St. Marys Formation
Stratigraphic range: Neogene
Type	Formation
Unit of	Chesapeake Group
Underlies	Eastover Formation
Overlies	Choptank Formation
Location
Region	Maryland  Virginia
Country	United States

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.

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.		[1]
Squalus		Commonly known as the spurdog.		[1]
Squatina		Commonly known as the angel shark.		[1]
Rhincodon	R. typus	Commonly known as the whale shark. This species is extremely rare in this formation.		[1]
Carcharodon	C. hastalis	Putative ancestor to the extant great white shark		[1]
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.		[1]
Otodus	O. megalodon	This is the largest shark known to have existed.		[1]
Alopias	A. latidens	This species may be synonymous with the extant common thresher shark.		[1]
Mustelus		Commonly known as smooth-hounds		[1]
Hemipristis	H. serra	Commonly known as the snaggletooth shark. It is related to the extant snaggletooth shark.		[1]
Carcharhinus	C. falciformus	Commonly known as the silky shark.		[1]
	C. leucas	Commonly known as the bull shark		[1]
	C. perezii	Commonly known as the Caribbean reef shark		[1]
	C. priscus	An extinct requiem shark		[1]
	C. plumbeus	Commonly known as the sandbar shark		[1]
Negaprion	N. brevrostris	Commonly known as the lemon shark		[1]
Rhizoprionodon		Commonly known as the sharpnose shark		[1]
Pteromylaeus		Commonly known as the bull ray		[1]
Aetobatus		Commonly known as the eagle ray		[1]

Bony fish

Genus	Notes	Image	Ref.
Acipenseridae gen. indet.			[1]
Lepisosteus			[1]
Amia	cf. A. calva		[1]
Alosa			[1]
Ictalurus			[1]
Merluccius			[1]
Belone	B. countermani		[1][2]
Prionotus			[1]
Agonidae gen. indet.			[1]
"Paralbula"	"P." dorisiae		[1]
Lagodon			[1]
Stenotomus			[1]
Pogonias			[1]
Sciaenops			[1]
Tautoga			[1]
Astroscopus	A. countermani		[3][1]
Sphyraena			[1]
Istiophoridae gen. indet.			[1]

Reptiles

Genus	Species	Notes	Image	Ref.
Thecachampsa	T. antiquus	A Tomistominae		[1]

Sea mammals

Type	Genus	Species	Notes	Image	Ref.
Sirenians (sea cows)	Metaxytherium	M. floridanum			[1]
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			[8]
Tapirus			[8]
Neohipparion lenticulare			[8]
Equidae indet.	Larger than Parahippus		[8]
Rhinoceratidae			[8]
Cormohipparion			[8]

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

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

This article about a specific stratigraphic formation in Virginia is a stub. You can help Wikipedia by expanding it.

• v
• t
• e