The "dinosaur rush" that followed was fueled by a rivalry between E.D. Cope of Philadelphia and O.C. Marsh from Yale University, two famous paleontologists who competed to discover and name the most dinosaurs. Numerous sites, mostly in Colorado (Morrison, Canon City) and Wyoming (Como Bluff, Bone Cabin Quarry, Howe Quarry) yielded abundant remains of Jurassic dinosaurs during the closing decades of the nineteenth century. Utah, however, remained out of the picture, until Douglass' fateful discovery in August of 1909. Along a hogback (a ridge formed from steeply tilted strata) near Split Mountain, Douglass found a series of eight large vertebrae (backbones) weathering out of a resistant sandstone layer of Morrison Formation. These vertebrae were from the tail of the sauropod dinosaur Apatosaurus, and would prove to be part one of the most complete skeletons of Apatosaurus ever discovered. More importantly, this site would also prove to be probably the most prolific dinosaur quarry of the Morrison Formation.