paunsAgunt plateau. 



251 



Valley. In the southern portion, the lift of the Awapa fault has brought 

 up the Tertiary strata and exposed them in the wall of that plateau. The 

 rocks exhibited in the valle}^ proper are all volcanic. They are cliiefly 

 trachytic, and only here and there project above the masses of alluvial 

 matter which is gradually burying them. Just south of East Fork Canon 

 a few large coulees of basalt are seen, and they appear to have emanated 

 from the vicinity of the Awapa fault. They form broad terraces, rising one 

 behind another, and ending in cliff and talus CO to 80 feet in height. They 

 have been much battered by erosion and are no doubt of considerable 

 antiquity. Basalts of similar character are found overspreading consider- 

 able tracts upon the summit of the Awapa Plateau near its western verge 

 and upon the northwestern edge of the Aquarius. 



PAUNSAGUNT PLATEAU AND PARIA XJiALLEY. 



Cx'ossing the Panquitch Hayfield we reach the foot of a very gentle 

 slope, which rises almost insensibly to the southward, forming a plateau of 

 the ordinary type called the Paunsdgunt.* Its length is about 2h miles 

 and its width from 8 to 12 miles. It lies in the southward prolongation of 

 the major axis of the Sevier Plateau, from which it is separated by the 

 shallow depression of the Panquitch Hayfield. Its western front is formed 

 by the uplifted side of the Sevier fault. Its eastern front is a cliif of ero- 

 sion looking down into the Upper Paria Valley ; a valley of erosion drain- 

 ing into the Colorado. There is a fault a little distance from the eastern 

 wall running north-northeast, but the Paunsagunt is upon the thrown side 

 of it. So great has been the erosion in Paria Valley that, notwithstanding 

 the greater altitude of the strata within it than the altitude of their con- 

 tinuations in the plateau, the valley is from 3,000 to 3,500 feet below the 

 plateau summit. If the denuded strata could be restored, they would make 

 the locus of the valley nearly 2,000 feet higher than the plateau. 



The Paunsdgunt is composed wholly of sedimentary beds: Eocene 

 resting upon Cretaceous. The stratification is sensibly horizontal, though 

 at several localities on the eastern flank the junction of the two series is 



•Patins^unt meauH the "place of the beavers." 



