OQUIEEH MOUNTAINS. 443 



SECTION VII. 

 BEGION SOUTH OF SALT LAKE. 



BY S. F. EMMONS. 



Oquireh Mountains.' — The Oquirrh Moimtains are a high, steep mass of 

 hills lying to the westward of Jordan Valley, about thirty miles in length and 

 from five to ten miles in width, whose summits rise from 5,000 to 6,000 feet 

 above the surrounding plains. They are composed mainly of beds of Car- 

 boniferous limestones and quartzites, which the forces of contraction, acting 

 almost equally in either direction, liave compressed into a series of complicated 

 folds, in which the prevalent strike, however, is in a northwesterly direction. 

 The folding of these beds has been accompanied by a very considerable 

 metamorphism and by the injection of porphyritic dikes, together with sub- 

 sequent mineralization in the more disturbed districts. The southwestern 

 portion of the range, to the west of the main ridge, is a quaquaversal uplift 

 in the Wahsatch limestones, in the centre of which, at Ophir City, a fault- 

 ing at right angles to the longer axis of the uplift has brought up the upper 

 beds of the Cambrian. From Ophir City, as a centre, these limestone 

 strata all dip away, steeply toward the west, more gently toward the north, . 

 east, and south. 



The main crest of the range, between Tooelle and Lewiston Peaks, 

 is the remnant of the flat arch of an anticlinal fold, which descends 

 both to the north and to the south, resulting at the south point of the range 

 in two minor synclinal folds, in Pole Caiion and in the canon south of Lewis- 

 ton, and a similar synclinal fold to the north, in the region between Soldier 

 Caiion and Tooelle Canon. In the region between Tooelle Peak and Con- 

 nor Peak, more particularly in Bingham Canon, which is almost entirely 

 in the beds of the Weber Quartzite, the structure-lines are much more diffi- 

 cult to follow, and evidently the general system of folding observed in the 

 southern portion is much complicated by minor folds ; but its structure is in 

 general that of a synclinal fold in these beds, while at the northern point 



