Dinosaur National Monument
Dinosaur National Monument is a U.S. National Monument located on the southeast flank of the Uinta Mountains on the border between the American states of Colorado and Utah at the confluence of the Green and Yampa Rivers. Although most of the monument acerage is in Colorado, the Dinosaur Quarry is located in Utah just to the north of the town of Jensen, Utah. The Dinosaur wall located within the Dinosaur Quarry building in the park consists of a steeply tilted (67° from the horizontal) rock layer which contains hundreds of dinosaur fossils. The enclosing rock has been chipped away to reveal the fossil bones intact for public viewing. The nearest communities are Vernal, Utah and Dinosaur, Colorado.
The rock layer enclosing the fossils is a sandstone and conglomerate bed of alluvial or river bed origin known as the Morrison Formation from the Jurassic Period some 150 million years old. The dinosaurs and other ancient animals were washed into the area and buried presumably during flooding events. The pile of sediments were later buried and lithified into solid rock. The rock layers were later uplifted and tilted to their presnt angle by the mountain building forces theat formed the Uintas. The relentless forces of erosion exposed the layers at the surface to be found by paleontologists.
The dinosaur fossil beds were discovered in 1909 by Earl Douglass, a paleontologist working and collecting for the Carnegie Museum. He excavated thousands of fossils and shipped them back to the museum in Pittsburgh, Pennsylvania for study and display. President Woodrow Wilson proclaimed the dinosaur beds as Dinosaur National Monument in 1915.