In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition.
Stages are divided into smaller stratigraphic units called chronozones or substages, and added together into superstages.
[2] The term faunal stage is sometimes used, referring to the fact that the same fauna (animals) are found throughout the layer (by definition).
As of 2008, the ICS is nearly finished with a task begun in 1974, subdividing the Phanerozoic eonothem into internationally accepted stages using two types of benchmark.
For older stages, a Global Standard Stratigraphic Age (GSSA) is an absolute date.