PROPOSED EXPI^ORATIONS AND INVESTIGATIONS 25 1 



has spent much time in the attempt to follow out this course of 

 investigation, but beyond the discovery of much scattered evidence 

 no result has been possible, owing to the absence of material. He 

 has been able, however, to construct a preliminary map of the life 

 zones of Europe, and his success, with the very limited data at his 

 disposal, points toward a speedy and logical settlement of the ques- 

 tion as a certain result of properly conducted explorations. 



3. Former Glaciation and Its Bearing on the Present Distributio7i of 

 Life. — It is scarcel}' necessary to allude to the close connection 

 between the more directly zoological questions and those of Post- 

 Tertiary paleontology and geology, but we may call attention to 

 the fact that recently attempts have been made, on biological 

 grounds, to belittle the extent and intensity of the glacial phe- 

 nomena in Europe during the period known as the Ice Age. It 

 has been argued, with considerable plausibility, that the conditions 

 in Europe at that time were such that a universal glaciation must 

 have been an impossibility, and that, so far from being colder, the 

 climate of Europe was then milder than at present. In our opin- 

 ion, such theories have no actual foundations, and we believe that 

 it is only defective knowledge of the minute details of the fauna and 

 flora of the entire northern world that is responsible for the fact 

 that they can be propounded and defended, a view publicly expressed 

 not long ago by one of the present writers. Nevertheless, it can 

 not be denied that with the present status of our knowledge the 

 discussion might go on indefinitely. A better knowledge of the 

 life zones of the Old World would probably also greatly promote the 

 correct understanding of the biological side, at least, of the inter- 

 glacial question. 



If the climate of Europe in the glacial period is the source of 

 much contention between widely diverging views, that of Siberia 

 and of the Asiatic Pacific coast is still more in doubt. While 

 nobody may be found to advocate a glaciation equaling in extent, 

 intensity, and duration that of Europe or North America, there is 

 no lack of authorities who maintain that the climate must have 

 been quite severe and that glaciers were not absent. On the other 

 hand, an author has within the last two years defended the propo- 

 sition that the climate of that region did not differ materially from 

 that of today. 



4. Manner of Expaiision of haunas. — It has been supposed that a 

 large proportion of the present fauna of Europe on the one hand 



