Assertion: dinosaur's fossil | /r/AtLocation | western united states
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text: Allosaurus, (genus Allosaurus), subsumes Antrodemus, large carnivorous dinosaurs that lived from 150 million to 144 million years ago during the Late Jurassic Period; they are best known from fossils found in the western United States, particularly from the Cleveland-Lloyd Quarry in Utah and the Garden Park Quarry in Colorado.