1 It is difficult to explain the uniformity of the depth of shelf margin, in some various geological provinces, with the uniformity of the amount of the crustal movement in the Pleistocene Age.
2 The continental shelves around the Japanese Island are divided into two terraces which related to glacial eustasy during the late Pleistocene Ice Age.
3 During that time, the Japan Sea have continued lagoonal cond-ition, and the delta developed at the river mouth. These deltas consist of the continental shelves of the Japan Sea. Contrary, the Pacific side of the Japanese Islands, in many areas, the continental shelves are consisted of basal rocks which are exposed by marine erosion.
4 The time of shelf forming was between Elephas namadicies naumanni Makiyama and Mammonteus primiganius prinigenius Blumenbach, namely it was early Würm Ice Age.