GEOLOGICAL SUEVEY OF THE TERRITORIES. 203 



excludes every other growth, giving a very barren appearance to the 

 landscape. 



Besides Taos there are several other villages and settlements, chiefly 

 Mexican, in the southeast part of the valley. The amount of land in 

 cultivation is not more than fifteen thousand acres. Unless the canon 

 through which the Bio Grande emerges into this valley should present 

 some insurmountable difficulty, the greater part of its area may be irri- 

 gated, the northern and western portion from this river, and that part 

 along the mountains from the streams that flow into it. 



The soil is quite different from that of the valleys further north, being 

 very finely pulverized and loose ; it also is of considerable depth and 

 very fertile. The cause of its fertility will be understood from the fol- 

 lowing quotation, made from the preliminary report of the United States 

 Geologist on the " Geological Survey of Colorado and New Mexico," 

 1869, p. 70: 



The valley proper is scooped out of the Santa Fe" marls, which must at one time 

 have prevailed extensively, as in the country north of Santa Fe, hut the surface has 

 heeu smoothed off, so that nowhere are the marls conspicuous ; still they can be seen 

 all along the base of the mountains bordering the valley, where portions of the recent 

 deposits lie high on the mountain side. No sedimentary rocks of older date are seen, 

 aud the Santa Fe marls rest directly on the metamorphic rocks. 



The effect of this marl upon the appearance and character of the soil 

 is plainly seen. The consequence is, that that which in its wild state 

 appears as but a barren sage plain, across which the wind sweeps the 

 fine particles of the light soil, piling it in little heaps around the bushes, 

 by the application of water is changed into a fertile field. And I think 

 Colonel Charles McClure justified in his statement to me, that sufficient 

 wheat to supply the Territory might be raised in this valley. It is con- 

 sidered the best wheat-growing region in New Mexico. The climate 

 appears to be milder here than in the San Luis Valley proper, although 

 but narrowly separated from each other, and the differences of latitude 

 and altitude being slight. 



Having now completed my description of this great mountain basin, 

 it is proper I should refer to the report of Lieutenant E. G. Beckwith, 

 as published in Vol. II, Pacific Bailroad Beports, whose opinion and 

 description differ somewhat from that I have given. He remarks that 

 "in our ride of over a hundred miles from El Sangre de Christo to this 

 place (Taos) we saw no grass in the valleys worth naming, the vegeta- 

 tion being confined almost exclusively to artemisia and a few varieties 

 of cacti, but chiefly the prickly pear ; the pines of the mountains at 

 times extend well down to the plains. In the high small valleys of the 

 mountains the grass is luxuriant and the flowers beautiful." 



There are parts of the open valley which are not well grassed and 

 that have upon them a tolerably thick growth of artemisia, and also 

 some spots grown up with chenopodiaceous shrubs ; but as a whole it 

 may properly be called well grassed. In 1869 our party traveled over 

 exactly the same road here spoken of, camping one night in each of the 

 principal valleys, the Bio Colorado, Bio Costillo, and Culebra, having 

 no difficulty in either in obtaining sufficient grass for our stock. It is 

 true that it was not so rank and abundant in the first two as in the 

 last, which, outside of the cultivated fields, was one rich meadow. The 

 bottoms of the Bio Grande and western slope of the Sah watch basin 

 we found covered with a very heavy growth of grass. 



In summing up his view of this valley, although he calls it one of the 

 finest in New Mexico, yet he goes on to say : 



The extensive valley of San Luis, lying between the Sierra Blanca on the east and 

 Sierra San Juan on the west, and watered by the Rio Graudt del Norte and its uumer- 



