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Ohio, US



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State Fossil:
State fossil from Ohio

Growing up to an estimated 71 cm, the trilobite Isotelus is one of the largest trilobites known. This predatory, “three-lobed” arthropod hunted smaller trilobites in the warm, shallow sea covering North America during the Ordovician Period (~ 490-430 million years ago).

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Paleontology and geology

The Precambrian: There are no Precambrian rocks at the surface in Ohio, and thus, little is known about this time.

The Paleozoic: Cambrian rocks, known from drill cores in Ohio, indicate that a shallow sea flooded the state during that time. By the Ordovician, muds from the emerging mountains in the northeast were deposited in this sea, and its waters teemed with brachiopods, bryozoans, corals, and crinoids. The Silurian ocean was largely mud-free across Ohio and large coral-sponge reefs separated the shallower waters across much of the state from the deeper waters of marine basins to the north and east. Corals, brachiopods, and stalked echinoderms are common fossils in Ohio’s Silurian and Early Devonian rocks, but by the end of the Devonian, these oceans became oxygen-poor and supported relatively little ocean-floor life. During the Early Carboniferous, sediments from the eroding Appalachian Mountains to the east formed extensive marine deposits of muds and silts. The Late Carboniferous brought the development of large deltaic systems and only rare occurrences of oceanic conditions. Coal-forming swampy environments were an important part of these vast deltas, and plant fossils are common. Permian rocks indicate that Ohio was fully terrestrial at this time. Lakes, rivers, and other habitats dominated the landscape; fossils of ferns and horsetails are common.

The Mesozoic and Cenozoic: There are no Mesozoic rocks preserved in Ohio, indicating that this was primarily a time of extensive erosion. This situation continued into the early part of the Cenozoic; consequently, there are no Tertiary rocks preserved in the state.

The Cenozoic: The Early Quaternary record in Ohio is one of massive glacial advances and retreats. At the time of the last glaciation, ice was as much as one mile thick in the area of present-day Cleveland. During these glacial times, mammoths, mastodons, ground sloths, giant beavers, and musk oxen roamed the area.

Links to more on Ohio paleontology

Organizations | Education and Exhibits | Resources


Societies and Clubs (showing 3 of 3 listings)

Ohio Geological Society: Formed in 1961, this non-profit organization, affiliated with AAPG and its Eastern Section, holds regularly scheduled meetings, field trips, and workshops. Their site provides information on the geolgy and natural resources of Ohio.

Cincinnati Dry Dredgers: Website of the Cincinnati Dry Dredgers, an association of amateur geologists and fossil collectors

North Coast Fossil Club: This active group of fossil collectors and enthusiasts of all ages was founded in 1997 and promotes the responsible collection, preparation, and study of fossils through regular meetings and field trips.

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Museums (showing 1 of 1 listings)

Cleveland Museum of Natural History: The museum hosts permanent and temporary exhibits on astronomy, archeology, paleontology, geology, and biology, as well as field trips, educational resources, and on-going research in their collections.

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Colleges and Universities (showing 1 of 1 listings)

Ohio State University Department of Evolution, Ecology and Organismal Biology: General information about the undergraduate and graduate programs in Evolution, Ecology and Organismal Biology at Ohio State University.

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Government Agencies (showing 1 of 1 listings)

Ohio Geological Survey: Search for information on office locations, events, educational resources, maps, and other publications about the geology and natural resources of Ohio.

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Education and Exhibits

Physical Exhibits (showing 1 of 1 listings)

Cincinnati Museum Center at Union Terminal: Museum of Natural History and Science: A description of the exhibits available at the museum, for example a look at Cincinnati's Ice Age: Clues Frozen in Time. Also includes contacts for natural history collections and other general information.

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Virtual Exhibits (showing 1 of 1 listings)

Ohio History Central — Geology: Hosted by the Ohio Historical Society, this site provides information on the geology and paleontology of Ohio.

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Field Guides (showing 1 of 1 listings)

Cincinnati Fossils: This site lists all fossil taxa described or reported from the type Cincinnatian strata (Upper Ordovician) of Ohio, Kentucky, and Indiana, including mollusks, arthropods, echinoderms, brachiopods, and many other groups.

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