Four Middle and Upper(?) Ordovician formations are exposed east of Mazourka Canyon in the Independence Quadrangle. The Chazyan Mazourka formation, approximately 500 feet of limestone and shale, conformably succeeds early Ordovician(?) dolomite and belongs to the Pogonip group. The overlying Barrel Spring formation, approximately 150 feet of Mohawkian sandstone, shale, and limestone, is assigned to the Eureka group. Approximately 200 feet of Mohawkian argillaceous limestone, dolomite, and quartzite make up the unnamed remainder of the Eureka group. Approximately 175 feet of Upper Ordovician(?) dolomite resting on the Eureka group is tentatively assigned to the Ely Springs formation. Silurian rocks disconformably succeed the Ely Springs formation.