Molluscan fossils from the middle Miocene in Kenbuchi-cho, northern Hokkaido, and their significance

Abstract

Twelve molluscan species were identified from the middle Miocene in Kenbuchi-cho, northern Hokkaido, which is assigned to the Denticulopsis lauta Zone NPD A, . -. Ma . The molluscan assemblage includes some warm-water taxa such as Glycymeris cisshuensis and Liracassis japonica. The occurrence of the warm-water taxa indicates that warm water mass prevailed in northern Hokkaido. According to the molluscan evidence, northern Hokkaido was in a temperate marine zone during the early middle Miocene.