Book excerpt: Learn about the remarkable geologic diversity of the Gem State with the completely revised, full-color edition of Roadside Geology of Idaho. Excellent graphics, spectacular photographs, and straightforward writing describe and interpret the rocks and landscapes visible outside your car window, whether you're speeding across the Snake River Plain or following a narrow canyon enroute to a weekend getaway. The authors, a trio of experienced field geologists, guide you to outcrops and roadcuts where you can stretch your legs and expand your minds. The rocks of Idaho span a vast chunk of Earth's long-lived history and tell stories with many plot twists. Time and time again, geologic processes transformed the landscape-- mountains grew to towering heights only to be leveled by erosion, vast lakes drained in massive floods when ice and sediment dams failed, and lava poured into river valleys, creating new dams. With this book as their travel companion, residents and visitors alike are sure to understand and appreciate Idaho's sprawling plains, forested hills, and deep canyons in a completely new way.