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Stromatoporoid
Stromatoporoidea is an extinct clade of sea sponges common in the fossil record from the Ordovician through the Devonian. They were especially abundant and important reef-formers in the Silurian and most of the Devonian.Stock, C.W. 2001, Stromatoporoidea, 1926–2000: ''Journal of Paleontology'', v. 75, p. 1079–1089. The group was previously thought to be related to the corals and placed in the phylum Cnidaria. They are now classified in the phylum Porifera, specifically the sclerosponges. There are numerous fossil forms with spherical, branching or encrusting skeletons of laminated calcite with vertical ''pillars'' between the ''laminae''. Specimen of its oldest genus, ''Priscastroma'', have been found within the Middle Ordovician Sediments. This same genus has been referred to as the species ''P. gemina'' Khrom., and is known to have been known to branch off into two forms, A and B. Form A gave rise to the genus ''Cystostroma'' while form B gave rise to the genus ''Labechi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stromatoporoidea
Stromatoporoidea is an extinct clade of sea sponges common in the fossil record from the Ordovician through the Devonian. They were especially abundant and important reef-formers in the Silurian and most of the Devonian.Stock, C.W. 2001, Stromatoporoidea, 1926–2000: ''Journal of Paleontology'', v. 75, p. 1079–1089. The group was previously thought to be related to the corals and placed in the phylum Cnidaria. They are now classified in the phylum Porifera, specifically the sclerosponges. There are numerous fossil forms with spherical, branching or encrusting skeletons of laminated calcite with vertical ''pillars'' between the ''laminae''. Specimen of its oldest genus, ''Priscastroma'', have been found within the Middle Ordovician Sediments. This same genus has been referred to as the species ''P. gemina'' Khrom., and is known to have been known to branch off into two forms, A and B. Form A gave rise to the genus ''Cystostroma'' while form B gave rise to the genus ''Labechia'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cairn Formation
The Cairn Formation is a geologic formation of Late Devonian (Frasnian) age in the Western Canada Sedimentary Basin. It was named for the Cairn River near its junction with the Southesk River in Jasper National Park by D.J. McLaren in 1955.McLaren, D.J. 1955. Devonian formations in the Alberta Rocky Mountains between the Bow and Athabasca Rivers. Geological Survey of Canada, Bulletin 35. The Cairn Formation is stratigraphically equivalent to the Leduc Formation, which is a major oil-producing formation in central Alberta. Like the Leduc Formation, it was deposited in reef environments and is highly fossiliferous.Shields, M.J. and Geldsetzer, H.H.J. 1992. The MacKenzie margin, Southesk-Cairn carbonate complex: depositional history, stratal geometry and comparison with other Late Devonian platform-margins. Bulletin of Canadian Petroleum Geology, vol. 40, no. 3, p. 274-293.Bloy, G.R., Hunter, I.G. and Leggett, S.R. 1984. Depositional environments of the Devonian Cairn Formation, Rocky ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hangenberg Event
The Hangenberg event, also known as the Hangenberg crisis or end-Devonian extinction, is a mass extinction that occurred at the end of the Famennian stage, the last stage in the Devonian Period (roughly 358.9 ± 0.4 million years ago). It is usually considered the second-largest extinction in the Devonian Period, having occurred approximately 13 million years after the Late Devonian mass extinction (Kellwasser event) at the Frasnian-Famennian boundary. The Hangenberg event was an anoxic event marked by a layer of black shale, and it has been proposed to have been related to a rapid sea-level fall from the last phase of the Devonian Southern Hemisphere glaciation. It has also been suggested to have been linked to an increase in terrestrial plant cover. That would have led to increased nutrient supply in rivers and may have led to eutrophication of semi-restricted epicontinental seas and could have stimulated algal blooms. However, support for a rapid increase in plant cover at the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rugosa
The rugosa, also called the tetracorallia or horn coral, are an extinct order of solitary and colonial corals that were abundant in Middle Ordovician to Late Permian seas. Solitary rugosans (e.g., '' Caninia'', '' Lophophyllidium'', '' Neozaphrentis'', '' Streptelasma'') are often referred to as horn corals because of a unique horn-shaped chamber with a wrinkled, or rugose, wall. Some solitary rugosans reached nearly a meter in length. However, some species of rugose corals could form large colonies (e.g., ''Lithostrotion''). When radiating septa were present, they were usually in multiples of four, hence ''Tetracoralla'' in contrast to modern '' Hexacoralla'', colonial polyps generally with sixfold symmetry. Rugose corals have a skeleton made of calcite that is often fossilized. Like modern corals (Scleractinia), rugose corals were invariably benthic, living on the sea floor or in a reef-framework. Some symbiotic rugose corals were endobionts of Stromatoporoidea, especially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian Animals
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyser Formation
The Late Silurian to Early Devonian Keyser Formation is a mapped limestone bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia. Description The Keyser is a nodular limestone overlain by thick- and thin-bedded limestone and laminated limestone at its type locality in Keyser, West Virginia. In central Pennsylvania, the basal "calico" limestone is a fossiliferous, medium-light- to medium-gray very thick bedded calcilutite containing numerous small irregular patches of clear calcite. The abundantly fossiliferous, nodular limestone at the base overlies the "calico". Overlying this is 5 to 6 m of fragmental calcarenite containing abundant crinoid columnals. Above the calcarenite is 6 m of fossiliferous, banded calcisiltite. The uppermost 15 m is a sequence alternating between laminated, stromatolitic calcisiltite, and calcilutite and calcisiltite that are argillaceous and fossiliferous. Depositional environment The depositional environment of the Keyser is interpret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbus Limestone
The Columbus Limestone is a mapped bedrock unit consisting primarily of fossiliferous limestone, and it occurs in Ohio, Pennsylvania, and Virginia in the United States, and in Ontario, Canada. Description Depositional environment The depositional environment was most likely shallow marine. Stratigraphy The Columbus conformably overlies the Lucas Dolomite in northeastern Ohio, and unconformably overlies other dolomite elsewhere. It unconformably underlies the Ohio Shale in northwestern Ohio and the Delaware Limestone in eastern Ohio. Its members include: Bellepoint, Marblehead, Tioga Ash Bed, Venice, Delhi, Klondike, and East Liberty. Notable Exposures *The type section is located in Columbus, Ohio. *The glacial grooves on Kelleys Island are cut into the Columbus Limestone. It is also quarried there. *An exposure in Ontario is located at Ingersoll, Ontario. Fossils The Columbus Limestone contains brachiopods, trilobites, bryozoans, mollusks, corals, stromatoporoids and echi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Sponges
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornulitida
Cornulitida is an extinct order of encrusting animals from class Tentaculita, which were common around the globe in the Ordovician to Devonian oceans, and survived until the Carboniferous. The organisms had shells, and were subject to predation by boring and other means from the Ordovician onwards. Many survived attacks by predators. Several cornulitids were endobiotic symbionts in the stromatoporoids and tabulates. Their affinity is unknown; they have been placed in many phyla, and have been considered worms, corals, molluscs and more. They appear to be closely related to other taxa of uncertain affinity, including the microconchids, trypanoporids and tentaculitid Tentaculita is an extinct class of uncertain placement ranging from the Early Ordovician to the Middle Jurassic. They were suspension feeders with a near worldwide distribution. For a more thorough discussion, see ''Tentaculites''. The presenc ...s. References {{Taxonbar, from=Q5171922 Tentaculita M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by total area. Its southern and western border with the United States, stretching , is the world's longest binational land border. Canada's capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. Indigenous peoples have continuously inhabited what is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
