Driving across I-70 in southern Utah one can't help but wonder about the magnificent upturned rocks of the San Rafael Reef. With A Travelers Guide to the Geology of the Colorado Plateau in hand, you'll soon discover that you were driving through Page and Navajo Sandstone formations, sharply folded into a monocline along one of the "Basin and Range" fault lines. Nearing Flagstaff, Arizona, on Highway 89, you will learn that Mt. Humphry of the San Francisco...