Paleontology is the scientific study of pre-­existing life based on fossils.

Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. These may include an actual part of the animal, such as bones, teeth, or shells. Or, the organic material may be replaced by minerals such as silica, iron and manganese, as in petrified wood.

Fossils may also include a track or a trail, an imprint or a cast, anything that indicates pre-existing life forms.

Paleontology lies on the border between biology and geology.