deem convenient and proper, or from attaching any portion thereof to any other Territory or State: And provided, further. That, when admitted as a State, the said Territory, or any portion of the same, shall be received into the Union with or without slavery, as their constitution may prescribe at the time of their admission."
Under the old Spanish and Mexican governments, the boundaries of New Mexico were exceedingly indefinite; but this act forever fixes the territorial limits, and also settles the long vexed question of the boundary of Texas.
"New Mexico," says Dr. Wishzenius, in his excellent memoir on the northern part of the Republic; "is a very mountainous country, with a large valley in the middle, running from north to south, and formed by the Rio del Norte or Rio Grande. The valley is generally about twenty miles wide, and bordered on the east and west by mountain chains, continuations of the Rocky Mountains, which have received different names, such as La Sierra Blanca; Los Organos, and Oscura, on the eastern side of the stream; and the Sierra de las Grullas, De Acha, and De los Mimbres, towards the west. The height of these mountains south of Santa Fé, may be averaged between six and eight thousand feet, while near Santa Fé and the more northern regions, some snow covered peaks are seen rising probably ten or twelve thousand feet above the sea. The mountains are principally composed of igneous rocks, as granite, sienite, diorite, and basalt. On the higher mountains excellent pine timber grows; on the lower, cedars and sometimes oak, and in the valley of the Rio Grande, principally mezquite.
The main artery of New Mexico is the Rio del Norte or Rio Grande, the longest and largest river ever possessed by Mexico. Its head waters were explored in 1807 by Captain Pike, between 37° and 38° north latitude; but its highest sources are supposed to be about two degrees further north in the Rocky Mountains, near the head waters of the Arkansas and the Rio Grande or Colorado of the west. Following a general southern direction, it runs through New Mexico—where its principal affluent is the Rio Chamas from the west—and then winds its way in a south-eastern direction, through the States of Chihuahua, Coahuila, Tamaulipas, and Texas, to the Gulf of Mexico in 25° 56' north latitude. Its tributaries in in the latter States are the Pecos, from the north; the Conchos, Salado, Alamo, and San Juan, from the south. The whole course of the river, in a straight line, would be near twelve hundred miles; but from the meandering of its lower half, it runs at least about two thousand miles from the region of eternal snow to the almost tropical
