A Silurian mystery - Four Key Questions


How did the skeletons and shells of the animals get broken up?

Rough sea with waves

These creatures lived in the sea. Storm waves can cause a lot of damage to a reef, rapidly smashing corals and sponges and everything living on and around them.

There are always currents flowing which could break up weakened or dead reef organisms and deposit them some distance from where they lived.




Were they broken and buried where they lived, or have they been moved?

Reef core

The rock could have been formed from broken debris of dead reef creatures and mud which collected at the bottom of a slope, or at the reef core.

There are always currents flowing which could break up weakened or dead reef organisms and deposit them some distance from where they lived.




Did they all live together in the same part of the reef or have they been moved from different places?

If the animals were moved by currents, they could have been washed together from lots of places.

fragments of bryozoans, brachiopods and a crinoid stem

Here are some fragments of broken bryozoans, brachiopods and a small piece of crinoid stem. They are fragile and easily broken by currents. They are also relatively light, so may have been moved from where they were living. The brachiopods, corals and crinoids may not have even been living close to each other.




Were they already dead when they were moved?

Trilobite enrolled

Some of the animals may have been alive and died because they were caught up in a storm current or an undersea mudslide which buried them together with fragments of skeletons of animals which were already dead.

This trilobite is partly enrolled, suggesting that it is a fossil of a whole animal rather than a moulted exoskeleton, which is a common feature of trilobite fossils. Trilobites probably rolled up to protect themselves from danger, rather like modern woodlice. The fact that it has been fossilised in this position suggests that it might have been either buried alive or buried very rapidly after death.




Final summing up ...

Wenlock Creatures

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