Demopolis Chalk Formation

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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]

A cretoxyrhinid

Squalicorax sp.

Scapanorhynchus

Scapanorhynchus sp.[2]

A mitsukurinid

Squalicorax

S. kaupi

Anacoracids

S. pristodontus[2]

Ischyrhiza

I. mira[2]

A sclerorhynchid

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 xiphiid

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

P. primaevus[5]

A plioplatecarpine

Prognathodon

P. rapax

A mosasaurine

P. solvayi[2]

Plesiosaurs[edit]

Plesiosaurs of the Demopolis Chalk
Genus Species Presence Notes Images

Elasmosaurus

Elasmosaurus sp.[2]

An elasmosaurid

Elasmosaurus sp.

See also[edit]

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 k 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.