GENERAL VIEW OF THE SEVIER PLATEAU. 227 



have sculptured ridges of erosion which trend that way. If we view the 

 Sevier Plateau from the north, its transverse profile is alone seen, and the 

 tabular summit slightly incHned is conspicuous to the eye. But if we 

 view it from the east or west, its long siunmit is seen in many places to be 

 somewhat rumpled and even sen-ated by the ridges of erosion and by the 

 old volcanic remnants viewed endwise. 



The northern end of the Sevier Plateau is not well defined. A long, 

 gentle ramp, deeply scarred and much wasted by erosion, begins a little south 

 of Salina and ascends southward to the summit. It is best appreciated as 

 we journey up the Sevier Valley from Salina to Richfield. We then 

 observe the whole platform of the country to the east of us gradually 

 gaining in altitude through a distance of 20 miles, until from being a 

 thousand feet above us at Salina it becomes 5,800 feet above us opposite 

 Richfield, and there presents to the west a stupendous battlement of nearly 

 vertical wall above and abrupt spur-like slopes below, thrusting their but- 

 tresses beneath the valley plain. For nearly iO miles this tremendous 

 escarpment is quite massive and unbroken, simple in form and more than 

 a mile in height. Opposite Monroe a large amphitheater has been exca- 

 vated in the plateau by a plexus of streams, and may be likened to a huge 

 bowl filled with mountains. From this point southward the plateau wall is 

 notched repeatedly by profound ravines heading far back in the table, 

 until, at a distance of about 32 miles south of Monroe, the plateau is cut 

 completely in twain by the East Fork Canon. From this gap southward 

 30 miles the southern division of the plateau presents a very few incon- 

 spicuous breaks, and terminates in a low wall at a rather lofty and broad 

 transverse valley known as the Panquitch Hayfield. The eastern front of 

 the table looks down into Grass Valley, but from a much smaller eminence, 

 both because the eastern front is absolutely lower than the western, and 

 because Grass Valley is absolutely higher than Sevier Valley. The 

 descent into Grass Valley along the northern and central parts of the pla- 

 teau is rather abrupt, frequently precipitous ; but along the southern part 

 it is very gradual. 



The Sevier Plateau is composed chiefly of volcanic sheets of grand 

 dimensions and enormous cumulative thickness, and of immense beds of 



