三浦半島葉山層群下部から産出した珪藻化石

抄録

Fossil diatoms were found from the Morito and Abuzuru Formations of the lower part of the Hayama Group in Miura Peninsula, central Japan. The presence of Crucidenticula sawamurae, Delphineis kamenooensis and Medialia splendida s.1. and the absence of Crucidenticula kanayae suggest that the age of all sample horizons of the two formations ranges from 17.8 to 16.9 Ma (the upper part of the Early Miocene C. sawamurae Zone). This age is much younger than that of the basal part of the Hota Group in Boso Peninsula, central Japan.