Old Earth Ministries Online Earth History Curriculum

Presented by Old Earth Ministries (We Believe in an Old Earth...and God!)

This curriculum is presented free of charge for use by homeschooling families.

NOTE:  If you found this page through a search engine, please visit the intro page first.


Chapter 1 - Earth History Overview

Lesson 3: Geologic Time Scale Divisions


     The geologic time scale is a living document, with changes being considered each year.  You will need to memorize part of the scale in order to better understand earth's history.

   The table of geologic time spans presented below agrees with the dates and nomenclature proposed by the International Commission on Stratigraphy, and uses the standard color codes of the United States Geological Survey.  The time scale below is compressed, with the geologic division of "Ages" removed.   

Chapter 1 - Overview


Lesson 1: The Age of the Earth

Lesson 2: Geologic Time Scale

Lesson 3: Time Scale Divisions

Lesson 4: Geology Basics Review

Lesson 5: Plate Tectonics

Lesson 6: Fossils

Lesson 7: Trace Fossils


   The start times are in millions of years.  For example, the Hadean Eon started 4570 million years ago, or 4.57 billion years ago.  The start times have been rounded, with uncertainties removed.  For example, the Cambrian started at 542.0 million years ago,  1 million years.  The   variance is not noted in the chart.

    The most important section that you will definitely have to know by heart is the Eras and Periods of the Phanerazoic Era.  You do not have to memorize the whole chart for this course.



The Geological Society of America publishes a wall chart of the Geologic Time Scale.  It would be very useful to anyone studying the earth's history.  Click here to view and purchase the chart.  Chart is 18" by 27".  Cost is $9.95.

Geologic Time Scale


This can also be printed on a single page sheet from the GSA website


     For reference during the study of this course, we highly recommend that you print out the Geologic Time Scale published by the Geological Society of America (GSA).  It can be found here


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