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Arundel Clay
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 is of Aptian age (Lower Cretaceous). This rock unit had been economically important as a source of iron ore, but is now more notable for its dinosaur fossils. It consists of clay lenses within depressions in the upper part of the Patuxent Formation that may represent oxbow swamp facies. It is named for Anne Arundel County, Maryland. Vertebrate paleofauna Dinosaurs Dinosaurs present include cf. ''Acrocanthosaurus'', the possible ornithischian ''Magulodon'', the poorly known theropods ''"Allosaurus" medius'', '' "Creosaurus" potens'', and ''"Coelurus" gracilis'', the ornithomimosaurian ''"Dryosaurus" grandis'', as well as another indeterminate ornithomimosaurian (though it most likely is ''Nedcolbertia''), the sauropod ''Astrodon'', the nodosaurid ''Priconodon'', a possible basal ceratopsian, and potential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur Park (Prince George's County, Maryland)
Dinosaur Park is a park located in the 13200 block of Mid-Atlantic Boulevard, near Laurel and Muirkirk, Maryland, and operated by the Prince George's County Department of Parks and Recreation. The park features a fenced area where visitors can join paleontologists and volunteers in searching for early Cretaceous fossils. The park also has an interpretive garden with plants and information signs. The park is in the approximate location of discoveries of ''Astrodon'' teeth and bones as early as the 19th century. In the 18th and 19th centuries, the clays of the Muirkirk Deposit in Prince George's County, Maryland were mined for siderite, or iron ore. Iron furnaces located throughout the region melted down siderite to produce iron and steel used in construction and manufacturing. In 1858, African-American miners working in open pit mines were the first to discover dinosaur fossils in Maryland. Among the first scientists to explore the Muirkirk Deposit was Maryland state geologist Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Cretaceous
Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eighteen miles southwest of Gloucester and fifteen miles northeast of Bristol. Lower Wick is within the civil ... Gloucestershire, England See also * Nizhny {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryosaurus
''Dryosaurus'' ( , meaning 'tree lizard', Greek ' () meaning 'tree, oak' and () meaning 'lizard'; the name reflects the forested habitat, not a vague oak-leaf shape of its cheek teeth as is sometimes assumed) is a genus of an ornithopod dinosaur that lived in the Late Jurassic period. It was an iguanodont (formerly classified as a hypsilophodont). Fossils have been found in the western United States and were first discovered in the late 19th century. '' Valdosaurus canaliculatus'' and '' Dysalotosaurus lettowvorbecki'' were both formerly considered to represent species of ''Dryosaurus''. Description Based on known specimens, they had been estimated to have reached up to long and to have weighed up to . However, as no known adult specimens of the genus have been found, the adult size remains unknown. In 2018, the largest specimen (CM 1949) was concluded to be from another species; revising the identity of this specimen put the previous research on size and growth into question. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithomimosauria
Ornithomimosauria ("bird-mimic lizards") are theropod dinosaurs which bore a superficial resemblance to the modern-day ostrich. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous Period (geology), Period of Laurasia (now Asia, Europe and North America), as well as Africa and possibly Australia. The group first appeared in the Early Cretaceous and persisted until the Late Cretaceous. Primitive members of the group include ''Nqwebasaurus'', ''Pelecanimimus'', ''Shenzhousaurus'', ''Hexing'' and ''Deinocheirus'', the arms of which reached 2.4 m (8 feet) in length. More advanced species, members of the family Ornithomimidae, include ''Gallimimus'', ''Struthiomimus'', and ''Ornithomimus''. Some paleontologists, like Paul Sereno, consider the enigmatic Alvarezsauridae, alvarezsaurids to be close relatives of the ornithomimosaurs and place them together in the superfamily Ornithomimoidea (see classification below). Description The skulls of ornithomimosaurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelurus
''Coelurus'' ( ) is a genus of coelurosaurian dinosaur from the Late Jurassic period (mid-late Kimmeridgian faunal stage, 155–152 million years ago). The name means "hollow tail", referring to its hollow tail vertebrae (Greek κοῖλος, ''koilos'' = hollow + οὐρά, ''oura'' = tail). 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. Description ''C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capitalsaurus
This list of informally named dinosaurs is a listing of dinosaurs (excluding Aves; birds and their extinct relatives) that have never been given formally published scientific names. This list only includes names that were not properly published (" unavailable names") and have not since been published under a valid name (see list of dinosaur genera for valid names). The following types of names are present on this list: * '' Nomen nudum'', Latin for "naked name": A name that has appeared in print but has not yet been formally published by the standards of the International Commission on Zoological Nomenclature. ''Nomina nuda'' (the plural form) are invalid, and are therefore not italicized as a proper generic name would be. * '' Nomen manuscriptum'', Latin for "manuscript name": A name that appears in manuscript but was not formally published. A ''nomen manuscriptum'' is equivalent to a ''nomen nudum'' for everything except the method of publication, and description. * '' Nomen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allosaurus
''Allosaurus'' () is a genus of large carnosaurian theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic epoch (Kimmeridgian to late Tithonian). The name "''Allosaurus''" means "different lizard" alluding to its unique (at the time of its discovery) concave vertebrae. It is derived from the Greek (') ("different, other") and (') ("lizard / generic reptile"). The first fossil remains that could definitively be ascribed to this genus were described in 1877 by paleontologist Othniel Charles Marsh. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles. ''Allosaurus'' was a large bipedal predator. Its skull was light, robust and equipped with dozens of sharp, serrated teeth. It averaged in length for ''A. fragilis'', with the largest specimens estimated as being long. Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magulodon
This list of informally named dinosaurs is a listing of dinosaurs (excluding Aves; birds and their extinct relatives) that have never been given formally published scientific names. This list only includes names that were not properly published ("unavailable names") and have not since been published under a valid name (see list of dinosaur genera for valid names). The following types of names are present on this list: * ''Nomen nudum'', Latin for "naked name": A name that has appeared in print but has not yet been formally published by the standards of the International Commission on Zoological Nomenclature. ''Nomina nuda'' (the plural form) are invalid, and are therefore not italicized as a proper generic name would be. * '' Nomen manuscriptum'', Latin for "manuscript name": A name that appears in manuscript but was not formally published. A ''nomen manuscriptum'' is equivalent to a ''nomen nudum'' for everything except the method of publication, and description. * '' Nomen ex d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithischia
Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek stem ' (), meaning "of a bird", and ' (), plural ', meaning "hip joint". However, birds are only distantly related to this group as birds are theropod dinosaurs. Ornithischians with well known anatomical adaptations include the ceratopsians or "horn-faced" dinosaurs (e.g. ''Triceratops''), the pachycephalosaurs or "thick-headed" dinosaurs, the armored dinosaurs (Thyreophora) such as stegosaurs and ankylosaurs, and the ornithopods. There is strong evidence that certain groups of ornithischians lived in herds, often segregated by age group, with juveniles forming their own flocks separate from adults. Some were at least partially covered in filamentous (hair- or feather- like) pelts, and there is much debate over whether these filaments fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrocanthosaurus
''Acrocanthosaurus'' ( ; ) is a genus of carcharodontosaurid dinosaur that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous, from 113 to 110 million years ago. Like most dinosaur genera, ''Acrocanthosaurus'' contains only a single species, ''A. atokensis''. Its fossil remains are found mainly in the U.S. states of Oklahoma, Texas, and Wyoming, although teeth attributed to ''Acrocanthosaurus'' have been found as far east as Maryland, suggesting a continent wide range. ''Acrocanthosaurus'' was a bipedal predator. As the name suggests, it is best known for the high neural spines on many of its vertebrae, which most likely supported a ridge of muscle over the animal's neck, back, and hips. ''Acrocanthosaurus'' was one of the largest theropods, with the largest known specimen reaching in length and weighing approximately . Large theropod footprints discovered in Texas may have been made by ''Acrocanthosaurus'', although there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facies
In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with specified characteristics, which can be any observable attribute of rocks (such as their overall appearance, composition, or condition of formation), and the changes that may occur in those attributes over a geographic area. A facies encompasses all of the characteristics of a rock including its chemical, physical, and biological features that distinguish it from adjacent rock. The term facies was introduced by the Swiss geologist Amanz Gressly in 1838 and was part of his significant contribution to the foundations of modern stratigraphy, which replaced the earlier notions of Neptunism. Types of facies Sedimentary facies Ideally, a Sedimentary structures, sedimentary facies is a distinctive rock unit that forms under certain conditions of sedimentation, reflecting a particular process or environment. Sedimentary facies are either descriptive or interpretative. Sedimentary facies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxbow Lake
An oxbow lake is a U-shaped lake or pool that forms when a wide meander of a river is cut off, creating a free-standing body of water. In South Texas, oxbows left by the Rio Grande are called '' resacas''. In Australia, oxbow lakes are called billabongs. The word "oxbow" can also refer to a U-shaped bend in a river or stream, whether or not it is cut off from the main stream. Geology An oxbow lake forms when a meandering river erodes through the neck of one of its meanders. This takes place because meanders tend to grow and become more curved over time. The river then follows a shorter course that bypasses the meander. The entrances to the abandoned meander eventually silt up, forming an oxbow lake. Because oxbow lakes are stillwater lakes, with no current flowing through them, the entire lake gradually silts up, becoming a bog or swamp and then evaporating completely. When a river reaches a low-lying plain, often in its final course to the sea or a lake, it meanders wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
