THE SEA OF JAPAN 



751 



In the southeastern part of the Sea there lies a large submarine range, 

 some of its elevations rising to within 300 to 400 m of sea-level. Moreover, in 

 different parts of the deep-water trench some summits rise to a height' of 

 1 ,500 to 2,000 m from the sea-floor. 



The bottom deposits of the Sea of Japan are mostly aleurites of varying 

 coarseness (Fig. 370). The complete absence of diatomaceous oozes from the 

 Sea of Japan is noteworthy, since they are exceptionally abundant in the Sea 

 of Okhotsk and the ocean adjacent to it. 



Almost the whole of the mainland coast of the Sea extends parallel to the 



Fig. 368. Characteristic peculiarities of the water 

 exchange of the Seas of Japan and of Okhotsk and 

 Bering with the Ocean. 



peaks of the Sikhote-Alin range. The coast there is fairly sheer and coastal 

 features are rare. The character of the coast changes greatly to the south 

 beyond Cape Povorotniy, and it runs at right angles to the axis of the Sikhote- 

 Alin range; its coastal features then become numerous. There are several 

 small, tortuous inlets and two large bays, those of Amur and Ussuriisky. 



The coast of Western Sakhalin differs greatly from the mainland coast. It 

 is composed of easily disintegrated chalk and Tertiary rock and has been 

 smoothed throughout most of its length by the process of abrasion. Former 

 river estuaries are filled with alluvium, and some estuaries jut out into the 

 Sea, forming small smooth, prominent deltas. Abrasion has markedly de- 

 creased now owing to the formation of a very wide beach along the coast. 

 Although the tide-range is small, the tidal zone is frequently wide. 



The Sea of Japan may be divided into two distinct parts according to the 



