Fossils are evidence of past life. They are formed in many ways. After a plant or animal dies, its soft tissues usually decay or are eaten. Most fossils are formed when the hard parts are protected from decay by natural burial soon after the organism dies. For this reason, most fossils are found in sediments that were laid down by water - either ancient rivers, lakes, or oceans.

imprint of leaf	imprint of plant
small clam	therapod track
ammonite fossil	a claw
trilobite	hadrosaur leg bone
crocodile jaw	wasp in amber
giant mammoth (found in ice frozen for 10,000 years)	mammoth hair
tar pits	First the bones were saturated with asphalt, which stopped decay. Preservation of the fossils took place after the saturated bones had been buried beneath water-borne sediment. Unlike most fossils, the fossils from Rancho La Brea are unchanged, original material.
shark teeth
coprolite	Links to great fossil pictures and information: http://www.ammonite.ws/ http://www.envs.emory.edu/ichnology/dinotraces.html http://www.coloradomtn.edu/campus_rfl/staff_rfl/kohls/eocene.html http://tabla.geo.ucalgary.ca/~macrae/Burgess_Shale/ http://www.museum.vic.gov.au/dinosaurs/ http://www.uky.edu/KGS/coal/webfossl/pages/devonian.htm Project Prosaurapod Fossils of New Jersey