THE GLACIAL PERIOD. 241 



channels, which would have no permanency, while that under- 

 neath the ice would tend to collect into larger currents which 

 might keep an open course for themselves for long periods of 

 time. Thus the water pouring off the surface of the ice would 

 descend upon Germany in innumerable cascades, but would sel- 

 dom or never discharge at any one point such enormous floods 

 of water as those carried north by rivers coming from regions 

 of alpine snows and glaciers. Moreover, we must remember 

 that it would be comparatively pure water — it would hold in 

 suspension an infinitely less amount of sediment than such rivers 

 as the Ehine or the Danube. But the case would be very differ- 

 ent with the water flowing out from under the ice-sheet in Eussia. 

 A glance at the map of Europe (Plate D) will show that a very 

 large section of the extensive area which is drained by the Dnieper, 

 the Don, the Yolga, and their numerous affluents, was covered 

 by the mer de glace. The ice-sheet flowed out of the Gulf of 

 Finland, ascended the long slopes that drain towards the Baltic, 

 crossed the water-parting, and thereafter pressed forward for a 

 distance of not less than 300 miles in the direction of the Black 

 Sea. South of the water-parting referred to, the sub -glacial 

 drainage would therefore be in the same general direction as 

 the present rivers. Consequently we should expect to find in 

 Southern Eussia abundant evidence of vast inundations — inun- 

 dations on a much grander scale than any that could possibly 

 have taken place in Middle and Western Europe. Large rivers 

 and innumerable torrents, laden with glacial mud, would issue 

 from the terminal front of the ice-sheet, and literally deluge the 

 gently - undulating ground and low flats and plateaux which 

 extend south to the Black Sea and the Caspian. In winter the 

 waters would be greatly reduced in volume, while the rivers to 

 the south of the ice -sheet would doubtless be frozen over. 

 Snow might then gather over extensive areas in what are now 

 the Steppes, and here and there be swept by violent winds into 

 great heaps and wreaths, just as is the case at present in those 

 regions and the tundras. When spring returned such wide 

 sheets and hummocky masses of snow would begin to melt 



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