GYPSUM OF THE RED BEDS. 135 



solution, and long-standing outcrops are found to be rotten and crumbling. 

 In some localities, especially in the Red Valley near Sun Dance Hills, where 

 the red clay lies nearly horizontal, holes or sinks have been worn in the 

 gypsum layers, into which the local drainage flows, gradually dissolving the 

 gypsum and enlarging the sinks. 



Its readiness of solution is also shown by its occurrence as an efflores- 

 ence on surfaces of clay or rock, where it has been deposited by evaporat- 

 ing waters. The waters which flow through it or in contact with large 

 surfaces are usually hard and medicinal. 



It has a snowy white color, is massive and crystalline in structure 

 with numerous little sparkling facets, and in outcrops unaffected by the 

 weather is dense and firm. Occasionally small deposits of a pink, fibrous 

 gypsum of great beauty are found, but it was never found in ciystals. 

 When long acted upon by the weather it becomes porous and soft and 

 resembles chalk in texture. 



Notwithstanding the enormous quantities in which it occurs, it will 

 probably never, or at least for very man}' years, be of any commercial 

 value There is no market in which it can compete without great disad- 

 vantage in the matter of transportation. 



The brilliant brick- red color of the Red Bed clay, intensified as it often 

 is by a strong contrast with the snowy white of the included gypsum and 

 the green of the scanty herbage, makes it one of the most conspicuous 

 members of the rock system of the Hills. It is easily eroded and washed 

 away by the action of rains and streams. Limited on each side by a hard 

 rock, its broad outcrop has been hollowed into a valley between two ridges. 

 On one side is ihe underlying Carboniferous series faced by the purple 

 limestone of the Red Beds, and on the other is the cliff capped by the 

 lower sandstone of the Cretaceous. Between them is the valley, broad 

 and open, completely encircling the Hills, and one of the most prominent 

 features of the topography. Its prevailing red hue distinguishes it from 

 all others, and it is appropriately entitled the Red Valley. From what- 

 ever side the Hills are approached the same, or nearly the same, topo- 

 graphical features are passed over in succession. By a gradual rise from 

 the Plains, or sometimes by crossing a series of low cliffs, one reaches the 



