Makuleke Gorge and in these can be found fragments of bone and probably wood representing both holdovers from the Permian–Triassic extinction event like glossopetrids (a type of tree) and dicynodonts (a form of mammal-like reptile), and new forms that would dominate the Mesozoic, including modern conifers, cycads and of course dinosaurs, such as "Euskelosaurus". Most of the sandstones in the Pafuri region however probably represent the great age of dinosaurs – the Jurassic and Cretaceous Periods. During the early parts of the Jurassic, which lasted from approximately 210 million years ago until about 144 million years ago, the area was almost
John Day Fossil Beds National Monument originated during the late Jurassic and early Cretaceous, about 118 to 93 million years ago. Northeastern Oregon was assembled in large blocks (exotic terranes) of Permian, Triassic, and Jurassic rock shifted by tectonic forces and accreted to what was then the western edge of the North American continent, near the Idaho border. By the beginning of the Cenozoic era, 66 million years ago, the Blue Mountains province was uplifting (that is, was being pushed higher by tectonic forces), and the Pacific Ocean shoreline, formerly near Idaho, had shifted to the west. Volcanic eruptions about 44 million years ago during the