In August 1909 palaeontologist Earl Douglass discovered a 200-foot long sandbar which was layered with prehistoric plant and animal fossils. Since then about 350 tons of fossils, including full skeletons and remains of some previously unknown dinosaur species were excavated by Douglass and his crew from the quarry built on the site. A year-round visitor centre has been built to protect the quarry and its fossilised dinosaur bones.
You can watch palaeontologists chip away the sandstone to expose the fossilised dinosaur bones and the preparation laboratory where dinosaur fossils are cleaned and preserved for future generations. Dinosaur National Monument stretches east into Colorado.