HINTZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH 121 



pear and give another thousand feet of fine-grained white rock. The 

 series thus defined above the disconformity which terminates the Missis- 

 sippian strata constitutes what is here called Weber quartzite. In the 

 Park City district to the east, BoutwelP' reports only the upper portion 

 of the Weber quartzite as seen in outcrops. 



"The middle and basal portions of the formation, which are not present in 

 this area, outcrop in prominent cliffs just south of the district. Except for a 

 few thin limestone beds near its top, the middle portion is massive quartzite, 

 but in the lower part, the intercalated limestone members increase in number 

 and thickness." 



The middle and basal portions here mentioned correspond with part of 

 the upper and middle parts of what is called Weber quartzite in this 

 report. The thickness given in Boutwell's section is 1350 feet, which he 

 regards as too small and gives a tentative estimate of 3500 feet. The 

 exact thickness is still doubtful, as continuous exposures could not be 

 found within the Cottonwood district, but 3500 feet is probably too great. 

 Somewhat more than 2000 feet is thought to be more nearly correct. 



In the type locality in Weber Canyon, 30 miles to the north, the For- 

 tieth Parallel geologists^^ have given the thickness as 5000 to 6000 feet. 

 This figure has been questioned by Blackwelder,^^ who follows Weeks^* 

 and separates the low^er red beds of that section from the Weber and calls 

 them the Morgan formation. There is, however, no doubt that the de- 

 velopment of the Weber quartzite in Weber Canyon is considerably 

 greater than in Big Cottonwood and that the thickness is subject to 

 variation from place to place. In less than 15 miles north of Weber 

 Canyon, it disappears altogether and the Park City limestone which 

 overlies the Weber in all of the southern sections rests directly on Mis- 

 sissippian limestone. Blackwelder describes the unconformity as one of 

 low angular discordance, the beds of early Mississippian age being slowly 

 truncated, over the edges of which the Park City limestone rests. As we 

 go southward, the Morgan formation and Weber quartzite appear be- 

 tween the Mississippian limestone and Park City formation. The Park 

 City beds thus overlap the Weber quartzite and Morgan red beds, and 

 going still lower rest on early Mississippian. 



It is also important to note that in Weber Canyon, the Morgan forma- 

 tion rests on much higher Mississippian beds than in the northern sec- 

 tions. This fact may be explained in several ways. The presence of a 



a' J. M. BoUTWELL : V. S. Geol. Surv. Prof. Paper 77. p. 45. 



28 C. King : V. S. Geol. Expl. 40th Par., Vol. I, p. 161. 



29 E. Blackwelder : Op. cit., p. 531. 



so F. B. Weeks : Unpublished report of U. S. Geol. Surv.. quoted by Blackwelder. 1908. 



