CLOSE OP POST-PLIOCENE — ADVENT OF MAN. 303 



sent day, the puma, or American lion, comes up to 

 the same latitudes with the caribou, or reindeer, and 

 moose; and in Asia, the tiger extends its migrations 

 into the abodes of boreal animals in the plains of 

 Siberia. Even in Europe, within the historic period, 

 the reindeer inhabited the forests of Germany; and 

 the lion extended its range nearly as far northward. 

 The explanation lies in the co-existence of a densely 

 wooded country with a temperate climate ; the forests 

 affording to southern animals shelter from the cold of 

 winter; and equally to the northern animals protec- 

 tion from the heat of summer. Hence our wonder 

 at this association of animals of diverse habitudes as 

 to climate, is merely a prejudice arising from the 

 present exceptional condition of Europe. Still it is 

 possible that changes unfavourable to some of these 

 animals, were in progress before the arrival of man, 

 with his clearings and forest fires and other dis- 

 turbing agencies. Even in America, the megalonyx, 

 or gigantic sloth, the mammoth, the mastodon, the fossil 

 horse, and many other creatures, disappeared before 

 the Modern period ; and on both continents the great 

 Post-glacial subsidence or deluge may have swept 

 away some of the species. Such a supposition seems 

 necessary to account for the phenomena of the gravel 

 and cave deposits of England, and Cope has recently 

 suggested it in explanation of similar storehouses of 

 fossil animals in America.* 



* Proceedings of the American Philosophical Society, April, 

 1871. 



