1 88 HISTORY OF THE EUROPEAN FAUNA. 



Arctic Hare is equally instructive. It must have been a native 

 of Europe since early glacial or pre-glacial times before the 

 common English Hare had made its appearance in Central 

 Europe. Along with other Arctic forms, it entered Northern 

 Europe directly from the Arctic Regions, by means of the former 

 land-connection which joined, as I remarked, Lapland with 

 Spitsbergen, Greenland, and North America. There need not 

 have been a post-glacial connection between Europe and 

 Greenland ; the present flora of that country may have survived 

 the Glacial period in the Arctic Regions, as has been main- 

 tained by some botanists and other authorities. Professor 

 Forbes argued from the occurrence of the same species of 

 shore mollusca on the coast of Finmark and Greenland that 

 these two countries were not long ago joined, so that a slow 

 migration from west to east along an ancient coast-line could 

 have taken place. That such a migration actually occurred is 

 further made probable, judging from the presence of American 

 mollusca in the Crag deposits on the east coast of England. 

 These came into the North Sea in the first place direct from the 

 Arctic Ocean at a time when the two oceans freely communi- 

 cated with one another across the lowlands of Northern Russia, 

 Northern Germany, and Holland. Arctic shells are also found 

 below the boulder-clay on the Baltic coast, and a free com- 

 munication such as indicated is generally held to have taken 

 place at no very distant date. The so-called "relict species" 

 marine animals left in freshwater lakes in districts formerly 

 covered by this sea lend some support to this view. But the 

 view that the continental boulder-clay is a marine deposit is not 

 now held except by a few, though I here bring it forward again, 

 as it seems to me to fit in so much better with the known facts 

 of distribution. The sea just referred to probably existed 

 throughout the greater part of the Glacial period; and icebergs, 

 which originated from the Scandinavian glaciers, would have 

 brought detritus and boulders to the lowlands. Scandinavia 

 was then connected with Scotland, and England with France. 



