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EXTRACTS FROM [PRELIMINARY] REPORT. 25 
descending at an average rate per mile of about thirty-three feet to the lowest point of this basin, 
which drains, it is supposed, into or towards Las Salinas. From this point the San Pedro Pass 
can be approached with a grade of about thirty-five feet per mile. This pass divides the waters 
which flow into the Rio Tuerto from those that flow into, or towards, Las Salinas. About nine 
miles further is another pass or summit, which divides the waters of the Tuerto from those of 
the Rio San Antonio, in the Cafion de Carnuel, with a forty feet cut at the San Pedro summit, and 
a descending grade of about eight feet per mile for seven miles. We pass the second summit with 
only about forty-feet cutting, and thence descend at the rate of about eighty-two feet per mile 
for thirteen miles; thence down the sloping mesa to the Rio Grande, opposite Isleta, at a rate 
of about from twelve to fifteen feet per mile. At Isleta the Rio Grande contracts through a 
comparatively narrow gorge, presenting a most favorable point for crossing. Three spans of 
from one hundred and fifty to two hundred feet will effect this object, there being a bluff on 
both sides favorable for landing, without embankments. 
From Isleta the line continues across the elevated spur which lies between the Rio Grande 
and the Puerco. To attain this summit without excavation, the rock being basalt and lava, a 
grade of fifty-three feet per mile ascending, and of forty feet per mile descending, will be 
required. 
We are now, as it were, at the base of the Sierra Madre, at the mouth of the San José, which 
heads on its summit, affording three points for crossing, viz: one point near the Zuñi road, or 
Camino del Obispo ; the other by the Cañon del Gallo and Zuñi Pass ; and the third by Camp- 
belle Pass, on the Fort Defiance road. The valley of the San José extends uninterruptedly to 
the summit of the mountains, heading in the last named pass with the Rio Puerco of the West. 
This pass lies about due west from Sierra de San Mateo, or Mount Taylor, and is entered by a 
wide and beautiful and apparently level valley, the narrowest point at the summit being about 
three miles. Its northern side is composed of high, red sandstone bluffs, surmounted by escarp- 
ments of yellow sandstone ; the former appears to have assumed every fantastic form in Gothic 
architecture. The south side of the pass is formed by the great spurs of the Zuñi mountains. 
The Zuiii group of the Sierra Madre trends northwesterly from the Camino del Obispo, and 
terminates in this pass. The Rio Puerco of the West heads east of, and turns the point of these 
mountains, and extends southwesterly, with a uniform descent, to its junction with the Colorado 
Chiquito. The average ascent of this valley of the San José from its mouth is about twenty- 
three feet per mile, but the maximum grade, it is believed, will be only about thirty-five feet per 
mile to pass the mountains. A light cut through the loose and gravelly soil at the culminating 
point, and we descend to the Colorado Chiquito, by the Puerco of the West, uninterruptedly, 
at an average descent of thirty feet per mile. 
At a point called the ** Hay Camp,’’ on the San José, this valley divides, one branch heading 
near the Camino del Obispo; and several miles above, another valley, the Cañon del Gallo, 
occurs, which begins in the Zuñi Pass. This latter valley was not explored, but it is much 
lower than the Camino del Obispo, and is represented by intelligent Mexicans and others who 
have passed it as being very favorable for a railroad, presenting no very great obstacle to its 
construction. A trail for pack-mules from Zuñi to the Ojo del Gallo, at the mouth of Cañon 
del Gallo, threads through this gorge. From all I learned and all I saw when in the vicinity | 
of this pass, I am of opinion that a grade of between sixty and seventy feet per mile will suffice 
to cross the mountain at this point; the descent thence to the Pueblo de Zuñi is very gradual. 
The route by the Camino del Obispo is more difficult and will require an ascending grade of 
eighty feet per mile, and & tunnel at the summit of about three-quarters of a mile in length. 
Descending to Zuiii, this route traverses a gently sloping and well-watered valley, with a grade 
not exceeding sixty feet per mile. From Zuñi to the Rio Puerco, at camp No. 74, (Navajoe 
-Spring,) the line passes over the rolling country between Zuñi creek and the Puerco, with 
undulating grades, the maximum not exceeding twenty-five feet per mile, From the mouth of 
