Cascade-Siskiyou National Monument

From the U.S. Department of the Interior:

The Cascade-Siskiyou National Monument is the nation’s first monument designated in recognition of the area’s biological diversity. The monument’s remarkable ecology is a product of its location at the crossroads of two different mountain ranges. The ancient Siskiyou mountains contain some of the oldest rocks in Oregon, over 425 million years old. Comparatively, the Cascades are children, born by volcanic forces only 40 million years ago. The land and wildlife here are national treasures.