ARCTIC INTERGLACIAL PERIODS. 191 



glacial period. When the cold came on, and the 

 vegetation on which it subsisted began to disappear, 

 it would move southwards, and would continue its 

 march as the cold and severity of the winters increased. 

 During the continuance of the ten or twelve thousand 

 years of Arctic conditions it would find in Southern 

 Europe and elsewhere places where it could exist. At 

 the end of the cold period, and when the climate again 

 began to grow mild and equable, it would retrace its 

 steps northwards. There is, however, little doubt that 

 during the severity of a glacial period, and when 

 necessarily confined to a more limited area, its numbers 

 would be greatly diminished. There is every reason 

 for believino- that the mammoth outlived all that 

 succession of cold and warm periods known as the 

 Glacial Epoch proper, and did not finally disappear till 

 recent postglacial times. 



It was probably about the commencement of a cold 

 period, and before the mammoth had retreated from 

 Northern Siberia, that those individuals perished 

 whose carcases have been found frozen in the cliffs. 

 The way in which they probably perished and became 

 imbedded in the frozen mud and ice has, I think, been 

 ingeniously shown by Dr. Rae. His views on the 

 subject are as follows : — 



" The mammoths drowned would float down the rivers, and 

 would probably get aground in three or four feet of water. 

 As soon as the winter set in, they would be frozen up in this 

 position. The ice in so high a latitude as 70° or 75° north 

 would acquire a thickness of five or six feet at least, so that 

 it would freeze to the bottom on the shallows where the 

 mammoths were anchored. In the spring, on the breaking- 

 up of the ice, this ice being solidly frozen to the muddy 

 bottom would not rise to the surface, hut remain fixed, with 

 its contained animal remains, and the flooded stream would 



