Headden — Brown Artesian Waters of Costilla Co., Colo. 313 



but it was necessary to use as much as 20 grams of the residue to 

 establish the presence of lithia and bromine. The iodine, titanic 

 and boric acids, on the other hand, were easily detected. 



We have thus added to the fact that the brown waters are 

 the only ones in the valley which, to our knowledge, carry 

 sodium carbonate as the principal salt in solution, this further 

 consideration, i. e., that the mother liquor from the crystals of 

 natron resemble the brown waters in that it contains small 

 quantities of iodine, lithia, titanic and boric acids. The potas- 

 sium salts in the mother liquor of the lake are no more abundant 

 than might be expected due to their concentration in this 

 liquor as the soda salts crystallize out ; but there may be a 

 question as to whether the iodine, etc., show an increase corre- 

 sponding with the degree of concentration which has taken place. 



Apropos to the extent of these soda deposits. I may state 

 that there are, to my knowledge, four depressions in which 

 crystallized sodium carbonate, natron, is found. Three of these 

 are quite small but the fourth is larger. When I last saw this 

 there was probably a third of an acre entirely covered with a 

 layer of natron, but it has at times been considerably larger 

 than this. Mr. W. H. Falke, the present owner, tells me that 

 he has measured the crystalline mass when it had a maximum 

 thickness of forty-eight inches. There would have been no 

 trouble in finding spots where the mass of crystals would have 

 measured thirty inches in thickness when I last visited the place. 



There is a question which will certainly suggest itself to 

 everyone in any way familiar with our western conditions, i. e., 

 whether the surface waters of the section may have contributed 

 to the formation of these deposits. It is well known that 

 water percolating through our surface soils gives rise to 

 efflorescences and incrustations on evaporation. I have never 

 seen deposits owing their origin to this source, comparable to 

 this in extent or thickness ; still it remains to show that these 

 salts — this carbonate of soda did not come from the surface 

 soil. I have analyzed the surface and also the ground waters 

 from a territory which I believed would be most likely to give 

 me results favorable to the assumption that such might be the 

 source of the carbonate. The surface waters contain principally 

 sulphates and chlorides with some carbonates ; the ground waters 

 contain the same mixture, the sodium chloride being rather 

 more abundant. The efflorescences occurring in this section 

 are essentially sodium sulphate with subordinate quantities of 

 calcium and magnesium sulphates. The aqueous extract of the 

 soil contains large quantities of sulphates with only a little 

 carbonate. We have then in the surface waters, the ground 

 waters, the water-soluble portion of the soil, and in the efflor- 

 escent salts gathering on the soil an entirely different mixture 

 of salts and one which, were it to flow through or over the soil 



