Geology Reference
In-Depth Information
Lava-topped Sheep Rock is one of the landmarks in the heart of the fossil beds, where pre-historic
animals roamed in a tropical climate 25 million years ago (photo courtesy Oregon State Highway
Department).
At Castle Rock north of Picture Gorge, crenellated spires and columns typically result from erosion of
the John Day sediments (photo courtesy of Oregon State Highway Department).
