Book 24, Question 18
Why can you see stripes in a road cut or riverbank?
The stripes are layers of sediment that built up in different periods. Each layer is made of different materials, such as sand, clay, or pebbles, and the colors reflect the minerals in them. Usually the oldest layers are at the bottom and the youngest at the top, unless the ground has been folded or tilted. Layers are like pages in the book of the ground.