QUATERNARY 



667 



Fig. 576. — Pleistocene tar pool near Los Angeles, California, with entrapped ani- 

 mals. The elephant and wolves were caught, and the saber-toothed tiger is about 

 to suffer the same fate. (After Prof. W. D. Scott, History of Land Mammals.) 



still filled with the half-chewed remnants of its food which consisted of 

 twigs of spruce, fir, and other trees. 



REFERENCES FOR THE LIFE OF THE PLEISTOCENE 



Geikie, J., — Antiquity of Man in Europe. 



Matthew, W. D., — The Asphalt Group of Fossil Skeletons: Am. Museum Jour., 



Vol. 13, pp. 291-297. 

 Osborn, H. F., — Age of Mammals, pp. 467-480, 487, 498. 

 Scott, W. B., — A History of Land Mammals in the Western Hemisphere, pp. 29-49. 



Vegetation. — The vegetation of the Pleistocene is a continuation 

 of that of the Tertiary, and aside from the extinction of a few species 

 little change is noticed. Some minor effects of glaciation on vege- 

 tation are, however, interesting. It is found, for example, that the 

 number of genera of trees in Europe (33 genera) is much smaller than 

 in eastern North America {66 genera). A study of a glacial map of 

 Europe and North America suggests an explanation. It is seen that 

 at the time of maximum glaciation in Europe the vegetation was con- 

 fined between the front of the great ice sheet on the north and the 



