Oguwa Formation, Chikanaga area (Cretaceous of Japan)

Where: Japan (33.3° N, 132.8° E)

• Paleocoordinates: 39.1° N, 136.8° E (Wright 2013)

• local area-level geographic resolution

When: Oguwa Formation (Shimanto Group), Turonian (93.9 - 89.8 Ma)

• STRATIGRAPHIC RELATIONS: From the Oguwa Fm (Turonian) of the lower Shimanto Group and Shimanto Supergroup, overlying the Shimoono Fm (Middle and Upper Albian) and overlain by the Furushiroyama Fm (Coniacian). AGE: Turonian. STRATIGRAPHIC POSITION: List not specified to any part of the formation.

• formation-level stratigraphic resolution

Environment/lithology: offshore; siliciclastic sediments

• STRATIGRAPHY and STRUCTURE: The Shimanto Supergroup is a thick clastic sequence with minor basic volcanic rocks, chert and limestone. The Aptian, Albian, Turonian, and Conacian to Santonian strata are in fault contact with one another. The Lower Cretaceous, except for the Lower Aptian is regarded as rather deep offshore deposits, while the Upper Cretaceous as neritic, shelf deposits.
• SPECIFIC LITHOLOGY: Lithology, unknown, presumably siliciclastic. LITHIFICATION: No evidence for lithification.

Size class: macrofossils

Collection methods: COLLECTOR: Collector unknown. REPOSITORY: Repository unknown.

Primary reference: Y. Teraoka, I. Obata, and I. Mizuno. 1980. Stratigraphy of the Shimanto Supergroup in the Chikanaga area, west Shikoku, with special reference to the Miyakoan and Gyliakian Series. Bulletin of the Geological Survey of Japan 31(7):307-319 [A. Hendy/A. Hendy]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 65022: authorized by Austin Hendy, entered by Austin Hendy on 18.09.2006

Creative Commons license: CC0 (CC0)

Taxonomic list

• COVERAGE: Suspected to only include biostratigraphically important taxonomic groups (i.e. inoceramids and ammonoids). NOMENCLATURE: Not an authoritative publication, but using subgeneric and species-level designations.
Show authors, comments, and common names
Malacostraca
 Decapoda - Palinuridae
Linuparus aff. japonicus
Linuparus aff. japonicus Nagao 1931 spiny lobster
Cephalopoda
 Ammonitida - Tetragonitidae
Anagaudryceras cf. limatum
 Ammonitida - Acanthoceratidae
Romaniceras ? sp., Romaniceras cf. deverioides
Romaniceras ? sp. Spath 1923 ammonite
Romaniceras cf. deverioides de Grossouvre 1889 ammonite
 Ammonitida - Collignoniceratidae
Subprionotropis cf. muramotoi
 Ammonitida - Desmoceratidae
Mesopuzosia sp.
Mesopuzosia sp. Matsumoto 1954 ammonite
 Ammonitida - Nostoceratidae
Eubostrychoceras ? sp.
Eubostrychoceras ? sp. Matsumoto 1967 ammonite
 Ammonitida - Scaphitidae
"Otoscaphites (Otoscaphites) puerculus" = Yezoites puerculus, "Otoscaphites (Hyposcaphites) cf. perrini" = Yezoites perrini, "Otoscaphites sp." = Yezoites
"Otoscaphites (Otoscaphites) puerculus" = Yezoites puerculus Jimbo 1894 ammonite
"Otoscaphites (Hyposcaphites) cf. perrini" = Yezoites perrini Anderson 1902 ammonite
"Otoscaphites sp." = Yezoites ammonite
 Nautilida - Nautilidae
Cymatoceras sp.
Cymatoceras sp. Hyatt 1884
Gastropoda
 Sorbeoconcha - Naticidae
Gyrodes sp.
Gyrodes sp. Conrad 1860 moon snail
Bivalvia
 Myalinida - Inoceramidae
"Inoceramus cf. incertus" = Mytiloides incertus, Inoceramus sp., Inoceramus tenuistriatus, Inoceramus cf. pedalionoides, Inoceramus cf. hobetsensis, Inoceramus cf. teshioensis
"Inoceramus cf. incertus" = Mytiloides incertus Jimbo 1894 clam
Inoceramus sp. Sowerby 1814 clam
Inoceramus cf. hobetsensis Nagao and Matsumoto 1939 clam
Inoceramus cf. teshioensis Nagao and Matsumoto 1939 clam
 Lucinida - Lucinidae
Lucinoma ? sp.
Lucinoma ? sp. Dall 1901 clam
Echinoidea
 Spatangoida - Hemiasteridae
Hemiaster uwajimensis