Trace fossil Burrow
Burrow, not bone!
Thalassinoides is a large, branching burrow made by a shrimp. It is often filled with sediment that hardens, or is preserved in a different way to the rock around it. In this example, the branching ends look like the swollen ends of a bone, but it is not. Burrows like Thalassinoides are really useful in helping to determine the environment in which the rock formed. Today, identical burrows are found in shallow tropical and semi-tropical water and therefore it is not unreasonable to suggest that these rocks formed in a similar environment millions of years ago.
Find out more on the trace fossils page.