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 How well do you know the geologic time scale? 

The Geologic Time Scale: A Quiz

1) Select the time scale you want to test yourself on:
What is the source for the dates on the time scale that you are trying to memorize?
Harland et al, 1990     DNAG - 1983     USGS 1999     This website

2) Fill in the time scale in the table below:

Begin with the present and work backwards. List more inclusive units first and the units they contain after them. More Instructions and examples

Name of unit: Rank: Time unit began(ma): Time unit ended (ma): Extinction at end killed off

3) Press the submit button to see how well you know the geologic time scale.

See also: The Geologic Time Scale and Metaphors for geologic time.

Time Scale Instructions

List the units of the geologic time scale from most recent to oldest. Indicate whether each unit is an eon, era, epoch, or period. Provide a start and end time for each unit. If a unit ends with an extinction event listed in the pull down menu, select that event. Since larger and smaller units can end at the same time, each extinction event may be listed more than once. Some sources contain more units than others, so you may not need to fill all the rows in the table. Put larger (more inclusive) units first, then list the smaller units that go within them.

Example of smaller units nested in more inclusive units:

Sources: Assembled from various sources. The overall framework is from:Harland et al., 1990; Palmer, 1983. A number of dates and events are from a variety of more recent (1990s) sources.
Part of the Athro, Limited web site.
Copyright © 2000 Athro, Limited. All Rights Reserved.
Written by Paul J. Morris
Maintained by Athro Limited
Date Created: 2000 July 16
Last Updated: 2000 August 12