262 GEOLOGY OF THE HIGH PLATEAUS. 



The gorge itself is the work of erosion, and its apparent history is 

 worthy of passing mention. The course of this valley cuts obliquely across 

 the great monoclinal flexure which forms the western flank of the Fish Lake 

 Plateau, and was in process of excavation before that flexure was formed. 

 Like almost all other valleys, its position and direction are quite independ- 

 ent of the structural features of the country, and when the final uplifting 

 took place it did not divert here the course of the drainage. Its only effect 

 was to increase the amount of excavation to be done. The position of the 

 great gorge upon the shoulder of the monocline and running obliquely 

 across it is very striking, and might have given rise to a great deal of specu- 

 lation as to its origin, were we not able to apply to it the exceedingly simple 

 solution of the antecedence of drainage courses to the structural features 

 of the country and their persistence in spite of changes of great magnitude. 

 At first the interior of the gorge suggests a vast caldera, like those described 

 by Lyell in the Cape de Verde Islands or the Val del Bove at ^tna. But 

 it is neither a caldera nor a Val del Bove, as a study of the surrounding 

 country abundantly proves. 



Passing across the nearly level summit a distance of 2 miles we reach 

 the southeastern verge of the plateau, whence we may look down upon the 

 beautiful surface of Fish Lake. This sheet of water, about 5 J miles in length 

 and a mile and a half in breadth, is walled in by two noble palisades. The 

 one on which we imagine ourselves to stand — the plateau summit — is about 

 2, GOO feet above the water ; the other is nearly a thousand feet less lofty. 

 The lake itself is about 8,600 feet above the level of the sea. No resort 

 more beautiful than this lake can be found in Southern Utah. Its grassy 

 banks clad with groves of spruce and aspen ; the splendid vista down 

 between its mountain walls, with the massive fronts of Mounts Marvine and 

 Hilgard in the distance ; the crystal-clear expanse of the lake itself, com- 

 bine to form a scene of beauty rarely equaled in the West. 



The subjects of geological interest to be found in the vicinity are nu- 

 merous. First may be mentioned the origin of the lake itself. Mr. 

 Howell's first impression was that glaciation had played an important part 

 in its excavation. Mr. Gilbert expressed the opinion that it might have 

 been caiised by the sinking of a block between two faults. But I have 



