30 GEOLOGY OF THE HIGH PLATEAUS. 



planes confirmed the belief that the faults really existed. In the middle of 

 the range the obscurity is still greater. Volcanic activity, producing great 

 distortion and destruction of the stratification, has made it impossible to 

 unravel the complications of the displacement. I only know that the upper 

 Jurassic beds appear at the base and again high up in the heart of the 

 range and in a very distorted and more or less metamorphic condition at 

 intermediate places. I have cut the knot, and represented the movement 

 in the stereogram as a simple fault. Near the northern end of the Tushar 

 the fault is shown more clearly, and is there relatively simple, though not 

 without some slight complexities arising from undulation of the strata. The 

 same line of displacements extends beyond the Tushar along the eastern 

 flank of the Pavant, which is the northern continuation of that range. 

 Here it is at first a simple fault, but gradually becomes a monoclinal beyond 

 the town of Richfield by the thrown strata flexing gradually upward until 

 they meet the ends of the beds on the lifted side. 



Opposite Salina it suddenly changes its trend to the northwest and 

 forms the western wall of Round Valley — a depression cutting through the 

 Pavant obliquely. The length of this displacement is about 80 miles. 



The Toroweap* fault cannot be reckoned among the greater faults, 

 though it is so noticeable and conspicuously exhibited that it deserves men- 

 tion. It crosses the Grand Canon near Mount Trumbull, about 1 1 miles east 

 of the Hurricane fault, with a throw to the west of about 700-800 feet, but 

 in the course of about 20 miles to the northward it probably runs out. 

 Very little is known concerning it south of the river. It is a fault of the 

 simplest order. 



The fourth great displacement is the Sevier fault. It commences about 

 35 miles north of the Grand Canon. It makes its first appearance at "Pipe 

 Spring," at the base of the Vermilion Cliffs, and presents a remarkable atti- 

 tude.! Approaching it from the west, the beds are turned down on the 



The Toroweap is a valley opening upon the middle terrace of the Grand Cation from the north 

 sido, li was excavated and its stream .dried up before the commencement of the cutting of the inner 

 ohasm, and its floor, therefore, remains about on a level with the middle terrace. It is a magnificent 

 avenue of approach to :t sublime spectacle of the Grand Canon, bringing the observer to the brink of the 

 inner abyss, where be may look vertically downwards more than 3,000 feet and with more than 2,000 

 feel of wall above him. The name Toroweap signilics "a clayey locality." 



tThore are some indications that ii extends a few miles south of Pipe Spring, but it is covered 

 with soil and sand. 



