Miocene molluscan fossils from the Akeyo Formation, Mizunami Group at the outcrop exposed during construction of Togari-Tsukiyoshi City Road in Mizunami City, Gifu Prefecture, Japan

Abstract

Molluscan fossils were collected from the lower Miocene Akeyo Formation (18 Ma) of the Mizunami Group at the outcrop exposed during the construction of Togari-Tsukiyoshi City Road in Akeyo-cho, Mizunami City. Minor Minolia tukiyosiensis (Oyama and Saka), “Pseudomurex?” tukiyosiensis Oyama and Saka, and Hiatula minoensis (Yokoyama) occur in a lenticular shell bed dominated by Crassostera sp. in the middle part of the Togari Member, Akeyo Formation. The oyster shells seem to have been transported and accumulated into the final depositional site from a small oyster reef within estuary environment by tidal or storm currents.