Appalachian Highlands:
3. Valley and Ridge

The Valley and Ridge province has developed on thick, folded beds of sedimentary rock deposited during the Paleozoic. The long axes of the folded control the shapes and orientations of a series of long, narrow parallel ridges and intervening valleys. The differing degrees of resistance to erosion of the sandstones, shales, and carbonate rocks comprising the lithology determine local relief. In general, the more resistant sandstones cap the ridgetops, protecting softer bedrock below from erosion; limestones and other carbonate rocks form the lowlands and valleys. (see geologic cross-section.)

The Valley and Ridge is subdivided into two subregions, the Valley of Virginia and the Allegheny Mountains.

Physiographic Subregions of the Valley and Ridge

Valley of Virginia

The Valley of Virginia is the regional name for what is actually part of one of the major landform features of eastern North America, the Great Valley, which stretches from New York state southwest to Alabama. Underlain primarily by carbonate rocks, the Valley of Virginia is a region of karst. Solution of the carbonate bedrock has created sinkholes on the surface and many caves and large caverns beneath the surface. The Valley has been an important north-south route of travel since prehistory.

The Valley of Virginia can itself be subdivided into a string of river basins. From northeast to southwest, one encounters the Shenandoah Valley, the James River Valley, The Roanoke Valley, the New River Valley, and the Holston Valley. Elevations vary from basin to basin. The highest divide occurs near Rural Retreat in Wythe County; waters flowing north to the New River or south to the Holston system separate at about 2400 feet above sea level. The valley floor slopes in both directions away from the New/Holston divide. The Holston leaves Virginia at an elevation of about 1400'; the Shenandoah crosses Virginia's northern boundary at about 400 feet above sea level.

Throughout the Valley of Virginia, hills and ridges rise above the general elevation of the valley floor. Massanutten Mt., a 50-mile long folded mountain in the middle of the Shenandoah Valley section, attains an elevation slightly higher than 2000 feet above sea level.

Allegheny Mountains

The Alleghany Mountains are a series of long, parallel folded mountains with narrow valleys in between. Elevations of ridgelines range from about 3000 above sea level in the northern part of the subregion to about 4000' above sea level in the south. The highest peak in the Alleghenies is Beartown Mountain (Tazewell County) at 4700'. Beartown forms part of the rim of a large, bowl-shaped valley, Burkes Garden. This landform is conspicuous in satellite imagery and is the result of erosion of an upward bending fold.

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Created by SLW, January 1997. Last updated August 10, 1999