PARKS CIV SVEN TING DEST RI CT. OLA 441 
exposed in this district is an oblong tract which extends south from 
Park City about 3 miles, with an average width ofa mile. From Bald 
Mountain an irregular, much broken arm extends eastward between 
two great faulted zones, and to the south and southwest about the 
eastern end of Bonanza Flat are isolated horses in intrusives. This 
quartzite forms the outcrops on the slopes which inclose Park City 
onall sides. It is particularly well exposed on the salient bluffs west 
of the city, and is deeply incised by each of the canyons which lead 
south up to the mines. Characteristic outcrops have been revealed 
in Woodside Gulch by cutting the King Road between the Alice and 
Woodside properties; in Empire Canyon in the vicinity of the adits 
to the Daly Judge and to the Alliance tunnels, and in upper Ontario 
Canyon. 
The thickness of the portion of this formation which appears in 
this district cannot be determined precisely, because nowhere within 
the area was a continuous exposure observed. The Ontario No. 3 
shaft and workings cut “‘ Ontario”’ quartzite, dipping about 20 degrees, 
to a depth of 1,620 feet, or a thickness of approximately 1,500 feet. 
The collar of the shaft lies on the side of a canyon which has been cut 
deep into the formation below its upper contact. This contact is 
exposed elsewhere to the north and northwest, but the thickness of 
quartzite which has been removed by denudation down to the strati- 
graphic horizon in which the collar of the shaft is located is uncer- 
tain, except that it is several hundred feet. The thickness of Weber 
quartzite exposed within the district may thus be regarded as approxi- 
mately 2,000 feet. ‘The minimum thickness of the underlying por- 
tion would be 1,500 feet. The accurate determination must await 
the working-out of structure and measurement of any possible great 
faults. Pending that, it may be tentatively considered as 3,500 feet. 
The thickness of the part exposed on the north side of Big Cottonwood 
Canyon was 1,340 feet. King and the geologists of the Fortieth Parallel 
estimated the thickness exposed in Weber Canyon to be 6,000 feet. 
Age and stratigraphic relations.—The geologic age of the Weber 
quartzite was regarded by the early geological workers in this region 
as “‘Upper Carboniferous.”” They did not find fossils in the quartzite 
itself, but based this conclusion on the stratigraphic relation of this 
formation to fossiliferous limestones above and below. 
