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Illinois, US



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State Fossil:
State fossil from Illinois

Tullimonstrum gregarium
The Tully monster is an enigmatic, worm-like creature that lived in the shallow seas covering most of western North America, roughly 300 million years ago. Its fossils have not been found anywhere else in the U.S. or the world.

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Paleontology and geology

The Precambrian: All Precambrian rocks of Illinois are deeply buried below the surface. They consist primarily of volcanic and granitic intrusions, and thus do not contain fossils.

The Paleozoic: During much of the Paleozoic, the state was covered by a shallow sea, and the fossil record indicates a rich and diverse marine fauna from the Cambrian through the Early Carboniferous. During the Late Carboniferous, a large river delta system dominated most of Illinois. The swamps on this delta were inhabited by a tremendous variety of plants and animals, now referred to as the Mazon Creek flora and fauna. These swamps provided the carbon that today forms the coal beds mined in Illinois. There are no rocks of Permian age in the state.

The Mesozoic: There are very few Mesozoic rocks in Illinois. The state was mostly above sea level and subject to erosion during this time. There are small exposures of Cretaceous rocks, but the only fossils found have been some foraminifera and leaf fossils.

The Cenozoic: There are only sparse exposures of Tertiary rock in southernmost Illinois, and few fossils have been recovered from them. The Cenozoic is represented mainly by Quaternary glacial deposits covering most of the state. The exceptions are the areas to the west and in the southern part of the state, which were glacier-free. There is a rich Quaternary fossil record that includes giant beaver, mastodon, mammoth, and the stag moose.

Links to more on Illinois paleontology

Organizations | Education and Exhibits | Research and Collections | Resources


Museums (showing 1 of 1 listings)

Burpee Museum of Natural History: The mission of Burpee Museum of Natural History is to inspire all people to engage in a lifetime of learning about the natural world.

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Government Agencies (showing 1 of 1 listings)

Illinois State Geological Survey: A great resource for information, maps, and publications on the paleontology, geology, and natural resources of Illinois.

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Education and Exhibits

Virtual Exhibits (showing 3 of 5 listings)

Mazon Creek Virtual Exhibit- University of California Museum of Paleontology: This page has more detailed information and additional links on the fossils at Mazon Creek, as well as the rocks, environment, plants, and animals of the Carboniferous.

Mazon Creek Fossils: Hosted by the Illinois State Museum in Springfield, IL, this site is a great resource for information on the rocks, fossils, and history of the Mazon Creek area, including many excellent images.

Sue at Chicago's Field Museum of Natural History: Excavated in South Dakota and now on display in Chicago, Sue is the world's largest, most complete, and best preserved Tyrannosaurus rex. Take a tour of this website for detailed information about Sue.

More Virtual Exhibits

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Events and Programs (showing 2 of 2 listings)

Project Exploration: Project Exploration was founded to make science accessible to the public– with a special focus on city kids and girls. The program includes: Youth Development Initiatives targeting minority and female Chicago Public School students, Services for Schools and Teachers, and Public Exhibitions and Online Initiatives. 

Evolving Planet: Evolving Planet takes visitors at the Field Museum on an awe-inspiring journey through 4 billion years of life on Earth, from single-celled organisms to towering dinosaurs and our extended human family.

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Research and Collections

Researchers (showing 1 of 1 listings)

Dr. Thomas W. Kammer: Specialty: Evolutionary paleoecology of Paleozoic crinoids, plus lithostratigraphy, biostratigraphy, and sequence stratigraphy of marine Mississippian rocks in the east-central United States. Field areas include West Virginia, Kentucky, Indiana, Illinois, Missouri, and Iowa.

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Image Collections (showing 1 of 1 listings)

Ordovician Fossils in Ogle County, Illinois: An amateur collection of fossils gathered at various sites in Illinois, primarily Ordovician.

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Maps (showing 1 of 1 listings)

Illinois State Geological Survey, Quaternary Deposits Map: Map showing the extent of the Quaternary glacial deposits covering Illinois.

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