Valley And Ridge Province

  • Type: Physiographic Province

Nevin M Fenneman, American geologist and geographer, described The Valley and Ridge Province of the Appalachian Highlands in 1938 and were defined on a US Geological Survey Map by Fenneman and Johnson in 1946. The province begins in the St Lawrence Lowland and extends 1200 miles to Alabama. The Valley and Ridge Province is commonly divided into three sections: the northern segment, known as the Hudson-Champlain section, a middle section extending from the Delaware River to the New River in southern Virginia and a southern section from southern Virginia to the end of the highlands in Alabama. The Valley and Ridge Province is fairly narrow, ranges from about 20 miles in New York near the Hudson River to about 80 miles in width in central Pennsylvania between Williamsport and Harrisburg. - AsNotedIn

The erosional characteristics of the sedimentary rock formations exposed along great anticlines and synclines of the Appalachian Mountains are responsible for the characteristic Valley and Ridge topography. Durable layers of sandstone and conglomerate form ridges, whereas less resistant limestone and shale underlie the valleys in the region. Along the eastern margin of the Valley and Ridge is the Great Valley, a broad valley underlain by Cambrian and Ordovician shale and carbonate rocks that weather and erode faster that more durable sandstone and conglomerate that crop out in ridges and plateaus to the west (see Figure 52). It extends southward from the Adirondack Mountains region, encompassing the upper Hudson River Valley between the Taconic Mountains (to the east) and the Catskills (to the west). It gradually bends westward into northern New Jersey, forming a broad, low valley broken by long, low ridges. It is bordered by the Highlands of the Reading Prong on the south and east, and the high ridge of Kittatinny Mountain to the west. In New Jersey and eastern Pennsylvania, Kittatinny Mountain represents the eastern-most hogback ridge of Middle Paleozoic rocks of the Valley and Ridge. North of New Jersey the characteristic folds of the Valley and Ridge fade into the nearly flat-lying strata of the Catskills region and the Allegheny Plateau region of western New York and Pennsylvania. In the New York Bight region, the Allegheny Plateau and the Catskill Mountains of Pennsylvanian and New York are the northern extension of the greater Appalachian Plateau. - USGS


Geography »


Alternating beds of hard and soft Paleozoic sedimentary rocks, folded like the wrinkles in a kicked floor rug, are the hallmark of the Appalachian Valley and Ridge Province. Extending some 900 miles (1500 km) from New York to Alabama, and flanked by flat-lying sedimentary strata to the west and Precambrian metamorphic rocks to the east, this famous belt of parallel structures reflects the several great continental collisions that formed the Appalachian chain and the Pangaea supercontinent some 300 to 400 million years ago. - USGS

Physiographic Region Physiographic Province

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