Named as the top member on the Iowa shelf in northern IA of the Little Cedar Formation (new) of Cedar Valley Group (rank raised) for Hinkle Creek. Type locality is at Garrison Quarry, E1/2 SW SE sec 28 and NE NW NE sec 33, T85N, R11W, Benton Co, IA. Conformably overlies Eagle Center (new) or Bassett Member [not as shown on nomenclature chart] of Little Cedar. Disconformably overlain by Coralville Formation. Conformably overlies Rapid Member (reassigned) of Little Cedar along its southern extent. Characterized by dense nonfossiliferous sublithographic limestone and dolomitic limestone at type where it is 2.5 m thick. Limestone may be laminated, pelleted, intraclastic, and have birdseye fabrics and may be fractured to brecciated. Some argillaceous beds. Desiccation cracks. Some burrowed strata, ostracods and brachiopods. Includes gypsum and anhydrite in central IA. Toward eastern margin, includes laminated limestone interbedded with thin fossiliferous limestone that carries brachiopods, echinoderms, favostids, domal stromatoporoids. Averages 2.5 m thick. Ranges between 0.4 and 4.1 m. Deposited in evaporitic tidal flats and associated restricted lagoonal environment. Nomenclature charts, cross section, graphic section. Of Givetian, late Middle Devonian age.

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