Silurian

The Silurian is a major division of the geologic timescale that extends from the end of the Ordovician period, about 443.7 million years ago (mega years ago, mya), to the beginning of the Devonian period, about 416.0 mya (ICS 2004). As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by 5-10 million years. The base of the Silurian is set at a major extinction event where 60% of marine species were wiped out. See Ordovician-Silurian extinction events.

Related Topics:
Geologic timescale - Ordovician - Devonian - Geologic - Rock - Extinction event - Ordovician-Silurian extinction events

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