150 EEPOET UNITED STATES GEOLOGICAL SUEVEY. 



CLAY. 



As a rule, the accumulations of clay are too sandy to be used for other 

 purposes than that of manufacturing adobe or brick. In some of the 

 dry alkali flats clay may be found, however, which would answer very 

 well for the preparation of stone-ware and pottery. If too great an ad- 

 mixture of alkali be found with the clay, this can readily be removed by 

 a process of washing. 



ALKALI. 



Under this very general term we comprise a series of products, all of 

 which represent a certain commercial value. "Alkaline" deposits are 

 found very frequently within our district. They occur in great profusion 

 throughout the low country south of the Sweetwater Hills. Along the 

 Sweetwater Kiver and in the low country northward they are met with. 

 No thick deposits of such substances were found, but it is probable that 

 they occur in certain regions at some inconsiderable depth. 



From the annual report of 1870 I extract a number of analyses of 

 alkaline efflorescences collected within our district and examined by A. 

 S. Ford.* 



1. From alkaline lake two miles east of Eock Independence: 



Per cent. 



Sulphate of soda (NaOSOs) 73.17 



Chloride of sodinm (Na CI) 3. 85 



Carbonate of soda (by loss) 22.98 



100. 00 



2. Alkaline efflorescence seven Nniles west of Saint Mary's Station, in Sweetwater 

 VaUey: 



Per cent. 



Sulphate of soda (Na O S O3) 88.93 



Chloride of sodium (Na CI) 11.63 



100. 56 



3. From deposit near Pacific Springs : 



Per cent. 



Sulphate of soda (NaOSOs) 82.23 



Chloride of sodium (NaCl) 3.95 



Carbonate of soda (by loss) , 14. 82 



100. 00 



4. From deposit of alkaline pond near Big Sandy Eiver : 



4 (a). From upper part of bank where deposition commenced : 



Per cent. 



Sulphate of soda (NaOSOg) , 64.65 



Chloride of sodium (NaCl) 35.46 



100. 11 

 4 (6). From half-way between upper and lower limit of deposit : 



Per cent. 



Sulphate of soda (NaOSOs) 94.92 



Chloride of sodinm (NaCl) 5.23 



100.15 

 4 (c). From lowest part of pond: 



Per cent. 

 Sulphate of soda (NaOSOs) 100.00 



According to Mr. Ford's statement, this last deposit occurred in the 

 form of slender orthorhombic prisms. Potassium was not found in com- 

 bination with any of the acids or with chlorine in these deposits. 



*The analyses are directly copied, giving the old formulae. — E. 



