St. Marys Formation Explained

St. Marys Formation
Type:	Formation
Age:	Neogene
Period:	Neogene
Region:
Unitof:	Chesapeake Group
Underlies:	Eastover Formation
Overlies:	Choptank Formation

The St. Marys Formation is a geologic formation in Maryland and Virginia, United States. It preserves fossils dating back to the Miocene Epoch of the Neogene period. It is the youngest Miocene formation present in the Calvert Cliffs and is part of the Chesapeake Group.

Vertebrate paleofauna

A diverse vertebrate paleofauna is known from the St. Marys Formation:

Cartilaginous fish!Genus!Species!Notes!Tooth example!Ref.

Notorynchus	N. primigenius	This species is possibly synonymous with the broadnose sevengill shark.		^[1]
Hexanchus	H. gigas	A species of cow shark. This species is extremely rare in this formation.
Squalus		Commonly known as the spurdog.
Squatina		Commonly known as the angel shark.
Rhincodon	R. typus	Commonly known as the whale shark. This species is extremely rare in this formation.
Carcharodon	C. hastalis	Putative ancestor to the extant great white shark
Carcharomodus	C. escheri	Commonly known as Escher's mako. It is also known as Carcharodon subserratus and is sometimes placed in Isurus. It is extremely rare in this formation.
Otodus	O. megalodon	This is the largest shark known to have existed.
Alopias	A. latidens	This species may be synonymous with the extant common thresher shark.
Mustelus		Commonly known as smooth-hounds
Hemipristis	H. serra	Commonly known as the snaggletooth shark. It is related to the extant snaggletooth shark.
Carcharhinus	C. falciformus	Commonly known as the silky shark.
	C. leucas	Commonly known as the bull shark
	C. perezii	Commonly known as the Caribbean reef shark
	C. priscus	An extinct requiem shark
	C. plumbeus	Commonly known as the sandbar shark
Negaprion	N. brevrostris	Commonly known as the lemon shark
Rhizoprionodon		Commonly known as the sharpnose shark
Pteromylaeus		Commonly known as the bull ray
Aetobatus		Commonly known as the eagle ray

Bony fish!Genus!Notes!Image!Ref.

Acipenseridae gen. indet.
Lepisosteus
Amia	cf. A. calva
Alosa
Ictalurus
Merluccius
Belone	B. countermani		^[2]
Prionotus
Agonidae gen. indet.
"Paralbula"	"P." dorisiae
Lagodon
Stenotomus
Pogonias
Sciaenops
Tautoga
Astroscopus	A. countermani		^[3]
Sphyraena
Istiophoridae gen. indet.

Reptiles!Genus!Species!Notes!Image!Ref.

Thecachampsa

T. antiquus

A Tomistominae

Sea mammals!Type!Genus!Species!Notes!Image!Ref.

Sirenians (sea cows)	Metaxytherium	M. floridanum
Cetaceans (whales, dolphins and porpoises)	Aulophyseter	A. mediatlanticus	A sperm whale		^[4]
	Lophocetus	L. calvertensis			^[5]
	Messapicetus				^[6]
	Stenasodelphis	S. russellae			^[7]

Terrestrial mammals!Name!Notes!Images!Ref.

Procamelus	cf. P. minor		^[8]
Desmathyus
Tapirus
Neohipparion lenticulare
Equidae indet.	Larger than Parahippus
Rhinoceratidae
Cormohipparion

See also

• List of fossiliferous stratigraphic units in Virginia
• Paleontology in Virginia

External links

• Web site: Fossilworks: Gateway to the Paleobiology Database. ((Various Contributors to the Paleobiology Database)). 17 December 2021.

Notes and References

1. 2018-09-25. Godfrey. Stephen J.. The Geology and Vertebrate Paleontology of Calvert Cliffs, Maryland, USA. Smithsonian Contributions to Paleobiology. 100. 2–274. 10.5479/si.1943-6688.100. 1943-6688. free.
2. de Sant'Anna, V. B., Collette, B. B., & Godfrey, S. J. (2013). † Belone countermani, a new Miocene needlefish (Belonidae) from the St. Marys Formation of Calvert Cliffs, Maryland. Proceedings of the Biological Society of Washington, 126 (2), 137-150.
3. Carnevale. Giorgio. Godfrey. Stephen J.. Pietsch. Theodore W.. 2011-11-01. Stargazer (Teleostei, Uranoscopidae) cranial remains from the Miocene Calvert Cliffs, Maryland, U.S.A. (St. Marys Formation, Chesapeake Group). Journal of Vertebrate Paleontology. 31. 6. 1200–1209. 10.1080/02724634.2011.606856. 196608143 . 0272-4634.
4. http://www.fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=36673 Aulophyseter
5. Fuller. Anna J.. Godfrey. Stephen J.. 2007-06-12. https://doi.org/10.1671/0272-4634(2007)27[535:ALMZMS2.0.CO;2 A late Miocene ziphiid (Messapicetus sp.: Odontoceti: Cetacea) from the St. Marys Formation of Calvert Cliffs, Maryland]. Journal of Vertebrate Paleontology. 27. 2. 535–540. 10.1671/0272-4634(2007)27[535:ALMZMS]2.0.CO;2. 85606021 . 0272-4634.
6. Fuller. Anna J.. Godfrey. Stephen J.. 2007-06-12. http://dx.doi.org/10.1671/0272-4634(2007)27[535:almzms2.0.co;2 A late Miocene ziphiid (Messapicetus sp.: Odontoceti: Cetacea) from the St. Marys Formation of Calvert cliffs, Maryland]. Journal of Vertebrate Paleontology. 27. 2. 535–540. 10.1671/0272-4634(2007)27[535:almzms]2.0.co;2. 85606021 . 0272-4634.
7. Godfrey. Stephen J.. Barnes. Lawrence G.. 2008-06-12. https://doi.org/10.1671/0272-4634(2008)28[520:ANGASO2.0.CO;2 A new genus and species of late Miocene pontoporiid dolphin (Cetacea: Odontoceti) from the St. Marys Formation in Maryland]. Journal of Vertebrate Paleontology. 28. 2. 520–528. 10.1671/0272-4634(2008)28[520:ANGASO]2.0.CO;2. 86216551 . 0272-4634.
8. Eshelman, R. Terrestrial Mammal Remains from the Miocene Chesapeake Group of Calvert Cliffs, Maryland, and Comparisons With Miocene.