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The Cretaceous in Wyoming, US

Cretaceous in Wyoming map

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Cretaceous Fossils

No slide show is available for the Cretaceous in Wyoming.

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Paleontology and geology

Cretaceous rocks are well exposed in many parts of Wyoming, particularly around the edges of the Bighorn Basin and the Black Hills in the northern and northeastern parts of the state, respectively, as well as in the vicinity of Casper in the southeastern part of the state. During the Cretaceous, the Western Interior Seaway developed from the Gulf of Mexico to the Arctic Ocean, spreading over much of the state. Numerous episodes of transgression and regression of this seaway resulted in the deposition of thousands of feet of sedimentary rock, both marine and non-marine. A series of mountain-building episodes (the Laramide Orogeny) to the west and northwest deposited sediments in rivers and streams flowing eastward into the Seaway. These mountain-building events began in the Late Cretaceous and continued into the Tertiary, beginning the formation of the Bighorn, Powder River, and Wind River basins and adjacent mountains. Cretaceous rocks in Wyoming are noted for a wide variety of vertebrate fossils including fish, frogs, salamanders, turtles, crocodiles, pterosaurs, mammals, birds, and, of course, dinosaurs. Bones of Tyrannosaurus, Triceratops, Ankylosaurus, Troodon, Edmontosaurus, Pachycephalosaurus, Edmontonia, Dromaeosaurus, and Ornithomimus have all been recovered in the state.

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Education and Exhibits | Resources

Education and Exhibits

Virtual Exhibits (showing 1 of 1 listings)

Paleo Video: A modern day dinosaur extinction: This video features Mark Goodwin and Jack Horner's research on pachycephalosaurs. They argue that there were fewer pachycephalosaur species in the Hell Creek Formation than we thought - two species, Dracorex hogwartsia and Stygimoloch spinifer, are actually juveniles and teenagers of the species Pachycephalosaurus wyomingensis.

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Field Guides (showing 1 of 1 listings)

Bliss Dinosaur Ranch: This site showcases a large number of Cretaceous fossils (Hell Creek Formation) on a private ranch on the Montana-Wyoming border. The bones of Triceratops and pachycephalosaurs have been found, as well as numerous mammal teeth.

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