Learn how geologists have used the rock record to determine geological time. Reading rocks includes looking at erosion, when mountains were built, and tectonic shifting. Before looking at the geological divisions themselves, read a brief history of how describing geological time has been refined over the years. Included is a chart which shows the era, period, epoch and when each began and ended. A handy glossary defines some terms used in describing geological time. For more information you can click on related sections of the museum and items related to the geological time scale.
courtesy of Knovation