The Freakiest of October The Carboniferous period

The Carboniferous is famed for having the highest atmospheric oxygen levels the Earth has ever experienced and for the evolution of the first reptiles. Plants grew and died at such a great rate that they eventually became coal. The period was originally called the Coal Measures after its proliferation of coal-bearing rocks. Though the Carboniferous started off warm - hence its lush coal forests - the temperature began to drop and the polar regions were plunged into an ice age that lasted millions of years. In North America, the Carboniferous is divided into two epochs, the Mississippian and the Pennsylvanian.