PRELIMINARY CONSIDERATIONS. 8 1 



moutonnfos very similar to those produced by the 

 glaciers of Switzerland, it must have been traversed 

 by "inland ice" flowing from Scandinavia and the 

 Baltic southward. The boulder clay of Germany is 

 supposed to have accumulated underneath this 

 vast " mer de glace" as he calls it. There is 

 no question here of a simple local development 

 of glaciers, such as could have existed under a 

 mild and moist climate; practically all the plants 

 and animals would have been annihilated in northern 

 Europe under such conditions, as there were no areas 

 free from ice. A more vivid idea of the state of 

 Europe during the epoch of maximum glaciation 

 will be obtained by looking at Professor Geikie's 

 map (p. 437). The whole of Scandinavia, Iceland, 

 Scotland, Ireland, and Switzerland is there repre- 

 sented as having been completely enveloped in ice, 

 and also the greater part of Russia, Germany, and 

 England. In speaking of Scandinavia (p. 424) he 

 remarks that "the whole country has been moulded 

 and rubbed and polished by one immense sheet 

 of ice, which in its deeper portions could hardly 

 have been less than 5000 feet or even 6000 

 feet thick." The greater portion of the area in- 

 dicated as having been underneath a sheet of ice is 

 thickly covered with superficial accumulations of 

 gravel, sand, and clay. The latter is generally 

 spoken of as " boulder clay," and, with the associated 

 sand and gravel, it may be observed equally well in 



Russia or Germany, in England or Ireland. As a 



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