What is a fossil?

A fossil is any evidence of ancient life that is preserved in stone or other material. Fossils can include molds, casts, defecation material, stomach stones, bones, footprints, trails and burrows. Fossils can be preserved in sedimentary rock (and rarely metamorphic and igneous rock), tar pits, and amber, and are usually the result of the organism being covered rapidly upon death. Fossils are very important in helping us trace the history of life on Earth and the evolutionary relationships between organisms of the past and present.