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Logan Formation
The Logan Formation is the name given to a Lower Carboniferous (early Osagean) siltstone, sandstone and conglomeratic unit exposed in east-central Ohio and parts of western West Virginia, USA. Stratigraphy and paleoenvironment The Logan Formation was named by Andrews (1870) and originally described as a "buff-colored, fine-grained sandstone" above the Waverly Formation and below the Maxville Limestone. Bork and Malcuit (1979) concluded that the Logan Formation was deposited on a shallow marine shelf in a generally transgressing sea. The age of the Logan Formation has been established as early Osagean (Tn3) by the occurrences of brachiopods, ammonoids, conodonts and miospores (Clayton et al., 1998; Matchen and Kammer, 2006). References * * * * Image:LoganConglomerateWooster.jpg, Conglomerate in the Logan Formation exposed in Wooster, Ohio, USA. Image:LoganBrachiopodsWooster.jpg, Brachiopod internal and external molds in the Logan Formation in Wooster, Ohio. Image:Aviculopec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wooster, Ohio
Wooster ( ) is a city in Wayne County, Ohio, United States, and its county seat. Located in northeastern Ohio, the city lies approximately south-southwest of Cleveland, southwest of Akron and west of Canton. The population was 27,232 at the 2020 census. It is the largest in Wayne County, and the center of the Wooster micropolitan area. Wooster has the main branch and administrative offices of the Wayne County Public Library, and is home to the private College of Wooster. '' fDi magazine'' ranked Wooster among North America's top 10 micro cities for business friendliness and strategy in 2013. History Wooster was established in 1808 by John Bever, William Henry, and Joseph Larwill and named after David Wooster, a general in the American Revolutionary War. Geography According to the United States Census Bureau, the city has a total area of , of which is land and is water. It lies along Killbuck Creek, a tributary of the Walhonding River. The local bedrock consists of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonoid
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family Nautilidae). The earliest ammonoids appeared during the Emsian stage of the Early Devonian (410.62 million years ago), with the last species vanishing during or soon after the Cretaceous–Paleogene extinction event (66 million years ago). They are often called ammonites, which is most frequently used for members of the order Ammonitida, the only remaining group of ammonoids from the Jurassic up until their extinction. Ammonoids exhibited considerable diversity over their evolutionary history, with over 10,000 species having been described. Ammonoids are excellent index fossils, and they have been frequently used to link rock layers in which a particular species or genus is found to specific geologic time periods. Their fossil shells usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siltstone Formations Of The United States
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeability and porosity is relatively low, siltstone is sometimes a tight gas reservoir rock, an unconventional reservoir for natural gas that requires hydraulic fracturing for economic gas production. Siltstone was prized in ancient Egypt for manufacturing statuary and cosmetic palettes. The siltstone quarried at Wadi Hammamat was a hard, fine-grained siltstone that resisted flaking and was almost ideal for such uses. Description There is not complete agreement on the definition of siltstone. One definition is that siltstone is mudrock (clastic sedimentary rock containing at least 50% clay and silt) in which at least 2/3 of the clay and silt fraction is composed of silt-sized particles. Silt is defined as grains 2–62 μm in diameter, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone Formations Of The United States
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains, cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar, because they are the most resistant minerals to the weathering processes at the Earth's surface. Like uncemented sand, sandstone may be imparted any color by impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Because sandstone beds can form highly visible cliffs and other topographic features, certain colors of sandstone have become strongly identified with certain regions, such as the red rock deserts of Arches National Park and other areas of the American Southwest. Rock formations composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboniferous Southern Paleotropical Deposits
The Carboniferous ( ) is a geologic period and system of the Paleozoic era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the Permian Period, Ma. It is the fifth and penultimate period of the Paleozoic era and the fifth period of the Phanerozoic eon. In North America, the Carboniferous is often treated as two separate geological periods, the earlier Mississippian and the later Pennsylvanian. The name ''Carboniferous'' means "coal-bearing", from the Latin ("coal") and ("bear, carry"), and refers to the many coal beds formed globally during that time. The first of the modern "system" names, it was coined by geologists William Conybeare and William Phillips in 1822, based on a study of the British rock succession. Carboniferous is the period during which both terrestrial animal and land plant life was well established. Stegocephalia (four-limbed vertebrates including true tetrapods), whose forerunners (tetrapodomor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mississippian United States
Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago * Mississippian cultures, a network of precontact cultures across the midwest and Eastern Woodlands in North America that flourished from about 800 to 1540 CE * Mississippian Railway, a short-line railroad * relating to the state of Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ... See also * Mississippi (other) {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platyceratidae
Platyceratidae is an extinct family of Paleozoic sea snails, marine gastropod mollusks. This family may belong in the Patellogastropoda or the Neritimorpha. Platyceratids are known for the complex symbiotic relationships they had with crinoids. Platyceratids are thought to have been parasitic on crinoids, either drilling into the stomach to steal the crinoid's food in a form of kleptoparasitism or drilling into the anal sac to feed on the gonads or the hindgut. Previous authors have suggested that platyceratids were commensalists which fed on crinoid fecal matter without harming the crinoid, but more recent studies have shown that platyceratids did have a negative effect on their crinoid hosts as would be expected if they were actively parasitic. It has been suggested that the large spines present on many species of crinoids served to deter predators who might damage or harm the crinoid in an effort to feed on the platyceratid snails infesting it. This is the only family in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crinoid
Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are members of the largest crinoid order, Comatulida. Crinoids are echinoderms in the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. They live in both shallow water and in depths of over . Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather planktonic particles from the water. At some stage in their lives, most crinoids have a sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trace Fossil
A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or by mineralization. The study of such trace fossils is ichnology - the work of ichnologists. Trace fossils may consist of physical impressions made on or in the substrate by an organism. For example, burrows, borings ( bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints, feeding marks, and root cavities may all be trace fossils. The term in its broadest sense also includes the remains of other organic material produced by an organism; for example coprolites (fossilized droppings) or chemical markers (sedimentological structures produced by biological means; for example, the formation of stromatolites). However, most sedimentary struct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
