Moving ever upward in the spiral, we come to the Cretaceous—the age of the starring Mesaverde Group, in which the caves of Mesaverde N.P. were formed, and which now house beautifully preserved ruins once occupied by the Anasazi (the ancient people who once dwelt in many parts of the Plateau).
This brings us up to the Tertiary Period, during the early part of which the pink limestones and shales of the Paleocene and Eocene Wasatch Formation were laid down in inland basins. Beautifully sculptured cliffs, pinnacles, and caves of the Wasatch star in Bryce Canyon N.P. and in nearby Cedar Breaks N.M. This concludes our climb up the time spiral, except for Quaternary volcanos and some older volcanic features at Sunset Crater N.M., near Flagstaff, Ariz.
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. Do not 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.
Acknowledgments
I am grateful to many friends and colleagues not only for help on the present report, but also for help on the two preceding reports which made this one possible. I refer to my Professional Paper 451,[43] which supplied the detailed geologic data and to the first popular-style booklet.[44] First of all, I must acknowledge the great help rendered by members of my family—my eldest son Bill for serving as my unpaid field assistant for most of the detailed mapping of the Grand Junction area, and my two younger sons Terry and Bob for similar services during the last phases of the fieldwork. I am especially indebted to my wife Ruth for material assistance in all the fieldwork, including the road logging and the color photography for the present report.
I am grateful to several colleagues of the Geological Survey and National Park Service for help, data, or reviews of all three reports noted, and to members of my family for reviewing both popular-style reports.
For reviewing the present report I am especially indebted to David V. Harris, Emeritus Professor of Geology, Colorado State University; Harry A. Tourtelot, Geologist, U.S. Geological Survey, for reviewing both popular-style reports and contributing petrographic studies to the detailed report; and to my wife, Ruth.
The comments and criticisms of all reviewers were carefully considered and most were adopted, but in some places I have preferred to state things in my own way, and have included topics that seemingly were of more interest to me than to some of the reviewers. The responsibility for the form and content of this report thus remains mine.