PLEISTOCENE PERIOD 197 



and the whole of Holland, escaped it ; its southern reach was 

 less in Germany: and nearly the whole of Russia seems to 

 have been free. Switzerland, however, was again entombed 

 by locally formed glaciers. 



This second glaciation, though less widespread than 

 the first, must have entailed many migrations, and some 

 extinctions of life. Where retreat was not cut off, animals, 

 that had penetrated to the north, naturally moved down 

 to lower latitudes, and elephants and hippopotamuses 

 probably migrated as far south as Africa. At the same time 

 northern species of plants spread in southerly directions, 

 following in the wake of temperate species seeking congenial 

 conditions further south. The cold must, at times, have 

 been very great, even in central Europe, for reindeer, arctic 

 foxes, and wolverines occasionally came as far south as the 

 Mediterranean. 



As the conditions in Siberia seem at this time not to have SIBERIA 

 been exceptionally severe, and as most of Russia was free 

 of the ice-sheet, some of the mammoths, woolly rhinoceroses, 

 and other descendants of Siberian emigrants in Europe 

 may have returned to the lands of their forefathers. It 

 is likely, however, that most of them remained in Europe, 

 as in many parts they must have found the climate quite 

 tolerable and food sufficient. And if they remained in 

 force, so also would carnivores. 



Long was the greater part of northern Europe under EUROPB 

 the icy mantle ; and, save for the sweep of air currents, 

 the silentness of vast expanses of country remained unbroken. 



But all things, however unpleasant, come to an end. 

 Upheaved lands in course of time subsided ; the accumulation 

 of snow on the great gathering grounds grew less and less ; 

 the vast ice-sheet was again in retreat, and great migrations 

 of life ensued. This retreat of the ice may be spoken of as 

 final, for the earth has not since experienced a glacial visita- 

 tion. 



There is no evidence to show if the descendants of the 

 inter-glacial hunters remained in Europe during the second 

 great glaciation. But as soon as the ice commenced to retire 

 men were roving about the continent. 



