THE OVEELAND EOUTE COUXCIL BLUFFS TO OGDEN. 71 



picturesque gorge eroded by Bitter Creek tlirougli the ridge formed 

 by the hard sandstone of the Mesaverde formation (PL XV, A^ p. 67). 

 Coal is mined from one of the beds that outcrop in the north wall 

 of this iirorge. From the west end of the gorge, just before the train 



enters Ilock Springs, the traveler gets a magnificent view of White 

 Mountain (PL XV, C), to the right, northwest of the town. This is 

 the eastern escarpment of the plateau, made up of beds of Eocene 

 (Tertiary) age that occupy the Bridger Basin. The rocks are the 

 same as those that will be seen at close range from the town of 

 Green River, 



The city of Rock Springs derives its name from a large spring of 

 saline water that issues at the base of a bluff of the water-bearing 



sandstone previously described as occurring between 

 Rock Springs. |]^e Rock Springs and iVlmond groups of coal beds 

 Elevation 6,256 feet, near Poiut of Rocks. Howevcr, water for domestic 



Population 5,778. " -n « j ii • • ii • • • "j. ' 



Omaha 809 miles. "^^c as well as lor use at the mines m this vicmity is 



pumped from Green River^ a distance of 15 miles, 

 with a lift of 179 feet. 



Rock Springs is one of the most important coal-mining centers of 

 the West and ships each year nearly a million tons of high-grade 



bituminous coal. The mines have been operated since 1S68, when 

 the Union Pacific Raikoad reached this point, and some of the older 

 workings extend for miles underground. Mine openings may be seen 

 to the right (north) of the railroad east of the city. .A branch line 

 runs north to Jlcliance and another runs south to mines at Sweet- 

 water, All the mines are in beds of the Rock Springs coal group* 



AVest of Rock Springs the road passes from the Cretaceous forma- 

 tions to the Tertiary beds that occupy the Bridger Basm. The Ter- 

 tiary rocks are conspicuous to the right (north) of the railroad, in 

 Wliite Mountain (see PL XV, <7), which here forms the eastern 

 rim of the basin. The mountain is made up of stratified rocks con- 

 sisting of the light-pink beds of the Wasatch group and the white to 

 light-blue and greenish rocks of the Green River formation. These 

 beds are mclined gently toward the west, so that the hght-colored 

 beds of the middle portion of Wliite Mountain descend to the river 

 level at the toAvn of Green River. 



Near Kanda (see sheet 13, p. 76) the traui enters a narrow winding 

 gorge which was eroded by Bitter Creek and whose walls show the 



westbound traveler first the pink beds of the lower 

 Kanda. p^P^ ^f ^j^^ Wasatch group and then the harder sandy 



Elevation 6,2(M feet, ghales of the Green River formation. These beds are 



made up of a countless number of very thin and sandy 

 calcareous layers separated by equally thin layers of shale, so that 

 the cliffs of this formation have a wonderfully banded appearance. 



