geological era
Younger Dryas
return to glacial conditions after the last glacial maximum, which temporarily reversed the gradual climatic warming
Gallic epoch
obsolete epoch of the Cretaceous
Aegean
geological period
Caradoc
former geological series overlapping the Sandbian and Katian
Imbrium
Lunar geological period
Nectarian
geologic period, 3920 to 3850 million years ago
Basin Groups
9 subdivisions of the lunar Pre-Nectarian geologic period