ENVIRONMENT OF THE TITANOTHERES 



Mammalian life of the WashaMe Basin 



89 



ZONES 13 AND 14: METARHINUS ZONE AND EOBASHEUS-DOIICHORHmUS 

 ZONE 



[Uinta B 1 and Washakie B 1; Uinta B 8] 



The great life division known as Washalde B, 380 

 feet in thickness, contains a new and dominant fauna, 

 which is not represented at all in Bridger D or Wash- 

 akie A. It is significant that this unit is divided into 

 two zones by its fauna, exactly as Uinta B is divided 

 into two zones, the Eoiasileus-DoIichorMnus zone 

 (Washakie B 2 = Uinta B 2), and the Metarhinus 

 zone (Washakie B 1 = Uinta B 1 = (in part) Bartonian 

 of Europe). Certain of the older mammalian families 

 and genera (as Uintatherium) begin to disappear and 

 101959— 29— VOL 1 S 



new generic and specific forms replace them. Con- 

 spicuous among these is the amblypod Eobasileus, 

 first described from this region by Cope, which re- 

 places Uintatherium. A full list of this fauna is given 

 above. Among the distinctive forms are the fol- 

 lowing : 



Eobasileus cornutus Cope, 



type; 

 DoHchorhinus hyognathus 



Scott and Osborn, type. 

 Uintatherium speirianum 



Osborn, type. 

 Triplopus cubitalis Cope, type. 



Eomoropus amarorum Cope, 



type. 

 Amynodon antiquus Scott and 



Osborn. 

 Achaenodon insolens Cope. 

 Metarhinus earlei Osborn, 



type. 



