PRELIMINARY CONSIDERATIONS. 53 



from the cast was the late Mr. Bogdanov. The 

 Arctic species, of which remains have been discovered 

 in the Pyrenees namely, the Reindeer, Arctic Hare, 

 Willow Grouse, etc., he thought had nothing to do 

 with those which invaded Europe from Siberia during 

 the Glacial period. He maintained that the former 

 had quite a distinct origin, and came from Scandi- 

 navia (p. 26). 



As I shall deal with this problem more fully in a 

 subsequent chapter, I need only mention that I fully 

 agree with the view expressed by Mr. Bogdanov that 

 two distinct migrations of northern species to Central 

 Europe can be traced. 



No one, I think, has done more in fostering a care- 

 ful study of the migrations of animals than our 

 distinguished geologist Professor Boyd Dawkins. He 

 did not follow Bogdanov in distinguishing two Arctic 

 migrations; however, he did more in constructing a 

 very ingenious chart (a, p. ill) representing the geo- 

 graphy of Europe during the last and most recent 

 geological epoch the Pleistocene and indicating on 

 it the probable extent, during that time, of an eastern 

 and a southern migration of mammals. The map is 

 very instructive, and is the first ever published giving 

 a clear idea of a southern and an eastern migration 

 to Europe. He believed that the migration of the 

 southern mammals northward, took place conjunctly 

 with the westward movement of the eastern species. 

 Having once reached Europe, the southern species 

 are supposed to have passed northward in summer 



