84 ROUTE NEAR THE THIRTY-SECOND PARALLEL. 
From the Rio Mimbres to the Rio San Pedro, 152.5 miles. 
Intermediate is Valle de Sauz, 72 miles, where water is always found; 25 miles further 
on, is a spring in the Puerto del Dado. 
From the San Pedro to Tuczon, 53 miles. 
From Tuczon to the Gila, 79 miles. 
There are springs between some of these points which it is not necessary to particularize. 
For the working of a railroad after construction, the greatest even of these distances, 152.5 
miles, is not too great to be overcome by special arrangements. But for the working parties 
engaged in building the road, supplies of water must be had at every few miles. Fortunately, 
the formation of these basins is such as to afford, at comparatively small cost, sufficient supplies 
of water at distances convenient for the construction of the road. During certain portions of the 
year, the bottoms of some of these basins are converted into lakes, which may be drained into 
tanks. 
The following description of these basins by Dr. C. C. Parry, geologist upon the Mexican 
boundary survey, shows that artesian wells, of no great depth, can be resorted to successfully: 
‘* All the so-called ‘ mesa formations’ and ‘jornadas’ of this district belong to a distinct system 
of basin deposites, tertiary, or post-tertiary, in age, and still showing in outlines of greater or 
less extent the original areas in which these depositions were made. These basins exhibit, 
quite uniformly, central depressions, and margins gently rising to the limit of the mountain bound- 
aries. The ‘mesa,’ or table-land character, is exhibited only along the line. of river-valleys, as 
high bluffs, the result of denuding forces subsequent to the original basin depositions. 
“These deposites are characterized, as a whole, by a great preponderance of porous mate- 
rials, consisting of gravel, sands, marls, and clays. 
“The natural supplies of fresh water for these open wastes are derived from uncertain accu- 
mulations of rain products in small reservoirs, or occasional permanent springs, the latter gen- 
erally occupying situations in close proximity to mountain ranges. 
“All these basins not directly connected with the Rio Grande valley receive and absorb the 
drainage of their respective mountain boundaries, except in the higher elevations, rarely showing 
running water, unless as the temporary result of local rains. 
‘“The above indications are favorable to the formation of aqueous substrata, which may be 
reached by sufficiently deep boring, and when located at the lower depressions of these basin 
areas, the water would necessarily be brought to the surface.” 
Nearly all the rain that falls upon the scattered mountains probably passes underneath the 
surface before reaching the foot-slopes, since the coarse angular debris of the mountains extend 
high up their sides, permitting the water to percolate through and descend into the permeable strata. 
It will be noticed that nearly all the mountain streams and drains sink before reaching the 
plains, and others sink on the plains when they reach a porous soil. Where a deep vertical cut 
has been made in the strata, as, for instance, in the valleys of large rivers, they reappear, 
running under the permeable and above the impermeable strata. From these facts and consid- 
erations it appears that this country, at times almost destitute of water on its surface, has sub- 
terranean ponds, and streams, at no great depth below, which can be made to furnish water at . 
the surface, in some instances by artesian wells, and in others by ordinary wells. 
This opinion is confirmed by that of Mr. Blake, geologist of the party commanded by Lieutenant 
Williamson, whose description of the series of small basins lying in the Great Basin applies strictly 
to those under consideration. The formations are identical. Mr. Blake has detected the existence 
of regularly stratified tertiary formations in these basins, in which the success of artesian wells 
is certain. This question will, however, be satisfactorily solved by boring, as the economy of 
construction is involved to some degree by the facilities of finding water sufficient for working 
parties during the construction of the road. 
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