Within a year, Douglass and his men had run a cut over a hundred feet long in the hard sandstone, digging down along the almost perpendicular slant of the rock. At the base of this, rails were laid and small mine carts introduced to haul away the cuttings from the rapidly developing quarry. New specimens appeared: A small plant-eating dinosaur known as _Dryosaurus_; an armored form called _Stegosaurus_; and another large creature like the _Apatosaurus_. Best of all, the _Apatosaurus_ No. 1 was well on its way out of the rock and would soon be ready to ship to the Carnegie Museum in Pittsburgh. [Illustration: “... I SAW EIGHT OF THE TAIL BONES OF A _Brontosaurus_ IN EXACT POSITION.” (FROM DOUGLASS’ DIARY, 1909. SHOWN IN PHOTO IS DOUGLASS’ ASSISTANT, ELDER GOODRICH.)] [Illustration: THE FIRST CUT IN THE QUARRY, AS IT LOOKED IN 1910. (COURTESY, A. S. COGGESHALL.)] [Illustration: SAMPLE VIEW OF DINOSAUR REMAINS AS THEY WERE UNCOVERED IN THE QUARRY. THIGH BONE NEAR MAN. (COURTESY, A. S. COGGESHALL.)] [Illustration: QUARRY OPERATIONS. SAURISCHIAN PLASTERED PELVIS UPPER CENTER. (COURTESY, A. S. COGGESHALL.)] In 1913, after 3 years of laboratory work in the Carnegie Museum the big _Apatosaurus_ was on its feet in the Hall of Vertebrate Paleontology—1 of the 4 mounted specimens of this genus in the country and the most perfect of all. Prepared and erected by Arthur S. Coggeshall and his associates, it measures 71½ feet long and stands 15 feet tall at the arch of the back. As the excavating progressed it was not long before the diggings became what is known to the profession as a “general quarry.” Dinosaurs of “all kinds and sizes” were showing up. Other quarries of this type had been developed in previous years in the Morrison formation at Como Bluff, Wyo., and Canon City, Colo., but they contained nothing like the variety of forms found here. Moreover, these at the monument were better preserved and the skeletons more intact. The remains most frequently encountered in the diggings were those of sauropods—the huge plant-feeding dinosaurs with long tapering extremities that lumbered about on four pillar-like legs. _Camarasaurus_ and the larger _Apatosaurus_ were typical members of this group, and their numerous bones show them as being common animals of their time. More common were the _Diplodoci_, of the exaggerated neck and even longer whiplash tail. This genus distinguished itself by producing not only the largest amount of skeletal material from the quarry, but also the largest number of skulls—those rarest of fossils. One skull was found in exact position with the neck bones, which settled all doubts as to the details of this animal’s head piece. The longest _Diplodocus_ to come from the monument extended 75½ feet.