This colorful, 3-D model correlates rock layers to geologic time periods. Constructed of durable vinyl, the 23-1/2"W x 24-1/2"H model features 20 replica fossils which students match to appropriate strata. Models illustrates the aquatic and terrestrial life living in the Pre-Cambrian era through the Cenozoic. In addition to eras, periods and years are also indicated on the chart. Includes Teacher's Guide with activities. Grades 5-12.