HI^TZE, GEOLOGY OF WASATCH MOUNTAINS, UTAH U7 



Mercur Section 



In Lewiston Canyon, at the head of which is the little mining town 

 of Mercur, there is exposed a great anticlinal fold, the axis of which runs 

 northwest and southeast, somewhat diagonal to the general trend of the 

 range, which is north-south. Lewiston Canyon cuts directly across the 

 fold, exposing the anticline on both sides of the canyon. The lowest 

 rocks brought up are of Lower Carboniferous age, and the highest ex- 

 posed, directly over the axis of the fold, are also of that age. The crest 

 of the range to the east rises on the east limb or flank of this anticline, 

 and here are exposed the rocks of Upper Carboniferous age. The section 

 thus exposed is as follows : 



Feet 



4. Upper intercalated series 5,(XX)-6,000 



3. Great blue liuiestone 5,000 



2. Lower intercalated series 000 



1. Lower blue limestone 200 



Above the Upper Intercalated series comes the great Weber quartzite 

 8000 feet thick exposed on the eastern slopes of the Oquirrhs at Bingham 

 and northward. Below the Lower Blue limestone, in Dry Canyon, which 

 parallels Lewiston Canyon on the north, are several hundred feet of 

 Lower Carboniferous limestone, below which come 2000 feet of Devonian, 

 Silurian, Ordovician and Cambrian strata. There is thus a great series 

 of sediment exposed in these three localities ranging from the Cambrian 

 to the Upper Carboniferous. 



Fossils obtained from the Lower Blue limestone by Mr. Spurr,^" and 

 examined by Professor Schucheii;, were found to be of Mississippian age. 

 The limestone is a dark blue, semi-crystalline rock, in which zaphrentoid 

 corals seem to be the most abundant fossils. 



Above the Lower Blue comes the Lower Intercalated series, 600 feet 

 thick, the lowest member of which is a sandstone 100 feet thick. Above 

 this come frequent alternations of siliceous and calcareous sediments 

 (silicilutytes and calcarenytes). Two parallel sections measured on the 

 steep bare walls of the canyon three-fourths of a mile apart showed con- 

 siderable thinning of these beds toward the east, even in this slight 

 distance. 



Above these intercalated beds is a great limestone succession 5000 feet 

 thick, broken only in two places by very dark calcareous shales, one about 

 a thousand feet below the top and the other about the same distance from 



»J. E. Spdrr : "Geology of Mercur District, Utah," U. S. Geol. Surv., 16th Ann. Kept.. 

 Part II, pp. 371-377. 1894. 



