Molluscan Zone 7, Cobham Bay Mbr, Eastover Fm - Sunken Meadow Creek (Miocene of the United States)

Where: Surry County, Virginia (37.2° N, 76.9° W: paleocoordinates 37.4° N, 75.2° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Cobham Bay Member (Eastover Formation), Late/Upper Miocene (11.6 - 5.3 Ma)

• Unit B in Ward 1992 (Fig. 11), ~0.5 m of sand. Collection from Cobham Bay Mbr of Eastover Fm, which overlies a thick unit of Claremont Manor Mbr, Eastover Fm and underlies the Rushmere Mbr of the Yorktown Fm.

• bed-level stratigraphic resolution

Environment/lithology: coastal; unlithified, phosphatic, shelly/skeletal sandstone

• Accumulated during transgression; product of only brief period of sedimentation or of erosion; basin conditions interpreted as being open marine, shallow shelf with normal salinities.
• Sand, shelly, fine, slightly phosphatic.

Size class: macrofossils

Reposited in the USNM

• Most material appears to be reposited in USNM and USGS collections

Primary reference: L. W. Ward. 1992. Molluscan biostratigraphy of the Miocene Middle Atlantic Coastal Plain of North America. Virginia Museum of Natural History 2 [A. Miller/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 59296: authorized by Austin Hendy, entered by Austin Hendy on 25.03.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• Probably not exhaustive, but a summary of the common and abundant forms from unit. Modern nomenclature utilized with species level assignments.
Gastropoda
 Neogastropoda - Muricidae
Ecphora kochi Ward and Gilinsky 1988 murex snail
 Cerithioidea - Turritellidae
"Turritella plebeia" = Mariacolpus plebeia
"Turritella plebeia" = Mariacolpus plebeia Say 1824 turret shell
Subspecies: T. plebeia plebeia
Bivalvia
 Carditida - Astartidae
Astarte cobhamensis Ward 1992 clam
Astarte rappahannockensis Gardner 1943 clam
 Carditida - Crassatellidae
 Cardiida - Mactridae
"Spisula" rappahannockensis Gardner 1944 clam
 Cardiida - Veneridae
Mercenaria druidi Ward 1992 quahog
Lirophora vredenburgi Ward 1992 venus clam
 Cardiida - Euloxidae
 Arcida - Glycymerididae
Costaglycymeris mixoni Ward 1992 clam
 Arcida - Arcidae
Striarca centenaria Say 1824 clam
Rasia arata Say 1824 ark
 Ostreida - Malleidae
 Ostreida - Ostreidae
Ostrea compressirostra Say 1824 oyster
Subspecies: O. compressirostra geraldjohnsoni
 Pectinida - Pectinoidae
Chesapecten middlesexensis Mansfield 1936 scallop
Subspecies: C. middlesexensis middlesexensis
Dallarca carolinensis
  -
Dallarca carolinensis Conrad 1849
Subspecies: D. carolinensis carolinensis