HOLMES DISTRIBUTION OF THE HUMAN RACE. 27 



near Escholtz Bay on the American coast, and they are traced 

 along the Andean backbone of the continent into South America ; 

 but they extended no further eastward in North America, down 

 to the end of the Pliocene period, than to the western shores of 

 that extensive fresh-water Lake of the Miocene and Pliocene 

 periods. But after that barrier had been cut oft' by a further ele- 

 vation of the land, and in Postpliocene times, the Mastodon, with 

 Man in company, appears to the eastward of it, and not before. 

 It is in these same Postpliocene times only that the Megatherium, 

 Megalonyx, Peccary, and perhaps other animals of South Ameri- 

 can types, are found within the southern United States, when 

 both the ancient lake and the ocean barrier across the isthmus 

 had ceased to obstruct their progress northward. Prof. Marsh 

 has recently expressed the opinion that these gigantic Edentates 

 had their first evolution in northwest America, and that they 

 reached South America after the passage was opened over the 

 isthmus in the Tertiary period, though their remains are more 

 abundant in South America. This theory of their origin in re- 

 spect of type would not, perhaps, be inconsistent with the suppo- 

 sition of a return migration of these larger species from South 

 America into the United States in the later Postpliocene times. 

 Prof. Marsh concludes that the Horse, Rhinoceros, Tapir, Camel, 

 Pig, and Deer, were natives of the northwest territories of Amer- 

 ica, and that they passed into Asia over that same bridge of Behr- 

 ing's Straits ; and that the Bears and Antelopes passed from Asia 

 into America by the same way ; but that the Sheep, Goat, and 

 Giraffe, were stopped by the disappearance of the bridge before 

 they could get over. The Camels (llama, vicuna, &c.), which 

 appear to have originated in western North America, must 

 have reached South America, in like manner as the Mastodons, 

 by the passage over the isthmus, after the barrier was removed ; 

 and they are to be regarded as survivals of the type in that area. 

 The Pliocene men could easily reach South America by the same 

 route. And, in like manner as they reached the eastern por- 

 tion of North America, they would readily extend to Brazil and 

 Guiana when those areas ceased to be islands separated by wide 

 ocean barriers from the Andean ridge. In later times, they would 

 easily reach the West India islands from both North and South 

 America. Human remains have been found in Brazilian caves, 



