Silurian Period
443.8 – 419.2 million years ago · Paleozoic Era
The Silurian was a time of recovery after the end-Ordovician extinction. Warm seas returned, reefs rebuilt, and life made decisive steps onto land.
At a glance
- Began
- 443.8 Ma
- Ended
- 419.2 Ma
- Duration
- 24.6 million years
- Era
- Paleozoic
- Climate state
- Greenhouse (warm, little or no polar ice)
- Land above sea level (PaleoDEM)
- ~20.3%
- Dinosaurs on our map
- 0
The world in the Silurian
Open the interactive map at 430 Ma → Elevation view
What Earth was like
Laurentia and Baltica collided to form Laurussia (the "Old Red Sandstone continent"), raising the Caledonian mountains in what are now Scotland, Scandinavia and Greenland. Gondwana still dominated the southern hemisphere.
Climate
With the ice sheets melted, the Silurian was largely warm and stable, with high sea levels and extensive tropical reefs. Short cooler episodes occurred, but no major ice age.
Life
The first vascular plants, such as Cooksonia, appeared: small stems only a few centimeters tall. Millipedes and early arachnids followed them onto land. In the sea, jawed fish diversified and giant sea scorpions (eurypterids) became top predators.
Dinosaurs of the Silurian
There were no dinosaurs yet. The first dinosaurs appear in the Late Triassic, around 233 million years ago.
How it ended
The Silurian ended quietly compared with other periods, at 419.2 million years ago, with the start of the Devonian.
Key facts
- Cooksonia is one of the oldest known vascular plants.
- Some eurypterids grew over 2 meters long.
- Jawed fish, the ancestors of nearly all living vertebrates, spread widely.
Data: land and sea
Across the Silurian, an average of 20.3% of Earth’s surface stood above reconstructed sea level (range 18.2–22.9%). Today the same model gives 31.8%.
Where this data comes from
- Continent positions: GPlates Web Service, Merdith et al. (2021) full-plate model, used for 250–540 Ma.
- Elevation and shorelines: PALEOMAP PaleoDEMs, Scotese & Wright (2018), doi:10.5281/zenodo.5460860, CC BY 4.0.
- Period boundaries: ICS International Chronostratigraphic Chart (2023/09).
These are scientific reconstructions, not observations. Uncertainty grows the further back in time you go. About & data sources
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