24 ROUTE NEAR THE THIRTY-SECOND PARALLEL. 
The region between the Rio Grande and the Pimas villages on the Gila, just above which 
point the latter leaves the mountain region, may be described as a great plain, interrupted 
irregularly and confusedly by bare, rugged, abrupt, isolated mountains or short ranges, around 
or through the passes in which a railroad may be constructed with quite practicable grades. 
The mean elevation of this plain, or series of basins into which the ridges divide it, is about 
4,100 feet; the mean elevation of the summits of the passes through the ridges is 4,700 feet, 
the highest, through the Chiricahui range, being 5,180 feet. Except through the passes, the 
surface is so smooth as to require but little preparation to receive the superstructure of a rail- 
road; and even in the two most difficult of the passes, the natural slope of the ground may be 
used for a railroad until the construction of the road reduces the cost of materials and supplies 
to the lowest rates. In one of these two passes (the Chiricahui) the steepest natural slope is 
194 feet per mile for 2} miles. In the second pass the steepest natural slope is 240 feet per 
mile for three-fourths of a mile. Both these grades are within the power of a thirty-ton engine, 
carrying 200 passengers and baggage. 
In one case deep cutting in rock, or a tunnel near the surface, at the summit, with heavy 
side cutting and high embankments for short distances; and, in the other, a short cut of 60 feet, 
probably through rock, are proposed by Lieut. Parke, to attain grades of 46 feet and 90 feet 
per mile, or less by increasing distance. 
The great difficulty experienced in crossing this district is in the long distances over which 
no water is found at certain seasons. The survey by Lieut. Parke was made during the dryest 
season of the year, and, irrespective of the springs found at intermediate points, the whole 
distance between the two rivers, Rio Grande and Gila, may be divided into five spaces, varying 
from 80 to 53 miles in length, at the termination of which large permanent supplies of water 
are found at the most unfavorable season of the year. 
These spaces and points are— 
Kromithe Rio'Grande to the Rio Mimbres:...:c-cccccesssssceee sneak aanctinanicenenctnteie aetebienttos 71 miles. 
From the Rio Mimbres to the stream of the Valle de Sauz................0seceseeeeseeeeeees 72 es 
Hromithe Valledewauz-to the San Pedrotsceet es peeeceseens eae etaes ecm sepecesseeeciess decid 800 He 
Hromithe SaniPedrorto "Lnezomaisach.cs.sedecwe sce eceebocten derteanen cine totem tesoe ste Ge wcbuteG: onebre bot ak 
from’ /Tuezonmtoythe Gila: {82.0 0c ts ceeseee chmeeeree cnn cee ne chow cme eee eee aatbaceecensmmcen’s [ene (Ge 
Not counting the stream of the Valle de Sauz, the distance from the Rio Mimbres to the San 
Pedro is 152 miles; which distance is not so great that railroad trains could not cross it 
without water, special arrangements having been made for the purpose. But this is the worst 
aspect of the case. At other seasons the supply of water is more abundant, and lakes and 
ponds are formed upon the plains, which may be drained into tanks; and the geological 
formation is such as to indicate the existence of sufficient supplies of water beneath the surface, 
which may be brought to it by artesian wells. 
The line proposed by Lieut. Parke leaves the Rio Grande near Fort Fillmore, 35 miles 
from Molino, between which points the river, where confined to one channel, is about 300 
yards wide, crosses the district just described, and enters the valley of the Gila near the Pimas 
villages, the elevation above the sea being 1,365 feet. The route then follows this river to its 
junction with the Colorado, a distance of 223 miles, with a general slope of 5.6 feet per mile. 
The Gila, in this distance, flows through a plain with occasional mountains, ridges, and 
peaks; its valley is highly favorable to cheap construction from its generally smooth surface, 
and from not being liable to freshets. 
From the point now attained, the nearest port in our territory is San Diego, but the passes 
of the intervening Coast range are very difficult, if not impracticable, and the route is forced 
northward to the San Gorgonio Pass, which is much the most favorable of the passes in the 
Coast range explored by Lieut. Williamson for this route. It is an open valley, from two to 
five miles wide, the surface smooth and unbroken, affording, in its form and inclination, every 
facility to the building of a railroad. The entrance of this pass is 133 miles from the mouth 
