GEOLOGICAL SURVEY OF THE TERRITORIES. 107 



tional and new methods of obtaining, husbanding, and applying water, 

 as by reservoirs, wells, pumps, elevating machinery, &e., may show that 

 even this estimate is far below the proper figures. 



Efforts already made, and canals uuder way and projected in this 

 division, when completed, will demonstrate the feasibility of bringing 

 under culture a large extent of the lands in these Territories lying east 

 of the mountains. 



In order to avoid repetition and confusion I shall follow out the plan 

 adopted in my last report, using the term " district" to designate the 

 area drained by one of the large streams named, (the Plattes, north and 

 south, being described separately ;) the term " section" being applied to 

 the larger subdivisions of a district. The terms "tillable," "arable," 

 "susceptible of cultivation," not being used as excluding the idea of the 

 future possibility of cultivating other portions, but simply to express 

 the fact that those portions so termed are now sufficiently supplied with 

 water for farming purposes. 



THE RIO GRANDE DISTRICT. 



This district, although chiefly confined within the bounds of New 

 Mexico, penetrates into the southern portion of Colorado. Beginning 

 at Poncho Pass, about 38° 30' north latitude, it extends southward to 

 the southern boundary of the Territory, and is about five hundred miles 

 long. As far south as Santa Ee its width is tolerably uniform, averag- 

 ing very near one hundred miles ; but here it begins to expand rapidly 

 on the eastern side to embrace the area drained by the Pecos, termin- 

 ating in this direction in the Llano Estacado. Excluding the " Staked 

 Plains -" from our calculation, the entire area of this district amounts to 

 about seventy thousand square miles, about five thousand five hundred 

 of which belong to Colorado, (according to the old boundary line.) 



This district may conveniently be divided into three sections, corre- 

 sponding with the natural aspect of the country : First, the San Luis 

 Valley, (sometimes called the San Luis Park,) which constitutes that 

 portion of the district which lies north of the point where the Eio de 

 Taos enters into the Eio Grande ; second, the central portion of the 

 Territory, including the Eio Grande Valley proper and the tributary 

 valleys leading into it between the southern rim of the San Luis Valley 

 and the southern boundary of the Territory ; third, the Pecos Valley, 

 which, beginning east of the mountains, about opposite Santa Ee, runs 

 a little east of south to the Texas line, and includes only the area drained 

 by the Pecos Eiver. 



This district embraces nearly two-thirds of New Mexico, leaving a strip 

 along the western boundary varying from fifty to one hundred miles in 

 width, and drained by the tributaries of the Colorado and Gila Eivers, 

 and a triangular area in the northeast corner drained by the Canadian 

 Eiver. It embraces the central, and, with the exception of a few val- 

 leys, the most productive portion of the Territory; and, although much 

 of it is occupied by broken ranges of mountains and elevated mesas, yet 

 there is a large portion which can be irrigated by the streams that 

 traverse it, and a still larger ratio which affords rich pasturage for sheep 

 and cattle. Here also can be found every variety of climate, from the 

 cold of the mountain region along its northern rim, to the tropical 

 valleys of its southern border. 



SAN LUIS VALLEY. 



This valley, or park, has been correctly described as " an immense 



