Age of Mammals: darwin.bio.uci.edu/~sustain/bio65/lec02/b65lec02.htm All about dinosaurs: www.EnchantedLearning.com/subjects/dinosaurs/ Fossils Index: pubs.usgs.gov/gip/geotime/fossils.html Life through Geologic Time: seaborg.nmu.edu/earth/Life.html