Patuxent Formation | |
---|---|
Stratigraphic range: | |
Type | Sedimentary |
Unit of | Potomac Group |
Underlies | Arundel Formation |
Overlies | Basement |
Thickness | up to 250 feet (80 m) |
Lithology | |
Primary | Sand, Gravel |
Other | Clay |
Location | |
Region | Atlantic coastal plain |
Country | U.S.A. |
Extent | Maryland, Washington D. C., Delaware, Virginia |
Type section | |
Named for | Patuxent River |
Named by | W. B. Clark, 1897 [1] |
The Patuxent Formation is a Cretaceous geologic formation of the Atlantic coastal plain.
The Patuxent formation was first described by William Bullock Clark in 1897. [1] The formation is primarily unconsolidated white-grey or orange-brown sand and gravel, with minor clay and silt. The sand often contains kaolinized feldspar, making it an arkose. Clay lumps are common, and sand beds gradually transition to clay. Sandy beds may be crossbedded, which is evidence of shallow water origin.
The Patuxent is the basal unit of the Coastal Plain sedimentary formations and unconformably overlies the crystalline basement rocks. This underlying unconformity is the subsurface equivalent of the Atlantic Seaboard Fall Line.
Propanoplosaurus , a nodosaurid known from a single natural cast and mold of a hatchling, was found recovered from rocks belonging to the Patuxent Formation in Maryland. [2]
Fossil stegosaur tracks have been reported from the formation. [3]
E. Dorf (1952) [4] compared the flora identified in the Patuxent to that of the Wealden Flora in England studied by Albert Seward. [5]
Pollen spores have been identified in the formation by G. J. Brenner (1963). [6] [7]
The type locality is the upper and lower valleys of the Little Patuxent River and Big Patuxent River in Maryland.
Biostratigraphic dating by Dorf (1952) confirmed Early Cretaceous (Neocomian) age. [4]
Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock unit underlying areas of South East England, between the North and South Downs, in an area called the Weald Basin. It is the uppermost unit of the Wealden Group of rocks within the Weald Basin, and the upper portion of the unit is equivalent in age to the exposed portion of the Wessex Formation on the Isle of Wight. It predominantly consists of thinly bedded mudstone. The un-weathered form is blue/grey, and the yellow/orange is the weathered form, it is used in brickmaking.
The Lance (Creek) Formation is a division of Late Cretaceous rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the latest Mesozoic vertebrate faunas. The Lance Formation is Late Maastrichtian in age, and shares much fauna with the Hell Creek Formation of Montana and North Dakota, the Frenchman Formation of southwest Saskatchewan, and the lower part of the Scollard Formation of Alberta.
Yaverlandia is a genus of maniraptoran dinosaur. Known from a partial fossil skull found in Lower Cretaceous strata of the Wessex Formation on the Isle of Wight. it was described as the earliest known member of the pachycephalosaurid family, but research by Darren Naish shows it to have actually been a theropod, seemingly a maniraptoran. The type species is Y. bitholus.
Valdoraptor is a genus of theropod dinosaur from the Early Cretaceous. Its fossils were found in England. It is known only from bones of the feet. The holotype, BMNH R2559, was found near Cuckfield in layers of the Tunbridge Wells Sand Formation dating from the late Valanginian. The specimen is damaged lacking parts of the upper and lower ends. It has a conserved length of 215 millimetres (8.5 in) and an estimated length of 240 millimetres (9.4 in). This genus is paleontologically significant for being the first ornithomimosaur specimen known from England and represents the earliest record of ornithomimosaurs.
Astrodon is a genus of large herbivorous sauropod dinosaur, measuring 20 m (66 ft) in length, 9 m (30 ft) in height and 20 metric tons in body mass. It lived in what is now the eastern United States during the Early Cretaceous period, and fossils have been found in the Arundel Formation, which has been dated through palynomorphs to the Albian about 112 to 110 million years ago.
Monkonosaurus is a dubious genus of herbivorous stegosaurian dinosaur from the Late Jurassic/Early Cretaceous-aged Loe-ein Formation of Tibet. Some sources place it as alive during the Oxfordian - Albian stages, around 163 - 100 million years ago, although Monkonosaurus was probably only alive during the Late Jurassic, making it among the earliest known stegosaurs along with Chungkingosaurus and Bashanosaurus.
The Wealden Group, occasionally also referred to as the Wealden Supergroup, is a group in the lithostratigraphy of southern England. The Wealden group consists of paralic to continental (freshwater) facies sedimentary rocks of Berriasian to Aptian age and thus forms part of the English Lower Cretaceous. It is composed of alternating sands and clays. The sandy units were deposited in a flood plain of braided rivers, the clays mostly in a lagoonal coastal plain.
The Laramie Formation is a geologic formation of the Late Cretaceous (Maastrichtian) age, named by Clarence King in 1876 for exposures in northeastern Colorado, in the United States. It was deposited on a coastal plain and in coastal swamps that flanked the Western Interior Seaway. It contains coal, clay and uranium deposits, as well as plant and animal fossils, including dinosaur remains. The formation contains some of the oldest records of Grass in western North America.
The Dakota is a sedimentary geologic unit name of formation and group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and shales deposited in the Mid-Cretaceous opening of the Western Interior Seaway. The usage of the name Dakota for this particular Albian-Cenomanian strata is exceptionally widespread; from British Columbia and Alberta to Montana and Wisconsin to Colorado and Kansas to Utah and Arizona. It is famous for producing massive colorful rock formations in the Rocky Mountains and the Great Plains of the United States, and for preserving both dinosaur footprints and early deciduous tree leaves.
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.
The Wessex Formation is a fossil-rich English geological formation that dates from the Berriasian to Barremian stages of the Early Cretaceous. It forms part of the Wealden Group and underlies the younger Vectis Formation and overlies the Durlston Formation. The dominant lithology of this unit is mudstone with some interbedded sandstones. It is part of the strata of the Wessex Basin, exposed in both the Isle of Purbeck and the Isle of Wight. While the Purbeck sections are largely barren of vertebrate remains, the Isle of Wight sections are well known for producing the richest and most diverse fauna in Early Cretaceous Europe.
The Vectis Formation is a geological formation on the Isle of Wight and Swanage, England whose strata were formed in the Barremian, approximately 125 million years ago. The environment of deposition was that of a freshwater coastal lagoon with occasional marine influence after the early Aptian marine transgression, transitioning from the floodplain environment of the underlying Wessex Formation. The primary lithology is of laminated grey mudstones. The Vectis Formation is composed of three geological members: the Shepherds Chine member, the Barnes High Sandstone member, and the Cowleaze Chine member. It is overlain by the fully marine Atherfield Clay Formation, part of the Lower Greensand Group. Dinosaur remains are among the fossils that have been recovered from the formation.
The Prince Creek Formation is a geological formation in Alaska with strata dating to the Early Maastrichtian stage of the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.
The Raritan Formation is a Cretaceous (Turonian) sedimentary geologic formation of the Atlantic Coastal Plain.
The Mowry Shale is an Early Cretaceous geologic formation. The formation was named for Mowrie Creek, northwest of Buffalo in Johnson County, Wyoming.
The Chacarilla Formation is an Oxfordian to Early Cretaceous geologic formation of the Tarapacá Basin in northern Chile, close to the border with Bolivia. The marine and fluvial formation preserves several dinosaur trackways and has been declared a Natural Sanctuary in 2004.
The Hensel Formation or Hensel Sand is a Mesozoic geologic formation in Texas. Fossil ornithopod tracks have been reported from the formation.
Propanoplosaurus is a genus of herbivorous nodosaurid dinosaur from the Early Cretaceous Patuxent Formation of Maryland, USA. Its type specimen is a natural cast and partial natural mold of a hatchling.
The Wadhurst Clay Formation is a geological unit which forms part of the Wealden Group and the middle part of the now unofficial Hastings Beds. These geological units make up the core of the geology of the High Weald in the English counties of West Sussex, East Sussex and Kent.