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 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 & Drepanophycus against a clear sky & waxing gibbous moon (Horsetail, Equisetum) - Natural History Illustration Geologic Time Scale

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


Calamites & Drepanophycus

Arborescent (tree-like) horsetails of the genus Calamites of varying size (10 to 50 feet tall) populate lowlands near the brackish waters of an inland sea 390 million years ago. Closer to the ground at about 6 feet tall is a variety of Drepanophycus, a genus of the division Lycopodiophyta, ancient plants that preceded the Calamites by about 20 million years and coexisted with them for 35 million years.



Copyright Walter B. Myers. All rights reserved.

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