The end of the Paleozoic and beginning of the Mesozoic 251 million years ... As they work through the investigation, the group should come to a consensus about where on the time line they are. Each ...

Prehistoric time line, geologic time scale ... rose in the foundational years of the Precambrian. The productive Paleozoic era gave rise to hard-shelled organisms, vertebrates, amphibians ...

Around 370 million years ago, Earth gradually descended into the longest lived and probably the most intense ice age ...

After Keppie (2000). The Appalachian orogen of North America is divisible with some controversy into five tectonolithologic zones which range in age from Late Precambrian through the Early Paleozoic ...