CHAPTER IV. 
ROUTE NEAR THE THIRTY-FIFTH PARALLEL OF NORTH LATITUDE. 
The report of Lieut. Whipple upon the route explored by him, near the thirty-fifth parallel 
of latitude, with its accompanying sub-reports, being brief, it is unnecessary to recapitulate the 
details given in them. Some remarks upon the general direction of the route, and upon the 
points which characterize it, and in which it differs from that of the thirty-second parallel, may 
be necessary. 
From the general description that follows, it will be seen that the features of the ground 
which have determined the direction of the route are the extension west and east of the inter- 
locking tributaries of the Mississippi, the Rio Grande, and the Colorado of the West. 
The route may be said to commence at Fort Smith, on the Arkansas, in about longitude 94° 
26/, latitude 35° 23’; elevation above the sea 460 feet; the connexions of which point with 
Little Rock, Memphis, St. Louis, and other centres of trade, are clearly stated. From Little 
Rock to the Antelope Hills, on the Canadian, elevation 2,100 feet, in about longitude 100°, 
a distance of near 400 miles, the route may follow either the valleys of the Arkansas and 
Canadian, or a shorter line, perhaps, but over more broken ground south of the Canadian— 
this latter route branching again and following either the valley of the Washita, or the divid- 
ing ridge between it and the Canadian. 
From the Antelope Hills the route continues along the bottom of the Canadian, on the right 
bank, to the mouth of Tecumcari creek, about 250 miles, and ascends by the valley of Tecum- 
cari, or by that of Pajarito creek, to the dividing ridge between the Canadian and the Pecos 
rivers, elevation about 5,543 feet, and enters the valley of the latter. It follows this valley 
until, by means of a tributary, it rises to the high table-land, or basin, lying east of the 
Rocky mountains, elevation about 7,000 feet, crosses the elevated Salinas basin, 30 miles wide, 
the lowest point being 6,471 feet, and gains the divide in the Rocky mountains, elevation 
about 7,000 feet; from which point it descends to Albuquerque, or Isleta, on the Rio Grande, 
through the San Pedro Pass; or it may descend to the Rio Grande by the valley of the 
Galisteo river, north of Sandia mountain. A third route is indicated along the valley of the 
Pecos to its headwaters ; thence to an affluent of the Galisteo; and thence, as before, to the Rio 
- Grande. 
Isleta, on the Rio Grande, is 854 miles from Fort Smith, and 4,945 feet above the sea. 
Crossing the ridge separating the Rio Grande from the Puerco, the route follows the valley 
of its tributary, the San José, to one of its sources in a pass of the Sierra Madre, called the 
Camino del Obispo. At the summit (elevation 8,250 feet) a tunnel three-fourths of a mile long, 
at an elevation not less than 8,000 feet, is required, when the descent is made to the Zuni river 
and near the Pueblo of Zuni; the route then crosses over undulating ground to the Puerco of 
the West, at the Navajo spring. Another route across the Sierra Madre, about 20 miles further 
north, was examined by Mr. Campbell, which is, apparently, far more favorable. The profile 
is not from reliable instrumental examination. The height of the summit is about 7,750 feet 
above the sea. The Puerco of the West heads in this pass, and the route follows the valley of 
this stream to its junction with the Colorado Chiquito, then the valley of that stream to the 
. foot of the southeastern slopes of the San Francisco mountains, (elevation 4,775 feet ;) distance 
