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The Chalk cliffs and foreshore around the Seven Sisters area reveal a diverse ecosystem dating from the Late Cretaceous epoch, 87-84 million years ago.
All chalk is made up of fossils but the majority are very small ones. The Seven sisters’ area is world famous for its highly fossiliferous chalk, which is packed with a wide range of different echinoids (sea urchins often known as Shepherd's crowns), brachiopods (symmetrical shells), bivalves (Oysters), ammonites (coiled shells), crinoids and sponges; less common finds include crustacean burrows lined with fish scales and starfish remains (among others). This is one of the best chalk locations in Europe for its variety of fossils and is recommended to all keen chalk fossil hunters.
Ammonite: “Ammonite Asteroceras” by Dlloyd is licensed under CC BY-SA 3.0.
Also, in the area but just outside the chalk you can find petrified forests dinosaur bones and footprints, horsetail stems and other plants, and fish remains.
In fact, the first known herbivore dinosaur, an Iguanodon, was found in slightly older Cretaceous rocks of the Wealden sandstone at Cuckfield just some 20 miles inland. The man who discovered it, Gideon Mantell, was born in Lewes.
Image: "Doctor Gideon Mantell (3640608793).jpg" by Simon Harriyott from Uckfield, England is licensed under CC BY 2.0.
At the end of the Cretaceous period around 65m years ago, there was a mass extinction of many species (perhaps 75% of all species were lost) which we believe was due to an asteroid impact in the Yucatan peninsula of Mexico. The Cretaceous saw the end of dinosaurs and ammonites amongst many other species on Earth. Only 13% of the chalk-building coccolithophore species remained alive.
The most productive and safest place to search for fossils is on the Seaford and Seven Sisters foreshore at low tide. Chalk boulders and flint nodules are scattered along the entire stretch, providing a constant supply of fossils.
Image: Seven Sisters from the beach by benaston is licensed under CC BY 2.0
Do not stand at the base of cliffs which are known to fall without notice. Having said that fresh falls are often a great source of fossils.
Please note the beach platform and cliffs are assigned SSSI status, which requires visitors to avoid damaging (including hammering) the area. Collecting efforts should be directed towards the loose boulders and pebbles on the foreshore.
Image: Walk the Chalk Fossils by Chris Cook
As with all coastal locations, a fossil hunting trip is best timed to coincide with a falling or low tide. Always allow plenty of time to return to non-tidal land before the tide comes in.
Image: Seaford view by Ben124. is licensed under CC BY 2.0.
A good pair of walking boots will protect you from ankle sprains, provide more grip on slippery surfaces and keep you dry in wet conditions.
It’s a good idea to spend some time considering the tools and equipment you’re likely to require while fossil hunting.
Hammer: A strong hammer will be required to split prospective rocks.
Chisel: A chisel is required in conjunction with a hammer for removing fossils from the chalk
Safety glasses: While hammering rocks there’s a risk of injury from rock splinters unless the necessary eye protection is worn.
Strong bag: When considering the type of bag to use it’s worth setting aside one that will only be used for fossil hunting, rocks are usually dusty or muddy and will make a mess of anything they come in contact with.
Chalk is not only an amazing source of fossils but also is soft and great for carving. Some of the first human artefacts found were carved from chalk some 4000 or more years ago. Why not try making an artefact of your own from chalk?
Text kindly supplied by Chris Cook
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