206 GEOLOGICAL SURVEY OF THE TERRITORIES. 



Between this broken region and the Rio de Canado (or Santa Cruz) 

 on the south, lying along the Bio Grande, is a moderate breadth of arable 

 land, some of which is very fertile, and produces not only the hardier 

 cereals, as wheat, oats, and barley, but also corn, which grows large and 

 fine. The tillable area here could be considerably enlarged by irrigation 

 from the Eio Grande, unless there is some impediment which I failed to 

 observe. 



The Eio de Santa F£, Eio Galisteo, and Tuerto Creek afford strips of 

 arable land, varying in width from one to ten miles ; but here also I 

 think the amouut might be increased by proper efforts and more ex- 

 tensive acequias. 



I have not visited the valleys of the Eio de Chama and Eio Puerco. 

 The valley of the Eio Puerco, I understand, is flanked by elevated table 

 lands, and that its lower portion is not supplied with living water but a 

 part of the year ; but its principal tributary, the San Jose, runs through 

 a fine wide valley, in which there is a considerable amount of cultivated 

 land and a number of villages, the breadth available for agricultural 

 purposes being equal to the capacity of the stream. 



The average width of the immediate valley of the Eio Grande, as 

 before stated, has received widely different estimates ; Dr. Wislizenus 

 placing it as high as twenty miles, evidently including the lower terrace 

 which is sometimes present, while Colonel McClure stated to me that he 

 would not estimate it at more than two miles, including only the imme- 

 diate bottoms of the river. Lieutenant Whipple's calculation would 

 give about eight or nine miles as the average, which is probably nearer 

 correct than either of the others. 



The following memoranda in regard to various points along this valley, 

 though not very definite, may be of some interest to the reader. 



At San Domingo it is quite narrow and continues so for about six 

 miles below San Felipe, where it again widens to six or seven miles, the 

 soil being quite sandy. At Bernalillo it is of considerable breadth, but 

 grows narrow in the vicinity of Zandia, again expanding and affording 

 a tolerably broad area at Alameda. From Alameda to a point some 

 distance below Isleta, there is a moderate width of good bottom land. 

 Contracting near Peralto, it widens again in the neighborhood of Tom6 

 with improved soil, the belt continuing with very little interruption 

 to the bend of the Eio Grande, below the mouth of the Puerco, where 

 the bordering hills close in upon it, reducing it to about one mile. At 

 Socorro there is a medium belt, which expands southward, presenting a 

 very fine agricultural section, which is interrupted in the vicinity of Fra 

 Cristobal Mountains. Between San Antonio and Dona Aha are some 

 of the finest portions of the whole valley, opposite which on the east 

 side stretch the saudy wastes of the dreaded Jornada del Muerto. 

 Near Mesilla and Dona Ana are also some fine openings, which are par- 

 tially cultivated. In regard to the few small tributary valleys below 

 the Eio Puerco, I know nothing. 



The volume of water sent down by this river is sufficient to irrigate 

 an immense area of land. At Tome Lieutenant Emory found by meas- 

 urement the entire volume, including two acequias, to be equal to a width 

 of ninety-three feet and depth of two feet, or the area of a transverse 

 section, one hundred and eighty-six square feet. The rate of fall be- 

 tween Peua Blanca and Isleta is nearly six feet to the mile ; it may 

 therefore be possible to carry it to some portions of the higher ground, 

 but in regard to this I am unable to speak positively. Judging from 

 the height of the bluff at San Felipe above the river level, one hundred 



