Demopolis Chalk Formation

Demopolis Chalk Formation 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
Named for	Demopolis, Alabama
Region	Alabama, Mississippi, Tennessee
Country	United States

The Demopolis Chalk Formation 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 Formation.^[2][3]

Vertebrate paleofauna

Fish

Cartilaginous fish

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

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

Dinosaurs

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

Mosasaurs of the Demopolis Chalk Formation
Genus	Species	Presence	Notes	Images
Mosasaurus	M. conodon[2]		A mosasaurine	Prognathodon
Plioplatecarpus	P. primaevus[5]		A plioplatecarpine
Prognathodon	P. rapax		A mosasaurine
	P. solvayi[2]

Plesiosaurs

Plesiosaurs of the Demopolis Chalk Formation
Genus	Species	Presence	Notes	Images
Elasmosaurus	Elasmosaurus sp.[2]		An elasmosaurid	Elasmosaurus sp.

See also

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

References

	Earth sciences portal
	Paleontology portal
	Dinosaurs portal

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. http://www.bioone.org/doi/full/10.1671/0272-4634(2002)022%5B0091%3ASDAHSO%5D2.0.CO%3B2. 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. http://www.oceansofkansas.com/mus-plat.html. Retrieved 2009-02-02.