Bryce Canyon National Park: The Desert's Hoodoo Heart by Park Partners Inc.

"The geology of Bryce is as surprising as it is beautiful. Thor's Hammer, the Silent City, Wall Street, Natural Bridge— each arose from the hands of the same relentless sculptor: small amounts of water falling over vast amounts of time. It is ironic, in this bone-drying desert where yearly precipitation averages a mere 16 inches, that water is responsible for shaping most of what we see. The geological formula at Bryce is basic; the details, fascinating."