Valley and Ridge Physiography: Drainage (Part 2)
• The New River is one of the oldest streams in the Appalachian Mountains. In Virginia, the New flows northwest across the trend of the Valley and Ridge province.
The New River is not new, but is one of the oldest streams in North America. It flows across three major Appalachian provinces (the Blue Ridge, the Valley and Ridge, and the Appalachian Plateaus). Geologists believe the New River is very old because it is able to flow northwestward across the northeast-southwest regional trend of the Appalachians. The New might trace its ancestry to the late Paleozoic when it and other streams flowed down the northwestern side of the young Appalachian Mountains. Shown on the map is the area of the New River north of Radford, VA. In the northern part of the map, the river clearly cuts across the ridge lines. (Map data: Google)
Water gap at Narrows. The New River has cut this spectacular gap through hard Silurian sandstones at Narrows. The fact that the river flows through the ridge instead of parallel to it indicates that the river is very old. The river may have formed before the present topography. (Image courtesy of the Virginia Division of Geology and Mineral Resources)
The eastern continental divide (shown in red) runs through southwestern Virginia. West of this divide, water flows north and west and eventually to the Gulf of Mexico. East of the divide, water flows east and goes to the Atlantic Ocean. (Image courtesy of the Virginia Division of Geology and Mineral Resources)
• Waterfalls are common features in the Valley and Ridge and Plateaus because many streams flow across ledges of resistant rocks.
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Alleghany County is the location of an unusual waterfall called Falling Spring Creek Falls. This creek is fed by a thermal spring and flows over an ancient travertine deposit, which creates the falls.