Geologic Time: The Paleozoic The Paleozoic era is the earliest and largest part of the Phanerozoic eon, lasting from 541 to 252.2 million years ago. geology.about.com/od/geotime_dating/a/Geolo...
The Paleozoic Era The Paleozoic Era is the beginning of an explosion of life forms. The Cambrian Explosion marks the era with thousands of new life forms in the ancient seas. fossils-facts-and-finds.com/paleozoic_e...