Headden — Brown Artesian Waters of Costilla Co., Colo. 307 



it. On the southeastern limit of this area there seems to be 

 one instance in which an area of colorless water is overlapped 

 by this area of brown water, but this is exceptional and while 

 easily explicable if true, needs confirmation. 



The brown water area is surrounded by an area of colorless 

 water and the limits, at some points, are fairly well defined. 

 I observed two wells near the southern limit of the brown 

 water ; one 500 feet deep yielding a brown water carrying 

 104'0 grains total solids per gallon ; less than two miles to the 

 south of it another, 880 feet deep ; here the water was scarcely 

 colored at all and carried only 38 grains per gallon ; this well 

 emitted a considerable quantity of combustible gas, but was 

 free from hydrogen sulphide, and the water was nearly taste- 

 less. The wells which yield gas most freely seem to be at the 

 outer edge of the brown water area and have considerable 

 depth. I do not know of any well close to the San Luis lake 

 on the west side, but the nearest one that I now recall yields a 

 brown water and a fair quantity of gas ; its depth is, according 

 to my information, upwards of 900 feet. At the northeast 

 corner of the lake and close to it there is a 500-foot? well, 

 which yields a white water, tasting slightly of hydrogen sul- 

 phide but otherwise of good quality. A short distance south 

 of this, and directly east of the lake, is a well 300 feet deep, 

 which furnished a colorless water, but this well is no longer 

 flowing. 



It is as good as impossible to obtain the logs of these wells, 

 for they have been sunk through clay and sand with such ease 

 and rapidity that it would be somewhat difficult for anyone to 

 make an accurate record, which may be more fully appreciated 

 when it is considered that wells as much as 400 feet deep have 

 been begun and finished in a day. Some fragmentary informa- 

 tion is furnished by the debris washed out of the drill holes 

 such as is shown by the presence of fish vertebrse and, within 

 the brown water area, fragments of wood. The presence of 

 the wood suggests an explanation for the brown color of the 

 water, i. e., that there is enough vegetable matter buried here 

 to give rise to a sufficient quantity of humus to color it. 



One of the questions arising in connection with this valley 

 is, what becomes of the water flowing into it? This valley 

 receives the water from a large drainage area, but the visible 

 discharge of water from it amounts to only 540,000 acre feet 

 annually or about 75 second feet, which is less than the loss of 

 the Rio Grande as it enters the valley. I have not been able 

 to obtain even an approximate idea of the total amount of the 

 water entering the valley, but it is evidently very much in 

 excess of the visible outflow. 



