SOUTHERN PACIFIC LINES 121 
Paso County 65,442 acres, an increase in the two counties of two 
and one-fourth times in 10 years. From McNary northwestward 
the railroad skirts the foot of the steep slope demarking the 
higher terrace. To the southwest are wide areas of irrigated lands, 
and across the river to the south are fine views of the high and pic- 
turesque front of the Sierra del Presidio, in Mexico. It consists 
of strata of Comanche age. A mile west of McNary is the 5,000- 
acre cotton plantation named ‘“‘Algodones” (ahl-go-do’nace, from 
Spanish algodén, cotton), on which most of the water is pumped 
from shallow wells by electric power. 
Among the many frontier military posts established by the Govern- 
ment the garrison at Fort Hancock was regarded as one of the most 
important, for it guarded the San Antonio mail road 
Fort Hancock. through the Rio Grande Valley below El Paso as 
Elevation 3,505 feet. far as Fort Quitman, 20 miles away. The ruins of 
New Osean 3,136 Some of the old buildings are still visible a short dis- 
tance from the tracks about half a mile west of the 
station. 
In this part of the valley the railroad passes along the edge of the 
sand hills at the foot of the terrace that rims the valley. This terrace, 
miles 
° ’ 2 Miles 
a +3 ar 
Cp, Limestone (Permian); Cm, limestone (Pennsylvanian and Mississippian); Sf, Fusselman 
limestone; Om, Montoya limestone; Oe, El] Paso limestone; €b, Bliss sandstone 
which consists of sand and gravel, slopes upward to the foot of the high 
plateau extending northwest from the Finlay Mountains. This 
plateau is capped by the Finlay limestone, dipping to the southeast 
at a very low angle. At one point 8 miles northwest of Fort Hancock 
a butte of shale of Trinity age protrudes through the terrace deposits. 
The wide terraces adjoining the Rio Grande in this region consist 
largely of lake deposits laid down when the river was blocked for a 
period (p. 120) and detritus washed from the ridges to the north. 
Some of the material is loose sand, and in many areas this has been 
blown by the wind into sand dunes. 
Northwestward from Fort Hancock the railroad follows the edge 
of the sand hills past Ross, Iser, and Polvo sidings. Not far west 
are extensive fields of cotton, alfalfa, and other cro ised by 
irrigation, partly by water pumped from the valley fill. ee 
e course of the Rio Grande is very sinuous, and some of the 
larger bends bring it near the railroad. On the opposite side ee 
Mexico are irrigated areas and in places large mountains, which __ 
seem close. There are many cottonwood trees along the valley, 
152109°—33——-9 1 eee 
