Middle Permian ammonoids from the Takakurayama area, Abukuma Mountains, northeast Japan, and their stratigraphical significance

Four ammonoid species, Propinacoceras sp., Agathiceras sp., Mexicocerasl sp. and Roadoceras sp., are described from the upper Takakurayama Formation in the Takakurayama area, Abukuma Mountains, northeast Japan. These ammonoids indicate a Middle Permian (Wordian) age. The Takakurayama ammonoid specimens are reworked fossils, probably derived from shallow marine continental shelf to a deep-sea basin by sediment-gravity flows in Late, Permian.