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

• STRATIGRAPHIC RELATIONS: From Bibai Fm, which overlies the Wakkanabi and underlies the Akabira 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: marginal marine; 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 70902: authorized by Austin Hendy, entered by Austin Hendy on 11.04.2007, edited by Bethany Allen

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for bivalvia and gastropoda. NOMENCLATURE: Somewhat antiquated, but with species-level identifications.
Angiospermae
 Malpighiales - Salicaceae
Populus sp. Linnaeus 1753 poplar
 Mesangiosperms - Arecaceae
 Laurales - Lauraceae
Cinnamomum sp. Schaeffer 1760 cinnamon
 Coniferales - Cupressaceae
Glyptostrobus sp. Endlicher 1847 Chinese swamp cypress
Taxodium distichum Linnaeus 1753 bald cypress
Sequoia langsdorfii Heer 1877 coast redwood
Gastropoda
 Architaenioglossa - Viviparidae
Paludina sp. FĂ©russac 1812 snail
Bivalvia
 Ostreida - Pteriidae
"Margaritifera perdahurica" = Pinctada
"Margaritifera perdahurica" = Pinctada pearl oyster
 Ostreida - Ostreidae
Ostrea eorivularis Oyama and Mizuno 1958 oyster
 Mytilida - Mytilidae
"Modiola sp." = Modiolus Lamarck 1801 mussel
 Cardiida - Corbiculidae
 Unionida - Unionidae
Unio sp. Philipsson 1788 freshwater mussel
Reptilia
 Testudines - Testudinidae
Sinohadrianus ezoensis n. sp. Shikama 1953 turtle
Unnumbered specimen in Institute of Geology and Mineralogy, Hokkaido University (holotype), carapace. Collected from "incline No. 19" at the Utashinai Coal Mine.