Named from good exposures on and in the neighborhood of O. K. ranch, sec 31, T25N, R9E, Osage Co, OK, Chautauqua platform. Extends to the southern line of T24N; does not crop out north of Clear Creek in T25N. No type locality designated. Is the lowest limestone in the Pawhuska formation (revised); lies about 10 ft above the highest bed of the Elgin sandstone; lies 50-100 ft below the Deer Creek member of the Pawhuska. Is a thin limestone ranging in color from gray to buff with the buff color predominating. In most places, is of flinty hardness and contains abundant small FUSULINA; however, either or both of these features may be locally absent. Stratigraphic sections. Of upper [Late] Pennsylvanian age.

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