Choptank Formation

The Choptank Formation is a geologic formation in Virginia and Maryland. It preserves fossils dating from the Miocene epoch of the Neogene period.

Choptank Formation
Stratigraphic range: Miocene
Chesapecten nefrens, Choptank Formation
Type	Formation
Unit of	Chesapeake Group
Underlies	St. Marys Formation
Overlies	Calvert Formation
Location
Region	Virginia, Maryland
Country	United States
Type section
Named for	Choptank River

Fossils

The Choptank Formation is extremely fossiliferous. Some of the fossil species represented include the following:^[1][2]

Sharks

• Otodus megalodon
• Carcharodon hastalis
• Isurus oxyrhincus
• Carcharomodus escheri
• Physogaleus contortus
• Galeocerdo aduncus
• Carcharhinus
• Hemipristis serra
• Squatina sp.
• Notorhyncus cepedianus
• Carcharias
• Isurus retroflexus
• Parotodus benedeni
• Alopias vulpinus
• Alopias grandis
• Cetorhinus
• Negaprion brevirostris
• Rhizoprionodon
• Sphryna laevissima

Rays and Other Cartilaginous Fish

• Aetobatus arcuatus
• Pteromyaleus sp.
• Dasyatis rugosa
• Dasyatis probsti
• Pinthicus stenodon

Fish

• Acipenseridae indet.
• Opsanus sp.
• Serranidae sp.
• Pogonias sp.
• Sciaenops sp.
• Tautoga sp.
• Acanthocybium cf. solandri
• Thunnus sp.
• Istiophorus cf. platypterus
• Mola cf. pileata
• Ariopsis aff. A. felis
• Trisopterus sculptus
• Micromesistius cognatus
• Prionotus

Cetaceans

• Aglaocetus sp.
• Cetotherium sp.
• Delphinodon sp.
• Eurhinodelphis sp.
• Macrokentriodon morani
• Mesocetus
• Parietobalaena
• Orycterocetus
• Pelocetus

Pinnipeds

• Callophoca obscura
• Leptophoca proxima
• Prophoca sp.

Crocodilians

• Thecachampsa antiquus
• Thecachampsa sericodon

Invertebrates

• Chesapecten nefrens
• Chesacardium
• Euspira heros
• Mariacolpus octonnaria
• Macrocallista marylandica
• Stewartia anodonta
• Marvacrassitella marylandica
• Ecphora
• Panopea
• Albertella aberti

^[3]

Terrestrial Mammals

• Cynarctus wangi
• Gomphotherium calvertensis
• Hipparion cf. phosphorum

See also

• List of fossiliferous stratigraphic units in Virginia
• Paleontology in Virginia
• Paleontology in Maryland
• Calvert Cliffs State Park
• List of fossiliferous stratigraphic units in Maryland
• Chesapeake Group

References

1. Godfrey, Stephen J., ed. (2018-09-25). "The Geology and Vertebrate Paleontology of Calvert Cliffs, Maryland, USA". Smithsonian Contributions to Paleobiology (100): 2–274. doi:10.5479/si.1943-6688.100. ISSN 1943-6688.
2. "Paleobiology Collections Search". collections.nmnh.si.edu. Retrieved 2020-08-14.
3. "Collections". The Fossil Forum. Retrieved 2020-08-14.

• Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.