Booklet giving general explanations of geologic time, major divisions of geologic time, relative and radiometric time scales, index fossils, and the age of the earth.
Homepage linking to National Cooperative Geologic Mapping Program (NCGMP) components: FEDMAP for federal mapping projects, STATEMAP for state geological survey projects, and EDMAP for geologic mapping education projects.
Links to volcanism, volcanic history, volcanic rocks, and general geology by state, by region, national parks and national monuments and a brief introduction to volcanism around the U.S. entitled: Windows into the past.