Lepidodendron

There has been a fossilised tree root in Sheffield Botanical Gardens for as long as I can remember. It was not until they put up new signs earlier this year that it's significance became clear.

Clubmosses - fossilised plants that became coal

This is the fossil root of a giant clubmoss called a Lepidodendron that lived about 300 million years ago. It was found in the rocks between the coal seams that were dug out when Sheffield's railway station was being built in the late 1860s. Clubmosses were some of the earliest vascular plants. Today clubmosses still exist but they are small plants that usually grow in boggy areas. Fossils are usually formed when an organism dies and the contents of its cells are replaced with rock forming minerals. This fossil root was surrounded by hardened sediments before the tissues rotted away leaving a hollow mould which was filled with fine sand forming a perfect replica of the original root. During the Carboniferous period Sheffield was covered with vast forests of clubmosses that grew up to 30 meters tall. When they died they piled up and were turned to coal as they were buried and compressed. This coal was mined in the Sheffield area for fuel.

Posted with Blogsy