either Threatened or Endangered by either the State or Federal government. Ammocrypta vivax, Scaly Sand Darter Cyprinella monacha, Spotfin Chub – Federal Threatened status Etheostoma aquali, Coppercheek Darter – State level Threatened status Etheostoma boschungi, Slackwater Darter – Federal Threatened status Etheostoma cinereum, Ashy Darter – State level Threatened status Etheostoma denoncourti, Golden Darter Etheostoma pseudovulatum, Egg-Mimic Darter – State level Endangered status Percina burtoni, Blotchside Darter Percina macrocephala, Longhead Darter – State level Threatened status Crustacean The Alabama crayfish, Orconectes alabamensis is a rare crayfish species found near the Buffalo. Mussels Three species of mussels are among the rare species listed by TDEC. Both the Cracking Pearly Mussel and the Pale Lilliput are listed by both State and Federal authorities as Endangered. Hemistena lata, Cracking Pearly Mussel Quadrilla cylindrical cylindrical, Rabbitsfoot Toxolasma cylindrellus, Pale Lilliput Snails Four species of rare snails are found near the Buffalo; none of them are included by TDEC on species concerns lists. Leptoxis praerosa, Onyx Rocksnail Lithasia duttoniana, Helmet Rocksnail Lithasia geniculata fuliginosa, Geniculate Rocksnail Lithasia geniculata fulginosa, Geniculate Riversnail Geology Except for a very small section on the southern end, the watershed is part of the Western Highland Rim, one of 25 Level IV subecoregions in the state. The dissected, rolling terrain is characterized by long ridges with steep sides and hollows deeply eroded into those ridges. The river flows in a wide flood plain of "bottom land". The elevation varies from . The predominant geology of the area is that of Paleozoic limestones. The Mississippian limestone base along with chert and shale is overlaid by fairly thin soils of moderate fertility. These tend to be acidic. Much of the differential erosion leading to the terrain features results from differences in deposition and mineralization of the various types of limestone in the area and the presence of large portions of chert. Some chert bears small quantities of the iron-containing mineral hematite or other oxides of iron. During the mid-to-late 19th century there was considerable iron-ore related mining and smelting of Limonite ore. The sizable tributary streams flow out of narrow hollows into the Buffalo; only the largest ones have true stream valleys of their own. Streams are typically clear with a moderate gradient. Economy Canoeing float trips significantly contribute to the area's economy. The area's remoteness depresses the local economy compared to that of the state as a whole. The Middle Tennessee Council