What people look for on the beach
Cudmore Grove is known for fossil-rich deposits from several stages of the Ice Age. Shells, fossil wood and occasional small fragments of bone can be exposed by natural erosion. Finds are never guaranteed, and important fossils found here have often been discovered through specialist geological surveys rather than casual beachcombing.
Fossil shark teeth have also been reported from East Mersea's older marine sediments, but the site's principal scientific interest is its Pleistocene river and interglacial material, not a reliable supply of shark teeth for visitors.
Why the foreshore is significant
The upper sands and gravels were deposited by the ancient Thames–Medway river system around 300,000 years ago. Associated channel beds have yielded fossil wood and remains of animals including beaver and macaque. A later interglacial sequence, around 120,000 years old, has produced hippopotamus and other large-mammal remains.
These are different deposits, with different histories; the Mersea geology article explains the sequence in more detail. The Essex Field Club's site account identifies the protected geological exposure and its finds.
How to explore without damaging the site
Look from established beach access points and firm ground. Check the tide before walking along the shore and allow time to return: mud can be deep and the water advances over a shallow foreshore. Keep away from unstable cliffs, do not hammer or dig into exposures, and do not remove material from protected outcrops. Permissions may be required for collecting or sampling at a protected site.
If a find looks like a significant bone, tooth or worked flint, record where it was seen and seek advice from an appropriate local geological or archaeological body instead of disturbing the surrounding deposit. The scientific setting can be as important as the object.
Planning a visit
The country park entrance is on Broman's Lane, with signed routes to the shore. Check Explore Essex's current park information for access changes and facilities. A visit need not involve collecting anything: the changing cliff layers and the view over the Colne are worth seeing in their own right.