Archean Archean eon Archean aeon Archeozoic Archaeozoic Archeozoic eon Archaeozoic aeon
archean%1:28:00:: archean_eon%1:28:00:: archean_aeon%1:28:00:: archeozoic%1:28:00:: archaeozoic%1:28:00:: archeozoic_eon%1:28:00:: archaeozoic_aeon%1:28:00::
Arhaik
the time from 3,800 million years to 2,500 million years ago; earth's crust formed; unicellular organisms are earliest forms of life