The Chowan River Formation of the Chesapeake Group, here named, was previously mapped as the Yorktown Formation and Croatan Formation. The upper Pliocene part of the Croatan, here abandoned, is assigned to the Chowan River. The Chowan River Formation represents an unconformity-bounded late Pliocene marine transgression and regression in the Coastal Plain of northeastern NC and southeastern VA, and consists of shelly, silty sand and laminated and trough cross-bedded sand and silt. It is divided into the lower Edenhouse Member consisting of marine shelly, silty sand, and the upper Colerain Beach Member consisting of sandy, silty clay. Unconformably overlies the Morgarts Beach Member of the Yorktown Formation; unconformably underlies the James City Formation. Age is late Pliocene.

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

The Chowan River Formation crops out in northeastern NC within the northern part of the Albemarle embayment. Marginal marine deposits of the Chowan River occur near Suffolk, Norfolk, Hampton, and Cape Henry, VA. Correlative deposits in SC are referred to the Bear Bluff Formation. Chowan River is a regressive sequence of shelf sands containing open-marine molluscan assemblages, overlain by inner-bay, back-barrier, and marginal marine clays, silts, and silty sands. Best exposures occur on Wiccacon Creek, the Chowan River, the Roanoke River and on the Tar River. Unconformably underlies the James City Formation locally in NC. Unconformably overlies the Yorktown Formation. Age is late Pliocene.

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

Though previously correlated with the lower Waccamaw by M. Campbell (1992), author believes the Chowan River to be older and correlates the unit (in part) with the Moore House of Ward and others (1991) and Krantz (1991). (The Moore House in this report is restricted to beds of its stratotype at 3.5 Ma.) The Chowan River of this report is equivalent to beds K-13 to K-15 of Krantz (1991) and ranges from 3.0 to 2.8 Ma. Blackwelder (1981) estimated the age at 2.5 Ma and Krantz (1991) at 2.1 Ma.

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

Chesapeake Group on the State map is used undivided. However, its formations--Chowan River, Yorktown, Eastover, St. Marys, Choptank, and Calvert--are described in the text. Chowan River contains a gray to dusky blue-green sand, fine- to medium-grained, clayey and silty, commonly very shelly. The sand grades laterally into laminated, silty clay and upward into cross-bedded, biofragmental sand, clayey silt, and silty clay. Discontinuous pebbly to bouldery sand is present at very irregular base of unit. Mollusks include GLYCYMERIS HUMMI, NOETIA CAROLINENSIS, and CAROLINAPECTEN EBOREUS BERTIENSIS. Thickness is 0 to 50 ft. Recognized only in southeasternmost VA and NC. Members not discussed. Age is late Pliocene.

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

Chowan River Formation, in the Aurora district, NC, is a gray, clayey, fossiliferous coarse quartz sand. It is intermittently indurated and contains abundant pebble to cobble sized clumps that have been cemented by calcium carbonate. Called "boulder bed" by miners. Irregular in thickness and laterally discontinuous. Exposure in Lee Creek Mine is probably Edenhouse Member. Chowan River unconformably overlies the Yorktown Formation and unconformably underlies the James City Formation. Age is late Pliocene.

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