COLORADO, kol-o-rii'do, the ((Centennial State (admission to the Union planned for 4 July 1876, consummated 1 August), is bounded north by -Wyoming and western Nebraska, south by New Mexico and western Oklahoma, east by Kansas and Nebraska, west by Utah. Capital, Denver. Area, 103,925 square miles (280 of it water). Pop. 799,024.
Topography.— Eastern Colorado, one-third the total area, is the westernmost portion of the great treeless plains that continue the Kansas prairies. Near the abrupt rocky faces of the mountains, they rise in low sharp-ridged foot hills, called composed of an exten sive series of fresh water and marine forma tions (remnants of the junction of sedimentary with primary rock). The remainder of the State belongs entirely to the Rocky Mountain system. The Front Range connects the plains with the main range of the system. The western portions fall in minor slopes toward the Pacific. Colorado contains the greatest mass of high land in the United States, if not on the continent.
The main mass of the Rockies crosses Colorado in two principal lines of elevation. The eastern, or more recent line, is composed of the Medicine Bow Range, which extends into Wyoming; the Front Range, the one first en countered by the early immigrants and still crossed by the main line of transmontane travel, the Sangre de Cristo and the Culebra. The western, or main line, is composed of the Park Range from the north and the Sawatch Range, which is a continuation of the Sierra Madre of Mexico. West of these main lines lies a compli cated series of broken ranges and plateaux, parallel, lateral and oblique, but with a general trend northwest and southeast. Of these the principal ones are the Roan or Book, north of the Grand River in the extreme west; the Un compahgre parallel to the Gunnison River on the south; the San Miguel further south; the San Juan to the east; and the Elk near the centre obliquely to the Sawatch (incorrectly spelled Sagauche). The Elk is a very notable range about 30 miles long, geologically inter esting from the extraordinary displacement of strata, with a number of lofty and rugged sum mits; Castle Peak, 14,259 feet; Maroon, 14,003 feet ; Snow Mass, etc.
The best-known peaks in the State, Long's (14,271) and Pikes (14,108), noted landmarks of the immigrant trail, are in Front Range, which also contains Audubon, Arapahoe, James, Rosalie, Grays (14,341), Torreys (14,336) and Evans (14,330). The loftiest range, as a whole, is the Sawatch, a granite mass over 13,000 feet high for many miles together and from 15 to 20 miles wide. Its peaks are Harvard (14,375), Princeton (14,196), Yale (14,187), and others. After a depression of 18 miles, the range rises in the Mountain of the Holy Cross, where a deep ravine and a transverse fissure outline a gigantic cross in the snow. The highest point in the State is Mount Massive (14,424).
The great passes are far higher than any mountain summits east of the Rockies. There are several over 10,000 feet above sea-level : Al pine (13,550), Cottonwood (13,500), Argentine (13,286), Marshall (10841), Tennessee (10,418) and Fremont (11,313).
Lying between the two parallel elevations are four great parks which are separated from each other by cross ranges. By far the largest is San Luis Park, which extends into New Mexico and has an altitude of about 7,000 feet and lies between the Sangre de Cristo and Cu lebra ranges on the east and the Sawatch on the west and is more nearly level than the plains. It is nearly the size of Massachusetts. It is drained by the Rio Grande through the southern centre, while the mountain streams of the north flow into the San Luis Lake, the largest lake in Colorado. North of San Luis Park is South Park, between Front and Mosquito ranges, 8,000 to 12,000 feet high, and about the size of Rhode Island. Further north is Middle Park, still more elevated and somewhat larger. Lying be tween Medicine Bow and Park ranges is North Park, the second in size. There are many smaller parks, the most famous of which are Monument Park and the Garden of the Gods near Colorado Springs; in the latter arise towers and pinnacles consisting of the vertical strata of the white Dakota sandstone and of the red triassic sandstone below. Some of these huge masses rise vertically for 200 or 300 feet, and serve as examples of erosion of steeply up turned strata of varying consistency. Lower white ridges of Jurassic gypsum or Cretaceous limestone afford strong contrast in color when compared with the red sandstone?' River Systems.--The main Rocky Moun tains must obviously be the greatest of Ameri can watersheds and chief source of river sys tems, except Minnesota; they contain the con tinental divide between the waters flowing to the Atlantic and those flowing to the Pacific. One part of it is the southern boundary of North Park, the streams of which flow north to the Platte-Missouri-Atlantic system, those south of it feed the Grand-Colorado-Pacific; another is between Creede and Ouray, separating the headwaters of the Rio Grande from those of the Gunnison and Uncompahgre of the Colo rado system. The eastern plains are divided chiefly between the two great systems of the Arkansas and the South Platte; the former occupies more than one-half their area in the State, the southern portion ; the South Platte, the larger portion of the northern half ; be tween them on the east is a section draining into the Republican River, an affluent of the Kansas. The South Platte rises in South Park; the Arkansas in the mountains west of it, Lead vine lying on one of its head creeks. Except for these and the Rio Grande in San Luis Park, the mountain section is almost entirely drained by the Colorado River system; the Yampa (or Bear) and the White, in the northwest, flowing to the Green; the Grand through the centre, with its chief affluent the Gunnison from the south; and the Dolores in the southwest.