THE PLIOCENE OF EUROPE, ASIA, AND NORTH AMERICA 361 



Plains, extending westward to the Rocky Mountains of New Mexico, and 

 spreading eastward over a much greater territory than they now occupy. 

 All the formations succeeding the ' Panhandle ' or of more recent date are 



I'loisUK^'iieiKeccii 

 i fj.i-.itpJi 



Plioteiic t libnco) 



Mioceiu'(L..uf U.rlO 



Exploinli(^ns of tlie 

 American Museum 

 »9^)-1301,under 

 J.W. Grdley. 



Fig. 1G6. — Map of a section of uorthurn Texas showing location of important fossil uianiinal 

 finds and geologic horizons. After Gidley, Amer. Mus. Exped., 1902. 



represented by comparatively small areas of fluviatile, flood plain or seolian 

 origin. 



The earliest of these more restricted formations are known as the ' Claren- 

 don,' and are of Upper Miocene or Lower Pliocene age, containing such 

 characteristic forms as Procamelus, Protohippus, Pliohippus, Hipparion, 

 and Trilophodon. The main body of the Clarendon beds consists for the 

 most part of cross-bedded sands and sandstones, intermixing more or less 



