36″ x 24″ full color laminated poster. The geological time scale divides the history of the Earth into units of time based on layers of rock (strata). Paleontologists use this scale to establish dates when various species lived. This chart is essential to the study of both earth and life science. At the top, an introduction explains the geological time scale, its significance, how it was created, and index fossils. The main design consists of strips of illustrations, each presenting a period of geological time. The emphasis is on the last 360 million years when advanced life inhabited the earth. Each geological period is introduced by informative text explaining the origin of its name and its significance. It is followed by magnificent illustrations showing life on land and in the seas, index fossils, and a globe showing the position of the continents. The most important groups of animals and plants are introduced in the margins through images and captions. They complement the period illustrations that show how the species within the groups changed over millions of years.