434 THE AGE OF MAMMALS 



III. PLEISTOCENE LIFE OF NORTH AMERICA 



The early and mid-Pleistocene life of North America is the grandest and 

 most varied assemblage of the entire Csenozoic Period on our continent. 

 It lacks the rhinoceroses of Europe, but possesses the mastodons, in addition 

 to an array of elephants more varied and quite as majestic as those of the 

 Old World. Great herds of large llamas and camels are interspersed A\dth 

 enormous troops of horses. Tapirs roam through the forests. True cattle 

 (Bos) are not present, but imposing and varied species of bison are widely 

 distributed. An element entirely lacking in Europe is that of the varied 

 types of giant sloths, which were scattered all over the country, as well as the 

 great armored glyptodonts in the South. Preying upon these animals are 

 not only saber-tooth cats, but true cats, rivaling the modern lion and tiger 

 in size. 



A fact of great importance is that we now witness for the first time 

 the life of the entire United States, of the Plains and Mountain regions of 

 the West, of the Pacific slope, of the vast and hitherto unknown forested 

 stretches of the East, of the sandy savannahs of the South, as well as of 

 portions of British Columbia and Alaska. This more extended range of 

 knowledge enhances both the interest of the subject and its difficulties. 

 When we attempt to correlate the age of faunas east and west of the Sierras 

 and Rocky Mountains, we must consider the influences of these great 

 barriers and of the Pacific Ocean. (See Fig. 194.) 



It is true that most of the testimony is of a fragmentary character, but 

 its geographic range and zoologic diversity are compensating features. The 

 fossil mammals of the East were the first to draw the attention and excite 

 the wonder of the pioneers of American palaeontology, of De Kay, Jefferson, 

 Harlan, Couper, and Holmes. It was natural that the discoveries in the 

 Tertiary of the West from the middle of the nineteenth century onward 

 should have diverted attention from the less showy but no less important 

 Quaternary fauna. Leidy, Marsh, and Cope gave it little attention. Quite 

 recently, however, interest has begun to revive, and the studies of Mercer, 

 J. C. Merriam, Sinclair, Furlong, Lucas, Brown, and others are bringing 

 the Quaternary again into its deserved prominence. A thorough-going re- 

 vision of these mammals and of their environment is still required; for it 

 must be acknowledged that the present review is based upon very incom- 

 plete zoologic and geologic data. 



