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Baltoceras
''Baltoceras'' is a member of the ''Ellesmerocerida'', included in the family, ''Baltoceratidae''. The shell of ''Baltoceras'' is slender with a subcircular cross section, straight transverse sutures, and a large siphuncle in contact with the venter. Septal necks are short but not vestigial; connecting rings are thick; endosiphonal organic deposits are unknown. ''Baltoceras'' ranges in age from Whiterock to Chazy (Middle Ordovician). The few species known are from the upper Pogonip Limestone of Nevada, the Day Point Limestone of New York, and the “Orthoceras limestone” of the Baltic region of Europe. ''Baltoceras'' differs from ''Rioceras'' in the same family in that ''Baltoceras'' has deeper camerae, longer septal necks and thinner connecting rings. Also ''Rioceras'' is earlier, mostly late Canadian in age. It should not be confused with the orthocerid, ''Balticoceras''. References * Flower, R.H. 1964, The Nautiloid Order Ellesmeroceratida (Cephalopoda) Memoir 12; Ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), 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 Celtic Britons, 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 (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, 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 Union of Geological Sciences, Intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nevada
Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the List of U.S. states and territories by area, 7th-most extensive, the List of U.S. states and territories by population, 32nd-most populous, and the List of U.S. states and territories by population density, 9th-least densely populated of the U.S. states. Nearly three-quarters of Nevada's people live in Clark County, Nevada, Clark County, which contains the Las Vegas–Paradise, NV MSA, Las Vegas–Paradise metropolitan area, including three of the state's four largest incorporated cities. Nevada's capital is Carson City, Nevada, Carson City. Las Vegas is the largest city in the state. Nevada is officially known as the "Silver State" because of the importance of silver to its history and economy. It is also known as the "Battle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician Cephalopods Of Europe
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] |
Ordovician Cephalopods
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 Cambr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treatise On Invertebrate Paleontology
The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and extant (still living) invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, taxa with no fossil record whatsoever have just a very brief listing. Publication of the decades-long ''Treatise on Invertebrate Paleontology'' is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post-Paleozoic era caenogastropods (a molluscan group including the whelk and Common periwinkle, periwinkle). Furthermore, every so often, previously published volumes of the ''Treatise'' are revised. Evolution of the proje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthocerida
Orthocerida is an order of extinct Orthoceratoid cephalopods also known as the Michelinocerida that lived from the Early Ordovician () possibly to the Late Triassic (). A fossil found in the Caucasus suggests they may even have survived until the Early Cretaceous (). They were most common however from the Ordovician to the Devonian. Shell form The shell is usually long, and may be straight ("orthoconic") or gently curved. In life, these animals may have been similar to the modern squid, except for the long shell. The internal structure of the shell consists of concavo-convex chambers linked by a centrally-placed tube called a siphuncle. There is a tendency for the chambers to develop cameral deposits, which were used as ballast to balance the long gas-filled shell. Depending on the family, the siphuncle has orthochoanitic (short and straight) or cyrtochoanitic (outwardly curved) septal necks, which protrude from the septa. The shell surface may be (depending on the specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Epoch
The Canadian is the Lower or Early Ordovician in North America. The term is common in the older literature and has been well understood for more than a century. However it has no official recognition by the International Commission on Stratigraphy (ICS) and has been superseded by the more recently defined Ibexian series of western Utah. Background Dana introduced the Canadian as the name for a system separated from the rest of the Ordovician (Weller 1980), then known as the Lower Silurian, and referred to the rest of the Lower Silurian as the Trenton System. At that time the Ordovician had not yet been recognized. Later Ulrich redefined the Canadian as roughly equivalent to the Beekmantown strata of the Lower Ordovician. Flower (1957 p. 17) felt that recognition of the Canadian as a separate system would greatly solve problems in Early Paleozoic stratigraphy. As such, faunas in limestones of Canadian age are uniformly widespread and set off sharply from black shale graptolite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rioceras
''Rioceras'' is an extinct genus of orthocerid cephalopods of the family Baltoceratidae that lived in what would be North America during the Early Ordovician from 480—472 mya, existing for approximately 8 million years.R. H. Flower. 1964. The Nautiloid Order Ellesmeroceratida (Cephalopoda). State Bureau of Mines and Mineral Resources, New Mexico Institute of Mining and Technology, Memoir 12:234 Taxonomy ''Rioceras'' was named by Flower (1964). Its type is ''Rioceras nondescriptum''. It was assigned to ''Baltoceratidae'' by Flower (1964) and Hook and Flower (1977),S. C. Hook and R. H. Flower. 1977. Late Canadian (Zones J, K) cephalopod faunas from Southwestern United States. New Mexico Bureau of Mines and Mineral Resources 32:1-56 but reassigned to the Ellesmeroceratidae by Kröger et al. (2007)B. Kröger, M. S. Beresi, and E. Landing. 2007. Early orthoceratoid cephalopods from the Argentine Precordillera (Lower-Middle Ordovician). Journal of Paleontology 81(6):1266-1283 Whethe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltic Region
The terms Baltic Sea Region, Baltic Rim countries (or simply the Baltic Rim), and the Baltic Sea countries/states refer to slightly different combinations of countries in the general area surrounding the Baltic Sea, mainly in Northern Europe. The term " Baltic states" refers specifically to one such grouping. Etymology The first to name it the ''Baltic Sea'' ( la, Mare Balticum) was 11th century German chronicler Adam of Bremen. Denotation Depending on the context the ''Baltic Sea Region'' might stand for: * The countries that have shorelines along the Baltic Sea: Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, and Sweden. * The group of countries that are members of the inter-governmental ''Baltic Assembly'' and ''Baltic Council of Ministers'', and generally referred to by the shorthand, Baltic states: Estonia, Latvia, and Lithuania. * Estonia, Latvia, Lithuania and Kaliningrad Oblast of Russia, exclaved from the remainder of Russia.«The Balt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pogonip Limestone
Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influenced by nearby bodies of water, topography, and wind conditions. In turn, fog affects many human activities, such as shipping, travel, and warfare. Fog appears when water vapor (water in its gaseous form) condenses. During condensation, molecules of water vapor combine to make tiny liquid water droplets that hang in the air. Sea fog, which shows up near bodies of saline water, is formed as water vapor condenses on bits of salt. Fog is similar to, but less transparent than, mist. Definition The term ''fog'' is typically distinguished from the more generic term ''cloud'' in that fog is low-lying, and the moisture in the fog is often generated locally (such as from a nearby body of water, like a lake or the ocean, or from nearby moist g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motility, able to move, can Sexual reproduction, reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of Cell (biology), cells, the blastula, during Embryogenesis, embryonic development. Over 1.5 million Extant taxon, living animal species have been Species description, described—of which around 1 million are Insecta, insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have Ecology, complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a Symmetry in biology#Bilate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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