Prehistoric time line, geologic time scale, photos, facts, maps ... that time. Earth formed and oxygen levels rose in the foundational years of the Precambrian. The productive Paleozoic era ...

Generalized geologic map of Nova Scotia. Avalon and Meguma Terranes are juxtaposed ... zones which range in age from Late Precambrian through the Early Paleozoic (figure 3). Four of these can be ...