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 Moun tains and the Green Mountain range extend ing 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 ex ceeding 100 miles. The most remarkable feat ure of the general formation of the Appala chians 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 moun tains. This great central valley extends from New York to the southern end of the system, including the Cumberland Valley in Pennsylva nia and the great valley of Virginia and of Tennessee. This region is very fertile through out 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 Biother 6,619 and Mount Hallbacic; 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 picturesqueness' 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 geo logical formations from the metamorphic group of the Pre-Cambrian to the so-called coal measures of the Carboniferous, the latter in cluding sandstones, shales, limestones and coal. The strata of the western slope with their regu lar horizontal arrangement show a great con trast to the disturbed stratification of the east ern slope. There the rock formations are con fused 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 forma tion. After the formation of these strata, prob ably 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. Subse quent erosion by rivers carved the gaps through the ridges so characteristic of the Appalachian topography and gave the mountains their pres ent 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 Ap palachians 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, cop per and lead are found in comparatively small quantities and are of little importance com mercially, but the deposits of marble, limestone, fire-clay, gypsum and salt are abundant and valuable.