Named as a member of Eastover Formation. Named for exposures along James River below Upper Chippokes Creek near Claremont Manor, Surry Co., southeastern VA. Occurs in Coastal Plain of VA and overlaps slightly into southeastern MD. Consists of greenish-gray, tan-weathering (iron stained), coarse- to fine-grained, poorly sorted clayey sand fining upward to clay. Thickness is 24 m at Claremont, 9 m at type section. Unconformably overlies St. Marys Formation (or progressively older sediments to the south); unconformably underlies Cobham Bay Member (new) of Eastover. Age is early late Miocene (early Tortonian) is constrained by K-Ar age of 8.7+/-0.4 Ma for glauconite from overlying Cobham Bay Member and an age of 12.0+/-0.5 Ma for glauconite from underlying St. Marys Formation. Various workers have indicated dissatisfaction with glauconite as a basis for radiometric dates and they may be too young, but Tortonian still seems likely. Also contains sparse mollusk assemblages including SCAPHARCA CAROLENSIS (Dall, 1897), S. CLISEA (Dall, 1898), S. sp., S. VIRGINIAE (Dall, 1897), GLYCYMERIS VIRGINIAE (Dall, 1897), ISOGNOMON sp., CHESAPECTEN MIDDLESEXENSIS (Mansfield, 1836), OSTREA sp., LUCINOMA CONTRACTA (Say, 1824), CRASSATELLA SURRYENSIS (Mansfield, 1928), CARDIUM LAQUEATUM ssp., EULOXIA LATISULCATA (Conrad, 1839), GLOSSUS FRATERNA (Say, 1824), DOSINIA ACETABULUM (Conrad, 1832), LIROPHORA DALLI (Olsson, 1914), MERCENARIA sp., and several others.

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

Claremont Manor Member of Eastover Formation shown on correlation chart of Miocene stratigraphic units in MD, VA, and NC, while Cobham Bay Member shown in only VA and NC.

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