ROCKY MOUNTAINS (ante). Explorations and surveys of the vast extent of elevated plateaus, and the many separate ranges of this mountain system, have been made by the U. S. government with exceeding thoroughness. Colorado, Wyoming, New Mexico, and Utah, with the portion of the range which traverses them, have nearly complete scientific surveys, including their topographical and geologic features. The parts of the range in Idaho, Montana, Wyoming, Oregon, and Washington territories. are less advanced in their surveys, which are still in progress. The first comprehensive exploration of this central part of the continent was made by eapts. Lewis and Clarke in 1803-6 under the direction of president Jefferson, in connect-ion with their explora tion of the upper Missouri and the Columbia rivers. Maj. Z. M. Pike in 1805-7 trav ersed the plains to Pike's peak (named after him), discovered the head-waters of the Arkansas in the heart of the range in Colorado, and crossed into the great basin on the w. side of the range. In 1819-23 col. S. II. Long was sent with a party to make a. scientific survey of the same region; the peak n.w. of Denver was named in his honor. The real first explorers of all the great interior parts of the continent were the hunters and trappers employed by the British and American fur companies, the latter operating from St. Louis. The most extensive explorations by any one scientific party, however, were made in the three expeditions led by col. John C. Fremont under government. authority. The first in the winter of 1842-4,3 made a survey of the South pass and dis covered the Wind River mountains, the highest peak of which Fremont ascended and measured, and it received his name. The second expedition started in May, 1843, and explored the route by Bridger's pass over the mountains, located the Great Basin of Salt lake, and crossed to the Columbia river, returning by the way of the Great Basin. In 1846 gen. P. Kearney traversed the Rocky mountains with a military party to Cali fornia, and returned overland in 1847. Fremont's last explorations were in 1848 up the Rio Grande from Santa Fe and thence across the great chain w. to the Great Basin. In 1853 the government ordered extensive surveys in the Rocky mountain country, the results of which are contained in 13 vols. of maps and reports. These were the bases of the support given by the government to the construction of the Union Pacific railway 1866-70. The U. S. scientific surveys completed and in progress, under the direction of prof. Hayden, I. W. Powell, Clarence King, and other able scientists, will be almost unequaled in their completeness. The search for the precious metals also fills the region with an advance corps of unscientific explorers.
The vastness of area of the Rocky mountains, their erratic and widely separated ranges, spurs, and groups of mountains, and the extent of the great plateaus at high elevations, impress the mind far more than their picturesqucnees or scenic character. The Andes in South America form a much loftier and narrower chain. Persons famil iar with them, or with the Alps, find the scenery of the Rocky mountains relatively Same. Travelers by the Union Pacific railway which gains the first continental divide: at Bridger's "pass," at an altitude of 7,000 ft., are astonished to see a broad gravelly plain stretching away on all sides, and the mountains forming the horizon apparently of no great height. Rising from a base of plains 4,000 to 6,000 ft. above the sea, the mountains only begin at those levels.
The Rocky mountains are the summit divide of North America, and a continuation of the chain of the Andes of South America. At the isthmus of Darien, sinking to a. minimum elevation of 100 ft. above the sea, they increase in height northward through Central America, where their well-watered summits, on the Pacific side in Costa Rica, have the most delightful of climates. In Guatemala they rise into the volcanic elevations. of Fuego and Agua, 13,000 and 14,000 ft. high respectively ; and thence into Mexico,w here, in lat. 19', the chain is 300 m. wide and rises into the loftiest elevations of the continent, in a chain of mountains running e. and w., forming the volcanoes of Popocatepetl, 17, 540 ft. ; Orizaba, 17,176 ft.; Toluca, 16,610 ft.; and Iztaccihnatl, 15,705 feet. North of this loftiest part, between the eastern and the western declivities of the great mountain mass, is the plateau of Mexico, a comparatively level plain from 3,000 to 6,000 ft. above the sea (averaging 5,000 ft.) extending from the city of Mexico 1200 m. northerly to the United States line, of a width varying from 200 to 500 miles. See MExico. The! highest part, or main chain, where it miters tht United States from western Chihuahua, is known as the Sierra Madre, and is there 180 m. in breadth, of purely mountain country, the highest parts of which are about 8,000 ft. above the sea. The eastern slopes are well-watered and fertile. Cotton and the grape are grown ou the lower parts. The Sierra Madre mountains spread into a number of ranges in Arizona, difficult to classify; nowhere rising into mountains of so great height as in southern Mexico or Colorado, and forming elevated plateaus of a more irregular char-. acter than those of Mexico. The easterly side of the chain where it enters New Mexico has an altitude of from 6,000 to 8,000 ft., increasing northwardly to the Colorado line, near the source of the Rio Grande, where many peaks rise to 14,000 feet. Through Colorado the range maintains a grand elevation. Here the U. S. surveys have been. most elaborate, and the attaution given to the country by the discoveries of great num bers of mines, and ready access afforded by railways, have made this state the most noted for the study of the mountains. See COLORADO. The streams which flow c. to the
and s.w. to the gulf of California rise in snow-covered ranges inclosing a system of " parks" which have given the name of " the park system" to this part of the Rocky mountains. It is bounded n. by the Laramie plain, e. by the great plains, w. by the canon-rifted plateaus of the Colorado, and on the s. merges into the ,valley of the upper Rio Grande. North park is the basin of the head streams of the North fork of the Platte; Middle park is the basin of the sources of Blue river (the North fork of Grand river) flowing to the Colorado; South park is the basin of the springs of the South Platte, and one of the head streams of the Arkansas; and San Luis park the basin at the source of the Rio Grande. All these parks lie at elevations from 5.000 to 7,000 ft. above the sea, and gather the drainage of the snowy ranges to carry them to the gulf of Mexico on the e. and the gulf of California on the west. For geologic and topo graphical surveys of this region see COLORADO and NEW MEXICO. The easterly range m view from Denver is called the Colorado range; its continuation n. forms the Medicine Bow range; w. of the Middle and North parks is the Park range. The Colorado range by a westward trend connects at mount Lincoln with the Park range, and divides. North park from Middle park. The Park range, which lies nearest to the great pla teaus of the head-waters of the Colorado w. of Middle park, becomes a middle range fur ther s., and lies e. of the upper valley of the Arkansas. A third range, having its n. head in the mountain of the Holy Cross, becomes the westerly range. Its n. parts take the name Sawatch range, and the southern the San Juan range. It has more elevations. reaching to 14,000 ft. than any other part of the Rocky mountains in the United States. South of the Sawatch range the country is broken into great mountain masses too isolated to suggest a range. The Pike's peak group is the most north-easterly group of this char acter. The following table gives the altitudes of the main elevations of these ranges: North of Colorado and on the line of the Union Pacific railway, there is a relatively low part of the great chain, which was formerly known by the names of its lowest points, as South pass, Bridger's pass, etc. The Union Pacific railway took the latter. The Black hills arc the most easterly outlying spur of the range n. of these passes. The main chain trends n.w., and spreads over an area 300 m. wide in Wyoming; its easterly ranges in the w. part of that territory taking the names Big Horn mountains and Wind River mountains. The greatest elevation and some of the most picturesque parts of the range are at the Three Tetons, near the w. line of Wyoming, s, of the National park at the head of the Yellowstone. See NATIONAL PARK OF TILE YELLOWSTONE. On the n. side of the Snake river, in Idaho, the range develops a volcanic character up to recent times. Isolated and exceedingly irregular and lofty uplifts fill die whole of cen tral Idaho, and nearly all of Montana. (Sec those territories.) South of the great val ley through which the Union Pacific railway is laid there are the lofty and isolated ranges named Walisatch and Uinta. The former is the most abrupt elevation on the eastern border of the great basin. Its western slopes drain into the Jordan river and Great Salt lake, and its eastern slopes into the Colorado. Its greatest elevations, Twiu. peaks, Lone peak, and mount Nebo, are about 12,000 ft. above the sea, and as their summits are not more than 20 m. from the valley of the Jordan, 4,500 ft. above the sea, they form a peculiar group which arrests and attracts the moisture from the air currents of those regions and concentrates upon their heads an amount of snow-fall in the winter greater than upon any other part of the Rocky mountain in the United States. Near the sources of the streams that empty into the Jordan the avalanches and snow-slides are more frequent and dangerous thau elsewhere. The Uinta mountains is a range or mountain mass connecting the Wahsatch with the main ranges east.
North of the United States the range is supposed to have an equal breadth of rami fication, and its elevations are greater. Mounts Hooker and Brown, 300 m. n w. of Idaho, have an altitude of 15,700 and 16,000 ft. respectively. The range is thence north ward continuously lofty, and forms the westerly wall of Mackenzie's river, flowing in to the Arctic sea, but is pierced in several places by streams rising w. of the range, and empty ing dither into that river or into streams that flow into Hudson's bay.
Some authors name all the mountains between the basin of the Mississippi and the Pacific as portions of the Rocky mountains, and classify them into park ranges, basin ranges, plateaus, Sierras of Nevada, Coast range, and Cascade mountains. The three latter ranges have no more reason to be included with the Rocky mountains than the Alleghanies. The uplift beginning in the Pacific ocean, and forming the peninsula of Lower California, continues northward into the lofty Sierras of Nevada, the Cascade mountains in Oregon and Washington, and through Alaska to mount St. Elias, 16,753 ft. high, near the shore of the n. Pacific. In the Sierras of California, mounts Shasta, Tyndall, and many others are upward of 14.000 ft. high; and mounts Jefferson and Hood in Oregon territory, mounts Rainier and Baker in Washington territory, are still This great range is distinctly separated from the Rocky mountain system by the valley of the Colorado river, the great interior basins, and the valleys of the upper Columbia, Fraser, a-nd Yukon rivers. For the geology, natural history. topographical, and climatic details of the Rocky mountain system, see the states and territories trav ersed by them. For Pacific coast ranges see CALIFORNIA., OREGON, WASIIINGTON, and ALASKA.