The most notable of the great _plateaux_ of the Prairies is that known to Mexicans as _El Llano Estacado_, which is bounded on the north by the Canadian river--extends east about to the United States boundary, including the heads of the False Washita and other branches of Red River--and spreads southward to the sources of Trinity, Brazos and Colorado rivers, and westward to Rio Pecos. It is quite an elevated and generally a level plain, without important hills or ridges, unless we distinguish as such the craggy breaks of the streams which border and pierce it. It embraces an area of about 30,000 square miles, most of which is without water during three-fourths of the year; while a large proportion of its few perennial streams are too brackish to drink of. I have been assured by Mexican hunters and Indians, that, from Santa Fé southeastward, there is but one route upon which this plain can be safely traversed during the dry season; and even some of the watering-places on this are at intervals of fifty to eighty miles, and hard to find. [Pg240] Hence the Mexican traders and hunters, that they might not lose their way and perish from thirst, once staked out this route across the plain, it is said; whence it has received the name of _El Llano Estacado_, or the Staked Plain. {182} In some places the brows of these _mesas_ approach the very borders of the streams. When this occurs on both sides, it leaves deep chasms or ravines between, called by the Mexicans _cañones_, and which abound in the vicinity of the mountains. The Canadian river flows through one of the most remarkable of these cañones for a distance of more than fifty miles--extending from the road of the Missouri caravans downward--throughout the whole extent of which the gorge is utterly impassable for wagons, and almost so for animals. Intersecting the direct route from Missouri, this cañon was a source of great annoyance to some of the pioneers in the Santa Fé trade. In 1825, a caravan with a number of wagons reached it about five miles below the present ford. The party was carelessly moving along, without suspecting even a ravine at hand, as the bordering plains were exceedingly level, and the opposite margins of equal height, when suddenly they found themselves upon the very brink of an immense precipice, several hundred yards deep, and almost perpendicular on both sides of the river. At the bottom of those cliffs, there was, as is usually the case, a very narrow but fertile valley, through which the river wound its way, sometimes touching the one bluff and sometimes the other.