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John Day Fossil Beds National MonumentImage of blue basin.
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John Day Fossil Beds National Monument
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 highlights at the right hand side of the page.
Image of rock from the Rattlesnake Group.
A buried grassland 8-6 million years old.
Learn more about the rocks of the Rattlesnake assemblage!
more...
Image of rock from the Mascall assemblage.
15-12 million year old ash beds.
Learn more about the rocks from the Mascall assemblage!
more...
Image of the rock from the Turtle Cove assemblage of the John Day Group
Layers of volcanic ash, 18-39 miliion years old.
Learn more about the rocks of the John Day Strata!
more...
Image of the rock from the Clarno assemblage.
54-37 million years ago a jungle was here.
Learn more about the rocks in the Clarno assemblage!
more...
Image of a running rhino from the clarno formation  

Did You Know?
Some of the earliest rhino fossils in the world were found in the John Day beds. We call these the "running rhinos".

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Last Updated: January 13, 2007 at 18:23 EST