John Day Fossil Beds National Monument
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Location: Grant County, Oregon
Time: 50 to 6 million years ago, during the Tertiary period
About this Famous Find: Located in central Oregon, John Day Fossil Beds National Monument records over 40 million years of earth history, from the Eocene (45 million years ago) to the Pliocene (5 million years ago). Within its rocks we find a diverse animal and plant record. The paleontological record at John Day spans such a long time and represents so many different paleoenvironments that paleobotanist R.W. Chaney declared that “no region in the world shows more complete sequences of Tertiary land populations, both plant and animal, than the John Day Basin.”
The exposed rocks exposed have been divided into four geologic formations:
The Clarno Formation (50–35 million years ago): Fossil nuts, seeds, fruit, leaves, branches, and roots from various plants are very well-preserved and indicate a tropical to subtropical climate. Also found are many different and strange-looking animals. Some, such as brontotheres and amynodonts, fed on plants while others, such as the hyaenadonts and early cats, fed on the herbivores.
The John Day Formation (37–20 million years ago): Plant fossils indicate that as the climate cooled, deciduous forests and prairies replaced the earlier tropical forests and provided habitats for a more diverse fauna, including rhinoceroses, horses, camels, dogs, cats, pigs, oreodonts, and rodents.
The Mascall Formation (15–12 million years ago): After a long period of volcanic eruptions, the resulting basalt flows eroded into fertile soils that nourished lush forests and grasslands, supporting an even greater diversity of animals, including horses, camels, deer, bears, weasels, dogs, and cats, as well as larger mammals like the gomphotheres (early elephants), rhinoceroses and bear-dogs.
The Rattlesnake Formation (8–6 million years ago): These coarse deposits indicate a time of grasslands, floodplains, and rivers and contain fragmented remains of horses, sloths, rhinoceroses, camels, peccaries, pronghorns, dogs, bears, and others.
Education and ExhibitsParks (1 listing)
John Day Fossil Beds National Monument: The official National Park Service site has information on when and how to get to the monument, what to see and do, camping and lodging, as well as maps and books for sale.
Virtual Exhibits (1 listing)
Paleo Video: Kaitlin Maguire at the John Day Fossil Beds: Watch this video and join University of California Museum of Paleontology graduate student Kaitlin Maguire on a field trip to the John Day Fossil Beds National Monument! After visiting the park in 2009, Kaitlin decided that it was the perfect place to do her dissertation research.
