2 PROCEEDINGS OF THE NATIONAL MUSEUM vol.81 



ings, which conform to the shape of the underside of the vertebrae, 

 these in turn being supported by a number of pipe uprights securely 

 anchored in the base. The vertebral supports were cast in 6-foot 

 lengths and after being placed in final position were welded to- 

 gether into one continuous piece. The limbs and other bones are sup- 

 ported by half-round irons with the flat side fitted to the inequalities 

 of the bones. All the ironwork is camouflaged to the variegated 

 color of the specimen so as to render the supporting work as incon- 

 spicuous as possible. 



The present specimen is a fully adult animal and, except for the 

 missing portions, is an excellent example of its kind. 



COLLECTING THE SPECIMEN IN THE DINOSAUR NATIONAL 



MONUMENT 



In the Uinta Basin in northeastern Utah, near Jensen, Uinta 

 County, an 80-acre tract of land has been set aside as a part of the 

 national park system under the name of Dinosaur National Monu- 

 ment. This reservation, as may be inferred, contains an extensive 

 and important deposit of dinosaurian fossils. 



The history of the Dinosaur National Monument had its begin- 

 ning in 1909 with the discovery of dinosaurian fossils by Earl 

 Douglass, of the Carnegie Museum. During the first six years 

 of work there such an abundance of well-preserved specimens was 

 found that in 1915, at the instigation of Dr. W. J. Holland, then 

 director of the Carnegie Museum, the Secretary of the Interior with- 

 drew this area from the public domain as a national monument in 

 order to conserve this important deposit of fossils. Governmental 

 permission to continue their excavations, however, was granted from 

 year to year up to the close of 1922, when the quarry was abandoned. 

 In the 13 consecutive years that operations were carried on there bj^ 

 the Carnegie Museum, a great mass of material, some 300 tons in 

 all, I am told, was collected. In those collections were many artic- 

 ulated skeletons of both large and small dinosaurs, and especially 

 important was the recovery of a considerable series of well-preserved 

 skulls, the rarest and most sought for part of the dinosaurian skele- 

 ton. The great diversity of forms represented, together with their 

 unusually perfect and excellent preservation, marks this as the most 

 remarkable deposit of Morrison fossils ever discovered. 



The principal fossil-bearing horizon is a heavy, greenish, con- 

 glomeratic, cross-bedded sandstone that occurs in the upper half of 

 the Morrison formation. The Morrison in this section, according to 

 measurements made by Dr. J. B. Reeside, jr.,^ has a total thickness of 

 795 feet, made up of the usual alternating beds of shale and sand- 



1 U. S. Geol. Surv. Prof. Paper 132C, pp. 44-45, 1923. 



