Is Lower Cretaceous formation mapped near southeast end of Chinati Mountains in Chinati Peak quadrangle, Presidio Co, TX (southern part of Permian basin). Overlies Presidio Formation (Lower Cretaceous). Overlain by Del Carmen Limestone (Lower Cretaceous). Map unit described as limestone, sandstone, shale, and marl; limestone, nodular to regularly bedded, beds thin to medium, alternating hard and marly units form a series of cuestas; sandstone predominates in basal 50 ft, near middle of formation, fine to medium grained, thin to medium bedded, cross-bedded, ripple marked, weathers dark reddish brown; marine fossils include EXOGYRA TEXANA in upper 165 ft, ORBITOLINA in lower 700 ft, and various other marine megafossils, petrified wood in some sandstone beds; formation is 900 ft thick, crops out in Chinati Peak quadrangle and Presidio area.

Source: GNU records (USGS DDS-6; Denver GNULEX).