Carboniferous

The Carboniferous lasted from about 360 million to 286 million years ago. This period is subdivided into two periods, the Older Carboniferous, or Mississippian Period (about 360–320 million years ago), and the Younger Carboniferous, or Pennsylvanian Period (about 320–286 million years ago). During this time the first reptiles and seed-bearing plants appeared, and there were extensive coral reefs and coal-forming swamp forests