The Ozan is "mapped in Ouachita tectonic belt province, eastern Dallas, east-central Ellis, and northeast Hill Co., TX and east Texas basin, Rockwall, Kaufman, and Navarro Cos. Clay, calcareous, silt and sand content increases up, montmorillonitic, blocky, conchoidal fracture, med. gray; some glauconite, phosphate pellets, hematite and pyrite nodules; v. thin limestone lenses locally in lower part; grades up to Wolfe City Fm., thickness 500 +- ft."