Paleozoic Earth ] Back | Next >

 390 million years ago

Mean atmospheric O2
 75% of modern level

Mean atmospheric CO2
 8x pre-industrial level

Mean temperature
 6C above modern level


Paleozoic Earth - Calamites & Asteroxylon bordering a tranquil pond in twilight - Natural History Illustration Geologic Time Scale

 Era: Paleozoic
  Period: Devonian
   Epoch: Middle
    Age: Givetian


Calamites & Asteroxylon

This is how a forest of arborescent (tree-like) horsetails of the genus Calamites and Asteroxylon, a genus of the division Lycopodiophyta, may have appeared just about anywhere on the Earth 390 million years ago. The Calamites are the slender "Christmas tree" shaped plants. They grew as tall as modern conifers, though they are the ancient ancestors today's much smaller horsetails. The snake-like curlicue plants in the foreground are the now-extinct Asteroxylon, which emerged at the beginning of the Devonian period about 417 million years ago.



Copyright Walter B. Myers. All rights reserved.

Terms of use

Home | What's New | The Graphics | Information | Site Map |  ]