A stratotype (type section) comprising more than one designated standard section of strata. Such a designation may be made: (a) if an entire lithostratigraphic unit is not completely exposed as a discrete section at any one locality, in which case only one section can be the holostratotype, the other or others being subsidiary parastratotypes; or (b) in the case of chronostratigraphic units, when those of higher rank (e.g. systems) may be composite-stratotypes of constituent lower-rank stratotypes, (e.g. series).