Text Box:  
Ridge and Valley Intro | Rocks, Geological Formations | Karst Features | Resources

The Ridge and Valley (also Valley and Ridge) province extends from New York to Alabama, as do the Piedmont Plateau and Appalachian Plateaus provinces.  The northern tip of the province is the northern end of the Hudson Valley, which terminates at approximately east-central New York (although some maps show the province extending northward to the Canadian border).  The southernmost part of the province is approximately 1,200 miles to the southwest near the center of Alabama, midway between the cities of Tuscaloosa and Montgomery.  The province is 14 to 80 miles in width, being narrowest at the New York-New Jersey boundary and widest in east-central Pennsylvania. 
The province is sometimes referred to as the Folded Appalachians or Appalachian Foldbelt because of the synclinal-anticlinal nature of most of the underlying geology.  However, folding also occurs in surrounding provinces, and in some sections of the Ridge and Valley province there has been extensive faulting, which locally may be more significant than folding, and thus the name Ridge and Valley is more appropriate.  The province consists mostly of valleys, many parallel to one another, separated by ridges, also parallel to each other and to the valleys.  Many of these features trend the same direction as the province–northeast to southwest.  Extending along the entire eastern edge is an essentially continuous valley.  Variously called the Great Valley, Great Appalachian Valley, and the Appalachian Valley, this lowland does not have a single major ridge extending across it in its entire length; there is one isolated ridge in the Virginia portion of the valley, called Massanutten Mountain, that trends the same direction as the valley for 45 miles.  The Great Valley varies in width from about 2 to 50 miles, in most places being 5-10 miles wide.  Some sections of the valley have locally-applied names, including Hudson Valley near the eastern border of New York, Walkill Valley in southeastern New York, Lebanon Valley in southeastern Pennsylvania, Cumberland Valley in Pennsylvania and Maryland, Hagerstown Valley within the Cumberland Valley in Maryland, Shenandoah Valley in Virginia, Great Valley of East Tennessee (or Valley of East Tennessee), and Coosa Valley in northwestern Georgia and east-central Alabama. 
The ridges of the province are generally spaced 6-10 miles apart, but have a great range in lengths.  Clinch Mountain, one of the prominent ridges, extends northward from near Knoxville, Tennessee for 145 miles into Virginia.  Three ridges composed of sandstone and conglomerate that join each other end-to-end extend essentially continuously for 200 miles, although water gaps, including the Delaware Water Gap, cut through the ridges at a few places.  These three ridges are the Shawangunk Mountains (locally referred to as the Gunks, especially by the many rock climbers that scale the excellent cliffs), which are about 50 miles northwest of New York City and are 45 miles long, and continue into northwestern New Jersey and east-central Pennsylvania as Kittatinny Mountain, and into Pennsylvania as Blue Mountain.  Another of the most prominent ridges, and distinctly separate from the others, is Lookout Mountain.  This ridge is sometimes included in the Ridge and Valley province but is also said to be in the Appalachian Plateaus; some consider the Tennessee portion to be in the Ridge and Valley province and the rest of the ridge, in northwestern Georgia and northeastern Alabama, to be in the Appalachian Plateaus.  Within the Tennessee portion of this ridge is subterranean Ruby Falls (different than Anna Ruby Falls north of Helen, Georgia), which is several hundred feet beneath the surface in a cave system, and is a sheer waterfall 145 feet tall; it is the tallest underground waterfall on Earth.  (Lookout Mountain is discussed further in the chapter dealing with the Appalachian Plateaus province.)
The number of ridges and valleys across the width of the province varies considerably.  In the northernmost part there are no ridges:  the Hudson Valley covers the entire width of the province there.  Between the Hudson River and the Delaware River there is just one ridge, which is along the western border–the continuous ridge comprising the Shawangunk and Kittatinny mountains.  Ridges are rare across the 70-mile width of the province at Knoxville, Tennessee, with the Great Valley of East Tennessee occupying essentially the entire width of the province.  In contrast, some sections have as many as 10 ridges, often all parallel, between the eastern and western province borders.  The portion of the province between the Susquehanna and James rivers (i.e., from central Pennsylvania to west-central Virginia) has the most regular succession of nearly parallel ridges and valleys; many of the ridges here are the same elevation. 
 Ridge and Valley Intro | Rocks, Geological Formations | Karst Features | Resources