DISCOVERY OF REMAINS OF PREHISTORIC MAN 71 



lithic times and discover a little what was the hfe and civiHza- 

 tion of these ancient people. While prehistoric archaeology is 

 giving us information of the civilization of these far distant ages, 

 it is to geology that we must turn for our knowledge of the 

 physical conditions which then prevailed. It is beyond the scope 

 of our present discussion to consider the cause of the Ice Age, 

 but we know that it took the place, in the Northern Hemisphere 

 at least, of the exceedingly mild and even subtropical conditions 

 of the period which preceded it. It was not an unbroken 

 period of ice and snow, but rather an epoch of oscillation between 

 severe conditions and those distinctly temperate and of much 

 equability. The periods of severe conditions, which were rather 

 times of great precipitation with moderate cold, than of remark- 

 ably low temperature, for the former seems more necessary to 

 an ice age than the latter, reached their culmination in the 

 so-called second glacial period, when all Northern Europe, 

 including the British Isles, was covered with a vast, unbroken 

 sheet of ice, and all the higher peaks and ranges sent their 

 immense glaciers far down the valleys, and spread their morainic 

 debris where are now fertile plains. 



Geikie and other glacialists recognize six periods of the severe 

 conditions, when glacial conditions more or less prevailed, with 

 their corresponding interglacial periods of considerable mild- 

 ness and equability. The third glacial period was nearly as 

 severe and the extent of its glaciers nearly as great as during 

 the time of maximum glaciation which preceded it. During 

 the fourth, the great Baltic glacier obtained vast dimensions, 

 but the last two returns to glacial conditions were very feeble, 

 and represented the dying out of the Ice Age and the commence- 

 ment of those physical conditions which we know to-day. 



Of man's presence as far back as the second-interglacial 

 period, there is not the least doubt. His tools, weapons, and 

 implements, found in deposits of that age, in the undisturbed 

 cave earths, mingled with the bones of extinct Quarternary 

 animals, and covered deep under slow-forming stalagmite, in 

 the diluvium of river valleys, and in other deposits, furnish 

 unmistakable evidence. 



