122 OKIGIN OF LIFE IN AMEKICA 



dence for the assumption that the general movement of the 

 fauna has been from the Old World to the New. Finally, 

 in the Pliocene beds of North America, we perceive clearly 

 that an invasion of South American animals has taken 

 place.* 



* Osborn, H. F., " Cenozoic Mammal Horizons," pp. 42 82. 



