CAÑONS.--The plains east of the Cascade Mountains, through the whole extent of Oregon and California, are covered with a volcanic deposit composed of trap, basalt, and other rocks of the same class. This deposit is cleft by chasms often more than a thousand feet deep, at the bottom of which there usually flows a stream of clear, cold water. This is sometimes the only water to be procured for the distance of many miles; and the traveller may be perishing with thirst while he sees far below him a sparkling stream, from which he is separated by precipices of enormous height and perpendicular descent. To chasms of this nature the name of _cañons_ has been applied, borrowed from the Spaniards of Mexico. We quote Lieut. Abbot's description of the cañon of Des Chutes River, a tributary of the Columbia:-- "Sept. 30.--As it was highly desirable to determine accurately the position and character of the cañon of Des Chutes River, I started this morning with one man to follow down the creek to its mouth, leaving the rest of the party in camp. Having yesterday experienced the inconveniences of travelling in the bottom of a cañon, I concluded to try to-day the northern bluff. It was a dry, barren plain, gravelly, and sometimes sandy, with a few bunches of grass scattered here and there. Tracks of antelopes or deer were numerous. After crossing one small ravine, and riding about five miles from camp, we found ourselves on the edge of the vast cañon of the river, which, far below us, was rushing through a narrow trough of basalt, resembling the Dalles of the Columbia. We estimated the depth of the cañon at a thousand feet. On each side, the precipices were very steep, and marked in many places by horizontal lines of vertical, basaltic columns, fifty or sixty feet in height. The man who was with me rolled a large rock, shaped like a grindstone, and weighing about two hundred pounds, from the summit. It thundered down for at least a quarter of a mile,--now over a vertical precipice, now over a steep mass of detritus, until at length it plunged into the river with a hollow roar, which echoed and re-echoed through the gorge for miles. By ascending a slight hill, I obtained a fine view of the surrounding country. The generally level character of the great basaltic table-land around us was very manifest from this point. Bounded on the west by the Cascade Mountains, the plain extends far towards the south,--a sterile, treeless waste."