FROM RIO GRANDE TO VALLE DEL SAUZ. 
21 
also a low chain of conical hills, Pyramid ridge, which is turned at its northern end by this line 
of survey. Near the western limit of this division is found a continuous ridge of uniform 
masses and sharp peaks, the most prominent of which has been styled El Peloncillo (sugar-loaf.) 
This ridge forms the divide between the waters of the basin district from those of the Yalle del 
Sauz, which flow towards the Gila. Besides these several prominent features, there are others 
less striking and secondary in their character. The Picacho of Mesilla, a sharp, conical peak, 
situated on the margin of the mesa , a short distance above the town of the same name. To the 
west of this, and north of the line, are several low terraces, whose surfaces are generally covered 
with a flow of basaltic lava ; hut, when this has been removed, they are broken up into rounded 
knobs. These knobs are found completely isolated on the plain south of the wagon road and 
beyond the Mimbres. The plain or table land may he subdivided into three districts, viz : 1st, 
the Cooke’s Spring valley or basin, the portion lying east of the Picacho de los Mimbres and 
the Florida mountains ; 2d, the valley or basin of the Bio Mimbres, lying immediately west 
of these mountains ; and 3d, the Pyramid Bidge basin. These valleys or basins are broad and 
shallow, with scarcely traceable ridge lines, and receive their drainage from the areas extending 
from the Bio Grande divide to the Peloncillo ridge. The valleys are parallel to the trend of 
the mountains, and have a gentle slope southwards, probably centering in the Lake Guzman 
basin, and give to the line which traverses them at right angles an undulating profile. 
The Pyramid Bidge basin is made up of a system of dry lakes, ( playas ,) heading or enveloping 
the northern end of the ridge, and hounded by broad and gentle slopes extending hack to the 
bases of the surrounding mountains. The supply of water through this district is limited, there 
being hut three sources immediately on the present wagon road: Cooke’s spring, at the eastern 
base of the Picacho de los Mimbres ; the Bio Mimbres, a clear, rippling trout-brook, coming 
from the Copper Mine mountains, and losing its waters in the plain to the west of the Picacho ; 
the Ojo de la Yacca, a spring rising in the plain about seventeen miles further to the west. Besides 
these sources there are three other springs, but of minor importance: Neide’s spring, about fourteen 
miles to the southeast of Cooke’s spring, at the point of the bluff terrace ; Agua Fria, a short 
distance to the southeast from the Ojo de la Yacca ; and the Ojo de Inez, a spring rising in a 
canon of the Burro mountains, about six miles to the north of the wagon road. 
Taking the central section in connexion with the eastern section of the 32d parallel route, 
its initial point on the Bio Grande will be taken to correspond with the terminal point of that 
survey—Molino, two miles above El Paso. Molino is situated on the left bank of the Bio 
Grande, at the foot or opening of the gorge between the terminal spurs of the Organ and 
Mulera mountains, occupied by the Bio Grande for seven miles, extending up to Frontera, 
the southern limit of an area of bottom land lying along the river, of which that portion on 
the right hank bears the name of Mesilla Yalley. 
In this gorge there are many favorable localities for bridging the river; but, in order to have 
both abutments upon our own soil, it will be necessary to ascend the river about half a mile 
above the initial point of our new southern boundary with Mexico. 
Between this point and Frontera, the foot slopes of the mountains on both sides bluff down 
in many places to the water’s edge, presenting advantages for bridging nowhere found be¬ 
tween Frontera and Dona Ana. The selection of a site will depend upon a detailed survey of 
the approaches and the line to be pursued on leaving the crossing. Starting from the bridge, 
the location of a road will depend solely upon the consideration of the supply of water 
to be had along this line. From Frontera to Mesilla, the bottom land is bounded on the 
