686 



BIOLOGY OF THE SEAS OF THE U.S.S.R. 



was very complex, and it is still not sufficiently known. Was there a period of 

 complete isolation of the Sea of Japan from the Ocean, and were its waters 

 then fresh? Is H. Yabe's (1929) hypothesis true (Fig. 327)? Were the basins 

 of the Okhotsk and Bering Seas dry land at the beginning of the Quaternary 



PRESENT-DAY DRY LAND 



INCREMENT OF DRY LAND AT THE BE- 

 GINNING OF THE QUATERNARY EPOCH 



INLAND BASINS ON SITES OF PRESENT- g|^= 

 DAY ADJACENT SEAS 



PACIFIC OCEAN AT THE BEGINNING OF 

 QUATERNARY EPOCH 



Fig. 327. Mainland relief of Far Eastern Seas at the beginning of the Quaternary 



period (H. Yabe). 



Period and to what period should the appearance of their deep trenches be 

 ascribed? 



G. Lindberg's series of works on the palaeogeographic past of the north- 

 western part of the Pacific (1948, 1953, 1956) are most interesting. An 

 examination of the contemporary geographical distribution of fresh-water fish 

 has led this worker to the conclusion that in the recent geological past some 

 river systems now cut off from each other by the sea were then linked through 

 areas of the mainland which are now submerged. The examination of the 

 contemporary bottom topography of the Far Eastern Seas led Lindberg to the 



