PLEISTOCENE PERIOD 191 



ceptionally severe conditions. Thick-haired mammoth- 

 elephants with big curling tusks (E. primigenius), and rhi- 

 noceroses in woolly apparel (R. tichorhinus), that had long 

 gathered sustenance in those frosty regions from spruces 

 and junipers, were now seeking new feeding grounds. Many 

 of the mammoths, no doubt, were moving to less inhospitable 

 parts of Asia ; some were seeking European pastures ; others 

 were migrating to North America on the land-way then 

 existing in the Behring Strait region. Some of the woolly 

 rhinoceroses wandered into Europe among them a few 

 curious forms with a huge horn rising unicorn-like from 

 the forehead (Elasmotherium). So far as is known no rhi- 

 noceroses faced the terrible north-eastern journey, under- 

 taken by some of the mammoths. 



Nor were the central and southern parts of Asia wholly 

 exempt from great ice visitations. The Himalayas certainly 

 formed a centre for ice dispersal ; and numerous glaciers 

 rolled to the south and west from the snow-hidden mountains. 



From elevated lands of Labrador in the east, from central NORTH 

 snow-fields amassed in Keewatin, and from half-buried AMERICA 

 " Rockies " away in the west, glaciers were bringing vast 

 stretches of North America much into the condition of that 

 of northern Europe. 



The increase of the cold had been gradual ; and many 

 animals by timely retreat had doubtless escaped suffering 

 and death. The destruction of life, however, in North 

 America must have been very great, as well as in Europe 

 and Asia. 



In the long course of years the glaciers, increasing in EUROPE 

 volume, rose high up the mountain-sides that hemmed them 

 in. Finally the heights were overridden ; and numerous 

 glaciers, uniting across the topmost ridges, formed vast 

 sheets of continuous ice. An ice-sheet seems to have ex- 

 tended practically over the whole of northern Europe ; 

 for evidence shows that Ireland, Wales, Scotland, England 

 (as far as the Thames Valley), the North Sea, Norway, 

 Sweden, Denmark, Holland, Germany (as far south as 

 Dresden), the greater part of Russia, and the whole of the 

 Baltic Sea were covered with ice and snow. Switzerland 



