Following the informal usage of Lee (1979, 1980), the Tuscarora Creek Member of the Manassas Sandstone is here named for exposures along the southeast bank of Tuscarora Creek, Frederick Co., MD. It consists of limestone and dolomite clast conglomerate in a matrix of limestone granules, sand, and silt, and is the basal unit of the Manassas along the northeastern border of the Culpeper basin in the Frederick Valley. It unconformably overlies Frederick Limestone and is laterally and vertically gradational with the Poolesville Member of the Manassas. Thickness varies from a wedge edge to 70 m (230 ft). Age is Late Triassic (probably late Carnian) based on spores and plants in the overlying Poolesville Member.

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