Fossils of the saurischian plant-eaters are found much more frequently than those of flesh-eaters and are usually in sedimentary rocks which contain beds of clam shells. For this reason it seems probable that they waded lagoons and streams, feeding on aquatic and bank-side vegetation. The suggestion has been made that the larger dinosaurs could not even walk on dry land because their weight would have crushed the bones of their feet; they needed the buoyancy of water to help support them. However, footprints of a huge dinosaur, much larger than any from the quarry, have been found near Glenrose, Tex. The large footprints were made on a sandy beach of a sea in Lower Cretaceous time. Thus we know that they could walk on dry land if they wanted to. All of the dinosaurs of the order _Ornithischia_ were plant-eaters, and were of both two- and four-footed types. The two-footed types found in the quarry are _Camptosaurus_, _Dryosaurus_, and _Laosaurus_. These forms had well developed front legs, though much shorter than their hind legs, which suggests that they may have dropped down on “all fours” while feeding or resting. The teeth were small, chisel-shaped, and fitted only for cropping vegetation. The larger specimens of _Camptosaurus_ reached a length of 17 feet but _Laosaurus_ was only 2½ feet long. _Stegosaurus_ is the only quadruped (four-footed) of this order found in the quarry. It had long hind legs and very short front legs. It reached a length of 18 to 20 feet and was 10 to 11 feet high over the hips. The most characteristic feature of this form was the double row of bony plates down the back and the group of spikes at the end of the tail. The teeth were similar to those of _Camptosaurus_, but much more numerous. Only two other groups of reptiles have been found in the quarry at Dinosaur National Monument and their remains are rare. These are the crocodiles and turtles. Two crocodiles are known; the larger one, _Goniopholis_, was about the size of existing alligators and did not differ in external appearance from present-day crocodiles. The smaller one was less than a foot long and resembled a 2 weeks’ old alligator as much as anything. However, we know from the texture of the surface of the bone that it was not a young animal. The turtle, _Glyptops_, was about the same size and general appearance as the pond turtles of today. WHY SO MANY? The partial skeletons of more than 20 individual dinosaurs and the scattered bones of about 300 more have been discovered in the Dinosaur Quarry. Many of the best specimens may be seen today at museums of natural history in the larger cities of the United States and Canada. The quarry is easily the largest and best preserved deposit of Jurassic dinosaurs known today.