Mounted replica of a composite skeleton of Edmontosaurus annectens on display at the University of Oxford Museum, Oxford, England. The original skeleton is compiled from disarticulated fossil bones from a bonebed of the Hell Creek Formation, exposed in the Ruth Mason Quarry in Harding County, South Dakota. It is 8.5 m (28 ft.) long and the skull is almost 1 m (39 in.) in length.[1][2] ↑ Dinosaurs in the Museum. Oxford University Museum of Natural History (brochure, PDF), p. 7 ↑ BHI Fossil Replica Catalog 2012. Black Hills Institute of Geological Research, Inc., Hill City, SD, 2012 (PDF), p. 22