Geologic Time
GeoWhen Database, with Stages
From The International Commission on Stratigraphy (ICS). The GeoWhen project aims to reconcile the international stratigraphic standards with many of the regional and archaic naming schemes that appear in the literature.
Geologic Time Pie
From Levin (1999)
Precambrian time divisions
From Levin (1999)
Detailed DNAG timescale
From Geologic Society of America
Interactive Timescale #1
From EnchantedLearning.com
Interactive Timescale #2
From UC-Berkeley