St. Marys 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:

Genus	Species	Notes	Tooth example	Ref.
Notorynchus	N. primigenius	This species is possibly synonymous with the broadnose sevengill shark.
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.
Carcharhinus	C. leucas	Commonly known as the bull shark
Carcharhinus	C. perezii	Commonly known as the Caribbean reef shark
Carcharhinus	C. priscus	An extinct requiem shark
Carcharhinus	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

Genus	Species	Notes	Image	Ref.
Thecachampsa	T. antiquus	A Tomistominae