generally the Rio Gila is considered to form it. Towards the west of New Mexico an immense country is spread out between the Rio Colorado and the Gila, inhabited only by wild Indian tribes. This whole wide country is sometimes allotted in the Mexican maps to Sonora, sometimes to Upper California, but generally to New Mexico, while the large waste desert northwest of the Colorado is generally attributed to California.
If we accept now in all directions the widest boundaries for New Mexico, it would extend from 32° 30′ to 42° north latitude, and from 100° to about 114° longitude west of Greenwich. But as the country of the wild Indians has never been under any jurisdiction or control of the Mexicans, and settlements have never extended over the whole territory, the name of New Mexico has generally been applied only to the settled country between the 32° and 38° latitude north, and from about 104° to 108° longitude west of Greenwich. In this limited extent, whose lines are drawn by custom, gradual development, and natural connexion, it will be most convenient at present to consider New Mexico.
New Mexico is a very mountainous country, with a large valley in the middle, running from north to south, and formed by the Rio del Norte. The valley is generally about 20 miles wide, and bordered on the east and west by mountain chains, continuations of the Rocky mountains, which have received here different names, as Sierra blanca, de los Organos, oscura, on the eastern side, and Sierra de los Grullas, de Acha, de los Mimbres, towards the west. The height of these mountains south of Santa Fe may, upon an average, be between six and eight thousand feet, while near Santa Fe, and in the more northern regions, some snow covered peaks are seen that may rise from 10,000 to 12,000 feet above the sea. The mountains are principally composed of igneous rocks, as granite, sienite, diorit, basalt, &c., On the higher mountains excellent pine timber grows; on the lower, cedars, and sometimes oak; in the valley of the Rio Grande, mezquite.
The main artery of New Mexico is the Rio del Norte, the longest and largest river in Mexico. Its headwaters were explored in 1807 by Captain Pike, between the 37° and 38° north latitude; but its highest sources are supposed to be about two degrees farther north in the Rocky mountains, near the headwaters of the Arkansas and the Rio Grande, (of the Colorado of the west.) Following a generally southern direction, it runs through New Mexico, where its principal affluent is the Rio Chamas from the west, and winds its way then in a southeastern direction through the States of Chihuahua, Coahuila and Tamaulipas, to the gulf of Mexico, in 25° 56′ north latitude. Its tributaries in the latter States are the Pecos, from the north; the Conchos, Salaclo, Alamo, and San Juan, from the south. The whole course of the river, in a straight line, would be near 1,200 miles; but by the meandering of its lower half, it runs at least about 2,000 miles from the region of eternal snow to the almost tropical climate of the gulf. The elevation of the river above the sea near Albuquerque, in New Mexico, is about 4,800 feet; in el Paso del Norte about 3,800; and at Reynosa, between three and four hundred miles from its mouth, about 170 feet. The fall of its water appeared to be, between Albuquerque and el Paso, from two to three feet in a mile, and below Reynosa one foot in two miles. The fall of the river is seldom used as motive power, except for some flour mills, which are oftener worked by mules than by water. The principal advantage which is at present derived from the river is for agriculture, by their well managed system of irrigation. As to its navigation
