64 H. G. Hanks — Hanksite in California. 



western margin of the large depression lies a small basin 

 known as "Borax lake proper," which has approximate dimen- 

 sions of one mile and a half in length by half a mile in width. 

 From this secondary lake, and the dividing ridge referred to 

 below, most of the borax produced has been taken. 



Between Borax Lake, which is a few feet higher than the 

 general level, and the wide alkali flat, there is a slight ridge, 

 which acts as a natural dam and prevents the water from 

 flowing away. It is covered with crude borax which is be- 

 lieved to be of semi- volcanic or solfataric origin. This barrier 

 prevents the water of the borax lake from flowing to still 

 lower depressions on the great alkali flat beyond. The water 

 of Borax Lake is a dark brown highly concentrated alkaline 

 liquor, having a density of 28 degrees Beaume. The salts 

 obtained from it by crystallization contain carbonate, chloride 

 and bi-borate of sodium, with much organic matter. There 

 has never been an exhaustive analysis made, which would, no 

 doubt, be very interesting. 



For a number of years it was planned to explore or prospect 

 the underlying formations both as a matter of general inter- 

 est, and in the hope of finding the source of the borax and 

 other salts. After much delay, work was finally commenced 

 in 1887, and carried on under many difficulties, owing to the 

 nature of the ground. The bottom of the lake was found to 

 be of a remarkably sticky, tenacious, plastic clay, described as 

 being "tough as wax." To avoid the difficulty of keeping 

 back the alkaline water by coffer dams or other similar con- 

 trivances, the first experimental well was commenced on the 

 ridge before mentioned. It was sunk by spring-pole drills to 

 a depth of three hundred feet. The following is a section 

 carefully kept by Mr. Searles : 



1. Two feet salt and thenardite. 



2. Four feet clay and volcanic sand containing a few crystals 

 and bunches of hanksite. 



3. Eight feet volcanic sand and black tenacious clay with 

 bunches of trona of black shining lustre from inclosed mud. 



4. Eight-foot stratum, consisting of volcanic sand in which is 

 found glauberite, thenardite and a few flat hexagonal crystals of 

 hanksite. 



5. Twenty-eight feet of solid trona of uniform thickness. Other 

 borings show that this valuable mineral extends over a large area. 



6. Twenty-feet stratum of black, slushy, soft, mud, smelling 

 strongly of hydrosulphuric acid, in which there are layers of 

 glauberite, soda and hanksite. The water has a density of 30° 

 Beaume. 



7. Two hundred and thirty feet (as far as explored), of brown 

 clay, mixed with volcanic sand, and permeated with hydrosul- 

 phuric acid. 



