAN and MAZERAN) (1913,
pI. 1, fig. 10), but its suture is as complex
as that of A. fascicostatus.
I presume that Anapachydiscus andprobably also Eupachydiscus may' havebeen derived from Lewesiceras, as isstrongly suggested by the species to be
described below. Furthermore, Pseudojacobites SPATH, 1922 and Pachydiscoides
SPATH, 1922 are regarded as offshoots ofLewesiceras (see WRIGHT, 1957, p. L 377).
Therefore, Lewesiceras probably represents a fundamental stock of the Pachydiscidae.
Inciden tally, "Lewesiceras"
anapadense (KOSSMAT) has ventrolateral
tubercles but no median ventral ones on
the preserved last half whorl. As the
body-whorl is incompletely preserved
even in its lectotype (here designated,
GSI. 260, STOLICZKA, 1865, pI. 65, fig. 1;
KOSSMAT, 1898, pI. 20, fig. 2), I think it
better to assign this species temporarily
to Pseudojacobites than to establish a new
genus for it at this moment. This species
is closely allied to Lewesiceras mantelliat an immature stage and can be regarded as representing a transition from
Lewesiceras to Pseudojacobites.

Lewesiceras kawashitai sp. nov.
PI. 4, Fig. 1; Text-fig. 2

Material:-Holotype, M. KAWASHITA'S
Collection, a well preserved fossil, from
Kami-Ashibetsu of central Hokkaido.
Another small specimen in T. MURAMOTO'S Collection from the Ikushumbetsu
area (central Hokkaido), may be an immature example of the present species.
SPecific characters :-Shell of moderatesize, globose in aspects, moderately involute, overlapping about a half of theinner whorl immediately outside the rowof tubercles, with an umbilicus of moderate size (35 percent of diameter). Whorlcoronate -in section, much broader thanhigh, with steeply inclined, high umbilicalwall, subrounded shoulder· and broadly
rounded venter. The shoulder combines
the umbilical one concurrently with theventrolateral one.
Numerous ribs of unequal length andstrength. Every fourth or fifth is the
major rib, which is provided with a strong
tubercle at the shoulder and accompanied
behind with an indistinct constriction on
the septate whorl. Secondary ribs areintercalated or branched from the major
ones near the tubercle. Some of them
are long enough to reach the shoulder
where they may be slightly elevated ornot. Ribs are as a whole rather crowdedwith somewhat irregular distance. They
are nearly rectiradiate or show a very
gently forward curvature on the venter.
The major rib is slightly rursiradiate on
the umbilical wall. On the body chamber
the ribs are somewhat strengthened andbecoming slightly more distant. Some of
the ribs are somewhat narrowed andlowered on crossing the median line ofthe venter. There are 12 major ribs on
the preserved last whorl, of which 4 areon the preserved part (about 90°) of the700. Notes on Lewesiceras and Nowakites
body chamber. The major· ribs are
somewhat more numerous on the inner
whorl than on the outer one, but thechange is gradual.
The suture is moderately deeply incised.

33

The stems of Land U 2 are not so muchnarrowed as in those of Anapachydiscus
but those of the first and the second
lateral saddles are considerably narrowed.

Measurements (in mm) of L. kawashitai sp. nov.
Specimen

DiameterUmbilicus

HeightBreadthB./H.

Holotype89.0(1)(intercostal)

30.0(.34)

34.0(.38)
32.0

64.0(.72)
58.3

1.88
1. 82

20.0(.30)

28.0(.42)

48.0(.73)

1. 75

"

For comparison
L. elmii (holotype) * 67.0(1)(* measured from COLLIGNON, 1965b, pl. 429, fig. 1778; H: 0:038(0.57) in his explanationof plate was probably misprinted.)

10m",'----'

Fig. 2. Lit~esiceras kawashitai sp. nov.
Diagrammatic sketch of holotype. a: iitteral view, b: frontal"view,c : external suture Ii.t' S:· (T. M. delin.)

:34

Tatsuro MATSUMOTO

Companson :-Although only a single
specimen (holotype) and a comparable
smaller one are available at present, theobserved characters are distinct enoughto establish a new species.
This species resembles Lewesiceras elmii
COLLIGNON (1965b, p. 36, pI. 429, figs. 17771778), from the middle part of the Coniacian in Madagascar, in th.e depressed
whorl, broadly rounded venter and general aspects of ornamentation, but differs
in its still broader whorl with a coronate,rather than a semi-lunate section, andthe less projected curvature of the ribs.
The holotype of L. kawashitai has abroader umbilicus than that of L. elmii.
The largest of the three illustrated specimens from Madagascar (COLLIGNON, 1965b,
pI. 429, fig. 1779) has an umbilicus aswide as the Hokkaido specimen, but its
ribs are coarser and more distant withfewer secondaries than L. kawashitai andalso typical L. elmii.
As the suture was neither well illustrated nor described in COLLIGNON'S atlas(1965b), the exact comparison is difficult.
If a sufficient number of specimens wereavailable in both Japan and Madagascar,whether the distinction is specific orsubspecific could be decided. In thepresent knowledge it is better to treat
the present species as distinct, becauseof its olcostephanitoid aspect and its
diagnostic suture.
In the appearance of the shell-form andornamentation, this species looks to be
somewhat similar to Polyptychites polyptychus (KEYSERLING) of the Olcostephanidae and Teloceras blagdeni (J. SOWER BY)
of the Stephanoceratidae and Fagesia
superstes (KOSSMAT) of the Vascoceratidae. This is of course superficial similarity or homoeomorphy and the difference of families is clearly shown by the
sutures. Also some difference in. themode of branching or intercalation of theribs is noticed, if carefully examined.
The suture of L. kawashitai is moredeeply incised with narrower stems of
the elements than in typical species ofLewesiceras (e. g. L. peramplus or L.
sharpei), but is less so than in typicalAnapachydiscus.
Occurrence:- The holotype was obtained by Y. KAWASHITA at a point about
2km downsteam from the Kami-Ashibetsu
dam on the floor of the River Ashibetsu
from a rolled or fallen calcareous nodule.
At and near this point along the valleyof the Ashibetsu River the Coniacian partof the Upper Yezo Group is extensively
exposed, forming a synclinorium (seeYOSHIDA and KAMBE, 1955).
Another comparable smaller specimen
was obtained by T. MURAMOTO in a
floated calcareous nodule of the Ikushumbetsu River in an area adjacent to thesouth of the Kami-Ashibetsu area. It is
presumed to have been derived from somewhere in the Upper Yezo Group (Upper
Turonian-Santonian). Thus the precise
stratigraphic position of the present
species is uncertain, but the derivationof its holotype from the Coniacian is themost probable.
Lewesiceras satoi sp. nov.
PI. 5, Fig. 1; Text-fig. 3

Material :-Holotype, HCS. No. 187. from
Osawa, paratype, HCS. No.3, from Nutapomanai, both Tsutomu SATO'S Collection
from the Hobetsu area, Hokkaido.
Specific characters :-Shell of moderate
size and moderately involute, about ahalf of the inner whorl being overlappedby the outer one; umbilicus of moderate
width (about 30% of diameter). Whorls
rounded, somewhat broader than high,and broadest in the lower part slightly
outside the rounded umbilical shoulder.

700. Notes on Lewesiceras and Nowakites
Ribs numerous, of various length, becoming coarser on the adult body-chamber,gently concave on the flank and gently
to moderately projected on the venter.
On the outer whorl every fifth or fourth
rib is longer and slightly stronger than·others and provided with an umbilicaltubercle, which is generally of moderateintensity and rounded at the base but on
the preserved last part bullate. The
major rib is accompanied with a weak-constriction in front of it. On the early
half of the last whorl (i. e. the late partof the septate whorI), another rib starts
from the umbilical tubercle behind the
Measurements (in mm) of L. satoi sp. nov.
Specimen35

major one. On the inner whorl every
second or third rib is longer and provided
with a bullate umbilical tubercle. There
are 10 or 11 umbilical tubercles on theouter whorl and more numerous ones on
the inner whorl.
Suture of general pachydiscid pattern.
L and the saddles on both sides of L
ha ve narrower stems than in Lewesiceras
sharpei (SPATH) (see BILLINGHURST,1927,
text-fig. 2; also Fig. 1 in this paper), but
the stems of Land U2 are not so narrowed as in Anapachydiscus fascicostatus(Y ABE) (Y ABE and SHIMIZU, 1921, pI. 9,
fig. 2).

DiameterUmbilicus

HeightBreadthB./H.

Holotype
124.0(1)" (-180°)
Para type
57.0
L. rhodanicum 75

39.6(.32)

52.0 (. 42)
35.0
25.2 (. 44)
32.5 (. 43)-30.5x2=61(.48)
44.5-15. Ox 2=30(. 53)
46 (. 61)

1.17
1. 27
1. 20
1. 38

16.6(.29)
17.5 (. 23)

,,
,,

··

~

Go

fO"""

Fig. 3. Lewesiceras satoi sp. nov ..
Diagrammatic sketch of holotype. a: lateral view, b: costal whorl·section
at Q, c: external suture at S. (T. M. de/in.)

36

Tatsuro MATSUMOTO. Remarl,s:- The holotype is represented
by an internal mould, without shelllayers in most parts. Only an inner shelllayer is preserved on some portions of
the living chamber. It shows minor
wrinkled structure and also minute dotted
structure. The last suture is seen at
about 95 mm in diameter and the living
chamber occupies at least a half whorl.
At about the middle of the living chambera weak umbilical bulla is exceptionallydiscernible at the end of one of the threeribs inserted between the major ribs (seeText-fig. 3).
As the umbilical tubercles on the outerwhorl of the holotype have a roundedbase and are fairly strong even on theinternal mould, the tubercles must havebeen prominent at the top, when theouter shell layer was preserved.
Comparison:-The present species issomewhat similar to Lewesiceras rhodanicum (ROMAN and MAZERAN) (1913, p. 18,
pI. 1, fig. 10), from the Turonian of the
Uchaux basin, France, but it has lessinflated whorls, more numerous and finerribs than that French species. In L.
rhodanicum the tubercles are bullate at
every stage but in L. satoi they have arounded base and probably a prominent
top. The suture was not well describedin L. rhodanicum but the photograph ofthe holotype suggests a less deeply incised suture.
This species closely resembles Anapachydicus deccanensis yezoensis MATSUMOTO (1955, p. 179) (see PI. 7 of thispaper), from the Santonian of Hokkaido
and Saghalien, in the shell-form, ribbing
and tuberculation. The distinction is thatin the latter species the prominent
umbilical tubercles (of deccanensis type)appear earlier and the suture is much
more deeply and finely incised with morenarrowed stems of Land U2 as well as
saddles, as in other species of Anapachy-

discus, e. g. A. fascicostatus (Y ABE) (Y ABEand SHIMIZU, 1921, p. 57, pI. 8, fig. 5; pI.
9, fig. 2) or A. sutneri (YOKOYAMA) (1890,
p. 187, pI. 23, fig. 1). It is possibly considered that A. deccanensis yezoensis may
have descended from Lewesiceras satoi
by developing the strong umbilical tubercles and increase in the complexity ofsutures. More specimens from successive
stratigraphic levels, including Coniacianones, are needed to examine this possibility.
It is also noted that the present species
looks somewhat similar to Eupachydiscus
haradai (jIMBO) (see MATSUMOTO, 1954a,p. 281, pI. 8, fig. 2; pI. 9, figs. 1-3; pI. 10,
figs. 1-3; text-figs. 14-17) from the Santonian and the lowest part of the Campanian of Hokkaido and other regions,but the latter has much coarser andstronger ribs and more complex suturesin the middle and late growth-stages.
Occurrence :-Holotype was obtained by
T. SATO in a floated calcareous nodule
at a point about 100 m downstream fromthe conference with a branch called the
Nutapomanai in the main course of theRiver Hobetsu. Paratype was obtained
also by T. SATO at loco H2074p, in thelower course of the Nutapomanai of thesame Hobetsu area, central Hokkaido.
As the Turonian rocks are exposed wellalong the stream of the Nutapomanai,
the two specimens were probably derived
from somewhere within the Turonian.

Genus Nowakites SPATH, 1922
Type-species :-Pachydiscus carezei DE
GROSSOUVRE, 1894
Diagnosis :-Shell small to moderate insize, moderately involute, with umbilicus
of moderate width; whorl-section circular to suboval, nearly as high as broador somewhat higher than broad. Periodic
constrictions moderate or shallow on

700.

Notes on Lewesiceras. and Nowakites

inner whorls, becoming less distinct onouter whorl. Major ribs behind. the constriction start from weak umbilical bullae;
several ribs of unequal length. between
major ones; constrictions and ribs gently
to moderately projected on venter. Ribs
may be coarsened on outer whorl. Suture
similar to that of. Lewesiceras.
Remarks:- To this genus I refer, besides the type-species, Puzosia lemarchandi
DE GROSSOUVRE, 1894, Sonneratia savini
DE GROSSOUVRE, 1894, Ammonites tallavignesi D'ORBIGNY, 1850, and probably
Ammonites paillettei D'ORBIGNY, 1841.
These are from the Coniacian or Santonian of France and other areas.
Pachydiscus jimboi KOSSMAT, 1898 (holotype GSI. 263, from the TrichinopolyGroup of southern India), is better referred
to Nowakites than to Lewesiceras, because
its whorl is less inflated and frequently
constricted.
Whether Ammonites draschei REDTENBACHER, 1873, from the Alpine Gosau beds
is Nowakites or Canadoceras is a question
to be worked out. COLLIGNON (1955, 1966)
referred it to Nowakites and describedanother allied species, N. mangoldi COLLIGNON, 1966, from the Middle Santonianof Madagascar..
Through the study of two syntypes ofAmmonites fiaccidicosta ROMER, 1852,
from Texas, I have noticed that one ofthem (lectotype) belongs to Nowakites
fiaccidicostus (ROMER) and the other a
new species of Pseudojacobites [P. texanus
MATSUMOTO] (see MATSUMOTO, 1966).
The holotype (GIB. 27), by monotypy, ofAmmonites hernensis SCHLUTER, 1867,
from Grauer Mergel of Westphalia (Germany), is secondarily deformed, but isprobably an example of Nowakites, which
is fairly close to N. lemarchandi but still
more finely ribbed. Unfortunately the
suture is not observable on this specimen.
In this paper two new species are added37

from Hokkaido, of which one is from theConiacian and the other from the middle
part of the Turonian. On this evidence
the range of Nowakites extends down to
the mid-Turonian.
Discussion:-I suggested once (1954b, p.
113) that Pseudopuzosia SPATH, 1926 ofTuronian age could be an ancestor of
Anapachydiscus and Nowakites.
Thatgenus is yet little known, represented
only by P. marlowense (NOBLE), from theUpper Turonian of England, and P. sp.
from a boulder of phosphatised rock at
Sardal (BIRKELUND, 1973), presumably
derived from Upper Cenomanian orTuronian beds. This Scandinavian species
is more involute and less inflated than
P. marlowense and shows some similarity
to Eopachydiscus marcianus (SHUMARD,
1854), from the Upper Albian of Texas, if
it is not so much involute and compressed
as SHUMARD'S species. Its suture, illustrated by BIRKELUND (1973, fig. 10), is
fairly similar to that of Eopachydiscus
laevicaniculatus ROMER in LASSWITZ, 1904.
This suggests me that Pseudopuzosia may
be a smoothing derivative of Eopachydiscus or possibly a smoothed offshoot ofLewesiceras.
Meanwhile, as I discussed in the preceding genus, Anapachydiscus can now beinterpreted to have been derived from acertain subgroup of Lewesicems. Since
Lewesiceras includes so various species
that a certain other subgroup (e. g., represented by L. donovani COLLIGNON,
1965) may have given rise to Nowakites,
acquiring multicostation and reducing
inflation of whorls.
Canadoceras was probably derived from
Nowakites, with enlarging shell, more
distinct multicostation, more distinct
constrictions with strongly tuberculate
major ribs and more complex sutures,with much narrowed stems of the elements by deep incisions.

Tatsuro MATSUMOTO

38

Nowakites yubarensis sp. nov.
PI. 5, Figs. 2-3; Text-fig. 4.

Material :-Holotype, GK. H5872, collected by myself in 1960, from loco Yb
15, Yubari, Hokkaido.
Specific characters :-Shell of moderatesize, with the last septum at about 80 mm
in diameter. Whorl moderately involute,with moderately narrow umbilicus, growing rather slowly; whorl-section subelliptical, somewhat higher than broad,with B./H.=0.85 or so at the septate
stage; flanks gently inflated passing tomoderately arched venter; umbilicalshoulder subrounded ; umbilical wall steep
but low.
Periodic constrictions well-marked on
the internal mould of the middle growthstage, bordered in front by a major rib
which is distinctly elevated at the umbilical shoulder, forming a bullate tubercle.
There are four or five constrictions perwhorl, and on the intervening parts between the constrictions there are numerous ribs, which normally consist ofalternating longer and shorter -ones.
Some of the longer ribs look to beslightly thickened at the umbilicalshoulder but not so distinctly elevated as
the tubercles of the periodic major ribs.
The ribs and the constrictions are nearlyparallel, gently to moderately sigmoidal
on the flank and considerably projectedon the venter. The ribs are fairly fineand dense in early growth-stages, becoming to be of moderate intensity anddensity later.
Suture is of pachydiscid type, withmoderate degree of incision. Lobes andsaddles are moderately narrowed at theirstem.
Remarks:-Only a posterior portion of
the living chamber is preserved. Its
ribbing is not much different from thatof the late part of the septate whorl.
The measurements (below) are on thewhorl of the middle growth-stage.
Comparison:- This species closely resembles Nowakites lemarchandi (DE GROSSOUVRE) (1894, p. 173, pI. 22, fig. 5), fromthe Lower Coniacian of Aude (France),
but its ribs are gently to moderately
sigmoidal on the flank, unlike simply

Fig. 4.

External suture of Nowakites
yubarensis sp. nov.

Measurements (in mm) of N. yubarensis sp. nov.
DiameterUmbilicus

HeightBreadthB./H.

76.0(1)( -90")

20.0(.26)

26(.34)24-22(.29)

0.85
0.85

----

20.5

Explanation of Plate 4
Fig. 1. Lewesiceras kawashitaisp. nov .......................... _. _............ : ..... Page 32
Holotype, from the Ashibetsu area, collected by Y. KAWASIHTA. Two lateral (a, b),
ventral (c) and frontal (d) views, xL Kyushu University (H. HIRANO) photos without
whitening.

MATSUMOTO:

la

Plate ~

Lewesiceras and Nowakites

Ie

700.

Notes on Lewesiceras and Nowakites

projected ribs of the latter. As far as
the holotypes of the two species are concerned, the constrictions are less frequentin ours than in the French species, but
this character could be variable, if numerous specimens were examined. Unfortunately the suture is not known inthat French species, which was assigned
to Puzosia by DE GROSSOUVRE (1894, p.
173).
The holotype of this species was once
(MATSUMOTO and HARADA, 1964, table 3)
misidentified with Mesopuzosia pacifica
MATSUMOTO (1954b, p. 82, pl. 14, fig. 1;
pI. 15, figs. 1-2; pI. 16, figs. 1-3), but thesimilarity is superficial. It has tuberculate
major ribs and pachydiscid type suture.
The suture of M. pacifica is of Puzosia
type (as represented by the fine illustration of KOSSMAT, 1898, pI. 16, fig. 4), having an enlarged and extremely asymmetrically trifid L.
In view of the similarity in suture andother respects, this species should be
brought in comparison with Kossmaticeras
theobaldianum (STOLICZKA), which is
widespread in the Coniacian of the IndoPacific region. In the latter species theribs are less flexuous and more prorsiradiate, the constrictions are more
prominently projected on the venter,cutting obliquely several ribs behind
them, the longer ribs are more frequently
elevated forming bullae at the umbilicalend and the shorter ribs are often so
disposed as being bifurcated from thelonger ones.
Occurrence :-Loc. Yb 15, exposure onleft wall of the creek of Ponhorokabetsu,
about 400m below the dam from the sourceof water supply to Yubari City, in green,fine to medium-grained sandstone ofMember Mk3, Mikasa Formation, slightly,
above the prolific part of Inoc.eramus
hobetsensis NAGAO and MATSUMOTO but
distinctly below that of!: Inoceramus

39

teshioensis NAGAO and MATSUMOTO (seeMATSUMOTO and HARADA, 1964), "middle
part of the Turonian" as defined in Japan(MATSUMOTO, in press).

Nowakites mikasaensis sp. nov.
PI. 6, Fig. 1

Material: - Holotype, T. MURAMOTO
Collection M-1709, from Ban-no-sawa A,
Ikushumbets, central Hokkaid6.
SPecific characters :-Shell fairly large
for the genus, about 140 mm in diameterat the last septum; umbilicus about one
third of the entire diameter. Whorl
subelliptical in section, higher than broadin late growth-stages but probably subcircular and nearly as high as broad inearlier stages, with steep but low umbilical walls, rounded umbilical shoulders,moderately inflated to very gently convex
flanks and rounded venter.
Ribs numerous, weak and of unequal
length on the main part of the septate
whorl; every sixth rib is somewhat
stronger than others, provided with umbilical tubercles, and accompanied by aweak constriction in front of it. On thelast part (about 60°) of the septate whorl
and probably on the living chamber(which is mostly missing in the holotype),
the ribs become coarser and more distant,showing a moderate projection on theventer. Every third rib is major, andprovided with moderately strong tubercles at the umbilical shoulder.
Sutures, as partly observed, fairly finely
and deeply incised for the genus.
Remarks:-The holotype is imperfectly
preserved, especially its whorls of earlystages are badly squashed; also only aposterior portion of its living chamber ispreserved, For a long time I sought invain better preserved specimens. Despitesome deficiency, however, the holotype

Tatsuro MATSUMOTO

40

Measurements (in mm) of N. mikasaensis sp. nov.
DiameterUmbilicus

HeightBreadth

B./H.

140.0(1)45.0 C. 32)

60.0 C. 43)

51. 0 (.36)

0.85

shows distinct characters.. It would bebetter to describe a new species on thisoccasion than to postpone the description.
Comparison; - The holotype of thisspecies is larger than any of the previously described examples of Nowakites
and the suture is deeply and finely incised, resulting in narrowed stems of thelobes and saddles, though. it is partly
observed. Accordingly someone might
consider this species as Canadoceras.
However, I refer it at least tentatively
to Nowakites, because the constrictions
are less well-marked and the umbilicaltubercles on major ribs are less prominent
than in Canadoceras.
The mode of ribbing on the whorl of
the late growth-stage of this species issomewhat similar to that of Nowakites
tallayignesi (D'ORBIGNY) (1850, p. 190)
(holotype figured by COLLIGNON, 1955, pI.
9, fig. 3), from the Coniacian of southwestern France, but the holotype of thatspecies is much smaller and has morerounded whorl than that of the present
species. Again the suture is not clearly
described in N. tallavignesi.
Occurrence ;-Holotype is from an exposure on a small branch A of the Ban-no-sawa a tributary of the River Ikushumbetsu, from a calcareous concretionin sandy siltstone of the Zone of Inoceramus uwajimensis, which is probably
correlated with the Lower Coniacian III
terms of the international scale.

Concluding Remarks
In this paper I have described two
species of Lewesiceras and two species of
Nowakites, which are somewhat allied tocertain hitherto known species from
France, Madagascar and other areas. At
presentevery species is represented byonly one or a few specimens and theimpression that the two genera occur
rather rarely in Hokkaido cannot bedenied. The rarity may partly due toour collection failure but there may besome other reasons
I once attempted to draw a tentative
diagram to show the vertical ranges of
the genera and subgenera of the Pachydiscidae, with presumed phylogenetic
relationships (MATSUMOTO, 1964). Its revised diagram is presented here (Fig. 5),though this is still tentative.

Explanation of Plate 5
Fig. 1. Lewesiceras satoi sp. nov ..................................................... Page 34
Holotype, from the Hobetsu area, collected by T. SATO. Lateral Ca) and frontal Cb) views,
x2/3.
Figs. 2-3 Nowakites yubarensis sp. nov ............................................... Page 38
Holotype, GK. H 5872, from the Yubari area, collected by T. MATSUMOTO.
2. Lateral view of the whole specimen, with much destroyed outer whorl, xl
3. Lateral (a) and ventral (b) views of the inner whorl, xl
Kyushu University CK. TANABE) photos without whitening.

MATSUMOTO : Lewesiceras and Nowakites

Plate 5

41

700. Notes on Lewesiceras and Nowakites
ALBIANCENOMANIANTURONIAN

SANTONIAN

CONIACIANCAMPANIAN

MAASTRICH.

Teshioites •,l Canadoceras

Pseudopuzosia 0...., Patagiosi tes 0

Nowakites!

Pseudojacobites•
Urakawites

Eopachydiscus ;/Lewesiceras

:/-_.

•

EUpachydis~us

I
I\ Tuberodiscoides·

Pachydiscoides'-

I

Menuites -

\

I

i

--

Anapachydiscus

.

.\ \

\.

NeO~aChYdiSCUS\ .

\ \ "Hoepenites".

\\ \ .........

• bituberculate.
0smoothe.d
K3b\. Bayleites

K4aFig. 5.

K4b

K5a

K5b

Neo,desmoceras 0..··· . . . •••.. 1,/pachyaiscus\ pse~domenui tes·
\

K6a

K6b

Diagram showing stratigraphic ranges and phylogenetic
relationships of pachydiscid genera and subgenera.

The origin of the Pachydiscidae isprobably in Desmoceras of Albian age.
Compared with Desmoceras and othergenera of the Desmoceratinae, most of the
Pachydiscidae have larger size, more orless wider umbilicus, coarser or stronger
ribs, which are less or non-sigmoidal, anddistinct tubercles. Some of these characters suggest the adaptation to somewhat
shallower seas than the Desmoceratinae.
In fact, Lewesiceras, Nowakites and Pachydiscoides occur commonly in the sedimentsof the shelf or epicontinental shallow sea
facies. These genera, and also Eopachydiscus and Pseudopuzosia have comparatively less deeply incised, broader lobes
and/or saddles of the septal suture, which
again suggest that their habitats werecomparatively shallow.
Pachydiscid
genera of later ages, such as Anapachy-

discus, Eupachydisclls, Canadoceras, andPachydiscus, have more deeply and finely
incised, complex sutures, with narrowed
stems of lobes and saddles. This suggeststhat these genera of later ages may haveagain acquired the ability of betterswimming in the off-shore seas or thatof going down to moderate depths. Inview of various shell-forms and mode ofornamentation, the habitats of thesegenera must have been diverse, withmultiple ways of adaptation. Speaking
broadly, however, these genera occur
commonly in the regions facing theoceans, although in various kinds offacies.
The above mentioned major aspect inthe evolutionary history of the Pachydiscidae is an answer why Lewesiceras
and Nowakites are rare and no example

42

Tatsuro MATSUMOTO

of Pachydiscoides has been found in the
Cretaceous of Hokkaido and other areasin the Japanese province where shallow
shelf seas were lacking or limited.
Another interesting aspect in theevolutionary history of the Pachydiscidae
in the development of ventrolateral tubercles (and also median ventral ones incertain genera) on the outer whorl ofseveral genera. They are respectively
allied to but usually smaller than certain
normal pachydiscid genera of a nearly
contemporary age. The counterparts are,for example, Pseudojacobites: Lewesiceras,
Tuberodiscoides: Pachydiscoides, Menuites:
Anapachydiscus, Pseudomenuites:! :Pachydiscus, U rakawites: Eupachydis'cUs,,' andTeshioites: Canadoceras. Thisgi\i~s us
an idea that they might repre'sent thedimorphism, with bituberculate form as
microconch, as I have already notified
with rather negative suggestion (MATSUMOTO, 1955, p. 155). In our present knowledge, bituberculate forms are generally
found with much less frequency than thenormal counterparts. Their exact stratigraphic ranges do not strictly coincidewith those of normal ones. There are a
few genera for which no bituberculate
counter parts are found. Nowakites is an
example of such a case, although therelationship of Nowakites flaccidicostus(ROMER) and Pseudojacobites texanus MATSUMOTO could still provoke a debate(see MATSUMOTO, 1966). So far as I haveseen, certain species of bituberculate
pachydiscids are collared or constricted
near the apertural end of the shell but
no lappets have been confirmed. In somespecies bituberculation begins to appear
already on a probably immature shelLI am, thus, still kept to hold my previous
view that the bi- or trituberculation inpachydiscids is evolutionary~i. e. adaptation for certain modes of life, rather thandimorphism, although I would not decidedly deny a possibility of the latter interpretation.
Lastly, another evolutionary aspect isthe smoothing of the shell or reductionof ornaments, as exemplified by Neodesmoceras and Patagiosites. In this paper,
Pseudopuzosia is also interpreted in sucha way, and not considered as ancestral
weakly ornamented form to give rise to
Nowakites.

References Cited
BILLINGHURST, S. A. (1927): On some new
Ammonoidea from the Chalk Rock. Ceol.
Mag., vol. 64, p. 511-518, pI. 16.
BIRKELUND, Tove (1973): A note on Pseudopuzosia sp. from Sardal. Appendix to
BERGSTROM, J. et al. (1973): An extension of Upper Cretaceous rocks to the
Swedish west coast at Sardal. Bull. Ceol.
Soc. Denmark, vol. 22, pt. 2, p. 141-143,
pI. 12.
COLLIGNON, M. (1955): Ammonites neocretacees du Menabe (Madagascar). II.-Les
Pachydiscidae. Ann. Ceol. Servo Mines,
fasc. 21, 98p, 28pls.
- - (1965a): Atlas des Fossiles Caracteristiques de Madagascar (Ammonites), fasc.
12 (Turonien), 82p., pis. 376-413.
- - (1965b) : Ditto, fasc. 13 (Coniacien), 88p.,
pis. 414-454.
- - (1966): Ditto, fasc. 14 (Santonien), 134p.,

Explanation of Plate 6
Fig. 1. Nowakites mikasaensis sp. nov ................................................. Page 39
Holotype, from the Ikushumbetsu area, collected by T. MURAMOTO. Two lateral (a, b)
and ventral (c) views, x 2/3. Kyushu University (K. TANABE) photos without whitening.

700. Notes on Lewesiceras and Nowakites
pis. 455-513.
GROSSOUVRE, A. DE (1894): Recherches surla Craie superieure. II. Paleontologie.
ammonites de la Craie superieure. Mem.
Carte Ceol. Det. Frcnce, 1893, 264 p., 39 pis.
KOSSMAT, F. (1898): Untersuchungen tiber
die stidindisc.he Kreideformation. Dritter
Theil. Beitr. Paliiont. Oesterr.-Ungarns
u. d. Orients, vol. 11 (1897), p. 89-152, pis.
14-19.
LASSWITZ, R. (1904): Die Kreide-ammoniten
von Texas. Ceol. Abhcndl., vol. 10 (n. s.
vol. 6), no. 4, p. 1-40, pis. 1-8.
MATSUMOTO, T. (1954a) : Selected Cretaceous
leading ammonites in Hokkaido and Saghalien. In MATSUMOTO, T. (ed.) (1954):
The Cretaceous System in the JapaneseIsland, p. 243-313, pis. 1-20, Japan Soc.
Prom. Sci., Tokyo (for 1953).
- - (1954b): Family Puzosiidae from Hokkaido and Saghalien. Mem. Fac. Sci.,
Kyushu Univ., sere D, vol. 5, no. 2, p.69ll8, pis. 9-23.
- - (1955): The bituberculate pachydiscids
from Hokkaido and Saghalien. Ibid., vol.
5, no. 3, p. 153-184, pis. 31-37.
- - (1964): Ontogeny and evolution in some
Cretaceous ammonites.
Kaseki (Fossils), no. 8, p. 67-76 (in Japanese).
- - (1966) : Notes on Ammonites flaccidicosta
Rti:l-IER from the Cretaceous of Texas.
Trans. Proc. Palaeont. Soc. Japan, n. S.,
no. 63, p. 294-302, pI. 32.
- - (in press): Biostratigraphic subdivisionof the Cretaceous system in the JapaneseEast Asian province.-Definition and interregional correlation. In KAUFFMAN, E. G.
and HATTIN, D. E. (ed.): The North
Temperate Cretaceous, Dowden, Hutchinson & Ross. Inc.
MATSUMOTO, T. and HARADA, M. (1964):
Cretaceous stratigraphy of the Yubaridome, Hokkaido. Mem. Fac. Sci., Kyushu
Univ., sere D, vol. 15, no .. 1, p. 79-ll5,
pis. 9-11.
MATSUMOTO, T. and MURAMOTO, K. (1978):
Further notes on vascoceratid ammonites
from Hokkaido. Trans. Proc. Palaeont.
Soc. Japan, n. S. no. 109, p. 280-292, pI. 39.
ORBIG:-IY, . A. D' (1840-42):
Paleontologie

43

franfaise.
Terrains Cretaces. Cephalopodes, 662 p., 148 pis. (p. 1-120, 1840;
p. 121-430, 1841; p. 431-662, 1842), Paris.
- - (1850): Prodrome de Pa!eontologie stratigraphique universelle, vol. 2.
REDTENBACHER, A. (1873): Die Cephalopoden
fauna der Gosauschichten in den nordostlichen Alpen. Abhandl. Ceol. Reichsanst., vol. 5, p. 91-149, pis. 166-171.
RtirvIER, F. A. (1852): Die Kreidebildungen
von Texas und ihre organischen Einschliisse, 100 p., 11 pis., Bonn.
ROMAN, F. and MAZERAN, P. (1913): Monographie paleontologique de la faune duTuronien du Bassin d'Uchaux et de ses
dependences. Arch. Musee hist. nat. Lyon,
vol. 12, p. 1-137, pis. 1-11.
SCHLUTER, C. (1867): Beitrag zur Kenntniss
der jiingsten Ammoneen Norddeutschlands,
36 p., 6 pis., Bonn.
SHt;MARD, B. F. (1854): Paleontology. Description of the species of Carboniferous
and Cretaceous fossils collected.
In
MARCY, R. B.: Exploration of the Red
River of Louisiana in the year 1852,
Wash.
SPATH, L. F. (1922): On the Senonian ammonite fauna of Pondoland. Trans. Roy.
Soc. South Africa, vol. 10, no. 3, p. 113147, pis. 5-9.
- - (1926): On new ammonites from theEnglish Chalk. Ceol. Mag., vol. 63, p_
77-83.
- - (1939): Problems of ammonite nomenclature. 6, The genus Pachydiscus ZITTEL.
Ibid., vol. 76, p. 293-296.
STOLICZKA, F. (1863-66) : Ammonitidae, withrevision of the Nautilidae, etc. In BLA!'iFORD, M. F. and STOLICZKA, F. (1861-66) :The fossil Cephalopoda of the Cretaceous
rocks of southern India. Mem. Ceol. Surv.
India, Palaeont. Indica, sere 3, vol. 1, p.
41-56, pis. 26-31 (1863); p. 57-106, pis.
32-54 (1864) ; p. 107-154, pis. 55-80 (1865) ;p. 155-216, pis. 81-94 (1866).
WRIGHT, C. W. (1957) : In MOORE, R.C. (ed.)(1957):
Treatise on Invertebrate Paleontology, Part L., p. L 80-490. Univ. Kansas and Geol. Soc. Amer.
YA[lE, H. and SHIMIZU, S. (1921): Notes

Tatsuro l\!IATSUMOTO

44

on some Cretaceous ammonites from Jap·an and California. Sci. Rep. Tohoku Imp.
Univ., 2nd ser., vol. 5, no. 3, p. 53-59,
pis. 8-9.
YOKOYAMA, M. (1890): Versteinerungen aus
der japanischen Kreide. Palaeontographica,

vol. 36, p. 159-202, pis. 18-25.
YOSHIDA, T. and KAMBE, N. (1955) : Ikushum·
betsu·dake. Expl. Text Ceol. Map Japan,
scale 1: 50,000. 31 p. (in Japanese) +7 p.
(in English) ; 1 map.

Ashibetsu J57JJj.
Ban.no·sawa §(1)tR.
Hobetsu f1I!7JJj.
Ikushumbetsu ~~7JJj.
Kami·
Ashibetsu J:J57JJj.
Mikasa 3~.
Nutapomanai:;t jl ;f-"'?7'1.
Osawa
Ponhoro·kabets.u;f-:/*p;!J"'7.
Sanushibe -Ij-:;t-/"' •.
Yezo::r.'/ (~~).
Yubari:&~*"fIl.

c~tw~i~L!I£*i¥:/{ ')I ~ 7' 1 7-.;!J 7-.f4 7:/-'€: 7'1 r (1) Lewesiceras
Nowakites I;:: "?~'-C :1:l*(1)J:$tl9E:*lqt. Pachydiscidae l;::im1' 7.> 7:/-'€:7' 1 }-ft.. iI'tJ:IJ37i¥:1'7.>il t • t.(1)fiIjj~11£ti""('¥IH!r~.n -c~,tJ:iJ'"'Jt.::.o ~iIi~tw~(1)T -"- - p =-7:/ c:2 =-7 -/7 :/iI'!? m:lt!!(1)n(1)Jl1J1:J {, if:,"'J -C. *'f(1)~{7IJ~ f4}7.> t. C iI~""('~t.::.o t. t.1;::I1 4 :fi!!~~tn... t.::.o .:t.n !?11.
(1) L. elmii COLLIGNON, (2) L. rhodanicum (ROMAN and MAZERAN), (3) N. Lemar·chandi (DE GROSSOUVRE), (4) N. tallavigneii (D'ORBIGNY) I;::M{);'(1' 7.> iI'. IjiH'RH;::mlt7JJj ~.n7.> O)""('iT:fi!!c l....t'::'o gctGl;::~t.::.lJ. fiIjj~(1)~M:. ft!!.~ c (1) I*l{;fi tJ: cl;:: "?~'-C~R l....t'::'o
1;::11,' Pachydiscidae f4(1)jlMt~l1)j!!r~~. *t!CW~~*~~.::t -C~ l.... t..nI;::I*l)ll... -C. #if:
7'f-""('iI,tJ: IJ J: <: i¥:1' 7.> Lewesiceras
Nowakites ii' I:l *""('11 .ltttft:1 i .nl;:: l...iI'.L¥: l... tJ: ~ ,J!![*6.

c~(1)R~~~~~~*.M

P. S. A part of the expenditure for this study was defrayed through the grant(No. 334043) from the Ministry of Education, Science and Culture (Monbusho).

Explanation of Plate 7
Fig. 1. Anapachydiscus deccanensis yezoensis MATSUMOTO ............................ Page 36
Holotype, UMUT. MM 5645 (=GT. 1-2742J. from Sanushibe, Anapachydiscus beds of theUpper Yezo Group in the Hobetsu area, central Hokkaido (H. YABE Coli.) (see MATSU·:MOTO, 1955, p. 179). Two lateral (a, b), ventral (c) and frontal (d) views, x5/8 (Barat the center indicates 10 mm). Early portion of the last whorl is taken out in Fig. la
and Fig. Id to show the inner whorls. University of Tokyo (I. HAYAMI) photos, withwhitening.

MATSUMOTO:

Lewesiceras and Nowakites

Plate 7

45
PROCEEDINGS OF THE PALAEONTOLOGICALSOCIETY OF JAPAN*~ ~ ~[!
01978~ 6 Jj 2 8 t;:: %t1BE#¥:'L' rrtJ:bn t.: fiEfflJ~~ffit~t;::t.;\"1::.
nt.: (1iZf*~) 0~Q)~;{gQ)A· ;JHl1tJ; *~~.

?-:{!UJl5l.. ~ll!t7j'Jt, 'tC.
~~. ~***. :fiJfl l1. t~*~tl~. B**=f*. 3jZJfI~~. ll:t'~~;I;:. ;ifo{t;l;:. ~MtiHf.
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:;R1j[l' 9J.;~(J)=:~j§l (Steinmanella) t;:: '?\" -C ..
................................... . mf\::IEz
Inoceramus balticus BOHM :&(f~J!!f!!!(J)11l;~t;::'?\"-C(J)~~t .................... , ... ffm~z

Notes on Inoceramus japonicus from theUpper Santonian of Japan ................. .
· ........... NODA, M. and MATSU:\WTO, T.
Some new bivalve species from the lower
Gyeongsang Group, Korea ................. .
· ....................... Seong Young YANG
"Ostrea" konbo (S!lU[!) (J)1:.:/it~~.!:: ID/:(J)lmrll
tI!~ ............................ , ... ~iffliffil'li

Alist of Recent Indo-Western Pacific glycymeridids, with description of a new species
from Miyako Island, south Kyushu ....... .
· .. .. .. .. .. .. .. .. .. .. .. ... MATSUKUMA, A.
Notes on the ecology of the sand snail
Umbonium (Suchium) moniliferum (LAMARCK)............ OZAWA, T. and SHI:I;IOYAMA, S.
Deep burrowing mollusks .!:: shallow burrowing mollusks (J))I~.6Ht;::f*ff~nQti1:.¥.o~1¥.J~!fSl- ..•..•.••.••..•.••....•••....• l'UJIE-

Turritellid Dimorphism .......... KOTAKA, T.
Taxonomic relation of Turritella karatsuensis
NAGAO and T. infralirata NAGAO ......... .
................................ SHUTO, T.
S~e7~~~~}~(J)ID/:(J).M.:/it(J)M • .!::~(J)7t~~l¥.Jm •.......... , .WHfIl-•• IJ\~1iB~:>I"-.7-.} '7 9 7~tgg¥$$!1'l';~~4WJt:p(J)7~~~1} t;::'?\,,-C .......................... tl*~1!~
An interesting mode of occurrence of Polyptychoceras (Cretaceous heteromorph ammonoid)........ MATSUMOTO, T. and NlHONGI, M.

• ~~~W~.~(J)* • .7-.}p~~~§~~~~'?\,,-C .............................. :wJjm"f-fPermian bryozoans from the Abadeh region,
central Iran .................. SAKAGAlVU, S.
::It$~ 13 il'li~~.t:p(J) ;::vt!Rft~t;::'?\,'-C ..... .

· . . . . . . . . . . . . . . . . . . . . . . . .. tJiL!: lIf:=k ° i§::Jf~

f:k~~ ~W(J) ;:: vt!R ft~t;:: .t Q~ ~*1:.~ If (7¥Ii) .•...••............... tliU:l'll:=k ° f~*;j"IIBill.

Carboniferous ostracodes from the lower partof the Ichinotani Formation, Fukuji, Hida
Massif, central Japan .......... , .......... .
.................. ADACHI, S. and IGo, Hy.
ft~ 7 ~ 'Y ;f. (J) Balanus amaraquaticus n. sp.

.!:: ~(J)f!!!7tftt;::'?\,'-C ................ UJPNZStratigraphical distribution of ichnofossils in

the Miocene Ashiya group ............... .
· ............. SHIRAISHI, S. and SHUTO, T.
Description of ichnofossils of the Miocene
Ashiya group, II ......................... .
.............. SHUTO, T. and SHIRAISHI, S.
An Upper Permian helicoprionid fish from
Toyoma Formation, Kitakami Mountains,
Japan ..................................... .
. ... UYENO, T., MORI, K. and TAZAWA, J.

:/itW ~ .::. A.~(J);l'l;(J)~(J)fI~ft~~'Jl ......... .
.................................. I/UJW:/itZJ!;/J
Some Peridinium cysts from the Pleistocene
around Lake Hamana and its Recent bottom
sediments .. MATSUOKA, K. and FUKUYo, Y.

13 *wrd:l¥J:$~1:.:W-t:p(J)i'flIJ.=€~ft~-~(J) 2 °~~~- ....................... · .. ·.tll/UJ~1C
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Diatom correlation of DSDP, Legs 1:6 and 57
with onshore sequence in the northeast
Japan ..................................... .
KOIZUMI, I., BARRON, J. and HARPER, H. Jr.
~tWm:~~=:*i1E "Denticula hustedtii" SIMONSEN et KANA YA (J)7t~~I¥.J1l}~W: ~~ Hokkaidenticula . ...................... .I}Wf,lff.iii~ll~(J)iJf~ (~(J) 1) : ~Jilt Oitccea ....... .
. .................................. .I}Wf,lfMaestrichitian microflora of the Miyadanigawa Formation in the Hida district, Gifu
Prefecture ............................... .
· ......... TAKAHASHI, K. and SHIMOTO, H.
.;pj~.~#ft~t;:: '?\"-C (~(J) 2) ......... .
............... . UJ~Ml:=k ol/UJmi'Jlf.se. ° JlJm$'if]
Jm*m3i:llfi.(J)1JiiIJl'd~.J:$~t;::~ L. t.:M¥.oft;fit;::'?\"-C .............................. ~fii!i~~
Cuticular study on a cycad from the Palaeogene Noda Group, Northeast Japan ....... .
. ............. KIMURA, T. and HORIUCHI, J.
A note on the peculiar mode of occurrenceof foraminifers in the bottom sediments ofthe bay-head area, Kagoshima Bay ....... .
................ OKI, K. and HAYASAKA. S.
t&~3tn=.::L't.- 91!!f~~:fL!Rft~t;::'?\,'-C ~m=:1!~

Miocene foramifera from the basement rocksof Zao Volcano .. YOSHIDA, S. and SAITO, T.
n.~!i~:fL!Rt;::.t Q "7IMl7lcJ\1l" (J)~& ......... .

· ........................ ·i!i\:*~T • ± 1Ii13 *~ Quasifususulina longissima (MOLLER)

47,.;:: '0 \, , -c ............................ l!tU1:M::il!i:7J:r 91'~l1!i'€lll;6, I?.i£:-:t 7.> Pseudoschwagerina :f!i .................................. I£EE~iif
Upper Permian microfossils from the Ishiya,
ma Limestone, Gifu Prefecture ........... .
................ IGo, HH. and TAKASAKI, K.

f)ctl'il' JR:~t:'€lIlI;:: 7j-W-:t 7.> f)ctl'::fi )jI(:€i"~~~1:.~ Ff~1¥.1?Vf~ ............................ ftzJll'f!r !13
rq,1lIK~*'€lIl~~.i£: Waagenophyllum 1;::'0\"-C ..
.......................... lfl!JllJiU~ '::fi~ ~Additional notes on Late Paleozoic corals
found in the Maizuru zone, Southwest Japan............ YAMAGIWA, N. and SUZUKI, S.
i&iIJJiUlj;ffiJt;1:.~{t:::fi::z V?"/!I :/1;::'0\',-C-1.V~::fi)jl(:€i".i£:I±l~}jIOfIiJI:}.; J: ry~:fL!iHt:::fi ......... .

................ JlI~~;Jc. t~EEmt~· ~i1f;~m­
Ontogeny of epithecal and septal structuresin fossil and recent solitary scleractiniancorals .......... MORI, K. and MINOURA, K.
Soft corals ~:il!i:€i"1:.!/JJ.J C L -C~&:i!!JJ ......... .

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aeontolgical Society of Japan~qXO)~ I) i.J~;l;I) "i L t,::,O)"(":J:obLJL -CITlE L "i-to~~f*·m~f*

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Nishinomiya Kaisei Hospital, 1-4, Ohama·cho, Nishinomiya (662) "Z-;g1l'~~O)lJH<:.tm
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OIWAI, Takehiko(:'fi;J:j:~~),TSUDA, Karyu(ltEEl5MiO O)jjIjj;gi<:.t4f7JIj~~o)"-!l (*) "Z-":l
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Transactions and Proceedings of the PalaeontologicalSociety of Japan

April 30, 1979

New Series No. 113

CONTENTS
TRANSACTIONS
698.

KIMURA, Tatsuaki and HORIUCHI, junji : Some Late Early Cretaceous Plantsfrom Fukui Prefecture, in the Inner Zone of j apan.. .. . . ............

699. NAKAZAWA, Keiji, KUMON, Fujio and KIMURA Katsumi:

1

Occurrence ofCretaceous Shallow-sea Bivalves from the Northern Border of Shimanto
Terrain, Kii Peninsula, Southwest japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
700.

MATSUMOTO, Tatsuro:

15

Notes on L ewesicems and Nowall ites (Pachydiscid

Ammonites) from the Cretaceous of Hokkaido . .. . .... . . . .. . ...... ....

30

PROCEEDINGS .... .... .... . . .. ................. ... .. .. .. ..... . ...... .... .. ....

45