CHAPTER XXIY. 
OF THE PERMANENT SUPPLY OE WATER, AND OF TTIE FEASIBILITY 
OF OBTAINING ABUNDANT SUPPLIES BY ARTESIAN BORINGS. 
Only a portion op the route deficient in the supply op water.—Extent op this district.—Geological summary.—Meteor" 
ology.—Region op summer rains.—Elevation op the district.—Annual fall op rain.—Causes op the diminution op rain 
westward.— Quantity absorbed by the soil.—Contrast op a north temperate and an inter-tropical zone.—Substitutes 
FOR ARTESIAN WELLS.—WATER TANKS.— ORDINARY WELLS.—GENERAL CONCLUSIONS.-LOCALITIES OP NATURAL SU Jg LY ON ROUTE.— 
Cook’s spring.— Rio mimbres.—Ojo de la vacca.—Valle del sauz.—Playa de los pimas. 
Along parallel 32°, the shortest route by which the Pacific can be reached, the difficulty 
of obtaining water is one which is shared in common with any other travelled road over the 
continent more northward, and a difficulty which, regarding the route itself, may be obviated. 
It is only over a portion of the route in which the deficiency of water is felt; it is to this 
locality only that attention will be directed, and if it can be shown that in these less favored 
districts a sufficient supply of water can be had the argument applies a fortiori to the whole 
route. 
This district is comprised between the Eio Bravo and the San Pedro, a distance of 253 miles ; 
is not traversed by any large river, nor subject to a large fall of rain; to arrive at any conclu¬ 
sions concerning the facility of obtaining water sufficient for railroad wants, two classes of cir¬ 
cumstances will require to be noticed. 
1. The geological conditions. 
2. The meteorological conditions. 
1. Geological. A detailed description of the structure of the region has been given, and the 
sections appended illustrate the description. It is unnecessary, therefore, here to state more 
than that the first 85 miles west of the Rio Grande is broken up by basaltic upheavals and 
overflows ; that from Cook’s spring to Penascitas succeeds a district which, though not so 
broken, is yet traversed by porphyry upheavals, producing faults, and having horizontal strata 
only over very small areas, so small as not to be conveniently tapped. 
The elevated lands of Penascitas and Ojo de la Vacca are the foot hills of a chain of igneous 
rock, (Burro mountains,) which lie northward. These lands are the dividing ridge of the 
waters of the continent along this parallel; those on the east running southward into the Gulf 
of Mexico, and those on the west rolling north (via the Gila) into the Gulf of California. 
West of these elevated lands the country drops by a succession of troughs or valleys, sepa¬ 
rated from each other by short unconnected ranges of felspathic and granitoid rock, running 
N.N.W. and S.S.E. These valleys or flats have their rock basis of carboniferous limestone 
and overlying sandstones, and are four in number : 
1. Small valley, with lagoons. 
2. Valle de los Playas. 
3. Valle del Sauz. 
4. Playa de los Pimas. 
