Inuwaka, Unakami-gun, Simosa Province (Pliocene of Japan)

Where: Japan (35.7° N, 140.9° E: paleocoordinates 36.2° N, 140.3° E)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Naarai Formation, Piacenzian (3.6 - 2.6 Ma)

• From the "Brachiopod-Crevices" which are cut into the Paleozoic rocks. The Inubo Group (of which the Naarai Fm is the basal part) on the Choshi peninsula is composed of marine deposits with a thickness of about 500 m. The depositional age of the group has been estimated at 3.2 Ma to 0.4 Ma from nannofossil biostratigraphy (Nishida 1980; Fujioka & Kameo 2004), magnetostratigraphy (Niitsuma 1970; Sakai 1990), and widespread tephras (Fujioka & Kameo 2004; Tamura et al. 2006). Over 50 tephra beds are intercalated in this group (Sakai 1990; Fujioka & Kameo 2004). Naarai Fm spans the Plio-Pleistocene boundary (ranging from Piacenzian to Gelasian) (Satoguchi & Nagahashi 2012), but this locality is from the lower part.

• group of beds-level stratigraphic resolution

Environment/lithology: marine; poorly lithified, tuffaceous, blue sandstone

• "fairly deep water"
• Bluish, soft tuffaceous or sandy rock

Size class: macrofossils

Primary reference: K. M. Hatai. 1940. The Cenozoic Brachiopoda of Japan. Science Reports, Tohoku Imperial University, Series 2 20:1-413 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 190821: authorized by Matthew Clapham, entered by Matthew Clapham on 18.12.2017

Creative Commons license: CC BY (attribution)

Taxonomic list

 Terebratulida - Dallinidae
Dallina simosensis Hatai 1940
 Terebratulida - Laqueidae
Laqueus quadratus Yabe and Hatai 1934
Laqueus kosibensis Hatai 1936
 Terebratulida - Terebratulidae
Gryphus angularis Hayasaka 1922
Gryphus radiata Hatai 1936
 Terebratulida - Cancellothyrididae