The Tadaki Limestone Quarry at Mikkabi is located near the northern tip of the Lake Hamana, about 20 kilometers northwest of Hamamatsu City on the Pacific coast of Central Japan (SUZUKI, Fig. 1). It is one of the quarries in the vicinity of Hamamatsu and is situated along the Paleozoic limestone belt which runs with a northeast trend from the Kii Peninsula to the Akaishi Mountains. Exposed in these quarries, many fossiliferous Pleistocene deposits are found filling the fissures and caves in the limestone.