oli Headden — Broivn Artesian Waters of Costilla Co., Colo. 



into a basin and evaporate, would not give the pure sodic car- 

 bonate found in this deposit. 



The natron was found in August, 1907, forming a mass of 

 crystals live inches thick covered by an inch or more of a yel- 

 lowish mother liquor. The upper part of the crystalline mass 

 showed a thin layer of bright needles or thin prismatic crystals : 

 these did not effloresce, yielded water in the closed tube and 

 consisted of sodium carbonate. It was not feasible to select 

 material pure enough for analysis. I took this layer as con- 

 sisting of the mineral trona. 



The mass of crystals had effloresced so badly by the time I 

 was able to analyze it, that I dried the material thoroughly 

 before analyzing it. A water determination, however, was 

 made on some of the best material that I could, under the 

 circumstances, select and yielded 59*161 per cent of water. 



Analysis of thoroughly dried Analysis of the residue from 



salt-mass from Soda Lake. the mother liquor.* 



Si0 2 0-128 Si0 2 0-405 



S0 3 ..: 0-184 S0 3 2-235 



CI ._- 0-138 CI 2-409 



C0 3 41-060 C0 3 36-016 



Na,0 57-875 Na 2 46*991 



K 2 G__ 0-824 K 2 12-347 



100-209 100-403 



= C1... -030 = C1 ._ -543 



100-179 99 860 



*This residue contained traces of iodine and lithia, also of titanic and 

 boric acids. 



The conditions obtaining in this artesian basin which 

 permit of the confinement of these waters to a somewhat 

 sharply limited area are certainly not clear. There are no 

 reasons for assuming the existence of a separate basin in 

 this section though its waters are very distinct in their proper- 

 ties. There is no evident source of the sodium carbonate, for 

 granting, as we must, that vegetation may have at some time 

 been abundant in this section, which is indicated by the fossil 

 wood, the humus and the marsh gas, it does not suffice to 

 explain the presence of the sodium carbonate. We might 

 assume that beds of carbonate exist somewhere in this terri- 

 tory, but we have no proof that this is a fact. No observations 

 indicating such deposits have been made in putting down the 

 numerous wells of this section. The small deposits mentioned 

 in this article are the only known ones and these are 

 confined to the surface, or within a few feet of it. I have 

 understood that borings have been made with the idea of 

 finding such deposits, but without success. 



