Fossils Study Guide Fossils Schimmel Fossils Fossils are the preserved remains of a plant or animal that lived long ago. Types of Fossils Bones teeth shells imprints How a fossil is formed A paleontologist is a scientist that studies fossils.

Kinds of Fossils Mold When an organism dies in mud, the mud fills the spaces around the organism. When the organism breaks down a hollow space is left in the mud. Cast A cast forms when sand or mud fills the spaces of a mold. Amber When organisms become trapped in tree sap, the tree sap hardens. The hardened tree sap is called amber. Petrified Wood When a tree dies and becomes covered with mud, the minerals seep into the wood and harden. When they harden, they take the shape of wood. The trees “turn to rock” or become petrified.