抄録
There are Katchi Hill to the west and Misawa Hill to the east of Lake Ogawara.
Katchi Hill is composed of the Pleistocene Enokibayashi Formation underlain unconformably by the Tertiary Katchi Formation. Shichihyaku (60-80m) and Furumaki (45-55m) Surfaces were formed at the lower sea-level.
Misawa Hill is composed of the Misawa Formation underlain unconformably by the Enokibayashi Formation, and the upper (35-40m), the middle (25-30m), and the lower (10-20m) surfaces were cut at the lower sea level and uplifted.
At the sea-level lowering during the Würm Glacial, three levels of river terraces were formed along the lower course of the Shichinohe River. Their seaward parts were submerged under the higher sea-level of Jômon age, which approximately accords with the stage of Flandrian transgression. Then, Lake Ogawara was blocked a little at the lower sea-level.
These two hills look as if they were under the same morphogenesis, however, Misawa Hill has the quite new origin.
