The IUGS Executive Committee has voted unanimously to ratify the proposal for formal adoption of the chronostratigraphical/geochronological unit divisions subseries/subepoch within the International Stratigraphic Guide as approved by the International Commission on Stratigraphy and forward to the IUGS EC on 24 March 2021**. The subseries/subepochs are now incorporated in a six-tiered chronostratigraphic hierarchy of units that are formally defined by a designated GSSP (Global Stage Stratotype and Point) at the base of designated type stages. Henceforth, subseries/subepochs of the Cenozoic are to be denominated by capitalised positional adjectives -- Lower/Early, Middle, and Upper/Late – added to the names of the relevant series/epochs.