THE NONMETALLIC MINERALS. 



413 



plied is of a fair degree of purity, as will be seen from the following analyses of two 

 samples of the crystallized substance, taken from opposite shores of the lake: 



Some 14 miles southwest of Laramie, in Albany County, Wyoming, 

 there exist deposits of sulphate of soda, such as are locally known as 

 "lakes." The deposits in question comprise three of these lakes lying 

 within a stone's throw of one another. They have a total area of about 

 65 acres, the local names of the three being the Big Lake, the Track 

 Lake, and the Red Lake. Being the property of the Union Pacific 

 Railroad Company, they are generally known as the Union Pacific 

 Lakes. 



In these lakes the sulphate of soda occurs in two bodies or layers. 

 The lower part, constituting the great bulk of the deposit, is a mass of 

 crystals of a faint greenish color mixed with a considerable amount 

 of black, slimy mud. It is known as the "solid soda," of which an 

 analysis is given below. 



Constituents. 



Anhy- Crystal- 

 drous. lized. 



CaSO 4 

 MgCl s 



NaCl . 



1.45 



0.77 

 0.21 



38.43 



Insoluble residue (at 100 C.) . . 



81.63 

 1.82 

 1.64 

 0.21 



85.30 

 13.86 



Total chloride calculated as NaCl equals 1.16 per cent. This, calculated on 100 

 parts anhydrous Na 2 S0 4 , equals 3.22 per cent NaCl. 



This solid soda is stated to have a depth of some 20 or 30 feet. 

 Borings were made a number of years ago under the direction of the 

 Union Pacific Railroad agents, but, as the records have been mislaid 

 or lost, with what results is not definitely known. There is nothing 

 to prove that the depth is not less than stated above. 



Above the solid soda occurs the superficial layer of pure white 

 crystallized sulphate of soda. This is formed by solution in water of 

 the upper part of the lower body, the crystals being deposited by 



