858 T. BELT ON THE STEITES OF SOUTHERN ET7SSIA. 



as the ice of the Atlantic and the Pacific more effectually block- 

 aded the northern outlets of the basin. This stage is well maiked 

 in Northern Germany by the wide-spread sands, with freshwater 

 shells, that lie at the base of the Lower Boulder-clay between the 

 Oder and the Elbe. 



The fluviatile beds gradually merge upwards into more silty 

 strata, and finally into the unstratified diluvial clay. The waters 

 were now charged with muddy sediment, the presence of which and 

 its copious deposition probably caused the destruction of the fresh- 

 water mollusks over most of the area submerged. Another more 

 important break in the succession of life is well marked in Russia. 

 Both in the north and in the south of that country the bones of the 

 Mammoth and its associates are found only at the base of the dilu- 

 vial beds. In Western Europe they occur both in the same posi- 

 tion and in the overlying " Middle Glacial Sands and Gravels." 

 As when found in the latter formation they occur singly and are 

 rolled or broken, it is probable that they have been washed out of 

 the older diluvial beds. As palaeolithic man was also the contem- 

 porary of these animals, there seems to be a broad foundation for 

 the hypothesis I have advanced, that his disappearance from Europe, 

 as well as that of the extinct mammals, was caused by the same 

 event — the rising of the great flood that overwhelmed the whole of 

 Northern Europe up to 1700 feet above the present level of the sea, 

 whilst most of the higher land was covered with ice. Palaeolithic 

 man, according to my reading of the evidence, only lived in Europe 

 in prediluvial times. 



The sands that lie above the lower diluvial clay at Taganrog are, 

 I think, the equivalents of the Middle Glacial sands and gravels of 

 Western Europe, which are largely developed in the north of Ger- 

 many and in our own country. They mark, I believe, the sudden 

 and tumultuous discharge of the first great lake by the breaking 

 away of the ice dam of the Atlantic, causing an enormous rush of 

 water, that swept away much of the diluvial clay and boulder-beds, 

 and rearranged the materials, including the implements of palaeo- 

 lithic man and the bones of the prediluvial mammals, in great 

 sheets of gravel spread out over the lower ground *. 



The outlet to the Atlantic must have been soon closed up again, 

 and the great lake reformed. The deposition of the Upper Diluvial 

 Clay of South Russia and the Upper Boulder-clay of Northern 

 Europe then commenced. The immense mass of sediment carried 

 as far as the Black Sea, and the distant transport of the northern 

 blocks in the same direction, are strong evidences that the currents 

 flowed that way. and towards the Straits of the Bosphorus. It is 

 therefore probable that the waters were ultimately lowered by the 

 excavation of a channel between the Black Sea and the Medi- 

 terranean. 



* See Quart. Journ. Geol. Soc. vol. xxxii. p. 80. There is some evidence that 

 the waters rushed across Languedoc to the westward, which probably indicates 

 that the barrier of ice that gave way was that between the Alps and the 

 Pyrenees. 



