In Europe and North America, the Holocene is subdivided into Preboreal, Boreal, Atlantic, Subboreal, and Subatlantic stages of the Blytt–Sernander time scale.
There are many regional subdivisions for the Upper or Late Pleistocene; usually these represent locally recognized cold (glacial) and warm (interglacial) periods.
The last glacial period ends with the cold Younger Dryas substage.
The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy, representing the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period.
[1] While the Gelasian and the Calabrian have officially been defined by the International Union of Geological Sciences (IUGS) to effectively constitute the Early Pleistocene, the succeeding Chibanian and Tarantian ages have yet to be ratified.