Geology

• Gohau, Carozzi and Carozzi in their "History of Geology" describe the facies fossil as being of an animal that was "adapted to life in a restricted environment. It prefers certain ecological surroundings."
  
  

Examples

• Gastropods (like snails) are one type of facies fossil. Snails have existed for millennia, so, are a poor indicator of date. But, they signify an aquatic environment.
  
  

Biofacies

• A sedimentary layer based on its rock characteristics is known as a lithofacies, whereas one known by its fossil content is a biofacies.
  
  

Zone Fossils

• In contrast to facies fossils are zone fossils, restricted to "specific levels within the stratigraphic column." These fossils appear in a certain period of time, versus a certain type of environment.
  
  

Range

• A range is the time interval during which a species existed on Earth. A facies fossil is less dependent upon range than a zone fossil. A trilobite is a zone fossil, the fossil of a marine arthropod that lived within a range of about 540 million years ago up until 250 million years ago.