7O HISTORY OF THE EUROPEAN FAUNA. 



matter whether there be I or 20 degrees of cold. 

 Winters with a few degrees of frost will be just as 

 favourable for the growth of glaciers as winters with 

 the most severe cold. 



Let us now see what the fauna and flora, as far 

 as we know it, tell us of the climate of the Glacial 

 period. At the very outset of our inquiry we are 

 confronted with one very serious difficulty in the 

 problem, and that is the supposed occurrence of inter- 

 glacial mild phases alternating with colder ones during 

 the Ice Age. At first, when traces of a temperate flora 

 and fauna were discovered intercalated between two 

 layers of boulder clay, their presence was explained 

 by the supposition of a mild inter-glacial period. 

 The famous Forest-bed on the east coast of England 

 was also pronounced to be an inter-glacial deposit, 

 though not coming precisely under this definition. 

 In a few places one such bed was found, in some two 

 or more, and in others none at all. Professor James 

 Geikie discovered the evidences of no less than five 

 of such inter-glacial epochs (p. 612) in Europe. 

 Lest a reader of that author's remarkable work on 

 the Ice Age might carry with him the idea that his 

 hypotheses had met with general acceptance, a few 

 quotations from almost equally high authorities on 

 glacial matters will be useful. "That the glaciers," 

 remarks Professor Bonney (p. 245), " were liable to 

 important oscillations seems to be proved, but whether 

 the evidence suffices to establish inter-glacial epochs, 

 in the usual sense of the words, is more doubtful. 



