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Southern Shale Valleys

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About the Southern Shale Valleys

The Southern Shale Valleys are a region in the southern half of the Ridge and Valley, the southern counterpart to the Northern Shale Valleys in the northern half of this region. This region is one of the two bottomland regions in the Ridge and Valley system, but it makes up a much smaller portion of the total land than the Southern Limestone/Dolomite Valleys and Low Rolling Hills.

This region consists of rolling valleys and some low, rounded hills and knobs. Elevation and relief both tend to be lower here than in any of the surrounding regions. The region is underlain mostly by shale bedrock, with some limestone and siltstone. The bedrock here has been highly weathered, and the material at the surface is mostly formed on highly eroded residuum. In the north, the residuum is more sandy and shaly, whereas in the south there is more clay, clay-loam and sandy-loam. Although soil fertility here is variable, it tends to be much lower than in neighboring areas with predominantely limestone and dolomite bedrock. The bedrock here is low in permeability, and there is a high density of surface streams. The soil here is also more easily erodible.

This region was originally covered mostly in Appalachian oak forest, with a mix of oaks, as well as hickory, pine, poplar, birch, and maple. In the south of this region, there was also some oak-hickory-pine forest on the drier sites. There were also bottomland oak forest on wetter ones, more extensive in the south due to greater occurrence of poorly-drained soils.

There is currently significant agriculture here, although less so than in the neighboring limestone/dolomite valleys. The region mostly produces hay, corn, and tobacco, mostly on small farms. There are small patches of forest, mostly on the steeper sites, as well as some pine plantations, especially in the south. This area suffers from soil erosion and degradation of streams associated with high turbidity.

Within the Ridge and Valley system, this region borders many others. The most common border is with the Southern Limestone/Dolomite Valleys and Low Rolling Hills, another relatively low, flat area with much more fertile soils and slightly higher elevations and relief. There are also borders with the rugged, upland Southern Dissected Ridges and Knobs and Southern Sandstone Ridges.

Although most of this region is entirely surrounded by other parts of the Ridge and Valley region, in one spot it directly borders the Blue Ridge to the southeast, where it has borders with both the Southern Sedimentary Ridges and Southern Metasedimentary Mountains. Similarly, in one small region it borders the Dissected Appalachian Plateau of the Central Appalachians to the northwest.

References

1. Woods, A.J, Omernik, J.M., Brown, D.D. "Level III and IV Ecoregions of Delaware, Maryland, Pennsylvania, Virginia, and West Virginia", U.S. Environmental Protection Agency: National Health and Environmental Effects Research Laboratory, Corvallis, OR (1999) Web.

2. Griffith, G.E.; Omernik, J.M.; and Azevedo, S.H. "Ecoregions of Tennessee (Poster)", U.S. Geological Survey, Reston, VA (1998) Web.

3. Griffith, G.E., Omernik, J.M., Comstock, J.A., Lawrence, S., Martin, G., Goddard, A., Hulcher, V.J., and Foster, T. "Ecoregions of Alabama and Georgia (color poster with map, descriptive text, summary tables, and photographs)", U.S. Geological Survey, Reston, VA (2001) Web.