REPORT OF CAPTAIN HUMPHREYS TO THE SECRETARY OF WAR, 1855. 17 



This result having been reported to the Department, by your directions, measures were taken 

 to supply additional tubing to Captain Pope, who has been instructed to resume the work on 

 the Llano. 



In the opinion of the officer charged with the operation they had, at the depth of six hundred 

 and forty feet, closely approached coal measures, and he was convinced that a clear stream or 

 reservoir would have been found twenty feet lower. From his report and accompanying diagram 

 it appears that, at five hundred and seventy feet, a stratum of dark blue shale of the coal 

 measures was pierced. It is highly probable that the water, which appeared at the depth of 

 six hundred and forty feet, pressed up through the lower portion of the stratum of sandstone 

 which they had b^en boring through for the last sixty feet, would have risen to the surface in 

 large quantities. As the first supply of water rose to within two hundred and ninety feet of the 

 surface, it might reasonably be concluded that, if another supply were attained three hundred 

 feet below the source of the first supply, it would rise to the surface ; the bottom of the boring 

 was within twenty feet of this point when the second supply was pressed up through sandstone. 

 The level attained by the first supply of water was that of Delaware spring. At Independence 

 spring, which is west of Delaware spring, and six hundred feet above it, the upper carboniferous 

 formation of the Guadalupe mountains begins. If the strata of sandstones, indurated clays 

 and marls, found between these two springs, should extend under the Llano Estacado, parallel 

 to each other and of equal thickness, it was probable that, at a depth of six hundred feet below 

 tlie point at which the first supjjly of water was reached, (coming from the same level as 

 Delaware spring,) the second supply would be had coming from the upper carboniferous strata 

 and the level of Independence spring ; but as the blue shale of the coal measures was reached 

 at one-half this depth, it would ai^j^ear that the strata are about three hundred feet apart at the 

 point where the boring was made, instead of six hundred feet, as they are between Delaware 

 and Independence springs. These conclusions are dependent upon the fact reported by Captain 

 Pope, that the dip of the strata is very slight, being nearly coincident with the slope of the 

 surface of the ground. Both supplies of water in the well were clear, pure, and palatable, free 

 from any impurities appreciable by the tests at the command of the geologist. Dr. Shumard, 

 An important result of this boring is the probable existence of coal in the carboniferous forma- 

 tion which appears upon the surface at the foot of the G-uadalupe mountains. 



The instructions of the Department required Captain Pope, after the successful completion of 

 the well on the Llano Estacado, or the demonstration of its impracticability, to make borings at 

 certain points west of the Kio Grande on the route to be examined by Lieutenant Parke's party, 

 in order to determine the practicability of artesian wells there, and the depths at which water 

 can be had (by ordinary wells) at the dryest season, and the thickness of the water-bearing 

 strata. By the time this duty is completed, it is probable that he will have received the addi- 

 tional tubing necessary to the successful completion of the artesian well on the Llano Estacado, 

 and will then be enabled to resume that work. 



The importance of obtaining large supplies of water on the interior plains and basins, by the 

 construction of artesian wells at moderate cost, is too apparent to need exposition. 



The greater part of the rain and other precipitation in those arid regions falls upon the 

 mountains, and percolating through the loose debris on their flanks, descends below the surface 

 of the plains, appearing again, sometimes at great distances, in sj^rings and streams — the 

 sources of rivers. 



On the plains and table lands of Asia, which so closely resemble those of North America that 

 3CC 



