A traveler entering the state of Washington from the east crosses a flat-to-rolling countryside of deep, fertile soil commonly sown with wheat. Then, abruptly, the landscape shifts to one of bare black rock cut by labyrinthine canyons and channels, plunge pools, and rock basins. The rugged terrain features cascade and cataract ledges, ragged buttes and cliffs, immense gravel bars, and giant ripple marks--the geologic legacy of the so-called Spokane Flood. Weis's concise but informative guide summarizes the sequence of ice-age events that culminated in the flood.