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 been 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 
the point at which the first supply 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 appear 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 Guadalupe 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 Rio 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 springs and streams—the 
sources of rivers. 
On the plains and table lands of Asia, which so closely resemble those of North America that 
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