Wakkanabi Formation, Ishikari Group - Yurabi district (Eocene of Japan)

Where: Japan (43.5° N, 142.0° E: paleocoordinates 46.7° N, 136.4° E)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Wakkanabi Formation (Ishikari Group), Lutetian (47.8 - 41.3 Ma)

• STRATIGRAPHIC RELATIONS: From Wakkanabi Fm, which overlies the Yubari and underlies the Bibai Fm, all of the Ishikari Gp (Middle Eocene). THICKNESS: From unit which reaches a thickness of 100-250 m. AGE: early Middle Eocene according to Takano and Waseda (2003). Referred only to Eocene in Mizuno (1964). STRATIGRAPHIC POSITION: Composite checklist for formation from local area.

• formation-level stratigraphic resolution

Environment/lithology: coastal; lithified sandstone and lithified siltstone

• ENVIRONMENT: Marine and non-marine faunal assemblage.
• SPECIFIC LITHOLOGY: Sandstone and siltstone. LITHIFICATION: Assume to be lithified on the basis of age and photgraphic plates of Takano and Osamu (2003).

Size class: macrofossils

Preservation: cast, mold/impression

Collection methods: COLLECTOR: T. Mizuno (c. 1960's). REPOSITORY: Unknown, not stated in text.

Primary reference: A. Mizuno. 1964. Summary of the Paleogene molluscan faunas in North Japan. Geological Survey of Japan Report 207 [A. Hendy/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 70901: authorized by Austin Hendy, entered by Austin Hendy on 11.04.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for bivalvia and gastropoda. NOMENCLATURE: Somewhat antiquated, but with species-level identifications.
Bivalvia
 Ostreida - Ostreidae
Ostrea eorivularis Oyama and Mizuno 1958 oyster
 Carditida - Crassatellidae
"Crassatellites yessoensis" = Crassatella
"Crassatellites yessoensis" = Crassatella clam
 Carditida - Carditidae
Venericardia otatsumei Uozumi 1955 clam
 Pholadida - Myidae
"Mya ezoensis" = Mya (Arenomya) ezoensis
"Mya ezoensis" = Mya (Arenomya) ezoensis Nagao and Inoue 1941 softshell clam
 Cardiida - Veneridae
Pitar sorachiensis Oyama and Mizuno 1958 venus clam
 Cardiida - Mactridae
Spisula sorachiensis Otatsume 1933 clam
Gastropoda
 Neotaenioglossa - Calyptraeidae
Calyptraea sorachiensis Oyama and Mizuno 1958 slipper shell