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Show 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 valley proper are all volcanic. They are chiefly 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 GO 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 considerable tracts upon the summit of the Awapa Plateau near its western verge and upon the northwestern edge of the Aquarius. PAUNSAGUNT PLATEAU AND PART A WLLEY. Crossing 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 Paunsagunt* Its length is about 25 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 Playfield. Its western front is formed by the uplifted side of the Sevier fault. Its eastern front is a cliff of erosion looking down into the Upper Paria Valley; a valley of erosion draining 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 continuations 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 Paunsagunt 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 *Pamisagunt means tho "place of the beavers. |