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 area is in Moffat County, Colorado, the Dinosaur Quarry is located in Utah just to the north of the town of Jensen, Utah. The nearest communities are Vernal, Utah and Dinosaur, Colorado. This park has fossils of dinosaurs including Allosaurus and various long-neck, long-tail sauropods.


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 present angle by the mountain building forces that formed the Uintas. The relentless forces of erosion exposed the layers at the surface to be found by paleontologists.


The dinosaur fossil beds (bone beds) were discovered in 1909 by Earl Douglass, a paleontologist working and collecting for the Carnegie Museum. He and his crews 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. The monument boundaries were expanded in 1938 from the original 80 acre tract surrounding the dinosaur quarry in Utah, to its present extent of over 200,000 acres (800 km²) in Utah and Colorado, encompassing the spectacular river canyons of the Green and Yampa.

Though lesser-known than the fossil beds, the petroglyphs in Dinosaur National Monument are another treasure the monument holds. Due to problems with vandals, many of the sites are not listed on area maps.

The Quarry

The Dinosaur wall located within the Dinosaur Quarry building in the park consists of a steeply tilted (67° from 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. In July 2006, the Quarry Visitor Center was closed indefinitely due to structural problems that have plagued the building since 1957 as it was built on unstable clay. The current preferred plan is to rehabilitate the existing Quarry building, destroying the serpentine ramp, administrative, and museum facilities. A new facility to house the visitor center and administrative functions would be constructed elsewhere in the monument. This plan would provide a safe structure while still retaining a portion of the historic Mission 66 era exhibit hall.

Vertebrate Fossils from Carnegie Quarry

Now enclosed by the Dinosaur Quarry building (Gilmore (1936), Foster (2003))
(h) = holotypeReptilia
Glyptops plicatus
Dinochelys whitei
Opisthias rarus
Goniopholis sp.
Hoplosuchus kayi (h)Dinosauria
Ceratosaurus sp.
Torvosaurus sp.
Allosaurus fragilis
Apatosaurus louisae (h)
Barosaurus lentus
Camarasaurus lentus
Diplodocus "longus"
?Haplocanthosaurus sp.
Uintasaurus douglassi (h) (now Camarasaurus lentus)
Stegosaurus sp.
Camptosaurus aphanoecetes {h)
Dryosaurus altus

Echo Park Dam controversy

U.S. Bureau of Reclamation plans for a ten-dam, billion dollar Colorado River Storage Project began to arouse opposition in the early 1950s when it was announced that one of the proposed dams would be at Echo Park, in the middle of Dinosaur National Monument. The controversy assumed major proportions, dominating conservation politics for years. David Brower, executive director of the Sierra Club, and Howard Zahniser of The Wilderness Society led an unprecedented nationwide campaign to preserve the free-flowing rivers and scenic canyons of the Green and Yampa Rivers. They argued that, if a national monument was not safe from development, how could any wildland be kept intact?

On the other side of the argument were powerful members of Congress from western states, who were committed to the Colorado River Storage Project in order to secure water rights, obtain cheap hydroelectric power and develop reservoirs as tourist destinations. After much debate, Congress settled on a compromise that eliminated Echo Park Dam and authorized the rest of the project. The Colorado River Storage Project Act became law on April 11, 1956. It stated, “that no dam or reservoir constructed under the authorization of the Act shall be within any National Park or Monument.”

Historians view the Echo Park Dam controversy as signaling the start of an era that includes major conservationist political successes such as the Wilderness Act and the Wild and Scenic Rivers Act.


  • Jon M. Cosco, Echo Park: Struggle for Preservation (Johnson Books, 1995) ISBN 1-55566-140-8
  • John R.Foster, 2003. Paleoecological analysis of the vertebrate fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain region, USA. New Mexico Museum of Natural History and Science 23:1-95
  • Charles W. Gilmore, 1936, Osteology of Apatosaurus, with special references to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11(4): 177-294.
  • Mark W.T. Harvey, A Symbol of Wilderness: Echo Park and the American Conservation Movement (University of Washington Press, 2000) ISBN 0-295-97932-1

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