The oldest, most remote fossil beds are in magnificent palisade formations at the base of the John Day River's canyon. There are three, quarter- to half-mile (round-trip) interpretive trails, including one that passes through large boulders containing the fossils of an ancient forest and another that leads to an arch and some petrified logs. All trails lead from the base of the palisades. The Clarno Unit is 20 miles west of Fossil on Hwy 218.
The 40-million-year-old Clarno Unit exposes mudflows that washed over an Eocene-era forest and eroded into white cliffs topped with spires and turrets of stone.
