Fossils Tell of Long Ago (Let’s-Read-and-Find-Out Science 2)

What is a fossil?Sometimes it's the imprint of an ancient leaf in a rock. Sometimes it's a woolly mammoth, frozen for thousands of years in the icy ground. Sometimes it's the skeleton of a stegosaurus that has turned to stone.A fossil is anything that has been preserved, one way or another, that tells about life on Earth. But you can More »