Diplodocus is a sauropod dinosaur. The name means “double beam”. It was named as such by Othniel Charles Marsh in 1878. The name is in reference to the double-beamed chevron bones found on the underside of the tail. Other diplodocid dinosaurs have these bones. Mamenchisaurus is also known to possess such bones. Diplodocus lived in western North America during the Late Jurassic period. It lived between 154-150 million years ago. Bones of this animal can be found in the Morrison Formation. It lived around other dinosaurs such as Camarasaurus, Barosaurus, Apatosaurus, and Brachiosaurus. Diplodocus was a giant animal measuring in at 35 meters (115 ft) in length. Mass estimates put Diplodocus at any where between 10 to 16 tons. During Eric Kirby‘s isolation on Site B, he ran into a family of Diplodocus and used one as a water slide of sorts.