Paleontology and Biostratigraphy
Paleontology, or palaeontology, is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised faeces (coprolites), palynomorphs and chemical residues.
Biostratigraphy uses those fossils, tracks, and other finds in an effort to figure out how old a certain layer of rock and sediment is.
Once a petroleum geologists knows how old a particular area is, they know the potential for finding natural resources such as oil or natural gas.
Links
Palaeos: The Trace of Life on Earth
Paleontological Research Association Museum of the Earth
International Palaeontological Association
American Association of Stratigraphic Palynologists
The International Nannoplankton Association
The Palaeontological Association
University of Kansas Paleontological Institute