The Encyclopedia Americana (1920)/Appalachian Mountains

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APPALACHIAN MOUNTAINS, the great mountain system of the eastern United States extending from northern Alabama into the State of New York and according to the best recent opinion embracing also the New England system. Thus defined it includes a number of ranges and mountain groups of which the most important are the Alleghanies, the Blue Ridge, the Cumberland, the Black Mountains, the Catskills (formerly regarded as the northern termination), the White Mountains and the Green Mountain range extending northward to the Laurentian formations. But in comparison with this great length north and south, its measurements east and west are very moderate, the width at no point much exceeding 100 miles. The most remarkable feature of the general formation of the Appalachians is the regular arrangement of its ridges and valleys, these being, in general, parallel to the Atlantic coast line. This arrangement is particularly noticeable in the central part of the system, through Pennsylvania and Virginia. In general the ridges lie along two parallel lines from 50 to 100 miles apart, thus enclosing a longitudinal valley whose sides rise rather abruptly to culminating points of the mountains. This great central valley extends from New York to the southern end of the system, including the Cumberland Valley in Pennsylvania and the great valley of Virginia and of Tennessee. This region is very fertile throughout its whole length, and is especially well cultivated in Lancaster, Berks and Lehigh counties, Pa. The Appalachians show no remarkable elevations and the height of the summits appears less than it really is, because the mountains rise from a plateau varying from 500 feet in Pennsylvania to 1,500 and 2,000 feet in Virginia and Tennessee. The lowest peaks are found in Pennsylvania, none rising much above 2,000 feet. The culminating point of the whole system is Mount Mitchell, in the Black Mountains (6,711 feet); others of the high peaks, also found in the Black Mountain range, are Balsam Cone 6,671 feet, Black Brother 6,619 and Mount Hallback; the Smoky Mountains, too, include some high peaks, for example, Clingmann Dome 6,619, Guyot 6,636, Mount Alexander 6,447, Mount Seconto 6,612 and Mount Curtis 6,568. The culminating point of the northern part of the system is Mount Washington, New Hampshire (6,233 feet). The peaks are generally of rounded outline and lack the bold picturesquencss that characterizes the Rocky Mountains and other geologically “young” ranges in the western United States. Their low altitude and smooth contour are the result of the long-continued erosion which has removed great thicknesses of strata since the first uplift.

Geology— The Appalachians show all geological formations from the metamorphic group of the Pre-Cambrian to the so-called coal-measures of the Carboniferous, the latter including sandstones, shales, limestones and coal. The strata of the western slope with their regular horizontal arrangement show a great contrast to the disturbed stratification of the eastern slope. There the rock formations are confused and pressed into folds and wrinkles with an inclination generally southeast. The strata of the system are all of marine or terrestrial origin, the latest being those of the coal formation. After the formation of these strata, probably during Permian time, the mountains were elevated to their present position by a force that proceeded from the southeast, working probably by many successive impulses. Subsequent erosion by rivers carved the gaps through the ridges so characteristic of the Appalachian topography and gave the mountains their present conformation. The chief minerals of the Appalachians are iron and coal. Iron ores, magnetite, hematite, and limonite, are very abundant; the magnetic iron is found especially in what is called the Champlain Iron District The hematite and limonite ores are found all along the great Appalachian Valley and are of great commercial importance; while the earthy carbonite of iron found in many parts has been largely manufactured. Coal is perhaps the most important product; the coal deposits of the Appalachians include the whole anthracite field of Pennsylvania and New York with an area of 400 to 500 square miles, and the bituminous fields of Pennsylvania and other States, with an area of 56,000 square miles. Gold, silver, copper and lead are found in comparatively small quantities and are of little importance commercially, but the deposits of marble, limestone, fire-clay, gypsum and salt are abundant and valuable.

Drainage.— The Appalachians form the watershed between the Atlantic Ocean and the Mississippi River systems; this does not lie in one continuous line, but shifts its position from one line of ridges to another, so that many of the rivers cut their way through the mountains from west to east, or east to west; the Delaware and Susquehanna, for example, with their branches. These two rivers, with the Potomac and James, drain much of the eastern slope; the Ohio, with its tributaries, is the chief means of drainage on the western slope.

Flora and Fauna.— The mountain slopes are heavily wooded throughout the whole system. The white pine is found in all portions; the sugar maple, the white birch, ash and beech grow on the northern mountains; the oak, cherry, white poplar, white and yellow pine farther south. On the poorer lands the evergreens flourish, such as spruce, hemlock and balsam-fir, which, on account of their dark foliage covering the summits of the Black Mountains, have given this range its name. There are large quantities of flowering shrubs, particularly the rhododendrons, azaleas and laurel often growing in almost impenetrable thickets, and many varieties of smaller plants and flowers. Panthers and wolves have practically disappeared from the mountains, but bears, deer and wild-cats are quite common. Small game birds are plentiful and wild turkeys also on the southern ranges. Rattlesnakes and copperheads are found in all parts of the Appalachians, but not in great numbers.

Bibliography.— Barrell, J., ‘The Upper Devonian Delta of the Appalachian Geosyncline’ (In American Journal of Science, series 4, Vols. XXXVI and XXXVII, New Haven 1913-14); Guyot, ‘The Appalachian Mountain System’ (American Journal of Science, series 2, Vol. XXXI); Hayes, ‘The Mechanics of Appalachian Mountain Structure’ and ‘Physiography of the Chattanooga District’ (Annual Report of United States Geological Survey, XIII and XIX); Kephart, H., ‘Our Southern Neighbors’ (New York 1913); Morley, M. W., ‘The Carolina Mountains’ (Boston 1913); Rogers, H. D. and W. B., ‘Physical Structure of the Appalachian Chain’ (American Journal of Science, series 1, Vol. XLIV); Stockbridge, H. E., ‘A Bibliography of the Southern Appalachian and White Mountain Regions’ (Washington 1911); Willis, B., ‘The Northern Appalachians’ (New York 1895).

Marrion Wilcox.