86 ROUTE NEAR THE THIRTY-SECOND PARALLEL. 
To resume the route: We have now reached the Gila, seven miles above the Pimas villages, 
the elevation above the sea being 1,365 feet. From this point to its junction with the Colorado, 
the valley of the river is highly favorable to the construction of a railroad. There wiil be no 
necessity for embankments against freshets, but trifling occasional cutting and filling; and in those 
instances where the hills close in upon the river, there is ample space for the road without heavy 
cutting. The elevation at the mouth of the river being 108 feet, and the distance between the 
two points 223 miles, we have a general slope of 5.6 feet per mile, which, from the favorable 
character of the ground, may be assumed as the grade of the road. 
Water and fuel for working parties are sufficient, though no grass. Logs may be driven down 
the Gila from the Mogoyon mountains at its source, from the Pinal Lleno, and down the San 
Francisco and Salinas rivers, from the pine forests on the former, and the mountains at the 
sources of the latter. But it may be found more economical to receive all the supplies of lumber 
needed from the western portion of the road, either from the San Bernardino mountains and pass, 
or from the harbors of San Pedro or Diego, or, should it be found desirable to establish one, 
from the depot near the mouth of the Gila. 
3. FROM THE MOUTH OF THE GILA TO SAN FRANCISCO. 
The most favorable point for crossing the Colorado is at the junction of the Gila where the river 
is narrowest, 650 feet wide, and has bluffs on both banks. 
The direction that the road should take across the desert intervening between it and the foot of 
the Coast range, depends in part upon the position of the pass by which it crosses this mountain 
chain. ‘There are two passes known and explored. Warner’s, the more southerly of the two, 
will require five miles of excavation in granite and mica-slate for the full width of the road, the 
grades varying from 130 to 190 feet per mile. Thence to San Diego by the San Luis river there 
is a practicable route, but at great cost of cutting on the river to San Luis Rey ; thence along the 
seacoast numerous gullies will require bridging. The distance from the mouth of the Gila, over 
the desert, to the entrance of this pass, is 80 miles; thence to San Diego is 150 miles. The San 
Gorgounio or San Bernardino Pass, on the contrary, is remarkably favorable. It is an open valley, 
from two to five miles wide, the surface, smooth and unbroken, affording in its form and inclination 
every facility and no obstruction to the building of a railroad. Leaving the Colorado, it would 
be better to keep upon the alluvial soil, passing to the south of the sand-hills, and thus avoid the 
hard gravelly plain, where it would be necessary to bore considerable depths for water, and 
where the success of artesian wells is not certain; and it is also desirable to avoid the drifiing 
sand of the gravel plain. But this obliges the road to pass over Mexican territory. The entrance 
of the San Gorgonio Pass is 133 miles from the mouth of the Gila in a straight line, over a smooth 
and nearly horizontal plain, which requires scarcely any preparation for the superstructure of a 
railroad. Thirty or thirty-five miles of this lies upon the gravel plain; the remainder passes 
over alluvial soil, which only needs irrigation to be fruitful. The first work is to construct wells at 
every few miles for the use of the working parties. On the alluvial soil, water will, no doubt, be 
found at a depth of 30 feet; and should deep or artesian wells fail to give a supply on the gravel 
plain, the expense of hauling it to the working parties for that distance will not be serious. Suf- 
ficient fuel for culinary purposes will, perhaps, be found on the alluvial plain—none on the gravel 
plain; but it can be supplied from the mountains at about double the cost in the eastern 
States. 
The elevation of the mouth of the Gila is 108 feet, and the grade across the plain nearly 
horizontal. Approaching the pass, we have for 104 miles an ascending slope of 40 feet per mile ; 
then for 6 miles, one of 89 feet per mile. We are now at the point 133 miles from the mouth of 
the Gila. The natural slopes along the line of survey are— 
