Thus, one way or another, many rock units formed during the last couple of billion years have performed on the stage of the Colorado Plateau and, hamlike, still lurk in the wings eagerly awaiting your applause to recall them to the footlights. Don’t let them down—visit and enjoy the national parks and monuments of the Plateau, for they probably are the greatest collection of scenic wonderlands in the world. Additional Reading Many reports covering various aspects of the area have been cited in the text by author and year, and these plus a few additional ones are listed in “Selected References.” A few works of general or special interest should be mentioned, however. Between 1926 and 1929 the entire area now included in the park was mapped geologically in classic reports by Dane (1935) and by McKnight (1940). These men and their field assistants mapped the area by use of the plane-table and telescopic alidade without benefit of modern topographic maps or aerial photographs, except for topographic maps of the narrow stretch along the Colorado River mapped under the direction of Herron (1917). Only small sections could be reached by automobile, so nearly all the area was traversed using horses and mules or by hiking. This work plus mapping done in nearby areas to the south and to the north (Stokes, 1952) during the uranium boom of the mid-fifties was used by Williams (1964) in compiling a geologic map of the Moab quadrangle at a scale of 1:250,000. Several early reports on the Colorado River and its potential utilization contain a wealth of information and many fine photographs, including two by La Rue (1916, 1925) and one by Follansbee (1929). You may be interested in brief accounts of the geology of other national parks and monuments, or other areas of special interest, such as the reports on the Uinta Mountains by Hansen (1969), Mount Rainier by Crandell (1969), Yellowstone National Park by Keefer (1971), and ones by me on Colorado National Monument (Lohman, 1965) and Canyonlands National Park (1974). For those who wish to learn more about the science of geology, I suggest the textbook by Gilluly, Waters, and Woodford (1968). Acknowledgments I am greatly indebted to Bates Wilson, former Superintendent, and to former Assistant Superintendent Joe Carithers, for their splendid cooperation in supplying data and information; to Chuck Budge, former Chief Ranger; Dave May, Assistant Chief of Interpretation and Resource Management; Joe Miller, former Maintenance Engineer; Bob Kerr, new Superintendent; Maxine Newell, Park Historian and member of the staff at Arches National Park; Jerry Banta, former Park Ranger at Arches; and Carl Mikesell, Park Ranger at Arches, for their many favors.