The dinosaur fossil beds (bone beds) were discovered in 1909 by Earl Douglass, a paleontologist working and collecting for the Carnegie Museum. He and his crews excavated thousands of fossils and shipped them back to the museum in Pittsburgh, Pennsylvania for study and display. President Woodrow Wilson proclaimed the dinosaur beds as Dinosaur National Monument in 1915. The monument boundaries were expanded in 1938 from the original tract surrounding the dinosaur quarry in Utah, to its present extent of over 200,000 acres (800 km²) in Utah and Colorado, including the spectacular river canyons of the Green and Yampa.