Memoir of the Fukui Prefectural Dinosaur Museum 14: 1–9 (2015)

ARTICLE© by the Fukui Prefectural Dinosaur Museum

SEDIMENTARY ENVIRONMENT OF DINOSAUR FOSSIL BEARING
SUCCESSIONS OF THE LOWER CRETACEOUS KITADANI FORMATION,TETORI GROUP, KATSUYAMA CITY, FUKUI, JAPAN
Shigeyuki SUZUKI1, Masateru SHIBATA2, 3, Yoichi AZUMA2, 3, Hirokazu YUKAWA3,
Toru SEKIYA3 and Yuto MASAOKA1
1
2

Department of Earth Science, Okayama University, Okayama, Okayama 700-8530, Japan
Dinosaur Research Institute, Fukui Prefectural University, Eiheiji, Fukui 910-1195, Japan
3
Fukui Prefectural Dinosaur Museum, Katsuyama, Fukui 911-8601, Japan

ABSTRACTThe Lower Cretaceous Kitadani Formation, Tetori Group in the Kitadani Quarry yields a large quantity of nonmarine fossils including dinosaurs. The quarry has large exposure with westward and northward facing surfaces, whichallow to analyze three-dimensional variations in composition and geometry. The successions at the quarry consist of
clastic rocks of the Point Bar Facies, the Abandoned Channel-ﬁll Facies and the Over Bank Facies. The sandy Point Bar
Facies is characterized by sheet like geometry and sedimentary structures caused by lateral accretion. The Abandoned
Channel-ﬁll Facies is mainly composed of ﬁne-grained sediments, which were considered to be deposited by suspension
fall-out. The depth of abandoned channel is as same as the thickness of the unit of the Point Bar Facies. The Over Bank
Facies is characterized by poorly sorted nature of deposits. Crevasse splay sandstones are frequent in the Over Bank
Facies. Sedimentary environment of an alluvial plain formed by meandering river is reconstructed.
Key words : sedimentary environment, alluvial plain, meandering river, Kitadani Formation, Tetori Group,
Lower Cretaceous

鈴木茂之・柴田正輝・東 洋一・湯川弘一・関谷 透・正岡祐人（2015）福井県勝山市，下部白亜系手取層
群北谷層の恐竜発掘露頭から復元される堆積環境．福井県立恐竜博物館紀要 14：1‒9．
福井県勝山市の恐竜発掘露頭からは保存が良好な恐竜化石をはじめとする多様な化石を産出している．継続的な発掘によって露頭は拡大し，北向きと西向き及び一部南向きの法面全面に地層が露出している．この入り組んだ露頭形状は地層の三次元的な解析に好都合である．本研究の調査は 2013 年と 2014 年の発掘期間中に行われた．露出する白亜紀前期の北谷層は突州堆積相（淘汰の良い粗粒砂岩主体の厚さ 3〜5 ｍ程度のユニット），オーバーバンク堆積相（泥岩主体で泥質砂岩を挟む），放棄流路埋積相（泥岩主体で流路を充填する）からなる．突州堆積相の底は侵食性の明瞭な面で，この相を被うオーバーバンク堆積相とともに上方
細粒化をなす．突州堆積相には側方に地層が形成されたことを示す堆積構造がある．放棄流路埋積相は三日月湖があったことを示す．以上のことからこれらの地層が蛇行河川によって堆積したことが確認できる．

INTRODUCTION(Tamura, 1990; Yabe and Shibata, 2011). A number of various
dinosaur fossils has been discovered from the excavation site
together with turtles, crocodiles, ﬁshes, eggshells and footprints(Azuma, 2003). A continuous paleontological excavation
at the site have resulted in the discovery of new species ofdinosaur fossils such as Fukuiraptor kitadaniensis (Azuma andCurrie, 2000), Fukuisaurus tetoriensis (Kobayashi and Azuma,
2003), Fukuititan nipponensis (Azuma and Shibata, 2010)
and Koshisaurus katsuyama (Shibata and Azuma, 2015). The

The study site, the Kitadani Quarry, is located in Katsuyama
City, Fukui Prefecture, Japan (N 36゜7′, E136゜32 ′). Occurrenceof non-marine molluscan fossils and plant fossils has been known
Received June 25, 2015. Accepted November 30, 2015.
Corresponding author̶Shigeyuki SUZUKI
E-mail: zysuzuk*cc.okayama-u.ac.jp(The asterisk should be replaced by @)1

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S. SUZUKI, M. SHIBATA, Y. AZUMA, H. YUKAWA, T. SEKIYA AND Y. MASAOKA

Tetori Group (middle Jurassic to early Cretaceous)
Hida Metamorphic Rocks
Sangun Metamorphic Rocks
Nagasaki Metamorphic Rocks
Ryoke Metamorphic Rocks
Sanbagawa Metamorphic Rocks
Accretionary Complex of the Chichibu Belt
Accretionary Complex of the Shimanto Belt
Shear Zone ？
FIGURE 1. Location of the study site.

successions of the site belong to the Lower Cretaceous Kitadani
Formation of the Akaiwa Subgroup, the uppermost subgroup of theTetori Group. General facies analysis of the Tetori Group wasstudied by Masuda et al. (1991) and marine to lacustrine, delta andﬂuvial environments were reconstructed. Okazaki and Isaji (2008)
analyzed sedimentary facies of the Kuwajima Formation andinterpreted that the successions deposited in bay, bird-foot delta
and meandering river environments. Sedimentary environment of
the Kitadani Formation was studied by Masuda et al. (1991) as an
excursion guide without critical descriptions for facies. Yabe andShibata (2011) studied plant fossil Brachyphyllum of the Kitadani
Quarry and obtained depositional environment of the fossil bedsof plant fossils as a floodplain of meandering river together
with observation of facies. However studied facies are limitedin the fossil bed. Aim of this study is to understand depositional
environment of the succession of the Kitadani Quarry. The
outcrop of the Quarry with virtually complete exposure wassketched during the dinosaur excavation project in 2013 and2014. Observations of facies on polished cross sections of hand
specimens and thin sections under microscope are also performed.
As emphasized by Miall (1985), three-dimensional observation
was done to describe facies. The successions are considered
to be a meandering river deposits which are characterized byﬁning upward unit with sharp base (Allen, 1964). Informationfrom fossil beds provides very detail reconstruction of

paleoenvironments. Facies analysis of individual fossil beds isunder investigation and will be published later.
GEOLOGICAL SETTING
The study area (the Takinami River area) is situated in the Hida
Belt, distributed in Japan Sea side of Central Japan (Yamashita,1957). The Hida Belt was a part of the Eurasian Continent in preMiocene and is composed of the Pre-Cambrian metamorphic andlower to middle Jurassic granitic basement and Middle Jurassic to
Lower Cretaceous sedimentary covers of the Tetori Group (e.g.,Suwa, 1990) which yield dinosaur fossils (Figs. 1, 2). The Hida
Belt is separated by a large shear zone, often called the Hida-gaien
Belt, from the major part of the Japan island arc.
The Tetori Group is generally subdivided into three subgroups;
the Kuzuryu, Itoshiro and Akaiwa subgroups in ascending order(Maeda, 1961), but only the Akaiwa subgroup is distributed inthis area (Maeda, 1958). The Lower Cretaceous Akaiwa Subgroupin this area comprises lower Akaiwa Formation and upper
Kitadani Formation (Maeda, 1958) and the upper part of the latterformation is exposed in the Kitadani Quarry (Fig. 3).
SEDIMENTARY FACIESThe sediments exposed in the Quarry are subdivided into PointSEDIMENTARY ENVIRONMENT OF THE KITADANI QUARRY

3

Sketch area of Fig. 6aSketch area of Fig. 5a

Sketch area of Fig. 4a

FIGURE 2. Outcrop of the Kitadani Quarry, showing the sketch parts.

Bar Facies, Abandoned Channel-ﬁll Facies and Over Bank Facies(Figs. 4a, 5a, 6a).
Point Bar Facies

FIGURE 3. Stratigraphy of the Tetori Group.

This facies is composed of gravel sandstone subfacies (GS)and coarse- to medium-grained sandstone subfacies (CMS).
White colored sandstones of the Point Bar Facies are easy to be
distinguished from darker sediments of another facies. The baseof the facies has sharp bottom erosion surface. The parallel planar
layer of the facies continues laterally more than 80 m with 3 to
5 m in thickness.
Gravel sandstone subfacies (GS): This subfacies is mainlycomposed of coarse-grained sand and minor granule to pebble size
clasts (Fig. 4b). Gravel clasts are rounded to subrounded and arecomposed of siliceous durable rocks. The GS is limited in at thebase of the Point Bar Facies. The bases of the GS are sharp and inplaces erosional (Fig. 4b, c). The boundary between GS and CMS
is not sharp.
Coarse- to medium-grained sandstone subfacies (CMS):
Well to moderate sorted, coarse- to medium-grained sandstone
characterizes the CMS. Large scale epsilon cross-stratification(Fig. 4c) and trough cross-stratification (Fig. 4d) are typicalstructures. In Figure 5a, two types of trough cross-stratification
are recognized, type A and type B. A geometry of the type A
trough cross-stratification is observed in the section of Figure 5a.

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S. SUZUKI, M. SHIBATA, Y. AZUMA, H. YUKAWA, T. SEKIYA AND Y. MASAOKA

In longitudinal East to West (EW) section, the trough crossstratification appear as large scale cross-stratification (Fig. 5a,c). Trough structures are obvious in transverse North to South(NS) section (Fig. 5b). The sandstone indicates mainly troughcross-stratiﬁcation with basal ﬁner-grained laminated thin layer.
The thin layer is composed of ﬁne- to coarse-grained laminatedsandstone of a few centimeters in thickness or thin millimeterscale layer of plant fragments. Type B trough cross-stratiﬁcationis composed of medium- to coarse-grained sandstone with well
to moderate sorting (Fig. 4d). In the trough cross-stratiﬁcation of
Figure 5a, red arrows indicate that the southern trough laminae
cut previous laminae. It indicates the unit was formed by lateralaccretion from north to south.
In the case of Figure 5a, the GS is lacking and the CMS has
sharp erosional base. Rip up shale clasts are common in the CMS(Fig. 4e). The sandstone of the CMS is characterized by a little
mud matrix under microscope (Fig. 4f). The composition of thesandstones is rich in quartz and feldspar and associated with mica
and felsic igneous and sedimentary rock fragments (Fig. 4f).
Abandoned Channel-fill Facies
This facies is subdivided into slumped mudstone and sandstone
subfacies (SMS), black clayey mudstone subfacies (BCM),
alternation of mudstone and sandstone subfacies (AMS) andorganic structureless mudstone subfacies (OSM). The Facies ﬁlled
up the channel structure (about 35 m in width and 7 m in depth)(Fig. 5a, b). The basal surface of the facies is sharp (Fig. 5a).
Slumped mudstone and sandstone subfacies (SMS): The
SMS covers the bottom and slope of abandoned channel. The
slope dips about 10 to 15 degrees to the bottom. Irregularly
deformed disrupted sand and mud lenses and layers are floatedin black clayey mudstone. Coarse- to fine-grained sandstonelenses have irregular shape. Tight slump folds with bottomward vergence are formed (Fig. 5d). Bivalve fossils are foundin mudstone and irregular balls and lenses of coarse-grainedsandstone (Fig. 5e).
Black clayey mudstone subfacies (BCM): The BCM
is mainly composed of organic black clayey mudstone andcharacterized by silt-laminated mudstones and thin parallel
continuous ﬁne-grained sandstone layers. Intercalated parallel tolenticular ﬁne-grained sandstone layers are 1 to 3 cm in thickness.
A few normally graded beds with minor erosional scour are found(Fig. 5f). Crude ripple structures are also found (Fig. 5g).
Alternation of mudstone and sandstone subfacies (AMS):
The AMS is composed of black clayey mudstone and 5 to 10 cm
planar parallel beds of ﬁne-grained sandstone (Fig. 5h). Parallel
lamination (Fig. 5i) in mudstone is common. Sandstone layers
comprise multiple structure, for example, normal grading, parallel
layer and convolute lamination in Figure 5j. The sandstone layers
dips toward center of the channel and form large scale crossstratiﬁcation (Fig. 5a) which is the typical structure of the AMS.
Organic structureless mudstone subfacies (OSM): The OSM
is characterized by homogeneous structureless mudstone. The
mudstone is blackish due to high organic contents. It also contains

ﬁne- to medium-grained sand clasts. The fossil of dinosaur bones
and teeth, turtles and crocodiles, non-marine molluscan shells,
fish scales as well as plants (mainly leaves) and charophyte
gyrogonites were yielded in this subfacies. Most bivalve fossils
occurred as fragment of disarticulated valves but articulated
valves are also found (Fig. 5k).
Over Bank Facies
This facies is subdivided into parallel bedded sandstone
subfacies (PBS), lenticular sandstone subfacies (LS), black
mudstone subfacies (BM) and gray to green mudstone subfacies(GGM).
Parallel bedded sandstone subfacies (PBS): Darker
colored fine- to medium-grained massive sandstone layered
unit characterizes the PBS, which is intercalated in mudstone of
the Over Bank Facies (generally in the gray to green mudstone
subfacies) (Fig. 6a, b). The thickness of the unit is 10 cm to 1
m. The tops of the units vary from sharp to gradational. Foot
prints of dinosaurs are found on sharp upper surface of the layers.
Poorly sorted nature with mud matrix is quite different from thesandstone of the CMS of the Point Bar Facies (Fig. 6c).
Lenticular sandstone subfacies (LS): The sandstone isgrayish fine- to coarse-grained and moderately sorted. The LS
have two types of shapes: convex upward shape (Fig. 6d) andconvex downward shape. Convex upward type is 50 cm to 1 m
thick with cross laminae in some parts. This type occurred in theblack mudstone subfacies. Convex downward type, ca. 1 to 2 mthick with erosional bottom surface has also cross laminae. This
type of sandstone lenses are continued to the sandstone layer of
the PBS.
Black mudstone subfacies (BM): The BM is composed ofblack sandy mudstone and usually overlie the Point Bar Facies (Figs.
4a, 6a). The boundary with the Point Bar Facies is not sharp.
Parallel laminated ﬁne-grained sandstone layer (Fig. 6e, and P in
Fig. 6a), current rippled ﬁne-grained sandstone layer and poorly
sorted ﬁne- to medium grained sandstone lenses (10 to 30 cm inthickness) are observed. Many fossils were obtained from thissubfacies.
Gray to green mudstone subfacies (GGM): The subfacies ismainly composed of grayish to greenish colored sandy massive
mudstone. Discontinuous laminae of fine-grained sandstone areoccasionally intercalated. Clay mineral rich zone with calcareous
nodule characterize the GGM (Fig. 6f). Slaking caused by clay
mineral formation penetrates this subfacies (Fig. 6g).
SEDIMENTARY ENVIRONMENT OF THE SUCCESSIONSOF THE KITADANI QUARRY
Point Bar Facies
Erosive base of conglomerate and coarse-grained sandstonefollowed by coarse- to medium-grained sandstone, which isoverlain by mudstone, is a typical ﬁning-upwards unit of alluvial
deposit (Allen, 1965a). Well to moderately sorted sandstone isSEDIMENTARY ENVIRONMENT OF THE KITADANI QUARRY

5aFig. 4cFig. 4b

B

d

b

c

e

f

FIGURE 4. a, Sketch of the Point Bar Facies and Over Bank Facies of the Kitadani Quarry. Blank arrows indicate limits of the facies; b, Gravel sandstone
subfacies (GS) with sharp base.Width of view 40 cm; c, Epsilon cross-stratiﬁcation (arrows) of coarse- to medium-grained sandstone subfacies (CMS). Gravel
sandstone subfacies (GS) (about 10 to 20 cm in thickness) is at the bottom of the Point Bar Facies. Width of view 3 m; d, Type B trough cross-stratiﬁcationsof CMS (In the sketch of Fig. 5a). The trough laminae cut previous laminae (arrow). Width of view 4 m; e, Well sorted coarse-grained sandstone with shale
clast (arrows) of CMS. Width of view 5 cm; f, Microphoto of sandstone from CMS. Well sorted clasts with very poor mud matrix. Q: quartz, F: Feldspar, R:
Rhyolitic rock fragment. Width of view 1.8 mm.

considered to be deposited under continuous current. Crossstratiﬁcations indicate dunes formed by current. Jackson (1976)
described fining-upward sand unit with cross-stratifications
from the cutbanks and trenches in recent point bar of the lower
Wabash River. Large-scale epsilon cross-stratiﬁcation of the CMS
indicates that the subfacies were formed by a lateral accretion(Allen, 1970). The trough cross-stratiﬁcation of type B in Figure
5a are also considered to be deposited by lateral-accretion. Thesefeatures support that the units were formed by a meandering river.
The GS and CMS are considered to be channel lag and point bar
deposits respectively. Upper limit of the facies is almost horizontal
and swell structure (Nanson, 1980) described from Beatton River
was not remained. The upper part of the point bar is considered to
be rarely preserved as Plint (1983) suggested.

Abandoned Channel-fill Facies
Convex downward and channel ﬁll geometry of deposit is mostessential feature of the facies. And fine-grained lithofacies are
typical (Miall, 1996). The sharp contact between the Abandoned
Channel-fill Facies and the Point Bar Facies is also describedin the Middle Eocene of southern England (Plint, 1983). It isconsidered to be caused by rapid abandonment of the channel(Allen, 1965b). A mechanism of chute cutoff, which forms new
abandoned channel, is described by Constantine et al. (2010).
Irregularity of lenticular sandstone of the slumped mudstoneand sandstone subfacies (SMS) is considered to be caused bya syn-sedimentary deformation. The folds with bottom-wardvergence are regarded as slump folds. Plint (1983) reported a

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S. SUZUKI, M. SHIBATA, Y. AZUMA, H. YUKAWA, T. SEKIYA AND Y. MASAOKA

Fig. 5cFig.5bOSM

Over bank Facies

GGM

OSM

GGM

A
B
Abandoned Channel-fill Facies

SMS
Fig. 4d

Fig. 5d, eFig. 5k
Fig. 5hFig. 5f, g
SMS

BM

BM

a
b

e

h

i
c

f

j
d

g

k

FIGURE 5. a, Sketch of the three Facies in NS and EW direction cut of the Kitadani Quarry. A; type A trough cross-stratiﬁcation. B; type B trough crossstratiﬁcation; b, NS section of sketched outcrop in Figure 5a; c, EW section of sketched outcrop in Figure 5a; d, Slump fold of the slumped mudstone andsandstone subfacies (SMS). Arrows indicate hinges of tight slump fold; e, Bivalve fossils (arrows) in the SMS; f, Thin ﬁne-grained graded sandstone layer (G)and very thin layer of ﬁne-grained sandstone (T) in the black clayey mudstone subfacies (BCM). Lens cap 5 cm; g, Fine-grained sandstone layers in the BCM.
Arrows indicate crude ripples. Lens cap 5 cm; h, Alternation of mudstone and sandstone subfacies (AMS). Arrow 1: collecting point of the sample in Figure
5j. Arrow 2: collecting point of the sample in Figure 5i. Width of view 0.7 m; i, Polished sample of mudstone of the AMS. Parallel lamination of mudstone andsiltstone/ﬁne-grained sandstone. Width of sample 12 cm; j, Polished sample of sandstone of the AMS. Width of sample 7 cm. G; normal grading. C; convolute
lamination; k, Organic structureless mudstone subfacies (OSM) with non-marine molluscan fossils. Width of view 15 cm.

7

SEDIMENTARY ENVIRONMENT OF THE KITADANI QUARRY

aFig. 6eoFig. 6d

Fig. 6f

b

d

f

c

e

g

FIGURE 6. a, Sketch of the Over Bank Facies and Point Bar Facies of the Kitadani Quarry. Meshed black: fossil wood, P: horizon of parallel laminated ﬁnegrained sandstone; b, Parallel bedded sandstone subfacies (PBS) intercalated in gray to green mudstone subfacies (GGM); c, Microphoto of sandstone
from the PBS. O: plant fragment, M: mud matrix. Width of view 1.8 mm; d, Convex upward type of the lenticular sandstone subfacies (LS) which is cut by
the fossil stump. Width of view 4 m; e, Black mudstone subfacies (BM) with parallel lamination of ﬁne-grained sandstone. Width of view 50 cm; f, Gray togreen mudstone subfacies (GGM) with calcareous nodules (arrows). Width of view 1.5 m; g, Calcareous nodules (arrows) of the GGM. Slaking penetrates thissubfacies. Width of view 50 cm.

slump fold at the bottom of channel-plug . Lenses of coarsegrained sandstone were inferred to be derived from eroded CMS.
Bivalve fossils in the SMS were thought to be derived fromshallower part. The SMS is interpreted as a slump deposit on theslope and bottom of an abandoned channel.
Mud of the black clayey mudstone subfacies (BCM) is
considered to be transported by suspension. Limited ﬁne-grained
sand layers with normal grading were inferred to be deposited bywaning currents (Plint, 1983). Crude ripples indicate that there
were gentle current at the time.
The alternation of mudstone and sandstone subfacies (AMS)
is characterized by mudstone dominant fine-grained sediments.
Finely laminated mudstone is common in channel-fill deposits(e.g., Reineck and Singh, 1980) and considered to be depositedby suspension fall-out. The large scale cross-stratification
indicates that the unit of AMS was developed from the outer rim
to the center of the abandoned channel. The multiple structure ofsandstone layer indicates that a variation of transportation had
occurred.
Organic structureless mudstone subfacies (OSM) is
characterized by abundance and variation of fossil remains.
Obtained charophyte indicates very shallow pond environment.
Intertonguing relationship between OSM and the Over Bank
Facies suggests that there was boundary of water and dry surface.
Abundant plant fossils suggest an existence of vegetation. Fossilsof turtle and crocodile support a possibility of rich ecosystem.
The succession from SMS to OSM indicates that a lake ofabandoned channel was ﬁlled by sediments. The thickness of the

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S. SUZUKI, M. SHIBATA, Y. AZUMA, H. YUKAWA, T. SEKIYA AND Y. MASAOKA

succession is about 7 m, which is same as the Point Bar Facies. It
suggests that the type of stream cut-off is neck cut-off by Fisk
(1944, 1947).
Over Bank Facies
This facies overlay the Point Bar Facies. The succession fromthe sharp erosional base of the Point Bar Facies to the Over Bank
Facies forms a fining-upwards unit. The Over Bank Facies is
considered to be deposited in out of channel of river. Massive,
poorly sorted nature of the parallel bedded sandstone subfacies(PBS) indicates abrupt deposition. The sheet like geometry of
the PBS supports that the PBS deposited on a floodplain as a
crevasse-splay during flooding. The convex upward type of thelenticular sandstone subfacies (LS) was formed as a dune whichis thought to be deposited in the proximity of a channel. The
convex downward type of the LS is interpreted as a crevassesplay channel deposits. The black mudstone subfacies (BM) is
commonly associated with sandy layer (ripple laminated andparallel laminated sandstone layer), which suggest the effectof current. The LS is usually associated with the BM. The
association of BM and LS is interpreted to be deposited in a
proximal floodplain. Calcareous nodules and slaking nature of
the gray to green mudstone subfacies (GGM) suggest that the
GGM was affected by soil formation. Clay mineral rich zone withcalcareous nodule is considered to be a paleosol. It is interpreted
that the GGM was deposited on ﬂoodplain at a ﬂooding event andaffected by soil formation. The association of GGM and PBS isconsidered to be deposited in a distal ﬂoodplain.
As in the Figures 4 and 6, there is a tendency to overlay inorder from the Point Bar facies at the bottom, the BM with the LS
and/or the PBS and the GGM with PBS at the top. It indicates anenvironmental change from channel, proximal ﬂoodplain to distal
ﬂoodplain.
CONCLUSION
The sediments of the Kitadani Quarry demonstrate that there
were river channel and floodplain. In the channel, coarse- tomedium-grained sand with minor gravel were transported. Lateralaccretion of the Point Bar Facies indicates high sinuosity of theriver channel. Abandoned channel exists and crevasse splays arevery common. These features suggest the typical alluvial plain
formed by meandering river and the river might correspond to theclassic sandy meandering stream proposed by Miall (1985).
ACKNOWLEDGMENTS
We would like to thank Drs. Yoshikazu Noda, Shin-ichi Sano,
Kazunori Miyata, Tai Kubo and Teppei Sonoda of FPDM forvery useful comments during the ﬁeldwork. The manuscript was
greatly improved by helpful comments from Drs. Atsushi Yabeand Hiroko Okazaki.

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Formation, Fukui, central Japan. Zootaxa 3914 (4): 421–440.

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Akaiwa Formation …………… 赤岩層
Akaiwa Subgroup ……… 赤岩亜層群
Chichibu ………………………… 秩父
Fukui …………………………… 福井
Hida ……………………………… 飛騨
Itoshiro Subgroup …… 石徹白亜層群

9Suwa, K. 1990. Hida-Oki Terrane; pp.13–24 in K. Ichikawa, S.
Mizutani, I. Hara, S. Hada and A.Yao (eds.), Pre-Cretaceous
Terrane of Japan. Publication of IGCP Project No. 224: PreJurassic Evolution of Eastern Asia.
Tamura, M. 1990. Stratigraphic and palaeontologic studies on
non-marine Cretaceous bivalve faunas in Southwest Japan.
Memoirs of the Faculty of Education Kumamoto University
39, Natural Science (Supplement): 1–47. *Yabe, A., and M. Shibata. 2011. Mode of occurrence ofBrachyphyllum from the Lower Cretaceous Kitadani Formationof the Tetori Group in Fukui Prefecture, Central Japan, withreference to its paleoecology. Memoir of the Fukui Prefectural
Dinosaur Museum 10: 77–88. *Yamashita, N. 1957. Mesozoic. Chigakusousho 10, The Association
for the Geological Collaboration in Japan, Tokyo, 94 pp. *****地名・地層名: in Japanese with English abstract: in Japanese＞

Katsuyama ……………………… 勝山
Kitadani Formation …………… 北谷層
Kuwajima Formation ………… 桑島層
Kuzuryu Subgroup …… 九頭竜亜層群
Nagasaki ………………………… 長崎
Ryoke …………………………… 領家

Sanbagawa …………………… 三波川
Sangun …………………………… 三郡
Shimanto ……………………… 四万十
Takinami ………………………… 滝波
Tetori Group ……………… 手取層群