Transactions and Proceedingsof thePalaeontological Society of Japan
New Series

No. 79Palaeontological Society of Japan
September 31, 1970

Editor: Tokio SHIKAMA
Associate Editor: Kiyotaka CHINZEI

Officers for 1969-1970
President:

Fuyuji TAKA!

Councillors (*Executives):

Kiyoshi ASANO*, Tetsuro HANAI* (Secretary), Kotara

HATAI, Itaru HAYAMI, Koichiro ICHIKAWA, Taro KANAYA, Kametoshi KANMERA, Teiichi KOBAYASHI, Kenji KONISHI, Tamio KOTAKA, Tatsuro MATSUMOTO*, Masao MINATO, Hiroshi OZAKI* (Treasurer), Tokio SHIKAMA*, Fuyuji
TAKA!*
Executive Committee (Chairman:
General Affairs:
Membership:

Fuyuji TAKA!)

Tetsuro HANAI, Takashi HAMADA, Yasuhide IwASAKI

Takashi HAMADA

Finance:

Hiroshi OzAKI, Saburo KANNO

Planning:

Hiroshi OZAKI, Hiroshi UJIIE

Publications
Transactions:

Tokio SHIKAMA, Kiyotaka CHINZEISpecial Papers: Tatsuro MATSUMOTO, Tomowo OZAWA" Fossils":

Kiyoshi ASANO, Yokichi TAKA YANAGI

Fossils on the cover is Globorotalia truncatulinoides (D'0RBIGNY, 1839).
The photograph was taken on a scanning electron microscope, JEOL-JSM-2, x 100.

All communications relating to this journal should be addressed to the
PALAEONTOLOGICAL SOCIETY OF JAPAN
Geological Institute, Faculty of Science, University of Tokyo, Tokyo 113, japan
Sole agent: University of Tokyo Press

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 79, pp. 291-315, pis. 32-34, Sept. 30, 1970

568.

A REVIEW OF SOME CRETACEOUS CORBICULIDSIN NORTH AMERICA*YOSHIHISA OHT A
Department of Earth Science, Fukuoka University of Education~t;l!<:<Vs.!Ili~:/ :/ ~ n·~:: !Jifi<V~J(fli!K.'"?v'"C<V:p'i=~{;-f: Colorado *'!f:<V Henderson Museum IC}'J:, Me HENDERSON ~t~cj)%:1J~~~C.t -?"CJ*~, 7i}fJE~tJ,f.:S:i!E~:/:/ ~ n·~::m<Vi"" I'! I? L- H)l'{:;f>:iJ;~ <f*~~ h-cv<~>o {-hi? <Vt)l'{:;;t;:<V$ 1:, i!il::ff<V .tv' 12 fli!IC '"?v'"Cift~~t L-t.::_f.tf*, f/t*~Jt/£~ h"Cv't.:!IE~ Leptesthes, Veloritina :tt:M5E~ L.., ~./i'~ Bendersana ~IT!Hr, 3/m9fiJlh::.~l''!!L-t.:o '*-f.::/:1~ :tli::~Jic:t1<1-¥"t.Qjji}ffll! Geloina? rodecki ~~-L-~o'*-~•{-tJ,~tJ,Q)~~~~-·-~ft~~_t~,~-7~~T.t5~~-~-~

HA t?il>IC l.-, ~t;lj~J][<V "b <Vf'J:ffu<V*F>i<V "b IV UM~M:il;j;-lt' (::. c ~<V.....::t.:ot;. 133 g. !Astudies on the related districts werecarried on along with their economic
significance by many geologists andpaleontologists (BOWEN, 1915, CALVERT,BEEKLY, BARNETT and PISHEL, 1914,
HENDERSON, 1907, 1910, 1920, 1935, LEE,
1912, REESIDE, 1924, STANTON, 1916, 1920,
STANTON and KNOWLTON, 1897, STANTON
and HATCHER, 1905, VEATCH, 1907), andthe stratigraphical sequences and correlation of the Cretaceous in North
America were founded by them. The
paleontological study of the Corbiculidae
was excellently made by HENDERSON(1907, 1910, 1935) but there have beenfew subsequent works.
There are many well-preserved specimens of Corbiculidae in the Universityof Colorado Museum which were collected by the late Professor Junius HENDERSON and by many students. In thispaper, I describe the following ten species which are based on particularly
well-preserved specimens.

I. Introduction and Acknowledgements
As already known, the original representative of the Corbiculidae can betraced to the Upper Jurassic, and thefamily in Mesozoic flourished in theUpper Cretaceous, in contrast to the
Neomiodontidae, which flourished in theLower Cretaceous. The prosperity of
the Corbiculidae in the Upper Cretaceous
is well manifested in the Laramie formation. The representatives of theCretaceous Corbiculidae in North America were mainly studied by MEEK and
HAYDEN (1856, 1860a, b, c), MEEK (1869,
1870a, b, 1872, 1875, 1876, 1877) and
WHITE (1878a, b, 1879a, b, 1882, 1883a, b,
1891, 1895). Although more than twenty
species were described by their authors
from the Cretaceous formations, thestratigraphical relationship of the species was not clear at that time. Entering this century, the stratigraphical

Hendersona subelliptica (MEEK and HAYDEN), new genus* Received December 23, 1969; read November 29, 1969, at Kagoshima.
291

292

Yoshihisa OHTA

Hendersona umbonella (MEEK) [ =Corbicula obesa WHITE]
Hendersona cardiniaeformis (WHITE)
Leptesthes fracta (MEEK)
Leptesthes berthoudi (WHITE)
Leptesthes augheyi (WHITE)
Veloritina derkeei (MEEK)
Veloritina cleburni (WHITE)
V eloritina occidental is (MEEK and HAYDEN) [ =Corbicula cytheriformis MEEK
and HAYDEN]
Geloina (?) rodecki OHTA, new species

At this point, I wish to express mysincere thanks to Prof. Hugo G. RoDECK,
Director of the University of Colorado
Museum, and Dr. Peter ROBINSON, Curator of Geology in the Museum, forthe privilege of studying the many wellpreserved specimens which are kept in
the Museum. My thanks go to Prof.
Bruce F. CURTIS, Chairman of the Department of Geological Sciences, andalso to Dr. Erle G. KAUFFMAN, Associate Curator of the Division of Invertebrate Paleontology of the U.S. National
Museum, for the privilege of studying
the type collection of Mesozoic Corbiculidae. Thanks are due to Dr. ROBINSON
and Mrs. Kirk NEVIN for their invaluable advice and critical reading of themanuscript, and Mr. Tom ZEILER for
his assistance in photography.
Thanks are also due to Prof. Tatsuro
MATSUMOTO of the University of Kyushu for his invaluable advice and critical reading of the manuscript, and to
Emeritus Prof. Teiichi KOBAYASHI of
the University of Tokyo; the late President Toshio KuMURA and friends ofthe Department of Science of the Fukuoka University of Education for theirinvaluable advice and assistance.
This study was supported by the governmental all-expense travelling fundfrom the Ministry of Education in Japan.

II.

Terms used in this paper(A) Size of shelL-Generally the following terms are used : small, medium
and large. However, these terms are
subjective in many cases. Therefore I
shall use the following five grades : (1)very small (< 10 mm), (2) small (10 mm30 mm), (3) medium (31 mm-50 mm), (4)large (51 mm-70 mm), (5) very large (>70 mm). Of course, this standard should
be used only for the Corbiculidae, inwhich case size always refers to thelength (L) of shell.
(B) Inflation of shelL-In this paper the
inflation of shell is represented by theratio of W (t thickness of shell) to height(H), and the following three grades areused: (1) small (0.3-), (2) medium (0.30.5), (3) large (0.5+).
(C) Sinupalliated nature:a-type: non-sinuated or with a slight
curve near the posterior adductor.
b-type: abruptly and nearly verticallybent from the ventral line with a slight
curve near the posterior adductor.
c-type: a fairly deep, rounded sinus, but
forming less than a semicircle.
d-type: deep and subtrigonal sinus.

···b-typeText-fig. 1. The types of sinuationin the Corbiculidae.

In the taxonomy of the Corbiculidae,
the nature of pallial sinus went unnoticed until recently. TRYON and STANTON(1893, p. 103) found differences among

568.

Cretaceous Corbiculids in North America

the pallial sinuses in the remains offossils in the Upper Cretaceous, but they
did not use these differences as standards of classification of the Corbiculidae.
Of course, the nature of the pallial sinus
is related to an ecological condition tosome extent, and therefore I have tried
to classify the Corbiculidae with regard
to their sinupalliated nature as well as
their other characteristics.

III. Systematic description
Family Corbiculidae
Genus Hendersona OHTA, nov.
Type-species.-Tell ina subelliptica MEEK
and HAYDEN, 1856, Lance formation (Upper Cretaceous), South Dakota.
Diagnosis.-Shell of small to large size,
equivalve, inequilateral, suboval to subelliptical; beak small, not much elevated,prosogyrous, anterior to midpoint ; posterior carinae absent or very weak ;without escutcheon and lunule; surface
usual and some imbrications of growth ;pallial line abruptly curved from theventral-line and bent near the posterior
adductor scar (b-type) ; adductor scars
strongly impressed; hinge cyrenoid, dentition as formulated :Alii AI
All

3a

1 3b
2a 2b 4b

PI

Pili
PII

cardinals diverging from beak with weakgrooves; laterals long, transverse crenulations, posterior laterals very remotefrom cardinals, but nearly as long as
anterior laterals.
Remarks.-The characteristics of thisgenus are the b-type sinupalliated nature
and a subelliptical to subovate outlineof the shell. MEEK (1876) ascribed subelliptica to the group of Corbicula (Leptesthes) fracta, the type of subgenus.

293

In fact, Corbicula (Leptesthes) subelliptica
is similar to C. (L.) fracta in the outlineof shell and hinge structure, but differsfrom the latter in the b-type sinupalliated nature. The sinupalliated natureof this genus is more similar to that ofLeptesthes and V eloritina than that of
Eocallista, Tetoria, Fulpia, Dentonia andCorbicula, but differs from them in the
degree of sinuation. On the basis of
the differences in pallial sinus, I propose
this new genus. The species of thisgenus flourished mostly in the Laramie
formation and numerous specimens werecollected by Prof. Junius HENDERSON etal. from many localities in North America. It is named in honor of the lateProf. Junius HENDERSON, who madevaluable contributions to the knowledgeof the Mesozoic Corbiculidae of North
America.
Hendersona subellipitca(MEEK and HAYDEN)
Pl. 32, figs. 1-9; text-fig. 21856. Tellina subelliptica, MEEK and HAYDEN,
Phi. Acad. Nat. Sci., Pr., 8, p. 83.
1876. Corbicula (Leptesthes) subelliptica,
MEEK, Rept. U.S. Geol. Surv., Terr.,
9, p. 523, pl. 43, fig. 9.
1878. Corbicula (Leptesthes) subelliptica,
WHITE, 12th Ann. Rept., pt. 1, p. 79.
1883. Corbicula (Leptesthes) subelliptica,
WI-liTE, 3rd Ann. Rept. U.S. Geol.
Surv., p. 437, pl. 20, figs. 10, 11.
1905. Corbicula (Leptesthes) subelliptica,
ScHUCHERT, U.S. Nat. Mus., Bull. 53,
pl. 1, p. 167.
1914. Corbicula subelliptica, CALVERT, BEEKLY, BARNETT and PISHEL, U.S. Geol.
Surv., Bull. 575, p. 20.
1920. Corbicula subelliptica, HENDERSON, Colo.
Geol. Surv., Bull. 19, p. 43, 49.

Material.-Holotype: USGS 441, rightvalve, from loc. Cherry Creek, SouthL

Yoshihisa OHTA

294

Dakota (MEEK Coli.) ; Plesiotype : USGS
8123, right valve, from loc. Bijo·u Creek,
Colorado (WHITE Coli.). Henderson Museum: No. 12664 (Pl. 32, Figs.T-7), left
and right valves, from loc; · NW of
Briggsdale, Colorado (J. HENDERSON and
E. G. SMITH Coli.); No. 12633 (Pl. 32,
Figs. 8, 9), right valve and right internalmould, from loc. 2 miles S. of Cornish,
Weld Co., Colorado (J. HENDERSON and
E.G. SMITH Coli.).
Description.-Shell small-sized for the
genus, ovate to subelliptical in outline,
longer than high, and the inflation ofshell stnall ; test thin ; beak small, notmuch elevated, prosogyrous, placed alittle in advance of the center; anterodorsal margin slightly concave in frontof umbo, smoothly sloping down into
the anterior margin; postero-dorsal margin gently convex, longer than the anterior dorsal one; posterior margin fairly
long and truncated or rounded; ventral
margin gently arched; posterior carination absent or very weak ; surface ornamented with fine growth-lines and someprominent concentric ribs; ligament external ; hinge cyrenoid ; cardinal teeth
stout with grooves, radiating from thebeak; 3a small, opisthocline, represented
by the terminal thickening of Alii ; 1
stout with groove, orthocline; 3b stout,
prosocline; 2a fairly stout, opithocline,
remote from All; 2b stout with groove,a little prosocline; 4b elongate but notstrong, very prosocline ; lateral teeth
elongated along the antero- and posterodorsal margins, apparently cross-striated; antero-laterals about same as
postero-ones in length; nymph comparatively wide, adductor scars strongly
impressed, fairly large, placed near theboth ends of the lateral teeth; pallial
line sinuated, but shallow, somewhat
abruptly and vertically with the ventral
line, bent upward and curved near posterior adductor scar (b-type) ; pedal scar
not clearly impressed.
Observation and comparison.-A large
number of well-preserved specimens exhibiting the internal and external characters are kept in the University ofColorado Museum, and these can certainly be referred to Hendersona subelliptica.
The ratio of height to length is comparatively constant, ranging from about
0.8 to 0.7. The inflation of shell issomewhat variable between the younger

Measurements in mm.Specimen
12664 (bivalve)(right valve)(left valve)(right valve)(bivalve)12633 (bivalve)
(

)

(

)

(

)

(

)

USGS 441 (right valve)8123 ()

LengthHeightW C-k thickness)

H/L

W;H

17.0
18.5
19.0
17.5
16.0
22.0
26.0
19.0
23.0
21.0
11.5
20.0

14.0
14.0
15.0
13.5
12.0
15.0
19.0
13.0
16.0
15.0
8.0
16.0

5.0
4.0

0.8
0.8
0.8
0. 77
0. 75
0.68
0. 73
0.68
0.69
0. 71
0.69
0.80

0.35
0.30

4.0
4.0
5.0
5.3
4.0
5.0
4.0
4.0

0.30
0.33
0.33
0.27
0.30
0.31
0.26
- (holotype)
0.25

568.

Cretaceous Corbiculids in North America

and adult specimens, ranging from about
D.35 to 0.25. The variation of outline ofshell is a fairly wide range from ovate
to subelliptical as shown in text-fig. 2.
In the younger stage it exhibits a subelliptical outline, but in the adult stage
the forms are varied from subellipticalto subovate. The characteristics of thisspecies are generally small size, medium
inflation and subelliptical outline of shell.

Text-fig. 2. The variation of outline
of Hendersona subelliptica.

In the outline of shell this species is·somewhat similar to C. fracta and C.
.cardiniaeformis, although the size of shellis very different from the latter two:species. Similar size and outline of shell.appear in Corbicula macropistha WHITE
from the Laramie formation. WHITE{1878, p. 78) pointed out that the specific·character of C. (Leptesthes) macropistha{Syntypes, USGS 8124, 12475, WHITE·Coli.) is the peculiar flattening of theumbonal and upper middle portion of
the shell. This characteristic, however,is not clear in all specimens which are
named as C. (L.) macropistha by HENDERSON (No. 12633, Pl. 32, Figs. 8, 9).
Also the outline and the inflation of·shell are included in the variation range·Of H. subelliptica, and furthermore both
·species often coexist with each other inthe same beds. Therefore, the specimen
which are named as C. (L.) macropistha
by HENDERSON are not related to macropistha, but closely related to H. subelliptica.

295

Occurrence.- The Laramie formationof northern Colorado and Lance formation of South Dakota and Montana.
Hendersona umbonella (MEEK)
Pl. 32, figs. 10-18; text-fig. 31875. Corbicula umbonella MEEK, Hayden
Surv., Bull. 2nd ser., no. 1, p. 44.
1878. Corbicula obesa, WHITE, Bull. U.S.
Geol. and Geogr., Terr., Art. 28, no.
6, p. 712.
1878. Corbicula obesa WHITE, 12th Ann.
Rept., pt. 1, p. 72, pl. 23, figs. 3a-e.
1883. Corbicula umbonella WHITE, 3rd Ann.
Rept. U.S. Geol. Surv., p. 438, pl. 21,
figs. 7-10.
1883. Corbicula obesa, WHITE, 3rd Ann.
Rept. U.S. Geol. Surv., p. 437, pl. 23,
figs. 7-11.
1903. Corbicula (Cyanocyclas) umbonella,
DALL, Wagner Free lnst., Tr., 3, pt.
6, p. 1451.
1903. Corbicula (Cyanocyclas) obesa, DALL,
Ibid, p. 145.
1920. Corbicula umbonella, HENDERSON, Colo.
Geol. Surv., Bull. 19, p. 43 ..

MateriaL-USGS 12468 (Plesiotype),from Joe. 15 miles north of Orchard
station, Colorado (WHITE Coli.) ; USGS
9025 (Syntypes), from Joe. Crow and
Bijau Creeks, northern Colorado (WHITE
Coli.). Henderson Museum, No. 13550(Pl. 32, Figs. 10, 11), left and right valves,from Joe. R. 61 W. south of Cornish, Colorado (HENDERSON and SMITH Coil.) ;No. 12764 (Pl. 32, Figs. 13, 17, 18), bivalve, from Joe. east of Osgood, Colorado(HENDERSON and SMITH Coli.) ; No. 12700(Pl. 32, Figs. 15, 16), left and right valves,from Joe. SE of Fosston, Colorado; No.
7782 (Pl. 32, Fig. 14), left valve, fromJoe. NW of Morgan, Colorado (HENDERSON and SMITH Coli.).
Description.-Shell of medium size,
moderately inflated; sides somewhat

Yoshihisa OHTA

296

regularly convex, inequilateral, suboval
or subtrihedral in marginal outline;transverse length somewhat greaterthan the height; beaks small, not prominent, prosogyrous, and placed at a thirdof shell length from front; without
lunule; antero-dorsal margin slightly
concave in front of umbo, meeting withregularly rounded anterior margin;
ventral margin broadly convex; posterior margin regularly rounded or somewhat truncated ; postero-dorsal margin
a little convex; posterior carination
absent or very weak. Surface marked
only by fine growth-lines and imbrications of growth and with two or threeirregular radiating rugae on the posterior area. Hinge teeth strong; cardia!
teeth stout with grooves, radiating fromthe beak; 3a very small, opisthocline,
represented by the terminal thickeningof Alii; 1 stout with groove, more orless prosocline ; 4b elongate but thin,very prosocline; lateral teeth elongate,strong and finely crenulated, the lengthof anterior laterals subequal to posterior
ones; anterior laterals more or lesscurved near adductor scar ; posterior
laterals remote from the cardinals, elongate and nearly straight; nymph comparatively wide, fairly regular fine nods
on the surface; adductor scars strongly
impressed, fairly large; pallial line sinuated, curved near posterior adductor
scar (b-type) ; pedal scar not clearly

impressed.
Observation and comparison.- When C
obesa is compared with H. umbonella,
one cannot distinguish a difference between them in the sinupalliated nature,outline, size, inflation or surface ornamentation of shell. WHITE (1882, p. 439)
said, "Shell resembling Corbicula obesa
WHITE, in most respects, but it is proportionally longer, the umbones are·fuller and more elevated, and upon theposterior portion there are upon eachvalve two or three indistinct radiating:rugae. Upon other parts the surface ismore than usually smooth." Having
examined a great many well-preserved
specimens from the type locality of C.
obesa and the holotype and paratype
specimens (USGS 12468, 9025), I havefound that the above differences between H. umbonella and C. obesa pointed out by WHITE are very doubtful.
As illustrated in text-fig. 3, the younger

Text-fig. 3. The variation of outline
of Hendersona umbonella.

forms of C. obesa are suboval or subtrihedral and their umbones are notprominent, but their umbones graduallyA1easurements in mm.Specimen
13550 (left valve)
12700 (right valve)(left valve)
12764 (bivalve)13550 (right valve)
12700 (right valve)i

LengthHeightW (~ thickness)

H/L

WjH

1-

36.0
30.5

30.0
26.0
22.0
27.0
27.0
24.0

13.0
12.0
8.0
10.0
11.0
9.0

0.83
0.85

0.43
0.46
0.36
0.37
0.41
0.38

I

34.0
31.0
27.0

0. 78
0.87
0.89

568.

Cretaceous Corbiculids in North America

protrude with growth. Two or threeindistinct radiating rugae can be seen
upon the posterior portion of C. obesa
in general, and particularly upon thespecimens which have the posteriorcarinations. Therefore I think C. obesa
is synonymous with H. umbonella. Some
trancated forms of H. umbonella arevery similar to C. augheyi, but thisspecies differs from the latter in thesinupalliated nature. I believe that thedifferences between them depend upon
their ecological differences. Some younger forms of H. umbonella are also quite
similar to some younger ones of H.
cardiniaeformis in the outline of shelland the pallial sinus, but their adultforms can be distinguished from eachother by their size and their surface
ornamentation. As may be determinedfrom their occurrences and ontogenetical
relationship, they are closely related toeach other, and perhaps H. cardiniaeformis derived from H. umbonella.
Occurrences.- The Laramie formationof northeastern Colorado.

Hendersona cardiniaeformis (WHITE)
Pl. 32, figs. 19-27; text-fig. 4
1878. Corbicula cardiniaeformis WHITE, 12th
Ann. Rept. U.S. Geol. Surv., Terr., pt.
1, p. 73, pl. 25, figs. Sa, b.
1878. Corbicula cardiniaeformis, WHITE, Bull.
U.S. Geol. Geogr. Surv., Terr., vol. 4,
no. 3, p. 711.
1883. Corbicula (Leptesthes) cardiniaeformis,

3rd Ann. Rept. U.S. Geol.
Surv., p. 437, pl. 22, figs. 10-15.
1903. Corbicula (Leptesthes) cardiniaeformis,
DALL, Wagner Free Inst., Tr., 3, pt.
WHITE,

6, p. 1447.
1907. Corbicula cardiniaeformis, HENDERSON,
Univ. Colo. Stud., 4, p. 152.
1920. Corbicula cardiniaeformis, HENDERSON,
Colo. Geol. Surv., Bull. 19, p. 43, 44,
47.

297

Material.-Ho!otype, USGS 9024, bivalve, from Joe. Crow Creek, northern
Colorado (WHITE Coli.). Henderson Museum No. 5255, left valves (Pl. 32, Figs.
19, 22), from Joe. SE of Cornish, Colorado; No. 13549, 13262, left valves (Pl.
32, Figs. 20, 21), from Joe. E. of Cornish,
Colorado; No. 12772, left valve (Pl. 32,
Fig. 23), from loc. E. of Osgood, Colorado; No. 5221, left valve (Pl. 32, Fig.
26), from Joe. NE of Osgood, Colorado,near type locality (J. HENDERSON and
E. G. SMITH Coli.) ; No. 2041, left andright internal moulds (Pl. 32, Figs. 24,
25, 27), from Joe. Crow Creek Dam, 25
miles NE of Greeley, Colorado (J. HENDERSON and H. W. CLATWORTHY).
Description.-Shell of large size; inflation of shell medium to large; inequilateral, subelliptical in marginal outline;transverse length greater than theheight; beaks small, not prominent,
prosogyrous, and placed about a thirdof shell length from the front; without
lunule ; antero-dorsal margin slightly
concave in front of umbo, elongate, andmeeting with a more or less narrow,regularly rounded anterior margin ;ventral margin broadly rounded ; posterior margin regularly rounded orsom,ewhat truncated;postero-dorsal
margin elongated, nearly straight orslightly convex; posterior carinations
from beaks to posterior margin weak
but distinct. Surface ornamented withfine concentric growth-lines and some
imbrications of growth, sometimes H.
umbonella-like irregular radiating rugaeon the posterior area. Hinge teeth comparatively strong ; cardinal teeth stout
with groove, radiating from the beak;3a small, opisthocline and connect with
Alii, 1 stout with groove, prosocline;
3b stout, very prosocline ; indistinct development of· AO and PO-like teeth on
the left valve ; lateral teeth elongated,Yoshihisa OHTA

298
Measurements in mm.Specimen

LengthHeightW Ci thickness)

H/L

W/H

13549 (left valve)
13262 ()
13553 (right valve)
2041 ()
5255 (bivalve)

37.0
40.0
32.0
51.0
35.0

29.0
28.0
25.0
40.0
27.0

10.0
11.0
10.5
14.0
10.0

0.78
0. 70
0.78
0. 78
0. 77

0.34
0.39
0.42
0.35
0.37

finely crenulated ; anterior laterals about
equal to posterior ones in length; adductors subequal and strong; pallial
sinus b·type.
Observation and comparison.-! observed many well-preserved specimens
which have been collected from themany localities of northern Colorado
including the type locality. This species has a fairly wide range of variation in the outline of shell. As shownin text-fig. 4, some younger forms are

fracta for the following reasons: (a)The younger forms of this species are
similar to H. umbonella. (b) This species is the same as H. umbonella in thesinupalliated nature and differs fromthat of C. jracta. This species is alsosimilar to C. planumbona in the outlineof shell, but the ratio of height to lengthof this species is smaller than that ofplanumbona. I did not observe any
well-preserved specimens of C. planumbona, and therefore I can not draw any
conclusions concerning the relationshipbetween the two species.
Occurrence.- The Laramie formationof northeastern Colorado.

Genus Leptesthes MEEK, 1870

Text-fig. 4. The variation of outline
of Hendersona cardiniaeformis.

very similar to H. umbonella in outline,
posterior carination and pallial sinus.
The adult forms, however, can easily
be distinguished from H. umbonella bytheir outline and large size. As alreadypointed out by WHITE (1878, p. 73), theadult forms of this species are surely
similar to C. jracta in the outline ofshell. He considered this species avariation of fracta. However, I am ofthe opinion that this species is moreclosely related to H. umbonella than C.

Type-species.-Cyrena (Corbicula ?)jracta MEEK, 1870, Upper Cretaceous,
Wyoming (original designation).
Diagnosis (emended).-Shell of large
size, equivalve, inequilateral, longitudinally subelliptical or subovate, posterior
margin narrower than the other, andsubtruncated. Umbo not prominent,
beak rather depressed, prosogyrous, anterior to mid-point;.· surface only showing very obscure lines and somewhat
stronger imbrications of growth; pallial
line shows a fairly deep, rounded sinus
but forming less than a semicircle (ctype) ; escutcheon and lunule absent ;adductor scars strongly impressed; hinge
cyrenoid ; cardinal teeth stout but neither

568.

Cretaceous Corbiculids in North America

bifid nor grooved, radiating from thebeak; 3a comparatively well developed;
lateral very long, finely and transversely
crenulated; posterior laterals very remote from the cardinals, but about thesame as anterior ones in length.
Remarks.-MEEK (1870) established
Leptesthes as a subgenus of Cyrena
based on Cyrena fracta MEEK from theLaramie formation for the reason that
Leptesthes has some characteristics ofboth Cyrena and Corbicula without agreeing exactly with either. That is, theanterior laterals of Leptesthes are similar to those of Corbicula in their elongation and fine-crenulation, but the posterior laterals of this subgenus agreewith those of Cyrena, being shorter andmore remote from the cardinal teeth
than in Corbicula. Cyrena LAMARCK(1818) is synonymous with Corbicula
MEGERLE (1811), Corbicula, V eloritina,
Leptesthes and the other genera ofCorbiculidae have generally fine crenulation on their lateral teeth and also
indistinguishable difference between thelength of the anterior and posterior
laterals. However, there are some differences among their degrees of remoteness from the cardinals, but not many
·difference among the length of theirlaterals. Therefore, the subgeneric characteristics of Leptesthes become obscure.
I emended the definition of Leptesthes
in the following way to rank it as agenus; the longitudinally subelliptical·Or subovate outline of shell and the ctype sinupalliated nature are the characteristics of this genus. The longitudinally subelliptical form is very common
in some genera of Unionidae but its
form is unique in the Corbiculidae. Hen.dersona subelliptica from the Laramie
formation of North America has asomewhat similar form, but differs fromthis genus in its sinupalliated nature.

299

In its sinupalliated nature, this genus issimilar to Veloritina but easily distinguishable from the latter by having nolunule, and a different outline of shell.
Leptesthes fracta (MEEK)
Pl. 33, figs. 1-6; text-fig. 51870. Cyrena (Corbicula ?) fracta MEEK, U.S.
Geol. Surv., 4th Ann. Rept., Terr., p.
298.
1878. Corbicula (Leptesthes) fracta, WHITE,
U.S. Geol. Surv., 12th Ann. Rept.,
Terr., pt. 1, p. 75-77, pl. 21, fig. 5.
1883. Corbicula (Leptesthes) fracta, WHITE,
U.S. Geol. Surv., 3rd Ann. Rept., p.
439, pl. 20, figs. 2-6.
1897. Corbicula fracta, STANTON and KNOWLTON, Bull. Geol. Soc. Am., vol. 8, p.
144.
1907. Corbicula fracta, HEKDERSON, Univ.
Colo. Stud., 4, p. 152.
1912. Corbicula fracta, LEE, Bull. U.S. Geol.
Surv., vol. 510, p. 7-219, pis. 79-83.

Material.-USGS 7742 (Syntype), fromJoe. Hallville Coal Mines, Wyoming(MEEK Coil.) ; USGS 8104 (Plesiotypes),from Joe. Black Butte Station, Wyoming(WHITE Coil.). Henderson Museum No.
10523, right valves, left and right internal moulds (Pl. 33, Figs. 1-4), from Joe.
Black Buttes, Wyoming; No. 10485, leftinternal mould (Pl. 33, Fig. 5), from Joe.
6 miles E. of Point of Rock, Wyoming;
No. 17859, left internal mould (Pl. 33,
Fig. 6), from Joe. Weld, Colorado (J.
HENDERSON and E. G. SMITH Coli.).
Description.-Shell very large size;
longitudinally subelliptical or subovate
in outline, much longer than high; theinflation of shell small ; test thick; beaksmall, not much elevated, prosogyrous,
placed about a third of shell length fromthe front; no lunule; antero-dorsal margin slightly concave in front of umbo;
anterior margin rounded ; ventral mar-

Yoshihisa OHTA

300

Measurements in mm.Specimen

LengthHeightW (! thickness)

H/L

w;H

10523 (bivalve)(right valve)(bivalve)10835 ()
17859 ()
10485 (
)

74.0
59.0
54.0
44.0
34.0
44.0

44.0
38.0
34.0
25.0
23.0
21.0

10.0
10.0
10.0
7.0
7.0
6.0

0.59
0.64
0.63
0.57
0.68
0.48

0.23
0.26
0.29
0.28
0.30
0.29

gin broadly arched ; posterior margin
narrower than the other, and subtruncated ; dorsal margin sloping graduallywith slight convexity; posterior carination indistinct. Surface marked withfine concentric growth-lines and some
imbrication of growth. Hinge teeth
comparatively strong; cardinal teeth
stout but neither bifid nor grooved,radiating from the beak; 3a small but
distinctly developed, opisthocline, represented by the terminal thickening of
Alii ; 1 stout; acline ; 3b stout andstrongest in the cardinals, very prosocline, laterals elongated along the anteroand postero-dorsal margins ; apparently

cross-striated ; linear posterior lateral
teeth very remote from the cardinals
but they are the same as the anterior
ones in length; adductor scars strongly
impressed, fairly large, placed near theboth ends of the lateral teeth ; pallial
line shows a fairly deep, rounded sinus
but forming less than a semicircle (ctype).
Observation and comparison.-! examined many specimens from the Laramie
formation, Black Buttes, Wyoming (no.
10523) and 6 miles east of Point of Rocks,
Wyoming (no. 10485) which were collected by HENDERSON and SMITH. The position of the umbo and the ratio of

Text-fig. 5. The variation of outline of Leptesthes fracta.

568.

Cretaceous Corbiculids in North America

height to length apparently vary tosome extent (see Text-fig. 5). The specimens which have a submedian umbo
and a comparatively large ratio ofheight to length are similar to Hendersona cardiniaeformis, as already pointed
out by MEEK. He asserted that H. cardiniaeformis is probably a variety of H.
fracta. I can not agree with his opinion, however, because the sinupalliatednature of H. cardiniaeformis differs fromthat of H. fracta. The immature formsof this species also bear some resemblance to H. subelliptica in the outlineof shell, and WHITE (1878) thought thatH. subelliptica belonged to Leptesthes.
However, the sinupalliated nature of H.
subelliptica differs from that of L. fracta.
The difference in sinupalliated natures
perhaps indicates a difference in ecological conditions, and therefore H. subelliptica is not related to this species.
Corbicula crassatelliformis (MEEK) was
distinguished from L. fracta from thesame locality by MEEK (1870, p. 315) for
the reasons that it had a more trigonal
outline, more prominent post-umbonal
slopes, and proportionally stronger ridges
of growth. However, among the numerous examples of the variety of L. fracta
which were obtained from the above
localities are many specimens whichshow a direct gradation to that type ofform which cannot be separated fromL. fracta. I have treated it as synonymous with L. fracta.
Occurrence.- The Mesaverde and equivalent strata of southern Wyoming andnorthwestern Colorado, and the Laramie
formation of northeastern Colorado.
Leptesthes berthoudi (WHITE)
Pl. 33, figs. 7-11
1882. Corbicula berthoudi WHITE, Proc. U.S.
Nat. Mus., vol. 5, p. 94, pl. 4, figs. 1-3.

301

1883. Corbicula berthoudi, WHITE, 3rd AnnRept., U.S. Geol. Surv., p. 438, pl. 21,
figs. 1-3.
1907. Corbicula berthoudi, HENDERSON, UnivColo. Stud., vol. 4, p. 152.
1920. Corbicula berthoudi, STANTON, ProfPap., U.S. Geol. Surv., p. 29, figs. 1-3.

Material.-USGS 11556 (Syntype), fromloc. valley of South Platte River, Colorado (WHITE CoiL). Henderson Museum
No. 12699, left and right valves (Pl. 33,
Figs. 7, 8), from loc. SE of Fosston,Colorado; No. 17827, right valve (Pl. 33,
Fig. 11), from loc. 1.5 miles E. of Fosston,Colorado (J. HENDERSON and E. G. SMITH
Coli.).
Description.-Shell of large size, subelliptical to subtetrahedral in outline,
moderately inflated, much longer thanhigh ; test thick ; antero-dorsal margin
slightly concave in front of the umbo,
passing gradually into smoothly arched
ventral ; postero-dorsal margin gently
curved and turned at posterior marginand postero-ventral corners with obtuse
angles ; urn bo recurved, large, rising
fairly high above hinge margin, prosogyrous, situated a third of shell lengthfrom front; without lunule and escutcheon ; surface with dense concentriclines and some imbrications of growth;
adductor subelliptical and subequal toeach other and fairly large, strongly
impressed ; pallial sinus c-type ; hinge
cyrenoid; cardinals divergent from beak:
3a very small, tuberculiform, opisthocline, formed by a thickening of lateralAlii at its posterior end, defined fromit by change of orientation; 1 fairly'stout with groove, prosocline, situatedbelow beak; 3b stout, large with groove,
trigonal, very prosocline ; laterals longand fine crenulated; AI elongated, narrow and curved along the margin ofadductor; Alii long, stout but roundedat top, gently convex ; PI and Pili very

Yoshihisa OHTA

302
Measurements in mm.Specimen

LengthHeightw a thickness)

H/L

W;H

12724 (bivalve))()((rightvalve)"" (bivalve)

57.0
56.0
48.0
32.0
37.0

47.0
46.0
40.0
29.0
33.0

16.0
16.0
14.0
12.0
13.0

0.82
0.82
0.83
0.90
0.89

0.34
0.34
0.35
0.41
0.39

remote from cardinals, long, stout, gently
curved.
Observation and comparison.- The outline varies to some extent between theimmature and adult specimens, and also
among the adult specimens. The immature specimens are ovate or subelliptical in outline, and the inflation of shell
is fairly large, but the adults are subtetrahedral to subelliptical in outline, theinflation of shell is small, and the degreeof protrusion of the umbo has increased.
Among the adult specimens, the outline
is also variable in the posterior marginal outline. Among specimens whichwere collected from the same bed, thesubtetrahedral outline is truncated at
the posterior margin, whereas the subelliptical outline is rounded. When thisspecies was described by WHITE (1882),
it was the largest specimen known.
However, it may be determined frommy examination of a large sample ofspecimens which were collected by many
students from many localities, that thisis not the largest specimen in the Corbiculidae. This species resembles H. cardiniaeformis in its large size and its
outline of shell, although it is isolated
from that species with regard to theirsinupalliated natures. This species isvery similar to L. fracta in its pallial
sinus and absence of a lunule. It is
probably included in the genus Leptesthes, but is specifically distinct from thelatter in its outline and inflation of shell.

I think this species was probably derived
from some subelliptical form of L. fracta
in the Late Fox-hill or Early Laramieage, and flourished in the Laramie age.
Occurrence.- Laramie formation, valleyof South Platte River, northeastern Colorado.

Leptesthes augheyi (WHITE)
Pl. 34, figs. 3-6
1882. Corbicula augheyi WHITE, Proc. U.S.
Nat. Mus., vol. 5, p. 95, pl. 4, figs.
4-6.
1883. Corbicula augheyi, WHITE, 3rd Ann.
Rept., U.S. Geol. Surv., pl. 21, figs.
4-6.
1920. Corbicula augheyi, HENDERSON, Colo.
Geol. Surv., Bull. 19, p. 43, 47.

Material.- USGS 11557 (Syntypes), fromloc. valley of South Platte River, Colorado (WHITE CoiL). Henderson Museum
No. 12698, left and right valves (Pl. 34,
Figs. 3-6), from loc. SE of Fosston, Colorado; No. 5229, right valve, from loc.
E. of Fosston, Colorado; No. 17827, bivalve, from loc. 1.5 miles E. of Fosston,Colorado (J. HENDERSON and E. G. SMITH
Coli.).
Description.-Shell of large size, highly inequilateral, subtetrahedral, much
longer than high, moderately inflated ;test thick; antero-dorsal margin fairly
concave in front of the umbo, passing
gradually into the anterior margin;

568.

303

Cretaceons Corbicnlids in North America

lvfeasurement s m mm.Specimen

LengthHeight

W G thickness)

H/L

w;H

0. 76
0.81
0.83
0.82
0. 75

0.42
0.37
0.31
0.37
0.44

·--------

5229 (right valve)
12698 (left valve)
17827 (bivalve)
17827 ()
12698 (left valve)

43.0
43.0
56.0
58.0
36.0

33.0
35.0
47.0
48.0
29.0

ventral broadly arched; postero-dorsal
margin much longer, nearly straight,
forming an obtuse angle with the posterior margin ; posterior end truncated,the direction of the truncated marginusually a little drawn perpendicularly
with the base of the shell; umbo prosogyrous, considerably elevated above thehinge margin, placed at about one thirdof shell length from the anterior end;
lunule and escutcheon absent; two obtused ridges extending from the umbo
to the postero-dorsal angle, difining aslightly concave posterior dorsal slope;surface ornamented with the fine growthlines and some imbrication of growth;
anterior scar more or less stronger thananterior one, both ones strongly impressed; pallial sinus c-type; hinge thesame as the preceding.
Observation and comparison.- The degree of protrusion of the umbo is variable in the process of growth; in theimmature stage the degree of protrusion
is slight and similar to some truncatedforms of L. fracta and C. planumboana.
However, the degree of protrusion gradually increases with growth. The outline
in adult specimens is fairly constantamong about fifty specimens from theLaramie formation east of Fosston,Colorado. The subtetrahedral outline,
fairly distinct posterior ridges and protruded umbo are the characteristics ofthis species. I once considered L. augheyi
to be synonymous with L. berthoudi,

14.0
13.0
15.0
18.0
12.0

because the above mentioned characteristics can to some extent be seen in theadult specimens of L. berthoudi, andboth species generally coexist in thesame beds. However, I have treated it
as a valid species having a comparatively constant outline of shell as wellas the other above characteristics. This
species is probably closely related to L.
berthoudi.
Occurrence.- The Laramie formationof northeastern Colorado.
Genus Veloritina MEEK, 1872

Type-species.-Cyrena (C01'bicula) durkeei MEEK, 1870, Lower Cretaceous, Wyoming.
Diagnosis (emended).-Shell of medium
size, equivalve, inequilateral, subtrigonal,
provided with a fairly sharp posteriorcarina; the ratio of length to heightlarge; umbo prominent, rising above
hinge margin, recurved, prosogyrous,
anterior to mid-point; lunule clear, fairly deep; surface usual and some imbrications of growth ; pallial line fairly
deep, rounded sinus, but forming lessthan a semicircle (c-type); anterior adductor scar small but strongly impressed; dentition as formulated below:
Alii AI
All

3a

1 3b
2a 2b 4b

PI

Pili
PII

cardinals diverging from beak withweak grooves ; lateral long ; posterior

304

Yoshihisa OHTA

laterals very remote from cardinals.
Remarks.-MEEK (1872, p. 493) established Veloritina as a subgenus of Corbicula on Corbicula durkeei from the Bear
River formation. He clarified the subgeneric character, as being a remarkable
trigonal outline of shell and elongatedlateral teeth which are nearly or quitesmooth, rather than transversely striated. However, the crenulation of thelateral teeth is very faintly visible undera microscope, and may even be detectedwith the naked eye. And the crenulation of the lateral teeth can be seen not
only in the Corbiculidae but also in thelaterals of some genera of the Neomiodontidae and Arcticidae. Therefore,
in order to propose Veloritina as a genus
rather than a subgenus, I have emended
MEEK's definition in the following way:
the characteristics of this genus are a<:-type sinupalliated nature, a large ratioof height to length, and a clear lnnule.
In general, the presence of a lunule is
not characteristic of the Corbiculidae,
but Veloritina has a lunule. This exception is the most unusual found in
the Corbiculidae, but nevertheless, Veloritina is a valid genus in the Corbiculidae
as proved by its hinge nature as well
as by ecological evidence. Veloritina issimilar to Leptesthes in its sinupalliatednature, but differs from it in its outlineof shell and possession of a lunule. Thisis also similar to Corbicula s. s. andFulpia in many ways, but easily distinguishable from them by its sinupalliatednature, which is c-type as opposed tothe a-type Corbicula s. s. and the d-type
Fulpia.
V eloritina durkeei (MEEK)
Pl. 34, figs. 7-9
1869-1870. Cyrena (Corbicula) durkeei MEEK,
Am. Phil. Soc., Pr., 11, p. 431.

1870. Corbicula (Veloritina) durkeei, MEEK,
Hayden Surv., 4th Ann. Rept., p. 293,
294, 298.
1872. Corbicula ( Veloritina) durkeei, MEEK,
Hayden Surv., 6th Ann. Rept., p. 478,
494.
1876. Corbicula ( Veloritina) durkeei, MEEK,King Surv., 40th Par., 4, p. 167, pl.
16, fig. 6.
1878. Corbicula ( Veloritina) durkeei, WHITE,
Hayden Surv., 12th Ann. Rept., pt. 1,
p. 79, 91.
1883. Corbicula ( Veloritina) durkeei, WHITE,
U.S. Geol. Surv., 3rd Ann. Rept., p.
437, 473, pl. 8, figs. 8-11.
1895. Corbicula durkeei, WHITE, U.S. Geol.
Surv., Bull. 128, p. 28, 29, 36, 40, pl. 4,
figs. 1-4.
1907. Corbicula durkeei, VEATCH, U.S. Geol.
Surv., Prof. Pap., 56, p. 61, 62, pl. 8,
fig. 2.

Material.-Henderson Museum No.
10555, left internal mould and rightvalve (Pl. 34, Figs. 7, 8) ; from the Bear
River formation loc. Stowe Creek, E.
of Knight, Wyoming; No. 10541, left
valve (Pl. 34, Fig. 9), from loc. 9 miles
SE of Evanston, Wyoming (J. HENDERSON and E. G. SMITH Coli.) ; USGS 8148,
8166 (Plesiotype), from loc. Mouth of
Sulphur Creek and 7 miles north ofEvanston, Wyoming (WHITE Coli.).
Description.-Shell of medium size
highly inequilateral, trigonal to subtrigonal in outline, degree of inflation
medium, a little longer than high; test
fairly thick; antero-dorsal margin short,slightly concave in front of umbo, passing gradually into ventral; ventral margin broadly arched ; postero-dorsal margin unusually long, nearly straight,
turning somewhat abruptly toward
ventral; umbo prominent, high above
hinge margin, incurved, prosogyrous,
lying one-fourth of shell length fromfront; lunule fairly deep, large, clear
and circumscribed by anobtuse ridge

568.

Cretaceous Corbiculids in North America

305

Measurements in mm.Specimen

LengthHeightW Ci thickness)

H/L

w;H

10555 (bivalve)
)
(
)
(
)
(
, (
)

48.0
41.0
27.0
24.0
24.0

44.0
37.0
23.0
21.0
21.0

13.0
15.0
8.0
6.5
4.0

0.92
0.90
0.85
0.87
0.87

0.30
0.40
0.34
0.30
0.20

but ornamented in the same way as theother area ; posterior area behind it
crescentic, fairly contorted, occupying
about one-sixth of whole surface, definedby a fairly sharp posterior carina running from beak to postero-ventral angle;
convexity greatest near center; surface
marked with the usual lines and some
imbrications of growth. Internally, adductors slightly anisomyarian ; anteriorscar ovate, comparatively small andstrongly impressed ; posterior scar ovate,large, located close to posterior lateral
teeth ; pallial line shows a fairly deep
sinus, rounded, but forming less than asemicircle (c-type) ; dentition formula
given above; 2a small, trigonal, orthocline; 2b stout, acutely trigonal withgroove, prosocline; 4b elongated, ridgelike, subparallel to posterior dorsal margin; All long, curved near adductor,
poorly defined from 2a ; PII very remotefrom cardinals, long, linear but slightly
convex.
Observation and comparison.-The outline is fairly constant among about ahundred specimens which were collected
by HENDERSON and SMITH from the Bear
River formation of Wyoming. However,the position of the umbo is variable tosome extent. A fairly sharp posteriorcarination, inequilateral outline, a large
ratio of height to length, and a clear
lunule are the characteristics of thisspecies. This species is closely related
to Veloritina cleburni (WHITE, 1878) fromthe Laramie formation, because the twoare similar in every essential characteristics. This species is, however, different from V. cleburni in the presence ofconspicuous posterior carina and remarkable protruded umbo. This species
bears, perhaps, some rel:3emblance to
Veloritina occidental is MEEK and HAYDEN,
but it may be distinguished from thetypical forms of that species by its
more distinct posterior carina.
Occurrence.- The Bear River formation, Cretaceous, of southwestern Wyoming and adjacent territory.

Veloritina cleburni (WHITE)
Pl. 34, figs. 10-13
1878. Corbicula cleburni WHITE, Hayden
Surv., 12th Ann. Rept., pt. 1, p. 73,
pl. 23, fig 1.
1878. Corbicula cleburni, WHITE, Hayden
Surv., Bull. 4, p. 711.
1883. Corbicula cleburni WHITE, U.S. Geol.
Surv., 3rd Ann. Rept., p. 437, 473, pl.
20, figs. 7-9.
1907. Corbicula cleburni, HENDERSON, Univ.
Colo. Stud., 4, p. 152.
1920. Corbicula cleburni, HENDERSON, Colo;
Geol. Surv., Bull. 19, p. 38, 43, 44, 47,
48.
0MateriaL-USGS 9023 (Syntypes), fromJoe. Crow Creek, Colorado (WHITE Coli.).
Henderson Museum No. 12770, left valve(Pl. 34, Fig. lOa, b), from loc. E. of
Osgood, Colorado (J. HENDERSON andYoshihisa OHTA

306
Measurements zn mm.Specimen

LengthHeightW (! thickness)

H/L

W/H

13571 (bivalve)
12681 (right valve)13554 (left valve)
1292 (left valve)
12715 (right valve)

43.0
48.0
30.0
32.0
26.0

41.0
46.0
30.0
28.0
24.0

15.0
16.0
10.0
11.0
8.0

0.95
0.95
l. 00
0.87
0.92

0.36
0.34
0.33
0.39
0.33

E. G. SMITH Coli.); No. 17770, left valve(Pl. 34, Fig. 11), from loc. Weld, Colorado (H. A. AURAND Col!.); No. 12681,
right valve (Pl. 34, Fig. 12), from loc. E.
of Cornish, Colorado (J. HENDERSON and
E. G. SMITH Coli.); No. 13554, bivalve(Pl. 34, Fig. 13), from loc. Ditto.
Description.-Shel! of medium size,
highly inequilateral, subovate in outline;
moderately inflated, the ratio of height
to length fairly large; test fairly thick;antero-dorsal margin fairly sinuated in
front of umbo; ventral margin rounded;
posterior dorsal long, gently arcuated,
turning to posterior margin without
angulation; lunule not deep but fairly
wide, clear, circumscribed by an obtuse
ridge; obtuse posterior ridge from beakto posterior margin and near-escutcheon
absent or very obscure; surface marked
with fine concentric growth-lines andfairly regular concentric ribs also on
lunule. Internally, hinge teeth same as
the preceding species, but AO and PO
in left valve more well developed thanin V. occidentalis; adductors strongly
impressed, posterior one more or lesslarger than anterior; c-type pallial line.
Observation and 'comparison.- This
species certainly belongs to the genus
Veloritina since it has a lunule and thec-type pallial line. The outline of theshell of this species is comparatively
constant. A subovate outline and an
umbo which does not protrude notably
are the characteristic of this species.

WHITE (1878, p. 74) already pointed out
the similarity between this species andC. cytheriformis, but actually F. cleburni
is more similar to the adult form of F.
occidentalis than to C. cytheriformis,
although it is distinguishable from F.
occidentalis by its subovate outline ofshell. Perhaps this species is derived
from F. occidentalis, because AO and
PO in the left valve are more welldeveloped than they are in occidentalis.
This species also bears some resemblance to F. durkeei, especially in theoutline of shell, but it may be distinguished from the typical forms of thatspecies by its obtuse umbo and weak
posterior ridge.
Occurrence.-The Laramie formation,
Upper Cretaceous of northeastern Colorado.
F eloritina occidental is(MEEK andHAYDEN)Pl. 34, figs. 14-18; text-fig. 61856. Cyrena occidentalis MEEK and HAYDEN,
Phila. Acad. Nat. Sci., Pr., 8, p. 111,
279.
1860. Cyrena ( Corbicula ?) cytherijormis
MEEK and HAYDEN, Ditto., Pr., 12, p.
176, 432.
1872. Corbicula ( Veloritina) cytheriformis,
MEEK, Hayden Surv., 6th Ann. Rept.,
p. 478, 511.
1876. Corbicula cytheriformis, MEEK, Hayden
Surv., Mon., 9, p. 520, pl. 40, fig. 5.

568.

Cretaceous Corbiculids in North America

1878. Corbicula occidentalis, WHITE, Hayden
Surv., 12th Ann. Rept., pt. 1, p. 75,
pl. 21, fig. 3.
1878. Corbicula cytheriformis, WHITE, Ditto.,
pt. 1, p. 74, 80, pl. 21, fig. 4.
1878. Corbicula (Vel oritina) occidental is,
Wr·IITE, Hayden Surv., Bull. 4, p. 722.
1883. Corbicula occidentalis, WHITE, U.S.
Geol. Surv., 3rd Ann. Rept., p. 437,
473, pl. 17, figs. 6-7; pl. 23, figs. 1-6.
1883. Corbicula cytheriformis, WHITE, Ditto.,
p. 437, 473, pl. 22, figs. 1-6.
1885. Corbicula occidentalis, WHITEAVES,
Contr. Can. Pal., pt. 1, p. 7-9, 11, 40,
67, 68, pl. 1, fig. 3.
1885. Corbicula cytheriformis, WHITEAVES,
Ditto., p. 7, 8, 11, 68.
1897. Corbicula occidentalis, STANTON and
HATCHER, U.S. Ceo!. Surv., Bull. 257,
p. 44, 52, 111, 120, 121.
1897. Corbicula cytherifonnis, STANTON and
HATCHER, Ditto., p. 33, 38, 41, 44, 52,
111, 120, 121.
1910. Corbicula occidentalis, HENDERSON,
Univ. Colo. Stud., 7, p. 147, 148.
1912. Corbicula occidentalis LEE, U.S. Geol.
Surv., Bull. 510, p. 34, 35.
1912. Corbicula cytheriformis, LEE, Ditto., p.
33, 35, 44, 219, pl. 16, fig. 6.
1916. Corbicula cytheriformis, STANTON, U.S.
Geol. Surv., Prof. Pap. 98, p. 310, 316,
pl. 82, fig. 4.
1920. Corbicula
cytheriformis, STANTON,
Ditto., 128, p. 29, pl. 5, fig. 4.
1924. Corbicula
cytheriformis, REESIDE,
Ditto., 134, p. 21.

Material.-USGS 2133 (Holotype), 2134,
2135 (Paratypes), from loc. Bad Landsof Judith River, and near Fort Benton,

307

Montana (MEEK Col!.) ; USGS 8112
(Plesiotype), from loc. Black Butte Station, Wyoming, and Yampa Valley, Colorado (WHITE Col!.) ; Henderson Museum
No. 11643, left and right internal moulds(Pl. 34, Figs. 14, 18), from loc. NW of
Fruitland, San Juan Co., New Mexico(H. K. AURAND and D. E. LOUNSBERRY
Coil.) ; No. 17830, left internal mould(Pl. 34, Fig. 16), from loc. E. of Fosston,Colorado (]. HENDERSON Col!.) ; No. 7913,
right valve (Pl. 34, Fig. 17), from loc.
Dru Creek, SE of Torrinton Goshen Co.,
Wyoming (H. A. AURAND Col!.) ; No. 2390,
bivalve, from the upper Mesa Verdeformation loc. W. of Meeker, Colorado(]. HENDERSON Col!.).
Description.-Shell of medium size,
inequilateral, variable in outline fromtrigonally ovate to orbicular, moderately inflated, the ratio of height to lengthvery large; test fairly thick; anterodorsal margin fairly concave in frontof umbo; ventral margin rounded; postero-dorsal long, gently arcuated, turning to posterior margin with obtuse
angulation; lunule not deep, but large,
clear, circumscribed by an obtuse ridge;
escutcheon clear, defined by a fairly
sharp ridge; surface marked with fineconcentric growth-lines and fairly regular, strong, concentric ribs; lines andribs absent on lunule. Internally, anterior rather than posterior adductor
strongly impressed; pallial sinus c-type;hinge similar to the preceding; cardinals

Measurements in mm.Specimen

7913 (bivalve)()(
2390 (
11634 ()))

LengthHeightw a thickness)

I-I;L

W!H

40.0
35.0
29.0
22.0
31.0

41.0
38.0
27.0
18.0
26.0

13.0
13.0
8.0
6.0
9.0

l. 02
1. 08
0.93
0.81
0.83

0.31
0.34
0.29
0.33
0.34

308

Yoshihisa OHTA

stout, divergent from beak; 3a small,
opithocline, formed by a thickening oflateral Alii at its posterior end; 1 stout,
trigonal, orthocline, situated below beak;3b stout, elongated, prosocline; laterals
strong, long; posterior ·laterals very remote from the cardinals; AI elongated,
fairly strong and straight; Alii formed
by a thickening of anterior shell margin;
PI remote from cardinals, long andstrong ; Pili long, formed by thickeningof posterior shell-margin.
Observation and comparison.- This species certainly belongs to the genus V eloritina, having a lunule, protruded umbo,<:-type pallial sinus and a large ratio ofheight to length. An oblong ovate outline and fairly regular concentric ribson the surface are the characteristicsof this species. The outline of thisspecies varies greatly during the processof growth; it is generally · subtrigonalin the immature stage, but becomes<>vately oblong with a gradually increasing ratio of height to length in theadult stage (see Text-fig. 6).

Text-fig. 6. The variation of outline
of Veloritina occidentalis.

WHITE (1877, p. 209) once considered
this species to be identical with C.
cytheriformis, but preferred to regard

them as separate species because of thedifference in their. outline of shell. On
the other hand, STANTON· and HATCHER(1905, p. 111) indicated that there is anintermediate form between V. occidentalis and . C. cytherijormis, which occur
in the Laramie formation of Wyoming
and northwestern Colorado, as well as
in the "Western Laramie" of Canada.
These two species are apparently ·notspecifically separable, ·but STANTON and
HATCHER treated them as comple.tely
separate species. Comparing the halotype of C. cytherijormis MEEK and
HAYDEN (MEEK, 1876, pl. 40, figs. 5a-e)
with the immature forms (Text-fig. 6)of this species, the two species resemble
each other inseparably in the outline ofshell. I prefer at present to regard C.
cytherijormis as· synonymous with V.
occidentalis, because the variable outline
of C. cytherijormis is included in therange of variation of outline of V. occidentalis, and both species coexist \Vitheach other in many cases (HENDERSON,
1910, p. 148; BOWEN, 1915, p. 111; STANTON and KNOWLTON, 1897; STANTON and
HATCHER, 1905, p, 111).
The younger forms of this species
are very similar to V. durkeei in outline, but the adult form differs fromthat of V. durkeei. I presume this species is probably derived from V. durlzeei,
because they are morphologically andstratigraphically closely related to eachother. Tetoria (Paracorbicula) yoshimoensis (OHTA, 1965, p. 168) from the Lower
Neocomian in Japan is somewhat similar
to this in the outline of shell, but differsfrom this in the sinupalliated nature.
Occurrence.-Ranges geologically fromthe Judith River formation to the Lance
formation and geographically from northwestern Colorado through Wyoming andMontana to Canada and eastward into
the Dakotas.

568.

Cretaceous Corbiculids in North America

Geloina ? rodecki, new species
Pl. 34, figs. 1, 2

Material.- The holotype (Henderson
Museum No. 13577) is an incomplete
right valve which was collected by ]. W.
WILLIAMS from the Laramie formation
at Ft. Morgan, Colorado.
Description.-Shell of medium size,
equivalve, highly inequilateral, subelliptical in outline, inflation of shell medium; test fairly thick; antero-dorsal
margin fairly sinuated in front of umbo;
ventral margin broadly rounded, andturning to antero- and postero-margins
without obtuse angulation; umbo notprominent, incurved, prosogyrous, lying
at a fourth of shell-length from front;
without escutcheon and lunule; an obtuse ridge running from beak to posteroventral angle; convexity greatest near
center; surface marked with fine growthlines and some weak imbrications. Internally, adductors slightly anisomyarian; anterior adductor scar ovate,
comparatively small and strongly impressed; posterior one subsquare, large,
located close to posterior lateral teeth;
D.entition cyrenoid as formulated below :
Alii
AI
All

3a

1
2a

2b

3b
4b

PI

Pili
Pll

.3a very small, opisocline, formed by athickening of lateral Alii at its posteriDr end; 1 stout, trigonal, orthocline,
situated more anterior rather than below
the beak; 3b stoutest, fairly long withgroove, prosocline ; 2a small, opisocline,
formed by a thickening of lateral All ;2b stout, bifid, more or less prosocline,
placed below the beak; 4b long but thin,very prosocline; anterior laterals shorter
than posterior ones ; AI short, curved,
D.istinctly crenulated; Alii thin but long,connected with 3a; All short, fairly
stout, curved, finely crenulated, con-309

nected with 2a; posterior laterals very
remote from the cardinals ; PI and PII
long, fairly stout, finely crenulated ;· Piliformed by a thickening of posterior shell
margin.
Measurements.- The holotype (No.
13577, right valve) : length of shell about
30 mm, height about 25 mm and ! thickness about 10 mm.
Observation and comparison.- I foundthis species among the specimens which
are named Corbicula cardiniaejormis
WHITE from the Laramie formation at
Ft. Morgan, Colorado (No. 13577, Coli.
]. E. WILLIAMS). The four specimens
are all incomplete, but I could examine
almost all the features except the nature of pallial sinus. Particularly, thenature of hinge can be observed distinctly.
This species is certainly related to
the Corbiculidae, having the cyrenoid
dentition and coexisting with Hendersona cardiniaefonnis.
Extraordinary
short anterior laterals, the connectionof 2a with All, and bifid cardinals arethe. characteristics of this species. These
characteristics of hinge cannot be seenin an already known Corbiculidae of theLaramie formation. So far as I observed
STEPHENSON' illustration and description(1952), the present species is similar to
Dentonia leveretti (CRAGIN) from the
Woodbine formation (Cenomanian) of
Texas in the short anterior laterals.
However, in D. leveretti, 2a is not connected with All and 3a appears stronger
than in G. ? rodecki. At first, I considered its establishment as a new genus,
but the specimens are too incomplete topropose a valid genus. In many of its
characteristics, this species is closely
related to Geloina zeylanica LAMARCK,
the type species of the genus, but differs from the latter in the nature of its
cardinals. That is, 3a and 2b are not

310

Yoshihisa OHTA
Explanation of Plate 32
Hendersona subelliptica (MEEK and HAYDEN)

Fig. 1. Left valve (Henderson Museum No. 12664: Laramie formation, NW of BriggsdaleColorado. J. HENDERSON and E.G. SMITH Coli.).
Fig. 2a. Right external cast (No. 12664).
Fig. 2b. Right internal cast (No. 12664).
Fig. 3. Left valve (No. 12664).
Fig. 4. Right valve (No. 12664).
Fig. 5. Left valve (No. 12664).
Fig. 6. Left valve (No. 12664).
Fig. 7. Left valve (No. 12664).
Fig. 8. Right internal mould (No. 12633: Laramie formation S. of Cornish, Colorado. J.
HENDERSON and E.G. SMITH Coli.).
Fig. 9. Right valve (No. 12633).
Hendersona umbonella (MEEK)

Fig. 10. Right internal cast (No. 13550: Laramie formation S. of Cornish, Colorado. J. HENDERSON and E.G. SMITH Coli.).
Fig. 11. Left internal cast (No. 13550).
Fig. 12. Right valve (No. 12648: Laramie formation, S. of Cornish, Colorado. J. HENDERSON
and E.G. SMITH Coli.).
Fig. 13. Right valve (No. 12764: Laramie formation, E. of Osgood, Colorado. J. HENDERSON
and E.G. SMITH Coli.).
Fig. 14. Left valve (No. 7782: Fox-Hills sandstone, 1 mile N. and 1 mile W. of NW. Cornerof Morgan, Colorado. J. HENDERSON and E:G. SMITH Coli.).
Fig. 15a. Right valve (No. 12700: Laramie formation, SE of Fosston, Colorado. J. HENDERSON
and ~.G. SMITH Coli.).
Fig. 15b. Right internal cast (No. 12700).
Fig. 16a. Left external cast (No. 12700).
Fig. 16b. :Left intermit cast (No. 12700).
Fig. 17. Left valve (No. 12764: Laramie formation, E. of Osgood, .Colorado. J. HENDERSON
and E.G. SMITH Coil.).
Fig. 18. Left valve (No. 12764).
Hendersona cardiniaeformis (WHITE)

Fig. 19. Left valve (No. 5255: Laramie formation, SE of Cornish, Colorado. J. HENDERSON
and E.G. SMI,TH Coil.).
Fig. 20. Left valve (No. 13549: Laramie formation, E. of Cornish, Colorado. J. HENDERSON
and E.G. SMITH Coli.).
Fig. 21. Left valve (No. 13262: Laramie formation, E. of Cornish, Colorado. J. HENDERSON
and E.G. SMITH Coli.).
Fig. 22. Left valve (No. 5255).
Fig. 23. Left internal cast (No. 12772: Laramie formation, E. of Osgood, Colorado. J. HENDERSON and 'E.G. SMITH Coli.).
Fig. 24. Right internal mould (No. 2041: Laramie formation, aboveCrow'Creek 'Dam, 25 miles
NE of Greeley, Colorado. J. HENDERSON and H.W. CLATWORTHY .Col!.).
Fig. 25. Left internal mould (No. 2041).
Fig. 26. Left internal mould .(No. 5221: NE of Osgood, Colorado, near type locality. J. HENDERSON .and E.G. SMITH Coli.).
Fig. 27. Left internal mould (No. 2041).

OHTA :

Cretaceo~ts

Co1·biculids in N01·th Ame1·ica

Plate 32

568.

Cretaceous Corbiculids in North America

hdependent teeth, but are connectedwith Ail and Alii, and the degree ofbifidity of the cardinals is more distinct
than in those of the latter. As far as
I can tell, this species is the oldest one
in the Geloina group. It is named inhonor of Prof. Hugo H. RODECK who
studied the Corbiculidae with Prof.
HENDERSON and is contributing to the·Operation of the Colorado Museum. In
this paper, I have tentatively treated it.as one species of Geloina.
Occurrence.- The Laramie formation·of northeastern Colorado.
IV.

Concluding remarks(1) As a result of reexamining the spe-cimens of Corbiculidae which are kept
in the University of Colorado Museum,ten species under four genera are re·cognized.*
Considering the ontogeny and phylogenetic relation between the species,
their stratigraphic relations and their·Occurrences, these species can be summarized as shown in text-fig. 7.

(2) The genus Vel oritina is characterized by the c-type sinupalliated natureand by a lunule and remarkable subtrigonal outline of shell. This is aunique group in the Corbiculidae andthe oldest one in North America. This
genus includes V. durkeei, V. occidentalis[=C. cytheriformis] and V. cleburni. Theinterrelation of these species is shownin text-fig. 7.
(3) The genus Leptesthes which is characterized by the elliptical outline of shelland the c-type sinupalliated nature includes L. fracta, L. berthoudi and L.
augheyi. The elliptical form of shell isalso one of the unique characteristicsof the Corbiculidae. L. berthoudi and
L. augheyi are closely related to eachother but it is difficult to determine
whether these two species belong to
Leptesthes or Veloritina. I have referredthem to the genus Leptesthes becauseof the absence of a lunule.
(4) The genus Hendersona which ischaracterized by the b-type sinupalliated nature includes H. subelliptica, H.
umbonella [=C. obesa] and H. cardiniaeUppc·r Crcbccous

Lower Cretaceous
AptianCcnomCJ.niun- S:mtonbn~IacstricbtianCampaninn

illonbna group

Dnkota s. s.

311Coll)r:ldo gro'Jp

Pierre sh.

(L:namio formation

Fox Hill s. s./r~.:wcc form:1tion
llellde!'801W

Jl. nw•·,·upisthrr
subdlipticrt
II. umba11elfG.
l/. rrtnliniaefot•mis

I.•J'lf':Jthes

LI~. br·rtlwucli[., IIU!lfW/Ii

Text-fig. 7.

The relationship among some Cretaceous speciesof Corbiculidae in North America.

* Besides these species, there are some other species which are described from the Cretaceous
formations in North America, but I have had no opportunity to examine them.

312

Yosh.ihisci OHTA

formis. This was the most flourishinggroup in the Laramie formation. The
relations among· these three species areshown in text-fig. 7.
(5) Geloina ? rodecki n. sp. is found in
the specimens which were named Corbicula cardiniaeformis WHITE from theLaramie formation at Ft. M?rgan, Colorado. Perhaps this species is the oldest
one in the Geloina group.
(6) Comparing the representatives of
the Cretaceous Corbiculidae with thoseof Asia and Europe (CASEY, 1952), there
are many unique species . in North
America. I presume these species developed endemically without any relation to the groups of other areas.
On the other hand, I could not
trace the ancestry of the Corbicu!idae
in North America. This is a mootquestion which should be resolved infuture.

References
BowEN, C.F. (1915) : The stratigraphy of
the Montana group, with special reference to the position and age of theJudith River formation in north-central
Montana. U.S. ·Geol. Survey, Prof. Pap.
90, l, p. 95-153.
CASEY, R. (1952) : The pelecypod family
Corbiculidae in the Mesozoic of Europe
and the Near East. jour. Washington
Acad. Sci., 45, (12), p. 366-372.
CALVERT, W.R., BEEKLY, A.L., BARNETT,·v.H. and PisHEL, M.A. (1914): Geologyof the Standing Rock and Cheyenne River
Indian reservations. U.S. Geol. Survey,
Bull. 575.
DALL, W .H. (1903) : Contributions to the
Tertiary fauna of Florida. Wagner Free
Inst. Sci., Tr., vol. 3.
HENDERSON, }. (1907) : Scientific expedition
to northeastern Colorado. Paleontology:
Account of collections made. Univ. Colo.
Stud., vol. 4, p. 149-152.

Explanation of Plate 33
Leptesthes fracta (MEEK)
Fig. 1. Right internal cast (Henderson Museum No. 10523: Laramie formation, Black Buttes,
Wyoming. J. HENDERSON and E.G. SMITH Coli.).
Fig. 2. Right val've (No. 10523).
Fig. 3. Left internal mould (No. 1.0523).
Fig. 4. Right internal mould (No. 10523).
Fig. 5. Left internal mould (No. 10485: Mesaverde formation, 6 miles E. of Point of Rocks,
Wyoming. }. HENDERSON and E.G. SMITH Coli.).
Fig. 6. Left internal mould (No. 17859: Laramie formation, T. 7, N.R, 61W., Weld, Colorado.
J. HENDERSON and E.G. SMITH Coli.).

Leptesthes berthoudi (WHITE)
Fig. 7. Right internal cast (No. 12699: Laramie formation, SE of Fosston, Colorado. J. HENDERSON and E.S. SYIITH Coli.).
Fig. 8. Left internal cast (No. 12699).
Fig. 9. Left valve (No. 12724: Laramie formation, E. of Fosston, Colorado. J. HENDERSON
and E.G. SMITH Coli.).
Fig. 10. Left valve (No. 12724).
Fig. 11. Right valve (No. 17827: Laramie formation, 1 or 2 miles E. of Fosston, Colorado. J.
HENDERSON Coli.)

OHTA:

Cretaceous Corbiculids in North America

Plate 33

568.

Cretaceous Corbiculids in North America- - (1910) : Fossil invertebrates from northwestern Colorado. Univ. Colo. Stud., vol.
7, p. 146-149.
- - (1920) : The Cretaceous formations ofnorthwestern Colorado plains. Colo. Geol.
Surv. Boulder. Bull. 19, p. 7-57.
- - (1935) : Fossil non-marine Mollusca ofNorth America. Geol. Soc. Am., Spe.
Pap. no. 3, p. 1-290.
LEE, W.T. (1912): Coal fields of Grand
Mesa and the West Elk mountains," Colorado. U.S. Geol. Survey, Bull. 510, p.
7-219, pls. 79-83.
MEEK, F.B. and HAYDEN, F.V. (1856): Descriptions of twenty-eight new speciesof Acephala and one Gastropod, fromthe Cretaceous formations of Nebraska
Territory. Phi. Acad. Nat. Sci., Pr.,
vol. 8, p. 70-72.
- - (1860a) : Descriptions of new fossil
remains collected in Nebraska and Utah,
by the exploring expeditions under thecommand of Capt. ].H. SIMPSON, of U.S.
Topographical Engineers. Philadelphia
Acad. Nat. Sci., Pr., vol. 12, p. 308315.
- - and - - (1860b): Descriptions of neworganic remains from the Tertiary, Cretaceous and Jurassic rocks of Nebraska.
Philadelphia Acad. Nat. Sci., Pr., vol.
12, p. 175-185.
- - and - - (1860c): Systematic catalogue,
with synonymy etc., of Jurassic, Cretaceous and Tertiary fossils collected in.
Nebraska by the exploring expeditions
under the command of Lieut. G.K. WAR·
REN, of U.S. Topographical Engineers.
Ditto,_ p. 417-432.
- - (1869) : A preliminary list of fossils,collected by Dr. HAYDEN in Colorado,
New Mexico and California, with brief
descriptions of a few of the new species
Am. Phi. Soc., Pr., vol. 2, p. 425-431.
- - (1870a) : Preliminary paleontological report, ·consisting of list of fossils, withdescriptions of some new typ'es, etc.
Hayden Surv., 4th Ann. 'Rept., p. 287-318.
- - (1870b) : Descriptions of fossils collected by the U.S. Geol. Survey under the
charge of Clarence KING Esq. Philadel-313

phia Acad. Nat. Sci., Pr., vol. 22. p. 5664.
- - (1872) : Preliminary paleontological report, consisting of lists and descriptionsof fossils, with remarks on the ages of
the rocks in which they were found, etc.
U.S. Geol. Geogr. Survey, Terr., 6th Ann.
Rept., p. 431-541.
- - (1875): Notes on some fossils from near
the eastern base of the Rocky Mountains,
west of Greeley and Evans, Colorado, andsome others from about two hundred
miles farther eastward, with descriptionsof a few new species. U.S. f5eol. Geogr.
Survey, -Terr., Bull. 2nd ser., voL 1, p.
39-47.
- - (1876) : A report on the invertebrate
Cretaceous and Tertiary fossils of theUpper Missouri Country.
U.S. Geol.
Survey, Terr., Rept., vol. 9, p. 521, pl.
40.
- - (1877): Paleontology. Cretaceous species. U.S. Geol. Expl. '40th Par., Rept .•vol. 4, pt. 1, 140-182.
OHTA, Y. (1964): On the Corbiculidae fromthe Lower Neocomian of Japan. · Geol.
Rept. Hiroshima Univ.; no. 14, p. 165-171,
pls. 12-13.
REESIDE, ].B. (1924): Upper Cretaceous andTertiary formations of the western partof the San Juan Basin, Colorado and New
Mexico. U.S. Geol. Survey, Prof. Pap .•134, p. 1-70.
STANTON, T.W. and KNOWLTON (1897):
Stratigraphy and paleontology of theLaramie and related formations in Wyoming. Geol. Soc. America, Bull. 8, p.
127-156.
- - an.d HATCHER (1905): Geology andpaleontology of the Judith River beds.
U.S. Geol. Survey, Bull. 257, p. 1-174.
- - (1916): Non-marine Cretaceous Invertebrates of the San Juan Basin. U.S. Geol.
Survey, Prof. Pap., 98-R, p. 309--319, pls.
79-83.
- - (1920): The fauna· of· the Cannonballmarine member of the Lance formation.
U.S. Ceo(. Survey, Prof. Pap., 128, p. 149, pls. 1-9.
STEPHENSON, L.W. (1952): The larger in-314

Yoshihisa OHTA. vertebrates fossils of the Woodbine formation (Cenomanian) of Texas. U.S.
Geol. Survey, Prof. Pap., 242, p. 1-217,
pis. 8-59.

VEATCH, A.C. (1907) : Geography and geology of a portion of southwestern Wyoming. U.S. Geol. Survey, Prof. Pap.,
56.

. Explanation of Plate 34
Geloina? rodecki sp. nov.
Figs. la, lb, lc (Holotype) : Right external cast, right internal cast and anterior sidesview(Henderson Museum No. 13557: Laramie formation, Ft. Morgan, Colorado. J.E. WILI.IAMS
Coil.).
Fig. 2. Right valve (No. 13577).

Leptesthes augheyi (WHITE)
Figs. 3a and 3b. Left external and internal casts (No. 12698: Laramine formation, SE of
Fosston, Colorado. J, HENDERSON and E.G. SMITH Coli.).
Fig. 4. Right internal cast (No. 12698).
Fig. 5. Left valve (No. 12698).
Fig. 6. Left valve (No. 12698).

Veloritina derkeei (MEEK)
Fig. 7. Left internal mould (No. 10555: Bear River formation, Stowe Creek, E. of Knight,·
Wyoming. J. HENDERSON and E.G. SMITH Coli.).
Figs. Sa and 8b. Right valve and show its lunule (No. 10555).
Fig. 9. Left valve (No. 10541: Bear River formation, 9 miles SE of Evanston, Wyoming. J.
HENDERSON and E.S. SMITH Coil.).

Veloritina cleburni (WHITE)
Figs. lOa and lOb. Left external and internal casts (No. 12770: Laramie formation, E. of
Osgood, Colorado. J. HENDERSON and E.G. SMITH Coli.).
Fig. 11. Left valve (No. 17770: Laramie formation, Weld, Colorado. H.A. AuRAND Coli.).
Fig. 12. Right internal cast (No. 12681: Laramie formation, E. of Cornish, Colorado. J. HENDERSON and E.G. SMITH Coil.).
Fig. ·13. Shows a lunule (No. 13554: Laramie formation, E. of Cornish, Colorado. J. HEN·DERSON and E.G. SMITH Coil.).

Veloritina occidentalis (MEEK and HAYDEN)
Fig: 14. Right internal mould (No. 11643: Fruitland formation, NW of Fruitland, San Juan
Co., N. Mexico. H.S. AuRAND and D.E. LouNSBERRY Coli.).
Fig. 15. Left valve (No. 2390: Mesa Verde formation, W. of Meeker, Colorado. J. RENDER·
soN Col!.).
Fig. 16. Left internal mould (No. 17830: Laramie formation, E. of Fosston, Colorado. J.
HENDERSON Coil.).
Fig. 17. Right valve (No. 7913: Lance formation, Dru Creek, SE of Torrinton Goshen Co.,
Wyoming. H.A. AuRAND Coil.).
Fig. 18. Left internal mould (No. 11643).

OHTA:

Cretaceous Corbiculids in North A1nerica

Plate 34

568.

Cretaceous Corbiculids in North America

WHITE, C.A. (1878a) : Contributions to invertebrate paleontology. no. 4: Fossilsof the Laramie group. Hayden Survey,
12th Ann. Rept., pt. 1, p. 72-80, pis. 2125.
- - (1878b): Description of new species of
invertebrate fossils from the Laramiegroup. Bull. U.S. Geol. Geogr. Survey,
Terr., 4, p. 707-719.
- - (1879a) : Contdbutions to invertebrate
paleontology, no. 1: Cretaceous fossils of
the western States and Territories. U.S.
Geol. Ceo gr. Survey, Terr., 11th Ann.
Rept., p. 273-319.
- - (1879b): Report on the paleontologicalfield-work for the season of 1877. U.S.
Geol. Geogr. Survey, Terr., 11th Ann.
Rept., p. 161-272.
- - (1882): New molluscan form from theLaramie and Green River groups, withdiscussion of some associated forms
here-to fare known.
Proc. U.S. Nat.

315

Museum, vol. 5, p. 94-99, pis. 3-4.
- - (1883a) : Contributions to invertebrate
paleontology. no. 4. Fossils of the Laramie group. U.S. Geol. Survey, Terr.,
12th Ann. Rept., pt. 1, p. 49-103.
- - (1883b): A review of the non-marine
fossil Mollusca of North America. U.S.
Geol. Survey, 3rd Ann. Rept., p. 409-550,
pis. 1-32.
- - (1891) : Correlation papers. Cretaceous.
U.S. Geol. Survey, Bull. 82.
- - (1895): The Bear River formation andits characteristic fauna.
U.S. Geol.
Survey, Bull. 128, p. 1-108.
WHITEAVES, ].F. (1885): Contributions to
Canadian paleontology. Can. Geol. andNat. Hist. Surv., vol. 1, pt. l.
- - (1895): Notes on some of the Cretaceous fossils collected during Captain
PALLISER's explorations in British North
America in 1857-60. Roy. Soc. Canada,
Trans. sect. 4, p. 101-117.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 79, pp. 316-336, pls. 35, 36, Sept. 30, 1970

569.

MIOCENE BRYOZOA FROM SOUTHWEST HOKKAIDO, JAPAN*TOMOKO HAY AMI
Institute of Geology and Paleontology, Faculty of Science,
Tohoku University, Sendai, Japani§J¥j;fl::;i41J:i!li.J~ I? O)J:j:I*JTUU:. it 91 :vt*' B*O)J:j:I;J:'fii!t C. It 911i::fiiC .-:> v' "( O)$fl:i~d'it.J:\·'

i.J~, 4-@l;JI::;imihli*fi~»W114-~IHJ;fi::;JIHc.11l:~i'~J'l.7DH~li:J>:'6-l'm~ (1\III~;V\'D iPI?~.i!fi'~ clt!±"tfi::fi':!::f*:*i' ~ ~~:(t:fJ}t~O)-:t:· c.:::. fC$fH§·i' ~, 30 I~ 39 fJ!l:(t: PliE L-ITL;,I& u~,
IIJJ'f\:fc..-:>v'"Cf'i~f&O)IiJf)tfcf~.-:>

c. c. ;stJ;~v',

During stratigraphical work in the
Imagane-cho area in the southwesternpart of Hokkaido in the summers of1967 and 1968, the writer was fortunate
in collecting abundant specimens of
Bryozoa from the Kaigarabashi Sandstone Member of the Kunnui Formation(SAWADA, 1962). These bryozoan specimens, the first record of Miocene Bryozoa from Hokkaido, from the scope of
the present article. The stratigraphic
position of the Kaigarabashi Sandstone
Member is shown in Table 1.
The locality of the fossil bryozoan
specimens is the stream cliff of theTane-gawa immediately northeast of
the Kaigarabashi bridge. At this locality richly fossiliferous sandstone facies
are exposed ; the fossils are mostly
scallops (T. NAGAO and Y. SASA, 1934;K. KUBOTA, 1950; K. MASUDA and Y.
SAWADA, 1961; S. KANNO, 1962), which
occur with the valves detached or intact, and in both cases the shells are
generally parallel with the bedding.

!ill'f!l:tl;iiiJ:Q,

iili 7Jc

1J~:r

The bryozoan specimens show twomodes of occurrence, one is attached to
the valves of the molluscan shells, andthe other is as isolated broken stems,
branches or fragments of encrusting
forms. Their preservation is good asshown in the annexed plates.
The bryozoans identified from the
Kaigarabashi Sandstone Member of the
Kunnui Formation are listed in Table 2.
From the bryozoan species listed inTable 2, it is evident that the fauna isinteresting in yielding species hitherto
known only from the Paleogene of North
America, a few that have been recorded
from the Neogene of New Zealand, many
that extend their geographical distribution to low latitudes, some that havebeen known only from the temperateseas of the North Pacific, besides a few
cosmopolitan species.
This suggeststhat the Bryozoa fauna of the Kaigarabashi Sandstone Member may be amixed one, due either to the mixing ofwarm and temperate waters at the particular geographical position, or to thepossibly changing paleogeographical conditions of the sea area at that time.
However, it is also to be kept in mind
that since our present knowledge con-

* Received January 6, 1970; read at theGeneral Meeting of the Paleontological Society of Japan, held at the Kagoshima University, Kagoshima, November 29, 1969.

316

569.

317

Miocene Bryozoa from Hokkaido

Table 1. Stratigraphic classification of the rocks distributedin the Setana-Irnagane area in southwest Hokkaido(after SAWADA, Y., 1962).

Age
Holocene
Pleistocene
Late Pliocene
Early Pliocene
Late Miocene

Formationlbicknes~(In meters

Alluvial Deposits
Lower Terrace Deposits

15-

20

Higher Terrace Deposits

20-

25

Minamitoshibetsu Formation

150- 250

Chinkope Formation.s"lianaishi Conglomerate Member
Kuromatsunai Formation

1:il- 180
100- 400

0- 700

Vakumo Formation
Kaigarabashi r~ LKayano Rhyolite
stone Member
ember

Early Miocene

Kunnui Formation~Chinkopegawa

30- 1150

esitic Agglomerate
Membe..!

<E"itaizawa Conglomerate--z -Member

Pre-TertiaryPre- Tertiary Basements

serning the Miocene and Pliocene bryozoan fauna of japan is inadequate, thepeculiarities of the fossil fauna may be
only apparent. It is thought that any
conclusions concerning the determination of the geological age and correlation of the fauna with other areas,
should wait further studies on thebryozoan fauna of japan. Thus the
purpose of the present article is to record the bryozoan fauna from the Kunnui Formation.
The bryozoan fauna as a whole represents a shallow water assemblage
judged to be not far from land, andone that lived in clear water and on aclean bottom, that is to say, free fromthe deposition of muddy sediments. The
thermal conditions of the sedimentarybasin are thought to have been temperate to warm so far as can be judged
from the known geographical distributions of the species identified.
The geological age of the Kaigarabashi Sandstone Member inferred from·the scallops is Early Miocene according
to the morphogenesis of Nanaochlamys
notoensis (YOKOYAMA) studied by K.
MASUDA (1960), and from the pectinids
described by K. MASUDA and Y. SAWADA (1961).
At this place the writer wishes to318

Tomoko HA YAM I
Table 2. Bryozoan species identified from the Kaigarabashi
Sandstone Member of the Kunnui Formation.
Genus and species

Callopora corniculifera (H!NCKs)
Callopora aurita (HINCKS)
Callopora cf. whiteavesi NoRMAN
Crassimarginatella kumatae (OKADA)
Pyrulella corbula (HrNcKs)
Membraniporidra sp. A.
Tegella aquilirostris (O'DONOGIIUE)
Tegella robertsonae O•Do:'iOGHUE
and O'DOi'iOGIIUE
Tegella unicornis (FLEMING)
Hincksina cf. periporosa CANU and BASSLER
Ellisina levata (HINCKs)
Cauloramphus (?) sp. A.
Onychocella subsymmetrica CANU
and BASSLER
Micropora cor!acea (JoHNSTON)
Verminaria areolae SAKAKURA
Microporina articulata (FABRICIUS)

Monoporella fimbriata CANU and BASSLER
Cellaria diffusa RoBERTSON

Figularia cf. carinata (WATERS)
Figularia crassicostulata CANU and BASSLER
jullienulla sp. A.
]ullienulla sp. B.
Membraniporella cf. bicornis CANU
and LECOINTRE
Reginella nitida OsBURN
Puellina setosa (WATHRS)
Hippothoa fragellum MANZO"'I

Distribution
Recent, California (11-70 m). Pleistocene of
California
Recent, Alaska (229m) and both sides ofNorth Atlantic
Recent, Alaska (0-22 m)
Recent, Straits of Corea (97-llOm) and Japan(tidal zone to shallow water)
Recent, Australia (tidal zone-50 m), New Zealand, East Indian Ocean to Japan. Pleistocene of New Zealand, Kikai-jima and Chiba
Recent, British Columbia
Recent, Alaska to California. Pleistocene of
Chiba
Recent, North Pacific from Alaska to California ahd North Atlantic
Recent, Cuba (261-368 m), Gulf of Mexico(55 m) and Florida Strait (102m)
Recent, British Columbia (27-37 m) and California (49 m)
Recent, Philippine Islands (35-439 m). Pleistocene of Kikai-jima and Chiba
Recent, Cosmopolitan. Eocene of North Carorina. Miocene of New Zealand. Pleistoceneof Chiba
Pleistocene of Chiba
Recent, Cape Tsuika, Japan Sea, off Torishima, Paramushir Island, California, Greenland, and Queen Charlotte Island. Mioceneof Nato (Ishikawa) and Hokkaido. Plioceneof Sado (Niigata)
Recent, Philippine Islands (35-439 m). Pleistocene of Kikai-jima and Chiba
Recent, Galapagos Islands (55 m), according
to OsBURN (1950), the known vertical distribution is from shore to 216m. Pleistocene
of California
Recent, New Zealand. Pliocene of New Zealand
Eocene of Florida

Miocene of Touraine, France
Recent, Southern California
Recent, Oregon (37-110 m), Madeila and Naples, British Columbia, and British Islands
Recent, Pacific coast from Mexico to Panama,
Columbia, Peru and Galapagos Islands (shallow water to 183m). Pliocene of Italy and
New Zealand569.

Miocene Bryozoa from Hokkaido

319

Table 2. (Continued)

Umbonula arctica (SARS)
Dakaria subtorquata (D'0RBIGNY)"Schizoporella" scissa BROWN
Microporella ciliata (PALLAS)
Microporella lunijera (HASWELL)
Microporella sp. A.
Eurystomella bilabiata (HINCKs)
Mucronella labiata LEVJNSEN
Parasmittina sp. A.
Rhamphostemella hincksi NoRDGAARD
Rhamphostomella spinigella LoRENZ
Parella acutirostris SMITT
Perigastrella rectilineata CANU and BASSLER

offer her thanks to Professor Kotora
HATAI of the Institute of Geology andPaleontology, Tohoku University, for
his kindness and guidance throughout
the course of the present work. She isindebted to, Dr. Sumio SAKAGAMI of the
Department of Geology, Faculty of Education, Ehime University, for his kindness and encouragement, Dr. Shizuo
MAWATARI of the Research Institute of
Nat ural Resource, Tokyo, for providing
the writer with several of his publications, and Mr. Kimiji KuMAGAI of theInstitute of Geology and Paleontology,
Tohoku University, for his photographic
work.
Descriptions and Remarkson the Bryozoa

Phylum Bryozoa EHRENBERG, 1831
Order Cheilostomata BusK, 1852

Recent, Arctic Ocean to Massachusetts andCapo Cod, and on Pacific coast to Puget
Sound
Recent, Cosmopolitan (tidal zone to 223m).
Miocene of France
Recent, San Benito Island (126m). Mioceneof New Zealand
Recent, Cosmopolitan (shore to 162m). Miocene of Florida, Maryland and North Carolina. Pleistocene of California and Chiba
Recent of Queensland, Australia
Recent, Pacific coast of California and Queen
Charlotte Island, Japan Sea (151m). Pleistocene of California and Chiba
Recent, Cara Sea to Greenland, and Alaska(33m)
Recent, Greenland, Iceland, and Alaska (46m}
Recent, Alaska (33-51 m)
Recent, Pacific, north of southern California,
Atlantic coast as far south as Cape Cod(shallow water to 110m)
Eocene of North Carolina and Mississippi.
Oligocene of Alabama

Family Calloporidae NORMAN, 1903
Genus Callopora GRAY, 1848
Callopora corniculifera (HINCKS), 1884
Pl. 35, fig. 91923. ? Cauloramphus triangularis CANU and'BASSLER, p. 48, pl. 33, figs. 14-16.
1950. Callopora corniculijera (HINCKs);
OSBURN, p. 66, pl. 7, fig. 1.
1957. Callopora corniculifera (HINCKS);SouLE and DuFF, p. 94.

Description: Zoarium encrusting shellfragments. Zooecia ovate, distal partslightly rounded. Gymnocyst as muchas one-third of zooecial length, cryptocyst narrow, descending, delicately crenated. Opecia oval, narrower at distal
end. Spines usually 7 to 8 on each sideof mural rim. Avicularia minute, sessile, on outer side of mural rim. Ovicell
hyperstomial, prominent, globular, and320

Tomoko HAYAMI
Pl. 35, fig. 10

smooth.

Affinities: The present specimen resembles C. corniculifera, but can be distinguished from it by the smaller measurements.
Measurements (in mm):
Zooecia; Lz = 0.44
Wz=0.32
Ovicell; hov = 0.20
WOV=0.26
Opecia; lop= 0.20-0.28
wop=0.16

Depository: IGPS* col!. cat. no. 8672L
Callopora aurita (HINCKS), 1877
Pl. 35, fig. 15
1920. Callopora aurita (HrNcKs) ; CANU andBASSLER, p. 152, pl. 29, fig. 2.
1950. Callopora aurita (HINCKs) ; OsBURN,
p. 65, pl. 7, fig. 2.

Description: Zoarium encrusts shellfragments. Zooecia distinct, ovate, narrower with distal part; walls high and·strongly calcified. Gymnocyst small, lessthan one-third zooecial length. Spines
usually two on each side, but occasionally wanting. Avicularia present oneach side of operculum, sessile; ovicell
hyperstomial, rounded, more or lessimmersed, with one pair of avicularia,
but usually wanting.
J\!feasurements (in mm):
Zooecia; Lz=0.60
Wz=0.52
Ovicell; hov =0.12
WOV=0.10
Opecia; lop =0.44
wop=0.32

Depository: IGPS col!. cat. no. 86772.
Callopora cf. whiteavesi NORMAN, 1903
IGPS* =abbreviation for Institute of Geology
and Paleontology, Tohoku University, Sendai.

1950. Callopora whiteavesi NoRMAN; OsBURN,
p. 70, pl. 6, fig. 6.

Description: Zoarium encrusts shellfragments. Zooecia distinct, separated
by deep furrow, elongated ovate; gymnocyst developed, smooth. Mural rim
broad, bearing 6 to 7 spines at eachside, small ovate, prominent at distal
part. Septulae wanting. Dietellae threeat each distal side wall. Ovicell hyperstomial, globular, prominent, smooth,with triangular area at front.
Measurements (in mm) :Zooecia; Lz=0.52
Wz=0.32
Ovicell; hov = 0.22
WOV=0.24
Opecia; lop=0.38
wop=0.20

Depository: IGPS col!. cat. no. 86723.
Affinities: The present specimen resembles C. whiteavesi in measurements,
zooecial shape etc., but is distinguishable therefrom by the presence of avicularia.
Genus Crassimarginatella CANU, 1900

Crassimarginatella kumatae(OKADA), 1923
Pl. 35, fig. 21
1923. Membranipora kumatae OKADA, p. 223,
figs. 19, 20.
1926. Crassimarginatella kumatae (OKADA) ;HARMER, p. 224.
1958. Crassimarginatella kumatae (OKADA) ;ANDROSOV A, p. 105, fig. 14.
1965. Crassimarginatella kumatae (OKADA) ;MAWATARI, p. 602, fig. 55a.

Description: Zoarium incrusts shellfragments. Zooecia distinct. Opecia
oval or somewhat angular; mural rim
slightly elevate, without spines. Gym-

569.

Miocene Bryozoa from Hokkaido

nocyst small and smooth. Walls high,and calcified. Septulae and dietellae
wanting. Interzooecial avicularium alittle smaller than ovicelled zooecianon-ovicelled zooecia rare-, elliptical,
with a pivot, mural rim of avicularia
elevated from zooecia gymnocyst andseparated from surrounding zooecia bya shallow furrow. Ovicell hyperstomial,
globular, very prominent, granular.
Measurements (in mm) :Zooecia;
Ovicell;
Opecia;Lz=0.38Wz=0.32
hov=0.22
WOV=0.32
lop= 0.32-0.34
wop=0.22-0.24

Interzooecial
avicularium; lav=0.28
wav=0.24

Depository:

IGPS coli. cat. no. 86724.

Pyrulella corbula (HINCKS), 1880
Pl. 35, fig. 11
1926. Pyaulella corbula (HINCKs); HARMER,
p. 225, pl. 14, fig. 4.
1929. Pyrulella pyrula HINCKS, variety; CANU
and BASSLER, p. 100, pl. 5, fig. 11.
1935a. Pyrulella corbula (HINCKS); SAKAKURA, p. 7, pl. 1, fig. 4.
1952. Crassimarginatella corbula (HINCKS) ;BROWN, p. 55, fig. 112.
1960a. Crassimarginatella corbula (HINCKS) ;KATAOKA, p. 230, pl. XXVI, fig. 8.
1965. Pyrulella corbula (HINCKS); MAWATARI, p. 601, text-figs. 53a, b.

Description: Zoarium jncrusts shellfragments. Zooecia distinct, separated
by a furrow. Opecium oval. Gymnocyst developed, about one-third of zooecium length. Cryptocyst rather broad.
Mural rim with 5 or 4 spines on eachside. Avicularia and septulae wanting.
Dietellae present.· .Ovicell hyperstoinial,
prominent, large, smooth.

321

Measurements (in mm):
Zooecia; Lz=0.68
Wz=0.62
Ovicell; hov=0.24
WOV=0.24
Opecia ; lop= 0.32
wop=0.24

Depository:

IGPS coli. cat. no. 86725.

Genus Membraniporidra CANU
and BASSLER, 1917
Membraniporidra sp. A.
Pl. 35, fig. 20

Descriptio1i: Zoarium incrusts shellfragments. Zooecia distinct, separated
by a furrow. Gymnocyst small. Opecia oval or elongated. No dietellae, nospines. One septulum present in distal
wall. No avicularia. Ovicell hyperstomial, large and prominent, smooth.
Measurements (in mm) :Zooecia; Lz=0.62-0.80
Wz=0.40-0.56
Ovicell; hov=0.28
wov = 0.40-0.48
Opecia; lop=0.40-0.60
wop= 0.32-0.36

Depository : IGPS coli. cat. no. 86772.
Affinities : The present specimen resembles M. porosa OSBURN, 1950, butdiffers from it by the smaller measurements.

Genus Tegella LEVINSEN, 1909
Tegella aquilirostris (O'DONOGHUE), 1923
Pl. 35, fig. 23
1950. Tegella aquilirostris
OSBURN, p. 83.

(O'DONOGHUE) ;Description: Zoarium incrusts shellfragments. Zooecia distinct. Gymnocyst vestigial or wanting. Opecia oval;

322

Tomoko HAYAMI

mural rim very narrow, bearing one
pair spines at distal part. Ovicell hyperstomial, triangular in shape. Septulae present. Dietellae wanting.
Depository: IGPS coli. cat. no. 86773.
Tegella robertsonae O'DONOGHUE

and O'DONOGHUE, 1926
Pl. 35, fig. 22
1935a. Tegella robertsoni O•DoNOGHUE andO'DONOGHUE; SAKAKURA,. p. 8, pl. 1,
fig. 5.
1950. Tegella robertsonae O•DoNOGHUE; OsBURN, p. 81, pl. 9, fig. 5.
1957. Tegella robertsonae (O'DONOGHUE andO•DoNOGHUE); SouLE and DUFF, p.
95.

Description: Zoarium incrusts shellfragments. Zooecia distinct, separated
by a shallow furrow. Gymnocyst vestigial or wanting. Cryptocyst very smalland heavy crenated. Mural rim rather
broad, bearing one to 3 spines on eachside. Especially distal one pair ofspines stout. Two septulae present atlateral wall. Dietellae wanting. Avicularia paired, one very large, sharp
triangular, other small and sometimes
wanting. Ovicell hyperstomial at distal
part of zooecia.
Measurements (in mm):
Zooecia; Lz=0.66
Wz=0.36-0.38
Opecia; lop=0.34-0.40
wop= 0.24-0.32

Depository: IGPS coil. cat. no. 86774.
Remarks: OsBURN's quoting of theauthor of this species seems· to be atypographical error for O'DONOGHUE andO'DONOGHUE.
Tegella unicornis (FLEMING}, 1828
Pl. 35, fig. 18

1935b. Tegella unicornis (FLEMING) ; SAKAKURA, p. 107.
1936. Tegella unicornis (FLEMING) ; OsBURN.
p. 541.
1950. Tegella unicornis (FLEMING) ; OsBURN,.
p. 78, pl. 9, fig. 2.
1965. Tegella unicornis (FLEMING); MAW AT ARI, p. 601, fig. 52a.

Description: Zoarium incrusts shellfragments.
Zooecia distinct, ovate,separated by a furrow. Gymnocyst
almost wanting. Mural rim rather
broad, bearing one or two paired spines
at distal end ; more anterior pair small,often wanting. Avicularium very large
at distal end. Ovicell hyperstomial,prominent, with triangular rib in front.
Septulae wanting.
Measurements (in mm) :Zooecia; Lz=0.92
Wz=0.68
Opecia; lop=0.52
wop=0.48

Depository: IGPS coli. cat. no. 86775.

Family Hincksinidae CANU
and BASSLER, 1927
Genus Hincksina NORMAN, 1903
Hincksina cf. periporosa CANU

and BASSLER, 1928
Pl. 35, fig. 14
1928. Hincksina periporosa CA!'w and BAssLER, p. 22, pl. 2, figs. 8-11.

Description: Zoarium incrusts shellfragments. Zooecia distinct, separated
by a deep furrow, surrounded by a line·of interjunctural pores, oval. Gymnocyst smaii, smooth. Mural rim verythin and bears 4 to 5 spines on eachside. Septulae and dietellae wanting.
No avicularia.
Ovicell hyperstomial.

569.

Miocen-e Bryozoa from Hokkaido~mall.

There are pyriform zooeciules
between the zooecia; their appe~rance
i_s sporadic.
Measurements (in rom):
Zooecia; ~z = 0.44
Wz=0.30
Opecia ; lop= 0.34
wop=0.16

Depository:

IGPS coli. cat. no. 86776.

Genus Ellisina NORMAN, 1903
Ellisina levata (HINCKS), 1882
Pl. 35, fig. 81933. Ellisinidra levata HINCKS; .CANU andBASSLER, p. 19.
1950. Ellisina levata (HINCKS) ; OsBURN, p.
50, pl. 4, fig. 4.

Description: · Zoarium incrusts shellfragments. Zooecia distinct, separated
by a furrow, ovate, a little elongate.
Mural rim narrow, not bearing spines.
Gymnocyst small. Septulae and dietellae both present. Interzooecial avicul.;ir.ia small, triangular. Ovicell hyperstomial, prominent, smooth.
Affinities: The J?resent specimens resembles E. brevis CANU and BASSLER,
1920, but differs from it in the smaller
measurements.
Measurements (in rom) :Zooecia; Lz=0.44
Wz=0.32
Ovicell; hov=0.18·wov=0.20
Ope cia ; lop= 0.36
wop=0.30

Depository:

IGPS coli. cat. no. 86777.

Genus Cauloramphus NORMAN, 1903
Cauloramphus ? sp.
Pl. 35, fig. 17

DescriptiorJ,: · Zoarium incrusts shell

323

fragments. Zooecia distinct, separ~ted
by deep grooves, and pores. Opecia
ovate, narrower at distal part. Muralrim rather broad, bearing 1 t? .6 spines
on each side. Gymnocyst small, vestigial. Septulae and dietellae both present. No avicularia.
Affinities: The present .specimen is
ill-preserved, and no avicularia are seen,
thus the doubts whether the present
specimens belong to Cauloramphus.
Measurements (in rom):
Zooecia ; Lz = 0.68-0.76
Wz=0.46-0.56
Opecia ; lop= 0.52-0.58
wop= 0.28-0.40

Depository : IGPS coli. cat. no. 86778.

Family Onychocellidae ]ULLIEN, 1881
Genus Onychocella, ]ULLIEN, 1882
Onychocella subsymmetrica CANU

and BASSLER, 1929
Pl. 36, fig. 18
1929. Onychocella subsymmetrica CANU .and
BASSLER, p. 124, pl. 12, figs. 7, 8,
text-fig. 30.
1935a. Onychocella subsymmetrica CANU andBASSLER ; SAKAKURA, p. 10, pl. II,
fig. 1.
1960a. Onychocella subsymmetrica .CANU andBASSLER; KATAOKA, .p. 233, pl.
XXVIII, fig. 3.
1965. Onychocelra subsymmetrica CANU and
BAssLER; MA:WATARI, p._ 603, textfigs. 59c, d.

Description: Zoarium incrusts ~?h.el~fragments, unilamellar or b_i~amel~~r.
Zooecia distinct, united at their ~.ur~rilll, hexagonal. Mural rim thic,k ;lfl]._Q.
salient. Cryptocyst flat and d_e,ep, gran;11lar; shorter than opecium. Ope,C;iu~semielliptical, very close to rp1,1-ra~ ri!!f ;proximal border som_ewh.at ,co11caye.

Tomoko HA, YAM I

324

Onychocellarium narrow and elongate,
a little longer than zooecia length.
Measurements (in mm):
Zooecia;

Lz=0.48Wz=0.40
Opecia;lbp=0.20-0.28
wop= o:20-0.24
Onychocellarium; Lon= 0.65
Won=0,36
Opecia of
onychocellaril.J.m; hoo=0)6-0.14
W00=0.08

Depository:

IGPS coil. cat. no. 86779.

Family Microporidae HINCKS, 1880
Genus Micropora GRAY, 1848

aperture, punctured by two small opeciulae. Cymnocyst very narrow or
wanting. Avicularia and ovicell not
found.
Measurements (in mm):
Zooecia;

Lz=0.56Wz=0.44
Aperture; hap= 0.12
wap=0.20

Depository: IGPS coli. cat. no. 86780.
Remarks: Micropora coriacea ascribedto the authorship of EsPER and so usedby many previous authors, should bechanged to jOHNSTON, because ESPER'S
original Flustra coriacea represents a
species different from the present one,as pointed out by BROWN (1952, p. 126).

Micropora coriacea (JOHNSTON), 1847
Pl. 36, fig. 19
1923. Micropora coriacea EsPER; CANU andBASSLER, p. -58.
1927. Micropore coriacea (EsPER) ; CANU andBASSLER, p. 7, pl. 1, fig. 6.
1935a. Micropora coriacea (EsPER) ; SAKA·
KURA, p. 11, pl. 2, fig. 8.
1952. Micropora coriacea (EsPER) ; OsBURN,
p. 105, pl. 11, fig. 3.
1952. Micropora coriacea (JoHNSTON); MAWATARI, p. 274, text-fig. 9.
1952. Micropora coriacea (JoHNSTON);
BROWN, p. 126, text-fig. 74.
1960b. Micropora coriacea (EsPER); KATAOKA, p. 396.
1965. Micropora coriacea (JoHNSTON); MAw AT ARI, p. 603, text-fig. 61a.

Description: Zoarium incrusts shellfragments, bilamellar or unilamellar.
Zooecia distinct, separated by salient,
thickened walls, hexagonal or diamondshaped, arranged quincuncially in aradiating mosaic fashion.
Aperture
semicircular, situated at distal extremityof zooecium, its proximal lip straight,
Frontal cryptocyst granulated, depress'
ed, rising sharply at proximal lip ofGenus Verminaria ]ULLIEN, 1888
V erminaria areolae SAKAKURA, 1935
Pl. 35, fig. 41935a. Verminaria areolae SAKAKURA, p. '12,
pl. II, fig. 5, text-fig. 3.
1936. Microporina areolae (SAKAKURA); SAKAKURA, p. 264.

Description: Zoarium incrusts shellfragments or stones. Zooecia distinct,
elongated oblong, separated by a furrow.
Frontal cryptocyst, depressed,
almost flat, finely granulated; perforated marginally by a few areolar poresand two opeciules. Aperture transverse,
semielliptical with straight proximal
border. Peristome rather thin andsmooth. Avicularium ellipticaL withpivot and above aperture.
Measurements (in mm):
Zooecia;

Lz=0.88Wz=0.40
Aperture; hap=0.08
wap=0.16

Depository: IGPS coli. cat. no. 86781.
Remarks: Being provided with many

569.

Miocene Bryozoa from Hokkaido

Dpeciules, SAKAKURA placed this species
in Verminaria (1935a), but later (1936)
he transfered it to Microporina, because·of the presence of avicularia and thewanting of ovicell. But according to
the writer's interpretation of Microporina, the genus is characterized byhaving "zoarium erect, jointed segments". Thus, she is in doubt whether
the present specimen which is identicalwith SAKAKURA's areolae, can be placedin Microporina, and at present retains
it in the genus Verminaria.
Genus Microporina LEVINSEN, 1909

Microporina articulata (FABRICIUS), 1828
Pl. 35, figs. 1, 2
1929. Microporina japonica CANU and BAssLER, p. 139, pl. 14, figs. 9-11.
1936. Microporina articulata (FABRICIUs);
SAKAKURA, pp. 259-267, pl. 15, figs.
1-9.
1956. Microporina articulata (FABRICir.;s);MAWATARI, p. 120.
1958. Microporina articulata (FABRICIUS);
ANDROSOV A, p. 125.
1965. Microporina articulata (FABRICIUs);
MAWATARI, p. 603, figs. 62a, b.

Description: Zoarium erect, cylindrical, of jointed segments, branching
formed of 10 rows of zooecia. Zooecia
large, elongate; frontal almost covering
thick ectocyst. Porous cryptocyst underectocyst. These pores fill the whole
front almost to operculum. Aperturenearly semicircular; distal to aperture;
an oval avicularium. No ovicell.
Measurements (in mm):
Zooecia;

Lz =0.88-1.32
Wz=0.36
Aperture; hap =0.12
wap=0.22

Depository: IGPS coli. cat. no. 86782.

325

Family Aspidostomatidae ]ULLIEN, 1888
Genus Monoporella HINCKS, 1881

Monoporella ji.mbriata CANU
an9 BASSLER, 1927
Pl. 36, fig. 16"

1927. Monoporella fi11J.bria,ta CANU and BAssLER, p. 4, pl. J., fig. 2:
1929. Monopo;ell~1 fimbriata CANU and BASSLER;'· CANU 'and BASSLER, p. 156,. pl.
17, figs. 6-11.
1935a. Monoporella fimbriata CANU and BAss. LER; SAK.AKURA, p. 15, pl. IV, fig. 1.
1960a. Monoporella fimbriata CANU and BAssLER; KATAOKA, p. 239, pl. XXXV, fig.
10.

Description: Zoarium incrusts shellfragments. Zooecia distinct, separated
by a furrow, very large hexagonal.
Front, with cryptocyst, shallow, convex,
sometimes carinated, cover with tremopores and with granules; ·mural rim
salient, thick, round, growing thin towards base; proximal border straightand bearing two small lateral indentations. Ovicell very large, prominent,
globular, smooth, buried in distal zooecium, surrounded by costules.
Measurements (in mm) :Zooecia;

Lz=0.92-l.l2
Wz=0.68-0.72
Aperture; hap=0.12
wap=0.20

Depository: IGPS coli. cat. no. 86783_
Family Cellariidae HINCKS, 1880
Genus Cellaria ELLIS andSOLANDER, 1786

Cellaria dijfusa ROBERTSON, 1905
Pl. 35, fig. 16
1923. Cellaria fissurifera CANU and BASSLER,

Tomoko HAY AM I

326

p. 85, pl. 34, figs. 15-18.
1950. Cellaria diffusa RoBERTSON; OsBURN,
p. 117, pl. 12, fig. 9.
1957. Cellaria diffusa RoBERTSON; SouLE
and DUFF,
101.

p.

Description: Zoarium free, cylindrical,
articulated, segment. Internode long,
formed of 15 or 16 rows of zooecia.
Zooecia separated by a slight prominent wall, of elongatehexag9nal .shape.
Aperture semilunar, surrounded by athin peristome and a pair of teeth ofproximal margin .of aperture. .Cryptocyst fiat. Avicularium almost as large
as ordinary zooecium or sometimes
larger than zooecium, its opecium somewhat round. Ovicell endotoichal, covered by a lamella, convex and transverse, presents at distal mar~in.
Measure.ments (in mm):
Zooecia;

Lz=0.50Wz=0.28
Aperture; hap=0.10
wap=0.16

Depository: IGPS .col!. cat. no. 86784.

Family Cribrilinidae HINCKS, 1880
Genus Figularia ]ULLIEN, 1886
Figularia cf. carinata (WATERS), 1923
Pl. 35, figs. 3, 19
1952. Figularia carinata (W ATHRS); BROWN,
p. 185, text-figs. 129, 130.

Description : Zoarium incrusts shellfragments. Zooecia hexagonal or ovate.
Frontal shield formed of 4 to 5 pairsof costae; lacunar pores rounded. Aperture rough quadrangular. No oral
spines, no dietellae. Avicularium interzooecial, spatulate, with pivot, almost
as large as zooecial length. Ovicell
hyperstomial, rounded, prominent, andwith two oeciopores on frontal.
Measurements (in mm) :Zooecia;
Aperture;

Lz=0.42Wz=0.40
hap= 0.10
wap=0.20

In terzooecial
avicularium; hav=0.48
wav=0.16

Affinities : The present specimen re~sembles F. carinata, but differs from itin the presence of large interzooecial
avicularium, and by the lar~er ,measur.ements.
Depository: IGPS q>ll. cat. no. 86785,
Figularia crassicostulata CANV

and BASSLER, 1920
. Pl. 36, fig. 12
1920. Figularia ( ?) crassicostulata CANU andBASSLER, p. 316, pl. 43, fig. 9.

Description: Zoarium incrusts shellfragments. Zooecia distinct. Frontal
shield formed of 7 to 8 pairs of costae_
Lacunar pores rounded and large, 5 to
6 on one line. No avicularia, ovicell,.
dietellae, or spines.
Measurements (in mm) :Zooecia;

Lz=0.68
Wz=0.40
Aperture; hap=0.06
wap=0.16

Depository:

IGPS col!. cat. no. 86786_

Genus ]ullienula BASSLER, 1953
]ullienula sp~ A.
Pl. 35, figs. 12, 13

Description: Zoarium encrusts sheli
fragments. Zooecia large, and furrow
distinct, deep. .Frontal of 7 to 8 pairs.
of costae. Lacunar pores slit-like, 6 to
8 on one line. No dietellae. Ovicell not
found.
Apertur:e inverted, lyriform,.
without oral spines; proximal border

569.

Miocene Bryozoa from Hokkaido

almost straight, cardelles present. Interzooecial avicularium large and sporadic.
Measurements (in mm) :Zooecia;

Lz=0.92
Wz=0.56
Aperture; hap=0.20
wap=0.18

Depository : IGPS coli. cat. no. 86787.
Remarks: This and next species may
represent undescribed forms, but naming
is avoided at present because of thelack of specimens for a comparative
study.

327

Description : Zoarium encrusts shellfragments. Zooecia moderately large
and distinct, separated by deep grooves.
Frontal arched, formed of 5 to 6 pairsof costae. Apertural bar almost cylindrical shaped. No avicularia, ovicell,spines, or dietellae.
Measurements (in mm) :Zooecia; Lz=0.80
Wz=0.60

Affinities : The present specimen resembles M. bicornis, but differs from it
in being larger in measurements.
Depository : IGPS coli. cat. no. 86789.

]ullienula sp. B.
Pl. 35, fig. 7

Description :Zoarium encrusts shellfragments. Zooecia distinct. Frontalof 4 or 5 pairs of costae ; apertural bar
stout, very thick, triangular on eachside. Lacunar pores obscured, lumen
pores large and clear, 1-2 on one costae.
Aperture inverted, lyriform, without
oral spines ; proximal border ~!moststraight and cardelles present. Hyperstomial ovicell surrounded with slit-likepores. A vicularia not seen.
Measurements (in mm):
Zooecia;

Lz = 0.60
Wz=0.40
Ovicell; hov=0.36
WOV=0.28
Aperture; hap=0.12
wap=0.12

Depository: IGPS coli. cat. no. 86788.

Genus Reginella ]ULLIEN, 1886

Reginella nitida OSBURN, 1950
Pl. 36, fig. 91950. Reginella nitida OsBURl\', p. 181, pl. 28,
fig. 1.

Description : Zoarium incrusts shellfragments. Zooecia moderately large,
distinct. Frontal formed of 6 to 8 pairsof costae. Lacunar pores rounded andlarge, 6 on one line. No spines, no avicularia and no dietellae. Ovicell hyperstomial and large. Proximal border ofaperture thick. Aperture semicircular.
Measurements (in mm) :Zooecia;

Lz=0.64Wz=0.40-0.48
Ovicell; hov=0.36
WOV=0.36
Aperture; hap=0.08-0.10
wap=0.20

Genus Membraniporella SMITT, 1873

Depository: IGPS coli. cat. no. 86790.

Membraniporella cf. bicornis CANU

Genus Puellina ]ULLIEN, 1886

and LECOINTRE, 1927

Puellina setosa (WATERS), 1899
Pl. 36, fig. 17
Pl. 35, fig. 51927. Membraniporella bicornis CANU andLECOINTRE, p.. 25, pl. VII, fig. 1.

1950 Puellina setosa (WATERs); OsBURN, p.

Tomoko HAYAMI

328
186,::pl. 29, fig. 4.

Description: Zoarium incrusts shellfragments. Zooecia small, but withmuch variation, shorter than zooecia
but may be as broad as long, theirinflated costate areas cause ~hem toappear very distinct. Mural rim bearing 6 to 8 spines; their lateral pairs
stout. No avicularia. Ovicell hyperstomial and center of it very prominent. Dietellae and septulae both present.
. Measurements (in mm):
Lz = 0.44
Wz=0.32·
Ovicell; hov=0.16
WOV=0.28
Aperture; hap=0.04
wap=0.08

short. No avicularia.
Measurements (in mm):
Zooecia ; Lz = 0.40
Wz=0.24
Ovicell; hov=0.24
WOV=0.18

Depository : IGPS coll. cat. no. 86792.

Family l,Jmbonulidae CANU, 1904
Genus Umbonula HINCKS, 1880
Umbonula arctica (SARS), 1851
Pl. 36, fig. 13

Zooecia ;Depository:

IGPS coll. cat. no. 86791.

Family Hippothoidae LEVINSEN, 1909
Genus Hippothoa LAMOUROUX, 1821
Hippothoa flagellum MANZONI, 1870
Pl. 35, fig. 61929. Hippothoa flagellum MANZONI; CANU
and BASSLER, p. 247, pl. 22, fig. 7.
1935a. Hippothoa flagellum MANZONI; SAKAKUR.A, p. 18.
1935b. Hippothoa flagellum MANZONI ; SAKAKURA, p. 110.
1952. Hippothoa dis tans MACGILLIVRAY;
BROWN, p. 203, text-fig. 142.
1952. Hippothoa flagellum MANZONI; OsBURN,
p. 278, pl. 30, figs. 7, 8.
1965. Hippothoa dis tans MAcGILLIVRAY;
MAWATARI, p. 612, text-figs. 92a-c.

Description : Zoarium incrusts shellfragments, or other bryozoa; uniserial,with lateral branches. Zooecia elongate
ovate, without dorsal expansion; aperture ovate, with a round sinus in theproximal border. Ovicell hyperstomial,

1933. Discopora · pavonella ALDER; OKADA,
p. 215.
1952. Umbonula arctica (SARS) ; OsBURN, p.
299, pl. 36, fig. 6.
1956. Umbonula arctica (SARs); MAWATARI,
p. 124.
1958. Umbonula arctica (SARS): ANDROSOVA,
p. 167, text-fig. 97.

Description: Zoarium incrusts shellfragments. Zooecia roughly quadrangular ; front~l area nearly flat, with arow of areolae pores. Aperture rather
straight on proximal border; peristome
thin, sometimes scarcely visible ; on theproximal border where it projects forward as a short, broad mucro. Bothsides of aperture with oval avicularium,very slightly elevated. No ovicell, oral
spines, or cardelles.
Measurements (in mm) :Zooecia;

Lz=0.56Wz=0.44
Aperture; hap=0.12
wap=0.16

Depository : IGPS coll. cat. no. 86793.

Family Schizoporellidae ]ULLIEN, 1903
Genus Dakaria ]ULLIEN, 1903
Dakaria subtorquata (D'ORBIGNY), 1852

569.

Miocene Bryozoa from Hokkaido

Pl. 36, fig. 8
1895.• Smittia (Watersipora) cucullata (BusK);
NEVIANI, p. 120, Tav. VI, fig. 5.
1930. Pachycleithonia nigra CANU and BASS·
LER, p. 25, pl. 4, figs. 9-13.
1952. Watersipora cucullata (BusK); OsBURN,
p. 472, pl. 56, figs. 1-5.
1957. Dakaria subovoidea (D'0RBIGNY) ; HAR·).o!ER, p. 1022, pl. LXIX, figs. 11, 12, 14,
text-fig. 111. ·1965. Dakaria subovoidea (D'0RBIGNY) ; MAWATARI, p. 617, text-figs. 115a-c.
1967. Dakaria subtorquata (D'0RBIGNY);WEISBORD, p. 68, pl. 10, fig. 1.

Description : Zoarium incrusts shellfragments. Zooecia distinct very shallow furrow, rather regular in form.
Front regularly rounded, tremocyst
smooth with numerous large pores.
Aperture large and varies in its proportions. Peristome very thick, typically simple and slightly elevated. No
oral spines, no avicularia. No evidenceof ovicells externally.
Measurements (in mm):
Zooecia ;Lz = 0.64
Wz=0.44
Peristome; hper=0.28
wper=0.36

Depository: IGPS coll. cat. no. 86794.

Genus Schizoporella HINCKS, 1877
" Schizoporella " scissa BROWN, 1952
Pl. 36, fig. 41952. " Schizoporella " scissa BROWN, p. 245,
figs. 178, 179.

Description : Zoarium incrusts shellfragments. Zooecia distinct, ovate orof irregular form. Frontal pleurocyst
and smooth, thin walled; mural rim
semicircular, bearing 8 to 10 spines at
distal part ; proximal rim almost straightand slit-like median sinus present proxi-329

mally. Septule and dietellae both present at distal wall. Marginal part ofzooecia, with a few large areolar. pores.
A vicularia and ovicell not found.
Measurements (in mm):
Zooecia;

Lz=0.44-0.52
Wz=0.32-0.44
Aperture; hap= 0.16
wap=0.12

Depository: IGPS coll. cat. no. 86795.

Family Microporellidae HINCKS, 1880
Genus Microporella HINCKS, 1877
Microporella cilliata (PALLAS), 1766
Pl. 36, fig. 6
1890. Microporella ciliata PALLAS; ORTMANN,
p. 38, pl. 3, fig. 5.
1895. Microporella (Fenestrulina) ciliata(PALLAS); NEVIANI, pp. 82 and 105,
Tav. V, figs. 24, 25.
1923. Microporella ciliata (PALLAS); CANU
and BASSLER, p. 118, text-figs. 20A-I.
1923. Microporella ciliata (PALLAs); OKADA,
p. 227.
1929. Microporella ciliata (PALLAS); OKADA,
p. 26, pl. II, fig. 5, text-fig. 11.
1929. Microporella ciliata (PALLAs) ; CANU
and BASSLER, p. 331, pl. 40, figs. 2-4.
1931. Microporella ciliata (PALLAS) ; PRE·
NANT, p. 2.
1934. Microporella ciliata (PALLAS); OKADA,
p. 13.
1935a. Microporella ciliata (PALLAS) ; SAKA·
KURA, p. 25.
1936. Microporella ciliata (PALLAS) ; OKADA
and MAWATARI, p. 63.
1937. Microporella ciliata (PALLAs); OKADA
and MAWATARI, P·. 440, pl. XI, fig. 1.
1949. Microporella noaillanensis VIGNEAUX,
p. 67.
1952. Microporella ciliata (PALLAS) ; BROWN,
p. 250; text-fig. 184.
1952, Microporella ciliata (PALLAS); MAWA·
TAR!, p. 241, pl. XII, fi~. 12.
l952. Microporella ciliata (PALLAs) ; OsBURN,
p. 377! pl. 44, fig. l.

330

Tomoko HA YAM I

1957. Microyorella ci'liata (PALLAs); KATAOKA, p. 146.
1957. Microporella ciliata (PALLAs); SouLE
and DUFF, p. 114.
1958. Microporella ciliata (PALLAS); ANDRO·
sov A, p. 149, text-fig. 75.
19o:J. Microporella ciliata (PALLAs); KATA·
OKA, p. 254, pl. XXXI, fig. 4.
1955. Microporella ciliata (PALLAs); LAGAAIJ
and GAuTIER, Chart.
1967. Microporella ciliata (PALLAS); WEIS·
BORD, p. 72, pl. 10, fig. 2.
1967. Microporella ciliata (PALLAs) ; RucKER,
p. 829, pl. 14, fig. F.

Description : Zoarium incrusts shell
fraiiments. Zooecia distinct, ovate or
somewhat hexagonal; front with numerous small tremopores, except whenheavily calcified. Aperture nearly semicircular, straight on proximal border.
.f\scopore lunate, situated in midline alittle proximal to aperture. A single
avicularium located at side of ascopore.
Ovi'cell' liyperstomial, globose, very
pro'mineri.t, and porous. No spines.
Measurements (in mm) :Zooecia;

Lz=0.68
Wz=0.48
Ovicell; hov=0.28
wov=0.40
Aperture;· hap=0.08
wap=0.12

Depository: IGPS coll. cat. no. 86796.
Microporella lunifera (HASWELL), 1880

on both sides of ascopore. Ascopore
semilunar. Ovicell hyperstomial, globose,rather prominent, frequently surrounded by a series of large pores, but sometimes wanting.
Measurements (in mm):
Zooecia;

Lz=0.64

Ovicell ;hov = 0.28
WOV=0.40
Aperture; hap=0.06
wap=0.10

Depository:

IGPS coll. cat. no. 86800.

Microporella sp. A.
Pl. 36, fig. 2

Description: Zoarium incrusts shellfragments. Zooecia distinct, separatedby shallow furrow, ovate, somewhat
hexagonal; front with numerous small
tremopores. Aperture roughly semicircular, or quadrangular. A single avi-.
cularium, stout, rather large, locatedat side of umbonate process. Ovicell
hyperstomial, very large, umbonate process, with many pores.
Measurements (in mm):
Zooecia ;Lz = 0.68
Wz=0.40
Aperture; hap=0.08-0.12
wap =0.12-0.18

Depository: IGPS coll. cat. no. 86801.

Pl. 36, fig. 5

Family Eurystomellidae LEVINSEN, 1909

1957. Microporella lurtifera (HAsWELL) ; HAR·
MER·, p. 965, pl. LXII, fig. 34.

Genus Eurystomella LEVINSEN, 1909

Zoarium incrusts shellfragments. Zooecia distinct, separated
by a shallow furrow, elongate ovate;froht heavily calcified, tremopores sometimes visible. Aperture semicircular;
proX'imal border straight. One pair of.
avicularia, small, not elevated, locatedEurystomella bilabiata (HINCKS), 1884

Description :Pl. 36, fig. 31923. Eurystomella bilabiata (HINCKS); CANU
and BASSLER, p. 142, pl. 37, fig. 6.
1935a. Eurystomella bilabiata (HINCKs) ; SAKAKURA, p. 25, text-fig. 7.
1952. Eurystomella bilabiata (HINCKS) ; M~-569.

Miocene B'tyozoa from Hokkaido

WATARI, p. 280.
1952. Eurystomella bilabiata (HINCKs) ; OsBURN, p. 389, pl. 58, fig. 5.
1957. Eurystomella bilabiata (HrNcKs); SouLE
and DuFF, p. 118.
1960b. Eurystomella bilabiata (HrNcKs) ; KATAOKA, p. 396, pl. 41, fig. 3.

Description: Zoarium encrusts shellfragments. Zooeda distinct, separated
by furrow, roughly quadrangular, broad
and rounded distally, narrowed andtruncated at proximal end; front notheavily calcified, without pores, often
rising into a broad low umbo. Aperture hat-shaped with a very narrow
brim, rounded distally and becoming
abruptly wider near almost straightproximal border.
No avicularia, nospines. Ovicell hyperstomial.
· Msasurements (in mm) :Zooecia ;Lz = 0.68
Wz=0.48
Aperture; hap= 0.16
wap=0.24

Depository: IGPS coll. cat. no. 86802.

Family Mucronellidae LEVINSEN, 1902
Genus Mucronella HINCKS, 1880
Mucronella Labia,ta (LEVINSEN), 1886
Pl. 36, figs. 10, 20
1952. Mucronella labiata (LEVINSEN) ; OsBURN, p. 437, pl. 52, figs. 1, 2.

Description: Zoarium encrusts shellfragments.
Zooecia large, elongate
quadrangular, distinct, separated bydeep furrow; frontal densely and minutely granulated, with one to two rowsof small lateral pores·. Aperture roughly semicircular, proximal border straightwith a broad, short lyrula. Peristome
high, proximal. Ovicell hyperstomial,large; hemispherical, distal end often

331

sloped downward toward base of succeeding zooecium. Spines not found.
Measurements (in mm):
Zooecia ;Lz = 0.80-0.88
Wz=0.44
Ovicell ; hov = 0.30
WOV=0.40
Aperture; hap=0.24
wap"=0.28

Depository:

IGPS coli. cat. no. 86803.

Genus Parasmittina OSBURN, 1952
Parasmittina sp. A.
Pl. 36, fig. 7

Description: Zoarium encrusts shellfragments. Zooecia distinct, with shalpleurocyst withlow furrow; frontal
a row of areolar pores ; peristome high,forming tube in ovicelled zooecia. One
to three avicularia present at proximal
border of peristome. Distal part ofaperture bearing 4 spines. Ovicell hyperstomial, prominent, perforated bynumerous pores.
Measurements (in mm):a

Zooecia;

Lz=0.52Wz=0.36
Peristome; lper=0.24
wper=0.24

Affinities : The present spec1men resembles P. alaskensis OsBURN, 1952, butdiffers from it in the presence of fourspines.
Depository: IGPS coil. cat. no. 86806.

Genus Parella GRAY, 1848
Porella acutirostris SMITT, 1867
Pl. 36, fig. 15 .
1936. ?orella acutirostris SMITT; OsBURN, p.
542.
1952. ?orella acutirostris SMrTT; OsBuRN, p.
394, pl. 46, fig. 4.

Tomoko HAYAMI

332

1956. Parella acutirastris SMITT; MAWATARI,
p. 129, fig. lOh-k.
1958. Parella acutirastris SMITT; ANDROsov A, p. 163, text-fig. 93.

Description: Zoarium encrusts shellfragments. Zooecia distinct, hexagonal
or oval, separated•-'by, ·a salient thread.
Frontal slightly'~:c.on••tex, smooth, withseveral pairs of. :areolar pores in marginal portion. Aperture semicircular,rather straight· proximally, surroundedby thin, prominent peristome. Avicularium, median, subOJ;al, acute, on aprominent umbo including broad chamber. Ovicell hyperstomial.
Measuremnets (in mm) :Zooecia ;Lz = 0.48
Wz=0.28
Peristome; lper=0.16
wper=0.20

Depository : IGPS coli. cat. no. 86805.

Genus Rhamphostomella LORENZ, 1886
Rhamphostomella hincksi

NORDGAARD, 1906
Pl.. 36, fig. 1
1952. Rhamphastamella hincksi NoRDGAARD;OSBURN, p. 428, pl. 50, fig. 3.

Description : Zoarium encrusts shellfragments. Zooecia distinct, with shallow furrow; frontal somewhat inflated,smooth, with a row of conspicuous
areolar pores between which costal ribs
extend for a short distance at front.
Aperture nearly round, without either
cardelles or lyrula.
Ovicell hyperstomial, large, prominent, smooth, withseveral pores.
Measurements (in mm):
Zooecia;
Ovicell;Lz=0.60Wz=0.44
hov=0.36
WOV=0.36

Aperture; hap= 0.20
wap=0.16

Depository:

IGPS coil. cat. no. 86806,

Rhamphostomella spinigera LORENZ, 1886
Pl. 36, fig. 11
1920. Rhamphastamella spinigera LoRENZ;CANU and BASSLER, p. 476, text-figs.
134S, T.
1936. Rhamphastamella spinigera LORENZ;OsBURN, pp. 538, 542.
1952. Rhamphastamella spinigera LoRENZ;OsBURN, p. 429, pl. 51, fig. 1.

Description : The present specimen
agrees with OSBURN's description (1952).
Zoarium encrusts shell fragment. Zooecia distinct with deep separating
grooves; front
somewhat inflated,smooth; one row of marginal areolations. Aperture somewhat rounded;
proximal border bisinuate, with a cardelle at tip. Peristome thin, bearing 4
stout spines. Avicularian umbo locatedat one side ·of aperture, rarely extends
to midline of front.
Measurements (in mm):
Zooecia;

Lz=0.65Wz=0.40
Aperture ; hap= 0.18
wap=0.20

Depository: IGPS coli, cat. no. 86807.

Family Phylactellidae CANU
arid BASSLER, 1917
Genus Perigastrella CANU
and BASSLER, 1917
Perigastrella rectilineata CANU

and BASSLER, 1920
Pl. 36, fig. 14
1920. Perigastrella rectilineata CANU andBASSLER, p. 582, pl. 73, figs. 14-19.

569.

Miocene Bryozoa, from Hokkaido

Description: Zoarium encrusts shellfragments. Zooecia distinct, disposedin linear rows; frontal smooth, convex,
umbonate process. Aperture semielliptical; peristome thin, a little salient
and bearing 4 to 6 spines in distal
part. Ovicell hyperstomial, globular,smooth, and prominent, fixed in parton distal zooecium. No avicular~a.
Measurements (in mm) :Zooecia;

Lz=0.36-0.44
Wz=0.32
Aperture; hap=0.08
wap =0.08-0.10

Depository: IGPS coil. cat. no. 86808.
References
ANDROSOV A, E. I. (1958) : Bryozoa of theolder Cheilostomata of the north part of
the Japan Sea. (in Russian). Issledovaniya Dalinevostochnykh Morei V, Akademiya Nauk SSSR, pp. 90-204, 104 textfigs.
BROWN, D.A. (1952) : The Tertiary Cheilostomatous Polyzoa of New Zealand Brit.
Mus. (Nat. Hist.), Znol., pp. 1-405, 296
text-figs.
CANU, F. and BASSLER, R.S. (1920): North
American Early Tertiary Bryozoa. U.S.
Nat. Mus., Bull. 106, pp. 1-877, 162 pls.
--and-- (1923) : North American Later
Tertiary and Quarternary Bryozoa. Ibid.,
125, pp. 1-302, 47 pls.
- - and - - (1927) : Classification ·of the
Cheilostomatous Bryozoa. Proc. U.S.
Nat. Mus., vol. 69, no. 14, pp. 1-43, 1 pl.
- - and - - (1928): Fossil and Recent
Bryozoa of the Gulf of the Mexico
Region. Ibid., vol. 72, pp. 1-165, 34 pls.
- - and - - (1929) : Contributions to the
biology of the Philippine Archipelago
and adjacent regions; Bryozoa. Proc.
U.S. Nat. Mus., Bull. 100, vol. 9, pp. 1685, 94 pls.
- - and - - (1930) : ·The Bryozoan Faunaof the Galapagos Islands. Proc. U.S.
Nat. Mus., vol. 76, art. 13, pp. 1-78, 14

333

pls.
- - and - - (1933): The Bryozoan Faunaof the Vincentown Limesand. U.S. Nat.
Mus., Bull. 165, pp. 1-108, 21 pls.
- - and LECOINTRE, G. (1927) : Les Bryozoaires Cheilostomes des Faluns de Touraine et d'Anjou.
Mem. Soc. Geol.
France (N.S.), tome III, pp. 19-50, pls.
6-11.
HARMER, S.F. (1926): The Polyzoa of the
Siboga Expedition, Pt. II, pp. 24-501, pls.
XIII-XXXIV.
-.- (1957): Op. cit. Pt. IV, pp. 642-1147,
pis. XLII-LXXIV.
KANNO, S. (1962) : Molluskan fauna fromthe so-called Setana Formation, Southwestern Hokkaido, Japan.
Sci. Rep.
Tokyo Univ. Education, Sec. C, vol. 8,
no. 73, pp. 49-62.
KATAOKA, J. (1957): Bryozoa from theDaishaka Formation (Pliocene), MinamiTsugaru-Gun, Aomori Prefecture. Trans.
Proc. Paleont. Soc. japan, N.S., No. 28,
pp. 143-153, 1 pl.
- - (1960a) : Bryozoa Fauna from the"Ryukyu Limestone" of Kikai-jima, Kagoshima Prefecture, Japan. Sci. Rep.
Tohoku Univ. 2nd ser., vol. 32, no. 2,
pp. 214-272, 13 pls.
- - (1960b): Bryozo·a from Mogami-Tai,
Japan Sea. Ibid., Spec. vol., no. 4, pp.
394-399, 1 pl.
KuBOTA, K. (1950): Illustrated Cenozoic
fossils 9 (Fossil Pectinidae of Setana
series). Cenozoic Res., no. 6, pp. 12-18,
2 pls.
LAGAAIJ, R. and GAUTIER, Y.V. (1965):
Bryozoa assemblages from marine sediments of the Rhone delta, France. Micropaleontology, ·vol. 11, no. 1, pp. 39-58,
34 figs., 1 chart.
MASUDA, K. (1960) : On the Morphogenesis
of Nanaochlamys.
Sci. Rep. Tohoku
Univ. 2nd ser. Spec. vol. no. 4, pp. 371383, pl. 39, 10 text-figs.
- - and SAWADA, Y .. (1961): Some New
Tertiary Pectinids · from Southwestern
Hokkaido, Japan. . japan jour. Geol.
Geogr., vol. 32, no. 1, pp. 20-29, 1 pl.
MAWATA).H, S. (1952): Bryozoa of Kii Pe-

Tornoko HAYAMI
ninsula. Publ. Seto Mar. Bioi. Lab., II(2)' pp·. 261~288, 1 pl.
- - (1956) : Cheilostomatous Bryozoa fromthe Kurile Island and the Neighbouring
Districts. Pacific Science, vol. X, no. 2,
pp: 113-135, 15 text-figs.
- - (1965): Bryozoa; in New Illustrated
Encyclopedia of the Fauna of Japan. pp.
585-628. (in Japanese) Hokuryu-Kan.
NAGAO, T. and SASA, Y. (1934):, Recent
geological history and Cainozoic formations of the southwester'n part of Hokkaido (4). jour. Geol. Soc. japan, vol.
41, no. 488, pp. 211-216.
NEVIANI, A. (1895) : Briozoi fossili della
Fornesina e Monte Mario presso Roma.
Paleontgr. Italica I, pp. 77-140, 2 pls.

OKADA, Y. (1923): On a Collection of Bryozoa from the Straits of Corea. Annot.
Zool. Japan, vol. 10, art .. 22, pp. 215-234.
- - (1929) : Report of the Biological Surveyof Mutsu Bay, 12, Cheilostorriatous Bryozoa of Mutsu Bay. Sci. Rep. Toho~uImp. Univ., 4th Ser. Biology, vol. IV,
no. 1, pp. 11-35, 5 pls.
- - (1933) : On a Collection of Bryozoa'
from the Northern· Kurile Expedition~
Bull. Biogeogr. Soc. japan, vol. 4; ·no. 3,
pp. 213-216.
- - (1934) : Bryozoa Fauna in the Vicinityof the Shimoda Marine Biological Station. Sci. Rep. Tokyo Bunrika Daigaku,Sec. B, vol. 2, no. 26, pp. 1-20, 2 pls.
-·- and MAWATARI, S. (1936): Bryozoa

Explanation of Plate 35(All enlarged 25 times and all from the same locality)
Figs. 1, 2. Microporina articulata (FABRICIUS).
1. Porous cryptocyst under ectocyst.
2. Another zoarium covering thick ectocyst.
Figs. 3, 19. Figularia cf. carinata (WATERS).
3. Ovicelled zoarium.
19. Another non-ovicelled zoarium.
Fig. 4. Verminaria areolae SAKAKURA.
Fig. 5. Puelliria setosa (WATERS).
Fig. 6. Hippothoa fragellum MANZONI.
Fig. 7. jullienula sp: B.
Fig. 8. Ellisina levata (HINCKs).
Fig. 9. Callopora corniculifera (HINCKs).
Fig. 10. Callopora cf. whiteaves'i NORMAN.
Fig. 11. Pyrulella corbula (HINCKs).
Figs~ 12~ 13. jullienula sp. A.
13. Interzooecial avicularia shown in ,middle part.
Fig. 14. Hincksina cf. periporosa CANV and BAss·LER.
Fig. 15. Callopora aurita (HINCKS).
Fig. 16.· Cellaria diffusa RoBERTSON.
Fig; 17. Caulotamphus (?) sp. A.
Fig. 18. Tegella unicornis (FLEMING).
Fig. 20. Membraniporidra sp. A.
Fig. 21. Crassimarginatella kurriatae (OKADA).
Fig. 22; Tegella · robert'sonae O'DoNOGHUE and 0'DbNOGHUE.
Fig. 23. Tegella aquilirostris (O'DONOGHUE).

HAYAMI:

Miocene Bryozoa from Hokkaido

Photo by KUMAGAI

Plate 35

569.

Miocene Bryozoa from Hokkaido

Fauna collected by the "Misago" during
the Zoological Survey around lzu Peninsula (II). Ibid., vol. 3, no. 49, pp. 5373, 2 pis.
- - and - - (1937) : On the Collection of
Bryozoa along the Coast of Onagawa
Bay and its Vicinity, the Northern Partof Honshu, Japan. Sci. Rep. Tohoku
Imp. Univ., 4th Ser., Biology, val. 11,
no. 4, pp. 433-445, 1 pl.
ORTMANN, A. (1890): Die Japanische Bryozoenfauna. Arch. f. Naturgesch., Bd. 1,
H. 1, pp. 1-74, 4 pis.
OsBURN, R.C. (1936) : Bryozoa collected in
the American Arctic by Captain R.A.
Bartlett. jour. Washington Acad. Sci.,
vol. 26, no. 12, pp. 538-543, 1 text-fig.
- - (1950) : Bryozoa of the Pacific Coast of
America. pt. 1, Cheilostomatous-Anasca.
Allan Hancock Pacific Expedition, vol. 14,
no. 1, pp. 1-269.
- - (1952) : Op. cit. pt. 2, CheilostomatousAscophora, vol. 14, no. 2, pp. 270-611.
PRENANT, M. (1931) : Sur une collection de· · Bryozo~ires -de Ia Mer du Nord appartenant au Musee royal d•Histoire Nat.
Belgique. Bull. Mus. roy. d'Hist. Nat.
Belgique. tome _7, no. 17, pp. 1-6.
RucKER, J.B. (1967): Paleoecological analysis of Cheilostome Bryozoa from Venezuela-British Guiana shelf sediments.

ImaganeKaigarabashi
KunnuiTane-gawa

335

Bull. Marine Sci., vol. 17, pp. 787-839,
16 figs.
SAKAKURA, K. (1935a) : Pliocene and Pleistocene Bryozoa from the Boso Peninsula(I). jour. Fa c. Sci. Imp. Univ. Tokyo,
Sec. II, val. 4, pp. 1-48, 7 pis.
- - (1935b): Bryozoa from Toyama Bay,Sea of Japan. Annat. Zool. japan., vol.
15, no. 1, pp. 106-119, 1 pl., 2 text-figs.
- - (1936) : On Microporina articulata (Fabricius), a Cheilostomatous Bryozoa.
jour. Geol. Soc. japan, vol. 43, no. 15,
pp. 259-267, 1 pl.
SAWADA, Y. (1962): The geology and paleontology of the Setana and Kuromatsunai areas in southwest Hokkaido, Japan.
Mem. Muroran Inst. Tech., vol. 4, no. 1,
pp. 1-110, 13 tables, 9 text-fig., 8 pis.
SouLE, J.D. and DuFF, M.M. (1957) : Fos·sil
Bryozoa from the Pleistocene of Southern
California. Proc. Calif. Acad. Sci., 4thSer., vol. 29, no. 4, pp. 87-146.
VIGNEAUX, M. (1949) : Revision des Bryozoaires neogenes du Bassin d•Aquitaine
et essai de classification.
Mim. Soc.
Geol. France, vol. 60, pp. 1-155, 40 figs.
WEISBORD, N.E. (1967) : Some Late Cenozoic Bryozoa from Cabo Blanco, Venezuela. Bull. Amer. Paleont., vol. 53, no.
237, pp. 1-237, 12 pis.

A, ~
~~fl
~Ill tt
fj ill836

Tomoko HAYAMI

Explanation of Plate 36(All enlarged 25 times and all from the same locality)
Fig. 1. Rhamphostomella hincksi NoRDGAARD.
Fig. 2. Microporella sp. A.
Fig. 3. Eurystomella bilabiata (HINCKS).
Fig. 4. "Schizoporella" scissa BROWN.
Fig. 5. Microporella lunifera (HASWELL).
Fig. 6. Microporella ciliata (PALLAs).
Fig. 7. Parasmittina sp. A.
Fig. 8. Dakaria subtorquata (D'ORBIGNY).
Fig. 9. Reginella nitida OsBuRN.
Figs. 10, 20. Mucronella labiata LEVINSEN.
10. Ovicelled zoarium.
20. Non-ovicelled part of the same zoarium.
Fig. 11. Rhamphostomella spinigella LoRENZ.
Fig. 12. Figularia crassicostulata CANU and BASSLER.
Fig. 13. Umbo nul a arctica (SARS).
Fig. 14. Perigastrella rectilineata CANU and BASSLER.
Fig. 15. Parella acutirostris SMITT.
Fig. 16. Monoporella fimbriata CANU and BASSLER.
Fig. 17. Membraniporella cf. bicornis CANU and LECOJNTRE.
Fig. 18. Onychocella subsymmetrica CANU and BASSLER.
Fig. 19. Micropora coriacea (JoHNSTON).

HA YAM!:

Miocene Bryozoa from Hokkaido

Photo by KUMAGAI

Plate 36

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 79, pp. 337-354, pis. 37, 38, Sept. 30, 1970

570.

LOWER TRIASSIC AMMONOIDS FROM THE KIT AKAMI MASSIF*
YUJI BANDO
Department of Geology, Kagawa University~tJ:JliJ:!!li.H?mil±\ U-:~ti~:=.:\~l:*c 7 /'-=E-:T-1 1-: ~tJ:iJJJ:!!ll¥it'i~OYffi~:=.:'i!BiHJ:~t'LJ: fJ-'flil!!IW J: f) Scythian ~;fJJ)tJl~tt~-_f- 'Q Glyptophiceras.lJZT~J\l • 7ciRmO)=P!i J: fJ t.>. 'Qtf•,il;!¥:1±\ L "*-f::., :kiR~O)t=j:l$f.t)!iiJ>G Scythian f&l!ll~~T Meekoceras !l!IJ~Wt~~l±\ Lt-::o '8:!1t4Yf-icJ llll!J JHji;O):;k/RJIN C. J:{li:O) !!J.if!RIW C. O)rJEgff.t)!i:ii' Gf';J: Leiophyllites !IW~n~il;!¥:t±l L-, {-0)~5Jl:, ~tJ:LllJ:lliO)r$:=.:f]:;ljH'J: Otoceratan J: f) Prohungaritan R:..¥ 'Q -)!0)P!ii'fii;95~VCV,'Qi:.C.iJ;UJll?ii'U.J:-~t-=o~ ]!:[ tt 'm

Recently Dr. Yoshio ONUKI collected
some ammonite specimens from theshale beds at the boundary between theOsawa and Fukkoshi formations at Konori in Onagawa-cho, Ojika-gun, near
Ishinomaki City, and on the other hand,
Dr. Keiji NAKAZAWA of the Kyoto
University collected some of interesting
ammonites of the genera Meekoceras
and Eufiemingites from the calcareous
black shales of the Osawa Formation at
Hiraiso coast in Motoyoshi-cho, Motoyoshi-gun, Miyagi Prefecture.
The geological structure of the Triassic System in the Kitakami Massif israther simple compared with that ofsouthwest Japan and therefore, thestratigraphic succession of the rocks andof the ammonites can be worked out
easier than at any other locality inJapan. The writer recently reported on
the occurrence of Meekoceras and Eufiemingites from the Osawa Formationand discussed about their stratigraphic
significance (BANDO, 1968).
Up to date, the ammonoid fossils newly obtained from the Kitakami Massif
are as follow :Introduction
Only a single species of Lower Triassic ammonites, Subcolumbites cf. perrinismithi (ARTHABER), from the Kitakami Massif has been described. This
ammonite is from the upper part of
the Osawa Formation at Isatomae,
Motoyoshi-cho, Motoyoshi-gun, Miyagi
Prefecture, in the southern Kitakami
Massif. The Lower Triassic System in
the Kitakami Massif consists of two
formations, i.e. the Hiraiso in the lower and the Osawa in the upper. Fromthe stratigraphical position in the geological column the Hiraiso Formation
has been considered as the Lower Scythian and the Osawa as the Upper Scythian. Dr. Koichiro ICHIKAwA once reported on the occurrence of Ophiceras
from the Hiraiso Formation, and theammonite and stratigraphic horizon
were refered to his Tatean age ofLower Scythian age, but this ammonite
was not described.

* Received March 23, 1970; read January
20, 1970 at Sendai.

337

Yuji BANDO

338

Species
Glyptophiceras cf. gracile SPATH
Flemingites sp.
Eujlemingites sp.
Meekoceras spp.
X enoceltites ? sp.
Danubites sp.
Leiophyllites cf. pitamaha (DIENER)
Leiophyllites aff. pradyumna (DIENER)
Leiophyllites sp.
Danubites aff. ambika DIENER

Of these ammonites the genus Glyptophiceras which was firstly found fromthe Hiraiso Formation is known tooccur from the lowest horizon of the
Scythian stage, the Lower Otoceratan
or Lower Induan substage, and in Japan
it besides the Kitakami Massif is known
only from Tomisu in the Maizuru Zone,
Hyogo Prefecture. The genus Glyptophiceras originally belong to the Ophiceras fauna and was regarded as thecharacteristic ammonite of Otoceratan(SPATH, 1930, p. 30).
The biostratigraphic succession of theammonoids from the Hiraiso and Osawa
Formation is as follows:
4.
3.
2.
l.

Leiophyllites cf. pitamaha zone
Subcolumbites perrinismithi zone
Meekoceras and Eujlemingites zone
Glyptophiceras cf. gracile zone

The lithologic facies of the Hiraiso
Formation at the type locality is characterized by calcareous light green graysandstones with thin bands of argillaceous limestones and conglomerates atthe basal part and lies on the Upper
Permian Toyoma Formation which isreadily recognized by the black shale
facies in which fossils are quite rare.

1

Lower Triassic System in the
Kitakami Massif
As

alreadymentioned

above,

theFormation
Hiraiso
Osawa
Osawa
Osawa
Osawa
Osawa
Osawa
Osawa
Osawa
Osawa

Locality
Hiraiso
Osawa
Osawa
Osawa
Osawa
Osawa
Konori
Konori
Konori
KonoriLower Triassic System of the Kitakami
Massif consists of the two formations,of which the lower comprises sandstonefacies and the upper shale facies. These
formations are distributed along theeastern and western marginal parts ofthe southern Kitakami Massif, because
the general geologic .structure is a synclinolium with axis of SSW trend, thus
the Lower Triassic strata crop out
along the eastern and western parts ofthe massif and lie on the Permian Toyama Formation. At the Hiraiso coast
the Toyoma Formation ·intercalates inthe black slate facies thin bands oflimestone, -but no fossils ·have been reported from it, and is overlain by a
2-3 m thick conglomerate. In general,the Lower Triassic System is characterized by a megacyclothem commencing
from coarse sandstone and conglomeratefacies at the basal part and grading
upwards to the fine black shale facies
at the upper part.
Historically, the geological surveys of
the Triassic System in the type area
have ·been undertaken by many authors,
especially by KUROSAWA (1929) and MABUTI (1932) who discovered "Pecten "ussuricus (BITTNER), "Pecten" sichoticus(BITTNER), "Pecten" cf. discites (ScHLOTHEIM), Pecten alberti virgalensis (WITTENBURG) etc. from Tate near Isatomae,
by SHIIDA (1939) who surveyed the areaof the type locality and subdivided the570.

Lower Triassic Ammonites

1:.01
~

339

Terrace grovels[UfiiJ---;; onomori Formatio;-}

X a: G/yptopniceros)(' b: Meekoceros andEuflemingifes.
[!]]]]]] Sh~ndate
Formation

Saragai Group~~!Upper Triassic)
Is atom ae Formation·~ Fukkoshi Formation } inoi Group~

E::":: Osowa Formation(Lower and Middle

GJ 11iraiso Formation

Triassic)~ Toyoma Formation (Upper Permian I
fi'.::+:il.

t±::t:!j Gran1te~~

Dyke rocks~~

unconformity

Fig. 1. Geological map of the Hiraiso district, Motoyoshi-cho, Motoyoshi-gun, Miyagi
Prefecture, in the Kitakami Massif, with indication of the locality of Glyptophiceras andMeekoceras faunas. (Geological map after Y. ONUKI and Y. BANDO, 1959)

Triassic formations into some members.
Later INAI (1939), ICHIKAWA (1948, 1951),
ONUKI and BANDO (1958), and BANDO(1956, 1958) contributed to the stratigraphy of the type area. Especially, IcHIKAWA (1948, 1951) proposed a subdivisionof the Triassic System of the type areain the Kitakami Massif, and this became
the basis for his time stratigraphic sub-division of Japanese Triassic.
The Hiraiso Formation (ICHIKAWA,
1946) is composed of light gr·eenish calcareous sandstone with arenaceous limestone layers above the basal conglomerate in its lower part, and has yielded
many Lower Triassic pelecypods, butammonoids are very rare. The upper
part of this formation comprises ·a thin

Y~~ji BANDO

340

Formation. The boundary between the
Hiraiso and Osawa Formations is places
at the upper limit of the dark g rey finegrained sandstone.

alternation of calcareous light blue sandstone and dark gray fine sandstone,
which grades upwards into the calcareous siltstone of the next yo unger Osawa

OMAEHAM;VONAGAWA-CHO

/

~

r

!a=
KONORIX

289

0

234

2

Fig. 2. Map showing t he localit y of the L eiophyllites fa una at Konori ne ar
Onagawa-cho, Ojika-gun , Miyagi Prefe cture, in the southern K itaka mi Massif.

The Osawa Formation (ICHIK AWA , 1948)
consists of a banded alternation of wellbedded calcareous fine sandstone andsiltstone. The upper part of this for mation is composed of laminated clark
blue calcareous shales which y ielded(1)some interesting Upper Scythian am monoid as Sub co lumbites cf. perrinismithi.
This formation gradually change into
the Fukkoshi Formation (Middle Triassic) which is composed of li ght green
sandstone, banded sanely shales and(2)

Fig . 3. (1) Banded calcareous sa ndstone of the Hirai so For m a tion at Hiraiso, Motoyoshicho, Moto yoshi-gun, Mi yag i Prefecture . Glyptophiceras cf. gracile SPATH was collected fromthis formation. (2) The outcrop of black shales of the Osawa Formation at Osawa, Motoyoshi-cho, Moto yoshi-gun, Mi yag i Prefecture. The specimens of M eek oceras and Eujle mingites
were collected from here by Professo r Keiji NAKAZAWA.

570.

Lower Triassic Ammonites

conglomerates. In the uppermost part
there is a thin alternation of sandstoneand sandy shale, and some non-continuous layers of sandstone in the shale.
Up to date, the precise chronologicalhorizon ranging from the Hiraiso Formation below to the middle part of theOsawa Formation above was unknown,
but the occurrence of Glyptophiceras cf.
gracile from the Hiraiso Formation andthe Owenitan ammonites, i.e. Meekoceras
and Eujlemingites, from the Osawa Formation gave an important bright tothe solution of this problem. Glyptophiceras gracile was first described by
SPATH (1930, p. 34) from the Otoceras
and Ophiceras beds of Clavering Islandand S. S. W. of Cape Stosch in Eastern
Greenland and he placed their horizonin the lower part of Otoceratan. Later,
KuMMEL (1957) proposed the two ammonite zones, i.e. Otoceras woodwardi
in the lower and Ophiceras commune in
the upper, for the SPATH's Otoceratan
stage. The chronological subdivision
for the Lower Triassic have also been
attempted by KIP ARISOVA and POPOV(1956, 1961, 1964) and they proposed theInduan stage for the Lower Scythian as
regarding the range from the Otoceratan
to the early part of Flemingitan. Morerecent classification of the Lower Triassic is of TOZER (1965, 1967) and SrLBERLING and TOZER (1968). According
to the classification of them, the Oto<:eratan and the early part of Gyronitan
stages were regarded as the Griesbachian,and moreover, the Griesbachian was divided into the lower, which consists of
the Otoceras concavum zone in the lower
and the Otoceras boreale zone in theupper, and the upper, which consists of
the Ophiceras commune zone in the lower and the Pachyproptychites strigatuszone in the upper. It is difficult to.decide the precise horizon of japanese

341

B~

!fil2
~3

<-1}7eelroc<'ros andEufleminqites

04
~5
~6

200
M.

Glypfophiceras
Cf. gracile

1000Fig. 4. Compiled columnar section of
the Middle and Lower Triassic at Hiraiso,
Motoyoshi-cho, Motoyoshi-gun, Miyagi Prefecture, in the southern part of Kitakami
Massif, with horizons of the characteristic
ammonites. 1: black shale, 2: thin alternation of sandstone and siltstone, 3: banded
alternation of sandstone and silty shale, 4:calcareous sandstone, 5: conglomerate, and
6: unconformity.

Glyptophiceras in the above mentioned
chronological stages because the occurrence of only single specimen and noammonite beside this specimen, but
judging from the general faunal sequence of the lowest Scythian in Greenland, North America, Himalayas andin Russia the present writer correlated
the horizon with the Lower Otoceratan
stage.

.

Table l.

1\Standard ammonite ~loge Standard ammonite zone'2

Prohungarilan

~

0

-"

-;:,

0

w
:;;

u

-

c.
c.

:::J

c:J

Prohungaril es

simi/isSpat hi an

Tiroliles; r.Yasa,t:l1Jles

ArclocerasdiF!eminglles fleming/anus
Konlnckiles

I-

tordusb!oms tran·j Meekoceras

Meekoceras grac/1/lalus

Flemingilan

U.S. S. R

groct!ltotus

-"

-;,

Columbiles Zone

u

;;;

c

OwenllesZone

Dienerian0::

Gyronilan

~

w

3

w

--'

Vishnuites~
30

Otocerala n_jOph/ceras

communewoodward/----

Oweniles0,.,

Gyroniles Zone
1i; fl:Jchypr&ptycht!es
8::
sfriatus

decipiens

Otoceras

Anaslblrlles Zone
Zonec

Proplychiles rosenkrantzi

I

0

0

c.
c.

:::J

-"

Proplychiies candidus

Priono!obus rolundatus

0

Zone

Paranorlles sverdrup/

volulus

X enodlscoides tal/ax"'

Lelophyllites

Subcolumbites Zone

(f)

-"'

0

Banda (1964)
0

-Q)

~

c

Prohungar!les Zone
c

"""

Japan

Q)

Smithianii

Keyserlingiles
subrobus Ius
Nordophiceras pi/alumcasslanus

Anasiblr!les mu/1/formls
Owe ni!an

Northeast

Kiparisova8 Papaw ( 1964)

0

Cqlumbilan

(f)
(f)

<[

CanadaTozer ( 1965)

Columbites paris/anusI(f)ArcticKummel (1957).

Spalh(l930,1934)

"'0

co

Correlation table for the Lower Triassic Series based upon the characteristic ammonoids.
(complied by Y. BANDO, 1970):::J
Griesbachi- I-- Ophicerus commune
an :;; Otoceras borea/e3

Otoce10s

3

-

n.sp~

u

c

(f)

0

;;;

::>

Entollum8

Zone)c.,:"-<

3"0=-(Eumorphotis

0--'

Otoceras

Zone

~
~
0

Glyptophlceras Zone

* Otoceras concavum ToZER (ToZER, 1.967)..., s

(/)
~

Cl
('1)
l:l
(/)

~

Ill

>- s
-~

Ul

>-l

::r:

q

p::
~
......
""
tD"='-

>-

0

r.1

"'

>-- c:J
>-3

w

0

;:,-

~.

""
;;;""
I'>

'0
('1)

"rj

......

tO>--'......

::r: 3

(/)
~

::r:
>-<:

;:;·

>-<: -·>->-l '-<">-l 0
.....

>-l
">-l

('1)

......

"1

tO

0......
00
00

to '0

?

"1
.....

l:l"

Ill
no
0..
Ill
('1)

-·

0

0

(')
('1)
"1
Ill
no
Ill
(')
('1)
Ill
('1)

>--

H::::...

0'
0

w

'-<

00
.....
~

"1

!3
~
;::;·

('")
('1)

I:'

"1

Ill
no

00

::;.·

.;·

3.
('1)

~Ill

~

(')
...,

.....

c:;·

=

::r:

Ill
p.)
....;-, ~- 0
~ 0.. ~ "rj .:;;- ::<!
~ ~Ill<~ 0-·l:l no~ l:l::C~~C.&"'
0 nono "1 c 1--'• ........
l:l ('1) "1 l:l" Ill l:l ;:J "1 '-< z~~~(Jq>­('1) ('j) ~ 0.. '-< >-g.lll::;'Og (0::::!'".
rt
;:J
('
1
)
Ill
[;;
0..
~
c=:s~c::'-<>-loc;gis('j)(')
"1 "
l:l"
('1)
H->o..H;~~J
l:l" 0''0;::>:::~ ::<!
Ill 0
0 l:l" 0 ::: ('1) ~ l:l "(/l:::: rt (i)
(/l
.....
no 0~ l:l"•
no ;::p
('j)
'-<
(/l
· t-1,
(/l
l:l
·
0
~
O noro<l:lo"1 0
0 ::1.
& nol:l"('l)Q,,_,
l:l "1 0' ~"0('1)0.-.i:j~Cll~no "1 .....
::<!
('1) 0 0..
(Jq
Ill ;:J 0
MH->11>11>;2
no ~ ::1.
"1
l:l
'-<
"1
.,._ "1-·no Ill ....
Cllno('1) 0 ':7 Ill.....
;::>:::
0..
.....
l:l
0..
-·
"0
l:l"
('1)
Ill l:l""i ~ .....
l:l;:::,.. ~ -· '-< 0 ~ (/l c:: ('j) -·0.. ::: • .:;;- ~ ('1)~ 0..
::::: ;::J...... :::::1- · '(fJr t P-:1"0"1(/l~- ~ .... ~ ~ : ; ;:J l:l('() 0 0 -· ~.._.....o.
::r' ~ ('1)
"1
~
"'~"g
0
.....
(/) Illl:l "1 - ·0 (') l:l l:l < -· Ill ('j) 0.. o..o - · :::::::: "1 (/l (/) l:l (/lno ,_, (0 ::;.· rt ~
0
~(/l
~- ~
~§; -Ei~l:l" (/l
l:l"
-· 0
(t)
rt
~ 0
('1)
('
1
)
0
('
1
)
l:l<-<(D'IIll:lonoo..ClloCil>-oo.....
r t __ro
0:
~·
'-<
no -·
l:l Ill(/l~~>ool:lo..o ~ (/l
l:l·
l:l"
rt ~ -· 0 "1 l:l "1('1) o..(Jql:l"o..l:l" 0.. :;>:::(j)H->Cil(fl'-<:>-l:l(')
0 0..
~~ 0.. !::. (Jq .....
('1) "1('1) Ill ;::p
('j)
f"
('j)
('j)
:;.
~
"1
•
~
N
o
.
.
g
g
0
l:l
0'
0
(f)C::._....ro,_,~"':;>:::o..(f) 0 ' 0 Ill 0 s
0..
>-g. =1 Ul ro::-:::c;l:l .--.., l:l 0('1) "1 ('1)(')
s<-<.,:::St;ro l:l(/l('1) -· 0 (') "1
0 0..
"1 ('1) (/ll:l" 0
H->'OOi:l<CilO
0 Cl r t,_,ro?'os::<:&('l)nol:l">-o..g0l:l"Cll "1 rt('1) .... ;:::,.. 0 tl -·0 (')::;;:tsg-~s:E;s:tTj
l:l-· Ill ro0 0
no f"
C1l I
1'-tJ I ...1 ," 1 - '
,.
(/l
.....
I
cp _, I Q I (/l 0 0 Ill 9

c.

t: >-

0.::.

§

o' g

(') s u;·

s
s

s

[...,

~c.

b

g g

z w

:::!.

;:;: 82?8'~- 8'
zq g;g;.

5; :;; -·

c.

0.::.

..., .....
'

'

>
(')

~>;'

=

~
~

Q..

l)q

!3
~
.....
00

570.

Lower Triassic Ammonites

Glyptophiceras cf. gracile SPATH
Pl. 37, fig. 1
Compare:1930. Glyptophiceras gracile SPATH, p. 34, pl.
7, figs. 3-6; pl. 8, figs. 9a, b; lOa, b.
1935. Glyptophiceras gracile SPATH, p. 51, pl.
11, fig. 9; pl. 17, figs. 6a, b; pl. 18, figs.
6a, b; pl. 18, figs. Sa, b, 6.
1969. Glyptophiceras gracile TROMPY, p. 90.

Description: Shell evolute, serpenticones with laterally compressed whorls.
The ornamentation of shell surface ofthe outer whorl is characterized by acoarse, sigmoidal costation, which tending to degenerate into striation on theventral and umbilical margin.
Eachcostations are irregular in their prominence, but in general, they are mostprominent at about 1/3 height of theflank. The umbilicus is about 2/5 diameter of the shell, and the height of
the last whorl is about 1/3 diameter ofthe outer whorl. Suture ceratitic, which
consists of entirely rounded saddles and
2

I

1~

Q

12mm.

Fig. 5. Suture line (1) and cross sectionof the whorls (2) of Glyptophiceras cf. gracile
SPATH from the Hiraiso Formation at Monzen, Hiraiso, Motoyoshi-cho, Motoyoshi-gun,
Miyagi Prefecture, in the Kitakami Massif.

343

serrated lateral lobes. Of these, theexternal saddle is broad, the first laterallobe is deeply serrated, and the secondary lateral lobe is shallow and narrow.
The umbilical series of suture is simple
and short.
Remar!zs: The present material is
the first ammonite which occurred fromthe Hiraiso Formation at type locality.
Fortunately, the specimen is well preserved the shell sculpture and septa.
The first occurrence of the genus Glyptophiceras from japan was recorded by
NAKAZAWA and SHIMIZU (19S6) from theblack shale at Tomisu, Hyogo Prefecture,southwest japan, and this ammonite
was described by them as the name of
Glyptophiceras japo7Iicum. In the shellornamentation and the whorl characterthe present material is very similar
with those of G. gracile SPATH fromthe Otoceratan beds of Greenland. The
species of G. gracile has a variable
shell ornamentation as pointed out by
SPATH himself (1935, p. 52) and has arather weak sculpture in ornamentation
than those of G. aequicostatum (DIENER)(genotype) from the Himalayas (DIENER,
1913). The species of Glyptophiceras
were originally described by DIENER(1913) from the Ophiceras beds at Pastannah (Pastun) in Kashmir as Xenodiscus. Up to date, the most of species of
Glyptophiceras has been described from
East Greenland and Kashmir. Recently,
two species of Glyptophiceras were

Measurements of Glyptophiceras spp. (in mm):D']LKU-402
Glyptophiceras
cf. gracile
G. gracile(type specimen)
by SPATII (1930)

H

62.9(44.8)

19. 7

44.8

14.8

w

11.8

u

H/D

38.6(17.4)

0.31

20.9

0.32

W/H

U/D
0.45

0. 79

0.47

344

Yuji BANDO

Measurements of Flemingites sp. (in mm) :JM 11210

D

H

41

20.6

w

u

H/D

U/D

10.8

0.50

0.26

(every measurements were measured in the short axis of the whorl)

described from the Induan beds ofPrimorye in Russia, i.e. G. tobisiense
KIPARISOVA and G. (?) ignotum KIPAR.
(KIPARISOVA, 1961). And also, POPOV(1961) described G. pascoei SPATH fromthe Otoceras zone of Induan stage in
Eastern Verkhoyan, northeast Russia.
Occurrence and geological horizon :Calcareous sandy shale at Monzen,
Motoyoshi-cho, Motoyoshi-gun, Miyagi
Prefecture. Lower Part of the Hiraiso
Formation. Lowest Scythian, Otoceratan or Lowest Induan stage.
Reg. No. GLKU*-C402. Coll. S. ONODERA.
Family Flemingitidae HYATT, 1900
Genus Flemingites WAAGEN, 1892
Flemingites sp.

the Meekoceras bed of the Osawa Formation at the type locality in the Kitakami Massif. judging from the formof the whorls and the shell sculpture
the present material belongs to the genus
Flemingites, but specifically it is impossible to identify with any species of
Flemingites because the preservation of
the shell is poor. The present specimen
was yielded with Meelwceras, Euflemingites and Xenoceltites ? from the blackshale of the Osawa Formation.
Occurrence and geological horizon :Black shale of the Osawa Formation at
Osawa (type locality), Motoyoshi-cho,Motoyoshi-gun, Miyagi Prefecture, inthe southern part of the Kitakami
Massif. Upper Scythian, Owenitan.
Reg. No. JM*11210. Coll. K. NAKAZAWA.

Pl. 37, fig. 2

Genus Eujlemingites SPATH, 1934

Description: Shell rather evolute, laterally compressed, with shallow umbilicus. Whorl sides almost flat. Umbilicalshoulder of the whorl rounded. Sculpture preserved only on the outer whorl
and they consists of numerous, faintspiral strigations and weak sigmoidal
radial ribs. Suture unfortunately unknown. The height of the outer whorl
is about 1/2 of the diameter of the shelland the width of the umbilicus is about
1/4 of the diameter of the shell.
Remarks: The present material is a
fragmentary specimen (JM 11210) from

Euflemingites sp.

* Abbreviation for the Geological Laboratory, Kagawa University, Takamatsu, Japan.

Pl. 37, fig. 5

Description : Shell rather involute,
laterally compressed, with wide umbilicus. Shell surface ornamented with
distinct concentric strigations as inEujlemingites guyerdetiformis WELTER(genotype) from Timor (WELTER, 1922,
p. 117, pl. 109, figs. 10-12; SPATH, 1934,
p. 115, fig. 29). The strigations gradually become strong from the umbilicus
to the body whorl. The ventral part

* Abbreviation for Japanese Mollusca in
the Department of Geology and Mineralogy,
Kyoto University, Kyoto, Japan.

570.

Lower Triassic Ammonites

and septa are unfortunately missing.
Remarks: The shell ornamentation of
the present material closely resembles
those of Eufiemingites, but the specificidentification seems to be impossible
because the ventral part and sutures
are missing. The genus Eujlemingites
is distinguished from Flemingites by thestrong strigations (SPATH, 1934, p. 115),
but the sutures resemble each other.
The species of Eufiemingites have beenrecorded from Timor (WELTER, 1922;
SPATH, 1934), United States of America(SMITH, 1932), Spitsbergen (SPATH, 1951),
Arctic Canada (TOZER, 1961), South China(CHAO, 1959), and from the Himalayas(DIENER, 1897). The genus Eufiemingites
predominate in the Owenitan stage of
the Lower Triassic, especially in the
Meekoceras zone. In japan, the recordof the present material is the first andit was found in association with Meekoceras and Xenoceltites ? from the blackshale of the Osawa Formation. No otherspecies of Eufiemingites has been reported from the Lower Triassic beds ofJapan.
Occurrence and geological horizon :Black shale of the Osawa Formation at
Osawa (type locality), Motoyoshi-cho,Motoyoshi-gun, Miyagi Prefecture, inthe southern part of the Kitakami
Massif, northeast japan.
Owenitan,
Lower Triassic.
Reg. No. JM 11206. Coil. K. NAKAZAWA.
Family Meekoceratidae W AAGEN, 1895
Subfamily Meekoceratinae
W AAGEN, 1895

345

Genus JV[eekoceras HYATT in
C. A. WHITE, 1879

Meekoceras sp. A
Pl. 37, fig. 3

Description : Shell laterally compressed, rather evolute, discoidal whorls withflattened sides and shallow umbilicus.
The width of the umbilicus is about 1/5of the total diameter of the shell. Surface with fine radial folds and fine
growth strigation on the umbilical sidesof the whorl. Septa ceratitic, withentire saddles and serrated lobes, but
the ventral lobe is unknown. The firstlateral lobe is large and distinctly serrated, the second lateral lobe is smaller
than the first, and following this there
is a series of auxiliary lobes. The
height of the last whorl is about twice
the diameter of the umbilicus. The
width and exact diameter of the shell
are unfortunately unknown.

17.4 mm.
Fig. 6. Suture line of Meekoceras sp.
from the Osawa Formation at Osawa, Motoyoshi-cho, Motoyoshi-gun, Miyagi Prefecture.

Remarks: The present material isfrom the black shale of the Lower Triassic Osawa Formation at Osawa (typelocality). The preservation is very poor
and all of the materials from the locality mentioned above are laterally de-

Measurements of Meekoceras sp. A (in mm) :D

JM 11208

H

17.0

w

u
10.1

H/D

W;H

u;o

YnJi BANDO

346

diameter of the shell. The venter isnarrow and rather fiat, with subangularventral shoulders. The surface is ornamented with low radial folds and faintradial striae of growth. Septa faint,
but unknown precisely, consisting of
entire lateral saddles and indistinct lateral lobes, but the serration of the lobes
is unknown.
Remarks: The present specimen isprobably an immature form, and thepreservation of the shell is rather well
except for the septa. Considering fromthe shell characters the material at handbelongs to the genus lv!eekoceras, but
specific identification is impossible because the septa are not preserved. In
the whorl shape and ornamentation ofshell the present material resembles
Meekoceras gracilitatus WHITE from
North America.
Occurrence and geological horizon :Black shale of the Osawa Formation at
Osawa, Motoyoshi-cho, Motoyoshi-gun,
Miyagi Prefecture, in the Kitakami
Massif. Lower Triassic Owenitan stage.
Reg. No. JM 11207. Col!. K. NAKAZAWA.

formed and their whorl sections arealmost unknown.
The present material is closely related
to l'v!eekoceras gracilitatus WHITE from
North America \WHITE, 1879 ; SMITH,
1904; HYATT and SMITH, 1905; SMITH,
1934; SPATH, 1934; KUMMEL, 1954; KUMMEL in ARKELL et a!., 1957; KUMMELand STEELE, 1962; TOZER, 1961) in theshell ornamentation, umbilicus and thesepta, but the precise identification is
impossible because of the state of preservation of the present material. Judging from the septa, especially from theform of the lateral lobes and auxiliary
series, the present specimen is thought
to belong to the genus lv!eekoceras.
Occurrence and geological horizon :Black shale of the Osawa Formation at
Osawa, Motoyoshi-cho, Motoyoshi-gun,
Miyagi Prefecture, in the Kitakami
Massif. Lower Triassic Owenitan ammonite stage.
Reg. No. JM 11208. Col!. K. NAKAZAWA.
A1eekoceras sp. B
Pl. 37, fig. 7

Family Xenoceltitidae SPATH, 1930

Description : Shell involute, laterallycompressed, discoidal, with narrow umbilicus and venter. The whorl sides
are slightly convex and the width broad.
The umbilical shoulders are steep andtheir walls high angled. The living
chamber occupies about 2/3 volution of
the outer whorl and the height of whorls
is about 1/2 of the total diameter of theshell. The diameter of the umbilicus isvery narrow being_ about 1/10 of the

Subfamily Xenoceltitinae SPATH, 1930
Genus Xenoceltites SPATH, 1930
Xenoceltites? sp.
Pl. 37, fig. 4

Description : Shell small, evolute, laterally compressed, rather el!ipticonic
serpenticone with radial week ribs on

A1easurements of A1eekoceras sp. B (in mm) :D

JM 1120724.6(15.9)

H
13.8(~.0)

w

u

H/D

u;D

3. 2(2. 0)0.56(0.50)

0.13(0.12)

570.

Lower Triassic Ammonites

347

Measurements of Xenoceltites? sp. (in mm) :JM 11209DH

14.0(10.1)

5.0(3.5)

sides. The ribs are irregular and costated and a few weak constrictions areobserved on the shell. The depth of
the umbilicus is shallow and the width
is a little \vider than half of the diameter of the shell. The height of thesh•.)ll is about 1/3 of the total diameterof the conch. The septa are missing.
Remarhs: The material at hand is an
iPcomplete specimen, however the general shape of the conch may be identified with the genus Xenoceltites subevolutus SPATH (1934, p. 130, pl. 2, fig. 2;
pl. 8, fig. 2; pl. 9, fig. 4; pl. 11, fig. 2)
from the beds of his upper Eo-Trias ofSpitsbergen, but the present materialshows a more evolute style. From theshape of the conch the present specimen
also resembles X. evolutus (WAAGEN)(W AAGEN, 1895, p. 32, pl. 10, fig. 3, as
Dinarites; FREBOLD, 1930, p. 16-18, pl. 3,
fig. 6; SPATH, 1934, p. 127) from Chhidru
of the Salt Range of Pakistan, but it isunfortunate that precise identification
can not be done because of the poor
preservation. The last mentioned allied
species has been described from theTao Formation of Shikoku, japan, as
X. aff. evolutus (W AAGEN) and is associated with the fauna of Anasibirites
and J\1eehoceras, thus the present writerplaces its stratigraphical horizon in theOwenitan ammonite stage of the Lower
Triassic (BANDO, 1964, p. 86).
Occurrence and geological horizon :Black shale of the Osawa Formation at
Osawa, Motoyoshi-cho, Motoyoshi-gun,
Miyagi Prefecture, in the Kitakami
Massif. Lower Triassic Owenitan stage.
Reg. No. JM 11209. Coli. K. NAKAZAWA.

w

u

H;D

U/D

6.5(4.2)

0.35(0.35)

0.46(0.42)

Family Danubitidae SPATH, 1951
Genus Danubites MOJSISOVICS, 1893
Danubites aff. ambiha DIENER
Pl. 38, fig. 1
1895. Danubites ambi!w
29, fig. 2.

DIENER,

p. 104, pl.

Description: Evolute, laterally compressed, with wide umbilicus andbroadly rounded venter. Conch slowly
increasing in height and shallowly embracing the inner whorls. The umbilical shoulders with steep angle and 11arrow wall. The surface ornamented withmany distinct radial ribs which aremost prominent at 2/3 height of theflanks and diminishing at the ventral
margin. There are about 30 ribs on
the flanks of the outer whorl. The
septa ceratitic, consisting of broad lateral saddles and rather narrowly denticulated lateral lobes. The second lateralsaddle situated on the umbilical shoulders and rather low in height and broad.
The external saddle is very high, but
the ventral suture is unfortunately
missing. The first lateral lobe denticulated with about 3 or 4 points atbottom. The length of the body whorl
is equal to about half of the outer whorl.
Remarhs: The septal feature of thepresent material is characterized byhigher, elongated ventral saddle, andlower broad lateral saddles, and bothshow a remarkable contrast. Thesefeatures are clearly observed on the
septa of D. ambiha DIENER from theHimalayan M uschelkalk, and the shell

Yuji BANDO

348

lvfeasurements of Danubites aff. ambika DIENER (in mm):

IGPS coli. cat.l
no. 91406
Dm:--:E~'s typespeciesu

H;D30.5(15.1)

0. 30(0. 32)

18

0.30

w

D

H

57.1(30.0)

17.2(10.4)

43

15

14.5

ornamentations of both the present material and the Himalayan species resemble one another. Some differences areobserved in the shape of the whorl
section, especially the Himalayan species shows greater width of whorls
than the present material. Danubites
kansa DIENER from the Himalayan Muschelkalk also resembles the present specimen in the shell ornamentation, but
the suture line differs remarkably.
Danubites japonicus SHIMIZU (SHIMIZU,
1930, p. 69, pl. 24, fig. 5), from the Isatomae Formation at Inai, 0 jika-gun,
Miyagi Prefecture, has a wider umbilicus and more abundant radial ribs on
the surface of the whorls than thoseof the present material. From Japan
another species of Danubites was described by SHIMIZU (1930) as D. cf. kansa
DIENER from the Isatomae Formation at
Kudanohama, Utazu-cho, Motoyoshi-gun,
Miyagi Prefecture; he regarded the age
as Anisian.
Occurrence and geological horizon :Black shale in the alternation of sandstone and shale of the Osawa Formation
at Konori-hama, Onagawa-cho, Ojikagun, Miyagi Prefecture, in the southern
Kitakami Massif. Uppermost Scythian,
Prohungaritan ammonite stage or Leio-

w;r-r

U/D

0.53(0.50)
0.30

0.42

phyllites zone.
Reg. No. IGPS col!. cat. no. 91406. CoiLY. ONUKI and K. SASAKI.
Danubites sp.
Pl. 38, fig. 2

Description: Evolute, slightly embracing, slowly increasing in height ofwhorls; umbilicus very wide; surface
ornamented with dense, strong radialribs which extend straightly from theumbilical to the ventral margin. It is
unfortunate that the septa, ventral partand the body whorls are missing in thepresent material.
Remarks: The material at hand is an
incomplete single specimen. Consideringfrom the shell ornamentation the present material may belong to the genus
Danubites, but specific identification is
impossible. The species of Danubites
have been reported from the Lower
Triassic of India, Siberia, Idaho andCalifornia in North America, but inJapan, up to the present, Danubites has
been described from the lower part of
the Middle Triassic Inai Group in the
Kitakami Massif of Northeast Japan.
Occurrence and geological horizon :Black shale in the alternation of sand-Measurements of Danubites sp. (in mm) :IGPS coli. cat.
no. 91407

D

H

27.0

7.1

w

u

H;D

u;o

13.2

0.26

0.50

570.

Lower Triassic Ammonites

stone and shale of the Osawa Formation
at Konori-hama, Onagawa-cho, Ojikagun, Miyagi Prefecture, in the southernpart of the Kitakami Massif. Uppermost Scythian, Prohungaritan ammonite
stage or Leiophyllites zone.
Reg. No. IGPS col!. cat. no. 91407. Col!.
Y. ONUKI and K. SASAKI.
Family Ussuritidae HYATT, 1900
Genus Leiophyllites DIENER, 1915
Leiophyllites ct. pitamaha (DIENER)
Pl. 37, fig. 6
Compare:1895. Monophyllites pitamaha DIENER, p. 107,
pl. 31, figs. 7a-c, 5 ? and 8 ?
1915. Leiophyllites pitamaha DIENE-R, p. 205.
1934. Leiophyllites pitamaha SPATH, p. 297.
1968. Leiophyllites pitamaha SHEVYREV, p.
112, pl. 6, fig. 3.

Description: Shell evolute, laterallycompressed, slowly increasing in height,
with serpenticone coiling whorls. The
outer whorl slightly embracing the inner
whorls; the umbilicus width very broadand shallow. The surface is ornamented with faint radial fine striations ofgrowth and the sides are smooth androundly convex. The venter is narrowly
rounded and its shoulders indistinctly
rounded. The umbilical shoulders gently
rounded to the umbilicus. The maximum
width is at the middle height of theflanks. Septa unknown.
Remarks: Two specimens were stud-349

ied. The specimens described here werecollected from the lowermost part of the
Fukkoshi Formation at the quary of
Konori, about 300m west of Konori andat the boundary between the Lower
Triassic Osawa Formation and the Fukkoshi Formation (Uppermost Scythianto Lower Anisian). The genus Leiophyllites was first described from Japanby SHIMIZU (1930) from the Isatomae
Formation at Kudano-hama, Isatomae,
Utazu-cho, Motoyoshi-gun, Miyagi Prefecture, at about 30 km north of Konori.
No species of Leiophyllites have beenrecorded from any other localities of
the Lower and Middle Triassic formations of the Kitakami Massif. According to the field observations the horizon
that yielded the present ammonite may
belong to the Fukkoshi Formation (Lowermost Anisian-Uppermost Scythian).
The materials at hand are poorly pre. served, but the ornamentation of theshell, the umbilicus and the whorl
characters are well preserved. The
character of the whorl shape, ornamentation and the umbilicus resemble thegenus Leiophyllites. Specificially, thespecimens illustrated here show a close
resemblance with Leiophyllites pitamaha
DIENER (DIENER, 1895, p. 107-108, pl. 31,
figs. 5, 7, 8, as Monophyllites) in thewhorl section, the form of umbilicus
and the shell ornamentation. But thestriations on the shell of DIENER's Himalayan form are feebler than those on
our specimens.
Another Himalayan

Measurements of Leiophyllites cf. pitamaha (DIENER) (in mm):D
IGPS col!. cat.
no. 91403-1
IGPS col!. cat.
no. 91403-2

29.1(18.8)

H

w

u

9.0(5. 7)

11.95

7. 8(3. 8)

15.2(8.0)

H!D

u;o

0. 26(0. 20)

0.53(0.42)

YuJi BANDO

350

species, Leiophyllites pradyumna DIENER(DIENER, 1895, p. 106-107, pl. 31, figs. 3-4
as Monophyllites) has denser striationsof growth or more delicate striae ofgrowth near the umbilical margin compared with L. pitamaha.
Occurrence and geological horizon :Black shale in the alternation of sandstone and shale of the Osawa Formation
at Konori-hama, Onagawa-cho, Ojikagun, Miyagi Prefecture, in the southern
Kitakami Massif. Uppermost Scythian,
Prohungaritan ammonite stage or Leiophyllites zone.
Reg. No. IGPS coli. cat. no. 91403. Coil.
Y. ONUKI and K. SASAKI.
Leiophyllites aff. pradyumna (DIENER)?I. 38, fiz. 3
Compare:1895. Monophy!lites pradyumna DIENER, p.
106, pl. 31, figs. 3-4.
1915. Leiophyllites pradyumna DIENER, p. 205.
1934. Leiophyllites pradyumna SPATII, p. 306.
1968. Leiophy!lites pradyumna ZAKIIAROV, p.
124, pl. 23, figs. 2, 3.

Description: Evolute, laterally compressed, with wide umbilicus and distinct radial striations of growth. The
width of the umbilicus is about half ofthe total diameter of the shell and theheight of the shell is about 1/3 of thetotal diameter of the shell. The umbilical and ventral shoulders are unknown because of lateral deformation.

The septa are also unknown.
Remarks: judging from the shell ornamentation and umbilical features thepresent material resembles L. pradyumna(DIENER) from the Himalayan M uschelkalk, but comparison of their septa andwhorl section is difficult because of theincomplete preservation of our material.
As already mentioned by DIENER (1895)
and SPATH (1934) the shell surface ofL. pradyumna is characterized by striations more distinct than the otherspecies of Leiophyllites and by the periodical exterior fringed ribs which, however, do not reach the umbilicus. The
present material clearly exhibits thesefeatures on the surface of the shell.
Up to date, Leiophyllites pradyumna has
been described from the Himalayas andTimor. Most recently, ZAKHAROV (1968)
described L. pradyumna from the Lower
Triassic in the southern Primorye. In
japan, this is the first occurrence of
this species. L. cf. pseudopradyumna
WELTER related to the present species
has been already reported by SHIMIZU(1930) from the Isatomae Formation at
Kudano-hama, Utazu-cho, Motoyoshigun, Miyagi Prefecture, in the Kitakami Massif.
Occurrence and geological horizon:
Black shale in the altern,ation of sandstone and shale of the Osawa Formation
at Konori-hama, Onagawa-cho, Ojikagun, Miyagi Prefecture, in the southern
Kitakami Massif•. Uppermost Scythian,Measurements of Leiophyllites aff. pradyumna (DIENER) (in mm) :D

IGPS col!. cat.

no. 91404

H

w

u

H/D

W/H

0. 47(0. 52)

25. 7(12.9) 0.32(0.31)

54.3(25.0) 17.6(7.8)

u;D

L. pradyumna

42

12.5

10

21

0.29

0.8

0.5

by DIENER

26

9

9

12

0.34

1.0

0.47

(1895)

570.

Lower Triassic Ammonites

Prohungaritan ammonite stage or Leiophyllites zone.
Reg. No. IGPS coiL cat. no. 91404. Coli.
Y. ONUKI and K. SASAKI.
References
BANDo, Y. (1964): The Triassic stratigraphy
and ammonite fauna of Japan. Sci. Rep.
Tohoku Univ., 2nd Ser. (Geol.), _vol. 36,
p. 1-137, pis. 1-15.
- - (1968) : Stratigraphic problems concerning the newly occurred Lower Triassic
ammonites from the Kitakami Massif
and Maizuru Zone. Mem. Fac. Educ.,
Kagawa Univ., pt. 2, no. 174, p. 1-7,
pis. 1-3.
CHAo, K.C. (1959) : Lower Triassic ammonoids from Western Kwangsi, China.
Palaeont. Sinica, N.S. B, no. 9, p. 1-355,
pis. 1-45.
DIENER, C. (1895) : Himalayan Fossils. The
Cephalopoda of the Muschelkalk. Pal.
Indica, 15th Ser., 2, pt. 2, p. 1-118, pis.
1-31.
- - (1913) : Himalayan Fossils. Triassic
faunae of Kashimir. Ibid., N.S., 5, p.
1-133, pis. 1-13.
- - (1915) : Fossilium Catalogue. 1, pt. 8.
Cephalopoda Triadica, p. 1-369, Berlin.
- - (1916) : Japanische Triasfaunen. Akad.
Wiss. Wien, Denkschr., vol. 92, p. 405-549,
pl. 1.
FREBoLD, H. (1930) : Die Altersstellung desFischhorizontes, des Grippianiveaus unddes unteren Saurierhorizontes in Spitsbergen. Skr. Svalb. og. Ishavet, vol. 28,
p. 1-36, pis. 1-6.
HYATT, A. and SMITH, J.P. (1905): The
Triassic cephalopod genera of North
America. U.S.G.S. Prof. Paper 40, p.
1-394, pis. 1-85.
IcHIKAWA, K. (1948) : Stratigraphy of theLower and Middle Triassic in the TsuyaIsatomae districts in the southern Kitakami Massif.. j. Geol. Soc. japan, vol.
.
53, p. 79 (in Japanese).
- - (1951) : Tria$sic system in the southernpart of the Kitakami Massif, in .the Tri-351

assic stratigraphy of Japan. Geol. Surv.
japan, Rep. Spec. No., p. 7-26 (in Japanese).
INA!, Y. (1939) : Geology of Shizukawa andits environs in Miyagi Prefecture. j.
Geol. Soc. japan., vol. 46, p. 231-242 (inJapanese).
KIPARISoVA, L.D. (1961): Paleontologicalfoundation for the stratigraphy of theTriassic deposits of the Primorye region. Part 1, Cephalopoda. Vsesoiuzuyi
Nautsuno-Issledovatelskii Geol. Inst.
(VSEGEI), n. ser. 48, p. 1-278, pis. 1-38(in Russian).
KIPARisovA, L.D. and PoPov, Yu. N. (1956):
Subdivision for the Lower Triassic system into stages. Dokl. Akad. Nauk.
S.S.S.R., vol. 109, no. 4, p. 842-845 (inRussian).
- - and - - (1961) : On the subdivisionof the Lower Triassic into two stages.
Bull. Interdept. Stratigr. Comm., vol. 3,
p. 24-37 (in Russian).
- - and - - (1964) : The project of subdivision of the Lower Triassic into stages.
Internat. Geol. Congr., 22nd Session. Dokl.
Soviet Geol., Problema 16a, Acad. Nauk.
S.S.S.R., p. 91-99 (in Russian with English summary).
KuMMEL, B. (1954) : Triassic stratigraphyof southeastern Idaho and adjacent areas.
U.S.G.S. Prof. Paper 254, p. 165-194.
- - (1957) : In "Treatise on Invertebrate
Palaeontology", Part L. Mollusca 4,
Cephalopoda, Ammonoidea. Geol. Soc.
Amer. and Univ. Kansas Press, p. 1-490.
- - (1969) : Ammonoids of the Late Scythian (Lower Triassic). Bull. Museumof Camp. Zool., Harvard Univ., vol. 137,
no. 3, p. 311-559, pls. 1-71.
KuMMEL, B. and STEELE, C. (1962) : Ammonites from the Meekoceras gracilitatis
Zone at Crittenden Spring, Elko County,
Nevada. j. Paleont .• vol. 36, no. 4, p.
638-703, pis. 99-104.
KuRoSAWA, M. (1929): Geology of MaiyaShizugawa area in the Kitakami Massif(Graduation Thesis, MS, in Japanese).
MABUTI, S. (1932) : Stratigraphy of the
Tatsukane ·Mass in southern iGtakami

352

Yuji BANDO

Massif (Graduation Thesis, MS, in Japanese).
N AKAZAW A, K. (1958) : The Triassic systemin the Maizuru Zone, southwest Japan.
Mem. Coil. Sci., Univ. Kyoto, Ser. B,
vol. 24, p. 265-313.
NAKAZAWA, K. and BANDO, Y. (1968): Lower and Middle Triassic ammonites from
Portuguese Timor (Palaeontological studyof Portuguese Timor, 4). Mem. Fac.
Sci., Kyoto Univ., Ser. Geol. & Min.,
vol. 34, p. 83-114, pls. 4-7.
ONUKI, Y. (1959) : Geology of the Kitakami
Massif. Geological explanation of lwate
Prefecture II, p. 1-189 (in Japanese).

- - (1969) : Geology of the Kitakami Massif, Northeast Japan. Contr. Inst. Geol.
Pal., Tohoku U hiv., no. 69, p. 1-239, pls.
1-4.
PoPov, Yu. N. (1961): Triassic ammonoids
of northwestern U.S.S.R.
NautsunoIssledovatelskii Inst. Geol. Arckt., Trudy,
vol. 79, p. 1-124, pis. 1-25 (in Russian).
SHEVYREV, A.A. (1968) : Triassic ammonoidsof southern U.S.S.R. Akad. Nauk SSSR,
Pal. Inst., Trudy, vol. 119, p. 1-252, p!s.
1-21 (in Russian). ·SILBERLI:'<G, N.J. and TozER, E.T. (1968):
Biostratigraphic classification of the Marine Triassic in North America. Geol.

Explanation of Plate 37
Glyptophiceras cf. gracile SPATH
GLKU-C402 x 1, from the calcareous sandy shale at Monzen, Motoyoshi-cho, Motoyoshigun, Miyagi Prefecture. Lower part of the Hiraiso Formation. Lowest Scythian,
Otoceratan or Lowest Induan stage.
Fig. 2. Flemingites sp.
JM 11210 x 1.2, from the black shale of the Osawa Forma~ion at Osawa, Motoyoshicho, Motoyoshi-gun, Miyagi Prefecture. Upper Scythian, Owenitan stage.
Fig. 3. Meekoceras sp. A
JM 11208 x 1.5, Loc. ibid. Upper Scythian, Owenitan stage.
Fig. 4. X enoceltites ? sp.
JM 11209 X 1.3, Loc. ibid. Upper Scythian, Owenitan stage.
Fig. 5. Eujlemingites sp.
JM 11206 x 1.4, Loc. ibid. Upper Scythian, Owenitan stage.
Fig. 6. Leiophyllites cf. pitamaha (DIENER)
IGPS, coil. cat. no. 91403 x 2, from the Osawa Formation at Konori, Onagawa-cho,Ojika-gun, Miyagi Prefecture. Uppermost Scythian, Prohungaritan or Leiophyllites
zone.
Fig. 7. Meekoceras sp. B
JM 11207 x 1.4, from the calcareous sandy shale of the Osawa Formation at Osawa,
Motoyoshi-cho, Motoyoshi-gun, Miyagi Prefecture. Uppe1· Scythian, Owenitan stage.
Fig. 8. Leiophyllites sp.
IGPS, col!. cat. no. 91405 x 1.3, from the Osawa Formation at Konori, Onagawa-cho,Ojika-gun, Miyagi Prefecture. Uppermost Scythian, Prohungaritan or Leiophyllites
zone.
Fig. 1.

The specimens of Figs. 2, 3, 4, 5 and 7 a're preserved in the Department of Geology andMineralogy, Kyoto University, Kyoto; and the specimens of Figs. 6 and 8 are preserved in
the Institute of Geology and Paleontology, Tohoku University, Sendai. The first specimen,
Fig. 1, being preserved in the Department of Geology, University of Kagawa, Takamatsu.

BANDO:

Lower Triassic Ammonites

Plate 37

4

3

7

570.

Lower Triassic Ammonites

Soc. Amer., Spec. Paper 110, p. 1-63.
SHIMIZU, S. (1930) : On some Anisic ammonites from the Hollandites Beds of theKitakami Mountainland. Sci. Rep. Tohoku Imp. Univ., 2nd Ser. (Geol.), vol.
14, p. 63-74, pl. 24.
SHIIDA, I. (1939) : On the Geology of Kesennuma-cho and its environs in Miyagi Prefecture. Contr. Inst. Geol. Pal., Tohoku
Univ., no. 33, p. 1-72.
SMITH, J.P. (1914) : The Middle Triassic
invertebrate fauna of North America.
U.S.G.S. Prof. Paper 83, p. 1-254, pis.
1-99,
- - (1.932) : Lower Triassic ammonoids ofNorth America. Ibid., 167, p. 1-199, pis.
1-81.
SPATH, L.F. (1930): The Eotriassic invertebrate fauna of East Greenland. Med.
om Gr¢nland, vol. 83, p. 1-90, pis. 1-12.
- - (1934) : The Ammonoidea of the Trias(1) ; Catalogue of the Fossil Cephalopoda
in the British Museum (Nat. Hist.), pt.
4, p. 1-521, pis. 1-18.
- - (1951) : The Ammonoidea of the Trias(II) ; Ibid., pt. 5, p. 1-228.
TozER, E.T. (1961): Triassic stratigraphy
and faunas, Queen Elizabeth Island,
Arctic Archipellago. Geol. Surv. Canada,Mem. 316, p. 1-116, pis. 2-30.
- - (1965) : Lower Triassic stages and am-

Fukkoshi
Hirai so
Inai
Isatomae
Ishinomaki
Konori
Kudano-hamaMonzenMotoyoshi}!l~-'¥ TOll::J:j: 1*1
ffll[l]tj::p 5ftf
!]'

*
iJlT

1:\'1~
r~

±

"* "'

353

monoid zones of Arctic Canada. Geol.
Surv. Canada, Paper 65-12, p. 1-14.
- - (1967) : A standard for Triassic time.
Gelol. Surv. Canada, Bull. 156, p. 1.03,
pis. 1-10.
TOZER, E.T. and PARKER, J.R. (1968): Notes
on the Triassic biostratigraphy of Svalbard. Geol. Mag., vol. 105, no. 6, p.
526-542, pis. 25-27.
TRDMPY, R. (1969) : Lower Triassic ammonites from Jameson Land (East Greenland), in Notes on Triassic Stratigraphy
and Paleontology of North-Eastern Jameson Land (East Greenland). Med. om
Gr¢mland, Bd. 168, no. 2, p. 81.-116, pis.
1-2.
WAAGEN, W. (1895): Fossils from the Ceratite Formation. Pal. Indica, 13th Ser.
Salt Range Fossils, 2, p. 1-323, pis. i-40.
WELTER, O.A. (1922): Die Ammoniten derunteren Trias von Timor.
Pal. vonTimor, vol. 11, p. 83-154, pis. 1.55-171.
YEHARA, S. (1927) : The Lower Triassic
cephalopod and bivalve fauna of Shikoku.
japan. ]. Geol. Geogr., vol. 5, p. 135-172,
pis. 13-17.
ZAKI-IAROV, Yu. D. (1968): Lower Triassic
biostratigraphy and ammonoids in southern Primorye Region. Akad. Nauk SSSR,
Siberian Branch, Far East Geol. /nsf.,
p. 1-172, pis. 1-31 (in Russian).

Ojika
Onagawa
Osawa
Tao (Taho)
Tate
TomisuToyamaUtazu

4± ffi!:-9:. JlliR
133 :fili•(.;.•
lifJ

*
'6'

ffJ!j

~

~'=

~

i.$:

'"'

354

Yuji BANDO

Explanation of Plate 38
Fig. 1. Danubites aff. ambika DIENER
IGPS, col!. cat. no. 91406. x 2.
Fig. 2. Danubites sp.
IGPS, col!. cat. no. 91407. x 2.
Fig. 3. Leiophyllites aff. pradyumna (DIENER)
IGPS, col!. cat. no. 91404. x 2.

All illustrated specimens here are from the Osawa Formation at Konori, Onagawa-cho,Oshika-gun, Miyagi Prefecture, southern Kitakami Massif. Uppermost Scythian, Prohungaritan
stage of Leiophyllites zone. All specimens are preserved in the Institute of Geology and Paleontology, Tohoku University, Sendai. Coli. Prof. Y. 0NUKI and Mr. K. SASAKI.

BANDO:

Lower T1·iassic A??t??wnites

2

3

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Transactions and Proceedings of the PalaeontologicalSociety of Japan

September 30, 1970

New Series No. 79

CONTENTS
TRANSACTIONS
568. OHTA, Yoshihisa: A review of some Cretaceous corbiculids in North
America . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
569. HA YAMI, Tomoko : Miocene Bryozoa from Southwest Hokkaido, japan ... . 316
570.

BANDO, Yuji:

Lower Triassic ammonoids from the Kitakami massif . ... 337

PROCEEDINGS . . . . ... . .... . ..... ...... . ....... . ... ....... . . .... ............... 355