City of Mesa, AZ

Dinosaur Mountain - Jurassic Arizona

The second level from the bottom of the mountain represents the plants and animals of the Jurassic Period Morrison Formation, about 155 million years ago. Many of the best-known dinosaurs lived in the Jurassic, when sauropods, the long-necked dinosaurs, dominated the landscape. The Morrison Formation has been the site of many finds in Utah, Colorado and New Mexico, but so far few dinosaurs have been found in the Morrison Formation in Arizona.

photo of Stegosaurus on dino mountain

Stegosaurus

photo of Stegosaurus replica

At over 20 feet long and weighing up to two tons (4,000 pounds), this was the largest member of the stegosaur group. The plates on the back may have had a defensive function, as scientists have long supposed, but the excellent circulation system in the plates suggests they may have been for temperature control, acting as radiators and solar collectors.

Fruitachampsa

photo of Fruitachampsa replica

This small crocodilian was a swift upland predator, apparently dominating the small predator niche in the early Morrison Formation. At several times and places, some crocodilians have left their traditional aquatic life and pursued a more terrestrial strategy.

Echinodon & Termite Nest

photo of Echinodon and termite nest replica

The small, plant-eating dinosaur, Echinodon, reached only about 24 inches in length and is one of the smallest dinosaurs known. Fossils of Echinodon have been found in Colorado, England and Portugal.

Recent discoveries in New Mexico show that termite nests appeared in the Morrison Formation. Some of these nests were over 100 feet tall. Termites build their nests by bonding sand grains together with their saliva, feces and partly digested wood material.

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