Open jaw of Pliosaur Skull. Lots of teeth.
The skull of a plesiosaur (extinct marine reptile) discovered at Glen Canyon National Recreation Area

The rocks of Glen Canyon National Recreation Area preserve a complex story of life on Earth dating back over 300 million years. Hidden within these sandstone layers are the remains of extinct amphibians that sported giant sail-like protrusions on their backs, the footprints of dinosaurs straight out of Jurassic Park, and dung from Ice Age megafauna like mammoths and giant ground sloths. Information hidden within the barren rocks found here today hint to massive changes to a land that was at one time a shallow sea, an expansive sand dune, even expansive swamp lands. The stories hidden within these rocks are diverse, complicated, and extremely valuable to scientists. They provide us with valuable information that helps us to not only reconstruct the ancient environments and animal communities of northern Arizona and southern Utah, but to connect Glen Canyons story with the countless others preserved all over the world.


Mesozoic Fossils

Read a summary of Mesozoic Era (made up of Triassic, Jurassic, and Cretaceous Periods) fossils in Glen Canyon.

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3 minutes, 38 seconds

Glen Canyon and Rainbow Bridge contain a rich abundance of geologic formations. Learn about the significance of fossils found within these formations.


Last updated: April 28, 2023

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Contact Info

Mailing Address:

PO Box 1507
Page, AZ 86040


928 608-6200
Receptionist available at Glen Canyon Headquarters from 7 am to 4 pm MST, Monday through Friday. The phone is not monitored when the building is closed. If you are having an emergency, call 911 or hail National Park Service on Marine Band 16.

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