the rock from which russell cave was carved was formed over 300 million years ago at the bottom of an inland sea covering the region. due to continental drift, the area that is now northeast alabama was located very close to the equator at the time this limestone was forming. this area is now located in a temperate climate, but 300 million years ago it was a shallow, tropical sea. carbonaceous deposits of skeletons and shells were slowly transformed into limestone. rainwater, mildly acidic from atmospheric carbon dioxide, slowly dissolved a portion of the limestone rock, resulting in the formation of the cave. about 9,000 to 12,000 years ago, the collapse of a cavern roof beneath a hillside near doran's cove created a sinkhole and exposed russell cave.