How do biozones scientists identify rock layers across distances?

A biozone is a portion of a layer of Earth’s crust where fossils are found. Biozones help scientists to excavate the fossils and help trace the path of evolution over time as it is a stratigraphic unit which is defined by its fossil content. There are several different ways in which biozones can be designated in terms of the zone fossils that they contain and often, some environmental factors that take place to consider the definition and interpretation of biozones.