Apatosaurus "Apatosaurus" may have been more solitary than other Morrison Formation dinosaurs. Fossils of the genus have only been found in the upper levels of the formation. Those of "Apatosaurus ajax" are known exclusively from the upper Brushy Basin Member, about 152–151 mya. "A.louisae" fossils are rare, known only from one site in the upper Brushy Basin Member; they date to the late Kimmeridgian stage, about 151mya. Additional "Apatosaurus" remains are known from similarly aged or slightly younger rocks, but they have not been identified as any particular species, and thus may instead belong to "Brontosaurus". The Morrison Formation records a
Alan the Dinosaur vertebra encased within sandstone and measuring 145 mm in length. The fossil first went on public display in the Yorkshire Museum in June 2015. It was redisplayed as part of the "Yorkshire's Jurassic World Exhibition", which opened in March 2018. The exhibition features a virtual reality experience in which users can feed a digital reconstruction of Alan. Alan the Dinosaur Alan the Dinosaur is the name given to an unidentified Sauropodomoph fossil, found in Whitby in 1995, regarded as the oldest sauropod dinosaur found in the United Kingdom. It is now in the Yorkshire Museum. The fossil was discovered in