4.2.4 System (System)
4.2.4.1 System is the fundamental chronostratigraphical unit. It ranks next below an erathem, and is applicable and valid worldwide. The Phanerozoic systems are the Cambrian (kambrium), Ordovician (ordovicium), Silurian (silur), Devonian (devon), Carboniferous (karbon), Permian (perm), Triassic (trias), Jurassic (jura), Cretaceous (kritt), Tertiary (tertiær) and Quaternary (kvartær). The division of time corresponding to a system is a period (periode).
4.2.4.2 Subsystem (undersystem) and supersystem (oversystem) -- Every system so far approved originated in European geology. Elsewhere in the world, some of these systems have been divided or combined. These new units have also been referred to as systems, but it is better to use subsystem (e.g. the Mississippian Subsystem of the Carboniferous System) or supersystem (e.g. the Karroo Supersystem) in such cases (NACSN 1983).