More from this author. 1  Largest World Cities: 2014. 2  World Urban Areas Population and Density: A 2012 Update. 3  Largest Cities in the World: 2016. 4  Largest 1,000 Cities on Earth: World Urban Areas: 2015 Edition. 5  The Costs of Smart Growth Revisited: A 40 Year Perspective.
Definition of fossil. 1  1 : a remnant, impression, or trace of an organism of past geologic ages that has been preserved in the earth's crust â compare living fossil. 2  2a : a person whose views are outmoded : fogyb : something (such as a theory) that has become rigidly fixed.
Fossils are evidence of ancient life forms or ancient habitats which have been preserved by natural processes.They can be the actual remains of a once living thing, such as bones or seeds, or even traces of past events such as dinosaur footprints, or the ripple marks on a prehistoric shore.ossil types. Body fossils are the preserved remains of the actual body parts of an animal or plant such as a skeleton or a pollen grain. Trace fossils are the remains of ancient activity, such as the burrow left by a worm or a stone tool made by a prehistoric person.