Originally, from 1909 to 1922, the Hogback Ridge at Split Mountain was worked by American paleontologist Earl Douglass (1862–1931) for the Carnegie Museum (the site was called the Carnegie Quarry). On October 4, 1915, President Woodrow Wilson designated the spot as Dinosaur National Monument—because of its importance to paleontology and to stop any future development of the area.

In 1909, Douglass found the dorsal bones of an Apatosaurus at this site; it took six more years to remove the skeleton from the rock and mount it at the Carnegie Museum. After 1922, Douglass worked the quarry for two more years (for the University of Utah and the Smithsonian Institution) finding a Diplodocus that is currently mounted at the Smithsonian. Today, tourists at the visitors center at Hogback Ridge can view the quarry face that acts as the north wall of the building; the bones were left in place after the overlying rocks were removed.