SALINA CAITON— THE JURASSIC WEDGE. 



163 



it has now become a generalization of great importance. Its formula is 

 exceedingly brief. The principal drainage channels are older than the dis- 

 placements. 



Salina Cafion cuts through the southern continuation of the great 

 monoclinal at a point Avhere its rise is a minimum, and nearly midway 

 between the Wasatch Plateau on the north and the Sevier and Fish Lake 

 Plateaus on the south. Even here it plunges into a wall forming the 

 uplifted side of a gi-eat fault of which the shear could not have been much 

 less than 3,000 feet, though fully 2,000 feet of upper beds have been re- 

 moved from the uplift by erosion. After a course of about 23 miles the 

 canon opens into the Sevier Valley. It carries a fine stream, whose watei's 

 join the Sevier at the town of Salina. Along the descent of this stream 

 the beds dip more rapidly than the stream descends. This relation between 

 the course of a drainage channel and the inclination of the strata is not the 

 usual one in the Plateau Country; on the contrary, the strata much more 

 frequently dip upstream, and rivers usually emerge from cliffs instead of 

 entering them. In this respect Salina Canon is an exception, though not 

 an isolated one. 



A remarkable displacement is found along the eastern side of the Sevier 

 Valley, between Gunnison and Salina. A narrow belt of rocks of Jurassic 

 age is thrust up, forming a chain of foot-hills and bad lands, and the later 

 Tertiaries are seen to flex upward against their western sides and terminate 

 in a "hog-back," while they abut almost horizontally against their eastern 

 sides. A small remnant of Tertiary beds is here and there found as a thin 

 capping lying upon the Jurassic beds unconformably, and patches of vol- 

 canic rock farther southward are also seen to cover them. The belt of 

 Jurassic rocks nowhere exceeds two miles and a half in width, but its 

 length is nearly 40 miles, extending from a point about 7 miles south 

 of Manti along the base of the great monoclinal and the throw of the Sevier 

 fault as far as Monroe, where it ends, to all appearances, somewhat ab- 

 ruptly, or perhaps disappears under the great mass of volcanic rocks which 

 form the loftiest part of the Sevier Plateau. These older beds dip east- 

 ward, always at a high angle, which sometimes passes the vertical. This 

 inclination was attained, without doubt, in part before the commencement 



