BORAX IN AMERICA. 359 



of dotted spots, individually of no great extent, scattered over the 

 desert regions east of the Sierra Nevada. Most of them are without 

 designation, but a few are marked " Soda Flat," " Salt Marsh," etc. 

 They all have probably a common origin ; they are places which long 

 ago (how long we can not tell) were covered with water, since removed 

 by solar evaporation. Each consists of an extent of entirely flat sur- 

 face of dried mud, sometimes absolutely bare, sometimes covered with 

 saline deposits. It had been known for years that these deposits were 

 both what is there universally called " alkali" (carbonate of soda) and 

 salt. But it was not until 1871 that much attention was drawn to the 

 fact that several of them contained also deposits of borates, though 

 published mention had been made some time earlier that these existed 

 there. 



The number of these "marshes," which are marked by borate 

 deposits, it is impossible to state, as so large an extent of that arid 

 region remains as yet very imperfectly known. A sketch of one, 

 however, gives the characteristics of all. 



One of the largest is known as the " Columbus Marsh." It is situ- 

 ated in Esmeralda County, about two hundred and fifty miles nearly 

 due east from San Francisco, and about one hundred and sixty miles 

 south of Wadsworth, on the Central Pacific Railroad. The portion 

 last abandoned by the water, and now covered by saline deposits, ex- 

 tends about ten miles from east to west, and three from north to south, 

 with an extension on the south into Fish Lake Valley, forming an arm 

 fifteen miles long by one to three miles wide. Not all parts of this 

 extent are equally rich in salines, neither is the character of the de- 

 posits the same at different parts, though it must have formerly been 

 covered with one sheet of water, of presumably a uniform quality or 

 nearly so. 



A space of several hundred acres in one part, for instance, is covered 

 with a crust of chloride and carbonate of soda, through which the foot 

 breaks at every step ; but the black mud beneath is filled to the depth 

 of six to twelve inches with borate of lime aggregated in nodules, 

 which, when broken open, show a beautiful pearly- white mass of satiny 

 luster. These are the ulexite, and are commonly called "cotton-bolls." 

 They can be picked out by hand like the kernel of a nut, separating 

 clean and clear. 



Immediately adjoining the ground thus rich in ulexite is a wide 

 stretch barren of everything, except a little chloride and carbonate. 

 Just beyond this come five or six hundred acres, thickly covered with 

 borate of soda, so little contaminated with sand or anything else as to 

 crystallize out, by simple solution, eighty per cent of its weight in 

 pure borax. Over vast extents of this surface I have seen the crude 

 borax in its granular, semi-crystalline form lying from fifteen to twenty- 

 four inches in deptl^, while, at the distance of a quarter to half a mile, 

 the borate of lime was in similar abundance. The supply of borax 



