ScHARFF — On the Origin of the European Fauna. 463 



Europe from Greece, and migrated along the Mediterranean coast to 

 "N'orthem AMca at a time when a land-bridge still existed between 

 it and Southern Italy, and then recrossed again to Spain, where at 

 last they turned north to appear in Western Eui'ope, without having 

 crossed the central parts of the continent. Such, however, could not 

 possibly have been the course of migration of the Siberian Mammals, 

 since they are not found in Southern Europe or in i!^orth Africa. 

 Hence one of the two alternatives must be accepted, either some 

 radical mistake has been made in the previous arguments, or the 

 Forest-bed is an Interglacial deposit, and contemporaneous with the 

 " Loess " formation in which the Siberian animals have been discovered 

 in J^orthern Gennany. I believe in the latter hypothesis. If this 

 view should be correct, the whole of the British Pliocene strata or a 

 portion of them, must be of the same age as the lower continental 

 boulder-clay. The marine fauna which made its way west from the 

 Arctic Ocean across the IS^orth Russian plains, and reappeared again 

 on the Baltic coasts just before the deposition of the boulder-clay, 

 must have entered the German Ocean and left its traces behind in 

 the strata which, formed on the east coast of England. And this is 

 precisely what occurred. "In the oldest member of the Pliocene 

 system," remarks Prof. J. Geikie (35«, p. 329), "in the Coralline 

 Crag, the general facies of the fauna clearly indicates a wann, tempe- 

 rate climate, for all the living species are southern forms. In the 

 Peg Crag, however, northern forms begin to appear, and increase in 

 numbers as we pass upwards to the higher members, while at the same 

 time the extinct and southern forms gradually die out." If the view 

 that the Eorest-bed represents an Interglacial deposit is correct, as 

 indeed has already been suggested by Professor Geikie (35 a, p. 479), 

 the whole of the newer Bi'itish Pliocene is synchronous with the 

 lower continental boulder-clay. I will not dwell on this subject any 

 longer, as it will be more fully dealt with later on, but in the succeed- 

 ing pages a good many facts in support of this theory will be brought 

 forward. 



Let us once more return to Eastern Europe. It will be objected to 

 that, though there may be evidence of a marine trangression from 

 the Arctic Ocean before the lower boulder-clay was laid down, there 

 are such cogent reasons for believing in the terrestrial origin of the 

 latter, that the marine connexion between the Aralo-Caspian and the 

 White Sea which formed a barrier to the passage of the Siberian fauna 

 could no longer have existed. Foremost among the objections to the 

 theory of the marine origin of this boulder-clay is the absence of 



