Uranium oxides in the Chattanooga Shale constitute the largest total tonnage of uranium known in the United States, but the concentration is at best only about a hundredth of that necessary for present economic development. The highest tenors are in the upper five ft of the Chattanooga in the Highland Rim area of Tennessee.

Most large commercial uranium deposits in the United States are roll-type deposits formed in geochemical cells acting on a protore of arkosic, carbonaceous or pyritic, fluvial sandstone. The cells may concentrate uranium more than a thousandfold, but rarely exceed one-percent tenor in the narrow roll front. The best possibilities for commercial uranium in the Appalachians are in fluvial sandstones deposited after the development of abundant land plants. In addition to mineralogic composition and depositional environment, other important factors are paleocurrent trends, unconformities, changes in regional dip through time, and possible removal of uranium cells by Pleistocene glacial scouring. Significant uranium shows are present in Pennsylvania in fluvial-channel sandstones exhibiting evidence of geochemical cells, in both the Devonian Catskill Formation and the Mississippian Mauch Chunk Formation.

Out of 22 fluvial or possibly fluvial Appalachian stratigraphic

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units considered, the most promising ones for uranium exploration are the Devonian Hampshire and Catskill Formations from New York to Virginia, the Mississippian Mauch Chunk-Pennington Group from Pennsylvania to Tennessee, the Pennsylvanian Pottsville Group (especially in Alabama, Virginia, and southern West Virginia), the Pennsylvanian-Permian Dunkard Group in West Virginia, and the Triassic basins of the eastern Appalachians. The following units have moderate promise for uranium exploration: Cambrian Rome Formation from Virginia to Alabama; Ordovician Bays Formation from Virginia to Alabama; Ordovician Juniata Formation from Tennessee to Pennsylvania and equivalent Queenston Formation in New York; Silurian Bloomsburg Formation in Pennsylvania; Mississippian Pocono-Price Formation fr m New York to Virginia; Mississippian Maccrady-Stroubles Formation in Virginia and West Virginia; and Pennsylvanian Allegheny, Conemaugh, and Monongahela Groups from Pennsylvania to Kentucky.

A few uranium shows have been reported from pegmatites and other igneous rocks in the Blue Ridge, but far below commercial concentrations. None of the dikes cutting the Valley and Ridge and Plateau provinces have compositions associated geochemically with uranium, so prospecting them is probably futile.

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