234 HISTORY OF THE EUROPEAN FAUNA. 



Epoch of the great Ice- Age. The fact that no 

 boulder-clay underlies the Forest-Bed seems rather 

 a strong argument against the view of its being an 

 inter-glacial deposit. It lies directly on what is 

 known as the Newer Pliocene Crags. If the Forest- 

 Bed is included in the pleistocene series, as I sug- 

 gested it should, the crags, or a portion of them, 

 would therefore be equivalent as regards time of 

 deposition to the lower continental boulder-clay. 

 And again, if the lower continental boulder-clay is 

 contemporaneous with the Newer Crags, the latter 

 should also be classed with the pleistocene strata. I 

 can scarcely hope that geologists will be ready to 

 admit such a sweeping change of nomenclature 

 without a protest. I venture, therefore, to explain 

 more fully my reasons for adhering to these un- 

 orthodox views. 



Let us look once more at the map which I con- 

 structed (Fig. 12, p. 156) to elucidate the migration 

 of the Arctic terrestrial species to the British Islands. 

 It will be noticed that one continuous ocean extends 

 from the east coast of England across Holland, 

 Northern Germany, and Russia to the White Sea. 

 At the same time Greenland and Northern Scandi- 

 navia, Scotland and Southern Scandinavia, are united 

 by a narrow strip of land, and so are England and 

 France. The waters of the Atlantic and this North 

 European Sea do not therefore intermingle at any 

 point, the two seas being absolutely independent of 

 one another. 



