[Illustration: Geology of Colorado National Monument] [Illustration: BALANCED ROCK, near head of Fruita Canyon. Spire and rock are Wingate Sandstone resting on red Chinle Formation; thin caprock is protective layer of resistant Kayenta Formation. (Frontispiece)] [Illustration: The Geologic Story of COLORADO NATIONAL MONUMENT] _The Geologic Story of_ COLORADO NATIONAL MONUMENT By S. W. Lohman GEOLOGICAL SURVEY BULLETIN 1508 UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, _Secretary_ GEOLOGICAL SURVEY Doyle G. Frederick, _Acting Director_ [Illustration: U.S. DEPARTMENT OF THE INTERIOR · MARCH 3, 1849] Library of Congress Cataloging in Publication Data Lohman, Stanley William, 1907- The geologic story of Colorado National Monument. (Geological Survey Bulletin 1508) Bibliography: p. 131 Includes index. 1. Geology—Colorado National Monument. 2. Colorado National Monument. I. Title. II. Series: United States Geological Survey Bulletin 1508 QE75.B9 no. 1508 [QE92.C6] 557.3s [557.88′17] 80-607952 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Contents Page Preface XI History of the Monument 1 Early history of the region 5 Prehistoric people 5 Late arrivals 10 Early settlement 10 The Brown-Stanton river expedition 11 Kodel’s gold mine 12 Recent cave dweller 13 Artesian wells 14 Geographic setting 16 The geologic story begins 17 Ancient rocks and events 24 A great gap in the rock record 26 The age of reptiles 27 Early landscape 28 Ancient sand dunes 29 The rains came 32 Another gap in the rock record 35