a sandstone and mudstone formation in Southern Utah, comprising layers dating between 76.6 and 74.5 Ma and overlying the Wahweap Formation. One of the most productive sites for plants and animals of the Campanian age, it has yielded crocodiles, turtles, and especially herbivorous horned dinosaurs such as Kosmoceratops richardsoni (found only here) and Nasutoceratops titusi; hadrosaurs, also herbivores, are common, as well as several other very large species. The tyrannosaurid Teratophoneus curriei is among the predators in the formation. Many of the specimens are complete, such as several whole dinosaur skeletons and a turtle that died with many eggs in her body. The United States, Late Cretaceous.