Gray Fossil Site Stratigraphy

The stratigraphy is complex, and unfortunately, some of it was permanently destroyed. Most of the vertebrate material seems to lie in the dark layered organic-rich clay, and the dark clays with sand and gravel. These clays contain lenses and layers of angular chert gravel, with clasts of local dolomite. Gravels were found to occur beneath them along Route 75, and they may have graded laterally into the gravels. Within the lower part of the dark clays are a number of large dolomite blocks. The dark clay and gravels overlie a thick horizon of gray layered clay. Layers above the dark clays are now missing.

The Tennessee Department of Transportation drilled a number of holes along the two planned rights of way, and twelve additional on the Barry Property, the remaining part of the hill south of the excavation. They indicated an area perhaps 700 feet long underlain by layered clays to substantial depth. One drill hole indicated the presence of additional dark carbonaceous clay at depth, beneath the thick gray layered horizon.