The Silurian Period (from the name of an ancient British tribe, the Silures) lies between approximately 439 mya and 409 mya.During this time, a great deal of volcanic activity was taking place, generating lava flows and ash. No new major groups of organisms appeared at this time, with old groups flourishing or declining.
Classic Fossil-Bearing Sites
Wadi Ram, Jordon
Brandon Bridge, Wisconsin
Brownsport Group, Tennessee
A 10 km impact structure from 425 mya is located at Lac Couture, Quebec.
Significant Events
Life on Land
It was during the Silurian that the first life came out of the water and colonized the land. Increased ozone from photosynthetic water plants provided protection from ultraviolet rays, make the terrestrial environment hospitable to those organisms that could prevent desiccation.
First Vascular Plants
The first plants with internal vascular channels appeared in the Silurian. Plants were now able to transport food and gases to other parts of their structure, allowing for a significant increase in size.
First Insects
The insects arose in the Silurian, probably becoming the first animal forms to venture out of the water.
First Jawed Vertebrates
The first fish with jaws appeared during the Silurian, providing a much better predator capability and ultimately giving rise to the vertebrates known today.
Silurian Graphics
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| Baragwanathia |
Birkenia |
Cooksonia |
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| Crinoid |
Crinoid |
Eurypterid |
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| Snail |
Early Plant |
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