CORRELATION A>D PALEOGEOGRAPHY 



243 



Formations. 







Lower Bridger fauna. 



Lost Cabin 



True Wind River fauna. 





{ 



Lysite 



Fauna of genera common to Wind River and 

 Wasatch. 



" Wasatcji " 



True "AVasatch" fauna. 





1 



Ralston 



Sub. Wasatch fauna. Undiscovered hfe zones. 

 "Fort Union." 





" Puerco " fauna. 



The manner in which this result has been attained by the overlapping 

 of mammalian life zones in four different sections is shown in more de- 

 tail in the accompanying all-Eocene table. 



The true Wind River fauna contains Eotitanops (early true titano- 

 there) as well as Lamb doth eiium. The Lysite fauna and the true Wa- 

 satch fauna lack Lainbdotherium and Eotitanops. Systemodon is lim- 

 ited to the true Wasatch (Knight) fauna. The sub- Wasatch fauna of 



Leptauchen/'a 

 ,, clays'' 



enuz zome Protoceras 



sandstones " 



Oreodon clays''* 



Me tamynodon 

 sancfstones''^ 



Titano therium 

 clays and 

 zon^ sandstones'^^ 



Figure 8. — OlUjocene of South Dakota. Section of Titanotherium Beds 



(After Wortman) 



Upper : Leptauchenia Zone • 

 Middle : Oreodon Zone 

 Ix)wer : Titanotherium Zone 



