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Knobs-Lower Scioto Dissected Plateau

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About the Knobs-Lower Scioto Dissected Plateau

The Knobs-Lower Scioto Dissected Plateau is a region of the Western Allegheny Plateau of the Appalachians, extending from southern Ohio into eastern Kentucky; the region is quite narrow at its southern end.

This region is strongly dissected plateau with geologic features spanning a wide range of ages. It featuring ridges, rounded hills, both wide and narrow valleys, and both steeper and gentler slopes, with some cliffs. The northern limit of glaciation lies in the north of this region, but that region was not glaciated recently, and most of the region is unglaciated. The underlying bedrock is shale and sandstone, and valley bottoms have abundant colluvium, unconsolidated sediments accumulating at the base of the steep slopes. In the north, there is some highly leached glacial till from the Illinois period.

Prior to glaciation, the Teays river flowed through this region, and its wide valleys provide a corridor of flat bottomlands in addition to the floodplains of present rivers. The bottomlands are underlain by easily-erodible shales, and can be flat and swampy, but this region also has some of the most rugged terrain in any part of the the Western Allegheny Plateau. Elevations range from 490-1,350 feet with local relief of 300-800 feet.

The climate here is towards the colder end of a humid subtropical climate. The frost-free period ranges from 150-185 days. Precipitation is roughly equally distributed year-round.

This area was naturally almost entirely forested. In the west there was mostly mixed mesophytic forest, and in the east, mixed oak forest. Especially in Kentucky, oak-pine forests can also be found on upland knobs. Bottomland forests are found in river valleys, including both that of the present-day Scioto river, and the former Teays river, an ancient river that once drained this area in the pre-glacial period. In the north there are also oak-sugar maple forests on glacial outwash terraces.

This area is currently mostly forested, but the forests represent regrowth after harvesting of the original forests. Current forest cover is mostly mixed oak forest with some red maple in the understory, and hemlock hardwood forests in ravines. There is also some general farming, livestock production, and tobacco farming. Agriculture is concentrated mostly in the river valleys, although there is some in the flatter uplands as well. The lack of fossil fuel deposits in this area has spared this region from the environmental problems associated with coal mining, which affect many regions farther east.

This area is bordered to the east by the Ohio/Kentucky Carboniferous Plateau in the north, in the middle, by the Carter Hills, and in the south by the Northern Forested Plateau Escarpment. To the north, at the limit of more recent glaciation, the region is bordered by the Loamy High Lime Till Plains. In the north there is a small border to the west with the Pre-Wisconsinan Drift Plains, but most of the region is bordered to the west or northwest by the Outer Bluegrass region. At the far southern end, there is also a small border to the southwest with the Knobs-Norman Upland.


1. Woods, A.J, Omernik, J.M., Brockman, C.S., Gerber, T.D., Hosteter, W.D., Azevedo, S.H. "Ecoregions of Indiana and Ohio (Poster)", US Geological Survey (1998) Web.

2. Woods, A.J., Omernik, J.M., Martin, W.H., Pond, G.J., Andrews, W.M., Call, S.M, Comstock, J.A., and Taylor, D.D. "Ecoregions of Kentucky (Poster)", U.S. Geological Survey, Reston, VA (2002) Web.