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Blakely Sandstone
The Blakely Sandstone is a Middle Ordovician geologic formation in the Ouachita Mountains of Arkansas and Oklahoma. First described in 1892, this unit was not named until 1909 by Albert Homer Purdue in his study of the Ouachita Mountains of Arkansas. Purdue had initially named this unit the Caddo Shale at a 1907 Geological Society of America meeting, but later redefined and renamed the unit as the Ouachita Shale. He again renamed the unit to the Blakely Sandstone in a letter to Edward Oscar Ulrich, to which Ulrich used in a 1911 publication, becoming the first reference using this name. Ulrich assigned the Blakely Mountain in Garland County, Arkansas as the type locality, but did not designate a stratotype. As of 2017, a reference section for this unit has yet to be designated. Paleofauna Conodonts * ''Cordylodus'' : ''C. horridus'' * '' Hisiodella'' : ''H. holodentata'' * '' Leptochirognathus'' : ''L. quadratus'' * '' Paraprioniodus'' : ''P. costatus'' * ''Periodon'' : ''P. ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician Geology Of Oklahoma
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian Perio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleontology In Arkansas
Paleontology in Arkansas refers to paleontological research occurring within or conducted by people from the United States, U.S. state of Arkansas. The fossil Fossil record, record of Arkansas spans from the Ordovician to the Eocene. Nearly all of the state's fossils have come from ancient invertebrate life. During the early Paleozoic, much of Arkansas was covered by seawater. This sea would come to be home to creatures including ''Archimedes (bryozoan), Archimedes'', brachiopods, and conodonts. This sea would begin its withdrawal during the Carboniferous, and by the Permian the entire state was dry land. Landform, Terrestrial conditions continued into the Triassic, but during the Jurassic, another sea encroached into the state's southern half. During the Cretaceous the state was still covered by seawater and home to marine invertebrates such as ''Belemnitella''. On land the state was home to long necked sauropod dinosaurs, who left behind footprints and ostrich dinosaurs such as ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fossiliferous Stratigraphic Units In Arkansas
This article contains a list of fossil-bearing stratigraphic units in the state of Arkansas, U.S. Sites See also * Paleontology in Arkansas References * {{DEFAULTSORT:Fossiliferous stratigraphic units in Arkansas Arkansas Stratigraphic units A stratigraphic unit is a volume of Rock (geology), rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrology, petrographic, lithology, lithologic or paleontology, p ... Stratigraphy of Arkansas Arkansas geography-related lists United States geology-related lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetragraptus
''Tetragraptus'' is an extinct genus of graptolites from the Ordovician period. Species * ''T. akzharensis'' * '' T. approximatus'' * '' T. fruticosus'' * ''T. insuetus'' Distribution Fossils of ''Tetragraptus'' have been found in Argentina, Australia, Bolivia, Canada (Quebec, Yukon, Newfoundland and Labrador and Northwest Territories), Chile, China, Colombia (near Caño Cristales, Meta), the Czech Republic, France, Morocco, New Zealand, Norway, the Russian Federation, Spain, Sweden, the United Kingdom, and the United States (Alaska, Idaho, Nevada, Utah).''Tetragraptus'' at Fossilworks
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Phyllograptus
''Phyllograptus'' is a graptolite genus of the order Graptoloidea, in the family Phyllograptidae. Fossils of this genus have been found in the Early Ordovician (475-473 million years ago), in the sediments of Australia, Bolivia, Canada, Chile, China, New Zealand, Norway, Spain, Sweden, the United Kingdom and United States. The normal length of a colony of these leaf-shaped animals could reach a length of . They were passively mobile planktonic suspension feeders. ''Phyllograptus'' species are excellent index fossils or guide fossils for identifying Ordovician rocks. Species * ''Phyllograptus angustifolius'' * ''Phyllograptus anna'' * ''Phyllograptus densus'' * ''Phyllograptus glossograptoides'' * ''Phyllograptus rotundatus'' References * Cyril Walker & David Ward (1993) - Fossielen: Sesam Natuur Handboeken, Bosch & Keuning, Baarn. Graptolite genera Graptoloidea Index fossils Early Ordovician animals Paleozoic life of the Northwest Territories {{ordovician ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Didymograptus
''Didymograptus'' is an extinct genus of graptolites with four rows of cups. They lived during the Middle Ordovician, to Late Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ....''Didymograptus'' at Fossilworks.org Distribution Fossils of ''Didymograptus'' have been found in Argentina, Australia, Bolivia, Canada (Northwest Territories, Quebec, Yukon, Newfoundland and Labrador), Chile, China, Colombia ([...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichograptus
''Dichograptus'' (meaning ''two-branched writing'' or ''double-line marks'') is an extinct genus of graptolites from the Ordovician. ''Dichograptus'' probably fed on plankton. Individual animals were very tiny, only growing a few millimeters in length (1/8 of an inch). Distribution Fossils of ''Dichograptus'' have been found in Argentina, Chile, China, Colombia (near Caño Cristales, Meta), New Zealand, Norway, and the United Kingdom.''Dichograptus'' at Fossilworks
Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database
The Paleobiology Database is an online resource for information on the di ...
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Spinodus
''Spinodus'' is a genus of conodont Conodonts (Greek ''kōnos'', "cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which ...s. A new species, ''S. wardi'', was described from the middle Ordovician of Canada by Svend Stouge in 2012. Species * ''Spinodus spinatus'' (Hadding, 1913) * ''Spinodus wardi'' Stouge, 2012 References {{Taxonbar, from=Q7577639 Conodont genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
