Park Hall Formation of Calvert and St. Marys Cos., MD, is composed of pink, pale brown, or medium yellow orange silty, fine-grained sand, and fine- to medium-grained sand and clay interbedded with medium- to coarse-grained sand with pebbles, cobbles, and boulders. Coarser material is common at the base. Contains a large amount of sediment derived from the Piedmont, Triassic basin, and Appalachian Mountains. Unit is found mainly in discontinuous meander scars south from Chicamuxen Creek to Rte 301 bridge over the Potomac. Fluvial facies best exposed in the Goose Bay Aggregates pit in western Charles Co.; estuarine facies well exposed in cliffs near Popes Creek. Correlates with Walston Silt of the Delmarva Peninsula, the Windsor Formation of VA, and unnamed shelly marine beds along the Chowan River in NC. Thickness of the estuarine beds 50 to 60 ft. Unconformably overlies Choptank Formation (middle Miocene) in most places, the Pliocene Upland Gravels having been eroded prior to deposition of the Park Hall; unconformably underlies the Pleistocene Chicamuxen Church Formation. Pliocene age based on presence of exotic pollens PTEROCARYA and ULMUS. [Nomenclature is this report reflects the usage of the Maryland Geological Survey.]

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