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 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.[2][3]

## Vertebrate paleofauna

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### Fish

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#### Cartilaginous fish

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Cartilaginous fish of the Demopolis Chalk Formation

Genus  | Species  | Presence  | Notes  | Images

Chimaeriformes indet.[4]

|  |

Alabama[4]

|  |  Ischyrhiza mira rostral spines Teeth of Scapanorhynchus texanus Squalicorax sp.

Cretolamna

C. appendiculata[2][4]

Alabama[4]

An otodontid

Ischyrhiza

I. mira[2][4]

Alabama[4]

A sclerorhynchid

Scapanorhynchus

S. texanus[4]

Alabama[4]

A mitsukurinid

Serratolamna

S. serrata?[4]

Alabama[4]

A lamniform shark

Squalicorax

S. kaupi[4]

Alabama[4]

Anacoracids

S. pristodontus[2][4]

S. sp.[4]

#### Bony fish

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Bony fish of the Demopolis Chalk Formation

Genus  | Species  | Presence  | Notes  | Images

Enchodus

E. ferox[4]

Alabama[4]

Enchodontids

|  Enchodus petrosus Protosphyraena Stratodus

E. gladiolus[4]

E. petrosus[4]

Protosphyraena

P. sp.[4]

Alabama[4]

A pachycormiform

Saurodon

S. sp.[4]

Alabama[4]

An ichthyodectiform

Stratodus

S. sp.[4]

Alabama[4]

An aulopiform

Xiphactinus

X. vetus[5]

|  |

An ichthyodectid

### Reptiles

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#### Dinosaurs

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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

#### Crocodylians

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Crocodylians of the Demopolis Chalk Formation

Genus  | Species  | Presence  | Notes  | Images

Borealosuchus

B. sp.[4]

Alabama[4]

An eusuchian

|  Borealosuchus skull

#### Mosasaurs

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Mosasaurs of the Demopolis Chalk

Genus  | Species  | Presence  | Notes  | Images

Clidastes

C. propython[4]

Alabama[4]

A mosasaurine

|  Clidastes propython Plioplatecarpus

Halisaurus

H. sp.[4]

Alabama[4]

A halisaurine

Mosasaurus

M. conodon[2][4]

Alabama[4]

A mosasaurine

M. cf. missouriensis[4]

Platecarpus

P. cf. somenensis[4]

Alabama[4] and Mississippi[6]

A plioplatecarpine

Plioplatecarpus

P. sp. nov.[7]

| Mississippi[6] |

A plioplatecarpine

Tylosaurus

T. sp.[4]

Alabama[4] and Mississippi[6]

A tylosaurine

#### Turtles

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Turtles of the Demopolis Chalk

Genus  | Species  | Presence  | Notes  | Images

Asmodochelys

A. parhami[8]

Geographically present in Alabama and Mississippi.[8]

A marine ctenochelyid turtle

|  Protostega gigas

Chedighaii

C. barberi[4]

Alabama[4]

A bothremydid

Ctenochelys

C. cf. tennuitesta[4]

Alabama[4]

A ctenochelyid

Prionochelys

P. matutina?[4]

Alabama[4]

A ctenochelyid

Protostega

P. gigas[4]

Alabama[4]

A protostegid

## See also

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* Paleontology portal
* Dinosaurs portal

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

## References

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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\. doi:10.1671/0272-4634(2005)025[0119:ANGASO]2.0.CO;2. S2CID 86243316.119-143&rft.date=2005&rft_id=info:doi/10.1671/0272-4634(2005)025[0119:ANGASO]2.0.CO;2&rft_id=https://api.semanticscholar.org/CorpusID:86243316#id-name=S2CID&rft.aulast=Carr&rft.aufirst=T.D.&rft.au=Williamson,+T.E.&rft.au=Schwimmer,+D.R.&rfr_id=info:sid/en.wikipedia.org:Demopolis+Chalk" class="Z3988">
2. ^ a b c d e f 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 2024-06-12.91-103&rft.date=2002&rft_id=info:doi/10.1671/0272-4634(2002)022[0091:SDAHSO]2.0.CO;2&rft.aulast=Kiernan&rft.aufirst=Caitlin+R.&rft_id=https://www.researchgate.net/publication/254314199&rfr_id=info:sid/en.wikipedia.org:Demopolis+Chalk" class="Z3988">
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. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as 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): 46–71.46-71&rft.date=2013&rft.au=Ikejiri,+T.&rft.au=Ebersole,+J.A.&rft.au=Blewitt,+H.L.&rft.au=Ebersole,+S.M.&rft_id=https://www.researchgate.net/publication/272508435&rfr_id=info:sid/en.wikipedia.org:Demopolis+Chalk" class="Z3988">
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:10.1080/02724634.1997.10011007.610-615&rft.date=1997&rft_id=info:doi/10.1080/02724634.1997.10011007&rft.aulast=Schwimmer&rft.aufirst=D.+R.&rft.au=Stewart,+J.+D.&rft.au=Williams,+G.+Dent&rft_id=https://www.researchgate.net/publication/254314020&rfr_id=info:sid/en.wikipedia.org:Demopolis+Chalk" class="Z3988">
6. ^ a b c 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.10472410.79-90&rft.date=2024-01-09&rft_id=info:doi/10.5281/zenodo.10472410&rft.aulast=Rempert&rft.aufirst=Trevor+H&rft.au=Martens,+Brennan+P&rft.au=Vinkeles+Melchers,+Alexander+P.+M.&rft_id=https://zenodo.org/records/10472410&rfr_id=info:sid/en.wikipedia.org:Demopolis+Chalk" class="Z3988">
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.
8. ^ a b 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): Article ID 191950. Bibcode:2019RSOS....691950G. doi:10.1098/rsos.191950. PMC 6936288. PMID 31903219.