Land reptiles of Middle and Upper Triassic age are known from many widely separated localities in the United States, but chiefly from the extensive “red beds” of the Rocky Mountain region. The fossils from these beds occur for the most part at least in the horizon called the Shinarump. Its age is usually considered to be Upper Triassic, but the character of the fossils seems to indicate possibly the Middle Triassic. Aside from the stereospondylian amphibians, the last of the Stegocephalia, the vertebrates from this horizon and these regions are chiefly Phytosauria. A few anomodonts, or what seem to be anomodonts—the only record of their occurrence outside of Africa—are known from Wyoming and Utah. And a single specimen from the Wind River red beds, described by the writer as _Dolichobrachium_, may represent reptiles allied to the dinosaurs. Phytosaur fossils of this horizon have been discovered in Utah, the Wind River Mountains, and near Laramie City in Wyoming; in southwestern Colorado; in western Texas; and in various places in New Mexico and Arizona. Doubtless when these fossiliferous beds are more thoroughly explored many new and interesting reptiles will be discovered. Phytosaur remains, probably of about the same age as the Rocky Mountain ones, have long been known from the Triassic of North Carolina. From somewhat more recent Triassic deposits in Connecticut and Massachusetts, several skeletons of small carnivorous dinosaurs, and various parasuchian remains have been described by Marsh, Lull, and Talbot. And these beds have long been famous in Massachusetts for their footprints, for the most part originally referred to birds, but now pretty well known to have been made by dinosaurs and amphibians. No vertebrate fossils of Lower or even Middle Jurassic age are known from North America. From the Baptanodon beds of Wyoming, limestones of about two hundred feet in thickness, four genera of plesiosaurs, the very peculiar ichthyosaur from which the beds take their name, and a few bones of an ancient crocodile are known. Immediately overlying the Baptanodon beds, the Morrison beds, of from two hundred to four hundred feet in thickness, probably of Uppermost Jurassic and Lowermost Cretaceous age, have yielded an exceedingly rich vertebrate fauna, consisting chiefly of dinosaurs. Discovered first in the vicinity of Morrison, Colorado, in 1877, hundreds of tons of bones have been collected from these beds for various museums. The dinosaurs include many genera of all three suborders, varying in size from that of a cat to some of the largest known land animals. Of other reptiles a very few jaws of a true rhynchocephalian, a fragment of a wing bone of a pterodactyl, numerous turtles, and crocodiles, only, are known. The beds are predominantly black-clay shales, intercalated with sandstones, and all are of fresh-water origin.