From 1946 until about 1956 I carried out fieldwork intermittently on the geology and artesian water supply of the Grand Junction area, Colorado, the results of which have been published.[1] The area mapped geologically contains about 332 square miles in the west-central part of Mesa County and includes all of Colorado National Monument. During the fieldwork several successive custodians or superintendents and several park naturalists urged that upon completion of my professional paper I prepare a brief account of the geology of the Monument in terms understandable by laymen, and which could be sold at the Visitor Center. This I was happy to do and there resulted “The geologic story of Colorado National Monument,”[2] published by the Colorado and Black Canyon Natural History Association in cooperation with the National Park Service. This report contained colored sketches by John R. Stacy and a colored cover, but the photographs and many of the drawings were reproduced in black and white. Later, after I had prepared popular style reports containing mostly color photographs on Canyonlands[3] and Arches[4] National Parks, officials of Colorado National Monument and I discussed the possibility of preparing a revised and enlarged edition of my 1965 report containing mainly color photographs, inasmuch as the supply of the black and white edition was nearing exhaustion, and later became out of print. At the meeting in the Monument on June 8, 1976, attended by Robert (Bob) E. Benton, Superintendent, A. J. (Jerry) Banta, Supervising Park Ranger, Margaret Short, Park Naturalist and Secretary of the Natural History Association, and me, it was agreed that: (1) A revised and enlarged edition containing mostly color photographs should be prepared for publication as a bulletin of the U.S. Geological Survey, and (2) that the Colorado and Black Canyon Natural History Association gave its permission for use of any or all of the copyrighted material in the first edition. The present report resulted. The cover is a duotone of a 9- × 12-cm infrared photograph of Independence Monument taken by me. (See also fig. 6.) Most of the color photographs were taken by me on 4- × 5-inch or 9- × 12-cm tripod mounted cameras using lenses of several focal lengths, but I took some with 35-mm cameras. Some of the color photographs and all the black and white ones were taken by those credited in the captions, to whom grateful acknowledgment is made. The points from which most of the photographs were taken are shown in figure 26. [Illustration: West side of Otto’s Monument ROCK OF AGES CROSS OF AGES] History of the Monument