Silurian Period FACT FILE

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.4 ± 1.5 million years ago (mya), to the beginning of the Devonian Period, about 419.2 ± 3.2 mya.

The Silurian Period started a mass extinction.


A marine transgression marked the end of the Silurian Period.

The Silurian is a time when many biologically significant events occurred. In the oceans, there was a widespread radiation of crinoids, a continued proliferation and expansion of the brachiopods, and the oldest known fossils of coral reefs. As mentioned earlier, this time period also marks the wide and rapid spread of jawless fish, along with the important appearances of both the first known freshwater fish and the appearance of jawed fish. Other marine fossils commonly found throughout the Silurian record include trilobites, graptolites, conodonts, corals, stromatoporoids, and molluscs.


The BBC Nature website has a very good section on the Silurian.  


Use this button to visit the BBC Nature website:

*Based on 'The Geologic Time Scale 2012' by F M Gradstein, J G Ogg, M Schmitz & G Ogg (2012), with additions. Credit: British Geological Survey