- Ridge-and-Valley Appalachians
The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a physiographic province of the larger Appalachian division and are also a belt within the
Appalachian Mountains extending from northernNew Jersey westward intoPennsylvania and southward intoMaryland ,West Virginia ,Virginia ,Tennessee , andAlabama . They form a broad arc between theBlue Ridge Mountains and theAppalachian Plateau physiographic province (the Allegheny and Cumberland Plateaus).These mountains are characterized by long, even
ridge s, with long, continuousvalley s in between. From a great enough altitude, they look almost likecorduroy , except that the widths of the valleys are somewhat variable and ridges sometimes meet in a vee.Geography
The two great mountain ranges constituting the middle portion of the Ridge and Valley Province are the Alleghenies and the Cumberlands.Fact|date=April 2008
The eastern edge of the Ridge and Valley region is marked by the
Great Appalachian Valley , which lies just west of the Blue Ridge. The western side of the Ridge and Valley region is marked by steep escarpments such as theAllegheny Front , theCumberland Mountains , andWalden Ridge .Geology
These curious formations are the remnants of an ancient fold-and-thrust belt, west of the mountain core that formed in the
Alleghenian orogeny (Stanley, 421-2). Here, strata have been folded westward, and forced over massivethrust faults ; there is little metamorphism, and no igneous intrusion.(Stanley, 421-2) The ridges represent the edges of the erosion-resistant strata, and the valleys portray the absence of the more erodible strata. Smaller streams have developed their valleys following the lines of the more easily eroded strata. But a few major rivers, such as theDelaware River , theSusquehanna River , and thePotomac River are evidently older than the present mountains, having cutwater gap s that are perpendicular to hard strata ridges. The evidence point to a wearing down of the entire region (the original mountains) to a low level with little relief, so that major rivers were flowing in unconsolidated sediments that were unaffected by the underlying rock structure. Then the region was uplifted slowly enough that the rivers were able to maintain their course, cutting through the ridges as they developed.Valleys may be synclinal valleys or anticlinal valleys.
These mountains are at their highest development in central Pennsylvania, a phenomenon termed the "Pennsylvania climax".
ignificant ridges
Name State Allegheny Mountain Virginia and West Virginia Bald Eagle Mountain Pennsylvania Bays Mountain Tennessee Blue Mountain Pennsylvania Cacapon Mountain West Virginia Clinch Mountain Tennessee and Virginia Great North Mountain Virginia and West Virginia Jacks Mountain Pennsylvania Kittatinny Mountains New Jersey Knobly Mountain West Virginia Mill Creek Mountain West Virginia New Creek Mountain West Virginia Nittany Mountain Pennsylvania North Mountain Virginia and West Virginia North Fork Mountain West Virginia Patterson Creek Mountain West Virginia Powell Mountain Tennessee and Virginia Red Mountain Alabama Shawangunk Ridge New York Sideling Hill West Virginia, Maryland, and Pennsylvania Sleepy Creek Mountain West Virginia South Branch Mountain West Virginia Spruce Knob West Virginia Tuscarora Mountain Pennsylvania Tussey Mountain Pennsylvania Wills Mountain Pennsylvania and Maryland Photo gallery
ee also
*
Geology of the Appalachians
*Allegheny Front
*Eastern Continental Divide
*Tennessee Valley Divide References
*Stanley, Steven M. "Earth System History". New York: W.H. Freeman and Company, 1999. ISBN 0-7167-2882-6
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