Fossils
Fossils are the imprints, casts, or remains of organisms that lived more than 10,000 years ago. Fossils may be the actual bones of animals or the impression left by plant fronds in soft mud millions of years ago. Fossils are usually found in sedimentary rock. The plant or animal was covered by sediments that hardened into rock trapping its remains as a fossil. Some fossils are also recovered from tar pits and amber. Both are excellent preservatives. Areas of turbulence such as the ocean shoreline and a rapidly flowing stream are not places that fossils would likely form. Decay and scavenging can also affect chances for fossil formation.
