ISSN 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 135

Palaeontologi ca l Soc iety of Japa n
October 15, 1984

Itarn HAYAMI and Ikuwo OBATA

Co-Editors

Officers for 1983-1984
President: Yokichi TAKAYANAGI
Councillors:

Kiyotaka CHINZEI, Takashi HAMADA, Tetsuro HANAI, Yoshikazu HASEGAWA,

Itaru HAYAMI, Hisayoshi IGo, Junji ITOIGAWA, Tadao KAMEl, Tatsuaki KIMURA,
Tamio KOTAKA, Ikuwo OBATA, Tsunemasa SAITO, Tsugio SHUTO, Yokichi TAKAYANAGI, Toshimasa TANAIMembers of Standing Committee: Kiyotaka CHINZEI (General Affairs, Co-Editor of "Fossils"),
Takashi HAMADA (Foreign Affairs), Tetsuro HANAI (Member-at-large), Yoshikazu
HASEGAWA (Membership), Itaru HAY AMI (Co-Editor of Transactions), Hisayoshi IGO(Planning), Tatsuaki KIMURA (Finance), Ikuwo OBATA (Co-Editor of Transactions),
Tsugio SHUTO (Editor of Special Papers), Yokichi TAKAYANAGI (Co-Editor of"Fossils")
Secretaries: Katsumi ABE (General Affairs), Ienori FUJIYAMA and Juichi YANAGIDA (Special
Papers), Kunihiro ISHIZAKI ("Fossils"), Hiroshi NODA (Planning), Tatsuo OJI
actions)
Auditor: Toshio KOIKE

The ostracod carapace on the cover is an adult specimen of Manawa konishii
NOHARA (Suborder Palaeocopina, Family Punciidae) from the East China
Sea. (photo by K. ABE, x190)

All communication relating to this journal should be addressed to the

PALAEONTOLOGICAL SOCIETY OF JAPAN
c/o Business Center for Academic Societies,
Yayoi 2-4-16, Bunkyo-ku, Tokyo 113, Japan(Trans-Trans. Proc. Palaeont. Soc. Japan, N.S., No. 135, pp. 395-400, pI. 76, October 15,1984

782. ONTOGENESIS OF EHMANIELLA BlJRGESSENSIS RASETTI(TRILOBITA) FROM BURGESS SHALE, MIDDLE CAMBRIAN,YOHO PARK, BRITISH COLUMBIA*CHUNG-HUNG HU
Department of Earth Science, Taiwan Normal University, Taipei

Abstract. The present report describes the ontogenic development of a Middle
Cambrian trilobite: Ehmaniella burgessensis Rasetti from the Burgess Shale, Yoho
Park, British Columbia. The morphogenesis of this trilobite during its early growthstages are similar to those of Sao hirsuta Barrande, Crassifimbra walcotti (Resser),Glyphaspis cf. parkensis Rasetti, Yuknessaspis santaquinensis Hu, Trymataspis
convexus Hu, and Ehmaniella sp. etc. whereas in the late ontogenic stage the instars
are similar to most of its fellow member except for those of Crassifimbra walcotti
and Trymataspis convex us. These phenomena possibly indicate that these trilobites
are derived from the same common ancestor but differentiated into different
groups in later descendants.

Introduction

Hu, Yuknessaspis santaquinensis Hu (1972).
Glyphaspis parkensis Rasetti (Hu, 1971), andEhmaniella sp. (Kopasks-Merkel, 1981), etc. andevaluate their phylogenetic relationships.
The result of this study shows that the morphology of these trilobites during their earlier
ontogenic stages are very similar, but are differentiated into two different morphologic groups
during their later stages; i.e., Ehmaniella burgessensis, Yuknessaspis santaquinensis, Glyphaspis
cf. parkensis, Sao hirsuta, Ehmaniella sp. as one,and Trymataspis convex us, Crassifimbra walcotti
as another. This phenomenon suggests that they
are all derived from a common ancestor and had
a very close phylogenetic relationship but differentiated into separate phylogenic groups in later
descendants.
The author wishes to. express his thanks to
Dr. J. D. Aitken, Geological Survey of Canada,Calgary, Alberta, for his guidance during the field
trip to the Burgess Shale quarry, Yoho Park,

In the late summer of 1981, the author has anopportunity to participate in a field trip to thesouthern Canadian Rocky Mountains, Alberta
and British Columbia area. During this field trip a
few small pieces of black shale - the Burgess
Shale - were collected from the Walcott Quarry,
Mount field, Yoho Park, British Columbia. These
small piece of black shale yield very abundantlarval instars of Ehmaniella burgessensis Rasetti.
These show very well preserved ontogenetic
sequences of this trilobite.
The purpose of this report is to describe theontogenetic developmental stages of Ehmaniellaburgessensis imd to compare these stages withthose of the only known ptychoparioid trilobitesfrom the Middle Cambrian: Sao hirsuta Barrande(Whittington, 1959), Crassifimbra walcotti (Resser) (Palmer, 1958), Try matasp is convex us*Received June 6,1983.
395

396

Chun-Hung HU

British Columbia, 1981. Thanks are also go to
Dr. K. E. Caster, the University of Cincinnati,
for reading over the present manuscript andcorrecting the English text. The figured specimens are stored in the Geology Museum, University of Cincinnati, Ohio.
Systematic Paleontology
Genus Ehmaniella Resser, 1937
Type species: Crepicephalus
quadrans Hall and Whitfield, 1877

(Loganellus)

Ehmaniella burgessensis Rasetti
Pi. 76, Figs. 1-29; Text-fig. 1
Ptychoparia permulta Walcott, 1918, p. 145, pI.
21, fig. 1 (only).
Elrathia permulta (Walcott), Resser, 1937, p. 10.
Ehmaniella burgessensis Rasetti, 1951, p. 217, pI.
30, figs. 1-16.
Locality and horizon. The Walcott quarry,
Mount Field, Yoho Park, British Columbia,
Canada; Stephen Formation (Burgess Shale),
Bathyuriscus-Elrathina Zone, Middle Cambrian(Aitken, 1981).
Ehmaniella burgessensis Rasetti, ontogeny

The present studied materials are all slightly
deformed, and, therefore, the early larval instars
assigned to a certain growth stage are somewhat
arbitrary. Five ontogenic stages are recognizedand described as follows:
Anaprotaspid stage (PI. 76, Fig. 1 and Textfig. lA). The shield is round to oval in dorsal
view, gently convex, and is about 0.25 to
0.35mm in sagittal length; it is distinctly divided
into pleural lobes and axis by dorsal furrows; theforwardly expanded axis is composed of a large
frontal lobe, two pai~ of incompletely separated
knobs, and small terminal portion; a pair ofdistinct pits is marked at the sides of the frontal
lobe tetween the short eyebrow-shaped ridges
and the palpebral crests; the pleuraflobe is twice
as wide as the axis, gently convex, and protruding
into a pair of blunt saw-teeth at the posterolate-

ral margin of the shield. The surface of the shieldis possibly covered by faint granules; and one or
two pairs of very faint cephalic furrows may bepresent on the pleural lobes.
At this stage some specimens show the axis
with a median furrow and two pair knobs, butothers are cylindrical without distinct axial
segments. These phenomena may indicate different degrees of maturation within the same
growth stage, i.e., within the same larval stage,some of individuals may have grown faster thanothers. The figured specimen is the smallest
instar known from the studied material, and it
seems reasonable to assign it to the earliest
anaprotaspid stage.
This ontogenic stage is correlatable with thoseof Yuknessaspis santaquinensis Hu (1972),
Glyphaspis cf. parkensis Resetti (Hu, 1971), andCrassifimbra walcotti (Resser) (Palmer, 1958) for
all are of similar morphologic organization.
Metaprotaspid stage (PI. 76, Figs. 2-4 and Textfig. lB). The shield is round to roundly quadrate
in outline, moderately convex and measures from
0.35 to 0.50mm in length (sag.); the axis is madeof five axial segments, of which the frontal
segment is the largest and expanded forwardly,
the following three segments are about equal insize, and the last one is a small terminal portion;a pair of short eyebrow-shaped ridges protrude
laterally for a short distance from the anterolateral margin of the frontal lobe; the palpebral crest
arches anterolaterally from the frontal pits andends before it reaches the transverse mid-line of
the shield; the pleural lobe is more or less twice
the width of the axis. The surface of the shield isapparently granulate; there are faintly impressed
cephalic grooves on the pleural lobe, and anarrow distinct marginal border present along theposterior half of the shield.
The morphogenesis of the present stage ismarked by the absence of the median furrow,
five faintly defined axial segments, and theshield has changed from oval to roundly quadrate
in outline.
The morphologic features of this stage arecomparable to those of Crassifimbra walcotti(Palmer, 1958), Trymataspis cpnvexus (Hu,782.

Ontogenesis of Ehmaniella burgessensis1972), Yuknessaspis santaquinensis Hu, 1972,
Glyphaspis cf. parkensis (Hu, 1971), early andlate protaspis of Ehmaniella sp. (K. -Merkel,1981). All of their instars possess a cylindrical
axial lobe and a somewhat forwardly expanded
frontal lobe; the protopygidium is not yet
present, but there is a broad posterior shield
margin.
Paraprotaspid stage (PI. 76, Figs. 5-8 andText-fig. Ie, D). The shield is made up either ofa cephalic region and a transverse protopygidium
or of the cranidiurn without a pygidium; it issubround to trapezoidal in outline, gently convex; the shield is 0.50 to 0.75mm in length (sag.);
the axial lobe is strongly expanded from the firstglabellar furrow and gently broadens posteriorly
to the occipital ring; the paired eyebrow-shaped
ridges and the palpebral crests are well demarked
at the sides of the frontal lobe; the convex
pleural lobe of the fixigenal area is less than
twice as wide as the axis; the small protopygidium is lenticular and composed of one totwo segments. The surface of the skeleton iscovered by faint granules with coarse ones
scattered among them.
In the morphogenesis of the present stage theprotopygidium appears, the frontal pits havebecome shallower, the posterior fixigenal borderincreases in width, and the facial suture appears
in the frontal half of the shield; the facial sutureis short and convergently convex. The morphological characteristics of the present stage arecomparable to those of Yuknessaspis santaquinensis Hu, 1972, Glyphaspis cf. parkensis (Hu,1971), early meraspid stage of Crassifimbra
walcotti (Palmer, 1958), and protaspides of Sao
hirsuta Barrande (Whittington, 1959, fig. 88, AD), and possibly early and late metaprotaspidesof Ehmaniella sp. (K. -Merkel, 1981).
Early meraspid stage (PI. 76, Fig. 9-11, 15,
19-22 and Text-fig. IE). The cranidium is trapezoidal in outline with the anterior border slightly
arched forwardly; about 0.75mm to 1.00mm inlength (sag.); the glabella is oblong and expands
both forwardly and posteriorly from the second
segment; the glabellar furrows are incomplete
and deepen laterally the while being shallow
across the central line; the occipital ring is397

lenticular, convex, and bears a small mediantubercle; the forwardly arched anterior borderappears; it is narrow and makes contact at theanterior glabellar margin with a faint frontal
furrow; the palpebral ridges are distinctly elevated and terminate with small palpebral lobes;
the anterior facial suture line is convergently
convex and the posterior suture line is divergently convex; the fixigenal area is the same
width as the glabella and the posterior fixigenal
border is less than twice as wide as that of theoccipital ring; the skeletal surface is covered by
faint granules and a few coarse ones are scatteredamong them.
The assigned pygidium is round to semicircular in outline, gently convex, and is made offive or six segments which are not ankylosed as aplate-like structure but freely articulated; theslenderly conical axial lobe tapers posteriorly
and ends before reaching the posterior margin;
the pleural lobe is approximately twice the widthof the axis, and the pleural bands are arched
uniformly and each ends into a blunt terminal
spine; the intrapleural grooves are distinctly
marked.
The special characteristics of this stage arethat the anterior border first appears; the glabella
becomes short and broader than in the previous
stage; the facial suture-line cuts the cranidium
into a trapezoidal shape, and the palpebral lobe
moves short distance posteriorly from theanterior border.
This stage is equivalent to instars of equivalent
age in Yuknessaspis santaquinensis Hu, 1972,
Trymataspis convexus (Hu, 1972), Glyphaspis
cf. walcotti (Hu, 1971), the middle meraspis of
Crassifimbra walcot~i (Palmer, 1958), and thestage E-G of Sao hirsuta (Whittington, 1959),
and early meraspis of Ehmaniella sp. (K. -Merkel,1981). They all have similar morphologic characteristics at this ins tar.
Late meraspid stage (PI. 76, Figs. 12-14, 23,
26 and Text-fig. IF ,J). The cranidium is trapezoidal in outline, moderately convex; about 1.00
to 1.80mm in sagittal length; the glai?ella isoblong to truncato-conical, tapering slightly
anteriorly with a gently expanded frontal margin;
the glabellar furrows are complete; a narrow

Chun-Hung HU

398

B

A

D

c

G
E

F

J
H

K
L
Text-fig. 1. Ehmaniella burgessensis Rasetti.
A, an anaprotaspid shield, showing the broad axis and a median logitudinal furrow. x60; B, ametaprotaspid shield, showing the narrow axis and the development of the axial segments. x62;
C, D, two paraprotaspid shields, showing the presence of the protopygidium and the trapezoidal
cranidium. x 40; E, an early meraspid cranidium, showing the presence of the anterior border. x 25;
F, a late meraspid cranidium, showing the narrow preglabellar field. x 13; G,J, a meraspid and alibrigena, showing the freely articulated pygidial segments and the narrow librigenal platform. x 18,
x 10; R.I, two "female" cranidia, showing the narrow glabella. x4.5, x3.5; K, an holaspid pygidium.
x 5.5; L, a "male" cranidium, showing the broad glabella. x 3. 5.

782. Ontogenesis of Ehmaniella burgessensis
preglabellar field appears between the archedanterior border and the anterior glabellar margin;
it is slightly depressed medially and gently
convex laterally; the anterior suture lines areparenthetic and convex laterally; the posterior
suture lines are divergent posterolaterally fromthe medium-sized sickle-shaped palpebral lobe.
The surface of the skeleton is covered by bothfaint and coarse granules, and faint irregular or
subparallel ridges are present on the preglabellar
field and the fixigenae.
The assigned pygidium is made up of 3-5 segments, of which at least two or three are notankylosed with the terminal plate but in freely
articulated position; it is semicircular to round inoutline, and about 0.5 to 1.0mm in length (sag.);
the axial lobe is conical, tapering posteriorly andends before reaching the posterior margin; thepleural lobe is about the same width as that of
the axis, convex, and without a pygidial spines
or saw-teeth, except that the anterior freely
articulated thoracic segments are terminated by apair of projections; deep intrapleural grooves andsurface granules are distinctly marked along thepleural bands.
The assigned librigena of this stage is narrowcrescentic and has the lateral border well definedby a lateral furrow; the anterolateral border is
projected into a long sharply pointed spine andat the posterior end is a short genal spine; theocular platform possesses a large palpebral ringand the surface is covered by both different size
granules and faint radial ridges.
The morphogenesis of these late meraspid
skeletons are: the narrow preglabellar fieldappears; the glabella becomes truncato-conical;
the anterior facial suture increases in length andchanges from convergently convex to parenthetic
appearance; and the posterior fixigenal borderdecreases in width and becomes about the same
width as that of the occipital ring.
The ontogenic development of the present
stage is equivalent to that of the same aged instarsof Crassifimbra walcotti (Palmer, 1958), Trymatasp is convexus (Hu, 1972), Yuknessaspis
santaquinensis Hu, 1972, "degree" 6-12 of Sao
hirsuta (Whittington, 1959, fig. 88H, I), and late399

meraspis of Ehmaniella sp. (K. -Merkel, 1981, fig.
IF), but differs in some detailed morphologic
structures. It appears that the late meraspid of
Trymataspis convexus is morphologically very
similar to that of Crassifimbra walcotti; bothpossess a conical, rather convex glabella and thesame shaped cranidium. They show independentfeatures from their fellow members and form a
distinct group: that of Yuknessaspis santaquinensis, Ehmaniella burgessensis, Ehmaniella sp. (K.
-Merkel), Glyp hasp is cf. parkensis, and Sao
hirsuta, all with a low convex cylindrical glabella
and trapezoidal cranidium, forms another naturalgroup.
Summary
The ontogenic development of Ehmaniellaburgessensis Rasetti is described. The result of
this study indicates that the morphogenesis
during its early larval stages are very similar tothat of Trymataspis convexus Hu, Crassifimbra
walcotti (Resser), Yuknessaspis santaquinensis
Hu, Glyphaspis cf. parkensis Rasetti, Sao hirsuta
Barrande, and Ehmaniella sp. (K.-Merkel, 1981)
but differentiated into two different groups
during their late ontogenic period, i.e., Ehmaniella burgessensis, Glyphaspis cf. parkensis, Saohirsuta, and Ehmaniella sp. as a natural group,
Trymataspis convexus and Crassifimbra walcotti
is another. These phenomena are possibly theindication that these trilobites were derived fromthe same common ancestor but differentiatedinto separate groups with the passage of time andevolution.
References
Aitken, J. D. 1981. The Cambrian system inthe southern Canadian Rocky Mountains,
Alberta and British Columbia (Second
International Symposium on the Cambrian
System): Guide book for field trip 2. 61pp.
(USGS. Published, Colorado)
Hu, C. H. 1971. Ontogeny and sexual dimorphism of Lower Paleozoic Trilobita: Palaeo
ontographica Americana, vol. VII, no. 44,
p.31-155.
--1972. Ontogenies of two Middle Cambrian400

Chun-Hung HU

trilobites from Wasatch Mountains, Utah:
Acta Geol. Taiwanica, no. 15, p. 41-50.
(Taiwan)Kopask-Merkel, D. C. 1981. Ontogeny of Ehmaniella (Implications for trilobite ecology):
Short papers for the Second International
Symposium on the Cambrian System, p.
111-114. (USGS. Published, Colorado)
Palmer, A. R. 1958. Morphology and ontogenyof a Lower Cambrian ptychoparioid trilobite
from Nevada: Jour. Paleont., vol. 32, no. 1,
p.154-170.

Rasetti, F. 1951. Middle CilIIlbrian Stratigraphy
and faunas of the Canadian Rocky Mountains: Smith. Misc. Coli., vol. 116, no. 5,277p. (Washington)
Resser, C. E. 1937. Third contribution to nomenclature of Cambrian trilobites: Smith. Misc.
Coli., vol. 95, no. 22, 29p.
Whittington, H. B. 1959. Treatise on Invertebrate
Paleontology (Part 0), Arthropoda 1: Geol.
Soc. America and Univ. Kansas Press.
p.127-144.

7- ~ T { .y y .... ::I P ;.; t: 7 ·Hi :I -;J-. -i~lll!Ic7) rl'jm 7J ;.; -:f V 7*,c Burgess 1'(:fi~:::::~£tt
Ehlllaniella burgessellsis Rasetti c7)fllilf;H\~A:.: '7 ,j"/t.-::I oy H*E:I"~J: IJf*:mLt-:9='JtIl:h :/7V 7ij:~c7):::::~~1t Ehlllaniella burgessensis c7)fl/;jf1>:Jfi1=.~~Ci~J( Lt-:. E. burgessensis c7)Jll'!#I!
lUll;!:. Sao hirsuta, Crassijimbra walcotti, Glyphaspis d. parkensis, Yuknessaspis santaquinensis. Trymataspis convexus &0: Eh11laniella sp. c7)Jll'!tmJtJU: l~ fl17.:>. L7'J'L.:to)9='1f.JtlH;!:.:-~kUO)jf;~.r,fl::."Nt t..dl7.:>. J!1lt, E. burgessensis, Sao hirsuta, Glyphaspis cf.
parkensis, Yuknessaspis salltaquillensis, Ehmaniella sp. 7'J:-m. Crassifimbra walcolti&0: Trymataspis convexus 7'J:t oj -kil"C"Ji>7.:> • .:0).!fl~1;l:, .:.tLi?O):::::'!flUilt Jl<jjjjO)HL5t<

J: I) III*L, .:tc7)tk':--:>0)5'U.l:7.:>1lfI:.?til'.tLt-:.: C ~~-rtc7)"C";lV.:> 5.

iJI ;~'. ilJ

Explanation of Plate 76
Figs. 1-29; Ehmaniella burgessensis Rasetti.
1. A poorly preserved anaprotaspis, showing the large frontal lobe and the indistinct axis. x60.
2-4. Three metaprotaspides, showing the well demarked axis and the axial segments. 2, x62;
3, x62; 4, x50.
5-8. Paraprotaspides, showing the presence of the protopygidium. 5, x30; 6, x42; 7, x 26; 8,x37.
9-11,15,19-22. A few early meraspid cranidia and pygidia, showing the narrow anteriorborder and the pygidium with freely articulated segments and without a pygidial plate. 9,x23;10,x18;11, x21;15,x34;20,x30, 21,x26;22,x18.
12-14,23,26. Late meraspid cranidia and pygidia, showing the preglabellar field and wellankylosed pygidial plate lying behind the freely articulated thoracic segments. 12, x 20;
13, x22.5; 14, x13.5; 23, x15; 26, x20.
16-18,25,27-29. Several small and large-sized cranidia, showing the morphologic varieties, i.e.,the subquadrate and quadrate cranidia, and truncato-conical and short oblong glabellae. 16,x9; 17, x5.5; 18, x6.5; 25, x4.5; 27, x3.6; 28, x3.5; 29, x6.5.
24. A partly broken pygidium, showing the complete left margin. x5.5.

HU: Trilobite ontogeny

Plate 76

Trans. Proc. Palaeont. Soc. Japan, N. S., No. 135, pp. 401-414, pIs. 77-79, October 15, 1984

783. MIDDLE-LATE EOCENE PLANKTONIC FORAMINIFERAL FAUNAS FROMLIMESTONES OF THE SETOGAWA GROUP, CENTRAL JAPAN*
MASAKO IBARAKI
Geoscience Institute, Faculty of Science, Shizuoka University
Shizuoka 422, Japan

Abstract. Several thick limestone layers are exposed in the Setogawa terrain.
Well-preserved planktonic foraminifers were recovered from most of these limestone layers. Planktonic foraminifers consisting of a total of 23 species were discovered at seven limestone localities and in one mollusca-bearing sandstone of the
Setogawa Group. These limestones of the Setogawa Group are assignable to threedifferent horizons corresponding to Blow's zones of P. 12 to P., 13, P. 14 and P. 16,
and are dated to range from the Middle to Late Eocene.

Introduction

Several thick limestone layers in the Setogawa
terrain have been found to yield well-preserved
planktonic foraminifers after subjecting them tosome kind of treatments of acid. This is a reporton these planktonic foraminiferal faunas withwhich assignment of geologic age is attempted to
the limestones.

The Setogawa Group, which is extensively
exposed in the central part of Shizuoka Prefecture, Central Japan, has been regarded to be of
Paleogene age based on such sporadically occurring fossils as Discocylina (Ishii and Makino,1946), molluscs (Mizuno, 1956; Iwasaki andOno, 1977; Matsumoto, 1966, 1971), a Paleogene-type globorotaliid (Asano, 1962a), Eocene
nannoplankton (Honjo and Minoura, 1968;
Iijima et al., 1981), and Late Oligocene radiolarians (Iijima et al., 1981). However, some Early
to Middle Miocene radiolarians, have also beenreported from southern exposures of this group(Iijima et al., 1981). There have been few studies
on planktonic foraminifers from this groupmainly because of its strongly deformed geologic
structure and strongly indurated lithofacies.
Recently, the present author discovered
Middle Eocene planktonic foraminifers from amollusca-bearing calcareous sandstone and limestone bed slightly above the sandstone in. theSetogawa Group at Ashikubo (Ibaraki, 1983).

Acknowledgements
I am grateful to Professor Ryuichi Tsuchi of
our university for his kind advice about thegeology of the Setogawa Group and reviewing
the manuscript. Deepest appreciation is also due
to Professor Tsunemasa Saito of Yamagata
University who gave helpful suggestion about theidentification of planktonic foraminifers andread the manuscript.
Notes on the Stratigraphy of the
Setogawa Group with Speci~l Reference toLimestone Layers .
The Setogawa Group consists mainly ofalternati~g beds of sandsto~e and shale, which* Received June 17, 1983.
401

Masako !BARAK]

402

KUCHISENMJ\T A-X

7Q

1611
5 Ivvl

6

E22I
3 1ZI

4

z§

1m

4 km

SHIZUOKA

Text-fig. 1. Index and location map of limestone layers in the Set ogawa Group.
(mainly after Sameshima (1960) and Tsuchi et al. (1973) )1. Mikura Group (or Shimanto Group), 2. Setogawa Group, 3. limestone, 4. Oigawa
Group, 5. Ryuso Group, 6. terrace deposit, 7. sampling locality.

783. Planktonic Foraminifera from Setogawa Groupare more than 1000m in thickness, and is frequently intercalated with chert, limestone,
basaltic lavas, and pyroclastic and ultrabasic
rocks. This group exhibits strongly folded
structure with a general NE-SW structural trend.
The group has been classified stratigraphicallyinto three fonnations; namely, Ichinose, Takisawa
and Tentokuji in upward sequence by Chitani(1931), Makiyama (1963) and Tokuoka (1964).
However, Ono (1973), Tokuyama (1974), andSugiyama and Shimokawa (1981) divided it into
three fonnations, Sakasagawa, Takisawa andTentokuji (or Yoshizu).
Several thick limestone layers, which areexposed in various localities, have been includedin the Takisawa Fonnation by most of theseauthors, though some limestones were consideredby Wada (1976) to belong to the lower part of
the group, and by Iijima et al. (1981) to beintercalations at various horizons within thegroup.
The distribution of these limestone layers isshown in Fig. 1, largely on the basis of geologicalmaps of Shizuoka Prefecture (Sameshima (1960)
and Tsuchi et al. (1973». Typical exposuresof these limestone layers occur from north tosouth at Kuchisenmata, Kamisuke, Yokoyama,
Ushizuma, Ashikubo, Ubume, Odatara, Utsunoya,
Okabe, Tachisawa, and Chibasan.
Sampling and Treatment of Materials
Samples of limestone were collected from theabove-mentioned typical outcropping areas, andat each locality about ten samples representing
slightly different limestone lithologies werecollected for the examination of planktonic
foraminifers.
Rocks were crushed into a small pebble sizeand soaked in a 3% solution of either hydrochloric acid, or fonnic acid for several hours.
Materials separated from the rock surface werethen washed through a 200 mesh screen. In thisway, a few identifiable specimens of planktonic
foraminifers can be obtained from some of theselimestones. During the course of acid treatment,
solution was refreshed several times until a403

considerable amount of foraminiferal specimens
were recovered. Planktonic foraminifers of about
30-200 individuals thus obtained were pickedup from the residue and were examined withbinocular microscope. It is interesting to notethat planktonic foraminifers from these limestone are hardly defonned.
The present author was able to obtain planktonic foraminifers from most of the abovementioned limestones and discussion of theseforaminifers are given, for the sake of convenience, under the locality name of typical exposures of the limestones. These are: Kuchisenmata,
Yokoyama, Ashikubo, Utsunoya, Megurisawa,
Tachisawa and Chibasan.
Planktonic Foraminifers and their Geologic Ages
Planktonic foraminifers from seven limestones
and one mollusca-bearing sandstone of the
Setogawa Group consist of 23 species in total
and their frequencies are shown in Table 1.
Stratigraphic ranges to each species are based
mainly on Blow (1969, 1979).
Ashikubo Limestone: As previously stated(Ibaraki, 1983), a mollusca-bearing calcareous
sandstone at Ashikubo yielded such planktonic
foraminifers as Acarinina punctocarinata andSubbotina frontosa boweri, which range from
Zone P. 10 to P. 11 of Blow's zonal scheme, andSubbotina pseudoeocaena whose range spansfrom Zone P. 11 to P. 13. The mollusca-bearing
horizon is, therefore, assigned to Zone P. 11
of an early Middle Eocene age. A limestone
occurring a little above the mollusca-bearing
horizon at Ashikubo was reexamined for planktonic foraminiferal content by taking additional
samples. As a result, Subbotina bakeri andSubbotina inaequispira both of which range from
Zone P. 8 to P. 13 and Subbotinapseudoeocaena,
as mentioned above, were commonly recovered.
No specimen of such species as Subbotina
frontosa boweri and Acarinina punctocarinata,
whose ranges are limited to Zone P. 10 to P. 11,
could be found. Therefore, this limestone is mostprobably assignable to the Middle Eocene Zone
P. 12 to P. 13, slightly younger than the mol-

Masako !BARAK!

404

Table 1.
Occurrences of planktonic foraminifers from limestones and mollusca-bearing
sandstone of the Setogawa Group.
1. Kuchisenmata, 2. Ashikubo, 3. Yokoyama, 4. Odatara, 5. Utsunoya, 6. Megurisawa,
7. Chibasan, 8. Tachisawa, 9. mollusca-bearing sandstone at Ashikubo.
Specific name

Loc.

1

Acarinina boudreauxi Fleisher
Acarinina coalingensis (Cushman & Hanna) .... .
Acarinina pseudotopilensis Subbotina . . . . . . . . .
Acarinina punctocarinata Fleisher . . . . . . . . . . .
Chiloguembelina cubensis (Palmer) . . . . . . . . . .
Globigerina garavisi Bermudez . . . . . . . . . . . . . .
Globigerina officinalis Subbotina . . . . . . . . . . . .
Globigerina praebulloides praebulloides Blow ... .
Globigerina pera Todd . . . . . . . . . . . . . . . . . . .
Globigerinatheka index index (Finlay) . . . . . . . .
Globigerinita echinata echinata (Bolli) ....... .
Globigerinita globiformis Blow & Banner ..... .
Globorotalia insolita Jenkins . . . . . . . . . . . . . . .
Globorotalia spinulosa Cushman . . . . . . . . . . . .
Globorotaloides suteri Bolli . . . . . . . . . . . . . . .
Muricoglobigerina senni (Beckmann) . . . . . . . . .
Pseudohastigerina micra (Cole) . . . . . . . . . . . .. R
Subbotina bakeri (Cole) . . . . . . . . . . . . . . . . . .
Subbotina frontosa boweri (Bolli) . . . . . . . . . . .
Subbotina inaequispira (Subbotina) . . . . . . . . .. R
Subbotina linaperta (Finlay) . . . . . . . . . . . . . .. C
Subbotina pseudoeocaena (Subbotina) . . . . . . .. C
Truncorotaloides collactea (Finlay) ... . . . . . . .

2

3

4

5

6

7

8

9
R
R
R
A

R

R

C

C

C

A
A

C

A

C

A

C

R

C

A R

C
C

R

R

C
C

R

C

C

C
C

R

C

R
C

C

C

C

C

R

A
A

C
A
C
R

C

A

C

C

A

C
A

C

R

C

C

Frequency of occurrence: R. 1-2; C. 3-9; A. over 10 specimens.

lusca-bearing horizon.
Kuchisenmata Limestone: This limestone islocated at the northernmost locality among thestudied limestones of the Setogawa Group. It
is a bedded limestone of about 30m in thickness.
Although planktonic foraminifers are scarce,
Subbotina inaequispira and Subbotina pseudoeocaena were recovered from this locality. Since
this species composition resembles that of the
Ashikubo Limestone, these limestones are likely
to be of a comparable age.
Yokoyama Limestone: Discocyclina sp. wasreported from this limestone (Ishii and Makino,1946). The limestone is about 30m thick andcontains abundant planktonic foraminifers. As

specimens of Truncorotaloides collactea (Zone
P. 10 to P. 14), Muricoglobigerina senni (Zone
P. 8 to P. 14) and Globigerina pera (Zone P. 14
to P. 21) were commonly found, this limestone
can be assigned to Zone P. 14 of the latest
Middle Eocene age. The extinction of Muricoglobigerina senni, which is known in Zone P. 15
after Blow (1979), has been examined by
Toumarkine (1978) and Keller (1983) at the topof Zone P. 14.
Utsunoya Limestone at Odatara and at
Utsunoya: The distribution of this limestone
extends in the area west of Shizuoka City from
Ubume via Odatara to Utsunoya and Okabe.
It is siliceous one, 40-80m thick and exhibits

783. Planktonic Foraminifera from Setogawa Groupa dark gray color. At Odatara only three species
were recovered. They are Chiloguembelina
cubensis (Zone P. 13 to P. 22) and Globigerina
officinalis (Zone P. 14 to P. 21). The locality of
Utsunoya yielded specimens of Truncorotaloides
collactea (Zone P. 10 to P. 14) and Globigerina
pera (Zone P. 14 to P. 21). The limestone is thus
correlated with Zone P. 14 of the latest Middle
Eocene age.
Megurisawa Limestone: Some small limestonelenses occur scatteringly near Megurisawa northof Yaizu. They are dark gray silty limestones ofabout 5m in thickness. From one of the lenses,
Truncorotaloides collactea and Globigerina officinalis, were obtained, suggesting the latest
Middle Eocene Zone P. 14 age for this limestone
lens.
Chibasan Limestone: This limestone is exposed to the northwest of Chibasan and this is
the westernmost outcrop of the limestones
studied from the Setogawa Group. It is a darkgray silty limestone of about 10m in thickness.
As the limestone yields Globigerina pera and
Muricoglobigerina senni, it is also assigned toZone P. 14 of the latest Middle Eocene age.
Tachisawa Limestone: This limestone crops
out at a locality a little east of the Utsunoya
Limestone. Planktonic foraminifers recovered
include Globigerina praebulloides praebulloides(Zone P. 16 to P. 17), Globigerinatheka index
index (Zone P. 11 to P. 16) and Subbotina
linaperta (Zone P. 4 to P. 16). This limestone is,therefore, assigned to Zone P. 16 of a Late
Eocene age.
In summary, planktonic foraminifers from thelimestones of the Setogawa Group establish
three different age assignment covering a Middle
to Late Eocene interval (Fig. 2); the Ashikubo
and Kuchisenmata Limestones belonging toZone P. 12 to P. 13, the Yokoyama, Utsunoya,
Megurisawa and Chibasan Limestones belonging
to Zone P. 14, and the Tachisawa Limestonebelonging to Zone P. 16. It seems, therefore, thatgeologic ages of the limestones of the Setogawa
Group, except for the southeasternmost one,become younger in a general northwest-tosoutheast direction.

405

The Middle Eocene pianktonic foraminiferal
faunas in Japan have been reported by Asano(1962b) from the Kyoragi Formation and otherbeds in Amakusa Island, and by Saito (1962)
from the Nummulites-bearing Tuff and someother rocks in Hahajima Island. These faunasbear some resemblance to those of the Setogawa
Group. The fauna of the Kyoragi Formation
includes Subbotina frontosa boweri (reported
as Globigerina bowen), which is one of age
diagnostic species of the mollusca-bearing sandstone at Ashikubo assigned to Zone P. 11. The
Hahajima Island fauna contains such species
as Truncorotaloides collactea (reported as
Globigerina collactea) and Muricoglobigrina senni(reported as Sphaeroidinellopsis sennz) , both ofwhich are found in the Yokoyama Limestone
assigned to Zone P. 14.
Recently, Keller (1983) has pointed out threemajor faunal changes of planktonic foraminifers
during Middle to Late Eocene, which indicate
cooling episodes, respectively. The ages of thelimestones of the Setogawa Group are, however,corresponding just to warmer intervals prior tothose cooling episodes.
Systematic Description of Diagnostic Species
Family Globorotaliidae
Genus Acarinina Subbotina, 1953
Acarinina punctocarinata Fleisher, 1974
PI. 77, Figs. 1a-c, 2b

Acarinina punctocarinata Fleisher, 1974, p. 1014,
pI. 3, figs. 4-8.

This species was originally described byFleisher, based on materials obtained from Hole
220, core 12, section 5, 7D-72cm, DSDP, Leg.
23.
Fleisher (1974) placed this species under the
genus Acarinina, on the basis of its external formand coarsely punctate character of the pseudocarina. The most characteristic feature of thespecies is its distinct and thickened pseudocarina
consisting of coalesced pseudospines along theperipheral margin and extending over a short

406

Masako !BARAK!
Maor--soga Group_
Kakegawa Group

N.ll

PLlOCENE

N.19
N.18

w

N.17

Sagara Group

I-

~

N.16
N. 1 5

10

w
Z
UJ

N.14

w
~

N.D

::;

N.12
N.l0

o

U

N. 9

::;

N. 8

o

Ryuso Group
::;
0::

20

N. 5

..:
UJ

N. "

P.22
UJ
UJ

Z
UJ

30

I-

..:

P.21

oJ

U

o
lJ
:::;
o

c:
"
""
o
"o~ o""" '"""oS'"c:o.::. .5"o
.5"

P.20

:::i

.<:

P.19

.Q

0::

..:
UJ

Q,

P.18

f--+--l P. 17
UJ

I-

..:
...J

P.16

P.I1l

~

P.13

o

UJ

o

Z

::;

UJ

U

P.12
P.ll

oUJ

P.l0

>-

50

oJ
"

«UJ

.Q
.Q

P.15

40

t,)

o

e Yokoyama Ls.

.Q
.Q
::l

IU

til

§'!----------lJ-----------

"

til

.~

Q,

.:;'"
0'

"
.5"
.5"
(5

.Q
.Q
:l

til

~

'Cl" Ashikubo LS.

~_ ~s~i~~~~~~~i,~_-s~~

t t

p. 9

P. 3
P. 7

1-_1--1 P. 6
UJ

Z

UJ

U

o

UJ

oJ

;;:

P.
UJ

Ic(

P."

oJ

P. 3

60

Text-fig 2. Chronologie positions of limestones of the Setogawa Group.
Vertical ranges and occurrences of age diagnostic planktonic foraminifers arealso indicated.
The Paleogene time scale is that given by Hardenbol and Berggren (1978) andthat of the Neogene is given by Tsuchi et al. (1981)

783. Planktonic Foraminifera from Setogawa Groupdistance along dorsal intercameral sutures; test
typically subquadrate, a low trochospire, withfour or five chambers in the final whorl; chambers broadly wedge-shaped in ventral side view.
The genus Acarinina was first recognized by
Subbotina (1953) as that was distinguishable
from Globigerina and Globorotalia in having
an inflated Globigerina-like chamber without aperipheral keel. Recent authors accept this genus
to represent those species ranging in age from
Paleocene to Middle Eocene. Most of the species
possess a broadly planoconvex test with pseudo·carina.
According to Fleisher (1974), this species has
a limited stratigraphic range from Zone P. 10 toP. 11 in the lower Middle Eocene. The species
occurs commonly in the mollusca-bearing sandstone at Ashikubo.
Genus Truncorotaloides Bronnimann and
Bermudez, 1953

407

Family Globigerinidae
Genus Globigerina d'Orbigny, 1826
Globigerina officinalis Subbotina, 1953

PI. 77, Figs. 4a, cGlobigerina officinalis Subbotina, 1953, p. 87,
pI. 11, figs. 1-7.

According to Subbotina (1953), one of thecharacteristic features of this species is the shapeand size of the last hemispherical chamber which
may occupy as much as one half of the total
volume of the test. Test small, a low trochospire
being composed of three tightly coiled whorls.
The last whorl has four chambers which increase
rapidly in size as added and are clearly delimited
from each other by a deep suture. The species
occurs commonly in most of the studied limestones of the Setogawa Group.

Truncorotaloides collactea (Finlay, 1939)

Globigerina praebulloides praebulloides Blow,
1959

PI. 78, Fig. 6a

PI. 77, Figs. 5a, b

Globorotalia collactea Finlay, 1939, p. 327,
pI. 29, figs. 164-165.
Globigerina co llac tea (Finlay). Bronnimann,
1952, p. 13-14, pI. 1, figs. 13-15; Bolli,
1957, p. 72, pI. 15, figs. 21-23; Saito, 1962,
p. 216, pI. 32, figs. 12a-c.
Acarinina rotundimarginata Subbotina, 1953,
p. 234, pI. 25, figs. 1-3.
Truncorotaloides collactea (Finlay). Jenkins,
1971, p. 134, pI. 14, figs. 402-407.

Globigerina praebulloides Blow, 1959, p. 180181, pI. 8, figs. 47a--c, pI. 9, fig. 48.
Globigerina praebulloides praebulloides Blow.
Blow and Banner, 1962, p. 92, figs. O-Q.

This species was first described as belonging
to the genus Globorotalia. Afterward, it wasplaced in the genus Globigerina or sometimes
in the genus Truncorotaloides. Recent authors
place this species in the genus Truncorotaloides(Jenkins, 1971; Fleisher, 1974; Berggren, 1976).
The species is characterized by having fivehispid to weakly spinose chambers in the final
whorl, which are almost equal in size. The species
has been reported from the Nummulites-bearing
Tuff in Hahajima (Saito, 1962).

This species is the ancestral form of Globigerina bulloides d'Orbigny (Banner and Blow,
1959), being characterized by its four chambersin the last whorl; test subtrapezoidal in outline,
and bears a low-arched aperture with a thinrim-like lip, being different from Globigerina
bulloides d'Orbigny.
The species has a long stratigraphic range
from the upper Eocene to Middle Miocene andhas been reported from many other localities inJapan.
Globigerina pera Todd, 1957

PI. 78, Figs. la, CGlobigerina pera Todd, 1957, p. 301, pI. 70, figs.
10-11.

Masako !BARAK!

408

This species is characterized by having threechambers in the last whorl, being triangular in
the outline of test, and having a supplementarychamber which extends from the peripheryonto the umbilicus. The species resembles
Catapsydrax dissimilis. However, the distinction
between these two species lies in the shape of
supplementary chamber. In Catapsydrax dissimilis, it is like a bridge over the umbilicus andhas an opening on both sides. In the present
species, it is like a pocket which has only one
opening.
Genus Globigerinatheka Bronnimann, 1952
Globigerinatheka index index (Finlay, 1939)
PI. 78, Fig. 2a
Globigerinoides index Finlay, 1939. p. 125,
pI. 14, figs. 85-88.
Globigerapsis index (Finlay). Bolli, 1957, p. 165,
pI. 36, figs. 14-18; Blow and Banner, 1962,
p. 124-125, pI. 15, figs. g--h; Saito, 1962,
p. 221, pI. 32, figs. 9-10.
Globigerinatheka (Globigerapsis) index index(Finlay). Jenkins, 1971, p. 187-188, pI. 22,
figs. 641-645.
Globigerinatheka index index (Finlay). Bolli,
1972, p. 124, figs. 51-57,63-64, pI. 1, figs.
1-4,6-7.
This species was first described under the
genus Globigerinoides from the Middle Eocene of
New Zealand. In 1957, Bolli, Loeblich andTappan discriminated a new genus Globigerapsis
from Globigerinatheka Bronnimann on accountof the lack of a small angular bullae covering thesecondary apertures in the latter genus. In 1970,
Proto Decima and Bolli included Globigerapsis
in the genus Globigerinatheka. This species ischaracterised by having three spherical chambers
in final whorl and more deeply incised sutures.
It has also been reported from the Eocene of
Hahajima (Saito, 1962).
Genus Globigerinita Bronnimann, 1951
Globigerinita globiformis Blow and Banner, 1962
PI. 78, Figs. 3a, cGlobigerinita globiformis Blow and Banner,
1962. p. 108-109, pI. 14, figs. S-U.
Test globose, tightly coiled a low trochospire,
having four chambers in the last whorl. This
species is characterized by its umbilicus andprimary aperture which are completely coveredby a broad inflated bulla. The bulla is strongly
vaulted on the ventral side.
Genus Muricoglobigerina Blow, 1979
Muricoglobigerina senni (Beckmann, 1953)
PI. 78, Figs. 4a, b
Sphaeroidinella senni Beckmann, 1953, p.394395, pI. 26, figs. 2-4.
Globigerina senni (Beckmann). Bolli, 1957, p.
163, pI. 35, figs. 10-12.
Sphaeroidinellopsis senni (Beckmann). Saito,
1962, p. 218, pI. 34, figs. 3-5.
Muricoglobigerina senni (Beckmann). Blow,
1979, p. 1131, pI. 131, figs. 7-9; pI. 142, figs.
7-9, pI. 146, figs. 9-10, pI. 165, fig. 8,
pI. 236, figs. 1-4.

Explanation of Plate 77
a: umbilical view, b: dorsal view, c: side viewFigs. la, b, c; 2b. Acarinina punctocarinata Fleisher
Loc. mollusca-bearing sandstone at Ashikubo. la, b, c, x 270; 2b x 200
Figs. 3a, c. Chiloguembelina cubensis (Palmer)
Loc. Tachisawa L.s. 3a, c. x 300
Figs. 4a, c. Globigerina officinalis Subbotina
Loc. Yokoyama L.s. 4a, c x 180
Figs. 5a, b. Globigerina praebulloides praebulloides Blow
Loc. Tachisawa L.s. 5a, b x 115

!BARAK!: Planktonic Foraminifera from Setogawa

lb

/

I

'"

Plate 77

783. Planktonic Foraminifera from Setogawa Group

This species was originally described under the
genus Sphaeroidinella. In 1957, Bolli placed it
in Globigerina because of the absence of sutural
supplementary apertures and chamber flange.
Saito (1962) placed it in the genus Sphaeroidinellopsis, because it has a well developed crenulate
flange along apertural margins and because
Banner and Blow (1959) established a new genus
Sphaeroidinellopsis which is distinct from
Sphaeroidinella by the absence of supplementary
sutural apertures. Afterwards, Blow (1979)
placed it in the new genus Muricoglobigerina by
its characteristic muricate wall. Here present
author adopts Blow's concept of the genus
Muricoglobigerina.
This species has a very tightly-coiled test
showing an almost globular to elongated globularglobigerine appearance. The last whorl has
four chambers which increase rapidly in size as
added. Under the microscope, the surface of thetest has a coated appearance reminiscent of
Sphaeroidinella or Sphaeroidinellopsis. The species has been reported from the Eocene of
Hahajima (Saito, 1962).
Genus Pseudohastigerina Banner and Blow, 1959
Pseudohastigerina micra (Cole, 1927)

PI. 78, Figs. 5a, cNonion micrus Cole, 1927, p. 22, pI. 5, fig. 12.
Globigerinel/a micra (Cole). Subbotina, 1953, p.
122, pI. 8, figs. 16a-b, 17.
Hastigerina micra (Cole). Bolli, 1957, p. 161,
pI. 35, figs. 1-2.
Pseudohastigerina micra (Cole). Banner andBlow, 1959, p. 19-20, figs. 4g-i, Saito andBe, 1964, p. 704, fig. 2; Berggren et aI., 1967,
p. 271, fig. 9.
Globanomariina micra (Cole). Loeblich andTappan, 1964, p. C655, fig. 531, nos. 5-8.

This species was originally described as
Nonion micrus. Planispirally coiled planktonic
foraminifers are known in the Cretaceous,
Tertiary and also Recent. Early authors haveassigned planispiral species to such genera as
Globigerinella Cushman, 1927 and HastigerinaThomson, 1876. The genus Pseudohastigerina409

was erected by Banner and Blow (1959), and wasplaced in the subfamily Planomalinae. Loeblichand Tappan (1964) considered Pseudohastigerina
to be a junior synonym of Globanomalina
Haque, 1956, and placed it in the subfamily
Hastigerinae. Berggren et al. (1967) discussed theevolution of early members of the genus Pseudohastigerina from the ancestral Globorotalia
champmani and placed it in the subfamily
Hastigerinae. Planispirally coiled Paleogene planktonic foraminifers have mostly been includedin the genus Pseudohastigerina. Recent authors
accept Pseudohastigerina as the valid genus forthis species.
Test involute, bilaterally symmetrical; withsix or seven chambers in the last whorl which
rapidly increase in as added; sutures depressed,
initially almost radial, and it becomes increasingly curved in the younger part of test; aperture,
a low interiomarginal equatorial arch, extending
along the base of apertural face and embracing
an earlier whorl, with lip and partial flanges.
The species occurs commonly in most of thelimestones of the Setogawa Group.
According to Stainforth et al. (1975), Pseudohastigerina micra is relatively rare in the Middle
to Late Eocene assemblages of tropical andsubtropical areas where species diversity is high.
However, it may be a dominant form in Eocene
higher latitudes assemblages and in Oligocene
assemblages of both higher and lower latitudes.
Genus Subbotina Brotzen and Pozaryska, 1961
Subbotina frontosa boweri (Bolli, 1957)

PI. 79, Figs. la, 2b, 3a
Globigerina frontosa Subbotina, 1953, p. 84, pI.
12, figs. 3-7.
Globigerina boweri Bolli, 1957, p. 163, pI. 36,
figs. 1-2.
Subbotina frontosa boweri (Bolli). Blow, 1979,
p. 1266, pI. 175, figs. 7-9, pI. 179, fig. 9, pI.
184, figs. 8-9.

This species was first described as belonging
to the genus Globigerina from the basal Middle Eocene of northern Caucasus. After that,

Masako !BARAK!

410

Brotzen and Pozaryska (1961) recognized thegenus Subbotina separate from the genus Globigerina d'Orbigny (1826) on account of its
reticulate surface. Afterwards, Jenkins (1971)
accept it as a subgenus of Globigerina. Recent
authors, however, have accepted the genus
Subbotina as a valid name (Fleisher, 1974;
Mckeel and Lipps, 1975; Blow, 1979).
Test subquadrate; final whorl composedof three strongly inflated chambers, the lastchamber is hemispherical and is readily distinguishable from others by its exceptionallylarge size and characteristic shape; aperture large,
with arched lip opening into umbilicus. The
species occurs commonly in the mollusca-bearing
sandstone at Ashikubo.
Subbotina inaequispira (Subbotina, 1953)

PI. 79, Figs. 4a, 5a, b
Globigerina inaequispira Subbotina, 1953, p. 6970, pI. 6, figs. 1-4.
Subbotina inaequispira (Subbotina). Blow, 1979,
p. 1272, pI. 151, figs. 5-7, pI. 163, figs. 410, pI. 177, figs. 3, pI. 180, figs. 1-7, pI. 185,
fig. 9, pI. 186, fig. 1, pI. 191, fig. 7.

This species was originaly described as belonging to the genus G/obigerina. Test low
trochospiral, four chambers in the final whorl,with an arrangement of chambers same as that in
the genus Globigerinella, aperture small and low

arched; surface finely cancellate.
Subbotina linaperta (Finlay, 1939)

PI. 79, Figs. 6a, 7a, b
G/obigerina linaperta Finlay, 1939, p. 125, pI.
13, figs. 54-57.
Globigerina (Subbotina) linaperta Finlay. Jenkins,
1971, p. 162, pI. 18, figs. 551-554.
Subbotina linaperta (Finlay). Blow, 1979, p.
1276, pI. 91, fig. 8, pI. 124, fig. 9, pI. 158,
fig. 8, pI. 160, figs. 6-8, pI. 177, figs. 4-6,
pI. 240, figs. 5-6.

This species was originally described under
the genus Globigerina. Test with cancellate wall
surface; the last whorl generally composed ofthree and a half subglobular compressed chambers which increase rapidly in size as added; thefinal chamber is variable in size, but it is generally larger than the penultimate one. Apertureis low and large with a distinct lip. The species
resembles Subbotina frontosa boweri, but theformer is distinguished by its distinctive lip andcompressed chamber. The species has a longstratigraphic range from Zone P. 4 to P. 16
according to Blow (1979). It has been reported
from Paleogene sequences of Amakusa (Asano,
1962b) and Hahajima (Saito, 1962).
Subbotina pseudoeocaena (Subbotina, 1953)

PI. 79, Fig. 8a

Explanation of Plate 78
a: umbilical view, b: dorsal view, c: side viewFigs. la, c. Globigerina pera Todd
Loc. Yokoyama L.s. la, c x 120
Fig. 2a. Globigerinatheka index index (Finlay)
Loc. Tachisawa L.s. 2a x 23{)
Figs. 3a, c. Globigerinita globiiormis Blow and BannerLoc. Tachisawa L.s. 3a, c x 180
Figs. 4a, b. Muricoglobigerina senni (Beckmann)
Loc. Yokoyama L.s. 4a & b, same sample, 4a, b x 190
Figs. 5a, c. Pseudohastigerina micra (Cole)
Loc. Yokoyama L.s. 5a, c x 170
Fig. 6a. Truncorotaloides col/actea (Finlay)
Loc. Yokoyama L.s. 6a x 340

!BARAK!: Planktonic Foraminifera from Setogawa

Plate 786a

783. Planktonic Foraminifera from Setogawa Group
Globigerina pseudoeocaena Subbotina, 1953, p.
66, pI. 4, fig. 9.
Globigerina pseudoeocaena var. pseudoeocaena
Subbotina, 1953, p. 66, pI. 4, fig. 9, pI. 5,
figs. 1-2.
Subbotina pseudoeocaena (Subbotina). Blow,
1979, p. 1279, pI. 187, figs. 8-9.

This species was first described as belonging
to the genus Globigerina. Test large, final whorlwith four chambers, surface finely cancellate.
The species superficially similar to Subbotina inaequispira, as suggested by Blow (1979) who
considered the latter to be the ancestral form.
Both species are, however, dinstinguishable by
the size and arrangements of four chambers in
the last whorl.
Morphotypes referable to Subbotina pseudoeocaena appear in a horizon assignable to Zone
P. 11 and disappear in Zone P. 13 (Blow, 1979).
This species is reported for the first time fromJapan.
Family Heterohelicidae
Genus Chiloguembelina Loeblich and Tappan,
1957
Chiloguembelina cubensis (Palmer, 1934)
PI. 77, Figs. 3a, cGuembelina cubensis Palmer, 1934.
Chiloguembelina cubensis (Palmer). Beckmann,
1957, p. 89, fig. 14, nos. 5-8.

This species is characterized by having globular chambers which are biserially arranged.
Specimens of this species were recoveredfrom limestones at Odatara, Megurisawa andTachisawa, which are very small in size and aretriangular in test form with eleven chambers.
They have fine perforations on the surface.
Recently, this species has been reported from
Oligocene sequences in some localities in Japan(Kaiho, 1981; Tsuchi et al., 1983).
References
Asano, K. (1962a): Japanese Paleogene from theview-point of foraminifera with descriptions

411

of several species. Tohoku Uniu. Inst. Geol.
Pal. Contr. no. 57, p. 1-32.
- - (1962b): Tertiary Globigerinids from Kyushu, Japan. Tohoku Uniu., Sci. Rep., ser. 2,
Spec. Vol. no. 5, p. 49-65, pI. 19-23.
Banner, F. T. and Blow, W. H. (1959): Theclassification and stratigraphical distributionof the Globigerinaceae. Palaeontology, vol.
2, p. 1-27, pI. 1-3.
Beckmann, J. P. (1953): Die Foraminiferen der
Oceanic Formation (Eocaen-Oligocaen) von
Barbados, KI. Antillen. Eclogae Geol. Heluet.,vol. 46, p. 302-412, pI. 16-30.
- - (1957): Chiloguembelina Loeblich and Tappan and related Foraminifera from the lower
Tertiary of Trinidad, B.W.I. U.S. Natl.
Museum, Bull. 215, p. 83-96, 21pI.
Berggren, W. A. (1976): Atlas of Palaeogene
planktonic foraminifera. Some species of
the genera, Subbotina, Planorotaloides,
Morozouella, Acarinina and Truncorotaloides. Oceanic Micropalaeontology, vol. 1,
p. 205-265, pI. 1-12.
- - , Olsson, R. K. and Reyment, R. A. (1967):
Origin and development of the foraminiferal
genus Pseudohastigerina Banner and Blow,
1959. Micropaleontology, vol. 13, p. 265288, 1pI.
Blow, W. H. (1959): Age correlation, and biostratigraphy of the upper Tocuyo (San
Lorenzo) and Pozon Formation, eastern
Falcon, Venezuela. Am. Paleont. Bull., vol.
39, p. 67-251, pI. 6-9.
--(1969): Late Middle Eocene to Recent
planktonic foraminiferal biostratigraphy. In t.
Cont. Plankt. Microfossils, 1st Proc., In
Bronnimann, P. and Renz, H. H. (eds.),
Leiden (Brill), vol. 1, p. 199-422, pI. 1-54.
--(1979): The Cainozoic Globigerinida. Part 1,
II, section 1, 2, and Atlas. Leiden (Brill),p. 1-1413, pI. 1-264.
- - and Banner, F. T. (1962): The Mid-Tertiary(Upper Eocene-Aquitanian) Globigerinaceae.
In Eames, F. E., Banner, F. T., Blow, W. H.
and Clark, W. J., eds., Fundamentals of MidTertiary stratigraphical correlation. Cambridge Univ. Press. p. 61-151, pI. 8-17.
Bolli, H. M., (1957): Planktonic foraminiferafrom the Eocene Navet and San Fernando
Formations of Trinidad, B.W.I. U.S. Natl.
Museum Bull. 215, p. 61-81, pI. 15-20.

412

Masako !BARAKI--(1972): The genus Globigerinatheka Bronniman. Jour. Form. Research. vol. 2, p. 109136, 7pl.
- - , Loeblich, A. R. and Tappan, H. (1957):
Planktonic foraminiferal families Hantkeninidae, Orbulinidae, Globorotaliidae, andGlobotruncanidae. U.S. Natl. Museum Bull.,
215, p. 3-50, pI. 1-11.
Bronnimann, P. (1952): Trinidad Paleocene andlower Eocene Globigerinidae. Am. Paleont.
Bull., vol. 34, p. 1-34, pI. 1-3.
- - and Bermudez, P. J. (1953): Truncorota·
loides, a new foraminiferal genus from the
Eocene of Trinidad, B.W.I. Jour. Paleontology, vol. 27, p. 817-820, pI. 87.
Brotzen, F. and Pozaryska, K. (1961): Foraminiferes du Paleocene et de l'Eocene inferieur
en Pologne septentrionale; remarques paleogeographiques. Rev. Micropaleontologie, vol.
4, p. 155-166, 4pI.
Chitani, K. (1931): Geological map "Shizuoka"
with explanatory text, 1:75,000. Geol.
Surv. Japan.
Cole, W. S. (1927): A foraminiferal fauna fromthe Guayabal formation in Mexico. Am.
Paleontology, Bulls. vol. 14, no. 51, 46p,
5pl.
Finlay, H. J. (1939): New Zealand foraminifera;
key species in stratigraphy, no. 3. Royal
Soc. New Zealand Trans., vol. 69, p. 309-

329, pI. 24-29.
Fleisher, R. (1974): Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea
deep sea drilling project, Leg 23A. Initial
Repts. Deep Sea Drilling Project, vol. 23,
Washington. (U.S. Government Printing
Office). p. 1001-1072, 21pl.
Hardenbol, J. and Berggren, W. A. (1978): A new
Paleogene numerical time scale. In Cohee,
G. V. et al. eds., The Geologic Time Scale,Studies in Geology, no. 6, A.A.P.G., p. 213234.
Honjo, S. and Minoura, N. (1968): Discoasterbarbadiensis Tan Sin Hok and the geologic
age of the Setogawa Group. Proc. Japan
Acad., 44, p. 165-169.
Ibaraki, M. (1983): Occurrences of Middle
Eocene planktonic foraminifers in molluscabearing horizon and limestone of theTakisawa Formation, the Setogawa Group.
Jour. Geol. Soc. Japan. vol. 89, no. 1, p. 5759.
Iijima, A., Matsumoto, R. and Watanabe, Y.
(1981): Geology and siliceous deposits in
the Tertiary Setogawa Terrain of Shizuoka,
central Honshu. Jour. Fac. Sci., Univ.
Tokyo, sec. II, vol. 20, no. 3, p. 241-276.
Ishii, M. and Makino, T. (1946): On the Dis·
cocyclina from the Setogawa Series. Jour.
Geol. Soc. Japan, vol. 52, p. 610-612.

Explanation of Plate 79
a: umbilical view, b: dorsal view, c: side viewFig. 1a. Subbotina frontosa boweri (Bolli)
Loc. mollusca-bearing sandstone at Ashikubo
Fig. 2b. Subbotina frontosa boweri (Bolli)
Loc. mollusca-bearing sandstone at Ashikubo
Fig. 3a. Subbotina frontosa boweri (Bolli)
Loc. mollusca-bearing sandstone at Ashikubo
Fig. 4a. Subbotina inaequispira (Subbotina)
Loc. mollusca-bearing sandstone at Ashikubo
Figs. 5a, b. Subbotina inaequispira (Subbotina)
Loc. mollusca-bearing sandstone at Ashikubo
Fig. 6a. Subbotina linaperta (Finlay)
Loc. mollusca-bearing sandstone at Ashikubo
Figs. 7a, b. Subbotina linaperta (Finlay)
Loc. Yokoyama L.s. 7a, b x 220
Fig. 8a. Subbotina pseudoeocaena (Subbotina)
Loc. mollusca-bearing sandstone at Ashikubo

1a x 190
2b x 200
3a x 1704a x 210
5a, b x 130
6a x 1708a x 250

IBARAKI: Planktonic Foraminifera from Setogawa

Plate 79

783.

Planktonic Foraminifera from Setogawa Group

Iwasaki, Y. and Ono, S. (1977): A molluscan
assemblages of the Setogawa Group. Trans.
Proc. Palaeont. Soc. Japan, N.S., no. 106,
p.106-12I.
Jenkins, D. G. (1971): New Zealand Cenozoic
planktonic foraminifera. New Zealand Geol.
Survey Paleont. Bull., 42, 278p, 23pl.
Kaiho, K. (1981): Paleogene planktonic foraminifera in Hokkaido, especially on the
Poronai, Utsunai and Nuibetsu Formations.
Geol. Soc. Japan, 88th Ann. Meet., Abst.,
p.263.
Keller, G. (1983): Biochronology and paleoclimatic implications of Middle Eocene to
Oligocene planktic foraminiferal faunas.
Mar. Mieropaleontol., vol. 7, p. 463-486.
Loeblich, A. R. and Tappan, H. (1957): Planktonic foraminifera of Paleocene and early
Eocene age from the Gulf and Atlantic
coastal plains. U.S. Natl. Museum Bull. 215,
p. 173-198, pI. 40-64.
and - - - (1964): Sarcodina, chiefly"Thecamoebians" and Foraminiferida. In
Moore, R. C., ed., Treatise on Invertebrate
Paleontology. Protista 2, vol. 2, p. C511C900, figs. 400-653.
Makiyama, J. (1963): Geological map ofKakegawa district with explanatory text,
1: 50,000. Geol. Surv. Japan.
Matsumoto, E. (1966): Geology of the Palaeogene and lower Neogene formations in thelower course of River Ooigawa, Shizuoka
Prefecture, central Japan. Mem. Coli. Sci.,
Kyoto Univ., B, vol. 31, no. 2, p. 95-112.
--(1971): Oligocene molluscs from the Setogawa Group in central Japan. Bull. Natl. Sci.
Mus., Tokyo, vol. 14, no. 4, p. 661-669.
Mckeel, D. R. and Lipps, J. H. (1975): Eocene
and Oligocene planktonic foraminifera from
central and southern Oregon Coast Range.
Jour. Fora. Res., vol. 5, p. 249-269, pI. 1-

5.
Mizuno, A. (1956): A preliminary note on themegafaunal zone of the Paleogene in northwestern Kyushu, Japan. (For correlation of
the Paleogene formations in Japan). Bull.
Geol. Surv. Japan, vol. 7, no. 6, p. 25-34.
Ono, S. (1973): Slaty cleavages in the Paleogene
Setogawa Group in central Japan. Jour. Fae.
Sci. Univ. Tokyo, sec. II, vol. 18, p. 431454.

413

Palmer, D. K. (1934): The foraminiferal genus
Guembelina in the Tertiary Cuba. Mem. Soc.
Cubana, His. Nat., vol. 8, p. 73-76.
Proto Decima, F. and Bolli, H. M. (1970):
Evolution and variability of Orbulinoides
beekmanni (Saito). Eclogae Geol. Helvet.,vol. 63, p. 883-905, 4pl.
Saito, T. (1962): Eocene planktonic foraminiferafrom Hahajima (Hillsbrough Island). Trans.
Proc. Palaeont. Soc. Japan, n. ser., no. 45,
p. 209-225, pI. 32-34.
- - and Be, A. W. H. (1964): Planktonic foraminifera from the American Oligocene. Science, vol. 145, p. 702-705.
Sameshima, T. (1960): Picritic basalt in the
Paleogene formation in central Japan. Rep.
Fac. Lib. Art Sci., Shizuoka Univ., vol. 3,
no. 1, p. 77-80.
Stainforth, R. M., Lamb, J. L., Luterbacher,
H. 0., Beard, J. H. and Jeffords, R. M.
(1975): Cenozoic planktonic foraminiferal
zonation and characteristics of index forms.
Univ. Kansas Paleontol. Contrib., 62, 425p,
213 figs.
Subbotina, N. N. (1953): Iskopaemye foraminifery SSSR; Globigerinidae, Hankeninidae i
Globorotaliidae [Fossil foraminifers of the
USSR; Globigerinidae, Hantkenidae, andGloborotaliidae] : Yeses, Neft. NauchnoIssled, Geol.-Ravzed. Inst. Trudy, n. ser.,no. 76, 296p, 41pls.
--(1971): Fossil Foraminifera of the USSR
Globigerinidae, Hantkeninidae and Globorotaliidae: London and Wellingborough, Collet's Ltd., 321p, 40pl. [Translated by E.
Lees from Russian text of 1953]
Sugiyama, Y. and Shimokawa, K. (1981): A
paleogeographic study of the Paleogene
Setogawa Group, Shizuoka Prefecture, central Japan. Jour. Geol. Soc. Japan, vol. 87,
no. 7, p. 439-456.
Todd, R. (1957): Geology of Saipan, Mariana
Islands; Smaller foraminifera. pt. 3, Paleontology. U. S. Geol. Survey, Prof. Paper,
280-H, p. 265-320, pI. 64-93.
Tokuoka, T. (1964): Preliminary report on the
Cenozoic Setogawa and Oigawa Groups inthe central part of Shizuoka Prefecture,
Japan. Jour. Geol. Soc. Japan, vol. 70,
no. 820, p. I-II.
Tokuyama, A. (1974): Paleogene systems (Seto-Masako IBARAKI

414

Japan (1981): Bio- and chronostratigraphic
correlation of Neogene sequences in theJapanese Islands. In Tsuchi, R. ed., Neogeneof Japan - Its biostratigraphy and chronology, IGCP 114 National Working Group ofJapan, Shizuoka, p. 91-104.
- - , Shuto, T. and Ibaraki, M. (1983): Geologic
ages of the Ashiya Group and the Ashiya
molluscan Fauna as determined by planktonic foraminifera. Geol. Soc. Japan, 90th
Ann. Meet., Abst., p. 125.
Wada, N. (1976): Geology of the Abe-g!lwa
district, Shizuoka Prefecture. Jour. Geol.
Soc. Japan, vol. 82, p. 581-593.

gawa terrain). In Tsuchi, R. ed., Geology of
Shizuoka Prefecture, Shizuoka Prefecture,p.27-34.
Toumarkine, M. (1978): Planktonic foraminiferal
biostratigraphy of the Paleogene of sites
360 to 364 and the Neogene of sites 362A,
363, and 364 Leg. 40. Initial Repts. DeepSea Drilling Project, vol. 40, Washington(U.S.A. Government Printing Office), p.
679-721.
Tsuchi, R. ed. (1973): Geological map of Shizuoka Prefecture, 1:200,000, Shizuoka Prefecture.
and IGCP 114 National Working Group of

Set ogawa IiJ5J1I, Sakasagawa ~JlI. Takisawa l'IffiR. Tentokuji "7C00l1f. Yoshizu ifi~. Kuchisenmata JJ fllll:R. Ashikubo Jr.~{Jit Utsunoya "¥it /~. Megurisawa }ID!iR, Tachisawa ftiR, Chibasan
T~JlJ, Odatara *t', Ubume f£/,(, Kamisuke J:Jj;IJ. Okabe IlliJtlil. Ushizuma L:f~i'JiJ5JII~llfl7)15w(:WJliJ·t;,i£1±I Lt.:q:.· ~Wliltl~tltl7)i~~ft~:fL!l:l.llf: if.!iJ5J11J1llfl;:'I1J:<jl~-t 7.:> fiJiJ(!GJliJ;a- <~tlff vn, 7.:> • .:: h t;, 17) fjliJ(:W I;: 11, ~:fL!l:l.tJ: cl7)ill'Itft:fi~~tr.::c iJ;%1 t;,h -n ,t.:iJ;, :fi1iJ('tH*iJ· t;, +m!l:l.~7tmt-t 7.:> .:: c iJ;trfiJ· L <, P.lJfI'::' J: 7.:>1&~1'::' cc£-,-n't.:.

c4'@, .:: h t;,l7)fjliJ(:W~Ji[NU t.:11!1!ftM"t'M,1I-t 7.:> .:: I'::' J: I). ~b/Jb-Cf*ffl7) J: \, 'l-¥~M:~.fL!l:l. ~ 9 tt!! ..~iJ· t;, H 23m!1fr 7.:> .:: iJ; "t'Ji~f*. JJ filJI9l:151iJ(!5'17) "i> 17)11 Blow (1969,

*

c

n.:.

*

(q:.Wliltlffrilt), WtJlJ· "¥i'iI!/ ~·}ID!iR· T~JlJ:fiIiJ(!5'I7)"i>17)11 P. 14<q:.Wliltlffrilt), ftiR:fiIiJ(!617) i:, 17) 11 P. 16<~Wliltlffr tit) ~jf;-t.
-t 17),~-*, i'JiJ5 JIIlmllft'::'11q:.ltFJiJ· i?~JVJiltlffr~tI'::'bt.: 7.:> 3 JI~I7):fiIiJ(:ftJl~ 1!;tr::. c iJ;fJij

1979) 17) P. 12-13

i?iJ·CtJ:-,t.:.

'*

**~T

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 135, pp. 415-426, October 15,1984

784. URANIUM-SERIES AGE OF THE RIUKIU LIMESTONE ON
HATERUMA ISLAND, SOUTHWESTERN RYUKYUS*
AKIO OMURA
Department of Earth Sciences, Faculty of Science, Kanazawa University

Abstract. Uranium-series analyses of seventy-four coral samples imply that the
Pleistocene Riukiu Limestone (Hanzawa, 1935) on Hateruma, Ryukyu Islands,
were formed during at least four stages of high sea stand, two interstadials (ca. 81
and 103 ka B.P., respectively) and two interglacials (the last and penultimate ones).
The oldest coral date was 300:!:j?ka obtained from a Porites sample which wascollected at a locality of about 33 m above the sea. Maybe this date is suggestivethat the coral reef has already formed at the time of an another high sea stand(correlative to the stage 9 of the marine oxygen isotope record) in the place where
the island is at present. The tidal flat around the coast of the island is likely to havebeen built since the last thousands years. The Riukiu Limestone on Hateruma isthus correlative with some of Pleistocene uplifted coral reefs on Barbados (Bender
et al., 1979), New Guinea (Bloom et al., 1974) and Kikai (Konishi et al., 1974)
dated previously, and the tidal flat limestone with the Raised Coral Reef Limestone
on Kikai (Ota et al., 1978) and with the reef complex I on the Huon Peninsula,
New Guinea (Bloom et al., 1974).
Among marine terraces which were divided into eight steps ('1'1 through T8) by
Ota et al. (1982), T2 and lower five terraces (T4 to T8) are inferred to be erosionalin origin, based on the results of 230 Th/234 U age determination of corals which werecollected on the same surface of the terraces. Ota et al. (1982) documented that theformer shoreline of each terrace shows progressive westward tilting. The maximum
uplift rate of approximate 0.3 m/ka is calculated in the eastern part of the island,assuming the constant rate of tectonic uplift and a sea level 6 m higher of thepresent one at the time of T3 terrace formation (ca. 128 ka B.P.). Accordingly,
Hateruma is considered to have been situated tectonically in the compressive field
since the last interglacial.

59.5 m above the sea, and staircase morphology
is typically developed on it. The basement rock
exposed at very limited small area on the island isdark bluish-gray colored siltstone, ranging in age
from Upper Miocene to Pleistocene, which has
been named the Shimajiri Group. This stratum isoverlain by the reefy limestone which is a few totens meters in thickness and covers almost allisland.
After the initiative work of Hanzawa (1935)
who divided into two time-stratigraphic units,

Introduction
The island of Hateruma is located in Lat.

24°02.4' to 24°04.0' N. and 123°45.1' to123° 48.6' E., southwestern end of Ryukyu
Islands. It is roughly elliptical in shape having alength of about 5.9 km and a width of 2.9 km at
its widest part and has an area of about 15 km 2 .
The island is flat as a whole, its highest point is* Received Aug. 1, 1983;
read Jan. 23, 1983 at Tokyo
415

416

Akio OMURA

Pleistocene Riukiu Limestone and Holocene
Raised Coral Reef Limestone, the limestone on
Hateruma was classified into four morphostratigraphic units by Kawana and Oshiro (1978).
They estimated by the 14 C method that theirlatest unit, the Surface IV, was formed approximately 30 ka (kilo anno = 1,000 years) B.P. By
using the non-destructive 226 Ra/ 238 U dating
technique, Konishi (1980) verified the firstradiometric date of Middle Pleistocene from theraised coral reefs in the Ryukyu Islands area, for
two coral samples from the Surface I and II of
Kawana and Oshiro (1978), and revised the age
estimation of Kawana and Oshiro for the Surface
IV to be the last interglacial (ca. 120 to 130 ka
B.P.). Emergent marine terraces on the island wasrecently subdivided into eight steps, T1 throughT8, by Ota et al. (1982). They inferred, from thewidth of terraces, height of terrace riser, thickness and facies of limestone and presence ofspecific raised coral reef surface features, that
only two terraces, T1 and T3, are constructive
raised coral reefs formed in association withrising sea level, and that the other steps, T2 andT4 to T8, are erosional in origin. In addition,
their conclusions founded on the results of the
230 Th/ 234 U dating for seven corals were that T3
was formed during the last interglacial and T1
during the preceding one. In the process of thisstudy, the author has found and preliminarily
reported the existence of limestone units whichwere formed during the times of two interstadials, ca. 80 and 102 ka B.P., respectively(Omura, 1983).
As stated above, age determination of thecoralline limestone on Hateruma seems to havebeen under way little by little. The reliable
radiometric dates, however, are definitely insufficient for age assignments of the entire limestone on the island and for correlation with those
ip othe,r areas. The main aim of the present work
is to gain enough numbers of 230 ThF34 U coral
dates from Hateruma, as the most fundamental
data, .in order to discuss the tectonic history of
the island and sea level change and relate them tovarious Pleistocene events in other areas.

SamplesSeventy-four samples of hermatypic corals,
which included ten genera, were chosen for
dating purpose mainly from the reefy limestone
on Hateruma Island, Southwestern Ryukyus.
Among them, sixty-nine samples were takenfrom the Riukiu Limestone which was considered to be Pleistocene in age by Hanzawa(1935), and five from the limestone forming thepresent tidal flat around the coast of the island.
Table 1 lists numbers, taxonomy and elevation of
the samples analyzed in this study, and theterrace number of their localities, which were
defined by Ota et al. (1982). The localities of all
samples are plotted on the map showing theirclassification of geomorphic surface (Text-fig. 1).
Natural exposures of the Riukiu Limestone isvery limited in number on the island except thecoastal area, and therefore man-made outcrops
like quarries, road-cuts and gullies, or even somegigantic masses of limestone dug in the cause ofsoil amendment were used effectively for fieldobservation. However, they are not yet sufficient
to examine geologically the Riukiu Limestone on
Hateruma, based on the detailed litho- and biofacies analyses.
In the present study, coral samples for datingwere collected as equably as possible from all of
the morphostratigraphic units of Ota et al.
(1982). Number of samples collected from each
unit are shown in a figure (Text-fig. 2) mentioned
later. Mode of occurrence and mineralogicalnature of fossil corals were examined very carefully in the processes of searching coral samples
suitable for dating. Most of samples for datingwere selected, with some exceptions, from largesized (more than 50 cm in diameter) coral colonies which were still in their original positionof growth. One sample (A0131) was fair-sized(about 70 cm in diameter) but was apparently
included as a gravel in non-reef facies (probably fore-reef facies) of limestone. Six samples(A0096, A0097, A0116, A0138, Aoi60 and
A0162) could not be decided whether they arein situ or not. The field test for diagenetic altera-784. Age of Riukiu Limestone on Hateruma

417

Table 1. List of the fossil coral samples from the Riukiu Limestone on Hateruma.
(KK-series samples were collected by Prof. K. Konishi of the Kanazawa Univ., OHB-series by
Prof. Y. Ota of the Yokohama National Univ., Dr. N. Hori of the Hiroshima Univ. ~nd Prof.
A. L. Bloom of the Cornell Univ., and others were collected by the author himself. See Textfig. 1 for the terrace num ber.)Code Number

A0020
AOO2l
A0022
A0024
A0025
A0026
A0028
A0035
A0064
A0065
A0066
A0067
A0068
A0069
A0070
A0094
A0095
AOO96
A0097
A0098
A0099
AOI00
AOI0l
AOI03
AOI04
AOI05
AOI06
AOI07
AOI08
AOI09
A0112
A0113
A0114
A0115
A0116
A0117
A0118
A0119
A0120
A0121
A0122
A0123
A0124
A0125
A0126
A0127
A0128
A0129
AOl30
A0131
A0132
A0133
A0134
A0135
A0136
AOl37
AOl38
A0153
A0154
A0155
A0156
A0157
A0158
A0159
A0160
A0161
A0162
A0163
A0164
A0165
A0166
A0167
A0168
A0169

Sample Number

KK7807071-2
KK7807071-3
KK7807053-1
KK7807054-2
KK7807051-2
KK7807084-1
KK780706-2
81-11-28-1
OHB801103-1
OHB801103-2
OHB801103-1
OHB801104-2
OHB801104-8
OHB801105-3
OHB801105-7
81-11-30-2
81-12-5-2
81-12-5-4
81-12-5-5
81-12-2-1
81-12-2-2
81-12-2-3
81-12-2-8
81-11-30-3
81-12-5-1
81-12-5-3
81-12-4-4
81-12-6-1
81-12-4-7
81-12-1-2
81-12-2-5
81-12-3-2
81-.12-3-4
81-12-3-5
81-12-1-1A
81-11-29-1
81-11-29-7
81-11-30-5
81-12-4-9
81-11-30-8
81-12-1-3
81-12-5-6
81-12-2-4
81-12-2-7
81-12-2-9
81-11-29-5
81-11-29-6
81-11-30-4
81-12-1-5A
81-12-3-3
81-12-3-1
81-12-2-10
81-11-29-4
81-12-1-5B
81-11-29-3
81-12-2-6
81-12-4-1
81-11-30-6
81-11-30-7
81-11-30-9A
81-11-30-9B
81-12-1-4A
81-12-1~4B

81-11-30-1
81-11-30-11
81-11-29-2
81-12-1-1B
81-12-3-6
81-12-3-7
81-12-4-8
81-12-4-2
81-12-4-5
81-12-4-3
81-12-4-6

GeneraCYl2hastrea

Porites
Goniastrea
Porites

Porites
Porites
Goniastrea
Porites
Porites
Porites

Porites
Porites

Porites
Favites
Porites
Porites
Porites
Porites
Porites
Porites

CYl2hastrea
Favia
Porites
PoritesAcropora
Porites
Goniastrea
Goniastrea
Goniastrea
Goniastrea
Leptoria
Montipora
Porites
Goniastrea
Porites
Porites
Porites
Porites
Porites
PoritesMontiEora
Montastrea
Porites
Porites
Porites
Porites
Porites
PoritesMontastrea
Porites
Porites
Favites
PoritesMontiporaMontiEora
CYl2hastrea
PoritesFavia
Goniastrea
P1at:i9:yra
Porites
Goniastrea
Porites
PlatY9:yra
Porites
Goniastrea
Porites
Goniastrea
PoritesElevation

Terrace

10 m
10
43
13
9
8
48
48
30
20
33
48
15
5
20
24
23
10
10
19
19
22
15
24
20
18
0
14
11
0
34
0
0
3
35
12
3
1
43
5
3
2
3
4
3
4
7
4
2
7
26
8
8
3
11
32
48
3
3
4
4
4
4
0
35
12
35
3
5
11
48
7
48
7

VII
VII
II
VI
III
VII
III
III
II
I
V
VI
III
IV
IV
IV
IV
III
III
III
V
III
IV
IV
V
VI
II
VII
I
VII
VIII
V
V
V
V
VIII
V ?
VI ?
VIII
VI
V
VI
VII
III
V
VII
VI
VII
II
V
V
V
V
V
V
VII
VII
VII
VII
I
VII
I

VII

AkioOMURA

418

E3

Ikm
e:I

1= =11 [j]]]]11 Ed III ITIIJIV L::::::Jv ~VI I:::::WII !iiiU\\~~VIII
Text-fig. 1. Map showing the localities of fossil corals mentioned in this paper.
(Roman numerals from I to VIII in the legend denote the terrace number of Ota et al., 1982)
tion of a coral was to examine the existence ofthe secondary low-Mg calcite by the minute
observation under a magnifier and the staining
method using Feigl's solution. Ten genera listed
in Table 1 are almost representatives of corals in
reef facies of the Riukiu Limestone on Hateruma.
Porites was the most predominant genus of all,due to its abundance and well-preservation in
many exposures.
Uranium-Series Dating
Chemical and analytical procedures employedin uranium-series dating have been described
previously (Omura, 1976). The coral fragments
were mechanically cleaned, crushed into small(less than 5 mm in diameter) piecies, scrubbed
ultrasonically in distilled water, dried in a drying
furnace at low temperature (lower than 50°C),
and ground to a fine (less than 200 mesh) powder. The concentration of uranium and thorium
isotopes and the activity ratios of 234 U/238 U,

230 Th/ 232 Th and 230 Th/ 234 U were measured by
the alpha-spectrometry method, using a 4096
channels multi-channel pulse height analyzer
coupled with four systems of silicon solid-state
detectors. The Harwell spike solution of 232 U
and 228Th (Ivanovich and Warchal, 1981) wasused as a yield tracer to check the overall chemical yield of uranium and thorium isotopes. The
mineralogy of all specimens was examined withspecial care by X-ray diffraction analysis prior tothe chemical treatment.
Results of the isotopic measurements on
uranium and thorium are given in Table 2. The
quoted errors are standard deviations (one sigma)
derived from counting statistics.
Analyses of X-ray diffraction patterns provedthat no or only a trace to 2 - 3 % low-Mg calcite
was contained in all samples used here. Besides
the mineralogical composition, it must be known
whether the samples have been a closed systemwith respect to uranium and intermediate nuclides between 238U and 230Th.

784. Age of Riukiu Limestone on Hateruma
The possibility of post-mortem addition orloss of uranium is considered from the age
dependence of its concentration. There is, however, no systematic change in uranium concentration of the fossil corals with age (Table 2). It
may, therefore, be safely said that the coral
samples dated here have been closed system foruranium since the death of organisms. On theother hand, the 234 U/238 U activity ratios seem todecrease toward its secular equilibrium value of
1.00 with the ages of samples. This fact adds
support to the inference that closed system
respect to uranium isotopes has been held on
throughout their diagenetic history.
230 Th/234 U ages are calculated on the assumption that each sample was initially free of 230Th.
Such an assumption is supported by the observation that 232 Th concentrations in more than half
samples in the table do not exceed the lower
limit of detection (0.02 ppm). For the samples
in which measurable amount of 232Th was
detected, 232Th concentration is not much exceeding the limit, and furthermore the 230Th/
232 Th activity ratio is very much higher thanthose (1.4 to 3.0) in Ryukyuan present-day
corals (Omura, 1976).
The above evidences suggest that all of the
230 Th/234 U ages in Table 2 are fully reliable.
Age and Correlation of the Riukiu
Limestone on Hateruma
Barbados in the West Indies, the Huon Peninsula of New Guinea and Kikai in the Ryukyu
Islands can be listed as the three major type
localities for the Pleistocene coral reefs whichhave been chronologically studied by using theuranium-series dating techniques. The existenceof several interstadials at intervals of approximately 20 ka, following the last interglacial, havebeen clearly vindicated in those regions by
Bender et al. (1979), Bloom et al. (1974),Konishi
et al. (1974) and others. In this paragraph, I
attempt the age assignments of the Riukiu Limestone on Hateruma and the correlations of themwith the counterparts in such areas.
As above-mentioned, it was extremely diffi-

419

cult to investigate the Riukiu Limestone in detailall over the island of Hateruma, because of thelimited numbers of outcrops. That means thedifficulty in minute facies analyses of the Riukiu
Limestone which is overlaying the staircase
topography of this island. For this reason, thenature and size of each reef complex could not
be made clear in this study, although the Riukiu
Limestone on Hateruma is very likely to be acomposite of several reef complexes. Here,renaming the morphostratigraphic units definedby Ota et al. (1982) as Hateruma I, II, III, and soon, the ages of them are estimated and such units
are correlated with the Pleistocene uplifted coral
reefs reported from Barbados, Huon Peninsula
and Kikai.
The 230 Th/ 234 U dates which are younger than
the age (120 to 130 ka) of the last interglacial
were obtained for the first time from the Riukiu
Limestone on the other island than Kikai in the
Ryukyu Islands region (Table 2). The otherdates, except the oldest one in the table, arenearly equivalent to the ages of two interglacials
the last and penultimate ones. The oldest coral
date is 300~j? ka of A0066 sample which is a
Porites collected at a locality of about 33 m
above the sea. This date imply that the coral reef
has already been formed at that time in the place
where the island is at present. In comparison
with the ages of the coral reefs in above-mentioned areas, 230Th/234 U dates may be arranged
into five or possibly six groups as shown in Table
2, which are thousands years (younger than 10ka), approximately 70 to 90 (81 ± 3, in average)ka, 100 to 106 (103 ± 1) ka, 110 to 158 (128 ±7) ka, 190 to 260 (207 ± 3) ka, and 300 or moreka, respectively. In other words, the Pleistocene
Riukiu Limestone on Hateruma is considered tohave been formed during four or possibly fivestages, which include two interstadials, twointerglacials and possibly an another interglacialcorrelative to the stage 9 inferred from theisotope record of core V28-238 (Shackleton andOpdyke, 1973: Table 3).
Text-fig. 2 is a simplified topographic cross section in which eight steps of marine terraces developing on the island of Hateruma is schematically

"'"

I:\:)

Table 2.

Code Number

238oIsotopic composition and estimated ages of fossil corals from the Riukiu Limestone on Hateruma.

234

U
(ppm)

Isotope Concentration
232
UTh(dpm/g)
(ppm)

AOI09
A0114
A0113
AOI06
A0159

4.05 ± 0.04
2.93 ± 0.03
2.80 ± 0.03
2.70 ± 0.03
2.29 ± 0.04

3.44 ± 0.03
2.55 ± 0.03
2.39 ± 0.03
2.35 ± 0.03
1.92 ± 0.03

A0119
A0096
A0118
A0125
A0126
AOI08
A0153

2.88 ± 0.03
2.57 ± 0.03
2.81 ± 0.03
2.70 ± 0.03
2.53 ± 0.02
2.62 ± 0.03
2.72 ± 0.03

2.33 ± 0.03
2.12 ± 0.02
2.26 ± 0.02
2.24 ± 0.02
2.05 ± 0.02
2.18 ± 0.02
2.24 ± 0.02

A0124
AOI0l
A0157
A0094
A0127
A0129

2.84 ± 0.03
3.53 ± 0.03
2.63 ± 0.03
2.42 ± 0.02
2.82 ± 0.03
2.65 ± 0.03

A0130
A0021
A0133
A0097
A0158
A0020
AOI07
A0135
A0163
AOI03
A0165
A0095
A0024
A0123
A0115

2.74 ± 0.03
2.73 ± 0.05
2.62 ± 0.02
2.52 ± 0.02
2.63 ± 0.05
2.88 ± 0.06
2.78 ± 0.03
2.33 ± 0.03
2.74 ± 0.03
3.57 ± 0.03
2.80 ± 0.03
2.69 ± 0.03
2.65 ± 0.06
2.85 ± 0.03
2.46 ± 0.03

< 0.02

Activity
230
Th

234U/238U< 0.020.0266±0.0036< 0.02< 0.020.0314±0.0039

1.11 ± 0.02
1.02 ± 0.01
1.26 ± 0.02
1.27 ± 0.01
1.16 ± 0.01
1.25 ± 0.01
1.29 ± 0.02

1.09 ± 0.01
1.11 ± 0.01
1.08 ± 0.01
1.12 ± 0.01
1.09 ± 0.01
1.12 ± 0.01
1.11 ± 0.01

2.28 ± 0.03
2.63 ± 0.02
2.19 ± 0.04
1.98 ± 0.02
2.37 ± 0.03
2.22 ± 0.02

< 0.020.0409±0.0044
0.0206±0.0036< 0.02< 0.020.0526±0.0050

1.39 ± 0.02
1. 79 ± 0.02
1.39 ± 0.02
1.24 ± 0.01
1.50 ± 0.02
1.40 ± 0.02

1.08 ± 0.01
1.11 ± 0.01
1.13 ± 0.01
1.10 ± 0.01
1.12 ± 0.01
1.12 ± 0.01

2.22 ± 0.02
2.24 ± 0.04
2.11 ± 0.02
2.10 ± 0.02
2.19 ± 0.04
2.41 ± 0.05
2.34 ± 0.03
1. 91 ± 0.02
2.27 ± 0.02
2.93 ± 0.03
2.27 ± 0.02
2.23 ± 0.02
2.23 ± 0.05
2.37 ± 0.02
2.01 ± 0.02

< 0.02

1.43 ± 0.02
1.47 ± 0.03
1.37±0.04
1.38 ± 0.02
1.44 ± 0.02
1.60 ± 0.03
1.58 ± 0.02
1.28 ± 0.02
1.53 ± 0.02
1.97 ± 0.02
1.54 ± 0.02
1.53 ± 0.02
1. 54 ± 0.05
1.64 ± 0.02
1.41 ± 0.01

1.09 ± 0.01
1.10 ± 0.02
1.08 ± 0.01
1.12 ± 0.01
1.12 ± 0.02
1.12 ± 0.02
1.13 ± 0.01
1.10 ± 0.01
1.11 ± 0.02
1.10 ± 0.01
1.09 ± 0.01
1.11 ± 0.01
1.13 ± 0.02
1.12 ± 0.01
1.10 ± 0.01

< 0.020.0219±O.0035< 0.02< 0.020.0278±0.0070< 0.02< 0.020.0258±0.0034
0.0334±0.0057
0.0292±0.0033< 0.020.0200±0.0039< 0.020.0229±0.0035
0.0252±0.0039< 0.02< 0.02< 0.02EstimatedAge(ka)1.14 ± 0.01
1.17 ± 0.01
1.14 ± 0.01
1.17 ± 0.01
1.13 ± 0.02

< 0.02230 Th /234 U(dpm/g)0.0292±0.0016
0.0691±0.0031
0.0974±0.0030
0.116 ± 0.005
0.106 ± 0.004< 0.02

230Th /232 Th

Ratio

20.1±3.3

199 ± 27
171 ± 21183 ± 20281 ± 49
III ± 11221 ± 55
233 ± 30
199 ± 34
225 ± 25318 ± 61281 ± 43254 ± 400.00847±0.00046
0.0271±0.0012
0.0408±0.0013
O. 0492±0. 0022
0.0550±0.0022

0.92±0.05
3.0 ± 0.2
4.5 ± 0.2
5.5 ± 0.3
6.0 ± 0.5

0.475 ± 0.009
0.482 ± 0.008
0.555 ± 0.011
0.566 ± 0.009
0.564 ± 0.008
0.573 ± 0.009
0.574 ± 0.009

69 ± 271 ± 287 ± 389 ± 389 ± 291 ± 30.607 ± 0.011
0.616 ± 0.009
0.623 ± 0.011
0.623 ± 0.008
0.632 ± 0.012
0.631 ± 0.010

100 ± 3102 ± 3103 ± 3104 ± 3106 ± 4106 ± 30.644 ± 0.010
0.656 ± 0.019
0.652 ± 0.018
0.657 ± 0.012
0.660 ± 0.014
0.664 ± 0.017
0.675 ± 0.010
0.671 ± 0.011
O. 672 ± 0.012
0.675 ± 0.010
0.680 ± 0.011
0.686 ± 0.011
0.691 ± 0.027
0.693 ± 0.012
0.701 ± 0.011

110 ± 3112 ± 7112 ± 6113 ± 4114 ± 4115 ± 5118 ± 3118 ± 4118 ± 4119 ± 4121 ± 4122 ± 4123 ± 9124 ± 4128 ± 491 ± 3

~

;;:,-

o·
o

~

§
~

A0132
A0069
A0121
A0134
A0025
A0136
A0169
A0098
A0026
A0070
A0122
A0164
A0161
A0128
A0167
A0068
A0117
A0065
A0099
A0100

2.81 ± 0.03
2.71 ± 0.03
2.62 ± 0.03
2.78 ± 0.03
2.74 ± 0.08
2.53 ± 0.03
2.66 ± 0.03
2.72 ± 0.03
2.69 ± 0.05
2.80 ± 0.04
2.50 ± 0.03
2.60 ± 0.03
2.63 ± 0.03
2.21 ± 0.03
2.52 ± 0.03
2.76 ± 0.03
2.45 ± 0;03
2.64 ± 0.03
2.66 ± 0.02
2.76 ± 0.03

2.36 ± 0.03
2.28 ± 0.02
2.18 ± 0.02
2.31 ± 0.03
2.17 ± 0.06
2.12 ± 0.04
2.20 ± 0.03
2.24 ± 0.02
2.22 ± 0.04
2.29 ± 0.03
2.04 ± 0.02
2.12 ± 0.02
2.16 ± 0.02
1.83 ± 0.02
2.10 ± 0.02
2.27 ± 0.02
2.01 ± 0.02
2.14 ± 0.03
2.17 ± 0.02
2.20 ± 0.02

< 0.020.0362±0.0055< 0.02< 0.02< 0.02< 0.02< 0.02< 0.020.0243±0.0070< 0.020.0260±0.0034
0.0288±0.0048
0.0233±0.0041< 0.020.0347±0.0041< 0.020.0211±0.0029
0.0220±0.0030
0.0241±0.0032
0.0257±0.0037

1.13 ± 0.01
1.62 ± 0.03
1.54 ± 0.02
1. 65 ± 0.02
1.54 ± 0.02
1.53 ± 0.02
1.59 ± 0.02
1.61 ± 0.02
1.61 ± 0.04
1. 66 ± 0.02
1.48 ± 0.02
1.54 ± 0.02
1.96 ± 0.02
1.35 ± 0.02
1.57 ± 0.02
1. 71 ± 0.03
1. 52 ± 0.02
1. 65 ± 0.02
1.69 ± 0.02
1. 70 ± 0.02

1.13 ± 0.01
1.13 ± 0.01
1.11 ± 0.01
1.12 ± 0.01
1.06 ± 0.02
1.12 ± 0.01
1.11 ± 0.01
1.10 ± 0.01
1.10 ± 0.02
1.10 ± 0.01
1.10 ± 0.01
1.09 ± 0.01
1.10 ± 0.01
1.11 ± 0.01
1.11 ± 0.01
1.10 ± 0.01
1.10 ± 0.01
1.08 ± 0.01
1.09 ± 0.01
1.07 ± 0.01

A0154
A0112
A0105
A0155
A0131
A0116
A0028
A0104
A0137
A0162
A0067
A0166
A0156
A0035
A0022
A0168
A0064
A0120
A0138
A0160

3.35 ± 0.03
2.48 ± 0.03
3.45 ± 0.05
3.32 ± 0.03
3.02 ± 0.04
3.39 ± 0.04
2.65 ± 0.07
3.11 ± 0.04
2.65 ± 0.03
2.72 ± 0.03
2.73 ± 0.03
2.75 ± 0.03
2.79 ± 0.03
2.65 ± 0.06
2.56 ± 0.06
2.77 ± 0.03
2.57 ± 0.03
2.77 ± 0.03
2.94 ± 0.03
2.48 ± 0.03

2.73 ± 0.03
2.00 ± 0.02
2.83 ± 0.04
2.69 ± 0.03
2.38 ± 0.04
2.67 ± 0.03
2.20 ± 0.06
2.49 ± 0.03
2.17 ± 0.02
2.17 ± 0.02
2.15 ± 0.02
2.24 ± 0.02
2.25 ± 0.03
2.13 ± 0.05
2.06 ± 0.04
2.23 ± 0.03
2.06 ± 0.02
2.22 ± 0.02
2.35 ± 0.02
2.00 ± 0.02

0.0438±0.0050
0.0222±0.0029
0.0391±0.0044< 0.02< 0.020.0277±0.0031< 0.020.0332±0.0055< 0.02< 0.020.0229±0.0052< 0.02< 0.02
O. 0724±0. 0041
0.0246±0.0062< 0.02< 0.020.0233±0.0046< 0.020.0287±0.0037

2.30 ± 0.03
1.69 ± 0.02
2.40 ± 0.02
2.29 ± 0.02
2.02 ± 0.02
2.30 ± 0.02
1.92 ± 0.03
2.15 ± 0.03
1.89 ± 0.02
1.88 ± 0.02
1.87 ± 0.03
1.96 ± 0.02
1.97 ± 0.03
1. 87 ± 0.06
1.83 ± 0.04
1.99 ± 0.02
1.84 ± 0.02
1. 98 ± 0.03
2.12 ± 0.03
1. 85 ± 0.02

1.09 ± 0.01
1.08 ± 0.01
1.10 ± 0.01
1.09 ± 0.01
1.05 ± 0.01
1.06 ± 0.01
1.11 ± 0.02
1.07 ± 0.01
1.10 ± 0.01
1.07 ± 0.01
1.06 ± 0.01
1.09 ± 0.01
1. 08 ± 0.01
1.07 ± 0.03
1.08 ± 0.02
1.08 ± 0.01
1.08 ± 0.01
1.08 ± 0.01
1.07 ± 0.01
1.08 ± 0.01

A0066

2.50 ± 0.03

2.00 ± 0.02

0.0304±0.0070

1.91 ± 0.04

1.07 ± 0.01

0.705 ± 0.011
0.711 ± 0.014
0.708 ± 0.011
0.712 ± 0.012
0.709 ± 0.023
0.720 ± 0.012
0.719 ± 0.012
0.722 ± 0.011
0.725 ± 0.023
0.725 ± 0.019
0.724 ± 0.012
0.726 ± 0.013
0.732 ± 0.013
0.738 ± 0.013
0.747 ± 0.012
0.753 ± 0.015
0.756 ± 0.012
0.771 ± 0.012
0.779 ± 0.011
O. 77 5 ± 0.012

128 ± 4130 ± 5130 ± 4131 ± 5132 ± 8133 ± 5133 ± 5135 ± 4136 ± 9136 ± 7136 ± 5137 ± 5138 ± 5140 ± 5143 ± 5147 ± 6148 ± 5155 ± 5158 ± 5158 ± 5191 ± 8269 ± 35

0.844 ± 0.012
0.844 ± 0.012
0.850 ± 0.014
0.851 ± 0.012
0.853 ± 0.015
0.862 ± 0.012
0.873 ± 0.029
0.867 ± 0.016
0.872 ± 0.014
0.867 ± 0.013
0.870 ± 0.018
0.876 ± 0.013
0.876 ± 0.016
0.878 ± 0.033
0.888 ± 0.028
0.892 ± 0.015
0.893 ± 0.016
0.893 ± 0.016
0.901 ± 0.014
0.924 ± 0.014

192 ± 8194 ± 9196 ± 8201 +11 -10
207 ± 9208 +22 -18
208 +12 -11
208 +10 - 9
209 ± 10212 +14 -12
212 +10 - 9
214 +13 -11
217 +28 -22
223 +22 -20
226 +13 -12
227 +14 -13
227 +14 -13
235 +14 -13
256 +16 -14

262 ± 60

0.955 ± 0.022

300 +40 -31

187 ± 29276 ± 80237 ± 32
223 ± 37282 ± 50188 ± 22301 ± 41
312 ± 43291 ± 39277 ± 40
219
316
256

25
41
29

346 ± 39270 ± 44340 ± 77108 ± 26309 ± 77354 ± 69

~
~

~
o

-..
~

E"
;;,E"
t-<

~"

'"on

0;:l
o'"

;:l

~

c;:~
~
~

.,..
tv
f-'

Akio OMURA

422

Table 3. Stages and their ages when the uplifted
coral reefs on Hateruma were formed.
Stage

5 ?

Years B,P,N

I satope Stage(7)

8LOOO , 3,000(6 )

103,000 ' 1,000(35)

128,000' 7,000(20)

207,000 , 3,000(1 )

300,000 or mare..

-NI nlJroer of samples

after Shackleton and Opdyke (1973)

illustrated. In the text-figure, the terrace numbersof ota et ai. (1982) are given by using Roman
numerals from I to VIII and parenthesized figuresmean number of coral samples collected fromrespective terrace. The stripes drawn in boldstrokes over the cross section denote that the
samples assigned to each stage were collectedfrom the under terrace, and the portion drawn infine stripes that the corals alive during each stage
were not found so far. Namely, Text.fig. 2 showsthat the coral dates of the stage 4 were obtained
from the terraces I to VI, those of the stage 3
from III to VIII, those of the stage 2 from IV,
V and VIII, and those of the stage 1 from V, VI
and VIII. No coral date suggestive of Pleistocene
was found .from the limestone forming thepresent tidal flat around the coast of Hateruma.
The tidal flat is thus considered to have been
built since the last thousands years. It may be

Table 4. Correlation of the uplifted coral reefs on Hateruma with the counterparts reported from
Barbados, Huon Peninsula and Kikai.
(One and two star marks mean that the uplifted coral reefs in each area are defined as mor·
phostratigraphic and time-stratigraphic units, respectively.)
Barbados *Mesolella et al. (1969)and others

Huon Peninsula,
New Guinea **Ryukyu Islands
Kikai **

Hateruma *Bloom et al. (1974)
and others

Konishi et al. (1974)
and others

this paper

Reef Complex I(5 - 9 ka)

Raised Coral Reef
Limestone(2 - 7 ka)

Tidal Flat Limestone

Reef Complex II(28 - 29 ka)
Reef Complex Illb
(41 ka)Araki Limestone(35 - 45 ka)

Barbados o ?
(60 ka)Reef Complex IV(61 ka)Younger Member of
Riukiu Limestone(55 - 65 ka)

Barbados I(82 ka)Reef Complex V(85 ka)Barbados II(105 ka)

Reef Complex VI(107 ka)

Barbados III(127 ka)

Reef Complex VII(1l8 - 142 ka)

198, 220, 242, 268(ka)Middle Member of
Riukiu Limestone(80 - 100 ka)
Older Member of
Riukiu Limestone(120 - 130 ka)

Hateruma VIII
(81 ± 3 ka)
Hateruma IV(103 ± 1 ka)
Hateruma III(128 ± 7 ka)
Hateruma I(207 ± 3 ka)

Barbados X, XI
Barbados XII, XIII

(300 or more ka)
Barbados XIII

784. Age of Riukiu Limestone on Hateruma

ISTAGE I

423

ill

IT

(9 )

(4)

rn

OJ
< 10 ka(10)

Text-fig. 2. Schematic illustration of eight steps of marine terraces on Hateruma.
(Topographic cross-section is drawn not to scale. Roman numerals indicate the morphostratigraphic units of Ota et aI., 1982. Parenthesized figures mean number of coral samples dated. See
text for details.)
put in another way that the sea level has attained
at least up to the highest point among the localities of coral samples assigned to each stage. The
morphostratigraphic units on Hateruma areconclusively correlative, as summarized in Table
4, with the Holocene and Pleistocene coral reefs
reported from Barbados, Huon Peninsula andKikai, respectively.
The occurrence of corals dated to be older(for an example, 214~ti ka of A0156 sample)
from the lower terrace (the terrace V for the
sample) may suggest that the limestone ofyounger than the time of the last interglacial wasformed as a small-scaled fringing reef in thelimited parts and/or a very thin veneer. In either
case, the lower terraces of IV to VIII are very

likely to have been eroded since emerging ashore,because of no surface features peculiar to raisedcoral reef, narrowness of terrace and poor occurrence of coral heads. It may therefore be said
that the terraces on Hateruma are partly (onlyterraces I and III) constructive and partly (theother terraces) erosional in origin.
Sea Level and Tectonic History
The elevation of the terraces I through VIII
must involve at least two variables, the sea levelat the time of reef formation and the tectonic
uplift since then. In order to interpret thegeology and geomorphology of Hateruma interms of sea level and tectonic history, it is theAkio OMURA

424

Text-fig. 1 and that the paleosea level during theterrace III time (128 ± 7 ka B.P.) was plus 6 m
relative to the present datum (Bloom et ai., 1974;
and others), the uplift rate of Hateruma is
calculated to be 0.27 m/ka in eastern part ofthe island and 0.11 m/ka in western part, respectively. These values are an order of magnitude
lower than a value of 1 - 2 m/ka estimated forthe last interglacial emerged reef (Older Limestone Member of Riukiu Limestone: Konishi
et ai., 1974) on Kikai. Text-fig. 3 verfies such a
difference in neotectonic rate of vertical movement between the islands of Hateruma and Kikai.
In addition, the absence of the Holocene Raised
Coral Reef Limestone uplifted on the island like
Kikai also may support that the uplift rate ofHateruma is much lower than that of Kikai.
Konishi (1980) has previously pointed out agreat difference in the rate of neotectonic uplift
between the islands of Kikai and Hateruma, after

first consideration to settle the present altitudeof the paleosea level of the time when each reef
was formed. As stated above, it may be safely
said that the paleosea covered up the terraces
I and III during the last and preceding interglacials, respectively. Because the author could
not confirm the reef-crest elevation as yet, thepaleosea level is supposed here as a first-ordermodel to have attained up to the present elevation of the break in topographic surface, theboundary between the terraces II and III, during
the last interglacial.
Ota et ai. (1982) evaluated, by using a precesion altimeter, for the present elevation of thethen sea level to vary from 40 - 41 m in easternpart of the island to about 20 m in western part.
They concluded from this fact that the island of
Hateruma has been progressively tilting westwards. Assuming that uplift has been constant ineach block bounded by some faults as seen in
20

E

~

~

I

--

2

150

Q)

Q.

E

o

(f)

"D 100

.£>
o

o

c

o
o 50
>

Q)

GJ

50

100

150

230Th/ 234 U

Age

--

200
(ko)

250

300

Text-fig. 3. Comparison on elevation of dated corals from the Riukiu Limestone and uplift
rates between the islands of Kikai and Hateruma.
(1 and 2 show the samples collected on Kikai and Hateruma, respectively. Data on coral samples of
Kikai were referred from Konishi et. aI., 1974 and others, and unpublished dates also are plotted.
Parenthesized figures mean the uplift rate in unit of m/ka.)

784. Age of Riukiu Limestone on Hateruma

he evaluated the uplift rate of Hateruma to be so
low or even in the magnitude of practicallyalmost none. By the citation of the theory of
Uyeda and Kanamori (1979), he attributed thisdifference to the disparity in mode of subductionof the West Philippine Sea plate. Both Kikai and
Hateruma are the most trench ward islands in theCentral and Southwest Ryukyu blocks, respectively, which are bounded by the Miyako Depression. Depending on Konishi (1980), Kikai has
been uplifted rapidly and tilted towards the
Asian continent through compression arisen fromgently (25 0 - 35 0 in dipping angle of the WadatiBenioff zone) subsiding of the West Philippine
Sea plate as the "Chilean-type" of plate convergence by Uyeda and Kanamori (1979). On theother hand, the Southwest Ryukyu block inclusive of Hateruma sits next to a steeply dipping(55 0 - 65° in average and more at the lower tip)
Wadati-Benioff zone and is now in the tensile
field behind the frontal arc like the case of"Mariana-type" of plate convergence.
The resultant obtained in this study implies
that Hateruma has been situated tectonically inthe compressive field since the last interglacial.
Although the uplift rate of this island is undoubtedly lower than that of Kikai, its maximum
is comparable to the value estimated from one of
the standard traverses, the Christ Church traverse,
settled on Barbados by Bender et al. (1979).
Without the tectonic uplift of such an order, it
is hardly possible that the dates suggestive of
two interstadials after the last interglacial are
obtained from the fossil corals in the Riukiu
Limestone on Hateruma.
Acknowledgments
I am deeply indebted to Professors Kenji
Konishi, Kanazawa University, and Yoko Ota,
Yokohama National University, for furnishingan excellent opportunity for the study on
Hateruma Island. This work was partly supported by a Grant-in-Aid (no. 56540481) from
the Ministry of Education, Science and Culture.

425

References Cited
Bender, M. L., Fairbanks, R. G., Taylor, F.
W., Matthews, R. K., Goddard, J. G. andBroecker, W. S. (1979): Uranium-series
dating of the Pleistocene reef tracts ofBarbados, West Indies. Geol. Soc. Amer.
Bull., Part I, vol. 90, p. 577-594.
Bloom, A. L., Broecker, W. S., Chappell, J. M. A.,
Matthews, R. K. and Mesolella, K. J. (1974):
Quaternary sea level fluctuations on atectonic coast: new 230 Th/ 234 U dates fromthe Huon Peninsula, New Guinea. Quaternary Res., vol. 4, p. 185-205.
Hanzawa, S. (1935): Topography and geology of
the Riukiu Islands. Tohoku Univ., Sci. Rep.,
2nd Ser. (Geol.), vol. 17, p. 1-61.
Ivanovich, M. and Warchal, R. M. (1981): Reporton the second Intercomparison Projectworkshop, Harwell, 23 to 24 June 1980.
54 p., AERE-R 10044, Harwell, Oxfordshire.
Kawana, T. and Oshiro, I. (1978): Topography
and geology of Hateruma Island, Okinawa
Prefecture - with special reference to thelate coral reef deposits - (in Japanese withEnglish abstract). Geological Studies of the
Ryukyu Islands, vol. 3, p. 139-146.
Konishi, K., Omura, A. and Nakamichi, O.
(1974): Radiometric coral ages and sea level
records from the Late Quaternary reef
complexes of the Ryukyu Islands. Proc. 2ndInt. Coral Reef Symp., vol. 2, iJ. 595-613.
- - (1980): Diverse plate convergence as deduced from raised coral reefs since the lastinterglacial (in Japanese with English abstract). Quaternary Res. (Daiyonki-Kenkyu),
vol. 18, p. 241-250.
Mesolella, K. J., Matthews, R. K., Broecker, W. S.
and Thurber, D. L. (1969): The astronomical
theory of climatic change: Barbados data.
Jour. Geol., vol. 77, p. 250-274.
Omura, A. (1976): Thorium and protactinium
isotopes in some present-day hermatypiccorals and their implications to dating.
Trans. Proc. Palaeont. Soc. Japan, N.S., no.
101, p. 271-290.
--(1983): New information on radiometricages of fossil corals from the Hateruma
Island, Ryukyu Islands (in Japanese).

426

Akio OMURA
Quaternary Res. (Daiyonki-Kenkyu) , voL

22, p. 19-22.
Ota, Y., Machida, H., Hori, N., Konishi, K. andOmura, A. (1979): Holocene raised coral
reefs of Kikai-jima (Ryukyu Islands) - Anapproach to Holocene sea level study - (inJapanese with English abstract). Geogr. Rev.
Japan, voL 51, p. 109-130.
- - , Hori, N. and Omura, A. (1982): Age anddeformation of marine terraces of Hateruma
Island, Southwest Japan. Abstract of XI

INQUA Congress, Moscow, voL 2, p. 232.
Shackleton, N. J. and Opdyke, N. D. (1973):
Oxygen isotope and paleomagnetic stratigraphy of equatorial Pacific core V28-238:
oxygen isotope temperatures on a 10 5 and10 6 years time scale. Quaternary Res., voL
3, p. 39-55.
Uyeda, S. and Kanamori, H. (1979): Back-arc
opening and the mode of subduction. Jour.
Geophys. Res., voL 84, p. 1049-1061.

&~~Am.~~w~~~~~~aM~R:m.B~~~t~mm.~p,9~~~0t

t iliiWHJUH=-(li:ir"t-j 7.> &!m",9JiJ!~.5t.~~'t:·t=-0\' '-(, -t-~if3)jllJI~t\:~fl!.l (:::.>7'.» I=--t 7.> t.:.'d), 74@j~fi(tt1:-iT ~ ::"1I:~iJ'l? 2:J°Thj""'U ~Rilf1~:;j('d)t.:.. -t-~f.5*, *A~ mf.j(E~:'EHt ~1JTtit~
JtIl~4@)~~jifi.i#i\liltil (:}';:}';J:-t- 81,000 ~t 103,000 ~j)ij~2fi[~jljiJ",'7l<JtIlt, 12S,000 ~t 207,000 ~j)ij~ 2 @)~I["7)cJtfl) l=-if31lli: ~ nt..:':: t iJ:f]Ij l?iJ'IUJ: 0 t..:. *liIf'Jl:-e~ I?nt.:.~ti~ t ~It, 300, 000 ~~~: ~~~ ~ ...c.

.:: ~~(\';([I1i, J: 'HJ,j)ij~ (i?iilfdJf£1ffL;g!'ii*~ili:f*Jt7-.

7" -:; 9 t=-x-1.lt ~n7.» r.~7l<ltIll=-lJI.tE~ilJi!K1A~(j'l.1ITt=- -t-et=- -iT ~ ""Ii!¥.iJ:.lfJ!llt~ n'n ,t..:':: t~jf;I~ L"n';Q. i~Al'9;f'JRH1Il'1'X: vn, 7.>:P~r.iJ'I?tf<~~nt..: 5 Wq~-iT ~ ",'1I:EI1, \, 'fn

t 10,000 '*-tnT~if·i\: (920±50 '>f.-6,OOO±500 if.) ~;j; Lt..:. -ttJ:bt), ffl.f£JiJj~Jr.JI!ll~~1lX0 -Oei! L -(\, '7.>it}jWf-II~Ji, ~:t~T~lrijl-:'bt..: -" -C1f3!llt~n -C ~ t.:. t ~ t \, '.:t J: 5 •.:: ~ J: 51=-, &J!(~r.,1.ii',~.!i,t£j(E~'(':·~, fI~ -( /' r':\~')i!j(}) BarbaJos Ii!!, .=. "- - ""'.=. 7 Huon '11.·.~~Mm.~p,9~~HW~~~~~~.~~-iT/'~~K~Jt-t7.>.::t~~~K~0k.

1Hll:liiJ'~A*~~~.ht..:·tj-~""1l:fi~{F(\:il\ll~*,'i.I,IH-=.~t--j~, Ota et al. (1982) 1=-J:0(TI-TS) ~5"t::>, l:(.v:b'1?2f&:tl (T2) tT(.\l.~5f&: (T4-c8r,l:f-='klll~t~nt..:tlji!lltrl:1i-TS) Ii, fU'{ITfi t~;t 1?;jc7.>. ~ I? I-=', llZl?,i.llliif3$(j(J-'fad=-J: 0-C, *f&:fi:.M!lltlkf~l[3fLFJilrf:jJJr~*'d), *!1I;I):j'll)J "'f\:(i!fib L.. -C \" 7.> U.'i,jfiQ L..t..: • .tr jiil, Ji.z**r.,l))cj~H=-.lfJ!llt ~;jc t..:':: tiJ;Jit;;IE~.ht..: T3 ITfi~IlHn)U;jJ!.tt, ~£H!lJ!E!ltIJ(})~Jn£;to J: V:~H;'f~i1Iftl#~~ffl.f£J: I) 6 m
jfM'0t..:ti&:..E-t7.>':: tl=-J: I), *A<7)Jri.k~.li\))EJ.it'i, :t;:t;J:.:t 0.3m/1,000~·t~·I·:w~n7.>. tJ,J:~$~~~;t tl;b-lt 7.> t, ilJiJ\(ir,,1£',li, M:**r,,17l<WJtJ,I\If, illif1ll'~(~~t=-'i!Etrll~I=-:}';iJ'n-C~ktmbn7.>.

*M~.

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 135, pp. 427-444, pIs. 80, 81, October 15,1984

785. HEMIASTERID ECHINOIDS FROM THE UPPER CRETACEOUS OF JAPAN*
KEISAKU TANAKA
Geological Survey of Japan, Ibaraki 305

Abstract. In this paper selected eight species of Hemiaster from the Upper
Cretaceous of Japan are described. They are assigned to the subgenera Hemiaster(5 species), Leymeriaster (2 species) and Mecaster (1 species). Among them, one isnew, another is a hitherto described Japanese species, and some of the rest areprovisionally comparable with but distinct from certain foreign species, but I postpone to establish new taxa until more and better material is obtained. Some brief
remarks are given on the Hemiaster faunal aspect, the mode of occurrence and theinferred mode of life.

Introduction

Japan, and the rest are new to this country.
Thus, selected species of Hemiaster are to be
described in this paper.
The material for this study came from various
areas in Japan, from Hokkaido to Kyushu. The
areas concerned are as follows:
Kamisarufutsu area, Kitami Province, northern Hokkaido
Shimukappu area, Iburi Province, southern
Hokkaido
Urakawa area, Hidaka Province, southern
Hokkaido
Yuasa area, Wakayama Prefecture
Awaji Island, Hyogo Prefecture
Asan Mountain Range, Kagawa Prefecture
Uwajima area, Ehime Prefecture
Onogawa area, Oita Prefecture
Koshiki Islands, Kagoshima Prefecture
The repositories of the specimens describedhere are the Geological Survey of Japan, Tsukuba(GSJ) and the Yokosuka City Museum (YCM).
Before going further, I wish to express mysincere gratitude to Professor Emeritus Tatsuro
Matsumoto of Kyushu University for his valuablesuggestions and kindness in critical reading of themanuscript. I am also indebted to Dr. Ikuwo

Echinoid fossils are found in the Upper Cretaceous strata in many places of Japan, although
they are subordinate constituents of the Upper
Cretaceous marine fauna. Nevertheless, few
palaeontological investigations have been madeon them. In fact, only eight species belonging to
six genera have been described (Jimbo, 1894;
Lambert in Lambert and Thiery, 1924; Morishita,
1955, 1962; Saito, 1959; Nisiyama, 1966,
1968; Tanaka, 1984). Under these circumstances,
I have endeavoured to obtain by myself echinoid
specimens from various Upper Cretaceous
outcrops of this country. Meanwhile, echinoid
specimens collected by several other persons
have been supplied to me. Thus, a considerable
number of Upper Cretaceous echinoid specimens
have been assembled for the study. They are.
however, so poorly preserved that it is often
difficult to identify them at generic or evenfamily level. Anyhow, of the material examinedeight species belonging to the genus Hemiaster
have been identified. One of them is new, another is a previously described species from* Received August 6, 1983.
427

Keisaku TANAKA

428

Obata of the National Science Museum, Tokyofor his much help in studying the Museum specimens, and also to Dr. Yoji Teraoka of the Geological Survey of Japan, Professor Masahiro
Okubo of Shimane University and Dr. Yasumitsu
Kanie of the Yokosuka City Museum who kindly
showed me some valuable specimens for thisstudy. Finally my thanks are due to Mr. Yoshio
Masai of the Geological Survey of Japan forphotographing the specimens.
Systematic Descriptions
Order Spatangoida Claus, 1876
Suborder Hemiasterina Fischer, 1966
Family Hemiasteridae Clark, 1917
Genus Hemiaster Desor, 1847
Remarks: - The genus Hemiaster was classified into seven sections by Lambert and Thiery(1924) and into eight sections by Mortensen(1950). Later, Fischer (in Moore, ed., 1966)
raised these sections to the level of subgenera,
with some modification. In the frameworks ofclassification proposed by previous authors,
the division into subgenera is based largely on
shape of the test, depth of the frontal sinus,
flexuosity of the paired petals and on length
ratio of the anterior to the posterior petals.
Thus, the species described here are assigned
to the subgenera Hem ias ter, Leymeriaster andMecaster.

500 m south of Sakura-toge, Hiromi-cho, Kitauwa-gun, Ehime Prefecture, middle part of the
Oguwa Formation of Teraoka et al. (1980),
Shimanto Supergroup, Middle Turonian (colI.
Teraoka); GSJ. F6197, 6198 and 6199, represented by an internal and/or an external mould
respectively, from loco UF-8, Sakashitazu,
Uwajima City, Ehime Prefecture, Furushiroyama
Formation, Uwajima Group, Coniacian (colI.
Teraoka). One comparable specimen was also
examined: GSJ. F6062 from loco UF-68, about
500 m southeast of Tanikira, Hiromi-cho, Kitauwa-gun, Ehime Prefecture, middle part of the
Oguwa Formation, Middle Turonian (coil.
Teraoka).
Diagnosis: - Test small, roundly-cordate inoutline, shallowly emarginate in front, nearly as
long as wide, widest somewhat in front of the
midpoint, constricted behind, rather low; frontal
sinus wide, more or less deep, open towards theambitus with constant depth, forming a rather
broad and shallow notch at the anterior marginof the test, extending to the peristome. Aboral
surface rather evenly inflated, highest somewhat
behind the apical system, gradually sloping
anteriorly, abruptly truncated posteriorly, moreor less strongly inflated near the apical systemin the antero-Iateral interambulacral areas witha somewhat prominent median carina in the

Subgenus Hemiaster Desor, 1847
Hemiaster (Hemiaster) uwajimensis Morishita
PI. 80, Figs. 1-3; Text-fig. 1

1962. Hemiaster uwajimensis Morishita, Jour.
Earth Sci., Nagoya Univ., vol. 10, p. 113116, pI. 1, figs. 1-7.
1968. Hemiaster uwajimensis, Nisiyama, Palaeonto Soc. Japan, Special Papers, no. 13, p.
196, 197;pl. 18, figs. 2, 5,9 (1966, ibid.).

Material: - Four specimens are available:
GSJ. F6196A, B (A, internal mould; B, externalmould of aboral surface), from loco UF-65, about

lmm

~

lmm

L...---1

Text-fig. l. Hemiaster (Hemiaster)uwajimensis Morishita, GSJ. F6196. a,
Frontal ambulacrum. b, Left anterior
petal. c, Left posterior petal. d, Apicalsystem.

785.

Upper Cretaceous Hemiasterids

posterior interambulacral area; oral surface
flattish on the whole, depressed around theperistome, somewhat inflated in the plastronalregion. Apical system small, somewhat posterior,
ethmophract, with four gonopores; madreporite
extending as far back as to separate the posterior
genital plates, touching the posterior occularplates.
Frontal ambulacrum rather long and wide,
widening from the proximal to the middle partand from the middle to the distal passing withparallel sides, moderately sunken throughout
its length, subpetaloid; poriferous zones muchnarrower than half the width of the interporiferous zone; pores small, round; pores of each pairoblique, close together, separated by a distinct,
oblong and transverse granule.
Paired ambulacra broad, wider than thefrontal ambulacrum, widest at the middle, deeply
sunken, petaloid. Anterior paired petals rather
long, somewhat longer, more or less wider andmuch more divergent than the posterior, slightly
flexuous, somewhat closed distally, extending
about two-thirds the way to the margin; poriferous zones wider than the interporiferous; anterior zones slightly narrower than the posterior;pores slit-shaped, acuminated inwards, somewhat
longer in the outer row than in the inner row;
pores of each pair opposite, widely set. Posterior
paired petals rather short, 0.55-0.65 as longas and somewhat narrower than the anterior
petals, diverging from each other at an angle alittle more than half as large as in the anterior,sligh tly flexuous, closed distally, extending
about halfway to the margin; poriferous zones
nearly equal in width, wider than the interporiferous zones; pores somewhat shorter than thoseof the anterior paired petals, slit-shaped, acuminated inwards; pores in each pair opposite,
widely set. Each pore pair in the paired petals
conjugate, separated from the next by a row of
granules the number of which is three in the
middle part of the petals and two in the proximaland distal.
Peristome very eccentric in front (near theanterior sixth), very wide, about three times aswide as high, transverse. Plastron protamphister-429

nous. Periproct small, oval, vertically elongate,high up on the posterior truncated surface, partly
visible from above. Tubercles of various sizes,
perforate, crenulate, scrobiculate, somewhat
larger on the oral surface than on the aboral,
crowded on the plastron, widely scatteredelsewhere; tubercles on the aboral surface larger
on both sides of the frontal sinus and near theambitus in the anterior region; interporiferous
zones of all the ambulacra dotted with smaller
tubercles. A peripetalous fasciole distinct, wide,slightly curved towards the ambitus in theantero-Iateral interambulacra, bending shallowly
towards the apical system in the postero-Iateralinterambulacra, passing rather straight in theposterior interambulacrum; no other fascioles.
Measurements: - The specimens available aresecondarily deformed, and their original dimensions are hardly estimated. Nevertheless, theyroughly measure between 15 mm and 20 mm
in length. In the secondarily least depressed
specimen the test is a little less than two-thirds
as high as long.
Remarks: - The original specific diagnosis
given by Morishita (1962) and the later, moredetailed description by Nisiyama (1968) aremostly available, but some remarks on thespecific diagnosis are given in the lines to follow.
As mentioned before, this species has a heartshaped test which is as wide as long. Nisiyama(1968), on the other hand, maintained that thetest was roundly quadrate in outline, short andwider than long. Judging from my observationof the specimens available, his figured specimen(Nisiyama, 1966, pI. 18, figs. 2, 5, 9) is evidently
compressed longitudinally by the subsequentdistortion so as to show a test outline seemingly
shorter and broader than the normal form.
Morishita (1962) and Nisiyama (1968) described
the frontal sinus of the present species to berather vague or very shallow. However, this isconsidered to be due to the secondary deformation, since the frontal sinus is more or less deep
at least as far as the specimens examined areconcerned.
In one of the specimens, GSJ. F6196, eachporiferous zone of the frontal ambulacrum com-

430

Keisaku TANAKA

prises about 20 pore pairs within the fasciole,that of the anterior petals about 27 pore pairs
and that of the posterior petals about 21 porepairs. It should also be noted that the apicalsystem, not mentioned in detail by previous
authors, is ethmophract, the madreporite extending as far back as to separate the posterior genital
plates and touching the posterior occular plates.
Comparison: - This species closely resembles
Hemiaster (Hemiaster) frontacutus Stoliczka(1873, p. 13 (83), pI. 1 (11), figs. 7-8) from the
Utatur Group (Cenomanian - Turonian) of
southern India. But it differs from that species
in having a heart-shaped test and a very anteriorly displaced peristome. Moreover, there isa minor but distinct difference in course of
the peripetalous fasciole between the two. In
Hemiaster (Hemiaster) frontacutus the peripetalous fasciole passes rather straight in the anterolateral interambulacra and curves towards theambitus in the posterior interambulacrum.
H. (H.) uwajimensis is also closely similar toH. (H.) forbesi Baily (Baily, 1855, p. 463, pI. 12,
fig. 1; Woods, 1906, p. 280, pI. 33, figs. 8-9),
from the Senonian of southern Africa, especiallyin the general shape of the test, structure of
the apical system and course of the fasciole.
However, it is distinguished from that species
by its less distinct anterior notch and moreanterior position of the peristome. It also somewhat resembles Hemiaster (Hemiaster) similaris
Stoliczka (1873, p. 10 (80), pI. 1 (11), fig. 1)
from the Utatur Group, but differs from thatspecies in its smaller test and the frontal sinus
having constant depth throughout its length.
The present species is to some extent similar
to Hemiaster (Me caster) sp. aff. H. (M.) indicus
Stoliczka to be described below, but possesses
wider frontal ambulacrum, paired petals that are
more unequal in length and have longer, slitshaped pores, anterior petals being rather open
distally, and a peripetalous fasciole with lessregularly oval course.
Occurrence: - Uwajima area, western Shikoku; middle part of the Oguwa Formation,
Shimanto Supergroup, siltstone, Middle Turonianand Furushiroyama Formation, Uwajima Group,siltstone, Coniacian. A number of specimensof this species have been obtained from theTuronian and Coniacian at some other localitiesof the Uwajima area (Morishita, 1962; Nisiyama,1968). The type locality of this species (Morishita, 1962) is in the Yoshida area, north of
Uwajima, being contained in the upper part of
the Coniacian Yoshida Formation of Teraoka
et al. (1985) of the Shimanto Supergroup.
Hemiaster (Hemiaster) sp. A aff. H. (H.) stella(Morton)PI. 80, Figs. 4-6; Text·figs. 2, 3Compare:1854. Hemiaster stella, d'Orbigny, Paleont.
fran):., Terr. cret., Echin., ser. 1, vol. 6, p.
245, pI. 882, figs. 1-9.
1858. Hemiaster stella, Desor, Synopsis, p. 373.
1915. Hemiaster stella, Clark in Clark andTwitchell, Monogr. U. S. Geol. Surv., vol. 54,
p. 93, pI. 48, fig. 2.

Material: - Three specimens are available:
GSJ. F6065 (external mould of aboral surface),from loc. K-424, south of Tokuda (about 500 m
northeast of Kumasumi-ike), Kibi-cho, Aridagun, Wakayama Prefecture, Lower Shale Memberof Hirayama and Tanaka (1956a), Futakawa
Formation, Santonian (coil. Tanaka); GSJ.
F6097 A, B (A, internal mould; B, externalmould of aboral surface), from loc. U-15, uppercourse of the Chinomi-gawa, Urakawa-cho,
Urakawa-gun, Hokkaido, upper part of Unit Uoof Kanie (1966), Upper Yezo Group, Coniacian(colI. Tanaka); GSJ. F6099A, B (A, internalmould; B, incomplete external mould of aboral
surface), from loc. KS-72, upper course of the
Sekitambetsu-gawa, Sarufutsu-mura, Soya-gun,
Hokkaido, Unit Us of Tanaka (1960), Upper
Yezo Group, Upper Santonian (coil. Tanaka).
One comparable specimen, GSJ. F6195 (internalmould; coil. Tanaka), from loc. U-15 is alsoavailable.
Description: - The specimens examined areincomplete and secondarily deformed and their
original dimensions are hardly estimated. Nevertheless, they roughly measure between 17 mm

785. Upper Cretaceous Hemiasterids

,

lOmm

a

b

Text-fig. 2. Suggested figureofHemiaster (Hemiaster) sp. A aff. H. (H.)
stella (Morton). a, Aboral view. b, Leftlateral view. Restored from the material
available.

..

~a
iF)

c
Imm
'--_----'I

Text-fig. 3. Hemiaster (Hemiaster)
sp. A aff. H. (H.) stella (Morton). a, Fron·tal ambulacrum. b, Right anterior petal.
(GSJ, F6065). c, Apical system. (GSJ.
F6099).

and 23 mm in length. In the least secondarily
depressed specimen (GSJ. F6099), the test may
be about 0.7 as high as long.
The test is small, ovate in outline, widest
somewhat anterior to the midpoint and relatively
high. The frontal sinus is narrow and shallow,
becoming indistinct beyond the fasciole; theanterior notch, if any, is indistinct. The aboral
surface is inflated posteriorly, sloping anteriorly
from the highest point which is between theapical system and the posterior ambitus. The oral
surface is flattish on the whole and inflated in
the plastronal region. The apical· system is small,somewhat posterior and ethmophract, withfour gonopores; the posterior genital plates aremutually contiguous.
The frontal ambulacrum is narrow, very
shallowly sunken and subpetaloid, having pori fer-

431

ous zones which are much narrower than half
the width of the interporiferous zone. Each porepair is placed in an oblong depression, and thepores of each pair are round, oblique and close
together, being separated by a transverse granule.
The paired ambulacra are wide and shallowly
sunken, having rather small petals. The anterior
paired petals are shorter than the petaloid partof the frontal ambulacrum, longer and moredivergent than the posterior, broadly lanceolate,somewhat flexuous and closed distally. Theiranterior poriferous zones are somewhat narrower
than the posterior zones and nearly as wide as
the interporiferous zones. The pores are oval in
the anterior poriferous zones and longer andelongate oval to oblong in the posterior; thepores in each pair are opposite and widely set.
The posterior paired petals are shortest, as wide
as and about 0.6 as long as the anterior, oval,
more or less flexuous and closed distally. They
consist of poriferous zones of nearly equal
width which are nearly as wide as the interporiferous zones. The pores of each pair are similar,
elongate oval and opposite, being widely spaced.
Each pore pair in the paired petals is conjugate
and separated by a bourrelet adjoining the
conjugation groove between the pores.
The peristome is situated near the anterior
fourth. The plastron is mesamphisternous. The
tubercles on the aboral surface are of various
sizes, perforate, crenulate and widely scrobiculate, being widely spaced. Larger tubercles arerather close on both sides of the frontal sinus
and scattered near the ambitus in the anterior
region. The interporiferous zones of all theambulacra are dotted with smaller tubercles.
Numerous granules are present between the
tubercles. The peripetalous fasciole is welldeveloped and has rather oval course. No otherfascioles are present.
Remarks: - Since the specimens available
are poorly preserved, a periproct is not dis·scernible and tuberculation of the oral surface
is not known. Each poriferous zone of thefrontal ambulacrum consists of about 12 porepairs within the fasciole, that of the anterior
petals about 15 to 16 pore pairs and that of the432

Keisaku TANAKA

posterior petals about 13 pore pairs.
Comparison: - This species most closely
resembles Hemiaster (Hemiaster) stella (Morton)from the Senonian of France and the Upper
Cretaceous along the eastern coast of the UnitedStates in many respects, particularly in thegeneral outline of the test, features of the porepairs in all the ambulacra and course of theperipetalous fasciole. But it differs from thatspecies in its rather small, wide and somewhat
flexuous paired petals and less close tuberculation at least on the aboral surface.
The present species is easily distinguishable
from Hemiaster (Hemiaster) uwajimensis Morishita described above by its oval outline of thetest, shallower frontal sinus and by its featuresof the pore pairs in all the ambulacra. It is alsosimilar to Hemiaster (Hemiaster) sp. B aff. H.
(H.) punctatus d'Orbigny to be described below
in the general features of the test. In the latter
species, however, the frontal sinus does notextend distally beyond the fasciole and thepaired petals have oblong pore pairs, the closely
set and conjugate pores of each pair being notseparated by a bourrelet adjoining the conjugation groove between the pores.
The present form is somewhat similar to
Hemiaster tamulicus Kossmat (1897, p. 96, pi.
10, fig. 5) from the Trigonoarca Beds (Upper
Senonian) of southern India, but is separated
from that species by its lower test and wider
paired petals. However, the details of the featuresof pore pairs in all the ambulacra are not known
in the above Indian species. This makes impossible further comparison between the two species.
To sum up, the present form probably represents a new species of Hemiaster (Hemiaster)which is allied to but distinct from H. (H.) stella.
However, the available specimens are too poorly
preserved to propose a new specific name.
Occurrence: - Coniacian: lower part of theUpper Yezo Group, mudstone, Urakawa area,
Hidaka Province, Hokkaido. Santonian: lower
part of the Futakawa Formation, mudstone,
Yuasa area, Wakayama Prefecture; middle partof the Upper Yezo Group, calcareous concretionin mudstone, Kamisarufutsu area, Kitami Prov-

ince, Hokkaido.
Hemiaster (Hemiaster) sp. B aff. H. (H.)
punctatus d'Orbigny
PI. 80, Fig. 7; Text-fig. 4Compare:1854. Hemiaster punctatus d'Orbigny, Paleont.
franf., Terr. cret., Echin., ser. 1, vol. 6, p.
251, pI. 886, figs. 1-10.
1927. Hemiaster punctatus, Lambert, Mem. Mus.
Cienc. Nat. Barcelona, ser. Geol., vol. 1, p. 49.
1932. Hemiaster punctatus, Lambert, Mem. Soc.
Geol. France, nouv. serie, vol. 7, no. 16, p.
115.

Material: - YCM. 665, represented by an
external mould of the aboral surface, from
Shimukappu-chuo, Shimukappu-mura, Yufutsugun, Hokkaido, Unit U 1 of Kanie (1966), Upper
Yezo Group, Coniacian (coiL Kanie).
Description: - This specimen is incomplete
and secondarily deformed. It may reach thelength of at least 25 mm.
The test is small, subcircular in outline,
rounded anteriorly and slightly constricted
behind. The frontal sinus is narrow and shallow,
extending distally only to the fasciole; an anterior notch is absent. The apical system is small,somewhat posterior and ethmophract, withfour gonopores; the posterior genital plates aremutually contiguous.
The frontal ambulacrum is narrow, shallowly
sunken and subpetaloid. Each poriferous zone ismuch narrower than half the width of the interporiferous zone. Each pore pair is placed in
an oblong depression, and the pores in eachpair are round, oblique and close together, being
separated by a transverse granule.
The paired ambulacra are wide and very shallowly sunken, having rather small petals. The anterior paired petals are shorter than the petaloid
part of the frontal ambulacrum, longer and moredivergent than the posterior, broadly lanceolate,more or less flexuous and somewhat closed
distally. Their poriferous zones have oblongpores which are longer in the posterior poriferous
zones than in the somewhat narrower anterior.

785.

Upper Cretaceous Hemiasterids

.-

.~·.d
,

lmm

Text-fig. 4. Hemiaster (Hemiaster)sp. B aff. H. (H.) punctatus d'Orbigny,
YCM.665. a, Frontal ambulacrum. b,
Right anterior petal. c, Right posterior
petal. d, Apical system.
The posterior paired petals are shortest, slightly
narrower than and about 0.6 as long as the anterior, oval and closed distally. They consist of
poriferous zones of equal width which arebroader than the interporiferous zones, having
similar oblong pores. The pores of each pair in
the paired petals are opposite, close together andconjugate_
The tubercles on the aboral surface are ofvarious sizes, perforate, crenulate and widely
scrobiculate, being rather widely spaced. Larger
tubercles are rather crowded on both sides ofthe frontal sinus and scattered near the ambitus
in the anterior region. The interporiferous zonesof all the ambulacra are dotted with smaller
tubercles. The peripetalous fasciole is well developed and has rather oval course which istruncated in the antero-Iateral interambulacra
and nearly straight in the postero-Iateral interambulacra. No other fascioles are present.
Remarks: - Neither a peristome nor a periproct is preserved, and tuberculation of the oral
surface is not ascertained. Each poriferous zoneof the frontal ambulacrum, anterior petals andposterior petals comprises about 12, about 16
and more than 10 pore pairs within the fasciole,
respecti vely .
Comparison: - The present form is closely
similar to Hemiaster (Hemiaster) punctatusd'Orbigny from the Santonian to Campanianof western Europe and northern Africa in the433

general outline of the test, features of the frontal
sinus, width of the paired petals and features ofthe pore pairs in all the ambulacra. But theformer is distinguished from the latter by its
less sunken paired petals, shorter anterior petals,
longer and more closely set pores in each pair,less close tuberculation, and by its peripetalous
fasciole being truncated in the antero-Iateralinterambulacra and nearly straight in the posterolateral.
This species resembles Hemiaster (Hemiaster)
sp. A aff. H. (H.) stella (Morton) described abovein the general features of the test. But it differsfrom that species in that the frontal sinus extends distally only to the fasciole and in thatthe pores of each pair in the paired petals are
oblong and close together, being not separated
by a bourrelet adjoining the conjugation groove
between the pores.
This form also resembles Hemiaster integer
Lambert (19::1::1, p. 21, pI. 3, figs. 5, 6) from theUpper Turonian of Madagascar. Although theoriginal specific diagnosis of the latter was
given too briefly, our form has a peripetalous
fasciole that does not bend towards the apicalsystem but passes nearly straight in the posterolateral interambulacra.
To sum up, the present form probably represents a new species of Hemiaster (Hemiaster)which is allied to but distinct from H. (H.)
punctatus. However, the establishment of the
new species is suspended until more specimens
of better preservation are obtained.
Occurrence: .- Shimukappu area, Iburi Province, southern Hokkaido; Upper Yezo Group,
mudstone, Coniacian.
Hemiaster (Hemiaster) sp. C

PI. 80, Fig. 8, Text-fig. 5
Material: - GSJ_ F6187, represented by animperfect and fragmentary external mould of theaboral surface, from loc_ OF-6, about 500 m
southwest of Kashibaru, Oita City, Oita Prefecture, upper part of the Ryozen Formation,
Lowermost Subgroup of the Onogawa Group,
Upper Turonian (colI. Teraoka).

Keisaku TANAKA

434

Description: - This specimen is incomplete
and secondarily much defonned. The frontal
sinus is rather broad and shallow, widening
distally. It may become indistinct beyond thefasciole.
The frontal ambulacrum is rather wide,
shallowly sunken and subpetaloid. Its poriferous
zones are much narrower than half the width of
the interporiferous zone and composed of small
oval pores which are transverse in the outer row
and oblique in the inner row; the pores of eachpair are close together and separated by anoblong and transverse granule. The interporiferous area of each ambulacral plate is provided
with a row of granules the number of which ist",.::., three and four in the proximal, middle anddistal parts of the petaJoid area, respectively.
The paired ambulacra arc wide, slightly
broader than the fronta! ambulacrum, shallowly
sunken and petaloid, having poriferous zones
somewhat narrower than the interporiferous. The
anterior paired petals are somewhat longer,slightly wider and much more divergent than theposterior and rather open distally. The posterior
paired petals are rather short and about 0.6 aslong as and more or less narrower than theanterior and closed distally. The pores of eachpair in the paired petals are elongate oval, opposite, widely set and conjugate. The successive~~apore pairs of the anterior petals are separated bya row of granules the number of which is three
in the middle part of the poriferous zones andtwo in the proximal and distal parts. Those of
the posterior petals are separated by a row of
two granules throughout its length of the poriferous zones.
The tubercles are of various sizes, perforate,
crenulate and narrowly scrobiculate. On theaboral surface, they are somwhat close and larger
in the apical half of the antero-Iateral interambulacral areas, being the largest on both sides ofthe frontal sinus, but rather widely scatteredelsewhere. The interporiferous zones of all theambulacra are dotted with smaller tubercles.
The peripetalous fasciole is distinct and broad,being slightly curved towards the ambitus in theantero-Iateral interambulacra and embayed in thepostero-Iateral interambulacra.
Comparison: - This species resembles Hemiaster (Hemiaster) uwajimensis Morishita described above in some respects. But it differsfrom that species in the frontal sinus not extending distally beyond the fasciole and in thepresence of a row of several granules in theinterporiferous area of each ambulacral plate of
the frontal ambulacrum. I refrain from further
taxonomic discussion of the present fonn,because of the poor preservation of the material
available.
Occurrence: - Onogawa area, eastern Kyushu;
upper part (Inoceramus teshioensis Zone) of the
Ryozen Fonnation, Onogawa Group, mudstoneinterlaminated with sandstone, Upper Turonian.
Hemiaster (Hemiaster) sp. D
PI. 80, Fig. 9; Text-fig. 6

lmm
L--l

Text-fig. 5. Hemiaster (Hemiaster)sp. C, GSJ.F6287. a, Frontal ambulacrum.
b, Left anterior petal. c, Right posterior
petal.

Material: - GSJ. F6194, represented by an
external mould of the aboral surface, from loco
UF-7, northwest of Fukuura, Uwajima City,
Ehime Prefecture, Yorimatsu Fonnation of
Teraoka and Obata (1975), Uwajima Group,
Lower Santonian (colI. Teraoka).
Description: - This specimen is incomplete
and secondarily defonned. It may be about
20 mm or a little more in length.

785.

Upper Cretaceous Hemiasteridslmm'--_---.JI

Text-fig. 6. Hemiaster (Hemiaster)
sp. D, GSJ.F6194. a, Frontal ambulacrum.
b, Left anterior petal. c, Left posterior
petal.

The test seems to have an oval outline. The
frontal sinus is narrow and shallow, extending
distally only to the fasciole.
The frontal ambulacrum is shallowly sunken
and subpetaloid. Its pores are round and eachpore pair is placed in an oblong depression; thepores in each pair are oblique and close together,
being separated by a transverse granule.
The paired ambulacra are relatively wide andvery shallowly sunken, having rather short petals.
The anterior paired petals are much longer andmore divergent than the posterior, broadly
lanceolate, somewhat flexuous and more or lessclosed distally. Their anterior poriferous zones
are slightly narrower than the posterior zones
and nearly equal to the interporiferous zones
in width. The posterior paired petals are slightly
narrower than and about two-thirds as long as
the anterior, oval, slightly flexuous and closed
distally. They consist of poriferous zones ofnearly equal width which are similar in width
to the interporiferous zones. The pores of thepaired petals are similar and oval; the pores ofeach pair are opposite and widely set. Each porepair is bordered by a bourrelet which is notinterrupted between the pores and is seaparated
from the next by a row of two granules.
The tubercles are of various sizes, perforate,
crenulate and widely scrobiculate. They are
rather widely spaced on the aboral surface.

435

Larger tubercles are scattered near the ambitus, and much larger ones are rather close on
both sides of the frontal sinus. The interporiferous zones of the paired petals are dotted withsmaller tubercles. Numerous granules are densely
crowded between the tubercles. The peripetalous
fasciole is distinct, rather wide and of oval shapeon the whole.
Comparison: - The present form resembles
Hemiaster (Hemiaster) sp. A aff. H. (H.) stella(Morton) and Hemiaster (Hemiaster) sp. B. aff.
H. (H.) punctatus d'Orbigny described above, inmany respects. But it distinctly differs fromthose species in that the successive bourreletbordered pore pairs in each poriferous zone ofthe paired petals are separated by a row of two
granules. The specimen has about 12, 23 and 13
pore pairs within the fasciole in each poriferous
zone of the frontal ambulacrum, anterior petals
and posterior petals, respectively. Pore pairs in
the anterior petals is distinctly more numerous in
the present form than in the other two species
mentioned above. The material is, however, too
poorly preserved for further taxonomic discussion.
Occurrence: - Uwajima area, western Shikoku; Yorimatsu Formation, Uwajima Group,
mudstone interlaminated with sandstone, Lower
Santonian.
Subgenus Leymeriaster Lambert et Thiery, 1924
Hemiaster (Leymeriaster) polygonalis sp. nov.
PI. 81, Figs. 1, 2; Text-figs. 7, 8

Material: - Holotype, GSJ. F6063A, B (A,internal mould; B, external mould of aboral
surface), from a station about 700 m westsouthwest of Shichiminami, Seidan-cho, Miharagiln, Hyogo Prefecture, Shichi Shale Member of
Sasai (1936), Anaga Formation, Lower Subgroupof the Izumi Group, Campanian; paratype, GSJ.
F6072, represented by an internal mould, froma station about 500 m south of the peak of
Mt. Toyajo, Kanaya-cho, Arida-gun, Wakayama
Prefecture, Silty Fine-grained Sandstone Memberof Hirayama and Tanaka (1956b), Toyajo

Keisaku TANAKA

436

•

b

a

10mm

L--.J

c
Text-fig. 7. Suggested figure of
Hemiaster (Leymeriaster) polygonalis sp.
nov. a, Abroral view. b, Left lateral view.
c, Posterior view. Restored from theholotype and paratype.

lmm

L--.J

Text-fig. 8. Hemiaster (Leymeriaster)nov., GSJ. F6063. a,
Frontal ambulacrum. b, Left posterior
petal.
polygonalis sp.

Fonnation, Campanian (coli. Tanaka). Several
specimens (GSJ. F6163 etc.) which are comparable with this species are found in Division
C (Campanian) of Tanaka and Teraoka (1973)of the Himenoura Group in Shimokoshiki-jima,
the Koshiki Islands.
Diagnosis: - Test medium-sized, hexagonal in
outline, nearly as long as wide, widest near the
midpoint, contracted behind, with rounded
angles at the ambitus; frontal sinus wide, shallow,
somewhat open towards the ambitus with constant depth, fonning a broad and shallow notchin the anterior edge of the test, extending to
the peristome. Aboral surface inflated, highest
fairly behind the midpoint, gradually sloping

anteriorly, obliquely truncated posteriorly, witha distinct, convex-topped median carina between
the apical system and near the periproct, whichis the highest part of the test; posterior truncatedsurface slightly concave; posterior margin very
shallowly emarginate. Oral surface more or lessconvex on the whole, somewhat more inflated
in the plastronal region, shallowly depressedaround the peristome. Apical system somewhat
eccentric anteriorly.
Frontal ambulacrum widening from theproximal to the middle part and from the middle
to the distal passing with parallel sides, shallowly
sunken throughout its length, subpetaloid;
poriferous zones narrower than half the widthof the interporiferous zone; pores small, roundly
oval; outer pores transversely set; inner pores
obliquely set; pores in each pair close together,
separated by a small, oblong and transverse
granule.
Paired ambulacra somewhat flexuous, deeply
sunken, very unequal in length, petaloid. Anterior paired petals very much longer and much
more divergent than the posterior, slightly
curved backwards, moderately closed distally;each poriferous zone much broader than theinterporiferous zone, having oblong pore pairs;pores of each pair opposite, widely set. Posterior
paired petals about 0.4 to 0.5 as long as the anterior, moderately closed distally; each Pori ferous zone somewhat wider than the interporiferous zone; pores elongate oval; pores in each pair
opposite, widely set, conjugate.
Peristome near the anterior third, transverse.
Plastron protamphisternous. Periproct rather
small, oval, vertically elongate, at the upper endof the posterior truncated surface, visible fromabove. Tubercles on the aboral surface perforate,
crenulate, scrobiculate, of similar size, unifonnly
and rather closely spaced; interporiferous zonesof all the ambulacra dotted with smaller tuber·cles. A peripetalous fasciole distinct, broad,triangular in shape on the whole, narrowly
truncated posteriorly; no other fascioles.
Measurements: - Both the holotype and thepara type are secondarily defonned, and their
original dimensions are hardly estimated with

785.

Upper Cretaceous Hemiasterids

precision. The holotype in the deformed statemeasures 34 mm long, 32 mm wide and 15 mm
high. Its peripetalous fasciole is about 2 mm
wide.
Remarks: - In the holotype, the test is more
intensely deformed in its anterior part thanelsewhere and is somewhat lowered owing to
the secondary depression. The paratype islongitudinally much compressed so as to bemuch shorter than wide and much inflated. In
the two specimens the structure of the apicalsystem is not known because of the poor preservation. The paratype has about 27, more than
30 and about 21 pore pairs within the fasciolein each poriferous zone of the frontal ambulacrum, anterior petals and posterior petals,
respectively.
Comparison: - This new species closely resembles Hemiaster (Leymeriaster) sexangulatusd'Orbigny (d'Orbigny, 1854, p. 256, pI. 889,
figs. 1-9; Stoliczka, 1873, p. 18 (88), pI. 3 (13),fig. 6) from the Ariyalur Group (Campanian-Maastrichtian) of southern India, especially in the
shape of the test, length ratio of the anterior to
the posterior petals and course of the peripetalous
fasciole. But, it differs from that species in its
shallower frontal sinus, shallower anterior notch,
shorter and elongate oval pores of each pair in
the paired petals and broader fasciole.
The present species is distinctly separated
from the contemporary Hemiaster (Leymeriaster)
sp. aff. H. (L.) regulusanus d'Orbigny to be described below. The former has a hexagonal testwith a frontal sinus extending beyond thefasciole to the peristome, whereas the latter has
a rounded or oval test with a frontal sinus extending distally only to the fasciole. Moreover, inthe former the pores of each pair are conjugate;
such is not the case with the latter in which a
median longitudinal groove is placed at the
middle of the width of each ambulacral plate.
Occurrence: - Southwestern part of Awaji
Island, Shichi Shale Member, Anaga Formation,
Izumi Group, siltstone, Campanian; Yuasa area,
Wakayama Prefecture, Toyajo Formation, siltstone, Campanian. Comparable specimens arefound in the siltstone of Division C (Campanian)437

of the Himenoura Group in the Koshiki Islands.
Hemiaster (Leymeriaster) sp. aff.
H. (L.) regulusanus d'Orbigny

PI. 81, Fig. 3; Text-fig. 9Compare:1854. Hemiaster regulusanus d'Orbigny, Paleont.
fran(:., Terr. cret., Echin., ser. 1, vol. 6, p.
248, pI. 884, figs. 1-9.
1927. Hemiaster regulusi, Lambert, Mem. Mus.
Cienc. Nat. Barcelona, ser. Geol., vol. 1, p.
49.

1936. Hemiaster regulusi, Lambert, Bull. Soc.
Hist. Natur. Toulouse, vol. 69, p. 83.
Material: - GSJ. F6172A, B (A, internalmould; B, external mould of aboral surface),from Ebisukui, Onohara-cho, Mitoyo-gun, Kagawa Prefecture, Ebisukui Mudstone Memberof C. Nakagawa (1961), Lower Subgroup of the
Izumi Group, Campanian. This specimen wascollected by T. Nakagawa and donated to the
Geological Survey of Japan through the late
Dr. M. Nakano.
Description: - This is poorly preserved andsecondarily deformed. It roughly measures alittle more than 20 mm in length.
The test seems to have a rounded or oval
outline not emarginated in front. The frontal

lmm~

Text·fig. 9. Hemiaster (Leymeriaster)
sp. aff. H. (L.) regulusanus d'Orbigny,
GSJ. F6172. a, Frontal ambulacrum. b,
Left anterior petal. c, Left posterior
petal.

438

Keisaku TANAKA

sinus is very shallow, extending distally only tothe fasciole. An anterior notch is absent.
The frontal ambulacrum is narrow, very
shallowly sunken and subpetaloid. It has roundpore pairs; the pores in each pair are obliquely
set and close together, being separated by anoblong and transverse granule.
The paired ambulacra are wide and very
shallowly sunken. The anterior paired petals aremuch longer than the posterior, lanceolate,slightly flexuous and moderately closed distally.
Their pores are elongate oval in the anterior
poriferous zones and are slightly longer andoblong in the somewhat wider posterior poriferous zones which are nearly equal to the interporiferous zones in width; the pores in each pairare opposite, widely set and nonconjugate. The
posterior paired petals are much shorter than,a little under half as long as and nearly as wide as
the anterior ones, oval, nearly straight anddistinctly closed distally. They consist of pori ferous zones of nearly equal width, having similarelongate oval pore pairs_ The pores of each pairin the posterior petals are opposite, widely set
and nonconjugate. In the paired petals a medianlongitudinal groove is placed at the middle of thewidth of each ambulacral plate.
The peripetalous fasciole is distinct.
Remarks: - Because of unfavourable preservation, the structure of the apical system is notknown and neither a peristome nor a periproct
is discernible.
Comparison: - This species closely resembles
Hemiaster (Leymeriaster) regulusanus d'Orbigny
from the Santonian of France and Spain, in thegeneral outline of the test, the anterior petals
being very much longer than the posterior (theformer being about twice as long as the latter),and in the features of the ambulacral plates ofthe paired petals (a median longitudinal groove
being placed at the middle of the width of eachplate). However, there are some minor but
distinct differences between them. In H. (L.)
regulusanus the pores of the paired petals are
acuminated inwards. Such is not the case withthe present form. In our specimen the approximate number of pore pairs is 11, 23 and 15

within the fasciole in each poriferous zone of
the frontal ambulacrum, anterior petals andposterior petals, respectively. The anterior petalsof the present species have a much smaller
number of pore pairs than do those of Hemiaster(Leymeriaster) regulusanus with a much larger
test. As to the frontal ambulacrum and posterior
petals, on the other hand, their respective number of pore pairs are similar in the two species.
The present form is clearly distinguished fromthe contemporary Hemiaster (Leymeriaster)
polygonalis sp. nov. described above by its
rounded or oval outline of the test, frontal sinus
not extending distally beyond the fasciole andthe non conjugate pore pairs in the paired petals.
To sum up, a possibility cannot be denied
that the present form represents a new subspeciesof Hemiaster (Leymeriaster) regulusanus which isallied to but distinct from the typical form from
France. However, I provisionally call it Hemiaster(Leymeriaster) sp. aff. H. (L.) regulusanus d'Orbigny, without proposing a new subspecific name,until more and better specimens are obtained.
Occurrence: - Western part of the Asan
Mountain Range, eastern Shikoku; Ebisukui
Mudstone Member, Izumi Group, mudstone,
Campanian.
Subgenus Mecaster Pomel, 1883
Hemiaster (Mecaster) sp. aff. H. (M.) indicus
Stoliczka
PI. 80, Fig.10;PI. 81, Figs. 4, 5; Text-fig. 10

Compare:1873. Hemiaster indicus Stoliczka, Mem. Geol.
Surv. India, Palaeont. Indica, ser. 8, vol. 4,
pt. 3, p. 16 (86), pI. 2 (12), figs. 6, 7, pI. 3(13), fig. 1.

Material: - Three specimens are available:
GSJ. F6183A, B (A, internal mould of aboral
surface; B, external mould of aboral surface),from loco OF-54, about 800 m northwest of
Nakahata, Shitsuru, Oita City, Oita Prefecture,
Ugaku Formation of Teraoka (1970), Middle
Subgroup of the Onogawa Group, Lower Santonian (coli. Teraoka); GSJ. F6186, imperfect785.

Upper Cretaceous Hemiasterids

external mould of the aboral surface, from loc.
OF-71, about 500 m southwest of Taishogun,
Suehiro, Usuki City, Oita Prefecture, Mizugajo
Formation of Teraoka (1970), Upper Subgroupof the On ogawa Group, Lower Santonian (colI.
Teraoka); GSJ. F6188, internal mould, fromloco OF-64, about 500 m east of Hisaeuchi,
Usuki City, Takeyama Formation, Middle Subgroup of the Onogawa Group, Lower Santonian(colI. Teraoka).
Description: - The specimens are poorly
preserved and secondarily depressed. The test
seems rather ovate in outline. The frontal sinus isnarrow and shallow, widening towards theambitus. The aboral surface is somewhat strongly
inflated near the apical system in the anterolateral interambulacral areas and has a moreor less distinct median carina in the posterior
interambulacral area. The apical system is small,slightly posterior and ethmophract, having four
gonopores. The madreporite extends as far backas to separate the posterior genital plates andthen to touch the posterior occular plates.
The frontal ambulacrum is narrow, widening
from the proximal to the middle part and f!om
the middle to the distal passing with parallelsides. It is shallowly sunken and subpetaloid.
Each poriferous zone is narrower than half thewidth of the interporiferous zone and has small
oval pores within the fasciole. The pores of eachpair are transverse in the outer row, oblique~~b

Text-gig. 10. Hemiaster (Mecaster)
sp. aff. H. (M.) indicus Stoliczka, GSJ.
F6183. a, Frontal ambulacrum. b, Left
anterior petal. c, Left posterior petal.
d, Apical system.

439

in the inner row and close together, and areseparated by an oblong and transverse granule.
The paired ambulacra are rather broad, rather
moderately flexuous, shallowly sunken andpetaloid. The anterior paired petals are nearly
as long as and much wider than the petaloid
part of the frontal ambulacrum. They are longer,
somewhat wider and much more divergent thanthe posterior paired petals, being rather open
distally. In the anterior petals, the anterior
poriferous zones are more or less narrower thanthe posterior poriferous zones which are nearly
equal to the interporiferous zones in width. The
pores are oval in the inner row of each poriferous
zone and oblong and acuminated inwards in theouter row. The posterior paired petals are rather
long, about four-fifths as long as and somewhat
narrower than the anterior petals and more orless closed distally. Their poriferous zones areof nearly equal width and nearly as wide as theinterporiferous zones. Each poriferous zone isprovided with oval inner pores and elongate
oval outer ones acuminated inwards. The poresof each pair in the paired petals are opposite andwidely set. In these petals, each pore pair isbordered by a bourrelet which is not interrupted
between the pores, being separated from the next
by a granule.
The peristome is near the anterior fifth. The
periproct is small, oval in outline and verticallyelongate. The tubercles are of various sizes,
perforate, crenulate and scrobiculate. They arewidely scattered on the aboral surface with thelargest of them on both sides of the proximal
half of the frontal sinus. The interporiferous
zones of all the ambulacra are dotted withsmaller tubercles. The peripetalous fasciole iswell developed and has oval course.
Remarks: - One of the specimens, GSJ.
F6183, though poorly preserved and secondarily
deformed, roughly measures 29 mm in length.
In this specimen, each poriferous zone of thefrontal ambulacrum, anterior petals and posterior
petals comprises about 17, about 27 and about
23 pore pairs within the fasciole, respectively.
Comparison: - The present form most closely
resembles Hemiaster (Mecaster) indicus Stoliczka,

440

Keisaku TANAKA

from the Ariyalur Group (Campanian - Maastrichtian) of southern India, among many otherhitherto described foreign species of the subgenus in the general features of the test. But it isdistinguished from that species by the narrower
frontal sinus, the paired petals that are less closed
distally and have bourrelet-bordered pore pairs,
and by the more regularly oval course of theperipetalous fasciole.
The present species is somewhat similar to
Hemiaster (Hemiaster) uwajimensis Morishita
described above, but differ from that species inthat the frontal ambulacrum is narrower, thepaired petals are subequal in length, the anterior
petals are rather open distally, the pores of thepaired petals are shorter and nonconjugate, andin that the peripetalous fasciole has more regularly oval course.
To sum up, the present form probably represents a new species of Hemiaster (Me cas te r)which is allied to but distinct from H. (M.)
indicus. However, I postpone proposing a new
specific name until more and better specimens
are obtained.

Occurrence: - Onogawa area, eastern Kyushu;
Ugaku Formation (sandy siltstone) and Takeyama
Formation (sandy mudstone), Middle Subgroupof the Onogawa Group, Lower Santonian, andMizugajo Formation, Upper Subgroup of the
Onogawa Group, mudstone, Lower Santonian.

Concluding Remarks
Summarizing the systematic descriptions, thefollowing eight species belonging to the genus
Hemiaster are identified on the material fromthe Upper Cretaceous of Japan, with indicationof their stratigraphic occurrence in parentheses:
Hemiaster (Hemiaster) uwajimensis Morishita(Turonian - Coniacian)Hemiaster (Hemiaster) sp. A aff. H. (H.) stella(Morton) (Conician - Santonian)
Hemiaster (Hemiaster) sp. B aff. H. (H.)
punctatus d'Orbigny (Coniacian)Hemiaster (Hemiaster) sp. C (Turonian)
Hemiaster (Hemiaster) sp. D (Santonian)
Hemiaster (Leymeriaster) polygonalis sp. nov.

Explanation of Plate 80
Figs. 1-8. Hemiaster (Hemiaster) uwajimensis Morishita. . . . . . . . . . . . . . . . . . . . . Page 428
1. GSJ. F6196 from loco UF-65, Uwajima area, aboral view, x 2.
2. GSJ. F6198 from loco UFoS, Uwajima area, aboral (a) and oral (b) views, x 2.
3. GSJ. F6199 from loco UFoS, Uwajima area, aboral (a), oral (b) and right lateral (c) views,
x 2.
Figs. 4-6. Hemiaster (Hemiaster) sp. A aff. H. (H.) stella (Morton) . . . . . . . . . . . . . . Page 430
4. GSJ. F6065 from loco K-424, Yuasa area, aboral view of an external mould, x 2.
5. GSJ. F6097 from loco U-15, Urakawa area, aboral view, x 1.5.
6. GSJ. F6099 from loco KS-72, Kamisarufutsu area, aboral view, x 2.5.
Fig. 7. Hemiaster (Hemiaster) sp. B aff. H. (H.) punctatus d 'Orbigny . . . . . . . . . . . . Page 432
YCM.665 from the Shimukappu area, aboral views of an external mound (a) and of a gum casttaken from the same external mould (b), x 2.
Fig. 8. Hemiaster (Hemiaster) sp. C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Page 433
GSJ. F6187 from loco OF-6, Onogawa area, aboral view of a gum cast taken from the externalmould of a fragmentary test, x 1.3.
Fig. 9. Hemiaster (Hemiaster) sp. D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Page 434
GSJ. F6194 from loco UF-7, Uwajima area, aboral view of the external mould of a fragmentary test, x 2.
Fig. 10. Hemiaster (Mecaster) sp. aff. H. (M.) indicus Stoliczka . . . . . . . . . . . . . . . . Page 438
GSJ. F6186 from loco OF-71, Onogawa area, aboral view of a gum cast taken from the external mould of a fragmentary test, x 2.
All speciments illustrated here are internal moulds, unless otherwise stated.

TANAKA : Upper Cretaceous Hemiasterids

Plate 80

70

7b

5

8

785.

Upper Cretaceous Hemiasterids(Campanian)
Hemiaster (Leymeriaster) sp. aff. H. (L.)
regulusanus d'Orbigny (Campanian)
Hemiaster (Mecaster) sp. aff. H. (M.) indicus
Stoliczka (Santonian)
Hemiasterid echinoids are the dominant constituents in the Upper Cretaceous echinoid faunaof Japan. Actually, in addition to the species
listed above, there are many other Hemiasterspecimens from various areas of Japan, which are
specifically undeterminable because of the poor
preservation.
The species belonging to the subgenus Hemiaster described here fall into three groups, a, (3and 'Y. The a group has a heart-shaped test, awide and relatively deep frontal sinus extending
to the ambitus, a rather distinct anterior notch,a wide and moderately deeply sunken frontal
ambulacrum and broad and deeply sunken paired
petals. This group is referred to the typical formof the subgenus Hemiaster, being represented by
Hemiaster (Hemiaster) uwajimensis Morishita.
In the (3 group, the test is oval in outline, thefrontal sinus is rather wide and shallow, extending at least to the fasciole and the frontal ambulacrum and paired petals are wide and shallowly
sunken. Hemiaster (Hemiaster) sp. C is includedin this group.
The 'Y group is characterized by the oval to
subcircular test, the narrow and shallow frontal
sinus extending only to the fasciole, the anterior
notch being absent or indistinct, the narrow andshallowly sunken frontal ambulacrum and by
the rather small paired petals which are broadand shallowly sunken. This group comprises
Hemiaster (Hemiaster) sp. A aff. H. (H.) stella(Morton), Hemiaster (Hemiaster) sp. B aff. H.
(H.) punctatus d'Orbigny and Hemiaster (Hemiaster) sp. D.
The above features of the 'Y group somewhat
recall Integraster (Lambert and Thiery, 1924;
section) that is now synonymous with the subgenus Hemiaster according tb Lambert (1931 -32) and Fischer (in Moore, ed., 1966). On theother hand, the general outline of the test andfaint frontal sinus, together with the rather small
paired petals, show some resemblance of the'Y group to the subgenus Bolbaster. However,441

the test of at least Hemiaster (Hemiaster) sp. A
aff. H. (H.) stella is not so high and subglobular
as the test of Bolbaster species. In short. the (3group is of intermediate form between the agroup and the 'Y group, being more closely allied
to the latter. As to the 'Y group, it shOUld also
be noticed that in the frontal ambulacrum eachpore pair is placed in a depression and the tubercles are widely scrobiculate. These features,
however, are not seen in the a and (3 groups. The
above-mentioned feature of the pore pairs in thefrontal ambulacrum is one of the prominent
features of Hemiaster (Hemiaster) stella and H.
(H.) punctatus to which Hemiaster (Hemiaster)
spp. A and B are similar respectively. The two
foreign species were allocated to Integraster.
Because of the insufficiency of the material, I
refrain from further discussion of these taxonomic problems.
Hemiaster (Hemiaster) uwajimensis of the agroup is closely allied to certain species fromthe Utatur Group (Cenomanian - Turonian)of southern India and also to a certain species
from the Senonian of Pondoland, southern
Africa, which, in tum, is to some extent similar
to one of the above Indian species. Hemiaster(Hemiaster) spp. A and B of the 'Y group present
close resemblance to certain Senonian species
from western Europe respectively, one of which
occurs also in the Upper Cretaceous along theeastern coast of the United States. Moreover,hemiasterids resembling those of the 'Y groupoccur in the Upper Cretaceous of southern India
and Madagascar as well as in that of western
Europe. Hemiaster (Leymeriaster) polygonalis
sp. nov. and the Hemiaster (Mecaster) species
are closely allied to certain upper Senonian
species of southern India, respectively. On theother hand, another Hemiaster (Leymeriaster)
species somewhat resembles a certain species
from the Senonian (Santonian) of western
Europe. In addition, Hemiaster (Mecaster)
mikasaensis Tanaka (1984, p. 196, pI. 3, figs.
1-3) from the Lower Cenomanian of Hokkaido
closely resembles a certain Hemiaster (Mecaster)
species from the Cenomanian (probably Lower
Cenomanian) of western India. Thus, it may bewell said that the Upper Cretaceous hemiasterid

442

Keisaku TANAKA

assemblage of Japan has some affinity withthat of the Indo-malagasy province (including
southern Africa) on the one hand and with thatof the west European province in lesser degree
on the other_
Finally, a brief remark is given on the modeof occurrence and mode of life of the described
Hemiaster species. According to Mortensen(1950), Recent species of Hemiaster inhabit
depths of about 140 to about 4,000 m. Thus,
the Hemiaster species described here which occur
in argillaceous rocks were generally mud-dwellers
living in "deep sea." They were burrowers.
Scattered specimens of Hemiaster (Hemiaster)uwajimensis of the a group are found in fossiliferous siltstone (probably of shelf facies)
at many localities of the Uwajima area. The rockfrom which Hemiaster (Hemiaster) sp. A aff.
H. (H.) stella and Hemiaster (Hemiaster) sp. B
aff. H. (H.) punctatus of the r group came,is mudstone which is regarded as having been
deposited in an offshore, deep environment.
Hemiaster (Hemiaster) sp. D of the same group
was obtained from relatively fine-grained mudstone interlaminated with sandstone of shaly
flysch facies in the Uwajima area. Hence, it isvery likely that Hemiaster (Hemiaster) uwajimensis generally preferred a silt substratum and the
Hemiaster (lJemiaster) species of the r grouppreferred either a mud substratum or that onto
which sand material was frequently supplied
forming laminae, though allochthonous insome cases. Moreover, it seems probable that
Hemiaster (Hemiaster) uwajimensis lived inshallower waters than Hemiaster (Hemiaster)
species of the r group. And, by the way, the rockcontaining Hemiaster (Hemiaster) sp. C of the~ group is relatively coarse-grained mudstoneinterlaminated with sandstone.
Hemiaster (Hemiaster) uwajimensis has alonger, wider, deeper frontal sinus, a deeper
anterior notch, more pore pairs in the frontal
ambulacrum and larger, more deeply sunken
paired petals with more numerous and moreelongated pore pairs than do the Hemiaster(Hemiaster) species of the ~ and r groups.
Moreover, this species has a more anteriorly
positioned peristome than Hemiaster (Hemiaster)
sp. A aff. H. (H.) stella. In view of information
regarding the functional significance of morphological features of certain spatangoid echinoids(e.g. Nichols, 1959; McNamara and Philip,1980), these differences suggest that Hemiaster(Hemiaster) uwajimensis burrowed into muddy
bottom sediments more deeply than did theother species of Hemiaster (Hemiaster).
References Cited
Baily, W. H. (1855): Description of some Cretaceous fossils from South Africa. Quart. Jour.
Geol. Soc. London, vol. 11, p. 454-465,
pis. 11-13.
Clark, W. B. and Twitchell, M. M. (1915): The

Explanation of Plate 81
Figs. 1, 2. Hemiaster (Leymeriaster) polygonalis sp. nov . . . . . . . . . . . . . . . . . . . . . Page 435
1. GSJ. F6063, holotype, from Awaji Island, aboral (a), oral (b), left lateral (c), anterior (d)and posterior (e) views of an internal mould (A), x 1.2, and aboral view of an externalmould (B) (f), x 1.5.
2. GSJ. F6072, paratype, from the Yuasa area, aboral (a), oral (b), left lateral (c), anterior(d) and posterior (e) views, x 1.2.
Fig. 3. Hemiaster (Leymeriaster) sp. aff. H. (L.) regulusanus d'Orbigny . . . . . . . . . . Page 437
GSJ. F6172 from the Asan Mountain Range, aboral view, x 2.
Fig. 4, 5. Hemiaster (Mecaster) sp. aff. H. (M.) indicus Stoliczka . . . . . . . . . . . . . .. Page 438
4. GSJ. F6183 from loco OF-54, Onogawa area. 4a, Aboral view of an internal mould (A),x 1.5. 4b, Aboral view of an external mould (B), x 1.5.
5. GSJ. F6188 from loco OF-64, Onogawa area, aboral (a) and oral (b) views, x 2.
All specimens illustrated here are internal moulds, unless otherwise stated.

TANAKA: Upper Cretaceous Hemiasterids.. ,~;p .~ 4. I i'
.ttl. /~/ .~ ~
, ,.,' . ,.
~

2d40

Plate 81

785.

Upper Cretaceous Hemiasterids

Mesozoic and Cenozoic Echinodermata of
the United States. Monogr. U. S. Geol. Surv.,
vol. 54, p. 1-341, pIs. 1-108.
Desor, E. (1855-58): Synopsis des Echinides
fossiles. 490 p., 44 pIs. Geneva; Ch. Rein·wald, Paris; Kriedel and Niedner, Wiesbaden.
Hirayama, K. and Tanaka, K. (1956a): The geological sheet map "Kainan," scale 1 :50,000,
and its explanatory text. Geol. Surv. Japan,
62 p. (in Japanese with English abstract,
12 p.).
and - - (1956b): The geological sheet
map "Todorogi," scale 1 :50,000, and its
explanatory text. Geol. Surv. Japan, 37 p.
(in Japanese with English abstract, 11 p.).
Jimbo, K. (1894): Beitrage zur Kenntnis derFauna der Kreideformation von Hokkaido.
Palaeont. Abhandl., N. F., vol. 6, p. 147194, pIs. 17-25.
Kanie, Y. (1966): The Cretaceous deposits in
the Urakawa district, Hokkaido. Jour. Geol.
Soc. Japan, vol. 72, p. 315-328 (in Japanesewith English abstract).
Kossmat, F. (1897): The Cretaceous deposits ofPondicherri. Rec. Geol. Surv. India, vol. 30,
p. 51-110, pIs. 6-10.
Lambert, J. (1927): Revision des Echinides
fossiles de la Catalogne. Mem. Mus. Ciencias
Nat. Barcelona, ser. Geol., vol. 1, no. 1,
p. 1-102, pIs. 1-4.
--(1931-32): Etudes sur Echinides fossiles
du Nord de I 'Afrique. Mem. Soc. Geol.
France, nouv. serie, vol. 7, no. 16, p. 1-228,
pIs. 1-8.
--(1933): Echinides de Madagascar communi·ques par M. H. Besairie. Ann. Geol. Servo
Mines Mad., pt. 3, p. 1-49, pIs. 1-4.
- - (1936): Observations critiques sur quelques
Hemiaster du Sud-Ouest de la France. Bull.
Soc. Hist. Natur. Toulouse, vol. 69, p. 7794, pI. 6.
- - and Thiery, P. (1924): Essai de nomenclature
raisonnee des Echinides. pts. 6, 7, p. 385512, pIs. 10, 11, 14. Libraire Ferriere,
Chaumont.
McNamara, K. J. and Philip, M. (1980): Aus·
tralian Tertiary schizasterid echinoids. AIcheringa, vol. 4, p. 47-65.
Moore, R. C., ed. (1966): Treatise on Invertebrate
Paleontology. Part U, Echinodermata 3, vol.
2, 695 p. Geol. Soc. America, Inc. and Univ.

443

Kansas Press.
Morishita, A. (1955): Cretaceous echinoid,
Niponaster from the Island of Awaji, Japan.
Trans. Proc. Palaeont. Soc. Japan, N. S., no.
20, p. 99, 100, pI. 15.
- - (1962): Cretaceous echinoid, Hemiasterfrom Shikoku, Japan. (On some fossil echinoids of Japan, II). Jour. Earth Sci., Nagoya
Univ., vol. 10, p. 113-116, pI. l.
Mortensen, Th. (1950): A Monograph of theEchinoidea. Vol. 5, pt. 1, Spatangoida I,
432 p., 25 pIs. C. A. Reitel, Copenhagen.
Nakagawa, C. (1961): The Upper Cretaceous
Izumi Group in Shikoku. Jour. Gakugei,
Tokushima Univ., Nat. Sci., vol. 11, p. 77124.
Nichols, D. (1959): Changes in the Chalk hearturchin Micraster interpreted in relation toliving forms. Phi/os. Trans. Roy. Soc. London, ser. B, vol. 242, p. 347-437, 1 pI.
Nisiyama, S. (1966): The echinoid fauna fromJapan and adjacent regions. Part I, Palaeont.
Soc: Japan, Special Papers, no. 11, p. 1227, pIs. 1-18.
- - (1968): The echinoid fauna from Japan andadjacent regions. Part II, Ibid., no. 13, p. 1491, pIs. 19-30.
Orbigny, A. d'. (1853-60): Paleontologie
franfaise: Description des animaux invertebres. Terrain cretace, Echinides. ser. 1,
vol. 6, p. 1-598, pIs. 801-1006 (Completedby G. H. Cotteau).
Saito, T. (1959): Notes on some Cretaceous fossils from the Nakaminato Formation,
Nakaminato City, Ibaraki Prefecture, Japan.
Part II. Bull. Fac. Lib. Arts, Ibaraki Univ.,Nat. Sci., no. 9, p. 79-85, pIs. 1, 2.
Sasai, H. (1936): Izumi Sandstone series in
Awaji. Jour. Geol. Soc. Japan, vol. 43, p.
590-602, pIs. 28, 29 (in Japanese).
Stoliczka, F. (1873): Cretaceous fauna of thesouthern India. The Echinodermata. Mem.
Geol. Surv. India, Palaeont. Indica, ser. 8,
vol. 4, pt. 3, p. 1 (71)-57 (127), pIs. 1(11)-7 (17).
Tanaka, K. (1960): The geological sheet map"Kamisarufutsu," scale 1 :50,000, and its
explanatory text. Geol. Surv. Japan, 65 p.
(in Japanese with English abstract, 8 p.).
- - (1984): Some Cretaceous echinoids fromJapan. Bull. Geol. Surv. Japan, vol. 35, p.

Keisaku TANAKA

444

189-202, pis. 1-3.
- - and Teraoka, Y. (1973): Stratigraphy andsedimentation of. the Upper Cretaceous
Himenoura Group in Koshiki-jima, southwest Kyushu, Japan. Bull. Geol. Suru. Japan,
vol. 24, p. 157-184, pis. 15-24 (in Japanesewith English abstract).
Teracka, Y. (1970): Cretaceous fonnations in
the Onogawa Basin and its vicinity, Kyushu,
Southwest Japan. Rept. Geol. Suru. Japan,
no. 237, p. 1-87, pis. 1-18 (in Japanesewith English abstract, 3 p.).
- - , Kashima, N. and Ikeda, Y. (1985): Geologyof the Uwajima District. Quadrangle Series,

Scale 1 :50,000, Geol. Surv. Japan, (inJapanese with Egnlish abstract (in press).
and Obata, I. (1975): Stratigraphy of theUpper Cretaceous Uwajima Group. Mem.
Natn. Sci. Mus., no. 8, p. 5-20, pis. 1, 2
(in Japanese with English abstract).
- - , - - and Mizuno, I. (1980): Stratigraphyof the Shimanto Supergroup in the Chikanaga
area, west Shikoku, with special reference tothe Miyakoan and Gyliakian Series. Bull.
Geol. Suru. Japan, vol. 31, p. 307-319,
pis. 1, 2 (in Japanese with English abstract).
Woods, H. (1906): The Cretaceous fauna of
Pondoland. Ann. South African Mus., vol. 4,
pt. 7, p. 275-350, pis. 33-44.

Anaga 1JiiT)}jl f.t Arida 11m. Asan 1JiiTt.i. Awaji i:R~~. Chinomi-gawa fL 'ffJII. Ebisukui IIiJ~ii"i.
Fukuura fiiMl1. Furushiroyama l!:i-.!p}:UI. Futakawa =-111. Hidaka B i~. Himenoura b£!i!fi. Hiromi$Ji!.. Hisaeuchi Wi1'l. Iburi N!!W<. Izumi 'fIlJit. Kamisarufutsu J:ifttL.. Kanaya ~I¥:. Kashibaru
W~. Kibi ii'VIll. Kitami ~tJi!.. Kitauwa ~ti'~;fll. Koshiki fill. Kumasumi·ike tlHti1!I. Mihara =::Jjj(. Mitoyo =::~. Mizugajo 71\ 'r 1$;. Nakahata rj':l:il1. Oguwa 'J':8'. Onogawa ::k'RfJII. Onohara'RfJjj(. Ryozen ';:';:UI. Sakashitazu Jt)(Tif.. Sakura-toge ,wl~t. Sarufutsu ~t&. Seidan fIllik Sekitambetsu-gawa ::j'C) /;/U)IJjil. Shichi ;GtU. Shichiminami ;G9;rlWi. Shimokoshiki-jima Tfill~. Shimukappu ,5 lEE. Shitsuru Tflt'[¥!. Soya ~ft. Suehiro
Taishogun :1dWifL. Takeyama JiotJlI.
Tanikira 1'tH*. Tokuda 1m(EIl. Toyajo nw~. Ugaku tJIfi-. Urakawa liliiilJ. Usuki flfr-. Uwajima "jq1J.I~j, Yezo tfd%. Yorirnatsu 'r,H'L Yoshida ri'lTI. Yuasa i~il1:. Yufutsu 9J.tL

*-

*$.

R *iIft: (=J ilHc~l!Jl Herniaster ~O) ry =- fl:;1:1: *M%:l1!!.O) J:i1ill'liIfi*tJ, i?ilE Lt.: Hemiaster !~O) ry =- ft.:fi 1'::'-') l ,-C. Hernias!er (5 fil)). Leyrneriaster (2 ND &.If Maaster (l;firo 0) 3 'IHil8 ;f.fi~,i{~~1j L.i\Ij:_¥!J,*(J'~~c;jiJ(~ff..,t.:o Herniaster ifE!~O) 1 ;f.l!~t*fI)O)I1Hn;p1i-C-;j; I). Leyrneriaster '1[i!~O) 1 N!lt~TNr-C·. tJ /,'=-7 :/tJ'i?.il¥.-t7.>. Herniaster ijji!~O)
1\lHtJf;Jl&J: 3 r.¥1,::,;'J-ft i?;/1. 7.> n:I!WO) Herniaster !liJAfollHt --( :/ f ~" fl tJ' 7-. tJ Iv U¥-i 7 7 ~tJ~;'l;-1:.r) 1)(O)~:;r;cJti'H~t);;j;I). -fflIVY3-P -Y'~O)~~I.::.ftJt,:bO)bft-/v-C·l'7.>, t.et;.
0Herniaster'IEk~O)t-,fttO)ilE:jkI'::' b ;'4''& L.

- iaIO)fif!I;::'-::>l '-C 1:ii!j-f>R).-\~J1tJE U': o

11I.piJ'fm

ill!

1m

B

:it!l

----_._-- ----------

00 liMit • JIUjt:k~

1984~10}j 31 B

1985~ 2 }j 2, 3 B

Mfliii$.i2, : 113 :7tJl~Jj\mJtJjnK~1:: 2-4-16
B*~~.~~~~-

B*~1::~~~

rr~~

01985~ 2}j 1 B r::..ooliH~it~M-c:· B*~1::4~J'¥=f'<fiILV:50Ji'iJ~~c~A~~rr 5 T~ ..('-t 0 ~~1Hv:v:'lt,'11j~f,llJ~l*Jf'X L ;J: -to

~

n

~

iE

4:;\,1:; No. 134 f:.1'kO),~~!l((tJ~a; I) i U-:O)-C,lJiI: Li-to

ErrataMajima (1984): Observations on occurrences of Japanese Neogene naticids(Gastropoda) bearing calcareous opercula. Trails. Proc. Palaeont. Soc. Japan,
N. S., No. 134, p. 361-373, pis. 68-70.
-.. -• . -__~ _ _.. -.-~-----o-~------O=---.---O---:-::-::::--=--

Read

Page

Line

363
368
368

right 3left 24
right 28

- - - - - : - :•.
---_--~-.-=__=___-__,__.

-

For

is characterized by hm ofig

(Broderip and Sowerby,

PI. 69

PI. 68

(A) :

(a) :

l3*ti~!fbJ$~
1984~1O}jl0S

t:rJ

1984 ~1O}j 15 S

ge

ISSN

X J~\ ~ ~1' 1: 2-4-16
rl ''f~ ft 10% -1: ~ :'I - P:l(:11& 1& rJ I!E~ 84 780 It)*(~

0031-0204

S *~1:.~~~¥IH5··*'C.

*i ~ ~*

0 3 - 8 1 5 - 1 9 0 3)*~. 'J' ~ 1i~ ~** .~ IK ~ .:E ~t 2 / 13.!ill] ~R- m~&lZIilt:rJlPlj~A~t:f:

t=rJ

2,5 0 0 p:j

J!

*

3;5

('lit

~

{j!,
ED
tm
0 3 - 9 9 1 - 3 7 54)

Transactions and Proceedings of the PalaeontologicalSociety of Japan
October 15, 1984

New Series No. 135

CONTENTS
TRANSACTIONS
782. Hu, Chung-Hung: Ontogenesis of Ehmaniella burgessensis Rasetti (Trilobita) fromBurgess Shale, Middle Cambrian, Yoho Park, British Columbia . . . . . . . . . . . 395
783. IBARAKI, Masako: Middle-Late Eocene planktonic foraminiferal faunas from limestones of the Setogawa Group, central Japan . . . . . . . . . . . . . . . . . . . . . . . 401
784. OMURA, Akio: Uranium-series age of the Riukiu Limestone on Hateruma Island,
southwestern Ryukyus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
785. TANAKA, Keisaku: Hemiasterid echinoids from the Upper Cretaceous of Japan .... 427