Crrr-ack!A boulder falls from a mountain and cracks into cobbles, which transform into pebbles, then granules, then sand, and silt. What began as a mountain in the clouds forms a mountain in the ocean… and the cycle begins again. Extra nonfiction content at the back of the book gives readers a more in-depth look at how scientists classify different rock sizes. A gorgeous introduction to the rock cycle for the youngest geologists.