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 will 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 Final 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 Key ; 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 Sari 

 Gorgonio 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 tor 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 10 miles an ascending slope of 40 feet per mile ; 

 then for 6 miles, one of 89 feet per mile. We arc now at the point 133 miles from the mouth of 

 the Gila. The natural slopes along the line of survey are 



