Demopolis Chalk

Demopolis Chalk
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 age 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.²³

Vertebrate paleofauna

Fish

Cartilaginous fish

Cartilaginous fish of the Demopolis Chalk Formation
Genus	Species	Presence	Notes	Images
Chimaeriformes indet.⁴		Alabama⁴		Ischyrhiza mira rostral spines source ↗ Teeth of Scapanorhynchus texanus source ↗ Squalicorax sp. source ↗
Cretolamna	C. appendiculata²⁴	Alabama⁴	An otodontid
Ischyrhiza	I. mira²⁴	Alabama⁴	A sclerorhynchid
Scapanorhynchus	S. texanus⁴	Alabama⁴	A mitsukurinid
Serratolamna	S. serrata?⁴	Alabama⁴	A lamniform shark
Squalicorax	S. kaupi⁴	Alabama⁴	Anacoracids
	S. pristodontus²⁴
	S. sp.⁴

Bony fish

Bony fish of the Demopolis Chalk Formation
Genus	Species	Presence	Notes	Images
Enchodus	E. ferox⁴	Alabama⁴	Enchodontids	Enchodus petrosus source ↗ Protosphyraena source ↗ Stratodus source ↗
	E. gladiolus⁴
	E. petrosus⁴
Protosphyraena	P. sp.⁴	Alabama⁴	A pachycormiform
Saurodon	S. sp.⁴	Alabama⁴	An ichthyodectiform
Stratodus	S. sp.⁴	Alabama⁴	An aulopiform
Xiphactinus	X. vetus⁵		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
Appalachiosaurus¹³	A. montgomeriensis¹³	Geographically present in Alabama.³	A tyrannosauroid	Appalachiosaurus source ↗

Crocodylians

Crocodylians of the Demopolis Chalk Formation
Genus	Species	Presence	Notes	Images
Borealosuchus	B. sp.⁴	Alabama⁴	An eusuchian	Borealosuchus skull source ↗

Mosasaurs

Mosasaurs of the Demopolis Chalk
Genus	Species	Presence	Notes	Images
Clidastes	C. propython⁴	Alabama⁴	A mosasaurine	Clidastes propython source ↗ Plioplatecarpus source ↗
Halisaurus	H. sp.⁴	Alabama⁴	A halisaurine
Mosasaurus	M. conodon²⁴	Alabama⁴	A mosasaurine
Mosasaurus	M. cf. missouriensis⁴	Alabama⁴	A mosasaurine
Platecarpus	P. cf. somenensis⁴	Alabama⁴ and Mississippi⁶	A plioplatecarpine
Plioplatecarpus	P. sp. nov.⁷	Mississippi⁶	A plioplatecarpine
Tylosaurus	T. sp.⁴	Alabama⁴ and Mississippi⁶	A tylosaurine

Turtles

Turtles of the Demopolis Chalk
Genus	Species	Presence	Notes	Images
Asmodochelys	A. parhami⁸	Geographically present in Alabama and Mississippi.⁸	A marine ctenochelyid turtle	Protostega gigas source ↗
Chedighaii	C. barberi⁴	Alabama⁴	A bothremydid
Ctenochelys	C. cf. tennuitesta⁴	Alabama⁴	A ctenochelyid
Prionochelys	P. matutina?⁴	Alabama⁴	A ctenochelyid
Protostega	P. gigas⁴	Alabama⁴	A protostegid

References

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. doi:10.1671/0272-4634(2005)025[0119:ANGASO]2.0.CO;2. S2CID 86243316.
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 2024-06-12.
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.
Ikejiri, T.; Ebersole, J.A.; Blewitt, H.L.; Ebersole, S.M. (2013). "An Overview of Late Cretaceous Vertebrates from Alabama". Bulletin of the Alabama Museum of Natural History. 31 (1): 46–71.
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.
Rempert, Trevor H; Martens, Brennan P; Vinkeles Melchers, Alexander P. M. (2024-01-09). "New Mosasaur remains from the Upper Cretaceous of Mississippi". The Mosasaur - the Journal of the Delaware Valley Paleontological Society. 13: 79–90. doi:10.5281/zenodo.10472410.
Everhart, Mike (2008-04-18). "The Platecarpus Collection: A virtual collection of Platecarpus specimens from Kansas and elsewhere". Oceans of Kansas Paleontology. Archived from the original on 2024-03-17. Retrieved 2024-06-12.
Andrew D. Gentry; Jun A. Ebersole; Caitlin R. Kiernan (2019). "Asmodochelys parhami, a new fossil marine turtle from the Campanian Demopolis Chalk and the stratigraphic congruence of competing marine turtle phylogenies". Royal Society Open Science. 6 (12) 191950. Bibcode:2019RSOS....691950G. doi:10.1098/rsos.191950. PMC 6936288. PMID 31903219.

[TDCARR-1] 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. doi:10.1671/0272-4634(2005)025[0119:ANGASO]2.0.CO;2. S2CID 86243316.

[STRAT-2] 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 2024-06-12.

[cretaceousdistribution-3] 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.

[Kejiri2013-4] Ikejiri, T.; Ebersole, J.A.; Blewitt, H.L.; Ebersole, S.M. (2013). "An Overview of Late Cretaceous Vertebrates from Alabama". Bulletin of the Alabama Museum of Natural History. 31 (1): 46–71.

[XIPHAC-5] 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.

[:0-6] Rempert, Trevor H; Martens, Brennan P; Vinkeles Melchers, Alexander P. M. (2024-01-09). "New Mosasaur remains from the Upper Cretaceous of Mississippi". The Mosasaur - the Journal of the Delaware Valley Paleontological Society. 13: 79–90. doi:10.5281/zenodo.10472410.

[PLATE-7] Everhart, Mike (2008-04-18). "The Platecarpus Collection: A virtual collection of Platecarpus specimens from Kansas and elsewhere". Oceans of Kansas Paleontology. Archived from the original on 2024-03-17. Retrieved 2024-06-12.

[Gentry2019-8] Andrew D. Gentry; Jun A. Ebersole; Caitlin R. Kiernan (2019). "Asmodochelys parhami, a new fossil marine turtle from the Campanian Demopolis Chalk and the stratigraphic congruence of competing marine turtle phylogenies". Royal Society Open Science. 6 (12) 191950. Bibcode:2019RSOS....691950G. doi:10.1098/rsos.191950. PMC 6936288. PMID 31903219.

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