KEY TO PRONUNCIATION 46 SUGGESTED READINGS 47 [Illustration: JURASSIC LANDSCAPE SHOWING ANIMALS AND PLANTS THAT LIVED HERE DURING MORRISON TIME. (FROM A PAINTING BY ERNEST UNTERMAN.)] [Illustration: Spade and Pick] As you approach Dinosaur National Monument from Jensen, Utah, you see the mass of Split Mountain and the deep, short canyons that scar its south slope near the Green River’s gorge. As you cross the National Monument boundary the grand view is lost and you begin to notice details. The masses of gray shale that seem to be carelessly piled against the tilted sandstone layers are bare of vegetation. The ground between the hills and the Green River is covered with sagebrush and greasewood, while along the river itself are a few large cottonwood trees and many bushes. A sharp turn brings a change of scene as your car enters a portal in the wall you have been following. The pronounced tilt of the rocks becomes more obvious. A final steep climb and the visitor center is at hand. This building encloses a significant part of the Dinosaur Quarry, perhaps the greatest deposit of fossil dinosaur bones known today. From this quarry have come many of the dinosaur skeletons that are seen today in our great museums. After parking, a short walk to the overlook on the southeast reveals a splendid view of Split Mountain. Between that broad arch of eroded sandstone and the quarry lie steeply tilted sedimentary rocks of various compositions and hues. Buff and gray sandstones that weather into soft shapes are separated by reddish-brown shale. Directly to the east is a section of varicolored shale whose pastel pinks, reds, greens, grays, and whites justify the name of “rainbow beds” that was given them by geologists. In the upper part of this section are hard sandstone and limestone layers that resist the erosive action of wind and water. They stand higher than the softer shales and form hogbacks that rim Split Mountain. One of these layers can be traced across the ravine immediately east of the parking area into the sandstone ledge that forms the north wall of the visitor center. This is the famous Dinosaur Ledge. The Quarry The Dinosaur Ledge is famous because here the world’s greatest store of fossil bones of these long extinct reptiles has been uncovered. Two groups, or orders, of dinosaurs have been discovered, with a number of different types or kinds somewhat related to each other within these orders. From the fossil bones, scientists can tell that these creatures varied greatly in size and habits of living. [Illustration: TILTED ROCK STRATA NEAR THE DINOSAUR QUARRY.]