THE MIOCENE OF EUROPE, ASIA, AND NORTH AMERICA 265 



view is that tliis fauna is an outlier of that which prevailed both in Asia 

 and in Africa in Upper Miocene times. The various opinions on the im- 

 portant point of the origin of this Pontian fauna will be cited later. 



With the advent of this new plains fauna, but especially with the ad- 

 vent of these new conditions of life in southern Europe, it is not surprising 

 to find a temporary retreat of the forest fauna. The old Miocene browsing 



Fiu. 132. — Distribution of the ' Hipparion Fauna' in the eastern hemisphere. 



fauna is partly dying out, partly retreating to the north, partly returning 

 to the forests, hillsides, and swamps of Asia and Africa. 



Physiographic conditions. — De Lapparent ^ gives a clear account of 

 the physiographic changes. In the Upper Miocene, or Pontian, the general 

 recession of the sea, begun in the Middle Miocene or Vindobonian, con- 

 tinues until the Mediterranean Sea has almost wholly dried up, or become 

 reduced to a number of brackish lakes. As a result Europe is l^roadly con- 

 nected with Asia and Africa; the waters of the great l^asins of eastern 

 Europe grow gradually less saline, and are replaced by the Caspian Sea 



' Dc Lapparent, A., Traite de Geologic, 1906, p. 1622. 



