1869.] DAWKINS BRITISH POSTGLACIAL MAMMALS. 215 



action, show that the winter at least was such as may now be felt 

 in the woodland region of northern Siberia. The presence of the 

 arctic group of mammals, the Reindeer, Musk-sheep, and the like, 

 implies that the cKmate under which they lived was severe. But, 

 on the other hand, the presence of the Hippopotamus major in 29 

 localities, an animal that, so far as we can judge by the habits of 

 the living species, could not have endured the low temperature now 

 necessary for the wellbeing of the Musk-sheep or Reindeer, involves 

 the necessity of supposing the climate to have been temperate or 

 comparatively warm. M. Lartet, in his last Essay on the " Car- 

 nassiers et Ehinoceres fossiles du Midi de la France '* *, explains the 

 difficulty in the following way : — First of all, he assumes that the 

 arctic herbivores dwelt in France throughout the year side by side 

 with the Hippopotamus ; and then he infers that the Postglacial cK- 

 mate was more equable and insular than that of France at the pre- 

 sent day. But it is established beyond all cavil that during the 

 time the Postglacial fauna occupied Britain our island formed an 

 integral portion of the continent of Europe — a fact that would at 

 once demolish the idea of the existence of an insular cKmate during 

 that epoch. The Hippopotamus most probably was, as Sir Charles 

 Lyell suggests, a summer visitant only, and retired southwards in 

 the winter to a more genial clime. I know of no other hypothesis 

 that satisfies all the conditions of the problem. 



From that time down to the present day the climate has gra- 

 dually been modified. As Britain became insular the climate grew 

 more equable, until in the Prehistoric epoch the sole survivors of the 

 northern invaders were the Elk and Reindeer f, the latter of which 

 grew more and more scarce until at last it became extinct in the 

 mountains of Caithness towards the end of the twelfth century. 



Discussion. 



The President suggested that a fourth period might be added to 

 the three adopted by the author, viz. the Glacial period, during 

 which it would appear from the paper that some, if not all, of the 

 *' postglacial" animals may have lived in Britain. 



Mr. Busk remarked that some of the genera referred to both the 

 Postglacial and Preglacial periods (such, for instance, as the Hyaena, 

 Lion, and Hippopotamus) were of southern, and not, like many of 

 the others, of northern and eastern origin. The Lynx also might 

 not improbably be of African descent. It was abundant in the bone- 

 breccia of Gibraltar, as was also the Cervus elaphus and C. dama. 

 JSlephas antiquus and Rhinoceros might also be regarded as southern 

 forms; and it was worth consideration whether these portions of 

 the fauna might not be connected with the time when Southern 

 Europe was joined on to J^orthern Africa. 



Mr. Tate stated that at Carrickfergus there was a forest-bed 

 underlying glacial drift, from which possibly the elephant-remains 

 found there had been derived. 



* Ann. des. Sc. Nat. tome viii. p. 157 et seq. 



t " On the Range of the Reindeer," Pop. Science Review, 1867. 



