450 J. M. BOUTWELL 
Thickness 
in feet 
4 Limestone, gray-blue, fossiliferous. 
10) Shale, olive, with three fossiliferous argillaceous limestones. 
5 Limestone . 
370 Limestone, blue; shale, olive-brown; sandstone, calcareous; alternating 
series, varying much in color and texture, fossiliferous. 
Talus, containing shale regarded as top of Woodside formation. 
Distribution and thickness—The Thaynes formation is one of 
the two most extensively exposed formations in this district. On 
the western flank of the Park City anticline it forms both of the inclos- 
ing walls of Thaynes Canyon from head to mouth, all the middle and 
headward portions of White Pine Canyon, and thence strikes south- 
west into Big Cottonwood Canyon. It is again seen in the main fault 
zone of the district overlying the great mines. Thus it forms the promi- 
nent ledges west of the upper portion of Empire Canyon, just oppo- 
site the Daly Mine, the spur extending from the Daly West mine to 
Morgan Knob, and the cliffs which overlook the Daly Judge amphi- 
theater. On the eastern flank of the anticline the cropping of this 
formation is exposed about the heads of Heber, McCune, and Pocatello 
gulches, and at the extreme southeast crops in a triangular area just 
north of Cottonwood Canyon. 
The best measure of the thickness of this formation was obtained 
in Big Cottonwood Canyon, where, as shown above, the upper part 
amounts to 630 feet, the ‘‘mid-red”’ shale to 115 feet, and the lower 
part to 445 feet, the whole formation thus aggregating 1,190 feet. 
Within the Park City area proper no exposure was found suitable 
for measurement, so complex and universal was the deformation in 
this region. The difference in thickness of exposures of this forma- 
tion on the eastern and western sides of the district may be apparent 
rather than actual, as on the Heber road near the top of the eastern 
exposure red-shale crops which is probably the “‘ mid-red”’ shale, and 
the same is true in the Cottonwood exposure. It would thus appear 
that the eastern exposures embrace a portion of the formation only— 
that is, the part lying below the ‘‘mid-red”’ shale, the upper portion 
being either truncated by intrusives or buried by extrusives. 
A ge and stratigraphic relations.—Excellent fossil evidence indicates 
that the geologic age of the Thaynes formation is probably Permian. 
