抄録
In the course of study of hill landform, it seems necessary to investigate not only the initial surface of the hill which is shown as accordant-height summits and is conceived to indicate a baselevel of erosion in an earlier age, but the processes of destruction or modification from initial surface into the present relief, the processes suggested, in the shapes of present valleys and slopes.
In the hilly land shown in Fig. 1, situated to the south of Sendai, there are two levels of accordant-height summits, HI and HII Levels. The Levels cut the Miocene Formation in the major part, and, in the minor part HI Level is underlain with weathered round gravel bed of the middle or lower Pleistocene. Above the summits of HI and HII Levels, protrude some peaks grouped into HI. Theose Levels are surrounded by a lowlying hill surface, HIII originated from the denudation surface formed prior to the fall of Yellow Pumice. Characteristic gentle slopes and shallow valleys were formed over whole area shown in Fig. 1, when the TI terrace formation proceeded. That terrace is correlated to the last low sea level by NAKAGAWA et al. (1960). Those slopes and valleys are in the surface forms continuous not only to TI but to the higher Levels especially to HI and they cut Yellow Pumice Bed, Such landforms, judged from their geological and morphological features, seem to be mainly formed with a kind of mass-movement on the valley-sides. Gentle slopes here may be Cryopediment by WAKO (1963). Through the formation of such geomorphological elements, Coarsetexthred landscape (COTTON, 1963) was arranged over the whole area, later some parts are reduced into Fine-textured landscape (COTTON, op. cit.) through the V-shaped valley formation. The Coarse-textured landscape is preserved better where the local baselevel is high. Throughout those processes, geological structure has continuously influenced the lartdform development and certain tectonic, movements took place even after the formation of TI surface.
