OLIGOCENE OF EUROPE, NORTH AFRICA, AND NORTH AMERICA 233 



^;=^-v^^ Columbia River lava 



^^ {basalt flow. 2000 feet) 



Forest on top of ashes 



O 



Camelidae 



Fromerycochcer^js zone 



(lowest lei^el) 



\ ',->A-) ;~N R Ti y dnUcTTo w 



250- 

 300 



Anchitherlum 



M or opus 



Entelodon 



Paratylopus 



Eporeodon 



HypertraguluS 



Miohlppus 

 Protapirus 

 Mar opus 



DiceratloeriuTn Eporeodon 

 zone Agriochdhrus 



(fossils, numerous) Nothocyon 

 Temnocyon 



Remains of 

 forest in the 

 tuff deposits 



Lepus 



Steneofiber 



Meniscomys 



) (;-'^-, '^i\ ^i_'r> fo v// f / ~<w~/''l-^') ■- RhVpi'tic ^X f low 



Diceratheriinae, 

 ^ Elotherium, 

 P Oreodon 

 (fossils, scarce) 



~pX.epEatLcheTiia 

 ^E-^2r^L50Zl<?^-:£:r^ ? Oreodon 



By permission of the U.S. GeoloKi^'al Survey. 



Fig. 117. 



Section of the Upper Oligocene of the John Day, Oregon. After Merriam and 

 Sinclair. 



Characteristic Mammals 



Anchitheres {Miohippiis, Parahippiis) 



Diceratheres (varied) 



Tapirs 



Chalicotheres (Moropus) 



Entelodonts (last appearance) 



Hypertragulids 



{Hypertragulus, Syndyoceras) 

 Castorids {Steneojiher) 

 Camelids (varied) 

 Oreodonts 



{Pr ornery cochcerus) 

 Dicotylids (varied) 

 Leporids 

 Sciurids 

 Haplodontids 



The older or surviving forms in this 

 final Oligocene phase include advanced 

 species of the oreodont Leptauchenia. 

 Steneofiber is very abundant and char- 

 acteristic; this is its last appearance. 

 The final stages of Aceratherium and 

 Entelodon (Dinohijus) are also observed 

 here. Among the forms which are new 

 or not previously observed are the an- 

 chithere Parahippus, a ])rachyodont, 

 tridactyl horse which becomes very 

 characteristic of the Miocene. Certain 

 new and specialized oreodonts (Mesoreo- 

 don, Phenacocodus) are found, besides the 

 highly characteristic Promerycochwrus 

 and the sm'viving Leptauchenia. It is 



