[Illustration: Department of the Interior · March 3, 1849] UNITED STATES DEPARTMENT OF THE INTERIOR Fred A. Seaton, _Secretary_ NATIONAL PARK SERVICE Conrad L. Wirth, _Director_ For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. Price 25 cents THE DINOSAUR QUARRY DINOSAUR NATIONAL MONUMENT _Colorado_ · _Utah_ _By John M. Good, Theodore E. White and Gilbert F. Stucker_ [Illustration: Apatosaur in Swamp] NATIONAL PARK SERVICE · Washington, D. C., 1958 _The National Park System, of which Dinosaur National Monument is a unit, is dedicated to conserving the scenic, scientific, and historic heritage of the United States for the benefit and enjoyment of its people._ [Illustration: National Park Service · Department of the Interior] Contents _Page_ THE QUARRY 2 THE DINOSAURS 3 First Discoveries 3 Position of Dinosaurs Among Reptiles 4 Geologic History 4 What They Looked Like 6 Temperature Tolerance 10 Gizzard Stones 11 THE CLIMATE, LIFE, AND LANDSCAPE OF JURASSIC TIME 12 How Do We Know? 14 ANIMALS FROM THE QUARRY 15 Why So Many? 19 How Were They Preserved? 21 How Were They Exposed? 24 WHY DID DINOSAURS BECOME EXTINCT? 25 HISTORY AND DEVELOPMENT OF THE QUARRY 26 Discovery and Early Years 26 Starting the Quarry 28 Extent and Development of the Find 28 Work Methods 32 Further Development 34 Protecting the Quarry 35 Present Development 37 THE SCENE TODAY 38