854 T. BELT ON THE STEITES OF SOUTHERN RUSSIA. 



Tylor in ascribing this lower level of the rivers to a general de- 

 pression of the surface of the ocean, caused in the Glacial period 

 by so much water being locked up, in the form, of ice, above the 

 level of the sea. 



The next stage represented is that of the fluviatile beds at the 

 base of the diluvial clay, containing recent species of freshwater 

 shells and the remains of the Mammoth, These beds at Taganrog 

 graduate upwards into the diluvial clay, of which, indeed, they form 

 the basement. Beds of similar age in Bessarabia are considered by 

 Dr. Peters also to be truly intercalated with the loess. It will 

 therefore be convenient to discuss the origin of the fluviatile beds 

 along with that of the diluvial clay. It seems scarcely doubtful 

 that the conclusion of Murchison is correct, that the diluvial clay is 

 the continuation southward of the northern drift. Nor do I see 

 how it can be disputed that it is also the continuation and equiva- 

 lent of the loess of the Danube. The bones of the Mammoth and 

 the Woolly Rhinoceros occur in each of the areas, and, in every case 

 that I know, only in the basement-beds of the deposits that I sup- 

 pose to be contemporaneous. We are assured, not only by the 

 occurrence of these mammals, but by the transport of the erratic 

 blocks of Russia, that the deposits belong to the Glacial period; 

 and in considering the question of their origin we are able at once 

 to show that some of the theories that have been proposed to account 

 for the formation of similar diluvial beds in other parts of the world 

 fail when applied to those of Russia. Thus the Baron P. von Richt- 

 hofen has suggested that the loess-like clays of the north of China 

 have been formed from clouds of dust blown by the wind*. In Russia, 

 even if we could imagine a whole country to be covered by thick 

 beds of clay formed of dust blown from some unknown region, we 

 should still leave unexplained the transport of the northern blocks 

 for hundieds of miles across the plains. Even for the formation of 

 the loess of the Rhine and the Danube the theory is unsatisfactory ; 

 for the land-shells contained in it are generally those that belong to 

 damp places and climates, and the species that frequent dry and 

 sunny spots are scarce. Again, some geologists have ascribed the 

 outspread of diluvial deposits to great floods, produced, according to 

 Mr. Alfred Tylor, by more abundant rains than now occur, or, 

 according to Dr. Dana and Dr. Haast, by the melting of the ice- 

 sheet at the close of the Glacial period. But the diluvial clay of 

 Russia extends from the Carpathians to the Urals, covers the water- 

 shed between the rivers that drain to the north and those that drain 

 to the south, and is entirely independent of the great river-valleys. 

 The northern blocks have also been carried in the opposite direction 

 to the flow of the northern rivers, and stranded on the flanks of the 

 Carpathians up to heights of 1200. feet above the sea, and even 

 higher. 



We thus have the question narrowed down to one of two issues 

 only. We require a great sea of water for the flotation of the ice- 



* Report on the Provinces of llonan and Shansi. 1870. 



