AIONTANA (ante), a territory of the United States formed from parts of Idaho and Dakota; pop. '80, 39,157-27,642 oc_ American birth, 3,689 colored, 1737 Chinese, and 1750 Indians and half-breeds. Its surface is rough and mountainous, the main range of tha Rocky mountains entering the iv. portion from the n., and extending 200 in. s.e. in that section; thence changing their direction and trending toward the W. boundary, where they join the Bitter Root mountains. In the e. portion are the Little Rockies, Little Bear, Bear's Paw, Kay-i-you, Gallatin, the Belt range s. of the great falls of the Mis souri, the Highwood in the n., and the low-lying Spoonbill, with many detached spurs and smooth-slooping buttes. This mountainous region constitutes about two-fifths of the surface, extending the entire length,of the territory from n. to s., and for 175 rn. e. of the w. boundary, the general elevation being much less in the n. than in the s. portion. Be'ween these ranges are deep divides ; around the spurs wind beautiful rivers; and pie t,uroscue canons separate the buttes. In the s, portion, in the vicinity of the Yellowstone rive- the mountains rise 11,000 ft. above the level of the sea, wearing it crown of per pettm, and the n. beyond the Missouri, the mountain tops in early autumn are clothe{ blue of the sky, mingled with the purity of the snow, visible for many miles ova 'eve., treeless plains. Away from the strictly mountainous portion there are solitary.,eases of basalt, tuff, and other volcanic rock, of material such that though pre senting a) rocky appearance, or one of great solidity, much of it can easily be cut with a knife. In the crevasses of the mountains, however, may be found green spots bearing nine, cedar and fir trees, and susceptible of cultivation, while the light-brown grass of the plain below, brown by contrast with the vivid green of the moister soil, furnishes nutritious food for the wandering herds marked with the ranchman's brand. A large proportion of its vast territory is taken up by Indian reservations, 24,156.800 acres being held in reserve for them, of which more than 10,000,000 acres are thought to be tillable land, and only 3,769 acres is under cultivation. Immense prairies and bottom-lands,
smooth, rich, and green, await the plowman, unfilled and unhabited. The print of the pony's fleet foot is the only mark on the soil, save the traces of a vanished " tepee," or the high stakes supporting the canvas shelf which holds the rattling bones of a dead Indian in his airy sepulcher.
The territory contains the head-waters of the Missouri, the Clarke's fork of the Columbia river, and the Yellowstone, a tributary of the Missouri, giving its-name to the celebrated national Yellowstone park, which it irrigates and beautifies. These rivers and their branches permeate the entire territory, furnishing natural highways for the transportation of passengers and freight. Of the branches those of the Missouri are all of more or less interest on account of their association with late Indian troubles. The Big Horn, the Rose Bud, whose valley was the scene of Custer's last battle with the Dakotas under Sitting Bull; the Powder, Tongue, etc., flow into the Yellowstone, and the Marias, Milk, Muscleshell, Big Muddy; Jiidith, and Poplar rivers flow directly into the Missouri. The Bitter Root river rises in the w„ flowing n., sometimes in the latter por tion called the Missoula. The Missouri. rising near Gallatin in the s. w., is formed originally of the Jefferson, Madison,1 n 11 anm. Gallatin rivers, and flows me. to Helena, follow ing thence an e. course to Benton and the Dakota line. It is navigable by steamboats from April to September as far as fort Benton, 303 m. from the boundary line of Dakota, and efforts are being made to improve the bed of the stream as far as the falls between fort Benton and Helena. Government appropriations have been made for the building of dikes to keep the water in the channel, and more are confidently expected, as the traffic on the river is assuming weighty proportions. It is a difficult and tedious work, owing to the scarcity of material, The Yellowstone, rising in Yellowstone lake in n.w. Wyoming, is also navigable early in the season, and even so late as A ngnst, as far as the buffalo hunting grounds, 300 in. above its mouth. The Little Missouri crosses the s.e. corner, entering the Missouri in Dakota.