THE EOCENE OF NORTH AMERICA 449 



Wortman believes that the upper fossiliferous horizon con- 

 tains several layers, and that their vertical range is somewhat 

 greater than that of the lower horizon." Matthew states that 

 the "Upper and Lower Puerco beds do not contain a single 

 species in common, and only three or four genera pass through. 

 The two faunas are entirely distinct. Dr. Wortman proposes to 

 call the upper beds the Torrejon formation, retaining the name 

 Puerco for the lower beds." 1 Scott correlates the Puerco with 

 the Cernaysien of Europe. 2 



THE WASATCH FORMATION. 



The Wasatch formation occurs in a large area in Utah, Wyo- 

 ming, and Colorado. It is equivalent to the Vermillion Creek of 

 King; Bitter Creek of Powell; and Coryphodon beds of Marsh. 

 The fossils indicate that the rocks were deposited in fresh water. 

 ** From the outcrops thus broadly sketched it is clear that a 

 single lake extended from longitude io6° 30' to 112 , stretch- 

 ing northward probably over the greater part of the Green River 

 Basin, and southward to an unknown distance." 3 



The Wasatch beds lie upon the Cretaceous with a discrepancy 

 in dip, as shown by King, of 0° to 25 ° in many places. Clark 

 says: 4 "The Wasatch strata throughout much of their extent 

 are conformable to the Laramie, but in western Wyoming and 

 eastern Utah a marked unconformity is exhibited." King thus 

 describes the Wasatch formation, which he names Vermillion 

 Creek: 5 "It is made up of a heavy gritty series at the base, 

 which in the region of Vermillion Creek and north of Evanston 

 is gray, but as displayed at Echo Canyon and East Canyon Creek 

 is characterized by the presence of enough red sandstones and 

 clays to give it more of a brick or in places a deep pinkish 

 color. The middle members are of finer material and are more 

 intercalated with clays, while the upper part of the series has 

 shown wherever the group comes in contact with the Green 



'Science, n. s., Vol. VII, p. 852, 1897. 2 Science, n. s., Vol. II, p. 499, 1895. 



3 King: U. S. Explorations of the 40th Parallel, Systematic Geol., Vol. I, p. 374. 

 *Loc. cit., p. 139. 5 Loc. cit., p. 375. 



