The Devonian Period (after Devon, England) began about 409 million years ago and ended about 363 million years ago. During this time, Europe and North America were still drifting together, and the northern Appalachians were being formed. North America was mostly tropical or subtropical, and numerous shallow, saltwater seas surrounded the coasts.

      Classic Fossil-Bearing Sites

      Silica Shale, Ohio
      Bundenbach, Germany
      Cleveland Shale, Ohio
      Rhynie, Scotland

      Astroblemes

      A number of impact structures of Devonian age are found on Earth. A 10 km structure from about 400 mya is found in Quebec; a 13 km structure dated to less than 400 mya is found in the Northwest Territories of Canada; and a 15 km craterform structure dated to 380 mya is found in Kaluga, Russia.

      Three larger impact sites are known from the Upper Devonian: a 52 km structure in Sweden (368 mya), a 100 km structure (365 mya) near Shanghai, China, and a 46 km structure about 360 million years old in Quebec. The Devonian ended with a mass extinction which eliminated about 25% of all families. It is possible that these impacts directly influenced that extinction.

      Significant Events

      Sharks and Bony Fish

      The first sharks and bony fishes appeared in the Devonian, which is frequently called the "Age of Fishes."

      Rise of Amphibians

      It was during the Devonian that the first colonization of the land by vertebrates occurred. Amphibians like Ichthyostega, while predominantly aquatic, had the physical capabilities necessary for life on land.

      Plant Diversification

      The first land plants appeared in the Silurian, but it was in the Devonian that many new forms first appeared. The lycopods, bryophytes, sphenophytes, and pteridophytes all appeared in the Devonian. Among these were the first seed plants, those that could reproduce in the absence of water.

      Devonian Graphics

       

       

       

       Devonian Sea

       Cladoselache

       Dinichthys

           

       

       

       

       Dinichthys

       Crinoid

       Crinoid

           

       

       

       

       Zaphrentis

       Trimerus

       Kentuckia

           

       

       

       

       Dolatocrinus

       Trilobites

       Anchiopella

           

       

       

       

       Goldringia

       Corals and Crinoids

       Terataspis

           

       

       

      		  

       Hexagonaria

       Phacops

      		  
           

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