ciiAr.vii.] BISONS IN SUMMER REINDEER IN WINTER. 191 



Bisons in District in Summer, Reindeer in Winter. 



We can readily picture to ourselves, by the aid of 

 these two narratives, the vast migratory bodies of bison 

 and reindeer, a sea of tossing manes and horns, or a 

 moving forest of antlers, passing upwards by the great 

 gaping chasm, overhung by the Peak Castle, to the 

 heights dividing the tributaries of the river Trent from 

 those of the Dee and the Mersey, followed by the wild 

 beasts as in North America and Northern Asia. The 

 bison and reindeer, however, now are not known to 

 inhabit the same country at the same time, and there- 

 fore we cannot suppose that this was the case in 

 Britain in the Pleistocene age. The difficulty may be 

 explained by the supposition that they occupied the 

 district at different seasons, which, as we have already 

 seen, were more sharply contrasted than they are at the 

 present time. An examination of their bones and teeth 

 proves that the bisons were here with calves not more 

 than three or four months old, that is to say, within 

 three or four months of calving time in May, in other 

 words, in the summer and the autumn. The remains of 

 the young reindeer, on the other hand, are very scarce, 

 and only one milk-molar, the last in the series, possesses 

 imperfect fangs ; from which it may be concluded that 

 they were not in the district in the summer and autumn 

 their calving time, according to Sir John Richardson, 1 

 also being May. They were, therefore, here in the winter 

 time, and perhaps in the early spring. This undesigned 

 piece of evidence is a strong confirmation of the truth 

 of the views held by Sir Charles Lyell and myself that 

 the association of animals, not now found together in 

 Pleistocene deposits, is due to seasonal migrations. 



1 Fauna Boreali- Americana. 



