Temperature: 20 °C
Atmospheric oxygen: 15%
The Devonian is the fourth of the six periods of the Paleozoic era. It was a relatively warm period, periodically disrupted by glaciations. The weather was very arid, particularly along the equator. By the Devonian, the Early Paleozoic oceans were closing, forming a “pre-Pangea”. Fish were able to migrate from the southern hemisphere continents to North America and Europe. Forests grew for the first time in the equatorial regions of what is now Artic Canada. It ended with a major extinction which wiped out half of all genera.