12 SMITHSONIAN MISCKM.A .\ KOL'S COLLECTIONS VOL.53 



is 170 feet thick. In the Eureka District of Nevada, 135 miles 

 northwest of Pioche, this formation Hes between the Prospect Moun- 

 tain quartzitic sandstone and the great Hmestone series and is about 

 200 feet in thickness. In the House Range section, 105 miles north- 

 northeast of Pioche, the formation is 125 feet thick. In the Big 

 Cottonwood section of the Wasatch range, about 125 miles north- 

 east of the House Range, near the old shore line, the Pioche forma- 

 tion is represented by the lower portion of the arenaceous shales 

 which are here 250 feet in thickness. The Pioche formation horizon 

 is next met with to the north where the line of the Canadian Pacific 

 railroad crosses the Continental Divide. At this place the formation 

 is called the Mount Whyte formation. 



Organic Remains. — At all the localities mentioned except that of 

 the House Range, where no fossils except annelid borings and trails 

 have been found, the Lower Cambrian Olenellus fauna occurs. 



Prospect Mountain Formation^ 



Type Locality. — Prospect Peak, Eureka District, Nevada. 



Derivation. — From Prospect Peak, the type locality. 



Character. — Gray to brown quartzitic sandstones. 



Thickness. — At Prospect Peak, 1,500 feet. Estimated 1,200 feet 

 on the western face of the House Range, Millard County, Utah, in 

 the vicinity of Dome and Sinbad Canyons. 



Organic Remains, — Annelid trails and trilobite tracks. Lower 

 Cambrian in age. 



* This formation was first named by Mr. Arnold Hague in 1882, in the 

 Second Ann. Rept. U. S. Geol. Survej-, p. 27, and defined in 1883, in the Third 

 Ann. Rept. U. S. Geol. Survey, p. 254. 



