Fruita, Colorado Riggs and crew found nearly two thirds of an "Apatosaurus excelsus" skeleton (commonly known as a Brontosaurus) on the northeast side of Dinosaur Hill, in Fruita. This is still considered to be one of the finest specimens known. Later, other sauropod bones were also found, which eventually led to the landmark's name. The animals were from the late Jurassic Age (150 million years ago) and within the Morrison Formation. Fossils of the "Fruitadens" (a heterodontosaurid dinosaur), the world's smallest known plant-eating dinosaur, were first found in the Fruita Paleontological Area (within the McInnis Canyons National Conservation Area) off Kings View
Apatosaurus the time of the creature's maturity. This was first noted in 1903 and again in 1936. Long-bone histology enables researchers to estimate the age that a specific individual reached. A study by Eva Griebeler etal. (2013) examined long-bone histological data and concluded the "Apatosaurus" sp.SMA0014 weighed , reached sexual maturity at 21years, and died aged 28. The same growth model indicated "Apatosaurus" sp.BYU 601–17328 weighed , reached sexual maturity at 19years, and died aged 31. Compared with most sauropods, a relatively large amount of juvenile material is known from "Apatosaurus". Multiple specimens in the OMNH are from juveniles of an