Ordovician Time Slices
Ordovician 1
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Ordovician 1: Early Ordovician (Tremadocian and Floian stages) (about 488-472 million years)
Ordovician 2: Dapingian (about 472-468 million years)
Ordovician 3: Darriwillian (about 468-461 million years)
Ordovician 4: Late Ordovician (Sandbian through Hirnantian stages) (about 461-444 million years)