Dinosaur National Monument, Utah & Colorado

Dinosaur National Monument, on the border of Utah and Colorado, is home to one of the greatest dinosaur quarries ever discovered. It is perhaps the world's finest display of fossils in-place available to the public.

The monument also protects many miles of gorgeous canyon country. The confluence of the Green and Yampa Rivers, known as Echo Park, is one of the west's most beautiful places. Huge environmental battles were fought in the past to preserve this area - the Yampa River is the only remaining free-flowing river in the Colorado River system. Photo, above: a scenic stretch of the Green River near the Dinosaur Quarry. Photo, left: Echo Park (courtesy, National Park Service).

The quarry was originally discovered in 1909 by paleontologist Earl Douglass of the Carnegie Museum in Pittsburgh. He worked the find for many years, sending spectacular specimens back to the museum, which included many nearly intact (articulated) skeletons. Many of the fossils were from the giant sauropods of the Jurassic era (about 150 million years ago at this site) of dinosaurs such as Apatosaurus (formerly Brontosaurus). Eventually, the National Park Service took over the quarry and redeveloped it for public display. A field house / visitor center was built over the open hilltop quarry, and about 1,500 bones were exposed in place. Photo, right: The Dinosaur Quarry and Visitor Center. Photo, above left: the vista from the quarry.

The site is at the top of a small but steep hill in an area of colorful badlands. The present exposed area is about 100 meters long and 20 meters high on a steep wall (photo, left). The original excavators dug away much of the original hilltop in their quest for the bones. The photo, right, is a closeup of the left end of the wall. The sharpness of the shot has been exagerated so the imbedded bones are clearly visible. Note the gigantic sauropod leg bones in the far right of the shot.

The site is rich in sand and gravel indicating that the dinosaur carcasses were trapped at the bottom of an ancient river. The large number of bones probably collected during periods of flooding and were then covered quickly by sand and gravel. Perhaps a sand bar or bend in the river caused so many bones to collect in one place.

The ancient environment was semiarid but warm year round. The area was a vast plain with rivers flowing in shallow valleys from a high mountain range to the west. The riparian areas around the river beds provided excellent habitat for large animals.

How did a river bottom end up at the top of a steep hill? The river bed was buried under many layers of debris over the eons. However local geologic forces bent many layers upward into nearly vertical positions with the appearance of a steep hill. More eons of erosion wore off the top of the hill, eventually exposing the edge of the fossil layer. Vertical rock layers can clearly be seen in the photo at the top of this article (on the far side of the river).

(At left, a happy stegosaurus in the gardens at the Utah Field House of Natural History in nearby Vernal, Utah. The museum is an example of the numerous first-rate small town museums in Utah and is definitely worth a visit.)

The two-tiered gallery provides excellent viewing of the wall. The park service offers brochures which describe all of the exposed bones. The rear of the gallery has various exhibits including casts of some of the most spectacular finds ever taken from the quarry, including the most complete sauropod skeleton ever found and the largest allosaurus skull ever found. Photo, right: a nice closeup of a huge leg bone; at left, a human comparison from the Utah Field House. Note the bone to the right and above the person.

Below left, an intact skull and neck of a small sauropod. Intact skulls are extremely rare in the world of dinosaur fossils. The bones of the skull were very light and fragile compared to their generally huge leg and torso bones, so they tended to fall apart quickly after decomposing. At right, an articulated skeleton recently found nearby. It was thought to be a newly discovered species of theropod (meat eater). Note how the entire matrix (work area) was carved out of the ground then wrapped in plaster to be moved. The top of the plaster was removed so the find could be temporarily displayed in the field house.