St. Marys Formation
Geologic formation in United States
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The St. Marys Formation is a geologic formation in Maryland and Virginia, United States. It preserves fossils dating back to the Tortonian stage of the Late Miocene epoch of the Neogene period (11 to 8 million years ago).[1] It is the youngest Miocene formation present in the Calvert Cliffs and is part of the Chesapeake Group.
| St. Marys Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Formation |
| Unit of | Chesapeake Group |
| Underlies | Eastover Formation |
| Overlies | Choptank Formation |
| Location | |
| Region | Maryland, Virginia |
| Country | United States |
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. |  |
[2] |
| Hexanchus | H. gigas | A species of cow shark. This species is extremely rare in this formation. |  |
[2] |
| Squalus | Commonly known as the spurdog. | [2] | ||
| Squatina | Commonly known as the angel shark. | [2] | ||
| Rhincodon | R. typus | Commonly known as the whale shark. This species is extremely rare in this formation. |  |
[2] |
| Carcharodon | C. hastalis | Putative ancestor to the extant great white shark |  |
[2] |
| 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. |  |
[2] |
| Otodus | O. megalodon | This is the largest shark known to have existed. |  |
[2] |
| Alopias | A. latidens | This species may be synonymous with the extant common thresher shark. |  |
[2] |
| Mustelus | Commonly known as smooth-hounds | [2] | ||
| Hemipristis | H. serra | Commonly known as the snaggletooth shark. It is related to the extant snaggletooth shark. |  |
[2] |
| Carcharhinus | C. falciformus | Commonly known as the silky shark. |  |
[2] |
| C. leucas | Commonly known as the bull shark |  |
[2] | |
| C. perezii | Commonly known as the Caribbean reef shark |  |
[2] | |
| C. priscus | An extinct requiem shark | [2] | ||
| C. plumbeus | Commonly known as the sandbar shark |  |
[2] | |
| Negaprion | N. brevrostris | Commonly known as the lemon shark |  |
[2] |
| Rhizoprionodon | Commonly known as the sharpnose shark | [2] | ||
| Pteromylaeus | Commonly known as the bull ray | [2] | ||
| Aetobatus | Commonly known as the eagle ray | [2] |
| Genus | Notes | Image | Ref. |
|---|---|---|---|
| Acipenseridae gen. indet. | .jpg) |
[2] | |
| Lepisosteus |  |
[2] | |
| Amia | cf. A. calva | .jpg) |
[2] |
| Alosa |  |
[2] | |
| Ictalurus |  |
[2] | |
| Merluccius |  |
[2] | |
| Belone | B. countermani |  |
[2][3] |
| Prionotus | .jpg) |
[2] | |
| Agonidae gen. indet. |  |
[2] | |
| "Paralbula" | "P." dorisiae | [2] | |
| Lagodon | _(12598284094).jpg) |
[2] | |
| Stenotomus | _(12592129064).jpg) |
[2] | |
| Pogonias |  |
[2] | |
| Sciaenops | _(12527956414).jpg) |
[2] | |
| Tautoga | _(15611353592).jpg) |
[2] | |
| Astroscopus | A. countermani |  |
[4][2] |
| Sphyraena |  |
[2] | |
| Istiophoridae gen. indet. |  |
[2] |
| Genus | Species | Notes | Image | Ref. |
|---|---|---|---|---|
| Thecachampsa | T. antiquus | A Tomistominae |  |
[2] |
| Type | Genus | Species | Notes | Image | Ref. |
|---|---|---|---|---|---|
| Sirenians (sea cows) | Metaxytherium | M. floridanum |  |
[2] | |
| Cetaceans (whales, dolphins and porpoises) | Aulophyseter | A. mediatlanticus | A sperm whale |  |
[5] |
| Lophocetus | L. calvertensis | [6] | |||
| Messapicetus |  |
[7] | |||
| Stenasodelphis | S. russellae | [8] |
| Name | Notes | Images | Ref. |
|---|---|---|---|
| Procamelus | cf. P. minor |  |
[9] |
| Desmathyus | [9] | ||
| Tapirus | .JPG) |
[9] | |
| Neohipparion lenticulare | _(17322549474).jpg) |
[9] | |
| Equidae indet. | Larger than Parahippus | [9] | |
| Rhinoceratidae | [9] | ||
| Cormohipparion |  |
[9] |
