Early Ordovician

The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages. Provided by Wikipedia