On the Fossil Shells in the Nakatu Super-formation, developed in the Nakatu District, Kanagawa Prefecture, South Kanto, Japan

The stratigraphic succession of the rocks of the Nakatu district is as follows: (9) Alluvium (8) Kanto volcanic ash (7) Terrace deposite (6) Sioda pumiceous sandstone and mudstone (5) Otuka tuffaceous siltstone (4) Takadabasi sandstone and conglomerate (3) Kanzawa alternation of sandstone and siltstone (2) Kosawa sandstone and conglomerate (1) Kobotoke group Nakatu super-formation 1) Many fossil shells are allochthonous in the Kosawa and Kanzawa formations, but only a few are so in the other formations., 2) The Kosawa, Kanzawa and Takadabasi formations were deposited in the euneritic zones, but the Otuka and Sioda formations were formed in the mesoneritic or subneritic zones., 3) During the deposition of the Nakatu super-formation, the Kurosio current was more predominant than the Oyasio, except at several horizons., 4) At the beginning of the deposition of the Nakatu super-formation, the bottom-current were strong and at the end it became weak., The direction of the current is interpreted as S, SW, W, or WNW.,