The Hell Creek Formation in what’s now the Dakotas, Montana, and Wyoming was once home to some of the world’s most beloved dinosaurs, like Triceratops and Tyrannosaurus rex (including SUE, one of the largest, most complete, and best-preserved T. rex specimens ever found). The Hell Creek Formation in what’s now the Dakotas, Montana, and Wyoming was once home to some of the world’s most beloved dinosaurs, like Triceratops and Tyrannosaurus rex (including SUE, one of the largest, most complete, and best-preserved T. rex specimens ever found). Paleontology & Fossils Phys.org – latest science and technology news stories