In the northern part of the territory the Bitter-root, Kootenay, emir d'Alene, and Clearwater mountains may be considered as spurs of the Rocky mountain range, while the Bear river ranges in the s.e, part of the territory form connecting links between the main continental divide and the Wasatch.range. The summits of the Sal mon river mountains, and those of the n.w. part of the territory, range from 10,000 to 13,000 ft. above the sea; those of the s.e. are somewhat lower. The most remarkable feature of Idaho connected with its mountain system is the vast lava bed which covers the whole of the territory on the s.e. and s. along the course of the Snake river; forming a desert 400 in. long, mostly on the n. side of the river, varying in width from 40 to 60 m., and exhibiting over a consider able part of that area the black and ragged character of a recent volcanic eruption. It is the eastern end of a vast volcanic belt extending westerly to the Pacific; and of the same character as the lava beds in which caps. Jack with his Indian warriors long evaded the U. S. troops in California. The volcanic craters from which all this sea of lava has been poured out arc plainly indicated by the planes of the flows, though the craters themselves are generally inconspicuous among the mountains that bound the lava on the north. W.n.w from fort 'hill and Blackfoot station, on the Utah and Northern railway, are the Three Buttes, known since the first migration to the Pacific coast as landmarks on the great emigrant route which traversed this lava field near them to reach the foot-hills of the Salmon river mountains. These buttes rise, isolated, out of the lava plain, and have been volcanoes. The middle one, however, was last to spread its molten streams on every side, as proved by the descending planes of lava. It is probable that the whole northerly side of this volcanic belt was dotted with craters when the lava deposit took place, but they are now recog nizable in a few places only, where last in action filter covering the great plain the lava flowed backward into the mouths of the valleys between the foot-bills on the n., so that nearly all the streams that how e. and s.e. are dammed by the lava, and sink into its porous masses, flowing under it, to reappear after a suhtcrranean passage from 30 to 50 m. as springs and cascades issuing from the basaltic walls of Snake river. The most rugged portion of this desert lies near the foot-hills on its northern edge. On the line of its back-flow to these hills, and up their valleys, the old emigrant road was forced to make its tortuous windings to avoid the rough lava. The lower portions of the plain nearer the Snake river, either by reason of greater age and disintegration, or by alluvial deposits upon it, are covered with soil upon which the sage-brush flourishes, and which needs only irrigation to be productive of whatever crops its eleva tion above the sea will permit.
Snake or Shoshone river, or Lewis fork of the Columbia. with its branches, drains all the territory except the far n. and the s.e. portions. The Bear river, which flows into Great Salt lake, drains and waters a portion of the territory that admits of considerable agricultural development. The Snake rises in the main Rocky moun tain range, in Wyoming, entering Idaho on a n.e. course, then comes to the s. and by an irregular semicircle flows s.w., w., n. w., and n., where it divides the territory from Oregon; and thence turns westward to join the Columbia. Steamers ascend from its mouth to Lewiston, and it is navigable also from the mouth of Powder river to Salmon falls, a distance of 200 miles. It traverses a course of 850 in. in Idaho alone. Its chief tributaries from the n. side, in the territory, are the Clearwater, the Salmon, the Weiser, the Payette, the Boise, and the Malade or Wood rivers; from the s. the
Owyhee river, and a large number of smaller streams. The river from its entrance into the territory down to the, falls at its southern curve is generally deep, narrow, and rapid, and can be used to irrigate large areas of adjacent lands now desert for lack of water. Below the falls it cuts deep through beds of lava and rock. Three falls in the river deserve notice. The American falls have is perpendicular descent of 60 or 70 feet. The Shoshone falls are inferior only to those of the Niagara and the Yosemite. The river here is 600 ft. wide. Above the falls it is divided by five islands into six parts, and then, after flowing 400 yards further, it passes in an unbroken sheet over a preci pice, making a perpendicular descent of 200 feet. At some seasons of the year the body of water is almost equal to that at Niagara. The surrounding scenery is magnifi cent. The Sahnoil falls, 45 m. below the Shoshone, are 20 ft. high. There are numer ous other waterfalls in the territory, some of which are of greater height than those above named; though the body of water is smaller. The valleys of the tributary Streams are from 3,000 to 6,000 ft. above the sea, and some of them are from 10 to 15 m. wide. The Salmon river drains is large part of the central mountains of Idaho, and flows from its source s. of lat. 44, first n.n.w., then turns due e., where it receives the Yankee fork, a small stream recently made famous by great mines, and after flowing about 50 m. e., runs n. and finally w. to the Snake. Its head-streams are numerous, and formed directly from the snows of lofty mountain ranges, so that the river is a con siderable stream near its source, there flowing through a valley of rare beauty, though too elevated to have value as grazing or agricultural land. At every part of its course it is fed by mountain streams. The Boise river is made by the junction of the North, Middle, and South forks, which flow s.w. from the Saw-tooth range of the Salmon river mountains and drop down from their sources to valleys of lower level than those of other parts of the territory; so that the s.w, part of the territory and the valley of the Boise river are the warmest, and most varied in agricultural products. Fruits and vegetables of all kinds grown in the northern states flourish there. The Weiser and Payette rivers are chiefly noted for having been the theater of some of the most success ful gold placer diggings ever known. The Wood river, known where it enters the Snake as the Malade, flows southerly from sources in. lat. in the Salmon-river ,nouutains. Where it issues from thu bn the aorthern edge of tile lava plain its detritus widens into a plain of 20,000 or more acres 5,700 ft. above the sea, which the river might be made to irrigate. The river above this descends through a nar row valley by an easy plane from its source in the pass at the head of the Salmon river. The Lendmi, time most easterly tributary of the Sahnon, joins it at Salmon city, and is fed by short streams directly from the main divide of the Rocky mountains. The Clearwater is the main stream in the northern part of the territory, also known for its gold-washings. Three long narrow lakes furnish a peculiar navigation for the extreme northern part of the territory, These are the Coeur d'Alene, about 18 m. long and 2 In. wide, emptying by the Spokane river into the Columbia; lake Pend d'Oredles, really a wide part of Clarke's fork of the Columbia river, about 30 m. long and 2 to 6 in. wide; and lake Kamsku, flowing into Clarke's fork from the mouth. These lakes are bordered by a country rich in timber, especially a large growth of red cedar.