Graptolites
The graptolites are an extinct group of sea organisms that first appeared
during the mid Cambrian period. Their colonies varied widely in shape and
are now preserved as flattened impressions.
Although often looking like little more than pencil lines on slate, these
long extinct animals are more closely related to the vertebrates than many
other more familiar types of soft-bodied animals.
Graptolites had a worldwide distribution and evolved very rapidly, making
them important zone fossils used to date and correlate rock sequences around
the world.
These can be found at many beaches, I have seen a lot at Abereiddy Bay in
Wales.
Silurian graptolites were planktonic which means that they floated in the
seawater and would have drifted with the currents. They would have been
common in the seas of the world and would have fed by filtering small
particles from the water. |
