THE MIOCENE PERIOD 819 



The Land Animals 



The earlier fauna. The early Miocene (John Day epoch 1 ) land 

 fauna of North America was very distinct from the late Miocene 

 (Loup Fork epoch). The earlier resembled the Oligocene (White 

 River) fauna in general aspect, but most of the mammalian genera 

 and nearly all the species were new and more modern. Primitive 

 carnivores were succeeded by true carnivores, chiefly of the cat and 



Fig. 549. A Miocene Mastodon, Tetrabelodon angustidens Cuvier. (Res- 

 toration by Gaudry.) 



dog families. Several branches of the perissodactyls had disappeared, 

 reducing them essentially to their three persistent lines, exemplified 

 by the horse, the tapir, and the lowland rhinoceros. The even- 

 toed branch also had developed into modern lines. Rodents were 

 abundant, including squirrels, beavers, gophers, rabbits, etc. 



The later fauna. Elephants. A notable addition to the mam- 

 malian fauna of North America in the late Miocene, was the probos- 

 cidians. Primitive proboscidians lived in Egypt at least as early 

 as the Middle Eocene, and in Europe in the early Miocene. Ele- 

 phants reached North America in the late Miocene, and South 

 America in the Pliocene. 



1 Perhaps all the John Day beds should be classed as Oligocene (p. 781). 



