Websites on the Eons and Eras Phanerozoic Era: http://www.palaeos.com/Timescale/Phanerozoic.htm Mesozoic Time: http://www.palaeos.com/Mesozoic/Mesozoic.htm Paleozoic Era: http://www.palaeos.com/Paleozoic/Paleozoic.htm Precambrian Time: http://www.palaeos.com/Timescale/Precambrian.htm#history Map of the different eras and periods: http://earth.geol.ksu.edu/sgao/g100/plots/1017_timeline.jpg