Formation · Neogene
Calvert Formation
Miocene unit, Maryland · Virginia
The Calvert Formation exposed at Calvert Cliffs, Maryland, is the classic Miocene shark-tooth locality of the eastern United States: megalodon, mako (Carcharodon hastalis), Hemipristis, tiger and cow-shark teeth wash out onto the beaches, along with whale bone, crocodile teeth, Chesapecten scallops and the Maryland state fossil Ecphora. Beach teeth are usually grey to black and river-worn; large, complete Calvert megalodons are scarce and valued accordingly.
| Country | United States |
|---|---|
| Region | Maryland, Virginia |
| Age | Burdigalian, Miocene |
| Age range | ~18–14 Ma |
| Group | Chesapeake Group |
| Macrostrat rank | Fm· Macrostrat |
| Macrostrat age | 24.1–11.6 Ma· Macrostrat |
| Lithology | sand, clay, silt, diatomite· Macrostrat |
| Environment | shoreface, offshore, estuary/bay, marine, marginal marine· Macrostrat |
| Macrostrat columns | 8 column(s) sampled from 8 unit(s)· Macrostrat |
| Members (Macrostrat) | Calvert Beach· Macrostrat |
| PBDB collections | 150 collections, 1350 occurrences· Paleobiology Database |
Collecting and legality
Calvert Cliffs State Park and the public beaches allow surface collecting on the beach only; digging or climbing the cliffs is prohibited and dangerous, and most cliff frontage is private. Scientists' Cliffs and other communities restrict access. Finds from the beach are yours to keep and sell.
Lithology and setting
Fossiliferous marine sands, silts and diatomaceous clays of the Chesapeake Group, exposed in cliffs up to 30 m along the western shore of Chesapeake Bay.
Commonly recorded taxa (PBDB)
Genera most often recorded from this unit in the Paleobiology Database (first 200 occurrences): Galeocerdo (6), Astarte (4), Carcharias (4), Odontoceti (4), Sphyrna (4), Archaeohippus (3), Brevirostrodelphis (3), Hadrodelphis (3), Myliobatis (3), Placopecten (3), Raphoneis (3), Squalodon (3), Stirtonhyus (3), Tayassuidae (3), Zarhachis (3).
Source: Paleobiology Database
Elsewhere
- Macrostrat: 288
- macrostratConcept: 793
- PBDB: strata:Calvert
- Wikidata: Q104848829
- Macrostrat stratigraphic name
- PBDB occurrences for this unit
- Wikipedia: Calvert Formation
- Mindat: Calvert Formation
Cite this article
Stratum Study. "Calvert Formation" (Formation). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/formations/calvert-formation. Accessed 2026-09-20.
@misc{stratum-calvert-formation,
title = {Calvert Formation},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/formations/calvert-formation}},
year = {2026},
note = {Formation article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, macrostrat, pbdb, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.