204 GEOLOGICAL SURVEY OF THE TERRITORIES. 



otis small tributaries, is, in general, one vast sage plain from the Rio Colorado to Gun- 

 nison's Pass. The grass on the lower tributaries of the Rio del Norte, in this valley, is 

 very limited indeed. It is more abundant on the upper affluents, where a few fields 

 of prairie grass a mile or two in width were observed, and the authority of our guide 

 given for extensive grass prairies on the Rio del Norte itself. But all these grass fields, 

 with the greatest amount of cultivation which can be supplied with water from the 

 little streams of this valley, can, under the most favorable circumstances, only support 

 a meager population. 



It is evident from these remarks of Lieutenant Beckwith that he 

 bases his conclusions on his observations and experience in the States 

 where the soil is moistened by- rain, and that he considers the sage 

 ground as unfit for cultivation. But the experiments of the seventeen 

 years which have elapsed since he was there, have taught us that sage 

 land, when irrigated, is about as productive as the grass fields. And the 

 broad sage field that lies west of Fort Garland, (then Fort Massachu- 

 setts,) if redeemed by water, would soon give evidence of this fact. 



I do not refer to the reports of others in any spirit of criticism, but 

 as far as possible to correct the impression made by these opinions, 

 which, though given in all candor, frequently did injustice to this 

 country. 



VALLEY .OP THE RIO GRANDE. 



As I have traveled over but a small portion of this section I cannot 

 enter as minutely into details as I have in regard to the one north of it. 

 My description, therefore, will not only be more general, but made up in 

 part from such reliable information as I could obtain. But this defi- 

 ciency is, to a great degree, compensated by the narrative of Dr. A. 

 Wislizenus, the reconnoissanee of Lieutenant Emory, and the reports of 

 General Pope, Lieutenant Whipple, and others, in which notices of the 

 agriculture and arable lands of different parts of the section are to be 

 found. 



The length from north to south, counting from the mouth of the Bio 

 de Taos to the Mexican line, is about three hundred and fifty miles, 

 with an average width of one hundred and ten miles. It is difficult to esti- 

 mate, even with approximate accuracy, the amount of arable land in this 

 area, as, with the exception of the comparatively narrow valley proper 

 of the Bio Grande, it lies in small irregular valleys and detached spots. 

 And, in addition to this difficulty, great diversity of opinion exists in 

 regard to the average width of this valley, varying from two to twenty 

 miles. Yet this difference is not wholly due to error in either party, as 

 the term " valley ; ' is used in different senses, some meaning thereby only 

 the bottoms immediately along the river, while others include the lower 

 terraces which at some points flank the bottoms. Perhaps the best 

 data we have upon which to base an estimate is to be found in the re- 

 port of Lieutenant Whipple, who, after a careful examination, estimates 

 the cultivable area of a belt thirty miles wide, and one hundred and 

 eighty miles long, east and west — reaching from Anton Ghico to Camp- 

 bell's Pass— at three hundred and sixty square miles, or one-fifteenth of 

 the whole area. As this belt reaches directly across the entire width of 

 the section under consideration, it may be taken as an average of the 

 whole ; for, although it includes the valley of the San Jose on the west, 

 the east end stretches over the broad Mesa de la Vista almost from 

 Anton Chico to San Antonio. This proportion would give for the sec- 

 tion nearly two thousand six hundred square miles of tillable land, which 

 I think may be increased by the proper husbanding of water. 



In order to understand properly the differences in climate and pro- 

 ductions observable in the different parts of this section, it is necessary, 

 not only to take into consideration the latitude, but also the variations 



