Itchoda Fm - Amakusa (Eocene of Japan)

Where: Japan (32.4° N, 130.2° E: paleocoordinates 39.3° N, 125.4° E)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Itchoda Formation (Sakasegawa Group), Late/Upper Eocene (37.2 - 33.9 Ma)

• STRATIGRAPHIC RELATIONS: From Itchoda Fm, which locally overlies the Middle Eocene Toishi Fm, and underlies the Sakasegawa Fm (Late Eocene). THICKNESS: From member within formation that attains a thickness of ~10 m. AGE: Late Eocene, based on molluscan biostratigraphy. STRATIGRAPHIC POSITION: From unknown part of formation in this local area.

• group of beds-level stratigraphic resolution

Environment/lithology: coastal; lithified, glauconitic sandstone

• ENVIRONMENT: Shallow sea, soft-bottom siliciclastic bottom.
• SPECIFIC LITHOLOGY: Glauconitic sandstone. LITHIFICATION: Presumed lithified on the basis of age.

Size class: macrofossils

Collection methods: surface (float),

• COLLECTOR: A. Mizuno (c. 1964). REPOSITORY: Not stated in text, unknown.

Primary reference: A. Mizuno. 1964. Paleogene and Early Neogene molluscan faunae in West Japan. Geological Survey of Japan Report 204 [A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 70924: authorized by Austin Hendy, entered by Austin Hendy on 11.04.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for gastropoda and bivalvia. NOMENCLATURE: Farly modern nomenclature, and species-level assignments.
 Pectinida - Limidae
Lima nishiyamai file clam
Lima kumasoana file clam
Lima amaxensis Yokoyama 1911 file clam
 Carditida - Crassatellidae
"Crassatellites nipponensis" = Crassatella
"Crassatellites nipponensis" = Crassatella clam
 Carditida - Carditidae
"Venericardia mandaica" = Venericardia (Venericardia) mandaica Yokoyama 1911 clam
"Venericardia nipponica" = Venericardia (Venericor) nipponica Yokoyama 1911 clam
 Cardiida - Veneridae
 Pholadomyida - Pholadomyidae
"Pholadomya "margaritacea"" = Pholadomya (Bucardiomya) margaritacea
"Pholadomya "margaritacea"" = Pholadomya (Bucardiomya) margaritacea Sowerby 1821 clam