44 



CENOZOIC MAMMAL HOKIZONS 



the significant fact that some of the more advanced stages occur in 

 the base of the Wind Kiver deposition, (5) by the introduction of 

 true primitive Dinocerata or uintatheres, of primitive titanotheres, 

 of new Primates, which are not found in the Wasatch, and of more 

 highly speciahzed Tgeniodonta (Stylinodon) . 



The writer's conclusions at present are (1) that the base of the 

 Wind River, or Wind River A, began to be deposited during the 

 upper stage of the Wasatch deposition of the Bighorn Basin (see p. 41), 



B 

 800' 

 -900' 



A 

 A-OO' 

 -500' 



Sathyopsis 

 zone 



m 

 m 



Levels < 

 unrecorded 



Eotitanops 

 " ^aiaeoi 

 boreal 



( Palaeosyops) 

 }/is 



Bathyopsis 

 Tr/temnodon 



Coryphodon 

 Bathyopsis 

 Phenacodus 

 \ Eohippus 



LambdoiherivLTW Lambdothen'um 

 zone 



Hyopsodus 



-Red beds 



Sciurai^us 

 Pelycodus 



Fig. 5.— Columnar section of the Wind River basin, based on the descriptions of Hayden and Loomis. 

 The horizontal banding of the red and greenish-gray beds in Wind River B is very regular. The 

 occurrence of Eotitanops and Bathyopsis in the upper Wind River is not certainly recorded. 



and was thus contemporaneous with most of the upper fossil-bearing 

 strata of the Bighorn Basin Wasatch; (2) that positive evidence of 

 an overlap may be derived from the study of the faunae; (3) that 

 the Lamhdotherium zone occurs in each. 



Geologic divisions. — Hayden's exploration of 1859-60, as reported 

 in 1869, « afforded materials for the first complete section we have 

 of the Wind River Tertiaries. His '4ower division," of 400 to 500 



a Geol. Rept. Explor. Yellowstone and Missouri Rivers, by F. V. Hayden, assistant [to Col. William 

 F. Raynolds, U. S. Engineers], Washington, 1869. 



