Morrison Formation, a geological formation in Utah, USA. This formation dates back to the Late Jurassic Period, which was approximately 155 to 148 million years ago. The area is known for its extensive fossil discoveries, particularly of dinosaurs and other ancient organisms. Most of the fossils are found in the green siltstone beds and lower sandstones, which are remnants of the rivers and floodplains of the Jurassic period. The Morrison Formation is made up of layers of sedimentary rock, including sandstone, mudstone, and limestone. It covers an area of 1.5 million square kilometres, but only a small portion of it is accessible to geologists and palaeontologists. Some of the notable dinosaur fossils found in the Morrison Formation include large herbivores like Apatosaurus, Diplodocus, and Stegosaurus, as well as carnivorous dinosaurs like Allosaurus.