or palaeontology
Scientific study of life of the geologic past, involving analysis of plant and animal fossils preserved in rocks.
It is concerned with all aspects of the biology of ancient life forms: their shape and structure, evolutionary patterns, taxonomic relationships with each other and with modern species, geographic distribution, and interrelationships with the environment. Paleontology has played a key role in reconstructing the Earth's history and has provided evidence to support the theory of evolution. Data from paleontologic studies have also aided petroleum geologists in locating deposits of oil and natural gas, which are frequently associated with the remains of certain ancient life forms.