Potomac Group

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Potomac Group
Stratigraphic range: Cretaceous, Aptian–Turonian
Timber Neck, Maryland.png
View of Timber Neck showing the Arundel, Patapsco and Raritan Formations of the Potomac Group
Type Group
Sub-units Patuxent Formation, Arundel Formation, Patapsco Formation, Raritan Formation, Potomac Formation (?)
Underlies Raritan Formation, Magothy Formation
Overlies Boonton Formation
Location
RegionFlag of Delaware.svg  Delaware, Flag of Maryland.svg  Maryland, Flag of New Jersey.svg  New Jersey, Flag of Virginia.svg  Virginia
CountryFlag of the United States.svg  United States
Exposure of part of the Potomac Group at Elk Neck State Park, Maryland Potomac Group 20240413.jpg
Exposure of part of the Potomac Group at Elk Neck State Park, Maryland

The Potomac Group is a geologic group in Delaware, Maryland, New Jersey, and Virginia. It preserves fossils dating back to the Cretaceous period. An indeterminate tyrannosauroid and Priconodon crassus , a nodosaurid, are known from indeterminate sediments belonging to the Potomac Group. [1] The Potomac Group was initially believed to have been Late Jurassic in age by Othniel Charles Marsh [2] but later studies, such as Clark (1897), have found that the Potomac Group is in fact Early-Late Cretaceous (Aptian-Turonian) in age. [3] The most famous member of the group is the Arundel Formation, which preserves a high diversity of terrestrial vertebrate fauna and provides the most comprehensive look at the dinosaurian fauna of eastern North America during the Early Cretaceous. [4]

See also

Related Research Articles

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Coelurus is a genus of coelurosaurian dinosaur from the Late Jurassic period. The name means "hollow tail", referring to its hollow tail vertebrae. Although its name is linked to one of the main divisions of theropods (Coelurosauria), it has historically been poorly understood, and sometimes confused with its better-known contemporary Ornitholestes. Like many dinosaurs studied in the early years of paleontology, it has had a confusing taxonomic history, with several species being named and later transferred to other genera or abandoned. Only one species is currently recognized as valid: the type species, C. fragilis, described by Othniel Charles Marsh in 1879. It is known from one partial skeleton found in the Morrison Formation of Wyoming, United States. It was a small bipedal carnivore with elongate legs.

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<span class="mw-page-title-main">Tyrannosauroidea</span> Extinct superfamily of dinosaurs

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<i>Dryptosaurus</i> Extinct genus of dinosaurs

Dryptosaurus is a genus of eutyrannosaurian theropod dinosaur that lived on the island continent of Appalachia approximately 67.6 million years ago during the end of the Maastrichtian age of the Late Cretaceous period. Dryptosaurus was a large, bipedal, ground-dwelling carnivore that could grow up to 7.5 metres (25 ft) long and weigh up to 756–1,500 kilograms (1,667–3,307 lb). Although it is now largely unknown outside of academic circles, the famous 1897 painting of the genus by Charles R. Knight made Dryptosaurus one of the more widely known dinosaurs of its time, in spite of its poor fossil record. First described by Edward Drinker Cope in 1866 and later renamed by Othniel Charles Marsh in 1877, Dryptosaurus is among the first theropod dinosaurs ever known to science.

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<span class="mw-page-title-main">Arundel Formation</span> Geological formation in Maryland

The Arundel Formation, also known as the Arundel Clay, is a clay-rich sedimentary rock formation, within the Potomac Group, found in Maryland of the United States of America. It dates to the Early Cretaceous, and is of late Aptian or early Albian age. This rock unit had been economically important as a source of iron ore, but is now more notable for its dinosaur fossils. It is named for Anne Arundel County, Maryland.

<span class="mw-page-title-main">Wayan Formation</span> Stratigraphic Unit in Idaho

The Wayan Formation is a geological formation in Idaho whose strata date back to the latest Early Cretaceous and the earliest Late Cretaceous. Dinosaur, other reptile, mammal, and micro and macro-floral remains are among the fossils that have been recovered from the formation. The lack of extensive outcrops, limited geographic extent, and extreme structural deformation have limited paleontological explorations of the Wayan.

The Merchantville Formation is a geological formation in the northeastern United States whose strata date back to the Late Cretaceous, around the time of the Santonian and Campanian age. Dinosaur remains are among the fossils that have been recovered from the formation.

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Xiongguanlong is an extinct genus of tyrannosauroid theropod from the Early Cretaceous period of what is now China. The type and only species is X. baimoensis. The generic name comes from Jiayuguan City and the Mandarin word "long" which means dragon. The specific epithet, "baimoensis" is a latinization of the Mandarin word for "white ghost" in reference to one of the geological features of the type locality.

<span class="mw-page-title-main">Raritan Formation</span> Mesozoic geologic formation containing dinosaur fossils and amber

The Raritan Formation is a Cretaceous (Turonian) sedimentary geologic formation of the Atlantic Coastal Plain.

<span class="mw-page-title-main">Patuxent Formation</span> Cretaceous geologic formation of the Atlantic coastal plain

The Patuxent Formation is a Cretaceous geologic formation of the Atlantic coastal plain.

<span class="mw-page-title-main">Appalachia (landmass)</span> Mesozoic land mass separated from Laramidia to the west by the Western Interior Seaway

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<span class="mw-page-title-main">Paleontology in Maryland</span> Paleontological research in the U.S. state of Maryland

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The Tar Heel Formation, also known as the Coachman Formation in South Carolina, is a Late Cretaceous geologic formation in North Carolina and South Carolina, USA. It preserves fossils, including amber dating back to the Cretaceous period. A locality known as Phoebus Landing, has been dated to 78.5-77.1 Ma, and the formation has been overall dated to the early Campanian based on fossil pollen.

<span class="mw-page-title-main">Patapsco Formation</span> Fossil-rich geologic formation on the East Coast of the United States

The Patapsco Formation is a geologic formation of varigated clays, sandy clays, and sand in Virginia, the District of Columbia, Maryland, Delaware, Pennsylvania, and in the subsurface of New Jersey. It preserves fossils such as plants and molluscs dating back to the Cretaceous period.

The Holly Creek Formation is a geologic formation in Arkansas. It preserves fossils dating back to the Cretaceous period which belong to the Trinity Group.

References

  1. Brownstein, Chase Doran (2018). "A Tyrannosauroid from the Lower Cenomanian of New Jersey and Its Evolutionary and Biogeographic Implications". Bulletin of the Peabody Museum of Natural History. 59 (1): 95–105. doi:10.3374/014.058.0210. ISSN   0079-032X.
  2. Marsh, Othniel Charles (1888). "Notice of a New Genus of Sauropoda and Other New Dinosaurs From the Potomac Formation". American Journal of Science. s3-35 (205): 89–94. doi:10.2475/ajs.se-305.205.89.
  3. Clark, W.B. (1897). Outline of present knowledge of the physical features of Maryland (Report). Volume Series. Vol. 1. Maryland Geological Survey. pp. 172–188.
  4. Frederickson, Joseph A.; Lipka, Thomas R.; Cifelli, Richrad L. (2018-08-28). "Faunal composition and paleoenvironment of the Arundel Clay (Potomac Formation; Early Cretaceous), Maryland, USA". Palaeontologia Electronica 21.2.31A. doi:10.26879/847 . Retrieved 2024-10-28.