22 FROM THE PIMAS VILLAGES TO THE EIO GRANDE. 



west by a continuous mesa or terrace, whicli must be ascended by our line, wbetber it leaves 

 the river at either of the above mentioned points, or any intermediate one, the difficulties in 

 each case being about the same. But looking westward of the Kio Grande, along and in the 

 vicinity of this j^roposed line, for sources whence a constant and sufficient supply of water can 

 be drawn for the uses of a railroad, we find the first of any note to be the Rio Mimbres, a 

 mountain brook heading in the rugged region to the northeast of the Copper Mines, and 

 flowing off to the south through canons and valleys which finally open out to the broad plain, 

 where the waters of this stream gradually disappear, and are finally entirely absorbed. This 

 being the most available source of water west of the Rio Grande, our line of road should leave 

 the valley of the latter at that point which gives the shortest interval between it and that point 

 on the plain where the waters of the Mimbres may be made available by conduits or otherwise. 

 In this view of the case, the road should, on crossing the river below Frontera, follow up its 

 valley to near Mesilla, and then make the ascent to the surface of the terrace, where almost an 

 air-line may be located directly to the bed of the Mimbres. Looking, also, to the general 

 question of uniting the waters of the Rio Grande with those of the Gila by the shortest practi- 

 cable route, it will be seen, by referring to the map, that the line just located fills that condi- 

 tion, its course bearing directly for the Railroad Pass due west. 



In the valley bottom we will have an ascending grade of one foot per mile for thirty-six 

 miles, requiring but little earth work, the soil being generally sandy. In many places there 

 will be encountered a light, loose loam, where ballasting will be necessary ; the loam becoming 

 light and miry during the seasons of I'ain. 



Our line now turns westward, and the first question is to ascend the mesa or terrace. This 

 will require comparatively heavy work for a few miles. There are two terraces before reaching 

 the summit of the plateau of the Sierra Madre : one averaging about forty feet above the alluvial 

 bottom of the Rio Grande, west of La Mesilla ; the other, about one and a half miles further 

 west, rises about two hundred and fifty feet above the former, or about four hundred and seven 

 feet above the crossing near Fort Fillmore. This latter steppe sweeps round to the south, and 

 is merged gradually into a plain until it loses almost entirely its terraced character, forming, 

 as it were, an immense amphitheatre, for to the southwest of Fort Fillmore it again assumes 

 the escarped character. By the combined results of the surveys of 1854 and 1855 the summit 

 between the Monument basin and the valley of the Rio Grande has an elevation of six hundred 

 and sixty-two feet above the river, and from this summit the ground slopes about two hundred 

 and eighty-two feet per mile down to the edge of the plateau. To reach the plateau of the 

 Sierra Madre, commencing at a point in the vicinity of San Tomas, and thirty-seven miles above 

 El Molino, we ascend the first terrace by a grade of twenty feet per mile for four miles ; thence 

 to the edge of the plateau five and-one half miles, at the rate of sixty feet per mile; and from 

 this point to the summit, about nine miles, with a grade conforming to the slope of the plain, 

 28.2 feet per mile. 



From this summit to the terminus of the first division, in the Valle de Sauz, a distance of one 

 hundred and thirty-eight and one-half miles, the profile is undulating throughout, and made 

 up of gradients not exceeding 64.4 feet per mile, this maximum being required in crossing the 

 Peloncillo summit. These gradients are generally the surface slopes, and will, of course, involve 

 the necessity of but little earth work in preparing the roadway. Approaching this ridge from 

 the east, on the Boundary Commission road, which leads directly for a gap between a castellated 

 porphyritic protrusion on the right, and a prominent Sugar Loaf (Peloncillo) peak on the left, 

 several favorable depressions are seen on the south of the road, where the continuity of the ridge 



