454 STUDIES FOR STUDENTS 



[A being lowest] : Horizon C, true Uinta beds 600 feet thick, 

 sandstones and clays brownish and reddish, ferruginous . . . . 

 " Horizon B, 300 feet thick. Soft coarse sandstones and clays. 

 Horizon A, 800 feet thick. Hard brown sandstones immediately 

 overlying the Green River shales." Commenting upon the above 

 field notes Osborn says 1 : "These excellent observations supply 

 one of the most important links in the American lake faunal 

 chain, namely that between the Washakie 2 and the Uinta. The 

 explorations of the present year, 1895, may modify these results, 

 but it is certain we have now not only established a complete 

 faunal transition from the Bridger and Washakie beds upon the 

 one side, to the true Uinta level or Horizon C upon the other, 

 but have demonstrated a closer connection between the fauna of 

 this basin and that of the lowest White River Miocene." 



THE AMYZON FORMATION 



Under this name Cope has described beds in Elko county, 

 Nevada ; in South Park, Colorado ; and in central Oregon. He 

 regards them as belonging to the "later Eocene or early Miocene 

 eras." 3 King described and mapped the same beds of Nevada 

 as of Green River age. 4 



Cope thus describes the beds of Oregon: "The regions of 

 the John Day River and Blue Mountains, furnish sections of the 

 formations of central Oregon Below the Loup Fork fol- 

 lows the Truckee [Neocene] group, so rich in extinct mammalia, 

 and below this a formation of shales. These [shales] are com- 

 posed of fine material and vary in color, from a white to a pale 

 brown and reddish-brown They contain vegetable remains in 

 excellent preservation, and undeterminable fishes. The Taxo- 

 dium nearly resembles that from the shales at Osino, Nevada, 

 and on various grounds I suspect that these beds form a part of 



1 Loc. cit, pp. 74, 75. 



2 Beds belonging to the upper part of the Bridger substage lying east of Green 

 River in southern Wyoming. Cf. Clark, U. S. Geol. Surv., Bull. No. 83, pp. 117, 142. 



3Amer. Nat., Vol. XIII, p. 332, 1879. 



4 U. S. Geol. Explorations of the 40th Parallel, Vol. I, Systematic Geol., p. 393, 



