Demopolis Chalk

Geological formation in the United States

Demopolis Chalk

Stratigraphic range: Upper Cretaceous
Type| Geological formation
Unit of| Selma Group
Sub-units| Bluffport Marl Member
Underlies| Ripley Formation
Overlies| Mooreville Chalk Formation
Lithology
Primary| Chalk
Location
Region| Alabama, Mississippi, Tennessee
Country| United States
Type section
Named for| Demopolis, Alabama

The Demopolis Chalk is a geological formation in North America, within the U.S. states of Alabama, Mississippi, and Tennessee. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment during the middle Campanian stage of the Late Cretaceous.[1] It is a unit of the Selma Group and consists of the upper Bluffport Marl Member and a lower unnamed member.[2] Dinosaur and mosasaur remains are among the fossils that have been recovered from the Demopolis Chalk.[2][3]

## Vertebrate paleofauna[edit]

### Fish[edit]

#### Cartilaginous fish[edit]

Cartilaginous fish of the Demopolis Chalk Formation

Genus  | Species  | Presence  | Notes  | Images

Cretolamna

C. appendiculata[2]

|  |

An Otodontid

|  Squalicorax sp.

Scapanorhynchus

Scapanorhynchus sp.[2]

|  |

A mitsukurinid

Squalicorax

S. kaupi

|  |

Anacoracids

S. pristodontus[2]

Ischyrhiza

I. mira[2]

|  |

A sclerorhynchid

Carcharias

C. samhammeri

|  |

A Odontaspidid

Archaeolamna

A. "kopingensis"

|  |

A Archaeolamnid

#### Bony fish[edit]

Bony fish of the Demopolis Chalk Formation

Genus  | Species  | Presence  | Notes  | Images

Enchodus

E. petrosus[2]

|  |

An enchodontid

|  Enchodus petrosus

Protosphyraena

P. gladius[2]

|  |

A pachycormid

Xiphactinus

X. vetus[4]

|  |

An ichthyodectid

### Reptiles[edit]

#### Dinosaurs[edit]

Indeterminate hadrosaurid remains have been found in Tennessee.[3] Possible indeterminate tyrannosaurid remains have been found in Alabama.[3]

Dinosaurs of the Demopolis Chalk Formation

Genus  | Species  | Presence  | Notes  | Images

Appalachiosaurus[1][3]

A. montgomeriensis[1][3]

Geographically present in Alabama.[3]

A tyrannosauroid

|  Appalachiosaurus

#### Mosasaurs[edit]

Mosasaurs of the Demopolis Chalk

Genus  | Species  | Presence  | Notes  | Images

Mosasaurus

M. conodon[2]

|  |

A mosasaurine

|  Plioplatecarpus

Plioplatecarpus

P. primaevus[5]

|  |

A plioplatecarpine

Prognathodon

P. cf. rapax

|  |

A mosasaurine

#### Plesiosaurs[edit]

Plesiosaurs of the Demopolis Chalk

Genus  | Species  | Presence  | Notes  | Images

Elasmosaurus

Elasmosaurus sp.[2]

|  |

An elasmosaurid

|  Elasmosaurus sp.

## See also[edit]

* Paleontology portal
* Dinosaurs portal

* List of dinosaur-bearing rock formations
* List of fossil sites

## References[edit]

1. ^ a b c Carr, T.D., Williamson, T.E., & Schwimmer, D.R. 2005. A new genus and species of tyrannosauroid from the Late Cretaceous (middle Campanian) Demopolis Formation of Alabama. Journal of Vertebrate Paleontology 25(1): 119–143.
2. ^ a b c d e f g h i j Kiernan, Caitlin R. (2002). "Stratigraphic distribution and habitat segregation of mosasaurs in the Upper Cretaceous of western and central Alabama, with an historical review of Alabama mosasaur discoveries". Journal of Vertebrate Paleontology. 22 (1): 91–103. doi:10.1671/0272-4634(2002)022[0091:SDAHSO]2.0.CO;2. Retrieved 2009-02-02.
3. ^ a b c d e f Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 574-588. ISBN 0-520-24209-2.
4. ^ Schwimmer, D. R.; Stewart, J. D.; Williams, G. Dent (1997). "Xiphactinus vetus and the Distribution of Xiphactinus Species in the Eastern United States". Journal of Vertebrate Paleontology. 17 (3): 610–615. doi:10.1080/02724634.1997.10011007.
5. ^ Everhart, Mike (2008-04-18). "The Platecarpus Collection: A virtual collection of Platecarpus specimens from Kansas and elsewhere". Oceans of Kansas Paleontology. Retrieved 2009-02-02.