THE RELATION BETWEEN THE WESTERN PART OF TAMA HILLS AND THE ANCIENT SAGAMI RIVER

Abstract

The “Gotentoge” gravel bed found on the hill tops of the western part of Tama hills to the south of Hachioji, Tokyo, consists of polygenetic gravels, which seem to have been transported and deposited by the ancient Sagami River, because there exists the lithologic similarity of gravels between the “Gotentoge” gravel bed and the present Sagami River, and also because the gravels of the “Gotentoge” gravel bed become larger as they approach the present Sagami River (Fig. 3). There are some other evidences to prove it.
The upper surface of the “Gotentoge” gravel bed is almost horizontal, and covered conformably with the old Kanto volcanic ash member at Terazawa (loc. 4 in Fig. 3), but their stratigraphic relation is almost contemporaneous in the Gotentoge pass.
Therefore, the geologic age of the Gotentoge gravel bed is nearly the same with the Kanto volcanic ash member which belongs to the lower Diluvium.
Many questions, however, remain unsolved for further study.