Severn Formation Explained

Severn Formation
Type:	Geological formation
Period:	Maastrichtian

The Severn Formation is a Mesozoic geologic formation in Maryland. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.^[1]

Paleofauna

Dinosaurs

• "Coelosaurus" antiquus^[2]
• Ornithomimidae indet.^[3]
• Hadrosauridae indet.

Plesiosaurs

• Cimoliasaurus magnus

Mosasaurs

• Halisaurus platyspondylus^[4]
• Prognathodon rapax
• Mosasaurus hoffmanni
• Mosasaurus sp.
• cf. Mosasaurus conodon
• Mosasauridae indet.

• Deinosuchus rugosus
• Thoracosaurus neocesariensis
• Alligatorinae indet.

Turtles

• Peritresius ornatus
• Osteopygis emarginatus
• Trionyx priscus
• Toxochelyidae indet.

• Carcharias holmdelensis
• Carcharias samhammeri
• Chiloscyllium greeni
• Cretalamana appendiculata
• Dasyatis sp.
• Tomewingia problematica
• Galeorhinus garadoti
• Ginglymostoma sp.
• Heterodontus sp.
• Hybodus sp.
• Ischyrhiza cf. avonicola
• Ischyrhiza mira
• Myliobatis sp.
• Odontaspis aculeatus
• Plicatoscyllium antiquum
• Plicatoscyllium derameei
• Pseudohypolophus mcnultyi
• Ptychotrygon vermiculata
• Raja farishi
• Rhinobatos sp.
• Rhombodus binkhorsti
• Serratolamna serrata
• Squalicorax kaupi
• Squalicorax pristodontus
• Squatina hassei
• Ischyodus sp.

• Albuidae indet.
• Anomoedus cf. haseolus
• Cylinadracanthus sp.
• Egertonia sp.
• Enchodus ferox
• Hadrodus sp.
• Lepidosteus sp.
• Paralbula casei

See also

• List of dinosaur-bearing rock formations
  • List of stratigraphic units with few dinosaur genera

References

• Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. .

Notes and References

1. Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.
2. Baird . Donald . 1986 . Upper Cretaceous Reptiles from the Severn Formation of Maryland . The Mosasaur . 3 . 63–85.
3. Hartstien . Eugene F . Decina . Lawrence E . Keil . Ronald F . 1999 . A Late Cretaceous (Severn Formation) Vertebrate Assemblage from Bowie, Maryland . The Mosasaur . 6 . 17–23.
4. Holmes. Robert B.. Sues. Hans-Dieter. A Partial Skeleton of the Basal Mosasaur Halisaurus platyspondylus from the Severn Formation (Upper Cretaceous: Maastrichtian) of Maryland. Journal of Paleontology. 2000. 74. 2. 309–316. 1306908.