Mounting Skeleton of Diplodocus in Exhibition Hall, 1930, Smithsonian Institution Archives, USNM's Diplodocus specimen, as it was under construction in the Vertebrate Paleontology Hall in 1930-1931. The bones were collected mostly in the Dinosaur National Monument in Utah in 1923, and over the next seven years were prepared and mounted primarily by Norman H. Boss and Thomas Horne, under the scientific direction of Charles W. Gilmore..