CALIFORNIA ALKALINE AND BOBACIC LAKES. 227 



waters of Great Salt Lake, Utah, and those of other saline and alkaline 

 lakes of the "West, and appear to be the larva of a two-winged fly which is 

 described by the late Prof. Torrey under the name of Ephydra Californica, 

 and by A. S. Packard as Ephydra gracilis^'^ 



A specimen of water taken from Owen's Lake in January, 1866, had a spe- 

 cific gravity of 1.076, and contained 7128.24 grains of solid matter per gal- 

 lon. The composition of this residue was found, calculated on an imperial 

 gallon, to be as follows : 



Chloride of sodium , 2942.05 



Sulphate of sodium 956.80 



Carbonate of sodium 2914.43 



Sulphate of potassium 122.94 



Phosphate of potassium 35.74 



Silicate of potassium 139.34 



Organic matter 16.94- 



7128.24 

 In adition to the substances above enumerated, iodine was present, but 

 only in such minute proportions that its amount could not be estimated. 

 It is also to be observed that since, for convenience of carriage, the sample 

 of this water operated on was reduced by evaporation to one-fourth of its 

 original bulk before being brought to this country for analysis, it is prob- 

 able that some alkaline sesquicarbonates may have been originally present. 



The incrustations which at certain periods of the year accumulate to the 

 extent of many hundreds of tons on the shores of this lake mainly consist 

 of carbonates of...sodium, in which the proportion of sesquicarbonate is some- 

 what variable ; in some specimens examined monocarbonates were alone 

 present. Besides carbonates of sodium, these deposits contain three per 

 cent, of chloride of sodium, and about five per cent, of sulphate of sodium, 

 together with traces of silica. 



It was proposed some years since to erect works on the eastern shore of 

 Owen's Lake, for the purpose of refining this deposit, for the manufacture 

 of merchantable carbonate of sodium ; but whether this idea was ever car- 

 ried out, I am not aware. The only serious obstacles to the success of such 

 an enterprise would aj)pear to arise from scarcity of fuel, and the great 

 distance of the lake from a shipping-port. 



As this lake continuously receives the waters of a considerable and con- 

 stantly-flowing river, while it has no apparent outlet, it follows that it must 

 act the part of a huge evaporating basin, in which the salts introduced by 

 the not apparently saline water of Owen's Eiver become concentrated to an 

 alkaline brine. The rocks on either side of the valley through which the 

 river flows are, to a very large extent, composed of granites, lavas, and ba- 

 salts, from the decomposition of the feldspars in which the alkaline salts of 

 the lake have doubtless been derived. The very small proportion of potas- 

 sium salts present in these waters is remarkable, for although, from the cir- 



*8ee Playden, " Geological Survey of Montana, Idaho, Wyoming, and Utah, 1872, p. 744. 



