Appalachian Mountains - geography.

Appalachian Mountains - geography. Appalachian Mountains or Appalachians, great mountain system of eastern North America, nearly parallel with the Atlantic coast, and extending from the province of Québec in Canada to northern Alabama. The system is 2,400 km (1,500 mi) long and varies from 160 to more than 480 km (100 to more than 300 mi) in width. Its altitude varies between 460 and nearly 2,040 m (1,500 and nearly 6,700 ft). The three divisions of the system--northern, central, southern--vary considerably in geologic age, having been raised by a series of crustal plate collisions that began during the Ordovician period and climaxed in the Permian (see Plate Tectonics). The northern division--including the Green Mountains and the White Mountains, the highlands of Maine, the Shickshock Mountains, and the Notre Dame Mountains of Québec--terminates in the hills of Newfoundland and Labrador. The chief ranges of the central section are the Catskill Mountains, Allegheny Mountains or Alleghenies, and Blue Ridge or Blue Ridge Mountains. The Blue Ridge range is the principal uplift of the Appalachians. This range rises from the Piedmont Plateau to heights far greater than the Alleghenies attain. Beginning prominently in South Mountain in Pennsylvania, it stretches southwest in greater and greater heights, through Virginia and western North Carolina, where it divides, the northern branch continuing west to Georgia as the Great Smoky Mountains. This range, a broad mass of mountains on the border between North Carolina and Tennessee, contains peaks higher than those of the White Mountains of New Hampshire. The culminating group of the Blue Ridge is known as the Black Mountains. The highest peak of the Appalachians, Mount Mitchell (2,037 m/6,684 ft), and many peaks above 1,800 m (6,000 ft) in height are situated in this group. The principal range of the southern Appalachians, which extend south into Alabama from the New River valley in Virginia and West Virginia, is the Cumberland Plateau and Cumberland Mountains. Elevations in this range average 610 m (2,000 ft). The Appalachian Mountains are heavily forested and contain deposits of iron ore, anthracite, bituminous coal, zinc, slate, limestone, asbestos, mica, granite, and emery. Along the western slope from southwestern New York through western Pennsylvania, into West Virginia, Kentucky, and Tennessee, lie coalfields. Numerous rivers make their way through the Appalachians. Among the more important are the Connecticut, Hudson, Delaware, Schuylkill, Susquehanna, Potomac, James, and Rappahannock (flowing east or southeast) and the Cumberland, Kanawha, Allegheny, Monongahela, Tennessee, and others (flowing toward the west). Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.