The Jurassic deposits of Western North America contain the remains of many gigantic Dinosaurs, and various skeletons of these have been obtained by the writer, who has described the more important forms. Restorations of the skeletons of three of the most interesting genera, Brontosaurus, Stegosaurus, and Ceratosaurus, have already been given in the American Journal of Science and in this Magazine, and another of these huge reptiles is thus represented on Plate VI.