Where: Japan (43.5° N, 142.0° E)
• Paleocoordinates: 50.4° N, 135.5° E (Wright 2013)
• coordinate based on nearby landmark
• local area-level geographic resolution
When: Akabira Formation (Ishikari Group), Bartonian (41.3 - 38.0 Ma)
• STRATIGRAPHIC RELATIONS: From Akabira Fm, which overlies the Bibai and underlies the Ikushunbetsu Fm, all of the Ishikari Gp (Middle Eocene). THICKNESS: From unit which reaches a thickness of 350-600 m. AGE: late 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
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 70903: authorized by Austin Hendy, entered by Austin Hendy on 11.04.2007
Creative Commons license: CC0 (CC0)
Taxonomic list
unclassified | |
Gastropoda | |
"Siphonalia" ishikariensis true whelk
"Siphonalia" sakakurai Mizuno 1954 true whelk | |
Nekewis sekii snail | |
Polinices ? nagahamai moon snail | |
Bivalvia | |
Acila shimoyamai Oyama and Mizuno 1958 divaricate nutclam | |
Yoldia hokkaidoensis clam | |
Modiolus ishikariensis mussel
Brachidontes ogasawarai mussel | |
Ostrea eorivularis Oyama and Mizuno 1958 oyster | |
"Margaritifera perdahurica" = Pinctada
"Margaritifera perdahurica" = Pinctada pearl oyster | |
Unio uryuensis freshwater mussel
Anodonta subjapanensis freshwater mussel | |
"Crassatellites yessoensis" = Crassatella
"Crassatellites yessoensis" = Crassatella clam | |
"Venericardia cf. yoshidai" = Cyclocardia yoshidai
"Venericardia cf. yoshidai" = Cyclocardia yoshidai Nagao 1928 clam | |
"Thyasira bisecta" = Conchocele bisecta
| |
"Microcallista munroei" = Callista (Microcallista)
"Microcallista munroei" = Callista (Microcallista) venus clam | |
"Geloina hokkaidoensis" = Polymesoda (Geloina), Corbicula tokudai
"Geloina hokkaidoensis" = Polymesoda (Geloina) clam
Corbicula tokudai clam | |
"Mya ezoensis" = Mya (Arenomya) ezoensis
"Mya ezoensis" = Mya (Arenomya) ezoensis Nagao and Inoue 1941 softshell clam COMMENTS: Includes Mya ezoensis akabirensis
| |
Periploma teshimai clam | |
Thracia sekii clam |