36 THE MIGRATION OF BRITISH BIRDS 



the last glacial period, but as an eloquent and uncon- 

 trovertible testimony to their extermination through 

 adverse conditions of life, due not only to severities of 

 climate but to narrower areas of distribution. As Pro- 

 fessor Geikie himself remarks : " We have seen that a 

 number of characteristic Pleistocene animals had made 

 their appearance in England at the close of the Pliocene 

 Period, or shortly before the advent of the earliest 

 recognized glacial epoch of Pleistocene times. They 

 were associated with several Pliocene forms, such as 

 Hippopotaimis ainpJiibins, ElepJias mei-idionalis, i\IacJiai- 

 rodus latidens. Rhinoceros ctniscus, R. mcgarliinus, Ursus 

 arvernensis, Cervus dicranios, and C. poIig?iaa/s. Of 

 these, one, the hippopotamus, is still living, while others 

 do not appear to have survived in North-western Europe 

 the first glacial epoch. The southern elephant and the 

 megarhine rhinoceros, however, struggled on into inter- 

 glacial times, when the former occupied the \alle}- of the 

 Rhone, Central France, and Northern Italy, and the 

 latter ranged from Southern Europe into England. The 

 sabre-toothed tiger also would seem to have persisted 

 well on into the Pleistocene Period. Of the other 

 animals that come into view for the first time in the 

 pre-glacial deposits of Cromer, many appear and re- 

 appear in successive inter-glacial deposits ; but wc note 

 as we advance toward the later stages of the Pleistocene 

 that some of them become rare, while others vanish 

 altogether. The recurrent glacial epochs seem to have 

 told severely upon many of the herbivorous animals. 

 The only two pachyderms that have survived are the 

 hippopotamus, already mentioned, and the African 

 elephant. During each successive glacial epoch those 



