Sedimentary rocks are formed when rocky fragments and sediments are deposited together by wind, water or ice. Over time they cement together into new rocks. Limestone and sandstone are common sedimentary rocks. You can often find fossils embedded in these rocks—they were deposited together with the sediments!

Some rocks are dramatically changed by forces inside the Earth. Extreme heat or pressure underground can bake, squeeze, or fold rocks into something new. Then they are called metamorphic rocks—metamorphic is Greek for "change of form." Marble, for example, is metamorphized limestone.

Back to The Mystery of the Floating Rock

© The Children's Museum of Indianapolis, 2000