Silurian Period (Paleozoic 3)

Paleozoic Era 3: Silurian Period – Unsettled Conditions

Key Events

  • Though relatively short, the Silurian Period is a time of volatile changes.
  • Major extinction events are followed by life bouncing back.
  • Fish develop moveable jaws, enabling new ways of feeding, and bony species of fish emerge.
  • On land, small mosses and plants appear beside lakes, streams and coastlines.
  • Millipedes and spider-like arachnids (spider-like) evolve.
Illustration of life during the Silurian Period. Copyright: Vix Southgate

Facts, Debates & Trivia

  • The name comes from an ancient Welsh tribe, the Silures, who lived where rocks formed during this period are found.
  • The change in sea-levels over the Silurian Period may beas much as 140 metres (taller than the Great Pyramid of Giza).
  • Islands, reefs and warm, shallow seas provide environments where life can recover from extinctions caused by the changing conditions.


  • The climate undergoes several dramatic fluctuations.
  • High sea levels over relatively flat continents result in many island chains.
The Earth 430 million years ago. The red dot marks the location of what will eventually become Cornwall. Credit: C.R. Scotese/I. Webster


443.8 – 419.2 million years ago

(26.4 million years)

1 metre = 10 million years

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