Clingmans Dome, like most of the Smokies, consists of a type of lightly metamorphosed sedimentary rock (especially sandstone) that is part of a formation known as the Ocoee Supergroup. These rocks were created from ancient ocean sediments nearly one billion years ago. Although a dense forest understory covers most of the mountain, this rock type is noticeable in rock outcroppings and in a large boulder pile at the Forney Ridge Parking Lot at the end of Clingmans Dome Road.