Thin at one end, thicker in the middle, then thin again at the other end, Brontosaurus is one of the most famous dinosaurs. So why do paleontologists call it Apatosaurus? Othniel Charles Marsh coined both names from two relatively complete specimens in the late 1870s. Additional specimens collected during the second American Jurassic dinosaur rush (1895-1905) provided the material for revisions. Henry Fairfield Osborn, who detested Marsh, systematically sought to overturn his work. Yet it was Elmer Samuel Riggs who showed that Marsh's Apatosaurus and Brontosaurus are synonymous, and Osborn who stubbornly, and inexplicably, adhered to the latter.