range zone Unit of strata defined by the presence and time range of a particular fossil taxon. A range zone comprises the entire vertical and horizontal extent of the given organism. Range zones may be local (teilzone, or local range zone), or the term may be used to refer to the total stratigraphic range of a particular taxon (taxon range zone). When used formally (see FORMAL) the term is capitalized and the qualifying fossil name given in italics, with the generic name capitalized and the specific name in lower-case letters, e.g. the stratigraphic range of the Late Jurassic ammonite Cardioceras cordatum delimits the Cardioceras cordatum Range zone.

range zone A unit of strata that is defined by the presence and time range of a particular fossil taxon. A range zone comprises the entire vertical and horizontal extent of the given organism. When used formally, the term is capitalized and the qualifying fossil name given in italics, with the generic name capitalized and the specific name in lower-case letters (e.g. the stratigraphic range of the Late Jurassic ammonite Cardioceras cordatum delimits the Cardioceras cordatum Range zone.