stratigraphic unit consisting of all the strata containing a particular fossil and, hence, deposited during its existence. The extent of the unit in a particular place, on the local stratigraphic range of the fossil plant or animal involved, is called a teilzone. The geological time units corresponding to biozones and teilzones are biochrons and teilchrons, respectively. Biozone is also used synonymously with the terms zone and range zone in stratigraphy.