Cooksonia Silurian Plant Fossil

Description: During the Silurian, plants had established themselves along coastal waterways and nearshore regions, as well as places moist enough to sustain plant growth. The first were algaes (see my other offerings), but some simple plants like Cooksonia were invaders of the land. This one shows the terminal sporangium which would have produced the spores allowing it to reproduce and so colonize the land. The earliest Cooksonia date from the Middle Silurian, and extend into the Early Devonian, a period of some 400 million years. This rare example is unusual in that it is preserved in what is termed waterlime rather than the usual clastic rock, making for an interesting example of this early invader of the land that helped set the stage for the terrestrial animals that came later. This is the LAST example I have in inventory.