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
The Unknown Known I know." "The Unknown Known" was screened in the main competition section at the 70th Venice International Film Festival, and premiered at the Telluride Film Festival on August 29, 2013. The documentary has an 84% approval rating on the review aggregator website Rotten Tomatoes, based on 105 reviews with an average rating of 8.2/10. The website's critical consensus reads, "Viewers hoping to see Donald Rumsfeld admit making mistakes in public office may find "The Unknown Known" frustrating – but no less fascinating." On Metacritic, the film has a weighted average score of 69 out of 100, based on 30 critics,