Devil's Graveyard Formation (New) Eocene and Oligocene Age Trans-Pecos Texas

The Devil's Graveyard Formation (new, Eocene and Oligocene) is described as that part of the Buck Hill Group above the Cretaceous and beneath the Mitchell Mesa Rhyolite or the Yellow conglomerate of Moon (1953). It replaces the terminology used by Moon (1953) for the lower part of the Buck Hill Group, Buck Hill Group undifferentiated, as well as Pruett-Duff (Erickson, 1953, and Stevens, 1978) and Pruett and Duff undivided (Barnes, 1979, and Henry and Deux, 1981). The names Pruett and Duff apply to the mountain area in the southern part of the Davis Mountains where their type sections are located. The lithology of the Devil's Graveyard Formation is predominantly clastic and sufficiently different from that of both the Pruett and Duff formations to warrant its new name. The Buck Hill Group in the Agua Fria-Green Valley area consists of the Devil's Graveyard Formation, the Mitchell Mesa Rhyolite, the Tascotal Mesa Formation, and the Rawls Basalt. The Devil's Graveyard Formation is divided into lower and middle unnamed members an upper Bandera Mesa Member, each separated by concentrations of channel conglomerates. Locally useful marker beds that are associated with vertebrate fossil localities are described. The areas of exposure are in west-central Brewster and east-central Presidio counties, Texas.