differences. Works Cited 1) Carroll, R. L. 1988. Vertebrate Paleontology and Evolution. W. H. Freeman and Company, New York. 2) http://www.trueauthority.com/dinosaurs/about.htm 3) Dr. Robert Riesz, University of Toronto, “Ceratopsia and Ornithopoda” http://www.erin.utoronto.ca/~w3bio356/lectures/ceratopsia_and_ornithopoda.html 4) Enchanted Learning; “Pachycephalosaurus” http://www.enchantedlearning.com/subjects/dinosaurs/dinos/Pachy.shtml 5) American Museum of Natural