WYOMING (ante) was organized as a territory in 1868 from areas previously in Dakota, Idaho, and Utah, but derived more remotely from the original territories of Nebraska, Utah, and Oregon, a portion having at one time belonged also to Washington territory. The main chain of the Rocky mountains extends across it s.e. and n.w., entering from Colorado w. of the 105th meridian, and passing out at the n.w. corner. Of these mountains, the principal ranges are the Wind river mountains in the n.w.; the Big Horn mountains, n. of the center; the Black hills in the n.e.; the Laramie mount ains, s.w. of these; the Bishop mountains w. of the main chain; and the Rattlesnake hills and Sweetwater mountains, in the central portion of the territory, the former n. and the latter on both sides of the Sweetwater river. The Laramie mountains form the eastern boundary of what is known as the Laramie plains, a cold and elevated region, whose surface varies in character and elevation, some portions consisting of meadow expanses and others rolling and hilly, with very little vegetation. The most notable topographical feature of Wyoming, however, is the valley of the Yellowstone in the n.w. corner, in which an area of 3,525 sq.m. has been reserved as a national park. Here may be found the largest and most numerous geysers (or spouting, intermittent thermal springs) in the world. About 50 of them throw columns of water 200 ft. high; in all they number nearly 10,000, and they deposit chiefly lime and silica. The temperature of the calcareous springs is from 160° to 170°, that of the others rising to 200° or more. i Other objects of interest are the caflons of the Yellowstone river, and the mountain ranges that hem in the valley on every side, rising here and there to 10.000' and 12,000 ft., and always covered with snow. The Yellowstone and its tributaries, the Big Horn, the Tongue, Powder, Little Missouri, and Cheyenne, drain this portion of the territory and the n. and n.e. ; Green river and its tributaries traverse the s.tv. section; and the ii.
fork of the Platte, with its tributaries, and a few of the smaller affluents of the s. fork, drain nearly all the rest. The geology of the territory embraces in the mountain ranges Devonian, carboniferous, triassic, Jurassic, and cretaceous rocks, succeeding each other in regular order; while the elevated plains are mostly cretaceous, overlaid with tertiary sands, gravel, and drift, with occasional extensive deposits of lignite or brown coal. These coal-beds contain from 50 to 54 per cent of fixed carbon, and are extensively worked. i orked. Gold is found and mined in the Sweetwater region, and also in the Black hills, and in two or three other ranges in small quantities. Extensive iron deposits are known to exist, but have not yet been developed; and there are profitable mines of cop per, lead, and gypsum. The arable lands, it is believed, embrace 5,000,000 acres, and those available for grazing purposes about 35,000,000. The mountains are covered with a thick growth of pine, spruce, and hemlock trees of large size; the foot-hills have pine, spruce, aspen, walnut, elm, ash, box, elder, and red cedar; and the river-bottoms are abundantly supplied with two species of cottonwood and thickets of willows. The wild animals are principally the grizzly bear, black bear, wolf, prairie wolf, badger, wolverine, otter, porcupine, mink, skunk, little ermine, buffalo, elk, deer, antelope, and prairie-dogs. The climate varies with the altitude, being severe on the higher mount ains, and comparatively mild in the sheltered valleys. The average mean temperature of the year is, for the whole territory, about 44°. In the mountains it is, in some years, as low as 36°, while on the plains in the e. it averages 45°. The summers are usually cool, though sometimes the temperature for a day or two rises to 100°. The rainfall is small, varying from 8 to 13 in.; but in all the arable portions there are streams flowing at such an elevation that irrigation is not difficult.