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Dinosaur National Monument
In 1909, Earl Douglass, a staff paleontologist with the Carnegie Museum in Pittsburgh, Pa., spotted eight fossilized tail bones exposed on top of a ridge on the arid landscape near Vernal.
It was a major discovery. For 15 years, he supervised removal of fossils, most of which were shipped to the Carnegie Museum to be displayed.
The site of Douglass' excavations is now the quarry at Dinosaur National Monument, established in 1950. More than 1,600 fossils are exposed on the quarry wall today.
Excavation at Dinosaur National Monument, 20 miles by highway to the east of Vernal, has unearthed enough bones and other remains that scientists can reconstruct a detailed picture of what life was like there during the late Jurassic era.
Fossils of 13 different kinds of animals have been excavated from the cliff face near the visitors center since digging began in 1909. Most are dinosaurs, but there are also some crocodilians, turtles and lizard-like animals.
The tilted bed of sandstone you see when you enter the quarry was once a sandbar in a river. About 150 million years ago, during the Jurassic Period, the river covered bones of dinosaurs with sand and gravel. Several thousand feet of mud and sand from inland seas then covered the region, compressing and solidifying the river deposits.
About 65 million years ago the Earth's crust buckled, tilting the sandstone river bed upward. Erosion exposed the sandbar and some of its fossilized contents.
Scientists no longer chip away at the famous quarry, which is enclosed by the visitors center. Instead, expeditions now search the backcountry, away from the quarry.
In the national monument's more remote areas, around 35 additional species were discovered recently, including salamanders and some of the earliest frogs ever found. Separate kinds of plants can be tallied through studies of pollen traces in the formations.
More information is available at www.nps.gov/dino/
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