Pennsylvanian

The Pennsylvanian is the Upper Carboniferous epoch in the strata of North America. It comes after (above) the Mississippian, and before the Permian. The Pennsylvanian started about 323 million years ago (mya), and ended about 299 mya.

The coal measures, which give the Carboniferous its name, are the remains of peat formed by dense tropical wetland forests. They were formed in the Pennsylvanian, from about 315–300 million years years ago.

These forests were on the equator, and the wetlands, which are always low-lying, stretched from North America in the west, through what is now Europe to China in the east, because these continents were all together at the time (Laurussia). The river plain which was the heart of the wetland stretched 5000km from eastern Canada to Ukraine, and was 700km wide.^[1]p6 This would make the Pennsylvanian basin larger than any wetlands on Earth today.

The characteristic vertebrates of the coal measures were amphibia, and the plants were mostly giant clubmosses such as Lepidodendron.^[2]

1. ↑ Thomas B.A. & Cleal C.J. 1993. The coal measure forests. National Museum of Wales.
2. ↑ C.J. Cleal & B.A. Thomas 1994. Plants of the British coal measures. The Palaeontological Association.