PARK CITY MINING DISTRICT, UTAH 453 
formation. For the basal member the coarse, massive sandstone 
is taken which lies at the base of the red shale as a whole, and immedi- 
ately overlies a thin limestone. Only a portion of this formation 
occurs within this district, the highest part being marked by a promi- 
nent massive, white sandstone member. 
The non-resistant character of the beds of this formation as a 
whole results in the topographic development along its outcrop of 
even full slopes, which are broken only by benches on the sandy 
members. These slopes are usually thickly covered with aspen, 
rank grasses and brush. They are dry, rarely forming water sources. 
No economic values, either in ore or in stone, have yet been found to 
occur in its members. 
Distribution and thickness.—The formation outcrops in only two 
areas within the district. The principal one is an N-shaped zone 
in the extreme northwestern corner of the area; thence it strikes 
westerly, and is plainly visible in characteristic topographic and 
lithologic development on each of the succeeding ridges to the west 
of Park City which head at Big Cottonwood Canyon. The second 
area, which has never been recognized as such hitherto, is on Pioneer 
Ridge, between Crescent Ridge and Jupiter Hill, where red shale of 
this formation forms the spur between the Kearns-Keith or Sampson 
amphitheater and the Jupiter amphitheater immediately south. 
The best exposure for the measurement of the thickness of that 
portion of the formation which crops in this district is at the west 
side of Thaynes, toward its mouth. This was carefully studied and 
measured, but, owing to frequent interruption by vegetation and 
débris, it is incomplete, and, owing to the probability of deformation 
by faulting, any estimate of the thickness would be of little value. 
In the Big Cottonwood standard section the thickness of the portion 
which crops in the Park City District was found to be 1,300 feet. 
Age and stratigraphic relations.—The age of the Ankareh forma- 
tion, so far as indicated by meagre paleontological evidence, is Per- 
mian. The fossil evidence on which this determination is based 
comprises three lots from the standard Big Cottonwood Section and 
scattering collections from within the Park City District. The lowest 
two lots, one from coarse sandstone, the other from a thin limestone, 
both within 200 feet of the Thaynes formation, belong with the fauna 
