Is Lower Cretaceous formation mapped near southeast end of Chinati Mountains in Chinati Peak quadrangle, Presidio Co, TX (southern part of Permian basin). Overlies Permian rocks. Overlain by Shafter Formation (Lower Cretaceous). Map unit described as conglomerate, limestone, sandstone, and siltstone; a basal well indurated pebble- to boulder-conglomerate, 30 to 80 ft thick, grades upward to slightly indurated pebbly sandstone and siltstone, followed by a succession of alternating impure carbonate rocks, calcareous sandstone, and siltstone; carbonate rocks weather yellowish gray, other rocks are medium to dark gray and weather yellowish and reddish brown; ORBITOLINA TEXANA common in upper half; thickness about 400 ft; crops out in Chinati Peak quadrangle and Presidio area.

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