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.
TILTED ROCK STRATA NEAR THE DINOSAUR QUARRY.
Some were the size of chickens, others as big as horses, and others of such gigantic size that no land animal alive today can compare with them. Some were flesh-eaters as indicated by the size and shape of their teeth and their long sharp claws. Others were plant-eaters and again it is the structure of their teeth and feet that tell us this. The flesh-eaters were two-footed and walked on their hind legs, balancing themselves with heavy long tails. Their short front legs were used as clawed-arms for tearing at the flesh of other dinosaurs. Many plant-eaters, on the contrary, were large, heavy, four-footed beasts, often with long necks and tails. Many of the dinosaurs were land dwellers, and many others lived in the great marshes and swamps of the long Mesozoic (middle life) Era of the earth’s history.
Though the subclass of reptiles we call dinosaurs lived all through the Mesozoic Era, those whose fossil bones have been uncovered in this Dinosaur Quarry are embedded in a stratum of rock called the Morrison formation. This rock stratum dates from the Jurassic Period in the middle of the Mesozoic Era.