Figure 8. Paleogeography of North America during the Late Cretaceous (∼75 Ma), showing biogeographic distribution of chasmosaurine ceratopsid dinosaurs on the western landmass, Laramidia, during the late Campanian (∼76–73 Ma).

Green represents coastal and alluvial plain habitats and reddish brown represents highlands. Present day boundaries of states and provinces are noted, as are the locations of key dinosaur-bearing geologic formations. Abbreviations: A, Aguja Formation, Texas; D, Dinosaur Park Formation, Alberta; F, Fruitland-Kirtland Formations; K, Kaiparowits Formation, Utah). Modified after Blakey [1].