• Two

    John Day Fossil Beds

    National Monument Oregon

Geologic Formations

The rock layers of the John Day Fossil Beds spread far beyond the boundaries of the National Monument.
 
Image of a map of Oregon with the geological formations shown in different colors.
The fossil bearing rocks of the John Day basin are wide spread.
 
Image of the John Day Fossil Beds timeline.

Rocks at the fossil beds are stacked up like layers of a cake.Click on the timeline for a larger version.

The oldest layers are on the bottom, the youngest layers are on the top.

To learn more about each of these different Formations click on the links in the index on the left side of this page. They are (from youngest to oldest) the Rattlesnake, Mascall, John Day strata, and Clarno formations.

For a condensed, printer friendly version, download Geology of John Day Fossil Beds, a pdf handout designed to be printed on legal paper (8.5x14 inches.) Paper copies are available at the Thomas Condon Paleontology Center.

The Sheep Rock Geology diagram, designed to be printed on letter paper (8.5x11 inches) is useful to help decipher the geology of the river valley near Sheep Rock, where rock layers have shifted around due to faulting and have been eroded by the river. Paper copies are available at the Thomas Condon Paleontology Center.

Did You Know?

Crocodiles in oregon?

Fossils from the Clarno Unit show that 44 million years ago, in what is now a near desert in Oregon, crocodiles and palm trees flourished.