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Alkali Canyon Formation
The Alkali Canyon Formation is a geologic formation in Oregon. It preserves fossils dating back to the Tortonian to Zanclean stages (Hemphillian) of the Neogene period.Alkali Canyon Formation at .orgAlkali Canyon Formation at Fossil content The following fos ...[...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] |
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalonyx
''Megalonyx'' (Greek, "large claw") is an extinct genus of ground sloths of the family Megalonychidae, native to North America during the Pliocene and Pleistocene epochs. It became extinct during the Quaternary extinction event at the end of the Rancholabrean of the Pleistocene, living from ~5 million to 11,000 years ago. The type species, ''M. jeffersonii'', measured about and weighed up to . ''Megalonyx'' is descended from ''Pliometanastes,'' a genus of ground sloth that had arrived in North America during the Late Miocene, prior to the Great American Biotic Interchange. ''Megalonyx'' had the widest distribution of any North American ground sloth, having a range encompassing most of the contiguous United States, extending as far north as Alaska during warm periods. Taxonomy In 1796, Colonel John Stuart sent Thomas Jefferson, shortly before he took office as Vice President of the United States, some fossil bones: a femur fragment, ulna, radius, and foot bones including three ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammut
A mastodon ( 'breast' + 'tooth') is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae). Mastodons inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of the Pleistocene 10,000 to 11,000 years ago. They lived in herds and were predominantly forest-dwelling animals. They generally had a browsing diet, distinct from that of the contemporary Columbian mammoth, which tended towards grazing. ''M. americanum'', the American mastodon, and ''M. pacificus'', the Pacific mastodon, are the youngest and best-known species of the genus. Mastodons disappeared from North America as part of a mass extinction of most of the Pleistocene megafauna, widely believed to have been caused by a combination of climate changes at the end of the Pleistocene and overexploitation by Paleo-Indians. History A Dutch tenant farmer found the first recorded remnant of ''Mammut'', a tooth some in weight, in the village of Cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dipoides
''Dipoides'' is an extinct genus of beaver-grouped rodents. ''Dipoides'' were about two thirds the size of modern Canadian beavers. Where modern beavers have square chisel shaped teeth, ''Dipoides'' teeth were rounded. However an excavation of a site that was once a marsh, in Ellesmere Island, showed signs that they dined on bark and young trees, like modern beavers. The excavation seemed to show that, like modern beavers, ''Dipoides'' dammed streams. Other research suggests that the building of dams by ''Dipoides'' started as a side effect to the consumption of wood and bark, and was a specialization that evolved for cold weather survival due to the earth's cooling during the late Neogene period. Natalia Rybczynski Natalia Rybczynski is a Canadian paleobiologist, professor and researcher. She is a research scientist with the Canadian Museum of Nature and holds a professorship at Carleton University in Ottawa, Ontario. Her doctorate was obtained at Duke Uni ..., of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beaver
Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-largest living rodents after the capybaras. They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet and flat, scaly tails. The two species differ in the shape of the skull and tail and fur color. Beavers can be found in a number of freshwater habitats, such as rivers, streams, lakes and ponds. They are herbivorous, consuming tree bark, aquatic plants, grasses and sedges. Beavers build dams and lodges using tree branches, vegetation, rocks and mud; they chew down trees for building material. Dams impound water and lodges serve as shelters. Their infrastructure creates wetlands used by many other species, and because of their effect on other organisms in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermophilus
''Spermophilus'' is a genus of ground squirrels in the Sciuridae, squirrel family. As traditionally defined the genus was very species-rich, ranging through Europe, Asia and North America, but this arrangement was found to be paraphyletic to the certainly distinct prairie dogs, marmots, and antelope squirrels. As a consequence, all the former ''Spermophilus'' species of North America have been moved to other genera, leaving the European and Asian species as true ''Spermophilus'' (the only exceptions are two Asian ''Urocitellus''). Some species are sometimes called susliks (or sousliks). This name comes from Russian :ru:Суслики, суслик, ''suslik''. In some languages, a derivative of the name is in common usage, for example ''suseł'' in Polish. The scientific name of this genus means "seed-lovers" (gr. σπέρμα ''sperma'', genitive σπέρματος ''spermatos'' – seed; φίλος ''philos'' – friend, lover). Habitat and behavior As typical ground squirr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scapanus
''Scapanus'' is a genus of moles in the family Talpidae. They live in North America from west of the Rockies south to Baja California del Norte, and north to British Columbia, wherever conditions permit a mole population; that is to say, apart from the most sandy, rocky, or developed places. As they are one genus, they are very closely related, but as species, they rarely if ever interbreed successfully. It contains the following living species: * Mexican mole (''S. anthonyi'') * Northern broad-footed mole (''S. latimanus'') * Southern broad-footed mole (''S. occultus'') * Coast mole (''S. orarius'') * Townsend's mole (''S. townsendii'') In addition, there are several extinct species known from fossils. *''Scapanus hagermanensis'' ( Mid Blancan stage, Idaho) *''Scapanus malatinus'' ( Blancan- Quaternary, California). *''Scapanus proceridens'' (Miocene, Oregon and Idaho) *''Scapanus shultzi'' (Miocene, California and Oregon) Distribution Townsend's mole is primarily a Cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiogulo
''Plesiogulo'' is a genus of prehistoric carnivore that lived from Miocene to Pliocene of Africa, Eurasia and North America. An ancestral relationship to the wolverine (''Gulo gulo'') was once suggested, but it is no longer considered likely. However, some authorities still consider it a member of the Guloninae Guloninae is a subfamily of the mammal family Mustelidae distributed across Eurasia and the Americas. It includes martens and the fisher, tayra and wolverine. These genera were formerly included within a paraphyletic definition of the mustelid su .... Species The following species have been currently described for this genus: * †'' P. brachygnathus'' (Schlosser, 1903) * †'' P. botori'' Haile-Selassie, Hlusko & Howell, 2004 * †'' P. crassa'' Teilhard de Chardin, 1945 * †'' P. marshalli'' (Martin, 1928) * † ''P.'' ''lindsayi'' Harrison, 1981 * †'' P. monspessulanus'' Viret, 1939 * †'' P. praecocidens'' Kurtén, 1970 References External linksWhat Exactly I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perognathus
''Perognathus'' is a genus of pocket mouse. Like other members of their family they are more closely related to pocket gophers than to true mice. Characteristics The silky pocket mice are small animals with soft pelage, long tails, and small feet compared to other heteromyids. They have long claws which are used for digging burrows and sifting sandy substrates for seeds. They have also been found to steal seeds from kangaroo rats' dens. They store these seeds in large hairy external cheek pouches. They are nocturnal and are found in arid habitats. They are not true hibernators, but will go into torpor and stay in their burrows for extended periods of time. Species *'' Perognathus alticola'' — White-eared pocket mouse *'' Perognathus amplus'' — Arizona pocket mouse *'' Perognathus fasciatus'' — Olive-backed pocket mouse *''Perognathus flavescens'' — Plains pocket mouse *'' Perognathus flavus'' — Silky pocket mouse *'' Perognathus inornatus'' — San Joaquin pocke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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