262 MAN AND THE GLACIAL PERIOD. 



it bad not risen northward to a still greater relative 

 height. 



As would be expected from the climatic conditions 

 accompanying the Glacial epoch, man's companions in the 

 animal world were very different during the period when 

 the high-level river gravels of America were forming from 

 those with which he is now associated. From the remains 

 actually discovered, either in these gravels or in close prox- 

 imity to them, we infer that, while the mastodon was the 

 most frequent of the extinct quadrupeds with which man 

 then had to contend in that region, he must have been 

 familiar also with the walrus, the Greenland reindeer, the 

 caribou, the bison, the moose, and the musk ox. 



In the Glacial Terraces of Europe. 



The existence of glacial man in Europe was first de- 

 termined in connection with the high-level river gravels 

 already described in the valley of the Somme, situated in 

 Picardy in the northern part of France. Here in 1841 

 Boucher de Perthes began to discover rudely fashioned 

 stone implements in undisturbed strata of the gravel ter- 

 races, whose connection with the Glacial period we have 

 already made clear. But for nearly twenty years his dis- 

 coveries were ignored by scientific men, although he made 

 persistent efforts to get the facts before them, and pub- 

 lished a full account of them with illustrations as early as 



Fig. 77.— Section across valley of the Somme : 1. peat, twenty to thirty feet 

 thick, resting on gravel, a : 2. lower-level gravels, with elephant-bones and 

 flint implements, covered with river-loam twenty to forty feet thick ; 3, 

 npper-level gravels, with similar fossils covered with loam, in all, thirty feet 

 thick ; 4, upland-loam, five to six feet thick ; 5, Eocene-Tertiary. 



1847. Some suggested fraud on the part of the workmen ; 

 others without examination declared that the gravel must 



