Ochoco Mountains made of rocks from the Permian, Triassic, and Jurassic periods (300 to 200 million years old) that were transported by the Pacific Plate and accreted in the late Mesozoic era (about 100 million years ago) as part of a vast shallow sea, then slowly uplifted by volcanic eruptions during the Eocene epoch (50 to 37 million years ago) to form the Clarno Formation. From 37 to 17 million years ago, eruptions in the western Cascade Range spread ash across eastern Oregon, forming the John Day Formation. From 17 to 14 million years ago, major volcanic eruptions covered much of the
Late Triassic the impact of an asteroid, climate change, or rising sea levels. The Carnian Age is the first stage of the three to occur during the duration of the mass extinction era. The Carnian age developed about 228 to 217 million years ago, and signals the start of the Late Triassic Epoch. The Carnian stage can further be broken down to relative species activity during the time, based on fossils and evidence found dating back to this time period. For example, marine life such as "serenites nanseni" and "Trachyceras Obesum" can be dated back to the early Carnian stage. Meanwhile, "Tropites