The oldest, most remote fossil beds in the area are at the base of the John Day River's canyon. The 40-million-year-old Clarno Unit exposes mud flows that washed over an Eocene-era forest. The Clarno Formation eroded into white cliffs topped with spires and turrets of stone. There are three half-mile (round-trip) interpretive trails, including one that passes through large boulders containing fossils of an ancient forest, and another that leads to the base of Palisades Cliff and some petrified logs.
