OCR Text |
Show composed of valley, plateau, and mountain section in wonderful variety, portions of which have been laid out into the following political divisions: California, Nevada, Utah, Wyoming, Colorado, New Mexico, and Arizona; and prior to its exit into the Gulf of California it washes the eastern shore of Lower California and the western shore of part of Northwestern Mexico. The length of the river from the junction of the Grand and Green is approximately 875 miles. Its elevation afc Hanlon's Ferry, near Fort Yuma is 120 feet; at the grand bend to the south, near head of Black Canon, 900 feet; at the junction of the Green and Grand rivers, 3,860 feet, from whence the name Colorado begins. It is essentially a canon river until it leaves the territory of the United States, when its character in this regard materially changes, and with it the peculiarities of erosion and alluvial depositions in vicinity of its shifting bed, while opportunities for diverting the same are more likely to be found. The climate along its banks varies partly with the elevation, but more largely with the amounts of rainfall, which, until reaching the Grand Canon, may be said to vary from £ to 10 inches annually. In portions near the sources of Grand Eiver, in the high, mountainous regions of Colorado, the rainfall increases somewhat in proportion to the altitude, and without any specific data on the subject it is safe to say that it reaches 40, if not a larger number of inches annually; but the areas showing the larger amounts of precipitation are comparatively small, and confined to the narrow valleys of the main stream and their side branches within the mountainous portions proper. No such amount of rainfall is known in any part of the Green Eiver Basin, even at its source. Very little of this valley is available for agricultural purposes, and it would be difficult to improve large tracts of land along the main stream or any of its immediate tributaries. The districts, then, into which the entire valley- drainage of the Colorado area may be divided are as follows: First, the more desert parts, bounded on the east by the western mesa wall of the Lower Grand Canon, which is limited in extent on the north by the rim of the great interior basin near the Nevada and Utah line, and extending southward by the heads of the Salt and Gila rivers to the continental divide. Within this area there are strips of considerable size not desert, but diversified between mountain and desert, the northern portions of which, especially in the vicinity of the Salt and Gila rivers, are susceptible of cultivation, forming some of the finest grazing^ elds in the world, with large patches of pine and other timber, and admitting of considerable settlement. Bidges traverse these portions, those running north and south being usually mineral- bearing, that have been prospected, but can scarcely be said to have been worked for the precious minerals. The next is the plateau and caiion district, which has been delineated along its western line in the earlier reports and maps of the survey, the eastern limit running along the continental divide north as far as latitude 37°; from that point to the mouth of the Green and Grand rivers, thence in a nearly due west line to the great mesa- wall, passing northward of the Lower Grand Gaiion, with an arm of the great interior basin in the vicinity of latitude 38° and longitude 113°, approximately. The third portion is the province of the mountains, with their outlying foot- hills, being the basins, respectively, of the Green and Grand rivers, whose peculiarities have been noted by earlier explorers, and are being examined from time to time by Government parties. The first or desert province is approximately 72,889 square miles; the |