Pasigano river is the most extensive branch of the Colorado, being nearly equal in length to the main stream above its intersection with the former. The Pasigano rises in the Great Prairie, near the western boundary of the province, and interlocks its head branches with those of the Brazos. -Pass ing through the lands of the Comanche Indians, it joins the left side of the Colorado 80 miles above Pecan river, and 354 from Matagorda bay. Entire length 190 miles; general course, southeast.
.dguila river rises in the mountains which form the boundary between Texas and the state of Chi huahua, and flowing through a broken and hilly region, which renders its course exceedingly preci pitous, enters the Colorado 444 miles from Mata gorda bay.
Frio river is the western branch of the Colorado; that from the south, although of less extent, is re garded as the main source of this important river; it heads in a large spring, which issues from the mountains, and forms a stream of considerable magnitude. The distance from the mouth of the Aguila to that of Frio, is 80, and thence to the great spring, 45 miles.
La Baca river, although of limited extent, derives importance from the circumstance of its forming a great part of the western boundary of Austin's co lony, and the eastern limit of De Witt's lands. It rises in north latitude 30°, west longitude 20° 20', and pursues an almost undeviating southeast course, to its discharge into the north arm of Ma tagorda bay. Entire length 130 miles; general course, south-southeast; area drained, 3100 square Guadalupe river has its source in the hills of San Saba, and is here called "Rio Verde," which name it retains until it is intersected by a branch flowing in from the northwest, called " Piedras;" thence it passes nearly due east, 70 miles, to the outlet of the great spring, 8 or 10 miles west of the upper road, where, curving gradually towards the southeast, a farther course of several miles, it enters the Bay of Espiritu Santo, clue south of, and about 16 miles from the mouth of La Baca. The Guadalupe is navigable for small boats to the lower road at Go liad, above which it is very precipitous in its course, affording mill-seats, and abundance of water for ir rigation and other purposes. It drains an area of 13,50(1 square miles, and has an entire length of 287 miles; its general course is southeast.
San Ilnlonio river is a branch of the Guadalupe, but little inferior in magnitude to that river, rises a few miles to the south of the Rio Verde, and pur sues a rapid course towards the southeast, under the name of Medina river, to its confluence with the San Antonio proper, 20 miles southeast of the town of Bexar. Continuing its southeastern course, the San Antonio unites with the Guadalupe about 10 miles from its mouth. It is navigable for boats
of small draft to the lower road, but above that point it becomes rapid, and its course much ob structed by falls and cascades, which, while they serve to enrich the landscape, render the stream entirely unfit for navigation. Entire length 275 miles; general course, eastsoutheast.
.dransaso river is a small stream, about 60 miles in length; it is formed by several branches, which rise north of the road leading from Laredo to Go liad, pursues an eastern course, and passing the missionary station of Refugio, enters Aransaso bay.
Nueces river, the boundary between the province of Texas and state of Tamaulipas, has its sources interlocking with those of the Colorado, the first fountain of that river being but a few miles north of the springs from which the Nueces issues, in north latitude 29° 45', and west longitude 30'. From its principal source in the mountains of San Saba, the Nueces flows nearly south-southeast 60 miles, and then gradually turns towards the south east, which course it continues to flow until it enters the Gulf of Mexico, in north latitude 30'. Its entire length is 300 miles, and it drains an area of 12,200 square miles.
Rio Frio, the principal branch of the Nueces, heads near the source of that river, and running a southeastern course, enters the left side of the Nue ces, 110 miles from the Gulf. Ascending the Rio Frio, the following streams successively present themselves: Puenta de la Piedra 3, Saparita 8, and San Miguel 18 miles above the mouth of Rio Frio. It was near the source of the Saparita, and a few miles south of the town of Bexar, that general To ledo was defeated in 1813. In Texas, although its geological structure, so far as it is known, would naturally lead us to expect interior lakes; yet, with the exception of Saline lake, none of any magnitude have yet been discovered within the borders of the province. Between the Nueces and Rio Bravo, in the state of Tamaulipas, a succession of salt lakes have been discovered. These lakes, although not belonging strictly to the country immediately tinder review, deserve particular notice, as they have since their discovery yielded, and will, no doubt, long continue to afford an ample supply of salt, not only for the country in their vicinity, but also for the consumption of the southwestern quarter of Texas. The salt lakes of Tamaulipas are situated about 30 miles northeast from Mier, a town of Tamaulipas on the Bravo. " The salt in these lakes," says Col. Austin, " crystallizes at the bottom in strata from four to six inches in thickness." Large quantities of salt are annually taken from them without pro ducing any serious diminution. There are three large and several small lakes, altogether covering an area of 100 square miles.