dinosaur species can be found here, including relatives of Camarasaurus such as Diplodocus, Apatosaurus, and Brachiosaurus, but camarasaurs are the most abundant of the dinosaurs in the formation. Camarasaurus fossils have been found in almost every major locality and have one of the greatest known distributions of Morrison dinosaurs, with fossils found in localities from New Mexico to Montana and Utah to Oklahoma. According to radiometric dating, the Morrison sedimentary layers range between 156.3 million years ago (Mya) at the base, to 146.8 Mya at the top, which places it in the late Oxfordian, Kimmeridgian, and early Tithonian stages of the Late Jurassic period. Its environment is interpreted as semiarid with distinct wet and dry seasons. Dinosaur and trace fossils are found particularly in the Morrison Basin, which stretches from New Mexico to Alberta and Saskatchewan and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west. Eroded material from their east-facing drainage basins was carried by streams and rivers and deposited in swampy lowlands, lakes, river channels, and floodplains. The formation is similar in age to the Lourinha Formation in Portugal and the Cañadón Calcáreo Formation in Argentina, Camarasaurid fossils have been found at the 2 formations. In 1877, it became the center of the Bone Wars, a fossil-collecting rivalry between early paleontologists Othniel Charles Marsh and Edward Drinker Cope, with Camarasaurus itself being discovered and named by the latter Paleontologist during the conflict. Paleofauna The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs such as Maraapunisaurus, Amphicoelias, Barosaurus, Diplodocus, Apatosaurus, Brontosaurus, and Brachiosaurus. Dinosaurs living alongside Camarasaurus included the herbivorous ornithischians Camptosaurus, Gargoyleosaurus, Dryosaurus, Stegosaurus, and Nanosaurus. Predators in this paleoenvironment included the theropods Saurophaganax, Torvosaurus, Ceratosaurus, Marshosaurus, Stokesosaurus, Ornitholestes, and Allosaurus, which accounted for up to 75% of theropod specimens, and was at the top trophic level of the Morrison food web. Camarasaurus is commonly found at the same sites as Allosaurus, Apatosaurus, Stegosaurus, and Diplodocus. Other organisms in this region included bivalves, snails, ray-finned fishes, frogs, salamanders, turtles, sphenodonts, lizards, terrestrial and aquatic crocodylomorphans, and several species of pterosaurs such as Harpactognathus and Mesadactylus. Early mammals present were docodonts (such as Docodon), multituberculates, symmetrodonts, and triconodonts. The flora of the period has been revealed by fossils of green algae, fungi, mosses, horsetails, cycads, ginkgoes, and several families of conifers. Vegetation varied from river-lining