OSBORN. REVIEW OF THE PLEISTOCENE 



253 



the deposits of this glacial advance are known as the old "Diluvium" or 

 the "Oldest Drift;" the advance is termed the Scanian by Geikie. In 

 the Alpine Region it has been termed the Giinz by Penck and Bruckner, 

 and the drift deposits have a general thickness of 30m. At about the 

 same time a great ice cap was formed in British North America west of 

 Hudson Bay from a centre known as Keewatin which sent its ice sheets 

 into Iowa and Nebraska. The resulting Nebraskan deposits, consisting 

 largely of compact boulder clays, are often thickly set with woody ma- 



west longitude 80 from Oreenwich 



Fig. S. — Chief centers of North American glaciation 

 Keewatin. Labradorean, Cordilleran. After Leverett. 



terial gathered from forests of spruce and other coniferous species that 

 indicate the development of a cool temperate flora in advance of the 

 glaciation. 35 



It does not appear that a glacial cap of any considerable extent was 

 formed in Great Britain ; but Geikie 36 shows that along the British coast 



35 The above correlation is presented chiefly on the authority of Penck and Leverett 

 (op. cit., 1910). 

 26 Geikie, James : The Great Ice Age. 2nd Ed. London, 1877. 



