SOUTHERN WASATCH MOUNTAINS, UTAH 443 
Summary of structural evidence.—The ‘‘lower’’ limestone, for- 
merly called the “ Ute (Silurian) ” by the Fortieth Parallel Survey, is 
proved to be a part of the Mississippian and older limestones over- 
ridden by a slab of the Cambrian quartzite which was formerly 
called ‘‘Ogden”’ and referred to the Devonian. This overthrust of 
eastward dip, was broken by at least two parallel reverse faults of 
steep westward dip which were formed during the domal uplift which 
accompanied the granite intrusion. Still later normal faults further 
complicate the structure. 
Stratigraphy.—The stratigraphy east of the reversed faults, or 
from the “upper” quartzite belt upward, consists of a thin belt 
of Cambrian shale, which grades upward into the great limestone 
belt. The lowest limestone beds may be Cambrian also, but the 
greater part of the limestone contains Mississippian fossils. No 
careful measurements of thickness were made, but a rough estimate 
shows that there cannot be much more than 2,000 ft., and maybe 
much less, of pre-Mississippian limestone and shale. This is in 
marked contrast to the stratigraphy in the northern Wasatch Moun- 
tains and in the Uinta Mountains to the east. In the former, 
Cambrian limestones and shale above the quartzite aggregate 
5,415 ft.* and are themselves separated from the Mississippian by 
1,000 to 1,200 ft. of Ordovician and 1,000 to 1,500 ft. of Silurian 
and Devonian limestones.” In the latter, on the contrary, the entire 
great limestone belt is only 700 to 1,000 ft. thick, and Weeks: 
correlates its lowest beds with the Mississippian. The upper part 
he assigns to the Pennsylvanian. The Silurian and Devonian have 
been shown by Weeks and Ferrier‘ to thin southward and eastward, 
and they may not be represented so far southward as the Cotton- 
wood district; but the exact stratigraphic relations cannot be 
accurately determined by mere reconnaissance work. 
™C. D. Walcott, ‘“‘Cambrian Brachiopoda,”’ Mon. U.S. Geol. Survey, No. 51, 
Vol. I (1912), 148-52. 
2K. Blackwelder, op. cit., pp. 527-28. 
3 F. B. Weeks, “‘Stratigraphy and Structure of the Uinta Range,’ Bull. Geol. Soc. 
America, XVIII (1907), 432-41. 
4F. B. Weeks and W. F. Ferrier, ‘“‘ Phosphate Deposits in Western United States,”’ 
Bull. U.S. Geol. Survey, No. 315 (1906), p. 451; F. B. Weeks, “Stratigraphy and 
Structure of the Uinta Range,” Bull. Geol. Soc. America, XVIII (1907) (correlation 
table). Silurian and Devonian are not represented in the Uinta Range. 
