[in Japanese]

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The continental shelf of the western part of Tsugaru Strait consists of three terraces, one shallower than 20 meters, one 25 to 50 meters, and one 90 to 140 meters depth. Terrace, shallower than 20 meters, has been built by deposition or abrasion concerning present sea level along the coasts.
The terrace, 25 to 50 meters, which is incised by drc wned valleys, continues to the base of alluvial deposits which is measured about 8 meters thickness nar the coasts.
The slope, 50 to 90 meters, shows gentle-sloping surface, on which rocks and gravels are exposed extensively. This slope is concordant with the seaward extention of the upper coastal plain. On the other hand, this slope continues to the terrace, 90 to 140 meters. These three surfaces, the upper coastal plain, the submarine slope 50 to 90 meters and the submarine terrace 90 to 140 meters, appear to be a contenporaneous surface, and a portion of this surface (the upper coastal plain and the submarine slope) are formed by the up-warping of the west coast of Oshima Peninsula. Because, these two geomorphic surfaces distribute only around the western coast of Oshima Peninsula, where the axis of the up-warping is found.
The distribution of sediments on the shelf of the western part of Tsugaru Strait are related to the current. Also the distribution of the maximum diameter of gravels are influenced by the current. But, gravels on the terrace, 90 to 140 meters, are resemble to the deposits of the upper coastal plain. In spite of the discontinuity by the presence of cardrons and furrows between the shelf of the side of Hokkaido and Honshtl, gravels are composed by granite, the distribution of which is restricted on Oshima mountains in this region, and are found on the shelf of the side of Honshu.
Therefore, it seems that in the time of the formation of the terrace, 90 to 140 meters, continental shelf between Hokkaido and Honshu were continueos and gravels on the terrace were deposited luring the same time.

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In general, a decrease in stream flow (water level) in river-falling stage is accompanied by decrease in load concentration. But, looking over the state of the concentration change in detail, water level that abnormally have a great deal of concentration for a short time were observed several times. It has been considering, that this phenomenon is caused by the influence of the confluent tributaries.
Observation on the River Arakawa in Saitama showed, however, that it is caused particularly by avariance of the secondary (helical) flow motion. Also, the water level emerging notably variable of its motion was about 3 meters on the surveyed are a. In such a water level, concentration of suspended load become abnormally high, because of an influence, the writer thinks, on the increase of the drag force due to turbulence of stream line and on the variance of environment affecting the river bed.

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Sakata, Niigata and Naoetsu are neighboring three ports, which stituated along the coast of the Japan Sea, and have the same physical conditions as follows:
a) They are all estuary harbours.
b) It is necessary that they should always be dredged so as to maintain the depth of water.
c) Vessels neter the harbours from NNE to SSE. The wind blows very hard in the monsoon season, and so it is sometimes very dangerous for the small-sized vessels to enter them.
d) Thus, the right bank of the each estuary is only used.
A good port must have the modernized industrial area in its hinterland, to which a port is closely connected. Though these three ports have their manufacturing districts of heavy and chemical industries nearby, they are not closely connected with them.
Sakata and Naoetsu are used only by a few factories in their neighbourhood. Many factories in Yamagata and Niigata Prefectures do not use those ports to export or import their raw materials and products.
In this respect, Niigata has characters of the industrial port, and its hinterland stretches over the East Japan (Fig. 1).
It fulfils its function enough as a modernized and internatinoal trade port, but it is smaller in scale than any other main ports along the Pacific Ocean. Exports and imports are done dy the railway transportation which faced difficulties of overload at present.
The reason why the industries are not closely connected with the ports on the coast of the Japan Sea is that the ocean freight is higher than the overland freight, and that it lacks such special tonnage as large sized vessels or supertankers which demands the best ports facilities. The present difficulties in the railway transportation must be removed by the improvement of the facilities of these ports.

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