Mighty mountains reach up high, until craggy cliffs tumble and boulders settle everywhere. But how do big, jagged rocks turn into the soft sand we love at the beach? Step by step, Sally M. Walker's simple, scientifically accurate narration lets the youngest geologists learn how rocks weather over time, transforming from cobbles to pebbles to the tiniest grains of sand. Kim Smith's lush landscapes capture a wide range of fauna over geologic time, from dinosaurs and mammoths to bunnies and gulls. A note to parents suggests bringing the learning to life by encouraging questions and observations of the natural world.