Ileadden — Brown Artesian Waters of Costilla Co., Colo. 305 



Art. XXI Y. — The Brown Artesian Waters of Costilla 

 County, Colo., their Relations to Certain Deposits of 

 Natron or Soda, and what they teach / by ¥m. P. Headden. 



The San Luis Valley, in the southern part of this state, 

 presents several interesting questions, among them its drainage 

 and its artesian wells. The fact that there is an artesian basin 

 in this valley was discovered by accident in 1887. I have no 

 official figures at my command in regard to the number of such 

 wells in the valley, but I have heard it estimated at more than 

 3000. They are put down with such ease that it is difficult to 

 obtain accurate records, either in regard to their number or the 

 strata passed through by the borings. The strata consist of 

 alternate layers of clay and sand which scarcely attains to the 

 size of fine gravel. The depth at which flows are met with 

 varies exceedingly. South and west of La Jara, water is 

 struck at very shallow depths ; a four-inch, cased well on the 

 place of Mr. Ormond is 77 feet deep, the water rises a few 

 inches above the casing and is very cold, 44° F. Even shal- 

 lower wells than this are recorded, which is no cause for sur- 

 prise as it is very probable that some of the springs in the 

 eastern and southern parts of the valley are due to the artesian 

 pressure in the valley and not to surface waters finding an 

 exit in the usual manner. The ground and. surface waters of 

 the valley are, so far as my knowledge goes, of bad quality, 

 whereas these springs and the artesian wells yield excellent 

 waters. Even wells of 1000 feet depth yield waters carrying 

 less than 16 grains to the imperial gallon and 45 per cent of 

 this mineral matter is silicic acid. The springs and wells 

 agree in the amount of total solids carried in solution, ranging 

 from 5*8 to 20*7 grains to the gallon, and are characterized by 

 a high percentage of silicic acid, namely, from 26 to 46 per 

 cent of the total solids. 



The percentage of flowing wells obtained is very large ; fail- 

 ures are very rare, but an occasional one is met with. Mr. W. 

 K. Hapney informs me that he put down a well, a few miles 

 west of Alamosa, to the depth of 1004 feet, without obtain- 

 ing a flow — at least the well was a failure. This is certainly 

 remarkable, for at Alamosa they have two of the strongest 

 flows in the valley. It is difficult to obtain full enough data 

 to justify one in venturing a suggestion in explanation of such 

 a failure. There are no reasons for supposing that the strata 

 are not continuous throughout this section, nor have we any 

 reason, except perhaps this failure itself, for assuming that a 

 fold may exist at this place. 



Am. Jour. Sci.— Fourth Series, Vol. XXVII, No. 160.— April, 1909. 

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