SAN PEDRO ROUTE—ARAVAYPA ROUTE. 
25 
At the Tres Alamos the stream is about fifteen inches deep and twelve feet wide, and flows 
with a rapid current over a light, sandy bed, about fifteen feet below its hanks, which are 
nearly vertical. The water here is turbid, and not a stick of timber is seen to mark the 
meanderings of its bed. In the gorge below, and in some of the meadows, the stream 
approaches more nearly the surface, and often spreads itself on a wide area, producing a dense 
growth of cotton-wood, willows and underbrush, which forced us to ascend and cross the out- 
jutting terraces. The flow of water, however, is not continuous. One or two localities were 
observed where it had entirely disappeared, hut to rise again a few miles distant, clear and 
limpid. 
We thus have along the valley of the San Pedro, with the exception of points which will 
require a little work, ground highly advantageous in every point of view for an emigrant 
road, and most favorable for the location of a railroad, which can he connected with the Valle 
del Sauz by practicable grades, leading through Nugent's pass, in the Calitro mountains, to 
the Playa, and then by easy ascents and descents through the Railroad Pass, to the terminus 
of the first section. But the San Pedro, about twelve miles above its mouth, receives a 
tributary from the Playa de los Pimas basin, and this tributary, the Aravaypa, presents another 
route, connecting the Valle del Sauz and mouth of San Pedro. 
This latter, or Aravaypa route, diverges from the first line near the summit of the Railroad 
Pass, and skirting the bases of the slopes from Mount Graham, enters this new valley and 
follows it to its junction with the San Pedro. 
By the first line, the entire length of this division is 138 miles, and by the second, 108.25 
miles. Starting from the terminus of the first section, in the Valle del Sauz, we have twenty- 
eight miles to the summit of the Railroad Pass, and an altitude of 892.5 feet to overcome, 
giving as an average grade of 16.7 feet for eighteen and three-fourths miles, and of 63.6 feet per 
mile for nine and one-quarter miles. Near the foot of the slope the grade is quite light, and it will 
he increased on nearing the summits, hut will, however, not exceed sixty-four feet per mile. 
Throughout the greater portion of this distance the surface slope can he adopted for the roadway, 
hut on entering the mouth of the Pass there will he some cutting and filling necessary in ascending 
and crossing the drains. The summit is open, broad, and smooth, the ground sloping gently in 
both directions. Looking eastward, a grassy valley trends off to the Sauz, receiving in its course 
many tributaries from the spurs of the Chiricahui and Mount Graham, with smooth side slopes 
and rolling, prairie-like divides. By degrees the valley assumes all the characteristic features 
of a main drain, with a meandering sand bed, and hounded by mesas or terraces, ranging from 
ten to thirty feet in altitude. 
Towards the Playa de los Pimas the same feature is observable, hut on a much smaller scale; 
the drain becoming in its descent more extended, and is finally lost in the plain surrounding 
the Playa 
Leaving the summit, and taking the first of the above routes direct, to the San Pedro, we have 
at first, five miles with a grade of 48.8 feet, which is gradually reduced as w-e descend to the 
Playa, where an almost level (eight feet per mile) stretch of ten miles obtains to the base of the 
slope, extending up to the summit of Nugent’s pass, in the Calitro mountains. This pass, like 
the preceding one, is broad and open, with smooth, rounded hills at its summit, from which a 
continuous plain slopes down to the Playa. Its western approach from the San Pedro, is by a 
small drain, which becomes a decided arroyo , varying from fifty to three hundred yards in 
width, and hounded by terraces from twenty to eighty feet in altitude, with side slopes of 
thirty or forty degrees. 
