72 



LOWER RIO BRAVO. 



country changes. Tlie bed of the river becomes hemmed in by rocky mural banks, the tops of 

 which are beyond the reach of irrigation, and, from the aridity of the climate, they can never 

 be made subservient to the purposes of agriculture. The general formation of the country is 

 limestone^ deposited in strata perfectly horizontal, and where the river has washed its way 

 through the banks, presents the appearance of gigantic walls of dry-laid masonry. The course 

 of the river from this point up to Fort Leaton, near the Presidio del Norte, a distance of 387 



tM 



miles, is almost one continuous canon, utterly unsuited to navigation, and. with a few excep- 

 tions, unsuited for settlement. Occasionally this limestone formation, over 1,000 feet in depth, 

 is broken through and upturned by igneous irruptions from below, forming stupendous moun- 

 tains and gorges of frightful" sublimity. I leave to the officers under my command^ who so 

 bravely surveyed these chasms heretofore untrodden by white men, and probably by Indians, 

 the task of describing in detail this section of the work, which was only visited by me at certain 

 places to determine the latitude and longitude. ' 



My notices have been principally confined to the Texas side of the boundary. Before leaving 

 the mouth of the Rio San Pedro to ascend the Rio Bravo, I will take a rapid view of the country 

 on the Mexican side between this point and the Gulf. The most prominent topographical 

 feature is a chain of lofty mountains of unequal elevation which cross the Rio Bravo about 250 

 miles above Rio San Pedro, and run in a southeasterly direction towards the Gulf. It is com- 

 posed of a variety of ridges, preserving towards each other, and towards the river and th^ 



Gulf coast, a general parallelism. The principal range is called the Sierra Madre. The eastern 

 slope of these mountains forms portions of the States of Coahuila, Nuevo Leon, and Tamaullpas. 

 The area between the Rio Bravo and the bases of these slopes is an arid, cretaceous plain, 

 covered with a spinose growth similar to that on the Texas side. Passing from this plain into 

 the mountains, we encounter a soil made up of the debris of the older rocks, and watered pro- 

 fusely by limpid streams having their sources in the crystalline rocks. And here, in the valleys 

 formed by these mountains, we find large tracts of country within the influence of some irri- 

 gating stream, sheltered from the northers of the winter, and at an elevation above the sea 

 sufficient to overcome the excessive heat of the summer due this parallel of latitude, producing 

 all the fruits of the tropics and the cereals of the more northern climates. The climate ia 

 unsurpassed in salubrity, and nothing is requisite to make this region the garden-spot of the 

 valley of the Eio Bravo but a stable form of government and security from the bands of roaming 

 savages that plunder it at intervals. 



ern portions, as at Parras, the vine is grown with success, and a luscious 

 I, however, will not bear transportation. On the seacoast and southern 

 r at Santa Rosa, oran2:es, limes, &c.. are cultivated successfallv. Some o 



more 



m 



commencm 





the mountains are rich in silver, and at Santa Rosa, as has been elsewhere noticed, the mines 

 were once extensively worked by the Spaniards, and have now passed into the hands of an 

 American company. 



In no civilized country are statistics more difficult to obtain than in Mexico, and several 

 attempts to obtain the population of this region, composing the largest portion of the States 

 of Nuevo Leon, Coahuila, and Tamaulipas, have resulted in such discrepancies as to induce 



me to give credit to none. I have, however, made 



of 



the Rio Bravo on both sides, from the Devil's river down, which I here present. This esti- 



mate 



o 



