Hellen Creek, Zone 20 (Miocene of the United States)

Where: Calvert County, Maryland (38.4° N, 76.5° W: paleocoordinates 38.5° N, 73.6° W)

• coordinate estimated from map

When: Conoy Member (Choptank Formation), Serravallian (13.8 - 11.6 Ma)

Environment/lithology: marine; fine-grained, argillaceous, sandy siltstone

• Silt; clayey, slightly sandy, blocky, laminated with thin sand partings

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: general faunal/floral analysis

PaleoDB collection 71639: authorized by Mark Uhen, entered by Mark Uhen on 02.05.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

Gastropoda
 Cerithioidea - Turritellidae
"Turritella plebeia" = Mariacolpus plebeia
"Turritella plebeia" = Mariacolpus plebeia Say 1824 turret shell
subspecies plebeia
Bivalvia
 Cardiida - Veneridae
Mercenaria cuneata Conrad 1869 quahog