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 rido-e forms the divide between the waters of the basin district from those of the Valle 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 ; but, 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 be subdivided into three districts, viz : Ist^ 

 the Cooke's Spring valley or basin, the portion lying cast of the Picacho de los Mimbres and 

 the Florida mountains ; 2d, the valley or basin of the Eio Mimbres, lying immediately west 

 of these mountains ; and 3d, the Pyramid Eidge basin. These valleys or basins are broad and 

 shallow, with scarcely traceable ridge lines, and receive their drainage from the areas extending 

 from the Kio 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 Eidge basin is made up of a system of dry lakes, (playas,) heading or enveloping 

 the northern end of the ridge, and bounded by broad and gentle slopes extending back to the 

 bases of the surrounding mountains. The supply of water through this district is limited, there 

 being but three sources immediately on the present wagon road : Cooke's spring, at the eastern 

 base of the Picacho de los Mimbres ; the Eio 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 Vacca, 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 blufi' terrace ; Agua Fria, a short 

 distance to the southeast from the Ojo de la Vacca ; 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 Eio 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 Eio 

 Grande, at the foot or opening of the gorge between the terminal spurs of the Organ and 

 Mulera mountains, occupied by the Eio Grande for seven miles, extending up to Frontera, 

 the southern limit of an area of bottom land lying along the river, of which that jiortion on 

 the right bank bears the name of Mesilla Valley. 



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 blufl" 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 brid"-e, 

 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 



