REPORT OF CAPTAIN HUMPHREYS TO THE SECRETARY OF WAR, 1855. 
15 
The first, under the command of Lieutenant John G. Parke, topographical engineers, was 
instructed by the letter of the Department of October 2, 1854, to determine the practicability of 
constructing a railroad from the waters of the bay of San Francisco to tbe plain of Los Angeles, 
by the Salinas river valley, and through the spurs of the Coast Range, which extend to the sea 
coast near Point Concepcion, or, if that was found to be impracticable, by the coast route; to 
make certain explorations in the Great Basin, in connexion with the route of the 35th parallel, 
and between the Pimas villages on tbe Gila and the Rio Grande; the attention of the party 
being particularly directed to such examinations in tbe latter region as would show tbe degree 
of practicability of constructing artesian and common wells. These duties have been thoroughly 
and satisfactorily executed, and the party has just returned to Washington from the field. A 
rough reduction of portions of the field-work, at the most difficult points, shows that a railroad 
route from the headwaters of the Salinas, through the spurs of the Coast Range, direct to the 
plains of Los Angeles, is not practicable; whilst that along the coast route is eminently so. 
With equal length, it has the advantage over the route by New (Williamson’s) and Tay-ee- 
cbay-pah passes, of a less sum of ascents and descents, less elevation, (the greatest attained 
being only 1,350 feet above the sea,) less cost of construction, and of passing continuously 
through a settled and cultivated country. The grades are favorable, the greatest required 
being, with a cut of 60 feet at the summit, 125 feet per mile for the space of 15 miles, (ascend¬ 
ing and descending;) and this, it is believed, can be reduced to 100 feet per mile, by a tunnel 
1,000 feet long. 
The labors of the party will develop the topography of a district that was before unknown, 
or the nature of which was greatly misconceived ; and will show a practicable railroad route, 
with easy grades, connecting the valley of Salinas river with the head of Tulare valley, by the 
Estrella, a tributary of the Salinas, and the Estero, a plain lying within the Coast Range, and 
connected with the Tulare valley, near the Canada de las Uvas. The exploration in the Great 
Basin was successfully executed, demonstrating that the Mojave river is a stream of the Great 
Basin, and does not flow into the Colorado at any time ; an elevated ridge separating the basins 
of the two rivers. 
The topographical examinations between the Pimas villages on the Gila and Dona Ana, or 
El Paso, on the Rio Grande, have resulted in many important improvements upon the line of 
survey of last year. They have established the practicability of constructing a railroad between 
those points, by the Gila river, to the mouth of the San Pedro, and up that stream to the vicinity 
of the line of 1854; a route possessing great advantages over all others in this region, since, 
from the Pimas villages to the point of departure from the San Pedro, a distance of 166 miles, 
it passes along the cultivable valleys of those streams, instead of over bare jornadas. The ridge 
of mountains east of the San Pedro is crossed by a more direct route than that of the old line, 
and the Puerto del Dado of the Chiricahui mountains is avoided, that range being turned on 
the north by a gap or break lying between it and Mount Graham. The length and the cost of 
construction of this route will be about the same as of that examined by Lieutenant Parke, in 
1854 ; the summits to be overcome will be fewer in number, the elevations less, the grades more 
gentle, and the supply of water greater ; these, with the great advantage first mentioned, con¬ 
stitute this the best route yet made known in that region. The results of the examinations with 
reference to the supplies of water make it probable, from the form and geological structure of 
the basins and plains, that ordinary wells, at distances not exceeding twenty miles, would 
furnish abundant supplies, distances not too great for the economical working of passenger 
