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
Wasson Bluff dinosaur tracks, at his Parrsboro Rock and Mineral Shop and Museum. One of them, also found at Wasson Bluff, is a track that may have been made by a primitive, two-legged, crocodile-like creature that was nearly long. In January 1986, American paleontologists Paul Olsen and Neil Shubin announced they had recovered hundreds of thousands of bones at Wasson Bluff, the largest fossil find in North America dating from the geological period 200 million years ago known as the Triassic-Jurassic boundary. It was a time when massive lakes of lava spewed from fissures in the earth as the supercontinent Pangea broke