Fourth Grade
Worksheets
Fossils
Did you ever make a handprint in clay when you were young? Fossils are like those handprints in clay. They preserve memories of the past. Fossils are the preserved evidence or remains of a living thing from long ago. They are formed when plants or animals are buried in sediments. We mostly think of fossils as imprints of a plant or animal in a rock. But fossils can be other things, too. The bones of an animal can become fossils. Worm trails and footprints that have been preserved in rocks are also considered fossils.
Fossils such as worm trails and footprints are called trace fossils. They are not formed from the remains of an organism. They are simply evidence that it once existed. Scientists study these fossils to get a clue about how these organisms lived.
Two types of fossils can be formed when an animal or plant is buried in sediments. One is called a mold and the other is a cast.
