Apatosaurus opponent of Marsh and his taxa, labeled the "Apatosaurus" mount of the American Museum of Natural History "Brontosaurus". Because of this decision the name "Brontosaurus" was commonly used outside of scientific literature for what Riggs considered "Apatosaurus", and the museum's popularity meant that "Brontosaurus" became one of the best known dinosaurs, even though it was invalid throughout nearly all of the 20th and early 21st centuries. It was not until 1909 that an "Apatosaurus" skull was found during the first expedition, led by Earl Douglass, to what would become known as the Carnegie Quarry at Dinosaur National Monument. The skull
Cleveland-Lloyd Dinosaur Quarry Cleveland-Lloyd Dinosaur Quarry The Cleveland-Lloyd Dinosaur Quarry, well known for containing the densest concentration of Jurassic dinosaur fossils ever found, is a paleontological site located near Cleveland, Utah, in the San Rafael Swell, a part of the geological layers known as the Morrison Formation. Well over 15,000 bones have been excavated from this Jurassic excavation site and there are many thousands more awaiting excavation and study. It was designated a National Natural Landmark in October 1965. All of these bones, belonging to different species, are found disarticulated and indistinctly mixed together. It has been hypothesised that this strong concentration of